Biomedical subjects

L J Hands

Publications and source records attributed to L J Hands.

40 records · Page 3Linked to original sources

PubMed1985

Vitamin K requirements in patients receiving total parenteral nutrition.

The vitamin K requirements of 47 adult patients on total parenteral nutrition (TPN) were investigated by randomly allocating them to receive either 0.15 mg vitamin K1 (1 ampoule of 'Vitlipid') per week or 20.15 mg vitamin K1 (1 ampoule of 'Vitlipid' plus 10 mg vitamin K X 2) per week. Vitamin K1 in a dose of 0.15 mg was as effective as a dose of 20.15 mg per week in maintaining a normal BCR (British Corrected Ratio) in most TPN patients. Seven patients in each group developed a BCR greater than 1.3; this was significantly associated with the use of cephalosporin antibiotics and responded to 10 mg vitamin K1 per day. Most patients receiving parenteral feeding require no more vitamin K than that provided by 1 ampoule of 'Vitlipid' per week. Regular monitoring of the BCR, especially in patients on antibiotics, will reveal those who need more. Such patients need 10 mg vitamin K1 per day.

Adolescent↗

PubMedDate not supplied

Quantitative analysis by 31P magnetic resonance spectroscopy of abnormal mitochondrial oxidation in skeletal muscle during recovery from exercise.

We use the hyperbolic relationship between cytosolic [ADP] and the rate of phosphocreatine (PCr) resynthesis after exercise to estimate the apparent maximum rate of oxidative ATP synthesis (QMAX). We examine data from some human diseases in which mitochondrial oxidation may be impaired (due to reduced mitochondrial numbers, intrinsic mitochondrial defect or impaired vascular supply). Muscle responds to impaired oxidation by stimulating anaerobic ATP synthesis and/or by increasing [ADP], the stimulus to the mitochondrion. However, these responses interact: [ADP] depends on pH and [PCr], and lactic acid production tends to lower [ADP] (by lowering pH), while proton efflux has the opposite effect. We identify four patterns of results: (A) in mitochondrial myopathy, apparent QMAX is reduced and [ADP] is appropriately increased, because increased proton efflux reduces the pH change in exercise despite increased lactic acid production; (B) in some conditions (e.g., cyanotic congenital heart disease) apparent QMAX is reduced but there is no compensatory rise in [ADP], probably because anaerobic ATP synthesis during exercise is increased without increase in proton efflux; (C) in other conditions (e.g., myotonic dystrophy) [ADP] is increased during exercise but apparent QMAX is normal, suggesting either an increase in proton efflux and/or decrease in anaerobic ATP synthesis during exercise; (D) there are also conditions (e.g., respiratory failure) where, despite impaired oxygen supply, both apparent QMAX and end-exercise [ADP] are normal. We also discuss the metabolic conditions under which end-exercise [ADP] is increased by a mitochondrial defect.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate↗

PubMedDate not supplied

Thromboelastographic changes following nonionic contrast medium injection during transfemoral angiography in patients with peripheral arterial occlusive disease.

BACKGROUND/PURPOSE: Patients with peripheral arterial occlusive disease (PAOD) are known to be systemically hypercoagulable and there is concern that exposing them to contrast media during angiography may exacerbate that thrombotic tendency. Many in vitro studies in which blood is exposed to contrast media suggest that nonionic contrast medium (NICM) has a weaker anticoagulant effect than ionic contrast medium (ICM) and some studies suggest that NICM can lead to activation of coagulation thus increasing the risk of thrombotic events where it is employed. We have looked at the changes in coagulation adjacent to the site of contrast injection/potential angioplasty to determine the magnitude of change locally. METHODS: We measured changes in the coagulability of aortic blood samples immediately before and within 2 min after injection of the last bolus of iohexol (NICM) prior to any intervention procedure in 30 patients with PAOD. Samples were analyzed using thromboelastography (TEG) to identify changes in the coagulability of the aortic blood samples. RESULTS: TEG tracings of samples taken from the aorta after injection of NICM showed a significant increase in R time (time to fibrin formation) (p = 0.036) and in k time (dynamics of clot formation) (p = 0.028) and a reduction in Angle (decreased acceleration of fibrin build-up) (p = 0.013), Maximal amplitude (MA) (reduced ultimate clot strength) (p = 0.018) and Coagulation Index (CI) (p = 0.032). CONCLUSION: These changes in TEG parameters show that the local effect of NICM is a reduction in coagulation activity rather than the activation suggested by some previous studies.

Aged↗

PubMedDate not supplied

Total parental nutrition using conventional and medium chain triglycerides: effect on liver function tests, complement, and nitrogen balance.

Conventional long chain triglyceride (LCT) was compared with a new emulsion containing 50% medium chain triglyceride (5% MCT/5% LCT) in a randomized cross-over trial of 10 days duration. Plasma concentrations of albumin, prealbumin, the complement components C3 and C4, and prothrombin times measured daily at 8 am, before lipid infusion, showed no progressive change during the 10 days of the trial, nor in each separate 5-day period when LCT or MCT/LCT was infused. Aspartate transaminase and alkaline phosphatase activities were similar over the two periods. There was a significant increase (compared with preinfusion levels) in C3 and C4 levels after 5 hr of either lipid infusion. Nitrogen balance was improved, and plasma bilirubin levels were lower on the regimen containing MCT/LCT.

Adult↗