Control of endodermal endocrine development by Hes-1

Development of endocrine cells in the endoderm involves Atonal and Achaete/Scute-related basic helix-loop-helix (bHLH) proteins. These proteins also serve as neuronal determination and differentiation factors, and are antagonized by the Notch pathway partly acting through Hairy and Enhancer-of-split (HES)-type proteins. Here we show that mice deficient in Hes1 (encoding Hes-1) display severe pancreatic hypoplasia caused by depletion of pancreatic epithelial precursors due to accelerated differentiation of post-mitotic endocrine cells expressing glucagon. Moreover, upregulation of several bHLH components is associated with precocious and excessive differentiation of multiple endocrine cell types in the developing stomach and gut, showing that Hes-1 operates as a general negative regulator of endodermal endocrine differentiation.

Expression of specific chemokines and chemokine receptors in the central nervous system of multiple sclerosis patients

Chemokines direct tissue invasion by specific leukocyte populations. Thus, chemokines may play a role in multiple sclerosis (MS), an idiopathic disorder in which the central nervous system (CNS) inflammatory reaction is largely restricted to mononuclear phagocytes and T cells. We asked whether specific chemokines were expressed in the CNS during acute demyelinating events by analyzing cerebrospinal fluid (CSF), whose composition reflects the CNS extracellular space. During MS attacks, we found elevated CSF levels of three chemokines that act toward T cells and mononuclear phagocytes: interferon-gamma-inducible protein of 10 kDa (IP-10); monokine induced by interferon-gamma (Mig); and regulated on activation, normal T-cell expressed and secreted (RANTES). We then investigated whether specific chemokine receptors were expressed by infiltrating cells in demyelinating MS brain lesions and in CSF. CXCR3, an IP-10/Mig receptor, was expressed on lymphocytic cells in virtually every perivascular inflammatory infiltrate in active MS lesions. CCR5, a RANTES receptor, was detected on lymphocytic cells, macrophages, and microglia in actively demyelinating MS brain lesions. Compared with circulating T cells, CSF T cells were significantly enriched for cells expressing CXCR3 or CCR5. Our results imply pathogenic roles for specific chemokine-chemokine receptor interactions in MS and suggest new molecular targets for therapeutic intervention.

Rapid healing of venous ulcers and lack of clinical rejection with an allogeneic cultured human skin equivalent. Human Skin Equivalent Investigators Group

OBJECTIVE

To test the safety, efficacy, and immunological impact of a cultured allogeneic human skin equivalent (HSE) in the treatment of venous ulcers.

DESIGN

Prospective, randomized study.

SETTING

Multicenter study in the outpatient setting.

INTERVENTION

Each patient with a venous ulcer received either compression therapy alone or compression therapy and treatment with HSE. The patients were evaluated for HSE safety, complete (100%) ulcer healing, time to wound closure, wound recurrence, and immune response to the HSE.

OUTCOME

The study was completed as planned in 293 randomized patients.

RESULTS

Treatment with HSE was more effective than compression therapy in the percentage of patients healed by 6 months (63% vs 49%; P=.02, Fisher exact test, 2-tailed) and the median time to complete wound closure (61 days vs 181 days; P=.003, log-rank test). Treatment with HSE was superior to compression therapy in healing larger (> 1000 mm2; P=.02) and deeper ulcers (P=.003) and ulcers of more than 6 months' duration (P=.001). Occurrence of adverse events was similar in both groups. No symptoms or signs of rejection occurred in response to treatment with HSE, and no HSE-specific immune responses were detected in vitro to bovine collagen or to alloantigens expressed on keratinocytes or fibroblasts.

CONCLUSIONS

Treatment with HSE healed venous ulcers more rapidly and in more patients than compression therapy alone. There was no clinical or laboratory evidence of rejection or sensitization in response to HSE application. These data suggest that HSE represents a significant advance in the treatment of venous ulcers, particularly those that are difficult to heal.

Independent development of pancreatic alpha- and beta-cells from neurogenin3-expressing precursors: a role for the notch pathway in repression of premature differentiation

The nature and identity of the pancreatic beta-cell precursor has remained elusive for many years. One model envisions an early multihormonal precursor that gives rise to both alpha- and beta-cells and the other endocrine cell types. Alternatively, beta-cells have been suggested to arise late, directly from the GLUT2- and pancreatic duodenal homeobox factor-1 (PDX1)-expressing epithelium, which gives rise also to the acinar cells during this stage. In this study, we have identified a subset of the PDX1+ epithelial cells that are marked by expression of Neurogenin3 (Ngn3). Ngn3, a member of the basic helix-loop-helix (bHLH) family of transcription factors, is suggested to act upstream of NeuroD in a bHLH cascade. Detailed analysis of Ngn3/paired box factor 6 (PAX6) and NeuroD/PAX6 co-expression shows that the two bHLH factors are expressed in a largely nonoverlapping set of cells, but such analysis also suggests that the NeuroD+ cells arise from cells expressing Ngn3 transiently. NeuroD+ cells do not express Ki-67, a marker of proliferating cells, which shows that these cells are postmitotic. In contrast, Ki-67 is readily detected in Ngn3+ cells. Thus, Ngn3+ cells fulfill the criteria for an endocrine precursor cell. These expression patterns support the notion that both alpha- and beta-cells develop independently from PDX1+/Ngn3+ epithelial cells, rather than from GLU+/INS+ intermediate stages. The earliest sign of alpha-cell development appears to be Brain4 expression, which apparently precedes Islet-1 (ISL1) expression. Based on our expression analysis, we propose a temporal sequence of gene activation and inactivation for developing alpha- and beta-cells beginning with activation of NeuroD expression. Endocrine cells leave the cell cycle before NeuroD activation, but re-enter the cell cycle at perinatal stages. Dynamic expression of Notch1 in PDX+ epithelial cells suggests that Notch signaling could inhibit a Ngn-NeuroD cascade as seen in the nervous system and thus prevent premature differentiation of endocrine cells.

Cigarette smoking, serum estrogens, and bone loss during hormone-replacement therapy early after menopause

To elucidate the effect of smoking on estrogen metabolism, we examined 136 postmenopausal women treated for one year with one of three different doses of combined estrogen-progestogen or placebo. The women were grouped according to smoking status, and serum levels of estrone and estradiol were measured before and after treatment. The results showed reduced levels of both estrogens in smokers as compared with nonsmokers in all three dosage groups. This reduction was most pronounced in the high-dose group (4 mg of estradiol), in which the serum levels of estrone and estradiol in smokers were only 50 per cent of those in nonsmokers (P less than 0.001 and less than 0.05, respectively). In contrast, no significant changes could be demonstrated in the corresponding placebo groups. Moreover, it was possible to demonstrate significant inverse correlations between the number of cigarettes smoked daily and the changes in the levels of serum estrone and estradiol, respectively, (P less than 0.001). This study suggests that an increased hepatic metabolism of estrogens results in lower estrogen levels among postmenopausal smokers. This may contribute to the reported risk of osteoporosis among smokers.

Urinary albumin excretion. An independent predictor of ischemic heart disease

Cross-sectional studies suggest that an increased urinary albumin excretion rate is associated with cardiovascular disease, dyslipidemia, and hypertension. The purpose of this study was to analyze prospectively whether the urinary albumin-to -creatinine (A/C) ratio can independently predict ischemic heart disease (IHD) in a population-based cohort. In 1983, urinary albumin and creatinine levels were measured, along with the conventional atherosclerotic risk factors, in 2085 consecutive participants without IHD, renal disease, urinary tract infection, or diabetes mellitus. The participants were followed up until death, emigration, or December 31, 1993. IHD was defined as a hospital discharge diagnosis or cause of death including the diagnoses ICD-8 and 410 to 414. Seventy-nine individuals developed IHD during the 21 130 person-years of follow-up. They were characterized by a preponderance of males and higher age, body mass index, blood pressure, lipoproteins, and proportion of current smokers. Microalbuminuria was defined as an A/C ratio) >90 percentile (>0.65 mg/mmol). When adjusted for other risk factors, the relative risk of IHD associated with microalbuminuria was 2.3 (95% CI, 1.3 to 3.9, P=0.002), and the 10-year disease-free survival decreased from 97% to 91% (P<0.0001) when microalbuminuria was present. An interaction between microalbuminuria and smoking was observed, and the presence of microalbuminuria more than doubled the predictive effect of the conventional atherosclerotic risk factors for development of IHD. It is concluded that microalbuminuria is not only an independent predictor of IHD but also substantially increases the risk associated with other established risk factors.

Arterial hypertension, microalbuminuria, and risk of ischemic heart disease

Albumin excretion in urine is positively correlated with the presence of ischemic heart disease and atherosclerotic risk factors. We studied prospectively whether a slight increase of urinary albumin excretion, ie, microalbuminuria, adds to the increased risk of ischemic heart disease among hypertensive subjects. In 1983 and 1984, blood pressure, urinary albumin/creatinine concentration ratio, plasma total and HDL cholesterol levels, body mass index, and smoking status were obtained in a population-based sample of 2085 subjects, aged 30 to 60 years, who were free from ischemic heart disease, diabetes mellitus, and renal or urinary tract disease. Untreated arterial hypertension or borderline hypertension was present in 204 subjects, who were followed until 1993 by the National Hospital and Death Certificate Registers with respect to development of ischemic heart disease. During 1978 person-years, 18 (9%) of the hypertensive subjects developed ischemic heart disease. Microalbuminuria, defined as a urinary albumin/creatinine ratio above the upper decile (1.07 mg/mmol), was the strongest predictor of ischemic heart disease, with an unadjusted relative risk of 4.2 (95% CI 1.5 to 11.9, P=0.006) and a relative risk of 3.5 (95% CI 1.0 to 12.1, P=0.05) when adjusted for all other atherosclerotic risk factors, including age and gender. In conclusion, microalbuminuria confers a 4-fold increased risk of ischemic heart disease among hypertensive or borderline hypertensive subjects. Urinary albumin excretion should be measured regularly in a hypertension clinic, and a rigorous control of blood pressure and of other atherosclerotic risk factors is recommended in hypertensive patients with microalbuminuria.

Effects of testosterone replacement therapy in old hypogonadal males: a preliminary study

OBJECTIVE

To examine the effects of testosterone administration to older hypogonadal males (bioavailable testosterone less than 70 ng/dL).

DESIGN

Alternate-case controlled trial.

SETTING

St. Louis University.

PATIENTS

Eight males (mean age 77.6 +/- 2.3 years) who received testosterone and six males (mean age 76 +/- 2.3 years) who served as controls. Selected from alumni of the SHEP trial and attendees at the St. Louis University Impotence Clinic.

INTERVENTIONS

Testosterone enanthate (200 mg/mL) was administered intramuscularly to the treatment group every 2 weeks for 3 months.

MEASUREMENTS

Serum testosterone, bioavailable testosterone and estradiol, weight, % body fat, right hand muscle strength, balance, cholesterol, HDL-cholesterol, hematocrit, BUN, creatinine, albumin, calcium, PTH, 25(OH) vitamin D, 1,25(OH)2 vitamin D, osteocalcin, prostate-specific antigen, and fructosamine.

RESULTS

Males who received testosterone had a significant increase in testosterone and bioavailable testosterone concentration, hematocrit, right hand muscle strength and osteocalcin concentration. They had a decrease in cholesterol (without a change in HDL-cholesterol) levels and decreased BUN/Creatinine ratios.

CONCLUSION

These preliminary findings support the need for long term studies of testosterone therapy in older hypogonadal males.

Transcription factor hepatocyte nuclear factor 6 regulates pancreatic endocrine cell differentiation and controls expression of the proendocrine gene ngn3

Hepatocyte nuclear factor 6 (HNF-6) is the prototype of a new class of cut homeodomain transcription factors. During mouse development, HNF-6 is expressed in the epithelial cells that are precursors of the exocrine and endocrine pancreatic cells. We have investigated the role of HNF-6 in pancreas differentiation by inactivating its gene in the mouse. In hnf6(-/-) embryos, the exocrine pancreas appeared to be normal but endocrine cell differentiation was impaired. The expression of neurogenin 3 (Ngn-3), a transcription factor that is essential for determination of endocrine cell precursors, was almost abolished. Consistent with this, we demonstrated that HNF-6 binds to and stimulates the ngn3 gene promoter. At birth, only a few endocrine cells were found and the islets of Langerhans were missing. Later, the number of endocrine cells increased and islets appeared. However, the architecture of the islets was perturbed, and their beta cells were deficient in glucose transporter 2 expression. Adult hnf6(-/-) mice were diabetic. Taken together, our data demonstrate that HNF-6 controls pancreatic endocrine differentiation at the precursor stage and identify HNF-6 as the first positive regulator of the proendocrine gene ngn3 in the pancreas. They also suggest that HNF-6 is a candidate gene for diabetes mellitus in humans.

The epidemiology of fractures of the proximal humerus

Sevenhundred and thirty proximal humeral fractures, taken from a 5-year period, were entered in this study. We found a higher total incidence rate than that previously seen: 73/100,000 population. Twenty-nine percent of the patients required hospitalization; 75% of these were over 60 years old. Only 21% of these were operated on, the majority of admissions being for social reasons. A total of 583 bed-days were used each year in the Aarhus City area (250,000 inhabitants). The majority of fractures resulted from falls on level ground. The elderly fell at home, while the younger people fell in public areas. Traffic accidents and work accidents were seldom seen. The accidents occurred typically around midday and before midnight, and mostly in December and January. Half of the fractures were two-part fractures of the surgical neck, while fractures of the greater tubercle and three-part fractures accounted for 21% and 17%, respectively. Based on current developments in the population average life span, it can be expected that proximal fractures will increase the hospital workload significantly in the future.

Influence of diabetes and hyperglycaemia on infectious disease hospitalisation and outcome

AIMS/HYPOTHESIS

Diabetes mellitus is believed to increase susceptibility to infectious diseases. The effects of hyperglycaemia per se on infectious disease risk are unknown and the influence of diabetes on infectious disease outcome is controversial.

MATERIALS AND METHODS

We studied 10,063 individuals from the Danish general population, who were participants in The Copenhagen City Heart Study, over a follow-up period of 7 years. Risk of hospitalisation caused by any infectious disease, and subsequent risk of disease progression to death were estimated by Cox proportional hazards regression analysis.

RESULTS

At baseline, 353 individuals reported having diabetes. During 71,509 person-years of follow-up, a total of 1,194 individuals were hospitalised because of an infection. The risk of pneumonia (adjusted hazard ratio [aHR] 1.75, 95% CI 1.23-2.48), urinary tract infection (aHR 3.03, 95% CI 2.04-4.49) and skin infection (aHR 2.43, 95% CI 1.49-3.95) was increased in subjects with diabetes compared with subjects without. Each 1 mmol/l increase in plasma glucose at baseline was associated with a 6-10% increased relative risk of pneumonia, urinary tract infection and skin infection after adjustment for other possible confounders. Among patients hospitalised for urinary tract infection, diabetic patients were at an increased risk of death at 28 days after admission compared with non-diabetic subjects (HR 3.90, 95% CI 1.20-12.66).

CONCLUSIONS/INTERPRETATION

In the Danish general population, diabetes and hyperglycaemia are strong and independent risk factors for hospitalisation as a result of pneumonia, urinary tract infection and skin infection. Further, diabetes has a negative impact on the prognosis of urinary tract infection.

Screening for somatization and hypochondriasis in primary care and neurological in-patients: a seven-item scale for hypochondriasis and somatization

The aim of this study was to investigate the internal and external validity of the Whiteley Index as a screening instrument for somatization illness. A 14-item version of the Whiteley Index for hypochondriacal traits was given to 99 of 191 consecutive primary care patients, aged 18-65 years, and to 100 consecutive patients, aged 18-60 years, admitted for the first time to a neurological ward. The primary care sample was, in addition, interviewed by means of the SCAN (Schedules for Clinical Assessment in Neuropsychiatry) psychiatric interview. The GPs and the neurologists were asked to rate various characteristics of the patients that might indicate somatization. The internal validity of the Whiteley Index was tested by means of latent structure analysis. On this basis, a reduced seven-item scale (Whiteley-7 scale) and two subscales (i.e., an Illness Conviction and Illness Worrying scale, each with three items) were constructed. All three had a high internal validity fitting into the very restricted Rasch statistical model (p>0.05) and an acceptable transferability between most of the subpopulations investigated. In the primary care population, the Whiteley-7 and the Illness Conviction scales at cut-point 0/1 showed 1.00 and 0.87 sensitivity and 0.65 and 0.87 specificity, respectively, using as "gold standard" the fulfillment of criteria for at least one ICD-10 somatoform disorder, and 0.71 and 0.63 sensitivity and 0.62 and 0.87 specificity, respectively, as gold standard for the fulfillment of criteria for at least one DSM-IV somatoform disorder, excluding the NOS diagnostic group. The Illness Worrying subscale showed less impressive performance in this respect. The agreement between the Whiteley-7 scale including the two subscales and neurologists' rating and the GPs' rating and the somatization subscale on the SCL-90 was modest or worse. It may be concluded that the Whiteley-7 scale and the Illness Conviction subscale had acceptable psychometric profiles, and both seem to be promising screening tools for not only hypochondriasis but also for somatoform disorders in general.

B cell origin of non-T cell acute lymphoblastic leukemia. A model for discrete stages of neoplastic and normal pre-B cell differentiation

The expression of B cell associated and restricted antigens on tumor cells isolated from 138 patients with non-T cell acute lymphoblastic leukemia (non-T cell ALL) was investigated by flow cytometric analysis by means of a panel of monoclonal antibodies. Tumor cells from these patients could be assigned to one of four subgroups: human leukocyte antigen-DR-related Ia-like antigens (Ia) alone (4%, stage I); IaB4 (14%, stage II); IaB4CALLA (33%, stage III); and IaB4CALLAB1 (49%, stage IV). The expression of B cell-restricted antigens (B4 and B1) and rearrangements of Ig heavy chain genes provided strong evidence for the B cell lineage of stages II, III, and IV tumors. The lineage of the Ia alone group is still unknown. The B4 antigen was expressed on approximately 95% of all non-T cell ALLs tested, and given its absence on T cell and myeloid tumors, it appears to be an exceptional marker to define cells of B lineage. The demonstration that Ia alone, IaB4, IaB4CALLA, and IaB4CALLAB1 positive cells can be readily identified by dual fluorescence analysis in normal fetal and adult bone marrow provided critical support for the view that these leukemic pre-B cell phenotypes were representative of the stages of normal pre-B cell differentiation. It was interesting that the IaB4+ cell was more frequently identified in fetal bone marrow than in adult marrow, whereas the predominant cell found in adult marrow expressed the IaB4CALLAB1 phenotype. These data suggest that the leukemogenic event may be random, since the predominant pre-B cell leukemic phenotype appears to correspond to the normal pre-B cell phenotype present in these hematopoietic organs. Our observations provide an additional distinction between adult and childhood ALL, since these studies show that most non-T cell ALLs seen in children less than 2 yr old are of stage II phenotype, whereas the majority of non-T ALLs in adults are of stage IV phenotype. Finally, it should be noted that the present study suggests that the analysis of leukemic B cell phenotypes and their normal counterparts can provide a mechanism for the investigation and orderly definition of stages of pre-B cell differentiation in man.

Is diabetic nephropathy an inherited complication?

For yet unidentified reasons less than 50% of patients with insulin-dependent mellitus develop diabetic nephropathy. Genetic factors have been suggested as risk markers for development of nephropathy in diabetes. To further evaluate this hypothesis we studied the prevalence of nephropathy in diabetic siblings of diabetic patients with and without nephropathy. From a representative sample of 619 patients with insulin-dependent diabetes, we identified 20 patients with and 29 patients without nephropathy having diabetic siblings. Diabetic nephropathy (defined as urinary albumin excretion greater than 300 mg/24 hr) was found in 7 out of 21 siblings to patients with nephropathy and 3 out of 30 siblings to normoalbuminuric patients (P less than 0.04). No significant differences between the two groups of siblings with respect to age, diabetes duration, sex distribution, blood pressure or glycosylated hemoglobin A1c-levels were found. A significant correlation within sib-pair of glycosylated hemoglobin A1c was found (r = 0.47; P less than 0.001). We conclude that familial clustering of diabetic nephropathy does occur. This clustering may either be due to genetic inheritance or to sib-similarities due to shared environment, as indicated by the correlation of glycosylated hemoglobin A1c within sib-pairs.

Prospective, randomized, endoscopic-blinded trial comparing precolonoscopy bowel cleansing methods

PURPOSE

Recent reports have suggested that precolonoscopy bowel preparation is easier to tolerate if a small volume solution is used. Therefore, the aim of this study was to compare three oral solutions for colonoscopy to determine any changes in either patient compliance or cleansing ability.

METHODS

Four hundred fifty patients were prospectively randomized to receive either a standard 4-liter polyethylene glycol solution, a newer sulfate-free 4-liter polyethylene glycol solution, or a 90-ml oral sodium phosphate preparation. Before and after bowel preparation all patients were weighed, and serum electrolytes as well as phosphate, magnesium, calcium, and osmolarity were measured. In addition, a detailed questionnaire was used to assess side effects and patient satisfaction. Endoscopists blinded to the type and quantity of preparation used scored the type of residual stool and the percentage of bowel wall visualized for each segment of colon and for the overall examination. Nurses recorded all procedure times as well as the quantity of irrigation and aspiration.

RESULTS

Four hundred twenty-two age-matched and sex-matched patients completed all phases of the trial. There were no clinically significant changes in weight or in any biochemical parameters. There was, however, asymptomatic hyperphosphatemia in the sodium phosphate group (P < 0.01). The length of time to the cecum was similar for all three groups, with a higher volume of fluid suctioned for sodium phosphate (P < 0.01). Overall, endoscopists scored sodium phosphate as "excellent" or "good" in 90 percent vs. 70 percent and 73 percent after the polyethylene glycol or sulfate-free lavage, respectively (P < 0.01). Particulate or solid stool was found in all segments of the colon more frequently after both large volume preparations than after sodium phosphate (P < 0.05). There were no significant differences in the frequency or intensity of any of the 11 side effects questioned. Eighty-three percent of the patients who received the sodium phosphate preparation stated they would take this same preparation again, vs. only 19 percent and 33 percent for polyethylene glycol and the sulfate-free lavage, respectively (P < 0.01).

CONCLUSION

The smaller volume oral sodium phosphate was not associated with any clinically significant problem, caused no increase in the incidence of side effects, was preferred by patients, and was more effective in colonic cleansing. However, the hyperphosphatemia seen may limit its use in patients with impaired renal function.

Autogenous mandibular bone grafts and osseointegrated implants for reconstruction of the severely atrophied maxilla: a preliminary report

The purpose of this study is to present results obtained with a new procedure for reconstruction of the severely atrophied maxillary alveolar ridge that involves the use of intramembranous corticocancellous bone grafts obtained from the mandibular symphysis fixed to the residual bone by endosseous implants. A total of 107 implants were installed in grafted regions in 26 patients. The follow-up period ranged from 6 to 32 months, with a mean of 16 months. In partially edentulous patients the bone grafts were fixed with implants to the residual bone as 1) onlay graft to the alveolar ridge (8 implants in 4 patients); 2) grafts to the nasal and/or sinus floor after a transoral exposure and elevation of the mucosa of the maxillary sinus and/or the nasal mucosa (33 implants in 11 patients); or 3) a combination of these two (5 implants in 2 patients). In totally edentulous patients, implants and grafts were used as a combination of grafting to both the alveolar ridge and nasal and/or sinus floor sites (61 implants in 9 patients). One hundred of 107 implants showed normal clinical and radiologic healing, whereas 7 implants in 4 patients (6.5%) were lost prior to loading. Seventeen patients have had the implants and bone grafts loaded by a prosthodontic reconstruction from 6 to 26 months (mean, 14 months) without loss of any implants. Postoperative marginal resorption of the onlay bone graft of less than 15% was observed. These findings suggest, that the previously observed rapid resorption of endochondral iliac crest onlay bone grafts and the number of lost implants can be significantly reduced if bone from the mandibular symphysis firmly anchored with titanium implants is used.

Influence of menopause on serum lipids and lipoproteins

The influence of the menopause on serum lipids and lipoproteins was examined longitudinally at 6-week intervals for 2-3 years in pre-menopausal women undergoing the menopause. Serum lipid and lipoprotein profiles were also examined cross-sectionally in 4 groups of pre-menopausal, peri-menopausal and post-menopausal women, who were followed up longitudinally at 3-monthly examinations for 1-2 years. The results covering 1360 examinations and 270 woman-years are reported here. Serum concentrations of total cholesterol (P = 0.001), low-density-lipoprotein (LDL) cholesterol (P = 0.001) and triglycerides (P less than 0.05) increased significantly as a consequence of the menopause and all increases occurred within 6 months of cessation of menstrual periods. High-density-lipoprotein (HDL) cholesterol decreased significantly (P less than 0.05) as a consequence of the menopause, but the decline occurred gradually over the 2 years preceding cessation of menses. In addition to the menopausal changes, serum concentrations of total cholesterol and LDL-cholesterol increased gradually in the pre-menopausal and post-menopausal years, but were significantly related to biological age only in the pre-menopausal groups (P less than 0.05). Serum triglycerides and HDL-cholesterol levels remained virtually unchanged in the pre-menopausal as well as the post-menopausal groups and were only influenced by the actual menopause. Serum lipids and lipoproteins are thus significantly altered as a consequence of the menopause. The result is a more atherogenic lipid profile which may partly explain the increased risk of cardiovascular disease observed in post-menopausal women.

Potentially predictive and manipulable blood serum correlates of aging in the healthy human male: progressive decreases in bioavailable testosterone, dehydroepiandrosterone sulfate, and the ratio of insulin-like growth factor 1 to growth hormone

A cross-sectional survey was made in 56 exceptionally healthy males, ranging in age from 20 to 84 years. Measurements were made of selected steroidal components and peptidic hormones in blood serum, and cognitive and physical tests were performed. Of those blood serum variables that gave highly significant negative correlations with age (r > -0.6), bioavailable testosterone (BT), dehydroepiandrosterone sulfate (DHEAS), and the ratio of insulin-like growth factor 1 (IGF-1) to growth hormone (GH) showed a stepwise pattern of age-related changes most closely resembling those of the age steps themselves. Of these, BT correlated best with significantly age-correlated cognitive and physical measures. Because DHEAS correlated well with BT and considerably less well than BT with the cognitive and physical measures, it seems likely that BT and/or substances to which BT gives rise in tissues play a more direct role in whatever processes are rate-limiting in the functions measured and that DHEAS relates more indirectly to these functions. The high correlation of IGF-1/GH with age, its relatively low correlation with BT, and the patterns of correlations of IGF-1/GH and BT with significantly age-correlated cognitive and physical measures suggest that the GH-IGF-1 axis and BT play independent roles in affecting these functions. Serial determinations made after oral ingestion of pregnenolone and data from the literature suggest there is interdependence of steroid metabolic systems with those operational in control of interrelations in the GH-IGF-1 axis. Longitudinal concurrent measurements of serum levels of BT, DHEAS, and IGF-1/GH together with detailed studies of their correlations with age-correlated functional measures may be useful in detecting early age-related dysregulations and may be helpful in devising ameliorative approaches.

The epidemiology of shoulder dislocations

In an urban population of a quarter of a million, all shoulder dislocations that occurred in a 5-year period were recorded. A total of 216 shoulder dislocations were seen, 53.3% in men. The overall incidence rate was 17/100,000 per year. Incidence peaks were found in the age-group 21-30 years among men and in the age-group 61-80 years among women. Significantly more patients in the older age groups, and especially women, dislocated at home by falling on an outstretched arm, whereas the younger age-groups most frequently dislocated outside the home, e.g., on sports fields. A considerable number of patients (18.6%) were hospitalized, and 85.5% of the patients required outpatient follow-up. Prophylactic measures should be taken especially to increase the safety of the elderly in their homes.

mRNA profiling of rat islet tumors reveals nkx 6.1 as a beta-cell-specific homeodomain transcription factor

Development of a high capacity multiplex reverse transcriptase-polymerase chain reaction protocol has allowed us to screen lineage related rat islet tumors classified as alpha-, beta-, and delta-like as judged by their hormone profile for differential expression of more than 50 selected genes. We find that in addition to insulin the insulinoma express the normal beta-cell markers Pdx-1, IAPP, and Glut-2, and that these markers are absent from the glucagonoma: a reflection of the normal alpha-cell. Furthermore, this study suggests that the GLP-1, glucagon, GIP, IGF-1, and insulin receptors as well as E-cadherin, R-cadherin, Id-1, and Id-2 are differentially expressed within the islet of Langerhans. Importantly, insulinoma-specific expression of the recently cloned homeodomain protein Nkx 6.1 predicted beta-cell-specific expression in the normal islet. Immunohistochemistry using antibodies raised against recombinant Nkx 6.1 did indeed localize Nkx 6.1 expression exclusively to the nuclei of normal islet beta-cells. Apart from pancreatic islets only the antral part of the stomach contained Nkx 6.1 mRNA. We conclude that multiplex reverse transcriptase-polymerase chain reaction-based mRNA profiling is a powerful tool to identify differentially expressed genes within phenotypically related cells and propose that Nkx 6.1 is involved in specifying the unique characteristics of the beta-cell.

Classification of trochanteric fractures

A comparative analysis of the information contained in five different classification systems was performed. The system classifying the fractures into five types in relation to the comminution of the calcar femorale or greater trochanter was found to be superior to the others, as it contained the most reliable information about the possibility of obtaining stable fracture reduction and gave the most accurate prediction of the risk of secondary fracture dislocation.

Glucocorticoid-induced insulin resistance in skeletal muscles: defects in insulin signalling and the effects of a selective glycogen synthase kinase-3 inhibitor

AIMS/HYPOTHESIS

Treatment with glucocorticoids, especially at high doses, induces insulin resistance. The aims of the present study were to identify the potential defects in insulin signalling that contribute to dexamethasone-induced insulin resistance in skeletal muscles, and to investigate whether the glycogen synthase-3 (GSK-3) inhibitor CHIR-637 could restore insulin-stimulated glucose metabolism.

MATERIALS AND METHODS

Skeletal muscles were made insulin-resistant by treating male Wistar rats with dexamethasone, a glucocorticoid analogue, for 12 days. Insulin-stimulated glucose uptake, glycogen synthesis and insulin signalling were studied in skeletal muscles in vitro.

RESULTS

Dexamethasone treatment decreased the ability of insulin to stimulate glucose uptake, glycogen synthesis and glycogen synthase fractional activity. In addition, the dephosphorylation of glycogen synthase by insulin was blocked. These defects were paralleled by reduced insulin-stimulated protein kinase B (PKB) and GSK-3 phosphorylation. While expression of PKB, GSK-3 and glycogen synthase was not reduced by dexamethasone treatment, expression of the p85alpha subunit of phosphatidylinositol 3-kinase (PI 3-kinase) was increased. Inhibition of GSK-3 by CHIR-637 increased glycogen synthase fractional activity in soleus muscle from normal and dexamethasone-treated rats, although the effect was more pronounced in control rats. CHIR-637 did not improve insulin-stimulated glucose uptake in muscles from dexamethasone-treated rats.

CONCLUSIONS/INTERPRETATION

We demonstrated that chronic dexamethasone treatment impairs insulin-stimulated PKB and GSK-3 phosphorylation, which may contribute to insulin resistance in skeletal muscles. Acute pharmacological inhibition of GSK-3 activated glycogen synthase in muscles from dexamethasone-treated rats, but GSK-3 inhibition did not restore insulin-stimulated glucose uptake.