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Biomedical subjects

A Henderson

Publications and source records attributed to A Henderson.

At least 163 records · Page 9Linked to original sources
PubMed1985

Deletion in chromosome 11p associated with a hepatitis B integration site in hepatocellular carcinoma.

Hepatitis B virus (HBV), a virus with known carcinogenic potential, integrates into cellular DNA during long-term persistent infection in man. Hepatocellular carcinomas isolated from viral carriers often contain clonally propagated viral DNA integrations. As small chromosomal deletions are associated with several types of carcinomas, the occurrence of chromosomal deletions in association with HBV integration in hepatocellular carcinoma was studied. HBV integration was accompanied by a deletion of at least 13.5 kilobases of cellular sequences in a human hepatocellular carcinoma. The viral DNA integration and deletion of cellular sequences occurred on the short arm of chromosome 11 at location 11p13-11p14. The cellular sequences that were deleted at the site of HBV integration were lost from the tumor cells, leaving only a single copy of the remaining cellular allele.

Animals↗
PubMed1985

Cardiac effects of sodium stibogluconate.

Sodium stibogluconate although potentially cardiotoxic is the drug of choice for Kalaazar and cutaneous leishmaniasis due to Leishmania braziliensis. Increasing use of this drug in the British Army has necessitated a formal evaluation of its cardiac side-effects. Consequently a detailed study of the cardiac effects of sodium stibogluconate was undertaken in 22 male soldiers using for the first time modern non-invasive techniques. Intravenous sodium stibogluconate 600 mg daily for 10 days did not affect blood pressure, heart rate, left ventricular contractile function or rhythm. Electrocardiography showed a reversible reduction of T wave amplitude.

Adolescent↗
PubMed1985

RNA-mediated gene duplication: the rat preproinsulin I gene is a functional retroposon.

Rats and mice have two, equally expressed, nonallelic genes encoding preproinsulin (genes I and II). Cytological hybridization with metaphase chromosomes indicated that both genes reside on rat chromosome I but are approximately 100,000 kilobases apart. In mice the two genes reside on two different chromosomes. DNA sequence comparisons of the gene-flanking regions in rats and mice indicated that the preproinsulin gene I has lost one of the two introns present in gene II, is flanked by a long (41-base) direct repeat, and has a remnant of a polydeoxyadenylate acid tract preceding the downstream direct repeat. These structural features indicated that gene I was generated by an RNA-mediated duplication-transposition event involving a transcript of gene II which was initiated upstream from the normal capping site. Sequence divergence analysis indicated that the pair of the original gene and its retroposed, but functional, counterpart (which appeared about 35 million years ago) is maintained by strong negative selection operating primarily on the segments encoding the chains of the mature hormone, whereas the segments encoding the parts of the polypeptide that are eliminated during processing and also the introns and the flanking regions are evolving neutrally.

Animals↗
PubMed1985

Electrocardiography and echocardiography in patients with chest pain and mitral leaflet prolapse.

34 patients with catheter verified, haemodynamically trivial mitral leaflet prolapse with chest pain and normal coronary arteries were studied. Nineteen had no auscultatory signs of MLP despite clear catheter or echocardiographic evidence of prolapse. Infero-lateral repolarisation changes on the resting electrocardiogram were present in 29%. 50% had false positive exercise tests. M-mode echocardiography proved diagnostically disappointing but sector scans revealed mitral leaflet prolapse in 62%. The apical 4 chamber acoustic window was markedly superior to the parasternal long axis acoustic window.

Adult↗
PubMed1985

Frequency distribution and 95% range of a variety of commonly measured blood constituents in healthy Nepalese donors.

The most frequently measured biochemical and haematological blood constituents were assayed in 431 healthy Nepalese blood donors. As only 19 subjects were female analysis of their data was confined to calculation of the geometric mean. For the 412 males frequency distribution, geometric mean and 95% range were calculated for each constituent. Male and female male values were compared. It is hoped that 95% normal ranges might provide a better standard against which to compare data from Nepalese patients than the previously used reference ranges derived from ethnically different populations.

Adolescent↗
PubMed1984

Ferritin levels in patients with microcytic anaemia complicating pulmonary tuberculosis.

In a sample of 33 Nepali patients with microcytic, hypochromic anaemia complicating pulmonary tuberculosis, only 15% were iron deficient as judged by absence of stainable bone marrow iron. Individual ferritin levels in the iron deficient subjects were all within the normal range, although as a group their mean ferritin was significantly lower than in the non-iron deficient patients (104 micrograms/l v 349 micrograms/l p less than 0.05). It is suggested that in pulmonary tuberculosis ferritin synthesis is stimulated by the inflammatory process regardless of iron status and that the level of ferritin below which iron deficiency may be diagnosed is much higher than the accepted level of 15 micrograms/l.

Adolescent↗
PubMed1984

Tuberculosis in a developing country: experiences of the TB service at BMH, Dharan.

The notes of 3095 patients who attended the tuberculosis service of BMH Dharan between 1961 and 1982 were examined. Pulmonary tuberculosis accounted for 90% of cases. The overall rates of cure and default were 47% and 32% respectively. The reasons for default which mostly occurred within six months of starting treatment are examined. Changes in the policy of the service are suggested to make its operation more appropriate to its setting in a developing country.

Adolescent↗
PubMed1984

Typhoid masquerading as Japanese encephalitis.

We describe a variant of typhoid which was clinically indistinguishable from Japanese Encephalitis (JE). The strongly encephalitic presentation led to a potentially serious delay in starting specific antibiotic therapy. Awareness of the usual form of typhoid is of great importance to Army doctors because of the presence of British soldiers and families in the Dharan area of southern Nepal where both typhoid and JE are endemic.

Adult↗
PubMed1984

Severe tetanus complicating an open femoral fracture successfully managed using intrathecal human tetanus immunoglobulin and external fixation.

We report here a case of severe tetanus, complicating a compound fracture of the femur, successfully managed without intensive care facilities, using intravenous sedation and intrathecal Human Tetanus Immunoglobulin (HTI). Substitution of conventional traction (Transtibial Steinman Pin and Thomas Splint) for a Day Frame External Fixation Device (EFD) provided excellent fixation and stability of the fracture in spite of severe tetanic spasms.

Adolescent↗
PubMed1984

Immunisation against Japanese encephalitis in Nepal: experience of 1152 subjects.

During the summer of 1983, 1152 subjects were immunized against Japanese Encephalitis at BMH Dharan. This was the first use of the BIKEN killed lyophilised vaccine in the British Army. Three doses of 1 ml (0.5 ml for children under 3 years) given 10 days apart produced a protective neutralizing antibody response (titre more than 1:10) in almost 90% of subjects. Two doses of vaccine however seemed inadequate in that less than 40% of subjects seroconverted. Side-effects were minimal and trivial. Studies of neutralizing antibodies before vaccination showed up to 30% of Nepalese subjects tested were already immune due to previous inapparent infection while all but one of the British Nationals were fully susceptible.

Adult↗
PubMed1983

Lack of site specific recombination of exogenous DNA in mouse L cells.

Plasmids were constructed containing the HSV thymidine kinase gene and two copies of X. borealis 5S rDNA. Mouse L TK- cells were transformed with these DNAs, with selection for the TK+ gene. Transformed cells were then analyzed by Southern blot hybridization and hybridization in situ to determine whether integration of the exogenous DNA occurred at regions of chromosomal homology i.e., at the 5S rDNA regions. Four cell lines were analyzed by Southern blots. Differences in restriction endonuclease specificity strongly suggested that integration was at a different site in each cell line. Two cell lines were further analyzed by hybridization in situ; each showed a single integration site, both different from each other and different from the mouse L cell 5S rDNA sites. Therefore, the presence of two copies of the 5S rDNA gene in the DNA introduced by gene transfer and approximately 300-350 copies of the mouse 5S rDNA gene was not sufficient in these experiments to produce homologous integration into a specific site.

Animals↗
PubMed1983

Chromosome site for Epstein-Barr virus DNA in a Burkitt tumor cell line and in lymphocytes growth-transformed in vitro.

The Epstein-Barr virus (EBV) genome stably persists in latently infected Burkitt tumor cells and growth-transformed B lymphocytes. These cells usually contain multiple copies of episomal viral DNA. Cytological hybridization of recombinant viral DNA fragments to metaphase chromosomes of two latently infected cell lines demonstrates that viral DNA localizes to both chromatids of one homologue of chromosome 1 in Namalwa, a Burkitt tumor cell line, and to both chromatids of one homologue of chromosome 4 in IB4, a cell line with transformed growth properties in vitro. The site of chromosome association remains stable in a clone of IB4 cells. Probes from five separate regions of the EBV genome hybridize to the same chromosome regions. A previously undescribed achromatic site is identified within the region of EBV chromosome cytological hybridization. These observations suggest that most or all of the EBV genome is integrated into the chromosomal DNA of Namalwa and IB4 cells. Although the chromosomal sites of EBV DNA association are among those regions with homology to the EBV IR3 repeated DNA sequence, EBV IR3 did not mediate recombination between EBV and chromosomal DNA.

Burkitt Lymphoma↗
PubMed1983

Prognostic implications of creatine phosphokinase levels after acute myocardial infarction--a study of low risk patients.

To determine the prognostic value of Creatine Phosphokinase (CPK) levels after acute myocardial infarction in patients thought to be at low risk of death or major complications, 94 consecutive patients with definite myocardial infarction were divided into two groups according to peak CPK levels. Group I contained 23 patients with a peak CPK of less than 1000 units and Group II contained 71 patients with a peak CPK level of greater than 1000. They were followed for six months or to death. A CPK of greater than 1000 was significantly associated with left ventricular failure, major arrhythmias and late death and seemed therefore to have value as an indicator of poor prognosis.

Creatine Kinase↗
PubMed1983

Encephalitis in Nepal: the visitation of the goddess of the forest.

Examination of hospital records from BMH Dharan and the large Nepalese hospital at Biratnagar has revealed a worrying trend in the incidence of acute encephalitis in the area of the British Military Cantonment at Dharan. The weight of available evidence strongly favours Japanese Encephalitis Virus (JEV) as the aetiological agent. Serological studies from healthy Nepalese from the Dharan area and animals from the Cantonment farm indicate that intense transmission of JEV occurs within the Cantonment area. Japanese Encephalitis (JE) must now be regarded as a serious threat to British Military personnel and dependants living in or visiting Nepal. Protective measures, particularly active immunisation are discussed.

Adolescent↗