Search PubMed⌕ Search

Biomedical subjects

R R Reeves

Publications and source records attributed to R R Reeves.

At least 55 records · Page 3Linked to original sources
PubMed1995

Cannabinoids in humans. II. The influence of three methods of hydrolysis on the concentration of THC and two metabolites in urine.

Glucuronide conjugates of cannabinoids were previously identified in humans. For gas chromatographic-mass spectrometric (GC-MS) analysis of the unconjugated compounds in human urine, it is necessary to cleave the glucuronide moiety. Base hydrolysis and two forms of enzymatic hydrolysis were compared in this study to examine any quantitative differences between the hydrolysis methods. Human volunteers (n = 8) each smoked one marijuana cigarette containing 3.58% delta 9-tetrahydrocannabinol (THC) and submitted urine samples prior to smoking, 5 min after smoking, and hourly for 8 h thereafter. Urine (1 mL) was buffered to the optimum pH for each form of enzyme tested. beta-Glucuronidase from Escherichia coli (bacteria) or Helix pomatia (mollusk) was added to the specimens, followed by overnight incubation at 37 degrees C. Following hydrolysis, the samples were extracted using hexane-ethyl acetate (7:1) and derivatized with N,O-bis(trimethylsilyl)-trifluoroacetamide plus 1% trimethylchlorosilane, which converted the cannabinoids to their trimethylsilyl derivatives. GC-MS analysis revealed striking differences between the hydrolysis methods. Concentrations of unconjugated THC and 11-hydroxy-THC (11-OH-THC) using E. coli were significantly increased over all other methods tested (p < .05). These results demonstrate the species-dependent nature of glucuronidase activity in hydrolyzing THC and 11-OH-THC glucuronides and the ineffectiveness of base hydrolysis on these hydroxylated compounds. The need for further study to find the optimum conditions necessary for the complete hydrolysis of cannabinoid conjugates is suggested.

Dronabinol↗
PubMed1995

Cocaine-induced ischemic cerebral infarction mistaken for a psychiatric syndrome.

We present the case of a 39-year-old woman who developed an ischemic cerebral infarction after using cocaine. Initially the patient was thought to suffer from a psychiatric disorder, and a computed tomography (CT) scan at the time of admission was entirely normal. Further evaluation of the patient by staff on the Psychiatric Unit led to the suspicion that she had suffered a stroke. A repeat CT scan on the third hospital day showed a large infarction in the left middle cerebral artery territory. We discuss the diagnosis of cerebral infarction with subtle presentations due to cocaine use.

Adult↗
PubMed1995

Topographic quantitative EEG measures of alpha and theta power changes during caffeine withdrawal: preliminary findings from normal subjects.

Neurophysiological consequences of withdrawal from caffeine are poorly understood. In particular, quantitative studies of EEG changes that may occur during the period of caffeine abstinence in caffeine dependent individuals have not been reported. In this pilot study, 13 physically- and psychiatrically-normal caffeine users were asked to abstain from caffeine for a period of 4 days. Quantitative EEGs were obtained prior to stopping caffeine and on Days 1, 2, and 4 of the caffeine abstinence period. Results indicated that significant increases in alpha and theta absolute power accompany the caffeine withdrawal process with return to the pre-abstinent EEG levels when caffeine usage is resumed. The implications of these findings are discussed with special reference to the possible need to control for the variable of caffeine usage in quantitative EEG studies of other phenomena.

Adolescent↗
PubMed1995

A standardized form for DSM-IV review of symptoms and mental status examination for students and residents.

A common error by medical students and residents is the inadvertent omission of some part of the mental status examination or failure to screen for a psychiatric diagnosis that is not evident on the patient's presentation. The authors introduce a structured questionnaire and standardized form to guide psychiatric and generalist medical trainees through the mental status examination. Based on criteria from the Diagnostic and Statistical Manual of Mental Disorders--Fourth Edition (DSM-IV), the questionnaire and form are intended to facilitate a psychiatric review of patients without missing key points.

Humans↗
PubMed1993

Trifocal independent periodic lateralized epileptiform discharges.

The EEG of a 2 1/2-year-old female with a severe cerebral insult showed trifocal periodic lateralized epileptiform discharges (TRIPLEDs). We believe this is the first such record reported. As with BIPLEDs, the physical findings associated with this EEG appear to represent a diffuse cerebral insult. The most frequent causes of BIPLEDs are diffuse anoxic encephalopathy and CNS infection. In this patient, the TRIPLEDs are apparently due to a severe anoxic insult suffered in utero. As is true with BIPLEDs, the presence of TRIPLEDs represents a poor prognosis.

Asphyxia Neonatorum↗
PubMed1977

Perfusion of intact skin by a saline solution of bis(glycinato) copper(II).

The perfusion of intact cat skin by a saline solution of bis(glycinato) copper(II), labelled with Cu64, has been studied in a diffusion cell. It has been shown by counting the activity that the copper(II) complex perfuses the skin and over a period of 6-7 hr reaches the isotonic saline solution underneath. After this inaugural delay period a steady rate of penetration was maintained and after 24 hr about 1 mg of the complex perfused the skin. Skin samples, taken before and after, were fixed in buffered formalin and embedded in paraffin. Five micron sections were taken, stained with rubeanic acid and counterstained with 1% Eosin Y solution. Histological examination showed that copper was present in all layers of the perfused skin. This work is relevant to the solubility of metallic copper in human sweat and to the possible therapeutic value of the "copper bracelet".

Animals↗