Biomedical subjects

C A Koks

Publications and source records attributed to C A Koks.

9 recordsLinked to original sources

PubMed2000

Matrix metalloproteinases and their tissue inhibitors in antegradely shed menstruum and peritoneal fluid.

OBJECTIVE: To investigate the expression of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in antegradely shed menstruum and peritoneal fluid. DESIGN: A cell biological and immunohistochemical study. SETTING: Tertiary care university medical center. INTERVENTION(S): Immunohistochemistry was performed on cryostat sections and cultures of menstrual endometrium. Zymography was used to characterize MMP activity in peritoneal fluid, in menstrual serum, and in conditioned medium. Western blot analysis was used to further identify the MMPs in these fluids. MAIN OUTCOME MEASURE(S): Staining of MMPs and TIMPs in cryostat sections and cultures and MMP expression and activity in peritoneal fluid and menstrual blood serum. RESULT(S): Strong staining for MMP-1 and MMP-3 was observed in stroma and for MMP-7 in epithelium. Matrix metalloproteinase-2 and MMP-9 were weakly expressed in stroma. Both TIMP-1 and TIMP-2 were expressed in menstrual endometrium. Menstrual serum showed a pattern of MMP activity on zymography different from peritoneal fluid. Western blot analysis showed the presence of MMP-7 and MMP-9 in menstrual serum. CONCLUSION(S): Antegradely shed menstrual endometrium expresses several MMPs and TIMPs, even after culturing for 24 hours. MMP activity in menstrual serum is different from and more intense than MMP activity in peritoneal fluid. These enzymes may be involved in the early invasion of menstrual endometrium into the extracellular matrix of the peritoneum.

Ascitic Fluid↗

PubMed2000

Adhesion of menstrual endometrium to extracellular matrix: the possible role of integrin alpha(6)beta(1) and laminin interaction.

Previous in-vitro studies have shown that the endometrium preferentially adheres to the extracellular matrix (ECM) of the amnion and peritoneum. This interaction probably involves adhesion molecules, e.g. integrins. We evaluated the expression of integrins in naturally shed menstrual endometrium and the adhesion pattern of this tissue to different components of the ECM. To identify integrins and matrix components involved, blocking studies were performed. Most of the 15 menstrual tissue samples showed positive staining for each of the integrins investigated, except alpha(4)beta(1). Compared with binding to collagen IV, which was set at 100%, adhesion to collagen I was 93% (not significant), to fibronectin 87% (P < 0.05), and to laminin 74% (P < 0.05). Scanning electron micoscopy showed that endometrium adhered to laminin but hardly spread, whereas spreading was observed when layered on the other coatings. Compared with the control (which was set at 100%), incubation with 4B4, a monoclonal antibody against the integrin beta(1) subunit, showed a significant reduction of adhesion (to approximately 50%; P < 0.05) when layered on laminin and a smaller reduction (to 82-86%; P < 0.05) when layered on the other three coatings. Incubation with antibody GOH3 against integrin alpha(6)beta(1) resulted in a similar reduction in adhesion to laminin. Incubation with an RGD peptide significantly reduced adhesion (to 84%; P < 0.05) when plated on fibronectin. In conclusion, antegradely shed menstrual endometrium expresses various integrins. It shows preferential attachment to collagen IV and collagen I, when compared with fibronectin and laminin. Blockage of the integrin beta(1) subunit resulted in greatest disruption to adhesion when layered on laminin, implying that the interaction was mediated by the alpha(6)beta(1) integrin. Since this adhesion was not completely blocked, other mechanisms are likely to be involved.

Adult↗

PubMed2000

Menstruum induces changes in mesothelial cell morphology.

In previous studies, we have shown that menstrual endometrium preferentially adheres to the subepithelial lining of the peritoneum. It remains to be elucidated, however, whether this damage is preexisting or inflicted by the menstrual tissue itself. We hypothesized that the menstrual tissue itself damages the peritoneum. To investigate this, the viability of menstrual endometrial tissue in peritoneal fluid (PF) was evaluated and the morphologic changes in the mesothelial cells were studied by in vitro cocultures of menstruum with mesothelial cell monolayers. Menstruum was collected with a menstrual cup. Endometrial tissue was isolated from the menstruum, resuspended in culture medium or in the cell-free fraction of PF and cultured for 24, 48 or 72 h. A 3(4, 5-dimethylthiazolyl-2)-2,5-diphenyl tetrazolium bromide (MTT) assay was performed to obtain a relative measure of viable adhered endometrial cells. Mesothelial cells isolated from human omental tissue were cultured on Matrigel or uncoated plastic. At confluence, overnight cocultures were performed and scanning electron microscopy was used to evaluate the morphologic changes. The viability of endometrial fragments was 84% (n = 36, p < 0.05), 82% (n = 27, not significant) and 104% (n = 14, not significant) when cultured in the cell-free fraction of PF for 24, 48 and 72 h, respectively, when compared to medium with 10% fetal calf serum. Menstrual endometrial fragments or menstrual serum added to and cocultured with mesothelial cells induced severe morphologic alterations of the latter, including retraction, shrinking and gap formation. Similar morphologic changes were observed when mesothelial cells were cocultured with menstrual endometrial fragments in PF or in culture inserts. Incubation with conditioned medium from cultured menstrual endometrium induced similar but less pronounced changes in morphology. In conclusion, menstrual endometrial fragments remain viable in PF in vitro for at least 72 h. Antegradely shed menstruum induces changes in mesothelial cell morphology, including retraction and shrinking with exposure of the underlying surface. These findings suggest that menstruum is harmful to the peritoneal lining. Therefore, by local destruction of the mesothelial layer, menstrual endometrium is able to create sites for adhesion.

Adipocytes↗

PubMed1999

Adhesion of human endometrial fragments to peritoneum in vitro.

OBJECTIVE: To evaluate the adhesion of endometrial fragments obtained during the proliferative phase of the menstrual cycle to fresh human peritoneum obtained during abdominal surgery. DESIGN: A prospective, descriptive, morphologic and cell biologic study. SETTING: Tertiary care university medical center. PATIENT(S): Six female volunteers. INTERVENTION(S): After endometrial biopsies performed during diagnostic laparoscopy, endometrial fragments were generated by enzymatic digestion and mechanical separation. Peritoneum was obtained during abdominal operations for benign indications. MAIN OUTCOME MEASURE(S): Adhesion of endometrial fragments was studied by histologic examination and scanning and transmission electron microscopy. RESULT(S): After incubation, the mesothelium was intact in some areas, whereas in other areas mesothelial cells were damaged or absent. Adhesion of endometrial fragments was observed only at locations where the basement membrane was exposed. In areas largely denuded of mesothelial cells, endometrial fragments spread over the basement membrane to form monolayers. CONCLUSION(S): Human peritoneum is suitable for studying the adhesion of endometrial fragments. Intact mesothelium prevents the adhesion of endometrial fragments, suggesting that trauma to the mesothelial lining is a prerequisite for endometrial cell adhesion.

Basement Membrane↗

PubMed1999

Adhesion of shed menstrual tissue in an in-vitro model using amnion and peritoneum: a light and electron microscopic study.

We have investigated the adhesion of endometrial tissue isolated from antegradely shed menstrual effluent to amnion and peritoneum. This endometrial tissue was cultured overnight on either side of intact and stripped amnion and on the mesothelial side of peritoneum. Light and electron microscopy were applied to evaluate adhesion. With light microscopy adhesion of endometrial fragments to stripped membranes was observed in nine out of 12 specimens and in 12 out of 13 specimens when layered on the extracellular matrix side of amnion. Adhesion when layered on the epithelial side was seen in only four out of 13 specimens. However, when using scanning electron microscopy adhesion of menstrual endometrial tissue could be visualized in all samples. Numerous adhering fragments were seen when layered on the extracellular matrix side of untreated amnion. On several occasions not only adhesion but also spreading of cells was observed. When layered on the epithelial side of untreated amnion or peritoneum, adhesion was exclusively seen at locations where the epithelium was damaged or absent. These findings were confirmed by transmission electron microscopy. These observations indicate that endometrial tissue isolated from antegradely shed menstrual effluent preferentially adheres to subepithelial structures of amnion and peritoneum. The lack of adhesion to epithelial cells suggests that an intact mesothelial lining prevents adhesion of menstrual endometrial tissue.

Amnion↗

PubMed1998

A randomized comparison of nifedipine and ritodrine for suppression of preterm labor.

OBJECTIVES: To compare the efficacy and safety of nifedipine and ritodrine in preventing preterm labor, and to evaluate maternal side effects and neonatal outcome. STUDY DESIGN: Non-blind, randomized controlled trial RESULTS: A randomized trial of 102 pregnant women with gestational ages under 34 weeks, including 24 with twin pregnancies and 45 on betasympathicomimetic drugs, who had regular uterine contractions with either observed cervical changes or preterm rupture of membranes. After stratification women were randomly assigned to receive either ritodrine intravenously or nifedipine orally. Fifty-five women were randomized to the nifedipine group and 47 to the ritodrine group. As expected, both groups were comparable in terms of several entry variables, including mean gestational age, ruptured membranes, treatment with tocolytic drugs, cervical examination, contraction frequency, age, and twin gestation. Delivery of women in the nifedipine group was delayed for 48 h, 7 days, and until 34 weeks gestation in 33 (60%), 26 (47%) and 21(38%) cases, respectively, compared with 31 (66%), 21(45%) and 11(23%) women in the ritodrine group (no significant difference). Maternal side effects were significantly less common in the nifedipine group than in the ritodrine group, however after 7 days of therapy there was no difference between the two groups. Neonatal outcome was similar in the two groups, with four neonatal deaths in the nifedipine and five in the ritodrine group. CONCLUSIONS: Nifedipine seems to be as effective as ritodrine in the treatment of preterm labor and is associated with less frequent side effects.

Adult↗

PubMed1998

Adhesion of human endometrium to the epithelial lining and extracellular matrix of amnion in vitro: an electron microscopic study.

One of the first steps in the pathogenesis of endometriosis is the attachment of the endometrium to the peritoneal lining. Since the peritoneum is extremely fragile and hard to obtain, amnion has been used as an in-vitro model to study adhesion. Scanning and transmission electron microscopy was applied to evaluate the adhesion of endometrial cells isolated in the proliferative and secretory phases of the menstrual cycle. Endometrial fragments obtained in either phase of the cycle were able to adhere to the extracellular matrix of the amnion. Fragments from proliferative phase endometrium showed active spreading and growth over the matrix surface, whereas fragments from secretory phase endometrium did not. Fragments from proliferative as well as secretory phase endometrium were able to adhere to the epithelial side of the amnion, but only at locations where the amniotic epithelium was damaged or partly absent. These observations indicate that the basement membrane and extracellular matrix provide a suitable substrate for endometrial cell attachment and growth and that endometrial cell adhesion occurs preferentially to subepithelial structures, whereas an intact epithelium prevents the adhesion of endometrial fragments to the amnion.

Amnion↗

PubMed1997

Evaluation of a menstrual cup to collect shed endometrium for in vitro studies.

OBJECTIVE: To evaluate whether a menstrual cup is a suitable instrument to collect antegradely shed endometrium for in vitro studies. DESIGN: A prospective, descriptive, cell biological and immunohistochemical study. SETTING: Tertiary care university medical center. PATIENT(S): Nine female volunteers with regular cycles. INTERVENTION(S): Menstrual effluent was collected with a menstrual cup. Experience with the menstrual cup was described. Cytospin specimens, frozen sections, and cultures were prepared from the obtained menstrual tissue. MAIN OUTCOME MEASURE(S): The acceptability of the menstrual cup. The presence and viability of endometrial tissue was evaluated using immunohistochemical staining and culture outcome. RESULT(S): All women except one described the menstrual cup as acceptable. Menstrual effluent contained single cells, clumps of cells, and glandlike structures. After 5 days of culture, the endometrial tissue appeared to be viable. Immunohistochemistry showed positive staining for vimentin in most cytospin specimens, in all cryostat specimens, and in 10 of 17 cultures. Cytokeratin 18 stained most cytospin specimens, all cryostat specimens, and 10 of 17 cultures. Positive staining for BW495/36 was observed in most cytospin specimens, all cryostat specimens, and 11 of 17 cultures. CONCLUSION: A menstrual cup in an acceptable instrument to collect antegradely shed menstrual tissue. Menstruum contains viable endometrial tissue that can be used for in vitro studies of endometrium and endometriosis.

Adult↗

PubMed1995

Endometrial electrosurgical resection by hysteroscopy in 32 menorrhagic patients: endometrial preparation with a GnRH agonist may have some effect on results.

Our objective was to evaluate the effect of endometrial thinning by GnRH agonists on the results of hysteroscopic endometrial electrosurgical resection. In a prospective study, 32 women were treated with the GnRH agonist goserelin (Zoladex) before hysteroscopic endometrial resection. Endometrial thickness was measured before and after GnRH-a therapy by ultrasound. Short-term results in diminished vaginal blood loss and patient satisfaction were registered. The mean endometrial thickness (ET) before GnRH-a is 3.7 mm and after GnRH-a is 1.9 mm. In 24 cases, ET was reduced by a mean of 2.6 mm, in 1 case, no change was seen, and in 7 cases, ET increased by a mean 1.1 mm. The mean thickness rate (TR = ET before and after GnRH) is 2.7 (range 0.3-11). Fluid resorption during hysteroscopic surgery does not relate to ET or TR. Although the ET after GnRH-a therapy is not related to success or failure of the endometrial resection, there is some evidence that the TR is, probably expressing a more active state of the endometrium. Endometrial thinning by GnRH-a may have an effect on the results of hysteroscopic endometrial resection. In light of the present study and the literature, there seems to be no justification for abandoning preparation of the endometrium before hysteroscopic surgery.

Adult↗