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51.
A case of extraskeletal osteosarcoma was observed in the thigh of a 33-year-old male patient. Ultrastructurally the tumor was characterized by the presence of a particular dense type of cell, the nucleus of which showed a characteristic combination of features: large amounts of condensed mar-ginated chromatin, prominent perichromatin granules, vermicellar bodies, and undulating microtubules. The tumor also contained intermediate-type cells with a more typical osteoblastic appearance, and more blastic cells. All three cell types contained varying amounts of dilated rough endoplasmic reticulum with prominent inclusions of crystalline material showing a hexagonal or banded pattern, indicating that the cells represent different stages of maturation rather than genuinely different types of cells. Dense cells showing the same characteristic combination of nuclear features have been described once before in a case of parosteal osteosarcoma. Our results indicate that these cells are a particular form of osteogenic cell. The presence of undulating microtubules and vermicellar bodies suggest a possible association with the presence of virus and/or increased levels of interferon.  相似文献   
52.
The objective of this study was to assess the association betweenalcohol drinking before and during pregnancy and the risk ofspontaneous abortion using data from a case-control study conductedin Milan, Italy. A total of 462 women (median age 30 years)were admitted for spontaneous abortion (within the 12th weekof gestation) to a network of obstetrics departments in thegreater Milan area. Of these, 148 (32%) were between the fourthand the eighth week of gestation and 314 (68%) between the ninthand the 12th week. A control group was made up of 814 women(median age 29 years) who gave birth at term (>37 weeks gestation)to healthy infants (Apgar 5th minute 8, weight 3000 g) on randomlyselected days at the same hospitals where cases had been identified.A total of 212 cases (46%) and 355 controls (47%) reported alcoholdrinking before conception. Considering non-drinkers as thereference category, the relative risks (RR) of spontaneous abortionwere 1.2 (95% confidence interval (CI), 0.9–1.6] and 0.8(95% CI, 0.6–1.1), respectively, in drinkers of one toseven and more than seven drinks per week before conception.No association emerged between the duration of alcohol drinkingand the risk of spontaneous abortion. A total of 166 cases (35.9%)and 263 (32.3%) controls reported any alcohol drinking duringthe first trimester of pregnancy. The corresponding relativerisk was 1.1 (95% CI, 0.9–1.4) and no relationship emergedbetween the number of drinks per week and the risk of abortion.Likewise, maternal wine and beer drinking in the first trimesterof pregnancy was not associated with the risk of spontaneousabortion. Evidence available from this and previous studies,although partially controversial, indicates that moderate (oneor two drinks per day) alcohol consumption does not increasemarkedly the risk of miscarriage.  相似文献   
53.
Telomerase is the enzyme responsible for synthesizing telomeric repeats at the ends of chromosomes to maintain telomere length. Recent studies have suggested that telomere shortening may serve as a surrogate marker of the progression of malignant disorders and seems to be accelerated in allogeneic bone marrow transplant recipients. In this study, the results of the telomere length of nine cord blood mononuclear cell samples are presented. Telomere length was measured by the flow-FISH method, using a peptide nucleic acid probe. The proportion of cord blood cell subsets (CD19/CD34/CD3) was also evaluated. The telomere length of the internal control 1301 cell line was estimated to be 100%. The mean telomere length of cord blood cells was 18.5 +/- 3.9%, compared with the internal control. The progenitor CD34+ cells were detected as 2.6 +/- 0.7% in the lymphoid gate measured. Linear correlation analysis did not find any connection between the cell subsets (CD3+, CD34+, CD19+) and the telomere length. The findings confirm that the telomere flow-FISH method is sufficient for estimation of the telomere length. Assessment of the current procedures of collection, manipulation, and ex vivo expansion of cord blood cells in terms of their effect on telomere shortening might be important.  相似文献   
54.
Human oocyte development was evaluated after a reduced timeexposure to spermatozoa in vitro. A total of 119 patients wereassigned to two study groups in a randomized prospective studyin which each patient‘s oocytes were exposed to spermatozoafor either 1 h (group 1 – 58 patients) or the standard16 h incubation period (group 2 – 61 patients). The fertilizationrate obtained in group 1 was higher than in group 2 (285/393,73%, and 272/410, 66% respectively), suggesting that the spermatozoa-oocyteinteraction occurs within 1 h. This was confirmed in a studyin vitro using fluorescently labelled spermatozoa and normaloocyte-cumulus complexes. Spermatozoa enter the cumulus complexwithin 15 min, traverse the cumulus layer within 3 h, and firstappear in the oocyte cortex at 4 h post-insemination. The incidenceof polyspermy was higher in oocytes exposed to spermatozoa for16 h (3%) than for 1 h (1%). There was no difference in thecleavage rate or morphological characteristics of embryos fromboth study groups. However, when evaluating the timing of embryodevelopment, group 1 generated a significantly higher percentageof four to five cell embryos when compared to group 2 (55 versus39%; P < 0.001), documented at 40 h post-insemination. Theimplantation and pregnancy rates for group 1 were 11 and 28%,while the corresponding rates for group 2 were 8 and 15%. Thissuggests that a reduced exposure of oocyte to spermatozoa favoursembryo viability, possibly due to a decrease in potential damagefrom sperm metabolic waste products.  相似文献   
55.
The present study was performed to investigate the effect of treatment with furosemide on the pressor response induced by intracerebroventricular (i.c.v.) injections of cholinergic (carbachol) and adrenergic (norepinephrine) agonists, angiotensin II (ANGII) and hypertonic saline (HS, 2 M NaCl). The changes induced by furosemide treatment on the pressor response to intravenous (i.v.) norepinephrine, ANGII and arginine vasopressin (AVP) were also studied. Rats with a stainless-steel cannula implanted into the lateral ventricle (LV) were used. Two injections of furosemide (30 mg/kg b.wt. each) were performed 12 and 1 h before the experiments. Treatment with furosemide reduced the pressor response induced by carbachol, norepinephrine and ANGII i.c.v., but no change was observed in the pressor response to i.c.v. 2 M NaCl. The pressor response to i.v. ANGII and norepinephrine, but not AVP, was also reduced after treatment with furosemide. These results show that the treatment with furosemide impairs the pressor responses induced by central or peripheral administration of adrenergic agonist or ANGII, as well as those induced by central cholinergic activation. The results suggest that the treatment with furosemide impairs central and peripheral pressor responses mediated by sympathetic activation and ANGII, but not those produced by AVP.  相似文献   
56.
Thirty sera reacting by IFL technique in titres greater than or equal to 100 with smooth muscle fibres of rat stomach, rat renal glomeruli, and with the membrane region of thyroid cells were randomly chosen among sera sent in for routine testing of tissue antibodies. All sera but one were found to be derived from patients with chronic active hepatitis. The smooth muscle and other relevant cell staining were abolished after absorption of sera with actin, prepared from rabbit skeletal muscle and found to be homogeneous by SDS gel-electrophoresis and by electron microscopy. The actin anti-bodies were purified by precipitation of sera with F-actin and elution of the precipitates at acid pH. The purified antibodies stained all tissues in the same way as the original sera. In double immunodiffusion tests all thirty sera gave precipitation with actin. Thus, it was concluded that these broad-reacting SMA are directed against actin. The finding of high-titred SMA is of diagnostic value and supports the clinical diagnosis of active chronic hepatitis. In addition, anti-actin antibodies eluted from human sera are a suitable tool for studying actin-containing cellular structures.  相似文献   
57.
The GafChromic film (GCF) MD-55-2, a radiochromic material, was examined for its optical properties through total reflectance and transmittance measurements in visible spectrum (400-700 nm). By using a multilayer model of the film and Kubelka-Munk's (KM) theory, absorption and scattering coefficients of the film sensitive layer (K and S, respectively) were obtained from measurements of irradiated and nonirradiated slides. This has allowed calculation of the absorbance A(KM) of the sensitive layer of the GCF. The model easily splits scattering from absorption. Unlike absorption, scattering is essentially insensitive to irradiation dose and decreases slowly as the wavelength increases. The scattering effect is predominant over absorption in the 400-500 nm range, while beyond 600 nm absorption prevails. The A(KM) absorbance of the sensitive layer was calculated using the K coefficient and compared with the optical densities (OD) measured considering only ballistic photons (as in a standard spectrophotometer) as well as the optical densities measured collecting all the transmitted photons (as in many densitometers). The values of A(KM) found were always lower than OD measured by the other methods and they had the best linearity on the whole visible range. These data support the hypothesis that the sensitive layer reacts to irradiation more linearly than that shown by measurements using standard commercial devices. However, in the 600-680 nm range, correction is not very important because absorption is predominant over scattering. When GCF is used for imaging, scattering produces a loss of spatial information. Consequently, it is necessary to collect only ballistic photons and to correct absorbance by K and S coefficients.  相似文献   
58.
A new approach for the M-typing of Streptococcus pyogenes is reported. Oligonucleotide primers were used in a PCR to amplify the N-terminal region of the emm gene. The presence of the PCR amplification product is associated with the corresponding M serotype. This technique offers potential advantages over other molecular typing methods.  相似文献   
59.
Summary A study was performed to investigate the changes that occur in the median frequency of the myoelectric signal during local ischemia or reduction of intramuscular temperature produced by surface cooling. Data was obtained from experiments which involved the first dorsal interosseous muscle of 10 female and 16 male subjects. These subjects were asked to perform isometric constant-force abduction contractions of the index finger at 20% and 80% of maximal voluntary contraction level. The initial median frequency (IMF) of the myoelectric signal during the first 0.5 s of contraction was calculated. Results showed a significant reduction of the IMF in contractions performed under ischemic conditions; upon release, the IMF recovered quickly. At 80% maximal voluntary level of contraction, a greater decrease of the IMF was recorded. Similar results were demonstrated during reduction of intramuscular temperature with gradual recovery of the IMF after cooling. These results demonstrate that the median frequency of the myoelectric signal displays behavior similar to that reported for conduction velocity and this is consistent with the notion that accumulation of metabolic byproducts in muscle tissue causes a decrease in the conduction velocity of the muscle fibers.Dr. R. Merletti was on a leave of absence from the Institute of Electrical Engineering, Politecnico di Torino, Italy  相似文献   
60.
Immunotherapy using adoptive cell transfer is a promising approach that can result in the regression of bulky, invasive cancer in some patients. However, currently available therapies remain less successful than desired. To study the mechanisms of action and possible improvements in cell-transfer therapies, we use a murine model system with analogous components to the treatment of patients. T cell receptor transgenic CD8+ T cells (pmel-1) specifically recognizing the melanocyte differentiation antigen gp100 are adoptively transferred into lympho-depleted mice bearing large, established, 14-day subcutaneous B16 melanoma (0.5-1 cm in diameter) on the day of treatment. Adoptive cell transfer in combination with interleukin interleukin-2 or interleukin-15 cytokine administration and vaccination using an altered form of the target antigen, gp100, can result in the complete and durable regression of large tumor burdens. Complete responders frequently develop autoimmunity with vitiligo at the former tumor site that often spreads to involve the whole coat. These findings have important implications for the design of immunotherapy trials in humans.  相似文献   
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