Intracellular calcium in the isolated rat liver: correlation to glucose release, K(+) balance and bile flow.

This study correlates whole organ measurements of intracellular calcium concentration ([Ca(2+)](i)) with hormone-induced (epinephrine, vasopressin) changes of liver functions (glucose release, K(+) balance and bile flow). [Ca(2+)](i) was measured in the isolated perfused rat liver using the sensor Fura-2 and applying liver surface fluorescence spectroscopy. The technique was improved by (i) minimizing biliary elimination of the sensor by employing a rat strain deficient in canalicular organic anion transport (TR(-) mutation) and (ii) by correcting for changes of interfering intrinsic organ fluorescence that was shown to depend on the oxidation-reduction state (NAD(P)H content) of the organ. Epinephrine (50 nM) elicits an instantaneous peak rise of [Ca(2+)](i) to approx. 400 nM, followed by a sustained elevation that depends on the presence of extracellular Ca(2+). The rise of [Ca(2+)](i) coincides with initiation of glucose release, transient K(+) uptake, and transient stimulation of bile flow. Vasopressin (2 nM) exerts qualitatively similar effects. The transient rise of bile flow is attributed to Ca(2+)-mediated contraction of the pericanalicular actin-myosin web of hepatocytes.

Effects of insulin-like growth factor I on basal and stimulated glucose fluxes in rat liver.

Effects of insulin-like growth factor I (IGF-I) and insulin on glucose and potassium fluxes were examined by measuring transhepatic glucose and potassium balance in isolated perfused rat livers. At 1 nM, both IGF-I and insulin decreased basal glucose release by approximately 64% (P < 0.05). Adrenaline (epinephrine)-stimulated glucose release (42.6 +/- 4.5 micromol/g of liver within 30 min) was inhibited (P < 0.05) by approximately 32 and approximately 52% during IGF-I and insulin exposure, which was accompanied by reduced cAMP release (-71 and -80%, P < 0.05). IGF-I- and insulin-induced reduction of glucose release only decreased during calcium-free perfusion, but not during inhibition of phosphoinositide 3-kinase by wortmannin. Both IGF-I and insulin induced net potassium uptake, while insulin also attenuated the response to adrenaline. In conclusion, IGF-I causes (i) insulin-like inhibition of hepatic glycogenolysis, even at low, nanomolar concentrations, which is associated with decreased cAMP release, reduced in the absence of Ca(2+), but not mediated by phosphoinositide 3-kinase, (ii) reduction of adrenaline-induced glycogenolysis and (iii) net potassium uptake under basal conditions.

[Trace elements in samples of brittle and nonbrittle finger nails]. / Spurenelemente in Proben brüchiger und nicht-brüchiger Fingernägel.

We examined nail samples of 27 adult patients suffering from brittle nails and 15 persons without nail disorders with respect to the content of trace elements. The analysis by atomic absorption spectroscopy disclosed the following values. In parentheses values of healthy nails. Ca 44.9 ppm +/- 25.0 (53.6 ppm +/- 22.5), Mg 182.4 ppm +/- 128.0 (183.1 ppm +/- 83.2), Al 25.6 ppm +/- 10.3 (33.0 ppm +/- 20.5), Cu 7.9 ppm +/- 3.0 (7.9 ppm +/- 2.7), Zn 80.9 ppm +/- 34.5 (85.0 ppm +/- 34.9), Fe 53.9 ppm +/- 24.5 (45.7 ppm +/- 24.4). Comparing the two groups no significant differences could be found.

Incidence of brittle nails.

Only few reports exist about the occurrence of brittle nails. We examined 1,584 persons with respect to the incidence of this anomaly. The patients were from five different groups: outpatients of a dental clinic, blood donors, residents of an old people's home, patients of a clinic for internal diseases and patients of a general practice. Approximately 20% of the subjects examined had brittle nails. Women suffered from brittleness of nails much more frequently than men (27 vs. 13%) with a ratio of men to women from 1:1.6 to 1:7 depending on age. 44% of the subjects affected (75% of the females, 25% of the males) had tried one or several treatments but only 26% believed in their curative effect. The market for the therapy of brittle nails in the FRG is estimated to be between 2 and 4 million people.