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At least 577 records · Page 32Linked to original sources
PubMed1993

Temporal expression of tissue inhibitors of metalloproteinases in mouse reproductive tissues during gestation.

Tissue inhibitors of metalloproteinases (TIMPs) appear to play an important regulatory role in tissue remodelling and invasion by malignant cells. Since pregnancy involves morphological changes in existing maternal tissues, as well as a strictly controlled invasion by fetal trophoblasts, we have examined the temporal expression of TIMP-1, TIMP-2, and specific metalloproteinases in the mouse uterus, decidua, placenta, amnion, and ovaries throughout gestation by examining mRNA levels on northern and slot blots. Maximal levels of TIMP-1 mRNA were observed from day 6 to day 10 in the uterus, decidua, and placenta. In clear contrast to the early burst of TIMP-1 mRNA accumulation, the level of TIMP-2 mRNA increased steadily throughout gestation in the uterus, decidua, and amnion, while in the placenta it showed a sevenfold increase after day 14. In amnion, TIMP-1 was induced specifically on day 18. Interestingly, the normally high level of TIMP-1 mRNA seen in the ovaries of virgin mice was low during gestation, until day 18 and postpartum, when a sixfold increase over the levels in virgin ovary was observed. In contrast, ovarian TIMP-2 mRNA showed a marginal increase during gestation. The temporal pattern of 72 kDa gelatinase type A followed that of TIMP-2 in the decidua and ovary. Stromelysin-2 mRNA was detected at term only in ovary and decidua. Our data show that the temporal accumulation of TIMP-1 and TIMP-2 mRNA is precisely coordinated in each of the tissue compartments and is independently regulated during the in vivo remodeling of reproductive tissues in gestation.(ABSTRACT TRUNCATED AT 250 WORDS)

Amnion↗
PubMedDate not supplied

Biorheological features of some soft tissues under a surgical tissue expansion procedure.

The aim of this study was to investigate the effects of a surgical tissue expansion procedure on the biomechanical features of the expanded soft tissues. In this procedure a silicone balloon "expander" is surgically inserted into a tissue and inflated. The tissue mass increases under the stretch of the expander. The increased tissue can then be used as an autologous source for the surgical reconstruction of organs. In this article, dog saphenous neurovascular bundle was used. Expanded saphenous nerves, arteries and veins were harvested and their biomechanical features and ultrastructural, histological changes were studied. The stress relaxation features, the continuous spectrum of relaxation time, and the stress-strain relationship of expanded and control specimens were measured. Results show that within two or three weeks after placement of the expanders, the biomechanical properties of expanded saphenous nerves, arteries and veins began to deviate from those of their controls, and the differences between them were proportional to the volume of inflation; but when the expanding period was 15 weeks or longer, the properties of expanded specimens and their controls became close again. Histological study showed that the content of collagenous fibers in blood vessel walls decreased after expansion. The content of elastic fibers in blood vessel walls first increased, then returned to normal, and finally decreased. Ultrastructural studies showed that when elongated by 25-40%, the expanded nerves had well preserved axons and showed fewer smooth myelin sheaths only in the middle and distal part of the expansion.

Animals↗
PubMed1975

[Studies on the number of fat cells and connective tissue cells in white adipose tissue in chronic starvation and after refeeding. II. Investigations on obese and lean C 57 BL/6 J-mice (author's transl)].

UNLABELLED: Former investigations (Rakow et al., 1970, 1971a, b 1974) have demonstrated a constancy of the adipocyte number in white adipose tissue (parepididymal fat pads) of lean NMRI-albino-mice and aurothioglucose-obese NMRI-albino-mice during starvation and subsequent refeeding. In contrast the number of cells of connective tissue showed great variations under the experimental conditions mentioned above. The present paper describes which changes of the different cell populations within the adipose tissue could be demonstrated in lean and obese C57BL/6 J-mice. MATERIAL AND METHODS: The investigations were performed with obese and lean male C57BL/6 J-mice. The control animal groups were fed for six weeks 2.5 g (lean mice) and 2 g (obese mice), respectively, Altromin 1115R daily (starvation phase). After this time some of these animalwere killed (exp. groups H). The remaining animals now were fed Altromin 1115R and additional oat falkes ad libitum. Three (exp. groups HW3) and seven (exp. groups HW 7) days, respectively, after the beginning of the refeeding phase the animals were killed. After sacrifice the epididymal fat pads were weighed and treated with either (fat extraction). The dry mass was hydrolized with PCA (0.5 m, 90 degrees C, 40 min). In the supernatant the DNA (Burton, 1956), RNA (Ceriotti, 1955) and polysaccharide content (Seifter et al., 1950) were measured. The sediment was hydrolized with NaOH (0.5 n, 37 degrees C, 24 hrs). In this solution the protein content (Lowry et al., 1951) was determined. In addition fat cells were isolated according to Rodbell (1964). The fat cell diameters were determined microscopically and the average masses of the fat cells were estimated. From the wet weight of the fat pads and the average fat cell mass and number of fat cells were calculated. The remaining suspension of fat cells and cells of connective tissue were utilized for cell smears. These cell smears were stained with Schiff's reagent (Feulgen et al., 1924; Graumann, 1953). With an integrating microdensitometer (Deeley, 1955) the average relative DNA-content of single cell nuclei was measured and the ploidy patterns were estimated. The DNA-content was measured chemically according to Burton (1956). From the whole DNA-content of the fat pads and the DNA-content of the fat cell population the number of cells of the connective tissue was calculated...

Adipose Tissue↗
PubMed1995

Suitability of fetal tissues from spontaneous abortions and from ectopic pregnancies for transplantation. Human Fetal Tissue Working Group.

OBJECTIVE: To assess the potential availability and utility of fetal tissues obtained from spontaneous abortions and from ectopic pregnancies for human transplantation therapy. DESIGN: Tissue collection and analysis by personnel skilled in tissue banking. SETTING: Procurement programs in five tissue banks located in diverse geographical areas that are funded by the National Institutes of Health. PATIENTS: All women entering obstetric clinics during 1993 who consented to participate in the study. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Evaluation of the products of conception by standard developmental, histological, microbiological, and cytogenetic criteria. RESULTS: From 22,235 obstetric admissions, 1250 spontaneously aborted embryos and 247 products of ectopic pregnancies were obtained. Of these, seven embryos (0.5%) were potentially useful for human transplantation therapy. CONCLUSION: Fetal tissues from spontaneous abortions and from ectopic pregnancies are quite limited as feasible sources for human transplantation therapy.

Aborted Fetus↗