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S Sala

Publications and source records attributed to S Sala.

50 records · Page 3Linked to original sources
PubMed1991

Analysis and use of the perforated patch technique for recording ionic currents in pancreatic beta-cells.

We have used the nystatin perforated patch technique to study ionic currents in rat pancreatic beta-cells. The access resistance (Ra) between the pipette and the cell cytoplasm, measured by analyzing capacitive currents, decreased with a slow exponential time course (tau = 5.4 +/- 2.7 min) after seal formation. As Ra decreased, the magnitude of voltage-dependent K and Ca currents increased with a similar time course, and their activation kinetics became faster. After Ra stabilized, the macroscopic currents remained stable for up to an hour or more. When the final Ra was sufficiently low, Ca tail currents could be resolved which had properties similar to those recorded with the classical whole-cell technique. Two types of K channels could be characterized with perforated patch recordings of macroscopic K currents: (i) ATP-blockable K (KATP) channels which generate a time and voltage independent current that is blocked by glyburide and enhanced by pinacidil and (ii) voltage-dependent K (Kv) channels. Whole-cell recordings of KATP currents in the absence of ATP in the pipette showed that the maximum KATP conductance of the beta-cell was 83.8 +/- 40 nS. Perforated patch recordings show that the resting KATP conductance is 3.57 +/- 2.09 nS, which corresponds to about 4% of the channels being open in the intact beta-cell. In classical whole-cell recordings. Kv activation kinetics become faster during the first 10-15 min of recording, probably due to a dissipating Donnan potential. In perforated patch recordings where the Donnan potential is very small, Kv activation kinetics were nearly identical to the steady-state whole cell measurements.

Adenosine Triphosphate↗
PubMed1991

Voltage-dependent slowing of K channel closing kinetics by Rb+.

We have studied the effect of Rb+ on K channel closing kinetics in toadfish pancreatic islet cells. These channels are voltage dependent, activating at voltages positive to -10 mV. The channels also inactivate upon prolonged depolarizations, and the inactivation time course is best fit by the sum of two exponentials. Instantaneous current-voltage relationships show that external Rb+ enters the channel as easily as K+, but carries less current. In the voltage range from -140 to -50 mV, the closing time course of the channels can be fit with a single exponential. When Rb+ is present in the external solution the channels close more slowly. The magnitude of this Rb+ effect is voltage dependent, decreasing at more negative voltages. Similarly, when the internal solution contains Rb+ instead of K+ the closing time constants are increased. The effect of internal Rb+ is also voltage dependent; at voltages positive to -80 mV the closing time constant in internal Rb+ is slower than in K+, whereas at more negative voltages the difference is negligible. With internal Rb+, the relationship between the closing time constant and voltage is best fit with two exponential components, suggesting the presence of two distinct voltage-dependent processes. The results are discussed in terms of a model of the K channel with two internal binding sites, and we conclude that Rb+ produces its effects on channel gating by binding to a site in the pore.

Animals↗
PubMed1991

[Prognostic factors in adenocarcinoma of the endometrium].

We report the results of the combined use of surgery and radiation therapy in the treatment of endometrial carcinoma. From January 1974 to December 1989, 89 cases were treated by means of abdominal hysterectomy followed by external radiation therapy. Actuarial survival at 5 years is 100% for stage I, 75% for stage II, and 42.86% for stage III; stage IV patients could not be evaluated. Prognostic factors were statistically significant. In stages II and III survival rates were directly related to histological grading (G1: 90.91%; G2: 81.82%; G3: 25%) and to myometrial infiltration (M1: 85.71%; M2: 81.82%; M3: 70%). Generally, survival was related to age, and prognosis was better in younger patients (under 55) and depended on lymph nodal involvement (N-: 88.24%, versus N+: 25%). Vaginal and pelvic recurrences were 8 (10.1%), and deaths were 13. The identification of high-risk patients will make it possible to select an even more adequate treatment.

Adenocarcinoma↗
PubMed1990

Single-channel recordings of two types of calcium channels in rat pancreatic beta-cells.

Using the cell-attached configuration of the patch clamp technique, we have identified two different types of Ca channels in rat pancreatic beta-cell membranes. The two channels differ in single channel conductance, voltage dependence, and inactivation properties. The single-channel conductance, measured with 100 mM Ba2+ in the pipette, was 21.8 pS for the large channel and 6.4 pS for the small channel. The large-conductance channel is similar to the fast deactivating or L-type Ca channel described in other preparations. It is voltage dependent, has a threshold for activation around -30 mV, and can be activated from a holding potential of -40 mV. On the other hand, the small-conductance Ca channel is similar to the SD or T type Ca channel; it has a lower activation threshold, around -50 mV, and it can be inactivated by holding the membrane potential at -40 mV.

Animals↗
PubMed1988

[Optimization of the radiotherapy dosage in vertebral metastases].

The authors describe the radiation therapy treatment planning used in the Department of Radiotherapy of Mauriziano Hospital, Turin, to treat bone metastases from various tumors. The study population consisted of 33 patients with vertebral metastases. Treatment with a 60Co therapy unit was performed following either a conventional or a concentrated schedule. The association of a direct posterior field and a rotational technique with the same center and swing angle varying from 120 degrees and 150 degrees is described. The dose percentage given with the two techniques, the field width and the arching angle variables related to depth and volume of the target are discussed. We present some examples elaborated with a dedicated computer by calculating the integral area dose to the whole body and to the target, towards the best treatment planning for every kind of treatment proposed in two groups of six patients with vertebral and sacral metastases. The technique allows a homogeneous dose distribution to the target, thus reducing the area dose to the whole body, which means good radiotherapeutic results.

Cobalt Radioisotopes↗
PubMed1987

[The Chernobyl accident. Evaluation of the doses absorbed by the thyroid gland in children of a mountain community from the measurement of I131 retained activity].

I131 thyroid uptake after the Chernobyl's accident was sampled in a Val Pellice school. Children were grouped according to sex, age and area of residence. The procedure used in collecting data and calculating the transformation coefficients from activity counts by computer simulation is analysed, as are the errors and sensitivity of the method. The activities were then converted into doses using an intake model. The dose levels identified are lower than the estimates based on the measurement of environmental matrices. Statistical analysis revealed certain subgroups with significantly different levels of absorption: particularly groups accustomed to a different diet or living in particular areas.

Accidents↗
PubMed1984

[Dosimetric study in vivo, using a computer, of Co-60 irradiation of patients with breast prosthesis made of silicone].

This work studies the dose distribution through the chest wall in radiation therapy after mammary reconstruction with silicone prostheses. TLD experimental dosimetry has been done on patient with silicone prostheses, on patient without prostheses and on Alderson phantom. Various conditions of treatment have been theorically simulated on a computer. At least authors show the results evaluating the dose distribution through the chest wall, the skin and the local complications.

Breast↗
PubMedDate not supplied

Gastric volvulus associated with congenital diaphragmatic hernia, wandering spleen, and intrathoracic left kidney: CT findings.

We present an unusual case of gastric volvulus associated with wandering spleen, a delayed manifestation of congenital diaphragmatic hernia and left intrathoracic kidney. Gastric volvulus should be considered in any infant with unexplained vomiting and left diaphragmatic anomaly: in these patients, developmental disorders of the peritoneal visceral attachments of the left upper abdomen may coexist. The absence of ligamentous connections between the stomach, posterior abdominal wall, and spleen result in wandering spleen. We emphasize prompt surgical therapy to avoid gastric and splenic necrosis. Radiologic findings and the appearance of this complex congenital malformation are reported.

Child↗
PubMedDate not supplied

Interventional radiology in percutaneous management of bile duct obstruction: biliary drainage through a spontaneous common hepatic duct-duodenal fistula.

Bile duct injuries are a serious complication of biliary surgery. We report a case of benign obstruction of the common hepatic duct associated with common hepatic duct-duodenal spontaneous fistula following complex surgical intervention. We managed percutaneously the fistula with balloon dilatation and long-term stenting, as the fistula allowed biliary flow in the duodenum. We avoided reintervention preserving biliary flow, with good clinical results after a follow-up of a 3 years. We emphasize the role of a clinically focused approach to percutaneous management of complications following biliary surgery.

Bile Duct Diseases↗
PubMedDate not supplied

[A method of quality control in thermoluminescent dosimetry].

This work suggests a quality control method for thermoluminescent dosimetry. For each set of dosemeters, read-out has been made at increasing values of dose, on the base of predetermined conditions in different read-out techniques and from different operators. The statistical analysis of each possible group of T.L.D. permitted us to draw the error-response curves and the relative precision profiles and to select the best evaluation techniques and the best operator on the base of precision, sensitivity and useful range.

Dose-Response Relationship, Radiation↗