Pancreatic and duodenal homeobox gene 1 induces expression of insulin genes in liver and ameliorates streptozotocin-induced hyperglycemia

Insulin gene expression is restricted to islet beta cells of the mammalian pancreas through specific control mechanisms mediated in part by specific transcription factors. The protein encoded by the pancreatic and duodenal homeobox gene 1 (PDX-1) is central in regulating pancreatic development and islet cell function. PDX-1 regulates insulin gene expression and is involved in islet cell-specific expression of various genes. Involvement of PDX-1 in islet-cell differentiation and function has been demonstrated mainly by 'loss-of-function' studies. We used a 'gain-of-function' approach to test whether PDX-1 could endow a non-islet tissue with pancreatic beta-cell characteristics in vivo. Recombinant-adenovirus-mediated gene transfer of PDX-1 to the livers of BALB/C and C57BL/6 mice activated expression of the endogenous, otherwise silent, genes for mouse insulin 1 and 2 and prohormone convertase 1/3 (PC 1/3). Expression of PDX-1 resulted in a substantial increase in hepatic immunoreactive insulin content and an increase of 300% in plasma immunoreactive insulin levels, compared with that in mice treated with control adenovirus. Hepatic immunoreactive insulin induced by PDX-1 was processed to mature mouse insulin 1 and 2 and was biologically active; it ameliorated hyperglycemia in diabetic mice treated with streptozotocin. These data indicate the capacity of PDX-1 to reprogram extrapancreatic tissue towards a beta-cell phenotype, may provide a valuable approach for generating 'self' surrogate beta cells, suitable for replacing impaired islet-cell function in diabetics.

Continued breast cancer risk reduction in postmenopausal women treated with raloxifene: 4-year results from the MORE trial. Multiple outcomes of raloxifene evaluation

Raloxifene, a selective estrogen receptor modulator approved for the prevention and treatment of postmenopausal osteoporosis, has shown a significant reduction in breast cancer incidence after 3 years in this placebo-controlled, randomized clinical trial in postmenopausal women with osteoporosis. This article includes results from an additional annual mammogram at 4 years and represents 3,004 additional patient-years of follow-up in this trial. Breast cancers were ascertained through annual screening mammograms and adjudicated by an independent oncology review board. A total of 7,705 women were enrolled in the 4-year trial; 2,576 received placebo, 2,557 raloxifene 60 mg/day, and 2,572 raloxifene 120 mg/day. Women were a mean of 66.5-years old at trial entry, 19 years postmenopause, and osteoporotic (low bone mineral density and/or prevalent vertebral fractures). As of 1 November 1999, 61 invasive breast cancers had been reported and were confirmed by the adjudication board, resulting in a 72% risk reduction with raloxifene (relative risk (RR) 0.28, 95% confidence interval (CI) 0.17, 0.46). These data indicate that 93 osteoporotic women would need to be treated with raloxifene for 4 years to prevent one case of invasive breast cancer. Raloxifene reduced the risk of estrogen receptor-positive invasive breast cancer by 84% (RR 0.16, 95% CI 0.09, 0.30). Raloxifene was generally safe and well-tolerated, however, thromboembolic disease occurred more frequently with raloxifene compared with placebo (p=0.003). We conclude that raloxifene continues to reduce the risk of breast cancer in women with osteoporosis after 4 years of treatment, through prevention of new cancers or suppression of subclinical tumors, or both. Additional randomized clinical trials continue to evaluate this effect in postmenopausal women with osteoporosis, at risk for cardiovascular disease, and at high risk for breast cancer.

A molecular basis for insulin resistance. Elevated serine/threonine phosphorylation of IRS-1 and IRS-2 inhibits their binding to the juxtamembrane region of the insulin receptor and impairs their ability to undergo insulin-induced tyrosine phosphorylation

Tumor necrosis factor alpha (TNFalpha) or chronic hyperinsulinemia that induce insulin resistance trigger increased Ser/Thr phosphorylation of the insulin receptor (IR) and of its major insulin receptor substrates, IRS-1 and IRS-2. To unravel the molecular basis for this uncoupling in insulin signaling, we undertook to study the interaction of Ser/Thr-phosphorylated IRS-1 and IRS-2 with the insulin receptor. We could demonstrate that, similar to IRS-1, IRS-2 also interacts with the juxtamembrane (JM) domain (amino acids 943-984) but not with the carboxyl-terminal region (amino acids 1245-1331) of IR expressed in bacteria as His6 fusion peptides. Moreover, incubation of rat hepatoma Fao cells with TNFalpha, bacterial sphingomyelinase, or other Ser(P)/Thr(P)-elevating agents reduced insulin-induced Tyr phosphorylation of IRS-1 and IRS-2, markedly elevated their Ser(P)/Thr(P) levels, and significantly reduced their ability to interact with the JM region of IR. Withdrawal of TNFalpha for periods as short as 30 min reversed its inhibitory effects on IR-IRS interactions. Similar inhibitory effects were obtained when Fao cells were subjected to prolonged (20-60 min) pretreatment with insulin. Incubation of the cell extracts with alkaline phosphatase reversed the inhibitory effects of insulin. These findings suggest that insulin resistance is associated with enhanced Ser/Thr phosphorylation of IRS-1 and IRS-2, which impairs their interaction with the JM region of IR. Such impaired interactions abolish the ability of IRS-1 and IRS-2 to undergo insulin-induced Tyr phosphorylation and further propagate the insulin receptor signal. Moreover, the reversibility of the TNFalpha effects and the ability to mimic its action by exogenously added sphingomyelinase argue against the involvement of a proteolytic cascade in mediating the acute inhibitory effects of TNFalpha on insulin action.

Tumor necrosis factor alpha-induced phosphorylation of insulin receptor substrate-1 (IRS-1). Possible mechanism for suppression of insulin-stimulated tyrosine phosphorylation of IRS-1

Tumor necrosis factor-alpha (TNF) has been suggested to be the mediator of insulin resistance in infection, tumor cachexia, and obesity. We have previously shown that TNF diminishes insulin-induced tyrosine phosphorylation of insulin receptor substrate 1 (IRS-1). The current work examines potential mechanisms that mediate this event. TNF effect on IRS-1 in Fao hepatoma cells was not associated with a significant reduction in insulin receptor tyrosine kinase activity as measured in vitro but impaired the association of IRS-1 with phosphatidylinositol 3-kinase, localizing TNF impact to IRS-1. TNF did not increase protein-tyrosine phosphatase activity and protein-tyrosine phosphatase inhibition by vanadate did not change TNF effect on IRS-1 tyrosine phosphorylation, suggesting that protein-tyrosine phosphatases are not involved in this TNF effect. In contrast, TNF increased IRS-1 phosphorylation on serine residues, leading to a decrease in its electrophoretic mobility. TNF effect on IRS-1 tyrosine phosphorylation was not abolished by inhibiting protein kinase C using staurosporine, while inactivation of Ser/Thr phosphatases by calyculin A and okadaic acid mimicked it. Our data suggest that TNF induces serine phosphorylation of IRS-1 through inhibition of serine phosphatases or activation of serine kinases other than protein kinase C. This increased serine phosphorylation interferes with insulin-induced tyrosine phosphorylation of IRS-1 and impairs insulin action.

Controlled trial of high spermatic vein ligation for varicocele in infertile men

OBJECTIVE

To determine whether high ligation is an effective treatment for infertile men with clinical varicocele.

DESIGN

A randomized, controlled trial of high spermatic vein ligation was carried out. The patients were treated and observed for 3 years.

SETTING

Infertility treatment clinic and andrology laboratory in a hospital.

PATIENTS

Infertile men with abnormal semen analysis because of varicocele only.

INTERVENTION

High ligation 1 year postrecruitment (group A) and at the beginning of the study (group B).

RESULTS

Among the 20 couples in group A, 2 pregnancies (10%) were achieved within the 1st year of observation period. During the year after high ligation, there were 8 pregnancies (44.4%), and during the 2nd year after high ligation, there were 4 more pregnancies (22.2%). In group B, 15 pregnancies (60%) occurred within the 1st year after operation. Three pregnancies (12%) and 1 pregnancy (4%) occurred during the 2nd and 3rd year, respectively. After operation in all patients of both groups, there was significant improvement in semen parameters, regardless of pregnancy occurrence. The difference in pregnancy rate (PR) between the operated group B and nonoperated group A during the 1st year of study was found to be highly significant.

CONCLUSIONS

It is concluded that in a population of infertile men presenting varicocele as the only demonstrable factor of infertility, the varicocele is clearly associated with infertility and reduced testicular function, and its correction by ligation improves sperm parameters and fertility rate. Furthermore, the highest PR in both groups occurred during the 1st year postoperation.

Elevated serum uric acid--a facet of hyperinsulinaemia

In a representative sample of the adult Jewish population in Israel (n = 1016) excluding known diabetic patients and individuals on antihypertensive medications, serum uric acid showed a positive association with plasma insulin response (sum of 1- and 2-hour post glucose load levels) in both males (r = 0.316, p less than 0.001) and females (r = 0.236, p less than 0.001). This association remained statistically significant in both sexes (p less than 0.001) after accounting by multiple regression analysis for age and major correlates of serum uric acid i.e. body mass index, glucose response (sum of 1- and 2-hour post load levels), systolic blood pressure and total plasma triglycerides. The net portion of the variance of serum uric acid attributable to insulin response was 12% in males and 8% in females, the total variance accountable by all these variables being 17% and 19% respectively. We conclude that elevated serum uric acid is a feature of hyperinsulinaemia/insulin resistance.

Sphingomyelinase and ceramide suppress insulin-induced tyrosine phosphorylation of the insulin receptor substrate-1

The sphingomyelin pathway is a newly described signal transduction pathway mediating the action of several cytokines including tumor necrosis factor-alpha (TNF). TNF was recently shown to interfere with insulin-induced tyrosine phosphorylation of the insulin receptor substrate-1 (IRS-1). In this work we examined the possible effect of direct activation of the sphingomyelin pathway on insulin-induced tyrosine phosphorylation of IRS-1. Incubation of the insulin-sensitive rat hepatoma Fao cells with bacterial sphingomyelinase (SMase) that causes membrane hydrolysis of sphingomyelin led to a time- and dose-dependent decrease in insulin-induced tyrosine phosphorylation of IRS-1. The effect was apparent after 10 min of incubation and with a dose of 10 milliunits/ml SMase. It was not associated with a decrease in insulin receptor autophosphorylation. In addition, SMase treatment interrupted the association of the 85-kDa catalytic subunit of phosphatidylinositol 3-kinase with IRS-1. A similar impact on IRS-1 tyrosine phosphorylation was observed after addition of cell-permeable ceramide analogs (C2 and C6). Comparable changes in IRS-1 tyrosine phosphorylation and electrophoretic mobility were found after exposure of cells to either TNF, SMase, or ceramide. Our findings suggest that TNF may utilize the sphingomyelin pathway in its effect on the insulin-stimulated tyrosine phosphorylation of IRS-1.

The STOP-NIDDM Trial: an international study on the efficacy of an alpha-glucosidase inhibitor to prevent type 2 diabetes in a population with impaired glucose tolerance: rationale, design, and preliminary screening data. Study to Prevent Non-Insulin-Dependent Diabetes Mellitus

OBJECTIVE

To describe the rationale and design, and to discuss the preliminary screening data, of the Study to Prevent NIDDM (STOP-NIDDM Trial), an international study on the efficacy of the alpha-glucosidase inhibitor acarbose in preventing or delaying the development of type 2 diabetes in a population with impaired glucose tolerance (IGT).

RESEARCH DESIGN AND METHODS

A total of 1,418 subjects diagnosed with IGT according to the World Health Organization's criteria and having a fasting plasma glucose concentration > or =5.6 mmol/L were randomized in a double-blind fashion to receive either acarbose (100 mg t.i.d.) or placebo for a predictive median follow-up period of 3.9 years. The primary outcome is the development of type 2 diabetes diagnosed using a 75-g oral glucose tolerance test according to the new criteria. The secondary outcomes are changes in blood pressure, lipid profile, insulin sensitivity, cardiovascular events, and morphometric profile.

RESULTS

Screening was performed in a high-risk population. As of 1 March 1997, 4,424 subjects had been screened, and data were available for 3,919 (88.5%) subjects. Of these subjects, 1,200 (30.6%) had glucose intolerance. Of the subjects with glucose intolerance, 521 (13.3%) had previously undetected type 2 diabetes, and 679 (17.3%) had IGT. Of the IGT population, 412 (60.7%) subjects were eligible for the study This population had the following characteristics: the mean age was 54.8 years, 52% of the subjects were female, 53% had more than one risk factor for type 2 diabetes, >90% had a family history of diabetes, 78.2% had a BMI > or =27 kg/m2, 47.5% had high blood pressure, 51.2% had dyslipidemia, and 22.8% of the women had a history of gestational diabetes.

CONCLUSIONS

Screening of a high-risk population yields one eligible subject per every 10 volunteers screened. This study should definitely answer the question of whether acarbose can prevent or delay the progression of IGT to type 2 diabetes mellitus.

Effect of past and concurrent body mass index on prevalence of glucose intolerance and type 2 (non-insulin-dependent) diabetes and on insulin response. The Israel study of glucose intolerance, obesity and hypertension

A representative sample (n = 2140) of the Israeli Jewish population aged 40-70 (excluding known diabetic patients), whose body mass index had been measured 10 years earlier, underwent an oral glucose tolerance test and redetermination of body mass index. Irrespective of weight changes, high concurrent and high past body mass index values (greater than or equal to 27) were associated with similarly increased rates of glucose intolerance as compared with body mass index values less than 27 at both time-points (rate ratio 1.76, 90% confidence limits 1.56-1.99). Glucose intolerance here includes borderline and impaired tolerance as well as Type 2 diabetes. The rate of Type 2 diabetes increased only with increasing past body mass index, while concurrent body mass index had no effect [rate ratios: 2.36 (1.48-3.75) and 1.99 (1.48-2.68) respectively for the medium-(23-26.9) versus-low (less than 23) and high- (greater than or equal to 27) versus-medium past body-mass-index categories]. Weight reduction was associated with only slightly reduced rate of glucose intolerance and had no effect on the rate of diabetes. Mean sum insulin (summed 1 and 2 h levels, mU/l) increased significantly with increasing concurrent body mass index (123, 150 and 190 in the low, medium and high categories) with no effect of past body mass index. It also increased significantly (p less than 0.001) in all concurrent body mass index categories from normal tolerance through borderline to impaired tolerance, and decreased significantly (p less than 0.001) in diabetes relative to impaired tolerance, although it remained above normal.(ABSTRACT TRUNCATED AT 250 WORDS)

Effectiveness of glycosylated hemoglobin, fasting plasma glucose, and a single post load plasma glucose level in population screening for glucose intolerance

Five shortcut methods of population screening for glucose intolerance (impaired glucose tolerance and non-insulin-dependent diabetes mellitus) were assessed for effectiveness: 1) glycosylated hemoglobin concentration (HbA1), 2) fasting plasma glucose level, 3) combinations of fasting plasma glucose and HbA1, 4) plasma glucose one hour post oral glucose load, and 5) plasma glucose two hour post oral glucose load. In a sample of the Israeli Jewish population aged 40-70 years, 2040 participants in the Israel Study of Glucose Intolerance, Obesity and Hypertension, who were not known to be diabetic, underwent an oral glucose tolerance test based on three blood samples (fasting, one hour, and two hour post oral glucose load). In 1058 of the subjects, HbA1 was also measured, and was found to increase significantly (P less than 0.001) with increasing glucose intolerance, but with extensive overlap of ranges, even between normals and newly found diabetics. Fasting plasma glucose was more effective than HbA1 in screening for both impaired glucose tolerance and diabetes by its higher specificity and predictive value of a positive test at comparable sensitivity levels. Combinations of HbA1 and fasting plasma glucose did not improve prediction over fasting plasma glucose alone. As observed in other studies, the screening effectiveness of fasting plasma glucose was also unsatisfactory, either post load glucose level being more effective. Plasma glucose level two hour post load was better for detection of diabetes alone. Plasma glucose level one hour post load was more effective at detecting the total group of glucose intolerance, but did not discriminate well between impaired tolerance and diabetes. A cost-risk-benefit evaluation suggests that a full three-sample oral glucose tolerance test is the best method in screening for both intolerance categories.

Genetically programmed selective islet beta-cell loss in diabetic subjects with Wolfram's syndrome

Insulin-producing beta-cells were selectively absent from the islets of Langerhans in postmortem specimens from two patients with Wolfram's syndrome. In families with multiple cases of this syndrome, we found a very high concordance rate (r = .910, P less than .001) among siblings for age at onset of diabetes mellitus. Taken together with the lack of markers for an autoimmune process, these findings suggest that diabetes mellitus in this syndrome results from genetically programmed selective beta-cell death.

Hyperinsulinemia induces a reversible impairment in insulin receptor function leading to diabetes in the sand rat model of non-insulin-dependent diabetes mellitus

The insulin receptor was evaluated at different disease stages in the sand rat (Psammomys obesus), a model for nutrition-induced diabetes. Nondiabetic sand rats showed markedly low receptor number in liver compared with albino rats. Their receptor had an intact tyrosine kinase activity but a higher Km for ATP in the phosphorylation reaction of exogenous substrates. The initial effects of overeating (i.e., development of hyperinsulinemia without hyperglycemia) were associated in the sand rat with a dramatic decrease in in vitro and in vivo insulin-induced receptor tyrosine kinase activity in both liver and muscle. In muscle, this coincided with a decrease in receptor number and an increase in basal tyrosine kinase activity. Similar changes were observed upon development of hyperinsulinemia with hyperglycemia. Upon recovery from the diabetic state by diet restriction, the impaired receptor kinase activation was corrected. Complete restoration occurred only in animals that fully recovered from the diabetic state and became normoinsulinemic. These observations indicate that loss and gain of receptor tyrosine kinase activity were dependent on insulin levels. Thus, overeating may lead to the development of hyperinsulinemia through ineffective extraction of excess insulin by the scarce liver receptors. Hyperinsulinemia, in turn, causes a reversible reduction in receptor kinase activity, leading to insulin resistance. This sequence of events may be relevant to diet-related changes in human non-insulin-dependent diabetes mellitus.

Synthesis of novel pyridyl containing phospholanes and their polynuclear luminescent copper(i) complexes

A novel type of cyclic P,N-ligands, pyridyl containing phospholanes, has been synthesized in a moderate yield by the reaction of primary phosphines with 1,4-dichlorobutane in a superbasic medium. A series of homo tetranuclear octahedral Cu4I4L2, dinuclear tetrahedral Cu2I2L3, and dinuclear "head-to-tail" Cu2I2L2 luminescent complexes with these ligands were obtained. All the compounds were characterized using a range of spectroscopic and computational techniques, and in the case of some Cu4I4L2 and Cu2I2L3 complexes, by single crystal X-ray diffraction. The structural diversity of the obtained complexes was reflected in their photophysical properties: phosphorescence spectra of the compounds display emission in broad spectral range of 471-615 nm. TD-DFT computations allow the assignment of a single emission band around 550 nm for Cu2I2L3 complexes and 471 nm for Cu2I2L2 complex to a vertical triplet-singlet transition from a metal-to-ligand and halide-to-ligand charge-transfer (3)(M + X)LCT excited state, whereas a second band at around 600 nm in the spectra of octahedral Cu4I4L2 complexes was assigned predominantly to Cu4I4 cluster-centered ((3)CC) excited state.

Acarbose for the prevention of Type 2 diabetes, hypertension and cardiovascular disease in subjects with impaired glucose tolerance: facts and interpretations concerning the critical analysis of the STOP-NIDDM Trial data

The STOP-NIDDM Trial has shown that acarbose treatment in subjects with impaired glucose tolerance is associated with a significant risk reduction in the development of diabetes, hypertension and cardiovascular complications. Kaiser and Sawicki have accused the investigators of the STOP-NIDDM Trial of major biases in the conduct of the study, of manipulating the data and of conflict of interest. The aim of this paper is to present data and explanations refuting these allegations. In the STOP-NIDDM Trial, 61 subjects were excluded from the efficacy analysis before unblinding for legitimate reasons: failure to satisfy major entry criteria (n=17) and lack of post-randomisation data (n=44). Blinding and randomisation were carried out by an independent biostatistician. Titration of placebo/acarbose is well described in the protocol and in the study design paper. Of the study population, 9.3% had a fasting plasma glucose of > or =7.0 mmol/l at screening and could have been diabetic according to the new diagnostic criteria. However, even if these subjects are excluded, patients having acarbose treatment still saw a significant risk reduction in the development of diabetes (p=0.0027). The changes in weight are consistent in different publications and are related to different times of follow-up and assessment. Weight change does have an effect on the development of diabetes, but acarbose treatment is still effective even after adjusting for this (p=0.0063). The cardiovascular endpoints were a clearly designated assessment in the original protocol, and only those defined in the protocol and ascertained by the independent Cardiovascular Event Adjudication Committee were used in the analysis. Hypertension was defined according to the most recent diagnostic criteria. The STOP-NIDDM Trial results are scientifically sound and credible. The investigators stand strongly behind these results demonstrating that acarbose treatment is associated with a delay in the development of diabetes, hypertension and cardiovascular complications in a high-risk population with IGT.

Hyperinsulinemia, sex, and risk of atherosclerotic cardiovascular disease

BACKGROUND

The possibility that hyperinsulinemia may be involved in the etiology of atherosclerotic cardiovascular disease (CVD) was first suggested 20 years ago. During the last decade, this possibility has received support from three large prospective studies.

METHODS AND RESULTS

In the present study, the association between CVD, glucose intolerance, obesity, and hypertension (the GOH conditions) and hyperinsulinemia was examined cross-sectionally in a representative sample (n = 1,263) of the adult Jewish population aged 40-70 years in Israel. Previously known diabetics were excluded. CVD comprising clinical or ECG evidence of ischemic heart disease, as well as clinical evidence of cerebrovascular or peripheral vascular disease, was identified in 97 men and 39 women. A significant (p less than 0.01) hyperinsulinemia-sex interaction was found for CVD rate, with the adjusted risk ratios (followed by 95% confidence limits), relative to the rate in 298 normoinsulinemic women, being 1.15 (0.68-1.95) in 328 normoinsulinemic men, 0.85 (0.48-1.49) in 277 hyperinsulinemic women, and 2.27 (1.33-3.08) in 360 hyperinsulinemic men. Age-adjusted CVD rates in men versus women were: a) similar and low among all normoinsulinemic normotensives and hyperinsulinemics free of any of the GOH conditions (all rates less than or equal to 6.5%); b) similar and high among normoinsulinemic hypertensives (13.4% versus 10.4%); c) significantly higher in men among hyperinsulinemic normotensives with glucose intolerance and/or obesity (15.2% versus 3.3%; p = 0.02) and all hyperinsulinemic hypertensives (21.5% versus 12.8%; p = 0.04). These trends remained significant after adjusting for age, ethnic group, and blood lipids.

CONCLUSIONS

Therefore, hyperinsulinemia was associated with excess CVD risk in men but not in women, and all excess CVD risk in men was confined to hyperinsulinemic individuals in the presence of glucose intolerance, obesity, or hypertension.

Long-term treatment of Laron type dwarfs with insulin-like growth factor-1 increases serum insulin-like growth factor-binding protein-3 in the absence of growth hormone activity

Insulin-like growth factor binding protein-3 (IGFBP-3) is the major carrier of insulin-like growth factor I (IGF-I) in serum, and its production is growth hormone (GH) dependent. It is unclear whether in humans IGFBP-3 production is directly regulated by GH or mediated via IGF-I. We addressed this question in six patients with Laron-type dwarfism, a syndrome characterized by the absence of GH receptor activity (LTD), who were chronically treated with recombinant IGF-I. Analysis of the electrophoretic profiles of serum IGFBPs in these patients by Western ligand blotting revealed an extremely low IGFBP-3 level. A striking progressive increase in serum IGFBP-3 was observed with continuous treatment, despite the absence of GH action. In LTD children, serum IGFBP-3 increased up to 19-fold after six months of therapy and equalled levels observed in controls, whereas in adult LTD patients the increase was smaller. A rise in serum levels of 34, 30 and 24 kDa BPs (presumably IGFBP-2, -1 and -4, respectively was also noted with chronic IGF-I therapy. This proof of GH-independent induction of IGFBP-3 by IGF-I may be a major advantage in the therapeutic use of biosynthetic IGF-I in several types of short stature children.

Serum insulin-like growth factor-binding protein-2 (IGFBP-2) is increased and IGFBP-3 is decreased in patients with prostate cancer: correlation with serum prostate-specific antigen

Insulin-like growth factors (IGFs) are potent mitogens that stimulate the growth of prostate cells. In serum, IGFs circulate bound to IGF-binding proteins (IGFBPs), which modulate their proliferative action. We studied the electrophoretic pattern of IGFBPs in the serum of patients with prostate cancer and in individuals with increased serum levels of prostate-specific antigen (PSA) in the absence of prostate malignancy. Serum IGFBP-2 was dramatically increased in patients with metastatic prostate cancer compared with healthy controls (23.83 +/- 6.93% vs. 2.95 +/- 0.52% of total serum IGFBPs; P < 0.02). A moderate rise in IGFBP-2 was also observed among patients with increased PSA without malignancy. In contrast, a decrease in serum IGFBP-3 was detected in most patients with metastatic prostate cancer (68.2 +/- 9.1% vs. 95.4 +/- 0.9% of total serum IGFBPs; P < 0.02) and was more pronounced in advanced cases. A highly significant correlation between serum IGFBP-2 and PSA levels was found (r = 0.62; P < 0.002), with a significant negative correlation between serum PSA and IGFBP-3 (r = -0.63; P < 0.002). We suggest that IGFBPs may be involved in growth modulation of prostate malignancy and that alterations in their serum levels may serve as a marker for prostate cancer.

The prognostic importance of the number of oocytes retrieved and estradiol levels in poor and normal responders in in vitro fertilization (IVF) treatment

A low response to ovarian stimulation in in vitro fertilization poses a unique therapeutic challenge. Gonadotropin-releasing hormone agonists (GnRHa) have been suggested as a modality for treatment of this condition. In this study, we analyzed the results of 880 in vitro fertilization treatment cycles with respect to modality of ovarian stimulation, degree of hormonal response, and number of oocytes retrieved. In patients with estradiol (E2) levels less than 501 pg/ml on the day of human chorionic gonadotropin administration, 27% pregnancy rate was achieved with clomiphene citrate (CC) combined with human menopausal gonadotropin (hMG), compared to 15.1% (P less than 0.005) with hMG alone and 20.8% (NS) with GnRHa and hMG. Pregnancy rates were not lower in these patients compared to patients with higher estradiol levels in the different stimulation protocols, but pregnancy rates were significantly lower in cycles during which three or fewer oocytes were retrieved, compared to those in which four or more oocytes were retrieved (10.8 vs 23.8%; P less than 0.0005). In low-retrieval cycles pregnancy rates actually decreased with increasing levels of estradiol. Our results indicate that the number of oocytes retrieved is a better prognostic parameter than E2 levels in predicting the outcome of in vitro fertilization treatment and that GnRHa in the long protocol do not seem to be superior to CC combined with hMG for the treatment of poor responders.

Familial prolactinoma

BACKGROUND

Apart from the rare association with type I multiple endocrine neoplasia (MEN-1), familial types of prolactinoma have not been reported.

PATIENTS AND MEASUREMENTS

Eight hyperprolactinaemic patients in four families and 18 of their first and second-degree relatives (parents, children and grandchildren) were examined. Hormone levels were measured, as well as other biochemical parameters.

RESULTS

Prolactinoma was diagnosed in more than one member of each of the four families.

CONCLUSION

Familial prolactinoma is a distinct entity which is probably due to a genetic mutation promoting lactotroph proliferation.

Increased insulin-like growth factor binding protein-2 (IGFBP-2) gene expression and protein production lead to high IGFBP-2 content in malignant ovarian cyst fluid

Expression of insulin-like growth factor-I (IGF-I), its receptor and IGF-binding proteins (IGFBPs) by ovarian cancer cells and its mitogenic effect on these cells in vitro, suggest that IGF-I may have a role in regulation of human ovarian cancer. We have recently shown IGFBP-2 to be markedly elevated in malignant ovarian cyst fluid in vivo. To identify the origin of increased IGFBP-2 in these cyst fluids, the gene expression and protein content of IGFBP-2 were investigated in 14 malignant and four benign epithelial ovarian neoplasms. IGFBP-2 mRNA was detected in all ovarian specimens and was 2- to 30-fold higher in malignant than in benign neoplasms. Within the malignant tissues IGFBP-2 mRNA levels correlated with the aggressiveness of the tumour and were higher in invasive tumours than in those with borderline pathology. Southern blot analysis revealed no amplification of IGFBP-2 gene in the DNA samples from ovarian tumours regardless of their nature. IGFBP-2 was the major binding protein in tissue extracts, as measured by both Western ligand blotting and immunoblotting, and was significantly higher in malignant than in benign neoplasms. These findings were further supported by immunohistochemical detection of IGFBP-2 in tumour sections. Our data suggest that increased local production by the tumour in vivo is responsible for the increased IGFBP-2 levels in the cyst fluid bathing the ovarian malignancy. This may represent an autocrine regulatory mechanism for IGF-I proliferative effect of ovarian cancer.