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The human DNA mismatch repair gene homologue hMSH2, on chromosome 2p is involved in hereditary non-polyposis colon cancer (HNPCC). On the basis of linkage data, a second HNPCC locus was assigned to chromosome 3p21-23 (ref. 3). Here we report that a human gene encoding a protein, hMLH1 (human MutL homologue), homologous to the bacterial DNA mismatch repair protein MutL, is located on human chromosome 3p21.3-23. We propose that hMLH1 is the HNPCC gene located on 3p because of the similarity of the hMLH1 gene product to the yeast DNA mismatch repair protein, MLH1, the coincident location of the hMLH1 gene and the HNPCC locus on chromosome 3, and hMLH1 missense mutations in affected individuals from a chromosome 3-linked HNPCC family.

Although Heiderian logic (F. Heider, 1958) proposes an inverse relationship between ability and effort, research has uncovered dramatic individual differences in the judged relationship between the two. Some view ability and effort as positively related; others view them as negatively related. Study 1 explored dysphoria as a moderator of this relationship by gathering dysphoric and nondysphoric individuals' perceptions of their effort and ability on daily activities. Although ability and effort generally were positively related, dysphorics reported lower ability on high effort tasks. In Study 2, Ss rated their effort as high or low. Dysphorics discounted ability when effort was high; nondysphorics reported the greatest ability when they expended the greatest effort. Collectively, there was no support for an inverse relationship between ability and effort. However, dysphorics infer less ability than nondysphorics following high effort.

The rat-tailed sea cucumber, Paracaudina chilensis, has abundant hemoglobin-filled hemocytes in its perivisceral coelom, water vascular system, and hemal system. The perivisceral oxyhemoglobin consisted of 34 kDa dimers and molecules with an apparent molecular weight of ca. 50 kDa. The perivisceral hemoglobin had a high oxygen affinity with a P50 of 1.5 mm Hg at 15°C. It exhibited cooperative oxygen binding with a Hill coefficient of 1.26 to 1.86. Oxygen affinity appeared to be pH dependent, but the effect was not significant. The heat of oxygenation was -11.2 kcal mol-1. At high hemoglobin concentrations, the perivisceral hemoglobin oxygen affinity was lower and the apparent pH effect and cooperativity were increased. Perivisceral and water vascular hemoglobins had spectral characteristics similar to those of other invertebrate and vertebrate hemoglobins. The perivisceral hemoglobin appeared to be electrophoretically heterogeneous and was structurally distinguishable from water vascular hemoglobin. The oxygen affinity of water vascular hemoglobin was not different from that of the perivisceral hemoglobin in spite of the difference in structure and location in the animal. The exceptionally high oxygen affinity hemoglobin of P. chilensis, a burrowing sea cucumber, may be adaptive to this animal's oxygen-limited habitat.

Objective: Sonographic visualization of ureteral jets is a well-recognized phenomenon. In vitro studies have indicated that detection of fluid flow similar to ureteral jets depends on differences in density between the moving and the stationary fluid. This study was undertaken to determine if differences in density between ureteral urine and urine in the bladder could make a significant impact on the sonographic detectability of ureteral jets in vivo., Subjects and Methods: Ten healthy volunteers were vigorously hydrated after an overnight fast. An initial color Doppler sonographic examination of ureteral jets was performed before voiding (while concentrated urine that had accumulated overnight was still in the bladder). A second examination was performed after two cycles of voiding and refilling the bladder (to ensure that dilute urine produced by the hydration was in the bladder)., Results: In all subjects, normal ureteral jets were readily identified on the initial examination. The difference in the estimated specific gravity between bladder urine and ureteral urine during the initial examination ranged from 0.002 to 0.016 (mean, 0.008). This was a statistically significant difference (p less than .05). On the second examination, ureteral jets were not detected from either ureter in any subject. The difference in the estimated specific gravity of bladder urine and ureteral urine during the second examination ranged from 0.000 to 0.002 (mean, 0.001). This was not a statistically significant difference (p greater than .05). There was no statistically significant difference in the diuresis rates throughout the course of the examinations. These ranged from 300 to 1218 ml/hr., Conclusion: These in vivo results support the hypothesis that detection of ureteral jets depends on density differences between ureteral and bladder urine. This is important clinically, because normal ureteral jets may be undetectable, despite adequate hydration and high rates of diuresis, if the patient is allowed to completely void and refill the bladder before the examination.

The effects of hypoxia (1.5 mg O2 1-1, 20% of air saturation) and anoxia (<0.07 mg O2 1-1, <1% of air saturation) on oyster (Crassostrea virginica) larval settlement, juvenile growth, and juvenile survival were studied. Settlement was reduced significantly (P < 0.05) in hypoxic treatments, as compared to normoxic treatments (7.3 mg O2 h-1, 100% of air saturation), and almost no settlement took place in anoxic treatments. After 96 h, 38% and 4% of the larvae placed in hypoxic and anoxic treatments had settled, while 79% settled in normoxic treatments. In the first 144 h after settlement, juveniles in hypoxic treatments grew one third as much as those in normoxic treatments, while juveniles in anoxic treatments did not grow at all. Median mortality times of recently settled juveniles in hypoxic and anoxic treatments were 131 h and 84 h, respectively. We conclude that hypoxic and anoxic waters have potentially detrimental effects on oyster settlement and recruitment.

We have investigated the response of the filamentous fungus Aspergillus nidulans to low, non-killing, doses of the alkylating agent MNNG (N-methyl-N'-nitro-N-nitrosoguanidine). Such treatment causes a substantial induction of DNA alkyltransferase activity, with the specific activity in treated cells increasing up to one hundred-fold. Fluorography reveals the two main inducible species as proteins of 18.5 kDa and 21 kDa, both of which have activity primarily against O6-methylguanine (O6-MeG) lesions. In addition, two other alkyltransferase proteins can also be detected. One, of MW 16 kDa, is expressed in non-treated cells, but is not induced to the same extent as the 18.5 and 21 kDa proteins. The other, a protein of 19.5 kDa, is highly inducible and can only be detected in treated cells. Unlike the other three proteins, it acts primarily against methyl-phosphotriester (Me-PT) lesions. This is the first instance in which an MePT alkyltransferase has been detected in a eukaryotic organism and, coupled with the high level of induction of the O6-MeG alkyltransferase enzymes, this indicates that a control system similar to the bacterial adaptive response may be present in filamentous fungi.

Diagnostic categories that are useful for describing patients with acute or organ failure disease are generally less useful labels for primary care and preventive medicine patients whose conditions are better described by signs and symptoms. Symptoms may be clues to ill health but are not often criteria for a major diagnostic labeling. In my practice I have used a computer-based medical record system that permits portrayal and comparison of symptom data to correlate varying degrees of retention of an intramuscular magnesium-loading study (IMMLS) with symptom patterns in 172 patients. The group of patients who show a paradoxical excretion of more Mg than they were given in the IMMLS are a distinctive group with lower blood pressures and significantly fewer digestive and skin symptoms, fewer symptoms of inflammation but more emotional symptoms than those with normal Mg excretion. The group who retained > 49% of the load had higher blood pressures and significantly fewer symptoms of inflammation of the skin and of the reproductive tract.

We used a combination of cloned DNA fragments encoding the GAL7 gene, yeast plasmid vectors, and chromosomal gal7 deletions to characterize the in vivo transcription of the GAL7 gene on autonomously replicating plasmids. Our results demonstrated that a plasmid-borne 3.1-kilobase DNA fragment containing the GAL7 gene provides sufficient information to mimic the regulated expression of the chromosomal location. Normal expression of GAL7 could occur in the absence of DNA encoding the functional genes of the GAL cluster region and was not altered when the gene was adjacent to other plasmid elements such as autonomously replicating sequences or centromeres. The chromosomal and single-copy centromeric plasmid locations of GAL7 were indistinguishable in their response to growth conditions (induction by galactose, repression by glucose) and positive and negative regulatory factors (GAL4 and GAL80). Increasing the gene dosage to more than 200 copies per cell resulted in constitutive expression of the GAL7 mRNA; fully induced mRNA levels were increased more than 10-fold at these high gene dosages. When cells were shifted from noninducing to inducing conditions, the initial time of appearance and the rate of accumulation of GAL7 mRNA were altered in cell populations containing multiple GAL7 genes. The induction kinetics and final accumulation of the chromosomal GAL10 mRNA were also affected by the presence of multiple copies of the GAL7 gene; these results are consistent with a model involving limiting amounts of regulatory factors.

Collaboration between pediatricians and mental health clinicians in an HMO has provided a useful method of identifying and caring for the usual spectrum of developmental and situational disturbances in children and the associated parent-child conflicts. A social worker is included in the primary-care team in pediatrics; other mental health resources are available when indicated. In 1974, 5.7% of total visits and 8.9% of all children under 19 years of age were noted to have emotional problems. A follow-up study carried out early in 1976 disclosed that most of the observed emotional problems were resolved or quiescent.

A follow-up study was conducted on 131 foals that were less than 7 days old when admitted to the University of Florida Veterinary Medical Teaching Hospital between 1981 and 1983. Of the 71 foals (54%) that survived to be discharged, 39 (55%) were alive at follow-up evaluation, 19 (27%) could not be located, and 13 (18%) had died. The owners of surviving foals were sent questionnaires and 72% responded. The horses were visited and examined, if geographically possible, and an age-matched stablemate or a sibling also was evaluated and used as a control. Thirteen foals (10% of total admitted) died 1 day to 2 years after discharge. Four (8%) died from suspected sequelae of their neonatal illness. Three other foals appeared stunted as yearlings, but by 2 years of age equaled or passed their stablemates and/or siblings in physical development. The owners' estimated value of the survivors averaged +29,812. The actual selling price of horses that went through sales ranged from +7,000 to +210,000. Most of the horses became useful, athletic adults; several have won major stakes races. All living foals appeared unaffected by the physiologic disorders and treatments they encountered as neonates and compared favorably with stablemates and siblings.

Idiopathic mitral valve prolapse (MVP) is the commonest valvular disorder in industrialized nations. It is predominantly a familial condition, showing Mendelian dominance with delayed and variable penetrance. Although hyperkinesis and hypertrophy of the left ventricle have been described in MVP, its histopathology, somatic morphology and genetics support the leading theory that MVP results from a hereditary disorder of connective tissue. Latent tetany (LT) due to chronic Mg deficit (Mg-D) occurs in over 85% of MVP cases; MVP complicates 26% of LT. Mg-D can explain many clinical features of the MVP syndrome which are not easily explained by its genetics. Mg-D hinders the mechanism by which fibroblasts degrade defective collagen, increases circulating catecholamines, predisposes to cardiac arrhythmias, thromboembolic phenomena and dysregulation of the immune and autonomic nervous systems. Mg therapy provides relief of MVP symptoms.

Studies on the lung retention of polycyclic aromatic hydrocarbons (PAH) after inhalation have indicated that, in general, the PAH are rapidly cleared from the respiratory tract. Clearance of the PAH from the lungs is best described as bi-phasic, with the long-term component of the clearance curve having a half-time of greater than 24 h. The purpose of this study was to determine whether a relationship exists between the lipophilicity (as measured by the octanol/water partition coefficient, P) of various PAH and the short-term and long-term clearance half-times of PAH in rat lungs. Female F344/Crl rats were administered intratracheally 1 nmol of 14C-labelled anthracene (AN), benz[a]anthracene (BA), 1-nitropyrene (NP), 6-nitrobenzo[a]pyrene (6-NBP), or dibenzo[c,g]carbazole (DBC). At various times after instillation rats were sacrificed and the amount of 14C remaining in the lungs was determined. Octanol/water partition coefficients were experimentally determined for each of the PAH used. Clearance of 14C from rat lungs following instillation of the different PAH was biphasic. In all cases, greater than 85% of the initial dose instilled was cleared with a half-time of less than 1 h. The half-times for clearance of the residual 14C (1-15% of the dose) were 26, 30, 36, 53 and 63 h for AN, NP, 6-NBP, BA and DBC, respectively. The log of the octanol/water partition coefficients for the different PAH examined ranged from 4.1 (AN) to 6.05 (DBC). Plots of the octanol/water coefficients vs. the long-term clearance half-time for the PAH indicated a linear correlation (p less than 0.001; r2 = 0.96). The results from this study indicate that the greater the lipophilicity of the PAH, the slower the long-term clearance of a small fraction (1-15%) of PAH from rat lungs. These data suggest that predictions of long-term lung clearance can be made for PAH with log octanol/water partition coefficients between 4 and 6.

High levels of the GAL7 gene in the yeast cell appear to titrate regulatory factors and to impair transcription of related sequences. To investigate the role that the GAL regulatory factors GAL4 and GAL80 have in this process we have compared the accumulation of mRNA transcribed from single-copy (plasmid-borne GAL7 and chromosomal GAL10) and high-copy (plasmid-borne GAL7) genes in several GAL regulatory mutants. Our results show that functional GAL4 gene product is required for induction of transcription from the single- and high-copy genes. In a strain containing the GAL4 gene fused to the high expression ADH1 promoter, glucose can replace galactose to induce high levels of transcription of GAL7 and GAL10 genes, although the kinetics of accumulation induced by the two sugars are distinctly different. In the presence of high levels of GAL4, maximum accumulation of mRNA from single and high copy genes is elevated two-fold; disruption of the gal80 gene in combination with high levels of GAL4 results in a further two-fold increase in transcription. In this genetic background, galactose-induced transcription of the high copy GAL7 gene results in a greater than 50-fold increase in the levels of GAL7 mRNA, representing 30%-50% of the total cellular mRNA. Our results are consistent with a cooperative effect of saturation of multiple GAL4 DNA binding sites and with a limiting factor, in addition to GAL4, that is required for transcription of the GAL genes.

We have cloned an 82-base-pair region spanning the site of normal 3' end formation of Saccharomyces cerevisiae CYC1 mRNA into an integrative vector carrying the 5' end of the actin gene (including its intron) fused in frame to HIS4ABC sequences. This vector can confer the ability to grow on histidinol if HIS4C (encoding histidinol dehydrogenase) is sufficiently expressed. With the CYC1 fragment cloned in its wild-type (forward) orientation within the actin intron, transformants cannot grow on histidinol, whereas cells transformed with the vector carrying the reverse orientation of this fragment are able to grow well. RNA transfers demonstrate that transformants containing the forward orientation accumulate less than 40% of the control level of full-length mRNA and reveal the presence of a short, stable (approximately equal to 300 nucleotides) poly(A) RNA that represents 60-70% of the transcripts originating from the same promoter. The reverse orientation of the insert allows near-normal levels of full-length mRNA. Mapping of the 3' end of the truncated RNA indicates that poly(A) addition is variable in length but occurs at the same location as in the normal CYC1 transcript. Dominant and recessive suppressor mutations permit growth on histidinol despite the inserted fragment. Genetic analyses indicate that most of the dominant mutants are cis-acting and that the recessive mutants define a minimum of three complementation groups, indicating that defects in several different genes can restore higher levels of HIS4C expression.

The X-linked lymphoproliferative syndrome is characterized by immunodeficiency to Epstein-Barr virus (EBV) manifested by severe or fatal infectious mononucleosis and acquired immunodeficiency. We studied immune responses in six males of a well-characterized kindred with the X-linked lymphoproliferative syndrome. Two males were studied before and during acute fatal EBV infection. Both individuals demonstrated normal cellular and humoral immunity before EBV infection. During acute EBV infection, both individuals developed vigorous cytotoxic cellular responses against EBV-infected and -uninfected target cells. Anomalous killer and natural killer T cell activity was demonstrated against a variety of lymphoid cell lines, autologous fibroblasts and autologous hepatocytes. Effector cells responsible for anomalous killing reacted with a pan-T cell monoclonal antibody, and belonged to the OKT.8 T cell subset. Death in each case was caused by liver failure, but one patient developed extensive liver necrosis, whereas the other developed a massive infiltration of the liver with EBV-infected immunoblasts after aggressive immunosuppressive therapy. Immunological studies were performed on four males who had survived EBV infection years previously. They demonstrated global cellular immune defects with deficiencies of lymphocyte proliferative responses to mitogens and antigens, humoral immune deficiencies, abnormalities of regulatory T cell subsets and deficient natural killer cell activity. We propose that an aberrant immune response triggered by acute EBV infection results in unregulated anomalous killer and natural killer cell activity against EBV infected and uninfected cells. These studies suggest that global immune defects appearing in males with X-linked lymphoproliferative syndrome who survive EBV infection are epiphenomenon.

The relationship between hemophiliac immunodeficiency and exposures to factor VIII concentrate, LAV/HTLV-III retrovirus, and infection with Epstein-Barr virus and cytomegalovirus was examined. Exposure to factor VIII concentrate was significantly correlated with decreased percentages of T helper/inducer cells, decreased T helper/suppressor cell ratios, and decreased proliferative responses to plant mitogens. LAV/HTLV-III seropositivity was the primary predictor of increased percentages of HLA-DR-bearing mononuclear cells and decreased proliferative responses to pokeweed mitogen. Epstein-Barr virus and cytomegalovirus infections acted in a synergistic manner with LAV/HTLV-III to produce immunoregulatory defects. Increased percentages of T suppressor cells and decreased delayed cutaneous hypersensitivity skin test responses were observed in LAV/HTLV-III seropositive hemophiliacs infected with Epstein-Barr or cytomegalovirus. We conclude that hemophiliacs receiving commercial factor VIII concentrate experience several stepwise incremental insults to the immune system: alloantigens in factor VIII concentrate, LAV/HTLV-III infections, and herpesvirus infections.