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Biomedical subjects

C R Lewis

Publications and source records attributed to C R Lewis.

At least 19 recordsLinked to original sources
PubMed2000

B-cell stimulation and prolonged immune deficiency are risk factors for non-Hodgkin's lymphoma in people with AIDS.

OBJECTIVES: To identify risk factors for non-Hodgkin's lymphoma (NHL) in people with HIV infection. DESIGN AND SETTING: Case-control study in Sydney, Australia. PARTICIPANTS AND METHODS: Two hundred and nineteen patients with AIDS-related NHL were compared with 219 HIV-infected controls without NHL, matched for CD4 positive cell count and date of specimen collection. Data on demographic, infectious, treatment-related and immunological factors were abstracted by medical record review. The association between demographic factors, sexually transmissible diseases, HIV-related opportunistic infections, anti-viral therapy, duration of immune deficiency and indices of immune stimulation and risk of NHL were derived for these groups. RESULTS: In a multivariate model, there were two independent groups of predictors of NHL risk. The first was duration of immunodeficiency, as measured by longer time since seroconversion (P for trend 0.008), and lower CD4 positive cell count 1 year prior to the time of NHL diagnosis (P for trend 0.009). The second predictor was B-cell stimulation, as indicated by higher serum globulin (a surrogate marker for serum immunoglobulin, P for trend 0.044) and HIV p24 antigenaemia [odds ratio (OR) for p24 positivity, 1.82; 95% confidence interval (CI), 1.15-2.88]. Indices of B-cell stimulation preceded the diagnosis of NHL by several years. Factors not related to NHL risk included clinical indices of Epstein-Barr virus infection and receipt of individual nucleoside analogue antiretroviral agents. Combination therapy with these agents was associated with a non-significant reduction in NHL risk (OR, 0.68; 95% CI, 0.39-1.18). CONCLUSIONS: Markers of long-standing immune deficiency and B-cell stimulation were associated with an increased risk of developing NHL. Unless the strongest risk factor for NHL, immune deficiency, can be reversed, NHL is likely to become proportionately more important as a cause of morbidity and mortality in people with HIV infection.

Adult↗
PubMed1996

Mature results of a randomized trial of two doses of cisplatin for the treatment of ovarian cancer. Scottish Gynecology Cancer Trials Group.

PURPOSE: In 1992, we reported the first results of a randomized study in ovarian cancer, comprising two doses of cisplatin and indicated a significant difference (P = .0008) in median survival. Four years later, we now describe the results of this trial. PATIENTS AND METHODS: After a median follow-up of 4 years and 9 months, 115 of 159 cases of advanced ovarian cancer, originally randomized to receive six cycles of cyclophosphamide 750 mg/m2 and either a high dose (HD) of 100 mg/m2 cisplatin or a low dose (LD) of 50 mg/m2 (LD) cisplatin, have now died. RESULTS: The overall survival for HD and LD patients is 32.4% and 26.6%, respectively, and the overall relative death rate is 0.68 (P = .043). This represents a reduction in overall benefit with longer follow-up compared with the first 2 years (relative death rate of 0.52). Toxicity, particularly neurotoxicity, is still evident in the fourth year (10/31 on HD compared with 1/24 on LD). CONCLUSION: Our recommended dose of cisplatin in combination schedule is therefore 75 mg/m2, representing the optimal balance between efficacy and toxicity.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1993

Serum concentrations of oestradiol and progesterone and frequency of sexual behaviour during the normal oestrous cycle in the snow leopard (Panthera uncia).

Serum oestradiol and progesterone concentrations were measured at weekly intervals for six months, and correlated with daily behavioural observations in two adult female snow leopards (Panthera uncia). Three oestradiol peaks (> 21 pg ml-1; interval 3.6 weeks) were identified in a snow leopardess housed alone (two more were probably missed because of the weekly sampling schedule), and three oestradiol peaks were identified in a snow leopardess housed with a male as a breeding pair (interval 6 weeks). Daily frequencies of feline reproductive behaviour averaged 1.77 observations per observation period during weeks of high oestradiol and 0.62 during weeks of low oestradiol. Progesterone concentrations did not rise above baseline values (< 2 ng ml-1) in the isolated animal, but 6 weeks of high progesterone concentrations (4.9-38.8 ng ml-1) was recorded in the paired snow leopardess following mating. No offspring were produced. Snow leopards were observed daily for an additional 4.5 years. Sexual behaviour peaks could be clearly identified from December through April, and average daily sexual behaviour scores were higher during these months than during the rest of the year. Intervals between sexual behaviour peaks for the isolated snow leopardess averaged 3.03 weeks. The sexual behaviour of the paired snow leopards decreased for 8-9 weeks following mating when no offspring were produced, and decreased for 13 weeks in one year when a single cub was born.

Animals↗
PubMed1992

Randomised study of two doses of cisplatin with cyclophosphamide in epithelial ovarian cancer.

Cisplatin is generally accepted to be the most active cytotoxic agent for the treatment of ovarian cancer but the optimum dose remains unclear. We have performed a randomised trial to assess the importance of cisplatin dose in the treatment of advanced epithelial ovarian cancer. Patients were randomly assigned treatment with 50 mg/m2 (low dose) or 100 mg/m2 (high dose) cisplatin plus 750 mg/m2 cyclophosphamide, for a maximum of six cycles with intervals of 3 weeks. We planned to recruit 300 patients, but an interim analysis on the first 165 indicated a highly significant survival difference (p = 0.0008). Recruitment was therefore stopped and the trial patients were followed-up for 12 months longer. The relative progression rate (high-dose/low-dose) after 12 months' extra follow-up was 0.55 (95% confidence interval 0.37-0.81, p = 0.003) and the relative death rate 0.53 (0.34-0.81, p = 0.003). Overall median survival was 69 weeks in the low-dose group and 114 weeks in the high-dose group. Residual disease extent before chemotherapy had an important influence--patients with lesions of less than 2 cm did best; if given high-dose cisplatin their median survival was 3 years. 56 low-dose and 45 high-dose patients completed six cycles of chemotherapy; 15 and 9 patients, respectively, were withdrawn early because of progressive disease and treatment was stopped in 6 and 25, respectively, because of unacceptable side-effects or patient refusal. Toxic effects were significantly greater in the high-dose group, especially those on the nervous system and ears, alopecia, vomiting, and anaemia. Although the higher dose of cisplatin clearly leads to better results in terms of survival, its overall clinical benefit in the management of ovarian cancer will depend on further improvements in measures to alleviate toxic effects.

Adult↗
PubMed1992

An independent evaluation of the potential clinical usefulness of proposed CA-125 indices previously shown to be of prognostic significance in epithelial ovarian cancer.

CA-125 levels were assessed prior to each of the first three cycles of chemotherapy, in 81 patients with epithelial ovarian cancer receiving first-line chemotherapy. All patients have at least 1 year's follow-up. Thirty-nine patients (48%) have progressed clinically or have died within 1 year of treatment (treatment 'failures'). Three CA-125 indices previously shown to be of prognostic value are assessed for their ability to pick-out these 'failures'. When the indices examined are modified to obtain a specificity for picking out failures just exceeding 90%, the maximum sensitivity obtained was 46%. The use of CA-125 for clinical decision making in ovarian cancer requires further investigation to determine and validate a prognostic index with acceptable sensitivity and specificity, and to determine the clinical impact of treatment decisions made using such an index.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1992

The changing role of surgery in metastatic non-seminomatous germ cell tumour.

In the last 2 years (1989-1990) we have treated a total of 53 patients with metastatic nonseminomatous germ cell tumours (teratoma). In ten cases surgery to remove residual abdominal masses was required on completion of chemotherapy and normalisation of tumour markers (HCG and AFP). In a further three patients with large intra-abdominal masses and little or no other sites of disease surgery was performed as a therapeutic intervention, in the context of plateauing or rising tumour markers despite intensive chemotherapy. In all three, this approach resulted in a rapid fall in tumour markers, and following further chemotherapy all three remain disease free at 7, 12 and 25 months. For this small sub-group of patient failing to respond to chemotherapy who have resectable lesions, interventional surgery should be considered as part of a combined approach to treatment.

Adult↗
PubMed1991

BOP/VIP--a new platinum-intensive chemotherapy regimen for poor prognosis germ cell tumours.

Ninety-one patients with poor prognosis non-seminomatous germ cell tumours (NSGCT) were treated with an initial intensive chemotherapy schedule. Suitable patients fulfilled one or more of the following criteria: lymph node metastases greater than 10 cm diameter; liver, brain or bone metastases; serum HCG level greater than 50,000 IU/L; and extragonadal primary tumours. Treatment consisted of 3 cycles of bleomycin, vincristine and cisplatin (BOP) administered at 10 day intervals, followed by 3 cycles of etoposide, ifosfamide and cisplatin (VIP) at 21 day intervals. A total of 64 patients (70%) achieved a complete remission. This comprised 46 patients who received BOP/VIP only, and 18 patients who received additional chemotherapy after BOP/VIP. Of these 64 patients, 51 underwent complete surgical resection of residual masses, including 11 in whom there was evidence of teratoma with cellular atypia or non-germ cell cancer in the resected tissue. A further 9 patients had persisting unresected radiological masses in the presence of marker complete remission. The overall response rate was 80%. Currently 57 patients (63%) remain alive and free from disease progression. The median follow-up period is 90 weeks (range 24-206 weeks), with a 2 yr actuarial progression-free survival of 66% (95% c.i. 55-77%). Major toxicity was myelosuppression, occurring during the VIP arm of therapy, with a median nadir WBC of 1.1 x 10(9)/L and median platelet count of 51 x 10(9)/L. Other toxicity included peripheral neuropathy (WHO Grade 2 and 3 in 22%). We conclude that treatment results with the BOP/VIP schedule in this poor prognosis patient group are at least comparable with other schedules, and toxicity is manageable.(ABSTRACT TRUNCATED AT 250 WORDS)

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

Serum concentrations of oestradiol and progesterone, and sexual behaviour during the normal oestrous cycle in the leopard (Panthera pardus).

Three mature nulliparous female leopards were studied for 5 years. During three separate 6-month periods serum oestradiol and progesterone concentrations were measured at weekly intervals. Oestradiol was elevated over 21 pg/ml for 54 weeks during these 3 periods, and 36 oestradiol peaks (65.8 +/- 6.3 pg/ml (mean +/- s.e.m.), range 21-172 pg/ml) were identified. Daily frequency of feline reproductive behaviours averaged over each week increased from 1.9 +/- 0.2 (n = 93) during weeks with low serum oestradiol concentrations (less than 21 pg/ml) to 5.3 +/- 0.6 (n = 54) during weeks when serum oestradiol concentrations (greater than 21 pg/ml) were high. Increased serum progesterone concentrations (13-98 n/gml) were observed on 5 occasions in 2 leopards housed together. These presumptive luteal phases lasted from 1 to 5 weeks. Baseline progesterone values were 1.6 +/- 0.4 ng/ml (n = 131). No progesterone increments were observed in isolated animals, and serum concentrations remained at baseline levels. These limited observations suggest that female leopards do not require intromission to induce ovulation and luteal function. The average interval between oestradiol peaks for cycles with no progesterone increment was 3.4 weeks (range 1-6 weeks). The interval for the 3 complete cycles associated with elevated progesterone concentrations was 7.3 weeks. Analysis of sexual behaviours over the 5-year study period revealed no evidence of seasonality in these captive leopards.

Animals↗
PubMed1987

Pure red cell hypoplasia secondary to isoniazid.

We describe a 77 year old man who developed pure red cell aplasia while receiving antituberculous therapy including isoniazid. Prompt recovery occurred following cessation of isoniazid. In this paper we also review previously described case reports of isoniazid-induced pure red cell aplasia.

Aged↗