P-760 Monozygotic twin rate among IVF centers: A multicenter analysis of data from 18 Italian units

Study question

Could factors inherent to individual centers, related to local clinical or laboratory variables, play a role in the increased incidence of monozygotic twins in IVF?

Summary answer

The rate of MZT did not significantly vary among IVF centers

What is known already

The risk of monozygotic twins (MZT) is increased in couples undergoing in vitro fertilization (IVF). Several systematic reviews have investigated the possible determinants linked to IVF, but results obtained have been inconclusive. Associations have been identified with the prolonged culture at blastocyst stage and young female age. Conventional IVF compared to ICSI, and assisted hatching emerged as possible additional risk factors, but evidence is controversial. Meta-analyses, however, cannot provide robust evidence because of the difficulty in performing multivariate analyses. Moreover, available investigations were retrospective and involved relatively small sample sizes hampering the quality of the collected data.

Study design, size, duration

This is a multicenter retrospective cohort study using the Italian ART National Registry database and involving the Centers reporting data from individual IVF cycles from 2015 to 2019. Eighteen IVF centers were included with a total of 87,076 IVF cycles reported during the study period. The primary aim of the study was to investigate whether the incidence of MZT differed among centers.

Participants/materials, setting, methods

Only single embryo transfer cycles were considered. Women who had sex-discordant twin deliveries were excluded. MZT rate was calculated as the number of multiple pregnancies out of the total number of clinical pregnancies. A binomial distribution model was used to determine the 95% CI of the frequency of MZT. The rates among centers were deemed heterogeneous if the 95% CI in at least one center did not include the mean MZT rate.

Main results and the role of chance

Ten centers reported data from 2015 to 2019, eight from 2017 to 2019. An analysis of the main characteristics of the centers revealed considerable variability. The total number of clinical pregnancies fulfilling our inclusion criteria were 10,440. Of these, 7 were found to be twin pregnancies with discordant gender and were excluded, leaving 10,433 for data analyses. The number of cases included per center varied between 11 and 2,823. Overall, 162 pregnancies were found to be multiple: 48 ended in a miscarriage, 28 spontaneously reduced to singletons and 86 women delivered two or more newborns. The vast majority were twins (n = 160), one was triplet, and one was quadruplet. Considering the denominator of 10,433 pregnancies, the rate of MZT was thus 1.5% (95%CI: 1.3 - 1.8%). The MZT rate among centers varied between 0% (95%CI: 0.0 - 25.9%) and 3.2% (95%CI: 1.3 - 8.1%). All the 95%CIs of the rates of MZT include the 1.5% common rate, thus rejecting the hypothesis that this incidence significantly differed among centers. Spearman correlations between the rate of MZT and variables associated with individual center policies could not identify any significant association. Even when restricting the analyses only to the largest centers, no association emerged.

Limitations, reasons for caution

Our study was limited by its retrospective nature. Furthermore, some centers provided less than 100 cases for data analysis and were therefore poorly informative. External confirmation from larger registries is therefore required.

Wider implications of the findings

This study provides evidences that the rate of MZT did not differ among IVF centers. Furthermore, no clinical and laboratory variables inherent to individual centers were identified in the determinism of IVF-associated MZT. Further studies are needed to identify the causes of increased risk of MZT in IVF practice.

Trial registration number

not applicable

O-156 Fertilization rate as a novel indicator for cumulative live birth rate: multicenter retrospective cohort study of 9,394 complete IVF cycles

Study question

Does fertilization rate (FR) affect cumulative success rates in assisted reproduction cycles?

Summary answer

These data indicate a positive association between FR with CLBR suggesting the predictive clinical relevance of this parameter and its adoption as Key Performance Indicator(KPI).

What is known already

Numerous studies have aimed at characterizing outcome predictors. Maternal age is historically and correctly recognized as the single most important factor impacting on the clinical outcome of ART. More recently ovarian response has also gained interest in this respect. However, the quest for novel, more comprehensive predictive factors is not over; new relevant evidence is starting to emerge. FR is a noteworthy parameter because expressing a fundamental aspect of both oocyte and sperm developmental competence. In fact it has been adopted as a key performance indicator of the IVF laboratory, to assess laboratory, operator, and gamete competence.

Study design, size, duration

Reported data concern a retrospective cohort study carried out between 2015 to 2017 involving 7,968 couples undergoing 9,394 complete ICSI cycles, i.e. whose all embryos were transferred or disposed.All women aged between 18-42 years were included.We excluded from analysis: surgical sperm retrieval cases, cycles resulting in neither fresh or frozen–thawed embryo transfers,cycles in which live birth were not achieved, but with remaining cryopreserved embryos,cycles of PGT, cycle with fertilization failure and standard IVF cycles.

Participants/materials, setting, methods

The cohort was groupped according to fertilization rate intervals based on recommendations of the Vienna Consensus (<65% - Group 1; 65%-80% - Group 2; >80% - Group 3). Harnessing the large size of the original dataset, further cycle stratifications were carried out based on female age (<34, 35-38, 39-42 years) and number of oocytes retrieved (5-7, 8-10, >10 oocytes).

Main results and the role of chance

No significant difference in female age was observed between fertilization rate groups (p = 0.640). CLBR was progressively higher in relation fertilization rate in Groups 1, 2 and 3 (20.1%, 34.7%, 41.3%, P < 0.001, respectively). Number of recovered oocytes, embryo number per cycle, cumulative pregnancy rate followed the same trend (p < 0.001). The decrease in CLBR with increasing female age was significantly correlated with fertilization rate and CLBR in all three female age groups (P < 0.001). Finally, to further control for possible patient-specific confounding factors, maternal age, number of retrieved oocytes, percent of inseminated oocytes and fertilization rate were evaluated in a multivariate logistic regression analysis. From this assessment, fertilization rate emerged as a factor independently associated with cumulative live birth rate, to a degree equivalent or higher compared with the number or retrieved oocytes.

Limitations, reasons for caution

The study design is retrospective and requires further refinement to control for factors that may impact clinical outcome.

Wider implications of the findings

These data indicate a positive association of FR with CLBR, thereby suggesting that fertilization, in addition to representing an assay for gamete quality and laboratory performance,has an independent clinical significance.Irrespective of the number of retrieved oocytes and female age, we observed that, rates of FR are positively associated with CLBR.

Trial registration number

None

Fine tuning by protein kinases of CaV1.2 channel current in rat tail artery myocytes

Seventeen compounds, rather selective, direct or indirect inhibitors and activators of PKA, PKG, and PKC, were analysed for effects on vascular Ca_V1.2 channel current (I_Ca1.2) by using the patch-clamp technique in single rat tail artery myocytes. The aim was to investigate how PKs regulate I_Ca1.2 and disclose any unexpected modulation of Ca_V1.2 channel function by these agents. The cAMP analogues 8-Br-cAMP and 6-Bnz-cAMP partially reduced I_Ca1.2 in dialysed cells, while weakly increasing it under the perforated configuration. The β-adrenoceptor agonist isoproterenol and the adenylate cyclase activator forskolin concentration-dependently increased I_Ca1.2; this effect was reversed by PKA inhibitors H-89 and KT5720, but not by PKI 6-22. The cGMP analogue 8-Br-cGMP, similarly to the NO-donor SNP, moderately reduced I_Ca1.2, this effect being reversed to a slight stimulation under the perforated configuration. Among PKG inhibitors, Rp-8-Br-PET-cGMPS decreased current amplitude in a concentration-dependent manner while Rp-8-Br-cGMPS was ineffective. The non-specific phosphodiesterase inhibitor IBMX increased I_Ca1.2, while H-89, KT5720, and PKI 6-22 antagonized this effect. The PKC activator PMA, but not the diacylglycerol analogue OAG, stimulated I_Ca1.2 in a concentration-dependent manner; conversely, the PKCα inhibitor Gö6976 markedly reduced basal I_Ca1.2 and, similarly to the PKCδ (rottlerin) and PKCε translocation inhibitors antagonised PMA-induced current stimulation. The ensemble of findings indicates that the stimulation of cAMP/PKA, in spite of the paradoxical effect of both 8-Br-cAMP and 6-Bnz-cAMP, or PKC pathways enhanced, while that of cGMP/PKG weakly inhibited I_Ca1.2 in rat tail artery myocytes. Since Rp-8-Br-PET-cGMPS and Gö6976 appeared to block directly Ca_V1.2 channel, their docking to the channel protein was investigated. Both compounds appeared to bind the α_1C subunit in a region involved in Ca_V1.2 channel inactivation, forming an interaction network comparable to that of Ca_V1.2 channel blockers. Therefore, caution should accompany the use of these agents as pharmacological tools to elucidate the mechanism of action of drugs on vascular preparations.

Influence of stomach mucosa tissue on the efficacy of intragastric antibacterial PDT

In the field of photodynamic therapy (PDT), optimization of the in vivo therapeutic efficacy needs a comprehensive study of the photo-killing action spectrum that depends on both the photosensitizer (PS) absorption and the tissue optical properties. This is especially true in the case of gastric infections by Helicobacter pylori: PS absorption has been largely investigated in vitro, while the contribution of tissue optical properties and illumination geometry has been poorly studied, despite being parameters that reflect the specific in vivo conditions. To investigate their influence, we focussed on the case of a point-like light source positioned in the antrum. This models a therapeutic device developed by our team which consists of a LED-based ingestible pill. By a simple 3D illumination model, our approach mediates light-tissue interaction over the illuminated stomach wall surface, then calculates its average transmittance T by means of a 1D model representative of the mean gastric mucosa structure. Finally, by merging T(λ) with the photosensitizers' absorption we obtained the in vivo action spectrum. This shows two peaks at about 500 and 630 nm, indicating a noticeable influence of the tissue with respect to in vitro studies, where the action spectrum reflects PS absorption only. Our approach defines one average action spectrum for this specific therapeutic context, which reflects the need to choose one emission spectrum for the light source used. The proposed methodology could be applied to any other illumination geometry of cave organs, provided appropriate model modifications for the light source and tissue characteristics are made.

TomoTherapy treatments of multiple brain lesions: an in-phantom accuracy evaluation

Aim of the present study was to evaluate the accuracy which can be obtained with helical TomoTherapy^® (HT, Accuray) systems in the case of multiple intracranial targets treatments. Set-up accuracy was measured, for different registration options and MegaVoltage CT (MVCT) slice thickness, by applying known misalignments to an ad-hoc developed phantom. End-to-end (E2E) tests were performed to assess the delivery accuracy in phantoms containing multiple targets by using radiochromic films: measured dose distribution centroids were compared with physical and calculated target positions on axial and coronal planes. A Gamma index analysis was carried out on planned and measured planar dose maps. The bone and tissue algorithm with the fine MVCT reconstruction grid gave the best results among the automatic options. The most accurate registration modality resulted to be the manual one with a sub-voxel accuracy shifts and a capability in the detection of rotations within 0.3°. For the E2E along the coronal plane (six targets), a mean deviation between measured dose distribution centroids and physical barycenters of 0.6 mm (range 0.1 mm-1.3 mm) was observed. Along the axial plane (five targets), a mean deviation of 1.2 mm (range 0.7 mm-2.1 mm) was found for the centroids shifts. Gamma index (5%, 1 mm, local) passing rates higher than 87.5% between planned and delivered dose distributions were measured. These results demonstrate that multiple brain lesion HT treatments are feasible with an accuracy at least comparable to frameless linac-based delivery, when a set-up capable to assure angular corrections and a reliable patient immobilization is employed.

In vitro and in silico analysis of the vascular effects of asymmetrical N,N-bis(alkanol)amine aryl esters, novel multidrug resistance-reverting agents

Asymmetrical N,N-bis(alkanol)amine aryl esters (FRA77, GDE6, and GDE19) are potent multidrug resistance (MDR) reversers. Their structures loosely remind that of the Ca(2+) antagonist verapamil. Therefore, the aim of this study was to investigate their vascular activity in vitro. Their effects on the mechanical activity of fresh and cultured rat aorta rings on Cav1.2 channel current (I Ca1.2) of A7r5 cells and their cytotoxicity on A7r5 and EA.hy926 cells were analyzed. Docking at the rat α1C subunit of the Cav1.2 channel was simulated in silico. Compounds tested were cytotoxic at concentrations >1 μM (FRA77, GDE6, GDE19) and >10 μM (verapamil) in EA.hy926 cells, or >10 μM (FRA77, GDE6, GDE19) and at 100 μM (verapamil) in A7r5 cells. In fresh rings, the three compounds partly antagonized phenylephrine and 60 mM K(+) (K60)-induced contraction at concentrations ≥1 and ≥3 μM, respectively. On the contrary, verapamil fully relaxed rings pre-contracted with both agents. In cultured rings, 10 μM GDE6, GDE19, FRA77, and verapamil significantly reduced the contractile response to both phenylephrine and K60. Similarly to verapamil, the three compounds docked at the α1C subunit, interacting with the same amino acids residues. FRA77, GDE6, and GDE19 inhibited I Ca1.2 with IC50 values 1 order of magnitude higher than that of verapamil. FRA77-, GDE6-, and GDE19-induced vascular effects occurred at concentrations that are at least 1 order of magnitude higher than those effectively reverting MDR. Though an unambiguous divergence between MDR reverting and vascular activity is of overwhelming importance, these findings consistently contribute to the design and synthesis of novel and potent chemosensitizers.

Functional, electrophysiological and molecular docking analysis of the modulation of Cav 1.2 channels in rat vascular myocytes by murrayafoline A

BACKGROUND AND PURPOSE

The carbazole alkaloid murrayafoline A (MuA) enhances contractility and the Ca(2+) currents carried by the Cav 1.2 channels [ICa1.2 ] of rat cardiomyocytes. As only few drugs stimulate ICa1.2 , this study was designed to analyse the effects of MuA on vascular Cav 1.2 channels.

EXPERIMENTAL APPROACH

Vascular activity was assessed on rat aorta rings mounted in organ baths. Cav 1.2 Ba(2+) current [IBa1.2 ] was recorded in single rat aorta and tail artery myocytes by the patch-clamp technique. Docking at a 3D model of the rat, α1c central pore subunit of the Cav 1.2 channel was simulated in silico.

KEY RESULTS

In rat aorta rings MuA, at concentrations ≤14.2 μM, increased 30 mM K(+) -induced tone and shifted the concentration-response curve to K(+) to the left. Conversely, at concentrations >14.2 μM, it relaxed high K(+) depolarized rings and antagonized Bay K 8644-induced contraction. In single myocytes, MuA stimulated IBa1.2 in a concentration-dependent, bell-shaped manner; stimulation was stable, incompletely reversible upon drug washout and accompanied by a leftward shift of the voltage-dependent activation curve. MuA docked at the α1C subunit central pore differently from nifedipine and Bay K 8644, although apparently interacting with the same amino acids of the pocket. Neither Bay K 8644-induced stimulation nor nifedipine-induced block of IBa1.2 was modified by MuA.

CONCLUSIONS AND IMPLICATIONS

Murrayafoline A is a naturally occurring vasoactive agent able to modulate Cav 1.2 channels and dock at the α1C subunit central pore in a manner that differed from that of dihydropyridines.

Effects of near-infrared laser radiation on the survival and inflammatory potential of Candida spp. involved in the pathogenesis of chemotherapy-induced oral mucositis

Candida spp. usually colonize ulcerative lesions of atrophic mucosa in patients with chemotherapy-induced oral mucositis inducing severe inflammation. The spread of antifungal-resistant strains strongly encouraged the search of complementary or alternative therapeutic strategies to cure inflamed mucosa. In this paper, we studied the effects of a near-infrared (NIR) laser system with dual-wavelength emission (808 nm + 904 nm) on the survival and inflammatory potential of C. albicans, C. glabrata, and C. parapsilosis. Laser treatment was performed with a Multiwave Locked System laser. Survival and apoptosis of fungal strains were evaluated by colony-forming units (CFU) counting and annexin V staining. Cytokine production was evaluated by ImmunoPlex array. Laser treatment significantly affected the survival of Candida spp. by inducing apoptosis and induced a lower production of inflammatory cytokines by dendritic cells compared to untreated fungi. No differences in the survival and inflammatory potential were recorded in treated or untreated Saccharomyces cerevisiae cells, used as the control non-pathogenic microorganism. Laser treatment altered the survival and inflammatory potential of pathogenic Candida spp. These data provide experimental support to the use of NIR laser radiation as a co-adjuvant of antifungal therapy in patients with oral mucositis (OM) complicated by Candida infections.

Disease risk assessment by clinical immunology analyses in periparturient dairy cows

A disease prediction system was investigated in a case-control study in the dry period of high-yielding dairy cows. Blood samples of 75 cows from 26 herds were collected before calving between -23 and -33 days (T1) and also between -2 and -6 days (T2) to investigate a panel of clinical immunology and chemistry parameters. Cows with abnormal serum lysozyme and interleukin-6 concentrations showed a greater disease prevalence until the 60th day in milk compared with non-responder cows (P<0.05 and lower at T1). Differences in disease prevalence were observed on the basis of T1 data, and also by combining the results at T1 and T2. The other laboratory parameters under study were not predictive of a disease risk. Results indicate that environmental stressors in the dry period may cause a negative imprinting of the innate immune response, underlying predisposition to later disease occurrence.

L-type Ca(2+) channel current characteristics are preserved in rat tail artery myocytes after one-day storage

AIM

To develop a cheap and simple method of storing for 24-h vascular tissue and single myocytes while preserving therein the biophysical and pharmacological characteristics of L-type Ca(2+) channels and contractile activity.

METHODS

Rings or vascular smooth muscle cells obtained from the rat tail main artery were used either freshly (R0h and VSMC0h) or stored for 24 h (R24h and VSMC24h) at 4 °C, to record whole-cell L-type Ca(2+) currents (IC a(L) ) or measure contractile responses.

RESULTS

R0h/VSMC0h and R24h/VSMC24h comparably contracted when stimulated with phenylephrine, high KCl or ATP. In both VSMC0h and VSMC24h, IC a(L) was identified and characterized as a stable inward current for at least 35 min; IC a(L) was comparably inhibited by the Ca(2+) antagonists nifedipine, verapamil and diltiazem and increased by the Ca(2+) channel agonist (S)-(-)-Bay K 8644; current density and current-voltage relationships were similar; at more hyperpolarized holding potentials, IC a(L) intensity increased comparably; nifedipine shifted the steady-state inactivation curve towards more negative potentials, while verapamil blocked IC a(L) in a frequency-dependent manner and slowed down the rate of recovery from inactivation in a comparable way.

CONCLUSION

Findings show that smooth muscle contractile activity and the biophysical and pharmacological features of L-type Ca(2+) channels are similar in VSMC24h and VSMC0h. The fact that reproducible results were obtained in vascular myocytes up to 24 h after dissociation may facilitate vascular smooth muscle cell investigation by increasing throughput and reducing the number of animals required.

Quercetin relaxes rat tail main artery partly via a PKG-mediated stimulation of KCa 1.1 channels

AIM

Protein kinases, activated by vasodilator substances, affect vascular function by regulating large conductance Ca(2+) -activated K(+) (KCa 1.1) channels. Thus, the aim of the present investigation was to address the hypothesis that quercetin-induced vasorelaxation is caused by a PKG-mediated stimulation of KCa 1.1 currents.

METHODS

Single freshly isolated myocytes and endothelium-denuded rings of the rat tail main artery were employed for electrophysiological and contractility measurements respectively.

RESULTS

Quercetin relaxed vessels and increased KCa 1.1 currents in a concentration-dependent manner: both effects were antagonized by the specific KCa 1.1 channel blocker iberiotoxin. Stimulation of KCa 1.1 currents was fully reversible upon drug washout, markedly reduced by Rp-8-Br-PET-cGMPs, a PKG-inhibitor, but not affected by catalase. Quercetin shifted by 34.3 mV the voltage dependence of KCa 1.1 channel activation towards more negative membrane potentials without affecting its slope. Under conditions of tight functional coupling between sarcoplasmic reticulum Ca(2+) release sites and KCa 1.1 channels, quercetin decreased both the frequency and the amplitude of KCa 1.1 transient currents in a ryanodine-like manner.

CONCLUSION

The natural flavonoid quercetin relaxes the rat tail main artery partly via a PKG-mediated stimulation of smooth muscle KC a 1.1 channels.

Non invasive continuous hemodynamic evaluation of cirrhotic patients after postural challenge

AIM

To assess whether Most Care is able to detect the cardiovascular alterations in response to physiological stress (posture).

METHODS

Non invasive hemodynamic was assessed in 26 cirrhotic patients compared to healthy subjects, both in the supine and standing positions.

RESULTS

In baseline conditions, when compared to healthy subjects, cirrhotic patients showed significantly lower values of dicrotic and diastolic pressures and systemic vascular resistance. While in the standing position, cirrhotic patients showed higher values of cardiac index, stroke volume index and cardiac cycle efficiency. When returning to the supine position, cirrhotic patients exhibited lower values of dicrotic and diastolic pressures and systemic vascular resistance in the presence of higher values of cardiac index, stroke volume index and cardiac cycle efficiency.

CONCLUSION

Most Care proved to be able to detect cardiovascular abnormalities bedside in the resting state and after postural challenge in cirrhotic patients.

The flavonoid scaffold as a template for the design of modulators of the vascular Ca(v) 1.2 channels

BACKGROUND AND PURPOSE

Previous studies have pointed to the plant flavonoids myricetin and quercetin as two structurally related stimulators of vascular Ca(v) 1.2 channel current (I(Ca1.2) ). Here we have tested the proposition that the flavonoid structure confers the ability to modulate Ca(v) 1.2 channels.

EXPERIMENTAL APPROACH

Twenty-four flavonoids were analysed for their effects on I(Ca1.2) in rat tail artery myocytes, using the whole-cell patch-clamp method.

KEY RESULTS

Most of the flavonoids stimulated or inhibited I(Ca1.2) in a concentration- and voltage-dependent manner with EC(50) values ranging between 4.4 µM (kaempferol) and 16.0 µM (myricetin) for the stimulators and IC(50) values between 13.4 µM (galangin) and 100 µM [(±)-naringenin] for the inhibitors. Key structural requirements for I(Ca1.2) stimulatory activity were the double bond between C2 and C3 and the hydroxylation pattern on the flavonoid scaffold, the latter also determining the molecular charge, as shown by molecular modelling techniques. Absence of OH groups in the B ring was key in I(Ca1.2) inhibition. The functional interaction between quercetin and either the stimulator myricetin or the antagonists resokaempferol, crysin, genistein, and 5,7,2'-trihydroxyflavone revealed that quercetin expressed the highest apparent affinity, in the low µM range, for Ca(v) 1.2 channels. Neither protein tyrosine kinase nor protein kinase Cα were involved in quercetin-induced stimulation of I(Ca1.2).

CONCLUSIONS AND IMPLICATIONS

Quercetin-like plant flavonoids were active on vascular Ca(v)1.2 channels. Thus, the flavonoid scaffold may be a template for the design of novel modulators of vascular smooth muscle Ca(v)1.2 channels, valuable for the treatment of hypertension and stroke.

Epigenetic analysis of the critical region I for premature ovarian failure: demonstration of a highly heterochromatic domain on the long arm of the mammalian X chromosome

BACKGROUND

X chromosome rearrangements defined a critical region for premature ovarian failure (POF) that extended for >15 Mb in Xq. It has been shown previously that the region could be divided into two functionally distinct portions and suggested that balanced translocations interrupting its proximal part, critical region 1 (CR1), could be responsible for POF through downregulation of ovary expressed autosomal genes translocated to the X chromosome.

RESULTS AND CONCLUSION

This study reports that such position effect can indeed be demonstrated by analysis of breakpoint regions in somatic cells of POF patients and by the finding that CR1 has a highly heterochromatic organisation, very different from that of the euchromatic autosomal regions involved in the rearrangements. The chromatin organisation of the POF CR1 is likely to be responsible for the epigenetic modifications observed in POF patients. The characteristics of CR1 and its downregulation in oocytes may very well explain its role in POF and the frequency of the POF phenotype in chromosomal rearrangements involving Xq. This study also demonstrates a large and evolutionary conserved domain of the long arm of the X chromosome, largely corresponding to CR1, that may have structural or functional roles, in oocyte maturation or in X chromosome inactivation.

(+/-)-Naringenin as large conductance Ca(2+)-activated K+ (BKCa) channel opener in vascular smooth muscle cells

BACKGROUND AND PURPOSE. The aim of this study was to investigate, in vascular smooth muscle cells, the mechanical and electrophysiological effects of (+/-)-naringenin.

EXPERIMENTAL APPROACH

Aorta ring preparations and single tail artery myocytes were employed for functional and patch-clamp experiments, respectively.

KEY RESULTS

(+/-)-Naringenin induced concentration-dependent relaxation in endothelium-denuded rat aortic rings pre-contracted with either 20 mM KCl or noradrenaline (pIC(50) values of 4.74 and 4.68, respectively). Tetraethylammonium, iberiotoxin, 4-aminopyridine and 60 mM KCl antagonised (+/-)-naringenin-induced vasorelaxation, while glibenclamide did not produce any significant antagonism. Naringin [(+/-)-naringenin 7-beta-neohesperidoside] caused a concentration-dependent relaxation of rings pre-contracted with 20 mM KCl, although its potency and efficacy were significantly lower than those of (+/-)-naringenin. In rat tail artery myocytes, (+/-)-naringenin increased large conductance Ca(2+)-activated K(+) (BK(Ca)) currents in a concentration-dependent manner; this stimulation was iberiotoxin-sensitive and fully reversible upon drug wash-out. (+/-)-Naringenin accelerated the activation kinetics of BK(Ca) current, shifted, by 22 mV, the voltage dependence of the activation curve to more negative potentials, and decreased the slope of activation. (+/-)-Naringenin-induced stimulation of BK(Ca) current was insensitive either to changes in the intracellular Ca(2+) concentration or to the presence, in the pipette solution, of the fast Ca(2+) chelator BAPTA. However, such stimulation was diminished when the K(+) gradient across the membrane was reduced.

CONCLUSIONS AND IMPLICATIONS

The vasorelaxant effect of the naturally-occurring flavonoid (+/-)-naringenin on endothelium-denuded vessels was due to the activation of BK(Ca) channels in myocytes.

Cancer Cell Permeability-Glycoprotein as a Target of MDR Reverters: Possible Role of Novel Dihydropyridine Derivatives

The overexpression of permeability-glycoprotein (P-gp) and other drug transporters (ATP-binding cassette) confers a multidrug resistance (MDR) phenotype on cells in various diseases, including many forms of cancer. Development of MDR is one of the main reasons of failure in malignant tumour chemotherapy, as tumour cells, by increasing drug efflux, acquire cross-resistance to many structurally and functionally unrelated anticancer agents, which therefore never achieve effective intracellular concentrations. Endeavouring to find MDR-reverters is a crucial task for exploring new anti-cancer therapeutic intervention. Although many P-gp inhibitors have so far been identified, it is widely recognised that their interaction with P-gp is a complex process and, presently, the details of the mechanisms of action are still a matter of debate. These compounds turned out, however, to be of limited clinical usefulness owing to their inherent pharmacological activities (first generation compounds) and their accessory, inhibiting activity on CYP enzyme system (second generation compounds). Moreover, recent advances of the knowledge on P-gp structure and function and on the mechanisms of P-gp inhibition will prove fruitful for the development of novel therapeutically effective P-gp inhibitors. A dibenzoyl-1,4-dihydropyridine compound (DP7) has been shown to be a powerful P-gp inhibitor, almost devoid of cardiovascular effects, but capable of inhibiting liver CYP3A. DP7 is considered a lead compound for the development of novel dihydropyridines which do not affect CYP enzyme system but still retain the activity towards ABC-efflux transporters.

Open epididymal sperm aspiration (OESA): minimally invasive surgical technique for sperm retrieval

OBJECTIVES

Male infertility caused by irreparable obstructive azoospermia is widely treated with MESA (Microsurgical Epididymal Sperm Aspiration) or TESE (Testicular Sperm Extraction) or PESA (Percutaneous Epididymal Sperm Aspiration) followed by an Intracytoplasmatic Spermatozoa Injection (ICSI). For each procedures are claimed advantages and disadvantages. Aim of this work is to describe our technique (OESA) for sperm retrieval reporting the results.

METHODS

From 1998 to 2003 153 sperm retrieval procedures in azoospermic patients were performed. The technique consists in a small (1 cm.) surgical incision of scrotal wall under local or spinal anaesthesia. After inspecting the intrascrotal component to record the status of the epididymis and of the testicle, epididymal sperm aspiration was performed in the most appropriate site with 18 gauge needle. The aspirated spermatozoa were used immediately after aspiration not being permitted in our Institute cryopreservation. When no sperms were found TESE was performed.

RESULTS

In 78 cases aspiration from epididymis was successful (OESA). In the other patients (75) TESE was performed. Higher count of spermatozoa were retrieved in all cases of OESA. Pregnancy rate was 26.6% for OESA and 6.4% for TESE. No complications occurred.

CONCLUSIONS

This technique is very simple and easy allowing to obtain the advantages of microsurgical techniques (mainly choice of the most appropriate site of aspiration and immediate haemostasis if needed) with minimal invasivity (avoiding epididymal surgical incision). Moreover if OESA does not allow sperm extraction is possible to perform immediately TESE.

Pharmacokinetics of diphenhydramine in healthy volunteers with a dimenhydrinate 25 mg chewing gum formulation

This pharmacokinetic study evaluated diphenhydramine in the plasma of healthy volunteers after a single 25 mg oral dose of dimenhydrinate (diphenhydramine theophyllinate), corresponding to 12.7 mg diphenhydramine, in a chewing gum formulation. Seven volunteers (4 men, 3 women; age: 26.3 +/- 1.2 years; body weight: 63.1 +/- 4.1 kg; height: 172.4 +/- 4.6 cm) chewed the gum for 1 h. Blood samples (10 ml) were collected at different time intervals up to 24 h. Blood plasma was subsequently processed and analyzed for diphenhydramine content using a GLC method and an NPD detector. Analytical data revealed the following kinetic parameters: AUC(0-24h): 155.2h x ng x ml(-1); AUC(0-infinity): 195.3 h x ng x ml(-1); Mean resident time: 16 h; t(1/2): 10 h; C(max): 14.5 ng x ml(-1); t(max): 2.6 h; and plasma clearance: 9.0 ml x min(-1) x kg(-1). This study indicates that the pharmaceutical formulation employed provided sustained plasma concentrations of diphenhydramine, presumably sufficient to support its clinical efficacy towards motion sickness owing to the almost complete (> 95%) release by the formulation of the active principle. Moreover, the maximal concentrations of diphenhydramine attained in plasma were much lower than the concentration threshold needed to produce drowsiness.

Gravitational unloading induces osteoclast-like differentiation of FLG 29.1 cells

FLG 29.1 cells, cultured at 1xg, are able to switch on a differentiating process only when they are suitably induced by chemical factors. On the contrary, when FLG 29.1 cells are cultured in conditions of gravitational unloading, simulated by a Random Positioning Machine, the switching on of the differentiation process occurs in the absence of any added differentiating agent or any stimulating factor. The phenotypic characterization of the cells and quantitative measures of their bone resorption activity are consistent with a differentiation process through the osteoclastic pathway.

The mitochondrial permeability transition and taurine

Perturbed cellular calcium homeostasis has been implicated in both apoptosis and necrosis, but the role of altered mitochondrial calcium handling in the cell death process is unclear. Recently we found that taurine, a naturally occurring amino acid potentiates Ca2+ sequestration by rat liver mitochondria. These data, which accounted for the taurine antagonism on Ca2+ release induced by the neurotoxins 1-methyl-4-phenylpyridinium plus 6-hydroxy dopamine previously reported, prompted us to investigate the effects of taurine on the permeability transition (PT) induced experimentally by high Ca2+ plus phosphate concentrations. The parameters used to measure the PT were, mitochondrial swelling, cytochrome c release and membrane potential changes. The results showed that, whereas taurine failed to reverse changes of these parameters, cyclosporin A completely reversed them. Even though these results exclude a role in PT regulation under such gross insult conditions, they cannot exclude an important role for taurine in controlling pore-opening under milder more physiological PT-inducing conditions.

The possible role of taurine and GABA as endogenous cryogens in the rabbit: changes in CSF levels in heat-stress

We investigated whether heat-stress induced hyperthermia could enhance release of both endogenous taurine and GABA from nerve cells into the extracellular compartment, thus acting like endogenous cryogens. Conscious rabbits were exposed for 1 hr to 40 degrees C (heat stress) while cerebrospinal fluid (CSF) and plasma osmolality and the CSF concentrations of some cations, proteins as well as those of taurine and GABA were determined. Heat stress-induced hyperthermia was accompanied by a significant rise in CSF and plasma osmolality, CSF calcium, taurine and GABA levels. It is suggested that during heat stress taurine and GABA are released in the extracellular space of brain tissues in higher amounts, as compared to control conditions, to counteract the resulting hyperthermia, thus acting as cryogenic agents.

3,5-di-t-butyl-4-hydroxyanisole (DTBHA) activation of rat skeletal muscle sarcoplasmic reticulum Ca(2+)-ATPase

3,5-Di-t-butyl-4-hydroxyanisole (DTBHA) increased in a concentration-dependent manner (calculated pEC(50) = 4.55 +/- 0.18 M) the oxalate-stimulated Ca(2+)-pumping rate of rat skeletal muscle sarcoplasmic reticulum (SR) vesicles. Kinetic analysis of this effect suggested that the activation of SR Ca(2+)-ATPase operated by (DTBHA) was of both mixed and non-competitive type with respect to ATP in the range of concentrations 0.1-0.5 mM and above 1 mM, respectively; furthermore, it was independent of the free Ca(2+) concentrations. This indicated that the enzyme activation took place through the acceleration of the enzyme-substrate complex breakdown. Moreover, it appeared that its target site was cyclopiazonic acid sensitive. The uncommon ability of (DTBHA) to upregulate SR Ca(2+) uptake is of interest in view of its possible use for treating pathological conditions characterised by cell Ca(2+) overload as well as genetic disorders where SR Ca(2+) homeostasis is altered.

Characterization of voltage-gated calcium currents in freshly isolated smooth muscle cells from rat tail main artery

The aim of the present study was to characterize voltage-gated Ca2+ currents in smooth muscle cells freshly isolated from rat tail main artery in the presence of 5 mmol L(-1) external Ca2+. Calcium currents were identified on the basis of their voltage dependencies and sensitivity to nifedipine, Ni2+ and cinnarizine. In the majority of the cells studied, T- and L-type currents were observed, while the remaining cells showed predominantly L-type currents. In the latter group of cells, holding potential change from -50 to either -70 or -90 mV increased the corresponding inward current amplitude while its voltage activation threshold remained unchanged. The steady state inactivation of L-type Ca2+ channels showed half-maximal inactivation at -38 mV. A Ca2+-dependent inactivation was also evident. Nifedipine (3 micromol L(-1)) blocked L-type but not T-type Ca2+ currents. Ni2+ (50 micromol L(-1)) as well as cinnarizine (1 micromol L(-1)) suppressed the nifedipine-resistant, T-type component of the currents. At higher concentrations, both Ni2+ (0.3-1 mmol L(-1)) and cinnarizine (10 micromol L(-1)) blocked the net inward current. Replacement of Ca2+ with 10 mmol L(-)1 Ba2+ significantly increased the amplitude of L-type Ca2+ currents. These results demonstrate that smooth muscle cells freshly isolated from rat tail main artery may be divided into two populations, one expressing both L- and T-type and the other only L-type Ca2+ channels. Furthermore, this report shows that in arterial smooth muscle cells cinnarizine potently inhibited T-type currents at low concentrations (1 micromol L(-1)) but also blocked L-type Ca2+ currents at higher concentrations (10 micromol L(-1)).

Neuroprotection afforded by some hindered phenols and alpha-tocopherol in guinea-pig detrusor strips subjected to anoxia-glucopenia and reperfusion-like conditions

2-t-butyl-4-methoxyphenol (BHA), 3,5-di-t-butyl-hydroxyanisole (DTBHA), 2,6-diisopropylphenol (propofol), alpha-tocopherol (alpha-TOC) and two newly synthesised analogues of BHA, namely 1-O-(4-hydroxy-3-t-butyl)phenyl-2,3,4,6-tetra-O-acetyl-beta-D-glucopyranose (beta-TAG) and 1-O-(4-hydroxy-3-t-butyl)phenyl-beta-D-glucopyranose (beta-GLU), were tested for their capability to protect the intrinsic nerves of guinea-pig urinary bladder from damage due to anoxia-glucopenia and re-exposure to glucose and O2. Guinea-pig detrusor strips were mounted for tension recording in small organ baths, superfused with warmed Krebs solution and the nerves stimulated electrically either under control or ischaemia-like (anoxia-glucopenia) and reperfusion-like conditions (normal medium re-superfusion). The Ca2+ antagonist activity of the compounds was assessed by their effect on the contraction of detrusor strips induced by 60 mM K+ Krebs solution in the presence of either 0.5 mM or 5 mM Ca2+. The antioxidant activity was illustrated by the ability of the compounds to scavenge peroxyl radicals generated by linoleic acid oxidation. All the compounds, except beta-GLU and alpha-TOC, inhibited in a concentration-dependent manner K+-induced contractions of detrusor muscles, the inhibition being inversely related to the Ca2+ concentration of the perfusion solution; moreover, they exhibited a marked antiperoxidant activity with pIC50 values decreasing in the order: DTBHA > alpha-TOC > BHA > beta-TAG > propofol > beta-GLU. alpha-TOC, BHA, DTBHA and beta-TAG improved significantly the response of the strips to electrical field stimulation either during the anoxia-glucopenia phase or thereafter when recovering during reperfusion, as compared to untreated tissues. The neuroprotection afforded by the phenol derivatives as well as by alpha-TOC was positively correlated to their antioxidant activity, but not to their Ca2+ antagonist activity.

2,5-Di-t-butyl-1,4-benzohydroquinone (BHQ) inhibits vascular L-type Ca(2+) channel via superoxide anion generation

The aim of the present study was to investigate the effects of 2,5-di-t-butyl-1,4-benzohydroquinone (BHQ), an inhibitor of the sarco-endoplasmic reticulum Ca(2+)-ATPase (SERCA), on the whole-cell voltage-dependent L-type Ca(2+) current (I(Ca(L))) of freshly isolated smooth muscle cells from the rat tail artery using the patch-clamp technique. BHQ, added to the perfusion solution, reduced I(Ca(L)) in a concentration- (IC(50)=66.7 microM) and voltage-dependent manner. This inhibition was only partially reversible. BHQ shifted the voltage dependence of the steady-state inactivation curve to more negative potentials by 7 mV in the mid-potential of the curve, without affecting the activation curve as well as the time course of I(Ca(L)) inactivation. Preincubation of the cells either with 10 microM cyclopiazonic acid, a SERCA inhibitor, or with 3 mM diethyldithiocarbamate, an inhibitor of intracellular superoxide dismutase (SOD), did not modify BHQ inhibition of I(Ca(L)). On the contrary, this effect was no longer evident when SOD (250 u ml(-1)) was added to the perfusion medium. Either in the presence or in the absence of cells, BHQ gave rise to superoxide anion formation, which was markedly inhibited by the addition of SOD. These results indicate that, at micromolar concentrations, BHQ inhibits vascular I(Ca(L)) by giving rise to the formation of superoxide anion which in turn impairs the channel function.

Effects of some sterically hindered phenols on whole-cell Ca(2+) current of guinea-pig gastric fundus smooth muscle cells

1. The aim of the present study was to investigate the effects of extracellular application of some sterically-hindered phenols, namely 3-t-butyl-4-hydroxyanisole (BHA), 3,5-di-t-butyl-4-hydroxyanisole (DTBHA) and the dimer of BHA, 2,2'-dihydroxy-3,3'-di-t-butyl-5,5'-dimethoxydiphenyl (DIBHA), on the whole-cell Ca(2+) current (I(Ca)) of freshly isolated smooth muscle cells from the guinea-pig gastric fundus, in the presence of a range of Ca(2+) concentrations (1 -- 5 mM) using the patch-clamp technique. The influx of Ca(2+) had characteristics of L-type I(Ca) (I(Ca(L))). 2. BHA as well as DTBHA inhibited I(Ca(L)) in a concentration-dependent manner, during depolarization to 10 mV from a holding potential of -50 mV. Bath application of BHA (50 microM) and DTBHA (30 microM) decreased I(Ca(L)) by 48.9% and 45.2%, respectively. This inhibition was only partially reversible. In contrast, DIBHA (up to 50 microM) was devoided of effects on I(Ca(L)). 3. BHA inhibition of I(Ca(L)) was voltage-dependent and inversely related to the external concentration of Ca(2+). On the other hand, DTBHA inhibition was only voltage-dependent. 4. BHA and DTBHA shifted the voltage range of the steady-state inactivation curve to more negative potentials by 8 mV at the mid-potential of the curve, without affecting the activation curve. Furthermore, BHA and DTBHA did not modify the time-course of the current decay. 5. We conclude that the inhibition of I(Ca(L)) by BHA and DTBHA is qualitatively similar to that of a Ca(2+) channel blocker and is characterized by the stabilizing effect of the inactivated state of the channel.

Heat-stress-induced hyperthermia alters CSF osmolality and composition in conscious rabbits

Amino acids have received increased attention with regard to their thermoregulatory effects and possible role as neurotransmitters within the thermoregulatory system. The purpose of the present work was to evaluate in conscious rabbits the changes in cerebrospinal fluid (CSF) concentration of taurine, GABA, aspartate, and glutamate during exposure to high ambient temperature (50 min, 40 degrees C) to investigate their involvement in heat stress (HS). CSF and plasma osmolality and CSF concentrations of some cations and proteins were also determined. HS animals underwent transient hyperthermia and thereafter fully recovered. This was accompanied by a significant rise in CSF and plasma osmolality, CSF protein, calcium, taurine, and GABA. Artificial CSF osmolality measurements after addition of CaCl(2) or taurine demonstrated that the increased CSF osmolality after HS is accounted for, only in part, by the increased concentrations of either calcium and taurine. It is suggested that, during HS, taurine and GABA are released in the extracellular space of brain tissues in higher amounts, possibly to counteract the resulting hyperthermia.

Multispectral imaging autofluorescence microscopy for the analysis of lymph-node tissues

Although histochemical and immunohistochemical methods are the standard procedures in diagnosis of lymphoproliferative disorders, useful improvements in evidencing histopathologic manifestations can be obtained with the introduction of tissue autofluorescence analyses. We used microspectrofluorometry and a Multispectral Imaging Autofluorescence Microscopy (MIAM) technique to analyze lymph-node biopsies from patients with lymphoadenopathy of different origins. Images of tissue autofluorescence were obtained by excitation at 365 nm of lymph-node sections and sequential detection with interference filters (50 nm bandwidth) peaked at 450, 550 and 658 nm. Monochrome images were combined together in a single red-green-blue color image. Most of the fluorescence was observed within the blue spectral band because of large contributions from extracellular collagen and elastin fibers as well as from reduced form of intracellular nicotinamide adenine dinucleotide (phosphate). Autofluorescence imaging shows morphological differences between neoplastic and non-neoplastic tissues. The reactive hyperplasia samples show the typical lymph-node organization with weak fluorescent follicles separated by high fluorescent connective trabeculae. In the neoplastic lymph nodes the loss of follicle organization is observed. Consequently, MIAM permits to discriminate between non-neoplastic and neoplastic tissues on the basis of their autofluorescence pattern. Multispectral imaging of tissue autofluorescence may present some advantages with respect to standard histochemical microscopy since it (1) does not require any chemical manipulation of samples; (2) gives real-time results performing the analysis immediately upon specimen resection; and (3) supplies a representation of the biological structure organization linked to endogenous fluorophores.

On the mechanisms of the antispasmodic action of some hindered phenols in rat aorta rings

The antispasmodic effects of 3-t-butyl-4-hydroxyanisole (BHA) and some structurally related compounds were investigated in endothelium-intact rat aorta rings. Nordihydroguaieretic acid (NDGA), BHA, 3,5-di-t-butyl-4-hydroxyanisole (DTBHA), 2,6-di-isopropyl phenol (propofol) and 2,2'-dihydroxy-3,3'-di-t-butyl-5, 5'-dimethoxydiphenyl (DIBHA) did not cause relaxation when added at the plateau of phenylephrine-evoked contraction, nor did they affect the concentration-relaxation curve for acetylcholine in precontracted rings. In rings depolarised with physiological salt solution (PSS) containing 40 mM K(+), NDGA, BHA, DTBHA, 2, 5-di-t-butyl-1,4-benzohydroquinone (BHQ), propofol and nifedipine, but not DIBHA, inhibited the contraction induced by cumulative addition of Ca(2+) (0.05-10 mM) in a concentration-dependent manner; this inhibition was inversely related to the Ca(2+) concentration. In 40 mM K(+) PSS, 25 nM nifedipine blocked the 1 mM Ca(2+)-induced contraction, whereas 50 microM DTBHA, NDGA, BHA, BHQ and propofol significantly antagonised it by 84.4%, 73.0%, 52.8%, 45.6% and 35.7%, respectively. In the presence of 1 microM methyl-1,4-dihydro-2, 6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)-pyridine-5-carboxylate (Bay K 8644), the response to Ca(2+) did not differ from control values with nifedipine and BHQ, was partially restored with DTBHA and NDGA, and was not affected with BHA and propofol. Nifedipine markedly inhibited (85.2%) the Ba(2+)-induced contraction and this effect was totally reversed by Bay K 8644. BHA and DTBHA showed antispasmodic activity (45.3% and 43.1%, respectively) which was partly reversed by Bay K 8644. In contrast, Bay K 8644 did not affect the inhibition exerted by BHQ, NDGA and propofol (69.5%, 53. 3% and 46.1%, respectively). Nifedipine, BHA, DTBHA, propofol and NDGA inhibited the contractile response to 1 mM Ca(2+) of aorta rings depolarised with 40 or 80 mM K(+) PSS to a similar extent. Cromakalim inhibited the Ca(2+)-evoked contraction only in 30 mM K(+) PSS and BHQ only in 80 mM K(+) PSS. DIBHA had no effect on this model. Cromakalim, but not BHA, stimulated 86Rb(+) efflux from ring preparations. In 80 mM K(+) PSS containing 1 microM nifedipine, only papaverine affected the phenylephrine-induced contraction. Moreover, when the rings were preincubated with 1 mM Ni(2+), the response to phenylephrine in the presence of BHQ was significantly reduced. In conclusion, we propose that BHA may non-specifically inhibit Ca(2+) influx at the plasmalemma level rather than affect the function of K(+) channels, Ca(2+) release from intracellular stores or endothelium-dependent relaxation.

Cytochrome P450-dependent N-dealkylation of L-deprenyl in C57BL mouse liver microsomes: effects of in vivo pretreatment with ethanol, phenobarbital, beta-naphthoflavone and L-deprenyl

The monoamine oxidase inhibitor L-deprenyl [(-)-deprenyl, selegiline] is an effective therapeutic agent for improving early symptoms of idiopathic Parkinson's disease. It appears to exert this action independently of its inhibition of monoamine oxidase B (MAO-B) and some of its metabolites are thought to contribute. Cytochrome P450 (CYP) activities are known to give rise to L-deprenyl metabolites that may affect the dopaminergic system. In order to clarify the interactions of L-deprenyl with these enzymes, C57BL mice were treated with L-deprenyl, ethanol, phenobarbital or beta-naphthoflavone to induce different CYP isozymes. After preincubation of L-deprenyl with liver microsomes from control or treated mice, the metabolites were analysed by a GLC method. L-deprenyl (10 mg/kg i.p. for 3 days) caused a significant decrease in total CYP levels (0.315+/-0.019, L-deprenyl; 0.786+/-0.124, control, nmol/mg protein) and CYP2E1-associated p-nitrophenol hydroxylase activity (0.92+/-0.04 vs. 1.17+/-0.06 nmol/min/mg). Both phenobarbital and ethanol increased the N-depropynylation activity towards L-deprenyl that leads to the formation of methamphetamine (4. 11+/-0.64, phenobarbital; 4.77+/-1.15, ethanol; 1.77+/-0.34, control, nmol/min/mg). Ethanol alone increased the N-demethylation rate of L-deprenyl, that results in formation of nordeprenyl (3.99+/-0.68, ethanol; 1.41+/-0.31, control, nmol/min/mg). Moreover, the N-dealkylation pathways of deprenyl are inhibited by 4-methylpyrazole and disulfiram, two CYP2E1 inhibitors. None of the other treatments modified L-deprenyl metabolism. These findings indicate that mainly CYP2E1 and to a lesser extent CYP2B isozymes are involved in L-deprenyl metabolism. They also suggest that, by reducing CYP content, L-deprenyl treatment may impair the metabolic disposition of other drugs given in combination regimens.

[Drug adverse effects in the elderly hospitalized with acute pathologies]

OBJECTIVES

Data of Literature suggest that age is not an independent risk factor for adverse drug reactions (ADR), while there is evidence of a positive correlation between ADR and the number of drug taken. To investigate if that is true, we have examined the occurrence of ADR in elderly patients admitted to our Geriatric Department in the first nine months of 1999 for acute illness.

MATERIALS AND METHODS

We have evaluated the occurrence of ADR in 510 patients more than 65 years of age (80 +/- 7.35 years). The adverse drug effect was worth considering when symptomatical or caused a change in the management of the patient (suspension or change of therapy, prolongation of staying in hospital). We used the algorithm of Naranjo (19) to estimate the probability that a drug caused an ADR.

RESULTS AND CONCLUSIONS

In our study the frequency of ADR was 12.5%. Furosemide was responsible for 50% and digoxin for 8% of ADR. Among the patients taking furosemide, 12.5% had an ADR (generally low potassium). The frequency of ADR was correlated neither with the age of the subjects nor with the number of drug taken. It can be possible that the main cause of ADR is the type of drugs assumed by elderly.

Potentiation of mitochondrial Ca2+ sequestration by taurine

The effects of taurine (2-aminoethanesulphonic acid) and its analogues, 2-aminoethylarsonic acid, 2-hydroxyethanesulphonic (isethionic) acid, 3-aminopropanesulphonic acid, 2-aminoethylphosphonic acid, and N,N-dimethyltaurine, were studied on the transport of Ca2+ by mitochondria isolated from rat liver. Taurine enhanced Ca2+ uptake in an apparently saturable process, with a Km value of about 2.63 mM. Taurine behaved as an uncompetitive activator of Ca2+ uptake, increasing both the apparent Km and Vmax values of the process. This effect was not modified in the presence of cyclosporin A (CsA). N,N-Dimethyltaurine also stimulated Ca2+ uptake at higher concentrations, but there was no evidence that the process was saturable over the concentration range used (1-10 mM). Aminoethylarsonate was a weak inhibitor of basal Ca2+ uptake, but inhibited that stimulated by taurine in an apparently competitive fashion (Ki = 0.05 mM). The other analogues had no significant effects on this process. Taurine either in the presence or the absence of CsA had no effect on Ca2+ release induced by 200 nM ruthenium red. Thus, the mechanism of taurine-enhanced Ca2+ accumulation appears to involve stimulation of Ca2+ uptake via the uniport system rather than inhibition of Ca2+ release via the ion (Na+/Ca2+ and/or H+/Ca2+) exchangers or by taurine modulating the permeability transition of the mitochondrial inner membrane. Overall, these findings indicate an interaction of taurine with an as yet unidentified mitochondrial site which might regulate the activity of the uniporter. The unique role of taurine in modulating mitochondrial Ca2+ homeostasis might be of particular importance under pathological conditions that are characterised by cell Ca2+ overload, such as ischaemia and oxidative stress.

Irradiation of amelanotic melanoma cells with 532 nm high peak power pulsed laser radiation in the presence of the photothermal sensitizer Cu(II)-hematoporphyrin: a new approach to cell photoinactivation

Cu(II)-hematoporphyrin (CuHp) was efficiently accumulated by B78H1 amelanotic melanoma cells upon incubation with porphyrin concentrations up to 52 microM. When the cells incubated for 18 h with 13 microM CuHp were irradiated with 532 nm light from a Q-switched Nd: YAG laser operated in a pulsed mode (10 ns pulses, 10 Hz) a significant decrease in cell survival was observed. The cell photoinactivation was not the consequence of a photodynamic process, as CuHp gave no detectable triplet signal upon laser flash photolysis excitation and no decrease in cell survival was observed upon continuous wave irradiation. Thus, it is likely that CuHp sensitization takes place by photothermal pathways. The efficiency of the photoprocess was modulated by different parameters; thus, while varying the amount of added CuHp in the 3.25-26 microM range had little effect, pulse energies larger than 50 mJ and irradiation times of at least 120 s were necessary to induce a cell inactivation of about 50%. The porphyrin-cell incubation time prior to irradiation had a major influence on cell survival, suggesting that the nature of the CuHp microenvironment can control the efficiency of photothermal sensitization.

Rectal temperature and prostaglandin E2 increase in cerebrospinal fluid of conscious rabbits after intracerebroventricular injection of hemoglobin

Fever accompanies subarachnoid hemorrhage (SAH) in the majority of patients. In a previous study, hemoglobin (Hb) was shown to catalyze in vitro, under aerobic conditions, the conversion of arachidonic acid to prostaglandin E2 (PGE2) and prostaglandin F2alpha. The aim of the present work was to assess whether this pathway also operates in vivo and to provide a mechanism to explain post-SAH fever. To this end, PGE2 concentration was determined in cerebrospinal fluid (CSF) of conscious rabbits chronically cannulated in the lateral ventricle and cisterna magna, following intracerebroventricular (i.c.v.) injection of 10 microg or 100 microg of commercial rabbit bicrystallized Hb as a model of SAH. Before i.c.v. injection, Hb solutions were filtered on a polimixin-B column to remove substantially, by over 90%, endotoxin-like substances. Results show that in nine rabbits injection of 10 microg Hb did not significantly modify body temperature or significantly alter CSF PGE2 content. On the contrary, in nine rabbits, injection of 100 microg Hb produced a significant increase in core temperature which was accompanied by a significant increase in CSF PGE2. When data related to these two parameters from the 9 control and 18 Hb-treated rabbits were analyzed as a single group, a linear, positive, and highly significant correlation was found. These findings indicate that, once Hb is released into the subarachnoid space during SAH, it enhances CSF PGE2 content and elicits hyperthermia, thus offering an explanation for the fever that is an aggravating condition in most SAH patients.

2,5-Di-t-butyl-1,4-benzohydroquinone induces endothelium-dependent relaxation of rat thoracic aorta

The aim of this work was to clarify the mechanism by which 2,5-di-t-butyl-1,4-benzohydroquinone (BHQ) induces relaxation of rat thoracic aorta. In particular, the role of endothelium-derived nitric oxide (NO) was investigated. BHQ concentration dependently (0.1-10 microM) relaxed rat aorta rings precontracted with phenylephrine. This effect was dependent on the intactness of the endothelium, suppressed by preincubation with 100 microM N(omega)-nitro-L-arginine methyl ester and antagonised by 3-30 microM methylene blue. The 10 microM BHQ-induced relaxation, however, was followed by the gradual and slow return to phenylephrine-induced tone. Superoxide dismutase (250 U/ml) increased the BHQ-induced relaxation, while preincubation with 3 mM diethyldithiocarbamate inhibited it in a time-dependent fashion. BHQ gave rise to superoxide anion formation which was markedly inhibited by the addition of superoxide dismutase (250 U/ml), either in the presence or in the absence of aorta rings. The non-specific blocker of Ca2+ channels, Ni2+, concentration dependently attenuated the BHQ relaxing effect. BHQ did not modify the relaxation induced by the NO donor 3-morpholino-sydnonimine in endothelium-deprived rings. In conclusion, BHQ induces endothelium-dependent relaxation and gives rise, by auto-oxidation, to the formation of superoxide anion. The former effect results from the enhanced synthesis of NO rather than from its enhanced biological activity; NO synthase is presumed to be stimulated by BHQ-induced activation of Ca2+ influx through Ni2+-sensitive Ca2+ channels.

Bilirubin photoisomerization products in serum and urine from a Crigler-Najjar type I patient treated by phototherapy

The relative compositions of the photoisomers of bilirubin-1X alpha (4Z, 15Z-bilirubin) in serum and urine of a patient with Crigler-Najjar type I syndrome treated by phototherapy are reported. High-performance liquid chromatography analysis reveals the presence of high serum levels of the configurational bilirubin photoisomer (4Z,15E-bilirubin) before the beginning of phototherapy (between 12 and 16% of the total bilirubin). The configurational photoisomer value increases during phototherapy with blue fluorescent lamps up to a photoequilibrium of about 25%, similar to that obtained in a bilirubin solution in vitro irradiated by the same lamps. This evidence suggests an inefficient serum excretion of the 4Z,15E-bilirubin. Indeed, its average half-life in serum of the Crigler-Najjar patient is found to be about 8 h. No detectable traces of the bilirubin structural isomer, lumirubin, are found in the serum. On the other hand, lumirubin represents the dominant bilirubin isomer excreted in the urine, as both 15Z and 15E configurations. Smaller amounts of 4Z,15E-bilirubin, 4E,15Z-bilirubin and native 4Z,15Z-bilirubin are observed in urine. The presence in urine of 4Z,15Z-bilirubin is probably due to a fast reversion of the configurational photoisomers to their native form. The half-life of the configurational photoisomers in urine kept at 38 degrees C is found to be of the order of a few minutes. Our study indicates that in Crigler-Najjar type I patients, mechanisms exist to excrete all bilirubin photoisomers. The lumirubin pathway seems to contribute markedly to bilirubin excretion in the urine, as occurs in jaundiced babies under phototherapy. However, the contribution of configurational isomers cannot be neglected.

Myorelaxant activity of 2-t-butyl-4-methoxyphenol (BHA) in guinea pig gastric fundus

This study investigates the mechanism whereby the antioxidant 2-t-butyl-4-methoxyphenol (BHA) relaxes guinea pig gastric fundus smooth muscle. In circular smooth muscle strips, 10 microM cyclopiazonic acid, a specific inhibitor of sarcoplasmic reticulum Ca2+-ATPase, induced a prolonged rise in tension which depended on the presence of extracellular Ca2+. BHA (pIC50 = 5.83), sodium nitroprusside (6.85), isoproterenol (7.69) and nifedipine (8.02), but not 2,6-di-t-butyl-4-methoxyphenol (DTBHA) (up to 30 microM), relaxed muscle strips contracted with cyclopiazonic acid. Methyl-1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)-pyri dine-5-carboxylate (Bay K 8644) (1 microM) antagonised the nifedipine- but not the BHA-induced relaxation. Nifedipine and isoproterenol (10 microM) caused a decrease in spontaneous tone, but did not counteract the subsequent rise in tension elicited by 10 microM cyclopiazonic acid. Conversely, 100 microM BHA and 100 microM sodium nitroprusside not only significantly reduced spontaneous tone but also markedly impaired the response of the muscles to cyclopiazonic acid. DTBHA failed to show either effect. When added to preparations completely relaxed by 100 microM BHA, 10 mM tetraethylammonium still elicited nifedipine-sensitive tonic and phasic contractions in the presence or absence of 10 microM cyclopiazonic acid. BHA and DTBHA inhibited, in a concentration-dependent manner, the Ca2+-promoted contraction of strips depolarised by 10 mM tetraethylammonium. The BHA antagonism showed a non-competitive profile while that of DTBHA was competitive. In muscle strips at rest, 10 microM BHA caused a significant increase in tissue cAMP concentration, leaving cGMP unmodified. To conclude, the myorelaxant action of BHA on gastric fundus smooth muscle appears to be mediated partly by an increase in cAMP levels and partly by inhibition of Ca2+ influx from the extracellular space.

Effects of 2,5-di-t-butyl-1,4-benzohydroquinone (BHQ) on rat aorta smooth muscle

To characterise the pharmacological activity of 2,5-di-t-butyl-1,4-benzohydroquinone (BHQ) on vascular smooth muscle, the different effects of BHQ on rat aorta were investigated under several experimental conditions. In aortic rings at rest or depolarised with 80 mM K+ in the presence of 1 microM nifedipine, BHQ evoked a slow tonic contraction which was antagonised by 1 mM Ni2+. Depolarised rings contracted in response to addition of 1 mM Ca2+, with an EC50 value of 32.4+/-1.0 mM for K+. At 20 mM K+, Ca2+-induced contraction was enhanced by BHQ. This effect was antagonised by 1 mM Ni2+, but not by 1 microM nifedipine. By contrast, at 40, 80 and 128 mM K+, BHQ antagonised Ca2+-induced contraction. This effect was partially reversed by 1 microM methyl-1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)-pyri dine-5-carboxylate (Bay K 8644) or by increasing extracellular Ca2+ concentration. In the presence of nifedipine and Ni2+, depolarised rings (80 mM K+) contracted in response to addition of 1 microM phenylephrine; this response was fast and then slowly decreased. When the preparations were preincubated with BHQ, the phenylephrine-induced contraction was transient and antagonised in a concentration-dependent manner by BHQ. These results indicate that the myotonic effect of BHQ on rat aortic rings depends on activation of Ca2+ influx via a Ni2+-sensitive pathway, whereas its myolytic activity is due either to antagonism of Ca2+ entry via L-type Ca2+ channels or depletion of intracellular Ca2+ stores.

Soluble intercellular adhesion molecule-1 in ovarian follicles: production by granulosa luteal cells and levels in follicular fluid

OBJECTIVE

To determine the concentration of the soluble form of intercellular adhesion molecule (ICAM)-1 in granulosa luteal cell-conditioned media and in follicular fluid (FF).

DESIGN

Granulosa cells and FF samples were obtained at the time of oocyte retrieval for IVF. In 10 women, a total of 33 fluids were obtained from individual follicles, whereas in 70 women, the follicular aspirates were pooled.

SETTING

Clinica "L. Mangiagalli" and Reproductive Center, San Raffaele Hospital, Milan, Italy.

PATIENT(S)

Eighty women referred for IVF for tubal factor or male factor infertility.

INTERVENTION(S)

Women underwent ovarian hyperstimulation.

MAIN OUTCOME MEASURE(S)

Soluble ICAM-1 was measured by an ELISA, and its levels were correlated with follicular size, the number of retrieved oocytes, and the number of follicles with a diameter of >15 mm.

RESULT(S)

The concentration of soluble ICAM-1 in granulosa luteal cell-conditioned media was 17.8 +/- 1.8 ng/5 x 10(5) cells. Interleukin-1beta can stimulate soluble ICAM-1 release in a dose-dependent manner. A significant positive correlation was demonstrated between levels of soluble ICAM-1 in pooled FF and the number of retrieved oocytes or the number of follicles with a diameter of >15 mm.

CONCLUSION(S)

Soluble ICAM-1 can be released by granulosa luteal cells and can be detected in FF after ovarian hyperstimulation. Levels of soluble ICAM-1 in FF correlate directly with some indices of ovarian function.

Fibreoptic phototherapy in the management of jaundice in low birthweight neonates

A fibreoptic phototherapy device has been compared with conventional white and special blue fluorescent phototherapy lamps to evaluate its efficacy in lowering serum bilirubin levels in low-birthweight neonates. Fibreoptic phototherapy was found to be as effective as white light and less effective than blue light, as assessed by (i) the bilirubin concentration after 24 h of phototherapy and at the end of phototherapy, (ii) the duration of phototherapy, (iii) the percentage daily decline rate and (iv) the overall percentage decline rate (p < 0.05). There were no failures of phototherapy and the need for re-exposure was low (4.7% of the total sample), with no difference between groups. The fibreoptic approach represents a promising way to aggregate synergically the most recent optical technologies and develop a modern, efficient and caring phototherapy system for low-birthweight infants.

Photophysics of the Variable Quantum Yield of Asymmetric Bilirubin

Bilirubin (BR), responsible for neonatal jaundice, is a 'Siamese twin' type of molecule containing two pyrromethenone chromophores conjoined by a saturated carbon CH2 group. Because neonatal jaundice is cured by phototheraphy, bilirubin has been extensively studied by laser means. When the chromophores in each half of the molecule are identical, we have symmetrical BR (SBR); when they are not, we have antisymmetric BR (ASBR). The quantum yield of the photoproducts from SBR is not wavelength-dependent, while that from ASBR is, in organic solvents. Because of the proximity of the two chromophores, both the ASBR and SBR systems are subject to Davidov (dynamic electric dipole) splitting of the chromophore excited states. A quantum mechanical calculation shows that when the two (asymmetric) chromophore states are not degenerate, the higher Davidov state is preferentially occupied by the chromophore with the 'original' higher energy, and the lower Davidov state by the chromophore of 'original' lower energy. This is just what is required for the quantum yield to vary with wavelength. If the variation of the quantum yield of asymmetric bilirubin in the presence of human serum albumin is approximated by a square-wave (narrow line approximation), a quantum mechanical calculation of the ratio of the short wavelength photoproduct yield with the long wavelength one is in agreement with accepted values for the 'original' energy difference of the chromophores, and the Davidov splitting parameter.