The kinetic mechanism of 5-enolpyruvylshikimate-3-phosphate synthase from a gram-positive pathogen Streptococcus pneumoniae

The Streptococcus pneumoniae 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase is a potential novel antibacterial target. The enzyme catalyzes a reversible transfer of an enolpyruvyl group from phospho(enol)pyruvate (PEP) to shikimate 3-phosphate (S3P) to give EPSP with the release of inorganic phosphate (Pi). Understanding the kinetic mechanism of this enzyme is crucial to the design of novel inhibitors of this enzyme that may have potential as antibacterial agents. Steady-state kinetic studies of product inhibition and inhibition by glyphosate (GLP) have demonstrated diverse inhibition patterns of the enzyme. In the forward reaction, GLP is a competitive inhibitor with respect to PEP, but an uncompetitive inhibitor relative to S3P. Product inhibition shows that EPSP is a competitive inhibitor versus both PEP and S3P, suggesting that the forward reaction follows a random sequential mechanism. In the reverse reaction, GLP is an uncompetitive inhibitor versus EPSP, but a noncompetitive inhibitor versus Pi. This indicates that a non-productive quaternary complex might be formed between the enzyme, EPSP, GLP and Pi. Product inhibition in the reverse reaction has also been investigated. The inhibition patterns of the S. pneumoniae EPSP synthase are not entirely consistent with those of EPSP synthases from other species, indicating that EPSP synthases from different organisms may adopt unique mechanisms to catalyze the same reactions.

Paclitaxel, cisplatin, and 5-fluorouracil for patients with advanced or recurrent squamous cell carcinoma of the head and neck

BACKGROUND

The combination of cisplatin and 5-fluorouracil (5-FU) is considered standard therapy for patients with recurrent or metastatic squamous cell carcinoma of the head and neck (SCCHN). Paclitaxel has exhibited single-agent activity in patients with this disease. The authors conducted this study to evaluate the feasibility and efficacy of combining paclitaxel with cisplatin and 5-FU for patients with advanced or recurrent SCCHN.

METHODS

Patients with recurrent, metastatic, or locally advanced SCCHN who had measurable or evaluable disease and no prior chemotherapy were eligible. The starting dose level consisted of paclitaxel 135 mg/m(2) on Day 1, cisplatin 75 mg/m(2) on Day 2, and 5-FU 1 gm/m(2)/day on Days 2-6. Due to Grade 4 mucositis, dose level 1 of 5-FU was reduced to 800 mg/m(2)/day on Days 2-6 (for 7 patients), and subsequently the 5-FU dose was adjusted to 1 gm/m(2)/day on Days 2-5 (for 17 patients).

RESULTS

Twenty-five patients were enrolled, with a median age of 60 years and a median Southwest Oncology Group performance status of 1. Of the 25 patients, 16 had recurrent disease, 3 had metastatic disease at diagnosis, and 6 had untreated locally advanced SCCHN. Ninety-nine courses of therapy were administered, with a median of 5 courses. Major toxicities were neutropenia and mucositis. Significant neurotoxicity or nephrotoxicity were not observed. There were two treatment-related deaths (one each due to mucositis and neutropenic pneumonia), and these precluded further dose escalation. Fifteen of the 25 patients (60%) achieved a major response. Of significance is the response rate of 58% (11 of 19 patients) in those with recurrent or metastatic disease who had a duration of response ranging from 3 to 19+ months. Two of these 19 patients continue to be in remission of 19+ and 15+ months' duration, respectively. The median survival for patients with recurrent or metastatic disease was 6 months (range, 1-26 months), with a 1-year survival rate of 37%.

CONCLUSIONS

The dose and schedule for the combination of paclitaxel, 5-FU, and cisplatin as determined in this study are feasible, with encouraging outcomes and activity in patients with recurrent or metastatic SCCHN. The results of this trial warrant larger-scale evaluation to determine the role of this combination in the management of patients with this disease.

Geranylgeranylated RhoB mediates suppression of human tumor cell growth by farnesyltransferase inhibitors

Farnesyltransferase inhibitors (FTIs) are in clinical trials, but their mechanism of action is not fully understood. We have shown that FTI treatment rapidly elevates the level of geranylgeranylated RhoB in cells and that this event is sufficient to inhibit cell cycle transit and reverse malignant transformation without affecting normal cells. However, because these observations were made in rodent fibroblast models in which transformation was driven by defined genetic alterations, it remained to be established whether RhoB-GG was relevant to the antineoplastic effects of FTIs in human epithelial tumor cells with diverse genetic backgrounds. In this study, we show that elevated levels of RhoB-GG are sufficient to block the proliferation of FTI-sensitive but not FTI-resistant human carcinoma cells. RhoB-GG induced the cell cycle kinase inhibitor p21(WAF1) in a p53-dependent manner, similar to FTI treatment, but this event was dispensable because RhoB-GG could still inhibit the growth of p53-null cells that lacked p21WAF1 activation. Consistent with actions beyond G1-phase arrest, certain cell lines exhibited accumulation in G2-M phase or an increased apoptotic index in response to RhoB-GG. We concluded that RhoB-GG suppressed human tumor cell proliferation by more than one mechanism and that it promoted apoptosis as well as inhibited cell cycle transit in malignant epithelial cells. These findings suggest how FTIs suppress the growth of human tumor cells that lack Ras mutations.

Multidrug resistance phenotype in high grade soft tissue sarcoma: correlation of P-glycoprotein immunohistochemistry with pathologic response to chemotherapy

BACKGROUND

P-glycoprotein-mediated drug efflux has been implicated as an important mechanism of multidrug resistance (MDR) in cancer. Its role in chemotherapy resistance in soft tissue sarcoma is unclear.

METHODS

Tumor specimens prior to and following neoadjuvant chemotherapy from 29 cases of high grade soft tissue sarcoma were analyzed with 2 monoclonal antibodies (C494 and JSB-1) that recognize different epitopes of P-glycoprotein. Staining intensity was graded 0 = negative, 1 = equivocal, 2 = moderate, 3 = strong. Only cases with Grade 2 or 3 staining intensity with both antibodies were considered MDR positive. The resection specimens were evaluated for tumor necrosis postchemotherapy. Pathologic response was graded as good for <15%, moderate for 15-50%, or poor for >50% posttreatment tumor viability.

RESULTS

Of the 29 pretreatment specimens, 10 (34%) were MDR positive and 19 (66%) were MDR negative. Pathologic response to treatment was characterized as good in 6, moderate in 7, and poor in 16 patients. Of the MDR positive biopsies, 9 (90%) had poor response, compared with 7 (36%) in the MDR negative biopsy group (P = 0.0078). None of the cases with MDR positive biopsies had a good response, compared with 6 cases in which biopsies were MDR negative (32%) (P = 0.057). Only one MDR negative case became MDR positive posttreatment.

CONCLUSIONS

Expression of MDR phenotype is found in approximately one-third of high grade soft tissue sarcomas. These preliminary data show a significant correlation between MDR phenotype and poor pathologic response to chemotherapy, and suggest that MDR induction by chemotherapy in soft tissue sarcoma is an uncommon event.

VEGF and VEGF type C play an important role in angiogenesis and lymphangiogenesis in human malignant mesothelioma tumours

The vascular endothelial growth factor (VEGF) family is a novel regulator of endothelial cell proliferation. We assessed the mRNA expression of VEGF, VEGF type C (VEGF-C) and their receptors together with the microvessel density (VD) and microlymphatic vessel density (LVD) in pursuit of their connection and prognostic value in malignant pleural mesothelioma (MPM). We used four human MPM cell lines, 54 MPM tumours and five normal pleural tissues. Expression levels for receptors and ligands were assessed by semiquantitative reverse transcriptase polymerase chain reaction analysis. Microvessels were highlighted by immunohistochemical staining for factor VIII. The discrimination of lymphatics was performed by enzyme-histochemistry for 5'-nucleotidase after adequate inhibition of non-specific activity. The expression levels of VEGF, VEGF-C and VEGFRs were high in all MPM cell lines. The percentages of tumours with higher expression compared to the mean values of normal pleural tissues were 31.5% (17/54) for VEGF, 66.7% (36/54) for VEGF-C, 20.4% (11/54) for fms-like tyrosine kinase (flt)-1, 42.6% (23/54) for kinase insert domain-containing recepter (KDR) and 59.3% (32/54) for flt-4. Significant positive correlations were found between VEGF-C and flt-4, VEGF and KDR, VEGF and flt-1 in tumour tissues. The association between LVD and VEGF-C expression level was especially strong (P< 0.0001, r= 0.63). There were also significant correlations between LVD and flt-4, and VD and VEGF. No correlation, however, was found between LVD and nodal metastasis. VD was a negative prognostic indicator in this study. The associations between VEGFNEGF-C and vessel density suggest that these factors play an important role in angiogenesis and lymphangiogenesis in this tumour, and assessment of vascularity may be a useful prognostic indicator for MPM patients.

Activation of the PI3'K-AKT pathway masks the proapoptotic effects of farnesyltransferase inhibitors

Farnesyltransferase inhibitors (FTIs) usually cause growth inhibition, but in certain preclinical settings they have been shown to induce apoptosis, a clinically desirable response. In this study, we show that the proapoptotic effects of FTIs in Ras-transformed cells are masked by activation of phosphatidylinositol 3'-kinase (PI3'K) or AKT, which are controlled by cytokines and integrins. The results implied that FTIs disrupt a signal that is crucial for survival of malignant cells, but not normal cells, if the PI3'K-AKT pathway is inactivated. Our findings have implications for clinical applications of FTIs where apoptotic responses would be preferred.

Mechanism for elimination of a tumor suppressor: aberrant splicing of a brain-specific exon causes loss of function of Bin1 in melanoma

Loss of tumor suppressors that restrain important oncoproteins such as c-Myc may contribute to malignant progression. Bin1 is an adapter protein with features of a tumor suppressor that was identified through its interaction with and inhibition of the oncogenic properties of c-Myc. In this study, we analyzed the patterns of Bin1 expression in normal melanocytes and melanoma cells at different stages of tumor progression. Evidence is provided that Bin1 function is abrogated in melanoma cells by a mechanism based on aberrant splicing of a tissue-specific exon. Specifically, most melanoma cells inappropriately expressed exon 12A, which is spliced alternately into Bin1 isoforms found in brain but not into isoforms found in melanocytes and many other nonneuronal cells. Exon 12A sequences abolished the ability of Bin1 to inhibit malignant transformation by c-Myc or adenovirus E1A. Similarly, these sequences abolished the ability of Bin1 to induce programmed cell death in melanoma cells that endogenously expressed exon 12A. Our findings suggest that aberrant splicing of Bin1 may contribute to melanoma progression, and they define a mechanism by which the activity of a tumor suppressor can be eliminated in cells.

Effects of prenatal cocaine exposure on amphetamine-induced dopamine release in the caudate nucleus of the adult rabbit

Acute amphetamine (AMPH) challenge has been used to probe the neurochemical and behavioral integrity of dopaminergic neurons under various conditions including prenatal cocaine exposure. In this study, we employed in vivo microdialysis to examine the effects of prenatal cocaine exposure on AMPH-induced dopamine (DA) release in the caudate nucleus of the awake adult rabbit. Pregnant rabbits were given intravenous injections of either saline or cocaine (4 mg/kg) twice a day from gestational day 8 (G8) through G29. Microdialysis was performed in adult saline and cocaine progeny at approximately postnatal day 70 (P70). There were no significant differences between cocaine and saline progeny in their basal concentrations of DA or its metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA). AMPH (5 mg/kg, i.v.) significantly increased extracellular DA in the caudate of both groups. However, AMPH-induced DA release was 2 to 3-fold greater in cocaine progeny than in the saline controls. Although, DOPAC decreased in both groups following AMPH injection, there was no significant group effect. In addition, there were no significant changes in concentrations of HVA. AMPH is known to release DA by a mechanism of exchange diffusion via the presynaptic DA transporter (DAT). Therefore, we examined the binding of [(3)H]WIN 35,428 to membrane fractions prepared from fresh caudate tissue to determine whether prenatal exposure to cocaine had altered the density (B(max)) or affinity (K(d)) of the DAT. While the B(max) for [(3)H]WIN 35,428 binding increased 3-fold between P3 and P120, there were no significant differences between saline and cocaine progeny at any age examined. The K(d) for [(3)H]WIN 35,428 binding did not change with postnatal age and did not differ between cocaine and saline progeny. These findings suggest that prenatal exposure to cocaine produces a long-term increase in the size of the presynaptic, AMPH releasable, cytoplasmic pool of DA.

Bin1 functionally interacts with Myc and inhibits cell proliferation via multiple mechanisms

The tumor suppressor Bin1 was identified through its interaction with the N-terminal region of Myc which harbors its transcriptional activation domain. Here we show that Bin1 and Myc physically and functionally associate in cells and that Bin1 inhibits cell proliferation through both Myc-dependent and Myc-independent mechanisms. Bin1 specifically inhibited transactivation by Myc as assayed from artificial promoters or from the Myc target genes ornithine decarboxylase (ODC) and alpha prothymosin (pT). Inhibition of ODC but not pT required the presence of the Myc binding domain (MBD) of Bin1 suggesting two mechanisms of action. Consistent with this possibility, a non-MBD region of Bin1 was sufficient to recruit a repression function to DNA that was unrelated to histone deacetylase. Regions outside the MBD required for growth inhibition were mapped in Ras cotransformation or HepG2 hepatoma cell growth assays. Bin1 required the N-terminal BAR domain to suppress focus formation by Myc whereas the C-terminal U1 and SH3 domains were required to inhibit adenovirus E1A or mutant p53, respectively. All three domains contributed to Bin1 suppression of tumor cell growth but BAR-C was most crucial. These findings supported functional interaction between Myc and Bin1 in cells and indicated that Bin1 could inhibit malignant cell growth through multiple mechanisms.

[The relationship between IgA nephropathy and HBV infection]

OBJECTIVE

To clarify the correlation between hepatitis B virus (HBV) infection and the pathogenesis of IgA nephropathy.

METHODS

Ninety-one cases of primary IgA nephropathy were investigated by using in situ hybridization(HBV DNA), immunohistochemistry (HBAg) and HBV DNA-HBAg double staining techniques. In some of the cases, Southern blot analysis and serologic HBV infectious markers were detected also.

RESULTS

The positive rate of HBAg in renal tissue detected by immunohistochemistry was 69% (63/91) and that of the HBV DNA detected by in situ hybridization was 43% (39/91). Eighteen of 27 cases showed HBV DNA positive in Southern blot analysis, and all of the positive cases were identified to be the integrated form. Among them, 17 cases were HBAg detectable in renal tissue by immunohistochemistry and 16 cases were HBV DNA detectable by in situ hybridization simultaneously. The positive rate of the expression of HBcAg [77% (30/39)] and HBsAg [72% (28/39)] of the tubular epithelial cells with HBV DNA signals in nuclears by in situ hybridization was significantly higher than that of the cells without HBV DNA signals(10%, 21%). The double staining showed that most of the HBV DNA positive tubular epithelial cells coexpressed HBsAg and(or) HBcAg.

CONCLUSION

The renal tissue of some of IgA nephropathy infected with HBV directly and express HBAg in situ.

Elevation of alpha2(I) collagen, a suppressor of Ras transformation, is required for stable phenotypic reversion by farnesyltransferase inhibitors

Farnesyltransferase inhibitors (FTIs) are a novel class of anticancer drugs that can reverse Ras transformation. One of the intriguing aspects of FTI biology is that continuous drug exposure is not necessary to maintain phenotypic reversion. For example, after a single exposure to FTIs, Ha-Ras-transformed fibroblasts revert to a flat and anchorage-dependent phenotype that persists for many days after processed Ras has returned to pretreatment levels. In this study, we show that persistence of the reverted state is mediated by elevated expression of the collagen isoform alpha2(I), a suppressor of Ras transformation the transcription of which is repressed by activated Ras and derepressed by FTI treatment. To our knowledge, this is the first report identifying an FTI-regulated gene which is linked to phenotypic reversion. The finding that extracellular matrix alterations can influence the kinetics of reversion supports our assertion that Rho-regulated cell adhesion parameters are a crucial determinant of the cellular response to FTIs.

Prognostic significance of p53 gene mutations in laryngeal cancer

OBJECTIVE/HYPOTHESIS

We examined whether p53 gene mutations were predictive of clinical behavior in laryngeal cancer.

STUDY DESIGN

Retrospective study of 45 patients with laryngeal cancer from 1985 to 1997.

METHODS

DNA was extracted from tumor tissue and subject to polymerase chain reaction single-strand conformational polymorphism (PCR-SSCP) as well as DNA sequencing. The clinical outcome was correlated to the presence or absence of a p53 mutation.

RESULTS

The p53 gene was analyzed by direct DNA sequencing and was found to be mutated in 33% (15/45) of patients. The presence of a p53 mutation was associated with a significant improvement in overall survival (80% vs. 43%, P < .03) and a trend toward improved disease-free survival (87% vs. 60%, P = .08). When other prognostic factors were adjusted, multivariate analysis revealed a trend toward improvement in overall survival as well as disease-free survival.

CONCLUSION

Depending on the location of a p53 mutation, the suppressive functions or clinical outcome may or may not be affected. Fifty-three percent of mutations were detected in nonconserved regions as opposed to 17% as reported in colon cancer. In colon cancer, mutations in conserved regions of the p53 gene predicted a poorer survival, whereas nonconserved gene mutations were not predictive. In our group of patients. p53 mutations predicted a better prognosis, which may be due to a large proportion of mutations that lie within nonconserved areas. The predictive power of p53 gene mutations may depend on functional loss and inactivation of highly conserved areas and must be tested in a prospective trial.

Cell growth inhibition by farnesyltransferase inhibitors is mediated by gain of geranylgeranylated RhoB

Recent results have shown that the ability of farnesyltransferase inhibitors (FTIs) to inhibit malignant cell transformation and Ras prenylation can be separated. We proposed previously that farnesylated Rho proteins are important targets for alternation by FTIs, based on studies of RhoB (the FTI-Rho hypothesis). Cells treated with FTIs exhibit a loss of farnesylated RhoB but a gain of geranylgeranylated RhoB (RhoB-GG), which is associated with loss of growth-promoting activity. In this study, we tested whether the gain of RhoB-GG elicited by FTI treatment was sufficient to mediate FTI-induced cell growth inhibition. In support of this hypothesis, when expressed in Ras-transformed cells RhoB-GG induced phenotypic reversion, cell growth inhibition, and activation of the cell cycle kinase inhibitor p21WAF1. RhoB-GG did not affect the phenotype or growth of normal cells. These effects were similar to FTI treatment insofar as they were all induced in transformed cells but not in normal cells. RhoB-GG did not promote anoikis of Ras-transformed cells, implying that this response to FTIs involves loss-of-function effects. Our findings corroborate the FTI-Rho hypothesis and demonstrate that gain-of-function effects on Rho are part of the drug mechanism. Gain of RhoB-GG may explain how FTIs inhibit the growth of human tumor cells that lack Ras mutations.

The role of RBF in the introduction of G1 regulation during Drosophila embryogenesis

The first appearance of G1 during Drosophila embryogenesis, at cell cycle 17, is accompanied by the down-regulation of E2F-dependent transcription. Mutant alleles of rbf were generated and analyzed to determine the role of RBF in this process. Embryos lacking both maternal and zygotic RBF products show constitutive expression of PCNA and RNR2, two E2F-regulated genes, indicating that RBF is required for their transcriptional repression. Despite the ubiquitous expression of E2F target genes, most epidermal cells enter G1 normally. Rather than pausing in G1 until the appropriate time for cell cycle progression, many of these cells enter an ectopic S-phase. These results indicate that the repression of E2F target genes by RBF is necessary for the maintenance but not the initiation of a G1 phase. The phenotype of RBF-deficient embryos suggests that rbf has a function that is complementary to the roles of dacapo and fizzy-related in the introduction of G1 during Drosophila embryogenesis.

Accrual to breast cancer clinical trials at a university-affiliated hospital in metropolitan Detroit

Despite the large number of available studies, most women with breast cancer do not participate in clinical trials, and this is especially true among lower income and minority women. In this study the authors surveyed the practice patterns of four medical oncologists who comprised the clinical breast service at a large urban university hospital to develop a better understanding of the clinical trials enrollment process for women with breast cancer. Of 136 new female breast cancer patients seen by the four physicians over a 7-month period, there were 47 women (34%) offered participation in a clinical trial, and 16 women (12%) were eventually enrolled. Women who were offered participation were more likely to be younger (p = 0.068) and to have earlier stage disease then were women not offered participation (p = 0.008). Women enrolled into a trial were also more likely to be younger, although this difference was not statistically significant (p = 0.114). Patient race was not associated with the accrual or enrollment process. Over half of the women were not offered participation in clinical trials because of the lack of available studies. Further work evaluating the process of patient enrollment and physician and patient barriers is necessary to develop effective strategies for recruitment into breast cancer clinical trials.

Green fluorescent protein as a reporter to monitor gene expression and food colonization by Aspergillus flavus

Transformants of Aspergillus flavus containing the Aequorea victoria gfp gene fused to a viral promoter or the promoter region and 483 bp of the coding region of A. flavus aflR expressed green fluorescence detectable without a microscope or filters. Expression of green fluorescent protein fluorescence was correlated with resistance to aflatoxin accumulation in five corn genotypes inoculated with these transformants.

Antiproliferative effect of elevated glucose in human microvascular endothelial cells

Diabetic microangiopathy has been implicated as a fundamental feature of the pathological complications of diabetes including retinopathy, neuropathy, and diabetic foot ulceration. However, previous studies devoted to examining the deleterious effects of elevated glucose on the endothelium have been performed largely in primary cultured cells of macrovessel origin. Difficulty in the harvesting and maintenance of microvascular endothelial cells in culture have hindered the study of this relevant population. Therefore, the objective of this study was to characterize the effect of elevated glucose on the proliferation and involved signaling pathways of an immortalized human dermal microvascular endothelial cell line (HMEC-1) that possess similar characteristics to their in vivo counterparts. Human dermal microvascular endothelial cells (HMEC-1) were grown in the presence of normal (5 mM) or high D-glucose (20 mM) for 14 days. The proliferative response of HMEC-1 was compared under these conditions as well as the cAMP and PKC pathways by in vitro assays. Elevated glucose significantly inhibited (P < 0.05) HMEC-1 proliferation after 7, 10, and 14 days. This effect was not mimicked by 20 mM mannitol. The antiproliferative effect was more pronounced with longer exposure (1-14 days) to elevated glucose and was irreversible 4 days after a 10-day exposure. The antiproliferative effect was partially reversed in the presence of a PKA inhibitor, Rp-cAMP (10-50 microM), and/or a PKC inhibitor, Calphostin C (10 nM). HMEC-1 exposed to elevated glucose (20 mM) for 14 days caused an increase in cyclic AMP accumulation, PKA, and PKC activity but was not associated with the activation of downstream events such as CRE and AP-1 binding activity. These data support the hypothesis that HMEC-1 is a suitable model to study the deleterious effects of elevated glucose on microvascular endothelial cells. Continued studies with HMEC-1 may prove advantageous in delineation of the molecular pathophysiology associated with diabetic microangiopathy.

Phase II study of hyperfractionated radiotherapy and concurrent weekly alternating chemotherapy in limited-stage small cell lung cancer

Despite recent advances in combined modality therapy, long-term survival remains elusive in most patients with limited-stage small cell lung cancer (SCLC). The present study was designed to evaluate the activity and toxicity of concurrent hyperfractionated radiotherapy and weekly, alternating-regimen chemotherapy. Twelve patients with limited-stage SCLC and performance status 0-1 were treated with cyclophosphamide 250 mg/m2, etoposide 100 mg/m2, and cisplatin 50 mg/m2 on day 1 every other week, and vincristine 1 mg/m2 on day 8, and ifosfamide 1.2 mg/m2 on days 8 and 9 every other week. Hyperfractionated thoracic radiotherapy, consisting of three daily doses of 1.1 Gy for 20 days to a total dose of 66 Gy, was started on day 1 of chemotherapy. Ten patients (83%) exhibited an objective response (9 CRs and 1 PR) with a median duration of response of 8.6 months. Two complete responders died at 50 and 53 months without evidence of progression and two remain alive and free of SCLC at 73 and 87 months. Median survival was 19.8 months with 2- and 5-year survival rates of 50 and 17%, respectively. Severe toxicity, including grade 3-4 esophagitis (67%) and granulocytopenia (83%), as well as debilitating fatigue and pneumonitis, prompted early termination of the trial. Hyperfractionated radiotherapy and concurrent weekly alternating-regimen chemotherapy resulted in promising response and survival rates, but induced excessive toxicity, in patients with limited-stage SCLC.

Induction of interleukin (IL)-1 alpha and beta gene expression in human keratinocytes exposed to repetitive strain: their role in strain-induced keratinocyte proliferation and morphological change

Recent studies in our laboratory have demonstrated that mechanical strain alters many facets of keratinocyte biology including proliferation, protein synthesis, and morphology. IL-1 is known to play an important role in the autocrine regulation of these basic cellular properties under basal and stimulated conditions. However, it is not known whether IL-1 plays a role in strain-induced alteration of keratinocyte biology. Thus, the objective of this study was to test the hypothesis that cyclic strain stimulates IL-1 expression and that strain-induced changes in keratinocyte function is regulated by IL-1. To test this hypothesis, we examined the effect of cyclic strain (10% average deformation) on keratinocyte IL-1 gene expression and the effect of neutralizing antibodies of IL-1 alpha and IL-1 beta on strain-induced changes in keratinocyte proliferation, morphology, and orientation. Northern blot analyses demonstrated that steady state levels of IL-1 alpha and beta mRNA were elevated by 4 h, peaked at 1 2 h of cyclic strain (IL-1 alpha, 304+/-14.2%; IL-1 beta, 212+/-5.6% increase vs. static controls) and decreased gradually by 24 h. IL-1 antibodies (IL-1 alpha, 0.01 microg/ml; IL-1 beta, 0.01 microg/ml) significantly blocked strain-induced keratinocyte proliferation as well as the basal rate of proliferation. In contrast, IL-1 antibodies (IL-1 alpha, 0.01 microg/ml; IL-1 beta, 0.1 microg/ml) had no effect on strain-induced morphological changes such as elongation and alignment. We conclude that mechanical strain induces IL-1 mRNA expression in keratinocytes. The role of IL-1 in mediating strain-induced changes in keratinocyte biology remains to be determined but appears to be independent of morphological changes.

Successful allogeneic bone marrow transplantation in selected patients over 50 years of age--a single institution's experience

As allogeneic bone marrow transplantation (BMT) is a procedure with a higher risk of morbidity and mortality in older patients, many institutions place a limit of 50 to 55 years for allogeneic BMT. Consequently, older patients may not be offered potentially curative treatment for otherwise poor prognosis diseases such as AML or myelodysplastic syndrome. We compared the outcome of 59 patients aged over 50, 124 aged 40-50, and 253 aged 18-39 years who underwent allogeneic BMT in our institution between August 1987 and April 1996. Our results show little influence of age on outcome when comparing patients over 50 years with patients 40-50 years. Apart from an initial higher transplant mortality rate, overall survival was not significantly different between the three age groups. The 1-year and 2-year overall survival rates were 57% and 48%, 57% and 48%, and 62% and 58% for the >50 years, 40-50 years, and <40 years patients, respectively. The incidence of GVHD was also comparable. We conclude that allogeneic BMT can be performed in selected patients over the age of 50 years with acceptable morbidity and mortality and that older patients should not be denied this treatment based on age alone.

Phase II trial of paclitaxel and carboplatin in the treatment of advanced urothelial carcinoma

PURPOSE

Both paclitaxel and carboplatin have single-agent activity against carcinoma of the urothelium. We evaluated the combination of paclitaxel and carboplatin in the treatment of advanced cancers of the urothelium.

PATIENTS AND METHODS

Patients with cancers of the urothelium who had no prior chemotherapy (prior adjuvant chemotherapy > 6 months allowed) were eligible for treatment. Eligibility requirements were performance status of 2 or less, creatinine level less than 2.0 mg/dL, granulocyte count (AGC) 1,500/microL or greater, platelet count 100,000/microL or greater, and total bilirubin level less than 1.5 mg/dL. Paclitaxel 200 mg/m2 followed by carboplatin (area under the curve [AUC] 5, Calvert formula) were administered every 21 days. Patients were evaluated for toxicity weekly and assessed for response every 6 weeks.

RESULTS

Thirty-six patients were entered onto the study and 35 patients were assessable for response. A total of 184 cycles were administered (median, six cycles per patient). Nine patients required one dose reduction, and seven patients required two dose reductions for a nadir AGC less than 500/microL, with only one episode of febrile neutropenia and sepsis. Myalgias and arthralgias of grades 1 to 2 occurred in 16 patients and usually lasted 2 to 3 days after treatment. There were no treatment delays because of toxicity. There were 18 responses; seven complete responses (CRs) and 11 partial responses (PRs) (response rate 51.5%; 95% confidence interval, 35 to 68). Median response durations for CR and PR were 6 and 4 months, respectively. Overall median survival was 9.5 months.

CONCLUSION

The combination of paclitaxel and carboplatin is an active and well-tolerated regimen for the treatment of advanced urothelial carcinoma. Because of the modest toxicity of this combination, paclitaxel and carboplatin should be considered for addition to other agents with activity in urothelial carcinomas.

Regulation of PDGF-B in endothelial cells exposed to cyclic strain

The present study was designed to examine the regulation by cyclic strain of endothelial cell (EC) platelet-derived growth factor-B chain (PDGF-B) expression. We demonstrate in this study that bovine aortic ECs subjected to 10% (but not 6%) average strain resulted in a 2.6-fold increase in PDGF-B steady state mRNA and immunoreactive protein. Nuclear runoff transcription assays confirmed the induction of PDGF-B transcripts. To address the regulation of PDGF-B gene expression by cyclic strain, we transfected bovine aortic ECs with a construct containing 450 bp of human PDGF-B promoter sequence coupled to chloramphenicol acetyltransferase (CAT), and found that subjecting these cells to 10% average strain resulted in a twofold increase in CAT activity by 4 hours. Analysis of nested 5' deletions of the promoter transfected into ECs demonstrated a 55% drop-off in activity between position -313 and -153, with no induction of activity with the - 101-bp minimal promoter. Since a shear stress response element (SSRE) is located at position -125, we tested the hypothesis that the SSRE site was necessary and/or sufficient for induction of PDGF-B activity with strain. Electromobility shift assays revealed that nuclear proteins from ECs exposed to strain for short intervals (30 minutes) bound to the PDGF-B SSRE. However, transfection of ECs with hybrid promoter constructs containing the SV40 sequence promoter downstream of the SSRE or the -153 PDGF-B promoter sequence bearing a mutation in the SSRE demonstrated that the SSRE was not necessary for inducible reporter gene expression in ECs exposed to cyclic strain.

[Serological survey of human T lymphotropic virus type I (HTLV-1) IgG antibody in south region of Xinjiang]

Human T lymphotropic virus type-1 (HTLV-1) is endemic in southwestern Japan, Seychelles Islands, Caribbean basin, Brazil, and Sub Saharan Africa. Recently, the prevalence of HTLV-1 of domestic source has been reported from Beijing, Fujian and so forth. The object of our study is to know whether the prevalence of HTLV-1 is present in Xinjiang. We collected 2642 serm samples of various ages and different nationalities (Uigur, Han and Khalkhas) from south region of Xinjiang and tested for determination of HTLV-1 IgG antibody by IFA. The results showed that the total positive rate of HTLV-1 IgG was 0.34% (9/2642), of which Uigur nationality was 0.74% (8/1082), Khalkhas nationality was 0.21 (1/471), Han nationality was zero (0/1089). This data indicated that there are HTLV-1 infection among the population of Xinjiang and especially in Uigur and Khalkhas. Why did the minority nationalities have relatively high frequency of HTLV-1 infection? This needs to be studied further.

Regulation of tPA in endothelial cells exposed to cyclic strain: role of CRE, AP-2, and SSRE binding sites

We have previously reported that exposure of cultured bovine aortic endothelial cells (EC) to 10% average strain resulted in an increase in tissue plasminogen activator (tPA) mRNA, immunoreactive tPA protein, and tPA activity in the medium. The present study was designed to examine the regulation of tPA gene expression in EC by cyclic strain. We performed a functional analysis of the tPA promoter by transfecting bovine aortic EC with a 1.4-kilobase (kb) construct of the human tPA promoter coupled to chloramphenicol acetyltransferase. We found that subjecting the EC to 10% average strain (and not 6% average strain) resulted in a 2.6-fold increase in activity of the 1.4-kb tPA promoter by 4 h. Analysis of deletion mutants of the promoter transfected into EC demonstrated a 60% drop-off in activity between position -145 and -105. Deoxyribonuclease I protection analysis of the segment downstream of position -196 suggested involvement of activator protein-2 (AP-2) and adenosine 3',5'-cyclic monophosphate-responsive element (CRE)-like binding sites, which was confirmed by electrophoretic mobility shift assays. Site-directed mutants of either the AP-2 or CRE-like regions resulted in a 65% decrease in activity compared with the wild type. Double mutations abolished basal transcription and any strain-induced activity. A shear stress responsive element (SSRE) binding site is present at -945, but site-directed mutants did not show any drop in activity compared with wild type by cyclic strain. These studies demonstrate that cyclic strain regulates tPA gene transcription in bovine aortic EC and that this transcriptional activation is dependent on factors that are similar to those activated with phorbol ester.

Harmaline competitively inhibits [3H]MK-801 binding to the NMDA receptor in rabbit brain

Harmaline, a beta-carboline derivative, is known to produce tremor through a direct activation of cells in the inferior olive. However, the receptor(s) through which harmaline acts remains unknown. It was recently reported that the tremorogenic actions of harmaline could be blocked by the noncompetitive NMDA channel blocker, MK-801. This study examined whether the blockade of harmaline's action, in the rabbit, by MK-801 was due to a pharmacological antagonism at the MK-801 binding site. This was accomplished by measurement of [3H]MK-801 binding in membrane fractions derived from tissue containing the inferior olivary nucleus and from cerebral cortex. Harmaline completely displaced saturable [3H]MK-801 binding in both the inferior olive and cortex with apparent IC50 values of 60 and 170 microM, respectively. These IC50 values are consistent with the high doses of harmaline required to produce tremor, e.g., 10-30 mg/kg. Non-linear curve fitting analysis of [3H]MK-801 saturation experiments indicated that [3H]MK-801 bound to a single site and that harmaline's displacement of [3H]MK-801 binding to the NMDA receptor was competitive as indicated by a shift in Kd but not in Bmax. In addition, a Schild plot gave a slope that was not significantly different from 1 indicating that harmaline was producing a displacement of [3H]MK-801 from its binding site within the NMDA cation channel and not through an action at the glutamate or other allosteric sites on the NMDA receptor. These findings provide in vitro evidence that the competitive blockade of harmaline-induced tremor by MK-801 occurs within the calcium channel coupled to the NMDA receptor. Our hypothesis is that harmaline produces tremor by acting as an inverse agonist at the MK-801 binding site and thus opening the cation channel.

Transplantation in patients with multiple myeloma: a multicenter comparative analysis of peripheral blood stem cell and allogeneic transplant

We performed a multicenter comparative analysis of autologous peripheral blood stem cell transplantation (PBSCT) and allogeneic bone marrow transplantation (alloBMT) in multiple myeloma. Forty-eight consecutive patients received either PBSCT (24 patients) or alloBMT (24 patients) at one of three institutions in the study group. Preparatory regimens consisted of melphalan and total body irradiation (TBI) or melphalan alone in the PBSCT group. The alloBMT group received one of four regimens: cyclophosphamide and TBI; cyclophosphamide, VP-16 and 1,3-bis(2-chloroethyl)-1-nitrosourea (CVB); busulfan and cyclophosphamide (BU/CY) and total marrow irradiation (TMI); or melphalan and TBI. Procedure-related mortality was 12.5% for the PBSCT group and 25% for the alloBMT group. With a median follow-up for survivors in the PBSCT and alloBMT groups of 11 months (range, 4-46) and 15 months (range, 2-84 months), respectively, there was no significant difference in median overall survival (33.5 versus 38.6 months, p = 0.7637) or event-free survival (16.7 versus 31 months, p = 0.8450). There was, however, a plateau in survival at 40% in the alloBMT group. No plateau in survival was seen in the PBSCT group. Clinical relapses occurred as late as 39 months posttransplant. Patients have survived up to 28 months postrelapse.

[Research on effects of taurine on the transplanted tumor of mice]

With the same forage to the mice, three experiments were done. The control group took water and experimental group took 1% taurine. 1. After the mice were vaccinated with S180 sarcoma, every group was further divided into two groups, one treated with cytoxan (CTX), another one treated with nothing. The survival period, weight of the tumor and the tumor inhibition rate were investigated. The result shows: The survival period of the group fed with taurine was (35.75 +/- 23.7) days longer than that of the control group (18.7 +/- 5.6) days, and the tumor inhibition rate was 42.26%. The mice fed with taurine and treated with CTX survived to 61 days with no death, and no tumor could be seen grossly, so the tumor inhibition rate is 100%. The survival period and weight of the tumor were not different between the CTX treated and control groups. 2. Tumor cell membrane fluidity was observed after the mice were vaccinated with Erlish ascitic tumor. The result shows: in the taurine group, the fluorescence polarization (p) is 0.108 +/- 0.020, the viscosity (eta) is 0.618 +/- 0.140 and in the control group p is 0.139 +/- 0.20, eta is 0.874 +/- 0.150, respectively. Thus the cell membrane fluidity of the taurine group is also obviously better than that of the control group (P < 0.01). 3. The immune functions of the two groups were determined by carbon clearance test and capacity of serum hemolysin. The immune function of the taurine group is also obviously higher than that of control group (P < 0.01). All the results described above show:taurine is functioning for tumor inhibition, and has obvious synergic effect while treated with CTX as chemotherophy. It is considered that the tumor inhibit function of taurine may be related to its effects of immune enhancing and membrane profecting.

The clinical significance of p21(WAF1/CIP-1) and p53 expression in pancreatic adenocarcinoma

BACKGROUND

Wild-type p53 protein activates the WAF1/CIP-1 (p21) gene, leading to G1 arrest after DNA damage. The authors investigated the relation of p21 and p53 expression in pancreatic adenocarcinomas to disease stage, overall patient survival, and survival when chemotherapy or radiation therapy was given.

METHODS

Paraffin embedded tissue sections of 75 ductal adenocarcinomas of the pancreas were immunostained for p53 and p21. Nuclear expression was scored as absent, focal (<10%), moderate (10-50%), or strong or diffuse (>50%).

RESULTS

The median survival of patients whose pancreatic tumors expressed the p21 protein (43 of 75 cases, 57%) was better than that for patients whose tumors were p21 negative (32 of 75 cases, 43%) (median survival, 13.5 vs. 9.8 months, respectively; P = 0.23). No difference in survival was found with regard to p53 protein expression (43 of 75 cases, 57%); however, strong p53 expression was significantly associated with advanced disease stage (70% in Stage IV vs. 13-28% in lower stages). Expression of p21 correlated with earlier clinical stage. Stage specific comparisons showed a trend toward increased survival among p21 positive tumor patients diagnosed at clinical Stages I and III but not among those diagnosed at Stage IV. Adjuvant chemotherapy or radiation improved survival significantly if tumors expressed p21 or no p53.

CONCLUSIONS

Expression of p21 is significantly associated with earlier clinical stage in pancreatic adenocarcinoma, perhaps accounting for the better survival observed in this patient group than among those whose tumors were p21 negative. Improved survival with either chemotherapy or radiation therapy was observed for patients whose tumors were p21 positive or p53 negative.

The clinical significance of p21(WAF1/CIP-1) and p53 expression in pancreatic adenocarcinoma

BACKGROUND

Wild-type p53 protein activates the WAF1/CIP-1 (p21) gene, leading to G1 arrest after DNA damage. The authors investigated the relation of p21 and p53 expression in pancreatic adenocarcinomas to disease stage, overall patient survival, and survival when chemotherapy or radiation therapy was given.

METHODS

Paraffin embedded tissue sections of 75 ductal adenocarcinomas of the pancreas were immunostained for p53 and p21. Nuclear expression was scored as absent, focal (<10%), moderate (10-50%), or strong or diffuse (>50%).

RESULTS

The median survival of patients whose pancreatic tumors expressed the p21 protein (43 of 75 cases, 57%) was better than that for patients whose tumors were p21 negative (32 of 75 cases, 43%) (median survival, 13.5 vs. 9.8 months, respectively; P = 0.23). No difference in survival was found with regard to p53 protein expression (43 of 75 cases, 57%); however, strong p53 expression was significantly associated with advanced disease stage (70% in Stage IV vs. 13-28% in lower stages). Expression of p21 correlated with earlier clinical stage. Stage specific comparisons showed a trend toward increased survival among p21 positive tumor patients diagnosed at clinical Stages I and III but not among those diagnosed at Stage IV. Adjuvant chemotherapy or radiation improved survival significantly if tumors expressed p21 or no p53.

CONCLUSIONS

Expression of p21 is significantly associated with earlier clinical stage in pancreatic adenocarcinoma, perhaps accounting for the better survival observed in this patient group than among those whose tumors were p21 negative. Improved survival with either chemotherapy or radiation therapy was observed for patients whose tumors were p21 positive or p53 negative.

[Synthesis and degradation of type IV collagen in rat experimental liver fibrosis]

OBJECTIVE

To investigate the synthesis and degradation of type IV collagen in CCl4-induced SD rat liver fibrosis.

METHODS

Dynamic changes and relationships among the tissue alpha 1 (IV) procollagen mRNA, type IV collagen (Col IV) and serum 7S polypeptide fragment of Col IV in fibrotic livers induced by CCl4 with choline difficiency diet were studied using immunohistochemistry, Northern analysis, in situ hybridization and serum RIA techniques.

RESULTS

The transcription of alpha 1 (IV) procollagen mRNA in fibrotic liver and the content of serum 7S polypeptide fragment derived from tissue Col IV degradation was enhanced promptly and obviously in earlier stage of experiment, but not synchronous afterwards. In the early stage of experiment, alpha 1 (IV) procollagen mRNA transcripts was localized in sinusoid Ito cells and endothelial cells. In the mid and late stage, alpha 1 (IV) procollagen mRNA transcripts was localized in myofibroblasts (MFs), fibroblasts (Fbs) and endothelia of small blood vessels in fibrotic septa.

CONCLUSIONS

The change of serum 7S polypeptide fragment could reflect the motabolic state of Col IV and the degree of tissue injury in fibrogenesis and might have some clinical significance in identifying the activiation of the liver fibrosis. The "Ito cell-myofibroblast-fibroblast" effective cell system and sinusoid endothelia were the Col IV producing cells during fibrogenesis, in which sinusoid endothelia, as another source of Col IV production, participated in the capillization of liver sinusoids.

Prenylation of RhoB is required for its cell transforming function but not its ability to activate serum response element-dependent transcription

Rho regulates cytoskeletal actin structure and integrin-mediated cell adhesion. Rho also has a role in cell growth regulation and is required for cell transformation by oncogenic Ras. Recently, it has been demonstrated that Rho can activate transcription from the c-fos serum response element (SRE). This raised the possibility that functions required for Rho-mediated cell transformation might overlap with those involved in transcriptional regulation. Here we show that RhoB can activate the SRE and can synergize in cell transformation with constitutively activated Raf-CAAX. Significantly, unprenylated forms of RhoB that are biologically inert and unable to transform cells can still activate SRE-dependent transcription. This finding suggests that transcriptional activation by Rho may be separable from its cell transforming functions.

Relationship of family cancer history to the expression of p53, p21WAF-1, HER-2/neu, and K-ras mutation in pancreatic adenocarcinoma

CONCLUSION

In our series of 81 cases, a history of family cancer was present in 52% of patients (42/81) with pancreatic cancer. Nine percent (7/81)had a family history of pancreatic cancer. Our studies suggest a possible relationship of family cancer history to the expression of p53 and p21WAF in pancreatic tumors, but show no relationship to the expression of HER-2/neu or to the prevalence of K-ras mutations. A lower incidence of p53 expression observed in patients with a family history of cancer suggests normal p53 protein is present in a majority of patients who develop pancreatic tumors related to other--as yet unidentified-inherited or familial risk factors. There was no significant difference in survival of pancreas cancer patients with and without a family history of cancer. However, survival in pancreas cancer patients may be influenced (improved) by p21WAF-1 expression.

BACKGROUND

Pancreas cancer is the fifth leading cause of cancer deaths (27,800 deaths/yr) in the United States. Various risk factors, including cigarette smoking, high-fat diet, DDT exposure, chronic pancreatitis, and diabetes mellitus, have been associated with pancreatic carcinoma. A few studies have suggested a genetic predisposition or increased risk for pancreatic cancer within families, but the exact etiology is largely unknown. In a series of 81 patients with pancreatic carcinoma, we analyzed the status of K-ras gene mutations and the expression of P21WAF-1, p53, and HER-2/neu protein to identify possible molecular associations in pancreas cancer cases of these molecular markers to family histories of cancer and pancreas cancer.

METHODS

Paraffin-embedded tissue sections from 81 cases of pancreatic adenocarcinoma were used for DNA extraction and immunohistochemical staining. K-ras mutation was studied by single-stranded conformation polymorphism (SSCP) and slot-blot allele-specific oligonucleotide (ASO) hybridization of PCR-amplified DNA product. Overexpression (aberrant expression) of p53, p21WAF-1, and HER-2/neu was documented by scoring nuclear localized p53, p21WAF-1 protein and cell membrane expression of HER-2/neu after immunostaining with gene product-specific monoclonal antibodies (MAbs).

RESULTS

Forty-two (42) of 81 patients studied in this series had a history of cancer in their families (52%). Seven of those 42 had a history of pancreatic carcinoma (17% or 9% of total cases). The incidence of K-ras mutation and the expression of p21WAF-1 and HER-2/neu in patient groups with and without a family history of cancer was not statistically different (83 vs 74%, p = 0.416; 57 vs 41%, p = 0.184; and 83 vs 81%, p = 1.000, respectively). However, the incidence of p53 expression was significantly lower in patients with a family history of cancer (40 vs 72%, p = 0.007). There was no statistical difference in survival of patients with a family history of cancer in relation to either K-ras mutation, p53 expression, p21, or HER-2/neu expression. However, patients lacking a family history of cancer showed improved survival trends in relation to p21 expression (median survival of 16 vs 8 mo, p = 0.029).

[Effect of processing on reducing the toxicity in sulfur]

The content of arsenic in sulfur before and after processing was determined. The result shows that the content in raw materials is 8-15 times higher than that of the processed product, which implies that the toxicity of sulfur is obviously reduced by processing.

Prevalence and clinical significance of combined K-ras mutation and p53 aberration in pancreatic adenocarcinoma

CONCLUSION

This study could not attribute survival differences to the coincident acquisition of two common genetic alterations, K-ras mutation and p53 overexpression in pancreatic adenocarcinoma patients. Additionally, our data indicate the converse to be true: Those patients lacking both K-ras mutation and aberrant p53 expression showed the shortest survival when compared with cases showing either alteration or both. This study also showed the negative effect of K-ras mutation and p53 expression on pancreas cancer patients' survival after treatment with either radiation therapy or chemotherapy.

BACKGROUND

Mutations of the oncogene K-ras at codon 12 are reported to be the most common genetic alteration in pancreatic carcinoma, whereas either overexpression or mutation of the tumor suppressor p53 gene is considered the most common genetic alteration in neoplasia of all types. p53 overexpression has been attributed to survival differences in pancreatic carcinoma, but such association is still controversial. No studies have fully documented the combined incidence of K-ras and p53 alterations in pancreatic adenocarcinoma, or their combined effect on patient survival in a large case series. The influence of radiation or chemotherapy in groups showing both, either, or neither mutation is also undocumented.

METHODS

Paraffin-embedded tissue sections from 76 cases of pancreatic adenocarcinoma were cut for DNA extraction for K-ras analysis and immunohistochemical staining for aberrant p53 expression. K-ras mutation was determined by single-strand conformation polymorphism (SSCP) and slot-blot allele-specific oligonucleotide (ASO) hybridization of PCR-amplified DNA product p53 expression was scored on the basis of percent nuclear staining with the MAb DO7.

RESULTS

Sixty-four of 76 cases (84%) showed K-ras mutation, p53 expression, or both, K-ras was mutated in 55 of 76 cases (72%). p53 was expressed in 33 of 76 cases (43%). Twenty-four of 76 cases (31%) showed both K-ras mutation and p53 expression. The presence of both alterations was not related to significant differences in tumor grade, stage, or survival compared to either alteration alone. A sizable subset (16% of cases) lacked either alteration, and surprisingly, this group showed the shortest median survival compared to those with K-ras mutation, p53 expression, or both (p = 0.024). Patients whose tumors were K-ras-negative showed the greatest difference in median survival with radiation therapy (median survival 30.8 mo vs 7.8 mo with no radiation, p = 0.005).

HER-2/neu expression in pancreatic adenocarcinoma: relation to tumor differentiation and survival

HER-2/neu expression in pancreatic adenocarcinoma has been inconsistently reported and has not been fully evaluated with respect to histologic grade and tumor grade heterogeneity. We studied HER-2/neu expression in a series of 79 primary pancreatic carcinomas using immunohistochemical methods, with expression scored for each histologic grade represented in each tumor. We found significantly lower expression of HER-2/neu in poorly differentiated (PD) portions of tumors-those areas lacking glandular differentiation-compared to well-differentiated (WD) and moderately differentiated (MD) portions of tumors. Forty-two of 68 (62%) invasive tumors with WD or MD glands showed moderate or strong expression of HER-2/neu in WD/MD areas; only 6 of 32 (19%) invasive tumors with PD areas showed similar expression in PD. In mutually exclusive patient sets, we also found a statistically different prevalence of HER-2/neu expression in patients with PD (6/32 cases; 19%) and without PD (29/47 cases; 62%) tumors (p < 0.001). Twenty-three cases had directly comparable areas of PD versus MD or WD. In 19 of 23 cases HER-2/neu expression was graded comparatively lower (or negative) in areas of PD than in MD or WD. Overall 46 of 79 cases (58%) showed moderate to strong HER-2/neu expression inclusive of all histologic grades, and 63 of 79 (80%) cases were HER-2/neu positive, if including weak or focal staining. There was no significant difference in the survival of patients with HER-2/neu-positive versus-negative tumors or in patients with versus without PD tumors. We have confirmed that although HER-2/neu gene expression is common to many pancreatic carcinomas, it is not common to tumors lacking glandular differentiation. HER-2/neu gene expression could not be related to survival differences--perhaps due to overall poor survival within adenocarcinomas of the pancreas--but the pattern of HER-2/neu expression suggests a relationship to glandular differentiation and early oncogenesis.

[A study on type I, III and IV collagen production in CCl4 induced rat liver fibrosis]

OBJECTIVE

To study the dynamic changes of alpha 1 (I), alpha 1 (III) and alpha I (IV) procollagen mRNA and collagen-producing cells during CCl4 induced SD rat liver fibrogenesis (20 weeks).

METHODS

The investigations were performed using Northern blot analysis, in situ hybridization and immunohistochemical techniques.

RESULTS

The increased expression of alpha 1 (III) procollagen mRNA during fibrogenesis by Northern blot analysis was the most predominant among the three mRNAs studied. However, the increase of alpha 1 (IV) procollagen mRNA expression occurred earlier, while the expression of alpha 1 (I) mRNA did not increase until the middle stage of the experiment. Desmin positive and/or smooth muscle actin positive Ito cells and myofibroblasts (MFs) in and around the necrotic areas expressed alpha 1 (I), alpha 1 (III) and alpha 1 (IV) procollagen mRNA signals detected by in situ hybridization during the early stage of the experiment. All the three procollagen mRNAs were mostly localized in fibroblasts (Fbs) and MFs in the septa during the mid and late stages of fibrosis.

CONCLUSIONS

Fbs and MFs were considered as important Col I, Col III and Col IV producing cells in liver fibrosis. Sinusoid endothelia were involved in Col IV synthesis in the fibrotic liver.

Effect of pressure ulcers on the survival of long-term care residents

BACKGROUND

Past studies have emphasized that patients with pressure ulcers are at high risk of dying. However, it remains unclear whether this increased risk is related to the ulcer or to coexisting conditions. In this study we examined the independent effect of pressure ulcers on the survival of long-term care residents.

METHODS

We evaluated all 19,981 long-term care residents institutionalized in Department of Veterans Affairs (VA) long-term care facilities as of April 1, 1993. Baseline resident characteristics and survival status were obtained by merging data from five existing VA data bases. Survival experience over a 6-month period was described using a proportional hazards model.

RESULTS

Pressure ulcers were present in 1,539 (7.7%) long-term care residents. Residents with pressure ulcers had a relative risk of 2.37 (95% CI = 2.13, 2.64) for dying as compared to those without ulcers. After adjusting for 16 other measures of clinical and functional status, the relative risk associated with pressure ulcers decreased to 1.45 (95% CI = 1.30, 1.65). No increased risk of death was noted for residents with deeper ulcers.

CONCLUSIONS

Pressure ulcers are a significant marker for long-term care residents at risk of dying. After adjusting for clinical and functional status, however, the independent risk associated with pressure ulcers declines considerably. The fact that larger ulcers are not associated with greater risk suggests that other unmeasured clinical conditions may also be contributing to the increased mortality associated with pressure ulcers.

Strain activation of bovine aortic smooth muscle cell proliferation and alignment: study of strain dependency and the role of protein kinase A and C signaling pathways

Smooth muscle cell (SMC) phenotype can be altered by physical forces as demonstrated by cyclic strain-induced changes in proliferation, orientation, and secretion of macromolecules. However, the magnitude of strain required and the intracellular coupling pathways remain ill defined. To examine the strain requirements for SMC proliferation, we selectively seeded bovine aortic SMC either on the center or periphery of silastic membranes which were deformed with 150 mm Hg vacuum (0-7% center; 7-24% periphery). SMC located in either the center or peripheral regions showed enhanced proliferation compared to cells grown under the absence of cyclic strain. Moreover, SMC located in the center region demonstrated significantly (P < 0.005) greater proliferation as compared to those in the periphery. In contrast, SMC exposed to high strain (7-24%) demonstrated alignment perpendicular to the strain gradient, whereas SMC in the center (0-7%) remained aligned randomly. To determine the mechanisms of these phenomena, we examined the effect of cyclic strain on bovine aortic SMC signaling pathways. We observed strain-induced stimulation of the cyclic AMP pathway including adenylate cyclase activity and cyclic AMP accumulation. In addition, exposure of SMC to cyclic strain caused a significant increase in protein kinase C (PKC) activity and enzyme translocation from the cytosol to a particulate fraction. Further study was conducted to examine the effect of strain magnitude on signaling, particularly protein kinase A (PKA) activity as well as cAMP response element (CRE) binding protein levels. We observed significantly (P < 0.05) greater PKA activity and CRE binding protein levels in SMC located in the center as compared to the peripheral region. However, inhibition of PKA (with 10 microM Rp-cAMP) or PKC (with 5-20 ng/ml staurosporine) failed to alter either the strain-induced increase in SMC proliferation or alignment. These data characterize the strain determinants for activation of SMC proliferation and alignment. Although strain activated both the AC/cAMP/PKA and the PKC pathways in SMC, singular inhibition of PKA and PKC failed to prevent strain-induced alignment and proliferation, suggesting either their lack of involvement or the multifactorial nature of these responses.

Activation of the adenylyl cyclase/cyclic AMP/protein kinase A pathway in endothelial cells exposed to cyclic strain

The aim of this study was to assess the involvement of the adenylyl cyclase/cyclic AMP/protein kinase A pathway (AC) in endothelial cells (EC) exposed to different levels of mechanical strain. Bovine aortic EC were seeded to confluence on flexible membrane-bottom wells. The membranes were deformed with either 150 mm Hg (average 10% strain) or 37.5 mm Hg (average 6% strain) vacuum at 60 cycles per minute (0.5 s strain; 0.5 s relaxation) for 0-60 min. The results demonstrate that at 10% average strain (but not 6% average strain) there was a 1.5- to 2.2-fold increase in AC, cAMP, and PKA activity by 15 min when compared to unstretched controls. Further studies revealed an increase in cAMP response element binding protein in EC subjected to the 10% average strain (but not 6% average strain). These data support the hypothesis that cyclic strain activates the AC/cAMP/PKA signal transduction pathway in EC which may occur by exceeding a strain threshold and suggest that cyclic strain may stimulate the expression of genes containing cAMP-responsive promoter elements.

Activation of diacylglycerol in cultured endothelial cells exposed to cyclic strain

Confluent bovine aortic endothelial cells (EC) were grown on flexible membranes and subjected to 10% average strain at 60 cycles/min for up to 500 s. A biphasic increase in diacylglycerol (DAG) occurred, with an initial transient peak at 10 s followed by sustained elevation to 500 s. The early peak corresponded to the transient formation of inositol 1,4,5-trisphosphate, demonstrating hydrolysis of L-alpha-phosphatidylinositol (PI) by PI-specific phospholipase C. To determine the origin of the sustained DAG phase, we incubated confluent bovine aortic EC with 1 microCi/ml [14C]myristate overnight and subjected them to cyclic strain. There was a decrease in phosphatidylcholine (PC) and a corresponding increase in DAG at 10 s and 250 s, suggesting PC hydrolysis with the generation of DAG at both an early (10 s) and a late (250 s) phase. [14C]phosphatidylethanol, a specific product of phospholipase D (PLD) in the presence of 1% ethanol, was measured in EC preincubated with [14C]myristate. Cyclic strain led to an immediate and sustained activation of PLD. Increased ethanol concentration led to a consistent decrease in DAG. Furthermore, when EC were pretreated with 1% ethanol, the strain-induced proliferative response was attenuated.

Harmaline-induced tremor and impairment of learning are both blocked by dizocilpine in the rabbit

Harmaline is known to produce tremors and retard acquisition of the rabbit's nictitating membrane response. These actions have been demonstrated to depend on the ability of harmaline to activate the inferior olive which gives rise to climbing fibers that project directly onto Purkinje cells in cerebellar cortex. However, the precise receptor systems involved in harmaline's actions remains unknown. This study examined the role of the NMDA receptor in harmaline's actions. Harmaline (10 mg/kg, s.c.) produced intense tremors and impaired the acquisition of conditioned responses. Both of these effects of harmaline were significantly blocked by the prior administration of the noncompetitive NMDA channel blocker, dizocilpine (0.01 mg/kg, s.c. given 20 min prior to the administration of harmaline). This dose od dizocilpine had no effect on acquisition of conditioned responses when given alone. A higher dose of dizocilpine (0.1 mg/kg s.c.) completely blocked the tremorogenic effects of harmaline (10 mg/kg, s.c.). Dizocilpine had no effect on motor behavior when given alone. It was suggested that the blockade of harmaline's actions by dizocilpine may be occurring at NMDA channels within the inferior olive. Regardless of the site of action, these data demonstrate that harmaline's ability to activate the interior olivary nucleus depends on the normal activity of the NMDA receptor.

Gene regulation by mechanical forces

Endothelial cells are subjected to various mechanical forces in vivo from the flow of blood across the luminal surface of the blood vessel. The purpose of this review was to examine the data available on how these mechanical forces, in particular cyclic strain, affect the expression and regulation of endothelial cell function. Studies from various investigators using models of cyclic strain in vitro have shown that various vasoactive mediators such as nitric oxide and prostacyclin are induced by the effect of mechanical deformation, and that the expression of these mediators may be regulated at the transcription level by mechanical forces. There also seems to be emerging evidence that endothelial cells may also act as mechanotransducers, whereby the transmission of external forces induces various cytoskeletal changes and second messenger cascades. Furthermore, it seems these forces may act on specific response elements of promoter genes.

The nitric oxide synthesis inhibitor L-NAME facilitates associative learning

1. Nitric oxide has been suggested to play an important role in synaptic plasticity and in learning. 2. The authors examined the effects of NW-nitro-L-arginine methyl ester, a competitive and enantiomeric specific inhibitor of nitric oxide synthase, on classical conditioning of the rabbit's nictitating membrane response. 3. It was found that L-NAME significantly enhanced the acquisition of conditioned responses. 4. The enhanced conditioned responses were not due to a sensitization of the conditioned and unconditioned reflexes or to changes in baseline levels of responding. 5. The dose and route of administration of L-NAME employed in this study had no effect on blood pressure. 6. These results suggest that nitric oxide normally functions as a tonic inhibitory modulator of associative learning and that procedures aimed at decreasing its production may provide a novel approach for improving learning.

Isolation and sequence of the Drosophila virilis 60 A gene, a transforming growth factor-beta superfamily member related to vertebrate bone morphogenetic proteins

The complete protein-coding region of the Drosophila virilis 60 A gene, a member of the transforming growth factor-beta superfamily, was isolated and sequenced. The mature domain of the protein-coding region is 99% identical to the Drosophila melanogaster 60 A gene and 73% identical to human bone morphogenetic protein 5. In the pro-domain, a number of large blocks of amino acids are also highly conserved, indicating an important functional role for this portion of the protein as well. In the putative 5' and 3' untranslated regions, several short sequence motifs are conserved between D. virilis and D. melanogaster.

Ectopic expression of dE2F and dDP induces cell proliferation and death in the Drosophila eye

The deregulation of E2F activity is thought to contribute to the uncontrolled proliferation of many tumor cells. While the effects of overexpressing E2F genes have been studied extensively in tissue culture, the consequences of elevating E2F activity in vivo are unknown. To address this issue, transgenic lines of Drosophila were studied in which ectopic expression of dE2F and dDP was targeted to the developing eye. The co-expression of dDP or dE2F disrupted normal eye development, resulting in abnormal patterns of bristles, cone cells and photoreceptors. dE2F/dDP expression caused ectopic S phases in post-mitotic cells of the eye imaginal disc but did not disrupt the onset of neuronal differentiation. Most S phases were seen in uncommitted cells, although some cells that had initiated photo-receptor differentiation were also driven into the cell cycle. Elevated expression of dE2F and dDP caused apoptosis in the eye disc. The co-expression of baculovirus p35 protein, an inhibitor of cell death, strongly enhanced the dE2F/dDP-dependent phenotype. These results show that, in this in vivo system, the elevation of E2F activity caused post-mitotic cells to enter the cell cycle. However, these cells failed to proliferate unless rescued from apoptosis.

Requirements for dE2F function in proliferating cells and in post-mitotic differentiating cells

The transcription factor E2F is a target of the retinoblastoma tumor suppressor protein (pRB) and may mediate pRB regulation of S phase entry in mammalian cells. The recent identification of mutant alleles of the Drosophila E2F gene (dE2F) has shown that dE2F is required for embryogenesis. dE2F-mutant embryos lack a co-ordinated program of gene expression which accompanies S phase entry and DNA synthesis declines to levels that are barely detectable. We have investigated the role of the dE2F gene at later stages of development. dE2F is expressed in several larval tissues and is required for cell proliferation in the eye imaginal disc. Surprisingly, dE2F expression persists in post-mitotic cells of the eye disc of third-instar larvae. The loss of dE2F function in these cells causes a novel phenotype, characterized by loss of photoreceptors and abnormal rhabdomere cell morphology. These results show that dE2F is required at multiple stages of development and suggest that E2F may have an important function in post-mitotic cells in addition to its role during cell proliferation.