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Biomedical subjects

J McLaughlin

Publications and source records attributed to J McLaughlin.

At least 163 records · Page 9Linked to original sources
PubMed1979

Lipid composition of erythrocytes. Findings in Duchenne's muscular dystrophy and myotonic atrophy.

The distribution of major erythrocyte phospholipids and fatty aldehydes and the total fatty acid composition of erythrocytes and plasma were compared from patients with Duchenne's muscular dystrophy, from definite carriers of the disease, from patients with myotonic atrophy, and from a number of normal controls. The data for normal controls closely agreed with the accepted values for these lipid components. Contrary to the published reports of others, no abnormalities in lipids were found in either disease or carrier groups.

Adolescent↗
PubMed1978

Cholera, non-vibrio cholera, and stomach acid.

Fasting and postprandial stomach acid production were low in 16 of 37 Bangalees convalescing from cholera or non-vibrio cholera. Gastric juice of hypochlorhydric patients did not kill cholera vibrios in vitro, whereas that from normochlorhydric patients rapidly killed vibrios in concentrations up to 10(10)/ml. To determine whether hypoacidity resulted from cholera or was a common predisposing factor, basal and betazole-hydrochloride-stimulated acid production were measured before and after cholera in a second group of patients consisting of American volunteers participating in a vaccine development programme. Cholera did not alter the stomach acid secretion of American volunteers, but low precholera basal acid production predispose to severe cholera. The results indicate that hypochlorhydria observed in convalescent Bangalee cholera patients is not caused by cholera, and must therefore have preceded it. Idiopathic tropical hypochlorhydria may be a major factor accounting for the high incidence of diarrhoea due to acid-sensitive pathogens in developing countries.

Achlorhydria↗
PubMed1978

The presence of liver auto-antibodies induced by Entamoeba histolytica in the sera from both naturally infected humans and immunized rabbits.

Auto-antibodies against normal human liver have been detected in the sera of humans with highly positive indirect hemagglutination (IHA) amebiasis titers and with clinically-proven amebic liver abscess. Sera of amebiasis patients and rabbits immunized with killed Entamoeba histolytica were tested for anti-amebic antibodies by the IHA test and for auto-antibodies by the complement fixation test, using the antigens prepared from extracts of human liver and rabbit liver. A direct correlation was found to exist between high anti-Entamoeba antibody titers and the presence of anti-liver antibody in the serum. It is proposed that, in addition to direct parasite damage to host tissue, immunological damage could result from the attachment of circulating antigen to the cell surfaces of host tissues such as the liver.

Adolescent↗
PubMed1978

Membrane bound pyrophosphatases in Entamoeba histolytica.

Entamoeba histolytica homogenates are capable of hydrolyzing a range of inorganic and organic pyrophosphates. Two separate activities are present: an inorganic pyrophosphatase hydrolyzing inorganic pyrophosphate and linear tripolyphosphate, and a nucleoside diphosphatase hydrolyzing thiamine pyrophosphate and nucleoside diphosphates (ADP, GDP and UDP). The inorganic pyrophosphatase has an acid pH optimum, a relatively high KM (congurent to 1 micrometer) and is markedly heat stable and lacks a metal requirement. The nucleoside diphosphatase also has an acid pH optimum but displays a much higher affinity for substrate (KM congurent to 50 micrometer), is unstable to heating and is activated by Ca ions. Both pyrophosphatases distinct from the acid phosphatase activity which is also present. All three hydrolases are sedimentable and latent suggesting their association with membrane bounded organelles. No soluble inorganic pyrophosphatase activity could be demonstrated.

Animals↗
PubMed1977

Partial purification and some properties of a neutral sulfhydryl and an acid proteinase from Entamoeba histolytica.

The partial purification of two intracellular proteinases from the protozoan parasite Entamoeba histolytica is reported. One of these enzymes is an acid proteinase exhibiting maximum activity at pH 3.5 (hemoglobin substrate), is little affected by a range of inhibitors or activators, and is presumed to be similar to cathepsin D. Also present is a neutral proteinase exhibiting optimum activity at pH 6.0 (azocasein) but only poorly hydrolyzing either hemoglobin or serum albumen. This latter enzyme displayed no metal ion requirement, but was markedly inhibited by thiol-blocking agents and activated by free sulhydryl-containing compounds.

Animals↗
PubMed1977

The effect of electrical stimulation on the experimentally denervated rat muscle.

The m. quadriceps of white rats was electrically stimulated after nerve crush and after nerve section. Electrically stimulated muscles showed fewer central nuclei and a greater number of necrotic single fibres. The demonstration of motor endplates could not give a reliable indication of the onset of reinnervation. The various results show the importance of the trophic influence of the nerve and raise the suspicion that electrical stimulation has a retarding effect on the atrophy but also on regeneration of the fibres. After 7 weeks the unstimulated muscles show a greater degree of regeneration than the stimulated ones.

Animals↗
PubMed1976

Erythrocyte surface membrane alterations.

Electrophoretic mobility measurements were made of red blood cells obtained from patients with Duchenne and myotonic muscular dystrophy, from dystrophic mice and chickens, and from corresponding controls. Alterations in the erythrocyte surface electrokinetic properties were found in dystrophic mice and chickens and in many, but not all, patients with muscular dystrophy. The results are consistent with the concept of muscular dystrophy as a systemic membrane disease not limited to muscle.

Adolescent↗
PubMed1976

The subcellular distribution and properties of Crithidia sp. hydrolases with particular reference to pyrophosphate and orthophosphate monoester phosphohydrolases.

A cell fractionation scheme was developed for studying the distribution of certain hydrolases, especially phosphohydrolases in a Crithidia sp. (Trypanosomatidae). Whilst between 26-56% of the total cellular hydrolase activities were soluble (probably of flagellar pocket origin), a certain percentage, 5-40%, was sedimentable. A particulate fraction obtained after isopycnic density gradient centrifugation (p = 1.187-1.241), designated fraction FA/FB, was enriched in various acid hydrolases (relative specific activities 1.33-6.24) and displayed latent phosphohydrolase activities. The density gradient distributions of this hydrolytic enzymes were compared with reference to one another and malate dehydrogenase (mitochondrial marker). From the results obtained it appears that the sedimentable acid hydrolases of Crithidia are associated with a heterogeneous population of subcellular particles. Cytochemical observations on the FA/FB fraction supported this finding and revealed the association of acid phosphatase reaction product with subcellular elements resembling multivesicular bodies.

Animals↗
PubMed1976

Traumatic rupture of the aorta. A five-year experience.

In the five-year period ending in October, 1975, 31 consecutive patients with traumatic rupture of the thoracic aorta underwent surgery at the University of Maryland Hospital or the Maryland Institute for Emergency Medicine. All cases were confirmed by preoperative aortogram. Rupture was confined to one or more sites in the descending thoracic aorta at or distal to the origin of the left subclavian artery. The age was a mean of 26 years. Operation was done within an average of 18 hours after injury. Significant nonthoracic injuries were present in every case. Six patients with positive findings on peritoneal lavage underwent exploratory laparotomy prior to thoracotomy because of shock. Surgical repair was done by use of left heart bypass in 2 cases (one death), a passive aorta-aorta shunt in 23 cases (5 deaths), and without shunt or bypass in 6 cases (no deaths). An end-to-end tubular Dacron graft was used to reconstruct the aorta in all but one patient. Over-all survival rate was 25 of 31 patients (81 per cent). Paraplegia developed in one patient and renal failure in 3 patients (2 deaths) in the aorta-aorta shunt group. Hypertension was present in 18 (72 per cent) of the survivors. Palsy of the left recurrent laryngeal nerve persisted in 8 (32 per cent) of the survivors. Two of the deaths were related to technical problems of the shunting procedure and 2 to intrapleural exsanguination before proximal aortic control could be achieved. Complications and blood loss were reduced in the group with no shunt. The series lends support to the rigorous aortographic search for ruptured thoracic aortas in trauma patients with widened mediastinum. Once experience has been gained with shunting techniques, tears of the descending thoracic aorta may be safely repaired without shunt if done expeditiously.

Acute Disease↗