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Biomedical subjects

M S Murphy

Publications and source records attributed to M S Murphy.

At least 55 records · Page 3Linked to original sources
PubMed1989

Achalasia of the cardia associated with hereditary cerebellar ataxia.

Achalasia of the cardia, a disorder associated with degenerative loss of esophageal myenteric ganglion cells, is reported in association with a recently described progressive neurological disorder, "early onset cerebellar ataxia with retained reflexes." This form of cerebellar ataxia is thought to be inherited as an autosomal recessive disorder. The occurrence of these two very rare neurodegenerative disorders in a single individual is of interest because of the potential genetic and pathogenetic implications of the association.

Child↗
PubMed1988

Measurement of small intestinal transit time in children.

The lactulose hydrogen breath-test provides a non-invasive measure of mouth to caecum transit-time. Its use, particularly in children has not been thoroughly investigated. We have studied the effects on transit time of altering the lactulose concentration of the test solution, and of administering it in a liquid nutrient preparation. Concentration markedly affected transit-time; studies with an isotonic solution may be least affected by delayed gastric emptying, and so may reflect small bowel transit-time. Day-to-day variation was large, and was not reduced by altering lactulose concentration, or by using the liquid nutrient based test solution. There was no correlation between age and transit-time.

Adolescent↗
PubMed1988

Percutaneous cardiopulmonary bypass limits myocardial injury from ischemic fibrillation and reperfusion.

Percutaneous implementation of cardiopulmonary bypass (PCPB) with a synchronous pulsatile pump has been shown to be an efficient means of unloading the heart. Therefore, this technique may provide a practical and effective method for treating patients undergoing a major cardiac catastrophe who are unresponsive to the usual resuscitative efforts. We tested whether PCPB could effectively unload the heart and provide myocardial salvage during left anterior descending (LAD) coronary artery occlusion complicated by ventricular fibrillation in the canine model (n = 13). All 13 dogs fibrillated within 20 minutes of LAD occlusion, and none could be successfully resuscitated by manual cardiac compression, sodium bicarbonate administration, antiarrhythmic agent administration, and electrical defibrillation. All 13 dogs were then placed on PCPB by way of the right jugular vein and right femoral artery; in seven, we used a synchronous pulsatile pump and in six a standard roller pump. No vent was placed in the left ventricle. All animals returned to normal sinus rhythm within 20 minutes of institution of PCPB. The LAD snare was released after 2 hours, and all animals were maintained on PCPB during 3 hours of reperfusion. At sacrifice, the area of infarction was determined by staining with triphenyltetrazolium chloride and was expressed as a percentage of the left ventricular area-at-risk for infarction. The tension time index was also measured and expressed as percent change from baseline. The left ventricular area-at-risk for infarction was similar in both groups (31.5% for roller pump vs. 29.2% for pulsatile pump; p greater than 0.05), but the area of infarction as a percentage of the area at risk was significantly smaller in the pulsatile-pump group (22.0%) than in the roller-pump group (35.4%; p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Duodenal ulceration: review of 110 cases.

This paper describes 110 cases of childhood duodenal ulcer, which were diagnosed over 26 years: 63 were diagnosed by barium meal examination; 47 by upper gastrointestinal endoscopy. The mean age at diagnosis was 11.2 years, with symptoms reported in 46% before 10 years and in 15% before 6 years of age. There was often a considerable delay in diagnosis, particularly in the younger age group. Nocturnal pain (61%) and a close family history of duodenal ulcer disease (62%) were the most valuable pointers to the diagnosis. Fifteen children had required surgery for persistent symptoms. Thirty four had received treatment with an H2 receptor antagonist, and all but four had had a satisfactory initial response. Seventy per cent relapsed within six months of discontinuing treatment, and long term maintenance treatment may therefore be necessary.

Adolescent↗
PubMed1987

A comparison of methods for limiting myocardial infarct expansion during acute reperfusion--primary role of unloading.

Current use of angioplasty, thrombolysis, and surgical techniques for prompt reperfusion of an acute myocardial infarction raises questions concerning the optimum reperfusion technique for maximum myocardial salvage. Alterations in the conditions of reperfusion and/or the composition of the initial reperfusate can exert a significant effect on the extent of myocardial salvage. In an effort to define an optimum reperfusion technique, we used 40 dogs in a series of experiments in which the left anterior descending coronary artery (LAD) was snared for 2 hr followed by reperfusion by one of five methods for 4 hr. In addition, in a control group(group I, n = 6) the LAD was occluded for 6 hr without any reperfusion. In group 2 (n = 12), simulating medical reperfusion, reperfusion was achieved by simply releasing the snare for 4 hr. Group 3 dogs (n = 6) were placed on pulsatile left atrial-femoral bypass throughout 4 hr of reperfusion. Group 4 dogs (n = 9) were placed on percutaneous, synchronized pulsatile cardiopulmonary bypass during reperfusion. The procedure in group 5 (n = 7) dogs simulated coronary artery bypass grafting with cardiopulmonary bypass and cold blood, low-Ca++ cardioplegia during reperfusion. Group 6 (n = 6) was treated similarly except that during reperfusion amino acid-enriched cardioplegia was administered by warm induction techniques. At the end of 4 hr of reperfusion, the left ventricular area of infarction was determined by triphenyltetrazolium chloride staining and expressed as a percentage of the left ventricular area at risk for infarction (area of infarction [AI]/area at risk [AR]).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Percutaneous cardiopulmonary bypass with a synchronous pulsatile pump combines effective unloading with ease of application.

Percutaneous total cardiopulmonary bypass offers the advantage of rapid, simple implementation without the need for thoracic incision and provides the ability to support both left and right ventricular failure as well as pulmonary insufficiency. Previous studies using roller pump percutaneous bypass were only partially successful because of the inability to effectively unload the left ventricle. In the present experiment we attempted to determine in a normal canine model whether use of synchronous pulsatile pumping for percutaneous bypass could overcome this problem. Fourteen dogs were placed on percutaneous bypass for 1 hour. A roller pump was used in seven and a synchronous pulsatile pump with an electrocardiogram triggering mechanism in the other seven. All animals were maintained on percutaneous bypass for 1 hour. In the pulsatile pump group there was a significantly greater percent decrease from baseline in tension-time index (-56.3% versus -19.1%, p less than 0.01) and in myocardial oxygen consumption (-45.8% versus +2.1%, p less than 0.05) and a significantly greater percent increase in the endocardial/epicardial blood flow ratio (27.6% versus -6.5%, p less than 0.01) than in the roller pump group. These results show that superior unloading can be achieved by percutaneous pulsatile bypass compared with percutaneous roller pump bypass. The findings suggest that percutaneous total cardiopulmonary bypass with a synchronous pulsatile pump offers a relatively simple but effective method for providing appropriate patients with temporary hemodynamic stability before cardiac catheterization or medical or surgical revascularization.

Animals↗
PubMed1984

Modification of oral methotrexate absorption in children with leukemia.

The effect of administering oral methotrexate in different formulations to children with acute lymphoblastic leukemia was evaluated. Methotrexate tablets alone achieved higher mean plasma levels and larger area under the absorption curve than either methotrexate liquid alone or methotrexate tablets taken concurrently with metoclopramide.

Absorption↗
PubMed1978

The relationships among arterial oxygen flow rate, oxygen binding by hemoglobin, and oxygen utilization in chronic cardiac decompensation.

We have examined the interrelationships among CaO2, blood flow, oxygen binding by hemoglobin, and VO2 in cardiac patients with and without chronic cardiac decompensation. We have quantified the role that decreased oxygen-binding to hemoglobin may play in maintaining VO2 in the presence of low systemic blood flow rates. The volume rate of oxygen delivery to tissues was expressed as the OFIa, the product of CO2 and blood flow. OFIa varied from 738 to 262 ml/min/m2, whereas VO2 varied from 170 to 117 ml/min/m2. Thus, in the patients with lowest OFIa (63% below the highest OFIa), VO2 was only down 19%. VO2 was maintained because the extraction of oxygen rose from about 20% to 50% in close association with the decrease in OFIa. Oxygen binding to hemoglobin was lower in patients with the lowest OFIa--and therefore, at in vivo conditions of pH, PCO2, and temperature, P50 in vivo was higher. The resulting facilitation of oxygen release at the PO2 of tissue capillaries could explain about one third of the observed increment in oxygen extraction in patients with low OFIa. An alternative interpretation is that a high P50 in vivo minimizes the reduction in PVO2 needed to maintain VO2 when increased proportional extraction of O2 compensates for decreased OFIa.

Aged↗
PubMed1976

Detection of mutant hemoglobins with altered affinity for oxygen. A simplified technique.

The detection of high- or low-affinity hemoglobins in subjects with polycythemia or anemia is difficult for most physicians because of the requirement for special equipment to do oxygen-hemoglobin dissociation curves. Measurement of the pH, oxygen tension, and oxygen saturation of antecubital venous blood with instruments present in most clinical chemistry laboratories permits an estimate of the strength of oxygen binding to hemoglobin. An equation can be used to convert the venous oxygen tension (standardized to pH 7.4) and the oxygen saturation to the P50 of the oxygen-hemoglobin dissociation curve on which the observed point falls. The data indicate that this method is a reliable initial step in the identification of a hemoglobin with abnormal affinity for oxygen and may be applied to population studies, since reliable results are obtained with venous blood stored at 4 degrees C for up to 24 hours.

Hemoglobins, Abnormal↗
PubMed1975

Acidification of plasma by the red cell due to radiographic contrast materials.

The effect of water-soluble radiographic contrast material on pH when added to blood in clinical dosages in vitro or when used in vivo for diagnostic purposes was examined. Contrast material caused a reduction of blood pH. The mechanism of this occurence was found to be the balancing of the negative charge of intracellular organic anions by the extracellular anionic contrast material molecules. The normal negative potential of about 10 mV across the red cell membrane was reduced, nullified, or reversed depending on the concentration of contrast material added to blood. As the inside of the cell became more positive with respect to the outside, protons were, in effect, repelled into plasma, although the apparent exodus of protons occurs by the generation and outward diffusion of carbon dioxide. Since the acidemia is dependent on rehydration of carbon dioxide in plasma, a reaction measured in seconds, the site of injection and transit time of dye will contribute to the pH of the plasma during passage through a regional capillary bed. We speculate that an alteration in membrane potential and/or the acute acidemia may contribute to the adverse effects of contrast material, particularly on tissues dependent on membrane electrical rhythmicity such as the myocardium.

Acidosis↗
PubMedDate not supplied

Thyroid function in haemochromatosis.

BACKGROUND: In hereditary haemochromatosis (HH), the thyroid gland is the site of substantial iron deposition. However, there have been relatively few reported cases of thyroid dysfunction in HH. AIM: To evaluate the prevalence of thyroid disorders in a large group of patients with HH. METHODS: A variety of endocrine investigations were undertaken including thyroid function tests and thyroid antibody studies. RESULTS: A total of 154 consecutive patients (123 male, 31 female) were studied. One case of primary hypothyroidism was identified, giving a prevalence of 0.6%. Subclinical hypothyroidism was identified in two females, giving a prevalence of 1.3%. Iatrogenic hypothyroidism was identified in two other cases. No case of hyperthyroidism was identified. CONCLUSION: Thyroid dysfunction is an uncommon occurrence in patients with HH.

Adult↗
PubMedDate not supplied

Transient global amnesia after sexual intercourse.

BACKGROUND: Transient global amnesia presents as paroxysmal, transient loss of memory function and has been shown to have a number of inciting factors. AIMS: To report a case and its inciting factor in order to heighten awareness of the condition. METHODS: A 56-year-old woman who presented with TGA after sexual intercourse is reported. RESULTS: The episode of TGA resolved after 14 hours. Results of laboratory tests including MRI brain and MR angiogram and venogram were normal. CONCLUSION: An inciting event can often be identified for TGA and a targeted history should be used to help elicit such events.

Amnesia, Transient Global↗
PubMedDate not supplied

Reduced emergency department stabilization time before cranial computed tomography in patients undergoing air medical transport.

INTRODUCTION: Advanced patient stabilization skills provided by air medical providers were hypothesized to result in streamlined emergency department (ED) stabilization of patients with head injuries requiring urgent cranial computed tomography (CCT). The goal of this study was to compare initial ED stabilization times between air- and ground-transported patients requiring urgent CCT and emergency neurosurgical hematoma evacuation. SETTING: Academic Level trauma center (annual ED census 60,000) receiving patients from ground EMS and a nurse/paramedic air medical transport team. METHODS: This retrospective study identified, from a database of 15 months of ED visits, consecutive group of adults who had CCT performed within 60 minutes of ED arrival and underwent emergent craniotomy for intracranial hematoma. Demographics, hemodynamic status, patient acuity, and time intervals between ED and CCT suite arrivals were compared between air and ground patients using chi-square, Fisher's exact, and t-tests (p = 0.05). RESULTS: Eleven air- and 39 ground-transported patients were eligible. All patient acuity data were similar between groups. Air patients were more likely to be intubated (100% versus 71.8%, p = .04) and had shorter mean ED stabilization times (29 versus 40 minutes, p = .02) than the ground. CONCLUSION: This study suggests that advanced patient stabilization offered by air medical transport may result in reduced ED stabilization time for patients requiring urgent craniotomy.

Academic Medical Centers↗
PubMedDate not supplied

Reduced red cell membrane potential and acidification of the plasma in response to contrast materials. Time course of the alteration in plasma pH.

Radiographic contrast materials added to blood reduce the red cell membrane potential by balancing the internal impenetrable anions, hemoglobin and organic phosphates. In so doing, a redistribution of protons occurs such that plasma is acidified. The time course of acidification of plasma is measured in seconds, with a nadir of pH occurring 12 to 15 seconds after addition of Hypaque (1.5 to 3.0 ml/10 ml blood) and a half-time of acidification requiring about 6 seconds. The acidification process is slowed in part by an initial alkalosis due to Hypaque. The acidification of blood is more rapid after addition of Renografin (1.5 to 3.0 ml/10 ml blood) than after addition of Hypaque since the former solution is slightly acidic. The time course of plasma acidification indicates that a maximal reduction in blood pH may not occur in the capillaries of a regional circulation following injection of contrast materials into its afferent vessel, since the transit time of the contrast material may be less than the time required for maximal acidification of plasma.

Blood↗
PubMedDate not supplied

Peptic ulcer disease in childhood: long-term prognosis.

Information concerning the natural history of peptic ulcer disease commencing in childhood is limited. We have followed up 19 individuals in whom this diagnosis had been made in childhood 14-27 years previously. Strict diagnostic criteria were used. A high incidence of morbidity persisting into adult life was found. On investigation 9 (47%) had had a proven ulcer since entering adult life. Ten (53%) were no longer prone to recurring abdominal pain, but four of these had undergone vagotomy and pyloroplasty (three after the age of 21) for intractable symptoms. Thus, only six patients (31%) had made a lasting and spontaneous recovery. Serious complications had occurred at some time in the past in 10 cases (53%). Overt gastrointestinal bleeding had occurred in eight (42%), and this had been after the age of 18 years in three. Duodenal perforation occurred in one subject, and severe pyloric stenosis in another, both of whom were aged 21 years. One subject developed a penetrating duodenal ulcer at the age of 24 years. Seven (37%) had undergone surgery, and in two of these cases more than one operation had been performed. Fifty-eight percent of complications suffered and 89% of surgical operations performed involved patients of 21 years or older. These findings firmly reinforce the opinion that the disorder frequently persists into adult life. The impact of modern means of medical therapy, such as the H2 receptor antagonists, has not yet been fully evaluated.

Adolescent↗