[Interleukin-2 stimulates the proliferation of cultured RC-4B/C pituitary adenoma cell line]

The aim of the present study was to investigate whether interleukin-2 (IL-2) is involved in the proliferation control of the cultured RC-4B/C cell, which is a derived pituitary adenoma cell line of the rat. The level of cell proliferation was estimated by assessing (3)H-thymidine ((3)H-TdR) incorporation rate. IL-2 (10 1000 U/ml) significantly stimulated (3)H-TdR incorporation into the cell line in a dose-dependent manner. Specific PTK inhibitor tyrphostin (1 micromol/L) suppressed RC-4B/C cell proliferation and blocked the effect of IL-2 on RC-4B/C cells. After the PKA signaling pathway was inhibited by specific PKA inhibitor H-9 (1 micromol/L), the proliferation rate of RC-4B/C cells increased significantly. H-9 also enhanced the stimulation of IL-2 on RC-4B/C cell growth. Anti-estrogen tamoxifen (1 micromol/L) had no significant effect on the action of IL-2 on the proliferation of RC-4B/C cells. In conclusion, it is suggested that IL-2 modulates the proliferation of the cultured RC-4B/C pituitary adenoma cell line, and the action is closely related with the PTK and PKA signaling pathway.

Human herpesvirus 6 infection inhibits specific lymphocyte proliferation responses and is related to lymphocytopenia after allogeneic stem cell transplantation

Human herpesvirus 6 (HHV-6) infection and the HHV-6-specific lymphocyte proliferation response were studied longitudinally in 24 patients in the first 3 months after allogeneic stem cell transplantation (allo-SCT). HHV-6 DNAemia was analyzed by a nested PCR method, and the HHV-6-specific lymphocyte proliferation responses were evaluated with a standard lymphocyte proliferation assay. All patients who responded to HHV-6 GS (variant A) antigen also responded to HHV-6 Z29 (variant B) antigen, and a response to HHV-6 Z29 antigen was detected more often than to HHV-6 GS antigen after allo-SCT (P = 0.048). HHV-6 DNA was detected in more patients after than before transplantation (P = 0.01) and in more patients with acute GVHD grades II-IV than those without (P = 0.009). An HHV-6-specific proliferative response was more often detected in patients without, than in those with persistent HHV-6 infection (three consecutively positive PBL samples; P < 0.001). Patients with persistent HHV-6 infection had lower lymphocyte counts from the 8th week after transplantation than those without (P = 0.03). No HHV-6-specific proliferation responses were detected in the three patients who developed HHV-6 disease. HHV-6 infection was associated with persistent lymphocytopenia and might thereby inhibit immune function.

Reactivation of human herpesvirus 6 during pregnancy

Reactivation of human herpesvirus 6 (HHV-6) and cytomegalovirus (CMV) during pregnancy and transmission of the viruses to the fetus were investigated by polymerase chain reaction (PCR) and serology. In all, 104 blood samples were obtained 3 times during pregnancy and once at delivery. In another 107 women, samples were obtained only at delivery. Cord blood samples were obtained from both groups of women. HHV-6 DNA was detected in 41%-44% of the samples during months 3-8 of pregnancy, in 25% at delivery, and in 24% of age-matched controls. HHV-6 DNA was found in 1.0% of the cord blood samples. CMV DNA was detected in 1.7% of leukocytes from 104 pregnant women but in no cord blood sample. IgG antibodies to HHV-6 were found in 96% and CMV IgG in 62.5% of the women. HHV-6 IgG titers were significantly higher in HHV-6 PCR-positive women. Thus, HHV-6 reactivation seems common during pregnancy, and transfer of HHV-6 to the fetus may occur in approximately 1% of pregnancies.

Similar humoral and cellular immunological reactivities to human herpesvirus 6 in patients with multiple sclerosis and controls

Several studies have suggested an association between human herpesvirus 6 (HHV-6) and multiple sclerosis (MS). We have previously studied intrathecal production of antibody to lymphotropic herpesviruses in MS patients and the presence of human herpesvirus 1 to 7 DNAs in cerebrospinal fluid (CSF). In the present study anti-HHV-6 immunoglobulin M (IgM) in serum and anti-HHV-6 IgG subclasses in serum and CSF were examined and the lymphoproliferative response to HHV-6 was analyzed. The PCR examination was refined by purifying DNA from CSF and retesting the samples for HHV-6 DNA. There were no statistically significant differences between the groups concerning IgM positivity, distribution of IgG subclasses, or lymphoproliferative response to HHV-6. The purification of DNA increased the number of PCR-positive samples from 0 of 71 to 4 of 68. The study does not give additional support to the possibility that HHV-6 is a common cause of MS, but a role for the virus in a subset of patients cannot be excluded.

Human herpesvirus 6 DNA in cerebrospinal fluid specimens from allogeneic bone marrow transplant patients: does it have clinical significance?

Cerebrospinal fluid (CSF) specimens from 22 allogeneic bone marrow transplant patients with central nervous system (CNS) symptoms (cases) and 107 patients who were immunocompromised but did not have CNS symptoms (controls) were assayed for human herpesvirus 6 (HHV-6) DNA. HHV-6 DNA was detected in CSF specimens from five (23%) of 22 cases and in CSF specimens from one (0.9%) of 107 controls (P < .001, Fisher's exact test). In addition, none of the five cases with HHV-6 DNA detected in CSF samples had any other identified cause of their CNS symptoms, and none of the other 11 cases with known causes for their CNS diseases had HHV-6 DNA detected in CSF samples (P = .03, Fisher's exact test). In three cases, HHV-6 variant B was identified, and the HHV-6 variant could not be defined in the other two cases. Prophylaxis with acyclovir did not prevent the occurrence of HHV-6-associated CNS disease after allogeneic bone marrow transplantation. Four cases' conditions were improved or they were cured after treatment with either ganciclovir or foscarnet, and one case died of CNS disease despite foscarnet treatment.

Lymphoproliferative responses to human herpesvirus-6 variant A and variant B in healthy adults

Human herpesvirus-6 (HHV-6) isolates can be classified into variants A and B, and over 95% of people older than 2 years of age are seropositive for either or both variants. However, the prevalence of the two HHV-6 variants is still not defined since the serological methods used at present cannot discriminate one variant from the other. Lymphoproliferative responses to glycine extracted cellular antigens from human herpes-virus-6 (HHV-6) GS strain (variant A)- and Z 29 strain (variant B)-infected T-lymphoid cell lines were examined in healthy Swedish and Japanese adults. Nine of 36 (25%) persons had responses to the GS antigen, while 21/36 (58%) had responses to the Z 29 antigen (P=0.008). Individuals with low anti-HHV-6 IgG titers (< or = 320) were more likely to respond to the Z 29 antigen than to the GS antigen (P=0.006), while there was no difference in those with high anti-HHV-6 IgG titers (> or =1280). Three of 7 Japanese adults had lymphoproliferative responses to the GS antigen compared with 6/29 Swedes (not significant), and 7/7 Japanese had lymphoproliferative responses to the Z 29 antigen compared with 14/29 Swedes (P=0.03). Lymphoproliferative responses were neither related with the presence of HHV-6 DNA nor related with the presence of HHV-7 DNA in peripheral blood cells. These results suggest a higher prevalence of HHV-6 variant B than variant A in both Swedes and Japanese adults, and possibly a difference in either the HHV-6 virus strains and/or the nature of immune response of Swede and Japanese.

Cytomegalovirus DNA can be detected in peripheral blood mononuclear cells from all seropositive and most seronegative healthy blood donors over time

BACKGROUND

A poor correlation between cytomegalovirus (CMV) seroreactivity and the risk of CMV transmission prompted an investigation of the presence of CMV DNA in peripheral blood mononuclear cells (PBMNCs) from seropositive and seronegative blood donors. Because latent CMV exists in monocytes, monocyte-enriched cells were analyzed separately.

STUDY DESIGN AND METHODS

Samples from 270 blood donors were tested with a sensitive polymerase chain reaction (PCR) test that detects two CMV genes, and the results were correlated to CMV serology. Cross-reactivity with other herpesvirus genes was not recorded.

RESULTS

PCR testing demonstrated that 71 percent of seropositive donors harbor CMV in PBMNCs. Thus, not all seropositive donors were CMV DNA positive when individual samples were tested. Tests repeated over a period of time showed that all seropositive individuals were positive. Increased sensitivity was obtained with enriched monocytes. Among seronegative donors, 55 percent harbored CMV DNA in monocyte-enriched PBMNCs, while 14 percent had CMV DNA in PBMNCs.

CONCLUSION

All seropositive donors harbored latently infected PBMNCs, as demonstrated by the testing of samples collected over time. In addition, a substantial proportion of seronegative individuals are CMV carriers and might transfer infection. The findings concur with clinical evidence of CMV transmission by blood components from seronegative individuals and with in vitro reactivation of CMV in PBMNCs from seronegative donors.

[The different responses to anoxia in cultured CA1 and DG neurons from newborn rats]

Tissue culture from hippocampal CA1 or dentate gyrus (DG) region was established on the basis of previous neuronal culture technique. The viability, intracellular calcium concentration and brain-derived neurotrophic factor (BDNF) mRNA expression of the two kinds of neurons after anoxia were observed in the counting in the confocal microscopic field and in situ hybridization. It is found that DG neurons are not only more resistant to anoxia, but also have a stronger ability to keep calcium homeostasis and to express BDNF mRNA than CA1 neurons.

[Effect of adenosine on intracellular free calcium in cultured rat hippocampal CA1 neurons during anoxia]

Intracellular free Ca2+ concentration ([Ca2+]i) was measured by laser scanning confocal microscope, using Ca2+ indicator Fluo-3 in cultured hippocampal CA1 neurons isolated from newborn rat. The results showed that acute anoxia induced a rapid increase of [Ca2+]i in hippocampal CA1 neurons, and this increase could be attenuated by 100 mumol/L adenosine significantly. This effect of adenosine could be suppressed by adenosine A1 receptor antagonist CPT or potassium channel blockers, 4-AP and glipizide. These results suggest that adenosine activates 4-AP- or ATP-sensitive potassium channels through A1 receptors, and consequently inhibits the [Ca2+]i elevation in hippocampal neurons during anoxia.

Lymphotropic herpesviruses in allogeneic bone marrow transplantation

Human herpesvirus-6 (HHV-6), human herpesvirus-7 (HHV-7), Epstein-Barr virus (EBV), and human cytomegalovirus (CMV) DNA were repeatedly assayed in peripheral blood leukocytes from 37 allogeneic bone marrow transplant (BMT) patients by polymerase chain reaction. Before BMT, HHV-6 DNA was detected in 8 (22%) patients. HHV-7, EBV, and CMV DNA were detected in 21 (57%), 10 (27%), and 1 (3%) patient, respectively. After BMT, HHV-6 DNA was detected in 26 (70%), HHV-7 in 21 (57%), EBV in 28 (76%), and CMV in 21 (57%) patients. Thirty-two (87%) patients were positive with more than one virus. HHV-6, HHV-7, and EBV DNA were found earlier than CMV DNA in most patients after BMT. The proportions of HHV-6-positive samples during the first 3 months after BMT were higher in the patients with either delayed granulocyte engraftment (P = .04, Fisher's exact test) or delayed platelet engraftment (P = .001, Fisher's exact test). The HHV-6 DNA in samples from the patients with delayed engraftment was confirmed to be variant B. The detection of any lymphotropic herpesvirus was not related to the development of acute graft-versus-host disease (aGVHD). High-dose acyclovir (ACV) prophylaxis significantly (P < .01) reduced the proportion of HHV-6-positive samples and tended to lower HHV-6 DNA levels (P = .06). Our data indicate that HHV-6 variant B can inhibit marrow engraftment and that high-dose ACV may be beneficial to engraftment after BMT by preventing HHV-6 reactivation. No relation between the proportions of HHV-7-, EBV-, and CMV-positive samples in the first 3 months and engraftment or aGVHD was found.

[Involvement of the nerve fiber elements in the anterior pituitary in the regulation of ACTH secretion]

While peptidergic nerve fibers have been immunoreactively identified in the adenohypophysis of mammals, the function of these fibers in the regulation of hormone secretion remain unknown. The present work was undertaken to investigate possible modulating effects of these fibers on the secretion of ACTH in the anterior pituitary. Electrical field stimulation (EFS) was applied to excite the nerve terminals in anterior pituitary quarters of male rats under static incubation, and the ACTH level was determined by radioimmunoassay. It was found that the ACTH release from the anterior pituitary was significantly enhanced by EFS (30 mA, 0.5 ms and 10 Hz), which could be significantly decreased by adding TTX or veratridine into the incubation medium. However, TTX failed to inhibit AVP-induced ACTH secretion. Since the dispersed cultured anterior pituitary cells did not respond to the same EFS, it was suggested that there might exist dual modulatory mechanisms on the anterior pituitary hormone secretion.

Diagnosis of pulmonary infections in immunocompromised patients by fiber-optic bronchoscopy with bronchoalveolar lavage and serology

Fiber-optic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) were performed on 67 occasions in 57 immunocompromised patients with symptoms consistent with pulmonary infection. Diagnosis was achieved more often in renal transplant patients than in patients with hematological malignancies (85% versus 28%). Culture (bacteria, virus, fungi), staining and microscopy (bacteria, fungi, Pneumocystis carinii (PC)) and antigen detection by indirect immunofluorescence (cytomegalovirus (CMV), respiratory viruses, PC, Legionella) were used for diagnosis. On 20 occasions transbronchial biopsies with histopathologic examination were performed. In addition, serology comprising the herpes group (HHV-6) and respiratory viruses was done. A microbial diagnosis was obtained on 45% of occasions. The most common pathogens found were CMV (31%) and PC (25%). On 22 (33%) occasions a rapid diagnosis of 1 or more microbial agents was obtained within 24 h by conventional staining or indirect immunofluorescence. The clinical relevance of findings of CMV, HHV-6, and Epstein-Barr virus in BAL by polymerase chain detection on 18, 6 and 3 occasions is discussed. On 4 occasions pathogenic bacteria were found. It was not possible to relate findings of coagulase-negative staphylococci, alpha-streptococci and Candida albicans to the pulmonary infection.

Effect of ginsenosides against anoxic damage of hippocampal neurons in culture

AIM

To study the protective effect of ginsenosides (Gin) against anoxic injury in brain cells.

METHODS

On d 12 after plating of the hippocampal cells from newborn rat, the cultures were exposed to anoxic atmosphere (95% N2 + 5% CO2) for 4-24 h. The cellular morphology, survival rate, and effluxes of lactate dehydrogenase (LDH) and K+ from cells were observed.

RESULTS

After 24-h anoxia, the survival rate of cells was decreased from 92% +/- 4% before anoxia to 1.0% +/- 2.0%; the effluxes of LDH and K+ were increased from 2.3 +/- 0.6 U L-1 and 5.56 +/- 0.16 mmol L-1 before anoxia to 36 +/- 5 U L-1 and 8.5 +/- 0.7 mmol L-1, respectively. In the Gin group exposed anoxia for 24 h, the survival rate of cells was 4% +/- 4%; the effluxes of LDH and K+ were 30 +/- 3 U L-1 and 7.9 +/- 0.8 mmol L-1, respectively. All these changes were lower in Gin group than those of control.

CONCLUSION

Under anoxia the cultured hippocampal neurons were seriously damaged, which may be protected by Gin.

[Effects of cytokines on hippocampus in central nervous system]

Cytokines consist of a group of polypeptides, whose main functions are considered to be mediating the non-specific immune reaction and promoting differentiation, proliferation and growth of white blood cells. But according to recent studies, these cytokines such as interleukin-1 (IL-1), interleukin-2 (IL-2) and interleukin-6 (IL-6) and their receptors are also found in the central nervous system (CNS) and may play a role in modulating the physiological functions of neuronal and glial cells in CNS. In review, we summarize the representative studies concerning mainly the interleukins' effects on the hippocampus.

[Protective effect of calcitonin gene-related peptide on synaptic function in hippocampal slice during hypoxia]

Rat hippocampal slices placed in two compartments of a dual chamber were immersed in the superfusing artificial cerebrospinal fluid (ACSF) with 95% O2 + 5% CO2. The population spike (PS) and presynaptic fiber volley (PV) were recorded in CA1 pyramidal cells by stimulating Schaffer collateral pathways. Following hypoxia produced by replacing O2 with N2, the PS became gradually diminished and abolished, and in parts of the slices hypoxic injury spikes (HIP) could be observed. When 4 nmol/L beta-calcitonin gene-related peptide (beta-CGRP) -containing ACSF was superfused to the slice before and during hypoxia, the time at which PS began to decrease and got in complete abolishment were both postponed, and HIP were delayed or disappeared. After reoxygenation the recovery rate of PS was obviously higher in slices treated with CGRP than the control slices and the protective effect of CGRP was dose-dependent. In addition, superfusion of CGRP after hypoxia also increased the recovery of PS. These results indicate that (1) the time for the appearance of attenuation and disappearance of PS are varied according to the degree of hypoxia; (2) CGRP has a neuronal protective action against hypoxia.

[Effects of interleukin-1 and interleukin-2 on electrophysiological characteristics of rat hippocampal neurons in culture]

The effects of recombinant human interleukin-1 beta (rhIL-1 beta) and interleukin-2 (rhIL-2) on the cultured rat hippocampal neurons were investigated with intracellular recording and extracellular micropressure ejection techniques. Experimental results showed that all of the neurons tested with rhIL-1 beta (100 U/ml) exhibited a 4.20 +/- 1.86 mV membrane hyperpolarization. 50% of the neurons treated with rhIL-2 (100 U/ml) showed a depolarization of 11.12 +/- 3.71 mV accompanied by bursting activity, while in a still higher concentration (1,000 U/ml) a 3.25 +/- 0.63 mV hyperpolarization was observed. All the above effects of rhIL-1 beta and rhIL-2 on the hippocampal neurons were completely reversible. The membrane resistance of the neurons was not significantly affected by these cytokines. These results suggest that the effects of cytokines IL-1 and IL-2 on the excitability of hippocampal neurons may be a way by which the immune system exerts a regulatory action on hippocampal function.

[Effects of electrical lesioning of hippocampal CA3 region and anterior commissura hippocampi fornix on plasma insulin level and islet cells in the rat]

Bilateral electrical lesioning of the hippocampal CA3 region (HCA3-EL) or anterior commissura hippocampi (ACHF-EL) caused marked elevations in plasma basal levels of insulin. 2 weeks later, fasting blood glucose levels were also augmented with decreased glucose tolerance. In contrast, the secretory response of pancreatic B cells to glucose stimulation was markedly enhanced. Following intravenous glucose tolerance test (IVGTT), the relative amounts of glucagon-like and insulin-like immunoreactants were reduced in the pancreatic islets of both HCA3-EL and ACHF-EL rats in comparison with the controls. In the HCA3-EL group, the relative amounts of somatostatin-like immunoreactants and gross numbers of such immunostained cells in islets were also decreased as compared with the control. No difference was seen in pancreatic-polypeptide-like immunoreactivities as assessed by immunohistochemistry plus microphotometry method. The above results suggest strongly that HCA3 and ACHF exert a tonic inhibitory action on the insulin secretion in the rat.

Electrophysiologic follow-up in dogs receiving intracoronary ethyl alcohol injection

96% ethyl alcohol was injected into a diagonal branch of the left anterior descending coronary artery of 10 out of 12 anesthetized dogs, and saline solution was injected in the remaining 2. After chest closure, the dogs were subjected to ambulatory monitoring (H) during days 1, 2, 3 and 7. The electrophysiologic study (EPS) and signal-averaged electrocardiography. (SA-ECG) were performed before the injection and again at day 7 after injection. H failed in one dog which died of ventricular fibrillation. In the other 9 dogs that received alcohol injection, H showed frequent ventricular premature and ventricular tachycardia (VT) after injection; six of the 9 dogs sustained VT, which was not inducible by EPS. VT was not found in 2 control dogs receiving saline solution injection. The SA-ECG showed no ventricular late potentials in dogs receiving alcohol injection. Post-ablation ventricular arrhythmia (including VT) occurred after intracoronary ethyl alcohol injection in all dogs. Arrhythmogenicity markedly declined during the first 3 days and almost completely disappeared on day 7 after ablation. There was no evidence in favor of reentry as the mechanism of these arrhythmias. Enhanced automaticity was considered as the mechanism for ventricular arrhythmia.

Detection of human cytomegalovirus antigen and DNA in lymph nodes and peripheral blood mononuclear cells of patients with angioimmunoblastic lymphadenopathy with dysproteinemia

The cause of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) remains unknown. It is characterized by acute onset, severe constitutional symptoms, cervical or generalized lymphadenopathy, lymphopenia, and polyclonal hypergammaglobulinemia, all of which are highly suggestive of a viral origin. Using immunohistochemical methods, employing murine monoclonal antibody as the primary antibody, we detected human cytomegalovirus antigen in the lymph nodes of eight of 11 patients with AILD. Cytomegalovirus DNA was also detected in the peripheral blood mononuclear cells by DNA dot hybridization in all five of the patients with AILD who were tested using this technique. None of the lymph nodes from the 11 patients stained positive for the rubella virus antigen. Based on the above evidence and the similarity of the immunologic abnormalities found in both AILD and cytomegalovirus infection, the possible role of cytomegalovirus as one of the causative agents for AILD is proposed.

Transcoronary chemical ablation of ventricular tachycardia

Transcoronary chemical ablation of ventricular tachycardia was recently performed in one patient with refractory ventricular tachycardia in our hospital. The procedure was successful. The arrhythmia was cured and no recurrence occurred in a 24-month period. The clinical application and mechanism of transcoronary chemical ablation were discussed.

Relation between acute ventricular arrhythmias, ventricular late potentials and mortality in acute myocardial infarction

The relation between ventricular late potentials and the occurrence of acute (in-hospital) and hyperacute (before hospital admission) ventricular tachycardia or fibrillation was studied in 281 consecutive patients with uninterrupted acute myocardial infarction. The prevalence of late potentials was significantly higher in patients with than without ventricular tachycardia/fibrillation (65 vs 22%; p less than 0.01). These relations persisted among patients with left bundle branch block, although a different definition was used for identifying late potentials in these patients. Multivariate analysis showed that presence of late potentials and peak creatine kinase enzyme level were the only 2 independent variables associated with early ventricular tachycardia/fibrillation. Total in-hospital mortality, as well as in-hospital cardiac mortality, was significantly higher among patients with than without acute ventricular tachycardia/fibrillation. However, at 1 year, mortality rates did not differ between the 2 groups. The following conclusions were drawn from this study: (1) Late potentials are closely related to ventricular tachycardia/fibrillation in hyperacute and acute phases of infarction. (2) Presence of left bundle branch block does not mitigate against the finding of late potentials in these patients. (3) Early ventricular tachycardia/fibrillation in acute infarction is related to large infarctions and to a high in-hospital mortality rate.

Transcoronary ethanol ablation of experimental ventricular tachycardia after epicardial ice mapping and localizing

Thirty-seven reproducible ventricular tachycardias (VTs) were induced in 19 dogs after the onset of myocardial infarction. The site of origin of VT was localized in 19 (59%) of 32 VTs by ice epicardial mapping. After 0.3-1.2 ml of 95% ethanol was injected into a small coronary artery supplying the arrhythmogenic area, VT was no longer inducible in 10 of 14 dogs. Intramyocardial ethanol (1-3 ml) was injected into the site of origin of VT in 9 dogs including 4 with VTs reinduced after intracoronary ethanol. Six of these VTs were not reinduced. Thus, the total efficacy rate was 84%. In 7 dogs, after injection of 0.4-1.2 ml (mean 0.5 ml) of 95% ethanol into a small normal coronary artery, the extent of the changes in ECG, CK-MB and pathology was found to be related to the size of myocardial damage and to the dose of ethanol. The smaller the dose of ethanol was given and the more distal the branch of coronary artery into which the ethanol was injected, the smaller the myocardial damage was. The data demonstrated that intracoronary or intramyocardial injection of ethanol may ablate the experimental VT induced by programmed heart stimulation in dogs after myocardial infarction, indicating that this approach may be useful and meaningful in some selected instances. However, it is necessary to limit the myocardial damage as far as possible.

[An electrophysiological analysis of pathways from lateral septum to hippocampal CA1 area in rat]

Upon stimulating the lateral septal region, a population spike could be recorded in the stratum pyramidale of hippocampal CA1 together with a recordable EPSP in the apical dendrites (stratum radiatum). After destruction of hippocampal CA3, CA4 pyramidal cells by intraventricular microinjection of kainic acid, electrical stimulation of the lateral septum could no longer evoke EPSP in the apical dendrites. This experiment suggests that the neural connection of the lateral septo-CA1 apical dendrites is mediated by the collaterals of the ipsilateral CA3 pyramidal cells. But after the destruction of CA3, CA4, electric stimulation of lateral septum could still evoke EPSP in the basal dendrites (stratum oriends). The neural connection mediating the response of the lateral septo-CA1 basal dendrites was not reported before, but the neural pathway remains to be investigated.

Delayed-type hypersensitivity antigens detected in culture supernatants of Salmonella typhimurium

Protein antigens eliciting delayed type hypersensitivity (DTH) were analyzed and purified from the supernatants of protein-free cultures in which Salmonella typhimurium TV148 organisms had grown. DTH activity was measured by the footpad swelling test in mice immunized with living organisms of S. typhimurium TV148 or Escherichia coli K-12. DTH activity in the culture supernatant was specific to TV148-immunized mice. This activity was destroyed by pronase. DTH activity was unable to pass through an ultrafilter with an exclusion limit of 10 kD. After condensation of the supernatant and following centrifugation (100,000 g for 1 h), the DTH activities of the sediment and the supernatant were examined, and both showed DTH activity. Further analyses of DTH antigens in the supernatant by HPLC gel filtration separated the activity into three portions. The most active portion was further fractionated by hydroxyapatite HPLC, revealing the presence of two DTH antigens, with molecular weights of 65 and less than 10 kD. These results indicate that the culture supernatant of S. typhimurium TV148 organisms contains a variety of macromolecular protein DTH-eliciting antigens, and one of the antigens is 65 kD, which is dissociated partly by organic solvents into a low molecular weight (less than 10 kD) antigen.

[The relationship between tissue type plasminogen activator therapy and ventricular late potentials in acute myocardial infarction]

We studied the relationship between thrombolysis and late potentials (LP) in 137 patients with acute myocardial infarction (AMI). Among 37 patients treated with tissue-type plasminogen activator(t-PA treated group), LP were recorded in 2 patients (5%). In contrast, among 100 conventionally treated patients (control group), LP were seen in 26 (26%, P less than 0.01). When the two groups were matched with respect to age, sex, absence of prior infarction, LVEF, number of abnormal Q waves, ECG score and CAD score, the same incidence of LP was seen, i.e. 6% of the 34 t-PA treated patients had LP as compared with 24% of the 42 conventionally treated patients (P less than 0.05). Angiographic examination following t-PA infusion revealed that the incidence of LP was 0% and 40% in patients with patent and closed infarct-related coronary artery respectively. 1 year follow-up data showed that no deaths occurred in the t-PA treated group, while in the control group. 18 deaths were recorded and 8 of them were classified as sudden death. These observations suggest that patients with AMI treated early with thrombolysis have electrically more stable ventricles due to improvement of ischemia.

Cholinergic function in cultures of mouse spinal cord neurons

Cholinergic synapses formed in cultures of fetal mouse spinal cord (SC) and superior cervical ganglion (SCG) were studied using intracellular and extracellular stimulation and recording as well as immunohistochemical staining for choline acetyltransferase (ChAT). Dissociated SC neurons and SC explants exhibited cholinergic terminals on SCG and SC neurons as demonstrated by ChAT immunoreactivity. Intracellular recordings showed that cholinergic inputs to SCG neurons were relatively common and that these synaptic inputs were blocked by the nicotinic acetylcholine (ACh) receptor blocker, tubocurarine. A comparison of three preparations indicated that the incidence of cholinergic activity recorded in SCG neurons was significantly higher in co-cultures of SCG with spinal cord ventral horn (VH) neurons grown on a substrate of non-neuronal cells from cerebral cortex, than in co-cultures with VH alone or with SC and dorsal root ganglion cells. Consistency between cholinergic physiology and staining for ChAT-positive terminals on SCG neuronal somata was obtained in cultures of SC explants grown with dissociated SCG. Application of acetylcholine, muscarine, and/or vasoactive intestinal polypeptide (VIP) produced slow excitation of SC neurons. Fast excitatory cholinergic interactions between SC neurons were not observed. Excitatory synaptic interactions between SC neurons were augmented by ACh or muscarine, while inhibitory synaptic interactions were diminished. Both types of synaptic modulation probably were produced by a presynaptic mechanism. Acetylcholine or muscarine affected synaptic interactions between SC neurons in only one-third of the synaptic connections tested, suggesting that the incidence of presynaptically cholinoceptive SC neurons is low in dissociated cell cultures. The experimental results show that a culture system incorporating dissociated fetal mouse SC neurons or explants of SC with sympathetic ganglion neurons expresses both nicotinic and muscarinic cholinergic function.

Decreased incidence of ventricular late potentials after successful thrombolytic therapy for acute myocardial infarction

In some patients with acute myocardial infarction, low-amplitude potentials that prolong the QRS complex, termed "late potentials," can be recorded on a signal-averaged electrocardiogram. The presence of these late potentials is known to be associated with an increase in the risk of ventricular tachycardia and sudden death. Because patients with acute myocardial infarction who receive thrombolytic therapy have a reduced incidence of ventricular tachyarrhythmia and sudden death, we sought to determine whether such patients also have a decreased incidence of late potentials. We studied 106 patients less than 75 years of age who were admitted with a first myocardial infarction and in whom a signal-averaged electrocardiogram was recorded within 48 hours of admission. Within four hours of the onset of chest pain, tissue plasminogen activator (t-PA) was given to 44 patients, and 62 were treated conventionally. In the t-PA group, late potentials were recorded in 2 of 44 patients (5 percent), as compared with 14 of 62 (23 percent) in the conventionally treated group (P = 0.01). Furthermore, among the patients treated with t-PA, continued occlusion of the infarct-related artery was related to the presence of late potentials. In the t-PA group, late potentials were recorded within 24 hours of angiography in 2 of the 6 patients with an occluded infarct-related artery, as compared with none of the 38 patients with a patient infarct-related artery. Our data suggest that successful thrombolytic therapy is associated with a marked reduction in the incidence of late potentials on the signal-averaged electrocardiogram. Long-term follow-up will be required to determine whether this finding predicts a reduced incidence of subsequent ventricular tachyarrhythmia and sudden death.

Alterations of coronary vascular responses to noradrenaline, acetylcholine and isoprenaline during acute myocardial ischaemia in dogs

1. The reactivity of coronary arteries to noradrenaline (NA), acetylcholine (ACh) and isoprenaline (Iso) during acute myocardial ischaemia was studied in anaesthetized, open-chest dogs. 2. The left anterior descending coronary artery (LAD) was cannulated and perfused via an extracorporal circuit at constant flow. Ischaemia was produced by decreasing the perfusion blood flow of the LAD to 50% (moderate ischaemia) and 27% (severe ischemia) of normal. A dose of each agent which had no significant myocardial effects was chosen. Heart rate was held constant by ventricular pacing during ACh administration. 3. Under normal conditions, the infusion of NA, ACh and Iso into the LAD produced significant decreases in coronary vascular resistance (P less than 0.01). However, under either moderate or severe ischaemic conditions intracoronary NA resulted in a marked increase in coronary vascular resistance (P less than 0.01), which was completely blocked by phentolamine, an alpha-adrenoceptor blocker; intracoronary ACh and Iso did not have a significant effect on coronary vascular resistance (P greater than 0.05). 4. These results indicate that coronary arterial responsiveness to some intrinsic vasoactive substances, such as NA and ACh, is altered during acute myocardial ischaemia. This may be important in the pathophysiology of myocardial ischaemia.

[Content, location and action site of enkephalins in arterial walls]

Contents of L-enkephalin (L-ENK) and M-enkephalin (M-ENK) in arteries of rabbit were measured by radioimmunoassay. Mean values of L-ENK and M-ENK (pg/mg of wet tissue) were 38.99 +/- 17.29 and 134.67 +/- 8.11 in the rabbit ear artery; 31.10 +/- 7.76 and 93.60 +/- 18.22 in the renal artery; 25.70 +/- 13.60 and 88.43 +/- 18.16 in the mesenteric artery, respectively. L-ENK in these arteries decreased significantly (P less than 0.001) after chemicosympathectomy by injection of 6-OHDA; ENK in the ear artery were reduced significantly (P less than 0.001) following the excision of the superior cervical ganglion or electrical-field stimulation, but not changed after injection of reserpine. Content of NE in the artery strip bath medium was measured by fluorimetric assay. NE in the medium was decreased significantly after administration of L-ENK or M-ENK. The results suggest that enkephalins may exist in the sympathetic nerve terminals innervating arterial walls and may be released by electrical-field stimulation. Enkephalins inhibit the contracting activity of artery strips probably by decreasing the release of NE from sympathetic nerve endings.

[Effect of cardiac sympathetic nerves on changes of TXB2 and 6-keto-PGF1 alpha in venous blood of ischemic myocardium]

Experiments were performed on 54 anesthetized, open-chest dogs to observe the effect of cardiac sympathetic nerves and alpha- and beta-adrenoceptor blockades on changes of platelet function during the early phase of myocardial ischemia. It was shown that contents of TXB2 and 6-keto-PGF1 alpha after coronary occlusion were markedly increased, and the platelet count was reduced in the coronary venous blood of ischemic myocardium. It was found that the changes in parameters of platelet function after coronary occlusion were significantly relieved by topical application of lignocaine-soaked gauze pads to the ischemic area of the heart or by bilateral stellectomy for blocking impulse of afferent and efferent of cardiac sympathetic nerves, compared with changes in parameters of control group, P less than 0.01. On the other hand, changes in parameters of the control group could be restored by intravenous infusion of noradrenaline to dogs which bilateral stellectomy was performed on, but not by infusion of normal saline. Different effects of alpha- and beta-adrenoceptor blockades on the changes in aforementioned parameters were found. The changing degrees in elevation of TXB2 and 6-keto-PGF1 alpha and in decrease of platelet count were significantly relieved by intravenous infusion of yohimbine (an alpha 2-blocker), phentolamine (a nonselective alpha-blocker), and propranolol (a beta-blocker), but not by infusion of prazosin (an alpha 1-blocker). Results were compared with the control group, P less than 0.01. These results suggest that cardiac sympathetic nerves play an important role for the changes of platelet function during the early phase of myocardial ischemia and that, yohimbine and phentolamine may exert an improving effect by blocking alpha 2-receptors on the platelet membrane, and propranolol may directly contribute to stabilization of the platelet membrane.

Intra-hisian block associated with unusual etiologies

One hundred and sixty-nine patients underwent electrophysiologic study for atrioventricular block. Forty-five (27%) had intra-Hisian block. Four of these 45 patients had unusual etiologies: rheumatoid arthritis, cysticercosis cellulosae, Behcet's disease, and Takayasu aorto-arteritis. Their clinical and electrophysiologic features are described in detail.