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Biomedical subjects

M Cox

Publications and source records attributed to M Cox.

At least 109 records · Page 6Linked to original sources
PubMed1991

Minipump clorgyline administration and CSF amine metabolites in unrestrained monkeys.

The irreversible MAO-A inhibitor clorgyline was administered in doses of 0.5 mg/kg (N = 1), 1 mg/kg (N = 3), and 2 mg/kg (N = 1) to 5 young (age 5.5 to 23.9 months) pigtail (M. nemestrina) monkeys using a 28-day (Alza 2ML4) osmotic minipump. CSF MHPG, 5-HIAA, HVA, and plasma MHPG were measured before and at approximately weekly intervals after pump implantation. Implants were well tolerated. CSF MHPG decreased about 75%, 5-HIAA 30%, and HVA from 30-50% with a tendency to plateau by the second week. Plasma MHPG decreased to undetectable levels. The findings demonstrate that long-term inhibition of MAO-A can be produced in unrestrained monkeys by minipump administered clorgyline. There is an apparently greater effect on the norepinephrine system relative to the serotonin and dopamine systems.

Animals↗
PubMed1991

Human papillomavirus type 16 DNA in an odontogenic keratocyst.

DNA was extracted from an odontogenic keratocyst and assayed for the presence of human papilloma virus (HPV) type 16 DNA sequences using high stringency Southern blot hybridization. HPV type 16 homologous DNA sequences were detected at a copy number of 50-100 genome copies per diploid cell. The oral HPV DNA was not identical to the prototype HPV 16 when cleaved with the restriction enzyme Pst-I, since it appeared to lack the Pst-I C fragment (L2/L1 ORFs) and contained "off-sized" high molecular weight fragments suggestive of integration events into the host cell chromosome.

Aged↗
PubMed1991

Relationship of the aldosterone-induced protein, GP70, to the conductive Na+ channel.

Although one of the primary effects of aldosterone is to increase apical membrane Na+ conductance, as yet none of the proteins induced by the hormone in renal epithelia have been shown to be related to the conductive Na+ channel. Because the toad urinary bladder aldosterone-induced glycoprotein, GP70, has recently been localized to the apical surface of this Na+ transporting epithelium, whether GP70 is associated with the Na+ channel was examined. The specificities of a monoclonal antibody used to characterize GP70 (mAb 20) and a polyclonal antibody raised against the purified bovine renal papillary Na+ channel (anti-CH) were compared: GP70 was specifically immunoprecipitated by both mAb 20 and anti-CH. Moreover, the sodium dodecyl sulfate-polyacrylamide gel electrophoresis profile of mAb 20 purified toad urinary bladder membrane preparations was similar to those reported for bovine and A6 cell Na+ channels. Under nonreducing conditions, a single, very large protein was evident; reduction yielded GP70, a 140-kd polypeptide, and a number of minor bands. Interestingly, only GP70 was induced by aldosterone. Thus, GP70 appears to be associated with the toad urinary bladder conductive Na+ channel; whether GP70 is an integral subunit of the channel or whether it functions as a regulatory moiety remains to be determined. Whatever the case, because GP70 is induced by aldosterone, it likely has a central role in Na+ channel modulation.

Aldosterone↗
PubMed1991

A study of the sensitivity and specificity of four presumptive tests for blood.

The purpose of this work was to conduct a comparative study of the sensitivity and specificity of phenolphthalein, tetramethylbenzidine, leucomalachite green, and orthotolidine as presumptive tests for blood. The findings of this study indicate that the phenolphthalein and the leucomalachite green tests are the most specific and that the tetramethylbenzidine and orthotolidine tests are the most sensitive of the group. The author concludes that the phenolphthalein test is the best single test for evaluating suspected bloodstains.

Aniline Compounds↗
PubMed1991

Impact of very low birth weight infants on the family and its relationship to parental attitudes.

This study tested common assumptions that very low birth weight (VLBW) infants (less than 1500 g) adversely affected families and that if affected parents could choose again, they would prefer not to save potentially handicapped VLBW infants. A survey of parents, which used a validated impact-on-family questionnaire, was sent to families of all 144 traceable VLBW infants (72.2% response), and families of 25 randomly selected healthy term infants (60% response), born in Newfoundland between 1983 and 1987 (median age 36.5 months, range 12 to 71 months). This revealed that families with developmentally delayed VLBW infants perceived no worse impact on the family than those with healthy term infants. Families with developmentally normal VLBW infants perceived a more positive family impact than the other two groups (P less than .05). Most parents of both VLBW and healthy term infants supported saving all infants regardless of outcome (greater than 80%), believed that parents should be the principal decision makers regarding treatment decisions (greater than 92%), and supported the role of physicians (greater than 59%), but not nurses, ethics committees, or other regulatory bodies, in this decision. For the VLBW group, parental attitudes toward saving VLBW infants were related to their perceptions of family impact (P less than .05) but independent of sociodemographic factors or of the developmental normality of the infant. It is concluded that VLBW infants did not adversely affect these Newfoundland families or change their attitudes toward saving potentially handicapped infants. In the current debate about whether VLBW infants should be saved, cognizance must be taken of parental desires.

Adult↗
PubMed1991

Comparison of the attitudes of health care professionals and parents toward active treatment of very low birth weight infants.

Although pediatricians and neonatal nurses influence parents' treatment decisions, little is known about their attitudes toward active treatment of very low birth weight (VLBW) infants (less than 1500 g) and how they compare with parental attitudes. A survey of all 50 pediatricians in Newfoundland (72% response), all 53 neonatal intensive care nurses at the Janeway Child Health Centre (73.6% response), parents of all 144 traceable VLBW infants (72.2% response), and parents of 25 randomly selected normal term infants (60% response), born in Newfoundland between 1983 and 1987, revealed significant differences in attitudes among parents, nurses, and pediatricians about whether active treatment should be offered to potentially severely handicapped VLBW infants. Most parents of both VLBW and normal term infants (greater than 80%) agreed, pediatricians were divided, whereas most nurses (79.5%) objected. Both pediatricians and nurses tended to overestimate (P less than .05) the morbidity, mortality, and costs of care of VLBW infants. There was a direct correlation (P less than .05) between a negative attitude toward saving VLBW infants and a negatively false perception of neonatal morbidity, mortality, and costs. All groups favored a role for parents and physicians in treatment decisions and objected to a role for regulatory bodies. Pediatricians and nurses also favored a role for nurses and hospital ethics committees but parents disagreed. While most nurses (71%) believed it was unethical to save potentially severely handicapped infants, few pediatricians (36.9%) agreed. Only 27.8% of pediatricians and 10.3% of nurses would seek court intervention if they disagreed with a parental decision not to actively treat a potentially handicapped infant.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Iron status of very-low-birth-weight infants during the first 15 months of infancy.

The adequacy of iron stores in infants of very low birth weight (defined as less than 1500 g) in Canada is unknown. We monitored the iron status of 81 such infants at 3, 6, 9, 12 and 15 months of age. All of the infants were fed formula fortified with iron (13 mg/L) for at least 6 months, starting at 2 months of age. The plasma ferritin level decreased after the formula was no longer used. Although 90% of the infants were given cereal fortified with iron (30 mg of iron per 100 g) by 9 months of age, the plasma ferritin level continued to decrease. The level was less than 10 micrograms/L in 54% of the infants at 12 months of age and in 74% at 15 months; this indicated depleted iron stores. Because of delayed development very-low-birth-weight infants eat small amounts of cereal and therefore require iron-fortified formula throughout infancy.

Aging↗
PubMed1990

Metabolic rate and physical development in children at risk of obesity.

Children of obese (group O) and normal-weight (group N) parents who took part in a study of metabolic rates and food intakes when 3-5 years old were restudied 12 years later. There were striking differences between the sexes. Among the 15 adolescent boys, parental obesity predicted more rapid growth (but not adiposity) and an earlier decline in resting metabolic rate (RMR)/kg body weight, and childhood energy intake/kg body weight was not predictive. Among the 10 girls, the opposite pattern was observed; childhood energy intake/kg predicted both body size and adiposity, and parental obesity had less predictive value. The sex differences are consistent with the earlier maturation of girls, and the growth differences with the hypothesis that a low RMR/kg body weight is associated with a precocious pattern of growth and development in children predisposed to obesity.

Adolescent↗
PubMed1990

Drug and solvent misuse and knowledge of HIV infections in 14-16-year-old comprehensive school students.

This study of drug and solvent misuse and knowledge of the HIV link amongst 934 secondary school students, completes a third survey concerned with prevalence of drug misuse. Drug and/or solvent misuse was found in 16% of the sample including 5% who use hard drugs, which since 1985 represents a 3% decline, but a 1% increase in the use of hallucinogens. The misusers were compared with the non-users with regard to their social characteristics, other illegal behaviour and their knowledge of HIV and other public health concerns. There were some surprises concerning the gender results. Misusers were found to be more socially disadvantaged and more involved in other negative behaviour. Despite reasonable knowledge about HIV-related matters, the misuser group were less accurate on all public health issues, appearing to 'deny' the potential risks associated with drug misuse.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Effect of fabric washing on the presumptive identification of bloodstains.

The purpose of this study was to investigate the retention of blood stains on twelve different types of fabrics after washing at various drying times. The findings of this study, supported by chi-square analysis, indicate that the retention of bloodstains on washed fabrics depends upon the particular fiber composition of the fabric, the specific blood screening test used, and whether or not a detergent was used in the wash. The results of this research did not reveal a significant effect of the drying time on the retention of bloodstains, as tested during the 48-h limit of this experiment. The author concludes that the forensic serologist should consider the factors investigated in this study before rendering an opinion on the retention of bloodstains on washed garments.

Blood Stains↗
PubMed1989

Efficacy of intravenous propranolol for suppression of inducibility of ventricular tachyarrhythmias with different electrophysiologic characteristics in coronary artery disease.

The efficacy of intravenous propranolol for suppression of inducibility of sustained ventricular tachyarrhythmias (VT) was studied in 24 patients who had failed greater than or equal to 1 membrane-active antiarrhythmic drug (mean 2.2 +/- 1.2 drugs/patient). The response to propranolol was compared in 13 patients who had only stable monomorphic VTs inducible at baseline and another 11 patients who had greater than or equal to 1 episode of electrically unstable VTs (polymorphic VT, ventricular flutter or ventricular fibrillation) at baseline. Seven patients (29%) became noninducible (responders) and 17 patients (71%) remained inducible to sustained VT (nonresponders) after propranolol. The basal heart rate was faster in responders than in nonresponders (101 +/- 14 vs 86 +/- 11 beats/min, p less than 0.01). The magnitude of heart rate reduction was also greater after propranolol in responders (from 101 +/- 14 to 80 +/- 9 beats/min, p less than 0.001) than in nonresponders (from 86 +/- 11 to 74 +/- 9 beats/min, p less than 0.01) (p less than 0.05 between the groups), despite equal plasma propranolol concentrations (84 +/- 50 vs 88 +/- 43 ng/ml, difference not significant). Seven of 11 patients (64%) who had greater than or equal to 1 episode of unstable VTs inducible at baseline responded to intravenous propranolol, whereas none of the patients with only stable monomorphic VTs became noninducible after beta blockade (p less than 0.001). Responders had shorter cycle length of inducible VTs than nonresponders (225 +/- 38 vs 302 +/- 66 ms, p less than 0.001). Thus, intravenous propranolol appears to be efficacious in suppressing fast, electrically unstable VTs, compared to monomorphic VTs with slower rates.

Aged↗
PubMed1989

Changes in spontaneous sinus node rate as an estimate of cardiac autonomic tone during stable and unstable ventricular tachycardia.

Changes in sinus node rate were measured as an estimate of reflex control of cardiac autonomic tone during 32 episodes of stable ventricular tachycardia (without loss of consciousness) and 21 episodes of unstable ventricular tachycardia (loss of consciousness requiring electrical cardioversion) in 32 patients without retrograde ventriculoatrial conduction. Sinus node rate was measured before induction of ventricular tachycardia (at 5 s intervals during tachycardia) and 5 s after termination of ventricular tachycardia. It increased from 85 +/- 12 beats/min to a maximum of 109 +/- 25 beats/min during stable ventricular tachycardia (p less than 0.001) and from 82 +/- 15 beats/min to a maximum of 105 +/- 34 beats/min during unstable ventricular tachycardia (p less than 0.001). During unstable ventricular tachycardia, the increase in sinus rate was more abrupt and was followed by a sharp decrease beginning before termination of the tachycardia and resulting in a slower rate after termination (56 +/- 15 beats/min) than before tachycardia (p less than 0.001). Stable ventricular tachycardia resulted in a continuous increase of sinus node rate, which remained higher after termination (102 +/- 15 beats/min) than before tachycardia (p less than 0.001). Autonomic mechanisms responsible for changes in sinus rate were evaluated by reinducing the ventricular tachycardia after beta-adrenergic blockade by propranolol in 10 patients. Intravenous propranolol (mean dose 11 +/- 4 mg) had no effect on the magnitude of increase in sinus rate (+18 +/- 6 beats/min before and +17 +/- 7 beats/min after propranolol).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Young adult survivors of sudden cardiac arrest: analysis of invasive evaluation of 22 subjects.

Twenty-two young adult (mean age 27.8 +/- 5.3 years) survivors of sudden cardiac arrest underwent invasive cardiac assessment. Initial evaluation by cardiac catheterization, coronary angiography, and hemodynamic studies identified two groups of young survivors. The first consisted of 13 (60%) subjects who had definable structural cardiac or lung disease accountable for a cardiac arrest event. Dilated cardiomyopathy dominated this group. Mitral valve prolapse, hypertrophic cardiomyopathy, left ventricular hypertrophy, anomalous origin of the right coronary artery, and tetralogy of Fallot were also encountered. The second group included nine subjects (40%) with normal cardiac structure and normal hemodynamic parameters. Electrophysiologic testing demonstrated in three of these patients the presence of Wolff-Parkinson-White syndrome. The electrophysiologic studies had a higher yield in reproduction of life-threatening arrhythmias among the subjects in the second group as opposed to the first group. The observation that 10 subjects (45%) from both groups had preceding symptoms varying from palpitations and chest pain to syncope and recurrent cardiac arrest events, is in contradiction to previous findings in the literature and raises a question of appropriate evaluation of young adults with cardiac symptoms.

Adult↗
PubMed1989

Aldosterone-induced glycoproteins: further characterization.

Aldosterone induces the synthesis of a group of glycoproteins (GP65,70) in toad urinary bladders which are potential effectors of the natriferic action of this hormone. The GP65,70 complex is composed of two molecular weight classes of proteins (Mr 65 and 70 kDa), each class being composed of several discrete proteins of varying isoelectric points (5.8-6.2). These proteins can be partially enriched (approximately 20-fold) using wheat germ agglutinin-sepharose affinity chromatography, are neuraminidase-resistant, and can be N-deglycosylated by endoglycosidase-H and N-glycanase. Treatment with N-glycanase leads to the appearance of a microheterogeneous group of proteins, all having the same Mr (approximately 40 kDa). From these studies it can be concluded that these particular aldosterone-induced proteins: (1) are heavily glycosylated, (2) contain multiple high mannose and hybrid oligosaccharides side chains, and (3) contain similar (if not identical) peptide backbones. Post-translational N-glycosylation accounts, at least in part, for their electrophoretic polymorphism (variation in Mr) but not for their electrophoretic microheterogeneity (variation in pI). The latter may reflect other types of post-translational modification (e.g. O-glycosylation, phosphorylation) or may be due to subtle differences in amino acid composition. The partial purification and biochemical characterization of GP65,70 should ultimately lead to a better understanding of the function of these putative "effectors" of aldosterone-stimulated Na+ transport.

Aldosterone↗
PubMed1989

Time to first shock and clinical outcome in patients receiving an automatic implantable cardioverter-defibrillator.

The relation between time to first shock and clinical outcome was studied in 60 patients who received an automatic implantable cardioverter-defibrillator (AICD) from August 1983 through May 1988. The mean (+/- SD) patient age was 64 +/- 10 years, 82% were men and the mean ejection fraction was 33 +/- 13%. During follow-up, 38 patients (63%) had one or more shocks; there were no differences in age, gender distribution or ejection fraction at entry between the shock and no shock groups. Among 51 patients with coronary artery disease, 31 (61%) had one or more shocks, whereas all seven patients with cardiomyopathy had one or more shocks (p less than 0.05). Neither of the two patients with idiopathic ventricular fibrillation had shocks. Of the 13 deaths, 12 occurred during post-hospital follow-up and 1 during the index hospitalization. Of the four sudden post-hospital deaths, only one was due to tachyarrhythmia in the absence of acute myocardial infarction. All four sudden deaths and five of eight post-hospital nonsudden deaths occurred in patients who had had one or more appropriate shocks during follow-up. Eight of the nine first appropriate shocks among patients who subsequently died occurred within the first 3 months of follow-up, but the actual deaths were delayed to a mean of 14.1 +/- 13.9 months (p less than 0.05). The mean time to all deaths was 14.8 +/- 13.1 months. The ejection fraction was significantly lower among patients who died than among patients who survived (25 +/- 7% versus 35 +/- 14%, p less than 0.02), but it did not distinguish risk of first shocks.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗