Biomedical subjects

L I Stowell

Publications and source records attributed to L I Stowell.

10 recordsLinked to original sources

PubMed1998

Estimation of blood alcohol concentrations after social drinking.

Requests for estimates of blood alcohol concentrations (BACs) are often made when blood samples are taken some hours after the time of interest. Many believe that such estimates are not reliable because the subject's alcohol clearance rate is never known and often there is uncertainty as to whether the subject was postabsorptive at the time in question. In order to evaluate the potential errors associated with BAC estimates under these non-ideal conditions, BAC estimates were compared with empirical data obtained from 24 healthy males, ranging in age from 22 to 56 years, who took part in a three hour social drinking session. One blood sample for alcohol analysis was taken from each subject approximately 1 hour after drinking stopped and another was taken approximately 3.5 hours after drinking stopped. Estimations of BACs at the blood sampling time points were made assuming each person had a constant blood alcohol clearance rate in the range of 10 to 20 mg/dL/h (0.01 to 0.02 g/dL/h) over the whole of the experimental period. A variety of methods were used to estimate the volume of distribution for alcohol. All BAC estimations were made assuming complete absorption and full equilibration of the total alcohol dose. The results showed that actual BACs were usually within or very close to the range of "forward" estimates based on the known alcohol doses. Furthermore, most BACs measured about an hour after cessation of drinking were within or very close to the predicted range based on back extrapolation from the actual 3.5 hour BAC result.

Adult↗

PubMed1997

Interpreting DNA mixtures.

The interpretation of mixed DNA stains is explained in the context of likelihood ratios. The probabilities for the mixed-stain profile are evaluated under alternative explanations that specify the numbers of contributors and the profiles of any known contributors. Interpretations based simply on the frequencies with which random members of a population would not be excluded from a mixed-stain profile do not make use of all the information, and may overstate the strength of the evidence against included people. The effects of the numbers of contributors depends on whether all the alleles at a locus are present in the mixed stain. A general equation is given to allow likelihood ratios to be calculated, and includes the "2p" modification suggested by the 1996 NRC report. This modification is not always conservative. A computer program to perform calculations is available.

Alleles↗

PubMed1992

Autonomic responses to carbohydrate ingestion and head-up tilt in elderly subjects with orthostatic hypotension.

To investigate the role of glucose and insulin in the development of hypotension following glucose ingestion in elderly subjects with orthostatic hypotension, the autonomic responses to glucose and xylose ingestion were studied in five elderly subjects with age related orthostatic hypotension (without autonomic failure), five elderly control subjects and three elderly subjects with evidence of autonomic failure. Heart rate, blood pressure, plasma noradrenaline and plasma arginine vasopressin responses to glucose ingestion and to xylose ingestion were investigated. All subjects were supine for 90 min following ingestion of each carbohydrate and were then tilted 45 degrees head-up for 10 min. Blood pressure was maintained in elderly control subjects following ingestion of both carbohydrates and during tilting. The elderly group with orthostatic hypotension, while supine had a fall in systolic blood pressure 60-90 min following both glucose and xylose ingestion. Diastolic blood pressure was lowered 60-90 min after glucose but not xylose. During tilting, blood pressure fell by similar levels following both carbohydrate ingestions; plasma noradrenaline levels after 2 min and plasma arginine vasopressin levels after 10 min tilting were significantly less following glucose ingestion compared to xylose ingestion. The autonomic failure group while supine had a fall in systolic blood pressure 60-90 min following both glucose and xylose ingestion. Diastolic blood pressure was lowered 60-90 min after glucose but not xylose. During tilting, blood pressure fell by similar levels following both carbohydrate ingestion. Plasma noradrenaline and arginine vasopressin levels were unchanged after ingestion of either carbohydrate, and during tilting.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1990

Is orthostatic hypotension in the elderly due to autonomic failure?

In order to investigate whether orthostatic hypotension in elderly people is due to autonomic nervous system dysfunction or blood vessel abnormalities, we have measured platelet and lymphocyte adrenoceptor numbers and agonist binding in addition to venous plasma catecholamine concentrations. Eight elderly subjects with orthostatic hypotension and six control elderly subjects were studied. None of the subjects had other symptoms of autonomic failure. There was no significant difference between the heart rate or plasma catecholamine responses to standing of the two groups. The orthostatic hypotension subjects had a significant rise of their plasma vasopressin levels whereas the control group had no significant change. The number of alpha 2-adrenoceptor sites in platelets was lower in the orthostatic hypotensive group compared to the controls and the binding affinity was greater than in the controls. There were no significant differences in beta-adrenoceptor binding sites or affinities in isolated lymphocytes between the two groups. The similar changes in heart rate and catecholamines together with the vasopressin changes suggest that, in these elderly patients with an abnormal drop of blood pressure on standing, there is no dysfunction of autonomic pathways concerned with cardiovascular function. The lower numbers of alpha 2-adrenoceptor sites on isolated platelets in subjects with orthostatic hypotension could indicate reduced alpha 2-adrenoceptor numbers on their blood vessels which could contribute to their inability to maintain blood pressure while standing.

Aged↗

PubMed1989

Behavior of animal blood in blood typing systems. Isoelectric focusing of erythrocyte acid phosphatase and phosphoglucomutase.

Isoenzyme band patterns of animal blood erythrocyte acid phosphatase (EAP) and phosphoglucomutase-1 (PGM) were studied by isoelectric focusing on ultrathin polyacrylamide gels. For blood from all animals tested (dog, cat, cow, sheep, and goat), the overall band patterns for both isoenzymes were different from those of the most common human types of these enzymes, although some animal EAP and PGM bands appeared in the human band areas. When mixtures of human and animal red blood cells were studied, it was found that misinterpretation of human types was possible only if the overall band pattern of the mixtures was ignored. For the animal blood tested, the strong PGM bands appearing outside the human band areas could be used as "markers" for the possible presence of animal blood in the samples tested.

Acid Phosphatase↗

PubMed1988

Adrenoceptor and imipramine receptor binding during the menstrual cycle.

The binding characteristics of platelet alpha 2-adrenoceptors, lymphocyte beta 2-adrenoceptors and platelet imipramine receptors were studied in five women during their menstrual cycle. A significant cyclic variation in the number of beta 2-adrenoceptor sites on intact lymphocytes was found during the menstrual cycle, while binding to alpha 2-adrenoceptors and imipramine receptors remained unchanged.

Adult↗

PubMedDate not supplied

An enzyme-linked immunosorbent assay (ELISA) for prostate-specific antigen.

A sandwich ELISA for human prostate-specific antigen (PSA) is described. Optimal assay conditions, resulting in a sensitive assay with a low background, are presented. The method uses a hyperimmune antiserum produced in the New Zealand white rabbit, against human semen PSA. The IgG fraction of the antiserum was conjugated with horseradish peroxidase and used in the sandwich ELISA method. The anti-PSA IgG showed no cross reactions with saliva, normal blood, female urine, vaginal fluid, or menstrual blood. On occasions, a blood sample showed a non-specific cross-reaction, which was detected by non-immune rabbit IgG. This reaction could be caused by rheumatoid factors, as indicated by experiments with a series of known IgG and IgM rheumatoid antibodies, although other heterophilic antibodies could not be eliminated. The recovery of PSA added to blood plasma, saliva and vaginal fluid was affected by three factors; (a) protein concentration (dilution) of body fluid; (b) nature of the protein; and (c) amount of PSA added.

Antigens, Neoplasm↗

PubMedDate not supplied

Typing of human red cell and serum mixtures in three electrophoretic systems.

The isoenzymes erythrocyte acid phosphatase and phosphoglucomutase were typed in mixed red cell samples which had been derived from two individuals; the protein group specific component was typed in mixed serum samples. Typing was performed by isoelectric focusing on ultrathin polyacrylamide gels. Depending upon the mixture, from 2 to 20% (but typically 5-10%) by volume of a second blood or serum needed to be present in a mixture before it could be detected. In the majority of cases when there was significant mixing, samples were readily identified as a mixture when the results consisted of unusual band patterns or unusual band intensities. There would be a few instances when blood or serum could not be identified as a mixture when masking effects occurred or when the mixture produced a combined, apparently normal, pattern.

Acid Phosphatase↗

PubMedDate not supplied

Suicide with the veterinary drug acepromazine.

A suicide case involving the veterinary drug acepromazine is described. After a single-step liquid alkaline extraction, acepromazine was identified in a chest-cavity blood sample using gas chromatography (GC) with nitrogen-phosphorus (NPD) and mass selective detectors. Acepromazine was then quantitated in the blood and other postmortem tissues by GC with NPD using chlorpromazine as the internal standard. Acepromazine concentrations in the chest-cavity blood, liver, brain, and bile were 0.6, 3.0, 0.4, and 6.5 micrograms/mL, respectively. The stomach contents contained a total of 2.5 mg acepromazine.

Acepromazine↗

PubMedDate not supplied

Comparison of two commercial test kits for quantification of serum carbohydrate-deficient transferrin.

Serum levels of carbohydrate-deficient transferrin (CDT) were measured in subjects of two independent studies using two different commercial kits. The kits measure CDT either as a percentage of total transferrin (AXIS %CDT, AXIS Biochemicals AS, Norway), or as the absolute amount (CDTect, Pharmacia, Sweden). In a population of males (mean age 41 years) consisting of alcoholics, heavy, moderate and non-drinkers, a strong correlation was found between AXIS %CDT and CDTect results (r = 0.92, n = 58, P < 0.001). Sensitivity and specificity in detecting chronic alcoholic drinking of over 60 g/day were 78 and 94% for the AXIS assay, and 83 and 88% for the CDTect assay, respectively. In a population from a birth cohort study, consisting of 21-year-old males and females with less excessive alcohol consumption, the correlation between AXIS %CDT and CDTect CDT was weaker but still statistically significant (r = 0.46, n = 212, P < 0.001). In this population, with specificities > 83% in detecting alcohol consumption levels of > or = 6 drinks per week, the sensitivities were low with both CDT assays (< 43% for > or = 6 drinks per week, and < 44% for > or = 16 drinks per week). These results suggest that (a) both assays are equally effective in detecting chronic drinking over 60 g/day in older alcoholic males, and (b) both assays are similarly ineffective in detecting less excessive regular drinking in young males and females.

Adult↗