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N Romano FM Romano E Viviano F Vitale MR Villafrate AM Perna F Bonura R Guttadauro 《Canadian Metallurgical Quarterly》1996,34(6):1589-1591
We investigated by nested PCR the possible association of human herpesvirus 6 (HHV-6) and human papillomavirus (HPV) genomes in the cervixes of 109 women with normal and abnormal cytological smears. HPV DNA was detected in 8.33% of 24 women with normal cytologies and in 41.1% of 85 women with abnormal cytologies; the proportion of HPV DNA was directly related to the severity of the lesions. HHV-6 DNA was found in only one patient, who had a cytological pattern of koilocytosis. The HHV-6 genome was classified by restriction enzyme analysis as variant B. The study indicates that detection of the HHV-6 genome in the cervixes of women with a wide spectrum of gynecological complaints is a rare event and rules out the possible association between HHV-6 and HPV genomes in cervical cancer lesions. 相似文献
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BB Kragelund P H?jrup MS Jensen CK Schjerling E Juul J Knudsen FM Poulsen 《Canadian Metallurgical Quarterly》1996,256(1):187-200
Bovine acyl-coenzyme A binding protein is a four-helix bundle protein belonging to a group of homologous eukaryote proteins that binds medium and long-chain acyl-coenzyme A esters with a very high affinity. The three-dimensional structure of both the free and the ligated protein together with the folding kinetics have been described in detail for the bovine protein and with four new sequences reported here, a total of 16 closely related sequences ranging from yeasts and plants to human are known. The kinetics of folding and unfolding in different concentrations of guanidine hydrochloride together with equilibrium unfolding have been measured for bovine, rat and yeast acyl-coenzyme A binding protein. The bovine and rat sequences are closely related whereas the yeast is more distantly related to these. In addition to the three natural variants, kinetics of a bovine mutant protein, Tyr31 --> Asn, have been studied. Both the folding and unfolding rates in water of the yeast protein are 15 times faster than those of bovine. The folding rates in water of the two mammalian forms, rat and bovine, are similar, though still significantly different. A faster unfolding rate both for rat and the bovine mutant protein results from a lower stability of the native states of these. These hydrophobic regions, mini cores, have been identified in the three-dimensional structure of the bovine protein and found to be formed primarily by residues that have been conserved throughout the entire eukaryote evolution from yeasts to both plants and mammals as seen in the sample of 16 sequences. The conserved residues are found to stabilize helix-helix interactions and serve specific functional purposes for ligand binding. The fast one-step folding mechanism of ACBP has been shown to be a feature that seems to be maintained throughout evolution despite numerous differences in sequence and even dramatic differences in folding kinetics and protein stability. The protein study raises the question to what extent does the conserved hydrophobic residues provide a scaffold for an efficient one-step folding mechanism. 相似文献
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FM Ochberg 《Canadian Metallurgical Quarterly》1996,9(4):873-880
The three-dimensional (3-D) architecture of myosalpinx in the rat has been investigated by means of scanning electron microscopy after microdissection and removing interstitial connective tissue with 6N NaOH digestion. In the extramural portion of tube-uterine junction the myosalpinx shows circularly arranged fibers originating from the uterus, together with oblique fibers typical for the salpinx, which occur more frequently in the deeper layers. As fibers approach the mucous folds they assume a plexiform arrangement, which is maintained through all tubal segments. In the isthmus surface fibers form wide muscle rings around the elbow of loops, peculiar to the rat tubal morphology. Surface fibers in the ampulla and pre-ampulla have an even circular course. Our 3-D results reveal that the muscular architecture of rat tube is mainly organized in concentric, monolayered shells with a plexiform arrangement tightly fastened together. Functionally, this muscular arrangement seems to be capable of stirring rather than pushing the embryo and gametes. Finally, such a plexiform network might work as a mechanism of "tube locking" in proximity of isthmic loops as well as at the level of the ampullary-isthmic junction. 相似文献
6.
Changes in steady-state fluorescence anisotropy of 1 -(4-trimethylaminophenyl)-6-phenyl-1,3,5-hexatriene TMA-DPH) are applied to the detection of lamellar-hexagonal transitions in egg phosphatidylethanolamine. Even low (2 mole%) proportions of diacylglycerol decrease the hexagonal transition temperature considerably, as confirmed by differential scanning calorimetry. Diacylglycerol is also found to promote a lamellar to "isotropic" (Q(224) cubic) transition in mixtures of phosphatidylcholine: phosphatidylethanolamine:cholesterol. This nonreversible transition is also observed by (31)P nuclear magnetic resonance and detected as a large increase in TMA-DPH steady-state anisotropy. The same technique reveals as well that lysophosphatidylcholine counteracts the effect of diacylglycerol and stabilizes the lamellar phase in both transitions. Diacylglycerol and lysophosphatidylcholine are known to respectively promote and inhibit membrane fusion in a variety of systems. These data are interpreted in support of the hypothesis of a highly bent structural fusion intermediate ("stalk"). They also show the interest of lipid-phase studies in predicting and rationalizing membrane fusion mechanisms. 相似文献
7.
FM Scott AM Treston GL Shaw I Avis J Sorenson K Kelly EC Dempsey AB Cantor M Tockman JL Mulshine 《Canadian Metallurgical Quarterly》1996,14(2-3):239-251
Monitoring respiratory epithelial biology may reveal individuals with incipient lung cancer. The expression of neuroendocrine (NE) markers in pulmonary epithelium is thought to be central to lung development, repair of injury and may contribute to carcinogenesis. In this study, we evaluate several candidate NE markers to determine the feasibility of prospective analysis of clinical specimens. The potential NE markers include the enzyme L-DOPA decarboxylase (DDC), the neuropeptide gastrin releasing peptide (GRP), and peptidyl-glycine alpha-amidating monooxygenase (PAM), the bifunctional enzyme responsible for the final bioactivation step of many neuropeptides. A comparison of PAM activity and DDC levels in 30 lung cancer cell lines indicated that peptide amidating activity may be an indicator of NE status. Bronchoalveolar lavage (BAL) fluid from subjects at risk of developing second primary lung cancer and from volunteers was obtained. The activity of the first PAM enzyme, peptidylglycine alpha-hydroxylating monooxygenase (PHM), ranged from not detectable to 507 pmol/h/mg protein in 57 specimens. The second PAM enzyme, peptidylamidoglycolate lyase (PAL), ranged from not detectable to 414 pmol/h/mg protein in 56 specimens. Using cluster analysis by the average linkage method, a group of enzyme values with PHM greater than 230 pmol/h/mg protein was determined. Long-term follow-up of these patients for new second primary lung cancers may help to determine the potential predictive value of PAM detected in the BAL fluid. 相似文献
8.
M Monti V Pasta D Antonucci F Boccaccini FM Di Matteo S Lucci 《Canadian Metallurgical Quarterly》1996,17(10):543-546
The Authors report their experience in the treatment of ventral hernias using a Marlex mesh moulded in an original way with a technique partially derived from plastic surgery. The complete mobilization of the umbilicus through a circular incision allows to fit this prosthesis symmetrically below the rectus abdominis muscles for the entire extension of the hernia. 相似文献
9.
N Raffaelli FM Pisani T Lorenzi M Emanuelli A Amici S Ruggieri G Magni 《Canadian Metallurgical Quarterly》1997,179(24):7718-7723
The enzyme nicotinamide mononucleotide (NMN) adenylyltransferase (EC 2.7.7.1) catalyzes the synthesis of NAD+ and nicotinic acid adenine dinucleotide. It has been purified to homogeneity from cellular extracts of the thermophilic archaeon Sulfolobus solfataricus. Through a database search, a highly significant match was found between its N-terminal sequence and a hypothetical protein coded by the thermophilic archaeon Methanococcus jannaschii MJ0541 open reading frame (GenBank accession no. U67503). The MJ0541 gene was isolated, cloned into a T7-based vector, and expressed in Escherichia coli cells, yielding a high level of thermophilic NMN adenylyltransferase activity. The expressed protein was purified to homogeneity by a single-step chromatographic procedure. Both the subunit molecular mass and the N-terminal sequence of the pure recombinant protein were as expected from the deduced amino acid sequence of the MJ0541 open reading frame-encoded protein. Molecular and kinetic properties of the enzymes from both archaea are reported and compared with those already known for the mesophilic eukaryotic NMN adenylyltransferase. 相似文献
10.
DD Lund FM Faraci H Ooboshi BL Davidson DD Heistad 《Canadian Metallurgical Quarterly》1999,30(1):120-125
OBJECTIVE: Regional presynaptic dopaminergic function and its regulation by dopamine agonists in different stages of PD can be measured by L-[11C]dopa and PET. In the current investigation, we studied the effects of therapeutic apomorphine on L-[11C]dopa uptake in patients with early and advanced PD. BACKGROUND: With disease progression and chronic dopamine agonist treatment, motor response complications supervene in a majority of PD patients. It is assumed that both presynaptic and postsynaptic changes in the dopaminergic system act to modify dopaminergic efficacy. METHODS: Patients with early and advanced stages of PD were included in the study. All patients were investigated twice with PET and L-[11C]dopa drug free and during a subsequent standardized therapeutic apomorphine infusion. RESULTS: Subregional analysis of the striatum showed differences in the effects of apomorphine infusion on the L-[11C]dopa influx rate in the two patient categories. In patients with early and uncomplicated PD, apomorphine infusion decreased the L-[11C]dopa influx rate. This decrease was most pronounced in the dorsal part of the putamen. In advanced PD patients, apomorphine did not affect the striatal L-[11C]dopa influx rate. CONCLUSIONS: We suggest that in mild and stable PD an upregulated presynaptic inhibitory feedback regulation, particularly in the dorsal putamen, acts to maintain congruity within the dopaminergic system in response to antiparkinsonian medication. However, this inhibitory feedback regulation is diminished with the progression of nigrostriatal degeneration and chronic dopamine agonist treatment. 相似文献