Biomedical subjects

Z Zhou

Publications and source records attributed to Z Zhou.

530 records · Page 30Linked to original sources

PubMedDate not supplied

Nuclear size, shape, and density in endometrial carcinoma: relationship to survival at over 5 years of follow-up. Does analyzing only cells occupying the G0-G1 peak add useful information?

OBJECTIVE: The authors, using image analysis, previously demonstrated nuclear size and summed optical density to be independent prognostic indicators of recurrence in patients with endometrial carcinoma. The same tumors were analyzed by studying the optical features in the G0-G1 peak to see if this changed the values found as well as their importance as prognostic features at greater than 5 years of follow-up. METHODS: Tumors from 74 consecutive patients, surgically treated, with endometrial cancer, were evaluated. Survival, depth of invasion, lymphvascular space invasion, FIGO stage, grade, histology were analyzed. DNA index, progesterone receptor status, as well as nuclear size (NUSZ), shape (NUSH), and summed optical density (NUSD) were evaluated. NUSZ, NUSH, and NUSD were quantified using image analysis. RESULTS: Fifteen patients died from disease during the observation period of the study. Mean follow-up was 82 months with a median of 84 months. Forty-nine patients had stage I cancers, five stage II, 17 stage III, and three stage IV. NUSZ and NUSD were all significantly different between the original (entire cell cycle) and the re-measured (G0G1 only) values (both P < 0.001). Multivariate analysis showed both the original (P = 0.0001) and G0G1-only (P = 0.046) NUSZ and the original (P = 0.0002) and G0G1-only (P = 0.018) NUSD to be independent prognosticators of survival. CONCLUSION: Image analysis is able to quantify cellular and nuclear parameters not otherwise quantifiable. NUSD and NUSZ correlated with traditional prognostic indicators, were demonstrated independent predictors of survival at over 5 years of follow-up. Although the re-measured NUSZ and NUSD from only the G0-G1 peak were significantly different from the original NUSZ and NUSD, they were not as valuable as prognostic factors. Nuclear size and summed optical density measured from the entire cell cycle are independent prognostic indicators of survival at greater than 5 years of follow-up. Measuring nuclear morphometric features in the G0-G1 peak only does not add any new prognostic information.

Adenocarcinoma, Clear Cell↗

PubMedDate not supplied

Protective effects of intermittent hypoxic adaptation on myocardium and its mechanisms.

Intermittent hypoxic adaptation offers as many beneficial effects in protecting against myocardial injuries as chronic continuous hypoxic adaptation. However, chronic continuous hypoxic adaptation readily causes some adverse effects on the organism, which may be prevented by intermittent hypoxic adaptation. As an approach to potentiate the protective effects, intermittent hypoxic adaptation is also much easier to apply to subjects who are not living at high altitude. The mechanisms underlying the cardioprotective effects of intermittent hypoxic adaptation are less understood, although great similarities exist between chronic continuous and intermittent hypoxic adaptation. The participation of several factors, such as myocardial vascularity, coronary blood flow, and cardiomyoglobin, which comprise the oxygen uptake system is not apparent, while the more efficient energetic metabolism after intermittent hypoxic adaptation may be a mechanism for cardioprotection. The possible roles of several signaling transduction pathways, including adrenoceptors, prostaglandins, and the adenosinergic system, in the beneficial effects of intermittent hypoxia are compared to those of chronic continuous hypoxic adaptation. Antioxidant enzymes and stress proteins may also be part of the mechanisms contributing to the cardioprotection of the intermittent hypoxic adaptation. As the cardioprotective effects of intermittent hypoxic adaptation employ multifold mechanisms, their clear elucidation needs more efforts.

Adaptation, Physiological↗

PubMedDate not supplied

Voltage-gated sodium channels in human aortic smooth muscle cells.

Whole-cell, voltage clamp methods were used to study inward currents in human aortic smooth muscle cells in culture. Cells were plated on glass coverslips, cultured in supplemented M-199 media with 5% serum and studied as primary cells and at passages 2-5. Inward currents were measured with a pipette solution containing Cs+ and TEA+ to block K+ currents and with 2.5 mM [Ca2+]0 in the perfusate. Inward currents activated at about -50 mV, peaked at about -15 mV and reversed at about +30 mV. Values of peak inward current averaged 14. 7 +/- 3.3 pA/pF and cell capacitance averaged 124 +/- 10 pF (n = 35). These currents activated rapidly with a time-to-peak current of 2.4 +/- 0.3 ms at a test potential of -10 mV from a holding potential of -80 mV. The current also inactivated rapidly with a time course that could be described by two components with time constants of 1.8 +/- 0.2 and 17.8 +/- 3.5 ms at -10 mV. The currents decreased when extracellular Na+ was reduced and were completely inhibited by 50 nM tetrodotoxin (TTX), suggesting that they represented voltage-gated Na+ currents (INa). Activation curves were characterized with a V0.5 = -16.6 +/- 2.4 mV and a slope factor k = -5.2 +/- 0.2 mV while inactivation curves were characterized with a V0.5 = -60.9 +/- 1.7 mV and a slope factor k = 8.8 +/- 0.4 mV. Lowering external [Ca2+] to zero increased the maximum INa, shifted its voltage dependence in the hyperpolarizing direction and increased the rate of INa inactivation. Increasing external [Ca2+] or [Mg2+]decreased INa and slowed its rate of inactivation. These studies demonstrate the presence of voltage-gated Na+ channels with high TTX sensitivity that are modulated by extracellular divalent cations in human aortic smooth muscle cells maintained in cell culture. Window currents were found in the voltage range of -50 to -20 mV, suggesting that these channels could contribute to the resting membrane potential.

Calcium↗

PubMedDate not supplied

p53 polymorphisms and haplotypes in nasopharyngeal cancer.

Three p53 DNA polymorphisms (BstUI and MspI RFLPs in exon 4 and intron 6, respectively, and a 16-bp duplication in intron 3) and their haplotype combinations were studied in 73 patients (61 males and 12 females) with nasopharyngeal cancer and 105 healthy controls from the Guizhou province in southern China. Increased frequencies of the 16-bp A2 allele (p = 0.005), MspI A1 allele (p = 0.021) and the BstUI A1 (Pro) allele (p = 0.072) were found among the patients, with more pronounced differences in male patients (p = 0.003, 0.014 and 0.052, respectively). Haplotype frequencies and linkage disequilibria differed from those in Caucasians. The differences between controls and patients, especially male patients, increased when the analysis was based on haplotypes. The lowest risk for nasopharyngeal cancer was associated with the haplotype 16-bp A1, BstUI A2, MspI A2 (1-2-2). A somewhat higher risk was observed in the 1-1-2 haplotype (replacing the Arg with a Pro allele). The highest risk was, however, found in the rare combinations including the 16-bp A2 and MspI A1 alleles with an odds ratio of 4.9 [95% confidence interval (CI) = 1.8-13.2] in all patients and 5.4 (95% CI = 2.0-14.8) in male patients. The haplotype associations found in this study differ from those found in previous cancer association studies in Caucasians. This together with the fact that the intronic markers conferred the highest risk figures suggest that the mechanism behind the observed associations is linkage disequilibrium and not direct functional involvement of the codon 72 alleles.

Alleles↗

PubMedDate not supplied

Multicenter evaluation of the performance and clinical utility in longitudinal monitoring of the Bayer Immuno 1 complexed PSA assay.

We conducted a multicenter evaluation of the analytical and clinical performance of the automated Bayer Immuno 1 complexed PSA (cPSA) assay, and compared assay performance to the Bayer Immuno 1 PSA assay. We sought to determine whether measurements of cPSA could be of clinical utility in the management of patients with prostate cancer. Results of the 10-day imprecision across three evaluation sites produced total CV < 2.50% and an analytical sensitivity of 0.02 microgram/L. There was an increased trend in clinical sensitivity for prostate cancer with increasing stage of disease (71-86%). Clinical specificity for patients with benign urogenital disease was 74.8%, and for other nonprostate diseases ranged from 91.1-100%. Retrospective serial monitoring of 155 patients with prostate cancer demonstrated concordance of cPSA measurements to clinical status for 97% of the patients analyzed. Results from the clinical studies using the Bayer Immuno 1 cPSA assay were comparable to results obtained with the Bayer Immuno 1 PSA assay. The Bayer Immuno 1 cPSA assay demonstrates analytical performance and clinical effectiveness in the management of prostate cancer patients during the course of disease and therapy.

Adolescent↗

PubMedDate not supplied

Will minority physician supply meet U.S. needs?

We project the future racial and ethnic composition of the U.S. physician workforce under different assumptions. Our projections show that reaching racial and ethnic population parity with a managed care-based requirement of 218 physicians per 100,000 population would require the number of first-year residents to roughly double for Hispanic and black physicians, triple for Native American physicians, and be reduced by about two-fifths for white physicians and two-thirds for physicians of Asian or Pacific Island origin.

Cultural Diversity↗

PubMedDate not supplied

Combined 21-hydroxylase and 11beta-hydroxylase deficiency: patient report and molecular basis.

A female newborn (46, XX) with ambiguous genitalia was initially diagnosed by biochemical criteria as having classical congenital adrenal hyperplasia caused by 11beta-hydroxylase deficiency. Shortly after effective treatment was administered, she developed a salt-wasting crisis with severe electrolyte imbalance. DNA analysis revealed a homozygous splice mutation in the second intron of the CYP21 gene, for which both parents were heterozygous. No mutations were found in the entire CYP11B1 gene, thus proving that the 11beta-hydroxylase deficiency was not caused by a gene mutation but rather was a secondary event, possibly due to androgen suppression of 11beta-hydroxylase activity.

Adrenal Hyperplasia, Congenital↗

PubMedDate not supplied

Effect of chronic ethanol consumption on activation of nitrosopyrrolidine to a mutagen by rat upper alimentary tract, lung, and hepatic tissue.

Tissues derived from male Sprague-Dawley rats which had been pair-fed isocaloric ethanol or carbohydrate control diets for 4 weeks were used to determine the effect of chronic ethanol exposure on the activation of the smoking and diet-associated procarcinogen nitrosopyrrolidine (NPY). Microsomal preparations from lungs and liver and S9 fractions from alimentary tract mucosa were tested for their capacity to activate NPY to a mutagen by the Ames Salmonella assay. Chronic ethanol exposure resulted in an increased capacity to activate NPY by microsomes derived from liver, lungs, and esophagus but not from stomach. The three tissues in which enhanced activation of NPY was observed in the present study also have been noted in epidemiological studies to be target sites of alcohol abuse-associated increased cancer risk. The results presented here suggest that dietary ethanol's effect on carcinogen metabolism may be responsible, at least in part, for the increased cancer risk observed in chronic alcohol abusers.

Alcoholism↗