An exploratory double-blind, randomized clinical trial with selisistat, a SirT1 inhibitor, in patients with Huntington's disease

AIMS

Selisistat, a selective SirT1 inhibitor is being developed as a potentially disease-modifying therapeutic for Huntington's disease (HD). This was the first study of selisistat in HD patients and was primarily aimed at development of pharmacodynamic biomarkers.

METHODS

This was a randomized, double-blind, placebo-controlled, multicentre exploratory study. Fifty-five male and female patients in early stage HD were randomized to receive 10 mg or 100 mg of selisistat or placebo once daily for 14 days. Blood sampling, clinical and safety assessments were conducted throughout the study. Candidate pharmacodynamic markers included circulating soluble huntingtin and innate immune markers.

RESULTS

Selisistat was found to be safe and well tolerated, and systemic exposure parameters showed that the average steady-state plasma concentration achieved at the 10 mg dose level (125 nm) was comparable with the IC50 for SirT1 inhibition. No adverse effects on motor, cognitive or functional readouts were recorded. While circulating levels of soluble huntingtin were not affected by selisistat in this study, the biological samples collected have allowed development of assay technology for use in future studies. No effects on innate immune markers were seen.

CONCLUSIONS

Selisistat was found to be safe and well tolerated in early stage HD patients at plasma concentrations within the anticipated therapeutic concentration range.

HbA1c levels and all-cause mortality in type 2 diabetic patients: epidemiological evidence of the need for personalised therapeutic targets

BACKGROUND AND AIM

The aim of the present case-control study is to explore the effect of case mix on the relationship between glycated haemoglobin (HbA1c) and mortality in type 2 diabetic patients.

METHODS AND RESULTS

A nested case-control study data set was generated from the cohort-study data set (n = 4140 type 2 diabetic outpatients) by sampling controls from the risk sets. Cases (n = 427) were compared with an equal number of controls chosen from those members of the cohort who were at risk for the same follow-up time of the case, matched for age (±3 years), sex, body mass index (BMI) (±2 kg m(-2)), duration of diabetes (±5 years), and Charlson's Comorbidity Score (CCS) (±1). The main predefined analysis was the comparison of cases and controls for proportion of patients with each HbA1c class (<6.5%, 6.5-7.4%, 7.5-8.4% and ≥8.5%). During a mean follow-up of 5.7 ± 3.5 years, 427 deaths were recorded. The lowest risk of death was observed in the HbA1c 6.5-7.4% category; a lower HbA1c was associated with a non-significant trend towards a higher risk. The risk associated with a low (<6.5%) HbA1c was significantly greater in patients who were insulin-treated than in the rest of the sample.

CONCLUSIONS

The present study suggests that glycaemic targets should be individualised on the basis of the characteristics of each patient, considering age, co-morbidity and duration of diabetes. Caution should be used in prescribing insulin to reach near-normoglycaemia, particularly in older, frail patients.

Effects of antihypertensive treatments on incidence of diabetes: a case-control study

AIMS

Aim of this case-control study is the assessment of the relationship between antihypertensive treatment and incidence of diabetes in an unselected cohort of subjects participating in a screening program for diabetes.

METHODS

A case-control study nested within a cohort of nondiabetic subjects with a mean follow-up of 27.7 ± 11.3 months was performed, comparing 40 cases of incident diabetes and 160 controls matched for age, sex, body mass index, fasting plasma glucose, 2-h post-load glycemia, smoking and alcohol abuse.

RESULTS

When considering antihypertensive treatment at enrolment, a lower proportion of cases was exposed to ACE-inhibitors/angiotensin receptor blockers (ACE-i/ARB) in comparison with controls. A non-significant trend toward a higher exposure to diuretics, which were mainly represented by thiazide diuretics, was observed in cases. In a multivariate analysis, including both ACE-i/ARB and diuretics, a protective effect of ACEi/ARB, and an increased risk with diuretics were observed. Similar results were obtained in alternative models, after adjusting for systolic and diastolic blood pressure at enrolment, diagnosis of hypertension, concurrent treatment with β-blockers or calcium-channel blockers, and number of antihypertensive medications.

CONCLUSIONS

Diuretics seem to be associated with a higher incidence of diabetes, whereas treatment with ACEi/ARB could have a protective effect.

Effect of metformin on cardiovascular events and mortality: a meta-analysis of randomized clinical trials

AIM

Some studies suggested that metformin could reduce cardiovascular risk to a greater extent than that determined by glucose reduction. Aim of the present meta-analysis is to assess the effects of metformin on the incidence of cardiovascular events and mortality.

METHODS

An extensive search of Medline, EMBASE and the Cochrane Library (any date up to 31 October 2009) was performed for all trials containing the word 'metformin'. Randomized trials with a duration ≥52 weeks were included. A meta-regression analysis was also performed to identify factors associated with cardiovascular morbidity and mortality in metformin-treated patients.

RESULTS

A total of 35 clinical trials were selected including 7171 and 11 301 participants treated with metformin and comparator, respectively, who had 451 and 775 cardiovascular (CV) events, respectively. Overall, metformin was not associated with significant harm or benefit on cardiovascular events (MH-OR 0.94[0.82-1.07], p = 0.34). A significant benefit was observed in trials versus placebo/no therapy (MH-OR 0.79[0.64-0.98], p = 0.031), but not in active-comparator trials (MH-OR 1.03[0.72-1.77], p = 0.89). Meta-regression showed a significant correlation of the effect of metformin on cardiovascular events with trial duration and with minimum and maximum age for inclusion, meaning that the drug appeared to be more beneficial in longer trials enrolling younger patients. It is likely that metformin monotherapy is associated with improved survival (MH-OR: 0.801[0.625-1.024], p = 0.076). However, concomitant use with sulphonylureas was associated with reduced survival (MH-OR: 1.432[1.068-1.918], p = 0.016).

CONCLUSION

Available evidence seems to exclude any overall harmful effect of metformin on cardiovascular risk, suggesting a possible benefit versus placebo/no treatment. The observed detrimental effect of the combination with sulphonylureas deserves further investigation.

Key role of staff competencies for patient and donor safety in a bone marrow transplantation unit: design and implementation of an accredited training and self-assessment program

Human resources represent at the moment the most critical factor in an hospital setting characterized by a high rate of staff turnover. It is important to ensure a consistent level of expertise and knowledge of professionals who work in health care facilities to provide quality services and simultaneously support the implementation of strategies for patient safety. Unfortunately, the development of effective interventions for training newly added staff and self-evaluation of skills possessed by trained staff are closely related to understanding critical aspects of the organization. At the new Center for Bone Marrow Transplantation and Blood Transfusion Service in Meyer Hospital, during the last year, a group of professional nurses and technicians completed a specific plan to train new staff and, at the same time, a program of self-assessment of skills for experienced staff. The main purpose of this project was to promote skills development by newly added as well as experienced staff, to identify areas of weaknesses, and to correct them with training (organized by the hospital, departmental, or individual) designed to improve performance.

Dependence of time to death on molecular size of botulinum toxin

The molecular size of type A botulinum toxin affects the response in a time-to-death assay. Definitive statements of specific activity should be based on quantal assay.

Glucagon-like peptide-1 response to meals and post-prandial hyperglycemia in Type 2 diabetic patients

BACKGROUND

The impaired response of glucagonlike peptide-1 (GLP-1) to meals in diabetic patients can contribute to the pathogenesis of impaired insulin secretion and post-prandial hyperglycemia. This study is aimed at the assessment of the relationship between meal-induced GLP-1 and post-prandial hyperglycemia in Type 2 diabetic patients.

METHODS

Twenty-one drug-naïve Type 2 diabetic patients were studied. Blood glucose and active GLP-1 levels were measured 0, 30, 60, 90, and 120 min after a standard test meal. A continuous glucose monitoring (CGM) system was applied for the following 3 days. Nutrient intake at each meal was calculated on the basis of patients' food records. For each patient, post-prandial 120-min glucose incremental area under the curve (iAUC) was included in linear regression model exploring its relationship with total energy and carbohydrate intake, and the angular coefficient for total energy (EAC) and carbohydrate (CAC) was calculated.

RESULTS

GLP-1 levels peaked 30 min after the test meal. Logarithmically transformed 60-min GLP-1 iAUC showed a significant inverse correlation with glycated hemoglobin (HbA1c) (p<0.01). A significant inverse correlation of 60-min GLP-1 iAUC was also observed with EAC and CAC (both p<0.01), meaning that patients with a lower GLP-1 response to the test meal had a higher increment of post-prandial glucose for each additional unit of total energy or carbohydrate intake.

CONCLUSIONS

In Type 2 diabetic patients, a lower GLP-1 response to meals is associated with a higher HbA1c, and with a greater degree of meal-induced hyperglycemia, both in a meal test and during CGM in "real-life" conditions.

Prevention of cardiovascular disease through glycemic control in type 2 diabetes: a meta-analysis of randomized clinical trials

BACKGROUND AND AIMS

Randomized clinical trials (RCTs) aimed at the assessment of the efficacy of lowering blood glucose in the prevention of diabetic complications have always failed to detect a significant effect on cardiovascular events. Aim of this meta-analysis is the assessment of the effects of improvement of glycemic control on the incidence of cardiovascular diseases in patients with type 2 diabetes.

METHODS

The RCTs were included in this meta-analysis if: a) the between-group difference in mean HbA1c during the trial was at least 0.5%, b) they had a planned duration of treatment of at least 3 years, c) if they had a cardiovascular endpoint. Data for analysis were extracted independently by two observers and potential contrasts were resolved by a senior investigator.

RESULTS

Five studies (17,267 and 15,362 patients in the intensive and conventional therapy groups, respectively) were included. Intensive treatment, which reduced mean HbA1c by 0.9% on average, was associated with a significant reduction of incident cardiovascular events and myocardial infarction (OR 0.89 [0.83-0.95] and 0.86 [0.78-0.93], respectively), but not of stroke or cardiovascular mortality (OR 0.93 [0.81-1.07] and 0.98 [0.77-1.23], respectively). In meta-regression analysis, a higher BMI duration of diabetes, and incidence of severe hypoglycaemia were associated with greater risk for cardiovascular death in intensive treatment groups.

CONCLUSION

Intensified hypoglycaemic treatment in type 2 diabetic patients leads to a significant reduction of the incidence of myocardial infarction, while it does not affect the incidence of stroke and cardiovascular mortality. Hypoglycemia induced by intensified treatment could be associated with increased cardiovascular mortality.

KIF11 inhibition for glioblastoma treatment: reason to hope or a struggle with the brain?

Background

Glioblastomas (GBM) are typically comprised of morphologically diverse cells. Despite current advances in therapy, including surgical resection followed by radiation and chemotherapy, the prognosis for patients with GBM remains poor. Unfortunately, most patients die within 2 years of diagnosis of their disease. Molecular abnormalities vary among individual patients and also within each tumor. Indeed, one of the distinguishing features of GBM is its marked genetic heterogeneity. Due to the brain location of the tumor, the potential target inhibition for anticancer therapy must exhibit a manageable neurotoxicity profile in the concentration range in which the compounds show anti-proliferative activity.

Kinesin KIF11 inhibition by small molecules such as Monastrol or Ispinesib is currently under investigation in the field of malignant tumors. In the current study we have assessed the relevance of the anti-mitotic Kinesin-like protein KIF11 in human GBM cell-lines.

Results

In this study the target was validated using a set of well characterised and potentially specific small molecule inhibitors of KIF11: an ispinesib analog, Monastrol, a Merck compound and 3 simplified derivatives of the Merck compound. Following an in silico selection, those compounds predicted to bear a favorable BBB permeation profile were assessed for their phenotypic effect on cell lines derived both from primary (U87MG) as well as treated (DBTRG-05-MG) glioblastomas. For some compounds, these data could be compared to their effect on normal human astrocytes, as well as their neurotoxicity on primary rat cortical neurons. The ispinesib analogue 1 showed an anti-proliferative effect on GBM cell lines by blocking them in the G2/M phase in a concentration range which was shown to be harmless to primary rat cortical neurons. Furthermore, ispinesib analog increased caspase 3/7-induced apoptosis in U87MG cells.

Conclusion

In the area of cell cycle inhibition, KIF11 is critical for proper spindle assembly and represents an attractive anticancer target. Our results suggest that KIF11 inhibitors, when able to permeate the blood-brain-barrier, could represent an interesting class of anticancer drugs with low neurotoxic effects in the treatment of brain tumors.

Pioglitazone and cardiovascular risk. A comprehensive meta-analysis of randomized clinical trials

AIM

The aim of this meta-analysis of randomized clinical trials (RCT) was to assess whether pioglitazone is also associated with increased cardiovascular risk, as recently reported for rosiglitazone.

METHODS

RCT of pioglitazone were retrieved from Medline (any date up to 31 August 2007; English language only). Unpublished RCT were identified through http://www.clinicaltrials.gov or http://www.fda.gov websites, and results on cardiovascular outcomes were retrieved from investigators and/or sponsors, whenever possible. RCT were included in meta-analysis if pioglitazone was compared with other treatments (placebo, active comparators or no treatment) for at least 4 weeks. Ninety-four trials, 10 of which were unpublished, were retrieved; those included in the analysis, which excluded PROspective PioglitAzone Clinical Trial In MacroVascular Events (PROACTIVE), enrolled 11 268 and 9912 patients in the pioglitazone and comparator groups respectively. Data for analysis, extracted independently by two observers, included all-cause and cardiovascular mortality and incidence of non-fatal coronary events and heart failure. Proportions of outcome measures across treatment groups were compared by odds ratios (ORs) and 95% confidence interval.

RESULTS

Pioglitazone was associated with reduced all-cause mortality [OR 0.30 (0.14-0.63); p < 0.05], with no relevant effect on non-fatal coronary events. The observed increase in incidence of non-fatal heart failure was not statistically significant [OR 1.38 (0.90-2.12)].

CONCLUSION

The use of pioglitazone does not appear to be harmful in terms of cardiovascular events and all-cause deaths.

Opposing effects of D-aspartic acid and nitric oxide on tuning of testosterone production in mallard testis during the reproductive cycle

D-Aspartic acid (D-Asp) and nitric oxide (NO) play an important role in tuning testosterone production in the gonads of male vertebrates. In particular, D-Asp promotes either the synthesis or the release of testosterone, whereas NO inhibits it. In this study, we have investigated for the first time in birds the putative effects of D-Asp and NO on testicular testosterone production in relation to two phases of the reproductive cycle of the adult captive wild-strain mallard (Anas platyrhynchos) drake. It is a typical seasonal breeder and its cycle consists of a short reproductive period (RP) in the spring (April-May) and a non reproductive period (NRP) in the summer (July), a time when the gonads are quiescent. The presence and the localization of D-Asp and NO in the testis and the trends of D-Asp, NO and testosterone levels were assessed during the main phases of the bird's reproductive cycle. Furthermore, in vitro experiments revealed the direct effect of exogenously administered D-Asp and NO on testosterone steroidogenesis.

METHODS

By using immunohistochemical (IHC) techniques, we studied the presence and the distributional pattern of D-Asp and NO in the testes of RP and NRP drakes. D-Asp levels were evaluated by an enzymatic method, whereas NO content, via nitrite, was assessed using biochemical measurements. Finally, immunoenzymatic techniques determined testicular testosterone levels.

RESULTS

IHC analyses revealed the presence of D-Asp and NO in Leydig cells. The distributional pattern of both molecules was in some way correlated to the steroidogenic pathway, which is involved in autocrine testosterone production. Indeed, whereas NO was present only during the NRP, D-Asp was almost exclusively present during the RP. Consistently, the high testosterone testicular content occurring during RP was coupled to a high D-Asp level and a low NO content in the gonad. By contrast, in sexually inactive drakes (NRP), the low testosterone content in the gonad was coupled to a low D-Asp content and to a relatively high NO level. Consequently, to determine the exogenous effects of the two amino acids on testosterone synthesis, we carried out in vitro experiments using testis sections deriving from both the RP and NRP. When testis slices were incubated for 60 or 120 min with D-Asp, testosterone was enhanced, whereas in the presence of L-Arg, a precursor of NO, it was inhibited.

CONCLUSION

Our results provide new insights into the involvement of D-Asp and NO in testicular testosterone production in the adult captive wild-strain mallard drake. The localization of these two molecules in the Leydig cells in different periods of the reproductive cycle demonstrates that they play a potential role in regulating local testosterone production.

Treatment with insulin secretagogues and cancer-related mortality in type 2 diabetic patients a retrospective cohort study

BACKGROUND

Recent evidence suggests that some hypoglycemic treatments could affect the incidence of malignancies. This study was aimed at the assessment of cancer-related mortality in type 2 diabetic patients treated with different hypoglycemic drugs.

METHODS

A retrospective observational cohort study was performed on a consecutive series of 3002 type 2 diabetic outpatients. Cancer-related death was identified through the City Registry Office. For patients visited for the first time after January 1 (st), 2000, information on incidence of cancer was also available.

RESULTS

During a mean follow-up of 4.3+/-2.5 years, 87 cases of cancer-related death were recorded, with a yearly incidence rate of 0.70%. Patients receiving secretagogues showed a significantly higher mortality than the rest of the sample (unadjusted OR [95%CI] 1.76 [1.15-2.69], p=0.009), which was maintained after adjustment for confounders (HR 2.29 [1.21-4.02], p=0.003). Conversely, no significant association of cancer-related mortality was observed with insulin sensitizers or exogenous insulin. In comparison with patients receiving no hypoglycemic treatment, those on secretagogue or insulin monotherapy showed a higher cancer-related mortality (HR 2.25 [1.10-4.78], p=0.034 and HR 2.11 [1.01-4.50], p=0.048, respectively). The effect of treatments on incidence of malignancies was similar to that observed on cancer-related death.

CONCLUSIONS

Insulin secretagogues and, to a lesser extent, exogenous insulin, appear to be associated with increased mortality for cancer, even after adjustment for multiple confounders. This issue deserves further investigation through epidemiological studies on larger samples of patients.

AT1 Receptor Ligands: Virtual-Screening-Based Design with TOPP Descriptors, Synthesis, and Biological Evaluation of Pyrrolidine Derivatives

As a continuing effort to establish the structure-activity relationships (SARs) within the series of the angiotensin II antagonists (sartans), a pharmacophoric model was built by using novel TOPP 3D descriptors. Statistical values were satisfactory (PC4: r(2)=0.96, q(2) ((5) (random) (groups))=0.84; SDEP=0.26) and encouraged the synthesis and consequent biological evaluation of a series of new pyrrolidine derivatives. SAR together with a combined 3D quantitative SAR and high-throughput virtual screening showed that the newly synthesized 1-acyl-N-(biphenyl-4-ylmethyl)pyrrolidine-2-carboxamides may represent an interesting starting point for the design of new antihypertensive agents. In particular, biological tests performed on CHO-hAT(1) cells stably expressing the human AT(1) receptor showed that the length of the acyl chain is crucial for the receptor interaction and that the valeric chain is the optimal one.

Are sulphonylureas all the same? A cohort study on cardiovascular and cancer-related mortality

BACKGROUND

Aim of the present study is the comparison of all-cause, cardiovascular and non-cardiovascular mortality, and cardiac morbidity, between patients treated with glibenclamide and gliclazide.

METHODS

A retrospective observational cohort study was performed on a consecutive series of 568 outpatients (282 women, 286 men) with type 2 diabetes treated with either glibenclamide (n = 378) or gliclazide (n = 190). Information on all-cause mortality and on causes of death up to 31 December 2004 was obtained by the City of Florence Registry Office. Non-fatal cases requiring hospitalization were identified through the regional hospital discharge system using International Classification of Diseases.

RESULTS

Mean follow-up was 5.0 +/- 1.6 and 4.4 +/- 2.0 years for death and cardiac events, respectively; during follow-up, 33 and 11 deaths were observed in the glibenclamide and gliclazide groups, with a yearly mortality rate of 4.3 and 2.2%, respectively (p < 0.05). At Cox regression, after adjustment for potential confounders, including comorbidity, glibenclamide treatment was associated with a significant increase in all-cause mortality [OR 2.1(1.2;2.7), p < 0.05], while the difference in cardiovascular mortality was not statistically significant after adjustment for age and sex. Mortality for malignancies was significantly higher in patients treated with glibenclamide after adjustment for age, sex, BMI, and insulin and metformin treatment, [OR 3.6(1.1;11.9); p < 0.05]. A higher incidence of cardiac events was associated with glibenclamide treatment only in patients with previously known ischaemic heart disease.

CONCLUSIONS

Treatment with glibenclamide could be associated with higher mortality for cardiovascular diseases and malignancies, in comparison with gliclazide.

d-Aspartic acid and nitric oxide as regulators of androgen production in boar testis

D-Aspartic acid (D-Asp) and nitric oxide (NO) are two biologically active molecules playing important functions as neurotransmitters and neuromodulators of nerve impulse and as regulators of hormone production by endocrine organs. We studied the occurrence of D-Asp and NO as well as their effects on testosterone synthesis in the testis of boar. This model was chosen for our investigations because it contains more Leydig cells than other mammals. Indirect immunofluorescence applied to cryostat sections was used to evaluate the co-localization of D-Asp and of the enzyme nitric oxide synthase (NOS) in the same Leydig cells. D-Asp and NOS often co-existed in the same Leydig cells and were found, separately, in many other testicular cytotypes. D-Asp level was dosed by an enzymatic method performed on boar testis extracts and was 40+/-3.6 nmol/g of fresh tissue. NO measurement was carried out using a biochemical method by NOS activity determination and expressed as quantity of nitrites produced: it was 155.25+/-21.9 nmol/mg of tissue. The effects of the two molecules on steroid hormone production were evaluated by incubating testis homogenates, respectively with or without D-Asp and/or the NO-donor L-arginine (L-Arg). After incubation, the testosterone presence was measured by immunoenzymatic assay (EIA). These in vitro experiments showed that the addition of D-Asp to incubated testicular homogenates significantly increased testosterone concentration, whereas the addition of L-Arg decreased the hormone production. Moreover, the inclusion of L-Arg to an incubation medium of testicular homogenates with added D-Asp, completely inhibited the stimulating effects of this enantiomer. Our results suggest an autocrine action of both D-Asp and NO on the steroidogenetic activity of the Leydig cell.

Fasting and post-prandial glycemia and their correlation with glycated hemoglobin in Type 2 diabetes

OBJECTIVE

The relative contribution of fasting and post-prandial glucose to glycated hemoglobin (HbA1c) is controversial. In the present study, we assessed the relationship with HbA1c of fasting and post-prandial glucose measured in a more naturalistic setting, through home glucose self-monitoring or with a continuous glucose monitoring system (CGM).

MATERIALS AND METHODS

A consecutive series of 300 patients with Type 2 diabetes were enrolled in the study, provided that they performed blood glucose self-monitoring. HbA1c and fasting plasma glucose (FPG) were measured at enrolment.

RESULTS

Both fasting plasma and capillary glucose showed a significant correlation with HbA1c (r=0.66 and 0.61, respectively; p<0.001). When home glucose monitoring was considered, both mean fasting and post-prandial glucose showed a significant correlation with HbA1c (r=0.71 and 0.73, respectively). In patients in the lower tertile of body mass index (BMI), HbA1c showed a significant correlation at multivariate analysis with post-prandial glucose, but not with fasting glucose. In patients with HbA1c >7%, both fasting and post-prandial glucose showed a significant correlation, after adjustment for age and BMI, with HbA1c (both p<0.01); conversely, in those with HbA1c < or =7%, such a correlation could be observed for fasting (p<0.01), but not for post-prandial glucose.

CONCLUSION

In conclusion, both fasting and post-prandial glucose contribute to the determination of HbA1c . Home glucose self-monitoring appears to provide a more accurate assessment of metabolic control than a single plasma glucose measurement in experimental conditions. Fasting glucose could provide a greater contribution to HbA1c in patients with lower HbA1c, while post-prandial glucose seems to play a major role in leaner Type 2 diabetic subjects.

Involvement of D-Asp in P450 aromatase activity and estrogen receptors in boar testis

Mammalian testis contains D-aspartic acid (D-Asp), which enhances testosterone production. D-Asp, on other hand, also stimulates 17beta-estradiol synthesis in the ovary of some lower vertebrates. We studied boar testis in order to determine if D-Asp intervenes in 17beta-estradiol synthesis in the testis of those mammals which produce significant amounts of estrogens as well as testosterone. The boar testis contains D-Asp (40 +/- 3.6 nmol/g tissue) which, according to immunohistological techniques, is localized mainly in Leydig cells, and, to a lesser extent, in sustentacular (Sertoli), peritubular and some germ cells. The enzyme P450aromatase is present in Leydig cells and few germ cells. In vitro experiments showed that the addition of D-Asp to testicular tissue extracts induced a significant increase of aromatase activity, as evaluated by testosterone conversion into 17beta-estradiol. The enzyme's K(m) was not affected by D-Asp (about 25 nM in both control and D-Asp added tests). On the basis of these results we suggest that, as in the ovary, D-Asp is involved in the local control of aromatase activity of boar testis and, therefore, it intervenes in the 17beta-estradiol production. In the testis, the D-Asp targets are presumably the Leydig cells, which having also a nuclear estrogen receptor are, in turn, one of the putative targets of the 17beta-estradiol that they produce (autocrine effect).

Endogenous testicular D-aspartic acid regulates gonadal aromatase activity in boar

D-aspartic acid (D-Asp), aromatase enzyme activity and the putative D-Asp involvement on aromatase induction have been studied in the testis of mature boars. The peroxidase-antiperoxidase and the indirect immunofluorescence methods, applied to cryostat and paraffin sections, were used to evaluate D-Asp and aromatase distributions. D-Asp level was dosed by an enzymatic method performed on boar testis extracts. Biochemical aromatase activity was determined by in vitro experiments carried out on testis extracts. D-Asp immunoreactivity was found in Leydig cells, and, to a lesser extent, in germ cells. Analogously, aromatase immunoreactivity was present in Leydig cells, but absent from seminiferous tubule elements. In vitro experiments showed that the addition of D-Asp to testicular tissue acetone powder induced a significant increase of aromatase activity, as assessed by testosterone conversion to 17beta-estradiol. Enzyme Km was not affected by D-Asp (about 25 nM in control and D-Asp added tests). These findings suggest that D-Asp could be involved in the local regulation of aromatase in boar Leydig cells and intervenes in this organ's production of estrogens.

Neurotrophin-like immunoreactivity in the gut of teleost species

By means of immunochemistry and immunohistochemistry, we investigated in the gut of teleostean species the presence and localization of three neurotrophins: nerve growth factor (NGF), brain derived neurotrophic factor (BDNF) and neurotrophin (NT)-3. In all studied species both NGF- and NT-3-like immunoreactivity (IR) were present in the enteric nervous system, while BDNF-like IR was never detected. More in particular, both NGF and NT-3-like IR were detected in neurons of small and large intestine, while only NT3-like IR was also observed in stomach plexuses. Furthermore, Western blot analysis revealed the presence of molecules immunoreactive to NGF and NT-3, which weight were very similar to those of mammalian corresponding neurotrophins. These results extend to teleost species the presence and distribution of NGF- and NT-3-like IR in the enteric nervous system, suggesting a well-preserved presence of these substances in the gut during vertebrate phylogenesis.

NADPH-d positive neurons of the lizard Podarcis s. sicula oviduct and their relationship to 17beta-estradiol hormone

The distribution of nicotinamide adenine dinucleotide phosphate reduced diaphorase (NADPH-d) containing neurons was examined in the oviduct of the lizard Podarcis s. sicula and the relationship between these neurons and 17beta-estradiol hormone was studied. NADPH-d-histochemistry and indirect immunofluorescence method were applied to cryostat sections. NADPH-d-nerve structures were found throughout the oviduct. Positive neurons were primarily located in the reproductive oviduct, and were more numerous in the intermuscular and circular muscle layers than in the mucosa. The vagina revealed a reactive nerve population denser than elsewhere. The NADPH-d-positive neurons densities and the 17beta-estradiol plasma levels coincided throughout the lizard sexual cycle. In addition, after 17beta-estradiol treatments, non-reproductive lizards showed an increase of NADPH-d neurons. We suppose that nitric oxide (NO) neurons play an estrogen-dependent role in the oviduct muscle motility.

TrkA and TrkC neurotrophin receptor-like proteins in the lizard gut

The tyrosine kinase proteins (Trk), encoded by the trk family of proto-oncogenes, mediate, in mammals, the action of neurotrophins, a family of growth factors acting on the development and maintenance of the nervous system. Neurotrophins and their specific receptors, TrkA, TrkB and TrkC, seem to be phylogenetically well preserved but, in reptiles, data regarding the occurrence of Trk-like proteins are very scarce, especially in non-nervous organs. Western blot analysis demonstrated that the lizard gut contains TrkA- and TrkC-like, but not TrkB-like, proteins. Consistently, TrkA- and TrkC-like immunoreactivity were both observed in neurons of the anterior intestine, whereas endocrine cells of the stomach and anterior intestine only displayed TrkA-like immunoreactivity. These results demonstrate for the first time the occurrence of Trk-like proteins in non-neuronal tissues of reptilians and provide further evidence for the evolutionary preservation of the molecular mass and cell distribution of Trk neurotrophin receptor-like proteins in the gut of vertebrates.

The relationships of nicotinamide adenine dinucleotide phosphate-d to nitric oxide synthase, vasoactive intestinal polypeptide, galanin and pituitary adenylate activating polypeptide in pigeon gut neurons

The distribution of nicotinamide adenine dinucleotide phosphate (NADPH)-d neurons and their relationship with nitric oxide synthase (NOS), vasoactive intestinal polypeptide (VIP), pituitary adenylate activating polypeptide (PACAP) and galanin (Gal) were examined in the gastrointestinal (GI) tract of the pigeon Columbia livia. NADPH-d-histochemistry, indirect immunofluorescence and confocal analysis were applied to cryosections. Western blot analysis was also applied on pigeon gut. NADPH-d neurons were found throughout the pigeon GI tract and they were evident in the myenteric, circular muscle and submucous plexuses. Positive varicose nerve fibres were also distributed within the longitudinal muscle layers and in the lamina propria of the mucosa. The stomach was the segment richest in positivities. The copresence VIP/Gal/NOS as well as PACAP/VIP were revealed in some NADPH-d-neurons. We suppose that the nitrergic nerve population of the pigeon GI tract belong to the muscle motility regulation as an inhibitory descending nerve pathway. Moreover the presence of VIP, Gal and PACAP in some NADPH-d-containing neurons enhances the inhibitory actions of these neurotransmitters whereas PACAP and Gal role is actually unknown.

The distribution and colocalisation of nicotinamide adenine dinucleotide phosphate reduced-diaphorase (NADPH-d)-/nitric oxide synthase (NOS)-containing neurons in the innervation of the duck ureter

ensp;The distribution and colocalisation of nicotinamide adenine dinucleotide phosphate reduced-diaphorase (NADPH-d)-/nitric oxide synthase (NOS)-containing (nitrergic) neurons in the innervation of the duck ureter have been studied using histochemistry and immunohistochemistry. Quantitative analysis showed that nitrergic neurons made up 60% and 70% of the total intramural and adventitial neuronal populations, respectively. About 40% of intramural nitrergic neurons expressed VIP-immunoreactivity, and about 75% of nitrergic adventitial neurons expressed TH-immunoreactivity. The density of nitrergic adventitial neurons was significantly greater in the lower tract than in the upper and intermediate tracts. Nerve lesioning experiments showed that the majority of ureteral nitrergic innervation was extrinsic in origin; nitrergic adventitial neurons primarily projected caudocranially, whereas NOS-immunoreactive and NOS-/VIP-immunoreactive intramural neurons primarily projected craniocaudally. These findings suggest that, in birds, the nitrergic innervation plays a role in ureteral functions such as epithelial mucosecretion, muscular motility, and the closing and/or opening of the ureteral papilla.

Relationships between liver testosterone receptor isoforms and aromatase activity in female green frog, Rana esculenta

Testosterone receptors (AR) are present in the liver of the female green frog, Rana esculenta, which resolve into two fractions (A and B) by ion-exchange chromatography. Fraction A is primarily located in the nuclei, fraction B predominates in the cytosols, and both fractions show a high affinity and specificity for testosterone. Liver AR fraction levels vary dramatically during the frog sexual cycle. Fraction A levels are high only when the liver is engaged in vitellogenin production and the plasma testosterone levels are high: they are maximal when aromatase activity is most intense. Fraction B levels are high when the liver is not producing vitellogenin and the plasma testosterone levels are minimal. In addition, in vivo experiments carried out on ovariectomized females treated with testosterone show that testosterone induces both fraction A and liver aromatase activity. This induction may be a step in the process that allows the liver to obtain estrogen from plasma testosterone which induces vitellogenin synthesis.

Galanin in the lizard oviduct: its distribution and relationships with estrogen, VIP and oviposition

The distribution of neurons containing galanin immunoreactivity (Gal/IR) has been detected in the oviduct of the lizard Podarcis s. sicula during the main phases of its sexual cycle and after 17beta-estradiol treatment. Indirect immunofluorescence technique was applied both to cryostatic sections and whole mount preparations, and Western blot analysis, with an antibody directed against mammalian galanin (Gal), was performed with lizard oviduct extracts. Colocalization of Gal with vasoactive intestinal polypeptide (VIP) was also studied as well as Gal effects on egg deposition. In the quiescent oviduct of non-reproductive females, scanty Gal/IR fibres were found in the uterine-vaginal segment. During the reproductive period a gradual increase of positive nerve fibres and cell bodies were found distally in the lizard oviduct and the vagina revealed a reactive nerve population denser than elsewhere. Gal-IR nerve structures were present either in the musculature or mucosa and in the intermuscular layer they were organized in a nerve network. In the oviduct of non-reproductive females, 17beta-estradiol administration induced a significant increase of neurons containing Gal/IR. This hormone could be involved in the egg laying by means of galanin action and this hypothesis is supported by the induction of premature oviposition in pre-ovulatory females after Gal administration. Western blot analysis validates this peptide as true Gal, recognising one protein band with a molecular weight (3.2 kDa), similar to that of porcine Gal. Double labelling studies showed the co-presence of Gal and VIP in some neurons.

Galanin-containing-neurons, in the gastrointestinal tract of the lizard Podarcis s. sicula, as components of anally projecting nerve pathway

The distribution of galanin immunoreactive (Gal/IR) neurons was investigated in the gastrointestinal (GI) tract of the lizard Podarcis s. sicula. The indirect immunofluorescence method, image analysis and confocal analysis were applied to cryostat sections and whole mount preparations. Gal/IR nerve fibers and cell bodies were found throughout the lizard GI tract in the myenteric plexus, circular muscle layer and mucosa. These nerve structures decreased caudally. The stomach revealed a denser reactive nerve population than elsewhere. The projections of Gal/IR neurons were detected in the myenteric plexus of lizard gut using a confocal microscope which analyzed the immunoreactive material on the proximal and distal sides of muscle myotomies. An accumulation of Gal/IR material on the oral side of the myotomies demonstrated the oral-to-anal projection of Gal containing nerve structures. Based on our results, it can be hypothesized that Gal/IR neurons of the lizard digestive tract belong to the inhibitory descending pathway, which in most vertebrates is responsible for gut peristalsis regulation.

Trk-neurotrophin receptor-like immunoreactivity in the gut of teleost species

Neurotrophins, acting through their high-affinity signal-transducing Trk receptors, are involved in the development, differentiation and maintenance of discrete neuron populations in the higher vertebrates. Furthermore, the presence of Trk receptors in some non-neuronal tissues, including the endocrine cells of the gut, could indicate an involvement of neurotrophins also in these tissues. Recently, neurotrophins and neurotrophin receptor proteins have been identified in the lower vertebrates and invertebrates, whose amino acid sequences are highly homologous with those found in mammals. The present study investigates the occurrence and distribution of Trk-like proteins in the neurons and gut endocrine cells in five species of teleost. Single and double immunolabeling was carried out on fresh and paraffin-embedded tissue using commercially available antibodies against sequences of the intracytoplasmic domain of the mammalian Trk. Western-blot analysis, carried out on samples of stomach and intestine of bass, identified proteins whose estimated molecular masses (140 kDa, 145 kDa and 143-145 kDa) were similar to those reported for full-length TrkA, TrkB and TrkC in the higher vertebrates. TrkA-like immunoreactivity was found in the enteric nervous system plexuses of three fish species. Trk-like immunoreactivity was observed in the endocrine cells as follows: sparse TrkA-like immunoreactive endocrine cells were detected only in the intestine: TrkB-like immunoreactive cells were detected only in the stomach; and TrkC-like immunoreactive cells were found both in the intestine of the carp and in the stomach of the bass, where they also showed TrkB-like immunoreactivity. These findings confirm the occurrence and distribution of Trk-like proteins in teleosts. These proteins are closely related to the Trk neurotrophin receptors of mammals. The functional significance of Trk-like proteins in both neuronal and non-neuronal cells of teleosts is still not clear.

NADPH-diaphorase and NOS enzymatic activities in some neurons of reptilian gut and their relationships with two neuropeptides

The distribution of neurons containing the enzymes NADPH-diaphorase (NADPH-d) and nitric oxide synthase (NOS) has been studied in the gastrointestinal tract of lizard (Podarcis s. sicula) and snake (Thamnophis sirtalis). The techniques employed were the NADPH-d/nitroblue tetrazolium histochemical method, and the indirect immunofluorescence applied to cryostat sections and to whole-mount preparations. The colocalization of NADPH-d with NOS, with vasoactive intestinal polypeptide (VIP) and with galanin (Gal) was also studied, and a Western blot analysis using an antibody directed against mammalian Gal was performed on lizard stomach extracts. NADPH-d positive nerve cell bodies and fibres were found in the myenteric and submucous plexuses throughout the gastrointestinal tract of both reptiles. These nerve structures were also present in the other intramural nerve plexuses, although in smaller quantities. Both in lizard and snake, the stomach revealed a positive nerve population that was more dense than elsewhere in the gut. The population of the NADPH-d-positive neurons observed in the lizard was larger than that observed in the snake. The distribution of both populations was similar to those that have been described in the gut of several mammalian and non-mammalian vertebrates. Both in lizard and snake, a one-to-one correspondence was noted between NOS- and NADPH-d-containing nerve cell bodies, and the nitrergic neurons containing Gal appeared to be more numerous than those containing VIP. Western blot analysis recognised a single band with a molecular weight (3.4 kDa) very similar to that of porcine Gal. It is hypothesised that at least some of the nitrergic neurons of the lizard and snake gut are inhibitory motor neurons innervating the circular smooth musculature. In addition, the colocalization of NOS and VIP in neurons enhances their inhibitory action. The role of the neurons containing both NOS and Gal remains unknown.

Neuronal and non-neuronal Trk neurotrophin receptor-like proteins in Eisenia foetida (Annelida Oligochaeta)

The occurrence and distribution of Trk proteins, which are the high-affinity signal-transducing receptors for neurotrophins, have been investigated in earthworms (Eisenia foetida) using polyclonal antibodies which map within their catalytic domain. Western-blot analysis identified major protein bands whose estimated molecular masses were consistent with those of the full-length Trk proteins in vertebrates. Specific immunoreactivity for TrkA-, TrkB-, and TrkC-like was observed in neuronal populations of the dorsal cerebral, subpharyngeal and ventral cord ganglia. Furthermore, TrkA-like immunoreactivity was observed in subcutaneous neurons and nerve fibers between muscle layers in the peripheral nervous system. TrkB- and TrkC-like immunoreactivity was observed in the gut innervation. Non-neuronal expression of TrkB and TrkC proteins was found in epidermal cells, and TrkC-like immunoreactivity was detected in the gut epithelium.

IgE responses to Dermatophagoides pteronyssinus native major allergens Der p 1 and Der p 2 during long-term specific immunotherapy

We investigated by ELISA the IgE response to whole extract of the house-dust mite Dermatophagoides pteronyssinus (Dp) and to the native major allergens, Der p 1 and Der p 2, in sera from 18 adult patients (group A) with Dp-allergic asthma before (t0) and 1, 2, 3, and 4 (t1-t4) years after subcutaneous specific immunotherapy (SIT). A qualitative reduction (P = 0.05) of the IgE responses to Dp and Der p 2 was observed from t1 to t4, but a highly statistical significant decrease appeared at t3 (P < 0.01). With regard to Der p 1 IgE values, the immunotherapy induced a significant decrease (P < 0.01) at t3, but not before. In group A, the IgE responses to Der p 1 and Der p 2 were not correlated at t0 (rs = 0.31; P = 0.21) but were correlated at t3 (rs = 0.78; P = 0.001). We also examined sera from 14 adult patients (group B, same SIT schedule as group A) who were without respiratory symptoms at the end of the third year (t3) of Dp SIT. At this time (t3), there were no significant differences in Der p 1 and Der p 2 IgE levels between group A and group B.

NADPH-diaphorase-, nitric oxide synthase- and VIP-containing nerve structures in the hen oviduct: a histochemical and immunohistochemical study

The enzyme NADPH-diaphorase (NADPH-d; a marker of NO producing or nitrergic neurons) and the neuropeptide VIP have been detected in the nerve structures of the hen oviduct by histochemical and immunohistochemical techniques performed on cryostatic sections and whole mount preparations. In the upper four segments of the oviduct, i.e. the infundibulum, magnum, isthmus and shell gland, nitrergic and VIP-positive nerve structures were particularly numerous in the intermuscular and mucosal layers, and were represented by fibres and cell bodies showing mainly a perivascular distribution. Functionally, such perivascular structures were related to the blood flow regulation. Different types of nitrergic pyrenophora were recognized in the walls of the shell gland on the basis of their peculiar morphology. In the distal zone of the oviduct, the vagina, nitrergic and VIP-positive nerve fibres were widely diffused in the circular muscle, which was particularly thick in this segment. The source of at least part of such fibres was probably represented by large nerve cell bodies scattered in the layer and containing NO and VIP colocalized. Functionally these cells retained inhibitory motor neurons causing relaxation of the vaginal smooth muscle.

[A peculiar anomaly of the main biliary duct: choledochal cystic dilatation]

The Authors report a case of choledochal cystic dilatation and examine this particular anomaly of the main biliary duct analysing the complex classification. After a brief review of the embryology of the hepato-pancreatic ring, etiopathogenetic theories, clinic characteristics, as well as diagnostic and therapeutic possibilities for this affection are taken into account. It is concluded that the best therapeutic choice should be always based on an accurate evaluation of the anatomo-pathological conditions in each single case.

Characterization of uterine growth response to cholera toxin in hamsters and test of heat-labile enterotoxin from Escherichia coli

Cholera toxin (CT) and the heat-labile enterotoxin from Escherichia coli, when injected intraperitoneally into cycling hamsters but not rats or mice, induced a massive uterine growth similar to that normally induced by the implanting blastocyst during pregnancy. CT and heat-labile enterotoxin are the only known agents that have this action in any species. Uterine weight reached a maximal sixfold increase 48 h after injection of CT. Concurrent injection of estrogen, progesterone, and CT increased the maximal response to eightfold and eliminated differences in the response to CT injected on different days of the 4-day hamster estrous cycle. The dose response for CT, heat-labile enterotoxin, and CT plus estrogen plus progesterone was most linear (r greater than 0.93) when the logarithm of uterine weight was plotted against the dose of toxin. The hamster uterine weight response can serve as a simple, highly precise, and highly specific bioassay for CT and heat-labile enterotoxin.