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Biomedical subjects

H Ekert

Publications and source records attributed to H Ekert.

At least 55 records · Page 3Linked to original sources

An inhibitor to factor VIII:C in a patient with possible combined haemophilia A and von Willebrand's disease.

A factor VIII inhibitor has been found in a patient with an unusual combination of factor VIII-related properties. The inhibitor is directed specifically against the clotting activity (VIII:C) of the factor VIII complex. It behaves in a similar fashion to high responding inhibitors of factor VIII seen in haemophilia A patients and it was characterised as an immunoglobulin of the IgG class. Laboratory results from the patient and his family show considerable variation of factor VIII-related properties between various individuals. Overall, the data suggests the co-existence of haemophilia A and von Willebrand's disease in the family and the presence of both diseases in the patient.

Child, Preschool↗

Isolation of malignant cells from human bone marrow using a discontinuous Percoll gradient.

A technique for examining relatively large volumes of bone marrow for involvement by malignancy is described. The use of discontinuous Percoll gradients offers no advantage over conventional methods in the diagnosis of hematological malignancy. Its usefulness in detecting infiltration by solid tumor is uncertain. Complete exclusion of malignancy from the fraction containing hematologic stem cells in three patients raises the possibility that this technique is a useful adjunct to other methods of marrow purging before autologous marrow rescue in malignant disease.

Biopsy, Needle↗

Marrow function reconstitution by fraction 3 of Percoll-density-gradient-separated cells.

Eight children with advanced tumors or acute myeloid leukemia were treated either with very-high-dose multi-agent chemotherapy (4) or marrow ablative high-dose melphalan (4) followed by autologous marrow rescue, using only fraction 3 from a Percoll-discontinuous density gradient separation of bone marrow buffy coats. Each patient received less than 20% of the number of cells usually reinfused from the buffy coat. The yield of CFU-c in Percoll gradient 3 was similar to the yield obtained from whole buffy coats of bone marrow. Reconstitution of marrow function with a neutrophil count greater than 0.5 X 10(9)/L and platelet count greater than 50 X 10(9)/L occurred in 7 patients in a medium time of 15 and 16 days, respectively--a time comparable to that following infusion of whole buffy coat in 20 other patients. In one patient, hemopoietic recovery was considerably delayed, suggesting that fraction 3 from the Percoll gradient had been relatively ineffective in marrow reconstitution. We conclude that fraction 3 from marrow separated on Percoll gradients has the advantages of small volume and good recovery of marrow stem cells and can promptly reconstitute marrow function in the majority of children treated with very-high-dose chemotherapy or marrow ablative doses of melphalan.

Adolescent↗

Use of heat-treated clotting-factor concentrates in patients with haemophilia and a high exposure to HTLV-III.

In a group of 126 Australian patients with haemophilia, who were receiving lyophilized clotting-factor concentrates prepared from locally collected plasma, a high prevalence of antibody to human T-cell lymphotropic virus III (HTLV-III) was demonstrated in those with severe disease. Patients with moderate or mild disease had a much lower prevalence of HTLV-III antibody. After heat treatment of lyophilized factor VIII and factor IX concentrates (60 degrees C for 72 hours) to inactivate the virus, the losses of activity of an intermediate-purity and of a fibrinogen-poor factor VIII concentrate, and of the coagulant activity of a factor IX concentrate, were within acceptable limits. The solubility of the intermediate-purity factor VIII concentrate was markedly decreased; the fibrinogen-poor factor VIII concentrate and the factor IX concentrate were readily soluble. In-vivo recovery and survival of heated concentrates were equivalent to those of the unheated products, and they were effective in the treatment of spontaneous and traumatic haemorrhages.

Acquired Immunodeficiency Syndrome↗

Establishment and partial characterisation of a human fibrosarcoma cell line MR-83.

We describe a mycoplasma-free human fibrosarcoma cell line, MR-83, which grows readily in liquid culture and as clones in semi-solid agar with a plating efficiency of about 0.5%. It has a stable karyotype consisting of a modal number of 49-51 chromosomes, with two translocations and a deletion. The cell line shows resistance to adriamycin in semi-solid agar assay, and responds to Epidermal Growth Factor (EGF) by increased DNA synthesis, as measured by thymidine uptake.

Cell Division↗

Experience with high dose multiagent chemotherapy and autologous bone marrow rescue in the treatment of twenty-two children with advanced tumours.

Intensive chemotherapy followed by infusion of cryopreserved autologous bone marrow (ABMR) was used in the treatment of 22 children with advanced tumours. In nine this was their initial therapy; in eight it was used after partial or complete remission had been achieved with standard therapy; and in five, after relapse had occurred. Recovery of marrow function occurred in 20 patients with a mean time of 13.2 and 18.2 days to recovery of neutrophils (greater than 0.5 X 10(9)/l) in newly diagnosed and previously treated patients respectively. Platelet count recovery to greater than 50 X 10(9)/l occurred in a mean time of 13.4 days in newly diagnosed and 20.4 days in previously treated patients. Control of extensive local tumour was obtained in three of three evaluable patients with abdominal non-Hodgkin's lymphoma (NHL). Metastatic bony and marrow disease was controlled in two of two patients with retinoblastoma. In Ewing's sarcoma, temporary control of widespread metastatic disease occurred in one patient. In the other, eradication of extensive local mass disease at the primary site had been achieved. Poor response to treatment has been seen in seven of eight patients with Stage III or IV rhabdomyosarcoma, three patients with neuroblastoma and four of five patients with recurrent disease. Apart from the anticipated bone marrow toxicity, the major complications were severe mucositis, anaphylaxis following bone marrow infusion and haemorrhagic cystitis. The presence of herpes simplex infection appeared to aggravate mucosal complication.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Familial deficiency of antithrombin III: evidence for heterogeneity existing within the family.

An Australian family with familial antithrombin III (AT III) deficiency is described. The deficiency inherited in an autosomal co-dominant manner is characterised by proportionate reduction in antigenically and biologically measured AT III. Some members with AT III deficiency have had major venous thromboses, and the deficiency has possibly been the cause of death in two individuals in the family. Heterogeneity was observed in laboratory and clinical findings in this family.

Adult↗

Factor VIII procoagulant antigen recovery is a dose-related response to Factor VIII concentrate infusions.

The recovery and initial half-disappearance rate of factor VIII procoagulant activity (VIIIC) and procoagulant antigen (VIIICAg) were studied in 9 haemophilia A patients following infusion of factor VIII concentrates to varying plasma VIIIC levels. While VIIIC recovery was independent of dose, the VIIICAg recovery varied in a dose-dependent fashion. The excess of VIIICAg relative to VIIIC found in the factor VIII concentrates (VIIICAg/VIIIC ratios of 1.9-3.1) was not observed in plasma samples taken after low level infusions (plasma VIIIC less than 1 U/ml) but a significant excess of VIIICAg was observed in higher level infusions. The VIIICAg recovery of post-infusion plasma was not increased by treatment with phospholipase C.

Antigens↗

Left shift in the peripheral blood count at diagnosis in acute lymphocytic leukemia is significantly correlated with duration of complete remission.

The prognostic significance of a left shift in the peripheral blood at the time of diagnosis of acute lymphocytic leukemia was investigated by a retrospective analysis of 109 patients treated on the same protocol in a single institution. Left shift was defined as the presence of 1% or more of metamyelocytes, myelocytes, or promyelocytes. All peripheral blood films were checked at the time of diagnosis by one of the authors. It was found that the duration of complete remission at 92 mo was 74% in patients with left shift and 42% in those without left shift (p less than 0.05, log-rank test). By Cox regression analysis, only the total white cell count (p less than 0.001) and the presence or absence of left shift (p less than 0.01) were independently significant in determining the proportion of patients in complete remission. Patients with a left shift had a significantly higher granulocyte count at diagnosis (p less than 0.05). We postulate that left shift in the peripheral blood count at the time of diagnosis may be an indirect measure of the total leukemia cell load. It is a new prognostic factor of significance in determining the likely outcome of the disease.

Adolescent↗

Results of treatment of 18 children with Hodgkin disease with MOPP chemotherapy as the only treatment modality.

Eighteen children with Hodgkin disease (16 previously untreated; two relapsed) were treated with MOPP chemotherapy (nitrogen mustard, vincristine, prednisone, procarbazine) only. Ten had clinical stage I and II disease, four had stage III, and four had stage IV. In ten patients, the clinical stage was confirmed by staging laparotomy. Six courses of MOPP were given to eight stage I and II patients and two stage IV patients. Between 7 and 12 courses were given to two stage I and II, and six stage III and IV patients. Dose reduction of 75-50% was required in 13% and delay of treatment in 22% of the first six courses of MOPP. Hematologic toxicity, minor and major viral infections, and nausea and vomiting were the major complications. Complete remission (CR) was obtained in 17 patients. Of these 17, there has been one death in CR, and one relapse. Sixteen patients have discontinued treatment and have been observed off treatment for 8 months to 7.5 years. The actuarial disease-free survival with a median follow-up of 28 months is 80% and overall survival is 92%.

Adolescent↗

The treatment of Wilms' tumor: results from Royal Children's Hospital, Melbourne, 1967-1977.

A retrospective review of the treatment of Wilms' tumor from 1967 to 1977 at the Royal Children's Hospital, Melbourne, was undertaken, allowing a minimum 2-yr followup. Fifty-four (77%) of the 70 patients in the study are alive, with 23/25 (92%) in Stage I, 12/16 (75%) in Stage II, 12/19 (63%) in Stage III, and 7/9 (78%) in Stage IV. Survival was significantly better in Stage I disease, and those patients less than 5-yr-old at presentation. Recurrence of disease was significantly lower after the introduction of multiple courses of chemotherapy in 1971. Sixteen deaths occurred during the period: three infants from drug toxicity, four patients with "unfavorable" sarcomatous histology, and four patients with recurrent local disease, where irradiation had been confined to the tumor bed after tumor spill with recurrence beyond the irradiated field.

Abnormalities, Multiple↗

VM-26 and dimethyl triazeno imidazole carboxamide in Ewing's sarcoma.

Twenty-seven patients with biopsy proven Ewing's sarcoma were randomised to receive one of two adjuvant chemotherapy regimens for two years. Group A were given monthly courses of vincristine, adriamycin and dimethyl triazeno imidazole carboxamide (DIC); Group B received monthly courses of VM-26, adriamycin and DIC. Chemotherapy was commenced after biopsy confirmation of disease. The primary tumour was treated with irradiation to 3,000-5,000 rad and by resection in three patients. With a median follow-up of 26 months, 52% of patients are disease free. Ten patients died, seven from recurrent disease and three from complications of treatment. There was a significant difference in disease free survival rate of patients with long bone lesions (11/12) compared with patients with flat bone lesions (6/15). The disease free survival rate of Groups A and B was similar. Our results suggest that in combination chemotherapy for Ewing's sarcoma, vincristine and VM-26 have similar anti-tumour activity.

Adolescent↗

A comparison of "carrier screening" of hemophilia by the ratio of factor VIII coagulant activity or antigen to factor VIII related antigen.

The ratio of factor VIII coagulant activity (VIIIC) or antigen (VIIICAg) to that of factor VIII related antigen (VIIIRAg) was measured in 15 normals, 21 obligatory and 23 possible carriers of hemophilia. Factor VIII coagulant was measured on fresh plasma samples whereas antigenic properties were measured on frozen and thawed samples. In obligatory carriers only, the mean level of VIIICAg was significantly lower than VIIIC and there was a tendency for low VIIICAg levels to be associated with raised VIIIRAg levels. Using both ratios, 13 obligatory carriers were outside the normal tolerance ellipse. In possible carriers, neither ratio showed superior discriminating power. In reference laboratories that perform carrier studies on stored or transported specimens, measurement of VIIICAg/VIIIRAg is a suitable test for diagnosis of carriers.

Antigens↗