Neural activity and the levels of high energy phosphates during deprivation of oxygen and/or glucose in hippocampal slices of immature and adult rats

To investigate the relationship between neural activity and cerebral energy metabolism during anoxia or ischemia in neural tissue of different ages, hippocampal slices were prepared from four-, seven- and 10-day-old and adult rats. For the index of the neural activity, the population spikes were recorded in the pyramidal cell layer of the CA3 area. ATP and phosphocreatine levels in the slices were measured during oxygen and/or glucose deprivation. After deprivation of both oxygen and glucose, population spikes of the slices from four, seven- and 10-day-old and adult rats ceased completely in 14.2, 11.8, 9.4 and 5.3 min, respectively. The level of ATP at the time of cessation of population spike in four-, seven- and 10-day-old and adult rats was 37.4, 30.2, 28.5 and 56.4% of the original concentrations. After deprivation of glucose only, the decay time of the population spikes of the slices from four-, seven- and 10-day-old and adult rats was 17.8, 14.5, 9.0 and 10.0 min and at the time of population spikes cessation the level of ATP was 99.8, 84.2, 79.3 and 49%, respectively. After deprivation of oxygen only, population spikes of the slices from four, seven- and 10-day old and adult rats ceased completely in 257, 283, 109 and 8.5 min, respectively. The level of ATP at the time of population spikes cessation was 50, 40, 36.6 and 94.4% of the initial values, respectively. These results indicate that the immature rat is extremely resistant to oxygen deprivation from a functional and a metabolic view, whereas in the adult rat, preservation of neural activity depends much on both oxygen and glucose. During glucose deprivation, population spikes of the slices of immature and mature rats ceased rapidly although the level of ATP is preserved at high levels. This suggests that glucose plays an important role in the preservation of neural activity in addition to its major function as an energy substrate especially in immature animals.

Corticosteroid therapy for ventricular tachycardia in children with silent lymphocytic myocarditis

OBJECTIVE

The objective of our study was to describe the efficacy of corticosteroids for ventricular tachycardia in four children with structurally normal hearts in whom endomyocardial biopsy revealed histologic changes of lymphocytic myocarditis.

PATIENTS

The four patients had unexplained ventricular tachycardia. Three dysrhythmias were sustained, and one was inducible by exercise. Patient ages ranged from 4 months to 12 years. Three of the four patients had no symptoms. In two of them, ventricular tachycardia was identified by mass screening for heart disease. Two patients received oral steroids and two received pulse steroid therapy.

RESULTS

In all four patients, significant underlying diseases were not found by noninvasive evaluation. Right ventricular endomyocardial biopsy revealed abnormal histologic findings of chronic lymphocytic myocarditis in all patients. Steroid therapy was effective in all four patients, two of whom received methylprednisolone pulse therapy.

CONCLUSIONS

We conclude that unexplained ventricular tachycardia may be the only manifestation of clinically silent myocarditis. Steroid therapy should therefore be considered if conventional antiarrhythmic medication is not effective and histologic findings confirm the presence of lymphocytic myocarditis.

Activity of eight fluoroquinolones against both methicillin-susceptible and -resistant Staphylococcus aureus isolated from skin infections

The in vitro susceptibility of Staphylococcus aureus to eight fluoroquinolones, norfloxacin, ofloxacin, enoxacin, ciprofloxacin, lomefloxacin, tosufloxacin, sparfloxacin, and nadifloxacin was established by agar dilution tests, 71 isolates of methicillin-susceptible (MSSA) and 74 isolates of -resistant S. aureus (MRSA) isolated from skin infections. Among all of the fluoroquinolones, nadifloxacin exhibited the lowest MIC for both MSSA and MRSA. In addition, there were no resistant S. aureus, neither MSSA and MRSA, to nadifloxacin. With the exception of nadifloxacin, the incidence of MRSA resistant to fluoroquinolones has gradually increased in recent years. Over half of the MRSA strains were resistant to norfloxacin, ofloxacin, enoxacin, ciprofloxacin, and lomefloxacin.

Disease distribution of beta 2-glycoprotein I-dependent anticardiolipin antibodies in rheumatic diseases

We investigated the clinical significance of IgG beta 2-glycoprotein I (GPI)-dependent anticardiolipin antibodies (aCL) in rheumatic diseases. Three hundred and seventeen patients were entered. They consisted of 133 patients with SLE, 60 with RA, 45 with SSc, 37 with PM, 23 with overlap syndrome (overlap), and 19 with unclassified connective tissue disease (UCTD). IgG beta 2-GPI-dependent aCL were examined by ELISA. While IgG beta 2-GPI-dependent aCL were detected in 13% of patients with SLE, these aCL were positive in two patients with SSc, two with overlap and 14 with UCTD. A significant association between IgG beta 2-GPI-dependent aCL and thrombosis was found. Clinical manifestations were studied in 32 patients with secondary APS based on SLE and 14 with primary APS (PAPS). Incidence of malar rash, arthritis, renal disorder, leucopenia, immunological disorders and hypocomplementemia were significantly less frequent in patients with PAPS. IgG beta 2-GPI-dependent aCL were detected in all patients with PAPS and in 34% of secondary APS. This difference was significant. These data suggest that IgG beta 2-dependent aCL are useful for identifying a subset in patients with APS.

One-stage treatment of infected bone defects of the tibia with skin loss by free vascularized osteocutaneous grafts

Twenty-six patients who had an infected nonunion or segmental defect of the tibia with skin loss were treated in one stage with debridement and a free vascularized osteocutaneous fibula or iliac graft. Successful control of infection, closure of skin defects, and incorporation of bone union were achieved in all patients except one. In an average follow-up of 39 months, no recurrence of infection was seen. There were four stress fractures of the grafted fibula; these healed within 2 months with cast immobilization. Graft hypertrophy was common in the fibula grafts, but it took 1 1/2 years for hypertrophy of the graft to be strong enough to remove external supports without stress fracture or an additional cancellous bone graft. The use of a one-stage free vascularized osteocutaneous graft for the management of infected bone defects of the tibia with skin loss is effective because extensive debridement can remove all devitalized and infected tissue and can increase vascularity in the region of infection and osseous defect to enhance antibiotic delivery.

Nerve regenerating effect of short-course administration of cyclosporine after fresh peripheral nerve allotransplantation in the rat: comparison of nerve regeneration using different forms of donor nerve allografts

There is almost universal agreement that if cyclosporine (CsA), which is a potent immunosuppressant, is temporarily administered after surgery, regenerated axons will be maintained even after withdrawal of CsA following peripheral nerve allotransplantation. Thus, this experimental study was conducted to investigate whether a difference in donor nerve form, including thickness and length, influences nerve regeneration after withdrawal of immunosuppression with CsA. The findings suggest that as a result of immunosuppression with CsA, large-diameter nerve grafts are better able to induce nerve regeneration than small-diameter grafts, and after withdrawal of the immunosuppressant, thick nerve grafts are also better able to preserve regenerated axons against the rejection reaction than thin grafts. With regard to the length of the grafted nerve, short nerve allografts yield higher axon counts than long ones, the same as with autografts. The best way to induce nerve regeneration appears to be to transplant a short, thick nerve allograft, which is definitely capable of inducing many regenerated axons.

The attitude of Japanese physicians regarding genetic service for autosomal dominant polycystic kidney disease (ADPKD)

A questionnaire carried out among Japanese physicians revealed that a strong demand for genetic counseling among patients and families with autosomal dominant polycystic kidney disease (ADPKD). In contrast, the awareness of physicians regarding genetic counseling for the disease seemed to be low. For example, 66.0% of the respondents to the questionnaire revealed a negative attitude to providing genetic counseling for patients, and 30.7% of the respondents did not know that most types of polycystic kidney disease are inherited disorders. With the advance of scientific research, the demand for genetic counseling among patients is bound to increase. Therefore, the providers of genetic counseling including the physicians are now pressed to improve their services.

Homologous down-regulation of the glucocorticoid receptor down-modulates cellular hormone responsiveness in human histiocytic lymphoma U937 cells

One of the determinants of cellular responsiveness to glucocorticoid hormone is the concentration of the receptor protein. It is well-known that cellular receptor levels are down-regulated by the cognate ligands, but the biological significance of this homologous down-regulation of the receptor has not yet been completely understood. We showed that in human histiocytic lymphoma cell line U937 the cellular glucorticoid receptor was homologously down-regulated by means of both ligand binding and Western immunoblot experiments. Reduction of the receptor was saturable, and the receptor levels tended to return to the levels before treatment after 3-day culture in the presence of the hormone. Next, using the cells which were pretreated with the hormone for 0 to 3 days, hormonal inducibility of the transiently-transfected reporter gene and the inhibitory effect of the hormone on cellular 3-O-methyl glucose uptake were determined. Hormonal inducibility of the reporter gene was progressively reduced, and thereafter tended to be restored, apparently in accordance with the cyclic change in amount of the receptor. The glucose uptake inhibiting effect of the hormone also revealed this cyclic pattern. In summary, in U937 cells glucocorticoid receptor was homologously down-regulated and may play a pivotal role in attenuating hormone responsiveness.

Intervertebral disc amyloidosis: histochemical, immunohistochemical and ultrastructural observations

Intervertebral discs selected at random from autopsies and surgical operations on herniated discs were examined for evidence of amyloid deposition. Amyloid deposits were detected in 53 (81.5%) of 65 autopsy cases. Discs from subjects over 50 years of age revealed a significantly high incidence of amyloid deposition. Among herniated discs, amyloid deposits were documented in 49 (75.4%) of 65 surgical specimens. The incidence of amyloid deposition in intervertebral discs increased with advancing age. Intervertebral disc amyloidosis consisted of amyloid deposits of three morphological types: linear amyloid deposits around the degenerating chondrocytes (perichondrocyte type), and nodular or band-like deposits in the annulus fibrosus (annulus fibrosus type) and nucleus pulposus (nucleus pulposus type). We suspect that the precursor protein of perichondrocyte type amyloid is derived from chondrocytes, and those of annulus fibrosus type and nucleus pulposus types are derived from the blood. The amyloid deposits were resistant to treatment with potassium permanganate. Immunohistochemically, the amyloid deposits reacted with antibody against amyloid P-component, but not with antibodies against AA, A kappa, A lambda, transthyretin or beta 2-microglobulin. Ultrastructurally, the amyloid deposits were composed of 10 nm-wide nonbranching fibrils. The amyloid in herniated discs had the same biochemical and immunohistochemical properties as those found in autopsy cases. The immunohistochemical characteristics of the amyloid deposits suggest that it derives from an, as yet, unknown precursor protein.

Vascularized allogeneic nerve transplantation with cyclosporine immunosuppression

Allogenic grafts have many advantages over autogenous grafts. An experimental rat model using the great saphenous nerve was developed to study the reconstruction of long peripheral nerve defects with vascularized allogeneic nerve grafts, and the effects of cyclosporine therapy on graft survival were assessed. In animals receiving short-term immunosuppression, the number of regenerated axons increased steadily during the treatment, but rejection began immediately after cyclosporine was discontinued. As the tissues transplanted with the nerves underwent necrosis, the grafts showed demyelination. In contrast, in animals receiving long-term cyclosporine therapy, nerve regeneration assessed in terms of the myelinated axon count was excellent until at least 12 weeks postoperatively but was less active than in vascularized autografts or conventional allografts. These results indicate that the short-term immunosuppressive therapy with cyclosporine cannot produce immunological tolerance of vascularized nerve allografts. In addition, even when administration of cyclosporine was prolonged, nerve regeneration did not exceed that in autografts.

[Chagas' disease among blood donors in Bolivia]

A questionnaire survey of blood donors at Santa Cruz General Hospital, Bolivia, showed that while there were no seropositive cases of syphilis, HBsAg, and HIV, the prevalence of Chagas' disease was very high (23%) among the 225 blood donors who responded to this questionnaire. Actual cases of Chagasic seropositive blood being used for blood transfusion were seen, including the urgent need for a program for Chagas' disease in Bolivia. From the results of this study, it is recommended that for blood donors from South American countries, the presence/absence of Chagas' disease should be confirmed.

A simple method of HLA-DRB typing using enzymatically amplified DNA and immobilized probes on microtiter plate

We have developed a simple and economical method for HLA-DNA typing, called microtiter plate hybridization (PCR-MPH), which could replace standard PCR-SSO. This method is similar to that of an ELISA. Briefly, the PCR products labeled at the 5' termini with biotin were hybridized with probes immobilized on a microtiter well, and the bound PCR products were detected by streptavidin-conjugated enzymes followed by color development. A system for HLA-DRB1 "generic" typing (e.g., DR1, DR2), using microtiter wells coated with 12 different SSOs has been established. The HLA-DRB types classified using this method agreed well with those obtained by conventional serologic typing. The advantages of this microtiter plate-hybridization method for routine HLA-DNA typing are a short assay time, easy processing of large numbers of samples, and the potential for automation.

A case of arrhythmogenic right ventricular dysplasia with atrial flutter

A 57-year-old male who had arrhythmogenic right ventricular dysplasia (ARVD) with recurrent atrial flutter (AF) is reported. The patient had more frequent episodes of AF than of ventricular arrhythmias. Magnetic resonance imaging, echocardiography and right ventriculography revealed dilatation of the right ventricle and endomyocardial biopsy specimens from the right ventricle showed findings which were compatible with ARVD. The left ventricular specimen, however, also revealed a loss of myocytes and interstitial fibroelastic changes. The present case demonstrates an overlap of post-inflammatory or primary endomyocardial fibroelastic changes with ARVD.

Site-directed mutagenesis of the putative active site of endoglucanase K from Bacillus sp. KSM-330

The roles of one Glu and four Asp residues of endoglucanase K from Bacillus sp. KSM-330, which are conserved in all the endo-beta-glucanases in the family D, were analyzed by site-directed mutagenesis. The gene for endoglucanase K was mutated to replace Asp-154, Asp-191, Asp-193 or Asp-300 by Asn, or to replace Glu-130 by Gln in the encoded enzyme. Mutant and wild-type genes were separately expressed in Bacillus subtilis and the resultant enzymes were purified from the culture broth. All mutant enzymes exhibited the same mobility on SDS-polyacrylamide gel electrophoresis as the wild-type enzyme and gave similar circular dichroism spectra to that of the wild-type enzyme. Substitution of Glu-130, Asp-191, Asp-193 or Asp-300 significantly decreased the specific activity of the enzyme toward CM-cellulose. Kinetic analysis of the abilities of these mutant enzymes to liberate p-nitrophenol from p-nitrophenylcellotrioside revealed that all the mutant enzymes had very much lower kcat values than that of the wild-type enzyme, while the Km values of these mutant enzymes were almost the same as that of the wild-type enzyme. Of these Glu and Asp residues, Glu-130 and Asp-191 seem to be most likely to be catalytic residues because substitutions of these residues resulted in the lowest kcat values of the mutant enzymes.

Renal hypouricemia: incomplete combined defect

A 20-year-old man with hypouricemia with markedly increased renal uric acid clearance is described. He also exhibited idiopathic hypercalciuria and lipoid nephrosis on hospital admission. Urate excretion was minimally suppressed by pyrazinamide and minimally increased after administration of probenecid, whereas it decreased after administration of benzbromarone. These results suggest that not only presecretory reabsorption, but also postsecretory reabsorption of urate was incompletely defective and indicate that the latter is more defective than the former. The relationship between hypouricemia and hypercalciuria or lipoid nephrosis in this case is not clear. However, since the hypouricemia persisted despite the remission of minimal change nephrotic syndrome, it appears that at least his nephrosis was incidental.

Nerve fibers immunoreactive for substance P and calcitonin gene-related peptide in the cervical spinal ventral roots of the mouse

We demonstrate the existence of nerve fibers possessing substance P (SP) and calcitonin gene-related peptide (CGRP) immunoreactivity in the mouse cervical ventral roots. The distribution of the SP and CGRP fibers was similar, but CGRP fibers were generally more numerous. Both types entered the ventral pia mater or formed hairpin loops, but they did not enter the spinal cord directly through these roots. SP and CGRP fibers in the ventral roots were thin and had many varicosities. We suggest that these SP and CGRP fibers are involved not only in a sensory mechanism, but also in other functions, via the release of SP and CGRP from varicosities in the ventral roots.

Effect of physical properties of direct bonding adhesives on bonding to etched enamel

Five types of light-cured direct bonding adhesives with different volumes of microfiller were prepared for study of the relationships between bond strength to enamel, resinous tag length, and flexural strength, and between viscosity and resinous tag length. The resinous tag length was measured with the combination of 2,4,6-trichlorophenoxy methacrylate as a tracer and electron-probe microanalyzer. Correlating resinous tag length versus viscosity or bond strength after 1-day immersion, and flexural strength with bond strength after 1-day and 30-day immersion resulted in high correlation coefficients. However, the bond strength after thermocycling did not correlate with resinous tag length or flexural strength.

Glucocorticoid-unresponsive fever in a patient with Weber-Christian disease

Weber-Christian disease, a disease of unknown aetiology, is characterised by relapsing febrile episodes and systemic panniculitis. Glucocorticoid therapy is often useful during acute phases of the disease. This report describes a patient in whom hyperpyrexia did not respond to high-dose glucocorticoid treatment, yet did respond to a non-steroidal anti-inflammatory drug (NSAID).