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Biomedical subjects

K Williams

Publications and source records attributed to K Williams.

At least 487 records · Page 27Linked to original sources
PubMed1978

A new variant of human erythrocyte G6PD occurring at a high frequency amongst the population of two villages in The Gambia, West Africa.

During the course of a large survey of red cell G6PD genotypes in The Gambia, a slow electrophoretic variant with reduced enzyme activity was found to occur at a high frequency. This variant, G6PD Gambia, was found in the following genotypic combinations: males; G6PDGam, females; G6PDA+/Gam, G6PDB+/Gam, and G6PDA-/Gam. From the electrophoretic mobility and kinetic characteristics it was concluded that G6PD Gambia was a hitherto unreported variant of G6PD. The frequency of the G6PDGam gene amongst the 1109 individuals examined was 0.024.

Erythrocytes↗
PubMed1978

Clearance of myelin basic protein from blood of normal and EAE rabbits.

The rate of clearance of porcine myelin basic protein (MBP) from plasma of rabbits was determined following intravenous injection of 20 mg MBP. The MBP level in the plasma was measured by a 2-site immunoradiometric assay with specific antibody to guinea pig MBP produced in rabbits. Plasma MBP-antibody levels were determined by competitive binding radioimmune assay (RIA). Unsensitized and those sensitized with complete Freund's adjuvant (CFA), with porcine MBP in CFA, and with whole porcine spinal cord in CFA were studied. Unsensitized and CFA sensitized rabbits exhibited maximum MBP levels in the plasma within two minutes after injection with rapid decrease to undetectable levels in one hour. Thirty-nine of the unsensitized (control) rabbits exhibited normal, rapid clearance and no subsequent physical signs of EAE while one of the control rabbits exhibited a slightly retarded clearance rate. Histologic examination of autopsy tissues from the control group revealed that five rabbits showed lesions which could be attributed to Encephalitozoan cuniculi or Toxoplasma and one rabbit autopsied 65 days after clearance had minimal EAE lesions. Rabbits sensitized with MBP exhibited a retarded rate of clearance at the acute stage of EAE and following recovery. Rabbits sensitized with whole spinal cord in CFA also exhibited a retarded rate of MBP clearance. Anti (MBP) antibodies were detected in the plasma of all rabbits which exhibited a retarded rate of MBP clearance. Significant rates of retardation were not detected until approximately three weeks after sensitization with CFA-MBP or CFA-spinal cord. While MBP antibody levels in most animals were not detected by the immunodiffusion technique, antibodies were demonstrated by RIA. The 20 mg MBP given intravenously is probably in great antigen excess and conducive to the formation of soluble MBP-anti (MBP) complexes in the blood.

Animals↗
PubMed1978

Observations on the treatment of an acute attack of migraine.

In 1976, 310 patients attended the Princess Margaret Clinic for treatment of an acute headache. 90% were either symptom-free or had only slight residual headache after 4 h. The treatment given was metaclopramide and an effervescent analgesic. 69% of patients had some form of sedation and 10% ergotamine tartrate. Those patients who had treatment between 6 and 12 h following the onset of an attack had significantly fewer attacks in the next 7 days. Patients who slept during an attack, with a sedative where indicated, recovered more quickly than those who did not sleep. The depth of sleep did not affect the rate of recovery. A higher percentage of patients with migraine compared with those with tension headache were either symptom-free or had only slight residual headache on leaving.

Acute Disease↗
PubMed1977

Renal transplantation and a positive serological cross-match.

A renal transplant involving a recipient with a positive serological cross-match against donor lymphocytes generally results in hyperacute rejection of the graft. 13 cadaveric renal transplants were performed in recipients with a known positive serologic cross-match against donor B lymphocytes. 12 of these serological cross-matches were positive against donor blood, node, or spleen lymphocytes, but the reactivity was directed against donor B lymphocytes only. 3 transplants failed, 2 because of rejection and 1 because of renal-artery thrombosis. 10 transplants are functioning, 6 to 42 weeks after the operation. Of these 10 successful grafts, 3 had no acute rejection episodes, while 7 had an early acute rejection episode which responded to treatment. Histologically, the grafts showed a cellular rejection, similar to that in enhanced renal allografts in the rat. It is possible to transplant a kidney in a high-risk patient with a positive B lymphocyte cross-match with a low risk of failure. In addition active enhancement of the graft might sometimes occur.

Acute Disease↗
PubMed1977

The Duffy blood group and malaria prevalence in Gambian West Africans.

Erythrocytes from 1,168 donors, comprising almost the entire populations of two rural Gambian villages, have been tested for Duffy blood group antigens using antisera to both Fya and Fyb. All tests were negative. Blood film examination of the same samples showed complete absence of Plasmodium vivax parasitaemia, but infections with P. falciparum,P. malariae and P. ovale were observed. The findings are consistent with the view that the Duffy-negative phenotype, FyFy, constitutes the basis of innate resistance towards infection with P. vivax but not towards infection with the other plasmodial species.

Black People↗
PubMed1977

Influenza infections during pregnancy in the mouse.

The effect of a sublethal dose (0-5 LD50) of influenza A/WSN (H0N1) administered intranasally in the 1st and 3rd weeks of pregnancy was studied in C3H inbred mice. Maternal and neonatal mortality rates were significantly increased by infections in the 3rd week of pregnancy, but not in the 1st week. Infections during the last part of the 1st week significantly depressed the growth rate of neonates. No evidence of viraemia, transplacental transmission or congenital malformations were observed from infections during either week. The results are discussed in terms of a possible model for human influenza infections during pregnancy to determine the potential risks to the mother, fetus and neonate.

Animals↗
PubMed1977

The use of transportable single-radial-diffusion immunoplates in seroepidemiological studies of influenza in the Gambia. The occurrence and persistence of antibody to influenza A/Hong Kong/68 (H3N2) virus in selected inhabitants of two rural villages.

Seroepidemiological studies of influenza in the Gambia were made using transportable single-radial-diffusion immunoplates containing A/Hong Kong/68 (H3N2) virus as antigen. The frequency and durability of antibody so detected in selected residents of two Gambian villages (Manduar and Kafuta) are described. Transportable immunoplates were found to be an effective method for the serological surveillance of influenza and to be applicable in studies in remote areas where laboratory facilities may not be available. Results indicated that infection with influenza was widespread in Manduar residents on several occasions between 1968 and 1974 and that reinfection with A/Hong Kong/68 virus or its antigenic variants occurred frequently. Serum levels of antibodies to the haemagglutinin and neuraminidase antigens of the A/Hong Kong/68 virus often persisted for only a short time (mean half-life about 28 days), particularly after first infections. Antibody persistence increased following repeated reinfection. No precise explanation can be offered at present for the relatively short persistence of antibodies in Gambians. Possible reasons include genetic and environmental factors, depressed immunological reactivity associated with concurrent infection (notably parasitic diseases), and unusually high rates of synthesis and catabolism of immunoglobulins. The value of transportable immunoplates for serological surveys and for accurate assessment of antibody persistence is discussed.

Adolescent↗
PubMed1976

L-asparaginase reinduction and maintenance therapy in previously treated acute lymphocytic leukemia.

Four patients with acute lymphocytic leukemia previously treated with conventional chemotherapy received intramuscular L-asparaginase in combination with other chemotherapy for reinduction and maintenance therapy. These patients received the L-asparaginase for 8, 14, 27, and 34+ months without demonstrating any significant adverse effects. Only 1 of the 4 was clearly resistant to the other chemo-therapy, and 3 of 4 had recurrence of their disease while receiving L-asparaginase. L-asparaginase can be added to reinduction and maintenance regimens of patients resistant to other chemotherapy and is well tolerated for long periods when given intramuscularly weekly with other immunosuppressant agents.

Adolescent↗
PubMed1976

Precipitating antibody response to malarial S-antigens.

The gel diffusion test has been used to detect antibodies to malarial S-antigens. Sera were obtained from entire Gambian village communities, from young children with acute P. falciparum malaria, from children convalescent from such infections and from immune adults. In community studies, small selections of S-antigens detected antibody frequently in sera from older persons but rarely in sera from young children. Larger panels of antigens detected antibodies in sera from half of 50 malarious children while homologous antibody responses were observed in 22% of 267 children followed at intervals during convalescence from malaria. In these latter cases, antibody tended to appear more swiftly when antigen was lost rapidly from the circulation, and observations made on individual responses indicated that antibody production was influenced by factors other than the intrinsic properties of the antigens. In adult sera antibodies usually occurred in association with IgG.

Adolescent↗
PubMed1976

Anti-inflammatory actions of dapsone and its related biochemistry.

Dapsone has been examined by two established animal anti-inflammatory models and found to possess anti-inflammatory activity comparable with established non-steroidal anti-inflammatory drugs. Dapsone also possess some biochemical properties common to other anti-inflammatory drugs.

Animals↗
PubMed1975

The short arm deletion syndrome of chromosome 4 (4p- syndrome).

Partial deletion of the short arm of chromosome 4 (4p-) represents another (rare) cause of cleft lip and cleft palate. Further characteristic manifestations of the syndrome (also called Wolf or Wolf-Hirschhorn syndrome) are growth failure, microcephaly, prominent glabella, hypertelorism, beaked nose, poorly differentiated and low set ears, cardiac and renal malformation and hypospadias. Life expectancy is often shortened. The 4p- syndrome has many features in common with another deletion syndrome, the cri-du-chat syndrome, and also with the Smith-Lemli-Opitz syndrome. The latter is a hereditary condition with normal karyotype. The cri-du-chat syndrome is characterized by a peculiar high-pitched, mewing cry and can be differentiated from the Wolf syndrome by the different staining characteristics (banding) of chromosomes 4 and 5.

Abnormalities, Multiple↗
PubMed1975

Occurrence of S-antigens in serum in Plasmodium falciparum infections in man.

Gambians with severe Plasmodium falciparum infections frequently have malarial S-antigens in their serum or plasma. Detection of these with the available antisera which are from immune adults is complicated because there are many different S-antigens and none of the antisera contains antibodies to them all. Despite this we found S-antigens in about 60% of a large series of malarious children and demonstrated that this was a considerable underestimate of the true incidence. We also showed that the prevalence of S-antigens was related to the malaria season and to the intensity of infection.

Antigens↗