Hypermethylation of the p16 gene in sporadic T3N0M0 stage colorectal cancers: association with DNA replication error and shorter survival

Hypermethylation in the promoter region of the p16 gene was suspected to be involved in the tumorigenesis of colorectal cancers, although its clinical and biological significance remains obscure. In this study, we collected 84 T3N0M0 stage primary colorectal cancers that were curatively resected. The clinicopathologic data were reviewed. p16 hypermethylation was determined by a methylation-specific polymerase chain reaction (PCR). p53 overexpression was detected by immunocytochemistry (ICC). The point mutations in the 12 and 13 codons of the K-ras gene were screened by restriction enzyme analysis. Loss of heterozygosity (LOH) of the DCC (Deleted in Colorectal cancer) gene was examined by PCR using primers of the DCC (18q21) microsatellite marker. The DNA replication error (RER) was examined using 7 microsatellite markers at distinct chromosomal loci. p16 hypermethylation, regarded as an indication of p16 inactivation, was evident in 24 (28.6%) of the tumors. No correlation was found between p16 hypermethylation and various clinicopathologic factors, includinig age, sex, tumor location, tumor size, growth pattern, tumor differentiation, mucin production, vascular and/or lymphatic invasion, lymphocyte infiltration of the tumor, and serum level of carcinoembryonic antigen. There was no association between p16 hypermethylation of K-ras gene mutation, p53 overexpression and LOH of the DCC gene. However, p16 hypermethylation was significantly associated with DNA RER (p = 0.01). Survival analysis revealed a significant survival disadvantage of p16-hypermethylated versus non-p16-hypermethylated tumors (p = 0.0001). These findings indicate that p16 hypermethylation plays a role in the carcinogenesis of a subset of colorectal cancers; and the presence of p16 hypermethylation predicts shorter survival in T3N0M0 stage colorectal cancers.

Polyamine-fas interactions: inhibition of polyamine biosynthesis in MRL-lpr/lpr mice is associated with the up-regulation of fas mRNA in thymocytes

MRL-lpr/lpr is a strain of mice that develops spontaneous signs of the autoimmune disease, systemic lupus erythematosus (SLE or lupus). The lpr (lymphoproliferation) defect has been identified as an insertion of an early transposon (ETn) derived sequence into the fas apoptosis gene. We studied the in vivo effects of difluoromethylornithine (DFMO), an irreversible inhibitor of the polyamine biosynthetic enzyme, ornithine decarboxylase (ODC), on the expression of fas in MRL-lpr/lpr mice as well as in congenic MRL- + / + and autoimmune NZB/W strains. Using Northern blot hybridization and reverse transcription polymerase chain reaction (RT-PCR), we found that DFMO treatment resulted in an increase in the expression of fas mRNA in the thymus of MRL-lpr/lpr mice. Using RT-PCR, we further found that the increased expression of fas was associated with the suppression of chimeric ETn/fas mRNA. With fractionated CD4 + and CD8 + T cells, we found a cell-specific effect of DFMO on chimeric ETn/fas expression in CD8 + cells. ETn/fas expression was detected in CD8+ T cells from untreated mice, but it was eliminated after DFMO treatment. HPLC analysis of polyamines showed depletion of putrescine and partial reduction of spermidine (35%) in DFMO-treated mice compared to controls. These results indicate that DFMO-mediated polyamine depletion is linked to the regulation of fas and chimeric ETn/fas in MRL-lpr/lpr mice. Elevated levels of polyamines in this strain, as found in earlier studies, may be associated with the progression of the autoimmune disease by altering the expression of fas gene or by facilitating the expression of chimeric ETn/fas. Our data also provide new mechanistic insights into the beneficial effects of DFMO on these mice.

The integration of laughter and speech in vocal communication: a dynamic systems perspective

Laughter in infant-directed speech was examined in 13 mother-infant pairs to investigate the possible co-occurrence of speech and laughter. Contrary to previous findings in adult-adult social interaction, all mothers produced speech simultaneously with laughter in up to 50% of laughs. In most of these speech-laughs the onset of laugh and speech was simultaneous. Laughter occurred on both function and content words and was more likely to occur on approximately 2 words and on utterances that were statements rather than questions or exclamations. Laughter and speech are different outcomes produced from a reorganization of the same vocal/anatomical parameters. A 3rd outcome is possible in the form of speech-laughs utilizing features from both laughter and speech. In speech-laughs, the duration of the vocalization was more likely to increase, and the changes in the utterance were likely to include 1 or more of the features of vowel elongation, syllabic pulsation, breathiness, and pitch change. These findings and individual variations in the resulting vocal output are discussed from a dynamic systems perspective. It is argued that neither speech nor laughter is dominant when both are combined, but that this is a more complex vocal outcome produced with idiosyncratic flexibility within stable temporal and physiological constraints.

Human recombinant DNA-derived antihemophilic factor (factor VIII) in the treatment of hemophilia A

BACKGROUND

Plasma-derived factor VIII concentrates used in the treatment of hemophilia A have the potential danger of transfusion-associated viral disease. The safety and efficacy of a recombinant factor VIII preparation for the treatment of this disorder were evaluated in this study.

METHODS

We compared the pharmacokinetics of plasma-derived and recombinant factor VIII in 12 previously treated subjects with severe hemophilia A.

RESULTS

The recovery and elimination half-lives of the recombinant factor VIII were equal to those of plasma-derived factor VIII. It was well tolerated via parenteral therapy, and only two mild adverse reactions (5%) were reported. No evidence of new viral infection was noted during the study period with the recombinant factor VIII.

CONCLUSIONS

The biologic activity of the recombinant factor VIII is comparable with that of plasma factor VIII concentrate. It is safe and efficacious for the treatment of hemophilia A.

In vitro effect of granulocyte-colony stimulating factor and all-trans retinoic acid on the expression of inflammatory cytokines and adhesion molecules in acute promyelocytic leukemic cells

Differentiation therapy with all-trans retinoic acid (ATRA) represents a landmark approach in the treatment of acute promyelocytic leukemia (APL). However, a potentially fatal complication of retinoic acid (RA) syndrome occurs in about a quarter of patients and its pathophysiology is still unclear. In order to investigate whether or not the treatment with ATRA leads to increased elaboration of inflammatory cytokines and adhesion molecules by the APL cells, the expression of interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha, IL-8, L-selectin and intercellular adhesion molecule-1 (ICAM-1) was examined in the APL cells after induction of differentiation with ATRA in the presence or absence of granulocyte-colony stimulating factor (G-CSF) or IL-3 in the present study. Cytokine elaboration by the treated cells was detected using both Northern blotting and enzyme-linked immunosorbent assay. Our results have shown that ATRA induces an increased expression of IL-8, IL-1beta, TNF-alpha and ICAM-1 in APL cells, which can be amplified by the addition of G-CSF. These data imply that the induction of inflammatory cytokines in APL cells may play an important role in the pathogenesis of RA syndrome. Furthermore, G-CSF, through its potent differentiating activity, may increase the risk of such complications during ATRA treatment.

Hyperinsulinemia and related atherosclerotic risk factors in the population at cardiovascular risk: a community-based study

BACKGROUND

A population-based study was conducted in Taiwan to investigate the prevalence of insulin resistance and high serum insulin concentrations and their relationships with potential atherosclerotic risk factors.

METHODS

We studied 2165 subjects, ages >35, from a community cohort.

RESULTS

The distributions of fasting insulin were skewed to the right, with higher concentrations in women than in men. As age increased, insulin increased in women, but decreased in men. As fasting insulin concentrations increased, postloading insulin, glucose, blood pressure, body mass index, waist-to-hip ratio, total cholesterol, triglycerides, LDL-cholesterol, apoprotein B, plasminogen activator inhibitor 1, tissue plasminogen activator, and fibrinogen increased, but lipoprotein(a), HDL-cholesterol, and apoprotein A1 decreased. Multiple logistic regression showed that obesity, high LDL-cholesterol, and low HDL-cholesterol were significant predictors of hyperinsulinemic status.

CONCLUSION

The study subjects with insulin resistance syndrome and related risk factors may be at risk for atherosclerosis, thrombosis, and other coronary heart diseases.

The role of vitamin E on the anti-atherosclerotic effect of fish oil in diet-induced hypercholesterolemic rabbits

The role of vitamin E on the anti-atherosclerotic effect of fish oil in diet-induced hypercholesterolemic rabbits was studied in male New Zealand white rabbits. The animals were randomly divided into six groups of 14 each according to the chow given them. Group I, control, rabbits were fed regular laboratory rabbit chow. In addition to the regular chow, Group II rabbits were fed a high (1%) cholesterol-enriched diet. Group III had the same diet as Group II plus 450 mg vitamin E/1000 g chow. Group IV also had the same diet as Group II plus 10% fish oil, but without vitamin E. Group V's diet contained 1% cholesterol, 10% fish oil, and 450 mg vitamin E/1000 g chow. Group VI had the same diet as Group V, but with 150 mg vitamin E/1000 g chow. At the end of a 6-week feeding, the ascending aorta from seven rabbits from each group was harvested for the analysis of prostanoid production, thiobarbituric acid reactive substances (TBARS), superoxide dismutase activity, and cholesterol and vitamin E levels; the same tissue from the other seven rabbits from each group was obtained for the delineation of atherosclerotic lesions by planimetry after the Sudan IV stain. The high cholesterol diet-treated rabbits had worse prostanoid synthesis and higher TBARS levels, which paralleled the severity of the atherosclerosis. Vitamin E or fish oil supplementation in a high cholesterol diet had beneficial prostanoid production, reduced aortic TBARS levels, and attenuated atherosclerotic lesions; these effects were potentiated when vitamin E and fish oil were combined together. The atherosclerotic lesion reduction in rabbits treated with high cholesterol plus fish oil and 450 mg vitamin E/1000 g chow reached statistical significance (P < 0.05) compared to high cholesterol and the same dose of vitamin E-treated rabbits. The rabbits treated with high cholesterol plus fish oil, but without vitamin E or with 150 mg vitamin E/1000 g chow showed an increased plasma creatine kinase activity at 4 (P < 0.01 and 0.05, respectively) and 6 (P < 0.001 and 0.01, respectively) week of feeding. These results suggest that vitamin E and/or fish oil attenuate atherosclerosis in high cholesterol-fed rabbits; vitamin E and fish oil potentiated the effect of each other. Furthermore, without sufficient vitamin E supplementation, rabbits treated with high cholesterol plus fish oil will show an elevation of plasma creatine kinase activity.

Infrequent p53 mutations in patients with areca quid chewing-associated oral squamous cell carcinomas in Taiwan

Mutations in the conserved regions (exons 5-9) of the p53 gene were investigated in 37 untreated human primary oral squamous cell carcinomas (SCCs) using polymerase chain reaction-single strand conformation polymorphism and DNA sequencing analyses. P53 mutations were detected in 2 of 37 (5.4%) oral SCC cases. One tumor sample (case 23) showed a mis-sense point mutation at codon 177, changing CCC to CTC, which resulted in a substitution of proline to leucine in the p53 protein. The other tumor (case 33) had a point mutation at codon 266, changing GGA to AGA and causing a substitution of glycine to arginine in the p53 protein. These two patients with p53 mutations did not have an areca quid chewing habit. These results suggest that mutations in the p53 gene may not play a role in the pathogenesis of human oral SCCs in Taiwan. Recently, we have shown that positive p53 staining was observed in 47 of 81 (58%) cases of oral SCC. The discrepancies between positive p53 protein staining and the low prevalence of p53 mutation in oral SCCs indicate that other mechanism(s) are involved in p53 overexpression.

Investigation of chromosomal aberrations in hepatocellular carcinoma by fluorescence in situ hybridization

Molecular cytogenetic approaches have been applied only rarely in the characterization of hepatocellular carcinoma (HCC). The aim in this study was to evaluate aberrations, particularly deletions, of specific chromosomal regions in HCC. Dual-color fluorescence in situ hybridization (FISH) was performed on intact nuclei from touch preparations of 17 HCCs and 1 hepatic adenoma. Each touch preparation was hybridized with a digoxigenin-labeled centromere probe and a biotin-labeled unique sequence probe from the same chromosome. This approach permitted the simultaneous evaluation of ploidy changes and chromosome arm deletions. Eight noncentromeric chromosome regions, 3p14, 4q21, 6q14, 6q21, 8p12, 8p22, 9p21, and 9p24 were selected for study on the basis of their having been implicated as tumor suppressor regions in HCC or other common types of carcinoma. Together with the 5 corresponding centromeric probes on chromosomes 3, 4, 6, 8, and 9, a total of 13 chromosome loci were evaluated. All cases of hepatocellular carcinoma showed at least one deletion or aneuploidy. The hepatic adenoma was all diploid. Chromosome 4q21 showed the highest rate of deletion (76.5%) and aneusomy (88%). The second and the third were chromosome 8p22 and 6q14, which showed 59% and 47% of deletion, respectively. A 4q21 deletion is also the most frequent single chromosome aberration. Prominent tumor heterogeneity and variable deletion patterns were noted. Interphase FISH was an efficient means for evaluating numerical and structural chromosome aberrations in HCCs. Most HCCs contained deletions of known tumor suppressor regions (4q and 8p), and a novel deletion hotspot was demonstrated on chromosome band 6q14.

Lipoprotein (a) level in the population in Taiwan: relationship to sociodemographic and atherosclerotic risk factors

To examine the lipoprotein(a) (Lp(a)) level in the Taiwanese population and its association with cardiovascular risk factors, 1703 men and 1899 women aged 35 years and above were enrolled in a community-based study cohort established between 1990 and 1991. The distributions of Lp(a) levels were skewed to the right, and females were more likely than males to have Lp(a) levels greater than 30 mg/dl (14.3% versus 11.6%, P < 0.05). The Lp(a) level increased with age. Socioeconomic status did not seem to have consistent influence on the level of Lp(a). Smoking and alcohol use also had no effect on Lp(a) levels. Multivariate analysis indicated that older age and high level of low-density-lipoprotein cholesterol corresponded to an elevated Lp(a) level, while hypertriglyceridemia, low high-density-lipoprotein cholesterol level, obesity and high insulin resistance corresponded to a lower Lp(a) level. In univariate analysis, hyperinsulinemia was negatively associated with Lp(a) level (-0.107, P < 0.01) only in males. In females, use of oral contraceptive lowered Lp(a) levels, but menopause did not change Lp(a) levels. We also found that different correlation patterns existed for selected coagulation profiles between sexes. There was a significant correlation between Lp(a) and fibrinogen levels in males (0.154, P < 0.001) but not in females (0.007, P > 0.05). These data provided clues for investigating atherosclerotic risk factors and coagulation parameters for the Taiwanese population.

Clinicopathologic and carcinogenetic appraisal of DNA replication error in sporadic T3N0M0 stage colorectal cancer after curative resection

BACKGROUND/AIMS

DNA replication error (RER) was found to play a role in the carcinogenesis of a subset of sporadic colorectal cancers. This study was conducted to evaluate the clinicopathologic implications of RER in T3N0M0 stage colorectal cancers. To better understand the carcinogenesis of sporadic colorectal cancer, the RER status was further correlated with the alterations of K-ras, p53 and deleted in colorectal cancer (DCC) genes which were frequently involved in the adenoma-carcinoma sequence.

METHODOLOGY

Seventy-eight patients with curatively resected T3N0M0 stage sporadic colorectal cancer were accumulated. The stored frozen tissues were retrieved for analyses of 1) microsatellite instability at 7 distinct chromosomal loci, 2) loss of heterozygosity at DCC gene, 3) K-ras gene mutation, 4) p53 expression, and 5) DNA content. The RER status was correlated with various clinicopathologic and molecular genetic factors. The survival of patients stratified by RER status was analyzed by Kaplan-Meier estimator.

RESULTS

The RER-positive tumor was detected in 32.1% (25/78) of patients. The RER-positive cancer patients presented with distinct clinicopathologic features including young age of tumor onset, proximal tumor location, mucin production in histology, a higher rate of synchronous and metachronous colorectal cancers, and an increased incidence of extracolonic primary cancer. Patients with RER-positive tumor were found to have an improved prognosis with the 5-year survival probability of 76% and 45% in RER-positive and RER-negative groups, respectively (p < 0.05). The RER-positive tumors tended to have normal p53 expression, DNA diploidy, and a lower DNA index. The rate for the loss of heterozygosity of DCC gene was significantly lower in RER-positive tumors. RER status was not associated with K-ras mutation.

CONCLUSIONS

The clinicopathologic features and carcinogenesis of RER-positive sporadic colorectal cancers were considered different from those of RER-negative tumors. The presence of RER may identify a subset of less aggressive tumors with good prognosis in T3N0M0 stage colorectal cancers.

Radiation therapy in primary central nervous system lymphoma

BACKGROUND

Treatment of primary central nervous system lymphoma (PCNSL) in Chinese individuals has rarely been reported. Therefore, this article presents our experience in managing PCNSL with radiotherapy.

METHODS

A thorough review was made of the medical records of 13 patients diagnosed with PCNSL at Kaohsiung Chang Gung Memorial Hospital from 1988 through 1997. The clinical characteristics, treatment modalities, and results were analyzed as well.

RESULTS

Thirteen patients diagnosed with PCNSL were identified, of which 10 cases originated in the brain whereas three were of spinal origin. Seven of the patients were man and six were women, with a mean age of 54.9 +/- 13.1 years (range 29 to 74 years). Diffuse large cell lymphoma (11 cases) was the most common histology. Limb weakness (11 cases) and headache (7 cases) were the most common complaints at presentation. Nine patients received radiation therapy alone and four patients received radiation therapy plus chemotherapy after surgical resection or biopsy. Follow-up computed tomography (CT) scans 3 to 4 months after the completion of radiotherapy revealed that nine patients (69%) had a complete response and four (31%) had a partial response. Local recurrence occurred in five patients (56%) treated with radiation therapy alone and in one patient (25%) treated with combined modalities. The overall actuarial survival rate was 54% at 2 years and 27% at 5 years.

CONCLUSION

Results in this study indicate that the initial response to radiotherapy is satisfactory. However, a local relapse frequently occurs. Future considerations should focus on new modes of treatment, such as three-dimensional conformal radiation therapy for dose escalation or a combination of chemotherapy and radiotherapy.

Reappraisal of K-ras and p53 gene mutations in the recurrence of Dukes' B2 rectal cancer after curative resection

BACKGROUND/AIMS

Recurrence of rectal cancer remains a major clinical problem. This study was conducted to evaluate the impact of K-ras and p53 mutations on the recurrence of rectal cancer.

METHODOLOGY

A total of 166 resected Dukes' B2 stage rectal carcinomas were collected between January 1990 and April 1994. The stored frozen tissues were retrieved for immunocytochemistry of p53 and genomic analysis of K-ras and p53 genes. The data of K-ras and p53 gene mutations were correlated with clinicopathological variables. The concordance of immunocytochemistry with genomic analysis in the survey of p53-mutations was examined. The follow-up data were analyzed by Kaplan-Meier estimator.

RESULTS

Sixty-nine patients (41.6%) developed recurrent tumor. A significantly higher recurrence rate (p = 0.0013) and shorter median recurrence time were noted in p53 mutated than non-mutated cancers. Mutations in K-ras gene do not significantly increase the risk of tumor recurrence (p = 0.1702). K-ras and p53 mutations are not associated with clinicopathological parameters (p > 0.05). Kappa statistic indicates highly significant reproducibility between immunocytochemistry and genomic analysis for p53 mutations (p < 0.0001).

CONCLUSIONS

Presence of p53 mutation significantly increases the recurrence rate and shortens the recurrence time of the resected rectal cancers. Pre-operative routine check for p53 mutations by immunocytochemistry may be beneficial in choosing the optimal surgical strategy for rectal cancer.

Tissue hepatocyte growth factor and proliferating cell nuclear antigen in hepatocellular carcinoma

To better understand the roles of hepatocyte growth factor (HGF) and proliferating cell nuclear antigen (PCNA) in hepatocellular carcinoma (HCC), 37 surgically resected HCCs and corresponding nontumorous liver tissue specimens were collected and the expression of these two factors was quantified by Western blot analysis. Both HGF and PCNA expression levels were significantly higher in tumor tissue than in nontumorous liver tissue. However, their expression levels in HCC tissue and nontumorous tissue did not show any significant correlation with the recurrence of HCC. In addition, HGF and PCNA did not correlate with Edmondson's grade, invasiveness of tumor, presence of tumor capsule, or tumor size. No correlation was found between the expression levels of HGF and PCNA in HCC tissue. We conclude that, although both HGF and PCNA are present at higher levels in HCC tissue than in nontumorous liver tissue, they play little role in the clinicopathologic manifestations of this tumor. HGF appears to contribute little, if at all, to the proliferative activity of HCC cells.

Infant arousal in an en-face exchange with a new partner: effects of prematurity and perinatal biological risk

Very low birth weight (VLBW) infants of higher (n = 18) and lower (n = 29) perinatal biological risk were contrasted at 4 months adjusted age with healthy full-term infants (n = 32) in their arousal during a standardized peekaboo game with an examiner. VLBW infants showed less positive arousal, more negative arousal, and 3 mixtures of behavioral cues across the peekaboo game seldom seen for full-term infants-strong cues of both positive and negative arousal, strong cues of negative arousal alone, and no strong cues of either positive or negative arousal. Contrary to expectations, perinatal biological risk did not strongly predict variations in arousal within the VLBW group. Possible changes in how internal and external sources of arousal are integrated provide one explanation for the presence of strong relationships between perinatal biological risk and social responsiveness near term age and their disappearance by 4 months of age.

Rhinacanthin-Q, a naphthoquinone from Rhinacanthus nasutus and its biological activity

The continuing investigation of the root of Rhinacanthus nasutus afforded a 1,4-naphthoquinone ester, rhinacanthin-Q, accompanied by twenty-four known compounds. The structure was elucidated on the basis of spectroscopic analyses. The cytotoxicity and antiplatelet effect of this compound was also discussed.

Mechanical environment associated with rotator cuff tears

A simplified 2-dimensional finite element model was used to investigate the stress environment in the supraspinatus tendon. The extrafibrillar matrix and collagen fiber were modeled with fiber-reinforced composite elements. The stress was evaluated at humeroscapular elevation angles of 0 degree, 30 degrees, and 60 degrees. Two acromion conditions were simulated. In the first set of conditions there was no subacromial impingement. In the second set there was subacromial impingement of the bursal side. Impingement was simulated by producing a 1-mm indentation on the bursal surface, an indentation similar to the type of impingement associated with deltoid contraction. The results demonstrated that subacromial impingement generates high stress concentrations in and around the critical zone. Such high stress could initiate a tear; tears that result from stress point to an extrinsic mechanism. However, we found that high stress and potential tears caused by impingement may occur on the bursal side, the articular side, or within the tendon. This result is unaccounted for by traditional mechanical models in which only bursal-sided partial tears are initiated by subacromial impingement.

Neurophysiological basis of sympathetic nerve-preserving surgery for lower rectal cancer--a canine model

BACKGROUND/AIMS

The relative contribution and interrelated compensation of sympathetic signals among sympathetic components in pelvic plexus remain undefined. This study was designed to investigate the genitourinary function in response to autonomic nerve preservation and severance using a canine model.

METHODOLOGY

Eighteen mongrel dogs were randomly divided into 3 groups which received severance of the hypogastric nerves on either the right side, left side, or on both sides. The hypogastric nerves and sacral sympathetic trunks were electrically stimulated and the contraction pressure of the internal urethral orifice was measured immediately, at 1- and 3-month intervals. The ejaculation function and the length of time required to reach sexual orgasm were evaluated by manual penis-stimulation.

RESULTS

The difference between the left and right sides of the normal hypogastric nerve in contribution to sympathetic signals was insignificant. Compared with the hypogastric nerve, the bilateral sacral sympathetic trunks were functionally trivial in controlling the closure of the internal urethral orifice. The preserved side of the hypogastric nerve compensated for the loss of sympathetic signals of the severed side within 1 month and, thereafter, remained stationary. In contrast, the functional compensation of bilateral sacral sympathetic trunks for the severed bilateral hypogastric nerves was insignificant. When the hypogastric nerve was preserved in one or both sides, all dogs maintained normal antegrade ejaculation. If bilateral hypogastric nerves were severed, 50.0% (3/6) of the dogs lost both emission and ejaculation function; 33.3% (2/6) presented with retrograde ejaculation; and, 16.7% (1/6) presented with combined retrograde ejaculation and reduced antegrade ejaculation. The time required to reach sexual orgasm was not affected by the severance of the hypogastric nerve.

CONCLUSIONS

The normal genitourinary function could be maintained only when at least one side of the hypogastric nerve was preserved.

Os supratrochlear dorsale of the elbow: a report of two cases

The os supratrochlear dorsale, an accessory ossicle of the elbow, has rarely been described in the literature. Rather than being caused by trauma, it is subject to trauma by elbow extension with secondary chondrometaplasia, resulting symptomatology. The aim of this report is to remind readers that its presence is crucial for both diagnostic and therapeutic purposes. Arthroscopic removal may be required to relieve persistent pain, catching and limited range of motion.

Evaluation of metal ion release and corrosion resistance of ZrO2 thin coatings on the dental Co-Cr alloys

OBJECTIVES

The aim of this study was to determine if electrolytic ZrO2 thin coatings increased the corrosion resistance and decreased the metal ion release of dental cobalt-chromium alloys.

METHODS

Dental Co-Cr alloys were electrolytically deposited with ZrO2 ceramic coatings using a 0.0625 M ZrO(NO3)2 solution, at various potentials, for 500 s. The electrolytic ZrO2 gel-coated specimens were annealed at 723 K for 1 h in air. Scanning electron microscopy (SEM) was used to observe the morphology of the ZrO2 ceramic coatings on Co-Cr alloys. A dynamic polarization test was used to compare the corrosion resistance of the ZrO2 coated and uncoated Co-Cr alloys in artificial saliva. Metal ion concentrations were determined with graphite furnace atomic absorption spectroscopy (AAS).

RESULTS

The SEM micrographs showed that the Co-Cr alloy can be coated with zirconia oxide at -0.7 V more homogeneously and more completely than at -1.5 V. The polarization curves indicated that the ZrO2 coating on Co-Cr alloys annealed at 723 K for 1 h in air exhibited better corrosion resistance in artificial saliva. The results of the AASs showed that the ZrO2-coated Co-Cr alloys decreased chromium ion release levels, as compared with the uncoated Co-Cr alloys. The scratch test indicated a good bond strength between the ZrO2 and Co-Cr alloy.

SIGNIFICANCE

The electrolytically deposited ZrO2 coatings on Co-Cr alloys may improve the corrosion resistance and decrease the release of metal ions. It is suggested that the electrolytic ZrO2 coating method could have a widespread application in dentistry in the future.

The influence of cryopreservation on cytokine production by human T lymphocytes

Human T lymphocytes isolated from peripheral blood were cryopreserved at -196 degreesC for different periods of 3, 14, 21, 35, and 50 days. Viability and cytokine-producing activity of T cells were examined before and after cryopreservation. A high recovery (90 +/- 1%) of viable T cells was obtained at each frozen period, indicating that a 10% loss of cells was due to the freezing process rather than the duration of cryopreservation. There was no difference in cell cycle distribution between PHA-treated fresh and frozen lymphocytes. Resting human T cells produced little or no cytokine. After stimulation of fresh T cells with PHA, an apparent increase in cytokine production was noted in IL-2 (35.5 +/- 8.3 pg/ml), IL-6 (1280.4 +/- 64.7 pg/ml), tumor necrosis factor-alpha (874.3 +/- 71.7 pg/ml), interferon-gamma (58.9 +/- 2.2 pg/ml), and granulocyte macrophage-colony-stimulating factor (59.5 +/- 4.4 colonies/5 x 10(4) bone marrow cells). Compared with PHA-activated fresh T cells, all the above cytokines did not diminish in their levels in conditioned medium from PHA-treated frozen T cells thawed at each storage period, suggesting that cryopreservation could well retain the cytokine-producing activity of human T lymphocytes. In addition, our results also revealed that cryopreservation rendered T lymphocytes more responsive to PHA in IL-2 production than fresh T cells.

Association of downregulation of cyclin D1 and of overexpression of cyclin E with p53 mutation, high tumor grade and poor prognosis in hepatocellular carcinoma

BACKGROUND/AIMS

The major regulatory events leading to cell proliferation occur in the G1 phase of cell cycle, and the deranged expression of G1 cyclins is related to oncogenesis. In this study, we analyzed the aberrant expressions of cyclins D1 and E, and their role in hepatocellular carcinoma.

METHODS

We examined paired hepatocellular carcinoma and liver RNAs taken from 71 patients who had been followed for more than 4 years after tumor resection, using reverse transcription-polymerase chain reaction supplemented with Northern blotting and immunohistochemistry. The genetic alterations of the p53 gene were also studied.

RESULTS

Downregulation of cyclin D1 mRNA was detected in 29 hepatocellular carcinomas (40.8%), while overexpression was detected in only 4 hepatocellular carcinomas (5.6%). Downregulation of cyclin D1 was associated significantly with large hepatocellular carcinomas (p=0.0006) and poorly differentiated (grades III-IV) hepatocellular carcinoma (p=0.057), but not seen in any of 15 minute hepatocellular carcinomas (< or =2.5 cm in size). Cyclin E mRNA was overexpressed in 40 hepatocellular carcinomas, regardless of tumor size. Overexpression of cyclin E was significantly associated with poorly differentiated and invasive hepatocellular carcinoma (p=0.001 and p=0.015, respectively). Downregulation of cyclin D1 and overexpression of cyclin E were significantly associated with the p53 mutation (p=0.023 and p=0.005, respectively). Hepatocellular carcinomas expressing both downregulation of cyclin D1 and overexpression of cyclin E had the worst 4-year survival (p<0.03), and higher frequencies of the p53 mutation (p<0.001), large hepatocellular carcinoma (p<0.001), and invasive tumor (p<0.01).

CONCLUSIONS

The deranged expressions of G1 cyclins correlate with the p53 mutation, tumor progression, and tumor biologic behavior of hepatocellular carcinoma. Overexpression of cyclin E occurs early, and downregulation of cyclin D1 late in hepatocellular carcinoma growth.

Vitamin E supplementation attenuates myointimal proliferation of the abdominal aorta after balloon injury in diet-induced hypercholesterolemic rabbits

The effects of vitamin E supplementation in a dose of 450 mg/1000 g chow on the myointimal proliferation of the abdominal aorta after balloon injury were studied in 4 groups of rabbits (24 each). The animals were fed regular diet, regular diet plus vitamin E, 1% cholesterol-enriched diet, and 1% cholesterol-enriched diet plus vitamin E. Each animal underwent a balloon injury of the abdominal aorta and left common iliac artery after 2 weeks of feeding. The animals remained on their respective diets thereafter. In 8 balloon-injured and 8 sham-operated animals of each group, the abdominal aortas were harvested 3 days after the procedure for the analysis of prostacyclin and thromboxane A2 synthesis, thiobarbituric acid reactive substances (TBARS) levels, enzyme activities of glutathione reductase (GR) and glutathione peroxidase (GP) as well as reduced (GSH) and oxidized (GSSG) glutathione levels, 3H-thymidine uptake, cholesterol as well as vitamin E contents. In the other 8 balloon-injured rabbits of each group, the tissue was harvested 3 weeks later for the morphometric study. In dependent of high cholesterol feeding, the vitamin E-treated rabbits had lower aortic production of thromboxane B2, higher 6-keto-PGF1 alpha and higher 6-keto-PGF1 alpha/thromboxane B2 ratios in both procedures. The aortic TBARS levels of the rabbits treated high cholesterol alone were significantly higher than the other three groups in both procedures. Balloon injury had a trend to increase TBARS levels and had significantly higher 3H-thymidine uptake (each p < 0.001) than sham operation in each group. Vitamin E supplement to high cholesterol diet or regular chow reduced aortic TBARS levels (p < 0.005 and 0.01, respectively) and 3H-thymidine uptake (p < 0.05 and 0.01, respectively), as well as attenuated myointimal proliferation of the abdominal aorta and left common iliac artery after balloon injury; but only supplement to high cholesterol diet reached statistical significances (both p < 0.05 compared to rabbits fed high cholesterol alone). These results suggest that vitamin E supplement changes prostanoid metabolism to a favorable pattern and reduces lipid peroxidation of the abdominal aortic wall, thus attenuates myointimal proliferation after balloon injury; these presentations are particularly obvious in diet-induced hypercholesterolemic rabbits.

Cerebral air embolism complicating bilevel positive airway pressure therapy

A 13 yr old male with acute lymphoblastic leukaemia who received bilevel positive airway pressure ventilation via a face mask for post-transplant pneumonitis developed subcutaneous emphysema, radiographic evidence of pulmonary interstitial emphysema, pneumomediastinum and 6 h later, right hemiparesis and focal livedo reticularis. This case illustrates that severe barotrauma may complicate noninvasive bilevel positive airway pressure ventilation.