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Biomedical subjects

M Rollo

Publications and source records attributed to M Rollo.

At least 19 recordsLinked to original sources
PubMed2003

Characterisation of intestinal peptide transporter of the Antarctic haemoglobinless teleost Chionodraco hamatus.

H(+)/peptide cotransport was studied in brush-border membrane vesicles (BBMV) from the intestine of the haemoglobinless Antarctic teleost Chionodraco hamatus by monitoring peptide-dependent intravesicular acidification with the pH-sensitive dye Acridine Orange. Diethylpyrocarbonate-inhibited intravesicular acidification was specifically achieved in the presence of extravesicular glycyl-L-proline (Gly-L-Pro) as well as of glycyl-L-alanine (Gly-L-Ala) and D-phenylalanyl-L-alanine (D-Phe-L-Ala). H(+)/Gly-L-Pro cotransport displayed saturable kinetics, involving a single carrier system with an apparent substrate affinity (K(m,app)) of 0.806+/-0.161 mmol l(-1). Using degenerated primers from eel and human (PepT1) transporter sequence, a reverse transcription-polymerase chain reaction (RT-PCR) signal was detected in C. hamatus intestine. RT-PCR paralleled kinetic analysis, confirming the hypothesis of the existence of a PepT1-type transport system in the brush-border membranes of icefish intestine. Functional expression of H(+)/peptide cotransport was successfully performed in Xenopus laevis oocytes after injection of poly(A)(+) RNA (mRNA) isolated from icefish intestinal mucosa. Injection of mRNA stimulated D-Phe-L-Ala uptake in a dose-dependent manner and an excess of glycyl-L-glutamine inhibited this transport. H(+)/peptide cotransport in the Antarctic teleost BBMV exhibited a marked difference in temperature optimum with respect to the temperate teleost Anguilla anguilla, the maximal activity rate occurring at approximately 0 degrees C for the former and 25 degrees C for the latter. Temperature dependence of icefish and eel intestinal mRNA-stimulated uptake in the heterologous system (oocytes) was comparable.

Amino Acid Sequence↗
PubMed2001

Spinal cord stimulation and early experimental cerebral spasm: the "functional monitoring" and the "preventing effect".

BACKGROUND: Clinical and experimental data on cerebral blood flow (CBF) changes during spinal cord stimulation (SCS) were published since 1986. The aims of the present work are: 1. To find an experimental model of reliable, simple and in vivo monitoring of "early" basilar artery spasm after subarachnoid haemorrhage (SAH) and 2. To investigate the effects of cervical spinal cord stimulation (CSCS) on it. Vasospasm due to SAH is both "acute" and "recurrent". Early spasm occurs within minutes of the SAH. its duration is approximately 1 hour. The need of different morphological and haemodynamic methods to evaluate experimental early spasm is reported. To overcome intracranial surgical manipulations and biological effects of contrast and fixation media we designed a model that allows "in vivo" functional monitoring of basilar blood flow far away from the spasm without direct surgical and chemical interference. Subsequently we investigated the effects of CSCS on the new model of "functional monitoring" of the "early" cerebral vasospasm. METHOD: 29 adult Burgundy rabbits were studied. Group 1: under homeostatic monitoring, "on-line" carotid blood flow (carotid BF) changes produced by SAH in cisterna magna of 12 (plus 5 sham treated) animals were studied from the common carotid artery after external carotid artery occlusion before, during SAH and up to the end of the experiments. All the animals underwent digital subtraction cerebral panangiography (CPA) after SAH obtaining a significant increase of carotid BF only when basilar vasospasm was shown by CPA. Carotid BF increase during basilar vasospasm was defined "functional monitoring" of early spasm. Group 2: Twelve animals wearing a cervical epidural electrode underwent carotid BF "functional monitoring" of early basilar spasm before and during CSCS. FINDINGS: Carotid BF changes during CSCS occurred in 10 animals. No carotid BF changes (i.e. no basilar vasospasm) occurred after SAH up to the end of the experiments in all the stimulated animals. INTERPRETATION: CSCS is able to prevent "early spasm" due to SAH in all the animals studied with the new model of "functional monitoring" described, independently from the occurence and the sign for stimulation-induced carotid BF variations. The role and the limits of reversible functional sympathectomy in mediating the effect of CSCS on early vasospam are discussed.

Acute Disease↗
PubMed2001

Deletion of the alpha(1,3)galactosyl transferase (GGTA1) gene and the prion protein (PrP) gene in sheep.

Nuclear transfer offers a cell-based route for producing precise genetic modifications in a range of animal species. Using sheep, we report reproducible targeted gene deletion at two independent loci in fetal fibro-blasts. Vital regions were deleted from the alpha(1,3)galactosyl transferase (GGTA1) gene, which may account for the hyperacute rejection of xenografted organs, and from the prion protein (PrP) gene, which is directly associated with spongiform encephalopathies in humans and animals. Reconstructed embryos were prepared using cultures of targeted or nontargeted donor cells. Eight pregnancies were maintained to term and four PrP-/+ lambs were born. Although three of these perished soon after birth, one survived for 12 days. These data show that lambs carrying targeted gene deletions can be generated by nuclear transfer.

Animals↗
PubMed2001

Carbonic anhydrase activity in tissues of the icefish Chionodraco hamatus and of the red-blooded teleosts Trematomus bernacchii and Anguilla anguilla.

Carbonic anhydrase (CA) activity was measured in blood, intestine, kidney and gill of two Antarctic teleosts, the haemoglobinless Chionodraco hamatus and the red-blooded Trematomus bernacchii, and of the temperate teleost Anguilla anguilla. In all species, the highest CA activity was in the gills, with the greatest activity in C. hamatus. CA activity in the blood was highest in A. anguilla, but none was detected in the blood of C. hamatus despite the presence of plasma CA inhibitors. The enzyme was present but its activity was low in the intestine and kidney of all three species. The existence of very high CA activity in C. hamatus gills compared with the red-blooded species was investigated further by isolating and characterising the branchial cytosolic CA isoforms. The turnover rate of the C. hamatus isoform was significantly higher than that of T. bernacchii and A. anguilla. The isoforms from both the Antarctic species exhibited lower apparent K(m) (K(m,app)) and heat stability than those from A. anguilla. Sensitivity to sulphonamides was similar in all species and was within the range of the mammalian CA II isoform. The branchial CA isoforms of C. hamatus, T. bernacchii and A. anguilla displayed relative molecular masses of 28.9, 29.9 and 31.2 kDa, respectively. The results suggest that the hemoglobinless teleost possesses a different branchial cytosolic CA isoform from that of red-blooded teleosts.

Anguilla↗
PubMed2000

Cerebral arteriovenous malformations in children.

In spite of their congenital origin, only 18-20% of cerebral AVMs are diagnosed during infancy and childhood. Intracranial haemorrhage is the presenting clinical manifestation in 75-80% of paediatric patients and is associated with a high morbidity and mortality. The natural history of untreated cerebral AVMs in children is worse than in adults, in relation to a longer life expectation, a higher annual risk of AVM bleeding (3.2% vs. 2.2%) and a higher incidence of posterior fossa and basal ganglia AVMs, most of which present with massive haemorrhages. The surgical excision remains the treatment of choice for parenchymal AVMs in children; AVM complete removal is currently achieved in 70-90% of the patients. With the advent of new agents for endovascular management, preoperative AVM embolization has further improved surgical results. Stereotactic radiosurgery appears to be a successful treatment option in small or moderate sized AVMs. Recent studies have demonstrated low complication rates with this technique in paediatric patients. We reviewed our experience with 37 paediatric AVMs treated at the Section of Paediatric Neurosurgery of the Catholic University of Rome between 1980 and 1997. Twenty-three patients underwent surgery as the only treatment modality; endovascular embolization was combined with the surgical treatment in a further four cases. Radiosurgery was utilized as the only treatment in three patients and in combination with other techniques in an other three children (with surgery in one case and with AVM embolization in the remaining two subjects). No treatment was carried out in three patients because of excessively critical condition on admission; endovascular embolization failed in a further patient because of the anatomical complexity of the malformation. Previous studies have demonstrated a quite strict correlation between AVM complexity based on Spetzler and Martin's grading system and patients outcome. A less direct relationship has been observed in the present study. In our experience the factors which were more closely predictive of patients' outcome were the occurrence of an AVM bleeding and the neurological status on admission. In spite of the low number of cases in the single subsets of patients this study seems to support the role of AVM embolization and radiosurgery as effective adjuvant techniques in the management of cerebral AVMs in children.

Adolescent↗
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↗
PubMed1999

Injury of the vertebral artery after closed head trauma.

Two case reports characterized by the complete occlusion of the basilar artery, secondary to dissection of the vertebral artery after closed head trauma are described. These lesions, often clinically silent in the beginning, were able to cause severe neurologic impairment, even after minor head trauma in healthy individuals without predisposing structural disorders. Early detection, based upon the knowledge of the modality of the trauma and upon a correct diagnostic approach, is mandatory to reduce secondary injury. The authors suggest an extensive use of cerebral angiography or angio-magnetic resonance in all cases where clinical conditions are more severe than the computed tomography scan, particularly if the trauma produced a cervical injury with a movement of flexo-extension of the neck. Therapeutic management is discussed. Anti-coagulants, thrombolytic agents or surgical ligation of the vessel has been proposed to prevent the extension of the lesion and to improve the outcome.

Adult↗
PubMed1998

Body composition and energy expenditure of patients with chronic cardiac failure.

BACKGROUND: Patients with acute cardiac failure have excess body water, and it is commonly assumed that this is also so in patients with stable chronic cardiac failure (CCF). METHODS: To investigate this, we measured total body water (TBW) using stable isotope dilution and single-frequency bioelectrical impedance (BIA), and also extracellular volume (ECV) using bromide dilution in 12 patients with CCF and eight matched control subjects. RESULTS: TBW [kg(-1) bodyweight] was similar in the two groups [median 18O dilution 53.2% (range 46.5-57.1%) in patients vs. 54.8% (47.9-62.7) in control subjects; BIA 56.6% (42.7-73.1) vs. 58.0% (52.0-68.6)]. ECV was also similar in the two groups [0.25 Lkg(-1) (0.20-0.29) vs. 0.25 (0.19-0.35)]. There was a strong correlation between stable isotope and BIA measurements of TBW for all subjects (r = 0.76), but BIA overestimated TBW by a mean difference of 2.4 kg (limits of agreement of -4.1 kg to +8.9 kg). Body fat content was similar in the two groups, whether measured by skinfold anthropometry, whole-body densitometry or by 18O dilution. Resting energy expenditure (REE), calculated from indirect calorimetry, and total energy expenditure (TEE), calculated from the ratio of 2H to 18O elimination rate after drinking doubly labelled water, were also similar in the two groups. CONCLUSION: It is concluded that the patients with stable CCF in this study had normal ECV and TBW, and so excess body water did not account for their persistent symptoms.

Aged↗
PubMed1997

Combined management of intracranial vascular malformations in children.

UNLABELLED: We have reviewed 39 cases of intracranial vascular malformations, observed in the Section of Paediatric Neurosurgery of the Catholic University of Rome between 1980 and 1995 (age 1-15 years). Diagnosis was of parenchimal AVM in 26 cases, in 7 cases of AVM of the Galen region, in 5 cases of dural AVM and in 1 case of venous angioma. RESULTS AND CONCLUSIONS: Haemorrhage was the prevalent clinical onset in patients with parenchimal AVMs (57.7% of cases). Only one patient with a Galen region AVM presented cardiovascular symptoms, while 2/5 children observed for a dural AVM complained a congestive heart failure. Total surgical excision was performed in 17 of the 26 patients with parenchimal AVMs; moreover surgery was combined with preoperative endovascular embolization in 2 cases and with radiosurgery in 1 patient; we think that surgery is still the treatment of choice in patients with parenchimal AVMs. Endovascular treatment and radiosurgery have mainly an adjuvant role; nevertheless we agree that a preoperative endovascular management of parenchimal AVMs reduces the surgical risk, especially in cases of huge AVMs or AVMs localized in eloquent areas of the brain. Radiosurgery may be an alternative choice for complex or deeply sited AVMs; however in most cases, a combination with surgery or endovascular treatment is necessary to reduce the "target" size. AVM embolization was the only treatment in 2 of the 6 cases of dural AVMs; dural AVM embolization was combined with surgery in 1 case. Endovascular AVM exclusion is the treatment of choice in these patients. Surgery may be combined with endovascular treatment in case of a partial persistence of the AVM, or if signs of revascularization are present on control angiography. A conservative management is justified in patients with carotido-cavernous fistulae; in fact a complete spontaneous thrombosis is very frequent in these cases. A high rate of cardiovascular symptoms is reported in patients with Galen region AVMs diagnosed in the 1st year of life, but only 1 of our patients complained of congestive cardiac symptoms. Surgical treatment of Galen region AVMs is associated with a high morbidity and mortality. Actually a transarterial embolization of afferent vessels represents the treatment of choice in these patients; it can be combined with transvenous approach in case of complex AVMs and/or a non complete AVM exclusion.

Adolescent↗
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

Diagnosis of traumatic carotid-cavernous sinus fistula by monitoring venous oxygen saturation in the jugular bulb: report of two cases.

OBJECTIVE AND IMPORTANCE: A traumatic carotid-cavernous sinus fistula (CCF) is rarely diagnosed early and may sometimes be missed until clinical signs and symptoms appear. The continuous monitoring of cerebral venous oxygen saturation may reveal the presence of a CCF by means of a fiberoptic catheter that records very high oxygen saturation values when positioned in the jugular bulb. CLINICAL PRESENTATION: We report two cases of early diagnosis of CCFs unexpectedly revealed by monitoring the jugular bulb for venous oxygen saturation values that approximated arterial saturation values. One case was diagnosed on Day 3 after admission, and the other was diagnosed shortly after cannulation of the ipsilateral jugular bulb. INTERVENTION: Confirmation of the diagnosis of CCF was obtained by angiography. Intravascular treatment was performed in one case. CONCLUSION: These cases add another diagnostic role to cerebral venous oxygen saturation monitoring. When high cerebral venous oxygen saturation values rapidly or abruptly reach arterial oxygen saturation, the presence of a CCF must be considered and confirmed by arterial angiography.

Adolescent↗
PubMed1996

[Diagnostic impact of ultrasonography in abdominal diseases].

The diagnostic accuracy of conventional radiography and ultrasound (US) in patients with acute or chronic abdominal pain was investigated by the authors in two prospective studies to assess the capabilities of the two imaging techniques. 262 patients (135 men and 127 women, age range: 25-83 years) were entered into the study within 8 months. The patients were divided into different groups according to clinical presentation (80 patients with acute and 182 with chronic pain) and to the referring physician (a hospital clinician for 127 patients and a general practitioner for 135 patients). For each technique the presence (positive result) or the absence (negative result) of abnormal imaging features related to clinical symptoms was recorded and the agreement of conventional radiography and US findings was assessed. Statistical analysis showed similar sensitivity of conventional radiography and US in the examination of acute hospitalized patients (54.3% positive results), chronic hospitalized patients (28.1% negative results) and chronic nonhospitalized patients (47.2% negative results). The results of our prospective studies showed poor diagnostic accuracy of the two techniques and clearly evidenced the improper use of diagnostic imaging methods by referring physicians, with a technical-oriented attitude in imaging examination requests. In the authors' opinion, a clinical-based approach by referring physicians with accurate patient selection might improve diagnostic accuracy, the cost/benefit ratio and the clinical effectiveness of imaging techniques.

Abdominal Pain↗
PubMed1995

Cyclospora in AIDS patients: not always an agent of diarrhoic syndrome.

The present study reports the clinical features of two AIDS patients infected by Cyclospora. According to our observations, Cyclospora in AIDS can be responsible both for gastroenteritis and for asymptomatic infections with spontaneous rapid clearance. In addition, and undiagnosed circulation of this agent in Italy could be hypothesized: neither patient had a past history of foreign travel. These are the first two cases in AIDS described in Italy.

AIDS-Related Opportunistic Infections↗
PubMed1995

[Transitory swelling of a parotid gland following general anesthesia. Description of a case].

An acute transient swelling of the parotid glands is recorded after general anaesthesia in orthopaedic surgery. The first differential diagnosis is bacterial parotitis; other causes of gland enlargement are viral infections, lymphoma, leukemia, sarcoidosis, Sjogren's syndrome, malnutrition cirrhosis, vomiting, and poor oral hygiene. Excluding the above mentioned conditions, the most probably factors involved in our case are drugs used for anaesthesia, congestion of the venous drainage of the gland because of parasympathetic stimula during tracheal intubation and head positioning during surgery.

Acute Disease↗