Human auditory nerve compound action potentials and long latency responses

CONCLUSION: The compound action potential (CAP) is followed by a long latency response (LLR), attributable to the post-auricular musculature. The LLR to one pulse may overlap with the CAP to a subsequent one, contributing to the clinically observed reduction in CAP at high pulse rates. OBJECTIVES: To measure refractory and other influences on CAPs in humans and guinea pigs. MATERIALS AND METHODS: CAPs were obtained from humans using trans-tympanic and extra-tympanic electrocochleography and from anaesthetized guinea pigs. Stimuli were single pulses presented at a slow rate, pairs of pulses, and 100 ms pulse trains where the inter-pulse interval alternated between 4 and 6 ms. RESULTS: For single pulses, the CAP shape was similar across species. For pairs of pulses, the CAP to the second pulse was smaller than that to the first, and decreased with increasing inter-pulse interval in a way that was similar across species. For pulse trains, CAPs were observed in response to each pulse in the train for the guinea pigs, but not for humans. For both filtered and unfiltered single pulses, there was a large LLR in humans, but not in guinea pigs, with peaks at latencies of 10-12 and 20-25 ms. Posture affected the LLR in a way consistent with the post-auricular response.     

Mental health literacy survey of psychiatrically and generally trained nurses employed in a Singapore psychiatric hospital

Mental health literacy studies consider the capacity of respondents to recognize certain psychiatric disorders, judge the comparative utility of a range of interventions, and make estimates about outcome and prognostic issues. We report such a study involving a sample of nursing staff employed at a large psychiatric institution in Singapore, and who were provided with separate brief vignettes of mania, schizophrenia and depression. Subjects were highly accurate in 'diagnosing' schizophrenia, less accurate for depression and even less accurate in diagnosing mania. Depression was alternately diagnosed as stress, mania was most commonly misdiagnosed as schizophrenia, and for both psychotic conditions, a percentage returned non-psychotic diagnoses. In terms of treatment options, staff distinctly favoured a 'medical model' and viewed traditional and alternative healing options as distinctly harmful. Analyses contrasted psychiatrically trained and generally trained nurses, but identified few significant differences. Such information has the potential to shape the education and training of mental health professional staff, as well as provide important insights about how nurses may diagnose, view and favour alternative treatments and strategies to assist those with common psychiatric disorders.     

NRAMP1 and hGPX1 gene polymorphism and response to bacillus Calmette-Guérin therapy for bladder cancer

Background

The natural resistance-associated macrophage protein 1 (NRAMP1) gene is associated with susceptibility to Mycobacterium tuberculosis in humans and to bacillus Calmette-Guérin (BCG) in mice. The detoxification enzyme, human glutathione peroxidase 1 (hGPX1), is associated with recurrence of bladder cancer (BCa).

Objective

To determine whether NRAMP1 and hGPX1 gene polymorphisms correlate with response to BCG immunotherapy for non–muscle-invasive BCa (NMIBC).

Design, setting, and participants

DNA was obtained from the peripheral blood of 99 NMIBC patients who were prospectively randomized to receive postresection intravesical BCG (81 mg [n = 50] or 27 mg [n = 19]) or BCG (27 mg) with interferon alpha (IFN-α; n = 30). The median follow-up time was 60 mo.

Intervention

Intravesical BCG or BCG–IFN-α.

Measurements

Restriction fragment length polymorphism (RFLP) analysis was performed to identify polymorphisms in the NRAMP1 promoter region (GT repeat number) and at position 543 (aspartate [D] and/or asparagine [N] expression) within the NRAMP1 protein (D543N) and position 198 (proline and/or leucine expression) within the hGPX1 protein (Pro198Leu). Data were analyzed using χ² analysis, multivariate analysis, and Kaplan-Meier curves.

Results and limitations

On univariate analysis, the NRAMP1 D543N G:G genotype had decreased cancer-specific survival (CSS; p = 0.036). The hGPX1 CT genotype (Pro-Leu) had decreased recurrence time (p = 0.03) after BCG therapy. On multivariate analysis, patients with the NRAMP1 D543N G:G genotype and allele 3 (GT)n polymorphism had decreased recurrence time (p = 0.014 and p = 0.03) after BCG therapy. The limitation of this study was its small sample size.

Conclusions

Polymorphisms of the NRAMP1 and hGPX1 genes may be associated with recurrence of BCa after BCG immunotherapy.     

Chemopreventive Effect of Lactobacttlus rhamnosus on Growth of a Subcutaneously Implanted Bladder Cancer Cell Line in the Mouse

Lactic acid bacteria are known to have beneficial effects on the host, such as preventing carcinogenesis. The present study was designed to evaluate the chemopreventive effects of Lactobacttlus rhamnosus strain GG (LGG) in suppressing bladder cancer formation in a murine subcutaneous model of bladder cancer involving the inoculation of MB49 cells in C57B/L6 mice. After tumor implantation, one group of mice (n=8) was fed LGG immediately. The remaining mice that had tumors between 0.03–0.1 cm³ were divided into two groups: those fed LGG after 7 days (n=7) and those fed saline (n=7). A second group of mice without any inoculation of MB49 cells was fed either LGG (n=10) or saline (n=10) and served as non-tumor-bearing controls. LGG was administered orally at 1.6×l0⁸ colony-forming units daily. Mice fed LGG immediately after tumor cell implantation formed smaller tumors and some did not develop tumors (2 out of 8 mice), when the tumor burden was small. The level of spleen CD3, CD4 and CD8a T lymphocytes, as well as natural killer cells in mice fed immediately with LGG was also higher than that in control tumor-bearing mice. There was an increase in lymphocytes and granulocytes in tumor sections, especially from the immediately fed group as compared to the controls. Our results suggest that oral consumption of LGG may prevent tumor growth via modulation of the immune system. The potential of LGG as an adjunct therapy in the treatment of bladder cancer could be further explored.     

Internalization of Mycobacterium bovis, Bacillus Calmette Guerin, by bladder cancer cells is cytotoxic

Instillation of Bacillus Calmette Guerin (BCG) into the bladder is the standard treatment for superficial bladder cancer. It leads to a local inflammatory response due to the release of cytokines and influx of immune cells to the tumor site. Although the presence of an intact immune system is an essential criterion for successful therapy, attachment of the bacteria to the bladder urothelial is just as important. The purpose of our study is to determine the role of bacterial internalization by epithelial cells. Transfection of the alpha5 integrin gene into the BCG unresponsive bladder cancer cell line, RT4, caused an increase in bacterial uptake and also increased cell death. Treatment of cells with cycloheximide did not prevent bacterial internalization but blocked its cytotoxic effect suggesting that unlike cell death, the process of bacterial internalization does not require new protein synthesis. Our data also show that the bacteria secretory products can prevent its own internalization. The extract prepared from lyophilized BCG altered the phosphorylation status of the focal adhesion kinase which is responsible for cellular endocytosis. Therefore, bacterial phosphatases may be present in the bacterial extract. Their activity may inhibit BCG internalization. Thus washing the reconstituted bacteria to remove the enzymes before instillation into the bladder might improve the therapeutic outcome of intravesical BCG therapy.