Strychnine-blocked glycine receptor is removed from synapses by a shift in insertion/degradation equilibrium

The long-term inhibition by strychnine of glycine receptor activity in neurons provokes the receptor's selective intracellular accumulation and disappearance from synapses. This could result either from a disruption of the postsynaptic anchoring of the receptor or from an arrest of its exocytic transport. In this study we combined biochemical and fluorescence microscopy analyses to determine on a short time scale the fate of the strychnine-inactivated glycine receptor. Quantification of the cellular content of receptor showed that the rapid accumulation depends on protein synthesis. Cell surface biotinylation of neurons demonstrated that strychnine did not accelerate the turnover rate of the receptor. Labeling of endosomes indicated that, in strychnine-treated cells, the accumulated receptor is not blocked in the endosomal transport pathway. Taken together, these results indicate that strychnine does not destabilize the postsynaptic receptor but triggers its disappearance from synapses by a nondegradative sequestration of newly synthesized molecules in a nonendocytic compartment.     

A BRCA1/2 mutation,high breast density and prominent pushing margins of a tumor independently contribute to a frequent false-negative mammography

Female BRCA1/2 mutation carriers develop in up to 50% breast cancer (BC) before age 50 years. We investigated whether the specific histologic features of BRCA1/2-associated breast cancer influence imaging. We correlated the mammographic results with the histology of 34 BC in BRCA1/2 mutation carriers and 34 sporadic cancers in patients, matched for age and year of diagnosis. Mammography was significantly more frequently false-negative in carriers than controls (62% vs. 29% p = 0.01), despite comparable tumor size (mean solidus in circle 1.51 vs. 1.75) and breast density (high 41% vs. 53%). The image in carriers was significantly less as spiculated mass (6 vs. 18 p = 0.01). Cancers of BRCA1/2 mutation carriers had frequently higher mitotic counts (p < 0.0001) and prominent pushing margins around the tumor (p = 0.08) (p = 0.05 for 32 BRCA1). We also observed that prominent "pushing margins" correlated significantly with a false-negative mammography (p = 0.005) and with a mammographic image of a smooth, not a spiculated, mass (p = 0.01). False-negative mammography correlated independently with: BRCA1/2 mutation (p = 0.02), prominent pushing margins (p = 0.03) and high breast density (p = 0.01). MRI was carried out in 12 carriers, had 100% sensitivity and detected 5 cancers, still occult at physical examination and mammography. A BRCA1/2 mutation and high breast density at mammography contribute independently to false-negative mammography results. In mutation carriers any mammographic mass must be regarded with suspicion. Pushing margins of the tumor partly explain these results. For early BC detection in mutation carriers additional methods like MRI may be needed. This may not be necessary in other young women with breast symptoms.     

Allelic deletions of Rb and L-myc in urine sediments from patients with bladder tumors or carcinoma in situ

In a previous study we found allelic imbalances of Rb and L-myc associated with disease stage and disease course in bladder cancer. The primary aim of the present study was to determine whether the changes found in tumors were reflected in urine sediments. Secondly we wanted to test if Rb and L-myc were frequently lost in urine sediments from patients with carcinoma in situ and no bladder tumor at present. Based on this we examined allelic deletions of the Rb and L-myc genes in tumor and urine from 55 patients with bladder tumors or carcinoma in situ. Deletions were examined on extracted DNA from tumors and urine sediments by the use of microsatellite markers located as close to the genes as possible. Fifty-five patients and 10 controls were included. We found no strict correlation between allelic deletions in bladder tumors and urine sediments from the same patient. Allelic deletions in urine sediments were at least as common in patients with carcinoma in situ and no bladder tumor (32%) as in patients with bladder tumors (20%). It was possible to identify allelic deletions in urine sediment from 1 patient with cystitis and no history of malignant bladder disease (6%). In conclusion we found no strict correlation between allelic deletions in bladder tumors and urine sediments. Allelic deletions in urine sediments seem to be at least as common in patients with carcinoma in situ as in patients with bladder tumors.     

Indolo[3,2-b]carbazole inhibits gap junctional intercellular communication in rat primary hepatocytes and acts as a potential tumor promoter

Indole-3-carbinol (I3C) is a naturally occurring substance that shows anti-carcinogenic properties in animal models. Besides its clear anti-carcinogenic effects, some studies indicate that I3C may sometimes act as a tumor promoter. Indolo[3,2-b]carbazole (ICZ), which is formed in the acidic environment of the stomach after intake of I3C, has a similar structure to, and shares biological effects with, the well-known tumor promoter 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Therefore, we hypothesized that ICZ could be responsible for the potential tumor-promoting activity of I3C. The aim of the present study was to investigate the effect of ICZ on gap junctional intercellular communication (GJIC) in primary cultured rat hepatocytes co-cultured with the rat liver epithelial cell line WB-F344. Indolo[3,2-b]carbazole inhibited GJIC in the rat hepatocytes in a dose- and time-dependent manner. Significant inhibition was observed after 8 and 12 h of treatment with 1 and 0.1 micro M ICZ, respectively. Maximum GJIC inhibition (cell-cell communication only 5% of control values) was observed after 24-48 h of ICZ treatment. Continued exposure to 1 micro M ICZ suppressed GJIC until approximately 120 h. Both ICZ and TCDD treatment reduced the Cx32 mRNA level as well as the plasma membrane Cx32 staining. Indolo[3,2-b]carbazole increased the Cyp1a1, Cyp1a2 and Cyp1b1 mRNA levels concurrently with an increase in 7-ethoxyresorufin O-deethylase (EROD) activities. Maximum EROD activity and Cyp1a1 mRNA levels were observed after approximately 12 h, whereas Cyp1a2 and Cyp1b1 mRNA levels peaked after 48 h. This study shows that ICZ may possess tumor promoter activity down-regulating GJIC by mechanisms, which seem to include activation of the Ah receptor and/or Cyp1 activity. Further studies are needed in order to clarify the anticarcinogenic/carcinogenic effects of I3C and ICZ before high doses of I3C may be recommended as a dietary supplement.     

Deteriorating ischaemic stroke. cytokines,soluble cytokine receptors,ferritin, systemic blood pressure,body temperature,blood glucose,diabetes, stroke severity,and CT infarction-volume as predictors of deteriorating ischaemic stroke

The immune reactivity implicated in the pathogenesis of Guillain-Barré syndrome (GBS) and related diseases, which occur following infection with specific strains of Campylobacter jejuni bearing sialylated lipopolysaccharide structures that cross-react with specific gangliosides, is consistent with provocation of inflammation via molecular mimicry. In this review, we have focused upon microbial characteristics and structures, the fine structure of the essential carbohydrate determinants, and the application of our proposed criteria, modified from those of Koch for causation of infectious and of Witebsky for autoimmune diseases, to the circumstance of infectious induction of autoimmune disorder.     

Immunohistochemical study of the expression of cell cycle regulating proteins at different stages of bladder cancer

PURPOSE: The cell cycle is known to be deregulated in cancer. We therefore analyzed the expression of the cell cycle related proteins p21, p27, p16, Rb, and L-myc by immunohistochemical staining of bladder tumors. METHODS: The tissue material consisted of bladder tumors from three groups of patients; group 1, 23 patients with recurrent stage Ta (non-invasive) tumors; group 2, 22 patients presenting at their first admission with T2-4 (muscle invasive) tumors; group 3, 24 patients who experienced disease progression from Ta or T1 (invasive in connective tissue) to a higher stage. By immunohistochemical staining the protein expression was compared to allelic deletions of the corresponding genes. The allelic deletions were detected by PCR-based microsatellite analyses. RESULTS: We detected a significant reduction in the expression levels of the cell cycle related proteins p21(waf1) ( P=0.002), p27(kip1) ( P=0.03), Rb ( P=0.00002), and L-myc ( P=0.00000007) in muscle invasive tumors compared to noninvasive tumors. Tumors presenting as muscle invasive at first diagnosis had significantly lower levels of p16/CDKN2A ( P=0.01) when compared to muscle invasive tumors that followed Ta or T1 precursor lesions. We found no general correlation between allelic deletion of a gene and its immunohistochemical protein expression, indicating that the remaining allele may be capable of encoding a normal or even increased protein level. CONCLUSIONS: Our results support the hypothesis that bladder tumors with invasion at first diagnosis differ from those in which invasion follow superficial tumors. This difference is reflected as a different level in cell cycle related protein expression. The data also indicate that allelic deletions of cell cycle related genes do not correlate with an altered level of protein expression.     

Time trends in organ position and volume in patients receiving prostate three-dimensional conformal radiotherapy.

Using multiple computed tomography (CT) scans, 50 patients undergoing prostate radiotherapy were tested for clinically significant time trends in the target and surrounding critical structures. Significant trends were observed toward increasing bladder volume and increasing bowel-to-planning target volume separation; however, no trends were observed in the prostate, seminal vesicles, or rectum. The subset of patients undergoing hormone therapy was also tested and did not independently exhibit any significant time trends.     

Patient characteristics associated with differences in patients' evaluation of their general practitioner

Background  

Knowledge of the extent to which patient characteristics are systematically associated with variation in patient evaluations will enable us to adjust for differences between practice populations and thereby compare GPs. Whether this is appropriate depends on the purpose for which the patient evaluation was conducted. Associations between evaluations and patient characteristics may reflect gaps in the quality of care or may be due to inherent characteristics of the patients. This study aimed to determine such associations in a setting with a comprehensive list system and gate-keeping.