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Biomedical subjects

R Long

Publications and source records attributed to R Long.

At least 73 records · Page 4Linked to original sources
PubMed1987

The effects of indomethacin on edema and gas exchange in canine acid aspiration.

Previous studies have suggested that prostaglandin synthesis inhibition might alter lung water accumulation in low pressure pulmonary edema. Therefore we studied the effects of indomethacin administration on edema formation, hemodynamics, and gas exchange in canine acid aspiration. Fourteen pentobarbital anesthetized dogs received 1 ml/kg of 0.1 N HCl intratracheally and then 7 received indomethacin (5 mg/kg) and 7 served as time controls. Lung liquid was measured in vivo by a double indicator technique and at the end of the experiment by gravimetric determinations. Following HCl administration, venous admixture (Qva/Qt) increased in both groups. Over the succeeding 4 h Qva/Qt decreased after indomethacin administration by 4.1 +/- 14.2%, but increased in the control group by 10.9 +/- 11.5% (P less than 0.05). Cardiac index remained constant in the control group but decreased after indomethacin from 232 +/- 89 ml X kg-1 X min-1 to 167 +/- 75 ml X kg-1 X min-1. Lung liquid accumulation, however, was similar between both groups. We believe that the changes in Qva/Qt associated with indomethacin can be explained by the known observations that decreases in cardiac output are associated with decreases in intrapulmonary shunt.

Analysis of Variance↗
PubMed1986

Hôpital Albert Schweitzer and the Republic of Haiti.

The Hôpital Albert Schweitzer was established near the village of Deschapelles in Haiti in 1956 by Dr. and Mrs. William Larimer Mellon of Arizona. The hospital currently has 162 acute care beds and provides inpatient and outpatient services to a district of about 160,000 people. In 1983, visits to the hospital and its dispensaries totaled 39,163. Since its founding the hospital has evolved into a tertiary care facility but has also established primary care programs through seven satellite dispensaries. Health agents and midwives play an important role in the hospital's field programs. Outreach programs concentrate on health and nutrition education, immunizations, supplementary food programs, tuberculosis screening, oral rehydration for infants with diarrheal diseases and cord cutting clinics for the prevention of neonatal tetanus. This paper describes the principal causes of morbidity and mortality in this area of Haiti, the functioning of the hospital and both its medical and non-medical programs. The latter include agricultural irrigation and well digging projects, and wood working, weaving and ceramic facilities to encourage local artisans.

Community Health Services↗
PubMed1986

Artificial ventilation of a canine model of bronchopleural fistula.

The authors studied the abnormalities of gas exchange and lung mechanics in a canine model of bronchopleural fistula during intermittent positive pressure ventilation (IPPV) and high-frequency oscillatory ventilation (HFOV). The left lower lobe bronchus was opened to atmosphere and it was determined that end expired volume was best maintained at frequencies of 45-50 breaths/min. during IPPV. Comparing alternating periods of IPPV and HFOV in six dogs (Group I) at matched airway opening pressure (Pao), we found that Pao2 decreased significantly to 68 +/- 14 mmHg and 69 +/- 24 mmHg, respectively, on opening the fistula. In a second group of six dogs (Group 2), when Pao was increased by additional bias flow into the ventilatory circuit during both IPPV and HFOV, Pao2 increased significantly to 89 +/- 12 mmHg and 87 +/- 8 mmHg, respectively. Repeating Group 2 studies after induction of oleic acid low-pressure pulmonary edema demonstrated that conventional IPPV was associated with large intrapulmonary shunts. HFOV, however, maintained gas exchange at near baseline values. For both Group 1 and Group 2, the calculated gas flow through the fistula was significantly less at all levels of airway pressure during HFOV. The authors conclude that HFOV offers advantages over conventional IPPV in the maintenance of oxygenation and in the reduction of gas leak through the fistula.

Animals↗
PubMed1985

The effects of surgical and chemical lesions on striatal [3H]threo-(+/-)-methylphenidate binding: correlation with [3H]dopamine uptake.

The specific binding of [3H]threo-(+/-)-methylphenidate to membranes prepared from rat striatum was significantly reduced following either surgical lesions of the medial forebrain bundle or intracerebroventricular administration of 6-hydroxydopamine. The decrease in the density of [3H]threo-(+/-)-methylphenidate binding sites in striatum following chemical or surgical denervation was highly correlated with the decrease in [3H]dopamine uptake. In contrast, intracerebroventricular administration of 5,7-dihydroxytryptamine, AF64A, or chronic parenteral administration of reserpine did not alter either the number of apparent affinity of [3H]threo-(+/-)-methylphenidate binding sites. These data suggest that the specific binding sites for [3H]-threo-(+/-)-methylphenidate in striatum are localized to dopaminergic nerve terminals, and may be associated with the dopamine transport complex.

5,7-Dihydroxytryptamine↗
PubMed1984

Repair of urinary tract fistulas with bulbocavernosus myocutaneous flaps.

Urinary tract fistulas resulting from severe trauma or pelvic irradiation are often associated with extensive tissue loss, scar formation, and fibrosis. Two cases, one with a urethro-vaginal fistula secondary to trauma and one with a vesico-vaginal fistula secondary to irradiation, are presented. In neither case could the bladder, urethra, or vagina be repaired primarily. Using a bulbocavernosus myocutaneous "island" flap, the fistulas were successfully repaired. The anatomy of the graft and the operative procedure are described. This new procedure should be considered in urinary tract fistulas in which there is extensive tissue loss and scarring.

Adult↗
PubMed1983

Role of nitrosation in the mutagenic activity of coal dust: a postulation for gastric carcinogenesis in coal miners.

The mutagenicity of coal dust solvent extracts with and without nitrosation was studied using the Salmonella/microsome assay system. Coal dust solvent extracts were either non-mutagenic or very weakly mutagenic with S9 activation. High mutagenic activities, however, were found when extracts of bituminous, subbituminous, and lignite coal dusts were reacted with nitrite under an acidic condition. Formation of mutagens from coal dust extracts by nitrosation was highest at pH 3.2 and decreased with increasing pH in the reaction mixture. Mutagenic activity appeared to be independent of metabolic activation. The mutagens formed from nitrosation of coal dust extracts induced frameshift mutations. The results reported here may have possible implications for the explanation of an elevated incidence of gastric cancer in coal miners.

Coal↗
PubMed1982

Upper extremity neuropathies following median sternotomy.

The status of 958 patients who underwent median sternotomy between January, 1978, and May, 1981, was analyzed. Fifty-four patients had an upper extremity neuropathy. Among 38 patients who underwent further evaluation, motor and sensory nerve conduction studies localized the injury to the level of the elbow in 13, to the brachial plexus in 10, and to both locations in 6. Ninety-two percent of these 38 patients were asymptomatic 3 months after operation.

Arm↗
PubMed1981

Intractable diarrhoea in a patient with vasoactive intestinal peptide-secreting neuroblastoma. Attempted control by somatostatin.

A 1 1/2 year old child developed profuse watery diarrhoea, shown to be due to excessive plasma vasoactive intestinal peptide (VIP) levels, whilst on treatment for metastatic neuroblastoma. Because it was unresponsive to alternative treatment, an attempt was made to control the diarrhoea with a somatostatin infusion. The attempt failed despite the fact that serum VIP levels were substantially reduced. Possible reasons for failure are discussed and the importance of plasma VIP as a marker for maturation in neuroblastoma emphasised.

Diarrhea↗
PubMed1981

Lack of difference in digoxin urinary excretion with two intravenous infusion rates.

Ten normal subjects were given 0.4 mg digoxin intravenously by bolus injection over 3 to 5 min and by constant-rate infusion for 1 hr. Urinary excretion of digoxin over the next 6 days, as measured by radioimmunoassay, was similar after both the rates of intravenous injection. In one subject, who excreted substantial amounts of digoxin reduction products, no difference was apparent in the amount of reduced metabolites excreted. These results are not in agreement with previous reports of an effect of intravenous infusion rate on urinary digoxin excretion.

Adult↗