[Isolation and some properties of the proteinase atroxin from the venom of the snake Bothrops atrox]

A proteolytic enzyme from the venom of Bothrops atrox snake was isolated. It was designed as Atroxin, and three chromatography steps were used to purification: ion exchange chromatography on DEAE-Sephadex A-50 equilibrated with 0.05 M Tris HCl buffer, 1 mM CaCl2 pH 7.4, followed by gel filtration on Sephadex G-50 and Sephadex G-100, respectively, using the same buffer. The enzyme was recovered with a 7.4 folds and 11% of yield. It had a high activity on casein being 7.4 optimus pH. A molecular weight was 19.9 Kd calculated by polyacrilamide gel electrophoresis, and head treatment showed that the enzyme preserves its activity in the range of 37-45 degrees C, while it was decrease when the temperature values were higher. On the other hand, 0.133 mumoles of Ca2+ and Mg2+, and Zn2+ ions (0.266 mumoles) were activators, while EDTA (0.20 mumoles) and sodium azide (0.053 mumoles) were inhibitors. The enzymatic activity was not affected by glicerol (1.33 mumoles) and phenyl methyl sulphonyl fluoride (PSMF) (0.16 mumoles). In addition, iodoacetic acid (0.08 mumoles) was slight inhibitor, but 0.16 mumoles of p-tosyl-1-lysine chloromethyl ketone (TLCK) was activator. Biological assays on mice showed that atroxin produced hemorrhagic and necrosis after 24 h of injection, which was increased by 5 mM calcium chloride.

[Demand for consultations at the Emergency Service of the "Dr. José Horwitz B" Psychiatric Institute in Santiago, Chile: comparison between 1988 and 1994]

BACKGROUND

In the last decade, there have been changes in the prevalence of specific psychiatric disorders.

AIM

To study the diagnoses and demographic features of patients consulting the emergency wards of a public psychiatric hospital in Santiago during 1994 as compared with those of patients consulting in 1988.

MATERIALS AND METHODS

A random sample of 439 patients charts, corresponding to 3% of all consultations during 1994, were analyzed. The results were compared with consultations during 1988, analyzed in a previous study.

RESULTS

During 1994, patients were older, came alone to the emergency wards and consulted during the night with greater frequency than during 1988. In both years psychosis were the main cause of consultation. Compared to 1988, during 1994 there was an increase in the frequency of affective disorders (16 and 12% of all consultations respectively) and substance abuse (15 and 3% respectively).

CONCLUSIONS

The increase in consultations due to affective disorders and substance abuse in 1994 is in accordance with changes in the epidemiological profile of psychiatric disorders in Santiago.

Stimulation of albumin synthesis in rat hepatocytes by ascites from patients with cirrhosis

Hepatocyte growth factor (HGF), identified in ultrafiltered ascites and plasma from patients with cirrhosis, enhances the DNA synthesis in adult rat hepatocytes cultured at low cell density. This study was carried out to investigate the effect of ascites and plasma from patients with cirrhosis on liver-specific functions such as albumin synthesis in adult rat hepatocytes cultured at confluent-cell density. Ultrafiltered ascites from patients with cirrhosis and its ascitic protein, partially purified by fractionation with ammonium sulfate and gel filtration on Sephadex G-200, stimulated albumin synthesis in a dose-dependent manner in the presence of 10(-8), M dexamethasone. This effect was greater than that of 10(-7) M insulin and similar to that of 10(-7) M dexamethasone, but was additive with that of insulin plus dexamethasone. The molecular weight of the ascitic factor was estimated as 100,000 to 150,000, corresponding to that of HGF purified from cirrhotic ascites. Moreover, the partially purified ascitic factor markedly stimulated DNA and protein synthesis in hepatocytes. These findings suggest that the ascitic factor may act as HGF by stimulating hepatocyte DNA and albumin synthesis in a cell density-dependent manner.

Role of Digestive Gland in the Energetic Metabolism of Penaeus setiferus

We determined the role of the digestive gland in the respiratory metabolism of Penaeus setiferus adult males as a step toward proposing a feeding schedule based on the cycle of activity in the digestive gland. We measured pre- and postprandial values for oxygen consumption rate and hemolymph glucose concentrations in live animals, and oxygen consumption rate and glycogen concentration in excised digestive gland. After the animals were fed, which enhanced general metabolic activity, these indices changed. There was a high correlation between the oxygen consumption rate of the animal and the glucose concentration in the hemolymph, and between the oxygen consumption rate by the digestive gland and the glycogen concentration in the digestive gland, all in relation to time after feeding. Correlations support the hypothesis that the energy demand depends upon the metabolic substrate concentration. In this theory, glucose sustains muscle activity (during ingestion of food) and glycogen is the product of the digestive gland during food assimilation. Our observations of metabolic dynamics during the feeding period allowed us to examine the feeding process. The metabolic activity of the digestive gland was highest 6 h after feeding. This could mean that assimilation, having started 2 h after food intake, peaked 6 h after feeding. Eight hours after feeding, the oxygen consumption rate of the digestive gland decreased and fell to values similar to those recorded for animals subjected to 72 h of fasting.

Interventional cardiology in Chile

In Chile the first experiences with cardiac catheterization began very shortly after Forssmann's first studies. Percutaneous coronary balloon angioplasty (PTCA) was first performed in 1982. Despite a progressively great interest and training of physicians in invasive cardiology there are still restrictions in its development. Most private institutions have modern facilities but their caseloads, ever increasing, are still limited because they take care of only 35% of the population. Public institutions are limited because of funding, and some are just developing PTCA. The situation has improved recently because of deals between the private and public systems. Experience with newer devices is even more limited.

Effect of NPPB on chloride (Cl-) transport in distal colon of potassium (K+) adapted rats

Secondary hyperaldosteronism enhances the rate of K secretion in distal colon, at least in part, through the stimulation of Na(+)-K(+)-Cl- cotransport across the basolateral membrane. To maintain a constant intracellular Cl- activity an increase in Cl- transport out of the cell must be assumed. We explored, under amiloride 10(-4) M and short circuited conditions, conductive pathways for Cl- exit in the distal colon of K(+)-adapted rats by means of a putative Cl- channel blocker, NPPB (5-nitro-2(3-phenyl-propylamino-benzoate. Results prior to NPPB showed an increase in JClms after K+ loading from 5.84 +/- 0.66 to 8.33 +/- 0.86 and JClsm from 4.77 +/- 0.55 to 8.16 +/- 0.96 microEq h-1 cm-2 (P < 0.001), when compared with controls. Net fluxes were not different between groups. Luminal NPPB in K+ adaptation resulted in a decrease of JClsm, from 7.85 +/- 1.5 to 6.69 +/- 1.5 microEq h-1 cm-2 (P < 0.05). There were no changes in both unidirectional Cl- fluxes in controls under luminal NPPB and in potential difference (V) and short-circuit current (Isc) under any condition. Finally, K+ adaptation resulted in an increase of luminal cyclic AMP (cAMP) concentration (0.09 +/- 0.02 to 0.20 +/- 0.03 pmol 100 microliters -1, P < 0.005), when compared with control rats. The data may suggest a transcellular recycling of Cl- and an activated NPPB inhibitable serosal to mucosal Cl- pathway on luminal membrane in the K+ adapted state, possibly mediated by an increase in cAMP production.

Water handling in Caco-2 cells: effects of acidification of the medium

Caco-2 cells were cultured on permeable supports. At confluence the minute-by-minute net water movement (Jw) was automatically recorded. Simultaneously, unidirectional [14C]mannitol, 22Na+, and/or 36Cl- fluxes and transepithelial resistances were measured. The water and mannitol permeabilities went progressively down between 9 and 16 days after seeding and then stabilized. In this last condition the hydrostatic permeability coefficient (Phydr) was 2.67 +/- 0.31 cm s-1 while the osmotic permeability coefficient (Posm) was 0.0017 +/- 0.0004 cm s-1. Phydr but not Posm was dependent on the temperature and on the presence of Na+ in the medium. A net secretory Jw was observed 16 days after seeding, in the absence of any osmotic, hydrostatic or chemical gradient. This secretory Jw was associated with net Cl- (1.43 +/- 0.43 muequiv h-1 cm-2) and Na+ (1.05 +/- 0.35 muequiv h-1 cm-2) secretions. Amiloride reduced, in open-circuit conditions, both Na+ and Cl- apical to basal fluxes, thus enhancing the net Na+ and Cl- exit. Acidification of the medium (pH 6.2) reversibly increased water and mannitol permeabilities in 10-day-old cultures. In 16-day-old cultures the same shift in medium pH did not change mannitol permeability, while stimulating water secretion. These results, obtained in the absence of supracellular structures (villae, crypts) and subepithelial components (muscular, vascular and conjunctive tissues) indicate that paracellular and transport-associated water pathways are sensitive to changes in the pH of the medium in Caco-2 cell layers.

[Treatment of mild hypertension with captopril and captopril with hydrochlorothiazide. Impact on blood pressure values and quality of life]

The effects of captopril alone or associated to hydrochlorothiazide on blood pressure and quality of life was studied in 244 hypertensive subjects. After a medication wash out period of 30 days (and 7 additional days when diuretics were used) patients were treated initially with captopril 25 mg b.i.d. (scheme A); if blood pressure was not normalized, hydrochlorothiazide 25 mg o.d. was added (scheme B) and the dose of captopril was increased to 50 mg bid (scheme C) in a stepwise fashion. Sixteen patients (6.6%) were lost from follow up; in the rest a significant reduction of blood pressure was obtained at the end of the treatment period (from 163/98.9 +/- 19.7/3.1 to 143/85 +/- 12.7/6.7 p < 0.05), without changes in cardiac frequency. Using captopril alone, blood pressure was normalized at 15 and 75 days in 62.9 and 70.6% of patients respectively. With captopril plus hydrochlorothiazide blood pressure was normalized in 80.9% of patients. Quality of life improved significantly from of 42.8 +/- 1.7 to 50.7 +/- 15 score points (p < 0.05) secondary effects were observed in 7.4% of patients. It is concluded that captopril alone or associated to hydrochlorothiazide is effective in the treatment of mild hypertension, produces few secondary effects and improves the quality of life.

[Detection of viable myocardium by means of stress test with thallium 201: usefulness of delayed imaging]

Delayed imaging may help detect viable myocardium after stress Thallium scintigraphy. In 22 patients who had sustained myocardial infarction we performed a stress Thallium test followed by imaging after 24 hr. Delayed reperfusion was observed in 57% of segments showing no reperfusion at 4 hr, which is similar to findings reported in the literature. We proposed that delayed imaging should be performed in all patients showing perfusion defects at 4 hr. Even though a better image may be obtained using reinjection of Thallium, delayed imaging may be the technique of choice to reduce the cost of the test.

Water and ion handling in the rat cecum

The minute-by-minute net water movement (Jw) in the rat cecum was correlated with the transepithelial potential difference (PD), short-circuit current (Isc), and the unidirectional Na+, Cl-, and Rb+ fluxes, with the following results. 1) Jw was a linear function of the applied hydrostatic or osmotic transepithelial gradients (hydrostatic permeability coefficiency = 0.164 +/- 0.018 cm/s, n = 13; osmotic permeability coefficient = 0.0014 +/- 0.0002 cm/s, n = 6). 2) A fraction of this absorptive Jw (0.17 +/- 0.03 microliter.min-1.cm-2, n = 13) was independent of the presence of any osmotic, hydrostatic, or chemical gradient. 3) This fraction was Na+ dependent, associated with an amiloride-insensitive PD and net Na+ (2.37 +/- 0.68 mu eq.h-1.cm-2, n = 6) and Cl- influxes (3.45 +/- 1.46 mu eq.h-1.cm-2, n = 6), measured under short-circuit conditions. No net Rb+ movement was detected. 4) The absorptive Jw increased when HCO3- was replaced by tris(hydroxymethyl)aminomethane (Tris+) buffer or Cl- by SO4(2-). A good agreement between the observed and the expected Jw (assuming isosmotic reabsorption) was observed in the absence of HCO3-. 5) The presence of an osmotic but not a hydrostatic transepithelial gradient generated a transepithelial PD. These results show that water movement across the rat cecum in vitro is the result of a combination of hydrostatic-, osmotic-, and transport-associated transfers. Concerning this last driving force, the observed results indicate that the transport-related Jw results from the addition of an absorptive Jw, coupled to a nonelectrogenic NaCl entry, plus a secretory Jw probably coupled to HCO3- secretion.

Water handling in the human distal colon in vitro: role of Na+, Cl- and HCO3-

The minute by minute net water movement (Jw) was measured, in the human distal colon in vitro, simultaneously with the transepithelial potential difference (PD) and short circuit current (SCC) with the following results: (1) An absorptive Jw (+0.36 +/- 0.04 microliters/(min.cm2)) was observed, in 21 cases, when the colon was mounted between two identical standard salines (Na+ 140, Cl- 110, HCO3- 25 mequiv./L) and in the presence of a hydrostatic pressure gradient (delta P) of 13 cm of H2O (mucosal side positive). (2) This absorptive Jw was a linear function of the applied delta P or the imposed osmotic transepithelial gradient (Phydr = 0.22 +/- 0.03 cm/s; Posm = 0.0020 +/- 0.005 cm/s; n = 6). (3) A fraction of this Jw was independent of the presence of any hydrostatic, osmotic or chemical gradient while associated with a serosal side positive and partially amiloride sensitive PD (11.3 +/- 1.8 mV). (4) Both Jw and PD were dependent on the presence of Na+ in the incubating media. (5) Replacement of Cl- by SO(4)2- did not change the absorptive Jw, but increased the observed PD and the transepithelial resistance. (6) HCO3- removal strongly reduced the SCC and PD together with an important increase in Jw. Unexpectedly, other 9 colon fragments spontaneously showed a secretory Jw when mounted between two identical standard salines (-0.55 +/- 0.11 microliters/(min.cm2). In these experiments it was observed that: (7) The tissue moved water against the imposed delta P (13 cm of H2O), while the associated PD (+11.9 +/- 2.1 mV) was similar to the one observed in absorptive fragments. (8) As in the case of absorptive preparations, PD, SCC and the transport associated Jw fell to zero in the absence of Na+. (9) When SO(4)2- replaced Cl-, secretory Jw reversed to absorptive Jw, together with an increase in PD and resistance. In both absorptive and secretory preparations it was finally observed that: (10) norepinephrine (5 x 10(-6) M) decreased SCC and increased the absorptive Jw in a tightly parallel manner (half-times for each response: SCC = 11.4 +/- 2.1 min; Jw = 11.4 +/- 2.0 min, n = 4) and (11) 8-Br cyclic AMP (10(-3) M) increased SCC while simultaneously decreasing the absorptive Jw. It is concluded that the observed Jw in the distal human colon in vitro results from the complex addition of osmotic, hydrostatic and transport associated driving forces. The transport-associated Jw has absorptive and secretory components.(ABSTRACT TRUNCATED AT 400 WORDS)

[The assessment of myocardial perfusion with thallium-201 in patients with a complete left His bundle-branch block]

Thallium-201 myocardial scintigraphy was used to evaluate coronary perfusion in 20 patients with left bundle branch block suspected of having coronary artery disease. Contemporary coronary arteriography was performed in 9 of these patients. Sensitivity and specificity of the method was similar to that obtained in patients without LBBB. A false positive results indicated ischemia of the interventricular septal region in a patient with normal coronary arteries, a known limitation of the method.

[Myocardial perfusion during exercise and rest in coronary patients. Evaluation with a thallium 201 analog (isonitrile-technetium 99 m)]

Isonitrile-technetium, a Thallium 201 analog, was used for myocardial perfusion imaging in 12 patients with known coronary heart disease. 10-40 mCu of the isotope were injected at maximal effort during a Bruce stress test. Imaging was performed using 3 projections immediately after exercise and 24 hr later, using a gamma camera attached to a computer. Myocardial necrosis was detected with a sensitivity of 89% and specificity of 63%. Corresponding figures for stress induced ischemia were 89% and 100%. Accurate localization of ischemia or necrosis was obtained in 70% of all cases, improving to 100% in cases of total artery occlusion. These results, similar to those reported in the literature, encourage the use of Tc labeled isonitrile for myocardial perfusion imaging whenever Thallium 201 is difficult to obtain.

Isolation and characterization of a fibrinogen-clotting enzyme from venom of the snake, Lachesis muta muta (Peruvian bushmaster)

A fibrinogen-clotting enzyme from the venom of the Peruvian bushmaster snake was purified to homogeneity by gel filtration on Sephadex G-100 followed by DEAE-cellulose ion-exchange chromatography using a linear ionic strength gradient with NaCl. The specific activity of the enzyme was 866 NIH U/mg, representing a 55-fold purification, with a recovery of 45%. The amino acid composition was Asx30, Thr14, Ser15, Glx33, Pro23, Gly22, Ala15, Val22, Cys18, Met3, Ile18, Leu23, Tyr2, Phe13, His8, Lys11, Arg11. The total carbohydrate content was 13.4%, comprised of 3.4% hexose, 8.7% hexosamine and 1.3% sialic acid. The enzyme was active against the synthetic amide substrate alpha-N-benzoyl-DL-arginine-p-nitroanilide (BAPNA) and against the ester substrates alpha-N-benzoyl-L-arginine ethyl ester (BAEE) and tosyl-L-arginine methyl ester (TAME). Kinetic parameters for TAME esterolysis were: Vmax, 135 mumoles/min/mg and Km, 2.5 x 10(-4) M. The pH optimum was 8.0. Vmax for BAPNA amidolysis was 0.363 mumoles/min/mg and Km, 7.5 x 10(-5) M. Enzyme activity was reduced by diethylpyrocarbonate and by photo-oxidation, suggesting that the enzyme is a serine protease with a histidine residue involved in the active site. The enzyme released fibrinopeptide A rapidly from purified human fibrinogen and fibrinopeptide B more slowly. Factor XIII was not activated and the clotting activity was not inhibited by heparin. A dose of 50 micrograms/kg brought about defibrinogenation in anaesthetized rats but rabbits were unaffected. A dose of 80 micrograms/kg defibrinogenated conscious rats after 5 hr. There were no hypotensive or haemorrhagic effects.

Left ventricular function in chronic anemia: evidence of noncatecholamine positive inotropic factor in the serum

The enhanced left ventricular (LV) performance observed in anemia has been attributed to changes in preload and afterload. Whether there is a concomitant increase in contractility is controversial. Seventeen patients with chronic anemia (hematocrit range 17 to 30%) and 17 control subjects, matched by age and sex, were studied. In 10 patients and 10 control subjects (group I), a noninvasive evaluation of LV function through M-mode echocardiography and cuff blood pressure recording was performed. In patients with anemia, stroke volume increased 43% (p less than 0.01), fractional shortening 21% (p less than 0.001), and mean rate of circumferential shortening 32% (p less than 0.001). In patients with anemia, end-systolic stress decrease 27% (p less than 0.05) and diastolic blood pressure 21% (p less than 0.001). The effect of serum from these patients and control subjects on the development of isometric tension by isolated cat papillary muscles was assessed compared with the basal (Ringer-Locke bath) values. Anemia serum increased maximal developed tension 21% and maximal rate of tension development 20% relative to basal levels. These changes were significantly higher (p less than 0.001) than the increases produced by control serum (8% and 7%, respectively). In the 7 patients with anemia in group II and their matched controls, the in vitro isometric tension characteristics were assessed before and after blocking beta adrenoreceptors with propranolol, 10(-6) M. The observed increase in the developed tension persisted after beta blockade, as well as the enhancement of the maximal rate of tension development. Plasma catecholamine levels in this group II were within the normal range.(ABSTRACT TRUNCATED AT 250 WORDS)