[Arterioportal fistulas in the extra-hepatic circulation of the common hepatic artery. Diagnosis and radiologic interventional therapy]

Two cases of arterioportal fistulas and new possibilities in diagnosis and treatment are reported: A 62-year-old women was admitted to our hospital with abdominal pain. Color flow duplex sonography showed an arterioportal fistula between the proper hepatic artery and the ectatic portal vein that was confirmed by angiography, permitting percutaneous embolization as a definitive treatment. The pain disappeared immediately. A 36-year-old man underwent surgery due to a penetrating gastric ulcer. He was referred to us with an abdominal murmur. Color flow duplex sonography proved by spiral CT with 3D reconstruction and maximum intensity projection (angio-CT) revealed an arteriovenous fistula between the gastroduodenal artery and a mesenteric branch. Angiography confirmed the diagnosis and permitted definitive therapeutic embolization.

[Observation and analysis of postburn changes in substance P (SP) and SP peptidergic nerve fibers in the intestine of rat]

Substance P (SP) was measured by radioimmunoassay (RIA) and SP peptidergic nerve fibers were identified by Immunohistochemistry (IHC) in the intestinal wall of rats (TBSA 30% and with full-thickness burn) during 72 hours after burn. The results were as follows: (1) SP increased significantly at 1 hr and 4 hr postburn, then decreased markedly 8 hr later, and the low was maintained up to 72 hr. (2) The significant changes in SP peptidergic nerve fibers in the villi after burn were found with immunohistochemical studies including the morphology, distributive densities and SP contents of the SP peptidergic nerve fibers. The results from image analysis showed that the distributive densities of the nerve fibers elevated distinctly in 1 hr group, then dropped at 8 hr and 12 hr and finally elevated again. The results indicated that, the SP release might occur leading to SP consumption in the intestinal wall of rats after burn. It is possible that SP contributes to the postburn intestinal lesion in rats. The SP peptidergic nerve fibers in villus have a direct effect on the damage of intestinal mucosal barrier.

[Response and mechanism of vasovagal syncope induced by tilt table test]

Tilt table test (TTT) is done in 110 cases of unexplained syncope and 37 healthy controls. As a result, there is no significant difference in basal diastolic blood pressure (DBP), basal heart rate (HR) x DBP among TTT positive, TTT negative and healthy controls; but DBP and HR x DBP of TTT positive patients at the instant of syncope is not significantly different from their basal values, the HR at the instant of syncopy statistically in not different from the basal HR. These data suggest that not the same mechanism is responsible for the changes of BP and HR. In seventy percent of the TTT positive patients vasovagal syncope (VS) may be provoked by isoproterenol. So the occurrence of VS may be related to hypersensitivity of beta-receptor. TTT may be an approach to unravel the pathogenesis of VS.

[Effect of dl-3-n-butylphthalide (NBP) on purine metabolites in striatum extracellular fluid in four-vessel occlusion rats]

The effects of NBP on concentrations of some purine metabolites in extracellular fluid of rat striatum during global ischemia and reperfusion were studied. Global ischemia was produced by the four-vessel occlusion method. Push-pull cannula was implanted stereotaxically into the striatum of rat and was perfused with Ringer's solution at a flow rate of 2.5 microliters.min-1. The level of adenosine(Ade), inosine(Ino), hypoxanthine(Hyp) and xanthine(Xan) in perfusates were measured with HPLC connected with a UV detector. The results indicate that the levels of ade, ino, hyp and xan were significantly increased (about 3-5 times of initial value) during cerebral ischemia and reperfusion. NBP at the dose of 20 or 40 mg.kg-1 given intra-peritoneally 20 min before ischemia was shown to depress the increase of ade, ino, hyp and xan during ischemia and reperfusion dose dependently. But no change in the level of purine metabolites was found in sham operated rats. It has been known that harmful free radicals were produced when xan and uric acid were formed by xanthine oxidase during reperfusion. This might be important for the development of ischemic injuries. Our findings suggest that the effect of NBP might be beneficial for protection against post-ischemic neuronal damage.

[Effect of dl-3-butylphthalide on the striatum extracellular amino acid and dopamine contents in the rat during cerebral ischemia]

The effect of dl-3-butylphthalide (NBP) on the contents of amino acids and dopamine in the rat striatum during globe cerebral ischemia has been studied. By using the technique of microperfusion in the striatum of rats subjected to 4-vessel occlusion cerebral ischemia, the extracellular contents of glutamate, taurine, gamma-aminobutyric acid and dopamine were found to be significantly increased in the striatum during the 20 min of cerebral ischemia. NBP (40 mg.kg-1; i.p. 30 min before ischemia) was shown to reduce the contents of dopamine and its metabolite, 3,4-dihydroxyphenylacetic acid (DOPAC), in the striatal extracellular fluid of the rat during ischemia. The content of glycine before and after ischemia was also reduced. However, no significant effect on the contents of glutamate and some other amino acids was observed. The results suggest that NBP may improve the striatal ischemic injury.

Transseptal methods for percutaneous balloon valvoplasty simultaneously with radiofrequency catheter ablation

Percutaneous balloon mitral valvoplasty (PBMV) and radiofrequency catheter ablation (RFCA) have been used in the treatment of mitral stenosis (MS) and supraventricular tachycardia. The techniques of PBMV and RFCA yield better results with the development of interventional cardiology, but there is no report about PBMV performed simultaneously with RFCA in the same patient. Seven patients with mitral stenosis and Wollf-Parkinson-White (W-P-W) Syndrome were successfully treated with PBMV and RFCA by transseptal methods. LA, LAP, mPG and mPA were decreased from 43.4 +/- 4.6mm, 21.8 +/- 6.8mmHg, 21 +/- 7.7mmHg and 45.7 +/- 16.5mmHg to 39.2 +/- 3.7mm (P < 0.05), 12.7 +/- 4.5mmHg, 12 +/- 3.7mmHg and 32.3 +/- 9mmHg (P < 0.01). MVA was increased from 0.96 +/- 0.33cm2 to 1.7 +/- 0.80cm2 (P < 0.01). delta wave disappeared in 12-lead surface EKG and SVT could not be induced in electrophysiological study after the treatment. The overall time of the procedure for this series was 93 +/- 34 minutes and fluoroscopy time was 23 +/- 7 minutes on the average. Radiofrequency energy applications were 3 +/- 2 times each procedure. PBMV and RFCA are safe and highly effective in the treatment of MS and W-P-W syndrome. The results in the present study proved the feasibility of the combined use of PBMV and RFCA. We prefer a first choice of PBMV and then RFCA in order to avoid aggravation of the hemodynamics due to mitral stenosis. The results also showed that of overall procedure and fluoroscopy only took a short time for this series. We suggest that it could be used as a routine method for the treatment of mitral stenosis complicated by W-P-W syndrome.

[Scavenging effects of daphnetin and its Cu, Zn complexes on superoxide radical]

The scavenging effects of daphnetin (D) and its Cu, Zn complexes on superoxide radical (O2-.) generated through the photooxidation of riboflavin were studied with human red blood cells (RBC) and RBC membrane as experimental material. The Cu ( II ) complex showed the highest activity. SOD, D and its Cu ( II ), Zn ( II ) complexes were found to have inhibitory effect on the production of lipid peroxide in the membrane, SOD being the best among them.

Flow cytometric assay for cytotoxic activity of crude Clostridium perfringens enterotoxin using non-adherent cell FM3A

The flow cytometric assay method was tested for the cytotoxic activity of Clostridium perfringens enterotoxin (CPE) in culture using mouse mammary carcinoma cell line FM3A stained with propidium iodide (PI). From the results obtained, FM3A cells proved to be susceptible to CPE. A reproducible dose-response curve with FM3A was obtained between crude CPE at 13.9-109 ng/ml and between purified CPE at 40-400 ng/ml, respectively. These findings indicate that non-adherent FM3A is preferable to determine the cytotoxic activity of CPE because it can be used without detachment procedures with trypsinin compared with adherent African monkey kidney cell line (Vero cells). Furthermore, the flow cytometry with non-adherent cell FM3A stained with PI only proved to be a useful method to determine the biological activity of CPE in culture isolates.

[Predictive values for slow pathway modification of atrioventricular nodal reentrant tachycardia]

The predictive values of various ECG parameters for slow pathway modification were studied in 42 slow-fast AVNRT patients. The negative predictive values of a stable ECG, junctional rhythm, and slow pathway potential were as high as 94.8%, 94.9% and 84.9% respectively. But, their positive values were 29.4%, 15.1% and 23.9%. The possibility of success (PS) raised with increasing of width and peak number of A wave. When the width of A wave was > or = 80ms, PS was 50%. When the peak number of A wave was > 7, PS was 80%. A/V ratio varied from 0.14 to 1 in 93.2% of successful sites. When A/V ratio was 0.25, PS reached its peak value of 33.3%.

A simple test of the vicarious trial-and-error hypothesis of hippocampal function

Vicarious trial-and-error (VTE) is a term that Muenzinger and Tolman used to describe the rat's conflict-like behavior before responding to choice. Recently, VTE was proposed as a mechanism alternative to the concept of "cognitive map" in accounts of hippocampal function. That is, many phenomena of impaired learning and memory related to hippocampal interventions may be explained by behavioral first principles: reduced conflicting, incipient, pre-choice tendencies to approach and avoid. The nonspatial black-white discrimination learning and VTE behavior of the rat were investigated. Hippocampal-lesioned and sham-lesioned animals were trained for 25 days (20 trials per day) starting at 60 days of age. Each movement of the head from one discriminative stimulus to the other was counted as a VTE instance. Lesioned rats had fewer VTEs than sham controls, and the former learned much more slowly or never learned. After learning, VTE frequency declined. Male and female rats showed no significant differences in VTE behavior or discrimination learning.

[Effects of interferon treatment on mutation of hepatitis B virus precore genome]

Effects of interferon (IFN) treatment on mutation of hepatitis B virus (HBV) precore were studied with a rapid polymerase chain reaction method to investigate the stop codon in the distal precore region during HBV precore mutation. 6 cases of chronic hepatitis B were treated with recombinant IFN alpha 1 3 x 10(6) U/day for 14 weeks. In 4 of them HBV DNA was undetectable after treatment. Precore mutant was detected in the remaining 2 cases whose HBV DNA was still positive. In a group of 11 cases not treated with IFN, mutants were detected in 3. HBV e antigen (HBeAg) became negative after IFN treatment in one case, the original wild strain was replaced by a status of co-existence of mutant and wild strain. These results suggest that HBeAg negative seroconversion after IFN treatment does not necessarily implicate a complete clearance of HBV and the possibility of mutation of precore still exists.

Interactions of human nuclear proteins P1Mcm3 and P1Cdc46

Human nuclear proteins P1Mcm3 and P1Cdc46 have high sequence similarities with the corresponding yeast proteins known to be required for the initiation of genome replication. Nuclei of proliferating HeLa cells contain relatively high amounts of P1Mcm3 (about 10(6) molecules/nucleus) of which only a small fraction is bound to a nuclear structure, most probably chromatin. At 0.5 M NaCl, the structure-bound nuclear protein can be partially solubilized as a dimer composed of P1Mcm3 and the related protein P1Cdc46. However, most protein P1Mcm3 is not bound to a nuclear structure and appears in the nucleoplasm. About 10% of protein P1Mcm3 in the soluble fraction is free and uncomplexed, and the remaining P1Mcm3 forms stable complexes with protein P1Cdc46. These P1Mcm3/Cdc46 complexes occur as dimers and in high-molecular-mass complexes (approximately 500 kDa). The high-molecular-mass complexes dissociate in 0.5 M NaCl and release P1Mcm3/Cdc46 dimers. It has frequently been proposed that the Mcm proteins may function as licensing factors for genome replication. Our data imply that the active form of an Mcm protein is not a monomer, but a protein complex that includes an Mcm3/Cdc46 dimer. DNA polymerase alpha is not a component of this complex.

Building synthetic antibodies as adhesive ligands for integrins

An antibody engineering strategy was employed to build high affinity ligands and antagonists of integrins alpha v beta 3 and alpha IIb beta 3. Previously, we inserted the integrin recognition motif, RGD, into the antigen binding site of a human antibody and selected the optimal flanking sequences from a phage-display library (Barbas, C. F., Languino, L. R., and Smith, J. W. (1993) Proc. Natl. Acad. Sci. U.S.A. 90, 10003-10007). The resulting antibody, Fab-9, blocked the function of integrin alpha v beta 3 but also bound to the ligand binding site of platelet integrin alpha IIb beta 3. In this report, the antibody engineering effort has been extended by 1) redesigning Fab-9 to achieve specificity for platelet integrin alpha IIb beta 3, 2) building non-RGD-containing antibodies that bind the ligand binding site of both beta 3-integrins, and 3) testing the hypothesis that peptides derived from complementarity determining regions (CDR) can be used to emulate the activity of the parent synthetic antibody. These goals were accomplished by subjecting the original antibody, Fab-9, to a "motif optimization" (MTF). A phage library was constructed in which the residues flanking the RGD motif in Fab-9 were maintained, but the RGDX sequence was randomized. This library was panned on purified alpha IIb beta 3 to identify high affinity binders. Four function-blocking antibodies lacking RGD, but with specificity for alpha IIb beta 3, were characterized. The antibody with the highest preference for alpha IIb beta 3, MTF-10, had an adhesion sequence of KGDN. This sequence is similar in primary structure to the active sequence within the disintegrin barbourin, which also antagonizes alpha IIb beta 3 (Scarborough, R. M., Rose, J. W., Hsu, M. A., Phillips, D. R., Fried, V. A., Campbell, A. M., Nannizzi, L., and Charo, I. F. (1991) J. Biol. Chem. 266, 9359-9362). MTF-10 had a 70-fold higher affinity for alpha IIb beta 3 than alpha v beta 3. Through our selection strategy, we also identified several antibodies that lack RGD but still blocked ligand binding to both integrins with high affinity. Therefore, the RGD sequence is not necessary for a high affinity interaction with the ligand binding site of beta 3-integrins. Further investigation showed that the activity of inhibitory antibodies could be emulated by synthetic peptides derived from the protein sequences of the antibody's HCDR3. CDR-derived peptides blocked ligand binding to integrins and maintained essentially the same specificity as the parent antibody.

Sensitivity of United States HIV antibody tests for detection of HIV-1 group O infections

Infections by highly divergent strains of HIV-1, first detected in central Africa and grouped provisionally as group O, have not been reliably detected by certain European HIV screening tests. Serum specimens from eight probable group O infections from Cameroon were tested by ten HIV assays licensed by the US Food and Drug Administration. All assays based on synthetic peptides or recombinant antigens failed to detect at least one of the infections; assays based on whole-virus lysates performed better. Divergent HIV strains may be undetected by current HIV tests. Thus active surveillance for and characterisation of HIV variants to evaluate and, when necessary, modify current tests is urgently needed.

Postlicensure effectiveness of the Haemophilus influenzae type b polysaccharide-Neisseria meningitidis outer-membrane protein complex conjugate vaccine among Navajo children

The incidence of invasive Haemophilus influenzae type b (Hib) infection was decreased significantly among Navajo children since the licensure of Hib conjugate vaccines, even though two lots of Hib (polyribosylribitol phosphate)-meningococcal B outer-membrane protein conjugate vaccine (PRP-OMP) widely used among the Navajo were later found to be of low immunogenicity. We measured the effectiveness of all Hib conjugate vaccines combined, PRP-OMP alone, and the PRP-OMP lots with lower-than-expected immunogenicity among Navajo infants and children. This was a matched case-control study using active, laboratory-based surveillance for the ascertainment of Navajo children 2 1/2 to 59 months of age with invasive Hib infection; 45 patients with infection and 180 control subjects were enrolled. The effectiveness of one, two, and three doses, respectively, of all Hib conjugate vaccines combined was 96% (95% confidence interval (CI) 65%, 99%), 99% (95% CI, 69%, 100%), and 99% (95% CI - 57%, 100%). The effectiveness of one or more doses of PRP-OMP was 95% (95% CI, 66%, 99%). The effectiveness of a single dose of the lots of lower-than-expected immunogenicity was 89% (95% CI, -8%, 99%). The Hib conjugate vaccine coverage increased from 49% during 1991 to 94% during 1992; no control subjects younger than 18 months of age were enrolled during 1993. The occurrence of invasive Hib infections in this population after licensure of Hib conjugate vaccines was the result of gradual vaccine uptake, not poor vaccine effectiveness. The use of PRP-OMP has been highly effective despite concerns about the immunogenicity of several lots.

Predictors of early and late recurrence of atrioventricular accessory pathway conduction after apparently successful radiofrequency catheter ablation

The correlation between electrophysiologic parameters and recurrence in 239 patients who underwent successful catheter ablation for an accessory pathway mediated tachycardia was analysed. Pathway conduction recurred in 15 patients (6.3%) after a mean follow-up of 7.3 months. Recurrence was most common in patients with right free wall pathways (17.1%). Accessory pathway conduction resumed in 18.9% of patients with decremental ventriculo-atrial (VA) conduction post-ablation compared with those patients without VA conduction (3.4%) (P < 0.001). Recurrence was common also in patients with repeated return of accessory pathway conduction during the ablation procedure (40% vs. 1.3%, P < 0.01). The patients in whom these observations are made should be monitored closely for recurrence of accessory pathway conduction post-ablation.

Epidural analgesia in labor and cesarean delivery for dystocia

Published studies assessing the effect of epidural analgesia in nulliparous labor on the frequency of cesarean delivery for dystocia are reviewed. There are at least four retrospective studies and two prospective studies that suggest that epidural analgesia may increase the risk of cesarean delivery for dystocia in first labors. The potential for epidural to increase the frequency of cesarean delivery for dystocia is likely influenced by multiple variables including parity, cervical dilatation at epidural placement, technique of epidural placement, management of epidural during labor, and the obstetrical management of labor after placement of epidural analgesia. Two studies suggest that delaying placement of the epidural until 5 cm of cervical dilatation or greater may reduce the risk of cesarean birth. Epidural is safe and may be a superior labor analgesic when compared with narcotics. However, patients should be informed that epidural analgesia may increase the risk of cesarean birth in first labors.

In vitro evolution of a neutralizing human antibody to human immunodeficiency virus type 1 to enhance affinity and broaden strain cross-reactivity

A method is described that allows for the improvement of antibody affinity. This method, termed complementary-determining region (CDR) walking, does not require structural information on either antibody or antigen. Complementary-determining regions are targeted for random mutagenesis followed by selection for fitness, in this case increased binding affinity, by the phage-display approach. The current study targets a human CD4-binding-site anti-gp120 antibody that is potently and broadly neutralizing. Evolution of affinity of this antibody demonstrates in this case that affinity can be increased while reactivity to variants of human immunodeficiency virus type 1 is broadened. The neutralizing ability of this antibody is improved, as assayed with laboratory and primary clinical isolates of human immunodeficiency virus type 1. The ability to produce human antibodies of exceptional affinity and broad neutralizing ability has implications for the therapeutic and prophylactic application of antibodies for human immunodeficiency virus type 1 infection.

[A community cohort study on risk factors of strokes in Shanghai: a Cox regression analysis on 15,885 subjects]

Baseline investigation on 15,885 subjects who were over thirty-five years old had been launched since July 1987. All of them were selected from eighteen neighbourhoods of three districts in Shanghai by using multiple stage cluster sampling procedure. All of them were followed up till the end of 1989. Each new case of stroke was randomly matched with about twenty controls by age and sex. The total 2,682 controls together with 127 new cases of strokes were analyzed by using Cox regression model for risk factors. The population attributable risk proportion (PARP) of factors was also estimated.

Retrograde conduction properties after catheter radiofrequency ablation of atrioventricular accessory pathways

A total of 208 atrioventricular (AV) accessory pathways in 200 patients were abolished by catheter radiofrequency current ablation. The antegrade AV conduction was normal after the ablation. Approximately 66% of the patients experienced retrograde AV conduction dissociation, which is independent of the age, gender and antegrade conduction properties of accessory pathways (manifest or concealed). Retrograde conduction dissociation is more prevalent than decremental conduction in patients with left free (80% vs. 17%, P < 0.001) or right free (78.6% vs. 21.4%, P < 0.01) wall pathways. Eleven patients (5.5%) showed recurrence after an average of 213 days follow-up. The recurrence of right free wall pathways (21.4%) is much more common than that of left free wall (2.5%) and posteroseptal (4.8%) pathways. The recurrence in those with decremental conduction after the initial successful ablation is higher than that of patients with retrograde AV dissociation (8.8% vs. 3.8%, P < 0.01), and most of them required a second ablation session.

CONCLUSION

most of the patients, especially those with free wall accessory pathways, will have retrograde conduction dissociation after the successful radiofrequency catheter ablation. Electrophysiological studies should be carefully performed on patients with decremental retrograde conduction after the ablation.

Metachromatic leukodystrophy in the Navajo Indian population: a splice site mutation in intron 4 of the arylsulfatase A gene

Metachromatic leukodystrophy (MLD) is an autosomal recessive disorder of myelin metabolism, resulting from the inability to properly degrade 3-sulfogalactosylceramide (sulfatide). This metabolic block is often due to defective functioning of the lysosomal enzyme arylsulfatase A (ARSA). Unmetabolized sulfatide accumulates in the white matter of the CNS and in the peripheral nerves, leading to progressive demyelination and death. Late infantile, juvenile and adult clinical variants of MLD have been described. A Navajo Indian child was diagnosed with late infantile MLD (LIMLD), and his ARSA gene was amplified in three overlapping regions by the PCR and sequenced. A single mutation was found: a G-->A transition in the first nucleotide of intron 4 (IVS4nt1), which abolishes the 5' splice site consensus sequence. Negligible amounts of ARSA mRNA were observed in Northern blots. However, PCR amplification and sequencing of the ARSA cDNA showed that all of the mRNA species from the patient have exon 4 deleted. A new reading frame is thus established which results in a premature stop codon within exon 5. A minority of transcripts had additional splicing errors. Both parents carry this mutation, and the father also carries the pseudodeficiency (PD) allele. Three additional unrelated Navajo LIMLD patients were found to be homozygous for the same MLD-causing mutation by allele-specific oligonucleotide (ASO) hybridization. This method could be used for carrier and patient identification in this population.

Catheter ablation of atrioventricular accessory pathways by radiofrequency current

Tachycardias mediated by atrioventricular accessory pathways, which are refractory to antiarrhythmic drug therapy have been treated both by surgery and by catheter ablation with high energy direct current shock. These procedures have variable success rates and substantial associated morbidity and mortality. Radiofrequency ablation, a newer, low-energy technique is potentially safer and more effective. Of 110 patients with 117 accessory pathways, 101 were located on the left side and 16 on the right. Accessory pathway conduction was abolished permanently in 101 (91.8%) patients. VA conduction dissociation and VA decremental conduction were found in 88 and 13 successful patients, respectively. Four (3.9%) patients with decremental VA conduction suffered arrhythmia recurrence after a mean of 8 months follow-up. Complications developed in two patients including right femoral vein thrombosis and left ventricular insufficiency. There were no deaths from the procedure. We conclude that radiofrequency current ablation is a safe and effective interventional modality for patients with symptomatic tachycardias mediated by atrioventricular accessory pathways.

Binding of IgG to amyloid beta A4 peptide via the heavy-chain hinge region with preservation of antigen binding

Amyloid beta A4 peptide is found in the extracellular region of the senile plaque and in the angiopathy of Alzheimer's disease. Several other proteins, including IgG, also reside in these abnormal structures. In an attempt to understand how these structures are assembled and to determine how proteins are recruited, interactions of various proteins with synthetic beta A4 peptide have been examined in vitro. Purified IgG binds directly to synthetic beta A4 peptide with high avidity. The domain between amino acids 12-28 of beta A4 binds IgG. beta A4 peptide binds the hinge region of the immunoglobulin heavy chain, and preserves the ability of the immunoglobulin to bind antigen. A protein which does not bind directly to beta A4 peptide can be targetted to the senile plaque and angiopathy by binding to IgG, which avidly binds beta A4 peptide.

Interaction of indoleacrylic acid with Trp aporepressor from Escherichia coli

Trans-beta-Indoleacrylic acid (IAA) binds with moderately high affinity to the dimeric protein, trp aporepressor from Escherichia coli. IAA is itself nonfluorescent, and, upon binding, IAA quenches approximately 95% of the intrinsic tryptophan fluorescence of the protein. Since there is an overlap between the absorbance of IAA and the emission of tryptophan, this quenching appears to be due to resonance energy transfer. To adequately fit binding isotherms, it was necessary to use a model in which the binding of IAA to one subunit is able to quench fluorescence from both subunits of the protein. This model also assumes that binding to the two subunits occurs independently. Binding data were obtained as a function of the concentration of trp aporepressor, over the range of 1 x 10(-8) to 5 x 10(-5) M, in order to test the possibility that protein subunit association or dissociation occurs. When analyzed in terms of the above model, no significant protein concentration dependence is seen for the IAA association constant, indicating that either (i) the protein does not undergo changes in oligomerization over this concentration range or that (ii) different states of aggregation bind IAA with similar affinity. The affinity of IAA was found to increase at higher ionic strength and at lower pH. Also, evidence is presented for a photoinduced change in the configuration of IAA.

Prolonged regional nerve blockade by controlled release of local anesthetic from a biodegradable polymer matrix

BACKGROUND

Prolonged nerve blockade is potentially useful in the management of many acute and chronic pain problems. Aside from infusions via an indwelling catheter, most currently available nondestructive techniques for prolonging local anesthetic action cannot provide more than 1-2 days of blockade. Bioerodible polymer matrixes have been used to deliver a variety of drugs in patients and animals for periods lasting weeks to years. Previously, dibucaine and bupivacaine were incorporated into copolymers of 1,3 bis(p-carboxyphenoxy) propane-sebacic acid anhydride (1:4), and demonstrated sustained release in vitro following incubation of the drug-polymer matrixes in phosphate-buffered solution (pH 7.4, 37 degrees C).

METHODS

In the present study, cylindrical pellets made from polymer matrixes incorporated with bupivacaine-HCl were implanted surgically along the sciatic nerves of rats. Neural block was assessed by direct observation of motor skills and by leg-withdrawal latency to a hot surface. Biochemical and histologic examinations were performed 2 weeks after implantation.

RESULTS

Sensory and motor blockade was produced for periods ranging from 2 to 6 days. Contralateral control legs receiving polymer implants without drug showed no block. Blockade was reversible, and animals appeared to recover sensory and motor function normally. Biochemical indexes of nerve and muscle function were indistinguishable from contralateral controls.

CONCLUSIONS

This biodegradable polymer system provides a promising new alternative for the delivery of local anesthetics to peripheral nerves to produce prolonged blockade for the management of acute and chronic pain.

Studies on antibiotic 230 as a molluscicide

In the course of studying molluscicidal effects of microorganisms, a microorganism belonging to Streptomycetaceae, Streptomyces griseolus (Strain 230) was isolated from soil and a certain microbial ingredient proved to have a molluscicidal activity. The effective substance was named antibiotic 230. As a result of several investigations on the antibiotic, the following chemical features were made clear. The chemical substance was an indol-carbazole-heterocyclic compound, the molecular weight 446 and the molecular formula C28H26N4O3. The antibiotic demonstrated a molluscicidal effect against Oncomelania snails and their eggs both in the laboratory and in the field. The compound had a wide bacteriostasis spectrum and a slight toxicity to fish in addition to the above, but it was non-toxic to plants.

[HPLC--detection of hydroxyl radicals in striatum extracellular fluid in rats subjected to reperfusion after cerebral ischemia and the action of vitamin E]

The formation of hydroxyl radical in the extracellular fluid in striatum of rats subjected to 4-vessel occlusion during ischemia and reperfusion was measured by HPLC with UV detector using salicylic acid as a trapping agent. Hydroxyl radicals react with salicylic acid yielding 2,3- and 2,5-dihydroxybenzoic acids which can be separated by liquid chromatography. The striatum was perfused with artificial cerebrospinal fluid containing 0.5 mmol.L-1 salicylic acid at a flow rate of 2.5 microliters.min-1. The results indicate that the concentration of 2,5-dihydroxybenzoic acid in the perfusates was highest during 25 min reperfusion and no change was found during ischemia. Vit E at 30, 60 and 120 mg.kg-1 i.p. 20 min before ischemia was shown to dose dependently suppress the rise of 2,5-dihydroxybenzoic acid after reperfusion. The results suggest that the HPLC method is useful and reliable for the measurement of hydroxy radical in global ischemia in vivo.

A highly sensitive enzyme-linked immunosorbent assay for Clostridium perfringens enterotoxin

A highly sensitive enzyme-linked immunosorbent assay (ELISA) for quantitation of Clostridium perfringens enterotoxin (CPE) by a sandwich method with polystyrene beads was elaborated. The ELISA was very sensitive with a detection limit of 1 pg/ml of CPE. Clostridium perfringens culture fluid did not interfere with the assay. This ELISA may be useful for the mass screening for Cl. perfringens producing small amounts of CPE.

[A primary report on thrombolytic therapy of acute myocardial infarction in 40 cases]

Forty cases with acute myocardial infarction were treated by thrombolysis from June, 1989 through September, 1990. 32 males and 8 females. Age 44-76 (60 +/- 7.1) years. Coronary angiography was performed in 19 patients 10 days after intravenous thrombolysis on average. With intravenous thrombolysis the reperfusion rates were 69.2% (9/13) for streptokinase and 53.8% (7/13) for urokinase (Green Cross Company, Japan) according to the clinical criteria. No reperfusion was observed in 8 cases treated by China-made urokinase. The reperfusion rate of intracoronary thrombolysis was 85.7% (6/7). 5 cases had hemorrhagic complications, skin ecchymosis in 2 and mild gastrointestinal bleeding in 3, and no transfusion was necessary. No intracranial hemorrhage was noticed.

Insulin rapidly induces rat liver S14 gene transcription

We evaluated the role insulin plays in the regulation of hepatic S14 gene transcription using the streptozotocin-induced diabetic rat model. Nuclear run-on activity and mRNAS14 levels were reduced by more than 85% in diabetic rats compared to those in intact animals. After the administration of insulin, both S14 run-on activity and mRNAS14 levels were rapidly induced. Within 1 h of insulin administration, S14 run-on activity and mRNAS14 were induced 5- and 8-fold, respectively. S14 gene expression was restored to intact levels within 4 h, with overall increases in run-on activity and mRNAS14 of 7- and 20-fold, respectively. The full induction of mRNAS14 cannot be accounted for solely by activation of S14 gene transcription, implicating insulin effects at the posttranscriptional level. However, our results show that the principal target for insulin action on the S14 gene is transcriptional. Administration of dibutryl cAMP and theophylline fully blocked the insulin-mediated increase in S14 gene transcription, indicating that hepatic cAMP levels play a dominant negative role in regulating S14 gene transcription in vivo. Fructose administration to starved diabetic rats induced only a marginal 60% increase in mRNAS14 and S14 run-on activity within 4 h, while insulin plus fructose or insulin plus glucose fully restored S14 gene expression to intact levels within the same time period. Thus, dietary fructose or a metabolite generated from fructose alone cannot induce S14 gene transcription or mRNAS14 to intact levels in the starved diabetic rat. Acute effects of dietary carbohydrate on hepatic S14 gene transcription are insulin dependent.(ABSTRACT TRUNCATED AT 250 WORDS)

Dumbbell metastatic cystosarcoma phyllodes of the heart and lung

Cystosarcoma phyllodes is an uncommon breast tumor that rarely metastasizes. A case of dumbbell cystosarcoma phyllodes metastatic to the heart and lung diagnosed antemortem is described. The roles of diagnostic echocardiography and surgical excision are discussed. Atrial extension of a lung malignancy through a pulmonary vein is not an absolute contraindication to operation, but careful patient selection and operative planning are required.

Effects of clofilium on ischemic subendocardial Purkinje fibers 1 day postinfarction

One day after ligation of the canine anterior descending coronary artery, clofilium, a long-acting class III antiarrhythmic agent, was studied for its effects on normal and ischemic Purkinje fibers. In normal Tyrode's solution (4 mM potassium, 2.7 mM calcium) clofilium (10(-7) to 10(-5) M) increased action potential duration. Although only 2 of 10 normal Purkinje fibers developed early after depolarizations and early afterdepolarization-initiated triggered activity, 10 of 11 ischemic Purkinje fibers developed these features. Consequently, action potentials in ischemic fibers were prolonged to durations greater than 10 s. The triggered activity in the ischemic Purkinje fibers produced repetitive activity in adjacent normal ventricular muscle. In vivo, 3 days after ligation, the administration of 3 to 10 mg/kg clofilium induced grouped beating. Action potentials recorded subsequently from these same hearts in vitro showed early afterdepolarizations, triggered activity and a similar grouping of responses. Therefore, clofilium differentially produced early afterdepolarizations in ischemic Purkinje fibers. This is a mechanism by which clofilium could be arrhythmogenic in an ischemic heart.

Dietary obesity in rats: influence on carbohydrate metabolism

When male rats were fed a high diet from 3 to 20 weeks of age, they weighed 633 g which was 30% more than the animals fed a high glucose diet. Blood samples after a 16 to 18 hour fast, from the rats fed the high fat and high glucose diets contained, respectively: 130 +/- 11, 110 +/- 8 mg glucose/100 ml; 27 +/- 5, 24 +/- 3 microunits immunoreactive insulin (IRI)/ml; 791 +/- 58, 1104 +/- 179 meq nonesterified fatty acids (NEFA)/L. A tolerance test, by stomach tube, with 125 mg of glucose/100g body weight indicated that the rats fed the high fat diet had significantly higher mean plasma glucose concentrations, lower IRI responses and a lower leve of NEFA than rats fed a high glucose diet. Switching diets for 5 weeks resulted in body weights of about 600 g for both groups of rats. Those rats switched from the high fat to the high glucose diet did show an improved glucose tolerance, while the reverse was true of rats switched from the high carbohydrate to the high fat diet.