Protein kinase C regulates ionic conductance in hippocampal pyramidal neurons: electrophysiological effects of phorbol esters.

The vertebrate central nervous system contains very high concentrations of protein kinase C, a calcium- and phospholipid-stimulated phosphorylating enzyme. Phorbol esters, compounds with inflammatory and tumor-promoting properties, bind to and activate this enzyme. To clarify the role of protein kinase C in neuronal function, we have localized phorbol ester receptors in the rat hippocampus by autoradiography and examined the electrophysiological effects of phorbol esters on hippocampal pyramidal neurons in vitro. Phorbol esters blocked a calcium-dependent potassium conductance. In addition, phorbol esters blocked the late hyperpolarization elicited by synaptic stimulation even though other synaptic potentials were not affected. The potencies of several phorbol esters in exerting these actions paralleled their affinities for protein kinase C, suggesting that protein kinase C regulates membrane ionic conductance.     

Subcellular sites of synthesis of phosphatidylglycerol and phosphatidylinositol in type II pneumonocytes

The subcellular sites of synthesis of phosphatidylinositol and phosphatidylglycerol in type II pneumonocytes isolated from lungs of adult rats were investigated. Microsomes contained approximately 34% of the total cellular activity of CDP-diacylglycerol: inositol 3-phosphatidyltransferase (EC 2.7.8.11) but less than 10% of the total activity of CDP-diacylglycerol: glycerol 3-phosphate phosphatidyltransferase (EC 2.7.8.5) and the latter activity could be attributed to mitochondrial contamination of the microsomal fraction. A crude mitochondrial fraction contained approximately 90% of the total cellular activity of CDP-diacylglycerol: glycerol 3-phosphate phosphatidyltransferase and also contained more than 50% of the total CDP-diacylglycerol: inositol 3-phosphatidyltransferase activity. When the crude mitochondrial fraction was subfractionated by use of discontinuous density gradient centrifugation, the distribution of CDP-diacylglycerol: inositol 3-phosphatidyltransferase activity was similar to that of NADPH: cytochromec reductase activity but dissimilar to the distribution of CDP-diacylglycerol: glycerol 3-phosphate phosphatidyltransferase activity which resembled that of succinate dehydrogenase. Electron microscopy of subcellular fractions revealed that fractions rich in CDP-diacylglycerol: inositol 3-phosphatidyltransferase activity contained numerous smooth membrane vesicles, whereas fractions rich in CDP-diacylglycerol: glycerol 3-phosphate phosphatidyltransferase activity contained mainly mitochondria. We conclude that the subcellular sites of synthesis of phosphatidylinositol and phosphatidylglycerol in type II pneumonocytes are most likely the endoplasmic reticulum and mitochondria, respectively. The results of this investigation were presented, in part, at the 73rd annual meeting of the American Society of Biological Chemists     

Peripheral-type benzodiazepine receptors in endocrine organs: autoradiographic localization in rat pituitary, adrenal, and testis

We have used [3H]Ro5-4864, a ligand selective for peripheral-type benzodiazepine receptors, to identify and localize peripheral-type benzodiazepine receptors in endocrine organs. Autoradiographic studies reveal an uniform distribution of [3H]Ro5-4864 binding sites within the anterior, intermediate, and posterior lobes of the pituitary gland, with highest concentrations present in the posterior pituitary. In rat adrenal gland, specific binding sites for [3H]Ro5-4864 are found only in the adrenal cortex, with highest density in the zona glomerulosa and significantly lower concentrations in the zona fasciculata and zona reticularis. [3H]Ro5-4864-associated silver grains in the testis are intensely localized over the interstitial tissue; low concentrations of silver grains are present over the epithelium of the seminiferous tubules but are absent from the tubular lumen. These studies demonstrate a differential and discrete localization of peripheral-type benzodiazepine receptors in rat pituitary, adrenal, and testis.     

Barotrauma and hypotension resulting from jet ventilation in critically ill patients

We present the first reports of pneumoperitoneum secondary to jet ventilation, barotrauma secondary to jet ventilation through the suction port of a fiberoptic laryngoscope, and hypotension due to jet ventilation via nasotracheal and orotracheal catheters. We suggest that minimizing airway pressure and using jet catheters with side holes may help decrease the risk of such complications. We cannot, at present, recommend the use of hand-held jet ventilators unless both adequate exhalation space is guaranteed and direct impingement of the catheter's tip on the mucosal surface is avoided.     

Cutaneous blisters and carbon monoxide poisoning

We present the cases of three patients with skin blisters following carbon monoxide (CO) poisoning. Their blisters appeared to be related to the severity of the poisoning (HbCO levels of more than 40%). Two of the three patients died despite aggressive initial 100% surface oxygen followed by hyperbaric oxygen therapy. The pathophysiology of this type of blister remains unresolved. It could result from pressure necrosis alone or from a combination of pressure necrosis and direct CO inhibition of tissue oxidative enzymes. Although skin involvement as a result of CO poisoning is less frequently reported today than in the past (perhaps because of misidentified burns or because of more aggressive resuscitation and treatment protocols), the physician should recognize that such blisters may signal severe CO poisoning.     

Report of a Consensus Conference on Transplant Program Quality and Surveillance

Public reports of organ transplant program outcomes by the US Scientific Registry of Transplant Recipients have been both groundbreaking and controversial. The reports are used by regulatory agencies, private insurance providers, transplant centers and patients. Failure to adequately adjust outcomes for risk may cause programs to avoid performing transplants involving suitable but high‐risk candidates and donors. At a consensus conference of stakeholders held February 13–15, 2012, the participants recommended that program‐specific reports be better designed to address the needs of all users. Additional comorbidity variables should be collected, but innovation should also be protected by excluding patients who are in approved protocols from statistical models that identify underperforming centers. The potential benefits of hierarchical and mixed‐effects statistical methods should be studied. Transplant centers should be provided with tools to facilitate quality assessment and performance improvement. Additional statistical methods to assess outcomes at small‐volume transplant programs should be developed. More data on waiting list risk and outcomes should be provided. Monitoring and reporting of short‐term living donor outcomes should be enhanced. Overall, there was broad consensus that substantial improvement in reporting outcomes of transplant programs in the United States could and should be made in a cost‐effective manner.     

Transplanted neural stem cells survive,differentiate, and improve neurological motor function after experimental traumatic brain injury

OBJECTIVE: Using the neural stem cell (NSC) clone C17.2, we evaluated the ability of transplanted murine NSCs to attenuate cognitive and neurological motor deficits after traumatic brain injury. METHODS: Nonimmunosuppressed C57BL/6 mice (n = 65) were anesthetized and subjected to lateral controlled cortical impact brain injury (n = 52) or surgery without injury (sham operation group, n = 13). At 3 days postinjury, all brain-injured animals were reanesthetized and randomized to receive stereotactic injection of NSCs or control cells (human embryonic kidney cells) into the cortex-hippocampus interface in either the ipsilateral or the contralateral hemisphere. One group of animals (n = 7) was killed at either 1 or 3 weeks postinjury to assess NSC survival in the acute posttraumatic period. Motor function was evaluated at weekly intervals for 12 weeks in the remaining animals, and cognitive (i.e., learning) deficits were assessed at 3 and 12 weeks after transplantation. RESULTS: Brain-injured animals that received either ipsilateral or contralateral NSC transplants showed significantly improved motor function in selected tests as compared with human embryonic kidney cell-transplanted animals during the 12-week observation period. Cognitive dysfunction was unaffected by transplantation at either 3 or 12 weeks postinjury. Histological analyses showed that NSCs survive for as long as 13 weeks after transplantation and were detected in the hippocampus and/or cortical areas adjacent to the injury cavity. At 13 weeks, the NSCs transplanted ipsilateral to the impact site expressed neuronal (NeuN) or astrocytic (glial fibrillary acidic protein) markers but not markers of oligodendrocytes (2'3'cyclic nucleotide 3'-phosphodiesterase), whereas the contralaterally transplanted NSCs expressed neuronal but not glial markers (double-labeled immunofluorescence and confocal microscopy). CONCLUSION: These data suggest that transplanted NSCs can survive in the traumatically injured brain, differentiate into neurons and/or glia, and attenuate motor dysfunction after traumatic brain injury.     

Comparison of outcomes in elective partial vs radical nephrectomy for clear cell renal cell carcinoma of 4-7 cm

OBJECTIVE: To compare the outcomes of patients who had a elective partial nephrectomy (PN) or radical nephrectomy (RN) for clear cell renal cell carcinoma (RCC) of 4-7 cm. PATIENTS AND METHODS: From March 1998 to July 2004, 45 and 151 patients underwent PN and RN, respectively, for clear cell RCC. A multivariate Cox model was constructed for disease-free survival with adjustment for markers of disease severity, and a propensity-score approach used as a confirmatory analysis. RESULTS: In the PN and RN cohorts the treatment failed in one and 20 patients, respectively; the median follow-up was 21 months. The hazard ratio (95% confidence interval) for PN after adjusting for disease severity was 0.36 (0.05-2.82; P = 0.3). Using planned PN as a predictor (intent-to-treat analysis) the hazard ratio was 1.06 (0.32-3.53; P = 0.9). In the propensity-score model, planned PN was associated with a hazard ratio of 1.75 (0.50-6.14; P = 0.4). The serum creatinine level 3 months after surgery was significantly lower in patients who had PN, with a difference between the means of 0.36 (0.23-0.48; P < 0.001). CONCLUSIONS: Renal function was preserved after PN for 4-7 cm clear cell RCC tumours. When comparing the outcomes of PN and RN it is important to consider the intended operation as an independent variable. There was no clear evidence that PN was associated with worse cancer control, although a continued follow-up of this and other cohorts is warranted.     

In vitro susceptibilities of Escherichia coli isolated from patients with intra-abdominal infections worldwide in 2002-2004: results from SMART (Study for Monitoring Antimicrobial Resistance Trends)

BACKGROUND: Since 2002, the worldwide Study for Monitoring Antimicrobial Resistance Trends (SMART) has tracked resistance patterns among aerobic and facultative gram-negative bacilli isolated from patients with intra-abdominal infections. Escherichia coli has been by far the most frequently isolated species. METHODS: Antimicrobial susceptibilities for consecutive non-duplicate isolates of aerobic and facultative gram-negative bacilli recovered from intra-abdominal infections were determined by standard broth microdilution techniques. A subanalysis was performed for E. coli isolates from the first three years of the study. RESULTS: A total of 7,002 E. coli isolates were recovered, most commonly from the peritoneal cavity followed by the biliary tract. Susceptibility rates to the 12 antimicrobial agents tested differed among geographic regions, with isolates from Asia/Pacific generally having the highest resistance rates. Overall, extended-spectrum beta-lactamase (ESBL)-producers had a more antibiotic-resistant profile than non-ESBL-producers but usually were susceptible to the carbapenems and amikacin. Community-acquired E. coli strains comprised slightly more than one-half of the isolates and were susceptible to the agents tested more frequently than were hospital-acquired E. coli. CONCLUSIONS: The prevalence of antimicrobial resistance among E. coli isolated from intraabdominal infections is not inconsequential, especially in the Asia/Pacific region. The carbapenems and amikacin were consistently active in vitro against E. coli isolates worldwide, including ESBL-producers.