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Biomedical subjects

A Wasunna

Publications and source records attributed to A Wasunna.

14 recordsLinked to original sources
PubMed1990

C-reactive protein and bacterial infection in preterm infants.

Serum C-reactive protein (CRP) concentration was measured by a new solid phase ligand-binding radiometric monoclonal antibody immunoassay in a prospective study of 193 consecutively born preterm infants. In 104 with no clinical or laboratory evidence of infection the median CRP in cord serum was 0.125 mg/l (range 0.011-6.0 mg/l), at 24 h it was 1 mg/l (0.016-7.0) and at 48 h 2 mg/l (0.400-8.0). The present highly sensitive assay has enabled these normal ranges to be defined for the first time, at levels below the threshold of non-labelled immunoassays and of all commercially available CRP assays. The values in cord serum were significantly lower than in normal healthy adults (median 0.8 mg/l, range 0.07-29 mg/l, n = 468). Arterial catheterisation and endotracheal intubation, in the absence of infection, did not appear to elevate CRP, nor did cerebral germinal layer or intraventricular haemorrhage. Among nine infants with confirmed septicaemia eight had a serum CRP level raised at least once during the first 48 h and serum CRP in the other one increased 250-fold in 24 h before treatment was started. Using this assay, serum CRP is a useful and rapidly available adjunct to clinical assessment in diagnosis and exclusion of bacterial infection in the early neonatal period, has encouraged us to withhold or discontinue antibiotics and also has a role in monitoring response to treatment.

Antibodies, Monoclonal↗
PubMed1987

Aflatoxin exposure measured by urinary excretion of aflatoxin B1-guanine adduct and hepatitis B virus infection in areas with different liver cancer incidence in Kenya.

Two major etiological agents, hepatitis B virus and aflatoxin B1, are considered to be involved in the induction of liver cancer in Africa. In order to elucidate any synergistic effect of these two agents we conducted a study in various parts of Kenya with different liver cancer incidence in order to establish the rate of exposure to aflatoxin and the prevalence of hepatitis infections. Of all tested individuals 12.6% were positive for aflatoxin exposure as indicated by the urinary excretion of aflatoxin B1-guanine. Assuming no annual and seasonal variation, a regional variation in the exposure was observed. The highest rate of aflatoxin exposure was found in the Western Highlands and Central Province. The incidence of hepatitis infection nationwide as measured by the presence of the surface antigens was 10.6%, but a wide regional variation was observed. A multiplicative and additive regression analysis to investigate if hepatitis and aflatoxin exposure had a synergetic effect in the induction of liver cancer was negative. However, a moderate degree of correlation between the exposure to aflatoxin and liver cancer was observed when the study was limited to certain ethnic groups. The study gives additional support to the hypothesis that aflatoxin is a human liver carcinogen.

Aflatoxin B1↗
PubMed1987

Pulse oximetry in preterm infants.

One hundred and twenty five measurements of arterial oxygen saturation (Stcao2) obtained with a transcutaneous pulse oximeter were compared with direct arterial oxygen tension (Pao2) in 13 preterm infants with predominantly fetal haemoglobin. Stcao2 of 86-92% corresponded to Pao2 of 5-13 kPa. Stcao2 above 92%, however, was sometimes associated with Pao2 above 13 kPa.

Humans↗
PubMed1985

Detection of 8,9-dihydro-(7'-guanyl)-9-hydroxyaflatoxin B1 in human urine.

A possible role of aflatoxin B1 (AFB) in the etiology of human liver cancer has been suggested from several epidemiological studies. This has been based upon the association between consumption of AFB-contaminated food and the liver cancer incidence in different parts of the world. To further establish the role of AFB as a major factor, we initiated a pilot study in three different districts of Kenya to determine the number of individuals exposed to significant amounts of AFB as measured by the urinary excretion of 8,9-dihydro-8-(7-guanyl)-9-hydroxyaflatoxin B1 (AFB-Gua), an adduct formed between the ultimate carcinogenic form of AFB and nucleic acids. This product has previously been detected in urine from rats treated with AFB. Urine collected at the outpatient clinics at the district hospitals were concentrated on C18 Sep-Pak columns and analyzed by high-pressure liquid chromatography under two different chromatographic conditions. The chemical identity of the samples showing a positive response in both chromatographic systems was verified by synchronous scanning fluorescence spectrophotometry. The highest number of individuals with detectable urinary AFB-Gua lived in either Murang'a district or the neighboring Meru and Embu districts. In Murang'a district a rate of 12% was observed in the January-March period, while only 1 of 32 patients (3%) had a detectable exposure in July-August.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Lymphocyte enzyme activities in East African blacks: decrease in 5'nucleotidase and possible relation to immunosuppression.

Microanalysis of subcellular organelle marker enzymes was applied to cryopreserved lymphocytes (obtained and processed in the field) from East African blacks with moderate to severe malnutrition and subject to locally endemic parasitic and infectious diseases. An initial study demonstrated that activities of these enzymes, with the partial exception of catalase, were stable to cryopreservation. Cryopreserved and thawed lymphocyte specimens (1 to 3 X 10(6) viable cells) from 26 Africans and 20 Caucasian controls were studied. There was a highly significant decrease in 5'nucleotidase activity in these African subjects. Activity of another plasma membrane enzyme, gamma-glutamyl transferase, and of marker enzymes for other intracellular organelles, was not significantly different between the two groups, indicating that the nucleotidase alteration is highly specific. 5'Nucleotidase activity in a group of 17 East African blacks of high socio-economic status lay between the values obtained in the other two groups and was not significantly different from either. Further studies on 5'nucleotidase showed no evidence that the enzyme is functionally different in Africans. The differences in activity of this enzyme in Africans may reflect the known immuno-suppressive effects of infectious disease and malnutrition or may have a genetic basis which may in turn be associated with the pathogenesis of secondary immunodeficiency.

5'-Nucleotidase↗
PubMed1983

Detection of putative adduct with fluorescence characteristics identical to 2,3-dihydro-2-(7'-guanyl)-3-hydroxyaflatoxin B1 in human urine collected in Murang'a district, Kenya.

Food samples collected in Murang'a district, Kenya are known to be contaminated with a mycotoxin, aflatoxin B1 (AFB), and a positive correlation exists between the dietary intake of AFB and the incidence of liver cancer. When urine samples collected in this district were analyzed for the presence of 2,3-dihydro-2-(7'-guanyl)-3-hydroxyaflatoxin B1 (AFB-GuaI) by h.p.l.c., 6 of 81 samples had a detectable level of a compound whose fluorescence spectrum was identical to chemically synthesized AFB-GuaI as confirmed by photoncounting fluorescence spectrophotometry. These results are an indication of interaction between the ultimate carcinogenic form of AFB and cellular nucleic acids in vivo and further support the hypothesis that AFB may play an important role in the etiology of human liver cancer.

Aflatoxin B1↗
PubMed1982

HLA antigens in East African Black patients with Burkitt's lymphoma or nasopharyngeal carcinoma and in controls: a pilot study.

A pilot study is reported of HLA-A, B, and C antigens in 141 East African Blacks comprising patients with Burkitt's lymphoma or nasopharyngeal carcinoma, either with active disease or in long-term remission, together with comparable controls. This study forms part of a wider program investigating host factors in these diseases. A protocol was selected for optimal testing of cells processed and cryopreserved between 1972 and 1976, largely under field conditions, which employed a two-color fluorochromasia typing procedure. Antigen distribution and computed haplotype frequencies in the total unrelated population are given. New findings include an approximately equal frequency of Aw23 and Aw24, a high (18%) incidence of Bw21, and the gametic associations of Aw36 with Bw44, and Aw30 with Bw45. Of the major group of B15-related antigens reported earlier. SV is the most common, and there are strong linkages of SV with Cw2 and Bu with Cw3. The possible presence of further variants at the A- and B-loci is reported. The proportion of B-locus antigen "blanks" in this study is 5.9%. Relationships have been sought between the HLA antigens and diseases studied: the antigen A29, possibly in linkage with Bw42, shows a correlation with disease susceptibility, and associations are suggested between Bw44 (in possible combination with Aw36) and resistance to both BL and NPC, and between Bw45 and long-term remission in NPC.

Adolescent↗
PubMed1980

B15 heterogeneity in East African Blacks.

One-hundred-forty-one Blacks (135 unrelated) from Kenya and Tanzania have been tissue-typed (HLA-A, B and C loci) as part of a study of host factors involved in Burkitt's lymphoma and naso-pharyngeal carcinoma. Evidence is presented for the existence in this population of several B15-related antigens which together occur with a relatively high frequency of 30% in unrelated individuals. It is likely that these variants may include the antigens SV and perhaps Bu recently defined with population frequencies of under 1% in Caucasians. In the absence of monospecific typing sera, identification of these variants may be helped by their apparently strong association with C-locus antigens in Blacks. Recognition of these B15 variants has been largely responsible for reducing the proportion of unidentified or "blank" B-locus antigens in this population to only 6%. These findings substantiate and amplify previous reports suspecting the presence of such antigens in Blacks, and should facilitate studies of possible associations of disease with HLA in these populations.

Africa, Eastern↗
PubMed1978

Retrospective study of carcinoma of the esophagus in Kenya.

A clinical, radiological, histological, and geographical study of carcinoma of the esophagus in Kenya is reported. It was found that this cancer is diagnosed more often in males than in females, with a ration of 8:1 (Kenya Cancer Registry). The most common age in males and females is 50 to 59 years. The regions of the esophagus most commonly involved are the middle and lower thirds, in almost equal proportions. An unexplained tendency for the tumor to be poorly differentiated towards the lower third is noted. In addition a review on the possible etiological factors is presented.

Age Factors↗
PubMed1977

The mitogenic response of cryopreserved human lymphocytes in a microculture system.

Fresh blood lymphocytes from nine health donors have been compared with samples from the same donors, recovered after period of 2 to 21 months storage in liquid nitrogen, for the capacity to respond to a range of mitogens in vitro. A microculture assay was used, requireing aliquots of only 25,000 cells. The mean levels of 14C-thymidine uptake for fresh and frozen samples were closely comparable when the cells had been stimulated by PHA, Pokeweed or mitomycin-C-treated allogeneic lymphoblastoid cells. Lymphocytes from six East African donors, frozen by a very simple technique, were recovered after 3 or more years storage in liquid nitrogen. Five of the samples were in good condition as judged by cell viability and the capacity to form spontaneous 'E' rosettes with sheep erythrocytes. These five samples also responded extremely well to PHA, PWM and mitomycin-C-treated allogeneic lymphoblastoid cells using the microculture assay. This study extends the range of applications of cell banks in which small aliquots of blood lymphocytes are stored in liquid nitrogen for periods of several years.

Adult↗