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Biomedical subjects

R A Moore

Publications and source records attributed to R A Moore.

At least 217 records · Page 12Linked to original sources

Hemodynamic effects of calcium chloride in adults with regurgitant valve lesions.

We evaluated the hemodynamic effects of 7 mg/kg intravenous calcium chloride (CaCl2) or placebo in 20 adults with regurgitant aortic and/or mitral valves before and after induction of anesthesia with fentanyl (50 micrograms/kg), followed by pancuronium (0.1 mg/kg) and 100% oxygen. CaCl2 produced no changes in mean systemic, pulmonary arterial, central venous, or pulmonary capillary wedge pressures or vascular resistances before or after induction of anesthesia. A significant increase in left ventricular stroke work index was seen 1 min after CaCl2 was administered after induction of anesthesia (from 31.29 +/- 3.00 to 37.44 +/- 3.81 g X m X M-2). Before induction, CaCl2 decreased heart rate from 93.9 +/- 9.6 to 85.2 +/- 8.7 beats/min (statistically significant 2.5 and 10 min after CaCl2) and after induction from 104.6 +/- 8.4 to 89.3 +/- 7.5 (significant at 1, 2.5, 5, and 10 min). These results suggest that CaCl2 is associated with an immediate increase in ventricular performance and that the subsequent decrease in heart rate is not sufficient to contraindicate use of CaCl2 as an inotrope in patients with chronic valvular regurgitation. The effects of CaCl2 injection in man on pulmonary shunt fraction (Qs/Qt) have not been described previously. We found no change in Qs/Qt, suggesting that CaCl2 has no direct effect on distribution of pulmonary blood flow.

Aortic Valve Insufficiency↗

Aminoglycoside dosing service provided by baccalaureate-level pharmacists.

An aminoglycoside pharmacokinetic dosing service operated primarily by baccalaureate-level pharmacists is described. The service was initiated gradually by the clinical pharmacy coordinator. After detailed policies and procedures were developed, staff pharmacists received 14 hours of training in pharmacokinetics. The training program consisted of written study material and application to actual patient cases. The pharmacokinetic dosing service is initiated upon the written request of a physician. Nurses on the pharmacy i.v. team administer aminoglycoside doses, collect blood samples, and record sample collection and drug infusion times whenever possible; when workload is heavy, floor nurses and laboratory personnel assist in these functions. The entire dosing consult requires approximately one hour of pharmacist time per patient. A $20 fee is assessed for completed dosing consults. Approximately 50 consults are provided per months, and a survey showed that 50-70% of all hospital patients (except newborns in intensive care) receiving aminoglycosides had their dosages calculated by the service. A carefully developed limited aminoglycoside dosing service provided primarily by baccalaureate-level pharmacists has given the pharmacy department at this hospital an opportunity to further expand its involvement in clinical pharmacokinetics.

Aminoglycosides↗

Current status of the field: contrasting perspectives. A medical clinician's perspective.

Because alcoholism is viewed and treated as a bad habit, almost all treatment approaches are covertly behavioral. Behavior therapy as a specific and overt approach to alcoholism is widely written and talked about. Nevertheless, it is not the major approach utilized in the majority of treatment programs. This is a result of a trend toward deprofessionalization in the field manifested by a reluctance to accept ideas not compatible with accepted with accepted dogma, a reluctance of professionals dynamically oriented to accept behavioral approaches, and a lack of belief in the efficacy of behavior therapy. It is vital to keep the field open to new ideas and facts; if we do, behavior therapy has a bright future in the treatment of alcoholism.

Alcoholism↗

Chlorpropamide-alcohol flushing and plasma chlorpropamide concentrations in diabetic patients on maintenance chlorpropamide therapy.

Forty-three diabetic patients on maintenance chlorpropamide (100-750 mg daily) drank 0.2 ml/kg 90% ethanol after equilibration in a room controlled at 20 degrees C. Twenty-five patients had already noted marked alcohol flushing since starting chlorpropamide therapy (group A), while 13 had not observed this (group B). The remainder were teetotal or unsure of their reaction. Cheek temperature rise correlated with plasma chlorpropamide concentration (r = 0.6, p less than 0.001) in all patients and was inversely related to basal cheek temperature (r = -0.35, p less than 0.02). Plasma chlorpropamide correlated with daily chlorpropamide dose (r = 0.8, p less than 0.001) but not with basal cheek temperature. The correlation between chlorpropamide level and cheek temperature rise was strengthened on analysis of group A alone (r = 0.7, p less than 0.001) and absent in group B (r = 0.2, p greater than 0.3) who tended to have lower chlorpropamide levels and cheek temperature rise than group A.

Body Temperature↗

Brain neuronal RNA metabolism during acute soman toxication: effects of antidotal pretreatments.

Effects of various antidotal treatments on neuronal RNA contents and on soman induced RNA and acetylcholinesterase (AChE) depletion were monitored using quantitative cytochemical techniques. In rats only with antidotes, atropine depressed whereas pralidoxime (2-PAM) elevated RNA contents of both caudate and cerebrocortical (Layer V) neurons. Soman produced a virtually complete inhibition of AChE activity and a moderate decline in neuronal RNA contents. Atropine pretreatment partially restored neuronal RNA levels. Atropine + 2-PAM prophylaxis eventuated in a complete restoration of RNA levels but no reactivation of AChE. Addition of physostigmine to the atropine + 2-PAM treatment regimen resulted in appreciable AChE reactivation but reduced RNA levels. The overall data indicate that: (1) soman-induced neuronal RNA depletion can be completely reversed by antidotal pretreatments; (2) no precise relationship exists between the extents of antidote-induced restoration of RNA and AChE levels; and (3) 2-PAM exerts marked effects on the brain neuronal network which are unrelated to AChE reactivation. It is postulated that effects of soman and antidotes on neuronal RNA metabolism may signify alterations in acetylcholine (ACh) sensitivity and that pharmacologic manipulation of ACh responsiveness during organophosphate cholinesterase poisoning may be a mechanism for additional therapeutic intervention.

Acetylcholinesterase↗

Comparison of effects of intraoperative and postoperative methadone: acute tolerance to the postoperative dose?

The effects of methadone 10 mg administered in two different clinical contexts, at induction of anaesthesia and following operation, were studied in two groups of patients undergoing elective total hip replacement. The intraoperative group received methadone 10 mg i.v. at induction of anaesthesia as part of a balanced anaesthetic technique. The postoperative group received methadone 10 mg i.v. following operation, extradural bupivacaine being used for the operative period. A demand analgesia system delivering methadone i.v. was used after operation in both groups. Arterial blood-gas tensions, cortisol and glucose concentrations, analgesic effects and plasma methadone concentrations were compared in the two groups. The only major difference between the two groups was in analgesic requirement. At the time of connection to the demand system the two groups had the same plasma methadone concentrations. Subsequently, the postoperative group had a significantly greater analgesic requirement which resulted in significantly greater plasma methadone concentrations the following morning. Thus, the administration of methadone following operation appeared to exert less analgesic effect than the same dose given during operation. The reasons for this are discussed.

Adult↗

Comparison of flupirtine maleate and dihydrocodeine in patients following surgery.

Flupirtine maleate 100 mg was compared with dihydrocodeine 60 mg when given by mouth to 50 women on the first 3 days following abdominal hysterectomy in a double-blind parallel-group trial. The analgesia produced was similar for both preparations, and the consumption of active drug was the same in both groups. The only significant differences in side-effects were an increased frequency of depression in patients receiving flupirtine and of sleepiness in those receiving dihydrocodeine.

Adult↗

A comparison of intramuscular and sublingual buprenorphine, intramuscular morphine and placebo as premedication.

Buprenorphine premedication by two routes, 0.4 mg sublingual and 0.3 mg intramuscular was compared double-blind, double-dummy with intramuscular morphine 10 mg and placebo in 74 patients undergoing elective total hip replacement. Anxiety, depressive mood, sedation, vital signs and side-effects were measured before surgery. All patients then received a standardised general anaesthetic using a muscle relaxant and ventilation. The effects of the premedication on the anaesthetic were assessed by a scoring system. Intra- and postoperative blood gases, plasma cortisol and glucose were measured and the 1 hour postoperative pain intensity, side-effects and sedation were assessed. No differences between the premedications were seen on any of the pre-, intra- or postoperative measurements, suggesting that even with adequate measurement sensitivity it is difficult to distinguish opiate from placebo premedication.

Administration, Oral↗

Increased cortisol excretion in chronic pain.

Urine samples were collected from 67 patients attending a Regional Pain Unit for treatment of chronic pain. Patients treated with steroids or with any signs or symptoms of Cushing's syndrome were excluded. The urine cortisol creatinine ratio was subsequently measured. Values for the urine cortisol/creatinine ratio were elevated in 31% of the patients, and grossly elevated in some. These patients could not be differentiated from those with normal ratios on the basis of pain or mood scores, cause of pain or drug therapy; they tended to have pain of shorter duration. Possible interpretations of these results are discussed.

Chronic Disease↗

Phaeohyphomycosis of brain: granulomatous encephalitis caused by Drechslera spicifera.

Drechslera spicifera is a dematiaceous fungus which occurs widely in nature but only rarely has been implicated in animal and human infections. Previous infections have occurred in superficial and subcutaneous sites or were encountered in immunologically compromised hosts. This report documents a case of granulomatous encephalitis due to Drechslera spicifera in an immunologically competent woman with no known underlying disease, from whom the fungus was isolated. Animal pathogenicity studies in mice reproduced the histopathologic features, and the fungus was reisolated from the animals.

Adult↗

Single-dose comparison of buprenorphine 0.3 and 0.6 mg i.v. given after operation: clinical effects and plasma concentration.

The plasma concentrations and clinical effects of a single i.v. dose of buprenorphine 0.3 or 0.6 mg were studied in patients recovering from surgery. Analgesic and hormonal effects were greater with the greater dose without a parallel increase in respiratory depression. A comparison with previous work suggests that increased efficacy results either from the use of the larger dose or equivalently if the first required postoperative dose of 0.3 mg has been preceded by a similar loading dose.

Aged↗

Dural permeability to narcotics: in vitro determination and application to extradural administration.

The permeability of cranial and lumbar dura to various substances including a number of narcotic analgesics was measured in vitro. Preliminary data On human postmortem material is reported. Permeability had a linear relation to the inverse of the square root of molecular weight. This is the expected relationship for a diffusion process dependent upon molecular weight. The differential mass selectivity coefficients for lumbar and cranial dura were calculated; they were similar at 0.8 and 0.9. This was greater than for diffusion in simple liquids, but much less than that for biological lipid membranes. This suggests that the low rates of diffusion are a property of the thickness of the dura rather than any inherent impermeability. A simple model for the dural transfer of drugs is described, and applied to narcotics. Its purposes were to suggest: the factors involved in the dural transfer of drugs; the physicochemical properties of drugs relevant to their dural transfer; worthwhile measurements in future studies. The model indicates that drug molecular weight and rate of absorption are important determinants of the efficiency of dural transfer. Low molecular weight and slow absorption produce high dural transfers. When applied to narcotics, these factors could produce a difference of up to an order of magnitude in the amount transferred directly across the dura.

Absorption↗

Acute i.v. Methadone Kinetics in Man: relationship to chronic studies.

Twenty-six patients were given methadone 10 mg i.v. to obtain acute human kinetics. Plasma methadone concentrations from separate 3- and 6-h studies were measured by radioimmunoassay. Kinetic parameters derived from triexponential NONLIN analysis showed that T1/2 alpha and T1/2 beta were 2 and 30 min respectively; no reliable estimate for T1/2 gamma could be obtained. The clearance was estimated as 149 /+- 62 and 163 /+- 49 ml min-1 in the 3- and 6-h studies respectively. These values are compared with those published for chronic administration. The difficulties in determining accurate terminal half-life and clearance values from short duration studies are discussed; these difficulties are accentuated by the long terminal half-life of methadone. Appropriate estimates of clearance may be derived from an acute short duration study provided that the average of triexponential fits to individual patients data is used, even when data extend from only 3h. As might be anticipated, no analysis produced appropriate terminal half-life values for this drug.

Adult↗