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Biomedical subjects

S Karran

Publications and source records attributed to S Karran.

7 recordsLinked to original sources
PubMed1993

Vitamin K coagulation status in surgical newborns and the risk of bleeding.

The vitamin K coagulation status in surgical newborns, who may be at increased risk of developing hypocoagulability and hemorrhage, has not previously been studied. Therefore, we measured the combined activity of the plasma vitamin K-dependent coagulation factors (Thrombotest), total prothrombin, PIVKA II, plasma vitamin K1, fibrinogen, D-Dimer, and platelets in 49 newborns admitted to a neonatal surgical intensive care unit. All infants had significant pathology, and treatment involved surgery in all but two. Twenty-three infants (47%) underwent surgery on two or more occasions. Intravenous or oral antibiotics were used in all patients and many received more than one course. All infants had vitamin K1 prophylaxis at birth. At day 0 (date of birth), the mean Thrombotest and total prothrombin levels were 51% (range, 20% to 100%) and 40% (range, 24% to 59%), respectively. Coagulation activity decreased on day 1 (P > .1) and was followed by a graduate increase in clotting activity, reaching normal adult levels (> 60%) at day 5 for Thrombotest and day 24 for total prothrombin. Only three infants had a Thrombotest less than 20%. PIVKA II was detected in 20 cases (41%). However, levels were within normal limits (< 0.9%) in 17 of these, and between 1.0 and 4.8% in the remaining three infants. There was no relationship between elevated PIVKA levels and coagulation activity in these patients. Plasma vitamin K1 was very high, particularly in the first days of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Birth Weight↗
PubMed1990

Progress in the assessment of liver blood flow in health and disease.

Several of the reasons why the liver is a vital organ are illustrated in this review. The fundamental importance of its dual arterial and portal venous supply is shown in a wide range of physiological and pathological conditions, ranging from digestion to regeneration, cirrhosis, mesenteric ischaemia and malignancy. In most, if not all, of these functions the blood supply exerts an important, if not prime, role. This article reviews some of the progress made in evaluating these vital hepatic circulatory phenomena.

Humans↗
PubMed1987

Changes in blood flow, portal pressure and shunting during the development of cirrhosis in response to beta-blockade.

An experimental model of cirrhosis was developed in the rat to assess the effect of disease and pharmacological manipulation on blood flow, shunting and portal pressure. With progression in the severity of histological cirrhosis there was a steady fall in effective liver blood flow as measured with radioisotope labelled colloid. This corresponded to a rise in portal pressure and shunting with a close correlation between the two (r = 0.7, p less than 0.01). In control animals and when portal hypertension was caused by extrahepatic obstruction, beta-blockade with propranolol, but not selective beta 2 blockade, significantly decreased liver blood flow. With cirrhosis there was a variable response to propranolol depending on the histological severity of disease, the height of portal pressure and degree of shunting. There is a possibility therefore that a potential may exist for lowering portal pressure by manipulating intrahepatic shunting.

Adrenergic beta-Antagonists↗
PubMed1979

Lipid metabolites and nitrogen balance after abdominal surgery in man.

The relation of lipid metabolism to nitrogen balance was studied in patients having undergone abdominal surgery and was compared with control subjects who had fasted for a similar period. The patients had lower circulating concentrations of glycerol, non-esterified fatty acids and ketone bodies. There were inverse correlations between blood alanine and ketone body concentrations in both patients (r = -0.64, P less than 0.01) and controls (r = -0.58, P less than 0.01). Nitrogen excretion by patients (12.7 mmol/kg body weight/day +/- 1.4 s.e. mean) was greater than by controls (9.2 mmol kg(-1)d(-1) +/- 0.8, P less than 0.05), but a more marked difference was noted for urinary methyl histidine excretion of 5.1 +/- 0.5 mmumol kg(-1) d(-1) by patients and only 2.5 +/- 0.3 mumol kg(-1) d(-1) by controls (P less than 0.01), a disparity indicative of more active protein turnover after surgery.

Abdomen↗