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Biomedical subjects

M McDowell

Publications and source records attributed to M McDowell.

At least 19 recordsLinked to original sources
PubMed2006

Tables for the selection of correct blood pressure cuff size based on self-reported height and weight and estimating equations for mid-arm circumference: data from the US National Health and Nutrition Examination Survey.

The purpose of this study was to develop practical prediction equations for estimating adult mid-arm circumference (AC) using self-reported height and weight data from NHANES III 1988-1994 and NHANES 1999-2000. Both surveys used a complex sample design to obtain nationally representative data for the US civilian noninstitutionalized population. The analytic sample consisted of 4801 men and 4854 women in NHANES III and 1960 men and 2180 women from NHANES 1999-2000. Self-reported weight, height, and age data from NHANES III were used for model building, and similar data from NHANES 1999-2000 were used for validation. An all-possible regressions procedure by gender was used to derive the mid-AC prediction equations. The final prediction equations for adult mid-AC are (for self-reported weight in pounds and height in inches) for men: AC (cm) = 32.52145 + 0.10975 x (wt)-0.26057 x (ht)-0.03028 x (age), R2 = 0.76; and for women: AC (cm) = 30.22126 + 0.13534 x (wt)-0.34121 x (ht) + 0.09014 x (age)-0.00082565 x (age2), R2 = 0.81. Based on these equations, tables were created to predict mid-AC using self-reported height and weight. Clinicians can refer to our prediction equations and reference tables to determine mid-AC and proper BP cuff sizes.

Adult↗
PubMed2005

US demographic trends in mid-arm circumference and recommended blood pressure cuffs: 1988-2002.

Mid-arm circumference (AC) measurement is a prerequisite for the selection of properly sized blood pressure (BP) cuffs and accurate BP readings. This study examined trends in the frequency distribution of mid-AC and corresponding recommended BP cuff sizes using National Health and Nutrition Examination Survey (NHANES) III (1988-1994) and NHANES 1999-2002 data. Both surveys used a complex sample design to obtain nationally representative samples of the civilian noninstitutionalized US population. The sample consisted of 7453 men and 8372 women from NHANES III and 4295 men and 4838 women from NHANES 1999-2002. Mean mid-AC (cm) and associated American Heart Association-defined cuff sizes were assessed. Variables were analysed by gender, age, race/ethnicity, and by hypertension or diabetic co-morbidity. Mid-AC increased significantly between surveys for all age groups; the greatest increase in mid-AC occurred in the 20-39 year age group. Data from NHANES 1992-2002 show that among nonHispanic white and nonHispanic black men aged 20-59 years, the mean mid-AC was >34 cm. Among NHB women aged 40 years and above, the mean mid-AC was greater than or equal to 34 cm. In all, 42% of all men and 26% of all women aged 40-59 years required large BP cuffs. In all, 39% of individuals classified as hypertensive and 47% of self-reported diabetics required a BP cuff greater than the standard adult size. In conclusion, mean mid-AC has increased across many demographic subgroups in the US with implications for the accuracy of BP measurement in clinical practice.

Adult↗
PubMed2005

A controlled study on batted ball speed and available pitcher reaction time in slowpitch softball.

OBJECTIVES: To investigate safety risks in slowpitch softball by conducting laboratory and experimental studies on the performance of high tech softball bats with polyurethane softballs. To compare the results with the recommended safety standards. METHODS: ASTM standard compression testing of seven softball models was conducted. Using these seven softball models, bat/ball impact testing was performed using seven adult male softball players and six high tech softball bat models to determine mean batted ball speeds. Over 500 bat/ball impact measurements were recorded and analysed. Available pitcher reaction time was calculated from the mean batted ball speed measurements. RESULTS: According to the United States Specialty Sports Association and the Amateur Softball Association, the maximum initial batted ball speed should be 137.2 km/h, which corresponds to a minimum pitcher reaction time of 0.420 second. These experiments produced mean batted ball speeds of 134.0-159.7 km/h, which correspond to available pitcher reaction times of 0.409-0.361 second. CONCLUSION: The use of high tech softball bats with polyurethane softballs can result in batted ball speeds that exceed the recommended safety limits, which correspond to decreased available pitcher reaction times.

Athletic Injuries↗
PubMed2005

Urinary mercury concentrations associated with dental restorations in adult women aged 16-49 years: United States, 1999-2000.

BACKGROUND: Mercury amalgam dental restorations have been used by dentists since the mid 19th century and issues on safety continue to be periodically debated within the scientific and public health communities. Previous studies have reported a positive association between urine mercury levels and the number of dental amalgams, but this relation has never been described in a nationally representative sample in the United States. AIMS AND METHODS: Using household interview, dietary interview, dental examination, and laboratory data from the 1999-2000 National Health and Nutrition Examination Survey (NHANES), the association between mercury concentrations and dental restorations was examined in US women of reproductive age. RESULTS: In women of childbearing age, approximately 13% of all posterior dental surfaces were restored with amalgams and the average urinary mercury level in women was low (1.34 microg/l). It is estimated that an increase of 1.8 microg/l in the log transformed values for mercury in urine would occur for each 10 dental surfaces restored with amalgam. CONCLUSIONS: Although the findings do not address the important issues of adverse health effects at low thresholds of mercury exposure, they do provide important reference data that should contribute significantly to the ongoing scientific and public health policy debate on the use of dental amalgams in the USA.

Adolescent↗
PubMed2001

Diet interviews of subject pairs: how different persons recall eating the same foods.

OBJECTIVE: To compare qualitative descriptions of the same food items eaten by different persons using 24-hour dietary recall interviews. DESIGN: Eleven pairs of subjects were interviewed twice using 24-hour dietary recalls such that each member of the pair described the same day's foods. Each pair shared a home and ate at least 2 meals together daily. After each interview, subjects were asked to identify the foods reported during the interview that they observed the other member of their pair consuming and to note when a particular food was the only item of that type available in the house. Qualitative descriptions of the foods were compared, differences in descriptions were noted, and calculations were made of the potential energy error produced if a subject erred in reporting a food item. SUBJECTS/SETTING: Subjects were randomly selected from a database of persons who have participated in other studies at the Beltsville Human Nutrition Research Center. Ten pairs were husbands and wives and 1 pair was sisters. Each pair reported eating at least 2 meals per day together. Dietary recall interviews were done at the Research Center and were conducted by a trained dietitian in a quiet room free of distractions. RESULTS: Discrepancies in qualitative food descriptions were identified for every subject pair interviewed. Men were found to be more likely to omit food items than women, snack items were more likely to be omitted than meal items, meat items were likely to be described inaccurately, and first interviews were likely to contain more errors than second interviews. APPLICATIONS/CONCLUSIONS: This analysis shows which types of food items are most likely to be omitted or inaccurately described, and that dietetics professionals may improve the accuracy of dietary intake interviews by asking questions related to meat, milk, and snacks very carefully. The analysis also showed reductions in recall inconsistencies from the first recall to the second recall, suggesting that the learning associated with repeated interviews may be helpful in accurately identifying what a person consumes.

Adult↗
PubMed2000

Personal viewpoint: eclecticism in health services for developmental disorders.

The term 'eclectic', as applied to health care for children with developmental disorders, portrays an individualized, adaptive service response to local constraints and pressures. While this may appear appropriate for the local setting, the end result is a broad diversity of health care approaches. This paper discusses three separate processes that interact at a local level, increasing the likelihood of an eclectic local model of health care for this population of children. The first process draws from the direct clinical work. Variable training, knowledge and skills among health care providers, in combination with differing beliefs around the nature of the problems and their management leads to health care which directly reflects the attributes of the local clinicians. A separate, second process fuelling variability is the differing models of departmental responsibility across Australia - which Government departments fund which aspect of care for children with disabilities. The final process relates to funding streams for health care. State public health, federal Medicare and private insurance all support health services for children with disabilities, with the financial incentives (budgets compared to fee-for-service) driving a divergence of practice. This paper concludes that the external political, administrative and financial frameworks within which health care is constructed will continue to promote clinical eclecticism to a degree that would probably be considered unacceptable in other areas of child health care. The solution can only arise from within the clinical work itself, with greater clarity of understanding around the nature of the disorders, the outcomes for which health care takes responsibility, and an increasing focus on an evidence based set of approaches towards achieving these.

Australia↗
PubMed2000

A 'chronic disorder' health-care model for children with complex developmental disorders.

OBJECTIVES: To conceptualize, develop and evaluate a 'chronic disorder' clinical model of health services for children with 'low-severity' developmental disorders assessed and treated within a public Child Development Unit. METHODOLOGY: Concepts of family empowerment, child resiliency and the management of clinical complexity were explicitly incorporated into the service model and the clinical strategies in order to address long-term goals of prevention and health promotion. To explore the efficacy of this model, a telephone audit survey was conducted of parents of 42 children seen sequentially through this modified service. RESULTS: Parent data indicate a high level of satisfaction with the integrated, individualized assessment processes and effective transmission of information through both written reports and dedicated discussion visits. A treatment methodology based on parent chosen treatment goals for short and long time-frames was experienced as achievable and successful. CONCLUSIONS: These data suggest that the service goals of an integrated team process, parent empowerment and effective clinical collaborations may be achievable from a health care setting. A change in emphasis from remedial treatment to adaptation, health promotion and tertiary prevention is integral to these strategies. The concepts, clinical model and evaluation are presented to stimulate discussion around the question of what child health services are attempting to achieve for children with complex developmental disorders.

Australia↗
PubMed1999

Increased ultraviolet sensitivity and chromosomal instability related to P53 function in the xeroderma pigmentosum variant.

The xeroderma pigmentosum (XP) variant (XPV) is a form of XP that has normal excision repair but shows defective DNA replication after UV irradiation. In developing various transformed fibroblast cell lines from these patients, we have found that there are significant phenotypic changes in transformed cells that seem to correlate with inactivation of p53. After transformation with SV40, XPV cell lines are only slightly UV sensitive, like their primary counterparts, but their sensitization with caffeine and the induction of sister chromatid exchanges (SCEs) by UV irradiation are greatly enhanced. After transformation by HPV16 E7, which targets the retinoblastoma cell cycle regulatory gene, there is no change in the UV sensitivity of XPV cells; but, when transformed by HPV16 E6 or E6 and E7 combined, there is a large increase in UV sensitivity and in the induction of SCEs. These changes are not associated with any detectable changes in the reactivation of an externally irradiated luciferase expression vector, the excision of cyclobutane pyrimidine dimers from bulk DNA, or unscheduled DNA synthesis and, therefore, do not involve excision repair. We suggest that if SCEs represent homologous recombination between sister chromatids, then in the absence of p53 function, the DNA chain arrest typical of UV-damaged XPV cells initiates strand exchange during recovery. In untransformed cells with normal p53, the preferred mode of recovery would then be replication bypass. The symptoms of elevated solar carcinogenesis in XPV patients may, therefore, be associated with increased genomic instability in cells of the skin in which p53 is inactivated by UV-induced mutations.

Caffeine↗
PubMed1999

Isolation of Providencia heimbachae from human feces.

Providencia heimbachae was first described in 1986. It has been isolated from penguin feces and an aborted bovine fetus. To date, there has been no reported isolation of this organism from human specimens. We now report the isolation of P. heimbachae from the stool of a 23-year-old woman with idiopathic diarrhea. The identity of the human strain was determined biochemically and by DNA relatedness to the type strain of P. heimbachae.

Adult↗
PubMed1998

Distribution of mutations in the human xeroderma pigmentosum group A gene and their relationships to the functional regions of the DNA damage recognition protein.

A series of xeroderma pigmentosum group A cell lines from 19 patients and cell lines from 13 other family members were examined for XPA mutations to find previously unidentified mutations from American and European patients, to establish pedigrees in represented families, and to develop a database for XPA diagnosis. Most mutations were deletions and splice site mutations observed previously in other XPA patients, in exon III, intron III, or exon IV, that resulted in frameshifts within the DNA binding region-including an Afl III RFLP (G to C) in four unrelated families. One new mutation was a point mutation within intron III (A to G) creating a new splice acceptor site that may compete with the original splice acceptor site. Missplicing at this new site inserts 11 nucleotides in the mRNA creating a frameshift. A small amount of normal splicing to give wild-type XPA protein is the likely molecular mechanism for the relatively mild clinical features of this patient. In another patient, a new 2 bp deletion in the RPA70 binding region was identified in the same region as a 20 bp deletion previously characterized in an unrelated patient. Mutations in the DNA binding region of XPA were from patients with the more severe disease often associated with neurological complications, whereas mutations in the C-terminal end of the protein, which interacts with the TFIIH transcription factor, were from patients with milder skin disease only. The rarity of naturally occurring missense mutations in the DNA binding region of XPA suggests that amino acid changes might be sufficiently tolerated that patients would have mild symptoms and escape detection.

Alternative Splicing↗
PubMed1995

The economic burden imposed by a residual case of eastern encephalitis.

To estimate the economic burden imposed by eastern encephalitis (EE), we identified a series of residents of eastern Massachusetts who had survived EE infection and enumerated any costs that could be attributed to their experience. The records of three people who suffered only a transient episode of disease were analyzed as well as those of three who suffered severe residual sequelae. Transiently affected subjects mainly required assistance for direct medical services; the average total cost per case was $21,000. Those who suffered persistent sequelae remained at home and seemed likely to live a normal span of years, but without gainful employment. Early in the course of their chronic illness, costs ranged as high as $0.4 million per year, but plateaued at about $0.1 million after three years. Hospital costs, which dominated early in the disease experience, approached $0.3 million per patient. Educational costs tended to replace hospital costs after two years as the dominant economic burden and totaled about $0.3 million per patient during the first six years. Total costs then averaged almost $0.8 million. By the time that these subjects will have reached 22 years of age, disease-related costs will have totaled about $1.5 million. Institutionalization will impose an additional lifetime cost of $1.0 million. Insecticidal interventions designed to avert outbreaks of human EE infection cost between $0.7 million and $1.4 million, depending on the extent of the treated region. The direct costs of an intervention are less than the $3 million imposed on one person suffering residual sequelae of EE.

Adolescent↗
PubMed1994

Mutation and expression of the XPA gene in revertants and hybrids of a xeroderma pigmentosum cell line.

A series of ultraviolet (UV)-resistant cell lines have been generated from a UV-sensitive XP group A cell line homozygous for a stop codon (TGA) in the chromosome 9 XPA gene. Three lines generated by chemical mutagenesis acquired the ability to excise (6-4) photoproducts but not cyclobutane dimers from the whole genome; two lines generated by a fusion procedure with hamster cells acquired the ability to excise both (6-4) photoproducts and cyclobutane dimers from the whole genome. A central region of the hamster XPA gene was cloned and sequenced. With the use of species-specific primers in the polymerase chain reaction, we found that the hybrid cell lines do not contain a hamster XPA gene. Sequence analysis showed that all of the UV-resistant cell lines contain reversions of the human stop codon, resulting in missense mutations (glycine or leucine for arginine) or wild-type sequences. The concentration of XPA protein in revertant cell lines was about one-half that in normal cells, which would be expected from heterozygous cells; there was no evidence that the mutant proteins were less stable than the wild-type proteins. These results are consistent with the idea that the XPA protein initiates repair by binding to damaged sites with various affinities, depending on the photoproduct and the transcriptional state of the region. A concentration of XPA protein near 50% is needed before repair can proceed into nontranscribed regions of the genome. The revertant cell lines represent a class of missense mutations in the XPA gene that may have altered specificity and that can be used to understand some of the regulatory differences in repair of photoproducts in various regions of the genome.

Amino Acid Sequence↗
PubMed1993

The National Health and Nutrition Examination Survey III: describing the health and nutritional status of older Americans.

The National Health and Nutrition Examination III will provide important data for examination of the health and nutritional status of persons in the U.S. Innovations in the study, particularly the inclusion of persons over age 74 and the focus of the survey on the major chronic diseases of old age, will enhance the value for older persons. Response rates for phase 1 (1988-1991) show that about 80% of all older subjects agreed to the interview; examination rates declined with age, but the use of a home examination increased the response rate for those aged 75 or older by about 9% to 67% for men and about 62% for women. Analytic plans include examination of the effect of nutrition on health, as well as the effect of health status on the distribution of nutritional risk factors in old age.

Adult↗
PubMed1990

Immunoglobulin lambda gene rearrangement can precede kappa gene rearrangement.

Immunoglobulin genes are generated during differentiation of B lymphocytes by joining gene segments. A mouse pre-B cell contains a functional immunoglobulin heavy-chain gene, but no light-chain gene. Although there is only one heavy-chain locus, there are two light-chain loci: kappa and lambda. It has been reported that kappa loci in the germ-line configuration are never (in man) or very rarely (in the mouse) present in cells with functionally rearranged lambda-chain genes. Two explanations have been proposed to explain this: (a) the ordered rearrangement theory, which postulates that light-chain gene rearrangement in the pre-B cell is first attempted at the kappa locus, and that only upon failure to produce a functional kappa chain is there an attempt to rearrange the lambda locus; and (b) the stochastic theory, which postulates that rearrangement at the lambda locus proceeds at a rate that is intrinsically much slower than that at the kappa locus. We show here that lambda-chain genes are generated whether or not the kappa locus has lost its germ-line arrangement, a result that is compatible only with the stochastic theory.

Alleles↗
PubMed1988

Looping out and deletion mechanism for the immunoglobulin heavy-chain class switch.

In the mouse pre-B-cell line 18-81, cells can switch production in vitro from immunoglobulin mu chain to gamma 2b chain. The gene encoding the gamma 2b chain is created by a rearrangement of the mu gene. This rearrangement always takes place within a homolog. In cells with a gamma 2b gene, most of the time the gene segment encoding the constant region of the mu chain is deleted, but often the rearrangement leads to cells that produce no immunoglobulin, and all DNA sequences are retained. The latter result is due to an inversion. Inversions exclude the unequal sister chromatid exchange model of the heavy-chain class switch. Looping out is an intermediate step in the process of generating an inversion. Our findings demonstrate that the switch rearrangement occurs by looping out and deletion.

Animals↗
PubMed1987

Personality development following sexual abuse.

Thirty-seven girls and twelve boys who had been sexually abused at an average of 2.6 years previously were traced and reviewed. The nonoffending parents participated in a structured interview and the children were assessed using the Piers-Harris Self-Concept Scale and the Achenbach Child Behavior Checklist. Each child was matched with a child not known to have been sexually abused and these control children underwent a similar psychological assessment. Interviews with the nonoffending parents found that 76% of the children were thought to be less confident than before, 30% had fewer friends, and 20% were more aggressive. Increased sexual awareness was noted in 24%. School teachers reported that 28% still had behavior problems, 17% had repeated a year at school, and a further 17% had deteriorated in their school work. The sexually abused girls had significantly lower self-esteem than the control girls. There was no difference in self-esteem between the control and the sexually abused boys. There was a higher incidence of stranger assault in the boys compared with the girls. The Child Behavior Checklist completed by the parents, the Teacher Report Form, and the Youth Self-Report of the Child Behavior Checklist showed that a highly significant proportion of sexually abused children fell into the clinical range. Sexual abuse appears to have long-term adverse consequences for many of the victims. This may have implications for their ability to relate to others, for the adult friendships they will make, and eventually for the way they will relate to their own children.

Adolescent↗
PubMed1986

Serial studies on the cellular immune response to streptococcal antigens in acute and convalescent rheumatic fever patients in Trinidad.

Acute rheumatic fever (ARF) has the characteristics of an autoimmune disease, triggered by cross-reactive antigens shared by the group A streptococcus and a variety of tissues including the heart, endothelium, and basal ganglia. Using two parameters of cellular reactivity, migration inhibition and blastogenic transformation, ARF patients from Trinidad show significant lymphocyte reactivity to streptococcal antigens, particularly those from an ARF associated streptococcal strain. This reactivity, studied over a 2-year period, peaked at 1 to 6 months after the acute onset and remained significantly elevated for at least 2 years. The reactivity is directed mainly toward a nonionic detergent extractable material in the cell membrane. These studies suggest a possible streptococcal strain specificity in ARF and demonstrate persistent sensitization, which explains the increased susceptibility to recurrences in the 2 years following the acute episode.

Antigens, Bacterial↗