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Introduction: The ζ subunit is a potent inhibitor of the F 1 F O -ATPase of Paracoccus denitrificans (PdF 1 F O -ATPase) and related α -proteobacteria different from the other two canonical inhibitors of bacterial ( ε ) and mitochondrial (IF 1 ) F 1 F O -ATPases. ζ mimics mitochondrial IF 1 in its inhibitory N-terminus, blocking the PdF 1 F O -ATPase activity as a unidirectional pawl-ratchet and allowing the PdF 1 F O -ATP synthase turnover. ζ is essential for the respiratory growth of P. denitrificans , as we showed by a Δζ knockout. Given the vital role of ζ in the physiology of P. denitrificans , here, we assessed the evolution of ζ across the α -proteobacteria class. Methods: Through bioinformatic, biochemical, molecular biology, functional, and structural analyses of several ζ subunits, we confirmed the conservation of the inhibitory N-terminus of ζ and its divergence toward its C-terminus. We reconstituted homologously or heterologously the recombinant ζ subunits from several α -proteobacteria into the respective F-ATPases, including free-living photosynthetic, facultative symbiont, and intracellular facultative or obligate parasitic α-proteobacteria. Results and discussion: The results show that ζ evolved, preserving its inhibitory function in free-living α-proteobacteria exposed to broad environmental changes that could compromise the cellular ATP pools. However, the ζ inhibitory function was diminished or lost in some symbiotic α-proteobacteria where ζ is non-essential given the possible exchange of nutrients and ATP from hosts. Accordingly, the ζ gene is absent in some strictly parasitic pathogenic Rickettsiales, which may obtain ATP from the parasitized hosts. We also resolved the NMR structure of the ζ subunit of Sinorhizobium meliloti (Sm- ζ ) and compared it with its structure modeled in AlphaFold. We found a transition from a compact ordered non-inhibitory conformation into an extended α-helical inhibitory N-terminus conformation, thus explaining why the Sm- ζ cannot exert homologous inhibition. However, it is still able to inhibit the PdF 1 F O -ATPase heterologously. Together with the loss of the inhibitory function of α-proteobacterial ε , the data confirm that the primary inhibitory function of the α-proteobacterial F 1 F O -ATPase was transferred from ε to ζ and that ζ, ε, and IF 1 evolved by convergent evolution. Some key evolutionary implications on the endosymbiotic origin of mitochondria, as most likely derived from α -proteobacteria, are also discussed., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Mendoza-Hoffmann, Yang, Buratto, Brito-Sánchez, Garduño-Javier, Salinas-López, Uribe-Álvarez, Ortega, Sotelo-Serrano, Cevallos, Ramírez-Silva, Uribe-Carvajal, Pérez-Hernández, Celis-Sandoval and García-Trejo.)

The F1FO-ATP synthase nanomotor synthesizes >90% of the cellular ATP of almost all living beings by rotating in the “forward” direction, but it can also consume the same ATP pools by rotating in “reverse.” To prevent futile F1FO-ATPase activity, several different inhibitory proteins or domains in bacteria (ε and ζ subunits), mitochondria (IF1), and chloroplasts (ε and γ disulfide) emerged to block the F1FO-ATPase activity selectively. In this study, we analyze how these F1FO-ATPase inhibitory proteins have evolved. The phylogeny of the α-proteobacterial ε showed that it diverged in its C-terminal side, thus losing both the inhibitory function and the ATP-binding/sensor motif that controls this inhibition. The losses of inhibitory function and the ATP-binding site correlate with an evolutionary divergence of non-inhibitory α-proteobacterial ε and mitochondrial δ subunits from inhibitory bacterial and chloroplastidic ε subunits. Here, we confirm the lack of inhibitory function of wild-type and C-terminal truncated ε subunits of P. denitrificans. Taken together, the data show that ζ evolved to replace ε as the primary inhibitor of the F1FO-ATPase of free-living α-proteobacteria. However, the ζ inhibitory function was also partially lost in some symbiotic α-proteobacteria and totally lost in some strictly parasitic α-proteobacteria such as the Rickettsiales order. Finally, we found that ζ and IF1 likely evolved independently via convergent evolution before and after the endosymbiotic origin mitochondria, respectively. This led us to propose the ε and ζ subunits as tracer genes of the pre-endosymbiont that evolved into the actual mitochondria.

Inorganic pyrophosphatases are divided in two families, which differ both in structure and mechanism. All of them incorporate in its structure divalent metal cations. In 2003, it was reported for the first time that Rhodobacter capsulatus cytoplasmic pyrophosphatase belongs to family II. It is expected then, that this enzyme contains metal elements in its structure; however, this characterization has not been carried out yet. A fine application of accelerators is the use of proton beams to induce X-ray emission (PIXE) for analyzing the composition of biological macromolecules. The purpose of this work is to complement R. capsulatus cytoplasmic pyrophosphatase characterization by determining the presence of metal elements in its structure. Three different strategies were used: PAGE-PIXE, PAGE-Digestion-PIXE, and Dialysis-PIXE and when metals were found the metal/enzyme ratio was calculated. Only cobalt was found to be associated to the enzyme chemical structure in a ratio 3 Co/enzyme., (Copyright © 2010 Elsevier B.V. All rights reserved.)

The F(1)F(O) and F(1)-ATPase complexes of Paracoccus denitrificans were isolated for the first time by ion exchange, gel filtration, and density gradient centrifugation into functional native preparations. The liposome-reconstituted holoenzyme preserves its tight coupling between F(1) and F(O) sectors, as evidenced by its high sensitivity to the F(O) inhibitors venturicidin and diciclohexylcarbodiimide. Comparison and N-terminal sequencing of the band profile in SDS-PAGE of the F(1) and F(1)F(O) preparations showed a novel 11-kDa protein in addition to the 5 canonical alpha, beta, gamma, delta, and epsilon subunits present in all known F(1)-ATPase complexes. BN-PAGE followed by 2D-SDS-PAGE confirmed the presence of this 11-kDa protein bound to the native F(1)F(O)-ATP synthase of P. denitrificans, as it was observed after being isolated. The recombinant 11 kDa and epsilon subunits of P. denitrificans were cloned, overexpressed, isolated, and reconstituted in particulate F(1)F(O) and soluble F(1)-ATPase complexes. The 11-kDa protein, but not the epsilon subunit, inhibited the F(1)F(O) and F(1)-ATPase activities of P. denitrificans. The 11-kDa protein was also found in Rhodobacter sphaeroides associated to its native F(1)F(O)-ATPase. Taken together, the data unveil a novel inhibitory mechanism exerted by this 11-kDa protein on the F(1)F(O)-ATPase nanomotor of P. denitrificans and closely related alpha-proteobacteria.

Blood pressure-lowering therapy reduces left ventricular mass, but the question of whether differences exist among drug classes has not been fully resolved. Our aim was to compare the effects of diuretics, beta-blockers, calcium channel blockers, angiotensin-converting enzyme inhibitors, and angiotensin receptor blockers on left ventricular mass regression in patients with hypertension on the basis of prospective, randomized comparative studies. We performed meta-analyses, involving pooled pairwise comparisons of the drug classes and of each class versus other classes statistically combined, and meta-regression analyses to identify the determinants of the regression. The 75 relevant publications involved 84 pairwise comparisons and 6001 patients. Regression of left ventricular mass was significantly less (P=0.01) with beta-blockers (9.8%) than with angiotensin receptor blockers (12.5%), but none of the other analyzable pairwise comparisons between drug classes revealed significant differences (P>0.10). In addition, beta-blockers showed less regression than the other 4 classes statistically combined (P<0.01), and regression was more pronounced with angiotensin receptor blockers versus the others (P<0.01). In multivariable meta-regression analysis on all of the treatment arms, beta-blocker treatment was a significant and negative predictor of the regression (-3.6%; P<0.01), but this was not the case for the other drug classes, including angiotensin receptor blockers. In conclusion, beta-blockers show less regression of left ventricular mass, whereas angiotensin receptor blockers may induce larger regression. The inferiority of beta-blockers appears to be more convincing than the superiority of angiotensin receptor blockers.

Our aim was to assess the prognostic significance of nighttime and daytime ambulatory blood pressure and their ratio for mortality and cause-specific cardiovascular events in hypertensive patients without major cardiovascular disease at baseline. We performed a meta-analysis on individual data of 3468 patients from 4 prospective studies performed in Europe. Age of the subjects averaged 61+/-13 years, 45% were men, 13.7% smoked, 8.4% had diabetes, and 61% were under antihypertensive treatment at the time of ambulatory blood pressure monitoring. Office, daytime, and nighttime blood pressure averaged 159+/-20/91+/-12, 143+/-17/87+/-12, and 130+/-18/75+/-12 mm Hg. Total follow-up amounted to 23 164 patient-years. We used multivariable Cox regression analysis to assess the hazard ratios associated with 1 standard deviation higher blood pressure. Daytime and nighttime systolic blood pressure predicted all-cause and cardiovascular mortality, coronary heart disease, and stroke, independently from office blood pressure and confounding variables. When these blood pressures were entered simultaneously into the models, nighttime blood pressure predicted all outcomes, whereas daytime blood pressure did not add prognostic precision to nighttime pressure. Appropriate interaction terms indicated that the results were similar in men and women, in younger and older patients, and in treated and untreated patients The systolic night-day blood pressure ratio predicted all outcomes, which only persisted for all-cause mortality after adjustment for 24-hour blood pressure. In conclusion, nighttime blood pressure is in general a better predictor of outcome than daytime pressure in hypertensive patients, and the night-day blood pressure ratio predicts mortality, even after adjustment for 24-hour blood pressure.

Amphipterygium adstringens (Schltdl.) Standl. (Anacardiaceae) is widely used in traditional Mexican medicine for the treatment of gastritis and ulcers. In this work, we studied the anti-Helicobacter pylori activity of its bark, this Gram-negative bacterium is considered the major etiological agent of chronic active gastritis and peptic ulcer disease, and it is linked to gastric carcinoma. From a bio-guided assay of the fractions obtained form a continuous Soxhlet extraction of the bark, we identified that petroleum ether fraction had significant antimicrobial activity against Helicobacter pylori. From this fraction, we isolated an anacardic acids mixture and three known triterpenes: masticadienonic acid; 3alpha-hydroxymasticadienonic acid; 3-epi-oleanolic; as well as the sterol beta-sitosterol. Only the anacardic acids mixture exhibits a potent dose-dependent antibacterial activity (MIC=10 microg/ml in broth cultures). It is enriched in saturated alkyl phenolic acids (C15:0, C16:0, C17:0 C19:0) which represents a novel source of these compounds with potent anti-Helicobacter pylori activity. The promising use of anacardic acids and Amphipterygium adstringens bark in the development of an integral treatment of Helicobacter pylori diseases is discussed.

Background: It has been suggested that low diastolic blood pressure (BP) while receiving antihypertensive treatment (hereinafter called on-treatment BP) is harmful in older patients with systolic hypertension. We examined the association between on-treatment diastolic BP, mortality, and cardiovascular events in the prospective placebo-controlled Systolic Hypertension in Europe Trial., Methods: Elderly patients with systolic hypertension were randomized into the double-blind first phase of the trial, after which all patients received active study drugs (phase 2). We assessed the relationship between outcome and on-treatment diastolic BP by use of multivariate Cox regression analysis during receipt of placebo (phase 1) and during active treatment (phases 1 and 2)., Results: Rates of noncardiovascular mortality, cardiovascular mortality, and cardiovascular events were 11.1, 12.0, and 29.4, respectively, per 1000 patient-years with active treatment (n = 2358) and 11.9, 12.6, and 39.0, respectively, with placebo (n = 2225). Noncardiovascular mortality, but not cardiovascular mortality, increased with low diastolic BP with active treatment (P < .005) and with placebo (P < .05); for example, hazard ratios for lower diastolic BP, that is, 65 to 60 mm Hg, were, respectively, 1.15 (95% confidence interval, 1.00-1.31) and 1.28 (95% confidence interval, 1.03-1.59). Low diastolic BP with active treatment was associated with increased risk of cardiovascular events, but only in patients with coronary heart disease at baseline (P < .02; hazard ratio for BP 65-60 mm Hg, 1.17; 95% confidence interval, 0.98-1.38)., Conclusions: These findings support the hypothesis that antihypertensive treatment can be intensified to prevent cardiovascular events when systolic BP is not under control in older patients with systolic hypertension, at least until diastolic BP reaches 55 mm Hg. However, a prudent approach is warranted in patients with concomitant coronary heart disease, in whom diastolic BP should probably not be lowered to less than 70 mm Hg.

Background: Cadmium is a ubiquitous environmental pollutant, which accumulates in the human body such that 24-h urinary excretion is a biomarker of lifetime exposure. We aimed to assess the association between environmental exposure to cadmium and cancer., Methods: We recruited a random population sample (n=994) from an area close to three zinc smelters and a reference population from an area with low exposure to cadmium. At baseline (1985-89), we measured cadmium in urine samples obtained over 24 h and in the soil of participants' gardens, and followed the incidence of cancer until June 30, 2004. We used Cox regression to calculate hazard ratios for cancer in relation to internal (ie, urinary) and external (ie, soil) exposure to cadmium, while adjusting for covariables., Findings: Cadmium concentration in soil ranged from 0.8 mg/kg to 17.0 mg/kg. At baseline, geometric mean urinary cadmium excretion was 12.3 nmol/day for people in the high-exposure area, compared with 7.7 nmol/day for those in the reference (ie, low-exposure) area (p<0.0001). During follow-up (median 17.2 years [range 0.6-18.8]), 50 fatal cancers and 20 non-fatal cancers occurred, of which 18 and one, respectively, were lung cancers. Overall cancer risk was significantly associated with a doubling of 24-h cadmium excretion (hazard ratio 1.31 [95% CI 1.03-1.65], p=0.026. Population-attributable risk of lung cancer was 67% (95% CI 33-101) in the high-exposure area, compared with that of 73% (38-108) for smoking. For lung cancer, adjusted hazard ratio was 1.70 (1.13-2.57, p=0.011) for a doubling of 24-h urinary cadmium excretion, 4.17 (1.21-14.4, p=0.024) for residence in the high-exposure area versus the low-exposure area, and 1.57 (1.11-2.24, p=0.012) for a doubling of cadmium concentration in soil., Interpretation: Historical pollution from non-ferrous smelters continues to present a serious health hazard, necessitating targeted preventive measures.

Experimental evidence and observations in humans strongly support an interactive role of mutated alpha-adducin, sodium (Na(+))/potassium (K(+))-adenosine triphosphatase (ATPase) activity and endogenous ouabain in Na(+) homeostasis and the pathogenesis of hypertension. The Ouabain and Adducin for Specific Intervention on Sodium in HyperTension (OASIS-HT) trial is an early Phase II dose-finding study, which will be conducted across 39 European centers. Following a run-in period of 4 weeks without treatment, eligible patients will be randomized to one of five oral doses of rostafuroxin consisting of 0.05, 0.15, 0.5, 1.5, or 5.0 mg/day. Each dose will be compared to a placebo in a double-blind crossover experiment with balanced randomization. Treatment will be initiated with the active drug and continued with placebo or vice versa. Each double-blind period will last 5 weeks. The primary end point is the reduction in systolic blood pressure defined as the average of three clinic readings with the patient in the sitting position. Secondary end points include the reduction in diastolic blood pressure on clinic measurement, the decrease in the 24-h blood pressure, and the incidence of end points related to safety. Secondary objectives are to investigate the dependence of the blood pressure-lowering activity on the plasma concentration of endogenous ouabain and the genetic variation of the enzymes involved in the metabolism of this hormone, and the adducin cytoskeleton proteins. Eligible patients will have Grade I or II systolic hypertension without associated conditions and no more than two additional risk factors. In conclusion, OASIS-HT is a combination of five concurrent crossover studies, one for each dose of rostafuroxin to be studied. To our knowledge, OASIS-HT is the first Phase II dose-finding study in which a genetic hypothesis is driving primary and secondary end points.

To be suitable for the management of hypertension, self-measurement of blood pressure (BP) at home should follow international recommendations. The use of accurate and validated measuring devices is an important prerequisite. Upper arm BP monitors are the first choice, while wrist and finger devices cannot be recommended. Measurements should, preferentially, be downloaded from the memory of a device or printed. Reference values have been proposed, but were mostly based on cross-sectional observations and have not yet been widely validated by prospective outcome studies. Currently, levels of home BP of <135 mm Hg systolic and 85 mm Hg diastolic are usually considered normal. Home BP measurement is sometimes recommended as an alternative to ambulatory BP monitoring to diagnose white-coat hypertension.However, home BP measurement cannot replace ambulatory BP monitoring in the diagnosis of hypertension (white-coat), but both techniques have complementary roles. The appropriateness of home BP measurement to guide antihypertensive treatment has only been tested in one large-scale randomized trial: the THOP (Treatment of Hypertension Based on Home or Office Blood Pressure) trial. The THOP trial showed that antihypertensive treatment based on home instead of office BP led to less intensive drug treatment, but also to less BP control with no differences in general wellbeing and left ventricular mass. Home BP monitoring also contributed to the identification of patients with white-coat hypertension. On balance, most evidence supports the view that office BP measurement remains the key in the diagnosis and treatment of hypertension. Treatment can be started without confirmation of elevated office BP in patients with high office BP and target organ damage, or a high cardiovascular risk profile. In patients with raised office BP but without target organ damage (white-coat hypertension), or with normal office BP but unexplained target organ damage (masked hypertension), ambulatory or home BP monitoring or both must be used to confirm the diagnosis. Few longitudinal studies have addressed the long-term prognostic meaning of home BP measurement. Until more prospective data become available, management of hypertension exclusively based on self-measurement of BP at home cannot be recommended.

Objective and Methods: In this randomized clinical trial, conducted in 400 hypertensive patients [sitting diastolic blood pressure (DBP) >95 mmHg], blood pressure-lowering therapy was adjusted in a stepwise manner, either on the basis of the self-measured DBP at home or on the basis of conventional DBP measured at the doctor's office., Results: Therapy guided by home blood pressure instead of office blood pressure led to less intensive drug treatment and marginally lower costs, but also to less blood pressure control with no differences in left ventricular mass. Self-measurement helped to identify patients with white-coat hypertension., Conclusions: The present findings support a stepwise strategy for the evaluation of blood pressure, in which self-measurement and ambulatory monitoring are complementary to conventional office blood pressure measurement.

The physiological role of the membrane-bound pyrophosphatase of Rhodospirillum rubrum was investigated by the characterization of a mutant strain. Comparisons of growth levels between the wild type and the mutant under different low-potential conditions and during transitions between different metabolisms indicate that this enzyme provides R. rubrum with an alternative energy source that is important for growth in low-energy states.

White-coat hypertension (WCHT), also called 'isolated office or clinic hypertension', is defined as the occurrence of blood pressure (BP) values higher than normal when measured in the medical environment, but within the normal range during daily life, usually defined as average daytime ambulatory BP (ABP) or home BP values (<135 mm Hg systolic and <85 mm Hg diastolic). The prevalence of WCHT varies from 15% to over 50% of all patients with mildly elevated office BP (OBP) values. In untreated hypertensive patients, the probability of WCHT especially increases with female gender and a mildly elevated OBP level. The value of other possible determinants such as (non) smoking status, duration of hypertension, left ventricular mass, number of OBP measurements, educational level, etc. is less consistently shown. Although, for various reasons, studies evaluating the long-term effects of WCHT are not always easy to interpret, most data indicate that persons with WCHT have a worse or equal cardiovascular prognosis than normotensives, but a better one than those with sustained hypertension. WCHT is sometimes considered a prehypertensive state, but data on the long-term evolution of subjects with WCHT are scarce. Patients with WCHT and a high cardiovascular risk or proven target organ damage should be pharmacologically treated. Subjects with uncomplicated WCHT should probably not receive medical therapy, but a close follow-up, including regular assessment of other risk factors and measurement of OBP (every 6 months) and ABP (every 1 or 2 years), is warranted.

The aim of the present study was to assess the prognostic value of ECG voltages at baseline and their serial changes during follow-up in a large prospective study with standardized follow-up and strictly defined end points. Patients who were 60 years old or older, with systolic blood pressure of 160 to 219 mm Hg and diastolic pressure <95 mm Hg, were randomized into the double-blind placebo-controlled Systolic Hypertension in Europe trial. Active treatment consisted of nitrendipine, which could be combined with or replaced by enalapril, hydrochlorothiazide, or both. At the end of the double-blind part of the trial (median follow-up, 2.0 years), follow-up was extended and all patients received active study drugs (median total follow-up, 6.1 years). Electrocardiography was performed at baseline and yearly thereafter. Electrocardiographic left ventricular mass was prospectively defined as the sum of 3 voltages (RaVL+SV1+RV5), which averaged 3.1+/-1.0 mV. The adjusted relative hazard rate, associated with a 1 mV higher sum at baseline, amounted to 1.10 and 1.15 for all-cause and cardiovascular mortality and to 1.21 and 1.18 for strokes and cardiac events, respectively (P< or =0.01 for all). A 1-mV decrease in electrocardiographic voltages during follow-up independently predicted a lower incidence of cardiac events (relative hazard rate: 0.86; P< or =0.05), but not of stroke or mortality. In conclusion, electrocardiographic voltages at baseline and their serial changes during follow-up predict subsequent events in older patients with systolic hypertension.

Background: To assess the impact of immediate versus delayed antihypertensive treatment on the outcome of older patients with isolated systolic hypertension, we extended the double-blind placebo-controlled Systolic Hypertension in Europe (Syst-Eur) trial by an open-label follow-up study lasting 4 years., Methods: The Syst-Eur trial included 4695 randomized patients with minimum age of 60 years and an untreated blood pressure of 160-219 mmHg systolic and below 95 mmHg diastolic. The double-blind trial ended after a median follow-up of 2.0 years (range 1-97 months). Of 4409 patients still alive, 3517 received open-label treatment consisting of nitrendipine (10-40 mg daily) with the possible addition of enalapril (5-20 mg daily), hydrochlorothiazide (12.5-25 mg daily), or both add-on drugs. Non-participants (n = 892) were also followed up., Results: Median follow-up increased to 6.1 years. Systolic pressure decreased to below 150 mmHg (target level) in 2628 participants (75.0%). During the 4-year open-label follow-up, stroke and cardiovascular complications occurred at similar frequencies in patients formerly randomized to placebo and those continuing active treatment. These rates were similar to those previously observed in the active-treatment group during the double-blind trial. Considering the total follow-up of 4695 randomized patients, immediate compared with delayed antihypertensive treatment reduced the occurrence of stroke and cardiovascular complications by 28% (P = 0.01) and 15% (P = 0.03), respectively, with a similar tendency for total mortality (13%, P = 0.09). In 492 diabetic patients, the corresponding estimates of long-term benefit (P < 0.02) were 60, 51 and 38%, respectively., Conclusions: Antihypertensive treatment can achieve blood pressure control in most older patients with isolated systolic hypertension. Immediate compared with delayed treatment prevented 17 strokes or 25 major cardiovascular events per 1000 patients followed up for 6 years. These findings underscore the necessity of early treatment of isolated systolic hypertension.

Context: Self-measurement of blood pressure is increasingly used in clinical practice, but how it affects the treatment of hypertension requires further study., Objective: To compare use of blood pressure (BP) measurements taken in physicians' offices and at home in the treatment of patients with hypertension., Design, Setting, and Participants: Blinded randomized controlled trial conducted from March 1997 to April 2002 at 56 primary care practices and 3 hospital-based outpatient clinics in Belgium and 1 specialized hypertension clinic in Dublin, Ireland. Four hundred participants with a diastolic BP (DBP) of 95 mm Hg or more as measured at physicians' offices were enrolled and followed up for 1 year., Interventions: Antihypertensive drug treatment was adjusted in a stepwise fashion based on either the self-measured DBP at home (average of 6 measurements per day during 1 week; n = 203) or the average of 3 sitting DBP readings at the physician's office (n = 197). If the DBP guiding treatment was above (>89 mm Hg), at (80-89 mm Hg), or below (<80 mm Hg) target, a physician blinded to randomization intensified antihypertensive treatment, left it unchanged, or reduced it, respectively., Mean Outcome Measures: Office and home BP levels, 24-hour ambulatory BP, intensity of drug treatment, electrocardiographic and echocardiographic left ventricular mass, symptoms reported by questionnaire, and costs of treatment., Results: At the end of the study (median follow-up, 350 days; interquartile range, 326-409 days), more home BP than office BP patients had stopped antihypertensive drug treatment (25.6% vs 11.3%; P<.001) with no significant difference in the proportions of patients progressing to multiple-drug treatment (38.7% vs 45.1%; P =.14). The final office, home, and 24-hour ambulatory BP measurements were higher (P<.001) in the home BP group than in the office BP group. The mean baseline-adjusted systolic/diastolic differences between the home and office BP groups averaged 6.8/3.5 mm Hg, 4.9/2.9 mm Hg, and 4.9/2.9 mm Hg, respectively. Left ventricular mass and reported symptoms were similar in the 2 groups. Costs per 100 patients followed up for 1 month were only slightly lower in the home BP group (3875 vs 3522 [4921 dollars vs 4473 dollars]; P =.04)., Conclusions: Adjustment of antihypertensive treatment based on home BP instead of office BP led to less intensive drug treatment and marginally lower costs but also to less BP control, with no differences in general well-being or left ventricular mass. Self-measurement allowed identification of patients with white-coat hypertension. Our findings support a stepwise strategy for the evaluation of BP in which self-measurement and ambulatory monitoring are complementary to conventional office measurement and highlight the need for prospective outcome studies to establish the normal range of home-measured BP.

Amphotericin B is an antibiotic that forms ion channels in the membrane of a host cell. The change in permeability produced by these channels is greatly improved by sterols; nevertheless, the single channel conductivity remains invariant. Hence, it is proposed that sterols do not act directly, but rather through the modulation of the membrane phase. We look at the formation of these channels in the bacterial membrane to determine the mechanism of its known antibiotic resistance. We found that channels can indeed be formed in this membrane, but a substantial amount of amphotericin B is required. We also study the effects of the antibiotic concentration needed for channel expression as well as the dynamics of channels affected by both sterol and temperature in phosphatidylcholine membranes. The results support the idea that membrane structure is a determining factor in the action of the antibiotic.

The cytoplasmic pyrophosphatase of the photosynthetic bacterium Rhodospirillum rubrum was purified to electrophoretic homogeneity. The enzyme is a homohexamer of 20-kDa monomers. The gene was cloned and sequenced. Alignment of the deduced 179-amino-acid protein with known bacterial pyrophosphatases revealed conservation of all residues in the active site. Attempts to obtain an insertion mutant of the cytoplasmic pyrophosphatase gene did not yield any cell completely devoid of cytoplasmic pyrophosphatase activity. The mutants obtained showed 50% of the enzymatic activity and grew in twice the generation time of wild-type cells. This suggests that the membrane-bound pyrophosphatase of Rsp. rubrum is not sufficient for a normal growth rate, whereas the cytoplasmic enzyme is essential for growth. The characteristics of the gene and the encoded protein fit those of prokaryotic family I pyrophosphatases.

The cytoplasmic pyrophosphatase from Rhodobacter sphaeroides was purified and characterized. The enzyme is a homodimer of 64 kDa. The N-terminus was sequenced and used to obtain the complete pyrophosphatase sequence from the preliminary genome sequence of Rba. sphaeroides, showing extensive sequence similarity to family II or class C pyrophosphatases. The enzyme hydrolyzes only Mg-PP(i) and Mn-PP(i) with a K(m) of 0.35 mM for both substrates. It is not activated by free Mg (2+), in contrast to the cytoplasmic pyrophosphatase from Rhodospirillum rubrum, and it is not inhibited by NaF, methylendiphosphate, or imidodiphosphate. This work shows that Rba. sphaeroides and Rhodobacter capsulatus cytoplasmic pyrophosphatases belong to family II, in contrast to Rsp. rubrum, Rhodopseudomonas palustris, Rhodopseudomonas gelatinosa, and Rhodomicrobium vannielii cytoplasmic pyrophosphatases which should be classified as members of family I. This is the first report of family II cytoplasmic pyrophosphatases in photosynthetic bacteria and in a gram-negative organism.