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Biomedical subjects

S Hussein

Publications and source records attributed to S Hussein.

At least 73 records · Page 4Linked to original sources
PubMed1987

Platelets in idiopathic thrombocytopenic purpura are increased in size but are of normal density.

To determine whether platelet size and volume are related to one another or to platelet age, subpopulations of platelets from patients with idiopathic thrombocytopenic purpura (ITP) have been produced on the basis of density using Percoll gradients. The density distribution of platelets from patients with ITP and from patients with other forms of thrombocytopenia (thought to be nonimmune in nature) was the same as in normal controls. However, the platelets in each density subpopulation from ITP patients were increased in size. beta-thromboglobulin (beta TG) content of platelets from each patient group and the normals increased with density and tended to be higher in ITP than in normal controls. beta TG concentration per unit platelet volume and its level in plasma were similar in ITP patients and in normal controls. This suggests that the apparently normal density of ITP platelets was not a result of degranulation of large, dense platelets. Thus platelet size and density are independently determined and the increased size of platelets in immune thrombocytopenia may be the result of abnormalities in their production.

Blood Platelets↗
PubMed1987

Dissociation between delayed-type hypersensitivity and resistance to pathogenic mycobacteria demonstrated by T-cell clones.

One Lyt-2+ clone and fourteen T-helper clones (Lyt-1+ L3T4+ Lyt-2-) were isolated from Mycobacterium lepraemurium-infected BALB/c and C57BL/6 mice. All the clones were tested for their ability to transfer delayed-type hypersensitivity adoptively, and six clones were tested for their ability to transfer resistance. It was found that four L3T4+ clones that transferred delayed-type hypersensitivity responses locally and one L3T4+ clone that did not had no effect on resistance. The Lyt-2+ clone transferred increased resistance locally (77% reduction in the numbers of organisms recovered from the infection site) but did not transfer delayed footpad responses.

Animals↗
PubMed1986

Microsurgical approach to the cerebellomedullar region in rat.

A microsurgical study was carried out on 20 randomized rats in order to delineate a safe technique for cerebellobulbar approaches. The procedure takes 20-30 min and can be performed with minimum blood loss if anatomical landmarks, particularly the m. obliquus capitis cranialis, are respected.

Animals↗
PubMed1986

The role of filtration in the provision of leukocyte poor red cells to multitransfused patients.

Five techniques for the preparation of leukocyte poor red cells were investigated to compare their efficiency in preventing febrile transfusion reactions with their cost of production, in order to establish a cost-effective transfusion programme for chronically anemic patients. Leukocyte depletion and preparation costs per unit for the products were:--microaggregate filtered red cells (MF): 25% leucocyte removal at a cost of $A2; buffy coat poor red cells (BCP): 70% at $A2; washed buffy coat poor red cells (WBCP): 88% at $A28; cotton wool filtered red cells (CWF): 93% at $A23; reconstituted frozen red cells (FC): 97% at $A80. The 5 products were transfused into 103 thalassemia patients with a documented history of febrile transfusion reactions. Reaction rates, expressed as a percentage of units transfused over a 12 mth period (MF 7%, BCP 0.3%, WBCP 0.1%, CWF 0.1%, FC 0.2%) correlated well with the degree of leukocyte depletion. The cost of CWF was reduced by a further 10% using the filter in line during the transfusion. Serum from these patients was screened for leukocyte and platelet antibodies using microlymphocytotoxic, granulocyte immunofluorescence and platelet immunofluorescence assays. There was no correlation between the antibodies present and the type of leukocyte poor product required by a patient to prevent a febrile reaction. A progressive regimen of transfusion (BCP to CWF to FC as the patient reacts) has now been adopted, with considerable cost saving.

Blood Platelets↗
PubMed1986

[Modification of intracranial pressure by urapidil following experimental cold lesions in the cat].

The action of the antihypertensive agent Urapidil was investigated in an experimental animal model of vasogenic brain oedema. Animals with normal or raised intracranial pressure received Urapidil as a bolus injection (0.25 mg/kg body weight) followed by a continuous infusion of Urapidil (1 mg/kg body weight). The bolus injection of the drug was followed by a sharp fall in systemic blood pressure, paralleled by a rise in intracranial pressure, resulting in a shortlasting decline of cerebral perfusion pressure. During continuous infusion of Urapidil in both groups with normal or elevated ICP there was a long-lasting significant fall in the systemic blood pressure without any significant alteration of the intracranial pressure.

Animals↗
PubMed1986

Relationship of platelet-associated immunoglobulin G and platelet protein to platelet size and density in normal individuals and patients with thrombocytopenia.

Total platelet-associated immunoglobulin G (PA-IgG) and platelet volume and protein content in normal individuals and in patients with idiopathic thrombocytopenic purpura (ITP) and other thrombocytopenias of presumed nonimmune origin have been measured on platelets separated into subpopulations on the basis of density on continuous polyvinylpyrrolidone (Percoll) gradients. In all subjects PA-IgG per platelet was primarily found in the lightest platelets at levels up to sevenfold greater than in the heavier platelets. PA-IgG level per platelet was raised in light platelets in 29% of patients with thrombocytopenia and in heavy platelets in 60%. In almost half of these instances the PA-IgG level fell to within the normal range when considered in relation to either platelet volume or protein content. PA-IgG levels of patients with untreated ITP did not differ significantly from those with treated ITP or thrombocytopenia of other causes. Mean platelet volume and protein content of the total platelet population of all subjects showed significant linear correlation (P less than 0.01). Thus PA-IgG of both controls and patients with thrombocytopenia of all causes is preferentially located in the lightest platelets, but increases in PA-IgG in immune thrombocytopenias occur more frequently in the heavier platelets. These findings suggest that part of the process of IgG accumulation by platelets is the same in normal individuals as in patients with thrombocytopenia.

Adolescent↗
PubMed1985

[Treatment results in severe craniocerebral trauma with and without dexamethasone therapy].

A retrospective study was performed to determine the effect of dexamethasone-therapy on the outcome of severe head injuries not combined with other serious injuries. Between 1981 and 1983 we treated 53 of 110 patients with an initial dose of 40 mg dexamethasone followed by 16 mg daily for 10 days. There was no statistically significant difference in the outcome and the lethality of the steroid and nonsteroid group. Infections or other complications did not occur more frequent in dexamethasone-therapy.

Adolescent↗
PubMed1983

Platelets, coagulation and fibrinolysis in patients with diabetic retinopathy.

Twenty control subjects, 12 insulin treated and 10 non-insulin treated diabetics were studied. All diabetics had retinopathy documented by fluorescein angiography and fluorophotometry. Factor VIIIR:Ag and plasma fibrinogen concentrations were elevated in both diabetic groups, but more so in the insulin treated patients. Within this latter group the plasma fibrinogen was also correlated with the degree of retinopathy. Platelets separated on linear isosmolar Percoll gradients showed an increase in intraplatelet beta TG content and concentration and a slight increase in volume of the lightest platelets in the insulin treated diabetics. Plasma platelet factor 4 and antithrombin III concentrations were normal and plasma beta TG levels were elevated only in those patients with renal insufficiency. Platelet aggregometry was performed in 18 diabetic subjects and found to be normal. It is concluded that abnormalities of coagulation and platelets in diabetes are determined by metabolic factors rather than the severity of microvascular disease per se.

Adult↗
PubMed1981

Citrate-dependent iron transport system in Escherichia coli K-12.

Induction of the citrate-dependent iron transport system of Escherichia coli K-12 required 0.1 mM citrate and 0.1 micrometer iron in the growth medium. Five--ten-times more iron than citrate was taken up into the cells which suggests that citrate was largely excluded from the transport. Fluorocitrate and phosphocitrate induced the citrate-dependent iron transport system although they supported iron uptake only very poorly. An outer membrane protein (FecA), belonging to the transport system, was induced in fecB mutants which were devoid of citrate-dependent iron transport. The intracellular citrate and iron concentrations were 10--100-times higher than the external concentrations required for induction of the transport system. It is concluded that only exogenous ferric citrate induced the transport system, and that citrate did not have to enter the cytoplasm. The Tn10 transposon, conferring tetracycline resistance, was inserted near the fec gene region which controls the expression of the citrate-dependent iron transport system. The determination of the cotransduction frequencies of Tn10 with the fecA and fecB markers suggested the gene order fecA fecB Tn10.

Anaerobiosis↗
PubMed1981

Functions in outer and inner membranes of Escherichia coli for ferrichrome transport.

Mutants of the fhuA gene of Escherichia coli K-12, which encodes a receptor protein in the outer membrane, took up ferrichrome after exposure to pronase, whereas fhuB mutants remained transport negative. The latter finding supports our previous proposal that fhuB mutants are defective in a function that residues in the cytoplasmic membrane. Cells remained completely viable after treatment with pronase, although they became sensitive to the antibiotic actinomycin.

Biological Transport↗
PubMed1978

Serum ferritin in megaloblastic anaemia.

Serum ferritin concentrations have been estimated in 30 patients with untreated megaloblastic anaemia, 27 with Addisonian pernicious anaemia. A significant difference was found between the mean serum ferritin level of the 27 pernicious anaemia patients (330 microgram/1) and of 22 normal control subjects (164 microgram/1) (P less than 0.05 greater than 0.02). There was an inverse correlation between serum ferritin and Hb concentration in men with pernicious anaemia but not in women. Serum ferritin levels were lower in 10 of 13 patients studied after 24 h of vitamin B12 therapy and in all 13 studied at 48 h after therapy. The fall continued during the haematological response to therapy. It seems likely that serum ferritin reflects reticuloendothelial iron and the high levels in untreated megaloblastic anaemia are due to the shift in iron from Hb to reticuloendothelial stores. The wide variation in serum ferritin at any given Hb level presumably reflects variation in iron stores of the individual patient.

Aged↗
PubMed1978

The role of serum ferritin in the management of idiopathic haemochromatosis.

The value of the serum ferritin assay in the management of idiopathic haemochromatosis has been examined in groups of patients at diagnosis, during venesection therapy, and following completion of therapy. At diagnosis, serum ferritin levels were elevated in all 16 patients studied, including 10 with precirrhotic disease. Venesection resulted in a gradual fall in serum ferritin which commenced shortly after the start of treatment in 5/8 patients. In 3/8 the fall was preceded by a transient rise in ferritin levels. In three patients serum ferritin fell to normal before liver iron stores had been restored to normal. After therapy serum ferritin proved unreliable in detecting early re-accumulation of hepatic iron stores. Serum ferritin does provide valuable information in patients with idiopathic haemochromatosis, particularly at diagnosis and during therapy. A normal value does not exclude iron storage disease.

Adult↗
PubMed1977

Red cell indices and serum ferritin levels in children.

The blood counts of 187 non-anaemic children who attended hospital with minor illnesses and who were between the ages of 12 months and 6 years were studied retrospectively. As many as 76-8% of these children were found to have MCVs below the normal adult range. A prospective study of a further 28 non-anaemic children in the same age group showed that the majority of children with low MCVs have normal haemoglobin A2 and F levels and have serum ferritin levels within the normal adult range. These findings indicate that microcytosis is an intrinsic feature of erythropoiesis in early childhood and that in most instances this feature cannot be attributed to iron deficiency or beta-thalassaemia syndromes.

Anemia, Hypochromic↗
PubMed1977

Recurrent genital candidosis and iron metabolism.

It was thought possible that recurrent genital candidosis, like chronic mucocutaneous candidiasis, might be related to abnormalities in iron metabolism. Haemoglobin, serum iron, and serum ferritin levels of patients with recurrent genital candidosis were compared with those of patients who harboured yeasts but had no history of 'thrush', and with a control group of patients with no evidence of yeasts or history of 'thrush'. The mean haemoglobin level in patients with recurrent genital candidosis was significantly lower than in the control group (P less than 0-05) but it was thought that this difference did not have much practical meaning. There was no significant difference in the serum iron and serum ferritin levels between the three groups.

Candidiasis↗
PubMed1976

Subcutaneous infusion and intramuscular injection of desferrioxamine in patients with transfusional iron overload.

The effects of intramuscular injection and subcutaneous infusion of desferrioxamine (D.F.) on urinary iron excretion were compared in eleven patients with thalassaemia major and one with congenital sideroblastic anaemia who were being maintained on regular blood-transfusions. Total (48-hour) urinary iron excretion ranged from 3-3 to 40-3 mg (mean 16-3 mg) in nine patients who received 750 mg D.F. intramuscularly before transfusion and from 3-9 to 32-3 mg (mean 11-9 mg) in ten patients who received D.F. by the same route after transfusion. In all 9 patients studied before transfusion, continuous subcutaneous infusion of 750 mg D.F. over 24 hours increased iron excretion by 61-5 to 135-8% (mean 101+/-25-4 S.D.%) compared with intramuscular injection of a similar dose. In the 10 patients studied after transfusion, the iron excretion produced by continuous subcutaneous infusion was from 18-9 to 213% (mean 128+/-74-3%) more than that produced by a single intramuscular injection of D.F. When the subcutaneous dose over 24 hours was increased to 1500 mg in six patients, 48-hour iron excretion ranged from 29-2 to 81-2 mg (mean 52-4 mg) and was increased by 80-2--794% (mean 429%) compared with the excretion when 750 mg was given by intramuscular injection. It is concluded that continuous subcutaneous infusion of D.F. produces more iron excretion in patients with iron overload than intramuscular injection. Providing a suitable portable pump can be carried by the patients, continuous subcutaneous infusion of desferrioxamine may prove a valuable means of preventing or treating iron overload in anaemic patients maintained on regular transfusions.

Adolescent↗