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Biomedical subjects

J McDermott

Publications and source records attributed to J McDermott.

At least 73 records · Page 4Linked to original sources
PubMed1989

Expression of the three myeloid cell-associated immunoglobulin G Fc receptors defined by murine monoclonal antibodies on normal bone marrow and acute leukemia cells.

Monoclonal antibodies (MoAbs) have been prepared recently that recognize the three cell-surface receptors for the Fc portion of immunoglobulin (Ig), termed Fc gamma RI (MoAb 32.2), Fc gamma R II (MoAb IV-3), and Fc gamma R III (MoAb 3G8) that are expressed on selected subsets of non-T lymphocyte peripheral blood leukocytes. In the blood, Fc gamma R I is expressed exclusively on monocytes and macrophages, Fc gamma R II on granulocytes, mononuclear phagocytes, platelets, and B cells, and Fc gamma R III on granulocytes and natural killer (NK) cells. We have examined the expression of these molecules on normal bone marrow (BM) cells and on leukemia cells from the blood and/or BM in order to determine their normal ontogeny as well as their distribution on leukemic cells. BM was obtained from six normal volunteers and from 170 patients with newly diagnosed acute leukemia. Normal BM cells were found to express Fc gamma R I, II, and III with the following percentages: 40%, 58%, and 56%, respectively. Cell sorting revealed that both Fc gamma R I and Fc gamma R II were detectable on all subclasses of myeloid precursors as early as myeloblasts. Cell sorting experiments revealed that 66% of the granulocyte-monocyte colony-forming cells (CFU-GM) and 50% of erythroid burst-forming units (BFU-E) were Fc gamma R II positive with only 20% and 28%, respectively, of CFU-GM and BFU-E were Fc gamma R I positive. Acute myeloid leukemia (AML) cells expressed the three receptors with the following frequency (n = 146): Fc gamma R I, 58%; Fc gamma R II, 67%; and Fc gamma R III, 26% of patients. Despite the fact that Fc gamma R I is only expressed on monocytes among blood cells, AML cells without monocytoid differentiation (French-American-British [FAB]M1, M2, M3, M6) were sometimes positive for this receptor. However, Fc gamma R I was highly correlated with FAB M4 and M5 morphology (P less than .001). Fc gamma R II was also correlated with FAB M4 and M5 morphology (P = .003). Cells from 11 patients with acute lymphoblastic leukemia were negative for Fc gamma R I, but six cases were positive for Fc gamma R II and III (not the same patients). These studies demonstrate that Ig Fc gamma R are acquired during normal differentiation in the BM at or before the level of colony-forming units. In addition, we show that acute leukemia cells commonly express Fc gamma R.

Acute Disease↗
PubMed1989

The excretion of 5-oxoproline in urine, as an index of glycine status, during normal pregnancy.

The urinary excretion of 5-oxoproline, which may be used as an index of glycine status, was investigated in 30 normal pregnant women during different stages of pregnancy and in 18 non-pregnant female volunteers. During an 18-h study there was little variation in the 5-oxoproline/creatinine index, and a single sample gave a representative value. The excretion of 5-oxoproline/creatinine (mumol/mmol) rose progressively as pregnancy advanced (non-pregnant mean 10, SD 5, first trimester mean 46, SD 12, second trimester mean 150, SD 180, and third trimester mean 280, SD 320) and by the third trimester was over 20 times greater than in non-pregnant women. The data suggest that as pregnancy advances the endogenous production of glycine may be insufficient to satisfy the increasing demands.

Female↗
PubMed1986

[Percutaneous aspiration thromboembolectomy: an additional transluminal angioplasty method].

Percutaneous aspiration-thromboembolectomy is a simple method for removal of thrombo-embolic material of diverse origin. It is highly effective with small material outlay. As a third angioplasty method it has considerably improved the success rates of balloon dilatation and local lysis treatment with urokinase or streptokinase. The procedure was used alone or in combination on 71 occasions involving 69 limbs in 66 patients. An angiographically demonstrable success was seen in 96% and clinical improvement in 91.6%. Local lysis treatment with streptokinase or urokinase was shortened, less hazardous and, because of removal of non-lysable material, more successful. Embolectomy with the Fogarty catheter remains the method of choice for treating emboli arising from the heart in vessels of the aorto-iliac system. For smaller vessels below the inguinal ligament, however, we consider the new, lesser invasive method to be an alternative to vessel surgery.

Adult↗
PubMed1986

Myoclonus and parkinsonism.

We have observed three patients in whom the onset of parkinsonian signs was clinically associated with myoclonic movements. In each case, the parkinsonian signs were relatively mild and myoclonus was the major abnormality. The presentation of these three unusual cases within 1 year may be coincidental or may reflect a common pathogenetic mechanism. Adrenocorticotropic hormone was given to all three patients. It ameliorated the myoclonus in two patients but had no effect on the third.

Adrenocorticotropic Hormone↗
PubMed1985

Assay of protein kinase C with an N-bromosuccinimide-cleavage fragment of histone H1.

N-Bromosuccinimide cleavage of a lysine-rich histone fraction (histone III-S) yields a peptide substrate, purified by reverse-phase h.p.l.c., for the Ca2+ + phospholipid-dependent protein kinase (protein kinase C). This substrate displays no reactivity with the cyclic AMP-dependent protein kinase, and may prove useful for the detection of protein kinase C activity in crude tissue extracts.

Adipose Tissue↗
PubMed1985

[Conservative treatment of esophageal stenoses with balloon catheters].

A total of 92 dilatations using the balloon-catheter were carried out in 46 patients with oesophageal strictures. Of these 73 were in 36 patients having a benign primary disease, predominantly stenoses following anastomotic operations or with stenoses resulting from reflux oesophagitis. The average relapse-free period after balloon-catheter dilatation was 6.3 times greater than with bougienage. Balloon-catheter dilatation has proved to be a simple and safe procedure that can be applied inexpensively in an outpatient department. It has now become the method of choice in our hospital for the non-operative treatment of strictures of the oesophagus.

Deglutition Disorders↗
PubMed1979

Total hypothermic blood exchange in acute endotoxin shock.

It has been reported that total hypothermic blood exchange holds promise for the treatment of septic shock in animals. Since this procedure does not carry any mortality in out laboratory, we studied its effect in an acute septic shock model. After the intravenous injection of endotoxin (10 mg/kg) and blood transfusions into 33 dogs, severe haemoconcentration, tachypnoea, tachycardia, low cardiac output, metabolic acidosis and hyperpyrexia led uniformly to death within 5 h. All of these symptoms were prevented in five dogs by total hypothermic blood exchange, instituted 5 min after the endotoxin injection. Nevertheless, all of these treated animals died a delayed death. Since the endotoxin particles are rapidly phagocytosed by the reticulo-endothelial system, even very early total blood exchange cannot dislodge them from their intracellular site.

Animals↗
PubMed1979

Effect of hemodialysis on myocardial function as assessed by postural stress testing.

Myocardial performance, measured by systolic time intervals during passive postural stress, was evaluated in patients with end-stage renal disease before and after a single hemodialysis and compared with that of normal volunteers. Predialysis, the patients displayed a sluggish hemodynamic response to sudden postural changes. With tilting to 90 degrees, the patients' heart rate did not increase adequately and left ventricular ejection time (LVET) decreased only slightly in comparison to that of controls. Postdialysis, however, the response to sudden postural change in terms of increases in heart rate, decreases in LVET and decreases in calculated ejection fraction, were indistinguishable from those of control subjects. Since pre-ejection periods were not different from those of controls at any time during the test, we were unable to demonstrate a definite abnormality of myocaridal function before or after dialysis. The marked hemodynamic improvement in response to upright tilting, noted postdialysis, can be best attributed to a dialysis-related reduction in cardiac preload.

Adult↗
PubMed1978

Continuous electrode monitoring of systolic time intervals during exercise.

Current systolic time interval techniques have limited clinical applicability since patient co-operation and attention to the carotid pulse and phonocardiogram transducers are required. Therefore only surface electrodes were used to monitor the electrocardiogram and electrical impedance cardiogram first derivative (dZ/dt) in the acquisition of the timing signals. dZ/dt motion artefacts were eliminated by computerised ensemble averaging, thus permitting uninterrupted data acquisition. We studied the continuous response of multistage treadmill exercise on 13 normal volunteers, since maximal distortion of noninvasive measurements occurs in dynamic exercise. The individual response trends were combined for 6 symbolic indices and each mean index had a high statistical significance (P less than 0.001). This new method surveys continuously ventricular performance with surface electrodes and therefore has the potential of monitoring the ventricular performance of critically ill patients.

Adolescent↗
PubMed1975

Glutamate dehydrogenase specific activity and cephalosporin C synthesis in the M8650 series of Cephalosporium acremonium mutants.

Conditions for the accurate measure of glutamic dehydrogenase (GDH) from Cephalosporium acremonium were determined. K(m) values for alpha-ketoglutarate and ammonium ion were 7 and 15 mM, respectively. The half-saturation for reduced nicotinamide adenine dinucleotide phosphate was 5 muM. Reduced nicotinamide adenine dinucleotide did not serve as a cofactor for the enzyme. The specific activity of GDH was measured in six mutants of C. acremonium which varied in their ability to synthesize cephalosporin C. The mutants represented two separately derived lines, A and B. The four mutants in line B were characterized by a derepression of the GDH upon entry into stationary phase. The two mutants in line A were characterized by repressed levels of GDH during the same period. Both lines exhibited high GDH activity early in their fermentations, but activity decreased during the period of active cell growth. Cytochrome c concentrations followed the same pattern as total soluble intracellular protein. Line A mutants were low in cephalosporin C productivity and line B encompassed low, intermediate, and high productivity mutants. The relative frequency of yield improvements in line A and B indicate that the altered regulation pattern for GDH in line B may have removed a nitrogen limitation for cephalosporin C synthesis.

Acremonium↗