Intraocular cannula for chronic drug delivery

An intraocular cannula system for chronic drug delivery was designed and tested in rabbits. The cannula was inserted through the pars plana and the tip positioned in the vitreous cavity (distal tip) in a site close to the retinal area of interest. The cannula was stabilized by a silicone plate that was sutured to the sceera. The proximal end of the cannula was attached to a larger diameter silicone tubing which served as a connector to the reservoir for chronic drug delivery. Rabbit eyes with implanted cannulas were followed clinically and electrophysiologically for up to one and a half years. They showed almost no adverse effects as a result of the implantation and cannula patency was demonstrated by the injection of sodium fluorescein through the cannula at various times following surgery.We believe that the implanted intraocular cannula, which allows chronic drug delivery, will be a valuable asset for research and possibly clinical studies.     

A simple multi-purpose cannula system for access to the brain and/or systemic vascular system of unanesthetized animals

By utilizing a pedestal system mounted on the skull containing a cerebral guide cannula with hub, and a vascular catheter which is exteriorized within the pedestal, an easily made, multi-purpose system has been developed using materials which are available from any scientific or medical supplier. This technique is adaptable for use in a wide variety of animal species and can be used in unanesthetized or anesthetized preparations.     

In Vivo release by vagal stimulation of L-[H] glutamic acid in the nucleus tractus solitarius preloaded with L-[H] glutamine

In anesthetized and paralyzed rats, using a push-pull perfusion technique, we examined the effect of bilateral vagal stimulation on the release of L-[³H] glutamic acid (L-[³H] Glu) from the nucleus tractus solitarius (NTS), after preloading the tissue either with L-[³H] Glu or L-[³H] glutamine (L-[³H] Gln). Vagal stimulation sufficient to produce a maximum fall of arterial pressure (AP) evoked release of L-[³H] Glu from the NTS when the tissue was preloaded with either ³H-Glu or ³H-Gln, and of D-[³H] aspartic acid (D-[³H) Asp) when this stable Glu analogue was used to preload the tissue. Results demonstrate that the precursor L-Gln is a good marker of the releasable pool of L-Glu in vivo and are consistent with the hypothesis that L-[³H] Glu is a neurotransmitter in the NTS, mediating the vasodepressor response from cardiopulmonary mechanoreceptors.     

Long-term potentiation in the dentate gyrus of the anaesthetized rat is accompanied by an increase in protein efflux into push-pull cannula perfusates

Changes in protein content of push-pull cannula perfusates from the dentate gyrus of anaesthetized rats were analyzed before and after the induction of long-term potentiation (LTP). LTP, induced by either high-frequency stimulation of the perforant path or raising the extracellular calcium concentration, was associated with increases in the protein content of the perfusates. Tetanically induced LTP was accompanied with a large but delayed increase (apparent in the second hour after the stimulation) in protein efflux. In contrast, when LTP was induced by the elevation of extracellular calcium concentration, a smaller but more immediate increase in protein efflux was observed. When 5-D-aminophosphonovalerate was used to block the induction of LTP, no increase was observed in either case. These results indicate that LTP in the dentate gyrus is accompanied by an increase in the efflux of proteins into push-pull cannula perfusates. The possible origins of these proteins and their role in LTP are discussed.     

Simple cannula for repeated intracerebral drug administration in rats.

A simply constructed cannulation system for chronic implantation in rats is described. The guide cannula, stylet and injection cannula are all made from stainless steel tubing, require litte time to construct, and are designed for minimum brain damage and atraumatic infusion into unanesthetized rats.     

MAJOR VASCULAR INJURY AND LAPAROSCOPY

Iatrogenic vascular trauma is a hazard that must be considered constantly during any laparoscopic procedure. We present a case of vessel penetration presenting as CO₂ embolism during insufflation where delayed recognition of the vascular implications of this event led to death from exsanguination. The pattern of laparoscopic vascular injuries in Australia as reported to the Medical Defence Union (UK) and the New South Wales Medical Defence Union is reviewed and compared with previously reported cases of vascular trauma in laparoscopy. Recommendations are made for the diagnosis and most importantly for the prevention of CO₂ embolism and major vascular injury at laparoscopy.     

Humidified high flow nasal cannulae: current practice in Australasian nurseries, a survey

Aim: Humidified High Flow Nasal Cannula (HHFNC) has been increasingly adopted as a new means of respiratory support throughout the world. However, evidence to support its safety and efficacy is limited. The aim of the present survey was to determine current practices regarding the usage of HHFNC by neonatologists in Australia and New Zealand. Methods: Surveys were sent to all 167 neonatologists identified by the list of centres in the Australia and New Zealand Neonatal Network. Results: A total of 157 surveys were sent to valid email addresses: 111 (71%) responded of which 105 (67%) had completed the questionnaire. HHFNC is used in 17 (63%) of neonatal intensive care units in Australia and New Zealand. It is most commonly used to reduce nasal trauma (91%) and provide continuous positive airways pressure (62%). The main perceived benefits of HHFNC were the easier application and care of the infant (86%), and improved tolerance by the baby (84%). Rain out leading to fluid instillation into the upper airway (59%) was the most common problem. Conclusion: This survey has provided a snapshot of the practice of HHFNC usage in Australia and New Zealand in 2010 and has revealed that HHFNC use is widespread and that clinical practices are diverse. The majority of neonatologists acknowledge that there is limited evidence to support its efficacy and safety, and would be happy to participate in clinical trials to address how best to deliver HHFNC.     

视可尼喉镜气管插管200例临床观察

目的:观察视可尼喉镜在气管插管的安全性和有效性。方法:选择ASA 1～3,年龄18～82岁需气管插管的患者200例,用视可尼喉镜置入气管导管内引导,采用从左侧嘴角进入口腔,放至左侧咽侧壁及目镜确认声门、气管的方法完成气管插管。结果:195例插管成功,成功率为97.5%,其中1次插管成功者151例(75.5%)、2次插管成功者23例(11.5%)、3次插管成功者20例(10.0%),插管失败5例(2.5%)。所有患者均无明显牙齿及咽喉黏膜损伤。结论:视可尼喉镜引导气管插管是一种简便、快捷、安全、高效、损伤小,临床实用有效的新技术。