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Biomedical subjects

H Mitchell

Publications and source records attributed to H Mitchell.

At least 55 records · Page 3Linked to original sources
PubMed1998

Efficacy and tolerability of losartan in hypertensive patients with renal impairment. Collaborative Group.

We evaluated the blood pressure-lowering activity, tolerability, and safety of losartan in 112 hypertensive (sitting diastolic blood pressure, 90 to 115 mm Hg) patients with chronic renal insufficiency including mild renal insufficiency (30 to 60 mL/min per 1.73 m2; n=51), moderate to severe renal insufficiency (10 to 29 mL/min per 1.73 m2; n=33), or hemodialysis (n=28). After a 3-week placebo period, once-daily losatan was administered for 12 weeks. The daily dose of 50 mg was increased to 100 mg after 4 weeks in patients whose sitting diastolic blood pressure remained > or = 90 mm Hg or was reduced by < 5 mm Hg. A second, non-angiotensin-converting enzyme inhibitor, antihypertensive drug was added after 8 weeks as needed. Twenty-four-hour creatinine clearance was determined and renal clearance studies of inulin and para-aminohippurate were done in a subset of 11 patients. Trough sitting blood pressures were reduced at the end of the first week in all groups. At weeks 4, 8, and 12, the reductions in systolic blood pressure/diastolic blood pressure averaged -11.9/-8.7, -10.8/-9.4, and -14.7/-12.1 mm Hg in patients with mild renal insufficiency; -7.7/-6.3, -13.1/-11.8, and -14.1/-10.6 mm Hg, in moderate to severe renal insufficiency; -17.0/-12.7, -19.1/-14.4, and -22.7/-18.0 mm Hg in hemodialysis. Creatinine clearance, glomerular filtration rate, and effective renal plasma flow were stable. Losartan was withdrawn in only 6 patients because ofa clinical or laboratory adverse experience. Hyperkalemia (> 6 mEq/L) requiring discontinuation of losartan occurred in only one (group 2) patient. We conclude that once-daily losartan, given as monotherapy at doses of 50 or 100 mg or in combination with other antihypertensive drugs, was effective in reducing blood pressure in hypertensive patients with chronic renal disease and that losartan regimens were well tolerated in all groups, including those on hemodialysis.

Adolescent↗
PubMed1998

The effect of benign and malignant liver disease on the tumour markers CA19-9 and CEA.

The serum concentrations of CA19-9 and carcinoembryonic antigen (CEA) were measured in 150 consecutive patients with histologically proven liver disease admitted to a liver unit for transplant assessment. A significant proportion of the cases studied had a CA19-9 above the upper limit of the reference range (35 kU/L): alcoholic liver disease (73%), primary sclerosing cholangitis (61%), primary biliary cirrhosis (60%), chronic hepatitis B (71%), chronic hepatitis C (84%), autoimmune hepatitis (36%) and hepatocellular carcinoma (54%). CEA was only elevated in a small proportion of the patients with benign liver disease and the degree of elevation was small (15-37 micrograms/L). Significantly raised CEA was observed in two patients (15%) with hepatocellular carcinoma. Statistically significant correlations were observed between the serum CA19-9 concentration and standard parameters of liver dysfunction: positive correlations with aspartate aminotransferase, alkaline phosphatase and bilirubin and negative correlations with albumin and gamma-glutamyltransferase. Positive relationships were also observed between CA19-9 and both CEA and creatinine. Both increased production of CA19-9 from biliary epithelial cells and decreased clearance due to cholestasis may be contributing to the elevation of CA19-9 in the bloodstream. Our data indicate that caution is needed in the interpretation of CA19-9 results in the presence of liver dysfunction.

Biomarkers, Tumor↗
PubMed1998

Notification of Pap smear results. A Victorian survey.

OBJECTIVE: To determine health practitioners' use of preprinted tear-off sections attached to all Papanicolaou (Pap) smear reports as a means of notifying women of their test results and to assess possible barriers to the use of these. METHOD: A questionnaire was sent to health practitioners who used the Victorian Cytology Service for their Pap smear reporting. RESULTS: A 74% response rate was achieved (1402/1886); 70.4% (987/1402) of respondents routinely used the tear-off section. Use was more common for negative Pap smear reports (62.8%) than for abnormal Pap smear reports (46.1%). The main barriers nominated by non users were a preference for an alternative approach and the impersonal nature of the communication. CONCLUSIONS: After 18 months, we conclude that preprinted tear-off sections appear to have an encouraging level of acceptability among practitioners. The laboratory has decided to maintain this initiative as a permanent feature.

Communication↗
PubMed1997

The role of cockroach allergy and exposure to cockroach allergen in causing morbidity among inner-city children with asthma.

BACKGROUND: It has been hypothesized that asthma-related health problems are most severe among children in inner-city areas who are allergic to a specific allergen and also exposed to high levels of that allergen in bedroom dust. METHODS: From November 1992 through October 1993, we recruited 476 children with asthma (age, four to nine years) from eight inner-city areas in the United States. Immediate hypersensitivity to cockroach, house-dust-mite, and cat allergens was measured by skin testing. We then measured major allergens of cockroach (Bla g 1), dust mites (Der p 1 and Der f 1), and cat dander (Fel d 1) in household dust using monoclonal-antibody-based enzyme-linked immunosorbent assays. High levels of exposure were defined according to proposed thresholds for causing disease. Data on morbidity due to asthma were collected at base line and over a one-year period. RESULTS: Of the children, 36.8 percent were allergic to cockroach allergen, 34.9 percent to dust-mite allergen, and 22.7 percent to cat allergen. Among the children's bedrooms, 50.2 percent had high levels of cockroach allergen in dust, 9.7 percent had high levels of dust-mite allergen, and 12.6 percent had high levels of cat allergen. After we adjusted for sex, score on the Child Behavior Checklist, and family history of asthma, we found that children who were both allergic to cockroach allergen and exposed to high levels of this allergen had 0.37 hospitalization a year, as compared with 0.11 for the other children (P=0.001), and 2.56 unscheduled medical visits for asthma per year, as compared with 1.43 (P<0.001). They also had significantly more days of wheezing, missed school days, and nights with lost sleep, and their parents or other care givers were awakened during the night and changed their daytime plans because of the child's asthma significantly more frequently. Similar patterns were not found for the combination of allergy to dust mites or cat dander and high levels of the allergen. CONCLUSIONS: The combination of cockroach allergy and exposure to high levels of this allergen may help explain the frequency of asthma-related health problems in inner-city children.

Allergens↗
PubMed1997

Design and methods of the National Cooperative Inner-City Asthma Study.

The National Cooperative Inner-City Asthma Study (NCICAS) was established to identify and then intervene on those factors which are related to asthma morbidity among children in the inner-city. This paper describes the design and methods of the broad-based initial Phase I epidemiologic investigation. Eight research centers enrolled 1,528 children, 4 to 9 years of age, from English- or Spanish-speaking families, all of whom resided in major metropolitan inner-city areas. The protocol included an eligibility assessment and an extensive baseline visit, during which symptom data, such as wheezing, lost sleep, changes in activities of daily living, inpatient admissions, and emergency department and clinic visits were collected. A comprehensive medical history for each child was taken and adherence to the medical regimen was assessed. Access, as well as barriers, to the medical system were addressed by a series of questions including the location, availability, and consistency of treatment for asthma attacks, follow-up care, and primary care. The psychological health of the caretaker and of the child was also measured. Asthma knowledge of the child and caretaker was determined. Sensitization to allergens was assessed by skin-prick allergen testing and exposure to cigarette smoke and the home environment were assessed by questionnaire. For more than a third of the families, in-home visits were conducted with dust sample allergen collection and documentation of the home environment, such as the presence of pets and evidence of smoking, mildew, and roaches. Urine specimens were collected to measure passive smoke exposure by cotinine assays, blood samples were drawn for banking, and children age 6 to 9 years were given spirometric lung function assessment. At 3, 6 and 9 months following the baseline assessment, telephone interviews were conducted to ask about the child's symptoms, unscheduled emergency department or clinic visits, and hospitalizations. At this time, peak flow measurements with 2-week diary symptom records were collected.

Allergens↗
PubMed1997

Characteristics of inner-city children with asthma: the National Cooperative Inner-City Asthma Study.

Asthma morbidity has increased dramatically in the past decade, especially among poor and minority children in the inner cities. The National Cooperative Inner-City Asthma Study (NCICAS) is a multicenter study designed to determine factors that contribute to asthma morbidity in children in the inner cities. A total of 1,528 children with asthma, ages 4 to 9 years old, were enrolled in a broad-based epidemiologic investigation of factors which were thought to be related to asthma morbidity. Baseline assessment included morbidity, allergy evaluation, adherence and access to care, home visits, and pulmonary function. Interval assessments were conducted at 3, 6, and 9 months after the baseline evaluations. Over the one-year period, 83% of the children had no hospitalizations and 3.6% had two or more. The children averaged 3 to 3.5 days of wheeze for each of the four two-week recall periods. The pattern of skin test sensitivity differed from other populations in that positive reactions to cockroach were higher (35%) and positive reactions to house dust mite were lower (31%). Caretakers reported smoking in 39% of households of children with asthma, and cotinine/creatinine ratios exceeded 30 ng/mg in 48% of the sample. High exposure (> 40 ppb) to nitrogen dioxide was found in 24% of homes. Although the majority of children had insurance coverage, 53% of study participants found it difficult to get follow-up asthma care. The data demonstrate that symptoms are frequent but do not result in hospitalization in the majority of children. These data indicate a number of areas which are potential contributors to the asthma morbidity in this population, such as environmental factors, lack of access to care, and adherence to treatment. Interventions to reduce asthma morbidity are more likely to be successful if they address the many different asthma risks found in the inner cities.

Allergens↗
PubMed1997

Psychosocial characteristics of inner-city children with asthma: a description of the NCICAS psychosocial protocol. National Cooperative Inner-City Asthma Study.

Previous research has demonstrated a significant reciprocal relationship between psychosocial factors and asthma morbidity in children. The National Cooperative Inner-City Asthma Study investigated both asthma-specific and non-specific psychosocial variables, including asthma knowledge beliefs and management behavior, caregiver and child adjustment, life stress, and social support. This article presents these psychosocial characteristics in 1,528 4-9-year-old asthmatic urban children and their caretakers. Caretakers demonstrated considerable asthma knowledge, averaging 84% correct responses on the Asthma Information Quiz. However, respondents provided less than one helpful response for each hypothetical problem situation involving asthma care, and most respondents had more than one undesirable response, indicating a potentially dangerous or maladaptive action. Both adults and children reported multiple caretakers responsible for asthma management (adult report: average 3.4, including the child); in addition, children rated their responsibility for self-care significantly higher than did adults. Scores on the Child Behavior Checklist indicated increased problems compared to normative samples (57.3 vs. 50, respectively), and 35% of children met the criteria for problems of clinical severity. On the Brief Symptom Inventory, adults reported elevated levels of psychological distress (56.02 vs norm of 50); 50% of caretakers had symptoms of clinical severity. Caretakers also experienced an average of 8.13 undesirable life events in the 12 months preceding the baseline interview. These findings suggest that limited asthma problem-solving skills, multiple asthma managers, child and adult adjustment problems, and high levels of life stress are significant concerns for this group and may place the inner-city children in this study population at increased risk for problems related to adherence to asthma management regimens and for asthma morbidity.

Adult↗
PubMed1997

Scleroderma and related conditions.

Systemic sclerosis is a generalized disorder characterized by fibrosis and microvascular injury in affected organs. Despite being recognized nearly 250 years ago, knowledge regarding pathogenesis remains limited, and treatment remains directed at symptomatic improvement. Early recognition of systemic sclerosis, however, is important in order to monitor for specific disease complications (i.e., fibrosing alveolitis, scleroderma renal crisis) as well as initiate manifestation specific therapies that improve quality of life.

Humans↗
PubMed1997

Effect of ethnic media on cervical cancer screening rates.

The effect on cervical screening rates of paid publicity on ethnic radio was evaluated. The radio publicity occurred during three discrete periods between 1992 and 1994. The numbers of women having Pap smears before and after the intervention were compared in postcode areas with high and low percentages of residents of non-English-speaking background. During the second and third publicity periods, when the media coverage was more intense, a larger increase in screening rates was evident in postcode areas with high percentages of women of non-English-speaking background. Across the three intervention periods, the media publicity appeared to generate an additional 6.7 per cent (95 per cent confidence interval 4.4 to 9.2 per cent) increase in screening in areas with a high proportion of women of non-English-speaking-background compared with changes in screening in areas with a low proportion of women of non-English-speaking background. Paid publicity on ethnic radio may be an effective strategy to increase cervical screening rates among women of non-English-speaking background.

Female↗
PubMed1997

Efficacies of ofloxacin, rifampin, and clindamycin in treatment of Staphylococcus aureus abscesses and correlation with results of an in vitro assay of intracellular bacterial killing.

We studied the efficacies of ofloxacin, rifampin, and clindamycin in a Staphylococcus aureus abscess model and seven antimicrobial regimens in an intracellular killing assay. Ofloxacin plus rifampin was the most effective regimen in the abscess model, and rifampin and ofloxacin were the most active regimens in the intracellular killing assay.

Abscess↗
PubMed1997

Report disclaimers and informed expectations about Papanicolaou smears: an Australian view.

The cervical cancer screening program in Australia has an emerging litigation problem. This paper reviews some recent initiatives taken to address the problem. These initiatives include the establishment of registries of women being screened, education to promote an appreciation of the limitations of screening, and the introduction of outcome standards for laboratories reporting cervical cytology. An international evidence-based definition of the standard of care is the most pressing need in the immediate future. Possible roles of report disclaimers, informed consent, improved information about the average level of accuracy of a cervical cytology report, and the use of a range of differential diagnoses in addressing the medicolegal problems of cervical screening are explored.

Australia↗
PubMed1997

The pitfalls of field trials in fish vaccinology.

Field trials are essential for accurately assessing the worth of a vaccine under actual conditions of use. Compared with the laboratory, the dynamics of the host, pathogen, and environment in a production setting can produce both subtle and dramatic differences on the performance of the vaccine and the immune response. Because of this, field trials are conducted by manufacturers in vaccine development and are required by many national regulatory agencies to evaluate safety and/or efficacy before granting vaccine licenses. Aquaculture producers, veterinarians and fish health professionals can use field trials to analyse the cost-benefit of a vaccination programme for a facility, or to compare competitive products. Vaccine field trials are more than merely using the products in the field. Small efficacy effects can result in considerable cost reductions to the fish farmer. Proper field trial design, conduct and analysis is critical to detecting these effects. However, field trials are also fraught with many pitfalls that can result in failure or misleading conclusions. The discussion regarding possible pitfalls of vaccine field trials in aquaculture is divided into two parts: 1) the art and 2) the science of successful field trials. The art of successful field trials involves dealing with the "people" aspect which is necessary for initial and continuing compliance. Meticulous planning is essential, including a written protocol to which everyone agrees by signature. The bottom line to the art of field trials is anticipation and discussion of all possible eventualities together with constant communication with the farmer and site supervisor. The science of successful fields trials involves anticipating and realizing the logistical and statistical difficulties in design and implementation. Problems often encountered are: lack of stated quantifiable purpose; low power of the test due to inherent small sample size, large variation and small margin of effect; lack of estimate for anticipated results in controls and unpredictable challenges; non-blinding design with bias and unequal treatment; one or few measures of outcome; lack of redundancy in sites selected; poor statistical design and analysis with violation of assumptions; herd effects; inability to assess long-term effects through several production cycles; and manufacturer/producer expense.

Animals↗
PubMed1996

An audit of the women who died during 1994 from cancer of the cervix in Victoria, Australia.

An audit of 73 Victorian women who died from cervical cancer during 1994 is presented. Seventy per cent of the deaths occurred in women who were > or = 50 years at the time of cancer diagnosis. Younger women had significantly better screening histories than older women, but overall only 10% of the deaths occurred among women who were adequately screened. There was no excess of deaths in rural women or in women of non-English speaking background. Four of the 6 deaths in women who were diagnosed with cancer while < 35 years of age occurred in adequately screened women. If this finding is confirmed in a larger series, it raises questions about the ability of Papanicolaou screening to control disease in this age group.

Adenocarcinoma↗
PubMed1996

Consequences of current patterns of Pap smear and colposcopy use.

OBJECTIVES - To describe age specific frequencies of Pap smear and colposcopy use in the Australian Capital Territory (ACT) and to estimate the cumulative effects of current patterns of use. SETTING - Frequencies of Pap smear and colposcopy use were estimated for the financial year from 1 July 1989 to 30 June 1990. Eligible women were between the ages of 15 and 74, living in the ACT. METHODS - Data collected from a 10% sample of subjects enrolled with Medicare and from the only public pathology laboratory in the ACT were used to estimate age specific frequencies. The expected number of deaths from cervical cancer in the ACT in the absence of a screening programme was estimated by applying Australian age specific mortality rates for cervical cancer between 1960 and 1964 to the 1989 ACT population. A life table approach was used to simulate the cumulative risk of colposcopy - given current age specific rates - on a hypothetical cohort of 1000, 15 year old women. RESULTS - Forty four per cent (95% confidence interval (CI) 42.9 to 44.9) of women had a Pap smear and 2.5% had colposcopy (95% CI 2.4 to 2.6). Two and a half percent of 15 to 24 year old women had colposcopy (95% CI 1.9 to 3.1). The ratio of women having Pap smears to women having colposcopy was 17-8:1 (95% CI 17.7 to 17.9). An estimated 247 women had colposcopy for every cervical cancer death; in the 15 to 24 year old age group this ratio was 47900:1. A 15 year old woman exposed to current rates of colposcopy (adjusted for hysterectomy) has a 76.8% chance of having a colposcopy during her life time. CONCLUSIONS - Many more women will have colposcopy than will develop cervical cancer, which undermines the cost effectiveness of Australia's cervical cancer screening programme.

Adolescent↗
PubMed1996

Defining response of ovarian carcinoma to initial chemotherapy according to serum CA 125.

PURPOSE: To produce definitions based on serial CA 125 levels to measure response of ovarian carcinoma in patients receiving first-line chemotherapy. PATIENTS AND METHODS: Definitions were derived from analysis of 277 patients in North Thames Ovary Trial 3. Patient data were then incorporated into a computer program and tested against 254 patients in North Thames Ovary Trial 4 and 458 patients in Gynecologic Oncology Group (GOG) protocol 97. For optimum detection of response, three response definitions have been combined into a computer program. The precise definitions use mathematic logic and take account of factors such as intervening samples. Response to a specific treatment has occurred if after two samples there has been a 50% decrease, confirmed by a fourth sample (50% response), or a serial decrease over three samples of greater than 75% (75% response). The final sample has to be at least 28 days after the previous sample. RESULTS: Six hundred twenty of 989 patients were considered assessable for response according to CA 125 level. Only two patients (0.3%) had a CA 125 response at the time of clinical progression. The CA 125 response rate was 62% and 54% in the North Thames trials. In the GOG trial, it was 66% in all 317 patients assessable for CA 125 and 67% in 221 patients whose CA 125 level was not measurable according to GOG criteria, compared with a GOG-defined response rate of 62%. The sensitivity for detecting GOG-defined response was at least 68%. CONCLUSION: Definitions based on a 50% or 75% decrease of CA 125 levels have been shown reliably to define partial response of ovarian cancer in patients receiving first-line chemotherapy. These definitions should be used in addition to or instead of standard response criteria.

Antineoplastic Agents↗