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Biomedical subjects

D Simpson

Publications and source records attributed to D Simpson.

At least 217 records · Page 12Linked to original sources
PubMed1988

The toxic effects of alpha-chloralose.

1. Alpha-chloralose, formed by the condensation of glucose with chloral, is used as a rodenticide and in the control of bird pests. 2. In two cases of poisoning with alpha-chloralose the clinical features included coma and generalized convulsions resembling the effects of strychnine more than those of chloral hydrate. 3. The principles of management are the support of vital functions in the unconscious patient and removal of unabsorbed poison by gastric lavage. Diazepam may be used to control convulsions.

Adolescent↗
PubMed1987

Chlorophyll-protein complexes of barley photosystem I.

Photosystem I (PSI) preparations with a chlorophyll a/b ratio of 6.0 were isolated from barley thylakoids using two different methods. The high-molecular-mass complex (CP1a) which is resolved by non-denaturing gel electrophoresis had the same properties as a PSI preparation (PSI-200) isolated by Triton X-100 solubilisation of thylakoids followed by sucrose gradient ultracentrifugation. This material had a chlorophyll:P700 ratio of 208:1 and was composed of three different chlorophyll-protein complexes which could be separated from each other by solubilising the PSI preparation in dodecyl maltoside followed by sucrose gradient ultracentrifugation. Approximately half of the chlorophyll, including all the chlorophyll b, was located in two antenna complexes designated LHCI-680 and LHCI-730, which were identified by their characteristic low-temperature fluorescence emission spectra. The rest of the chlorophyll a was associated with the PSI reaction centre, P700 Chla-P1, which fluoresced at 720 nm. Each chlorophyll-protein complex had a unique polypeptide composition and characteristic circular dichroic and absorption spectra. The use of dodecyl maltoside instead of dodecyl sulphate resulted in a less denatured form of LHCI-680, which fluoresced at 690 nm at 77 K. One of the sucrose gradient fractions contained a complex consisting of only LHCI-730 and P700 Chla-P1 which fluoresced at 731 nm, indicating that LHCI-730 is structurally associated with P700 Chla-P1 and quenches its fluorescence. Approximately three-quarters of the light-harvesting antenna chlorophyll was in LHCI-730, but only about one-quarter of the normal complement of LHCI-730 was required to quench the reaction centre. By reducing the amount of Triton relative to the chlorophyll concentration, a PSI preparation (chlorophyll a/b ratio of 3.5) with a chlorophyll:P700 ratio of 300:1 was isolated. It contained no photosystem II, but a significant amount of LHCII which was functionally connected to the PSI reaction centre. Reconstitution studies demonstrated that excitation energy transfer from LHCII to PSI requires the presence of LHCI-680, and we propose that, in PSI, the following linear excitation energy transfer sequence occurs: LHCII----LHCI-680----LHCI-730----P700 Chla-P1.

Centrifugation, Density Gradient↗
PubMed1987

Risk of AIDS-related virus (human immunodeficiency virus) transmission through apheresis procedures.

Since exposure to blood products occurs on a daily basis during hemapheresis, the acquired immunodeficiency syndrome (AIDS) epidemic has a serious impact both for patients undergoing apheresis procedures as well as for health professionals working in the field. We studied serum samples from 110 patients who underwent therapeutic plasmapheresis for a variety of diseases not related to AIDS for the presence of antibodies to human immunodeficiency virus (HIV). Exchange fluids used in the majority of the patients were plasma protein fraction and 5% human albumin. Four patients received only fresh-frozen plasma. Fifty-five patients also received IV gammaglobulin. The follow-up period exceeded 24 months. All patients who did not belong to any known high-risk group for AIDS were negative for HIV antibodies prior to treatment and remained negative at last follow-up. Seven patients were homosexual men. All seven were seropositive prior to plasmapheresis and remained so throughout the treatment period. Seven health professional working in a busy haemapheresis unit were followed for 2 1/2 years. All remain HIV seronegative with normal immune function. These data indicate that transmission of HIV is unlikely through haemapheresis procedures.

Acquired Immunodeficiency Syndrome↗
PubMed1987

A multicenter validation of the prehospital index.

The prehospital index (PHI) is a triage-oriented trauma severity scoring system. This prospective multicenter validation of the PHI was undertaken in response to a favorable pilot study. We applied the PHI to 3,581 patients from 14 different institutions during the period from January 1985 to February 1986. The PHI was accurate in predicting the need for emergency life-saving surgery within four hours (P less than .0001) and mortality within 72 hours (P less than .0001) following traumatic injury. The curves were generated for PHI versus emergency surgery, mortality, surgery and mortality, injury severity score, and ICU admission rate. These data compare favorably with those from previously published, prospectively tested, triage-oriented trauma severity scoring systems.

Clinical Trials as Topic↗
PubMed1987

Plasma salicylate analysis: a comparison of colorimetric, HPLC and enzymatic techniques.

Three colorimetric techniques and one enzymatic technique have been compared with an HPLC method for the analysis of salicylate in the plasma of patients after self-poisoning with aspirin. The enzymatic technique was specific but expensive to perform. The colorimetric techniques were simple, cheap and precise. The Keller method, however, was susceptible to interference from endogenous substances. We report a modification of the Keller method that eliminates most of this interference and improves the accuracy of the analysis. The new method is easier and safer to perform under emergency conditions than the Trinder technique.

Chromatography, High Pressure Liquid↗
PubMed1987

Self-poisoning and therapeutic intoxication with lithium.

Of 68 admissions for lithium overdose over 16 years, 25 were due to therapeutic intoxication and 43 to deliberate self-poisoning. Three patients with therapeutic intoxication had acute diabetes insipidus with hypernatraemia. One of them had acute renal failure requiring dialysis, prolonged Parkinsonism and generalised myopathy. Twenty-two patients with therapeutic intoxication had peak serum lithium concentrations above the therapeutic range. In contrast, of 22 self-poisoned patients with peak serum lithium concentrations above the therapeutic range only 3 developed toxicity. The mean admission plasma urea concentration in patients with therapeutic intoxication was higher than in self-poisoned patients and the mean admission plasma bicarbonate concentration was lower. The mean serum lithium half-life in 8 patients with therapeutic intoxication was considerably longer than in 5 self-poisoned patients. Renal lithium clearance is enhanced by increased sodium excretion and we recommend that lithium toxicity be treated with saline diuresis and frusemide if fluid retention occurs. Haemodialysis is mandatory when renal failure is present, and may be indicated when serum lithium concentrations are very high or rising rapidly.

Adolescent↗
PubMed1987

Toxicological screening in heroin users: implications for management of drug misuse.

The toxicological screening of 200 urine samples from 55 known heroin users claiming to be abstinent revealed that in 18% of samples (24% of users tested) opiates were unexpectedly detected. Other substances, many of which were psychoactive drugs, were identified in 35% of samples. Cocaine was not detected in any samples. In addition, nicotine was found in 91% of users and caffeine in 44%. The data showed the presence of polydrug abuse in 29% of subjects and suggested there is an illegal supply of drugs originating from doctors' prescriptions. The requirement for more general use of toxicological screening and the implications of the results for management of drug takers in general practices are discussed.

Female↗
PubMed1986

High frequency jet ventilation in fat embolism syndrome.

The use of high frequency jet ventilation in the management of a patient with fat embolism syndrome is described. Its principal advantage over conventional intermittent positive pressure ventilation is a reduction in the amount of sedation necessary.

Adult↗
PubMed1986

Neurotrauma.

Explore the source record for details and available documents.

Australia↗
PubMed1986

Experience with chronic subdural haematomas in New South Wales.

This study considered 135 cases of chronic subdural haematoma following head injury in 1977 and 1978. The majority were in the older age group and more often males. Falls were the commonest cause. Among intracranial haematomas they carry a much better prognosis. However, there was a mortality rate of 9% and delay in diagnosis was the most likely preventable factor contributing to this. Accordingly the possibility of this complication after head injury should be known to those concerned in the later hospital treatment and follow-up management especially of older patients and alcoholics. When the diagnosis has been made, the preferred surgical method of treatment is drainage through burrholes. Follow-up CT scanning should be arranged usually about 8 weeks afterwards unless there are clinical indications for an earlier examination.

Adolescent↗
PubMed1986

Drug screening: evaluation of the Toxi-Lab TLC system.

An evaluation of a commercial TLC Kit System (Toxi-Lab) is described. The performance of the system is assessed in the detection of drugs in overdose and in therapy, and is compared with a GC drug screening system. Toxi-Lab performed well in investigating drug overdoses. We found data on metabolite patterns essential for the identification of drugs in urine and for this reason the system performed much better than GC screening in which information on metabolites is limited. In our experience Toxi-Lab screening was not sufficiently sensitive for the detection of commonly prescribed psychiatric drugs taken in therapeutic doses. This system is rapid, versatile and suitable for small laboratories, but is comparatively expensive and some expertise is necessary to interpret results. A major deficiency of the kit is that the identification procedures are designed for the detection of drugs available in the USA and many drugs prescribed in the UK have been omitted.

Antidepressive Agents↗