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Biomedical subjects

A R Bird

Publications and source records attributed to A R Bird.

At least 37 records · Page 2Linked to original sources
PubMed1993

Disordered hemostasis in extrahepatic portal hypertension.

To assess the contribution of naturally occurring portal-systemic shunts to the coagulopathy of patients with liver disease, we studied laboratory parameters of hemostasis in 20 adult patients with extrahepatic portal hypertension, secondary to portal vein thrombosis, that had resulted in variceal bleeding. All extrahepatic portal hypertension patients had normal liver function and histological appearance. None had any evidence of preexisting coagulation disorders, and none had bled or undergone sclerotherapy in the 6 mo before study. Age- and gender-matched groups of 20 healthy individuals and 20 stable patients with cirrhosis and portal hypertension who had a history of variceal bleeding served as controls. Both patient groups had thrombocytopenia consistent with hypersplenism and portal hypertension. Prothrombin international normalized ratio (extrahepatic portal hypertension, 1.3 +/- 0.12; cirrhosis, 1.7 +/- 0.2; control, 1.02 +/- 0.06; p < 0.05) and partial thromboplastin time ratios (extrahepatic portal hypertension, 1.12 +/- 0.1; cirrhosis, 1.26 +/- 0.2; controls, 1.01 +/- 0.03; p < 0.05) were significantly prolonged in both patient groups. Extrahepatic portal hypertension and cirrhotic patient groups had significantly increased levels of serum total fibrin(ogen)-related antigen (extrahepatic portal hypertension, 818 +/- 150 ng/ml; cirrhosis, 454 +/- 52 ng/ml; controls, 124 +/- 7.3 ng/ml; p < 0.05), fibrin monomer (extrahepatic portal hypertension, 168.8 +/- 16.9 ng/ml; cirrhosis, 115.6 +/- 11.1 ng/ml; controls, 19.7 +/- 0.4 ng/ml; p < 0.05) and D-dimer (extrahepatic portal hypertension, 118 +/- 9.6 ng/ml; cirrhosis, 129 +/- 10 ng/ml; controls, 53.2 +/- 1.6 ng/ml; p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Tropical pasture hay utilization with slaframine and cottonseed meal: ruminal characteristics and digesta passage in wethers.

Sixteen mature, ruminally cannulated wethers (average BW = 41 +/- 1 kg) were fed a low-quality hay diet with or without a cottonseed meal (CSM) supplement and the parasympathomimetic agonist slaframine (SF). Treatments were basal diet (Mitchell grass hay, 4.8% CP, 46.8% ADF) available on an ad libitum basis, basal diet plus SF (8 micrograms/kg BW, 2 x daily i.m. injection), basal diet plus CSM (41.0% CP; 100 g/d), or basal diet plus SF and CSM. Treatments were arranged as a 2 x 2 factorial within a replicated 4 x 4 Latin square with 20-d periods followed by a 10-d adjustment during which only the basal diet was fed. All measurements were performed within the final 10 d of each period. Slaframine increased salivary flow by 10 to 35% (P < .07), ruminal fluid dilution rate by 8 to 11% (P < .10), and pH by 3 to 4% (P < .001). A twofold increase (P < .05) in ruminal cellulolytic bacteria numbers occurred in SF-treated wethers. Despite these SF-induced changes in the ruminal environment, whole-tract apparent nutrient digestibility, N and mineral balance, and ruminal VFA concentrations were not changed. Cottonseed meal increased forage intake by 34 to 54% (P < .001) and DM digestibility by 30% (P < .001). Cottonseed meal supplementation of a Mitchell grass hay diet improved nutritional status and attenuated live weight loss.

Alkaloids↗
PubMed1993

Manipulation of gastrointestinal nutrient delivery in livestock.

Discussed herein are the constraints of nutrient delivery from the gastrointestinal tract that are placed on postabsorptive synthetic processes in highly selected strains of domestic livestock or livestock treated with growth promotants exogenously or via transgenic manipulation. Emphasis is placed on the discussion of recent advances in the knowledge of the regulation and manipulation of digestion and the absorption by the intestinal epithelium. Slaframine, a muscarinic exocrine secretagogue with a high affinity for the gastrointestinal tract, and epidermal growth factor may have practical potential for the manipulation of digestion and absorption, respectively. Special consideration is given to energetic considerations that must accompany any manipulation of gastrointestinal function. Down-regulation and up-regulation of mechanisms must be equally considered as this area is explored further.

Animal Nutritional Physiological Phenomena↗
PubMed1993

The prevalence of antiphospholipid antibodies in women with reproductive failure or major abruptio placentae.

The so-called antiphospholipid syndrome may be responsible for repeated spontaneous abortion and fetal loss. We examined the plasma of 61 women with either reproductive failure or abruptio placentae for the presence of lupus anticoagulant and anticardiolipin antibodies in an attempt to assess the prevalence of this condition. No patient had haematological abnormalities consistent with the presence of lupus anticoagulant. However, 6 women had anticardiolipin antibodies with normal coagulation tests. The clinical profile together with this laboratory finding allows us to diagnose the antiphospholipid syndrome in these patients. Our incidence is considerably lower than that reported in many other studies but does suggest a place for screening for this condition in patients with recurrent complications of pregnancy.

Abortion, Habitual↗
PubMed1992

Blood usage in elective surgery--a 3-month audit at Groote Schuur Hospital, Cape Town.

Unnecessary crossmatching of blood is expensive and can result in unwarranted transfusion with needles exposure of patients to the risks of transfusion therapy. Since the extent of unnecessary crossmatching and transfusion at Groote Schuur Hospital, Cape Town had not previously been considered in detail, blood usage in elective surgery was studied over a period of 3 months in 1990 to determine adherence to the Maximum Surgical Blood Ordering Schedule (MSBOS), crossmatch transfusion ratios (CTRs) and transfusion appropriateness. Just over half of blood bank requests were equal to or less than the MSBOS. The overall CTR in elective surgery for this period was found to be 1,7, which, not unexpectedly, is higher than that for the whole of Groote Schuur Hospital (1,4). However, it ranged from 1,4 in cardiac surgery to 4,7 for neurosurgery. Twenty-nine per cent of postoperative transfusions were considered to have been excessive. Transfusion therapy in the peri-operative period is discussed and possible changes in strategy are suggested.

Blood Component Transfusion↗
PubMed1992

Method for the safe and rapid pretransfusion warming of stored blood: an in vitro and in vivo evaluation of a radiofrequency (RF) instrument.

Inadvertent hypothermia due to massive infusion of stored blood can be prevented by pretransfusion warming. One approach is the heating of individual packs by means of electromagnetic conduction, which is a method safely used over the last 25 years. The prototype instrument, which has now been re-engineered, can effectively raise the temperature of a unit of blood to approximately 33 degrees C in less than 3 minutes. Using this new model, we found, in vitro, a modest increase in free plasma haemoglobin, but this was not accompanied by any change in potassium or lactic dehydrogenase levels and the mean red cell fragility was unaltered. In vivo, the survival of autologous red cells that had been stored for 33 days and then infused as a concentrate, having a mean haematocrit of 0.60, was measured at 24 hours and 21 days. Each donor acted as his own control. In paired studies, pretransfusion radiofrequency heating was shown to have no deleterious effect when compared to measurements using the unwarmed blood pack. It is concluded that this method can be recommended as safe.

Adult↗
PubMed1992

Plasmacyte-reticulum cell satellitism in multiple myeloma associated with amyloidosis.

A novel morphological feature is described in a patient with myeloma and associated amyloidosis: characteristic clustering (satellitism) of neoplastic plasma cells around macrophages in bone marrow aspirates. Although described in myeloma cell culture, as far as is known, this is the first description of this phenomenon in a patient. This unique association may partly explain the origin of amyloid deposition in tissues and organs.

Aged↗
PubMed1991

Hepatitis C virus antibodies in patients with liver disease. The western Cape experience.

Hepatitis C virus (HCV) is a recently characterised non-A, non-B hepatitis (NANBH) agent, which appears to be important in both parenteral and sporadic NANBH. HCV infection has been associated with the development of chronic liver disease, cirrhosis and hepatoma. Groups of patients in the western Cape with chronic liver disease and hepatoma were screened for antibodies to HCV and the results were confirmed by standard neutralisation tests. Three of 19 patients with cirrhosis secondary to alcohol abuse or classic auto-immune chronic active hepatitis were considered to have antibodies to HCV at initial screening. All of these were false-positive results. Five of 20 patients with presumptive chronic NANBH were considered possibly to have antibodies to HCV. Only 1 patient with post-transfusional NANBH was confirmed to have specific HCV antibodies. Two of 30 patients with hepatoma had specific anti-HCV antibodies in contrast to 11 others with serum HBsAg positivity. One hundred blood transfusion donors and 25 antenatal patients were tested concurrently and shown to be negative for anti-HCV. Specific antibodies to HCV were present in very few patients with cirrhosis, presumptive NANBH and hepatoma tested in this local survey. False-positive reactions appeared to occur at a higher rate than true-positive results.

Adolescent↗
PubMed1991

High prevalence of hepatitis C virus antibodies in a local haemophiliac population.

Non-A, non-B hepatitis is common among individuals with clotting factor deficiencies who have had multiple exposures to replacement concentrate. Newly introduced screening tests for hepatitis C virus antibody make it possible to determine the prevalence of this entity in defined populations. In 68 haemophiliac patients attending the Groote Schuur Hospital clinic, 44 were shown to be positive (65%). There was no significant correlation between seropositivity for this agent and severity of the bleeding disorder, age or elevation of the liver enzyme values.

Adolescent↗
PubMed1991

von Willebrand's disease in Zimbabwe. A report on 3 families.

Three families with clinically typical features of von Willebrand's disease are described. One family had features to suggest type II disease. Von Willebrand's disease appears to be rare in Africa, but this may be due both to lack of awareness among clinicians and insufficient laboratory facilities.

Adolescent↗
PubMed1991

Acquired hypoprothrombinaemia and lupus anticoagulant: response to steroid therapy.

An iliac crest bone marrow aspiration in a 24-year-old man was followed by severe haemorrhage into the iliopsoas muscle. A lupus anticoagulant and severe hypoprothrombinaemia, as well as clinical and laboratory pointers to suggest the presence of a systemic lupus erythematosus-like syndrome, were demonstrated. Therapy with prednisone was commenced following recurrent severe epistaxis. His prothrombin time, activated partial thromboplastin time and prothrombin activity improved promptly and his bleeding ceased. The lupus anticoagulant is commonly encountered in the laboratory, but acquired hypoprothrombinaemia is extremely rare. The condition is reviewed and its treatment discussed.

Adult↗
PubMed1991

Primary shunt hyperbilirubinaemia: a variant of the congenital dyserythropoietic anaemias.

A 19 year old Mauritian male presented with episodic nausea, abdominal discomfort and jaundice. Unconjugated hyperbilirubinaemia and erythroid hyperplasia without dyserythropoiesis led to the diagnosis of primary shunt hyperbilirubinaemia. The similarity between congenital dyserythropoietic anaemia and this entity suggests that patients with these lesions can be considered within a single spectrum of disorders, characterized as congenital ineffective erythropoiesis.

Adult↗
PubMed1991

Heparin as the cause of coagulopathy which may complicate grafting of the liver.

Disposal of heparin is accomplished rapidly by the normal liver, but the effects of ischemia, flushing and hypothermia during hepatic transplantation have not been investigated before. The results of the present study showed that neither laparotomy, hypothermia nor insertion of the portosystemic bypass seemed markedly to affect the coagulation profile, but autograft associated with 30 to 45 minutes of warm ischemia resulted in a twofold prolongation of the t1/2 heparin as calculated from sequential measurements of the activated clotting time. Unexpectedly, the storage of livers for four hours in EuroCollins solutions seemed to result in more rapid disappearance of heparin than in animals after laparotomy. After hepatectomy, the clearance of heparin was delayed for two hours but, thereafter, the slope of the disappearance resembled that in sham operated animals. Autograft and allograft of livers in normal pigs that did not receive transfusion were also associated with changes in fibrinolysis and declining levels of fibrinogen together with severe intraoperative bleeding problems and rapid death on the operating table in 30 per cent of the pigs. While administration of heparin alone did not appear to precipitate these changes, use of the drug after dissection, mobilization and storage of the liver may release other tissue factors that activate fibrinolysis.

Animals↗
PubMed1990

Glucose partitioning in the pregnant ewe: effects of undernutrition and exercise.

Maternal whole-body glucose entry rate and uterine and umbilical net uptakes of glucose and oxygen were measured in single-pregnant ewes which were either well-fed throughout, or fed at 0.3-0.4 predicted energy requirement for 7-21 d during late pregnancy. All ewes were studied while standing at rest and then while walking on a treadmill at 0.7 m/s on a 10 degrees slope for 60 min. Underfed ewes suffered significant decreases in live weight and had lower fetal, but not placental, weights at 140-144 d gestation. Undernutrition also caused large decreases in maternal glycaemia and glucose entry rate, which were associated with equally large decreases in uterine and umbilical net uptakes and O2 quotients of glucose, and with a decrease in placental glucose transfer capacity. Exercise caused increases in maternal blood concentration, entry rate and uterine net uptake of glucose, the magnitudes of which were not significantly affected by plane of nutrition. Umbilical glucose uptake and placental glucose transfer capacity increased during exercise in underfed but not fed ewes. The fractional distribution of maternal glucose to the pregnant uterus, and of uterine glucose uptake to the fetus, were unaltered by undernutrition; during exercise, a disproportionately small fraction of the increased maternal glucose supply went to the uterus. The results confirm that the ovine conceptus responds to nutritional reduction in maternal glucose availability in a manner similar to non-uterine maternal tissues. Major reductions in glucose supply appear to override putative glucose-sparing mechanisms which may operate to favour the conceptus in better-nourished animals.

Animals↗
PubMed1990

Effects of maternal undernutrition and exercise on glucose kinetics in fetal sheep.

Fetal glucose kinetics were measured using a combination of isotope-dilution and Fick-principle methodology in single-pregnant ewes which were either well-fed throughout, or fed at 0.3-0.4 predicted energy requirement for 7-21 d during late pregnancy. All ewes were studied while standing at rest and then while walking on a treadmill at 0.7 m/s on a 10 degree slope for 60 min. Underfed ewes suffered major decreases in fetal total disposal rate, fetal-placental transfer and umbilical net uptake of glucose, each of which were significantly related to declines in maternal and fetal blood glucose concentrations respectively. In well-fed ewes, fetal endogenous glucose production was negligible, as indicated by the similarity between fetal utilization rate (total glucose disposal rate minus placental uptake of fetal glucose) and umbilical net uptake of glucose, and by nearly identical fetal and maternal arterial blood specific radioactivities of maternally infused D-[2-3H]glucose. By contrast, in underfed ewes, fetal utilization rate greatly exceeded umbilical net uptake of glucose, and the fetal:maternal [3H]glucose specific activity ratio declined significantly, suggesting induction of a substantial rate of fetal endogenous glucogenesis. Exercise caused increases in fetal total glucose disposal rate and glycaemia in fed and underfed ewes. In underfed ewes only, this was accompanied by increased placental uptake of fetal glucose and umbilical net glucose uptake, unchanged fetal glucose utilization and decreased fetal endogenous glucose production. It is concluded that fetal gluconeogenesis makes a major contribution to fetal glucose requirements in undernourished ewes. Increased maternal supply of fetal glucose during exercise substitutes for rather than adds to fetal endogenous glucogenesis.

Animals↗
PubMed1989

Immunophenotyping in the diagnosis and classification of acute leukaemia.

Ninety-four consecutive patients with acute leukaemia were analysed using cytochemical stains and, in selected individuals, a panel of monoclonal antibodies combined with measurement of the enzyme terminal deoxynucleotidyl transferase. These results were correlated with the French-American-British morphological classification. Acute non-lymphoblastic leukaemia was diagnosed in 55 individuals on the basis of morphology and cytochemical criteria; 6 of this group were further studied with antibodies directed against specific myelomonocytic antigens, but no further clinically useful information was obtained. Blasts from 36 patients did not stain with either Sudan black or myeloperoxidase. These individuals were considered to have acute lymphoblastic leukaemia (ALL) and were further assessed with monoclonal antibodies directed against epitopes expressed on cells of lymphoid lineage; 10 were classified as arising from T precursors; 23 were of B lineage, of which 13 marked as common, 6 as null, 1 as pre-B, 2 as B-ALL and 1 to have a pattern characteristic of lymphoblastic lymphoma. Two cases could not be classified and 1 was found to have megakaryoblastic features. In a further 3 patients who had undergone lymphoblastic transformation as a terminal event in the course of chronic granulocytic leukaemia, 2 were immunophenotypically common and 1 was marked as a null cell. This study confirms the value of monoclonal antibodies for accurately assigning lineage to the acute leukaemias and particularly in those situations where conventional morphological criteria and cytochemical markers are inconclusive.

Adult↗