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Biomedical subjects

B J Browne

Publications and source records attributed to B J Browne.

At least 19 recordsLinked to original sources

Selective adrenergic agonists and colon motility in monkeys.

Sympathetic stimulation during and after laparotomy and other surgical procedures may be a factor inducing postoperative ileus. In experiments conducted in fasting monkeys, the effects of the selective sympathetic agonists alpha 1 (phenylephrine), alpha 2 (ST-91), beta 1 (dobutamine), and beta 2 (terbutaline) on colon contractile activity were measured. Strain gauges were implanted on the colon. Recordings were made for 1 hour (control) and then for an additional hour during continuous infusion by one of a range of doses of each drug (experimental). The drug doses were chosen to cover both physiologic and pharmacologic concentrations. All of the sympathetic agonists caused a dose-dependent decrease in the frequency of colon contractions. The beta-agonists did so at a concentration that is sufficiently low to support a hypothesis that beta-stimulation leading to inhibition of smooth-muscle contraction may play an important role in the genesis of postoperative ileus.

Adrenergic alpha-Agonists

Electrical injuries and lightning.

Prolonged cardiopulmonary resuscitation is key to the resuscitation of lightning strike victims. Multiple accounts exist of successful revival of victims thought to be "dead" or in patients who have what is often believed to be unresuscitatable cardiac dysrhythmia. Victims of lightning injury may, in addition to their electrical injury, have secondary injuries that require expedient care if significant morbidity is to be avoided. They should be treated as any victim of trauma, that is, with a complete and thorough evaluation including hospitalization if warranted. In the absence of a cardiac arrest or serious secondary injury, care for the lightning strike victim is generally supportive in nature.

Electric Injuries

Small bowel transplantation promotes bacterial overgrowth and translocation.

Alterations in the symbiotic relationship between immunocompromised hosts and their resident gut microflora may lead to serious complications following small bowel transplantation (SBT). This study examined the effects of SBT and cyclosporine (CsA) immunosuppression on gut bacterial populations and translocation to the mesenteric lymph nodes. Sixty adult male meat-fed Lewis rats were divided into six groups: normal controls, CsA alone (24 mg/kg im qod), CsA carrier vehicle alone, isografts, isografts given CsA, and allografts given CsA. Rats were killed after 3 weeks and segments of small bowel and colon were harvested for quantitative tissue culture. Mesenteric lymph nodes and blood were cultured to identify translocation. Transplantation alone led to an increase in gram-negative aerobes from 2.6 to 4.6 colony forming units/100 mg tissue (P less than 0.05) in the distal ileum (transplanted segment). Eighty-four percent of transplanted animals receiving CsA had bacteria recovered from their mesenteric lymph nodes compared to none in controls (P less than 0.001) and 20% in isografts not receiving CsA (P less than 0.02). Intestinal transplantation alone appears to promote gram-negative overgrowth while the addition of CsA therapy facilitates translocation to the mesenteric lymph nodes and may predispose to gut-associated sepsis following SBT.

Animals

Quantitative serum toxic screening in the management of suspected drug overdose.

Data were collected on 176 consecutive cases of drug overdose evaluated in an emergency department. Quantitative serum toxic screening (TS) was performed for 164 (93%) of these patients; positive results were noted for 133 patients (81%). Six classes of drugs (ethanol, benzodiazepines, salicylates, acetaminophen, barbiturates, and tricyclic antidepressants) were responsible for nearly 70% of all drug detections and were associated with 80% of all admissions in this patient sample. Only two patients (1%) had drug-specific treatment initiated because of TS results. In 12 patients (7%), TS confirmed substances for which specific treatments had been initiated on clinical grounds. Four patients (2%) had drug-specific treatment discontinued because of TS results. Thirty-two patients (19%) were admitted to a medical service; however, only seven patients (4%) were admitted primarily because of TS results. All other patients were admitted because of clinical abnormalities that required inpatient care. It is concluded that only a few drugs are responsible for most drug overdoses. Moreover, TS results rarely change the treatment or disposition of overdose patients; these decisions are typically based on clinical parameters.

Acetaminophen

Late postpartum eclampsia.

A case of new-onset seizures occurring 12 days postpartum is described. The patient presented with headache, hypertension, and proteinuria. Postpartum eclampsia was diagnosed and IV magnesium sulfate was administered. The patient had no further seizures and did not require long-term anticonvulsants. Medical and neurologic evaluations failed to reveal any other etiology for the seizures.

Adult

Esophageal spasm following propranolol overdose relieved by glucagon.

A case of propranolol overdose complicated by esophageal spasm preventing extrication of an orogastric lavage tube and relieved by intravenous glucagon is presented. Esophageal spasm is an infrequent complication of beta-adrenergic over-dose. Possible mechanisms of esophageal spasm and its relief with glucagon are discussed.

Esophageal Diseases

Esophageal obturator airway, ET tube, and pharyngeal-tracheal lumen airway.

Prior to approval of the EOA, this device had not been documented to be effective in oxygenation and ventilation in the pre-hospital arena. The studies quoted to demonstrate its usefulness were done in the very controlled environment of the operating room or of the emergency department. Indeed, the studies on blood gases obtained immediately upon entry into the emergency department would indicate that the esophageal obturator airway is an inadequate and ineffectual pre-hospital airway. The ability of the device to obstruct the esophagus, has been questioned. In a recent review of the EOA, Smith et al state that "How the EOA gained widespread popularity for use in patients requiring CPR without any evidence of its effectiveness is worthy of investigation". The Food and Drug Administration "grandfathered" the EOA as an acceptable device. This approval was to be reviewed with time, and if complications were reported, a second evaluation of the esophageal obturator airway was to be undertaken. Unfortunately, this has never occurred. We are now faced with the pharyngeal-tracheal lumen airway, which is being marketed for use in the pre-hospital area. The Food and Drug Administration approved the marketing and use of this device based on its similarity to the esophageal obturator airway. The PTL, is a device in many respects similar to the EOA. It has been tested in the operating room and the emergency department. In a study done on unsuccessfully resuscitated patients, it was as effective as an ETT. However, no study has shown that the PTL can be used successfully in the pre-hospital setting by ambulance personnel.(ABSTRACT TRUNCATED AT 250 WORDS)

Emergencies

Coronary artery spasm. Part 1: Overview.

The syndrome of coronary artery spasm is described. This phenomenon may occur in conjunction with, or in the absence of, fixed atherosclerotic coronary artery disease. ECG manifestations during an attack mimic those seen with acute myocardial injury, but normalization of the ECG following the resolution of the pain is usual. Intravenous ergonovine is a sensitive and specific test for confirmation of the diagnosis. Nitrates and calcium channel blockers are the mainstay of therapy, although other agents are of theoretical benefit. The role of surgery is unclear.

Angina Pectoris, Variant

Coronary artery spasm. Part II.

Coronary artery spasm can occur in several settings, often combined with coronary artery disease and thrombosis. Calcium channel blockers and beta-blockers are primary treatment modalities. The role of alpha-blocking agents remains unconfirmed.

Adrenergic beta-Antagonists

Some factors influencing the metabolism of benzylamine by type A and B monoamine oxidase in rat heart and liver.

The ability of MAO-A and MAO-B to metabolize benzylamine in vitro has been investigated in mitochondrial preparations from rat liver and heart. Although under normal circumstances benzylamine appeared to be metabolized exclusively by MAO-B in the rat liver, a contribution by both MAO-A and a clorgyline-resistant enzyme component was revealed when the MAO-B activity was much reduced by pretreatment of the mitochondria with appropriate concentrations of deprenyl. These three enzyme activities also contributed to benzylamine deamination in rat heart mitochondria. However, binding studies with [3H]pargyline, which provided an estimate of the respective concentrations of MAO-A and MAO-B active centres in heart mitochondria, indicated a ratio between MAO-A and MAO-B, markedly different from that shown by plots of inhibition of benzylamine metabolism by various concentrations of clorgyline. The interpretation of these clorgyline plots is discussed in terms of the kinetic constants of both MAO-A and MAO-B, and the relative amounts of each enzyme. It is proposed that although the turnover rate constant for benzylamine metabolism by MAO-A is much smaller than that shown by MAO-B, in those tissues containing a large ratio of MAO-A:MAO-B content, the metabolism of benzylamine by MAO-A can be detected.

Amines

Progestational agents and blood coagulation. VIII. Effect of low-dose, alternate-day, estrogen-progestin combinations on blood coagulation factors in man, with a special note on the effect of freezing of blood samples.

Changes in the blood coagulation system were studied in three groups of 20 patients each. The first group received 0.5 mg. of norethindrone daily, plus 0.06 mg. of ethinyl estradiol on alternate days from cycle Day 5 through 25. The second group, all of whom had been fitted with an intrauterine contraceptive device (IUD), received no hormonal treatment and served as a control group. The third group received 0.5 mg. of norethindrone daily, combined with 0.045 mg. of ethinyl estradiol given on alternate days from cycle Day 5 through 25. Blood samples were drawn prior to the initiation of the study and after three months of treatment. Tests of the following parameters of the blood coagulation system were performed: direct platelet count; platelet adhesiveness; prothrombin time; thrombin time; fibrinogen; factor II assay; activity of factors V, VII, VIII, IX, and X; antithrombin III; and fibrin/fibrinogen degradation products. For a number of these factors, both fresh and frozen blood samples were examined. It was concluded that the two treatment regimens, with the use of alternate-day estrogen administration over a three-month period, had no clinically significant effect on the blood coagulation system.

Adolescent

Effect of various estrogen treatment schedules on antithrombin III levels.

Antithrombin III levels were determined in 18 normal indiviuals of both sexes, 24 pregnant women (at term), 20 patients treated with oral contraceptives and 21 postmenopausal patients treated with Premarin. There was no sex difference in antithrombin III levels in the untreated control group. Pregnant women at term had the lowest levels of antithrombin III. The second lowest values were exhibited by women on oral contraceptives. Both of these groups differed significantly (p less than 0.05) from the controls. Premarin treated postmenopausal women had somewhat lower levels of antithrombin III than controls but these were statistically not significant.

Adolescent

Acute cholecystitis in the emergency department.

Acute cholecystitis is a frequent consideration in patients presenting to the emergency department with the challenging complaint of upper abdominal pain. It is estimated that 20% of American adults have gallstones, and of these a large percentage (about one-third) will at some point develop acute cholecystitis. The epidemiology and associated risk factors of acute cholecystitis are briefly reviewed along with the pathogenesis and clinical presentation of the disease. Finally, an approach to the diagnosis in the emergency department and suggested management is discussed including a comparison of the strengths and weaknesses of ultrasonography and hepatobilary scintigraphy.

Acute Disease