Recruitment of functional GABA(A) receptors to postsynaptic domains by insulin

Modification of synaptic strength in the mammalian central nervous system (CNS) occurs at both pre- and postsynaptic sites. However, because postsynaptic receptors are likely to be saturated by released transmitter, an increase in the number of active postsynaptic receptors may be a more efficient way of strengthening synaptic efficacy. But there has been no evidence for a rapid recruitment of neurotransmitter receptors to the postsynaptic membrane in the CNS. Here we report that insulin causes the type A gamma-aminobutyric acid (GABA[A]) receptor, the principal receptor that mediates synaptic inhibition in the CNS, to translocate rapidly from the intracellular compartment to the plasma membrane in transfected HEK 293 cells, and that this relocation requires the beta2 subunit of the GABA(A) receptor. In CNS neurons, insulin increases the expression of GABA(A) receptors on the postsynaptic and dendritic membranes. We found that insulin increases the number of functional postsynaptic GABA(A) receptors, thereby increasing the amplitude of the GABA(A)-receptor-mediated miniature inhibitory postsynaptic currents (mIPSCs) without altering their time course. These results provide evidence for a rapid recruitment of functional receptors to the postsynaptic plasma membrane, suggesting a fundamental mechanism for the generation of synaptic plasticity.     

Identification of genes expressed in human CD34(+) hematopoietic stem/progenitor cells by expressed sequence tags and efficient full-length cDNA cloning

Hematopoietic stem/progenitor cells (HSPCs) possess the potentials of self-renewal, proliferation, and differentiation toward different lineages of blood cells. These cells not only play a primordial role in hematopoietic development but also have important clinical application. Characterization of the gene expression profile in CD34(+) HSPCs may lead to a better understanding of the regulation of normal and pathological hematopoiesis. In the present work, genes expressed in human umbilical cord blood CD34(+) cells were catalogued by partially sequencing a large amount of cDNA clones [or expressed sequence tags (ESTs)] and analyzing these sequences with the tools of bioinformatics. Among 9,866 ESTs thus obtained, 4,697 (47.6%) showed identity to known genes in the GenBank database, 2, 603 (26.4%) matched to the ESTs previously deposited in a public domain database, 1,415 (14.3%) were previously undescribed ESTs, and the remaining 1,151 (11.7%) were mitochondrial DNA, ribosomal RNA, or repetitive (Alu or L1) sequences. Integration of ESTs of known genes generated a profile including 855 genes that could be divided into different categories according to their functions. Some (8.2%) of the genes in this profile were considered related to early hematopoiesis. The possible function of ESTs corresponding to so far unknown genes were approached by means of homology and functional motif searches. Moreover, attempts were made to generate libraries enriched for full-length cDNAs, to better explore the genes in HSPCs. Nearly 60% of the cDNA clones of mRNA under 2 kb in our libraries had 5' ends upstream of the first ATG codon of the ORF. With this satisfactory result, we have developed an efficient working system that allowed fast sequencing of 32 full-length cDNAs, 16 of them being mapped to the chromosomes with radiation hybrid panels. This work may lay a basis for the further research on the molecular network of hematopoietic regulation.     

Oxidized low-density lipoproteins induce apoptosis in macrophages

OBJECTIVE: We wished to determine if timing of surgery, when other co-morbid variables are controlled, influenced outcome after operations for acute myocardial infarction. DESIGN: Between 3/20/1990 and 6/17/1994, data was prospectively collected on 338 patients undergoing operation for either evolving infarcts (n=73) or up to 21 days after infarction (mean 7.9 days). SETTING: Tertiary hospital referral center. PATIENTS: Infarction was diagnosed by CK enzymes or EKG Q-waves preoperatively in 338 patients undergoing surgery. The mean age of the patients was 66.1 years (SD+/-10.5 years), 76 had emergency operations immediately after catheterization (50 following PTCA complications), 223 had urgent operations, and 39 were elective. INTERVENTIONS: Seventy-three had preoperative ballon pumps, and 259 had one or more mammary artery bypasses with a mean of 3.27 (SD+/-1.0) distal anastomoses. RESULTS: In-hospital and 30-day survival rate was 95.6% (323/338). Of the 73 variables evaluated by step-wise logistic regression analysis, the multivariate independent preoperative predictors of death were: aortic valve regurgitation, chronic pulmonary disease, preoperative diuretic administration, preoperative balloon pump, preoperative inotropes, and the need for additional concomitant noncardiac surgery. Including the operative variables, the predictors were: preoperative balloon pump, preoperative inotropes, the presence of left main stenosis, preoperative renal failure, chronic pulmonary disease, valve disease, ischemic arrhythmia, pump perfusion time, valve surgery, and homologous blood transfusion volume required. When the postoperative variables were included, the predictors were: preoperative inotropes, postoperative balloon pump, postoperative epinephrine, postoperative permanent stroke, and postoperative acute renal failure. The time between infarction and operation was not an independent prediction (p>0.4) in any of the logistic regression models. CONCLUSION: Early operation after acute infarction is not in itself a risk factor, rather comorbid disease and preoperative hemodynamic status determine outcome after surgery.     

高含盐油藏注水吞吐提高单井采油量探讨

中原油田Ａ油藏属于小断块，低孔，低渗高含盐特殊油藏。由于原油中含盐，地水矿化度高，在开采过程中地层结盐造成孔隙堵塞，渗透性变差。开采过程中由于掺水化盐、井筒结垢严重影响正常生产。通过注水吞吐试验，解决了地层盐堵，疏通了地层孔隙，改善了地层的渗透性，减少了井筒结垢，提高了油井产油量。     

Intraoperative radiotherapy of unresectable pancreatic carcinoma

During the period from 1986 to 1991, 33 patients with unresectable carcinoma of the pancreas received intraoperative radiotherapy (IORT). Abdominal and back pain which tormented all patients before IORT totally disappeared in 18 patients (54%) and was allevrited in 13 patients (40%). The average survival time of 6.5 months for patients treated with IORT was not statistically different from that of 30 patients with resectable pancreatic cancers undergoing resection. IORT hence is a good palliative therapy for unresectable carcinoma of the pancreas.