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Biomedical subjects

M Carpenter

Publications and source records attributed to M Carpenter.

At least 19 recordsLinked to original sources
PubMed2006

Virtual pulmonary arterioscopy in pulmonary embolic disease.

16 slice multidetector CT provides virtual endoscopic views of the inside of arteries, or any other hollow structures. This is performed non-invasively using post-processing of three-dimensional isotropic image data sets, acquired during standard CT examinations. These virtual endoscopic views are simultaneously correlated with the standard multiplanar reconstructions, with the ability to navigate a virtual camera through the hollow structure under study. Normal and abnormal volume rendered images of the pulmonary arteries are presented in correlation with the multiplanar reformats. The abnormal images show the volume rendered appearances of acute and chronic pulmonary embolic disease. It is also postulated that this technique has a problem solving role in the differential diagnosis of chronic mural emboli from extravascular structures such as adjacent lymph nodes or bronchiolar impaction. This technique may also have a role in medical education, providing clinicians and medical students with interactive three-dimensional representations of disease processes.

Angioscopy↗
PubMed2005

Inhalation delivery of manganese superoxide dismutase-plasmid/liposomes protects the murine lung from irradiation damage.

Intratracheal injection of manganese superoxide dismutase-plasmid/liposome (MnSOD-PL) complexes has been demonstrated to delay the onset and reduce the extent of ionizing irradiation-induced murine pulmonary organizing alveolitis/fibrosis. To facilitate translation of this modality to clinical fractionated radiotherapy, inhalation delivery of MnSOD-PL was developed using an ultrasonic nebulizer. Transgene product was quantitated by immunohistochemical quantitation and pulmonary tissue levels of MnSOD biochemical activity. C57BL/6NHsd female mice demonstrated a plasmid dose-dependent increased expression of MnSOD transgene product over the range of 250 microg-2.5 mg of MnSOD-PL administered over a constant 5 min interval. Delivery of a constant concentration of 500 microg of MnSOD-PL with varying times of administration ranging from 0.5 to 10 min demonstrated optimal MnSOD expression at 5 min. Mice pretreated by inhalation delivery of MnSOD-PL demonstrated significantly improved survival after 20 Gy single fraction irradiation to both lungs compared to LacZ-PL inhalation-treated or irradiated control mice. Mice receiving 10 fractions of 3.5 cGy demonstrated increased pulmonary MnSOD transgene product activity by a protocol of every Monday-Wednesday or daily inhalation of MnSOD-PL. Thus, inhalation radioprotective gene therapy using MnSOD-PL provides a practical and effective method for delivery of lung-specific radioprotection during fractionated radiotherapy protocols in a mouse model.

Administration, Inhalation↗
PubMed2002

Molecular analysis of collagen XVIII reveals novel mutations, presence of a third isoform, and possible genetic heterogeneity in Knobloch syndrome.

Knobloch syndrome (KS) is a rare disease characterized by severe ocular alterations, including vitreoretinal degeneration associated with retinal detachment and occipital scalp defect. The responsible gene, COL18A1, has been mapped to 21q22.3, and, on the basis of the analysis of one family, we have demonstrated that a mutation affecting only one of the three COL18A1 isoforms causes this phenotype. We report here the results of the screening of both the entire coding region and the exon-intron boundaries of the COL18A1 gene (which includes 43 exons), in eight unrelated patients with KS. Besides 20 polymorphic changes, we identified 6 different pathogenic changes in both alleles of five unrelated patients with KS (three compound heterozygotes and two homozygotes). All are truncating mutations leading to deficiency of one or all collagen XVIII isoforms and endostatin. We have verified that, in exon 41, the deletion c3514-3515delCT, found in three unrelated alleles, is embedded in different haplotypes, suggesting that this mutation has occurred more than once. In addition, our results provide evidence of nonallelic genetic heterogeneity in KS. We also show that the longest human isoform (NC11-728) is expressed in several tissues (including the human eye) and that lack of either the short variant or all of the collagen XVIII isoforms causes similar phenotypes but that those patients who lack all forms present more-severe ocular alterations. Despite the small sample size, we found low endostatin plasma levels in those patients with mutations leading to deficiency of all isoforms; in addition, it seems that absence of all collagen XVIII isoforms causes predisposition to epilepsy.

Adolescent↗
PubMed2002

A planned randomized clinical trial of treatment for mild gestational diabetes mellitus.

OBJECTIVE: A planned study is described which will determine whether a benefit exists for the treatment of mild carbohydrate intolerance during pregnancy. METHODS: A randomized clinical trial of women with mild gestational diabetes will compare perinatal outcomes in those receiving diet therapy and insulin as required versus those randomized to no specific treatment. RESULTS: The primary outcome of this study will be a composite of neonatal morbidity in the treatment and control groups. CONCLUSIONS: A randomized treatment trial of mild gestational diabetes mellitus will clarify whether identification and treatment of mild gestational diabetes mellitus reduces perinatal morbidity. This information will aid in selecting appropriate thresholds for the treatment of gestational diabetes mellitus.

Cohort Studies↗
PubMed2001

Why we should eliminate the due date: a truth in jest.

We currently use flawed calculations to set a woman's due date based on menstrual periods to determine gestational age. We use the estimated gestational age to make management decisions based on our patients' individual needs. This principle is in contrast to our patients' use of dating to set an estimated date of confinement. This date is seen as a very specific point in time. Patients and their families plan on that date and become distressed when the expected date is not met. Given that many patients are induced electively, that many will have their delivery dates changed, and that many will have delivery dates adjusted for medical reasons, and most importantly given that dating is inaccurate and unreliable, we propose eliminating the due date. We propose giving patients a calculated assigned week of delivery at 32 weeks. An assigned week of delivery allows for individualization of obstetric care based on the needs of our patients, their support systems, and hospital staffing. We believe an assigned week of delivery will improve obstetric practice and patient satisfaction.

Delivery, Obstetric↗
PubMed2001

Understanding of others' intentions in children with autism.

Many studies have shown that children with autism have difficulty understanding the thoughts and beliefs of other people. However, little research has been conducted on what these children understand about simpler mental states such as intentions. The current study tested the understanding of others' intentions in 2 1/2- to 5-year-old children with autism and a control group of children with other developmental delays. We used Meltzoff's (1995) test of understanding of others' unfulfilled intentions in an imitation context, with an additional "End State" condition. We found no significant between-group differences on any measure involving the understanding of others' intentions. Although within-group patterns suggested that children with autism may have a slightly less complex understanding of others' intentions than do other children, it was clear that any deficits these children showed in this area were not as marked as those they typically show on traditional theory of mind tasks.

Autistic Disorder↗
PubMed2001

Mortality experience among employees at a hydrometallurgical nickel refinery and fertiliser complex in Fort Saskatchewan, Alberta (1954-95).

OBJECTIVE: To study the mortality experience of workers at a hydrometallurgical nickel refinery and fertiliser complex in Fort Saskatchewan, Alberta, Canada. METHODS: A total of 1649 male employees of Sherritt International who worked for at least 12 continuous months during the years 1954 to 1978 at the Fort Saskatchewan, Alberta hydrometallurgical nickel refinery and fertiliser complex were followed up for an additional 17 years. Mortality was ascertained from the Canadian mortality data base maintained by Statistics Canada and covered the years 1954-95. Statistics were analysed with Monson's computer program. RESULTS: Total mortality, when compared with the Canadian population, was significantly below expectation. Fewer deaths were found for circulatory disease, ischaemic heart disease, respiratory disease, neoplasms, digestive cancer, and accidents, poisonings, and violence. Among the 718 men in the group exposed to nickel, there were no deaths due to nasal cavity or paranasal sinus cancer. Fewer deaths were found for all causes, circulatory disease, ischaemic heart disease, neoplasms and digestive cancer. Lower death rates were observed than expected for respiratory malignancies and cancer of the bronchus and lung. CONCLUSION: No association was found in this study between exposure to nickel concentrate or metallic nickel in the hydrometallurgical refining process and the subsequent development of respiratory cancer.

Adult↗
PubMed2001

Comparing viewer and array mental rotations in different planes.

Participants imagined rotating either themselves or an array of objects that surrounded them. Their task was to report on the egocentric position of an item in the array following the imagined rotation. The dependent measures were response latency and number of errors committed. Past research has shown that self-rotation is easier than array rotation. However, we found that imagined egocentric rotations were as difficult to imagine as rotations of the environment when people performed imagined rotations in the midsagittal or coronal plane. The advantages of imagined self-rotations are specific to mental rotations performed in the transverse plane.

Adult↗
PubMed2001

Electrophysiologic correlates of attention versus stimulus competition in young male and female listeners.

The effects of attention and stimulus competition on the late auditory-evoked potential (LAEP) were compared in 10 young males and 10 young females. Listeners attended to discriminably different oddball tonal sequences presented binaurally or monaurally. Peak amplitudes in response to the frequent tones were measured for N1, P2, and early and late N2 (N2e and N21) components of the LAEP Whereas N1 amplitudes increased, the amplitudes of P2 decreased when listeners attended to, rather than ignored, the tones. Competition effects for both N1 and P2 resulted in reduced amplitudes in the presence of contralateral competition. Although findings with N2e and N21 suggested possible attention and competition effects, as well as gender differences, the data were inconsistent and will need further experimental verification. The present findings with the N1 and P2 components provide evidence that different neural processes underlie the attention and competition effects in the human brain.

Adolescent↗
PubMed2000

Electrophysiologic signs of auditory competition in the human brain.

The present project investigated the electrophysiologic effects of auditory competition on components of the late auditory evoked potential (LAEP). A group of 12 young female listeners attended to deviant tones interspersed among frequent tones in one ear while trains of deviant and frequent tones of a different frequency were either present or absent at the opposite ear. Comparison of event-related potential (ERP) waveforms with competition- and attention-related difference waves revealed evidence that the neural effects of competition were not simply a moderation of the effects of selective attention (i.e. the processing negativity). The two difference waves exhibited amplitude peaks that were not mirror-images with respect to polarity. This suggests the existence of a unique underlying neural process that is responsible for the effects of competition on the LAEP.

Acoustic Stimulation↗
PubMed2000

Fibrinogen, other putative markers of inflammation, and weight gain in middle-aged adults--the ARIC study. Atherosclerosis Risk in Communities.

PURPOSE: Weight gain is an important risk factor for the development of the metabolic syndrome, and inflammatory mediators are strongly associated with this syndrome. Our aim was to investigate whether inflammation predicts the development of weight gain in populations. RESEARCH METHODS AND PROCEDURES: We investigated selected markers of inflammation in the prediction of weight gain over an approximately 3-year period in a biethnic cohort of 13,017 men and women, 45 to 64 years of age, using multiple linear and logistic regression modeling. RESULTS: In adjusted models, those in the highest quartile of fibrinogen gained, during the first 3 years of follow-up, an estimated 0.23 kg/year more than those in the lowest quartile (p < 0.001). Adjusted odds of a large (greater than the 90th percentile) weight gain for those in the highest quartile of fibrinogen were 1.65 (95% confidence interval [CI], 1.38 to 1.97) times those in the lowest quartile. Similarly adjusted odds ratios for a large weight gain for those with high levels of white blood cell count, factor VIII, and von Willebrand factor were 1.38 (1.14 to 1.67), 1.28 (1.08 to 1.53), and 1.28 (1.08 to 1.51), respectively. DISCUSSION: Fibrinogen and other putative markers of inflammation predict weight gain in middle-aged adults. Given the known links between the inflammatory response and intermediary metabolism and the methodological strengths of the Atherosclerosis Risk in Communities (ARIC) cohort, these findings, though without immediate clinical applicability, suggest that inflammatory processes play a role in the development of the metabolic syndrome and cardiovascular disease in part through stimulation of weight gain.

Arteriosclerosis↗
PubMed1999

Physical activity and incident hypertension in black and white adults: the Atherosclerosis Risk in Communities Study.

BACKGROUND: The epidemiologic observation that physical activity reduces the risk for hypertension has only been made for white men who self-reported hypertension. This study examined physical activity and clinically determined incident hypertension in black and white men and women of the Atherosclerosis Risk in Communities (ARIC) Study. METHODS: ARIC is a population-based prospective study with four U.S. clinic centers. The present analyses included 7,459 black and white adults 45-65 years of age. Hypertension (systolic/diastolic blood pressure >/= 140/90 mm Hg) was defined by blood pressure measured by a random-zero device or medication use. Physical activity was assessed with the Baecke questionnaire. RESULTS: After adjustment for age, baseline blood pressure, ARIC center, education, body mass index, waist-hip ratio, parental history of hypertension, cigarette smoking, alcohol consumption, and diet, white men in the highest quartile of leisure activity (primarily cycling and walking) had a 34% lower odds of developing hypertension over 6 years compared to the least active (OR = 0.66, 95% CI = 0.47-0.94; P for quartile trend = 0.01). Baseline activity was not associated with incident hypertension in white women or blacks. CONCLUSIONS: Leisure-time physical activity reduces the odds of hypertension in middle-aged white men. Additional studies in women and blacks are needed.

Black or African American↗
PubMed1999

Pneumotonometry versus Goldmann tonometry after laser in situ keratomileusis for myopia.

PURPOSE: To assess the reliability of intraocular pressure (IOP) measurement by Goldmann applanation tonometry (GAT) versus pneumotonometry in patients after laser in situ keratomileusis (LASIK) for myopia. SETTING: Shiley Eye Center, University of California San Diego, La Jolla, California, USA. METHODS: In this prospective study, 31 eyes of 17 patients were evaluated before and 1 month after having LASIK for myopia. A masked observer measured preoperative and postoperative IOP by GAT centrally and by pneumotonometry at the center and the periphery of the cornea. Central corneal thickness and curvature were evaluated. RESULTS: Preoperative IOP showed a good correlation between GAT and pneumotonometry values (r = 0.82). Mean postoperative IOP by GAT was lower by 3.8 mm Hg +/- 2.2 (SD) (26.3% +/- 15.2%) than by pneumotonometry: 2.3 +/- 2.8 mm Hg (15.4% +/- 10.7%) (P = .01). There were no statistically significant differences in central IOP versus peripheral IOP measured by pneumotonometry (P = .4). Regression analysis showed no statistically significant differences in IOP as a function of change in corneal thickness or change in corneal curvature with either device. CONCLUSION: Postoperatively, there was a decrease in IOP measured by central GAT that was statstically significant. Differences in pneumotonometry were less substantial, with greater reliability of pneumotonometry than GAT after LASIK.

Adult↗
PubMed1999

The effects of venting on in-the-ear, in-the-canal, and completely-in-the-canal hearing aid shell frequency responses: real-ear measures.

The acoustic effects of 1-, 2-, and 3-mm vents were investigated with in-the-ear, in-the-canal, and completely-in-the-canal hearing aid shells. Real-ear sound pressure level measures were obtained from unvented and vented shells with 12 adults. In general, with increasing vent size, a statistically significant (p < .05) increase in the amount of low-frequency reduction, an upward shift in vent cutoff frequencies, and an upward shift in vent-associated resonances occurred for all hearing aid shell styles. There was no significant change in the slope of the low-frequency reduction across all hearing aid shell styles (p > .05), albeit the frequency response curves were shifted upward in frequency with increasing vent diameters. Only with the in-the-ear and completely-in-the-canal hearing aid shells were statistically significant (p < .05) differences found with the magnitude of vent-associated resonance as a function of vent diameter, and these differences were not consistent across the different styles. These findings suggest that venting may be used effectively to tune low-frequency responses in custom in-the-ear hearing instruments.

Adult↗
PubMed1999

Surveillance of potential associations between occupations and causes of death in Canada, 1965-91.

OBJECTIVE: To detect unsuspected associations between workplace situations and specific causes of death in Canada. METHODS: An occupational surveillance system was established consisting of a cohort of 457,224 men and 242,196 women employed between 1965 and 1971, constituting about 10% of the labour force in Canada at that time. Mortality between 1965 and 1991 has been determined by computerised record linkage with the Canadian mortality database. Through regression analysis, associations between 670 occupations and 70 specific causes of death were measured. RESULTS: There were almost 116,000 deaths among men and over 26,800 deaths among women. About 28,000 comparisons were made between occupations and specific causes of death. With various reporting criteria, several potential associations were highlighted, including: infectious disease mortality among barbers and hairdressers; laryngeal cancer among male metal fitters and assemblers; lung cancer among female waiters; breast cancer among female metal fitters and assemblers; brain cancer among female nursing assistants and male painters; and ischaemic heart disease among female inspectors and foremen and among male taxi drivers and chauffeurs. CONCLUSIONS: When excess risk of mortality is apparent, the intention of this occupational surveillance system is to spark further studies to gain aetiological knowledge.

Adult↗
PubMed1998

Social cognition, joint attention, and communicative competence from 9 to 15 months of age.

At around 1 year of age, human infants display a number of new behaviors that seem to indicate a newly emerging understanding of other persons as intentional beings whose attention to outside objects may be shared, followed into, and directed in various ways. These behaviors have mostly been studied separately. In the current study, we investigated the most important of these behaviors together as they emerged in a single group of 24 infants between 9 and 15 months of age. At each of seven monthly visits, we measured joint attentional engagement, gaze and point following, imitation of two different kinds of actions on objects, imperative and declarative gestures, and comprehension and production of language. We also measured several nonsocial-cognitive skills as a point of comparison. We report two studies. The focus of the first study was the initial emergence of infants' social-cognitive skills and how these skills are related to one another developmentally. We found a reliable pattern of emergence: Infants progressed from sharing to following to directing others' attention and behavior. The nonsocial skills did not emerge predictably in this developmental sequence. Furthermore, correlational analyses showed that the ages of emergence of all pairs of the social-cognitive skills or their components were inter-related. The focus of the second study was the social interaction of infants and their mothers, especially with regard to their skills of joint attentional engagement (including mothers' use of language to follow into or direct infants' attention) and how these skills related to infants' early communicative competence. Our measures of communicative competence included not only language production, as in previous studies, but also language comprehension and gesture production. It was found that two measures--the amount of time infants spent in joint engagement with their mothers and the degree to which mothers used language that followed into their infant's focus of attention--predicted infants' earliest skills of gestural and linguistic communication. Results of the two studies are discussed in terms of their implications for theories of social-cognitive development, for theories of language development, and for theories of the process by means of which human children become fully participating members of the cultural activities and processes into which they are born.

Attention↗
PubMed1997

Indicators of abuse or neglect in preschool children's drawings.

1. Research designed to examine the systematic ability of children's drawings to disclose abuse or neglect has been equivocal. 2. The use of art to understand preschool-aged children is particularly advantageous because very young children usually are not able to communicate their feelings clearly. 3. The study shows that the family drawings of abused or neglected preschool children can be differentiated from those of children not identified as abused or neglected.

Art Therapy↗