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Biomedical subjects

M A Carpenter

Publications and source records attributed to M A Carpenter.

At least 19 recordsLinked to original sources
PubMed2004

All-optical hydrogen-sensing materials based on tailored palladium alloy thin films.

Optical reflectance measurements were performed to determine the hydrogen response characteristics of 20-nm-thick Pd-Au (Ag) films. The response characteristics displayed a strong dependence on alpha, mixed alpha/beta, and beta Pd-hydride phases formed in the films. The response time peaks in the alpha --> beta phase transition region (1625 s at 0.4% H(2) for Pd(0.94)Ag(0.06) and 405 s at 1% H(2) for Pd(0.94)Au(0.06)), consistent with critical slowing down phenomena. The alpha --> beta phase transition region was shifted and inhibited by changing the alloy element to Au and increasing its corresponding content to 40 atom %, respectively. Initial hydrogen uptake rate measurements determined that, due to the adsorption of ambient background gases, the rate-limiting step for alpha or beta phase PdH formation is dissociative chemisorption of hydrogen for each palladium alloy film. By tuning the alloy content and composition of the palladium films, the surface properties of the film become more receptive toward the rapid detection of hydrogen and a novel hydrogen-sensing material using Pd alloyed with 40 atom % Au is presented.

Journal Article↗
PubMed1999

Bilateral thalamic stimulation for the treatment of essential tremor.

OBJECTIVE: To determine the safety and efficacy of bilateral thalamic stimulation in the treatment of essential tremor (ET). METHODS: Nine ET patients with disabling tremor refractory to pharmacotherapy underwent bilateral staged implants. Tremor was assessed by the Fahn-Tolosa-Marin Tremor Rating Scale at baseline 1 (before first implant), baseline 2 (before second implant), and at 6-month and 1-year follow-up. Blinded evaluations were performed at 3 months. Associated changes in speech were evaluated in six patients. There were seven men and two women with a mean age of 73.8 years. RESULTS: There was a significant improvement in the mean total tremor score from a baseline of 66.1+/-11.6 to 28.4+/-12.8 12 months after the second surgery. Similarly, the mean motor tremor subscore was 20.1+/-5.0 before the first surgery and improved significantly to 14.1+/-3.6 before the second surgery. Motor tremor scores 6 months after the second surgery (6.0+/-3.7) and 12 months after the second surgery (7.5+/-3.9) also improved significantly relative to the preoperative scores. The mean activities of daily living (ADL) subscore at baseline was 18.2+/-2.9 and improved significantly before the second surgery to 9.0+/-3.2. These ADL scores further improved 6 months (6.2+/-5.2) and 12 months (7.9+/-5.7) following the second surgery, but these gains were not significant. Blinded evaluations also revealed a similar degree of improvement. Complications were noted in five patients: asymptomatic intracranial hematoma (1), postoperative seizures (1), a hematoma over the implanted pulse generator (IPG) (1), lead repositioning (1), and IPG malfunction (1). Adverse effects related to stimulation were mild and resolved with adjustment of the stimulation parameters. Three of the six patients demonstrated worsening of dysarthria with both stimulators on. CONCLUSIONS: Bilateral thalamic stimulation is effective in reducing tremor and functional disability in ET; however, dysarthria is a possible complication.

Activities of Daily Living↗
PubMed1999

Demographic and anthropometric correlates of maximum inspiratory pressure: The Atherosclerosis Risk in Communities Study.

Maximum inspiratory pressure (MIP), an indicator of inspiratory muscle strength, is reported on 13,005 African-American and white participants from the Atherosclerosis Risk in Communities Study. Sex-specific associations between MIP and age, anthropometric measures, physical activity, health status, smoking status, and education level are presented. In this cohort of subjects 47 to 68 yr of age, MIP decreased 0.93 cm H2O (p </= 0.0001) in women and 1.2 cm H2O (p </= 0.0001) in men for each 1-yr increase in age. In both sexes, after adjusting for age, the associations between MIP and current body weight, weight at 25 yr of age, waist girth, body mass index, and calf girth were statistically significant and nonlinear (convex quadratic). MIP was positively associated with standing height in both sexes after controlling for age (p </= 0.03). The age-adjusted association between MIP and sitting height was nonlinear in men and linear in women. MIP was also associated (positively) with education level, health status, physical activity, and (negatively) cigarette smoking. The study was not designed to evaluate associations with race, but data patterns suggest the absence of a race effect on MIP.

Aged↗
PubMed1999

Speech sample effects on pressure and flow measures in children with normal or abnormal velopharyngeal function.

OBJECTIVE: This study examined the effect of certain test phoneme contexts on oral pressure and nasal flow values in young children with normal velopharyngeal (VP) function. Comparison was made with responses from children with abnormal function. SPEAKERS: Ten children judged to have normal VP function (mean age = 5.2 years) and five children with VP incompetence (mean age = 7.8 years) were evaluated. Both groups were able to produce the speech sample with standard articulatory postures. Subjects were from the local community and a university cleft palate clinic. DESIGN: Simultaneous oral pressure and nasal flow recordings were obtained from the speakers as they produced /p/ in speech stimuli that varied in terms of test phoneme position in the syllable (releasing and arresting), adjacent vowel height (high, middle, and low), or adjacent consonant characteristics (voicing, placement, and manner). Within-subject differences in pressure and flow were examined to evaluate specific stimulus contrasts in each speaker group. SETTING: Data were collected in the Speech Physiology Laboratory in the Hearing and Speech Department at the University of Kansas Medical Center. RESULTS: There were few speech sample effects on oral pressure for children with VP competence. Nasal flow for this group occurred infrequently but was present at least once in 80% of the subjects. The speakers with VP incompetence demonstrated predictable phoneme context effects (higher flow and lower pressure for a nasal context; higher flow for a high vowel context). CONCLUSION: The finding of no significant stimulus effects for the normal speakers suggests the need for little concern when choosing stimuli for normative study of oral pressure. However, certain stimulus contexts should be considered for data collection if results are to be applied to children with abnormal velopharyngeal function.

Acoustic Stimulation↗
PubMed1998

Phylogeographic patterns of feline immunodeficiency virus genetic diversity in the domestic cat.

Feline immunodeficiency virus (FIV) has a worldwide distribution among feral and domesticated cats and in many cases induces immunodeficiency disease analogous to that of human acquired immune deficiency syndrome. FIV is genetically homologous to human immunodeficiency virus (HIV) in both genome organization and gene sequence and, like HIV, exhibits enormous sequence variation throughout the range of host species. We sampled 91 feral cats from six disparate locales and studied the phylogenetic relationships of viral DNA from infected cats using both pol and env genes (520 and 684 bp, respectively). The patterns from the two genes recapitulated previously described major FIV clades and showed concordance between phylogenetic patterns of the pol and env genes. Evidence for recombination between the pol and env genes was not found among a sampling of nine isolates, although evidence for intragenic exchange within the env gene was observed in two isolates. A small local population of cats from a rural farm in the United Kingdom had a remarkably high FIV antibody prevalence (47%), but displayed 8-fold less overall diversity of FIV genomic variation compared with FIV from different parts of the world. We interpret this low variation as a consequence of a recent monophyletic introduction of FIV into the population.

Animals↗
PubMed1998

Genetic characterization of canine distemper virus in Serengeti carnivores.

The lion (Panthera leo) population in the Serengeti ecosystem was recently afflicted by a fatal epidemic involving neurological disease, encephalitis and pneumonia. The cause was identified as canine distemper virus (CDV). Several other species in the Serengeti were also affected. This report presents CDV H and P gene sequences isolated from Serengeti lions (Panthera leo), spotted hyenas (Crocuta crocuta), bat-eared fox (Otocyon megalotis) and domestic dog (Canis familiaris). Sequence analyses demonstrated that the four Serengeti species carry closely related CDV isolates which are genetically distinct from other CDV isolates from various species and locations. The results are consistent with the conclusions that: (1) a particularly virulent strain of CDV emerged among Serengeti carnivores within the last few years; (2) that strain has recognizable shared-derived (synapomorphic) genetic differences in both H and P genes when compared to CDV from other parts of the world; and (3) that the CDV strain has frequently crossed host species among Serengeti carnivores.

Africa↗
PubMed1998

Reduction in voice tremor under thalamic stimulation.

We studied the effect of deep brain stimulation (DBS) of the ventral intermediate thalamic nucleus on voice symptoms in seven patients with essential tremor. All had undergone DBS for management of hand tremor. Five of the patients had received unilateral implants; two were treated bilaterally. Each reported improvement in hand tremor with thalamic stimulation (a 1-to-3-point change on a 5-point severity scale). Voice tremor was evaluated with and without stimulation using patient and clinician severity ratings, and acoustic measures (rate and amplitude). Four of the seven patients showed reductions in voice symptoms in at least two of these measures, although degree of change differed (e.g., from 1 to 3 points on the 5-point severity scale). Voice gains typically were restricted to those patients with the more severe symptoms and did not parallel improvements in the upper extremities. It appears that reduced voice tremor may be an additional benefit of DBS for some individuals.

Aged↗
PubMed1996

Genetic and phylogenetic divergence of feline immunodeficiency virus in the puma (Puma concolor).

Feline immunodeficiency virus (FIV) is a lentivirus which causes an AIDS-like disease in domestic cats (Felis catus). A number of other felid species, including the puma (Puma concolor), carry a virus closely related to domestic cat FIV. Serological testing revealed the presence of antibodies to FIV in 22% of 434 samples from throughout the geographic range of the puma. FIV-Pco pol gene sequences isolated from pumas revealed extensive sequence diversity, greater than has been documented in the domestic cat. The puma sequences formed two highly divergent groups, analogous to the clades which have been defined for domestic cat and lion (Panthera leo) FIV. The puma clade A was made up of samples from Florida and California, whereas clade B consisted of samples from other parts of North America, Central America, and Brazil. The difference between these two groups was as great as that reported among three lion FIV clades. Within puma clades, sequence variation is large, comparable to between-clade differences seen for domestic cat clades, allowing recognition of 15 phylogenetic lineages (subclades) among puma FIV-Pco. Large sequence divergence among isolates, nearly complete species monophyly, and widespread geographic distribution suggest that FIV-Pco has evolved within the puma species for a long period. The sequence data provided evidence for vertical transmission of FIV-Pco from mothers to their kittens, for coinfection of individuals by two different viral strains, and for cross-species transmission of FIV from a domestic cat to a puma. These factors may all be important for understanding the epidemiology and natural history of FIV in the puma.

Amino Acid Sequence↗
PubMed1995

Association of the waist-to-hip ratio is different with wine than with beer or hard liquor consumption. Atherosclerosis Risk in Communities Study Investigators.

Specific alcoholic beverage associations with the waist-to-hip ratio were characterized in 12,145 African-American and white men and women ages 45-64 years. Estimated waist-to-hip ratios of those consuming more than six nonwine alcohol drinks/week and more than six wine drinks/week (vs. nondrinkers) were 0.007 larger (p < 0.001) and 0.009 smaller (p < 0.05), respectively. In similar comparisons, the odds ratios for a large waist-to-hip ratio were 1.4 (95% confidence interval 1.1-1.7) for nonwine and 0.45 (95% confidence interval 0.21-0.95) for wine intake. The opposite direction in adjusted associations for wine and nonwine (mainly beer) drinking supports the popular concept of the "beer belly."

Adipose Tissue↗
PubMed1995

Thirteen loci physically assigned to sheep chromosome 2 by cell hybrid analysis and in situ hybridization.

Sheep x hamster cell hybrids containing sheep metacentric Chromosome (Chr) 2 were produced by fusing blood leukocytes from normal sheep with hamster auxotrophic Ade F-minus mutants. Cell clones that were isocitrate dehydrogenase 1 (IDH1) positive were cytogenetically characterized, confirming that they contained sheep Chr 2. The following loci were newly assigned by Southern hybridization to sheep Chr 2: lipoprotein lipase (LPL), glycoprotein-4-beta galactosyltransferase 2 (GGTB2), neurofilament light polypeptide (68 kDa; NEFL), surfactant-associated protein 2 (SFTP2), lymphocyte-specific protein tyrosine kinase (LCK), and nebulin (NEB). These new assignments and the in situ localization of gelsolin (GSN) to sheep Chr 2pter-p24 are consistent with the predicted homology of cattle Chr 8 (U18) with sheep Chr 2p, and of cattle Chr 2 (U17) with sheep 2q. In addition, the assignment by cell hybrid analysis of loci previously mapped to Chr 2 in sheep, viz., cholinergic receptor, nicotinic, delta polypeptide (CHRND), collagen type III alpha 1 (COL3A1), fibronectin 1 (FN1), isocitrate dehydrogenase (IDH1), and villin 1 (VIL1), confirmed the localization of sheep syntenic group U11 to this chromosome. By nutritional selection and complementation of the hamster auxotrophic Ade F mutation, the multifunctional enzyme locus phosphoribosylaminoimidazolecarboxamide formyltransferase (AICAR transformylase)/IMP cyclohydrolase (inosinicase) (provisionally given the symbol PRACFT) has also been newly assigned to sheep Chr 2. This report significantly extends the number of loci physically mapped to sheep Chr 2 and confirms its close homology with cattle Chrs 2 and 8.

Animals↗
PubMed1995

Coadaptation and immunodeficiency virus: lessons from the Felidae.

The emergence of pathogenic viruses in new species offers an unusual opportunity to monitor the coadaptation of viruses and their hosts in a dynamic ongoing process of intense biological selection. Tracking lentivirus epidemics in man, monkeys and cats reveals genomic struggles at three levels: quasispecies divergence within an individual; coadaptation of virus and host genomes subsequent to disease outbreaks; and transmission, spread and pathogenesis in related host species. Aspects of each level are revealed by examining the genetic diversity of feline immunodeficiency virus in domestic and wild cat species. This approach has been facilitated by the recent genetic characterization of a novel lentivirus in lions.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Correlates of body fat distribution. Variation across categories of race, sex, and body mass in the atherosclerosis risk in communities study. The Atherosclerosis Risk in communities (ARIC) Study Investigators.

Though central adiposity is a strong, independent risk factor for cardiovascular and all-cause mortality, relatively little is known about its determinants. To characterize the association of central adiposity with several of its possible determinants, while describing variability in these associations across sex, race, and level of body mass index, we conducted a cross-sectional survey of 15,800 white and African-American men and women ages 45 to 64 years participating in the Atherosclerosis Risk in Communities baseline survey, 1987 to 1989. After adjustment for other possible determinants, African Americans had markedly larger subscapular skinfold thickness and subscapular/triceps ratios than did whites, while whites had larger waist/hip ratios. Large, statistically significant variations in waist/hip ratio associations with age, percent of weight gained after age 25, smoking, and physical activity in the workplace existed across categories of sex, race, and body mass index. Based on our findings, we concluded that major variation exists in the waist/hip ratio and in its associations with its possible determinants across categories of race, sex and obesity.

Adipose Tissue↗
PubMed1995

Reliability of body fat distribution measurements. The ARIC Study baseline cohort results. Atherosclerosis Risk in Communities Study.

OBJECTIVE: To estimate the reliability of skinfold and girth measurements, and ratios involving these measurements, commonly used in epidemiological and clinical studies as measures of body fat distribution. DESIGN: Repeated measurements of body fat distribution measures were scheduled on randomly selected participants at the baseline clinical examination of the ARIC Cohort Study, by the same or by different technicians. SETTING: Probability sample of 45-65 year old residents selected from four US communities. MEASUREMENTS: Subscapular and triceps skinfolds were taken twice using a Lange caliper on standardized right-side locations. Waist and hip girths were measured using an anthropometric tape applied at the level of umbilicus and of the maximal protrusion of the gluteal muscles, respectively. Repeated measurements were taken 1-2 h apart. RESULTS: Inter-technician measurements of triceps skinfolds, subscapular skinfolds, waist girth, hip girth, and waist/hip ratio each had high reliability (R > 0.91). The reliability coefficient for triceps/subscapular ratio (R = 0.81) was somewhat lower. For skinfold measures, intra-observer coefficient of variations are lower than the ones observed in previous studies, and inter-technician coefficient of variations are comparable. CONCLUSIONS: These results confirm previous findings which indicate that the reliability of girth measurements is greater than for skinfold measurements. As a consequence, the waist to hip ratio is less affected by measurement error than the skinfold ratio. Moreover, the expected gain in reliability from using the average of two skinfold measures, taken in succession, was not realized, indicating that when measurements are taken in rapid succession by the same technician, statistical independence between measures is questionable.

Analysis of Variance↗
PubMed1994

Dietary fat intake and carotid artery wall thickness: the Atherosclerosis Risk in Communities (ARIC) Study.

Associations between atherosclerosis and dietary fat and cholesterol have been demonstrated in numerous animal experiments. The relation between these dietary components and atherosclerosis has not previously been reported in a population-based study among human beings. The associations of dietary fat and cholesterol with carotid artery wall thickness (atherosclerosis) were investigated in a population-based study, the Atherosclerosis Risk in Communities (ARIC) Study, from 1987 to 1989. Participants were 2,095 black women, 5,146 white women, 1,318 black men and 4,589 white men, aged 45-64 years, recruited from four US communities: Jackson, Mississippi; Forsyth County, North Carolina; Washington County, Maryland; and Minneapolis, Minnesota. Habitual diet was assessed with a food frequency questionnaire. Wall thickness was measured with B-mode ultrasound. After adjustment for age and energy intake, animal fat, saturated fat, monounsaturated fat, cholesterol, and Keys' score were positively related to wall thickness, while vegetable fat and polyunsaturated fat were inversely related to wall thickness. These associations persisted after further adjustment for smoking and hypertension and were consistent across the four race and sex groups. Thus, elements of habitual dietary intake were consistently associated with carotid artery wall thickness, compatible with their putatively atherogenic and antiatherogenic properties.

Black or African American↗
PubMed1994

Dietary intake patterns and sociodemographic factors in the atherosclerosis risk in communities study. ARIC Study Investigators.

BACKGROUND: Comprehensive and up-to-date data on differences in dietary intake according to various sociodemographic factors are needed to understand the potential impact of dietary factors on disease risks in the United States. METHODS: Usual dietary intake assessed by a food frequency questionnaire was examined in relation to race, sex, and educational attainment using baseline data obtained from randomly selected samples of 15,800 middle-aged black and white men and women who participated in the Atherosclerosis Risk in Communities Study. RESULTS: In almost all comparisons, higher educational attainment was associated with recommended dietary intake patterns--lower per energy intakes of meats, eggs, chicken with skin, and whole milk and higher intakes of fruits, vegetables, fish, chicken without skin, and low-fat milk. As expected from these food intake patterns, higher educational attainment was associated with lower intakes of saturated fatty acid and cholesterol and with higher intakes of dietary fiber and various micronutrients. Compared with women's diets, men's diets were slightly more atherogenic (in whites only) based upon Keys score and had lower micronutrient levels. Although there were large differences in the food intakes between blacks and whites, the differences in nutrient intakes were generally smaller. However, intakes of cholesterol and vitamin A were somewhat higher and intakes of saturated fatty acid, calcium, and potassium were lower among blacks than in whites. CONCLUSIONS: This community-based study clearly demonstrated that regardless of race and sex, high educational attainment is associated with recommended dietary intake patterns. Continuing efforts to improve general educational level and to promote healthy dietary habits among those with low socioeconomic status are warranted.

Black or African American↗
PubMed1994

Polymorphism in the coding sequence of the horse transferrin gene.

Transferrin, the iron transport protein of the blood, is highly polymorphic in many species, including the horse. A number of sequence polymorphisms that distinguish several of the variants of horse transferrin are reported here. Previous studies indicated that exons 12 and 15 were likely to be polymorphic. Sequencing regions of exons 12 and 15 from D and R variants revealed 10 nucleotide substitutions that encoded six amino acid replacements. The F1, F2, H2, and * variants were identical to D, and the O variant was almost identical to R, in the regions studied. The data indicated that the horse transferrin variants make up two distinct groups. The positions of differences between the D and F1 alleles were determined by analyzing single-stranded conformation polymorphisms. Sequencing then revealed three nucleotide substitutions, two of which encoded amino acid substitutions. Location of the eight polymorphic residues on the three-dimensional structure of human lactoferrin revealed that all were clustered at one end of the C-lobe.

Amino Acid Sequence↗