Effect of long-term hormone replacement therapy on angiotensin-converting enzyme activity and bradykinin in postmenopausal women with essential hypertension and normotensive postmenopausal women

OBJECTIVE

Hormone replacement therapy (HRT) reduces the incidence of cardiovascular disease in postmenopausal women. Three-month short-term HRT in postmenopausal women with essential hypertension increased the plasma concentrations ofbradykinin with decreased serum angiotensin-converting enzyme (ACE) activity, which may be partially responsible for the cardioprotective effects of HRT. The objective was to determine whether 12-month long-term HRT in postmenopausal women with essential hypertension would maintain the decreased ACE activity and increased bradykinin levels and whether long-term HRT would increase the plasma bradykinin concentrations of normotensive postmenopausal women who had shown no significant changes in the 3-month HRT study, despite their decreased serum ACE activity.

DESIGN

Twenty hypertensive and 15 normotensive postmenopausal women were treated with conjugated estrogens (0.625 mg/day) and medroxyprogesterone (2.5 mg/day) for 12 months. Twenty hypertensive and 15 normotensive postmenopausal women were used as controls. The controls were not treated with HRT. Serum ACE activity and plasma bradykinin concentrations were measured at baseline and at 12 months.

RESULTS

Long-term HRT in both hypertensive and normotensive postmenopausal women significantly decreased serum ACE activity from 15.5+/-0.7 IU/L and 16.0+/-0.9 IU/L, respectively, at baseline to 13.3+/-0.5 IU/L and 14.2+/-0.9 IU/L, respectively, 12 months after the start of HRT (p < 0.05 and p < 0.05, respectively). Long-term HRT in both hypertensive and normotensive postmenopausal women also significantly increased plasma bradykinin concentrations from 22.1+/-4.4 pg/mL and 19.2+/-3.0 pg/mL, respectively, at baseline to 86.7+/-21.2 pg/mL and 73.5+/-23.0 pg/mL, respectively, 12 months after the start of HRT (p < 0.01 and p < 0.05, respectively). No significant changes in serum ACE activity or plasma bradykinin concentrations were observed in the control groups.

CONCLUSIONS

Long-term HRT in hypertensive and normotensive postmenopausal women decreases their serum ACE activity and increases their plasma bradykinin concentrations. Thus, maintenance of elevated bradykinin with decreased serum ACE activity by HRT may be useful in reducing the risk of cardiovascular disease in both hypertensive and normotensive postmenopausal women.

[Hormone replacement therapy and vascular function]

Hormone replacement therapy (HRT) by estrogen has a cardioprotective effect in postmenopausal women. This effect results partly from the direct actions of estrogen on vascular receptors. These are mainly endothelium-dependent or endothelium-independent vascular relaxing effects. Increases in prostacyclin and bradykinin, and a decrease in endothelin-1 by estrogen are involved.

Small-angle X-ray scattering analysis of stearic acid modified lipase

Stearic acid modified lipase (from Rhizopus japonicus) exhibited remarkable interesterification activity in n-hexane, but crude native lipase did not. The structure of the fatty acid modified lipase had not been analyzed until now. We analyzed the modified lipase by small-angle X-ray scattering (SAXS) measurements in order to clarify the structure. SAXS measurements showed that the modified lipase consisted of a lipid lamellar structure and implied that the lipase was incorporated into the lamellar structure of stearic acid. The long spacings in the lamellar structures of the modified lipase and stearic acid were measured.

[Characteristics of heterosexually acquired AIDS in Japan. An inter-country comparison using AIDS Surveillance data]

OBJECTIVES

To identify epidemiological characteristics of heterosexually acquired AIDS in Japan, with emphasis on potential influence on future trends.

METHODS

National AIDS Surveillance data in Japan were compared with those in the UK and US, where detailed information is available from well-established surveillance procedures. Data on AIDS cases diagnosed until the end of 1996, particularly those acquired heterosexually, were analyzed by year of diagnosis, gender and age group.

RESULTS

The number of heterosexually acquired AIDS cases in Japan has continued to increase, while those in the UK and US leveled out or decreased recently. The increase during a two-year period after reaching a certain number of cases per year was found to be 2.3-fold in Japanese, 2.4-fold in UK whites and 5-fold in US whites. The male to female ratio (M/F) for heterosexually acquired AIDS was 6.3 among Japanese, while the ratio was 1.1 and 0.5 in the UK and US, respectively. The age distribution at AIDS diagnosis demonstrated a peak from 35 to 54 years of age among Japanese males, as compared to 30 to 34 among males in the UK and the US. No significant difference was apparent in the age distribution among females in the three countries.

CONCLUSIONS

The relatively small number of AIDS cases in Japan is attributable to the late introduction of HIV and the limited chance of heterosexual transmission from homosexual/bisexual men and injecting drug users. In addition, transmission has probably most often occurred between middle-aged Japanese males and non-Japanese females. As there is a growing risk of HIV infection among Japanese females and young Japanese males, new prevention strategies targeting these groups are urgently required.

Hormone replacement therapy increases plasma level of angiotensin II in postmenopausal hypertensive women

The renin-angiotensin-aldosterone system plays a major role in the pathogenesis of hypertension by enhancing the production or the activity of angiotensin II (ANG II). We evaluated the effects of hormone replacement therapy (HRT) on the renin-angiotensin-aldosterone system and on bradykinin in postmenopausal women (PMW) who were hypertensive or normotensive. Subjects included 28 PMW whose elevated blood pressure (BP) was well controlled on antihypertensive agents excluding diuretics, angiotensin-converting enzyme (ACE) inhibitors, and ANG II receptor antagonists. As controls, we evaluated 16 normotensive PMW. All subjects received oral HRT daily for 6 months. The plasma levels of angiotensin I (ANG I), ANG II, and bradykinin as well as plasma renin activity (PRA) showed a significant increase in HRT in the hypertensive group, but not in the normotensive group. The serum ACE activity showed a significant decrease in both groups, but the plasma level of aldosterone was unchanged. Despite the decrease in serum ACE activity, there was an increase in the plasma ANG II level. Hormone replacement therapy increased the level of ANG II in the hypertensive women, but their BP was unaffected. The increase in plasma bradykinin level may maintain homeostasis in the presence of an increase in plasma ANG II, which is a risk factor for cardiovascular disease. Hormone replacement therapy was associated with a decrease in serum ACE and an increase in plasma bradykinin in hypertensive PMW. Accordingly, the protective effect of HRT against cardiovascular disease in PMW can be provided by a decrease in ACE activity and an increase in bradykinin.

Asymptomatic case of congenital absence of the gallbladder

Congenital absence of the gallbladder is rare among biliary abnormalities, and its preoperative diagnosis has been considered very difficult. We encountered a patient with congenital absence of the gallbladder and suggest a possible preoperative diagnosis of the abnormality, as well as reviewing the literature.

[Inferior mini-sternotomy for off-pump CABG using bilateral internal thoracic arteries]

Case 1: A 72-year-old woman with effort angina underwent coronary artery bypass grafting. A preoperative coronary angiogram showed 90% stenosis in the proximal main RCA, and total occlusion in the proximal LAD, distal of which was an area well supplied by collaterals from the RCA. This patient had previously undergone right upper lobectomy due to lung cancer. With a skin incision of 8 cm, the LITA was inserted into the LAD and the RITA was inserted into the mid RCA through an inferior mini-sternotomy while the heart was beating. Case 2: A 69-year-old man with effort angina underwent CABG. A preoperative coronary angiogram showed 90% stenosis in the proximal main RCA, 75% stenosis in the PDA and total occlusion in the proximal LAD, distal of which was an area well supplied by collaterals from the RCA. With a skin incision of 11 cm, the LITA was inserted into the LAD, the RITA into the mid-RCA and the radial artery graft attached to the RITA was grafted to the PDA through an inferior mini-sternotomy while the heart was beating. In both cases, the sternum was not cut transversely in order to prevent injury to the ITAs and pseudo-joint formation. With the use of this technique, exposure of the LAD and RCA was excellent. Postoperative recovery in both patients was uneventful and postoperative angiograms revealed widely patent grafts. This technique was very useful when performing off-pump CABG using bilateral ITAs.

Total syntheses of thiocoraline and BE-22179 and assessment of their DNA binding and biological properties

Full details of the total syntheses of thiocoraline (1) and BE-22179 (2), C(2) symmetric bicyclic octadepsipeptides possessing two pendant 3-hydroxyquinoline chromophores, are described in which their relative and absolute stereochemistry were established. Key elements of the approach include the late-stage introduction of the chromophore, symmetrical tetrapeptide coupling, macrocyclization of the 26-membered octadepsipeptide conducted at the single secondary amide site following disulfide formation, and a convergent assemblage of the tetradepsipeptide with introduction of the labile thiol ester linkage in the final coupling reaction under near racemization free conditions. By virtue of the late-stage introduction of the chromophore and despite the challenges this imposes on the synthesis, this approach provides ready access to a range of key chromophore analogues. Thiocoraline and BE-22179 were shown to bind to DNA by high-affinity bisintercalation analogous to echinomycin, but with little or no perceptible sequence selectivity. Both 1 and 2 were found to exhibit exceptional cytotoxic activity (IC(50) = 200 and 400 pM, respectively, L1210 cell line) comparable to echinomycin and one analogue, which bears the luzopeptin chromophore, was also found to be a potent cytotoxic agent.

Stability Characteristics of Dispersed Oil Droplets Prepared by the Microchannel Emulsification Method

A novel emulsification method, microchannel (MC) emulsification, was developed for making monodispersed regular-sized droplets in our laboratory. An oil-in-water dispersed system, in which phosphate buffer was used as the continuous phase, sodium dodecyl sulfate (SDS) as the surfactant, and clove oil as the dispersed phase, was prepared by this technique. The average diameter of oil droplets was about 20 µm, with a narrow size distribution. The stability characteristics of the dispersed oil droplets were investigated by an optical microscope and kinetic light scattering method. The stability of the dispersed oil droplets depended on the SDS concentration. When the SDS concentration was above the critical micelle concentration (CMC), the turbidity of the dispersed solution sharply increased at the initial stage. Optical microscopic observation has confirmed that a part of the oil droplets broke up with time, and submicrometer droplets appeared. On the other hand, when the SDS concentration was below the CMC, the turbidity of the dispersed solution had little change in the initial stage, showing that the oil droplets were very stable. The effect of ion concentration was also examined. The results showed that the stability of the oil droplets depended on the balance of the Van der Waals attraction and electrical repulsion between the oil droplets in low ion concentration. Copyright 2001 Academic Press.

Surgically treated aortic root aneurysm following aortic valve replacement

A 65-year-old man with aortic regurgitation underwent aortic valve replacement with a St. Jude Medical prosthetic valve about 6 years ago. At that time, the aortic root was slightly dilated at about 40 mm in diameter and the ascending aorta was within the normal range. This year, the man was diagnosed with an aortic root aneurysm in regular follow-up echocardiography. Chest-enhanced computed tomography and chest aortography at our hospital demonstrated a pear-like aortic root aneurysm about 60 mm in diameter. Elective operation for the aortic root aneurysm was conducted September 29, 1999, based on the Bentall procedure. Composite graft replacement with coronary reconstruction was conducted using a 28-mm Hemashield prosthetic graft and a 23-mm St. Jude Medical prosthetic valve under cardiopulmonary bypass. An 8-mm Hemashield graft was interposed on the left main coronary artery and the right coronary artery was directly anastomosed using a Carrel patch method. The postoperative course was uneventful and post-operative examination demonstrated good surgical results. Histological findings of the aortic aneurysm wall showed cystic medial necrosis. Surgical cases of aortic root aneurysm after aortic valve replacement are rare, but serious complications with the possibility of rupture or dissection warrant surgical intervention.

Synthesis of pyrimidine 2'-deoxy ribonucleosides branched at the 2'-position via radical atom-transfer cyclization reaction with a vinylsilyl group as a radical-acceptor tether

Recently, we developed a regio- and stereoselective method for introducing a vinyl group at the position beta to a hydroxyl group in halohydrins or alpha-phenylselenoalkanols via a radical atom-transfer cyclization reaction with a vinylsilyl group as a temporary connecting radical-acceptor tether. The synthesis of 2'-deoxy-2'-C-vinyl- and 2'-deoxy-2'-C-hydroxymethyluridines (7 and 8, respectively) and the corresponding 2'-deoxycytidine congeners (10 and 11, respectively), which were designed as potential antitumor and/or antiviral agents, was achieved using this radical atom-transfer cyclization as the key step. When the 2'-deoxy-2'-iodo-5'-O-monomethoxytrityl (MMTr) uridine derivative 19a, bearing a vinylsilyl group at the 3'-hydroxyl group, was heated with (Me(3)Sn)(2) and AIBN in benzene, the corresponding radical atom-transfer product was generated, which in turn was successively treated with tetrabutylammonium fluoride and TBSCl/imidazole to give the desired 2'-deoxy-5'-O-MMTr-3'-O-TBS-2'-C-vinyluridine (25). Compound 25 was successfully converted into the target 2'-deoxy-2'-branched pyrimidine ribonucleosides 7, 8, 10, and 11.

Analyses of spontaneous pink mutant events in the stamen hairs of Tradescantia clone BNL 4430 cultivated in a nutrient solution circulating growth chamber

In order to obtain more fundamental data on Tradescantia clone BNL 4430, one of the most suitable testers for environmental mutagens, the occurrences of spontaneous somatic pink mutations in the stamen hairs were scored for 52 weeks from 12 December 1998 to 10 December 1999, cultivating the young inflorescence-bearing shoots with roots in a nutrient solution circulating (NSC) growth chamber. The environmental conditions in the chamber were 22.0+/-0.5 degrees C during the 16h day with the light intensity of 7.5klx from white fluorescent tubes, and 20.0+/-0.5 degrees C at night. During the scoring period, 697,443 stamen hairs with an average cell number of 25.36 were observed and 2642 pink mutant events (PMEs) were detected. The overall spontaneous mutation frequency was 1.56+/-0.03 PMEs per 10(4) hair-cell divisions, and the frequency was significantly lower in May, July and August and significantly higher in November and December. By analyzing the sectoring patterns of 1856 PMEs (70.25% of PMEs detected), the most of 172 cases of multiple (two to five) pink sectors observed in the same hairs (scored as 232 PMEs for calculating mutation frequency) were found to be the results of events involving somatic recombinations occurred in single cells or cell lineages, rather than those of two or more independent somatic mutations occurred in different cells. This finding clearly shows the significance of somatic recombinations in producing such multiple sectors (382 sectors in total) which occupied 19.0% of the 2006 pink sectors in total analyzed. Somatic recombinations were considered to be playing a significant role also in producing single PMEs in the stamen hairs.

Metabolism of glycosylphosphatidylinositol-anchored proteins in Arabidopsis

Although glycosylphosphatidylinositol (GPI)-anchored proteins have now been found in several plants, very little is known regarding their metabolism there. This report describes studies of the biosynthesis and turnover of arabinogalactan proteins, a class of abundant GPI-anchored proteins secreted by cultured Arabidopsis cells.

Unlocking the allergenic structure of the major house dust mite allergen der f 2 by elimination of key intramolecular interactions

We report on the structural background of the remarkable reduction of allergenicity in engineering of the major house dust mite allergen Der f 2. Disruption of intramolecular disulfide bonds in Der f 2 caused extensive conformational change that was monitored by circular dichroism and gel-filtration analysis. The degree of conformational change correlated well with the degree of reductions in the capacity to bind IgE and to induce histamine release from basophils in mite-allergic patients. Loosening the rigid tertiary structure by elimination of key intramolecular interactions is an effective strategy to reduce the number of high affinity IgE epitopes of allergen vaccine.

Effects of proline mutations in the major house dust mite allergen Der f 2 on IgE-binding and histamine-releasing activity

Der f 2 is the major group 2 allergen from house dust mite Dermatophagoides farinae and is composed of 129 amino-acid residues. Wild-type and six proline mutants of Der f 2 (P26A, P34A, P66A, P79A, P95A, and P99A) expressed in Escherichia coli were refolded and purified. Formations of intramolecular disulfide bonds in the purified proteins were confirmed correct. The apparent molecular masses analyzed by gel-filtration were 14-15 kDa. The IgE-binding capacity in the sera of seven mite-allergic patients, inhibitory activity for IgE-binding to immobilized wild-type Der f 2, and activity to stimulate peripheral blood basophils to release histamine in two volunteers were analyzed. P95A and P99A, which slightly differed from the wild-type Der f 2 in their CD spectrum, showed reduced IgE-binding, reduced inhibitory activity, and less histamine-releasing activity than the wild-type. P34A also showed reduced allergenicity. Considering that Pro95, Pro99 and Pro34 are closely located in loops at one end of the tertiary structure of Der f 2, we concluded that these loop regions included an IgE-binding site common to all tested patients. P66A showed reduced IgE-binding in two sera out of seven. P26A and P79A showed no reduced allergenicity. However, in immunoblot analysis after SDS/PAGE under reduced conditions, P79A showed no or markedly reduced IgE-binding while the other mutants showed IgE-binding corresponding to that in the assay using correctly refolded proteins. This suggests that Pro79 is involved in refolding of Der f 2. The findings in this study are important for the understanding of the antigenic structure of mite group 2 allergens and for manipulation of the allergens for specific immunotherapy.

Twenty-two-year follow-up of saphenous vein grafts in pediatric Kawasaki disease

We describe 2 Kawasaki disease patients with excellent long-term patency of saphenous vein grafts, who underwent coronary artery bypass at age 7 and 9 years, respectively, and demonstrated normal growth during 22 years of follow-up. The grafts showed no deterioration and played an important role in coronary blood supply.

Tricuspid valve replacement after cardiac transplantation

Tricuspid regurgitation, a fairly common finding after cardiac transplantation, is generally mild or moderate, and is not clinically significant. The etiology of tricuspid regurgitation is not entirely understood, and experience with valve replacement after cardiac transplantation is limited. We describe a case of progressively severe tricuspid regurgitation ultimately requiring tricuspid valve replacement. At operation, the ruptured chordae of the posterior part of anterior and septal leaflet with resulting partially flail leaflets were found. Examination of the papillary muscle showed origins of several of the ruptured chordae. Damage to the tricuspid subvalvular apparatus at endomyocardial biopsy appeared to be a possible cause. A 31-mm Carpentier-Edwards porcine valve was implanted. This was because replacement with a mechanical prosthesis would prevent future right-side heart catheterization and endomyocardial biopsy and in valve repair, the patient remains exposed to the risk of the recurrence of chordal rupture. We discuss proposed causes and choices in surgical technique.

cDNA cloning of putative rat acetyl-CoA transporter and its expression pattern in brain

Rat acetyl-CoA transporter gene (Acatn) encodes a hydrophobic multi-transmembrane protein involved in the O-acetylation of gangliosides. O-acetylated gangliosides have been found to play important roles in the embryonic development of the nervous system. We have isolated rat Acatn cDNA by PCR cloning. The amino acid sequence of rat Acatn exhibited 92% and 96% homology with human and mouse sequences, respectively. The mRNA was expressed in brain at all developmental stages. Acatn expression was higher in embryonic and postnatal rats than in adult rats. Cellular localization of Acatn mRNA in adult rat brain was also analyzed by in situ hybridization. Acatn mRNA expression was detected in the neuronal cells of cerebellum, hippocampus, hypothalamus, cortex, olfactory bulb, and dorsal and ventral anterior olfactory nucleus in adult rat brain.

Continuous estimation of systolic blood pressure using the pulse arrival time and intermittent calibration

A continuous noninvasive method of systolic blood pressure estimation is described. Systolic blood pressure is estimated by combining two separately obtained components: a higher frequency component obtained by extracting a specific frequency band of pulse arrival time and a lower frequency component obtained from the intermittently acquired systolic blood pressure measurements with an auscultatory or oscillometric system. The pulse arrival time was determined by the time interval from QRS apex in electrocardiogram to the onset of photoplethysmogram in a fingertip beat-by-beat via an oximetric sensor. The method was examined in 20 patients during cardiovascular surgery. The estimated values of systolic blood pressure were compared with those measured invasively using a radial arterial catheter. The results showed that the correlation coefficients between estimated values and invasively obtained systolic blood pressure reached 0.97 +/- 0.02 (mean +/- SD), and the error remained within +/- 10% in 97.8% of the monitoring period. By using a system with automatic cuff inflation and deflation to acquire intermittent systolic blood pressure values, this method can be applicable for the continuous noninvasive monitoring of systolic blood pressure.

An interleukin-6-producing cardiac myxoma associated with mediastinal lymphadenopathy

We report our experience with a patient whose mediastinal lymphadenopathy resolved after resection of a cardiac myxoma that secreted interleukin-6 (IL-6). The patient was a 68-year-old female who complained of nocturnal chest discomfort related to congestive heart failure. An echocardiogram demonstrated a large left atrial mass. A computed tomogram showed not only the left atrial mass but multiple enlarged mediastinal lymph nodes. The serum IL-6 level was markedly elevated at 13.7 pg/ml. After resection of the cardiac myxoma, serum IL-6 returned to the normal range. A repeat computed tomogram showed no mediastinal lymphadenopathy. We believe that overproduction of IL-6 by the cardiac myxoma was the cause of the mediastinal lymphadenopathy.

The first synthesis of herbicidin B, a tricyclic-sugar adenine nucleoside antibiotic, using samarium diiodide-promoted aldol-type C-glycosidation reaction as a key-step

A first total synthesis of the nucleoside antibiotic herbicidin B (1) was achieved in which a novel aldol-type C-glycosidation reaction promoted by samarium diiodide (SmI2) was used as a key step. Construction of the desired stereochemistry of the tricyclic-sugar moiety was successfully achieved by conformational restriction strategy based on repulsion between adjacent bulky protecting groups on the pyranose ring.

Renovascular hypertension observed in a patient with antiphospholipid-antibody syndrome

The antiphospholipid-antibody syndrome is associated with an increased incidence of arterial and venous thrombosis. Although renal infarction has been observed in these patients, stenotic lesions of the renal artery associated with the antiphospholipid-antibody syndrome have not been reported. A 47-year-old male with a history of hypertension for 7 years developed blurred vision secondary to thrombotic occlusion of the central retinal artery. Laboratory and radiologic examinations revealed renal dysfunction, a positive anticardiolipin antibody, and narrowing of the right renal artery. Successful percutaneous transluminal renal artery angioplasty resulted in normalization of the blood pressure and recovery of renal function.

Regulation of UDP-glucose:ceramide glucosyltransferase-1 by ceramide

We report that the expression of mRNA and the activity of UDP-glucose:ceramide (Cer) glucosyltransferase-1 (GlcT-1) of human hepatoma Huh7 and mouse melanoma B16 cells increases after treatment with bacterial sphingomyelinase or upon addition of short-chain Cer. Interestingly, however, GlcT-1 gene transcription was not increased by Cer when GlcT-1 cDNA was introduced with the CMV promoter in GlcT-1-deficient GM95 cells, suggesting that the normal promoter region of GlcT-1 gene is essential for the response. The conversion of C6-Cer to C6-GlcCer occurred much more rapidly in GlcT-1-overexpressing Huh7 cells than in mock transfectants. As a result, GlcT-1-overexpressing cells acquired a greater resistance to C6-Cer-mediated cell death.

Genomic structure and promoter analysis of putative mouse acetyl-CoA transporter gene

The acetyl-CoA transporter gene (Acatn) encodes a hydrophobic, multitransmembrane protein that is involved in the process of O-acetylation of sialic acid residues on gangliosides. O-Acetylated gangliosides have been found to play important roles in tissue development and organization during early embryonic stages. We have cloned the gene for mouse acetyl-CoA transporter. The gene spans approximately 20 kb and is composed of seven exons and six introns. A single transcription initiation site, 371 bp upstream of the ATG start codon, was identified. The promoter region was found to lack a TATA box. However, several potential transcription factor binding motifs such as AP1, AP2, C/EBPalpha, C/EBPbeta, HSF, GATA2 and MZF1 were identified in the promoter region.