Hyaluronic acid is increased in the skin and urine in patients with amyotrophic lateral sclerosis

We performed morphological studies of skin and measured glycosaminoglycans in the urine from patients with sporadic amyotrophic lateral sclerosis (ALS) and control subjects. The wide spaces separating collagen bundles reacted strongly with alcian blue stain in ALS patients and stained more markedly as ALS progressed. Staining with alcian blue was virtually eliminated by Streptomyces hyaluronidase. The urinary excretion of hyaluronic acid (HA) (mg/day) was significantly increased (P < 0.01) in ALS patients compared with that of control subjects, and there was a significant positive correlation between the excreted amount of HA and the duration of illness in advanced ALS patients with a duration of more than 2 years from clinical onset (r = 0.72, P < 0.02). We suggest that sporadic ALS includes a metabolic disorder of HA in which an accumulation of HA in the skin is linked to an increased urinary excretion of HA.

[Long-term survival after treatment of thoracic aneurysms by thromboexclusion operation]

Since 1982, fourteen patients with aortic aneurysms received thromboexclusion operation. This method was performed in 7 patients with dissecting aortic aneurysms, 6 patients with true thoracic aneurysms, and 1 patient with true thoracoabdominal aneurysm. Among them, 12 patients received the operation of ascending aorta-supraceliac abdominal aorta bypass, one patient received descending aorta-descending aorta bypass, and another one received bilateral axillo-iliac artery bypass. Graft sizes in diameter were from 16 mm to 22 mm. 9 patients received permanent paired-clamps at both the proximal and the distal parts of the thoracic aneurysm, and 5 patients received permanent single-clamp only at the proximal part of the thoracic aneurysm. 5 patients (35.7%) died perioperatively because of low output syndrome, cerebral infarction, hepato-renal insufficiency, and aneurysmal rupture, respectively. 4 late deaths (28.6%) occurred after 4 months, 5 months, 26 months, and 5 years of operation, respectively. Among them, three deaths were due to aneurysmal rupture and one due to heart failure. Although paired-clamps at both the proximal and the distal parts of the thoracic aneurysm were performed in 1 to 3 ruptured-cases, thrombo-occlusion of the thoracic aorta did not occur in any of the cases. Long-term survival was 35.7% in 5 patients after 14 years and 4 months of mean follow-up. Although a single-clamp only at the proximal part of the thoracic aneurysm was performed in 2 of these 5 cases, thrombo-occlusion of the thoracic aorta occurred in all cases. For the four survivors of them, we ran a follow-up survey and found left ventricular hypertrophic pattern in ECG, concentric left ventricular hypertrophy in UCG, and hypertension, but those were absent before operation. We conclude that thromboexclusion method for thoracic aneurysm should be limited only to high-risk patients particularly in bad conditions or to cases with severe adhesion to lung which seem to be inaccessible through direct approach.

Local production of corticotropin releasing hormone is increased in experimental intestinal inflammation in rats

BACKGROUND/AIMS

Corticotropin releasing hormone (CRH) suppresses immunological functions via stimulation of the pituitary-adrenal axis, but is also found in peripheral tissues. Peripheral proinflammatory activity of CRH is suggested by increased tissue concentrations in arthritis and in vitro immunostimulatory effects. This study evaluated intestinal CRH concentrations, immunolocalisation, and synthesis in chronic enterocolitis and investigated in vitro responsiveness of lamina propria mononuclear cells to CRH.

METHODS

Chronic granulomatous enterocolitis was induced by intramural injection of peptidoglycan-polysaccharide polymers in the ileocaecal region of Lewis rats. CRH protein was measured in caecal specimens by immunohistochemistry and radioimmunoassay and caecal CRH mRNA expression was analysed by reverse transcriptase polymerase chain reaction.

RESULTS

In the chronically inflamed caecum abundant immunoreactive CRH was found in inflammatory cells, mesenchymal cells, as well as in myenteric plexi. In contrast, only a few CRH containing cells were detected in normal and HSA injected control caecums. Moreover, caecal CRH protein levels were increased during chronic enterocolitis. Local CRH synthesis as indicated by mRNA expression was considerably increased in chronic enterocolitis whereas it was undetectable or low in uninflamed caecum. In addition, CRH stimulated in vitro proliferation of lamina propria mononuclear cells and inhibited mitogen induced proliferation.

CONCLUSION

Increased CRH protein and mRNA expression in chronic enterocolitis and responsiveness of intestinal mononuclear cells to CRH indicate an immunomodulatory role for locally produced CRH in intestinal inflammation.

[Potentiation of procaine-induced local sensory block by verapamil in rats]

We have studied the effects of calcium-channel blocker, verapamil, on procaine-induced local sensory block. Standardized tail-flick (TF) test was used to investigate the duration and intensity of procaine-induced local conduction block in rats. After obtaining baseline TF latencies (mean; 3.3 sec), two 100 microliters of 0.4% procaine alone, a combination of 0.4% procaine and verapamil (100 micrograms, or 200 micrograms), or a large dose of verapamil (200 micrograms) were injected to the opposite sites of the tail base and TF test was performed every five minutes for 45 minutes. A large dose of verapamil showed no prolongation of TF latencies. The administration of 0.4% procaine alone produced a significant increase of TF latencies and the peak effect of % MPE (percent maximum possible effect) was demonstrated at 4 minutes after the drug injection (mean % MPE; 37.0%). Coadministration of 0.4% procaine and two doses of verapamil produced significant increases of % MPE in a dose-dependent fashion. It was concluded that sensory block by procaine of the peripheral nerves is potentiated by coadministration of calcium-channel blocker, verapamil.

Identification of a vitamin D3-response element that overlaps a unique inverted TATA box in the rat bone sialoprotein gene

Bone sialoprotein (BSP), an early marker of osteoblast differentiation, has been implicated in the nucleation of hydroxyapatite during bone formation de novo. Our studies, using the osteoblastic cell line ROS 17/2.8, have revealed that rat BSP gene expression is suppressed by 1,25-dihydroxyvitamin D3[1,25(OH)2D3], which is a powerful regulator of bone formation and resorption. To determine the molecular basis of the transcriptional suppression of BSP gene transcription by 1,25(OH)2D3, we have conducted transient transfection analyses with chimaeric constructs of the rat BSP gene promoter linked to a luciferase reporter gene. 1,25(OH)2D3 suppressed expression in all constructs, including a short construct (pLUC 3; nt -116 to +60) that contained a putative vitamin D3-response element (VDRE; AGGGTTTATAGGTCA; nt -28 to -14) that overlaps a unique inverted TATA (TTTATA) box. Mobility shift assays demonstrated strong binding of recombinant human vitamin D3 receptor protein (hVDR) to the VDRE. Point mutations introduced into each half-site and analysed for 1,25(OH)2D3-mediated suppression of transcription and for hVDR binding either decreased or increased both transcriptional suppression and binding. In comparison with activating VDREs, the rat BSP VDRE bound VDR-VDR homodimers more avidly than VDR-RXR alpha heterodimers (where RXR is retinoid X receptor). These studies have therefore identified a novel 1,25(OH)2D3 suppressor element that overlaps the inverted TATA box in the rat BSP gene and indicate that transcriptional suppression of the rat BSP gene by 1,25(OH)2D3 might involve competition between the VDR and the TATA binding protein (TBP).

[Constrictive pericarditis with dissecting aortic aneurysm (DeBakey type II)]

We experienced a case of constrictive pericarditis with dissecting aortic aneurysm (DeBakey type II). The patient complained of orthopnea and leg edema. The cause of constrictive pericarditis was pericardial effusion due to dissecting aortic aneurysm. Ascending aortic replacement with graft and decortication of thickened pericardium were performed. We confirmed the decrease of CVP and PAP intraoperatively. Postoperative course was uneventful.

Human UDP-galactose translocator: molecular cloning of a complementary DNA that complements the genetic defect of a mutant cell line deficient in UDP-galactose translocator

We have cloned a cDNA that codes for a putative human UDP-galactose translocator (UGT) protein. The cDNA contained an open reading frame of 1,179 base pairs encoding a novel protein of 393 amino acids. Introduction of the open reading frame sequence into a UGT-deficient mouse cell line, Had-1, complemented the genetic defect of the mutant, namely the inability to transport UDP-galactose from the cytosol to the Golgi lumen, as judged from the lectin-sensitivity spectrum of the transformant. To our knowledge, this is the first mammalian nucleotide-sugar translocator whose cDNA sequence has been described.

Influence of continuous positive airway pressure on EMG activities of the cricothyroid and posterior cricoarytenoid muscles of the canine larynx

OBJECTIVES

We investigated the effect of different levels of continuous positive airway pressure (CPAP) on the cricothyroid (CT; a tensor muscle of the vocal folds) and posterior cricoarytenoid (PCA; sole abductor muscle of the vocal folds) muscles in dogs.

DESIGN

Prospective, controlled animal study.

SUBJECTS

Nine mongrel dogs of both sexes.

SETTING

University research laboratory.

INTERVENTIONS

After insertion of a cuffed tracheotomy tube low in the neck the compound EMG responses of the CT and PCA muscles during spontaneous respiration were measured simultaneously under different levels (2, 4, 6, and 8 cmH2O) of positive end-expiratory pressure (PEEP).

MEASUREMENTS AND RESULTS

The CT showed a progressive increase in phasic expiratory EMG activity with the application of graded levels of PEEP. Application of PEEP over 4 cmH2O produced significant increases in the phasic CT activity (P < 0.05). In contrast to the CT, the PCA failed to increase phasic inspiratory EMG activity statistically until a 8 cmH2O of PEEP was applied (P < 0.05). The phasic expiratory CT and inspiratory PCA activities were 297.9 +/- 77.6 and 124.5 +/- 22.9, respectively, at the application of 6 cmH2O of PEEP (percentage of control, mean +/- SD).

CONCLUSION

This study confirms the difference in sensitivity between adductor and abductor laryngeal muscles, demonstrating that the intrinsic laryngeal muscles do not all behave similarly after the application of CPAP.

Potentiation of local lignocaine-induced sensory block by calcium channel blockers in rats

We have studied the effects of three different types of calcium channel blockers (verapamil, diltiazem, and nicardipine) on local lignocaine sensory block. The standardized tail flick test was used to measure the duration and degree of lignocaine-induced conduction block in rats. After obtaining baseline tail flick latencies (mean 3.2 s), two 100-microliter doses of 0.3% lignocaine alone, a combination of verapamil 25, 100 or 200 micrograms, diltiazem 25, 100 or 200 micrograms, or nicardipine 0.5, 1.0 or 2.0 micrograms, and a large dose of calcium channel blockers (verapamil 200 micrograms, diltiazem 200 micrograms or nicardipine 2.0 micrograms) were injected on opposite sites of the tail base and the tail flick test was performed every 5 min for 45 min. A large dose of the calcium channel blockers showed no prolongation of tail flick latencies. Administration of 0.3% lignocaine alone produced a significant increase in tail flick thresholds and the peak effect of the percentage maximum possible effect (% MPE) was demonstrated at 5 min after drug injection (mean % MPE 28.8%; P < 0.01 vs baseline). Co-administration of 0.3% lignocaine and three doses of verapamil produced significant increases in area under the curve (AUC) in a dose-dependent fashion. Mean AUC values for 0.3% lignocaine alone and a combination of verapamil 25, 100 or 200 micrograms were 217.5, 502.5, 529.1 and 1600.3, respectively. Almost similar patterns of augmentation in AUC values were demonstrated after addition of different doses of diltiazem or nicardipine to 0.3% lignocaine. We conclude that the use of mixtures of local anaesthetic and calcium channel blocker potentiated lignocaine sensory block at the level of the peripheral nerves.

Decreased cytochrome c oxidase activity but unchanged superoxide dismutase and glutathione peroxidase activities in the spinal cords of patients with amyotrophic lateral sclerosis

The cause of selective degeneration of motor neurons in the ventral horn of the spinal cord associated with amyotrophic lateral sclerosis (ALS) has still not been elucidated. Recently, so-called oxidative stress has been suggested to be a significant factor in the pathogenesis of this disease. We measured the antioxidant actions of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and cytochrome c oxidase (CO) of the human spinal cord in patients with ALS in comparison with those in control patients. Total SOD activity in spinal cord transections from patients with sporadic ALS was not significantly different from the controls in ventral, lateral, or dorsal regions, although enzymic activity was relatively higher in the ventral compared with the dorsal region. GSH-Px activity in the spinal cord of ALS patients was not very different from that in the control tissue. In contrast, CO activity was significantly reduced in all three regions of the spinal cord in patients with ALS, although the reduction was more marked in the ventral region. These results suggest that reactive oxygen species may attack the mitochondrial respiratory chain, leading eventually to the degeneration of vulnerable motor neurons in the spinal cord, even though no obvious changes in the activity of antioxidant enzymes are detectable.

AP-1 regulation of the rat bone sialoprotein gene transcription is mediated through a TPA response element within a glucocorticoid response unit in the gene promoter

Bone sialoprotein (BSP), a protein which has been implicated in the initial mineralization of newly-formed bone, provides an early phenotypic marker for differentiated osteoblasts. BSP expression is induced by glucocorticoids in association with osteoblast differentiation, and a glucocorticoid response element (GRE) overlapping a putative TRE (TPA, 12-O-tetradecanoyl-phorbol 13-acetate, response element) site has been identified in the rat BSP promoter (Ogata et al., 1995). Since AP-1 and the glucocorticoid receptor have a central role in regulating cell proliferation and differentiation, we have studied AP-1 activity, stimulated by 100 ng/ml TPA in normal fetal rat calvarial cells and in transformed rat osteosarcoma cells (ROS 17/2.8). A transient induction of both c-fos and c-jun mRNAs by TPA was observed in both cell populations, together with an associated suppression of BSP mRNA in the fetal rat calvarial cells. Rat BSP promoter constructs, transiently transfected into ROS 17/2.8 cells, were used to show that TPA suppressed transcription of a luciferase construct (-938/+60; pLUC6) that included the GRE/TRE, but not transcription of shorter contructs lacking this element. Notably, suppression of pLUC6 transcription by TPA was abrogated in the presence of the synthetic glucocorticoid, dexamethasone. Gel mobility shift analyses were performed using two double-stranded synthetic oligonucleotides. These encompassed the TRE and either the distal pair of GRE half-sites (-936/ -910; GRE3) or the proximal pair of GRE half-sites (-925/-899; GRE 4) that comprise the GRE/AP-1 element. The assay showed binding of both AP-1 complexes and recombinant c-Jun homodimers. Additionally, either the c-Jun or glucocorticoid receptor could displace its counterpart from the GRE/TRE but not from consensus GRE and TRE oligonucleotides, indicating that the abrogation of AP-1-mediated gene suppression by glucocorticoids could involve competitive binding. These studies, therefore, have identified a glucocorticoid response unit through which c-Fos and c-Jun can suppress the expression of BSP in proliferating pre-osteoblastic cells and through which glucocorticoids can ameliorate the effects of AP-1 and promote osteoblast differentiation and the associated expression of BSP.

Inhibition of platelet aggregation by endocardial endothelial cells

We assessed the anti-platelet properties of endocardial endothelial cells (EECs) by measuring platelet aggregation after brief interaction with EECs isolated from the right ventricles of porcine hearts. Platelet aggregation in response to thrombin was significantly inhibited by brief incubation of platelet suspensions over EEC monolayers. Pretreatment of EECs with indomethacin restored platelet reaction but that with L-NAME and hemoglobin (Hb) did not. The PGI2 content of platelet suspensions after interaction with cultured EECs was significantly correlated with the inhibition of platelet aggregation. These results suggest that EECs inhibit platelet aggregation by releasing PGI2.

[Use of Warm Touch for intraoperative hypothermia]

A 63-year old man was scheduled for nephrectomy and cholecystectomy. Anesthesia was maintained by oxygen-nitrous oxide-isoflurane (0.5 approximately 1%) and epidural anesthesia. Operation was performed with the patient on left decubitus position. At this time, rectal temperature as his core temperature was 35.8 degrees C. Active warming with electrical warming mattress was started and the room temperature was maintained at 25 degrees C during the operation. Thirty minutes after the abdominal incision, rectal temperature decreased to 34.5 degrees C. Active warming was started with forced-air warming system (Warm Touch, Mallinckrodt Medical Co.) on his upper body. Ten minutes after warming, his body temperatures were restored gradually. Three hours after using Warm Touch, rectal temperature recovered to 36.1 degrees C. The intraoperative course was uneventful. At the end of the operation, the patient showed no shivering and general condition was good. In this case, Warm Touch is useful to restore body temperature against intraoperative hypothermia during abdominal surgery.

Cardioprotective effect of nicorandil in histidine-tryptophan-ketoglurate solution during the cold storage of isolated hearts

We compared the efficacy of using histidine-tryptophan-ketoglurate (HTK) solution with that of University of Wisconsin (UW) solution for heart preservation in an isolated rat heart preparation. Nicorandil (NCR) exerts its action as an ATP-sensitive potassium channel opener at low extracellular potassium concentrations, and HTK solution has a low potassium concentration. Therefore, we also investigated the efficacy of using HTK solution with NCR following 12-hr preservation. Hearts isolated from male Wistar rats were mounted on a Langendorff apparatus to estimate baseline aortic flow (AF), coronary flow (CF), cardiac out-put (CO), heart rate (HR), systolic pressure (SP), aortic mean pressure, and the rate-pressure product (RPP). The hearts were divided into four groups: group 1, 8-hr storage in UW solution; groups 2 and 3, 8- or 12-hr storage in HTK solution, respectively; and group 4, 12-hr storage in HTK solution with NCR. They were arrested and stored at 4 degrees C in each preservation solution. Following storage, they were reperfused and postpreservative function was measured to assess cardiac functional recovery. Concentrations of creatine phosphokinase, troponin-T, and lactate in the coronary perfusate were measured. Frozen tissue samples from groups 3 and 4 were analyzed for adenylate content and cGMP. The myocardial water content was also measured. The recovery of AF, CF, CO, SP, and RPP in group 2 was significantly improved compared with that in group 1 (P<0.05). The recovery of AF, CF, CO and HR in group 4 was significantly better than that in group 3 (P<0.05). Creatine phosphokinase leakage in group 2 and troponin-T leakage in group 4 were significantly reduced (P<0.05 vs. groups 1 and 3, respectively). Total adenine nucleotides and the adenylate energy charge in group 4 were well sustained (P<0.05 vs. group 3). These results suggest that HTK solution is more effective than UW solution for cardiac preservation, and that NCR provides still better protection.

Comparative genome mapping of the ataxia-telangiectasia region in mouse, rat, and Syrian hamster

Chromosomal locations of the Atm (ataxia-telangiectasia (AT)-mutated) and Acat1 (mitochondrial acetoacetyl-CoA thiolase) genes in mouse, rat, and Syrian hamster were determined by direct R-banding FISH. Both genes were colocalized to the C-D band of mouse chromosome 9, the proximal end of q24.1 of rat chromosome 8, and qa4-qa5 of Syrian hamster chromosome 12. The regions in the mouse and rat were homologous to human chromosome 11q. Fine genetic linkage mapping of the mouse AT region was performed using the interspecific backcross mice. Atm, Acat1, and Npat, which is a new gene isolated from the AT region, and 12 flanking microsatellite DNA markers were examined. No recombinations were found among the Atm, Npat, Acat1, and D9Mit6 loci, and these loci were mapped 2.0 cM distal to D9Mit99 and 1.3 cM proximal to D9Mit102. Comparison of the linkage map of mouse chromosome 9 (MMU9) and that of human chromosome 11 (HSA11) indicates that there is a chromosomal rearrangement due to an inversion between Ets1 and Atm-Npat-Acat1 and that the inversion of MMU9 originated from the chromosomal breakage at the boundary between Gria4 and Atm-Npat-Acat1 on HSA11. This type of inversion appeared to be conserved in the three rodent species, mouse, rat, and Syrian hamster, using additional comparative mapping data with the Rck gene.

P2u purinoceptor regulation of mucin secretion in SPOC1 cells, a goblet cell line from the airways

The SPOC1 cell, a novel goblet cell line derived from rat trachea, was tested for its ability to exhibit regulated mucin secretion in response to purinergic (P2) agonists. High-molecular mass glycoconjugates (HMMGs) purified by CsCl-density-gradient centrifugation had a buoyant density of 1.45 g/ml. The purified HMMG material exhibited a single major band with an apparent molecular mass of greater than 1000 kDa in SDS/ polyacrylamide gels stained with silver or blotted and stained with soya-bean agglutinin. [3H]HMMG was resistant to proteoglycan-degrading enzymes, but was susceptible to neuraminidase. The HMMG was approx. 91% carbohydrate by weight, and the glycosides were O-linked. The HMMG amino acid composition was enriched in Ser and Thr (sum 27%). Thus SPOC1-cell HMMG possess the characteristics of mucin. Mucin secretion by SPOC1 cells, grown on permeable supports and perfused luminally, was stimulated by ATP, UTP and adenosine 5'-[gamma-thio]triphosphate (100 microM) 4-5-fold over a baseline of 4 ng/min. The three dose-effect relations were nearly identical (K0.5 approximately 4 microM). SPOC1 cells grown on plastic and rat tracheal epithelial primary cells responded similarly to ATP and/or UTP. SPOC1 cells failed to respond to other purinergic agonists, either luminally or serosally, and consequently seem to possess an apical membrane P2u purinoceptor. SPOC1-cell total RNA was probed for P2u purinoceptor mRNA. Using conserved primers for both reverse transcriptase and PCR, a single band of the predicted size was observed, which had a nucleotide base sequence identical with the rat P2u purinoceptor mRNA. Thus SPOC1 cells secrete mucin under the control of a P2u purinoceptor; they should prove useful in dissecting the associated cellular regulatory pathways.

Pyridoxine deficiency affects biomechanical properties of chick tibial bone

The mechanical integrity of bone is dependent on the bone matrix, which is believed to account for the plastic deformation of the tissue, and the mineral, which is believed to account for the elastic deformation. The validity of this model is shown in this study based on analysis of the bones of vitamin B6-deficient and vitamin B6-replete chick bones. In this model, when B6-deficient and control animals are compared, vitamin B6 deficiency has no effect on the mineral content or composition of cortical bone as measured by ash weight (63 +/- 6 vs. 58 +/- 3); mineral to matrix ratio of the FTIR spectra (4.2 +/- 0.6 vs. 4.5 +/- 0.2), line-broadening analyses of the X-ray diffraction 002 peak (beta 002 = 0.50 +/- 0.1 vs. 0.49 +/- 0.01), or other features of the infrared spectra. In contrast, collagen was significantly more extractable from vitamin B6-deficient chick bones (20 +/- 2% of total hydroxyproline extracted vs. 10 +/- 3% p < or = 0.001). The B6-deficient bones also contained an increased amount of the reducible cross-links DHLNL, dehydro-dihydroxylysinonorleucine, (1.03 +/- 0.07 vs. 0.84 +/- 0.13 p < or = 0.001); and a nonsignificant increase in HLNL, dehydro-hydroxylysinonorleucine, (0.51 +/- 0.03 vs. 0.43 +/- 0.03, p < or = 0.10). There were no significant changes in bone length, bone diameter, or area moment of inertia. In four-point bending, no significant changes in elastic modulus, stiffness, offset yield deflection, or fracture deflection were detected. However, fracture load in the B6-deficient animals was decreased from 203 +/- 35 MPa to 151 +/- 23 MPa, p < or = 0.01, and offset yield load was decreased from 165 +/- 9 MPa to 125 +/- 14 MPa, p < or = 0.05. Since earlier histomorphometric studies had demonstrated that the B6-deficient bones were osteopenic, these data suggest that although proper cortical bone mineralization occurred, the alterations of the collagen resulted in changes to bone mechanical performance.

Valve replacement with the CarboMedics bileaflet mechanical prosthesis: clinical results at midterm

OBJECTIVE

We study the clinical midterm results of the valve replacement with the CarboMedics bileaflet mechanical prosthesis. EXPERIMENTAL DESIGN AND SETTING: Retrospective study. Institutional practice (National Cardiovascular Center, Osaka, Japan).

PATIENTS AND INTERVENTIONS

167 CarboMedics prostheses were implanted in 144 patients from April, 1990 and December, 1993. Of these, 77 patients underwent isolated aortic valve replacement (AVR), 45 patients underwent isolated mitral valve replacement (MVR), 21 patients underwent double (aortic and mitral) valve replacement (DVR), and one patient underwent triple (aortic, mitral and tricuspid) valve replacement (TVR).

MEASURES

Events were defined in accordance with the guidelines for reporting morbidity and mortality after cardiac valve operations of the Society of Thoracic Surgeons/American Association for Thoracic Surgery.

Identification and characterization of a new gene physically linked to the ATM gene

Ataxia telangiectasia (AT) is an autosomal recessive disease of unknown etiology associated with cerebellar ataxia, oculocutaneous telangiectasia, immunodeficiency, and hypersensitivity to ionizing radiation. Although AT has been divided into four complementation groups by its radioresistant-DNA synthesis phenotype, the ATM gene has been isolated as the candidate gene responsible for all AT groups. We identified a new gene, designated NPAT, from the major AT locus on human chromosome 11q22-q23. The gene encoded a 1421-amino-acid protein containing nuclear localization signals and phosphorylation target sites by cyclin-dependent protein kinases associated with E2F. The messenger RNA of NPAT was detected in all human tissues examined, and its genomic sequence was strongly conserved through eukaryotes, suggesting that the NPAT gene may be essential for cell maintenance and may be a member of the housekeeping genes. Analysis of the genomic region of NPAT surprisingly revealed that the gene existed only 0.5 kb apart from the 5' end of the ATM transcript with opposite transcriptional direction. It may be possible to propose the idea that the promoter region could be shared by both housekeeping genes and that each gene could influence the expression of the other.

Developmental changes in skin collagen biosynthesis pathway in posthatch male and female chickens

The developmental changes in skin collagen biosynthesis pathway in male and female chickens were evaluated. Concentration of collagen, levels of mRNA for collagen type I subunits and for lysyl hydroxylase, and the level of three lysyl oxidase-derived cross-links: dehydro-dihydroxylysinonorleucine (DHLNL), dehydro-hydroxylysinonorleucine (HLNL), and dehydro-histidinohydroxymerodesmosine (HHMD) were determined during 4 wk posthatching. Skin collagen content increased with age and was higher in males than in females. In both sexes, the expression of the genes coding for alpha 1 and alpha 2 of collagen type I decreased with age: alpha 1(I) gene expression decreased from Day 3 onwards, whereas the reduction in alpha 2(I) gene expression started 1 wk later. At all ages examined, the expression of both genes was higher in male than in female skin. Males and females lysyl hydroxylase gene expression remained low until Day 16, after which an increase in the enzyme gene expression was observed. An increase in skin HLNL content was observed from Day 3 in both sexes reaching a peak in males at Day 9 and in females 1 wk later. The DHLNL content, which was higher in males than in females at all ages tested, dramatically decreased in both male and female skin from 3 d of age, reaching its lowest level at Day 16, and remained at that low level thereafter. The skin content of HHMD in males and females followed an oscillatory behavior with higher peaks in the male skin. The results suggest that the higher tensile strength of male skin than female skin may be due to the elevated skin collagen content that resulted from increased expression in collagen type I genes on the one hand, and from the higher amounts of various collagen cross-links on the other.

Induction of tissue transglutaminase in rat superior cervical sympathetic ganglia following in vitro stimulation of retinoic acid

The addition of retinoic acid (RA, 50 nM) to Dulbecco's modifed Eagle's medium containing 1.0 percent bovine serum albumin and 50 mu g/l of gentamicin markedly increased the activity of a Ca(2+) -dependent tissue transglutaminase (TGase) (ca. 3.2-fold), which stabilizes newly formed protein assemblies at the sites of synapses, in isolated rat superior cervical sympathetic ganglia (SCG), which is abundant in synapses, following in vitro aerobic incubation for 3 h at 37 degrees C. An isomer of RA, 13-cis-RA (50 nM), showed the same tendency but rather lesser magnitude (ca. 1.7-fold) in ganglionic TGase activation. Also, retinal (50 nM), a precursor of RA, had a little effect on TGase stimulation (ca. 1.5-fold) in SCG. The RA-induced enhancement of ganglionic TGase activity was completely eliminated in the presence of either actinomycin D (1.0 mu g/ml), a depressant of molecular transcriptional activity, or a potent inhibitor of protein synthesis, cycloheximide (10 mu g/ml). Kinetic analyses show that the stimulation of ganglionic TGase activity evoked by RA addition was associated with only an increase in V max value (ca. 3.3-fold) without change in Km value. Thus, the enzyme protein of TGase might be synthesized de novo in the ganglia in response to RA. The RA-induced activation effect of ganglionic TGase almost disappeared (ca. 1.3-fold) 1 week following denervation, by which time preganglionic cholinergic nerve terminals were degradated. In axotomized SCG, where sympathetic neurons were degenerated and reactive proliferation of glial cells was in progress, the RA-evoked increase in ganglionic TGase activity was attenuated (ca. 1.3-fold). These findings imply that some retinoids, especially RA effectively participate in the cholinergic potentiation of synaptic activity.