A Multilocus Genotypic Analysis of Cryptosporidium meleagridis

ABSTRACT. Cryptosporidium meleagridis is a common cause of cryptosporidiosis in birds. In addition, recent reports have described the parasite as an etiologic agent of cryptosporidiosis in both immunocompetent and immunocompromised humans. Therefore, it is important to genetically characterize isolates of C. meleagridis from different hosts and geographic areas, and to develop molecular tools to differentiate isolates from various hosts or areas. In this study, a total of 11 isolates of Cryptosporidium meleagridis from both human and avian hosts were examined at three genetic loci: the small-subunit rRNA, 60-kDa glycoprotein precursor, and 70-kDa heat shock protein genes. Two genotypes of C. meleagridis were seen at the small-subunit rRNA locus. These differed from each other by the presence or lack of a heterogeneous copy of the gene and an ATT repeat. The 60-kDa glycoprotein precursor gene divided these eleven isolates of C. meleagridis into six genotypes with high sequence diversity between groups. The highest genetic heterogeneity, however, was seen at the 70-kDa heat shock protein locus, and was primarily present at the 3'end of the gene. This heterogeneity separated eight isolates of C. meleagridis into six genotypes. These data could be useful in the development of molecular tools to promote understanding of the transmission of C. meleagridisi in humans.     

肽核酸在基因诊断和治疗中的研究进展

肽核酸是一种以多肽为骨架,类似核苷酸的物质。它不带电荷,能抵抗核酸酶和蛋白酶的降解;它与DNA或RNA杂交特异性很强,可与靶基因形成稳定的三螺旋结构。肽核酸能够抑制基因的复制、转录、逆转录和翻译过程,在基因诊断及治疗方面有着广泛的用途。     

Spatial heterogeneity in a grassland community: Use of power law

A new regression analysis was proposed to evaluate the degree of spatial heterogeneity for individual species comprising a plant grassland community. The weighted average of the heterogeneity value of all the species comprising the community provides a measure of community-level heterogeneity. A field survey was carried out, as an example, in order to analyze the spatial heterogeneity of a pasture with grazing cows, using 100 quadrats 50 cm × 50 cm, each of which was divided into four smaller quadrats 25 cm × 25 cm, on a 50 m long line-transect. The frequency of occurrence for all the species in each small quadrat was recorded. The regression associated with the ratio of the theoretical and observed variances of occurence counts was used to analyse the frequency distribution of species in a pasture community. A good fit to the regression for the whole community was obtained. These results indicate that (i) each species in the example was distributed more heterogeneously than a random pattern; and (ii) the regression could well describe the spatial heterogeneity of the grassland plant community. In most of the observed species, spatial heterogeneity is often characterized by species-specific propagation traits and the architecture of plant bodies. Thus, the spatial patterns of a grassland community can be evaluated in detail by this power-law approach. This measure is suitable for field surveys and comparative studies of grassland communities, and for other plant communities that are generally short in height.     

Distinguishing malignant from normal oral tissues using FTIR fiber-optic techniques

Oral tissue samples were studied using mid-IR fiber-optic attenuated total reflectance spectroscopy and other spectral techniques. The 1745 cm(-1) band, which is assigned to the ester group (C==O) vibration of triglycerides, is a reliable marker that is present in normal tissues but absent or a weak band in malignant oral tissues. Other bands such as C--H stretching bands and the amide bands are also helpful in distinguishing malignant tissues from normal tissues. Subtraction spectra confirmed the above conclusion. In addition, Raman spectroscopic measurements were in agreement with the results observed from FTIR spectra.     

Effect of unionized ammonia,viscosity and protozoan contamination on reproduction and enzyme activity of the rotifer Brachionus rotundiformis

We determined the effect of environmental stressors on the physiological condition of Brachionus rotundiformis. For two morphologically distinct B. rotundiformis strains: Hawaii (average lorica length = 222 m) and Langkawi strains (average lorica length 180 m), neonates hatched from resting eggs were exposed to different levels of unionized ammonia (0.7–9.8 mg l^–1), viscosity (relative viscosity against natural seawater = 1–1.17) and Euplotes sp. (protozoan) contamination (1–40 cells ml^–1). Increasing stress decreased fecundity and lifespan of both rotifer strains. Glucosidase and phospholipase activities were correlated with reproductive responses of both the strains exposed to unionized ammonia. When culture water viscosity was changed, the activity of esterase and phospholipase was correlated with reproductive responses of the Hawaiian strain, and glucosidase activity was correlated with those of Langkawi strain.With the protozoan contamination, esterase and glucosidase activities were correlated only with reproductive responses of the Hawaiian strain, while activity of all three enzymes was correlated to those of the Langkawi strain. Glucosidase activity proved to be a reliable indicator of stress for cultured B. rotundiformis.     

Immunodiagnosis of childhood malignancies

Immunodiagnosis utilizing immunohistochemical techniques is currently the most commonly utilized and readily available method of ancillary diagnosis in pediatric oncopathology. The methodology comprises relatively simple steps, based on straightforward biologic concepts, and the reagents used are generally well characterized and widely used. The principle of cancer immunodiagnosis is based on the determination of neoplastic lineage using detection of proteins typical of cell differentiation pathways. Methodology sensitivity varies and has become greater with each new generation of tests, but technical drawbacks should be considered to avoid excessive background or nonspecific results. Automated instrumentation offers a degree of accuracy and reproducibility not easily attainable by manual methods.     

Sertoli-Leydig cell tumor - a rare androgen secreting ovarian tumor in postmenopausal women. Case report and review of literature

Sertoli-Leydig cell tumors (SLCT) constitute only 1-0.5% of all primary ovarian neoplasms. We report a SLCT in a postmenopausal woman aged 69 years. The physical examination revealed severe hirsutism. Basal hormonal evaluation showed high plasma testosterone and estradiol values, with suppressed plasma gonadotropins. Computer tomograph scan revealed a right ovarian tumor mass of 4,3/3 cm, confirming an androgen secreting ovarian tumor. The histopathological and immunocytochemical examination established the diagnosis of well differentiated Sertoli-Leydig cell tumor. The tumor was positive for cytokeratin KL 1 and S-100 protein and, in isolated tumor cells, positive for alpha-fetoprotein. Postsurgical evolution was favorable; controls after 6 months and 3,5 years showed marked reduction of hirsutism, normal plasma testosterone values and gonadotropins in normal postmenopausal range. We discuss the complex aspects of etiology and pathogenesis, the clinical and hormonal settings, the role of immunocytochemical markers in diagnosis, as well as the therapy and the prognostic features of this ovarian tumor.     

Molecular pathology in the diagnosis and treatment of non-Hodgkin's lymphomas

The non-Hodgkin's lymphomas encompass a wide spectrum of hematologic neoplasms that exhibit different clinical and biological features. Lymphomas classically have been initially assessed based on their cytologic and histologic features. Morphology alone is often inadequate as similar appearing neoplasms may be immunophenotypically and molecularly heterogeneous. Molecular diagnostic methods can provide an additional level of testing that not only helps refine diagnoses but can provide prognostic information. New methods are being refined that may provide information to establish precise diagnostic profiles, provide targets for therapy and provide more sensitive methods for monitoring the success of treatment. Molecular methods will be increasingly utilized and eventually required as the accepted method of diagnosis and for monitoring the disease. Understanding of the molecular abnormality and the pathogenesis of the neoplasm hopefully will lead to therapeutic intervention aimed at the specific molecular defect or its product. The molecular pathology of the non-Hodgkin's lymphomas is discussed.     

Evaluation and evolution during time of prenatal diagnosis of congenital heart diseases by routine fetal ultrasonographic examination

The objectives of this study were to evaluate routine prenatal diagnosis of congenital heart diseases (CHD) by fetal ultrasound examination in a well-defined population during the period 1994-1999 and to compare these results with the results from 1979 to 1993. This study included 80,076 consecutive pregnancies of known outcome from 1994 to 1999. CHD were classified as isolated or associated when at least one other major extra-cardiac malformation was present. Only 137 out of 688 malformed fetuses with CHD without chromosomal anomalies were detected (19.9%). The sensitivity of detection varied from 61.9% for malformations such as isolated hypoplastic left heart and single ventricle, to around 7-19% for atrial and ventricular septal defects. Prenatal detection rate of CHD was 11.4% for isolated cases, and 40.2% for multiple malformed with CHD. The gestational age at discovery varied from 16 to 36 weeks. There is no upper limit for termination of pregnancies in our country; 12.3% of all pregnancies were terminated after prenatal diagnosis. However, 62% of the pregnancies with a CHD detected prenatally were terminated. The detection rate of CHD increased during time from 9.2% during the period 1979-1988 to 13.7% during the period 1990-1993 and to 19.1% during the period 1994-1999. Our study shows large variation in the prenatal detection rate of CHD. Prenatal diagnosis of CHD is significantly higher when associated malformations are present. Cardiac defects affecting the size of the ventricles have the highest detection rate. Gestational age at discovery was 20-24 weeks for the majority of associated cardiac defects. The prenatal detection rate of CHD increased during time from 1979 to 1999.     

Morphology and infraciliature of a new marine ciliate Euplotidium smalli n. sp. with description of a new genus,Paraeuplotidium n. g. (Ciliophora,Euplotida)

The morphology and infraciliature of a new hypotrichous ciliate, Euplotidium smalli n. sp., isolated from eutrophic coastal water in Korea, were observed in living cells and investigated using the protargol impregnation technique. This new ciliate bears 13-14 frontoventral cirri, 7 transverse cirri, and 5-6 dorsal kineties. Neither left marginal cirrus nor caudal cirrus is present. The new species differs from the related species, Euplotidium agitatum Noland, 1937 in the different number of frontoventral and transverse cirri and different body shape. With the exception of Euplotidium agitatum, the known species of the genus Euplotidium Noland, 1937 with the presence of left marginal cirrus are assigned to a new genus, Paraeuplotidium n. g. Diagnosis of Paraeuplotidium is: Gastrocirrhidae with funnel-shaped buccal cavity; with frontoventral and transverse cirri; left marginal cirrus present. Paraeuplotidium itoi (Ito, 1958) n. comb. is designated here the type species. Four additional species are included: Paraeuplotidium psammophilus (Vacelet, 1961) n. comb., Paraeuplotidium arenarium (Magagnini & Nobili, 1964) n. comb., Paraeuplotidium helgae (Hartwig, 1980) n. comb., and Paraeuplotidium prosaltans (Tuffrau, 1985) n. comb. An improved generic diagnosis of Euplotidium is suggested based on morphology and infraciliature characters: marine hypotrichs with a funnel-shaped buccal cavity; with frontoventral and transverse cirri; neither left marginal cirrus nor caudal cirri present.