Electrophysiological and metabolic effects of CHF5074 in the hippocampus: protection against in vitro ischemia.

CHF5074 is a non-steroidal anti-inflammatory derivative holding disease-modifying potential for the treatment of Alzheimer's disease. The aim of the present study was to characterize the electrophysiological and metabolic profile of CHF5074 in the hippocampus. Electrophysiological recordings show that CHF5074 inhibits in a dose-dependent manner the current-evoked repetitive firing discharge in CA1 pyramidal neurons. This result is paralleled by a dose-dependent reduction of field excitatory post-synaptic potentials with no effect on the paired-pulse ratio. The effects of CHF5074 were not mediated by AMPA or NMDA receptors, since the inward currents induced by local applications of AMPA and NMDA remained constant in the presence of this compound. We also suggest a possible activity of CHF5074 on ASIC1a receptor since ASIC1a-mediated current, evoked by application of a pH 5.5 solution, is reduced by pretreatment with this compound. Moreover, we demonstrate that CHF5074 treatment is able to counteract in hippocampal slices the OGD-induced increase in alanine, lactate and acetate levels. Finally, CHF5074 significantly reduced the apoptosis in hippocampal neurons exposed to OGD, as revealed by cleaved-caspase-3 immunoreactivity and TUNEL staining. Overall, the present work identifies novel mechanisms for CHF5074 in reducing metabolic acidosis, rendering this compound potentially useful also in conditions of brain ischemia.

Pharmacological modulation of long-term potentiation in animal models of Alzheimer'’s disease.

The discovery of long-term potentiation (LTP) of hippocampal synaptic transmission, which represents a classical model for learning and memory at the cellular level, has stimulated over the past years substantial progress in the understanding of pathogenic mechanisms underlying cognitive disorders, such as Alzheimer’s disease (AD). Multiple lines of evidence indicate synaptic dysfunction not only as a core feature but also a leading cause of AD. Multiple pathways may play a significant role in the execution of synaptic dysfunction and neuronal death triggered by beta-amyloid (Abeta) in AD. Following intensive investigations into LTP in AD models, a variety of compounds have been found to rescue LTP impairment via numerous molecular mechanisms. Yet very few of these findings have been successfully translated into disease-modifying compounds in humans. This review recapitulates the emerging disease-modifying strategies utilized to modulate hippocampal synaptic plasticity with particular attention to approaches targeting ligand-gated ion channels, G-protein-coupled receptors (GPCRs), Receptor Tyrosine Kinases (RTKs) and epigenetic mechanisms. It is hoped that novel multi-targeted drugs capable of regulating spine plasticity might be effective to counteract the progression of AD and related cognitive syndromes.

Effectiveness of diagnosis and early treatment of ocular motility alterations in premature infants.

Objective: Prematurity often results in important developmental sequelae of brain structures, particularly those involved in processing visual information, such as the optic nerve, primary visual cortex and visuomotor integration areas. The aim of this study is to analyse the functionality of the sensory and motor pathways of the visual system by means of an orthoptic-ophthalmological assessment. Materials and methods: In this retrospective study, 151 records were examined, covering a period from 2000 to 2020, of preterm patients with gestational age < 32 weeks and birth weight ≤ 1,500 g up to an average age of about 8 years, referred to the Centre for Paediatric Ophthalmology and Strabology of the Ophthalmology Clinic of the Policlinico Umberto I, La Sapienza University of Rome, who underwent a complete ophthalmological and orthoptic assessment including the following tests measurement of ocular deviations according to the Hirschberg method, Lang I-II test, Titmus Stereotest, objective convergence assessment and ocular motility examination. Results: From the charts reviewed, 24.5% (37/151) of patients had Retinopathy of the Premature (ROP); while 38% of the whole sample (57/151) had strabismic amblyopia, of the latter only 31.5% (18/57) had ROP. In 8% of patients (12/151) the stereoscopic sense was absent, in 45% (8/151) stereopsis was gross (> 60 seconds of arc). In addition, 20.52 % (31/151) had a manifest eye deviation. 7.28% (11/151) had hypermetropia in the right eye (RE); 7.95% (12/151) hypermetropia in the left eye (OS); 3.31% of the patients (5/151) had myopia in the RE; 2% (3/151), myopia in the left eye (LE). In addition, the study of ocular motility revealed varying degrees of alteration poorly correlated with prematurity status. Conclusion: It was found that amblyopia, stereopsis and objective convergence are more affected by ROP than strabismus, refractive defects and ocular motility, indicating that premature children are particularly susceptible to ophthalmological and orthoptical alterations.

Precision management of pollination services to blueberry crops.

While the cultivated area of pollinator-dependent crops is increasing, pollinator availability is decreasing, leading to problems in many agroecosystems. For this reason, pollinator-dependent crop growers often rent beehives to support their pollination requirements to sustain fruit productivity. However, the efficiency of those pollination systems has not been extensively studied. Here, we compared the effect of "precision" pollination (i.e., application of pesticides coordinated with growers, audit of hives, dietary supplementation and individual distribution of hives) with conventional practices (i.e., pesticides applications without coordination with growers and no audit of hives, low maintenance of hives and hives distributed in large groups) on the mean level of pollination and fruit production and quality in blueberry crops. In nine blueberry fields, we measured bee visitation rate to flowers, fruit set, fruit firmness and fruit weight. On average, precision-pollinated plots had 70% more bee visits to flowers and produced 13% more fruits that were 12% heavier and 12% firmer than those obtained through conventional practices. These results showed that pollination efficiency could be improved if key management related to bee strength, distribution and health care are taken into account. Due to these results, we encourage growers and beekeepers to include precision pollination practices to both increase the productivity of blueberry fields and the wellbeing of honey bees within agroecosystems.

Infection prevention in endoscopy practice: comparative evaluation of re-usable vs single-use endoscopic valves.

Re-usable air/water and suction valves used in endoscopes often demonstrate risk of infection. To the authors' knowledge, the safety and efficacy of re-usable and single-use valves have not been compared to date. As such, a laboratory investigation was undertaken to compare the safety and efficacy of re-usable and single-use valves at 11 Italian endoscopy sites. Safety was evaluated by analysing the rinse liquid of reprocessed re-usable valves ready for use, and efficacy was assessed based on the completion of endoscopic procedures without valve malfunction. This study found significantly lower contamination of single-use valves compared with re-usable valves (0 vs 29.1%, respectively; P=0.007) and similar efficacy (97.6 vs 98.8%, respectively; P=ns). Microbiological analysis of the rinse liquid of reprocessed re-usable valves identified various surviving micro-organisms and highlighted their potential pathogenicity. Such data suggest that sterile single-use valves may be safer than re-usable valves, and have comparable performance.

Real-life efficacy and safety of Ustekinumab as second- or third-line therapy in Crohn's disease: results from a large Italian cohort study.

OBJECTIVE: Ustekinumab (UST) is an anti-IL12/23 antibody for the treatment of Crohn's Disease (CD). The aim of this study was to compare the efficacy and safety of UST in a large population-based cohort of CD patients who failed previous treatment with other biologics. PATIENTS AND METHODS: 194 CD patients (108 males and 86 females, mean age 48 years (range 38-58 years) were retrospectively reviewed. 147 patients were already treated with anti-TNFα (75.8%), and 47 (24.2%) patients were already treated with anti-TNFα and vedolizumab. Concomitant treatment with steroids was present in 177 (91.2%) patients. RESULTS: At week 12, clinical remission was achieved in 146 (75.2%) patients. After a mean follow-up of 6 months, clinical remission was maintained in 135 (69.6%) patients; at that time, mucosal healing was assessed in 62 (31.9%) patients, and it was achieved in 33 (53.2) patients. Three (1.5%) patients were submitted to surgery. Steroid-free remission was achieved in 115 (59.3%) patients. Both serum C-Reactive Protein and Fecal Calprotectin (FC) levels were significantly reduced with respect to baseline levels during follow-up. A logistic regression, UST therapy as third-line therapy (after both anti-TNFα and vedolizumab), FC >200 µg/g, and HBI ≥8 were significantly associated with lack of remission. Adverse events occurred in 5 (2.6%) patients, and four of them required suspension of treatment. CONCLUSIONS: UST seemed to be really effective and safe in CD patients unresponsive to other biologic treatments, especially when used as second-line treatment.

A unique V-J-C-rearranged gene encodes a gamma protein expressed on the majority of CD3+ T cell receptor-alpha/beta- circulating lymphocytes.

We have recently described an mAb, anti-Ti gamma A, that recognizes an antigenic determinant carried by a TCR gamma chain. This antibody binds to approximately 3% of human PBLs and delineates a CD2+, CD3+, TCR-alpha/beta-, CD4-, CD8+/-, CD5+, NKH1-, and HLA class II- subset. The present study was designed to identify the gene encoding the Ti gamma A epitope. A first analysis was carried out on a previously characterized TCR gamma + fetal-cloned cell line termed F6C7. It was found that F6C7 cells have one gamma rearrangement on each chromosome: one joins V gamma 3 to J gamma 1, and the second joins V gamma 9 to J gamma P. Because only the latter allele appeared to be transcribed in the F6C7 lymphocytes, these data strongly suggested that anti-Ti gamma A mAb is specific for either a V gamma 9 or a V gamma 9-J gamma P-encoded peptide. To confirm this point, we studied an additional series of 13 randomly selected Ti gamma A+ cloned cells derived from peripheral blood of three distinct adult individuals. Each one of these lymphocytes was shown to both possess and transcribe a V gamma 9-J gamma P-C gamma 1-rearranged gene. It is therefore concluded that a predominant subpopulation of CD3+ TCR-alpha/beta- human circulating T lymphocytes (namely, the subset defined by anti-Ti gamma A mAb) surface expresses a gamma protein with a limited potential of variability from one cell to another.

Natural killer clones derived from fetal (25 wk) blood. Probing the human T cell receptor with WT31 monoclonal antibody.

We have conducted a phenotypic and functional analysis of 19 cloned cell lines generated after allogeneic stimulation of circulating lymphocytes from a normal human fetus aged 25 wk. Using a limited series of mAbs (Anti-T3, WT31, T4, T8, and NKH1A), cloned cells were found to fall in three groups. Three clones have a conventional "inducer" phenotype. Three clones have a phenotype (T3+, WT31+, T8+, and NKH1A+) similar to that of certain NK active mature T lymphocytes present in adult peripheral blood. In contrast, 13 cell lines display surface characteristics that have not been described previously. Indeed, they express T3 proteins but not the WT31 determinant. In light of previous studies, these results show that WT31 mAb is a unique reagent directed at an invariant epitope of the human T cell receptor that is not present on all circulating T3+ fetal lymphocytes. Functionally the T3+, WT31+, and NKH1A+ clones were found to kill immunizing LAZ 388 cells, as well as K562, while T3+, WT31- and NKH1A+ clones display NK-like function exclusively. Moreover, only WT31+ lymphocytes present in the cell line used for cloning experiments have the capacity to recognize alloantigen-bearing cells. Together, these data suggest that expression of WT31 may be necessary for recognition of alloantigens, while NK reactions mediated by T3+ lymphocytes are WT31-independent.

Acute kidney injury in children after cardiac surgery: Risk factors and outcomes. A retrospective, cohort study. / Lesión renal aguda en niños poscirugía cardíaca: factores de riesgo e impacto evolutivo. Estudio de cohorte retrospectiva.

INTRODUCTION: Acute kidney injury (AKI) has been described as a common complication of cardiac surgery in pediatric patients, whose impact on morbidity and mortality has been documented. Its incidence has been estimated to be approximately 40 % in this patient group. The objective of this study was to estimate the incidence of AKI in patients who underwent cardiovascular surgery and to define associated risk factors and the impact of AKI on the parameters of the postoperative course. POPULATION AND METHODS: This was a retrospective, observational study of pediatric patients who underwent cardiovascular surgery between January 2015 and December 2017 at Hospital Británico de Buenos Aires. The incidence of AKI was defined as per the Kidney Disease: Improving Global Outcomes criteria, based on pre- and post-operative blood creatinine levels and urine output. RESULTS: A total of 125 patients were included. Of them, 35 % developed AKI. The analysis of risk factors showed a statistically significant difference for the administration of vancomycin and thiazide diuretics, red blood cell transfusion requirement, extracorporeal circulation pump time, clamp time, maximal intraoperative lactate level, minimum temperature, and delayed chest closure. In relation to the parameters of the post-operative course, we observed a longer hospital stay, higher inotropic requirement, more days of mechanical ventilation, bleeding, and neurological complications. CONCLUSION: In this study, the incidence of AKI was 35 %. Modifiable and non-modifiable associated risk factors were defined and a greater rate of complications was observed in patients who developed AKI.

Introducción. La lesión renal aguda (LRA) ha sido descrita como una complicación frecuente de las cirugías cardíacas en pacientes pediátricos, con impacto documentado en la morbimortalidad. Se estima una incidencia de alrededor del 40 % en este grupo de pacientes. El objetivo del trabajo fue calcular la incidencia de LRA en pacientes que tuvieron cirugía cardiovascular, definir los factores de riesgo asociados y el impacto de la LRA en los parámetros de evolución posquirúrgica. Población y métodos: Se realizó un estudio retrospectivo observacional sobre pacientes pediátricos con cirugías cardiovasculares, operados entre enero de 2015 y diciembre de 2017 en el Hospital Británico de Buenos Aires. Se definió la incidencia de LRA según los criterios de Kidney Disease: Improving Global Outcomes, considerando los valores de creatininemia y ritmo diurético pre- y posquirúrgicos. Resultados. Se incluyeron un total de 125 pacientes. Un 35 % desarrolló LRA. Al analizar los factores de riesgo, se observó una diferencia estadísticamente significativa para administración de vancomicina, diuréticos tiazídicos, requerimiento transfusional de glóbulos rojos, tiempo de bomba de circulación extracorpórea, de clampeo, lactato máximo intraquirúrgico, temperatura mínima y cierre diferido del tórax. Entre los parámetros de evolución posquirúrgica, se observó un incremento en la duración de la internación, requerimiento de inotrópicos, días de asistencia respiratoria mecánica, sangrado y complicaciones neurológicas. Conclusión. La incidencia de LRA en este estudio fue del 35 %. Se pudieron definir factores de riesgo modificables y no modificables asociados, y se detectó una mayor incidencia de complicaciones en aquellos pacientes que desarrollaron LRA.

Oral glucose tolerance test unravels circulating miRNAs associated with insulin resistance in obese preschoolers.

BACKGROUND: Circulating microRNAs (miRNAs) may act as biomarkers of metabolic disturbances. OBJECTIVE: The aim of this study was to identify serum miRNAs signature of early insulin resistance in obese preschoolers. METHODS: Twelve obese children, aged 2-6 years, six insulin resistant (IR) and six controls were selected being age-matched, sex-matched and body mass index-matched. Profiling of 179 circulating miRNAs, known to be widely expressed in the bloodstream, was investigated by quantitative polymerase chain reaction at fasting and 120 min following a standard oral glucose tolerance test (OGTT). RESULTS: Twenty-one miRNAs were differentially regulated in IR obese preschoolers. miR-200c-3p, miR-190a and miR-95 were differently regulated both at fasting and 120 min after the OGTT. In controls, the fold changes of some miRNAs were correlated with Δglucose0-120 (miR-660, miR-26b-5p and miR-22-3p: p = 0.005 for all) and Δinsulin0-120 (miR-660 and miR-22-3p: p = 0.02 for both and miR-423-5p: p = 0.042). In IR patients, miR-1 fold changes were correlated with Δglucose0-120( r = -0.786; p = 0.036) and Δinsulin0-120( r = -0.821; p = 0.023). CONCLUSIONS: Our study identifies circulating miR-200c-3p, miR-190a and miR-95 as biomarkers of insulin resistance in obese preschoolers, being differentially regulated in IR patients both in fasting condition and after the OGTT. Expression of some circulating miRNAs seems reflecting glucose and insulin excursion following the OGTT differently in controls and IR obese preschoolers.

Carpal tunnel syndrome and ulnar neuropathy at the elbow in floor cleaners.

OBJECTIVE: To determine the occurrence of carpal tunnel syndrome (CTS) and ulnar neuropathy at the elbow (UNE) in a cohort of floor cleaners and to check differences between workers with and without CTS. METHODS: All female floor cleaners of three major hospitals in Tuscany (Italy) were contacted. Clinical and electrophysiological severity of CTS and UNE were evaluated with standardized scales and symptoms were assessed with the self-administered Boston Questionnaire (BQ); demographic and non-occupational factors and durations of current and previous occupations were recorded. Univariate analysis of risk factors was performed in workers with and without CTS. Logistic regression was used to evaluate the capacity of independent variables to predict CTS. RESULTS: Out of a total of 179 cleaners, 145 (81%)-mean age 39.6 years (20-64 years)-were enrolled in the study; 70 (48%) had CTS (diagnosis based on clinical and electrophysiological findings). BQ symptom and hand function scores were anomalous in 108 (74%) and 84 (58%) subjects, respectively. UNE was detected in 7/103 women. Univariate analysis showed that cleaners with CTS were older, had greater BMI and longer exposure to cleaning with previous employers than those without CTS. In the logistic regression, the only predictor of CTS was cleaning with previous employers (O.R. 12.1, 95% CI 3-49.9). CONCLUSIONS: These results indicate a high occurrence of CTS in floor cleaners; UNE is less frequent than CTS, presumably due to repetitive movements that stress wrists more than elbows. The only predictive factor of CTS was cleaning as an occupation with previous employers. Therefore, the actual risk factor for CTS could not be cleaning per se, but how this job is performed.

[CT and MR virtual colonscopy: indications, limits and comparison with conventional colonscopy]. / Colonscopia virtuale TC e RM: indicazioni, limiti e confronto con la colonscopia tradizionale.

Virtual endoscopy is a new method for studying the colon; it consists in acquisition of CT and MR images and to elaborate them with a workstation, to create endoluminal vision as like as traditional colonscopy, permitting the complete exploration of colonic lumen, also with stenotic tumors. The analysis of the differences between CT and MR colography shows like these two techniques present both advantages and disadvantages, such as the impossibility to perform MR in patients with pace-maker or in claustrophobic patients and the impossibility to perform CT with iodated agents in patients with renal failure or with a story of adverse reactions. The increased use of these techniques is due to the high sensitivity of last-generation CT and MR machine, to the increased spatial resolution, to specific softwares for digital cleaning of colon, to the introduction of high-end workstations and to the possibility of computed assisted diagnosis (CAD). So, it is desiderable that the increasing spread of multidetector CT devices and the future technical innovations, should have the effect to increase culture and experience in various diagnostic centers about CT-colography, making possible the spreading of virtual endoscopy as a screening tool.

Failure of aldosterone suppression despite angiotensin-converting enzyme (ACE) inhibitor administration in chronic heart failure is associated with ACE DD genotype.

OBJECTIVES: The objective of this study was to assess whether the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism influences the adequacy of the neurohormonal response to ACE inhibitors in patients with chronic heart failure (CHF). BACKGROUND: The renin-angiotensin-aldosterone system (RAAS) plays an important role in the pathophysiology of CHF, and aldosterone levels closely relate to outcome in patients with CHF. Angiotensin-converting enzyme inhibitors suppress the RAAS, but a significant proportion of patients exhibit elevated serum levels of aldosterone despite long-term administration of apparently adequate doses of these agents. METHODS: We prospectively studied 132 patients with CHF (ejection fraction <45%) receiving long-term therapy with ACE inhibitors for over six months. Patients taking aldosterone antagonists were excluded from the study. "Aldosterone escape" was defined as being present when plasma aldosterone levels were above the normal range in our laboratory (>42 nmol/L). Patients were then divided into two subgroups according to the presence (group 1) or absence (group 2) of aldosterone escape. Genotype analysis for the ACE I/D polymorphism was performed by polymerase chain reaction. RESULTS: The prevalence of aldosterone escape in our patients was 10% (13/132). The two groups of patients did not differ regarding the dose of ACE inhibitor, diuretics and their renal function. There was a statistically significant different distribution of genotypes between the two groups, with a higher proportion of DD genotype in group 1 compared with group 2 (62% vs. 24%, p = 0.005). CONCLUSIONS: Patients with CHF with aldosterone escape have a higher prevalence of DD genotype compared with patients with aldosterone within the normal limits. Angiotensin-converting enzyme gene polymorphism contributes to the modulation and adequacy of the neurohormonal response to long-term ACE-inhibitor administration in CHF.

Serum retinol levels throughout 2 years of cholesterol-lowering therapy.

Some studies have reported an inverse correlation between serum cholesterol level and risk of cancer. This correlation might be due to a decrease in serum retinol, a lipid-soluble vitamin that controls cell proliferation and differentiation. We evaluated the influence of cholesterol-lowering therapy on serum retinol in 102 subjects (mean +/- SE: aged 47.1 +/- 4.1 years; body mass index, 23.8 +/- 0.6 kg/m2) with primary hypercholesterolemia treated for 2 years with different therapeutic protocols. Twenty-two subjects had been treated with diet alone, 35 with diet and fibrates, 37 with diet and hepatic hydroxymethyl glutaryl coenzyme A (HMG CoA) reductase inhibitors (statins), and eight with diet and cholestyramine. Postabsorptive serum retinol, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglyceride levels were determined at baseline and every 3 months. Baseline TC and LDL-C were significantly lower in the diet-treated group than in other groups. No intergroup differences were found in pretreatment levels of triglycerides and serum retinol. After 2 years of treatment, TC and LDL-C serum levels were not significantly decreased in the diet-alone group, whereas they were decreased by 20% and 24%, respectively, in the gemfibrozil group, 28% and 34% in the statins group; and 21% and 27% in the cholestyramine group. In the entire population (N = 102), serum retinol was 3.46 +/- 0.08 mumol/L before therapy and 3.76 +/- 0.07 after 2 years of therapy (P < .001). Serum retinol increased in diet- and statin-treated groups, but not in fibrate- and resin-treated groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Procedure for effective separation of high-density lipoproteins in normal serum and hypertriglyceridemic samples.

A chemical procedure for high-density lipoprotein (HDL) separation in normo- and hyperlipidemic sera has been developed. The procedure is effective up to 25 mmol/L of serum triglycerides and the constituents of the precipitation mixture (dextran sulfate, PEG-6000 and MgCl2) do not interfere with enzymatic assay of the HDL cholesterol.

Effect of nimodipine on drinking behavior measured in the runway: comparison and interaction with (+/-)-amphetamine.

The aim of the present study was to evaluate the ability of the calcium channel blocker (CCE), nimodipine (NIM), to interact with (+/-)-amphetamine (AMPH) in modifying ingestive behavior. Rats performed in a water-reinforced runway paradigm with multiple trials. Water was available in sufficient quantity to produce satiety under control conditions as measured by a decline in response rate over the session. NIM and AMPH, given alone, did not produce significant effects on performance but produced behavioral changes when administered in combination. In particular, the combination of the highest doses (13 mg/kg i.p. NIM plus 0.56 mg/kg i.p. AMPH) initially depressed both running and drinking, whereas in later trials it increased running rate, without producing a parallel increase in water intake. These results suggest that NIM enhances AMPH-produced inhibition of drinking, whereas it first depresses and then enhances the AMPH-mediated runway performance, suggesting the rate dependency of this latter effect.

Cocaine toxic effect on endothelium-dependent vasorelaxation: an in vitro study on rabbit aorta.

Effects of cocaine on vascular endothelium relaxing properties and the related mechanism were investigated in vitro in rabbit aorta. Several vasorelaxing agents with different mechanisms, i.e. acetylcholine, substance P, calcium ionophore A23187, 2,5-di-tert-butylhydroquinone, or sodium nitroprusside, were employed. Cocaine effects on the vascular response to relaxing agents in cumulative (acetylcholine, substance P, or A23187) or single dose (2,5-di-tert-butyl-hydroquinone) were performed in endothelium-intact aortic rings precontracted with phenylephrine. Relaxing activity of cumulative doses of sodium nitroprusside was evaluated in endothelium-denuded aortic rings, in the presence of cocaine. Cocaine significantly reduced endothelium-dependent relaxations induced by acetylcholine, or substance P. By contrast A23187 endothelium-mediated relaxation as well as endothelium-independent relaxation by sodium nitroprusside were unaffected by cocaine. Furthermore, cocaine significantly increased endothelium-dependent relaxation response to 2,5-di-tert-butylhydroquinone, a sarcoplasmic Ca2+-ATPase pump inhibitor, in the aortic rings. These findings indicate that cocaine reduces nitric oxide release from vascular endothelium apparently through the inhibiting action of Ca2+-ATPase pump.

Analysis of point mutations in HPRT mutant T-lymphocytes derived from coke-oven workers.

We studied mutations in exon 3 of the hypoxanthine-guanine phosphoribosyltransferase (HPRT) locus in 113 6-thioguanine-resistant T-cell clones derived from coke-oven workers and control subjects in order to analyse possible changes in the mutational spectrum associated with the exposure to polycyclic aromatic hydrocarbons (PAHs). In 99 mutants, HPRT exon 3 was analysed by means of genomic polymerase chain reaction (PCR) and single-strand conformation polymorphism (SSCP). Products for which SSCP indicated the presence of a mutation were further analysed by DNA sequencing. In addition, HPRT cDNA from 14 clones was analysed by reverse transcription (RT) PCR and DNA sequencing. In total, 18/113 mutants (16%) had a mutation in exon 3. This frequency was similar in PAH-exposed (9/57) and non-exposed (9/56) subjects. Base substitutions caused 14 mutations at 13 different sites. Three +/- 1 bp frameshifts and one 6 bp deletion were identified. No significant differences between PAH-exposed and non-exposed workers were observed in this limited mutational spectrum. These results indicate that deletions/insertions at the HPRT exon 3 account for 22% of the mutations, and base substitutions for 78%.

Opiatergic modulation of preparatory and consummatory components of feeding and drinking.

We present data here indicating that stimulation of kappa but not mu opiate receptors influences motivational and consummatory aspects of feeding and drinking. To differentiate mu and kappa mechanisms controlling preparatory (appetitive) and consummatory components of ingestive behavior, the effects of morphine (MORPH), compound U50488H (U50) and naloxone (NAL) were studied in rats trained to negotiate a straight runway using food or water as a reinforcer. At doses that increase feeding and drinking in conditions of free access to food and water (i.e., 1-2 mg/kg IP), MORPH affected neither food- nor water-maintained runway performance. Since 1 mg/kg of NAL is also devoid of effects, mu-opiate mechanisms are probably not involved in food- or water-maintained behavior. Pharmacological manipulation of kappa-opiate mechanisms had complex effects. At 5 mg/kg, NAL accelerated satiation, depressing food intake, without affecting running. U50 did not increase food intake, but accelerated running for food, an effect that was antagonized by a high dose of NAL (5 mg/kg). These findings suggest that motivational and consummatory components of food-maintained runway performance are both activated by kappa-opiate mechanisms. NAL also reduced water intake but had minimal influences on running. In contrast, U50 depressed both water intake and runway performance; rather than being antagonized, these effects were slightly enhanced by NAL. The combined antidipsic and diuretic effects of U50 suggest that kappa-opiate mechanisms play a dissipatory role in water balance. However, the similar antidipsic effects of U50 and NAL, and the fact that NAL did not antagonize the antidipsic effects of U50, suggest that U50 may reduce drinking by mechanisms other than kappa-opiate agonism.

Dapiprazol prevents U50,488H-mediated suppression of preparatory components of drinking behavior in rats.

In a previous study, we found that the kappa opioid agonist U50,488H (U50) suppresses both appetitive and consummatory components of drinking behavior in rats trained to negotiate water in a straight runway. U50 also activates diuresis. Kappa opioid mechanisms could therefore play a dissipative role in the body's water balance. Since naloxone inhibits diuresis, but not hypodipsia produced by U50, these effects are probably mediated also by nonopioid mechanisms. In rats trained to negotiate water in a straight runway, we have studied the influence on the hypodipsic effects of U50 of the selective alpha-1 adrenoceptor antagonist dapiprazol (DAP), which we found to inhibit U50-mediated diuresis. When given alone, DAP (3 and 6 mg/kg IP) influenced neither running for water nor water intake; neither did it prevent the suppression of water intake produced by U50 (8 mg/kg IP) across the test. However, it did antagonize the U50-mediated slowing of running for water. Alpha-1 adrenoceptors thus appear to play a role in U50's effects on diuresis and the appetitive, but not consummatory, aspects of drinking.