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Biomedical subjects

H Mitchell

Publications and source records attributed to H Mitchell.

At least 37 records · Page 2Linked to original sources
PubMed1999

Guidelines for development and application of aquatic animal health regulations and control programs. AVMA Aquaculture and Seafood Advisory Committee.

The creation of sound health regulations or disease control programs for any animal species is a complex endeavor. When the diverse stakeholder interests related to aquaculture are considered, this endeavor becomes daunting. The AVMA Aquaculture and Seafood Advisory Committee designed the following guidelines as a tool to assist aquatic animal health professionals who discuss potential regulations or control programs with government and industry entities. The guide focuses on determining whether a regulation or program is appropriate and, if so, developing a suitable and effective aquatic animal health plan. The Aquaculture and Seafood Advisory Committee was established in 1992 as an ad hoc committee of the AVMA Executive Board. The committee is composed of 9 veterinarians with diverse interests in aquaculture and seafood, and one non-veterinarian who represents the aquaculture industry. Participants from the USDA/APHIS and FDA serve as consultants to the Committee.

Animals↗
PubMed1999

A randomized clinical trial to reduce asthma morbidity among inner-city children: results of the National Cooperative Inner-City Asthma Study.

OBJECTIVE: To evaluate a family-focused asthma intervention designed for inner-city children 5 to 11 years old with moderate to severe asthma. STUDY DESIGN: Randomized, multisite, controlled trial to minimize symptom days (wheeze, loss of sleep, reduction in play activity) measured by a 2-week recall assessed at 2-month intervals over a 2-year follow-up period. The intervention was tailored to each family's individual asthma risk profile assessed at baseline. RESULTS: Averaged over the first 12 months, participants in the intervention group (n = 515) reported 3.51 symptom days in the 2 weeks before each follow-up interview compared with 4.06 symptom days for the control group (n = 518), a difference of 0.55 (95% CI, 0.18 to 0.92, P =.004). The reduction among children with severe asthma was approximately 3 times greater (1.54 d/2 wk). More children in the control group (18.9%) were hospitalized during the intervention compared with children in the intervention group (14. 8%), a decrease of 4.19% (CI, -8.75 to 0.36, P =.071). These improvements were maintained in the intervention group during the second year of follow-up, during which they did not have access to the asthma counselor. CONCLUSIONS: We demonstrated that an individually tailored, multifaceted intervention carried out by Masters-level social workers trained in asthma management can reduce asthma symptoms among children in the inner city.

Asthma↗
PubMed1999

Results of the National Cooperative Inner-City Asthma Study (NCICAS) environmental intervention to reduce cockroach allergen exposure in inner-city homes.

BACKGROUND: Cockroach allergen is important in asthma. Practical methods to reduce exposure are needed. OBJECTIVE: We sought to evaluate the effectiveness of house cleaning and professional extermination on lowering cockroach antigen levels in inner-city dwellings. METHODS: As part of the National Cooperative Inner-City Asthma Study intervention, 265 of 331 families with asthmatic children who had positive skin test responses to cockroach allergen consented to a professional home extermination with 2 applications of a cockroach insecticide (Abamectin, Avert) combined with directed education on cockroach allergen removal. On a random subset of 48 homes undergoing cockroach extermination in the intervention group, Bla g 1 was measured in settled dust from the kitchen, bedroom, and TV/living room. The first sample was collected 1 week before extermination, with additional samples after the exterminations at approximately 2, 6, and 12 months after the first sample. Self-reported problems with cockroaches were collected at baseline and after 12 months of follow-up in both the intervention and control group. RESULTS: The geometric mean kitchen level of Bla g 1 decreased at 2 months (33.6 U/g) relative to preextermination levels (68.7 U/g, P <.05). The percent of kitchens with over 8 U/g of Bla g 1 followed a similar pattern, but only the decrease from preextermination to 6-month levels was significant (86.8% vs 64.3%, P <.05). By the 12-month visit, the allergen burden had returned to or exceeded baseline levels. Except for an increase in the bedroom at 2 months (8.9 U/g vs 11.1 U/g, P <.05), no other significant change was seen. Only about 50% of the families followed the cleaning instructions; no greater effect was found in these homes. Self-reported problems with cockroaches showed no difference between the intervention and control group after 1 year of follow-up. CONCLUSIONS: Despite a significant, but short-lived, decrease the cockroach allergen burden remained well above levels previously found to be clinically significant.

Allergens↗
PubMed1999

Effect of antenatal dexamethasone therapy on maternal plasma human chorionic gonadotrophin, oestradiol and progesterone.

The aim of this study was to determine whether the current regimen of dexamethasone administration to induce fetal lung maturation affected the circulating concentrations of placental hormone. A standard regimen of dexamethasone that comprised two doses of 12-mg intramuscular injections, 12 h apart was administered to 12 pregnant women to promote fetal lung maturation in anticipation of premature delivery before 34 completed weeks of gestation. Blood samples were collected before starting the dexamethasone therapy, 24 h, and 48 h after completing therapy for the measurement of the plasma concentrations of human chorionic gonadotrophin (HCG), oestradiol and progesterone. There was a progressive fall in the plasma concentrations of HCG following dexamethasone therapy (P = 0.049 and P = 0.034, 24-h and 48-h post therapy respectively). There was an initial fall in the plasma concentrations of oestradiol after dexamethasone therapy (z = 3.059; P = 0.002, 24-h post therapy), which recovered by 48 h (P = 0.239). There was no difference between the plasma concentrations of progesterone at the three time points. The effect of dexamethasone on HCG concentrations suggests that it has a direct inhibitory effect on placental hormone synthesis or secretion. Further studies are needed to define the mechanism of action of dexamethasone on placental HCG production.

Adult↗
PubMed1999

Division of responsibility for asthma management tasks between caregivers and children in the inner city.

This investigation examined caregiver and child perceptions of the division of responsibility for asthma management tasks in families. The study sample included 789 children with asthma, aged 6 to 9 years, who lived in the inner city. These children and their primary caregivers completed the Asthma Responsibility Interview. The correlation between the caregiver's and child's ratings of the child's responsibility was low (.19), with children rating themselves as more responsible than their caregivers rated them. Caregiver and child ratings of the child's responsibility increased with the child's age; however, caregivers' ratings of their own responsibility remained constant over the age range studied. Kappa statistics ranged from -.03 to .12, with up to 16% of children reporting less responsibility for self-care than was indicated by the caregiver. More than one third of families reported four or more asthma caregivers. The discrepancy between the caregiver's and child's perceptions and the involvement of multiple caregivers raise the possibility of unintentional nonadherence.

Asthma↗
PubMed1999

Outcome after a Pap smear report of low-grade abnormality: a longitudinal comparative study.

The rate of subsequent diagnosis of high-grade cervical abnormality was studied among women whose first Pap smear in 1994 was reported as being negative or from the category of low-grade abnormality (excluding CIN 1). Regardless of the degree of low-grade abnormality reported on the entry smear, the rate of subsequent high-grade disease was 3.3 cases per 100 years of follow-up. The rate of subsequent high-grade disease among women with negative Pap smear reports was 0.23 to 0.45 cases per 100 years of follow-up. Within each cohort, a small number of cases of invasive cervical cancer were diagnosed in the 2 years after the entry smear. These data indicate that Pap smear reports which are coded to the registry squamous cell code of 'mild atypia' (with or without evidence of human papillomavirus effect) have a significantly higher risk of emerging high-grade cervical disease than negative Pap smear reports (including those with minor reactive and/or inflammatory change). It is suggested that the former have a uniform recommendation of repeating the smear in 1 year and the latter in 2 years.

Adenocarcinoma↗
PubMed1999

Failure of IGF-I and IGFBP-3 to diagnose growth hormone insufficiency.

BACKGROUND: Growth hormone insufficiency (GHI) is diagnosed conventionally by short stature and slow growth, and is confirmed by diminished peak GH response to a provocation test. Insulin-like growth factor I (IGF-I) and IGF binding protein 3 (IGFBP-3) have previously been considered individually OBJECTIVE: To test the hypothesis that the combined analysis of IGF-I and IGFBP-3 could act as a surrogate marker for the diagnosis of GHI. DESIGN: Reference ranges for IGF-I and IGFBP-3 were calculated using 521 normal individuals. A retrospective analysis was performed on 318 children referred for investigation of short stature. RESULTS: No significant difference was found between either the IGF-I or IGFBP-3 standard deviation scores (SDSs) in children with and without GHI. If the requirement were for both tests to be positive (< -2 SDS) for a diagnosis of GHI, then 99% of children without GHI would be correctly identified; however, the sensitivity of the test was only 15%. CONCLUSIONS: Neither IGF-I nor IGFBP-3 alone is a marker for GHI. In addition, they cannot be used as an effective screening test in combination.

Adolescent↗
PubMed1999

Monitoring interval cancers in an Australian mammographic screening programme.

OBJECTIVE: To report the interval cancer rate for BreastScreen Victoria. DESIGN: Electronic linkage of Breast Screen Victoria records with those of the Victorian Cancer Registry. Interval cancers were expressed as a proportion of the underlying incidence (proportional incidence), and the sensitivity as the number of screen detected invasive breast cancers divided by the total number of invasive breast cancers diagnosed in the screening interval. SETTING: Victoria, Australia where biennial screening is provided to women aged 40 and older. SUBJECTS: Victorian women aged 40-79 who attended first round screening in 1994 (103,023 women) and 1995 (107,057 women). RESULTS: The sensitivity of screening mammography for the two year interval increased with age (p for trend < 0.001) and was 49.4% in women aged 40-49, 68.6% in 50-59 year old women, 80.7% in 60-69 year old women, and 85.2% in women aged 70-79. The proportional incidence in the first year after screening was 59% in 40-49 year old women and 27% in women aged 50-69. In the second year the proportional incidence was 93% in 40-49 year old women and 54% in women aged 50-69. CONCLUSIONS: Interval cancers comprise such a large proportion of the expected number of cancers in 40-49 year old women that the benefit of screening is likely to be low. For women aged 50-69, the proportional incidence found in this study was similar to those found in the UK programmes.

Adult↗
PubMed1999

The relationship between psychosocial factors and asthma morbidity in inner-city children with asthma.

OBJECTIVE: Children living in the inner city are affected disproportionately by asthma morbidity and mortality. Previous research has shown that behavioral and psychosocial factors affect asthma morbidity in children. The National Cooperative Inner-City Asthma Study investigated the factors that contribute to asthma morbidity among inner-city children. This article examines the relationship between psychosocial factors and asthma morbidity in this population. METHODS: A total of 1528 English- and Spanish-speaking children 4 to 9 years of age with asthma and their primary caretakers were recruited from 8 research centers in 7 metropolitan inner-city areas in the United States. Psychosocial variables were assessed at baseline and included measures of child and caretaker mental health, caretaker's problems with alcohol, life stress, social support, and parenting style. Morbidity measures were evaluated at baseline and at 3-, 6-, and 9-month follow-up intervals. These included number of hospitalizations and unscheduled visits for asthma in the past 3 months and number of days of wheeze and functional status in the previous 2-week period. RESULTS: Of the psychosocial variables assessed, mental health had the strongest relationship to children's asthma morbidity. Children whose caretakers had clinically significant levels of mental health problems were hospitalized for asthma at almost twice the rate as children whose caretakers did not have significant mental health problems. Children with clinically significant behavior problems had significantly more days of wheeze and poorer functional status in the follow-up period. CONCLUSION: Psychosocial factors, particularly the mental health of children and caretakers, are significant factors in predicting asthma morbidity. They may need to be included in intervention programs aimed at decreasing asthma morbidity in inner-city children with asthma in order for these programs to be successful.

Asthma↗
PubMed1999

Pediatric asthma care in the emergency department: measuring the quality of history-taking and discharge planning.

The National Asthma Education and Prevention Program NAEPP Guidelines include recommendations for history-taking and discharge planning during an asthma visit, but there are no tools to measure performance. The objectives of this study were to define and operationalize key elements of history-taking and discharge planning, to develop a tool for measuring these elements, and to evaluate the quality of history-taking and discharge planning in the emergency department (ED) during visits for asthma using the new tool. Expert opinion and extensive literature review were used to develop a 13-item checklist containing items that should be documented during history-taking and provided during discharge planning for an ED visit for an acute asthma exacerbation by children. A convenience sample of 90 pediatric emergency medicine physicians and allergists rated each item in the checklist. The checklist was used to score audiotapes of asthma visits in the ED. Subjects were 154 parents of asthmatic children aged 4-9 years seeking care in nine inner-city EDs affiliated with asthma centers participating in the National Cooperative Inner-City Asthma Study and the physician/providers who delivered care. Seven of the 13 items on the checklist were rated as required to be performed by more than 90% of the allergist/pediatric emergency medicine physicians. Only 10% of the 154 visits included all seven of the highly rated items, whereas 19% of the visits included three or fewer. Only 7 of the 13 items (54%) were performed in more than 50% of the visits, and 4 items were performed in fewer than 25% of visits. Based on expert ratings, the checklist for measuring elements of history-taking and discharge planning during asthma visits appears to have considerable face validity. In the visits studied, the overall performance of these elements was low. Interventions to improve performance on the checklist might lead to improved care for children with asthma who frequent the ED.

Asthma↗
PubMed1998

Dyspepsia in the community is linked to smoking and aspirin use but not to Helicobacter pylori infection.

BACKGROUND: The relationship between Helicobacter pylori infection and symptoms remains controversial. We aimed to determine if an association exists between unexplained dyspepsia (pain or discomfort centered in the upper part of the abdomen) and H pylori. METHODS: A validated questionnaire was completed by 592 healthy blood donors. Helicobacter pylori serologic values (via enzyme-linked immunosorbent assay), blood group status, and Rh status were measured; 4.9% of subjects who had a history of peptic ulcer disease were excluded from the analyses. RESULTS: The prevalence of dyspepsia and no ulcer history was 11% (95% confidence interval [CI], 8.6%-13.8%); 15.4% of subjects with dyspepsia had H pylori while 14.6% of subjects without dyspepsia were infected (P=.90). The mean dyspepsia impact scores (combining frequency and severity) in those with and without H pylori were 4.7 and 5.4, respectively (P=.20). The median H pylori optical density values in dyspepsia vs no dyspepsia were not significantly different (P=.30). Independent risk factors for dyspepsia were the use of aspirin (odds ratio [OR], 2.2; 95% CI, 1.3-3.7) and smoking (OR, 2.1; 95% CI, 1.3-3.6) but not age, sex, marital status, educational level, income, or the use of alcohol, coffee, or nonsteroidal anti-inflammatory drugs. Independent risk factors for H pylori were increasing age (OR, 1.8 per decade; 95% CI, 1.5-2.3), male sex (OR, 2.1; 95% CI, 1.3-3.4), and net family income (OR, 1.8; 95% CI, 1.2-3.3). CONCLUSION: Dyspepsia in the community is linked to smoking and aspirin use, but not to H pylori infection.

Adult↗
PubMed1998

Reported difficulties in access to quality care for children with asthma in the inner city.

OBJECTIVE: To characterize perceived access and barriers to quality health care for asthma among the caregivers of children in the inner city. DESIGN: Multicenter, cross-sectional survey. SETTING: Eight sites in 7 major metropolitan US inner cities. PARTICIPANTS: A systematic sample of children with asthma, aged 4 to 9 years, and their caregivers who resided in census tracts in which at least 30% of the households were below the 1990 federal poverty guidelines, recruited from 25 primary care clinics and 13 emergency departments (EDs) from November 1, 1992, through October 31, 1993. RESULTS: Of the 1528 children enrolled, 1376 had physician-diagnosed asthma and form the basis of this report. This group was further divided into 284 children (20.6%) who met all recruitment criteria for severe asthma and 207 (15.0%) with mild asthma who met none. Of parents in the total sample, 95.6% reported a usual place for short-term asthma care for their child; 75.4% used the ED. Children with severe asthma were significantly more likely to use the ED than those with mild asthma (84.3% vs 63.0%; P<.01). A usual place for follow-up asthma care was reported by 96.7% of subjects. There were no differences in access or type of facility used by asthma severity. More than half the study group reported difficulty in accessing care for acute asthma attacks and for follow-up care with no differences by asthma severity. Among those with severe asthma, 47.5% used inhaled steroids or cromolyn, 52.8% used a spacer device if they had been prescribed a metered dose inhaler, and 21.2% of children older than 6 years were prescribed a peak flowmeter. Patients with mild asthma were significantly less likely to report use of all 3 items (steroids or cromolyn, 1.4%; spacer device, 15.4%; and peak flowmeter, 3.1%, respectively; P<.01). CONCLUSION: Although access to asthma care among children in US inner cities appears adequate as determined by the traditional measure of reporting a regular source of care, barriers are frequently reported, as are deficiencies in the quality of medical care.

Anti-Asthmatic Agents↗
PubMed1998

Differences between false-negative and true-positive Papanicolaou smears on Papnet-assisted review.

This study explored whether there were differences between false-negative and true-positive Papanicolaou (Pap) smears in the number of abnormal images on a Papnet-assisted review. The degree of agreement between cytotechnologists over Papnet tile status (normal/abnormal) was assessed. False-negative and true-positive Pap smears preceding a histologic diagnosis of carcinoma in situ were scanned by Papnet, and the resulting digital images and slides were assessed independently by three cytotechnologists. The median number of abnormal tiles was 7.3 for false-negative slides and 29.7 for true-positive slides. Three-way agreement between cytotechnologists was better for true-positive slides (kappa, 0.60) than for false-negative slides (kappa, 0.47). These results confirm intrinsic differences between false-negative and true-positive Pap smears. The fair to good agreement beyond chance on tile status indicates that a cautious approach should be adopted if digital image review is performed in a judgemental manner.

False Negative Reactions↗
PubMed1998

Relationship of indoor allergen exposure to skin test sensitivity in inner-city children with asthma.

BACKGROUND: It is important to understand the relationship between environmental allergen exposure dose and the risk of atopic individuals becoming sensitized to that allergen if we are to change the risk of sensitization and morbidity from allergic disease. OBJECTIVE: The objective of these studies was to determine whether there was a dose response between current exposure to mite, cockroach, and cat allergen in inner-city children and to determine the prevalence of sensitization to these allergens. METHODS: A sample of 500 children was selected from the 1528 children enrolled in the National Cooperative Inner City Asthma Study. Children were selected who had a sample of home dust and valid skin test responses performed with a MultiTest skin test device. The samples of home dust were collected from the floor and furniture in the kitchen, bedroom, and television/living room and were assayed for Der p 1, Der f 1, Bla g 1, and Fel d 1 allergens. RESULTS: Each allergen level correlated significantly between rooms in individual homes. Mite (Der p 1 and Der f 1) and cat (Fel d 1) allergen levels were frequently below the detection limit of the assay. Cockroach allergen (Bla g 1) concentrations in the child's bedroom were related to the prevalence of positive skin test responses to cockroach allergen extract among the children, with an odds ratio for sensitization of 1.45 (1.11-1.92). Positive skin test responses to cockroach allergen were seen in 15% of children exposed to bedroom dust with a Bla g 1 concentration below the level of detection compared with a rate of 32% in bedrooms with Bla g 1 levels of 1 to 2 U/g and 40% to 44% among those in rooms with 4 U/g or greater. The relationship between exposure and positive skin test responses was clearly stronger among atopic children with a greater number of positive skin test responses. CONCLUSIONS: Despite widespread exposure to household allergens, the strongest relationship between exposure and sensitization was seen in the bedroom. The dose response between exposure to cockroach allergen and sensitization suggested that exposure to low doses of allergen, 2 U/g or less, was a risk factor and that the risk plateaus above 4 U/g. Atopy modified the relationship of exposure to sensitization.

Air Pollution, Indoor↗
PubMed1998

Successful techniques for retention of study participants in an inner-city population.

The purpose of this work was to describe methods of retaining participants in studies of inner-city populations, including the timing and intensity of contacts; and to describe the characteristics of participants who did not complete all follow-up interviews and/or return all peak flow diaries in the National Cooperative Inner-City Asthma Study. A cohort study design was used involving hospital emergency rooms and community clinics in seven major urban areas. Participants included 1337 4- to 9-year-old asthmatic children and their caretakers. Nearly 89% of participants completed 3-, 6-, and 9-month follow-up interviews. The 15% of participants who completed a baseline interview on the weekends were significantly more likely to complete follow-up interviews on a weekend. The percent of follow-up interviews conducted in person increased over time from 5% to 8%. The percent of participants with complete follow-up increased as the number of contact names increased (86% with zero contacts, 91% with two contracts; p = 0.03, test for trend). Participants who required at least four phone calls to complete the 3- and 6-month assessment were significantly more likely to be black, have higher participant stress, and have a smoker in the household (p < 0.05). Multiple logistic regression suggests that higher social support and lower parental stress were both predictors of completed interviews. Within our study sample of inner-city minority participants with asthmatic children, only a small proportion of participants missed any follow-up interviews. Increased caretaker stress, decreased social support, and inability to provide several alternate contacts were all predictive of retention problems. Having a flexible staff, computer tracking, and face-to-face recruitment appear essential to achieving nearly complete follow-up within a population historically difficult to follow.

Asthma↗