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Biomedical subjects

A H Jackson

Publications and source records attributed to A H Jackson.

At least 19 recordsLinked to original sources
PubMed1988

The isolation and identification of indigoid pigments from urine.

A purple pigment, phyriaviolin, and a blue pigment, phyriaazulin, have been found in relatively large amounts in the urine of patients suffering from two diverse pathological conditions, porphyria cutanea tarda and Crohn's disease. The two pigments have been characterised by chemical, spectroscopic, and chromatographic studies and identified to be indirubin and indigo (indigotin). Possible reasons for their formation are discussed.

Chromatography, Thin Layer↗
PubMed1987

The synthesis of stereoselectively labelled porphobilinogen and its incorporation into protoporphyrin-IX.

11-(R)-2H porphobilinogen, stereospecifically labelled with deuterium in the aminomethylene group has been incorporated into protoporphyrin-IX by haemolysates of chicken erythrocytes. High field NMR spectroscopy confirms that the overall biochemical process is stereospecific, deuterium being retained at the alpha-, gamma- and delta-meso positions and lost from the beta-meso position.

Animals↗
PubMed1984

Sputum sol-phase proteins and elastase activity in patients with cystic fibrosis.

Sputum and serum samples were obtained from 38 patients with cystic fibrosis seen as out-patients at routine follow-up, or from patients admitted with acute pulmonary exacerbations of their disease. Elastolytic activity was measurable in the sputum of 13 of 16 out-patient samples and detectable in 21 of 22 patients admitted with pulmonary exacerbation. The enzyme activity was inhibited by soy bean trypsin inhibitor and alpha 1 antitrypsin, but not by ethylenediamine tetracetic acid, suggesting that it was predominantly a serine proteinase, probably leucocyte elastase. The mean sputum/serum albumin ratio was 2.53 X 10(-2) (SD +/- 2.4) for the out-patients and this was not significantly different from those of patients admitted with pulmonary exacerbation. However, those patients admitted with fever had increased sputum/serum albumin ratios (mean = 4.66 X 10(-2); SD +/- 3.19) compared with those admitted with a normal temperature (mean = 1.52 X 10(-2); SD +/- 0.41. 2p less than 0.01). The albumin ratios of the pyrexial group fell with antibiotic therapy. The sputum/serum alpha 1 antitrypsin ratios were generally greater than expected (by comparison with albumin) and evidence is presented suggesting that this is due to immunological over-estimation.

Adolescent↗
PubMed1984

Apnea documentation for determination of brain death in children.

Discontinuing ventilatory support for determination of respiratory drive is a recognized means of assessing clinical brain death. Methodology must include a means for assuring adequate oxygenation during the test as well as providing sufficient duration for appropriate hypercarbia. Nine patients with other findings of clinical brain death were prospectively assessed with a standardized apnea test protocol. None demonstrated spontaneous respirations. Whereas adequate oxygenation was maintained in each case, wide variability was evident in degree of hypercarbia and acidosis.

Apnea↗
PubMed1983

Brain death in the pediatric intensive care unit. A clinical definition.

The establishment of criteria for brain death is important for decision making in the treatment of critically ill patients. Our experience involving 15 children with coma, apnea, and absent brain-stem reflexes for a period of greater than three days supports previous reports in adults that the diagnosis of brain death can be made by clinical criteria alone. None of these patients survived, and each of the 11 autopsies performed revealed marked liquefactive necrosis in the brain.

Adolescent↗
PubMed1983

Reproducibility of saliva and plasma theophylline levels following single dose administration of two sustained release preparations.

1 Concomitant saliva and plasma theophylline concentrations were measured in six healthy male volunteers following single dose administration of two sustained release preparations (Nuelin SA and Phyllocontin Continus). 2 Using mean values, a good correlation was obtained between saliva and plasma drug concentrations. Prediction of plasma values using individual saliva was poor and varied widely. The ratio of saliva to plasma concentrations in the same individual, assessed under standardised conditions, was not always reproducible.

Adult↗
PubMed1983

The comparative bioavailability of slow release oral theophylline preparations.

Plasma concentrations of theophylline were determined in healthy volunteers following a single oral dose of six slow release preparations, immediately following a standard breakfast. There were no significant differences between the different preparations. The time taken to reach maximum plasma concentration, tmax, was found to be longer than in previous studies in which the drug was administered on an empty stomach.

Administration, Oral↗
PubMed1983

Psychiatrists' responses to violence: pharmacologic management of psychiatric inpatients.

Court decisions setting limits on the use of medication in psychiatric hospitals often assume that psychiatrists use medications inappropriately in response to patients' violent acts. No empirical data have existed to support or refute this assumption. The authors examined the types and doses of antipsychotic medications received by 45 violent patients and 48 control subjects. They found no significant differences in type and dose of medication before the violent act and no significant changes afterward. Violent patients tended to be on somewhat higher doses at discharge than control patients. The judicial concern that psychotropic medications will automatically be abused or overused is not supported by these results.

Antipsychotic Agents↗
PubMed1982

Separation of impurities in diazinon preparations and their effect on porphyrin biosynthesis in tissue culture.

The impurities present in commercial diazinon preparations have been examined by high performance liquid chromatography with particular reference to the ability of these compounds to cause porphyrin accumulation in cultures of chicken embryo liver cells. Diazinon and its impurities are readily separated on 10 micron Partisil using cyclohexane-dioxan mixtures. The main impurities are tetraethylpyrophosphate, sulphotetraethylpyrophosphate, 2-isopropyl-6-methylpyrimid-4-one, 2-isopropyl-6-methylpyrimidin-4-thione, and 2-isopropyl-4-ethylthio-6-methylpyrimidine. A previously unreported impurity, 2-isopropyl-6-methyl-4-S-pyrimidinyl diethylthiophosphate (isodiazinon), was also detected. Both diazinon and isodiazinon cause accumulation of coproporphyrin in cultures of chicken embryo liver cells. Isodiazinon has a greater effect on porphyrin biosynthesis in the cultures than has diazinon. It is suggested that the point of interference with porphyrin biosynthesis is towards the end of the pathway.

Animals↗
PubMed1981

Acute mercury vapor poisoning. Fatality in an infant.

A 7-month-old girl succumbed to respiratory failure following exposure to high-density mercury vapor produced by heating of the metal in the home. Her course typified inhalation mercury toxic reaction, which in its focus on pulmonary damage creates a clinical picture distinct from that of chronic and oral mercury poisoning.

Accidents, Home↗