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Biomedical subjects

L Guerra

Publications and source records attributed to L Guerra.

At least 91 records · Page 5Linked to original sources
PubMed1995

[Multiple sclerosis. A report of a case treated with thymopentin].

The authors analyse the case of a 58-year-old male suffering from substantially "atypical" multiple sclerosis (MS), both in terms of the late onset and because of some characteristics of the course of disease. The patient was treated with a subcutaneous immunomodulator (thymopentin) at a dose of 50 mg/day in 3-monthly cycles with intervals of 2 months between cycles, for a total of 3 cycles. Instrumental (CAT-NMR) and laboratory (immunological) tests were not significant, whereas others provided complex responses that allowed the presence of a demyelinating syndrome to be ascertained, above all due to the positivity of isoelectrofocusing. Treatment with thymopentin, commenced 12 years after the clinical onset of disease and after numerous cycles of cortisone and ACTH therapy, led to a major improvement in clinical conditions, especially of "sthenia" and movement, with consequent recovery of personal autonomy and working capacity which had previously been totally lost. Immunological tests performed at the end of each treatment cycle showed some slight but interesting modifications in parameters relating to DNA and the percentage of HLA antigens bound to lymphocytes. These findings suggest that the patient's immune system was sensitive to treatment with the thymic hormone responsible for the objective clinical improvement. These results appear to open the way to the possible treatment with immunomodulators.

Adjuvants, Immunologic↗
PubMed1995

24-hour blood pressure profile early after renal transplantation.

Renal transplant patients are often found to have high blood pressure. We studied 12 cyclosporine-treated patients 8-10 days after kidney transplantation by 24-hour ambulatory blood pressure monitoring, and once again at 35-40 days after kidney transplantation. The patients were found to have high mean blood pressure values at 8-10 days after transplantation, with a significant (p < 0.05) decrease at 35-40 days after transplantation (154.2 +/- 4.9/94.4 +/- 2.8 and 142.2 +/- 4.0/88.6 +/- 2.7 mmHg, respectively). A significant (p < 0.05) decrease in blood pressure values was also noted in the second series of measurements, when compared to the first series, in the day-time systolic and in the night-time systolic and diastolic blood pressure values, but not in the day-time diastolic blood pressure values. An abnormal day/night pattern of blood pressure ("non-dipper") was found in these patients in both occasions, with a difference between average blood pressure values during day- and night-time of 1.3/3.0 (systolic/diastolic) and 5.7/7.6 mm Hg at 8-10 and 35-40 days after transplantation, respectively. This tendency towards attenuation of the "non-dipper" pattern occurred in association with the decrease in body weight and of the dose of immunosuppressive drugs. As hemodynamic factors may play a role in both the short and the long-term function and viability of kidney transplant grafts, the high blood pressure and the "non-dipper" pattern of blood pressure found early after kidney transplantation may require a special therapeutic approach.

Adult↗
PubMed1995

[Splenic lymphoma with circulating hairy lymphocytes lymphoma. Clinical cytological study of 4 patients].

PURPOSE: The splenic lymphoma with circulating villous lymphocytes (SLCVL) is an infrequent disease included within the low grade non Hodgkin's lymphoma, B-cell type. The results of the study of four patients are reported. PATIENTS AND METHODS: Clinical, cytological, immunophenotypic, ultrastructural, evolutive and therapeutic data have been revised in all the cases. RESULTS: Two males and 2 females of 76, 66, 68 and 62 years, respectively were diagnosed as having SLCVL. The initial symptoms were scarce, basically asthenia, and a big spleen without significant lymphadenopaty was the most relevant physical finding in each of them. In peripheral blood leukocyte count was normal with a slight lymphocytosis and a variable percentage of villous circulating lymphocytes. The immunophenotype of peripheral blood obtained by flow cytometry was according with a mature B-cell lymphocyte population, CD 5 and CD 25 negative. The cells were positive to acid phosphatase with a diffuse pattern of variable intensity; the reaction was inhibited by tartaric acid. All the patients had BM infiltration, studied with aspiration and biopsy. One case (M,66) had an IgM monoclonal gammopathy. The ultrastructural study, performed in 3 cases, showed thin and short villous prolongations. After splenectomy, a low degree lymphoma therapy has been employed in all the cases. The follow-up ranges between, 4 years and 4 months, all the patients being alive. CONCLUSIONS: The SLCVL is a definitive entity regarding the clinical, morphologic and immunophenotype features. A long clinical evolution and a good prognosis after splenectomy are common.

Aged↗
PubMed1994

Binding characteristics of the adenosine A2 receptor ligand [3H]CGS 21680 to human platelet membranes.

The binding characteristics of the selective adenosine A2 agonist [3H]CGS 21680 ([3H]2-[p-(2-carboxyethyl)-phenethyl-amino]-5'-N- ethylcarboxamidoadenosine) were determined in human platelet membranes. Specific binding was saturable, reversible and dependent upon protein concentration. Saturation experiments revealed a single class of binding sites with Kd and Bmax values of 1.4 microM and 5.9 pmol/mg of protein, respectively. Adenosine receptor agonists and antagonists competed for the binding of [3H]CGS 21680 (50 or 200 nM) to human platelet membranes showing a rank order of potency consistent with that typically found for interactions at the adenosine A2 receptor. Adenylate cyclase stimulation and platelet aggregation inhibition induced by adenosine agonists exhibited a rank order of potency close to that observed in binding experiments. However, the adenosine A1 receptor agonists, R- and S-N6-(2-phenylisopropyl)adenosine, (R-PIA) and (S-PIA), N6-cyclohexyladenosine (CHA) and 2-chloro-N6-cyclopentyladenosine (CCPA), which stimulate adenylate cyclase and inhibit platelet aggregation in the low microM range, displaced [3H]CGS 21680 only in the high microM range. In conclusion, we have found that [3H]CGS 21680, which is widely used as a specific A2 agonist in binding studies on brain tissues, is not appropriate for the characterization of the human platelet adenosine A2 receptor.

Adenosine↗
PubMed1994

Electrophysiological basis for the enhanced cardiac arrhythmogenic effect of isoprenaline in aged spontaneously hypertensive rats.

We used normotensive (WKY) and spontaneously hypertensive rats (SHR) of 2, 6 and 18 months of age to get insight into the mechanisms responsible for the increased incidence of ventricular arrhythmias in hypertensive heart disease. We studied: (1) isoprenaline-induced spontaneous activity in isolated papillary muscle; (2) action potential characteristics; (3) beta-adrenoceptor and A1-adenosine receptor number and affinity; and (4) intracellular cyclic AMP (cAMP) levels. The saturation binding assay was performed in enzymatically isolated ventricular myocytes using the hydrophilic antagonist 3H-CGP 12177 for beta-adrenoceptors and 3H-DPCPX for A1-adenosine receptors. cAMP was measured by a competitive binding assay in myocytes before and after exposure to isoprenaline. Intracellular action potential was recorded from papillary muscles by means of 3 M KCl-filled glass microelectrodes. The presence of isoprenaline-induced automaticity was assessed by interrupting the electrical stimulation periodically. In isolated papillary muscles, isoprenaline (10 nM) induced spontaneous activity more frequently in 18-month-old SHR (90.0%) than in 6-(25.0%, P < 0.05) and 2-month-old SHR (0%, P < 0.001). No age-related statistically significant differences in isoprenaline-induced automaticity were observed in WKY. The incidence of isoprenaline-induced automaticity was higher in 18-month-old SHR than in age-matched WKY (22.2%, P < 0.05). KD and Bmax for beta-adrenoceptors and A1-receptors were not significantly modified in different groups. cAMP levels before and after isoprenaline stimulation were significantly lower in 18-month-old SHR than in age-matched WKY. Action potential duration (APD) was markedly prolonged in both normotensive and hypertensive rats during aging. APD was significantly prolonged in 18-month-old SHR compared to the WKY. A "diastolic depolarization", caused by the presence of delayed after-depolarizations, became apparent in the oldest animals. The slope of the delayed after-depolarization was increased by isoprenaline (1-10 nM) in 18-month-old SHR and this effect was significantly greater than that observed in 18-month-old WKY (P < 0.05). In conclusion, beta-adrenergic responsiveness is enhanced in hypertensive rats during aging, resulting in a greater incidence of abnormal automaticity. This effect does not appear to be related to changes in beta-adrenoceptor or A1-receptor density or affinity; it is likely that the electrophysiological alterations may play a role in this phenomenon.

Action Potentials↗
PubMed1994

Phentolamine and hypoxia: modulation of contractility and alpha 1-adrenoceptors in isolated rat atria.

The hypoxia-induced effects on the binding sites and affinity constant of adrenoceptors, in the presence and absence of phentolamine, were determined for atrial membranes of hearts from normal and genetically hyperlipidaemic Yoshida (YOS) rats. Atrial function was also measured during normoxia and hypoxia, in the presence and absence of phentolamine. Hypoxia increased alpha 1-adrenoceptor density in atrial membranes of normal rats (Bmax 10.6 to 26.7 fmoles/mg protein). Phentolamine prevented the increase in the Bmax of alpha 1-adrenoceptors and increased the equilibrium dissociation constant of these receptors (KD 0.17 to 0.53 nmol/l). Beta-adrenoceptors did not change during hypoxia, but the Bmax was slightly increased (26%) in the presence of phentolamine. Thus, the alpha 1/beta ratio increased from 0.40 in normoxia to 1.06 in hypoxia. In normoxic atria from YOS rats, the alpha 1/beta ratio was already elevated (0.86) in comparison to control rats (mainly due to a higher density of alpha 1-adrenoceptors in atrial membranes from YOS rats). This ratio was not modified by hypoxia (0.84), but decreased when phentolamine was present (0.30). Hypoxia reduced the force of contraction and increased diastolic tension of atria of normal rats, while the sinus rate was not significantly modified. Phentolamine abolished the increase in diastolic tension and reduced the negative effect of hypoxia on contractile force. In YOS rat atria, functional parameters were modified by hypoxia in a qualitatively similar way to that of normal rat atria.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Multicenter study of childhood headache.

This multicenter study reports the results obtained between 1990 and 1991 by the Study Group for Childhood Headache of the Italian Neuropediatric Society. Standardized computerized case sheets were used in order to increase the number of young patients studied and obtain more homogeneous results. A clinical diagnosis of headache was made in 600 patients (314 female and 286 male) between 4 and 12 years of age, in accordance with the classification set down by the International Headache Society. Clinical symptoms and follow-up were more severe in children with migraine as opposed to headache. No sequence of associated neurological and neurovegetative symptoms was observed at onset of headache, and some (phono-photophobia, pallor, drowsiness, abdominal pains) were much more prevalent than others. Because of the patient's age we studied only the treatment of acute attack and did not take account of chronic treatment. In childhood the clinical course of primary headache tends to improve spontaneously, and we believe that prevention of headache attacks should be carried out only in very rare individual cases.

Acute Disease↗
PubMed1994

Sunscreen sensitization: a three-year study.

BACKGROUND: In the last decade UV filters have been incorporated in a large number of cosmetic products. OBJECTIVE: The purpose of our study was to evaluate the prevalence of sunscreen allergy in patients with a suspected photodermatitis. METHODS: 108 patients were patch-tested with the Gruppo Italiano Ricerca Dermatiti da Contatto e Ambientali (GIRDCA) standard series and photopatch-tested with the photopatch series. RESULTS: Allergy and/or photoallergy to sunscreening agents was diagnosed in 8 subjects (7.4%). Oxybenzone was positive in 4 patients, isoproyl dibenzoylmethane in 3 patients, p-aminobenzoic acid and 2-ethylhexyl-p-methoxycinnamate in 1 patient, respectively. CONCLUSION: Our results obtained during a 3-year period (January 1990 to June 1993) confirm that sunscreens are presently the commonest photoallergens.

Adolescent↗
PubMed1994

Alopecia areata. A pathological study of nonresponder patients.

Fourteen patients, four male and 10 female and ranging in age from 11 to 57 years, affected by longstanding alopecia areata that had not responded to sensitizing treatments, were submitted to scalp biopsy. Five patients had alopecia totalis and nine had alopecia universalis. The biopsy was performed on a scalp area that had been bald for > or = 1 year. We distinguished four distinct pathological patterns, which we termed "established bald patch," "early regrowth," "telogen," and "scarring," in four, seven, one, and two patients, respectively. Our study shows that, from a pathological point of view, nonresponder patients constitute a heterogeneous population. The pathological study of the scalp helps predict therapeutic failure only in the small proportion of nonresponder patients that shows a scarring pathological pattern.

Adolescent↗
PubMed1993

Molecular cloning of trkE, a novel trk-related putative tyrosine kinase receptor isolated from normal human keratinocytes and widely expressed by normal human tissues.

We have identified and cloned a new member of the trk gene family, termed trkE, which generates a 3.9-kilobase (kb) transcript in normal human keratinocytes and in a variety of normal human tissues, but not in liver. Albeit at low level, trkE transcript is expressed also by PC12 cells. The open reading frame codes for a polypeptide of 876 amino acids exhibiting the classic features of cell surface tyrosine protein kinases. trkE catalytic domain is 41% identical to trkA and shows several features unique to the trk gene family. Its extracellular domain does not show significant homology to any known proteins. trkE is the first member of this gene family found abundantly and widely expressed in normal human tissues. Several lines of evidence suggest that NGF is also the ligand for trkE; (i) normal human keratinocytes bind NGF with high affinity, (ii) NGF stimulates keratinocyte growth in an autocrine fashion, (iii) NGF exerts its biological effect on keratinocytes through the stimulation of a trk-specific tyrosine kinase, and (iv) keratinocytes lack trkA but do express large amount of trkE. trkE might also be the NGF receptor by other human peripheral tissues, such as pancreatic islets, and might represent a non-neuronal receptor for this ligand.

Amino Acid Sequence↗
PubMed1993

Taxol sensitizes human ovarian cancer cells to radiation.

Taxol is an exciting antineoplastic agent with a novel mechanism of action. This study was designed to explore the potential use of taxol as a radiation sensitizer. Three human ovarian cancer cell lines were used: BG-1, SKOV-3, and OVCAR-3. These cell lines were treated in the proliferative and confluent state with taxol doses of 0.0001X, 0.0005X, 0.001X, 0.005X, and 0.01X peak plasma concentration of taxol for 90 min and then irradiated either 24 or 48 hr later. Doses of cobalt60 were 0, 2, 5, 8, and 10 Gy. ATP bioluminescence assays were performed on Day 7 after irradiation. Survival data was fit to the linear-quadratic model and mean inactivation dose D was calculated. Data analysis with t test and analysis of variance was performed. Taxol was found to have a significant radiosensitizing effect on all cell lines. Proliferating cells were more sensitive to taxol, radiation, and the combination than confluent cells. Treatment of proliferating cells with taxol 48 hr prior to irradiation had a greater radiosensitizing effect than treatment 24 hr prior to irradiation. In summary, taxol is a potent radiosensitizer in ovarian cancer cell lines and should be considered for further study.

Adenosine Triphosphate↗
PubMed1993

Vasopressin-dependent control of basolateral Na/H-exchange in highly differentiated A6-cell monolayers.

We have used a well-differentiated A6-cell preparation (A6-C1) to study cellular location and vasopressin control of Na/H-exchange activity. After cell acidification, cell pHi (measured by BCECF-fluorescence) only recovered by the addition of Na medium to the basolateral cell surface; this pHi recovery was inhibited by dimethylamiloride (2 microM) consistent with basolateral location of Na/H-exchange activity. Addition of vasopressin produced stimulation of Na/H-exchange activity and increased the affinity of the exchanger for Na+. Stimulation of Na/H exchange was mimicked by pharmacological activation of protein kinase A (forskolin, 8-Br-cAMP) and not by pharmacological activation of protein kinase C (TPA). It is concluded that basolaterally located Na/H-exchange in A6-C1 cells is activated by vasopressin.

Animals↗
PubMed1993

Recurrent basal cell carcinoma of the back infiltrating the spine. Recurrent basal cell carcinoma.

BACKGROUND: Risk of basal cell carcinoma (BCC) recurrence appears to be related to tumor location, tumor size, treatment modality, radicalness of excision, and histologic type. Recurrences of BCC on the trunk and extremities are rare, with 97% of all recurrent lesions being located in the head and neck region. OBJECTIVE: This report concerns a man who had a BCC of the back removed with electrodesiccation and curettage in 1980 at the age of 36. In the following 10 years the patient experienced five recurrences and finally developed infiltration of the thoracic spine that precluded further attempts at radical excision of the neoplasm. METHODS AND RESULTS: The pathology of the BCC in our patient revealed a number of histologic features that have been associated with aggressive behaviour. These include an infiltrative growth pattern characterized by an irregular and acute tapered profile of the tumor cell groups and fibroblast-rich stroma, infiltrating invading tumour edges, poorly peripheral palisading, nuclear pleomorphism, and perineural invasion. CONCLUSION: Basal cell carcinomas that occur in sunlight-protected areas of the trunk of middle-aged individuals can occasionally exhibit aggressive and highly invasive features as well as a marked tendency for local uncontrollable recurrences. The prognosis for patients with this variety of BCC is poor, especially when progressive infiltration of deep tissues does not permit, as in our case, any possible further radical surgical procedure.

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