Are angiotensin II receptor blockers more efficacious than placebo in heart failure? Implications of ELITE-2. Evaluation of Losartan In The Elderly

In the light of the recent randomized controlled trials in chronic heart failure, it is now commonly assumed that treatment with an angiotensin-receptor blocker (ARB) is equivalent to treatment with an angiotensin-converting enzyme (ACE) inhibitor. We performed an imputed placebo analysis using previous placebo-ACE inhibitor trials and the current ACE inhibitor-ARB comparison studies, which shows that ARBs may not even be superior to placebos, let alone an ACE inhibitor.

Oxidative stress and vascular damage in hypertension

Oxidative stress, a state of excessive reactive oxidative species activity, is associated with vascular disease states such as hypertension. In this review, we discuss the recent advances in the field of reactive oxidative species-mediated vascular damage in hypertension. These include the identification of redox-sensitive tyrosine kinases, the characterization of enzymatic sources of superoxide production in human blood vessels, and their relationship with vascular damage in atherosclerosis and hypertension. Finally, recent developments in the search for strategies to attenuate vascular oxidative stress are reviewed.

Potent vasodilator responses to human urotensin-II in human pulmonary and abdominal resistance arteries

The peptide human urotensin-II (hUT-II) and its receptor have recently been cloned. The vascular function of this peptide in humans, however, has yet to be determined. Vasoconstrictor and vasodilator responses to hUT-II were investigated in human small muscular pulmonary arteries [approximately 70 microm internal diameter (ID)] and human abdominal resistance arteries (approximately 200 microm ID). Vasodilator responses were investigated in endothelin-1 (3 nM) precontracted vessels and, in the small pulmonary vessels, compared with the known vasodilators adrenomedullin, sodium nitroprusside, and acetylcholine. In human small pulmonary arteries, hUT-II did not induce vasoconstriction but was a potent vasodilator [-log M concentration causing 50% of the maximum vasodilator effect (pIC(50)) 10.4 +/- 0.5; percentage of reduction in tone (E(max)) 81 +/- 8% (vs. 23 +/- 11% in time controls), n = 5]. The order of potency for vasodilation was human urotensin-II = adrenomedullin (pIC(50) 10.1 +/- 0.4, n = 6) > sodium nitroprusside (pIC(50) 7.4 +/- 0.2, n = 6) = acetylcholine (pIC(50) 6.8 +/- 0.3, n = 6). In human abdominal arteries, hUT-II did not induce vasoconstriction but was a potent vasodilator [pIC(50) 10.3 +/- 0.7; E(max) 96 +/- 8% (vs. 43 +/- 16% in time controls), n = 4]. This is the first report that hUT-II is a potent vasodilator but not a vasoconstrictor of human small pulmonary arteries and systemic resistance arteries.

Conditional immortalization of freshly isolated human mammary fibroblasts and endothelial cells

Reports differ as to whether reconstitution of telomerase activity alone is sufficient for immortalization of different types of human somatic cells or whether additional activities encoded by other "immortalizing" genes are also required. Here we show that ectopic expression of either the catalytic subunit of human telomerase (hTERT) or a temperature-sensitive mutant (U19tsA58) of simian virus 40 large-tumor antigen alone was not sufficient for immortalization of freshly isolated normal adult human mammary fibroblasts and endothelial cells. However, a combination of both genes resulted in the efficient generation of immortal cell lines irrespective of the order in which they were introduced or whether they were introduced early or late in the normal proliferative lifespan of the cultures. The order and timing of transduction, however, did influence genomic stability. Karyotype analysis indicated that introduction of both transgenes at early passage, with hTERT first, yielded diploid cell lines. Temperature-shift experiments revealed that maintenance of the immortalized state depended on continued expression of functional U19tsA58 large-tumor antigen, with hTERT alone unable to maintain growth at nonpermissive temperatures for U19tsA58 large-tumor antigen. Such conditional diploid lines may provide a useful resource for both cell engineering and for studies on immortalization and in vitro transformation.

Myostatin, a negative regulator of muscle growth, functions by inhibiting myoblast proliferation

Myostatin, a member of the transforming growth factor-beta (TGF-beta) superfamily, has been shown to be a negative regulator of myogenesis. Here we show that myostatin functions by controlling the proliferation of muscle precursor cells. When C(2)C(12) myoblasts were incubated with myostatin, proliferation of myoblasts decreased with increasing levels of myostatin. Fluorescence-activated cell sorting analysis revealed that myostatin prevented the progression of myoblasts from the G(1)- to S-phase of the cell cycle. Western analysis indicated that myostatin specifically up-regulated p21(Waf1, Cip1), a cyclin-dependent kinase inhibitor, and decreased the levels and activity of Cdk2 protein in myoblasts. Furthermore, we also observed that in myoblasts treated with myostatin protein, Rb was predominately present in the hypophosphorylated form. These results suggests that, in response to myostatin signaling, there is an increase in p21 expression and a decrease in Cdk2 protein and activity thus resulting in an accumulation of hypophosphorylated Rb protein. This, in turn, leads to the arrest of myoblasts in G(1)-phase of cell cycle. Thus, we propose that the generalized muscular hyperplasia phenotype observed in animals that lack functional myostatin could be as a result of deregulated myoblast proliferation.

Identification of genes differentially expressed in association with acquired cisplatin resistance

The goal of this study was to identify genes whose mRNA levels are differentially expressed in human cells with acquired cisplatin (cDDP) resistance. Using the parental UMSCC10b head and neck carcinoma cell line and the 5.9-fold cDDP-resistant subline, UMSCC10b/Pt-S15, two suppressive subtraction hybridization (SSH) cDNA libraries were prepared. One library represented mRNAs whose levels were increased in the cDDP resistant variant (the UP library), the other one represented mRNAs whose levels were decreased in the resistant cells (the DOWN library). Arrays constructed with inserts recovered from these libraries were hybridized with SSH products to identify truly differentially expressed elements. A total of 51 cDNA fragments present in the UP library and 16 in the DOWN library met the criteria established for differential expression. The sequences of 87% of these cDNA fragments were identified in Genbank. Among the mRNAs in the UP library that were frequently isolated and that showed high levels of differential expression were cytochrome oxidase I, ribosomal protein 28S, elongation factor 1alpha, alpha-enolase, stathmin, and HSP70. The approach taken in this study permitted identification of many genes never before linked to the cDDP-resistant phenotype.

Plasmepsins as antimalarial targets

Since aspartic proteinases fulfil a crucial role in malarial parasite nutrition by mediating the degradation of host proteins, they have become targets for the production of new antimalarial agents. Two proteinases, plasmepsin I and plasmepsin II, have been well characterized, but whilst some progress has been made towards the production of plasmepsin inhibitors, selectivity remains a problem. The most deadly malarial parasite, Plasmodium falciparum, encodes at least two other aspartic proteinases (plasmepsin III and IV) and a related histo-aspartic protein. Since the sequences of plasmepsin III and the histo-aspartic protein are considerably different from those of human aspartic proteinases, they may be better potential targets for drug design.

Child development services in Medicaid managed care organizations: what does it take?

OBJECTIVE

We sought to understand why certain Medicaid managed care organizations (MMCOs) implemented child development services or programs and how they had done so. We also sought to identify barriers and facilitators to successful initiation and implementation of child development programs.

METHODS

We conducted 9 key informant interviews and 4 site visits, and performed qualitative analyses to identify major themes across responses.

RESULTS

We identified a small number of MMCOs with child development services. High-level support was crucial for program initiation; physician buy-in, staff support, and strong working relationships with outside health professionals or agencies were principal factors in successful program implementation.

CONCLUSIONS

MMCOs that were committed to implementing child development services were successful in doing so, without external funding or regulatory mandate. The results provide valuable strategies for MMCOs interested in developing programs and for researchers and advocates interested in promoting child development services for low-income children.

Nine novel L1 CAM mutations in families with X-linked hydrocephalus

Mutations in the gene for neural cell adhesion molecule L1 are responsible for the highly variable phenotype found in families with X-linked hydrocephalus, MASA syndrome, and spastic paraplegia type I. To date, 32 different mutations have been observed, the majority being unique to individual families. Here, we report nine novel mutations in L1 in 10 X-linked hydrocephalus families. Four mutations truncate the L1 protein and eliminate cell surface expression, and two would produce abnormal L1 through alteration of RNA processing. A further two of these mutations are small in-frame deletions that have occurred through a mechanism involving tandem repeated sequences. Together with a single missense mutation, these latter examples contribute to the growing number of existing mutations that affect short regions of the L1 protein that may have particular functional significance.

Prevalence of malnutrition on admission to four hospitals in England. The Malnutrition Prevalence Group

AIMS

The primary objective was to estimate prevalence of malnutrition on admission to four hospitals. Secondary objectives included assessing the relationship between nutritional status and length of hospital stay, numbers of new prescriptions, new infections and disease severity.

METHODS

We entered eligible patients according to predefined quotas for elective and emergency admissions to 23 specialties. We measured height, weight, Body Mass Index and anthropometrics, and recorded history of unintentional weight loss. Patients who had lost > or = 10% of their body weight, had a Body Mass Index <20, or had a Body Mass Index <20 with one anthropometric measurement <15th centile were considered malnourished.

RESULTS

Of 1611 eligible patients, 761 did not participate; 269 were too ill; 256 could not be weighed; and 236 refused consent. Eight hundred and fifty were subsequently evaluated. Prevalence of malnutrition on admission was 20%. Length of stay, new prescriptions and infections and disease severity were significantly higher in the malnourished.

CONCLUSIONS

One patient in every five admitted to hospital is malnourished. Although this figure is unacceptably high, it may underestimate true prevalence. Malnutrition was associated with increased length of stay, new prescriptions and infections. Malnutrition may also have contributed to disease severity.

Investigation into the sources of superoxide in human blood vessels: angiotensin II increases superoxide production in human internal mammary arteries

BACKGROUND

Increased vascular superoxide anion (.O(2)(-)) production contributes to endothelial dysfunction and hypertension in animal models of cardiovascular disease. Observations in experimental animals suggest that angiotensin II (Ang II) increases.O(2)(-) production by activation of vascular NAD(P)H oxidase. We studied the sources of.O(2)(-) production in human blood vessels and investigated whether, and by what mechanism, Ang II might alter vascular.O(2)(-) production.

METHODS AND RESULTS

Internal mammary arteries (IMAs) and saphenous veins (SVs) were collected at the time of cardiac surgery. Vessels were incubated in Krebs buffer at 37 degrees C.O(2)(-) was measured by lucigenin chemiluminescence. Basal. O(2)(-) concentrations were greater in IMAs than SVs. Inhibitors of NAD(P)H oxidase (10 micromol/L to 200 micromol/L diphenyleneiodonium) and xanthine oxidase (1 mmol/L allopurinol) caused reductions in.O(2)(-) concentrations in both IMAs and SVs. Western blotting of superoxide dismutase proteins demonstrated similar expression in IMAs and SVs. Vessels were also incubated in the presence or absence of Ang II (1 pmol/L to 1 micromol/L). Ang II increased.O(2)(-) production in IMAs at 4 hours of incubation (control, 978+/-117 pmol. min(-1). mg(-1); 1 micromol/L of Ang II, 1690+/-213 pmol. min(-1). mg(-1); n=27, P=0.0001, 95% CI 336, 925) but not in SVs. This effect was completely inhibited by coincubation of IMAs with DPI (100 micromol/L), a nonspecific Ang II antagonist ([sar(1), thre(8)]-Ang II, 1 micromol/L) and a specific Ang II type 1 (AT(1)) receptor antagonist (losartan, 1 micromol/L). Conclusions-. O(2)(-) production is greater in human IMAs than in SVs. NAD(P)H oxidase and xanthine oxidase are sources of.O(2)(-) production in these vessels. The vasoactive peptide Ang II increases.O(2)(-) production in human arteries by an AT(1) receptor-dependent mechanism.

Response of leucine metabolism to hyperinsulinemia in hypothyroid patients before and after thyroxine replacement

We have investigated the effect of hypothyroidism and insulin on protein metabolism in humans. Six hypothyroid patients were studied in a postabsorptive state before and after 5 months of regular treatment for hypothyroidism (153 +/- 17 microg/day of L-T4). The effect of insulin was assessed under hyperinsulinemic euglycemic and eukalemic conditions. Insulin was infused for 140 min at 0.0063 +/- 0.0002 nmol/kg x min. An amino acid infusion was used to blunt insulin-induced hypoaminoacidemia. Whole body protein turnover was measured using L-[1-13C] leucine. When compared to L-T4-induced subclinical thyrotoxic state, hypothyroidism induced a significant decrease (P < 0.05) in leucine endogenous appearance rate (a reflection of proteolysis; 0.89 +/- 0.09 vs. 1.33 +/- 0.05 micromol/kg x min), oxidation (0.19 +/- 0.02 vs. 0.25 +/- 0.03 micromol/kg x min), and nonoxidative disposal (a reflection of protein synthesis; 0.87 +/- 0.11 vs. 1.30 +/- 0.05 micromol/ kg x min). Insulin lowered proteolysis during both the subclinical thyrotoxic and hypothyroid states. Hypothyroidism impaired the antiproteolytic effects of insulin. Thyroid hormones are, therefore, essential for the normal antiproteolytic action of insulin.

Happy alone? Sad young men in East Asian gay cinema

This essay chooses as its texts three films representing contemporary gay male subjects from each of the "three" China's: HK, Taiwan, and the Mainland. Relocating the homoerotic image of the "sad young man," a trope popular from Hollywood rebellion films of the 1950s and 1960s, to contemporary China, I discuss how this masculine icon has been transformed from one of heroic rebellion to one of existential isolation. Indeed, as the politics of both the outmoded Confucian family and fractured Chinese nationhood intersect, what the sad young (gay) man rebels against is a political fluctuation which is no longer fixed; as the young man's opposition is no longer fixed, so too does he become alienated even from his own rebellious cause.

The aspartic proteinase from the rodent parasite Plasmodium berghei as a potential model for plasmepsins from the human malaria parasite, Plasmodium falciparum

The gene encoding an aspartic proteinase precursor (proplasmepsin) from the rodent malaria parasite Plasmodium berghei has been cloned. Recombinant P. berghei plasmepsin hydrolysed a synthetic peptide substrate and this cleavage was prevented by the general aspartic proteinase inhibitor, isovaleryl pepstatin and by Ro40-4388, a lead compound for the inhibition of plasmepsins from the human malaria parasite Plasmodium falciparum. Southern blotting detected only one proplasmepsin gene in P. berghei. Two plasmepsins have previously been reported in P. falciparum. Here, we describe two further proplasmepsin genes from this species. The suitability of P. berghei as a model for the in vivo evaluation of plasmepsin inhibitors is discussed.

How many adolescents start smoking each day in the United States?

PURPOSE

To provide daily estimates of first experimentation and attainment of established smoking in adolescents 11-17 years of age.

METHODS

The 1989 and 1993 Teenage Attitudes and Practices Surveys (TAPS) (16,954 observations) was used to estimate rates in 1991 for: (a) first experimentation (even a few puffs), and (b) established smoking (reaching a lifetime level of at least 100 cigarettes). The 1992 and 1993 Current Population Surveys (CPS) (82,279 adults) allowed calculation of year-specific initiation rates (1980-1989) from the age respondents reported as having started smoking "fairly regularly." Rates were applied to Census data for the appropriate years to yield numbers accruing each day. Estimates were calculated for adolescents (11- to 17-year-olds) and youth (11- to 20-year-olds).

RESULTS

For TAPS, in 1991, 4824 adolescents first tried cigarettes and 1975 became established smokers each day. Considering all youth, these estimates increase to 5497/day for first experimentation and to 2933/day for established smokers. For CPS, from 1980 to 1989, around 2300 adolescents initiated fairly regular smoking each day. For all youth, the estimate has increased to about 3400/day.

CONCLUSIONS

Because approximately 4800 adolescents and 5500 youth appear to be experimenting with cigarettes for the first time each day, and close to 3000 youth become established smokers daily, increased prevention efforts are clearly justified.

A hookworm allergen which strongly resembles calreticulin

Immmoglobulin E-rich plasma from patients from Papua New Guinea infected with Necator americanus has been used to probe an adult N. americanus cDNA library for the presence of hookworm allergens. Using this approach, one hookworm allergen has been identified as calreticulin, which was subsequently expressed in Escherichia coli. Little serological cross reactivity was seen between the recombinant calreticulins of this hookworm and its host. Prospective roles for hookworm calreticulin in the host-parasite relationship are discussed in depth.

A review of quality-of-life evaluations in patients with congestive heart failure

The factors that may lead to an impaired quality of life in congestive heart failure (CHF) are physical symptoms, psychological problems, treatment adverse effects and social limitation. There are now several general and disease-specific quality-of-life (QOL) questionnaires which have been used to measure treatment effects in clinical trials in CHF. We review the design and validation of both generic and disease-specific QOL questionnaires which have been used in clinical trials in CHF. We then evaluate the performance of these QOL questionnaires in recent clinical trials in CHF in relation to other outcome measures. We conclude that there are important differences between these QOL questionnaires. The choice of a QOL questionnaire is relevant to both patient compliance and clinical outcomes in CHF trials. The 36-Item Short Form (SF-36) Health Survey, a generic QOL questionnaire, and the Minnesota Living with Heart Failure questionnaire, a disease-specific QOL questionnaire, have returned informative data in most trials in which they have been used. QOL questionnaires require further development if this important outcome is to be reliably measured in future clinical trials in CHF.