Significance of the changes in plasma amino-acid levels in meningococcal infection

A series of patients with meningococcal infections have been studied and divided in two groups: Group I patients with meningococcal sepsis and group II, those with meningococcal meningitis. Patients in group I presented with more severe encephalopathy, shock, DIC and acute systemic complications. Both groups showed a marked hypoaminoacidemia compared with normal controls (other than for the sulfur containing amino acids and phenylalanine). The concentration of aromatic and basic amino acids, the phenylalanine/tyrosine ratio, the transaminase levels and the negative nitrogen balance were higher in group I patients. The ratio of branched chain to aromatic amino acids was lower in group I. All these differences were statistically significant. The close association between the metabolic derangements and clinical manifestations may help in the understanding of several physiopathological aspects of meningococcal infections.

Intestinal glucose and galactose transport in the cultured gilthead bream (Sparus aurata)

1. Electrical parameters and transepithelial glucose and galactose transport were determined in vitro across anterior and posterior intestine of the culture fish Sparus aurata. 2. Electrical potential difference (PD) and short-circuit current (Isc) were serosa-positive in anterior intestine, while they were serosa-negative or near zero in posterior intestine. 3. Tissue conductance (Gt) was higher in posterior than in anterior intestine. In both parts it was decreased when the Na ion was omitted in mucosal and serosal reservoirs. 4. Addition of glucose or galactose to the mucosal side of intestine caused an increase in PD and Isc in posterior intestine but did not significantly change PD and Isc in anterior intestine. 5. Isotopic flux of glucose and galactose measurements in short-circuit conditions showed a net active glucose and galactose absorption in posterior intestine, while in anterior intestine active transport of glucose or galactose was not observed. 6. The net transport of glucose and galactose in posterior intestine was decreased to zero in the absence of Na in mucosal and serosal reservoirs or in the presence of ouabain (1 mM) in serosal solution.

Effect of theophylline on ion transport in the lizard colon

1. The effect of theophylline on ion transport was examined using an in vitro short-circuited preparation of lizard colon. 2. Theophylline increased short circuit current (Isc) and transmural potential difference (PD). This increase caused by theophylline was accompanied by a small increase in transmural conductance (Gt). 3. Theophylline did not inhibit the absorption of Na+ but reversed Cl- absorption to secretion. This latter effect was due to an increase of the serosal-to-mucosal flux of Cl-. 4. Ion substitution experiments revealed that the effect of theophylline was Na+- and HCO3(-)-dependent and that these ions were required in the bathing solution. 5. These results with lizard colon are compared with those reported for mammalian colon and the mechanism of theophylline-induced Cl- secretion in these epithelia is discussed.

Delayed repair of an acquired posterior septal defect through a right atrial approach

A patient with chronic postinfarction ventricular septal defect located posteriorly is described. The right atrial approach is suggested for these defects and the operative differences between chronic and acute defects are discussed.

Transport of galactose and sodium across lizard duodenum

Electrical parameters and transepithelial Na+ and galactose transport were determined in vitro across isolated duodenum of Lacerta galloti lizard. Electrical potential difference (PD) and short-circuit current (Isc) were dependent on the presence of Na+ in the bathing solutions. PD and Isc were affected by addition of galactose to the mucosal solution. Isotopic flux of Na+ measurements across short-circuited duodenum showed a net active Na+ absorption. The net flux of Na+ (JNa+net) accounted for the observed Isc. Both (JNa+net) and Isc were increased by the addition of galactose 5 mM to the mucosal solution. Isotopic flux galactose measurements in open-circuit conditions showed a net active galactose absorption. The net transport of galactose was decreased to zero in the absence of Na+ in mucosal and serosal reservoirs. Galactose has been used to induce changes in short-circuit current (delta Isc) across intestine. delta Isc was a hyperbolic function of galactose concentration characterized by the parameters Vmax (maximum change in delta Isc) and Km (concentration needed to attain a velocity equal to half the Vmax).

Electrical properties of a Na+-dependent phenylalanine transport in lizard (Lacerta galloti) duodenum

The unidirectional transepithelial fluxes of L-phenylalanine across lizard duodenum were determined in flux chambers. Phenylalanine was preferentially transferred from the mucosal to the serosal fluid. This transport was accompanied by an accumulation of substrate from the mucosal medium into the tissue to a similar level and against a concentration gradient. There was no net movement of phenylalanine when the sodium was substituted by choline. The influx of L-phenylalanine into the epithelial cells of lizard duodenum was examined by incubating slices of intestine in radioactively-labelled solutions of the substrate for 2 min. The steady-state uptake was assessed after similar incubations lasting 45 min. Phenylalanine influx obeys the Michaelis-Menten equation with a Km of 5.1 and is dependent on the presence of sodium ions in the incubation medium. Phenylalanine has been used to induce changes in short-circuit current (delta Isc) across intestine. delta Isc was a hyperbolic function of amino acid concentration characterized by the parameters Jm (maximum change in delta Isc) and Km (concentration needed to attain an delta Isc equal to half the Jm). delta Isc determined Km constants showed good agreement with values obtained from direct measurements of phenylalanine uptake into tissue.

Bioelectric parameters and sodium and chloride fluxes across the intestine of Blennius parvicornis

Simultaneous measurements of the electric potential difference and the short-circuit current intensity were taken, as well as measurements of unidirectional fluxes of sodium and chloride in the posterior intestine of Blennius parvicornis fish. On incubating the tissue in standard Ringer solution, a potential difference of--0.9 mV, a mean net flux of sodium of 2.49 mu Eq/h x cm2 were obtained. In the absence of sodium (choline as substitute), the net chloride flux and the Isc were completely blocked. In the absence of chloride (isocyanate as substitute) the net sodium flux and the Isc were equally blocked. Ouabain lessened the sodium and chloride fluxes in the mucosa-serosa direction to the point of nulling the net fluxes of both ions. The values of the bioelectric parameters were also blocked in the presence of this inhibitor. Acetazolamide did not significantly affect the values of either the unidirectional fluxes or the net fluxes of sodium and chloride. Nor did it affect the values of the bioelectric parameters. A mechanism for the absorption of sodium and chloride is proposed in which these ions enter the cell in a coupled form and in 1:1 proportion, the transport being independent of the bicarbonate ion.

Transmural potential differences and short-circuit current intensity in the posterior intestine of Blennius parvicornis

Simultaneous measurements of the transmural potential difference (PD) and the short-circuit current intensity (Isc) in the posterior intestine of the fish Blennius parvicornis were made in normal Ringer and in solutions of different ionic composition. The ouabain effects on these two parameters were also tested in normal Ringer solution. The absence of K+ from the Ringer solution on both the mucosal and serosal sides has no apparent effect on the PD and Isc within the first 15 min, but it makes them null after 30 min. When Na+ is substituted in both compartments, using Tris as substitute, a serosal negativity increase is initially observed, but it gradually decreases to zero after 30 min of experimentation. Similarly the PD and Isc drop to zero in the absence of Cl- (sulfate as substitute). Ouabain diminishes the serosa negative potential difference to zero after 30 min presenting a lineal relation to the Isc. A likely transport mechanism for Cl- dependent on the Na+ - K+ pump, is discussed.

Comparative studies on the transmural potential difference and the intensity of the short-circuit current between the duodenum and the ileum of pigeon

The transmural potential difference (PD), short circuit current intensity (Isc) and tissue resistance has been studied in duodenum and ileum of pigeon (Columbia livia var domestica) in media of different ionic compositions. When the tissue is incubated in a standard solution, the PD across the duodenum is approximately zero, while across the ileum is 7.2 mV (serosa positive with respect to mucosa). The PD and Isc measurements in duodenum in the absence of sodium on one hand and in the absence of chlorine on the other, reveal the existence of an active sodium absorption from mucosa to serosa, which draws chlorine along in the same direction. When sodium is substituted in the ileon (Tris as substitute), the PD and the Isc show a marked increase in serosa negativity. In the absence of the chloride ion sulphate as substitute) in ileon the PD and the Isc tend to zero, which indicate that the presence of the ion is necessary for the sodium transport.

Preliminary studies on transmural potential and intensity of the short-circuit current in intestine of Gobius maderensis

The electrical difference (PD) and short-circuit current (Isc) across anterior intestine have been studied in vitro with solutions of different ionic composition in Gobius maderensis. 30 minutes after the beginning of the experiment a PD of about 2 mv negative serosa and an Isc of approximately 200 micro A/cm2 were recorded. Omission of sodium (Tris as substitute) from the luminal side or from both sides leads to an increment of 800% in PD more negative serosa together with an increase of 969% in Isc. In the absence of chloride (sulphate as substitute) the PD and Isc decreased and attained constant positive values. When the potassium was omitted from the luminal side or from both sides neither the P nor the Isc changed. These findings corroborate the assumption that active transport of chloride ions from mucosa to serosa is the major factor for transmural PD and account for the short-circuit current in the anterior intestine of Gobius maderensis.

[Oxygen uptake and active transport of glucose by small intestine of lizard Lacerta galloti (author's transl)]

The lizard intestine capability for active transport of D-glucose has been studied in vitro at 30 degrees C. A release of glucose and fructose from intestinal tissue to the medium took place throughout the incubation period. An active transport of glucose against a concentration gradient from the mucosal to the serosal compartment was found, but in a Na+--free medium (Tris as a substitute) this process was strongly inhibited--. The oxygen uptake was 50% higher in the presence of glucose than in its absence.