Identification of PLC210, a Caenorhabditis elegans phospholipase C, as a putative effector of Ras

Mammalian Ras proteins regulate multiple effectors including Raf, Ral guanine nucleotide dissociation stimulator (RalGDS), and phosphoinositide 3-kinase. In the nematode Caenorhabditis elegans, LIN-45 Raf has been identified by genetic analyses as an effector of LET-60 Ras. To search for other effectors in C. elegans, we performed a yeast two-hybrid screening for LET-60-binding proteins. The screening identified two cDNA clones encoding a phosphoinositide-specific phospholipase C (PI-PLC) with a predicted molecular mass of 210 kDa, designated PLC210. PLC210 possesses two additional functional domains unseen in any known PI-PLCs. One is the C-terminal Ras-associating domain bearing a structural homology with those of RalGDS and AF-6. This domain, which could be narrowed down to 100 amino acid residues, associated in vitro with human Ha-Ras in a GTP-dependent manner and competed with yeast adenylyl cyclase for binding Ha-Ras. The binding was abolished by specific mutations within the effector region of Ha-Ras. The other functional domain is the N-terminal CDC25-like domain, which possesses a structural homology to guanine nucleotide exchange proteins for Ras. These results strongly suggest that PLC210 belongs to a novel class of PI-PLC, which is a putative effector of Ras.

The relation between income and mortality in U.S. blacks and whites

Differential mortality exists in the United States both between racial/ethnic groups and along gradients of socioeconomic status. The specification of statistical models for processes underlying these observed disparities has been hindered by the fact that social and economic quantities are distributed in a highly nonrandom manner throughout the population. We sought to provide a substantive foundation for model development by representing the shape of the income-mortality relation by racial/ethnic group. We used data on black and white men and women from the longitudinal component of the National Health Interview Survey (NHIS), 1986-1990, which provided 1,191,824 person-years of follow-up and 12,165 mortal events. To account for family size when considering income, we used the ratio of annual family income to the federal poverty line for a family of similar composition. To avoid unnecessary categorizations and prior assumptions about model form, we employed kernel smoothing techniques and calculated the continuous mortality surface across dimensions of adjusted income and age for each of the gender and racial/ethnic groups. Representing regions of equal mortality density with contour plots, we observed interactions that need to be accommodated by any subsequent statistical models. We propose two general theories that provide a foundation for more elaborate and testable hypotheses in the future.

Mortality patterns among adult Hispanics: findings from the NHIS, 1986 to 1990

OBJECTIVES

The purpose of this study was to assess the mortality pattern of the adult Hispanic population in the United States.

METHODS

This was a cohort study using data from the National Health Interview Survey from 1986 through 1990. Deaths were ascertained by matching the National Death Index through 1991.

RESULTS

This representative national sample included 297,640 non-Hispanic Whites, 53,552 Blacks, and 27,239 Hispanics, all aged 18 years or older at baseline. Different matching criteria resulted in modest differential estimates of the number of deaths by ethnic groups; these differences were quantitatively more important for Hispanics. Overall age-standardized mortality was lower among Hispanics. A prominent age by race interaction was apparent. The Hispanic: White mortality ratio was 1.33, 0.92, and 0.76 among men aged 18 through 44, 45 through 64, and 65 and older, respectively. Among women in the same age groups the Hispanic: White mortality ratio was 1.22, 0.75, and 0.70, respectively.

CONCLUSIONS

Longitudinal cohorts provide an important source of health status information on Hispanics. These results suggest that overall mortality is lower among Hispanics than among non-Hispanic Whites, especially in the oldest age group. Among younger and middle-aged persons, the mortality of Hispanics is similar to or even higher than that of Whites.

Synthesis and pharmacological evaluation of triflate-substituted analogues of clozapine: identification of a novel atypical neuroleptic

The trifluoromethanesulfonyloxy (TfO) analogues 3 and 4 of 8-chloro-11-(4-methyl-1-piperazinyl)-5H-dibenzo[b,e][1,4]diazepine (clozapine, 1) and its 2-chloro isomer (iso-clozapine, 2), respectively, were synthesized via their OMe and OH analogues with the conventional synthetic method of the tricyclic dibenzodiazepines and evaluated pharmacologically along with their parent drugs. The binding profile of the 2-OTf analogue (4) is comparable to the binding profile of 1, although the affinity for the dopamine (DA) D2 receptors is higher (IC50 values are 31 nM and 330 nM for compounds 4 and 1, respectively). Interestingly, no notable affinity for muscarinic receptors could be detected in compound 4. On the contrary, the 8-OTf analogue 3 only displayed affinity for muscarinic M1 receptors (IC50 value 35 nM) and no affinity (IC50 value > 500 nM) for the other receptors tested. The 10 mumol/kg sc dose, but not the 10 mumol/kg po dose, of compound 4 stimulated the output of DA. Increases of 80% and 35% in DOPAC output from the dorsal striatum were seen after sc and po administrations of 10 mumol/kg of compound 4, respectively. Doses up to 100 mumol/kg of compound 3 had no effect on either parameter. Doses up to 100 mumol/kg of compound 4 were not cataleptogenic, but significantly decreased apomorphine-induced locomotor activity. In conclusion, compound 4 (GMC1-169) is a new clozapine-like neuroleptic candidate, which is lacking anticholinergic properties and displays a higher potency, as compared to clozapine (1) itself.

[Analysis of the pyridinoline and deoxypyridinoline in urine by reversed-phase high performance liquid chromatography (RP-HPLC)]

A method for the simultaneous and rapid determination of pyridinoline and deoxypyridinoline in urine using RP-HPLC has been established. After hydrolysis for 18 hours at 107 degrees C in 6 mol/L HCl, the urine sample was prefractionated by partition chromatography using a column packed with cellulose CF1. The appropriate fractions were freeze-dried. The samples were analyzed by HPLC with a 5 microm Spherisorb C18 column, a mobile phase of MeOH/H2O containing 0.1% heptafluorobutyric acid at a rate of 1.2 mL/min and fluorescence detector monitoring at lambda(ex) 290 nm and lambda(em) 400 nm. The limit of a detection for PYD was 10 nmol/L and DPD 7 nmol/L. The recovery of PYD was 91.5% and that of DPD was 106.1%. Within day CV for the two compounds were 1.39% and 0.16% respectively and day-to-day CV 3.71% and 1.32% respectively.

Mortality from coronary heart disease and cardiovascular disease among adult U.S. Hispanics: findings from the National Health Interview Survey (1986 to 1994)

OBJECTIVES

We sought to estimate the coronary heart disease (CHD) and cardiovascular disease (CVD) mortality experience of U.S. Hispanics.

BACKGROUND

Limited information is available concerning the mortality from CHD among U.S. Hispanics, the nation's second largest minority group.

METHODS

The study used data from the National Health Interview Survey (1986 to 1994), including representative national samples of 246,239 non-Hispanic whites, 38,042 blacks and 14,965 Hispanics who were > or = 45 years old at baseline. Mean follow-up of mortality was 5 years (range 1 to 10).

RESULTS

During the follow-up period, 27,702 whites (11%), 4,976 blacks (13%) and 1,061 Hispanics (7%) died. Among men, the age-adjusted total mortality per 100,000 person-years was 3,089 in whites and 2,466 in Hispanics, and among women, it was 1,897 and 1,581 in whites and Hispanics, respectively. The Hispanic/white mortality rate ratio for CHD was 0.77 (95% confidence interval [CI] 0.64 to 0.93) and 0.82 (95% CI 0.66 to 1.01) for men and women, respectively. The rate ratio was 0.79 (95% CI 0.68 to 0.91) and 0.80 (95% CI 0.69 to 0.94), respectively, for mortality from cardiovascular diseases. Given the lower all-cause mortality in Hispanics, the proportion of total deaths due to CHD and CVD was similar between the two populations for the same gender and were, respectively, 29.7% and 44.7% in white men, 28.1% and 44.3% in Hispanic men, 24.9% and 43.2% in white women and 24.1% and 41% in Hispanic women.

CONCLUSIONS

These data from a cohort of a large national sample are consistent with vital statistics that show that all-cause, CHD and CVD mortality is approximately 20% lower among adult Hispanics than among whites in the United States.

Polarization characteristics of a Nd:YAG laser side pumped by diode laser bars

A detailed experimental investigation of the polarization characteristics of a diode laser side-pumped Nd:YAG laser has been performed. A Brewster plate inserted into the cavity resulted in a decrease of 50% of the output power that is due to depolarization. A thin-film polarizer (TFP) was introduced into the cavity and the depolarization loss served as the output coupling. By introduction of a quarter-wave plate (QWP) the output coupling rate and the beam shape were improved. An analytical expression for the output coupling rate of a cavity containing a TFP and a QWP has been derived. The experimental results are in good agreement with the simplified theoretical analysis.

Highly efficient diode-stack, end-pumped Nd:YAG slab laser with symmetrized beam quality

An efficient high-power cw Nd:YAG slab laser, partially end pumped by diode-laser stacks, and a novel beam-shaping technique are reported. The optical efficiency amounted to 44 %, and the slope efficiency amounted to 55 %. Introducing an intracavity Brewster plate to polarize the laser beam, we obtained an optical efficiency of 35 % and a slope efficiency of 41 %. The output beam was rectangular and the beam quality asymmetric in two orthogonal directions. To equalize the beam quality, we introduced a step-mirror beam-shaping technique. The beam-shaping technique and the results obtained are discussed.

[The preliminary study on WCMM machinable glass-ceramics]

The aim of this work was to investigate machinable glass-ceramics used as oral restoration material in K2O-MgO-Al2O3-SiO2-F glass system. By using of DTA, XRD and SEM investigation, the crystalline structure and characteristics were tested. The chemical composition of WCMM machinable glass-ceramics was defined by the following general formula: (K,Na)Mg3-3x Al2x (AlSi3) O10F2(0.5 < or = x < 0.7). The experimental results show that WCMM is an excellent oral restoration materials in the fabrication of crowns, inlayers and veneers.

Relative weight and mortality in U.S. blacks and whites: findings from representative national population samples

PURPOSE

To examine the impact of relative weight on mortality in black and white men and women.

METHODS

Two representative national populations samples were used: the NHANES-I Epidemiologic Follow-up Study (NHEFS), and the National Health Interview Survey (NHIS). The principal analysis focused on 13,242 participants in the NHEFS and 114,954 in the NHIS. Minimum mortality was estimated from both categorical analysis and a logistic model.

RESULTS

Minimum mortality ranged from a body mass index (BMI) of 25 to 32 kg/m2. The model-estimated BMI of minimum mortality for NHEFS was 27.1 (24.8-29.4, 95% CI), 26.8 (24.7-28.9, 95% CI), 24.8 (23.8-25.9, 95% CI) and 24.3 (23.2-25.4, 95% CI); for black men, black women, white men and white women, respectively, whereas for NHIS the corresponding values were 30.2 (24.8-35.6, 95% CI) 26.4 (24.2-28.7, 95% CI), 27.1 (25.5-28.7, 95% CI), and 25.6 (24.2-27.0, 95% CI). In all groups the shape of the relative risk curve was virtually identical and a broad range of BMI values in the middle of the distribution was associated with low relative mortality risk. Averaging the results from both surveys, the observed BMI of minimum risk was 3.1 kg/m2 higher in black men and 1.5 kg/m2 higher in black women than in their white counterparts; when adjusted for covariates these differences were only of borderline statistical significance, however.

CONCLUSIONS

Because of the wide range of BMI values associated with low risk, and the consistency of the point of the up-turn in risk, group specific definitions of optimal values do not appear to be warranted.

Rapid detection of Mycoplasma pneumoniae by an assay based on PCR and probe hybridization in a nonradioactive microwell plate format

A new molecular assay, based on a rapid DNA extraction protocol, PCR, and hybridization to a specific probe in a nonradioactive microwell plate format was used to detect Mycoplasma pneumoniae in bronchoalveolar fluid specimens. The sensitivity of the assay was determined to be 10 to 100 organisms with M. pneumoniae reference strains. Specificity testing with different bacteria capable of producing pneumonia showed no cross-reactivity. In a prospective study, bronchoalveolar lavage fluids obtained from patients with pneumonia were investigated with the PCR assay and compared to culture. Twelve positive samples were detected with the PCR assay. Seven of them were subsequently confirmed by culture. All patients with positive PCR results seroconverted. Application of the PCR assay described may lead to safe and early diagnosis of M. pneumoniae in patients with pneumonia.

[The crystallization feature of a castable apatite glass-ceramics]

The crystallization feature of a castable apatite glass-ceramics was studied by the means of DTA, XRD and SEM. The effect of chemical composition on the microsturcture of the glass-ceramics was discussed. The introduction of MgO and Al2O3 into the system has a substantial influence on the crystallization feature.

Dynamics and stability of a laser system with second-order nonlinearity

We use a multimode rate-equation model to investigate the stability of a laser system with second-order nonlinearity and compare the results with the literature on intracavity frequency-doubled lasers. The emphasis is on the Hopf bifurcation between the asymptotically stable state and the stable oscillation that occurs with variation of the conversion efficiency from the fundamental frequencies to their sum. This bifurcation results in two simple expressions that describe the stability curve, depending on material and cavity parameters. We also report on an experimental confirmation of the predicted temporal behavior of sum-frequency generation.

[The study on apatite castable glass-ceramics in composition and physicochemical properties]

The authors reported the result of the study of the glass formation range and physicochemical characteristics of apatite (APA) castable ceramics in the CaO-MgO-Al2O3-SiO2-P2O5 system. The relationship between its component and casting properties, the mechanical property and chemical stability was mainly discussed. The result showed that homogeneous glass could be formed in the experimental scope. This glass crystallized enamel-analogous apatite phase. It has improved mechanical property of parent glass, the bending strength was up to 165 MPa and possessed a fine chemical stability. This investigation could provide a new castable ceramics material for dental restoration.

Prediction of mortality risk by different methods of indexation for left ventricular mass

OBJECTIVES

We sought to compare the predictive value of echocardiographically determined left ventricular hypertrophy on death from all causes and cardiac mortality using various methods of indexation for left ventricular mass.

BACKGROUND

Considerable controversy exists regarding the optimal method for indexing left ventricular mass to body size in the clinical setting.

METHODS

The study included 988 consecutive patients who had both coronary angiograms and echocardiographic examinations in an inner-city public hospital in Chicago, Illinois. Patients were followed up for a mean of 7 years (range 2 to 11).

RESULTS

Various left ventricular mass indexes (e.g., mass indexed for height, height2, height2.13, height2.7, body surface area and body surface area1.5 were highly correlated (r = 0.90 to 0.99). Used as a continuous measure, an increase in any left ventricular mass index was associated with similar risk of death from all causes and cardiac diseases. Although left ventricular hypertrophy assessed by mass indexed for body surface area using the published conventional partition values provided somewhat better prediction, the adjusted relative risk was in general not significantly different from hypertrophy based on other indexes. Patients with left ventricular hypertrophy defined concordantly by indexes based on both body surface area and height (or height2.7) had, by definition, the highest average mass indexes among all groups and experienced as much as a threefold greater risk of death than those without hypertrophy. A small proportion of patients (12%) who were classified into the hypertrophy group by height-based indexes alone, but not by body surface area, had a moderate increase in mass and showed no increase in risk, even though being overweight was extremely prevalent in this group.

CONCLUSIONS

Because of the high correlation among various body size indexes, left ventricular hypertrophy, defined by different indexes for left ventricular mass, similarly confers increased risk of mortality in patients with or without coronary artery disease.

Performance of the automated COBAS AMPLICOR system for the detection of hepatitis C virus RNA

BACKGROUND

The COBAS AMPLICOR (CA) instrument for the amplification and detection steps of the AMPLICOR molecular diagnostic assays has recently been introduced. The system contains a single thermal cycler with two independently controlled heating/cooling blocks, a pipettor, a magnetic particle washer, a photometer and an incubator.

OBJECTIVE

The performance of the CA instrument was evaluated in a routine diagnostic laboratory for the detection of hepatitis C virus (HCV) RNA. The new system was compared with the corresponding microwell plate assay (AMPLICOR HCV Test).

STUDY DESIGN

Routine clinical sera (350) from hemodialysis patients and patients with chronic HCV infection and interferon therapy were studied. If discrepant results were obtained, both assays were repeated (specimen preparation, amplification and detection); in addition, the HCV copy number was determined with the AMPLICOR HCV MONITOR Test.

RESULTS

There was a correlation between the CA HCV Test and the AMPLICOR HCV Test in 341 of 350 specimens (97%). After resolution of 9 discrepant results, the CA HCV Test gave a sensitivity of 97.8% and a specificity of 99.4%. The most common reason for discrepant results was a low HCV RNA copy number.

CONCLUSION

The CA system was found to be a labor-saving, fast and reliable instrument for the amplification and detection steps of a RT-PCR molecular assay for detection of HCV RNA.

[Mechanism of protective action of Phyllanthus urinaria L. against injuries of liver cells]

It has been found out that the carbon tetrachloride (CCl4)-induced increase of serum glutamic-pyruvic transaminase (ALT) and elevation of MDA in liver of mice are significantly lowered by Phyllanthus urinaria in vivo, and the coincubation of isolated rat hepatocytes with Phyllanthus urinaria in vitro significantly inhibits CCl4-induced decrease of mobility of membrane of liver cells and increase of intracellular free Ca2+ ([Ca2+]i) concentrations of liver cells. These results suggest that the anti-lipid peroxidation effect and protective action of membrane of Phyllanthus urinaria may be related to its protective action against CCl4-induced liver injuries.

Effect of aspirin on prostaglandin E2 and leukotriene B4 production in human colonic mucosa from cancer patients

Results from epidemiological studies indicate that chronic administration of aspirin reduces the incidence of colon cancer. The mechanism that accounts for this reduction is not known, but it may be related to the decreased production of prostanoids that results from aspirin inhibition of cyclooxygenase. However, it is not known whether aspirin has a local effect on prostanoid production in the colonic mucosa and whether this effect is dose dependent. In this study, we determined the effect of oral administration of aspirin on the production of the prostanoid prostaglandin E2 (PGE2) in the intact human colonic mucosa. Inhibition of cyclooxygenase could result in an increased availability of arachidonic acid and a corresponding increase in production of other eicosanoids. To determine whether such an effect occurs, we also quantitated the concentration of leukotriene B4 (LTB4) in colonic mucosal samples. Mucosal samples were obtained during sigmoidoscopy from the colons of 17 subjects with a history of colonic cancer prior to and following 60 days of self-administration of 325 mg aspirin/day and again 60 days after administration of 650 mg aspirin/day. PGE2 and LTB4 concentrations were determined by enzyme immunoassay for tissue samples that were flash frozen after removal from the biopsy forceps and also in medium that was collected from tissue samples that were incubated for 4 h following removal from the subject. PGE2 concentrations were decreased significantly in samples collected after 60 days of consumption of 325 mg aspirin. An additional 60 days of consuming 650 mg aspirin/day did not result in a further significant decrease relative to that attained after consumption of 325 mg/day. Similar results were obtained using colonic explants, and the addition of aspirin to medium further reduced PGE2 production. LTB4 in tissue and medium was not significantly different in pre-versus post-aspirin samples, with the exception of an increased concentration in medium samples collected after consumption of 650 mg/day relative to pre-aspirin samples. The results indicate that aspirin affects eicosanoid production in the colonic mucosa of humans, but the effect is most likely restricted to products of the cyclooxygenase-dependent pathway. It appears that 325 mg of aspirin is sufficient to affect PGE2 production and that increasing the dosage to 650 mg daily provides an additional decrease in PGE2 synthesis. However, the higher dosage was associated with a considerable increase in complaints of gastric discomfort. Additional study is needed to establish whether doses less than 325 mg also provide a significant decrease in PGE2 production.

Selective reporter expression in mast cells using a chymase promoter

Primate alpha-chymases are mast cell neutral proteases that are involved in regulating several regulatory peptides including angiotensin II. Because of significant substrate specificity differences among the chymase group of enzymes, animal models that overexpress primate chymases are crucial for delineating the in vivo function of these enzymes. Activation of alpha-prochymase requires processing enzymes and proteoglycans found in mast cell secretory granules. Thus, the development of models overexpressing active primate chymase requires a mast cell-specific promoter. We show that the 571-base pair (bp) 5'-upstream sequence of the baboon chymase gene, which encodes an alpha-chymase, coupled to the prokaryotic lacZ gene allows the targeting of beta-galactosidase to mast cells in transgenic mice. Tissue expression of the transgene is similar to the expression of the endogenous mouse alpha-chymase mouse mast cell protease-5. A mouse mast cell line that endogenously expresses mouse mast cell protease-5 (JKras mast cells) also selectively supports the expression of this transgene. In vitro transcription studies in JKras mast cells shows the critical role of a GATA cis-regulatory motif in baboon chymase promoter, located approximately 430-bp upstream of the transcription start site. These results suggest that the 571-bp domain of the baboon chymase promoter contains most, if not all, of the mast cell-specific region of the promoter. We describe here for the first time a promoter that directs expression of transgenes specifically to mouse mast cells. This promoter should be generally applicable for dominant expression of mast cell regulatory proteins.

Apoptosis of human BEL-7402 hepatocellular carcinoma cells released by antisense H-ras DNA--in vitro and in vivo studies

Recent findings suggest that over-expression of activated H-ras inhibited apoptotic cell death by blocking the activity of apoptotic endonuclease(s). This study was designed using antisense H-ras oligodeoxynucleotides (ODN) to evaluate whether alterations of H-ras expression in BEL-7402 human hepatocellular carcinoma cells could influence the induction of apoptosis in vitro and in vivo. We found that, in vitro, continuous suppression of H-ras expression could decrease the proliferation of BEL-7402 cells and inhibit H-ras-induced entry into S phase. In situ end labeling showed that a large number of cells underwent apoptotic cell death after treatment with antisense H-ras ODN (P < 0.01), and gel electrophoresis of DNA extracted from these cells demonstrated a typical DNA ladder, characteristic of apoptosis. In vivo study indicated that pretreatment with antisense H-ras significantly retarded tumor growth in comparison with the untreated controls or tumors treated with non-specific ODN (P < 0.01, P < 0.01). In situ end-labeling revealed that pronounced apoptotic nuclei were also present in the tissue treated with antisense H-ras ODN (P < 0.01). Immunocyto-histochemical study showed that expression of p21H-ras was significantly decreased after treatment with antisense H-ras. These results indicate that suppression of H-ras over-expression by antisense ODN could effectively inhibit tumor growth and revive the apoptotic pathway by releasing the activity of apoptotic endonuclease(s). The data also suggest the need for further studies to elucidate molecular events involved in antisense H-ras-released apoptosis and evaluate its therapeutic implications.

Mechanism of anti-beta-adrenoceptor antibody mediated myocardial damage in dilated cardiomyopathy

Antibodies against beta(1)-adrenoceptor can be detected in serum of patients with dilated cardiomyopathy (DCM), which have beta-agonist-like activity, and induce a positive chronotropic effect on cardiac myocytes by its persistence at full strength. Effects of the antibodies against beta-adrenoceptor from sera of patients with DCM on myocardial cytotoxicity and cytoplasmic free Ca(2+)-concentration ([Ca2+]i) were observed in the cultured single layer SD rat ventricular cells by using the cytotoxicity assay and fluorescent Ca(2+)-indicator fura-2/AM. The positive sera of the anti-beta-adrenoceptor antibodies from patients with DCM markedly enhanced myocardial [Ca2+]i. Betaloc, a beta(1)-receptor blocker, might inhibit the increase of the antibody-mediated myocardial [Ca2+]i, and the sera from healthy donors had no effect on myocardial [Ca2+]i. Our results suggest that the anti-beta-adrenoceptor antibody might increase myocardial [Ca2+]i and result in myocardial damage. The antibodies might activate receptor-gating Ca(2+)-channel, thereby causing myocardial [Ca2+]i rise and calcium overload. Early use of betaloc is recommended in the treatment of dilated cardiomyopathy.

Patterns of comorbidity and mortality risk in blacks and whites

Comorbidity, the co-existence of multiple chronic conditions in a single individual, has been shown to modify the prognosis of disease states. To estimate disease burdens within and among racial subpopulations of the United States, we examined cross-sectional patterns of comorbidity and their impact on survival using data from the NHANES-1 Epidemiologic Follow-up Study (NHEFS). We considered the occurrence of four cardiovascular conditions: stroke, coronary heart disease, hypertension and diabetes. We summarize the joint occurrence of these four conditions using these different methodologies: the number of conditions occurring in each individual and two summaries that weight the conditions according to their prognostic significance. Using all three methodologies, we found an excess burden of chronic disease in black women as compared with white women. Black men had an excess burden compared to white men for the first two methodologies. However, when we model the relationship of the joint occurrence of the conditions to subsequent mortality, black men and white men are seen to have a similar burden. This similarity of black and white men is due to an interaction between race and prevalent stroke in men that we hypothesize may be due to the small number of black men available for study. Given the apparent conditioning effect of co-existing diseases, it is evident that estimation of disease burdens among groups that differ in terms of health status, in particular among U.S. blacks and whites, requires accounting for the occurrence of multiple chronic diseases. Using either the number of conditions or the prognosis weighted summary, we demonstrated a higher burden of the conditions considered in blacks that in whites in a sample of the U.S. population.

[The effect of antisense H-ras on growth and metastasis of a high metastatic tumor model of human hepatoma in nude mice LCI-D20]

OBJECTIVE

To investigate if treatment with antisense H-ras oligodeoxynucleotides (ODNs) modulates tumor growth, apoptosis and metastasis of a high metastatic tumor model of human hepatocellular carcinoma (HCC) in nude mice LCI-D20, in which over-expression of H-ras has been identified.

METHODS

LCI-D20 cells in primary culture were treated with 10 mumol/L antisense ODNs in vitro. 1.5 x 10(6) LCI-D20 cells with or without pretreatment were inoculated into each elevated subcutaneous (s.c) flap in fourteen nude mice, 6 animals for antisense H-ras ODN treated cells, 4 for H-ras non-specific antisense ODN treated cells, the rest 4 for cells without pretreatment.

RESULTS

In in vitro cell culture study, 5-day continuous suppression of H-ras expression by antisense H-ras ODNs resulted in significant inhibition of the proliferation of LCI-D20 cells (t = 31.529, P < 0.01). Cell cycle analysis showed a significant decrease in S phase (36.0 +/- 1.4) and a remarkable increase in G1/G0 fraction (56.7 +/- 1.1) after exposure to antisense H-ras ODNs in comparison with the cells without any treatment (58.5 +/- 0.9, t = 13.519, P < 0.01, 37.4 +/- 0.7, t = 14.802, P < 0.01). In situ end-labeling (ISEL) detection showed that apoptotic cell death was significantly increased in cells with 5-day treatment of antisense H-ras ODNs (34.0% +/- 4.5%) in comparing with cells without treatment (2.5% +/- 1.2%, t = 13. 434, P < 0.01) or treated with non-specific antisense ODNs (4.8% +/- 1.4%, t = 12.453, P < 0.01) at the corresponding time. In in vivo experiment, after six-week observation, tumor growth in antisense H-ras treated animals was significantly retarded in comparison with that of the untreated (t = 3.509, P < 0.01) or nonspecific antisense ODN treated animals (t = 3.452, P < 0.01).

CONCLUSIONS

Specific inhibition of H-ras expression by antisense H-ras ODNs could not only induce apoptotic cell death, inhibit the growth rate of LCI-D20 cells in vitro and in vivo, but also alter in vivo tumorigenesity and metastatic potential of LCI-D20 cells.

[The relationship between human chorionic gonadotrophin and lipoprotein metabolism]

We compared human chorionic gonadotrophin (hCG-beta) with lipids, lipoproteins and apolipoproteins in serum between pre- and postmenopausal women, and observed the changes of levels of hCG-beta in animals suffering from hypertriglyceridemia. The results have shown that the concentration of hCG-beta in postmenopausal women is much higher than that in premenopausal women (P < 0.001). Correspondingly, triglyceride (TG) is elevated (P < 0.05). High density lipoprotein cholesterol (HDL-C) and HDL-C/LDL-C ratio are decreased (P < 0.001, P < 0.01). On the other hand, the tendency of highing hCG-beta level has been found in animal study. The concentration of hCG-beta in male rats suffering form hypertriglyceridemia is higher than that in normal animals (P < 0.05).

Is hypertension more severe among U.S. blacks, or is severe hypertension more common?

It is frequently stated that the risk of sequelae from hypertension at a given level of severity is higher among blacks than whites, although little empirical evidence supports that supposition. In this work we examined the basis for accepting the existence of a black: white differential in hypertension outcomes in a representative biracial sample of the U.S. population followed in the First National Health and Nutrition Examination Survey (NHANES-1) Epidemiologic Follow-up Study. As well recognized, the risk associated with increasing blood pressure is not dichotomous but varies across the entire distribution in a curvilinear fashion. The rightward skew of the blood pressure distribution with increasing mean levels affects comparisons between populations, since the change in shape results in a change in the mix of case severity. These considerations can influence estimates of the relative population-attributable risk from hypertension, considered as a dichotomous classification in blacks and whites. Although the relative risk of death associated with a systolic blood pressure of > or = 140 mmHg in this study was higher for blacks than for whites (1.7 and 1.5, respectively), with all-cause mortality as the outcome, the logistic coefficient for systolic blood pressure was not significantly different among white as compared with black men (beta = 0.016 vs. 0.010; p = 0.320 for race interaction term) and was slightly greater among white vs. black women (beta = 0.013 vs. 0.010; P = 0.05). After strata-specific blood pressure adjustment, the principal determinant of increased population risk for both black men and women was the higher prevalence of hypertension, not differential severity. The population-attributable risk for hypertension was at least two times higher among blacks because of the higher prevalence among them; moreover, the increased prevalence accounted for 10% of the interethnic difference in mortality. Data from this study indicate that hypertension was not more severe among individual blacks, simply more common in the population.

Short stature and risk of mortality and cardiovascular disease: negative findings from the NHANES I epidemiologic follow-up study

OBJECTIVES

This study sought to examine the relation between body height and incidence of myocardial infarction, coronary heart disease, overall mortality and mortality from cardiovascular disease.

BACKGROUND

An association between short stature and increased risk of fatal and nonfatal cardiovascular disease has been observed in several studies, attracting considerable attention.

METHODS

We used data from the First National Health and Nutrition Examination Survey (NHANES I) Epidemiologic Follow-Up Study, a prospective study of a large random sample of the U.S. population, to examine the association between height and risk of four end points.

RESULTS

Baseline data were collected from 1971 to 1975 for 13,031 respondents (5,296 men, 7,735 women), and the average follow-up period was 13 years, through 1987. Height was inversely associated with risk of all four of the end points studied in both men and women. However, after adjustment for age and years of education in Cox proportional hazards analyses, the relation no longer existed. Using the same adjustment procedures, persons in the lowest height quintile had no increase in risk compared with those in the highest category. The findings were consistent for men and women, blacks and whites and different age groups.

CONCLUSIONS

Data from this study in a national sample do not support the hypothesis of an inverse height-heart disease relation.

Cardiac cytotoxic mechanism mediated by antibodies against myocardial mitochondrial ADP/ATP carrier in patients with dilated cardiomyopathy

OBJECTIVE

To investigate mechanism of the antibody-mediated cardiac cytotoxicity and clinical significance in dilated cardiomyopathy (DCM), and study the effects of the antibodies against the myocardial mitochondrial ADP / ATP carrier from sera of patients with dilated cardiomyopathy on the guinea pig ventricular myocytes.

PATIENTS AND METHODS

This study included 18 patients with DCM (12 men and 6 women), with mean age of 43 years. Control group included 18 health donors, (9 men and 9 women), with mean age of 32 years. The antibodies against the ADP / ATP carrier and cell membrane 52 000 peptide were examined by immunoblotting. The antibody-mediated cardiac cytotoxicity was studied with the cytotoxic test and whole cell patch-clamp technique.

RESULTS

The antibodies against myocardial mitochondrial ADP / ATP carrier and cell membrane 52 000 peptide were positive in 18 patients with DCM, while negative in controls. The antibodies induced cytotoxic damage with time-dependent and enhanced Ca-current in cardiac myocytes. The increasing amplitude of peak Ca(2+)-current was 100 pA-840 pA (n = 8) in different dilution of the antibodies. The effect of the antibodies might be inhibited by verapamil, and were null in controls (n = 4).

CONCLUSIONS

The above findings suggest that an increase in the antibody-mediated Ca(2+)-current of cardiac myocytes is related to the cytotoxic damage in dilated cardiomyopathy.

Psychosocial correlates of chest pain among African-American women

While 10-30% of individuals with chest pain who undergo cardiac arteriography are found to have no demonstrable pathology, women are far more likely than men to have normal coronary arteries in the presence of angina. Black women, in particular, frequently seek medical attention for persistent episodes of chest pain. This cross-sectional study was designed to examine the potential role of psychological and social factors in relation to chest pain among black women. Among our population-based sample of 188 women, 48% reported experiencing chest pain. Seventeen of these cases met the Rose criteria for classification as cardiac pain while 74 of them reported pain not consistent with cardiac origin. A statistically significant difference was observed in the stress scores among the women; the highest stress scores occurred among those with Rose angina and the lowest scores were obtained from those women reporting no chest pain experiences (p < 0.001). There was no association detected between the presence and type of chest pain and psychosocial measures of depression and coping abilities. These results confirm the high rates of chest pain experienced among black women, and provide insight into the role of psychological factors that should be considered in the identification of treatment options.

Effect of beta-carotene supplementation on indices of colonic cell proliferation

BACKGROUND

Epidemiologic studies have shown that consuming foods containing beta-carotene is associated with a decreased incidence of colon cancer. The validity of this association has recently been questioned. It is not known if the rate of colonic cell proliferation differs among individuals with or without a history of colonic polyps or cancer and if proliferation changes in response to beta-carotene.

PURPOSE

This study was intended to (a) determine whether differences exist in colonic cell proliferation in individuals with and without prior colonic polyps or tumors, (b) demonstrate that beta-carotene accumulates in colonic mucosa following dietary supplementation, and (c) determine whether mucosal beta-carotene accumulation influences colonic cell proliferation.

METHODS

Subjects were enrolled in the phase I study from June 1991 until February 1994. The participants included 20 individuals (11 males and nine females, aged 62.3 +/- 8.9 years [means +/- SD]) with normal colons (as judged by recent colonoscopy), 40 (24 males and 16 females, aged 59.6 +/- 10.1 years) with a history of colonic polyp(s), and 41 (30 males and 11 females, aged 67.2 +/- 9.7 years) with prior colon cancer. The subjects in the last two groups consumed either 30 mg of beta-carotene or placebo each morning for 3 months. This dose of beta-carotene has no known toxic effects, but it can increase the serum level by approximately 10-fold. beta-carotene concentration in serum and colonic tissue was quantitated by high-pressure liquid chromatography in samples collected before and after supplementation with beta-carotene or placebo. Cellular proliferation was assessed on the basis of tissue ornithine decarboxylase activity, urinary polyamine excretion, and proliferating cell nuclear antigen expression. The differences in colonic cell proliferation parameters due to beta-carotene supplementation, within and among different groups, were evaluated by the Wilcoxon matched-pairs signed ranked test and the Mann-Whitney test, respectively. All statistical tests were two-sided.

RESULTS

Colonic cell proliferation did not differ in samples obtained from individuals with and without prior colonic polyp(s) or cancer. beta-carotene concentrations in serum and colonic tissue were significantly increased in groups receiving beta-carotene (P < .001). However, cell proliferation did not differ, as judged by any of the three measures, among samples from all experimental groups collected before and after supplementation with beta-carotene.

CONCLUSIONS

Dietary supplementation with beta-carotene for a period of 3 months does not alter colonic cell proliferation in individuals with a history of colonic polyps or cancer.

IMPLICATIONS

The mechanism by which beta-carotene might reduce colon cancer incidence does not appear to involve or result in a change in cell proliferation in the normal colonic mucosa as studied in individuals with a history of colonic polyps or cancer.

Left ventricular hypertrophy has a greater impact on survival in women than in men

BACKGROUND

Echocardiographically determined left ventricular hypertrophy (LVH) has a well-demonstrated association with cardiovascular morbidity and mortality. However, whether or not there is a sex differential in the impact of LVH on mortality has never been systematically explored.

METHODS AND RESULTS

This study enrolled 436 consecutive black patients (163 men and 273 women) free of angiographic coronary artery disease from a hospital registry. LVH (left ventricular [LV] mass/body surface area > or = 117 g/m2 in men and > or = 104 g/m2 in women) was present in 84 men (52%) and 119 women (44%). During a mean of 5 years' follow-up (range, 0 to 9), 49 patients (26 men and 23 women) died. The mortality rate was 5.40 per 100 patient-years in men with LVH and 2.58 in men without LVH (crude relative risk [RR] = 2.09) and 3.21 and 0.66, respectively, in women (RR = 4.87). In Cox regression analysis, adjusting for age, hypertension, and ejection fraction, the RR of total death for LVH versus non-LVH was 2.0 (95% confidence interval [CI], 0.8 to 5.0) in men and 14.3 (95% CI, 1.6 to 11.7) in women. For cardiac death, RR was 1.3 (95% CI, 0.4 to 3.7) and 7.5 (95% CI, 1.6 to 33.8) in men and women, respectively. Analyses using LV mass indexed by height or height with the use of different LVH cut points, comparing patients in the highest sex-specific tertile of mass index to those in the lower two tertiles, and the use of LV mass indexes as continuous variables similarly demonstrated a greater increase in risk of either fatal end point among women than men.

CONCLUSIONS

These findings indicate a sex difference in the contribution of LV mass and hypertrophy to mortality in the absence of coronary artery disease.

The chymase-angiotensin system in humans: biochemistry, molecular biology and potential role in cardiovascular diseases

Angiotensin I-converting enzyme (ACE) inhibitors are highly effective in the treatment of cardiovascular diseases. However, the relationship among the antihypertensive effects of ACE inhibitors, ACE inhibition and plasma angiotensin II levels is complex. During chronic therapy with ACE inhibition, plasma angiotensin II levels return to normal despite a continued antihypertensive effect. Recent studies show that a conversion of angiotensin I to angiotensin II in tissues can proceed despite complete ACE inhibition. In the search for a potential ACE inhibitor-resistant angiotensin II-forming enzyme activity in human heart tissue, chymase was identified as a major angiotensin II-forming enzyme. In primates, chymase-like angiotensin II-forming activity is localized in a number of tissues including the heart, blood vessels and lungs. Within the human heart, mast cells and endothelial cells are the sites of synthesis and storage of chymase, but a high level of the secreted chymase is also found in the cardiac interstitium, associated with the extracellular matrix. Mammalian chymases may be divided into two distinct structural groups, alpha and beta. alpha-chymases, such as human chymase, are highly specific and efficient angiotensin II-forming enzymes. beta-chymases, including several rat and mouse chymases, have a broad substrate specificity like chymotrypsin and do not form angiotensin II. In humans and baboons only a single chm gene of the alpha-subtype can be identified. By using an angiotensin I analogue that is selectively converted to angiotensin II by chymase and not ACE, a functional chymase-dependent angiotensin II formation has recently been demonstrated in conscious baboons.(ABSTRACT TRUNCATED AT 250 WORDS)

The relative effects of left ventricular hypertrophy, coronary artery disease, and ventricular dysfunction on survival among black adults

OBJECTIVE

To evaluate the effect of echocardiographically determined left ventricular hypertrophy (LVH) on survival in comparison with number of stenosed vessels and left ventricular systolic dysfunction.

DESIGN

Cohort study based on a consecutive sample from a hospital registry, with a mean follow-up of 5 years.

SETTING

An inner-city public hospital in Chicago, Ill.

PATIENTS

The study included 1089 consecutive black patients who underwent both coronary angiography and M-mode echocardiography as part of a diagnostic evaluation.

RESULTS

Nonstenosed coronary arteries, single-vessel disease, and multivessel disease were found in 48%, 16%, and 36% of patients, respectively; LVH (left ventricular mass index > 131 g/m2 in men and > 100 g/m2 in women) was detected in 50% of patients. Hypertrophy without coexistent obstructive coronary disease was associated with a lower survival rate than that observed for single-vessel disease and was similar to multivessel disease. When LVH, number of diseases vessels, and left ventricular dysfunction were subjected to multivariate analysis, hypertrophy conferred a relative risk (RR) of 2.4 (95% confidence interval [CI], 1.7 to 3.2). By comparison, the presence of a single stenosed vessel did not increase the risk of death. Multivessel disease and ejection fraction less than 45% were associated with an RR of 1.6 (95% CI, 1.1 to 2.2) and 2.0 (95% CI, 1.4 to 2.7), respectively. Calculation of the attributable risk fraction demonstrated that for every 100 deaths in this cohort, LVH independently accounted for 37. The corresponding attributable risk fractions were 1%, 22%, and 9% for single-vessel disease, multivessel disease, and ventricular dysfunction, respectively.

CONCLUSIONS

Left ventricular hypertrophy was associated with a greater RR and attributable risk than the traditional measures of coronary disease severity. The high prevalence and powerful risk of LVH make an important contribution to the adverse survival rates among black patients with heart disease and may account for much of the black-white differential.

Continued adverse trends in coronary heart disease mortality among blacks, 1980-91

An abrupt downturn in mortality rates from coronary heart disease occurred in the United States in the mid-1960s, and for the next decade all four major sex-race groups experienced virtually identical rates of decline. Beginning around the mid-1970s, however, trends for blacks and whites began to diverge, with a deceleration in the annual fall in rates for blacks. The recent release of mortality data extending through 1991, with correction of the denominator estimates in the 1980s using the 1990 census, demonstrate a striking linearity of this trend over the entire decade. In 1989, for the first time since the category of coronary heart disease has been recorded in vital statistics, the age-adjusted death rate for it among black men exceeded that of whites. As a result of the divergent trends among men, an excess of 4,000 deaths of blacks were recorded in 1991 alone. Among women, coronary heart disease mortality was higher among blacks at the beginning of this period, and the average annual percent decline was only two-thirds that of whites. As a result, the absolute mortality gap between blacks and whites steadily increased from 19 to 33 percent (1980 to 1991). This study indicates that the factors that have led to the decline in coronary heart disease have not influenced all demographic groups equally over the last decade.

Ambulatory blood pressure monitoring in normotensive children

OBJECTIVE

To assess reference values of ambulatory blood pressure in normotensive children.

SUBJECTS AND DESIGN

Twenty-four-hour non-invasive ambulatory blood pressure monitoring (ABPM) was carried out in 241 healthy normotensive children aged from 6 to 16 years (126 boys, mean +/- SD age 11.2 +/- 2.7 years; 115 girls, mean +/- SD age 10.9 +/- 2.9 years). The subjects were subdivided into three age-sex groups: 6-9, 10-12 and 13-16 years.

SETTING

Primary care.

MAIN OUTCOME MEASURES

ABPM was performed using an oscillometric device (SpaceLabs model 90207) and appropriate cuff size during a regular school day. Blood pressure was measured every 20 min from 0600 to 2400 h, and thereafter every 30 min. At each monitoring session the following parameters were calculated for both systolic (SBP) and diastolic blood pressure (DBP): means and centiles for 24-h, daytime (0800-2200 h) and night-time (2400-0600 h); circadian variability, estimated as the blood pressure fall between the day and the night periods and the day: night ratio; and load, as the percentage of measurements above the age- and sex-specific 95th centile (P95).

RESULTS

The upper limits of 'normality' for the mean of 24-h SBP and DBP estimated as the P95 in each age subgroup were 121/71 and 119/71 mmHg, 123/78 and 120/74 mmHg, and 124/78 and 125/75 mmHg, for boys and girls, respectively. A progressive increase in SBP with age was observed in both sexes, in contrast, DBP was similar throughout the age range. A nocturnal blood pressure fall of approximately 11 mmHg was observed for both SBP and DBP in all subgroups. The day:night ratio was 1.12 and 1.22 for SBP and DBP, respectively. The upper limit of blood pressure load, estimated as the P95 in all children, was 39% for SBP and 26% for DBP. A significant positive correlation was observed between casual blood pressure and 24-h ambulatory blood pressure (SBP: r = 0.61, P < 0.0001; DBP: r = 0.31, P < 0.0001). In general, mean ambulatory blood pressure, during the 24-h or the daytime period, was higher than casual blood pressure for both SBP and DBP.

CONCLUSION

ABPM is feasible in children, and the values obtained are useful as a departure point in establishing reference values.

Does heart transplantation confer additional benefit over medical therapy to patients who have waited > 6 months for heart transplantation?

OBJECTIVES

This study compared the survival of patients with heart failure who have waited > 6 months for heart transplantation with that patients who undergo heart transplantation after a similarly prolonged waiting period.

BACKGROUND

There are little data describing outcome in patients with severe heart failure who have waited for extended periods of time on the heart transplant waiting list.

METHODS

Sixty-three consecutive patients who spent > 6 months on the heart transplant waiting list were examined. Mean (+/- SD) age was 53 +/- 9 years, mean left ventricular ejection fraction was 19 +/- 6%, and all were taking digoxin and diuretic and vasodilator agents. Patients who underwent transplantation during the follow-up period were censored from the pretransplantation analysis, and their survival was examined as part of the posttransplantation phase of the study.

RESULTS

Of the 63 original patients examined, 25 underwent transplantation, 10 during inotropic or mechanical circulatory support. The pretransplantation mortality rate was 6% at 6 months after the 6-month milestone on the waiting list, 12% at 12 months and 22% at 18 months. The posttransplantation mortality rate was 5% at 6 months, 10% at 12 months and 24% at 18 months. There were no differences in survival at any time between the two phases of the study.

CONCLUSIONS

Survival of patients who have survived > 6 months on the heart transplant waiting list is generally good. Although heart transplantation did not appear to confer additional survival advantage over medical therapy, a large proportion of the patients who underwent transplantation were critically ill at the time of transplantation and would undoubtedly have died of progressive heart failure had they not undergone transplantation. We conclude that heart transplantation should still be considered a therapeutic alternative in patients with heart failure even after a prolonged waiting period on the heart transplant waiting list.

Factors related to the presence of microalbuminuria in essential hypertension

The objective of the present study was to assess factors related to the presence of microalbuminuria in essential hypertension. Ninety-five patients with essential hypertension (58 males and 37 females, mean age 38.6 +/- 6.1 years) who had never been treated previously for hypertension were included in the study. Patients with nephropathy or diabetes mellitus, hyperglycemia > 120 mg/dL, glomerular filtration rate < 80 mL/min/1.73 m2, urinary tract infection, or positive dipstick for albumin or glucose were excluded. Blood pressure, echocardiographically determined left ventricular mass, serum biochemistry, and lipid profile were obtained. Twenty-four-hour urinary albumin excretion (UAE) was measured on two separate days using an immunonephelometric assay. Microalbuminuria (UAE 30 to 300 mg/24 h) occurred in 26% of patients and was associated with higher diastolic blood pressure (DBP), left ventricular mass index (LVMI), and a higher prevalence of hypertriglyceridemia and hyperapolipoproteinemia B (apo-B). Logistic regression analysis showed that the risk of microalbuminuria was independently related to diastolic blood pressure and hypertriglyceridemia when controlling for age, sex, body mass index, LVMI, and apo-B. Multiple regression analysis likewise confirmed that both DBP and LVMI were linearly related to UAE independent of age, sex, body mass index, total cholesterol, triglycerides, and apo-B. In conclusion, our study indicates that among hypertensive patients with elevated excretion rates of urinary albumin, even at the subclinical level, an increased cardiovascular risk exists compared to normoalbuminuric patients with a similar blood pressure. Assessment of the presence of microalbuminuria may be useful in the evaluation and management of hypertension.

A north-south comparison of blood pressure and factors related to blood pressure in the People's Republic of China: a report from the PRC-USA Collaborative Study of Cardiovascular Epidemiology

OBJECTIVES

To compare blood pressures in northern (Beijing) and southern (Guangzhou) Chinese population samples aged 35-54 years, males and females, urban and rural, and to assess the role of blood pressure-related traits in explaining north-south differences.

DESIGN

Cross-sectional surveys were conducted in 1983-1984 of northern and southern populations employed in industry (urban) or farming (rural).

METHODS

In the north samples were selected from the Capital Iron and Steel Complex (urban) and Shijingshan district (rural); in the south samples from the Guangzhou Shipyard (urban) and Panyu County (rural) were used.

RESULTS

The number of subjects surveyed in north and south were 4706 and 4179, respectively: 1500 and 1052 urban males, and 717 and 914 rural males; and 1300 and 1061 urban females, and 1189 and 1152 rural females, respectively. Average systolic (SBP) and diastolic (DBP) blood pressures, were consistently higher in the north than in the south. SBP and DBP were significantly and independently related to age, body mass index, heart rate, use of antihypertensive drugs, serum triglycerides level, alcohol use (males only) and inversely to cigarette smoking. Northerners were older, taller, heavier and had higher body mass index and triglycerides level than southerners. With adjustment of SBP and DBP for blood pressure-related traits, north-south blood pressure differences decreased, but remained significant for urban males, rural males and rural females, with sizeable differences for rural samples in particular.

CONCLUSIONS

North-south differences in blood pressure in these samples are accounted for only partly by north-south differences in the cited blood pressure-related traits. The role of other traits requires assessment.

beta-Carotene supplementation results in an increased serum and colonic mucosal concentration of beta-carotene and a decrease in alpha-tocopherol concentration in patients with colonic neoplasia

The aim of this study was to evaluate the colonic mucosal beta-carotene (BC) concentration following supplementation with BC and to determine if an increase in BC concentration influences vitamin E (alpha-tocopherol) status. The concentration of BC and alpha-tocopherol was assessed in serum and colonic tissue obtained from subjects with a history of colonic polyps or resected cancer (Dukes A, B1, or B2). Serum and mucosal biopsy samples were obtained prior to and following 3 months daily p.o. supplementation with 30 mg of BC or placebo. The concentration of BC was significantly increased in serum and colonic mucosa from both polyp and cancer subjects following supplementation as compared to presupplementation values and values from subjects receiving a placebo. The concentration of alpha-tocopherol in serum from cancer subjects was significantly decreased in samples obtained at the end of 3 months of BC supplementation as compared to placebo-matched controls. In BC-supplemented polyp subjects the tissue concentration of alpha-tocopherol was also significantly decreased relative to presupplementation values. The results indicate that BC supplementation does result in a significant accumulation of BC in the colonic mucosa but that the alpha-tocopherol concentration in both serum and colonic tissue may be compromised by an increased intake of BC. The mechanism for the decrease in alpha-tocopherol in conjunction with the increase in BC will require further study in order to develop strategies which will prevent vitamin E deficiency in BC-supplemented individuals.

Ambulatory blood pressure and microalbuminuria in essential hypertension: role of circadian variability

OBJECTIVE

To assess the relationship of subclinical urinary albumin excretion with ambulatory and circadian variability of blood pressure.

DESIGN AND METHODS

Patients with essential hypertension (82 males and 59 females, mean +/- SD age 38.9 +/- 7.3 years) who had never been previously treated for hypertension were included in the study. Patients with nephropathy or diabetes mellitus, hyperglycemia > 120 mg/dl, glomerular filtration rate < 80 ml/min per 1.73 m2, urinary tract infection and positive dipstick for albumin or glucose were excluded. Twenty-four-hour ambulatory blood pressure monitoring on a regular working day using an oscillometric device was performed. Twenty-four-hour urinary albumin excretion was measured on two separate days using an immunonephelometric assay.

RESULTS

Microalbuminuric patients (urinary albumin excretion 30-300 mg/24 h, n = 31) had significantly higher mean ambulatory systolic blood pressure (SBP) and diastolic blood pressure (DBP) than those with normoalbuminuria (urinary albumin excretion < 30 mg/24 h, n = 96) during the 24-h, daytime (0800-2200 h) and night (2400-0600 h) periods, whereas for office blood pressure only DBP was significantly higher. Urinary albumin excretion was positively correlated with the means of SBP and DBP. Multiple regression analysis similarly confirmed that DBP during daytime was positively and day:night ratio of DBP inversely associated with urinary albumin excretion independent of age, sex and other parameters of ambulatory blood pressure.

CONCLUSIONS

In conclusion, the present study indicates that, in middle-aged essential hypertensive patients, the presence of microalbuminuria is a marker for the presence of higher values of blood pressure throughout a 24-h period.

Assessment of the intestinal retention of beta-carotene in humans

OBJECTIVE

Assessment of the intestinal absorption of beta-carotene (BC) in humans as well as plasma clearance of BC has been difficult. We have used the total gut washout method (TGWM) to assess BC retention during transit through the intestine, as well as the effect that different diets and age have on BC retention.

METHODS

HPLC was used to quantitate fecal and serum BC concentrations from young and elderly subjects who had undergone the TGWM to remove all intestinal contents prior to ingesting BC or placebo with or without a meal. Meals contained different combinations of calories and fat.

RESULTS

In subjects receiving no meal, 83% of ingested BC was recovered in rectal effluent collected within 24 hours post-BC administration. The quantity of BC in feces of individuals receiving meals was 49-71%. There was no significant change in serum concentrations of other carotenoids or retinoids following consumption of BC with any of the different meals. Interestingly, both diet and age influenced the efficiency of BC absorption. An increase in dietary fat content resulted in an higher serum BC concentration in young subjects within 8 and at 24 hours post BC administration, whereas a higher caloric content resulted in a decrease in serum BC concentration in older subjects within 8 hours of BC administration.

CONCLUSION

Results indicate that the TGWM provides an accurate means for assessing the intestinal retention of BC in humans.

Risk/benefit ratio of perioperative OKT3 in cardiac transplantation

To evaluate the risk/benefit ratio of perioperative OKT3 in cardiac transplant patients receiving triple-drug immunosuppression, patients who underwent cardiac transplantation between July 1, 1988 and December 31, 1989 (n = 33) and who received perioperative OKT3 were retrospectively compared with patients who underwent transplantation between January 1, 1990 and June 30, 1991 (n = 46), and who received no perioperative anti-T cell therapy. To allow similar follow-up, data were analyzed through June 30, 1990 for the OKT3 group and through December 31, 1991 for the no anti-T cell therapy group. Patients in the no anti-T cell therapy group waited longer for a donor organ; other pretransplant characteristics did not differ. The azathioprine dose 1 month after transplant was higher in the no anti-T cell therapy group (144 +/- 63 mg vs 109 +/- 55 mg, p = 0.016); other post-transplant immunosuppression was similar. The incidence of total and treated rejection and the time to the first rejection did not differ between the groups. The OKT3 group had a higher number of infections (0.8 +/- 0.9 vs 0.3 +/- 0.3, p = 0.006) and intravenously treated infections (0.5 +/- 0.6 vs 0.1 +/- 0.2, p = 0.004) per patient per month. Cytomegalovirus infection developed in 46% of the OKT3 group versus 22% of the no anti-T cell therapy group (p = 0.025). Patient survival did not differ between the groups. Thus, an immunosuppressive regimen that includes perioperative OKT3 increases infections, especially cytomegalovirus infections, without decreasing or delaying rejection or increasing survival.