Search PubMed⌕ Search

Biomedical subjects

A Hughes

Publications and source records attributed to A Hughes.

At least 199 records · Page 11Linked to original sources
PubMed1981

Heterogeneous blast cell crises in Philadelphia negative chronic granulocytic leukaemia.

A case of Philadelphia negative chronic granulocytic leukaemia (Ph1-CGL) is described showing features only previously demonstrated in Ph1+ disease. These features include: (1) lymphoid blast crisis, determined by morphology and immunological marker analysis; (2) dual blast cell populations that can be distinguished both morphologically and by immunological markers; (3) clonal evolution, as shown by the emergence of chromosome markers and in one of the cell lines a change in membrane phenotype. These changes were apparently associated with the emergence of a relatively drug resistant subclone of leukaemic cells. This study demonstrates that the lymphoid blast crisis of CGL, and its sequelae, can occur in Ph1- cases. It is similar in respect to morphology, enzyme, and membrane markers and responsiveness to vincristine and prednisolone therapy to the lymphoid blast crisis seen in Ph1+ CGL. This suggests that the Philadelphia chromosome is a clonal marker only, and its presence is not directly related to the subsequent clinical course of the disease.

Bone Marrow↗
PubMed1981

Buffy coat and cell separator granulocyte concentrates. Comparison of cell content and in vitro granulocyte function.

Buffy coat granulocyte concentrates were prepared manually from single fresh whole blood donations after centrifugation. The erythrocyte, granulocyte and platelet numbers in these concentrates were compared to cell numbers in concentrates obtained by mechanical leukapheresis using intermittent flow centrifugation. Buffy coats contained approximately half the number of granulocytes and three times the number of erythrocytes per unit volume than cell separator concentrates. There was no difference in platelet numbers. Thus to give a therapeutic dose of granulocytes equivalent to that obtained by cell separation, 2-3 times greater volume of buffy coat concentrates would be required. In vitro granulocyte function, as measured by migration, phagocytosis, and Candida killing was also compared in buffy coat and cell separator concentrates. The only difference found was reduced Candida killing in the buffy coat granulocytes. The possible clinical use of buffy coat concentrates, as a source of granulocytes, is discussed.

Blood Cell Count↗
PubMed1981

Repair of salt tolerance and recovery of lost D-alanine and magnesium following sublethal heating of Staphylococcus aureus are independent events.

Sublethal heating of Staphylococcus aureus S6 in potassium phosphate buffer caused loss of salt tolerance, D-alanine, and magnesium. During incubation in rich complex media all three of the damaged sites were repaired. Repair occurred more slowly but went to completion in a dilute synthetic medium (DSM), free of D-ala. DSM plus penicillin or D-cycloserine allowed repair of salt tolerance but recovery of normal levels of D-ala or Mg was prevented. When DSM-repaired cells were cultured into fresh rich medium they grew rapidly after a short lag. Cells which had acquired their salt tolerance in DSM plus cycloserine and were D-ala and Mg deficient grew slowly and had a lag of 3 h. We suggest that heat damage has two separate primary targets in S. aureus cells: the membrane, which is manifested by loss of salt tolerance, and a second site, possibly teichoic acids, manifested by loss of D-ala and Mg.

Alanine↗
PubMed1981

Salt extends the upper temperature limit for growth of food-poisoning bacteria.

Inclusion of NaCl into the growth medium raised the upper temperature limit of growth of the following organisms: Staphylococcus aureus (two strains), Salmonella senftenberg, S. typhimurium, Escherichia coli, Streptococcus faecalis, Bacillus cereus, Clostridium sporogenes, C. perfringens (two strains). The magnitude of the response varied with the culture, the largest being 3.5 degrees with B. cereus cells. The spores of B. cereus were not protected by salt but clostridial spores behaved as the vegetative cells (response of 2.5 degrees). The optimal salt concentration for the protective effect varied with the organism ranging from 0.2 M for the Gram-negative organisms to 1.0 M for S. aureus.

Bacillaceae↗
PubMed1980

Directional units in the rat optic nerve.

Single units with directional receptive fields were recorded from the rat optic nerve and thus revealed, in contrast to earlier reports, the presence of at least one class of non-concentric retinal unit in this species. In confirmation of prior work, examples of concentric, surround-dominated and centre-dominated receptive fields were also encountered. In some respects their properties resembled those of either brisk or sluggish classes in the cat retina.

Animals↗
PubMed1980

A newly identified population of presumptive microneurones in the cat retinal ganglion cell layer.

A large population of microneurones has recently been discovered in the rabbit retinal ganglion cell layer. These 'coronate' cells may represent a class of displaced amacrine cells. Like conventional amacrine cells they are swiftly and selectively destroyed by low concentrations of kainic acid, a neurotoxin. No similar cell has been described in the cat retina, which is reported to contain 217-260,000 neurones of classical appearance. These outnumber the 128-180,000 optic nerve fibres but it has been suggested that the excess comprise Nissl-staining glial cells. We report here that, using the neurotoxic effects of kainic acid to test and confirm the neuronal nature of the classic neurone excess, a large additional population of at least 730,000 presumptive microneurones was revealed. They resemble rabbit coronate cells, do not project into the optic nerve and have been previously identified as presumed glia. Various lines of evidence for the neuronal nature of these cells is presented below, but synapses have not been demonstrated; subsequent reference to microneurones must therefore be regarded as presumptive.

Animals↗
PubMed1980

Coronate cells: displaced amacrines of the rabbit retina?

The rabbit retinal ganglion cell layer contains a soma population which is morphologically distinct from the demonstrated ganglion cells. These "coronate cells" (Vaney, '80) have many features in common with classical neurons and are qualitatively different from typical glial cells. Detailed investigation by specific staining, ribonuclease treatment, and electron microscopy indicates that coronate cells are microneurons. The coronate cells contain somatic subsurface cisternae typical of rabbit amacrine cells, and are similar in appearance to some neurons of the amacrine cell layer. It is suggested that they represent, at least in part, a population of "displaced" amacrine cells.

Animals↗
PubMed1980

A statistical analysis and comparison of soma diameter spectra for classical neurones from different regions of the cat retinal ganglion cell layer.

Multimodal soma diameter spectra for neurones of the cat retinal ganglion cell layer have been represented by three subpopulations of independent, normal diameter distribution. Recurrent computation according to the technique of Vibert and Caille (1978) has extracted best fit populations for samples from various regions of central and peripheral retina. The model subpopulations from all these regions did not differ significantly in their relative proportions or variance. Significant progressive variation between subpopulations representing different regions of retina were observed only in the mean diameter of the alpha and beta mode cells. The parameters of the gamma mode population were statistically uniform across the retina. The cat retina thus appears to be more homogeneously organized than has been suggested elsewhere.

Animals↗
PubMed1980

The effect of frontal EMG biofeedback training on the behavior of children with activity-level problems.

N = 1 withdrawal designs were employed with three children evidencing activity-level problems. Tutoring sessions occurred daily over a 2 1/2-month period. Each child was reinforced for decreasing frontalis muscle tension during auditory feedback while working arithmetic problems. Feedback was faded while tension reduction reinforcement was maintained. These procedures were repeated with reinforcement for increasing, rather than decreasing, muscle tension. Frontal EMG level, percent time on task, and motoric activity rate were obtained during sessions. Parent ratings of problem behavior in the home were recorded daily. Biofeedback with reinforcement was effective in both raising and lowering muscle tension. Effects were maintained by reinforcement. Results suggest a direct relationship between tension and activity levels. Academic performance and problem behavior improved significantly with reductions in EMG activity, although individual exceptions to these findings were present. Results lend support to the efficacy of frontal EMG biofeedback training in reducing activity, increasing attention to an academic task, and reducing problem behaviors.

Biofeedback, Psychology↗
PubMed1980

Effect of parental head circumference on that of the newborn child.

The head circumferences of 74 term, normal babies were measured, together with the head circumferences of their parents. Maternal head circumference had a significant effect on that of the newborn infant but paternal head circumference had not. An equation is given for estimating the expected head circumference of a newborn infant, provided the birthweight and maternal head circumference are known.

Birth Weight↗
PubMed1980

Platelet monoamine oxidase activity in megaloblastic anaemia.

Platelet monoamine oxidase activity has been measured in 17 patients with megaloblastic anaemia due to either vitamin B12 or folate deficiency, and in 20 healthy subjects. There was a highly significant increase in patients compared with controls. In two patients, platelet activity decreased following successful treatment. A significant correlation between platelet activity and the severity of bone marrow megaloblastic change, assessed by the deoxyuridine suppression test and bone marrow morphology, was also observed. If the change in activity also occurs in the nervous system, this may contribute to the mental disturbance associated with vitamin B12 or folate deficiency.

Anemia, Macrocytic↗
PubMed1980

The effect of NaCl on the upper temperature limit for growth of and enterotoxin synthesis by Staphylococcus aureus.

The upper temperature limit for growth of an enterotoxin A producing strain (MF31) and of an enterotoxin B producing strain (S6) was about 44-45 degrees C in either a peptone-based medium or heart infusion broth. In the presence of NaCl, growth and production of enterotoxin, coagulase, and thermostable nuclease occurred up to 2 degrees C higher. The optimal concentration of NaCl for the temperature elevation effect was 1 M.

Bacterial Toxins↗
PubMed1980

Mechanism of the temperature protective effect of salts on Staphylococcus aureus.

In the previous paper we reported that the maximum temperature for growth of Staphylococcus aureus was about 2 degrees C higher in media supplemented with NaCl. We now show that MgCl2 was the most effective protectant at 0.4 M. NaCl and KCl were as effective as MgCl2 when tested at 1 M. NH4Cl was less effective at all concentrations and LiCl was not protective. Sucrose and glucose (1M) gave about half the biomass of 1M NaCl. Glycerol, Na2SO4, NaNO2, NaNO3, and CH3COONA were not protective. Protection is probably due to the nonpenetrating solute (sucrose) or the nonpenetrating Cl- anion. Mg2+ had an effect additional to that attributable to Cl- because MgSO4 and to a slight extent (CH3COO)2Mg were protective. The morphology of the cells grown at 45 degrees C in 1 M NaCl was abnormal: septation became irregular, cell walls were thickened, and the cells occurred in irregularly sized clumps surrounded by capsular material.

Ammonium Chloride↗