Effect of dietary protein on Masheri-induced drug metabolising enzymes

The modulation of drug metabolising enzymes by Masheri extract (ME) and Benzo(a)Pyrene [B(a)P] was studied in male Sprague Dawley rats fed different dietary protein levels. Two groups of 21 days old male Sprague Dawley rats were put on a high protein diet (SHP) with 20% Casein, and a low protein diet (SLP) with 3% Casein semisynthetic based diets for 12 weeks. The SLP fed animals showed lower basal levels of the Phase I activating enzymes viz. Cytochrome P450, Benzo(a)Pyrene hydroxylase, Benzphetamine demethylase and Phase II glutathione detoxification system viz. Glutathione (GSH) and Glutathione-S-transferase. ME and B(a)P treatment significantly depleted the glutathione detoxification system in the SLP group whereas an opposite effect was observed in the SHP group. Interstingly, ME and B(a)P treated rats in the SLP group showed a higher percent increase in the hepatic and pulmonary Phase I enzyme activities than those observed in the treated ME/B(a)P treated SHP rats. Furthermore, both ME and B(a)P significantly decreased the hepatic pool of vitamin A while a concomittant increase in that of vitamin C was observed.     

Heterogeneity of binding sites for ICI 198,615 in human lung parenchyma.

We have identified and characterized two different subclasses of binding site for the novel peptido-leukotriene (LT) antagonist, [3H]ICI 198,615, in membranes from human lung parenchyma using a receptor-ligand assay. This novel compound is representative of a new class of LT receptor antagonists and it has been demonstrated to be several orders of magnitude more potent and selective than most other LT antagonists described to date. The binding of [3H]ICI 198,615 is rapid, specific and saturable. Equilibrium was reached within 5-10 min. Non linear fitting of dissociation time courses has revealed the presence of two different components (K(off)1 = 8.3 +/- 6.8 x 10(-4) sec-1 and K(off)2 = 0.79 +/- 1.66 x 10(-3) sec-1) of the kinetic curves, suggesting heterogeneity of the binding sites. Computer analysis of equilibrium binding data obtained at 25 degrees results in a model with two classes of binding sites, a high affinity-low capacity class with Kd1 = 0.024 +/- 0.014 nM and Bmax1 = 0.015 +/- 0.004 pmol/mg protein and a low affinity-high capacity class with Kd2 = 6326 +/- 3859 nM and Bmax2 = 473 +/- 383 pmol/mg protein. In competition studies, LTD4 was also found to interact with two classes of binding site (Kd1 = 0.016 +/- 0.008 nM and Kd2 = 15195 +/- 8965 nM). On the contrary, LTE4 and LTC4 were found to interact with a homogeneous class of sites only with Kd = 7466 +/- 4629 nM and Kd = 428 +/- 73 nM, respectively. Furthermore, we have evaluated the effect of a number of LT antagonists on the binding of [3H]ICI 198,615. Ro 24-5913 (Kd = 3.0 +/- 2.1 nM), FPL55712 (Kd = 4945 +/- 2868 nM), LY171883 (Kd = 19628 +/- 12365 nM), SKF 104353 (Kd = 74.2 +/- 46 nM) and its enantiomer SKF 104373 (Kd = 13627 +/- 6813 nM) were found to interact with a single class of binding sites. The present studies indicate a heterogeneity of binding sites for ICI 198,615 in membranes from human lung parenchyma and that ICI 198,615 is a very potent and selective antagonist of LTD4 receptors in this tissue.     

Classical and anaplastic seminoma: difference in survival

Classical and anaplastic seminoma are traditionally treated with radiation therapy and are said to have the same prognosis. A retrospective study was undertaken of 90 seminoma patients treated with radiation therapy between 1961 and 1985. The classical group consisted of 71 patients of whom 50 had stage I and 21 had stage II disease. The anaplastic group consisted of 19 patients of whom ten had stage I and nine had stage II disease. The median follow-up time was 64 months for the entire group. The 10-year relapse-free survival rate for the classical group was 94% and for the anaplastic group was 70% (P less than .05). For patients with classical stage I disease, the relapse-free actuarial survival rate was 98%; for patients with anaplastic stage I disease, it was 64% (P less than .02). For the classical stage II disease group, the relapse-free actuarial survival rate was 84% and for the anaplastic stage II disease group, 75% (P less than .70). Four patients in the classical group (6%) had relapses; of these, one patient had local recurrence of tumor, and three had distant metastases. In the anaplastic group, four patients (21%) had relapses; two patients had local recurrence of tumor, and two had distant metastases. Therefore the data suggest a difference in survival and relapse rates between classical and anaplastic seminoma.     

BRCA2与LIM结构域蛋白FHL2的相互作用

目的：应用酵母双杂交方法筛选BRCA2相互作用蛋白编码基因，验证其相互作用并研究其功能联系。方法：以BRCA2基因3′端片段构建酵母双杂交质粒，筛选正常人乳腺上皮细胞cDNA库，获得编码相互作用蛋白的基因，采用免疫共沉淀、哺乳细胞双杂交和荧光酶测定等方法进一步验证蛋白间相互作用和功能联系．结果：采用酵母双杂交系统筛选，获得了多个编码BRCA2相互作用蛋白的基因，其中包括已知的FHL2蛋白；免疫共沉淀和哺乳动物细胞双杂交试验显示BRCA2和FHL2在体内特异性结合，并证实FHL2在体内形成同源二聚体；转录活性分析发现BRCA2与FHL2有协同转录激活作用。结论：发现BRCA2与FHL2蛋白间相互作用和功能联系，为BRCA2功能研究提供了新的方向。     

Decrease in rat brain calcitonin binding sites and adenylyl-cyclase activity during ageing.

In order to investigate the effects of ageing on the cerebral receptors for calcitonin (CT), we used an in vitro autoradiographic method to study the distribution of the binding sites for eel CT (eCT) in young and old rat brain. The inhibitory action of eCT on adenylyl-cyclase (AC) activity upon isolated brain cell membranes was also evaluated. The results show area-specific reduction of binding particularly in the hypothalamus and pons medulla of the old rat. The inhibitory action of eCT on AC activity was significantly reduced in the same areas, whereas in the striatum and mesencephalon no changes were observed. The parallel decrease of binding of eCT and of the inhibitory action of eCT on AC in ageing may represent a functional decline of neuronal activities during ageing.     

Study on tissue concentrations of antibiotics: bacampicillin in gingiva and maxillary bones

21 patients, whose age ranged from 17 to 60 years and who had not been previously treated with antibiotics or other drugs, received bacampicillin as a perioperative prophylaxis for minor operations in the oral cavity. Four oral doses of bacampicillin were administered: each dose of 800 mg every 12 h, and the last dose was administered 2 h before surgery. To assess bacampicillin serum concentrations two blood samples were collected from each patient: the first sample was obtained 1 h before surgery and the second one during surgery. Together with the second blood sample, small quantities of gingiva and bone were obtained from each patient to also assess the antibiotic concentrations in these tissues (microbiological method). The results show that bacampicillin reaches high concentrations in both the blood and tissues studied by us, and that a direct correspondence exists between blood and gingival and bone tissue concentrations. Furthermore, it should be noted that no postoperative infections developed in our patients. These results lead to the conclusion that bacampicillin appears to be a suitable drug in the therapy of dental infections.     

Dual effects of melatonin on barbiturate-induced narcosis in rats

Melatonin affects the circadian sleep/wake cycle, but it is not clear whether it may influence drug-induced narcosis. Sodium thiopenthal was administered intraperitoneally into male rats pre-treated with melatonin (0.05, 0.5, 5 and 50 mg/kg). Melatonin pre-treatment affected in a dual manner barbiturate narcosis, however, no dose-effect correlation was found. In particular, low doses reduced the latency to and prolonged the duration of barbiturate narcosis. In contrast, the highest dose of melatonin (50 mg/kg) caused a paradoxical increase in the latency and produced a sustained reduction of the duration of narcosis, and a reduction in mortality rate. Melatonin 0.5 and 5 mg/kg influenced the duration but not the latency of ketamine- or diazepam-induced narcosis. Thus, the dual action of melatonin on pharmacological narcosis seems to be specific for the barbiturate mechanism of action.     

Mutation spectrum and genotype-phenotype analyses in Cowden disease and Bannayan-Zonana syndrome, two hamartoma syndromes with germline PTEN mutation

The tumour suppressor gene PTEN , which maps to 10q23.3 and encodes a 403 amino acid dual specificity phosphatase (protein tyrosine phosphatase; PTPase), was shown recently to play a broad role in human malignancy. Somatic PTEN deletions and mutations were observed in sporadic breast, brain, prostate and kidney cancer cell lines and in several primary tumours such as endometrial carcinomas, malignant melanoma and thyroid tumours. In addition, PTEN was identified as the susceptibility gene for two hamartoma syndromes: Cowden disease (CD; MIM 158350) and Bannayan-Zonana (BZS) or Ruvalcaba-Riley-Smith syndrome (MIM 153480). Constitutive DNA from 37 CD families and seven BZS families was screened for germline PTEN mutations. PTEN mutations were identified in 30 of 37 (81%) CD families, including missense and nonsense point mutations, deletions, insertions, a deletion/insertion and splice site mutations. These mutations were scattered over the entire length of PTEN , with the exception of the first, fourth and last exons. A 'hot spot' for PTEN mutation in CD was identified in exon 5 that contains the PTPase core motif, with 13 of 30 (43%) CD mutations identified in this exon. Seven of 30 (23%) were within the core motif, the majority (five of seven) of which were missense mutations, possibly pointing to the functional significance of this region. Germline PTEN mutations were identified in four of seven (57%) BZS families studied. Interestingly, none of these mutations was observed in the PTPase core motif. It is also worthy of note that a single nonsense point mutation, R233X, was observed in the germline DNA from two unrelated CD families and one BZS family. Genotype-phenotype studies were not performed on this small group of BZS families. However, genotype-phenotype analysis inthe group of CD families revealed two possible associations worthy of follow-up in independent analyses. The first was an association noted in the group of CD families with breast disease. A correlation was observed between the presence/absence of a PTEN mutation and the type of breast involvement (unaffected versus benign versus malignant). Specifically and more directly, an association was also observed between the presence of a PTEN mutation and malignant breast disease. Secondly, there appeared to be an interdependent association between mutations upstream and within the PTPase core motif, the core motif containing the majority of missense mutations, and the involvement of all major organ systems (central nervous system, thyroid, breast, skin and gastrointestinal tract). However, these observations would need to be confirmed by studying a larger number of CD families.