Biologically relevant effects of mRNA amplification on gene expression profiles

Background  

Gene expression microarray technology permits the analysis of global gene expression profiles. The amount of sample needed limits the use of small excision biopsies and/or needle biopsies from human or animal tissues. Linear amplification techniques have been developed to increase the amount of sample derived cDNA. These amplified samples can be hybridised on microarrays. However, little information is available whether microarrays based on amplified and unamplified material yield comparable results.     

不同放牧强度下短花针茅荒漠草原植被的空间异质性

分析不同放牧强度下植物群落中物种的空间分布特征, 有助于阐明群落在放牧胁迫下的演替规律。该研究基于幂函数法则, 探讨了不同放牧强度下短花针茅(Stipa breviflora)荒漠草原群落植物的频率和空间异质性。结果表明: 不同放牧强度下物种空间分布与幂函数法则能很好地吻合; 不同物种空间异质性具有特异性, 随着放牧强度的增加, 提高群落空间异质性的物种分别由无芒隐子草(Cleistogenes songorica)、冷蒿(Artemisia frigida)、短花针茅、银灰旋花(Convolvulus ammannii)等多个物种逐渐转变为以无芒隐子草、短花针茅为主的少数物种, 同时, 物种空间异质性大于群落空间异质性的物种数逐渐减少。     

Neanderthal parietal, vertebrate fauna, and stone artifacts from the Upper Pleistocene deposits of Contrada Ianní di San Calogero (Catanzaro, Calabria, Italy)

Human skeletal remains recovered at a new archaeological site, dating back to the Italian Mousterian age are analyzed. The finds consist of a left parietal of a child about 2-3 years old. The metrical, morphometrical, and morphological traits of this parietal are compared to those of other Neanderthal children. The geological features of the site, its fauna, and stone artifacts recovered there during quarry operations are also analyzed.     

Amblyomma sculptum: genetic diversity and rickettsias in the Brazilian Cerrado biome

Amblyomma sculptum (Ixodida: Ixodidae) Berlese, 1888 is the most important tick vector in Brazil, transmitting the bioagent of the most severe form of spotted fever (SF) in part of the Cerrado (in the states of Minas Gerais and São Paulo). In another part of the Cerrado (Central‐West region of Brazil), a milder form of SF has been recorded. However, neither the rickettsia nor the vector involved have been characterized. The aim of the current study was to analyse genetic variation and the presence of rickettsia in A. sculptum in Cerrado, from silent areas and with the milder form of SF. Samples were subjected to DNA extraction, amplification and sequencing of 12S rDNA, cytochrome oxidase subunit II and D‐loop mitochondrial genes (for tick population analyses), and gltA, htrA, ompA and gene D (sca4) genes for rickettsia researches. Exclusive haplotypes with low frequencies, high haplotype diversity and low nucleotide diversity, star‐shaped networks and significant results in neutrality tests indicate A. sculptum population expansions in some areas. Rickettsia amblyommatis, Candidatus Rickettsia andeanae and Rickettsia felis were detected. The A. sculptum diversity is not geographically, or biome delimited, pointing to a different potential in vector capacity, possibly associated with differing tick genetic profiles.     

Characterization of sodium transport in gustatory epithelia from the hamster and rat

The transduction of sodium salts occurs through a variety of mechanisms, including sodium influx through amiloride-sensitive sodium channels, anion-dependent sodium movement through intercellular junctions and unidentified amiloride-insensitive mechanisms. Characterizations of sodium transport in lingual epithelium mounted in Ussing chambers have focused almost exclusively on epithelia containing only fungiform taste buds. In the present study we have investigated sodium transport by measuring NaCl-induced short-circuit current from lingual epithelia containing fungiform, foliate, vallate and palatine taste buds in the hamster and the rat. All areas show measurable sodium transport, yet significant differences were noted between the epithelia from the rat and the hamster and among the different epithelia within a single species in terms of current density, transepithelial resistance and mucosal amiloride sensitivity. In general, epithelia from the anterior tongue were of a lower resistance and transported sodium more effectively than from the posterior tongue. Moreover, fungiform- and vallate-containing epithelia in the rat had a greater current density than did the corresponding tissues in the hamster. Amiloride sensitivity also differed between the rat and the hamster. In the hamster all gustatory areas showed some amiloride sensitivity, while in the rat the vallate-containing epithelia were devoid of amiloride- sensitive sodium transport. The results are consistent with the interpretation that all chemosensitive areas may participate in the detection of salts but the degree of salt transport and the mechanism of transport is variable among different lingual epithelia and different species.      

Quality assurance in cytopathology. Recommendations and ongoing quality assurance activities of the American Society of Clinical Pathologists

The recommendations and activities of the American Society of Clinical Pathologists (ASCP) pertaining to quality assurance in cytopathology are reviewed. To assure the early detection of cervical cancer, the ASCP recommends that all women who are, or have been, sexually active should have an annual Papanicolaou smear examination, the reasons for which are discussed. To assure the optimal quality in the evaluation of these smears, the ASCP recommends that the screening should be performed (1) in an accredited laboratory by certified cytotechnologists, (2) for whom realistic workloads have been established, (3) under the supervision of a pathologist adequately trained in cytology, (4) who will maintain an ongoing quality assurance program. In addition, (5) Papanicolaou smear evaluations should be available to all patients at a reasonable cost and (6) the financial incentives for the performance of low-quality screening should be eliminated. The society's quality assurance activities discussed include the Check Sample program, self-assessment examinations, meetings and publications; planned additions to this arena include a challenge exam and proficiency survey mechanisms.     

Noncontact dipole effects on channel permeation. III. Anomalous proton conductance effects in gramicidin

Proton transport on water wires, of interest for many problems in membrane biology, is analyzed in side-chain analogs of gramicidin A channels. In symmetrical 0.1 N HCl solutions, fluorination of channel Trp(11), Trp-(13), or Trp(15) side chains is found to inhibit proton transport, and replacement of one or more Trps with Phe enhances proton transport, the opposite of the effects on K(+) transport in lecithin bilayers. The current-voltage relations are superlinear, indicating that some membrane field-dependent process is rate limiting. The interfacial dipole effects are usually assumed to affect the rate of cation translocation across the channel. For proton conductance, however, water reorientation after proton translocation is anticipated to be rate limiting. We propose that the findings reported here are most readily interpreted as the result of dipole-dipole interactions between channel waters and polar side chains or lipid headgroups. In particular, if reorientation of the water column begins with the water nearest the channel exit, this hypothesis explains the negative impact of fluorination and the positive impact of headgroup dipole on proton conductance.     

Fine needle aspiration biopsy in the evaluation of lymphoreticular tumors of the thorax

The role of fine needle aspiration (FNA) biopsy in the evaluation of lymphoreticular disorders involving the lung and mediastinum was evaluated in a study of 16 cases from the authors' institutions. The cytologic material from these cases was reviewed, and the original cytologic interpretations were compared to the tissue diagnoses, with the overall accuracy of the cytologic interpretation evaluated. There were no false-positive diagnoses of malignancy in this series. A definite diagnosis of malignant lymphoma was most readily made in those cases in which the lymphoma was of the large-cell type. Small-cell and mixed large-cell and small-cell lymphoid proliferations were less able to be definitively interpreted, with pseudolymphoma presenting particular difficulty. The results support the conclusion that FNA biopsy can be useful in evaluating these lesions but also emphasize the fact that accurate diagnosis requires correlation of cytologic, clinical and laboratory data.     

Pemphigus vulgaris and microinvasive squamous-cell carcinoma of the uterine cervix

Although patients with disseminated pemphigus vulgaris may have involvement of the uterine cervix, such involvement is often detected only after vaginal discharge or bleeding. When a cervical smear is obtained, distinctive cytologic abnormalities may be observed; these may be attributed to the changes of pemphigus or to an associated reparative/inflammatory reaction. This study documents the first two cases of microinvasive squamous-cell carcinoma of the uterine cervix developing in association with uterine cervical pemphigus. The gross pathologic, cytologic and histologic features of these lesions are illustrated. The cytologic criteria that may be helpful in distinguishing between cells derived from microinvasive squamous-cell carcinoma and pemphigus of the uterine cervix are described.