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Biomedical subjects

T Jenkins

Publications and source records attributed to T Jenkins.

At least 199 records · Page 11Linked to original sources
PubMed1984

The haemoglobin H disease mental retardation syndrome: molecular studies on the South African case.

The child with haemoglobin H (HbH) disease and multiple congenital abnormalities reported by Borochowitz et al (1970) has been more fully investigated in view of the recent report by Weatherall et al (1981) of a 'new' syndrome of HbH disease and mental retardation. Restriction enzyme analysis indicates that the child's HbH disease results from the inheritance of an alpha-thalassaemia 2 chromosome (-alpha/) from his mother and, from his father, a chromosome which has undergone a deletion including the zeta- and alpha-globin genes as well as an undefined length of DNA. Striking similarities between our patient and Weatherall et al's patients at the clinical level and between our patient and their patient number 1 at the molecular level, confirm that a new syndrome has been defined.

Abnormalities, Multiple↗
PubMed1984

A newly recognized feature of ectrodactyly, ectodermal dysplasia, clefting (EEC) syndrome: comedone naevus.

A 21-year-old Black South African man with clinical features of ectrodactyly, ectodermal dysplasia, cleft lip/palate (EEC) syndrome is described. The patient had the following anomalies: hypoplastic, peg-shaped teeth; fine, silky hair; absent lacrimal puncta resulting in secondary photophobia, blepharitis and corneal opacities. The hands and feet showed absent digits, symphalangism and displacement of bone consistent with ectrodactyly. In addition, the patient had extensive comedone naevus, a feature not previously reported in EEC syndrome. We stress that the dysplastic ectodermal features of EEC syndrome are not typical of either hidrotic or anhidrotic ectodermal dysplasia but fall into a class of their own. Clefting of the lip and palate were absent due, it is postulated, to the variable expressivity of EEC syndrome.

Adult↗
PubMed1983

Evaluation of a testicular sperm head counting technique using rats exposed to dimethoxyethyl phthalate (DMEP), glycerol alpha-monochlorohydrin (GMCH), epichlorohydrin (ECH), formaldehyde (FA), or methyl methanesulphonate (MMS).

Single dosages of DMEP (1,000-2,000 mg/kg), GMCH (50 mg/kg), ECH (25 and 50 mg/kg), FA (100 and 200 mg/kg), and MMS (100-400 mg/kg) were administered orally to 10 week old male Wistar rats. The rats were necropsied on the 11th day following dosing. The testes were weighed, homogenised and sonicated; numbers of sperm heads (total and abnormal) were counted and percentage sperm head abnormalities were calculated. Testes weights were significantly reduced only in rats exposed to 1,500 and 2,000 mg DMEP/kg. Compared with controls, there were significant increases in the incidence of abnormal sperm at all dose levels of MMS and the higher dose levels of DMEP (1,500 and 2,000 mg/kg), ECH and FA. No toxicologically significant effects upon total sperm counts were seen following the oral administration of any of the five chemicals tested. However, an additional group of rats given 100 mg MMS/kg intraperitoneally (i.p.) showed significant reductions in testes weight and total sperm head counts compared with control animals. It is concluded that this testicular sperm head counting technique is a useful tool in the detection of selective adverse effects of chemicals upon testicular sperm but requires further evaluation.

Animals↗
PubMed1983

Sero-genetic studies on the Caucasoids of South West Africa/Namibia.

Gene marker studies on the Afrikaans and German populations of South West Africa/Namibia reveal that both very closely resemble their parent European stocks but that the Germans show appreciable evidence of having received a genetic contribution from non-Caucasoid, probably Khoi or Negro, sources.

Blood Group Antigens↗
PubMed1983

Genetic heterogeneity in partial adenosine deaminase deficiency.

Inherited deficiency of the enzyme adenosine deaminase (ADA) results in a syndrome of severe combined immunodeficiency (SCID). Children with ADA- -SCID lack ADA in all cells and tissues. In contrast, a "partial" deficiency of ADA has been described in six immunologically normal children from four different "families." These children lack ADA in their erythrocytes but retain variable amounts of activity in their lymphoid cells. We have examined ADA activity in lymphoid line cells from four of these children, who are unrelated, for evidence of genetic heterogeneity. One child, who is Caucasian, has an enzyme with increased electrophoretic mobility, a diminished isoelectric point (pI 4.8 vs. Nl = 4.9) and very low activity (2.3 vs. Nl = 82.9 +/- 12.9 nmol/mg protein per min); as a second child has an enzyme with normal electrophoretic mobility but increased isoelectric point (pI = 5.0), markedly diminished heat stability at 56 degrees C (t1/2 = 4.2' vs. Nl = 40') and low activity (12.1); a third has an enzyme with only diminished heat stability (t1/2 = 6.5'), no detectable abnormality in charge and almost normal activity (41.9); while the fourth exhibits only diminished ADA activity (25.0) with no striking qualitative abnormalities. Thus, we have found evidence for three different mutations at the structural locus for ADA in three of these individuals, (a) an acidic, low activity heat stable mutation (b) a basic, somewhat higher activity, heat labile mutation, and (c) a relatively normal activity heat labile mutation. In the fourth, there is as yet no compelling evidence for a mutation at the structural locus for ADA and a mutation at a regulatory locus cannot be excluded.

Adenosine Deaminase↗
PubMed1982

Common birth defects in South African Blacks.

The prevalence rates of some of the common birth defects have been ascertained in a Black population in South Africa. The births of 29,633 infants were studied retrospectively from hospital records. The commonest defect was found to be polydactyly (10,4/1,000 births), and the other defects investigated were talipes equinovarus (1,55/1000 births), hydrocephalus (1,3/1,000 births), spina bifida and anencephaly (0,78 and 0,40/1,000 births respectively) and facial clefts (0,30/1,000 births). These rates were compared with those found in other population groups in South Africa and, in some cases, in other African countries and in Negro groups in the USA and Canada.

Black or African American↗
PubMed1982

Neoplasia of the larynx in the dog.

The clinical, radiographic, gross pathologic, and histologic findings in 4 dogs with primary laryngeal neoplasia and 1 dog with secondary laryngeal neoplasia were reviewed. The clinical and radiographic findings were compared with those for proliferative inflammatory laryngeal conditions, since such conditions pose a problem in differential diagnosis. The most common clinical sign was hoarse bark or loss of voice, with subsequent onset of exertional dyspnea and cough.

Animals↗
PubMed1982

Prevalence of albinism in the South African negro.

Two hundred and six individuals (113 males and 93 females) affected with oculocutaneous albinism have been ascertained in 126 Black (South African Negro) families living in Soweto, Johannesburg. The prevalence is approximately 1/3 900 and the carrier rate about 1/32. Autosomal recessive inheritance has been demonstrated for the condition and consanguinity had been shown to be an important factor in the different prevalences found in the different ethnic groups represented in the study. The sex ratio of 1,21 is not significantly different from unity for a sample of this size.

Albinism↗
PubMed1982

Spondylohumerofemoral hypoplasia (giant cell chondrodysplasia): a neonatally lethal short-limbed skeletal displasia.

We report two sporadic cases with a previously undescribed skeletal dysplasia lethal in the neonatal period. The syndrome is characterized clinically by striking rhizomelic shortness of the limbs and radiographically by absence or hypoplasia of the humeri, hypoplastic vertebrae, absent fibulae and ossification in only the distal phalanges of the hands. Morphologic studies show hypocellular areas of growth plate cartilage containing occasional multinucleated giant cells.

Abnormalities, Multiple↗
PubMed1982

Is transferrin normal in idiopathic haemochromatosis?

Family studies were done to ascertain whether there is linkage between the transferrin locus and the HLA loci on chromosome 6. The findings in four families in which there was variation at the transferrin locus did not demonstrate any linkage, with 17 of the 30 offspring of heterozygous parents being recombinants and 13 non-recombinants. These results indicate that the HLA linked defect responsible for increased iron absorption in idiopathic haemochromatosis is not a consequence of any abnormality in the primary structure of transferrin.

Female↗
PubMed1982

Phophoglucomutase first locus polymorphism as revealed by isoelectric focusing in Southern Africa.

Eleven Southern African populations (representing European, Asian and Negroid populations) have been typed for the first locus phosphoglucomutase (PGM1) using isoelectric focusing (pH range 5.0-8.0) in acrylamide gels. The gene frequencies of the four common alleles at this locus in these populations were compared to those found previously in European and Negroid populations. Marked differences in gene frequencies were observed: Negroes have a lower PGM1(2-) compared with Caucasoids due to a lower PGM1(2-) frequency, Indians a relatively high PGM1(2) due to a higher frequency of the PGM1(2+) allele. The Afrikaans and Ashkenazim do not differ appreciably from their European counterparts. The appearances of the rarer PGM1(6) and PGM1(7) alleles on isoelectric focusing are described and some kinetic properties examined. The PGM2(2-1), or 'Atkinson' phenotype, can also be detected with this technique.

Africa, Southern↗
PubMed1981

Ataxia telangiectasia with evolution of monosomy 14 and emergence of Hodgkin's disease.

A young woman, with ataxia telangiectasia (AT) had a chromosomally abnormal T-lymphocyte clone detected at 23 years of age. This clone showed nonrandom loss of chromosome # 14, a karyotypic abnormality not previously described in AT. Eighteen months later, evolution of the monosomic clone was noted; the karyotype of this latter clone was 45,XX,-14,del(6) (q21). The patient died of Hodgkin's disease of mixed cellularity type, Stage IIIB, a few months later. A striking histological features of a lymph node biopsy was the presence of numerous epithelioid histiocytes. The patient's paternal first cousin also suffers from AT.

Adult↗
PubMed1980

A host of hypercholesterolaemic homozygotes in South Africa.

From 1972 to 1979 34 patients with homozygous familial hypercholesterolaemia were seen in one clinic in Johannesburg. All were Afrikaners and most lived in Transvaal Province. Their epidemiological, genetic, clinical, and biochemical characteristics were studied. The course of the disease varied considerably among the 34 patients, with no fewer than six surviving into their fourth or fifth decades. In some patients arterial atheroma was severe while cutaneotendinous xanthomas were slight and vice versa. Coronary heart disease was common but peripheral and cerebral arterial disease was rare. Another prominent finding was high concentrations of low-density lipoprotein cholesterol coupled with low high-density lipoprotein cholesterol values. The prevalences of homozygotes and heterozygotes with familial hypercholesterolaemia in Transvaal Afrikaners, calculated from this group of patients, were 1 in 30,000 and 1 in 100 respectively. These figures are the highest ever reported and may help to explain why South African whites have the highest death rate from coronary heart disease in the Western world.

Adolescent↗
PubMed1980

Chromosomal aberrations in occupation-associated progressive systemic sclerosis.

An occupational association between progressive systemic sclerosis (PSS) and workers in the goldmining industry in South Africa was first documented in 1957. We investigated the chromosomes of 18 goldminers suspected to be suffering from PSS. Eight patients were classified as definite cases of PSS, and a highly significant increase in unstable (Cu) cells and random aneuploidy was found in this group compared with control subjects (P < 0,001). Ten patients had some of the features of the disease, and in this group there was a significant increase in the number of Cu cells ( P < 0,05) and a highly significant increase in the number of aneuploid cells (P < 0,001). There was a significant increase in the number of sister chromatid exchanges per cell in the 6 patients screened. These findings are similar to those reported in PSS sufferers who have not had occupational exposure.

Adult↗
PubMed1980

Two years of mid-trimester amniocentesis in Johannesburg.

During a 2-year period 438 mid-trimester amniocenteses were performed on women at risk of producing an abnormal infant. The commonest indications were advanced maternal age (61% of cases), neural tube defects (18%) and Down syndrome (11%). A 92,5% follow-up revealed a spontaneous abortion rate of 3% (1,5% if abortions within 8 days of the procedure were considered). Premature birth occurred in 4,4% of cases, neonatal death or stillbirth in 0,7%, and birth defects which were detectable by amniocentesis in 2%. Abnormalities were detected in 4,9% of cases, so that 95,1% of the patients were reasured by the results obtained. No defects diagnosable by amniocentesis were missed.

Abortion, Incomplete↗