Image analysis of nailfold capillaries in patients with undifferentiated connective tissue syndromes

Several studies have reported patients that show nailfold capillary abnormality without fulfilling any of the criteria for rheumatic diseases. Our objective was to define how many patients with undifferentiated connective tissue syndrome (UCTS) have nailfold capillary abnormalities and to determine the correlation between capillary abnormality and clinical findings. We analyzed videograph images of nailfold capillaries in 75 patients with UCTS, comparing them with 22 normal controls (NL) and 55 patients with systemic sclerosis (SS), using standardized canonical discriminant analysis. Sixty patients with UCTS showed the SS type pattern and 15, the NL type pattern. The SS type pattern in patients with UCTS significantly correlated with Raynaud's phenomenon, telangiectasia, and anti-nuclear antibody. The UCTS patients with nailfold capillary abnormalities correlated with symptoms of SS have a possibility of progressing to SS. The follow up study of these patients will show whether progression to SS occurs.

Phase I study of paclitaxel by three-hour infusion: hypotension just after infusion is one of the major dose-limiting toxicities

The primary objectives of this study were to determine the maximum tolerated dose (MTD) of paclitaxel administered by 3-h infusion to patients with solid tumors, and to characterize the pharmacokinetics of a 3-h infusion in comparison with those of a 24-h infusion. Twenty-seven patients each received one of six levels of paclitaxel, 105, 135, 180, 210, 240 and 270 mg/m2, with premedication. Two patients given 240 mg/m2 and one patient given 270 mg/m2 unexpectedly had grade 3/4 hypotension just after finishing the paclitaxel infusion. Peripheral neuropathy was also dose-limiting at 270 mg/m2. Although granulocytopenia was significantly less severe than with a 24-h infusion, more than half of the patients experienced grade 4 toxicity at doses of 240 or 270 mg/m2. Severe hypersensitivity reactions (HSRs) were not observed. Pharmacokinetic studies using high performance liquid chromatography demonstrated proportionally greater increases in the peak plasma concentration and area under the curve, and decreases in clearance and volume of distribution with increasing dose, suggesting non-linear pharmacokinetics of paclitaxel when given by 3-h infusion. The MTD of paclitaxel given as a 3-h infusion was determined to be 240 mg/m2 with dose-limiting toxicities of granulocytopenia, peripheral neuropathy and hypotension. Hypotension just after infusion, induced by 3-h infusion of paclitaxel, is a new observation which has not been reported previously. The recommended dose for phase II study is 210 mg/m2. Although hypotension was observed as an unexpected toxic effect, paclitaxel could be administered safely over 3 h with premedication and proper monitoring, resulting in reduced myelotoxicity and with no increase in the incidence of HSRs as compared with a 24-h infusion.

Prospective evaluation of the feasibility of cisplatin-based chemotherapy for elderly lung cancer patients with normal organ functions

A study was conducted to examine the feasibility of cisplatin-based chemotherapy in elderly patients (> or = 75 years old) with advanced non-small cell lung cancer (NSCLC) or small cell lung cancer (SCLC). Thirty-four patients were enrolled between September 1993 and December 1994. Patients with normal organ function and good performance status (PS) received cisplatin-based chemotherapy (cisplatin 80 mg/m2 on day 1 and vindesine 3 mg/m2 on days 2 and 8 for NSCLC, or cisplatin 80 mg/m2 on day 1 and etoposide 100 mg/m2 on days 2 to 4 for SCLC). Ten patients (29%) were eligible for this study, 7 with NSCLC and 3 with SCLC. Reasons for exclusion were ischemic heart disease in 14, poor PS (> or = 2) in 11, reduced creatinine clearance (Cer) in 10, abnormal electrocardiogram without ischemia in 9 and noncompliance with the protocol in 2 patients. Eight patients had two or more reasons. Nine of the 10 eligible patients were able to tolerate two or more courses of chemotherapy. All 3 patients with SCLC responded (1 complete response and 2 partial response), but only 1 of the patients with NSCLC achieved partial response. Toxicity was evaluated according to Japan Clinical Oncology Group criteria. All but one patient experienced grade 4 neutropenia, and 6 patients had infectious episodes requiring antibiotics. Grade 3 anemia and thrombocytopenia were observed in 1 and 2 patients, respectively. Non-hematological toxicities were mild. Only 10 of 34 patients (29%) satisfied our eligibility criteria and they experienced severe myelotoxicity. We conclude that chemotherapy should be given carefully to elderly patients even if they appear to have normal organ function.

Induction of Fas-mediated apoptosis in p53-transfected human colon carcinoma cells

To investigate the biological function of p53 in colon carcinoma cells, a wild-type p53 expression plasmid under the control of the human cytomegalovirus promoter was stably transfected into the human colon adenocarcinoma cell line WiDr, which carries a mutation of the p53 gene at codon 273. Exogenous wild-type p53 transcripts were detected at various expression levels in 8 of 117 G418-resistant clones. The growth rates of the wild-type p53+ clones in culture did not change significantly. The efficiency of colony formation in soft agar, however, was completely suppressed in two wild-type p53+ clones. This is the first to demonstrate the feasibility of stable transfection of the wild-type p53 gene under the control of non-inducible promoter in human colon cancer cells. The major alteration found was that wild-type p53+ cells which were incubated with anti-Fas IgM showed marked cytolysis with preferential over-expression of wild-type p53 accompanied by overexpression of a cyclin-dependent kinase inhibitor, WAF1, whereas the endogenous mutant p53 retained its expression level. The findings suggest that a Fas-initiated pathway is incidentally linked to a p53-dependent apoptotic pathway through the reconstituted wild-type p53 gene in WiDr cells. This model should help elucidating the additional role of the p53 tumor suppressor gene and the mechanism of apoptosis in colon carcinoma cells.

Early activation signal transduction pathways of Th1 and Th2 cell clones stimulated with anti-CD3. Roles of protein tyrosine kinases in the signal for IL-2 and IL-4 production

In the present experiments, TCR-CD3-associated early activation signal transduction pathways were examined in Th1 and Th2 clones by the stimulation with soluble monovalent anti-CD3 which resulted in efficient production of IL-2 and IL-4 in Th1 and Th2 cells, respectively. Although protein tyrosine kinases such as Fyn and ZAP-70 were activated in Th1 clones shortly after stimulation, these kinases in Th2 clones were not activated; but, their activity in resting conditions was shown to be decreased by the stimulation. In accordance with these findings, neither phospholipase C-gamma 1 activation nor phosphatidyl inositol-4,5-bisphosphate breakdown was induced in Th2 clones, in contrast to positive responses in Th1 clones. The oscillation of intracellular free Ca2+ concentration ([Ca2+]i) was a common signal for the activation of both Th1 and Th2 clones; however, the [Ca2+]i elevation in Th1 clones was herbimycin A sensitive, whereas that in Th2 was clone resistant, suggesting that the mechanism of the [Ca2+]i elevation in Th2 cells is different from that in Th1 cells in terms of the participation of protein tyrosine kinases. The anti-CD3 stimulation did not cause Lck activation in either the Th1 or Th2 clone, although remarkable activation was induced in both clones following anti-CD4 stimulation, indicating that Lck activation was not required for either IL-2 or IL-4 production of Th cells. Taken together, these results indicate that Th1 and Th2 cells are different from each other in early activation signal transduction pathways, especially in the role of protein tyrosine kinases.

Early activation signal transduction pathways of Th1 and Th2 cell clones stimulated with anti-CD3. Roles of protein tyrosine kinases in the signal for IL-2 and IL-4 production

In the present experiments, TCR-CD3-associated early activation signal transduction pathways were examined in Th1 and Th2 clones by the stimulation with soluble monovalent anti-CD3 which resulted in efficient production of IL-2 and IL-4 in Th1 and Th2 cells, respectively. Although protein tyrosine kinases such as Fyn and ZAP-70 were activated in Th1 clones shortly after stimulation, these kinases in Th2 clones were not activated; but, their activity in resting conditions was shown to be decreased by the stimulation. In accordance with these findings, neither phospholipase C-gamma 1 activation nor phosphatidyl inositol-4,5-bisphosphate breakdown was induced in Th2 clones, in contrast to positive responses in Th1 clones. The oscillation of intracellular free Ca2+ concentration ([Ca2+]i) was a common signal for the activation of both Th1 and Th2 clones; however, the [Ca2+]i elevation in Th1 clones was herbimycin A sensitive, whereas that in Th2 was clone resistant, suggesting that the mechanism of the [Ca2+]i elevation in Th2 cells is different from that in Th1 cells in terms of the participation of protein tyrosine kinases. The anti-CD3 stimulation did not cause Lck activation in either the Th1 or Th2 clone, although remarkable activation was induced in both clones following anti-CD4 stimulation, indicating that Lck activation was not required for either IL-2 or IL-4 production of Th cells. Taken together, these results indicate that Th1 and Th2 cells are different from each other in early activation signal transduction pathways, especially in the role of protein tyrosine kinases.

Characterization of guanylate cyclase activity in single retinal rod outer segments

cGMP mediates vertebrate phototransduction by directly gating cationic channels on the plasma membrane of the photoreceptor outer segment. This second messenger is produced by a guanylate cyclase and hydrolyzed by a light-activated cGMP-phosphodiesterase. Both of these enzyme activities are Ca2+ sensitive, the guanylate cyclase activity being inhibited and the light-activated phosphodiesterase being enhanced by Ca2+. Changes in these activities due to a light-induced decrease in intracellular Ca2+ are involved in the adaptation of photoreceptors to background light. We describe here experiments to characterize the guanylate cyclase activity and its modulation by Ca2+ using a truncated rod outer segment preparation, in order to evaluate the enzyme's role in light adaptation. The outer segment of a tiger salamander rod was drawn into a suction pipette to allow recording of membrane current, and the remainder of the cell was sheared off with a probe to allow internal dialysis. The cGMP-gated channels on the surface membrane were used to monitor conversion of GTP, supplied from the bath, into cGMP by the guanylate cyclase in the outer segment. At nominal 0 Ca2+, the cyclase activity had a Km of 250 microM MgGTP and a Vmax of 25 microM cGMP s-1 in the presence of 1.6 mM free Mg2+; in the presence of 0.5 mM free Mg2+, the Km was 310 microM MgGTP and the Vmax was 17 microM cGMP s-1. The stimulation by Mg2+ had an EC50 of 0.2 mM Mg2+ for MgGTP at 0.5 mM. Ca2+ inhibited the cyclase activity. In a K+ intracellular solution, with 0.5 mM free Mg2+ and 2.0 mM GTP, the cyclase activity was 13 microM cGMP s-1 at nominal 0 Ca2+; Ca2+ decreased this activity with a IC50 of approximately 90 nM and a Hill coefficient of approximately 2.0.

Inhibitory effect of some oxygenated stigmastane-type sterols on 12-O-tetradecanoylphorbol-13-acetate-induced inflammation in mice

The oxygenated stigmastane-type sterols stigmastane-3 beta, 6 alpha-diol, stigmastane-3 beta, 6 beta-diol, 7 alpha-hydroxysitosterol and its diacetyl derivative, 7 beta-hydroxysitosterol and its diacetyl derivative, 7-oxositosterol, 4 beta-hydroxysitosterol, and stigmast-4-ene-3 beta, 6 beta-diol were evaluated with respect to their anti-inflammatory activity against 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation in mice. All of the sterols, with the exception of 7 alpha-hydroxysitosterol and its diacetyl derivative, were found to possess marked inhibitory activity. The 50% inhibitory dose of these compounds for TPA-inflammation (1 microgram) was 0.5--1.0 mg/ear.

Interleukin (IL)-6 induction of osteoclast differentiation depends on IL-6 receptors expressed on osteoblastic cells but not on osteoclast progenitors

We reported that interleukin (IL) 6 alone cannot induce osteoclast formation in cocultures of mouse bone marrow and osteoblastic cells, but soluble IL-6 receptor (IL-6R) strikingly triggered osteoclast formation induced by IL-6. In this study, we examined the mechanism of osteoclast formation by IL-6 and related cytokines through the interaction between osteoblastic cells and osteoclast progenitors. When dexamethasone was added to the cocultures, IL-6 could stimulate osteoclast formation without the help of soluble IL-6R. Osteoblastic cells expressed a very low level of IL-6R mRNA, whereas fresh mouse spleen and bone marrow cells, both of which are considered to be osteoclast progenitors, constitutively expressed relatively high levels of IL-6R mRNA. Treatment of osteoblastic cells with dexamethasone induced a marked increase in the expression of IL-6R mRNA. By immunoblotting with antiphosphotyrosine antibody, IL-6 did not tyrosine-phosphorylate a protein with a molecular mass of 130 kD in osteoblastic cells but did so in dexamethasone-pretreated osteoblastic cells. Osteoblastic cells from transgenic mice constitutively expressing human IL-6R could support osteoclast development in the presence of human IL-6 alone in cocultures with normal spleen cells. In contrast, osteoclast progenitors in spleen cells from transgenic mice overexpressing human IL-6R were not able to differentiate into osteoclasts in response to IL-6 in cocultures with normal osteoblastic cells. These results clearly indicate that the ability of IL-6 to induce osteoclast differentiation depends on signal transduction mediated by IL-6R expressed on osteoblastic cells but not on osteoclast progenitors.

Intensive chemotherapy with cisplatin, doxorubicin, cyclophosphamide, etoposide and granulocyte colony-stimulating factor for advanced thymoma or thymic cancer: preliminary results

A study was conducted to evaluate the impact of cisplatin, doxorubicin, cyclophosphamide and etoposide (PACE) with granulocyte colony-stimulating factor (G-CSF) on advanced thymoma or thymic cancer. Between August 1989 and December 1994, 14 patients with invasive, metastatic or recurrent thymoma or thymic cancer were treated with cisplatin (80 mg/m2, on day 1), doxorubicin (45 mg/m2, on day 1), cyclophosphamide (800 mg/m2, on day 1) and etoposide (80 mg/m2, on day 1-3) with G-CSF (90 micrograms/m2, on day 5-18) at the National Cancer Center Hospital, Tokyo. Courses were repeated every 3 or 4 weeks for a maximum of 4 cycles. Twelve patients were treated with 2 or more courses of PACE. Two patients were treated with only one course, one refused and another required emergency thoracic radiotherapy after one course of PACE. Six patients had partial responses (3 thymomas and 3 thymic cancers) but there were no complete remissions (response rates, 42.9%; 95% confidence interval, 17.7% to 71.1%). Moderate hematological toxicities were observed: grade 3 or 4 leukopenia, neutropenia, anemia and thrombocytopenia in 10, 13, 8 and 6 patients, respectively. Six patients developed infections that required antibiotics. Surgical resection or thoracic radiotherapy after PACE treatment was performed in 2 and 7 patients, respectively. The overall median survival time was 14.7 months (range, 5.9 to 59.7 months). For 9 patients who had received no prior treatment before chemotherapy, the median survival time was 8.9 months, and one patient survived for 4 years and is still alive. In conclusion, PACE with G-CSF frequently produces objective remissions in patients with advanced thymoma or thymic cancer. A large-scale intergroup study is necessary to determine the impact of this regimen on advanced thymoma and thymic cancer.

Intracoronary stenting of a coronary occlusion resulting from an aortic dissection

Acute myocardial infarction secondary to aortic dissection may occur due to compression of the coronary arteries by a hematoma or extension of the dissection into the coronary arterial wall. We report a patient with this condition who was successfully treated by Palmaz-Schatz stenting, providing an alternative to thrombolysis or angioplasty.

Induction of anti-tumor immunity by mouse tumor cells transfected with mouse interleukin-12 gene

Interleukin-12 (IL-12) is a heterodimeric cytokine. In order to transduce both cDNAs for p35 and p40 of IL-12 in the tumor cells, a polycistronic retroviral vector was constructed by inserting the internal ribosome entry site gene of encephalomyocarditis virus between two cDNAs. On the other hand, two cDNAs were sequentially transfected in the tumor cells. Both polycistronic gene transfectants and double transfectants produced biologically active mouse IL-12. IL-12-expressing tumor cells were all rejected in syngeneic mice, and induced cytotoxic T lymphocyte activity. The capacity to induce anti-tumor memory may depend on the amount of IL-12 produced by the transfectants, because the relatively higher IL-12 producer tumor cell line induced the anti-tumor memory in the rejected mice, but the lower producer did not.

Degradation of c-Fos by the 26S proteasome is accelerated by c-Jun and multiple protein kinases

c-Fos is associated with c-Jun to increase the transcription of a number of target genes and is a nuclear proto-oncoprotein with a very short half-life. This instability of c-Fos may be important in regulation of the normal cell cycle. Here we report a mechanism for degradation of c-Fos. Coexpression of c-Fos and c-Jun in HeLa cells caused marked increase in the instability of c-Fos, whereas v-Fos, the retroviral counterpart of c-Fos, was stable irrespective of the coexpression of c-Jun. Interestingly, deletion of the C-terminal PEST region of c-Fos, which is altered in v-Fos by a frameshift mutation, greatly enhanced its stability, with loss of the effect of c-Jun on its stability. c-Fos synthesized in vitro was degraded by the 26S proteasome in a ubiquitin-dependent fashion. Simple association with c-Jun had no effect on the degradation of c-Fos, but the additions of three protein kinases, mitogen-activated protein kinase, casein kinase II, and CDC2 kinase, resulted in marked acceleration of its degradation by the proteasome-ubiquitin system, though only in the presence of c-Jun. In contrast, v-Fos and c-Fos with a truncated PEST motif were not degraded, suggesting that they escaped from down-regulation by breakdown. These findings indicate a new oncogenic pathway induced by acquisition of intracellular stability of a cell cycle modulatory factor.

Image analysis of nail fold capillaries in patients with Raynaud's phenomenon

Videograph images of nail fold capillaries in patients with Raynaud's phenomenon were analyzed, and capillary patterns were defined using standardized canonical discriminant analysis. Of sixty-eight patients with Raynaud's phenomenon, forty-nine (72 percent) showed a systemic sclerosis pattern and nineteen (28 percent) showed a normal pattern. The systemic sclerosis type capillary pattern significantly correlated not only with secondary Raynaud's syndrome but also with sclerodactyly, telangiectasia, and antinuclear antibody. This study confirms the value of nail fold capillary microscopy as a noninvasive technique for the examination of the cutaneous microcirculation in vivo. We should continue to evaluate the patients with Raynaud's phenomenon who showed systemic sclerosis pattern abnormality to determine if these patients would show a progression to systemic sclerosis or not.

Tyrosine 807 of the v-Fms oncogene product controls cell morphology and association with p120RasGAP

Expression of the v-fms oncogene of feline sarcoma virus in fibroblasts causes surface exposure of an activated receptor tyrosine kinase, v-Fms, that is autophosphorylated at multiple sites within its cytoplasmic domain. Cellular proteins interacting with this part of v-Fms modulate the mitogenic activity and morphology of the cells. We show here that the tyrosine residue in position 807 (Y-807) of the v-Fms molecule constitutes a major autophosphorylation site. The replacement of this residue by phenylalanine (Y807F mutation) allowed us to functionally dissect v-Fms-specific mitogenic and morphogenic cascades. Cells expressing the mutant v-Fms molecule resembled wild-type (wt) v-Fms-transformed (wt-v-Fms) cells in terms of [3H]thymidine uptake rates and activation of the Ras/Raf-1 mitogenic cascade. Such cells showed, however, a flat morphology and contained intact actin cables and fibronectin network. Our studies indicate that the v-Fms molecule controls cell morphology by a cascade that involves a direct interaction with p120RasGAP and p190RhoGAP: (i) in contrast to wt v-Fms molecules, the Y807F v-Fms protein failed to associate with and phosphorylate p120RasGAP; (ii) tight complexes between p120RasGAP and p190RhoGAP as well as detectable RhoGAP activity were present exclusively in wt-v-Fms cells; and (iii) p190RhoGAP was dispersed throughout the cytoplasm of wt-v-Fms cells, whereas its distribution was restricted to perinuclear regions of cells expressing the mutant v-Fms gene.

Growth inhibition of Ureaplasma urealyticum by the proton pump inhibitor lansoprazole: direct attribution to inhibition by lansoprazole of urease activity and urea-induced ATP synthesis in U. urealyticum

The proton pump inhibitors (PPIs) omeprazole and lansoprazole and the acid-activated analog of lansoprazole AG-2000, which potently inhibit the urease of Helicobacter pylori (K. Nagata, H. Satoh, T. Iwahi, T. Shimoyama, and T. Tamura, Antimicrob. Agents Chemother. 37:769-774, 1993), also inhibited the urease activities of cell-free extracts as well as intact cells of Ureaplasma urealyticum. The 50% inhibitory concentrations were between 1 and 25 microM. These compounds also inhibited the ATP synthesis induced by urea in ureaplasma cells. The 50% inhibitory concentrations for ATP synthesis were close to those for urease activity, but they were lower than those of urease inhibitors, such as acetohydroxamic acid, hydroxyurea, and thiourea. In addition, one of the metabolites of lansoprazole found in human urine, M-VI, also inhibited ureaplasmal urease activity and the ATP synthesis induced by urea at almost the same concentrations as those of lansoprazole. The inhibition of PPIs against ureaplasma urease was very similar to those against H. pylori urease, suggesting that the inhibitory mechanism against these ureases was due to the blockage of the SH residues on the cysteine of the enzyme. Omeprazole, lansoprazole, AG-2000, and M-VI inhibited the growth of U. urealyticum. Since ureaplasma urease is thought to be involved in the pathogenicity of this organism in the urogenital tract, PPIs and their analogs may be useful as chemotherapeutic agents against diseases caused by U. urealyticum.

Synthesis and structure-activity studies of a series of 1-oxa-2,8-diazaspiro[4.5]decan-3-ones and related compounds as M1 muscarinic agonists

A series of novel 2,8-dialkyl-1-oxa-2,8-diazaspiro[4.5]decan-3-ones and 2,8-dimethyl-1,2,8-triazaspiro[4.5]-decan-3-one (13), related to M1 muscarinic agonists YM796 and RS86, were synthesized by using Michael addition reaction of hydroxyurea or methylhydrazine to alpha, beta-unsaturated esters followed by cyclization reaction. These compounds were assessed for binding affinities for M1 and M2 receptors and in vivo muscarinic activity: namely, amelioration of scopolamine-induced impairment in rat passive avoidance tasks and induction of hypothermia, tremor, and salivation. 2,8-Dimethyl-1-oxa-2,8-diazaspiro[4.5]decan-3-one (6a) exhibited high affinities for both M1 and M2 receptors, showed antiamnesic activity (0.1 mg/kg, s.c.) and induced hypothermia (3 mg/kg, s.c.). In addition, 6a stimulated phosphoinositide hydrolysis in rat hippocampal slices, indicating partial agonistic activity for M1 muscarinic receptors. The alteration of the methyl group at N2 of 6a increased the selectivity in binding affinities for M1 over M2 receptors, but resulted in loss of M1 agonistic activity or antiamnesic activity. Compound 13 exhibited only low affinity for M1 receptors, suggesting that a basic nitrogen atom is not tolerated in M1 receptor binding as a substitute for an oxygen atom or a carbonyl group at the 1-position of 6a or RS86. None of these derivatives exhibited high selectivity for antiamnesic effect over induction of hypothermia compared to YM796.

Endogenous bone-resorbing factors in estrogen deficiency: cooperative effects of IL-1 and IL-6

Estrogen deficiency causes a marked bone loss by stimulating osteoclastic bone resorption. To explore the endogenous bone-resorbing factors involved in estrogen deficiency, we examined the bone-resorbing activity present in the supernatant fraction of mouse bone marrow collected from ovariectomized (OVX) mice. Adding bone marrow supernatants at 20-80% to organ cultures of mouse long bones dose-dependently stimulated bone resorption. The endogenous bone-resorbing activity present in bone marrow supernatants from OVX mice was much higher than that from sham-operated mice 2-4 weeks after surgery, and it was significantly diminished by indomethacin in vitro. Anti-IL-1 alpha antibody completely neutralized the bone-resorbing activity present in bone marrow supernatants from OVX mice. Antibodies against IL-1 beta, IL-6, and IL-6 receptors also neutralized it, but partially. The concentration of IL-1 alpha measured by ELISA was much higher in bone marrow supernatants than in sera, but it was not appreciably changed before or after OVX. The concentration of IL-1 beta in bone marrow supernatants from OVX mice was less than the detection limit. OVX stimulated IL-1 activity in bone marrow supernatants measured by means of the proliferation of thymocytes. However, the level of IL-1 alpha present in bone marrow supernatants from OVX mice was insufficient to stimulate bone resorption. Compared with the serum concentration, bone marrow supernatants contained a much higher level of IL-6 as well, and it was further increased by OVX. However, IL-6 alone present in bone marrow supernatants from OVX mice again did not stimulate bone resorption.(ABSTRACT TRUNCATED AT 250 WORDS)

An IRF-1-dependent pathway of DNA damage-induced apoptosis in mitogen-activated T lymphocytes

Lymphocytes are particularly susceptible to DNA damage-induced apoptosis, a response which may serve as a form of 'altruistic suicide' to counter their intrinsic high potential for mutation and clonal expansion. The tumour suppressor p53 has been shown to regulate this type of apoptosis in thymocytes, but an as yet unknown, p53-independent pathway(s) appears to mediate the same event in mitogen-activated mature T lymphocytes. Here we show DNA damage-induced apoptosis in these T lymphocytes is dependent on the antioncogenic transcription factor interferon regulatory factor (IRF)-1. Thus two different anti-onco-genic transcription factors, p53 and IRF-1, are required for distinct apoptotic pathways in T lymphocytes. We also show that mitogen induction of the interleukin-1 beta converting enzyme (ICE) gene, a mammalian homologue of the Caenorhabditis elegans cell death gene ced-3, is IRF-1-dependent. Ectopic overexpression of IRF-1 results in the activation of the endogenous gene for ICE and enhances the sensitivity of cells to radiation-induced apoptosis.

Decorating actin filaments with troponin T-I complexes and acceleration of their sliding movement on myosin molecules

Actin filaments, when partially decorated with troponin T-I complexes, can slide faster on myosin heads than those with no decoration. Purified troponin T-I complexes bind to actins, and inhibit the actin activated myosin adenosine 5'-triphosphatase activity completely when the molar ratio of troponin T-I complex to actin is increased to 1 to 1. Those actin filaments decorated with troponin T-I complexes up to 20 to 50% of their molar ratio exhibit enhancement of the velocity of sliding on myosins up to 20% compared to those without such decoration. As the molar ratio of decoration further increases, the sliding velocity decreases. These results are consistent with the observation that even if some of actin monomers do not participate in the ATPase activity directly, they can interact with myosin heads and take part in the sliding movement.

The effect of zinc supplementation on pregnancy outcome

OBJECTIVE

To evaluate whether zinc supplementation during pregnancy is associated with an increase in birth weight.

DESIGN

A randomized double-blind placebo-controlled trial.

SETTING

Outpatient clinic and delivery service at the University of Alabama at Birmingham.

PATIENTS

Five hundred eighty medically indigent but otherwise healthy African-American pregnant women with plasma zinc levels below the median at enrollment in prenatal care, randomized at 19 weeks' gestational age. Women were subdivided by the population median body mass index of 26 kg/m2 into two groups for additional analyses.

INTERVENTION

Women who were taking a non-zinc-containing prenatal multivitamin/mineral tablet were randomized to receive either a daily dose of 25 mg of zinc or a placebo until delivery.

MAIN OUTCOME MEASURES

Birth weight, gestational age at birth, and head circumference at birth.

RESULTS

In all women, infants in the zinc supplement group had a significantly greater birth weight (126 g, P = .03) and head circumference (0.4 cm, P = .02) than infants in the placebo group. In women with a body mass index less than 26 kg/m2, zinc supplementation was associated with a 248-g higher infant birth weight (P = .005) and a 0.7-cm larger infant head circumference (P = .007). Plasma zinc concentrations were significantly higher in the zinc supplement group.

CONCLUSIONS

Daily zinc supplementation in women with relatively low plasma zinc concentrations in early pregnancy is associated with greater infant birth weights and head circumferences, with the effect occurring predominantly in women with a body mass index less than 26 kg/m2.