Type D retrovirus markers in healthy Africans from Guinea

Sixteen matching sera and DNA samples from healthy African blood donors living in rural areas of Guinea were analysed for the presence of type D retrovirus markers. Screening for the antibodies against structural proteins of Mason-Pfizer monkey virus (M-PMV) was carried out by Western blot with a purified M-PMV as an antigen. Eight out of 16 sera samples were found to contain antibodies against at least two gag gene-coded proteins, and three of these were weakly positive against env gene-coded protein. Using PCR amplification and Southern hybridization, we detected M-PMV-like gag sequences in 11 out of 16 samples and env-related sequences in 8 out of 16 samples. Six DNAs were found to contain both M-PMV gag- and env-related sequences. Restriction endonuclease analysis of the PCR-amplified gag sequences from two individuals and direct DNA sequencing analysis of the amplimers confirmed their M-PMV-like origin. Detection of antibodies and M-PMV-related sequences in blood donors from Guinea, but not in French or Algerian blood donors, indicated exogenous SRV infection in humans from certain geographic areas of Western Africa.     

Construction and stratification of the stability domains of the linear dynamic systems with PID controllers

The regularities of motion of a point on the plane (in the space) of adjustable controller parameters at variations of the phase margin under a fixed crossover frequency were analyzed. The problem of decomposition of the stability domain into the zones with simple and complex Nyquist plots and subsequent construction of the point subset where all points satisfying the requirements on the system frequency characteristics was solved. Examples were presented.     

Central adiposity and hemodynamic functioning at rest and during stress in adolescents

OBJECTIVE: To examine the impact of central adiposity upon hemodynamic functioning at rest and during stress in adolescents. DESIGN: Cross-sectional, correlational study. SUBJECTS: 46 White and 49 Black normotensive adolescents with family histories of essential hypertension. MEASUREMENTS: Systolic and diastolic blood pressure (SBP, DBP), cardiac output and total peripheral resistance responses were assessed at rest, during postural change, video game challenge and forehead cold stimulation. Specific lower and higher waist-to-hip ratio (WHR) tertiles were created for each gender and then integrated for analyses. This resulted in a lower WHR tertile of 11 Whites and 21 Blacks and an upper WHR tertile of 15 Whites and 17 Blacks. RESULTS: No differences in age, gender or ethnicity proportions were found between tertile groups (all P > 0.21). The upper WHR group showed greater body weight, waist and hip circumferences, body mass index (BMI), triceps skinfold and body surface area (all P < 0.001). Controlling for peripheral (that is, triceps skinfold) and overall (that is, BMI) adiposity, the upper WHR group exhibited greater SBP (that is, peak response minus mean pre-stressor level) to all three stressors and greater DBP reactivity to postural change and cold pressor (all P < 0.05). CONCLUSION: Central adiposity appears to adversely influence hemodynamic functioning during adolescence. Underlying mechanisms responsible for these associations require exploration.     

Allelotype analysis of uterine leiomyoma: localization of a potential tumor suppressor gene to a 4-cM region of chromosome 7q

The degree and nature of patient involvement in consultations with health professionals influences problem and needs recognition and management, and public accountability. This paper suggests a framework for understanding the scope for patient involvement in such consultations. Patients are defined as co-producers of formal health services, whose potential for involvement in consultations depends on their personal rights, responsibilities and preferences. Patients' rights in consultations are poorly defined and, in the National Health Service (NHS), not legally enforceable. The responsibilities of patients are also undefined. I suggest that these are not to deny, of their own volition, the rights of others, which in consultations necessitate mutuality of involvement through information-exchange and shared decision-making. Preferences should be met insofar as they do not militate against responsibilities and rights.     

Dysregulated cyclin D1 expression early in head and neck tumorigenesis: in vivo evidence for an association with subsequent gene amplification

Cyclin D1 proto-oncogene is a key regulator of the mammalian cell-cycle acting at the restriction point in late G1. Amplification of the cyclin D1 locus, located on chromosome 11q13, as well as cyclin D1 protein overexpression have been reported in several human malignancies. The purpose of this study was to evaluate cyclin D1 gene copy status and protein expression during the multistep process of head and neck tumorigenesis, using a combination of fluorescence in situ hybridization and immunohistochemistry techniques. From 29 selected patients presenting with head and neck squamous carcinoma and whose tumor cytospins had been previously screened for presence (16 cases) or absence (13 cases) of amplification at the 11q13 band, we analysed 46 paraffin-embedded tissue specimens that demonstrated, besides the primary tumor, the presence of contiguous adjacent normal tissue and/or premalignant lesions. Of the 16 amplified cases, nine demonstrated a continuous progression from premalignant to invasive carcinoma and seven (77.7%) of these cases showed cyclin D1 gene amplification in premalignant lesions prior to development of invasive carcinoma. Increased cyclin D1 protein expression was observed in all 16 amplified tumors and five of the 13 (38.4%) non-amplified tumors. Interestingly, dysregulated cyclin D1 expression was also found in the premalignant lesions adjacent to all 16 amplified tumors, and it appeared to precede cyclin D1 gene amplification. In contrast no dysregulated expression was detected in the premalignant lesions of the non-amplified tumors. In conclusion, these findings provide strong evidence for early dysregulation of cyclin D1 expression during the tumorigenesis process and suggest that dysregulated increased expression precedes and possibly enables gene amplification.     

Rapid, sensitive procedure to determine buspirone levels in rat brains using gas chromatography with nitrogen-phosphorus detection

Reported here is a rapid, sensitive and relatively inexpensive procedure using gas chromatography with nitrogen-phosphorus detection (GC-NPD) to quantify buspirone levels in brains of rats. The analyte was directly extracted from brain homogenate with toluene after basification and then subjected to GC-NPD analysis using a capillary column. The calibration curves were linear over the range of 10 to 320 ng per 2 ml of brain homogenate, with typical r2 values >0.99. The assay was highly reproducible and gave peaks with excellent chromatographic properties.