Paracrine function of cultured aortic endothelial cells in spontaneously hypertensive rats

BACKGROUND

Vasoconstrictor and vasodilator release from vascular endothelial cells not only regulates vascular tone but also induces vascular smooth muscle cell proliferation.

METHODS

In order to understand the role of vasoconstrictor and vasodilator release in the development of hypertension in spontaneously hypertensive rats (SHR), aortic endothelial cells were isolated and cultured from 4-week-old and 24-week-old SHR (SHR-4 and SHR-24) and age-matched Wistar-Kyoto rats (WKY-4 and WKY-24) used as control. Prostacyclin (PGI2), endothelin-1 (ET-1) and thromboxane A2 (TXA2) release from cultured endothelial cells in the culture medium, were measured after 30 min with or without treatment with acetylcholine, calcium ionophore A23187 or thrombin.

RESULTS

The results showed that there was no significant difference in ET-1 secretion between SHR-4 and age-matched WKY rats, but ET-1 secretion was about twice as high in SHR-24 as in WKY-24. TXA2 secretion was significantly higher in SHR-4 than in WKY-4 and was also higher than in SHR-24, but there was no significant difference between SHR-24 and WKY-24. The secretion of PGI2 was higher in SHR-24 than in WKY-24 and also higher than in SHR-4 and WKY-4. The prostaglandin PGI2 and TXB2 secretions from all groups of cultured VECs treated with various reagents, acetylcholine, calcium ionophore A23187 or thrombin were increased in similar patterns. However, there was no significantly different response between SHR and WKY VECs.

CONCLUSIONS

Similar levels of ET-1 secreted from endothelial cells between SHR-4 and WKY-4 indicated that ET-1 secretion seems not a crucial factor in early hypertension development in SHR. The high level of TXA2 secretion in SHR-4 may involve in early hypertension development in SHR.

Temporal and spatial sequence expression of cytokeratin K19 in cultured human keratinocyte

The unique cytokeratin K19 specifically expresses in simple epithelial cells, basal cells of non-keratinized stratified squamous epithelium, epidermal cells during the embryonic stage and squamous carcinoma cells, but it is not expressed in adult epidermis. Interestingly, when epidermal cells are cultured in vitro, K19 is re-expressed in the supra-basal layer. K19 expression was used as a marker for epidermal cell growth and differentiation. In order to clarify the temporal and spatial sequential expression in cultured keratinocyte, two-stage human keratinocyte culture systems were used to examine K19 expression in keratinocytes in a proliferation and differentiation stages through immunoblotting and immunohistochemistry assay. According to our results, K19 was not expressed in cultured human keratinocytes in the proliferation stage but was re-expressed in keratinocytes three days after the cultured medium was changed to a differentiation medium. Immunohistochemical observation revealed that K19 was persistently expressed in the supra-basal layer of cultured keratinocytes during first three weeks of culturing, but none was detectable in the basal cell layer. When keratinocytes were cultured with an "inserted cultured dish," K19 was persistently expressed in all layers of keratinocytes nourished by medium both from an inner chamber and an outer chamber. The different expression of K19 in these two different culture systems seemed to indicate that down regulation of K19 expression in keratinocyte was related to the direction of medium supply.

GP-83 and GP-39, two glycoproteins secreted by human epididymis are conjugated to spermatozoa during maturation

Surface glycoconjugates of spermatozoa are modified during epididymal maturation, which is closely related to the development of sperm function. In addition, recognition of surface glycoconjugates is one of very critical events in sperm-oocyte interaction. The binding of carbohydrate-specific lectins to the human sperm surface during epididymal maturation has been investigated. However, the glycoproteins responsible for lectin binding in sperm maturation are not well documented. This study used wheat germ agglutinin (WGA), peanut agglutinin (PNA) and concanavalin A (Con-A) to identify sperm maturation-related glycoproteins in human epididymis. Histochemical localization revealed that the binding sites of WGA, PNA and Con-A were mainly in the principal cells and luminal contents of the human epididymis, but not in the interstitial regions. Each lectin displayed a fairly distinct regional localization. On Western blots probed with WGA and Con-A, glycoproteins of 83 kDa (GP-83) and 39 kDa (GP-39) were identified in the sperm extracts, epididymal fluid and tissue extracts of the corpus and cauda epididymides, but not in the caput. PNA identified GP-83 in the same manner as WGA and Con-A, but did not recognize GP-39. These results suggest that lectin-binding glycoproteins GP-83 and GP-39 found on mature spermatozoa may be secreted by the principal cells of corpus and cauda epididymis, and conjugated to spermatozoa during their transit in human epididymis.

Isolation and characterization of proteins that bind to galactose, lipopolysaccharide of Escherichia coli, and protein A of Staphylococcus aureus from the hemolymph of Tachypleus tridentatus

In this study, we report the isolation and characterization of three novel hemolymph proteins that are believed to be involved in the innate immune response of horseshoe crabs, Tachypleus tridentatus. They include two closely related proteins, one that binds to the protein A of Staphylococcus aureus (PAP) and another that binds to the lipopolysaccharide of Escherichia coli (LBP). PAP binds specifically to staphylococcal protein A (SpA) with a K(D) of 3.86 x 10(-5) M, whereas LBP binds to lipopolysaccharide (LPS) with a K(D) of 1.03 x 10(-6) M. Both PAP and LBP are glycoproteins with an apparent molecular mass of about 40 kDa. N-terminal sequences of PAP and LBP showed 61.9 and 72.2% identity, respectively, to tachylectin-3, a lectin isolated from the amebocyte of T. tridentatus, previously characterized by its affinity to the O-antigen of LPS and blood group A antigen (Muta, T., and Iwanaga, S. (1996) Curr. Opin. Immunol. 8, 41-47). The third protein, a galactose-binding protein (GBP), was found to bind tightly to Sepharose CL-4B and could only be eluted from the column matrix with chaotropic agents, such as 4 M urea or 2 M guanidine hydrochloride. Further analysis indicated that GBP binds to D(+)-galactose with a K(D) of 2.47 x 10(-7) M. N-terminal sequence analysis showed that GBP shared a 50% identity with lectin L-6, identified in the granules of amebocyte of T. tridentatus. (Gokudan, S., Muta, T., Tsuda, R., Koori, K., Kawahara, T., Seki, N., Mizunoe, Y., Wai, S. N. , Iwanaga, S., and Kawabata, S. (1999) Proc. Natl. Acad. Sci. U. S. A. 96, 10086-10091). Lectin-L6 and tachylectin-3 are nonglycosylated intracellular proteins with about half the molecular mass of PAP, LBP, and GBP. GBP also binds to PAP and LBP with K(D) values of 1.25 x 10(-7) and 1.43 x 10(-8) M, respectively, and this binding is enhanced about 10-fold upon the addition of SpA and LPS to form the GBP.PAP.SpA and GBP.LBP.LPS complexes, respectively.

On the biosynthesis of alternating alpha-2,9/alpha-2,8 heteropolymer of sialic acid catalyzed by the sialyltransferase of Escherichia coli Bos-12

Escherichia coli Bos-12 synthesizes a heteropolymer of sialic acids with alternating alpha-2,9/alpha-2,8 glycosidic linkages (1). In this study, we have shown that the polysialyltransferase of the E. coli Bos-12 recognizes an alpha-2,8 glycosidic linkage of sialic acid at the nonreducing end of an exogenous acceptor of either the alpha-2,8 homopolymer of sialic acid or the alternating alpha-2,9/alpha-2,8 heteropolymer of sialic acid and catalyzes the transfer of Neu5Ac from CMP-Neu5Ac to this residue. When the exogenous acceptor is an alpha-2,8-linked oligomer of sialic acid, the main product synthesized is derived from the addition of a single residue of [14C]Neu5Ac to form either an alpha-2,8 glycosidic linkage or an alpha-2,9 glycosidic linkage at the nonreducing end, at an alpha-2, 8/alpha-2,9 ratio of approximately 2:1. When the acceptor is the alternating alpha-2,9/alpha-2,8 heteropolymer of sialic acid, chain elongation takes place four to five times more efficiently than the alpha-2,8-linked homopolymer of sialic acid as an acceptor. It was found that the alpha-2,9-linked homopolymer of sialic acid and the alpha-2,8/alpha-2,9-linked hetero-oligomer of sialic acid with alpha-2,9 at the nonreducing end not only failed to serve as an acceptor for the E. coli Bos-12 polysialyltransferase for the transfer of [14C]Neu5Ac, but they inhibited the de novo synthesis of polysialic acid catalyzed by this enzyme. The results obtained in this study favor the proposal that the biosynthesis of the alpha-2, 9/alpha-2,8 heteropolymer of sialic acid catalyzed by the E. coli Bos-12 polysialyltransferase involves a successive transfer of a preformed alpha-2,8-linked dimer of sialic acid at the nonreducing terminus of the acceptor to form an alpha-2,9 glycosidic linkage between the incoming dimer and the acceptor. The glycosidic linkage at the nonreducing end of the alternating alpha-2,9/alpha-2,8 heteropolymer of sialic acid produced by E. coli Bos-12 should be an alpha-2,8 glycosidic bond and not an alpha-2,9 glycosidic linkage.

Frequent aberration of the transforming growth factor-beta receptor II gene in cell lines but no apparent mutation in pre-invasive and invasive carcinomas of the uterine cervix

The type II transforming growth factor-beta (TGF-beta) receptor (RII) gene located at 3p22 plays an important role in regulating growth and differentiation of epithelium, including that of the uterine cervix. Loss-of-function mutations of RII have frequently been found in gastrointestinal cancers, with a replication-error (RER) phenotype characterized by the presence of microsatellite instability (MI). In this study, genomic PCR, SSCP and DNA sequencing were conducted to investigate the coding sequences of the RII gene in cell lines (n = 5) and tissues (n = 15) of squamous carcinomas of the uterine cervix. Intragenic deletions were noted in 2 of 5 cervical-cancer cell lines (ME180 and HeLa cells). However, no mutation, other than DNA polymorphisms, was found in 15 cervical cancers with either alleleic loss at 3p22 (n = 11) or MI (n = 4). Further analysis of squamous intraepithelial lesions (SIL) with (n = 12) or without (n = 4) MI for the (A)10 change, a prototypic mutation found in over 90% of RER-positive colon cancers, also showed no aberration. Our study concludes that the RII gene is frequently disrupted in cervical-cancer cell lines, but is rarely mutated in CC and SIL tissues, including those showing MI or alleleic loss at 3p22. The underlined mechanism of genomic instability in CC and SIL may thus differ from that of colorectal cancer. The allelic loss at 3p22-24 in CC does not involve the coding sequence of the RII gene. The non-coding sequence of RII or an unidentified gene may be responsible for it.

Thromboxane and prostacyclin in maternal and fetal circulation in pre-eclampsia

OBJECTIVES

A major pathophysiologic change of pre-eclampsia has been attributed to the overproduction of thromboxane A2 (TXA2) mainly from activated platelets. On the other hand, increased biosynthesis of TXA2 has also been reported from preeclamptic placentas. The systemic role of these different sources of TXA2 has not been clarified. The purpose of this study is to define the changes of TXA2 and the antagonizing prostacyclin (PC) in maternal and fetal circulations.

METHODS

The stable metabolites of TXA2 and PC [Thromboxine B2 (TXB2) and 6-keto-prostaglandin F1alpha (6-keto-PGF1alpha), respectively] in the cord and maternal blood of nine patients with pre-eclampsia and nine normal parturients were measured by radioimmunoassay.

RESULT

In normal pregnancy, the cord blood contained much higher TXB2 (1697+/-898 vs. 267+/-128 ng/ml, P < 0.01) and 6-keto-PGF1alpha (266+/-263 vs. 12.5+/-3.9 ng/ml, P < 0.05) levels than the maternal blood. In the preeclamptic state, a marked increase of TXB2 was noted in both maternal and cord blood, reaching levels which were significantly higher than during normal pregnancy (2995+/-1103 vs. 267+/-128 ng/ml in maternal blood, P < 0.0001, and 3197+/-1288 vs. 1697+/-898 ng/ml in cord blood, P < 0.005). A less significant increase in 6-keto-PGF1alpha (134+/-10.8 vs. 12.5+/-3.9 ng/ml, P < 0.05) was also noted in the maternal blood. Moreover, the level of TXB2 correlated with the diastolic blood pressure of preeclamptic patients before and after delivery.

CONCLUSION

The results suggest an abundant source of eicosanoids in the feto-placental circulation, which does not readily cross the placental barrier. In pregnancy complicated with pre-eclampsia, thromboxane level of both fetal and maternal circulations are markedly increased, which may be responsible for the pathophysiologic changes. The lack of adverse systemic effects on the fetus highlights a placental source of TXA2 of transient bioactivity which is rapidly hydrolyzed to non-active TXB2. Federation of Gynecology and Obstetrics

The correlation of blood pressure, age and endothelin-1 binding sites in aortic smooth muscle cells of rats

Spontaneously hypertensive (SHR), Wistar-Kyoto (WKY), and Sprague-Dawley (SD) rats at the ages of 4, 8, 12, 16 and 24 weeks were used to examine the effects of age on the density of endothelin-1 (ET-1) binding sites in aortic smooth muscle cells and systolic blood pressure (SBP). The SBP of the 3 different rat strains was measured, and the maximum binding value (Bmax) and dissociation constant (Kd) of ET-1 binding sites in smooth muscle cells of the thoracic aorta were determined. The results showed that the SBP and Bmax values of SHR, WKY and SD rats increased with age; the SBP and Bmax value at each corresponding age were significantly higher in SHR than in WKY and SD rats, however, there was no significant difference between WKY and SD rats. The relationship of age vs SBP, age vs Bmax, and Bmax vs SBP showed significantly positive correlation in all 3 rat strains. The regression line in the Bmax of endothelin binding sites against SBP in the 3 different rat strains presented a similar slope. These results indicate that SBP, which increased with age, could be related to an increased density of ET-1 binding sites on vascular smooth muscle cells in these 3 different rat strains.

Comparison of endothelin binding sites in cultured aortic smooth muscle cells from spontaneously hypertensive and normotensive rats

Endothelin-1 (ET-1), which is secreted from vascular endothelial cells, is not only a potent vasoconstrictor but also a vascular smooth muscle cell growth factor. The direct effect of ET-1 on vascular smooth muscle cells, mediated via its specific receptor may therefore play an important role in hypertension and atherosclerosis. Our previous studies indicated that ET-1 secretion from cultured aortic endothelial cells from spontaneously hypertensive rats (SHRs) at the prehypertensive stage (4 weeks old) was not significantly different from that of cells from age-matched Wistar-Kyoto (WKY) rats. In this study, the binding of ET-1 to cultured aortic smooth muscle cells from SHRs and WKY rats was studied. Using tissue explant techniques, rat aortic smooth muscle cells from SHRs and age-matched WKY rats of different ages (4 and 24 weeks old) were successfully cultured in vitro. The maximum binding capacity (Bmax) and binding affinity (Kd) of ET-1 to cultured aortic smooth muscle cells were evaluated by a receptor-binding assay. The data revealed that the affinity of ET-1 binding to smooth muscle cells was similar in all 4 groups of experimental rats. However, the Bmax of cultured smooth muscle cells from 24-week-old SHRs was 2.5 times higher than of smooth muscle cells from age-matched WKY rats (8.64 +/- 0.72 vs 3.69 +/- 0.10 fmol/10(6) cells) and 1.5 times higher than in aortic smooth muscle cells from 4-week-old SHRs (8.64 +/- 0.72 vs 5.36 +/- 0.36 fmol/10(6) cells). These results suggest that hypertension in SHRs may be related to a high density of ET-1 receptors on arterial smooth muscle cells.

Enhanced malignant progression of nasopharyngeal carcinoma cells mediated by the expression of Epstein-Barr nuclear antigen 1 in vivo

Nasopharyngeal carcinoma (NPC) is consistently associated with Epstein-Barr virus (EBV) and mostly classified as poorly differentiated squamous cell carcinoma or undifferentiated carcinoma with early metastasis and a rapidly progressive clinical course. The EBV-encoded latent proteins, Epstein-Barr nuclear antigen 1 (EBNA 1) and latent membrane proteins (LMPs), may be expressed in NPC, but their biological effects are poorly understood. EBNA 1 may predispose B lymphocytes to lymphomagenesis in transgenic mice, but its biological effects in NPC are still unknown. This study investigated the biological effects of EBNA 1 by expressing it in an EBV-negative NPC cell line (HONE-1), which was then inoculated into both nude and severe combined immunodeficiency mice. The EBNA 1 caused HONE-1 cells to grow in a less differentiated pattern and to progress more rapidly, as well as increasing their tumourigenicity and metastatic capability. These data suggest that EBNA 1 may play a critical role in the progressive evolution of NPC.

The porcine sperm motility inhibitor is identical to beta-microseminoprotein and is a competitive inhibitor of Na+,K(+)-ATPase

We have isolated a small porcine seminal protein called SMI-1. Our results from peptide sequence, amino acid composition and mass spectral analyses reveal that SMI-1 is identical to porcine beta-microseminoprotein, a protein with unknown function. We also report here that this protein inhibits competitively the activity of Na+,K(+)-ATPase purified from porcine cerebral cortex in a dose-dependent manner. The inhibitory effect could be reversed by the addition of ATP. The half-maximal inhibition was achieved at an inhibitor concentration of 90 microM.

Isolation and cultivation of aortic endothelial cells from spontaneously hypertensive rat with a modified tissue explant technique

In the present study, we successfully established a "tissue explant technique" to obtain high yield and purity of endothelial cells from the aorta of hypertensive and normotensive rats (SHR and WKY). Small pieces of aorta were placed on fibronectin precoated petri dishes. The effects of oxygenation in the tissue preparation stage, tilting of the petri dish during the explanting period and timing of the removal of tissue blocks from petri dishes were evaluated. These procedures appeared to be critical for cell survival, tissue adhesion and minimizing of non-endothelial cell contamination. The cultured endothelial cells were characterized by morphological, immunohistochemical and biochemical examination. The cultured cells from both SHR and WKY rats showed similar endothelial cell character, positive immunofluorescence staining for the von Willebrand factor, and uptake of acetylated low-density lipoprotein (DiI-ac-LDL). The secretory function of prostacylcin I2 (PGI2), thromboxane A2 and endothelin of cultured endothelial cells was measured. The results showed that the secretion of both PGI2 and endothelin was greater in SHR than in WKY rats, but that there was no difference in thromboxane A2 secretion. Therefore, our "tissue explant technique" can provide high yield and purity of endothelial cells with their specific biological function in vitro. It will permit us to further study the role of endothelial cells in the development of hypertension.

The induction of multidrug resistance in human cervical carcinoma cell lines by estrogenic hormones

The role of estrogenic hormones on the induction of drug resistance was studied in cervical cancer cell lines, SiHa and Caski. After the cells were inoculated with estradiol (E2) or diethylstilbestrol (DES) in various dosages, the cell survival rates with adriamycin treatment were examined by MTT (3-[4,5-dimethyl-thiazole-2-yl]-2,5-diphenyl-tetrazolium-bromide) test and the intracellular accumulation of adriamycin was evaluated by flow cytometry. In the same condition, the expression of multidrug resistance gene-1 (mdr-1 gene) was detected either by Northern blot hybridization for mdr-1 mRNA or by immunoblot for P-glycoprotein 170. The data in this study indicated that estrogenic hormones had the capacity to induce drug resistance in cervical carcinoma cell lines. When cells were treated with estrogenic hormones and adriamycin simultaneously, the intracellular accumulation of adriamycin declined and corresponded with the drug resistance. Since the expression of the mdr-1 gene induced by E2 or DES results in drug resistance, it is suggested that the mdr-1 gene in SiHa cells may contain the estrogenic responsive element (ERE) in its regulatory region. However, the mechanism of drug resistance induced by estrogenic hormones in Caski cells is different from SiHa cells due to the absence of mdr-1 gene expression. Despite that, this experiment may provide a model to investigate the relationships between estrogenic hormones and drug resistance in other female genital cancers.

Growth and metabolism of cultured bone cells using microcarrier and monolayer techniques

The traditional in vitro cell culture methods provide bone cells on matrix-coated Petri dishes to grow the cells in a monolayer. This limits the usefulness in situations where there is a need to suspend anchorage dependent cells. To promote the massive production of the cultured cells and to enable the suspension of the cells in a medium, microcarrier cell culture was developed and evaluated. Isolated bone cells from rat calvaria were incubated in a microcarrier culture flask with Cytodex 1. The microcarrier cell morphology was examined by a phase contrast microscope, a scanning electron microscope, and a transmission electron microscope. Cell growth, enzyme markers, and biosynthetic characteristics were examined and compared for microcarrier and monolayer methods. The results indicate that all the characteristics of the bone cells, whether cultured in the Petri dish or microcarrier, were the same. Therefore, the studies of the function and behavior of bone cells still remain useful using the microcarrier system culture.

Establishment and characterization of the transfectable golden hamster embryo fibroblast cell line

A diploid, continuous cell line, Golden Hamster Embryo Fibroblast-III (GHEF-III), which had been passaged for one year, was established essentially by a 3T3 protocol from primary culture of 14-day-gestation Golden Hamster embryo fibroblast cells. The cultured fibroblast exhibited monolayer growth and had contact inhibition. In morphological identification by light microscope (LM), transmission electron microscope (TEM) and immunofluorescence examination (IF), these multipolar and spindle-shaped cells had a large ovoid nucleus, enriched rER and mitochondria in the cytoplasm. On the other hand, the vimentin presented in the cell with a random network and capped around the nucleus. The results indicated that the cultured GHEF-III cells were fibroblast in origin. The cells were free of bacterial and mycoplasma contamination. The doubling time in GHEF-III was about 15 hours. Chromosomal analysis of GHEF-III presented a diploid stem cell line with a modal number of 44. No evidence of transformation of GHEF-III was shown by properties of contact inhibition, no colony formation in soft agar, and no tumor growth in nude mice. The transformation of GHEF-III after transfection with pT24-C3, an oncogenic plasmid, was shown by the evidence of loss of contact inhibition, growth in low serum medium, colony formation in soft agar and tumor growth in nude mice. In vitro transformation testing of these cells may provide valuable data in studying the role of tumor transforming genes in carcinogenesis. Owing to the genetic stability and less spontaneous transformation, this GHEF-III cell line can be utilized as a source of recipient cells in transfection assay.

Human papillomavirus 16 DNA in NIH3T3 cells transformed by colonic cancer cellular DNA

Human papillomavirus (HPV) 16 DNA is closely associated with human cancers. It has been identified as an aetiological agent in cervical cancers and, recently, in colonic neoplasms. To further understand the role of HPV 16 DNA in colorectal carcinogenesis, NIH3T3 cells were transformed with high molecular weight DNA from colonic cancer cells and the expression of HPV 16 DNA detected. Both human Alu and HPV 16 DNA sequences were found in the type II foci of CC-M2T cells by Southern blot hybridisation. Additionally, 100% tumorigenicity in nude mice was seen. This study shows the transfection of HPV DNA from colonic cancers into NIH3T3 mouse cells and suggests that HPV type 16 might be associated with the malignant transformation of colonic cells.

The induction and characterization of antiserum against human placenta 17-beta-hydroxysteroid dehydrogenase

17-beta-Hydroxysteroid dehydrogenase was purified from human placenta. The purification process included the following steps: 50% saturated ammonium sulfate precipitation; heat treatment; affinity column chromatography; and preparative SDS gel electrophoretic elution. This enzyme was also characterized by HPLC gel filtration and two dimensional gel electrophoresis with isoelectrofocusing. The results indicate that the molecular weight of these enzymes in their native condition is around 68 kDa and 34 kDa in SDS PAGE. Therefore, the active form of the enzyme is an identical dimmer in nature. There are three charged isomers as demonstrated by isoelectrofocusing. The antiserum against the 17-beta-HSD was induced by injection of purified human placenta 17-beta-HSD in rabbits. The antiserum was collected and characterized by ELISA, immunohistochemistry, immunoblot and immunoprecipitation tests. The results showed that the antibody titer was over 1:12,800, and specificity against human placenta 17-beta-HSD was also observed.

The secretion of two sperm maturation-related glycoproteins in BALB/c mouse epididymis

A well-developed Golgi apparatus and rough and smooth endoplasmic reticulum in the principal cells of the mouse epididymis indicate active protein synthesis. Studies have shown that epididymal secretions are essential for sperm maturation. In a previous study, two wheat-germ agglutinin (WGA)-binding glycoproteins, GP-49 and GP-83, were identified on the surface of mature mouse sperm. In this study, synthesis and secretion of these two glycoproteins were investigated. Apparent WGA-binding was found on the stereocilia and in the apical region of principal cells in the corpus and cauda of epididymis. Post-fixation and pre-embedding cytochemical localization revealed that WGA-binding sites were situated in the Golgi apparatus, multivesicular bodies and stereocilia of principal cells. GP-49 and GP-83 were identified in the Nonidet P-40 homogenates of corpus and cauda epididymidis. In the epididymides of which ductuli efferentes had been ligated for more than 4 weeks, no sperm were found in the lumina of epididymal tubules. WGA-binding sites were present in the corpus and cauda; GP-49 and GP-83 were identified in tissue homogenates of the corpus and cauda as well. These findings suggest that GP-49 and GP-83 of mature sperm may be secreted by the principal cells of the corpus and cauda. These two molecules apparently conjugate to sperm whilst sperm transit through the epididymis.

Human papillomavirus type-related DNA and c-myc oncogene alterations in colon cancer cell lines

Although squamous-cell epithelium is the most frequent target site of human papillomavirus (HPV) infection, a similar infection is demonstrated in columnar epithelial cells in this paper. The papillomavirus expression in three cell lines was detected in colorectal adenocarcinoma of Chinese patients. The HPV-16 and HPV-18 DNA sequences were found in colorectal cancer cell lines, which might suggest the correlation of HPV to the etiology of colorectal cancers. In addition, c-myc oncogene was identified by amplification in all three colorectal cancer cell lines, but only normal germ-line fragments were found in control tissue. The correlation between HPV and c-myc, and the implications of these findings in colorectal cancers are also discussed.

Identification of two maturation-related, wheat-germ-lectin-binding proteins on the surface of mouse sperm

Epididymal maturation is essential for mammalian sperm to develop fertility. Wheat germ agglutinin (WGA), a lectin which specifically recognizes N-acetyl-glucosamine and sialic acid, was used to investigate membrane characteristics of epididymal sperm in the mouse. Histochemical and cytochemical localization revealed that WGA-binding sites were increased as sperm became mature. The binding sites were mainly localized in the plasma membrane of the anterior acrosome and tails. On Western blots of NP-40 extracts, two WGA-binding glycoproteins, GP-49 and GP-83, were identified on the sperm recovered from both corpus and cauda epididymidis. GP-83 was removed from the sperm surface by centrifugation and resuspension in phosphate-buffered saline (PBS) three times. GP-49 was resistant to centrifuging at 400 g for 5 min up to seven times and the treatment with 1M NaCl in PBS. These observations suggest that GP-49 is very likely an intrinsic membrane protein of the sperm, whereas GP-83 is an extrinsic protein.

Mechanism of estrogen-induced 17-beta-hydroxysteroid dehydrogenase in ovariectomized rat uterus

Estradiol (E2), progesterone or medroxyprogesterone acetate can induce biosynthesis of the 17-beta-hydroxysteroid dehydrogenase (17-beta-HSD) in the mammalian uterus. For further understanding the 17-beta-HSD induction which may be mediated by the conjugation of the E2 to its receptor, premature ovariectomized rats were treated with E2, or with a synthetic steroid, diethylstilbestrol (DES), an agonist for the E2 receptor but not a substrate for 17-beta-HSD. Histological observation and uterus weight were examined as parameters to evaluate uterine response to those hormones at different durations of treatment. The 17-beta-HSD in ovariectomized rat uterus of each group was also examined by histochemical and biochemical assays. The results showed that the 17-beta-HSD activity in the uterus can be induced by E2 or DES, after daily treatment for 1, 14 and 28 days, but much higher in DES treated animals. The uterus weight demonstrated a "negative linear correlation" to the enzyme activity in all E2 treated groups, but not in DES or control rats. Accordingly, it was indicated that the 17-beta-HSD induction was regulated by conjugation of E2 or DES to its receptor. Therefore, we believe that the 17-beta-HSD gene in the rat uterus is another estrogen responsive gene.

Functional evaluation of cultured rabbit osteoblast-like cells

For the improvement of the adult osteoblast culture, the osteoblasts of young adult rabbit endosteal from long bones were isolated by collagenase digesting separation. 0.1% of type-I collagen precoated culture flasks were used as substrate for isolated bone cell growth. Morphological examination of cultured cells under a phase-contrast microscope, SEM and TEM observations showed a structure similar to osteoblast in vivo. Histochemical examination of alkaline phosphatase demonstrated 97% purity of cultured osteoblasts. The presence of calcium deposit activity in cultured cells was demonstrated by Van Kossa stain. High activity of alkaline phosphatase and inorganic pyrophosphatase in cultured osteoblasts as determined by biochemical analysis. High calcium uptake in cultured osteoblasts was demonstrated by radioisotope labelled 45CaCl12. According to these methods, it was indicated that the cells isolated from young rabbit long bone endosteal were osteoblast-like and still maintained their biological function. Our system for culturing osteoblast-like cells is a successful attempt in growing bone tissue in vitro starting from isolated bone cells. Therefore, this modified method for bone cell culture on collagen precoated culture flasks could be used as the experimental model in studies concerning the osteoblasts in vitro.

17-beta-Hydroxysteroid dehydrogenase in rabbit bone marrow

Because of the general presence of 17-B-hydroxysteroid dehydrogenase (17-B-HSD) in animals and human erythrocytes, it is very likely that this enzyme is also present in the erythrocyte precursor cells in bone marrow. Adult male white New Zealand rabbits were used to demonstrate the existence of the 17-B-HSD in bone marrow cells and to evaluate the biological function of 17-B-HSD in the erythropoietic system in bone marrow. Anemia was artificially induced in these animals in order to stimulate the proliferation of erythropoietic cells. This was accomplished by bleeding or by intra-peritoneal injection of 40 mg/kg of phenylhydrazine. The 17-B-HSD activities were then examined by histochemical and biochemical assays. The results showed a two to three-fold increase of the enzyme activities in both peripheral erythrocytes and bone marrow cells of anemic animals. Our experiments further demonstrate the fine control of erythropoiesis. The enzyme, which favors the conversion of oestradiol to oestrone, is itself boosted by an anemic state. As a result, the inhibitory action of hemopoiesis by oestradiol was relieved.

Effect of epidermal growth factor on the sheet formation of the human keratinocyte in cell culture

Epidermal growth factor is an important element in maintaining keratinocyte proliferation and maturation. To evaluate its effect on keratinocyte growth in vitro, human foreskins were cultured. The epidermal keratinocyte growth in culture was separated into two stages by a conditional medium: the proliferation stage, in which the cells were maintained in a monolayer; and the differentiation stage, in which the cells grew to stratification and keratinization. The keratinocytes were cultured in various concentrations of epidermal growth factor, and their morphology and growth behavior were closely observed. Our results demonstrated that cultured keratinocytes grew in a confluent layer under the influence of epidermal growth factor. In contrast, in a culture without epidermal growth factor, the proliferation rate of cultured keratinocytes slowed down and eventually the cells stopped growing. During serum stimulation, with or without additional exogenous epidermal growth factor, the cultured keratinocytes grew continuously to the normal terminal differentiation. Under this two-stage culture model, the cultured keratinocytes could grow into an intact sheet of graftable epidermis.

Cytochemical localization and biochemical analysis of the enzyme markers in human hepatoma cell lines

Three enzyme makers, glucose-6-phosphatase, ATPase and gamma-glutamyl transpeptidase, have been used in studying carcinogenesis of hepatocellular carcinoma. They have been investigated in animal models and human hepatocellular carcinoma in vivo and in vitro. But the inconsistent levels of these three enzymes associated with this type of carcinoma raised the possibility that the carcinoma cells might have derived from the cells originating from different stages of differentiation. To evaluate this possibility, three human cell lines, Hep G2, Hep 3B, and HA 22T, all thought to be arrested in different stages of differentiation based on their biochemical and morphological characteristics, were used as models. The three enzyme markers glucose-6-phosphatase, ATPase and gamma-glutamyl transpeptidase were examined cytochemically and biochemically. Our results showed that there was no correlation between the ATPase levels and the stages of the cell line's differentiation. But both glucose-6-phosphatase and gamma-glutamyl-transpeptidase were higher in cells that were more differentiated.

Effects of prostaglandin E2 on alveolar bone resorption during orthodontic tooth movement

Twenty Sprague-Dawley rats weighing 280-300 g were divided into two groups of ten animals each. They were treated by daily submucosal injections of 50 micrograms prostaglandin E2 (PGE2) per kilogram body weight into the region below the apex of the left first maxillary molar (experimental), or vehicle into the region below the apex of the right first molar (control), for a period of 5 days. The animals of the first group were sacrificed immediately following the treatment period, while those of the second group were sacrificed 5 days after the treatment period. Twenty-two hours prior to sacrifice, a piece of latex orthodontic elastic was secured to the adjacent area between the first and second maxillary molars of both sides of each rat by using two mosquito hemostats. The periodontal ligament (PDL) mesial to the mesiobuccal root of the first maxillary molar was assayed for changes in PDL cell factors. The results showed that immediately following the 5-day treatment period the left PDL had a significant decrease in the total number of fibroblasts and a significant increase in the total number of both osteoclasts and nuclei per osteoclast, while no significant changes in the osteoblasts when compared with those of the right control PDL. The left PDL of animals which were sacrificed 5 days after the treatment period revealed a significant decrease in the number of total fibroblasts and only a slight decrease in both numbers of total osteoclasts and total nuclei per osteoclast, but again no significant changes in osteoblasts when compared with those of the right control PDL.(ABSTRACT TRUNCATED AT 250 WORDS)

Presence of episomal and integrated human papillomavirus DNA sequences in cervical carcinoma

Thirty surgical samples of squamous cell carcinoma of the cervix obtained from Chinese women were analysed for the presence of human papillomavirus (HPV) types 16 and 18 using Southern blot hybridization procedure. HPV16 was detected in 53% while HPV18 was found in only 6% of the samples analyzed. When compared with other reports, variation in the geographic distribution of these two HPV types in association with cervical carcinoma is noted. Thirty-seven and a half percent of the HPV16-positive samples contained this HPV type in episomal form and an equal number in cellular DNA-integrated form. The simultaneous presence of both episomal and integrated forms was found in the remaining 25% of the positive samples. The two HPV18-positive cases harbored only episomal viral genome and were not superinfected by HPV16. Analysis of the HPV16 integration samples showed that single integration events had probably occurred and some of the viral sequences had been lost on or subsequent to integration.

The effect of nitroimidazoles on the oxygen consumption rate and respiratory control ratio of beef heart mitochondria

The neurotoxic effect of the nitroimidazole radiosensitizers misonidazole (MISO) and desmethylmisonidazole (DMM) has seriously compromised their clinical effectiveness. We compare here the effect of MISO and DMM on oxygen consumption in purified beef heart mitochondria. MISO has been found to significantly increase the oxygen consumption rate and decrease the respiratory control ratio in isolated mitochondria when incubated in the presence of the NAD+ dependent substrate, beta-hydroxybutyrate. DMM has a similar but less pronounced effect than MISO on these respiratory parameters. When mitochondria were incubated in the presence of these radiosensitizers for 8, 15, 30, 45, and 60 minutes, the oxygen consumption rate was decreased when succinate, a FAD dependent substrate, was added following the incubation. This decrease, which is both time and dosage dependent, is equivalent for MISO and DMM.

The effect of nitroimidazoles on glucose utilization and lactate accumulation in mouse brain

The radiation sensitizers misonidazole (MISO) and desmethylmisonidazole (DMM) can produce central and peripheral neuropathy in patients and laboratory animals. Behavioral and pathological investigations have indicated that in the central nervous system this primarily involves the cochlear and vestibular systems. Nitroimidazoles can also interfere with glycolysis in vitro under aerobic and anaerobic conditions. In the present work we have studied the effect of MISO or DMM on lactate production and glucose utilization in mouse brain. It is observed that these compounds result in a 25% inhibition of lactate production in brain slices relative to the control at a 10 mM level. Additionally, MISO (1.0 mg/g/day) or DMM (1.4 mg/g/day) were administered daily (oral) for 1, 4, 7, or 14 days to examine the effect of these two drugs on the regional glucose utilization in C3Hf mouse brain. Five microcuries of 2-deoxy[14C]glucose was given following the last drug dose and autoradiographs of serial brain sections were made and analyzed by a densitometer. Following a single dose of either MISO or DMM, no significant differences in glucose uptake were observed when compared with controls. However, following 4, 7, and 14 doses the rate of glucose utilization was significantly reduced in the intoxicated animals. Larger reductions were measured in specific regions including the posterior colliculus, cochlear nuclei, vestibular nuclei, and pons with increasing effects observed at later stages. These results share a degree of correspondence with the regional brain pathology produced by these nitroimidazoles.

Behavioural and ultrastructural studies of desmethylmisonidazole-induced neurotoxicity in mice

The hypoxic cell radiosensitiser desmethylmisonidazole (DMM, Ro-05-9963) was administered orally to C3Hf female mice at three different dose levels (1.4, 1.6 and 1.8 mg g-1 day-1). Behavioural and morphological end-points were used to evaluate the neurotoxicity of this compound at these doses. The behavioural changes present at all three dose levels appeared when the total dose approached approximately 19 mg g-1. The behavioural changes initially appeared and developed to a severe state rapidly (24 to 48 h). A pattern of haemorrhagic necrosis was observed in the brain stem and cerebellum, but no pathology was observed in the cerebrum. Peripheral nerve degeneration was also evident and appeared concurrent with the central pathology. DMM appears to affect both the central and peripheral nervous systems at the same time at these dose levels. This is in some degree different from previous experience with misonidazole where peripheral damage distinctly precedes central effects. The development of the disorder appeared to be more rapid and severe when compared with earlier experience with misonidazole.

Haemolytic anaemia in rhesus monkeys induced by methylcellulose

The rhesus monkey was evaluated in its haemopoietic and histological response to intraperitoneal injections of methylcellulose. The haematologic alterations included a mild haemolytic anaemia, lymphopaenia, monocytosis, a shortened survival of Cr51 -labelled autologous erythrocytes (17 . 1 vs 13 . 3 days, P less than 0.025) and normoblastic hyperplasia of the bone marrow. There was a diffuse sequestration of the polymer in the phagocytic cells of the spleen, liver, bone marrow, lymph nodes and adrenal glands. The renal glomerular endothelium also consistently stored this material. Overt splenomegaly was not induced. The monkey appears to present, along with other animals, a rather species-specific response to methylcellulose that is accompanied by fundamental responses observable in all subjects.

Nitroimidazole inhibition of lactate production in CHO cells

Misonidazole (MISO) and desmethylmisonidazole (DMM) inhibit lactate production in CHO cells under aerobic conditions. This inhibition is time and dose dependent. At the 20 mM level DMM is stronger in producing this inhibition of lactate than is MISO. This inhibiton of lactate production suggests that these compounds are capable of inhibiting the glycolytic pathway. The resultant energy deficiency may be an explantation for the toxicity of these compounds under hypoxic as well as aerobic conditions. The increased dependency on glycolysis of hypoxic cells may correspond to the analogous increase in toxicity of hypoxic cells to nitroimidazoles.

Heat shock proteins and biological response to hyperthermia

Thermotolerance is of significant interest because the resistance of pre-heated cells greatly surpasses the resistance of control cells. The induction of protein synthesis following a temperature shock (12 min, 45 degrees C) which produces thermotolerance is examined using SDS polyacrylamide gel electrophoresis. It was observed that the synthetic rates of certain proteins following heat shock significantly exceeded their synthetic rates in control (non-heat shocked) cells. The most strongly induced bands were observed at 68,000, 89,000 and 110,000 daltons. The induction of these proteins was blocked by inhibitors of transcription (actinomycin D) or translation (cycloheximide). This phenomenon strongly resembles the heat shock induction of gene transcription well studied in Drosophila melanogaster. The strong induction of gene transcription well studied in Drosophila melanogaster. The strong correlation between the kinetics of the induction of these heat shock proteins and the kinetics of thermotolerance induction is discussed.