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Biomedical subjects

D Tait

Publications and source records attributed to D Tait.

At least 73 records · Page 4Linked to original sources

Functional neurological outcome in leukaemic children receiving repeated cranial irradiation.

Long-term outcome defined by educational or employment history has been recorded in a group of children with acute lymphoblastic leukaemia (ALL) who received cranial radiotherapy at some stage prior to TBI conditioned bone marrow transplant (BMT). Median follow-up in 24 survivors of 69 consecutive patients was 4 years and 2 months. Individual risk factors for poor functional outcome were considered, including calculations of biological effective radiation doses. There was no incidence of CNS treatment-related mortality. All survivors are in normal school or employment, although three who had CNS relapse are receiving remedial teaching. No individual risk factors could be identified but the worst outcome was seen in children who were of young age at the time of initial treatment, who suffered CNS relapse and who had received the highest total dose of cranial irradiation.

Adolescent↗

Bone marrow transplantation for primary refractory acute leukaemia.

Twenty-four patients with primary resistant acute leukaemia received bone marrow transplants (BMTs) from matched sibling, syngeneic, matched unrelated, or mismatched family donors as treatment for induction failure. Three (12.5%) patients are alive and well 2-10 years after transplantation. Four (16.7%) patients died of transplant-related complications early post-transplant and remission status could not be determined. Two patients did not achieve complete remission (CR) and died of cytomegalovirus pneumonitis 3 months post-transplant. One patient died of graft failure. CR was obtained in 17 of 20 (85%) evaluable patients after BMT. Ten of 17 (58.8%) patients achieving CR died of transplant-related complications 1-10 months post-transplant. Four of 17 (23.5%) patients who had achieved CR relapsed after transplant. We conclude that a high proportion of patients failing to achieve remission with aggressive conventional chemotherapy achieve CR with BMT and a small proportion become long-term survivors.

Adolescent↗

Use of liquid scintillation counting for fast determination of 89Sr and 90Sr in milk.

This paper describes a method of reproducibly recovering strontium (Sr) in 90.4% yield from 2-litre samples of raw milk in an analysis time of 5-8 h. All species which may interfere with the measurement of 89Sr and 90Sr are effectively removed; decontamination factors for Ca, Y, Ba and Cs were found to be adequate, and the role of other possible interferences is discussed. The Sr isolate was dissolved in scintillation cocktail prior to counting of 89Sr and 90Sr in a single measurement with a low-level liquid scintillation spectrometer. Scintillation spectra and counting efficiencies for 89Sr, 90Sr and 90Y have been established. A simple spectral stripping technique may thus be applied to calculate activities from the spectra of real samples. Results of analyses of five 2-1 milk samples containing known activities of 89Sr and 90Sr were respectively 87.7 +/- 3.5% and 90.4 +/- 3.0% (+/- 1 S.D.) of the activities added. A correction factor for the Sr yield was not applied. The detection limit of 0.014 Bq for 90Sr samples free of 89Sr implies that the method is also useful for routine monitoring of 90Sr.

Animals↗

Nosocomial adenovirus infection in a paediatric respiratory unit.

We report a nosocomial outbreak due to adenovirus in a paediatric respiratory unit serving a poor socio-economic community. Of 207 children admitted during an eight-month period, 24% were neonates; the median age of the remainder was 10 months. Thirty-two cases were found to be infected with adenovirus and of these 67% died. Nine were already infected with adenovirus when admitted. Twenty-three acquired the infection after admission, giving an incidence of nosocomial acquisition of 12% with a 91% mortality rate. All but one of the adenovirus infected children were being ventilated and had an endotracheal tube in place. Nosocomial spread was likely to have been from the hands of attendants, especially those manipulating suction catheters and endotracheal tube or ventilator connections. Risk factors for acquiring nosocomial infection were young age: all but two were < 1 year of age, and a relatively prolonged ward stay necessitated by the nature of the primary condition (pneumonia, bronchiolitis, laryngotracheo bronchitis, tetanus). The measures that were taken to control spread of the virus are described. Despite these, primary cases of adenovirus infection re-introduced the virus regularly over the study period. The genome analysis showed adenovirus types to be 7c2 and 7c.

Adenovirus Infections, Human↗

Prevalence and transmission of HTLV-I infection in Natal/KwaZulu.

A community-based seroprevalence survey for human T-cell lymphotropic virus type I (HTLV-I) was undertaken in the Ngwelezane district of Natal/KwaZulu. A total of 1,018 individuals was interviewed for risk factors and had blood drawn for serological examination. To exclude antibody cross-reactivity between anti-HTLV-I and anti-HTLV-II all Western blot HTLV-I-positive samples were further subjected to a Select HTLV test. For comparison, anonymous HIV testing was done. The areas of residence of patients with myelopathy associated with HTLV-I were also ascertained. The seroprevalence of HTLV-I was 2.6% (95% confidence interval (CI) 1.62-3.58). An age-related rise in HTLV-I seropositivity from 1.3% in the 15-24-year age group to 6.1% in the over 55-year-old group was noted. There was no significant association between HTLV-I antibody positivity and marital status, occupation, history of blood transfusion, scarification, age at first sexual experience and number of sexual partners. Anti-HIV-1 antibody testing revealed a positivity of 3.5% (95% CI 2.4-4.68) and the relative risk for co-infection with both HTLV-I and HIV-1 in the 15-24-year group was 1.16 (95% CI 1.08-1.24). The study also identified the first HTLV-II-seropositive case in the Natal/KwaZulu region. Up to December 1991, 90 cases of HTLV-I-associated myelopathy/tropical spastic paraparesis were seen at the Neurology Unit, Wentworth Hospital. The patients came from all parts of Natal, from Pongola in the north to Transkei in the south. The Natal/KwaZulu region is, therefore, an endemic HTLV-I area.

Adolescent↗

Selective avoidance of lymphatic radiotherapy in the conservative management of early breast cancer.

In view of the morbidity and potential mortality associated with routine post-operative lymph node radiotherapy in women with early stage breast cancer, an attempt has been made to select patients in whom radiotherapy can be withheld. Three hundred and forty-seven consecutive patients treated wide local excision plus or minus axillary surgery have been evaluated. Only 20% were subsequently given radiotherapy to regional nodes. Relapse in the axilla, the supraclavicular fossa or at both these sites have occurred in 16 patients so far, 12 of whom were successfully treated. Systemic relapse was seen in eight of these patients occurring with one exception before or within 3 months of node relapse. Only four have persisting symptoms as a result of nodal relapse. So far, a policy involving selective lymphatic radiotherapy in women treated for early breast cancer appears justified.

Axilla↗

'VEEP' in children with Hodgkin's disease--a regimen to decrease late sequelae.

In an attempt to decrease the risk of second malignancies and future infertility in children with Hodgkin's disease (HD) while retaining acceptable remission rates, an anthracycline based regimen containing no alkylating agent has been devised. VEEP contains vincristine, epirubicin, etoposide and prednisolone given at 3 weekly intervals. Forty-four patients, aged 2-15 years, have been treated: ten relapsed patients and 34 previously untreated with chemotherapy (including three relapsed stage I treated initially with radiotherapy). The median follow up for all patients is 25 months (range 6-52 months). The response rate in previously treated patients was 80% (95% CI 44-97%) and five remain alive in remission. The response rate in untreated patients was 88% (95% CI 72-97%) with 62% CR + CR(u) (uncertain/unconfirmed) (95% CI 44-77%). Of four patients who had a final response of CR(u) three have relapsed at 9, 16 and 38 months. Two of the children in CR have relapsed at 6 and 16 months. The relapse free rate at 3 years is 67% (95% CI 17-82%). In this pilot study the event free survival appears somewhat poorer than conventional combinations and further follow up is required to confirm the salvagability of relapsed patients.

Adolescent↗

Treatment planning for 131I-mIBG radiotherapy of neural crest tumours using 124I-mIBG positron emission tomography.

Patients designated to receive 131I-meta-iodobenzylguanadine (mIBG) for the treatment of neural crest tumours have been scanned with 124I-mIBG using the MUP-PET positron camera. Uptake was detected in tumour sites in lung, liver and abdomen. The tomographic images produced have allowed estimates to be made of the concentration of mIBG in both tumour and normal tissue. From these data it is possible to predict the radiation doses that would be achieved using therapy levels (up to 11 GBq) of 131I-mIBG. The levels of tumour uptake are between 0.5 and 2.0 kBq/g indicating that the radiation doses to tumour would be in the range 3 Gy to 7.5 Gy.

3-Iodobenzylguanidine↗

Results of a double blind placebo controlled study of ondansetron as an antiemetic during total body irradiation in patients undergoing bone marrow transplantation.

Total body irradiation (TBI) is a highly emetogenic component of the majority of conditioning regimens in use for bone marrow transplantation. Conventional antiemetic therapy fails to control nausea and vomiting induced by single fraction TBI in as many as 50% of patients. In a double blind study of 20 patients undergoing marrow transplantation, a single 8 mg ondansetron dose was compared with placebo given immediately prior to TBI. Our routine premedication of phenobarbitone and corticosteroid was also administered to all patients. All patients had received high dose melphalan the previous evening. Only 1 of the 10 patients in the ondansetron group experienced an emetic event compared with 5 of the 10 in the comparison group (p = 0.029). No significant adverse events were observed. Ondansetron appears to have extremely useful antiemetic activity during single fraction low dose rate TBI.

Adult↗

Rapid VAC high dose melphalan regimen, a novel chemotherapy approach in childhood soft tissue sarcomas.

Forty-three children with malignant soft tissue sarcomas (IRS Groups II-IV) were treated with rapid dose delivery chemotherapy protocol comprising six courses of vincristine, adriamycin and cyclophosphamide, given in most cases within 8 weeks (Rapid VAC). This was followed in 36 patients by high dose melphalan with autologous bone marrow rescue. Twenty-six patients also received irradiation to the site of primary tumour. The Rapid VAC regimen was well tolerated and largely administered as an out-patient. There was one toxic death which occurred 2 months after high dose melphalan due to a combination of infection and possible anthracycline cardiomyopathy. Stages were, (Intergroup Rhabdomyosarcoma Study (IRS) system) Group, Group II--four patients. Group III--27 patients and Group IV--12 patients; International Society of Paediatric Oncology (SIOP) staging, Stage I--11, Stage II--13, Stage III--7, Stage IV--12. Actuarial survival at 5 years for all stages is 57% and event free survival 44%. For patients with non-metastatic diseases, 62% and 53% respectively. This treatment strategy utilises the philosophy of rapid drug delivery with high dose consolidation and enables all chemotherapy to be finished within a 4 month period. In general, a conservative approach was applied to both radiation and surgery to minimise late sequelae related to these treatment modalities. Although the small number of high risk patients in this study limits conclusions regarding efficacy in these subgroups the overall results with this regimen appear to be comparable to that with other approaches.

Antineoplastic Combined Chemotherapy Protocols↗

High dose melphalan and total body irradiation with autologous marrow rescue in childhood acute lymphoblastic leukaemia after relapse.

High dose melphalan (HDM 110-140 mg/m2) and total body irradiation (TBI, 10.5 Gy, single fraction) followed by infusion of autologous bone marrow (ABMT) was evaluated for toxicity and efficacy in 24 children with acute lymphoblastic leukaemia (ALL) in second (CR2) or third remission (CR3). Marrow was purged with Campath 1 in six children (four were children in CR3). All children had engraftment with a median of 30 days (range 18-70 days) to neutrophil count greater than 0.5 x 10(9)/l. Four children (16%) died from toxicity 1-4 months after autograft, two from pneumonitis, one from an intracerebral haemorrhage and one from sepsis. Apart from fever and mucositis the procedure was well tolerated. Nine of 17 children treated in CR2 remain in complete remission 6-72 months after ABMT (median 25 months). Seven of these have a follow-up of greater than 12 months. Three of the seven children treated in CR3 are alive 17, 22 and 29 months post ABMT. Seven children relapsed within 10 months (median 4 months) of the autograft. Only one relapse has occurred beyond 10 months. HDM and TBI followed by ABMT is a relatively well tolerated regimen and may contribute to survival in children with relapsed ALL.

Adolescent↗

A double-blind comparative study of remoxipride and thioridazine in the acute phase of schizophrenia.

Sixty-one patients with acute schizophrenia received either remoxipride (75-375 mg daily) or thioridazine (150-750 mg daily) for 6 weeks. There was no statistically significant between-drug difference in improvement in mental state, as measured by the Brief Psychiatric Rating Scale, although the trend favoured thioridazine; global assessment of illness severity at the last rating also favoured thioridazine. Sedation, anticholinergic effects, autonomic dysfunction, and weight gain were significantly more common in patients receiving thioridazine. Both drugs produced few extrapyramidal effects, but both were associated with cardiovascular changes in two patients; neither drug produced significant abnormalities in laboratory tests.

Acute Disease↗

Technetium-99m HMPAO and SPECT in the assessment of blood flow in human lung tumours.

In order to assess the blood flow patterns through human lung tumours, 20 patients received 400-750 MBq 99TcmHMPAO intravenously 10 min before single photon emission computed tomography (SPECT). Ratios of uptake in the whole tumour relative to normal lung ranged from 0.35 to 1.53 (mean 1.01) with eight tumours showing less uptake than normal lung and ten showing greater uptake. In one patient the tumour was not distinguishable from surrounding lung and in another a large pleural effusion prevented evaluation. Tumour: lung ratios for central tumour regions ranged from 0 to 1.83 (mean 0.80) with 13 showing lower uptake than normal lung and five showing greater uptake. Duplicate scans were performed in eight patients demonstrating satisfactory reproducibility. This technique provides a simple and reproducible method for the assessment of tumour blood flow.

Adult↗

Benefits expected from simple conformal radiotherapy in the treatment of pelvic tumours.

In 20 patients with invasive bladder cancer suitable for radical radiotherapy, a simple conformal planning technique has been compared with conventional beam arrangements in terms of normal tissue sparing. The median treatment volume for the group was reduced from 2275 to 1416 cm3 by the introduction of conformal planning. More specifically, in 13/20 patients (65%) the percentage volume of rectum irradiated to 90% of the isocentric dose was reduced by more than 30%, although the extent of rectal sparing varied greatly between patients. Overall, conformal planning appeared to be less successful at reducing the volume of large and small bowel irradiated to high dose. However, the data suggest that considerable benefit can be expected for those patients most at risk of morbidity by virtue of high bowel volumes included within the treatment length. A randomised trial is now being set up to determine the clinical impact of this planning technique in terms of reduced bowel morbidity.

Humans↗

A double blind comparative study of remoxipride and thioridazine in the acute phase of schizophrenia.

This is the first comparative double blind study of remoxipride. Sixty-one patients with acute schizophrenia received either remoxipride (75-375 mg daily) or thioridazine (150-750 mg daily) for 6 weeks. There was no statistically significant between-drug difference in improvement in mental state, as measured by the Brief Psychiatric Rating Scale, although the trend favoured thioridazine; global assessment of illness severity at the last rating also favoured thioridazine. Sedation, anticholinergic effects, autonomic dysfunction and weight gain were significantly more common in patients receiving thioridazine. Both drugs produced few extrapyramidal effects, but both produced cardiovascular changes in two patients; neither drug produced significant abnormalities in laboratory tests.

Acute Disease↗