Search PubMed⌕ Search

Biomedical subjects

G Maira

Publications and source records attributed to G Maira.

At least 55 records · Page 3Linked to original sources
PubMed1991

Cerebrospinal fluid shunting for hydrocephalus in the adult: factors related to shunt revision.

Cerebrospinal fluid shunting procedures are widely employed in the treatment of hydrocephalus and other disturbances of the dynamics of cerebrospinal fluid. In spite of its popularity, this operation frequently requires surgical revision. A retrospective analysis of a series of 356 adults who underwent the insertion of a cerebrospinal fluid shunt between January 1970 and December 1988 was performed. The incidence of revision was analyzed, and an attempt was made to identify possible causal factors. The overall incidence of surgical revisions was 28.65%; the number of revisions in the same patient ranged between one and eight. The most frequent causes of revision were distal malposition, obstruction, and infection. A statistically significant difference (P less than 0.05) was found in both the risk of revision in patients who had undergone previous operations and those who had not and in the incidence of revision before and after January 1985. Meticulous surgical technique as well as perioperative antibiotic prophylaxis appear responsible for the latter. The differences in the incidence of revision among patients treated with different types of shunts and valves, though remarkable, is not statistically significant.

Adolescent↗
PubMed1991

Post-endarterectomy headache and the role of the oculosympathetic system.

A study was carried out on headache after carotid endarterectomy. A specific type of headache, similar in its characteristics to "cluster headache", occurred on the operative side in 30% of 54 patients, whereas no such headache occurred after extra-intracranial bypass or peripheral vascular surgery. This postoperative headache was not spontaneously reported by 56% of patients unless they were specifically asked about it. Pharmacological pupillary testing performed in 37 patients revealed that a decreased oculosympathetic activity (with or without adrenoceptor supersensitivity) was constantly associated with post-endarterectomy headache. Although this same abnormality was also observed in 54% of the patients without headache, a statistically significant (p less than 0.01) higher prevalence of decreased oculosympathetic responses was found in the patients with headache. The results suggest that damage to the sympathetic plexus due to the surgical procedure is involved in the development of postoperative "cluster-like" headache.

Carotid Artery Thrombosis↗
PubMed1990

Therapeutic possibilities of 131I-MIBG in metastatic carcinoid tumors--preliminary report.

The poor results of traditional therapy in advanced carcinoid tumors and the well-proven uptake of 131I-MIBG shown by some of these tumors induced us to attempt a radiometabolic approach. We selected for the treatment 5 patients (3 men and 2 women) who showed progression of disease, a fairly good uptake of 131I-MIBG with severe related symptoms, and a poor response to traditional therapy. A cumulative radioactivity of 5.5-29.6 GBq was given. Acute side effects after 131I-MIBG administration or late radiation-induced damages were not observed. Symptoms increased during the first 2-4 weeks in 2 patients: in one of these relief was achieved with drugs. Results concerning objective remission of the disease were unsatisfactory. In contrast, definite improvement of symptoms was shown in 2 of 5 patients, resulting in a better quality of life.

3-Iodobenzylguanidine↗
PubMed1990

Hemodynamic effects of decompressive craniectomy in cold induced brain oedema.

An experimental model of cold induced brain oedema was carried out in 7 albino rabbits by topic application of fluid N2 on the skull to examine the favourable effects of an appropriate tailored craniodural opening both on the whole brain perfusion and on the local dynamics of the oedematous fluid. After positioning the animals in a stereotactic frame the following parameters were recorded: ICP, carotid blood pressure and flow velocity, EEG, EKG. Histological staining with Evan's blue was utilized to check fluid extravasation. In all the animals the lesion was followed both by an ICP increase and a reduction in the carotid blood flow velocity so indicating an increase in the cerebrovascular resistances. In 4 animals the removal of the craniodural flap over the lesion dramatically reduced the ICP values and normalized the blood flow velocity. No difference in the Evan's blue distribution was noticed between the two groups of animals.

Animals↗
PubMed1990

Prolactin-secreting adenomas--surgical results.

The long-term follow-up of the transsphenoidal microsurgical treatment in 119 consecutively operated women with a PRL-secreting adenoma is presented. An apparent total removal of the tumor was achieved in 98 cases with an enclosed tumor (58 grade 1 and 40 grade II). In the remaining cases the removal was considered partial. The achievement of persistent normal PRL basal levels was verified in 61 patients (44 grade I and 17 grade II) who had an apparent total removal of the adenoma. In the 37 remaining patients who were thought at surgery to have had total removal we have distinguished two groups: 30 patients showed a "relapse" or "persistence" of PRL levels below 200 ng/ml without clinical and radiological signs of tumor regrowth, and 7 patients with a PRL level higher than 200 ng/ml who had evidence of PRL-secreting tumor recurrence.

Adolescent↗
PubMed1990

Pituitary adenomas in childhood and adolescence.

Pituitary adenomas are considered rare tumors in the pediatric age group. The natural history in this age group is not well known, although many authors have suggested that pituitary adenomas in children tend to be extrasellar and invasive and that a subfrontal approach is mandatory in the majority. Our patients were part of a surgical series of 356 adenomas of all ages. We have divided these cases into three groups: the first consists of patients operated on before the age of 21 years (52 cases, 15%); the second, patients treated after the age of 20 but in whom the clinical history started before 21 years (52 cases, 15%); the third, patients with surgery and symptoms after 20 years (252 cases, 70%). Transsphenoidal removal of the adenomas was the initial procedure in all but one of these cases; a few required a second intracranial operation. In our series, pituitary adenomas in children were not more invasive than in other age groups.

Adenoma↗
PubMed1990

Cerebrospinal fluid pressure and prolactin in empty sella syndrome.

In 58 female patients with the primary empty sella (PES) syndrome, a study of the CSF dynamics was done by evaluating both the absorptive reserve by a lumbar infusion test at constant rate, and/or the ICP increase occurring during REM phase of nocturnal physiological sleep. In 33, prolactin (PRL) dynamics were also investigated evaluating both the response to sequential stimulating test with thyrotropin-releasing hormone (TRH) and metoclopramide (MCP) and/or the circadian variation of PRL levels. Impairment of CSF dynamics was found in the 84% who had a hormonal pattern characterized by an increase of the PRL response to TRH and MCP and a decrease of the PRL circadian variation. Twenty-one patients with impaired CSF dynamics underwent CSF shunting procedures with disappearance of the signs of intracranial hypertension. They also had restoration of normal PRL dynamics but the endocrine alterations improved only moderately. Altered CSF dynamics play a role in the pathogenesis of the PES syndrome. A correlation between elevated ICP and the hypothalamo-hypophyseal control of PRL secretion may exist.

Adult↗
PubMed1990

Paradoxical growth hormone response to thyrotropin-releasing hormone in acromegaly. Clinical correlations and prognostic value.

We have investigated the effect of TRH on the release of GH in 20 acromegalic patients (14 females and 6 males) before and after selective removal of a pituitary tumour via transsphenoidal route. The follow-up period was 8 years. Pre-operatively the paradoxical response was present in 15 patients (75%). Mean GH values in TRH responders were significantly lower than in non-responders. According to the size and expansion diffusion of the adenoma, the patients were divided into 3 classes. The percentage of paradoxical response in patients in class III was significantly lower than in the other two classes. Postoperatively, mean GH values in pre-operative TRH responders were significantly lower than in non-responders; among 15 responders, 13 (86%) had postoperative GH levels under 5 micrograms/l; among 5 non-responders only 2 (40%) had GH values under 5 micrograms/l. Postoperatively 8 patients still had GH responsiveness to TRH: 6 with GH levels persistently (follow-up 8 years) under 5 micrograms/l and 2 with elevated GH values. The other 7 patients, who were responders pre-operatively and non-responders postoperatively, persistently exhibited low GH levels, except one subject who showed an increase in GH levels with reappearance of the paradoxical response, two years after surgery. These results suggest: 1. the paradoxical response may be expressed only when the hypothalamus-pituitary interactions are intact; 2. the disappearance of the paradoxical response cannot surely suggest a remission, and 3. the presence of a pre-operative paradoxical response is a good prognostic feature.

Acromegaly↗
PubMed1989

New tracers for the imaging of the medullary thyroid carcinoma.

I-MIBG and 99Tcm(V)-DMSA have been recently proposed as scintigraphic markers of the medullary thyroid carcinoma (MTC). Thirty two patients were examined with 131I- or 123I-MIBG and 26 of these were re-examined with 99Tcm(V)-DMSA (planar and SPECT). From our experience we can draw the following conclusions: (1) the scintigraphic attempt was useless in patients with normal levels of plasma calcitonin (CT): (2) in patients with high plasma CT levels, the sensitivity of the MIBG was better in familiar (3/3 true positive) than in sporadic disease (7/21 true positive; overall sensitivity = 42%); the 99Tcm(V)-DMSA was positive in 16/19 cases, (overall sensitivity = 84%) even in cases which had been false negative with MIBG (6 patients); (3) no false positive results were found; (4) the scan with 99Tcm(V)-DMSA is then suggested as the first imaging approach during the follow up in patients affected by MTC and still having high levels of plasma CT. The MIBG scan should be limited to the patients in whom the possible use of MIBG therapy has to be investigated.

3-Iodobenzylguanidine↗
PubMed1989

Prolactin-secreting adenomas: surgical results and long-term follow-up.

Transsphenoidal surgery is an efficacious treatment for patients with prolactin (PRL)-secreting adenomas, even if disrupted pituitary-hypothalamic relationships may persist and/or a recurrence of the PRL-secreting tumor can occur. In this paper, we analyze the long-term follow-up of 119 consecutively treated women who underwent transsphenoidal microsurgery for PRL-secreting adenomas. Apparent total removal of the tumor was achieved in 98 patients who had enclosed tumors (58 with Grade-I tumors and 40 with Grade II). In the remaining patients, the removal was considered partial. Persistent normal basal PRL levels were achieved in 61 patients who had apparent total removal of the adenoma (44 with Grade I tumors and 17 with Grade II). Of the remaining 37 patients in whom surgical removal of the adenomatous tissue was thought to be total, 30 had persistent nonevolutive, high PRL levels ranging from 21 to 196 ng/ml, without clinical and radiological signs of tumor regrowth, and 7 with PRL levels ranging from 56 to 560 ng/ml had a recurrence of the PRL-secreting tumor. These data seem to indicate that a slightly elevated postsurgical PRL value does not imply that tumoral tissue is still present. Nontumoral conditions (i.e., a secondary empty sella) could induce functional hyperprolactinemia.

Adenoma↗
PubMed1988

One year follow-up of patients clinically preselected for excessive risk of stroke.

From a consecutive series of 812 patients at risk of stroke we selected 100 who seemed to be at high risk (excessive stroke risk--ESR) on the following clinical criteria: either multiple reversible ischemic attacks in one carotid territory or multiple (or bilateral) severe stenotic carotid lesions. The patients of the first subgroup received medical therapy and those of the second were referred for surgery. The 100 patients were followed up for 12 months, during which 29 patients had cerebral ischemic events: 17 having stroke and 12 TIA. This study suggests that it is possible to identify beforehand subgroups of ESR patients, thereby facilitating the selection of patients for brain protection and avoiding huge trials of unselected cerebrovascular patients.

Aged↗
PubMed1988

Effect of fentanyl-oxygen anesthesia during cardiac surgery on serum thyroid hormones.

Twenty-five euthyroid patients who underwent cardiac surgery with fentanyl-oxygen anesthesia were studied. The authors confirm that some thyroid hormones undoubtedly take part in a non-specific pool of reactions caused by surgical stress. For one or more days, all the patients had total triiodothyronine (TT3) and free triiodothyronine (FT3) levels clearly below the normal values, with a parallel increase in reverse triiodothyronine (rT3, biologically inactive). Changes in total (TT4) and free thyroxine (FT4), although significant, were smaller and hard to interpret. The most important changes occurred on the first postoperative day. Of seven patients who before the operation had a TT3 value below the lower normal limit, six had at discharge a mean TT3 level significantly above it. Serum TT3 concentrations could be a reliable prognostic index. High-dose fentanyl anesthesia probably does not affect thyroid hormone response to surgical stress. To date, the mechanisms which cause reduction of serum triiodothyronine have not been fully discovered and it is not known for certain whether this reduction is beneficial to the human organism.

Adult↗
PubMed1987

Neurological improvement in chronic ischemic stroke following surgical brain revascularization.

50 patients suffering from completed ischemic stroke in the carotid territory for at least two months (17 mild, 31 moderate, 2 severe strokes) underwent extra-intracranial arterial bypass surgery. Neurological improvement was obtained in 43 cases; it persisted in time in 40 cases. Quantitative evaluation of motor performance in 21 patients showed that the degree of improvement was highly significant. Several factors strongly indicate a causal relation between surgical revascularization and neurological restoration. The positive surgical result is strictly dependent on correct patient selection and, in particular: i) on the documentation of local hemodynamic insufficiency; ii) on the occurrence of transient neurological (and to a certain extent EEG) improvement following hyperbaric oxygenation. The latter can also provide reliable information on the minimum degree of improvement to be expected from surgery.

Adolescent↗
PubMed1987

Vasoconstriction of the basilar artery in rabbits: the vasoconstrictor activity of blood, CSF and blood-CSF mixtures incubated for varying periods of time.

After subarachnoid haemorrhage, the amount of blood in the subarachnoid space and the time elapsed since the haemorrhage seem important factors in predicting the occurrence of vasospasm. In this experiment we studied the responses of the rabbit basilar artery to acute topical application of samples of human cerebrospinal fluid (CSF), mixtures of blood and CSF incubated at 37 degrees C for 0 to 12 days. The degree and the duration of the vasoconstriction depended on the time of incubation and on the concentration of blood in the samples. Samples incubated for five and seven days caused severe and long-lasting vasoconstrictions. Samples incubated for 0, 1, 3, 8, 10 and 12 days caused slight or moderate and short-lasting vasoconstriction. Samples incubated for 5, 7, 8, and 10 days showed a linear relationship between the concentration of blood and the degree of constriction up to the blood-CSF ratio of 0.6 to 1 (blood content of 37.5%); further increases of blood concentration did not cause further vasoconstriction. This phenomenon may be related to the saturation of arterial receptors. The course of the vasoconstriction using samples with different blood concentrations suggests the existence of more vasoactive substances. This work seems to confirm the importance of blood concentration in the CSF and of time as factors governing the development of vasospasm.

Animals↗
PubMed1987

Intracranial pressure behaviour and its relation to the outcome of surgical CSF shunting in normotensive hydrocephalus.

Twenty-four patients with suspected normotensive hydrocephalus were surgically treated by cerebrospinal fluid (CSF) ventriculoatrial or peritoneal shunt. The results of surgery were considered in relation to clinical history and different diagnostic examinations: pneumoencephalography, CT scan, isotope cisternography, transfer from CSF to blood of isotope-labelled serum albumin, constant infusion manometric test, intraventricular pressure recording. Intracranial pressure (ICP) was analysed during both resting conditions and spontaneously (REM phase of sleep) or artificially induced (jugular compression) increases. The ventricular enlargement (as shown by CT scan) and the slope of the intracranial elastance (the ratio of the differences between the maximum and minimum values of pulse ICP and the correspondent values of the diastolic ICP under the same dynamic conditions) provided the most reliable data for diagnosis and surgical prognosis.

Cerebrospinal Fluid Shunts↗
PubMed1987

Prolactin dynamics in normoprolactinemic primary empty sella: correlation with intracranial pressure.

Prolactin dynamic was investigated in 43 premenopausal patients with primary empty sella (PES) diagnosed by pneumoencephalography and CT scan. Only normoprolactinemic patients were included in this study. Basal PRL levels ranged from 4 to 25 ng/ml. PRL responses to TRH (200 micrograms i.v.) and metoclopramide (MCP, 10 mg p.o.) were not significantly different from those in normal subjects, although a trend toward higher responses was present in PES patients. The administration of nomifensine (NOM, 200 mg p.o.) induced a PRL decrease, which was not significantly different from that in normal subjects. However, a sequential stimulation with TRH plus MCP (1 h after TRH administration) induced an exaggerated PRL increase which was significantly different from that in normal subjects. The peak PRL responses after stimulation were not significantly correlated with estradiol levels or FSH/LH ratios in our patients. The influence of body weight was also excluded on the basis of the responses observed in 8 obese control subjects that were significantly lower than in PES patients. Moreover, in 19 patients we studied the intracranial pressure (ICP) through an indwelling catheter inserted into the lumbar subarachnoid space. ICP was normal in 5 patients and elevated in 14 patients. When we compared PRL dynamics in patients with normal or elevated ICP, a significant difference was noted between the percentage of PRL decrease after NOM, that was lower and delayed in patients with increased ICP, suggesting an influence of ICP on neuronal dopamine reuptake. In conclusion, an augmented PRL reserve is present in premenopausal patients with PES. A correlation can be found between ICP and the function of dopaminergic neurons controlling lactotroph cells.

Adult↗
PubMed1986

Total excision of spinal lipomas using CO2 laser at low power. Experimental and clinical observations.

Total excision of spinal lipomas (SL) is difficult because of the intimate adhesion between the fibro-adipose tissue and the neural structures. Radical surgery in SL can provoke nervous lesions; therefore many authors recommend only partial excision as a means of decompression. Nevertheless the role of traction or tethering of the spinal cord in all spinal disraphism, including SL, is known to be very important in determining the clinical picture. So partial removal of SL cannot be effective in releasing the tethered cord. The use of a CO2 laser at low power (3-5 W) permitted radical surgery without any neural damage and complications in 2 adult patients with large, not well capsulated SL. These patients were previously operated on by the same surgeon with conventional microsurgical techniques for partial excision. After CO2 laser surgery there was significant improvement of the clinical pictures, the follow-up being respectively 24 and 36 months. This clinical experience was performed after a CO2 laser had successfully been used in an experimental model in rats simulating a condition of SL. Using power of 3-5 W was not sufficient to attain an immediate vaporization, but the adipose tissue first changed into a transparent liquid across which it was possible to recognize the interfaces between the neural structures and the adipose tissue.

Adult↗