A prospective study of hypertension and the incidence of kidney stones in men

OBJECTIVE

To examine whether hypertension predicts the incidence of kidney stone disease.

DESIGN

Prospective cohort study (the Olivetti Prospective Heart Study).

SETTING

The Olivetti factory in Southern Italy.

SUBJECTS

Five hundred and three male workers, aged 21 - 68 years, with no evidence of kidney stone disease at baseline. Follow-up 8 years.

MAIN OUTCOME MEASURES

Anthropometry, blood pressure, biochemistry and history of kidney stone disease were evaluated at the baseline examination in 1987. Occurrence of kidney stone disease was evaluated again in 1994-1995. Hypertension was defined as systolic blood pressure > or = 160 or diastolic blood pressure, > or = 95 mmHg or both, or being on drug therapy for hypertension. Occurrence of kidney stone disease was defined as radiological or echographic evidence of calculi or documented passage of one or more stones.

RESULTS

At baseline, 114/503 men (22.7%) had hypertension and 32 were on drug treatment. After 8 years, 52 (10.3%) incident cases of kidney stone disease were detected. The majority (n = 45) had a documented passage of one or more stones. The incidence of kidney stone disease was higher in hypertensive than in normotensive men (19/114 (16.7%) versus 33/389 (8.5%); P = 0.011). Hypertensive men had a greater risk of developing kidney stones than normotensive ones (RR 1.96; 95% confidence interval 1.16-3.32). The risk was unaffected by the exclusion of treated hypertensives (2.01; 1.13-3.59) and after adjustment for age (1.89; 1.12-3.18), body weight (1.78; 1.05-3.00) or height (2.00; 1.19-3.38).

CONCLUSIONS

Hypertension in middle-aged men is a significant predictor of kidney stone disease rather than a consequence of renal damage caused by the kidney stones.

Respiratory muscle function and hypoxic ventilatory control in patients with type I diabetes

STUDY OBJECTIVES

The interaction among pulmonary mechanics, respiratory muscle performance, and ventilatory control in subjects with insulin-dependent diabetes mellitus has so far received little attention. We therefore decided to assess the role of central factors and peripheral factors on the ventilatory response to a hypoxic stimulus in type I diabetic patients.

SUBJECTS

Eight patients in stable condition aged 19 to 48 years old, with insulin-dependent diabetes mellitus (duration of the disease, 36 to 240 months) and no history of smoking, cardiopulmonary involvement, or autonomic neuropathy; and an age- and gender-matched control group.

MEASUREMENTS

In each patient, we measured the following: pulmonary volumes; diffusing capacity of the lung for carbon monoxide (D(LCO)); time and volume components of ventilation (tidal volume [V(T)] and respiratory frequency); static compliance (Clstat) and dynamic compliance (Cldyn); swings in pleural pressure (Pes) and gastric pressure (Pg); and transdiaphragmatic pressure (Pdi), obtained by subtracting Pes from Pg. Maximal inspiratory Pes and Pdi during a maximal sniff maneuver were also measured. Swings in Pes and Pdi during V(T) as a percentage of Pes and Pdi during the maximal sniff maneuver [Pessw(%Pessn) and Pdisw(%Pdisn), respectively] were both considered as a measure of central respiratory output, and the Pessw(%Pessn)/V(T) ratio was considered as an index of neuroventilatory dissociation (NVD) of the inspiratory pump. Subjects were studied at baseline and during hypoxic rebreathing.

RESULTS

Pulmonary volumes and D(LCO) were normal or slightly reduced. A lower Cldyn, higher central respiratory output, and NVD were found. During hypoxic rebreathing, patients had lower V(T), similar central respiratory output, and greater NVD per unit change in arterial oxygen saturation compared with values in control subjects. An increase in dynamic elastance, computed as 1/Cldyn, during hypoxia was found in patients, but not in normal subjects, and was directly related to concurrent changes in NVD.

CONCLUSIONS

We have shown that the assessment of a normal Clstat and normal routine parameters of airway obstruction does not permit the definite exclusion of the role of peripheral airway involvement in insulin-dependent diabetes mellitus. Peripheral airway involvement is likely to influence indices of hypoxic ventilator) drive by modulating a normal central motor output into a rapid and shallow pattern of ventilatory response.

Dyspnoea, peripheral airway involvement and respiratory muscle effort in patients with type I diabetes mellitus under good metabolic control

Dyspnoea and pulmonary dysfunction have recently been associated with Type I (insulin-dependent) diabetes mellitus. The putative role of altered pulmonary mechanics and of performance of inspiratory muscles in inducing dyspnoea has not been yet assessed in Type I diabetes. To better focus on this topic we evaluated nine patients with Type I diabetes mellitus, aged 19 to 48 years with good and stable metabolic control, without a history of smoking and microvascular complications, alongside a group of 14 healthy control subjects. In each subject, pulmonary volumes, static and dynamic compliance, pleural pressure swings (Pplsw), maximal inspiratory pressures (Pplsn), Pplsw(%Pplsn), a measure of respiratory muscle effort, and tension-time index [TTI=TI/TTOTxPplsw(%Pplsn)] were measured (TI=inspiratory time;TTOT=total time of the respiratory cycle). All subjects were studied at baseline and during hypoxic rebreathing. Patients had normal pulmonary volumes. During hypoxic rebreathing, a normal change in respiratory muscle effort [DeltaPplsw(%Pplsn)/DeltaSaO2] and DeltaTTI/DeltaSaO2, and a lower change in tidal volume versus change in oxygen saturation [DeltaVT(% vital capacity)/DeltaSaO2], resulted in a higher ratio of respiratory effort to tidal volume [Pplsw(%Pplsn)/VT(% vital capacity)], a measure of neuroventilatory dissociation of the respiratory pump. Hypoxic dyspnoea, assessed by a modified Borg scale, showed a greater rate of rise (DeltaBorg/DeltaSaO2) and a greater increase for a given level of respiratory effort in patients. Moreover, neuroventilatory dissociation related to the expression of peripheral airway involvement, as assessed in terms of low dynamic compliance, and to concurrent change in dyspnoea sensation. Patients with Type I diabetes mellitus under good metabolic control and with normal lung volumes may have abnormal peripheral airway function. The latter is thought to be responsible for the association between dyspnoea sensation and neuroventilatory dissociation.

FMLP- and TNF-stimulated monoclonal Lym-1 antibody-dependent lysis of B lymphoblastoid tumour targets by neutrophils

Human neutrophils, incubated with Cr51-labelled B lymphoblastoid Raji cells in the presence of the anti-target monoclonal antibody (mAb) Lym-1 plus formyl-methionyl-leucyl-phenylalanine (FMLP) or tumour necrosis factor alpha (TNF-alpha), were found to induce significant C51 release, i.e. significant cytolysis. The lytic process was inhibited by mAb IV.3, specific for the Fcgamma receptor (FcgammaR) type II. The mAb 3G8, which reacts with FcgammaR type III, was ineffective. Moreover, the lysis was inhibited by the anti-CD18 mAb MEM-48. These data suggest that FMLP/Lym-1 as well as TNF-alpha/Lym-1 cytolytic systems strictly require FcgammaRII and CD18 integrins. As the lysis induced by TNF-alpha/Lym-1 was prevented by pertussis toxin (PT), PT-sensitive G-proteins are likely to intervene in post-FcgammaRII signal transduction. Both the FMLP- and the TNF-alpha-dependent systems were also found to be equally susceptible to inhibition by various inhibitors of kinases (genistein, staurosporin, 1-(5-isoquinolinnylsulphonyl)-2-methylpiperazine and wortmannin). On the contrary, an inhibitor of protein kinase C (bis-indolyl-maleimide, BIM) was effective only in the FMLP/Lym-1 cytolytic system. Therefore, it appears that signals delivered by FMLP or TNF-alpha, BIM-sensitive and insensitive respectively, converge and synergize with those from G-protein-coupled FcgammaRII and, probably, CD18-integrins to promote the expression of the neutrophil cytolytic potential.

Using IRT variable maps to enrich understanding of rehabilitation data

One of the benefits of item response theory (IRT) applications in scale development is the greater transparency of resulting scores. This feature allows translation of a total score on a particular scale into a profile of probable item responses with relative ease, for example by using the variable map that often is part of IRT analysis output. Although there have been a few examples in the literature using variable maps to enrich clinical interpretation of individual functional assessment scores, this feature of IRT output has received very limited application in rehabilitation research. The present paper illustrates the application of variable maps to support more in-depth interpretation of functional assessment scores in research and clinical contexts. Two examples are presented from an outcome prediction study conducted during the standardization of a new functional assessment for elementary school students with disabilities, the School Function Assessment. Two different applications are described: creating a dichotomous outcome variable using scores from a continuous scale, and interpreting the meaning of a classification cut-off score identified through Classification and Regression Tree (CART) analysis.

Immunization with a plasmid encoding a modified hepatitis B surface antigen carrying the receptor binding site for hepatocytes

Intramuscular injection of a plasmid encoding a modified hepatitis B surface antigen (HBsAg) induced humoral and cytotoxic responses in C57BL/6 mice. This modified HBsAg contains a preS1-derived peptide (amino acids 21 to 47), that carries the HBV receptor binding site for hepatocytes fused to the C-terminus of the small protein (at the position of amino acid 223). After a single DNA injection, the immunized mice elicited high titers of anti-HBs and anti-preS1 antibodies, and produced strong HBV specific cytotoxic T-lymphocyte (CTL) responses. The immune response induced after a single injection of this modified HBsAg gene in HBsAg-transgenic mice resulted in the clearance of circulating HBsAg and the appearance of anti-HBs and anti-preS1 antibodies. The high titers of preS1 antibody in transgenic mice were comparable to those found in non-transgenic controls and may be efficient to clear Dane particles existing in sera from chronic carriers. These data indicated that a genetic vaccine consisting of this modified HBsAg gene may have a potential use for both prophylactic and therapeutic purposes.

Controlled study of the effect of angiotensin converting enzyme inhibition versus calcium-entry blockade on insulin sensitivity in overweight hypertensive patients: Trandolapril Italian Study (TRIS)

OBJECTIVE

The aim of this study was to evaluate the effect of trandolapril, an angiotensin converting enzyme inhibitor, on blood pressure, forearm blood flow and insulin sensitivity in comparison with nifedipine gastrointestinal therapeutic system.

PATIENTS AND METHODS

This is a multicentre, two-way parallel-group, open-label comparative study in 90 overweight hypertensive patients, who were randomly assigned to treatment for 8 weeks with either trandolapril or nifedipine. At baseline and after treatment, all patients underwent an oral glucose tolerance test, an evaluation of their metabolic profiles and a euglycaemic hyperinsulinaemic clamp test. In a subgroup of 18 patients, a forearm study was carried out.

RESULTS

Blood pressure fell by the second week of treatment and remained significantly reduced compared with baseline in both treatment groups. Plasma triglyceride levels were also significantly reduced after trandolapril therapy, but no significant changes occurred in the other metabolic parameters during treatment with either drug. During the euglycaemic hyperinsulinaemic clamp, whole-body glucose use was similar in the two treatment groups at baseline, and a moderate but statistically significant increase in insulin sensitivity was observed after trandolapril treatment (trandolapril: 5.0 +/- 0.2 versus 4.5 +/- 0.2 mg/kg per min; nifedipine: 4.1 +/- 0.3 versus 4.2 +/- 0.3 mg/kg per min; P < 0.05, versus baseline and trandolapril versus nifedipine treatment). Skeletal muscle glucose uptake was significantly higher after trandolapril than after nifedipine therapy (5.0 +/- 0.7 and 3.0 +/- 0.4 mg/min, respectively; P < 0.01). As forearm blood flow was similar in the two treatment groups at baseline and was unchanged after 8 weeks of therapy, skeletal muscle glucose extraction was significantly greater in the ACE inhibitor treated-group than in the nifedipine comparative group (trandolapril: baseline 21 +/- 2, treatment 24 +/- 3 mg/dl; nifedipine: baseline 18 +/- 3, treatment 16 +/- 2 mg/dl; P < 0.05, trandolapril versus nifedipine treatment).

CONCLUSIONS

During short-term treatment, ACE inhibition with trandolapril was able to moderately improve insulin sensitivity, in comparison with calcium blockade, and this effect appeared to be independent of the haemodynamic action of the drug.

The cenpB gene is not essential in mice

Centromere protein B (CENP-B) is a centromeric DNA-binding protein that binds to alpha-satellite DNA at the 17 bp CENP-B box sequence. The binding of CENP-B, along with other proteins, to alpha-satellite DNA sequences at the centromere, is thought to package the DNA into heterochromatin subjacent to the kinetochore of mitotic chromosomes. To determine the importance of CENP-B to kinetochore assembly and function, we generated a mouse null for the cenpB gene. The deletion removed part of the promoter and the entire coding sequence except for the carboxyl-terminal 35 amino acids of the CENP-B polypeptide. Mice heterozygous or homozygous for the cenpB null mutation are viable and healthy, with no apparent defect in growth and morphology. We have established mouse embryo fibroblasts from heterozygous and homozygous cenpB null littermates. Microscopic analysis, using immunofluorescence and electron microscopy of the cultured cells, indicated that the centromere-kinetochore complex was intact and identical to control cells. Mitosis was identical in fibroblasts derived from cenpB wild-type, heterozygous and null animals. Our studies demonstrate that CENP-B is not required for the assembly of heterochromatin or the kinetochore, or for completion of mitosis.

Regulation of hepatitis B virus mRNA expression in a hepatitis B surface antigen transgenic mouse model by IFN-gamma-secreting T cells after DNA-based immunization

The immunotherapeutic effect of DNA-mediated immunization against chronic hepatitis B virus (HBV) infection has been evaluated in transgenic mice expressing the sequences that code for the envelope proteins of HBV in the liver. In this model of HBV chronic carriers, a single i.m. injection of plasmid DNA encoding HBV envelope proteins is sufficient to generate specific immune responses leading to the clearance of the transgene expression product and the control of HBV mRNA. The relative contributions of the T cell subpopulations induced by DNA immunization were examined using adoptive transfer experiments. It was shown that either CD8+ or CD4+ T lymphocytes from immunocompetent DNA-immunized animals were sufficient to control viral gene expression in the livers of the recipient transgenic mice. This effect was mediated by a cytokine-dependent mechanism common to both T cell subpopulations; this mechanism did not require cell lysis, but did involve the production of IFN-gamma by the activated T cells.

Measurement of the Cost of Screening for Cervical Cancer in the District of Florence, Italy

AIMS AND BACKGROUND

To estimate the cost per woman examined and per CIN II or more severe lesion detected in a population-based cytologic screening program for cervical cancer prevention. An organized cytologic screening program has been ongoing in the Florence District since 1973, and a call-recall system using mail invitation has been ongoing since 1980. Smear reading and assessment of screening positives is centralized at the screening unit.

METHODS AND STUDY DESIGN

All relevant resources (costs) consumed by the program were listed and measured. The unit cost per examined woman and per each CIN II or more severe lesion detected was estimated for each screening phase (recruitment, screening, assessment).

RESULTS

The cost per examined woman was $24.60, whereas that per CIN II or more severe lesion detected was $13,600. Staff accounted for 80% of total amount.

CONCLUSIONS

Although the cost for a single procedure is low, the cost per detected lesion is quite remarkable due to the low detection rate in a population screened for a long time. Different approaches and longer interval screening tests are discussed.

Treatment challenges in hypercholesterolemia

Primary and secondary prevention trials in individuals with high plasma cholesterol levels have proven that cholesterol-lowering drug treatment significantly reduces the risk of coronary heart disease (CHD) morbidity and mortality, and prolongs life. The degree of clinical benefit derived from such treatment appears to be proportional to the percentage reduction in plasma cholesterol. Regression and reduced progression of atherosclerosis may partially account for the clinical gains derived from lipid-lowering drug therapy; however, other direct mechanisms may be operative, including reduced atherogenicity of macrophages, improved vascular vasodilation, and reduced thrombogenesis. Specific treatment is determined on the basis of LDL cholesterol levels and overall global risk for CHD, that is, the presence of CHD and/or other CHD risk factors. Angiographic and clinical data support intensive lipid-lowering therapy in all hypercholesterolemic patients with CHD and those with high CHD risk, particularly those with ultrasonographic evidence (but no symptoms) or clinical signs of extracoronary atherosclerosis. Selection criteria for monotherapy include LDL-cholesterol lowering efficacy, CHD morbidity/mortality and overall survival benefits, no adverse effect on concomitant metabolic diseases (e.g., diabetes), tolerability, long-term safety, simple dose schedule, and cost effectiveness. However, in refractory hypercholesterolemia combination therapy may be required. Secondary prevention and primary prevention in individuals at high CHD risk are cost effective.

Ethnic differences in red blood cell sodium/lithium countertransport and metabolic correlates of hypertension: an international collaborative study

Arterial hypertension is frequently associated with metabolic abnormalities. An abnormal activity of the erythrocyte sodium/lithium countertransport (Na/Li CT), an ion transport system under strong genetic control, is also found in people with hypertension and concomitant metabolic abnormalities. However, little information exists with regard to these clinical associations in different racial groups. The aim of this international collaborative study was to investigate Na/Li CT and the metabolic correlates of hypertension in two comparable samples of normotensive and hypertensive populations in the cities of Naples, Italy, and Shanghai, China, using identical, carefully standardized techniques. Blood pressure, anthropometric and metabolic variables, Na/Li CT, and 24-h urinary Na and K excretion were measured in untreated essential hypertensive (HPT) and normotensive (NT) individuals selected by age (35-60 years), body mass index (BMI; < 30 kg/m2), and blood pressure (BP; HPT, DBP > or = 95 mm Hg; NT, DBP < 90 mm Hg). The analysis of variance with adjustment for age was used to compare the groups. In the Neapolitan population, hypertensive individuals had higher serum triglyceride (P < .05) and uric acid levels (P < .001) than the normotensive group and also had a reduced glucose tolerance (P < .01) and an enhanced insulin response to the oral glucose tolerance test (OGTT) (P < .05). No such differences were seen between normotensive and hypertensive Chinese participants. The Neapolitan population (both NT and HPT) had a higher BMI (P < .01) than their Chinese peers. In the comparison of hypertensive patients in Shanghai and in Naples, the Neapolitans were heavier (P < .001), had a lower HDL/total cholesterol ratio (P < .01), an elevated fasting blood glucose (P < .05), and also a higher glucose (P < .001) and insulin response (P < .001) to OGTT. By contrast, they showed a significantly lower urinary Na/K ratio (P < .001). Na/Li CT was significantly increased in HPT both in Naples (286 +/- 24 v 224 +/- 13 micromol/L RBC x h; P < .05, M +/- SE) and in Shanghai (388 +/- 45 v 265 +/- 30 micromol/L RBC x h; P < .05). Furthermore, Na/Li CT was significantly and inversely associated with HDL cholesterol both in the Neapolitan (P < .01) and in the Chinese (P < .05) population, whereas it was directly correlated with serum triglyceride (P < .001) and serum uric acid (P = .001) only in the Neapolitan population. These results indicate that essential hypertension is associated with a higher prevalence of obesity, impaired glucose tolerance, and hyperinsulinemia in Naples than in Shanghai; and Na/Li CT is linked to both high blood pressure and metabolic abnormalities in the Italian sample, whereas it is an isolated marker of hypertension in the Chinese sample.

BCR-ABL antisense oligodeoxynucleotide in vitro purging and autologous bone marrow transplantation for patients with chronic myelogenous leukemia in advanced phase

BCR-ABL antisense oligodeoxynucleotides (ODN) have provided evidence of antileukemia effect when tested in vitro against Philadelphia-positive (Ph-pos) cells and in vivo when injected into leukemic mice. On the basis of the results obtained in vitro at diagnosis, eight patients with chronic myelogenous leukemia (CML) were selected and submitted to autologous bone marrow transplantation (ABMT) with bone marrow (BM) cells purged in vitro with junction-specific (J-sp) BCR-ABL antisense ODN at the time of transformation in accelerated phase or during second chronic phase. Mononuclear BM cells were treated in vitro for 24 or 72 hours with 150 micro/mL of antisense ODN yielding a median recovery of 47.6% mononuclear cells, 48.8% CD34(+) cells, and 20.3% clonogenic cells. After a conditioning regimen including busulphan and etoposide, the reinfused treated cells allowed engraftment and hematologic reconstitution in all patients. Evaluation of the antileukemic effect by standard cytogenetic analysis and fluorescence in situ hybridization showed a complete karyotypic response in two cases and a minimal or no response in the other six. The patient autografted in second chronic phase died in blast crisis 7 months after ABMT; of the seven patients autografted in transformation, three developed blast crisis 21 to 39 months after reinfusion, one died from unrelated BMT complications 30 months after ABMT, and three are in persistent second chronic phase 14 to 26 months after autograft. The low toxicity of the protocol and the hemopoietic reconstitution observed in all patients make this approach feasible; the marked karyotypic response observed in some patients and the duration of the second chronic phase show that ODN-mediated BM purging and autograft is a promising treatment for this high-risk group of CML.

Hematological malignancies with a deletion of 11q23: cytogenetic and clinical aspects. European 11q23 Workshop participants

Balanced translocations of 11q23 are associated with specific clinical features and a poor outcome, but the relevance of deletions involving 11q23 is not clear. Fifty-seven patients with this deletion were collected by the Workshop, 30 had terminal and 27 had interstitial deletions. Twenty-seven patients had acute lymphoblastic leukemia (ALL), 16 had acute myeloid leukemia (AML), one had acute biphenotypic leukemia, one had acute undifferentiated leukemia and 12 had myelodysplastic syndrome (MDS). ALL patients had a median age of 7 years, median white blood cell count (WBC) of 15 x 10(9)/l, and 10/24 had common ALL. AML patients had a median age of 23 years, a median WBC of 49 x 10(9)/l, and 9/16 had M4 or M5. MDS patients were all adult, median age of 69 years, median WBC of 3 x 10(9)/l, and 7/12 had refractory anemia. The clinical outcome depended on diagnosis: children with ALL had a better prognosis (4/16 relapsed, one died) than AML patients; all adults and children with AML and 5/12 MDS patients died. Fluorescence in situ hybridization (FISH) identified 3 del(11q23) as translocations or insertions. Molecular studies revealed a MLL rearrangement in 8/10 patients. Because the involvement of MLL might be of prognostic relevance, identification of a del(11q23) should be an indication for FISH and molecular studies.

Flow cytometric measurement of mitochondrial mass and function: a novel method for assessing chemoresistance

BACKGROUND

Chemotherapeutic agents induce apoptosis in cancer cells. Drugs failing to induce apoptosis are likely to have decreased clinical efficacy. We hypothesize that (1) chemotherapeutic agents induce mitochondrial changes and apoptosis through mechanisms associated with reactive oxidant species production; (2) the anti-apoptotic protein Bcl-2 prevents drug-induced mitochondrial changes, reactive oxygen species (ROS) production, and apoptosis; and (3) the assay of drug-induced mitochondrial changes can reflect drug-specific chemoresistance in a given cancer cell line.

METHODS

A stable Bcl-2 transfectant of the Bcl-2 negative breast cancer cell line SKBr3 was created (SKBr3/Bcl2-2). Both SKBr3 and SKBr3/Bcl2-2 cells were treated with Herbimycin A (300 ng/mL) or vehicle (1% DMSO). Cell cycle changes were assessed by BRDU staining. Apoptosis was determined by electron microscopy, TUNEL (TdT-mediated dUTP-biotin nick end labeling) staining, and diphenylamine assay of DNA fragmentation. Changes in mitochondrial mass and transmembrane potential (deltapsi(m)) were assessed by flow cytometric assessment of JC-1 fluorescence. Reactive oxygen species production was measured by 2',7'-dichlorodihydrofluorescein diacetate (DCFH) fluorescence.

RESULTS

Both SKBr3 and SKBr3/Bcl2-2 cells show cell cycle arrest after Herbimycin treatment. However, SKBr3 cells, but not SKBr3/Bcl2-2 cells, undergo apoptosis. Herbimycin-treated SKBr3 cells show increased mitochondrial mass (JC-1 green fluorescence), with no corresponding increase in deltapsi(m) (JC-1 red fluorescence). By contrast, Herbimycin-treated SKBr3/Bcl2-2 cells show no change in mitochondrial mass or deltapsi(m). Similarly, drug-treated SKBr3 cells, but not SKBr3/Bcl2-2 cells, demonstrate increased reactive oxygen species (ROS) production concomitant with the development of apoptosis.

CONCLUSION

SKBr3 cells undergoing apoptosis demonstrate mitochondrial changes associated with ROS production. Bcl-2 transfection prevents these changes because it prevents apoptosis and induces chemoresistance to Herbimycin in SKBr3. Flow cytometric measurement of drug induced mitochondrial changes and ROS production may facilitate in vitro assessment of chemosensitivity or chemoresistance in breast cancer.

Bcl-2 slows in vitro breast cancer growth despite its antiapoptotic effect

BACKGROUND

Although the Bcl-2 protein promotes tumor cell survival by blocking programmed cell death (apoptosis), Bcl-2 expression has been associated with favorable prognostic indicators in breast cancer. We hypothesize that despite its antiapoptotic effects, Bcl-2 slows tumor cell proliferation.

MATERIALS AND METHODS

Bcl-2-negative breast cancer cells (SKBr3) were transfected with the bcl-2 gene (Bcl2-1 clone, low expression; Bcl2-2 clone, high expression) or plasmid control (Neo). Cell cycle distribution and kinetics were analyzed using bivariate flow cytometry (PI staining and pulse BrdU uptake). Cells were treated for 72 h with doxorubicin (100 ng/ml) or vehicle (0.01% DMSO) and assayed for cytosolic DNA with diphenylamine to measure apoptosis.

RESULTS

Cell counting showed increased doubling time in the Bcl-2-expressing clones Bcl2-1 and Bcl2-2 (Bcl-2(+)) relative to the Bcl-2-nonexpressing lines SKBr3 and Neo (Bcl-2(-)). Cell cycle analysis showed a decreased S phase fraction in Bcl-2(+) cells. Pulse BrdU uptake showed an increased G1/G0 fraction in Bcl-2(+) cells. Doxorubicin-induced apoptosis occurred in Bcl-2(-) but not in Bcl-2(+) cell lines.

CONCLUSIONS

Despite antiapoptotic effects favoring tumor survival, Bcl-2 prolongs cell cycle. Decreased tumor proliferation may account for the association of Bcl-2 expression with a favorable outcome in breast cancer, even though Bcl-2 may mediate chemoresistance in some patients.

One-year treatment with ethyl esters of n-3 fatty acids in patients with hypertriglyceridemia and glucose intolerance: reduced triglyceridemia, total cholesterol and increased HDL-C without glycemic alterations

n-3 Fatty acids in the form of ethyl esters (EE) allow lower daily doses and improved compliance. Administration of n-3 fatty acids to patients with glucose intolerance has led to controversial findings, some studies indicating worsening of the disorder, others no effect, or an improvement. A total of 935 patients with hypertriglyceridemia, associated with additional cardiovascular risk factors, i.e. glucose intolerance, NIDDM and/or arterial hypertension were entered a double blind (DB) protocol lasting 6 months with n-3 EE versus placebo, followed by a further 6 months of open study (n = 868) on 2 g a day of n-3 EE. At the end of the DB period, triglyceridemia in the total group was reduced significantly more by n-3 EE, without alterations in glycemic parameters. In the 6 months open follow up, patients on n-3 EE with type IIB hyperlipoproteinemia showed a significant reduction of total cholesterol, both in cases with (-4.15% vs. the 6 month levels) and without NIDDM (-3.8%). HDL-cholesterol had an overall mean rise of 7.4%, maximal in type IV patients with (+9.1%) and without (+10.1%) NIDDM. No alterations in glycemic parameters were detected in treated patients. Administration of n-3 EE to patients with hypertriglyceridemia associated with NIDDM or impaired glucose tolerance appears safe and effective.

The caspase-3 precursor has a cytosolic and mitochondrial distribution: implications for apoptotic signaling

Caspase-3-mediated proteolysis is a critical element of the apoptotic process. Recent studies have demonstrated a central role for mitochondrial proteins (e.g., Bcl-2 and cytochrome c) in the activation of caspase-3, by a process that involves interaction of several protein molecules. Using antibodies that specifically recognize the precursor form of caspase-3, we demonstrate that the caspase-3 proenzyme has a mitochondrial and cytosolic distribution in nonapoptotic cells. The mitochondrial caspase-3 precursor is contained in the intermembrane space. Delivery of a variety of apoptotic stimuli is accompanied by loss of mitochondrial caspase-3 precursor staining and appearance of caspase-3 proteolytic activity. We propose that the mitochondrial subpopulation of caspase-3 precursor molecules is coupled to a distinct subset of apoptotic signaling pathways that are Bcl-2 sensitive and that are transduced through multiple mitochondrion-specific protein interactions.