Nitric oxide inhibits the release of norepinephrine and dopamine from the medial basal hypothalamus of the rat.

Previous research indicates that norepinephrine and dopamine stimulate release of luteinizing hormone (LH)-releasing hormone (LHRH), which then reaches the adenohypophysis via the hypophyseal portal vessels to release LH. Norepinephrine exerts its effect via alpha 1-adrenergic receptors, which stimulate the release of nitric oxide (NO) from nitricoxidergic (NOergic) neurons in the medial basal hypothalamus (MBH). The NO activates guanylate cyclase and cyclooxygenase, thereby inducing release of LHRH into the hypophyseal portal vessels. We tested the hypothesis that these two catecholamines modulate NO release by local feedback. MBH explants were incubated in the presence of sodium nitroprusside (NP), a releaser of NO, and the effect on release of catecholamines was determined. NP inhibited release of norepinephrine. Basal release was increased by incubation of the tissue with the NO scavenger hemoglobin (20 micrograms/ml). Hemoglobin also blocked the inhibitory effect of NP. In the presence of high-potassium (40 mM) medium to depolarize cell membranes, norepinephrine release was increased by a factor of 3, and this was significantly inhibited by NP. Hemoglobin again produced a further increase in norepinephrine release and also blocked the action of NP. When constitutive NO synthase was inhibited by the competitive inhibitor NG-monomethyl-L-arginine (NMMA) at 300 microM, basal release of norepinephrine was increased, as was potassium-evoked release, and this was associated in the latter instance with a decrease in tissue concentration, presumably because synthesis did not keep up with the increased release in the presence of NMMA. The results were very similar with dopamine, except that reduction of potassium-evoked dopamine release by NP was not significant. However, the increase following incubation with hemoglobin was significant, and hemoglobin, when incubated with NP, caused a significant elevation in dopamine release above that with NP alone. In this case, NP increased tissue concentration of dopamine along with inhibiting release, suggesting that synthesis continued, thereby raising the tissue concentration in the face of diminished release. When the tissue was incubated with NP plus hemoglobin, which caused an increase in release above that obtained with NP alone, the tissue concentration decreased significantly compared with that in the absence of hemoglobin, indicating that, with increased release, release exceeded synthesis, causing a fall in tissue concentration. When NO synthase was blocked by NMMA, the release of dopamine, under either basal or potassium-evoked conditions, was increased. Again, in the latter instance the tissue concentration declined significantly, presumably because synthesis did not match release. Therefore, the results were very similar with both catecholamines and indicate that NO acts to suppress release of both amines. Since both catecholamines activate the release of LHRH, the inhibition of their release by NO serves as an ultra-short-loop negative feedback by which NO inhibits the release of the catecholamines, thereby reducing the activation of the NOergic neurons and decreasing the release of LHRH. This may be an important means for terminating the pulses of release of LHRH, which generate the pulsatile release of LH that stimulates gonadal function in both male and female mammals.     

Treatment of residual common bile duct stones after cholecystectomy

This study was conducted to determine the occurrence of "open" residual common bile duct stones after cholecystectomy to establish predisposing factors and possible alternative treatments. Correct diagnosis of choledocholithiasis before or during surgery, adequate exploration of the common bile duct, and suitable selection of technical procedures are the most important points in preventing retained CBD stones. If these occur, an adequate alternative treatment may prove helpful. Classical "clysis" of the bile duct is least recommended because of its high failure rate. The best method of chemical dissolution seems to be the use of mono-octanoin with 60% good results and a no-response rate of 30-40%. Instrumental extraction has been reported to be very successful (80-98%). Endoscopic sphincterotomy is currently the most frequently employed procedure for retained CBD stones, especially in poor risk patients. The reported success rate is 82-93% according to literature, with an extremely low mortality (0.2%). Reoperation should be resorted to only if all the other methods fail. Sphincteroplasty or choledochoduodenostomy, whenever indicated, are good alternative operations, with a mortality rate of approx. 3.5%.     

Risk factors for pneumonia in the intubated patient

The information gathered here helps to explain why risk factors in the development of VAP vary from series to series. It also explains why different investigators have found opposite effects when evaluating the antibiotics. Antibiotic therapy has a bimodal effect in the development of VAP. Antibiotics protect against pneumonia development within the first days of MV, especially against types caused by endogenous flora, but they are responsible for selection of a set of resistant pathogens that are associated with significant attributable mortality, such as P aeruginosa and MRSA. These observations suggest that risk factors vary depending on the exposure to risk (ie, length of stay or MV). This variable should be considered when stratifying patients for risk factor analysis and also in the design of clinical trials for VAP prophylaxis.     

Initial report of a mycotic aneurysm of the common iliac artery with compression of the ipsilateral ureter and femoral vein: a literature review and case report

Iliac artery aneurysms are rare and the usual symptoms, pelvic pain and urological complaints, are nonspecific. We describe a patient with pelvic pain, intermittent urinary retention, and lower extremity edema. A right common iliac artery aneurysm was discovered during surgery after rupture had occurred. Pathologic examination revealed a mycotic process. This case demonstrates the obscure and unreported clinical features of iliac artery aneurysms. When this lesion is suspected, an angiogram should be performed promptly in an effort to prevent the predictable catastrophic consequences.     

Cerebral toxoplasmosis following etanercept treatment for idiophatic pneumonia syndrome after autologous peripheral blood progenitor cell transplantation (PBPCT)

Idiophatic pneumonia syndrome (IPS) is a term used to describe lung injury following hematopoietic stem cell transplantation (HSCT) without an infectious etiology. Diagnostic criteria include multilobar infiltrates on chest X-ray, clinical symptoms consistent with pneumonia and evidence of abnormal pulmonary physiology. The incidence after autologous transplantation is low (6%) but it has a high mortality (70–80%). Treatment with high-dose steroids has been used but the results are discouraging. Etanercept is a recombinant human soluble TNF receptor fusion protein that inhibits tumor necrosis factor (TNF) function. Recently, promising results have been obtained with etanercept for the treatment of acute and chronic GVHD after HSCT, but there is a little information regarding adverse effects. We report a case of IPS after autologous peripheral blood progenitor cell transplantation (PBPCT) successfully treated with etanercept. The patient developed cerebral toxoplasmosis immediately after etanercept treatment with a good outcome.