Abstract P4-04-03: PIK3CA mutations in breast tumor specimens in a cohort (n=791) of a multicentric study and associations to known prognostic factors and survival data

Introduction:

The PI3K/AKT/mTOR signalling pathway plays an important role in cellular processes like proliferation, apoptosis, survival and adhesion of tumor cells. It is one oft the most deregulated pathways in cancer.

In up to 30% of breast cancers, dysregulation of this pathway is reported, resulting from mutations in the PIK3CA gene that encodes the catalytic subunit (p110a). Hotspots of mutations, comprising 86 % of all observed PIK3CA-mutations, were described in exon 9 (helical domain, E542K, G > A; E545K, G > A) and exon 20 (kinase domain, H1047R, A > G). Prevalence and the prognostic impact of the PIK3CA mutations as well as the predictive value with regard to endocrine therapy are controversially discussed.

In this study we describe the prevalence of the three most frequent PIK3CA mutations in a consecutive cohort of breast cancer patients and its association to tumor characteristics, to known prognostic factors and survival data.

Methods:

The cohort consists of 1,047 patients who were newly diagnosed for non-metastatic breast cancer in one of 6 German breast centres from 2009 to 2011 and who were registered within the prospective PiA-study (Prognostic assessment in routine Application, NCT 01592825). DNA of 806 fresh frozen tumors were available for analyzation by qPCR (exon 9: C 763 and C760; exon 20: C 775).

Associations between the PIK3CA mutation status and clinical, pathological parameters were evaluated using binary logistic regression model. Survival probabilities were estimated by Kaplan-Meier-method, Log-Rank-Test and Breslow-Test. Recurrence free interval (RFI) was defined according to STEEP criteria.

Results:

Mutation status for the three most common PIK3CA mutations was available for 791 tumors. The mutation rate was 29.2%. Only two tumors harbored two mutations (C 765, C 763). Tumors with a PIK3CA mutation were significantly more frequent in HR positive tumors (32%; p=0,001), in HER2 negative tumors (31%, p=0,010) and in tumors with low or intermediate histological grade (39%; 32% resp., each p<0,001). In triple negative tumors, PIK3CA mutations were found in 13%. There was no significant association to age, menopausal status, tumor size, nodal status and uPA/PAI-1 status.

Tumors with a PIK3CA mutation showed a slightly better recurrence-free interval (93.6%, CI 93.2-94.01 vs. 90.3%, CI 89.9-90.7). We found a prognostic impact on RFI after 5 ys F/U in patients with HR-negative tumors (93% vs 71%) and those with TNBC (100% vs. 70%).

Conclusion:

PIK3CA mutations occur frequently in breast cancer tumors. We found a prognostic impact only in patients with HR-negative and TNBC tumors.

This data adds important information to the heterogeneous results of other previously published patient cohorts. In summary in our study, tumors that harbour a mutation of the PIK3CA-gene, were associated to prognostically more favorable factors and a better recurrence-free intervall.

Citation Format: Reinhardt K, Thomssen C, Volker H, Tilmann L, Christoph U, Susanne P, Jutta J, Joerg B, Edith W, Karl-Friedrich B, Eva Johanna K, Martina V. PIK3CA mutations in breast tumor specimens in a cohort (n=791) of a multicentric study and associations to known prognostic factors and survival data [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-04-03.

Endothelial dysfunction in metabolic diseases: role of oxidation and possible therapeutic employment of N-acetylcysteine

Several metabolic diseases present a high cardiovascular mortality due to endothelial dysfunction consequences. In the last years of the past century, it has come to light that the endothelial cells, previously considered as inert in what regards an eventual secretion activity, play a pivotal role in regulating different aspects of the vascular function (endothelial function). It was clearly demonstrated that the endothelium acts as a real active organ, owning endocrine, paracrine and autocrine modulation activities by means of which it is able to regulate the vascular homeostasis. The present review will investigate the relationship between some metabolic diseases and the endothelial dysfunction and in particular the mechanisms underlying the effects of metabolic pathologies on the endothelium. Furthermore, it will consider the possible therapeutic employment of the N-acetilcysteine in such conditions.

Electrocatalysts for methanol oxidation based on platinum/carbon nanofibers nanocomposite

New carbon nanomaterials, i.e., carbon nanotubes and nanofibers, with special physico-chemical properties, are recently studied as support for methanol oxidation reaction electrocatalysts replacing the most widely used carbon black. Particularly, carbon fibrous structures with high surface area and available open edges are thought to be promising. Platelet type carbon nanofibers, which have the graphene layers oriented perpendicularly to the fiber axis, exhibit a high ratio of edge to basal atoms. Different types of carbon nanofibers (tubular and platelet) were grown by plasma enhanced chemical vapour deposition on carbon paper substrates. The process was controlled and optimised in term of growth pressure and temperature. Carbon nanofibers were characterised by high resolution scanning electron microscopy and X-ray photoelectron spectroscopy to assess the morphological properties. Then carbon nanofibers of both morphologies were used as substrates for Pt electrodeposition. High resolution scanning electron microscopy images showed that the Pt nanoparticles distribution was well controlled and the particles size went down to few nanometers. Pt/carbon nanofibers nanocomposites were tested as electrocatalysts for methanol oxidation reaction. Cyclic voltammetry in H2SO4 revealed a catalyst with a high surface area. Cyclic voltammetry in presence of methanol indicated a high electrochemical activity for methanol oxidation reaction and a good long time stability compared to a carbon black supported Pt catalyst.

Prolonged treatment with N-acetylcysteine and L-arginine restores gonadal function in patients with polycystic ovary syndrome

Nitric oxide (NO) plays a wide spectrum of biological actions including a positive role in oocyte maturation and ovulation. Free radicals levels have been shown elevated in polycystic ovary syndrome (PCOS) and therefore would be responsible for quenching NO that, in turn, would play a role in determining oligo- or amenorrhea connoting PCOS. Eight patients with PCOS displaying oligo-amenorrhea from at least 1 yr underwent a combined treatment with N-acetylcysteine (NAC) (1200 mg/die) plus L-arginine (ARG) (1600 mg/die) for 6 months. Menstrual function, glucose and insulin levels, and, in turn, homeostasis model assessment (HOMA) index were monitored. Menstrual function was at some extent restored as indicated by the number of uterine bleedings under treatment (3.00, 0.18-5.83 vs 0.00, 0.00-0.83; p<0.02). Also, a well-defined biphasic pattern in the basal body temperature suggested ovulatory cycles. The HOMA index decreased under treatment (2.12, 1.46-4.42 vs 3.48, 1.62-5.95; p<0.05). In conclusion, this preliminary, open study suggests that prolonged treatment with NAC+ARG might restore gonadal function in PCOS. This effect seems associated to an improvement in insulin sensitivity.

N-acetylcysteine is able to reduce the oxidation status and the endothelial activation after a high-glucose content meal in patients with Type 2 diabetes mellitus

Post-prandial hyperglycemia seems to play a pivotal role in the pathogenesis of the cardiovascular complications of diabetes mellitus, as it leads to an oxidative stress which in turn causes a reduced NO bioavailability. These conditions produce an endothelial activation.

AIM OF THE STUDY

The aim of this study was to assure that the administration of N-acetylcysteine (NAC), thiolic antioxidant, is able to decrease the oxidation status and endothelial activation after a high-glucose content meal.

SUBJECTS AND METHODS

Ten patients with Type 2 diabetes mellitus (DMT2) (Group 1) and 10 normal subjects (Group 2) were studied. They assumed a high-glucose content meal without (phase A) or after (phase B) the administration of NAC. Glycemia, insulinemia, intercellular adhesion molecule 1, vascular adhesion molecule 1 (VCAM-1), E-selectin, malonaldehyde (MDA), and 4-hydroxynonenal (HNE) were assessed at -30, 0, +30, +60, +90, +120, and +180 min with respect to the meal consumption.

RESULTS

During the phase A in Group 1, only HNE and MDA levels increased after the meal assumption; all parameters remained unchanged in Group 2. During the phase B, in Group 1, HNE, MDA, VCAM-1, and E-selectin levels after the meal were lower than those in phase A, while no change for all variables were observed in Group 2.

CONCLUSIONS

A high-glucose meal produces an increase in oxidation parameters in patients with DMT2. The administration of NAC reduces the oxidative stress and, by doing so, reduces the endothelial activation. In conclusion, NAC could be efficacious in the slackening of the progression of vascular damage in DMT2.

Development of an electronic tongue based on a PEDOT-modified voltammetric sensor

Three different electrodes were tested for use as nonspecific amperometric sensors for blind analysis on real matrices, namely different fruit juices from different fruits or different brands. The first two electrodes were traditional Pt and Au electrodes, while the third one was modified with poly(3,4-ethylenedioxythiophene) conducting polymer. The sensors were tested separately, tested coupled to each other, and also tested together. The responses of the electrode system(s) were first screened via PCA and then their discriminant capabilities were quantified in terms of the sensitivities and specificities of their corresponding PLS-DA multivariate classification models. Particular attention was paid to analyzing the evolution of the response over subsequent potential sweeps. The modified electrode demonstrated the most discriminating ability, and it was the only system capable of satisfactorily performing the most complex task attempted during the analysis: discriminating between juices from the same fruit but from different brands. Moreover, the electrode "cleaning" procedure required between two subsequent potential sweeps was much simpler for the modified electrode than for the others. This electrode system was therefore shown to be a good candidate for use as an informative element in an electronic tongue applied to the analysis of other food matrices.

[Renal tubular transport and genetic hypotension]

The progressive improvement of genetic research technologies has led to the identification of different genes involved in blood pressure regulation. Renal regulation systems of sodium homeostasis play a key role. Mutations capable of determining an increase or a decrease in carrier proteins function could cause not only hypotension or hypertension, but also the related metabolic symptoms and changes, and the possible response to pharmacologic treatment. Monogenic forms of hyper- or hypotension are rare, though they highlight the importance of sodium tubular transport in blood pressure adjustment.

Platelet cGMP inversely correlates with age in healthy subjects

Biochemical modifications associated with the increase in platelet activity with age are not well defined. Furthermore it is well known that the nitric oxide/cyclic 3', 5'-guanosine monophosphate (cGMP) pathway regulates platelet aggregation. The aim of the present study was to examine the relationship between platelet content of cGMP and age. 120 normal subjects, evaluating the cGMP platelet concentration, 17betaE2, IGF-I, dehydroepiandrosterone sulphate (DHEAS), insulin, plasma glucose, lipid pattern, homocysteine and PAI-I antigen, were studied. The multivariate analysis in a model with cGMP as dependent variable and with age, LDL, apolipoprotein B (ApoB), DHEAS, E2 and insulin-like growth factor (IGF)-I as independent variables shows a negative correlation between cGMP and age (p<0.01, beta=-0.388). In conclusion our data suggest that the reduced efficiency of the system constitutive nitric oxide synthase (cNOS)/guanylate cyclase represents at least one of the reasons of the increased platelet aggregability with age.

Sweat function in the diabetic foot

BACKGROUND

Autonomic dysfunction, an early manifestation of diabetic neuropathy, presents with altered sweating patterns, leading to dryness and fissuring. We conducted a study to assess the sweat function in the diabetic foot and to determine the interrelation between the duration of diabetes, sensation, fissuring, and sweating.

METHODS

The sweat function was assessed in 30 diabetic patients, 28 of whom had fissuring of the feet, using Ninhydrin impregnated discs.

RESULTS

There was a significant association between fissuring and sensation, but not between the duration of diabetes and fissuring and between loss of sweating and fissuring. In 18 patients (60%) there was impairment or absence of sweating in the presence of normal sensation.

CONCLUSION

Although fissuring increases with long-standing diabetes and sweating is reduced in diabetic patients with fissures on the foot, the correlation between these entities was not statistically significant. Since 60% patients had altered sweating in the presence of normal sensations, the sweat test can be used as an early indicator of diabetic neuropathy.

Platelet cyclic guanosine monophosphate production during menstrual cycle in healthy women

The incidence of cardiovascular disease among women during their reproductive years is considerably less than in men and this difference decreases after menopause. Since in cultured endothelial cells and in platelets E2 increases nitric oxide (NO) production, it is possible that their cardioprotective effect may be mediated by NO. The aim of this study was to evaluate platelet cyclic guanosine monophosphate (cGMP), as a marker of NO production, during menstrual cycle. Fifteen women aged 26-40 yr were studied to evaluate: LH, FSH, E2, P and cGMP on the 5th follicular and 22nd luteal day of the cycle and during the ovulatory period. Platelet cGMP was evaluated in basal condition (3-isobuthyl 1-methylxanthine-IBMX) and with ionomycine (IONO) and sodium nitroprusside (SNP).

RESULTS

LH, FSH, E2 and P demonstrated the typical patterns of ovulatory cycle. During follicular and luteal IBMX, SNP and IONO phase were homogeneous while they increased during the ovulatory period. A correlation between IBMX cGMP and E2 (p<0.002, rs=0.456) was found. In conclusion the data show an increase in platelet cGMP during the ovulatory period and a correlation between E2 and cGMP suggesting that E2 modulates NO production. The cardioprotective effect of E2 may be, at least in part, mediated by the increase in NO production.

Serum DHEAS levels correlate with platelet cGMP in normal women

Several studies suggest that DHEAS is a protective factor against atherosclerosis and coronary artery disease in man, but the mechanism of its biological role is unclear. Recently, it has been suggested that DHEAS can retard atherosclerosis formation through an increase in nitric oxide (NO) production by increasing E2 synthesis. The aim of the study was to evaluate the platelet cGMP concentrations (i.e. a marker of NO production) and the serum levels of DHEAS and E2 in normal females. Blood samples were taken from 51 normal women (age 42.3+/-1.9 yr, range: 22-67 yr, BMI 23.0+/-0.6 kg/m2) to evaluate platelet cGMP concentrations and serum levels of DHEAS and E2. To determine the platelet cGMP content, platelet rich plasma (PRP) was incubated at 37 C (30 min) in the presence of IBMX. The amount of platelet cGMP was measured by a cGMP (3H) assay kit. In all subjects the mean of platelet cGMP was 536.2+/-45.3 fmol/10(6) platelets and the mean of serum DHEAS and E2 was 151.4+/-13.9 microg/dl and 34.7+/-6.1 pg/ml, respectively. In all subjects DHEAS positively correlates with cGMP (p<0.001, r=0.513) and with E2 (p<0.001, r=0.650); furthermore E2 positively correlates with cGMP (p<0.001, r=0.663). In conclusion our data support the hypothesis that DHEAS exerts its antiatherogenic effect by increasing the NO production directly and/or by increasing the E2 synthesis.

Administration of glutathione in patients with type 2 diabetes mellitus increases the platelet constitutive nitric oxide synthase activity and reduces PAI-1

Several studies suggest that nitric oxide (NO) production is impaired in diabetes mellitus. Reduced levels of NO could contribute to cardiovascular mortality. Furthermore, NO synthesis is impaired in glutathione (GSH)-depleted human umbilical vein endothelial cells and GSH is reduced in patients with type 2 diabetes mellitus (T2DM). We tested the hypothesis that treatment with GSH may improve platelet constitutive NO sinthase (cNOS) activity in patients with T2DM. Fifteen patients with T2DM underwent a treatment with GSH 600 mg/day i.m. for 10 days. With respect to the basal values on the 10th day of treatment, the red blood cell GSH concentration and platelets cNOS increased (1.4+/-0.1 vs 1.9+/-0.1 micromol/10(10) RBC, p<0.001 and 0.7+/-0.1 vs 2.9+/-0.2 fmol x min(-1) x 10(-9) PLTs, p<0.001, respectively) and the plasma PAI-1 levels diminished (81.4+/-3.7 vs 68.7+/-4.0 ng/ml, p<0.002). A negative correlation between the cNOS and the PAI-1 was found on the basal values. After a wash-out of 30 days the values of red blood cell GSH concentration, platelet cNOS activity and PAI-1 Ag returned to the basal levels. These data suggest that the administration of GSH, in patients with T2DM, is able to improve platelet cNOS activity together with a reduction of PAI-1.

Bone metabolism in type 2 diabetes mellitus

Several conditions have been described to cause osteoporosis, including diabetes mellitus. While the relationship between type 1 diabetes and osteopenia is well documented in the literature, data on the presence of this complication in type 2 diabetes have not been well established. We studied a population composed of 66 post-menopausal women with type 2 diabetes and a control population. We examined bone mineral density with the dual-energy X-ray absorptiometry (DXA) technique at the lumbar and femoral levels and, in a subgroup of patients, we also measured the levels of markers of bone remodelling. We found significantly higher levels of bone mineral density at the femoral (but not lumbar) level in the diabetic subjects compared with the control population in all the examined subregions, except Ward's triangle. Moreover, we found higher levels of some markers of bone resorption (urinary calcium and hydroxyproline, telopeptide) in the patients with diabetes, while urinary crosslinks were higher in the controls. On the basis of these results, we suggest that osteoporosis cannot be considered a complication of type 2 diabetes and that, from a metabolic point of view, bone resorption is greater in diabetic patients than in normal subjects, as suggested by the high levels of most of the markers of osteoclastic activity.

Platelet cNOS activity is reduced in patients with IDDM and NIDDM

Several studies in vitro and in vivo suggest that the nitric oxide (NO) production is impaired in diabetes mellitus. Reduced levels of NO could contribute to vascular alteration facilitating platelet-vascular wall interaction, adhesion of monocytes to endothelium, vascular smooth muscle proliferation and by decreasing endothelium-dependent vasodilation. In this study we evaluated the activity of the constitutive nitric oxide synthase (cNOS) in platelets of patients with insulin-dependent diabetes mellitus (IDDM) and with non-insulin-dependent diabetes mellitus (NIDDM). When compared to that of normal subjects, cNOS activity is significantly lower in patients with IDDM and with NIDDM (1.57 +/- 0.25 vs. 0.66 +/- 0.10 fmol/min/10(9) PLTs and 1.57 +/- 0.25 vs. 0.67 +/- 0.08, respectively; p<0.005). These data demonstrate that the platelet cNOS activity is decreased in diabetes mellitus.

Calcium blood level modulates endogenous nitric oxide action: effects of parathroidectomy in patients with hyperparathyroidism

Platelet cyclic guanosine monophosphate (cGMP) is produced by soluble guanylate cyclase (sGC), the activity of which is modulated by the activity of nitric oxide (NO) constitutive synthase (cNOS) which, in turn, is activated by a calcium/calmodulin complex. In primary hyperparathyroidism (H-PTH) an increase in platelet free calcium levels is present. In this study we evaluate the platelet cGMP levels, as an expression of NO production, in the presence of 3-isobutyl-1-methylxanthine (IBMX) alone (IBMXcGMP) and after stimulation by ionomycine (IONO; IONOcGMP) and sodium nitroprusside (SNP; SNPcGMP), in eight subjects affected by H-PTH before and after removal of adenoma. Platelet cGMP levels were also measured in seven normal subjects. IBMXcGMP and IONOcGMP were elevated in H-PTH patients compared with normal subjects (1.9 +/- 0.3 vs 0.8 +/- 0.2 fmol/10(6) platelets and 2.7 +/- 0.4 vs 1.4 +/- 0.3; P < 0.02 and P < 0.05 respectively) but SNPcGMP was unaffected (3.9 +/- 0.6 vs 2.5 +/- 0.5). After parathyroidectomy, blood levels of intact parathyroid hormone (i-PTH), total calcium (t-Ca), IBMXcGMP and IONOcGMP all decreased (177.5 +/- 23.9 vs 45.0 +/- 8.8 pg/ml, P < 0.005; 6.5 +/- 0.5 vs 4.6 +/- 0.1 mEq/1, P < 0.005; 1.9 +/- 0.3 vs 0.8 +/- 0.2, P < 0.005; 2.7 +/- 0.4 vs 1.8 +/ 0.3, P < 0.05 respectively), while SNPcGMP was not modified (3.9 +/- 0.6 vs 4.3 +/- 0.9). t-Ca and i-PTH were directly correlated with IBMXcGMP (P < 0.02, rs = 0.613; P < 0.02, rs = 0.576 respectively) and i-PTH was also correlated with t-Ca (P < 0.001), rs = 0.840).

IN CONCLUSION

(1) levels of IBMXcGMP and IONOcGMP are high in subjects with H-PTH; (2) after surgery both IBMXcGMP and IONOcGMP decrease to normal values. As IBMXcGMP expresses basal cGMP and IONOcGMP expresses the cGMP after cNOS stimulation, it can be speculated that the increase in NO production could be a mechanism to downregulate the vasoconstriction which may be caused by the high calcium levels in smooth muscle cells. After surgery, together with the normalization of calcium levels, NO production also returned to normal values.

The altered plasma amino acid pattern is responsible for the paradoxical growth hormone response to the oral glucose tolerance test in liver cirrhosis

OBJECTIVE

An increased basal growth hormone (GH) secretion and a parodoxical GH response to the oral glucose tolerance test (OGTT) have been reported in patients with liver cirrhosis. It has been suggested that the ratio between branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs) (BCAA/ AAA ratio) may determine in part the brain concentration of the AAAs, since the BCAAs compete with the AAAs for entry across the blood-brain barrier, leading to the accumulation of false neurotransmitters such as octopamine and phenylethanolamine, which are able to stimulate GH secretion (via alpha 2-adrenergic stimulation). In this study we investigated the role of amino acids, particularly the BCAA/AAA ratio, in the paradoxical response of GH to the OGTT in patients with liver cirrhosis.

PATIENTS AND DESIGN

Twelve non-diabetic patients with biopsy-proven cirrhosis of the liver underwent an OGTT. Three of the five patients with a paradoxical response of GH to the OGTT underwent a second oral glucose administration associated with an infusion of BCAA solution from -30 min until 180 min.

RESULTS

During the OGTT, glucose and insulin levels increased from 4.8 +/- 0.2 to 9.6 +/- 0.7 mmol/l (P < 0.001) and from 18.8 +/- 2.6 to 104.4 +/- 13.8 mU/l (P < 0.005), respectively. GH levels increased from 8.6 +/- 2.6 to 22.4 +/- 10.8 mU/l although not significantly. Five patients had a paradoxical GH response to the OGTT. A negative correlation between serum GH values and BCAA/AAA ratio in the plasma at every time point of the OGTT was found. After co-administration of glucose and BCAA in three patients the BCAA/AAAs ratio increased, abolishing the paradoxical GH secretion.

CONCLUSIONS

Our data suggest that in liver cirrhosis the altered BCAA/AAA ratio may influence the altered basal GH secretion and the paradoxical GH response to the OGTT, probably by an increase of adrenergic mediators in the brain. Moreover, the increase of BCAA/AAA ratio seems to be able to abolish the GH paradoxical response to the OGTT.

Repeated administration of growth hormone-releasing hormone with or without previous administration of pyridostigmine in insulin-dependent diabetes mellitus

In insulin dependent diabetes mellitus (IDDM) either elevated growth hormone (GH) levels or abnormal responses to specific as well as unspecific stimuli have been reported. As hyperglycemia is known to blunt GH response to various stimuli, a normal GH response to GHRH in presence of hyperglycemia should also be considered inappropriate. To investigate the mechanism underlying this inappropriate GH response, in 9 patients with IDDM, selected for normal GH response to GHRH, we studied the GH response to two consecutive GHRH boluses (1 microgram/kg), the second of which preceded 30 min before by pyridostigmine (120 mg p.o.). Seven age matched normal volunteers were evaluated as control group. Basal plasma glucose and serum GH levels were significantly higher in patients with IDDM than in normal subjects (184.4 +/- 9.6 vs 86.2 +/- 4.4 mg/dl, p < 0.01 and 2.4 +/- 1.0 vs 1.0 +/- 0.4 microgram/l, p < 0.01 respectively). Both in normal subjects and in patients with IDDM the GH response to the second consecutive GHRH administration was lower than that of the first GHRH bolus (delta AUC: 82.5 +/- 28.3 vs 401.1 +/- 131.2 micrograms/l/h, p < 0.05 and 77.2 +/- 30.4 vs 336.8 +/- 60.0 p < 0.02, respectively). Pyridostigmine was able to restore the blunted GH responsiveness to the second GHRH administration in both groups, but this response was found higher in normal than in diabetic subjects (delta AUC: 1250.8 +/- 136.2 vs 527.5 +/- 147.6, p < 0.01). Since the GH-releasing effect of PD is likely to be mediated by the inhibition of hypothalamic somatostatin release, our results suggest that there is also an impaired somatostatin tone in hyperglycemic type 1 diabetic patients with normal GH response to GHRH.

Clinical and genetic variability in XX sex-reversed patients

Three 46, XX hypogonadal subjects are described who exhibited different clinical and genetic characteristics. Two patients, with complete sex-reversal, are sterile males with hypogonadal features; the third patient, with partial sex-reversal, presented with a eunuchoid appearance and with ambiguous genitalia. Polymerase chain reaction (PCR) amplification of DNA from these patients showed the presence of a translocation of the sex-determining region of the Y chromosome (Sry) only in the first two patients described.

Multiple endocrine neoplasia (MEN IIB) with Cushing's syndrome due to medullary thyroid carcinoma producing corticotropin-releasing hormone

We describe a case of Cushing's syndrome caused by a medullary thyroid carcinoma (MCT) secreting corticotropin-releasing-hormone (CRH) in a young woman presenting mucosal neuromas located on the top of the tongue and eyelid areas. Laboratory studies showed, basally and after dexamethasone suppression test, serum cortisol and plasma pituitary corticotrophin (ACTH) levels agreed with an ectopic Cushing's syndrome. Immunohistochemical studies of the MCT tissue revealed a production of CRH and scattered cells containing vasopressin but not ACTH peptides. This is the first demonstrated case of a CRH-secreting tumor in multiple endocrine neoplasia (MEN IIB) syndrome.

Blunted GH response to growth hormone-releasing hormone (GHRH) alone or combined with arginine in non-insulin-dependent diabetes mellitus

An increased spontaneous and stimulated growth hormone (GH) secretion is well documented in insulin-dependent diabetes mellitus. On the contrary, in non-insulin-dependent diabetes mellitus (NIDDM) conflicting results arise from literature. In 14 patients with NIDDM, 7 normal weight (NWD) and 7 obese (OD), we investigated the somatotrope responsiveness to GHRH (1 microgram/kg) alone or combined with arginine (ARG, 0.5 g/kg), which is able to enhance the GH response to GHRH, probably by inhibiting somatostatin release from hypothalamus. Baseline IGF-I, IRI FFA and glucose levels were also determined. Twelve healthy normal subjects (NS) and 12 obese patients (OP) were evaluated as control groups. GH but not IGF-I levels were higher (p < 0.05) in NS than in OP (1.5 +/- 0.5 vs 0.5 +/- 0.2 microgram/l). Insulin levels were higher (p < 0.05) in OP than in NS, NWD and OD (18.7 +/- 1.8 vs 8.7 +/- 0.5, 6.4 +/- 1.9 and 11.8 +/- 1.2 microU/l). FFA were higher (p < 0.05) in NWD. OD and OP than in NS (0.69 +/- 0.04, 0.70 +/- 0.04 and 0.65 +/- 0.06 vs 0.39 +/- 0.03 mmol/l). Plasma glucose was higher (p < 0.05) in diabetic patients than in normal and obese subjects. GH responses to GHRH in NWD, OD and OP were similar (AUC: 221.6 +/- 33.3, 206.0 +/- 35.9 and 177.2 +/- 57.3 micrograms/l/min, respectively) and all lower (p < 0.05) than that in NS (776.7 +/- 206.5 micrograms/l/min). ARG determined a significant increase of GHRH-induced GH release in all groups (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Pirenzepine decreases basal and stimulated GH secretion in patients with type 2 (non-insulin-dependent) diabetes mellitus

Growth hormone (GH) hypersecretion has been described in diabetes mellitus and seems to be involved in the pathogenesis of diabetes complications. As pirenzepine (PZ), a cholinergic muscarinic antagonist, is able to inhibit GH hypersecretion in insulin-dependent diabetes mellitus (IDDM), we investigated whether PZ is also able to inhibit spontaneous and stimulated GH-release in non-insulin-dependent diabetes mellitus (NIDDM). Ten non-obese well-controlled patients with NIDDM underwent in random order the following three double-blind one week treatments: placebo (PL), PZ at low dose (PL in the morning plus PZ 50 mg at 22 h) or high dose (PZ 50 mg at 8 h plus 100 mg at 22 h). Pirenzepine administration significantly (p < 0.05) decreased nocturnal GH release after both low and high dose (AUC, PL vs PZ: 107.3 +/- 26.5 vs 48.3 +/- 10.5 and 57.6 +/- 9.6 micrograms/L/h, respectively). The GH response to arginine infusion was significantly inhibited by PZ at high dose (AUC, 147.1 +/- 48.8 vs 444.7 +/- 194.3 micrograms/L/h, p < 0.01), but not at low dose. Glucose, insulin, glucagon and somatostatin responses to arginine infusion were not changed by pirenzepine treatment. In conclusion, the muscarinic blockade by PZ is able to inhibit the spontaneous and stimulated GH secretion also in NIDDM without affecting insulin secretion.

Interaction of free fatty acids and arginine on growth hormone secretion in man

We studied the interaction between free fatty acids (FFAs) and arginine (ARG) on basal and growth hormone (GH)-releasing hormone (GHRH)-stimulated GH secretion in 14 normal subjects. Compared with placebo, ARG induced a significant increase of GH secretion (334.0 +/- 157.5 v 36.9 +/- 27.6 micrograms/L/h, P < .05). The increased levels of FFAs (1.9 +/- 0.4 mEq/L), obtained by the infusion of a lipid-heparin emulsion, abolished the effect of ARG (55.8 +/- 45.6 v 334.0 +/- 157.5 micrograms/L/h, P < .05). GHRH-induced GH secretion was potentiated by ARG (2,009.9 +/- 463.2 v 922.0 +/- 244.4 micrograms/L/h, P < .05) and suppressed by lipid-heparin infusion (106.2 +/- 28.3 v 922.0 +/- 244.4 micrograms/L/h, P < .01). Moreover, the lipid-heparin infusion inhibited the potentiating effect of ARG on the GHRH-induced GH increase (527.9 +/- 113.6 v 2,009.9 +/- 463.2 micrograms/L/h, P < .01). These results confirm the strong inhibitory effect of FFAs on GH secretion, showing that they are even able to inhibit the potentiating effect of ARG on the GH response to GHRH. Since ARG likely acts via inhibition of hypothalamic somatostatin release, the inhibitory effect of FFAs on GH secretion could take place directly at the pituitary level and/or at the hypothalamic level, counteracting the effect of ARG.

Inhibition by salbutamol of GHRH-induced GH release in type 1 diabetes mellitus

Patients with type 1 diabetes mellitus (IDDM) show augmented GH secretion, which is implicated in the pathogenesis of microvascular complications. On the other hand, it is well known that beta-adrenergic receptors have inhibitory influence on GH secretion, likely via stimulation of hypothalamic somatostatin. Since the possibility of pharmacological suppression of GH secretion would be of value in IDDM, we investigated the effect of salbutamol (SAL, 4 mg orally at -60 min) on the GH response to GHRH (1 micrograms/kg iv at 0 min) in 6 well-controlled (mean HbA1c +/- SEM: 7.3 +/- 0.5%) patients with IDDM. Salbutamol was able to inhibit basal GH levels (p < 0.05) as well as to abolish the GHRH-induced GH rise. After SAL administration, a significant (p < 0.05) reduction of glucagon levels was also found. Our data show that the enhancement of beta 2 adrenergic activity by oral therapeutical doses of SAL inhibits basal and GHRH-stimulated GH secretion in patients with IDDM.

Interactions of galanin and arginine on growth hormone, prolactin, and insulin secretion in man

Galanin (GAL), a 29 amino acid neuropeptide, is known to increase both basal and growth hormone-releasing hormone (GHRH)-induced growth hormone (GH) secretion while not significantly increasing prolactin (PRL) secretion in man. GAL is also endowed with an inhibiting effect on glucose-stimulated insulin release in animals, but not in man. We studied the effect of GAL (80 pmol/kg/min infused over 60 minutes) on the arginine- (ARG, 30 g infused over 30 minutes) stimulated GH, PRL, insulin, and C-peptide secretion in eight healthy volunteers (age, 20 to 30 years). GAL induced an increase of GH (GAL v saline, area under curve [AUC], mean +/- SEM: 316.5 +/- 73.9 v 93.2 +/- 20.9 micrograms/L/h, P less than .05), but failed to modify both PRL and insulin secretion. GAL enhanced the ARG-induced stimulation of both GH (1,634.1 +/- 293.1 v 566.9 +/- 144.0 micrograms/L/h, P less than .02) and PRL secretion (1,541.9 +/- 248.8 v 1,023.8 +/- 158.7 micrograms/L/h, P less than .02). On the contrary, GAL blunted the ARG-stimulated insulin (816.3 +/- 87.7 v 1,322.7 +/- 240.9 mU/L/h, P less than .05), as well as C-peptide secretion (105.1 +/- 9.8 v 132.8 +/- 17.3 micrograms/L/h, P less than .02). ARG administration induced a transient increase of glucose levels (P less than .01 v baseline) followed by a significant decrease (P less than .05 v baseline). This latter effect was prevented by the coadministration of GAL. In conclusion, these results show that in man GAL potentiates the GH response to ARG, suggesting that these drugs act at the hypothalamic level, at least in part, via different mechanisms.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of Monotard and Ultratard insulin at bedtime in a model of optimized insulin therapy in Italy

The italian habit of having a low calorie breakfast suggests an insulin treatment made up of two daily injections of soluble insulin before lunch and dinner, adding at bed time an injection of retard insulin. Aim of this study was to verify whether Monotard or Ultratard proved more effective as retard insulin in this regimen. Sixteen insulin-dependent diabetics treated with the above-mentioned insulin regimen were studied for 16 weeks. They were divided in two groups: group 1 was treated initially with Ultratard and group 2 with Monotard, with a cross-over after 8 weeks. The metabolic control achieved with the treatment was considered good with either retard insulin used. HbA1c, fructosamine, body weight and glycemic values measured after 8 and 16 weeds failed to reveal any differences between the treatment with Monotard on Ultratard. Either Monotard or Ultratard can be successfully used as bedtime retard insulin in this multiple injection insulin treatment.

Chronic treatment with pirenzepine decreases growth hormone secretion in insulin-dependent diabetes mellitus

We and others previously reported that nocturnal GH secretion in patients with insulin-dependent diabetes mellitus is blunted by acute cholinergic muscarinic blockade with pirenzepine. In this study, we investigated whether this inhibitory effect on GH secretion persists during chronic pirenzepine administration, and if pirenzepine administration affects glycemic control. Nocturnal GH secretion was studied from 2300-0800 h before and after one month of pirenzepine administration (100 mg/day, orally, given at 2300 h) in 13 diabetic patients receiving their usual insulin treatment. GH secretion (GH area under curve) was blunted after pirenzepine administration [mean, 877 +/- 215 (+/- SE) vs. 1407 +/- 311 micrograms/L.min; P less than 0.002]. During pirenzepine administration, hemoglobin A1c significantly decreased (P less than 0.02), and 4 of the 13 patients had lower daily insulin requirements (5-23 U/day), but there was no significant change for the group as a whole. These results indicate that the inhibitory effect of pirenzepine on GH secretion persists when pirenzepine is given chronically and that pirenzepine seems to improve the metabolic control of the patients.

Insulin binding to monocytes and in vivo peripheral insulin sensitivity are normal in Graves' disease

Insulin resistance in hyperthyroidism seems to depend on increased glucose production rather than on decreased glucose utilization. A decreased insulin binding on different target cells has been reported in patients in whom an in vivo evaluation of peripheral insulin sensitivity was lacking. In 20 patients with Graves' disease (6 males, 14 females), aged 40.0 +/- 2.0 yr, BMI 23.7 +/- 0.7, and in 20 well-matched controls we performed the following tests: 75 g o.G.T.T., euglycemic-hyperinsulinemic clamp at 50 microU/ml combined with D-[3-3H] glucose infusion in tracer amounts, in vitro insulin binding on circulating monocytes. Fasting plasma glucose values were similar in the two groups, whereas plasma insulin values were significantly higher in hyperthyroids (21.4 +/- 2.5 vs 10.6 +/- 0.6 microU/ml, p less than 0.01). The values of peripheral glucose utilization (5.61 +/- 0.24 vs 6.01 +/- 0.22 mg/kg-min) and of total specific insulin binding (4.07 +/- 0.20 vs 4.39 +/- 0.23% bound to 10(7) cells/ml) were not significantly different in the two groups. These results indicate that in vitro and in vivo data, when recorded in the same patients, are concordant to confirm a normal peripheral tissue sensitivity to insulin in Graves' disease.

Glucagon-induced increase in plasma potassium levels in type 1 (insulin-dependent) diabetic subjects

To investigate the hypothesis that in Type 1 (insulin-dependent) diabetes the increase in plasma potassium during decompensation may be due to a rise in glucagon concentrations, we have measured plasma glucose, potassium and glucagon levels in five diabetic patients during two tests with 0.154 mol/l saline or somatostatin (500 micrograms/h) performed on two successive days. The patients were maintained normoglycaemic overnight by means of a continuous insulin infusion. After insulin withdrawal during the saline infusion, glucose and potassium levels rose markedly (delta maximum: glucose, 12.0 +/- 1.5 mmol/l; potassium, 0.73 +/- 0.12 mmol/l), while glucagon showed a slight, but significant increment (delta maximum: 10.6 +/- 1.0 pmol/ml, p less than 0.05). The potassium increment was not mediated by a reduction in blood pH. Somatostatin abolished the rise in glucagon concentration and simultaneously markedly inhibited the rise in potassium and glucose levels. It is concluded that in acute insulin deficiency, glucagon could be one of the factors that contributes to hyperkalaemia.

Practolol inhibition of some salbutamol-induced metabolic and hormonal responses

The effect of practolol (a selective beta1-adrenergic receptor blocking agent) on increased blood insulin, sugar, lactate and FFA and decreased blood phosphorus and potassium induced by salbutamol (a primarily beta2-adrenergic stimulant) was studied in 6 normal volunteers. Practolol abolished the rise of lactate and glucose, suggesting that changes in these parameters due to salbutamol are mediated by beta1-receptors. The rise of insulin and the fall of potassium were only partially inhibited, and the possible involvement of the beta2-receptors as well in these 2 cases cannot be ruled out. The decrease of phosphorus and the FFA rise were not affected and thus appear to be primarily dependent on beta2-receptors.

Some metabolic and hormonal effects of salbutamol in man

The effect of i.v. infusion of a beta-adrenergic stimulant, salbutamol on blood insulin, glucose, lactate, phosphates, potassium and NEFA was studied in 9 normal subjects. The effect of the drug on the blood sugar and insulin response to i.v. glucose was also examined in 4 subjects. Salbutamol was followed by increases in insulin, glucose and lactate, and a fall in blood phosphorus and potassium. NEFA values did not change significantly. These effects of salbutamol were abolished by propranolol and may thus be attributed to its beta-adrenergic stimulating action. Salbutamol also induced a reduction in glucose tolerance, in spite of the presence of enhanced blood insulin levels.