Biomechanical signals exert sustained attenuation of proinflammatory gene induction in articular chondrocytes

OBJECTIVES

Physical therapies are commonly used for limiting joint inflammation. To gain insight into their mechanisms of actions for optimal usage, we examined persistence of mechanical signals generated by cyclic tensile strain (CTS) in chondrocytes, in vitro. We hypothesized that mechanical signals induce anti-inflammatory and anabolic responses that are sustained over extended periods.

METHODS

Articular chondrocytes obtained from rats were subjected to CTS for various time intervals followed by a period of rest, in the presence of interleukin-1beta (IL-1beta). The induction for cyclooxygenase (COX-2), inducible nitric oxide synthase (iNOS), matrix metalloproteinase (MMP)-9, MMP-13 and aggrecan was analyzed by real-time polymerase chain reaction (PCR), Western blot analysis and immunofluorescence.

RESULTS

Exposure of chondrocytes to constant CTS (3% CTS at 0.25 Hz) for 4-24 h blocked more than 90% (P<0.05) of the IL-1beta-induced transcriptional activation of proinflammatory genes, like iNOS, COX-2, MMP-9 and MMP-13, and abrogated inhibition of aggrecan synthesis. CTS exposure for 4, 8, 12, 16, or 20 h followed by a rest for 20, 16, 12, 8 or 4h, respectively, revealed that 8h of CTS optimally blocked (P<0.05) IL-1beta-induced proinflammatory gene induction for ensuing 16 h. However, CTS for 8h was not sufficient to inhibit iNOS expression for ensuing 28 or 40 h.

CONCLUSIONS

Data suggest that constant application of CTS blocks IL-1beta-induced proinflammatory genes at transcriptional level. The signals generated by CTS are sustained after its removal, and their persistence depends upon the length of CTS exposure. Furthermore, the sustained effects of mechanical signals are also reflected in their ability to induce aggrecan synthesis. These findings, once extrapolated to human chondrocytes, may provide insight in obtaining optimal sustained effects of physical therapies in the management of arthritic joints.

Alternative Decision Analysis Modeling in the Economic Evaluation of Tumor Necrosis Factor Inhibitors for Rheumatoid Arthritis

OBJECTIVES

To provide a review of the studies that use decision models in the economic evaluation of tumor necrosis factor (TNF) inhibitors in rheumatoid arthritis (RA) and to address some important issues surrounding the choice of such modeling techniques in these economic evaluations.

METHODS

A systematic literature search was conducted by 1 author from the literature published from January 1996 to March 2005 through Medline, Embase, and Cochrane library databases.

RESULTS

The review yielded 29 studies that used decision models. Only 10 studies used a decision model in the economic analysis of the TNF inhibitors and were included in the final review. Decision model types included the following in the review articles: decision tree (2), Markov model (7), and discrete event simulation (1). These models vary in complexity and their choice depends on the course of disease, the impact of treatment, and the available data.

CONCLUSIONS

Based on the results derived from alternative modeling techniques, it is safe to say that all methods can provide useful information with regard to economic evaluations of TNF inhibitors. Even though different modeling techniques provide an appropriate representation of available data, their results should be interpreted contingent on the input data, assumptions, sensitivity analyses, and other alternative scenario analyses.

RELEVANCE

The transparency in the models will encourage end users such as policymakers and prescribers to make informed judgments regarding the appropriateness of the methods and the validity of the results.

IL-6 protects enterocytes from hypoxia-induced apoptosis by induction of bcl-2 mRNA and reduction of fas mRNA

Interleukin-6 (IL-6) has been shown to rescue enterocytes from hypoxia-induced apoptosis when given orally following hemorrhagic shock. In vitro models using an intestinal epithelial cell line (IEC-6) cultured with lipopolysaccharide (LPS) under low O2 conditions, to mimic intestinal conditions, show that these cells also undergo apoptosis, which can be reduced by subsequent culture with IL-6. To examine further the mechanisms of rescue, we cultured normal rat intestinal epithelial cells (IEC-6) under both normoxic and hypoxic conditions and analyzed their responses to LPS and IL-6. We showed that IEC-6 expressed IL-6 receptor on its surface. Further, IEC-6 cells could be rescued from hypoxia-induced apoptosis by co-culture with IL-6. RNase protection assay (RPA) examination revealed that under hypoxic conditions, IEC-6 cells that were resistant to apoptosis showed reduced fas expression and increased bcl-2 expression after co-culture with LPS+IL-6.

Restrictive cardiomyopathy due to primary plasma cell leukemia

The causes of restrictive cardiomyopathy are numerous, of which neoplastic infiltration is also known. Plasma cell leukemia is considered as the, most severe form of multiple myeloma, is an extremely rare condition. Among them, primary plasma cell leukemia has got an incidence of one in one million only. We report a case summary of a patient who was admitted with clinical features suggestive of restrictive cardiomyopathy, the underlying disorder was primary plasma cell leukemia. With chemotherapy the restrictive physiology was relieved supporting the diagnosis of plasma cell infiltration in the myocardium. We report this case due to rarity of the disease itself and its rare presentation.

Recurrent Miller Fisher syndrome

Miller Fisher syndrome (MFS) is a variant of Guillan Barre syndrome characterized by the triad of ophthalmoplegia, ataxia and areflexia. Recurrences are exceptional with Miller Fisher syndrome. We are reporting a case with two episodes of MFS within two years. Initially he presented with partial ophthalmoplegia, ataxia. Second episode was characterized by full-blown presentation characterized by ataxia, areflexia and ophthalmoplegia. CSF analysis was typical during both episodes. Nerve conduction velocity study was fairly within normal limits. MRI of brain was within normal limits. He responded to symptomatic measures initially, then to steroids in the second episode. We are reporting the case due to its rarity.

Experimental and theoretical multiple kinetic isotope effects for an SN2 reaction. An attempt to determine transition-state structure and the ability of theoretical methods to predict experimental kinetic isotope effects

The secondary alpha-deuterium, the secondary beta-deuterium, the chlorine leaving-group, the nucleophile secondary nitrogen, the nucleophile (12)C/(13)C carbon, and the (11)C/(14)C alpha-carbon kinetic isotope effects (KIEs) and activation parameters have been measured for the S(N)2 reaction between tetrabutylammonium cyanide and ethyl chloride in DMSO at 30 degrees C. Then, thirty-nine readily available different theoretical methods, both including and excluding solvent, were used to calculate the structure of the transition state, the activation energy, and the kinetic isotope effects for the reaction. A comparison of the experimental and theoretical results by using semiempirical, ab initio, and density functional theory methods has shown that the density functional methods are most successful in calculating the experimental isotope effects. With two exceptions, including solvent in the calculation does not improve the fit with the experimental KIEs. Finally, none of the transition states and force constants obtained from the theoretical methods was able to predict all six of the KIEs found by experiment. Moreover, none of the calculated transition structures, which are all early and loose, agree with the late (product-like) transition-state structure suggested by interpreting the experimental KIEs.

Primary antiphospholipid antibody syndrome presenting as venous infarct and deep vein thrombosis

We report the case of a young lady with primary antiphospholipid antibody syndrome, who had two spontaneous abortions and cerebral venous thrombosis and subsequently deep vein thrombosis of the leg veins. Three classes of antiphospholipid antibodies (IgG, IgM, IgA) were elevated. There was no clinical or laboratory evidence for other autoimmune or systemic illnesses. We are presenting the case due to the rarity of the same.

The use of pharmacy immunization services in rural communities

Pharmacies have been recommended as alternative sites for the delivery of immunization services, especially to medically underserved adults and children in inner cities and rural areas. Currently, 35 of 50 states in the USA have legalized the administration of vaccines by pharmacists on the basis of certain training requirements and specific protocols. Since the role of pharmacists is expected to expand, it is important to assess the factors that would enable them to improve the delivery of immunization services and the acceptance of these services by communities. It is particularly important for pharmacists to have knowledge of community circumstances and be able to respond to community needs. This case study of a pharmacy immunization programme (PIP) in rural West Virginia assessed how well pharmacists were aware of community circumstances and which community factors affected the utilization of pharmacy-delivered immunizations. Our findings suggest that although pharmacists played important roles as facilitators, hosts and motivators in PIP, they overestimated the trust placed in them by community members. The convenient locations of pharmacies and the convenient times when they offered immunization services were found to be the determining factors of mothers' decisions to take their children to these places for their vaccinations. The study concludes that as the use of pharmacies as sources of immunization is expected to continue to expand, pharmacists should take these factors into consideration when they decide to offer immunizations.

Photosynthetic responses of soybean to soybean aphid (Homoptera: Aphididae) injury

The soybean aphid, Aphis glycines Matsumara, was discovered in the United States in the summer of 2000. Since that initial discovery, the aphid has spread across northern soybean production regions. In 2001, we examined the physiological responses of soybeans to low aphids densities (fewer than 50 aphids/leaf). In this study, we determined photosynthetic rates, leaf fluorescence responses, and photosynthetic responses to variable carbon dioxide and light levels. In addition, analyses for chlorophyll content and stable carbon isotope ratios were used to differentiate potential differences in stomatal versus mesophyll limitations to photosynthesis. We observed rate reductions of up to 50% on infested leaflets, including lealets with no apparent symptoms of aphid injury (such as chlorosis). Differences in fluorescence data indicated that photoelectron transport was not impaired. These results indicate that substantial physiological impact on soybean is possible even at low aphid densities. Also, the conventional view of aphid injury acting through reductions in chlorophyll content and light-harvesting reactions of photosynthesis is not supported by our findings in this system.

Compliance rates and predictors of cancer screening recommendations among Appalachian women

High rates of morbidity and mortality in the Appalachian region of the country warrant examination of the preventive care behavior of its residents. This study determined compliance rates for breast and cervical cancer screening recommendations for women residing in Appalachian states and identified predictors of such compliance using the Behavioral Risk Factor Surveillance System data (1995-97). Healthy People 2000 goals were used as benchmarks for progress. Appalachian women have made good progress toward goals pertaining to breast and cervical cancer screening. Compliance with other preventive services, having insurance coverage, residing in urban areas, better self-reported health, and higher education were independently associated with increased odds of compliance with annual-screening recommendations. Risk factors of obesity and smoking were associated with decreased odds of compliance. Findings should be useful to health care providers, policy makers, and researchers in their efforts to educate, encourage, and promote preventive care behavior among residents of Appalachia.

High and low serum potassium associated with cardiovascular events in diuretic-treated patients

OBJECTIVE

To determine the relationship of moderately high and low concentrations of serum potassium with cardiovascular disease events among treated hypertensive patients.

DESIGN

An observational cohort study with prospectively collected data.

SETTING

A worksite treatment program for mild hypertension.

PATIENTS

All program participants with baseline and at least one annual follow-up measure of serum potassium; 7,653 individuals with 6.7 years mean follow-up met these criteria.

MAIN OUTCOME MEASURES

Outcome events were admissions to hospital because of cardiovascular disease, and deaths. The research question regarding serum potassium categories was formulated after data collection. The serum potassium concentration (mean +/- 2SD) of the study population was used to define low (3.0-3.5 mmol/l), high (5.1-5.9 mmol/l) and middle (3.6-5.0 mmol/l) categories.

RESULTS

Individuals with low (n = 146) and high (n = 226) serum potassium had significantly greater risk for cardiovascular disease events than those in the middle category (n = 7,281). Multivariate adjusted hazard ratios from Cox models were 2.6 [95% confidence intervals (CI) 1.5-4.4] for the low potassium group and 1.7 (95% CI 1.0-2.7) for the high potassium group, with the middle group as reference. Among 1,679 individuals who regularly took diuretics, hazard ratios were 4.3 (95% CI 2.4-7.9) for the low potassium group and 6.7 (95% CI 2.8-15.9) for the high group. Neither low nor high potassium was significantly associated with outcome events for those not regularly using diuretics.

CONCLUSIONS

These data confirm an association of mild hypokalemia with increased cardiovascular events among diuretic-treated hypertensive patients. In addition, we have found a similar increased cardiovascular risk associated with modest hyperkalemia among these patients. Whether modification of these serum potassium concentrations would alter that risk remains to be determined.

Pulse pressure: a predictor of cardiovascular mortality among young normotensive subjects

Wide pulse pressure has been associated with increased cardiovascular disease events among hypertensive subjects. To test the hypothesis that this association also exists among normotensive subjects, data from the first National Health and Nutritional Examination Survey and the 1992 Epidemiological Follow-up Study were analyzed. The study group included 7346 participants, aged 25-74 years, with baseline blood pressure levels <140/90 mmHg and without a history of hypertension. Deaths from cardiovascular disease and all other causes were determined. At entry, mean age and blood pressure level were 43.4 years and 118/76 mmHg. During an average follow-up period of 17.4 years, there were 1443 (19.6%) deaths, 557 of them ascribed to cardiovascular disease. Age-race-adjusted cardiovascular mortality was significantly higher for those in the highest quartile of pulse pressure (> or = 50 mmHg). However, after stratification into age <55 years and > or = 55 years, and controlling for other cardiovascular risk factors, increased pulse pressure was associated with cardiovascular mortality only in younger men and women. In these subjects, men and women with pulse pressures > or = 48, and > or = 46 mmHg, respectively, had a relative risk (95% confidence in terval) of 2.35 (1.21-4.38) and 2.90 (1.34-4.98) for cardiovascular mortality with those with pulse pressures of less than 36 and 34 mmHg, respectively (p < 0.05) as reference. While systolic blood pressure by itself was a weaker predictor of cardiovascular mortality than pulse pressure, diastolic and mean arterial pressure were not predictive at all. No measure of blood pressure was related to mortality in those aged > or = 55 years. In conclusion, among young subjects, but not older normotensive persons, at very low risk of cardiovascular disease, a wide pulse pressure is associated with increased cardiovascular mortality.

History of treatment for depression: risk factor for myocardial infarction in hypertensive patients

OBJECTIVE

Psychological factors have been suspected of contributing to the development of cardiovascular disease. This study examined the relationship between a self-reported history of treatment for depression and subsequent myocardial infarction among treated hypertensive patients.

METHODS

Participants (5564) in a union-sponsored, hypertension control program in New York City, who entered the program during 1981-1994 without a history of cardiovascular disease and who were asked whether they had been treated for depression, were followed in a prospective cohort study. The primary outcome of interest was hospitalization or death due to myocardial infarction.

RESULTS

At entry, 3.5% of men and 6.4% of women reported a history of treatment for depression. During 4.9 years (average) of follow-up, 112 fatal and nonfatal myocardial infarctions were recorded. The sex-adjusted relative risk of myocardial infarction was 2.24 (confidence interval = 1.13-4.45). Controlling for known cardiovascular risk factors with multivariate proportional hazards models, history of treatment for depression was significantly associated with subsequent myocardial infarction (hazard ratio = 2.10, confidence interval = 1.04-4.23).

CONCLUSIONS

A self-reported history of treatment for depression is independently associated with subsequent myocardial infarction in treated hypertensive patients without prior cardiovascular disease. Whether additional or different treatment for depression will be cardioprotective is unknown and merits further study.

Carbon isotopic ratios of atmospheric CO(2) affect the delta(13)C values of heterotrophic growth in Nicotiana tabacum

Heterotrophic Nicotiana tabacum (L. CV. Wisconsin 38) plants are enriched in 13C relative to the carbon sources in their growth medium. We examined whether carboxylation via phosphoenolpyruvate carboxylase contributes to the enrichment. Achlorophyllous plants were produced using an inhibitor of carotenoid synthesis and were grown on sucrose with known delta(13)C values. Groups of plants were exposed to air with different delta(13)C values as well as to CO(2)-free air. The delta(13)C values of heterotrophic plants were greater than the sucrose source in all treatments and this enrichment increased as 13CO(2)/12CO(2) ratios increased in the source air. Rubisco activity was ruled out as a cause for the enrichment observed as 13CO(2)/12CO(2) ratios increased because the delta(13)C values of heterotrophic plants were similar when exposed to high 13CO(2) while grown in the light or dark. Neither was enrichment due to the adsorption of 13CO(2) in the high 13CO(2) treatment because dead plants did not exhibit this effect when subjected to the same atmospheric treatments. Carboxylation by PEP carboxylase is a likely mechanism causing the 13C-enriched values of living white tissues relative to their organic carbon sources. These results experimentally support suggestions that the anaplerotic activity of PEP is responsible for the 13C-enrichment commonly observed where heterotrophic inputs to growth are large such as in very young leaves.

Serum potassium and cardiovascular mortality

BACKGROUND

The impact of serum potassium on mortality is inadequately defined.

OBJECTIVE

To determine the association of serum potassium with mortality.

METHODS

We analyzed NHANES I Epidemiological Follow-up Study data from 1974-1992. Of 2,992 subjects with baseline serum potassium, 156 were excluded because their vital status was not known. A total of 2,836 subjects with serum potassium within 2.7-5.4 mmol/L were studied. All-cause and cardiovascular mortality were assessed controlling for sociodemographic status, smoking, medical history, and clinical characteristics.

RESULTS

At baseline, mean age was 46.6 years, and mean serum potassium was 4.07 mmol/L. Subjects were stratified into three groups by mean +/-1 standard deviation of serum potassium: low, 2.7-3.7 mmol/L (N = 477); middle, 3.8-4.4 mmol/L (N = 1,982); and high, 4.5-5.4 mmol/L (N = 377). The cardiovascular mortality rate per 1,000 person-years adjusted for age, gender, and race for the high serum potassium group (8.1) was significantly higher than the middle (5.3) and low (6.5) serum potassium groups. Further analysis, controlling for age, gender, race, smoking status, cholesterol, and history of diabetes, renal disease, and cardiovascular disease, revealed that the increased cardiovascular mortality among subjects with moderately increased serum potassium was most prominent in those reporting use of diuretics (hazard ratio, 2.65; 95% confidence interval [95% CI], 1.20 to 5.85) and those with abnormal renal function (hazard ratio, 1.89; 95% CI, 1.05 to 3.41).

CONCLUSION

In this general population sample with mostly normal serum potassium, higher serum potassium was independently associated with increased cardiovascular mortality.

Maternal mortality in New York City: excess mortality of black women

To assess maternal mortality in New York City, birth certificates and mortality records for New York City from 1988 through 1994 were linked and examined. During these 7 years, maternal mortality in New York City (defined by the International Classification of Diseases, 9th edition [ICD-9], as 630-676) per 100,000 live births significantly exceeded that of the country as a whole (20.2 vs. 8.2, respectively). Within New York City, an even greater variation of maternal mortality by race/ethnicity was noted, with the mortality ratio of whites, blacks, and Hispanics being 7.1, 39.5, and 14.4 per 100,000 live births, respectively. Socioeconomic characteristics such as educational attainment, marital status, and income influenced maternal mortality more in non-blacks than blacks. Analyses of cause-specific mortality revealed that, overall, ectopic pregnancy, embolism, and hypertension were the leading causes of death. However, the major factors explaining the excess maternal mortality among blacks were hypertension (mortality ratio of blacks to whites 5.57, 95% confidence interval 2.30-13.39), ectopic pregnancy (4.78, 95% confidence interval 2.40-9.51), and abortion (4.58, 95% confidence interval 1.72-12.22). These findings confirm a persisting gap in maternal death between black and white women. Indeed, if all New Yorkers who became pregnant enjoyed the survival of the city's non-Hispanic white residents, the difference in maternal mortality between the city and the nation would be eliminated.

Dietary potassium intake and stroke mortality

BACKGROUND AND PURPOSE

An inverse relationship of dietary potassium to stroke mortality in a small community has been previously reported. To further assess this association in a larger sample, we examined data from the first National Health and Nutrition Examination Survey (NHANES I) Epidemiological Follow-up Study.

METHODS

We analyzed baseline data during 1971-1975 and follow-up through 1992. Dietary potassium intake, determined by 24-hour dietary recall at baseline, was available for 9866 subjects. Stroke mortality was recorded through 1992 follow-up.

RESULTS

Mean age and dietary potassium at baseline were 55 years and 2084 mg/d; blacks reported significantly lower potassium intake than whites (1606 versus 2178 mg/24 h). During an average of 16.7 years of follow-up, there were 304 stroke deaths. For men, stratified by tertile of dietary potassium intake, age-adjusted stroke mortality rates per 1000 person-years for the lowest dietary potassium group were significantly higher than for the highest intake group, for both whites (1.94 versus 1.17; relative risk, 1.66; 95% CI, 1.32 to 2.14) and blacks (5.08 versus 1.19; relative risk, 4.27; 95% CI, 1.88 to 9. 19). For women, there was no significant difference in stroke mortality between similar levels of potassium intake for either whites (1.61 versus 1.42; relative risk, 1.13; 95% CI, 0.84 to 1.66) or blacks (2.46 versus 3.04; relative risk, 0.80; 95% CI, 0.21 to 2. 01). After stratification by hypertensive status, stroke mortality rates were significantly different by tertile of dietary potassium only for hypertensive men. There was no stroke mortality difference by potassium intake among hypertensive women or nonhypertensive men and women. Multivariate analysis, in which we controlled for caloric intake and other baseline cardiovascular risk factors, revealed that only among black men and hypertensive men was lower dietary potassium intake a predictor of stroke mortality.

CONCLUSIONS

The previous finding of an association of increasing dietary potassium intake with decreasing stroke mortality has been detected only among black men and hypertensive men in this study.

Assessing managed care's role in promoting preventive care

The current trend of managed health care systems opens the door to more effective control of chronic diseases through preventive care. The goal of this study was to assess managed care's role in promoting preventive care. A mail survey was conducted of a national sample of 1,200 directors, associated with preventive care, in managed care organizations (MCOs) in the U.S. Data was obtained on perceived effectiveness, degree of importance, and likelihood of support for implementation of strategies recommended (case management, utilization review programs, selective contracting, and cost sharing) for ensuring appropriate utilization of preventive services. Also, information was collected on interventions perceived effective in encouraging plan members to utilize and providers to offer preventive services. Response rate was 17.3%. Case management and prospective and concurrent utilization review programs were perceived most effective, important, and likely to receive support for implementation while cost sharing (using deductibles and coinsurance) and retrospective utilization review programs ranked low on all dimensions. Plan member-directed interventions perceived effective in encouraging utilization of preventive services included telephone and mail reminders while computer-generated reminders and medical record audits with feedback were perceived effective in encouraging providers to offer such services. Results identified preferred MCO strategies and interventions for ensuring appropriate utilization of preventive services. Further research is needed to develop methods to encourage people at high risk for chronic diseases not currently utilizing preventive services to receive such services.

Prevention of renal ischemia-reperfusion-induced injury in rats by picroliv

Picroliv is a potent antioxidant extracted from the roots and rhizome of Picrorhiza kurrooa. It has been shown to impart significant hepatoprotective activities, partly by modulation of free radical-induced lipid peroxidation. Lipid peroxidation and reactive oxygen species are associated with tissue injury in post-ischemic acute renal failure. The efficacy of picroliv was assessed in an in vivo model of renal ischemia-reperfusion injury (IRI) in rats at a dose of 12 mg/kg orally for 7 days. The animals were killed at various times after reperfusion. Increased lipid peroxidation and apoptotic cell number reflected the oxidative damage following renal IRI. Picroliv-pretreated rats exhibited lower lipid peroxidation, improved antioxidant status, and reduced apoptosis, indicating better viability of renal cells. Immunohistochemical studies revealed that picroliv pretreatment attenuated the expression of intercellular adhesion molecule-1 in the glomerular region. These results suggested that picroliv pretreatment protects rat kidneys from IRI, perhaps by modulation of free radical damage and adhesion molecules.

Myocardial infarction in treated hypertensive patients: the paradox of lower incidence but higher mortality in young blacks compared with whites

BACKGROUND

Despite the impressive decline in coronary heart disease death rates, a mortality differential between blacks and whites persists. Our study objective was to determine whether excess mortality among well-controlled hypertensive black men compared with whites is due to differences in disease incidence or in case fatality.

METHODS AND RESULTS

Of 3382 male subjects (1266 blacks and 2116 whites) enrolled between 1973 and 1996 and followed up through 1997 in a work-site hypertension control program, 2343 were followed up until 60 years of age, and 1884 were followed up until >60 years of age (either continuing after 60 years [n=845] or beginning treatment at >/=60 years [n=1039]), with a mean follow-up of 5.2 and 5.5 years, respectively. During follow-up, 186 myocardial infarction (MI) events (including 31 revascularizations) occurred, with 63 in patients <60 years and 123 in patients >/=60 years of age. Age-adjusted MI incidence was nearly twice as high for whites as blacks in younger (6.3 versus 3.4/1000 person-years) and older (14.1 versus 7.5 person-years) subjects. In contrast, the age-adjusted case fatality rate was 3-fold higher for younger blacks than for whites (37.8% versus 12.2%). In older patients, case fatality did not differ significantly between blacks and whites (37.6% versus 50. 3%). In separate Cox regression analyses, among younger blacks but not younger whites, history of diabetes and smoking were significantly associated with both incidence and fatality.

CONCLUSIONS

In these treated male hypertensive patients with good blood pressure control (139.6/85.7 mm Hg), young blacks, despite a lower MI incidence, had higher MI mortality than did their white counterparts. Their higher case fatality rate was associated with fewer coronary artery revascularizations and a higher prevalence of diabetes and smoking.

Tunicamycin enhances the anticellular activity of interferon by inhibiting G1/S phase progression in 3T3 cells

We have shown earlier that the cell growth inhibitory activity of interferon (IFN) is significantly enhanced by tunicamycin (TM) (Maheshwari et al., Science 219, 1339-1341, 1983). In this report, we investigated various regulatory points of synergistic action between TM and IFN-alpha/beta that inhibit cell growth in NIH 3T3 cells. The MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) viability assays showed a dose-dependent increase in percentage inhibition of the cells when treated with either TM or IFN. When doses of TM and IFN that had no significant inhibition on cell viability were used in combination, there was a pronounced suppression of DNA synthesis (tritiated thymidine incorporation). Flow cytometry studies revealed that individual treatments with either IFN or TM that did not alter the cell cycle profile, when combined, resulted in an impaired cell cycle by inhibiting G1/S progression. The blockage of G1/S transition was associated with reduction of cyclin-dependent kinase (CDK4) activity. The mRNA (analyzed by ribonuclease protection assay) and protein levels (assayed by Western blotting) of cyclins D1, D3, and CDK4 were downregulated by combined treatment with IFN and TM. An increase in the expression of p27/kipl, an inhibitor of CDK4, was observed in cells that were treated with both IFN and TM. These studies suggest that insufficient formation of the active cyclin/CDK complex could possibly be deferring the cells from normal cycling and may be responsible for the ability of TM to enhance cell growth inhibition induced by IFN.