A degeneration-based hypothesis for interpreting fibrillar changes in the osteoarthritic cartilage matrix

The collagen fibrillar architectures in the general matrix of cartilage slices removed from both normal and osteoarthritic femoral heads were examined by both differential interference light microscopy and scanning electron microscopy. Whereas the normal general matrix contained a finely differentiated pseudo-random weave of fibrils developed from an interconnected array of radial elements, the osteoarthritic general matrix was characterised by the presence of structurally distinct regions consisting of strongly aligned radial bundles of fibrils and associated intense tangles or 'knotted' features. Simple structural models were developed to explore possible transformation structures based on two different types of interconnectivity in the three-dimensional fibrillar network. These models support the hypothesis that the distinctive ultrastructural features of the osteoarthritic general matrix can develop as a consequence of largely passive degradative changes occurring in the fibrillar weave originally present in the normal matrix. This could, in principle, occur independently of any new structure that might develop as a consequence of any upregulation of collagen associated with the osteoarthritic process.

Hepatocyte nuclear factors-1alpha, -1beta, and -3beta expressed in the gonad of tilapia (Oreochromis mossambicus)

Hepatocyte nuclear factors (HNFs) are upstream regulators of many liver-specific genes and are involved in many cellular functions in the body, but their existence, expression, and function in gonads are still poorly understood. Here we report on the first cloning of partial cDNAs of HNF-1alpha and -1beta and full HNF-3beta cDNA from a tilapia (Oreochromis mossambicus) liver cDNA library. The deduced amino acid sequence of tilapia HNF-3beta has a 90 to 96% identity with those of other fishes (dwarf gourami, medaka, and zebrafish), 74% with mammals (human, rat, and mouse), and 82% with Xenopus. RT-PCR detected IGF-I and -II and HNF-1alpha, -1beta, and -3beta in both liver and gonads and the identity of the PCR fragments was confirmed by PCR hybridization. Immunoprecipitation and Western blotting also detected all three HNF proteins in both liver and gonads. Expression of HNFs in the gonads of the tilapia suggests that multi-HNFs may form a cascade to regulate gonadal physiology in the bony fish.

Environmentally induced reversible conformational switching in the yeast cell adhesion protein alpha-agglutinin

The yeast cell adhesion protein alpha-agglutinin is expressed on the surface of a free-living organism and is subjected to a variety of environmental conditions. Circular dichroism (CD) spectroscopy shows that the binding region of alpha-agglutinin has a beta-sheet-rich structure, with only approximately 2% alpha-helix under native conditions (15-40 degrees C at pH 5.5). This region is predicted to fold into three immunoglobulin-like domains, and models are consistent with the CD spectra as well as with peptide mapping and site-specific mutagenesis. However, secondary structure prediction algorithms show that segments comprising approximately 17% of the residues have high alpha-helical and low beta-sheet potential. Two model peptides of such segments had helical tendencies, and one of these peptides showed pH-dependent conformational switching. Similarly, CD spectroscopy of the binding region of alpha-agglutinin showed reversible conversion from beta-rich to mixed alpha/beta structure at elevated temperatures or when the pH was changed. The reversibility of these changes implied that there is a small energy difference between the all-beta and the alpha/beta states. Similar changes followed cleavage of peptide or disulfide bonds. Together, these observations imply that short sequences of high helical propensity are constrained to a beta-rich state by covalent and local charge interactions under native conditions, but form helices under non-native conditions.

Rubella virus DI RNAs and replicons: requirement for nonstructural proteins acting in cis for amplification by helper virus

A rubella virus (RUB) replicon was constructed by replacing the 3' proximal structural protein ORF (SP-ORF) in Robo402, a RUB infectious cDNA clone, with a reporter gene, green fluorescent protein (GFP). This replicon, RUBrep/GFP, mimics naturally occurring RUB defective-interfering (DI) RNAs generated during serial undiluted passage that maintain the 5' proximal nonstructural protein ORF (NS-ORF) but contain deletions in the SP-ORF. Following transfection of Vero cells with in vitro RNA transcripts from RUBrep/GFP, replicon replication occurred and the replicon was amplified and spread to other cells in the presence of standard helper virus. GFP expression was a much more sensitive indicator of replicon replication than was Northern analysis to detect replicon-specific RNAs. Most of a series of RUBrep/GFP constructs with deletions in the NS-ORF not only were incapable of self-replication, but were not amplified by standard helper virus. The only exception was a construct with an in-frame deletion between two NotI sites that removed nucleotides 1685-2192 of the genome; this construct did not express GFP by itself, but did express GFP in the presence of standard helper RUB and was spread to other cells. Thus, with the exception of this region, the NS-ORF is required in cis for amplification of RUB replicons by standard helper virus, explaining the selection of DI RNAs that maintain the NS-ORF. Surprisingly, when the NotI deletion was introduced into Robo402, a viable virus resulted that replicated only threefold less efficiently than did Robo402 virus. Thus, the NotI region of the NS-ORF is not necessary for virus replication. This deletion covers a region of the NS-ORF without predicted function, which therefore may function as a spacer or hinge between functional domains. Nevertheless, it was an unexpected finding that a small virus such as RUB could dispense with approximately 10% of its genome.

Characteristics of a disease of Sphagnum fuscum caused by Scleroconidioma sphagnicola

Scleroconidioma sphagnicola Tsuneda, Currah & Thormann, a dematiaceous hyphomycetous fungus, was found to cause a disease of Sphagnum fuscum (Schimp.) Klinggr. Hyphae of S. sphagnicola penetrated into chlorophyllose cells of host leaves and caused degeneration of chloroplasts, resulting in chlorosis of the infected leaves. Parasite hyphae often grew inside the host cell wall, and cavities were created around the hyphae. The invaded cell wall of Sp. fuscum appeared swollen and showed wavy deformation. In advanced stages of disease development, infected leaf chlorophyllose cells and stem cortical cells were necrotic and the entire plant became brown, shriveled, and brittle. Hyphae of S. sphagnicola began to form microsclerotia during early stages of disease development. Microsclerotia either formed conidiogenous cells on their surface or remained metabolically inactive and did not form conidiogenous cells. It was concluded that S. sphagnicola is a necrotrophic pathogen of Sp. fuscum, and its morphological and phenological features show remarkable adaptations for dispersal and colonization as a pathogen in bog habitats.Key words: moss, fungal pathogen, pathogenesis, chlorosis, necrosis, microsclerotia.

Characterization of the RcsC-->YojN-->RcsB phosphorelay signaling pathway involved in capsular synthesis in Escherichia coli

Escherichia coli and other enteric microorganisms produce an extracellular polysaccharide capsule, called colanic acid, under certain environmental conditions. This capsular synthesis is regulated by the RcsC (sensor kinase)-->YojN (phosphotransfer intermediate)-->RcsB (response regulator) phosphorelay signal transduction under certain growth conditions. Nonetheless, little is known about signals that exaggerate the Rcs-system. To gain insight into signals that activate the Rcs-system, here we searched for genes that activate the Rcs-system, provided that those on a multicopy plasmid were introduced into E. coli. We identified several such genes, namely, rcsB, rcsA, djlA, lolA, and ompG. The DjlA, LolA, and OmpG proteins are particularly interesting in that they are all located on the cell surface, where the primary sensor RcsC histidine-kinase is localized. Implications of these findings are discussed with special reference to the mechanism by which RcsC perceives external signals.

Transfer function analysis of the autonomic response to respiratory activity during random interval breathing

We report a new method for the noninvasive characterization of the frequency response of the autonomic nervous system (ANS) in mediating fluctuations in heart rate (HR). The approach entails computation of the transfer function magnitude and phase between instantaneous lung volume and HR. Broad band fluctuations in lung volume were initiated when subjects breathed on cue to a sequence of beeps spaced randomly in time. We studied 10 subjects in both supine and standing positions. The transfer function, averaged among all the subjects, showed systematic differences between the two postures, reflecting the differing frequency responses of the sympathetic and parasympathetic divisions of the ANS.

Helicobacter pylori infection in recurrent abdominal pain in children--a prospective study

A total of 40 children was recruited to assess the role of Helicobacter pylori infection in children with recurrent abdominal pain syndrome. Among 40 children, seven (17.5%) cases were confirmed to have H. pylori infection. All H. pylori-positive patients had active chronic gastritis histologic findings (p < 0.0001); however, the majority of the H. pylori-negative patients had minimal to mild gastritis histologic findings (p = 0.001). Grossly, chronic gastritis picture was present in all children infected with H. pylori and antral nodular gastropathy present in 43%. 71% of H. pylori-positive patients had elevated anti-H. pylori IgG titer; however, 15% in H. pylori-negative patients (p = 0.006). Serum H. pylori assay had a sensitivity of 71% and specificity of 85%; however, sensitivity and specificity of rapid urease test were 86% and 100% respectively. Antral nodularity is a specific, peculiar endoscopic finding of children infected with H. pylori (p = 0.004). Although the present study suggests that H. pylori-related chronic gastritis may play an etiological role in a subgroup of children with RAP syndrome, but the routine screening of H. pylori infection in children with RAP is not recommended, since no compelling data support the significant association between H. pylori infection and RAP syndrome.

Experimental and clinic-opathologic study on the relationship between transcription factor Egr-1 and esophageal carcinoma

AIM: To observe the growth suppression effect of exogenous introduction of early growth response gene-1 (Egr-1 gene) on esophageal carcinoma tissue as well as on esophageal carcinoma cell line Eca109 and to explore the potential application of Egr-1 gene in gene therapy of tumor.

METHODS: Eukaryotic expression vector of PCMV-Egr-1 plasmid was introduced into Eca109 cell line which expressed no Egr-1 protein originally with lipofectamine transfection method. The introduction and expression of PCMV-Egr-1 plasmid into Eca109 cell line was confirmed by G418 selection culture, PCR amplification of neogene contained in the vector, Western blot analysis and immunocytochemical analysis. The cell growth curve, soft agar colony formation rate and tumorigenicity in SCID mice were examined to demonstrate the growth suppression effect of exogenous Egr-1 gene on Eca109 cell line. The Egr-1 mRNA and Egr-1 protein were also detected in 50 surgical specimens of esophageal carcinoma by in situ hybridization and immunohistochemistry.

RESULTS: Exogenous Egr-1 gene was introduced successfully into Eca109 cell line and expressed Egr-1 protein stably. The transfected Eca109 cell line grew more slowly than control Eca109 as shown by cell growth curves, the soft agar colony formation rate (4.0% vs 6.9%, P < 0.01) and the average growth rate of tumor in SCID mice (35.5 ± 7.6 vs 65.8 ± 7.6, P < 0.05). The expression level of Egr-1 mRNA and protein significantly increased in dysplastic epithelia adjacent to cancer rather than in cancer tissues (65.8% vs 20.0% by ISH and 57.9% vs 14.0% by IHC, P < 0.01).

CONCLUSION: Exogenous Egr-1 gene shows the strong effect of growth inhibition in Eca109 cell line. Egr-1 in the cancer tissue shows down-regulated expression that supports the inhibited function of Egr-1 in cancer growth and suggests Egr-1 may have an important role in gene therapy of esophageal carcinoma.

Thyroidectomy or radioiodine? The value of ultrasonography and cytology in the assessment of nodular lesions in Graves' hyperthyroidism

Although diffuse toxic goiter is a classical feature of Graves' disease (GD) nodular goiters are occasionally found in some patients. The aim of the present study was to investigate the ultrasonographic and corresponding cytological manifestations in GD patients with nodular lesions to decide on a therapeutic strategy. Twenty-seven consecutive GD patients with nodular goiter were included in this study (21 women and six men, mean age 41.2 years, range 22-77 years). All underwent thyroid ultrasonography and fine-needle aspiration cytology. Of the 27 patients eight underwent surgical intervention because papillary thyroid carcinoma or follicular neoplasm was diagnosed by cytology; five of these were shown to have papillary thyroid carcinomas. Ultrasonography revealed the malignant nodules to be hypoechogenic, heterogeneous, and with ill-defined margins in four of these five thyroid cancers, whereas the remaining sonogram showed a cystic change and cauliflower-like tumor formation with microcalcification. The volume and maximal diameter of cancerous nodules were significantly larger than those of benign nodules. In conclusion our results reveal that ultrasonography and fine-needle aspiration cytology are reliable and quick methods for diagnosing nodular goiters in GD patients. If thyroid neoplasms are found ablative therapy with thyroidectomy is indicated instead of radioactive iodine.

Nonlinear transports and microvortex excitations in sheared quasi-two-dimensional dust Coulomb liquids

The microscopic spatiotemporal response of a quasi-two-dimensional dust Coulomb liquid to the shear induced by a cw laser is investigated through optical microscopy. The dust Coulomb liquid consists of many micrometer sized dust particles charged and suspended in a low pressure rf discharge background. Assisted by thermal fluctuations, the laser forcing enhances the cascaded generation of irregular vortices through reducing caging barriers for collective hopping. The vortex mixing leads to the mean velocity field with a simple structure that has a strong shear along the edge of the narrow laser beam. It also promotes the anomalous transverse diffusion with decaying strength from the line source. The viscosity and diffusion coefficient both show nonlinear dependence on the laser power under the interplay among the above nonlinear excitation and relaxation processes.

Increased microvessel density in malignant and borderline mammary phyllodes tumours

AIMS

Tumour vascularity is considered a prognostic indicator in breast carcinoma, but its utility in mammary phyllodes tumour has not been explored. The authors report the correlation between intratumoral microvessel density and the histological grade of phyllodes tumour.

METHODS AND RESULTS

Forty cases of phyllodes tumour were reviewed for stromal cellularity, overgrowth, cytological pleomorphism, mitotic count and margin pattern. Using established criteria, these were diagnosed as benign (n=28), borderline (n=10) and malignant (n=2). Microvessel density was counted on CD31-stained slides as the number of vessels per high power field. For benign phyllodes tumour, the range was 7-26.2 (mean 13.1); for borderline phyllodes tumour the range was 17.2-32.5 (mean 22.4); for malignant phyllodes tumour the range was 25.9-33.3 (mean 29.6). The difference between the benign and borderline groups was significant (P < 0.0001) but that between the borderline and malignant groups was not, due to the small number of malignant cases.

CONCLUSIONS

There is a significant difference in stromal microvessel density between benign and borderline phyllodes tumour. Although the small number of cases of malignant phyllodes tumour limits further interpretation, we believe that microvessel density can be used as an additional objective histological parameter in the evaluation of phyllodes tumour.

Bayesian semiparametric models for survival data with a cure fraction

We propose methods for Bayesian inference for a new class of semiparametric survival models with a cure fraction. Specifically, we propose a semiparametric cure rate model with a smoothing parameter that controls the degree of parametricity in the right tail of the survival distribution. We show that such a parameter is crucial for these kinds of models and can have an impact on the posterior estimates. Several novel properties of the proposed model are derived. In addition, we propose a class of improper noninformative priors based on this model and examine the properties of the implied posterior. Also, a class of informative priors based on historical data is proposed and its theoretical properties are investigated. A case study involving a melanoma clinical trial is discussed in detail to demonstrate the proposed methodology.

The characterization of prepro-Insulin-like growth factor-1 Ea-2 expression and Insulin-like growth factor-1 genes (devoid 81 bp) in the zebrafish ( Danio rerio )

In this study, we cloned zebrafish (Danio rerio) IGF-1 cDNA and gene from zebrafish brain cDNA library and adult zebrafish genomic library, respectively. Based on two cDNAs sequence with different length of 5'- and 3'-untranslated region (5UTR and 3UTR) and one nucleotide difference at glutamine (A9, CAG) of A domain represented at IGF-1 sequence. One of zebrafish IGF-1 genes named as IGF-1a gene. The zebrafish IGF-1a gene spanned approximately 15 kb and is divided into five exons. The results of IGF-1 cDNA and genomic Southern blotting, all indicated that the zebrafish have more than one IGF-1 gene. The genomic organization of zebrafish IGF-1a gene in an exon is devoid of 81 bp segment which is located at 3' end of exon 3 encoded 27 amino acid of E domain. The segment of 27 amino acid exists in known teleost IGF-1 genes but is absent in zebrafish IGF-1 gene. The E domain of zebrafish IGF-1 Ea-2 is encoded by 3' end of exon 3 (16 amino acid), full of exon 4 (12 amino acid) and exon 5 (19 amino acid). The sequence data revealed the zebrafish IGF-1a gene encoded IGF-1a Ea-2 mRNA. In combination RT-PCR with Southern blotting, zebrafish IGF-1 genes abundantly expressed IGF-1 Ea-2 mRNA in all tested adult tissues and developmental stages of embryo. The IGF-1 Ea-2 mRNA was first detected during embryo development from blastula stage to hatching, during yolk absorption and at feeding. All these findings suggest that the expression of pro-IGF-1 Ea-2 is not controlled by alternative splicing but alternative gene usage in the zebrafish.

A prospective, randomized trial of butyl cyanoacrylate injection versus band ligation in the management of bleeding gastric varices

Gastric variceal bleeding is a catastrophic event. Both cyanoacrylate injection and banding ligation have been proven to be effective in the management of bleeding gastric varices. This study was performed to compare the efficacy and complications of both the modalities. Cirrhotic patients with a history of gastric variceal bleeding were randomized to 2 groups. The group receiving endoscopic obturation (group A) comprised 31 patients and the group receiving band ligation (group B) comprised 29 patients. Butyl cyanoacrylate and pneumatic-driven ligator were applied, respectively. Treatment was repeated regularly until obliteration of gastric varices. Active bleeding occurred in 15 patients in group A and 11 patients in group B. Initial hemostatic rate (defined as no bleeding for 72 hours after treatment) was 87% in group A and 45% in group B (P = .03). The sessions required to achieve variceal obliteration and obliteration rates were similar in both the groups. However, rebleeding rates were significantly higher in group B (54%) than group A (31%) (P = .0005). Treatment-induced ulcer bleeding occurred in 2 patients (7%) in group A and 8 patients (28%) in group B (P = .03). The amount of blood transfusions required were also higher in group B than group A (4.2 +/- 1.3 vs. 2.6 +/- 0.9 units, respectively) (P < .01). Nine patients of group A and 14 patients of group B died (P = .05). In conclusion, endoscopic obturation using cyanoacrylate proved more effective and safer than band ligation in the management of bleeding gastric varices.

Paclitaxel, cisplatin, and concurrent radiation for esophageal cancer

Paclitaxel is an active agent for adenocarcinomas and squamous cell carcinomas of the esophagus and is a radiation sensitizer. We sought to investigate the toxicity and complete response rate of paclitaxel, cisplatin, and concurrent radiation for esophageal cancer. Forty-one patients with esophageal cancer were studied, 29 with adenocarcinomas and 12 with squamous cell cancers. Twelve patients had tumor extension into the proximal stomach and/or abdominal adenopathy. Patients received paclitaxel 60 mg/m2 by 3-hour intravenous (i.v.) infusion, and cisplatin 25 mg/m2 weekly on days 1, 8, 15, and 22. Radiation was administered concurrently to a total dose of 39.60 Gy, in 1.80 Gy fractions, for 22 treatments. Patients with medical or surgical contraindications to esophagectomy received 2 additional weeks of paclitaxel with a radiation boost to 50.4 Gy. Neutropenia was the most common grade 3/4 toxicity occurring in 10 patients (24%). Only 2 patients (5%) had grade 4 esophagitis requiring parenteral nutrition. Twelve patients (29%) obtained a complete response. The 2-year progression-free and overall survival rates were 40% and 42%, respectively. Esophagitis was less severe than expected and prophylactic enteral feeding tubes were not necessary. Additional effective systemic treatments are needed to reduce the development of distant metastases.

Effect of phosphate on stability of pyridoxal in the presence of lysine

The stability of the biologically active compound vitamin B(6) in aqueous solution was investigated. Schiff base formation is the major reaction between the epsilon-amino group of lysine and the aldehyde group of both pyridoxal and pyridoxal phosphate. Model systems composed of equal molar concentrations of lysine with either pyridoxal or pyridoxal phosphate were used to study the effect of proton transfer on Schiff base formation. Pyridoxylidenelysine was found to be the major product in both lysine/pyridoxal and lysine/pyridoxal phosphate systems. Quantitation of residual pyridoxal and pyridoxal phosphate was conducted using an HPLC to evaluate the degradation of pyridoxal and pyridoxal phosphate. The results indicate both the free phosphate ion in the buffer system and the bound phosphate on pyridoxal phosphate can enhance the formation of the Schiff base. The phosphate group serves as both proton donor and acceptor, which catalyzes the Schiff base formation. The aldehyde group on pyridoxal phosphate was found to be much more reactive than that on pyridoxal. The bound phosphate group on pyridoxal phosphate, with proton donating and accepting groups in close proximity, can simultaneously donate and accept protons, thus enhancing Schiff base formation between the aldehyde group and the epsilon-amino group. The deterioration rate of pyridoxal phosphate was faster than that of pyridoxal in an aqueous system.

Maximum likelihood methods for cure rate models with missing covariates

We propose maximum likelihood methods for parameter estimation for a novel class of semiparametric survival models with a cure fraction, in which the covariates are allowed to be missing. We allow the covariates to be either categorical or continuous and specify a parametric distribution for the covariates that is written as a sequence of one-dimensional conditional distributions. We propose a novel EM algorithm for maximum likelihood estimation and derive standard errors by using Louis's formula (Louis, 1982, Journal of the Royal Statistical Society, Series B 44, 226-233). Computational techniques using the Monte Carlo EM algorithm are discussed and implemented. A real data set involving a melanoma cancer clinical trial is examined in detail to demonstrate the methodology.

Nucleic acid transport in plant-microbe interactions: the molecules that walk through the walls

Many microbes "genetically invade" plants by introducing DNA or RNA molecules into the host cells. For example, plant viruses transport their genomes between host cells, whereas Agrobacterium spp. transfer T-DNA to the cell nucleus and integrate it into the plant DNA. During these events, the transported nucleic acids must negotiate several barriers, such as plant cell walls, plasma membranes, and nuclear envelopes. This review describes the microbial and host proteins that participate in cell-to-cell transport and nuclear import of nucleic acids during infection by plant viruses and Agrobacterium spp. Possible molecular mechanisms by which these transport processes occur are discussed.

Perineural invasion as a predictor of biochemical outcome following radical prostatectomy for select men with clinically localized prostate cancer

PURPOSE

The presence of perineural invasion on the prostate needle biopsy specimen has been suggested to be an independent predictor of prostate specific antigen (PSA) outcome following radical prostatectomy. We evaluated the clinical use of perineural invasion at biopsy for predicting time to PSA failure following radical prostatectomy after controlling for established prognostic factors.

MATERIALS AND METHODS

A prospective evaluation using a Cox regression multivariate analysis of 750 men with clinically localized or PSA detected prostate cancer was performed to evaluate the ability of PSA, biopsy Gleason score, perineural invasion on the needle biopsy specimen and the percent of positive prostate biopsies to predict PSA outcome following radical prostatectomy.

RESULTS

Multivariate analysis demonstrated that the presence of perineural invasion on the needle biopsy specimen provided additional information regarding 5-year PSA outcome (82% versus 95%, p = 0.04) for patients who were in the low risk group. This difference in PSA outcome could be explained by higher rates of positive surgical margins (25% versus 17%, p = 0.07). Patients whose prostate needle biopsy contained perineural invasion and who had the corresponding neurovascular bundle resected had a significantly lower positive margin rate (11% versus 100%, p = 0.001) compared to those who had the neurovascular bundle spared. The presence of perineural invasion on biopsy was not a significant predictor of PSA outcome following radical prostatectomy for patients in the intermediate or high risk group.

CONCLUSIONS

Resection of the neurovascular bundle on the side corresponding to location of perineural invasion on the biopsy may decrease the positive surgical margin rate and improve outcome for low risk patients.

Morphometric analysis of argyrophilic nucleolar organizer regions (AgNORs) in nasopharyngeal carcinoma

BACKGROUND

Nucleolar organizer regions (NORs), which are loops of DNA containing ribosomal RNA genes, have been shown to correlate with cell proliferation and malignant transformation. Conventional eyeball measurement of silver staining NORs (AgNORs) is time-consuming and subject to error. The diagnostic value of AgNOR area in nasopharyngeal carcinoma (NPC) by computer-assisted morphometric analysis is evaluated.

METHODS

Silver-staining of NORs was applied to 23 paraffin sections of NPC containing both normal squamous epithelial and malignant cells. Various parameters of the AgNORs of these two cell types were analyzed by a computer-assisted image analysis system and then compared.

RESULTS

The mean AgNOR area, AgNOR/nuclear area ratio, and AgNOR area/count ratio of malignant tumors were statistically significantly higher than those for the normal epithelium. There was no significant difference in the AgNOR counts between the two cell types.

CONCLUSIONS

Computer-assisted morphometric analysis of AgNOR is an objective and reliable assessment method applicable to paraffin sections of NPC. The AgNOR area and its derivatives may aid in the diagnosis of NPC.

Efficient and specific initiation of subgenomic RNA synthesis by cucumber mosaic virus replicase in vitro requires an upstream RNA stem-loop

We defined the minimal core promoter sequences responsible for efficient and accurate initiation of cucumber mosaic virus (CMV) subgenomic RNA4. The necessary sequence maps to positions -28 to +15 relative to the initiation cytidylate used to initiate RNA synthesis in vivo. Positions -28 to -5 contain a 9-bp stem and a 6-nucleotide purine-rich loop. Considerable changes in the stem and the loop are tolerated for RNA synthesis, including replacement with a different stem-loop. In a template competition assay, the stem-loop and the initiation cytidylate are sufficient to interact with the CMV replicase. Thus, the mechanism of core promoter recognition by the CMV replicase appears to be less specific in comparison to the minimal subgenomic core promoter of the closely related brome mosaic virus.

Pathologic findings and prostate specific antigen outcome after radical prostatectomy for patients diagnosed on the basis of a single microscopic focus of prostate carcinoma with a gleason score </= 7

BACKGROUND

Whether patients who are diagnosed on the basis of a single microscopic focus of prostate carcinoma with a Gleason score </= 7 (micro PC) have potentially life-threatening disease if they are not treated is unknown.

METHODS

Pathologic findings and prostate specific antigen (PSA) outcome after radical prostatectomy (RP) for men who were diagnosed with micro PC were determined. Of 917 patients who were managed with RP during 1989-1999 at the Brigham and Women's Hospital, 66 patients (7%) were diagnosed on the basis of micro PC. Pathologic stage, tumor grade, tumor volume, margin status, and PSA outcome were investigated and are reported. Estimates of PSA outcome were calculated using the actuarial method of Kaplan and Meier. Pairwise comparisons were made using the log rank test.

RESULTS

The finding of micro PC at biopsy was associated with macroscopic disease (involving at least half of a single lobe) in 92% of the patients in this series. Although these men had favorable pathologic findings (94% had organ confined disease, 89% had negative tumor margins, and 79% had a prostatectomy Gleason score </= 6), approximately 10% of the patients failed biochemically within 5 years after RP.

CONCLUSIONS

The finding of micro PC at biopsy should not be used as a surrogate for clinically insignificant disease.

Peroxisome proliferator-activated receptor gamma 2 Pro12Ala gene variant is strongly associated with larger body mass in the Taiwanese

The peroxisome proliferator-activated receptor gamma 2 (PPARgamma2) has been studied extensively because of its putative role in adipocyte differentiation and insulin sensitivity. The association of the Pro12Ala and Pro115Gln PPARgamma2 gene variants with type 2 diabetes mellitus, the body mass index (BMI), and other diabetes-related phenotypes was examined in the Taiwanese population. Genotypes were determined by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis. Allele frequencies were compared between 280 subjects with type 2 diabetes mellitus and 310 subjects without diabetes using the chi-square test. Continuous phenotype analysis was performed by multiple logistic regression adjusting for age and BMI where appropriate. There was no significant association between the Pro12Ala gene variant and type 2 diabetes; the frequency of the Ala12 allele was 0.03 in type 2 diabetics and 0.04 in nondiabetics (P = .40). The Gln115 allele was not detected in any of the cases or controls. In multiple linear regression analysis of all cases and controls combined adjusted for age, sex, and diabetic status, carriers of the Ala12 allele had a mean BMI of 25.9+/-0.5 kg/m2 (mean +/- SE), compared with 24.2+/-0.1 kg/m2 in Pro12 homozygotes (P < .001). In addition, carriers of the Ala12 allele have a 2.9 times (95% confidence interval [CI], 1.5 to 5.5) higher odds of having a BMI of at least 25 kg/m2. These results suggest that in the Taiwanese, the Pro12Ala PPARgamma2 gene variant may contribute to fat accumulation and a higher BMI independent of type 2 diabetes. These results need to be confirmed in future studies, as a linkage disequilibrium of this variant with other mutations cannot be ruled out.

Utilizing predictions of early prostate-specific antigen failure to optimize patient selection for adjuvant systemic therapy trials

PURPOSE

Prostate-specific antigen (PSA) failure within 2 years after radical prostatectomy (RP) has been shown to be a clinically significant predictor of distant failure. This study was performed to estimate 2-year PSA failure rates on the basis of readily available clinical and pathologic factors to identify patients for whom effective adjuvant systemic therapy is needed.

PATIENTS AND METHODS

A Cox regression multivariable analysis was used to determine whether the percentage of positive prostate biopsies, PSA level, and the pathologic findings at RP in 1,728 men provided clinically relevant information about PSA outcome after RP. A bootstrapping technique with 2,000 replications was used to provide 95% confidence intervals for the predicted 2-year PSA failure rates, which were determined on the basis of the independent clinical and pathologic predictors of PSA outcome.

RESULTS

The independent predictors of time to PSA failure included a percentage of positive prostate biopsies of greater than 34% (P: < or =.009), PSA level greater than 10 ng/mL (P: < or =.01), seminal vesicle invasion (P: =. 02), prostatectomy Gleason score of 8 to 10 (P: =.04), and positive surgical margins (P: =.0001). Predictions of 2-year PSA failure rates and bootstrap estimates of the 95% confidence intervals were arranged in a tabular format, stratified by independent clinical and pathologic predictors of PSA outcome.

CONCLUSION

Patients who are most likely to benefit from effective adjuvant systemic therapy after RP can be identified using readily available clinical and pathologic data.

Regulation of plasmodesmal transport by phosphorylation of tobacco mosaic virus cell-to-cell movement protein

Cell-to-cell spread of tobacco mosaic virus (TMV) through plant intercellular connections, the plasmodesmata, is mediated by a specialized viral movement protein (MP). In vivo studies using transgenic tobacco plants showed that MP is phosphorylated at its C-terminus at amino acid residues Ser258, Thr261 and Ser265. When MP phosphorylation was mimicked by negatively charged amino acid substitutions, MP lost its ability to gate plasmodesmata. This effect on MP-plasmodesmata interactions was specific because other activities of MP, such as RNA binding and interaction with pectin methylesterases, were not affected. Furthermore, TMV encoding the MP mutant mimicking phosphorylation was unable to spread from cell to cell in inoculated tobacco plants. The regulatory effect of MP phosphorylation on plasmodesmal permeability was host dependent, occurring in tobacco but not in a more promiscuous Nicotiana benthamiana host. Thus, phosphorylation may represent a regulatory mechanism for controlling the TMV MP-plasmodesmata interactions in a host-dependent fashion.

Bayesian predictive inference for time series count data

Correlated count data arise often in practice, especially in repeated measures situations or instances in which observations are collected over time. In this paper, we consider a parametric model for a time series of counts by constructing a likelihood-based version of a model similar to that of Zeger (1988, Biometrika 75, 621-629). The model has the advantage of incorporating both overdispersion and autocorrelation. We consider a Bayesian approach and propose a class of informative prior distributions for the model parameters that are useful for prediction. The prior specification is motivated from the notion of the existence of data from similar previous studies, called historical data, which is then quantified into a prior distribution for the current study. We derive the Bayesian predictive distribution and use a Bayesian criterion, called the predictive L measure, for assessing the predictions for a given time series model. The distribution of the predictive L measure is also derived, which will enable us to compare the predictive ability for each model under consideration. Our methodology is motivated by a real data set involving yearly pollen counts, which is examined in some detail.

Endoscopic variceal ligation plus nadolol and sucralfate compared with ligation alone for the prevention of variceal rebleeding: a prospective, randomized trial

Both beta-blockers and endoscopic variceal ligation (EVL) have proven to be valuable alternatives to sclerotherapy in the prevention of variceal rebleeding. Sucralfate is a mucosal protector. The effects of combinations of beta-blocker, band ligation, and sucralfate (triple therapy) remain unknown. A total of 122 patients with a history of esophageal variceal bleeding were randomized to receive EVL only (group A, 62 patients) or triple therapy (group B, 60 patients). The procedure for the triple therapy included ligation with the addition of sucralfate granules until variceal obliteration. In addition, nadolol was administered during the course of the study or until death. After a median follow-up of 21 months, recurrent upper gastrointestinal bleeding developed in 29 patients (47%) in group A and 14 patients (23%) in group B (P =.005). Recurrent bleeding from esophagogastric varices occurred in 18 patients in group A and 7 patients in group B (P =.001). Twenty-one patients in group A (50%) and 12 patients (26%) in group B experienced variceal recurrence after variceal obliteration (P <.05). Treatment failure occurred in 11 patients (18%) in group A and in 4 patients (7%) in group B (P =.05). Twenty patients from group A and 10 patients from group B died (P =.08); 9 and 4 of these deaths, respectively, were attributed to variceal hemorrhage (P =.26). The combination of ligation, nadolol, and sucralfate (triple therapy) proved more effective than banding ligation alone in terms of prevention of variceal recurrence and upper gastrointestinal rebleeding as well as variceal rebleeding.

Analysis of physician ability in the measurement of pulsus paradoxus by sphygmomanometry

CONTEXT

Measurement of pulsus paradoxus (PP) is one of several measures previously advocated in the National Heart, Lung, and Blood Institute asthma management guidelines: a pulsus of > 12 mm Hg warranted hospital admission. It is one of only a few measures that is not effort dependent and therefore important in the evaluation of patients with asthma.

OBJECTIVE

Determination of physician accuracy in measuring PP.

DESIGN

A model of induced PP in a trained healthy subject without respiratory disease was constructed with a fixed inspiratory resistance with measurement of inspiratory air pressure and beat-to-beat BP noninvasively.

SETTING

Laboratory.

PARTICIPANTS

Attending physicians from emergency medicine and critical care disciplines who served as consecutive examiners of the trained reference subject generating known PP.

INTERVENTIONS

A total of 19 attending physicians were assessed for ability in measuring PP by sphygmomanometry and by palpation. The reference subject generated 4 degrees of PP sequentially, with each examiner blinded to the value of negative inspiratory pressure and PP. Examiners first assessed PP qualitatively by palpation, followed by its measurement within 2 min.

MAIN OUTCOME MEASURE

Proximity of physician-measured PP (PPm) to true PP (PPt).

RESULTS

At inspiratory pressures of - 10, - 15, - 20, and - 25 mm Hg, PPt was 13.7, 16.2, 19.1, and 20.7 mm Hg, respectively (F = 14.8, p < 0. 0001; analysis of variance [ANOVA]). At the same pressures, PPm was 13.1, 17.5, 17.7, and 18.0 mm Hg (p > 0.10; ANOVA). Linear regression of PPm against PPt for each examiner revealed a slope (SE) of 0.53 (0.23), and not a 1:1 relationship.

CONCLUSIONS

Past and present guidelines do not account for the challenges in measuring PP, especially in tachypneic patients. Sphygmomanometric determination of PP should be augmented by new aids developed through technological innovation.

A CD2-based model of yeast alpha-agglutinin elucidates solution properties and binding characteristics

We have previously shown that the Saccharomyces cerevisiae cell adhesion protein alpha-agglutinin has sequence characteristics of immunoglobulin-like proteins and have successfully modeled residues 200-325, based on the structure of immunoglobulin variable-type domains. Alignments matching residues 20-200 of alpha-agglutinin with domains I and II of members of the CD2/CD4 subfamily of the immunoglobulin superfamily showed > 80% conservation of key residues despite low sequence similarity overall. Three-dimensional models of two alpha-agglutinin domains constructed on the basis of these alignments were shown to conform to peptide mapping data and biophysical properties of alpha-agglutinin. In addition, the residue volume and surface accessibility characteristics of these models resembled those of the well-packed structures of related proteins. Residue-by-residue analysis showed that packing and accessibility anomalies were largely confined to glycosylated and protease-susceptible loop regions of the domains. Surface accessibility of hydrophobic residues was typical of proteins with extensive domain interactions, a finding compatible with the hydrodynamic properties of alpha -agglutinin and the hydrophobic nature of binding to its peptide ligand alpha-agglutinin. The procedures used to align the alpha-agglutinin sequence and test the quality of the model may be applicable to other proteins, especially those that resist crystallization because of extensive glycosylation.

Evaluation of stroke patients with the extended activities of daily living scale in Taiwan

PURPOSE

This study examined the construct validity of the Nottingham Extended Activities of Daily Living scale (EADL) in stroke patients in Taiwan.

METHODS

The EADL and the Barthel Index were administered via telephone interview. Minor revisions were made for the EADL to reflect cultural differences and the recommendations of two previous studies on the use of EADL. One hundred and fifty three stroke patients from the community participated in the study.

RESULTS

Two items, 'make hot snack' and 'write letters', were deleted from the EADL because they appeared to be of little discriminative value. The results suggest that a changed hierarchical order was present among the domestic and leisure subscales. All of the subscales, then, fulfilled the Guttman scaling criteria (coefficient of reproducibility > 0.9, coefficient of scalability > 0.6). The scores of the revised EADL were significantly related to age and the Barthel Index scores (Spearman correlation coefficients = -0.41 and 0.69, respectively, p < 0.001). There was no significant difference between the overall scores of men and women (median = 10, 10, respectively, Mann-Whitney U test, p = 0.67).

CONCLUSION

These data support the validity of the EADL with minor modifications in the evaluation of the functional performance in stroke patients in Taiwan and confirm it to be a useful outcome measure in stroke research.

Histone deacetylases specifically down-regulate p53-dependent gene activation

p53, the most commonly mutated gene in cancer cells, directs cell cycle arrest or induces programmed cell death (apoptosis) in response to stress. It has been demonstrated that p53 activity is up-regulated in part by posttranslational acetylation. In agreement with these observations, here we show that mammalian histone deacetylase (HDAC)-1, -2, and -3 are all capable of down-regulating p53 function. Down-regulation of p53 activity by HDACs is HDAC dosage-dependent, requires the deacetylase activity of HDACs, and depends on the region of p53 that is acetylated by p300/CREB-binding protein (CBP). These results suggest that interactions of p53 and HDACs likely result in p53 deacetylation, thereby reducing its transcriptional activity. In support of this idea, GST pull-down and immunoprecipitation assays show that p53 interacts with HDAC1 both in vitro and in vivo. Furthermore, a pre-acetylated p53 peptide was significantly deacetylated by immunoprecipitated wild type HDAC1 but not deacetylase mutant. Also, co-expression of HDAC1 greatly reduced the in vivo acetylation level of p53. Finally, we report that the activation potential of p53 on the BAX promoter, a natural p53-responsive system, is reduced in the presence of HDACs. Taken together, our findings indicate that deacetylation of p53 by histone deacetylases is likely to be part of the mechanisms that control the physiological activity of p53.

Reduction of cardiac volume in left-breast treatment fields by respiratory maneuvers: a CT study

PURPOSE

A previous study of healthy female volunteers suggested that deep inspiratory breath holding can reduce the cardiac volume in the treatment portals for left-breast cancer treatment. The reduction of irradiated cardiac volume may be important considering the reported late cardiac morbidity and mortality and the frequent coexistent use of potentially cardiotoxic chemotherapy in breast cancer patients. In the present study, we evaluated the heart volume in the fields and, thus, the true benefit of this respiratory maneuver in breast cancer patients undergoing CT simulation.

MATERIALS AND METHODS

Fifteen patients (median age, 53) were studied. For each patient, CT scans were performed both when the patient breathed normally (quiet respiration) and when the patient held her breath after a deep inspiration. Tangential fields were planned using the same medial, lateral, superior, and inferior borders on skin for the normal breathing and the breath-holding configurations. The cardiac and left-lung volumes within the tangential fields were calculated for both breathing configurations. Multiple scan series were performed for the breath-holding configuration to provide a more accurate delineation of the cardiac tissue and to study the reproducibility of the patient's position between different cycles of deep inspiration.

RESULTS

None of the patients had difficulty holding her breath for 20 s. The cardiac volume in the field was reduced (-86 +/- 24%; p < 0.001) when patients held their breath after a deep inspiration compared to when breathing normally. For 7 patients (47%), deep inspiration moved the heart completely out of the radiation fields. The expansion of the lung tissue due to deep inspiration also increased the absolute lung volume in the tangential fields (183 cm(3) vs 97 cm(3), p < 0.001). However, the fractional volume of the left lung in the field was essentially unchanged. For all but 1 patient, the maximum difference between the external body contours from different breath holding cycles was 5 mm and occurred at the lateral aspect of the breast. At the medial aspect, as indicated by the position of the midline marker, the variations were well within the currently accepted tolerance for patient positioning during tangential treatment.

CONCLUSIONS

Deep-inspiration breath holding substantially reduces cardiac volume in the tangential fields for left-sided breast cancer treatment. The variation between patient positions at different cycles of breath holding was found to be reasonably small. Therefore, it appears feasible to reduce cardiac radiation by treating patients with intratreatment minifractions lasting 10-15 s while patients hold their breath.

Risk factors for syncope in a community-based sample (the Framingham Heart Study)

The epidemiology of syncope has not been well described. Prior studies have examined risk factors for syncope in hospital-based or other acute or long-term care settings. To determine risk factors for syncope in a community-based sample, we performed a nested case-control study. We examined reports of syncope in Framingham Heart Study participants who underwent routine clinic visits from 1971 to 1990. For each syncope case (n = 543) 2 controls were matched for age, sex, and examination period. Mean age of subjects was 67 years (range 25 to 95); 59% were women. History of stroke or transient ischemic attack, history of myocardial infarction, high blood pressure, use of antihypertensive medication, use of other cardiac medication, smoking, alcohol intake, body mass index, systolic blood pressure, diastolic blood pressure, heart rate, atrial fibrillation, PR interval prolongation, interventricular block, and diabetes or elevated glucose level were examined as potential predictors. Using conditional logistic regression analysis, the predictors of syncope included a history of stroke or transient ischemic attack (odds ratio [OR] 2.56, 95% confidence interval [CI] 1.62 to 4.04), use of cardiac medication (OR 1.67, 95% CI 1.21 to 2. 30), and high blood pressure (OR 1.46, 95% CI 1.14 to 1.88). Lower body mass index was marginally associated with syncope (OR per 4 kg/m(2) decrement 1.10, 95% CI 0.99 to 1.22), as were increased alcohol intake (OR per 5 oz/week 1.11, 95% CI 0.99 to 1.26), and diabetes or an elevated glucose level (OR 1.29, 95% CI 0.96 to 1.75). To our knowledge, this study represents the first community-based study of risk factors for syncope.

Adherence to antiretroviral therapy among HIV-infected methadone patients: effect of ongoing illicit drug use

Methadone maintenance patients infected with human immunodeficiency virus (HIV) currently receiving antiretroviral therapy had HIV RNA testing and were surveyed regarding their adherence to their treatment regimens. Adherence was measured using self-report on four questions relating to medication use in the last day and last month and whether the patient took "drug holidays." Of the patients (N = 42), 52% were receiving two-drug antiretroviral therapy and 48% were receiving triple therapy that included a protease inhibitor. Persons on triple therapy reported higher rates of adherence on all measures and were more likely to have undetectable HIV RNA levels than persons on dual therapy (60% vs. 50%). Ongoing illicit drug injection was the only factor significantly associated (p < .05) with multiple measure nonadherence; however, it was not associated with undetectable HIV RNA level. Levels of nonadherence were comparable to estimates from other chronic diseases, but this finding has important implications for patients receiving highly active antiretroviral therapy.

Clinical utility of the percentage of positive prostate biopsies in defining biochemical outcome after radical prostatectomy for patients with clinically localized prostate cancer

PURPOSE

To determine the clinical utility of the percentage of positive prostate biopsies in predicting prostate-specific antigen (PSA) outcome after radical prostatectomy (RP) for men with PSA-detected or clinically palpable prostate cancer.

METHODS

A Cox regression multivariable analysis was used to determine whether the percentage of positive prostate biopsies provided clinically relevant information about PSA outcome after RP in 960 men while accounting for the previously established risk groups that are defined according to pretreatment PSA level, biopsy Gleason score, and the 1992 American Joint Committee on Cancer (AJCC) clinical T stage. The findings were then tested using an independent surgical database that included data for 823 men.

RESULTS

Controlling for the known prognostic factors, the percentage of positive prostate biopsies added clinically significant information (P <.0001) regarding time to PSA failure after RP. Specifically, 80% of the patients in the intermediate-risk group (1992 AJCC T2b, or biopsy Gleason 7 or PSA > 10 ng/mL and </= 20 ng/mL) could be classified into either an 11% or 86% 4-year PSA control cohort using the preoperative prostate biopsy data. These findings were validated in the intermediate-risk patients using an independent surgical data set.

CONCLUSION

The validated stratification of PSA outcome after RP using the percentage of positive prostate biopsies in intermediate-risk patients is clinically significant. This information can be used to identify men with newly diagnosed and clinically localized prostate cancer who are at high risk for early (</= 2 years) PSA failure and, therefore, may benefit from the use of adjuvant therapy.

Interaction between the tobacco mosaic virus movement protein and host cell pectin methylesterases is required for viral cell-to-cell movement

Virus-encoded movement protein (MP) mediates cell-to-cell spread of tobacco mosaic virus (TMV) through plant intercellular connections, the plasmodesmata. The molecular pathway by which TMV MP interacts with the host cell is largely unknown. To understand this process better, a cell wall-associated protein that specifically binds the viral MP was purified from tobacco leaf cell walls and identified as pectin methylesterase (PME). In addition to TMV MP, PME is recognized by MPs of turnip vein clearing virus (TVCV) and cauliflower mosaic virus (CaMV). The use of amino acid deletion mutants of TMV MP showed that its domain was necessary and sufficient for association with PME. Deletion of the PME-binding region resulted in inactivation of TMV cell-to-cell movement.

Paclitaxel and concurrent radiation for gastric cancer

PURPOSE

To determine the activity and toxicity of paclitaxel and concurrent radiation for gastric cancer.

METHODS AND MATERIALS

Twenty-seven patients were studied. Twenty-five had proximal gastric cancers, two had distal cancers. Eight had esophageal extension, 6 had celiac adenopathy, and 7 had retroperitoneal adenopathy. Patients received paclitaxel, 50 mg/m(2) by 3-hour intravenous (IV) infusion, weekly, on days 1, 8, 15, 22, and 29. Radiation was administered concurrently to a total dose of 45.0 Gy, in 1.80 Gy fractions, for 25 treatments. Patients who were medically or surgically inoperable received a sixth week of paclitaxel with a radiation boost to 50.4 Gy.

RESULTS

Esophagitis and gastritis were the most important toxicities, Grade 3 in four patients (15%), and Grade 4 in three patients (11%). Five patients (19%) had Grade 3 nausea. The overall response rate was 56%, including three patients (11%) with a complete response. The 2-year progression-free and overall survival rates were 29% and 31%, respectively.

CONCLUSION

Concurrent paclitaxel and radiation demonstrates substantial local-regional activity in gastric cancer. Future investigations combining paclitaxel and radiation with other local-regional and systemic treatments are warranted.

Modeling directed design and biological evaluation of quinazolinones as non-peptidic growth hormone secretagogues

Quinazolinone derivatives were synthesized and evaluated as non-peptidic growth hormone secretagogues. Modeling guided design of quinazolinone compound 21 led to a potency enhancement of greater than 200-fold compared to human growth hormone secretagogue affinity of a screening lead 4.

Histopathological Study of Barley Cultivars Resistant and Susceptible to Rhynchosporium secalis

ABSTRACT Differences in the penetration process by Rhynchosporium secalis were compared in resistant and susceptible barley cultivars at the seedling stage. Percent penetration and percent host cell wall alteration (HCWA) differed significantly among cultivars and isolates as revealed by light microscopy. Based on these two variables, the cultivars were statistically separated into two groups that corresponded to their disease reactions. The resistant cultivars, Johnston and CDC Guardian, showed 81.2 to 99.4% HCWA and 0.1 to 20.1% penetration at encounter sites, whereas the susceptible cultivars, Harrington, Argyle, and Manley, had 30.1 to 78.3% HCWA and 31.8 to 81.8% penetration. In the current study, cv. Leduc, which is susceptible at the seedling stage and resistant at the adult stage, showed the same percent HCWA and penetration as did susceptible cultivars. A significant negative correlation (P < 0.01) was found between percent penetration and percent HCWA for cultivars inoculated with two isolates of the pathogen. Isolate 1 was less virulent than isolate 2 with respect to percent penetration and induced significantly fewer HCWA. Scanning electron microscopy showed various shapes of fungal appressoria but no apparent difference in host reaction between resistant and susceptible cultivars. Transmission electron microscopy revealed interactions between the host and pathogen at various stages of penetration. The resistant cv. Johnston responded by producing appositions, as evidenced by a layer of compact osmiophilic material deposited on the inner side of the cell wall. Infection pegs produced by conidia were unable to penetrate the cuticle where an apposition had formed inside. When penetration occurred in the susceptible cv. Argyle, cytoplasmic aggregates and separation of the plasmalemma were visible from the host cell wall, but the layer of compact osmiophilic material was not always present. Data based on light microscopic observations suggested that HCWA may be one of the mechanisms responsible for resistance that is characterized as penetration prevention rather than as a slow rate of mycelial growth after successful penetration. HCWA occurred in response to attempted cuticle penetration, suggesting that HCWA may produce chemical barriers that help to prevent penetration.

Cell-to-cell movement of tobacco mosaic virus: enigmas and explanations

Abstract Tobacco mosaic virus (TMV) spreads between cells through plant intercellular connections, the plasmodesmata. This transport process is mediated by a specialized virus-encoded movement protein, TMV MP. Recent advances in two major aspects of TMV MP function highlight the limits of our current knowledge and promise exciting future developments. First, findings that TMV MP interacts with cytoskeletal elements and cell wall proteins suggest potential mechanisms for TMV MP targeting from the cell cytoplasm to plasmodesmal channels. Second, indications that TMV MP phosphorylation plays a regulatory role in several activities of TMV MP begin to unravel molecular pathways that control TMV cell-to-cell transport. TMV systemic movement that follows its initial cell-to-cell spread, on the other hand, may be controlled through two different pathways used for viral entry into and exit from the host plant vascular tissue.

PSA-based outcome analysis after radiation therapy for prostate cancer: a new definition of biochemical failure after intervention

OBJECTIVES

To examine pretreatment variables that influence biochemical failure, and to describe and test a new definition of prostate-specific antigen (PSA)-based biochemical failure.

METHODS

We introduce and describe a new definition of biochemical failure, which is based on quadratic fitting of the logarithm of the follow-up PSA profile curve. From a data base of 449 patients with prostate cancer treated with definitive radiation therapy, 230 patients who had at least five follow-up PSA observations were chosen for analysis. The new definition of failure was applied to this cohort, as was the conventional definition of two consecutive PSA rises. Univariate and multivariate analyses were performed using established pretreatment prognostic factors as covariates. Also, the association of both definitions of failure with clinical outcome (local recurrence and any recurrence) was examined.

RESULTS

Application of the new definition of biochemical failure resulted in smoothing of the "noise" that is inherent in using definitions based on successive PSA rises. This smoothing was verified by smaller P values for the statistically significant covariates in the univariate analysis. Furthermore, the new definition correlated better with clinical outcome, as demonstrated by the statistically significant P values on regression analysis when using the quadratic fitted nadir compared with using the observed nadir.

CONCLUSIONS

We devised a new criterion based on quadratic curve fitting for PSA-based biochemical failure. This definition is based on all available PSA information, correlates with both pretreatment factors and post-treatment clinical outcome, is relatively insensitive to noise, and allows for prediction of time of failure.

Non-ignorable missing covariates in generalized linear models

We propose a likelihood method for estimating parameters in generalized linear models with missing covariates and a non-ignorable missing data mechanism. In this paper, we focus on one missing covariate. We use a logistic model for the probability that the covariate is missing, and allow this probability to depend on the incomplete covariate. We allow the covariates, including the incomplete covariate, to be either categorical or continuous. We propose an EM algorithm in this case. For a missing categorical covariate, we derive a closed form expression for the E- and M-steps of the EM algorithm for obtaining the maximum likelihood estimates (MLEs). For a missing continuous covariate, we use a Monte Carlo version of the EM algorithm to obtain the MLEs via the Gibbs sampler. The methodology is illustrated using an example from a breast cancer clinical trial in which time to disease progression is the outcome, and the incomplete covariate is a quality of life physical well-being score taken after the start of therapy. This score may be missing because the patients are sicker, so this covariate could be non-ignorably missing.

Combination of color Doppler ultrasonography and ultrasound-guided fine-needle aspiration cytology for localization of parathyroid lesions

We examined the usefulness of color Doppler ultrasonography combined with ultrasound-guided fine-needle aspiration cytology (FNAC) for preoperative localization of parathyroid lesions in patients with hyperparathyroidism. Twenty-eight patients (19 men, 9 women; mean age, 56 years) with clinical and laboratory evidence of hyperparathyroidism underwent preoperative color Doppler ultrasonography and ultrasound-guided FNAC prior to surgery. On ultrasonography, the parathyroid lesions were anechoic or hypoechoic, located behind or at the margin of the thyroid gland, and mimicked blood vessels in some cases. On color Doppler ultrasound, parathyroid lesions showed little or no vascularity. They were easily differentiated from blood vessels, thus improving the safety of ultrasound-guided FNAC. Thirty-four (76%) of 45 surgically confirmed parathyroid lesions were detected with ultrasonography in 21 (75%) of the patients. There was no significant difference in the detection rates of lesions in the right upper, right lower, left upper, and left lower parathyroid glands. Eight (29%) patients had coexisting thyroid lesions. FNAC of the ultrasound-detected abnormalities provided preoperative confirmation that they were parathyroid lesions. In conclusion, our findings show that color Doppler ultrasonogrphy in combination with ultrasound-guided FNAC is useful for preoperative localization of parathyroid lesions.

Long-term effects of in vivo angioplasty in normal and vasospastic canine carotid arteries: pharmacological and morphological analyses

OBJECT

A canine model of hemorrhagic vasospasm of the high cervical internal carotid artery (ICA) was used to study the long-term effects of transluminal balloon angioplasty (TBA) on the structure and function of the arterial wall.

METHODS

Forty dogs underwent surgical exposure of both distal cervical ICAs, followed by baseline angiographic studies on Day 0. Dogs in Group A (20 animals) underwent simple exposure of one ICA and placement of a silicone elastomer cuff around a segment of the opposite artery. These animals underwent repeated angiography on Day 7, and then TBA was performed on the uncuffed ICA; the cuff was removed from the opposite vessel. For dogs in Group B (20 animals), blood clot-filled cuffs were placed around both ICAs, and on Day 7 angiography was repeated and TBA was performed on one randomly selected ICA. Four animals were then killed from each group, and in the remaining animals the cuffs were removed from both ICAs. On Days 14, 21, 28, and 56, four animals from each group underwent repeated angiography and were then killed to permit pharmacological and morphological analyses of the ICAs. This protocol yielded five study categories: cuffed nonblood-coated arteries not subjected to TBA, blood-coated arteries not subjected to TBA, blood-coated arteries subjected to TBA, normal arteries subjected to TBA, and control arteries obtained from the proximal ICA in each animal. The contractile responses of isolated arterial rings obtained from each ICA were recorded after treatment with potassium chloride, noradrenaline, and serotonin, whereas relaxations in response to the calcium ionophore A23187 and papaverine were recorded after tonic contraction to noradrenaline had been established. Morphological analysis was performed using scanning electron microscopy. Arteries surrounded by an empty cuff exhibited no angiographic, pharmacological, or morphological differences compared with normal arteries on any study day. Arteries surrounded by blood developed angiographically confirmed vasospasm on Day 7, with characteristic pharmacological and morphological features; resolution of these symptoms occurred by Day 21. Vasospastic arteries subjected to TBA on Day 7 remained dilated on angiographic studies, exhibited impaired responses to pharmacological agents (except for papaverine), and showed altered morphological features until Day 28. Normal arteries subjected to TBA on Day 7 remained dilated on angiographic studies, exhibited impaired responses to pharmacological agents (except for papaverine), and displayed altered morphological features until Day 14.

CONCLUSIONS

These results indicate that the canine high cervical ICA model produces consistent and reproducible vasospasm that follows a similar time course to that seen in humans. When TBA is performed in vasospastic arteries, it results in an immediate functional impairment of vascular smooth muscle that lasts for 2 weeks, with resolution at 3 weeks; morphological changes are mostly resolved 3 weeks post-TBA. In normal vessels, TBA causes functional impairment and morphological alterations that are not as severe or as long-lasting as those seen in vasospastic arteries.

A novel podophyllotoxin-derived compound GL331 is more potent than its congener VP-16 in killing refractory cancer cells

PURPOSE

GL331 is a new homolog of VP-16, and has demonstrated more efficacious anti-cancer activity in both the in vitro and in vivo lymphoma systems. To extensively explore GL331's clinical value, we furthermore evaluate the cytotoxicity and apoptosis-inducing activity of GL331 in several human cell lines from cancers that are not normally treated with VP-16.

METHODS

By MTT and clonogenic survival assays, the cytotoxicities of GL331 and VP-16 were evaluated in a variety of cell lines including nasopharyngeal, hepatocellular, gastric, colon, cervical, and neuroblastoma cancer types. Western blot analysis was performed to detect the MDR-1 level in these cell lines. By Annexin V-staining flow cytometry and detection of DNA ladders, the apoptosis-inducing activities of GL331 and VP-16 were also evaluated.

RESULTS

GL331 showed more efficacy than its congener VP-16 in killing cancer cells. The estimated ID50 of GL331 were 2.5 to 17-fold lowerthan those of VP-16. GL331 possessed more cell-killing activity even in MDR-1-overexpressing cell lines such as HCC36 and SW620. Its higher cytotoxicity could be attributed by the elevated ability to induce apoptotic cell death.

CONCLUSION

GL331's overriding drug resistance and higher cancer cell-killing activity suggest its superiority in clinical cancer therapy.

An efficient stereoselective synthesis of [3S(1S,9S)]-3-[[[9-(benzoylamino) octahydro-6,10-dioxo-6H-pyridazino-(1,2-a)(1,2)-diazepin-1-yl]-carbonyl ]amino]-4-oxobutanoic acid, an interleukin converting enzyme (ICE) inhibitor

The title compound 1 is a potent interleukin-1beta-converting enzyme (ICE) inhibitor. Recently, an efficient chiral synthesis of compound 1 has been accomplished in our labs. The overall yield of this 18-step stereoselective synthesis was 9.8%.

Monte Carlo EM for missing covariates in parametric regression models

We propose a method for estimating parameters for general parametric regression models with an arbitrary number of missing covariates. We allow any pattern of missing data and assume that the missing data mechanism is ignorable throughout. When the missing covariates are categorical, a useful technique for obtaining parameter estimates is the EM algorithm by the method of weights proposed in Ibrahim (1990, Journal of the American Statistical Association 85, 765-769). We extend this method to continuous or mixed categorical and continuous covariates, and for arbitrary parametric regression models, by adapting a Monte Carlo version of the EM algorithm as discussed by Wei and Tanner (1990, Journal of the American Statistical Association 85, 699-704). In addition, we discuss the Gibbs sampler for sampling from the conditional distribution of the missing covariates given the observed data and show that the appropriate complete conditionals are log-concave. The log-concavity property of the conditional distributions will facilitate a straightforward implementation of the Gibbs sampler via the adaptive rejection algorithm of Gilks and Wild (1992, Applied Statistics 41, 337-348). We assume the model for the response given the covariates is an arbitrary parametric regression model, such as a generalized linear model, a parametric survival model, or a nonlinear model. We model the marginal distribution of the covariates as a product of one-dimensional conditional distributions. This allows us a great deal of flexibility in modeling the distribution of the covariates and reduces the number of nuisance parameters that are introduced in the E-step. We present examples involving both simulated and real data.

Bayesian analysis and model selection for interval-censored survival data

Interval-censored data occur in survival analysis when the survival time of each patient is only known to be within an interval and these censoring intervals differ from patient to patient. For such data, we present some Bayesian discretized semiparametric models, incorporating proportional and nonproportional hazards structures, along with associated statistical analyses and tools for model selection using sampling-based methods. The scope of these methodologies is illustrated through a reanalysis of a breast cancer data set (Finkelstein, 1986, Biometrics 42, 845-854) to test whether the effect of covariate on survival changes over time.

Transfection of anti-sense complementary DNA of human epidermal-growth-factor receptor attenuates the proliferation of human non-small-cell-lung-cancer cells

The proliferation of human non-small-cell-lung-cancer (NSCLC) cells is regulated by the epidermal-growth-factor-receptor (EGFR)-mediated autocrine loop that interacts with transforming growth factor-alpha (TGF-alpha) of autocrine or paracrine origin. We have shown that EGFR expression is elevated in the brain metastatic variant of human NSCLC cells H226Br, which thereby acquire their increased sensitivity toward exogenous TGF-alpha. To determine detailed cell-phenotype changes as a result of EGFR down-regulation, H226Br cells were transfected with a human EGFR-cDNA construct encompassing an N-terminal fragment (1.8 kb) in anti-sense orientation downstream of the cytomegalovirus (CMV) promoter. The EGFR transcript expressed in the 3'-5' direction is expected to neutralize EGFR mRNA and to reduce protein expression correspondingly. The established cell lines resistant to G418 were shown integrated with the transfected construct and their proliferation rates reduced as compared with the parental cells and with those transfected with vector alone. Down-regulated EGFR expression in cells with the anti-sense construct can be confirmed by Scatchard analysis and suppressed EGFR kinase activity. The restrained-growth phenotype is also demonstrated in the prolonged G2-M phase during the cell cycle, and correlated with impairment of cell proliferation. This finding suggests that EGFR over-expression is critical in maintaining the malignant phenotype of NSCLC cells, thereby providing a valuable biomarker and potential target prevention for lung-cancer-cell proliferation.