Genetic deletions of glutathione-S-transferase as a risk factor in squamous cell carcinoma of the larynx: a preliminary report

PURPOSE: To test whether genetic deletions of glutathione-S-transferase (GST) are associated with squamous cell carcinoma (SCC) of the larynx. GST are a group of detoxifying enzymes that may help reduce the risk of developing cancer in response to environmental carcinogens. Polycyclic aromatic hydrocarbons, found in high concentration in cigarette smoke, are known carcinogens especially for SCC of the larynx. Individuals with absolute or relative deficiency of the GST enzyme system may therefore be at a higher risk of developing laryngeal carcinoma. MATERIALS AND METHODS: Genotyping for GST-M1 and GST-T1 was performed using polymerase chain reaction (PCR) assay on fresh frozen tissue specimens of 20 patients with SCC of the larynx and on 20 control subjects with a similar smoking history. Because this assay results in the absence of a PCR product in individuals expressing the GST-M1/GST-T1 null genotype, oligonucleotide primers that amplify a portion of the albumin gene were included in a multiplex PCR as a positive control for DNA quality and PCR conditions. The chi-square test was used for statistical analysis. RESULTS: GST-M1 gene was deleted in 80% of patients with laryngeal SCC and in 50% of control subjects (P <.05). No statistically significant difference was observed in the incidence of GST-T1 gene deletion in patients with SCC of the larynx and control subjects. CONCLUSION: GST-M1 gene deletion was significantly associated with SCC of the larynx and may produce a risk for this particular disease.     

Hypertension in black people: study of specific genotypes and phenotypes will provide a greater understanding of interindividual and interethnic variability in blood pressure regulation than studies based on race

Hypertension is more frequent and more severe in some Black populations. Although many studies have focused on hypertension in black people in an attempt to understand the genetic and environmental factors that regulate blood pressure, this approach has not been productive. Study of the relationship between specific phenotypes and genotypes, both within and across ethnic groups, is more likely to advance our understanding of the regulation of blood pressure than studies focused on race and blood pressure.     

Effects of light intensity, n-alcohols, water-soluble colorants, and solution viscosity on photoisomerization of sorivudine

Effects of various factors, such as light intensity, polarizability of n-alcohol solvents, addition of colorants, and viscosity of solutions on the kinetics of the photoisomerization of therapeutically effective E-isomer of sorivudine to its less effective Z-isomer were studied. Solutions of known concentrations of E-isomer or Z-isomer in water or in a series of n-alcohols were directly exposed to ultraviolet (UV) A light, or visible light of 400 or 900 foot candles (fc). E-isomer solutions containing various colorants at 1% w/v, or in a series of poloxamer solutions of different viscosities, were also exposed to 400 or 900 fc light. Using the stability-indicating HPLC assay, which showed mass-balance between the starting isomer and the converting isomer, the kinetics of photoisomerization were monitored. The photoisomerization reaction, which takes place on the vinyl side chain, was found to be a first-order reversible reaction. In water, the rate of conversion of E-isomer to Z-isomer was faster than that of Z-isomer to E-isomer, since, E-isomer with higher extinction coefficient absorbed substantially more light than Z-isomer. The rate of photoisomerization increased with the intensity of the visible light and was very rapid in the presence of UV A light (300 to 400 nm), which is to be expected based on the 239 nm and 283 nm absorption maxima of sorivudine. Addition of water-soluble colorants retarded the photoisomerization process significantly, especially as the maximum absorption wavelengths (lambda max) of the colorants approached the UV region. The rate of photoisomerization increased with increasing polarizability (alpha s) of the n-alcohol solvents. Polarizable solvents such as alcohols could compensate for the electron density built up in the excited state, and thus facilitated the photoisomerization process. The rate of photoisomerization decreased as the viscosity of solution increased. This may be attributed to the fact that the twisting of the C=C bond in the excited state can be inhibited by the friction imposed by the viscous medium.     

Osteochondral lesions of the capitellum in pediatric patients: role of magnetic resonance imaging

The role of magnetic resonance imaging (MRI) in the evaluation of patients with osteochondral lesions of the capitellum is undefined. To define its role, the cases of nine consecutive children with 11 capitellar osteochondral lesions who underwent MRI were reviewed. Magnetic resonance imaging accurately delineated the size of the osteochondral lesions and identified capitellar loose bodies not seen on plain radiographs in two elbows. In patients without capitellar loose bodies, two distinct MRI patterns existed that were similar to those seen in femoral head osteonecrosis. Magnetic resonance imaging aided in the treatment of children with osteochondral lesions of the capitellum. Further studies are necessary to define the significance of the two MRI patterns.     

Cardiac troponins have no prognostic value for acute and chronic cardiac events in asymptomatic patients with end-stage renal failure

BACKGROUND: Cardiovascular diseases determine overall mortality in patients with end-stage renal failure. Therefore, testing for myocardial ischemia is important. Elevation of cardio-specific troponins have been frequently measured in patients with end-stage renal failure. Thus, we studied systematically whether patients on chronic intermittent hemodialysis without overt coronary heart disease have increased serum levels of cardiac troponin T and cardiac troponin I. After 2 years, the patients were screened again for cardiac events. METHODS AND RESULTS: The patients had no history of angina during the previous 3 months or myocardial infarction (MI) within the previous 2 years. For analysis we used two cardio-specific assays for troponin T as well as for troponin I and compared the results with the CK-MB concentration. In a number of patients serum concentrations were elevated above the reference range as follows: troponin T rapid bedside assay: 41 of 100 patients, troponin I rapid bedside assay: 27 of 100 patients, quantitative measurement oftroponin T: 22 of 100 patients, quantitative measurement oftroponin I: 7 of 100 patients, CK-MB: 2 of 100 patients. The increased serum levels of cardiac troponins were neither the result of uremic perimyocarditis (pericardial effusion), changes in the hemodialysis regimen, pulmonary congestion nor were they consistent with the etiology of renal failure. None of the patients with an elevated troponin level in either of the test suffered from any acute cardiac event initially. Within 2 years 18 of 100 patients died, 13 out of them because of cardiac events. Fourteen patients had a myocardial infarction and 19 patients developed angina pectoris. Sensitivity and specificity (0.75 and 0.67) of troponin T rapid bedside assay for MACE (angina pectoris, MI, cardiac death) was lower compared to studies in patients with normal renal function. Correlation between troponin elevation and late outcome was low or absent. CONCLUSION: Patients on chronic intermittent hemodialysis frequently present with elevated TnT and TnI levels which cannot be used as predictors of acute and chronic cardiac events. Rapid bedside assays have a lower specificity than quantitative assays.     

Social phobia: prevalence and diagnostic threshold

This article reviews the literature on the prevalence and demographic features of social phobia in both community and general medical settings. The age at onset of social phobia is examined, as are comorbid conditions. Important differences between social phobia as it appears in the community and in primary care settings are explored. We conclude that social phobia is common and associated with significant impairment in a number of life areas. We discuss the diagnostic threshold of social phobia and potential difficulties in differentiating this disorder from other mental disorders.     

Topographic restriction of TAG-1 expression in the developing retinotectal pathway and target dependent reexpression during axon regeneration

TAG-1, a glycosylphosphatidyl inositol (GPI)-anchored protein of the immunoglobulin (Ig) superfamily, exhibits an unusual spatiotemporal expression pattern in the fish visual pathway. Using in situ hybridization and new antibodies (Abs) against fish TAG-1 we show that TAG-1 mRNA and anti-TAG-1 staining is restricted to nasal retinal ganglion cells (RGCs) in 24- to 72-h-old zebrafish embryos and in the adult, continuously growing goldfish retina. Anti-TAG-1 Abs selectively label nasal RGC axons in the nerve, optic tract, and tectum. Axotomized RGCs reexpress TAG-1, which occurs as late as 12 days after optic nerve lesion, when regenerating RGC axons arrive in the tectum, suggesting TAG-1 reexpression is target contact-dependent. Accordingly, TAG-1 reexpression ceases upon interruption of the regenerating projection by a second lesion. The topographic restriction of TAG-1 expression and its target dependency during regeneration suggests that TAG-1 might play a role in the retinotopic organization and restoration of the retinotectal pathway.     

Satisfaction of inpatients and outpatients with staff, environment, and other patients

The study described here compared levels of satisfaction with staff, environment, and other patients among 420 first-time and long-term patients in psychiatric outpatient and inpatient settings. The demographic, clinical, and outcome variables associated with satisfaction were explored. Patient satisfaction was related to quality of life, social functioning, treatment expectations, and one-year psychological and physical prognoses. Perceptions of other patients were significantly more positive among long-term patients than among first-time patients. The concerns of first-time patients about other patients are of special importance, and they should be addressed during initial treatment.     

History of Chinese stereotactic and functional neurosurgery

Chinese stereotactic and functional neurosurgery started in 1963. Dr. Jian-Ping Xu did stereotactic surgery for Parkinson's disease with a small Cartesian coordinate stereotactic device which he designed. In 1983, the first Chinese Institute of Stereotactic and Functional Neurosurgery was established by Dr. Jian-Ping Xu and Dr. Ye-Han Wang in the Anhui Provincial Hospital in the city of Hefei. Since then, the Institute has hosted an annual National Workshop on Stereotactic and Functional Neurosurgery, where more than 80% of the functional neurosurgeons now practicing in China have been trained. In 1986, the Chinese Society of Stereotactic and Functional Neurosurgery was established, and the first issue of the Chinese Journal of Stereotactic and Functional Neurosurgery was published. With more than 35 years of development, stereotactic and functional neurosurgery has become a very important branch of surgery in China. More than 5,000 functional neurosurgery procedures and more than 8,000 stereotactic radiosurgery procedures are now performed annually.