Retrograde autologous priming for cardiopulmonary bypass: a safe and effective means of decreasing hemodilution and transfusion requirements

OBJECTIVES

The obligatory hemodilution resulting from crystalloid priming of the cardiopulmonary bypass circuit represents a major risk factor for blood transfusion in cardiac operations. We therefore examined whether retrograde autologous priming of the bypass circuit would result in decreased hemodilution and red cell transfusion.

METHODS

Sixty patients having first-time coronary bypass were prospectively randomized to cardiopulmonary bypass with or without retrograde autologous priming. Retrograde autologous priming was performed at the start of bypass by draining crystalloid prime from the arterial and venous lines into a recirculation bag (mean volume withdrawal: 880 +/- 150 ml). Perfusion and anesthetic techniques were otherwise identical for the two groups. The hematocrit value was maintained at a minimum of 16% and 23% during and after cardiopulmonary bypass, respectively, in all patients. Patients were well matched for all preoperative variables, including established transfusion risk factors. Subsequent hemodynamic parameters, pressor requirements, and fluid requirements were equivalent in the two groups.

RESULTS

The lowest hematocrit value during cardiopulmonary bypass was 22% +/- 3% versus 20% +/- 3% in patients subjected to retrograde autologous priming and in control patients, respectively (p = 0.002). One (3%) of 30 patients subjected to retrograde autologous priming had intraoperative transfusion, and seven (23%) of 30 control patients required transfusion during the operation (p = 0.03). The number of patients receiving any homologous red cell transfusions in the two groups during the entire hospitalization was eight of 30 (27%; retrograde autologous priming) versus 16 of 30 (53%; control) (p = 0.03).

CONCLUSIONS

These data suggest that retrograde autologous priming is a safe and effective means of significantly decreasing hemodilution and the number of patients requiring red cell transfusion during cardiac operations.

Comprehensive multimodality blood conservation: 100 consecutive CABG operations without transfusion

BACKGROUND

Despite the recent introduction of a number of technical and pharmacologic blood conservation measures, bleeding and allogeneic transfusion remain persistent problems in open heart surgical procedures. We hypothesized that a comprehensive multimodality blood conservation program applied algorithmically on the basis of bleeding and transfusion risk would provide a maximum, cost-effective, and safe reduction in postoperative bleeding and allogeneic blood transfusion.

METHODS

One hundred consecutive patients undergoing coronary artery bypass grafting were prospectively enrolled in a risk factor-based multimodality blood conservation program (MMD group). To evaluate the relative efficacy and safety of this comprehensive approach, comparison was made with a similar group of 90 patients undergoing coronary artery bypass grafting to whom the multimodality blood conservation program was not applied but in whom an identical set of transfusion guidelines was enforced (control group). To evaluate the cost effectiveness of the multimodality program, comparison was also made between patients in the MMD group and a consecutive series of contemporaneous, diagnostic-related group-matched patients.

RESULTS

One hundred consecutive patients in the MMD group underwent coronary artery bypass grafting without allogeneic transfusion. This compared favorably with the control population in whom a mean of 2.2 +/- 6.7 units of allogeneic blood was transfused per patient (34 patients [38%] received transfusion). In addition, the volume of postoperative blood loss at 12 hours in the control group was almost double that of the MMD group (660 +/- 270 mL versus 370 +/- 180 mL [p < 0.001]). Total costs for the MMD group in each of the three major diagnostic-related groups were equivalent to or significantly less than those in the consecutive series of diagnostic-related group-matched patients.

CONCLUSIONS

Comprehensive risk factor-based application of multiple blood conservation measures in an optimized, integrated, and algorithmic manner can significantly decrease bleeding and need of allogeneic transfusion in coronary artery bypass grafting in a safe and cost-effective manner.

Inhibition of endosome function in CHO cells bearing a temperature-sensitive defect in the coatomer (COPI) component epsilon-COP

Recent evidence has suggested that subunits of the coatomer protein (COPI) complexes are functionally associated with endosomes in mammalian cells. We now provide genetic evidence that COPI plays a role in endocytosis in intact cells. The ldlF mutant CHO cell line bears a temperature-sensitive defect in the COPI subunit epsilon-COP. In addition to exhibiting conditional defects in the secretory pathway, we find that the cells are also defective at mediating endosome-associated functions. As found for cells microinjected with anti-COPI antibodies, ldlF cells at the restrictive temperature could not be infected by vesicular stomatitis (VSV) or Semliki Forest virus (SFV) that require delivery to acidic endosomes to penetrate into the cytosol. Although there was no temperature-sensitive defect in the internalization of receptor-bound transferrin (Tfn), Tfn recycling and accumulation of HRP were markedly inhibited at the restrictive temperature. Sorting of receptor-bound markers such as EGF to lysosomes was also reduced, although delivery of fluid-phase markers was only partially inhibited. In addition, lysosomes redistributed from their typical perinuclear location to the tips of the ldlF cells. Mutant phenotypes began to emerge within 2 h of temperature shift, the time required for the loss of detectable epsilon-COP, suggesting that the endocytic defects were not secondary to a block in the secretory pathway. Importantly, the mutant phenotypes were also corrected by transfection of wild-type epsilon-COP cDNA demonstrating that they directly or indirectly reflected the epsilon-COP defect. Taken together, the results suggest that epsilon-COP acts early in the endocytic pathway, most likely inhibiting the normal sorting and recycling functions of early endosomes.

Long-term regulation of contractility and calcium current in smooth muscle

Longitudinal smooth muscle strips from guinea pig ileum were cultured in vitro for 5 days, and the relationship between extracellular Ca2+ and force in high-K+ medium was evaluated. In strips cultured with 10% fetal calf serum (FCS), this relationship was shifted to the right (50% effective concentration changed by 2-3 mM) compared with strips cultured without FCS. The shift was prevented by inclusion of verapamil (1 microM) during culture and mimicked by ionomycin in the absence of FCS. The intracellular Ca2+ concentration ([Ca2+]i) during stimulation with high-K+ solution or carbachol was reduced after culture with FCS, whereas the [Ca2+]i-force relationship was unaffected. Cells were isolated from cultured strips, and whole cell voltage-clamp experiments were performed. Maximum inward Ca2+ current (10 mM Ba2+), normalized to cell capacitance, was almost three times smaller in cells isolated from strips cultured with FCS. Culture with 1 microM verapamil prevented this reduction. These results suggest that increased [Ca2+]i during culture downregulates Ca2+ current density, with associated effects on contractility.

Intracerebroventricular transplantation of embryonic neuronal tissue from inflammatory resistant into inflammatory susceptible rats suppresses specific components of inflammation

To more directly define the role of central nervous system factors in susceptibility to peripheral inflammatory disease, we examined the effect of intracerebroventricular transplantation of neuronal tissue from inflammatory resistant into inflammatory susceptible rats on subcutaneous carrageenan-induced inflammation (a measure of innate immunity), and on the relative percentage of naive and memory T helper cells in peripheral blood (a measure of the anamnestic immune response). Female inflammatory disease susceptible Lewis (LEW/N) rats transplanted with hypothalamic tissue from inflammatory resistant Fischer (F344/N) rats exhibited > 85% decrease in carrageenan inflammation compared to naive LEW/N rats, LEW/N rats transplanted with F344/N spinal cord, or sham-operated animals. LEW/N rats transplanted with LEW/N hypothalamic tissue exhibited > 50% decrease in carrageenan inflammation. In contrast, intracerebroventricular transplantation of neuronal tissue did not affect the characteristically twofold higher percentage of naive versus memory T helper cells in LEW/N rats, suggesting that the central nervous system (CNS) and hypothalamus play a greater role in the innate inflammatory response than in the acquired immune processes. Grafted tissue survived well and did not show extensive gliosis or inflammation. Compared to naive LEW/N rats, LEW/N rats transplanted with F344/N or LEW/N hypothalamic tissue expressed significantly greater hypothalamic corticotropin releasing hormone mRNA. LEW/N rats transplanted with F344/N hypothalamic tissue also showed significant increases in plasma corticosterone responses to lipopolysaccharide. These data indicate that intracerebroventricular transplantation of fetal hypothalamic tissue from inflammatory resistant into inflammatory susceptible rats suppresses peripheral inflammation partially through hypothalamic factors. These findings have implications for understanding the contribution of specific neuronal tissue in regulation of components of the immune/inflammatory response and in susceptibility to inflammatory disease. Furthermore, this model could be used in the development of potential new treatments for inflammatory/autoimmune diseases aimed specifically at sites within the CNS.

Ectopic pituitary adenoma in the sphenoid causing Nelson's syndrome

An ectopic functioning pituitary in the sphenoid is an extremely rare occurrence, and even rarer is pituitary adenoma causing symptoms of Nelson's syndrome. A case is presented of a young female diagnosed and treated in our clinic. The only functioning hypophyseal tissue was detected inside the sphenoid, as the pituitary gland had been radiated because of Cushing's syndrome 10 years before and imaging studies revealed an empty sella.

Intravenous oxytocin in patients undergoing elective cesarean section

The objective of this study was to compare four different doses of oxytocin to determine its minimal effective dose during elective cesarean section. A prospective, double-blind, randomized study was undertaken in 40 healthy term parturients presenting for elective cesarean section under regional anesthesia. Subjects were assigned to one of four groups. Group I received 5 IU, Group II 10 IU, Group III 15 IU, and Group IV 20 IU of oxytocin after clamping of the umbilical cord. Uterine tone was assessed by palpation on a linear analog scale (LAS) of 0 to 10 (0 = completely atonic, 10 = fully contracted) at 5, 10, 15 and 20 min after the start of oxytocin infusion. Estimated blood loss (EBL) and the difference in pre- and postoperative hematocrit (delta Hct) were also recorded. At alpha = 0.05, the study design had a power of 95% to detect a 25% difference in the LAS between the four groups. There were no differences in the uterine tone in the four groups at any of the four intervals. EBL and delta Hct were similar in all four groups. There appears to be no benefit in terms of degree of uterine contraction and amount of blood loss to administering more than 5 IU of intravenous oxytocin to term parturients undergoing elective cesarean section with a neuraxial block.

Identification of a new sigmaB-controlled gene, csbX, in Bacillus subtilis

We have identified a new member, csbX, of the general stress regulon controlled by sigmaB in Bacillus subtilis. As with other members of the sigmaB regulon csbX is expressed during the stationary phase of cell growth and inactivation of this gene produces no obvious phenotype during cell growth or early development. csbX lies uspstream from the sporulation gene bofC which is co-transcribed during stationary phase.

Expression of the Bacillus subtilis spoIVB gene is under dual sigma F/sigma G control

The expression of the Bacillus subtilis spoIVB gene, which encodes a developmental cell-cell signalling molecule, has been characterized. In some conditions, this gene can be transcribed by RNA polymerase associated with either sigma F or sigma G, in contrast to previous studies implying exclusive control by sigma G. However, during sporulation, only sigma G directs significant levels of spoIVB expression.

A comparison of the Acute Physiology and Chronic Health Evaluation (APACHE) II score and the Trauma-Injury Severity Score (TRISS) for outcome assessment in intensive care unit trauma patients

OBJECTIVE

To assess the ability of the Acute Physiology and Chronic Health Evaluation (APACHE II) system and Trauma-Injury Severity Scoring (TRISS) system in predicting group mortality in intensive care unit (ICU) trauma patients.

DESIGN

Prospective study.

SETTING

A Canadian adult trauma tertiary referral hospital.

PATIENTS

Consecutive trauma patients admitted to the medical-surgical ICU or the neurosurgical ICU.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

For each patient, demographic data, mechanism of injury, and surgical status were collected. Revised Trauma Scores and Injury Severity Scores were calculated from emergency room and operative data. The APACHE II score was calculated based on the data from the first 24 hrs of ICU admission. The probability of death was calculated for each patient based on the APACHE II and TRISS equations. The ability to predict group mortality for APACHE II and TRISS was assessed by receiver operating characteristic curve analysis, two by two decision matrices, and calibration curve analysis. Four hundred seventy trauma patients were admitted to the ICU. Sixty-three (13%) patients died and 407 (87%) survived. There were significant differences between survivors and nonsurvivors in age, Glasgow Coma Scale, Revised Trauma Score, Injury Severity Score, and APACHE II score. By receiver operating characteristic curve analysis, the areas under the curves (+/- SEM) of APACHE II and TRISS were 0.92 +/- 0.02 and 0.89 +/- 0.02, respectively. Using two by two decision matrices with a decision criterion of 0.5, the sensitivities, specificities, and percentages correctly classified were 50.8%, 97.3%, and 91.1%, respectively, for APACHE II, and 50.8%, 97.1%, and 90.9%, respectively, for TRISS. From the calibration curves, the r2 value was .93 (p = .0001) for APACHE II and .67 (p = .004) for TRISS.

CONCLUSIONS

Both APACHE II and TRISS scores were shown to accurately predict group mortality in ICU trauma patients. APACHE II and TRISS may be utilized for quality assurance in ICU trauma patients. However, neither APACHE II nor TRISS provides sufficient confidence for prediction of outcome of individual patients.

Triiodothyronine therapy lowers the incidence of atrial fibrillation after cardiac operations

BACKGROUND

Cardiopulmonary bypass results in a euthyroid sick state, and recent evidence suggests that perioperative triiodothyronine (T3) supplementation may have hemodynamic benefits. In light of the known effects of thyroid hormone on atrial electrophysiology, we investigated the effects of perioperative T3 supplementation on the incidence of postoperative arrhythmias.

METHODS

One hundred forty-two patients with depressed left ventricular function (ejection fraction < 0.40) undergoing coronary artery bypass grafting were randomized to either T3 or placebo treatment groups in a prospective, double-blind fashion. Triiodothyronine was administered as a 0.8 micrograms/kg intravenous bolus at the time of aortic cross-clamp removal followed by an infusion of 0.113 micrograms.kg-1.h-1 for 6 hours. Patients were monitored for the development of arrhythmias during the first 5 postoperative days.

RESULTS

The incidence of sinus tachycardia and ventricular arrhythmias were similar between groups. Triiodothyronine-treated patients had a lower incidence of atrial fibrillation (24% versus 46%; p = 0.009), and fewer required cardioversion (0 versus 6; p = 0.012) or anticoagulation (2 versus 10; p = 0.013) during hospitalization. Six patients in the T3 group versus 16 in the placebo group required antiarrhythmic therapy at discharge (p = 0.019).

CONCLUSIONS

Perioperative T3 administration decreased the incidence and need for treatment of postoperative atrial fibrillation.

Intracerebroventricularly transplanted embryonic neuronal tissue from inflammatory-resistant F344/N rats decreases acoustic startle responses in inflammatory-susceptible LEW/N rats

Recently, we have shown that intracerebral transplantation of fetal F344/N hypothalamic tissue into LEW/N rats converts the LEW/N inflammatory-susceptible phenotype into an inflammatory-resistant phenotype in LEW/N hosts. Because LEW/N rats also exhibit relatively high acoustic startle responses (ASRs) compared to F344/N rats, in the present study we examined the effects on ASR of transplantation of F344/N hypothalamic tissue into the third ventricle of LEW/N rats. Dissected neuronal tissue from F344/N rats (Day E15-16) was implanted into the third ventricle of LEW/N rats. After 4 wk of postoperative survival, the animals' responses to acoustic startle stimuli were tested. Compared to naive and sham-operated animals, LEW/N rats transplanted with hypothalamic tissue exhibited significant decreases in ASR amplitudes. A similar decrease in ASR amplitude was observed in the group of LEW/N rats transplanted with embryonic striatal tissue. Our results indicate that the third ventricular neuronal grafts may modulate behavioral responses in the LEW/N rats. Although the mechanism of this effect is unknown, these studies suggest that intracerebral neuronal transplantation is a viable method with which to explore mechanisms of behavioral, neuroendocrine, and inflammatory response associations.

Age-related effects of aluminum ingestion on brain aluminum accumulation and behavior in rats

Both aluminum and aging have been associated with neurobehavioral changes in mammals. This study assessed in young (21 day old), adult (8 months), and old rats (16 months) the effects of prolonged aluminum ingestion on open-field activity and passive-avoidance conditioning. Aluminum was administered in drinking water as aluminum nitrate at doses of 0, 50, and 100 mg Al/kg/day over a 6.5 month period. There were no aluminum effects on the horizontal and vertical activity in an open-field, or in passive-avoidance learning in any group. On the other hand, measurement of aluminum concentrations in a number of brain regions indicated that the olfactory bulb and the rhachidical bulb were the regions with the highest aluminum levels, while the cortex and the thalamus were the cerebral regions showing the lowest aluminum content. For most brain regions analyzed the highest aluminum concentrations were found in young rats, which would indicate that early stages of the life cycle must be considered for enhanced brain aluminum accumulation.

The estrogen antagonist tamoxifen inhibits carrageenan induced inflammation in LEW/N female rats

Carrageenan induces a measurable inflammatory response in susceptible animals, and mature females are more responsive to carrageenan, than males. In the present study, we tested whether the estrogen antagonist tamoxifen influences carrageenan-induced inflammatory responses. Female LEW/N rats were treated with tamoxifen and compared to a control group of animals injected with vehicle. Tamoxifen significantly reduced estrous phase of estrous cycle during treatment, consistent with its functional anti-estrogen effects. Moreover, tamoxifen significantly decreased exudate volume but did not significantly influence relative white blood cell counts in the exudate. Interestingly, tamoxifen induced differential dose-dependent alterations in peripheral blood lymphocyte subpopulations. Low dose of tamoxifen increased CD25 cells. The high tamoxifen dose significantly increased CD8 blood lymphocytes counts. Our data indicate that tamoxifen treatment decreases carrageenan-induced inflammatory response in female LEW/N rats and suggest therefore that this inflammatory response is, at least in part, estrogen related. Moreover, our results suggest a possible role for tamoxifen in treatment of inflammatory disorders.

Intracerebroventricularly Transplanted Embryonic Neuronal Tissue from Inflammatory-Resistant F344/N Rats Decreases Acoustic Startle Responses in Inflammatory-Susceptible Lew/N Rats

Recently, we have shown that intracerebral transplantation of fetal F344/N hypothalamic tissue into LEW/N rats converts the LEW/N inflammatory-susceptible phenotype into an inflammatory-resistant phenotype in LEW/N hosts. Because LEW/N rats also exhibit relatively high acoustic startle responses (ASRs) compared to F344/N rats, in the present study we examined the effects on ASR of transplantation of F344/N hypothalamic tissue into the third ventricle of LEW/N rats. Dissected neuronal tissue from F344/N rats (Day E15-16) was implanted into the third ventricle of LEW/N rats. After 4 wk of postoperative survival, the animals' responses to acoustic startle stimuli were tested. Compared to naive and sham-operated animals, LEW/N rats transplanted with hypothalamic tissue exhibited significant decreases in ASR amplitudes. A similar decrease in ASR amplitude was observed in the group of LEW/N rats transplanted with embryonic striatal tissue. Our results indicate that the third ventricular neuronal grafts may modulate behavioral responses in the LEW/N rats. Although the mechanism of this effect is unknown, these studies suggest that intracerebral neuronal transplantation is a viable method with which to explore mechanisms of behavioral, neuroendocrine, and inflammatory response associations.

Stereoselective metabolic pathways of ketoprofen in the rat: incorporation into triacylglycerols and enantiomeric inversion

The enantiomeric bioinversion of ketoprofen (KP) enantiomers and their incorporation into triacylglycerols were investigated in the rat (1) in vitro, using liver homogenates, subcellular fractions, and hepatocytes, and (2) in vivo, in different tissue samples after oral administration of the radiolabelled compounds. In liver homogenates or subcellular fractions, the enantiomer (S)-ketoprofen (S-KP) was recovered unchanged, whereas (R)-ketoprofen (R-KP) was partially converted into its Coenzyme A (CoA) thioester and inverted to S-KP. Both processes occurred mainly in the mitochondrial fraction. This supports the mechanism of inversion via stereoselective formation of CoA thioester of R-KP, already described for other non-steroidal anti-inflammatory drugs. Incorporation into triacylglycerols was detected after incubation with intact hepatocytes in the presence of added glycerol. The process was stereoselective for R-KP vs. S-KP (covalently bound radioactivity 26,742 +/- 4,665 dpm/10(6) cells vs. 6,644 +/- 3,179 dpm/10(6) cells, respectively). However, no incorporation was found in liver samples after oral administration of either R-KP or S-KP. On the contrary, in adipose tissue samples a significant and stereoselective formation of hybrid triacylglycerols was observed: 11,076 +/- 2,790 dpm.g-1 for R-KP vs. 660 +/- 268 dpm.g-1 for S-KP. The incorporated R/S ratio, higher in adipose tissue (R/S = 17) than in hepatocytes (R/S = 4), indicates that fat may be the main tissue store for the xenobiotic R-KP in rats.

Thyroid hormone treatment after coronary-artery bypass surgery

BACKGROUND

Thyroid hormone has many effects on the cardiovascular system. During and after cardiopulmonary bypass, serum triiodothyronine concentrations decline transiently, which may contribute to postoperative hemodynamic dysfunction. We investigated whether the perioperative administration of triiodothyronine (liothyronine sodium) enhances cardiovascular performance in high-risk patients undergoing coronary-artery bypass surgery.

METHODS

We administered triiodothyronine or placebo to 142 patients with coronary artery disease and depressed left ventricular function. The hormone was administered as an intravenous bolus of 0.8 microgram per kilogram of body weight when the aortic cross-clamp was removed after the completion of bypass surgery and then as an infusion of 0.113 microgram per kilogram per hour for six hours. Clinical and hemodynamic responses were serially recorded, as was any need for inotropic or vasodilator drugs.

RESULTS

The patients' preoperative serum triiodothyronine concentrations were normal (mean [+/- SD] value, 81 +/- 22 ng per deciliter [1.2 +/- 0.3 nmol per liter]), and they decreased by 40 percent (P < 0.001) 30 minutes after the onset of cardiopulmonary bypass. The concentrations in patients given intravenous triiodothyronine became supranormal and were significantly higher than those in patients given placebo (P < 0.001). However, the concentrations were once again similar in the two groups 24 hours after surgery. The mean postoperative cardiac index was higher in the triiodothyronine group (2.97 +/- 0.72 vs. 2.67 +/- 0.61 liters per minute per square meter of body-surface area, P = 0.007), and systemic vascular resistance was lower (1073 +/- 314 vs. 1235 +/- 387 dyn.sec.cm-5, P = 0.003). The two groups did not differ significantly in the incidence of arrhythmia or the need for therapy with inotropic and vasodilator drugs during the 24 hours after surgery, or in perioperative mortality and morbidity.

CONCLUSIONS

Raising serum triiodothyronine concentrations in patients undergoing coronary-artery bypass surgery increases cardiac output and lowers systemic vascular resistance, but does not change outcome or alter the need for standard postoperative therapy.

Toxicology of vanadium compounds in diabetic rats: the action of chelating agents on vanadium accumulation

The possible use of vanadium compounds in the treatment of diabetic patients is now being evaluated. However, previously to establish the optimal maximum dose for diabetes therapy, it should be taken into account that vanadium is a highly toxic element to man and animals. The toxic effects of vanadium are here reviewed. The tissue vanadium accumulation, which would mean an additional risk of toxicity following prolonged vanadium administration is also discussed. Recently, it has been shown that coadministration of vanadate and TIRON, an effective chelator in the treatment of vanadium intoxication, reduced the tissue accumulation of this element, decreasing the possibility of toxic side effects derived from chronic vanadium administration without diminishing the hypoglycemic effect of vanadium. However, previously to assess the effectiveness of this treatment in diabetic patients, a critical reevaluation of the antidiabetic action of vanadium and its potential toxicity is clearly needed.

Cytoplasmic coat proteins involved in endosome function

Endosomes are intermediates for a complex series of sorting and transport events that occur during receptor-mediated endocytosis. These involve the recognition of targeting determinants on the cytoplasmic domains of many membrane proteins as well as the formations of specific transport vesicles. Accordingly, endosome function is likely to be governed by the regulated assembly of cytoplasmic coat complexes. We have found that, in vitro, endosomes recruit a characteristic set of cytoplasmic proteins in a GTP gamma S-stimulated and brefeldin A-sensitive fashion. Among these are members of the COP-I and ARF families of coat proteins. In addition, endosomes were also found to assemble distinct, clathrin-like coats. Since microinjection of antibodies to beta-COP inhibits the entry of enveloped viruses via the endocytic pathway, it is apparent that the recruitment of COP-I or COP-I-related proteins plays an important role in the function of endosomes in intact cells.

Impact of patient-controlled analgesia on required nursing time and duration of postoperative recovery

BACKGROUND AND OBJECTIVES

Patient-controlled analgesia (PCA) offers effective postoperative pain management. However, the evidence of economic benefits associated with its use is lacking. Although suggestive, the potential economic advantages of PCA in saving nursing time and shortening hospital stay need objective documentation.

METHODS

This study compared the effects of morphine administered by PCA systems with intramuscular (i.m.) morphine injection on patient analgesic response, satisfaction, nursing time requirements, and postoperative recovery in 23 patients undergoing "open" cholecystectomy and 44 patients undergoing lumbar laminectomy and bony fusion. After the operation, patients in the PCA group received 1.5-2 mg morphine with a lockout of 5-10 minutes on demand, whereas those in the i.m. group received 0.15-0.2 mg/kg every 4 hours on demand. Visual analog scale (VAS) pain scores and satisfaction scores were evaluated at 4-hour intervals while nursing time spent on both analgesia-related and non-analgesia-related activities was recorded continuously by a team of independent observers on the ward. Recovery time profile for the return of bowel function, activities of daily living, ambulation without support, and length of hospital stay was also recorded.

RESULTS

It was found that morphine consumption, VAS, and satisfaction scores were similar in both PCA and i.m. treatment groups following both types of surgery. However, the delay in nurse response to i.m. morphine request ranged from 27.2 +/- to 42.1 +/- 11.8 minutes. The demand of nursing time on analgesia administration was less with PCA. The magnitude of time saving was 10 min/patient/d in cholecystectomy patients and 13 min/patient/d in laminectomy patients. The speed of postoperative patient recovery was similar between the two analgesia groups. Length of hospital stay following cholecystectomy was shorter--92.0 +/- 5.9 hours with PCA versus 128.6 +/- 22.2 hours with i.m. (not statistically significant)--whereas that following laminectomy was not different.

CONCLUSIONS

Data in this study have demonstrated some beneficial effects of PCA on nursing time requirements when it was used following cholecystectomy and lumbar laminectomy at the University of Toronto: however, the magnitude of these benefits was less than previously reported. The effects of PCA on postoperative recovery and hospital stay, however, were not significantly different from i.m. therapy.

Effects of some chelating agents on urinary copper excretion by the rat

In order to estimate the potential advantages of new chelating agents which can enhance copper excretion in the chronic copper intoxication arising in Wilson's disease, the relative ability of none chelating agents to induce the urinary excretion of copper was compared with that of D-penicillamine (DPA) and triethylenetetramine.2HCl (TRIEN), all given ip at 1 mmol/kg to male Sprague-Dawley rats. The compounds examined were as follows: tris(2-aminoethyl)-amine.3HCl (TREN), tetraethylenepentamine.5HCl (TETREN), pentaethylenehexamine.6HCl (PENTEN), 1,4,7,11-tetraazaundecane.4HCl (TAUD), 1,5,8,12-tetraazadodecane.4HCl (TADD), 1-N-benzyltriethylenetetramine.4HCl (BzTT), 4,7,10,13-tetraazatridecanoic acid.2H2SO4 (TTPA), 1,10-bis(2-pyridylmethyl)-1,4,7,10-tetraazadecane.4HCl (BPTETA), and N,N-bis(2-pyridylmethyl)-4-(aminomethyl)benzoic acid (4ABA). Of these, BzTT, TTPA, and 4ABA are new chelating agents not previously reported. The factors by which these chelating agents enhanced copper excretion over control (untreated) levels were as follows: DPA, 7.2; TREN, 1.6; TRIEN, 4.0; TETREN, 10.1; PENTEN, 7.8; TAUD, 7.8; TADD, 2.6; TTPA, 5.6; BzTT, 1.8; and 4ABA, 5.5. The results indicate that it may well be possible to develop additional chelating agents which are equal or superior to those now used in the treatment of Wilson's disease, as well as structural types whose immunological properties may be significantly different from DPA or TRIEN, the compounds currently used in the clinic for this disorder.

Effects of polyamines on voltage-activated calcium channels in guinea-pig intestinal smooth muscle

Effects of polyamines on the spontaneous mechanical and electrical activity of guinea-pig intestinal smooth muscle were studied. Spermine and spermidine inhibited action potential generation and contractions, while putrescine had no effect. Single smooth muscle cells were isolated from the longitudinal muscle layer of the guinea-pig ileum. Whole-cell voltage-clamp experiments were carried out to investigate the effects of polyamines on current through voltage-activated Ca2+ channels. Spermine and spermidine (0.1-1 mM) reduced the inward current in a concentration-dependent manner. Spermine blocked current activated by the dihydropyridine agonist BAY K 8644 (1 microM), whereas no additional inhibition by spermine was seen after blockage of dihydropyridine-sensitive channels by nifedipine (0.1 microM). Inhibition by spermine or spermidine did not shift the peak of the current voltage relation of the inward current. Steady-state activation and inactivation relationships were not affected and thus the amplitude, but not the voltage dependence, of the window current responsible for Ca2+ inflow during sustained depolarization was affected. Putrescine (1 mM) had no significant effect on the inward current. These results suggest that spermine and spermidine inhibit contraction in spontaneously active intestinal smooth muscle by inhibiting Ca2+ current responsible for generation of action potentials.

Transcription of spoIVB is the only role of sigma G that is essential for pro-sigma K processing during spore formation in Bacillus subtilis

Activation of pro-sigma K processing in the mother cell at late stages of sporulation in Bacillus subtilis requires the presence of active sigma G in the forespore. Placing the spoIVB gene under the control of sigma F, the early forespore transcription factor, allows sigma K to become active in the absence of sigma G. Therefore, transcription of spoIVB is the only role of sigma G that is essential for the signaling pathway between sigma G and sigma K.

Four-week oral toxicity study of 1,2-dimethyl-3-hydroxypyrid-4-one (L1) in uremic rats

A short-term oral toxicity study of 1,2-dimethyl-3-hydroxypyrid-4-one (L1), a promising oral chelating agent for the treatment of iron and aluminum overload, was carried out in uremic rats. L1 was administered to male uremic rats by gastric intubation at 0, 20, 40, 80 or 160 mg/kg/d for 4 w. Body weight and food and fluid intake were monitored daily. Complete hematologic examinations, serum biochemical parameter determinations and histological examinations were carried out. Although body weight gain was significantly reduced at 80 and 160 mg/kg/d, there were no effects of L1 on food and fluid consumption. There were no significant differences between controls and L1-treated groups in most of the hematological and biochemical parameters analyzed. No significant dose-dependent changes in relative organ weights were noted. The non-observed-adverse-effect level (NOAEL) for L1 in uremic rats was 40 mg/kg/d. According to the results of this study, uremia did not increase the toxic effects of L1.

Evaluation of predictive ability of APACHE II system and hospital outcome in Canadian intensive care unit patients

OBJECTIVES

To evaluate the ability of the acute Physiology and Chronic Health Evaluation II (APACHE II) scoring system to predict patient outcome in two Canadian intensive care units (ICUs). To compare the severity of illness and outcome of Canadian ICU patients with existing United States data.

DESIGN

Prospective data collection on 1,724 Canadian ICU patients for validation of the APACHE II system. Comparison of the outcome of Canadian ICU patients to retrospective United States data on 4,087 patients from the 1985 APACHE II multicenter study.

SETTING

Canadian data from two university teaching hospital ICUs. United States data from 13 ICUs, ten of which were in university teaching hospitals.

PATIENTS

Consecutive patients admitted to adult medical/surgical ICUs. Coronary care unit, neurosurgical and cardiac surgery patients were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

For each patient, demographic data, diagnosis, APACHE II score and hospital survival data were collected. The predicted risk of death was calculated for each patient using the APACHE II risk of death equation. The accuracy in outcome prediction of the APACHE II system was assessed by means of the receiver operating characteristic curve, 2 x 2 decision matrices and linear regression analysis. The severity of illness and hospital mortality for the Canadian patients was compared with that of United States patients from the 1985 APACHE II multicenter study. In 1,724 Canadian ICU patients, the mean +/- SEM APACHE II score was 16.5 +/- 0.2. The predicted death rate was 24.7% and the observed death rate was 24.8%. Using receiver operating curve analysis, good correlation was found between predicted outcome and observed outcome. The area under the curve was 0.86. From the 2 x 2 decision matrix constructed for a predicted risk of death of 0.5, 83% of patients were correctly classified. The sensitivity was 50.9% and the specificity was 93.6%. When observed death rate was plotted against predicted death rate, linear regression analysis gave an r2 of .99. Canadian patients had a higher death rate and APACHE II score than the United States patients. After controlling for severity of illness using the APACHE II score, the Canadian and United States death rates were similar.

CONCLUSIONS

The ability of the APACHE II system in predicting group outcome is validated in this Canadian ICU population by receiver operating characteristic curve, 2 x 2 decision matrices and linear regression analysis. The Canadian patients had a higher overall hospital death rate than the United States patients. After controlling for severity of illness using APACHE II scores, the hospital death rate was comparable between the Canadian and United States patients.

Differential actions of exogenous and intracellular spermine on contractile activity in smooth muscle of rat portal vein

Effects of the naturally occurring polyamine spermine on electrical and contractile properties of the rat portal vein were studied. 1 mM spermine nearly abolished spike activity and spontaneous contractions and decreased the intracellular Ca2+ concentration ([Ca2+]i). The phasic force responses to 0.1 and 1 microM phenylephrine were partially inhibited, but not the sustain plateau contraction caused by 5 microM phenylephrine. The Ca(2+)-force relation in high-K+ (128 mM)-depolarized veins was shifted to the right, EC50 for Ca2+ increasing from 0.50 +/- 0.03 mM (control, n = 8) to 0.65 +/- 0.06 and to 0.94 +/- 0.03 at 1 (n = 4) and 10 (n = 3) mM spermine, respectively. However, at a Ca2+ concentration of 2.5 mM, giving maximal force, there was no effect of spermine (1 mM) on either force or [Ca2+]i. Whereas extracellular spermine thus reduced contractile activity at moderate levels of stimulation, increased intracellular concentration of spermine potentiated the force response to Ca2+. Intracellular loading of spermine by reversible permeabilization increased its concentration by 2-3 times. The spontaneous activity and response to phenylephrine were unchanged. However, the Ca(2+)-force relation of depolarized veins was shifted to the left, EC50 decreasing from 0.51 +/- 0.04 mM in controls (n = 7) to 0.36 +/- 0.02 mM in the loaded veins (n = 9). Spermine increased Ca(2+)-activated force in portal veins permeabilized with beta-escin. The degree of potentiation was consistent with observed effects in spermine-loaded intact veins. The results suggest that spermine at physiological intracellular concentration may contribute to the determination of Ca2+ sensitivity in vascular smooth muscle cells.

Expression of beta 1 integrin receptors in transformed mouse epidermal keratinocytes: upregulation of alpha 5 beta 1 in spindle carcinoma cells

The adhesive properties and the expression of extracellular matrix receptors of the beta 1-integrin subfamily were analyzed in transformed epidermal keratinocyte cell lines of different stages of mouse skin carcinogenesis. One- and two-dimensional analyses of the immunoprecipitates obtained with anti-beta 1- and specific anti-alpha-integrin subunits showed qualitative and quantitative changes in the expression of beta 1 integrins by the different cell lines. The polyvalent alpha 3 beta 1 integrin was expressed by all analyzed cell lines, although the levels detected in undifferentiated spindle CarC cells were lower than those present in the rest of keratinocyte cell lines. In contrast, spindle cells expressed high levels of the specific fibronectin receptor alpha 5 beta 1, whereas this integrin was absent or expressed at very reduced levels in the other epithelial cell lines. Expression of alpha 5 beta 1 integrin in spindle cells appeared organized in cell-substratum contact areas on spread cells. In addition, high and homogenous expression of alpha 5 beta 1 was detected in fully undifferentiated tumors induced in nude mice by three independent spindle cell lines. These results suggest that the expression of alpha 5 beta 1 integrin is upregulated during the development of spindle cell carcinomas that occur in the last stages of mouse skin carcinogenesis and can be associated with the acquisition of the fibroblastoid phenotype of spindle cells. On the other hand, expression of the collagen receptor alpha 2 beta 1 was demonstrated in a transformed cell line (PDV), and it was apparently also expressed in two other malignant keratinocyte cell lines (PDVC57 and HaCa4). The expression of alpha 2 beta 1 was correlated with the increased adhesion to collagen type I and collagen type IV exhibited by the tumorigenic cell lines.

Accumulation of 3-(phenylamino)alanine, a constituent in L-tryptophan products implicated in eosinophilia-myalgia syndrome, in blood and organs of the Lewis rats

3-(Phenylamino)alanine (PAA), a newly discovered impurity in case-associated L-tryptophan tablets, has been investigated as a possible contributing factor in the etiology of eosinophilia-myalgia syndrome (EMS). We have studied distribution and elimination of PAA in rats which were administered a single 5 mg/kg dose of PAA by gastric gavage. PAA concentrations in blood, brain, kidney and liver were measured by high-performance liquid chromatography (HPLC) with electrochemical detection. The concentration of PAA in each tissue reached a maximum at 5 h, and then gradually declined. A high level of PAA still remained at 24 h, indicating gradual elimination. The concentration of PAA in brain at 5 h was 2139 ng/g tissue, demonstrating passage through the blood-brain barrier. Consecutive administration of PAA (5 mg/kg) for 4 days resulted in approximately double the concentration in all tissues. Chronic treatment using PAA incorporated into food pellets for 6 weeks resulted in similar accumulations in each tissue, and following 12 days on a PAA free diet, levels of this drug were still detectable in all tissues.

Increased muscle strength in paralyzed patients after spinal cord injury: effect of beta-2 adrenergic agonist

The administration of beta-2 adrenergic agonists in experimental animals result in an increased strength of skeletal muscle. In this study, we evaluated whether a beta-2 adrenergic agonist, metaproterenol, had an effect on muscle size and strength in a group of patients with muscular atrophy following spinal cord injury. Ten male subjects were randomly divided into 2 groups and agreed to participate in a prospective, double-blind, placebo-controlled, and crossover study. Metaproterenol (80 mg/day), or placebo, was administered orally for a period of 4 weeks. Muscle strength was measured by a force transducer interfaced with a microcomputer. Muscle size was calculated and expressed as a cross-sectional area of upper arm and forearm using a formula. Metaproterenol induced a significant increase of muscle strength in both groups of subjects, compared with placebo (p < .001). Similarly, there was an increase in a muscle size in the forearm following the administration of metaproterenol. Our data indicate that beta-2 adrenergic agonists may improve both muscle strength and size in patients with muscular atrophy following spinal cord paralysis.

Frequency of delta-F508 mutation and XV2C/KM19 haplotypes in Cuban cystic fibrosis families

We tested the frequency of the delta F508 mutation and haplotypes linked to the cystic fibrosis (CF) gene in Cuba. The delta F508 deletion was detected in 34.0% of the CF chromosomes. There was a shortage of delta F508 heterozygotes, suggesting non-randomness in mating patterns. Haplotype B (XV2C/KM19 1/2) was found on 40.5% of the CF chromosomes (71.5% of delta F508 chromosomes, 28.3% of non-delta F508 CF chromosomes) against 13.5% of non-CF chromosomes.

Transesophageal echocardiography for the diagnosis and management of nonobstructive thrombosis of mechanical mitral valve prosthesis

BACKGROUND

Diagnosis of a mechanical mitral valve prosthesis thrombosis is currently made with transthoracic Doppler echocardiography and occasionally with fluoroscopy. However, identifying a thrombus on a valve prosthesis may be difficult, especially if the thrombus is nonobstructive. To prospectively define the role of transesophageal echocardiography for identification of nonobstructive thrombi, we studied a series of patients in whom the prosthetic valve was considered to function normally on clinical examination and transthoracic echocardiography.

METHODS AND RESULTS

One hundred fourteen consecutive patients with mechanical mitral valve prosthesis were investigated by both transthoracic echocardiography and transesophageal echocardiography. These examinations were performed for recent systemic emboli (15 patients), fever of unknown etiology (11 patients), routine postoperative evaluation (56 patients), and other reasons (32 patients). Based on transthoracic echo diagnosis, all prostheses were considered normal. Yet, in 20 patients transesophageal echocardiography revealed the presence of a 2- to 15-mm-long mobile thrombus localized on the atrial surface of the prosthesis. When compared with the remaining 94 patients with no visible thrombi, there was no significant difference between the two groups in terms of incidence of atrial fibrillation (65% versus 52%), left atrial size (48 +/- 9 versus 51 +/- 13 mm), left ventricular end-diastolic diameter (49 +/- 10 versus 51 +/- 13 mm) and fractional shortening (28 +/- 9% versus 31 +/- 10%), presence of spontaneous contrast to the left atrium (40% versus 41%), transprosthetic mean pressure gradient (4.0 +/- 1.4 versus 3.9 +/- 1.5 mm Hg), or the type of prosthesis used. After we discovered a nonobstructive thrombosis, patients were treated with heparin (n = 9) or oral anticoagulation (n = 11). The presence of a localized thrombus was confirmed in 3 patients who were operated on. In the present study, evolution appeared to depend on thrombus size: of 14 patients exhibiting a small (< 5 mm) thrombus, 10 had an uneventful course, whereas 5 of 6 patients with a large (> or = 5 mm) thrombus developed complications or died.

CONCLUSIONS

Transesophageal echocardiography appears to be a reliable method to diagnose thrombi on a mechanical mitral valve prosthesis, even when transthoracic Doppler echocardiographic parameters appear to be normal. Transesophageal echo assessment of thrombus size may be helpful in deciding whether a patient with mitral prosthesis should be treated by anticoagulation, thrombolysis, or valve rereplacement.

Antibiotic resistance and penicillin tolerance in clinical isolates of group B streptococci

The aim of this study was to determine the susceptibility patterns of 100 group B streptococcal strains isolated in our hospital and to ascertain tolerance to penicillin by determining quantitative killing curves. We found two strains with intermediate susceptibility to penicillin and eight strains to ampicillin. Seventeen isolates were tolerant to penicillin, with bacterial counts decreasing 2 to 3 log during the first 8 h but still above 10(2) CFU/ml after 24 h. The kinetic study shows that penicillin tolerance is not rare among group B streptococci isolated in our hospital.

Results from a reference laboratory for prenatal diagnosis of sickle cell disorders in Cuba

A nationwide programme for the prevention of sickle cell (SS and SC) disorders was initiated in Cuba in 1983. Couples at risk were identified by screening pregnant women and the partners of those who carry an abnormal haemoglobin, followed by genetic counselling and the offer of prenatal diagnosis. Prenatal diagnosis was performed in one laboratory, which had carried out 1068 prenatal tests for Hb SS and SC disorders by the end of 1992. The centralization of the service has permitted rapid identification and resolution of problems.

Anesthetic and hemodynamic effects of single bolus versus incremental titration of hyperbaric spinal lidocaine through microcatheter

This study examined anesthetic development and hemodynamic changes during two techniques of hyperbaric lidocaine administration through 27-gauge intrathecal catheters for continuous spinal anesthesia in 55 elderly patients undergoing transurethral prostatic resection. Twenty-five patients were randomly assigned to receive hyperbaric lidocaine 5% solution in a single bolus of 75 mg to achieve blockade to approximately T6, and 30 patients to receive hyperbaric lidocaine 2.5% solution in increments of 25 mg to achieve T6 or to a maximum of three doses. Hemodynamic measurements of arterial pressure, heart rate, cardiac output, stroke volume, and ejection fraction were made serially after the induction of spinal anesthesia. Anesthesia failed to spread beyond the sacral region in 9/25 (36%) patients in the single-dose group (SD), but was successfully induced in all patients given titrated doses (TD) at total doses of 50 mg (n = 15) (TD50) and 75 mg (n = 15) (TD75). The mean maximal level of sensory block in all three groups was comparable: T5, T4, and T6 in groups SD, TD50, and TD75, respectively. The onset and progression of sensory block were rapid and similar in the SD and TD50 groups, in contrast to a gradual, stepwise development of block in group TD75. Grade 3 motor block occurred in response to the first dose of 25 mg lidocaine in 7/30 (23%) patients receiving titrated doses, but the overall incidence of leg paralysis did not differ among the three groups by the end of lidocaine dosing. Mean arterial pressure (MAP) decreased significantly relative to baseline in all three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

The estrous cycle and pituitary-ovarian function in Lewis and Fischer rats

We have characterized the estrous cycle by obtaining vaginal smears, and quantitating estradiol (E), progesterone (P), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) plasma levels at different phases of the estrous cycle in Lewis (LEW/N) and Fischer (F344/N) rats. Comparison of the duration of the component phases of estrous showed LEW/N metestrous to be significantly longer than in F344/N rats while diestrous and estrous were significantly shorter; proestrous was identical. E levels in LEW/N rats were significantly greater than in F344/N rats only in the estrous phase of the cycle. P levels were significantly greater in LEW/N rats in all phases. LH and FSH levels in the two strains did not differ. Elevated E and P levels would be expected to be associated with increased corticosterone through inhibition of the glucocorticoid negative-feedback pathway. The data reported suggest that other modulating factors in corticotropin-releasing-factor synthesis/release could be overriding both the E and P effects upon hypothalamic-pituitary-adrenal axis responsiveness.

Physiological properties of neuronal nicotinic receptors reconstituted from the vertebrate beta 2 subunit and Drosophila alpha subunits

Three cDNAs (ALS, D alpha 2 and ARD) isolated from the nervous system of Drosophila and encoding putative nicotinic acetylcholine receptor subunits were expressed in Xenopus oocytes in order to study their functional properties. Functional receptors could not be reconstituted from any of these subunits taken singly or in twos and threes. In contrast, large evoked currents (in the microA range) were consistently observed upon agonist application on oocytes co-injected with ALS or D alpha 2 in combination with the chick beta 2 structural subunit. The ALS/beta 2 and D alpha 2/beta 2 receptors are highly sensitive to acetylcholine and nicotine, and their physiological properties resemble those of native or reconstituted receptors from vertebrates. Although the physiological properties of ALS/beta 2 and D alpha 2/beta 2 receptors are quite similar, clear differences appear in their pharmacological profiles. The ALS/beta 2 receptor is highly sensitive to alpha-bungarotoxin while the D alpha 2/beta 2 receptor is totally insensitive to this agent. These results demonstrate that the Drosophila ALS and D alpha 2 cDNAs encode neuronal nicotinic subunits responding to physiological concentrations of the agonists acetylcholine and nicotine.

Enkephalinase inhibition facilitates sexual behavior in the male rat but does not produce conditioned place preference

The effects of two enkephalinase inhibitors, SCH 34826 and phospho-leu-phe, on male rat sexual behavior and conditioned place preference were evaluated. SCH 34826, administered intraperitoneally, reduced the ejaculation latency to both the first and second ejaculation at a dose of 30 mg/kg. This dose also reduced the first postejaculatory interval. No other effect was obtained with this drug. Phospho-leu-phe, administered intracerebroventricularly, increased mount and intromission latency at doses of 50 and 100 micrograms. A dose of 25 micrograms reduced the latency to the first ejaculation as well as the number of preejaculatory intromissions. The postejaculatory interval was also reduced at this dose. SCH 34826, 100 and 30 mg/kg, and phospho-leu-phe, 25 micrograms, had no effect in the conditioned place preference procedure. These observations seem to suggest that there is no functionally relevant tonic release of enkephalins. Therefore, the effects obtained on sexual behavior may indicate that enkephalins are released before and during the course of sexual activity. The function of such a release could be to facilitate ejaculatory mechanisms in the way found in the present studies. Previous work has shown that ejaculation-induced reward is opioid dependent, further supporting the hypothesis of opioid release during sexual activity. Taken together, these data suggest an important role for opioids, probably enkephalins, in the physiological control of sexual behavior.

Evaluation of the protective activity of 2,3-dimercaptopropanol and sodium 2,3-dimercaptopropane-1-sulfonate on methylmercury-induced developmental toxicity in mice

The embryotoxic and teratogenic effects of methylmercury in experimental animals have been established by several investigators. The protective activity of 2,3-dimercaptopropanol (BAL) and sodium 2,3-dimercaptopropane-1-sulfonate (DMPS, a chelator used in the treatment of inorganic and organic mercury) on methylmercury chloride (MMC)-induced maternal and developmental toxicity in mice has been evaluated in the present study. BAL and DMPS were administered subcutaneously or by gavage to pregnant mice immediately after a single oral administration of 30 mg MMC/kg given on day 10 of gestation and at 24, 48, and 72 h thereafter. Amelioration by BAL and DMPS of MMC embryo/fetotoxicity was assessed at 15, 30, and 60 mg/kg/day and at 90, 180, and 350 mg/kg/day, respectively. Treatment with BAL did not ameliorate the maternal toxicity or the developmental toxicity of MMC observed in the mouse. In contrast, DMPS at 90, 180, and 360 mg/kg/day significantly reduced the maternal lethality of MMC, whereas treatment with 180 and 360 mg DMPS/kg/day showed significant protective activity against MMC-induced embryotoxicity and teratogenicity. Based on the present findings, DMPS might be a useful chelator against the maternal and developmental toxicity induced by methylmercury.

Oral vanadate and Tiron in treatment of diabetes mellitus in rats: improvement of glucose homeostasis and negative side-effects

It has been shown that improvement of glucose homeostasis by oral vanadate or vanadyl treatment in streptozotocin-induced diabetic rats is accompanied by severe negative side effects (some deaths, decreased weight gain, alteration in renal function as well as tissue vanadium accumulation) which argue against the use of vanadium compounds in diabetes treatment. The present study was undertaken to assess the effectiveness in alleviating some signs of diabetes in streptozotocin-treated rats with oral therapy with sodium metavanadate (NaVO3) and sodium 4,5 dihydroxybenzene-1,3-disulfonate (Tiron), a chelating agent effective in mobilizing vanadium. In a preliminary experiment, diabetic rats were given aqueous solutions of 0.20 mg NaVO3/ml for 4 days. Vanadium-treated rats which showed blood glucose levels significantly lower (p < 0.001) than vanadate-untreated diabetic rats were selected for subsequent experiments. These animals were given 0.20 mg NaVO3/ml in drinking water and 0, 125.6, 314 or 628 mg Tiron/kg/d by gavage for 2 w. Although most of the animals did not become normoglycemic, several characteristic signs of diabetes (hyperglycemia, hyperphagia and polydipsia) were alleviated by the NaVO3 treatment. The administration of 314 mg Tiron/kg/d (approximately 1 NaVO3: 5 Tiron, mole ratio) did not diminish the ameliorative effects of NaVO3 with respect to diabetes, but significantly decreased the level of vanadium accumulation in target organs. These results show that some of the beneficial effects of NaVO3 are maintained in diabetic animals given Tiron, while the administration of the chelator results in a significant decrease in tissue vanadium accumulation. Accordingly, this would diminish the possibility of toxic side effects derived from prolonged oral vanadium administration.