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Biomedical subjects

R Long

Publications and source records attributed to R Long.

At least 91 records · Page 5Linked to original sources
PubMed1989

Tuberculous pericarditis: long-term outcome in patients who received medical therapy alone.

A conservative approach to operative intervention in the treatment of active tuberculous pericarditis was adopted and only 4 of 16 consecutive patients underwent pericardiectomy, all within 2 months of diagnosis. One patient died of constrictive pericarditis despite pericardiectomy, and one died of acute bronchopneumonia after 8 months of otherwise successful medical management. All 14 long-term survivors were reevaluated to exclude chronic constrictive pericarditis and other potential sequelae of tuberculous pericarditis. Reevaluation included physical examination, chest radiograph, electrocardiogram, M-mode and two-dimensional echocardiogram, computed tomography (CT) scan, and in patients less than or equal to 75 years of age, incremental cycle exercise to maximum oxygen consumption. None were found to have chronic constrictive pericarditis or convincing evidence of other recognized complications of tuberculous pericarditis. Our results suggest that when pericardiectomy is not required for the relief of cardiac compression during the acute phase of tuberculous pericarditis and patients are treated with medical therapy alone, an excellent long-term outcome may be anticipated.

Adrenal Cortex Hormones↗
PubMed1989

Serotypes of Pseudomonas aeruginosa from human and animal sources.

Forty human isolates and twenty-eight animal isolates of Pseudomonas aeruginosa from Prince Edward Island area (Atlantic Canada) were serotyped using a kit consisting of 4 polyvalent O-group antisera and 17 monovalent O-type (serovar) antisera, in accordance with the International Antigenic Typing Scheme. The results showed a difference between humans/dogs (50%/48% group I) and pigs (71% group IV). Whereas O-serovar 9 and 1 appeared to be most involved in human and canine infections, O-serovar 3 was the predominant type in porcine infections.

Animals↗
PubMed1989

[Research on the etiology of nasal polyps].

One hundred and seventy patients with nasal polyps were studied. According to the history, skin tests with inhalant allergens, determination of serum nasal secretion and polyp fluid IgE, and X-ray films of nasal sinuses, it was suggested that 93.5% of them might have complicated with allergic diseases, 87.7% with sinusitis. A relationship between local IgE production and the eosinophil infiltration of polyps existed. This study suggests that allergic process acting locally on the mucous membrane of the nose is the etiologic factor and bacterial allergy probably contributes to the development of nasal polyps. In order to prevent the recurrence after polypectomy, antiallergic management combined with antibiotics and drainage of infected sinuses may be necessary in most cases.

Adolescent↗
PubMed1988

Anatomical analysis of frontal cortex sites at which carbachol induces motor seizures in the rat.

High amplitude spiking representative of seizures, accompanied by an unusual motor behavior pattern of rearing and forelimbic clonus resembling "boxing," was elicited by microinjection of the cholinergic agonist, carbachol, 4 micrograms, into the medial prefrontal cortex of the rat. A rating scale devised to score the behavior revealed a motor pattern elicited by carbachol from the medial anterior cortex which was similar to that described by Racine for electrical stimulation of the amygdala. Topographical analysis of the areas surrounding the medial anterior cortex region revealed that the motor manifestations of seizures were elicited over a wide region of the anterior cortex, with scores significantly lower at carbachol microinjection sites greater than 1 mm rostral, 2 and 3 mm caudal, and 2 mm lateral to the standard medial prefrontal cortex site. Unilateral microinjection of carbachol yielded motor seizures primarily from the contralateral forepaw, suggesting involvement of a crossed pathway. Retrograde tracing with fast blue dye, combined with immunostaining for choline acetyltransferase and NADPH-diaphorase, found that the cholinergic neurons innervating the standard microinjection site were the dorsolateral tegmental cells, as previously reported, which have been shown to also contain substance P and corticotropin releasing factor. In addition, cholinergic neurons of the nucleus basalis of Meynert region were found to innervate the standard microinjection site. These findings implicate cholinergic innervation of the rostral cortex in classical limbic seizures.

Animals↗
PubMed1988

Treatment of canine aspiration pneumonitis: fluid volume reduction vs. fluid volume expansion.

The aspiration of gastric acid causes pulmonary edema and hypoxemia. One approach to the management of this syndrome is to raise cardiac output (Qt) and O2 delivery (QO2) to ensure tissue oxygenation (VO2) at the risk of increasing the edema. Another approach reduces the edema by reducing pulmonary microvascular pressure (Pmv) at the risk of reducing QO2 and VO2. We compared these approaches in 24 anesthetized, ventilated dogs with pulmonary wedge pressure (Ppw), a clinical approximation of Pmv, of 12.5 mmHg. Before and again 1 h after endobronchial instillation of 0.1 N HCl, we measured Qt, QO2, VO2, venous admixture, and in vivo extravascular lung liquid. The dogs were then randomly divided into four equal groups: 1) 12.5 mmHg Ppw, high Qt; 2) 7.5 mmHg Ppw, intermediate Qt; 3) 4.5 mmHg Ppw, low Qt; and 4) 4.5 mmHg Ppw plus dopamine, intermediate Qt. Measured values were followed for 4 more h, after which the lungs were excised to compare wet weight-to-body weight ratios (W/B). When plasmapheresis reduced Ppw at 1 h, edema did not increase further and W/B of groups 2 (21 +/- 3), 3 (18 +/- 3), and 4 (22 +/- 3) were significantly less than in group 1 (27 +/- 3) (P less than 0.001). Although Qt decreased with Ppw, increased hematocrit and reduced venous admixture maintained QO2 in group 2 but not in group 3. In group 4 an intermediate Qt maintained QO2 even at 4.5 mmHg Ppw but edema increased to the group 2 level presumably because Pmv rose with Qt on dopamine. VO2 remained constant over time in each group. These data demonstrate that canine HCl-induced pulmonary edema, measured in vivo or gravimetrically, is very sensitive to reductions in Pmv. Moreover, the lowest Pmv (and QO2) was well tolerated because an O2 supply dependency of VO2 was not observed.

Animals↗
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↗