Transplantation of islets of Langerhans in diabetic rats.

In the present work, homogeneous isolated pancreatic islet-cells were transplanted to diabetic rats with the aim of verifying if the transplanted tissue could survive and reduce the plasma glucose concentration on the alloxan-induced diabetic receptors. For the isolation of the pancreatic islets, pancreas was incubated in collagenase solution for about 13 +/- 3 minutes, followed by centrifugation in Ficoll gradients. The islets, 3 000 to 5 000, were transplanted to alloxan diabetic recipients, in a territory, preferentially with portal-hepatic drainage (mesentery and spleen). Sixty per cent of the recipients exhibited a fall of the plasma glucose concentration, up to 70%, while in the control animals, the diabetes persisted. The islets were found in the recipients mesentery up to 10 days after transplantation, and all of them showed heavily granulated (aldehyde fuchsin positive) beta cells. After this time, islets were not found. These results indicate that islets can survive and attenuate diabetes in alloxan-treated rats, and that, probably, the number of islets transplanted as well as the receiving areas play an important role.

Transplantation of islets of Langerhans in diabetic rats.

In the present work, homogeneous isolated pancreatic islet-cells were transplanted to diabetic rats with the aim of verifying if the transplanted tissue could survive and reduce the plasma glucose concentration on the alloxan-induced diabetic receptors. For the isolation of the pancreatic islets, pancreas was incubated in collagenase solution for about 13 +/- 3 minutes, followed by centrifugation in Ficoll gradients. The islets, 3 000 to 5 000, were transplanted to alloxan diabetic recipients, in a territory, preferentially with portal-hepatic drainage (mesentery and spleen). Sixty per cent of the recipients exhibited a fall of the plasma glucose concentration, up to 70

, while in the control animals, the diabetes persisted. The islets were found in the recipients mesentery up to 10 days after transplantation, and all of them showed heavily granulated (aldehyde fuchsin positive) beta cells. After this time, islets were not found. These results indicate that islets can survive and attenuate diabetes in alloxan-treated rats, and that, probably, the number of islets transplanted as well as the receiving areas play an important role.

Transplantation of islets of Langerhans in diabetic rats

In the present work, homogeneous isolated pancreatic islet-cells were transplanted to diabetic rats with the aim of verifying if the transplanted tissue could survive and reduce the plasma glucose concentration on the alloxan-induced diabetic receptors. For the isolation of the pancreatic islets, pancreas was incubated in collagenase solution for about 13 +/- 3 minutes, followed by centrifugation in Ficoll gradients. The islets, 3 000 to 5 000, were transplanted to alloxan diabetic recipients, in a territory, preferentially with portal-hepatic drainage (mesentery and spleen). Sixty per cent of the recipients exhibited a fall of the plasma glucose concentration, up to 70

, while in the control animals, the diabetes persisted. The islets were found in the recipients mesentery up to 10 days after transplantation, and all of them showed heavily granulated (aldehyde fuchsin positive) beta cells. After this time, islets were not found. These results indicate that islets can survive and attenuate diabetes in alloxan-treated rats, and that, probably, the number of islets transplanted as well as the receiving areas play an important role.

[Right ventricle--pulmonary artery diastolic blood flow (author's transl)]. / Fluxo diastólico ventrículo direito--artéria pulmonar

The authors show the possibility of the establishment of blood flow from the right ventricle to the pulmonary artery during the period of ventricular diastole, through experimental models mimetizing hemodynamic patterns described in the literature for certain cardiopathies. These models consisted of experimental hypodiastoly, associated or not with right ventricle hyposystoly. The detection of the existence or not of blood flow in the several phases of the cardiac cycle, was made recording the variations of the electrical impedance of the blood.

[Pre-systolic deflexion in pressure recordings of the right ventricle and pulmonary artery (author's transl)]. / Deflexão pré-sistólica nos registros pressóricos do ventrículo direito e da artéria pulmonar

The authors demonstrated experimentally that the origin of the pre-systolic deflexion, previously observed by many investigators in pressure recordings of the right ventricle and the pulmonary artery, is due to the effective atrial contraction, which, besides the pressure change, produces a blood flow from the ventricle towards the artery. This flow must possibly exert an important role in the maintenance of the cardiac output when a failure of the right ventricle is established.

[An impedance measuring technique for blood flow qualitative recording]. / Técnica impedanciométrica de detecção de fluxo sanguíneo.

An impedance measuring technique was developed for blood flow qualitative recordings in laboratory animals. Basically, it consists in the administration of an indicator solution (0,1 ml, NaCl 20%) which, mixing with the blood, provokes a decrease in its electrical resistance, in such way that the passage of this mixture (concentrated saline/blood) through a bipolar receptor electrode, resistively balanced by the electrical impedance of blood alone, will be detected as a sudden resistance fall. The results so far show that it is an adequate technique for blood flow qualitative studies, since, despite its simplicity, provides consistent and unequivocal recordings which, performed simultaneously with those of other circulatory events, may become a helpful tool for their understanding.