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Biomedical subjects

G W Jones

Publications and source records attributed to G W Jones.

At least 37 records · Page 2Linked to original sources
PubMed1997

Population dynamics and their impact on adolescents in the ESCAP region.

"This study examines the impact on adolescents of the dramatic demographic, social and economic changes currently taking place in the ESCAP region. Among the aspects it considers are the growth of the adolescent population, their age at marriage and fertility, educational developments, labour force participation, and the effects of poverty, globalization and urbanization on this segment of the population. It concludes by drawing out the implications of the research for policy and programme purposes."

Adolescent↗
PubMed1996

Multiple phase variation in haemolytic, adhesive and antigenic properties of Streptococcus gordonii.

Streptococcus gordonii gave rise to beta-haemolytic variants (Bhp+ for beta-haemolysin production) at frequencies of 10(-4)-10(-3) on agar medium containing washed horse erythrocytes. Bhp+ variants reverted to the wild-type alpha-haemolytic phenotype (Bhp-) at the same frequencies. There was a significant probability (> or = 0.1) that phase variation in Bhp and phase variation in the previously described Spp (sucrose promoted phenotype) would occur concomitantly, but there was no correlation between these phenotypes. There was evidence also of independent phase variation in adhesion to saliva-coated hydroxyapatite (Asp for adhesion to salivary pellicles), in lactose-sensitive coaggregation (Cls for coaggregation, lactose-sensitive) and in the concentrations of particular cell surface antigens (Cap for cell antigen profile) in strains that had undergone phase changes in Spp and/or Bhp. Phase variation in all these phenotypes were transitions between high and low levels of activity and each appeared to occur as an independent event. Significant associations (P << 0.0001 by contingency table analysis) between particular phenotypes such as Bhp and Asp and between Asp, Cls and Cap phenotypes, however, were apparent. The results suggest that S. gordonii cells become predisposed to phase variation and that the resulting independent phenotypic changes may give rise to phenotypically diverse streptococcal populations able to accommodate rapid and transient environmental changes in the mouth.

Antigens, Bacterial↗
PubMed1995

Sucrose-dependent accumulation of oral streptococci and their adhesion-defective mutants on saliva-coated hydroxyapatite.

The adhesion and accumulation of oral streptococci on saliva-coated hydroxyapatite was examined in strains representing species that appear in initial plaque (Streptococcus sanguise FC1 and Streptococcus oralis C5) and in more mature plaque (Streptococcus gordonii G9B). Washed cells of strains FC1 and C5 did not attach better to saliva-coated hydroxyapatite than did strain G9B, suggesting that the degree of initial adhesiveness does not alone account for the temporal appearance of these bacteria in dental plaque. Growing cells of each strain were also examined for their ability to accumulate on saliva-coated hydroxyapatite. The addition of sucrose to the medium promoted the accumulation of strain G9B more than it promoted the accumulation of strains FC1 and C5. Sucrose also enhanced the accumulation of adhesion-defective mutants of each strain to levels similar to those of the respective parent strains. These results suggest that sucrose-dependent accumulation may facilitate the colonization of the tooth surface by these species of oral streptococci when adhesion is limited by reduced bacterial adhesiveness or limited pellicle-binding sites.

Bacterial Adhesion↗
PubMed1995

Patterns of care for carcinoma of the prostate gland: results of a national survey of 1984 and 1990.

BACKGROUND: The annual incidence of carcinoma of the prostate gland increased from an estimated 76,000 cases in 1984 to 200,000 in 1994. Part of this increase may be the result of increased detection. Management of the disease has also changed. To measure such changes, the American College of Surgeons conducted a patient care evaluation study of carcinoma of the prostate gland. STUDY DESIGN: Information was voluntarily submitted by cancer registrars on forms designed by a team of specialists. Data were received from 730 hospitals (of 2,000 hospitals invited for the study) on 14,716 patients with newly diagnosed adenocarcinomas of the prostate gland in 1984 and from 1,035 hospitals for 23,214 patients with carcinoma of the prostate gland in 1990. RESULTS: From 1984 to 1990, there was increased diagnostic use of the prostate specific antigen (PSA) test (from 5.1 to 66.4 percent of incident carcinomas) and transrectal ultrasound (TRUS) (0.9 to 19.7 percent). Use of the prostatic acid phosphatase assay declined from 62.4 to 47 percent. Although the proportion of early stage (0, I, II) disease increased for all racial or ethnic groups combined, the greatest increase was for whites (from 57.3 to 60.6 percent), while the increase for African-Americans was less (from 46.9 to 48.3 percent). The use of radical prostatectomy without radiation therapy or chemotherapy increased from 7.3 to 20.3 percent and the proportion of patients receiving no carcinoma-directed treatment decreased from 37.8 to 30 percent. Radiation therapy remained the same. Hormone therapy without radical prostatectomy declined from 24.4 to 19.7 percent. African-Americans had a lower five-year survival rate than whites, even when stratified for stage. CONCLUSIONS: The diagnostic use of the PSA test and TRUS increased markedly by 1990 and may have contributed to the increased diagnosis of carcinomas of the prostate gland and the earlier stage at diagnosis. The overall use of radical prostatectomy has increased and the proportion of patients receiving no treatment has decreased. African-Americans had a lower five-year survival rate than other groups, even when stage was controlled.

Acid Phosphatase↗
PubMed1995

Electron beam treatment for cutaneous T-cell lymphoma.

Total skin electron radiation has proven efficacy in treating MF. It is a complex technique that requires a dedicated radiation team, involving physicists, radiotherapists, and radiation oncologists. A center must treat a sufficiently high volume of patients to justify the development of TSE, with appropriate organization, time, and expense. The radiation team should be an integral part of a multidisciplinary clinical group, including medical oncologists, dermatologists, pathologists, and nurses. In these contexts, TSE has appropriately been developed in a limited number of centers. Cooperation between these centers is essential for further refinement of TSE techniques and for evolution of the role of TSE in the management of most patients with MF.

Combined Modality Therapy↗
PubMed1994

Prognosis with newly diagnosed mycosis fungoides after total skin electron radiation of 30 or 35 GY.

PURPOSE: To determine the prognosis of new patients with T1-4N0-1B0M0 mycosis fungoides treated with total skin electron beam radiation. METHODS AND MATERIALS: 25 consecutive patients received 30 Gy with 3 or 4 MeV electrons in 1977-1980; 121 received 35 Gy with 4 MeV in 1980-1992. Response rates, relapse-free survival, and overall and cause-specific survivals were assessed by explicit criteria. The relationships of T, N, gender, age, and radiation technique to prognosis were investigated by regression statistics. RESULTS: The average age was 55 years and the male:female ratio was 1:4. Forty-four percent were T1N0 and 34% were T2N0. The overall complete response rate was 82%, and lower T status, more radiation, and female gender were independently and positively associated with response. Median follow-up was 5.2 years. T1 patients who entered remission had a higher relapse-free survival compared to T2 through T4 patients. Thirty-four percent of T1 patients remained relapse-free at 6 years, compared to fewer than 20% of T2-4 patients. For all 146 patients the median overall survival was not reached at 15 years. Only 8 of 29 deaths were related to mycosis fungoides and these were significantly associated with higher T. The 54 T1N0 patients who had 35 Gy had a 10-year mycosis fungoides-specific survival of 100%. CONCLUSION: Total skin electron beam radiation gives good results with T1N0B0M0 disease. T3-4 disease is less likely to respond, it relapses more quickly, and it implies a poorer survival, but radiation offers palliation. T2 responds like T1, but relapses like T3-4. T2 also implies an intermediate survival. These results have implications for staging, informed consent, optimizing radiation treatment, and clinical trials.

Female↗
PubMed1994

Results of conservative management of clinically localized prostate cancer.

BACKGROUND: The selection of treatment for patients with localized prostate cancer requires reliable information about the outcome of conservative management. Previous studies of this question are generally considered unreliable because they were uncontrolled and nonrandomized. METHODS: We performed a pooled analysis of 828 case records from six nonrandomized studies, published since 1985, of men treated conservatively (with observation and delayed hormone therapy but no radical surgery or irradiation) for clinically localized prostate cancer. A Cox regression analysis was performed to determine which factors influenced survival among patients who did not die of causes other than prostate cancer (disease-specific survival). Kaplan-Meier curves for overall and metastasis-free survival among such patients were compared with use of the log-rank method and the Mantel-Haenszel test. RESULTS: Factors that had a significant effect on disease-specific survival were grade 3 tumors (risk ratio, 10.04), residence in Israel (risk ratio, 2.48) or New York (risk ratio, 0.37), and age under 61 years (risk ratio, 0.32). Ten years after diagnosis, disease-specific survival (with data on men who died from causes other than prostate cancer censored) was 87 percent for men with grade 1 or 2 tumors and 34 percent for those with grade 3 tumors; metastasis-free survival among men who had not died of other causes was 81 percent for grade 1, 58 percent for grade 2, and 26 percent for grade 3 disease. These findings were not affected by the inclusion of men who had early-stage cancer, were older, had worse-than-average health, or underwent delayed radiation therapy or radical prostatectomy. CONCLUSIONS: The strategy of initial conservative management and delayed hormone therapy is a reasonable choice for some men with grade 1 or 2 clinically localized prostate cancer, particularly for those who have an average life expectancy of 10 years or less. New treatment strategies are needed for men with grade 3 prostate cancer.

Aged↗
PubMed1994

Enzymatic measurement of phosphatidylglycerol in amniotic fluid.

We describe an enzymatic method for measuring phosphatidylglycerol (PG) at concentrations as low as 0.2 mumol/L in amniotic fluid. Amniotic fluid (1.5 mL) is centrifuged at 10,000g for 20 min to obtain a lamellar body pellet, which is reconstituted with 0.5 mL of buffer. The PG is measured by a two-step enzymatic scheme. Recovery studies demonstrated that the pellet contains > 97% of the PG present in amniotic fluid. Between-run CVs were 28%, 5.7%, and 2.6% for amniotic fluid controls with means of 0.32, 3.9, and 10.7 mumol/L, respectively (n = 20). The enzymatic procedure was not significantly affected by blood, meconium, bilirubin, or other phospholipids. Lecithin/sphingomyelin ratio (n = 101) and fluorescence polarization (n = 127) compared with log(PG) showed correlation coefficients of 0.832 and -0.866, respectively. This test's ability to detect low concentrations of PG in amniotic fluid may make it a better predictor of fetal lung immaturity than previous methods.

Amniotic Fluid↗
PubMed1993

Prostate cancer. Magnitude of the problem. American College of Surgeons database and epidemiologic study.

BACKGROUND: The third American College of Surgeons pattern of care survey for cancer of the prostate is underway to document the current methods and means of presentation, diagnosis, and clinical management of patients in the United States. METHODS: Questions about the geographic distribution and methods of treatment by stage and grade together with patient mix and survival information will be answered from the data collected from more than 950 hospitals across the United States for the period 1984-1990. May 1992 was the final date for submission of data for this survey. CONCLUSIONS: Prostate cancer continues to be the most common cancer in men, excluding skin cancer. The annual number of patients with this disease reported in the National Cancer Database for 1988 was 26,957, an increase of 9427 cases yearly since the end of the second American College of Surgeons' survey in 1983.

Age Factors↗
PubMed1993

Is demographic uniformity inevitable?

"Globalizing processes of industrialization and Westernization are creating a retreat from diversity in human experience. The paper discusses whether population trends are reinforcing this process and draws on findings about growth rates, the family and urbanization in Western countries, East and Southeast Asia and Latin America. The extent to which counterbalancing forces, including cultural resilience, are curbing homogenization is also examined."

Cross-Cultural Comparison↗
PubMed1993

Growth and phenotypic characterization of Legionella species on semisolid media made with washed agar.

Legionella pneumophila (and 28 Legionella species) grew efficiently on charcoal-free, buffered yeast extract medium made with washed agar and without apparent loss of infectivity for U937 cells. Because charcoal-free, buffered yeast extract is transparent, it is a suitable base for indicator media and pigment detection. In standard media, charcoal apparently prevents agar contaminants from inhibiting Legionella growth.

Agar↗