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Biomedical subjects

G Stone

Publications and source records attributed to G Stone.

53 records · Page 3Linked to original sources
PubMed1985

Comparison of acebutolol and propranolol therapy for ventricular arrhythmias.

The effects of acebutolol, a new investigational cardioselective beta blocker, and propranolol on ventricular arrhythmias were compared in 14 patients with more than 30 premature ventricular contractions (PVCs) per hour. Each patient served as their own control, receiving both drugs and placebo in random sequence and in double-blind fashion, with an intervening one-week, drug-free period. Each drug was given for a two-month period, the maximum acebutolol dosage reaching 600 mg tid and the maximum propranolol dosage 80 mg tid. Seventy-two-hour ambulatory electrocardiographic monitoring assessed arrhythmia frequency for each study period. Mean PVC counts did not significantly differ during the two control periods. Acebutolol decreased mean PVC count by 65% (P less than .02), with eight patients exhibiting a 70% or greater decrease. Only three patients exhibited a similar decline with propranolol. The incidence of PVCs was not significantly decreased by propranolol. Acebutolol reduced the number of couplets by 70% (P less than .04), whereas propranolol did not significantly affect couplets. At the dosage of 600 mg tid, acebutolol was well tolerated, effectively suppressed total PVCs and couplets, and appeared to be more effective than propranolol administered at 80 mg tid.

Acebutolol↗
PubMed1983

CGS 7525A, a new, centrally active alpha 2 adrenoceptor antagonist.

CGS 7525A, a new tetracyclic compound, was evaluated for alpha 2 adrenoceptor antagonism in receptor binding assays and in behavioral and electrophysiological tests. 3H-Clonidine, but not 3H-prazosin, binding was potently inhibited in vitro by CGS 7525A. In vivo, CGS 7525A attenuated the suppressant action of clonidine on phenylquinone-induced writhing and on locus coeruleus neuronal firing rate. Mianserin was nearly equipotent with CGS 7525A in the 3H-clonidine binding assay, but considerably less potent in the measures of alpha 2 adrenoceptor antagonism in vivo. Both CGS 7525A and mianserin displaced 3H-spiroperidol binding from frontal cortex 5-HT2 binding sites. Although yohimbine resembled CGS 7525A in most respects, its activity at 5-HT2 binding sites was relatively low, CGS 7525A was not associated with any appreciable blockade of norepinephrine or serotonin uptake in vitro. Thus, CGS 7525A appears to be a promising new pharmacological tool for investigating the behavioral function of brain alpha 2 adrenoceptors.

Adrenergic alpha-Antagonists↗
PubMed1981

Characterization of [3H]clonidine binding to two sites in calf brain membranes.

Kinetic studies showed that under appropriate conditions, [3H]clonidine binds to two distinct receptor sites in calf cortex membranes. At 23 degrees C, binding was obtained at a low-affinity site (dissociation constant, KD = 5.4 nM) and a high-affinity site (KD = 1.1 nM). In contrast, at 0 degree C, selective binding occurred to the low-affinity site only. Consequently, at 0 degree C, it was possible to evaluate the interaction of drugs with the low-affinity receptor directly. On the other hand, competition with the high-affinity receptor could be ascertained by generating displacement curves representing the differential between specific binding values obtained at 23 and 0 degree C. Guanine nucleotides selectively decreased binding to the high-affinity site without apparent influence on the low-affinity [3H]clonidine binding. The activities of various pharmacological agents at the low- and high-affinity clonidine receptors are discussed and compared with WB-4101 binding data.

Adrenergic alpha-Antagonists↗
PubMed1978

Helping patients to follow their treatment plans.

The optometrist encounters patients who do not adhere or comply with his recommended treatment. This problem of non-adherence adversely affects both the optometrist and the patient. A general framework is presented which the optometrist can use to evaluate his effectiveness at improving adherence. This framework includes problem formulation, joint development of the treatment plan, extended responsibility, and systematic followup.

Humans↗
PubMed1976

Primitive nervous systems: electrophysiology of the pharynx of the polyclad flatworm, Enchiridium punctatum.

1. Electrical activity accompanying motor activity can be recorded from the excised pharynx of Enchiridium punctatum. Multiple stimuli elicit behaviour which consists of an initial aperture closure followed by extension and then peristalsis. If the stimulus parameters are increased the preparation bends from side to side instead of proceeding through the behavioural sequence. Bending appears to inhibit other movements differentially. 2. The conduction involved with peristalsis is polarized and proceeds in a proximal direction. 3. With stimulus intensities greater than those needed to produce the behavioural response an initial muscle potential (IMP) is evoked. The IMP is frequency sensitive. Maximum facilitation occurs within 100 ms and drops to 50% of maximum within 250 ms. 4. Conduction velocities of the IMP range from 0-05 m s-1 to 1-9 m s-1. Conduction velocities appear to increase with facilitation.

Animals↗
PubMedDate not supplied

Student perspectives on problem-based learning in an occupational therapy curriculum: a multiyear qualitative evaluation.

OBJECTIVES: Problem-based learning (PBL) is increasingly being used within health care professional educational programs to develop critical thinking skills via a learner-centered approach. However, few studies have evaluated the effect of participation in a PBL-centered curriculum on occupational therapy knowledge and skill development over time from the perspective of the students involved. This study examined student evaluations of the first three class cohorts participating in a PBL-based curriculum. METHOD: A participatory action design study involving qualitative, student-led focus groups was conducted with 154 students across 2 years of the education program. Fourteen focus groups were audiotaped, and those audiotapes were transcribed by an outside expert, followed by two levels of analysis by program faculty members and a member check by student participants. RESULTS: Themes that emerged from the data analysis related to (a) defining elements of PBL, (b) the role of students and faculty members, (c) learning strategies used by students in a PBL versus traditional education program, (d) the challenges of a PBL approach, and (e) PBL's relationship to clinical reasoning and occupational therapy practice. CONCLUSIONS: Students perceived that a PBL approach adopted consistently across the curriculum contributed to the development of information management, critical reasoning, communication, and team-building skills; however, identified challenges were time and role management, information access, instructor versus PBL expectations and practices, and coping with the ambiguity of knowledge and reasoning.

Adult↗
PubMedDate not supplied

High expression of multinucleated giant cells in cultures of peripheral blood cells from HIV infected patients.

Multinucleated giant cells (MGCs) were detected in cell lines established from peripheral blood lymphocytes of patients with: (a) acquired immunodeficiency syndrome (AIDS) and lymphadenopathy syndrome (LAS), (b) chronic active hepatitis (CAH), (c) papular acrodermatitis (PA) negative for hepatitis B virus antigens but positive for EBV, and (d) epidermolysis bullosa acquisita positive for EBV. All the cell lines established, including those established from AIDS and LAS patients, were examined for the presence of human immunodeficiency virus (HIV) by indirect immunofluorescence with monoclonal antibodies directed against the HIV antigens p17 and p24 and for the presence of reverse transcriptase. All the cell lines were found to be negative for HIV. While the cell lines obtained from AIDS patients still express MGCs after more than two years in culture, their supernatants are negative for reverse transcriptase activity and carry phenotypic markers characteristic of B cells. From the LAS and chronic active hepatitis patients we obtained a monolayer of adherent cells almost completely represented by MGCs that lasted for six and four months, respectively. After this period of time a proliferation process took place. Both the cell lines obtained carry B cell phenotypic markers, but MGCs are still a characteristic only for the LAS-derived cell culture. Non infected patients or normal subjects express MGCs only during the early stage of the cultue. The correlation between the presence of MGCs and a retrovirus infection is discussed in the light of the role of MGCs in the pathogenesis of AIDS.

Cell Line↗