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Biomedical subjects

J Pepper

Publications and source records attributed to J Pepper.

At least 55 records · Page 3Linked to original sources
PubMed1992

Aortic dissection.

Aortic dissection, once thought to be rare, is the most common catastrophe of the aorta, being twice as common as ruptured abdominal aortic aneurysm. In one Inner London borough, aortic dissection accounted for 4.2% of sudden deaths in men over a three-year period. Early diagnosis and prompt treatment are crucial to achieving a successful outcome, because the events that influence survival occur early in the course of the disease. Surgical repair of aortic dissection is an uncommon operation in the United Kingdom. The Cardiac Surgical Register for 1988 (the most recent year available for analysis) reveals that 208 operations were performed to replace the ascending aorta, 12 operations to replace the aortic arch and 15 operations on the descending aorta during that year.

Aged↗
PubMed1991

Surgical treatment of coronary artery anomalies.

In this paper, we review literature from June 1990 through May 1991. We discuss normal anatomy and physiology of the proximal coronary arteries, anomalous origin of the coronary arteries from an inappropriate aortic sinus, and anomalous origin of the left coronary artery from the pulmonary artery. Other topics reviewed include coronary arteriovenous fistulas, coronary anomalies in left-sided heart syndrome and pulmonary atresia with intact interventricular septum, coronary arterial abnormalities in transposition of the great arteries, and iatrogenic coronary anomalies.

Arteriovenous Fistula↗
PubMed1990

Improved heart and lung preservation in a rat model.

We investigated the efficacy of four different preservation solutions in a heart-lung model in the rat. The heart and lungs of the donor were perfused under standardised conditions of temperature, pressure and flow. We studied 4 groups: group 1 received Stanford solution to heart and lung; group 2 received St. Thomas' solution to heart and Papworth solution to lung; group 3 received University of Wisconsin solution to heart and lung; and group 4 received University of Wisconsin solution to heart and Papworth solution to lung. Lung function assessed by arterial pO2 at a standardised FIO2 was significantly better in groups 2 and 4 than in other groups. However, cardiac function as assessed by cardiac output, stroke work index and minute work index was significantly better in group 4 than in any other group. Overall, the combination of solutions in group 4 provided the most effective preservation in this model.

Adenosine↗
PubMed1989

99Tcm-labelled meso-HMPAO and glutathione content of human lung tumours.

Levels of reduced glutathione (GSH) are increased in some types of malignant tumours and are known to influence the response to radio- and chemotherapy. In vitro studies suggest a correlation between cellular GSH concentration and retention of the meso form of hexamethyl propyleneamineoxime (HMPAO). This study investigates the relationship between in vivo tissue retention of 99Tcm-labelled HMPAO and GSH concentration in ten patients referred for thoracotomy for possible lung cancer. Retention of 99Tcm-HMPAO was measured using single photon emission computed tomography (SPECT). The tumour and normal lung concentration of reduced glutathione (GSH) was measured in tissue specimens collected peroperatively. Malignancy was confirmed in eight patients. Of seven patients undergoing curative resection for carcinoma, tumour GSH concentration was higher (mean 2.76 mM) than normal lung (mean 1.04 mM). In one neurofibroma, the GSH concentration was 1.80 mM. No correlation was found between 99Tcm meso-HMPAO retention and either the tumour GSH concentration or the tumour:lung GSH ratio. The results from this small series demonstrate that the intracellular GSH concentration of malignant lung tumours is generally higher than that in normal lung but that meso-HMPAO retention could not be used to predict these levels.

Carcinoma, Non-Small-Cell Lung↗
PubMed1988

Morphology of the endothelium over atherosclerotic plaques in human coronary arteries.

The right coronary arteries of six hearts removed from patients with atherosclerosis, who were undergoing cardiac transplantation, were perfused with 2% buffered glutaraldehyde for 20 minutes before preparation for scanning electron microscopy. Perfusion was started within five minutes of explanation. In two patients the artery was angiographically normal, in one it was irregular in outline, and three had focal segments with significant stenosis. None of the patients had concentrations of plasma lipids above 5.5 mmol/l. The endothelial surface showed widespread focal abnormalities ranging from adhesion and migration of monocytes to loss of individual endothelial cells. Larger areas of endothelial denudation with exposure of underlying collagen were also seen consistently. Loss of endothelial cells was associated with accumulation of monocytes, on and deep to the surface, as well as adhesion of platelets to the exposed subendothelial tissue. These results accord with the endothelial damage and platelet adhesion seen in hyperlipidaemic animals fed a high lipid diet.

Blood Platelets↗
PubMed1988

Changing controversies in surgery for angina.

Coronary artery surgery has evolved rapidly since its introduction 20 years ago. Few operations have been subjected to such scrutiny. As a result many details of prognosis have been clarified, but the development of coronary angioplasty, thrombolysis and the internal mammary artery graft have created new controversies.

Angina Pectoris↗
PubMed1986

Immunoreactivity in Limulus. II. Studies of serotoninlike immunoreactivity, endogenous serotonin, and serotonin synthesis in the brain and lateral eye.

Serotoninlike immunoreactivity was examined by the fluorescein-isothiocyanate-labeled secondary antibody technique in the lateral eye and brain of Limulus. Endogenous serotonin was measured with high-performance liquid chromatography and electrochemical detection. The synthesis of [3H]serotonin from [3H]tryptophan was measured in the presence and absence of reserpine. Fibers with serotoninlike immunoreactivity were found in the proximal stalks of the corpora pedunculata, in the neuropil of the central body, in the neuropils of the visual centers (lamina, medulla, and ocellar ganglion), in the optic tract that connects the ocellar ganglion with the posterior medial medulla, and in the central neuropil of the brain. Immunoreactive somata were found in four groups in the brain. Up to 50 somata were scattered through each side of the dorsal medial group that lies centered on the dorsal surface within the curve of the central body. These neurons innervate the central body neuropil and send processes into the central neuropil. Three or four reactive somata formed the ventral pole of each medullar group. These may provide the innervation of the proximal stalk of the corpora pedunculata. Five to ten reactive neurons were observed anteriorly in the ventral posterior lateral group #2 on each side that send processes into the central neuropil. Ten to 15 reactive somata were found on either side of the midline in the dorsal anterior part of the ventral medial group that contribute processes to the central neuropil. The remainder of the brain was not immunoreactive. No immunoreactive fibers or somata were found in the lateral eye or in the lateral optic nerve. Serotoninlike and substance P-like immunoreactivities were not found to be colocalized anywhere in the brain. Significant amounts of endogenous serotonin were detected in the lamina and medulla whose neuropils are rich in immunoreactive fibers and in the central body and dorsal medial group that are also rich in immunoreactive somata and fibers. No endogenous serotonin was detected in either the lateral eye or the lateral optic nerve. The lamina, medulla, and central body and dorsal medial group also synthesized and stored [3H]serotonin from [3H]tryptophan. It is likely that serotonin is a neurotransmitter in the brain, but not in the lateral eye of the horseshoe crab. In particular, it appears that serotoninergic neurons may play a role in central visual processing.

Animals↗
PubMed1985

Randomised placebo controlled trial of aspirin and dipyridamole in the prevention of coronary vein graft occlusion.

Treatment with the combination of aspirin and dipyridamole is believed to reduce the incidence of coronary vein graft occlusion. A double blind randomised controlled trial was carried out in which aspirin 990 mg and dipyridamole 225 mg daily or placebo were added to the routine postoperative management (warfarin for three months) of 320 patients undergoing coronary bypass grafting. The trial treatment was given for 12 months, after which the results were assessed by coronary and graft angiography. The two randomised groups, each of 160 patients, were comparable in age, sex, symptomatic state, angiographic findings, and operative procedure. Repeat coronary arteriography was carried out on 266 patients, 133 in each group. All grafts and distal anastomoses were patent in 68% (91/133) of the placebo patients and in 75% (100/133) of those receiving active treatment. Overall graft patency was 87% (306/352) and 89% (342/385) respectively. Retrospective subgroup analysis showed patency rates of 72% (26/36) and 78% (39/50) of grafts to vessels requiring preliminary endarterectomy, and 80% (36/45) and 91% (40/44) of distal anastomoses to vessels measured at operation to have a diameter of less than or equal to 1 mm. None of these differences was significant at the 5% level. Thus in this group of patients with high graft patency rates, treatment with aspirin and dipyridamole conferred no appreciable advantage.

Adult↗
PubMed1985

Origin and immunological hyporeactivity of canine alveolar lymphocytes.

Autochthonous canine thoracic duct lymphocytes were isolated, labelled with 111indium and injected intravenously. Direct sampling showed that the label passed from blood to lymph within 25 hr. By gamma camera imaging, the initial accumulation of 111In the liver and spleen was followed by a striking increase in lymph node associated activity between 24-36 hr. Although initial lung-associated counts were low, a bicarbonate-induced non-specific inflammation of the right lung induced a rapid and selective accumulation of labelled lymphocytes (ratio right to left lung 8:1). Cell suspensions lavaged from the alveolar surface showed only a 9% response to phytohaemagglutinin (PHA) compared to peripheral blood lymphocytes (PBL). The addition of unfractionated lavage cells to PBL caused a macrophage-dependent suppression of mitogen responsiveness. However, macrophage depletion of alveolar lavage cells did not restore the lymphocyte response to PHA. Similarly, the frequency of alloreactive precursors of cytolytic lymphocytes (CTL) was almost 10-fold less in alveolar lymphocytes compared to PBL. Thus, bronchoalveolar lavage provides a technique by which viable cells may be recovered in significant numbers from the alveoli and should be invaluable for the investigation of lung allograft rejection.

Animals↗
PubMed1975

Maternal serum FDP and circulating fetal red cells throughout pregnancy. A longitudinal study.

The presence of fetal red cells in the maternal circulation and the serum FDP content of 73 women was followed serially throughout a normal pregnancy. There was a signigicant increase in the mean serum FDP levels in late pregnancy, which was due to episodic elevations occurring in approximately 65% of women. These transient elevations appeared to increase in frequency and severity as pregnancy progressed. There was also an increase in the number of occasions fetal red cells were detected in the maternal circulation in the later months of pregnancy, but his phenomenon did not appear to be associated in any way to the serum FDP elevations. It is concluded that the episodic rises in serum FDP occurring in normal pregnancy are not related to episodes of occult disseminated intravascular coagulation secondary to placental haemorrhage as was previously hypothesized. Their etiology and clinical significance remain unknown.

Adolescent↗