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Biomedical subjects

J T Prchal

Publications and source records attributed to J T Prchal.

126 records · Page 7Linked to original sources
PubMed1981

The effect of diabetes mellitus and diabetic therapy on cataract formation.

A study of diabetic and nondiabetic subjects was performed to evaluate the possible association of diabetes mellitus with cataract formation. Parameters investigated included cataract incidence and type model of diabetic therapy, degree of diabetic control, duration of glucose-6-phosphate dehydrogenase (G-6-PD) activity. Diabetes mellitus was found to be correlated with posterior subcapsular cataract formation, as was duration of diabetic disease. Race, degree of metabolic control, and age of onset of disease did not appear to be correlated with cataract formation. Oral hypoglycemic agent therapy was significantly associated with posterior subcapsular cataract formation. The African variant of G-6-PD deficiency appeared to protect against cataract formation in diabetic patients. The most important overall factor in cataractogenesis proved to be age. Posterior subcapsular cataracts were associated with corticosteroid therapy, presence of diabetes mellitus, and oral hypoglycemic agent therapy.

Adult↗
PubMed1981

Cataracts and riboflavin deficiency.

Lenticular reduced glutathione, diminished in all forms fo human cataract, requires flavin adenine dinucleotide as a coenzyme for glutathione reductase. Deficiency of riboflavin, a precursor of flavin adenine dinucleotide, has been believed by some to be associated with cataract formation. We evaluated the riboflavin nutritional status of healthy young adults, presenile and senile cataract patients, and young and older patients with clear lenses. We found no evidence of an association between riboflavin deficiency and early cataract formation, either idiopathic or secondary. Older cataract patients had more riboflavin deficiency. An absence of riboflavin deficiency was found in our older patients with clear lenses. The degree of riboflavin deficiency encountered in the general population does not appear to be cataractogenic.

Adult↗
PubMed1980

Presenile cataract formation and decreased activity of galactosemic enzymes.

One hundred forty-seven patients, 144 with advanced cataract formation, had determinations of erythrocyte galactokinase and galactose-1-phosphate uridyl transferase performed. Significant reduction (more than 2 SDs) of one of these enzymes was found in 47.4% of patients 50 years old or less with presenile "idiopathic" bilateral cataracts, 7.1% of other patients with cataracts aged 50 years or less, and 3.8% of patients with cataracts aged 51 years or more. The differences between the group with presenile idiopathic cataracts and the other groups were statistically highly significant (P less than .001). Patients with reduced activity of galactokinase or galactose-1-phosphate uridyl transferase (presumed heterozygotes) compose about 1% of the general population, appear to be more susceptible to idiopathic presenile cataract formation, and may be more prone to secondary cataract formation after a variety of lenticular insults. Dietary restriction of milk and milk products may prevent or delay cataract formation in these individuals.

Adult↗
PubMed1980

Effect of corticosteroids on cataract formation.

While the cataractogenic effects of corticosteroids are beyond dispute, disagreement exists concerning effects of total dose, intensity of dose, and duration of administration on cataract formation. We studied 106 adult male patients matched for age, race, and socioeconomic status. We compared posterior subcapsular (PSC) cataract formation among those with (39) and without (67) a history of systemic corticosteroid therapy. Difference in incidence of PSC opacities among patients with and without a history of corticosteroid therapy was statistically significant. However, no statistically significant correlation was found between PSC opacities and total steroid dose, weekly dose (intensity), duration of dose, or age of patient. Our findings agree with some recent literature that suggests the most important factor in steroid-induced PSC cataract formation may be variability in individual susceptibility to side effects of corticosteroids. We suggest abandoning the concept of a "safe" dose.

Adrenal Cortex Hormones↗
PubMed1980

Urinary acidification in a patient with glucose-6-phosphate dehydrogenase deficiency. A reevaluation of the role of the hexose monophosphate shunt in renal acid secretion.

The relationship between renal metabolism and urinary acidification is poorly understood. During the past decade evidence has accrued to suggest that the hexose monophosphate (HMP) shunt might serve in the process of urinary acidification by providing reducing equivalents for a redox-coupled membrane-bound proton pump that could transport protons into the tubular lumen. The major support for this hypothesis has come from the finding that HMP shunt activity increases with acute and chronic metabolic acidosis. In the present study, we examine the urinary acidification capacity of a young man with severe erythrocyte glucose-6-phosphate dehydrogenase (G-6-PD) deficiency and with unmeasurable G-6-PD activity in renal cortical tissue. We found that despite unmeasurable G-6-PD activity in renal tissue, the patient was capable of generating a maximally acid urine and increasing total acid secretion. Our findings suggest that the HMP shunt may not be necessary for the urinary acidification process.

Adolescent↗
PubMed1980

Presence of J chain in human lymphoid cells.

The presence of J chain in normal lymphoid cells (examined at various stages of differentiation) and in lymphocytes and plasma cells from patients with malignant haematologie disorders was determined by the immunofluorescence technique. J chain was not detectable in the cytoplasm or on the surface of either pre-B or B cells, but was present in a few peripheral blood lymphocytes that contained intracellular immunoglobulins of various classes. After pokeweed mitogen stimulation, intracellular synthesis of J chain and immunoglobulins appeared simultaneoulsy and was most pronounced during early days of culture. These data indicate that J chain is not expressed during the earliest stages (pre-B and B cells) of differentiation of lymphoid cells and that the synthesis of J chain is closely linked to the production of immunoglobulin chains, irrespective of the class. Examination of lymphoid cells from bone marrow and peripheral blood of patients with various lymphoproliferative diseases (secretory and non-secretory multiple myeloma or Waldenström's macroglobulinaemia, H- or L-chain diseases, chronic lymphocytic leukaemia, plasma cell leukaemia, and angioimmunoblastic lymphoma) revealed that J chain was present in various proportions of the cells that contained monomeric (IgG, IgD or IgA) or polymeric (IgA or IgM) immunoglobulins, as well as in cells from patients with H- or L-chain diseases. No correlation was apparent between the presence of J chain in lymphoid cells and their ability to secrete their product. Preliminary data indicate that J chain may participate in the intracellular assembly of immunoglobulins from their component chains.

B-Lymphocytes↗
PubMed1980

Wiskott-Aldrich syndrome: cellular impairments and their implication for carrier detection.

A family in which two male siblings were affected with Wiskott-Aldrich syndrome (WAS) was studied using G-6-PD isoenzymes as an X-linked marker in order to investigate the nature of cellular abnormalities. Isolated peripheral blood cell types from the doubly heterozygous mother of the affected males seemingly failed to express the G-6-PD allele in cis position with the WAS allele while her cultured skin fibroblasts expressed both G-6-PD alleles. Additionally, a histogram analysis of platelet size revealed a single population of abnormally small platelets in the affected propositus, whereas the heterozygous mother had no appreciable small platelet subpopulation. In vitro culture of hemopoietic progenitor cells of the heterozygous mother showed that the majority of progenitor cells did not express the WAS allele. However, a small number of cells expressing the G-6-PD type linked with the WAS allele were detected. The proportion of the latter progenitors was significantly higher among more primitive progenitors (those giving rise to later appearing colonies). This observation suggests that selection against cells expressing the Wiskott-Aldrich defect takes place in the hemopoietic system of the heterozygous female and offers a possible means of carrier detection in some women. Linkage studies in this family revealed one example of probable recombination between the loci for WAS and G-6-PD among three informative subjects, suggesting that these two loci may not be closely linked on the X-chromosome.

Blood Cells↗
PubMed1979

Multiple myeloma masquerading as chromophobe adenoma.

A 62-year-old woman presenting with intracranial lesion eroding the sella with compression of optic chiasma was found to have plasmacytoma of the pituitary area. At the time of initial surgery, the patient had no biochemical, immunologic or marrow findings of multiple myeloma. The intracranial tumor was interpreted initially as chromophobe adenoma on light microscopy, but the diagnosis of plasmacytoma was established by electron microscopic examination of the tumor. The case illustrates the usefulness of electron microscopy as a diagnostic tool.

Adenoma, Chromophobe↗
PubMed1979

Splenectomy for hematologic disease.

One hundred and thirty splenectomies were performed at the University Hospital in Birmingham for hematologic disorders during a 12 year period. There were seven deaths of which four were related to sepsis in patients with malignant growths which probably impaired immune competence. Splenectomy was found to be uniformly satisfactory for hereditary hemolytic anemia, for hypersplenism complicating rheumatoid arthritis and for the rare instance of primary hypersplenism. Splenectomy was usually salutary in didopathic thrombocytopenic purpura and in antoimmune hemolytic anemia. When done for diagnosis, splenectomy was definitive in about 50 per cent of the instances. Individual patients with thrombotic thrombocyeosinophilia syndrome benefited. Splenectomy for hypoplastic or aplastic anemia in an actual circulation offered only questionable benefit and is rarely necessary for hyperplenism secondary to portal hypertension.

Adult↗
PubMed1978

Association of presenile cataracts with heterozygosity for galactosaemic states and with riboflavin deficiency.

Red cells and the lens of the eye are non-nucleated cells; moreover, they have metabolic similarities. Cataracts develop in childhood in homozygotes for galactosaemic abnormalities, which can be detected by biochemical measurements in red blood-cells. It has not been determined whether heterozygotes for these defects are at greater risk for cataract development later in life. Similarly, riboflavin deficiecy for which the erythrocyte is a sensitive indicator, has been associated with cataracts in animals. Red-cell studies were carried out in 22 patients, aged under 50, with cataracts. Heterozygosity for galactokinase deficiency was detected in 5 patients, for galactose-uridyl transferase in 2, and evidence of an erythrocytic deficiency of riboflavin in 8. Even when Black subjects were excluded from analysis because of their high incidence of polymorphism for galactokinase, these findings are significantly different from those expected from population surveys and suggest that many patients with presenile cataracts have a biochemical abnormality which can be detected by examination of red blood-cells and which may be corrected by dietary restrictions or supplements.

Adolescent↗
PubMed1977

An in vitro measurement of bleeding time.

An in vitro method of measuring the bleeding time is described. The test, called the machine bleeding time (MBT), is not affected by heparin and detects the same types of hemostatic abnormalities as the template bleeding time. It is sensitive to thrombocytopenia, aspirin administration, and von Willebrand's disease. It is a reproducible test suitable for replicate and serial determinations and permits in vitro evaluation of the addition of drugs.

Aspirin↗
PubMedDate not supplied

Hb Bibba or alpha 2 136(H19)Leu-->Pro beta 2 in a Caucasian family from Alabama.

Several members of a large Caucasian family who presented with a congenital Heinz body hemolytic anemia were found to be carriers of the unstable Hb Bibba or alpha 2 136(H19)Leu-->Pro beta 2. Identification by protein analysis was hampered by the instability of the variant which complicated its isolation from shipped blood samples. Moreover, the detection of the CTG-->CCG mutation at codon 136 of the alpha 2 gene required the substitution of dGTP by dITP during the DNA sequencing process to prevent the occurrence of secondary structures and compressions in the sequencing gel. The first Hb Bibba heterozygote, characterized in 1968 (1), is believed to be a member of this family. The clinical expression of the disease is surprisingly variable.

Alabama↗