Fibroblast growth factor 2 control of vascular tone

Vascular tone control is essential in blood pressure regulation, shock, ischemia-reperfusion, inflammation, vessel injury/repair, wound healing, temperature regulation, digestion, exercise physiology, and metabolism. Here we show that a well-known growth factor, FGF2, long thought to be involved in many developmental and homeostatic processes, including growth of the tissue layers of vessel walls, functions in vascular tone control. Fgf2 knockout mice are morphologically normal and display decreased vascular smooth muscle contractility, low blood pressure and thrombocytosis. Following intra-arterial mechanical injury, FGF2-deficient vessels undergo a normal hyperplastic response. These results force us to reconsider the function of FGF2 in vascular development and homeostasis in terms of vascular tone control.

Evaluation of the echinocandin antifungal MK-0991 (L-743,872): efficacies in mouse models of disseminated aspergillosis, candidiasis, and cryptococcosis

The in vivo activity of the Merck antifungal echinocandin drug candidate MK-0991 (L-743,872) was evaluated in mouse models of disseminated candidiasis, aspergillosis, and cryptococcosis. The echinocandins are potent inhibitors of 1,3-beta-D-glucan synthase. Two models of disseminated candidiasis were used. In a Candida albicans mouse survival model with both DBA/2N and CD-1 mice, estimates of the 50% effective doses (ED50s) of MK-0991 were 0.04 and 0.10 mg/kg of body weight/dose at 21 days after challenge, respectively. In a C. albicans target organ assay (TOA) with DBA/2N mice, MK-0991 at levels of > or =0.09 mg/kg/dose significantly reduced the numbers of C. albicans CFU/g of kidneys compared to the numbers in the kidneys of control mice from 1 to 28 days after challenge. Even when given as a single intraperitoneal dose either 30 min or 24 h after challenge, MK-0991 was effective and significantly reduced the numbers of C. albicans CFU/g of kidney compared to those in the controls. MK-0991 was >300-fold less active when it was administered orally than when it was administered parenterally. MK-0991 was efficacious in mouse TOAs against other C. albicans strains and Candida species including Candida tropicalis, Candida (Torulopsis) glabrata, Candida lusitaniae, Candida parapsilosis, and Candida krusei. MK-0991 was ineffective against disseminated Cryptococcus neoformans infections. In the model of disseminated aspergillosis in mice, MK-0991 at doses of > or =0.02 mg/kg/dose significantly prolonged the survival of DBA/2N mice, with estimates of the ED50 and ED90 of MK-0991 being 0.03 and 0.12 mg/kg/dose, respectively, at 28 days after challenge. MK-0991 is a potent, parenterally administered therapeutic agent against disseminated candidiasis and aspergillosis that warrants further investigation in human clinical trials.

In vitro preclinical evaluation studies with the echinocandin antifungal MK-0991 (L-743,872)

The echinocandin MK-0991, formerly L-743,872, is a water-soluble lipopeptide that has been demonstrated in preclinical studies to have potent activity against Candida spp., Aspergillus fumigatus, and Pneumocystis carinii. An extensive in vitro biological evaluation of MK-0991 was performed to better define the potential activities of this novel compound. Susceptibility testing with MK-0991 against approximately 200 clinical isolates of Candida, Cryptococcus neoformans, and Aspergillus isolates was conducted to determine MICs and minimum fungicidal concentrations MF(s). The MFC at which 90% of isolates are inhibited for 40 C. albicans clinical isolates was 0.5 microg/ml. Susceptibility testing with panels of antifungal agent-resistant species of Candida and C. neoformans isolates indicated that the MK-0991 MFCs for these isolates are comparable to those obtained for susceptible isolates. Growth kinetic studies of MK-0991 against Candida albicans and Candida tropicalis isolates showed that the compound exhibited fungicidal activity (i.e., a 99% reduction in viability) within 3 to 7 h at concentrations ranging from 0.06 to 1 microg/ml (0.25 to 4 times the MIC). Drug combination studies with MK-0991 plus amphotericin B found that this combination was not antagonistic against C. albicans, C. neoformans, or A. fumigatus in vitro. Studies with 0 to 50% pooled human or mouse serum established that fungal susceptibility to MK-0991 was not significantly influenced by the presence of human or mouse serum. Results from resistance induction studies suggested that the susceptibility of C. albicans was not altered by repeated exposure (40 passages) to MK-0991. Erythrocyte hemolysis studies with MK-0991 with washed and unwashed human or mouse erythrocytes indicated minimal hemolytic potential with this compound. These favorable results of preclinical studies support further studies with MK-0991 with humans.

[A cytogenic study on colorectal carcinoma]

OBJECTIVE

To study the cytogenesis of colorectal carcinoma and to look for colorectal carcinoma related chromosomal fragility sites which could facilitate screening of high risk colorectal carcinoma patients.

METHODS

20 cases of surgically resected colorectal carcinomas and 4 cell lines were analysed cytogenetically.

RESULTS

Most of the tumor cells were heteroploid, the chromosome number was predominately hypodiploid. Karyotypic analysis demonstrated an increase of chromosome 13, and loss of chromosome 17 and chromosome 1 appeared frequently. The most frequently found structural abnormalities in colorectal carcinoma were breakpoint 1q21 and 1p13. Highly non-random cancer chromosome breakpoints and fragile sites were compared with the oncogene locus and found that their locus or neighboring locus was 1q21.

CONCLUSION

The results suggest that breakpoint 1q21 may be related to tumorgenesis and may be useful in screening and preventing colorectal carcinoma.

Melanoma cell adhesion to injured arterioles: mechanisms of stabilized tethering

An isolated perfused vessel model was used to examine the mechanisms underlying the adhesive interactions between circulating tumor cells and subendothelial matrix in denuded arterioles. Arterioles ranging from 70 to 100 microm in diameter were isolated from rat mesentery, transferred to an isolated vessel chamber, cannulated on both ends with glass micropipettes, and perfused with media containing 10(6) hamster melanoma (RPMI 1856) cells/ml. In a second group of arterioles, the endothelium was denuded by running 2 ml of air through the vessel lumen. Since the tumor cells did not adhere to the vessel wall when perfused at physiologically relevant shear rates, perfusate flow was stopped and the tumor cells were allowed to settle onto the vessel wall for 20 min. After counting the number of tumor cells that settled onto the arteriolar wall, perfusate flow was re-initiated and unattached cells were washed away. The number of cells remaining adherent were counted and the percentage of adherent cells (relative to the total number of cells that settled on to the vessel wall during the period of no-flow) were calculated and compared among different groups. We observed that tumor cells are much more adhesive to denuded arterioles than to intact arterioles. To determine the mechanisms responsible for the adhesive interactions that become established and stabilized during the period of flow reduction, denuded arterioles were treated with fibronectin antiserum or Arg-Gly-Asp (RGD) peptides. Both treatments significantly reduced tumor cell adhesion to denuded arterioles. In subsequent studies, melanoma cells were treated with a transglutaminase inhibitor, monodansylcadaverine (MDC), which reduced the ability of adherent tumor cells to withstand the anti-adhesive effects of a subsequent increase in perfusate flow rate after the period of no-flow. Our data suggest that tumor cells adhere to fibronectin in the subendothelial matrix in denuded arterioles by an RGD-dependent mechanism. Moreover, our observations are consistent with the concept that a transglutaminase-catalysed reaction acts to stabilize the adhesive interactions between subendothelial matrix components and melanoma cells during the period of flow stasis such that the cells are able to withstand subsequent substantial increases in wall shear rate and remain adherent.

[The changes of fibrinolysis in plasma and wounds in rats inflicted with deep partial thickness burns]

We observed the changes in wound histopathology and fibrinolysis of rats with deep partial thickness burns during 10 days after scalding in order to study the relations of early progressive damage of deep partial thickness burn wound and the healing of the wound to fibrinolysis. Using Masson's trichrome stain of collagen, we demonstrated that partial thickness burn wound progressively deteriorated within 72 hours postburn, and epidermal cells on wound edge proliferated, creeping between necrotic and residual collagen by 10th day postburn. The results of assays of fibrinolytic parameters in plasma and 24 hour exudate from wound showed that fibrinolysis activated at 2 hour postburn but had been suppressed by 24 hour postburn till last day (10 day postburn) of the observation. The analysis of dynamic changes and relations in fibrinolytic parameters revealed that the suppressive factors of fibrinolysis might be enhanced activities of PAI, alpha 2-antiplasmin and antithrombin II after injury. Results suggested that suppression of fibrinolysis might protect fibrin deposited in the wound from lysis and play an important role in early progressive deterioration of deep partial thickness burn and regulation of its healing.

Immobilized IDA-type Cu2+-chelating membrane affinity chromatography for purification of bovine liver catalase

Cu2+-chelating membrane medium based on iminodiacetate-substituted modified short cotton cellulose was examined to purify bovine liver catalase (BLC) by affinity chromatography. The buffer pH notably affect BLC binding to the Cu2+-chelating membrane adsorbent. The results showed that under the chromatographic conditions chosen, 67.7% recovery of BLC attained with an overall 4.7-fold increase in specific activity in a single step. After purification of BLC, the chelating membrane adsorbent can easily be regenerated by imidazole or EDTA buffer. Different results were obtained by the two regeneration methods: the later is more effective than the former in reviving the purification characters of the chelating membrane adsorbent.

Up-regulation of cytokine mRNA, adhesion molecule proteins, and MHC class II proteins in salivary glands of TGF-beta1 knockout mice: MHC class II is a factor in the pathogenesis of TGF-beta1 knockout mice

Mice homozygous for a disrupted TGF-beta1 allele develop multiple lymphoproliferative disorders similar to those seen in the pseudolymphoma of Sjögren's syndrome. At 2 wk of age, these TGF-beta1 mutant mice begin to develop wasting syndrome and die at around 4 to 5 wk of age. We studied salivary glands from symptomatic mutant mice >14 days of age. Reverse transcriptase-PCR analysis showed up-regulation of proinflammatory cytokine genes such as IL-1alpha, IL-1beta, IL-2, IL-4, IL-6, IL-10, and IFN-gamma in these mutant mice. Enhanced expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule (VCAM-1), and MHC class II as well as CD4-positive T lymphocyte infiltration was detected by immunostaining. To elucidate the role of MHC class II, salivary glands from TGF-beta1/MHC class II double knockout mice were used to investigate the expression of adhesion molecules and MHC class II. In spite of the existence of basal intercellular adhesion molecule-1 expression on vessels, there was neither MHC class II expression, enhanced vascular cell adhesion molecule-1 expression, nor lymphocytic infiltration in the salivary glands. These results suggest that MHC class II plays a significant role in the pathogenesis of TGF-beta1 mutant mice. Although the mechanism that initiates multiple inflammatory diseases in these mice remains unclear, the context reported here would provide insight into the immunopathology of Sjögren's syndrome.

Up-regulation of cytokine mRNA, adhesion molecule proteins, and MHC class II proteins in salivary glands of TGF-beta1 knockout mice: MHC class II is a factor in the pathogenesis of TGF-beta1 knockout mice

Mice homozygous for a disrupted TGF-beta1 allele develop multiple lymphoproliferative disorders similar to those seen in the pseudolymphoma of Sjögren's syndrome. At 2 wk of age, these TGF-beta1 mutant mice begin to develop wasting syndrome and die at around 4 to 5 wk of age. We studied salivary glands from symptomatic mutant mice >14 days of age. Reverse transcriptase-PCR analysis showed up-regulation of proinflammatory cytokine genes such as IL-1alpha, IL-1beta, IL-2, IL-4, IL-6, IL-10, and IFN-gamma in these mutant mice. Enhanced expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule (VCAM-1), and MHC class II as well as CD4-positive T lymphocyte infiltration was detected by immunostaining. To elucidate the role of MHC class II, salivary glands from TGF-beta1/MHC class II double knockout mice were used to investigate the expression of adhesion molecules and MHC class II. In spite of the existence of basal intercellular adhesion molecule-1 expression on vessels, there was neither MHC class II expression, enhanced vascular cell adhesion molecule-1 expression, nor lymphocytic infiltration in the salivary glands. These results suggest that MHC class II plays a significant role in the pathogenesis of TGF-beta1 mutant mice. Although the mechanism that initiates multiple inflammatory diseases in these mice remains unclear, the context reported here would provide insight into the immunopathology of Sjögren's syndrome.

[Treatment of congenital glaucoma with trabeculotomy]

OBJECTIVE

To investigate the method of localization of Schlemm's canal during trabeculotomy to evaluate the successful rate of trabeculotomy.

METHOD

The author treated 38 cases (46 eyes) of congenital glaucoma with trabeculotomy. Harms trabeculotomy knife was introduced into the Schlemm's canal through the cutting end of an external collecting channel. The follow-up period was over 6 months in 37 eyes.

RESULTS

The intraocular pressure, C/D ratio were significantly improved after surgery compared to the preoperative ones (P < 0.05). But no significant differences were found in the corneal diameter, the depth of the anterior chamber, the length of ocular axis before and after surgery (P > 0.05). The intraocular pressure of 27 eyes (73.0%) was less than or equal to 2.8 kPa (1 kPa = 7.5 mmHg), showing good control of glaucoma.

CONCLUSION

During trabeculotomy, the trabeculotomy knife introduced in to the Schlemm's canal through an external collecting channel is a better and accurate method of localization of Schlemm's canal. The method is relatively simple, reliable and has certain value in clinical application.

Evaluation of experimental therapeutics in a new mouse model of Helicobacter felis utilizing 16S rRNA polymerase chain reaction for detection

BACKGROUND

A new mouse model of Helicobacter felis infection, which mimics the human infection observed with H. pylori, has recently been developed utilizing polymerase chain reaction (PCR) based on the 16S rRNA gene sequence for detection of infection.

METHODS

We tested several therapeutic regimens in this model, including some currently utilized in the clinic and some shown ineffective in the clinic.

RESULTS

The therapeutic results obtained by PCR with this model are consistent with results observed in the published human H. pylori clinical trials and also with results obtained in another H. felis mouse model utilizing culture and histology.

CONCLUSIONS

These results support further use of this new model in screening for new therapeutic regimens for the management of Helicobacter disease.

Fas and Fas ligand expression in the salivary glands of patients with primary Sjögren's syndrome

OBJECTIVE

To assess the role of Fas-mediated apoptosis in the salivary glands of patients with primary Sjögren's syndrome (SS).

METHODS

Expression of Fas, Fas ligand (FasL), and bcl-2 in salivary gland biopsy material was detected in situ by immunohistochemical staining and reverse transcriptase-polymerase chain reaction. DNA fragmentation in apoptotic cells was assessed by the enzymatic incorporation of labeled nucleotides (digoxigenin-dUTP).

RESULTS

The acinar epithelial cells in SS were Fas+ and FasL+, and these cells died by apoptosis. The majority of infiltrating lymphocytes in SS were Fas+ and bcl-2+, while few lymphocytes expressed FasL. In situ detection of apoptosis showed minimal cell death of lymphocytes, particularly in dense periductal foci. Lymphocytic cell death was significantly lower (P < 0.0001) in these foci compared with that in the interstitium.

CONCLUSION

Infiltrating lymphocytes in the focal lesions of the salivary glands of patients with SS are blocked in their ability to commit to apoptosis, even though they may express Fas. The presence of bcl-2 in these cells may explain their inability to undergo apoptosis. The acinar epithelial cells, in contrast, may undergo Fas-mediated apoptosis. These results suggest that the Fas death pathway may be an important mechanism leading to the glandular destruction found in SS.

[Design and application of vacuum manifold for solid phase extraction]

Solid phase extraction (SPE) is now a common method for sample pretreatment. SPE vacuum manifold is a key instrument when SPE is used for sample pretreatment. It was developed by National Chromatographic R. & A. Center. Being connected with a vacuum pump, it can deal with 12 samples simultaneously. The manifold has a unique rotatable cover and can be conveniently rotated when switching between any two steps of SPE. An application of this SPE vacuum manifold in measuring bile acids in human serum was given.

Lymphocyte apoptosis and apoptosis-associated gene expression in Sjögren's syndrome

OBJECTIVE

To study the mechanism and regulation of apoptosis in peripheral blood T and B lymphocytes from patients with Sjögren's syndrome (SS).

METHODS

The mode of in vitro lymphocyte death in the peripheral blood of patients with SS was determined by fluorescence microscopic analysis, terminal deoxynucleotidyl transferase assay, and DNA fragmentation analysis. Apoptotic cell death of T and B cells was determined at 48 hours of culture by fluorescence-activated cell sorter analysis of propidium iodidestained cells. Messenger RNA (mRNA) expression of bcl-2, bcl-x, bax, and c-myc in T and B cells was determined by enzyme-linked immunosorbent assay-polymerase chain reaction (ELISA-PCR). Expression of bcl-xL and bcl-xS was determined by Southern blot analysis of PCR products. Gene expression was calculated as the ratio of each gene message to the message of the GAPDH gene. Bcl-2 protein levels in SS T cells were determined by ELISA.

RESULTS

SS T cells showed increased in vitro apoptosis compared with normal T cells (mean +/- SD 12.3 +/- 4.5% versus 7.3 +/- 2.0%; P < 0.01). Freshly isolated SS T cells showed increased expression of bcl-2 mRNA compared with normal controls (mean +/- SD 1.50 +/- 0.65 versus 0.88 +/- 0.23; P < 0.05). There was no significant difference in levels of bax or c-myc mRNA in T cells and B cells between SS patients and normal controls. When SS T lymphocytes were cultured in vitro for 72 hours, Bcl-2 protein levels decreased with time.

CONCLUSION

SS T cells showed accelerated apoptosis in vitro. Freshly isolated SS T cells had increased expression of bcl-2. An increase in death-promoter signals and decrease in death-suppressor signals in vitro may have been responsible, in part, for the apoptosis in SS T lymphocytes.

Autoimmunity associated with TGF-beta1-deficiency in mice is dependent on MHC class II antigen expression

The progressive inflammatory process found in transforming growth factor beta1 (TGF-beta1)-deficient mice is associated with several manifestations of autoimmunity, including circulating antibodies to nuclear antigens, immune complex deposition, and increased expression of both class I and class II major histocompatibility complex (MHC) antigens. The contribution of MHC class II antigens to the genesis of this phenotype has been determined by crossing the TGF-beta1-null [TGF-beta1(-/-)] genotype into the MHC class II-deficient [MHC-II(-/-)] background. Mice homozygous for both the TGF-beta1 null allele and the class II null allele [TGF-beta1(-/-);MHC-II(-/-)] are without evidence of inflammatory infiltrates, circulating autoantibodies, or glomerular immune complex deposits. Instead, these animals exhibit extensive extramedullary hematopoiesis with progressive splenomegaly and adenopathy, surviving only slightly longer than TGF-beta1(-/-);MHC-II(+/+) mice. The role of CD4+ T cells, which are also absent in MHC class II-deficient mice, is directly demonstrated through the administration of anti-CD4 monoclonal antibodies in class II-positive, TGF-beta1(-/-) mice. The observed reduction in inflammation and improved survival emphasize the significance of CD4+ cells in the pathogenesis of the autoimmune process and suggest that the additional absence of class II antigens in TGF-beta1(-/-);MHC-II(-/-) mice may contribute to their extreme myeloid metaplasia. Thus, MHC class II antigens are essential for the expression of autoimmunity in TGF-beta1-deficient mice, and normally may cooperate with TGF-beta1 to regulate hematopoiesis.

[Effects of different processed products of radix Angelica sinensis on clearing out oxygen free radicals and anti-lipid peroxidation]

Different processed products of Radix Angelica Sinensis could clear out superoxide radical (O2.-) generated through hypoxanthinexanthine oxidase system and hydroxyl radical (.OH) generated through Fenton action, and inhibit lipid peroxidation of supernatant hepati homogenate in mice induced by free radical generation system. There exist significant differences among the different processed products.

Nitric oxide reduces tumor cell adhesion to isolated rat postcapillary venules

Adhesion of circulating tumor cells to microvascular endothelium plays an important role in tumor metastasis to distant organs. The purpose of this study was to determine whether nitric oxide (NO) would attenuate tumor cell adhesion (TCA) to naive or lipopolysaccharide (LPS)-treated postcapillary venules. A melanoma cell line, RPMI 1846, was shown to be much more adhesive to postcapillary venules isolated from rat mesentery than to corresponding precapillary arterioles. Although venules exposed to LPS for 4 h demonstrated an increased adhesivity for the melanoma cells, TCA to LPS-treated arterioles was not altered. Isolated venules exposed to DETA/NO (1 mM), an NO donor, for 30 min prior to tumor cell perfusion prevented the increment in adhesion induced by LPS and attenuated TCA to naive postcapillary venules. While L-arginine (100 microM), an NO precursor, failed to decrease TCA to naive postcapillary venules, this treatment abolished LPS-stimulated TCA to postcapillary venules. The effect of L-arginine was reversed by administration of N(omega)-nitro-L-arginine methyl ester (L-NAME, 100 microM), an NO synthase (NOS) inhibitor. These observations indicate that both exogenous and endogenous NO modulate TCA to postcapillary venules. To assess the role of NO-induced activation of cGMP in the reduction in TCA produced by DETA/NO, two additional series of experiments were conducted. In the first series, LY-83583 (10 microM), a guanylyl cyclase inhibitor, was shown to completely reverse the effect of DETA/NO on TCA to both naive and LPS-activated postcapillary venules. On the other hand, administration of 8-bromoguanosine 3',5'-cyclic monophosphate (8-B-cGMP) (1 mM), a cell permeant cGMP analog, mimicked the effect of DETA/NO and reduced TCA to LPS-stimulated postcapillary venules. These data suggest that (a) tumor cells are more likely to adhere to postcapillary venules than to corresponding precapillary arterioles, (b) LPS enhances TCA to postcapillary venules, (c) both exogenously applied (DETA/NO) and endogenously generated (L-arginine) NO attenuate the enhanced adhesion induced by LPS, but only DETA/NO reduced TCA to naive postcapillary venules, and (d) the NO-induced reduction in TCA to LPS-activated postcapillary venules occurs by a cGMP-dependent mechanism.

[Selection of technology for processing steamed Garcinia hunburyi with high pressure]

The technology for processing steamed Garcinia hunburyi with high pressure was synthetically selected by using orthogonal experiment design, based on the indexes of anti-inflammatory, bacteriocidal, anti-tumour effects and gambagic acid content. The result shows that the best way is to steam for 0.5 h at 126 degrees C.

Tumor necrosis factor mediates apoptosis via Ca++/Mg++ dependent endonuclease with protein kinase C as a possible mechanism for cytokine resistance in human renal carcinoma cells

PURPOSE

Because renal cell cancers have been found to be resistant to numerous chemotherapeutic agents, other agents including tumor necrosis factor are now being considered for clinical use. In this study, we used 2 renal cancer cell lines. SK-RC-42 and SK-RC-49, and determined the cytotoxic effects of tumor necrosis factor (TNF) and the possible mechanism of TNF resistance.

MATERIALS AND METHODS

Cytotoxic assays, comparative reverse transcriptase-polymerase chain reaction (RT-PCR) and nuclease digestion analyses were used.

RESULTS

Cytotoxic assays with SK-RC-42 demonstrated that TNF at 50 ng./ml. for 24 hours resulted in 19% cytotoxicity of the cells. Similar assay with SK-RC-49 only demonstrated less than 4% cytotoxicity. Based on these results, we defined our TNF-sensitive cells as SK-RC-42 and SK-RC-49 as our TNF-resistant cells. To determine whether protein kinase C (PKC), which is involved in the signal transduction pathway of a cell, could regulate endogenous basal TNF mRNA levels, comparative PCR analyses for TNF expression were used. The PCR results demonstrated that the TNF-resistant cell, SK-RC-49, had a higher basal expression of TNF mRNA than the TNF-sensitive cell SK-RC-42. With PMA, a PKC activator, for various time points, both cell lines demonstrated an induction of endogenous TNF mRNA. To further confirm our findings that PKC may regulate endogenous TNF expression, a PKC inhibitor, staurosporine, was used. When the cells were treated with staurosporine prior to PMA stimulation, no increase in TNF mRNA expression was seen. To determine whether PKC is involved in providing resistance against TNF, we incubated the SK-RC-42 and SK-RC-49 cells with staurosporine at 100 nM. and TNF at 50 ng./ml. for 24 hours. After factoring out the cytotoxicity of staurosporine, the TNF-mediated cytotoxicity increased to 39.3% and 28.7% for the SK-RC-42 and SK-RC-49 cells, respectively. Furthermore, by using a nuclease digestion assay, we demonstrated that TNF activated a Ca++/Mg++ dependent endonuclease responsible for programmed cell death or apoptosis.

CONCLUSIONS

Our data suggest that protein kinase C may play a role in protecting renal cancer cells from undergoing cytokine-mediated apoptosis.

Production of premature delivery in pregnant rhesus monkeys by androstenedione infusion

The endocrine mechanism involved in term and preterm delivery in primates, including pregnant women, are poorly understood. In the term monkey, fetal plasma androgen concentration rises to two hundred times the maternal concentration which remains unchanged. Placental conversion of androgen to estrogen results in increased maternal plasma estrogen concentration at term in both pregnant nonhuman primates and women. In the present study, continuous infusion of androstenedione to 0.8 gestation monkeys resulted in the premature occurrence of labor-type myometrial activity and increases in maternal plasma estrogen, oxytocin and amnion fibronectin concentrations similar to those measured at normal-term labor. Androstenedione induction of these normal-term biochemical and endocrine changes accompanied by fetal membrane rupture, cervical dilatation and live delivery provides a rich opportunity to study the molecular and physiological mechanisms of both term and preterm labor in primates.

[Acute toxicity and anti-inflammatory effect of processed products of gamboge]

The acute toxicity and anti-inflammatory effect of processed and raw Gamboge were compared. The results showed that the acute toxicity of processed Gamboge was less than that of the raw one, while both had significant anti-inflammatory effect alike. Among the differently processed products, those boiled with lotus leaf juice and steamed by high pressure were better.

[The effect of salmeterol on the activity of neutrophil chemotactic factor in patients with asthma]

OBJECTIVE

The activity of neutrophil chemotactic factor (NCF) in serum of 40 patients with asthma on their acute attacks was measured with membrane filter method.

METHODS

Of the 26 patients, 13 were administed salmeterol 50 micrograms bid by inhaler and another 13 took procaterol 50 micrograms bid orally for four weeks.

RESULTS

It was found that in patients with asthma NCF was 82 +/- 17 cell/10 HP, which was significantly higher than that in normal subjects (33 +/- 5 cell/10 HP, P < 0.01). After treatment with salmeterol the decrease in NCF activity was 26 cell/10 HP (P < 0.01), while the decrease in another group treated with procaterol was 8 cell/10 HP (P > 0.05). The difference between the two treated groups was significant (P < 0.01). In salmeterol treated group the decrease in NCF activity was more remarkable than the improvement in lung function.

CONCLUSIONS

It was considered that the result may be related to the anti-inflammatory effect of salmeterol.

Ha-ras oncogene expression abrogates a pH dependent endonuclease activity of apoptosis in normal rat kidney cells

To investigate the role of oncogene expression in the resistance to tumor necrosis factor-alpha (TNF), we transfected the mutated T24-Ha-ras oncogene into the murine kidney cell line NRK and an alternative murine cell line C127 cells. The resulting transfectants, NRK-Ha and HC127, were assayed for TNF mediated cytotoxicity. Cellular cytotoxicity of 45% over 48 h occurred with the NRK cells. However, ras transfectant NRK-Ha cells demonstrated 0% cytotoxicity over the same period. Both C127 cells and the ras transfectant HC127 demonstrated 40% and 25% cytotoxicity, respectively, over 48 h when incubated with TNF. Furthermore, DNA isolated from NRK, C127, HC127, but not NRK-Ha cells revealed the presence of DNA fragmentation 'ladders' indicative of successful apoptosis when the cells were incubated with TNF. To determine the possible mechanism in which the ras oncogene may have protected the NRK-Ha cells from TNF mediated cytotoxicity and apoptosis, total nuclear endonucleases from the NRK cells and the ras transfectant NRK-Ha cells were isolated. We determined that the endonuclease activity in the NRK and the ras transfectant NRK-Ha cells was a pH dependent endonuclease. Significant degradation of the target DNA was observed only in pH 4-6 buffers containing the endonuclease. Furthermore, preliminary intracellular pH analysis suggested that while the NRK cells have an intracellular pH of 6.0, the ras transfectant NRK-Ha cells have an intracellular pH of 7.2 and may have abrogated its pH dependent endonuclease. Both the C127 cells and the ras transfectant HC127 cells did not express a pH dependent endonuclease but rather a Ca2+/Mg2+ dependent endonuclease. Furthermore, preliminary intracellular pH analysis suggested that both the C127 and HC127 cells have the same intracellular pH. Our results indicate that in normal rat kidney cells, ras oncogene transfection may cause a disruption in the endonuclease activation involved in apoptosis.

A sensitive and specific PCR method to detect Helicobacter felis in a conventional mouse model

Although many detection methods have been used to determine Helicobacter colonization in small animal models, the sensitivity and specificity of these detection methods are limited. To improve the Helicobacter felis conventional mouse model for accurate evaluation of therapeutic regimens, we developed a PCR for detection of, and a competitive PCR for quantitation of, H. felis in viral antibody-free (VAF) mice. The PCR was based on the H. felis 16S rRNA gene. An internal control DNA was used for competitive quantitation of the PCR. VAF conventional Swiss-Webster mice were infected with an H. felis culture by oral gavage. At various times after H. felis challenge and therapy, stomach mucosa was collected and evaluated by PCR. PCR detected approximately 50 to 100 H. felis cells per mouse stomach and showed no cross-reaction with other bacteria commonly found in mouse stomachs. Colonization of H. felis in the mouse stomach was confirmed by culture isolation from germfree mice and histological examination of VAF mice. Response to therapy in this H. felis model correlated well with results seen in human clinical trials with H. pylori. A model utilizing PCR detection which may be useful for discovering new antibiotics and/or vaccines against Helicobacter ulcer disease has been developed.

PCR detection of colonization by Helicobacter pylori in conventional, euthymic mice based on the 16S ribosomal gene sequence

Many animal models of Helicobacter infection have been described, including infection in rhesus monkeys, ferrets, gnotobiotic piglets, and mice. These animal models utilize a combination of detection methods, including culture, urease testing, and histopathology, all of which may be unreliable, insensitive, or labor-intensive. Development of new animal models of Helicobacter pylori requires new methods of detection with increased sensitivity and specificity. We have developed sensitive and specific PCR primers based on the 16S ribosomal gene sequence of H. pylori. The primers detected single-copy 16S DNA representing 0.2 cell of pure H. pylori (2 cells in the presence of mouse stomach mucosal DNA) and did not cross-react with closely related bacteria. We were able to detect colonization by H. pylori in conventional, euthymic, outbred mice up to 4 weeks postinoculation with a high percentage of isolates tested. One isolate of H. pylori was detected by PCR in 100% of the mice at 6 months and 60% of the mice 1 year after inoculation. Approximately 10(3) to 10(4) H. pylori cells per stomach were detected by utilizing this PCR methodology semiquantitatively. These primers and PCR methodology have facilitated detection of H. pylori colonization in conventional, euthymic mice, colonization which may not have been detectable by other methods.

Opposing actions of transforming growth factor-beta and glucocorticoids in the regulation of fibronectin expression in the human placenta

Alterations in the expression of extracellular matrix (ECM) proteins in the placenta and fetal membranes have been linked to parturition whether occurring before or at term. In the present study, we examined the individual and combined effects of transforming growth factor (TGF)-beta and dexamethasone (DEX) on the expression of oncofetal fibronectin (onfFN), i.e. a major ECM protein synthesized by placenta, in cytotrophoblasts isolated from human term placentas to establish a model system from which to evaluate the actions of positive and negative regulators of ECM protein expression in the human placenta. Cytotrophoblasts were maintained for 21=62 h in medium supplemented with 4% charcoal-stripped calf serum in the presence or absence of TGF-beta (2 ng/mL) and DEX (10(-7) mol/L). Levels of onfFN in culture media were determined by immunoassay. TGF-beta treatment alone induced approximately a 150% increase in media levels of onfFN after 21 and 45 h of culture when compared with control, whereas DEX treatment alone reduced levels of onfFN to 15% of control levels. Media levels of onfFN in cells treated with both TGF-beta and DEX were 40-90% of control levels. Similarly, treatment of cells with TGF-beta alone promoted a 100-250% increase in rates of FN synthesis and levels of FN messenger ribonucleic acid, whereas DEX treatment alone reduced these indices of FN expression to approximately 10% of control levels. In cells treated with TGF-beta and DEX, levels of ECM protein synthesis and FN messenger ribonucleic acid were between 30 and 100% of control values. Similar patterns of regulation of FN expression by TGF-beta and DEX were observed when experiments were carried out in serum-free medium. Our results suggest that during pregnancy, TGF-beta and glucocorticoids may be important opposing physiological regulators of placental ECM protein expression.

VEGF gene expression is upregulated in electrically stimulated rat skeletal muscle

Vascular endothelial growth factor (VEGF; also called vascular permeability factor) is a secreted mitogen with distinct target cell specificity for vascular endothelial cells. Hypoxia upregulates VEGF expression, making it a likely mediator of the angiogenesis that occurs in poorly perfused tissues. The purpose of this study was to determine whether VEGF gene expression is upregulated in chronically stimulated skeletal muscles, where hypoxia is thought to trigger the growth of blood vessels. The right anterior tibialis and extensor digitorum longus muscles of 12 rats were stimulated electrically (10 Hz, 300 microseconds pulses) for up to 21 days by way of the peroneal motor nerve. The contralateral muscles served as control. Northern analysis showed that VEGF mRNA levels increased by approximately sixfold after 4 days of stimulation and then decreased gradually over the next several days. VEGF mRNA levels were still elevated by two- to threefold after 21 days of stimulation. Higher VEGF mRNA levels in the early stages of muscle stimulation and gradually decreasing levels in later stages are consistent with a metabolic hypothesis in which tissue oxygenation controls VEGF expression. These studies support the hypothesis that VEGF has a physiological role in promoting angiogenesis in stimulated skeletal muscle.

T-lymphocyte subsets in acute illness

OBJECTIVES

To determine the range of T-lymphocyte subsets (CD4, CD8, and CD4/CD8 ratios) in acutely ill, hospitalized patients and to determine whether these concentrations correlate with illness severity, survival rate, or immunodepression.

DESIGN

Cross-sectional study, comparing Acute Physiology and Chronic Health Evaluation II (APACHE II) scores and the calculated, disease-specific, predicted mortality rate with T-lymphocyte subsets.

SETTING

Urban county hospital intensive care unit (ICU), serving as the designated trauma center.

PATIENTS

One hundred two consecutively admitted ICU patients (72 medical and 30 surgical).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patient clinical data, APACHE II scores, and their associated predicted mortality rate were recorded. Blinded human immunodeficiency virus (HIV) and lymphocyte testing was performed on samples from all patients on ICU admission. Despite only three (2.9%) of 102 patients testing positive for HIV antibodies, 41% (42/102) of patients had CD4 concentrations of < 400 cells/microL, and 29% (29/102) had CD4 concentrations of < 300 cells/microL. Mean CD8 concentrations were even lower, compared with normal laboratory values, resulting in a slight increase in CD4/CD8 ratios, although 16% (16/102) of patients had a CD4/CD8 ratio of < 1. CD4 counts were linearly related to total lymphocyte concentrations (Pearson correlation coefficient = 0.948), but no relationship was found between total lymphocyte or lymphocyte subset counts and APACHE II score, predicted mortality rate, or survival rate.

CONCLUSIONS

Acute illness alone, in the absence of HIV infection, can be associated with profound decreases of T-lymphocyte populations. This problem is unpredictable and does not correlate with severity of illness, predicted mortality rate, or actual mortality rate. No conclusions regarding HIV serostatus or survival can be made based on single measurements of T-cell concentrations in acutely ill hospitalized patients.

In vivo evaluation of three acid-stable azalide compounds, L-701,677, L-708,299 and L-708,365 compared to erythromycin, azithromycin and clarithromycin

L-701,677, L-708,299 and L-708,365 are novel azalide derivatives of erythromycin that exhibit improved acid stability over erythromycin, azithromycin and clarithromycin. The half-life in aqueous solution at pH = 2.1 of these compounds ranged from 0.3 hour for erythromycin to 16.2 hours for L-708,299. The rank order of half-life in acid solution from most to least stable was L-708,299 > L-701,677 > L-708,365 > azithromycin = clarithromycin > erythromycin. In a disseminated Streptococcus pyogenes mouse infection model, azithromycin and L-708,365 were slightly more efficacious than clarithromycin, L-701,677 and L-708,299; all 5 compounds being more active than erythromycin. In a Klebsiella pneumoniae pulmonary challenge mouse model, azithromycin, L-701,677, L-708,299 and L-708,365 were all equal in efficacy and at least four-fold more active than clarithromycin and erythromycin. Clarithromycin, L-708,365 and interestingly erythromycin, showed greater bacterial clearance than azithromycin, L-701,677 and L-708,299 in a localized infection model that measured clearance of Staphylococcus aureus from mouse thigh tissues. Our results indicate that L-701,677, L-708,299 and L-708,365 exhibit improved acid stability and were at least equally efficacious as presently marketed macrolide/azalide antibiotics.

SLE-like autoantibodies and Sjögren's syndrome-like lymphoproliferation in TGF-beta knockout mice

Mice bearing the TGF-beta 1 null mutation (-/-) develop lymphoid infiltrates in the heart, lungs, salivary glands, and other organs similar to those seen in the pseudolymphoma of Sjögren's Syndrome. We studied sera from -/- mice and found elevated Ab levels to dsDNA, ssDNA, and Sm ribonucleoprotein. No Abs to SSA/Ro or SSB/La and no IgM rheumatoid factor were found. Serum autoantibodies were predominately IgG and were specific as shown by ELISA inhibition studies. Antinuclear Ab patterns on Western blots varied from one mouse to the next, indicating a random process responsible for the diversity. Wild-type and heterozygote mice had no autoantibodies. Ig glomerular deposits were found in -/- mice, indicating that these autoantibodies may be pathogenic. Treatment of -/- mice with dexamethasone or TGF-beta 1 failed to suppress autoantibody production. These mice represent an overlap combining the autoimmune serology of SLE with the tissue infiltrates of SS. Our results support the concept that TGF-beta 1 is an important naturally occurring immunosuppressive cytokine whose absence can lead to a systemic autoimmune disease.

SLE-like autoantibodies and Sjögren's syndrome-like lymphoproliferation in TGF-beta knockout mice

Mice bearing the TGF-beta 1 null mutation (-/-) develop lymphoid infiltrates in the heart, lungs, salivary glands, and other organs similar to those seen in the pseudolymphoma of Sjögren's Syndrome. We studied sera from -/- mice and found elevated Ab levels to dsDNA, ssDNA, and Sm ribonucleoprotein. No Abs to SSA/Ro or SSB/La and no IgM rheumatoid factor were found. Serum autoantibodies were predominately IgG and were specific as shown by ELISA inhibition studies. Antinuclear Ab patterns on Western blots varied from one mouse to the next, indicating a random process responsible for the diversity. Wild-type and heterozygote mice had no autoantibodies. Ig glomerular deposits were found in -/- mice, indicating that these autoantibodies may be pathogenic. Treatment of -/- mice with dexamethasone or TGF-beta 1 failed to suppress autoantibody production. These mice represent an overlap combining the autoimmune serology of SLE with the tissue infiltrates of SS. Our results support the concept that TGF-beta 1 is an important naturally occurring immunosuppressive cytokine whose absence can lead to a systemic autoimmune disease.

Reduction of extracellular matrix protein expression in human amnion epithelial cells by glucocorticoids: a potential role in preterm rupture of the fetal membranes

Low levels of expression of extracellular matrix (ECM) proteins in chorioamniotic membranes is a characteristic of prematurely ruptured membranes, a condition associated with 40% of preterm deliveries. In light of the rise in levels of glucocorticoids (GC) in amniotic fluid associated with preterm labor, in the present study we examined the effects of GC on the expression of major ECM proteins in cultures of amnion epithelial cells recovered after digestion of human term amnions. Amnion cells were maintained with and without 10(-7) mol/L dexamethasone (DEX), and levels of the ECM protein fibronectin (FN) were determined by enzyme-linked immunosorbent assay. DEX treatment reduced FN expression in amnion epithelial cells to 15-30% of control levels and reduced FN expression in placental cells to 30-50% of control levels. Conversely, DEX treatment weakly stimulated FN expression in chorion cell cultures. DEX treatment did not affect the total level of amnion cell protein, indicating that the effects of DEX in amnion cells did not result from a general reduction in protein synthesis. Cortisol and DEX reduced FN expression in amnion cells, with half-maximal effective concentrations of approximately 60 and 8 nmol/L, respectively. In immunoprecipitation studies, DEX treatment reduced FN and collagen III synthesis to 20% of control levels, suggesting that GC may coordinately reduce the synthesis of major ECM proteins in amnion cells. Similarly, DEX treatment reduced the levels of FN messenger ribonucleic acids in amnion cells to approximately 15% of control levels. DEX treatment also promoted a marked reduction in FN expression in amnion cells cultured in serum-free medium to 10-50% of control levels. Our results indicate that GC negatively regulate ECM protein expression in amnion epithelial cells, suggesting a potential role in the genesis of altered fetal membrane ECM protein expression associated with prematurely ruptured membranes.

LAK cell mediated apoptosis of human bladder cancer cells involves a pH-dependent endonuclease system in the cancer cell: possible mechanism of BCG therapy

Intravesical bacillus Calmette-Guerin (BCG) is an effective treatment for superficial bladder cancer. However, its mechanism has been only partially elucidated. We studied whether LAK cell killing of human bladder cancer cells occurs via apoptosis (programmed cell death) or necrosis. Fluorescent dye labeled T24 cells were observed to undergo morphologic changes associated with apoptosis in the presence of LAK cells when analyzed under a fluorescence microscope. Furthermore, analysis of the DNA isolated from the cytotoxic assay confirmed that the LAK cell induced death of the T24 cells occurred via apoptosis. By pretreating the LAK cells with antifibronectin antibodies, we were able to significantly inhibit the LAK cell killing of the T24 cells. The percentage of cytotoxicity was reduced from 50% to 13% (p = 0.001), and the apoptotic pattern seen on agarose gel electrophoresis was significantly diminished. There was no significant change in the viability of the LAK cells following treatment with the antibodies. Endonuclease isolation from human bladder cancer T24 cells demonstrated that these cells express a pH-dependent and not a Ca++/Mg++ dependent endonuclease. Significant degradation of a target DNA was observed only in pH 4 to pH 5.6 buffers containing endonuclease from T24 cells and not in pH 6 to pH 8 buffers containing endonuclease from T24 cells. The presence or absence of Ca++/Mg++ in the various pH buffers did not alter the endonuclease activity. Finally, we demonstrated that death of T24 cells can be induced by altering the intracellular pH of the cells to 5.6 or lower with the proton ionophore nigericin. We conclude that LAK cells induce T24 cells to undergo apoptosis and that this process involves the fibronectin molecule present on the LAK cell membrane. Furthermore, the cleavage postulate that, in vivo, LAK cells activated by IL-2 produced by BCG activated CD4+ cells may induce bladder cancer cells to undergo apoptosis. This may partially explain the mechanism whereby BCG achieves its therapeutic effect.

Evaluation of water-soluble pneumocandin analogs L-733560, L-705589, and L-731373 with mouse models of disseminated aspergillosis, candidiasis, and cryptococcosis

The activities of the water-soluble pneumocandin derivatives L-733560, L-705589, and L-731373 were evaluated in mouse models of disseminated aspergillosis, candidiasis, and cryptococcosis and were compared with those of commercially available antifungal agents. Pneumocandins are inhibitors of 1,3-beta-D-glucan synthesis. In the aspergillosis model, L-733560 and L-705589 significantly prolonged the survival of DBA/2N mice challenged intravenously with Aspergillus fumigatus conidia. L-733560 and L-705589 exhibited efficacies comparable to that of amphotericin B (AMB) with 90% effective doses of 0.48, 0.12, and 0.36 mg/kg of body weight, respectively. Two mouse models of disseminated candidiasis were used to evaluate these compounds. In both models, mice were challenged intravenously with Candida albicans. In a C. albicans survival model with DBA/2N and CD-1 mice, the efficacy of L-733560 was comparable to that of AMB, while L-731373 and L-705589 were somewhat less active. In a previously described C. albicans target organ kidney assay, the pneumocandin analogs and AMB at doses of > or = 0.09 mg/kg were effective in sterilizing kidneys, while fluconazole and ketoconazole were considerably less active and did not sterilize kidneys when they were used at concentrations of < or = 100 mg/kg. Although orally administered L-733560 showed activity in both candidiasis models, its efficacy was reduced compared with that of parenterally administered drug. In a disseminated cryptococcosis mouse model that measures the number of CFU of Cryptococcus neoformans per gram of brain and spleen, L-733560 at 10 mg/kg was ineffective in reducing the counts in organs, while AMB at 0.31 mg/kg sterilized the organs. These results indicate that the pneumocandins may be beneficial as potent parenterally administered therapeutic agents for disseminated aspergillosis and candidiasis.

Clinical analysis of steroid glaucoma

PURPOSE

The authors accumulated 15 cases (26 eyes) of steroid glaucoma due to topical administration of dexamethasone or prednisolone.

METHODS

From 1970 to 1990, 26 eyes in 15 cases were observed (bilateral 11 cases, unilateral 4 cases) including 12 right eyes and 14 left eyes. 10 cases were male and 5 cases female with age ranging from 14 to 52 years averaging 28 years. 25 eyes had the manifestation of chronic open angle glaucoma in the clinical course, and 1 eye simulated an acute glaucoma attack.

RESULTS

All patients had taken antiglaucoma medication before coming to our hospital, but the IOP was over 6.7 kPa in 9 eyes. The C/D ratio was equal to or over 0.6 in 9 cases (16 eyes), and the values were inconsistent between both eyes in 55% of the patients. Treatment for glaucoma was immediate discontinuation of the steroids with antiglaucoma medication if necessary. Three eyes received filtering operations and 2 eyes had the removal of subconjunctival residual steroid. Normal IOP was restored in months up to a year.

CONCLUSION

Dexamethasone or prednisolone were the easiest to induce steroid glaucoma when the patients had long-term use of steroid eyedrops.

comK encodes the competence transcription factor, the key regulatory protein for competence development in Bacillus subtilis

comK is a positive autoregulatory gene occupying a central position in the competence-signal-transduction network. All regulatory routes identified in this network converge at the level of comK expression. The ComK protein is required for the transcriptional induction of comK and the late competence genes, which specify morphogenetic and structural proteins necessary for construction of the DNA-binding and uptake apparatus. In this report we demonstrate that ComK specifically binds to DNA fragments containing promoter and upstream sequences of the genes it affects (comC, comE, comF, comG and comK). Using portions of the region upstream of comC we show that the ComK-binding sequences are essential for the expression of competence. Moreover, we demonstrate that the presence of ComK stimulates the expression of comF-lacZ and comG-lacZ translational fusions in vivo in Escherichia coli. These results indicate that the gene product of comK is identical to the previously inferred competence transcription factor (CTF).

Early clinical experience with a hybrid bioartificial liver

BACKGROUND

Severe liver failure is associated with high mortality. Orthotopic liver transplantation (OLT) is the only effective therapeutic modality; there is a need for a 'bridge' system to support patients until an organ becomes available.

METHODS

A bioartificial liver (BAL) was used to treat 10 patients with severe liver failure. A plasmapheresis system was used to pump patient plasma through a module with porcine hepatocytes. Each treatment lasted 6-7 h.

RESULTS

All patients tolerated the procedure(s) well. Eight patients underwent OLT following BAL treatment(s). There were two late deaths after recovery from liver failure. Five patients with increased intracranial pressure (ICP) and decerebration had ICP normalization, increased cerebral perfusion pressure and full neurologic recovery after OLT. There was improvement in the level of encephalopathy and a significant decrease in serum ammonia after BAL treatment(s).

CONCLUSIONS

BAL treatment is safe and beneficial and can be successfully used as a 'bridge' to transplantation.

The regulation of competence transcription factor synthesis constitutes a critical control point in the regulation of competence in Bacillus subtilis

comK, which encodes the competence transcription factor, is itself transcriptionally activated at the transition from exponential growth to stationary phase in Bacillus subtilis. MecA, a negative regulator of competence, also inhibits comK transcription when overexpressed, and a mecA null mutation results in comK overexpression. Although null mutations in mecA, as well as in another gene, mecB, are known to bypass the requirements for nearly all of the competence regulatory genes, the comK requirement is not suppressed by mecA inactivation. Various competence regulatory genes (comA, srfA, degU, abrB, sin, and spo0A) are shown to be required for the expression of comK. srfA transcription is shown to occur equally in cells destined for competence and those destined not to become competent. In contrast, comK transcription is restricted to the presumptive competent cells. These and other results are combined to describe a regulatory pathway for competence.

Regulation of competence-specific gene expression by Mec-mediated protein-protein interaction in Bacillus subtilis

The expression of competence genes in Bacillus subtilis is controlled by a signal transduction cascade which increases the expression of a competence transcription factor (CTF, encoded by comK) during the transition from exponential growth to stationary phase. The transcription of CTF (ComK) is decreased by the product of the mecA gene, and this inhibition is relieved in response to an unknown signal received from upstream in the regulatory pathway. Inactivation of either mecA or another gene, mecB, results in overproduction of ComK. We show here that the concentration of MecA protein does not vary markedly with culture medium, as a function of growth stage, or in competent and noncompetent cells. We also show that MecA can interact directly with ComK. Finally, evidence is presented suggesting that MecB functions prior to MecA in the signaling pathway. A model is discussed which involves the sequestration of ComK by MecA binding and the release of the transcription factor when an appropriate signal is relayed to MecA by MecB.

Positive and negative hepatic regulation of the human type II phospholipase A2 gene

To identify the elements which regulate the liver transcription of the human type II phospholipase A2 gene and its stimulation by interleukin 6, the 5' flanking region from -1614 to +806 and several 3' and 5' deleted fragments have been analyzed in CAT assays. Negative regulatory elements have been located in the regions -1614 to -326 and +20 to +806. The fragment -326 to +20 contains the main elements required for the transcription as well as for the stimulation by interleukin 6. Footprinting assays have been performed on this region and showed four protected elements, A [-35;-6], B [-125;-86], C [-209;-176], and D [-247;-211]. Deletion of element D enhanced the transcription of the reporter gene 10.5-fold compared to the [-326;+20]-CAT construct. Further deletions up to position -87 which removed both the elements B and C or the substitution of element C by a nonspecific sequence lowered the promoter activity to 23% and 70% of the control, respectively. These results indicate that element C binds positive regulatory factors and element D binds a negative regulatory factor. Furthermore, stimulation by interleukin 6 is lost when element C is substituted or deleted. As shown by the footprinting and band shift assays, the transcription factors C/EBP alpha and C/EBP beta can bind to elements C and D but the dissociation constant (Kd) of C/EBP alpha is 10 times lower for element C (0.6 nM) than for element D (5.8 nM). Band shift experiments using rat liver nuclear extracts showed that element C formed four heat stable complexes, some of which could be supershifted by anti C/EBP alpha antibodies. The binding of C/EBP factors to element C was confirmed by competition with previously described oligonucleotide and nucleotide substitution of element C. Band shift experiments using rat liver nuclear extracts showed that element D formed one major DNA-protein complex. This complex could be competed out by oligonucleotides containing a cAMP responsive element (CRE) but not by oligonucleotides containing the binding site of C/EBP. However, anti-CREB antibodies did not supershift this complex. Methylation interference experiments showed the involvement of a G nucleotide upstream to the sequence homologous to CRE in the binding of the hepatic nuclear factors.(ABSTRACT TRUNCATED AT 400 WORDS)

Microvascular dysfunction in postischemic skeletal muscle

In recent years, considerable research efforts have been directed at elucidating the mechanisms underlying the pathophysiologic alterations associated with reperfusion (reoxygenation) of ischemic (hypoxic) skeletal muscle. This intensive effort has led to the accumulation of a large body of evidence supporting the concept that reactive oxygen metabolites, generated at the onset of reperfusion, initiate the formation and release of proinflammatory agents, which subsequently attract and activate granulocytes. The activated neutrophils adhere to the microvascular endothelium, extravasate, and release cytotoxic oxidants and hydrolytic enzymes. As a consequence of these pathologic events, vascular permeability and transcapillary fluid filtration are increased and the no-reflow phenomenon (ie, some capillaries fail to reperfuse upon reinstitution of blood flow) becomes apparent. These microvascular alterations may be of considerable functional importance since the marked accumulation of fluid in the interstitial spaces, coupled with the incomplete and maldistributed blood flow, increases the functional diffusion path length for nutrients. Thus cellular nutrition is limited during reperfusion, which in turn impairs the functional recovery of postischemic muscles. Moreover, the infiltrating neutrophils are able to direct a focussed attack on myocytes, thereby exacerbating contractile dysfunction and tissue injury during reperfusion. These observations indicate that alterations in the microcirculation play a critical role in the genesis of ischemia/reperfusion injury in skeletal muscle. This review summarizes the evidence we have accumulated in support of the view that reactive oxygen metabolites and neutrophils contribute to production of postischemic microvascular dysfunction and describes the experimental models we have used to examine the mechanisms involved in the pathogenesis of ischemia and reperfusion.

Sequence and properties of mecA, a negative regulator of genetic competence in Bacillus subtilis

The development of competence in Bacillus subtilis is regulated by growth conditions and several regulatory genes. In complex media competence development is poor, and there is little or no expression of late competence genes. mec mutations permit competence development and late competence gene expression in complex media, and bypass the requirements for many of the competence regulatory genes. In this paper we describe the cloning and characterization of mecA. The mecA gene product acts negatively in the development of competence. Null mutations in mecA allowed expression of a late competence gene comG, under conditions where it is not normally expressed, including in complex media and in cells mutant for several competence regulatory genes. Overexpression of MecA from a multicopy plasmid resulted in inhibition of comG transcription. The DNA sequence of mecA was determined and the predicted gene product showed no significant similarity to any protein in the database. Expression of a mecA-lacZ translational fusion was constitutive during growth and did not vary significantly in the different media tested. The role of mecA in competence development and other stationary phase phenomena is discussed.

Recurrent erythema migrans despite extended antibiotic treatment with minocycline in a patient with persisting Borrelia burgdorferi infection

Erythema migrans recurred in a patient 6 months after a course of treatment with minocycline for Lyme disease. Polymerase chain reaction on heparinized peripheral blood at that time demonstrated the presence of Borrelia burgdorferi-specific DNA. The patient was seronegative by Lyme enzyme-linked immunosorbent assay but showed suspicious bands on Western blot. Findings of a Warthin-Starry stain of a skin biopsy specimen of the eruption revealed a Borrelia-compatible structure. Reinfection was not believed to have occurred. Further treatment with minocycline led to resolution of the erythema migrans.

A novel inositol mono-phosphatase inhibitor from Memnoniella echinata. Producing organism, fermentation, isolation, physicochemical and in vitro biological properties

A novel inositol mono-phosphatase inhibitor, L-671,776 (1), was discovered from a culture of the hyphomycete, Memnoniella echinata (ATCC 20928). 1 has a molecular weight of 388 and a molecular formula of C23H32O5. The mode of inhibition is non-competitive, with a Ki of 450 microM. It shows no inhibition of myo-inositol 1,4-bisphosphate 1-phosphatase or myo-inositol 1,4,5-triphosphate 5-phosphatase, although it weakly inhibits myo-inositol 1,4,5-triphosphate 3-kinase (IC50 = 3 mM). It elevates inositol monophosphates in rat parotid slices (EC50 approximately 3 mM), but abolishes agonist effects. It also produces short-lived contraction of guinea pig trachea at 300 microM.

[Pharmacological studies on erzhi pills]

The experimental results show that Erzhi Pills can markedly increase the weights of immunological organs in mice and antagonize the immunosuppressive action of prednisolone. The diameter of SRID precipitating ring, the hemolytic ability of PFC and the clearance rate of i.v. charcoal particles in mice can all be increased by the pills. Erzhi Pills also protect mice from CCl4 intoxication. Steamed Ligustrum lucidum has the same action as Erzhi Pills.

Evidence for a new Escherichia coli protein resembling a lysyl-tRNA synthetase

The amino acid sequence deduced from the nucleotide sequence of an open reading frame adjacent to the frdA gene of Escherichia coli shows 30.5% identity with the C terminus of Escherichia coli lysyl-tRNA synthetases. The three motifs characteristic of aminoacyl-tRNA synthetases of class 2 are recognizable within this sequence.