Allelic loss of chromosome 6q in gastric carcinoma.

Loss of the long arm of chromosome 6 (6q) has frequently been reported in gastric carcinoma, and most gastric cancer patients have evidence of intestinal metaplasia in the stomach. However, the relationship between loss of chromosome 6q and intestinal metaplasia has not been studied. In the first part of the study, we define the critical deletion region of chromosome 6q using loss of heterozygosity technique (LOH). Seventeen microsatellite markers were used to detect loss of heterozygosity (LOH) in 37 microdissected gastric tumors. We also examined intestinal metaplasia (IM) foci of the stomach in the same cancer patient (17 cases). Losses on chromosome 6q were detected in high frequency (51%) by LOH. Two distinct regions of common allelic loss were identified: one centered on the marker D6S300 (at 6q16.1) and the second on D6S446 (at 6q27), with LOH frequency of 36% and 31.3%, respectively. The deletions fall into 2 discrete regions, suggesting the existence of at least 2 tumor suppressor genes in 6q. The losses at 6q27 were confirmed by fluorescence in situ hybridization study (FISH). In the cases with LOH in the tumor, no LOH were detected in the autologous IM areas, but losses were detected by FISH. In some cases, these genetic changes may be acquired in the transition from normal gastric mucosa to intestinal metaplasia.     

Specific biochemical markers of bone metabolism and cytokine study confirm the diagnosis of malignant infantile osteopetrosis at birth using cord blood sample

AIMS: To investigate the serum creatine kinase isoenzyme pattern, specific biochemical markers of bone metabolism, and cytokines in a Chinese family with osteopetrosis, and correlate abnormalities with the pathophysiology of this condition. METHODS: A Chinese female baby was diagnosed with malignant infantile osteopetrosis at the age of 3 weeks by clinical history and biochemical investigations. We studied the laboratory and radiological manifestations of this index case and her family members. RESULTS: Serum CK-BB fraction of our index patient was elevated to 18.0% (normal 1.6-7.6%). Her biochemical markers of bone resorption including serum C-terminal telopeptide concentration and urine N-terminal telopeptide to creatinine ratio were decreased to 0.54 microg/L (normal 0.72-1.56 microg/L) and 159 x 10(-6) (normal 372-900 x 10(-6)), respectively. Serum cytokines including soluble receptor activator of nuclear factor kappa-B ligand (sRANKL) concentration was suppressed to 0.11 pmol/L (normal 0.23-0.82 pmol/L) and osteoprotegerin (OPG) concentration was 4.9 pmol/L (normal 2.8-4.9 pmol/L), resulting in an elevated OPG to sRANKL ratio of 44.5 (normal 3.8-19.4) in favour of bone formation. CONCLUSIONS: If left untreated, this condition is usually fatal within the first year of life. With early diagnosis, management including bone marrow transplantation can be planned ahead and will result in a better survival.     

Power spectral analysis of the electroencephalographic and hemodynamic correlates of propofol anesthesia in the rat: Intravenous infusion

Based on the tail-flick response to noxious thermal stimuli, we determined in the present study that effective antinociception could be achieved in adult male Sprague-Dawley rats 15 min after intravenous infusion of propofol at 60 mg/kg/h. Simultaneous power spectral analysis of the electroencephalographic (EEG) and systemic arterial pressure signals further revealed a concomitant depression of the activity of all EEG frequency bands (δ, θ, , β), alongside hypotension, negative inotropic and chronotropic actions, and attenuated baroreceptor reflex and vasomotor activity. These effects were congruent with a plasma concentration of propofol in the arterial blood of 1.70 ± 0.13 μg/ml, as determined by high-performance liquid chromatography.     

Reduction in baroreceptor reflex response by angiotension III and its modification by Ile7-angiotensin III and bestatin in the rat

We evaluated the participation of endogenous brain angiotensin III (AIII) in central cardiovascular regulation, using the intracerebroventricular injection technique in Sprague-Dawley rats anesthetized with pentobarbital sodium (50 mg/kg, i.p.). AIII (100 pmol) promoted an elevation in systemic arterial pressure and a reduction in the baroreceptor reflex (BRR) response. Its specific antagonist, Ile7-AIII (100 nmol), and the aminopeptidase inhibitor, bestatin (200 nmol), on the other hand, augmented the response of the same reflex. The suppressive action of AIII (100 pmol) on the BRR was attenuated, and the enhancing effect of Ile7-AIII (100 nmol) was potentiated, however, when these two peptides were administered simultaneously with bestatin (200 nmol). All these events were significantly different from their controls during the first 10-15 min following injection, parallel to the time course of a discernible action of AIII on systemic arterial pressure. We discussed that the endogenous AIII in the central nervous system may participate in cardiovascular control by tonically inhibiting the BRR, in concert with other brain neuropeptides.     

A study on Epstein Barr Virus receptor activity in cell free extracts of human lymphoblastoid cells

Summary Epstein Barr Virus (EBV) receptor activity in cell free extracts is operationally defined as one which causes a reduction in the effective concentration of the early antigen inducing particles of an EBV preparation when the latter is preincubated with the extract before infection. Such activity was detected in the surface extract of Raji cells and to a lesser extent in that of BJAB cells, both of which are B lymphoblastoid cells that are susceptible to infection with EBV. Receptor activity was not detected in similar extracts of P₃HR-1 cells and human diploid fibroblasts neither of which are known to be susceptible to EBV infection.Receptor activity in the Raji cell extract was found to be associated with membranous structures. This may have rendered the activity resistant to treatment with trypsin and sonication. The activity was however abrogated if the extract was exposed to neutral detergent.Binding of receptor activity was observed when Raji cell extract was chromatographed on a column of immobilized EBV. Subsequent electrophoretic analysis showed however that this procedure did not result in an appreciable purification of the receptor activity. Neutral detergent treated extract was similarly chromatographed. The resulting eluates did not contain detectable receptor activity but were less heterogeneous in protein content as compared with that of the original extract. It is not certain at present if these EBV binding proteins are involved in the receptor activity of the extract.With 3 Figures     

Case report: human herpesvirus 7 associated fatal encephalitis in a peripheral blood stem cell transplant recipient

Previous studies have suggested a neuroinvasive and neuropersistent potential of human herpesvirus 7 (HHV-7). In this report, a case of fatal encephalitis is described and its association with HHV-7 infection is discussed. An 8-year-old girl received a peripheral blood stem cell transplant for relapsed acute lymphoblastic leukaemia. The post-transplant period was uneventful and a course of intrathecal chemotherapy was given on Day-30. On Day-41, she developed acute encephalopathy with diplopia and nystagmus. She ran a rapid downhill course and succumbed despite antiviral treatment. The only positive pathological finding was the multiple microscopic foci of haemorrhage associated with neuronal degeneration detected in the brain stem. All microbiological investigations were negative, except for the presence of HHV-7 DNA in cerebrospinal fluid and brain stem tissue samples.     

Amino acid supplementation improves cell-specific functions of the rat hepatocytes exposed to human plasma

Maintaining hepatocyte function during plasma exposure is critical for the successful development of hepatocyte-based bioartificial liver assist systems. Past attempts to culture hepatocytes in plasma yielded discouraging results. Using a stable culture model based on sandwiching hepatocytes between two layers of collagen gel, we investigated the effect of hormone and amino acid supplementation during exposure of rat hepatocytes to heparin-treated human plasma for 1 week. Morphology and hepatocyte-specific functions were evaluated for hepatocytes cultured in Dulbecco's Modified Eagle medium (DMEM), nonsupplemented plasma, plasma supplemented with hormones, or with hormones plus amino acids. Amino acids were supplemented at four-fold concentration of Basal Medium Eagle with 4 mM glutamine, whereas hormones included 7.5 microg/mL of hydrocortisone and 50 microU/mL of insulin. Cuboidal structure and bile canaliculi formation were observed throughout the 1-week exposure period for control hepatocytes in DMEM and for hepatocytes cultured in hormone supplemented plasma. Albumin and urea synthesis rates of hepatocytes in hormone plus amino acid supplemented plasma during the last day of plasma exposure were 60.4 +/- 13.7 and 75.6 +/- 6.5 (microg/day per 1 x 10(6) cells, mean +/- SD), respectively, comparable to cultures in standard culture medium. On the other hand, hepatocytes exposed to nonsupplemented plasma suffered significant morphological and functional damage. The results of this study indicate that hormone plus amino acid supplementation help to restore function in hepatocytes exposed to plasma.     

Familial hyperinsulinemia due to a structurally abnormal insulin. Definition of an emerging new clinical syndrome

We have identified a patient with mild diabetes, marked fasting hyperinsulinemia (89 to 130 microU of insulin per milliliter), and a reduced fasting C-peptide: insulin molar ratio of 1.11 to 1.50 (normal, greater than 4). The patient responded normally to exogenous insulin. However, her endogenous immunoreactive insulin showed reduced biologic activity during a glucose-clamp study with hyperglycemia and a reduced ability to bind to the insulin receptor and stimulate glucose transport in vitro. Family studies showed that five additional relatives in three generations had variable degrees of glucose intolerance, marked hyperinsulinemia, and a reduced peripheral C-peptide:insulin molar ratio. Restriction-endonuclease cleavage of DNA isolated from circulating leukocytes in the patient and in family members with hyperinsulinemia revealed loss of the MboII recognition site in one allele of the insulin gene--consistent with a point mutation at position 24 or 25 in the insulin B chain. Other studies using high-pressure liquid chromatography and detailed gene analysis have identified the defect as a serine for phenylalanine substitution at position 24 of the insulin B chain. The secretion of a structurally abnormal insulin should be considered in patients with hyperinsulinemia who respond normally to exogenous insulin and have a reduced C-peptide:insulin molar ratio. Glucose tolerance may range from relatively normal to overtly diabetic.     

Interleukin-1β and anaphylatoxins exert a synergistic effect on NGF expression by astrocytes

C3a and C5a anaphylatoxins are proinflammatory polypeptides released during complement activation. They exert their biological activities through interaction with two G protein-coupled receptors named C3aR and C5aR, respectively. In the brain, these receptors are expressed on glial cells, and some recent data have suggested that anaphylatoxins could mediate neuroprotection. In this study, we used RT-PCR and ribonuclease protection assays (RPA) to investigate the role of anaphylatoxins on neurotrophin expression by the human glioblastoma cell line T98G and by rat astrocytes. Our data show that for both cell types, anaphylatoxins upregulate expression of NGF mRNA. This response depended on a G protein-coupled pathway since pre-treatment of cells with pertussis toxin (PTX) completely blocked NGF mRNA increases. This effect was anaphylatoxin-specific since pre-incubation with anti-C3a or anti-C5aR antibodies abolished the effects of C3a and C5a, respectively. The regulation of NGF mRNA by anaphylatoxins was not accompanied by translation into protein expression, but there was a significant synergic effect of anaphylatoxins/IL-1b costimulation. Our demonstration of involvement of anaphylatoxins in the NGF release process by astrocytes suggests that C3a and C5a could modulate neuronal survival in the CNS.