Silencing mediator of retinoic acid and thyroid hormone receptors, as a novel transcriptional corepressor molecule of activating protein-1, nuclear factor-kappaB, and serum response factor

Silencing mediator of retinoic acid and thyroid hormone receptors (SMRT) is known to interact with Sin3 and recruit the histone deacetylases (HDACs) that lead to hypoacetylation of histones and transrepression of target transcription factors. Herein, we found that coexpression of SMRT significantly repressed transactivations by activating protein-1 (AP-1), nuclear factor-kappaB (NFkappaB), and serum response factor (SRF) in a dose-dependent manner, but not in the presence of trichostatin A, a specific inhibitor of HDAC. Similarly, coexpression of HDAC1 and mSin3A also showed repressive effects. Consistent with these results, the C-terminal region of SMRT directly interacted with SRF, the AP-1 components c-Jun and c-Fos, and the NFkappaB components p50 and p65, as demonstrated by the yeast and mammalian two hybrid tests as well as the glutathione S-transferase pull down assays. Thus, we concluded that SMRT serves to recruit Sin3/HDACs to SRF, NFkappaB, and AP-1 in vivo and modulate their transactivation.

Changes in pain threshold and lumbar spinal cord immediate-early gene expression induced by paced and nonpaced mating in female rats

Vaginocervical stimulation (VCS) received during mating is known to induce analgesia and to suppress FOS-immunoreactivity (FOS-IR) in lumbar spinal cord. However, it is not known whether this suppression of FOS-IR reflects inhibition of afferent nociceptive input. The present studies examined whether two immediate-early gene (IEG) products, FOS and Egr-1, covary with nociception by comparing both responses in estrous females that received mating stimulation known to induce varying amounts of FOS-IR in brain. Ovariectomized steroid-treated rats were mated under conditions in which they paced or did not pace sexual contacts with males until receiving 5 or 15 intromissions. Control groups received mounts-without-intromission only from males or remained in their homecages. In experiment I, paced mating resulted in a significant overall suppression of FOS-IR in the lumbar 6 (L6) spinal segment compared to nonpaced and mounts only stimulation. This reduction occurred specifically among paced females receiving five intromissions. In contrast, significant elevations above homecage levels were seen in paced females given 15 intromissions, all nonpaced females, and mounts only animals. The numbers of Egr-1-immunoreactive (Egr-1-IR) cells increased equally above homecage levels in all male-exposed females. In experiment II, females that received five intromissions (paced or nonpaced) showed significant increases in tail-flick latency (TFL) within 5 s (time 0) after mating, while females receiving 15 intromissions showed hyperalgesia (15 nonpaced) or no change (15 paced) in TFL throughout 90 s postmating. Additional females tested immediately after receiving two ejaculations showed analgesia. Paced mating, though more effective than nonpaced mating in suppressing FOS-IR, did not influence the appearance of VCS-induced analgesia. We conclude that the suppression of FOS-IR by paced mating is not related to mating-induced analgesia.

Preactivation permits subsequent stimulation of phospholipase C by G(i)-coupled receptors

In the complex signal transduction networks involving G protein-coupled receptors there are numerous examples where G(i)-linked receptors augment G(q)-dependent signals. The mechanistic basis of such occurrences is thought to entail signal convergence at phospholipase Cbeta (PLCbeta) via the G protein betagamma-dimers. Herein, we explored the possibility that augmentation by betagamma-dimers requires preactivation of PLCbeta. COS-7 cells were transiently cotransfected with cDNAs encoding various combinations of receptors and G protein subunits. The G(i)-coupled delta- and kappa-opioid receptors could not stimulate PLCbeta unless they were coexpressed with Galpha(16). The opioid-induced response was dose-dependent and partially inhibited by pertussis toxin or coexpression with transducin, indicating the involvement of betagamma-subunits released from the G(i) proteins. When PLCbeta was preactivated by constitutively active mutants of Galpha(16), Galpha(q), or Galpha(14), opioids enhanced the activity by 80 to 300% and such responses were mostly pertussis toxin-sensitive. The opioid-induced enhancement was dose-dependent and could not be blocked by staurosporin, a protein kinase C inhibitor. Other G(i)-coupled receptors that were ineffective on their own also acquired the ability to stimulate PLCbeta in the presence of a constitutively active mutant of Galpha(q). Coactivation of endogenous or exogenous G(q)-coupled receptors with the delta-opioid receptor produced strong stimulations of PLCbeta and such responses could be partially blocked by pertussis toxin. These results show that enhancement of G(q)-dependent signals by G(i)-coupled receptors requires activated PLCbeta and is mediated via the betagamma-dimer.

Protective role of nitric oxide-mediated inflammatory response against lipid peroxidation in ultraviolet B-irradiated skin

Ultraviolet (UV) irradiation is known to induce serious oxidative damage in the skin via lipid peroxidation. Nitric oxide (NO) synthesized by keratinocytes, melanocytes and endothelial cells in response to proinflammatory cytokines and UV radiation, has been reported to prevent UV-induced apoptosis in the skin. We have examined the effects of NO on UVB-induced lipid peroxidation in murine skin in vivo. UVB induced a dose-dependent increase in lipid peroxidation of skin extracts in vitro; however, lipid peroxidation in the skin in vivo remained unaffected at irradiation doses of less than 1.0 J cm-2 and decreased significantly at doses over 1.5 J cm-2 (P < 0.01). Time-delayed inhibition of lipid peroxidation in the skin in vivo was observed after irradiation at 1.5 J cm-2. Administration of N G-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO synthesis, enhanced lipid peroxidation (P < 0.05), while it suppressed the ear-swelling response (ESR), a biological marker of inflammation. By contrast, administration of sodium nitroprusside, an NO enhancer, suppressed lipid peroxidation (P < 0. 01), while it enhanced the ESR. Expression of inducible nitric oxide synthase (iNOS) was observed from 12 to 48 h postirradiation at doses of 0.4-1.6 J cm-2. The UVB-induced iNOS expression was markedly inhibited by L-NAME, suggesting that iNOS is a major enzyme in the production of NO. These results suggest that NO acts as a mediator of the inflammatory response in UVB-irradiated skin, and that lipid peroxidation is inversely regulated with the NO-mediated inflammatory response in vivo.

Changes in biochemical bone markers during pregnancy and puerperium

To elucidate the changes in bone turnover during pregnancy and puerperium, we measured serially the levels of serum osteocalcin and urine deoxypyridinoline (Dpy) as markers of bone formation and bone resorption, respectively, in 22 healthy women with normal pregnancy. Nineteen non-pregnant women served as control. The Dpy levels increased significantly at 16 weeks of pregnancy and remained elevated thereafter. The levels of osteocalcin, however, were significantly decreased at 16 weeks of pregnancy and elevated later at 6 weeks postpartum. Bone turnover ratio (Dpy/osteocalcin) continued to rise during pregnancy, but returned to control levels 6 weeks after delivery. Dpy levels and bone turnover ratio during puerperium tended to be higher in 17 breast-feeding women than those of 5 exclusive bottle-feeders. In conclusion, bone resorption begins to increase from the second trimester of pregnancy and calcium release from bone tissue might play a major role in calcium homeostasis during the whole period of pregnancy as well as during lactation.

Relative importance of aldose reductase versus nonenzymatic glycosylation on sugar cataract formation in diabetic rats

The relative importance of sorbitol formation versus nonenzymatic glycosylation and advanced glycosylation end products (AGEs) on sugar cataract formation was examined in diabetic rats. Diabetes was experimentally induced in young, 50 g rats with streptozotocin, and aldose reductase inhibitors were administered in the diet for up to 8 weeks at concentrations of 0.06% for tolrestat or ponalrestat and 0.0125% for AL-1576. Cataract formation was monitored by hand-held slit lamp for up to 11 weeks. Lens polyol levels were monitored by GLC, glycosylated protein levels were spectrophotometrically determined, and AGE products were estimated by fluorescence measurements and ELISA. Sugar cataract formation was observed in all untreated diabetic rats while cataract formation was inhibited in all diabetic rats treated with the AR inhibitors. Lens sorbitol levels were reduced in all ARI-treated rats. Glycosylated lens protein levels were elevated in the diabetic rats, and these levels were not significantly lower in the non-cataractous lenses from ARI-treated diabetic rats. Fluorescence measurements of the lens proteins revealed increased lens AGE levels in all diabetic rats, and these were slightly reduced in the aldose reductase inhibitor treated diabetics. With ELISA, immunoreactive AGEs were only detected in cataractous lenses from the untreated diabetic rats. Immunoreactive AGEs were not detected in the clear lenses of the aldose reductase inhibitor treated diabetics or in the non-diabetic controls. These results support the concept that sugar cataract formation is initiated by the aldose reductase catalyzed intracellular accumulation of polyols and that these sugar cataracts can be prevented through inhibition of aldose reductase.

Acid and base catalyzed intramolecular cyclizations of N-benzoylthiocarbamoyl-acetals

Acid and base catalyzed intramolecular cyclizations of N-benzoylthioureidoacetal, containing four functional groups adjacent to thiourea such as benzocarbamoyl, acetal, thioure and amide, were investigated. The condensation reaction of N-benzoyl thiocarbamoylglycine amide in the presence of 10% aqueous NaOH provided 1-(2,2-dimethoxy)ethyl-imidazolidine-2-thione exclusively. In the presence of pyridine, it was transformed to 2-thiohydantoin. N-Benzoyl thiocarbamoyl glycine amide was completely transformed to an iminothiazolidine exclusively in the presence of Lewis acid such as borontrifluoride etherate or trimethylsilyl iodide. 1-(2,2-Dimethoxy)ethyl-imidazolidine-2-thione was transformed to imidazole[2,1-b]thiazole and pyrazino[5,1-a]imidazole in the presence of BF3.Et2O and formic acid, respectively.

Manganese intoxication

Manganese plays an important role as a cofactor in many enzymatic reactions in humans but in excess amounts can cause irreversible nervous system damage. Although manganism is a rare condition, it can be the cause of complex nervous system symptoms, especially in the setting of environmental exposure. Specifically, manganese is a well-known cause of dystonic parkinsonism. This article highlights several historical descriptions of the clinical manifestations, pathological changes, and attempted therapeutic intervention in manganese intoxication.

A study of dentists' knowledge and beliefs regarding temporomandibular disorders in Korea

The purpose of this study was to examine the knowledge and beliefs regarding TMD (temporomandibular disorders) held by practicing dentists in Seoul, the capital and largest city in Korea. Four aspects of TMD (psychophysiological, psychiatric disorders, chronic pain and pathophysiological) were examined. The results indicate that while the role of psychophysiologic factors in the etiology of TMD and the role of psychiatric disorders is relatively widely acknowledged in the practicing community, there is a high level of controversy regarding the pathophysiology of TMD and the appropriate diagnosis and treatment of these chronic conditions. The findings partially duplicate a similar survey of dentists in Seattle, Washington, and one survey done in Kansas in the United States.

Pseudorabies virus tracing of neural pathways between the uterine cervix and CNS: effects of survival time, estrogen treatment, rhizotomy, and pelvic nerve transection

The transneuronal tracer, pseudorabies virus (PRV), was used to identify pathways from the uterine cervix which may be involved in induction of analgesia and abbreviation of estrus by vaginocervical stimulation. In Experiment I, PRV immunoreactivity (PRV-IR) in brain and spinal cord was examined 3-5 days after injection into the cervix of ovariectomized (OVX) female rats given estrogen (E) or control treatments. No differences in viral labeling were observed between OVX and OVX+E females at any time. PRV-infected cells were observed to increase as a function of time and at progressively higher CNS levels. PRV-IR neurons were first observed on day 3 post-infection at L6 in the SPN. Increased labeling was observed at day 4 in the SPN and the DGC at L6 and S1 spinal segments. Dorsal horn neurons showed PRV-IR by 4.5 days. Five days post-infection, labeling was seen in the IML and lamina X in T12-L1 segments, and in medullary raphe, A5, nPGi, nGi, DMV, lateral reticular, Barrington's nuclei, and in the midbrain PAG. In Experiment II, the effects of bilateral L6 dorsal root rhizotomy (RH) combined with unilateral (UPx) or bilateral (BPx) pelvic nerve transection on PRV infectivity were examined 5 days after infection. Despite reductions in substance P labeling in the dorsal horn following RH, PRV-IR neurons persisted in this area. In RH+UPx females, labeling persisted bilaterally in the SPN and DGC at L6. RH+BPx almost completely eliminated the PRV labeling in L6 and S1. Horizontal sections showed distinct patterns of infectivity within the IML of thoracolumbar and SPN of lumbosacral segments consistent with infection in the hypogastric and pelvic nerves, respectively. Our data indicate that retrograde transport of PRV occurs via the hypogastric and pelvic nerves after injection of the virus into the uterine cervix. Furthermore, significant intraspinal processing is likely to occur between thoracolumbar and lumbosacral levels in the modulation of reproductive tract function.

SPACRCAN, a novel human interphotoreceptor matrix hyaluronan-binding proteoglycan synthesized by photoreceptors and pinealocytes

The interphotoreceptor matrix is a unique extracellular complex occupying the interface between photoreceptors and the retinal pigment epithelium in the fundus of the eye. Because of the putative supportive role in photoreceptor maintenance, it is likely that constituent molecules play key roles in photoreceptor function and may be targets for inherited retinal disease. In this study we identify and characterize SPACRCAN, a novel chondroitin proteoglycan in this matrix. SPACRCAN was cloned from a human retinal cDNA library and the gene localized to chromosome 3q11.2. Analysis of SPACRCAN mRNA and protein revealed that SPACRCAN is expressed exclusively by photoreceptors and pinealocytes. SPACRCAN synthesized by photoreceptors is localized to the interphotoreceptor matrix where it surrounds both rods and cones. The functional protein contains 1160 amino acids with a large central mucin domain, three consensus sites for glycosaminoglycan attachment, two epidermal growth factor-like repeats, a putative hyaluronan-binding motif, and a potential transmembrane domain near the C-terminal. Lectin and Western blotting indicate an M(r) around 400,000 before and 230,000 after chondroitinase ABC digestion. Removal of N- and O-linked oligosaccharides reduces the M(r) to approximately 160,000, suggesting that approximately 60% of the mass of SPACRCAN is carbohydrate. Finally, we demonstrate that SPACRCAN binds hyaluronan and propose that associations between SPACRCAN and hyaluronan may be involved in organization of the insoluble interphotoreceptor matrix, particularly as SPACRCAN is the major proteoglycan present in this matrix.

A subclass of Ras proteins that regulate the degradation of IkappaB

Small guanosine triphosphatases, typified by the mammalian Ras proteins, play major roles in the regulation of numerous cellular pathways. A subclass of evolutionarily conserved Ras-like proteins was identified, members of which differ from other Ras proteins in containing amino acids at positions 12 and 61 that are similar to those present in the oncogenic forms of Ras. These proteins, kappaB-Ras1 and kappaB-Ras2, interact with the PEST domains of IkappaBalpha and IkappaBbeta [inhibitors of the transcription factor nuclear factor kappa B (NF-kappaB)] and decrease their rate of degradation. In cells, kappaB-Ras proteins are associated only with NF-kappaB:IkappaBbeta complexes and therefore may provide an explanation for the slower rate of degradation of IkappaBbeta compared with IkappaBalpha.

Analysis of urinary S-phenylmercapturic acid and trans, trans-muconic acid as exposure biomarkers of benzene in petrochemical and industrial areas of Korea

OBJECTIVES

Recently, S-phenylmercapturic acid (S-PMA) and trans,trans-muconic acid (t,t-MA) in urine have been proposed as reliable biomarkers for monitoring occupational exposure to benzene. The aim of this study was to test the applicability of S-PMA and t,t-MA as exposure biomarkers and to monitor the occupational exposure level and the extent of environmental contamination from benzene in Korea.

METHODS

The urinary excretion of S-PMA and t,t-MA in rats after the intraperitoneal administration of benzene (0.88-800 mg/kg body weight, 7 days) was examined. These biomarkers were also validated in human urine samples collected from elementary schoolchildren in several industrial areas including chemical manufacturing plants, oil refineries, and natural gas-producing installations in Korea. Urine was collected from elementary schoolchildren in a mountain village with no known occupational exposure to benzene and air pollution as the reference group.

RESULTS

In rats, there was a significant relationship between the benzene concentration and the excretion of the urinary S-PMA and t,t-MA as a function of concentration, and the excretion of benzene metabolites peaked on the first day after intraperitoneal administration. In human urine, higher levels of S-PMA and t,t-MA were detected more frequently in petrochemical industrial areas than in areas with no known occupational exposure to benzene.

CONCLUSIONS

These results show that the quantitative determination of S-PMA and t,t-MA in urine can be used as a reliable exposure biomarker for benzene, and they also suggest that extensive attention to benzene exposure is needed for maintaining the health of the population in Korea.

B-cell lymphoma of bronchus-associated lymphoid tissue (BALT): CT features in 10 patients

PURPOSE

The purpose of this work was to describe the CT findings of pathologically confirmed bronchus-associated lymphoid tissue (BALT) lymphoma in 10 patients.

METHOD

The CT examinations of 10 patients with pathologically proven BALT lymphoma were reviewed retrospectively by two radiologists. Evaluated findings included number and distribution of lesions. We also assessed other CT findings such as presence of airspace consolidation, nodules, ground-glass attenuation, bubble-like radiolucencies, air bronchogram, bronchial dilatation, and lymphadenopathy.

RESULTS

Pulmonary lesions were revealed as airspace consolidation in six patients (60%) and nodule(s) in six (60%). Multiplicity of disease was seen in seven patients (70%) and bilateral lung lesions in six (60%). Areas of ground-glass attenuation were seen in seven patients (70%). Bubble-like radiolucencies were present in five patients (50%) and air bronchogram in nine (90%). Findings of bronchial dilatation and lymphadenopathy were seen in three patients (30%).

CONCLUSION

BALT lymphomas usually appear as airspace consolidation or nodules with air bronchogram or adjacent ground-glass attenuation at CT. These findings are similar to previous descriptions of pseudolymphomas. Multiple bilateral lesions are common in BALT lymphoma. Bubble-like radiolucencies have not been described previously and can be an additional finding of BALT lymphoma.

Validation of immunoassays for bioanalysis: a pharmaceutical industry perspective

Immunoassays are bioanalytical methods in which quantitation of the analyte depends on the reaction of an antigen (analyte) and an antibody. Although applicable to the analysis of both low molecular weight xenobiotic and macromolecular drugs, these procedures currently find most consistent application in the pharmaceutical industry to the quantitation of protein molecules. Immunoassays are also frequently applied in such important areas as the quantitation of biomarker molecules which indicate disease progression or regression, and antibodies elicited in response to treatment with macromolecular therapeutic drug candidates. Currently available guidance documents dealing with the validation of bioanalytical methods address immunoassays in only a limited way. This review highlights some of the differences between immunoassays and chromatographic assays, and presents some recommendations for specific aspects of immunoassay validation. Immunoassay calibration curves are inherently nonlinear, and require nonlinear curve fitting algorithms for best description of experimental data. Demonstration of specificity of the immunoassay for the analyte of interest is critical because most immunoassays are not preceded by extraction of the analyte from the matrix of interest. Since the core of the assay is an antigen-antibody reaction, immunoassays may be less precise than chromatographic assays; thus, criteria for accuracy (mean bias) and precision, both in pre-study validation experiments and in the analysis of in-study quality control samples, should be more lenient than for chromatographic assays. Application of the SFSTP (Societe Francaise Sciences et Techniques Pharmaceutiques) confidence interval approach for evaluating the total error (including both accuracy and precision) of results from validation samples is recommended in considering the acceptance/rejection of an immunoassay procedure resulting from validation experiments. These recommendations for immunoassay validation are presented in the hope that their consideration may result in the production of consistently higher quality data from the application of these methods.

CT and US findings of multilocular cystic renal cell carcinoma

OBJECTIVE

Multilocular cystic renal cell carcinoma (MCRCC) is a recently described variety of renal cell carcinoma with characteristic pathologic and clinical features. The purpose of this study was to analyze the imaging findings of MCRCCs.

MATERIALS AND METHODS

Ten adult patients with pathologically proven unilateral MCRCC who underwent renal US and CT were included in this study. The radiologic findings were retrospectively evaluated for cystic content, wall, septum, nodularity, calcification and solid portion by three radiologists who established a consensus. Imaging and postnephrectomy pathologic findings were compared.

RESULTS

All patients were adults (six males and four females) and their ages ranged from 33 to 68 years (mean, 46). On US and CT images, all tumors appeared as well-defined multilocular cystic masses composed of serous or complicated fluid. In all patients, unenhanced CT scans revealed hypodense cystic portions, and in four tumors, due to the presence of hemorrhage or gelatinous fluid, some hyperdense areas were also noted. In no tumor was an expansile solid nodule seen in the thin septa, and in only one was there dystrophic calcification in a septum. Small areas of solid portion constituting less than 10% of the entire lesion were found in six of the ten tumors, and these areas were slightly enhanced on enhanced CT scans. In all patients, imaging and pathologic findings correlated closely.

CONCLUSION

On US and CT images, MCRCC appeared as a well-defined multilocular cystic mass with serous, proteinaceous or hemorrhagic fluid, with no expansile solid nodules in the thin septa, and sometimes with small slightly enhanced solid areas. Where radiologic examinations demonstrate a cystic renal mass of this kind in adult males, MCRCC should be included in the differential diagnosis.

Simultaneous assay of morphine, morphine-3-glucuronide and morphine-6-glucuronide in human plasma using normal-phase liquid chromatography-tandem mass spectrometry with a silica column and an aqueous organic mobile phase

Morphine (MOR) is an opioid analgesic used for the treatment of moderate to severe pain. MOR is extensively metabolized to morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G). A rapid and sensitive method that was able to reliably detect at least 0.5 ng/ml of MOR and 1.0 ng/ml of M6G was required to define their pharmacokinetic profiles. An LC-MS-MS method was developed in our laboratory to quantify all three analytes with the required sensitivity and a rapid turnaround time. A solid-phase extraction (SPE) was used to isolate MOR, M3G, M6G, and their corresponding deuterated internal standards from heparinized plasma. The extract was injected on a LC tandem mass spectrometer with a turbo ion-spray interface. Baseline chromatographic separation among MOR, M3G, and M6G peaks was achieved on a silica column with an aqueous organic mobile phase consisting of formic acid, water, and acetonitrile. The total chromatographic run time was 3 min per injection, with retention times of 1.5, 1.9 and 2.4 min for MOR, M6G, and M3G, respectively. Chromatographic separation of M3G and M6G from MOR was paramount in establishing the LC-MS-MS method selectivity because of fragmentation of M3G and M6G to MOR at the LC-MS interface. The standard curve range in plasma was 0.5-50 ng/ml for MOR, 1.0-100 ng/ml for M6G, and 10-1000 ng/ml for M3G. The inter-day precision and accuracy of the quality control (QC) samples were <7% relative standard deviation (RSD) and <6% relative error (R.E.) for MOR, <9% RSD and <5% R.E. for M6G, and <3% RSD and <6% R.E. for M3G. Analyte stability during sample processing and storage were established. Method ruggedness was demonstrated by the reproducible performance from multiple analysts using several LC-MS-MS systems to analyze over one thousand samples from clinical trials.

Unusual gastric tumors: radiologic-pathologic correlation

The overlap of radiologic findings in many gastric tumors makes differentiation difficult. However, some unusual gastric tumors have characteristic radiologic features that may suggest a specific diagnosis. At barium study, lipomas typically manifest as a smooth submucosal mass or an ulcerated lesion with a "bull's-eye" appearance that is indistinguishable from other mesenchymal tumors. At computed tomography (CT), lipomas usually manifest as well-circumscribed submucosal masses with fat attenuation. At radiology, glomus tumors appear as smooth submucosal masses with or without ulceration and may contain tiny flecks of calcification. These tumors frequently demonstrate strong enhancement on early-phase contrast material-enhanced images. At barium study, lymphangiomas may appear as smooth intramural masses that are indistinguishable from other mesenchymal tumors. At CT, they manifest as non-enhancing extramucosal masses with homogeneous low attenuation. Diffuse lesions in Brunner gland hamartoma manifest as multiple small nodules, producing a characteristic "cobblestone" appearance. Lymphomas may have typical imaging features (eg, more pronounced and homogeneous mural thickening) that can help differentiate them from adenocarcinoma. In addition, adenocarcinomas may demonstrate unusual findings such as transpyloric spread, unusually large polyps, or intratumoral calcifications. Familiarity with these radiologic features of gastric tumors can help ensure correct diagnosis and proper management.

Biosynthesis of novel exopolymers by Aureobasidium pullulans

Aureobasidium pullulans ATCC 42023 was cultured under aerobic conditions with glucose, mannose, and glucose analogs as energy sources. The exopolymer extracts produced under these conditions were composed of glucose and mannose. The molar ratio of glucose to mannose in the exopolymer extract and the molecular weight of the exopolymer varied depending on the energy source and culture time. The glucose content of exopolymer extracts formed with glucose and mannose as the carbon sources was between 91 and 87%. The molecular weight decreased from 3.5 x 10(6) to 2.12 x 10(6) to 0.85 x 10(6) to 0.77 x 10(6) with culture time. As the culture time increased, the glucose content of the exopolymer extract formed with glucosamine decreased from 55 +/- 3 to 29 +/- 2 mol%, and the molecular weight increased from 2.73 x 10(6) to 4.86 x 10(6). There was no evidence that glucosamine was directly incorporated into exopolymers. The molar ratios of glucose to mannose in exopolymer extracts ranged from 87 +/- 3:13 +/- 3 to 28 +/- 2:72 +/- 2 and were affected by the energy source added. On the basis of the results of an enzyme hydrolysis analysis of the exopolymer extracts and the compositional changes observed, mannose (a repeating unit) was substituted for glucose, which gave rise to a new family of exopolymer analogs.

A nuclear factor, ASC-2, as a cancer-amplified transcriptional coactivator essential for ligand-dependent transactivation by nuclear receptors in vivo

Many transcription coactivators interact with nuclear receptors in a ligand- and C-terminal transactivation function (AF2)-dependent manner. We isolated a nuclear factor (designated ASC-2) with such properties by using the ligand-binding domain of retinoid X receptor as a bait in a yeast two-hybrid screening. ASC-2 also interacted with other nuclear receptors, including retinoic acid receptor, thyroid hormone receptor, estrogen receptor alpha, and glucocorticoid receptor, basal factors TFIIA and TBP, and transcription integrators CBP/p300 and SRC-1. In transient cotransfections, ASC-2, either alone or in conjunction with CBP/p300 and SRC-1, stimulated ligand-dependent transactivation by wild type nuclear receptors but not mutant receptors lacking the AF2 domain. Consistent with an idea that ASC-2 is essential for the nuclear receptor function in vivo, microinjection of anti-ASC-2 antibody abrogated the ligand-dependent transactivation of retinoic acid receptor, and this repression was fully relieved by coinjection of ASC-2-expression vector. Surprisingly, ASC-2 was identical to a gene previously identified during a search for genes amplified and overexpressed in breast and other human cancers. From these results, we concluded that ASC-2 is a bona fide transcription coactivator molecule of nuclear receptors, and its altered expression may contribute to the development of cancers.

Indomethacin treatment decreases renal blood flow velocity in human neonates

This study was designed to evaluate the effect of indomethacin (ID) on renal perfusion in 13 neonates with symptomatic patent ductus arteriosus (PDA). Serial blood flow velocity in the left renal artery was measured just before and at 10, 30, 45, 60, 75 and 90 min after ID administration. Serum creatinine (Cr), sodium (Na), and osmolarity were measured just before, at 12 and 24 h, and at 3 days after ID administration. Timed urine also was collected for measurement of amount, fractional excretion of Na (FE(Na)), and creatinine clearance (C(Cr)). ID decreased end-diastolic flow velocity of renal artery and increased Pourcelot's index, starting at 10 min and lasting for 75 min (p < 0.05). Serum Cr significantly increased at 12 h, and hourly urine output and C(Cr) decreased for 24 h. Serum Na and osmolarity decreased for a period of at least 3 days (p < 0.05). FE(Na) decreased at 12-24 h (p < 0.05). We conclude that ID treatment can induce significant renal dysfunction due to diminution of renal perfusion in human neonates.

Steroid receptor coactivator-1 and its family members differentially regulate transactivation by the tumor suppressor protein p53

The tumor suppressor protein p53 exerts its cell cycle-regulatory effects through its ability to function as a sequence-specific DNA-binding transcription factor. Herein, we show that p53 physically interacts with specific subregions of steroid receptor coactivator-1 (SRC-1) and its family members, p/CIP (p300/CBP interacting protein), xSRC-3, and AIB1 (amplified in breast cancer), originally isolated as transcription coactivators of nuclear receptors, as demonstrated by the yeast and mammalian two-hybrid tests as well as glutathione S-transferase pull-down assays. Interestingly, cotransfection of HeLa cells with SRC-1- or p/CIP expression vector potentiated the p53-mediated transactivation, whereas AIB1 and xSRC-3 were repressive. All of these SRC-1 members, however, similarly stimulated transactivation mediated by nuclear receptors and AP-1, as previously described. These results suggest that SRC-1 and its family members may differentially modulate the p53 transactivation in vivo.

Unusual gastric tumors: radiologic-pathologic correlation

The overlap of radiologic findings in many gastric tumors makes differentiation difficult. However, some unusual gastric tumors have characteristic radiologic features that may suggest a specific diagnosis. At barium study, lipomas typically manifest as a smooth submucosal mass or an ulcerated lesion with a "bull's-eye" appearance that is indistinguishable from other mesenchymal tumors. At computed tomography (CT), lipomas usually manifest as well-circumscribed submucosal masses with fat attenuation. At radiology, glomus tumors appear as smooth submucosal masses with or without ulceration and may contain tiny flecks of calcification. These tumors frequently demonstrate strong enhancement on early-phase contrast material-enhanced images. At barium study, lymphangiomas may appear as smooth intramural masses that are indistinguishable from other mesenchymal tumors. At CT, they manifest as non-enhancing extramucosal masses with homogeneous low attenuation. Diffuse lesions in Brunner gland hamartoma manifest as multiple small nodules, producing a characteristic "cobblestone" appearance. Lymphomas may have typical imaging features (eg, more pronounced and homogeneous mural thickening) that can help differentiate them from adenocarcinoma. In addition, adenocarcinomas may demonstrate unusual findings such as transpyloric spread, unusually large polyps, or intratumoral calcifications. Familiarity with these radiologic features of gastric tumors can help ensure correct diagnosis and proper management.

Optimum ratio of distraction in double level tibial lengthening

The authors reviewed 43 double level tibial lengthenings by Ilizarov technique in 34 consecutive patients (6-31 years old), and investigated the factors affecting regenerate bone healing to determine the optimum ratio of distraction rate or magnitude of lengthening at the proximal and distal osteotomy sites. Length gain averaged 6.1 cm (range, 2.5-12.3 cm), equivalent to a 28% increase of the segment. The variables investigated included age, gender, concomitant deformity correction, etiology, and the amount of length gain. The healing index averaged 1.8 months per centimeter proximally and 2.8 months per centimeter distally. Age and the amount of length gain affected the healing index at proximal and distal lengthening sites. However, the proximal to distal healing index ratio, which averaged 0.72, was not affected by any parameters investigated. This study suggests that to minimize external fixation treatment time, the distraction rate, or amount of length gain, of the distal osteotomy site should be approximately 3/4 that of the proximal site in the double level tibial lengthening.

Cloning and characterization of the chloroplast elongation factor EF-Tu cDNA of Oryza sativa L

From the rice leaf cDNA library, we have cloned a cDNA encoding rice chloroplast translational elongation factor EF-Tu (tufA). The rice tufA cDNA clone contains 1678 nucleotides and codes for a 467 amino acid protein including a putative chloroplast transit peptide of 59 amino acid residues. The predicted molecular mass of the mature protein is approximately 45 kDa. This cDNA clone contains the 61 nucleotides of the 5' untranslated region (UTR) and the 213 nucleotides of 3' UTR. Amino acid sequence identity of the rice tufA with the mature chloroplast EF-Tu proteins of tobacco, pea, arabidopsis, and soybean ranges from 83% to 86%. The deduced polypeptide of the rice tufA cDNA contains GTP binding domains in its N-terminal region and chloroplast EF-Tu signature regions in the C-terminal region. The rice tufA appears to exist as a single copy gene, although its homologues of maize and oat exist as multiple copy genes. The rice tufA gene is located in chromosome 1 and is more highly expressed in the leaf than in root tissue.