Rapid changes in the expression of a gene encoding a calcium-binding protein in Schistosoma mansoni

Genes expressed in a stage-specific manner may help us understand the molecular events controlling the complex life cycle of schistosomes. cDNA and genomic clones encoding a calcium-binding protein (CaBP) were obtained from cercariae and their sequence determined. The encoded protein (69 amino acids long) shows clear resemblance to the domain structure and organization of CaBP molecules. It contains two typical calcium-binding loops, the distance between which is identical to the length conserved in other CaBP molecules. In addition, the schistosome CaBP shows Ca2+-dependent electrophoretic mobility (increased with Ca2+-ions and decreased with EGTA). Northern blots revealed expression of the CaBP gene in cercariae but not in sporocyst or worm (developmental stages preceding and following cercaria). The preferential expression of this CaBP in the cercaria raises questions as to what cercaria-specific function(s) it performs. The structure of the gene is similar to that in other eukaryotes, and one intron interrupts the coding sequence. The region of the cap site was determined, and there was no evidence of the spliced leader sequence found in the mRNAs of other parasites. The CaBP reveals a rapid change in gene expression, since the mRNA is missing in the parasite residing in infected snails, but is readily detected in cercariae 1 h after shedding. We identified other genes which are turned on (like the CaBP) or shut off within the short period of transition from cercariae in the snail to free-swimming cercariae.     

Immunoregulatory properties of the proteins present in human milk

The immunoregulatory properties of several proteins, isolated from human milk, were investigated. Secretory component and galactothermin exhibited immunoregulatory activities in the in vivo and in vitro assays, generating helper cells, changing the ARFC levels and the resistance of thymocytes to hydrocortisone (HC). In addition, the immunoregulatory action of the P protein and its four fractions was studied. The bulk of the activity was found in the fraction II and III. The results suggest that the postneonatal development of the mammalian immune system is under the surveillance of various immunoregulatory proteins contained in maternal secretory fluids.     

Osteoinductivity and biomechanics of a porous ceramic with autogenic periosteum

Twenty-one dogs were used to study the osteoinductivity and biomechanical properties of a biphasic porous ceramic with autogenic periosteum implanted in muscle. The ceramic implants were swathed in fresh periosteum derived from the same animals and implanted in the femur muscles. The other two groups of animals served as controls using the same material implanted in the femur bones and muscles without periosteum. Biomechanical measurements showed that, in the muscles, the experimental group had a higher bending strength than the unswathed group by the time the samples were harvested. Six months postoperatively, the strength of the samples in the experimental group had almost reached that of normal bones. The results of X-ray diffraction and infrared spectrometric analysis suggested that the degradation rate and speed of tricalcium phosphate (TCP) of the ceramic in the experimental group were faster than in the unswathed samples, but slower than in samples implanted in bones. The bone replacement and bone-inducing activity were excellent in the periosteum-swathed samples. Histologically, satisfactory bone repair was seen in the experimental samples. All results indicate that autogenic periosteum could increase bioactivity of ceramics in heterosites and improve bone formation in the surroundings of porous calcium phosphate ceramics. The data also infer that the complicated procedure of culturing bone growth factors with biomaterials in vitro to obtain bioactive grafts could be replaced by this relatively simple method.     

Medical library education in China

This paper describes the establishment of faculties of medical library and information science in four of the national medical universities in the People's Republic of China. These faculties were established in the mid-1980s, and each is fully integrated into its university. Students receive three years of non-clinical medical training followed by two years of training in library and information science. The first students to follow this five-year curriculum will graduate in 1992.     

The mechanism of the effect of the posterior root ganglia on smooth muscle

Summary The posterior roots of the lumbar and sacral regions of the dog spinal cord were stimulated, and the effect on the smooth muscle of the urinary bladder and m. retractor penis found. The wall of the bladder contracted and the m. retractor penis relaxed. The reaction was intensified by eserine but was not affected by cocaine. Therefore, acetylcholine plays a significant part in the action of the posterior roots on these muscles.(Presented by Active Member AMN SSSR U. V. Parin) Translated from Byulleten Èksperimental'noi Biologii i Meditsiny Vol. 49, No. 4, pp. 12–14, April, 1960     

Relationship of pili to colonial morphology among pathogenic and nonpathogenic species of Neisseria.

Growth in colonies with type 1 morphology and the presence of pili are characteristics that have been associated with virulence of gonococci for humans. To determine whether the presence of pili per se might be responsible for colony type 1 morphology, the relationship of pili to colony type was examined in various species of Neisseria. Short pili (175 to 210 nm in length) were seen only on nonpathogenic neisseria, whereas long pili (up to 4,300 nm) were seen on organisms of both nonpathogenic and pathogenic species. Although long pili, similar to those found on organisms from high-domed, type 1 colonies of gonococci, were observed on organisms from high-domed, type 1 colonies of nonpathogenic Neisseria species, they were also observed on low-convex, type 4 colonies of meningococci and nonpathogenic neisseria. Among meningococci there was no difference in the morphology of colonies consisting of organisms with many long pili and colonies consisting of organisms that completely lacked pili. Thus, there was no consistent relationship of pili to colonial morphology. Unless the pili of N. gonorrhoeae are unique among Neisseria species in their influence on colonial morphology, it is likely that factors other than pili determine colony type 1 morphology of gonococci. Whether these same factors, either alone or in conjunction with pili, are also responsible for gonococcal virulence warrants further investigation.     

Quantitative real-time PCR detection of adenovirus in clinical blood specimens: A comparison of plasma, whole blood and peripheral blood mononuclear cells

BACKGROUND: Detection and quantification of adenovirus (ADV) in peripheral blood specimens has become an increasingly important tool in the management of immunosuppressed patients. Investigators have described the use of whole blood (WB), peripheral blood mononuclear cells (PBMC), serum and plasma but no studies have compared the utility of these different sample types for use in a clinical diagnostic assay. OBJECTIVES: To determine the optimal blood compartment for quantitative real-time measurement of adenovirus in peripheral blood specimens. STUDY DESIGN: WB, PBMC, and plasma representing 338 samples from 148 patients were tested for ADV by quantitative real-time PCR (qrt-PCR) and the results compared for concordance of both qualitative sensitivity and viral load among positive specimens. RESULTS: There was no significant difference in qualitative sensitivity among the three tested specimen types. Quantitative values of WB and plasma were similar and tended to be greater than those found in PBMC samples. Comparison of consecutive positive samples within individual patients showed that viral loads tracked similarly over time, irrespective of the sample type tested. CONCLUSION: While WB and plasma do not offer a significant increase in sensitivity over PBMC, they may offer benefits in terms of reduced processing costs and laboratory turn around time.     

少枝胶质细胞瘤的形态观察

目的研究少枝胶质细胞瘤（ＯＤＧ）的超微结构及组织学特性。方法用光镜，部分用电镜及免疫组化观察６５例ＯＤＧ。结果根据ＷＨＯ有关ＯＤＧ病理分级，６５例中Ⅰ级１９例，Ⅱ级３２例，Ⅲ级１４例。结论ＯＤＧ中瘤细胞出现胶质微丝是异质性分化的结果。除按瘤细胞分化程度分级外，细胞密度、核分裂数亦有重要意义。