Neural network forecasts of the tropical Pacific sea surface temperatures.

A nonlinear forecast system for the sea surface temperature (SST) anomalies over the whole tropical Pacific has been developed using a multi-layer perceptron neural network approach, where sea level pressure and SST anomalies were used as predictors to predict the five leading SST principal components at lead times from 3 to 15 months. Relative to the linear regression (LR) models, the nonlinear (NL) models showed higher correlation skills and lower root mean square errors over most areas of the domain, especially over the far western Pacific (west of 155 degrees E) and the eastern equatorial Pacific off Peru at lead times longer than 3 months, with correlation skills enhanced by 0.10-0.14. Seasonal and decadal changes in the prediction skills in the NL and LR models were also studied.     

Bone disease in primary biliary cirrhosis: Lack of association with distal renal tubular acidosis

Background and Aims: Primary biliary cirrhosis (PBC) might be complicated by osteoporosis, whose etiology remains unknown but seems to be multifactorial. Prevalence rates of 30% to 60% for distal renal tubular acidosis (DRTA) have been reported in PBC patients, generally as incomplete DRTA. Although it is undisputed that a reduced bone mineral density (BMD) is the expected outcome among patients who have been suffering from longstanding chronic metabolic acidosis, it is unclear if incomplete DRTA is also associated with metabolic bone disease in PBC patients. The present study was undertaken to compare the BMD of PBC patients with and without DRTA.
Methods: The BMD of 23 PBC patients (11 with DRTA and 12 without), all with normal clearance of creatinine, was assessed by dual energy radiograph absorptiometry. The diagnosis of DRTA was made if the urine pH was above 5.4 in all samples after the oral acid overload, showing tubular inability to acidify urine in the presence of test-induced systemic metabolic acidosis.
Results: Densitometric signs of osteoporosis were found in 82% of DRTA cases and in 83% of patients without DRTA (difference not significant). There were no significant differences in BMD measurement, T and Z scores of patients with and without DRTA.
Conclusions: The present study could not support a correlation between the presence of DRTA and the bone loss observed in PBC patients.     

The CLDN5 locus may be involved in the vulnerability to schizophrenia.

The present study was designed to detect three single nucleotide polymorphisms (SNPs) located on 22q11 that was thought as being of particularly importance for genetic research into schizophrenia. We recruited a total of 176 Chinese family trios of Han descent, consisting of mothers, fathers and affected offspring with schizophrenia for the genetic analysis. The transmission disequilibrium test (TDT) showed that of three SNPs, rs10314 in the 3'-untranslated region of the CLDN5 locus was associated with schizophrenia (chi(2) = 4.75, P = 0.029). The other two SNPs, rs1548359 present in the CDC45L locus centromeric of rs10314 and rs739371 in the 5'-flanking region of the CLDN5 locus, did not show such an association. The global chi-square (chi(2)) test showed that the 3-SNP haplotype system was not associated with schizophrenia although the 1-df test for individual haplotypes showed that the rs1548359(C)-rs10314(G)-rs739371(C) haplotype was excessively non-transmitted (chi(2) = 5.32, P = 0.02). Because the claudin proteins are a major component for barrier-forming tight junctions that could play a crucial role in response to changing natural, physiological and pathological conditions, the CLDN5 association with schizophrenia may be an important clue leading to look into a meeting point of genetic and environmental factors.     

A quantitative analysis of valgus torque on the ACL: a human cadaveric study.

The loads needed to elicit a positive pivot shift test in a knee with an anterior cruciate ligament (ACL) rupture have not been quantified. The coupled anterior tibial translation (ATT), coupled internal tibial rotation (ITR), and the in situ force in the ACL in response to a valgus torque, an inherent component of the pivot shift test, were measured in 10 human cadaveric knee specimens. Using a robotic/universal force-moment sensor testing system, valgus torques ranging from 0.0 to 10.0 Nm were applied in nine increments on the intact and ACL-deficient knee in flexion ranging from 0 degrees to 90 degrees. At 15 degrees of knee flexion, the coupled ATT and ITR were significantly increased in the ACL-deficient knee when compared to the intact knee. Coupled ATT increased a maximum of 291% (6.7 mm, p<0.05), while coupled ITR increased a maximum of 85% (5.1 degrees, p<0.05). At 30 degrees, the increases in coupled ATT and ITR were significant at valgus loads of 3.3 Nm and greater with a maximum increase in coupled ATT of 137% (6.3 mm, p<0.05) and a maximum increase in coupled ITR of 38% (3.6 degrees, p<0.05). At 45 degrees, coupled ATT increased significantly (maximum of 69%, 4.4 mm, p<0.05), but only at torques > or =6.7 Nm. The in situ force in the ACL was less than 20 N for all flexion angles when a torque between 3.3 and 5.0 Nm was applied. Low valgus torque elicited tibial subluxation in the ACL-deficient knee with low in situ ACL forces, similar to a positive pivot shift test. Thus, application of a valgus torque may be suitable to evaluate ACL-deficient and ACL-reconstructed knees, since subluxation can be achieved with minimal harm to the ACL graft. This work is important in understanding one load component needed for the pivot shift examination; further studies quantifying other load components are essential for better comprehension of the in vivo pivot shift examination.     

Effect of link protein concentration on articular cartilage proteoglycan aggregation

Previous work has shown that alterations in proteoglycan aggregates are among the first changes detected with aging, disuse, and degeneration of articular cartilage, yet the cause or causes of these alterations remain unknown. To determine if differences in link protein concentration can explain alterations in the assembly, size, and stability of articular cartilage proteoglycan aggregates, we isolated proteoglycan monomer (aggrecan) and link protein from adult bovine articular cartilage and then assembled proteoglycan aggregates from aggrecan and 0.8% hyaluronan relative to aggrecan weight, in the presence of 0, 2, 4, 6, 8, 10, 15, and 20% concentrations of link protein relative to aggrecan weight. We determined the amount, sedimentation coefficient, and stability of the aggregates by analytical ultracentrifugation and measured their dimensions by electron microscopy with use of the monolayer technique. Increased aggregate size, as determined by ultracentrifugation, was directly correlated with an increased number of aggrecans per aggregate and with increased hyaluronan length, as determined by electron microscopy. The concentration of link protein significantly influenced aggregation: concentrations of 6–8% produced maximum aggregation, aggregate stability, and uniformity of aggrecan spacing; concentrations greater than 10% led to the formation of superaggregates (aggregates with sedimentation velocities greater than 100 S that may result from linking two or more hyaluronan filaments) but decreased aggregate stability; and concentrations of less than 4% link protein significantly decreased aggregation, the size and stability of aggregates, and the regularity of aggrecan spacing. The latter observations suggest that a decline in the concentration of link protein could decrease the organization and stability of the articular cartilage matrix.     

颈椎骨折类型与脊髓损伤关系之临床观察

通过对９２例颈椎骨折病例的分析，发现屈曲型损伤最多见（５３％），其次为过伸型（２６％），压缩型（２１％）。屈曲型和压缩型多见于年轻人，而屈曲损伤导致的脱位及过伸型则多见于年龄较大者。爆裂骨折引起的神经损害最重，其次为屈曲型、过伸型及压缩（非爆裂）骨折。神经功能改善率以爆裂型骨折最差，死亡率亦最高，以压缩（非爆裂型）骨折最好，其次为过伸型及屈曲型。文内对各型的特点进行了详细讨论。