Biomedical subjects
John Collins
Publications and source records attributed to John Collins.
Spontaneous pregnancies in couples who discontinued intracytoplasmic sperm injection treatment: a 5-year follow-up study.
OBJECTIVE: To analyze the occurrence of deliveries after spontaneous conception in patients who have discontinued unsuccessful intracytoplasmic sperm injection (ICSI) treatment. DESIGN: Cohort follow-up study. SETTING: Tertiary referral center. PATIENT(S): Between July 1992 and December 1993, 200 Belgian women younger than 37 years underwent 433 consecutive unsuccessful ICSI cycles with freshly ejaculated sperm and eventually discontinued their treatment. INTERVENTION(S): Ultrasound-guided oocyte retrieval and ICSI. MAIN OUTCOME MEASURE(S): Delivery after 25 weeks following a spontaneous pregnancy. RESULT(S): The mean age at the time of the last oocyte pick-up was 31.0 +/- 3.9 years. The mean time interval between the last ICSI and the end of the follow-up period was 47.7 +/- 12.1 months. Twenty-three spontaneous pregnancies ending in delivery after 25 weeks were observed (11.5%). The cumulative delivery rate reached a plateau of 10% after 36 months of follow-up. The mean time interval (from last oocyte retrieval) for spontaneous pregnancy to occur after discontinuing ICSI treatment was 20.2 +/- 13.7 months. Proportional hazards analysis showed that delivery rate was reduced by 2.0% per year of infertility. CONCLUSION(S): This study suggests that duration of infertility appears to be predictive of the likelihood of live delivery after spontaneous conception following an unsuccessful ICSI treatment.
SRC-1 and Wnt signaling act together to specify endoderm and to control cleavage orientation in early C. elegans embryos.
In early C. elegans embryos, signaling between a posterior blastomere, P2, and a ventral blastomere, EMS, specifies endoderm and orients the division axis of the EMS cell. Although Wnt signaling contributes to this polarizing interaction, no mutants identified to date abolish P2/EMS signaling. Here, we show that two tyrosine kinase-related genes, src-1 and mes-1, are required for the accumulation of phosphotyrosine between P2 and EMS. Moreover, src-1 and mes-1 mutants strongly enhance endoderm and EMS spindle rotation defects associated with Wnt pathway mutants. SRC-1 and MES-1 signal bidirectionally to control cell fate and division orientation in both EMS and P2. Our findings suggest that Wnt and Src signaling function in parallel to control developmental outcomes within a single responding cell.
Hormone replacement therapy and breast cancer, revisited.
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Macro-aspartate aminotransferase in a female with antibodies to hepatitis C virus.
Persistent elevation of aspartate aminotransferase (AST) activity in serum due to the presence of a macroenzyme form of AST (macro-AST) may lead to diagnostic confusion in many clinical conditions, particularly those associated with chronic liver disease. We describe a case of macro-AST arising in an adult female with a false-positive hepatitis C virus (HCV) RNA test result that was not accompanied by other biochemical or histologic evidence of liver disease. The presence of macro-AST in serum was confirmed utilizing size-exclusion, high performance liquid chromatography (HPLC) and Protein G-agarose beads to precipitate immune complexes of AST and immunoglobulin G followed by centrifugation and AST activity measurements in the supernatant. A brief review of the clinical enzymology of AST and methods used to quantify serum macro-AST activity is provided.
Colonoscopy has a high diagnostic yield and low complication rate in older patients.
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The economic consequences of multiple gestation pregnancy in assisted conception cycles.
This study estimates the projected costs of multiple births resulting from assisted conception cycles (in vitro fertilization with or without intracytoplasmic sperm injection and ovarian stimulation with gonadotrophin). The estimates are modelled from the volume of services, treatment success and multiple gestation rates in recent registry data. The coverage is restricted to hospital costs associated with delivery and the trends are projected to 2000 in the United States. Sensitivity analyses tested different assumptions about per annum trends in effectiveness, multiple pregnancy rates and health costs. The national cost of in vitro fertilization cycles is US$470.2 million (£313.5 million) and the cost of the multiple pregnancies from in vitro fertilization is US$639.9 million (£426.7 million). The national cost of ovarian stimulation cycles is US$166.6 million (£111.1 million) and the cost of the multiple pregnancies from ovarian stimulation is US$257.3 million (£171.6 million). Although costs are a limited indicator of the burden of illness, the projected national cost of multiple pregnancy associated with assisted conception in 2000 is greater than the base cost of the treatment. Prevention of multiple pregnancy in assisted conception cycles should be a priority.
Changes in the management of ductal carcinoma in situ before the release of clinical practice recommendations in Australia: the case in Victoria.
BACKGROUND: This study examines changes in the management of ductal carcinoma in situ between 1995 and 1999 in the Australian State of Victoria. This period was before the release of Australian treatment recommendations. METHODS: All new cases of ductal carcinoma in situ diagnosed between 1 April and 30 September in 1995 and 1999 were identified from the population cancer registry. Treating surgeons completed a questionnaire on the presentation and management of each case. In 1995, 64 out of 70 surgeons returned questionnaires for 137 cases (case response, 94%). In 1999, 68 surgeons treated 159 registered cases and 141 completed surveys were returned (case response, 89%). RESULTS: More cases underwent an image-guided biopsy in 1999 (54%) than in 1995 (34%). Breast-conserving surgery (BCS) was used to treat 69% of cases in 1999 and 63% in 1995. The use of axillary procedures (clearance or sampling) for women treated by mastectomy decreased from 61% in 1995 to 30% in 1999. More patients treated with BCS had margins simply described as "clear" in 1995 (49%) than in 1999 (21%). In 1995, only 7% of cases treated with BCS had radiotherapy, and this was 25% in 1999. CONCLUSION: In both 1999 and 1995, the majority of patients were treated by BCS, but only a minority received radiotherapy.
The relationship between physicians and the biomedical industries: advice from the Royal College of Physicians.
The relationship between a physician and a biomedical firm is often important, and can be useful to both parties. However, there is a danger that the substantial resources available to a biomedical firm might sometimes be used to interfere with a physician's independent professional judgment. For the reputation and good conduct of the profession and the industry, and for the welfare of patients, it is essential that this does not happen. Total absence of communication would prejudice the undoubted good which collaboration can achieve. This paper sets out what the Royal College of Physicians currently believes are appropriate boundaries: to the acceptance of gifts; to sponsorships and subsidies for meetings; to the conduct of meetings with industry representatives; and other matters. We believe that clearly stated guidance will benefit the biomedical industry and physicians alike.