Treatment options for type 2 diabetes in adolescents and youth: a study of the comparative efficacy of metformin alone or in combination with rosiglitazone or lifestyle intervention in adolescents with type 2 diabetes

Despite the increased prevalence of type 2 diabetes mellitus (T2DM) in the pediatric population, there is limited information about the relative effectiveness of treatment approaches. This article describes the rationale and design of a National Institutes of Health-sponsored multi-site, randomized, parallel group clinical trial designed to test the hypothesis that aggressive reduction in insulin resistance early in the course of T2DM is beneficial for prolongation of glycemic control, as well as improvement in associated abnormalities and risk factors. Specifically, the trial compares treatment with metformin with two alternate approaches, one pharmacologic (combining metformin treatment with rosiglitazone) and one combining metformin with an intensive lifestyle intervention program. The Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) study recruits 800 patients over a 4-yr period and follows them for a minimum of 2 yr and maximum of 6 yr. Patients are 10-17 yr of age, within 2 yr of diagnosis of diabetes at the time of randomization, lack evidence of autoimmunity, and have sustained C-peptide secretion. The primary outcome is time to loss of glycemic control, defined as a hemoglobin A1c >8% for 6 consecutive months. Secondary outcomes include the effect of the alternative treatments on insulin secretion and resistance, body composition, nutrition, physical activity and fitness, cardiovascular risk monitoring, microvascular complications, quality of life, depression, eating pathology, and resource utilization. TODAY is the first large-scale, systematic study of treatment effectiveness for T2DM in youth. When successfully completed, this study will provide critical new information regarding the natural history of T2DM in youth, the benefits of initiating early aggressive treatment in these patients, and the efficacy of delivering an intensive and sustained lifestyle intervention to children with T2DM.

Comparison of Sarcoidosis Phenotypes Among Affected African-American Siblings

STUDY OBJECTIVE

To test the hypothesis that sibling pairs, who share genes and environmental exposures, might have similar phenotypic expressions of sarcoidosis beyond what would be expected by chance alone.

DESIGN

Multicenter family study with study subjects recruited from 11 clinical centers.

SUBJECTS

Subjects were African-American sibling pairs with sarcoidosis. Sarcoidosis and organ pattern involvement were defined according to specific criteria. Fifteen different organ systems were evaluated.

RESULTS

For full-sibling pairs, ocular involvement was found in both siblings more often than expected by chance alone (p < 0.05), but the concordance was weak (kappa = 0.18). When analyzing full-sibling and half-sibling pairs, ocular and liver involvement showed a significant concordance between sibling pairs (p < 0.05), but again the agreement was poor (kappa = 0.16 for both). Concordance in pulmonary function change over time was also weak. Clinical outcomes of sibling pairs were not significantly correlated except for whether treatment was prescribed, and this level of agreement was poor (kappa = 0.14 for full-sibling and half-sibling pairs; kappa = 0.15 for full-sibling pairs only). Modeling phenotypic expression in sibling pairs using logistic regression did show that the presence of ocular and liver sarcoidosis in the first affected sibling conferred a statistically significant increased risk to the second affected sibling for having those organs involved (odds ratio [OR], 3; 95% confidence interval [CI], 1.7 to 5.4 for ocular; OR, 3.3; 95% CI, 1.5 to 7.4 for liver).

CONCLUSIONS

The phenotypic features and clinical outcomes of sarcoidosis in sibling pairs show minimal concordance, with the possible exception that the presence of ocular or liver involvement in the first sibling with a diagnosis of sarcoidosis makes involvement of these organs more likely in other affected siblings.

Presence of diabetes risk factors in a large U.S. eighth-grade cohort

OBJECTIVE

The study was conducted in 12 middle schools to determine the prevalence of diabetes, pre-diabetes, and diabetes risk factors in eighth-grade students who were predominantly minority and evaluate the feasibility of collecting physical and laboratory data in schools.

RESEARCH DESIGN AND METHODS

Anthropometric measurements and fasting and 2-h post-glucose load blood draws were obtained from approximately 1,740 eighth-grade students.

RESULTS

Mean recruitment rate was 50% per school, 49% had BMI > or = 85th percentile, 40.5% had fasting glucose > or = 100 mg/dl, 0.4% had fasting glucose > or = 126 mg/dl, and 2.0% had 2-h glucose > or = 140 mg/dl and 0.1% > or = 200 mg/dl. Mean fasting insulin value was 30.1 microU/ml, 36.2% had fasting insulin > or = 30 microU/ml, and 2-h mean insulin was 102.1 microU/ml. Fasting and 2-h glucose and insulin values increased across BMI percentiles, and fasting glucose was highest in Hispanic and Native American students.

CONCLUSIONS

There was a high prevalence of risk factors for diabetes, including impaired fasting glucose (> or =100 mg/dl), hyperinsulinism suggestive of insulin resistance (fasting insulin > or = 30 microU/ml), and BMI > or = 85th percentile. These data suggest that middle schools are appropriate targets for population-based efforts to decrease overweight and diabetes risk.

Genome-wide search for sarcoidosis susceptibility genes in African Americans

Sarcoidosis, a systemic granulomatous disease of unknown etiology, likely results from an environmental insult in a genetically susceptible host. In the US, African Americans are more commonly affected with sarcoidosis and suffer greater morbidity than Caucasians. We searched for sarcoidosis susceptibility loci by conducting a genome-wide, sib pair multipoint linkage analysis in 229 African-American families ascertained through two or more sibs with a history of sarcoidosis. Using the Haseman-Elston regression technique, linkage peaks with P-values less than 0.05 were identified on chromosomes 1p22, 2p25, 5p15-13, 5q11, 5q35, 9q34, 11p15 and 20q13 with the most prominent peak at D5S2500 on chromosome 5q11 (P=0.0005). We found agreement for linkage with the previously reported genome scan of a German population at chromosomes 1p and 9q. Based on the multiple suggestive regions for linkage found in our study population, it is likely that more than one gene influences sarcoidosis susceptibility in African Americans. Fine mapping of the linked regions, particularly on chromosome 5q, should help to refine linkage signals and guide further sarcoidosis candidate gene investigation.

A sarcoidosis genetic linkage consortium: the sarcoidosis genetic analysis (SAGA) study

BACKGROUND

Sarcoidosis, a systemic granulomatous disease of unknown etiology, likely results from an environmental insult in a genetically susceptible host. In the United States of America, African Americans have a higher sarcoidosis incidence and suffer greater morbidity than Caucasians.

METHODS

A sarcoidosis genetic linkage study consortium was established to recruit African-American affected sib pair (ASP) families to identify chromosomal regions that may harbor sarcoidosis susceptibility genes and to determine if environmental factors modify any genetic effects.

RESULTS

We successfully met our goal of enrolling 359 ASPs using a multifaceted recruitment approach. In the total 559 sib pairs that were enrolled, genetic analyses revealed incorrectly specified relationships that required reclassification or removal from the analysis dataset of 10.4% of reported full and 1.4% of reported half sib pairs. The final study sample comprised 415 full and 104 half sib pairs with complete data. This included 338 ASPs. Within sib pairs, affection status was not associated with sex. Only 15 per cent of the 229 families had three or more affected sibs, but they contributed 42 per cent of the ASP total.

CONCLUSIONS

The SAGA study experience should provide useful lessons and information to serve others in conducting genetic studies of complex diseases in African-American families.

VEGF gene transfer for diabetic neuropathy

Among diabetics, peripheral neuropathy is common and ultimately accounts for significant morbidity. The ultimate consequence of such sensory defects involving the lower extremities may be foot ulceration initiated by trauma that is inapparent to the patient. Such ulcerations often lead to lower extremity amputation, a complication that is 15 times higher in diabetic versus non-diabetic patients. Preliminary clinical studies have demonstrated improvement in signs and symptoms of sensory neuropathy in patients with lower extremity vascular occlusive disease following intramuscular injection of naked DNA encoding vascular endothelial growth factor (VEGF). To determine if such a strategy could be applied to diabetic patients, including those without evidence of large vessel occlusive disease, we investigated the hypothesis that experimental diabetic neuropathy results from destruction of the vasa nervorum and can be reversed by administration of an angiogenic growth factor. In two different animal models of diabetics, nerve blood flow and the number of vasa nervorum were found to be markedly attenuated resulting in severe peripheral neuropathy. In contrast, following VEGF gene transfer, vascularity and blood flow in nerves of treated animals were similar to those of non-diabetic controls; constitutive overexpression of VEGF resulted in restoration of large and small fiber peripheral nerve function. These findings implicate microvascular disruption as the basis for diabetic neuropathy and suggest that angiogenic growth factors may constitute a novel treatment strategy for this pernicious disorder. Accordingly, we now seek to address the following two objectives: 1. Objective #1: is to evaluate the safety and impact of phVEGF165 gene transfer on sensory neuropathy in patients with diabetes and associated macrovascular disease involving the lower extremities. 2. Objective #2: is to evaluate the safety and impact of phVEGF165 gene transfer on sensory neuropathy in patients with diabetes without macrovascular disease involving the lower extremities. The protocol outlined in this Investigational New Drug Application has been designed as a Phase I/II, single-site, dose escalating, double-blind, placebo controlled study to evaluate the safety and impact of phVEGF165 gene transfer on sensory neuropathy in patients with diabetes with or without macrovascular disease involving the lower extremities. Diabetic males or females > 21 years old with sensory neuropathy with or without macrovascular disease will be eligible. A total of 192 patients will be recruited into two arms of the study (each arm consisting of 96 patients) over a period of 4 years (the fifth year will be limited to follow-up examinations). The 96 patients in each of the two arms of the study will comprise 3 cohorts, each consisting of 32 patients. Within each of these cohorts, patients will be randomized to receive phVEGF165 or placebo based upon a 3:1 randomization ratio. Thus, at the completion of the study, 24 patients will have each received a given dose (1, 2, or 4 mg phVEGF165) and 24 patients will have received placebo. Doses will be employed in a serial dose-escalating fashion. The entire volume of the study drug will be divided and delivered in 8 intramuscular injections administered into the foot, calf muscle, or distal thigh muscle of the affected extremity. Following the initial set of injections, repeat treatment with an identical dose will be provided 2 and 4 weeks after initial treatment.

The use of hepatitis C viral RNA levels in liver tissue to distinguish rejection from recurrent hepatitis C

Persistence of hepatitis C virus (HCV) after orthotopic liver transplantation is almost universal in HCV-infected patients. Histological examination of liver biopsy specimens can be variable in distinguishing between recurrent hepatitis C and acute cellular rejection. The purpose of this study is to determine whether hepatic HCV RNA levels can be used to distinguish rejection from recurrent HCV by determining whether hepatic HCV RNA levels correlate with histological characteristics and clinical course. Seventy-two biopsy specimens were evaluated from 36 liver transplant recipients with HCV and elevated liver-related enzyme levels. Based on histological findings and clinical response to therapy, patients were defined as belonging to 1 of 5 groups: (1) definite rejection, (2) probable rejection, (3) indeterminate findings, (4) probable HCV, and (5) definite HCV. Hepatic HCV RNA was quantified using the Amplicor Monitor assay (Roche Diagnostic Systems Inc, Branchburg, NJ). There was a difference across groups in HCV RNA levels (P =.046). The median HCV RNA level was 10,695 copies/mg of tissue DNA in the definite-HCV group compared with 1,024 copies/mg of tissue DNA in the definite-rejection group. Using pairwise comparisons, significant differences were found between definite HCV and definite rejection, probable HCV and definite rejection, probable HCV and probable rejection, and probable HCV and indeterminate. Our findings support the following conclusions. (1) In liver transplant recipients, hepatic HCV RNA levels are statistically greater in patients with recurrent HCV than rejection, although there is considerable overlap between groups. (2) Patients with low HCV RNA levels were unlikely to have recurrent HCV. (3) Patients with minimal and indeterminate findings on biopsy (group 3) had low HCV RNA levels.

The Next Step Trial: impact of a worksite colorectal cancer screening promotion program

BACKGROUND

The Next Step Trial was a randomized trial of worksite colorectal cancer screening promotion and nutrition interventions for automobile industry employees at increased risk of colorectal cancer. Interventions were tested at 28 worksites with 5,042 employees. This report describes results of the screening promotion intervention.

METHODS

Worksites randomized to the control group received a standard program including rectal examination, fecal occult blood testing, and flexible sigmoidoscopy. Intervention worksites received an enhanced program (i.e., standard program plus an educational booklet/telephone call). Compliance (i.e., completion of all recommended screening examinations) and coverage (i.e., completion of at least one screening examination), the primary and secondary outcomes, were measured over 2 years.

RESULTS

In the 2 years prior to baseline, 61% of employees had been screened. After random assignment, baseline differences in several employee characteristics and worksite screening procedures were detected, including more past history of screening in control worksites. After adjusting for differences, we found modest, but higher, compliance and coverage in intervention compared with control worksites (odds ratio [95% confidence limits] = 1.46 [1.1-2.0] and 1.33 [1.1, 1.6], respectively).

CONCLUSIONS

Adding a personally tailored behavioral intervention to a standard colorectal cancer screening program can promote continued employee participation in screening as measured by compliance. Further research is needed to assess intervention effects in other populations.

Nutrition intervention for high-risk auto workers: results of the Next Step Trial

BACKGROUND

The Next Step Trial tested interventions encouraging prevention and early detection practices in automotive-industry employees at increased colorectal cancer risk. This article describes results of the nutrition intervention promoting low-fat, high-fiber eating patterns.

METHODS

Twenty-eight worksites (5,042 employees at baseline) were randomized to a 2-year nutrition intervention including classes, mailed self-help materials, and personalized dietary feedback. Control worksites received no intervention. Nutrition outcomes were assessed by mailed food frequency questionnaires (FFQs) Primary nutrition outcomes included percentage energy from fat and fiber density (g/1,000 kcal) at 1 year postrandomization. Secondary outcomes included servings of fruits/vegetables and dietary measures at 2 years postrandomization. Analyses were adjusted for within worksite correlations and baseline covariates. Fifty-eight percent of employees returned FFQs.

RESULTS

At 1 year, there were modest but statistically significant intervention effects for fat (-0.9 %en), fiber (+0.5 g/1,000 kcal), and fruits/vegetables (+0.2 servings/day) (all P < 0.007). At 2 years, due to significant positive changes in control worksites, intervention effects were smaller, significant for fiber only. Intervention effects were larger in younger (<50 years), active employees and class attendees.

CONCLUSION

The nutrition intervention produced significant but modest effects on dietary fat and fiber and fruits/vegetables in these high-risk employees. Age and dose effects suggest younger employees may be more responsive to this intervention.

Temporal profile of connexin 43 mRNA expression in a tetanus toxin-induced seizure disorder

The messenger ribonucleic acid (mRNA) of gap junction protein connexin 43 was quantified in the tetanus toxin rat model of focal epilepsy following injection of toxin into the left amygdala. Animals were monitored electrographically at weekly intervals with bilateral amygdala electrodes. Cohorts of 3 rats were sacrificed at weeks 1, 2, 3, 4, 6, 8, and 10, and bilateral regions containing the amygdala and posterior cerebral cortex were sampled, frozen, and later pooled for northern blot analysis. Spike generation was manifest in all animals during the first 4 wk followed by variable attenuation and cessation by 10 wk. Electrode implantation alone was shown by regression analysis to cause significant (p < 0.05) elevation of connexin mRNA in weeks 1-4. Injection of toxin diminished connexin mRNA expression in the amygdala when compared to electrode implantation alone. No trend in connexin mRNA expression was established over time in either amygdala or cerebral cortex in the acute epileptic or chronic postepileptic phase. No association between connexin 43 mRNA expression and the development of epileptogenicity was found in the context of a self-limiting animal model of focal epilepsy.

Psychosocial correlates of healthful diets among male auto workers

A better understanding of factors associated with healthful eating practices can improve the design and evaluation of dietary intervention programs. Up to now, little information has been available about these factors in high-risk but healthy populations. This article presents findings of a study of psychosocial factors, including stage of change, and their relationship to patterns of consumption of dietary fat, fiber, and fruits and vegetables in a population of males at increased risk of colorectal cancer. Data are from the baseline survey for the Next Step Trial, a randomized, controlled trial of worksite nutrition and colorectal cancer screening promotion interventions. The respondents (n = 2764) were actively employed or retired auto workers at increased colorectal cancer risk. The psychosocial constructs measured were predisposing factors (benefits, motivation, knowledge; eight items; Cronbach alpha = 0.50), enabling factors (barriers, norms, social support; six items; Cronbach alpha = 0.55), and stages of change for adopting diets lower in fat and higher in fiber/fruits and vegetables. The measures of diet, assessed with a food frequency questionnaire, were intakes of fat, fiber, and servings of fruits and vegetables. There were strong and statistically significant positive associations between both predisposing and enabling scale scores and stages of change for fat and fiber. The percentage of respondents in maintenance stage ranged from 4-80% for fat and 11-81% for fiber, across low to high predisposing scale scores; for enabling scale scores, ranges were 11-71% for fat and 22-81% for fiber. Stage of change was associated with fat, fiber, and fruit and vegetable intake in a stepwise manner, with the greatest change observed between action and maintenance. Correlations with dietary outcomes were significantly greater for predisposing factors (r = -0.30 for fat and 0.36 for fiber) than for enabling factors (r = -0.23 for fat and 0.28 for fiber). Multiple regression models, which included the predisposing and enabling factor scales, stage of change, and covariates related to diet, explained a total of between 16 and 27% of the variance in diet. Predisposing and enabling factors are significantly associated with of stage of change and current diet in this high-risk sample of male auto workers. Stage of change is the strongest correlate examined and seems to serve as a mediating factor for dietary change. Results from the Next Step Trial will provide additional data on whether and how health promotion interventions influence these factors, and whether such changes are associated with dietary change.

Bone mineral density and biochemical markers of bone turnover in healthy elderly men and women

BACKGROUND

Osteoporosis risk in middle-aged women is twofold greater than that in men, and the difference increases with age. Gender differences in bone mineral density, estimated rates of bone loss, and usefulness of markers of bone metabolism for predicting bone density have not been well described in healthy elders aged 65 and above. The purpose of this cross-sectional analysis was to describe associations of bone mineral density at the hip, spine, and whole body with age, serum osteocalcin, and urinary N-telopeptide crosslinks of Type I collagen in healthy elderly men and women.

METHODS

A total of 1,087 healthy adults (273 men and 814 women) aged 65 to 87 years were enrolled in a collaborative study at 3 sites: Tufts University (Boston, MA), University of Connecticut Health Center (Farmington, CT), and Creighton University (Omaha, NE). Bone mineral density (BMD) at three regions of the hip, the lumbar spine, and whole body was determined by dual-energy x-ray absorptiometry. Serum osteocalcin was measured by immunoassay, and measurement of N-telopeptide crosslinks (Ntx) in urine was made using an enzyme-linked radioimmunoassay (ELISA).

RESULTS

Among women, the age-related decline in BMD at all non-spine skeletal sites was significantly different from zero, with the largest decline seen at the femoral neck (-.0038 g/cm2/y, p < .001) and the smallest at the trochanter of the hip (-.0023 g/cm2/y, p = .03). Among men, the changes at all non-spine sites were not significant. In both sexes, spine BMD tended to increase with age (men, +.0045 g/cm2/y, women, +.0003 g/cm2/y). Serum osteocalcin and urinary Ntx were inversely related to BMD at all skeletal sites, but the weakest associations were observed at the spine. Individuals whose values of both osteocalcin and Ntx were in the lowest quartiles of the respective sex-specific distributions had mean femoral neck BMD that were 11% higher than individuals with marker values in the highest quartiles.

CONCLUSIONS

These findings suggest that age-related decreases in BMD may vary by gender and skeletal site. Determinations of osteocalcin and N-telopeptide crosslinks at a single point in time may potentially be used as indicators of current bone status, particularly at non-spine skeletal sites.

Worksite cancer screening and nutrition intervention for high-risk auto workers: design and baseline findings of the Next Step Trial

BACKGROUND

This article describes the design and baseline findings of The Next Step Trial, a health promotion intervention targeting automobile industry employees at increased colorectal cancer risk. The intervention encouraged colorectal cancer screening participation and adoption of low-fat, high-fiber diets.

METHODS

Twenty-eight worksites (n = 5,042) were randomized to control (a company-sponsored screening program) or intervention (an enhanced screening program including a personalized educational booklet and motivational telephone call and diet-change program including nutrition classes, self-help materials, and computer-generated personalized feedback). Outcomes included screening compliance and fat and fiber intake.

RESULTS

Pretrial data indicated targeted employees were predominantly older, well educated, married, Caucasian men. Sixty-one percent (SE = 2) participated in the screening program in the preceding 2 years, and 24% (SE = 1) reported a history of colorectal polyps or cancer. Fifty-eight percent of the cohort responded to the baseline questionnaire; respondents were older and more educated; more were married, retired, and Caucasian than nonrespondents. Mean dietary intakes were 36.9% energy from fat (SE = 0.21), 8.8 g fiber/1000 kcal (SE = 0.07), and 3.4 servings of fruits and vegetables per day (SE = 0.04).

CONCLUSIONS

Baseline data show moderate screening participation and dietary intakes that did not meet guidelines; hence intervention efforts were warranted. Data from this trial will support a rigorous test of whether this high-risk employee population is responsive to targeted health promotion, early cancer detection, and prevention interventions.

A generalized Michaelis-Menten response surface

We describe an application of recently developed generalized Michaelis-Menten response surface and non-linear mixed model methodologies to model glucose utilization in foetal sheep. More specifically, we model the response surface of glucose utilization rate in the foetal sheep as a function of glucose and insulin concentrations using a three-dimensional analogue of the Michaelis-Menten pharmacokinetic model. To account for multiple measurements per sheep, we apply the non-linear mixed effects model proposed by Lindstrom and Bates using the EM algorithm computational scheme presented by Hirst et al.

The transcription factor, the Cdk, its cyclin and their regulator: directing the transcriptional response to a nutritional signal

The Pho80-Pho85 cyclin-cdk complex prevents transcription of PHO5 by inhibiting the ability of the basic-helix-loop-helix transcription factor Pho4 to activate transcription in response to high phosphate conditions. In low phosphate the Pho80-Pho85 complex is inactivated and Pho4 is then able to activate the acid phosphatase gene PHO5. We show here that Pho4 and the homeobox protein Pho2 interact in vivo and act cooperatively to activate the PHO5 UAS, with interaction being regulated by the phosphate switch. In addition, we also demonstrate that an additional factor, Pho81, interacts in high phosphate with both the Pho80 cyclin and with Pho4. In low phosphate, Pho80 and Pho81 dissociate from Pho4, but retain the ability to interact with each other. The evidence presented here supports the idea that Pho81 acts as a phosphate-sensitive trigger that regulates the ability of the Pho80-Pho85 cyclin-cdk complex to bind Pho4, while DNA binding by Pho4 is dependent on the phosphate-sensitive interaction with Pho2.

Gender differences in lipid alterations following combined pancreas-kidney transplantation

We have previously demonstrated that the lipid profile improves following successful combined pancreas-kidney transplantation (PKT). In this study, we examined whether changes in the lipid profile were different in men than in women following PKT. Fasting total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL), and the TC to HDL ratio (TC/HDL) were evaluated in 47 patients (27 men and 20 women) with normal graft function following PKT. Lipids were evaluated at regular intervals 3.5 months to 2.2 years post-PKT (a total of 317 observations). After PKT, TC/HDL decreased (P < .05), TC was unchanged, and HDL increased (P < .05) in both men and women. Although TG decreased in both men and women, it reached statistical significance in men only (P < .05). There were no significant differences in any lipid parameters between men and women before PKT, but after PKT, TC, TG, and HDL were higher in women (240 +/- 11, 183 +/- 17, and 64 +/- 19 mg/dL, respectively) than in men (207 +/- 6, 143 +/- 11, and 53 +/- 2 mg/dL, P < .05 for each). When post-PKT values were analyzed for trends over time, both TC and TG decreased (P < .05 for both) without any significant difference in trends between men and women. When six individuals who had received lovastatin at any time during their postoperative course were removed from analysis, the gender differences in TG post-PKT and the decrease in TG over time were no longer statistically significant (P > .05).(ABSTRACT TRUNCATED AT 250 WORDS)

The activation domain of a basic helix-loop-helix protein is masked by repressor interaction with domains distinct from that required for transcription regulation

While there are many examples of protein-protein interactions modulating the DNA-binding activity of transcription factors, little is known of the molecular mechanisms underlying the regulation of the transcription activation function. Using a two-hybrid system we show here that transcription repression of the basic domain/helix-loop-helix factor PHO4 is mediated by complex formation with the PHO80 repressor. In contrast to other systems, such as inhibition of GAL4 by GAL80 or of p53 by MDM2, where repression is mediated by direct interaction at regions overlapping the transcription activation domain, interaction with PHO80 involves two regions of PHO4 distinct from those involved in transcription activation or DNA-binding and dimerization. The possibility that repression of PHO4 by PHO80 may represent a general mechanism of transcription control, including regulation of the cell-type-specific transcription activation domain of c-Jun, is discussed.

Frozen section evaluation of donor livers before transplantation

Frozen section examination was performed on 385 donor livers before transplantation. Exclusion criteria were applied to the donor livers examined to exclude potentially dysfunctional livers. The exclusion criteria included the following: severe macrovesicular steatosis, ischemic necrosis, prominent chronic portal inflammation, prominent periductular fibrosis, granulomatous inflammation, bridging fibrosis, and malignancy. Twenty-seven of the 385 donor livers examined were excluded before transplantation. The following histologic features were present in the excluded livers: severe steatosis (22), ischemic necrosis (2), portal inflammation (1), and periductular fibrosis (2). Steatosis was present in 51 of the 385 (13.25%) organs examined, including 22 of the donor organs excluded before transplantation. Twenty-nine livers with mild to moderate steatosis were implanted into size and blood type-matched recipients. Indicators of allograft function (prothrombin time and bilirubin) and damage (aspartate aminotransferase and alanine aminotransferase) were measured daily for the first 10 days after transplant. There was no statistically significant difference between the group of nonfat livers and donor livers containing mild steatosis. Statistically significant higher posttransplant serum alanine aminotransferase and prothrombin time levels were present in the patients with livers implanted with mild versus moderate steatosis. The 1-year survival rate for patients receiving fatty versus nonfatty donor livers was not statistically different (Kaplan-Meier, P = 0.592). No significant differences were found in the clinical and laboratory characteristics of donors whose organs were implanted compared with the clinical and laboratory characteristics of donors whose organs were excluded. The primary nonfunction rate after applying the exclusion criteria was 1.4%, which is a significant decrease compared with our primary nonfunction rate of 8.5% before using frozen section examination. Frozen section examination is useful in excluding donor organs which may become dysfunctional after transplantation.

Lipid status after combined pancreas-kidney transplantation and kidney transplantation alone in type I diabetes mellitus

This study was designed to compare changes in lipid status following organ transplantation between type I diabetes mellitus (DM-I) patients receiving combined pancreas-kidney transplantation (PKT) with those receiving kidney transplantation alone (KTA). A retrospective chart review was used to identify pre- and posttransplantation fasting total cholesterol (TC) and triglycerides (TG) in three groups: DM-I patients receiving KTA (DM:KTA; n = 14), DM-I patients receiving PKT (DM:PKT; n = 20), and kidney transplant recipients without DM (NDM; n = 16). The groups were matched for age, gender, weight, duration of dialysis, smoking history, and duration of diabetes mellitus. Linear regression was used to analyze differences in lipid trends over time (up to 24 months posttransplantation) and the effects of prednisone dose, cyclosporine dose, and serum creatinine. Preoperative TC was significantly lower in the DM:KTA group (P < 0.05) compared with DM:PKT or NDM. There were no significant differences in preoperative TG between the three groups. TC and TG decreased over time only in DM:PKT (P = 0.0112, P = 0.0278, respectively). TC increased and TG was unchanged over time in DM:KTA (P = 0.0003, P = 0.1103, respectively). Neither TC nor TG changed over time in NDM. Trends of TC and TG for DM:PKT were significantly different from DM:KTA (P < 0.01 for both). Trend of TC for NDM was also significantly different from DM:PKT (P = 0.0061). Prednisone dose was significantly related to TC in DM:KTA and NDM (P < 0.01) while cyclosporine dose was significantly related to TC for DM:KTA only (P = 0.0013) in the presence of time. None of the variables tested (prednisone dose, cyclosporine dose, and serum creatinine) significantly affected TG in the presence of time. In summary, TC and TG decreased over time only in DM:PKT. In contrast, TC increased while TG was unchanged in DM:KTA over the same interval (0-24 months). If these trends continue, the beneficial change in lipids in the DM:PKT group may translate into a net improvement in atherosclerosis-mediated events for diabetic patients with chronic renal failure who receive PKT compared with those who do not.

Authentic temperature-regulation of a heat shock gene inserted into yeast on a high copy number vector. Influences of overexpression of HSP90 protein on high temperature growth and thermotolerance

Heat shock protein HSP90 is relatively abundant in eukaryotic cells even in the absence of heat shock. Its precise function is still unclear, although it is apparently required in higher levels for growth at high temperatures. In this study Saccharomyces cerevisiae transformants were constructed with 50-150 copies of the homologous heat-inducible gene for HSP90 (HSP82) present on a high copy number episomal vector. These transformants were then used to demonstrate: (i) that this heat shock gene displays essentially normal regulation when present in yeast at high copy numbers; (ii) that yeast is an expression host suitable for the high level synthesis of HSP90; and (iii) that increasing normal cellular levels of HSP90 affects a number of physiological properties. The HSP82 gene is normally single-copy in the haploid yeast genome, yet even at 50 to 150 copies per cell it displayed almost normal basal and heat shock-induced levels of expression. Proper regulation of the heat shock element sequence controlling HSP82 is therefore not lost at high gene copy levels. In unstressed cultures in exponential growth at 25 degrees C the low basal expression of the multiple HSP82 gene copies caused a 3 to 7-fold HSP90 overproduction, but HSP90 levels increased 10-fold to 30-40% of total cell protein following temperature upshift to 39 degrees C for 75 min. Heat induction of the chromosomal genes for other heat shock proteins in the same cells was not suppressed relative to cells which were isogenic but for the possession of just a single HSP82 gene, this constituting further evidence that yeast can authentically regulate a large number of heat shock genes. HSP90 overproduction was not protective against heat killing, causing strain-dependent reductions in growth at 37.5 degrees C and in thermotolerance.

Starvation for His-tRNAHis in yeast causes translational arrest without a high level of misincorporation of glutamine at histidine codons

The hts1.1 temperature-sensitive histidinyl-tRNA synthetase mutation enables Saccharomyces cerevisiae to be starved for His-tRNAHis by upshift to the non-permissive temperature of 38 degrees C. If yeast behaves similarly to bacterial and mammalian cells, this lack of His-tRNAHis should greatly enhance misreading at histidine codons (CAU/CAC) by Gln-tRNAGln, resulting in substitution of the neutral amino acid glutamine in place of histidine, a basic amino acid. Such misreading causes the isoelectric point (pI) of proteins to shift to lower values, and is readily detectable as "stuttering" on two-dimensional (2D) protein gels. By gel analysis of pulse-labelled proteins of hts1.1 yeast cells that were overexpressing phosphoglycerate kinase (PGK), our study sought to detect this specific translational error in PGK protein. It was not detected by this relatively sensitive technique, indicating that missense errors due to glutamine insertion at histidine codons do not occur in yeast at the readily-detectable level found in bacterial and mammalian cells.

Plasma and erythrocyte amino acids in mother and fetus

Plasma (P) and whole blood (WB) amino acid concentrations were measured in arterial and venous blood of 9 mothers and their fetuses at elective cesarean section and compared to values obtained in 5 normal nonpregnant women. Erythrocyte (E) amino acid concentrations were calculated from P and WB concentrations. E/P ratios were significantly greater than 1.0 in all groups studied. Alanine, glycine, and serine presented E/P ratios significantly higher in pregnant women than in control nonpregnant women. Fetuses presented significantly lower E/P ratios for lysine than pregnant and nonpregnant women. Uterine arteriovenous amino acid differences were not significantly different from zero in both plasma and erythrocytes. Umbilical venous-arterial differences were significantly positive for most essential amino acids in plasma, whereas they were not significantly different from zero in erythrocytes. This finding suggests that erythrocytes do not play a major role in the transfer of amino acids from the placenta to the fetus.

Fetal hind limb oxygen consumption and blood flow during acute graded hypoxia

Hind limb blood flow and O2 uptake, mean blood pressure, and heart rate were measured in six fetal sheep at 127-141 d gestation in the control state and at different levels of hypoxia that were induced by partial occlusion of the maternal terminal aorta. Blood flow was measured by an ultrasonic flow transducer. Control fetal arterial O2 content ([O2]a) in the descending aorta was 3.25 + 0.17 mM. In response to graded acute hypoxia, blood flow first increased (22.2 versus 19.9 mL.min-1.100 g-1, p = 0.003) and then decreased abruptly at approximately 1.5 mM [O2]a.O2 uptake decreased about 12% (14.74 versus 16.71, p = 0.03) as [O2]a decreased to 1.5 mM, and then fell markedly, tending toward zero for [O2]a = 0.9 mM. In the 2.7- to 1.5-mM [O2]a range, heart rate increased above control (194 versus 169 min-1, p = 0.0024), whereas mean blood pressure did not change significantly. For [O2]a less than 1.5 mM, heart rate decreased to 148 min-1 (p = 0.0005) and mean blood pressure increased above baseline (55 versus 47 torr, p = 0.0001). In conjunction with previous evidence, these results define a state of acute moderate hypoxia in which the whole fetus can sustain a relatively high rate of oxidative metabolism, and a state of acute severe hypoxia ([O2]a between 1.5 and 1.0 mM) in which O2 uptake by some fetal organs is selectively and markedly decreased.