The vertical distribution and diversity of marine bacteriophage at a station off Southern California

Sixty-two bacteriophages were isolated on eight indigenous bacteria from a Pacific Ocean station spanning 887-m vertical depth, on two occasions between 1999 and 2000. On the basis of 16S rRNA sequences, six hosts were tentatively identified to be in the genus Vibrio and the other two were closely related to Altermonas macleodii (W9a) and Pseudoalteromonas spp. (W13a). Restriction fragment length polymorphism (RFLP) analysis of phage genomes using AccI and HapI showed that 16 phages infecting host C4a (Vibrio) displayed 14 unique RFLP patterns. However, identical phages infecting host C4b, C6a, and C6b (all Vibrio) were obtained from both the surface layer and the hypoxic zone at 850 m. Most phage isolates from the second year had a different RFLP pattern but shared genetic similarity to the phages infecting the same host from the previous year based on a hybridization study using phage genome probes. Cluster analysis of RFLP patterns and hybridization results also indicated that phages infecting the same or genetically related hosts, in general, shared higher degrees of homology in spite of the diverse RFLP patterns. Pulsed field gel electrophoresis (PFGE) analysis of native viral genomes indicated a range in genome size from less than 40 to 200 kb, and the dominant band shifted up by about 5-10 kb in the deep samples compared to the shallow ones. Hybridization of phage genome probes with total viral community DNA from various depths suggests these isolates, or at least some of their genes, represent a detectable portion of the natural viral community and were distributed throughout the water column. Thus, the results of this study demonstrated that the genetic diversity of bacteriophage in the ocean is far greater than that of their bacterial hosts. However, host range may have contributed to the evolution of the diverse phage population in the marine environment.

Macrolides: structures and microbial targets

The macrolide class of antibiotics is well established and often recommended for use in the treatment of community-acquired respiratory tract infections. A number of agents with varying antimicrobial activity have been developed via chemical modification of the core macrolide structure, a macrocyclic lactam ring. Although structurally diverse, the macrolides share a common ability to bind to the bacterial 50S ribosome subunit and inhibit protein synthesis, thereby preventing bacterial multiplication. Resistance in the clinic is due to modification of the 50S subunit in the area of the peptidyl transferase center or to an efflux pump. The newer macrolides, and in particular azithromycin, with their broad-spectrum microbiological profile have extended the therapeutic uses of this class of antibiotics and ensured that they remain an integral part of the clinician's armamentarium.

Seasonal Abundance and Distribution of Vibrio cholerae in Coastal Waters Quantified by a 16S-23S Intergenic Spacer Probe

Vibrio cholerae is the causative agent of the severe diarrheal disease cholera and is indigenous to brackish waters. To advance our understanding of the ecology of this bacterium, we have developed a molecular probing method for detection of V. cholerae in coastal waters. Water samples from 7 locations in the Newport Bay watershed, California were sampled monthly for a whole year. V. cholerae concentrations were determined by membrane filtration-colony hybridization using an oligonucleotide probe targeting the 16S-23S intergenic spacer (ITS) region. In addition to V. cholerae concentrations, environmental parameters, including temperature, salinity, total bacterial direct counts, total viable counts, and chlorophyll a concentrations, were determined for each site. V. cholerae was detected year-round throughout the watershed. Regression analysis indicated that the concentration of V. cholerae inversely correlated with salinity (p <0.001). The sampling sites located nearest to the Pacific Ocean had lower concentrations, whereas sites located along the brackish San Diego Creek (salinity 0-12 per thousand) routinely had higher concentrations. V. cholerae concentrations also correlated with temperature (p <0.01) in the watershed, with concentrations ranging from less than 1 CFU mL-1 to 2,930 CFU mL-1 of water. The results of this study indicate that the dynamics of V. cholerae is mainly influenced, out of the parameters measured, by the temperature and salinity of the environment. This information is valuable for understanding the ecology of V. cholerae.

[Endovascular treatment for peripheral arterial stenosis with endoluminal stent]

OBJECTIVE

To initially evaluate the effect and security of endovascular treatment for arterial stenosis with endoluminal stent.

METHODS

Thirty-four cases of arterial stenosis were treated with endoluminal stent from March 1999 to May 2001. The stenosis involved descending aorta (1 case), iliac artery (2), femoral artery (2), carotid artery (1), subclavian artery (2) and renal artery (1). Thiry-three cases had arteriosclerosis and one Takayasu's arteritis. Twenty-six cases were percutaneously punctured and eight cases were punctured directly.

RESULTS

All the 34 cases had the stents successfully implanted. However, one case of descending aorta stenosis died on the operation day due to rupture of the descending aorta. Dissection was performed in thirteen cases after balloon dilation and hematoma was seen at the puncturing point in eleven cases. TIA (transient ischemia attack) and cerebral infarction did not occur in the case of carotid arterial stenosis. For those with stenosis in lower extremities, ABI (ankle-brachial index) increased from 0.45 to 0.72 postoperatively. The brachial pressure of two cases of subclavian arterial stenosis returned to normal postoperatively. The blood pressure of case of renal arterial stenosis reduced from 180/120 mm Hg to 140/90 mm Hg. All the cases were followed up for one month to 26 months. Thrombosis of the arteries treated occurred in two cases of iliac arterial stenosis four and six months postoperatively.

CONCLUSIONS

The effect of endovascular treatment for arterial stenosis with endoluminal stent is satisfactory. Endovascular therapy is especially suitable for iliac arterial and limited stenosis of the subclavian artery. However, it should be cautiously used in the stenosis of the carotid artery.

Telomerase protects developing neurons against DNA damage-induced cell death

In mitotic cells, telomerase adds repeats of a DNA sequence (TTAGGG) to the ends of chromosomes (telomeres) thereby maintaining their length and preventing cellular senescence. We recently reported that the catalytic subunit of telomerase (TERT) is expressed in neuronal progenitor cells and in early postmitotic neurons in the developing rodent brain. We now report that TERT can protect cultured PC12 cells and embryonic hippocampal neurons against death induced by DNA damage. Overexpression of TERT in PC12 cells increases their resistance to the topoisomerase inhibitors camptothecin and etoposide. Hippocampal neurons in which TERT levels are decreased using antisense technology exhibit increased vulnerability to the DNA-damaging agents. Emerging findings suggest that DNA damage may trigger the death of neurons during brain development and in neurodegenerative disorders. Our data therefore suggest roles for TERT in modulating such cell deaths.

[Study on structure change and hypermethylation of p16 gene in multiple myeloma]

OBJECTIVE

To illustrate the role of structure and hypermethylation of p16 gene in the pathogenesis of multiple myeloma(MM).

METHODS

By using PCR-single strand conformation polymorphisms(PCR-SSCP) and methylation-specific PCR(MSP) techniques, the structure and hypermethylation status of p16 gene in MM cell lines and patients were analysed.

RESULTS

Homozygous deletion of p16 exon 2 was found in KM3 cells. The completely methylated p16 gene and hypermethylation of CPG island were observed in U266, LP1 cell lines and 55.56% of MM patients.

CONCLUSION

Methylation of p16 gene is important in the pathogenesis of MM and may provide a new drug target for the treatment of MM.

[Surgical treatment of abdominal aortic aneurysms: report of 482 cases]

OBJECTIVE

To improve the safety of abdominal aortic aneurysm (AAA) repair.

METHOD

The experience of 482 cases of AAA in surgical treatment and endovascular graft exclusion were reviewed from January 1960 to March 2001.

RESULTS

Retroperitoneal approach and minimal incision was used for AAA operation. New methods for control of the "neck" of aneurysm, aneurysmectomy and endovascular graft exclusion were applied. The danger of AAA repair obviously decreased. The operative mortality was 5.2% and the five-year survival rate was 74.4%.

CONCLUSION

The improvement of surgical and anesthetic techniques made AAA resection rapid and safe.

[Sixty years of museum for history of Chinese medicine]

The developmental course of museum for history of Chinese medicine can be divided into 4 stages, namely, Period of Initiation (1937-1949), Period of Development (1950-1965), Period of Stagnation (1966-1976) and Period of Rejuvenation (1977-). The article introduces the dovelopmental course of museum for history of Chinese medicine period by period, supported with plenty of historical facts.

Paget disease of the breast: analysis of 41 patients

The treatment for the patients with Paget disease of the breast is controversial. This review of its natural history, treatment approach, and clinical outcome will help to formulate treatment. Forty-one patients with a diagnosis of Paget disease of the breast were retrospectively reviewed at Providence Hospital & Medical Centers from 1980 to 1999. Ninety-eight percent of patients had underlying carcinoma (ductal carcinoma in situ and/or invasive ductal cancer). Patients with a palpable mass have a much higher incidence of invasive ductal cancer, positive lymph node, and a worse survival rate. The median length of follow-up was 42 months (range: 6--200 months). Twenty-seven percent of patients (11/41) had conservative operations, including 1 patient with a palpable mass; 10 patients with no palpable mass; and 3 patients with recurrence after conservative operation. Thirty-seven percent of patients received adjuvant therapy. Paget disease of the breast has very high incidence of underlying carcinoma (100% in a palpable mass, 96% in nonpalpable mass). Patients with a palpable mass have a worse survival than do patients with nonpalpable mass. Conservative operation should cautiously be selected even for patients with no palpable mass because of a higher recurrence rate.

Molecular markers in Paget disease of the breast

BACKGROUND AND OBJECTIVES

Molecular markers are increasingly being analyzed in tumor specimens because of their relevance to both prognosis and choice of therapy. Paget disease of the breast is an uncommon form of breast cancer, in which molecular markers have not been well characterized. The objective of this study was to investigate the expression of c-erbB-2, p53, Ki-67, Cyclin D1, Bcl-2, estrogen receptors (ER), and progesterone receptors (PR) in mammary Paget disease.

METHODS

Archival tumor tissues from 14 patients diagnosed between 1990 and 1999 with Paget disease of the breast were analyzed for these molecular markers by using an automated immunohistochemical assay. Both the intraepidermal Paget cells and the underlying carcinoma were assessed for these markers.

RESULTS

The majority of Paget cells were positive for c-erbB-2 (92.9%), Cyclin D1 (100%), and Ki-67 (85.7%), but very few were positive for Bcl-2 (14.3%). p53 was overexpressed in 42.9% of the cases, and only 28.6% were positive for ER and PR. The rate of expression of these biologic markers was similar in both the Paget cells and the underlying intraductal and/or ductal carcinoma cells.

CONCLUSIONS

Tumors from patients with Paget disease of the breast were positive for c-erbB-2, Cyclin D1, and Ki-67, molecular markers commonly associated with more aggressive tumor behavior and poorer survival in breast cancer patients. Few of these tumors expressed Bcl-2 or ER and PR, which are generally associated with a better prognosis. Similar expression of these markers in both Paget cells and the underlying carcinoma supports the theory that these cells are the result of an intraepidermal spread of ductal carcinoma.

Regulation of the cycling of timeless (tim) RNA

Circadian rhythms in Drosophila depend upon expression of the timeless (tim) and period (per) genes, which encode interacting components of the endogenous clock. These two clock genes show a robust circadian oscillation in transcription rate as well as RNA and protein levels. Transcriptional activation of both genes requires the basic helix-loop-helix (bHLH) PAS transcription factors dCLOCK (dCLK) and CYCLE (CYC), which bind E-box elements. We investigated the role of E-box elements in regulating behavioral rhythmicity and tim gene expression. We show that mutation of the upstream E-box in the tim gene prevents the rescue by tim cDNA sequences of the arrhythmic tim(01) phenotype. RNA encoded by this mutated tim transgene fails to cycle and is expressed at low levels. While a tim transgene carrying a wild-type E-box restores behavioral rhythms, tim RNA levels are intermediate to those of the mutant E-box transgenic lines and wild type, and do not display high amplitude cycling. On the other hand, high-amplitude RNA cycling was consistently obtained with a tim transgene that contains genomic, rather than cDNA, sequences. To identify additional sequences that may be required for tim cycling, we investigated the role of an E-box in the first intron of the tim gene through cell culture experiments. In these experiments, the presence of this intron did not have any effect on the activation of tim transcription by dCLK/CYC. As the upstream E-box was implicated in activation by dCLK/CYC in cell culture, we assayed sequences containing this E-box for association with proteins in fly head extracts. These studies provide the first biochemical evidence for an in vivo complex containing dCLK and CYC that binds the tim upstream sequence and is detected at all times of day. Together, these data highlight molecular mechanisms that are critical for behavioral rhythms.

[Studies on the isolation, culture and DNA identification of mycelia of Tricholoma matsutake]

The tissue isolation for Tricholom matsutake(S Ito et Imai) Sing were made with 8 media in 810 test tubes from different positions of 9 basidiocarps of different source and from mycorrhizae, and soil with the fungi in the studies. The results showed that 94 test tubes of slow-growing mycelia were isolated from lamellae and their success percentages of isolation with media PDAS, PDAW, BM, PDA were 74.4%, 355%, 15.6% and 8.9% respectively. The fast-growing mycelia were easily got from the mycorrhizae and soil related to matsutake. The isolates with different culture characteristics were appraised through DNA fingerprinting comparison with matsutake basidiocarps collected from Jilin province, China and reference isolates presented by matsutake research workers of China and Japan, in which RAPD (Random Amplified Polymorphic DNA)-PCR patterns were sharply prepared using 17 arbitrary decamer nucleotide primers screened. The statistical data indicated that all slow-growing mycelia isolated from lamellae had the same DNA fingerprinting patterns as their origin basidiocarps tissues such as pileus (containing lamellae) and stipe, whose similarity coeffecients all were 1.000, and were therefore identified as true Tricholoma matsutake. However, the fast-growing mycelia or yeast colony were identified as not matsutake. The results suggested that matsutake and its own mycelia have DNA homogeneity, and there exists no any other microbe in the basidiocarps. The results also demonstrated that all matsutake from east China and reference isolates of matsutake from southwest China and Japan were one same species Tricholoma matsutake, whose DNA similarity coeffecients varied from 0.934 to 0.994.

Emerging roles for telomerase in regulating cell differentiation and survival: a neuroscientist's perspective

Telomerase is a reverse transcriptase that adds repeats of a DNA sequence (TTAGGG) to the ends of chromosomes (telomeres) in mitotic cells, thus maintaining their length and preventing cell cycle arrest and cell death (cellular senescence). During development of the nervous system, telomerase activity levels are high in neural progenitor cells, but then they decrease as cells differentiate or die. The catalytic subunit of telomerase (TERT) remains at relatively high levels during the process of neuronal differentiation and then decreases sharply during the period when synapses form and programmed cell death occurs. TERT promotes survival of developing brain neurons. Suppression of telomerase activity and TERT expression promotes apoptosis of neurons, whereas overexpression of TERT prevents apoptosis by suppressing cell death at a premitochondrial step in the death cascade TERT may suppress DNA damage and/or apoptotic signals activated by damaged DNA. Recent studies of the transcriptional regulation of the TERT gene suggest that this enzyme may mediate the cell survival-promoting actions of diverse signals including estrogen, cytokines and neurotrophic factors. The elucidation of the functions of telomerase activity and TERT in neuronal differentiation and survival may lead to novel approaches for preventing neuronal death and promoting recovery of function in various neurodegenerative conditions.

Caspase-mediated suppression of glutamate (AMPA) receptor channel activity in hippocampal neurons in response to DNA damage promotes apoptosis and prevents necrosis: implications for neurological side effects of cancer therapy and neurodegenerative disorders

DNA damage in neurons is implicated in the pathogenesis of several neurodegenerative disorders and may also contribute to the often severe neurological complications in cancer patients treated with chemotherapeutic agents. DNA damage can trigger apoptosis, a form of controlled cell death that involves activation of cysteine proteases called caspases. The excitatory neurotransmitter glutamate plays central roles in the activation of neurons and in processes such as learning and memory, but overactivation of ionotropic glutamate receptors can induce either apoptosis or necrosis. Glutamate receptors of the AMPA (alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate) type mediate such physiological and pathological processes in most neurons. We now report that DNA damage can alter glutamate receptor channel activity by a mechanism involving activation of caspases. Whole-cell patch clamp analyses revealed a marked decrease in AMPA-induced currents after exposure of neurons to camptothecin, a topoisomerase inhibitor that induces DNA damage; N-methyl-d-aspartate (NMDA)-induced currents were unaffected by camptothecin. The decrease in AMPA-induced current was accompanied by a decreased calcium response to AMPA. Pharmacological inhibition of caspases abolished the effects of camptothecin on AMPA-induced current and calcium responses, and promoted excitotoxic necrosis. Combined treatment with glutamate receptor antagonists and a caspase inhibitor prevented camptothecin-induced neuronal death. Caspase-mediated suppression of AMPA currents may allow neurons with damaged DNA to withdraw their participation in excitatory circuits and undergo apoptosis, thereby avoiding widespread necrosis. These findings have important implications for treatment of patients with cancer and neurodegenerative disorders.

Chaoslike behavior in nonchaotic systems at finite computation precision

The dynamical behavior of a two-dimensional map is investigated numerically. A chaoslike behavior, i.e., a nonsmooth distribution of the attractor and seemly sensitive dependence of the motion on initial condition is found as the system state is nonchaotic (both Lyapunov exponents are nonpositive). The key point for this strange behavior is that the mode corresponding to the second negative Lyapunov exponent contains positive local Lyapunov exponent segments. It is argued that this kind of behavior may be typical and easily observed in practical numerical computations and experiments where small noise is inevitable.

[Effect of estrogen on hemodynamics and vascular remodeling with Takayasu arteritis]

This study utilized Takayasu arteritis (TA) model to do the experiment in order to observe the remodeling of arterial geometry. Plasma estrogen, progesterone and products of nitrous oxide (NO2- and NO3-) were examined. Qualitative analyses of maximum (MAX), minimum (MIN) and mean (MEAN) velocity of blood flow, resistant index (PI), pulsatile index (PI), and shear stress (SS) of abdominal aorta were performed. The results showed that plasma estrogen, progesterone and products of nitrous oxide were respectively 1137.80 +/- 189.30 pg.ml-1, 14.10 +/- 1.61 micrograms.ml-1 and 195.78 +/- 53.01 mumol.L-1 in experiment group, whereas in control group, they were 34.74 +/- 10.20 pg.ml-1, 2.60 +/- 1.83 micrograms.ml-1 and 12.16 +/- 3.28 mumol.L-1 respectively, P < 0.01. In comparison of hemodynamic parameters of abdominal aorta, the MAX and MIN of experiment group were profoundly higher than those of control group. SS increased markedly in experiment group. The observation of arterial remodeling in vitro found wall thickening. The thickness of abdominal aortic wall and inside diameter of vessel cavity ratio (h/Di) was 0.6145 +/- 0.1654 in experiment group and 0.2151 +/- 0.0266 in control group, P < 0.01. The arterial collagen content in experimental group was significantly higher than that in control group. Hyperestrinemia gives rise to a series of hemodynamic alterations, influences vessel remodeling along with TA, and finally results in arterial stenosis, occlusion or aneurysms due to the constitutional composition of vascular wall reforming.

[Arousals from sleep in patients with obstructive disordered breathing: a comparison study for mechanisms]

OBJECTIVE

To explore the stimuli triggering respiratory arousal.

METHODS

Twenty-five patients with excessive daytime sleepiness (EDS) were monitored by nocturnal polysomonography (PSG) and respiratory inductive plethysmography. Patients with obstructive apnea/hypopnea index (AHI) >/= 5/h were diagnosed as obstructive sleep apnea syndrome (OSAS). Patients with Epworth Sleepiness Score >/= 12, frequent inspiratory flow limitation related arousal during sleep and AHI < 5/h were diagnosed as upper airway resistance syndrome (UARS). Seven normal subjects were recruited as controls.

RESULTS

Patients with OSAS: AHI (32.8 +/- 19.1)/h, percentage of time spend when oxygen saturation lower than 90% (SLT90%) (11.3 +/- 16.5)%, arousal index (ArI) (35 +/- 17)/h, n = 15. Patients with UARS: AHI (2.5 +/- 1.4)/h, SLT90% (0.1 +/- 0.1)%, ArI (30 +/- 16)/h, n = 10. Normal subjects: AHI (5.9 +/- 4.4)/h, SLT90% (0.2 +/- 0.4)%, ArI (13 +/- 5)/h, n = 7. Though the levels of AHI and SLT90% in patients with UARS were similar to those in normal subjects (H = 2.92, P = 0.87 or H = 0.086, P = 0.77), much lower than those in OSAS patients (H = 12.3, P = 0.000 5 and H = 6.64, P = 0.01), ArI in UARS was just as high as that in OSAS (H = 0.49, P = 0.48).

CONCLUSION

Arousals from sleep in patients with obstructive sleep disordered breathing might be mainly caused by inspiratory flow limitation rather than by episodic apnea or desaturation.

Discovery of new DNA amplification loci in prostate cancer by comparative genomic hybridization

BACKGROUND

DNA sequence amplifications are involved in the progression of many tumor types, and have also been found in advanced prostate cancer. The aim of this study was to detect new loci of DNA amplifications in prostate cancer.

METHODS

Comparative genomic hybridization (CGH) was used for whole genome screening of DNA sequence copy number alterations in 27 advanced prostate cancers.

RESULTS

The most prevalent changes were losses of 8p, 13q (52%, each), 6q (48%), 18q (37%), 5q (30%), 2q, 4q and 16q (26%, each), and gains of 8q (48%), Xq (40%), and Xp (26%). In addition, 16 high-level amplifications were found. These included Xq12 (five), 8q24 (two), and 11q13 (one) with known putative target genes (androgen receptor, MYC and Cyclin D1), and 1q21-25 (three), 10q22 (two), 17q23-24 (two), and 8q21 (one) where the target genes remain unknown.

CONCLUSIONS

High-level amplifications at different chromosomal sites occur in advanced prostate cancer. The detection of amplified chromosomal regions may serve as a starting point to discover novel oncogenes involved in prostate cancer progression.

CDKNA2A mutation analysis, protein expression, and deletion mapping of chromosome 9p in conventional clear-cell renal carcinomas: evidence for a second tumor suppressor gene proximal to CDKN2A

Inactivation of tumor suppressor genes on chromosome 9p is considered a critical event in renal cell carcinoma pathogenesis. Alterations of CDKN2A on 9p21 have been reported in renal cancer cell lines, but their relevance for primary renal carcinomas is unclear. Loss of heterozygosity (LOH) was analyzed by using four polymorphic microsatellites at D9S970 (9p12-9p13), D9S171 (9p13), D9S1748 (9p21), and D9S156 (9p21) in 113 primary conventional clear-cell renal cell carcinomas (CRCCs). Allelic deletion was detected in 21 of 88 informative CRCCs (24%) with the highest rate of LOH being observed at D9S171 on 9p13 (20%). Chromosome 9p LOH was associated with short tumor-specific survival in stage pT3 RCC (P = 0.01). Fluorescence in situ hybridization analysis of 54 CRCCs revealed no homozygous CDKN2A deletions indicating that this mechanism of CDKN2A inactivation is rare in CRCC. Sequencing of 113 CRCCs showed that 13 tumors (12%) had a 24-bp deletion abrogating codons 4 through 11 of CDKN2A. Immunohistochemical CDKN2A expression was absent in normal renal tissue and was only detected in six of 382 CRCCs (1.5%) on a renal tumor microarray. These data suggest that CDKN2A alterations are present in a small subset of CRCCs and a second, yet unknown tumor suppressor gene proximal to the CDKN2A locus, may play a role in CRCC development.

[Resection of pelvic retroperitoneal neoplasm and reconstruction of iliac blood vessels: report of 22 cases]

OBJECTIVE

To study the surgical manipulation of iliac blood vessels invaded by pelvic tumors in order to raise the resection rate.

METHODS

We reviewed 22 cases of resection for pelvic retroperitoneal tumors along with the reconstruction of iliac blood vessels in our hospital from July 1994 to January 2000. In 22 cases, 8 received operation on the right iliac arteries and veins, and 14 on the left.

RESULTS

Follow-up for 4 months to 5 years and 10 months (average 3.6 years) showed that 3 patients had recurrence and needed secondary operation. All the grafts were patent except one vein graft occlusion 7 months after operation.

CONCLUSION

Resection of pelvic retroperitoneal neoplasm combined with reconstruction of iliac blood vessels is safe, effective and practical to raise the excision rate and decrease the recurrence rate.

Genetic changes in clinically organ-confined prostate cancer by comparative genomic hybridization

OBJECTIVES

The genetic basis underlying prostate cancer development and progression is poorly understood. The primary aim of this study was to identify chromosomal regions important for progression in clinically localized prostate cancer removed by radical prostatectomy.

METHODS

Comparative genomic hybridization was used for whole genome screening of DNA sequence copy number alterations in 28 pathologically organ-confined tumors (pT2) and 28 tumors with infiltration of the seminal vesicles (pT3b).

RESULTS

Comparative genomic hybridization analysis showed on average 2.0 +/- 2.4 chromosomal alterations per tumor with more frequent losses (mean 1.3 +/- 1.8) than gains (mean 0.7 +/- 1.0). The percentage of tumors without alterations was higher in Stage pT2 (21%) than in Stage pT3b (50%). Losses of 8p (21%), 13q (21%), 5q (14%), 16q (14%), and 18q (13%) and gains of Xq (21%) and 8q (9%) were the most prevalent changes. Distinct regional alterations included minimal overlapping regions of loss at 5q13-q21, 6q14-q21, and 18q21-qter. There was only a small increase in the number of alterations from Stage pT2 to Stage pT3b (mean 1.6 +/- 2.3 versus 2.5 +/- 2.4). However, two individual alterations-gain of 8q and loss of 18q-were significantly more frequent in Stage pT3b than in Stage pT2 prostate cancer (P = 0.02 and P = 0.04, respectively), suggesting that genes in these regions may be important for prostate cancer progression.

CONCLUSIONS

The detection of chromosome 8q gains and 18q losses and the identification of the corresponding target genes could become a molecular tool for better characterization of clinically localized prostate cancer.

Combinatorial signaling in the specification of unique cell fates

How multifunctional signals combine to specify unique cell fates during pattern formation is not well understood. Here, we demonstrate that together with the transcription factor Lozenge, the nuclear effectors of the EGFR and Notch signaling pathways directly regulate D-Pax2 transcription in cone cells of the Drosophila eye disc. Moreover, the specificity of D-Pax2 expression can be altered upon genetic manipulation of these inputs. Thus, a relatively small number of temporally and spatially controlled signals received by a set of pluripotent cells can create the unique combinations of activated transcription factors required to regulate target genes and ultimately specify distinct cell fates within this group. We expect that similar mechanisms may specify pattern formation in vertebrate developmental systems that involve intercellular communication.

[A report of two Chinese familial Budd-Chiari syndrome]

OBJECTIVE

To investigate the etiology of two Chinese familial Budd-Chiari syndrome (BCS).

METHOD

Four patients with familial BCS (from A and B families), and the other 41 family members were detected by angiography, ultrasound Dopler, etiology analysis and Factor V Leiden (FvL) mutation analysis.

RESULT

Four BCS patients were proved by angiography, 2 by ultra sound Dopler in family A. Ten members in family A were varicosis in low extremeties. FvL mutation was detected in 4 of 6 patients and 2 normal family members. A II(2), A III(7, 11, 15,) B II(10) and B III(5) had FvL mutation. The FvL mutations were compatible with Mendel hereditary law.

CONCLUSION

FvL mutation may be one of main risk factors and varicosis in low extremeties may be another risk factors for familial BCS.

[Detection of epidermal growth factor receptor gene amplification in human laryngeal carcinomas by means of fluorescence in situ hybridization]

OBJECTIVE

To detect epidermal growth factor receptor(EGFR) gene amplification in human laryngeal carcinoma Hep-2 cell line and laryngeal carcinoma tissues.

METHODS

The technique of fluorescence in situ hybridization(FISH).

RESULTS

The EGFR gene amplification of a laryngeal carcinoma Hep-2 cell line and 5 laryngeal carcinoma tissues were detected by FISH. In the metaphase chromosome and interphase nuclei of Hep-2 cell line and 2 laryngeal carcinoma tissues, distinct cluster and multiple dot signals were found. In the interphase nuclei of the other 3 laryngeal carcinoma tissues, no increase in the number or extent of the hybrid signals was found.

CONCLUSION

Compared with normal diploid cell, the EGFR gene amplification was observed at different levels ranging from 2 to 8 folds in metaphase chromosome and interphase nuclei of Hep-2 cell line and 2 laryngeal carcinoma tissues while no amplification was observed in the other 3 laryngeal carcinoma tissues. The results demonstrate that quantitative detection of amplified gene by FISH in the metaphase chromosome and interphase nuclei is useful for detection of laryngeal carcinoma tissues.

Rapacuronium recovery characteristics and infusion requirements during inhalation versus propofol-based anaesthesia

We examined the effect of four maintenance anaesthetics on the neuromuscular blocking activity and spontaneous recovery characteristics after a short-term infusion of rapacuronium. Eighty ASA I-III adult patients undergoing elective surgery were studied at four centres. Anaesthesia was induced with propofol 1.5-2.5 mg kg-1 and fentanyl 1-2 micrograms kg-1, followed by a bolus of rapacuronium 1.5 mg kg-1. The patients were randomized to receive either desflurane (2-4% end-tidal, ET), sevoflurane (0.75-1.5% ET), isoflurane (0.4-0.8% ET), or a propofol infusion (75-150 micrograms kg-1 min-1) for maintenance of anaesthesia in combination with nitrous oxide (60-70%) in oxygen. When the first twitch (T1) of a train-of-four stimulus (using the TOF Guard accelerometer) returned to 5%, an infusion of rapacuronium was started at 3 mg kg-1 h-1 and adjusted to maintain T1/T0 at 10%. The duration of infusion lasted between 45 and 60 min, and the average infusion rates of rapacuronium were similar in all groups, ranging from 1.6 to 2.5 mg kg-1 h-1. There were no significant differences among the groups in the times for T1/T0 to return to 25%, 75% or 90%, or for T4/T1 to return to 70% and 80% upon discontinuation of the infusion. When potent inhalation anaesthetics are used in clinically relevant concentrations for maintenance of anaesthesia, the neuromuscular recovery profile of rapacuronium administered as a variable-rate infusion for up to 1 h is similar to that found with a propofol-based anaesthetic technique.

The catalytic subunit of telomerase protects neurons against amyloid beta-peptide-induced apoptosis

The catalytic subunit of telomerase (TERT) is a specialized reverse transcriptase that has been associated with cell immortalization and cancer. It was reported recently that TERT is expressed in neurons throughout the brain in embryonic and early postnatal development, but is absent from neurons in the adult brain. We now report that suppression of TERT levels and function in embryonic mouse hippocampal neurons in culture using antisense technology and the telomerase inhibitor 3' -azido-2' 3' -dideoxythymidine significantly increases their vulnerability to cell death induced by amyloid beta-peptide, a neurotoxic protein believed to promote neuronal degeneration in Alzheimer's disease. Neurons in which TERT levels were reduced exhibited increased levels of oxidative stress and mitochondrial dysfunction following exposure to amyloid beta-peptide. Overexpression of TERT in pheochromocytoma cells resulted in decreased vulnerability to amyloid beta-peptide-induced apoptosis. Our findings demonstrate a neuroprotective function of TERT in an experimental model relevant to Alzheimer's disease, and suggest the possibility that restoration of TERT expression in neurons in the adult brain may protect against age-related neurodegeneration.

Interrelations between plasma homocysteine and intracellular S-adenosylhomocysteine

S-Adenosylhomocysteine, a potent intracellular methylation inhibitor, is suggested as a potential mediator for hyperhomocysteinemia-related vascular changes. We investigated the effect of acute and chronic hyperhomocysteinemia on intracellular S-adenosylhomocysteine and S-adenosylmethionine in rats and humans. Elevated plasma homocysteine in rats infused with homocysteine produced an increase in S-adenosylhomocysteine (P < 0.001) but not S-adenosylmethionine levels (P > 0.05) in various rat tissues. However intraerythrocyte S-adenosylhomocysteine and S-adenosylmethionine levels were not changed in homocysteine-infused rats and human subjects with experimentally acute hyperhomocysteinemia by methionine loading test. In contrast, erythrocyte S-adenosylhomocysteine levels were significantly higher in chronic renal failure patients, who had chronically elevated plasma homocysteine levels, than in either vascular disease patients or healthy controls (P < 0.05). In conclusion, acute hyperhomocysteinemia can increase intracellular S-adenosylhomocysteine levels in tissues actively involved in homocysteine metabolism. The findings are relevant to homocysteine-related endothelial dysfunction since S-adenosylhomocysteine modulates endothelial cell apoptosis.

[Microsurgical treatment of medially located tumors of the middle skull base]

OBJECTIVE

To report the results of microsurgical treatment of tumors medially located in the middle skull base.

METHODS

The preoperative MRI features, operative approaches, results of operation and postoperative complications in 26 cases were reviewed.

RESULTS

Total resection of the tumors was achieved in 12 cases, subtotal resection in 9 cases, partial resection in 6 cases. Two patients died of operation. Cranial nerve palsy remained unchanged in 5 cases and became exacerbated in 5 cases. Clinical improvement was observed in 15 cases.

CONCLUSION

The combined frontotemporal-zygomatic approach to remove medially located tumors of the middle skull base is adequate.

The catalytic subunit of telomerase is expressed in developing brain neurons and serves a cell survival-promoting function

Telomerase, a specialized reverse transcriptase (RT) linked to cell immortalization and cancer, has been thought not to be expressed in postmitotic cells. We now report that telomerase activity and its essential catalytic subunit, telomerase reverse transcriptase (TERT), are expressed in neurons in the brains of rodents during embryonic and early postnatal development, and are subsequently downregulated. Suppression of TERT expression in cultured embryonic hippocampal neurons increases their vulnerability to apoptosis and excitotoxicity. Overexpression of TERT in PC12 cells suppresses apoptosis induced by trophic factor withdrawal. TERT exerts its anti-apoptotic action at an early stage of the cell death process prior to mitochondrial dysfunction and caspase activation. TERT may serve a neuron survival-promoting function in the developing brain, and downregulation of TERT in the adult brain may contribute to increased neuronal vulnerability in various age-related neurodegenerative disorders.

[Assessment of extracranial internal carotid artery stenosis by duplex scanning magnetic resonance angiography and digital subtraction angiography: a comparative study]

OBJECTIVE

To investigate the correlation between duplex scanning, magnetic resonance angiography (MRA), and digital subtraction angiography (DSA) in the evaluation of extracranial internal carotid artery (EICA) stenosis.

METHODS

All the examinations mentioned-above were performed on 32 patients. According to NASCET, EICA stenosis were classified into four grades: mild (the diameter reduction < 30%), moderate (31% approximately 69%), severe (70% approximately 99%), and total occlusion.

RESULTS

One (3.1%) patient suffered from acute brain infarction after DSA. To compare duplex with DSA, Kappa = 0.78, and by the use of a severe or a greater than 30% stenosis as a positive study, the sensitivity, specificity and accuracy were 78%, 95%, 92% and 97%, 91%, 94%, respectively. To compare MRA with DSA, Kappa = 0.73, and with the same criteria, the sensitivity, specificity and accuracy were 78%, 90%, 89% and 97%, 91%, 94%, respectively. In the evaluation where the results of duplex and MRA were in agreement, to compare duplex + MRA with DSA, Kappa = 0.93, and the sensitivity, specificity and accuracy in the diagnosis of severe stenosis were 100%, 95% and 96%, and the accuracy in the diagnosis of > 30% stenosis was 100%.

CONCLUSIONS

There is good correlativity between duplex scanning, MRA and DSA in the examination of EICA stenosis. A combination of duplex and MRA with their results in agreement may ultimately eliminate the need of DSA in the evaluation of EICA stenosis.

[FHIT gene is abnormal in laryngeal carcinoma]

OBJECTIVE

To determine the role of FHIT gene in laryngeal carcinogenesis.

METHODS

Laryngeal cancer cell line Hep-2, HeLa cell line and 80 primary tumors from patients with laryngeal cancer were studied by means of RT-PCR, sequencing and microsatellite analysis.

RESULTS

Abnormal transcripts of FHIT gene were found in the two cell lines and 70% (14/20) of primary laryngeal carcinomas. Aberrant laryngeal tumor transcripts often lack more than two exons of FHIT gene. Microsatellite analysis showed that both loss of heterozygosity and microsatellite instability of FHIT gene existed in laryngeal carcinoma and the former was more common.

CONCLUSION

FHIT gene participates in the laryngeal carcinogenesis and may be one of the candidate tumor suppressor genes.

Characterization of the block in replication of nucleocapsid protein zinc finger mutants from moloney murine leukemia virus

Mutagenesis studies have shown that retroviral nucleocapsid (NC) protein Zn(2+) fingers (-Cys-X(2)-Cys-X(4)-His-X(4)-Cys- [CCHC]) perform multiple functions in the virus life cycle. Moloney murine leukemia virus mutants His 34-->Cys (CCCC) and Cys 39-->His (CCHH) were able to package their genomes normally but were replication defective. Thermal dissociation experiments showed that the CCHH mutant was not defective in genomic RNA dimer structure. Primer tRNA placement on the viral genome and the ability of the tRNA to function in reverse transcription initiation in vitro also appear normal. Some "full-length" DNA copies of the viral genome were synthesized in mutant virus-infected cells. The CCCC and CCHH mutants produced these DNA copies at greatly reduced levels. Circle junction fragments, amplified from two-long-terminal-repeat viral DNA (vDNA) by PCR, were cloned and characterized. Remarkably, it was discovered that vDNA isolated from cells infected with mutant virions had a wide variety of abnormalities at the site at which the two ends of the linear precursor had been ligated to form the circle (i.e., the junction between the 5' end of U3 and the 3' end of U5). In some molecules, bases were missing from regions corresponding to the U3 and U5 linear vDNA termini; in others, the viral sequences extended either beyond the U5 sequences into the primer-binding site and 5' leader or beyond the U3 sequences into the polypurine tract into the env coding region. Still other molecules contained nonviral sequences between the linear vDNA termini. Such defective genomes would certainly be unsuitable substrates for integration. Thus, strict conservation of the CCHC structure in NC is required for infection events prior to and possibly including integration.

[Antibiotic resistance and plasmid profiles of Vibrio isolates from cultured Sparus sarba]

A total of 51 potential pathogenic vibrios were isolated from moribund silver seabream Sparus sarba, which were collected from local fish farms of Hong Kong. All the isolates were classified and identified as 7 species by the API 20 E system and the scheme of Alsina & Blanch. These species were Vibrio alginolyticus (24 strains), Vibrio vulnificus (12 strains), Vibrio parahaemolyticus(7 strains), Vibrio logei(4 strains), Vibrio pelagius II(2 strains), Vibrio fluvialis (1 strains) and Vibrio meditterranei (1 strains). Among these isolates, the three predominant species (V. alginolyticus, V. vulnificus and V. parahaemolyticus) were confirmed to be virulent to sea bream by experimental challenge. All isolates were also screened for plasmid DNA by agarose gel electrophoresis and tested for susceptibility to 16 antimicrobial agents by the agar dilution method. Of the 51 isolates examined, all strains were sensitive to ceftriaxone, streptomycin, nalidixic acid and rifampicin, and almost all were sensitive to ceftazidime, netilimicin, chloramphenicol and sulfamethoxazole except one or two strains. Most isolates were resistant to ampicillin (60. 8%), cefuroxime (66.7%), amikacin(55%), kanamycin(58.8%) and trimethoprinm (76.5%). Fifteen of the 51 isolates harboured 1-4 plasmids, with sizes ranging from 9 to 123 kb. Both the plasmids and the associated antimicrobial resistance (ampicillin, cefuroxime and trimethoprim) of 9 isolates could be transferred to recipient by single-step conjugation, however, the frequencies were very low, ranging from 10(-11) to 10(-9). The present results indicate that resistance to these antibiotics is chromosomal.

[The detection and clinical significance of telomerase activity in supraglottic carcinomas]

OBJECTIVE

To study the expression and significance of telomerase activity in laryngeal carcinoma.

METHOD

We detected telomerase activity of HEP-2 cell line, 26 cases of supraglottic carcinoma tissues and 15 cases of peri-carcinoma tissues with PCR-based assay designated TRAP (for telomeric repeat amplification protocol).

RESULT

The telomerase positive rate of supraglottic carcinoma 84.6% (22/26) was obvious higher than that of peri-carcinoma 40% (6/15), P < 0.01. No significant differences in positive rates were found among different groups divided according to clinical stage or metastasis of cervical lymph node, P > 0.05.

CONCLUSION

Telomerase activation is related to immortalization process, though not much helpful in diagnosis of supraglottic carcinoma.

[FHIT gene is abnormal in Chinese lung cancers]

OBJECTIVE

To determine whether the FHIT gene at 3p14.2 is abnormal in Chinese lung cancers.

METHODS

Matched normal and cancerous tissues from 21 cases of primary pulmonary squamous cell carcinoma (SQC) and 10 cases of adenocarcinoma (ADC) were obtained immediately after surgery. Total RNA was extracted and the FHIT gene was detected by RT-PCR and DNA sequencing technology.

RESULTS

Normal-sized FHIT transcript was detected in all 31 cases of normal matched tissues. Aberrant transcripts were observed in 15 (48%) of 31 cases of cancerous tissues, 57% (12/21) in SQC and 33% (3/10) in ADC, respectively. All the abnormal transcripts observed lacked exon 5, the first coding exon. The sequence analyses of the aberrant cDNAs revealed deletions of various regions between exon 4 and 10. A synonymous mutation in E8, codon98CAT(H)-->CAC(H), was found in a SQC.

CONCLUSION

The high deletion rate of the FHIT gene in Chinese lung cancer supports the hypothesis that the FHIT gene alteration is involved in tumorigenic development of human neoplasm.

[Shi Ji Yao Yu, the earliest extant monograph on TCM nursery]

Nursery of traditional Chinese medicine (NTCM) has a long history. However, due to the change and influence of the era, society, life style, and many other factors, NTCM did not become an independent discipline for a long period. Although there have been many articles about NTCM appearing in various historical books of traditional Chinese medicine, books specializing on NTCM were not available until later. The earliest ancient book, which is still currently available, describing NTCM in details is the "Shi Ji Yao Yu" written by Qian Xiang in the Qing Dynasty. The book explains the key issues of taking care of a patient's emotional well-being, life style, diet, illness, and drug administration which are of great practical significance now and for the future.

Superoxide mediates the cell-death-enhancing action of presenilin-1 mutations

The mechanism whereby mutations in the presenilin-1 (PS-1) gene on chromosome 14 cause early-onset inherited Alzheimer's disease are unknown. We report that PC6 neural cells (a subclone of PC12 cells) expressing PS-1 mutations (M146V and L286V) exhibit increased superoxide production, nitrotyrosine accumulation, and membrane lipid peroxidation following exposure to amyloid beta-peptide 1-42 (Abeta). Mitochondrial calcium accumulation and membrane depolarization following exposure to Abeta were enhanced in cells expressing mutant PS-1. Overexpression of mitochondrial Mn-SOD greatly reduced superoxide production, nitrotyrosine formation, membrane lipid peroxidation, intramitochondrial calcium accumulation, and membrane depolarization following exposure to Abeta and conferred resistance to the apoptosis-enhancing action of the PS-1 mutations. Nitric oxide synthase inhibitors and the peroxynitrite scavenger uric acid blocked the apoptosis-enhancing action of PS-1 mutations. The data suggest pivotal roles for superoxide production and resulting peroxynitrite formation in the pathogenic mechanism of PS-1 mutations.

Spread of drug-resistant Streptococcus pneumoniae in Asian countries: Asian Network for Surveillance of Resistant Pathogens (ANSORP) Study

Antimicrobial susceptibility of 996 isolates of Streptococcus pneumoniae from clinical specimens was investigated in 11 Asian countries from September 1996 to June 1997. Korea had the greatest frequency of nonsusceptible strains to penicillin with 79.7%, followed by Japan (65.3%), Vietnam (60.8%), Thailand (57.9%), Sri Lanka (41.2%), Taiwan (38.7%), Singapore (23.1%), Indonesia (21.0%), China (9.8%), Malaysia (9.0%), and India (3.8%). Serotypes 23F and 19F were the most common. Pulsed-field gel electrophoresis (PFGE) of 154 isolates from Asian countries showed several major PFGE patterns. The serotype 23F Spanish clone shared the same PFGE pattern with strains from Korea, Japan, Singapore, Taiwan, Thailand, and Malaysia. Fingerprinting analysis of pbp1a, pbp2x, and pbp2b genes of 12 strains from six countries also showed identical fingerprints of penicillin-binding protein genes in most strains. These data suggest the possible introduction and spread of international epidemic clones into Asian countries and the increasing problems of pneumococcal drug resistance in Asian countries for the first time.

An essential role for the Drosophila Pax2 homolog in the differentiation of adult sensory organs

The adult peripheral nervous system of Drosophila includes a complex array of mechanosensory organs (bristles) that cover much of the body surface of the fly. The four cells (shaft, socket, sheath, and neuron) which compose each of these organs adopt distinct fates as a result of cell-cell signaling via the Notch (N) pathway. However, the specific mechanisms by which these cells execute their conferred fates are not well understood. Here we show that D-Pax2, the Drosophila homolog of the vertebrate Pax2 gene, has an essential role in the differentiation of the shaft cell. In flies bearing strong loss-of-function mutations in the shaven function of D-Pax2, shaft structures specifically fail to develop. Consistent with this, we find that D-Pax2 protein is expressed in all cells of the bristle lineage during the mitotic (cell fate specification) phase of bristle development, but becomes sharply restricted to the shaft and sheath cells in the post-mitotic (differentiative) phase. Two lines of evidence described here indicate that D-Pax2 expression and function is at least in part downstream of cell fate specification mechanisms such as N signaling. First, we find that the lack of late D-Pax2 expression in the socket cell (the sister of the shaft cell) is controlled by N pathway activity; second, we find that loss of D-Pax2 function is epistatic to the socket-to-shaft cell fate transformation caused by reduced N signaling. Finally, we show that misexpression of D-Pax2 is sufficient to induce the production of ectopic shaft structures. From these results, we propose that D-Pax2 is a high-level transcriptional regulator of the shaft cell differentiation program, and acts downstream of the N signaling pathway as a specific link between cell fate determination and cell differentiation in the bristle lineage.

Joint action of two RNA degradation pathways controls the timing of maternal transcript elimination at the midblastula transition in Drosophila melanogaster

Maternally synthesized RNAs program early embryonic development in many animals. These RNAs are degraded rapidly by the midblastula transition (MBT), allowing genetic control of development to pass to zygotically synthesized transcripts. Here we show that in the early embryo of Drosophila melanogaster, there are two independent RNA degradation pathways, either of which is sufficient for transcript elimination. However, only the concerted action of both pathways leads to elimination of transcripts with the correct timing, at the MBT. The first pathway is maternally encoded, is targeted to specific classes of mRNAs through cis-acting elements in the 3'-untranslated region and is conserved in Xenopus laevis. The second pathway is activated 2 h after fertilization and functions together with the maternal pathway to ensure that transcripts are degraded by the MBT.

Use of the cuffed oropharyngeal airway as an alternative to the laryngeal mask airway with positive-pressure ventilation

BACKGROUND

The cuffed oropharyngeal airway is a modified Guedel-type oral airway with a cuff at its distal end. The objectives of this study were to compare the ability of the cuffed oropharyngeal airway and the laryngeal mask airway to provide positive-pressure ventilation during general anesthesia, and to assess their relative ease of use and ability to reduce total fresh gas flow rates.

METHODS

In this prospective, randomized study, a cuffed oropharyngeal airway (n = 25) or a laryngeal mask airway (n = 25) device was inserted after induction of anesthesia intravenously using 2 mg/kg propofol. While anesthesia was maintained with sevoflurane and nitrous oxide, the leak pressure, leak fraction (the fractional difference between the inspired and expired tidal volume), minimum fresh gas flow rate, and need for airway manipulations were determined. The anesthesia provider who inserted the device completed an evaluation form at the end of the 15-min study period.

RESULTS

Positive-pressure ventilation was established successfully on the first attempt in 92% of the patients when the cuffed oropharyngeal airway was used and in 88% of the patients when the laryngeal mask airway device was used. However, manipulations of the airway device were necessary more frequently (8 vs. 1 patient; P < 0.05) and the leak pressure was less (22 +/- 6 cm water vs. 26 +/- 5 cm water; P < 0.05) with the cuffed oropharyngeal airway than with the laryngeal mask airway. In addition, the leak fraction (0.19 +/- 0.18 vs. 0.31 +/- 0.22; P < 0.05) and the minimum fresh gas flow rate (1.3 +/- 1.5 vs. 2.4 +/- 2.5; P = 0.12) were less in the laryngeal mask airway group.

CONCLUSIONS

Positive-pressure ventilation is possible with the laryngeal mask airway and cuffed oropharyngeal airway devices. Although the cuffed oropharyngeal airway can be inserted easily by inexperienced users with a high first-attempt success rate (> 90%), manipulations of the device may be required to maintain a patent airway. The laryngeal mask airway device allows positive-pressure ventilation at slightly greater peak inspiratory pressures.

The effect of environmental conditions and glucose feeding in shaking flask on glutathione (GSH) production

The effects of pH, broth volume, initial sugar concentration, ratio of carbon to nitrogen and phosphorus, and the glucose feeding method on GSH production in a shaking flask were investigated. The results showed that the proper pH and broth content for GSH production were 6.0 and 60 ml broth per 500 ml flask, respectively. The initial glucose concentration distinctly affected the GSH production; the intracellular GSH content of yeast would decrease when the initial glucose concentration was beyond 12 g/L. A glucose feeding strategy with the purpose of controlling the specific growth rate at an expected value was developed and applied to a 12 hour fermentation with the total glucose concentration 26.2 g/L; the final cell concentration (DCW) and the intracellular GSH content could reach 8.78 g/L and 13.6 mg/g, respectively, while the total GSH in the broth was 119.4 mg/L and the yield of cell to glucose was 0.335 g/g.

Degradation of pinene by Bacillus pallidus BR425

An aerobic thermophile has been isolated from an alpha-pinene enrichment culture. The isolate, which was designated BR425, has been tentatively identified as Bacillus pallidus using 16S ribosomal RNA gene sequencing and organism morphology. Monophasic and biphasic incubations of BR425 cells with alpha-pinene, beta-pinene, and limonene yielded a number of oxidized monoterpene metabolites with carveol as a common metabolite. A pinene degradation pathway with carveol and carvone as central metabolic intermediates is suggested.

[Loss of heterozygosity and microsatellite instability in laryngeal carcinoma near p16 gene]

OBJECTIVE

To search for the minimal overlap region of tumor suppressor gene in laryngeal carcinoma and discuss the correlation of p16 gene with laryngeal carcinogenesis.

METHODS

Five microsatellite polymorphism markers near p16 gene were selected to detect loss of heterozygosity (LOH) and microsatellite instability (MI) in 60 cases of laryngeal squamous cell carcinoma.

RESULTS

The frequencies of LOH in 5 markers were less than 23.1%, while the frequencies of MI in 2 markers were higher, with the highest frequency (46.1%) in D9S1752.

CONCLUSION

The results suggest that the deletion of p16 gene does not play an important role in the laryngeal carcinogenesis and there may exist a gene around D9S1752 participating in the development of laryngeal carcinoma, which correlates with the mutation of repair gene.

Anti-apoptotic role of telomerase in pheochromocytoma cells

Telomerase is a protein-RNA enzyme complex that adds a six-base DNA sequence (TTAGGG) to the ends of chromosomes and thereby prevents their shortening. Reduced telomerase activity is associated with cell differentiation and accelerated cellular senescence, whereas increased telomerase activity is associated with cell transformation and immortalization. Because many types of cancer have been associated with reduced apoptosis, whereas cell differentiation and senescence have been associated with increased apoptosis, we tested the hypothesis that telomerase activity is mechanistically involved in the regulation of apoptosis. Levels of telomerase activity in cultured pheochromocytoma cells decreased prior to cell death in cells undergoing apoptosis. Treatment of cells with the oligodeoxynucleotide TTAGGG or with 3,3'-diethyloxadicarbocyanine, agents that inhibit telomerase activity in a concentration-dependent manner, significantly enhanced mitochondrial dysfunction and apoptosis induced by staurosporine, Fe2+ (an oxidative insult), and amyloid beta-peptide (a cytotoxic peptide linked to neuronal apoptosis in Alzheimer's disease). Overexpression of Bcl-2 and the caspase inhibitor zVAD-fmk protected cells against apoptosis in the presence of telomerase inhibitors, suggesting a site of action of telomerase prior to caspase activation and mitochondrial dysfunction. Telomerase activity decreased in cells during the process of nerve growth factor-induced differentiation, and such differentiated cells exhibited increased sensitivity to apoptosis. Our data establish a role for telomerase in suppressing apoptotic signaling cascades and suggest a mechanism whereby telomerase may suppress cellular senescence and promote tumor formation.