The lipid lowering effect of plant sterol ester capsules in hypercholesterolemic subjects

Background  

Foods enriched with phytosterols have been proven to be an effective therapy to improve blood lipid profiles. However, none of the studies have investigated the efficacy in lipid lowering of plant sterol esters (PSE) in capsule form. The objective of this study is to determine if the plant sterol esters (PSE) in capsule form (1.3 grams of PSE/day) lowered plasma cholesterol levels and lipid ratios in free-living hypercholesterolemic subjects during a 4-week intervention period.     

Customary use of plant sterol and plant stanol enriched margarine is associated with changes in serum plant sterol and stanol concentrations in humans

The consumption of products enriched with plant sterol or stanol esters lowers serum total and LDL-cholesterol concentrations, thereby most likely reducing the risk of coronary heart disease. However, using plant sterol (not plant stanol) enriched products elevates serum plant sterol concentrations in humans. This may be unwanted because health effects of elevated serum plant sterol concentrations are still controversial. Within postlaunch monitoring of functional foods, we compared serum plant sterol and plant stanol concentrations among users of plant sterol (n = 67) or plant stanol (n = 13) enriched margarines with those of matched nonusers (n = 81) in the ongoing Dutch Doetinchem cohort study. Subjects (aged 29-67 y) were examined in 1994-1998 (before the introduction of enriched margarines) and re-examined in 1999-2003. Serum concentrations of plant sterols and stanols were measured in samples from nonfasting subjects by GLC-MS. Intake of plant sterols was 1.1 +/- 0.6 g/d and was associated with a decrease of serum total cholesterol concentration of 0.25 +/- 0.91 mmol/L (4%, P < 0.05), a change that differed (P < 0.05) from the nonsignificant increase in nonusers (+2%, 0.12 +/- 0.78 mmol/L, P = 0.16). Cholesterol-standardized serum sitosterol and campesterol increased in plant sterol users by 22% (P < 0.0001) and 103% (P < 0.0001), respectively. Cholesterol-standardized serum sitostanol and campestanol increased in plant stanol users by 197% (P = 0.02) and 196% (P = 0.01). To our knowledge, these data are the first to show changes in serum cholesterol, plant sterol, and plant stanol concentrations after (long-term) consumption of plant sterol and stanol enriched margarines in a free-living population in a nonexperimental setting. Whether the increased serum sterol concentrations result in adverse side effects needs to be investigated in future postlaunch monitoring studies.     

Low and moderate-fat plant sterol fortified soymilk in modulation of plasma lipids and cholesterol kinetics in subjects with normal to high cholesterol concentrations: report on two randomized crossover studies

Background  

Although consumption of various plant sterol (PS)-enriched beverages is effective in lowering plasma cholesterol, the lipid-lowering potential of PS in a soymilk format has not been investigated thoroughly. Therefore, to evaluate the efficacy of PS-enriched soy beverages on plasma lipids and cholesterol kinetics, we conducted two separate 28 d dietary controlled cross-over studies. In study 1, the cholesterol-lowering efficacy of a low-fat (2 g/serving) PS enriched soy beverage was examined in 33 normal cholesterolemic subjects in comparison with 1% dairy milk. In study 2, we investigated the efficacy of a moderate-fat (3.5 g/serving) PS-enriched soy beverage on plasma cholesterol concentrations and cholesterol kinetic responses in 23 hypercholesterolemic subjects compared with 1% dairy milk. Both the low and moderate-fat PS-enriched soymilk varieties provided 1.95 g PS/d. Endpoint plasma variables were analyzed by repeated-measures ANOVA using baseline values as covariates for plasma lipid measurements.     

Plant stanol esters affect serum cholesterol concentrations of hypercholesterolemic men and women in a dose-dependent manner

The effect of plant stanol ester on serum cholesterol is dose-dependent. However, it is not clear what the dose is beyond which no additional benefit can be obtained. Therefore, we determined the dose-response relationship for serum cholesterol with different doses of plant stanol ester in hypercholesterolemic subjects. In a single-blind design each of 22 men or women consumed five different doses of plant stanol [target (actual) intake 0 (0), 0.8 (0.8), 1.6 (1.6), 2.4 (2.3), 3.2 (3.0) g/d] added as plant stanol esters to margarine for 4 wk. The order of dose periods was randomly determined. Serum total cholesterol concentration decreased (calculated in reference to control) by 2.8% (P = 0.384), 6.8% (P < 0.001), 10.3% (P < 0.001) and 11.3% (P < 0.001) by doses from 0.8 to 3.2 g. The respective decreases for LDL cholesterol were 1.7% (P = 0. 892), 5.6% (P < 0.05), 9.7% (P < 0.001) and 10.4% (P < 0.001). Although the decreases were numerically greater with 2.4 and 3.2 g doses than with the 1.6 g dose, these differences were not significant (P = 0.054-0.516). Serum plant stanols rose slightly, but significantly with the dose (P < 0.001). Apolipoprotein B concentration was decreased significantly already at the dose of 0.8 g (8.7%, P < 0.001). Apolipoprotein E genotype did not affect the lipid responses. We conclude that significant reduction of serum total and LDL cholesterol concentrations is reached with the 1.6-g stanol dose, and increasing the dose from 2.4 to 3.2 g does not provide clinically important additional effect.     

Fish-oil esters of plant sterols differ from vegetable-oil sterol esters in triglycerides lowering,carotenoid bioavailability and impact on plasminogen activator inhibitor-1 (PAI-1) concentrations in hypercholesterolemic subjects

Background  

Consumption of plant sterol (PS) esters lower low-density lipoprotein (LDL)-cholesterol levels by suppressing intestinal absorption of cholesterol. Commercially available PS are mainly esterified to omega-6 fatty acid (FA), such as sunflower oil (SO) FA. Emerging trends include using other sources such as olive oil (OO) or omega-3 FA from fish oil (FO), known to exert potent hypotriglyceridemic effects. Our objective was to compare the actions of different FA esterified to PS on blood lipids, carotenoid bioavailability as well as inflammatory and coagulation markers.     

Dietary plant sterols supplementation does not alter lipoprotein kinetics in men with the metabolic syndrome

Dietary plant sterols supplementation has been demonstrated in some studies to lower plasma total and LDL cholesterol in hypercholesterolemic subjects. The cholesterol lowering action of plant sterols remains to be investigated in subjects with the metabolic syndrome. In a randomized, crossover study of 2 x 4 week therapeutic periods with oral supplementation of plant sterols (2 g/day) or placebo, and two weeks placebo wash-out between therapeutic periods, we investigated the effects of dietary plant sterols on lipoprotein metabolism in nine men with the metabolic syndrome. Lipoprotein kinetics were measured using [D3]-leucine, gas chromatography-mass spectrometry and compartmental modeling. In men with the metabolic syndrome, dietary plant sterols did not have a significant effect on plasma concentrations of total cholesterol, triglycerides, LDL cholesterol, HDL cholesterol, apolipoprotein (apo) B, apoA-I or apoA-II. There were no significant changes to VLDL-, IDL-, LDL-apoB or apoA-I fractional catabolic rates and production rates between therapeutic phases. Relative to placebo, plasma campesterol, a marker of cholesterol absorption was significantly increased (2.53 +/- 0.35 vs. 4.64 +/- 0.59 mug/ml, p < 0.05), but there was no change in plasma lathosterol, a marker of endogenous cholesterol synthesis. In conclusion, supplementation with plant sterols did not appreciably influence plasma lipid or lipoprotein metabolism in men with the metabolic syndrome. Future studies with larger sample size, stratification to low and high cholesterol absorbers and cholesterol balance studies are warranted.     

Comparison of the effects of plant sterol ester and plant stanol ester-enriched margarines in lowering serum cholesterol concentrations in hypercholesterolaemic subjects on a low-fat diet

OBJECTIVE: To investigate cholesterol-lowering effects of stanol ester (STAEST) and sterol ester (STEEST)-enriched margarines as part of a low-fat diet. DESIGN: According to a Latin square model randomized double-blind repeated measures design with three test margarines and three periods. SETTING: Outpatient clinical trial with free-living subjects. SUBJECTS: Thirty-four hypercholesterolaemic subjects completed the study. Interventions: Subjects consumed three rapeseed oil-based test margarines (STAEST, STEEST and control (no added stanols or sterols)) as part of a low-fat diet each for 4 weeks. RESULTS: Mean daily intake of total plant sterols plus stanols was 2.01-2.04 g during the two test margarine periods. In reference to control, serum total cholesterol was reduced by 9.2 and 7.3% with the STAEST and STEEST margarine, respectively (P<0.001 for both). The respective reductions for low-density lipoprotein (LDL) cholesterol were 12.7 and 10.4% (P<0. 001). The cholesterol-lowering effects of the test margarines did not differ significantly. The presence of apolipoprotein E4 allele had a significant effect on LDL cholesterol response during the STAEST margarine only. Serum sitosterol and campesterol increased by 0.83 and 2.77 mg/l with the STEEST (P<0.001), respectively and decreased by 1.18 and 2.60 mg/l with the STAEST margarine (P<0.001). Increases of serum sitostanol and campestanol were 0.11 and 0.19 mg/l with the STAEST margarine (P<0.001), repsectively. No significant changes were found in serum fat-soluble vitamin and carotenoid concentrations when related to serum total cholesterol. CONCLUSIONS: STAEST and STEEST margarines reduced significantly and equally serum total and LDL cholesterol concentrations as part of a low-fat diet. SPONSORSHIP: Grant to the University of Kuopio by Raisio Benecol Ltd, Raisio, Finland.     

Effects of fats high in stearic acid on lipid and lipoprotein concentrations in men.

The effects of beef tallow and cocoa butter, two fats with a high stearic acid content (C18:0), on serum lipid and lipoprotein concentrations were compared with the effects of butter fat and olive oil in 10 middle-aged men. Liquid-formula diets containing 40% of the calories from the test fat were fed in random order for 3 wk each, with lipoprotein concentrations measured on the last five days. Butter fat raised low-density lipoprotein (LDL) concentrations the most (4.23 +/- .15 mmol/L; mean +/- SE). Beef-tallow feeding resulted in significantly lower concentrations of LDL (4.03 +/- 0.18 mmol/L); cocoa butter resulted in even lower concentrations (3.82 +/- .15 mmol/L). The lowest concentration of LDL was observed with olive oil (3.62 +/- 0.18 mmol/L). Fecal excretion of fatty acids, after adjustment for fecal flow, indicated that oleic acid (C18:1) was 99% absorbed, palmitic acid (C16:0) was 96-97% absorbed, and stearic acid was 90-94% absorbed for the three fats containing significant amounts of stearic acid.     

Cholesterol-lowering effect of spreads enriched with microcrystalline plant sterols in hypercholesterolemic subjects

Summary Background Plant sterols have been shown to reduce serum lipid concentrations. The effectiveness is highly dependent on the physical state of the plant sterols. By means of a new crystallizing method, plant sterols can be added into dietary fats and oils homogeneously. In this fat ingredient, plant sterols are in a microcrystalline form. Aims of the study We investigated the cholesterol-lowering effect and possible side effects of vegetable oil-based spreads fortified with two different doses of microcrystalline plant sterols. Methods: This double-blind randomized, placebo-controlled study consisted of a 6-wk run-in and a 6-month experimental period. During the run-in period, all 155 hypercholesterolemic subjects received rapeseed oil-based control spread. In the beginning of the experimental period subjects were randomly assigned into one of three experimental groups. The control group continued to use control spread, and the two test groups used spreads with added plant sterols of either 1.5 g/d or 3.0 g/d. The subjects consumed test spreads as a part of their normal diet without any restrictions in lifestyle and diet. Results Plasma total- and LDL-cholesterol concentrations were significantly reduced by 7.5–11.6 % (0.46–0.62 mmol/l) in groups consuming margarine enriched with free plant sterols, compared with the control group. The effects were similar between the two groups consuming either 1.5 g or 3.0 g plant sterols per day. No effect on HDL-cholesterol or triacylglycerol concentrations occurred. The test spreads did not induce any adverse effects in blood clinical chemistry, hematology or decreases in serum concentrations of lipid soluble vitamins. Conclusions Microcrystalline plant sterols are effective in lowering serum total- and LDL-cholesterol concentrations without obvious side effects. The daily dose of 1.5 g plant sterols is enough to reach the maximum effect. Received: 5 December 2000 / Accepted: 14 March 2001     

Changes in basal and postmethionine load concentrations of total homocysteine and cystathionine after B vitamin intervention

BACKGROUND: Vitamin B-6 is necessary for the metabolism of homocysteine and is often used in combination with folic acid and vitamin B-12 in clinical trials that investigate whether the lowering of plasma total homocysteine (tHcy) can prevent vascular disease. OBJECTIVE: We compared the effects of vitamin B-6 with the effects of folic acid and vitamin B-12, as used in the Western Norway B-vitamin Intervention Trial (WENBIT), on basal and postmethionine load (PML) tHcy and cystathionine concentrations. DESIGN: Ninety patients with suspected coronary artery disease were randomly assigned to 1 of 4 groups to receive daily oral treatment with 1) 0.8 mg folic acid, 0.4 mg vitamin B-12, and 40 mg vitamin B-6 (group A); 2) 0.8 mg folic acid and 0.4 mg vitamin B-12 (group B); 3) 40 mg vitamin B-6 (group C); or 4) placebo (group D). For the first 2 wk, groups A and B received additional folic acid (5 mg/d). A methionine-loading test was performed at baseline and after 3 mo. RESULTS: Treatment with folic acid and vitamin B-12 caused a rapid and significant lowering of basal (31%) and PML tHcy concentrations (22%), with no effect on cystathionine. Vitamin B-6 did not change basal tHcy and had a significant but limited effect on PML tHcy concentrations. However, vitamin B-6 treatment markedly lowered basal and PML cystathionine by 31% and 42%, respectively. CONCLUSION: The folic acid and vitamin B-12 combination applied in WENBIT provides rapid, substantial, and long-term tHcy-lowering effects, whereas the effect of vitamin B-6 on tHcy was relatively small and confined to PML tHcy. However, vitamin B-6 treatment caused a marked reduction in plasma cystathionine. Cystathionine could be a useful marker for assessment of the vitamin B-6 effect and should, together with tHcy, be related to clinical outcome in ongoing trials.     

Effect of low zinc intakes on basal metabolic rate, thyroid hormones and protein utilization in adult men

Basal metabolic rate (BMR), thyroid hormones and protein utilization were measured in six young men participating in a 75-d metabolic study of low zinc intakes. During metabolic period (MP) 1 (12 d) and MP 3 (9 d) the subjects received 16.5 mg Zn/d. During MP 2 (54 d) they received 5.5 mg Zn/d. Nitrogen intake averaged 12.6 g/d. Mean BMR significantly decreased from 1.00 +/- 0.06 to 0.91 +/- 0.05 kcal/(kg X h) (mean +/- SD) with the low zinc diet and tended to increase during period 3. Serum thyroid-stimulating hormone, thyroxine (T4) and free T4 tended to decrease during the low zinc period and to increase when the adequate zinc diet was fed; only the decrease in free T4 was significant at P less than 0.05, however. Among the measures of protein status, urinary urea excretion, serum prealbumin, albumin and retinol-binding protein levels all decreased significantly during the low zinc period. The results suggest that low zinc intakes may be associated with decreases in BMR. In addition, decreases in thyroid hormone levels and alterations in protein utilization may occur.     

Effect of buttermilk consumption on blood pressure in moderately hypercholesterolemic men and women

ObjectivesMilk fat globule membrane (MFGM) found in buttermilk is rich in unique bioactive proteins. Several studies suggest that MFGM proteins possess biological activities such as cholesterol-lowering, antiviral, antibacterial, and anticancer properties, but data in humans are lacking. Furthermore, to our knowledge, no study has yet investigated the antihypertensive potential of MFGM proteins from buttermilk. The aim of this study was to investigate the effects of buttermilk consumption on blood pressure and on markers of the renin–angiotensin–aldosterone (RAS) system in humans.MethodsMen and women (N = 34) with plasma low-density lipoprotein cholesterol < 5 mmol/L and normal blood pressure (< 140 mm Hg) were recruited in this randomized, double-blind, placebo-controlled, crossover study. Their diets were supplemented with 45 g/d of buttermilk and with 45 g/d of a macro-/micronutrient-matched placebo in random order (4 wk for each diet).ResultsButtermilk consumption significantly reduced systolic blood pressure (−2.6 mm Hg; P = 0.009), mean arterial blood pressure (−1.7 mm Hg; P = 0.015), and plasma levels of the angiotensin I-converting enzyme (−10.9%; P = 0.003) compared with the placebo, but had no effect on plasma concentrations of angiotensin II and aldosterone.ConclusionShort-term buttermilk consumption reduces blood pressure in normotensive individuals.     

芜湖市男男性行为者焦虑状况及干预效果调查

目的通过了解芜湖市男男性行为者（MSM）焦虑状况及其影响因素,为制定科学的干预措施提供依据。方法采用焦虑自评量表,结合哨点监测对MSM进行匿名问卷调查以及开展健康教育、解除心理疑虑、提供心理支持等。结果162名MSM完成干预前调查,其中75人完成干预后调查。经logistic回归分析发现,样本来源场所档次越低,焦虑程度越高。干预措施对轻度焦虑患者有效,对74．1％的中度焦虑患者有效,对重度焦虑患者效果较差。结论应把多种措施结合起来开展干预工作,以减轻患者的心理负担。     

Effects of hazelnut-enriched diet on plasma cholesterol and lipoprotein profiles in hypercholesterolemic adult men

OBJECTIVE: Frequent consumption of nuts is associated with favorable plasma lipid profiles and reduced risk of coronary heart disease (CHD). This study was conducted to investigate the effects of hazelnut-enriched diet on plasma cholesterol and lipoprotein profiles in hypercholesterolemic adult men compared with baseline and control diet, and also to measure the anthropometric parameters, habitual physical activities, nutrient intake and endothelial function. SUBJECTS AND DESIGN: Fifteen hypercholesterolemic men aged 48+/-8 years were recruited voluntarily. A well-controlled, 2-period (P1 and P2) study design with a total of 8-week was implemented. In the P1, subjects consumed a control diet (low-fat, low-cholesterol and high-carbohydrate). During the P2, the control diet was supplemented with MUFA-rich hazelnut (40 g/day), which provided 11.6% of total energy content. Anthropometric parameters and habitual physical activities were recorded. Plasma total and HDL cholesterol, TAG, ApoA-1, Apo B, total homocysteine and glucose concentrations were measured. All parameters and measurements were obtained at baseline and end of each 4-week diet period. RESULTS: Body weights of subjects remained stable throughout the study. Compared with baseline, the hazelnut-enriched diet decreased (P<0.05) the concentrations of VLDL cholesterol, triacylglycerol, apolipoprotein B by 29.5, 31.8, and 9.2%, respectively, while increasing HDL cholesterol concentrations by 12.6%. Total/HDL cholesterol and LDL/HDL cholesterol ratios favorably decreased (P<0.05). Although insignificant there was a decreasing trend for the rest of parameters, particularly in total (5.2%) and LDL cholesterol (3.3%) in subjects consuming a hazelnut-enriched diet compared to that of the baseline. No changes were found in fasting levels of glucose, Apo A-1 and homocysteine between the control and hazelnut-enriched diets. CONCLUSIONS: This study demonstrated that a high-fat and high-MUFA-rich hazelnut diet was superior to a low-fat control diet because of favorable changes in plasma lipid profiles of hypercholesterolemic adult men and, thereby positively affecting the CHD risk profile. SPONSORSHIP: Funding provided by a grant from the Hazelnut Promotion Group, Giresun, Turkey.     

Acute effects of vibration on digital circulatory function in healthy men.

OBJECTIVES--To investigate the local and central pathophysiological mechanisms involved in the acute effects of unilateral vibration on the digital circulation of healthy men. METHODS--Finger blood flow (FBF) and finger skin temperature (FST) in thermoneutral conditions, and the percentage change in finger systolic pressure (FSP%) after local cooling from 30 to 10 degrees C were measured in the fingers of both hands in eight men (aged 23-47 years) who were not occupationally exposed to hand transmitted vibration. The right hand was exposed for 30 minutes to sinusoidal vibration with a frequency of 125 Hz and an acceleration of 87.5 m.s-2 rms (root mean square). A control condition consisted of exposure to static load only (10 N) without vibration. The measures of digital circulation were taken before exposure to vibration and static load and at 0, 30, 60, and 90 minutes after the end of each exposure. RESULTS--Exposure to static load caused no significant changes in FBF, FST, or FSP% in either the test right or the control left finger. Immediately after vibration exposure, there was a temporary increase in FBF in the vibrated right finger, whereas the non-vibrated left finger showed no vasodilation. In both the vibrated and non-vibrated fingers, FBF and FST were significantly reduced during the recovery time. A large variability between subjects was found for FBF and, to a lesser extent, for FST. In the vibrated right hand the decrease in FBF was significantly related to cold induced vaso-constriction in the digital vessels. Such a relation was not found in the non-vibrated left hand. CONCLUSIONS--The results of this investigation suggest that acute vibration can disturb the function of digital vessels through two different and opposite mechanisms. Vibration seems to produce local vasodilation and to trigger a central sympathetic reflex vasoconstriction that can be recorded in the ipsilateral and the contralateral finger to vibration. Both local and central vasoconstrictor mechanisms are likely to be involved in the responsiveness to cold found in the digital vessels of a vibrated finger.     

The effects of low cholesterol, high polyunsaturated fat, and low fat diets on plasma lipid and lipoprotein cholesterol levels in normal and hypercholesterolemic subjects

The effects of various cholesterol-lowering diets on plasma lipid and lipoprotein cholesterol levels were assessed in normal and hypercholesterolemic subjects. The base-line diet was an ad libitum hospital diet of normal composition. Diet A was a 20% protein, 40% carbohydrate, 40% fat, polyunsaturated:saturated fat ratio 0.1 to 0.3, 250 to 300 mg cholesterol diet, diet B was identical to diet A except that the polyunsaturated/saturated fat ratio was 1.8 to 2.2, and diet C was a 20% protein, 80% carbohydrate, very low fat (5 to 10 g), polyunsaturated/saturated fat ratio 0.1 to 0.3, 150 to 200 mg cholesterol diet. Diet A (low cholesterol) caused mean reductions in plasma, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol of 5.9, 5.6, and 6.3%, respectively, in 11 normal subjects. Diet B (low cholesterol, high polyunsaturated fat) caused significant decreases in plasma cholesterol, LDL cholesterol and HDL cholesterol of 17.0, 16.2, and 17.4%, respectively, in 12 normal subjects; and reductions of 11.0, 10.8, and 17.1%, respectively, in 19 hypercholesterolemic subjects. Diet C (low cholesterol, very low fat) produced significant mean decreases in plasma, LDL, and HDL cholesterol of 26.7, 29.9, and 27.9%, respectively, in 11 normal subjects, and in nine hypercholesterolemic patients of 22.6, 27.2, and 28.6%, respectively. The reductions in plasma cholesterol caused by these diets were therefore due to decreases in both LDL and HDL cholesterol with no significant changes in the LDL cholesterol:HDL cholesterol ratio.     

对男男性行为者以防治性病为主预防艾滋病综合干预效果评价

目的评价以防治性病为主的同伴综合干预对男男性行为人群（men who have sex with men,MSM）在改变高危行为、接受健康服务及控制性病和HIV感染方面的效果。方法通过滚雪球法招募在常州市主要公共活动场所和互联网等的MSM人群。采用现场流行病学现场干预实验方法,在基线调查基础上,在MSM人群中开展以定点性病门诊提供免费或低廉的性病诊疗服务为主要形式的同伴综合干预。一年半后进行干预效果评估。问卷调查内容主要包括对象的一般人口学资料、行为状况和接受干预服务状况,同时采集血液和尿样样本以检测HIV、梅毒、淋球菌和生殖道沙眼衣原体。用SPSS13．0软件进行Х^2检验、t检验和Fisher’s确切检验,均以P〈0．05为差异有统计学意义。结果经过一年半的项目实施后,干预后与干预前相比,调查对象接受健康服务以及性病诊疗均有显著性提高（P〈0．01）。最近6个月有过肛交行为者由63．90％下降至51．15％（P〈0．01）,有过性交易者由13．16％下降至7．76％（P〈0．05）;最近一次男性肛交使用安全套者由80．67％下降至72．47％（P〈0．05）。近半年性虐待由6．65％下降至1．81％（P〈0．05）。HIV和梅毒（ELISA阳性）感染率干预前后差异无统计学意义,但现症梅毒（TRUST阳性）、淋球菌和生殖道沙眼衣原体感染则显著性下降（P〈0．05）。结论依托免费定点性病门诊开展以防治性病为主的同伴综合干预模式,可促进MSM人群降低高危性行为并主动进行性病和HIV的检测咨询与治疗,有效地控制HIV和梅毒感染。