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Actively growing Arabidopsis thaliana L. (Columbia wild type) root hairs were used to examine the interplay between cell turgor pressure and electrical properties of the cell: membrane potential, conductance, cell-to-cell coupling, and input resistance. Pressure was directly modulated using a pressure probe or indirectly by changing the extracellular osmolarity. Direct modulation of pressure in the range of 0 to about 15 x 10(5) Pa (normal turgor pressure was 6.8 +/- 2.0 x 10(5) Pa, n = 29) did not affect the membrane potential, conductance, coupling, or input resistance. Indirect modulation of turgor pressure by adding (hyperosmotic) or removing (hypo-osmotic) 200 mM mannitol/sorbitol affected the potential and conductance but not cell-to-cell coupling. Hypo-osmotic treatment depolarized the potential about 40 mV from an initial potential of about -190 mV and increased membrane conductance, consistent with an increase in anion efflux from the cell. Hyperosmotic treatment hyperpolarized the cell about 25 mV from the same initial potential and decreased conductance, consistent with a decline in cation influx. The results are likely due to the presence of an "osmo-sensor," rather than a "turgor-sensor," regulating the cell's response to osmotic stress.

1. We tested the effects on systemic haemodynamics and renal function, of inhibition of endopeptidase (EP) 24.15 (E.C. 3.4.24.15), in conscious uninephrectomized rabbits in which the activities of angiotensin converting enzyme (ACE, E.C. 3.4.15.1) and neutral endopeptidase (EP 24.11, E.C. 3.4.24.11) were already inhibited. To test the role of bradykinin B2-receptors in mediating the effects following inhibition of these enzymes, the antagonist Hoe 140 was used. 2. Hoe 140 (0.1 mg kg-1, i.v.) did not affect resting mean arterial pressure or heart rate, but antagonized the depressor effect of right atrial administration of bradykinin. The dose-response curve for bradykinin was shifted more than 1000 fold to the right for more than 4 h. Hoe 140 approximately doubled resting urine flow and increased fractional Na+ excretion from 4.2 to 6.0%; consistent with the hypothesis that it exerts a partial agonist effect on the kidney. 3. Combined inhibition of ACE (captopril; 0.25 mg kg-1 plus 0.2 mg kg-1h-1) and EP 24.11 (SCH 39370; 3 mg kg-1 plus 3 mg kg-1h-1) was followed by a sustained reduction in arterial pressure (-6 +/- 2 mmHg) and increase in heart rate (35 +/- 7 beats min-1). There was a small increase in renal blood flow (by 6.5 +/- 3.2% relative to vehicle-treatment) without a change in glomerular filtration rate, and about a 150% increase in Na+ excretion. Hoe 140 (0.1 mg kg-1, i.v.) pretreatment did not influence the renal effects of captopril and SCH 39370, although it did appear to blunt their hypotensive and tachycardic effects. 4. When EP 24.15 was inhibited with N-[1-(R,S)-carboxy-3-phenylpropyl]-Ala-Ala-Tyr-p-aminobenzoate (cFP-AAY-pAB; 5 mg kg-1 plus 3 mg kg-1h-1, i.v.) in rabbits pretreated with captopril and SCH 39370, no changes in systemic haemodynamics or renal function were observed. 5. We concluded that in conscious uninephrectomized rabbits, EP 24.15 does not play a major role in modulating renal function, at least under conditions where ACE and EP 24.11 are already inhibited. In contrast, ACE and/or EP 24.11 do modulate renal function in this model, but their influences are mediated chiefly through metabolism of peptides other than bradykinin.

Background: Older coronary patients suffer from a low functional capacity and high rates of disability. Supervised exercise programs improve aerobic capacity in middle-aged coronary patients by improving both cardiac output and peripheral extraction of oxygen. Physiological adaptations to aerobic conditioning, however, have not been well studied in older coronary patients., Methods and Results: The effect of a 3-month and a 1-year program of intense aerobic exercise was studied in 60 older coronary patients (mean age, 68 +/- 5 years) beginning 8 +/- 5 weeks after myocardial infarction or coronary bypass surgery. Outcome measures included peak aerobic capacity, cardiac output, arterio-venous oxygen difference, hyperemic calf blood flow, and skeletal muscle fiber morphometry, oxidative enzyme activity, and capillarity. Training results were compared with a sedentary, age- and diagnosis-matched control group (n = 10). Peak aerobic capacity increased in the intervention group at 3 months and at 1 year by 16% and 20%, respectively (both P < .01). Peak exercise cardiac output, hyperemic calf blood flow, and vascular conductance were unaffected by the conditioning protocol. At 3 and 12 months, arteriovenous oxygen difference at peak exercise was increased in the exercise group but not in control subjects. Histochemical analysis of skeletal muscle documented a 34% increase in capillary density and a 23% increase in succinate dehydrogenase activity after 3 months of conditioning (both P < .02). At 12 months, individual fiber area increased by 29% compared with baseline (P < .01)., Conclusions: Older coronary patients successfully improve peak aerobic capacity after 3 and 12 months of supervised aerobic conditioning compared with control subjects. The mechanism of the increase in peak aerobic capacity is associated almost exclusively with peripheral skeletal muscle adaptations, with no discernible improvements in cardiac output or calf blood flow.

1. The role of the metalloendopeptidase EC 3.4.24.15 (EP 24.15) in peptide metabolism in vivo is unknown, in part reflecting the lack of a stable enzyme inhibitor. The most commonly used inhibitor, N-[1-(R,S)-carboxy-3-phenylpropyl]-Ala-Ala-Tyr-p-aminobenzoate (cFP-AAY-pAB, Ki = 16 nM), although selective in vitro, is rapidly degraded in the circulation to cFP-Ala-Ala, an angiotensin converting enzyme (ACE) inhibitor. This metabolite is thought to be generated by neutral endopeptidase (NEP; EC 3.4.24.11), as the Ala-Tyr bond of cFP-AAY-pAB is cleaved by NEP in vitro. In the present study, we have examined the role of NEP in the metabolism of cFP-AAY-pAB in vivo, and have tested a series of inhibitor analogues, substituted at the second alanine, for both potency and stability relative to the parent compound. 2. Analogues were screened for inhibition of fluorescent substrate cleavage by recombinant rat testes EP 24.15. D-Ala or Asp substitution abolished inhibitory activity, while Val-, Ser- and Leu-substituted analogues retained activity, albeit at a reduced potency. A relative potency order of Ala (1) > Val (0.3) > Ser (0.16) > Leu (0.06) was observed. Resistance to cleavage by NEP was assessed by incubation of the analogues with rabbit kidney membranes. The parent compound was readily degraded, but the analogues were twice (Ser) and greater than 10 fold (Leu and Val) more resistant to cleavage. 3. Metabolism of cFP-AAY-pAB and the Val-substituted analogue was also examined in conscious rabbits. A bolus injection of cFP-AAY-pAB (5 mg kg-1, i.v.) significantly reduced the blood pressure response to angiotensin I, indicating ACE inhibition. Pretreatment with NEP inhibitors, SCH 39370 or phosphoramidon, slowed the loss of cFP-AAY-pAB from the plasma, but did not prevent inhibition of ACE. Injection of 1 mg kg-1 inhibitor resulted in plasma concentrations at 10 s of 23.5 microM (cFP-AAY-pAB) and 18.0 microM (cFP-AVY-pAB), which fell 100 fold over 5 min. Co-injection of 125I-labelled inhibitor revealed that 80-85% of the radioactivity had disappeared from the circulation within 5 min, and h.p.l.c. analysis demonstrated that only 25-30% of the radiolabel remained as intact inhibitor at this time. Both analogues were cleared from the circulation at the same rate, and both inhibitors blunted the pressor response to angiotensin I, indicative of ACE inhibition. 4. These results suggest that both NEP and other clearance/degradation mechanisms severely limit the usefulness of peptide-based inhibitors such as cFP-AAY-pAB. To examine further EP 24.15 function in vivo, more stable inhibitors, preferably non-peptide, must be developed, for which these peptide-based inhibitors may serve as useful molecular templates.

Objective: To determine the utility of anti-extractable nuclear antigen (anti-ENA) antibodies detected by enzyme-linked immunosorbent assay as a predictor for the diagnosis of systemic lupus erythematosus (SLE)., Methods: Among 2,185 serum samples sent for testing for antinuclear antibodies (ANA) by indirect immunofluorescence, 259 consecutive patients with positive ANA were identified. Medical charts of these patients were reviewed to assess the clinical diagnosis, with the reviewer having no knowledge of the anti-ENA result. Clinical data were abstracted for all patients, and diagnoses established using American College of Rheumatology criteria. The utility of ENA antibodies in the diagnosis of SLE was determined by univariate and multivariate analysis among all patients who were positive for ANA, patients who were positive for ANA and for anti-double-stranded DNA (anti-dsDNA), and patients who were positive for ANA and negative for anti-dsDNA. Clinical differences between SLE patients with and those without anti-ENA antibodies were assessed., Results: Anti-ENA antibodies, especially anti-Ro/SS-A, showed strong predictive diagnostic value among ANA+/anti-dsDNA- patients, but were of no utility among ANA+/anti-dsDNA+ patients. The only clinical manifestations that were more common among anti-ENA+ SLE patients were pleuritis and the use of hydroxychloroquine., Conclusion: The presence of anti-ENA antibodies, especially anti-Ro/SS-A, is a useful predictor for the diagnosis of SLE, primarily among patients attending a referral rheumatology center who are positive for ANA and negative for anti-dsDNA. No major clinical differences were noted among ANA+ SLE patients with versus those without ENA.

Background: Skin cancers are common and there has been a dramatic increase in their incidence, particularly melanoma. However, little is known about awareness of melanoma and early detection practices in the general U.S. population., Objective: In 1995, the American Academy of Dermatology increased their efforts to promote awareness of melanoma. This study was conducted to document current knowledge of melanoma and self-examination practices., Methods: In February 1995, a telephone survey was conducted in a nationally representative sample of 1001 persons at least 18 years of age (3% margin of error) that included questions on knowledge, attitudes, and practices regarding early detection of melanoma., Results: Almost 42% of those surveyed were unaware of melanoma, and only 26% of those who were aware could identify its specific signs. Most recognized at least one common risk factor for melanoma (e.g., sun exposure, fair skin). However, many did not distinguish melanoma from other skin cancers in terms of risk factors, signs of early disease, and body site distribution. The lowest measures of melanoma knowledge and attitudes were found among those who are male, nonwhite, and parents, and those with the lowest level of education and income. More than half (54%) did not conduct a self-examination. This practice was most frequently reported by women, white persons, and the elderly, as well as those with a greater knowledge of melanoma., Conclusion: Our research documents deficiencies in knowledge and practices related to early detection of melanoma in the general U.S. population and supports the need for public education about melanoma.

Background: Increasing incidence and mortality rates from cutaneous melanoma are a major public health concern. As part of a national effort to enhance early detection of melanoma/skin cancer, the American Academy of Dermatology (AAD) has sponsored an annual education and early detection program that couples provision of skin cancer information to the general public with almost 750,000 free skin cancer examinations (1985-1994)., Objective: To begin to evaluate the impact of this effort, we determined the final pathology diagnosis of persons attending the 1992-1994 programs who had a suspected melanoma at the time of examination., Methods: We directly contacted all such persons by telephone or mail and received pathology reports from those who had a subsequent biopsy., Results: We contacted 96% of the 4458 persons with such lesions among the 282,555 screenings in the 1992-1994 programs. We obtained a final diagnosis for 72%, and the positive predictive value for melanoma was 17%. Three hundred seventy-one melanomas were found in 364 persons. More than 98% had localized disease. More than 90% of the confirmed melanomas with known histology were in situ or "thin" lesions (< or = 1.50 mm thick). The median thickness of all melanomas was 0.30 mm. The 8.3% of AAD cases with advanced melanoma (metastatic disease, regional disease, or lesions > or = 1.51 mm) is a lower proportion than that reported by the 1990 Surveillance, Epidemiology and End Result Registry. The rate of thickest lesions (> or = 4 mm) and late-stage melanomas among all participants was 2.83 per 100,000 population. Of persons with a confirmed melanoma, 39% indicated (before their examination) that without the free program, they would not have considered having a physician examine their skin., Conclusion: The 1992-1994 free AAD programs disseminated broad skin cancer educational messages, enabled thousands to obtain a free expert skin cancer examination, and found mostly thin, localized stage 1 melanomas (usually associated with a high projected 5-year survival rate). Because biases impose possible limitations, future studies with long-term follow-up and formal control groups should determine the impact of early detection programs on melanoma mortality.

Objectives: To identify groups for melanoma prevention and early detection programs, this study explored the hypothesis that survival with cutaneous melanoma is disproportionately lower for persons of lower socioeconomic status., Methods: Massachusetts Cancer Registry and Registry of Vital Records and Statistics data (1982 through 1987) on 3288 incident cases and 1023 deaths from cutaneous melanoma were analyzed. Mortality/incidence ratios were calculated and compared, predictors of late stage disease were examined with logistic regression analysis, and a proportional hazards regression analysis that used death registration as the outcome measure for incident cases was performed., Results: Lower socioeconomic status was associated with a higher mortality/incidence ratio after adjustment for age and sex. For education, the mortality/incidence ratio was 0.37 in the lower group vs 0.25 in the higher group (rate ratio = 1.48, 95% confidence interval [CI] = 1.08, 2.03). Late stage disease was independently associated with lower income (rate ratio for lowest vs highest tertile = 1.64, 95% CI = 1.20, 2.25), and melanoma mortality among case patients was associated with lower education (rate ratio = 1.52, 95% CI = 1.09, 213)., Conclusions: Melanoma patients of lower socioeconomic status may be more likely to die from their melanoma than patients of higher socioeconomic status. Low- SES communities may be appropriate intervention targets.

Objective: To evaluate the impact of adult tobacco use on the health of children., Design: A literature review identified relevant research reports. Meta-analysis was used to compute a pooled risk ratio for each condition studied. The risk ratios were combined with data on exposure rates to produce estimates of the population-attributable risk., Results: Each year, among American children, tobacco is associated with an estimated 284 to 360 deaths from lower respiratory tract illnesses and fires initiated by smoking materials, more than 300 fire-related injuries, 354,000 to 2.2 million episodes of otitis media, 5200 to 165,000 tympanostomies, 14,000 to 21,000 tonsillectomies and/or adenoidectomies, 529,000 physician visits for asthma, 1.3 to 2 million visits for coughs, and in children younger than 5 years of age, 260,000 to 436,000 episodes of bronchitis and 115,000 to 190,000 episodes of pneumonia., Conclusions: The use of tobacco products by adults has an enormous adverse impact on the health of children. Although more research is needed in several areas, action to reduce the morbidity and mortality among children should not be delayed. New laws and policies are needed to grant children protection from bodily injury and death attributable to use of tobacco products by others.

The yeast Saccharomyces cerevisiae ste6 mutant is defective in transport of a-mating factor, resulting in an inability of ste6 a cells to mate with alpha cells. The gene encodes an ATP-binding cassette, ABC transporter. We used functional complementation of a yeast ste6 mutant with an Arabidopsis thaliana expression library in an attempt to clone an Arabidopsis homolog. Sequence analysis of the isolated Arabidopsis complementing cDNA however showed no homology to the STE6 gene. High sequence similarity was detected to members of the mitogen-activated serine/threonine protein (MAP) kinase family involved in signal transduction: STE20, STE11, BCK1, Byr2 and p65PAK. The Arabidopsis clone failed to complement a fus3/kss1 mutant of S. cerevisiae, but did complement a defect in ste11, ste20, as well as ste6. The isolated clone encodes a protein that is truncated at its amino-terminal, and might function in a similar way as a dominant STE11 truncation allele. These results suggest that the Arabidopsis cDNA encodes a putative serine/threonine kinase that can function in the mating response pathway upstream of FUS3/KSS1 in S. cerevisiae, at the level of STE11 gene. Interestingly, this clone is able to restore the ability of the ste6 yeast mutant to export a-factor.

In our study, age-matched Holtzman Sprague-Dawley rats (275-300 g) received injections with either saline (0.9%) or 3,4-methylenedioxymethamphetamine (MDMA; 20 mg/kg free base, s.c) twice daily for 4 days and allowed to recover for 2, 8, 16, 32 and 52 wk after the final injection before death. Radioligand binding studies with 125I-RTI-55 to dopamine uptake sites in striatal homogenates showed no effect of MDMA on the density of dopamine uptake sites. In contrast, saturation binding studies with 125I-RTI-55 to 5-HT uptake sites in hippocampal and frontal-parietal homogenates showed a significant reduction in the number of uptake sites at 2 wk after MDMA treatment (34 and 25%, respectively of controls). By 16 wk, a partial recovery in the number of 5-HT uptake sites was observed in both tissues; however, only a full recovery of serotonin uptake sites was observed in hippocampus at the end of 52 wk. In more detailed studies using autoradiography with 125I-RTI-55, recovery of serotonin uptake sites varied from region to region. In particular, recovery of 5-HT uptake sites in cerebral cortex was observed to follow a rostral-caudal gradient. In addition, recovery of 5-HT uptake site in hippocampus also followed a rostral-caudal gradient. Different rates of recovery of 5-HT uptake sites were also observed for cingulate cortex, laterodorsal thalamus and ventromedial hypothalamus. No effect of MDMA was observed over lateral hypothalamus, substantia nigra and ventral tegmental area, or over serotonergic cell bodies such as dorsal raphe and median raphe. In conclusion, our study is consistent with previous studies describing the selective neurotoxicity of MDMA for serotonin neurons and presents evidence showing the rate of recovery of 5-HT uptake sites varies according to region and that recovery of 5-HT uptake sites in neocortex and hippocampus follows a rostral-caudal gradient.

Patients infected with human immunodeficiency virus (HIV) are at risk for a variety of liver diseases. We undertook a retrospective study of 501 HIV-seropositive patients to assess the yield of percutaneous liver biopsy. The most common indications for liver biopsy were liver test abnormalities (89.5%), fever for 2 weeks (71.9%), and hepatomegaly (52.0%). The most common biopsy-derived diagnosis was Mycobacterium avium complex (MAC), seen in 87 (17.4%) biopsies. Mycobacterium tuberculosis was found in 13 biopsies (2.6%). In 28 biopsies (5.6%) mycobacteria was seen, but speciation of the organism was not possible. Chronic active viral hepatitis was seen in 60 biopsies (12.0%). Opportunistic hepatic infection from other organisms was found in 14 biopsies (2.8%). The most common neoplasm was lymphoma, which was seen in 12 biopsies (2.4%). MAC infection of the liver was associated with elevated alkaline phosphatase (p = 0.01). Among patients with fever for 2 weeks after an extensive negative workup including bone marrow biopsy, 58.2% had a diagnosis by liver biopsy. Overall, 64.3% of liver biopsies yielded a histopathological diagnosis, 45.7% of which were potentially treatable. We could not evaluate whether liver biopsy had a positive effect on patient outcome and survival, nor did we attempt to prove that liver biopsy resulted in a change in treatment or a change in preprocedure clinical diagnosis. Thus, questions about the efficacy of liver biopsy cannot be answered. Liver biopsy may be a helpful diagnostic tool in HIV-positive patients with fever, liver test abnormalities or hepatomegaly.

The effects of a high dose methylenedioxymethamphetamine (MDMA) regimen on the serotonin (5-HT) system were evaluated over a 52-wk period. MDMA was administered to rats (20 mg/kg) 8 times at 12-hr intervals. Tissue concentrations of dopamine (DA) and 5-HT, and synaptosomal uptake of 3H-5-HT and 3H-DA were measured at 2, 8, 16, 32 or 52 wk posttreatment. Synaptosomal uptake of 3H-5-HT (hippocampus) was decreased at 2 and 8 wk, but not at 16, 32 or 52 wk after drug. 5-HT tissue concentrations were measured in frontal cortex, frontal-parietal cortex, occipital-temporal cortex, nucleus accumbens/olfactory tubercle, striatum, amygdala, hippocampus, septum, hypothalamus, ventral tegmentum/substantia nigra. Two weeks after MDMA treatment, all regions showed decreased 5-HT tissue concentrations except septum. Recovery over the 52-wk interval was noted for all depleted regions, but the rate and degree of recovery was region dependent. Frontal-parietal cortex, occipital-temporal cortex and hippocampus showed the least recovery, with significant depletions at 52 wk posttreatment. Hypothalamus showed an increase in 5-HT tissue concentrations relative to age-matched controls at 52 wk. These results indicate that a high-dose MDMA regimen results in long-lasting depletions of serotonin. The rate and degree of recovery of serotonin tissue concentrations seen over the 52-wk test period is region specific.

Study Design: This article reviews the criteria for evaluating the quality of clinical trials., Objectives: To outline the current methodologic standards by which the validity of controlled trials need to be evaluated., Summary of Background Data: Weber's study, published in 1983 in Spine, is the only randomized trial comparing surgery and conservative management of sciatica in herniated lumbar discs., Methods: Weber's article is revisited to illustrate basic principles in the design of clinical trials., Results: Weber's study is a classic in spine surgery and has changed thinking regarding the benefit of surgery in sciatica related to herniated lumbar discs. However, the authors found potentially critical flaws in this study: a large number of crossovers, inadequate sample size, and insensitive outcome measurements., Conclusions: A randomized, controlled trial is the most rigorous way to evaluate health intervention. Despite the difficulties of performing such studies, investigators should use the most appropriate scientific methodology.

Growing hyphae of the ascomycete fungus Neurospora crassa contained a tip-high gradient of cytoplasmic Ca2+, which was absent in non-growing hyphae and was insensitive to Gd3+ in the medium. Patch clamp recordings in the cell-attached mode, from the plasma membrane of these hyphae, showed two types of channel activities; spontaneous and stretch activated. The spontaneous channels were identified as inward K+ channels based on inhibition by tetraethylammonium. The stretch activated channels had increased amplitudes in response to elevated Ca2+ in the pipette solution, and thus are permeable to Ca2+ and mediate inward Ca2+ movement. Gd3+, which is an inhibitor of some stretch activated channels, incompletely inhibited stretch activated channel activity. Both tetraethylammonium and Gd3+ only transiently reduced the rates of tip growth without changing tip morphology, thus indicating that the channels are not absolutely essential for tip growth. Furthermore, in contrast to the hyphae of another tip growing organism, Saprolegnia ferax, tip-high gradients of neither spontaneous nor stretch activated channels were found. Voltage clamping of the apical plasma membrane potential in the range from -300 to +150 mV did not affect the rates of hyphal elongation. Collectively, these data suggest that ion transport across the plasma membrane at the growing tip in Neurospora is not obligatory for the maintenance of tip growth, but that a gradient of Ca2+, possibly generated from internal stores in an unknown way, is required.

The purpose of this study was to validate the results of a meta-analysis showing the efficacy of fish oil in rheumatoid arthritis with the results of a re-analysis of the complete primary data set. A Medline search yielded seven published papers. Three additional trials were found by contacting authorities in the field. Inclusion criteria included (1) a double-blind, placebo-controlled study, (2) use of at least one of seven predetermined outcome measures, (3) results reported for both placebo and treatment groups at baseline and follow-up, (4) randomization, and (5) parallel or cross-over design. Papers were scored for quality. Demographic and outcomes variables were collected. For the re-analysis of the primary data, the same variables were abstracted for the 395 individual patients randomized. The meta-analysis demonstrated that dietary fish oil supplementation for 3 months significantly reduced tender joint count (rate difference [RD] [95% CI] = -2.9 [-3.8 to -2.1] [p = 0.001]) and morning stiffness (RD [95% CI] = -25.9 [-44.3 to -7.5] [p < 0.01]) as compared with heterogeneous dietary control oils. The re-analysis of the primary data confirmed a significant reduction in tender joint count (p = 0.001) and in morning stiffness (p < 0.02) in the parallel analysis that ignored interaction terms. The analyses that included an interaction term between site and treatment again confirmed a significant reduction in tender joint count. The results for morning stiffness were similar to the meta-analysis, but did not quite reach statistical significance (p = 0.052-0.083). The relative improvements in the other outcome variables did not reach statistical significance. Use of fish oil improved the number of tender joints and duration of morning stiffness at 3 months as analyzed by both meta- and mega-analysis. The fuller mega-analysis confirmed the results of the meta-analysis. The advantages of mega-analysis were as follows: (1) the ability to analyze the homogeneity of the patient populations, (2) the ability to make clinically sensible adjustments in the form of the comparison, and (3) the ability to examine subsets of the data.

To develop a technique to screen populations for potential connective tissue disease (CTD), we mailed a 30-item questionnaire to 253 randomly selected patients with systemic lupus erythematosus, rheumatoid arthritis, scleroderma, polymyositis, dermatomyositis, mixed connective tissue disease (MCTD), or Sjögren's syndrome and to 340 randomly selected control subjects. The response rate after four mailings was 71% for case subjects and 54% for control subjects. Test-retest reliability for detection of any CTD was 0.82. Sensitivity for specific CTDs was 83 to 96% and specificity was 83 to 93%. The positive predictive value for any CTD (assuming an overall prevalence of 1.3%) was 5.5%; negative predictive value was 99.7%. The CTD Screening Questionnaire has high sensitivity and specificity for screening large populations.

Multiple strategies are required to combat the increasing incidence and mortality of cutaneous melanoma. Major questions about melanoma and skin cancer are reviewed, with particular attention to education and early detection.

Study Design: Prospective multicenter observational study of the outcome of surgery for degenerative lumbar spinal stenosis., Objectives: To identify correlates of patient satisfaction with the results of surgery., Summary of Background Data: Little published information exists on correlates of patient satisfaction after surgery for spinal stenosis., Methods: Preoperative and 6-month follow-up data for 194 patients were analyzed. Associations between preoperative variables and satisfaction with the results of surgery were examined in univariate and multivariate models., Results: In multiple linear regression models that adjusted for the effects of age, gender, individual surgeon, number of interspaces decompressed, whether a fusion was performed, depression score, and overall level of pain, the predominance of back (as opposed to leg) pain, greater comorbidity, and worse preoperative functional status were associated with lower patient satisfaction. The regression model explained just 15% of the variance in patient satisfaction., Conclusions: Patients bothered predominantly by back pain preoperatively and those with greater medical comorbidity and functional disability are significantly less satisfied with the results of surgery for degenerative lumbar spinal stenosis.

We have characterized and compared the substrate specificity of affinity-purified recombinant rat testes endopeptidase EC 3.4.24.15 (EP 24.15) with that reported for the isolated brain enzyme. Of the peptides tested, only bradykinin, dynorphin A1-8, and neurotensin were efficiently cleaved by the recombinant enzyme (kcat/Km = 3.0, 2.8 and 0.5 x 10(5) M-1sec-1, respectively); other peptides considered substrates of EP 24.15 (gonadotropin-releasing hormone, substance P, somatostatin and angiotensin) were not metabolized. The enzyme was inhibited by metal ion chelators and thiol-reactive agents, as well as a specific EP 24.15 inhibitor (N-[1(R,S)-carboxy-3-phenylpropyl]-Ala-Ala-Tyr-p-aminobenzoate), thus confirming the enzyme as a thiol-dependent metalloendopeptidase. The observed discrepancies in substrate specificity of the recombinant testicular and the isolated brain enzymes may result from tissue-specific forms and/or post-translational modifications of EP 24.15.

Background: The purpose of this study was to estimate the annual morbidity and mortality among fetuses and infants that can be attributed to the use of tobacco products by pregnant women., Methods: Published research reports identified by literature review were combined in a series of meta-analyses to compute pooled risk ratios, which, in turn, were used to determine the population attributable risk., Results: Each year, use of tobacco products is responsible for an estimated 19,000 to 141,000 tobacco-induced abortions, 32,000 to 61,000 infants born with low birthweight, and 14,000 to 26,000 infants who require admission to neonatal intensive care units. Tobacco use is also annually responsible for an estimated 1900 to 4800 infant deaths resulting from perinatal disorders, and 1200 to 2200 deaths from sudden infant death syndrome (SIDS)., Conclusions: Tobacco use is an important preventable cause of abortions, low birthweight, and deaths from perinatal disorders and SIDS. All pregnant women should be advised that smoking places their unborn children in danger. The low success rate of smoking cessation among pregnant women suggests that efforts to reduce the complications of pregnancy attributable to tobacco use by pregnant women should focus on preventing nicotine addiction among teenaged girls.

1. We investigated the role of angiotensin converting enzyme (ACE) in the cardiovascular effects of N-[1-(R,S)-carboxy-3-phenylpropyl]-Ala-Ala-Tyr-p-aminobenzoate (cFP), a peptidase inhibitor selective for metalloendopeptidase (EP) E.C. 3.4.24.15. 2. In conscious rabbits, cFP (5 mg kg-1, i.v.) markedly slowed the degradation of [3H]-bradykinin, potentiated the depressor response to right atrial administration of bradykinin (10-1000 ng kg-1), and inhibited the pressor response to right atrial angiotensin I (10-100 ng kg-1). In each of these respects, the effects of cFP were indistinguishable from those of the ACE inhibitor, captopril (0.5 mg plus 10 mg kg-1h-1 i.v.). Furthermore, the effects of combined administration of cFP and captopril were indistinguishable from those of captopril alone. 3. In experimentally naive anaesthetized rats, cFP administration (9.3 mg kg-1, i.v.) was followed by a moderate but sustained fall in arterial pressure of 13 mmHg. However, in rats pretreated with bradykinin (50 micrograms kg-1) a more pronounced fall of 30 mmHg was observed. Captopril (5 mg kg-1) had similar hypotensive effects to those of cFP, and cFP had no effect when it was administered after captopril. 4. CFP displaced the binding of [125I]-351A (the p-hydroxybenzamidine derivative of lisinopril) from preparations of rat plasma ACE and solubilized lung membrane ACE (KD = 1.2 and 0.14 microM respectively), and inhibited rat plasma ACE activity (KI = 2.4 microM). Addition of phosphoramidon (10 microM), an inhibitor of a range of metalloendopeptidases, including neutral endopeptidase (E.C.3.4.24.11), markedly reduced the potency of cFP in these systems. 5. Taken together these findings suggest that the actions of cFP in vivo are attributable to inhibition of ACE rather than EP 24.15. Given that cFP is a poor inhibitor of ACE in the presence of phosphoramidon in vitro, it is likely that cFP is cleaved by a phosphoramidon-sensitive metallopeptidase in vivo to liberate N-[1-(R,S)-carboxy-3-phenylpropyl]-Ala-Ala, a potent ACE inhibitor.

Objective: We studied the relationship between systemic lupus erythematosus (SLE) morbidity and socioeconomic status (SES) at 5 centers., Methods: Ninety-nine patients who met American College of Rheumatology criteria for SLE were randomly sampled at each center, balancing by race and insurance status. Subjects were interviewed for current and past SES factors, such as insurance, occupation, employment, education, and income. SLE disease activity was measured by the SLE Activity Measure (SLAM)., Result: Higher education, private insurance/Medicare, and higher income were associated with less disease activity at diagnosis. Controlling for SES, race, and center, the best predictors of less active disease at diagnosis were private insurance/Medicare (P = 0.002) and higher education (P = 0.007). From the time of diagnosis to the study visit (mean 3.5 years), insurance, income, and employment status changed for a significant number of subjects (37%, 16%, and 21%, respectively)., Conclusion: Private insurance or Medicare and higher education are associated with less active disease at diagnosis of SLE. Health insurance, income, and employment status are unstable measures of socioeconomic status and may explain the variability in conclusions of previous studies on the role of SES in SLE.

Cutaneous melanoma is an increasingly common public health problem in industrialized nations. In theory, education and early detection should decrease melanoma morbidity and mortality, because the lesion is external and visible, risk factors are known, and thin tumors are associated with a high 5-year survival rate. The efficacy of early detection and screening programs, however, remains untested by randomized trials. Some early data are available from melanoma prevention and control efforts that have begun in many nations over the past decade. Textbook definitions of cancer screening are particularly challenging when applied to skin cancer control. Although some propose that there are rigid differences among screening, education, and early detection of skin cancer, the visible nature of this cancer makes early detection through education and screening inextricably intertwined. This article discusses the intermediate measures of education and screening within the context of the American Academy of Dermatology programs. Over the next few decades, screening and education for melanoma and other skin cancer will receive increasing worldwide attention. Multiple strategies will be required to combat increasing incidence and mortality rates. Screening and educational programs have been implemented worldwide, but data on their effects are only just being collected. Future collaborative work in melanoma/skin cancer prevention, education, and early detection holds promise as a way to decrease mortality and save lives.

Responsiveness, the ability to detect meaningful clinical change, is a critical attribute of instruments used to evaluate outcomes of treatments. The authors hypothesized that self-administered symptom severity and functional status questionnaires are more responsive to clinical improvement after carpal tunnel release than traditional physical examination measures of strength and sensibility. Data were obtained from a randomized clinical trial of endoscopic versus open carpal tunnel release conducted in four university medical centers. Patients were evaluated before surgery and 3 months after surgery. Seventy-four patients indicating that they were more than 80% satisfied with the results of surgery were assumed to have clinically meaningful improvement and were the focus of the analysis. Evaluations included questionnaires assessing symptom severity, functional status, and activities of daily living as well as measurement of grip, pinch, and abductor pollicus brevis strength, and 2-point discrimination and Semmes-Weinstein pressure sensibility. Responsiveness was calculated with the standardized response mean (mean change/standard deviation of change) as well as the effect size (mean change/standard deviation of baseline values). The symptom severity scale was four times as responsive, and the functional status and activities of daily living scales were twice as responsive, as the measures of strength and sensibility. Self-administered symptom severity and functional status scales are much more responsive to clinical improvement than measures of neuromuscular impairment and should severe as primary outcomes in clinical studies of therapy for carpal tunnel syndrome.

Background: Leg ulcers affect probably 2.5 million persons in the United States, and their prevalence is likely to rise as the population ages. They cause considerable disability, and the cost of treating these chronic wounds is enormous., Objective: The purpose of this study was to assess the financial, social, and psychologic implications of leg ulcers., Methods: Data were collected by standardized personal interviews with 73 patients with chronic leg ulcers. The interview covered several domains that were selected to determine the impact of a leg ulcer on overall quality of life., Results: A significant number of patients had moderate to severe symptoms, principally pain, related to the leg ulcer. Eighty-one percent believed that their mobility was adversely affected by the ulcer; the dominant predictor of impaired mobility was swelling of the leg (p < 0.001). For younger, working patients, leg ulceration was correlated with time lost from work (p < 0.001), job loss (p < 0.01), and adverse effects on finances (p < 0.02). Fifty-eight percent of patients found caring for the ulcer burdensome. There was a strong correlation between time spent on ulcer care and feelings of anger and resentment. Sixty-eight percent of patients reported that the ulcer had a negative emotional impact on their lives, including feelings of fear, social isolation, anger, depression, and negative self-image., Conclusion: Leg ulcers pose a substantial threat to a variety of dimensions of a patient's quality of life.

Multiple outcomes are assessed in most studies of carpal tunnel syndrome, yet there are no validated methods of synthesizing these distinct measures into a single global score. We report a global score in which outcomes were selected and weighted according to their independent association with patient satisfaction with the results of surgery. Preoperative and 3-month follow-up data were analyzed on 104 subjects in a randomized controlled trial of open vs endoscopic carpal tunnel release. Patient satisfaction with surgery and a variety of subjective and objective outcome parameters were measured. In multivariate analyses, independent correlates of dissatisfaction included persistent numbness and paresthesia, incisional pain at follow-up evaluation, and decrease in grip strength. A global score was calculated by rounding to the nearest integer the model coefficients for these three variables. The global score correlated with patient satisfaction with surgery and time until return to work or full activities in patients undergoing open carpal tunnel release.

We have previously shown that calcitonin (CT), an inhibitor of bone resorption, increases vertebral, but not femoral bone density in the rat. To address the physiologic responses associated with these effects on bone mineral density (BMD), we assessed mRNA transcripts reflecting activities of osteoblasts (type I collagen, osteocalcin, osteopontin, and alkaline phosphatase), osteoclasts [tartrate-resistant acid phosphatase (TRAP)], and cell proliferation (histone H4) in the spine and femur of these rats. CT increased spine BMD while increasing type I collagen and decreasing TRAP and histone mRNAs. In the femur, where CT had no effect on BMD, it decreased type I collagen and histone H4 mRNA but did not affect TRAP. CT had no effect on the gene expression of osteocalcin, osteopontin, or alkaline phosphatase at either site. The results indicate that selective alterations in gene expression, as reflected by steady state mRNA levels, are consistent with the changes observed by BMD measurement, and can more clearly define the specific contribution from osteoblast and osteoclast activity. This study demonstrates a heterogeneity in response of the axial and appendicular skeleton to CT, reflected by alterations in gene expression that provide a basis for understanding the observed BMD responses to various pharmacologic interventions.

The metalloendopeptidase EC 3.4.24.15 is believed to degrade gonadotropin-releasing hormone (GnRH) (pGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2) by cleavage at the Tyr5-Gly6 bond. We compared the ability of crude and partially purified endopeptidase 24.15 from ovine hypothalamus with recombinant rat testicular endopeptidase 24.15 to degrade synthetic GnRH. Both soluble and membrane hypothalamic fractions degraded GnRH to GnRH1-5, with some production of GnRH1-9 and GnRH1-3. Generation of the smaller fragments was blocked by a specific endopeptidase 24.15 inhibitor (CFP-AAY-pAB), but production of GnRH1-9 was reciprocally enhanced, suggesting this peptide may be an intermediate generated by prolyl endopeptidase. Indeed, both bacitracin and Z-Pro-prolinal, inhibitors of this enzyme, markedly reduced GnRH degradation to any product. Degradation of synthetic GnRH1-9 was more rapid than that of GnRH and was inhibited by CFP-AAY-pAB but not bacitracin. Activity against either substrate was greater in the soluble fraction. Repeated washing of the membrane fraction followed by extraction with Triton X-114 suggested that both endopeptidase 24.15 and prolyl endopeptidase, although predominantly soluble, can be peripherally associated with membranes. When fractionated by hydrophobic interaction chromatography, soluble endopeptidase 24.15 degraded GnRH only in fractions that also exhibited prolyl endopeptidase activity. In contrast, maximal degradation of GnRH1-9 was observed in adjacent fractions, which also contained the highest levels of immunoreactive endopeptidase 24.15. The affinity of recombinant endopeptidase 24.15 for GnRH was low (Km = 1.35 mM), was improved 10-15-fold by removal of the COOH-terminal amide or glycinamide (Km = 90 and 119 microM, respectively), and could be inhibited by CFP-AAY-pAB but not bacitracin. Taken together, these results suggest that GnRH metabolism in the hypothalamus may occur via a two-step process involving first removal of Gly10-NH2 by prolyl endopeptidase, followed by cleavage by endopeptidase 24.15 at the Tyr5-Gly6 bond.

The capillary endothelial cells of the median eminence represent a potential site for the degradation/modification of both circulating and hypothalamic peptides passing through the hypophysial portal system toward the pituitary. This study examines endothelial cell peptidase expression in vitro by monitoring the metabolism of gonadotropin-releasing hormone (GnRH) by cultured endothelial cells from sheep median eminence. Cleavage of GnRH by median eminence endothelial cell membranes generated GnRH1-5 as the primary stable product, which was then degraded to GnRH1-3 and free amino acids. Degradation of GnRH was completely inhibited by TPCK, ZnCl2 and N-ethylmaleimide, and partially inhibited by EDTA and by a specific inhibitor of the metalloendopeptidase EC 3.4.24.15, CFP-AAY-pAB. Interestingly, an increase in GnRH1-9 production was seen with the latter inhibitors, suggesting a two-step mechanism of GnRH degradation involving a primary cleavage at the Pro9-Gly10-NH2 bond, inhibitable by TPCK, ZnCl2, and NEM, followed by cleavage by EC 3.4.24.15 to generate GnRH1-5. Phosphoramidon and angiotensin converting enzyme inhibitors (as well as other non-specific inhibitors) were without effect, indicating that endopeptidase EC 3.4.24.11 and angiotensin converting enzyme are not involved. Neither bovine aortic endothelial cell nor AtT-20 cell membranes exhibited this pattern of peptidase activity. Degradation of GnRH by intact median eminence endothelial cells in culture was also observed, suggesting an extracellular orientation for these enzymes; the potential role of such peptidases in the fine regulation of both pituitary function and local blood flow is currently under investigation.

The accumulated data indicate that bone mineral density (BMD) is decreased in humans with insulin-dependent diabetes mellitus. The purpose of this study was to prospectively determine sequential lumbar and femoral BMD utilizing dual energy X-ray absorptiometry in rats that spontaneously become diabetic to determine if weight and blood glucose control would prevent the diabetes-related bone mass changes. BMD of the lumbar spine and femur was measured prior to the onset of diabetes and at 3-week intervals after the diagnosis of diabetes for 12 weeks in 14 diabetes-prone BB/Wor rats (DP) and eight diabetes-resistant BB/Wor control rats (DR). At 12 weeks, the lumbar (0.238 +/- 0.013 vs 0.262 +/- 0.007 g/cm2, P < 0.001) and femoral (0.313 +/- 0.013 vs 0.343 +/- 0.013 g/cm2, P < 0.001) BMD were significantly lower in the DP rats despite significantly greater body weights (387 +/- 26 vs 329 +/- 46 g, P < 0.001) and plasma glucose levels of only 178 mg/dl. There was no difference in plasma values of calcium, phosphorus, osteocalcin, or tartrate-resistant acid phosphatase between groups or differences in osteoblast numbers in histologic sections. There was a significant (P < 0.001) decrease in plasma creatinine in the diabetic animals. The results indicate that in this animal model of type I diabetes, spine and femoral BMD do not increase comparable to control despite weight and blood glucose control. This would suggest that the diabetic condition itself affects bone mass in the absence of weight loss and poor blood glucose control.

Homologies based on structural motifs characterize conserved structures and mechanisms of maintaining function. An algorithm was developed to quantitate homology among segments of two proteins based upon structural characteristics of an amphipathic alpha-helix. This helical mimicry algorithm scored homology among sequences of two proteins in terms of: (i) presence of Leu, Ile, Val, Phe, or Met in a longitudinal, hydrophobic strip-of-helix at positions n, n + 4, n + 7, n + 11, etc. in the primary sequence, (ii) identity or chemical similarity of amino acids at intervening positions and (iii) exchanges of amino acids from positions n to n - 1, n + 3, n + 4, n + 1, n - 3, n - 4 around n (on the surface of a putative helix). While such exchanges of amino acids on the surfaces of homologous helices may conserve function, they did not maintain specific interactions of those residues with apposing groups.

In the present studies, we characterized the degradation of gonadotropin-releasing hormone (GnRH) by tissues of the ovine hypothalamo-pituitary axis. Membrane and soluble fractions of the medial basal hypothalamus, the pre-optic area, the median eminence and the anterior pituitary demonstrated greater GnRH-degrading activity than either hypophysial-portal or jugular plasma. The primary stable product of the membrane fractions was GnRH1-3, while the major product of the soluble fractions was GnRH1-5, both fragments were generated by plasma. Of all tissue fractions, the highest specific activity was observed in the soluble median eminence. Partial purification and characterization of soluble hypothalamic peptidase activity suggested that GnRH degradation by this tissue occurs via a two-step mechanism involving both post-proline cleaving enzyme and the metalloendopeptidase 3.4.24.15.

Growing hyphal tips of the oomycete Saprolegnia ferax possess a tip-high gradient of stretch-activated ion channels permeable to calcium. These mechanosensitive channels appear to play a direct role in the polarized tip growth process. Treatment of S. ferax hyphae with cytochalasin E leads to the disruption of plasmalemma-associated, peripheral cytoplasmic actin populations and altered morphology of apical protoplasts, and eliminates the tip-high gradient of stretch-activated channels. Cytochalasin E did not alter the normal aggregation of stretch-activated channels. The density of spontaneous K+ channels was decreased in all regions of the hyphae after treatment with cytochalasin E. These results suggest that the peripheral F-actin network in the growing tip of S. ferax hyphae establishes or maintains the tip-high gradient of SA channels, either by the delivery of channel-bearing vesicles to the apex or by the interactions between the channels and the peripheral actin network.

Hydrophobic amino acids of the group Leu, Ile, Val, Phe, and Met (LIVFM) are distributed in favored or suppressed patterns within protein sequences. The frequencies of all five-position combinations of [symbol: see text] = LIVFM and [symbol: see text] = non-LIVFM residues were analyzed in 48 proteins of known crystallographic structure. Some motifs were strongly preferred or suppressed; e.g., [symbol: see text] was favored (z = 3.5), while [symbol: see text] was suppressed (z = -3.4). In longer patterns, [symbol: see text] followed by [symbol: see text] and one [symbol: see text] was favored ([symbol: see text], z = 5.1), while conversion of the single hydrophobic residue to a pair was not ([symbol: see text], z = 0.8). Distributions of certain non-LIVFM amino acids around [symbol: see text] positions in strongly favored patterns were also favored or disfavored (Asp, Glu, Lys, Arg, Asn, Cys, Tyr, and Pro; for each magnitude of z > 2.0). While the strongly favored pattern [symbol: see text] was found in both alpha-helical and beta-strand sequences, it associated significantly with alpha-helices (z = 3.6 for the second-position alpha-helical phi and psi angles) but not with beta-strands (z = -1.1). Certain motifs of LIVFM and non-LIVFM residues might be selected if they lead efficiently to the local nucleations hypothesized to characterize molten globule intermediates in the folding of proteins.

Upon addition of requirements for highly characteristic distributions of helix-stabilizing residues to an alpha-helix predictor based upon identification of a longitudinal, hydrophobic strip-of-helix pattern, maximal sensitivity and efficiency scores approached 50% levels at a high degree of stringency. The hydrophobic strip-of-helix template ([symbol: see text], joined in a circle) was applied to 247 helices to maximize the strip-of-helix hydrophobicity index (SOHHI; the mean hydrophobicity of residues in [symbol: see text] positions). Statistically significant increases or decreases in the frequencies of certain residues are observed in some [symbol: see text] and [symbol: see text] positions: [symbol: see text] in the helix (including N- and C-terminal [symbol: see text] in the helix): Leu, Ile, Val, Phe, and Met; first [symbol: see text] positions in extensions of the template to surrounding segments: not increased Leu, Ile, Val, Phe, or Met; N-terminal [symbol: see text]: Asp, Glu; C-terminal [symbol: see text] and the first [symbol: see text] after the helix: His, Lys, Arg; N-terminal [symbol: see text]: Asn; C-terminal [symbol: see text]: Gln; smallest residue in longitudinal strip-of-helix: Ala or Val at crossing points between helices. An algorithm was then derived to indicate alpha-helices by merging predictions with templates [symbol: see text] and [symbol: see text], where the SOHHI > or = 3.0 in the Kyte-Doolittle scale. Relative to the baseline prediction using only the template, more elaborate rules using combinations of other structural patterns produced more efficient (49 versus 42%, respectively) but less sensitive (32 versus 42%, respectively) predictions when the prediction was required to overlap substantially with the known helix. These maximal sensitivities and efficiencies imply that some helices may be formed in folding intermediates but are lost upon coalescence of the final form. Better predictions of protein structure from the primary sequence may require modeling of competing interactions of local structures in folding intermediates.

Dendritic cells (DC) present antigen and initiate T cell-mediated immune responses. To investigate the possible association of autoimmunity with DC function, we compared the accessory activity of splenic DC from Wistar/Furth (WF) and diabetes-prone (DP) BioBreeding (BB) rats. The latter develop autoimmune diabetes and thyroiditis. DC function was quantified in vitro by measuring T cell proliferation in mitogen-stimulated and mixed lymphocyte reactions. When purified without macrophage coculture, WF and DP DC displayed similar levels of accessory activity. In contrast, when purified by a method involving coculture with macrophages, DC from DP rats consistently displayed greater accessory activity. This finding could not be explained by morphological or phenotypic differences between DP and WF DC. In accessory activity assays performed after reciprocal DC cocultures with DP and WF macrophages, DP DC exhibited higher accessory activity irrespective of macrophage donor strain. We also compared the accessory activity of WF and DP DC cultured in the presence of conditioned medium and a mixture of IL-1 and GM-CSF. In all assays, DP DC exhibited higher accessory activity. In studies of (WF x DP) F1 hybrids, the high accessory activity of DP DC was observed to be heritable, and studies of WF and DP radiation chimeras indicated that the effect was an intrinsic property of the DP hematopoietic system. We conclude: (a) splenic DC from DP and WF rats possess similar basal levels of accessory potency; (b) after interaction with macrophages, DC of DP origin are capable of greater stimulatory activity than are WF DC; and (c) the mechanism responsible for this phenomenon involves differential responsiveness of DP and WF DC to macrophage-derived factors such as IL-1 and GM-CSF.

Apart from the well recognized factors that are produced by the hypothalamus and secreted into hypophysial portal blood to regulate pituitary function, there is a range of neuropeptides that are present in the median eminence and could be secreted to serve a modulatory function. In this study we have collected hypophysial portal blood and jugular venous blood from sheep in an attempt to identify which of these putative modulatory peptides might be secreted from the median eminence. We have measured neuropeptide Y (NPY), substance P (SP), galanin (GAL), neurokinin A (NKA), peptide histidine isoleucine (PHI), vasoactive intestinal peptide (VIP), neurotensin (NT) and cholecystokinin (CCK). We also examined the sheep median eminence using immunohistochemistry for NPY, SP and GAL and determined degradation profiles of NPY, SP, GAL and NKA in portal and jugular plasma. In no instance did we find that levels of the above peptides were consistently higher in portal blood than in peripheral blood. In some cases levels of peptide were lower in portal plasma e.g. for NPY (6/10 sheep). In one experimental series SP levels in portal plasma were significantly (p < 0.05) lower than levels in jugular plasma but this was not found in another experimental series. Galanin levels were significantly (p < 0.01) lower in portal plasma compared to levels in jugular plasma. We conducted in vitro studies to determine whether or not the above peptides are selectively degraded in portal blood but were unable to show any differences between the rates of degradation in portal and jugular plasma. Immunohistochemistry revealed projections into the external zone of the median eminence for NPY, GAL and SP. This study shows that none of the above peptides are secreted into the hypophysial portal blood of sheep. For some peptides e.g. GAL, enzymes from the endothelial cells of the portal vessels may enhance degradation. Projections into the external zone of the median eminence of neuronal systems containing these peptides may serve to modulate the secretion of the well recognized release and inhibiting factors by acting on the neurosecretory terminals.

The plasma membrane of tip-growing hyphae of the oomycete Saprolegnia ferax contains stretch-activated (SA) Ca(2+)-permeable and Ca(2+)-activated K+ ion channels. Patch clamp measurements on protoplasts derived from specific regions of hyphae demonstrated that SA channels were most abundant in the tip. Gadolinium (Gd3+) inhibited SA channel activity and stopped tip growth. The Ca(2+)-sensitive fluorochrome INDO 1 revealed a tip-high gradient of free cytoplasmic Ca2+ in growing hyphae. This gradient could be dissipated with the addition of Gd3+. The calcium gradient returned and growth resumed when Gd3+ was washed out. This implies a fundamental requirement for growth for Ca2+ influx through the SA channels. Ca(2+)-activated K+ channels were distributed evenly along the hyphae. These channels were inhibited by tetraethylammonium concentrations which caused a rapid but transient decrease in growth. We suggest that the SA channels at the apex act as feedback sensors, responding to membrane stretching at the tip. They are an obligate requirement for tip growth. The Ca(2+)-activated K+ channels may act to maintain turgor pressure, but are not obligatory for growth.

1. Levels of peptidylglycine alpha-amidating mono-oxygenase (PAM) activity were examined in sheep and rat heart. This enzyme is responsible for alpha-amidation of a large number of peptide hormones, a modification essential for the bioactivity of these peptides. 2. PAM activity was measured in membrane and soluble fractions of atrial and ventricular homogenates by monitoring the amidation of iodinated synthetic substrate ([125I]-Ac-Tyr-Val-Gly). 3. PAM activity in both species resided almost exclusively in the atria rather than the ventricles, and similar levels of activity were found in left and right atria. Membrane-associated activity was 50-to 100-fold greater than soluble activity in the sheep, yet was only five- to 10-fold greater in the rat, indicating a larger proportion of soluble enzyme in the rat atrium. 4. Similar apparent Km values were found for atrial membrane-associated activity in both species (15.6 and 17.4 mumol/L for rat right and left atria, 16.7 and 15.6 mumol/L for sheep right and left atria); however, the maximum velocity (Vmax) levels were higher in the rat (40.5 and 43.9 pmol/micrograms per h vs 12.8 and 15.1 pmol/micrograms per h). 5. Because expression of many peptides and processing enzymes can be regulated by steroid hormones, the possible effects of chronic glucocorticoid administration (1 mg dexamethasone i.m. twice daily for 10 days) on PAM levels were tested in four sheep, with four sheep receiving saline only as controls. There was no discernible effect of dexamethasone on either the distribution or the kinetics of PAM activity in the sheep heart.(ABSTRACT TRUNCATED AT 250 WORDS)

Although the precise etiology of melanoma remains unknown, much data link sunlight to melanoma. The imperfect evidence associating sun exposure (particularly UVB radiation) with melanoma emerges from human data, obviating problems inherent in extrapolation from animal and other models. However, the mechanism by which sunlight might possibly initiate or promote melanoma remains obscure. Some clarification should emerge from the potential isolation of genes that carry susceptibility to melanoma in families prone to the disease; such work could serve as a basis to distinguish genetic and environmental influences in melanoma [167]. Continued studies of faulty DNA repair in XP patients may elucidate the steps in mutagenesis and carcinogenesis. Future case-control studies must address the limits on the accuracy of recall and the limits on statistical methods to separate the cluster of phenotypic risk needed in determining biologically effective dose. Animal and in vitro studies must contribute more insight. Further research in the South American opossum models appears promising [72]. Although ozone depletion has been documented, there has been little definitive evidence of subsequent increase of UVB at the Earth's surface. Nevertheless, the threat posed by ozone depletion deserves continued environmental action and public education. The role of precursor lesions, particularly dysplastic nevi/atypical moles, must be clarified with future research. The distribution of melanoma among various work forces suggests that occupational risk factors may play an important role in the etiology of this disease [168-170]. The consistent reports of excess melanoma among accountants, clerical workers, professional workers, and teachers deserve further study. Furthermore, evidence of excesses in printing and press, petrochemical, and the telecommunications industries require follow-up. Carefully planned studies that account for nonoccupational risk factors are recommended. Research over the last four decades has brought much information about melanoma etiology. More work is needed to learn the precise cause and ultimately to prevent avoidable mortality from malignant melanoma.

In a peptide with a T cell-presented epitope (T site), a folded structure with a hydrophobic surface, 'the scavenger (S) site', may regulate transfer to major histocompatibility complex class II molecules. Three procedures which were proposed to identify T sites selected for amphipathic helical patterns but not T sites. In testing whether S sites lay in or near T sites, we found their linkage was not greater than that generated by a model in which segments of equal length and number to the S and T sites for each protein were distributed at random. This study establishes criteria for evaluation of schemes to predict functional motifs in antigenic proteins.