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Biomedical subjects

A Sansonetti

Publications and source records attributed to A Sansonetti.

At least 19 recordsLinked to original sources
PubMed2000

Role of basal ganglia and ectostriatum in the context-dependent properties of the optocollic reflex (OCR) in the pigeon (Columba livia): a lesion study.

The possible participation of basal ganglia and associated structures [dorsal striato-pallidum, nucleus spiriformis lateralis (SpL), ectostriatum] in the elaboration of the optocollic reflex (OCR) was investigated by making bilateral chemical lesions (ibotenic acid). Previous data have shown that both the slow and fast phases of the OCR are dependent on the behavioural context. The slow phase velocity (SPV) and the peak velocity of fast phases obtained in non-flying pigeons ('resting condition') were enhanced in pigeons in which a flying posture was experimentally provoked ('flying condition'). Therefore, the effect of lesions was analysed in pigeons standing in the 'resting' or 'flying' condition. In the 'resting' as in the 'flying' condition, all the lesions provoked a decrease in SPV, which augmented with the stimulation velocity. Velocity step stimuli revealed greater OCR deficits than velocity ramp stimuli. Extensive lesions (including the striato-pallidum, ectostriatum and a part of the neostriatum), as well as SpL lesions, provoked a greater SPV decrease over a longer time than lesions restricted to the striato-pallidum or the ectostriatum. The peak velocity of fast phases was only reduced by the 'extensive lesion' in the 'flying condition'. The present data show that the basal ganglia system is involved in the elaboration of optokinetic responses and suggest that, to work in an optimal range, the optokinetic centres need to receive integrated information from basal ganglia in addition to direct visual input.

Animals↗
PubMed1999

Characteristics of slow and fast phases of the optocollic reflex (OCR) in head free pigeons (Columba livia): influence of flight behaviour.

The effect of behavioural context on the properties of slow and fast phases of the horizontal optocollic reflex (OCR) were investigated in head free pigeons for two situations, i.e.: (i) animals were hung in a harness ('resting condition'); (ii) animals were additionally submitted to a frontal airflow that provoked a flight posture ('flying condition') [Bilo and Bilo (1983) J. Comp. Physiol., 153, 111]. A 'transient flight' was also provoked in the 'resting condition' by tapping the breastbone region. Stimuli consisted either of velocity steps (30-300 degrees/s) or of an increasing velocity stimulus (0-300 degrees/s). The amplitude of nystagmic beats and the OCR gain increased in the 'flying condition' and during 'transient flight' as compared to the 'resting condition'. The OCR working range was considerably extended toward high velocities by the flying behaviour. In the 'resting condition', spontaneous head oscillations generally triggered a high-gain OCR, close to that obtained in the 'flying condition'. One-third of the animals showed a higher gain in response to an increasing velocity stimulus than with step stimuli, in the high velocity range. The linear relation between amplitude and peak velocity of OCR fast phases was independent of the stimulation velocity in the 'resting condition', whereas the amplitude and peak velocity increased with the stimulation velocity in the 'flying condition'. In this condition, the fast phase velocity was correlated with the slow phase velocity, but not with the retinal slip velocity. Thus, both the slow and fast phases of the OCR are dependent on the behavioural context.

Animals↗
PubMed1998

Oculocardiac reflex and postoperative vomiting in paediatric strabismus surgery. A randomised controlled trial comparing four anaesthetic techniques.

BACKGROUND: Oculocardiac reflex (OCR) and postoperative vomiting are major complications of paediatric strabismus surgery. METHODS: Children (3-16 yr) undergoing elective strabismus surgery as inpatients were randomly allocated to four anaesthetic techniques: (A) thiopentone induction and isoflurane maintenance; (B) as (A) plus ondansetron 5 mg x m(-2) i.v.; (C) propofol induction and maintenance; (D) as (C) plus lignocaine 2 mg x kg(-1) i.v. All children received prophylactic atropine 0.02 mg x kg(-1) and alfentanil. Nitrous oxide was omitted. RESULTS: Data on 157 children were analysed. The cumulative incidence of vomiting within 6 and 24 h after surgery with thiopentone-isoflurane was 26% and 46%, respectively. Adding ondansetron decreased the incidence to 8% and 33%, respectively. This improvement was significant within 6 h only; the number-needed-to-treat was 5.5 (95% CI 2.9-46). Propofol was not different from thiopentone-isoflurane. The addition of lignocaine to propofol was of no benefit. The risk of an OCR was significantly increased with propofol (incidence 40%) compared with isoflurane (14%); the number-needed-to-harm was 3.9 (95% CI 2.6-8). CONCLUSIONS: Thiopental-isoflurane-air/O2-alfentanil resulted in a moderate risk of vomiting. Adding ondansetron significantly decreased this risk, but 6 children have to be treated for one to benefit in the early postoperative period. Propofol and propofol-lignocaine showed no benefit on vomiting but significantly increased the risk of an OCR despite high-dose prophylactic atropine.

Adolescent↗
PubMed1997

Low incidence of the oculocardiac reflex and postoperative nausea and vomiting in adults undergoing strabismus surgery.

PURPOSE: To investigate the incidence of the oculocardiac reflex (OCR), and of postoperative nausea and vomiting (PONV) in adults undergoing strabismus surgery. METHODS: Adults (18-86 yr) undergoing inpatient strabismus surgery received 10 micrograms.kg-1 atropine and 10 micrograms.kg-1 altentanil iv and were randomly allocated to: (A) 5 mg.kg-1 thiopentone iv, isoflurane/N2O maintenance; (B) 3 mg.kg-1 propofol iv, propofol/N2O maintenance (10-14 mg.kg-1.hr-1); 3 mg.kg-1 propofol iv, propofol/air/O2 maintenance (10-14 mg.kg-1.hr-1). Analyses were with the number-needed-to-treat/harm. RESULTS: In 97 adults the absolute risk of OCR (13-20%) and PONV (21-31% after 24 hr) was low, with no differences between groups. Number-needed-to-treat to prevent PONV with propofol with or without N2O compared with thiopentone-isoflurane was 7 to 11. Number-needed-to-harm for one OCR with propofol compared with thiopentone-isoflurane was 17. CONCLUSION: Adults undergoing strabismus surgery with prophylactic atropine had a low risk of OCR and PONV, independent of the anaesthetic technique used.

Adolescent↗
PubMed1997

Cytomegalovirus retinitis: decreased risk of bilaterality with increased use of systemic treatment. Swiss HIV Cohort Study Group.

Cytomegalovirus (CMV) retinitis may be treated systemically or intravitreally. We reviewed retrospectively patients with CMV retinitis, in order to determine whether systemic treatment was associated with less spread of CMV retinitis from one eye to the other. Of 222 cases, 92 patients had bilateral disease at onset of CMV retinitis, leaving 130 for analysis. Bilaterality occurred in 10 patients during 12,687 days of systemic treatment and in 34 during 14,791 days without systemic treatment (odds ratio [OR] = 2.92; confidence interval [CI], 1.44-5.90). Patients who had received systemic treatment for <50% of the follow-up period had a greater risk of bilaterality (OR = 3.7; CI, 2.79-4.54) than did the more intensively treated patients. CD4 cell levels also contributed to increased risk, but multivariate analysis showed that CD4 cell counts and treatment intensity were independent risk factors. CMV retinitis was more likely to become bilateral in patients who received less intravenous therapy. Local treatment can complete but does not replace systemically administered therapy.

Adult↗
PubMed1995

Developmental, nutritional, and hormonal regulation of the pancreatitis-associated protein I and III gene expression in the rat small intestine.

BACKGROUND: The pancreatitis-associated protein (PAP) I and III, but not PAP II, mRNAs are constitutively expressed in the small intestine of rats. METHODS: We studied expression of both PAP I and PAP III mRNAs during development and on nutritional and hormonal manipulations. RESULTS: Between day 20 of gestation and day 21 of age, PAP mRNAs could barely be detected. Their concentrations increased dramatically from day 21 to day 45 of age and remained constant thereafter. Rats adapted to a diet with low carbohydrate content showed a significant decrease in PAP mRNA concentrations. Finally, whereas thyroidectomy and ovariectomy induced a decrease in both mRNA concentrations, and adrenalectomy a limited decrease in PAP III mRNA only, diabetes and castration did not alter the expression of either gene. CONCLUSION: Gene expression of PAP I and III mRNAs is regulated in a coordinate manner in the rat small intestine during development and on nutritional and hormonal manipulations.

Acute-Phase Proteins↗
PubMed1994

[Diagnostic aspects and frequency of retrocorneal precipitates in diagnosis of cytomegalovirus retinitis in the HIV+ patient].

Cytomegalovirus retinitis (CMV) is the most common ocular opportunistic infection seen in patients with acquired immune deficiency syndrome. The anterior segment is usually quiet or with minimal aqueous humour flare and cell reaction. Nevertheless, in this prospective study of 30 eyes with CMV retinitis, 22 (73%) had white, small and filamentous keratic precipitates (KPS) which seem to corroborate this inflammation. The positivity of the KPS depends upon the extent of CMV retinitis.

AIDS-Related Opportunistic Infections↗
PubMed1994

[Prosthetic repair of hernias and laparocele. Our experience with Goretex prosthesis].

For about ten years repair of inguinal or abdominal hernias using prosthetic materials has been in routine use in general surgery. Various experimental and clinical observations of surgical physiopathology have been proved that the most important cause of recidivation is abnormal tension between diastasis tissues. From the beginning of 1991, in the Surgical Department of "Clinica S. Anna" in Pomezia (Rome), we have been using tension free technique. Goretex was preferred versus other prosthetic devices because of our experience in vascular surgery. Hundred-fifteen operations have been carried out; 23 for ventral hernias, 92 for inguinal and femoral hernias. The age of patients varied from 18 to 69 years. Localization of inguinal hernias was indirect in 48 cases, direct in 16 an associated in 13; 9 were recidive and 3 bilateral, 3 femoral hernias. Abdominal wall hernias consisted of 12 epigastric localizations, 8 hypogastric and 3 pararectal. All cases of abdominal and bilateral hernias were operated under general anesthesia with orotracheal intubation. Inguinal hernias were treated with local (pubivacaine 0.5%, 1:2 with physiologic solution) or spinal anesthesia, except for 2 cases operated in total anesthesia. As regards surgical technique, the objective pursued was that of filling up the parietal defect with a patch of the same form fixed with a non absorbable suture in Goretex 2/0. The peritoneum was not opened in abdominal hernias, if not necessary, because prosthetic devices must not touch directly the small and large bowel; patches have been positioned between the peritoneum and transversalis aponeurosis. For inguinal hernias Rives' technique was used. Goretex patches were cut with "no-touch" technique.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

A gene homologous to the reg gene is expressed in the human pancreas.

We have determined the nucleotide sequence of regl a human genomic DNA fragment homologous to the reg gene which is expressed in the exocrine pancreas and regenerating islets. Sequence comparisons of reg and regl suggested similar exon-intron organisation. Based on this assumption, specific oligonucleotides for regl exons were used to demonstrate expression of the regl gene in pancreas and liver. The proteins encoded by reg and regl comprise 166 amino acids and differ by 22 amino acids only.

Amino Acid Sequence↗
PubMed1993

Topical timolol maleate might adversely affect serum lipoproteins.

Conflicting observations have been reported about the effects of topically administered timolol maleate on serum lipoproteins. We therefore considered this issue in a series of eight glaucoma patients receiving timolol maleate. Cholesterol and triglycerides were measured in plasma and in low-density lipoproteins (LDL), and high-density lipoproteins (HDL), both before and following three months of treatment. Following the treatment, the mean atherogenic index was increased from 2.72 to 3.38 (p = 0.012). This suggests that the atherogenic index should be determined before and during timolol maleate treatment in high-risk cardiovascular patients.

Administration, Topical↗
PubMed1993

Human regeneration protein/lithostathine genes map to chromosome 2p12.

The pancreatic stone protein (lithostathine) secreted by the exocrine pancreas is an inhibitor of CaCO3 crystal growth. This protein, which is also present in endocrine pancreas, has also been called the regeneration protein (reg). Here we report the mapping of the REG gene to chromosome 2 using the polymerase chain reaction for the specific amplification of human reg sequences in rodent/human somatic cell hybrid DNA. A regional assignment has been made by in situ hybridization to metaphase chromosomes using two different fluorescently labelled genomic probes corresponding to the REG gene and a related gene REGL. Both probes hybridized to chromosome 2p12 suggesting the tandem organization of these genes.

Animals↗
PubMed1993

[Update on laparoscopic surgery: on the treatment of hydatid cyst of the liver and peritonitis caused by a perforated duodenal ulcer].

Laparoscopic surgery represents a real innovation with respect to the traditional laparotomic way of access, owing to its undeniable advantages, both intraoperative and postoperative. This new technique reduces the complications connected with the surgical wound and with forced allerement. Therefore it allows the patient's fast recovery. Laparoscopic surgery application ground get's wider and wider every day: in fact, the authors report two medical cases, one of elective surgery (treatment of a hidatid cyst of the liver) and the other in emergency surgery (peritonitis due to perforated duodenal ulcer), both obtaining a positive result about the clinical and the postoperative timing of recovery.

Duodenal Ulcer↗
PubMed1992

Spontaneous saccades under different visual conditions in the pigeon.

Spontaneous saccades of both eyes were recorded in head-restrained pigeons placed in 6 different visual conditions (darkness and biocular, uniocular, frontal or lateral viewing). Most saccades (95%) were biocular and directed forward (around the beak axis) and backward (around the horizontal line). In the dark, the proportions of forward and backward saccades were different, they became symmetrical when the visual input involved either the left eye, the lateral fields or both eyes. This spatial reorganization could be mediated by one 'dominant' eye through the lateral and foveal vision. Although some biocular saccades were strictly convergent, divergent or conjugate, most of them showed a higher independence since they had different directions and amplitudes for each eye.

Animals↗
PubMed1991

Role of the nucleus geniculatus lateralis ventralis (GLv) in the optokinetic reflex: a lesion study in the pigeon.

Several functions have been proposed for the avian GLv (color vision, pupillary reflex, optomotor mechanisms). In the present paper we have examined the role of the GLv in optomotor responses. For this purpose, horizontal and vertical optokinetic nystagmus (OKN) were quantified in response to different stimulation velocities, before and after chemical (kainic acid) lesions. Unilateral lesion of the GLv produced a marked increase of the horizontal OKN gain when the eye contralateral to the lesion was stimulated in the temporonasal (T-N) direction and, to a lesser extent, when the ipsilateral eye was stimulated in the naso-temporal (N-T) direction. Biocular integration was reduced after the lesion, since the biocular stimulation corresponding to these two monocular stimulations (ipsiversive to the lesion) produced only a moderate gain increase. When stimulations were delivered in the opposite direction (contraversive to the lesion), the horizontal OKN gain was slightly increased for the N-T monocular stimulation of the eye contralateral to the lesion, but was unchanged for other stimulations. A bilateral lesion of the GLv provoked only a slight increase of the horizontal OKN gain. The vertical OKN was not affected by the GLv lesions. Thus, the GLv system is probably involved in the modulation of optomotor responses and could mediate visuo-optokinetic interactions, each nucleus (and its associated system) exerting an inhibitory (or disfacilitatory) effect on the horizontal OKN in one direction.

Animals↗