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Biomedical subjects

P Guerra

Publications and source records attributed to P Guerra.

At least 37 records · Page 2Linked to original sources
PubMed1994

Somatomedin C (insulin-like growth factor 1) levels decrease during acute changes of stress related hormones. Relevance for fibromyalgia.

OBJECTIVE: To determine the effects of stress hormones on insulin-like growth factor 1 (IGF-1). METHODS: Insulin induced hypoglycemia (< 3 mmol/l) and clonidine induced depression of noradrenergic tone were used to assess the acute effects of cortisol, human growth hormone (hGH), and norepinephrine (NE). RESULTS: Despite the increase of hGH during hypoglycemia, a statistically significant decrease of IGF-1 was observed along with the expected rise of cortisol and NE. To eliminate the role played by NE, NE tone was depressed by administering clonidine. A statistically significant decrease of IGF-1 was also observed. CONCLUSION: Acute cortisol release or a NE decrease induce low IGF-1 levels.

Clonidine↗
PubMed1992

Primary traumatic benign midbrain haematoma in hyperextension injuries of the head.

Primary traumatic brain stem injury occurring in isolation is not universally recognized as a distinct pathological entity which may follow a head injury. We describe two patients with clinical and radiological evidence of primary posttraumatic midbrain haemorrhage occurring in isolation associated with good recoveries. It is suggested that paramedian midbrain syndromes associated with midbrain haemorrhages should be recognized as a distinct, although unusual, complication of hyperextension injury to the head which may have a benign course.

Adult↗
PubMed1992

Sympathetic nervous system in high sodium one-kidney, figure-8 renal hypertension.

The contribution of the sympathetic nervous system and vasopressin to the maintenance of arterial pressure was investigated in high sodium-fed rats 4 weeks after the induction of one-kidney, figure-8 renal wrap hypertension. Arterial pressure was significantly greater in renal-wrapped rats than in sham-operated animals. The contribution of the sympathetic nervous system was assessed functionally by measuring the arterial pressure response to ganglionic blockade and estimating the apparent rate of release of norepinephrine. The contribution of vasopressin was assessed by administration of the vascular antagonist d(CH2)5Tyr(Me)-AVP. Whole-animal vascular responsiveness and cardiac baroreceptor reflex sensitivity were determined by graded intravenous bolus injections of angiotensin II, vasopressin, and phenylephrine. Hypertensive rats demonstrated an exaggerated reduction in arterial pressure to autonomic blockade before and after blockade of vascular vasopressin receptors. There was a significant 27% increase in the apparent rate of release of norepinephrine into the plasma. Administration of d(CH2)5Tyr(Me)-AVP did not affect arterial pressure when given alone. However, after ganglionic blockade, inhibition of the vasopressin system elicited similar falls in blood pressure in both normotensive and hypertensive rats. Arterial pressure dose-response effects of phenylephrine, angiotensin II, and vasopressin were similar between renal-wrapped and sham-operated animals; however, cardiac baroreceptor reflex sensitivity was suppressed in the hypertensive rats. These studies indicate that the maintenance of arterial pressure in chronic, high sodium renal-wrap hypertension is associated with an augmented sympathetic nervous system function.

Animals↗
PubMed1991

Treatment of advanced neuroblastoma with I-131 meta-iodobenzylguanidine.

From February 1986 to December 1988, 31 children with advanced pretreated neuroblastoma were treated with 131-I meta-Iodobenzylguanidine (131-MIBG). Thirteen children had been resistant to first-line therapy, three had suffered a local relapse, and fourteen had suffered a disseminated relapse without over bone marrow infiltration. One child was treated initially because of resistance to first-line therapy, and subsequently for a local relapse. A total of 72 courses of 131-MIBG was administered, with doses ranging from 2.8 to 6.0 GBq (median, 3.7 GBq). One child received five courses, two four courses, 13 three courses, four two courses, and 12 one course of 131-MIBG. The most common toxic effect was thrombocytopenia, with a platelet level of less than 50,000/cmm occurring after 19 of 60 evaluable courses. A leukocyte count less than 1000/cmm was seen only once. There were six major responses (two complete) lasting 4 to 9 months, and two minor responses lasting longer than 38 and 44 months. Responses were seen more commonly in children whose only lesion was a residual primary tumor and in children who had not been pretreated who experienced disseminated relapse. Further studies of the role of 131-I meta-Iodobenzylguanidine in treatment of neuroblastoma are needed.

3-Iodobenzylguanidine↗
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

Effect of nifedipine in arterial vasculature of human placenta.

1. Nifedipine induced concentration-dependent relaxations in segments of human placental arteries precontracted with 40 mM K+. 2. Preincubation of segments with nifedipine induced concentration-dependent inhibition of contractions elicited by 40 mM K+ (IC50, 2.5 x 10(-9) M) and 10(-7) M 5-HT (5.9 x 10(-8) M). 3. The time-course of contractions elicited by K+ and 5-HT (responses not sustained) in the absence and in the presence of nifedipine was different. 4. Nifedipine inhibited Ca addition-evoked contractions in Ca-free medium containing 40 mM K+ or 10(-7) M 5-HT, mainly those obtained in depolarized segments. 5. These results indicate that these arteries are very sensitive to nifedipine and that the voltage-operated Ca channels are more affected by the Ca antagonist than receptor-operated ones.

Arteries↗
PubMed1990

Interference of diltiazem with serotonin- and potassium-induced contractions in human placental veins.

1. In segments of human placental veins precontracted with K+ (25, 40 or 75 mM), diltiazem produced concentration-dependent relaxations with similar EC50 values. 2. Diltiazem (20 min preincubations) also caused concentration-dependent inhibition of the contractions induced by K+ (40 or 75 mM) and 5-HT (serotonin, 3 x 10(-7) M). IC50 values were similar, in both cases. 3. The time-course of the vasocontractions induced by 75 mM K+ and 3 x 10(-7) M 5-HT in the absence and in the presence of diltiazem were different. The contractions caused by K+ were sustained and transient those elicited by 5-HT. 4. These data suggest that (1) this vasculature is sensitive to diltiazem, and (2) the Ca influx through voltage-operated Ca channels (activated by K+) and through receptor-operated Ca channels (activated by 5-HT) is very similar.

Diltiazem↗
PubMed1990

Effects of Ca2+ antagonists nifedipine and diltiazem on isolated human chorionic arteries and veins.

5-Hydroxytryptamine (5-HT) and K+ induced contractions in human chorionic arteries and veins. 5-HT-caused responses were blocked by ketanserin (10(-7) and 10(-6) M) and prazosin (10(-5) but not 10(-6) M). K(+)-induced contractions were practically abolished in a Ca2(+)-free medium, whereas those produced by 5-HT were reduced. The efficacy (EC50 values) of diltiazem to produce relaxation in arteries and veins contracted with 40 or 75 mM K+ was similar, but normally greater than that of nifedipine. The potency of nifedipine (IC50 values) to inhibit maximal K+ contractions was greater than to inhibit maximal 5-HT contractions; diltiazem showed an inverse order of potency, which was less than that of nifedipine. The time course of 10(-6) M 5-HT and 75 mM K+ contractions was different, as much in the absence as in the presence of both Ca2+ antagonists; 5-HT contractions were transient, but sustained those elicited by K+. K+ (75 mM) and 5-HT (10(-6) M) produced increases in 45Ca2+ uptake, which were reduced by the Ca2+ antagonists. These results indicate that (a) human chorionic arteries and veins are similarly sensitive to Ca2+ antagonists, (b) 5-HT-induced contractions were largely dependent on extracellular Ca2+ and mainly mediated by 5-HT2 receptors but not by alpha 1-adrenoceptors, and (c) nifedipine was more potent than diltiazem in inhibiting Ca2+ influx through potential- and receptor-dependent Ca2+ channels.

Arteries↗
PubMed1989

Clinicoradiological and therapeutic considerations in severe diffuse traumatic brain injury in children.

Forty-one children with severe head injuries and diffuse brain lesions were selected from a consecutive series of 62 children in traumatic coma (21 focal mass lesions) and studied. According to the CT pattern, two main types of intracranial lesions were considered: diffuse axonal injury (DAI) and diffuse brain swelling (DBS). High mortality, due to secondary increases of intracranial pressure (ICP), correlated well with the patterns of severe DBS, absence of perimesencephalic cisterns, and obliteration of the ventricles. However, children with normal CTs, and/or obvious shearing injuries indicative of DAI, had favorable outcomes; there was no mortality if increased ICP was not present. We conclude that although there does not seem to be any routine indications for ICP monitoring in children with pure DAI, early ICP monitoring and aggressive management of increasing ICP should be considered in comatose children with DBS, especially when associated with subarachnoid hemorrhage and respiratory or circulatory failure.

Adolescent↗
PubMed1989

[Diffuse traumatic cerebral injuries in children].

A consecutive series of 41 patients aged less than 16 and admitted to the Department of Neurosurgery of the University of Milan in the period 1977-1978 following serious cranioencephalic trauma with Glasgow Coma Score (GCS) less than or equal to 7, duration of coma longer than 24 h and CT picture of diffuse lesion has been examined. These patients account for 5% of the paediatric cranial traumas observed in the same period and 66% of those in a state of coma. The CT picture made it possible to split patients into 3 groups: a) those without visible cerebral lesions and with subarachnoid and cisternal spaces present; b) those with small hyperdense lesions due to intraparenchymal or median/paramedian subcortical shearing lesions; c) those with marked constriction or absence of the 3rd ventricle and of the perimesencephalic cisterns. The first two pictures (a, b) were considered to be the expression of diffuse axonal damage, the last (c) of diffuse cerebral swelling. Intracranial pressure was monitored in about 50% of patients. The overall outcome of the series was favourable in more than 68% of cases with total mortality of 26.8%. Analysis of individual tomographic categories, however, showed that whereas the group of patients with diffuse axonal lesion presented nil mortality, those with diffuse cerebral swelling had 52% mortality owing to the onset of refractory intracranial hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Treatment of neuroblastoma with 131I-metaiodobenzylguanidine: the experience of an Italian Study Group.

Eight patients affected by neuroblastoma were treated with 18 courses of 131I-meta-iodobenzylguanidine (MIBG). They all had been judged as "nonresponders" to conventional treatments. Six had stage IV disease: of these, five, with massive marrow involvement, had poor results, mainly because of marrow depression; one, whose marrow had been previously purged by chemotherapy, showed a decrease in blood cell counts but not to critical levels, thus allowing repeated treatments and some improvement. Two other cases had stage III disease, without marrow involvement. Both could receive repeated treatments without adverse effects on marrow and circulating blood cells; both could have surgical procedures when a significant neoplastic mass reduction had been induced by MIBG treatments. Almost all patients experienced reduction or disappearing of pain. Treatments were well tolerated.

3-Iodobenzylguanidine↗
PubMed1987

Diagnostic accuracy of rest-exercise first pass ventriculography with a fast single crystal gamma camera in detecting coronary artery disease. Study of a group of male subjects without previous myocardial infarction.

Rest and exercise radionuclide ventriculograms were performed in 61 non infarcted, male, patients who underwent cardiac catheterization for chest pain and in 16 normal control subjects. Studies were performed using the first pass method with a fast single crystal gamma camera, which allowed a count rate of 140 +/- 19 Kcounts/sec to be reached during left ventricular filling; the count integral on left ventricular area was 10.8 +/- 1.6 Kcounts and the maximum count/pixel 155 +/- 16. We analyzed sensitivity, specificity, positive and negative predictive value of global ejection fraction (EF) and of the regional wall motion in identifying ventricular function abnormalities due to obstructive coronary artery disease. The regional wall motion was evaluated with four functional images: regional ejection fraction (REF), amplitude (A) and phase (PH) from Fourier analysis and systolic transit times (TT). Sensitivity was near 90% for EF, REF, A and TT, while PH was less sensitive (80%); all functional images were more specific (nearly 90%) than EF (80%). Both sensitivity and specificity were lower for the exercise EKG (59% and 63%, respectively) in this patient group. Significant differences between single vessel and multiple vessel disease were also observed either for the EF increase/decrease (-1.34 +/- 7.4 and -7.82 +/- 9.96; P less than 0.05) or for the number of segments which developed wall motion abnormalities during exercise (1.22 +/- 0.73 and 2.15 +/- 1.04; P less than 0.02). In conclusion, with our method, a fast single crystal gamma camera is suitable for obtaining optimal first pass radionuclide ventriculograms with a count density sufficient either for global or regional left ventricular function evaluation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Self-inflicted tongue ulcer: an unusual form of factitious disorder.

Factitious disorders in the buccal cavity are infrequent. A 9-year-old boy with a 5-year history of an artefact ulcer of the tongue is described. Psychiatric evaluation revealed an altered personality structure with a background of psychotic traits. Complete remission was observed with psychiatric management.

Anti-Anxiety Agents↗