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Biomedical subjects

F Iannotti

Publications and source records attributed to F Iannotti.

At least 19 recordsLinked to original sources

Effects of gonadotropin-releasing hormone agonists on uterine volume and vasculature and on the immunohistochemical expression of basic fibroblast growth factor (bFGF) in uterine leiomyomas.

We investigated the effect of the GnRH agonist (GnRH-a) on the uterine volume and on the immunohistochemical expression of basic fibroblast growth factor (bFGF) and the vasculature of leiomyomas. Twenty-five women were treated with leuprorelin acetate for 3 months; 46 untreated patients were enrolled as a control group. The uterine volume was measured by ultrasonography. After myomectomy or hysterectomy, the immunoexpression of bFGF and the endothelial marker, CD34, was studied and compared in treated and untreated leiomyomas. Uterine volume decreased after therapy. The number of cells expressing bFGF and the vascularity were diminished in treated leiomyomas. Reduction in the blood supply might be responsible, in part, for uterine-volume shrinkage after GnRH-a therapy.

Adult↗

[Prenatal telemedicine and teledidactic networking. A report on the TOCOMAT project].

Telemedicine originates with the combined use of electromedical equipment, information technologies and telecommunication systems designed to improve healthcare by overcoming the limitations of time and space. Moreover, telemedicine also possesses greater didactic potential than instruction by traditional means. Teledidactic networking, both as e-learning and e-teaching, represents a new integrated system of computer-aided education for the development and management of distance learning programs. Our study evaluated the effectiveness of teledidactic applications in the first Italian project in conventional and computerized telecardiotocography (TOCOMAT). Five cardiotocography outpatient monitoring facilities were linked telematically to a university central operating unit to obtain computerized analysis of telecardiotocographic (CTG) tracings and specialist consulting. The peripheral site operators received theoretical-practical training in the function and use of the system, the guidelines for CTG tracing interpretation and the diagnostic-therapeutic protocols. Improvement in learning progress was observed in the reduction of technical errors in CTG recording and in the increased ability of the outpatient clinic staff to select, analyze and interpret test RESULTS. Results from the feedback questionnaires on the didactic impact of the project indicated objective improvement in the specific skills acquired by the physicians at these facilities. The findings also show that a well-structured distance learning course can improve clinical, technical and managerial skills and behavior of healthcare operators by promoting the kind of professional continuing education a modern medical school should provide.

Female↗

Interleukin-1beta exacerbates hypoxia-induced neuronal damage, but attenuates toxicity produced by simulated ischaemia and excitotoxicity in rat organotypic hippocampal slice cultures.

Using organotypic hippocampal slice cultures we have investigated the actions of Interleukin-1 (IL-1) in a number of injury paradigms. Low concentrations of IL-1 potentiated hypoxia-induced neurodegeneration whilst high concentrations had no effect. In contrast, higher concentrations of IL-1 were strongly neuroprotective in models of combined oxygen/glucose deprivation and N-methyl-D-aspartate toxicity, but no potentiation was observed at low IL-1 concentrations. Both protective and toxic effects of IL-1 were fully antagonized by IL-1 receptor antagonist. These data demonstrate that the effects of IL-1 on neuronal injury are complex, and may be directly related to the injury paradigm studied.

Animals↗

Intensive care management of head-injured patients in Europe: a survey from the European brain injury consortium.

OBJECTIVES: (a) to describe current practice in the monitoring and treatment of moderate and severe head injuries in Europe; (b) to report on intracranial pressure and cerebral perfusion pressure monitoring, occurrence of measured and reported intracranial hypertension, and complications related to this monitoring; (c) to investigate the relationship between the severity of injury, the frequency of monitoring and management, and outcome. METHODS: A three-page questionnaire comprising 60 items of information has been compiled by 67 centres in 12 European countries. Information was collected prospectively regarding all severe and moderate head injuries in adults (> 16 years) admitted to neurosurgery within 24 h of injury. A total of 1005 adult head injury cases were enrolled in the study from 1 February 1995 to 30 April 1995. The Glasgow Outcome Scale was administered at 6 months. RESULTS: Early surgery was performed in 346 cases (35%); arterial pressure was monitored invasively in 631 (68%), ICP in 346 (37%), and jugular bulb saturation in 173 (18%). Artificial ventilation was provided to 736 patients (78%). Intracranial hypertension was noted in 55% of patients in whom ICP was recorded, while it was suspected in only 12% of cases without ICP measurement. There were great differences in the use of ventilation and CPP monitoring among the centres. Mortality at 6 months was 31%. There was an association between an increased frequency of monitoring and intervention and an increased severity of injury; correspondingly, patients who more frequently underwent monitoring and ventilation had a less favourable outcome. CONCLUSIONS: In Europe there are great differences between centres in the frequency of CPP monitoring and ventilatory support applied to head-injured patients. ICP measurement disclosed a high rate of intracranial hypertension, which was not suspected in patients evaluated on a clinical basis alone. ICP monitoring was associated with a low rate of complications. Cases with severe neurological impairment, and with the worse outcome, were treated and monitored more intensively.

Adult↗

Polymorphisms in matrix metalloproteinase-1, -3, -9, and -12 genes in relation to subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Intracranial aneurysm, which underlies the vast majority of subarachnoid hemorrhage incidences, has a multifactorial etiology, and the importance of genetic factors is increasingly recognized. Development and rupture of intracranial aneurysms involve degradation and remodeling of the vascular wall matrix in which the matrix metalloproteinases (MMPs) play an important role. The possible impact of MMP gene polymorphisms on susceptibility to intracranial aneurysms is still controversial, with conflicting data from different reported studies. METHODS: In this study we analyzed 5 different functional promoter polymorphisms in the MMP-1, MMP-3, MMP-9, and MMP-12 genes in a sample of 92 patients with aneurysmal subarachnoid hemorrhage and 158 healthy control subjects, all from southern England. RESULTS: No significant difference was detected between the patient and control groups in genotype distribution of any of the polymorphisms studied. CONCLUSIONS: The data do not support the hypothesis that MMP gene variations influence the development of intracranial aneurysms in the population studied.

Adult↗

Reducing conditions produce a loss of neuroprotective efficacy of competitive but not non-competitive antagonists in a model of NMDA-mediated excitotoxicity in organotypic hippocampal slice cultures.

Experimental data indicate that NMDA receptor activation is strongly implicated in the pathogenesis of cerebral ischaemia. However, the results from in vivo studies are equivocal, with NMDA antagonists being active in only some models. It has recently been demonstrated that competitive and non-competitive NMDA antagonists behave differently under normal and ischaemic conditions. These studies have used organotypic hippocampal slice cultures to investigate whether this disparity is due to redox-modulation of the NMDA receptor which occurs in ischaemia. NMDA-mediated toxicity was concentration dependent with little damage occurring with less than 10 microM NMDA and maximal damage produced by 30 microM. NMDA toxicity was significantly enhanced by pre-treatment with 1 mM dithiothreitol, a reducing agent, such that damage occurred at 1 nM NMDA, and maximal damage was produced by 10 microM. The efficacy of MK-801 was not altered by reducing conditions, but the EC50 of the competitive antagonist APV was increased by 20-fold. These data strongly suggest that the neuroprotective efficacy of NMDA antagonists is significantly altered under ischaemic conditions, and that more beneficial effects will be obtained with antagonists having a higher affinity for the receptor in the reduced configuration.

Animals↗

Reducing conditions significantly attenuate the neuroprotective efficacy of competitive, but not other NMDA receptor antagonists in vitro.

Inappropriate activation of NMDA receptors during a period of cerebral ischaemia is a crucial event in the pathway leading to neuronal degeneration. However, significant research has failed to deliver a clinically active NMDA receptor antagonist, and competitive NMDA antagonists are ineffective in many experimental models of ischaemia. The NMDA receptor itself has a number of modulatory sites which may affect receptor function under ischaemic conditions. Using rat organotypic hippocampal slice cultures we have investigated whether the redox modulatory site affects the neuroprotective efficacy of NMDA receptor antagonists against excitotoxicity and experimental ischaemia (OGD). NMDA toxicity was significantly enhanced in cultures pretreated with a reducing agent. The noncompetitive antagonist MK-801 and a glycine-site blocker were equally neuroprotective in both normal and reduced conditions, but there was a significant rightward shift in the dose-response curves of the competitive antagonists APV and CPP and the uncompetitive antagonist memantine. OGD produced neuronal damage predominantly in the CA1 region, which was prevented by MK-801 and memantine, but not by APV or CPP. Inclusion of an oxidizing agent during the period of OGD had no effect alone, but significantly enhanced the neuroprotective potency of the competitive antagonists. These data clearly demonstrate that chemical reduction of the redox modulatory site of the NMDA receptor decreases the ability of competitive antagonists to block NMDA receptor-mediated neuronal damage, and that the reducing conditions which occur during simulated ischaemia are sufficient to produce a similar effect. This may have important implications for the design of future neuroprotective agents.

2-Amino-5-phosphonovalerate↗

Attenuation and augmentation of ischaemia-related neuronal death by tumour necrosis factor-alpha in vitro.

Upregulation of the pro-inflammatory cytokine tumour necrosis factor-alpha (TNF) occurs rapidly in the brain following ischaemia, although it is unclear whether this represents a neurotoxic or neuroprotective response. We have investigated whether TNF has different actions in the pre- and postischaemic periods in a tissue culture model of cerebral ischaemia. Organotypic hippocampal slice cultures were prepared from 8-10-day-old rats and maintained in vitro for 14 days. Neuronal damage was induced by either 1 h oxygen-glucose deprivation or 3 h exposure to NMDA or the superoxide generator duroquinone, and assessed after 24 h by propidium iodide fluorescence. TNF pretreatment was neuroprotective against both oxygen-glucose deprivation and duroquinone. This effect was associated with an activation of the transcription factor NFkappaB and upregulation of manganese superoxide dismutase, and was prevented by a free radical scavenger. When addition of TNF was delayed until the postinsult period, an exacerbation of neurotoxicity occurred, which was also prevented by a free radical scavenger. The actions of TNF are determined by whether TNF is present before or after an ischaemia-related insult. Both actions are mediated through the production of free radicals, and the response to TNF is determined by whether a cell is metabolically competent to respond by synthesis of antioxidant defences.

Animals↗

The value of the "worst" computed tomographic scan in clinical studies of moderate and severe head injury. European Brain Injury Consortium.

OBJECTIVE: Computed tomographic (CT) scanning can reveal the pattern and severity of structural brain damage after head injury. With the proliferation of CT scanners in general hospitals, and with improvements in patient transport, the interval from injury to the first CT scan is decreasing. The potential result is an "admission" scan missing an evolving and potentially operable lesion. Furthermore, the literature is confusing regarding the timing and coding of CT findings. We sought to establish the frequency of deterioration in CT appearance from an admission scan to subsequent scans and the prognostic significance of such deterioration. METHODS: In a survey organized by the European Brain Injury Consortium, data on initial severity, management, and subsequent outcome were gathered prospectively for 1005 patients with moderate or severe head injury admitted to one of 67 European neurosurgical units during a 3-month period in 1995. The findings of the initial and the final ("worst") CT scan were classified according to the Traumatic Coma Data Bank system and were related to outcome as assessed using the Glasgow Outcome Scale 6 months after injury. RESULTS: Data on an initial and a final CT scan were available for 897 patients; of these, 724 patients were assessed using the Glasgow Outcome Scale at 6 months. The initial CT findings were classified as a diffuse injury for 53% of the cohort, with 16% of these diffuse injuries demonstrating deterioration on a subsequent scan. In 56 (74%) of 76 deteriorations, the change was from a diffuse injury to a mass lesion. When the initial CT scan demonstrated a diffuse injury without swelling or shift, evolution to a mass lesion was associated with a statistically significant increase in the risk of an unfavorable outcome (62% versus 38%). When the initial scan demonstrated evidence of swelling or shift, there was a nonsignificant trend in the opposite direction, although the numbers were limited. CONCLUSION: When an admission CT scan demonstrates evidence of a diffuse injury, follow-up scans should be performed, because approximately one in six such patients will demonstrate significant CT evolution. In studies comparing series of head-injured patients, correspondence of timing of CT scans is necessary for valid comparison.

Brain Injuries↗

Ischaemic pre-conditioning in organotypic hippocampal slice cultures is inversely correlated to the induction of the 72 kDa heat shock protein (HSP72).

In vivo, preconditioning with a sublethal insult can confer resistance to normally lethal episodes of cerebral ischaemia. This phenomenon has been linked with the induction of the 72 kDa heat shock protein (HSP72), but this has not been clearly demonstrated in vitro. We have used organotypic hippocampal slice cultures to investigate whether tolerance to lethal ischaemia is dependent on HSP72. Cultures were maintained in vitro for 14 days, and neuronal damage assessed using propidium iodide fluorescence. Prolonged neuronal HSP72 upregulation occurred following exposure to 30 min ischaemia, 45 min hypoxia and 1 microM kainate, but not 1 microM NMDA or 20 min ischaemia, all sublethal insults. Preconditioning with ischaemia, kainate or hypoxia 24 h prior to lethal ischaemia (45 min) was not protective, and when the delay was increased to 48 h, damage in the CA3 pyramidal cell region was significantly increased compared to cultures exposed to 45 min ischaemia alone. Preconditioning with 20 min ischaemia had no effect on the severity of ischaemic damage. Preconditioning with 1 microM NMDA significantly reduced neuronal damage produced by either 45 or 60 min ischaemia when the delay between insults was 48 h. NMDA pre-treatment also prevented neurotoxicity produced by glutamate (5-10 mM) but not NMDA (10-30 microM). These data suggest that in vitro, the increased expression of HSP72 following some sublethal insults should be considered as a marker of cell stress prejudicial to the survival of neurones subsequently exposed to ischaemia, while tolerance can be produced through mechanisms independent of HSP72 induction.

Animals↗

Challenges in translating the efficacy of neuroprotective agents in experimental models into knowledge of clinical benefits in head injured patients.

Many agents have been shown to reduce brain damage in experimental models of brain injury; this is proving difficult to translate into improved outcome of patients for reasons that are reviewed in this article. It is possible that, even if fundamental mechanisms are similar, injury processes modelled experimentally may be proportionately less important in human cases, and there also may have been insufficient attention to ensuring that dosage regimens for patients are therapeutically appropriate both in terms of concentration and time window. The distribution of outcomes after head injury means that, in unselected populations, a proportional improvement to the extent usually sought may be difficult to achieve. Future studies may need to consider more extensive work in "targeted populations" (selected by type and severity of damage) as a preliminary step before proceeding to definitive studies of efficacy, in which expectations of effect need to be lower and correspondingly large numbers of patients studied. Recant experience in the evaluation of glutamate NMDA antagonists is reviewed.

Clinical Trials as Topic↗

The European Brain Injury Consortium survey of head injuries.

To provide a picture of contemporary practice, a survey was carried out of severely and moderately head injured patients admitted to 67 'neuro' centres in 12 European countries. 1,005 adult head injuries were recruited over a three month period. Sixty items of information on demography, clinical features, investigations, management and early complications were captured on a simple, two-page questionnaire and, information on outcome at six months on a third page. The median age of the subjects was 38 years, 74% were male and 51% injured in road traffic accidents; 57% of patients were transferred to the 'neuro' centre from another hospital. Assessment of clinical responsiveness was limited by the use of sedation and intubation and information from four early time points (pre-hospital, arrival at the Accident and Emergency department, post-resuscitation, and arrival at the 'neuro' unit) was combined to stratify the subjects as severe (58%), moderate (17%) or intermediate (19%). In 48% of patients classified the CT scan showed features of a 'mass lesion' and in 40% showed a subarachnoid haemorrhage. Fifty-five centres provided the data on outcome for 94% of the cases recruited in these centres six months after injury. 31% died, 3% were vegetative, 16% severely disabled, 20% moderately disabled and 31% had made a good recovery. Comparison of the data from different parts of Europe showed differences in the frequency of secondary transfer, cause of injury, occurrence of major extracranial injury, CT scan findings, intracranial operation, clinical severity of injury and utilisation of the components of intensive care and the occurrence of a favourable outcome, although the latter difference was not statistically significant when variations in the initial severity of injury were taken into account. The findings in the present survey are compared with newly analysed information for three previous large series: the International Data Bank involving the UK, the Netherlands and the USA, the North American Traumatic Coma Data Bank, and data from four centres in the UK. The comparisons showed substantial similarities and also differences that may reflect variations in policy for admission of the head injury to 'neuro' units, and evolution in methods of assessment, investigation and management. The effects of these differences on outcome requires further, rigorous prospective study.

Adolescent↗

Middle cerebral artery occlusion in the rat causes a biphasic production of immunoreactive interleukin-1beta in the cerebral cortex.

Interleukin-1beta (IL-1beta) has been implicated in the sequence of events leading to neuronal cell death. We have used an ultrasensitive, highly specific immunometric assay for rat IL-1beta to determine the pattern of protein expression in the rat cerebral cortex following middle cerebral artery occlusion. In the ipsilateral cerebral cortex there was a biphasic pattern of production with a rapid early phase of IL-1beta expression followed by a delayed phase at 4 h which was sustained for up to 72 h. There was a similar but smaller expression of IL-1beta in the contralateral cortex. Sham operated animals showed no IL-1beta expression. These results provide further evidence to show that IL-1beta is expressed in the rat cerebral cortex following cerebral ischaemia.

Animals↗

Outcome after aneurysmal subarachnoid haemorrhage: the use of a graphical model in the assessment of risk factors.

In 102 consecutive prospectively identified patients with subarachnoid haemorrhage (SAH) we have analysed the severity of the initial haemorrhage and the direct and indirect effects of adverse factors on outcome. The data we recorded included delay in diagnosis, risk groups, Doppler measurements, angiographic findings, surgical events and outcome at 1 year. By using a temporal graphical chain model, the associations between all variables and possible causal pathways were statistically determined. The severity of the initial haemorrhage, as determined by means of a clinical assessment and CT scanning, allowed low-, medium- and high-risk patient groups and a statistically predictable outcome to be identified. The overall management mortality was 13.7% at 1 year; 70.6% had a favourable outcome and 15.7% were severely disabled. Outcome was directly associated with risk group (p = 0.0038) and rebleeding (p = 0.0000). Delayed diagnosis led to a poorer outcome (p = 0.014)--an indirect association probably due to rebleeding. Adverse surgical events led to a significantly poorer outcome in high-risk patients. No significant relationship was found either between age and risk group (p = 0.7784) or between age and outcome (p = 0.6418). Preoperative clinical (WFNS) grade was unreliable in predicting outcome. It is the particular risk group, determined by the initial SAH, that indicates the individual patient's outcome. Management strategies can reduce preventable adverse events such diagnostic delay and rebleeding. Future studies should stratify patients according to risk group, delay in diagnosis and rebleeding in order to enable a clearer comparison to be made of treatment methods.

Adult↗

A multicenter trial on the efficacy of using tirilazad mesylate in cases of head injury.

OBJECT: The authors prospectively studied the efficacy of tirilazad mesylate, a novel aminosteroid, in humans with head injuries. METHODS: A cohort of 1120 head-injured patients received at least one dose of study medication (tirilazad or placebo). Eighty-five percent (957) of the patients had suffered a severe head injury (Glasgow Coma Scale [GCS] score 4-8) and 15% (163) had sustained a moderate head injury (GCS score 9-12). Six-month outcomes for the tirilazad- and placebo-treated groups for the Glasgow Outcome Scale categories of both good recovery and death showed no significant difference (good recovery in the tirilazad-treated group was 39% compared with the placebo group in which it was 42% [p=0.461]; death in the tirilazad-treated group occurred in 26% of patients compared with the placebo group, in which it occurred in 25% [p=0.750]). Subgroup analysis suggested that tirilazad mesylate may be effective in reducing mortality rates in males suffering from severe head injury with accompanying traumatic subarachnoid hemorrhage (death in the tirilazad-treated group occurred in 34% of patients; in the placebo group it occurred in 43% [p=0.026]). No significant differences in frequency or types of serious adverse events were shown between the treatment and placebo groups. CONCLUSIONS: Striking problems with imbalance concerning basic prognostic variables were observed in spite of the large population studied. These imbalances concerned pretreatment hypotension, pretreatment hypoxia, and the incidence of epidural hematomas. In future trials of pharmacological therapy for severe head injury, serious consideration must be given to alternative randomization strategies. Given the heterogeneous nature of head injury and the identification of populations that do relatively well with standard therapy, target populations with a higher risk for mortality and morbidity may be more suitable for clinical trials of such agents.

Adult↗

Neuroprotection by both NMDA and non-NMDA receptor antagonists in in vitro ischemia.

We have investigated the relative contributions of oxygen and glucose deprivation to ischaemic neurodegeneration in organotypic hippocampal slice cultures. Cultures prepared from 10-day-old rats were maintained in vitro for 14 days and then deprived of either oxygen (hypoxia), glucose (hypoglycaemia), or both oxygen and glucose (ischaemia). Hypoxia alone induced degeneration selectively in CA1 pyramidal cells and this was greatly potentiated if glucose was removed from the medium. We have also characterised the effects of both pre- and post-treatment using glutamate receptor antagonists and the sodium channel blocker tetrodotoxin (TTX). Neuronal death following either hypoxia or ischaemia was prevented by pre-incubation with CNQX, MK-801 or tetrodotoxin. MK-801 or CNQX also prevented death induced by either hypoxia or ischaemia if added immediately post-insult, however, post-insult addition of TTX prevented hypoxic but not ischaemic damage. Organotypic hippocampal slice cultures are sensitive to both NMDA and non-NMDA glutamate receptor blockade and thus represent a useful in vitro system for the study of ischaemic neurodegeneration paralleling results reported using in vivo models of ischaemia.

6-Cyano-7-nitroquinoxaline-2,3-dione↗