Search PubMed⌕ Search

Biomedical subjects

L Loh

Publications and source records attributed to L Loh.

At least 73 records · Page 4Linked to original sources
PubMed1978

Multiple interactions between murine cytomegalovirus and lymphoid cells in vitro.

Spleen cultures from various strains of mice were infected in vitro with murine cytomegalovirus (MCMV). Infectious centres were established in a small proportion (not greater than 1%) of the cells. Virus could be rescued from these cells by co-cultivation with syngeneic or allogeneic fibroblasts, but the frequency of rescue could not be altered by incubation with cyclic nucleotide analogues, iododeoxyuridine, cortisol, or allogeneic spleen cells. In addition a smaller fraction of the cell population, possibly a sub-population of the infectious centres, replicated virus spontaneously. The presence of mitogens did not affect these interactions qualitatively or quantitatively. A third response to infection was an inhibition in DNA synthesis, which was suffered by unstimulated cultures and by cells transformed by concanavalin A and bacterial lipopolysaccharides, although overall cell viability was maintained. This response was also mediated by u.v.-inactivated virus.

Animals↗
PubMed1978

Diagnosis of subdural haematoma by computed axial tomography: use of xenon inhalation for contrast enhancement.

A subdural haematoma is described in which a definite computed tomographic (CT) scan diagnosis was made only after contrast enhancement had been achieved by the inhalation of xenon. The different types of enhancement obtained with iodide containing contrast media and with xenon are discussed. The use of xenon to obtain further information in conditions which are inadequately elucidated by conventional CT must be balanced against its anaesthetic effects and relatively high cost.

Contrast Media↗
PubMed1978

Painful peripheral states and sympathetic blocks.

In various chronic painful states, the sympathetic nerve supply was blocked either by injecting the sympathetic chain and ganglia with local anaesthesia or by the injection of guanethidine during occlusion of the circulation. There was a striking relation between the presence of hyperpathia and the relief of pain by the blocks. The sympathetic block was unlikely to relieve the pain unless hyperpathia accompanied the pain; when hyperpathia was present, a sympathetic block relieved both the constant pain and the hyperpathia. The effectiveness of the guanethidine blocks shows that the pain and the hyperpathia are maintained by the emission of noradrenaline in the periphery. The facts related to the sympathetic system and sensibility are discussed.

Anesthesia, Local↗
PubMed1977

Reduction of hypoxic pulmonary vasoconstriction by nitrous oxide administration in the isolated perfused cat lung.

Local pulmonary vasconstriction in response to alveolar hypoxia is a protective mechanism reducing blood flow to poorly oxygenated areas of lung. Pulmonary blood flow is thereby directed to better oxygenated lung units and venous admixture and the resulting arterial hypoxaemia is reduced. The effect of nitrous oxide on the pulmonary pressor response to alveolar hypoxia was assessed in the isolated perfused cat lung preparation under conditions of constant flow and constant left atrial and airway pressures. Nitrous oxide, in concentrations of 50 per cent and 75 per cent, was found to produce a reversible depression of the hypoxic pulmonary pressor response. The importance of hypoxia pulmonary vasconstriction and the possible implications of its reduction by anaesthetic agents are discussed.

Animals↗
PubMed1977

Evaluation of a new method for the continuous measurement of the distribution of the blood flow between the two lungs.

The magnitude of the pulmonary vasoconstrictor response to alveolar hypoxia may be studied by measuring the reduction in blood flow when one lung is ventilated with nitrogen. A radioisotope technique has been developed which permits the distribution of blood flow between the two lungs to be measured continuously. This technique was evaluated in dogs and found to be satisfactory.

Animals↗
PubMed1977

The effects of halothane and ether on the pulmonary circulation in the innervated perfused cat lung.

The effects of halothane and diethyl ether on pulmonary vascular resistance and the pulmonary vasoconstrictor response to alveolar hypoxia were studied in the innervated perfused cat lung. A left and right heart bypass technique was used to allow perfusion of the lungs at constant flow. Neither anaesthetic agent caused a significant change in pulmonary vascular resistance but both agents caused a depression of the pulmonary vasoconstrictor response to hypoxia.

Animals↗
PubMed1977

The assessment of diaphragm function.

Paralysis or severe weakness of the diaphragm (the principal muscle of inspiration) is commonly associated with hypoventilation which may be profound during sleep, but the disorder is often unrecognized. The clinical sign of paradoxical (inward) movement of the abdominal wall during spontaneous inspiration in the supine posture may be overlooked, or the appearances at fluoroscopy may mislead, for it is not generally appreciated that descent of the diaphragm in early inspiration in these patients may be an entirely passive event. Measurement of transdiaphragmatic pressure is a simple, reliable and quantitative means of assessing diaphragm function, and will aid in the diagnosis of diaphragm paralysis which has important implications for clinical management.

Diaphragm↗
PubMed1977

Effects of general anaesthesia on size of cerebrospinal fluid spaces during and after pneumoencephalography.

The mode of anaesthesia used during pneumoencephalography has a significant effect on the size of the cerebral ventricles 24 hours after the procedure. Post-encephalographic ventricular enlargement is less marked in patients examined under nitrous oxide anaesthesia. This appears to be related to passage of the gas into the ventricles during the encephalogram, and subsequent diffusion outwards. Variations in arterial carbon dioxide tension during the anaesthesia do not contribute significantly to changes in ventricular size. However, both hyperventilation and inhalation of nitrous oxide may cause apparent increase in size of the cerebral sulci.

Anesthesia, Inhalation↗
PubMed1976

Diaphragm function and alveolar hypoventilation.

A syndrome of alveolar hypoventilation has been identified in a group of patients with bilateral diaphragm paralysis. Eight patients were studied in whom diaphragm weakness had been suggested by paradoxical (inward) movement of the abdominal wall on inspiration, of whom seven had evidence of a generalized neuromuscular disorder. Diaphragm function was assessed quantitatively by measurement of the change in transdiaphragmatic pressure during a maximum inspiration (deltaPDi). In five patients, deltaPDi was zero and in the others ranged from 2-6 cm H2O (normal greater than 25 cm H2O) indicating paralysis and severe weakness in the respective groups. Fluoroscopy of the diaphragm was found to give misleading results, and the resons for this are considered. Vital capacity ranged from 65-30 per cent of the predicted normal in the upright posture, typically falling by about a half in the supine posture. Alveolar hypoventilation was present in five patients when supine and in six when asleep, the deterioration in blood gases associated with sleep generally being much greater in these patients than in normal subjects. Respiratory rate was significantly greater than age-matched controls. The ventilatory response to CO2 was impaired. The PCO2 could be brought to normal levels by voluntary hyperventilation, and the unreliability of voluntary respiratory manoeuvres of this kind as indices of ventilatory reserve is emphasized. Alveolar hypoventilation was associated with disturbed sleep, morning headache and day-time fatigue. Symptomatic benefit was achieved by the use of a cuirass respirator at night.

Adult↗
PubMed1975

Chlormethiazole in treatment of status epilepticus.

Chlormethiazole (Heminevrin) was successful in controlling fits in seven out of nine episodes of intractable status epilepticus. It was administered as a constant intravenous injection at rates of up to 0.7g/h. No serious side effects were encountered, and the drug deserves wider recognition as a useful therapeutic agent in the management of status epilepticus.

Adolescent↗
PubMed1974

Closing volume and pregnancy.

Measurements of closing volume have been made in 20 women between the 36th and 40th weeks of pregnancy. The patients were studied in the erect and supine positions and the point of airway closure was related to functional residual capacity. The results show that airway closure occurred during tidal ventilation in 10 patients in the erect position and in six patients in the supine position. These results may explain the variation found in maternal arterial oxygen tension during pregnancy.

Arteries↗