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Biomedical subjects

J Sinclair

Publications and source records attributed to J Sinclair.

At least 91 records · Page 5Linked to original sources
PubMed1973

Reporting of post-transfusion jaundice.

Reports of post-transfusion jaundice were analysed in four successive years from April 1, 1969 to April 1, 1973. Analysis showed a marked reduction in the number of cases reported during the two years of routine HBAg-testing of all blood donations as compared with the two years before this testing was instituted. The value of retrospective studies under present conditions of reporting is discussed.

Blood Banks↗
PubMed1973

Frequency of hepatitis B antigen in blood donors.

Routine testing of all blood donations for hepatitis B antigen by counter-immunoelectrophoresis was started in April 1971. The frequency of HBAg carriers among apparently healthy volunteer blood donors in the Toronto Centre of the Canadian Red Cross Blood Transfusion Service was 15 in 10,000 with a male:female ratio of 6:1. Excluding penitentiary inmates, the highest incidence was among young, male, non-Anglo-Saxon city dwellers.A system of notification of HBAg-positive donors was developed, through which a carrier is referred to a special clinic for clinical and pathological evaluation.A survey of hospital patients indicated an incidence of HB antigen 3.5 times that of our healthy donor population. A comparison of the number of post-transfusion hepatitis cases occurring before and after the commencement of routine testing for HBAg showed a marked reduction in reported cases in 1971.

Adolescent↗
PubMed1972

Reversible abolition of enhancement in isolated spinach chloroplasts.

The photosynthetic evolution of oxygen by isolated chloroplasts of Spinacia oleracea L. was studied using a modulated oxygen electrode. The enhancement effect, measured as the increase in the relative quantum yield of 650-nanometer light due to the presence of 710-nanometer light, was profoundly influenced by the concentration of inorganic cations in the bathing medium. Chloroplast fragments immersed in a solution containing a very low concentration of MgCl(2) or KCl, did not display enhancement but could be made to do so by raising the concentration of MgCl(2) to 3 mm, or that of KCl to 35 mm. This change in the enhancement properties was completely reversible. The maximum value of enhancement in a MgCl(2) solution appeared to occur at a concentration between 15 and 30 mm, while in KCl, the enhancement effect increased almost linearly up to a concentration of 100 mm.The appearance of the initial oxygen transient, the burst, was also controlled by the concentration of inorganic cations. Increasing concentrations of MgCl(2) or KCl caused the burst to grow in size in a way which was linearly related to the corresponding increase in enhancement.

Journal Article↗
PubMedDate not supplied

Astroglia and glutamate in physiology and pathology: aspects on glutamate transport, glutamate-induced cell swelling and gap-junction communication.

Astroglia have the capacity to monitor extracellular glutamate (Glu) and maintain it at low levels, metabolize Glu, or release it back into the extracellular space. Glu can induce an increase in astroglial cell volume with a resulting decrease of the extracellular space, and thereby alter the concentration of extracellular substances. Many lines of evidence show that K(+) can be buffered within the astroglial gap-junction-coupled network, and recent results show that gap junctions are permeable for Glu. All these events occur dynamically: the astroglial network has the capacity to interfere actively with neurotransmission, thereby contributing to a high signal-to-noise ratio for the Glu transmission. High-quality neuronal messages during normal physiology can then be maintained. With the same mechanisms, astroglia might exert a neuroprotective function in situations of moderately increased extracellular Glu concentrations, i.e., corresponding to conditions of pathological hyper-excitability, or corresponding to early stages of an acute brain injury. If the astroglial functions are failing, neuronal dysfunction can be reinforced.

Animals↗