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Biomedical subjects

A Puca

Publications and source records attributed to A Puca.

At least 19 recordsLinked to original sources
PubMed2007

Middle cerebral artery dolichoectasia in a young woman with a previous stroke.

We observed a 32-year-old female who had suffered from a left hemisphere ischemic stroke with right hemiparesis at the age of seven. At that time, a CT scan demonstrated a left ischemic lesion in nucleo-capsular region and a cerebral angiogram documented a complete occlusion of the supraclinoid segment of the internal carotid artery. When we observed the patient neurological examination demonstrated a moderate right brachio-crural hemiparesis. A brain MRI showed an old ischemic lesion involving the left nucleo-capsular and 'flow voids' suggestive for a vascular malformation in the left sylvian region. A cerebral rotational angiogram with 3-D reconstructions demonstrated a dolichoectatic left middle cerebral artery with an unusual 'corkscrew' aspect. Middle cerebral artery dolichoectasia is a rare pathological condition that may manifest with a stroke. The patients with intracranial arterial dolichoectasia (IADE) are most often hypertensive elderly men, and, to the best of our knowledge, an ischemic stroke associated with IADE has never been reported in children.

Adult↗
PubMed2006

Intracranial meningiomas associated with non-traumatic chronic subdural hematoma.

BACKGROUND: Non-traumatic subdural hematomas are very rarely associated with intracranial meningiomas. Pathophysiological mechanisms of such an association are not yet fully understood. CASE DESCRIPTION: We report on two patients harboring an intracranial meningioma and ipsilateral non-traumatic chronic subdural hematoma. Their history was negative for risk factors for subdural hematoma. Both patients were submitted to surgery for evacuation of the subdural collection. The presence of the meningioma was discovered during surgery. A second operation was necessary in our first case. CONCLUSIONS: We retrospectively analyzed our radiological data and the literature to provide some features that may help in the pre-operative diagnosis of a meningioma in patients presenting with a chronic subdural hematoma. Furthermore the mechanisms responsible for this association are discussed on the basis of our pathological evidence.

Aged↗
PubMed2003

Effects of thyroid state on H2O2 production by rat heart mitochondria: sites of production with complex I- and complex II-linked substrates.

This work was designed to determine possible effects of altered thyroid states on rates and sites of H 2 O 2 production by rat heart mitochondria. Rates of O 2 consumption and H 2 O 2 release, capacities to remove the peroxide, lipid peroxidation, cytochrome oxidase activities and ubiquinone levels were determined in heart mitochondria from euthyroid, hypothyroid, and hyperthyroid rats. Hypothyroidism decreased, whereas hyperthyroidism increased the rates of O 2 consumption and H 2 O 2 release during both state 4 and state 3 respiration with Complex I- or Complex II-linked substrates. The percentage of O 2 released as H 2 O 2 was not significantly affected by thyroid state. However, the mitochondrial capacity to remove H 2 O 2 increased in the transition from hypothyroid to hyperthyroid state, which indicates that H 2 O 2 production did not modify in proportion to the rate of O 2 consumption. The thyroid-state-linked changes in H 2 O 2 production were well correlated with the levels of hydroperoxides. Rates of H 2 O 2 release in the presence of respiratory inhibitors indicated that changes in the H 2 O 2 production occurred at both sites at which H 2 O 2 was generated in euthyroid state. This result and the observation that ubiquinol levels and cytochrome oxidase activities increase in the transition from hypothyroid to hyperthyroid state suggest that the modifications of H 2 O 2 production are due to a modulation by thyroid hormone of mitochondrial content of autoxidisable electron carriers.

Animals↗
PubMed2000

Reinitiation of protein synthesis in Escherichia coli can be induced by mRNA cis-elements unrelated to canonical translation initiation signals.

In Eubacteria, de novo translation of some internal cistrons may be inefficient or impossible unless the 5' neighboring cistron is also translated (translational coupling). Translation reinitiation is an extreme case of translational coupling in which translation of a message depends entirely on the presence of a nearby terminating ribosome. In this work, the characteristics of mRNA cis-elements inducing the reinitiation process in Escherichia coli have been investigated using a combinatorial approach. A number of novel translational reinitiation sequences (TRSs) were thus identified, which show a wide range of reinitiation activities fully dependent on a translational coupling event and unrelated to the presence/absence of secondary structure or mRNA stability. Moreover, some of the isolated TRSs are similar to intercistronic sequences present in the E. coli genome.

5' Untranslated Regions↗
PubMed2000

Characterization of caveolae from rat heart: localization of postreceptor signal transduction molecules and their rearrangement after norepinephrine stimulation.

Caveolae are plasma membrane subcompartments that have been implicated in signal transduction. In many cellular systems, caveolae are rich in signal transduction molecules such as G proteins and receptor-associated tyrosine kinases. An important structural component of the caveolae is caveolin. Recent evidence show that among the caveolin gene family, caveolin-3 is expressed in skeletal and cardiac muscle and caveolae are present in cardiac myocyte cells. Both the ANP receptor as well as the muscarinic receptor have been localized to the caveolae of cardiac myocytes in culture. These findings prompted us to conduct a further analysis of cardiac caveolae. In order to improve our understanding of the mechanisms of signal transduction regulation in cardiac myocytes, we isolated cardiac caveolae by discontinuous sucrose density gradient centrifugation from rat ventricles and rat neonatal cardiocytes. Our analysis of caveolar content demonstrates that heterotrimeric G proteins, p21ras and receptor-associated tyrosine kinases are concentrated within these structures. We also show that adrenergic stimulation induces an increase in the amount of diverse alpha- and beta-subunits of G proteins, as well as p21ras, in both in vivo and in vitro experimental settings. Our data show that cardiac caveolae are an important site of signal transduction regulation. This finding suggests a potential role for these structures in physiological and pathological states.

Adrenergic alpha-Agonists↗
PubMed2000

Multifocal cerebral hemangio-endothelioma. Case report and review of the literature.

BACKGROUND: Intracranial hemangio-endotheliomas (HE) are rare vascular tumours that present histological features and biological behaviour of an intermediate malignancy. We report the first case of primary HE presenting as multiple intracranial masses. CASE DESCRIPTION: The patient is a 20-year-old female who presented with paresis of the left arm. Magnetic Resonance imaging (MRI) showed multiple lesions in both frontal lobes. Total surgical excision of the tumours was obtained; a histological diagnosis of hemangio-endothelioma was made. Five months later, MRI scan showed new intradiploic skull lesions whereas a scintigraphic study revealed multicentric extracranial bone involvement. Treatment based on interferon-alpha (IFN-alpha) administration was undertaken; this produced partial regression of the lesions. Approximately three years after the first operation, the patient is in good clinical condition. CONCLUSIONS: Surgery continues to play the leading role in the treatment of intracranial HE. However, adjuvant therapy with IFN represents a new and well-tolerated therapeutic method for residual intracranial lesions as well as multicentric extracranial disease.

Adult↗
PubMed2000

Craniovertebral junction malformation and rotational occlusion of the vertebral artery.

An unusual case of rotational occlusion of a non-dominant vertebral artery (VA) is presented. This clinical syndrome is associated for the first time with a complex craniovertebral junction malformation. Rotational occlusion of the VA is usually asymptomatic, vertebro-basilar insufficiency has been rarely observed in cases of involvement of a dominant VA, and concomitant occlusion or hypoplasia of the contralateral artery. Diagnosis of rotational VA occlusion is based on haemodynamic demonstration of the effects of head rotation. The importance of the awareness of this syndrome is stressed.

Atlanto-Occipital Joint↗
PubMed2000

Occipital condylar fractures: a review.

The purpose of this review article is to summarize the epidemiology, pertinent anatomy, mechanisms of injury, and classification systems of occipital condylar fractures (OCFs), as well as their clinical presentation and screening, the importance of computed tomography (CT) for detection, and current treatment options. The authors emphasize the rate of occurrence of OCFs, which may be detected in as many as 16% of patients with craniocervical injury. Clinical presentation is not specific, and OCF is not readily diagnosed at physical examination. Failure to diagnose may result in substantial morbidity, and thus accurate diagnosis is mandatory for both therapeutic and medicolegal implications. The diagnosis is most likely to be made with CT. Thin-section CT technique is the method of choice to evaluate the traumatized craniocervical junction. OCFs should be suspected in all patients sustaining high-energy blunt trauma to the head and/or upper cervical spine, resulting from axial loading, lateral bending and/or rotation, and/or direct blow. Besides a CT study assessing potential intracranial injuries, these patients require CT of the craniocervical junction. Radiologists should be aware of the types of OCFs and associated injuries.

Cervical Vertebrae↗
PubMed1998

Very late cerebral metastasis from malignant melanoma.

The appearance of cerebral metastases of malignant melanoma (MM) more than 10 years after the primary diagnosis is extremely rare. We report the case of a patient with a solitary brain metastasis of MM who came to our observation 11 years after the treatment of the cutaneous lesion. This patient, who up until then had appeared disease free, presented with two episodes of intracranial haemorrhage in a 5-month period. Neuroradiological findings (CT, MRI, angiogram) did not suggest a brain metastasis. The correct diagnosis was reached only after histopathological examination of the surgically removed lesion. On the basis of this experience, we stress the importance of a long-term clinical and radiological follow-up of all patients with MM.

Brain Neoplasms↗
PubMed1996

Hydrocephalus and macrocrania: surgical or non-surgical treatment of postshunting subdural hematoma?

BACKGROUND: Subdural hematoma is a well-known complication of hydrocephalus shunting procedures. Since the advent of modern neuroimaging techniques, a more realistic incidence of subdural hematomas in shunted patients has been recognized. The description of several asymptomatic cases raises the problem of choosing the most appropriate therapeutic policy for such a condition. METHODS: We report two cases with long standing hydrocephalus and macrocrania in which bilateral huge acute and subacute postshunting subdural hematoma developed and remained asymptomatic. RESULTS: The first patient was treated initially by surgery. Subsequently, despite the persistence of the subdural collections, a nonsurgical policy was chosen. The second patient was deliberately nonsurgically treated. CONCLUSIONS: On the basis of our experience, we conclude that a nonsurgical policy should be followed in patients with long standing hydrocephalus and macrocrania, if they develop postshunting large hemorrhagic subdural collections and remain asymptomatic.

Adult↗
PubMed1996

Intracranial epithelioid hemangioendothelioma: case report.

We report the case of a 27-year-old man who underwent surgical excision of an intracranial extra-axial right temporal lesion. A preoperative embolization with the use of a mixture of N-butyl-cyanoacrylate, ultrafluid-lipiodol, and micronized tungsten was necessary to devascularize the tumor. The histological diagnosis was epithelioid hemangioendothelioma. The patient was neurologically intact and tumor-free 18 months after surgery. To our knowledge, this is the fifth patient reported with intracranial epithelioid hemangioendothelioma and the first adult patient for whom complete data are available.

Adult↗
PubMed1996

Cleidocranial dysplasia and syringomyelia. Case report.

cleidocranial dysplasia (CCD) is a dysmorphic syndrome characterized by delayed ossification of the cranial sutures, clavicular hypoplasia and dental dysplasia. We recently observed a 24-year old male patient with CCD and associated syringomyelia and Chiari I malformation (CMI). Only three cases with such an association had been described. The role of posterior fossa bone dysplasia in the pathogenesis of CMI and syringomyelia is discussed.

Adult↗
PubMed1995

Evaluation of fifth nerve dysfunction in 136 patients with middle and posterior cranial fossae tumors.

One-hundred thirty-six patients operated on for extra-axial tumors of the posterior and middle cranial fossae were retrospectively evaluated to define the relevance of trigeminal nerve dysfunction and to correlate clinical and surgical observations. The following data are reported: tumor types, presence of specific trigeminal symptoms and signs, mean duration of symptomatology, anatomical relation between tumor and fifth nerve. Trigeminal symptoms were present in 45 subjects (33.08%) with a mean duration of 23.56 months. Frequency of symptoms was different in various oncotypes. Fifth nerve disturbances were the symptom of onset in 18 subjects (13.23%). A tumoral involvement of the nerve was reported at surgery in 73 patients (53.67%) and was defined as contact, compression or infiltration. Postoperatively, 12 patients showed an improvement of fifth nerve disturbances. A statistically significant difference (p < 0.05) was found in: (1) the incidence of symptoms in patients with and in those without anatomical trigeminal involvement: (2) the incidence of signs in the same groups; (3) the incidence of postoperative relief in patients with fifth nerve compression compared to patients with different surgical findings; (4) the incidence of postoperative relief in patients with typical trigeminal neuralgia compared to those with other symptoms.

Adolescent↗
PubMed1993

Microvascular decompression for trigeminal neuralgia: prognostic factors.

A series of 66 patients with trigeminal neuralgia (TN) treated by microvascular decompression (MVD) is analyzed in order to define the importance of various prognostic factors. A typical pattern of pain, presence of facial hypaesthesia and previous ablative trigeminal procedures showed an unfavorable influence on the results of MVD. Duration of symptoms was longer in patients who failed to benefit from MVD. Pain distribution and the type of vascular compression did not influence the outcome.

Female↗
PubMed1993

Trigeminal involvement in intracranial tumours. Anatomical and clinical observations on 73 patients.

Neoplastic involvement of the trigeminal nerve was observed in 73 patients operated on in our institution for extra-axial tumours of the posterior and middle cranial fossae. It was defined as contact, compression, or infiltration. The nerve root was involved in 58 patients, the ganglion and/or the peripheral divisions in 9, all portions of the Vth nerve system in 6. A clinical trigeminal dysfunction was present in 44 patients (60%). Anatomico-surgical findings are correlated with clinical features and with tumour type. Typical trigeminal neuralgia was the complaint in 7 subjects; all of them presented an involvement of the sensory root. Post-operatively, 11 patients were relieved of their symptoms. The outcome is correlated with the anatomical findings and with the extent of surgical removal of the tumours. The importance of a careful evaluation of patients with trigeminal symptomatology is stressed.

Adolescent↗
PubMed1993

Typical trigeminal neuralgia associated with posterior cranial fossa tumors.

A clinical diagnosis of typical trigeminal neuralgia does not rule out the possibility of a space-occupying lesion compressing the nerve along its course from the brainstem to Meckel's cave. 4 cases of typical trigeminal neuralgia, treated medically for several years and seen here recently before a space-occupying lesion was found in the posterior cranial fossa, point up the need for thorough neurological and neuroradiological examination of all patients with the typical symptoms. Lesion removal resulted in total relief from pain in 3 patients. In the fourth patient the pain was controlled by percutaneous surgery with thermocoagulation of the gasserian ganglion.

Adult↗