Biomedical subjects
B Soin
Publications and source records attributed to B Soin.
Controlled trial of the introduction of a robotic camera assistant (EndoAssist) for laparoscopic cholecystectomy.
BACKGROUND: The role of the human camera holder during laparoscopic surgery keeps valuable personnel from other duties. EndoAssist is a robotic camera-holding device controlled by the operator's head movements. This study assesses its introduction into clinical practice. METHOD: Ninety-three patients undergoing laparoscopic cholecystectomy were randomized to have either the robotic (40) or a human (46) assistant. Seven patients converted to open operation were excluded. Six surgeons were evaluated. Operating time and subjective assessments were recorded. Learning curves were constructed. RESULTS: The mean operating time was less using the robotic assistant (66 min) than with human assistance (74 min) (p < 0.05, two-tailed t-test). The learning curves for operating time showed that within three operations surgeons were trained in using the robot. The device was safe in use. CONCLUSION: The EndoAssist operating device is a significant asset in laparoscopic surgery and a suitable substitute for a human assistant. Surgeons became competent in the use of the robot within three operations. The robot offers stability and good control of the television image in laparoscopic surgery.
Physiological aspects of pig-to-primate renal xenotransplantation.
BACKGROUND: Few data exist on the physiological aspects of pig-to-primate renal xenotransplantation. METHODS: Use of organs transgenic for human decay accelerating factor has allowed assessment of the metabolic and hormonal functions of these xenografts. RESULTS: Porcine renal xenografts largely maintain plasma electrolyte homeostasis. An increase in proteinuria was detected that may result from graft injury. In contrast to allotransplantation a severe anaemia developed requiring recipient treatment with exogenous human erythropoietin. CONCLUSIONS: Our experience provides qualified encouragement for the likely physiological compatibility of pig and primate species, but identifies areas where a xenograft may not match the performance of an allograft.
Absence of hyperacute rejection and preservation of function in HDAF transgenic pig kidneys exposed to prolonged cold ischaemia.
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Genetic engineering of the donor as an approach to clinical xenotransplantation.
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Growth of porcine kidneys in their native and xenograft environment.
The increased survival of hDAF pig-to-primate renal xenografts for up to two months has afforded the opportunity to study physiological aspects such as organ growth. Experimental evidence exists of species restriction of the activity of growth hormone, although growth itself is also controlled by a number of other endocrine, paracrine and autocrine substances. This study consisted of four parts: (1) measurement of pig kidney size according to pig body weight; (2) measurement of pig kidney size according to pig age; (3) serial length measurement of pig-to-primate renal xenografts; (4) correlation of terminal weight of renal xenograft with age and histology. The xenografted pig kidneys in a primate recipient grow as they would in the pig for the first two weeks after transplantation. After this time there is a reduction in the rate of increase in the length of the xenograft. Over the same period, changes in weight are greatly increased by the presence of rejection. This observational study supports the notion that regulation of growth of a xenotransplanted porcine kidney occurs.
Xenotransplantation.
BACKGROUND: The success of clinical transplantation has led to a large discrepancy between donor organ availability and demand; considerable pressure exists to develop an alternative source of organs. The use of animal organs for donation is a possible solution that is not yet clinically applicable. METHODS AND RESULTS: A literature review was performed based on a Medline search to find articles on xenotransplantation. Keywords included hyperacute, acute vascular, xenograft rejection combined with concordant and discordant. Additional references cited in these articles from journals not included in Medline were obtained from the British Library. Limited information on unpublished, preliminary work has been included from sources known to the authors, based on their research work in the field. One hundred and forty-six references and four personal communications have been included in this review article. CONCLUSION: A greater understanding of the pathogenesis of xenograft rejection is developing rapidly. Strategies to abrogate hyperacute rejection have proved successful, but control of antibody-driven acute vascular rejection has not yet been achieved. The safety and viability of xenotransplantation as a therapeutic modality are still unproven.
Progress in xenotransplantation.
BACKGROUND: XT using the pig as a donor species may provide a potential solution to the lack of human organs available for transplantation. However, two major immunological obstacles have impeded the survival of porcine organs transplanted into primates. The first is hyperacute rejection (HR), which is a consequence of the recipient's preformed antibodies binding specifically to the carbohydrate structure Gal-alpha1-3-Gal on porcine endothelial cells (EC), leading to complement activation and graft failure. Conventional strategies to overcome HR have focused on the inactivation or removal of essential components of the complement system, or removal of anti-xenograft antibodies from the blood of the recipient. Alternatively, genetically modified donor pigs, whose organs express human complement inhibitors such as human decay-accelerating factor (hDAF), have been produced. AIM: Several groups have shown that organs from these transgenic pigs do not undergo HR when transplanted into primates. Acute vascular rejection (AVR) is the second major immunological obstacle to successful XT. Several strategies are presently being investigated to overcome this form of rejection. The first approach is aimed at controlling the induced anti-xenograft humoral response with immunosuppressive agents primarily directed against lymphocytes. A second approach is aimed at preventing EC activation in the graft by inhibition of NF-kappaB, a transcription factor which is known to play a central role in EC activation. A third approach is aimed at preserving the antithrombotic properties of EC which usually disappear when these cells are activated. Finally, other groups are attempting to tackle AVR by exploring the role of platelet inhibitors or by using antibodies directed against adhesion molecules. To date, the speed and strength of the humoral xenograft rejection process have impeded in vivo studies of the cell-mediated immune response in the pig-to-primate model. However, there is now evidence that human T cells respond vigorously to pig MHC antigens and some authors have proposed that the induction of tolerance is essential if XT is to succeed clinically. It is clear that additional in vivo data still need to be generated in order to fully comprehend the involvement of the cellular immune response in this model. CONCLUSIONS: It has now been demonstrated that organs from hDAF transgenic pigs sustain the life of primates for up to 12 weeks before failing due to the onset of AVR. It is anticipated that once AVR has been overcome, long-term survival of porcine organs transplanted into primates should be reproducibly achievable.
Initial experience with an absorbable laparoscopic ligation clip.
BACKGROUND: Laparoscopic surgery requires secure and safe methods of ligation and haemostasis. This study evaluated the efficacy of an absorbable ligation clip with a novel compression closure mechanism. METHODS: A new compression-closure absorbable clip was compared with currently available absorbable and non-absorbable clips used in a variety of laparoscopic procedures in 12 centres worldwide. RESULTS: At follow-up to 3 months after the procedure, no complications specific to the use of the compression-closure clip were detected. Operator satisfaction with the clip was high, with criticism directed at its relatively large size. CONCLUSION: This new clip is as safe and effective as presently available metal and absorbable clips in providing haemostasis and securing tubular structures.
An unusual forearm fracture in a child suggesting a mechanism for the Monteggia injury.
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Informed consent: a case for more education of the surgical team.
A questionnaire was given to 37 members of staff of the Department of Surgery, Addenbrooke's Hospital, Cambridge, in order to determine whether their knowledge was adequate to give accurate information to patients regarding operations and thus to obtain properly informed consent for that operation. Each participant was asked to estimate the 24-h and 30-day mortality for five common elective operations. A wide range of answers was given for operations by all groups. Estimates of 24-h mortality after unilateral inguinal herniorrhaphy differed between staff grades by a factor of 3, but estimates of 24-h mortality after thyroidectomy differed by a factor of 100 between consultant surgeons and staff nurses. Our findings suggest that some members of the surgical team have insufficient knowledge about common operations to obtain properly informed consent from patients.
Acute vascular rejection of h-DAF transgenic porcine kidneys in immunosuppressed cynomolgus monkeys is associated with systemic and intragraft complement activation.
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