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Biomedical subjects

P Rhodes

Publications and source records attributed to P Rhodes.

At least 37 records · Page 2Linked to original sources
PubMed1996

Four outbreaks of Salmonella enteritidis phage type 4 food poisoning linked to a single baker.

An outbreak of gastrointestinal illness occurred among a party of diners at a hotel in South Yorkshire. A case control study identified a gateau, from an outside supplier, as the likeliest vehicle of infection. Further gateaux from the same baker's premises and other outlets were examined microbiologically. Three other outbreaks of food poisoning in neighbouring districts were recognised and found to be associated with gateaux supplied by the same baker. A total of 32 cases were identified. Stool specimens from 24 cases grew Salmonella enteritidis phage type (PT) 4. The same organism was also grown from gateau in the domestic refrigerator of the chef of one hotel, cheesecake made by the same baker, and a gateau and ingredients from the baker's premises. The isolates of S. enteritidis PT4 were all fully sensitive to antibiotics, and had the same plasmid and pulsed field gel electrophoresis profiles. It is most likely that cross contamination occurred from infected raw eggs on the baker's premises. The control measures instituted probably prevented two further outbreaks, and the baker now uses only pasteurised eggs. The benefits of close cooperation between different local and health authority districts in the investigation of the outbreaks are discussed.

Disease Outbreaks↗
PubMed1996

C-type natriuretic peptide.

C-type natriuretic peptide is a 22-amino acid peptide that was initially identified in the central nervous system. The distribution of C-type natriuretic peptide, which has structural homology with atrial and brain natriuretic peptides, is wide and includes the endothelium, myocardium, gastrointestinal, and genitourinary tracts. The biological effects of this peptide are being elucidated in a number of sites in a number of species; however, the novel endothelial site of production of C-type natriuretic peptide and the proximal situation of its receptor in vascular smooth muscle suggest that this vascular natriuretic peptide system may play a role in concert with other local systems in the control of vascular tone.

Animals↗
PubMed1996

Arginine, lysine and ornithine as vasodilators in the forearm of man.

Nitric oxide is an endogenous vasodilator produced from L-arginine and oxygen by stereospecific enzymes. L-arginine itself can act as a vasodilator when administered at high doses to humans. This effect has been attributed by some to provision of extra substrate for production of nitric oxide. This work compares L-arginine-induced vasodilation with that caused by D-arginine, hyperosmolar sodium chloride and by other cationic amino acids in the resting forearm vasculature of normal subjects. By these means we identify whether L-arginine-induced vasodilation has a component related to stereospecific provision of substrate for nitric oxide production, or whether it can be accounted for by other phenomena. Effects of hyperosmolar sodium chloride and both L and D isomers of arginine, lysine and ornithine on forearm blood flow in eight normal male subjects were compared by bilateral forearm venous occlusion plethysmography. Vasodilator responses to saline and each amino acid were compared as the area under dose-response curves with single-factor analysis of variance (ANOVA). The magnitude of vasodilation obtained with the D isomers of each amino acid was compared with the L counterpart by application of single-factor ANOVA to the appropriate areas under dose-response curves. All three cationic amino acids increased forearm blood flow. Part of the increase could be related to the high osmolality of infusates-comparison with equiosmolar sodium chloride solutions shows that ornithine does not differ significantly as a vasodilator (P > 0.4), but that arginine and lysine have greater vasodilator effects than can be accounted for by osmolality alone (P < 0.001). The D isomers of arginine and lysine were more potent dilators than their L counterparts (arginine P < 0.03, lysine P < 0.02). The vasodilator effects of arginine in the forearm vascular bed at rest are not stereospecific, they are common to other cationic amino acids, greater for D isomers and occur only when normal plasma concentrations are raised far above the physiological range. These features suggest that the vasodilator effect of arginine is in part physical and related to the presence of the molecule in the vessel lumen. They do not suggest that increased provision of substrate, with a consequence of increased nitric oxide production, is the principal basis of L-arginine-induced vasodilation in normal humans.

Adolescent↗
PubMed1996

Changing levels of measles antibody titers in women and children in the United States: impact on response to vaccination. Kaiser Permanente Measles Vaccine Trial Team.

OBJECTIVES: In the United States, younger women are more likely to have immunity to measles from vaccination and are less likely to have been exposed to the wild virus than are older women. To evaluate changes in measles antibody titers in women in the United States and children's responses to measles vaccination, we analyzed data from a measles vaccine trial. METHODS: Sera collected from children before vaccination at 6, 9, or 12 months of age and from their mothers were assayed for measles antibodies by plaque reduction neutralization. Responses to vaccination with Merck Sharp & Dohme live measles virus vaccines at 9 months (Attenuvax) and 12 months (M-M-R II) were also analyzed. RESULTS: Among women born in the United States (n = 614), geometric mean titers (GMTs) of measles antibodies decreased with increasing birth year. For those born before 1957, 1957 through 1963, and after 1963, GMTs were 4798, 2665, and 989, respectively. Among women born outside of the United States (n = 394), there were no differences in GMTs by year of birth. Children of younger women born in the United States were less likely than those of older women to be seropositive at 6, 9, or 12 months. The response to the vaccines varied by maternal birth year for children of women born in the United States. Among 9-month-old children, 93% of those whose mothers were born after 1963 responded, compared with 77% and 60% of those whose mothers were born in 1957 through 1963 and before 1957, respectively. Among 12-month-old children, 98% of those born to the youngest mothers responded, compared with 90% and 83% of those whose mothers were born in 1957 through 1963 and before 1957. The responses of children of women born outside of the United States were not associated with maternal year of birth. CONCLUSIONS: An increasing proportion of children in the United States will respond to the measles vaccine at younger ages because of lower levels of passively acquired maternal measles antibodies.

Adult↗
PubMed1995

Roles of nitric oxide in tumor growth.

A subclone of the human colon adenocarcinoma cell line DLD-1, which grew reproducibly as subcutaneous tumors in nude mice, was isolated. Such cells, when engineered to generate nitric oxide (NO) continuously, grew more slowly in vitro than the wild-type parental cells. This growth retardation was reversed by the addition of N-iminoethyl-L-ornithine. In nude mice, however, the tumors from these cells grew faster than those derived from wild-type cells and were markedly more vascularized, suggesting that NO may act as part of a signaling cascade for neovascularization. Recent observations that the generation of NO in human breast and gynecological cancers correlates positively with tumor grade are consistent with this hypothesis. We suggest that NO may have a dual pro- and antitumor action, depending on the local concentration of the molecule.

Adenocarcinoma↗
PubMed1995

The L-arginine:nitric oxide pathway is the major source of plasma nitrite in fasted humans.

15N guanidino-labelled L-arginine was infused into fasted human volunteers giving, at equilibrium, a stable 1:10 ratio of 15N to 14N arginine in the plasma. Separate GC-MS assays were used to compare the degree of enrichment of plasma arginine, nitrite and nitrate and thus define the quantitative relationship between the L-arginine:nitric oxide (NO) pathway and the formation of these oxides of nitrogen. 15N nitrite enrichments rose to 8.3% (SD 0.5), five hours after the start of the infusion. In contrast, 15N nitrate enrichments apparently rose to only 1.6% (SD 0.4) at this time. This discrepancy could be explained by our finding that the commonly used Tesch GC-MS nitrate assay is subject to considerable interference from non-nitrate sources in plasma. Taking this into account, nitrate enrichments were similar to those observed for plasma nitrite. These results therefore indicate that the measurement of these compounds in plasma is a valid indicator of NO generation in fasted humans.

Adult↗
PubMed1995

The role of the continence adviser in England and Wales.

Continence advice in England and Wales is a relatively new specialism within nursing and, over the past 20 years, the number of continence advisers has grown substantially. There are, however, no formal qualifications for the role and the service has grown up in a piecemeal fashion. A study carried out by the Social Policy Research Unit of the University of York sought to answer basic quantitative questions about: (1) the number of continence advisers in post, their professional backgrounds and so on; (2) the structures within which continence advisers work; and (3) the nature of their current practice; as well as more attitudinal and developmental questions about the history and future development of continence advisers' work.

England↗
PubMed1995

A postal survey of continence advisers in England and Wales.

Improved continence services have been identified as a purchasing priority for 1994-1995. A key figure in the continence team is the nurse continence adviser. However, although the Association for Continence Advice in the United Kingdom offers a set of guidelines for the role of continence adviser, the extent to which these were implemented across the country was unknown. In 1991, the Department of Health commissioned the Social Policy Research Unit of the University of York, England, to carry out a postal survey of all known continence advisers in England and Wales in order to provide basic quantitative information about the number of advisers in post, their professional qualifications, the structures in which they worked, and the nature of current practice. In this paper a brief resumé of some of the main findings from the survey, which included both quantitative and qualitative data, is presented. The role of the continence adviser as a clinical nurse specialist and some of the implications for current practice are also discussed.

Adult↗
PubMed1994

A rapid and simple method for the measurement of nitrite and nitrate in plasma by high performance capillary electrophoresis.

Quantification of nitric oxide in vivo is difficult because of its short half-life. Instead the oxidised products, nitrite and nitrate, are commonly used as indices of nitric oxide generation. We describe here a simple method for the measurement of nitrite and nitrate in plasma using high performance capillary electrophoresis. Plasma standard curves gave regression coefficients of 0.98 for nitrite and 0.99 for nitrate with an intra-assay coefficient of variance of 4.6% for 50 microM nitrite (n = 10) and 1.2% for 50 microM nitrate (n = 10). The assay allows measurement of nitrite and nitrate in a single analysis requiring minimal sample preparation, and with the sensitivity to detect both basal and physiological changes in plasma nitrite and nitrate.

Biomarkers↗
PubMed1994

A 'post-honeymoon period' measles outbreak in Muyinga sector, Burundi.

In Muyinga sector, Burundi, an area with good vaccination levels against measles and recent low incidence of measles, a major outbreak of measles in 1988 raised questions about the efficacy of the immunization programme. To help answer these questions, we 1) reviewed programme data on doses of measles vaccine administered, vaccine coverage, and measles incidence, and 2) conducted a census of the affected area to examine vaccine efficacy and measles mortality. We found that between 1980 and 1988 in Burundi, 1) measles vaccine coverage by age 1 had increased from 0% to 55%, 2) the incidence of reported measles cases declined from 12.1/1000 to 6.2/1000, 3) reported measles mortality dropped from 0.18/1000 to 0.08/1000, and 4) the interepidemic period had increased from 25 to 35 months. In the census, the best estimate of measles vaccine efficacy administered at 9 months of age was 73%. Measles increased the risk of death by 2.5-fold with the effect limited to the first month after measles. This outbreak demonstrated the 'post-honeymoon period' epidemic predicted by mathematical models in which outbreaks occur among accumulated susceptibles in a partially immunized population. Understanding this phenomenon is important in providing a basis for improved strategies of measles control. Such outbreaks present new challenges to newly maturing immunization programmes in improving skills in surveillance, outbreak investigation, and public relations.

Burundi↗
PubMed1994

Controlled trial of anti-tuberculous chemotherapy for two years in Crohn's disease.

One hundred and thirty patients with active symptoms of Crohn's disease were treated in a double blind randomised controlled trial with rifampicin, isoniazid, and ethambutol, or identical placebos for up to two years. All other treatment considered necessary was continued. Analyses were based on 126 patients, 63 in each treatment group. Thirty seven in the active and 30 in the placebo group had previous surgical procedures. There was no difference in concomitant treatment between the two groups. Thirty in the active and 46 in the placebo groups were taking corticosteroids at entry to the trial. Forty eight of 63 patients in the active and 49 of 63 in the placebo group, completed at least 12 months' therapy. Reasons for early withdrawal included pregnancy, adverse reaction, and failure to comply. There was no significant difference in the mean number of months completed between the two groups. Nineteen adverse reactions were recorded for 17 patients in the active group compared with three reactions in patients on placebo. All of the nine patients withdrawn early because of adverse reactions were in the active group. Fifteen patients on active treatment and 14 on placebo had surgery during the trial with no difference in the type of surgery required between the groups. Radiological assessments based on 98 patients at the end of the trial showed no significant differences between groups in changes of extent of disease. More patients developed strictures on placebo compared with active treatment but without a statistically significant difference. No differences were found between groups for the total prednisolone dose or the number of days on which prednisolone dose was 10 mg or above. Serial measurements of body weight and Crohn's disease activity index (CDAI) together with blood values for albumin, haemoglobin, white cell count, and platelets showed no consistent different differences between groups. There were occasional significant differences for some of these values between groups, which were not sustained. The trail provides little evidence of tangible benefit from the trail treatment.

Adolescent↗
PubMed1994

Sex-specific differences in mortality after high-titre measles immunization in rural Senegal.

Administration of high-titre measles vaccine (Edmonston-Zagreb (EZ) at > 10(5) plaque-forming units (PFU) per dose) before the age of 9 months has been recommended in areas with high measles mortality before the routine age of immunization after 9 months. The study compares the long-term survival after high-titre measles immunization at 5 months of age with that following routine immunization with standard-titre vaccine at 10 months of age. At 5 months of age the high-titre group received Edmonston-Zagreb (EZ-HT, 5 months) or Schwarz (SW-HT, 5 months) at titres > 10(5) PFU per dose, while the standard-titre group received placebo at 5 months of age and < 10(4) PFU per dose of Schwarz vaccine at 10 months (SW-std, 10 months). All the children were followed up to at least 36 months of age. The mortality ratio (MR) for infants in the EZ-HT, 5 months and SW-HT, 5 months groups was 1.32 (P = 0.089) and 1.45 (P = 0.092), respectively, which did not differ significantly from that of recipients of the SW-std, 10 months. The higher MR among recipients of the high-titre vaccines was due to the significantly lower survival among females compared with the females who received SW-std vaccine (EZ-HT, 5 months MR = 1.76, P = 0.013; SW-HT, 5 months MR = 2.14, P = 0.017). For children aged 5-10 months the high-titre measles vaccine did not increase mortality relative to unvaccinated children who had received placebo.

Bias↗
PubMed1993

Age-specific differences in the relationship between oral contraceptive use and breast cancer.

BACKGROUND: Nearly all studies have suggested that the use of oral contraceptives (OC) is not associated with the aggregate risk of breast cancer diagnosed in women aged 20-54 years. Because of age-specific differences in the breast cancer-parity relationship and because of age-specific differences in other breast cancer risk factors, the Centers for Disease Control reexamined data from the Cancer and Steroid Hormone Study (CASH) to assess whether OC use has different effects on the risk of breast cancer at different ages of diagnosis. METHODS: This population-based case-control study was designed to examine the relationship between the use of OC and the risk of breast, ovarian, and endometrial cancer. CASH was conducted in eight geographic areas in the United States during 1980-1982. All participants were interviewed at home with a pretested standardized questionnaire including a calendar of life events and a photograph book of all pills marketed in the United States. RESULTS: We found that the relationship between the risk of breast cancer and OC use appeared to vary by the age at diagnosis. Among women aged 20-34 years at diagnosis or interview, those who had ever used OC had a slightly increased risk of breast cancer (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.0-2.1) compared with women of the same ages who had never used OC. Among these women, there were no trends of increasing or decreasing risk with any measure of OC use. Among women aged 35-44 years, there was no association between OC use and breast cancer. Among women aged 45-54 years, those who used OC had a slightly decreased risk of breast cancer (OR, 0.9; 95% CI, 0.8-1.0). Among these women, risk estimates decreased significantly with increasing time since first and last use. CONCLUSIONS: Although the slightly increased risk estimates for the youngest women were compatible with findings by other investigators, the decreased risk estimates for the oldest women have not been described in as many studies. Available data provide no reasons to change prescribing practices or the use of OC that are related to the breast cancer risk.

Adult↗
PubMed1992

Obesity at diagnosis of breast carcinoma influences duration of disease-free survival.

OBJECTIVE: To study disease-free survival at 10 years in relation to obesity at the time of diagnosis. DESIGN: A prospective study of consecutively treated patients with primary breast cancer. SETTING: Memorial Sloan-Kettering Cancer Center, New York. PATIENTS: Nine hundred twenty-three women treated by mastectomy and axillary dissection. MAIN RESULTS: Women who were obese (25% or more over optimal weight for height) at the time of primary breast cancer treatment were at significantly greater risk for recurrence (42%) compared with nonobese patients (32%) 10 years after diagnosis (P less than 0.01). In multivariate analyses, obesity remained a statistically significant prognostic factor after controlling for measured tumor size, number of positive axillary lymph nodes, age at diagnosis, and adjuvant chemotherapy with a hazard ratio of 1.29 (95% CI, 1.0 to 1.67). When analyses were restricted to the 557 patients free of lymph node metastases, the hazard ratio of recurrence associated with obesity was 1.59 (CI, 1.06 to 2.39); 32% of obese patients developed recurrent disease compared with 19% of nonobese women. CONCLUSIONS: Obesity at the time of diagnosis is a significant prognostic factor that may limit the reduction in breast cancer mortality attainable through detection at an early stage of disease. Because obesity and the risk for breast cancer increase with age, interventions that encourage weight control may influence breast cancer survival rates.

Adult↗