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Biomedical subjects

J E Lowe

Publications and source records attributed to J E Lowe.

At least 181 records · Page 10Linked to original sources
PubMed1983

Hypoglycemic seizures in a Shetland pony.

A 12-year-old, 195 kg Shetland pony broodmare had eight seizures between May 29 and August 7, 1979. Plasma glucose levels during three of these seizures were markedly depressed (16, 18 and 19 mg/100 ml). Serum insulin levels were elevated during two of the seizures (86.0 and 97.7 microU/ml). Although a fasting hypoglycemia was not demonstrated, plasma glucose values during a normal day were abnormal; a plasma glucose level of 42 mg/100 ml was noted eight hours post-feeding. Serum insulin values obtained during an oral glucose tolerance test and intravenous glucagon tolerance test were consistent with organic hyperinsulinism of a pancreatic origin. An intravenous glucose tolerance test and a twenty-four hour fast failed to differentiate between the subject and control ponies with respect to plasma glucose and serum insulin levels. Gross and microscopic pathological evaluation of the pancreas revealed a single 2.0 mm adenoma of pancreatic islet cell origin and hyperplasia of islet cells, predominantly beta cells. This is the first report of hypoglycemic seizures in a horse as a result of a pancreatic neoplasm and associated hyperinsulinism.

Adenoma, Islet Cell↗
PubMed1982

Surgical correction of congenital malformations of the coronary circulation.

Although a number of congenital malformations of the coronary circulation have been recognized for many years, only in the recent past have these been diagnosed and surgically corrected. These lesions include origin of the left coronary artery from the pulmonary artery, coronary arterial fistulas, coronary arterial aneurysms, origin of the right coronary artery from the pulmonary artery, and membranous obstruction of the ostium of the left main coronary artery. Specific symptom complexes and complications are apt to be associated with each of these conditions. Coronary arteriography is usually diagnostic, and surgical correction is indicated in many instances to prevent serious and often fatal complications. The clinical manifestations, physical findings, diagnosis, and management of these lesions are reviewed. Fortunately, the surgical results are usually quite good.

Adolescent↗
PubMed1982

Subvalvular thrombotic obstruction of an aortic porcine heterograft.

A 48-year-old man had angina pectoris and symptoms of heart failure. Cardiac catheterization showed severe aortic stenosis and regurgitation, and he underwent aortic valve replacement in 1976 with a 23-mm Carpentier-Edwards aortic porcine heterograft. Initially there was symptomatic improvement, but one year later the patient had the onset of dyspnea and exertional chest pain that became progressively more severe over the next three years. Repeat cardiac catheterization was performed 45 months after valve implantation, and a 76 mm Hg peak to peak and a 44 mm Hg mean systolic gradient across the aortic bioprosthesis were recorded. The porcine heterograft was surgically explanted and found to be obstructed by a subvalvular thrombus that appeared to arise from the junction of the aortic and mitral valve annuli.

Aortic Valve↗
PubMed1982

The role of bronchoplastic procedures in the surgical management of benign and malignant pulmonary lesions.

Conservative pulmonary resection is appropriate for the majority of patients with endobronchial neoplasms of low-grade malignant potential in the proximal airways and for a small but significant number of patients with carcinoma. A portion of the bronchus is removed, with or without lobectomy, as a sleeve resection and a primary bronchial reanastomosis is performed to preserve ventilatory function. Bronchoplastic techniques can also be used to repair traumatic airway injuries and benign strictures. The present series of bronchoplastic procedures consists of 28 patients undergoing operation with pathological diagnoses of carcinoma in 20, adenoma in six, hamartoma in one, and a post-traumatic laceration in one. There were minimal morbidity and no deaths. From 1947 to 1981 a total of 565 bronchoplastic procedures have been reported in the literature. Of these, 504 were sleeve resections for carcinoma. The remaining 61 bronchoplastic procedures were for either excision of endobronchial adenomas or repair of airway injuries of strictures. It appears that bronchoplastic procedures are the ideal surgical therapy for benign endobronchial lesions, tumors of low-grade malignant potential, such as adenomas, and for repair of airway injuries. This approach is also applicable to a select group of patients with carcinoma of th lung, and long-term survival periods comparable to those achieved by pneumonectomy can be demonstrated.

Adenoma↗
PubMed1982

Retropulsion-propulsion in equine large colon.

The circular and longitudinal muscle coats of equine "midcolon" were found to be directly electrically coupled. They appear to act in concert, in healthy animals, as a pacemaker in the area of the large colon pelvic flexure, for retropulsive-propulsive myoelectrical events. The retropulsive events keep the cecum and right ventral and left ventral divisions of the colon filled, imposing a delay time for fermentation of cellulose and for bacterial protein synthesis. Point-to-point involvement of adjacent colon sections was slowed by cooling the intestinal contents with no adverse clinical signs. Diminution of the blood flow to this regulatory area was achieved in 12 weanling foals (raised parasite-free) by parasitic cranial mesenteric arteritis, using Strongylus vulgaris larvae. Four of the 12 developed clinical signs of abdominal pain, but on necropsy 3 of these 4 had no gross lesions in the gastrointestinal tract. Dissociation of the left ventral and left dorsal colon divisions, as regards intraluminal pressure events and their antecedent myoelectrical action potentials, was induced in 7 of 8 adult animals given an acaricide which under field conditions is associated with progressive large colon obstruction and colic.

Animals↗
PubMed1981

Influence of dietary molybdenum on copper metabolism in ponies.

The effects of molybdenum ingestion on copper metabolism were investigated in bile duct-cannulated ponies fed diets containing 1.01, 27.4 and 107.3 ppm molybdenum. Copper metabolism was assessed by examination of 64Cu and stable copper excretion in feces, bile and urine. The addition of molybdenum to the diet decreased copper absorption and retention as a consequence of increased excretion of dietary copper in feces and increased excretion of absorbed copper in bile. Only 5% or less of the absorbed copper was excreted in urine regardless of dietary treatment. Biliary molybdenum excretion was only 0.86 mg per 100 kg of body weight per day even when ponies were fed the highest level of molybdenum. However, increased molybdenum ingestion produced elevations in protein bound copper in bile. Molybdenum was absorbed by ponies but urinary excretion was effective in eliminating most of the element from the body.

Animals↗
PubMed1981

Surgical management of congenital coronary artery fistulas.

Congenital fistulas are the most common of the coronary arterial malformations and with the widespread use of selective coronary arteriography are being recognized with increasing frequency. Twenty-eight patients with congenital coronary fistulas have been evaluated at the Duke University Medical Center between 1960 and 1981. An additional 258 patients have previously been reported in the literature, making a total of 286 available for review. The right coronary artery is most commonly involved, and the fistulous communication is most often to the right ventricle, right atrium or pulmonary artery. Slightly more than half of the patients with coronary fistulas are symptomatic at the time the diagnosis is made. Surgical correction is strongly recommended to prevent the development of congestive heart failure, angina, subacute bacterial endocarditis, myocardial infarction, and pulmonary hypertension, as well as coronary aneurysm formation, with subsequent rupture or embolization. There were no operative or late deaths in the patients who underwent operations. Moreover, there have been no recurrent fistulas during a mean follow-up period of ten years. The risks of operative correction appear to be considerably less than the potential for development of serious and potentially fatal complications, even in asymptomatic patients.

Adolescent↗
PubMed1981

Effects of oxygen toxicity on regional ventilation and perfusion in the primate lung.

Since the effect of prolonged exposure to high concentrations of oxygen on regional ventilation and perfusion has not been previously, a reproducible primate model of oxygen toxicity was developed to investigate the pathophysiologic changes that occur. Regional ventilation and perfusion were measured by 133Xe techniques in 10 baboons before and after 108 hours of continuous exposure to an inspired oxygen concentration of more than 90%. Arterial blood gases, shunt fraction (QS/QT), cardiac output, physiologic dead space (VD/VT), and pulmonary vascular resistance were also measured. Light and electron microscopic histology confirmed early pathologic changes of oxygen toxicity in every animal after exposure. PaO2 in room air decreased markedly after exposure from 90 +/- 4 to 46 +/- 5 mm Hg, and QS/QT rose to 30 +/- 2%. VD/VT, PaCO2, and pH were not altered by exposure to hyperoxia. Similarly, cardiac output and pulmonary vascular resistance remained unchanged. The distribution of regional ventilation and perfusion remained normal during and after prolonged high-oxygen exposure. Early oxygen toxicity was characterized by profound hypoxemia without regional ventilation-perfusion mismatch. Although impaired diffusion through a thickened alveolar membrane may be partially responsible for this hypoxemia, the markedly increased alveolar-arterial oxygen gradient when FIO2 = 1.0 indicates that shunting at the alveolar level (secondary to absorptive collapse or pulmonary edema) is a major cause of the hypoxemia.

Animals↗
PubMed1980

Absorption, excretion and tissue distribution of stable zinc and 65zinc in ponies.

Absorption excretion and tissue distribution of stable Zn and 65Zn in mature ponies were studied in three experiments. In the first experiment, the metabolism of stable, dietary Zn and intravenously administered 65Zn was studied in three ponies in a 3 X 3 Latin square design. The ponies were fed a corn and beet pulp diet containing 35 mg Zn/kg or the same diet with 250 or 520 mg of supplemental Zn as ZnO. The ponies absorbed and retained more stable Zn when fed 250 mg of supplemental Zn that when fed the basal diet alone or the basal diet plus 520 mg of supplemental Zn. The ponies retained more 65Zn (percentage of dose) when fed the basal diet or the same diet with 250 mg of supplemental Zn. The intestinal tract was the major route of excretion of stable Zn and 65Zn. In the second experiment, the retention of an oral dose of 65Zn was studied in three ponies in a 3 X 3 Latin square design. The ponies were fed a beet pulp, corn starch and alfalfa meal diet containing 15 mg Zn/kg or the same diet with 240 or 480 mg of supplemental Zn as ZnO. The ponies retained a greater percentage of a dose of 65Zn when fed the basal diet or the basal diet plus 240 mg of supplemental Zn than when fed 480 mg of supplemental Zn. In the third experiment, four ponies fed a commercial pelleted diet containing 125 mg Zn/kg were given an intravenous dose of 65Zn. The ponies were killed 7 to 14 days after receiving the dose and tissues were counted for radioactivity. Parenchymatous organs such as liver, pancreas, kidney, heart and lung contained a greater percentage of 65Zn than did structural organs such as bone and muscle. The wall of the gastrointestinal tract contained more radioactivity than did the contents.

Animals↗
PubMed1980

Pulmonary tuberculosis in children.

A major change has occurred in the incidence and management of pulmonary tuberculosis in patients of all ages. This review emphasizes the effectiveness of drug therapy and the declining role of surgical management of pulmonary tuberculosis in children. Surgical intervention was necessary in only two of 140 children (1.4%) with proved tuberculosis, one for a large tuberculoma and the other for refractory involvement of the chest wall. The remaining 138 children were treated successfully with anti-tuberculous drugs. Pulmonary tuberculosis in children is primarily a medical disease and only rarely is surgical intervention indicated.

Adolescent↗
PubMed1980

Induced juglone toxicosis in ponies and horses.

Juglone, a toxic compound found in all parts of plants of the walnut tree family Jugans, was evaluated as the possible toxin involved in black walnut shaving-associated laminitis in the horse. Large amounts (up to 1 g) of this chemical administered per os inconsistently caused mild signs of laminitis in ponies. Topical application of juglone to the digits of horses caused local skin irritation but did not cause laminitis. Intravenous administration of juglone caused acute pulmonary edema in some individuals previously exposed to the compound per os or IV.

Animals↗
PubMed1980

Equine pelvic flexure impaction. A model used to evaluate motor events and compare drug response.

Pelvic flexure fistulas (2.5 cm diameter) were established in eight 160 kg Shetland X ponies. Impaction was induced at the pelvic flexure 25 times in the 8 animals through partial obstruction by a 1 litre rubber rebreathing bag fixed at the fistula site. Blood flow probes were implanted on the dorsal and ventral colic arteries (right colic artery and colic branch of ileocolic artery) in two of the ponies. Intraluminal pressure changes were measured at 8 different locations in the large colon during episodes of colic and following administration of flunixin or xylazine. Episodes of colic characterized by pawing, anxiety, anorexia, and attempts to lie down during impaction correlated with longer, louder sounds on auscultation and multiple contraction (closely grouped series lasting 3-5 minutes) of greater than 40 mm Hg as interpreted from simultaneous intraluminal pressure recordings. Flunixin and xylazine relieved clinical signs for 30-60 minutes. Xylazine resulted in cessation of intraluminal pressure changes for 30 minutes, Flunixin relieved signs but did not interfere with intraluminal pressure changes. Mean arterial blood flow through the colic arteries doubled during episodes of colic. Following administration of flunixin during colic, blood flow remained elevated; however, following administration of xylazine during colic, blood flow decreased.

Animals↗
PubMed1979

Corrosive injury to the stomach: the natural history and role of fiberoptic endoscopy.

Most physicians recognize that the ingestion of lye is associated with severe esophageal damage. It is much less widely known that gastric injury is the predominant finding when acid is ingested. We are reporting on five patients who had severe gastric damage after ingestion of diluted sulfuric acid (three cases), capsules of potassium hydroxide, and Clinitest tablets (one case each). Fiberoptic endoscopy was used to localize the extent and severity of injury and to follow the evolution of the damage. The extent and location of injury varied with the amount and type of agent ingested. Acid ingestion resulted in severe gastritis, which eventually led to antral stenosis and gastric outlet obstruction requiring operative intervention in two cases. Potassium hydroxide capsules produced diffuse esophagitis, gastritis, and a non-healing large gastric ulcer. Clinitest tablets produced distal esophagitis and stricture and antral damage leading to gastric outlet obstruction which required operative intervention. These cases demonstrate the natural history of corrosive injury to the stomach and the value of fiberoptic endoscopy in the management of this problem.

Acids↗
PubMed1979

Motor events in equine large colon.

The equine large colon is the major cellulose-fermentation locus of these species. The area of juncture of the ventral and dorsal divisions of the equine large colon was characterized, in 13 chronic unanesthetized animals and in 25 in vitro preparations, as an area of resistance to aboral flow. This is a probable pacemaker area. The reservoir function of this part of the colon is apparently facilitated by the presence of a pacemaker at this level. There was a general rise in recorded intraluminal pressure peaks during the first hour of feeding. This characteristic was not altered after resection of the extrinsic nerve supply. Electrical stimulation of the extrinsic nerve net in conscious animals at times mimicked the groups of intraluminal pressure peaks seen at the beginning of feeding.

Action Potentials↗