A novel intronic mutation and a missense mutation of MEN1 identified in two Chinese families with multiple endocrine neoplasia type 1.

BACKGROUND: Multiple endocrine neoplasia type 1 (MEN1) caused by MEN1 mutation is widely recognized. To date, 14 novel mutations were reported in Chinese and intronic mutations are getting more attention. AIM: To explore clinical features and MEN1 mutations in two Chinese families suffering from MEN1. METHODS: Nineteen individuals (10 males and 9 females) from two unrelated families with MEN1 were studied. Mutations of MEN1 were analyzed by direct sequencing of PCR products. In vitro splicing analysis was also performed with minigenes containing both wildtype and novel mutant fragments. Through the RNAstructure program, we analyzed the secondary structure of the wild type MEN1 pre-mRNA and then introduced T>G mutation at +2 donor splice site of intron 7. RESULTS: Clinical features of 3 patients in two families were described, and 5 individuals were proven to be carriers of MEN1 mutation without apparent symptoms. A novel splicing site mutation of the intron 7 (IVS7+2 T→G) was identified in the first family. In vitro analysis also verified this mutation caused the aberrant splicing of MEN1 mRNA. With the RNAstructure program, we could figure out that the global secondary structure as well as the number of stems and loops of pre-mRNA greatly changed after this mutation. The mutation c. 1227 C>A (C409X) was identified in another family, which also caused the truncation of menin. CONCLUSION: We reported a novel intronic mutation and a missense mutations in two Chinese families suffering from MEN1.

Aldosterone perturbs adiponectin and PAI-1 expression and secretion in 3T3-L1 adipocytes.

Aldosterone is considered as a new cardiovascular risk factor that plays an important role in metabolic syndrome; however, the underlying mechanism of these effects is not clear. Hypoadiponectinemia and elevated circulating concentration of plasminogen activator inhibitor-1 (PAI-1) are causally associated with obesity-related insulin resistance and cardiovascular disease. The aim of the present study is to investigate the effect of aldosterone on the production of adiponectin and PAI-1 in 3T3-L1 adipocytes. Northern and Western blot analyses revealed that aldosterone treatment inhibited adiponectin mRNA expression and secretion and simultaneously enhanced PAI-1 mRNA expression and secretion in a time- and dose-dependent manner. Rosiglitazone did not prevent aldosterone's effect on adiponectin or PAI-1 expression. In contrast, tumor necrosis factor (TNF)-α produced dramatic synergistic effects on adiponectin and PAI-1 expression when added together with aldosterone. Furthermore, the effects of aldosterone on adiponectin and PAI-1 expression appear to be mediated through glucocorticoid receptor (GR) but not mineralocorticoid receptor (MR). These results suggest that the effects of aldosterone on adiponectin and PAI-1 production are one of the underlying mechanisms linking it to insulin resistance, metabolic syndrome and cardiovascular disease.

Effects of melatonin administration on plasma leptin concentration and adipose tissue leptin secretion in mice.

Both melatonin and leptin show a circadian variation in circulating levels and participate in energy metabolism. An interrelationship between these two hormones has thus been proposed. In addition, melatonin has been shown to be capable of influencing circulating leptin concentration. However, whether melatonin will increase or decrease leptin production is still uncertain. This study was undertaken to examine the effect of melatonin on leptin production using male C57BL/6 adult mice treated with or without daily melatonin supplements (10 mug/mL) in drinking water for 1 month. In addition, in vitro experiments using adipose tissue fragments derived from epididymal fat pads of adult mice incubated with or without melatonin (1 nM) administration were also conducted. The results showed that melatonin-supplemented mice had significantly higher plasma leptin levels than control mice. However, melatonin incubation did not cause any marked changes in the amount of leptin secreted from adipose tissue fragments. Our findings from this study indicate that melatonin does not affect leptin secretion via mouse adipose tissue. Nevertheless, melatonin could still influence leptinemia indirectly via regulatory effects in intact animals.

Density functional theory study of CsC(n)- (n = 1-10) clusters.

In this paper, we report the design of numerous models of CsC(n)(-) (n = 1-10). By means of B3LYP density functional method, we carried out geometry optimization and calculation on the vibrational frequency. We found that the CsC(n)(-) (n = 4-10) clusters with Cs lightly embraced by C(n) are ground-state isomers. The structures are composed of C(n)(2-) and Cs(+) with the former being electronically stabilized by the latter. When n is even, the C(n) (n = 4-10) chain is polyacetylene-like. The CsC(n)(-) (n = 1-10) with even n are found to be more stable than those with odd n, and the result is in accord with the relative intensities of CsC(n)(-) (n = 1-10) observed in mass spectrometric studies. In this paper, we provide explanations for such trend of even/odd alternation based on concepts of the highest vibrational frequency, incremental binding energy, electron affinity, and dissociation channels.

Radiation therapy with concomitant and adjuvant cisplatin and paclitaxel in high-risk cervical cancer: long-term follow-up.

INTRODUCTION: Chemo-potentiation of radiation improves survival in women with cervical cancer. Our group has previously demonstrated the tolerability of weekly paclitaxel combined with cisplatin during radiation therapy. We sought to determine the efficacy of this regimen in patients with "high risk" cervical cancer, and to determine the short- and long-term toxicity of this approach. METHODS: We prospectively enrolled surgically staged patients with positive peritoneal cytology, resectable nodal metastases, or primary tumor > 6 cm. Patients were treated using external beam radiation with concomitant cisplatin (50 mg/m2) during weeks 1, 4, and 7, and weekly paclitaxel (50 mg/m2), followed by four courses of adjuvant cisplatin (50 mg/m2) and paclitaxel (135 mg/m2). Toxicity, overall, and disease-free survival were evaluated. RESULTS: Twenty-three patients were enrolled, and 21 were evaluable. Patient allotment by FIGO stage was: IB1 - seven, IB2 - five, IIA - two, IIB - four, IIIB - two, IV - three. Twenty patients (95%) completed radiation treatment (median dose to point A was 8278 cGy). Seventeen patients (81%) completed all chemotherapy. At a median follow-up of 58 months the overall survival was 68%. Overall survival for patients with clinical Stage I and II disease was 82% at a median of 64 months. Hematologic toxicity was common but rarely resulted in treatment delays. Late complications requiring intervention (obstruction, fistula, significant lymphocyst) occurred in 11 patients (52%). CONCLUSION: The combination of paclitaxel and cisplatin appears efficacious in "high-risk" cervical cancer patients. Hematologic toxicity was common but tolerable. Long-term survival was common in these patients, however late toxicity was significant. This regimen should be investigated in collaborative phase III trials.

Low dietary zinc intake attenuates the efficacy of 2,4-thiazolidinedione on reducing hyperglycemia in db/db mice (Short communication).

Zinc (Zn) has the potential of regulating the action of thiazolidinedione (TZD), an anti-diabetic drug. Since some diabetic patients cannot achieve optimal glycemic control when receiving TZD, we investigated if Zn deficiency affects TZD's efficacy in glucose metabolism. Diabetic mice were fed diets containing 3 or 30 mg/kg Zn for 6 weeks. Thereafter, all mice were oral gavaged with 2,4-thiazolidinedione. Our results showed that blood glucose values at fasting and during the glucose tolerance test were significantly higher in low-Zn mice than those of adequate-Zn mice. Thus, low Zn intake may attenuate TZD's efficacy on reducing diabetic hyperglycemia.

Radiotelemetric monitoring of hypothalamic gonadotropin-releasing hormone pulse generator activity throughout the menstrual cycle of the rhesus monkey.

Continuous monitoring of the electrophysiological manifestations of GnRH pulse generator activity was achieved by radiotelemetry throughout the menstrual cycles of unrestrained rhesus monkeys. The characteristic increases in hypothalamic multiunit activity (MUA volleys) associated with each LH pulse measured in the peripheral circulation were of lower frequency during the luteal phase than in the follicular phase of the cycle. Multiunit activity volley frequency increased as functional luteolysis progressed and achieved maxima of approximately one volley per hour within the first few days of the follicular phase. Unexpectedly, a dramatic decline in pulse generator frequency was observed coincidentally with the initiation of the preovulatory LH surge. Evidence is presented to support the conclusion that this deceleration of pulse generator activity is the consequence of the preovulatory rise in plasma estrogen concentration. As reported in women, a significant reduction in GnRH pulse generator frequency was observed at night during the follicular phase, but not during the luteal phase, of the menstrual cycle.

Ambient light modifies gonadotropin-releasing hormone pulse generator frequency in the rhesus monkey.

In the course of previous studies using continuous monitoring of the electrophysiological correlates of GnRH pulse generator activity, characterized by episodic increases in hypothalamic multiunit electrical activity (MUA volley), it was noticed that the nocturnal slowing of pulse generator frequency was an acute phenomenon observable in the first MUA volleys after the lights were turned off, as was the increase in frequency when the lights were turned on in the morning. This suggested that the reduction in pulse generator frequency at night may not be the consequence of an intrinsic diurnal rhythm, but an effect of light per se. Indeed, as reported herein, such an effect was observed when the lights were turned on or off at times other than the normal illumination period (normal light schedule, lights on from 0700-1900 h). That this was not simply a response to arousal was shown by awakening the animals with loud recorded noises in total darkness at the same unaccustomed times without a resulting change in frequency. This suggests that the effect of light is specific, perhaps mediated by the retino-hypothalamic tract. This direct action of light, however, is superimposed upon a diurnal rhythm, as shown by a reduction in pulse generator frequency during the subjective night when the monkeys were kept in constant light or constant darkness.

The insulin hypoglycemia-induced inhibition of gonadotropin-releasing hormone pulse generator activity in the rhesus monkey: roles of vasopressin and corticotropin-releasing factor.

Insulin-induced hypoglycemia (IIH) profoundly inhibits the activity of the hypothalamic GnRH pulse generator. The aim of this study was to determine the role of vasopressin and CRF in this response. Ovariectomized rhesus monkeys with chronically implanted recording electrodes in the mediobasal hypothalamus and with intracerebroventricular (icv) cannulas in the lateral ventricle were placed in primate chairs, and blood samples were taken every 10 min. Pulse generator activity was monitored electrophysiologically by detecting characteristic increases in hypothalamic multi-unit activity (MUA volleys) and by attendant LH pulses measured in peripheral blood. Arginine vasopressin (AVP) infused via the i.c.v. cannula (50 micrograms/60 microliters.h) in eight monkeys failed to decrease pulse generator activity, as measured by the frequency of MUA volleys, but decreased mean serum LH concentrations (P < 0.001) while increasing serum cortisol levels (P < 0.02). Central administration of an AVP antagonist ([deamino-Pen1, O-Me-Tyr2-Arg8] vasopressin) in four monkeys at a rate (180 micrograms/60 microliters.h) that had previously been found to block the aforementioned effects of coadministered AVP failed to prevent the IIH-induced inhibition of GnRH pulse generator activity and LH secretion in the same animals. On the other hand, a CRF antagonist, [D-Phe12,Nle21,38,C alpha MeLeu37] rat CRF-(12-41), infused i.c.v. at a rate of 500 micrograms/60 microliters.h in four monkeys, delayed the inhibition of pulse generator frequency in response to IIH. These results suggest that AVP does not mediate the hypoglycemia-induced inhibition of GnRH pulse generator frequency in the rhesus monkey, but that CRF may be involved in this response.

On the mechanism of the positive feedback action of estradiol on luteinizing hormone secretion in the rhesus monkey.

In women and rhesus monkeys, both the negative and positive feedback actions of estradiol (E2) on gonadotropin secretion (inhibition followed by a surge) can be exerted directly at the level of the pituitary gland. We have tested the hypothesis that the positive feedback action of E2 represents but an "escape" from its negative feedback inhibition of gonadotropin secretion consequent to a desensitization of the gonadotropes occasioned by sustained exposure to elevated concentrations of the steroid. We have attempted to replicate such a desensitization by blocking the negative feedback action of E2 by the administration of a potent estrogen receptor antagonist devoid of any agonistic properties (ZM 182,780) to rhesus monkeys in the midfollicular phase of the menstrual cycle (n = 14). The estrogen antagonist, administered at a dose that in separate experiments completely blocked both the negative and the positive feedback effect of exogenous E2 on pituitary LH secretion, failed to produce a surge-like increase in serum LH concentrations. The present results do not support the hypothesis that the LH surge is the consequence of the removal of the negative feedback action of E2. Evidence is presented that ZM 182,780, in contrast to its inhibition of E2-induced LH surges, cannot block the inhibition of hypothalamic GnRH pulse generator activity by E2.

Zinc in hair and serum of obese individuals in Taiwan.

Zinc concentrations in both serum and hair were assessed in 135 obese patients (51 males, 84 females) and in 57 controls (28 males, 29 females) to study the correlation between Zn and obesity. The body mass index (wt/ht2) was also measured to evaluate its relationship to the Zn level in obese individuals. The serum and hair Zn contents in obese patients were markedly lower than in normal control subjects by 22 and 34%, respectively. The Zn content was inversely related to the body mass index. Thus Zn may play an important metabolic role in the development of obesity.

Galanin inhibits leptin expression and secretion in rat adipose tissue and 3T3-L1 adipocytes.

In addition to serving as a fat depot, adipose tissue is also considered as an important endocrine organ that synthesizes and secretes a number of factors. Leptin is an adipocyte-derived hormone that plays a vital role in energy balance. Expression of leptin is regulated by dietary status and hormones. In the present study, we report that galanin, an orexigenic peptide, inhibits leptin expression and secretion in rat adipose tissue and in 3T3-L1 adipocytes. Treatment with galanin (25 micro g/animal) induced approximately 46% down-regulation of leptin secretion at 15 min, followed by 40, 37 and 47% decreases in leptin secretion at 1, 2 and 4 h respectively. Although Northern blot analysis of adipose tissue from the same animals showed that leptin mRNA expression in adipose tissue was unaffected by galanin treatment for 2 h, galanin treatment for 4 h led to decline of leptin mRNA expression in a dose-dependent manner. Meanwhile, treating the rats with galanin had no effect on leptin mRNA expression in the hypothalamus. The inhibitory action of the galanin on leptin mRNA and protein levels was also observed in vitro. When incubated with 10 nM galanin for 48 h, leptin mRNA expression and protein secretion also decreased in 3T3-L1 adipocytes. On the other hand, galanin was found not only to express in rat adipose tissue, but also to increase about 8-fold after fasting. Based on these data, we speculate that increased galanin expression in rat adipose tissue after fasting may be involved in reducing leptin expression and secretion in fasting rats.

Mitigation of the somnolence of insulin-induced hypoglycemia by a vasopressin V1 receptor antagonist in the rhesus monkey.

Insulin-induced hypoglycemia causes somnolence in rhesus monkeys, a phenomenon usually considered an aspecific consequence of neuroglycopenia. Previous observations from our laboratory have raised the possibility that arginine vasopressin (AVP) may also play a role in this decrease in wakefulness. In the present study we tested this hypothesis by inducing hypoglycemia (approximately 40 mg/dl) in ovariectomized rhesus monkeys by intravenous administration of insulin in the presence of continuous intracerebroventricular infusions of the V1 receptor antagonist [deamino-Pen1, O-Me-Tyr2,Arg8]-vasopressin (180 micrograms/60 microliters per h) or of its vehicle alone (artificial cerebrospinal fluid, 60 microliters/h). Wakefulness was assessed by a scoring system by observers blinded to the experimental protocol. The AVP antagonist significantly attenuated the decrease in wakefulness observed in response to insulin-induced hypoglycemia (p < .03) without increasing blood glucose levels. These and previous findings suggest that the somnolence induced by a moderate degree of hypoglycemia may not entirely be the direct consequence of neuroglycopenia and that AVP may, directly or indirectly, be involved.

Effects of selected minerals on leptin secretion in streptozotocin-induced hyperglycemic mice.

The effects of lithium, magnesium, vanadate, and zinc on leptinemia and leptin secretion by adipose tissue were investigated in streptozotocin- (STZ) induced hyperglycemic mice. After the administration of studied minerals in drinking water for 4 weeks, fasting serum leptin concentrations were elevated, accompanied by normoglycemia in STZ-injected mice, regardless which mineral was provided (P < 0.05). However, the in vitro administration of lithium, magnesium, and vanadate did not significantly influence the leptin secretion of adipose tissue. A low zinc treatment (0.1 mM) augmented, whereas both a pharmacological treatment of zinc (1 mM) and zinc depletion (1 mM TPEN) attenuated, leptin secretion (P < 0.05). The present study shows that STZ-induced hyperglycemic mice have hypoleptinemia and reduced leptin secretion by adipose tissue. Moreover, these defects can be improved by a moderate zinc administration.

Zinc may be a mediator of leptin production in humans.

Obese individuals have hyperleptinemia and hypozincemia. Moreover, leptin and zinc have circadian changes in circulating concentrations. We investigated their possible interaction and examined whether a difference existed between obese men and their lean controls. The results indicated the pattern of circadian change in plasma zinc and leptin did not markedly differ between the obese subjects and the lean controls. However, the obese had higher leptin and lower zinc plasma values at each sampling time than did the lean controls. Because an inverse correlation was found in plasma values between zinc and leptin (r=-0.51, p=0.012), we further determined the role zinc might play in leptin production by human subcutaneous adipose tissue from female donors. The in vitro study showed that zinc treatment (0.2 mmol/L) significantly increased leptin production (142%), however, this increment did not surpass that by insulin (10 nmol/L). The data of this study suggest an interactive connection between zinc and leptin.

Plasma status of selected minerals in hypertensive men with and without insulin resistance.

The altered plasma statuses of selected minerals (Ca, Mg, Cu, Zn) have been noted in a cluster of insulin resistance syndromes, including hypertension and diabetes mellitus. The differences in plasma values of these minerals in hypertensive men with and without insulin resistance, as evaluated by an insulin suppression test, were investigated. The results showed that the plasma values of determined minerals at fasting, 2 h after an oral glucose challenge, and after the insulin suppression test did not markedly differ between hypertensive subjects with and without insulin resistance. However, hypertensive subjects had significantly lower plasma Ca values at fasting and 2 h after an oral glucose load, and higher fasting plasma Zn values, than normotensive controls. Hypertensive subjects also had higher steady-state plasma glucose values, higher Zn and lower Mg and Cu values after the insulin suppression test, when compared with controls. The present study suggests that altered plasma status of selected minerals in hypertension cannot be totally ascribed to the co-exhibition of insulin resistance.

Gastric carcinoma presenting as an exacerbation of ulcers during pregnancy. A case report.

Gastric cancer is unusual during pregnancy. Also, because of the physiologic changes that occur with pregnancy, it is rare to see a worsening of peptic ulcers during pregnancy. A patient with an exacerbation of peptic ulcers presented with gastric carcinoma during pregnancy.

Zinc and nitric oxide synthase inhibitor L-NAME attenuate NPY-induced feeding in mice.

The influences of zinc (Zn) and the nitric oxide synthase (NOS) inhibitor L-NAME on peripheral neuropeptide Y (NPY)-induced feeding in mice were investigated. Male mice received NPY (200 ng/d/mouse subcutaneously) and were separated into four groups based on cotreatments (with or without Zn [0.1 mg/mL]) and with or without L-NAME [0.2 mg/mL]) administered in drinking water for 10 d. A control group that received saline injection was also studied. The results showed that NPY, with or without any studied chemicals, did not affect body weight gain or body fat content. However, the mice that were administered NPY alone had increased energy intakes, higher serum triglyceride and free fatty acid, and lower serum glucose than saline-injected controls. NPY-treated mice that were given Zn and L-NAME cotreatments had compatible results of determined variables in comparison with control mice. This study showed that Zn and L-NAME attenuated NPY-mediated feeding and selected serum variables in mice. However, the mechanisms of the interactions among NPY, Zn and NOS, and their effects on appetite regulation, remain to be elucidated.

Zinc supplementation aggravates body fat accumulation in genetically obese mice and dietary-obese mice.

A perturbation of zinc metabolism has been noted in numerous laboratory animals with diabetes and obesity. The effects of zinc supplementation on body fat deposition in two types of experimental obese mice: genetically obese (ob/ob) mice and high-fat diet-induced ICR obese (HF) mice were investigated in this study. Their lean controls were +/? mice, and ICR on basal diet, respectively. The mice in the zinc-supplemented groups were administered 200 mg/kg zinc in their diets for 6 wk. Both the ob/ob mice and the HF mice, that were fed a diet containing a marginal zinc dosage (4-6 mg/kg), had lower zinc levels in their serum and carcass, and higher body fat content than their respective lean controls (p < 0.01). After zinc supplementation, ob/ob mice and the HF mice significantly (p < 0.05) increased their body fat by 49.4% and 18.9%, respectively. This study revealed that body fat deposition can be aggravated by zinc supplementation in both types of obese mice. Zinc may be associated with the energy homeostasis of obesity, via its interaction with dietary fat consumption.

Zinc status in plasma of obese individuals during glucose administration.

To know whether plasma zinc status is altered under acute hyperglycemic state, the interrelationships among plasma glucose, insulin, and zinc concentrations during oral glucose tolerance test (OGTT) in obese individuals and their lean controls were studied. Plasma glucose and insulin concentrations under fasting as well as those values in response to OGTT were significantly higher in obese individuals than those in lean controls. On the other hand, the obese had lower fasting plasma zinc concentrations compared to lean controls (13.5 vs 18.1 mumol/L, p < 0.005). Under fasting, plasma zinc concentrations in overall individuals inversely correlated to their body mass index (BMI) (r = -0.516), plasma glucose (r = -0.620), and plasma insulin (r = -0.510). However, there were no significant changes in plasma zinc and copper values during OGTT in both obese individuals and lean controls. This study showed that plasma zinc values had no changes during OGTT in obese individuals. The results also indicated that lower fasting plasma zinc concentrations in obese individuals were not the short-term metabolic result.