Distribution of TT virus genomic groups 1-5 in Brazilian blood donors, HBV carriers, and HIV-1-infected patients

Human isolates of the highly prevalent TT virus (TTV) have been classified into five major genomic groups (1-5). The geographical distribution of the groups throughout the world is not well known. Five different PCR assays were developed in an attempt to amplify specifically TTV DNAs of each genomic group. Serum samples collected from 72 Brazilian adults (24 voluntary blood donors, 24 hepatitis B virus (HBV) carriers, and 24 human immunodeficiency virus type 1 (HIV-1)-infected patients) were tested. TTV DNA from at least one genomic group was detected in 11 (46%) blood donors, 13 (54%) HBV carriers, and 24 (100%) HIV-1 patients. All five genomic groups were detected in the three populations, with the exception of group 2 in blood donors. Some samples, negative with all five specific assays, were positive with the commonly used untranslated region (UTR) PCR system. On the other hand, TTV DNA was detected in some samples by using specific assays but not with the UTR PCR. Mixed infections with 2-5 TTV isolates from different groups were detected in 21% blood donors, 29% HBV carriers, and 71% HIV-1 patients. Fifteen PCR products (three obtained with each assay) were sequenced. Most sequences showed high (>86%) homology with those of TTV isolates belonging to their presumed groups. However, three sequences had low homology with all TTV sequences available from the DNA databanks. In conclusion, TTV isolates belonging to all five known genomic groups circulate in Brazil, and the results suggest the existence of new and as yet uncharacterised major genomic groups.     

Aspiration cytology of ameloblastic fibroma: a diagnostic challenge

Ameloblastic fibroma of the jaw is a rare, benign mixed odontogenic tumor, having little tendency for local invasion and a low recurrence rate. Cytologic distinction from ameloblastoma, ameloblastic fibrosarcoma, and intraosseous adenoid cystic carcinoma is necessary, in view of the different biologic behavior. A painful, slow-growing swelling of the jaw in a 5-yr-old child clinicoradiologically considered as a benign cystic lesion was aspirated. Sheets of small monomorphic epithelial cells with peripheral palisading by columnar cells were seen on cytology smears. The striking feature was central hyaline globules in some tubules. A cytologic possibility of adenomatoid odontogenic tumor was suggested. Histopathology, however, confirmed it to be an ameloblastic fibroma.     

Cytokine induction of neopterin production.

The pteridine neopterin is a marker of immunological activation and has been shown to be a useful marker of graft-versus-host disease (GVHD) in bone marrow transplant patients. High levels of both neopterin and interferon-gamma (IFN-gamma) were produced in vitro during mixed lymphocyte responses, which may be considered to be a model of the primary events leading to GVHD. Neopterin was shown to be produced by monocytes in response to stimulation with IFN-gamma, but not other cytokines. However, the interleukins IL-1 alpha, IL-1 beta, IL-2, and tumour necrosis factor (TNF) alpha and beta, but not IL-6, stimulated neopterin production by unfractionated peripheral blood mononuclear cells (PBMC), and culture supernatants from PBMC stimulated with IL-1 alpha, IL-1 beta, IL-2 and IL-6, but not TNF-alpha or TNF-beta induced neopterin production following transfer to fresh monocyte cultures. It therefore appears that cytokines may generate neopterin by induction of IFN-gamma, by synergy with low levels of induced IFN-gamma, or by non-IFN-gamma-dependent mechanisms.     

Mixed microbial aetiology of community-acquired pneumonia in children

Seven paediatric studies on community-acquired pneumonia with serological methods for both viruses and bacteria have been published, allowing the evaluation of concomitant multiple etiological findings. In these studies, dual viral infection has been present in 0-14%, dual bacterial infection likewise in 0-14%, and mixed viral-bacterial infection in 3-30% of the pneumonia cases. The results confirm former clinical observations that respiratory viruses often pave the way for airway-colonising bacteria. The measured frequency of multiple infections has been dependent on the available test panel, mainly on the tests used for pneumococcal aetiology. Mixed viral-bacterial infections have been especially common in young children under 2 years of age, reflecting the high frequency of respiratory syncytial virus infections and their tendency to induce bacterial co-infections. No microbe-specific viral-bacterial associations have been demonstrated. The clinical implications of mixed viral-bacterial infections, compared with viral infections alone or bacterial infections alone, have so far remained unresolved. Current guidelines recommend antibiotic therapy for all community-acquired pneumonia cases in children.     

冲击波致伤作用实验研究进展

原发冲击伤是爆炸产生的冲击波直接作用于生物体而引起的。各种生物激波管和其它冲击波发生装置的研制大大促进了冲击波致伤作用的实验研究的开展。通过将多种动物、离体器官以及培养的细胞暴露于冲击波,获得了大量的原发冲击伤实验研究结果。作者在简述冲击波的基本物理学特征的基础上,着重概括了生物激波管研制和原发冲击伤实验研究方法及其主要进展。     

Mixed neuronal–glial tumor of the digestive tract: Distinctive entity from gastrointestinal stromal tumor?

A 53-year-old-woman presenting with pelvic discomfort was found to have a 9.5 cm tumor located in the wall of the ileon. Light microscopy showed that the tumor was made of fascicles of plump spindle cells and bizarre epithelioid cells. A cuff of lymphoid cells was also present at the tumor margin. The tumor cells strongly expressed tau protein, neuron-specific enolase, protein green product 9.5 and glial fibrillary acid protein (GFAP), but did not show positive immunostaining for S-100 protein, CD34 or CD117. The tumor showed unequivocal ultrastructural evidence of neural differentiation. Skeinoid fibers were scattered throughout the tumor. This is the first mixed neuronal-glial tumor of the digestive tract to be described in the literature. Such histological and immunohistochemical features could be misinterpreted as features of digestive schwannoma. We suggest that this tumor is distinct from gastrointestinal stromal tumors in lacking CD34 and CD117 expression.     

Detection of non-HLA-DR determinants by alloreactive lymphocyte clones

Using the soft-agar colony assay, we have generated three MT3-associated clones: HJ1, HJ13, and HJ39, from an MLR combination of two unrelated individuals. Another clone, HJ37, appeared to recognize a novel HLA-D determinant. PLT inhibition studies with monoclonal anti-Ia-like antibodies (Mab) were conducted on clones HJ1, HJ39, and HJ37. Five different anti-DR Mab had no significant inhibitory effect on these clones. On the other hand, two Mab SG171 and Q5/13 which appear to react with DR and MT3 (I-A like) molecules strongly inhibited the two MT3-specific PLT clones. While SG171 and Q5/13 had little effect on HJ37, it was observed that a polymorphic Mab 17.15 had a strong inhibitory effect. These results, in concordance with biochemical data on Ia molecules precipitated by these Mab, suggest that these alloreactive clones may recognize non-DR PLT determinants. They also provide further indirect support that MT3 molecules represent the human homologue of murine I-A molecules.     

Specific and non-specific components in the triggering of proliferative and cytotoxic responses of T lymphocytes with different cell density

We hve analyzed the functional behavior of lymphocyte subsets separated on the basis of cell density. Low and high density subpopulations were cultured in FCS, alone or with allogeneic irradiated PBL, and then examined for proliferation and cytotoxic activity against autologous (responder) and allogeneic (stimulator) PHA-induced blasts, K562 and Daudi. In the high density subset proliferation and generation of anti-K562 and anti-Daudi effects were induced by FCS and to higher extent by allospecific stimulation. Exposure to alloantigens induced allospecific cytotoxicity. Autologous PHA blasts were not affected. The results with the low density subset differed. Independently of the type of stimulus imposed, the low density fraction showed little if any proliferation, but its cytotoxic activity was stronger against all targets tested. In some of the experiments, anti-alloblast cytotoxicity was generated in the control cultures. Thus, polyclonal activation induced by FCS triggered in this fraction allospecific cytotoxicity. In this subset, the effect against allogeneic PHA blasts comprised a specific and a non-specific component because autologous PHA blasts were also lysed. Limiting dilution analysis involving allostimulation showed higher frequency of cytotoxic precursors in the low density subset. Split minicultures were tested for lysis of auto- and allogeneic blasts. Alloreactive cultures that did not lyse the autologous target were more frequent in the cultures initiated with the high density cells. There was no conclusive evidence for the existence of autoreactive cultures that did not lyse the allogeneic blasts.     

冲击伤肺肋面的平行出血条纹

本文采用部分肋骨切除术,切除15只家兔双侧5、6、7、8肋中任一肋距脊柱约2cm处一段长约1cm的肋骨。一周后对受冲击波致伤的肺肋面的出血情况进行解剖观察,发现肺肋面的出血条纹呈“工”字形,从而为冲击伤肺肋面的平行出血条纹是肋间压痕这一观点找到了直接的实验证据。     

利用脉搏波特征参数连续测量血压的方法研究

通过研究血压与脉搏波特征参数的关系，提出了一个选择多个与血压相关的脉搏波特征参数,通过回归分析建立适合不同人的特征方程，进行血压的连续测量的新方法，为了验证测量结果的准确性；研制了张力计。实验结果表明：该方法具有较高的测量精度，可以应用于临床危重病人的血压监护和一般医学研究中，经过进一步地改进和完善后可应用于载人航天和日常动态环境。