Activity-dependent distribution of protein kinase C-delta within rat cerebellar Purkinje cells following unilateral labyrinthectomy

Protein kinase C isoforms PKC-delta and PKC-gamma are expressed in Purkinje cells in the uvula-nodulus of the cerebellum. We examined the effect of Purkinje cell activity on the transcription, expression and intracellular distribution of PKC-delta and PKC-gamma. Relative changes in activity were induced by unilateral labyrinthectomy (UL), decreasing the activity of Purkinje cells on the side of the labyrinthectomy relative to the contralateral side with intact vestibular input. After a UL, there was decreased immunolabeling of Purkinje cell axon terminals in the ipsilateral caudal vestibular complex by antisera to PKC-delta, but not PKC-gamma. Western blots prepared from the uvula-nodulus and caudal vestibular complex showed an increase in the cytosolic PKC-delta and a decrease in membrane-associated PKC-delta in the ipsilateral uvula-nodulus 12-48 h after the UL. Hybridization histochemistry and semiquantitative reverse transcription polymerase chain reaction (RT-PCR) demonstrated no change in transcription of PKC-delta mRNA in the uvula-nodulus 1-240 h after unilateral labyrinthectomy. We conclude that both PKC-delta and PKC-gamma are constitutively expressed in Purkinje cells. The targeting of PKC-delta, but not PKC-gamma, to Purkinje neuron synaptic terminals is influenced by activity.

Oleoyl-CoA is the major de novo product of stearoyl-CoA desaturase 1 gene isoform and substrate for the biosynthesis of the Harderian gland 1-alkyl-2,3-diacylglycerol

1-Alkyl-2,3-diacylglycerol (ADG) is a unique neutral lipid found in the eyeball-associated Harderian gland (HG) of the mouse and acts as a lubricant to facilitate eyelid movement. We found that the HG of the mice with a disruption in the gene for stearoyl-CoA desaturase 1 (SCD1) (SCD1-/-) is deficient in ADG. The amount of C20:1n-9, which is a major fatty acid of ADG, was reduced by greater than 90% despite normal elongase enzyme activity proposed to elongate it from C18:1n-9. HG from SCD1-/- mice exhibited high desaturase activity toward C16:0-CoA as substrate but had very low desaturase activity toward C18:0-CoA. Feeding diets containing high levels of oleate to the SCD1-/- mice did not increase the levels of C18:1n-9 or C20:1n-9 in the HG and failed to restore the ADG to the levels found in the HG of the wild-type mouse. De novo ADG synthesis as measured by the incorporation of [(3)H]glycerol and [(14)C]glucose was high in the SCD1+/+ mouse but was reduced by greater than 90% in the HG of SCD1-/- mouse. The deficiencies in the levels of ADG and C20:1n-9 were not compensated for by the expression of SCD2 and SCD3 isoforms in the HG of the SCD1-/- mouse. These observations demonstrate that SCD1-synthesized oleoyl-CoA is a major substrate required for the biosynthesis of normal levels of ADG and that the SCD isoforms present in the HG have different substrate specificity.

Development of a method for the determination of human skin moisture using a portable near-infrared system

In this study, a portable near-infrared (NIR) system was newly integrated with a photodiode array detector that has no moving parts, and this system has been successfully applied for the evaluation of human skin moisture. The good correlation between NIR absorbance and the absolute water content of separated hairless mouse skin, in vitro, was showed, depending on the water content (7.4-84.9%) using this portable NIR system. Partial least squares (PLS) regression was used for calibration with the 1150-1650-nm wavelength range. For practical use for the evaluation of human skin moisture, the PLS model for human skin moisture was developed in vivo using the portable NIR system on the basis of the relative water content values of stratum corneum from the conventional capacitance method. The PLS model showed a good correlation. This study indicated that the portable NIR system, as compared to conventional methods, could be a powerful tool for human skin moisture, which may be much more stable to environmental conditions, such as temperature and humidity. Furthermore, to confirm the performance of the newly integrated portable NIR system, a scanning-type conventional NIR spectrometer was used in the same experiments, and the results were compared.

Observation of B --> J/psi K(1)(1270)

We report the first observation of the exclusive decay process B-->J/psi K(1)(1270) using a sample of 11.2M BB macro meson pairs collected in the Belle detector at the KEKB asymmetric energy e(+)e(-) collider. We measure branching fractions of B[B(0)-->J/psi K(0)(1)(1270)] = (1.30+/-0.34+/-0.32) x 10(-3) and B[B(+)-->J/psi K(+)(1)(1270)] = (1.80+/-0.34+/-0.39) x 10(-3), where the first error is statistical and the second is systematic. These modes constitute approximately 15% of the total number of B-->J/psi X decays. No evidence is seen for B-->J/psi K(1)(1400) and we set an upper limit for this branching fraction.

A facile, stereoselective [2 + 2] photoreaction mediated by curcurbit[8]uril

The [2 + 2] photoreaction of (E)-diaminostilbene dihydrochloride proceeds with large rate acceleration and high stereoselectivity via formation of a stable 1:2 host-guest complex with curcurbit[8]uril in solution.

Retinoid-dependent antagonism of serum response factor transactivation mediated by transcriptional coactivator proteins

Transcriptional coactivators SRC-1 and p300 specifically interact with liganded-nuclear receptors and also modulate other transcription factors, including serum response factor (SRF). Here, we report that retinoids repress transactivation by SRF and specific interactions exist between the DNA binding domains of SRF and retinoic acid and retinoid X receptors. We further demonstrate that the repression may involve retinoid-dependent competition for a limiting amount of SRC-1 and p300 between SRF and retinoid receptors. We propose that the well-defined anti-proliferative action of retinoids could, at least in part, result from this novel transrepressive action on the mitogenic transcription factor SRF.

Characterization of mutations, including a novel regulatory defect in the first intron, in Bruton's tyrosine kinase gene from seven Korean X-linked agammaglobulinemia families

In this report, we describe seven mutations, including a novel single base pair substitution in intron 1, of the Bruton's tyrosine kinase (Btk) gene found in 12 Korean patients with X-linked agammaglobulinemia. Various mutations, including three novel genetic alterations, were discovered using single-strand conformation polymorphism analysis and direct DNA sequencing. The effect of the intron 1 point mutation (intron 1 +5G-->A) was further evaluated using reporter constructs. Using luciferase assay experiments, we showed that the transcriptional activity of the mutant was significantly lower than in normal counterparts, indicating that the intronic mutation was functional. In addition, DNase I footprinting analysis showed that a single protected region spanning the position +3 to +15 bp hybridized with a mutant-specific probe, but not with a wild-type probe. EMSA indicated that a distinct nuclear protein has the ability to bind the mutant oligonucleotides to produce a new DNA-protein complex. We also observed decreased expression of Btk proteins in monocytes of patients having the point mutation in intron 1. Taken together with the functional analysis, our results strongly suggest the existence of a novel cis-acting element, which might be involved in the down-regulation of Btk gene transcription. Precise definition of the regulatory defect in the Btk intron 1 may provide valuable clues toward elucidating the pathogenesis of X-linked agammaglobulinemia.

DNA-based genotyping techniques for the detection of point mutations associated with insecticide resistance in Colorado potato beetle Leptinotarsa decemlineata

Three DNA-based genotyping techniques, bi-directional PCR amplification of specific allele (bi-PASA), single-stranded conformational polymorphism (SSCP) and minisequencing, have been developed and compared for the detection of the S291G (insensitive acetylcholinesterase) and L1014F (insensitive sodium channel) mutations associated with azinphos-methyl and permethrin resistance, respectively, in the Colorado potato beetle (Leptinotarsa decemlineata). Extraction of genomic DNA from individual neonates that were hatched from previously collected egg masses is the most efficient and reliable means to obtain suitable templates in terms of convenience, economy, speed and DNA quality. Bi-PASA, employing two allele-specific primers, appears to be the most efficient and rapid genotyping method for the simultaneous detection of both resistant/susceptible homozygous (SS, RR) and heterozygous (SR) alleles. Its resolution, however, is strongly dependent on the quality of template genomic DNA. SSCP also allows unambiguous genotyping, including the detection of heterozygous alleles, and is less dependent on template DNA quality, but requires a longer processing time. Minisequencing is amenable to a 96-well microtiter plate format for the processing of a large number of samples and allows direct detection of resistant/susceptible homozygous alleles but is not as efficient as the PASA and SSCP in detecting heterozygous alleles. In considering the advantages and disadvantages of each technique, DNA-based genotyping is best employed in combinations, with the bi-PASA as the primary method and the SSCP and minisequencing as the secondary validating methods. These methods are rugged, rapid, cost-effective and capable of resolving SS, RR and SR individuals. The availability of such DNA-based genotyping techniques, using neonate genomic DNA as templates, will enable the precise monitoring of the resistant and susceptible allele frequencies, including those of heterozygote individuals, in field populations of L. decemlineata.

Anomalous crossover behavior at finite temperature

We introduce a stochastic growth model where the growth is controlled by a temperaturelike parameter T. The model shows various types of dynamical behavior as T changes from 0 to infinity. For T=0 the growth process belongs to the quenched Kardar-Parisi-Zhang (KPZ) universality class, whereas it belongs to the Edwards-Wilkinson (EW) universality class for T=infinity. In the intermediate range 0<T<infinity, the model shows an anomalous crossover behavior from the quenched KPZ to the thermal KPZ class. The KPZ nonlinearity is generated by an anisotropic effect of the quenched noise which exists only for T<infinity in our model. We also study crossovers between different types of scaling behavior of the interface width for various T's.

Effect of head rotation on lateral cephalometric radiographs

The purpose of this study was to identify the potential projection errors of lateral cephalometric radiographs due to head rotation in the vertical Z-axis. For this investigation, 17 human dry skull samples with permanent dentition were collected from the Department of Anatomy in the College of Medicine, Chosun University. They had no gross asymmetry and were well preserved. Each dry skull was rotated from 0 degrees to +/- 15 degrees at 1 degrees intervals. A vertical axis, the Z-axis, was used as a rotational axis to have 527 lateral cephalometric radiographs exposed. The findings were that: (1) angular measurements have fewer projection errors than linear measurements; (2) the greater the number of landmarks on the midsagittal plane that are included in angular measurements, the fewer the projection errors occurring; (3) horizontal linear measurements decrease gradually in length as the rotational angle toward the film increases, whereas a small increase and then decrease of the length occurs as the rotational angle toward the focal spot increases; (4) horizontal linear measurements have more projection errors than vertical linear measurements according to head rotation; and (5) projection errors of vertical linear measurements increase as the distance from the rotational axis increases. In summary, angular measurements of lateral cephalometric radiographs are more useful than linear measurements in minimizing the projection errors associated with head rotation on a vertical axis.

Selection of a potential probiotic Lactobacillus strain and subsequent in vivo studies

The probiotic potential of a Lactobacillus strain, isolated from pig faeces, was assessed as a probiotic in piglets. The strain was examined for resistance to pH 2.0, 0.5% oxgall and antibiotics, and antimicrobial activities against enteric pathogenic bacteria. The probiotic strain, L. reuteri BSA131, was administered through the feed to 25 1-month-old Landrace piglets. The piglets were divided into five groups of five piglets each and fed with different diets for 28 days. The daily consumption of L. reuteri BSA131 was assigned into two groups by the concentration of 10(6) or 10(8) freeze-dried bacteria. Fecal samples were collected before, during, and after consumption. Lactobacilli and enterobacteria cell counts were determined in the fecal samples. The liveweight gains and feed consumption of the piglets were recorded daily. This study showed that strain BSA131 enhanced liveweight gains and feed conversion rates in piglets. It also showed a significant increase in lactobacilli cell counts and decreases in enterobacterial numbers in the fecal samples. Strain BSA131 was considered to be a potential probiotic for piglets, especially after weaning.

Higher incidence of p53 mutation in cervical carcinomas with intermediate-risk HPV infection

OBJECTIVE

Inactivation of p53, either through mutation or interaction with human papillomavirus (HPV) E6 oncoprotein, is a characteristic feature of cervical carcinoma cell lines that have been previously studied. To elucidate the role of p53 in the carcinogenesis of Korean cervical carcinomas, 27 HPV-positive and 13 HPV-negative cervical carcinomas were studied in order to evaluate the status of the p53 gene.

STUDY DESIGN

The HPV status was ascertained by polymerase chain reaction (PCR) amplification using consensus primers designed from the E6 and E7 open reading frames (ORFs). The p53 mutation status was analyzed by direct sequencing of the PCR product in highly conserved exons 5-8.

RESULTS

There was no significant difference in the frequency of the p53 mutation between the HPV-positive and negative cases. All three mutations in the HPV-positive cases were associated with intermediate-risk viruses. The average age of the patients with the p53 mutation was 14 years older than that of patients without the p53 mutation.

CONCLUSION

p53 mutations are higher in the so called intermediate-risk HPV positive than HPV 16 or 18 positive cervical carcinomas.

Modulation of cytochrome P4501-mediated bioactivation of benzo[a]pyrene by volatile allyl sulfides in human hepatoma cells

Allyl sulfides such as diallyl sulfide (DAS), diallyl disulfide (DADS), and diallyl trisulfide (DATS), typical flavor components of Allium vegetables, have been shown to inhibit benzo[a]pyrene (B[a]P)-induced carcinogenesis in animal models. As a possible mechanism of this inhibition, the effect of these volatile substances on cytochrome P450 (CYP)1 (CYP1A1, 1A2 and 1B1)-mediated bioactivation of B[a]P was investigated using a human hepatoma cell model (HepG2). DADS and DATS inhibited the B[a]P-induced ethoxyresorufin O-deethylase (EROD) activity, a marker enzyme for CYP1, by 30-90% and 70-95% at 100-1,000 microM concentration, respectively. The cell viability, an indicator of the capacity to inhibit B[a]P bioactivation, was increased by treatments of 100-1,000 microM DADS and 10-100 microM DATS. Immunoblot results indicated that the B[a]P inducible CYP1A2 protein was suppressed by 100-1,000 microM of DADS and 10-100 microM of DATS, but CYP1A1 and 1B1 were not detectable in any microsomes. Analysis of B[a]P metabolites revealed that the level of 7,8-diol formed was significantly reduced in the DADS and DATS treated microsomes as compared to the control. The level of 9,10-diol and 4,5-diol formed was also lowered by the allyl sulfide treatments. These results suggest that the protective mechanism of allyl sulfides on B[a]P-induced carcinogenesis is possibly related with the modulation of CYP1-mediated bioactivation of B[a]P.

Regulation of apoptosis by somatostatin and substance P in peritoneal macrophages

Recent studies have shown that somatostatin (SOM) inhibits interleukin 6 (IL-6) and interferon gamma (IFNgamma) production by lymphocytes and peritoneal macrophages, whereas substance P (SP) enhances these cytokines production. To define the mechanism of the cytokine production enhancements and inhibitions by SOM and SP, we examined the expression of apoptosis modulator, p53, Bcl-2, Bax, inducible nitric oxide synthase (iNOS), Fas, caspase-8 and nitric oxide (NO) in thioglycolate-elicited peritoneal macrophages. SOM caused up-regulation of p53, Bcl-2, Fas and caspase-8 activities, and down-regulation of iNOS expression and NO production. On the other hand, SP slightly induces p53 and highly induces Bcl-2, iNOS expression and NO production. These data suggest that apoptosis by SOM may occur by a Bax- and NO-independent p53 accumulation, and through Fas and caspase-8 activation pathways, and that the inducible expression of Bcl-2 and NO production by SP may contribute to prevent the signals of apoptosis by Bax, and via Fas and caspase-8 activation.

Bax-dependent apoptosis induced by ceramide in HL-60 cells

Ceramide is an important lipid messenger involved in mediating a variety of cell functions including apoptosis. In this study, we show that antisense bax inhibits cytochrome c release, poly(ADP-ribose)polymerase cleavage and cell death induced by ceramide in HL-60 cells. In addition, ceramide induces translocation of Bax to mitochondria. The addition of the broad spectrum caspase inhibitor zVAD-fmk prevented ceramide-induced apoptotic cell death but did not inhibit translocation of Bax and mitochondrial cytochrome c release. Furthermore, ceramide inhibits the expression of the antiapoptotic protein Bcl-xL with an increase in the ratio of Bax to Bcl-xL. These data provide direct evidence that Bax plays an important role in regulating ceramide-induced apoptosis.

Observation of Cabibbo suppressed B --> D(*)K- decays at Belle

We report observations of the Cabibbo suppressed decays B-->D((*))K- using a 10.4 fb(-1) data sample accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB e(+)e(-) storage ring. We find that the ratios of Cabibbo suppressed to Cabibbo favored branching fractions are B(B--->D0K-)/B(B--->D0pi(-)) = 0.079+/-0.009+/-0.006, B(B(0)-->D+K-)/B(B(0)-->D+pi(-)) = 0.068+/-0.015+/-0.007, B(B--->D(*0)K-)/B(B--->D(*0)pi(-)) = 0.078+/-0.019+/-0.009, and B(B(0)-->D(*+)K-)/B(B(0)-->D(*+)pi(-)) = 0.074+/-0.015+/-0.006. These are the first observations of the B-->D+K-, D(*0)K-, and D(*+)K- decay processes.

High-resolution genetic and physical mapping of modifier-of-deafwaddler (mdfw) and Waltzer (Cdh23v)

Modifier-of-deafwaddler (mdfw) and waltzer (Cdh23v) are loci on mouse chromosome 10 encoding factors that are essential for the function of auditory hair cells. The BALB/cByJ-specific mdfw allele encodes a necessary and sufficient modifier that induces progressive early onset hearing loss in CBy-dfw2J heterozygotes. Recessive mutations in the waltzer locus result in circling behavior and congenital deafness. In this report we present a high-resolution integrated genetic and physical map of mdfw and Cdh23(v). Our genetic analyses localize mdfw between markers D10Mit60 and 148M13T7 within a 1.01-cM region. The Cdh23v critical interval is fully contained within the mdfw region and localizes between markers 146O23T7 and 148M13T7 within a 0.35-cM interval that is represented in an approximately 500-kb BAC contig. Our data suggest that mdfw and Cdh23v are allelic.

Involvement of oxidative stress in experimentally induced reflux esophagitis and Barrett's esophagus: clue for the chemoprevention of esophageal carcinoma by antioxidants

Oxidative damage has long been related to mucosal damages of gastrointestinal tracts and their ensuing carcinogenesis. In spite of treatment with anti-secretory medications for reflux esophagitis, considerable portions of patient did not achieve the complete mucosal healings or suffered from sustaining symptoms or development of dread complication like Barrett's esophagus, suggesting other damaging factors or impaired mucosal resistance are also involved in their pathogenesis. The present study was designed either to evaluate the oxidative stress as the major pathogenic factor of reflux esophagitis or to find out the usefulness of antioxidant in the treatment of reflux esophagitis and the prevention of development of Barrett's esophagus. Acute or chronic reflux esophagitis was induced through either narrowing the third portion of duodenal lumen or performing myotomy of lower esophageal sphincter in rats, respectively. DA-9601, a new phytopharmaceutical possessing antioxidative properties, significantly attenuated the gross and histopathologic scores of acute reflux esophagitis in a dose-dependent manner compared to those treated with ranitidine alone. Only scattered erosions were observed in antioxidant pre-treated group, but acid suppression by ranitidine was not so effective in decreasing the severity of reflux esophagitis. Significantly increased amounts of malondialdehyde (MDA), increased NF-kappa B activations, and depletions of reduced glutathione (GSH) were observed in experimentally induced reflux esophagitis, but DA-9601 pre-treatment attenuated the decrement of mucosal GSH levels and decreased MDA formations significantly. DA-9601 treatment showed significant reductions in the activation of NF-kappa B transcription factor. DA-9601 significantly decreased the proliferating cell nuclear antigen-labeling index (PCNA-LI) of esophagus (P<0.05) in chronic reflux esophagitis model and prevented the development of Barrett's esophagus. In conclusion, reflux esophagitis provoked considerable levels of oxidative stress in the esophageal mucosa. Antioxidant treatment seems to be the first line therapeutics in the prevention or treatment of reflux esophagitis. Moreover, antioxidant possibly played the chemopreventive role through preventing the development of Barrett's esophagus.

Incomplete pancreas divisum: is it merely a normal anatomic variant without clinical implications?

BACKGROUND AND STUDY AIMS

Incomplete pancreas divisum (PD) has been generally regarded as merely a normal anatomic variant, without clinical implications. This study compares the prevalence, symptom occurrence rate, clinical presentation, and outcomes of endoscopic treatment in patients with incomplete PD and those with complete PD.

PATIENTS AND METHODS

The study population consisted of 56 patients (27 with complete PD and 29 with incomplete PD), identified from 4473 newly performed endoscopic retrograde cholangiopancreatography examinations. Endoscopic treatment (minor papilla sphincterotomy with stents or nasopancreatic drainage tube insertion) was attempted in 25 symptomatic patients with PD, which was suspected to be causing the associated pancreatic diseases: acute recurrent pancreatitis (ARP) (n = 13; five patients with complete PD and eight with incomplete PD); chronic pancreatitis (CP) (n = 10: five patients with complete PD and five with incomplete PD); and pancreatic-type pain (PP) (n = 2; one patient with complete PD and one with incomplete PD). The mean follow-up period was 17 months (range 9 - 49 months).

RESULTS

In 12 of the 27 patients with complete PD--six with ARP, five with CP, and one with PP--it was suspected that PD was the cause of pancreatic disease. Ten of the 11 symptomatic patients with complete PD underwent successful endoscopic treatment (five with endoscopic minor papilla sphincterotomy and stenting, and five with endoscopic minor papilla sphincterotomy and endoscopic nasopancreatic drainage), and seven of these ten patients benefited from the endoscopic treatment. In 14 of the 29 patients with incomplete PD--eight with ARP, five with CP, and one with PP--it was suspected that pancreas divisum was the cause of pancreatic disease. Thirteen of the 14 symptomatic patients with incomplete PD underwent successful endoscopic treatments (six with endoscopic minor papilla sphincterotomy and stenting, and seven with endoscopic minor papilla sphincterotomy and endoscopic nasopancreatic drainage), and eight of these 13 patients experienced clinical improvement.

CONCLUSIONS

The prevalence rate, symptom occurrence rate, clinical presentation, and outcomes of endoscopic treatment were similar in patients with complete PD and incomplete PD. Incomplete PD may therefore have similar clinical implications to those of complete PD.

Bilateral selective internal mammary artery angiography via right radial approach: clinical experience with newly designed Yumiko catheter

The radial artery has been increasingly used as a primary access site for coronary angiography and intervention. But the technique for internal mammary artery (IMA) visualization via the right radial artery has not been well described. Therefore, the study was conducted to investigate the feasibility, safety, and adequacy of selective bilateral IMA angiography via the right radial artery using the recently developed Yumiko catheter. From November 1999 to October 2000, both IMA angiographies were undertaken immediately following the diagnostic coronary angiogram taken from right transradial approach in 114 patients. IMA angiography was successfully obtained in 99% (113/114) patients. For left IMA angiography, 73 (64%), 28 (25%), and 12 (11%) imagings were obtained in a selective, a semiselective, and a nonselective way, respectively. After initial periods of 33 left-IMA-only imaging, right IMA angiography was obtained in 81 patients (phase 2). Selective right IMA imaging was done in 73 (90%), semiselective in 6, and nonselective in 2 patients. The reasons for failure of selective or semiselective visualization were severe vascular tortuosity, far distal anatomical origin of left IMA and ulcerative plaque, or acutely angled left subclavian artery. The feasibility and safety of selective and semiselective bilateral IMA angiography were demonstrated using a 5 Fr Yumiko catheter from the right radial approach. Cathet Cardiovasc Intervent 2001;54:19-24.

Transmission of Mycobacterium tuberculosis among high school students in Korea

SETTING

Screening of pulmonary tuberculosis (PTB) patients from high school students by chest radiography and sputum examination.

OBJECTIVE

To investigate transmission of Mycobacterium tuberculosis among high school students.

DESIGN

The restriction fragment length polymorphism (RFLP) profiles of M. tuberculosis isolated from PTB patients of high school students were analysed.

RESULTS

Clustering cases were found in PTB patients screened among high school students. During this study, a single strain with a particular RFLP profile was found most frequently. This particular strain was also the one that was found to be most prevalent among Korean clinical isolates of M. tuberculosis during a nationwide TB prevalence survey previously done in 1995. This strain seems to be the most widely distributed one in Korea, and has thus been designated K1. In addition, by close examination of the RFLP profiles, it was also found that there existed 34 isolates that had RFLP profiles that were similar to the K1 strain. Therefore, K1 and K1-related strains (18.4% of strains, designated as the K family) seem to comprise the most dominant M. tuberculosis strains present in Korea.

CONCLUSION

Clustering cases were found in PTB patients screened among high school students in Korea. The K family was found to be most prevalent among the clinical isolates of M. tuberculosis found.

Nicotine alters the usual reciprocity between meal size and meal number in female rat

Tobacco smoking reduces appetite and body weight (BW). Cessation of smoking leads to hyperphagia and weight gain. Daily food intake (FI) is a function of meal number (MN) and meal size (MZ), i.e., FI=MNxMZ. Under normal conditions, the female Fischer rat has a periodic reciprocal fluctuation between MZ and MN corresponding to phase of estrous cycle. Wide fluctuations between MZ and MN compensate each other to keep FI constant. Nicotine (5 mg/kg BW/day) was infused via osmotic minipump for 7 days. Controls received saline. FI, MZ, and MN were measured by an Automated Computerized Rat Eater Meter. Nicotine significantly decreased BW and FI via a decrease in MZ without compensatory increase of MN. Nicotine cessation led to hyperphagia, normalizing BW loss via an increase in MZ, which exceeded a compensatory decrease in MN. Nicotine significantly prolonged the estrous cycle by an extension of proestrous phase. Nicotine significantly lengthened the intermeal interval (IMI), delaying the start of the next meal and simultaneously decreasing subsequent MZ. Stopping nicotine led to normalization of IMI and MZ. Data show that nicotine alters the usual reciprocal regulation between MZ and MN and leads to a prolongation of the estrous cycle.

Differential cell death induced by salsolinol with and without copper: possible role of reactive oxygen species

Salsolinol (SAL), a novel dopaminergic catechol tetrahydroisoquinoline neurotoxin, has been speculated to contribute to the etiology of Parkinson's disease and neuropathology of chronic alcoholism. Our previous studies have demonstrated that SAL induces strand scission in øX174 supercoiled DNA and oxidative base modification in calf thymus DNA in the presence of cupric ion. We now report that treatment of rat pheochromocytoma (PC12) cells with SAL causes reduced viability, which was exacerbated by Cu(2+). The copper chelator bathocuproinedisulfonic acid ameliorated cytotoxicity induced by SAL and Cu(2+). N-Acetyl-L-cysteine and reduced glutathione protected against SAL- plus Cu(2+)-mediated PC12 cell death. Cells exposed to SAL underwent apoptosis, as revealed by characteristic morphological and biochemical changes. SAL treatment resulted in increased levels of Bax with a concomitant decrease in expression of Bcl-x(L). Furthermore, SAL rapidly activated c-Jun N-terminal kinase, whereas the activity of extracellular signal-regulated protein kinase remained unchanged. Transfection with Bcl-x(L) or Bcl-2 led to protection against SAL-mediated PC12 cell death. Although SAL alone could cause apoptotic death in PC12 cells, cells treated with SAL together with Cu(2+) became necrotic. Cells exposed to both SAL and Cu(2+) exhibited higher levels of intracellular reactive oxygen species, malondialdehyde, and 8-oxo-7,8-dihydro-2'-deoxyguanosine than did those treated with SAL alone. These results suggest that copper accelerates redox cycling of SAL, leading to massive production of reactive oxygen species, which can divert the SAL-induced cell death to necrosis.