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Biomedical subjects

D Todd

Publications and source records attributed to D Todd.

At least 163 records · Page 9Linked to original sources
PubMed1986

Characterisation of an antiserum and development of an ELISA for glutathione peroxidase.

Sheep red blood cells were fractionated by ion exchange and gel filtration chromatography to yield glutathione peroxidase approximately 99% pure. An antiserum against glutathione peroxidase was raised in the rabbit. The antiserum has been shown to cross-react with both bovine and human glutathione peroxidase by double diffusion. An enzyme linked immunosorbent assay has been developed for glutathione peroxidase which detected 6.15 X 10(-5) IU of the enzyme. The antiserum has also been shown to be effective in the detection of glutathione peroxidase immobolised on strips of nitrocellulose, subsequent to sodium dodecyl sulphate polyacrylamide gel electrophoresis, by second antibody conjugate. Avidin-biotin was also used to detect nitrocellulose immobolised enzyme. These techniques provide an alternative highly sensitive and specific means of assaying glutathione peroxidase which is not dependent on the lability of enzymatic activity nor the chemical specificity of the assay.

Animals↗
PubMed1986

Intracerebral chloromas. Report of a case and review of the literature.

We report a patient with large intracerebral chloromas while in systemic remission from acute myelogenous leukemia. A favourable outcome resulted from surgical debulking and radiotherapy. Review of other reported cases in the literature showed a uniform female occurrence. We believe that intracerebral chloromas represent reactivation of sanctuary deposits in the central nervous system. The treatment of intracerebral chloroma is discussed.

Adult↗
PubMed1986

Organization of the zeta-alpha genes in Chinese.

Analysis of alpha and zeta genes in 101 healthy normals and hospitalized patients with non-haematological diseases revealed a 3% incidence of alpha thalassaemia in the local Chinese population of Hong Kong. Triple alpha genes were found in only one person while triple zeta genes were more prevalent, occurring in 13 subjects. Studies of 28 unselected patients with Hb H disease indicated a predominance of the rightward alpha gene deletion. The extent of alpha gene deletion in homozygous alpha thalassaemia 1 was at least 18.1 kb, beginning from the BamH I site 3' to the zeta 1 gene and includes the psi alpha, alpha 2 and alpha 1 genes. Nineteen of the 20 chromosomes bearing the alpha thalassaemia 1 deletion had identical zeta-intergenic hypervariable region suggesting a common origin of this mutation. The co-inheritance of alpha thalassaemia in beta thalassaemia subjects was 8%, but did not ameliorate the clinical features of those with homozygous beta thalassaemia.

China↗
PubMed1986

Spinal cord compression in multiple myeloma: who gets it?

Of 97 Chinese patients with multiple myeloma seen over a 12-year period, 23.7% were found to have cauda equina or spinal cord compression (SCC). Predictive features for SCC include paraprotein type, hemoglobin level, and the extent of bone lesion at initial hematological diagnosis. A discriminant function derived from this analysis can be used to predict the likelihood of SCC with 79% accuracy. It is postulated that when the cortex is more involved than the medulla in a vertebra, it will predispose to SCC while hemopoiesis is relatively preserved. Our patients presented late with advanced neurological deficit so that treatment was unsatisfactory. It is emphasised that early recognition of back pain and neurological symptoms is essential, as any delay would jeopardize the chance of neurological recovery.

Adult↗
PubMed1986

Antenatal and intrapartum events influencing outcome in very low birth-weight infants.

The influence of antenatal and intrapartum events and the route of delivery on Apgar scores and short-term outcome was studied in 359 singleton very low birth-weight infants who were resuscitated adequately at birth and had no lethal congenital anomalies. When stratified according to gestation the occurrence of antepartum haemorrhage, pregnancy-induced hypertension and amnionitis had no influence on the outcome while cord prolapse in infants less than 26 weeks resulted in 100% mortality. Prolonged rupture of membranes significantly improved the chances of their survival. The route of delivery did not influence survival, but greater numbers of babies between 27 and 30 weeks delivered by the breech had lower Apgar scores both at 1 and 5 minutes. Survival was dependent on gestational age and the condition at birth among this group of very low birth-weight infants.

Apgar Score↗
PubMed1986

Immunohistological subtypes of non-Hodgkin's lymphoma in Hong Kong Chinese.

One hundred and four unselected cases of non-Hodgkin's lymphoma (NHL) in adult Chinese patients in Hong Kong were typed, using monoclonal and conventional antibodies, by immunoenzymatic labelling methods on cryostat sections or cell smears. The total included 69 cases (66%) of B-cell and 26 (25%) of T-cell tumours. The diffuse large cell (centroblastic or immunoblastic) types formed the largest proportion (44.9%) of B lymphomas. Of 26 cases of T-cell lymphoma 25 were of peripheral type; of these 25, the most frequent subtype (42.3%) was the immunoblastic lymphadenopathy-like lesion. Although there were 9 pleomorphic T-cell lymphomas, none of the patients presented with the adult T-cell leukemia/lymphoma syndrome. The incidence of T-cell lymphomas in our population is not markedly higher than that of western countries, but there are some interesting differences in the types of T-cell lymphomas that are commonly seen.

Adult↗
PubMed1986

AIDS in a Hong Kong Chinese.

A young Hong Kong Chinese male patient with fever of unknown origin is presented. The diagnosis of acquired immunodeficiency syndrome was made only 5 months after the onset of his illness. The lack of awareness of the syndrome might account for the delay in the diagnosis. The legal attitude towards homosexuality might have an adverse effect on epidemiological studies of AIDS in Hong Kong.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Vision therapy as a treatment for motion sickness.

A case of visually-induced motion sickness (VIMS) is presented. The patient underwent a program of dynamic adaptive vision therapy which relieved her symptoms of motion sickness. Symptoms of VIMS may include photophobia, an inability to read in a moving auto, and nausea, dizziness, headache, eye strain and anxiety following provocative visual stimuli. The neural mismatch theory is discussed.

Adult↗
PubMed1985

Restriction endonuclease analysis of Aujeszky's disease (pseudorabies) virus DNA: comparison of Northern Ireland isolates and isolates from other countries.

Aujeszky's disease (AD; pseudorabies) viruses isolated in Northern Ireland over a 20 year period were compared with isolates from other parts of the world using restriction endonuclease analysis of virus DNA. When the numbers of Bam H1, Kpn 1 and Sal 1 restriction sites were considered, pathogenic Northern Ireland isolates resembled viruses isolated in England, Hungary and the U.S.A. and could be differentiated from viruses isolated in Denmark, Belgium and the Netherlands. The avirulent Northern Ireland isolate NIA4 and the Bartha vaccine strain were very similar to each other and could be distinguished from pathogenic isolates. While almost all the pathogenic viruses isolated in Northern Ireland from 1963 to 1983 appeared to possess the same number of restriction sites none of the viruses, even those made at the same farm during one outbreak of infection, were identical. The differences were confined to variation in the sizes of certain fragments which map in "variable" regions of the genome.

Base Sequence↗
PubMed1985

The rapid detection of Aujeszky's disease virus in pigs by direct immunoperoxidase labelling.

Direct immunoperoxidase labelling on impression smears of brain and pharynx was compared with virus isolation and direct immunofluorescence for the detection of Aujeszky's disease virus in experimentally-infected pigs. Immunoperoxidase labelling was as sensitive as immunofluorescence and more sensitive than virus isolation for tissue that had been stored at room temperature (approximately 20 degrees C) for up to 144 h.

Animals↗
PubMed1985

Homozygous alpha-thalassaemia: clinical presentation, diagnosis and management. A review of 46 cases.

Forty-six hydropic infants with homozygous alpha-thalassaemia born during a period of 10 years have been reviewed. The incidence was 1:1550 total births, and accounted for 81% of all non-immune hydrops. The male to female ratio was 1:1.4. There was increased incidence of anaemia, pregnancy induced hypertension, antepartum haemorrhage, malpresentation, prematurity, fetal distress, difficult vaginal delivery, caesarean section, retained placenta, postpartum haemorrhage and congenital abnormalities. Antenatal diagnosis by DNA hybridization with subsequent abortion of the affected fetuses is the best method to decrease maternal morbidity and to reduce the incidence of hydrops fetalis in couples at risk. For those with no previous history, but with early onset hypertension and/or polyhydramnios, sonography is useful in making an earlier diagnosis, and in reducing avoidable morbidity, because DNA analysis can be done before caesarean section and aggressive neonatal management is instituted.

Adolescent↗
PubMed1985

Herbal tea induced hepatic veno-occlusive disease: quantification of toxic alkaloid exposure in adults.

Four young Chinese women took daily doses of an unidentified 'Indian' herbal tea as treatment for psoriasis. Three (one of whom died), developed ascites, hepatomegaly and biochemical abnormalities within 19-45 days. The fourth patient discontinued herbal tea after 21 days when she developed a skin rash. Two patients had portal hypertension, while all had liver histology showing features of veno-occlusive disease. Pyrrolizidine alkaloids were identified spectrophotometrically in the brewed tea, and in the chopped leaves of the herbal mixture; the mean dose in the tea prepared for consumption being 12 mg/day of alkaloid base and 18 mg/day of N-oxide. The mean cumulative dose of alkaloids (base + N-oxide) before onset of symptoms (three patients), was estimated to be 18 mg/kg. In the asymptomatic patient with histological liver disease only, the corresponding dose was 15 mg/kg. These cases thus provide some measure of pyrrolizidine alkaloid toxicity in adults.

Adult↗
PubMed1985

Hydrops fetalis due to an unusual form of Hb H disease.

The occurrence of Hb H hydrops fetalis is reported for the first time. The mother has zeta-alpha thalassemia 1 (zeta zeta alpha alpha/----) and the father has non-deletion alpha thalassemia [zeta zeta alpha alpha/zeta zeta (alpha alpha)T]. The complete deletion of the zeta alpha cluster on one chromosome was confirmed by quantitation of alpha and zeta gene numbers, the normal alpha and zeta gene patterns arising from the remaining normal chromosome, and the decreased alpha/beta globin chain ratio of 0.57. The non-deletion alpha thalassemia defect could only be identified by the imbalanced alpha/beta globin chain ratio of 0.65 in the presence of normal gene numbers and patterns. The newborn was markedly anemic, unlike those with classical Hb H disease, because the non-deletion alpha thalassemia defect is more severe than alpha thalassemia 2. The decreased zeta genes during fetal life might have additional deleterious effects. In this family, the distinct BamHI restriction fragment length polymorphism in the hypervariable region of the zeta genes may be used for future prenatal diagnosis.

DNA Restriction Enzymes↗
PubMed1984

BamH I polymorphism in the Chinese: its potential usefulness in prenatal diagnosis of beta thalassaemia.

The prevalence of the BamH I site 3' to the beta globin gene in Chinese people was determined in 123 normal subjects, 40 patients with heterozygous beta thalassaemia, and 25 patients with homozygous beta thalassaemia. The site was present in 71.1% and absent in 28.9% of the chromosomes carrying normal beta genes. All 25 patients with beta thalassaemia major had the site. This BamH I polymorphism may be used for prenatal diagnosis in about 29% of the pregnancies at risk.

Adult↗
PubMed1984

Clinico-pathological features of malignant lymphomas in 294 Hong Kong Chinese patients, retrospective study covering an eight-year period.

The clinical records and histological material from 294 adult Chinese patients with malignant lymphoma were examined. These patients were first seen at the Queen Mary Hospital, Hong Kong, during the 8-year period 1975-82. There were 27 patients (9.2%) with Hodgkin's disease (HD) and 267 with non-Hodgkin's lymphoma (NHL). The median age at presentation was younger for HD (45 years) and the male: female ratio was higher (2:1) than the corresponding figures for NHL of 51 years and 1.4:1. In 76 patients (28.5% of NHL), the disease was thought to have originated in an extra-nodal site, 48 of these cases being gastrointestinal lymphomas. It was possible to reclassify 234 NHL according to the Rappaport and Kiel classifications, and the Working Formulation (WF) proposed by the US National Cancer Institute Study; for HD, the Rye classification was used in 26 cases where suitable material was available. Nodular/follicular lymphomas made up 17.1% of nodal NHL and 5.3% of extra-nodal NHL. The "histiocytic" (Rappaport) or large-cell (WF) subtype was the commonest amongst diffuse NHL. There were only four cases of Burkitt's lymphoma. For HD, the nodular sclerosing subtype was commonest in females (5 out of 8 cases) and for males, the commonest was mixed cellularity (10 out of 18 cases). Of patients with nodal NHL 64.7%, presented with Stage IV disease. For HD, there were about equal numbers of patients presenting with Stage II and Stage IV disease (10 and 9 respectively). The low incidence of Hodgkin's disease and of follicular lymphomas is comparable to figures from other "oriental" countries such as Japan.

Adolescent↗