Investigation of magnesium absorption in children using<Superscript>28</Superscript>Mg

Membrane-bound acid -glucosidase of human spleen was solubilized with either sodium cholate or Cutscum. The solubilized enzyme in type 1 (adult) Gaucher disease was less heat-stable than the normal enzyme, and when precipitated by ammonium sulphate it had a higher apparent molecular weight than the corresponding normal enzyme. The normal -glucosidase was activated by taurocholate, whereas the Gaucher enzyme was inhibited. The decrease in acid -glucosidase activity in Gaucher disease was associated with a profound deficiency of that form of the enzyme which bound to Concanavalin A. The results are consistent with faulty processing of newly synthesized acid -glucosidase in type 1 Gaucher disease.     

Intratumoral injection of interferon-gamma gene-modified dendritic cells elicits potent antitumor effects: effective induction of tumor-specific CD8<Superscript>+</Superscript> CTL response

Purpose To examine the antitumor efficacy of intratumoral injection of interferon-gamma gene-modified dendritic cells (DC-IFN-) in a B16 melanoma model and to investigate its related immunological mechanisms.Methods C57BL/6 mice-derived DC were transfected with adenovirus encoding IFN- or -galactosidase (DC-LacZ). Secretion of IFN- and TNF- by DC was detected by ELISA. Nitric oxide (NO) production was measured by Griess reaction. Cytotoxicity of DC against tumor cell lines and activity of cytotoxic T lymphocytes (CTLs) were determined by ⁵¹Cr-release assay. TRP-2aa180–188-specific CD8⁺ CTLs in tumor-bearing mice with different treatment were determined by ELISPOT.Results DC-IFN- could secrete high levels of IFN-, NO and TNF-. DC-IFN- were cytolytic to B16 melanoma cells in vitro, but DC-LacZ and DC were not. Significant inhibition of tumor growth and prolonged survival were achieved in tumor-bearing mice intratumorally injected with DC-IFN- when compared with those in tumor-bearing mice intratumorally injected with DC, DC-LacZ, fibroblasts, IFN- gene-modified fibroblasts or PBS. After treatment with DC-IFN-, enhanced Th1 and decreased Th2 responses were observed, and B16 melanoma antigen TRP-2aa180–188-specific CD8⁺ CTLs were induced significantly in the tumor-bearing mice.Conclusions Intratumorally injected DC-IFN- can uptake tumor antigens in situ and cross-present tumor antigens to specific CD8⁺ T cells, hereby eliciting effective antitumor effects in murine model with preestablished B16 melanoma.     

Association of<Emphasis Type="Italic"> TAP2</Emphasis> gene polymorphisms in Chinese patients with rheumatoid arthritis

The aim of this study was to investigate the association between the polymorphism of transporters associated with antigen processing (TAP1/TAP2) genes and rheumatoid arthritis in Chinese patients. A total of 100 RA patients and 99 healthy control subjects were enrolled. Analyses with polymerase chain reaction (PCR) based restrictions were used to identify the polymorphisms of the TAP1 and TAP2 genes, which were mapped on chromosome 6. There was a significant difference in the distribution of the TAP2 gene codon 565 polymorphism frequency between the RA patients and healthy control subjects (p<0.001). The odds ratio for the risk of the A allele in RA patients was 1.60 (95% CI: 0.82–2.92). No statistical associations in the distribution of the TAP1 gene polymorphism frequency were found between RA patients and controls. There were some physical links found between TAP1/TAP2 gene polymorphism loci. However, there was no linkage observed from TAP1/TAP2 gene polymorphisms and HLA-DRB1*04 between RA patients and healthy controls. We concluded that the TAP2 gene codon 565 A allele was associated with RA in Chinese patients in Taiwan. Individuals possessing the A allele had a higher incidence of RA. A lack of association of TAP1 gene polymorphisms between RA patients and healthy individuals was noted. The results of this study provide genetic evidence that TAP2 gene codon 565 polymorphism may play a role in RA.Abbreviations MHC Major histocompatibility - MS Multiple sclerosis - PCR Polymerase chain reaction - RA Rheumatoid arthritis - SNP Single nucleotide polymorphism     

Rapid detection of −α 4.2 deletion of α-thalassemia-2 by polymerase chain reaction

Summary We sequenced part of the X boxes of-thalassemia-1 of Southeast Asia type (- -SEA) with– ^4.2,– ^3.7,– ^G-Taichung, and ^CS. We found the X box of– ^3.7 belonged to the X box of 2 globin gene and the X box of ^cs contained X boxes of both al and2 globin gene, whereas the X box of– ^4.2 and– ^G-Taichung was a hybrid of X boxes of 2 and 1 globin gene. We also found there are two types of– ^4.2 deletion; type 1 is a common type of– ^4.2 deletion and type 2 is linkage to– ^G-Taichung. We used a combination of two methods, the amplification refractory mutation system (ARMS) and the amplified created restriction sites (ACRS), to amplify the hybrids of X boxes specifically. The upstream primer for X box of2 globin gene was designed following the standard ARMS procedure to amplify the X segment of the-globin gene. The downstream primer was designed according to the ACRS method to check the specificity of PCR products. Using this approach, we can diagnose the different types of– ^4.2 deletion. This kind of approach can also be used to amplify the specific region from the cluster of highly homologous genes.     

Detection of coronary arterial microvascular disorders using <Superscript>99m</Superscript>Tc-tetrofosmin uptake increase during exercise and coronary blood flow velocity patterns obtained by magnetic resonance imaging

This study reports an evaluation of coronary arterial blood flow patterns in patients with diabetes mellitus and healthy subjects using magnetic resonance coronary angiography (MRCA). Twenty patients with diabetes mellitus (DM group) and 20 healthy subjects (N group) were studied using MRCA and myocardial SPECT images using ^99mTc-tetrofosmin (TF). The rate of change in myocardial TF uptake was measured during a 1-day protocol of exercise and rest. Initial and delayed exercise single photon emission computed tomography (SPECT) images were acquired 30min and 3h after injection (370MBq of TF) (TF1 and TF2, respectively). Thereafter, 740MBq of TF was administered intravenously, again, and resting SPECT images (TF3) were acquired 30min later. The myocardial counts of these three points of acquisition were defined, and the rate of change of myocardial TF uptake between exercise and rest was determined. The % increase in uptake was significantly lower in the DM group than in the N group in all myocardial segments. The average coronary arterial diastolic velocity determined using MRCA was slightly lower in the DM group than in the N group, and the average systolic peak velocity (ASPV) was slightly greater in the DM group than in the N group, although these values were not statistically significant. The diastolic/systolic velocity ratio (DSVR) in the DM group was significantly lower than that in the N group (P 0.05). There was a significant correlation between DSVR and % uptake increase (r = 0.605, P 0.05). These results indicate that the measurements made using MRCA and the % uptake increase measured using TF myocardial scintigraphy represent a potentially useful noninvasive method for diagnosing microvascular dysfunction in diabetic patients.     

Comparison between the <Superscript>13</Superscript>C-urea breath test and stool antigen test for the diagnosis of childhood <Emphasis Type="Italic">Helicobacter pylori</Emphasis> infection

Background As noninvasive tests for Helicobacter pylori infection, the ¹³C-urea breath test (UBT) and stool antigen test have been widely used. In children, however, there are few studies reporting which test shows superior performance. The purpose of this study was to compare the ¹³C-UBT and stool antigen test for their accuracy in diagnosing H. pylori infection in children.Methods A total of 123 Japanese children, ages 2 to 17 years (mean, 12 years) who underwent gastric biopsies for H. pylori infection were studied. The diagnoses included gastritis (n = 55), gastric ulcer (n = 5), duodenal ulcer (n = 20), iron-deficiency anemia (n = 7), and other conditions (n = 36). The cutoff value of the ¹³C-UBT was defined to be 3.5. The stool antigen test was performed using the HpSA enzyme-linked immunosorbent assay (ELISA) (Premier Platinum HpSA). In 16 patients who received eradication therapy, the ¹³C-UBT and HpSA were repeated 2 months after treatment.Results Based on biopsy tests, 60 children were infected with H. pylori and 63 children were not. For the ¹³C-UBT, the sensitivity, specificity, and accuracy were 95.0% (95% confidence interval [CI], 86.1%–99.0%), 98.4% (95% CI, 91.5%–100%), and 96.4% (95% CI, 93.6%–99.9%), respectively. For the HpSA, the sensitivity, specificity, and accuracy were 98.3% (95% CI, 90.8%–100%), 98.4% (95% CI, 91.2%–100%), and 98.3% (95% CI, 96.0%–100%), respectively. There were no significant differences between the performance of these two tests. In the assessment of H. pylori eradication, the results of ¹³C-UBT and HpSA agreed with those of biopsy tests.Conclusions The ¹³C-UBT and the HpSA are equally accurate for the diagnosis of active H. pylori infection in Japanese children.Kazuie Iinuma, for the Japanese Pediatric Helicobacter study Group     

Distribution pattern of α and β myosin in normal and diseased human ventricular myocardium

Summary All fibers in three normal, four dilated, and two ischemic human ventricles were classified according to their myosin content using three sets of monoclonal antibodies each specific for one myosin heavy chain isoform (, and ). Numerous fibers contained only myosin heavy chain (denoted as fibers), others contained either and , or and myosin heavy chain (denoted as and fibers, respectively). The percentages of fibers were systematically determined along the walls of seven homologous regions of the ventricular myocardium.In all ventricles, there was an -fiber transmural gradient, with less fiber in the subendocardium than in the subepicardium. More fibers were found in the right than in the left ventricular wall but there was no difference between the mid-portion and the apex of the free wall of each ventricle. The diseased ventricles contained a lower fiber percentage than the normal hearts. fibers were very rare in the normal ventricles (less than 5%) and almost inexistent in pathological hearts. The correlation between the mean fiber percentages of the diseased hearts and their cardiac indices (r=0.88, P<0.05) suggests that the small amount of myosin distributed in a large number of ventricular fibers could play a role in the contractile performance of the heart. In conclusion, this study provides evidence for 1) an fiber transmural gradient, and 2) a lower myosin ratio in discased than in normal human ventricle.This work was supported in part by L'Institut National de la Santé et de la Recherche Médicale 101 rue de Tolbiac, 75013 Paris     

Inhibition ofO 6-alkylguanine-DNA alkyltransferase and DNase I activities in vitro by some alkylating substances and antineoplastic agents

Summary The specificities of the DNA repair enzymeO ⁶-alkylguanine-DNA alkyltransferase from brain and liver cells of the chick embryo and of DNase I were demonstrated in vitro by their response to substrate DNA pretreated with monofunctional alkylating agents of differentO ⁶-guanine alkylating ability and some antineoplastic agents. Treatment of DNA with ethidium bromide, Hoechst 33258, doxorubicin, Fe²⁺/bleomycin, and suramin resulted in a dose-dependent diminution of alkyltransferase activity (DE₅₀ 5 g/ml, 15 g/ml, 5 g/ml, 5 g/ml, 100 g/ml, respectively). Apart from bleomycin, comparable results were obtained with DNase I. Thermal denaturation of the substrate DNA reduced both alkyltransferase and DNase I activity. No effect was seen with X-irradiation. Cisplatin decreased only DNase I activity. Some topoisomerase II and/or gyrase inhibitors remained without significant effects on the alkyltransferase reaction whereas DNA catabolism by DNase I was diminished in a dose-dependent manner (DE₅₀ between 6.5 and 19 g/ml).Abbreviations AT alkyltransferase - BB bisbenzimide - EB ethidium bromide - DOX doxorubicin - CDDP cis-diamminedichloroplatinum (II) - MMS methylmethanesulphonate - EMS ethylmethanesulphonate - MNU methylnitrosourea - ENU ethylnitrosourea     

Construction of an EGF receptor-mediated histone H1<Superscript>0</Superscript>-based gene delivery system

Purpose To construct an EGF receptor (EGF-R)-mediated histone H1⁰-based gene delivery system for gene therapy.Methods A recombinant DNA containing histone H1⁰, EGF-R ligand, and endosomalytic domains was constructed in a prokaryotic vector and expressed in E. coli. Expression of the -galactosidase (-gal) gene in the tumor cells and tissues was observed after transduction of the -gal gene packaged by purified fusion proteins in vitro and in vivo.Results As an extension of the research on previously reported chemically synthetic composite polypeptide gene delivery systems, this genetically engineered polypeptide has proved to be capable of targeting the -galactosidase (-gal) gene into EGF-R-positive cancer cells both in vitro and in vivo. We also studied the time course of -gal gene expression in tumor tissues delivered in vivo by this polypeptide vector. At 24 h after administration, expression of the -galactosidase gene in tumor reached peak levels. The dosage optimization of administered polyplex was also investigated. The optimal dose of polyplex per mouse was 1 g DNA packaged by 3 g of composite polypeptide.Conclusions The genetically engineered polypeptide based on histone H1⁰ is a promising gene delivery system targeting EGF-R.This work was supported by a grant from the Biotechnology Key Project, National High Technology Program of China (Project No. Z20-01-01). Patent involved: CN/02136162.2, WO98/18951 (PCT/CN97/00106)     

The <Emphasis Type="Italic">Matalisi</Emphasis>: Pathway to Early Sexual Initiation Among the Youth of Mpigi,Uganda

This paper describes the role and personal characteristics of the matalisi, a previously unreported phenomenon uncovered during a study of youth sexual behavior in Uganda. The matalisi, a go-between, played a central role in sexual relationships of most youth in Mpigi, Uganda. The first phase of the study was an ethnographic inquiry of youth (ages 10–16) sexual behavior. During this phase it became evident that matalisis were used in most courtships and initial sexual liaisons. The second phase included a sociometric investigation of youth networks and a mini survey of youth who had been matalisis. Among youth interviewed, 47.3% of males (105/222) and 14.1% of females (42/298) had experienced sexual intercourse. For 88%, participating as someones matalisi preceded first coitus. By understanding the role of the matalisi, interventions may be developed to improve sex education and more effectively address sexual behaviors that lead to unwanted pregnancies, STIs, and HIV infection.     

<Superscript>18</Superscript>F-FDG PET in the detection of extrahepatic metastases from hepatocellular carcinoma

Background Positron emission tomography (PET) with ¹⁸F-fluoro-2-deoxy-d-glucose (¹⁸F-FDG) is useful in detecting distant metastases from a variety of malignancies. However, its efficiency in detecting distant metastases from hepatocellular carcinoma (HCC) has not been investigated. The aim of this study was to evaluate the usefulness of ¹⁸F-FDG PET for the detection of extrahepatic metastases from HCC.Methods Nineteen patients suspected of having extrahepatic HCC underwent ¹⁸F-FDG PET. Fourteen patients (group A) had extrahepatic lesions, which were detected by conventional studies. In five patients (group B), conventional imaging showed no extra- or intrahepatic lesions, but the tumor marker levels were elevated. The PET results were compared with those obtained by histopathology or by clinical follow-up.Results The detection rate of ¹⁸F-FDG PET was 83% (24 of 29 metastases) for extrahepatic metastases larger than 1cm in greatest diameter and 13% (1 of 8 metastases) for lesions less than or equal to 1cm. PET revealed two bone metastases not depicted by bone scan, and detected the nodal metastasis and intestinal metastases inconclusive on computed tomography. Extrahepatic lesions were resected in 5 patients of group A on the basis of PET findings. In all patients of group B, PET results were true negative for extrahepatic metastases, but HCCs were detected in the liver within 4 months in 4 patients. These were no false-positive lesions in either group.Conclusions This preliminary study suggested that ¹⁸F-FDG PET could provide additional information and contribute to the management of HCC patients suspected of having extrahepatic metastases.     

Block of HERG current expressed in HEK293 cells by the Na<Superscript>+</Superscript>-channel blocker cibenzoline

A Na⁺-channel blocker, cibenzoline, blocks the delayed rectifier potassium current (I_k), but its detailed action on the rapidly activating component (I_kr) of I_k encoded by the human ether-a-go-go-related gene (HERG) has not been clarified. We examined the effects of cibenzoline on stably expressed HERG current in HEK293 cells recorded by the patch-clamp technique of whole-cell configuration. Cibenzoline blocked HERG current expressed in HEK293 cells with IC₅₀ = 3.7 ± 0.963µM and Hill coefficient = 0.74 ± 0.12. Voltage-depended activation was shifted in a negative direction by cibenzoline. No block or minor block was induced at test depolarization of –40 to –30mV, and the block increased with depolarization reaching a plateau at 0mV without a further increase at positive voltages. Voltage-dependent activation of HERG currents became faster at negative test voltages but there were no changes at positive voltages after cibenzoline. No frequency-dependent block of HERG tail current by cibenzoline after equilibration was noted between 1.33 and 0.2Hz. Steady-state inactivation of the HERG current was shifted in a negative direction by 8mV but the time constants of fast inactivation were little affected by cibenzoline. Cibenzoline blocks the I_kr-like current reconstituted by HERG clone transfection with an IC₅₀ value comparable to therapeutic concentrations. Cibenzoline has a preferential affinity, at least, to the open state of the HERG channel with a rapid access to the binding site.     

Inhibitory effect of green tea catechins in combination with sucralfate on <Emphasis Type="Italic">Helicobacter pylori</Emphasis> infection in Mongolian gerbils

Background The occurrence of antibiotic-resistant Helicobacter pylori has been reported. It is desirable to develop an effective method to prevent the occurrence of resistant strains of Helicobacter pylori. Green tea catechins (GTCs) have been reported to have an antibacterial effect. Therefore, the possibility of eradicating Helicobacter pylori by the oral administration of GTCs was investigated.Methods Solutions of GTCs and solutions of GTCs adsorbed to sucralfate (GTC-scf), at concentrations of 20mg GTCs and/or 20mg sucralfate/ml were prepared. Then 1ml of the GTC-scf or the GTC solution was administered daily, for 10 days to Mongolian gerbils infected with Helicobacter pylori. Then the stomachs were extirpated and homogenized. The homogenate was spread on selective medium plates. After 5-day culture, colony-forming units (CFU) of Helicobacter pylori were counted.Results The CFU of Helicobacter pylori was significantly decreased by GTC-scf.Conclusions GTC-scf may have a bactericidal effect on Helicobacter pylori infection.     

Remarkable response to rituximab in a patient with atypical CD20<Superscript>++</Superscript> mantle cell lymphoma of the bone marrow leading to severe pancytopenia

Rituximab, a chimeric monoclonal antibody which binds to the CD20 antigen, has been reported in several studies to induce remissions in low- and high-grade non-Hodgkins lymphoma without causing myelosuppression. We report here a case of a 68-year-old female patient with an atypical mantle cell lymphoma infiltrating only the bone marrow without leukemic involvement or any other nodal or extranodal manifestations. Progressive severe pancytopenia due to the diffuse bone marrow infiltration led to life-threatening infections following oral chlorambucil treatment. No response to chlorambucil was noted. The patient attained a complete remission after salvage therapy with four weekly infusions of single-agent rituximab at a standard dose of 375 mg/m². Thus, anti-CD20 antibody may be the treatment of choice for patients with CD20⁺ B-non-Hodgkins lymphoma who cannot tolerate chemotherapy due to high risk of infectious complications as a result of severe pancytopenia.     

Relaxant effect of omeprazole and lansoprazole in guinea pig gallbladder muscle strips in vitro

Background. The aim of this study was to investigate the role of omeprazole and lansoprazole, H⁺-K⁺ ATPase inhibitors, in gallbladder smooth muscle contractility in vitro. Methods. Gallbladder muscle strips obtained from guinea pigs were mounted in an organ bath. The responses of both precontracted strips and strips under basal tension to omeprazole and lansoprazole were determined. Results. Spontaneous contractile activity was blocked following omeprazole and lansoprazole administration. The agents also caused concentration-dependent relaxation in carbachol- and KCl-precontracted gallbladder muscle strips. Pretreatment with atropine (1µM), N^W-nitro l-arginine methyl ester (l-NAME; 30µM), indomethacin (10µM), ammonium chloride (7.5mM), sodium acetate (7.5mM), tetraethylammonium chloride (0.5mM), glibenclamide (1µM), 4-aminopyridine (0.1mM), or clotrimazole did not inhibit this relaxation. Gallbladder strips were placed in high-concentrtion potassium (80mM), calcium-free solution. The contraction produced with the addition of Ca²⁺ (2.5mM) was completely relaxed by omeprazole, lansoprazole, and nifedipine separately. Conclusions. These results demonstrate that omeprazole and lansoprazole have potent inhibitory effects on spontaneous contractions and cause dose-dependent relaxation in precontracted gallbladder smooth muscle strips of guinea pig in vitro. This effect could be due to blockade of the calcium channels.     

[35S]methionine interaction with rat liver tRNA and effect of chemical carcinogens

The interaction of [³⁵S]methionine with hepatic tRNA in normal, carcinogen-treated, and partially hepatectomized rats was studied. tRNA was preferentially labeled following [³⁵S]methionine (1.6 mCi, 25 mg/kg body wt) administration by intraperitoneal injection. The extent of [³⁵S]methionine-tRNA interaction was impaired by partial hepatectomy and by conditions having a carcinogenic potential.Presented at the Proceedings of the International Meetings on Normal and Neoplastic Growth in Hepatology, Bari, Italy, June 1989.Supported by CNR, Progetti Finalizzati Chimica Fine ed Oncologia     

Alanine Prevents the Decrease of Na+,K+-ATPase Activity in Experimental Phenylketonuria

Our objective was to investigate the effect of alanine administration on Na⁺,K⁺-ATPase activity in cerebral cortex of rats subjected to chemically-induced phenylketonuria. Wistar rats were treated from the 6th to the 28th day of life with subcutaneous injections of either 2.6 mol alanine or 5.2 mol phenylalanine plus 2.6 mol -methylphenylalanine per g body weight or phenylalanine plus -methylphenylalanine plus alanine in the same doses or equivalent volumes of 0.15 M saline. The animals were killed on the 29th or 60th day of life. Synaptic plasma membrane from cerebral cortex was prepared for Na⁺,K⁺-ATPase activity determination. The results showed that alanine injection prevents the decrease of Na⁺,K⁺-ATPase activity in animals subjected to experimental phenylketonuria. Therefore, in case the same effects are achieved with ingested alanine, it is possible that alanine supplementation may be an important dietary adjuvant for phenylketonuric patients.     

Serum Levels of α1-Antitrypsin Predict Phenotypic Expression of the α1-Antitrypsin Gene

We conducted a retrospective analysis to determine if both ₁-antitrypsin serum level and phenotype need be studied when evaluating children for ₁-AT deficiency. We collected data from patients less than 19 years old who had both serum ₁-AT level and phenotype determined over a 9-year period (January 1992–December 2000). Eighty-eight patients were identified and 15 had the PiZZ phenotype. The serum ₁-AT level was below normal (normal 85–215 mg/dl) in all 15 PiZZ patients. Seventy-two of 73 non-PiZZ patients had normal or above normal serum levels. The sensitivity of the serum ₁-AT level was 100%, and the specificity was 99%. The serum ₁-AT level had a positive predictive value of 94% and a negative predictive value of 100%. We conclude that serum ₁-AT levels are highly predictive of the PiZZ phenotype. Determination of the serum ₁-AT level alone should be the initial test when evaluating for ₁-AT deficiency.     

Symptoms in chronic constipation

OBJECTIVES: This study was designed to evaluate whether detailed symptom analysis would help to identify pathophysiologic subgroups in chronic constipation. METHODS: In 190 patients with chronic constipation (age, 53 (range, 18–88) years; 85 percent of whom were women), symptom evaluation, transit time measurement (radiopaque markers), and functional rectoanal evaluation (proctoscopy, anorectal manometry, defecography) were performed. Patients were classified on the basis of objective data from all tests in four different groups (disordered defecation, slow gastrointestinal transit, disordered defecation combined with slow-transit stool, and no pathologic finding). RESULTS: In 59 percent of patients, disordered defecation was found, and 27 percent had slow-transit stool. In 6 percent of patients, a combination of both was found; in only 8 percent of patients, there were no pathologic findings. Straining was reported by the vast majority in all groups (82–94 percent). Infrequent bowel movements and abdominal bloating were more common in slow-transit stool (87 and 82 percentvs. 69 and 55 percent, respectively; bothP<0.01). Feeling of incomplete evacuation was more common in disordered defecation (84vs. 46 percent;P<0.0001). However, specificity of these symptoms was discouraging (for slow-transit stool: infrequent bowel movements had a sensitivity of 87 percent and a specificity of 32 percent and abdominal bloating had a sensitivity of 82 percent and specificity of 45 percent; for disordered defecation: feeling of incomplete evacuation had a sensitivity of 84 percent and a specificity of 54 percent). Only the sense of obstruction and digital maneuvers were acceptably specific (79 and 85 percent, respectively) for disordered defecation, but sensitivity was low. CONCLUSIONS: Definition of chronic constipation by infrequent bowel movements alone is of little value; the symptom necessity to strain is much better suited (94 percent sensitivity). Specificity of infrequent bowel movements for slow-transit stool was discouraging. Sense of obstruction and digital manipulation for evacuation are relatively specific for disordered defecation but insensitive. Therefore, symptoms of chronically constipated patients are not well suited to differentiate between the pathophysiologic subgroups suffering chronic constipation.Supported by Deutsche Forschungsgemeinschaft DFG, Bonn, Germany, Grant Mu 629/2-3.     

Deleterious effects of digitalis on reperfusion-induced arrhythmias and myocardial injury in ischemic rat hearts: possible involvements of myocardial Na+ and Ca2+ imbalance

Summary Isolated rat hearts were made ischemic for 25 min after an initial recirculating perfusion, followed by 30 min of reperfusion. In some hearts, interventions including administration of ouabain and/or high [K⁺] in the buffer were performed during the first 10 min of reperfusion.During ischemia, intracellular Na⁺ (Na_i) increased from 15 to 64 [mol/g dry weight (dwt). During reperfusion, Na_i declined rapidly (at 10 min of reperfusion: 48 nol/g dwt, at 30 min: 25 mol/g dwt) and regular rhythm was recovered within 10 min in hearts without any intervention during reperfusion.⁴⁵Ca²⁺ uptake increased from 0.8 to 7.5 mol/g dwt after 30 min of reperfusion. Ventricular function recovered by 45 %.A 10-min perfusion with 10 or 50 M of ouabain increased Na_i (17 to 21 or 27 mol/g dwt) with increased left-ventricular (LV) contractile function, but these effects were reversed by combination of high perfusate [K⁺] (20 mM) in non-ischemic hearts.A 10-min reperfusion with ouabain retarded or stopped the decline in Na_i (at 10 min of reperfusion: 54 or 63 mol/g dwt, at 30 min: 32 or 40 mol/g dwt). These amounts of ouabain also increased the incidence of ventricular tachyarrhythmias during reperfusion to 30 % or 50 %, and increased the duration of ventricular fibrillation from 6.5 to 11.5 or 18.0 min.⁴⁵Ca²⁺ uptake reached to 8.8 or 10.0 mol/g dwt, and function recovered only 35 % or 28 %. When high perfusate [K⁺] was combined with ouabain during reperfusion, the retarded decline in Nai, augmented⁴⁵Ca²⁺ uptake, and reduced recovery of function caused by ouabain alone were attenuated. These results suggest that digitalis has toxic effects on reperfused ischemic hearts by inhibition of rapid active outward transport of previously elevated Na_i and potentiation of Ca²⁺ overload.The work was supported in part by grant HL 37936 from the National Heart, Lung and Blood Institute. J. R. Neely was deceased on November 29, 1988