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Biomedical subjects

G Brock

Publications and source records attributed to G Brock.

45 records · Page 3Linked to original sources
PubMed1989

A review of reduction and internal fixation of adult femoral neck fractures in a county hospital.

Treatment of femoral neck fractures at a county hospital, Parkland Memorial Hospital, Dallas, Texas, from 1978 to 1983 was reviewed. A study of the use of the quadratus femoris muscle-pedicle graft (MPG) as adjunctive treatment to open reduction and internal fixation (ORIF) was in effect during that time. Patients who had primary prosthetic replacement of their femoral head were not included in the study. Two groups of patients were identified, one group that had ORIF without a muscle-pedicle graft (no-MPG) and another group that had ORIF with a muscle-pedicle graft (MPG). There were a similar number of patients in each group (MPG = 25 patients, no-MPG = 24 patients). Although the groups were not exactly similar, the overall outcome was unexpected. The no-MPG group had 76% good-to-excellent results whereas the MPG group had only 24%. A poor result or outright failure of the technique occurred in 68% of the MPG group and in only 16% of the no-MPG group. No accurate assessment of the incidence of avascular necrosis of the femoral head could be made.

Adolescent↗
PubMed1987

Effect of airway wall flexibility on clearance by simulated cough.

In our previous study, we investigated the relationship between mucus rheology, depth of mucus layer, and clearance by simulated cough. The purpose of the present study was to examine the effect of airway wall flexibility on the clearance of mucuslike gels. Transient airflows similar to cough were generated by both positive and negative pressure, the latter to mimic the dynamic compression that occurs during real cough. As in the previous study, the trachea was modeled as a trough of rectangular cross section with only the bottom lined with the mucus simulant. Clearance was followed by observing the displacement of marker particles. Since cough clearance is intimately related to wave formation in the mucus blanket, we hypothesized that clearance might be impeded if the wave formation occurred simultaneously in the wall and its lining layer. Thus, in one set of experiments the bottom rigid surface of the model trachea was replaced with a frame over which a flexible membrane could be drawn, whereas in the other set the rigid top was replaced by the frame. We also examined the effect of negative-pressure cough in excised canine tracheae, comparing the case where the tracheal membrane was free to deform vs. the case where it was secured. For the rigid-walled model, clearance by positive or negative pressure, with matched flow pattern, was the same. With the mucus simulant lining the flexible bottom surface, clearance increased with increasing membrane flexibility for negative-pressure cough and decreased for positive-pressure cough.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Clearance of mucus by simulated cough.

We examined the relationship between mucus rheology, depth of mucus layer, and clearance by simulated cough. A model trachea was constructed of rigid Plexiglas of rectangular cross section (1 X 2 X 35 cm). The bottom of the trachea was lined with mucus simulants, gels prepared from locust bean gum cross-linked with sodium borate. Cough was simulated by opening a solenoid valve connecting the model trachea to a pressurized tank. An upstream flow-constrictive element was used to shape the flow profile of the simulated cough to approximate the pattern seen in a normal adult. Clearance of mucus was quantitated by observing the movement of contrasting marker particles floating in the mucus layer. The median particle displacement per cough maneuver was defined as the clearance index (CI). We found that CI for any initial depth of mucus increased with the driving pressure in the tank. For a given driving pressure, CI increased linearly with increasing mucus depth. For a given driving pressure and depth, CI decreased with increasing mucus cross-link density. For mucus samples with comparable levels of dynamic viscosity, samples with higher elasticity cleared less well. Mucus clearance was associated with transient wave formation in the lining layer.

Cough↗
PubMed1980

Use of a multiple family group for crisis intervention.

This paper describes the ultilization of a multiple family group as a novel crisis intervention technique for the families of hospitalized burn patients following a tank car explosion. The technique combined a multiple family group with an information group model using a multidisciplinary team of liaison psychiatrist, chaplain, social worker, and psychiatric nurse consultant. A brief dicussion of the theoretical model and literature is included, as well as an assessment of the group process, the perspective of the different disciplines involved, and a follow-up report.

Burns, Chemical↗
PubMedDate not supplied

Oral phentolamine (Vasomax).

Vasomax is an oral preparation of phentolamine mesilate (Zonagen Pharmaceuticals) currently undergoing worldwide regulatory approval for distribution. Phentolamine is primarily an alpha-adrenergic antagonist with mild sympatholytic action and a beta-adrenergic stimulating action. Over 30 years of clinical experience has shown it to be a strong direct vasodilator on muscular walled vessels, likely based on its inhibitory action on adenosine 5-triphosphate-sensitive potassium channels. This medication is not new, having been marketed in the United States in an oral formulation between 1952 and 1984. Phentolamine initially achieved FDA approval for preoperative use in patients with pheochromocytoma for control of blood pressure and paroxysmal hypertensive episodes. In the past it had been evaluated for hypertension, pulmonary disease, cardiac arrhythmias, angina pectoris and peripheral vascular disease. Unfortunately for most of these indications the clinical responses to oral phentolamine have been variable. The most clinically significant adverse events associated with oral phentolamine in the past were systemic hypotension and vasomotor collapse, severe gastrointestinal side effects especially diarrhea and some complaints of nasal congestion. In this review we will concentrate on phentolamine in a new preparation for on demand treatment of erectile dysfunction of mild to moderate degrees.

Journal Article↗
PubMedDate not supplied

Sildenafil citrate (Viagra).

Sildenafil citrate, a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type V (PDE V), initially designated as compound 92-480-10 by Pfizer, was studied in the late 1980s as an antianginal. An unexpected side effect of the early clinical investigations was improved erectile function among the men studied. This serendipitous finding has transformed the field of erectile dysfunction therapy (1-3). The novelty of this compound is its oral route of delivery and efficacy across a broad range of etiologies.

Journal Article↗