Use of CO2 to move structures as an aid to percutaneous procedures

By injecting small amounts of CO2 through a needle, one can move bowel or bladder from the intended path of instruments during interventional procedures. The technique worked well in six of seven cases in the pelvis and retroperitoneum; it was not effective in the mediastinum or midabdomen (n = 6).     

Development of tolerance to the CNS effects of aminoglutethimide in mice

Initially, there is a high incidence of CNS-depressant side-effects when the aromatase inhibitor, aminoglutethimide, is used in the treatment of patients with advanced breast cancer. Tolerance to these effects develops with continued dosing. This study examines the development of tolerance to various indices of CNS depression with the drug in mice. Single doses of aminoglutethimide induced a dose-dependent depression of spontaneous locomotor activity, rotarod performance, righting reflex and body temperature and a dose-related antileptazol activity. On repeated dosing with the drug, tolerance to these various activities occurred. The tolerance was found to be dose-dependent in the rotarod and righting reflex tests and time-dependent in the locomotor and body temperature tests. Although the results do not allow a determination of whether this clearly demonstrated phenomenon in the mouse is primarily functional or dispositional, the slow onset (14 days) for complete tolerance may be indicative of a functional mechanism.     

Anesthesia for trauma

Trauma is the leading cause of death for persons aged 1 to 38 years. Successful management is facilitated by prehospital endotracheal intubation, transport to regional trauma centers, rapid resuscitation by an on-site team of trained physicians, timely operative intervention, and provision of care by well-prepared anesthesiologists familiar with the potential complications typical of traumatized patients. No particular anesthetic agent or technique is ideal. Causes for intraoperative hypotension include hypovolemia, hemopneumothorax, pericardial tamponade, an intracranial mass, acidosis, and hypothermia. The anesthesiologist should play an active role in all phases of trauma management, including provision of postoperative intensive care and pain relief.     

外科手术中产生的烟气:仅仅是大量的热空气吗?

外科医生和手术室人员经常接触手术设备产生的烟气,病人也会暴露于烟气中,特别是腹腔镜手术中产生的烟气滞留于腹腔内这一密闭空间并被吸收.这些烟气是一种与香烟烟气相似的毒性物质,然而对这种毒性物质的影响还未引起足够重视.应该采取必要措施尽可能减少手术中烟气的不良影响.     

The release and uptake of excitatory amino acids

In this article, David Nicholls and David Attwell describe recent advances in our understanding of the mechanisms by which excitatory amino acids are released from cells, and of the way in which a low extracellular glutamate concentration is maintained. Glutamate can be released from cells by two mechanism: either by Ca2(+)-dependent vesicular release or, in pathological conditions, by reversal of the plasma membrane uptake carrier. The contrasting pharmacology and ionic dependence of the glutamate uptake carriers in the vesicle membrane and in the plasma membrane explain how glutamate (but probably not aspartate) can function as a neurotransmitter, and why the extracellular glutamate concentration rises to neurotoxic levels in brain anoxia.     

Characterization of P1-purinoceptors on rat duodenum and urinary bladder.

1. The P1-purinoceptors mediating relaxation of the rat duodenum and inhibition of contraction of the rat urinary bladder were characterized by use of adenosine and its analogues 5'-N-ethylcarboxamidoadenosine (NECA), N6-cyclopentyladenosine (CPA) and 2-p-((carboxyethyl)phenethylamino)-5'- carboxamidoadenosine (CGS 21680), as well as the A1-selective antagonist 1,3-dipropyl-8-cyclopentylxanthine (DPCPX). The stable analogue of adenosine 5'-triphosphate (ATP), adenylyl 5'-(beta,gamma-methylene)diphosphonate (AMPPCP), was also used as previous work had indicated that it has a direct action on some P1 receptors in addition to its P2-purinoceptor activity. 2. In the rat duodenum, the order of potency of the adenosine agonists was NECA greater than or equal to CPA greater than AMPPCP = adenosine greater than CGS 21680, and DPCPX antagonized CPA and AMPPCP at a concentration of 1 nM whereas equivalent antagonism of NECA and adenosine required a concentration of 1 microM. This suggests the presence of a mixture of A1 and A2 receptors in this tissue, with CPA and AMPPCP acting on the A1 and NECA and adenosine acting on the A2 receptors. 3. In the rat bladder, the order of potency of the adenosine agonists for inhibition of carbachol-induced contractions was NECA much greater than adenosine greater than CPA = CGS 21680, and a concentration of DPCPX of 1 microM was required to antagonize responses to NECA and adenosine. This suggests the presence of A2 receptors in this tissue.(ABSTRACT TRUNCATED AT 250 WORDS)     

Proteolytic processing of the Plasmodium falciparum merozoite surface protein-1 produces a membrane-bound fragment containing two epidermal growth factor-like domains.

The amino-terminal sequence has been obtained for 2 fragments of the Plasmodium falciparum T9/94 merozoite surface protein precursor (PfMSP1) and these have been compared with the sequence predicted from the gene. These data define the position of these fragments in the precursor and indicate that the C-terminal sequence which is carried into the red cell during invasion consists of 2 epidermal growth factor (EGF)-like domains. A homologous cleavage sequence and domain structure can be identified in the MSP1 molecules of other malarial species. In addition the results suggest that the smaller fragment is not N-glycosylated.     

Environmental temperature and stroke in a subtropical climate.

The effect of environmental temperature on stroke occurrence in a subtropical climate was studied over a 1-year period by documenting the number of strokes (subdivided into cerebral infarct and intracerebral hemorrhage) admitted into a district hospital in Hong Kong at different temperatures. There was no significant correlation between the number of strokes (or its subtypes) per day per temperature category and the environmental minimum or maximum temperature. However, an association was present between the occurrence of cerebral infarcts and maximum temperature on the day of onset in elderly patients aged 70 years and above. Environmental temperature is not a strong risk factor for the occurrence of stroke in a subtropical climate.