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Biomedical subjects

J Mitchell

Publications and source records attributed to J Mitchell.

At least 487 records · Page 27Linked to original sources
PubMedDate not supplied

Passive inhalation of marijuana smoke: urinalysis and room air levels of delta-9-tetrahydrocannabinol.

In two separate studies, 5 drug-free male volunteers with a history of marijuana use were passively exposed to the sidestream smoke of 4 and 16 marijuana cigarettes (2.8% delta-9-tetrahydrocannabinol [THC]) for 1 h each day for 6 consecutive days. A third study was similarly performed with 2 marijuana-naive subjects passively exposed to the smoke of 16 marijuana cigarettes. Passive smoke exposure was conducted in a small, unventilated room. Room air levels of THC and CO were monitored frequently. All urine specimens were collected and analyzed by EMIT d.a.u. assay, Abuscreen radioimmunoassay and GC/MS. The studies show that significant amounts of THC were absorbed by all subjects at the higher level of passive smoke exposure (eg., smoke from 16 marijuana cigarettes), resulting in urinary excretion of significant amounts of cannabinoid metabolites. However, it seems improbable that subjects would unknowingly tolerate the noxious smoke conditions produced by this exposure. At the lower level of passive marijuana-smoke exposure, specimens tested positive only infrequently or were negative. Room air levels of THC during passive smoke exposure appeared to be the most critical factor in determining whether a subject produced cannabinoid-positive urine specimens.

Adult↗
PubMedDate not supplied

Marijuana-laced brownies: behavioral effects, physiologic effects, and urinalysis in humans following ingestion.

Five drug-free male subjects ingested marijuana-laced brownies in a double-blind crossover study designed to test for behavioral effects, physiologic effects, and urinary cannabinoid metabolites produced as a result of consumption of marijuana plant material cooked in foodstuff. On three separate occasions, each subject consumed two brownies which contained 1.6 g of marijuana plant material. Placebo marijuana plant material (0% THC) was mixed with marijuana plant material (2.8% THC) so that each subject ingested equivalent marijuana plant material of 0, 1, and 2 marijuana cigarettes (2.8% THC). Subjects scored significantly higher on behavioral measures after consumption of brownies containing THC than with placebo; however, the effects were slow to appear and variable. Peak effects occurred 2.5 to 3.5 h after dosing. Modest changes in pulse and blood pressure also were noted. Urinalyses by EMIT d.a.u. assay and Abuscreen RIA for cannabinoids and GC/MS assay for THCCOOH indicated that substantial amounts of marijuana-related metabolites were excreted over a period of 3 to 14 days. No positives were produced as a result of ingestion of placebo brownies.

Adult↗
PubMedDate not supplied

Duodenal microflora in infants with acute diarrheal disease.

The duodenal microflora was determined qualitatively and quantitatively in a group of infants early in the course of diarrheal disease. Abnormal bacterial overgrowth in the duodenal aspirate was demonstrated in 70%. Coliforms and bacteroides species were present in significant numbers in 53%. No differences were found in the duodenal microflora distinguishing infants whose diarrhea persisted after 7 days in the hospital from those whose diarrhea resolved earlier.

Acute Disease↗
PubMedDate not supplied

Effects of serotonin antagonists on blood pressure in mineralocorticoid hypertensive sheep.

The serotonin antagonist methysergide has a partial agonistic action on isolated vascular smooth muscle from hypertensive animals, whereas ketanserin, another serotonin antagonist, does not. The goal of this study was to determine the effects of these two agents on blood pressure in the conscious, deoxycorticosterone acetate (DOCA) hypertensive sheep. Adult sheep maintained on a standard laboratory diet and 0.1% NaCl/0.25% KCl drinking water developed hypertension following DOCA implantation (mean arterial pressure: control = 83 mm Hg, DOCA = 108 mm Hg). Methysergide (40 micrograms/kg--i.v. bolus) produced a greater pressor response in hypertensive sheep than in normotensive sheep (control = 8 +/- 1 mm Hg, DOCA = 18 +/- 3 mm Hg). Ketanserin (50 micrograms/kg--i.v. bolus), on the other hand, caused a similar decrease in blood pressure (approximately -16 mm Hg) in both control and DOCA sheep. Pressor responses to infusions of serotonin were greater in DOCA sheep compared with controls. Both methysergide and ketanserin were equally effective antagonists of a serotonin-induced pressor response (75% inhibition) in control and DOCA sheep. Methysergide had no effect on a norepinephrine-induced pressor response, but ketanserin caused a 20% attenuation of this response. These results demonstrate an enhanced responsiveness to serotonin and methysergide in DOCA hypertensive sheep.

Animals↗
PubMedDate not supplied

Buckthorn neuropathy: effects of intraneural injection of Karwinskia humboldtiana toxins.

Ingestion of the endocarp of the coyotillo fruit, Karwinskia humboldtiana, a shrub of the buckthorn family, causes "Buckthorn neuropathy" in man and animals. Two neurotoxic compounds T496 and T544 were isolated from the endocarp and each toxin was dissolved in sesame oil and injected into the sciatic nerve of rats. The nerves were subsequently examined by teasing and as sections by light and electron microscopy. During the first 3--4 days after injection, oil droplets, probably containing toxin, were observed in the cytoplasm of Schwann cells with intact myelin sheaths. Clinical signs of weakness in the limb first appeared at 5--6 days and were accompanied by segmental demyelination mainly of the larger fibres. These observations suggest that the toxins have a primary action on Schwann cell metabolism. The results of local injection of purified toxins are discussed in relation to reports of nerve damage in animals following oral administration of the endocarp where intramyelin vacuole formation and segmental demyelination are prominent features.

Animals↗
PubMedDate not supplied

An ultrastructural study of the early stages of axonal regeneration through rat nerve grafts.

Segments of rat sciatic nerve 5 mm long were removed and either maintained alive in tissue culture medium or killed by freeze-drying. Twenty-four h later the nerve segments were replaced as autografts. Animals were killed 3-14 days after grafting. Grafts of cultured nerves (C-grafts) always contained many living cells. Grafts of freeze-dried nerves (FD-grafts) contained few living cells at 3 days, but were repopulated by 7 days. A few regenerating axons were identified in the most proximal parts of 3 day C-grafts and by 14 days many myelinated axons extended to the distal ends. Axons were absent from 3 and 7 day FD-grafts, but by 14 days some non-myelinated axons extended to the distal end of such grafts. Regenerating axons were always associated with Schwann cells. Small perineurial compartments were formed at the junctional zones of all grafts and throughout the FD-grafts. Revascularization of the FD-grafts was delayed when compared to that in C-grafts. Fenestrated capillaries were observed in both types of graft. These experiments demonstrate that axons regenerate through FD-grafts that have been repopulated by cells and the grafts probably lack the normal perineurial and blood/nerve diffusion barriers. The significance of these results is discussed in relation to the requirements for successful axonal regeneration.

Animals↗
PubMedDate not supplied

The effect of sinus node depression on heart rate variability in humans using zatebradine, a selective bradycardic agent.

Zatebradine is a bradycardic agent with a selective effect on the pacemaker current in the sinus node. The effect of such drugs on heart rate variability is not known. Thirty-six patients without structural heart disease were randomly assigned to receive 10 mg of zatebradine i.v. (n = 24) or isotonic saline (n = 12). Heart rate variability (HRV) was recorded as power in the very low frequency (VLF, 0.003-0.040 Hz), low frequency (LF, 0.040-0.150 Hz), and high frequency (HF, 0.150-0.400 Hz) spectral bands as well as total power (TP, 0.003-0.400 Hz) during 5-min ECG acquisitions at baseline, 30, and 60 min following the start of the infusion. No change in heart rate variability was detected in the control group. Zatebradine significantly reduced heart rate variability at 60 min in all frequency bands: VLF (-12+/-4%, p<0.001), LF (-19+/-4%, p<0.001), and HF (-26+/-5%, p<0.001). The reduction in HRV following zatebradine is due to depression of sinus node response to all external stimuli and underscores the need for documentation of normal sinus node function in HRV research.

Adult↗
PubMedDate not supplied

Jejunostomy tube feedings should not be stopped in the perioperative patient.

BACKGROUND: Anesthetic standard of care is to restrict oral intake for 8 hours before elective surgery. There is no research addressing appropriate preoperative discontinuation of jejunostomy tube (J-tube) feedings. We hypothesized that patients could be fed safely, via a J-tube, until the time of surgery. METHODS: Patients admitted to a Level I Trauma Center, having J-tubes and undergoing a nonabdominal operation, were prospectively evaluated. Group I patients received J-tube feedings until transport to the operating room. Group II patients had tube feedings discontinued for at least 8 hours before surgery. Data were compared using the Student's t test and contingency table analysis. RESULTS: There were 46 patients in group I and 36 in group II. There was no incidence of aspiration. Patient groups did not differ in age, mortality, length of stay, injury severity score, or ventilator days. Group I patients had tube feedings discontinued for fewer hours before and after surgery than group II patients (before surgery: 1.40 +/- 1.20 vs 11.61 +/- 5.01, respectively; p < .001; after surgery: 2.99 +/- 7.49 vs 7.11 +/- 9.03, respectively; p = .043); received more kilocalories/ grams of protein on the day of surgery (group I vs group II, 1676.15/89.57 +/- 1133.21/38.04 vs 791.14/57.58 +/-498.66/79.87, respectively; p = .001/p = .032) and more kilocalories/grams of protein on the first postoperative day (group I vs group II, 1580.74/92.57 +/- 600.53/37.96 vs 1152.47/63.53 +/- 733.96/39.40, respectively; p = .006/p = .001). CONCLUSIONS: Patients receiving J-tubes who are undergoing nonabdominal operations may safely continue enteral nutrition at maximum protein and caloric intake until surgery.

Adult↗
PubMedDate not supplied

Privacy and security: are your health information systems up to standard?

As electronic patient health information systems become more fully developed and widespread, there are persistent concerns about the privacy and confidentiality of the personal health data being stored and disseminated. Standards Australia has released two Standards which provide useful guidelines for the organisational, technological and human behavior solutions required to protect privacy and confidentiality in health care organisations. The major requirements of these Standards are outlined and the implications of the Standards for health information managers are discussed.

Australia↗
PubMedDate not supplied

Accredited clinical coder examination 1996 results.

In September 1996, 148 candidates sat for the first Australian Clinical Coder (ACC) accreditation examination at 19 sites across Australia and New Zealand. This event was an important milestone for clinical coders in Australia. Around one third of the candidates who sat for the exam gained accreditation. The results show that the candidates who were most likely to be successful in gaining accreditation: worked in public hospitals (of any size) or private hospitals with more than 150 beds spent 25 hours or more each week on coding or coding-related activities had been coding for three or more years. The greatest percentage of successful candidates had been coding for 10 or more years.

Accreditation↗
PubMedDate not supplied

University entry scores as a predictor of academic performance in a health information management program.

The university entry scores for school leavers admitted to the first year of the Bachelor of Applied Science (Health Information Management) degree at the University of Sydney in 1996 were examined to determine whether the Tertiary Entrance Rank (TER) was a good predictor of academic performance, as measured by grade point average (GPA). The study also examined Higher School Certificate (HSC) results in English and mathematics, and preference selection for the health information management (HIM) course to determine whether any of these had predictive validity. The results showed that TER, HSC English and mathematics scores and preference for the course were all poor predictors of academic performance in the student's first year. Low TER was not associated with low GPA and low scores in English and mathematics were not associated with low GPA. There was no significant difference between the performance of those students who listed the HIM course as their first preference and those who did not. These results suggest that there may be no need to establish a minimum entry level for admission to the HIM course, or for prerequisites in English and mathematics. It may be that multiple criteria are required to predict academic success in this course.

Achievement↗
PubMedDate not supplied

A randomized trial of nelfinavir, ritonavir, or delavirdine in combination with saquinavir-SGC and stavudine in treatment-experienced HIV-1-infected patients.

PURPOSE: To evaluate the 24-week impact of saquinavir-enhancing antiretroviral therapy on viral replication in patients previously treated with nucleoside analogues with or without prior saquinavir hard-gel capsules (HGC). METHOD: Patients were randomized in three groups to receive the following: Group 1-nelfinavir (750 mg tid), saquinavir soft-gel capsule (SGC) (800 mg tid), and stavudine (40 mg bid); Group II-ritonavir (400 mg bid), saquinavir-SGC (400 mg bid), and stavudine (40 mg bid); or Group III-delavirdine (400 mg tid), saquinavir-SGC (800 mg tid), and stavudine (40 mg bid). Viral loads, CD4 count, and safety were assessed over a 24-week period with an additional 6-month follow-up. RESULTS: 73 patients received randomized therapy; 14 of whom were SQV naïve, with a median baseline viral load of 3.6 log(10) and a CD4 count of 370 cells/mm(3). By 6 months, the median decreases in plasma viral loads were 0.26, 0.71, and 0.29 log(10) copies/mL for groups I, II, and III, respectively. The median increases in CD4 counts, for groups I, II, and III, were 52, 40, and 69 cells/mm(3) at 6 months, respectively. Changes in viral load and CD4 counts at 6 months and 1 year were not significantly different between the treatment groups. More patients discontinued therapy in the ritonavir arm (35%) for drug intolerance or toxicity compared to either the nelfinavir or delavirdine arms (15% and 5%, respectively). In a multivariate analysis, baseline viral load, younger age, and baseline saquinavir resistance were significantly associated with detectable viral load at 24 weeks. CONCLUSION: The use of antiretroviral agents that pharmacokinetically boost saquinavir levels has a modest benefit in saquinavir-experienced patients.

Adult↗