Protein micelles of human histocompatibility antigens (HLA-A and HLA-B).
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Centrifugation, Density Gradient↗
Biomedical subjects
A Ma
Publications and source records attributed to A Ma.
Effect of parathyroid hormone on erythropoiesis.
Inhibitors of erythropoiesis have been found in the blood of uremic patients but their nature has not been identified. These patients have excess blood levels of parathyroid hormone (PTH) and it is possible that PTH inhibits erythropoiesis. The present study was undertaken to examine the effect of intact PTH molecules and some of its fragments on human peripheral blood and mouse bone marrow burst-forming units-erythroid (BFU-E), on mouse bone marrow erythroid colony-forming unit (CFU-E), and granulocyte macrophage progenitors (CFU-GM), and evaluate the interaction between PTH and erythropoietin (Ep) on human BFU-E. Intact PTH (1-84 bPTH) in concentrations (7.5-30 U/ml;) comparable to those found in blood of uremic patients produced marked and significant (P less than 0.01) inhibition of BFU-E and mouse marrow GFU-GM, but not of mouse marrow CFU-E. Inactivation of 1-84 bPTH abolished its action on erythropoiesis. Increasing the concentration of Ep in the media from 0.67 to 1.9 U/ml overcame the inhibitory effect of 1-84 bPTH on BFU-E. The N-terminal fragment of PTH (1-34 bPTH) and 53-84 hPTH had no effect on BFU-E. The results demonstrate that (a) either the intact PTH molecule or a C-terminal fragment(s) bigger than 53-84 moiety exerts the inhibitory effect on erythropoiesis, and (b) adequate amounts of Ep can overcome this action of PTH. The data provide one possible pathway for the participation of excess PTH in the genesis of the anemia of uremia.
Animals↗
Surgical treatment of scoliosis following poliomyelitis. A review of one hundred and ten cases.
We reviewed the cases of 110 patients with paralytic scoliosis due to poliomyelitis who were operated on. In the lumbar region, anterior Dwyer instrumentation with posterior fusion gave excellent correction of scoliosis and pelvic obliquity. In the more rigid thoracic curves, combined anterior Dwyer instrumentation and posterior fusion gave better results than posterior fusion alone, but had more morbidity. Long c-shaped curves benefited more from a combined anterior Dwyer procedure at the apex of the curve and long posterior Harrington instrumentation. Traction was found to be of use only in rigid curves and in those larger than 80 degrees. With combined anterior and posterior fusion, there was a pseudarthrosis rate of 7 per cent in lumbar curves, none in thoracic curves, and 12.5 per cent in long c-shaped curves. The pseudarthrosis rate rose to more than 25 per cent in patients who had a posterior fusion alone.
Adolescent↗
Biological properties of a human urinary protein fraction with burst promoting activity.
Urinary proteins from patients with iron deficiency anemia and acquired aplastic anemia were fractionated by chromatography on QAE-Sephadex A-50 and Sephadex G-25. Fractions containing erythroid burst promoting activity (code named regulatory protein RP) were separated from erythropoietin. Mouse bone marrow cells were preincubated for one day in suspension culture, in the presence or absence of RP, transferred to a methylcellulose based system and incubated for six more days with erythropoietin (EPO). It was found that the presence of RP in the preincubation medium had a 2 to 4 fold enhancing effect on subsequent erythroid burst colony formation. However, when RP was added to methylcellulose based cultures simultaneously with EPO, the erythroid burst response was reduced or abolished. Addition of RP to marrow cell suspension cultures increased the number of self replicating, pluripotent (erythroid/granuloid, E/G ratio = 3) spleen colony forming units (CFU-S) found at the end of 2 days incubation 3-5 fold over their number in control cultures incubated without the factor. In marked contrast to this, addition of EPO to the cultures caused an increased persistence of CFU-S with a predominantly erythroid commitment (E/G ratio = 19) and a low self replicating ability, as measured by retransplantation of spleen cells into secondary recipients. These observations are compatible with the presence in RP of a factor, or factors, capable of maintaining the size of certain early precursor cell compartments.
Anemia, Aplastic↗
Fat embolism in Hong Kong Chinese.
A prospective study on fact embolism showed that of ninety-five patients with a fractured shaft of the femur, seven (7 percent) demonstrated both pulmonary and cerebral disturbances, while there were profound disturbances in arterial PO2, hemoglobin level, pulse rate, and temperature in about 40 per cent of the patients. Using a modified Gurd test, a significant amount of fat was demonstrated in 5.7 per cent of the samples of venous blood and in 18.5 per cent of the samples of arterial blood.
Adolescent↗
Constancy of erythroid burst forming unit (BFUE) levels in the blood of hematologically normal individuals.
Repeated determination of circulating blood BFUE levels in 7 hematologically normal individuals, during a 6 to 16 month period, showed their respective levels to be maintained within narrow limits (coefficient of variation did not exceed 15.1%). However, males differed from each other 3-fold and females as much as 12-fold in the number of BFUE/ml blood. These differences may reflect various sizes of the early erythroid progenitor compartment, which in the presence of different levels of humoral regulators of erythropoiesis are capable of maintaining a normal rate of red cell production. Our findings suggest that the observation of changes of the blood BFUE level of individuals, over a period of time, may be indicative of a change in their erythropoiesis and may shed some light on the physiological role of the peripheral blood BFUE.
Blood Physiological Phenomena↗
The incidence of deep vein thrombosis in Hong Kong Chinese after hip surgery for fracture of the proximal femur.
Fifty-three Hong Kong Chinese patients with fractures of the proximal femur have been studied after hip surgery using functional ascending phlebograms for evaluating deep vein thrombosis. There was an incidence of deep vein thrombosis of 53.1 per cent in the fractured limbs and 14.3 per cent in the uninjured limbs. The majority of thrombi (84.6 per cent) were located in the calf. No clinical or fatal pulmonary embolism was observed.
Adult↗
A beneficial effect of the in situ kidney on in vitro marrow erythropoiesis in chronic renal failure.
The effect of the in situ kidney on transfusion requirements and in vitro erythropoiesis was investigated in 20 patients with end stage renal disease undergoing hemodialysis. 6 of the 12 patients with in situ kidneys did not require transfusion, whereas the other 6 had an average monthly transfusion requirement of 277 ml of sedimented RBCs. All 8 anephric patients required transfusions with an average requirement of 352 ml of sedimented RBCs per month. Serum erythropoietin activity was inappropriately low for the degree of anemia in all but 1 patient, and bone marrow was uniformly hypocellular. Marrow cells from patients with in situ kidneys exhibited a greater response to erythropoietin than marrow cells from their anephric counterparts. The response was not improved by hemodialysis.
Bone Marrow Cells↗
Acute myelomonocytic leukemia in children. Possible use of the soft agar culture technique in the differentiation of cellular subtypes.
In 8 children with acute myelomonocytic leukemia (AMML), colony formation in soft agar cultures derived from bone marrow cells was studied in an attempt to differentiate the monocytic (Schilling) from the myelomonocytic (Naegeli) types. The children did not differ markedly in their clinical and morphological parameters. Three in vitro growth patterns were observed: markedly decreased or no growth in 4 cases, extensive growth of granulocytic colonies in 2 cases, and extensive growth of macrophage colonies in the remaining 2. It is suggested that the marrows presenting diminished or no growth patterns are presumably of acute myelogenous leukemia patients with a monocytic component. The excessive granulocytic or macrophage colony growth may be an in vitro indication for an in vivo proliferation of either granulocytic or monocytic leukemic cell lines, and therefore may represent the Naegeli or Schilling variants of AMML respectively. If these observations can be approved in a larger series of AMML patients, this approach can be valuable as another tool in the differential diagnosis of the subtypes of AMML in children.
Adolescent↗
Suppression of mouse erythroid colony formation by L1210 leukemia cells.
The effect of L1210 transplantable leukemic cells on in vitro formation of erythroid colonies from CD2F1 mouse bone marrow progenitor cells (CFU-E) was investigated. Clonal cell culture was carried out by a methylcellulose technique. Human urinary erythropoietin served as the stimulator. After 44 hours of incubation aggregates of eight or more erythroid cells were scored as colonies. The number of CFU-E which could be demonstrated in marrow cells from mice that had been injected intravenously 6 days before with 5 x 10(4) L1210 cells was far below that obtained from normal marrow cells. When 1.3 x 10(5) marrow cells from leukemic mice or L1210 ascites cells were cultured with an equal amount of normal cells, the number of CFU-E expressed was reduced by 51% and by 86%, respectively, relative to controls with normal cells only. Neither lethally irradiated L1210 cells (4500 rad) nor L1210 cell conditioned media suppressed erythroid colony formation. It is suggested that in L1210 leukemia erythropoiesis is decreased because of a cell-to-cell inhibitory action of the leukemia cells on CFU-E.
Animals↗
Suppressive effect of interferon on erythroid cell proliferation.
The effect of interferon on mouse and human in vitro erythropoiesis was investigated using the mouse marrow CFU-E and the human blood BFU-E systems, respectively. Homologous interferons were found to have a marked inhibitory effect on mouse CFU-E and human BFU-E proliferation. This inhibitory effect was dose related and independent of the erythropoietin concentration used. The effective concentration of human interferon was within the range observed in humans following viral infections. It is suggested that interferon may play a role in the mechanism of the acute erythroblastopenic crisis observed at times in patients with chronic anemia following viral infections.
Adult↗
Exceptionally high serum erythropoietin activity in an anephric patient with severe anemia.
An exceptionally high serum erythropoietin (EPO) activity was documented in an anephric patient with severe anemia who required transfusions every 4 weeks. The patient's serum EPO was comparable to normal human urinary EPO in the polycythemic mouse assay and was neutralized by an antiserum against EPO. The patient's serum inhibited EPO stimulated-heme synthesis by normal human marrow cells in vitro. This finding suggests that an inhibitor played an important role in causing the anemia of this uremic patient.
Adolescent↗
Effect of residual kidney function on in vitro marrow erythropoiesis in chronic renal failure.
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ABO Blood-Group System↗
Immunological evaluation of combination therapy with tacrolimus and sirolimus on long-term allograft survival in nonhuman primates.
UNLABELLED: We reported that a 60-day course of combination therapy with tacrolimus and sirolimus induced long-term survival of renal allograft after withdrawal of immunosuppressants in Vervet monkeys. In the present study, the mechanism of drug-induced allograft survival was evaluated via Th1/Th2 cytokines, apoptosis and MLC activity in primates. MATERIALS AND METHODS: Cytokines were evaluated by ELISA. MLR and CTL assays were performed by incorporation of 72 hours (3)H-TdR and 4 hours (51)Cr release assay. RESULTS: A 60-day course of tacrolimus with sirolimus resulted in long-term survival of kidney allografts. (67% > 100 days) without intermittent acute rejection. Low sensitivity to MLR was seen in long-term renal allograft survival among monkeys treated with tacrolimus and sirolimus. Increased levels of CD3(+)CD8(+), CD3(+)/CD56(+) NKT cells and CD86(+)CD8(-)CD11(+) dendritic cells were observed. A population of high expression of CD4(+)FasL(+) was detected. In addition, the concentrations of IL-2 and IFN-gamma from long-term allograft surviving monkeys was not significantly increased, rather a late phase dominance of Th2, IL-4, IL-10, and TGF-beta was found correlated with long-term survival of recipients. In conclusion, the mechanism of tacrolimus and sirolimus induced long-term allograft survival in primates relates to up-regulated FasL expression, NKT cells and dendritic cells, with downregulation of MLR sensitivity. It is also associated with late-dominant expression of Th2 cytokines.
Animals↗
Anterior spinal fusion or deranged lumbar intervertebral disc.
Ninety-seven patients who underwent anterior interbody fusion for lumbar disc derangement were examined two to 15 years after the operation. Complete relief of back pain was obtained in 60% and of sciatica in 85%; marked improvement of back pain was obtained in 29% and of sciatica in 10%. The fusion rate was 63% and was only slightly correlated with symptomatic improvement. Many complications were encountered, most of which were transient.
Adolescent↗