In vitro interactions of artemisinin with atovaquone, quinine, and mefloquine against Plasmodium falciparum.

The interactions of artemisinin with atovaquone, quinine, and mefloquine were investigated in three Plasmodium falciparum strains (strains F-32, FCR-3, and K-1) by an in vitro culture assay. The parasites were cultured for 48 h in the presence of different concentrations and proportions of two drugs at a time in a checkerboard design. The response parameters were determined, and the sums of the fractional inhibitory concentrations (sigmaFICs) of the drug combinations were calculated for different degrees of inhibition (50% effective concentration [EC50], EC90, and EC99). Within therapeutically relevant molar ratios (19 to 200), the combination of quinine and artemisinin showed mean sigmaFICs of 1.71 at the EC50, 0.36 at the EC90, and 0.13 at the EC99, indicating increasing synergism. Within the range of molar ratios of 4.3 to 50, the combination of mefloquine and artemisinin yielded mean sigmaFCIs of 0.93, 0.44, and 0.31 at the EC50, EC90, and EC99, respectively, indicating synergism. The atovaquone combination showed additive activity to synergism at atovaquone/artemisinin proportions considered relevant to the in vivo situation, i.e., between 4.3 and 200, with the mean sigmaFICs decreasing from 1.34 at the EC50 to 0.85 and 0.23 at the EC90 and EC99, respectively. Interstrain differences in the degree of drug interaction were seen with the three strains for all combinations. Synergism was most consistent with quinine.

Plasmodium falciparum: in vitro interactions of artemisinin with amodiaquine, pyronaridine, and chloroquine.

In the scenario of drug-resistant Plasmodium falciparum malaria combination therapy represents an effective approach. Artemisinin and its derivatives are of special interest because they represent the most effective group of compounds against multidrug-resistant malaria with a rapid onset of action and a short half-life. Interactions of artemisinin with amodiaquine, pyronaridine, and chloroquine were therefore investigated against three strains of P. falciparum using a 48-h in vitro culture assay. Two of the strains were chloroquine sensitive and one was partially chloroquine resistant. Observed effective concentrations (O) of the combined compounds at different concentration ratios were calculated for different degrees of inhibition (EC50, EC90, EC99) and compared to expected calculated effective concentrations (E) using a probit method. Synergism with mean O/E EC90 values of 0.25 and 0.8 were found with the combination of artemisinin and the two Mannich bases, amodiaquine and pyronaridine, respectively, whereas chloroquine showed addition with a mean value of 1.2. Although both amodiaquine and chloroquine are 4-aminoquinolines, their interaction with artemisinin appears to be different. The combination of artemisinin with amodiaquine represents an important option for the treatment of falciparum malaria.

The rare association of tetralogy of Fallot with hypertrophic cardiomyopathy. Report of 2 neonatal patients.

Although tetralogy of Fallot is commonly associated with other congenital heart defects, it is rarely found in conjunction with hypertrophic cardiomyopathy. We describe the cases of 2 neonates with this rare condition, both of whom required surgical intervention during infancy. Because hypertrophic cardiomyopathy is frequently familial, and tetralogy of Fallot is commonly found in patients diagnosed with chromosomal anomalies, we speculate about a possible genetic cause for this association.

A reduction in serum glucocorticoids provokes experimental allergic encephalomyelitis: implications for treatment of inflammatory brain disease.

Glucocorticoid (GCC) therapy usually inhibits inflammatory diseases, but certain regimens can trigger relapses. Clinical use of steroids is not uniform and in some instances may be dangerous. In the present study, GCCs modified the course of experimental allergic encephalomyelitis (EAE) in Lewis rats, a model of inflammatory CNS disease. Continuous treatment with dexamethasone (DEX) completely blocked EAE. RU 486, a GCC antagonist, counteracted the effects of endogenous GCCs and worsened EAE. Sudden withdrawal of DEX also caused severe clinical and histologic exacerbations at a time when paired saline-treated animals had completely recovered. In rats that had complete clinical recovery from EAE, and would not have relapsed without this acute steroid deficit, a short pulse of DEX was followed by severe exacerbations. In contrast, a slow steroid taper prevented exacerbations. Abrupt discontinuation of GCCs provokes inflammatory brain disease.

Prostaglandins and inhibitors of arachidonate metabolism suppress experimental allergic encephalomyelitis.

Experimental allergic encephalomyelitis (EAE) is an autoimmune inflammatory disease of the central nervous system (CNS). It is an animal model of post-infectious encephalomyelitis and multiple sclerosis (MS). Acute EAE is mediated by macrophages and by T helper 1 (Th1) lymphocytes directed against brain antigens. Inflammation in EAE could potentially be modified by prostaglandins (PG) secreted by blood monocytes (Mo) and brain glial cells. PGE elevates cAMP, which inhibits Mo function and selectively blocks secretion of cytokines by Th1 cells. In the present study, we found that a long-acting PGE1 analogue (LAPGE) inhibited clinical and histological EAE. Indomethacin (INDO) also suppressed active EAE. The combination of INDO plus LAPGE inhibited disease further, possibly by allowing LAPGE to function unopposed by immunostimulatory PG. EAE was suppressed when these agents were administered from the time of immunization or from the onset of clinical disease. The combination of INDO plus LAPGE also inhibited delayed-type hypersensitivity (DTH) reactions to myelin basic protein (MBP), and diminished in vitro lymphocyte responses to mitogens and MBP. PGE analogues and modifiers of arachidonate metabolism block autoimmune responses to brain antigens in vitro and in vivo, and may ameliorate inflammatory and autoimmune diseases of the brain and other organs.

Cardiac diastolic function in pediatric patients receiving doxorubicin.

The purpose of the study was to compare systolic and diastolic function in pediatric patients treated with doxorubicin. Left ventricular function was evaluated in 61 children prior to and following chemotherapy. None had clinical evidence of cardiac decompensation prior to treatment. All received relatively low cumulative doses of doxorubicin; the majority received the drug by continuous infusion. Systolic function was estimated using fractional shortening; diastolic function was estimated using A wave velocity, E wave velocity, E to A ratio, and deceleration time. There was a small but significant decline in systolic cardiac function as estimated from changes in fractional shortening that could not be appreciated in any of the measured parameters of diastolic function. A variety of reasons that could be responsible for the absence of significant changes in diastolic function are discussed. For the present, estimations of systolic function are preferred over the studied parameters of diastolic function in the evaluation of cardiac status in pediatric patients receiving doxorubicin containing regimens.

Balloon pulmonary valvuloplasty in the management of cyanotic congenital heart defects.

Twenty-three children with cyanotic congenital heart defects, aged 3 days to 11.5 years, weighing 2.9 to 30 kg, underwent percutaneous balloon pulmonary valvuloplasty to improve pulmonary oligemia. The patients were divided into two groups: group I with intact ventricular septum and group II with ventricular septal defect. In 12 group I patients, there was an increase of systemic arterial oxygen saturation [83 +/- 8% (mean +/- SD) vs. 94 +/- 5%, P less than 0.001] and pulmonary-to-systemic flow ratio (0.7 +/- 0.1 vs. 1.0 +/- 0.2, P less than 0.001). Peak systolic pressure gradient across the pulmonary valve decreased (P less than 0.001) from 105 +/- 48 to 25 +/- 18 mm Hg. In 11 group II patients, arterial oxygen saturation (67 +/- 13 vs. 83 +/- 13%, P less than 0.01) and pulmonary-to-systemic flow ratio (0.7 +/- 0.4 vs. 1.2 +/- 0.5, P less than 0.02) increased following valvuloplasty. Peak systolic pressure gradient across the pulmonic valve (52 +/- 16 vs. 32 +/- 22 mm Hg, P less than 0.05) decreased while infundibular and total pulmonary outflow tract gradients were unchanged (P greater than 0.1). Immediate surgical intervention was avoided in all cases in both groups. On follow-up, 1 to 36 months after valvuloplasty, arterial oxygen saturation, pulmonary-to-systemic flow ratio, and pulmonary valve gradients remain improved in both groups. However, in group I, repeat balloon valvuloplasty was required in two children. In group II, six children with tetralogy of Fallot (TOF) underwent successful total surgical correction 4 months to 2 years after valvuloplasty.(ABSTRACT TRUNCATED AT 250 WORDS)

Intrapulmonary agenesis of venous system and bronchopulmonary arterial anastomosis.

Agenesis of the intrapulmonary and extrapulmonary veins of the right lung was found by angiography and histological examination in a three year old boy. Blood supplied by the intersegmental arteries drained via the pulmonary arteries of the right lung into main and left pulmonary arteries. This caused a shunt between the aorta and pulmonary artery. Agenesis of the pulmonary venous system as a cause of left to right shunt has not been reported before.

Secretory immune responses in the mouse vagina after parenteral or intravaginal immunization with an immunostimulating complex (ISCOM).

Immunostimulating complexes (ISCOMs) are subunit vaccines that are particularly effective in producing immunity against systemic viral infections, but their effectiveness against mucosal infections has received little attention. To study their ability to produce mucosal immune responses in the female reproductive tract, a model ISCOM was prepared containing sheep erythrocyte membrane proteins, and anti-erythrocyte IgA and IgG titres in mouse vaginal washings were measured after immunization at parenteral or local mucosal sites. The ISCOM was prepared by a modified procedure that resulted in incorporation of 10-15% of initial membrane protein compared with 1-5% previously reported. Electrophoretic analysis demonstrated that four out of five erythrocyte membrane proteins were incorporated into the ISCOM, and electron microscopic observations indicated that the ISCOM had a cage-like structure with a diameter of 40 nm, similar to previous ISCOMs. Immunization in the pelvic presacral space (p.s.-p.s.) stimulated significantly higher anti-erythrocyte IgA titres in vaginal fluid than were produced by intraperitoneal (i.p.-i.p.), subcutaneous (s.c.-s.c.), intravaginal (i.vag.-i.vag.), or i.p.-i.vag. immunizations with the same vaccine. Specific IgG titres were less dependent on the route of immunization, with p.s.-p.s., i.p.-i.p. and s.c.-s.c. administration all giving similar high titres while i.p.-i.vag. treatment induced lower titres. These observations using a model ISCOM indicate that mucosal immune responses against membrane proteins were elicited in the female reproductive tract, and that non-mucosal immunization in the pelvis was a more effective route of administration than local application of the ISCOM to the vaginal mucosa.

Follow-up results of balloon angioplasty of native coarctation in neonates and infants.

The purpose of this study is to present intermediate-term results of balloon angioplasty of native aortic coarctation in neonates and infants less than 1 year of age. During a 60-month-period that ended in January 1990, 19 infants ages 3 days to 12 months (median, 2.5 months), underwent balloon angioplasty of native coarctation with resultant reduction in peak-to-peak systolic pressure gradient from 39 +/- 12 mm Hg (mean +/- SD) to 11 +/- 7 mm Hg (p less than 0.001) and increase in coarctation segment size from 2.2 +/- 0.8 mm to 4.7 +/- 1.0 mm. None required immediate surgical intervention. Thirteen of the 19 (68%) had severe associated cardiac defects. There was one death (5%) 2 days after balloon angioplasty, and it was related to associated cardiac defect. One infant was lost to follow-up. It is too soon to restudy one infant. The remaining 16 infants had clinical (36 +/- 18 months) and catheterization (12 +/- 4 months) follow-up data. The residual coarctation gradient (22 +/- 15 mm Hg) and coarcted segment size (4.4 +/- 1.6 mm) remain improved (p less than 0.01) when compared with pre-balloon angioplasty values. Five of the 16 (31%) infants (four were neonates at the time of balloon angioplasty) had evidence for recoarctation (defined as gradient greater than 20 mm Hg) and underwent surgical resection (two) or repeat balloon angioplasty (three), all with success. None developed aneurysms.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of adjuvants on antibody titers in mouse vaginal fluid after intravaginal immunization.

Intravaginal (ivag) immunization elicits secretory immune responses in the female reproductive tract, but little is known about the safety and effectiveness of adjuvants for such immunization. Mice were immunized intravaginally once daily for 5 days with large doses of horse ferritin combined with aluminum hydroxide (AH), muramyl dipeptide (MDP), monophosphoryl lipid A (MPL), dimethyl dioctadecyl ammonium bromide (DDA) or cholera toxin (CT). Titers of anti-ferritin IgA and IgG were measured in vaginal fluid by ELISA. The most effective adjuvant for ivag primary immunization was AH, while MPL was most effective for ivag boosting. None of the adjuvants caused a detectable tissue reaction in vaginal mucosa. Primary ivag immunization for 5 days with ferritin and AH followed by ivag boosting for 5 days with ferritin and MPL elicited higher IgA titers in vaginal fluid than systemic priming and boosting with ferritin and AH or systemic priming and ivag boosting with ferritin and MPL. Systemically immunized animals exhibited the highest IgG titers in vaginal fluid. The data indicate that adjuvants, particularly AH, can increase local immune responses to intravaginal immunization, but it should be noted that multiple applications of large doses of antigen were used and that this route of sensitization may be relatively inefficient.

Secretory immune responses in mouse vaginal fluid after pelvic, parenteral or vaginal immunization.

Intravaginal immunization causes IgA responses in vaginal fluid, but so far lymphoid nodules in mouse vaginal mucosa have not been detected. The present study was therefore designed to test the hypothesis that IgA responses in the female reproductive tract may be generated in the regional iliac lymph nodes. Two, non-mucosal sites were identified in the female mouse pelvis, the subserous and presacral spaces, from which lymph drains mainly to the iliac nodes. Immunization at these pelvic sites with horse ferritin adsorbed to aluminum hydroxide (AH) caused much higher IgA and IgG titres in vaginal fluid than intravaginal immunization; moreover, the pelvic immunizations caused significantly higher and better sustained IgA titres in vaginal fluid than subcutaneous immunization near the scapulae or in the perineum, while IgG titres in vaginal fluid were similar in these groups. Additional mice were immunized with ferritin subcutaneously near the scapulae or in the presacral pelvic space using dimethyl dioctadecyl ammonium bromide (DDA), AH plus muramyl dipeptide, or the Ribi adjuvant system as adjuvants. Pelvic immunization caused higher IgA titres in vaginal fluid than subcutaneous immunization in each case. The IgA response stimulated by DDA was similar to that produced by AH but higher than the responses caused by the other two adjuvants, while IgG titres were similar with all four adjuvants in both sites. The results suggest that non-mucosal, pelvic immunization is particularly effective in stimulating IgA responses in the female reproductive tract. The observation is consistent with the possibility that the iliac lymph nodes may play a role in the development of IgA responses in the reproductive tract.

Use of propranolol for severe dynamic infundibular obstruction prior to balloon pulmonary valvuloplasty (a brief communication).

A case of severe pulmonary valvar stenosis and infundibular obstruction has been reported. Infundibular obstruction was so severe that no catheter could be advanced into the pulmonary artery. Propranolol, 0.5 mg given intravenously, reduced the obstruction and allowed the balloon dilatation of the pulmonary valve to be carried out without complication. Subsequently oral propranolol helped to remove the infundibular obstruction. We strongly recommend the use of propranolol when infundibular obstruction is present prior or after the balloon pulmonary valvuloplasty.

Intermediate-term follow-up results of balloon aortic valvuloplasty in infants and children with special reference to causes of restenosis.

Sixteen infants and children with valvular aortic stenosis underwent percutaneous balloon aortic valvuloplasty over a 36-month period ending August 1988. The mean systolic pressure gradient across the aortic valve decreased from 72 +/- 21 (mean +/- standard deviation) to 28 +/- 13 mm Hg (p less than 0.001) immediately after valvuloplasty; the degree of aortic insufficiency did not significantly increase. Follow-up catheterization (in 10 patients) and Doppler data (in all 16 patients) were available 3 to 32 months (mean 12 months) after valvuloplasty and revealed a residual aortic valvular gradient of 37 +/- 23 mm Hg, which continues to be significantly lower (p less than 0.001) than that before valvuloplasty. There was no increase in aortic insufficiency. On the basis of follow-up data, the 16 children were divided into 2 groups: group I with good results (gradients less than or equal to 49 mm Hg), 12 patients; and group II with poor results (gradients greater than or equal to 50 mm Hg), 4 patients. All 4 patients in group II required repeat balloon valvuloplasty or surgical valvotomy; none from group I required these procedures. Seventeen general, anatomic, physiologic and technical variables were examined by a multivariate logistic regression analysis to identify factors associated with restenosis; these risk factors were: age less than or equal to 3 years; and immediate aortic valvular gradient after valvuloplasty greater than or equal to 30 mm Hg. The immediate and intermediate-term follow-up results of balloon aortic valvuloplasty are encouraging. Recognition of the risk factors may help identify potential candidates for recurrence.(ABSTRACT TRUNCATED AT 250 WORDS)

Significance of infundibular obstruction following balloon valvuloplasty for valvar pulmonic stenosis.

This study was designed to define the prevalence and significance of infundibular obstruction following balloon pulmonary valvuloplasty. Thirteen of 62 children had infundibular gradients prior to valvuloplasty; five of these disappeared following balloon valvuloplasty. Five other children without pre-valvuloplasty infundibular gradients but with angiographic infundibular narrowing developed new infundibular gradients following valvuloplasty. Propranolol was administered to six children because of severe infundibular constriction, with improvement. None required surgical intervention. At follow-up the infundibular gradients either diminished or disappeared. The infundibular gradients appear to be more frequent with increasing age and severity of pulmonary valvar obstruction. Children developing systemic or suprasystemic right ventricular pressures after balloon pulmonary valvuloplasty may be candidates for propranolol therapy. Regression of the infundibular stenosis at follow-up can be expected, as has been observed after surgical pulmonary valvotomy. Because the infundibular obstruction can be successfully managed, balloon pulmonary valvuloplasty remains the treatment of choice for isolated valvar pulmonary stenosis. Use of balloon valvuloplasty in children less than 5 years of age and/or prior to development of pulmonary gradients in excess of 80 mm Hg may reduce the chance for development of infundibular reaction.

Causes of recoarctation after balloon angioplasty of unoperated aortic coarctation.

During the 35 month period ending December 1987, 30 children, aged 14 days to 13 years, underwent balloon angioplasty of unoperated aortic coarctation with resultant reduction in coarctation gradient from 43.6 +/- 20.4 to 9.5 +/- 7.6 mm Hg (p less than 0.001). None of the patients required immediate surgical intervention. On the basis of results of 6 to 30 month follow-up catheterization data in 20 children, the patients were classified as follows: Group A, 13 patients with good results (gradient less than or equal to 20 mm Hg and no recoarctation on angiograms) and Group B, 7 patients with fair or poor results (gradient greater than 21 mm Hg with or without recoarctation on angiography). No patient developed aortic aneurysm at the site of angioplasty. Thirty variables were examined by multivariate logistic regression analysis and four factors were identified as risk factors for development of recoarctation: 1) age less than 12 months, 2) aortic isthmus less than 2/3 the size of the ascending aorta immediately proximal to the right innominate artery, 3) coarcted aortic segment less than 3.5 mm before dilation, and 4) coarcted aortic segment less than 6 mm after angioplasty. The identification of risk factors may help in selection of patients for balloon angioplasty. Avoiding or minimizing the number of risk factors may help reduce the chance of recoarctation after angioplasty. The intermediate-term follow-up results with regard to recoarctation are comparable with those after surgical repair of coarctation. Recoarctation after angioplasty was dealt with by repeat balloon angioplasty or surgical resection for those requiring treatment and clinical follow-up for the remaining children.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of specific antibody responses in mouse vaginal fluid after immunization by several routes.

Mice were immunized with a protein antigen, horse ferritin, by eight different routes and the immune responses in the reproductive tract were compared by measuring specific IgA and IgG in vaginal fluid and by localizing anti-ferritin plasma cells in uterine horns, cervix and vagina. The eight routes of immunization were: subcutaneous with Freund's adjuvant (s.c.), intragastric (i.g.), intravaginal (i.v.), s.c.-i.g., s.c.-i.v., i.g.-i.v., i.v.-i.v. and s.c.-i.g.-i.v. The largest overall response, considering both IgA and IgG antibodies, was obtained by s.c. priming with ferritin in adjuvant followed by i.v. boosting. Intravaginal immunization also boosted priming by the i.g., s.c.-i.g. and i.v. routes, but the response to i.v. immunization alone was weak. All i.v. immunizations stimulated mainly IgA antibody responses in vaginal fluid. Specific plasma cells, mostly of the IgG isotype, were present in the vaginal fornix of several mice in the s.c.-i.v. and s.c.-i.g.-i.v. groups, but none were detected there in any other group and they were only rarely observed in the uterine horns. The results provide data on the relative effectiveness of different routes of immunization in producing a humoral immune response in vaginal fluid against a non-replicating antigen.

Hormonal control of implantation in guinea pigs.

In the guinea pig, for which implantation is supposedly progesterone-dependent, actual hormonal requirements were assessed by measuring the levels of circulating estradiol and progesterone and correlating them with their content in the ovaries and uterus, and uterine concentrations of their receptors prior to, during, and immediately after implantation. Ovarian and uterine content and plasma levels of estradiol and progesterone, as well as uterine cytosolic receptors of these two hormones, were high at proestrus. Up to day 3 of pregnancy, estradiol remained high in peripheral plasma, ovarian and uterine tissues, but reached low levels at the time of implantation. The levels of progesterone showed a gradual increase in plasma and ovaries till the time of implantation, with the embryonic site of the uterus accumulating more of progesterone compared to estradiol. As pregnancy progressed, a gradual translocation of cytosolic to nuclear receptors occurred, both with estradiol and progesterone receptors. Comparing the receptor values for estradiol at each uterine site showed no significant alterations between embryonic and interembryonic cytosolic receptors. While significantly high levels of nuclear estradiol receptor were found at the inter-embryonic site on day 9 of pregnancy, the cytosolic and nuclear progesterone receptor concentrations were greater at the embryonic site on the same day. These findings demonstrated that the uterus is adequately exposed to estradiol and progesterone prior to ovulation and again in early pregnancy (day 1-3), thus facilitating implantation in the guinea pig (on days 7-8).

Balloon angioplasty for coarctation of the aorta: immediate and long-term results.

Twenty-five infants and children with native coarctation of the aorta had percutaneous balloon angioplasty over a 28-month period ending in May, 1987. The mean systolic pressure gradient across the coarctation decreased from 47.6 +/- 20.9 mm Hg to 10.3 +/- 7.3 mm Hg (p less than 0.001) following angioplasty, and the diameter of the coarcted segment increased from 3.2 +/- 1.7 mm to 7.8 +/- 3.5 mm (p less than 0.001). Clinical and echo-Doppler follow-up indicated excellent results in 16 of the 18 patients in whom 3- to 22-month follow-up was available; two infants required additional treatment (repeat angioplasty in one and surgical resection in the other). Fourteen patients who underwent repeat cardiac catheterization remain improved with regard to pressure gradient across the dilated coarctation (9.5 +/- 9.6 mm Hg, p less than 0.001) and angiographically measured sizes of the coarcted segment (10.3 +/- 3.2 mm, p less than 0.001). No aneurysm was seen in any child. We recommend balloon angioplasty as the therapeutic procedure of choice for relief of severe, previously unoperated coarctation of the aorta in neonates and young infants. Routine use of balloon angioplasty for unoperated coarctation of the aorta in children appears indicated, but should await longer follow-up results and reports of follow-up on a larger number of patients; this caution is mainly based on reports from other workers of aneurysm formation at the site of balloon dilatation.