Biomedical subjects

F Chiarotti

Publications and source records attributed to F Chiarotti.

At least 37 records · Page 2Linked to original sources

PubMed1995

CD4 Lymphocyte enumeration: comparison between flow cytometry and enzyme immunoassay.

Assessment of the CD4 lymphocyte number, currently performed by flow cytometry, is one of the main laboratory tests for establishing progression to acquired immunodeficiency syndrome (AIDS). An enzyme immunoassay has recently been commercialized which can be very useful for counting CD4 cells in laboratories where flow cytometers are not available. In the present study, a comparative evaluation of CD4 positive lymphocytes with flow cytometry and the enzyme assay was made in healthy subjects (N = 30, R = 0.88, P < 0.0001), human immunodeficiency virus (HIV)-infected individuals (N = 80, R = 0.91, P < 0.0001), and patients with autoimmune diseases (N = 28, R = 0.82, P < 0.001) or psoriasis (N = 18, R = 0.76, P = 0.01). A correlation between the two methodologies was not found in psoriatic patients under treatment with cyclosporin A (N = 7, R = 0.05, not significant). Some differences could be found at low CD4 lymphocyte levels since the influence of CD4 antigen eluted from monocytes or soluble CD4 in the whole blood sample could cause overestimation of CD4 cell numbers by the enzyme assay.

Acquired Immunodeficiency Syndrome↗

PubMed1995

Limited changes of mouse maternal care after prenatal oxazepam: dissociation from pup-related stimulus perception.

There is evidence that activity at the GABA/benzodiazepine receptor complex in specific brain areas might be enhanced during rodent motherhood. We tested the hypothesis that the manipulation of this neurochemical system by prenatal benzodiazepine exposure affects typical behavioral responses of lactating mouse dams. Outbred CD-1 mouse fetuses were administered either oxazepam (OX, 15 mg/kg) or vehicle twice a day on embryonic days 12-16 and fostered at birth to untreated dams. Female offspring were subsequently mated at the young adult stage. In a first experiment, the behavioural repertoire of the two groups of lactating females was scored (single 10-min session) from postpartum days 3 to 18. When compared with VEH dams, OX females showed a shorter duration of pup-sniffing at 7-10 days and enhanced crouching behaviour when pups had reached the age of 14-18 days. In addition, OX-treated dams used more cotton for nest construction than the controls. The two female groups were differentiated only in the presence of their offspring. In a second experiment aimed at investigating possible OX-induced changes in pup-stimulus perception, the same lactating females were challenged in sequence on postpartum day 8 with three different patterns of pup-related cues consisting of: three 8-day-old live male pups (LP), three same-age dead pups DP, or three dead pups accompanied by pre-recorded ultrasounds (DPU). In the absence of carry-over effects of prenatal dam treatment, LP stimuli elicited a higher frequency of sniffing and digging than the others, whereas the level of licking, and grooming was reduced. In conclusion, the present results indicate that the slight alteration in maternal care resulting from prenatal OX treatment can be dissociated from changes in pup-related stimulus perception.

Animals↗

PubMed1995

Risk factors of incomplete distribution of cardioplegic solution during coronary artery grafting.

Myocardial distribution of cardioplegic solution infused by combined antegrade/retrograde routes was assessed with myocardial contrast echocardiography in 18 patients with chronic stable angina and three-vessel disease undergoing elective coronary artery bypass grafting. Overall myocardial opacification was significantly greater in retrograde than in antegrade cardioplegia (77.7% +/- 13.4% versus 59.1% +/- 15.7%; p = 0.0009). The difference was affected by collateral circulation, as pointed out by the significant interaction between coronary collateral circulation and percent of myocardial opacification after antegrade and retrograde cardioplegia (p = 0.002). When we performed multiple comparisons, in patients with good collaterals the opacification difference between antegrade and retrograde cardioplegia was not statistically significant (66.4% +/- 10.2% versus 76.0% +/- 15.2%; p = not significant), whereas in patients with poor collaterals myocardial opacification during retrograde cardioplegia was significantly greater (44.3% +/- 15.0% versus 81.2% +/- 9.0%; p < 0.02). During antegrade cardioplegia, patients with poor collaterals showed a lower degree of myocardial opacification than patients with good collaterals (44.3% +/- 15.0% versus 66.4% +/- 10.2%; p < 0.01). Our results show that retrograde cardioplegia in patients undergoing elective coronary artery bypass grafting offers no advantage over antegrade cardioplegia when collateral circulation is well developed. On the other hand, conventional aortic root infusion may not provide adequate myocardial protection in the subset of patients with significantly narrowed or occluded coronary arteries and poor collaterals.

Angina Pectoris↗

PubMed1995

Results of surgical treatment of stage IIIA non-small cell lung cancer.

From 1975 to 1993, 665 patients with non-small cell lung carcinoma (NSCLC) were studied in our Unit. Of the 55 stage IIIA patients submitted to resection, 50 were followed-up in order to evaluate the effectiveness of surgery and to identify which variables had a prognostic impact on survival. The expectancy of survival at 3,5 and 10 years was 31.7, 19.5 and 13.7%, respectively. When the analysis was limited to N2 patients, 3,5- and 10-year survival rates were 20.9, 14 and 7%, respectively. Regarding the "TN" factor, the T3N0 subset presented the highest expected survival (24.8 and 18.6% at 5 and 10 years). With regard to the "T3" factor and type of surgery, peripheral tumors submitted to en bloc resection of the chest wall showed the best 5-year survival rate (42.9%), whereas extrapleural resections--even for tumors confined to the parietal pleura--showed a 5-year survival rate of 14.3%. A slightly higher risk of death was observed in tumors originating in the superior sulcus (SST). No patients with mediastinal pleura and pericardium involvement survived more than 34 months. With univariate analysis, "N2" was the variable most significantly associated with a negative prognosis when related to T3 (T3N2 vs T3N0 0.025 < P < 0.05) or non-epidermoid tumor (no survivors at 3 years; N2 epidermoid vs N2 non-epidermoid tumor P < 0.05). Applying multivariate analysis, epidermoid cell type, even if exclusively for N2 tumors, was an independent prognostic factor, showing a favorable impact on survival expectancy (27.8% at 90 months).

Adult↗

PubMed1995

Survival after AIDS among Italian haemophiliacs with HIV infection. The Italian Group on Congenital Coagulopathies.

OBJECTIVES: To estimate survival trends for persons with haemophilia and HIV/AIDS. DESIGN AND METHODS: Survival analysis conducted among the cohort of HIV-positive haemophiliacs with AIDS at the Italian Haemophilia Registry. Kaplan-Meier method was used to estimate survival times, stratifying for demographic and clinical covariates. Cox proportional hazards model was applied in order to identify factors independently associated with survival. RESULTS: Median survival from the first AIDS diagnosis to death was estimated to be 17.0 months for 176 individuals with AIDS. Median survival after AIDS diagnosis increased from 12.0 months in December 1983-December 1988 to 17.0 months in January 1989-May 1990 and to 25.0 months in June 1990-December 1991. Median survival times were significantly (P < 0.001) lower for individuals diagnosed with non-infective AIDS indicator diseases (lymphoma, AIDS-associated neurological disease, Kaposi's sarcoma, wasting syndrome: 4.0 months), in comparison with haemophiliacs diagnosed with Pneumocystis carinii pneumonia (PCP; 18.0 months) or other infections (35.0 months). Antiretroviral treatment after AIDS diagnosis was associated with a longer survival than that estimated for individuals with no treatment after AIDS; the same was true for PCP prophylaxis. Younger age at HIV seroconversion and at AIDS diagnosis were associated with a longer survival. Multivariate analysis showed that factors independently associated with survival were type of AIDS indicator disease and antiretroviral administration after AIDS diagnosis. CONCLUSIONS: This study indicates an increasing survival from AIDS diagnosis to death over time, also as a result of the introduction of antiretroviral therapy. Survival trends are similar to those reported among homosexual men and intravenous drug users with AIDS, suggesting a similar access to the health-care system for individuals with AIDS. Survival studies may improve our understanding of the natural history of HIV infection and may indicate the impact of preventive measures.

Acquired Immunodeficiency Syndrome↗

PubMed1994

Median time from seroconversion to AIDS in Italian HIV-positive haemophiliacs: different parametric estimates.

The purpose of this study was to estimate the median incubation time between human immunodeficiency virus (HIV) infection and onset of acquired immunodeficiency syndrome (AIDS), using three parametric models and six estimates of seroconversion time. Study subjects were 732 HIV-positive haemophiliacs enrolled in the Italian Registry of patients with congenital coagulation disorders. Seroconversion time was estimated for each subject according to six different criteria, based on three distributions of seroconversion (uniform, uniform on three sub-intervals and truncated Weibull) and two indices synthesizing each distribution (median and median of three random values). The estimated seroconversion times were subsequently used as starting points in the analysis of incubation. This was performed applying Kaplan-Meier non-parametric survival analysis, and fitting to incubation data three probability density functions, representing three different situations with respect to the hazard of developing AIDS following seroconversion (namely Weibull (WE), generalized exponential (GE) and log-logistic (LL)). The cumulative incidence over an 8-year period ranged from 14.9 to 17.8 per cent when applying the Kaplan-Meier method, from 14.1 to 17.2 per cent when using the WE function, from 14.5 to 17.3 per cent when using the GE function and from 14.4 to 17.3 per cent when using the LL function, depending on the estimate of seroconversion time used. Similarly, the median incubation times ranged from 12.6 to 15.0 years with the WE function, from 14.0 to 16.5 years with the GE function, and from 13.4 to 16.1 years with the LL function. The presence of a bound on the increase of the hazard function seems to affect the incubation more strongly than the eventual decrease following the attainment of the maximum risk. This may be due to the decrease in the hazard beginning when most of the seropositive subjects have already developed AIDS.

Acquired Immunodeficiency Syndrome↗

PubMed1994

Epidemiology of hemophilia and of HIV infection in Italy. GICC. Gruppo Italiano Coagulopatie Congenite.

To evaluate the incidence and prevalence of hemophilia in Italy and the impact of HIV infection on the Italian hemophiliac population, data from a computerized national registry of patients from 95% of the hemophilia care centers in Italy were analyzed. A total of 4643 patients were included in the registry. The prevalence of hemophilia A was 8.2 per 100,000 males, with no significant regional differences; for hemophilia B the corresponding figure was 1.5 per 100,000. Temporal trends in hemophilia incidence suggest that the diagnosis of mild and moderate hemophilia has improved. The overall HIV prevalence was 26% and was significantly (p < 0.001) higher in patients with hemophilia B (47.1%) compared to those with hemophilia A (26.8%) or other diseases (16.5%). The highest rate of HIV seropositivity was among patients 20-29 years of age. The annual amount of clotting factor concentrates received was significantly (p < 0.001) higher in HIV seropositive patients than in those who were seronegative. Antibody testing was never performed on 10.1% of severely affected patients. The number of patients in the Italian registry was similar to the number that would have been expected based on prevalence estimates from other countries. In comparison with other countries, the prevalence of HIV infection recorded in Italy was lower in persons with hemophilia A, but higher in those with hemophilia B. Our study demonstrates the usefulness of a registry in delineating the epidemiology of hemophilia and in studying risk factors for HIV infection. It also underlines the need for continuing surveillance of this population.

Adult↗

PubMed1994

d-amphetamine conditioned place preference in developing mice: relations with changes in activity and stereotypies.

Conditioned place preference (CPP) with both visual and tactile cues, hyperactivity, and stereotypies produced by d-amphetamine (1-10 mg/kg ip, single dose) were studied in CD-1 mice at 2, 3, and 4 weeks from birth. CPP was shown from the youngest age onward in female mice and from 3 weeks in male mice. Hyperactivity was much more pronounced in postweanlings (3 and 4 weeks) than in preweanlings. Stereotypies (at 3.3 and 10 mg/kg) occurred from the youngest age and tended to peak at 3 weeks. Stereotypies may indicate a sickness experience or "poor welfare" (G.J. Mason, 1991; A. Wall, R.E. Hinson, E. Schmidt, C. Johnston, & A. Streather, 1990) due to an aversive component of amphetamine's action. Therefore, the delayed development of fully fledged amphetamine CPP, relative to cocaine CPP (G. Laviola, G. Dell'Omo, E. Alleva, & G. Bignami, 1992), may be due to an age-dependent diminution of the positive hedonic value of the former drug by negative effects that are minimal or absent in the case of the latter drug.

Age Factors↗

PubMed1994

Sexual behaviour of gay and bisexual men in eight European countries.

To compare the sexual behaviour and HIV risk reduction strategies of gay and bisexual men in Europe, a survey, disseminated via the gay press and gay associations, was conducted amongst gay and bisexual men in Austria, Switzerland, Germany, Denmark, France, Great Britain, Italy and the Netherlands during the autumn and winter of 1991. By end March of 1992, 12,347 completed questionnaires had been obtained. A preliminary analysis shows striking similarities in patterns of sexual behaviour of gay men in the 8 European countries but indicates that strategies of risk management concerning HIV and AIDS vary widely. While the majority of gay men have multiple partners, and intercourse is more common with stable partners than with causal partners. The proportion of men who, during the past 12 months, engaged in unprotected anal intercourse with a partner with different or unknown HIV-status ranged from 1/3 in East Germany to 1/6 in UK. However, reported incidence over the past 12 months of STDs, other than HIV infection, was similar in all countries (2%-3%). The reported HIV antibody prevalence varied from less than 7% in East Germany, Italy and the United Kingdom to 15% in Denmark and 17% in France. HIV risk reduction strategies appear to be most common in those countries where the gay community had been included in targeted prevention campaigns during the early phase of the AIDS epidemic. Considering the high proportion of gay men engaging in high risk activities it is imperative that prevention efforts are sustained and improved.

Acquired Immunodeficiency Syndrome↗

PubMed1994

Clinical factors associated with progression to AIDS in the Italian cohort of HIV-positive hemophiliacs. G.I.C.C. Gruppo Italiano Coagulopatie Congenite.

This study updates estimates of the cumulative incidence of AIDS among Italian patients with congenital coagulation disorders (mostly hemophiliacs), and elucidates the role of age at seroconversion, type and amount of replacement therapy, and HBV co-infection in progression. Information was collected both retrospectively and prospectively on 767 HIV-1 positive patients enrolled in the on-going national registry of patients with congenital coagulation disorders. The seroconversion date was estimated as the median point of each patient's seroconversion interval, under a Weibull distribution applied to the overall interval. The independence of factors associated to faster progression was assessed by multivariate analysis. The cumulative incidence of AIDS was estimated using the Kaplan-Meier survival analysis at 17.0% (95% CI = 14.1-19.9%) over an 8-year period for Italian hemophiliacs. Patients with age greater than or equal to 35 years exhibited the highest cumulative incidence of AIDS over the same time period, 32.5% (95% CI = 22.2-42.8%). Factor IX recipients (i.e. severe B hemophiliacs) had higher cumulative incidence of AIDS (23.3% vs 14.2%, p = 0.01) than factor VIII recipients (i.e. severe A hemophiliacs), as did severe A hemophiliacs on less-than-20,000 IU/yearly of plasma-derived clotting factor concentrates, as opposed to A hemophiliacs using an average of more than 20,000 IU (18.8% vs 10.9%, p = 0.02). No statistically significant difference in progression was observed between HBsAg-positive vs HBsAg-negative hemophiliacs (10.5% vs 16.4%, p = 0.10). Virological, immunological or both reasons can account for such findings, and should be investigated from the laboratory standpoint.

Acquired Immunodeficiency Syndrome↗

PubMed1993

Familiarity with conspecific odor and isolation-induced aggressive behavior in male mice (Mus domesticus).

Male Swiss CD-1 mice (Mus domesticus, n = 60) were isolated for 24 days. In the isolation group mice were exposed to their own odor; in the familiarity group mice were familiarized with pairmates' odor by daily exchange of bedding; and in the unfamiliarity group subjects (exposed) were familiarized with pairmates' odor, whereas the pairmates (nonexposed) were familiarized with odors of other isolated mice. Aggressive behavior was scored during 20-min sessions. Familiarity with the pairmate's odor (familiarity and exposed subgroups) caused an enhancement of aggressive behavior, shown by the highest frequency of tail rattling and offensive upright posture and by a decrease in latency to the 1st attack. Nonexposed subjects showed high values of submissive upright posture, screaming, fleeing, and freezing. The results suggest that dominantlike behavior, acquired in social isolation, may be directed toward a conspecific whose odor is familiar.

Aggression↗

PubMed1993

Mechanisms of incomplete cardioplegia distribution during coronary artery surgery. An intraoperative transesophageal contrast echocardiography study.

BACKGROUND: Cardioplegia is used to protect the myocardium from ischemic injury during open-heart surgery. However, the delivery of cardioplegic solutions may be impaired by anatomic and/or functional conditions, such as the development of transient aortic regurgitation during antegrade administration of cardioplegia or shunting through a foramen ovale during retrograde administration. In this study, the authors used a new method of cardioplegia administration, based on intraoperative contrast echocardiography, to detect on-line causes of inadequate cardioplegia delivery. METHODS: Forty patients with coronary artery disease and a competent aortic valve, who were treated consecutively, were enrolled in this study. Patients were monitored intraoperatively by transesophageal contrast echocardiography during cardioplegia delivery. Antegrade cardioplegia was administered into the aortic root following aortic occlusion in all patients. Twenty-two patients also received retrograde cardioplegia, administered through the right atrium. The echo-contrast agent consisted of a stable suspension of 5% human albumin microbubbles with a concentration of 4 x 10(8) microbubbles/ml and a diameter of 4 +/- 1 mu. RESULTS: Antegrade cardioplegia was not associated with aortic regurgitation in 23 of 40 (58%) patients. Seven patients (17%) had only mild aortic regurgitation, four patients (10%) had moderate regurgitation, and six (15%) had severe aortic regurgitation. The percent of myocardial opacification was 76.0 +/- 10.5 in the 23 patients who did not have aortic regurgitation, 76.0 +/- 17.0 in the 7 patients who had mild regurgitation, 52.5 +/- 18.1 in the 4 patients who had moderate regurgitation, and 48.5 +/- 18.3 in 6 patients who had severe aortic regurgitation (Kruskal-Wallis stat, 12.9; P < 0.005). Retrograde cardioplegia was not associated with right-to-left shunt in 11 of 22 patients (50%). In seven patients (32%), there was only a mild passage of contrast material to the left atrium. In the remaining four patients (18%), there was a moderate (one patient) to severe (three patients) right-to-left shunt at the level of the fossa ovalis. CONCLUSIONS: This study shows that incomplete myocardial distribution of cardioplegia, secondary to transient aortic valve incompetence or shunting through the foramen ovale, is not uncommon in patients undergoing coronary surgery.

Cardioplegic Solutions↗

PubMed1993

Testing practices and spread of HIV among sexual partners of HIV-positive haemophiliacs in Italy. Gruppo Italiano Coagulopatie Congenite.

OBJECTIVES: To evaluate rates and predictors of testing and HIV positivity among the sexual partners of Italian HIV-positive haemophiliacs. METHODS: Our index cases were 602 sexually active HIV-positive haemophiliacs (aged 18 years or more) enrolled in the Italian Registry of Haemophilia. Data on the demographic and clinical status of the haemophiliacs, whether their partners had undergone HIV testing, and the results of these tests were collected. RESULTS: To date, 205 (34.1%) partners of HIV-positive haemophiliacs have been tested for HIV, of whom 27 (13.2%) were seropositive. On univariate analysis, haemophiliacs who were unmarried, younger, and asymptomatic were less likely to have partners who had been tested for HIV (P << 0.001). On multivariate analysis, unmarried status [odds ratio (OR), 8.4; 95% confidence interval (CI), 5.4-13.1; P << 0.001] and younger age (OR, 1.9; 95% CI, 1.1-3.2) again predicted a higher rate of non-tested partners. There was no association between the demographic and medical characteristics of HIV-seropositive haemophiliacs and the risk of HIV positivity among their sexual partners. CONCLUSION: This study demonstrates that a high proportion of sexual partners of HIV-positive haemophiliacs have not yet been tested for HIV. The single most important predictor of not being tested was the marital status of the index case. These results emphasize the need to strengthen prevention programmes aimed at minimizing the risk of heterosexual HIV transmission, particularly among younger unmarried haemophiliacs.

AIDS Serodiagnosis↗

PubMed1993

[Anterograde and retrograde cardioplegia in myocardial revascularization. An intraoperative contrast echographic study].

The aim of this study was to assess the distribution of antegrade and retrograde cardioplegia with intraoperative contrast echocardiography in patients undergoing coronary artery bypass grafting. Fifteen patients with chronic stable angina pectoris and severe coronary artery disease were studied. The severity of coronary artery disease was assessed at coronary angiography, using the Jeopardy Score System. The presence and the extent of collateral circulation was evaluated on the basis of preoperative coronary angiography and graded as: absent or poor; good or excellent. Coronary revascularization was carried out during extracorporeal circulation and myocardial protection was performed with antegrade (aortic root) and retrograde (right atrial) cardioplegia. The echo contrast agent was sterilely prepared 1 hour prior to surgery and consisted of a solution of sonicated 5% human albumin microbubbles. Two ml of sonicated albumin were injected along with antegrade cardioplegia and 4 ml with retrograde cardioplegia. The echocardiographic images were obtained with transesophageal echocardiography in the transgastric left ventricular short-axis view. Images were recorded on videotape for off-line planimetric measurement of percent myocardial opacification. Data were analyzed with the analysis of variance. Multiple comparisons were made with Student's paired t test and using Bonferroni's correction. Myocardial opacification was 58.9 +/- 12.9% during antegrade cardioplegia and 77.5 +/- 16.4% during retrograde cardioplegia (p = 0.003). This overall difference was mainly due to the impact of collateral circulation in the distribution of antegrade cardioplegia. Patients with absent or poor collateral circulation showed a lower degree of myocardial opacification than patients with good or excellent myocardial opacification (44.3 +/- 12.0% versus 64.2 +/- 8.6%; p < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1992

Effects of different parametric estimates of seroconversion time on analysis of progression to AIDS among Italian HIV-positive haemophiliacs.

The purpose of this study was to estimate seroconversion time using different parametric methods and to assess their influence on the estimation of the incubation time between HIV infection and onset of AIDS. Study subjects were 712 HIV-positive haemophiliacs enrolled in the Italian National Registry of patients with congenital coagulation disorders. Seroconversion time was estimated using the mid-point of each seroconversion interval (MID), the median of each interval under an estimated uniform distribution with cutpoints at December 1981 and December 1985 (MUU), the median of each interval under an estimated Weibull distribution (MUW), and the median of three random values drawn from each interval under the Weibull distribution (RUW). Kaplan-Meier survival analysis showed that the cumulative incidence of AIDS over a 7-year period was 11.6 per cent (SE 1.3 per cent) when using the MID estimate of seroconversion time, 10.8 per cent (1.2 per cent) with the MUU estimate, and 13.4 per cent (1.3 per cent) and 12.3 per cent (1.3 per cent) when using MUW and RUW estimates, respectively. This study demonstrates that the estimate of seroconversion time does not seem to be a major factor affecting estimates of AIDS incidence since the different techniques for estimating HIV seroconversion time yielded very similar results.

Acquired Immunodeficiency Syndrome↗

PubMed1992

Selective changes in mouse behavioral development after prenatal benzodiazepine exposure: a progress report.

1. Animal studies of the effects of early exposure to CNS agents devoid of a major teratogenic potential must assess possible deviations from normal behavioral development in both a stage-specific and a behavior-specific fashion; several experiments on prenatal benzodiazepine (BDZ) exposure are reviewed, illustrating such an assessment strategy and discussing caveats on experimental designs and statistical analysis. 2. The offspring of mouse dams treated in late pregnancy with oxazepam (15 mg/kg p.o. twice daily on days 12-16) show a mild and reversible impairment in somatic and neurobehavioral development which is unlikely to be responsible for a series of other more specific changes. 3. The treatment produces a selective reduction of locomotor activity and amphetamine hyperactivity at the end of the second postnatal week, as well as a selective impairment of active avoidance at the young adult stage, in the absence of similar changes in scopolamine hyperactivity and passive avoidance. 4. The treatment also prevents the appearance at 28 days of morphine hyperactivity and of rebound hyperactivity after muscimol depression, without modifying the developmental profile of pain reactivity and of morphine and muscimol analgesia. 5. Young adult females previously exposed to oxazepam in utero show a marked enhancement of maternal aggression towards male intruders; mother-pup interactions are also modified, leading either to reduced or to exaggerated maternal care as a function of fostering procedures. 6. Overall, several effects of prenatal BDZ exposure appear to be amenable to modifications in monoaminergic system functions and/or to an accelerated development of GABAergic mechanisms; some of the changes in social and parental interactions, however, point to subtle modifications in the balance between different components of the fear-defensive repertoire, possibly due to an altered stimulus reactivity by mechanisms which are still poorly understood.

Animals↗

PubMed1992

High-intensity nociceptive stimuli minimize behavioral effects induced by restraining stress during the tail-flick test.

Analgesia following exposure to various stressors is a well-documented phenomenon. Restraint of an animal during the tail-flick test (TFT) represents a potent stressor that can induce both altered baseline latencies and enhanced response to opioids. The present study shows that the use of higher stimulus intensities during TFT minimizes the stress influences produced by restraint on the animal's response rendering the test more sensitive to the pharmacological action of analgesic drugs.

Animals↗

PubMed1992

Transcranial Doppler in spontaneous attacks of migraine.

BACKGROUND AND PURPOSE: Our aim in this study was to compare headache-free and spontaneous migraine measurements of blood flow velocity and the pulsatility index in the anterior cerebral artery, middle cerebral artery, and posterior cerebral artery. METHODS: Thirty-one patients (nine having experienced migraine with aura and 22 migraine without aura) were studied in headache-free periods and during spontaneous migraine attacks with transcranial Doppler ultrasonography. RESULTS: During attacks of migraine with aura, blood flow velocities (particularly the diastolic velocity [p = 0.05]) were reduced while the pulsatility index increased (p = 0.05), whereas a generalized increase in diastolic velocity (p less than 0.02) and a decrease in the pulsatility index (p = 0.05) were observed during attacks of migraine without aura. Significant variations of blood pressure and heart rate were never found. CONCLUSIONS: These findings are consistent with constriction of resistance vessels in migraine with aura and dilatation of the vessels in migraine without aura. This disparity could be due to a difference between the two migraine types or could be related to the fact that in this study the time interval between headache onset and transcranial Doppler was shorter in the migraine-with-aura group. The latter explanation would apply if, in fact, both types of migraine evolve from hypoperfusion to hyperperfusion during their time course, although perhaps with a difference in intensity.

Adult↗