In situ analysis of adhesion molecule expression in kidneys infected with murine malaria

Two toluene-sensitive mutants were generated from Pseudomonas putida IH-2000, the first known toluene-tolerant isolate, by Tn5 transposon mutagenesis. These mutants were unable to grow in the presence of toluene (log P(ow) 2.8) but they could grow in medium overlaid with organic solvents having a log P(ow) value higher than that of toluene such as p-xylene (log P(ow) 3.1), cyclohexane (log P(ow) 3.4) and n-hexane (log P(ow) 3.9). The Tn5 transposable element knocked out a cyoB-like gene in one mutant and a cyoC-like gene in the other mutant. Seven open reading frames were found in a 5.5-kb region containing the cyoB- and cyoC-like genes of strain IH-2000. ORFs 3.7 showed significant identity to the cyoABCDE gene products of Escherichia coli, but ORFs 1 and 2 showed no significant homology to any protein reported so far. The growth patterns of the Tn5 mutants with the inactivated cyo-like gene were similar to that of the wild-type strain in the absence of organic solvents, although the doubling times were slightly longer than that of the wild-type strain. Our findings indicate that cyo is an important gene for toluene tolerance, although its role is still unclear.     

Persistence of humoral response against sporozoite and blood-stage malaria antigens 7 years after a brief exposure to Plasmodium vivax

The persistence of malarial antibodies was evaluated in subjects living in a rural community (in Minas Gerais State, Brazil) briefly exposed to a Plasmodium vivax malaria outbreak outside of the area in which malaria was endemic. Transmission was interrupted by treatment of all patients and their relatives and/or neighbors, although the latter had neither symptoms nor blood parasites. Antibodies to P. vivax antigens (recombinant proteins from sporozoites [rPvCS] and from blood stages [rPv200]) were measured in parallel by ELISA with sera collected at two time points after transmission. Anti-rPvCS IgG antibodies were positive in approximately 40% and 20% of the subjects 8 months and 7 years after exposure, respectively. Anti-rPv200 IgG was first detected in 61% of the subjects who had had malarial symptoms and remained positive in 47% after 7 years. Among the prophylactically treated group, anti-rPv200 IgG was detected in only 28% after 8 months. The levels of both antibodies decreased with time in all positive subjects.     

Role of axillary lymph node dissection after tumor downstaging with induction chemotherapy for locally advanced breast cancer

BACKGROUND: Induction chemotherapy has become the standard of care for patients with locally advanced breast cancer (LABC) and currently is being evaluated in prospective clinical trials in patients with earlier-stage disease. To better gauge the role of axillary lymph node dissection in patients with LABC this study was performed to assess initial axillary status on physical and ultrasound examination, axillary tumor downstaging following induction chemotherapy, and the accuracy of physical examination compared with axillary sonography in predicting which patients will have axillary lymph node metastases found on pathologic examination. METHODS: Between 1992 and 1996, 147 consecutive patients with LABC were registered in a prospective trial of induction chemotherapy using 5-fluorouracil, doxorubicin, and cyclophosphamide. Physical and ultrasound examinations of the axilla were performed at diagnosis and after induction chemotherapy. Segmental resection with axillary lymph node dissection or modified radical mastectomy was performed, followed by postoperative chemotherapy and irradiation of the breast or chest wall and regional lymphatics. RESULTS: Following induction chemotherapy, 43 (32%) of the 133 patients with clinically positive lymph nodes on initial examination had axillary tumor downstaging as assessed by physical and ultrasound examination. The sensitivity of axillary sonography in identifying axillary metastases was significantly higher than that of physical examination (62% vs. 45%, P=.012). The specificity of physical examination (84%) was higher than that of sonography (70%), but the difference did not reach statistical significance. Among the 55 patients in whom the findings of both physical and ultrasound examination of the axilla were negative following induction chemotherapy, 29 patients (53%) were found to have axillary lymph node metastases on pathologic examination of the axillary contents. However, 28 (97%) of these patients had either 1 to 3 positive lymph nodes or only micrometastases 2 to 5 mm in diameter. CONCLUSIONS: Preoperative clinical assessment of the axilla by physical examination combined with ultrasound examination is not completely accurate in predicting metastases in patients with LABC following tumor downstaging. However, patients with negative findings on both physical and ultrasound examinations of the axilla may be potential candidates for omission of axillary dissection if the axilla will be irradiated because minimal axillary disease remains. Patients who have positive findings on preoperative physical or ultrasound examinations should receive axillary dissection to ensure local control. A prospective randomized trial of axillary dissection versus axillary radiotherapy in patients with a clinically negative axilla following induction chemotherapy is currently underway.     

Machine tool chatter monitoring by coherence analysis

A new method based on coherence analysis in the frequency domain for predicting chatter is presented. From the evidence of the experiments conducted, the ability of this method to detect different types of chatter does not seem to be affected by the cutting conditions. The theory of the method is presented, which is then validated by experiments also described.     

二维平面有限单元法在坝体渗流稳定评价中的应用——以赤泥堆场4~#坝北坝段渗流稳定分析评价为例

中铝贵州分公司赤泥堆场4#坝为库中坝,坝为赤泥堆砌而成,其北坝段位于二叠系茅口组、龙潭组交接地段附近,随着该坝的不断加高使用,对该坝北段的渗流稳定进行了分析,其间用到的一些计算方法值得借鉴。     

Effect of 2'-OH acetylation on the bioactivity and conformation of 7-O-[N-(4'-fluoresceincarbonyl)-L-alanyl]taxol. A NMR-fluorescence microscopy study

The relationship between conformation, 2'-OH acetylation, and bioactivity of two fluorescent taxoids has been investigated by a combination of NMR and fluorescence microscopy techniques. These taxoids present the structure of taxol with the 7-OH group esterified with the N-(4'-fluoresceincarbonyl)-L-alanine group and with the 2'-OH group free (taxoid 2) or acetylated (taxoid 3). The larger water solubility of 2 and 3 compared with taxol allowed a detailed NMR study in DMSO-d6/D2O (3/7), showing that both taxoids adopt a similar collapsed conformation in which the hydrophobic groups 2-O-benzoyl, 3'-phenyl and 4-O-acetyl are in close proximity, with the fluorescein group displaying unrestricted motion. On the other hand, while taxoid 2 retains essentially the ability of taxol to induce in vitro microtubule assembly and to bind to cell microtubules, the 2'-acetylated derivative 3 does not show immediate activity. However, when taxoid 3 is left in the cell culture, the slow hydrolysis of the 2'-acetate group in the medium liberates the cytotoxic, microtubule-specific taxoid 2. The intense emission of this active derivative (2) allows the accurate recording of the drug-cell interaction from the very initial steps using fluorescence microscopy. These experiments show conclusively, for the first time in cell cultures, that a free 2'-OH group in taxol is essential for the recognition of the drug by the binding site of cellular microtubules.     

Environmental fibrous zeolite (erionite) exposure and malignant tumors other than mesothelioma

We studied the mortality in three villages in the Cappadocian region of Central Anatolia, Karain, Tuzk?y, and Sarihidir, which were exposed to fibrous zeolite (erionite), a known carcinogen more potent than the amphibole asbestos. Between 1970 and 1994, there were 305 deaths in Karain, and 177 (58%) were cancer related, including 150 (49.2%) malignant pleural mesothelioma, seven (2.3%) malignant peritoneal mesothelioma, and six (1%) gastroesophageal carcinoma. Four deaths (1.3%) from lung cancer included two nonsmoking females. There were three cases (1%) of leukemia and six of other malignancies (1.9%). Between 1980 and 1994, there were 519 deaths in Tuzk?y (T) and Sarihidir (S) (T = 432, S = 87). Of these, 257 were cancer related, and included 120 cases of malignant pleural mesothelioma and 64 cases of malignant peritoneal mesothelioma. Intraabdominal carcinoma was noted in 29 patients and 14 patients had lung cancer (four of whom were nonsmoking women). There were five cases of gastroesophageal cancer, five deaths due to leukemia, and 16 cases of various malignancies. These mortality figures support the hypothesis that erionite fibers cause cancer other than mesothelioma and lung cancer. Mineralogic analyses of the tissues should be performed to demonstrate this relationship.     

Ecto-ATPases and receptors for ATP

Guerilla warfare procedures injuries that are intended to have a psychologic as well as a physical effect on the victims. Intentional violence in the form of punishment beatings or shootings inflicted on one person are used to control the behavior of members of a like group. Bombings and social chaos are used to disrupt life in the community and produce random types of violent injuries. In Belfast health care providers care for trauma victims from both sides of the warfare and are subject to becoming victims of violence themselves.     

Molecular genetic analysis of patients carrying steroid 21-hydroxylase deficiency in the Mexican population: identification of possible new mutations and high prevalence of apparent germ-line mutations

There is growing evidence that the receptor-binding characteristics of influenza viruses are affected by the host-dependent glycosylation of viral hemagglutinin (HA). To better understand these effects, we propagated two variants of the human influenza virus USSR/90/77 (which differed by the mutation Asn131 reversible Asp131 in the glycosylation sequon of their HA) in either embryonated chicken eggs or MDCK cell. Those variants were then compared for their ability to bind soluble receptor analogs and to attach to receptors represented on a solid phase. The carbohydrate chain at position 131 of the HA (CHO 131) interfered with virus binding to soluble Sia2-6Gal-containing macromolecular receptors, but had little or no effect on its binding to Sia2-3Gal-containing macromolecules. This specificity could be explained by the different orientation of the asialic parts of the 2-3-linked sialosides versus 2-6-linked sialosides with respect to the receptor-binding site (Eisen et al., 1997, Virology 232, 19-31). In the case of virus attachment to solid-phase immobilized receptors, MDCK-grown viruses bound substantially more weakly than their egg-grown counterparts to receptors of avian origin, whereas binding to mammalian cell membranes was only marginally affected by differences in host-specific glycosylation of the virus. Our data indicated that the effects of the carbohydrate side chain of HA on virus receptor-binding activity are dependent on both the cells in which the virus was grown and the nature of the cellular receptors or intercellular inhibitors to which the virus binds.