[Changes of Kupffer cell DNA and RNA synthetic functions after partial hepatectomy in cirrhotic rats]

We studied the changes of DNA and RNA synthetic functions of regenerating liver cells after partial hepatectomy in cirrhotic rats and discussed the relationship between liver regeneration and liver functional failure. Seventy healthy male Wistar rats weighing 200 approximately 250 g, were randomized into sham-operated (SO), partial hepatectomy in cirrhotic rats (C-PH) and partial hepatectomy in normal rats (N-PH). The left and middle lobes were dissected. The synthetic DNA peak of Kupffer cells (KC) in the G2 and M phase in C-PH was found after 24 hr of operation. The regenerating index peak of KC was at 48 hr after operation, which was higher than the other groups, but the liver weights in C-PH was lower than that in the N-PH at 1 week after operation. The RNA content of KC markedly decreased and returned to normal levels at 1 week after operation. We think that KC functions are suppressed after partial hepatectomy in cirrhotic rats. It is an important cause of hepatocyte regeneration function decrease and liver functional failure for delay of liver cell regeneration "start" and the regeneration cell cycle.

[The role of urokinase type plasminogen activator in invasion of bile duct carcinoma]

OBJECTIVE

To study the role of urokinase type plasminogen activator (u-PA) in the invasive process of bile duct carcinoma.

METHODS

The secretion of u-PA and the invasive potential of tumor cell in vitro in a newly established cell line of bile duct carcinoma, QBC939, were observed by using an amnion invasion culture system.

RESULTS

QBC939 cells secreted u-PA with high invasive potential. The inhibitors of u-PA and plasmin, tranexamic acid and 6-aminocaproic acid, obviously inhibited the u-PA activity and the invasive potential of QBC939 cells.

CONCLUSION

u-PA is one of the important enzymes in tumor invasion. Inhibiting u-PA or plasmin may be a prospective therapy for tumor treatment.

ICE-LAP6, a novel member of the ICE/Ced-3 gene family, is activated by the cytotoxic T cell protease granzyme B

Members of the ICE/Ced-3 gene family are likely effector components of the cell death machinery. Here, we characterize a novel member of this family designated ICE-LAP6. By phylogenetic analysis, ICE-LAP6 is classified into the Ced-3 subfamily which includes Ced-3, Yama/CPP32/apopain, Mch2, and ICE-LAP3/Mch3/CMH-1. Interestingly, ICE-LAP6 contains an active site QACGG pentapeptide, rather than the QACRG pentapeptide shared by other family members. Overexpression of ICE-LAP6 induces apoptosis in MCF7 breast carcinoma cells. More importantly, ICE-LAP6 is proteolytically processed into an active cysteine protease by granzyme B, an important component of cytotoxic T cell-mediated apoptosis. Once activated, ICE-LAP6 is able to cleave the death substrate poly(ADP-ribose) polymerase into signature apoptotic fragments.

Cytotoxic T-cell-derived granzyme B activates the apoptotic protease ICE-LAP3

Cytotoxic T lymphocytes (CTLs) and natural killers (NK) cells provide immune surveillance against viruses and neoplasms, and play a central role in the pathogenesis of autoimmune disease, AIDS and graft rejection. Thus, it is important to understand the precise molecular mechanism(s) whereby cytotoxic lymphocytes destroy susceptible target cells. Granule-mediated cytotoxicity requires a combination of both perforin and granzyme B. Perforin polymerizes to form transmembrane channels and presumably allows granzyme B access to target cell substrates, which until recently, were unknown. One clue to the identity of the physiological substrate(s) activated by granzyme B comes from its unusual specificity for cleaving synthetic substrates after aspartate residues. Members of the ICE/CED-3 family of cysteine proteases are prime candidates as they are important apoptotic effectors and are expressed as zymogens, which can be processed to form active heterodimeric enzymes after cleavage at specific aspartate residues. Previous studies have shown that granzyme B proteolytically activates the cell death effector Yama/CPP32/apopain (referred to here as Yama). Here we report that granzyme B also activates ICE-LAP3/Mch3/CMH-1 (referred to here as ICE-LAP3), which, along with Yama and Mch2, forms a subset of the ICE/CED-3 family of cysteine proteases most closely related to the Caenorhabditis elegans cell death gene, CED-3. Importantly, Jurkat T cells incubated with granzyme B and a sublytic concentration of perforin undergo apoptosis, which is preceded by the activation of endogenous ICE-LAP3. Thus, we propose that granzyme B mediates apoptosis by directly engaging the target cell's death effector machinery, which is probably composed of an arsenal of intracellular, CED-3-like cysteine proteases.

[Diagnosis of uterine diseases by combined hysteroscopy and ultrasonography]

OBJECTIVE

To investigate the diagnostic value of combined hysteroscopy with ultrasonography.

METHODS

477 patients were diagnosed by hysteroscopy, ultrasonography, or hysteroscopy combined with ultrasound. The results of the 3 groups were compared with the findings after operations.

RESULTS

This study indicated to diagnose intrauterine lesions, intramural diseases or pelvic disorders, hysteroscopy with ultrasonography was significantly better than either methods alone. The accuracy rate, false positive rate as well as false negative rate were 98.32%, 1.26% and 0.04% respectively.

CONCLUSION

Hysteroscopy is used for diagnosis and treatment of intrauterine lesions, and ultrasonography is difficult to show actual location of lesions within uterine cavity. The present study has shown that hysteroscopy combined with ultrasound could increase the effectiveness and accuracy of uterine diseases' diagnosis.

Molecular ordering of the cell death pathway. Bcl-2 and Bcl-xL function upstream of the CED-3-like apoptotic proteases

Genetic analyses of Caenorhabditis elegans has identified three genes that function in the regulation of nematode cell death. Mammalian homologs of two of these genes, ced-9 and ced-3, have been identified and comprise proteins belonging to the Bcl-2 and ICE families, respectively. To date, it is unclear where the negative regulators, ced-9 and bcl-2, function relative to the death effectors, ced-3 and the mammalian ced-3 homologs, respectively. Here, the molecular order of the cell death pathway is defined. Our results establish that Bcl-2 and Bcl-xL function upstream of two members of the ICE/CED-3 family of cysteine proteases, Yama (CPP32/apopain) and ICE-LAP3 (Mch3).

Cholesterol homeostasis is modulated by amphiphiles at transcriptional and post-transcriptional loci

A variety of amphiphiles inhibit plasma membrane cholesterol esterification and induce 3-hydroxy-3-methylglutaryl-coenzyme A reductase accumulation in cultured cells; among these are steroids, hydrophobic amines, phenothiazines, ionophores, colchicine, and lysophosphatides. It has been proposed that these amphiphiles signal a sterol deficiency to regulatory sites by blocking the movement of plasma membrane cholesterol into the cell (Lange, Y., and Steck, T. L. 1994. J. Biol. Chem. 269: 29371-29374). If this were the case, these agents also should enhance transcription of sterol responsive genes and stabilize 3-hydroxy-3-methylglutaryl-coenzyme A reductase. As a test of this hypothesis, the effect of the amphiphiles on such transcriptional and post-transcriptional events was assessed. A mouse embryo cell line was transfected with a construct containing the promoter for the human low density lipoprotein receptor upstream of the DNA sequence coding for chloramphenicol acyltransferase (CAT). Incubation of these cells for 7-18 h with the aforementioned agents caused the level of expression of the promoter/CAT construct to increase 2- to 9-fold. We showed further that the amphiphiles stimulated 3-hydroxy-3 methylglutaryl-coenzyme A reductase activity by increasing gene transcription as well as by decreasing degradation of the enzyme. These are the predicted homeostatic responses to cell cholesterol deficiency. These findings support the hypothesis that certain amphiphiles falsely signal a cholesterol deficiency to the intracellular sites regulating cholesterol homeostasis.

ICE-LAP3, a novel mammalian homologue of the Caenorhabditis elegans cell death protein Ced-3 is activated during Fas- and tumor necrosis factor-induced apoptosis

Members of the ICE/ced-3 gene family have been implicated as components of the cell death pathway. Based on similarities with the structural prototype interleukin-1 beta-converting enzyme (ICE), family members are synthesized as proenzymes that are proteolytically processed to form active heterodimeric enzymes. In this report, we describe a novel member of this growing gene family, ICE-LAP3, which is closely related to the death effector Yama/CPP32/Apopain. Pro-ICE-LAP3 is a 35-kDa protein localized to the cytoplasm and expressed in a variety of tissues and cell lines. Overexpression of a truncated version of ICE-LAP3 (missing the pro-domain) induces apoptosis in MCF7 breast carcinoma cells. Importantly, upon receipt of a death stimulus, endogenous ICE-LAP3 is processed to its subunit forms, suggesting a physiological role in cell death. This is the first report to demonstrate processing of a native ICE/ced-3 family member during execution of the death program and the first description of the subcellular localization of an ICE/ced-3 family member.

Calorimetric monitoring of lyophilization

This paper describes an apparatus and method for monitoring the lyophilization of a formulation by using calorimetric measurements. From calorimetric measurements, the energy transferred during each phase of the process can be determined. A brief review of the existing monitoring methods shows that they possess no direct relationship to the thermal energy that represents the real driving force for the lyophilization process. A general description of the apparatus is presented with special emphasis made on the sensor construction and calibration. The means for determining the heat transfer rate (Qm) and total energy (Hm) for each step of the process are described. The use of calorimetric measurements are demonstrated by showing actual thermographs of freezing, primary drying and secondary drying processes for several formulations. Some key advantages of calorimetric monitoring of the lyophilization process are demonstrated by accurately determining the completion of the primary drying and detection of exothermic reactions during the secondary drying.

The Ret receptor protein tyrosine kinase associates with the SH2-containing adapter protein Grb10

Ret is a receptor protein tyrosine kinase that has been implicated in the development of the enteric nervous, endocrine, and renal systems. Mutations associated with multiple endocrine neoplasia types 2A and 2B (MEN 2A and 2B) have been shown to activate the intrinsic kinase and transforming ability of ret (Santoro, M., Carlomagno, F., Romano, A., Bottaro, D. P., Dathan, N. A., Grieco, M., Fusco, A., Vecchio, G., Matoskova, B., Kraus, M. H., and Paolo DiFiore, P. (1995) Science 267, 381-383). Using the cytoplasmic domain of Ret as bait in a yeast two-hybrid screen of a mouse embryonic library, it was discovered that the src homology 2 (SH2) domain containing protein Grb10 bound Ret. Grb10 belongs to an emerging family of SH2 containing adapter proteins, the prototypical member being Grb7. Using glutathione S-transferase fusion proteins, it was demonstrated that the SH2 domain of Grb10 specifically interacted with Ret. Additionally, using an EGFR/Ret chimera, it was shown that Grb10 bound Ret in an activation dependent manner in vivo. This is the first description of a receptor protein tyrosine kinase that utilizes Grb10 as a signaling intermediate.

Characterization of a novel Src-like adapter protein that associates with the Eck receptor tyrosine kinase

The Eph family of receptor protein tyrosine kinases (RPTKs) is the largest family of RPTKs. The signal transduction pathways initiated by this family have only recently begun to be explored. Using a yeast two-hybrid screen to identify molecules that interact with the cytoplasmic domain of Eck, it was previously shown that activated Eck RPTK bound to and stimulated phosphatidylinositol 3-kinase (Pandey, A., Lazar, D.F., Saltiel, A. R., and Dixit, V.M. (1994) J. Biol. Chem. 269, 30154-30157). Also isolated from this same screen was a novel protein containing SH3 and SH2 adapter modules that had striking homology to those found in the Src family of non-receptor tyrosine kinases. However, unlike other Src family members, it lacked a catalytic tyrosine kinase domain. Hence, this protein was designated SLAP for Src-like adapter protein. Using glutathione S-transferase fusion Proteins, it was demonstrated that SLAP bound to activated Eck receptor tyrosine kinase. Therefore, SLAP is a novel candidate downstream signaling intermediate and the first member of the Src family that resembles an adapter molecule.

Tumor necrosis factor-alpha modulates monocyte/macrophage apoprotein E gene expression

apo E has been shown to modulate cholesterol balance in arterial wall cells. Production of apo E by macrophages in atherosclerotic plaques could thereby influence the development of the plaque lesion. Cytokines, including TNF alpha, have been identified in human lesions, therefore, we undertook a series of studies to evaluate the effect of TNF alpha on monocyte/macrophage apo E production. The addition of TNF alpha to freshly isolated human monocytes led to a four- to fivefold increase of apo E mRNA abundance. The addition of TNF alpha to fully differentiated macrophages either had no effect or modestly inhibited apo E mRNA expression. THP1 human monocytic cells also responded to TNF alpha in a phenotype-specific manner. Treatment of these cells with TNF alpha produced a dose- and time-dependent increase in apo E mRNA. This increase was reflected in apo E synthesis and was associated with inhibition of DNA synthesis, and with induction of c-fos and ICAM-1 gene expression. Cell-permanent analogues of ceramide did not reproduce TNF alpha effect on apo E, but antagonists of protein kinase C did inhibit its effect. TNF alpha induction of apo E mRNA abundance was associated with stimulation of apo E promoter-dependent gene transcription. In summary, TNF alpha stimulates apo E gene transcription, mRNA abundance, and protein synthesis in the monocyte/macrophage in a phenotype-specific manner. Such regulation could significantly modify the amount of apo E present in vessel wall lesions.

Crop and midgut filling and emptying in a female Phormia regina (Diptera: Calliphoridae) fed a liver diet

To study the role of the crop in protein storage, crop and midgut filling in female Phormia regina (Meigen) was measured volumetrically and the soluble protein content determined. During a 4-h feeding period on homogenized liver, nonligated females consumed and stored enough protein in the crop and midgut to develop a normal compliment of eggs. Within 26 h from the onset of feeding, 75% of the protein content of the crop and a similar amount from the midgut were emptied. Neck ligation or sham neck ligation 7 h after females fed to repletion slowed but still allowed delivery of sufficient protein for egg development.

Age-related alterations of proteoglycan in mouse tracheal cartilage matrix: an electron histochemical analysis with the cationic dye of polyethyleneimine

Age-related alterations of the proteoglycans (PGs) contents and size were observed in the tracheal cartilage matrix of ddY mice at various ages with the cationic dye of polyethyleneimine (PEI). In young animals (aged 1 day to 1 month after birth), the PGs content and size increased, resulting in the formation of the territorial matrix (TM) and the decrease of the space between the PEI aggregates and the collagen fibers. In 1 month old mice, the TM could be distinguished from the interterritorial matrix (ITM). In adult mice (from 2 to 6 months), the PGs content and size kept stable, but the rearrangement of the PGs and collagen fibers was observed. From 6 months of age on, the decrease of PGs content and size occurred mainly in the ITM. The developing stopping sign was recognized in 1 month and the senile sign from 6 months in the ddY mice as for the complete formation of the TM in 1 month and the decrease of the PGs content and size from 6 months. These results demonstrated the age-related alteration of PGs in the ultrastructural level first and could contribute to the aging study of the tracheal cartilage.

Postnatal development and aging of esophageal epithelium in mouse: a light and electron microscopic radioautographic study

DNA synthesis and fine structure of the esophageal epithelium of ddY mouse in different age groups, from neonatal to senescent, were investigated by light and electron microscopic radioautography after 3H-thymidine labeling in vitro. At 1-3 days after birth, the esophagus was lined with two cell types, ciliated and nonciliated cells. From 1 week on, ciliated cells could not be found. At 2 weeks, the superficial cells still possessed nuclei and short microvilli on the apical plasma membranes. From 1 month, the superficial cells became keratinized and the microvilli on the apical plasma membrane disappeared. With aging of the mice, the epithelia became markedly thick. These results show that disappearance of ciliated cells, keratinization of superficial cells and increase of the thickness are the main changes in structure of mouse esophageal epithelium from neonatal to senescent ages. By light microscopic radioautography, labelled cells were almost confined in the basal layer, regardless of the aging stages. The highest labeling index was recorded at 1 day after birth, then decreased with age. By electron microscopic radioautography, silver grains indicating DNA synthesis were observed in nuclei. As compared with those of unlabelled cells in the basal layer, the nuclei and nucleoli of labelled cells were larger, with fewer cell organelles. The present study provides, for the first time, the basic quantitative data regarding cell proliferation of mouse esophageal epithelium from neonatal to senescent stage.