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Biomedical subjects

M Carpenter

Publications and source records attributed to M Carpenter.

At least 37 records · Page 2Linked to original sources
PubMed1996

A canine distemper virus epidemic in Serengeti lions (Panthera leo).

Canine distemper virus (CDV) is thought to have caused several fatal epidemics in canids within the Serengeti-Mara ecosystem of East Africa, affecting silver-backed jackals (Canis mesomelas) and bat-eared foxes (Otocyon megalotis) in 1978 (ref. 1), and African wild dogs (Lycaon pictus) in 1991 (refs 2, 3). The large, closely monitored Serengeti lion population was not affected in these epidemics. However, an epidemic caused by a morbillivirus closely related to CDV emerged abruptly in the lion population of the Serengeti National Park, Tanzania, in early 1994, resulting in fatal neurological disease characterized by grand mal seizures and myoclonus; the lions that died had encephalitis and pneumonia. Here we report the identification of CDV from these lions, and the close phylogenetic relationship between CDV isolates from lions and domestic dogs. By August 1994, 85% of the Serengeti lion population had anti-CDV antibodies, and the epidemic spread north to lions in the Maasai Mara National reserve, Kenya, and uncounted hyaenas, bat-eared foxes, and leopards were also affected.

Amino Acid Sequence↗
PubMed1995

Dietary antioxidants and carotid artery wall thickness. The ARIC Study. Atherosclerosis Risk in Communities Study.

BACKGROUND: Evidence that dietary antioxidants may prevent atherosclerotic disease is growing. The relationship between the intake of dietary and supplemental vitamin C, alpha-tocopherol, and provitamin A carotenoids and average carotid artery wall thickness was studied in 6318 female and 4989 male participants 45 to 64 years old int he Atherosclerosis Risk in Communities Study. METHODS AND RESULTS: Intake was assessed by use of a 66-item semiquantitative food-frequency questionnaire. Carotid artery intima-media wall thickness was measured as an indicator of atherosclerosis at multiple sites with B-mode ultrasound. Among men and women > 55 years old who had not recently begun a special diet, there was a significant inverse relationship between vitamin C intake and average artery wall thickness adjusted for age, body mass index, fasting serum glucose, systolic and diastolic blood pressures, HDL and LDL cholesterol, total caloric intake, cigarette use, race, and education (test for linear trend across quintiles of intake, P = .019 for women and P = .035 for men). An inverse relationship was also seen between wall thickness and alpha-tocopherol intake but was significant only in women (test for linear trend, P = .033 for women and P = .13 for men). There was a significant inverse association between carotene intake and wall thickness in older men (test for linear trend, P = .015), but the association weakened after adjustment for potential confounders. No significant relationships were seen in participants < 55 years old. CONCLUSIONS: These data provide limited support for the hypothesis that dietary vitamin C and alpha-tocopherol may protect against atherosclerotic disease, especially in individuals > 55 years old.

Antioxidants↗
PubMed1995

Precision of office-based blood glucose meters in screening for gestational diabetes.

OBJECTIVE: Is the precision of currently available glucose meters adequate for gestational diabetes screening? STUDY DESIGN: We performed a prospective cohort study of 62 gravid women and compared the precision of three glucose meters to laboratory standard technology. RESULTS: The HemoCue coefficient of variation was sufficiently low in venous whole blood and plasma and capillary whole blood and plasma (3.0%, 1.8%, 2.8%, and 2.3%, respectively) to allow use in gestational diabetes screening. The OneTouch II coefficient of variation was sufficiently low in capillary whole blood (2.7%) to allow use in gestational diabetes screening but was too high in venous whole blood and plasma and in capillary plasma (3.6%, 7.8%, and 5.7%). The ExacTech coefficient of variation was too high in venous or capillary whole blood (5.4% and 8.1%) for use in gestational diabetes screening and does not analyze plasma samples. CONCLUSION: The HemoCue meter in venous and capillary whole blood and plasma and the OneTouch II meter in capillary whole blood have coefficients of variation low enough for gestational diabetes screening.

Analysis of Variance↗
PubMed1994

Expression of mutant p53 protein in hepatocellular carcinoma.

p53 mutations are a common genetic finding in hepatocellular carcinoma from areas of high aflatoxin exposure. Recent small studies have shown that p53 gene mutations may be less common in areas with a low prevalence of hepatocellular carcinoma such as Great Britain. The protein product of mutant p53 can be detected immunohistochemically because of its longer half life in comparison with native protein. This study used a novel monoclonal antibody DO-7, raised against recombinant p53 and effective in routinely processed biopsy specimen tissue, to detect the mutant protein in a series of 45 cases of hepatocellular carcinoma occurring in white subjects resident in the United Kingdom. Focal nuclear labelling was seen in four cases (9%); surrounding cirrhotic tissue in one of these was negative for p53 expression. This study shows that p53 mutations are a rare event in hepatocarcinogenesis in Great Britain, an area of low aflatoxin exposure, and supports the concept of geographical variations in the cause and pathogenesis of hepatocellular carcinoma.

Adult↗
PubMed1993

An update of an epidemiology study at a hydrometallurgical nickel refinery in Fort Saskatchewan, Alberta.

A five-year extension to an ongoing epidemiology study has been undertaken. Mortality information was updated for an additional five years through 1985-1989 for 715 male hydrometallurgical nickel refinery employees who worked at Sherritt Gordon Limited in Fort Saskatchewan, Alberta, during the years 1954 to 1978. Mortality ascertainment was obtained using the Canadian Mortality Data Base, maintained by Statistics Canada, and covered the years 1954 through 1989. Cause-specific mortality analyses were accomplished for males, by age group and calendar year of death, for Canada and the province of Alberta. Total mortality was significantly below expectation (42 observed vs. 70 expected deaths for Canada, and 66 expected for Alberta). Statistically fewer observed deaths were found for circulatory disease while multiple myeloma and lymphoid malignancies demonstrated a statistically significant increase of observed deaths. Specific focus was directed at cancers of the respiratory system because of previous reports linking these conditions with exposure to nickel compounds in some workforces. No deaths due to nasal cavity or paranasal sinus cancer were detected among cohort or study group members. Four lung cancer deaths were found with five deaths expected for Canada and four expected for Alberta. To date, no association between exposure to nickel concentrate or metallic nickel and the subsequent development of respiratory cancer has been found in this study. The hydrometallurgical refinery operation is an enclosed process in contrast to other refinery processes such as pyrometallurgical and electrolytic.

Adolescent↗
PubMed1991

Phosphorylation of caldesmon by p34cdc2 kinase. Identification of phosphorylation sites.

It has recently been shown that caldesmon from non-muscle (Yamashiro, S., Yamakita, Y., Hosoya, H., and Matsumura, F. (1991) Nature 349, 169-172) and smooth muscle cells (Mak, A. S., Watson, M. H., Litwin, C. M. E., and Wang, J. H. (1991) J. Biol. Chem. 266, 6678-6681) can be phosphorylated in vitro by p34cdc2 kinase resulting in the inhibition of caldesmon binding to F-actin and Ca(2+)-calmodulin. In this study, we have identified five phosphorylation sites in smooth muscle caldesmon at Ser582, Ser667, Thr673, Thr696, and Ser702. All the sites bear some resemblance to the S(T)-P-X-X motif recognized by p34cdc2. The preferred site of phosphorylation at Thr673 accounts for about 40% of the total phosphorylation. Four of the sites occur in two pairs of closely spaced sites, Ser667/Thr673 and Thr696/Ser702; phosphorylation of one site in each pair inhibits strongly the phosphorylation of the second site in the same pair, presumably due to the close proximity of the two sites. Similar negative cooperativity in phosphorylation of Ser667 and Thr673 was observed using a 22-residue synthetic peptide containing the two sites. Phosphorylation of Ser667/Thr673 and Thr696/Ser702 account for about 90% of the total level of phosphorylation and these sites are located within the 10-kDa CNBr fragment at the COOH-terminal end of caldesmon known to bind actin and Ca(2+)-calmodulin.

Actins↗
PubMed1990

A standard data collection-package for medical follow-up studies.

A standard method of collecting identifying data for medical follow-up studies has been developed by Statistics Canada. By helping improve health record-keeping, this method has the potential to make it easier to track populations exposed to potentially hazardous agents through lifestyle, work, environmental factors, ecological disasters, or medical treatments. The data collection package, which has been reviewed by expert groups and pilot tested, can reduce costs, save time and result in more comparable data. The package guides the user in developing an easily maintained and accessed database using either the Data Collection Package handbook or the personal computer package option. Part I of this article gives an overview of the new data collection package and how it can be used. Part II gives the background and methodological notes on its development.

Canada↗
PubMed1989

Isolation and characterization of a glycosylated form of beta nerve growth factor in mouse submandibular glands.

In the course of characterizing polyclonal antibodies to beta nerve growth factor (NGF) on immunoblot replicas of sodium dodecyl sulfate gels, we observed a protein (designated C protein) migrating as two bands (14.0 and 13.5 kDa) that copurifies with NGF and reacts strongly with its antibodies. The molecule is detectable in the 7 S, beta, and 2.5 S forms of NGF, accounting in the latter two for approximately 2% of total protein. The C protein can be separated from the A and B chains of beta-NGF on acetic acid-urea gels and on two-dimensional gels but not by isoelectric focusing alone. The molecule has been isolated to near purity on reversed-phase high performance liquid chromatography. Amino acid analyses and sequencing through 49 Edman cycles revealed that the protein preparation is composed of the intact and desoctapeptide (des-(1-8] polypeptide chains and suggested a glycosylation site at Asn-45. Following digestion with N-glycanase, the chains migrated on sodium dodecyl sulfate gels identically with the A and B chains of beta-NGF. Although this was accompanied by some degree of proteolytic degradation, the presence of glucosamine (approximately 4 mol/mol of single chain) was confirmed in acid hydrolysates on the amino acid analyzer. No amino sugars were detected in hydrolysates of the A chain nor was galactosamine recovered in either preparation. Glycosylated NGF promotes neuronal growth and survival in a manner indistinguishable from native 2.5 S NGF when tested in the chick sensory ganglion assay and with rat postnatal sympathetic neurons in a dissociated culture cell survival assay or in a compartmentalized culture growth assay. These studies reveal that NGF can be modified by glycosylation in a manner that does not reduce its biological activity.

Amino Acid Sequence↗
PubMed1988

Ascorbate antagonizes the behavioral effects of amphetamine by a central mechanism.

The behavioral response to amphetamine was monitored in rats that received simultaneous intraventricular infusions of saline or ascorbate. Both groups of animals displayed comparable responses, although ascorbate significantly delayed the onset of amphetamine-induced locomotion and rearing. In rats pretreated with a threshold dose of haloperidol (0.025 mg/kg), virtually all aspects of the amphetamine response were attenuated, and this effect was enhanced by ascorbate. In haloperidol-pretreated rats, ascorbate significantly lowered sniffing and forepaw shuffling throughout the amphetamine response. These results suggest that ascorbate antagonizes dopaminergic transmission by a central mechanism.

Amphetamine↗
PubMed1988

Second-trimester maternal serum alpha-fetoprotein levels in pregnancies associated with gastroschisis and omphalocele.

This population-based study analyzes maternal serum alpha-fetoprotein (MSAFP) distributions for 20 cases of gastroschisis and 13 cases of omphalocele occurring in singleton pregnancies from among 72,782 second-trimester pregnancies in Maine and Rhode Island screened consecutively between January 1, 1979 and February 28, 1987. Median values (and ranges) for the two lesions were 4.1 multiples of the median (0.5-29.8) for omphalocele and 7.0 multiples of the median (3.6-13.5) for gastroschisis. The MSAFP distributions for the two conditions were both log-Gaussian, and the log standard deviation was smaller for gastroschisis than for omphalocele. The MSAFP screening sensitivity was greater for gastroschisis than for omphalocele at any given cutoff, and the overall sensitivity of this screening process for detecting open ventral wall defects will differ, therefore, depending upon the relative proportion of gastroschisis and omphalocele cases that occur in the screened population.

Female↗
PubMed1986

The anti-excitotoxic effects of certain anesthetics, analgesics and sedative-hypnotics.

Various agents were tested for their ability to antagonize the acute excitotoxic action of N-methyl-DL-aspartate (NMA) and kainic acid (KA) on neurons in the in vitro chick embryo retina. The following compounds (in order of descending potencies) were effective in completely blocking the neurotoxic activity of NMA: phencyclidine, ketamine, (+/-)-SKF 10,047, pentazocine, D-aminophosphonovalerate, D-amino-phosphonoheptanoate, D-alpha-aminoadipate, OH-quinoxaline carboxylate, kynurenate, (+/-)-cis-2,3-piperidine dicarboxylate, secobarbital, amobarbital and pentobarbital. The latter 6 agents also protected against KA toxicity but complete protection was observed only from relatively high concentrations. At 20 mM, Mg2+ blocked NMA toxicity but at concentrations up to 30 mM did not block KA toxicity. Compounds that failed to block either NMA or KA toxicity include D- and L-aminophosphonobutyrate, L-glutamic acid diethyl ester, xanthurenate, GABA and taurine. The chick embryo retina is a useful preparation for identifying agents that have either excitotoxic or anti-excitotoxic activity.

Analgesics↗
PubMed1986

Penetrating war injuries of the basal forebrain: neurology and cognition.

We compared the neurologic and cognitive performance of 15 young veterans who suffered unilateral penetrating missile wounds to the basal forebrain 15 years ago in the Vietnam War with uninjured controls and patients with lesions elsewhere in the brain. The subjects performed worse on tests of episodic memory, reasoning, and arithmetic and had more prolonged unconsciousness after injury; but their performance usually compared favorably with that of uninjured controls on tests of intelligence, attention, and language and was not consistent with that of a demented patient. The data suggest that the basal forebrain is functionally related to the reticular formation and to the basal forebrain is functionally related to the reticular formation and to the limbic-hippocampal memory system.

Basal Ganglia↗