PubMed Health⌕ Search

Biomedical subjects

V Nicolson

Publications and source records attributed to V Nicolson.

16 recordsLinked to original sources
PubMed2006

Assessment of reproductive status in male echidnas.

This study reports the development and application of techniques to assess the reproductive status of male echidnas. The pattern of testosterone secretion over a 24-h period in five echidnas was documented. Testosterone secretion after injection i.m. of either 1000 IU hCG (n=4) or 4 microg GnRH agonist (n=6) was determined to establish whether this could be used as a practical index of the prevailing steroidogenic capacity of the testes. hCG (1000 IU) was also used to assess seasonal changes in testosterone secretion in six echidnas over a 13-month period. Seasonal changes in testicular volume were examined by transabdominal ultrasonography. Electroejaculation was attempted to monitor seasonal changes in sperm production, which was also determined by spermatorrhea. There was no apparent diurnal pattern of testosterone secretion in echidnas and circulating concentrations of testosterone remained relatively low (maximum 1.2 ng/mL) and stable over 24h. Injection of hCG resulted in an increase (P<0.01; n=4) in testosterone concentration with a peak (2.9+/-0.3 ng/mL) approximately 4h after injection. GnRH also induced an increase (P<0.01; n=6) in circulating testosterone that was apparent after 1h (2.6+/-0.3 ng/mL) and concentrations remained elevated (3.4+/-0.3 ng/mL) for up to 8h after injection. Seasonal changes in testosterone secretion determined after injection of hCG, increased (P=0.03; n=6) from late-autumn, peaked in late-winter, and decreased by early-spring. Testicular volume followed a similar seasonal pattern (P<0.01; n=6) with an increase from late-autumn, peak in winter and a decline in mid-spring. There was no seasonal change in live weight. Electroejaculation was attempted throughout two breeding seasons but no semen was obtained. Spermatorrhoea in the echidna was described for the first time and was subsequently used to assess seasonal sperm production. Spermatozoa were found in the urine from June to September. This study has demonstrated that exogenous hormones can be used to obtain an index of the prevailing steroidogenic capacity of the testes in echidnas, which is not apparent with repetitive non-stimulated samples over 24 h. The assessment of testosterone secretion after injection of trophic hormones provides a valuable and practical procedure for the assessment of reproductive status. Testicular ultrasonography and spermatorrhea are useful in assessing reproductive status and in this study were successfully used to determine seasonal reproduction in captive echidnas.

Animals↗
PubMed2000

Studies of the oestrous cycle, oestrus and pregnancy in the koala (Phascolarctos cinereus).

As an integral part of the development of an artificial insemination programme in the captive koala, female reproductive physiology and behaviour were studied. The oestrous cycle in non-mated and mated koalas was characterized by means of behavioural oestrus, morphology of external genitalia and changes in the peripheral plasma concentrations of oestradiol and progestogen. The mean (+/- SEM) duration of the non-mated oestrous cycle and duration of oestrus in 12 koalas was 32.9 +/- 1.1 (n = 22) and 10.3 +/- 0.9 (n = 24) days, respectively. Although the commencement of oestrous behaviour was associated with increasing or high concentrations of oestradiol, there were no consistent changes in the morphology or appearance of the clitoris, pericloacal region, pouch or mammary teats that could be used to characterize the non-mated cycle. As progestogen concentrations remained at basal values throughout the interoestrous period, non-mated cycles were considered non-luteal and presumed anovulatory. After mating of the 12 koalas, six females gave birth with a mean (+/- SEM) gestation of 34.8 +/- 0.3 days, whereas the remaining six non-parturient females returned to oestrus 49.5 +/- 1. 0 days later. After mating, oestrous behaviour ceased and the progestogen profile showed a significant increase in both pregnant and non-parturient females, indicating that a luteal phase had been induced by the physical act of mating. Progestogen concentrations throughout the luteal phase of the pregnant females were significantly higher than those of non-parturient females. Parturition was associated with a decreasing concentration of progestogen, which was increased above that of basal concentrations until 7 days post partum.

Animals↗
PubMed2000

Natural and artificial methods for inducing the luteal phase in the koala (Phascolarctos cinereus).

An experiment was conducted in which female koalas were mated for different durations of intromission and ejaculation to confirm that the luteal phase of the oestrous cycle in koalas is induced by the physical act of mating. Results showed that induction of a luteal phase in the koala usually required a complete duration of penile thrusting behaviour from the male. It is proposed that induction of a luteal phase in koalas may involve a copuloceptive reflex, triggered by the thrusting of the male's penis into the female's urogenital sinus. Although interrupted mating in koalas may be used to induce a luteal phase in preparation for an artificial insemination programme, this study showed that there is a 12.5% probability that pregnancy will result from semen prematurely emitted by the teaser male. A dose of 250 iu hCG was administered intramuscularly to eight oestrous females to determine whether it was possible to induce a luteal phase artificially. In contrast to control females, which received sterile saline injections, all females injected with hCG showed a significant increase in progestogen concentration above that of basal values, indicating that a luteal phase had been induced successfully.

Animals↗
PubMed1996

Epirubicin, cisplatin, and protracted venous infusion of 5-fluorouracil for esophagogastric adenocarcinoma: response, toxicity, quality of life, and survival.

BACKGROUND: The results of chemotherapy for patients with esophagogastric carcinoma have generally been modest but regimens developed more recently have produced higher response rates, and rekindled interest in neoadjuvant chemotherapy. One such regimen is epirubicin, cisplatin, and 5-fluorouracil (ECF). This study evaluates its efficacy, toxicity, impact on quality of life (QL), and impact on survival in a large consecutive series of patients with metastatic and locally advanced disease (LAD). METHODS: Patients with histologically confirmed esophagogastric carcinoma were treated with ECF (epirubicin 50 mg/m2 and cisplatin 60 mg/m2 every 3 weeks with continuous infusion of 5-fluorouracil (5-FU) 200 mg/m2/d). Responses were evaluated with computed tomography (CT) scan and endoscopy. QL was assessed using the European Organization for Research and Treatment of Cancer QLQ-C30 questionnaire. RESULTS: A total of 235 patients were treated, 173 with metastatic disease and 62 with LAD. The mean number of cycles delivered was 6 (range: 1-11) and patients were followed-up for a median of 8 months. Response was observed in 135 of 220 (61%) evaluable patients, with a complete response (C(R)), 11% of the patients and a partial response in 50% of the patients. Patients with moderately differentiated adenocarcinomas and LAD responded most favorably. Symptomatic improvement was achieved in the majority of cases (63-78% depending on the symptom). Toxicity was generally only mild to moderate, with severe non hematologic toxicity in less than 12% of the patients and only 6 (2.5%) treatment related deaths. QL assessment showed no significant negative impact on emotional functioning and good symptomatic control. Surgery following response to ECF was performed in 29 of the LAD patients, and in 19 cases (66%) a potentially curative resection was possible, with histologic CR in 32% of the patients. CONCLUSIONS: ECF is a highly active regimen with acceptable toxicity in patients with esophagogastric adenocarcinoma. In a proportion of patients with LAD, chemotherapy enabled potentially curative surgery to be performed. The results justify further investigation of this regimen in a neoadjuvant setting.

Adenocarcinoma↗
PubMed1996

MRI in the evaluation of late bone marrow changes following bone marrow transplantation.

Measurements of MR spin-lattice (T1), and spin-spin (T2) relaxation times in lumbar vertebrae have been performed in a pilot study on six adult patients, treated for acute myeloid leukaemia (AML). All patients were treated with initial chemotherapy and then proceeded to bone marrow transplantation (BMT), conditioned with Melphalan and total body irradiation (TBI). MR measurements were made between 21 and 89 months after TBI. The relaxation times in the six patients were compared with those in six healthy age-matched volunteers to establish whether there were differences between the two groups. Average T1 values in the vertebrae of the treated patients are significantly shorter (p < 0.01) than in the healthy volunteers. This is consistent with the observation of a relatively hyperintense vertebral bone marrow in the T1 weighted images and is likely to be a consequence of treatment induced fatty replacement of marrow. Shorter T1 values tend to be distributed within the centre of the lumbar vertebrae compatible with observations, made by others, which suggest that the peripheral zone of the vertebral body has been repopulated with bone marrow cells whereas the central zone, around the basivertebral vein, is predominantly fat. Histogram displays of vertebral body relaxation time distributions (T1, T2) for both patients and healthy age-matched volunteers are similar in that both patients and volunteers give histograms that are only slightly skewed. This similarity is probably a reflection of the fact that the patients have been in remission for over a year and have generally healthy bone marrow.

Acute Disease↗
PubMed1995

Adjuvant chemotherapy for oesophagogastric cancer with epirubicin, cisplatin and infusional 5-fluorouracil (ECF): a Royal Marsden pilot study.

Previous trials of adjuvant chemotherapy for oesophagogastric cancer have shown only modest or no improvement in survival. However, the regimens used in these studies produce low response rates in patients with advanced disease. ECF is a new regimen which results in higher response rates and may therefore be more effective in the adjuvant setting. Twenty-nine patients who had undergone a potentially curative resection for oesphagogastric carcinoma were treated with ECF [epirubicin 50 mg m-2 and cisplatin 60 mg m-2 for 18 weeks]. The median age was 52.5 years. Three patients had oesophageal tumours, 14 had tumours of the oesophagogastric junction (OGJ) and 12 had gastric tumours. All were adenocarcinomas apart from one undifferentiated carcinoma. One patient had stage I disease, nine stage II, 17 stage II and two stage IV. The mean number of chemotherapy cycles per patient was 5.2 (range 2-8). The median follow-up was 8.4 months (1.5-36.3 months). Eleven patients relapsed during follow-up (38%). One patient had an anastomotic recurrence and ten patients distant metastases. Overall 3 year survival was 61.5% (95% confidence interval 42-79); 3 year survival in stage II was 50% (21.2-86.3) and in stage III 65.6% (40-86). Chemotherapy was well tolerated, with grade 3/4 toxicity as follows: leucopenia 13.5%, nausea and vomiting 10%, diarrhoea 3.5%, infection 3.5% and thrombocytopenia 3.5%. There were no treatment-related deaths. We conclude that ECF can be administered safely as adjuvant treatment to patients with surgically resected gastro-oesophageal carcinoma. The results, especially in patients with stage III disease, are encouraging and support the investigation of this regimen within a prospective randomised trial.

Adenocarcinoma↗
PubMed1995

Normal pelvic lymph nodes: evaluation with CT after bipedal lymphangiography.

PURPOSE: To establish guidelines to determine the normal size of pelvic lymph nodes by correlating computed tomographic (CT) and lymphangiographic data. MATERIALS AND METHODS: Forty men in whom stage I testicular tumors were being treated underwent CT scanning 3-4 months after undergoing lymphangiography. The site, size, and number of nodes at CT scanning were documented. Maximum short-axis diameter (MSAD) was measured at four anatomic sites in the pelvis. Results were analyzed with histograms, and median and percentile values were calculated. RESULTS: There were 187 nodes measured in 27 men before lymphangiography. There were 1,801 nodes measured in 40 patients after lymphangiography. Median MSAD values at CT after lymphangiography were 5 mm or less; fewer than 2% of nodes had an MSAD greater than 10 mm. CONCLUSION: Almost all normal pelvic nodes are less than 10 mm MSAD, depending on the site. The low sensitivity of CT in depicting metastases to the pelvic lymph nodes might be improved by adopting upper limits of normal that reflect this size.

Adolescent↗
PubMed1995

Royal Marsden phase III trial of fluorouracil with or without interferon alfa-2b in advanced colorectal cancer.

PURPOSE: Phase II studies have shown that the combination of interferon alfa-2b (IFN) and fluorouracil (5-FU) is active in patients with metastatic colon cancer. This study was designed to investigate whether treatment with the combination of IFN and 5-FU could improve the response rate, duration of response, or survival compared with treatment with 5-FU alone. PATIENTS AND METHODS: Patients with histologically confirmed advanced colorectal cancer were randomized to receive 5-FU 750 mg/m2/d by continuous infusion for 5 consecutive days followed by weekly bolus 5-FU 750 mg/m2 either with or without IFN 10 MU subcutaneously three times weekly. Treatment was continued until disease progression or unacceptable toxicity for up to 12 months. RESULTS: Radiologic response was observed in 26 of 106 assessable patients (25%): 10 of 52 (19%) in the group that received 5-FU plus IFN (all partial responses [PRs]) and 16 of 54 (30%) in the 5-FU-alone group (three complete responses [CRs] and 13 PRs) (P = .21). There was similarly no significant difference between the two groups in progression-free survival (median, 3 months), 1-year survival, or overall survival (median, 8 months). However, patients who received IFN did experience significantly more toxicity in the form of leukopenia (P = .013), lymphopenia (P = .01), depression (P = .014), and alopecia (P = .002), and were significantly more likely to be withdrawn due to adverse events (P = .003). There were four toxic deaths, all of which occurred in patients who had received IFN. CONCLUSION: At the doses and schedules used in this study, IFN affords no benefit to 5-FU in terms of response and survival and significantly increases toxicity for patients with advanced colorectal cancer.

Adult↗
PubMed1995

Phase II study of continuous infusion fluorouracil and interferon alfa-2b in the palliation of malignant neuroendocrine tumors.

PURPOSE AND METHODS: Twenty-four patients with rapidly progressive neuroendocrine tumors were treated with a new regimen of continuous infusion fluorouracil for 20 weeks (200 mg/m2/d) together with interferon alfa-2b (5 MU three times per week). Maintenance interferon alfa at the same dose was continued after the initial 20-week period. RESULTS: Of 15 patients with carcinoid tumors, seven (47%) had an objective response, with a median duration of 20.5 months (range, 8.5 to 41), and five (33%) had stabilization of disease for between 3.5 and 42 months. Improvement in symptoms was reported by 10 patients (67%). Three early deaths occurred, all in patients with advanced disease. Of nine patients with neuroendocrine tumors other than carcinoid, three (33%) had an objective response that lasted 2.5 to 24.5 months, and five had disease stabilization for between 2.5 and 16 months. CONCLUSION: These data, particularly in respect to carcinoid tumors, are encouraging, especially since serious complications from treatment were limited. This regimen is not generally toxic, is well tolerated, and offers useful palliation and symptom control in patients with disease that does not respond to simple pharmacologic manipulations.

Adult↗
PubMed1995

Impact of protracted venous infusion fluorouracil with or without interferon alfa-2b on tumor response, survival, and quality of life in advanced colorectal cancer.

PURPOSE: The aim of this study was to investigate the effects of adding interferon alfa-2b (IFN) to protracted venous infusion fluorouracil (PVI 5-FU) from the start of treatment in patients with advanced colorectal cancer. PATIENTS AND METHODS: Patients who attended our unit with histologically confirmed advanced colorectal cancer were randomized to receive either PVI 5-FU 300 mg/m2/d via Hickman line, and IFN 5 MU subcutaneously three times weekly, or PVI 5-FU alone. Treatment was given for a maximum of two 10-week blocks, with a 2-week gap for reassessment of all parameters. Quality of life (QL) was measured by the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30 (QLQ-C30) pretreatment and every 6 weeks thereafter. RESULTS: A total of 160 patients were randomized, with 155 eligible for assessment. Radiologic response was observed in 43 patients (28%): 17 of 77 (22%) in the 5-FU-plus-IFN arm (all partial responses [PRs]) and 26 of 78 (33%) in the 5-FU-alone group (complete responses [CRs] and 22 PRs) (difference not significant). Symptomatic improvement occurred in the majority of patients, and equally in both arms: 61% to 80% depending on the symptom. There was no significant difference between the two groups in failure-free survival (median, 161 v 193 days) or overall survival (median, 328 v 357 days). However, patients who received IFN did experience significantly more toxicity in the form of leukopenia (P = .001), neutropenia (P = .04), mucositis (P = .008), and alopecia (P = .0002). There were no toxic deaths and few notable differences in QL between the two arms. CONCLUSION: This study confirms that PVI 5-FU is effective in treating the symptoms associated with metastatic colorectal carcinoma, with only mild to moderate toxicity and maintenance of QL. IFN 5 MU three times weekly does not enhance these palliative benefits.

Adolescent↗
PubMed1994

A phase II study in advanced gastro-esophageal cancer using epirubicin and cisplatin in combination with continuous infusion 5-fluorouracil (ECF).

PURPOSE: A phase II study was performed in patients with unresectable or metastatic gastric cancer evaluating the efficacy of a new chemotherapy schedule combining epirubicin and cisplatin with a continuous ambulatory infusion of 5-fluorouracil (ECF). PATIENTS AND METHODS: One hundred thirty-nine consecutive, previously untreated patients were given ECF. Of these, 128 had measurable disease. Epirubicin (50 mg/m2 i.v.) and cisplatin (60 mg/m2 i.v.) were administered every three weeks for 8 cycles during a 21 week continuous i.v. infusion of 5-fluorouracil (200 mg/m2/day). In total 773 cycles of chemotherapy were given. RESULTS: Objective tumour responses was seen in 91 (71%) of the 128 patients with measurable disease, of which 15 (12%) had a complete response. Twenty patients with locally advanced disease responding to ECF had attempted resection of the primary--11 (55%) were completely removed, 4 of these had no residual tumour in the resected specimen. The overall median survival was 8.2 months with 1 and 2 year survivals of 30% and 10% respectively. Grade 3 or 4 emesis occurred in 13%, stomatitis in 7%, diarrhoea in 4%, infection in 6%, leucopenia in 21% and thrombocytopenia in 8% of patients. Myelosuppression delayed treatment in 39 (5%) of the 773 cycles. Six of the 139 patients (4.3%) had treatment related deaths. There was no measurable reduction in quality of life during chemotherapy, while 67% of the 66 patients with dysphagia had complete resolution of this symptom. CONCLUSIONS: The ECF regimen displays high anti-tumour activity with moderate toxicity in patients with gastric cancer and in some cases enabled resection of previously inoperable tumours.

Adenocarcinoma↗
PubMed1993

EPIC: an effective low toxicity regimen for relapsing lymphoma.

We have treated 40 patients was relapsed or resistant lymphoma with the combination of Etoposide, Prednisolone, Ifosfamide and Cisplatin (EPIC). Complete response was obtained in 11 patients (28%) with an overall response of 58%. The presence of bulky disease (P < 0.005), elevated LDH serum levels (P < 0.005), response to prior chemotherapy (P < 0.01) and B symptoms (P < 0.005) were significantly associated with response. However on multivariate analysis only the presence of bulky disease and of B symptoms were independent adverse factors for response and for survival. The regimen was well tolerated with myelosuppression being the most common toxicity. Leucopenia < or 1,000 microliters-1 and thrombocytopenia < or = 25,000 microliters-1 developed in 27% and 4% of cycles respectively. There were no treatment related deaths. The EPIC regimen has equivalent activity to other reported cisplatin based regimens used in the treatment of recurrent lymphoma, but is associated with lower treatment related morbidity and mortality.

Adult↗
PubMedDate not supplied

CT evaluation of the resectability of gastric cancer postchemotherapy.

BACKGROUND: To determine the accuracy of CT in the postchemotherapy assessment of resectability of gastric cancer. METHODS: Thirty patients deemed to have unresectable gastric cancer on CT were studied. This was verified at laparotomy in 10 of these patients. Following initial assessment, all received three to eight cycles of chemotherapy aiming for disease control and potential resection. Serial CT examinations, endoscopy, and biopsy were performed after the fourth, sixth, and eighth cycle of treatment. The primary tumor and lymph nodes seen on CT were compared with operative findings. RESULTS: After completion of chemotherapy, CT findings were correct in 23 patients. Fourteen of them had operable tumors and nine were inoperable. However, the CT findings were either equivocal or incorrect in the remaining seven patients. CONCLUSION: Chemotherapy is now able to downstage a previously inoperable gastric cancer, and CT is an accurate method in identifying those patients who can proceed to resection.

Adenocarcinoma↗