Isoelectric focusing in immobilized pH gradients: generation and optimization of wide pH intervals with two-chamber mixers.

A new technique for generating extended pH gradients (5 pH units) in Immobiline gels is reported. The previously described (J. Biochem. Biophys. Methods 7, 1983, 123-142) five-chamber gradient mixer has been replaced by a two-vessel device. A single mixture of the available Immobilines (pK 3.6, 4.6, 6.2, 7.0, 8.5 and 9.3) is made, with relative concentrations adjusted so as to produce the most uniform buffering power throughout the desired pH interval. This mixture is then divided into two portions, which are titrated to the extremes of the required pH span with an acidic titrant (Immobiline pK approximately 1) and a basic species (Immobiline pK 9.95). Highly reproducible pH gradients (pH 4-9) are thus generated, which appear extremely useful for the first dimensioned of 2-dimensional techniques. Our previously reported computer program has been implemented with an optimization algorithm which, given any cocktail of Immobilines, automatically adjusts the relative initial concentrations until the smoothest possible beta power is found. For the first time it is possible to perform IEF under controlled physico-chemical parameters: pH span and linearity, beta power, ionic strength and molarity of the buffering species.

An integrated system for the automation of the clinical chemistry laboratory.

A user programmable microcomputer-based integrated system for automatic analysis in the clinical chemistry laboratory is presented. Friendly user-instrument interaction helps the operator when defining tests and analytical conditions or entering sample data and test requests. Quality control data are retained for the automatic production of various statistical lists and graphs. Routine operator intervention is limited to reagent preparation, sample loading onto the autosampler plate, definition of the tests to be performed on each of the samples and data validation before the generation of reports. Finally, connection with an existing laboratory management system is provided by means of a standard serial interface.

Isoelectric focusing in immobilized pH gradients: generation of extended pH intervals.

A new technique for generating extended pH gradients (3-4 pH units) in Immobiline gels for isoelectric separations is described. A five-chamber gradient mixer has been built, based on the 'Varigrad'-type mixers of Peterson and Sober (Anal. Chem. 31, 1959, 857-862). Each chamber contains one of the following Immobilines, in this order: pK values 4.4, 4.6, 6.2, 7.0 and 8.5, titrated in the pH 4-8 interval with non-buffering Immobilines pK 9.3 (in the case of the two acidic Immobilines) and pK 3.6 (in the case of the three basic Immobilines). In this way it is possible to cast, in a highly reproducible way, an immobilized pH gradient in the pH range 4.0 to 7.5, which should be ideal for isoelectric separations in the first dimension of two-dimensional techniques. A computer program is also described which, given the molarities and pK values of the different Immobilines in the chambers of the Varigrad mixer, can generate the theoretical pH profile, together with the buffering capacity (beta) and ionic strength (I) courses.

Measurement of glucose in plasma by a differential pH technique.

A new automatic apparatus based on the differential measurement of pH between two solutions has been developed. Two 25-microL (internal volume) glass capillary electrodes are used to measure the results of automated (under microcomputer control) chemical reactions that lead to the liberation or the uptake of hydrogen ions. The sensitivity of the differential pH measurements is better than +/- 0.0001 pH unit, and the change in H+ concentration that can be detected by such an apparatus is 1 mumol/L for plasma and 3 mumol/L for whole blood. The technique has been applied to the measurement of glucose in plasma, giving results in agreement with the specifications of the Food and Drug Administration reference method for quantitative determination of glucose (hexokinase/glucose-6-phosphate dehydrogenase method).

[Organization of a patient's file of a radio-chemo-therapy department by means of a mini-computer (author's transl)]. / Organizzazione di un archivio pazienti di un reparto di radio-chemio-terapia mediante minicomputer.

The clinical research in the oncological field makes it necessary to have in the shortest possible time information as to the statistical elements of the various neoplasias according to the adopted treatment schemes. In this report we are going to describe the realization of a computerized file with the patient's data of our radio-chemo-therapy department. From the clinical report of each patient, according to the physician's judgement, the more important medical and anagraphical data have been taken out to be then memorized in the computer. The analysis of the data introduced allows to obtain an inventory of patients in alphabetical order, according to the type of neoplasia and to the type of the treatment. The system is quite easy to be used and the interaction with the user is dialogue oriented. In this way both the inserting and the research stage of the filing data as well as the printing of the lists can be effected even by people not particularly trained in the computer use.

Simplified computerization of data-base for diabetic patients.

A computerized data-base for the management of the out-patient clinic for diabetes and of the hospital diabetic patients has been developed by means of low cost commercial microcomputer. The program is able to supply lists of sets of patients chosen from user-defined characteristics. The system also allows the selected listin of recall letters for periodic examinations, the printing of registers for medical and administrative use and for statistical analysis. The system is easy to learn and easy to use. The operator-computer interaction is colloquial through the use of a video-terminal, permitting the use by nominally-trained staff.

Insulin given intranasally induces hypoglycaemia in normal and diabetic subjects.

Regular or crystalline insulin with sodium glycocholate as surfactant administered intranasally to normal volunteers induced hypoglycaemia and an increase in serum immunoreactive insulin concentrations. Serum C-peptide concentrations decreased or remained unchanged. Insulin administered intravenously to three of these subjects yielded a potency ratio of 1:8 for intranasal and intravenous insulin. In four insulin-dependent diabetics a cross-over study was performed on different days, insulin being administered once intranasally and once subcutaneously in a ratio of 1:9. In these patients the intranasal insulin was more effective than the subcutaneous insulin in preventing hyperglycaemia after breakfast. In four other insulin-dependent diabetics 11-hours monitoring was performed twice on two different days, insulin being administered in divided dosage sufficient to achieve a reasonable glycaemic profile. The administration during the morning, whereas subcutaneous insulin was more effective than intranasal during the afternoon.

Glucose-clamp by artificial pancreas in the study and management of a patient with insulinoma.

Four euglycemic glucose-clamp studies by artificial pancreas (Biostator, Miles) have been performed during prolonged fast before and after pharmacological treatment in a patient with insulinoma. In the basal state a high glucose infusion rate (8.9 g/h) was unable to achieve the preselected blood glucose plateau of 80 mg/100 ml. The plasma insulin levels during this first glucose-clamp were comprised between 18 and 50 microunits/ml. On the first day of diazoxide treatment (300 mg/die),. the glucose infusion rate decreased to 6.4 g/h, without variation in plasma insulin level, thus suggesting a diazoxide effect independent of the inhibition of insulin secretion. After 7 days of diazoxide treatment, a further reduction of glucose infusion (5.8 g/h), together with a lowering of plasma insulin levels (7-18 microunits/ml) was observed. Both in the basal state and during diazoxide treatment a circadian pattern of glucose requirement was noted, with lower glucose need and plasma insulin levels during the night. Surgery was undertaken with glucose-clamp by artificial pancreas; blood glucose level being higher than the preselected value of 80 mg/100 ml, simple monitoring of glycemia was performed. The excision of a single adenoma was followed by a substantial rise in blood glucose 20 min later. An additional glucose-clamp, performed 3 months after surgery showed a dramatic fall of the glucose infusion rate (2.9 g/h) needed to achieve the preselected blood glucose plateau, confirming the completeness of the intervention. This experience shows that glucose-clamp by artificial pancreas may be of great value in the study as well as in the pharmacological and surgical treatment of patients with insulinoma.