High frequency of chromosome 3p deletion in histologically normal nasopharyngeal epithelia from southern Chinese

We have examined the presence of loss of heterozygosity (LOH) on chromosome 3p in histologically normal nasopharyngeal epithelia (NP), dysplastic lesions, and carcinoma of the nasopharynx from different ethnic and geographic regions. Microdissected normal NP from noncancerous individuals and nasopharyngeal carcinoma (NPC) samples from both the high-risk group (southern Chinese in Hong Kong) and two low-risk groups for NPC (central/northern Chinese in Anhui/Beijing and Caucasians in Toronto) were included. All NPC samples showed high incidence of 3p deletion (81-100%). High frequencies of LOH on 3p were also detected in normal NP (73.9%) and dysplastic lesions (75%) from the southern Chinese. Significant lower frequency of LOH on 3p was noted in normal NP from the low-risk groups (20%) than those from high-risk groups (P = 0.0003). The presence of such genetic alterations in the histologically normal NP and dysplastic lesions suggests that it is an early event in tumor development. The higher frequency of 3p LOH found in normal NP from southern Chinese compared with those from low-risk groups may be related to the distinct cancer incidence among these populations.

Vaccine potential of poly-1-6 beta-D-N-succinylglucosamine, an immunoprotective surface polysaccharide of Staphylococcus aureus and Staphylococcus epidermidis

Staphylococcus aureus and S. epidermidis are among the most common causes of nosocomial infection, and S. aureus is also of major concern to human health due to its occurrence in community-acquired infections. These staphylococcal species are also major pathogens for domesticated animals. We have previously identified poly-N-succinyl beta-1-6 glucosamine (PNSG) as the chemical form of the S. epidermidis capsular polysaccharide/adhesin (PS/A) which mediates adherence of coagulase-negative staphylococci (CoNS) to biomaterials, serves as the capsule for strains of CoNS that express PS/A, and is a target for protective antibodies. We have recently found that PNSG is made by S. aureus as well, where it is an environmentally regulated, in vivo-expressed surface polysaccharide and similarly serves as a target for protective immunity. Only a minority of fresh human clinical isolates of S. aureus elaborate PNSG in vitro but most could be induced to do so under specific in vitro growth conditions. However, by immunofluorescence microscopy, S. aureus cells in infected human sputa and lung elaborated PNSG. The ica genes, previously shown to encode proteins in CoNS that synthesize PNSG, were found by PCR in all S. aureus strains examined, and immunogenic and protective PNSG could be isolated from S. aureus. Active and passive immunization of mice with PNSG protected them against metastatic kidney infections after intravenous inoculation with eight phenotypically PNSG-negative S. aureus. Isolates recovered from kidneys expressed PNSG, but expression was lost with in vitro culture. Strong antibody responses to PNSG were elicited in S. aureus infected mice, and a PNSG-capsule was observed by electron microscopy on isolates directly plated from infected kidneys. PNSG represents a previously unidentified surface polysaccharide of S. aureus that is elaborated during human and animal infection and is a prominent target for protective antibodies.

Identification of an osteogenic protein-1 (bone morphogenetic protein-7)-responsive element in the promoter of the rat insulin-like growth factor-binding protein-5 gene

Osteogenic protein-1 (OP-1), a member of the bone morphogenetic protein subfamily of the transforming growth factor-beta superfamily, induces new bone formation in vivo and regulates the expression of numerous growth factors. We previously showed that OP-1 down-regulates the transcription of the insulin-like growth factor-binding protein-5 (IGFBP-5) in primary cultures of fetal rat calvaria (FRC) cells. In the present study we identified, within the IGFBP-5 promoter, a 21-bp region that confers OP-1 responsiveness in FRC cells. Within this region lie three putative cis-acting regulatory elements, viz. a CAAT-like sequence, a CCAAT/enhancer-binding protein (C/EBPalpha)-like element, and a c-Myb or E-box-like motif. Mutations in the CAAT-like sequence reduced the promoter activity in both control and OP-1-treated cells, but did not abrogate the OP-1-induced down-regulation. Mutations in the C/EBPalpha-like element reduced the promoter activity in both control and OP-1-treated cells without significantly affecting the extent of down-regulation. Mutations in the putative c-Myb or E-box-like motif reduced the promoter activity in both the OP-1-treated and control cells and completely abolished the inhibitory effect of OP-1 on the IGFBP-5 promoter activity. Gel mobility shift analyses further showed specific interaction between nuclear protein(s) in FRC cells and the 21-bp region. OP-1 down-regulates the nuclear regulatory protein interaction with the 21-bp region by reducing either the cellular concentration of the regulatory protein(s) or the affinity of the regulatory protein(s) for the OP-1 responsive element. In conclusion, we identified an OP-1 response region in the rat IGFBP-5 promoter and further showed that OP-1 down-regulates the nuclear protein interaction with the response element(s).

Adherence of Staphylococcus aureus to endothelial cells: influence of capsular polysaccharide, global regulator agr, and bacterial growth phase

The adherence of Staphylococcus aureus to human endothelial cells (EC) is probably an important step in the pathogenesis of systemic staphylococcal infections. We examined the influence of type 5 capsular polysaccharide (CP5) production, the global regulator agr, and the bacterial growth phase on S. aureus adherence to EC. Whereas S. aureus Newman showed maximal adherence to EC in the logarithmic phase of growth, an isogenic agr mutant showed maximal adherence in the stationary growth phase. S. aureus adherence to EC and CP5 expression were negatively correlated: a mutation in the agr locus diminished CP5 production and led to increased adherence. Likewise, induction of CP5 expression by addition of NaCl to the growth medium resulted in reduced staphylococcal adherence to EC. S. aureus Newman cells that adhered to EC did not express CP5. A Newman cap5O mutant was acapsular and showed significantly greater adherence to EC than the parental strain did (P<0.005). Complementation of the cap5O mutation in trans restored CP5 expression and reduced EC adherence to a level similar to that of the parental strain. The enhanced adherence shown by the cap5O mutant was similar in magnitude to that of the agr mutant or the cap5O agr double mutant. Cells of the cap5O mutant and cap5O agr double mutant harvested from stationary-phase cultures adhered significantly better than did cells harvested in the exponential growth phase. These data are consistent with the postexponential and agr-independent expression by S. aureus of at least one putative EC adhesin, whose binding domain may be masked by CP5.

Prevention of nosocomial bloodstream infections: effectiveness of antimicrobial-impregnated and heparin-bonded central venous catheters

OBJECTIVES

To examine the effectiveness of antimicrobial-impregnated and heparin-bonded catheters relative to standard central venous catheters in lessening catheter-related bloodstream infections.

DATA SOURCES

Articles were identified by computer-assisted searching.

STUDY SELECTION

Studies were eliminated from further consideration if they did not contain original data relevant to lessening catheter-related bloodstream infections, were nonrandomized or uncontrolled, described subjects <17 yrs of age, or used animal subjects.

DATA ABSTRACTION

From each eligible article, we abstracted the following: a) citation; b) type of control; c) study setting; d) type of experimental catheter; e) catheter-specific complications; f) total numbers of patients and catheters; g) number of experimental catheters used that resulted in a catheter-related bloodstream infection; h) number of control catheters used that resulted in a catheter-related bloodstream infection; i) number of experimental catheters used without catheter-related bloodstream infections; and j) number of control catheters used without infections. We also recorded the duration of catheter use and the types of microbes cultured in association with the catheters and with catheter-related bloodstream infections.

DATA SYNTHESIS

Eleven eligible studies were identified. Using meta-analysis, we showed that antimicrobial-impregnated and heparin-bonded central venous catheters significantly decreased catheter-related bloodstream infections by 2.32% (95% confidence interval, 1.04% to 3.61%).

CONCLUSIONS

The modest additional cost for the use of these catheters relative to the considerable cost of treating even a single bloodstream infection makes their use cost-effective.

Identification of members of the genera Panaeolus and Psilocybe by a DNA test. A preliminary test for hallucinogenic fungi

Abuse of hallucinogens produced by the fungal genera Psilocybe and Panaeolus are a growing problem. Five species from each of the two genera were examined in this preliminary research and a method that will unambiguously identify fungal samples as being of one of these two genera has been developed. The method uses genus specific DNA sequences within the Internal Transcribed Spacer of the ribosomal gene complex. Amplification of a common DNA product and a genus specific product results in two identifiable products, which facilitates the unambiguous identification of material from these two fungi to generic level.

Age-related change of neuropeptide Y-immunoreactive neurons in the rat main olfactory bulb

The change of neuropeptide Y (NPY)-immunoreactive (IR) neurons in the rat main olfactory bulb as a result of aging was investigated at several aging stages over a two-year period; postnatal 1-24 months (P 1-P 24). From P 1 to P 12, the number of NPY-IR neurons and fibers increased with highest number in P 12, and the type of NPY-IR neurons had changed from bipolar neurons with short processes to bipolar/multipolar neurons with long processes. At P 24 the population of NPY-IR neurons and fibers had significantly decreased. Furthermore, the morphology of NPY-IR neurons showed a tendency to decrease in size and processes. It is suggested that the decrease of the number and size of NPY-IR neurons and fibers may underlie the age-related changes in the olfactory processes.

Quantification of self-recognition in multiple sclerosis by single-cell analysis of cytokine production

Identifying and quantifying autoaggressive responses in multiple sclerosis (MS) has been difficult in the past due to the low frequency of autoantigen-specific T cells, the high number of putative determinants on the autoantigens, and the different cytokine signatures of the autoreactive T cells. We used single-cell resolution enzyme-linked immunospot (ELISPOT) assays to study, directly ex vivo, proteolipid protein (PLP)-specific memory cell reactivity from MS patients and controls. Overlapping 9-aa-long peptides, spanning the entire PLP molecule in single amino acid steps, were used to determine the frequency and fine specificity of PLP-specific lymphocytes as measured by their IFN-gamma and IL-5 production. MS patients (n = 22) responded to 4 times as many PLP peptides as did healthy controls (n = 22). The epitopes recognized in individual patients, up to 22 peptides, were scattered throughout the PLP molecule, showing considerable heterogeneity among MS patients. Frequency measurements showed that the number of PLP peptide-specific IFN-gamma-producing cells averaged 11 times higher in MS patients than in controls. PLP peptide-induced IL-5-producing T cells occurred in very low frequencies in both MS patients and controls. This first comprehensive assessment of the anti-PLP-Th1/Th2 response in MS shows a greatly increased Th1 effector cell mass in MS patients. Moreover, the highly IFN-gamma-polarized, IL-5-negative cytokine profile of the PLP-reactive T cells suggests that these cells are committed Th1 cells. The essential absence of uncommitted Th0 cells producing both cytokines may explain why therapeutic strategies that aim at the induction of immune deviation show little efficacy in the established disease.

A meta-analysis of methylprednisolone in recovery from multiple sclerosis exacerbations

Despite recent advances in multiple sclerosis treatment, patients experience relapses for which standard treatment remains glucocorticosteroids (GCS). However, there is limited information comparing doses or routes of administration for different GCS types or the benefit of GCS compared to natural recovery. Currently, high dose (HD) methylprednisolone (MP) is the preferred therapy. We conducted meta-analyses of published studies assessing MP at different doses and in comparison to other steroid products or no treatment. Relevant studies were identified through predetermined processes and five articles met the inclusion criteria. Three studies compared HD MP to placebo; two studies compared the effect of HD MP and low dose (LD) MP; only one accepted report compared HD MP to another GCS. This report could not be included in a meta-analysis. The meta-analysis of HD MP vsplacebo studies indicated a mean treatment difference of 0.76 in Expanded Disability Status Score (EDSS) changes from baseline. The meta-analysis of HD and LD MP demonstrated no difference in EDSS change. Despite these rather obvious findings, these meta-analyses have been valuable in identifying further research questions. We recommend studies to determine optimum benefit related to dosage, timing for starting therapy and the most appropriate GCS type. Given the advances in MS therapeutics, these studies will have to include patients on additional disease modifying therapy. Multiple Sclerosis (2000) 6 267 - 273

Genetic and serologic evaluation of capsule production by bovine mammary isolates of Staphylococcus aureus and other Staphylococcus spp. from Europe and the United States

Bovine mastitis caused by Staphylococcus aureus is responsible for major economic losses to the dairy industry, and more-effective therapeutic or preventive approaches are sorely needed. The predominance of staphylococcal capsular polysaccharide types 5 and 8 among human isolates from many sources is well documented, but there seems to be a greater variation in the distribution of capsular serotypes among isolates from cows. A total of 636 isolates of S. aureus from cases of bovine mastitis in Sweden, Denmark, Finland, Iceland, Ireland, and the United States were investigated for production of capsular polysaccharide types 5 and 8. Approximately half of all the European isolates tested were of serotype 8, although variation among countries and among isolates of clinical and subclinical origin was observed. Sweden had the highest frequency (87%) of serotypeable isolates, and Finland had the lowest (48%). Capsule types 5 and 8 accounted for only 42% of the U.S. isolates tested. A few isolates showed weak reactivity with CP5 antiserum in a colony blot assay, and an enzyme-linked immunosorbent assay inhibition method confirmed that the levels of capsule produced by these strains were <10% of those produced by control strains. Fifty isolates that failed to react with capsular antisera all possessed the genes for production of capsular polysaccharide type 5 or 8. These results underscore the variability in capsule production by bovine isolates of S. aureus from different geographic regions. This information is important for the rational design of a capsule-based vaccine to prevent S. aureus bovine mastitis.

Microbiology of the prostate

Prostatitis is a common genitourinary disease in men. The National Institutes of Health has defined four types of prostatitis. The bacteriology of acute and chronic bacterial prostatitis is well understood. Causative organisms can be isolated by four-glass urine cultures. Chronic pelvic pain syndrome (CPPS; chronic abacterial prostatitis) is an enigma; whether there is a microbiologic cause for this condition is unknown. Researchers have postulated that CPPS may be an infectious disease of the prostate. This article reviews current literature regarding the microbiology of the prostate in CPPS.

The temporal and spatial expressions of neuropeptide Y induced by seizure in the hippocampal complex of gerbil

Recent studies reported changes in neuropeptide Y (NPY) expression induced by seizures in the experimental epileptic models. However, there have been few reports of the alteration of NPY expression in hippocampal complexes of genetic epilepsy models. In the present study, we performed spatial and temporal analyses of NPY expression in the hippocampal complexes of the seizure-resistant (SR) and seizure-sensitive (SS) gerbils, one of the genetic models. In SR gerbils, most NPY(+) cells were located at the dentate hilus (DH) and the subiculum (SC). In the pre-seizure group of SS gerbils, neurons in the DH and SC were nearly devoid of NPY immunoreactivity. Interestingly, the acute NPY expressions were observed in these areas of the post-seizure group at 30 min, and its immunoreactivity was declined at 12 h after the onset of seizure. These findings suggest that in seizure, the deficiency of NPY in DH and SC may be one of the factors, and that the acute expression of NPY after seizure in these areas may be the compensatory response for reduction of seizure activity in this animal.

Determination of sibship by PCR-amplified short tandem repeat analysis in Taiwan

BACKGROUND

Sibship determination for any two persons whose parents have died is one of the most fundamental issues of personal identification, second only to those of a parent-child relationship.

STUDY DESIGN AND METHODS

By automated fluorescence analysis of a PCR-amplified short tandem repeat (STR) system in conjunction with capillary electrophoresis, a panel of up to 15 polymorphic, autosomal, unlinked STR loci was used to investigate sibship index (SI) values in a cohort of 126 true sibling pairs. These SI values were then compared with those of 126 random pairs.

RESULTS

The 15-loci STR panel provides a cumulative power of exclusion of 0. 9999997. Of the 126 random pairs, 124 (98.4%) had cumulative sibship indices (CSIs) of <1.0, and none had a CSI of >3.0 (median, 0.0101; range, 0.0000003-2.5376). In contrast, 107 (85%) of the 126 sibling pairs had a CSI of >100 (median, 5,579.9853; range, 0.0747-9,406,829, 249.8461). However, five pairs (4%) of the sibling group had a CSI of <3.0. True sibship was confirmed for this particular group by additional paternity testing and mitochondrial DNA sequence analysis. Among a total of 1890 observations (15 loci x 126 pairs), two alleles per locus were shared 760 times (40.21%) (mean, 6.03 loci; range, 1-10) in the sibling group, but only 192 times (10.16%) in the random group (mean, 1.52 loci; range, 1-5) (p<0.001). No alleles were shared 696 times (36.83%) in the unrelated pairs, as compared to 176 times (9.31%) in the sibling group (p<0.001). A polarized distribution was not noted in the sharing of single alleles in either the random or the sibling group: 1002 observations (53.02%) and 954 observations (50.48%), respectively.

CONCLUSION

Highly polymorphic STR analysis can be discriminative in most sibship determinations, and the sharing of two alleles per locus is most informative in indicating sibship. Complementary mitochondrial DNA sequence analysis is mandatory in a few cases to exclude or establish true sibship when CSIs are equivocal and neither parent is available.

High resolution allelotype of microdissected primary nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a common cancer in South China but is rare in other parts of the world. To better understand the molecular basis of this cancer, we performed high-resolution allelotyping on 27 microdissected primary tumors using 382 microsatellite markers. We have detected high frequencies of allelic imbalance on 3p (96.3%), 9p (85.2%), 9q (88.9%), 11q (74.1%), 12q (70.4%), 13q (55.6%), 14q (85.2%), and 16q (55.6%). Nonrandom allelic changes of 12q and 16q were revealed for the first time. In addition, loss of heterozygosity on chromosomal arms 1p (37.0%), 5q (44.4%), and 12p (44.4%) were also common in NPC. Multiple minimally deleted regions, 7-40 cM, were identified at 3p14-24.2, 11q21-23, 13q12-14, 13q31-32, 14q24-32, and 16q22-23. Frequent deletions of these minimally deleted regions implied the presence of tumor suppressor genes that may be involved in the development of NPC. Consistent loss of heterozygosity on 3p, 9p, and 14q in almost all tumors suggested that such changes are critical events in NPC tumorigenesis.

Submasseteric abscess: report of two cases

Submasseteric abscess is a rare infection with the symptoms of cheek tenderness and marked trismus. Submasseteric abscess is located between the masseter muscle and mandibular ramus with different appearances as sepsis, infection, or tumor. Two cases of submasseteric abscess are reported along with symptoms, causes, and management techniques. Adequate drainage and antibiotic infusion are the treatment of choice. The differential diagnosis of cheek swelling and tenderness that should be considered are parotitis, parotid gland tumor, temporomasseter joint arthritis, and submasseteric abscess.

Ultra-wide band electromagnetic radiation does not affect UV-induced recombination and mutagenesis in yeast

Cell samples of the yeast Saccharomyces cerevisiae were exposed to 100 J/m2 of 254 nm ultraviolet (UV) radiation followed by a 30 min treatment with ultra-wide band (UWB) electromagnetic pulses. The UWB pulses (101-104 kV/m, 1.0 ns width, 165 ps rise time) were applied at the repetition rates of 0 Hz (sham), 16 Hz, or 600 Hz. The effect of exposures was evaluated from the colony-forming ability of the cells on complete and selective media and the number of aberrant colonies. The experiments established no effect of UWB exposure on the UV-induced reciprocal and non-reciprocal recombination, mutagenesis, or cell survival.

Amphibian Melanophore Technology as a Functional Screen for Antagonists of G-Protein Coupled 7-Transmembrane Receptors

Xenopus laevis melanophores stably expressing 7-transmembrane G-protein-coupled receptors were established and evaluated, either as a primary screening utility for antagonists of the human calcium receptor, or as a screen to assign function to binding inhibitors of human cannabinoid receptors. Stably or transiently expressing melanophores responded selectively to respective effectors of the human calcium, cannabinoid, and neurokinin-1 receptors. Several selective cannabinoid receptor-binding inhibitors of known potency were characterized as agonists or antagonists of the human peripheral cannabinoid (CB(2)) receptor. The results were consistent with changes in cAMP content of hCB(2)-transfected human embryonic kidney (HEK) cells challenged with the same CB(2)-binding antagonists. A stable melanophore cell line expressing the human calcium receptor was used to screen a compound collection directly for functional antagonists, several of which were confirmed as antagonists in secondary screens by stimulating parathyroid hormone (PTH) secretion from bovine parathyroid cells. The percentage of hits in this cell-based screen was reasonably low (1.2%), indicating minimal interference due to toxic effects and validating melanophores as a primary screening modality. Also described is the development of a novel procedure for cryopreservation and reconstitution of cells retaining functional human receptors. ()

Saccharomyces cerevisiae Yak1p protein kinase autophosphorylates on tyrosine residues and phosphorylates myelin basic protein on a C-terminal serine residue

The serine/threonine protein kinase, Yak1p, functions as a negative regulator of the cell cycle in Saccharomyces cerevisiae, acting downstream of the cAMP-dependent protein kinase. In the present work we report that overexpression of haemagglutinin-tagged full-lengthYak1p and an N-terminally truncated form (residues 148-807) lead to growth arrest in PKA compromised yak1 null yeast cells. Both forms of recombinant Yak1p kinase were catalytically active and preferred myelin basic protein (MBP) as a substrate over several other proteins. Phosphopeptide analysis of bovine MBP by tandem MS revealed two major Yak1p phosphorylation sites, Thr-97 and Ser-164. Peptides containing each site were obtained and tested as Yak1p substrates. Both forms of Yak1p phosphorylated a peptide containing the Ser-164 residue with far more efficient kinetics than MBP. The maximal velocity (V(max)) values of the full-length Yak1p reaction were 110+/-21 (Ser-164) and 8.7+/-1.7 (MBP), and those of N-terminally truncated Yak1p were 560.7+/-74.8 (Ser-164) and 34. 4+/-2.2 (MBP) pmol/min per mg of protein. Although neither form of Yak1p was able to phosphorylate two generic protein tyrosine kinase substrates, both were phosphorylated on tyrosine residues in vivo and underwent tyrosine autophosphorylation when reacted with ATP in vitro. Tandem MS showed that Tyr-530 was phosphorylated both in vivo and in vitro after reaction with ATP. Pre-treatment with protein tyrosine phosphatase 1B removed all of Yak1p phosphotyrosine content and drastically reduced Yak1p activity against exogenous substrates, suggesting that the phosphotyrosine content of the enzyme is essential for its catalytic activity. Although the N-terminally truncated Yak1p was expressed at a lower level than the full-length protein, its catalytic activity and phosphotyrosine content were significantly higher than those of the full-length enzyme. Taken together, our results suggest that Yak1p is a dual specificity protein kinase which autophosphorylates on Tyr-530 and phosphorylates exogenous substrates on Ser/Thr residues.

A 12-month review of autopsies performed at a university-affiliated teaching hospital in Hong Kong

OBJECTIVE

To review the autopsies performed at a university-affiliated teaching hospital over a 12-month period.

DATA SOURCES

Records of autopsies performed at a university-affiliated teaching hospital during 1997, and Medline literature search (1966-1998).

STUDY SELECTION

The key words used in the literature search were 'autopsy' and 'audit'.

DATA EXTRACTION

Data were extracted and analysed by the authors. Any discrepant cases (in which the final diagnoses were either unexpected or not made before death) were identified from the hospital records.

DATA SYNTHESIS

Interest in autopsy results has increased, owing to the greater emphasis on medical audit and quality assurance procedures. Of the yearly total of 403 autopsies, 332 cases were reviewed; the discrepancies found were classified as either major or minor, according to their effect on the clinical outcome. The major and minor discrepancy rates were 23% and 9%, respectively. In 2% of cases, the cause of death was due to complications resulting from surgical intervention. These discrepancy rates were comparable to the figures quoted in the literature.

CONCLUSION

Autopsy is a valid medical quality-assurance mechanism in Hong Kong.

REDK, a novel human regulatory erythroid kinase

We have identified a novel regulatory erythroid kinase (REDK) that is homologous to a family of dual-specificity kinases. The yeast homolog of REDK negatively regulates cell division, suggesting a similar function for REDK, which is primarily localized in the nucleus. REDK is present in hematopoietic tissues, such as bone marrow and fetal liver, but the RNA is expressed at significant levels only in erythroid or erythropoietin (EPO)-responsive cells. Two novel forms of cDNA (long and short) for REDK have been isolated that appear to be alternative splice products and imply the presence of polypeptides with differing amino termini. The ratio of short-to-long forms of REDK increases dramatically in CD34(+) cells cultured with EPO, suggesting differing regulation and function for each form. REDK is predominantly found in nuclear, rather than cytoplasmic, protein extracts, and immunoprecipitated REDK is active in phosphorylating histones H2b, H3, myelin basic protein, and other coimmunoprecipitated proteins. Antisense REDK oligonucleotides promote erythroid colony formation by human bone marrow cells, without affecting colony-forming unit (CFU)-GM, CFU-G, or CFU-GEMM numbers. Maximal numbers of CFU-E and burst-forming unit-erythroid were increased, and CFU-E displayed increased sensitivity to suboptimal EPO concentrations. The data indicate that REDK acts as a brake to retard erythropoiesis. (Blood. 2000;95:2838-2846)

Effect of hemodialysis on plasma nitric oxide levels

Nitric oxide (NO) is produced in excess in various pathological states, including sepsis and hepatic cirrhosis, and appears to be related to inflammatory status. In uremia, one would expect the levels of NO to increase. We aimed to determine whether hemodialysis (HD) would remove NO from the systemic circulation of uremic patients. Blood was collected before, after, and 1 day after HD from 12 uremic patients. Plasma nitrite and nitrate (NOx-) levels were measured by colorimetric Greiss reaction and cGMP was measured by an enzyme immunoassay kit. Our study demonstrated that uremic patients have high plasma NO levels, and HD led to a significant drop in plasma NOx- level (63 +/- 15% reduction). The level rose back to the pre-HD level on the following day. Plasma cGMP in the patients also decreased significantly after HD (27 +/- 14% reduction). In conclusion, we hypothesized that HD might be a possible approach for the removal of excess NO in pathological conditions such as sepsis and hepatic cirrhosis.

Inhibition of p38 MAP kinase as a therapeutic strategy

Since the discovery of p38 MAP kinase in 1994, our understanding of its biology has progressed dramatically. The key advances include (1) identification of p38 MAP kinase homologs and protein kinases that act upstream and downstream from p38 MAP kinase, (2) identification of interesting and potentially important substrates, (3) elucidation of the role of p38 MAP kinase in cellular processes and (4) the establishment of the mechanism by which the pyridinylimidazole p38 MAP kinase inhibitors inhibit enzyme activity. It is now known that there are four members of the p38 MAP kinase family. They differ in their tissue distribution, regulation of kinase activation and subsequent phosphorylation of downstream substrates. They also differ in terms of their sensitivities toward the p38 MAP kinase inhibitors. The best-studied isoform is p38 alpha, whose activation has been observed in many hematopoietic and non-hematopoietic cell types upon treatment with appropriate stimuli. The pyridinylimidazole compounds, exemplified by SB 203580, were originally prepared as inflammatory cytokine synthesis inhibitors that subsequently were found to be selective inhibitors of p38 MAP kinase. SB 203580 inhibits the catalytic activity of p38 MAP kinase by competitive binding in the ATP pocket. X-ray crystallographic studies of the target enzyme complexed with inhibitor reinforce the observations made from site-directed mutagenesis studies, thereby providing a molecular basis for understanding the kinase selectivity of these inhibitors. The p38 MAP kinase inhibitors are efficacious in several disease models, including inflammation, arthritis and other joint diseases, septic shock, and myocardial injury. In all cases, p38 activation in key cell types correlated with disease initiation and progression. Treatment with p38 MAP kinase inhibitors attenuated both p38 activation and disease severity. Structurally diverse p38 MAP kinase inhibitors have been tested extensively in preclinical studies.

Identification of hallucinogenic fungi from the genera Psilocybe and Panaeolus by amplified fragment length polymorphism

Unambiguous identification of the hallucinogenic fungi of the genera Psilocybe and Panaeolus is required by national and international drug control legislation. We report on a DNA-based test using the technique of amplified fragment length polymorphism (AFLP). AFLP can differentiate species of the two genera Psilocybe and Panaeolus by using different primer sets. The identification of hallucinogenic fungi using a DNA-based test, which can be used in conjunction with morphological features, will assist in forensic investigations.

Prognostic value of vascular endothelial growth factor expression in colorectal cancer patients

Solid tumours require neovascularisation for growth and metastasis. Vascular endothelial growth factor (VEGF) has been shown to be an important regulator of tumour angiogenesis. To examine the relevance of VEGF in the neoplastic transformation of human colon, we analysed protein expression in a total 30 polyps and 145 colorectal carcinomas by immunohistochemistry. All adenoma specimens, regardless of histological differentiation, and normal colonic mucosa did not express VEGF. Amongst 90 patients with non-metastatic colorectal cancer, VEGF expression was observed in 43 (48%) cases, whilst 29 of the 55 patients (53%) with metastases expressed the angiogenic factor. Both the proportion and intensity of VEGF expression were positively associated with the progression of colon carcinogenesis. Tumours with the highest VEGF expression tended to correlate with patients' survival, although VEGF expression did not emerge as an independent risk factor in a multivariate analysis. After exclusion of the patients with distant metastases, both univariate and multivariate analysis did not indicate any prognostic value for the tissues with the highest VEGF expression. Our results suggest that VEGF may play a role in the progression of colon cancer, although evaluation of this angiogenic phenotype did not provide additional prognostic information compared with that obtained from Dukes' staging of the tumours.

Gliogenesis in the central nervous system

Multipotential neuroepithelial stem cells are thought to give rise to all the differentiated cells of the central nervous system (CNS). The developmental potential of these multipotent stem cells becomes more restricted as they differentiate into progressively more committed cells and ultimately into mature neurons and glia. In studying gliogenesis, the optic nerve and spinal cord have become invaluable models and the progressive stages of differentiation are being clarified. Multiple classes of glial precursors termed glial restricted precursors (GRP), oligospheres, oligodendrocyte-type2 astrocyte (O-2A) and astrocyte precursor cells (APC) have been identified. Similar classes of precursor cells can be isolated from human neural stem cell cultures and from embryonic stem (ES) cell cultures providing a non-fetal source of such cells. In this review, we discuss gliogenesis, glial stem cells, putative relationships of these cells to each other, factors implicated in gliogenesis, and therapeutic applications of glial precursors.

SB 239063, a potent p38 MAP kinase inhibitor, reduces inflammatory cytokine production, airways eosinophil infiltration, and persistence

The anti-inflammatory/antiallergic activity of a novel second-generation p38 mitogen-activated protein kinase inhibitor, SB 239063[trans-1-(4-hydroxycyclohexyl) -4-(4-fluorophenyl)-5-(2-methoxypyridimidin-4-yl)imidazole], was investigated in vivo and in vitro. SB 239063 had an IC(50) of 44 nM for inhibition of recombinant purified human p38alpha. In lipopolysaccharide-stimulated human peripheral blood monocytes, SB 239063 inhibited interleukin-1 and tumor necrosis factor-alpha production (IC(50) values = 0.12 and 0.35 microM, respectively). A role for p38 kinase in cytokine-associated inflammation in the mouse was shown by p38 activation in the lung and inhibition of lipopolysaccharide-induced tumor necrosis factor-alpha production by SB 239063 (ED(50) = 5.8 mg/kg p.o.). Antiallergic activity was demonstrated by essential abolition (approximately 93% inhibition) of inhaled ovalbumin (OA)-induced airway eosinophilia by SB 239063 (12 mg/kg p.o.), measured by bronchoalveolar lavage (BAL) in OA-sensitized mice. In addition, p38 kinase was found by Western analysis to be activated in guinea pig lung. Administration of SB 239063 (10 or 30 mg/kg p.o.) in conscious guinea pigs markedly reduced ( approximately 50% inhibition) OA-induced pulmonary eosinophil influx, measured by BAL 24 h after antigen. SB 239063 (10 mg/kg b.i.d. p.o.) administered after leukotriene D(4) inhalation, reduced by 60% the persistent airway eosinophilia seen at 4 days. Apoptosis of cultured eosinophils isolated from guinea pig BAL was increased by SB 239063 (1-10 microM) in the presence of interleukin-5. These results indicate that SB 239063 is a potent inhibitor of inflammatory cytokine production, inhibits eosinophil recruitment, in addition to enhancing apoptosis of these cells. Collectively, the results support the potential utility of p38 kinase inhibitors, such as SB 239063, for the treatment of asthma and other inflammatory disorders.

Inhibition of extracellular signal-regulated kinase enhances Ischemia/Reoxygenation-induced apoptosis in cultured cardiac myocytes and exaggerates reperfusion injury in isolated perfused heart

Three major mammalian mitogen-activated protein kinases, extracellular signal-regulated kinase (ERK), p38, and c-Jun NH(2)-terminal protein kinase (JNK), have been identified in the cardiomyocyte, but their respective roles in the heart are not well understood. The present study explored their functions and cross talk in ischemia/reoxygenation (I/R)-induced cardiac apoptosis. Exposing rat neonatal cardiomyocytes to ischemia resulted in a rapid and transient activation of ERK, p38, and JNK. On reoxygenation, further activation of all 3 mitogen-activated protein kinases was noted; peak activities increased (fold) by 5.5, 5.2, and 6.2, respectively. Visual inspection of myocytes exposed to I/R identified 18.6% of the cells as showing morphological features of apoptosis, which was further confirmed by DNA ladder and terminal deoxyribonucleotide transferase-mediated dUTP nick end labeling (TUNEL). Myocytes treated with PD98059, a MAPK/ERK kinase (MEK1/MEK2) inhibitor, displayed a suppression of I/R-induced ERK activation, whereas p38 and JNK activities were increased by 70.3% and 55.0%, respectively. In addition, the number of apoptotic cells was increased to 33.4%. With pretreatment of cells with SB242719, a selective p38 inhibitor, or SB203580, a p38 and JNK2 inhibitor, I/R+PD98059-induced apoptotic cells were reduced by 42.8% and 63.3%, respectively. Hearts isolated from rats treated with PD98059 and subjected to global ischemia (30 minutes)/reoxygenation (1 hour) showed a diminished functional recovery compared with the vehicle group. Coadministration of SB203580 attenuated the detrimental effects of PD98059 and significantly improved cardiac functional recovery. The data taken together suggest that ERK plays a protective role, whereas p38 and JNK mediate apoptosis in cardiomyocytes subjected to I/R, and the dynamic balance of their activities is critical in determining cardiomyocyte fate subsequent to reperfusional injury.

Aberrant p15 promoter methylation in adult and childhood acute leukemias of nearly all morphologic subtypes: potential prognostic implications

We prospectively analyzed p15 and p16 promoter methylation patterns using methylation-specific polymerase chain reaction (PCR) in patients with adult and childhood acute leukemias and studied the association of methylation patterns with chromosomal abnormalities and prognostic variables. In nearly all French-American-British leukemia subtypes, we found p15 methylation in bone marrow or peripheral blood cells from 58% (46/79) of patients with acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), or acute biphenotypic leukemia (ABL). An identical alteration was detected in blood plasma from 11 of 12 of these patients (92%). We also demonstrated for the first time concomitant p16 and p15 methylation in 22% (8/37) of adults with AML or ALL, exclusively in those with M2, M4, or L2 subtypes. According to cytogenetic data from 35 patients with ALL, AML, or ABL, 82% (14/17) of those with unmethylated p15 alleles had normal karyotypes or hyperdiploidies associated with a favorable prognosis. Conversely, 44% (8/18) of patients with p15 methylation had chromosomal translocations, inversions, or deletions, suggesting an interplay of these abnormalities with p15 methylation. As a prognostic marker for disease monitoring, p15 methylation appears to be more widely applicable than BCR-ABL, AF4-MLL, and AML1-ETO transcripts, which were detectable in only 8% (4/48) of patients by reverse transcriptase-PCR. Thirty-nine of 43 blood samples (91%) sequentially collected from 12 patients with AML, ALL, or ABL showed p15 methylation status in excellent concordance with morphologic disease stage. Early detection of p15 methylation at apparent remission or its acquisition during follow-up may prove valuable for predicting relapse. Overall survival of patients with p15 methylation was notably shortened among 38 adults with AML and 12 adults with ALL. Aberrant p15 methylation may have important prognostic implications for clinical monitoring and risk assessment. (Blood. 2000;95:1942-1949)

Systematic variation in gene expression patterns in human cancer cell lines

We used cDNA microarrays to explore the variation in expression of approximately 8,000 unique genes among the 60 cell lines used in the National Cancer Institute's screen for anti-cancer drugs. Classification of the cell lines based solely on the observed patterns of gene expression revealed a correspondence to the ostensible origins of the tumours from which the cell lines were derived. The consistent relationship between the gene expression patterns and the tissue of origin allowed us to recognize outliers whose previous classification appeared incorrect. Specific features of the gene expression patterns appeared to be related to physiological properties of the cell lines, such as their doubling time in culture, drug metabolism or the interferon response. Comparison of gene expression patterns in the cell lines to those observed in normal breast tissue or in breast tumour specimens revealed features of the expression patterns in the tumours that had recognizable counterparts in specific cell lines, reflecting the tumour, stromal and inflammatory components of the tumour tissue. These results provided a novel molecular characterization of this important group of human cell lines and their relationships to tumours in vivo.

Mutation of a unique aspartate residue abolishes the catalytic activity but not substrate binding of the mouse N-methylpurine-DNA glycosylase (MPG)

N-Methylpurine-DNA glycosylase (MPG) initiates base excision repair in DNA by removing a variety of alkylated purine adducts. Although Asp was identified as the active site residue in various DNA glycosylases based on the crystal structure, Glu-125 in human MPG (Glu-145 in mouse MPG) was recently proposed to be the catalytic residue. Mutational analysis for all Asp residues in a truncated, fully active MPG protein showed that only Asp-152 (Asp-132 in the human protein), which is located near the active site, is essential for catalytic activity. However, the substrate binding was not affected in the inactive Glu-152, Asn-152, and Ala-152 mutants. Furthermore, mutation of Asp-152 did not significantly affect the intrinsic tryptophan fluorescence of the enzyme and the far UV CD spectra, although a small change in the near UV CD spectra of the mutants suggests localized conformational change in the aromatic residues. We propose that in addition to Glu-145 in mouse MPG, which functions as the activator of a water molecule for nucleophilic attack, Asp-152 plays an essential role either by donating a proton to the substrate base and, thus, facilitating its release or by stabilizing the steric configuration of the active site pocket.

Identification of victims of the 1998 Taoyuan Airbus crash accident using DNA analysis

In February 1998 a civilian aeroplane carrying 196 individuals crashed in Taiwan and killed another 6 people on the ground. Although there were dental and medical records, fingerprints, photographic evidence and personal effects to identify some of the victims, DNA analysis was required to further identify severely damaged remains. From the 202 people known to have perished in the plane crash, a total of 685 fragments of human remains were subjected to DNA analysis. The analysis was carried out using nine microsatellite loci, plus amelogenin to cluster the 685 fragments into 202 groups, accounting for all the victims. To establish genetic relatedness of the victims to other victims and living relatives, additional DNA loci were used. In this case the paternity index was increased by using HLA DQA1 plus Polymarker. The same 16 DNA loci were used to test blood samples from 201 relatives to establish parent/child and sibling relationships. With the exception of 19 victims identified by non-genetic evidence, 183 victims were successfully identified by DNA typing with relatively high values of paternity index by the direct or indirect comparison of relatives. The 202 victims were from 37 different families, ranging in size from 2 to 13 members and 74 individuals known to be unrelated to any other victim. The DNA from living relatives was used to identify one member of a family group, from which other victims of the family could be identified. ABO blood group information was further used to confirm genetic relatedness within families. A comparison of the DNA profiling results to the ABO blood group of the victims showed no discrepancies with the exception of two mutations in the FGA locus. In cases of severely damaged victims from a plane crash, DNA analysis proved to be the best choice to identify victims.

Capsule expression by bovine isolates of Staphylococcus aureus from Argentina: genetic and epidemiologic analyses

Staphylococcus aureus is an important cause of bovine mastitis worldwide, and effective preventive or therapeutic modalities are lacking. Although most human S. aureus isolates produce capsular polysaccharides (CPs), few reports have described the prevalence of capsules on bovine isolates. This information is important for the rational design of a vaccine for the prevention of staphylococcal mastitis. We serotyped 195 S. aureus strains isolated between 1989 and 1997 from the milk of mastitic cows in Argentina. Only 14 (7.1%) of the strains were serotype 5, and all were recovered between 1989 and 1992. Thirteen serotype 8 strains were identified, and 12 of these were isolated between 1991 and 1994. The remaining 168 isolates were nonreactive (NR) with CP serotype 5 (CP5)- or CP8-specific antibodies. Hybridization studies performed with genomic DNA from eight NR strains revealed that only three of them carried the capsule genes. Pulsed-field gel electrophoresis (PFGE) performed with 127 of the 195 S. aureus isolates revealed that most (86%) strains belonged to one of four major PFGE groups. Although 8 of 14 CP5 isolates showed a common PFGE pattern (arbitrarily defined as A1), 31 other A1 isolates from the same time period (1989 to 1992) were not CP5 positive. In contrast, only nine PFGE type B3 isolates were recovered between 1990 and 1994, and eight of these were positive for CP8 (P < 0.0003). The results of this study underscore the variability in capsule expression by S. aureus strains isolated from different geographical regions and cast doubt on the roles of CP5 and CP8 in the pathogenesis and immunoprophylaxis of bovine mastitis in Argentina.

Rapid identification of the ABO genotypes by their single-stand conformation polymorphism

The ABO locus on chromosome 9 contains many more alleles than are currently used routinely in forensic science. The use of single-strand conformation polymorphism (SSCP) can separate sequence polymorphisms that differ by only one base. The SSCP process used allows for both single- and double-stranded polymerase chain reaction (PCR) products to be visualized. The six ABO genotypes can be differentiated by the allele-specific B and O SSCP patterns. The double-stranded DNA produced 'hybrid' bands due to heterozygous samples and allowed sequence diversity to be detected between alleles of heterozygotes. These 'hybrid' bands are valid markers to confirm genotypes of specimens.

Reversion of the glycopeptide resistance phenotype in Staphylococcus aureus clinical isolates

The recent identification of glycopeptide intermediate-resistant Staphylococcus aureus (GISA) clinical isolates has provided an opportunity to assess the stability of the glycopeptide resistance phenotype by nonselective serial passage and to evaluate reversion-associated cell surface changes. Three GISA isolates from the United States (MIC of vancomycin = 8 microg/ml) and two from Japan (MICs of vancomycin = 8 and 2 microg/ml) were passaged daily on nutrient agar with or without vancomycin supplementation. After 15 days of passage on nonselective medium, vancomycin- and teicoplanin-susceptible revertants were obtained from each GISA isolate as determined by broth dilution MIC. Revertant isolates were compared with parent isolates for changes in vancomycin heteroresistance, capsule production, hemolysis phenotype, coagulase activity, and lysostaphin susceptibility. Several revertants lost the subpopulations with intermediate vancomycin resistance, whereas two revertants maintained them. Furthermore, although all of the parent GISA isolates produced capsule type 5 (CP5), all but one revertant tested no longer produced CP5. In contrast, passage on medium containing vancomycin yielded isolates that were still intermediately resistant to vancomycin, had no decrease in the MIC of teicoplanin, and produced detectable CP5. No consistent changes in the revertants in hemolysis phenotype, lysostaphin susceptibility, or coagulase activities were discerned. These data indicate that the vancomycin resistance phenotype is unstable in clinical GISA isolates. Reversion of the vancomycin resistance phenotype might explain the difficulty in isolating vancomycin-resistant clinical isolates from the blood of patients who fail vancomycin therapy and, possibly, may account for some of the difficulties in identifying GISA isolates in the clinical laboratory.

Biopharmaceutical formulation

The rapid maturation of the field of biopharmaceutical formulation is the result of the simultaneous development of a thermodynamic mechanism for protein-solvent interaction and identification of natural chemicals employed by nature to stabilize proteins in response to environmental stresses. In general, these cosolvents are excluded from the protein surface. Proteins are maintained in their native folded conformations by these cosolvents as a result of the highly unfavorable interaction between cosolvents and peptide backbones, which would be exposed to the cosolvent upon unfolding.

Spatially variant apodization for image reconstruction from partial Fourier data

Sidelobe artifacts are a common problem in image reconstruction from finite-extent Fourier data. Conventional shift-invariant windows reduce sidelobe artifacts only at the expense of worsened mainlobe resolution. Spatially variant apodization (SVA) was previously introduced as a means of reducing sidelobe artifacts, while preserving mainlobe resolution. Although the algorithm has been shown to be effective in synthetic aperture radar (SAR), it is heuristically motivated and it has received somewhat limited analysis. In this paper, we show that SVA is a version of minimum-variance spectral estimation (MVSE). We then present a complete development of the four types of two-dimensional SVA for image reconstruction from partial Fourier data. We provide simulation results for various real-valued and complex-valued targets and point out some of the limitations of SVA. Performance measures are presented to help further evaluate the effectiveness of SVA.

Disease-modifying activity of SB 242235, a selective inhibitor of p38 mitogen-activated protein kinase, in rat adjuvant-induced arthritis

OBJECTIVE

To evaluate the effects of SB 242235, a potent and selective inhibitor of p38 mitogen-activated protein (MAP) kinase, on joint integrity in rats with adjuvant-induced arthritis (AIA).

METHODS

Male Lewis rats with AIA were orally treated either prophylactically (days 0-20) or therapeutically (days 10-20) with SB 242235. Efficacy was determined by measurements of paw inflammation, dual-energy x-ray absorptiometry for bone-mineral density (BMD), magnetic resonance imaging (MRI), microcomputed tomography (CT), and histologic evaluation. Serum tumor necrosis factor alpha (TNFalpha) in normal (non-AIA) rats and serum interleukin-6 (IL-6) levels in rats with AIA were measured as markers of the antiinflammatory effects of the compound.

RESULTS

SB 242235 inhibited lipopolysaccharide-stimulated serum levels of TNFalpha in normal rats, with a median effective dose of 3.99 mg/kg. When SB 242235 was administered to AIA rats prophylactically on days 0-20, it inhibited paw edema at 30 mg/kg and 10 mg/kg per day by 56% and 33%, respectively. Therapeutic administration on days 10-20 was also effective, and inhibition of paw edema was observed at 60, 30, and 10 mg/kg (73%, 51%, and 19%, respectively). Significant improvement in joint integrity was demonstrated by showing normalization of BMD and also by MRI and micro-CT analysis. Protection of bone, cartilage, and soft tissues was also shown histologically. Serum IL-6 levels were decreased in AIA rats treated with the 60 mg/kg dose of compound.

CONCLUSION

Symptoms of AIA in rats were significantly reduced by both prophylactic and therapeutic treatment with the p38 MAP kinase inhibitor, SB 242235. Results from measurements of paw inflammation, assessment of BMD, MRI, and micro-CT indicate that this compound exerts a protective effect on joint integrity, and thus appears to have disease-modifying properties.

Specific inhibition of cyclooxygenase 2 restores antitumor reactivity by altering the balance of IL-10 and IL-12 synthesis

Cyclooxygenase-2 (COX-2), the enzyme at the rate-limiting step of prostanoid production, has been found to be overexpressed in human lung cancer. To evaluate lung tumor COX-2 modulation of antitumor immunity, we studied the antitumor effect of specific genetic or pharmacological inhibition of COX-2 in a murine Lewis lung carcinoma (3LL) model. Inhibition of COX-2 led to marked lymphocytic infiltration of the tumor and reduced tumor growth. Treatment of mice with anti-PGE2 mAb replicated the growth reduction seen in tumor-bearing mice treated with COX-2 inhibitors. COX-2 inhibition was accompanied by a significant decrement in IL-10 and a concomitant restoration of IL-12 production by APCs. Because the COX-2 metabolite PGE2 is a potent inducer of IL-10, it was hypothesized that COX-2 inhibition led to antitumor responses by down-regulating production of this potent immunosuppressive cytokine. In support of this concept, transfer of IL-10 transgenic T lymphocytes that overexpress IL-10 under control of the IL-2 promoter reversed the COX-2 inhibitor-induced antitumor response. We conclude that abrogation of COX-2 expression promotes antitumor reactivity by restoring the balance of IL-10 and IL-12 in vivo.

A second-site mutation at glutamate-257 that restores the function of the mutant yeast ribosomal protein L5 containing lysine-270,271-->arginine

A genetic approach was used to identify interacting regions of yeast ribosomal protein L5 (also known as L1, L1a, or YL3). Previous studies from our laboratory showed that residues K270 and K271 in protein L5 are essential for its function. The mutant L5 protein in which both residues were replaced by arginine residues (K270,271R) exhibited about 80% RNA binding capability compared to the wild-type and the mutant protein was assembled into the 60S ribosomal subunits in vivo. The yeast strain expressing this mutant protein in a homozygous form was lethal (Biochim. Biophys. Acta 1308 (1996) 133-141). In the present study, this non-functional mutant was used to select intragenic suppressors. A spontaneous, intragenic suppressor which contained an E257K substitution (in addition to the primary mutations) was identified. The suppressor protein bound about 60% of yeast 5S rRNA in vitro compared to the wild-type. To gain more insight into the nature of the intragenic suppressor, additional mutant proteins in which E257 was substituted by a variety of amino acids were produced by site-directed mutagenesis. The ability of each mutant protein to bind yeast 5S rRNA in vitro and to suppress the lethal effect of the double K270,271 mutation in vivo were examined. Results suggest communication between two non-contiguous domains on protein L5 and that several factors, such as electrostatic interaction and hydrogen bonding are likely to play a role in this global communication. Mutation studies on E257 alone also reveal that substitutions of this residue in L5 protein could affect cell growth under specified conditions, but a variety of changes could be tolerated without serious deleterious effects. We propose a working model in which E257 is located in a loop and the dynamic as well as the flexibility of this loop is important for L5 function.

Photonic defect modes of cholesteric liquid crystals

We investigate defect modes of cholesteric liquid crystals as photonic band gap materials. For normal incidence of light, cholesteric liquid crystals exhibit total reflection for the circular polarization with the same handedness as that of cholesteric helix. However, the other orthogonal component is completely transmitted. When we replace a thin layer of liquid crystal by an isotropic material as a defect, defect modes are induced for both polarizations of incident light. We analyze the wavelength and reflectivity of the defect modes in terms of the refractive index of defect layer.

Inhibiting tumorigenic potential by restoration of p16 in nasopharyngeal carcinoma

The p16 gene, encodes a key checkpoint protein p16 in the cell cycle, has been reported inactivation in a wide variety of human cancers. We have previously demonstrated high frequency of p16 alterations in primary nasopharyngeal carcinoma (NPC), xenografts and cell lines. The finding implied that inactivation of the p16 gene may play an important role in the NPC development. To investigate the tumour suppressor function of p16 in NPC, we transfected p16-deficient NPC cell line, NPC/HK-1, with a wild-type p16 expression construct, and evaluated growth and tumorigenic properties of the clones stably expressing exogenous p16. Expression of the exogenous wild-type p16 significantly inhibited cell growth by more than 70% when compared to that of the parental and empty vector-transfected cells. This growth inhibition was attributable to a significant proportion of p16-expressing cells arrested at G1 phase in the cell cycle as revealed by flow cytometric analysis. By anchorage-independent colony forming assay, we found that the ability to form colonies in soft agar was highly reduced in cells expressing p16. NPC/HK1 cells expressing functional p16 also showed suppressed tumorigenicity in athymic nude mice. Taken together, our results provide strong evidence for a tumour suppressor role of p16 in NPC.

Improved recovery of Mycobacterium tuberculosis from pleural aspirates: bedside inoculation, heparinized containers and liquid culture media

The effects of bedside inoculation, heparinized containers and liquid culture media on the recovery of Mycobacterium tuberculosis from pleural aspirates were evaluated in this study. Of 155 patients, 63 were diagnosed to have pleural effusion tuberculous in origin. The overall recovery of M. tuberculosis was 57.1%. Bedside inoculation of the specimens produced a significantly higher yield than laboratory inoculation using non-heparinized specimens. When the pleural aspirates were transported in heparinized containers, the recovery rate was comparable to that from bedside inoculation, but lower when non-heparinized containers were used. No significant difference was found in recovery rate between the two liquid media, but the rate was significantly higher with the use of liquid media than conventional solid media. Thus, bedside inoculation of pleural aspirates, use of heparinized containers for transport for delayed inoculation in the laboratory and use of liquid culture media are recommended.

Use of the brain parenchymal fraction to measure whole brain atrophy in relapsing-remitting MS. Multiple Sclerosis Collaborative Research Group

BACKGROUND

Episodic inflammation in the CNS during the early stages of MS results in progressive disability years later, presumably due to myelin and axonal injury. MRI demonstrates ongoing disease activity during the early disease stage, even in some patients who are stable clinically. The optimal MRI measure for the destructive pathologic process is uncertain, however.

METHODS

In this post-hoc study, MRI scans were analyzed from patients with relapsing MS participating in a placebo-controlled trial of interferon beta-1a. The brain parenchymal fraction, defined as the ratio of brain parenchymal volume to the total volume within the brain surface contour, was used to measure whole brain atrophy. The relationship between disease features and brain atrophy and effect of interferon beta-1a were determined.

RESULTS

MS patients had significant brain atrophy that worsened during each of 2 years of observation. In many patients, brain atrophy worsened without clinical disease activity. Baseline clinical and MRI abnormalities were not strongly related to the rate of brain atrophy during the subsequent 2 years. Treatment with interferon beta-1a resulted in a reduction in brain atrophy progression during the second year of the clinical trial.

CONCLUSIONS

Patients with relapsing-remitting MS have measurable amounts of whole brain atrophy that worsens yearly, in most cases without clinical manifestations. The brain parenchymal fraction is a marker for destructive pathologic processes ongoing in relapsing MS patients, and appears useful in demonstrating treatment effects in controlled clinical trials.

In vitro assembly of yeast 5S rRNA and a fusion protein containing ribosomal protein L5 and maltose binding protein

Binding of yeast ribosomal protein L5 with 5S rRNA has long been considered a promising model for studying molecular mechanisms of protein-RNA interactions. However, in vitro assembly of a ribonucleoprotein (RNP) complex from purified yeast ribosomal protein L5 (also known as L1, L1a, or YL3) and 5S rRNA proved to be difficult, thus limiting the utility of this model. In the present report, we present data on the successful in vitro assembly of a RNP complex using a fusion (MBP-L5) protein consisting of the yeast ribosomal protein L5 fused to the carboxyl terminus of the E. coli maltose-binding protein (MBP). We demonstrated that: 1) the MBP-L5 protein binds yeast 5S rRNA but not 5.8S rRNA in vitro; 2) the MBP protein itself does not bind yeast 5S rRNA; 3) formation of the RNP complex is proportional to the concentration of MBP-L5 protein and 5S rRNA; and 4) the MBP moiety of the fusion protein in the RNP complex can be removed with factor Xa. The electrophoretic mobility of the resultant RNP complex is indistinguishable from that of L5-5S rRNA complex isolated from the ribosome. Using this new experimental approach, we further showed that the RNA binding capability of a mutant L5 protein is decreased by 60% compared to the wild-type protein. Additionally, the mutant RNP complex migrates slower than the wild-type RNP complex suggesting that the mutant RNP complex has a less compact conformation. The finding provides a probable explanation for an earlier observation that the 60S ribosomal subunit containing the mutant protein is unstable.

Quantitative and temporal correlation between circulating cell-free Epstein-Barr virus DNA and tumor recurrence in nasopharyngeal carcinoma

Recently, cell-free EBV DNA has been detected in the plasma and serum of patients with nasopharyngeal carcinoma (NPC). We studied the relationship between plasma/serum EBV DNA and tumor recurrence. Using real-time quantitative PCR, the median plasma EBV DNA concentration in 10 patients with tumor recurrence was determined to be 32,350 copies/ml, whereas that in 15 patients in continuous remission for a mean period of 2 years was 0 copy/ml. Longitudinal follow-up of 17 NPC patients revealed 6 individuals with tumor recurrence and 11 patients who remained in remission. Significant elevations in serum EBV DNA, sometimes up to 6 months before detectable clinical deterioration, were observed in the patients who subsequently developed tumor recurrence. Continuously low or undetectable levels of serum EBV DNA were observed in the patients who remained in remission. These results suggest that plasma/serum cell-free EBV DNA may be a valuable tool for the monitoring of NPC patients for the early detection of tumor recurrence.

Two distinct regions of deletion on chromosome 13q in primary nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is rare in most parts of the world, but prevalent in Southern China. Although this disease poses a serious health problem in our population, the genetic alterations that lead to the development of NPC have yet to be defined. In a comparative genomic hybridization (CGH) study on NPC by our group, loss of the long arm of chromosome 13 has been identified as a frequent event. To investigate further the involvement of this genetic alteration in NPC tumorigenesis, we examined 31 primary NPC tumours by LOH analysis with a panel of 13 microsatellite polymorphic markers distributed along the long arm of chromosome 13. It was found that 19/31 tumours (60%) showed LOH for markers on chromosome 13q. The highest frequency of LOH was found at loci D13S133 (53.6%) on 13q14.3 and D13S796 (38.5%) on 13q32-34. Two distinct smallest deletion regions were delineated: the first region between D13S133 and D13S119 at 13q14.3-22, and the second region between D13S317 and D13S285 at 13q31-34. Our findings show that LOH of 13q is a common event in NPC and that at least 2 putative tumour-suppressor loci may be present on 13q. Mapping of the critical regions of these loci suggests that some candidate tumour-suppressor genes on 13q, other than Rb and BRCA2, may be involved in the development of NPC.

Pyridinylimidazole compound SB 203580 inhibits the activity but not the activation of p38 mitogen-activated protein kinase

p38 MAPK is a Ser/Thr protein kinase activated by various inflammatory cytokines and a variety of stress stimuli. It is involved in many physiological processes, including the production of inflammatory cytokines. We have previously reported the design and synthesis of a series of pyridinylimidazole compounds that are selective inhibitors of p38 MAPK. These compounds, exemplified by SB 203580, are exceptionally effective in cell-based assays, including the inhibition of inflammatory cytokine production. SB 203580 is widely used as a tool to dissect the role of p38 MAPK in various physiological processes. It has previously been established that SB 203580 acts primarily to block the catalytic activity of p38 MAPK. However, it has been suggested that in cells, the compounds could also inhibit p38 MAPK activation by virtue of their ability to bind to the inactive enzyme. We undertook careful studies to definitively demonstrate that treatment with SB 203580 had no effect on Thr(180) and Tyr(182) phosphorylation, and hence activation of p38 in vivo. SB 203580, however, potently inhibited the activity of p38 MAPK as demonstrated by the inhibition of the activation of MAPKAP K2, a specific physiological substrate of p38 MAPK. This was observed regardless of stimuli or cell type. Identical results were obtained when the p38 MAPK cascade was partially reconstituted in vitro. Thus, our data clearly indicate that SB 203580 specifically inhibits the activity of p38 MAPK but not its activation by upstream MAPKK.