Hemodynamic response of ovarian artery after hCG injection

We have analyzed ovarian hemodynamics immediately after human chorionic gonadotropin (hCG) administration in patients treated by clomiphene-hCG and human menopausal gonadotropin-hCG. This study involved 40 infertile women who signed consents to participate in this study. After intramuscular injection of 10000 IU hCG, the change of ovarian arterial blood flow (BF) was evaluated by color Doppler. Pulsatility index, resistance index, maximum velocity (V(max)), mean velocity, minimum velocity, cross-sectional area of ovarian artery (Area) and BF were measured before and 15-180 min after hCG administration. In the 36 subjects in which ovulation was induced successfully, V(max) and BF increased significantly even at 15 min after hCG administration and thereafter. In the 4 non-ovulatory subjects, no significant changes in any of indices at any of measured time points were observed. Comparative study of non-ovulatory and ovulatory subjects suggested that ovulation may be predicted by the ovarian hemodynamic analysis immediately after hCG administration.

Comparison of Doppler ultrasonography and the hepatic venous pressure gradient in assessing portal hypertension in liver cirrhosis

BACKGROUND AND AIM

This prospective study aimed to determine whether Doppler ultrasonography can represent the hepatic venous pressure gradient (HVPG) as an assessment of the severity of portal hypertension and the response to terlipressin, which reduces the portal pressure in liver cirrhosis.

METHODS

The HVPG and the Doppler ultrasonographic parameters, such as the portal venous velocity and the splenic venous velocity, the pulsatility and the resistive index of the hepatic, splenic and renal arteries were measured in 138 patients with liver cirrhosis. The changes in the HVPG and the portal venous velocity after administering terlipressin were evaluated in 43 of the 138 patients. The patients who showed a reduction in the HVPG of more than 20% of the baseline were defined as responders to terlipressin.

RESULTS

None of the Doppler ultrasonographic parameters correlated with the HVPG. Both the HVPG (28.0 +/- 19.8%) and the portal venous velocity (29.7 +/- 13.2%) showed a significant reduction after terlipressin administration. However, the portal venous velocity decreased significantly, not only in the responders (31.0 +/- 12.0%) but also in the non-responders (25.2 +/- 16.4%).

CONCLUSIONS

Doppler ultrasonography does not represent the HVPG, and is therefore not suitable for replacing HVPG as a means of assessing the severity of portal hypertension and the response to drugs which reduce the portal pressure in liver cirrhosis.

Effects of adult growth hormone deficiency and growth hormone replacement on circadian rhythmicity

In health, growth hormone (GH) is secreted in a circadian rhythm with superimposed pulsatility. Temporal fluctuations of hormone concentrations are essential for physiological action, and loss of diurnal rhythm is important in the development of disease. GH feedback occurs through the hypothalamus and involves neuropeptides such as somatostatin, GH-releasing hormone, GH-releasing peptides and neuropeptide Y. In addition, the same neuropeptides are involved in the regulation of other hormone axes and biological systems, thus, establishing a link through which regulation by GH may occur. Clinical features of adult growth hormone deficiency (AGHD) include abnormal body composition, reduction in quality of life, osteoporosis and increased risk of cardiovascular mortality. In health, many of the factors which regulate these features demonstrate circadian rhythmicity and pulsatility. Furthermore, AGHD is associated with abnormalities in the periodic variation of such controlling factors. GH replacement therapy, administered in the form of timed, intermittent subcutaneous injections, results in improvement of many of the clinical effects of AGHD, and is associated with normalization of the temporal fluctuations. Currently, there remains scope for further investigation of the effects of AGHD and subsequent GHR on the circadian rhythmicity of many hormones and systems; and additional studies are required to understand the physiological significance of the changes observed to date.

Misoprostol and dinoprostone therapy for labor induction: a Doppler comparison of uterine and fetal hemodynamic effects

OBJECTIVE

To compare the effect of misoprostol (PGE(1)) versus dinoprostone (PGE(2)) on blood flow in uteroplacental circulation during labor induction.

STUDY DESIGN

Eighty-four women with indications for induction of labor were assigned to receive either misoprostol 50 microg per vagina every 4 h as needed or 0.5 mg doses of dinoprostone given intra-cervically every 6 h by means of a randomization table generated by computer. Doppler velocimetry of umbilical, uterine and arcuate arteries was performed immediately before and 2-3 h after the administration of misoprostol or dinoprostone. The SAS system was used to perform statistical analysis.

RESULTS

There were no significant changes of pulsatility index (PI), resistance index (RI) and systolic/diastolic (S/D) ratio in umbilical arteries after both prostaglandin compounds. Vaginal application of misoprostol significantly increased all ratios in arcuate artery and S/D ratio in uterine artery. Intra-cervically dinoprostone significantly increased PI, RI and S/D ratio in arcuate and uterine arteries.

CONCLUSIONS

Our results indicate that vaginal misoprostol and cervical dinoprostone administration increases uteroplacental resistance but does not affect umbilical blood flow. Misoprostol would be as safe and effective agent as dinoprostone for cervical ripening and labor induction.

Influence of drugs and gender on the arterial pulse wave and natriuretic peptide secretion in untreated patients with essential hypertension

Recent studies have suggested a differential influence of mean pressure and pulse pressure on myocardial infarction and stroke, and differences among the major drugs in their efficacy at preventing these individual endpoints. We hypothesized that antihypertensive drugs have differing influences upon the pulse wave even when their effects on blood pressure are the same. We studied 30 untreated hypertensive patients, aged 28-55 years, who were rotated through six 6-week periods of daily treatment with amlodipine 5 mg, doxazosin 4 mg, lisinopril 10 mg, bisoprolol 5 mg, bendrofluazide 2.5 mg or placebo. The best drug was repeated at the end of the rotation. Blood pressure readings and radial pulse tonometry (by Sphygmocor) were performed at each visit, and blood was taken for measurement of levels of atrial natriuretic peptide and brain natriuretic peptide (BNP). The Sphygmocor derivation of the central aortic pulse wave was used to measure time for transmission of the reflected wave (T(R)) and the augmentation index (AI), which is the proportional increase in systolic pressure due to the reflected wave. There was a dissociation between the effects of the drugs on blood pressure and pulse wave analysis. Bisoprolol caused the greatest falls in blood pressure and T(R), but was the only drug to increase AI. This paradoxical response to bisoprolol was associated with a 3-fold increase in plasma BNP levels. There was a smaller elevation of BNP in women compared with men, as described previously, and this elevation also was associated with significantly higher values of AI. Other drugs reduced AI, and this was associated with a significant decrease in BNP by amlodipine. In conclusion, antihypertensive drugs differ in their short-term effects on augmentation of the systolic pulse wave and secretion of BNP from the heart, regarded as a sensitive measure of strain on cardiomyocytes. These differences may help to explain cause-specific differences in outcome in recent trials.

Effect of latanoprost 0.005% and brimonidine tartrate 0.2% on pulsatile ocular blood flow in normal tension glaucoma

AIM

To determine the effect of brimonidine tartrate 0.2% and latanoprost 0.005% on pulsatile ocular blood flow (POBF) in patients with normal tension glaucoma (NTG).

METHOD

NTG patients with progressive optic neuropathy, new disc haemorrhage, or field defects that threatened fixation were enrolled into a randomised, investigator masked, crossover study. Group I patients received 4 weeks each of latanoprost, lubricant, and brimonidine, while group II patients received 4 weeks each of brimonidine, lubricant, and latanoprost. Diurnal POBF was measured at baseline and after each 4 week treatment.

RESULTS

25 patients completed the study and had reliable POBF measurement at each visit. There was no significant diurnal change in baseline POBF (p = 0.768). Latanoprost increased POBF by 213 (SD 257) micro l/min (22.8%, p <0.001) while brimonidine increased it by 97 (183) micro l/min (10.4%, p = 0.014). POBF increased at 8 am (p = 0.004), 12 noon (p = 0.002), and 4 pm (p <0.001) with latanoprost, while it increased only at 8 am (p = 0.016) with brimonidine. After adjusting for the factor of IOP, neither latanoprost nor brimonidine increased POBF significantly.

CONCLUSIONS

Latanoprost increases the mean POBF that is related to its IOP lowering effect. The increase in POBF noted after brimonidine is within the range of long term variation and may not be attributable to the drug effect.

Comparative effects of latanoprost (Xalatan) and unoprostone (Rescula) in patients with open-angle glaucoma and suspected glaucoma

PURPOSE

To compare, in paired eyes of open-angle glaucoma patients and glaucoma suspects, hydrodynamic and visual changes after 1 month of topical latanoprost in one eye and unoprostone in the other.

DESIGN

Single-center, institutional randomized clinical trial.

METHODS

After completing a washout period off all topical medication, 25 adults (mean age 54 +/- SEM 2 years) with bilateral open-angle glaucoma or glaucoma suspect status underwent morning (8 to 10 AM) and afternoon (1 to 3 PM) measurements of intraocular pressure (IOP), pulsatile ocular blood flow (POBF), contrast, sensitivity, frequency doubling technology, and Humphrey 10-2 perimetry (HVFA II) in both eyes. Each then started unoprostone 0.15% (Rescula) in one randomly assigned eye and latanoprost 0.005% (Xalatan) in the other. Unoprostone was administered at 8 AM and 8 PM and latanoprost at 8 PM with placebo at 8 AM, both from masked bottles. After 28 days, differences were determined for each measured variable by two-tailed paired t test.

RESULTS

Starting from similar baseline IOP levels, after 1 month of treatment, the mean morning IOP values differed according to the topical agent received (16.2 +/- SEM 0.6 mm Hg for latanoprost vs 17.9 +/- 0.7 mm Hg for unoprostone; P =.001). These morning pressures were 2.6 mm Hg lower than baseline in the eyes receiving latanoprost (P <.0001), and 1.6 mm Hg lower in unoprostone-treated eyes (P =.02). Afternoon values were 3.1 +/- SEM 0.6 lower than corresponding baseline in eyes receiving latanoprost, and 2.4 +/- SEM 0.6 mm Hg in unoprostone-treated eyes (P <.0001 from baseline for both medications; interdrug mean IOP difference; P =.04). Eyes receiving unoprostone showed a 1.7-db improvement in frequency doubling mean deviation (P =.03), the only significant visual function change observed. Pulsatile ocular blood flow increased 30% relative to baseline in eyes receiving latanoprost, (P <.0001) and 16% in eyes receiving unoprostone (P =.05) by the morning of day 28. That afternoon, mean POBF had increased 30% (P <.0001) relative to afternoon baseline values among eyes receiving latanoprost and 18% (P =.03) among those receiving unoprostone (interdrug change difference, P =.05). Humphrey perimetry and contrast sensitivity remained stable with both prostanoids.

CONCLUSIONS

Both latanoprost and unoprostone produced significant reductions in IOP and increases in POBF, with stable central and perimacular visual function. Latanoprost once daily produced IOP reduction and POBF increases nearly twofold greater than those obtained with unoprostone twice daily. These differences in IOP and POBF change between unoprostone and latanoprost were statistically significant.

Flow resistance in carotid and middle cerebral arteries in postmenopausal women: a comparative study of tibolone and continuous combined hormone replacement therapy

OBJECTIVE

The study sought to compare the vascular resistance and serum lipids of postmenopausal women assigned to tibolone therapy or continuous combined hormone replacement therapy.

DESIGN

This was a 6-month, prospective, single-blind, single-center, randomized study. A total of 50 healthy postmenopausal women were enrolled. At study end, 40 women had completed a 6-month follow-up. The first group (23 subjects) received conjugated equine estrogens (CEE) 0.625 mg/day and medroxyprogesterone acetate (MPA) 5 mg/day. The second group (17 subjects) received tibolone 2.5 mg/day. The pulsatility and resistance indexes of the carotid and middle cerebral arteries, and serum lipid profiles were monitored.

RESULTS

Comparisons demonstrated that there were no significant differences between the groups in terms of changes in the pulsatility index (PI) and the resistance index (RI) of the common carotid artery (CCA), internal carotid artery (ICA), and middle cerebral artery (MCA) within the study period. Both treatments effectively reduced the total cholesterol level and with no significant differences found between the two regimens. However, in comparing the two groups, we found that high-density lipoprotein (HDL) cholesterol levels were significantly lower in the tibolone group at either 3 months or 6 months after treatment, whereas a significantly higher triglycerides level was observed in the CEE + MPA group after 3 months of treatment. Low-density lipoprotein (LDL) cholesterol levels indicated no significant differences between the two groups after treatment.

CONCLUSIONS

The study demonstrated that major neck and cerebral vascular impedance was not influenced significantly by either regimen. Nonetheless, lipid profiles were affected differently by tibolone and by continuous combined CEE + MPA. However, whether or not these findings might modify cardiovascular risk is still unknown.

Early vascular abnormalities and de novo nitrate tolerance in diabetes mellitus

OBJECTIVE

The haemodynamic consequence of altered mechanical wall properties in diabetes can impair the compliance characteristics or pulsatile function of arteries before changes in calibre or peripheral resistance become evident. We studied the sensitivity of pulsatile and steady-state haemodynamic variables in identifying vascular abnormalities and assessing arterial responsiveness to glyceryl trinitrate (GTN) in patients with diabetes, free from clinical complications of the disease.

METHODS

Radial artery pressure waveforms were recorded in 22 patients with diabetes and 22 age- and sex-matched control subjects, using a calibrated tonometer device. A computer-based assessment of the diastolic pressure decay was used to quantify changes in arterial waveform morphology in terms of pulsatile (arterial compliance) and steady-state (peripheral resistance) haemodynamics. Pressure pulse waveforms were recorded before and 3, 6 and 9 min after the administration of 300 micro g of GTN.

RESULTS

Of the pulsatile and steady-state impedance parameters, only small artery compliance was significantly different in patients, 4.7 ml/mmHg (95% CI 3.8-5.8), compared with control subjects 7.1 ml/mmHg (95% CI 5.4-8.7); (p < 0.05). In response to GTN small artery compliance increased, and systemic vascular resistance decreased significantly in control subjects; (p < 0.05) but remained unchanged in patients with diabetes.

CONCLUSIONS

Arterial waveform analysis proved more sensitive in detecting early vascular abnormalities and tracking the haemodynamic effects of GTN in patients with diabetes than changes in total peripheral resistance. The diminished responsiveness of the arterial vasculature to organic nitrates may have therapeutic implications for the treatment of cardiovascular disease in diabetes mellitus.

Influence of isoflurane anesthesia on pulsatility index and peak systolic velocity of basilar artery in dogs by Doppler ultrasonography

This study was performed to examine the influence of isoflurane anesthesia on the pulsatility index (PI) and the peak systolic velocity (PSV) of the blood flow in the basilar artery of dogs by duplex Doppler ultrasonography. Twelve healthy dogs were used to measure the PI and the PSV under the conscious state and isoflurane anesthesia. The pulsatility index (PI) and the peak systolic velocity (PSV) in the basilar artery were measured five times with random intervals. The blood pressure was measured. The PI and PSV values in dogs under isoflurane anesthesia were 1.37 +/- 0.32 and 72 +/- 19 cm/sec, whereas those in the conscious dogs were 1.37 +/- 0.13 and 81 +/- 16 cm/sec, respectively. The indirect mean arterial systolic and diastolic pressures under isoflurane anesthesia were 107 and 51 mmHg, whereas those in the conscious dogs were 133 and 74 mmHg. Though the isoflurane is generally known to induce hypotension, there were no significant differences in the PI and PSV between the isoflurane-anesthetized and the conscious dogs. In conclusion, the isoflurane anesthesia did not influence the PI and PSV in the basilar artery of dogs.

A long-term transdermal nitric oxide donor improves uteroplacental circulation in women with preeclampsia

OBJECTIVE

To determine the effects of long-term transdermal administration (range, 4-30 days; mean +/- SD, 11.1+/-7.2 days) of isosorbide dinitrate, a nitric oxide donor, in preeclamptic women.

METHODS

We studied uterine and fetoplacental circulation of 12 preeclamptic women with oligohydramnios and an elevated pulsatility index in the uterine arteries.

RESULTS

Transdermal isosorbide dinitrate significantly suppressed the blood pressure of patients. Pulsed Doppler ultrasonography revealed that the average pulsatility index in the uterine arteries was significantly reduced by treatment with isosorbide dinitrate (P < .003). The average pulsatility index in the umbilical artery was also significantly reduced (P < .004). Furthermore, the size of the amniotic fluid pocket increased approximately 4-fold by treatment with isosorbide dinitrate.

CONCLUSIONS

Long-term transdermal administration of isosorbide dinitrate improves fetoplacental circulation and may be effective therapy for avoiding maternal hypertension and oligohydramnios in some preeclamptic women.

Effect of postmenopausal oestradiol and dydrogesterone therapy on lipoproteins and insulin sensitivity, secretion and elimination in hysterectomised women

OBJECTIVES

To investigate in depth the metabolic effects of oestradiol-17 beta both alone and in combination with the progestagen dydrogesterone.

METHODS

Fifteen hysterectomised postmenopausal women were studied before treatment and after 24 weeks taking oestradiol-17 beta alone (2 mg per day), then following a further 6 (oestrogen-alone phase) and 12 (oestrogen plus progestagen phase) weeks with inclusion of dydrogesterone (10 mg per day for days 17-28 of each 28 day cycle). Measurements at each visit included fasting serum lipid and lipoprotein concentrations, insulin sensitivity, secretion and elimination by modelling analysis of intravenous glucose tolerance test glucose, insulin and C-peptide concentrations, body fat distribution by dual-energy X-ray absorptiometry (DXA) and arterial function by carotid artery ultrasound.

RESULTS

Significant reductions were seen throughout in total and LDL cholesterol. The net reductions in total and LDL cholesterol by the end of the study were 5.8% (P<0.05) and 18.4% (P<0.001), respectively. HDL and HDL subfraction cholesterol concentrations rose during treatment with oestradiol alone, the rise being primarily in the HDL(2) subfraction (+21.6%, P<0.001). Fasting serum triglycerides rose 30% on oestradiol treatment. These increases were unaffected by the addition of dydrogesterone. Insulin sensitivity, secretion and elimination, body fat distribution and arterial function were not significantly affected at any stage of the therapy.

CONCLUSIONS

The small study sample and high variability in measures of glucose and insulin metabolism may have contributed to the absence of the expected significant improvement in these parameters. Orally administered oestradiol had beneficial effects on total, LDL and HDL cholesterol which were unaffected by the addition of dydrogesterone.

Vasomotor and vascular effects of hormone replacement therapy

Cardiovascular risk factors impair endothelium-dependent vasodilation as well as other functions of the endothelium, thereby predisposing the patient to atherosclerosis and its overt clinical manifestations. Loss of endogenous estrogen also leads to reduced bioavailability of endothelium-derived nitric oxide. In premenopausal women, the impairment of endothelial function develops within 1 month of surgical ovariectomy and is reversed by the administration of exogenous 17 beta-estradiol. Exogenous estrogen administration restores endothelial function by enhancing nitric oxide synthesis through genomic and nongenomic mechanisms and by reducing oxidative stress and nitric oxide breakdown. The effect of progesterone on endothelial function is still under investigation. In animal studies, medroxyprogesterone acetate (MPA) counteracts estrogen's beneficial effects on endothelial function and on coronary plaque size. In humans, however, the addition of progesterone to estradiol does not appreciably attenuate estrogen-associated endothelium-dependent vasodilation. Secondary prevention trials with conjugated equine estrogen plus MPA have no proven benefit in reducing coronary events, progression of angiographic coronary atherosclerosis, or incidence of cerebrovascular events. This suggests that beneficial effects of estrogen on endothelial function are counterbalanced by detrimental effects, perhaps because of proinflammatory and prothrombotic actions. The selective estrogen receptor modulators are currently under investigation as agents that might retain the favorable, without possessing the unfavorable, effects of estrogen on the vascular system.

Effects of oestrogen replacement on steady and pulsatile haemodynamics in ovariectomized rats

1. The effects of ovariectomy (Ovx), menopause and oestrogen replacement on the haemodynamics remain controversial. The present study employed the technique of arterial impedance analysis to measure and calculate the steady and pulsatile haemodynamics. The purpose was to determine the haemodynamic consequence of ovariectomy and oestrogen replacement. 2. Ovariectomy was carried out under anaesthesia on female Sprague Dawley rats aged 9 weeks. Oestrogen (17 beta-estradiol or E(2)) replacement started 1 week after ovariectomy for 4 weeks. Ovx increased the body weight (BW), while it greatly reduced the uterus weight. Left ventricular weight (LVW) was slightly increased, but LVW/BW ratio was slightly reduced. These changes were reversed after E(2) replacement. 3. Compared to sham group, Ovx with or without E(2) replacement did not significantly affect the systolic, mean and diastolic pressure. In Ovx, pulse pressure (PP) and heart rate were significantly increased, while stroke volume and cardiac output were slightly decreased. Total peripheral resistance (TPR) was largely elevated, indicating Ovx induced systemic vasoconstriction. These changes all returned to close normal values (sham group) after E(2) replacement, except PP. 4. Ovx increased the characteristic input impedance (Zc) and pulse wave reflection, while it decreased arterial compliance. E(2) treatment reversed these changes, except Zc. 5. These results demonstrate that Ovx influences both the resistance and Windkessel functions of the artery. E(2) treatment effectively reverses most the effects of Ovx both on the steady and pulsatile haemodynamics.

Regional hemodynamic effects of dopamine in the indomethacin-treated preterm infant

OBJECTIVE

We have previously demonstrated that dopamine induces selective renal vasodilation without affecting cerebral and mesenteric blood flow in < or = 32 weeks' gestation normotensive preterm infants during the first postnatal day. In the present study, we have examined whether pretreatment with indomethacin affects the regional hemodynamic response to dopamine in >1-day-old normotensive preterm infants with similar gestational age.

STUDY DESIGN

The pulsatility index (PI) was used to assess the dopamine-induced changes in renal, mesenteric, and cerebral blood flow using color Doppler ultrasonography in 20 indomethacin-treated normotensive preterm neonates with patent ductus arteriosus (gestational age: 27.2+/-1.5 weeks; postnatal age: 35.7+/-8.2 hours). Dopamine (5 microg/kg per minute) was started 4.9+/-2.1 hours (range: 2 to 8 hours) after the first dose of indomethacin to combat oliguria and/or impaired peripheral perfusion. Blood flow velocity measurements were obtained immediately before and 10 minutes after the start of dopamine with each subject serving as his/her own control.

RESULTS

Dopamine increased heart rate and urine output but did not affect blood pressure at the dose applied. Dopamine decreased the PI in the renal and superior mesenteric artery (2.6+/-1.32 vs. 1.61+/-0.7 and 2.36+/-1.12 vs. 1.76+/-0.64, respectively; p<0.05) whereas the PI in the middle cerebral artery remained unchanged. These results are consistent with a dopamine-induced increase in renal and mesenteric blood flow without an effect on cerebral blood flow.

CONCLUSIONS

When started at least 2 hours after the first dose of indomethacin, dopamine induces renal and mesenteric vasodilation without affecting cerebral hemodynamics in the >1-day-old indomethacin-treated preterm infant.

Effects of GH replacement on endothelial function and large-artery stiffness in GH-deficient adults: a randomized, double-blind, placebo-controlled study

OBJECTIVES

Hypopituitary adults with growth hormone deficiency (GHD) have an increased cardiovascular mortality, although the mechanisms remain unclear. Endothelial dysfunction, characterized by reduced nitric oxide (NO) bioavailability, is a key early event in atherogenesis and is associated with increased vascular smooth muscle tone and arterial stiffening.

DESIGN AND PATIENTS

In a randomized, double-blind, placebo-controlled study, we investigated the effects of GH replacement on endothelial function and large-artery stiffness in 32 GHD adults (19 males, 13 females) (age range 19-64 years) over a 6-month period. Thirty-two age- and sex-matched healthy controls were also studied.

MEASUREMENTS

Endothelial function was assessed using ultrasonic wall tracking to measure flow-mediated dilatation (FMD) of the brachial artery. Large artery stiffness was assessed by pulse wave analysis of the radial artery pressure waveform, allowing determination of the corresponding central arterial pressure waveform and derivation of the augmentation index. Fasting lipid profiles, glucose and insulin were also measured.

RESULTS

At baseline, FMD (mean +/- SD) was impaired in GH-deficient subjects vs. controls (3.4 +/- 2.3 vs. 5.7 +/- 2.0%, P < 0.0001), although endothelium-independent dilatation was similar. The augmentation index was higher in GH-deficient subjects vs. controls (23 +/- 12 vs. 14 +/- 14%, P < 0.01). GH-deficient subjects had higher LDL cholesterol (4.1 +/- 0.8 vs. 3.5 +/- 0.8 mmol/l, P < 0.01) and lower HDL cholesterol (1.1 +/- 0.3 vs. 1.4 +/- 0.4 mmol/l, P < 0.01). In GH-deficient subjects, there were inverse correlations between LDL cholesterol and FMD (r = -0.40, P < 0.05) and between FMD and the augmentation index (r = - 0.58, P < 0.01). Regression analysis identified FMD as an independent predictor of the augmentation index (P < 0.0001). In comparison with baseline, GH replacement resulted in an increase in FMD (5.0 +/- 2.6 vs. 2.8 +/- 1.9%, P < 0.01). There were decreases in central aortic systolic pressure (117 +/- 15 vs. 123 +/- 17 mmHg, P < 0.01), diastolic pressure (82 +/- 10 vs. 86 +/- 8 mmHg, P < 0.01) and the augmentation index (22 +/- 8% vs. 26 +/- 10%, P < 0.05) despite unchanged brachial pressure indices. LDL cholesterol also decreased (3.5 +/- 0.8 vs. 4.2 +/- 0.8 mmol/l, P < 0.01). There were no significant changes in the placebo group.

CONCLUSIONS

Adult GHD is associated with endothelial dysfunction and increased large-artery stiffness. An improvement in endothelial function and a reduction in arterial stiffness following GH replacement suggests an important therapeutic role for GH in reducing cardiovascular risk associated with adult GHD.

Effects of the selective estrogen receptor modulator, raloxifene, on carotid artery pulsatility index in postmenopausal women

OBJECTIVE

Estrogen replacement therapy after menopause reduces the incidence of arterial disease and cerebrovascular events. The reduced incidence also seems to be due to a positive effect of estrogens on brain blood flow as shown by a decrease in the carotid artery pulsatility index. Raloxifene, a second-generation selective estrogen receptor modulator, has aroused considerable interest because of its tissue-specific agonist-antagonist effect on estrogen receptors. However, there have been no studies on the effect of raloxifene on carotid blood flow after menopause.

METHODS

A total of 66 healthy women in postmenopause for more than a year were divided randomly into 2 groups: the first group (n = 33; mean age +/- SD, 53.3 +/- 5.2 years) was treated with raloxifene (one 60-mg capsule per day) for 6 months, and the other group (n = 33; mean age +/- SD, 51.9 +/- 4 years) was untreated. Doppler ultrasonography was used to measure carotid artery pulsatility index (PI) at the beginning of the study and at 2-month intervals.

RESULTS

A reduction in carotid artery PI was observed in all patients receiving raloxifene. No significant changes were observed in the control group. The reduction with respect to baseline values was 6.1%(P <.05) after 2 months, 11.2% (P <.05) after 4 months, and 13.2% (P <.05) after 6 months of therapy. The higher the baseline PI, the greater was its reduction after therapy.

CONCLUSIONS

After 6 months of therapy, raloxifene induced a reduction in PI similar to that reported after estrogen therapy. The present results further our understanding of the mechanisms by which raloxifene might reduce the incidence of cardiovascular disease in postmenopausal women.

Characterization of GH pulsatility in male Shiba goats: effects of postpubertal castration and KP102

The present study was conducted in order to characterize the secretory pattern of GH in the Shiba goat, a native Japanese miniature goat, and to examine the effects of castration and KP102, a GH secretagogue, on this pattern. Blood samples were taken from an indwelling jugular catheter every 15 min for 24 h, and plasma GH was measured by radioimmunoassay. In intact males, GH was secreted in a pulsatile manner with very regular 5-h periodicity, which consisted of a distinctive GH pulse and a trough of virtually no GH secretion. Postpubertal castration increased the height and decreased the width of GH pulses, though it did not affect the interpulse interval and area under the curve. Modification of the shape of each GH pulse by testicular androgen might play a role in the expression of GH action in the male. KP102 (10 microg/kg, i.v.) immediately induced a robust GH pulse, which was followed by a spontaneous GH pulse of normal characteristics at regular intervals, suggesting that the clock generating GH pulses was reset by KP102. From these observations, we concluded that the Shiba goat is a very suitable experimental model for elucidating the mechanisms underlying GH pulse generation, and in particular, the involvement of androgen and GH secretagogues.

The short-term effect of latanoprost on intraocular pressure and pulsatile ocular blood flow

PURPOSE

There is evidence that ocular blood flow plays a critical role in the clinical course of glaucoma. Any reduction in ocular blood flow due to topical antiglaucoma treatment should therefore be avoided. This study aimed to evaluate the short-term effect of local latanoprost application on ocular hemodynamics.

METHODS

Intraocular pressure (IOP), ocular pulse amplitude (OPA), ocular pulse volume (OPV), systemic blood pressure, heart rate and the pulsatile component of ocular blood flow (POBF) were recorded using a pneumotonometer linked to the Langham Ocular Blood Flow System in 24 patients in a prospective, open-label study before and after 1 week of topical latanoprost application in both eyes. Twenty of the subjects had primary open-angle glaucoma and four had ocular hypertension.

RESULTS

After 1 week of latanoprost treatment, IOP decreased significantly 6.2 +/- 2.9 mmHg in OD (P < 0.001) and 6.2 +/- 3.2 mmHg in OS (P < 0.001). Pulsatile OBF increased significantly by 201.2 +/- 167.4 microL/min in OD (P < 0.001) and 203.8 +/- 187.3 microL/min in OS (P < 0.001). Ocular pulse amplitude and OPV showed statistically significant increases (P < 0.05 and P < 0.001 respectively). Blood pressure and heart rate did not change significantly.

CONCLUSION

Our results indicate that 1 week after latanoprost application, POBF, OPA and OPV were significantly increased in the eyes treated. More information on the perfusion of the optic nerve head is needed before the relevance of these findings to optic nerve head blood flow can be interpreted correctly.

Elevated cerebral blood flow velocities in Fabry disease with reversal after enzyme replacement

BACKGROUND AND PURPOSE

Fabry disease is an X-linked inherited disorder resulting from a deficiency of alpha-galactosidase A. Cerebrovascular disease in Fabry disease includes small-vessel disease and larger-vessel ectasia in a predominantly posterior distribution. We assessed transcranial Doppler (TCD) blood flow velocities in naive and enzyme-treated Fabry patients.

METHODS

TCD was used to noninvasively examine patients with Fabry disease for abnormal cerebral blood flow velocities. TCD measurements were also made during CO2 retention by breathholding to examine cerebrovascular vessel reactivity. Twenty-six patients were enrolled in a 6-month, double-blind, placebo-controlled trial of enzyme replacement therapy consisting of biweekly intravenous alpha-galactosidase A infusions, with a subsequent 18-month follow-up in an open-label trial. Statistical analysis consisted of applying a mixed-effects ANOVA model for correlated outcomes.

RESULTS

Peak velocity, mean velocity, pulsatility index, and resistance index were found to be significantly higher in patients compared with control subjects. When the individual vessels were considered, elevated flow velocities were found in the middle cerebral M1 branch and the posterior cerebral artery. Enzyme replacement therapy significantly decreased peak, mean, and end-diastolic velocities and flow acceleration at the 18-month follow-up time point.

CONCLUSIONS

Patients with Fabry disease have elevated cerebral blood flow velocities. These velocities significantly improved with enzyme replacement therapy.

Antropyloroduodenal, cholecystokinin and feeding responses to pulsatile and non-pulsatile intraduodenal lipid infusion

The contribution of the pulsatile nature of gastric emptying to small intestinal feedback mechanisms modulating antropyloroduodenal motility and appetite is unknown. On separate days, eight healthy male volunteers (18-34 years) received randomized, single-blind, intraduodenal (ID) infusions of 10% Intralipid (2 kcal min(-1)), either continuously [CID], or in a pulsatile manner [PID] (5 s on/15 s off) and 0.9% saline (control) administered continuously, each at a rate of 1.8 mL min(-1) for 3 h. During each infusion, subjective ratings of appetite were assessed and antropyloroduodenal pressures recorded with a 16-lumen manometric assembly incorporating a pyloric sleeve sensor. Plasma cholecystokinin was measured from blood collected at regular intervals throughout the infusion. At the end of each infusion the manometric assembly was removed, subjects were offered a buffet meal and the energy and macronutrient content of the meal was measured. Both ID lipid infusions stimulated isolated pyloric pressure waves (IPPWs) (P < 0.001) and basal pyloric pressure (P < 0.01) and suppressed antral (P < 0.05) and duodenal (P < 0.05) pressure waves when compared to controls; there was no difference in the effects of CID and PID lipid on antropyloroduodenal pressures. Infusions of lipid significantly increased plasma CCK concentrations (P < 0.05) compared with saline, but concentrations were not different between the two modes of lipid delivery (P > 0.05, CID vs. PID). Both intraduodenal lipid infusions decreased hunger (P < 0.05), increased fullness (P < 0.05) and reduced energy intake (P < 0.05) when compared with controls; again there was no difference between CID and PID lipid. We conclude that at the infusion rate of similar 2 kcal min(-1), the acute effects of intraduodenal lipid on antropyloroduodenal pressures, plasma CCK concentration and appetite are not modified by a pulsatile mode of lipid delivery into the duodenum.

Pulsatile drug release control using hydrogels

Current research in the field of drug delivery devices, by which pulsed and/or pulsatile release is achieved, has been intensified. In this article several types of drug delivery systems using hydrogels are discussed that showed pulsed and/or pulsatile drug delivery characteristics. As is frequently found in the living body, many vital functions are regulated by pulsed or transient release of bioactive substances at a specific site and time. Thus it is important to develop new drug delivery devices to achieve pulsed delivery of a certain amount of drugs in order to mimic the function of the living systems, while minimizing undesired side effects. Special attention has been given to the thermally responsive poly(N-isopropylacrylamide) and its derivative hydrogels. Thermal stimuli-regulated pulsed drug release is established through the design of drug delivery devices, hydrogels, and micelles. Development of modified alginate gel beads with pulsed drug delivery characteristic is also described in this article.

Doppler velocimetry parameters of periurethral vessels in postmenopausal incontinent women receiving estrogen replacement

Estrogen deficit causes significant alterations in the lower urinary tract of women, largely affecting urinary continence mechanisms. The urethral vascular bed accounts for about one-third of urethral pressure, and as it undergoes marked hormonal influence we became interested in investigating its behaviour both prior to and during estrogen replacement. We selected 25 postmenopausal patients with urinary stress incontinence and studied the periurethral vessels by means of Doppler velocimetry, analyzing the number of vessels, systolic peak, minimum diastole, resistance and pulsatility indexes and the A/B ratio, prior to estrogen replacement and after 1 and 3 months of hormone use. We concluded that estrogen replacement alone in postmenopausal women with urinary stress incontinence increased the number of periurethral vessels, systolic peak and minimum diastole; however, a trend of no statistical significance towards the reduction of resistance and pulsatility rates of periurethral vessels was found; nor was a significant difference in the A/B ratio shown.