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Biomedical subjects

R D Miller

Publications and source records attributed to R D Miller.

At least 163 records · Page 9Linked to original sources
PubMed1990

American forensic psychiatrists who work in state institutions.

The authors surveyed a sample of American forensic psychiatrists who work in state institutions. As a group, their respondents tended to be middle-aged, white men, who had little formal training in forensic psychiatry, felt somewhat alienated from their peers, yet who were Board certified in general psychiatry. They tended to be involved primarily in the direct treatment of patients, and most often expressed concerns about the care-and prominent lack of aftercare--received by forensic patients. They also perceived a sense of patient futility in the institutional forensic setting. The authors conclude by recommending that AAPL take a more active role in appealing to and representing such forensic psychiatrists.

Adult↗
PubMed1989

Recent developments in antitrust: challenges to medical autonomy.

Once exemptions from antitrust scrutiny were removed, economic arguments have proved effective in dissolving the hegemony formerly held by psychiatrists over the provision of mental health services. A growing number of courts, legislatures, and insurance companies have been persuaded by psychologists that they can provide at least comparable services at lower costs than psychiatrists. The fact that psychotherapy is less obviously a "medical" procedure than surgery or other physical treatments has facilitated the establishment of the psychologists' position. After these gains, there are indications that other mental health providers will follow the paths established by psychologists. Cost-containment efforts in the mental health care industry, particularly through health maintenance organizations, have already led to increased utilization of nondoctoral providers for initial screening services, and psychiatrists have even filed countersuits alleging restraint of their trade through the exclusive use of lower-cost providers (State Medical Society of Wisconsin v. Schweiker et al., 1982). With the clear message from many courts and legislatures that profession will no longer serve to distinguish among mental health providers, it appears that the validity of psychiatrists' assertions that independent practice by nonmedical mental health professionals will result in lower quality of care for patients will be tested in the marketplace, with peer review and tort litigation serving as the barometer by which that quality will be measured. And, as other nonmedical professionals establish their credentials through licensure and recognition by consumers, we can expect that they will also seek recognition of their capacities to provide (and be reimbursed for) professional services through the courts. With this greater access to consumers of mental health care will also come, of course, greater public scrutiny and greater risk of malpractice liability.

Allied Health Personnel↗
PubMed1989

Comparison of the neuromuscular block induced by mivacurium, suxamethonium or atracurium during nitrous oxide-fentanyl anaesthesia.

We compared the neuromuscular and cardiovascular changes following administration of mivacurium 0.15, 0.20 and 0.25 mg kg-1, suxamethonium 1.0 mg kg-1 or atracurium 0.5 mg kg-1 i.v. in 41 (ASA physical status I or II) patients during nitrous oxide-fentanyl anaesthesia. Mean onset times for total ablation of twitch response for mivacurium 0.15, 0.20 and 0.25 mg kg-1, were 2.5, 2.4 and 2.7 min, respectively, similar to that for atracurium (2.5 min), but longer than for suxamethonium (1.1 min) (P less than 0.05). Mean times from administration of drug until twitch response recovered to 10% of control were shorter for each dose of mivacurium (15.6, 18.0 and 20.6 min, respectively) than for atracurium (40.0 min) and longer than for suxamethonium (7.7 min) (P less than 0.05). Mean infusion rate required to maintain twitch response at 5 +/- 4% control was 6.7 micrograms kg-1 min-1 for mivacurium and 6.3 micrograms kg-1 min-1 for atracurium. Following neostigmine 0.045 mg kg-1, mean times for twitch tension to recover from 10% to 90% of control were similar for mivacurium (9.7 min) and atracurium (10.5 min). Transient decreases in mean arterial pressure (greater than 20%) were observed in seven of 15 patients who received the two higher doses of mivacurium.

Anesthesia, General↗
PubMed1989

Modification of central nervous system effects of laudanosine by inhalation anaesthetics.

To determine the effect of inhalation anaesthetics on the plasma concentration of laudanosine necessary to produce CNS excitation, we administered laudanosine 0.5 mg kg-1 min-1 i.v. to 40 rabbits under eight study conditions: 1.0 or 0.7% halothane, 1.6% isoflurane, 2.0% enflurane, during normocapnia and hypocapnia; 70% nitrous oxide, alone and with 1.0% halothane, and room air (control). At the onset of purposeless, unco-ordinated movements of the entire body, blood samples were obtained to determine the CNS excitation-threshold plasma concentration (ETPC) of laudanosine. During normocapnia, 1.0% halothane, 1.6% isoflurane and 2.0% enflurane increased ETPC (mean (SD) 11.8 (2.5), 11.3 (2.8) and 9.1 (1.4) micrograms ml-1, respectively) from control (5.0 (0.9) microgram ml-1). ETPC during enflurane anaesthesia did not change significantly with hypocapnia. Nitrous oxide, alone or in combination with halothane, did not change ETPC. The combination of nitrous oxide with 1.0% halothane significantly decreased ETPC to less than that for halothane alone (6.7 (1.2) v. 11.8 (2.5) micrograms ml-1, respectively).

Anesthesia, Inhalation↗
PubMed1989

The influence of renal failure on the pharmacokinetics and duration of action of pipecuronium bromide in patients anesthetized with halothane and nitrous oxide.

The authors determined the pharmacokinetics and duration of action of a bolus dose of pipecuronium bromide (0.07 mg.kg-1) in 40 patients anesthetized with halothane and nitrous oxide. Twenty were patients with normal renal function, undergoing a variety of surgical procedures, and 20 were undergoing cadaver renal transplantation because of end-stage renal disease. Plasma concentrations of pipecuronium were measured for 6 h after administration using a sensitive and specific capillary gas chromatographic assay. Plasma concentration versus time data were analyzed by nonlinear regression and fit to a two-compartment or three-compartment model; in addition, the data were analyzed by a non-compartmental method based on statistical moments. Neuromuscular blockade was assessed by measuring the mechanical evoked response of the adductor pollicis muscle to train-of-four stimulation of the ulnar nerve. The pharmacokinetic parameters derived by compartmental modelling were (normal vs. renal failure, respectively): volume of distribution at steady state (309 +/- 103 vs. 442 +/- 158 ml.kg-1, mean +/- SD), plasma clearance, (2.4 +/- 0.6 vs. 1.6 +/- 0.6 ml.kg-1.min-1), mean residence time (140 +/- 63 vs. 329 +/- 198 min), and elimination half-life (137 +/- 68 vs. 263 +/- 168 min). The same parameters as derived by the non-compartmental method were (normal vs. renal failure, respectively): volume of distribution at steady state (307 +/- 80 vs. 426 +/- 119 ml.kg-1, mean +/- SD), plasma clearance (2.4 +/- 0.6 vs. 1.6 +/- 0.6 ml.kg-1.min-1), mean residence time (134 +/- 41 vs. 323 +/- 228 min), and elimination half-life (118 +/- 35 vs. 247 +/- 168 min).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

The dose-response relationship of mivacurium chloride in humans during nitrous oxide-fentanyl or nitrous oxide-enflurane anesthesia.

The dose-response relationships of mivacurium chloride during N2O/fentanyl or N2O/enflurane anesthesia were compared in 70 patients intraoperatively. Responses were defined in terms of percentage changes in the evoked twitch tension of the adductor pollicis muscle, and dose-response curves were constructed following probit transformation of the responses. End-tidal concentrations of enflurane during the were study were 0.9-1.2%. When compared with the dose-response curve determined during N2O/fentanyl anesthesia the curve determined during N2O/enflurane anesthesia was displaced significantly to the left (P less than 0.05). As a result, the doses of mivacurium that depressed twitch tension by 50% (ED50) and 95% (ED95) were 39 and 67 micrograms/kg, respectively, during N2O/fentanyl anesthesia, and 27 and 52 micrograms/kg during N2O/enflurane anesthesia. Regression lines describing the relationship between the maximum depression of twitch tension (response) and the time interval between the injection of mivacurium and the return of twitch tension to 90% of the control value (duration) were constructed. The response-duration line for N2O/enflurane anesthesia was displaced significantly to the left of the line for N2O/fentanyl (P less than 0.05), indicating that enflurane anesthesia was associated with a prolongation of mivacurium-induced neuromuscular blockade. The neuromuscular blocking effect of mivacurium is both enhanced by and prolonged during N2O/enflurane compared with that during N2O/fentanyl anesthesia.

Anesthesia, General↗
PubMed1989

Atracurium, vecuronium, and pancuronium do not alter the minimum alveolar concentration of halothane in humans.

The authors studied 64 unpremedicated, healthy surgical patients, aged 42 +/- 14 yr, to determine the effects of atracurium, vecuronium, and pancuronium on the minimum alveolar concentration (MAC) of halothane. Anesthesia was induced using halothane/nitrous oxide/oxygen via a mask without the administration of other drugs. Nitrous oxide was discontinued, the trachea was intubated without prior administration of neuromuscular blocking drugs, and anesthesia was maintained with halothane in oxygen. Participating patients were assigned to one of five groups: 1) no neuromuscular blocking drug (control group, n = 9); 2) atracurium 0.5 mg/kg (n = 10); 3) atracurium 1.0 mg/kg (n = 15); 4) vecuronium 0.1 mg/kg (n = 20); or, 5) pancuronium 0.1 mg/kg (n = 10). Tourniquets, inflated to 300 mmHg immediately before iv administration of neuromuscular blocking drug and 15-30 min prior to skin incision, were used to isolate extremities from circulating neuromuscular blocking drug in all patients. A positive response to stimulation was defined as movement of at least one extremity occurring distal to the tourniquet within 1 min following skin incision. The first patients in the control and atracurium groups were studied at an end-tidal halothane concentration of 0.95%. The first patient in the pancuronium group was studied at a halothane concentration of 0.75%, and the first patient in the vecuronium group at 0.70%. Subsequent patients were studied at end-tidal halothane concentrations 0.10% above or below that of the preceding patient, depending on the presence or absence of movement with skin incision. Control MAC for halothane was 0.74% +/- 0.09% (mean +/- SEM).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

The relationship between adductor pollicis twitch tension and core, skin, and muscle temperature during nitrous oxide-isoflurane anesthesia in humans.

Temperature and volatile anesthetic agents influence neuromuscular transmission. Because mild hypothermia is common during general anesthesia, the authors sought to determine the relationship between the core temperature, adductor pollicis muscle temperature, and the twitch response of the adductor pollicis muscle, during isoflurane anesthesia in 15 patients undergoing elective surgery in which muscle relaxants were not required. Five patients were allowed to cool spontaneously, five were cooled actively, and normothermia was maintained actively in the remaining five. In the normothermic patients (core greater than 36.5 degrees C, muscle greater than 35.7 degrees C), the twitch response of the muscle remained unchanged from control values. In the patients who were cooled passively or actively, a muscle temperature threshold was observed (35.2 degrees C), below which twitch response of the muscle diminished by 10-15%/degrees C decrease in muscle temperature. To ensure that the adductor pollicis muscle temperature remained above 35.2 degrees C, the core temperature had to be maintained above 36 degrees C. A significant linear relationship (P less than 0.05) was found between the adductor pollicis muscle temperature and twitch tension below the threshold for each individual patient in the cooled groups (correlation coefficient range, 0.80-0.99). Thus, there is a temperature-related decrease in adductor pollicis twitch response during isoflurane anesthesia, and the temperature of this muscle should be maintained above 35-35.5 degrees C during studies of neuromuscular transmission. This can be achieved by maintaining core temperature above 36 degrees C.

Anesthesia, Inhalation↗
PubMed1989

Pharmacokinetics and disposition of pipecuronium bromide in dogs with and without ligated renal pedicles.

The pharmacokinetics of pipecuronium bromide have been studied in anesthetized beagle dogs with and without ligated renal pedicles. A gas chromatographic assay was used to measure the plasma, urine, bile concentrations, and liver content of pipecuronium, the later of which was obtained 8 h after injection. Following an iv bolus injection of 0.1 mg/kg, pipecuronium disappeared from the plasma exponentially with distribution half-lives of 3.9 +/- 1.1 min and 12.7 +/- 9.5 min (mean +/- SD), and elimination half-lives of 44.8 +/- 2.6 min and 196.7 +/- 102.0 min in animals with and without renal pedicle ligation, respectively. Except for the volume of central compartment, all other pharmacokinetic variables differed significantly between the two experimental groups. The elimination half-life was longer (196.7 +/- 102 (SD) vs. 44.8 +/- 2.6 min), plasma clearance slower (5.9 +/- 0.8 ml.kg-1.min-1 vs. 0.9 +/- 0.1 ml.kg-1.min-1) and mean residence time longer (221 +/- 73 vs. 51.1 +/- 1.8 min) in dogs with ligated renal pedicles. Eight hours after injection, the recovery of the parent form of pipecuronium approximated 77% of the administered dose in the urine, 4.5% in the bile, and 3.3% in the liver of normal animals. In animals with ligated renal pedicles 16% of the unchanged pipecuronium was excreted into the bile and 10% of the administered dose was recovered from the liver. Since the total recovery of unaltered pipecuronium approximated 85% of the administered dose in the intact animals, biotransformation seems to play an insignificant role in disposition of this new neuromuscular blocking drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Androstane-3,17-diol↗
PubMed1989

Bactericidal effect of lactoferrin on Legionella pneumophila: effect of the physiological state of the organism.

Lactoferrin has been previously shown to be bactericidal for Legionella pneumophila. The current study showed that CaCl2, Mg(NO3)2, and MgCl2, but not NaCl, blocked killing. Activity was pH dependent with the greatest activity at 5.0. Sensitivity of the organism was dramatically affected by the growth conditions. Log phase 12 h, broth-grown cells were most sensitive, with older cultures becoming more resistant. Plate-grown cells were completely resistant. Lactoferrin binding, as detected by immunofluorescence microscopy, was temperature dependent (no binding at 4 degrees C), but was independent of killing.

Calcium Chloride↗
PubMed1989

Provisional restorations in fixed partial prosthodontics.

Concepts and techniques for fabrication of various types of provisional fixed restorations have been described. The problems created by less than optimal construction are presented. The clinician must decide which type of fixed provisional appliance is desirable or required in various situations. The same fixed provisional restoration cannot be suitable in every situation. The dentist must be able to evaluate and select which type of interim fixed prosthesis should be constructed for the various cases that present in their offices.

Denture Design↗
PubMed1989

Dental implants and third party carrier coverage.

In the exciting arena of successful dental implantology, we can only anticipate improvement and overall progress. For the dentists who have the opportunity to participate and share their skills with the public, it is hoped that such services will be uniformly accepted by third-party insurers. Training in implant construction is currently being incorporated into both predoctoral and postdoctoral curricula. According to Worthington, it is estimated that by 1992, 300,000 implants will be used per year in the United States, and that there will be a fall in the average cost of each implant. The problems of financial underwriting are at present complicated and somewhat ambiguous. It is hoped that these problems will be resolved by conferences of national representation of dentistry, medicine, and insurance carriers. At present, however, it is a vital problem, and every practitioner in the field of dental implantology should consider his or her role in urging recognition and reimbursement of a covered service.

Dental Implantation, Endosseous↗
PubMed1989

Should forensic patients be informed of evaluators' opinions prior to trial?

There are several articles in the literature that discuss the problems which occur when persons who have been evaluated by forensic clinicians hear the results of those evaluations for the first time in court. The authors agree that the scenarios presented are problematic but suggest that in many cases the problems can be avoided by sharing the information with the person prior to presenting it in court. They present several case examples to illustrate their point.

Commitment of Persons with Psychiatric Disorders↗