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Hepatocellular carcinoma is increasingly important in the United States as the incidence rate rose over the last 30 years. C3HeB/FeJ mice serve as a unique model to study hepatocellular carcinoma tumorigenesis because they mimic human hepatocellular carcinoma with delayed onset, male gender bias, approximately 50% incidence, and susceptibility to tumorigenesis is mediated through multiple genetic loci. Because a human O(6)-methylguanine-DNA methyltransferase (hMGMT) transgene reduces spontaneous tumorigenesis in this model, we hypothesized that hMGMT would also protect from methylation-induced hepatocarcinogenesis. To test this hypothesis, wild-type and hMGMT transgenic C3HeB/FeJ male mice were treated with two monofunctional alkylating agents: diethylnitrosamine (DEN; 0.025 μmol/g body weight) on day 12 of life with evaluation for glucose-6-phosphatase-deficient (G6PD) foci at 16, 24, and 32 weeks or N-methyl-N-nitrosurea (MNU; 25 mg MNU/kg body weight) once monthly for 7 months starting at 3 months of age with evaluation for liver tumors at 12 to 15 months of age. No difference in abundance or size of G6PD foci was measured with DEN treatment. In contrast, it was unexpectedly found that MNU reduces liver tumor prevalence in wild-type and hMGMT transgenic mice despite increased tumor prevalence in other tissues. hMGMT and MNU protections were additive, suggesting that MNU protects through a different mechanism, perhaps through the cytotoxic N7-alkylguanine and N3-alkyladenine lesions which have low mutagenic potential compared with O(6)-alkylguanine lesions. Together, these results suggest that targeting the repair of cytotoxic lesions may be a good preventative for patients at high risk of developing hepatocellular carcinoma., (©2015 American Association for Cancer Research.)

Background: We explored whether, the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) coronary and abdominal risk scores measured at 18 to 30 years of age and changes in these scores would more strongly predict coronary artery calcium (CAC) and abdominal aortic calcium (AAC) assessed 25 years later, than scores measured 25 years later., Methods and Results: In the Coronary Artery Risk Development in Young Adults (CARDIA) study, 3008 participants had measurements of risk score components at 5-year intervals beginning at 18 to 30 years of age. CAC and AAC were assessed at 43 to 55 years of age. Odds ratios (ORs) for the presence and extent of CAC/AAC per/point higher score and c-statistics for predicting CAC/AAC were calculated. The prevalence of CAC was 28% and AAC was 53%. For each 1 point higher PDAY score, the odds of CAC were higher using baseline scores than year 25 scores (OR, 1.29; 95% confidence interval [CI], 1.25-1.33 versus OR, 1.12; 95% CI, 1.11-1.14). For AAC, ORs at years 0 and 25 were similar (OR, 1.29; 95% CI, 1.24-1.34 versus OR, 1.22; 95% CI, 1.19-1.26). C-statistic for CAC prediction was higher at year 0 than year 25 (0.731 versus 0.705) but similar at years 0 and 25 for AAC (0.665 versus 0.670). ORs for CAC were highest at baseline, and, for AAC, ORs were highest at year 10. Including change in PDAY scores with baseline scores improved prediction., Conclusions: Atherosclerosis risk and change in risk assessed in young adulthood years before subclinical atherosclerosis imaging provide strong prediction of future subclinical atherosclerosis. CAC and AAC reflect chronic risk exposure in addition to risk measured at the time of study., (© 2015 American Heart Association, Inc.)

Purpose: The purpose of this study was to evaluate and compare the efficacy of cone-beam computed tomography (CBCT) and digital intraoral radiography in diagnosing simulated small external root resorption cavities., Materials and Methods: Cavities were drilled in 159 roots using a small spherical bur at different root levels and on all surfaces. The teeth were imaged both with intraoral digital radiography using image plates and with CBCT. Two sets of intraoral images were acquired per tooth: orthogonal (PA) which was the conventional periapical radiograph and mesioangulated (SET). Four readers were asked to rate their confidence level in detecting and locating the lesions. Receiver operating characteristic (ROC) analysis was performed to assess the accuracy of each modality in detecting the presence of lesions, the affected surface, and the affected level. Analysis of variation was used to compare the results and kappa analysis was used to evaluate interobserver agreement., Results: A significant difference in the area under the ROC curves was found among the three modalities (P=0.0002), with CBCT (0.81) having a significantly higher value than PA (0.71) or SET (0.71). PA was slightly more accurate than SET, but the difference was not statistically significant. CBCT was also superior in locating the affected surface and level., Conclusion: CBCT has already proven its superiority in detecting multiple dental conditions, and this study shows it to likewise be superior in detecting and locating incipient external root resorption.

Children are vulnerable to environmental mutagens, and the developing germline could also be affected. However, little is known about whether exposure to environmental mutagens in childhood will result in increased germline mutations in subsequent adult life. In the present study, male transgenic lacI mice at different ages (7, 25 and 60 days old) were treated with a known environmental mutagen (benzo[a]pyrene, B[a]P) at different doses (0, 50, 200 or 300 mg/kg body weight). Mutant frequency was then determined in a meiotic cell type (pachytene spermatocyte), a post-meiotic cell type (round spermatid) and epididymal spermatozoa after at least one cycle of spermatogenesis. Our results show that 1) mice treated with B[a]P at 7 or 25 days old, both being pre-adult ages, had significantly increased mutant frequencies in all spermatogenic cell types tested when they were 60 days old; 2) spermatogenic cells from mice treated before puberty were more susceptible to B[a]P-associated mutagenesis compared to adult mice; and 3) unexpectedly, epididymal spermatozoa had the highest mutant frequency among the spermatogenic cell types tested. These data show that pre-adult exposure to B[a]P increases the male germline mutant frequency in young adulthood. The data demonstrate that exposure to environmental genotoxins at different life phases (e.g., pre-adult and adult) can have differential effects on reproductive health.

Genetically based diseases constitute a major human health burden, and de novo germline mutations represent a source of heritable genetic alterations that can cause such disorders in offspring. The availability of transgenic rodent systems with recoverable, mutation reporter genes has been used to assess the occurrence of spontaneous point mutations in germline cells. Previous studies using the lacI mutation reporter transgenic mouse system showed that the frequency of spontaneous mutations is significantly lower in advanced male germ cells than in somatic cell types from the same individuals. Here we used this same mutation reporter transgene system to show that female germ cells also display a mutation frequency that is lower than that in corresponding somatic cells and similar to that seen in male germ cells, indicating this is a common feature of germ cells in both sexes. In addition, we showed that statistically significant differences in mutation frequencies are evident between germ cells and somatic cells in both sexes as early as mid-fetal stages in the mouse. Finally, a comparison of the mutation frequency in a general population of early type A spermatogonia with that in a population enriched for Thy-1-positive spermatogonia suggests there is heterogeneity among the early spermatogonial population such that a subset of these cells are predestined to form true spermatogonial stem cells. Taken together, these results support the disposable soma theory, which posits that genetic integrity is normally maintained more stringently in the germ line than in the soma and suggests that this is achieved by minimizing the initial occurrence of mutations in early germline cells and their subsequent gametogenic progeny relative to that in somatic cells.

Each of three cone beam computed tomography (CBCT) machines offer a small field of view (FOV); Promax, Accuitomo 3D, and Kodak 9000. The objectives were to determine, when using a small FOV, the difference in contrast-to-noise ratios (CNR) of images obtained from different machines and different scan settings within each machine. A phantom made of a dry mandible with an epoxy resin based substitute (ERBS) block was used. The ERBS block was fixed to the lingual cortex in the posterior left mandible. Water was used to simulate soft tissue. Twenty scans were acquired. CNR was calculated as the difference in density of the ERBS block and a control area divided by the standard deviation of the difference. The CNR obtained from images acquired with the Promax machine (voxel size of 0.2 mm) was higher than the other machines (voxel sizes 0.076, 0.08, or 0.125 mm) when using a small FOV. The Accuitomo 360° scan had higher CNR than the Accuitomo 180° scan due to the doubling of the number of basis images acquired. Smaller voxel size does not necessarily lead to enhanced CNR. Increasing the number of basis images did increase the CNR.

During the first wave of spermatogenesis, and in response to ionizing radiation, elevated mutant frequencies are reduced to a low level by unidentified mechanisms. Apoptosis is occurring in the same time frame that the mutant frequency declines. We examined the role of apoptosis in regulating mutant frequency during spermatogenesis. Apoptosis and mutant frequencies were determined in spermatogenic cells obtained from Bax-null or Trp53-null mice. The results showed that spermatogenic lineage apoptosis was markedly decreased in Bax-null mice and was accompanied by a significantly increased spontaneous mutant frequency in seminiferous tubule cells compared to that of wild-type mice. Apoptosis profiles in the seminiferous tubules for Trp53-null were similar to control mice. Spontaneous mutant frequencies in pachytene spermatocytes and in round spermatids from Trp53-null mice were not significantly different from those of wild-type mice. However, epididymal spermatozoa from Trp53-null mice displayed a greater spontaneous mutant frequency compared to that from wild-type mice. A greater proportion of spontaneous transversions and a greater proportion of insertions/deletions 15 days after ionizing radiation were observed in Trp53-null mice compared to wild-type mice. Base excision repair activity in mixed germ cell nuclear extracts prepared from Trp53-null mice was significantly lower than that for wild-type controls. These data indicate that BAX-mediated apoptosis plays a significant role in regulating spontaneous mutagenesis in seminiferous tubule cells obtained from neonatal mice, whereas tumor suppressor TRP53 plays a significant role in regulating spontaneous mutagenesis between postmeiotic round spermatid and epididymal spermatozoon stages of spermiogenesis.

Cloning by somatic cell nuclear transfer (SCNT) circumvents processes that normally function during gametogenesis to prepare the gamete genomes to support development of new progeny following fertilization. One such process is enhanced maintenance of genetic integrity in germ cells, such that germ cells typically carry fewer spontaneously acquired mutations than somatic cells in the same individual. Thus, embryos produced from somatic cells by SCNT could directly inherit more mutations than naturally conceived embryos. Alternatively, they could inherit epigenetic programming that predisposes more rapid accumulation of de novo mutations during development. We used a transgenic mouse system to test these possibilities by producing cloned midgestation mouse fetuses from three different donor somatic cell types carrying significantly different initial frequencies of spontaneous mutations. We found that on an individual locus basis, mutations acquired spontaneously in a population of donor somatic cells are not likely to be propagated to cloned embryos by SCNT. In addition, we found that the rate of accumulation of spontaneous mutations was similar in fetuses produced by either natural conception or cloning, indicating that cloned fetuses do not acquire mutations more rapidly than naturally conceived fetuses. These results represent the first direct demonstration that the process of cloning by SCNT does not lead to an increase in the frequency of point mutations. These results also demonstrate that epigenetic mechanisms normally contribute to the regulation of genetic integrity in a tissue-specific manner, and that these mechanisms are subject to reprogramming during cloning.

Gametes carry the DNA that will direct the development of the next generation. By compromising genetic integrity, DNA damage and mutagenesis threaten the ability of gametes to fulfill their biological function. DNA repair pathways function in germ cells and serve to ameliorate much DNA damage and prevent mutagenesis. High base excision repair (BER) activity is documented for spermatogenic cells. DNA polymerase-beta (POLB) is required for the short-patch BER pathway. Because mice homozygous null for the Polb gene die soon after birth, mice heterozygous for Polb were used to examine the extent to which POLB contributes to maintaining spermatogenic genomic integrity in vivo. POLB protein levels were reduced only in mixed spermatogenic cells. In vitro short-patch BER activity assays revealed that spermatogenic cell nuclear extracts obtained from Polb heterozygous mice had one third the BER activity of age-matched control mice. Polb heterozygosity had no effect on the BER activities of somatic tissues tested. The Polb heterozygous mouse line was crossed with the lacI transgenic Big Blue mouse line to assess mutant frequency. The spontaneous mutant frequency for mixed spermatogenic cells prepared from Polb heterozygous mice was 2-fold greater than that of wild-type controls, but no significant effect was found among the somatic tissues tested. These results demonstrate that normal POLB abundance is necessary for normal BER activity, which is critical in maintaining a low germline mutant frequency. Notably, spermatogenic cells respond differently than somatic cells to Polb haploinsufficiency.

Assisted reproductive technologies (ARTs) have now contributed to the birth of >3 million babies worldwide, but concerns remain regarding the safety of these methods. We have used a transgenic mouse model to examine the effects of ARTs on the frequency and spectrum of point mutations in midgestation mouse fetuses produced by either natural reproduction or various methods of ART, including preimplantation culture, embryo transfer, in vitro fertilization, intracytoplasmic sperm injection, and round spermatid injection. Our results show that there is no significant difference in the frequency or spectrum of de novo point mutations found in naturally conceived fetuses and fetuses produced by in vitro fertilization, intracytoplasmic sperm injection, or round spermatid injection. These results, based on analyses of a transgenic mouse system, indicate that with respect to maintenance of genetic integrity, ARTs appear to be safe.

The basic tenet of several theories on aging is increasing genomic instability resulting from interactions with the environment. Chromosomal aberrations have been used as classic examples of increasing genomic instability since they demonstrate an increase in numerical and structural abnormalities with age in many species including humans. This accumulating damage may augment many aging processes and initiate age-related diseases, such as neoplasias. Calorie restriction (CR) is one of the most robust interventions for reducing the frequency of age-related diseases and for extending life span in many short-lived organisms. However, the mechanisms for the anti-aging effects of CR are not yet well understood. A study of rhesus monkeys was begun in 1987 to determine if CR is also effective in reducing the frequency of age-related diseases and retarding aging in a long-lived mammal. Male monkeys were begun on the diet in 1987, and females were added in 1992 to examine a possible difference in response to CR by sex. The CR monkeys have been maintained for over 10 years on a low-fat nutritional diet that provides a 30% calorie reduction compared to a control (CON) group. Because of the greater similarity of nonhuman primates to humans in life span and environmental responses to diet compared with those of rodents, the rhesus monkey provides an excellent model for the effects of CR in humans. This study examined the effects of CR on chromosomal instability with aging. Significant age effects were found in both CR and CON groups for the number of cells with aneuploidy: old animals had a higher loss and a higher gain than young animals. However, there was no effect of age on chromosomal breakage or structural aberrations in either diet group. Diet had only one significant effect: the CR group had a higher frequency of chromatid gaps than did the CON group. CR, implemented in adult rhesus monkeys, does not have a major effect on the reduction of numerical or structural aberrations related to aging.

Germ cells perform a unique and critical biological function: they propagate the DNA that will be used to direct development of the next generation. Genetic integrity of germ cell DNA is essential for producing healthy and reproductively fit offspring, and yet germ cell DNA is damaged by endogenous and exogenous agents. Nucleotide excision repair (NER) is an important mechanism for coping with a variety of DNA lesions. Little is known about NER activity in spermatogenic cells. We expected that germ cells would be more efficient at DNA repair than somatic cells, and that this efficiency may be reduced with age when the prevalence of spontaneous mutations increases. In the present study, NER was measured in defined spermatogenic cell types, including premeiotic cells (A and B type spermatogonia), meiotic cells (pachytene spermatocytes), and postmeiotic haploid cells (round spermatids) and compared with NER in keratinocytes. Global genome repair and transcription-coupled repair subpathways of NER were examined. All spermatogenic cell types from young mice displayed good repair of (6-4) pyrimidone photoproducts, although the repair rate was slower than in primary keratinocytes. In aged mice, repair of 6-4 pyrimidone photoproducts was depressed in postmeiotic cells. While repair of cyclobutane pyrimidine dimers was not detected in spermatogenic cells or in keratinocytes, the transcribed strands of active genes were repaired with greater efficiency than nontranscribed strands or inactive genes in keratinocytes and in meiotic and postmeiotic cells; spermatogonia displayed low to moderate ability to repair cyclobutane pyrimidine dimers on both DNA strands regardless of transcriptional status. Overall, the data suggest cell type-specific NER activity during murine spermatogenesis, and our results have possible implications for germ cell aging.

Objective: To determine the associations among serum C-reactive protein (CRP) concentration, age, sex, risk factors for coronary heart disease (CHD), and atherosclerosis in young people., Methods and Results: In 1244 subjects 15 to 34 years of age, we measured gross atherosclerotic lesions in the right coronary artery (RCA) and abdominal aorta (AA) and American Heart Association (AHA) lesion grade in the left anterior descending (LAD) coronary artery; serum CRP, lipoprotein cholesterol, and thiocyanate (for smoking) concentrations; intimal thickness of renal arteries (for hypertension); glycohemoglobin (for hyperglycemia); and body mass index (for obesity). Serum CRP levels increased with age, were higher in women than in men, and were positively related to obesity and hyperglycemia. Serum CRP > or =10 mg/L was associated with more extensive gross raised lesions in the RCA after age 25 and in the AA after age 30. Serum CRP > or =3 was associated with a greater prevalence of AHA grade 5 lesions in the proximal LAD coronary artery after age 25. The associations of CRP with lesions were independent of the traditional CHD risk factors., Conclusions: Serum CRP level is independently associated with advanced atherosclerosis in young persons.

Germ line DNA directs the development of the next generation and, as such, is profoundly different from somatic cell DNA. Spermatogenic cells obtained from young adult lacI transgenic mice display a lower spontaneous mutant frequency and greater in vitro base excision repair activity than somatic cells and tissues obtained from the same mice. However, spermatogenic cells from old lacI mice display a 10-fold higher mutant frequency. This increased spontaneous mutant frequency occurs coincidentally with decreased in vitro base excision repair activity for germ cell and testicular extracts that in turn corresponds to a decreased abundance of AP endonuclease. To directly test whether a genetic diminution of AP endonuclease results in increased spontaneous mutant frequencies in spermatogenic cell types, AP endonuclease heterozygous (Apex(+/-)) knockout mice were crossed with lacI transgenic mice. Spontaneous mutant frequencies were significantly elevated (approximately twofold) for liver and spleen obtained from 3-month-old Apex(+/-) lacI(+) mice compared to frequencies from Apex(+/+) lacI(+) littermates and were additionally elevated for somatic tissues from 9-month-old mice. Spermatogenic cells from 9-month-old Apex(+/-) lacI(+) mice were significantly elevated twofold compared to levels for 9-month-old Apex(+/+) lacI(+) control mice. These data indicate that diminution of AP endonuclease has a significant effect on spontaneous mutagenesis in somatic and germ line cells.

Loss of weight, often of unknown cause and culminating in death, commonly occurs in humans at advanced ages. Rats that live to old ages, such as the Fischer 344 (F344) strain, also exhibit a terminal loss in body weight. A presently held hypothesis is that the terminal weight loss in the F344 rat model is due to reduced food intake because of an alteration in hypothalamic function resulting in early satiation. We report findings on terminal weight loss and food intake in male F344 rats fed ad libitum (AL group) or a life-prolonging dietary regimen in which caloric intake was restricted (DR group). Rats in both dietary groups that did not exhibit a terminal weight loss died at younger ages than those exhibiting the loss. Terminal weight loss in the AL group was not associated with decreased food intake; indeed, half of the rats in this group had an increased food intake during the period of terminal weight loss. This finding is not in accord with the presently held hypothesis. In the DR group, terminal weight loss was associated with reduced food intake. Pathology (renal disease and neoplasms) did not explain the presence or absence of the association between reduced food intake and weight loss in either dietary group. The duration of the period of terminal weight loss was similar for the AL and DR groups. Apparently, restricting calories delays the occurrence but does not affect the duration of senescent terminal weight loss.

The combined observations of elevated DNA repair gene expression, high uracil-DNA glycosylase-initiated base excision repair, and a low spontaneous mutant frequency for a lacI transgene in spermatogenic cells from young mice suggest that base excision repair activity is high in spermatogenic cell types. Notably, the spontaneous mutant frequency of the lacI transgene is greater in spermatogenic cells obtained from old mice, suggesting that germ line DNA repair activity may decline with age. A paternal age effect in spermatogenic cells is recognized for the human population as well. To determine if male germ cell base excision repair activity changes with age, uracil-DNA glycosylase-initiated base excision repair activity was measured in mixed germ cell (i.e., all spermatogenic cell types in adult testis) nuclear extracts prepared from young, middle-aged, and old mice. Base excision repair activity was also assessed in nuclear extracts from premeiotic, meiotic, and postmeiotic spermatogenic cell types obtained from young mice. Mixed germ cell nuclear extracts exhibited an age-related decrease in base excision repair activity that was restored by addition of apurinic/apyrimidinic (AP) endonuclease. Uracil-DNA glycosylase and DNA ligase were determined to be limiting in mixed germ cell nuclear extracts prepared from young animals. Base excision repair activity was only modestly elevated in pachytene spermatocytes and round spermatids relative to other spermatogenic cells. Thus, germ line short-patch base excision repair activity appears to be relatively constant throughout spermatogenesis in young animals, limited by uracil-DNA glycosylase and DNA ligase in young animals, and limited by AP endonuclease in old animals.

O(6)-methylguanine (O(6)mG) is a potent mutagenic and procarcinogenic DNA lesion. Organisms have evolved with a DNA repair mechanism that largely ameliorates the deleterious effects of O(6)mG through a direct reversal mechanism by a protein termed O(6)-methylguanine-DNA methyltransferase (MGMT). However, the contribution of O(6)mG to carcinogenesis, in the absence of known exposure to agents that produce it, has not been defined. Nontransgenic C3HeB male mice have a high frequency of spontaneous liver tumors. Transgenic CeHeB/FeJ mice expressing human MGMT (hMGMT) were generated that had elevated hepatic MGMT activity. The spontaneous development of hepatocellular carcinoma was significantly reduced in those mice expressing hMGMT compared with nontransgenic C3HeB/FeJ male mice. No differences were detected in spontaneous mutant frequencies in lacI transgenes in mice carrying hMGMT compared with that without hMGMT but the proportion of GC to AT transition mutations was lower in the transgenic mice carrying hMGMT as well as lacI. Tumors that arose in C3HeB/FeJ transgenic mice were largely deficient in hMGMT protein as determined by immunohistochemistry with a monoclonal antibody directed against hMGMT. Together these data indicate that spontaneous O(6)mG lesions induced hepatocellular carcinogenesis in C3HeB/FeJ male mice. These transgenic mice represent a rare example of reduced spontaneous carcinogenesis.

Background: The strong association between coronary heart disease and dyslipoproteinemia has often overshadowed the effects of the nonlipid risk factors-smoking, hypertension, obesity, and diabetes and impaired glucose tolerance-and even led to questioning the importance of these risk factors in the presence of a favorable lipoprotein profile., Methods and Results: A cooperative multicenter study, the Pathobiological Determinants of Atherosclerosis in Youth (PDAY), examined the relation of the nonlipid risk factors to atherosclerosis in 629 men and 227 women 15 to 34 years of age who died of external causes and who had a favorable lipoprotein profile (non-HDL cholesterol <4.14 mmol/L [<160 mg/dL] and HDL cholesterol >/=0.91 mmol/L [>/=35 mg/dL]). In the abdominal aorta, smokers had more extensive fatty streaks and raised lesions than nonsmokers, and hypertensive blacks had more raised lesions than normotensive blacks. In the right coronary artery, hypertensive blacks had more raised lesions than normotensive blacks, obese men (body mass index >/=30 kg/m(2)) had more extensive fatty streaks and raised lesions than nonobese men, and individuals with impaired glucose intolerance had more extensive fatty streaks. Obese men had more severe lesions (American Heart Association grade 2 through 5) of the left anterior descending coronary artery., Conclusions: These substantial effects of the nonlipid risk factors on the extent and severity of coronary and aortic atherosclerosis, even in the presence of a favorable lipoprotein profile, support the need to control all cardiovascular risk factors.

Spermatogenic cells exhibit a lower spontaneous mutation frequency than somatic tissues in a lacI transgene and many base excision repair (BER) genes display the highest observed level of expression in the testis. In this study, uracil-DNA glycosylase-initiated BER activity was measured in nuclear extracts prepared from tissues obtained from each of three mouse strains. Extracts from mixed spermatogenic germ cells displayed the greatest activity followed by liver then brain for all three strains, and the activity for a given tissue was consistent among the three strains. Levels of various BER proteins were examined by western blot analyses and found to be consistent with activity levels. Nuclear extracts prepared from purified Sertoli cells, a somatic component of the seminiferous epithelium, exhibited significantly lower activity than mixed spermatogenic cell-type nuclear extracts, thereby suggesting that the high BER activity observed in mixed germ cell nuclear extracts was not a characteristic of all testicular cell types. Nuclear extracts from thymocytes and small intestines were assayed to assess activity in a mitotically active cell type and tissue. Overall, the order of tissues/cells exhibiting the greatest to lowest activity was mixed germ cells > Sertoli cells > thymocytes > small intestine > liver > brain.

Atherosclerosis begins in childhood as deposits of cholesterol and its esters, referred to as fatty streaks, in the intima of large muscular arteries. In some persons and at certain arterial sites, more lipid accumulates and is covered by a fibromuscular cap to form a fibrous plaque. Further changes in fibrous plaques render them vulnerable to rupture, an event that precipitates occlusive thrombosis and clinically manifest disease (sudden cardiac death, myocardial infarction, stroke, or peripheral arterial disease). In adults, elevated non-HDL-cholesterol concentrations, low HDL-cholesterol concentrations, hypertension, smoking, diabetes, and obesity are associated with advanced atherosclerotic lesions and increased risk of clinically manifest atherosclerotic disease. Control of these risk factors is the major strategy for preventing atherosclerotic disease. To determine whether these risk factors also are associated with early atherosclerosis in young persons, we examined arteries and tissue from approximately 3000 autopsied persons aged 15-34 y who died of accidental injury, homicide, or suicide. The extent of both fatty streaks and raised lesions (fibrous plaques and other advanced lesions) in the right coronary artery and in the abdominal aorta was associated positively with non-HDL-cholesterol concentration, hypertension, impaired glucose tolerance, and obesity and associated negatively with HDL-cholesterol concentration. Atherosclerosis of the abdominal aorta also was associated positively with smoking. These observations indicate that long-range prevention of atherosclerosis and its sequelae by control of the risk factors for adult coronary artery disease should begin in adolescence and young adulthood.

The raised fatty streak (fatty plaque) is the gross term for the lesion intermediate between the juvenile (flat) fatty streak and the raised lesion of atherosclerosis. We measured the percentage of intimal surface involved with flat fatty streaks, raised fatty streaks, and raised lesions in the aortas and right coronary arteries of 2876 autopsied persons aged 15 through 34 years who died of external causes. Raised fatty streaks were present in the abdominal aortas of approximately 20% of 15- to 19-year-old subjects, and this percentage increased to approximately 40% for 30- to 34-year-old subjects. Raised fatty streaks were present in the right coronary arteries of approximately 10% of 15- to 19-year-old subjects, and this percentage increased to approximately 30% for 30- to 34-year-old subjects. The percent intimal surface involved with raised fatty streaks increased with age in both arteries and was associated with high non-high density lipoprotein (HDL) and low HDL cholesterol concentrations in the abdominal aorta and right coronary artery, with hypertension in the abdominal aorta, with obesity in the right coronary artery of men, and with impaired glucose tolerance in the right coronary artery. Associations of risk factors with raised fatty streaks became evident in subjects in their late teens, whereas associations of risk factors with raised lesions became evident in subjects aged >25 years. These results are consistent with the putative transitional role of raised fatty streaks and show that coronary heart disease risk factors accelerate atherogenesis in the second decade of life. Thus, long-range prevention of atherosclerosis should begin in childhood or adolescence.

Background: This study examined whether atherosclerosis in young people is associated with the risk factors for clinical coronary heart disease (CHD). Methods and Results-Histological sections of left anterior descending coronary arteries (LADs) from 760 autopsied 15- to 34-year-old victims of accidents, homicides, and suicides were graded according to the American Heart Association (AHA) system and computerized morphometry. Risk factors (dyslipoproteinemia, smoking, hypertension, obesity, impaired glucose tolerance) were assessed by postmortem measurements. Approximately 2% of 15- to 19-year-old men and 20% of 30- to 34-year-old men had AHA grade 4 or 5 (advanced) lesions. No 15- to 19-year-old women had grade 4 or 5 lesions; 8% of 30- to 34-year-old women had such lesions. Approximately 19% of 30- to 34-year-old men and 8% of 30- to 34-year-old women had atherosclerotic stenosis > or =40% in the LAD. AHA grade 2 or 3 lesions (fatty streaks), grade 4 or 5 lesions, and stenosis > or =40% were associated with non-HDL cholesterol > or =4.14 mmol/L (160 mg/dL). AHA grade 2 or 3 lesions were associated with HDL cholesterol <0.91 mmol/L (35 mg/dL) and smoking. AHA grade 4 or 5 lesions were associated with obesity (body mass index > or =30 kg/m(2)) and hypertension (mean arterial pressure > or =110 mm Hg)., Conclusions: -Young Americans have a high prevalence of advanced atherosclerotic coronary artery plaques with qualities indicating vulnerability to rupture. Early atherosclerosis is influenced by the risk factors for clinical CHD. Long-range prevention of CHD must begin in adolescence or young adulthood.

We examined topographic distributions of atherosclerosis and their relation to risk factors for adult coronary heart disease in right coronary arteries and abdominal aortas of more than 2000 autopsied persons 15 through 34 years of age. We digitized images of Sudan IV-stained fatty streaks and of manually outlined raised lesions and computed the percent surface area involved by each lesion in each of 6 regions of each artery. In abdominal aortas of 15- to 24-year-old persons, fatty streaks involve an elongated oval area on the dorsolateral intimal surface and another oval area in the middle third of the ventral surface. Raised lesions in 25- to 34-year-old persons involve an oval area in the distal third of the dorsolateral intimal surface. In other areas of the abdominal aortas of older persons, fatty streaks occur but raised lesions are rare. In the right coronary arteries of 15- to 24-year-old persons, fatty streaks are most frequent on the myocardial aspect of the first 2 cm. Raised lesions follow a similar pattern in 25- to 34-year-old persons. High non-HDL cholesterol and low HDL cholesterol concentrations are associated with more extensive fatty streaks and raised lesions in all regions of both arteries. Smoking is associated with more extensive fatty streaks and raised lesions of the abdominal aorta, particularly in the dorsolateral region of the distal third of the abdominal aorta. Hypertension is not associated with fatty streaks in whites or blacks but is associated with more extensive raised lesions in blacks. Risk factor effects on arterial regions that are vulnerable to lesions are approximately 25% greater than risk factor effects assessed over entire arterial segments. These risk factor effects on vulnerable sites emphasize the need for risk factor control during adolescence and young adulthood to prevent or delay the progression of atherosclerosis.

We compared serum lipid and apolipoprotein predictors of atherosclerosis in cases from the multicenter study, Pathobiological Determinants of Atherosclerosis in Youth (PDAY). The lipid measures included HDL cholesterol (HDL-C) and non-HDL-C, and the apolipoprotein measures included concentrations of apoA1, apoB, and Lp(a), and sizes of the apo(a) proteins. We tested whether the apolipoprotein measures predicted atherosclerotic lesions as well as the more traditional lipid measures. We estimated extent of lesions as fatty streaks or raised lesions (fibrous plaques, complicated or calcified lesions) in 3 sites: thoracic aorta, abdominal aorta, and right coronary artery. Neither apoA1 nor apoB measures were as strongly or consistently correlated with extent of lesions as the corresponding lipid measure (HDL-C and non-HDL-C, respectively). Beyond the basic model that included sex, age, race, smoking status, hypertension, and the lipid measures, apoA1 and apoB added only an average 1.3% increased explanatory ability to the model, whereas HDL-C plus non-HDL-C added an average 2.5%. The results suggest that the traditional lipid measures are more useful than apolipoprotein measures for detecting young persons at high risk of precocious atherosclerosis. Because of large racial differences, the two Lp(a)-related measures, Lp(a) concentrations and apo(a) size, were evaluated in blacks and whites separately. Under these circumstances, neither of the Lp(a)-related measures was strongly or consistently correlated with extent of lesions.

Five percent of live-born human offspring will have a genetic disorder. Of these, 20% are because of germ-line de novo mutations. Several genetic diseases, such as neurofibromatosis and Duchenne muscular dystrophy, are associated with a high percentage of de novo germ-line mutations. Until recently, a direct analysis of spontaneous mutation frequencies in mammalian germ cells has been prevented by technical limitations. We have measured spontaneous mutation frequencies in a lacI transgene by using enriched populations of specific spermatogenic cell types. Similar to previously published results, we observed a lower mutation frequency for seminiferous tubule cell preparations, which contain all stages of spermatogenesis, relative to somatic tissues. We made the unexpected observation of a decline in mutation frequency during spermatogenesis, such that the mutation frequencies of type B spermatogonia and all subsequent stages of spermatogenesis are lower than the frequency for primitive type A spermatogonia. In addition, spermatogenic cells from old mice have significantly increased mutation frequencies compared with spermatogenic cells from young or middle-aged mice. Finally, the mutation frequency was observed to increase during spermiogenesis in postreplicative cell types when spermatogenic cells were obtained from old mice.

In a cooperative multicenter study, the Pathobiological Determinants of Atherosclerosis in Youth, we measured atherosclerosis of the aorta and right coronary artery (RCA) in 2403 black and white men and women 15 through 34 years of age who died of external causes and were autopsied in forensic laboratories. We measured the diameter of the opened, flattened, and fixed RCA and the diameter, intimal thickness, intimal cross-sectional area, medial thickness, and medial cross-sectional area of the pressure-perfused, fixed left anterior descending (LAD) coronary artery. Using the ratio of intimal thickness to outer diameter of the small renal arteries to predict mean arterial pressure during life, we classified the cases as normotensive (mean arterial pressure < 110 mm Hg) or hypertensive (mean arterial pressure > or = 110 mm Hg). The prevalence of hypertension by age, sex, and race corresponded closely with that measured in a survey of the living population. Hypertension had little or no effect on fatty streaks. Hypertension was associated with more extensive raised lesions in the abdominal aortas and RCAs of blacks > 20 years of age and in the RCAs of whites > 25 years of age. At all ages, women had less extensive raised lesions in the RCAs than did men, but the effect of hypertension on raised lesions was similar to that in men. Adjustment for serum lipoprotein cholesterol levels and smoking in a subset of cases yielded results similar to those obtained without adjustment. Hypertension was associated with larger diameters of the RCA and LAD coronary artery and with larger cross-sectional intimal and medial areas of the LAD coronary artery. Hypertension augments atherosclerosis in both men and women primarily by accelerating the conversion of fatty streaks to raised lesions beginning in the third decade of life, and the effect of hypertension increases with age.

Rationale and Objectives: Prospective studies of radiologists' interpretations of selected radiographs reported 20-40 years ago indicated error rates of 30% and higher. The authors retrospectively evaluated the interpretations of groups of radiologists and determined a range of rates of disagreement in interpretation. Quality assessment or recredentialing may add to the importance of such studies in the future., Materials and Methods: Over a 7-year period, a team of radiologists reviewed imaging interpretations in the radiology departments of six community hospitals. Each review, which lasted about 3 days, included evaluation of the interpretations of a 3%-4% sample of the images read by the radiologists at these hospitals. Reading errors were quantitated and evaluated qualitatively., Results: In a review of over 11,000 images read by 35 radiologists, the authors found a 4.4% mean rate of interpretation disagreement; only one radiologist had a mean rate above 8%. Qualitative analysis of the interpretation errors revealed a mean rate of 3.0% of errors that were considered to be below an acceptable standard of care. Radiologists whose errors included a relatively high proportion of false-positive findings tended to make relatively fewer total errors., Conclusion: Rates of disagreement for a broad range of studies that radiologists interpret in a community hospital setting appear to be far lower than earlier studies on selective radiographs indicated.

Unlabelled: The phenomenon of accelerated gastric emptying has been previously reported in two conditions that are considered to be part of the insulin-resistance syndrome: namely, noninsulin-dependent diabetes (NIDDM) and increased body mass index (BMI). No previous studies have assessed the rate of gastric emptying in patients with essential hypertension, another disease considered to be part of the insulin-resistance syndrome., Methods: Scintigraphic gastric emptying studies were performed on nine hypertensive subjects and on nine sex-, age-, ethnicity and BMI-matched controls., Results: Subjects with hypertension had significantly more rapid gastric half-emptying times (gastric T50) (40.0 +/- 6.9 min versus 56.6 +/- 3.7 min, p = 0.02) than controls. There was an inverse relationship between average glucose during the first 30 min and 60 min of the oral glucose tolerance test with the gastric half-emptying time (Spearman rank correlation coefficient rs = -0.64, p = 0.0045 and rs = -0.48, p = 0.0428, respectively)., Conclusion: The occurrence of accelerated gastric emptying in hypertensive subjects, in addition to that previously reported in subjects with NIDDM or increased BMI, suggests the possibility that accelerated gastric emptying may be a common finding in insulin resistant states.

Atherosclerosis begins in childhood and progresses from fatty streaks to raised lesions in adolescence and young adulthood. A cooperative multicenter study (Pathobiological Determinants of Atherosclerosis in Youth [PDAY]) examined the relation of risk factors for adult coronary heart disease to atherosclerosis in 1079 men and 364 women 15 through 34 years of age, both black and white, who died of external causes and were autopsied in forensic laboratories. We quantitated atherosclerosis of the aorta and right coronary artery as the extent of intimal surface involved by fatty streaks and raised lesions and analyzed postmorterm serum for lipoprotein cholesterol and thiocyanate (as an indicator of smoking). The extent of intimal surface involved with both fatty streaks and raised lesions increased with age in all arterial segments of all sex and race groups. Women had a greater extent of fatty streaks in the abdominal aorta than men, but women and men had about an equal extent of raised lesions. Women and men had a comparable extent of fatty streaks in the right coronary artery, but women had about half the extent of raised lesions. Blacks had a greater extent of fatty streaks than whites, but blacks and whites had a similar extent of raised lesions. VLDL plus LDL cholesterol concentration was associated positively and HDL cholesterol was associated negatively with the extent of fatty streaks and raised lesions in the aorta and right coronary artery. Smoking was associated with more extensive fatty streaks and raised lesions in the abdominal aorta. All three risk factors affected atherosclerosis to about the same degree in both sexes and both races. Primary prevention of atherosclerosis by controlling these adult coronary heart disease risk factors is applicable to young men and women and to young blacks and whites.

In a cooperative multicenter study, Pathobiological Determinants of Atherosclerosis in Youth, of 1164 young men 15 through 34 years of age who died of external causes and were autopsied in forensic laboratories, we measured atherosclerosis of the aorta and the right coronary artery. Using the ratio of intimal thickness to outer diameter of the small renal arteries to predict mean arterial pressure (MAP) during life, we classified the cases as either normotensive (MAP < 110 mm Hg) or hypertensive (MAP > or = 110 mm Hg). By this criterion, the prevalence of hypertension in blacks was 16%; in whites, 12%. Hypertension was associated directly with blood level of glycohemoglobin (an indicator of blood glucose concentration) and with body mass index (BMI) but inversely with thickness of the panniculus adiposus. Among hypertensive compared with normotensive cases, the extent of raised lesions (mainly fibrous plaques) was greater in the aortas of 30- to 34-year-old men and in the right coronary arteries of 25- to 34-year-old men. The prevalence of raised lesions involving 5% or more of the intimal surface was twofold greater in the aortas and right coronary arteries of hypertensive men throughout the 15-to-34-year age span of the study cases. The association of hypertension with raised lesions was not accounted for by adjusting for glycohemoglobin level, BMI, or thickness of the panniculus adiposus. Hypertension is associated with accelerated atherosclerosis in youth.

In a cooperative multicenter study (Pathobiological Determinants of Atherosclerosis in Youth, PDAY) of 1532 young persons 15 through 34 years of age who died of external causes and were autopsied in medical examiners' laboratories, we quantified atherosclerosis of the aorta and the right coronary artery. We analyzed postmortem blood cells for glycohemoglobin and postmortem serum for lipoprotein cholesterol and thiocyanate (as an indicator for smoking). We measured the thickness of the panniculus adiposus and the body mass index (weight per height squared) as indicators of adiposity. Glycohemoglobin levels exceeding 8% were associated with substantially more extensive fatty streaks and raised lesions in the right coronary artery in persons more than 25 years of age and with more extensive raised lesions in the aorta in persons more than 30 years of age. Both thickness of the panniculus adiposus and body mass index were associated with more extensive fatty streaks and raised lesions in the right coronary artery. The associations of atherosclerotic lesions with glycohemoglobin and adiposity were not explained by a less favorable lipoprotein profile or smoking. The results show that atherosclerosis in young adults is associated with the prediabetic or early diabetic state, as indicated by elevated glycohemoglobin levels, and with obesity.

We estimated the effects of breast- and formula-feeding on cholesterol and bile acid metabolism for 1.5 years after weaning in 35 newborn baboons that were breast-fed (n = 12) or fed one of two formulas with high (n = 11) or low (n = 12) polyunsaturated/saturated (P/S) fatty acid composition. Infants were weaned at 15 weeks to a high cholesterol, saturated fat diet. Because formula P/S ratio did not affect any variable for 1.5 years after weaning, the data were averaged for the two formula groups. After weaning, serum cholesterol and lipoprotein cholesterol concentrations among the infant diet groups were not different until after 52 weeks of age. From 70 to 97 weeks of age, serum cholesterol and high density lipoprotein-2 (HDL2)-cholesterol (HDL2-C) concentrations were lower (P < 0.04) among baboons that were breast-fed as infants compared with those fed formulas. We observed no significant postweaning differences in low density lipoprotein (LDL)-C, HDL3-C, or serum apolipoprotein A-I, B, or E concentrations. At 97 weeks of age baboons that were breast-fed until 15 weeks compared with those formula-fed had a 25% lower total bile acid synthetic rate (36.6 vs. 48.6 mumol/day per kg body weight, P < 0.02) due principally to a 29% lower cholic acid synthetic rate (23.2 vs 32.5 mumol/day per kg body weight, P < 0.004). Baboons breast-fed as infants had a 44% higher hepatic LDL-receptor mRNA concentration than those formula-fed (1.45 vs. 1.01 pg mRNA/micrograms total RNA, P < 0.003).(ABSTRACT TRUNCATED AT 250 WORDS)

We investigated common length polymorphisms in the hypervariable region located 3' to the human gene encoding apolipoprotein B (APOB 3' HVR) as part of the "Pathobiological Determinants of Atherosclerosis in Youth (PDAY)" study. PDAY is a multicenter study of young persons who died of external causes (accident, homicide, and suicide). The APOB 3' HVR contains multiple copies of AT-rich tandem repeats (15bp) called hypervariable elements (HVE). Using polymerase chain reaction (PCR) to amplify APOB sequences in hepatic DNA samples, we identified 22 different HVR alleles among 232 PDAY cases. In addition to 14 previously identified alleles, we detected 8 new alleles that had not been observed in population surveys. Of these new alleles, 7 were present only in black cases. We also examined distributions of HVR allele frequencies for blacks and whites. The frequency distributions for whites did not differ from those from previous studies of French populations (P = 0.3811) and Austrian populations (P = 0.1885). In contrast, the allele frequency distribution for blacks differed from whites (P < 0.001). Blacks had higher frequencies of smaller alleles (< or = 33 repeats) and larger alleles (> or = 37 repeats) than whites. We also sequenced specific HVR alleles to identify differences responsible for size variation. The most frequent alleles were identical in sequence to HVR alleles described in previous studies. However, one allele was not identical in sequence to an equivalent-sized allele from a previous study. In all likelihood, detection of sequence substitutions in the APOB 3' HVR would result in an even greater amount of allelic variability than detected by size differences alone.

Investigators in eight communities collected aortas, right coronary arteries, blood and liver samples, and associated information from 872 young males, aged 15-34 years, who died of external causes. Pathologists graded the arteries for atherosclerotic lesions, and a central laboratory measured lipoprotein cholesterol concentrations. Apolipoprotein (apo) B sequences were amplified in hepatic DNA samples to determine genotypes for length polymorphisms in the signal peptide of apo B. In addition to the insertion (ins) allele (27-amino acid signal peptide) and the deletion (del) allele (24 amino acids), we detected a rare allele (ins*) in whites with an in-frame insertion of two Leu codons in a region that normally contains six Leu codons. The frequency for the apo B del allele was lower in blacks than in whites (p less than 0.0001). In blacks, homozygotes for the ins allele had the lowest levels of serum cholesterol and very low plus low density lipoprotein cholesterol (VLDL + LDL-C), homozygotes for the del allele had the highest levels, and heterozygotes had intermediate levels (p = 0.0509 for cholesterol, p = 0.0530 for VLDL + LDL-C), but no differences were found in whites. In blacks, homozygotes for the ins allele had the least involvement of the thoracic and the abdominal aorta with lesions, homozygotes for the del allele had the greatest involvement, and heterozygotes had intermediate involvement (p = 0.0328 for thoracic aorta, p = 0.0104 for abdominal aorta), but no differences were found in whites.(ABSTRACT TRUNCATED AT 250 WORDS)

Gastric emptying of a liquid glucose meal was measured with scintigraphic techniques in nine recently diagnosed Type 2 diabetic patients and nine sex- and age-matched nondiabetic control subjects. Seven of the nine Type 2 diabetic patients were receiving oral hypoglycemic therapy which was discontinued the evening prior to the study. The other two diabetic patients were taking no medication. The average gastric half-emptying time was 33.6 min (s.e.m. = 3.2) for the diabetic patients and 64.6 min (s.e.m. = 4.2) for the nondiabetic controls (p = 0.0005). These measurements indicate rapid gastric emptying in Type 2 diabetic patients which may contribute to worsening of glucose control in these patients.

We performed a total of 12 gastric emptying studies on 6 normal subjects with a hyperosmolar (1.85 mol/l) 400-kcal glucose solution commonly used for diagnosing diabetes and a more dilute (0.62 mol/l) 200-kcal glucose solution. The gastric half-emptying time was greatly prolonged with both glucose solutions; 107 min for the (1.85 mol/l) 400-kcal glucose solution compared to 66 min for the more dilute (0.62 mol/l) 200-kcal glucose solution. Although the 200-kcal glucose solution contained one-half the amount of glucose (50 g) compared to the 400-kcal solution (100 g), the blood glucose values obtained during a 2-hr period were only slightly lower with the former solution. This study demonstrates significantly delayed gastric emptying of glucose solutions in normal subjects and a linear pattern of gastric emptying formerly associated only with solid meals.

We present an estimator of the probability density of capillary diameters based on a simple probabilistic model of microsphere passage through a microvascular bed. With this model, an estimate of the density is obtained as the solution of an integral equation. The density is approximated by a linear combination of B-splines with the coefficients restricted to be nonnegative. Equations for maximum likelihood estimates of the coefficients are obtained. The proposed method is applied to data from the dog intestinal circulation.

Using the baboon as a model, we tested the hypothesis that preweaning food intake influences the number of adipocytes at weaning. Two groups of 12 newborn baboons each were fed either a concentrated or a diluted Similac formula from birth to 18 weeks of age. Baboons fed the concentrated Similac were 38% heavier (P less than 0.01) and had 87% more fat mass (P less than 0.01) than the baboons fed diluted Similac. The mean adipocyte volume and adipocyte number were measured directly in 10 individual fat depots, and the total number of adipocytes were estimated for each baboon. The difference in fat mass was due to differences (P less than 0.01) in mean adipocyte volume, which was 0.22 nl in overfed baboons and 0.09 nl in underfed baboons. There was no significant diet effect on the estimated total number of fat cells; nor on 8 of 10 depots in which adipocyte number was directly measured. These results indicate that, in baboons, preweaning caloric intake has little or no influence on the number of fat cells at the age of weaning.

We examined the relationship of hypertension and plasma renin activity to atherogenesis in 48 moderately hyperlipidemic (total serum cholesterol was about 200 mg/dl) baboons (Papio sp.). We used renal artery stenosis (two-kidney, one clip model) to produce hypertension associated with elevated plasma renin activity, and used cellophane wrapping of both kidneys (bilateral perinephritis model) to produce hypertension with normal renin activity. Renal artery stenosis and bilateral perinephritis increased both systolic and diastolic blood pressure by about 30 mm Hg. Renal artery stenosis approximately doubled, but bilateral perinephritis did not change plasma renin activity. Both hypertensive groups, to about the same degree, had significantly more extensive atherosclerosis than the control group in the abdominal aorta and brachial, iliac-femoral, and carotid arteries. The effect of hypertension was greatest in the carotid arteries where the extent of atherosclerosis was nearly tripled. Hypertension did not influence lesions in the thoracic aorta. By multiple regression analysis, very low plus low density lipoprotein cholesterol, high density lipoprotein cholesterol, and systolic blood pressure were consistently strong predictive variables for the extent of atherosclerotic lesions. Most of the effects of renal hypertension on atherosclerotic lesions appeared to be accounted for by the increase in blood pressure. In the carotid arteries, however, there was a suggestion of an effect above that due to increased blood pressure. Additional analyses indicated that these treatment effects were associated with serum potassium concentration, plasma renin activity, or other closely related variables.

For 26 months, we fed baboons a high saturated fat, high cholesterol diet that contained very low concentrations of four common pesticides (chlordane, parathion, diazinon, and carbofuran). We detected no effect of pesticides on body weight, serum lipid, or lipoprotein cholesterol concentrations, or experimental atherosclerosis. We then examined the associations of serum lipid and lipoprotein cholesterol concentrations (predictor variables) with arterial lesions (response variables). Among predictor variables, very low density lipoprotein plus low density lipoprotein cholesterol concentration showed a positive association with fatty streaks in the aorta and its major branches, including the coronary arteries, while high density lipoprotein cholesterol concentration showed a consistently negative association. The very low density lipoprotein plus low density lipoprotein/high density lipoprotein cholesterol ratio was more highly associated with lesions than was either value alone. These results are consistent with epidemiologic evidence suggesting that high density lipoprotein cholesterol concentration is inversely related to probability of developing clinically manifest atherosclerotic disease.

Some progeny of baboons (Papio sp.) selectively bred for a high response of serum cholesterol to an atherogenic diet have high serum levels of unusual lipoproteins with flotation rates of F degrees 1.20 9-28, intermediate between those of low and high density lipoproteins (HDL). They are similar to the fraction of HDL commonly called HDL1. We conducted a cross-over experiment to determine the roles of dietary cholesterol and saturated fat in eliciting these lipoproteins in the progeny of two affected sires. Half of the progeny of each sire manifested the trait (high HDL1 phenotype) while consuming an atherogenic diet and half did not (low HDL1 phenotype). While consuming a chow diet, high HDL1 progeny had higher total serum cholesterol concentrations than did low HDL1 progeny. This difference was exaggerated when the animals consumed diets enriched in either cholesterol or saturated fat (lard), and was greatest when the diet contained both. High HDL1 animals also had considerably higher serum apo E concentrations, and slightly higher serum apo A-I concentrations. High HDL1 progeny had much higher levels of cholesterol (twofold) and of apo A-I (three- to eightfold) in HDL1 fractions than did low HDL1 progeny. There were significant interactions between HDL1 class and both dietary cholesterol and saturated fat in their effects on other lipoprotein fractions. High HDL1 animals had an exaggerated elevation of cholesterol and apo B in very low, intermediate, and low density lipoproteins in response to dietary cholesterol. They also had an exaggerated elevation of cholesterol in the lighter HDL1 fraction (d = 1.041-1.053), and lesser elevation of cholesterol and apo A-I in HDL2.

We examined the effects of breast and formula feeding during infancy on the serum lipoproteins and on atherosclerosis in young adult baboons. Baboons were breast-fed (n = 13) or formula-fed (n = 32) until weaning at 16 weeks of age and thereafter they were fed a diet containing 1.7 mg cholesterol/kcal and 40% of calories as lard until 5 years of age. At 12 weeks of age, breast-fed baboons had higher serum high density lipoprotein cholesterol concentration (HDL-C, 68 vs. 51 mg/dl), lower serum triglyceride concentration (37 vs. 68 mg/dl), and lower very low density plus low density lipoprotein cholesterol (VLDL + LDL-C) to HDL-C ratio (0.65 vs. 0.98) than formula-fed infants. From weaning to 92 weeks of age, breast-fed baboons had a lower serum triglyceride concentration (23 vs. 38 mg/dl) than formula-fed baboons. After weaning, the VLDL + LDL-C/HDL-C ratio increased from 0.65 to 1.0 in breast-fed baboons, but decreased from 0.98 to 0.72 in formula-fed baboons. From 92 to 246 weeks of age, the VLDL + LDL-C/HDL-C ratio was consistently higher in breast-fed baboons compared to formula-fed baboons. At 5 years of age, baboons breast-fed as infants had a greater percentage of intimal surface area involved with atherosclerosis in the abdominal aorta, the iliac-femoral artery, the aortic arch, the brachial artery, and the carotid artery, than did those formula-fed as infants. The greater prevalence of lesions in breast-fed baboons was explained mainly by the higher VLDL + LDL-C/HDL-C ratio.

Positive assortative mating of baboons (Papio sp.) based on elevation of serum cholesterol concentrations in response to a cholesterol- and saturated fat-enriched diet produced 64 progeny (30 high line; 34 low line). When the animals were 3 to 4 years of age, we tested their lipoprotein cholesterol responses to dietary cholesterol and fat in a factorial experiment with two levels of dietary cholesterol (1.7 and less than 0.01 mg/kcal) and two types of fat, coconut oil (P/S 0.1) and corn oil (P/S 3.5), each providing 40% of total calories from fat; we also tested their responses to chow. The high line animals had significantly higher very low density plus low density lipoprotein (VLDL + LDL) and high density lipoprotein (HDL) cholesterol levels on all diets. The effects of dietary cholesterol on VLDL + LDL cholesterol concentrations were greater in high line animals than in low line animals, but dietary cholesterol's effects on HDL cholesterol were similar in both lines. The effects of saturated fat, compared to unsaturated fat, on both VLDL + LDL and HDL cholesterol levels were similar in both lines. Selective breeding produced lines diverging in lipoprotein cholesterol concentrations by acting on several different genetically mediated processes that control serum lipoprotein levels. At least one of these processes involves responsiveness of serum VLDL + LDL cholesterol concentration to dietary cholesterol.

The hypothesis that energy intake influences differently the composition of mass gain during the preweaning period was tested in male and female baboons. Infant baboons were fed either a high (92 kcal/100 g formula) or a low (49 kcal/100 g formula) caloric formula from birth. Body mass, lean body mass and fat mass of each baboon were measured directly at weaning (18 weeks of age). Lean mass and fat mass gained from birth to 18 weeks was estimated by using body composition data from eight newborn baboons. Both energy intake and gender significantly influenced gain of total mass, lean mass and fat mass. There was a significant gender by diet interaction effect on the gain of fat mass. When fed the high caloric formula, males gained 145 g more lean mass than females, but the increase of fat mass was approximately the same. In contrast, on the low caloric formula, males gained 150 g more lean mass than females but 74 g less fat mass than females. These results indicate that fundamental differences in the development of lean mass and fat mass exist between male and female baboons during preweaning life.

We examined the effects of dietary cholesterol (less than 0.01 and 1.7 mg/Kcal) and type of fat (saturated, coconut oil; polysaturated, corn oil) on very low density plus low density lipoprotein (VLDL + LDL) and high density lipoprotein (HDL) cholesterol in 24 young baboons (12 male, 12 female) Paplo sp.) in a crossover design experiment. The oils contributed 40% of calories. Total serum cholesterol concentration on the low cholesterol-polyunsaturated fat diet averaged 120 mg/dl; on the high cholesterol-saturated fat diet, 245 mg/dl; and on the other two cholesterol-fat diet combinations, about 200 mg/dl. There was a significant interaction between cholesterol and type of fat in their effects on VLDL + LDL cholesterol, but not in their effects on HDL cholesterol. Dietary cholesterol elevated VLDL + LDL cholesterol when fed with both types of fat, but elevated it more when fed with polyunsaturated fat than with saturated fat. Saturated fat elevated VLDL + LDL cholesterol when dietary cholesterol was low, but not when dietary cholesterol was high. Saturated fat consistently elevated HDL cholesterol more than did dietary cholesterol. The response of apolipoprotein B concentrations to dietary components was similar to that of VLDL + LDL cholesterol. These results indicate that dietary cholesterol and type of fat have different effects on the distribution of cholesterol among the major serum lipoproteins of the baboon.

Thirty-six young adult male baboons (Papio cynocephalus) were fed an atherogenic diet (40% calories from lard, 1.5 mg cholesterol/kcal) and taught to puff by operant conditioning with water rewards. Eighteen baboons (smokers) were assigned randomly to smoke 43 cigarettes a day, and 18 baboons (shams) were assigned randomly to puff air under conditions equivalent to those of the experimental group. During months 14-19 of smoking, cigarette-smoking baboons had significantly higher carbon monoxide and thiocyanate concentrations in blood and cotinine concentrations in urine. There were no significant differences in serum total cholesterol, VLDL + LDL cholesterol, HDL cholesterol or triglyceride concentrations of smokers and shams. Smoking baboons had significantly higher fasting blood glucose concentrations and lymphocyte counts. Platelet count, platelet aggregation, food and water intake, and body weight were not significantly different in the two groups.