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Biomedical subjects

R D Lange

Publications and source records attributed to R D Lange.

At least 37 records · Page 2Linked to original sources
PubMed1984

A study of a Caucasian family with variant von Willebrand's disease in association with vascular telangiectasia and haemoglobinopathy.

A family was identified which carries multi-haematological disorders including Type IIA von Willebrand's disease, vascular telangiectasia, and a haemoglobinopathy (haemoglobin S trait). In the affected individuals, the von Willebrand's disease varies in its expression from an asymptomatic form to a severe form especially in those patients with telangiectasia. Some patients have vascular telangiectasia in the mucous membranes of the mouth and lips. In two patients endoscopy disclosed telangiectasia in the mucous membranes of the gastrointestinal tract. All of the patients who had telangiectasia also had von Willebrand's disease. An incidental finding was the presence of an abnormal haemoglobin (haemoglobin S) in some family members. The pattern of inheritance of the haemoglobinopathy was unrelated to the inheritance pattern of von Willebrand's disease. The presence of haemoglobin S did not interfere with the aggregation of platelets in response to ristocetin.

Adult↗
PubMed1984

Serum erythropoietin titers during prolonged bedrest; relevance to the "anaemia" of space flight.

The overall objective of these studies was to test the hypothesis that the suppression of erythropoiesis, which occurs during both spaceflight and bedrest, was mediated by reduction in circulating levels of erythropoietin. In each of two 7-day studies, groups of subjects were exposed to either horizontal or 6 degrees head-down tilt bedrest and no evidence was obtained to suggest that the erythropoietic effects were dependent on the angle of recumbency. An additional study involved six men who were exposed to horizontal bedrest for 28 days. Serum erythropoietin titers were not significantly depressed in any of the subjects but total red cell volume was decreased. Absolute increases in red cell numbers and reductions in plasma volume both elevate the haematocrit, but our data suggest that the mechanism of erythrosuppression in these two instances may be different.

Adult↗
PubMed1984

Nucleotide and prostaglandin cycling in canine cyclic hematopoiesis.

Bone marrow cells were collected from normal dogs, normal dogs made neutropenic with cyclophosphamide, and 11 dogs affected with cyclic hematopoiesis (CH) on 3 consecutive days of separate 12- to 14-day cycles. The mononuclear marrow cells from both groups of control dogs and from the CH dogs on each of 12-cycle days were cultured for 2.5 hr in serum-free media. The amounts of prostaglandins (PGF2 alpha and PGE) and cyclic GMP (cGMP) measured in the media were found to vary with the cycle in the CH dog. PGF2 alpha was highest as the dogs recovered from the neutropenia and lowest 4 days before the onset of the next neutropenic episode. Cyclic GMP was lowest 4-5 days before the onset of neutropenia, then dramatically increased as the neutropenic period approached. Cyclic GMP was highest when PGF2 alpha was lowest. Normal dogs, made neutropenic with a single dose of cyclophosphamide, had elevations of PGF2 alpha but not PGE or cGMP during the recovery period of active granulopoiesis.

Agranulocytosis↗
PubMed1984

Preparation of purified erythropoietin by high performance liquid chromatography.

Highly purified erythropoietin was not available in quantities needed to carry out planned investigations and, therefore, the use of high performance liquid chromatography was explored. This technique permits the separation of proteins with high efficiency and resolution. Three types of chromatography were used. Size exclusion or gel permeation, reversed phase, and ion exchange columns were utilized with different solvent systems. The chromatographic fractions were assayed either by an exhypoxic polycythemic mouse assay or by the fetal liver cell assay. In addition, selected fractions were tested for their capability to stimulate CFU-E and BFU-E colony formation in methyl cellulose. The results of the techniques of size exclusion and ion exchange chromatography were found to be rapid and reproducible. Although reversed phase chromatography gave excellent resolution, the results were somewhat variable. Using different chromatographic combinations, erythropoietin with a specific bioactivity in the range of 50,000 u/mg protein was isolated. Although the erythropoietin gene has now been cloned and the hormone purified by utilizing monoclonal antibodies, high performance liquid chromatography may be useful in the removal of unwanted contaminants, as a tool in chemical characterization, and as a possible method for the hormone's identification and measurement in clinical laboratories.

Anemia, Aplastic↗
PubMed1983

Serum erythropoietin changes in cats with feline leukemia virus-induced erythroid aplasia.

Erythropoietin concentrations were increased significantly (p less than 0.025) in nine cats with natural feline leukemia virus infection and associated erythroid aplasia compared to six clinically normal cats. Adult cats experimentally inoculated with the Kawakami-Theilen isolate of feline leukemia virus developed a progressive simultaneous increase in erythropoietin activity and decrease in packed cell volume. These findings indicate that erythroid aplasia associated with feline leukemia virus infection is not caused by a failure in erythropoietin production.

Anemia, Aplastic↗
PubMed1983

Cyclic hematopoiesis: human cyclic neutropenia.

Human cyclic neutropenia is a relatively rare disorder of unknown etiology. Study of patients and animals with the disorder has led to important information regarding the differentiation of blood cells and control mechanisms of hematopoietic regulation. It has a world-wide distribution, occurs in both sexes, and, in about one-fourth of the patients, a family history has been obtained. While usually benign, deaths from overwhelming infections occur. In addition to cycling of neutrophils, in the majority of cases the monocytes cycle and in about one-fifth of the cases eosinophils are elevated. In a small number of patients, cycling of platelets and reticulocytes occurs. Cycles of colony stimulating factor are present. Cycles of bone marrow cells are easily demonstrable. The recent transfer of human cyclic neutropenia following allogenic bone marrow grafting confirms the hypothesis that the disorder is of bone marrow origin. The following subjects are covered in this review article: A. Definition, history, and incidence; B. Etiology, geographic distribution, mode of transmission; C. Symptoms, physical signs, diagnosis, clinical course; D. Clinical laboratory studies; E. Experimental studies; F. Prognosis; G. Treatment. It is felt that human cyclic neutropenia represents a heterogeneous group of disorders and that much remains to be learned about its cause(s).

Adolescent↗
PubMed1983

Cyclic Hematopoiesis: animal models.

The four existing animal models of cyclic hematopoiesis are briefly described. The unusual erythropoietin (Ep) responses of the W/Wv mouse, the Sl/Sld mouse, and cyclic hematopoietic dog are reviewed. The facts reviewed indicate that the bone marrow itself is capable of influencing regulatory events of hematopoiesis.

Anemia↗
PubMed1982

Production of presumptive humoral haematopoietic regulators in canine cyclic haematopoiesis.

Conditioned media (CM) were prepared according to previously published techniques from the bone marrow of dogs with cyclic haematopoiesis (CH). CM prepared from day 9 marrows inhibited mouse bone marrow CFU-s proliferation rate while CM from day 10 marrows were stimulatory and also contained an erythroid stimulating factor which appeared to be erythropoietin. In addition a highly significant trend from CM containing CFU-s inhibitory materials to media with CFU-s stimulatory activity was observed through cycles day 1 to 8. These studies further support the concept that CH is due to a defect in factors controlling stem cell proliferation and suggest that a major event occurs in CH dog marrow on days 9 and/or 10 of the cycle.

Animals↗
PubMed1982

Canine cyclic hematopoiesis: blood gas and 2,3-diphosphoglyceric acid studies.

Cyclic hematopoiesis in gray Collies was first described in 1967. These dogs are anemic in comparison with the healthy littermates, and their erythropoiesis is abnormal. Although the basic disorder appears to be an as yet unidentified abnormality of hematopoietic progenitor cells, an inherent difference in responses to blood gas control mechanisms remains as a possible cause. In a study of these mechanisms in dogs with cyclic hematopoiesis, the P50 and 2,3-diphosphoglyceric acid concentrations were increased. Differences in pH, PCO2, PO2, and oxygen saturation were not observed.

2,3-Diphosphoglycerate↗
PubMed1982

Cyclic hematopoiesis: etiological concepts. Clinical research update.

The cellular elements of the blood are normally maintained in a remarkable steady state. However, in human patients with cyclic neutropenia and in a putative animal model--canine cyclic hematopoiesis--the formed elements oscillate with constant regularity. The clocklike precision of the cycles implies a strong regulatory control failure. Since an understanding of the pathogenesis of these events could enhance our perception of normal and abnormal regulatory mechanisms, we have undertaken briefly to review current concepts regarding the possible etiologies of cyclic hematopoiesis.

Agranulocytosis↗
PubMed1981

Cyclic neutropenia. A tale of two brothers and their family.

A family history encompassing four generations is presented. Definite cyclic neutropenia has been noted in two generations. In one member, the symptoms abated as she grew older. One 12-year-old member died of clostridial septicemia secondary to gangrene of the terminal ileum. At autopsy he was found to have amyloidosis. A trial of lithium carbonate therapy was carried out in a 7-year-old male but a positive hematologic response was not obtained.

Adolescent↗
PubMed1981

Activated factor IX complex in treatment of surgical cases of hemophilia A with inhibitors.

Three patients with severe hemophilia A with inhibitors to factor VIII were treated with activated factor IX complex. Bleeding was controlled adequately during surgical procedures involving each of the three. Partial thromboplastin times showed a variable shortening and prothrombin times were significantly shortened to values less than normal. Hemostasis was substantiated by the use of epsilon aminocaproic acid. Neither anamnestic responses nor thrombotic complications were observed. A transient hypertension developed in two patients shortly after infusion with the activated factor IX complex.

Adult↗
PubMed1981

Cyclic neutropenia. Review of clinical manifestations and management.

Human cyclic neutropenia probably represents a rare group of heterogeneous disorders. The disorder most frequently starts in infancy or childhood. During the neutropenic episodes, the most common symptoms are fever and oral ulceration. However, dental and skin manifestations are frequent and require special attention. While the disease is usually benign and the symptoms may ameliorate as the patient grows older, 15 deaths related to neutropenia have been recorded. While many modalities of treatment have been suggested, none have proved to be universally efficacious. Study of cyclic neutropenia may provide insight into the normal control of granulopoiesis and into the genesis of biological rhythms.

Adrenal Cortex Hormones↗
PubMed1980

Regulation of erythropoiesis in diabetes mellitus.

The regulation of erythropoiesis in 40 subjects with diabetes mellitus was investigated to test the hypothesis that increased blood concentrations of glycosylated hemoglobin would produce a reduced p50 and a compensatory increase in erythropoietin. Little evidence to support this hypothesis was observed. However, diabetes did produce complex changes in hemoglobin-oxygen releasing capacity which were compensated for in the expected way, i.e. oxygen releasing capacity showed an inverse correlation with erythropoietin. We conclude that the effects of diabetes on erythropoiesis are minor and probably have no pathological significance in most patients suffering from this disease.

Adolescent↗
PubMed1980

The ultrastructural immunocytochemical demonstration of erythropoietin receptors on developing erythrocytic cells of fetal mouse liver.

In spite of the severe restrictions imposed by the lack of high purity erythropoietin (Ep) and Ep specific antiserum wer have attempted to demonstrate presumptive Ep binding sites on the surface of developmental forms of erythrocytic cells of the mouse fetal liver using ultrastructural immunocytochemical methodology. Cells were exposed to exogenous Ep of differing potencies and concentrations and subsequently incubated in an Ep antiserum. The Ep-Ep-antiserum complex was then visualized with a gold-labeled IgG reagent. Limited surface labeling was noted on the developing erythrocytic cells and the evaluation of the mean surface labeling densities of the erythrocytic cell series indicated that the extent of labeling was related to the stage of maturation. Early polychromatophilic erythroblasts proved to be the most heavily labeled of the erythrocytic cells followed by the basophilic erythroblast, proerythroblast and late polychromatophilic erythroblasts respectively; normoblasts, reticulocytes and erythrocytes exhibited, at most, only minimal labeling. In addition, we have been able to demonstrate several primitive cells in the fetal liver which exhibited extensive surface labeling when compared with the developing erythrocytic cells. These cells may represent the erythroid precursors of the fetal liver.

Animals↗