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Biomedical subjects

R D Gordon

Publications and source records attributed to R D Gordon.

At least 253 records · Page 14Linked to original sources
PubMed1985

Influence of selected patient variables and operative blood loss on six-month survival following liver transplantation.

A group of 118 adults who underwent primary, orthotopic transplantation of the liver over a 4-year period served as the subjects of a detailed examination of their ability to survive the first 6 months as a function of their preoperative condition. As a result, a scoring system was developed empirically in an attempt to separate very high-risk from relatively low-risk patients. The scoring method is based on the high degree of correlation between survival probability and various patient characteristics. It allows for additional scoring to account for the dramatic effect of operative blood loss on the eventual outcome. The curve that best describes the relationship between patient scores and survival probability is sigmoidal in shape. Many patients will have scores located on the curve between the inflection points. They represent a group whose relative risk is difficult to estimate but for whom operative blood loss or the occurrence of surgical complications may prove particularly telling.

Actuarial Analysis↗
PubMed1985

Retransplantation of the liver.

Since the introduction of cyclosporine-prednisone for primary immunosuppression, retransplantation has become a feasible option for patients whose primary grafts are failing, which may result from primary graft nonfunction, intractable rejection, or consequent to technical complications. Although survival of patients requiring second grafts is less good than in those whose initial graft functions well, 2-year survival rates of 49% have been achieved in retransplanted patients, a record that mandates serious consideration of this approach when the primary graft begins to fail. In general, the retransplant procedure is technically easier, with less blood loss, than is the initial operation. When the reoperation is done electively, it should be done before serious clinical deterioration compromises the chances for success.

Actuarial Analysis↗
PubMed1985

Role of liver transplantation in cancer therapy.

Fifty-four patients underwent total hepatectomy and liver replacement in the presence of a primary liver malignancy. In 13 recipients in whom the hepatic tumors were incidental to some other endstage liver disease, recurrence was not seen and 12 of the 13 patients are alive after 4 months to 15 1/2 years. In contrast, tumors recurred in 3 of every 4 patients who received liver replacement primarily because of hepatic malignancies that could not be resected by conventional techniques of subtotal hepatectomy and who lived for at least 2 months after transplantation. The most encouraging results were in patients with the fibrolamellar hepatocellular carcinomas that grow slowly and metastasize late, but even with this lesion, the recurrence rate was 57%. In future trials, additional effective anticancer therapy will be needed to improve the results of liver transplantation for primary liver malignancy, but what an improved strategy should be has not yet been defined.

Adult↗
PubMed1985

Clinical presentation of hepatic artery thrombosis after liver transplantation in the cyclosporine era.

Hepatic artery thrombosis is a dreadful complication of orthotopic liver transplantation. It should be suspected in cases of fulminant liver failure, delayed bile leak, or intermittent sepsis of unknown cause after liver transplantation. Accurate diagnosis is assisted by ultrasound and computerized tomography scans, but usually requires arteriography. Prompt retransplantation is required in most of the cases.

Adult↗
PubMed1984

A comparison of cardiovascular and catecholamine responses to three stimuli in mild hypertension.

In five males with mild essential hypertension, simultaneous hemodynamic and arterial and venous plasma catecholamine responses to three stimulation tests (mental arithmetic, isometric handgrip exercise, and cold) were studied. Plasma norepinephrine (NE), epinephrine (EPI), and dopamine (DA) were measured radioenzymatically. Isometric exercise was the best stimulus for systolic and diastolic blood pressure and NE. Mental arithmetic produced the highest levels of plasma EPI, but there was great intersubject variability. Dopamine levels did not increase with any of these stimuli. Consistent arterio-venous differences across the forearm were seen for EPI but not NE, consistent with local production of NE. Isometric exercise produced the closest correlations between peripheral plasma catecholamine levels, blood pressure, and heart rate. Good correlations were seen with mental arithmetic, but with the stimulus of cold correlation was poor.

Adult↗
PubMed1984

Basic information for microcomputer data base management.

Paper-based information systems are cumbersome and inefficient. The microcomputer is an attractive, affordable, and powerful alternative to traditional paper-based record keeping. This article reviews fundamentals of data base management and microcomputer technology for the surgeon interested in microcomputer-based information systems.

Computers↗
PubMed1984

Monoclonal antibodies against the voltage-sensitive Na+ channel from mammalian skeletal muscle.

A panel of 13 monoclonal antibodies against the voltage-sensitive Na+ channel of rat skeletal muscle has been characterized. Each of these antibodies reacted with the purified Na+ channel protein in a solid-phase radioimmunoassay. Nine antibodies specifically immunoprecipitated the Na+ channel in a form that retained its characteristic high affinity for saxitoxin, and 11 recognized the channel in a crude mixture of solubilized membrane proteins separated on a Sepharose CL-6B column. Six antibodies specifically labeled skeletal muscle in immunofluorescence techniques. In each case, antibody was localized only to the surface membrane of the muscle fibers. Eleven antibodies produced detectable reaction on immunoblot transfers of sarcolemmal membrane proteins; each of these bound to a diffuse 160- to 200-kDa band that comigrated with the large glycoprotein subunit of the purified Na+ channel. Further studies were carried out with one of these antibodies, L/D3. In immunoblots of a glycoprotein fraction prepared from muscle that had been homogenized rapidly in a solution containing detergent, EGTA, and protease inhibitors, L/D3 recognized only a single 260-kDa band. Incubation of solubilized muscle proteins at 4 degrees C for 24 hr without EGTA prior to isolation of the glycoprotein fraction resulted in partial conversion of this 260-kDa component to a smaller component between 160 and 200 kDa that comigrated with the principal immunoreactive component of sarcolemma. Based on its immunoreactivity with monoclonal antibodies, the large subunit of the rat skeletal muscle Na+ channel appears to be approximately equal to 260 kDa in its native state but may be sensitive to proteolysis during the isolation of sarcolemmal membranes.

Animals↗
PubMed1984

Increased plasma noradrenaline during adrenaline infusion in man.

Arterial and venous plasma noradrenaline in recumbent mild hypertensives, and in normotensives with one adrenal gland, increased significantly during infusion of adrenaline to achieve levels similar to those seen during mental arithmetic stress. Although decreased noradrenaline clearance has not been excluded as an explanation of increased plasma levels, these results are consistent with the hypothesis that physiological concentrations of adrenaline are capable of facilitating noradrenaline release in man.

Adrenalectomy↗
PubMed1983

Severe chronic mucocutaneous candidiasis. Favourable response to oral therapy with ketoconazole.

Severe, early-onset, chronic mucocutaneous candidiasis was associated with bronchiectasis, oesophageal stricture, short stature and delayed puberty in a male aged 18 years. Topical treatment with antifungal agents, and several courses of intravenously administered transfer factor, amphotericin, and miconazole achieved only minor or transient improvement in the patient's condition. Correction of iron deficiency anaemia did not lead to alleviation of candidiasis. Skin reactivity to Candida antigen was absent and T-lymphocytes, which responded normally to phytohaemagglutinin (PHA), poke-weed mitogen and concanavalin A, had negative macrophage-inhibiting factor (MIF) and blastogenic responses to Candida antigen. Treatment with the orally effective imidazole derivative, ketoconazole, produced improvement within three days and clearing of mucosal lesions within five weeks. The patient then entered puberty spontaneously at the age of 20 years. After 18 months of treatment with ketoconazole, without side effects, the clinical manifestations of mucocutaneous candidiasis have not recurred. Because of the possibility of continuous, long-term administration, ketoconazole represents the best currently available agent for the treatment of chronic mucocutaneous candidiasis.

Adolescent↗
PubMed1983

Effects of anoxia on the stimulated release of amino acid neurotransmitters in the cerebellum in vitro.

The effect of anoxia and ischemia on the release of amino acid transmitters from cerebellar slices induced by veratridine or high [K+] was studied. Synaptic specificity was tested by examining the tetradotoxin (TTX)-sensitive and the Ca2+-dependent components of stimulated release. Evoked release of endogenous amino acids was investigated in addition to more detailed studies on the stimulated efflux of preloaded [14C]GABA and D-[3H]aspartate (a metabolically more stable anologue of acidic amino acids). [14C]GABA release evoked by either method of stimulation was unaffected by periods of up to 35 min of anoxia and declined moderately by 45 min. In contrast, induced release of D-[3H]Asp increased markedly during anoxia to a peak at about 25 min, followed by a decline when anoxia was prolonged to 45 min. Evidence was obtained that the increased evoked efflux of D'[3H]Asp from anoxic slices was not due to impaired reuptake of the released amino acid and that it was completely reversible by reoxygenation of the slices. Results of experiments examining the evoked release of endogenous amino acids in anoxia were consistent with those obtained with the exogenous amino acids. Only 4 of the 10 endogenous amino acids studied exhibited TTX-sensitive veratridine-induced release under aerobic conditions (glutamate, aspartate, GABA, and glycine). Anoxia for 25 min did not affect the stimulated efflux of these amino acids with the exception of glutamate, which showed a significant increase. Compared with anoxia, effects of ischemia on synaptic function appeared to be more severe. Veratridine-evoked release of [14C]GABA was already depressed by 10 min and that of D-[3H[Asp showed a modest elevation only a 5 min. Stimulated release of D-Asp and labelled GABA declined progressively after 5 min. These findings were compared with changes in tissue ATP concentrations and histology. The latter studies indicated that in anoxia the earliest alterations are detectable in glia and that nerve terminals were the structures by far the most resistant to anoxic damage. The results thus indicated that evoked release of amino acid transmitters in the cerebellum is compromised only by prolonged anoxia in vitro. In addition, it would appear that the stimulated release of glutamate is selectively accentuated during anoxia. This effect may have a bearing on some hypoxic behavioral changes and, perhaps, also on the well-known selective vulnerability of certain neurons during hypoxia.

Amino Acids↗
PubMed1983

Factors affecting the frequency of occurrence of spironolactone bodies in aldosteronomas and non-tumorous cortex.

Histological sections taken from aldosterone-producing-adenomas and from non-tumorous adrenal cortex of 18 patients treated for primary aldosteronism by unilateral adrenalectomy were examined for spironolactone inclusion bodies. Typical inclusions were found in 10 of the 13 patients who received spironolactone up to within 24 h of surgery. They were present in the tumours of 7 patients, and their frequency correlated positively with the percentage of glomerulosa type cells in the tumours. In tumours containing 50% or more glomerulosa-type cells, their frequency correlated negatively with duration of treatment. They were present in the non-tumorous cortex of 4 of these 7 patients, and in the cortex of 3 others whose tumours did not contain them. In the cortex, they were found only in glomerulosa cells, and their presence appeared unrelated to dosage or duration of treatment. No spironolactone inclusion bodies were seen in either the tumour of the non-tumorous cortex of 3 patients who had discontinued spironolactone 19 to 97 d before surgery, or of 2 patients who had never received spironolactone.

Adenoma↗
PubMed1983

Different norepinephrine disappearance rate in venous and arterial plasma in man.

The disappearance of norepinephrine in both arterial (radial) and venous (antecubital) plasma was studied in five patients with mild essential hypertension following isometric exercise and norepinephrine infusion. Arterial levels of epinephrine throughout the study and of norepinephrine during norepinephrine infusion were consistently higher than venous levels, indicating that both amines are removed by passage through the forearm. Following infusion the disappearance rate of norepinephrine from arterial plasma was faster than from venous plasma. After isometric exercise there was a delay in fall of venous levels, consistent with a delayed efflux of norepinephrine from local tissues. Arterial plasma levels probably reflect total body contribution whereas venous plasma levels presumably reflect additional local removal and/or release from the forearm.

Adult↗
PubMed1982

Putative acidic amino acid transmitters in the cerebellum. I. Depolarization-induced release.

In the present investigation we studied the autoradiographic localization and the characteristics of the depolarization-induced release of acidic amino acids in in vitro rat cerebellar preparations. Light microscopy autoradiography of cerebellar slices preincubated in the presence of the non-metabolized glutamate analogue D-[3H]aspartate showed a large accumulation of radioactivity over glial cells, and very little labelling of the granule cells, whose putative neurotransmitter may be glutamate. In spite of its predominant localization in glia, D-[3H]aspartate (and [14C]glutamate) was released from cerebellar slices depolarized with high [K+] in a Ca2+-dependent way, and the release elicited by veratrine was prevented by TTX. These findings, together with the observation that freshly isolated or cultured glial cells did not show any Ca2+-dependent, depolarization-induced release of D-[3H]aspartate, suggest that the radioactive amino acid released from slices has a neuronal origin. The high [K+]-induced release of exogenous radioactive acidic amino acids from superfused cerebellar synaptosomal preparations exhibited, as best, a modest Ca2+-dependence, a result probably due to the existence of a substantial non-Ca2+-dependent release of the amino acid from glial fragments contaminating the preparation. However, both the K+-evoked release of endogenous glutamate, and that of [14C]glutamate previously synthesized from [14C]glutamine were largely Ca2+-dependent, suggesting that nerve endings are the main sites involved in the stimulus-coupled secretion. In the experiments in which synaptosomes had been prelabelled with [14C]glutamine, a study of the specific radioactivity of the glutamate released and of that present in synaptosomes at the beginning and at the end of superfusion period provided evidence in favour of a preferential release of the newly synthesized [14C]glutamate. In contrast to glutamate, endogenous aspartate was not released in a Ca2+-dependent manner, and the efflux of newly formed [14C]aspartate was only slightly potentiated by Ca2+, which suggests that glutamate and aspartate are not released from the same sites. Studies on preparations (slices and synaptosomes) from immature, 8-day-old cerebella showed that neither the K+-evoked release of D-[3H]aspartate, nor that of endogenous glutamate was Ca2+-dependent. In conclusion, the data presented are consistent with the proposition that glutamate has a neurotransmitter role in the cerebellum.U

Amino Acids↗