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Biomedical subjects

M C White

Publications and source records attributed to M C White.

At least 73 records · Page 4Linked to original sources
PubMed1995

Effects of basic fibroblastic growth factor on the function and proliferation of human clinically non-functional pituitary adenomas which secreted glycoprotein hormones in vitro.

The effects of human recombinant basic fibroblastic growth factor (bFGF) on the secretion, viability, proliferation, attachment and morphology of ten dispersed human clinically non-functional (NF) adenomas were examined in vitro. Four clinically NF adenomas secreting FSH and/or LH in vitro were unaffected by 10 nM bFGF over a 4-h period. Over 4 days 10 nM bFGF stimulated LH secretion (66% and 72%, P < 0.01) from two out of seven clinically NF adenomas secreting LH, whilst FSH (three tumours) and alpha-subunit secretion (three tumours) were unaffected. One adenoma co-secreting LH and alpha-subunit and one secreting LH alone were studied over 21 days; LH secretion fell progressively, but the decline was significantly less (P < 0.05) with bFGF (10 nM) treatment after 14 and 21 days in both adenomas, whilst the fall in alpha-subunit secretion was unaffected by bFGF treatment. A 24-h GnRH test performed at the start and end of the 21-day period in one of these tumours showed an increase in both basal and stimulated LH secretion in the bFGF-treated group over control (124%, P < 0.001). There was no effect of bFGF (10 nM) on viability, S-phase proliferation, attachment or morphology of adenoma cells over a 4-day period. These results suggest that bFGF has a role in tumorous LH secretion from these adenomas, but is not mitogenic (at least over 4 days) and is without effect on other parameters of in vitro differentiated function.

Adenoma↗
PubMed1995

Effect of glycoprotein and protein hormones on human meningioma cell proliferation in vitro.

Speculation that meningiomas are subject to female hormone influence is supported by their higher incidence in women and reports of exacerbation of symptoms during pregnancy and the luteal phase of the menstrual cycle. Previous reports have concentrated on the effects of the steroid hormones oestradiol and progesterone on meningioma proliferation. In this study we have investigated the roles of the glycoproteins LH, FSH and human chorionic gonadotrophin (hCG), and the protein hormones prolactin (PRL) and human placental lactogen (hPL) on the proliferation of human meningiomas in vitro. The three glycoproteins had an inhibitory effect on meningioma proliferation ranging from 5.0-50.0%, 10.0-63.0% and 2.4-34.0% at the highest concentrations of LH (25 mIU/ml), FSH (15 mIU/ml) and hCG (30 IU/ml) respectively. Cultures were also treated with PRL (100 and 200 ng/ml) and hPL (5 and 10 ng/ml) and the protein hormones had a stimulatory effect on cell proliferation of 12.0-55.5% and 11.4-73.6% when treated with 200 ng/ml PRL and 10 micrograms/ml hPL respectively. Our data suggest that increasing levels of the protein hormones PRL and hPL, falling levels of hCG and the absence of LH and FSH in the second and third trimesters of pregnancy may play a role in the acceleration of meningioma growth in these stages of pregnancy.

Adult↗
PubMed1995

Angina, functional impairment and physical inactivity among Mexican-American women with depressive symptoms.

There has been a long-standing interest in the relationship between cardiovascular disease (CVD) and psychiatric morbidity, specifically depressive symptoms. The aims of this study were to determine the following: 1. The relationship between the presence of angina and depressive symptoms; 2. The influences of sociodemographic covariates on this relationship; and 3. The effects of functional impairment or inactivity level in mediating the relationship between angina and depressive symptoms. The data utilized for this study was from the Hispanic Health and Nutrition Examination Survey (HHANES) on 1,558 Mexican American women. The survey was cross sectional, conducted in 1982-84. The dependent variable was depression as measured by the Center for Epidemiologic Depression Scale (CES-D). The independent variable was the presence of angina as measured by the Rose Questionnaire. Covariates included functional impairment, physical activity, age, education, acculturation, poverty level, marital status, and work status. The findings suggest that functional impairment has a stronger association with depressive symptoms than angina or physical inactivity. Significant sociodemographic variables include single marital status and poverty. Comorbidity has been a neglected area of research for Mexican American women, but this study suggests that functional impairment is a more important factor associated with depressive symptomatology than angina.

Activities of Daily Living↗
PubMed1994

Interleukin-6 (IL-6) production and cell growth of cultured human ameningiomas:-interactions with interleukin-1 beta (IL-1 beta) and interleukin-4 (IL-4) in vitro.

We examined the production of interleukin (IL)-6 by human meningioma cells in vitro, and the effects of IL-1 beta and IL-4 on IL-6 production and meningioma cell growth. The histological classification of the tumours studied included transitional, syncytial, fibroblastic and atypical. All 10 meningiomas studied produced IL-6 (range 0.22-7.6 ng/ml/10(6) cells/24 h). Separate addition of IL-1 beta or IL-4 to cultures increased IL-6 production up to ten fold, and two to three fold, respectively. Growth studies with IL-6 indicated that this cytokine significantly increased terminal cell density at a concentration greater than 1 ng/ml in 60% of the meningioma cultures studied. IL-1 beta caused a significant decrease in the terminal cell density in 25% of the meningioma cultures studied whereas IL-4 had a tendency to significantly inhibit growth in 16.6% of the cultures. These data suggest that IL-6 production by meningiomas can be modified by other cytokines and secondly, that IL-6, IL-1 beta and IL-4 can modify growth in vitro and may act as autocrine factors in vivo. By further determining the cytokine profiles within meningiomas and their effects, a better understanding of meningioma growth characteristics may be obtained.

Cell Division↗
PubMed1994

Exacerbations of childhood asthma and ozone pollution in Atlanta.

Asthma prevalence and mortality due to asthma have been increasing during the last decade, and both the rates and the increases in rates have been higher for blacks than whites and higher for children than adults. Whether environmental factors such as air pollution contribute to these increases is unknown. The purpose of this study was to examine the relationship between emergency visits to a hospital for childhood asthma and exposure to ozone in an indigent, predominantly black population. Data were collected by abstracting clinical records for all children with asthma or reactive airway disease in one public hospital during the summer of 1990. From June 1, 1990, to August 31, 1990, 609 visits were made by children aged 1 to 16 years to an emergency clinic for treatment of asthma or reactive airway disease. Monitoring data indicated that maximum ozone levels equalled or exceeded 0.11 ppm on 6 days during the study period. The average number of visits for asthma or reactive airway disease was 37% higher on the days after those 6 days (from 6:00 PM to 6:00 PM the next day) than on other days (95% CI, RR = 1.02-1.73). The results of the study suggest that among black children from low-income families, asthma may be exacerbated following periods of high ozone pollution.

Adolescent↗
PubMed1994

Surveillance of intravenous catheter-related infections among home care clients.

BACKGROUND: Infection control in home care is an important area of study, and infection related to home infusion therapy is one component. METHODS: According to billed supplies from a 6-month period, we identified clients receiving intravenous care and conducted a chart review to determine characteristics and infection status. We reviewed each client from the start of a continuous home care period through April 30, 1992. RESULTS: Care of the catheters was done by nurses, family care givers, or the clients themselves. Intravenous catheter-related infections-site infections and bacteremia-occurred in three (4.5%) of the sample of 67; bacteremia occurred in one (1.5%). Incidence density was 12.5 infections per 10,000 catheter days (4.2 bacteremias per 10,000 days). Among those with central lines who remained without infection, 22.9% had the same line in place for 90 days or more. Among those with peripheral lines who remained without infection, 14.3% had a peripheral line, which was changed during home care, for 30 days or longer. CONCLUSIONS: Home care agencies seeking accreditation from the Joint Commission on the Accreditation of Healthcare Organizations need to establish surveillance systems; this may be one method to monitor device-related infections and to determine baseline rates.

Adolescent↗
PubMed1994

Hyperthyroidism secondary to a pituitary adenoma secreting TSH, FSH, alpha-subunit and GH.

A 51-year-old man had been treated for hyperthyroidism with antithyroid drugs for 8 years. He was then found to have a large pituitary adenoma with biochemical evidence of overproduction of TSH, FSH and alpha-subunit. Subsequent immunocytochemical and tissue culture studies confirmed secretion of these hormones. In addition, the tumour stained for GH and was capable of GH production in vitro. This combination of hormones produced by a pituitary adenoma has not been previously reported.

Adenoma↗
PubMed1994

Effects of insulin-like growth factor-I on growth hormone and prolactin secretion and cell proliferation of human somatotrophinomas and prolactinomas in vitro.

OBJECTIVE: IGF-I inhibits GH secretion from normal and some tumorous pituitary tissue, and has been shown to be mitogenic for gonadotrophinoma cells in vitro. It is not known whether IGF-I affects somatotrophinoma cellular proliferation or the secretion of other hormones, such as PRL and alpha-subunit, which are often co-secreted by these tumours. We have therefore examined the effects of IGF-I on proliferation and hormonal secretion of human somatotrophinomas and prolactinomas in vitro. DESIGN: Pituitary adenoma tissue was dispersed to single cells in monolayer culture. The effects of 100 nM IGF-I on GH, PRL and alpha-subunit secretion were determined over 4-hour and over 4-day periods, and a 4-day dose-response study using 1-100 nM IGF-I was performed on two tumours. Adenoma cell S-phase proliferation was determined after bromodeoxyuridine incorporation for 1 hour after 4 days, using a double immunostaining method. RESULTS: Over 4 hours, 100 nM IGF-I had no effect on GH, PRL or alpha-subunit secretion in 7 tumours. Over 4 days, 100 nM IGF-I reduced GH secretion in 5/8 somatotrophinomas (range 17-84%, P < 0.05) compared to controls, with tumours responding to IGF-I having lower basal serum and in-vitro GH levels than tumours unaffected by IGF-I (P < 0.05). There was no effect on alpha-subunit secretion in any of the three tumours studied. PRL cosecretion was increased in 3/5 somatotrophinomas compared to control (20, 30 and 37%, P < 0.05), with tumours responding to IGF-I being associated with lower basal serum and in-vitro PRL levels than those tumours unaffected by IGF-I. IGF-I also increased PRL secretion in 2/2 prolactinomas (27 and 32%, P < 0.05) compared with control. GH was inhibited and PRL secretion was stimulated by 1 and 10 nM IGF-I in the two dose-response studies. The proliferative labelling index did not exceed 1.9% in any tumour and no proliferative effect was found with 100 nM IGF-I in any somatotrophinoma. CONCLUSION: IGF-I inhibited tumorous GH in 62% and stimulated PRL secretion in 71% of tumours over 4 days, without affecting alpha-subunit secretion or being mitogenic for somatotrophinoma cells in vitro. No hormonal effects were observed over short (4-hour) incubations. IGF-I may be a newly recognized factor directly stimulating tumorous PRL secretion.

Adenoma↗
PubMed1994

Occupational hydrocarbon exposure and diabetic nephropathy.

Exposure to hydrocarbons has been implicated in the pathogenesis of glomerulonephritis but its role in the development of diabetic nephropathy remains unknown. Three groups of patients with Type 1 diabetes of over 10 years duration were studied. Group 1 comprised 45 patients (23 F) with no diabetic nephropathy (urinary albumin excretion (AER) < 30 mg 24 h-1), group 2 comprised 37 patients (17 F) with incipient diabetic nephropathy (AER between 30-300 mg 24 h-1), and group 3 comprised 31 patients (15 F) with overt diabetic nephropathy (AER > 300 mg 24 h-1). The groups were comparable for age, sex, duration of diabetes, recent glycaemic control, social class, and residential area. Patients were assessed blindly by a validated questionnaire and interview for hydrocarbon exposure, consumption of tobacco, analgesic agents, and alcohol. Exposure scores to hydrocarbons derived from the questionnaire were significantly higher in patients with incipient and overt diabetic nephropathy with smoking adjusted odds ratios of 3.6 and 5.2, respectively. The consumption of alcohol, analgesic agents, tobacco, and smoking habits were similar in the three groups. In conclusion, hydrocarbon exposure may be a key environmental factor in the development of diabetic nephropathy in patients with Type 1 diabetes.

Adult↗
PubMed1994

Evidence of oxidant injury and tubular damage in early diabetic nephropathy.

Two groups of patients with insulin-dependent diabetes mellitus of > 10 years duration and either persistent normoalbuminuria (group 1, n = 49; albumin excretion < 30 mg/day) or microalbuminuria (group 2, n = 33; albumin excretion 30-300 mg/day) were investigated for evidence of free oxygen radical activity (erythrocytic superoxide dismutase and glutathione peroxidase) and oxidant injury (serum malondialdehyde). Glomerular proteinuria (albuminuria, transferrinuria), tubular proteinuria (retinol-binding protein) and tubular enzymuria (N-acetyl-glucosaminidase and leucine aminopeptidase) were also measured. Healthy controls (n = 38) were matched for age and sex. Groups 1 and 2 were similar in terms of age, sex, duration of diabetes and recent glycaemic control. Serum cholesterol and creatinine were similar in all three groups. Free-radical activity and oxidant injury were significantly higher in groups 1 and 2 than in controls (p < 0.001). Glomerular proteinuria, tubular proteinuria and enzymuria were significantly higher in group 2 than in group 1 and controls (p < 0.01). Group 1 had significantly higher transferrinuria, tubular enzymuria and tubular proteinuria than controls. However, groups 1 and 2 were similar in degree of free oxygen radical generation and oxidant injury. In diabetic nephropathy, oxidant injury and renal tubular damage accompany and may even precede microalbuminuria. The presence of these abnormalities in the absence of glomerular proteinuria favours the hypothesis that alterations first occur in the peritubular microcirculation, which by causing oxidant injury and tubular damage, may initiate diabetic nephropathy.

Adult↗
PubMed1993

Infection control in home care agencies.

BACKGROUND: The purpose of this study was to describe the characteristics of home care agencies, including the nature of care provided and the presence of infection control standards and education. METHODS: Study design was cross-sectional and descriptive; the survey of home health agencies included questions about agency type, nature of care delivered, and infection control policies and educational programs. The sample included all directors of home care agencies in northern California. RESULTS: The response rate was 33.5%. Agency directors reported that 15.3% of their clients required high-technology nursing care; in response to a list of invasive procedures generally considered high in infection risk, more than 90% cared for urinary drainage devices, some categories of wound care, and intravenous management. Of those performing high-risk procedures, more than 75% had policies covering the procedures. Nearly all (87.7% to 100%) had policies on universal precautions, handwashing, handling of needles and sharps, and the cleaning and disinfection of equipment; however, nearly a quarter (24.6%) had no education program regarding the handling of contaminated equipment. CONCLUSIONS: Among agencies responding to this survey, care that is considered high risk for infection is delivered and the agencies for the most part have infection control policies and educational programs. Research is needed to define more clearly infection control efforts in home health care. More work is needed to adapt the knowledge of infection control in hospitals to the home setting.

California↗
PubMed1993

Description and reporting of statistical methods.

A review of the last three volumes of AJIC (1990, 1991, and 1992, numbers 1 through 3) revealed a modest use of statistics in infection control research. Discussion of the statistics most commonly used results in the following recommendations: (1) Researchers who use the t test should report the t test statistic, exact significance probabilities, and a discussion of assumptions and requirements underlying the analysis. (2) A 95% confidence interval for estimated quantities is preferred to p values. (3) The potential impact of nonresponse bias should be included in reports of survey data. (4) An adequate description of statistical methods should be included in all reports of survey data. (5) An adequate description of statistical methods should be included in all research articles.

Confidence Intervals↗
PubMed1993

The peer review process of the Journal.

The manuscript review process is a critical part of the dissemination of new science. This article reviews the components of the process, including editorial screening, peer review, and final author review of manuscripts, and notes the persons involved in each stage of the process. The editorial review process is an evolving science, and Journal policies and procedures are revised as this science gains new insights.

Peer Review, Research↗
PubMed1993

Perioperative blood contact and exposures: a comparison of incident reports and focused studies.

BACKGROUND: Occupational blood exposures among operating room personnel have been substantially underreported in incident reports. Recent research has indicated several common factors influencing exposure rates: surgical service (thoracic, neurosurgery, orthopedic), length of operation, and emergency status. METHODS: This report examines further data from a study of 8502 surgical cases in nine hospitals, in which a site coordinator and circulating nurses reported consecutive case information, including blood contacts that occurred during the procedures. For three of the participating hospitals, incident reports of blood exposures among operating room personnel that occurred during a 12-month period before the study were also tabulated. RESULTS: Incident reports underreported parenteral exposures (punctures, mucous membrane and nonintact skin contact with patient blood) by as much as a factor of 25. Individual hospital rates of occupational surgical blood exposure varied considerably. CONCLUSIONS: To ensure that resources to prevent occupational blood exposure are allocated appropriately, on the basis of actual risk, among all personnel, hospitals must actively monitor blood exposures in their operating rooms.

Blood-Borne Pathogens↗
PubMed1993

Blood contact and exposures among operating room personnel: a multicenter study.

Blood exposures are increasingly recognized as a risk for health care workers in the operating room. Trained circulating nurses supervised by site coordinators queried surgical team members about blood contact and collected data on 8502 surgical procedures from seven community and two university hospitals in 1992. Blood contact occurred during 864 cases (10.2% case-contact rate) in 1054 health care workers (12.4% person-contact rate). The parenteral exposure (punctures or cuts, mucous membranes, nonintact skin) rate was 2.2% and the cutaneous exposure (intact skin) rate was 10.2%. Blood contacts were twice as likely to be parenteral among surgeons as among other operating room personnel (odds ratio, 2.0; 95% confidence interval, 1.4 to 2.9). Of cutaneous exposures, 46.9% were from unknown sources or were surprise spatters. Logistic regression analyses indicated that risk factors associated with any blood contact (parenteral or cutaneous) were length of procedure (odds ratio, 1.51; 95% confidence interval, 1.46 to 1.56), emergency versus scheduled status (odds ratio, 1.44; 95% confidence interval, 1.21 to 1.66), selected surgical services, and the hospital. Logistic regression analyses of parenteral exposures, as compared with cases in which no contact occurred, indicated that risk factors were length (odds ratio, 1.39; 95% confidence interval, 1.31 to 1.47), thoracic surgery (odds ratio, 2.79; 95% confidence interval, 2.18 to 3.40), and university hospital versus community (odds ratio, 2.26; 95% confidence interval, 1.89 to 2.63). Parenteral exposures are clear risks to health care workers; however, it is also important to study all contact with blood in the operating room to appreciate potential risks and develop appropriate intervention strategies.

Blood-Borne Pathogens↗