Monocyte-derived cultured dendritic cells are susceptible to human immunodeficiency virus infection and transmit virus to resting T cells in the process of nominal antigen presentation

The susceptibility of monocyte-derived cultured dendritic cells (DCs) to human immunodeficiency virus (HIV) infection and their role in viral transmission in the immune response were studied in detail. We observed that highly purified cultured DCs were infected with the T-tropic Lai strain of HIV type 1 (HIV-1Lai) via the CD4 receptor, and this was followed by formation of the complete provirus as detected by PCR. HIV mRNAs were transcribed at only low levels, and virus production was undectable; however, the addition of the purified protein derivative antigen of tuberculin and of autologous resting T cells to HIV-1Lai-infected DCs but not to HIV-1Lai-infected macrophages led to massive HIV transmission and production. These data suggest that the interaction of infected DCs with T cells during the normal immune response could play an important role in the activation and expansion of HIV.

Chemoprevention by dietary dehydroepiandrosterone against promotion/progression phase of radiation-induced mammary tumorigenesis in rats

When pregnant rats received whole body irradiations with 260 cGy gamma-ray at day 20 of pregnancy, and were then implanted with a diethylstilbestrol (DES) pellet for an experimental period of 1 year under feeding of a control diet, a high incidence (96.2%) of mammary tumors was observed. Administration of dietary 0.6% dehydroepiandrosterone (DHEA) together with DES implantation significantly decreased the incidence (35.0%) of mammary tumors. The first appearance of palpable tumors in the DHEA-fed group was 4.5 months later than that in the control group. For clarification of the mechanism of the chemopreventive action, we measured hormone levels in the serum of DHEA-fed rats. In the DHEA diet rats, the concentration of estradiol-17 beta exceeded, by approximately 6-fold, that in the control rats, while the levels of progesterone and prolactin were decreased by 30 and 45%, respectively. Interestingly, DHEA feeding prevented DES-induced hypertrophy of pituitary glands and DES-induced high level of prolactin in pituitary glands detected by immunohistochemical studies, but stimulated the development of mammary glands more than that in control rats treated with DES alone. These findings suggest that DHEA has a potent preventive activity against the promotion/progression phase of radiation-induced mammary tumorigenesis. The mechanism of chemoprevention by change of endocrinological environment is discussed.

[Effect of dosing schedule on efficacy of corticosteroid inhalation in chronic asthma]

A randomized study was conducted for 4 weeks to evaluate the effect of twice daily inhalation of beclomethasone dipropionate (BDP) inhalation (group A) as compared to four times a day inhalation (group B) in chronic asthma. Patients were randomly allocated to receive BDP at a dosage of eight puffs twice daily (800 micrograms/day, group A) or four puffs four times daily (800 micrograms/day, group B). Forty four patients entered the study but eleven were excluded because of their insufficient records or unfitness to eligibility criteria. There was no significant difference in patients' characteristics such as types, and severity of diseases between the two groups. Daily keeping of symptom scores, twice daily measurement of morning and night peak expiratory flow (PEF) and checking of the drug consumption were performed throughout the study. There was no significant difference in the mean %PEF either at 2 and 4 weeks at the study between the two groups. Symptom scores, asthmatic scores, bronchial hyperresponsiveness, pulmonary function tests (FVC, FEV1, FEV1%) and serum cortisol levels also showed no significant difference between the two groups. These results indicate that twice daily inhalation of BDP (800 micrograms/day) for four weeks caused the same effects on the patients with chronic bronchial asthma as 4 times daily inhalation did. Therefore, twice daily inhalation therapy with BDP is recommended for chronic bronchial asthma patients.

[Efficacy of video thoracoscopic lung biopsy in diffuse lung diseases: comparison with open lung biopsy]

The efficacy and safety of video thoracoscopic lung biopsy (VTLB) and of open lung biopsy (OLB) were compared in patients with diffuse lung diseases. Thirty-three patients who had undergone VTLB were retrospectively studied and compared with 67 patients who had undergone OLB. There were no significant differences in age (52.8 +/- 10.9 vs 53.4 +/- 10.3), in the number of biopsies per patient (2.6 +/- 0.6 vs 2.7 +/- 0.6), or in the rate of diagnosis (94% vs 93%) between the two groups. However, the rate of diagnosis was low when the number of VTLB or OLB performed per patient was low. The patients undergoing VTLB had significantly shorter operative times (VTLB, 100.2 +/- 27.2 min. vs OLB, 119.8 +/- 42.6 min; p < 0.01) and less blood loss (VTLB, 4.7 +/- 14.6 ml vs OLB, 65.7 +/- 77.0 ml; p < 0.001). Complications occurred in 3 of the 33 who underwent VTLB, and in 18 of the 67 who underwent OLB. These results indicate that VTLB is an effective and safe alternative in the diagnosis of diffuse lung diseases.

Apoptotic cell death triggered by nitric oxide in pancreatic beta-cells

Nitric oxide (NO) is believed to be an effector molecule that mediates interleukin (IL)-1 beta-induced destruction and dysfunction of pancreatic beta-cells. We have demonstrated that both exogenous NO and NO generated endogenously by IL-1 beta brought about apoptosis of isolated rat pancreatic islet cells as well as pancreatic beta-cell tumor-derived cell line HIT. This apoptosis was characterized by cleavage of DNA into nucleosomal fragments of 180-200 bp and morphologically by nuclear shrinkage, chromatic condensation, and apoptotic body formation. The IL-1 beta-induced internucleosomal DNA cleavage occurred in a time- and dose-dependent manner. Actinomycin D, cycloheximide, and nitric oxide synthase inhibitors inhibited the DNA cleavage, which was correlated with the amount of NO produced, indicating that NO produced by HIT cells themselves could mediate the apoptosis. Furthermore, in the presence of tumor necrosis factor (TNF)-alpha, large amounts of NO were produced by IL-1 beta and DNA cleavage occurred more noticeably, although TNF-alpha alone did not generate NO. Streptozotocin (STZ), a diabetogenic reagent containing a nitroso moiety, also released NO and induced internucleosomal DNA cleavage in HIT cells. These results suggest that NO-induced internucleosomal DNA cleavage is an important initial step in the destruction and dysfunction of pancreatic beta-cells induced by inflammatory stimulation or treatment with STZ.

A novel integron-like element carrying the metallo-beta-lactamase gene blaIMP

A plasmid-mediated metallo-beta-lactamase gene was cloned from a carbapenem-resistant Serratia marcescens strain, AK9373. The metallo-beta-lactamase gene was identical to the blaIMP, and it was located in the space between an integrase-like gene and an aac(6')-Ib-like gene. The deduced amino acid sequence for the putative integrase gene showed considerable identity (60.9%) to that of the Escherichia coli integrase reported. Sequences similar to the GTTRRRY and an atypical 59-base element containing a 67-bp inverted repeat sequence, which were peculiar to the integrase-dependent recombination, were also conserved in the flanking regions of the blaIMP gene. These findings imply that the metallo-beta-lactamase gene in S. marcescens AK9373 is carried by a novel integron-like element that is mediated by a transferable large plasmid.

[A case of male infertility with a chromosomal abnormality of 45, X/46, X + mar]

A 28-year-old man visited our hospital with a complaint of male infertility. His development was normal with body size of 169.5 cm in height and muscular type. His beard and axillary and pubic hairs were male type. The penis and scrotum were also normal, but testes were small (8 ml, bilateral). Semen analysis revealed azoospermia. Serum luteinizing hormone (LH) and testosterone levels are within normal range but follicle stimulating hormone (FSH) was moderately elevated. Testicular biopsy specimen showed severely hyalinized seminiferous tubuli, incarceration of basement membrane and hyperplasia of Leydig cells. Johnsen's score count was two. Chromosomal analysis revealed a mosaic type of 45, X/46, X + mar. We tried to confirm the existence of sex-determining region of the Y chromosome (SRY) by the DNA analysis. It was shown that SRY on genomic DNA fragment. This marker chromosome may be translocated to a fragment of the short arm of Y chromosome.

The Sauvé-Kapandji procedure for osteoarthritis of the distal radioulnar joint

The Sauvé-Kapandji procedure has been performed in 15 patients with primary and secondary osteoarthritis of the distal radioulnar joint. The average age of the patients was 45 years (range, 31-63 years). There were 12 men and 3 women. The follow-up period averaged 2 years and 11 months. Postoperative pain relief was good in all wrists. The preoperative range of motion of the wrist joint averaged 50 degrees extension and 44 degrees flexion. Forearm motion averaged 66 degrees pronation and 64 degrees supination. Postoperatively, the range of motion improved to 55 degrees extension and 51 degrees flexion at the wrist and forearm motion improved to 78 degrees pronation and 82 degrees supination. Although all wrists also showed an increased grip strength and improved range of motion over preoperative values, these did not have statistical significance. Postoperative x-ray evaluation showed an unstable proximal stump and radioulnar convergence in 12 wrists. Our clinical and x-ray film findings suggest that the Sauvé-Kapandji procedure is a satisfactory procedure for patients with osteoarthritis of the distal radioulnar joint.

Superoxide dismutase derivative reduces oxidative damage in skeletal muscle of rats during exhaustive exercise

A superoxide dismutase derivative (SM-SOD) that circulates and is bound to albumin with a half-life of 6 h was injected intraperitoneally into rats before exhaustive treadmill running to study its antioxidant scavenging capacity in the plasma and soleus and tibialis muscles. The exercise induced a marked increase in xanthine oxidase activity in plasma and an increase in thiobarbituric acid-reactive substances in the plasma as well as in the soleus and tibialis muscles of nonadministered rats immediately after the exercise. The immunoreactive content and activity of both SOD isoenzymes (Cu,Zn-SOD and Mn-SOD) of the nonadministered rats increased in the soleus and tibialis muscles immediately after running. SM-SOD treatment definitely attenuated the degree of the increase in thiobarbituric acid-reactive substances and xanthine oxidase in all samples examined immediately after exercise. Glutathione peroxidase activity significantly increased in the soleus muscle of nonadministered rats 1 day after running, whereas catalase activity remained unchanged throughout the experimental period. These results suggest that a single bout of exhaustive exercise induces oxidative stress in skeletal muscle of rats and that this oxidative stress can be attenuated by exogenous SM-SOD.

Coprevalence of bulimia with alcohol abuse and smoking among Japanese male and female high school students

Bulimia nervosa (bulimia) is often concomitant with alcohol and other substance abuse. To investigate the coprevalence of bulimia with alcohol abuse and smoking, we surveyed 2597 male and female Japanese high school students and obtained a group of bulimic students who fulfilled four of five DSM-III-R bulimia nervosa criteria and a control group who reported no binge-eating experience. Comparison of the groups showed significantly more alcohol abuse for both male and female bulimic students than for the non-bulimic control group. The male and female adolescents with symptoms of bulimia were similar in showing a high prevalence of alcohol abuse. The incidence of smoking was significantly higher among the bulimic females than among the female controls, but there was no significant difference between the male groups' smoking experiences.

The twitcher mouse: a model for Krabbe disease and for experimental therapies

The twitcher is a naturally-occurring mouse mutant caused by an abnormality in the gene coded for galactosylceramidase. It is therefore genetically equivalent to human globoid cell leukodystrophy (Krabbe disease). Affected mice develop clinical symptoms at the onset of the active myelination period and, if untreated, die by 35 +/- days. The pathology is very similar to that in human disease. Toxicity of galactosylsphingosine (psychosine) that accumulates abnormally in the nervous system is considered to be primarily responsible for the pathogenesis. Transplantation of bone marrow cells from normal donors is partially effective and triples the life span of affected mice to 100 +/- days with evidence of remyelination in the CNS. The mutation responsible for the twitcher mutant has recently been identified. It is expected that this model will be useful for basic studies on treatment of this group of genetic disorders affecting the brain through transgenic and/or gene therapy approaches.

Dispersion state of phospholipids and fluorescence production with peroxidation in organic solvents: investigated by time-resolved fluorescence technique

Fluorescent substances were found to be produced efficiently when phospholipids containing phosphatidylethanolamine (PE) and linoleic chains were autoxidized in non-polar solvents. By using these fluorescent substances as intrinsic probes, the dispersion state of phospholipids was investigated in various organic solvents. Fluorescence anisotropy decay measurements indicated that the aggregation size of phospholipids was much larger in hexane than in chloroform, methanol and tert-butyl alcohol. The average diameter of phospholipid aggregates in hexane was calculated to be 4-6 nm, which was dependent on the lipid composition. A consistent result was obtained when N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-1,2-dihexadecanoyl-sn-gly cer o-3- phosphoethanolamine (NBD-PE) was used as an extrinsic probe. Comparison of the fluorescence data with small-angle X-ray scattering (SAXS) data suggested that a reverse micellar structure of phospholipids formed in hexane. It was shown that phospholipid aggregation enhanced the extent of peroxidation as well as the production yield of fluorescent substances of phospholipid.

Antithrombotic effect of a humanized anti-GPIIb/IIIa monoclonal antibody, YM207, in a photochemically induced thrombosis model in monkeys

We investigated the antithrombotic effects of a F(ab')2 fragment of a humanized anti-platelet glycoprotein (GP) IIb/IIIa monoclonal antibody, YM207, in a platelet-rich thrombosis model. Thrombus was induced in a mesenteric venule of squirrel monkeys by irradiation with filtered light in combination with i.v. administration of a fluorescent dye (sodium fluorescein). Time to occlusive thrombus formation was significantly prolonged by i.v. bolus injection of 0.3 mg/kg of YM207. At doses of 1 mg/kg and 3 mg/kg, complete occlusion did not occur during 60 min of the observation. Platelet aggregation in platelet-rich plasma was inhibited by YM207 at doses 0.3 mg/kg or more. A good correlation was obtained between inhibition of platelet aggregation and the percentage of GPIIb/IIIa receptors blocked by YM207. Bleeding time was significantly prolonged at a dose of 3 mg/kg. Platelet counts showed no significant change. These results suggest that YM207 is effective in preventing platelet-rich thrombus formation without inducing the prolongation of bleeding time or a significant decrease in platelet count. YM207 may be a useful therapeutic agent for the treatment of thrombotic disorders.

Role of subunit-9 of mitochondrial ATP synthase in Batten disease

The role of subunit-9 of mitochondrial ATP synthase in Batten disease was defined by characterizing the expression of genes encoding this protein in human tissues. Two genetically distinct neuronal ceroid-lipofuscinoses (NCL) comprise Batten disease: the late-infantile (LINCL) and juvenile (JNCL) types. We tested cell lines and tissues from both types of patients, along with normal controls. Differences in expression between diseased and normal samples were found for both mRNA and protein. Antibody staining of subunit-9 protein was detected in LINCL and JNCL tissues, and in 6 LINCL and 4 of 5 JNCL fibroblast lines. No immunoreactivity was seen in fibroblasts from obligate carriers, normal controls, and 6 other storage disease controls, with the exception of faint staining in Niemann-Pick, type C cells. There was an appreciable difference in staining pattern in both tissue sections and fibroblasts between LINCL and JNCL. Three subunit-9 transcripts (Hum1, Hum2, and Hum3) were specifically detected in NCL and normal human tissue from heart, liver, brain, muscle, and pancreas. Transcriptional regulation of subunit-9 genes was found to be altered in Batten disease. Pseudogenes related to each of the subunit-9 genes were isolated. Sequence analysis of cDNAs spanning the protein-coding regions of the Hum1, Hum2, and Hum3 genes showed conclusively that the primary defect(s) causing NCL are not mutations in the protein-coding regions of the 3 known subunit-9 genes.

Molecular analysis of the acid sphingomyelinase deficiency in a family with an intermediate form of Niemann-Pick disease

A novel point mutation in the lysosomal acid sphingomyelinase gene has been identified in the recently reported Serbian family with a clinically and biochemically atypical intermediate form of Niemann-Pick disease. The mutation was a T1171-->G transversion resulting in substitution of glycine for normal tryptophan at amino acid residue 391. The coding sequence was otherwise normal. All of the five affected individuals were almost certainly homoallelic, and both of the two obligate heterozygotes studied also carried the same mutation. This mutation is therefore likely to be directly associated with the atypical phenotype of these patients. Expression in COS-1 cells suggested a higher residual activity than that in cultured fibroblasts. A recently developed high-affinity rabbit antihuman sphingomyelinase antibody allowed us to study for the first time the biosynthesis, processing, and targeting of a mutant sphingomyelinase by metabolic labeling of cultured fibroblasts. The mutant enzyme protein was normally synthesized, processed, and routed to the lysosome but was apparently unstable and degraded rapidly once it reached the lysosome. Together with the finding of the relatively high residual activity in COS-1 cells, we interpret our observations to mean that instability and rapid breakdown of the mature mutant enzyme protein, due to the mutation rather than direct inactivation of the catalytic activity, is the primary mechanism for the deficiency of sphingomyelinase activity in these patients. A high prevalence of this mutation in the Serbian population is likely, since the family pedigree indicates that members from four reportedly unrelated families must have contributed the same mutation.

Multinucleated giant cells undergoing apoptosis in experimental autoimmune myocarditis

This study used an experimentally induced myocarditis model in rats to demonstrate the formation and fate of multinucleated giant cells which are known to occur in different kinds of inflammatory lesions. Multinucleated giant cells were frequently recognized in the inflammatory foci, being intermingled with numerous ED1-positive inflammatory macrophages rich in phagosomes. The giant cells reacted with the ED1 antibody but not with ED2, and ultrastructurally resembled the inflammatory macrophages. Multinucleated giant cells possessing less than 5 nuclei in an ultrathin section were rich in phagosomes, whereas those with more nuclei contained numerous lipid droplets and only few phagosomes in their cytoplasm. Light microscopic observation of hematoxylin-eosin stained sections revealed that some multinucleated giant cells displayed variously sized dark bodies which likely corresponded to condensed and fragmented nuclear chromatin. Such multinucleated giant cells were positively stained with the TUNEL method. Under the electron microscope, all nuclei in one multinucleated giant cell showed an eccentric mass of homogeneously condensed chromatin. These observations suggest that multinucleated giant cells are formed by aggregation and also likely by fusion of inflammatory macrophages; gradually loosing the phagocytotic activity characteristic of the latter cells, they then die by apoptosis.

n-3 and n-6 fatty acid intake and serum phospholipid fatty acid composition in middle-aged women living in rural and urban areas in Okayama Prefecture

Dietary fatty acids and serum lipids were evaluated in 68 middle-aged women living in the northern, rural area of Okayama Prefecture, and were compared with the values obtained from 65 urban women from the southern part of this prefecture. A higher level in HDL cholesterol and a lower atherogenic index were observed in the rural women. The percent of energy intake as fat was lower (20.4 +/- 0.8% vs. 23.2 +/- 0.7%) and that of carbohydrate was greater in the rural group. Eicosapentaenoic (EPA, 0.41 +/- 0.04 g/day) and docosahexaenoic acid (DHA, 0.70 +/- 0.08 g/day) intakes were significantly higher in the rural subjects than in the urban group. Significantly higher DHA levels and n-3/n-6 fatty acid ratios in serum total phospholipids were found in rural women in their fifties and the sixties compared to urban women. Dietary linoleic acid (LA) amounts were positively correlated with LA (p < 0.05), and negatively with the EPA (p < 0.05) and DHA (p < 0.01) contents of serum total phospholipids. These results suggest that the traditional Japanese diet, containing little fat but enriched in complex carbohydrates and n-3 fatty acids of marine origin, may be related to the low atherogenic index in this rural area.

[Complete remission of prostate cancer after LH-RH agonist neoadjuvant therapy: a case report]

We report a case of prostate cancer showing a complete remission after LH-RH agonist neoadjuvant therapy. A 69-year-old man was referred to our department complaining of pain on urination and urge incontinence. The serum prostate specific antigen (PSA) level was 41.6 ng/ml. Needle biopsy specimens from both lobes revealed moderately differentiated adenocarcinoma. Chest X-ray, computed tomographic (CT) scan, and bone scintigraphy demonstrated neither distant metastasis nor local invasion. LH-RH agonist was administered on a monthly basis as neoadjuvant therapy. After 4 injections, pelvic lymph node dissection and radical prostatectomy were performed on January 11, 1993. Thorough examination did not reveal any cancer cells in the removed specimen. The patient was discharged 30 days after the operation and has shown no evidence of distant metastasis or local recurrence as long as 19 months later.

Modification of delayed-type hypersensitivity reactions by muramyldipeptide in guinea pigs

N-Acetylmuramyl-L-alanyl-D-isoglutamine (muramyldipeptide, MDP) modulated delayed-type hypersensitivity (DTH) reactions and induced severe inflammatory lesions in guinea pigs. The animals immunized with heat-killed Mycobacterium tuberculosis were challenged with the purified protein derivative (PPD) at the flanks and the corneas to prepare DTH reactions at 2 weeks after the immunization, thereafter 24 h the animals received subcutaneous injections of MDP at the flanks of the opposite side. At the skin with the DTH reaction, increase of swelling and redness accompanied with hemorrhage and necrosis were observed. As corneal reactions in the animals that had received MDP, increase of cornea thickness, opaque and grayish-white and the projection of eyes accompanied with severe iritis were observed. Modification of the skin reaction occurred from 2 h after the MDP injection, rapidly increased to the maximum level around 10 h, maintained the level until 24 h, then slowly decreased. The polymorphonuclear leukocyte infiltration was observed from 15 min after the MDP injection, and tumour necrosis factor alpha, interleukin (IL)-1, and IL-6 levels in the serum and skin lesions increased after the MDP injection. Synthetic muramyltripeptide (N-acetylmuramyl-L-alanyl-D-isoglutaminyl-L-lysine) also provoked definite skin reactions, while the larger peptidoglycan fragments and various inflammatory agents including cytokines so far examined were inactive in this respect. Cortisone and heparin inhibited definitely and slightly the reaction, respectively. A comparison was made with the modified DTH reaction and the necrotic reactions which we reported previously.

[A case of tacrolimus-induced glucose intolerance following renal allografting]

Living renal transplantation (Tx) was carried out on a 41-year-old male undergoing hemodialysis for a six-month period because of end-stage renal failure due to chronic glomerulonephritis. Tacrolimus (FK 506) was used as one of immunosuppressants. The graft worked immediately after Tx. However, his blood sugar level rose extremely high and use of insulin (IS) was required. At the second postoperative day, 0.3 mg/kg/day of FK506 was administered and the trough level (TL) was as high as 65 ng/ml. The serum IS level decreased from the pre-Tx value of 22 microU/ml to 12 microU/ml. With decrease in the dose of FK506, the TL was normalized, and the dose of IS could be decreased. FK506 has been reported to inhibit IS secretion. Therefore, we must be careful to evaluate the blood glucose level in the use of FK506 for patients with poor glucose tolerance.

[Vesico-uterine fistula after delivery: a case report]

A case of vesico-uterine fistula which occurred after natural childbirth is reported. A 33-year-old woman was admitted in February, 1993, complaining of urinary leakage from vagina immediately after natural childbirth. Excretory urogram showed an oval shaped extravasation outside the bladder, suggesting that the contrast medium went into the luminal space of the uterus. Subsequent cystoscopy showed a fistula on the posterior wall, probably the orifice of the fistula to the space. As these findings strongly suggested the vesico-uterine fistula, surgical operation was done. Rupture of the uterus was observed. Then hysterectomy was done because the rupture could not be repaired. Vesico-uterine fistula was thought to be the result of the rupture of uterus. Bladder side fistula was successfully repaired. Sixty eight cases of vesico-uterine fistula, including this case, in the Japanese literature have been reviewed and discussed the etiology, symptom and treatment.

Cytokinesis by a contractile ring in the primitive red alga Cyanidium caldarium RK-1

To better understand the mechanism of cytokinesis in eukaryotes, the behavior of the contractile ring in the two unicellular primitive red algae Cyanidioschyzon merolae and Cyanidium caldarium RK-1, which have the smallest genome size among eukaryotes, was examined by fluorescein isothiocyanate (FITC)-phalloidin fluorescence microscopy, fluorometry using a video-intensified microscope photoncounting system, transmission electron microscopy and immunoblotting techniques. Cells in each alga contained one nucleus, one mitochondrion and one chloroplast, which were aligned in that order. During cytokinesis in C. merolae, a contractile ring was not observed by fluorescence microscopy or by transmission electron microscopy. In contrast, in C. caldarium RK-1, a contractile ring appeared at the equatorial region of the dividing cells and began to contract from the side of the chloroplast. During contraction of this ring, the total fluorescent intensities due to FITC-phalloidin remained constant. Electron microscopy revealed outer and inner bands approximately 80 nm wide and 9 nm thick which ran parallel to each other just beneath the cell membrane. These bands were visible at the equator of the cell just before the initiation of cytokinesis and constricted from the pole of the chloroplast. Both bands increased in width as cleavage progressed. The inner ring consisted of a bundle of approximately 20 actin-like filaments which were arranged as a raft. In the outer ring, such fine filaments were not visible. It seems likely that the bundle of filaments, known as the contractile ring, is composed of two different elements: an inner band of actin filaments and an outer band of unknown materials.(ABSTRACT TRUNCATED AT 250 WORDS)

A histological study on experimental autoimmune myocarditis with special reference to initiation of the disease and cardiac dendritic cells

The precise mechanism of myosin-induced autoimmune myocarditis is unknown. The purpose of the present study was to define the immunohistological and ultrastructural characteristics of the infiltrating cells, especially in the initial phase of the myocarditis. It was demonstrated that OX6-positive dendritic cells first infiltrated the cardiocytes on day 13 after immunization. After day 17, OX6-positive cells, which possessed elongated irregular-shaped processes on the cell surface but contained few phago-lysosomes in the cytoplasm, were located at the margin of an inflammatory field and inserted their processes into the sarcoplasm of cardiocytes. The central portion of the inflammatory field was occupied by ED1-positive inflammatory macrophages, which were rich in phagosomes and which were in contact with degenerating cardiocytes. No evidence was obtained which suggested that lymphocytes directly injured the cardiocytes. These results demonstrated ultrastructural evidence that the type of infiltrating cell that first injures cardiocytes is the cardiac dendritic cell. Inflammatory macrophages thereafter serve as scavengers of degenerating cardiocytes.