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Biomedical subjects

H Fong

Publications and source records attributed to H Fong.

14 recordsLinked to original sources
PubMed1989

Red cell ferritin and iron overload in heterozygous beta-thalassemia.

Red cell ferritin was evaluated in 101 individuals with heterozygous beta-thalassemia to determine its clinical utility as an index for iron deficiency or overload in these subjects. The mean red cell ferritin for the total population was elevated threefold and showed a significant correlation with transferrin saturation, plasma ferritin, and HbA2 levels. Five of six subjects with reduced red cell ferritin had associated iron deficiency; a further five had iron deficiency and normal red cell ferritin. Normal red cell ferritin occurred in 51 subjects, and 44 had increased values. In the elevated red cell ferritin group, 21 individuals had associated normal plasma ferritin, and 23 had increased plasma ferritin. Only in the latter group was red cell ferritin significantly correlated with transferrin saturation and plasma ferritin. Ten individuals had a red cell ferritin greater than or equal to 150 attogram/cell, and liver biopsy performed in four showed grades II to IV iron overload. A clinical feature of subjects with both increased red cell and plasma ferritin levels was a high incidence of inappropriate iron administration. These findings suggest that red cell ferritin, particularly when combined with plasma ferritin, is a useful parameter for determining potential iron overload in individuals with heterozygous beta-thalassemia.

Adolescent↗
PubMed1988

Transplantation in Manitoba.

1. Renal transplantation can be performed at small regional centers as successfully as at large centers. 2. Immunosuppression should be individualized for the patient thereby avoiding the use of costly and often clinically complicated immunosuppressive regimens. 3. Small centers need to participate in large regional pools in order to give highly presensitized patients a reasonable chance of successful transplantation. 4. Long-term patient compliance is a major problem and requires careful surveillance of patients' adherence to their prescribed therapy. Frequent follow-up also allows for the detection of late rejection episodes which can often be reversed.

Graft Survival↗
PubMed1986

Low-dose intra-arterial streptokinase infusion therapy of peripheral arterial occlusions and occluded vein grafts.

To study the effectiveness of low-dose thrombolytic therapy the authors report their experience with local, low-dose, intra-arterial streptokinase infused at a rate of 5000 units/h in four patients with occluded vein grafts and eight with peripheral arterial occlusions presenting with limb-threatening ischemia. The patients had had symptoms for 4 hours to 6 weeks. The streptokinase infusion successfully declotted two occluded vein grafts and restored distal blood flow in five patients with peripheral arterial occlusion. Complications resulting in early withdrawal of thrombolytic therapy included surgical wound hematomas in two patients. Two patients had severe bleeding at the arterial puncture site leading to the death of one of them. Treatment after cessation of thrombolytic therapy included femoropopliteal bypass in three patients, percutaneous transluminal balloon dilatation of a stenotic popliteal artery in one patient and thromboembolectomy in three patients. Two patients required below-knee amputation because of irreversible ischemia. The authors conclude that in carefully selected patients, intra-arterial infusion of streptokinase locally in low dosage is an important adjunct in the treatment of limb-threatening ischemia caused by occluded vein grafts and acute arterial thrombosis. They warn that selective thrombolytic therapy with streptokinase must be used with caution since it may be associated with serious complications.

Aged↗
PubMed1984

Red cell ferritin content: a re-evaluation of indices for iron deficiency in the anaemia of rheumatoid arthritis.

In iron deficiency anaemia basic red cell content of ferritin is appreciably reduced. This variable was determined in 62 patients with rheumatoid arthritis to evaluate conventional laboratory indices for iron deficiency in the anaemia of rheumatoid arthritis. For 23 patients with rheumatoid arthritis and normocytic anaemia irrespective of plasma ferritin concentration, red cell ferritin content did not differ significantly from that for non-anaemic patients with rheumatoid arthritis. For 27 patients with rheumatoid arthritis and microcytic anaemia, the mean red cell ferritin content for patients with a plasma ferritin concentration in the 13-110 micrograms/l range was appreciably reduced. It was indistinguishable from that for patients with rheumatoid arthritis and classical iron deficiency anaemia, indicated by plasma ferritin concentrations of less than 12 micrograms/l. In contrast, the mean red cell ferritin content for patients with rheumatoid arthritis, microcytic anaemia, and plasma ferritin concentrations above 110 micrograms/l did not differ from that for patients with rheumatoid arthritis and normocytic anaemia. Oral treatment with iron in patients with rheumatoid arthritis, microcytic anaemia, and appreciably reduced red cell ferritin concentrations was accompanied by significant increases in haemoglobin concentration (p less than 0.01), mean corpuscular volume (p less than 0.01), and red cell ferritin contents (p less than 0.05). This treatment, however, did not produce any appreciable change in haemoglobin concentration in patients with rheumatoid arthritis, normocytic anaemia, and normal red cell ferritin contents. These findings suggest that the indices for iron deficiency in patients with rheumatoid arthritis and anaemia should include peripheral blood microcytosis together with a plasma ferritin concentration of less than 110 micrograms/l.

Adolescent↗
PubMed1984

Red cell basic ferritin content of patients with megaloblastic anaemia due to vitamin B12 or folate deficiency.

The basic ferritin content of red cells was measured in patients with untreated megaloblastic anaemia. The red cell ferritin of 10 patients with anaemia and vitamin B12 deficiency (mean 579, range 68-2616 attogram (ag)/cell); and of 8 patients with folate deficiency (mean 792, range 141-2373 ag/cell) were significantly elevated (P less than 0.001) compared with normal subjects (mean 10.7, range 4-47 ag/cell) and showed a significant correlation with pre-treatment levels of plasma ferritin and less so with percent transferrin saturation. Following vitamin replacement elevated red cell ferritin levels decreased during the period of reticulocytosis and was normal in 9 patients evaluated after 6 months. The magnitude of increase in red cell basic ferritin levels observed in untreated megaloblastic anaemia is comparable to that of subjects with idiopathic haemochromatosis and suggests that interpretation of this index for iron overload should take into consideration concomitant body folate or vitamin B12 status.

Adult↗
PubMed1984

Basic ferritin content of red cells of patients with anemia and polycythemia vera.

Basic ferritin content of red cells has been evaluated with a simplified assay in subjects with various erythroid disorders. In 39 patients with iron deficiency anemia, red cell ferritin was significantly reduced compared with that of normal individuals. Thirty percent of these patients had low normal red cell ferritin content and the MCV for this group was significantly higher than that of patients with reduced red cell ferritin. The mean red cell ferritin of 30 subjects with the anemia of chronic disease was significantly reduced and patients in this group with normal red cell ferritin had higher plasma ferritin levels. In 14 patients with polycythemia vera, the mean red cell ferritin was significantly reduced and showed a positive correlation with the hemoglobin level and percent transferrin saturation. The red cell ferritin content of 9 individuals with acquired immune hemolytic anemia and 10 with acquired sideroblastic anemia was significantly elevated and, in subjects with immune hemolysis, showed a positive correlation with the reticulocyte count. These findings suggest a lack of discriminatory function for red cell ferritin in iron deficiency anemia and anemia of chronic disease. Evaluation of this parameter in the individual patient should take into account the presence of reticulocytosis.

Anemia↗
PubMed1983

Erythrocyte ferritin content in idiopathic haemochromatosis and alcoholic liver disease with iron overload.

The erythrocyte ferritin content was measured in patients with either idiopathic haemochromatosis or alcoholic liver disease and iron overload to define its value as a marker for an excess of tissue iron. The mean erythrocyte ferritin content in patients with untreated idiopathic haemochromatosis was increased 60-fold and fell with phlebotomy. After phlebotomy many patients had an increased red cell ferritin content despite normal serum ferritin concentrations. That this reflected persistent iron overload with inadequate phlebotomy was suggested by the higher serum iron concentrations, percentage transferrin saturation, and urinary excretion of iron after administration of desferrioxamine, together with a lower annual iron loss by phlebotomy in this group compared with patients with treated disease and normal red cell ferritin content. The mean erythrocyte ferritin content in patients with alcoholic liver disease and iron overload was increased only sevenfold, and the ratio of erythrocyte to serum ferritin clearly discriminated these patients from those with idiopathic haemochromatosis. The determination of erythrocyte ferritin content is a useful non-invasive test for diagnosing idiopathic haemochromatosis, monitoring the effect of phlebotomy in this disorder, and distinguishing patients with this disorder from those with alcoholic liver disease with iron overload.

Adult↗
PubMed1980

Hemodynamic assessment of the aortoiliac segment: a prospective study.

A test for assessing stenosis in the aortoiliac segment is described in which femoral pressure is measured directly by continuous monitoring and an intra-arterial injection of papaverine is used to augment blood flow. This test has been described previously but is not widely used. A prospective study of this test was carried out on 64 patients and the results were compared with those obtained by aortography. The test helped to determine whether an operation on the aortoiliac segment was indicated. Clinical results were assessed. Thirty-two of the 64 patients were found to have significant inflow disease (more than 50% stenosis). They underwent aortic reconstruction with total relief or improvement of symptoms in all cases. Aortography demonstrated an essentially normal aortoiliac segment in 3 of the 32 patients and 16 had only irregular segments with no definite stenosis. The authors conclude that any patient presenting with sufficient indication to warrant reconstructive surgery who has a normal or equivocal angiogram should undergo the papaverine pressure test.

Aorta, Abdominal↗
PubMed1979

A simple radiometric assay for methotrexate and other folate antagonists.

A rapid radiometric assay for the folate antagonist MTX, based on the inhibition of chicken liver dihydrofolate reductase activity, has been developed. In the system the inhibition by MTX of the reduction of tritiated FH2 is standardized and used to quantitate this antagonist in plasma of subjects receiving high-dose MTX therapy. The assay permits the detection of plasma MTX levels to 5 X 10(-9)M with a coefficient of variation of 15%. The predominating circulating folate, 5 methyltetrahydrofolate, or the rescue agent leucovorin (5 formyltetrahydrofolate) do not significantly interfere with the assay at concentrations attainable with current rescue programs. Analyses of multiple plasma samples with the present assay show close agreement with the competitive protein-binding assay.

Animals↗
PubMedDate not supplied

Gauging pesticide exposure of handlers (mixer/loaders/applicators) and harvesters in California agriculture.

Agricultural workers acquire pesticide exposures as a function of the properties of the product, crop, and work task. Mixer/Loaders and Applicators have greater exposure potential than other workers since concentrated formulations are handled during preparation and application of spray mixes. Exposures can be estimated using passive dosimetry and biological monitoring. Measured exposures are invariably less than estimates derived from surrogate data due to a series of conservative "worst case" assumptions and exposure estimates derived from small portions of the work day. Data have also been collected to estimate the exposure potentials of harvesters. We are establishing a set of empirical transfer factors (cm2/h) that can be used to estimate daily harvester exposure (transfer factor x dislodgeable foliar residue x hours). These estimates are important to current efforts to establish exposure-based reentry intervals to protect against acute and chronic toxicity.

Agriculture↗
PubMedDate not supplied

Popliteal artery entrapment syndrome with distal embolization. A report of two cases.

The popliteal vascular entrapment syndrome has been recognized as a cause of arterial occlusion in young males for several decades. The ischemia is usually caused by thrombosis of the popliteal artery due to intimal trauma or aneurysm formation. Distal embolization to the tibial arteries and to the foot arch and digital vessels is common but is not emphasized in the literature. This distal embolization may precipitate severe ischemia which may preclude reconstruction or compromise the results of repair of the popliteal lesion. Early repair of the muscle anomaly is advocated even in the asymptomatic limb. Two patients with bilateral popliteal artery entrapment causing unilateral popliteal occlusion with distal embolization are reported.

Adolescent↗