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Biomedical subjects

D Wilkins

Publications and source records attributed to D Wilkins.

At least 37 records · Page 2Linked to original sources
PubMed1995

Quantitative analysis of THC, 11-OH-THC, and THCCOOH in human hair by negative ion chemical ionization mass spectrometry.

A sensitive and specific method was developed for the quantitative analysis of delta9-tetrahydrocannabinol (THC), 11 -hydroxy-THC (11-OH-THC), and 11-nor-9-carboxy-THC (THCCOOH) in human hair. Deuterated internal standards were added to hair samples, and samples were digested overnight in 1 N NaOH at 37 degrees C. Digest solutions were extracted with a liquid-liquid extraction procedure, which was previously developed in our laboratory for the analysis of plasma and whole blood. Derivatized extracts were analyzed on a Finnigan 4500" mass spectrometer in negative ion chemical ionization mode using methane as the reagent gas, hydrogen as the carrier gas, and a Restek Rtx 200-15M-0.25-microm capillary column. The assay was linear up to 50 ng/mg hair (r, 0.99) for all three compounds and was capable of detecting 10 pg THC and THCCOOH and 100 pg 11-OH-THC on column. The intra-assay precision ranged from 2.1 to 11.2% for the three analytes; the interassay precision ranged from 4.4 to 13.0%. The method was used to detect and quantitate the presence of THC, 11-OH-THC, and THCCOOH in human hair obtained from eight regular users of cannabis. THC, but not 11-OH-THC or THCCOOH, was detectable in the hair shaft above the assay limit of quantitation. Four laboratory wash procedures were also evaluated for their effect on the measured concentration of THC in hair. in seven of eight subjects, a methylene chloride wash procedure substantially reduced the measured THC concentration by up to 50%. The gas chromatographic-mass spectrometric assay is currently being used to support pharmacokinetic studies of drug disposition into the hair of humans and animals.

Boranes↗
PubMed1994

Tuberculosis: medical students at risk.

In 1979 an outbreak of tuberculosis occurred in medical students at the University of Sydney. Eight of 35 Mantoux-negative students who attended the autopsy of an immunosuppressed patient with unsuspected active tuberculosis became infected and one developed clinical disease. A report of the incident was prepared for publication because it supported the then controversial University policy of recommending BCG vaccination to medical and dental students in a country where the reported prevalence of tuberculosis is very low. The report was never published, mainly in order to protect the privacy of the individual students involved, but also because it was felt by the administration of the time that it might undermine confidence in infection control procedures in the autopsy room. The original report, updated and reproduced here, suggested that tuberculosis might be an emerging nosocomial problem. This has been all too clearly realised since its re-emergence as an opportunistic infection in AIDS patients. Worldwide, the problem of antibiotic resistance in Mycobacterium tuberculosis provides an added risk of a return to the situation which prevailed early this century when tuberculosis was a major occupational risk for young health care workers. Infection often restricted career choices, even in those whose disease was relatively benign. Our purpose in bringing this incident to light after so many years is to point out the relevance of the extensive studies of the problem which were conducted in the 1930s and 1940s to the current situation and to suggest that health care students are vulnerable to airborne infections as well as those spread by inoculation injuries. In retrospect, our 1979 conclusions about prospects for preventing nosocomial tuberculosis appear optimistic.

Autopsy↗
PubMed1994

Rubisco and PEP carboxylase responses to changing irradiance in a Brazilian Cerrado tree species, Qualea grandiflora Mart. (Vochysiaceae).

The activities of ribulose-1,5-bisphosphate carboxylase-oxygenase, Rubisco (E.C. 4.1.1.39) and phosphoenolpyruvate carboxylase, PEPc (E.C. 4.1.1.31), and concentrations of protein and chlorophyll were measured in extracts from cotyledons and first leaves of Qualea grandiflora Mart. (Vochysiaceae) seedlings after transfer from high-light (20 days at 320 micro mol m(-2) s(-1), PAR) to low-light (35 days at 120 micro mol m(-2) s(-1), PAR) conditions. When Tween 20 and glycerol were added to the extraction medium, Rubisco activities obtained for Qualea grandiflora were comparable to published values for several coniferous species and the broad-leaved species, Prunus avium L. Stella, grown in a similar light environment. Rubisco activity in cotyledons of Q. grandiflora grown in high light for 20 days and then transferred to low light for a further 35 days was similar to the activity in cotyledons of plants grown continuously in high light. However, the first leaf above the cotyledons showed a greater response to the change in irradiance; in high light, Rubisco activity of the first leaf was 1.8 times higher on a fresh weight basis and 2.7 times higher on an area basis than that of leaves transferred from high to low light. Fresh weight and chlorophyll concentration expressed on a unit leaf area basis were also higher in the high-light treatment. These responses to irradiance are indicative of a species adapted to growth in an unshaded habitat. The PEPc activity in leaves was 15% of Rubisco activity, which is typical of species with a C(3) photosynthetic pathway. The relatively slow growth rate of Q. grandiflora observed in these experiments could not be attributed to a low carboxylation capacity per unit leaf area.

Journal Article↗
PubMed1993

A comparison of laparoscopically assisted vaginal hysterectomy vs traditional total abdominal and vaginal hysterectomies.

The objective of this work was to compare laparoscopically assisted vaginal hysterectomy to traditional total abdominal and vaginal hysterectomies in seven critical areas: anesthesia time, surgery time, hospital stay, operative blood loss, total analgesic use, time required to return to work, and total cost of each of these procedures. The first 25 unscreened, consecutive laparoscopically assisted vaginal hysterectomies performed by the senior author were compared with 25 randomly selected traditional total abdominal and 25 randomly selected vaginal hysterectomies performed by the senior author's professional corporation. Laparoscopically assisted vaginal hysterectomy compared favorably to abdominal and vaginal hysterectomy in three areas and was superior to both total abdominal hysterectomy and vaginal hysterectomy in the remaining four areas. Although the use of the endoscopic stapling device and laser made the laparoscopically assisted vaginal hysterectomy a more expensive procedure than traditional vaginal hysterectomy, the expense was not significant and was justified by the decreased surgery time. The results of this comparative study suggest that laparoscopically assisted vaginal hysterectomy is superior or comparable to total abdominal hysterectomy and vaginal hysterectomy, especially for patients who may not have been candidates for vaginal hysterectomy. This procedure has allowed the gynecologic endoscopic surgeon to convert abdominal to vaginal procedures. Laparoscopically assisted vaginal hysterectomy provides an overall cost savings to the patient, has a low complication rate, adapts well to the outpatient setting, causes less patient discomfort, and allows the patient to return rapidly to home and workplace.

Adult↗
PubMed1985

Primary writing tremor and myoclonic writer's cramp.

Four patients with primary writing tremor had a focal, task-specific tremor that responded to anticholinergic drugs. Physiologic features included EMG activity alternating in antagonist muscles, 5- to 20-microV cerebral potentials evoked by stretch of pronator teres, and no C-reflexes. Another patient had myoclonic jerks of the forearm on attempts to write ("myoclonic writer's cramp") that also responded to anticholinergic drugs; EMG activity appeared synchronously or alternating in antagonist muscles. These disorders have features of dystonia and enlarge the spectrum of writer's cramp.

Adult↗
PubMed1982

Prediction of energy requirements of obese patients after massive weight loss.

A regression analysis was made of resting metabolic rate on weight and body composition in 140 women with varying degrees of obesity. In 19 severely obese women before weight loss, average resting metabolic rate was 290 ml O2/min, or 4 per cent higher than predicted from the regression equation. After losing 30 kg in one year the average metabolic rate of this group was 234 ml O2/min, 1 per cent higher than that predicted for their reduced weight. Women whose metabolic rate was high or low relative to prediction before weight loss tended to maintain this status after weight loss (P less than 0.05). There is a close relation between resting metabolic rate and total energy expenditure. We conclude that there is a reduction in energy requirements for weight maintenance after massive weight loss, but the requirements of obese patients after weight loss are similar to those of people of comparable weight who have not reduced.

Adolescent↗
PubMed1981

The effect of meal frequency and protein concentration on the composition of the weight lost by obese subjects.

1. Nitrogen balance, weight loss and resting metabolic rate were measured in thirty-eight obese inpatients on 3.4 MJ (800 kcal)/d diets over 3 weeks. 2. All subjects were fed on 13% protein-energy in three meals/d for the first week. 3. In weeks 2 or 3, using a cross-over design, ten subjects were fed on 15 or 10% protein-energy as three meals/d; fourteen subjects were fed on five or one meal/d with 13% protein-energy; and fourteen subjects were fed on 15% protein-energy as five meals/d or 10% protein-energy as one meal/d. 4. N loss was least on the high-protein week and frequent-meal week: the largest difference was found when these effects were combined (P less than 0.001). 5. When protein-energy was held constant at 13% N loss decreased significantly (P less than 0.01) between week 2 and 3, but when the protein-energy was manipulated there was no significant N conservation in the third week. This suggests that the protein:energy value is more important than meal frequency in the preservation of lean tissue. 6. Weight loss was also least on the 'high-protein' week and 'frequent-meal' week, but this result reached significance only when the effects were combined (P less than 0.05). 7. Resting metabolic rate decreased with time but was not significantly altered by the dietary regimens. 8. Therefore, during the first 3 weeks at an intake of 3.4 MJ/d, a diet with a high-protein concentration, fed as frequent small meals, is associated with better preservation of lean tissue than an isoenergetic diet with lower-protein concentration fed as fewer meals. There was no evidence that meal frequency or protein concentration affect the rate of fat loss.

Adolescent↗
PubMed1977

Breakdown of mucin and plant polysaccharides in the human colon.

To obtain an estimate of the extent to which complex carbohydrates are degraded by bacteria in the human colon, aqueous extracts of colon contents from four human subjects were separated into high and low molecular weight fractions by chromatography on a Sephadex G-100 column. The composition of these fractions was compared with the composition of similar fractions from ileal contents, i.e., from material entering the colon. In all four subjects, high molecular weight carbohydrate concentrations were lower in the colon than in the ileum, indicating that breakdown of complex carbohydrate occurs in the colon. The high molecular weight carbohydrate fraction contained sugars characteristic of plant polysaccharides (arabinose, xylose, mannose, rhamnose) as well as sugars characteristic of mucin (fucose, hexosamines, sialic acids). Concentrations of most of these sugars were uniformly lower in the colon than in the ileum. Since high molecular weight protein concentrations were lower in the colon than in the ileum of two of the four subjects tested, some degradation of protein may also occur in the colon.

Amino Acids↗
PubMed1976

Qualitative and quantitative histochemical changes in the caecum and liver of turkeys infected with Histomonas meleagridis.

Changes in the amount and distribution of acid and alkaline phosphatase, non-specific esterase, glycogen, lipid and acid mucopolysaccharide in the caecal wall and liver of turkey poults infected with Histomonas meleagridis have been studied histochemically. A microdensitometer was used to measure changes in activity and distribution of acid phosphatase and non-specific esterase in the caecal mucosa. During the course of the infection there is a marked reduction in activity and distribution of acid phosphatase and non-specific esterase but little change in the amounts and distribution of alkaline phosphatase, glycogen, lipid and acid mucopolysaccharide in the wall of the main part of the caecum. Similar, but smaller, changes occurred in the wall of the neck region of the caecum. In the liver most changes occurred in the immediate vicinity of the parasites. Initially, there was a reduction in the amount of glycogen in the parasitic lesions but later in the infection there was a marked loss of glycogen in all regions of the liver. Changes in the caecum are apparently brought about by the parasite prior to and after invasion of the caecal tissues; changes in the liver occur after it has been invaded.

Acid Phosphatase↗
PubMedDate not supplied

Consultation/liaison psychiatry utilization patterns in different cultural groups.

This study examined the effect of cross-cultural factors on psychiatric consultations in a general hospital. Using a retrospective case review, 476 patients receiving a psychiatric consultation were contrasted with 14,620 who did not receive a psychiatric consultation. The rate of psychiatric referral was lower for Hispanics compared with Anglos, blacks, and Asians (p less than 0.001). The reason for requesting psychiatric consultation was also different across the ethnic groups. There were more requests for evaluation of depression and suicide in Hispanics and fewer such requests in blacks. More requests for evaluation of grossly abnormal mental status were found in blacks. The different cultural groups also had differences in psychiatric diagnosis. Hispanics were more frequently diagnosed with an adjustment disorder; blacks were more frequently diagnosed with a primary thought disorder and delirium; and Anglos were more frequently diagnosed with dementia.

Cross-Cultural Comparison↗