J. Thode

Influence of Epidural Analgesia on the Catecholamine and Cyclic AMP Responses to Surgery

The effects of neurogenic block on plasma concentrations of adrenaline, noradrenaline and cyclic AMP were studied. Eighteen patients were subjected to surgery of moderate or minor extent under enflurane anesthesia with or without epidural analgesia. The results show that adrenaline secretion during surgical stress is a response to neurogenic stimuli, since the increase found in patients subjected to hysterectomy under general anesthesia is blocked by the addition of epidural analgesia. Furthermore, plasma adrenaline after neurogenic block is comparable with adrenaline levels during minor surgical stress.

Direct reading glucose electrodes detect the molality of glucose in plasma and whole blood.

It is the activity that determines the direction of chemical processes, transport, etc. and thus provides the clinically more relevant information. Direct reading glucose electrodes consume glucose at a rate proportional to the glucose activity in the sample. The activity equals the molality (mmol glucose per kg water), so results from direct reading glucose electrodes must differ from the conventionally measured glucose concentration. This was observed in 159 whole blood samples which gave higher results from a direct reading glucose electrode than by our conventional method (y = 1.21x - 0.37 mmol/l). However, adjustment for the different water concentration due to salt, plasma proteins, and hemoglobin occupying space, gave results equal to the concentrations (y = 1.00x - 0.28 mmol/l, r = 0.997). Furthermore, results for samples with constant glucose concentration and varying albumin concentration correlated with the albumin concentration (r = 0.989), but not after adjustment for water concentration (r = 0.037, n.s.).

Influence of Age on the Endocrine-metabolic Response to Surgery

The pathogenesis of the increased operative risk in elderly patients is unknown. From a theoretical point of view, a change in endocrine-metabolic response might be involved. In the present study, a battery of hormonal and metabolic variables were measured in eight young and eight elderly healthy males undergoing elective inguinal hernial repair under general anesthesia. Blood was drawn before induction of anesthesia, at skin incision, and one, two, and six hours after skin incision. The findings were: 1) Plasma cortisol increase was significantly higher in elderly than in young controls. 2) Plasma renin level was lower in old age, but renin-aldosterone and electrolyte response patterns were alike in the two groups. 3) Thyroid parameters, in terms of serum T4, serum T3, serum rT3, and T3-resin uptake, responded normally to surgery and showed no age-related differences. 4) The hyperglycemic response was not significantly influenced by age indicating unchanged glycoregulatory mechanisms also verified by determinations of plasma catecholamines, cAMP, and insulin. 5) Blood lymphocyte count was constantly lower in elderly than in young and decreased with time, but the age-related difference was not significant. 6) Blood polymorphonuclear leukocytes showed an increase of the same magnitude in both age groups, although at a significantly slower rate in the elderly. It is concluded that age affects some aspects of the initial endocrine-metabolic response to surgery.

Serum ionized calcium, nephrogenous and total urinary cyclic AMP and urinary phosphate in normal subjects

Total urinary cyclic AMP (UcAMP) and nephrogenous cyclic AMP (NcAMP) were measured in 4, 20 and 24 h urine in forty-eight healthy volunteers. There were no significant differences between 4, 20 and 24 h excretion rate of UcAMP and NcAMP whether it was corrected for the glomerular filtration rate [( UcAMP]GF, [NcAMP]GF), creatinine corrected (UcAMP/Crea)U, or expressed as actual excretion rate (NcAMP,n), nor any sex differences. Mean values +/- one standard deviation (SD) for these parameters: [UcAMP]GF: 30.4 +/- 9.4 nmol/l; 27.7 +/- 7.0 nmol/min; 28.1 +/- 6.9 nmol/l in 4, 20 and 24 h urine, respectively. [NcAMP]GF: 13.4 +/- 8.5 nmol/l; 10.6 +/- 7.7 nmol/l; and 11.1 +/- 7.2 nmol/l in 4, 20 and 24 h urine, respectively. (NcAMP,n): 1.45 +/- 0.90 nmol/min; 1.14 +/- 0.80 nmol/min; 1.17 +/- 0.73 nmol/min in 4, 20 and 24 h urine, respectively, NcAMP accounts for about 40% of UcAMP. A positive correlation was found between plasma cyclic AMP and [UcAMP]GF (r = 0.41, P less than 0.001), whereas this relationship could not be demonstrated between plasma cyclic AMP and [NcAMP]GF (r = -0.008, P greater than 0.1). The calculation of [NcAMP]GF therefore corrects for unsuspected high or low plasma cyclic AMP values, and is therefore the preferred parameter of the PTH effect on the kidney tubular cells. No correlation could be demonstrated between [NcAMP]GF and concentration of ionized calcium in plasma.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased activity of ionised calcium in gall bladder bile in gall stone disease.

The actual activity of ionised calcium (Ca2+) in gall bladder bile determined with an ion-selective electrode was significantly higher in patients with gall stone disease (n = 15) than in patients without gall stones (n = 10) (0.43 mmol/kg v 0.31 mmol/kg; p < 0.05). No change in the Ca2+ activity in any of the gall bladder bile samples was observed during equilibration with CO2. During titration with HCl/NaOH, however, the Ca2+ activity fell with increasing pH in a biphasic manner, with the breaking point occurring at a significantly lower median pH in patients with gall stones than in patients without (pH 7.1 v 8.2; p < 0.0001). The combination of a higher activity of calcium in bile and precipitation of bile salts taking place at a lower pH in patients with gall stone disease than in patients without gall stones suggests a major role for calcium and pH in the pathogenesis of gall stones. Strict anaerobic sampling is not necessary for the measurements of Ca2+ in gall bladder bile, because the Ca2+ was not significantly affected by the changes in pCO2. The metabolic studies suggest, however, that simultaneous measurements of the activity of Ca2+ and pH is important in order to interpret data for the calcium activity in gall bladder bile.

Lack of relationship between serum and gallbladder bile calcium in patients with gallstone disease

BACKGROUNDnRecent studies suggest that alternation in serum calcium influences the level of gallbladder bile ionized calcium (Ca2+). Theoretically, this could increase the risk of calcium precipitation in the gallbladder.nnnMETHODSnWe therefore measured serum and gallbladder bile minerals in patients with gallstones (n = 27) and without (n = 10, controls). The serum samples were taken just prior to induction of anaesthesia and gallbladder bile was aspirated before any manipulation of the gallbladder.nnnRESULTSnThe active molality of Ca2+ in gallbladder bile was not statistically significant different between cases and controls (0.44 +/- 0.16 vs. 0.40 +/- 0.10 mmol/kg), whereas pH was significantly lower (6.94 +/- 0.31 vs. 7.36 +/- 0.28, p < 0.0001) and cholesterol higher (4.37 +/- 2.70 vs. 1.79 +/- 1.33 mmol/l; p < 0.01) in gallbladder bile obtained from cases. Serum Ca2+ at actual pH, magnesium and phosphate were significantly higher among cases than in controls. Gallbladder bile active molality of Ca2+ was significantly correlated with bile total calcium in both groups (r = 0.72; p < 0.001 and r = 0.91; p < 0.001, respectively). In controls only, we observed a positive relationship between serum Ca2+ at actual pH and the active molality of Ca2+ in bile (r = 0.61; p < 0.05).nnnCONCLUSIONnOur study demonstrates that Ca2+ in gallbladder bile does not differ between cases and controls. The lack of correlation between serum and gallbladder bile constituents in cases compared to controls suggests that changes in calcium equilibration between bile and serum in patients with gallstone disease might be of importance for the formation of gallstones.

Parathyroid Hormone and Hypophosphatemia

Excerpt To the editor: It has been suggested that nonrenal hypophosphatemia is associated with decreased sensitivity of renal tubules to parathyroid hormone in rats (1). To our knowledge there are ...