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31.
Stable isotopic tracers of calcium have been used to characterize the absorption of dietary calcium and the subsequent distribution of this element through the body. For a group of 7 healthy children, ages 4-14, and 7 children with osteogenesis imperfecta (OI), types I, III and IV, ages 6-17, there were no detectable differences in the fractional absorption of dietary calcium, 0.29+/-0.11 and 0.28+/-0.16, respectively. The total exchangeable pool of calcium was found to be 161+/-52 mg/kg for the healthy children and 95+/-29 mg/kg for the 3 children with Type I OI, 250+/-75 mg/kg for the 3 children with Type III OI and 216 mg/kg for the child with Type IV OI. 相似文献
32.
Struchiner M Vieira AR Ricciardi RM 《Cadernos de saúde pública / Ministério da Saúde, Funda??o Oswaldo Cruz, Escola Nacional de Saúde Pública》1999,15(Z2):55-68
This study sought to analyze senior dental students' cognitive structure concerning the topic of "enamel", which is fundamentally important for understanding oral health, since it offers basic scientific concepts for clinical and preventive practices and is the main subject of several courses during dentistry training. The strategy used to analyze students' cognitive structures was Novak's Concept Maps, based on Ausubel's Meaningful Learning theory. Analysis of students' maps allowed for a study of students' cognitive structure and concepts concerning oral health. It also fostered a diagnosis of students' knowledge in several important aspects of scientific and professional training. The results highlighted the need for rethinking the teaching/learning process in dentistry training. 相似文献
33.
34.
Vieira NE Goans RE Weiss GH Hopkins E Marini JC Yergey AL 《Calcified tissue international》2000,67(2):97-100
Children with osteogenesis imperfecta (OI) type III and type IV were studied using a 42Ca stable isotope technique. Serum dilution kinetics of 42Ca were studied pre- and post-growth hormone (GH) treatment in 9 OI III (age range 5–9 years) and 8 OI IV patients (age range
5–12 years). Each subject was studied twice: at baseline and following GH therapy (range 1–1.5 years). Isotopic enrichments
of 42Ca were followed over 7 days using thermal ionization mass spectrometry. A binding site model, which describes reversible
and irreversible binding of calcium (Ca) ions to postulated short- and long-term binding sites in bone, was used to analyze
the kinetic data. In type III patients, GH treatment (1) increased the fraction of short-term binding sites, θ (0.777 ± 0.112
versus 0.877 ± 0.05, respectively; P= 0.034); (2) increased the apparent half-life of a Ca ion attached to the long-term binding site by 76% (P= 0.009); (3) although not statistically significant (P= 0.098), a trend toward an increased growth rate was observed with increasing change in θ (Δθ); (4) patients experienced
a 75% increase in growth rate during the first 6 months of treatment. In type IV patients, GH treatment increased the apparent
half-life of a Ca ion attached to the long-term binding site by 83% (P= 0.048), however, no trend toward an increased growth rate was observed with increasing Δθ in these patients. These significant
changes in Ca binding to bone may influence growth in type III patients.
Received: 10 September 1999 / Accepted: 29 February 2000 相似文献
35.
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37.
Isolation and characterization of propagable cell lines (HUNC) from the androgen-sensitive Dunning R3327H rat prostatic adenocarcinoma 总被引:1,自引:0,他引:1
Presnell SC; Borchert KM; Glover WJ; Gregory CW; Mohler JL; Smith GJ 《Carcinogenesis》1998,19(4):585-590
The Dunning H rat prostate tumor (R3327H) is a widely used experimental
model of human prostatic adenocarcinoma (CaP). The Dunning H tumor has been
characterized as androgen-sensitive, androgen-receptor (AR) positive,
prostate-specific antigen and prostatic acid phosphatase (PAP) positive. To
date, the tumor has been maintained by serial passage in vivo because of
the lack of an in vitro cell line that retains the characteristics of the
in vivo tumor. The objective of the present study was to establish a
propagable cell line from R3327H adenocarcinoma that maintained androgen
sensitivity and expression of AR, PSA and PAP. Tissue harvested from an in
vivo R3327H tumor was dissociated with collagenase and placed into
Richter's improved media (with supplements). A cytokeratin-positive
epithelial cell line (HUNC- E) and a vimentin-positive stromal cell line
(HUNC-S) were generated from the primary culture, subcultured continuously
for >300 days, and passaged >50 times. Survival of the HUNC-E cell
line in vitro depended on several media supplements, including
nicotinamide, insulin, transferrin, selenium and epidermal growth factor
(EGF). HUNC-E cells expressed AR and produced PSA and PAP throughout the
culture period, as confirmed by immunocytochemistry and Western blot
analyses. Addition of 14 nM testosterone (T) or dihydrotestosterone (DHT)
to HUNC-E cells, stimulated DNA synthesis as well as anchorage-independent
growth and PSA production, which demonstrated the androgen-sensitive nature
of the cells in vitro. When HUNC-E and HUNC-S cells were combined in a 3:1
ratio and introduced subcutaneously into syngeneic male hosts, tumors
formed in 2/3 animals with an average latency of 7 months. RT-PCR and
immunocytochemical characterization of the HUNC cell lines revealed that
the cells expressed several growth factors and their cognate receptors,
including HGF, TGF-alpha and the TGF-betas, indicating the establishment of
potential autocrine loops in the neoplastic cells. The HUNC-E and HUNC-S
CaP cell lines, which retain the characteristics of the epithelial and
stromal components of the in vivo R3327H tumor, will allow a more thorough
and informative molecular and biological analysis of prostatic
adenocarcinoma.
相似文献
38.
Previous work has shown that sustained increased and decreased cell
proliferation, induced by dietary zinc deficiency and caloric restriction
respectively, influence the course of N- nitrosomethylbenzylamine
(NMBA)-induced esophageal carcinogenesis in rats. The present study
considered whether the increased cell proliferation and esophageal tumor
incidence induced by zinc deficiency are reversed upon zinc replenishment.
Weanling rats were maintained initially on a deficient diet containing 4
p.p.m. zinc. After 5 weeks, carcinogen-treated animals were given six
intragastric doses of NMBA (2 mg/kg twice weekly). Controls were untreated.
After the second NMBA dose, the rats were divided into three dietary
groups. One group was continued on the deficient diet, while the other two
groups were switched to diets containing either 75 or 200 p.p.m. zinc, with
half of the members in each group fed ad libitum and half pair-fed with
deficient rats. NMBA-untreated controls were similarly replenished. At
various time points, esophageal cell proliferation was assessed in five
animals from each group by immunohistochemical detection of cells in S
phase, with in vivo 5-bromo-2'deoxyuridine labeling. At 11 weeks after the
first dose, esophageal tumor incidence was greatly reduced, from 100% in
the deficient group to 26 and 14% respectively in the replenished groups
fed ad libitum 75 and 200 p.p.m. zinc and to 14 and 11% respectively in the
replenished groups pair-fed 75 and 200 p.p.m. zinc. In addition, the number
of tumors per esophagus was reduced from 9.93 +/- 4.25 in deficient rats,
to a range of 0.11 +/- 0.31-0.30 +/- 0.54 in replenished animals. Following
zinc replenishment, esophageal cell proliferation, as measured by labeling
index (LI), the number of labeled cells and the total number of cells, was
markedly decreased in NMBA-untreated and -treated esophagi as compared with
those in corresponding deficient esophagi. Thus, the esophageal cell
proliferation induced by zinc deficiency is reversed by zinc replenishment
and replenished animals have a markedly lower incidence of esophageal
tumors.
相似文献
39.
Van Den Pol AN Vieira J Spencer DD Santarelli JG 《The Journal of comparative neurology》2000,427(4):559-580
Cytomegaloviruses (CMVs) are species-specific large double-stranded DNA viruses. Mouse and human CMVs have a similar morphology, similar gene sequence, and exert similar cellular effects, but the replication of the virus outside its primary host species is limited. This may confer upon CMV certain advantages for expression of foreign genes or cellular labels in brain cells of nonhost species. We examined the ability of recombinant mouse (m)CMV expressing green fluorescent protein (GFP) to serve as a vector for transgene expression in developing neurons and glia outside the normal host species. For comparative purposes, 11 species were examined. Mouse CMV reporter gene expression was particularly strong in the developing brain of its normal host species, mouse, where it replicated in cultures and brain slices, leading to cell death. All mammalian species tested (human, rat, gerbil, hamster, mouse) showed reporter gene expression after mCMV infection. High levels of mCMV infection were also found in chicken central nervous system cells in vitro, and a low level of mCMV expression was found after an initial delay in turtle neurons and glia. No mCMV reporter gene expression was found in frog cells or aplysia neurons or glia or in drosophila or fungal cells. Infection of nonmouse neurons by low concentrations of mCMV led to strong expression of GFP in dendrites and axons with normal morphology. Despite the lack of replication, high doses of mCMV induced morphologic changes in neurons and glia from hamster and rat brain slices, leading to cells rounding up, and to the formation of giant cells consisting of an aggregate of many cells fused together into a syncytium. In contrast, in human hippocampal slices, GFP-expressing cells infected with mCMV had a relatively normal appearance 12 days after inoculation. To determine whether a CMV from another species could serve as a vector for gene transfer, a recombinant human CMV-expressing GFP was used for transgene expression in rat brain cells in vitro. Cytomegaloviruses thus have potential as useful vectors for gene transfer and labeling central nervous system cells, with the actions of CMV being dependent on a number of factors. 相似文献
40.
Elisabeth Meloni Vieira Alcyone Artioli Machado Geraldo Duarte Regina Helena Brito de Souza Antonio Luis Rodrigues Junior 《Pan American journal of public health》2004,15(6):373-379
OBJECTIVES: To study HIV-positive women and women at risk of becoming infected with HIV who attended HIV prevention education group sessions at a university hospital in Brazil and to compare the use of the female condom and the male condom by these two groups of women. METHODS: The study subjects were 165 women participating in HIV prevention education group sessions at the Medical School Hospital of Ribeir?o Preto of the University of S?o Paulo, in the city of Ribeir?o Preto, S?o Paulo, Brazil. Women could be enrolled in the study from August 2000 to June 2001, and the follow-up observation time period was from August 2000 to July 2001. Male condoms and female condoms were freely distributed to all the participants at the end of each educational session and also at the end of each follow-up visit that the participants made. Each woman took part in an initial interview and was asked to return monthly. At each follow-up visit an additional short interview was carried out in order to investigate use of the male condom and of the female condom. Variables that were examined for the study included age, education, ethnic group, marital or relationship status, number of children, the women's use of male condoms and female condoms, commercial sex (whether the women had ever had sex in exchange for money, gifts, or favors), and previous knowledge of the female condom. RESULTS: The 165 women studied fell into the following three categories: 132 of them (80.0%) were HIV-positive, 26 of them (15.8%) had a sexually transmitted disease (STD) other than HIV and did not have an HIV-positive partner, and 7 of them (4.2%) had an HIV-positive partner but did not have HIV or any other STD. The women ranged in age from 15 to 64 years, with a mean of 30.3 years. Of the women in the study, 69.7% of them were married or were cohabitating, and 90.9% of them had a sexual partner. Just over two-thirds of the women had seven years of formal schooling or less. Out of 163 women, a total of 31 of them (19.0%) had never used the male condom with a partner, and 49 of the 163 (30.1%) had not used a male condom at the time of the last sexual intercourse. Out of the 165 women, 74 of them (44.8%) returned for at least one follow-up visit. Of these 74 women, 58 of them (78.3%) reported using the female condom between the initial interview and the first follow-up visit. The majority of the 74 women who returned for a visit liked using the female condom, and the women reported that their partners also generally accepted the female condom. In comparison to women at risk of HIV, HIV-positive women were more likely to have used the male condom with a partner before the initial interview. Women who continued returning over a longer follow-up period were more likely to have used the female condom at the time of the last sexual intercourse. No association was found between female condom use at the time of last sexual intercourse and the woman's HIV infection status. CONCLUSIONS: In comparison to the women at risk of HIV, the HIV-positive women in our study were more likely to use male condoms with their partners, to return for follow-up visits, and to have a longer follow-up period. The acceptance of the female condom among the HIV-positive women in this study, as reported at their first follow-up visit, appears to be similar to the acceptance of the female condom among women in general in Brazil. 相似文献