Acute respiratory distress syndrome: CT abnormalities at long-term follow-up

Photochemical thrombotic ischemia model was used to study the possible roles of excision repair cross-complementing group 6 (ERCC6), a DNA repair gene, in the neuroprotection of dextromethorphan (DM), a NMDA antagonist, in ischemic brain injury. The results showed that no obvious ERCC6 mRNA expression was found in the perifocal area of irradiated cerebral cortex before 24 h postischemia. Then, the number of ERCC6 mRNA positive cells gradually enhanced, and attained a peak value at 72 h after light irradiation, which followed a declined tendency at 7-day postlesion. These results suggest that DNA repair gene ERCC6 mRNA expression in the perifocal area may be involved in the pathophysiological processes following the photochemical thrombotic cerebral ischemia. By the administration of DM, we observed that it can significantly upregulate the expression of ERCC6 mRNA in the perifocal area at 48 h after ischemic event. The neuroprotective mechanisms of DM may be related to the upregulation of DNA repair gene ERCC6 mRNA.     

Articular cartilage superficial zone protein (SZP) is homologous to megakaryocyte stimulating factor precursor and Is a multifunctional proteoglycan with potential growth-promoting, cytoprotective, and lubricating properties in cartilage metabolism

We have performed cDNA sequencing and homology analyses to elucidate the complete amino acid composition for a superficial zone protein (SZP) from human and bovine cartilage which has previously been shown to be a proteoglycan specifically synthesized by chondrocytes located at the surface of bovine articular cartilage and also some synovial lining cells. The results of this study indicate that cartilage SZP is homologous with a glycoprotein first described as the precursor protein of a megakaryocyte stimulating factor (MSF). Sequence comparisons and analyses indicate that (i) the amino acid composition of SZP is highly conserved between bovine and human species, (ii) SZP contains structural motifs at the N- and C-termini which are similar to those found in vitronectin and which may impart cell-proliferative and matrix-binding properties to the molecule, and (iii) SZP contains large and small mucin-like repeat domains composed of the sequences KEPAPTTT/P (76-78 repeats) and XXTTTX (6-8 repeats), respectively, which occur within a large central region of approximately 940 amino acids. The mucin-like domains are likely to be substituted with O-linked oligosaccharides which would impart lubricating properties to SZP which in part accumulates at the articular cartilage-synovial fluid interface. Additionally, we have shown that interleukin-1 inhibits the biosynthesis of chondrocyte SZP, while TGF-beta and IGF-1 increase its biosynthesis, and that in pathological (osteoarthritic) human articular cartilage SZP mRNA can be expressed as an alternatively spliced variant lacking exons 4 and 5 which encode a potential heparin binding domain. The occurrence of different SZP alternative splice variants and the differential expression of SZP in the presence of cytokines and growth factors suggest that SZP may play an important cytoprotective role by preventing cellular adhesion to the articular cartilage surface in normal cartilage metabolism. Modifications to the structure of SZP, coupled with inhibition of SZP synthesis during inflammation, may account for the attachment and invasion of pannus observed in inflammatory joint diseases.     

Differences in reproductive characteristics among field populations of Polycelis tenuis (Platyhelminthes) in a metal contaminated stream

The unlabeled (cold) minimal model (MM) and the labeled (hot) minimal model (HMM) are a powerful tool to investigate in vivo metabolism from a standard intravenous glucose tolerance test (IVGTT) or hot IVGTT (HIVGTT). They allow to estimate metabolic indexes of the glucose-insulin system, namely glucose effectiveness (GE) and insulin sensitivity (IS) (of uptake and production those of MM, and of uptake only those of HMM). Here, the consequences of the single-compartment glucose kinetics approximation used in the MM's are investigated via Monte Carlo simulation, using a physiologic reference model (RM) of the system. RM allows to generate noisy synthetic plasma concentrations of glucose, tracer glucose, and insulin during IVGTT and HIVGTT, which are then analyzed with MM and HMM. The MM and HMM GE and IS are then compared with the RM ones. Results of 400 runs show that: 1) correlation of MM GE with the RM index is weak; 2) MM IS is well correlated with the RM index, but severely underestimates it; 3) HMM clearance rate is correlated with RM clearance; and 4) HMM IS is well correlated and only slightly overestimates the RM index. These results demonstrate that GE of MM is most affected by the single-compartment approximation and the indexes of HMM are more robust than those of MM.     

Stimulation of ammonia production and excretion in the rabbit by inorganic phosphate. Study of control mechanisms

The purpose of this study was to clarify the mechanism (s) responsible for regulation of ammonia production and excretion in the rabbit. The normally low ammonia excretion rate during acute metabolic acidosis was stimulated acutely and increased approximately ninefold after infusion of sodium phosphate, but remained low if sodium sulphate or Tris was substituted for phosphate. Ammonia production was increased significantly by phosphate in rabbit renal cortex slices and in isolated renal cortex mitochondria. In isolated mitochondria, mersalyl, an inhibitor of both the phosphate/hydroxyl and phosphate/dicarboxylate mitochondrial carriers, inhibited the phosphate-induced stimulation, indicating that phosphate must enter the mitochondrion for stimulation. A malate/phosphate exchange seemed to be involved since N-ethylmaleimide, an inhibitor of the phosphate/hydroxyl exchange, did not inhibit phosphate-stimulated ammonia production, whereas there was inhibition by 2-n-butylmalonate, a competitive inhibitor of the dicarboxylate carrier. Phosphate itself was not essential since malonate stimulated ammoniagenesis in the absence of added phosphate. Similarly, citrate stimulated ammoniagenesis in isolated mitochondria in the absence of inorganic phosphate provided that it induced L-malate exit on the citrate transporter associated with inhibition of citrate oxidation by fluoroacetate. Similar results were also seen in mitochondria from rat renal cortex. A fall in mitochondrial alpha-ketoglutarate level resulted in an increase in ammonia production. This could be achieved directly with malonate or indirectly via L-malate exit. Simultaneous measurements of glutamate showed that the rate of ammonia production was reciprocally related to the glutamate content. We conclude that phosphate-induced stimulation of ammoniagenesis in the rabbit kidney is mediated by removal of glutamate, the feedback inhibitor of phosphate-dependent glutaminase. Glutamate removal is linked to phosphate-induced dicarboxylate exit across the mitochondrial membrane.     

Cluster headache is an inherited disorder in some families

We investigated the familial occurrence of cluster headache in 370 probands with cluster headache, diagnosed according to the operational diagnostic criteria of the international Headache Society. Seven probands belonged to three families. A positive family history of cluster headache was found in 7% (25 of 366) of the families. Compared with the general population, the first- and second-degree relatives of the 370 probands with cluster headache had a 14- and 2-fold increased risk of having cluster headache, after standardization for sex and age. This increased familial risk strongly suggests that cluster headache has a genetic cause. The patterns of segregation were assessed by complex segregation analysis performed with the computer program, POINTER. The segregation analysis suggests that cluster headache has an autosomal dominant gene with a penetrance of 0.30 to 0.34 in males and 0.17 to 0.21 in females. The gene is present in 3% to 4% of males and 7% to 10% of females with cluster headache.     

Risk of recurrent biliary tract disease after cholecystectomy in patients with duodenal diverticula

OBJECTIVE: To determine if the presence of duodenal diverticula predisposes to the development of common bile duct stones. DESIGN: Cohort study; median follow-up, 10.0 years (25th and 75th percentiles, 5.2 and 16.1 years, respectively). SETTING: Tertiary care center. PATIENTS: One hundred fifty-seven patients with radiologically diagnosed duodenal diverticula who had undergone cholecystectomy from 1950 through 1987 and were asymptomatic at the initiation of follow-up. MAIN OUTCOME MEASURES: All patients were followed up for evidence of recurrent biliary tract disease to the following end points: (1) evidence of choledocholithiasis demonstrated by radiologic surgical, or biochemical means and (2) clinical or biochemical evidence of biliary pancreatitis. RESULTS: Of the 157 patients in the study cohort, 13 patients were categorized as having had recurrent biliary tract disease. Using the Kaplan-Meier survivorship method, the cumulative probabilities of recurrent biliary tract disease in patients with radiologically diagnosed duodenal diverticula were 3.6% at 5 years (95% confidence interval, 0.5-6.9), 5.5% at 10 years (95% confidence interval, 1.5-9.4), and 10.2% at 15 years (95% confidence interval, 3.8-16.7). Age, common bile duct exploration and choledochotomy, and the presence of common bile duct dilatation were not found to be significantly associated with recurrence based on a univariate analysis of risk factors by means of the log-rank statistic. CONCLUSIONS: For patients with radiologically diagnosed, second-portion duodenal diverticula, the risk of developing recurrent bile duct stones after cholecystectomy is lower than has been suggested in previous studies. In the absence of concurrent choledocholithiasis, sphincterotomy or biliary bypass at the time of cholecystectomy seems unwarranted.