Serositis and lymphopenia are common features of systemic lupus erythematosus following SARS-CoV-2 infection: A case report and literature review

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can affect a number of human systems, including the respiratory, cardiovascular, neurological, gastrointestinal, and musculoskeletal systems. These symptoms persist long after the acute infection has healed and is called "long COVID". Interestingly, there have been a series of reports that SARS-CoV-2 infections trigger the development of various autoimmune diseases such as systemic lupus erythematosus (SLE), inflammatory arthritis, myositis, vasculitis. Here, we report a novel case of SLE characterized by persistent pleural effusion and lymphopenia following SARS-CoV-2 infection. This is the first case in the Western Pacific region to our knowledge. Furthermore, we reviewed 10 similar cases including our case. By looking at the characteristics of each case, we found that serositis and lymphopenia are common features of SLE following SARS-CoV-2 infection. Our finding suggests that patients with prolonged pleural effusion and/or lymphopenia after COVID-19 should be checked for autoantibodies.

Superior mesenteric vein thrombosis and osteoporotic vertebral fractures

Superior mesenteric vein (SMV) thrombosis is relatively rare disease with unspecific symptoms. Thrombus formation within the SMV eventually leads to congestive intestinal necrosis. In most cases, the lack of specific symptoms makes early diagnosis difficult. Therefore, it is important to suspect the disease and actively investigate it, given a causative factor. Here, we report a case of SMV thrombosis with a novel predisposing factor, compression of SMV by deformed spine, found on contrast medium-enhanced computed tomography. Treatment with intravenous heparin followed by oral anticoagulants resulted in favorable outcome. This is the first picture showing the novel mechanism of SMV thrombus formation relating to spinal deformity. Treating osteoporosis before spinal deformity could prevent SMV thrombosis with such a mechanism.

Cell surface-expressed Ro52/IgG/HLA-DR complex is targeted by autoantibodies in patients with inflammatory myopathies

Intracellular proteins are often targeted by autoantibodies in autoimmune diseases; however, the mechanism through which intracellular molecules are targeted remains unknown. We previously found that several intracellular misfolded proteins are transported to the cell surface by HLA class II molecules and are recognized by autoantibodies in some autoimmune diseases, such as rheumatoid arthritis, antiphospholipid syndrome, and microscopic polyangiitis. Ro52 is an intracellular Fc receptor that is a target antigen for myositis-associated autoantibodies. We analyzed the role of HLA class II molecules in the autoantibody recognition of Ro52. Ro52 alone was not transported to the cell surface by HLA class II molecules; however, it was transported to the cell surface in the presence of both IgG heavy chain and HLA class II molecules to form a Ro52/IgG/HLA-DR complex. The Ro52/IgG/HLA-DR complex was specifically recognized by autoantibodies from some patients with inflammatory myopathies. We then evaluated 120 patients with inflammatory myopathies with four types of myositis-specific antibodies and analyzed the autoantibodies against the Ro52/IgG/HLA-DR complex. The specific antibodies against the Ro52/IgG/HLA-DR complex were detected in 90% and 93% of patients who were positive for anti-MDA5 and anti-ARS antibodies, respectively. In individual patients with these two inflammatory myopathies, changes in serum titers of anti-Ro52/IgG/HLA-DR-specific antibodies were correlated with the levels of KL-6 (R = 0.51 in anti-MDA5 antibody-positive DM patients, R = 0.67 in anti-ARS antibody-positive PM/DM patients with respiratory symptoms) and CK (R = 0.63 in anti-ARS antibody-positive PM/DM patients with muscle symptoms) over time. These results suggest that antibodies against Ro52/IgG/HLA-DR expressed on the cell surface could be involved in the pathogenesis of inflammatory myopathy subgroups.

Spontaneous regression of lung metastases after transarterial chemoembolization for hepatocellular carcinoma

Spontaneous regressions of primary and/or metastatic lesions have been rarely reported in hepatocellular carcinoma (HCC). Herein, we report the case of a 71-year-old man with HCC, focusing on shape changes of lung metastases over time. Lung metastasis of HCC was histologically diagnosed by percutaneous computed tomography (CT)-guided needle biopsy after the treatment of primary HCC lesion. Lung lesions had been observed on enhanced contrast computed tomography for >3 years without any local or systemic treatment for them. During this period, treatments including surgical procedure for relapsed bladder cancer and transarterial chemoembolization for HCC were performed. Metastatic lung lesions immediately regressed after these treatments. Therefore, accumulation of such cases may help elucidate spontaneous regression mechanisms in primary HCC or its lung metastases.

FcγRIIIA-mediated activation of NK cells by IgG heavy chain complexed with MHC class II molecules

Natural killer (NK) cells are a major FcγRIIIA-expressing lymphocyte population that mediate antibody-dependent cellular cytotoxicity. Although NK cells are critical for immunity against viruses and tumors, they are also activated in the joints of patients with rheumatoid arthritis (RA) and may be involved in disease progression. We previously found that human leukocyte antigen (HLA) class II molecules transport misfolded cellular proteins, such as IgG heavy chain (IgGH), to the cell surface via association with their peptide-binding grooves. Furthermore, we found that IgGHs bound to HLA class II molecules encoded by RA susceptibility alleles are specific targets for rheumatoid factor, an auto-antibody involved in RA. Here, we report that IgGHs bound to HLA class II molecules preferentially stimulate FcγRIIIA-expressing but not FcγRI-expressing cells. A significant correlation was observed between the reactivity of FcγRIIIA-expressing cells to IgGH complexed with a specific HLA-DR allele and the odds ratio for HLA-DR allele's association with RA. Moreover, primary human NK cells expressing FcγRIIIA demonstrated IFN-γ production and cytotoxicity against cells expressing IgGH complexed with HLA class II molecules. Our findings suggest that IgGH complexed with HLA class II molecules are involved in the activation of FcγRIIIA-expressing NK cells observed within arthritic joints.

Cytomegalovirus disease of the upper gastrointestinal tract in patients with rheumatic diseases: a case series and literature review

Cytomegalovirus disease of the upper gastrointestinal tract (CMV-UGT) is a rare but significant complication in patients with rheumatic diseases. We reviewed records for January 2004 to December 2012 and investigated the occurrence of CMV-UGT in patients with rheumatic diseases to evaluate clinical characteristics, the value of the CMV antigenemia assay, and the association between immunosuppressive therapy and CMV-UGT. Ten CMV-UGT events (six gastric ulcer, two esophagitis, one gastritis, and one duodenal ulcer) in nine patients (three rheumatoid arthritis, three systemic lupus erythematosus, one dermatomyositis, one systemic sclerosis, and one overlap syndrome) were identified based on pathology. Mean age was 66.5 (range, 53-76) years. The CMV antigenemia assay was negative in five cases (50 %). All ten cases received glucocorticoids and six (60 %) received pulsed glucocorticoids. Mean prednisolone dose was 31.3 (range, 7.5-40) mg/day at diagnosis. Concomitant immunosuppressive agents were used in eight cases (80 %). Considering other published cases, the most common immunosuppressive drug was cyclophosphamide (ten cases; 45 %). Notably, two of our patients who were treated with low-dose glucocorticoids plus other milder immunosuppressive drugs (methotrexate and cyclosporine) also developed CMV-UGT. Life-threatening complications such as massive bleeding or perforated ulcer occurred in two patients. These results suggest that patients receiving intensive immunosuppressive therapy such as high-dose glucocorticoids and cyclophosphamide are at higher risk for developing CMV-UGT. Moreover, CMV-UGT can occur even with low-dose glucocorticoid therapy and relatively mild immunosuppressive agents. The value of the CMV antigenemia assay for predicting CMV-UGT appears to be limited.

Cytoplasmic gamma actin as a Z-disc protein

To investigate the precise localization of cytoplasmic gamma actin in skeletal muscle and the relationship to dystrophin molecules, we designed an antibody against the N-terminal peptide of cytoplasmic gamma actin. Western blot analysis using SDS-PAGE and isoelectric focusing (IEF) gel revealed that the antibody reacted only with the actin isoforms having gamma motility, confirming that the antibody is specific to the cytoplasmic (nonmuscle) gamma actin. Immunohistochemical analysis of the skeletal muscle of the adult mouse revealed a dot-like staining pattern of the antibody in transverse sections and a striated staining pattern in longitudinal sections. The double immunostaining technique revealed the colocalization of cytoplasmic gamma actin with alpha-actinin, implying the localization of the actin on the Z-disc. Contrary to previous findings (1), we did not detect the colocalization of cytochrome oxidase, a mitochondria marker, with this actin.

Neurofilaments of Klotho, the mutant mouse prematurely displaying symptoms resembling human aging

We reported previously that neurofilaments (NFs) of aged rats were highly packed in the axon and contained a smaller amount of NF-M as compared with those of young rats (Uchida et al. [1999] J. Neurosci. Res. 58:337-348). We studied NFs of the mutant mouse, named Klotho, which displays prematurely symptoms resembling human aging. The transport of axonal cytoskeletal proteins, including NFs, tubulin and actin, was decreased at the leading portion of the peak of transported proteins in Klotho during the process of premature aging. The nearest neighbor inter-NF distance in Klotho axons (35-39 nm) was shorter than that of the wild-type mouse (48-49 nm), indicating the packing of NFs in Klotho. The ratio of NF-M to NF-L was slightly decreased in cytoskeletons from the spinal cords of Klotho. These changes are similar, though not identical, to those observed in aged rats, and are the first evidence of age-related changes in the neurons of Klotho.

Expression of dystroglycan complex in satellite cells of dorsal root ganglia

In Schwann cells, the transmembrane glycoprotein beta-dystroglycan composes the dystroglycan complex together with the extracellular glycoprotein alpha-dystroglycan, which binds laminin-2 (alpha2/beta1/gamma1), a major component of the Schwann cell basal lamina. In the Schwann cell cytoplasm, beta-dystroglycan is anchored to a dystrophin isoform, Dp116. In this study, we investigated the expression of beta-dystroglycan, Dp116 and the laminin-alpha2 chain in satellite cells of rat dorsal root ganglia (DRGs). Immunohistochemical study showed that immunoreactivities for beta-dystroglycan and Dp116 were both localized to the outer rim of neuron-satellite cell and axon-Schwann cell units, indicating that both satellite and Schwann cells expressed these proteins in DRGs. Immunoreactivity for the laminin-alpha2 chain was detected in a similar location, indicating that the basal lamina surrounding satellite and Schwann cells in DRGs contained laminin-2. Ultrastructurally, immunoreactivity for the cytoplasmic domain of beta-dystroglycan as well as that for Dp116 was most intense in the cytoplasm just underlying the outer membrane of satellite cells. The immunoreactivity for laminin was associated with the outer surface of those cells, suggesting that it was localized in the surrounding basal lamina. These results indicate that the dystroglycan complex is expressed in the satellite cell outer membrane and involved in the adhesion with the basal lamina through the interaction with laminin-2.

Caveolin-3 deficiency causes muscle degeneration in mice

Caveolin-3 is a muscle-specific protein integrated in the caveolae, which are small invaginations of the plasma membrane. Mutations of the caveolin-3 gene, localized at 3p25, have been reported to be involved in the pathogenesis of limb-girdle muscular dystrophy (LGMD1C or caveolinopathy) with mild clinical symptoms, inherited through an autosomal dominant form of genetic transmission. To elucidate the pathogenetic mechanism, we developed caveolin-3-deficient mice for use as animal models of caveolinopathy. Caveolin-3 mRNA and its protein were absent in homozygous mutant mice. In heterozygous mutant mice, both the mRNA and its protein were normal in size, but their amounts were reduced by about half. The density of caveolae in skeletal muscle plasma membrane was roughly proportional to the amount of caveolin-3. In homozygous mutant mice, muscle degeneration was recognized in soleus muscle at 8 weeks of age and in the diaphragm from 8 to 30 weeks, although there was no difference in growth and movement between wild-type and mutant mice. No apparent muscle degeneration was observed in heterozygous mutant mice, indicating that pathological changes caused by caveolin-3 gene disruption were inherited through the recessive form of genetic transmission.

Expression of a system L neutral amino acid transporter at the blood-brain barrier

Amino acid transport system L has been proposed to be one of the major nutrient transport systems at the blood-brain barrier. Using immunohistochemical analyses, a system L transporter LAT1 was shown to be expressed in the brain capillary endothelial cells in rats. Because LAT1 was coexpressed with 4F2 heavy chain which brings LAT1 to the plasma membrane, LAT1 is proposed to be functional in the plasma membrane of brain capillary endothelial cells. Both LAT1 and 4F2hc immunoreactivities were detected in a double line appearance surrounding endothelial cell nuclei, suggesting both proteins are present in the luminal and abluminal membranes. LAT1 is, thus, a blood-brain barrier system L transporter responsible for the permeation of aromatic or branched-chain amino acids and amino acid-related drugs such as L-DOPA.

Brain-derived neurotrophic factor-induced phosphorylation of neurofilament-H subunit in primary cultures of embryo rat cortical neurons

Phosphorylation of the neurofilament-H subunit (NF-H) was investigated in rat embryonic brain neurons in culture. A portion of the NF-H was phosphorylated in vivo at embryonic day 17 when brain neurons were prepared. When the neurons were isolated and cultured, the NF proteins disappeared once and then reappeared over the next several days in the following order: (1) NF-L/NF-M, (2) dephosphorylated NF-H and (3) phosphorylated NF-H. Phosphorylation of NF-H began around 4 days after cell plating, at about the time of synapse formation. Treatments that appeared to modulate the timing of synapse formation also affected the timing of NF-H phosphorylation: (1) earlier phosphorylation was observed at higher neuronal cell density, (2) earlier phosphorylation was observed in neurons cultured on a coating substrate that promotes rapid neurite extension and (3) phosphorylation was suppressed when neurite extension was inhibited by brefeldin A. Three possible synapse formation-induced events, excitation, cell-cell contact through adhesion proteins and elevated concentrations of neurotrophic factors, were examined for their possible involvement in generating the signal for NF-H phosphorylation. Neither excitation nor cell contact enhanced NF-H phosphorylation. Neurotrophic factors, brain-derived neurotrophic factor (BDNF) and neurotrophin 3 (NT3) stimulated phosphorylation of NF-H. The BDNF-stimulated phosphorylation was inhibited by an anti-BDNF antibody and K252a, an inhibitor of BDNF receptor TrkB tyrosine kinase. Among known NF-H kinases of cyclin-dependent kinase 5 (CDK5), external signal-regulated protein kinase (ERK) and stress-activated protein kinase (SAPK), CDK5 and SAPK showed an increase in kinase activity or an active form with a time course similar to NF-H phosphorylation in control culture. On the other hand, BDNF stimulated the kinase activity of CDK5 and induced appearance of an active form of ERK transiently. These results suggest a possibility that synapse formation induces NF-H phosphorylation, at least in part, through activation of CDK5 by BDNF.

Expression of dystroglycan and laminin-2 in peripheral nerve under axonal degeneration and regeneration

In Schwann cells, the transmembrane glycoprotein beta-dystroglycan composes the dystroglycan complex, together with the extracellular glycoprotein alpha-dystroglycan which binds laminin-2, a major component of the Schwann cell basal lamina. To provide clues to the biological functions of the interaction of the dystroglycan complex with laminin-2 in peripheral nerve, the expression of beta-dystroglycan and laminin-alpha2 chain was studied in rat sciatic nerves undergoing axonal degeneration and regeneration as well as in normal condition. In normal sciatic nerve, immunoreactivity for the cytoplasmic domain of beta-dystroglycan was consistently and selectively localized in the Schwann cell cytoplasm underlying the outer (abaxonal) membrane apposing the basal lamina. While beta-dystroglycan expression was gradually down-regulated in Schwann cells losing contact with axons during axonal degeneration, it was progressively up-regulated as the regenerating process of ensheathment and myelination proceeded during regeneration. Interestingly, beta-dystroglycan expression, when detectable, was always restricted to the Schwann cell cytoplasm beneath the outer membrane apposing the basal lamina during both axonal degeneration and regeneration. Furthermore, laminin-alpha2 immunoreactivity roughly paralleled that of beta-dystroglycan during both axonal degeneration and regeneration, indicating that the expression of beta-dystroglycan and laminin-alpha2 is induced and maintained by the Schwann cell contact with axons. Our results indicate that the dystroglycan complex is involved in the adhesion of the Schwann cell outer membrane with the basal lamina and suggest that the dystroglycan complex may play a role in the process of Schwann cell ensheathment and myelination through the interaction with laminin-2.

Morphological evidence of the inhibitory effect of taxol on the fast axonal transport

The short term effects of taxol, a stabilizing drug of microtubules, on the peripheral nerves in the rat was investigated using a new chamber system which can be applied to incubate a sciatic nerve with various solutions in vivo. A functional analysis of retrograde axonal transport using rhodamine-labeled wheat germ agglutinin (WGA-rhodamine) showed the inhibitory effect of the drug. An electron microscopic study also revealed that a variety of vesicles were observed to accumulate on both the proximal and the distal sides of the chamber, however, no significant increase in the number of microtubules in the axons, based on the pharmacological effect of the drug, was observed even though one had been expected. These findings support the inhibitory effect of taxol on the fast axonal transport of the neurons. Furthermore, the accumulated vesicles were morphologically different from those accumulated by ligation. These results suggest that a special component of the fast axonal transport was thus selectively blocked by the drug.

Centrally nucleated fibers (CNFs) compensate the fragility of myofibers in mdx mouse

Centrally nucleated fibers (CNFs) are the myofibers which have nuclei in the center of cytoplasm, and are generally recognized as regenerated myofibers. They are commonly observed in the histopathology of the patients with several types of muscular dystrophies and their animal models. In the mdx mouse, an animal model of Duchenne muscular dystrophy, CNFs are more resistant than non-CNFs to mechanical stresses, as evidenced by the Evans blue infiltration. In relation to the population among muscles, CNFs are supposed to compensate the fragility of muscular tissue in muscular dystrophies and their animal models.

Neurofilaments of aged rats: the strengthened interneurofilament interaction and the reduced amount of NF-M

Amyotrophic lateral sclerosis is an age-related neurological disease, characterized by neurofilament (NF) accumulation in primary axons followed by degeneration of motor neurons. To elucidate age-related factors that might lead to pathological NF accumulation, NFs were compared between young and aged rats. Electron microscopic examination of sciatic nerve axons revealed that NFs were more than twice as densely packed in aged rat axons (542 +/- 180 NFs/mm2) as in young adult rat axons (211 +/- 73 NFs/mm2). The NFs isolated from aged rats also appeared to be more aggregated than those from young rats. Phosphorylation at the head or tail domains was studied as a possible candidate affecting NF organization. Western blotting with phosphorylation-dependent antibodies showed higher phosphorylation of NF-H in the tail domains of aged rat spinal cord NFs, but dephosphorylation did not diminish the differences in aggregation between aged and young rat NFs. On the other hand, when NFs were phosphorylated by A-kinase on their head domains, the extent of phosphorylation in NF-M of aged rat NFs was only one-third of young rat NFs. We found that aged rat NFs contained only 60% of the NF-M of young rat NFs in molar ratio compared to NF-L. These results raise a possibility that the decreased amount of NF-M induces the aggregates of isolated NFs and the higher packing density of NF in aged rat axons.

Distinct regions specify the nuclear membrane targeting of emerin, the responsible protein for Emery-Dreifuss muscular dystrophy

Emery-Dreifuss muscular dystrophy is a neuromuscular disorder that has three characteristics: (a) early contracture of the elbows, Achilles tendons and postcervical muscles; (b) slowly progressive wasting and weakness of skeletal muscle; and (c) cardiomyopathy with severe conduction block. The responsible gene for the X-linked recessive form of this disease encodes an inner nuclear membrane protein named emerin. Although emerin is absent in tissues from patients with this disorder, it remains obscure why the loss of this widely expressed protein affects selectively skeletal muscle, heart and joints. As the first step to address this question, we examined the molecular regions of emerin that are essential for nuclear membrane targeting and stability of the protein. We found that the C-terminal hydrophobic region was necessary, but not sufficient, for nuclear membrane anchoring and stability of the protein. In the absence of this transmembrane domain, the upstream nucleoplasmic domain showed no firm association with the nuclear rim, but showed the tendency to accumulate at the nucleolus-like structures. Furthermore, proper targeting of emerin to the nuclear membrane required the latter half of the nucleoplasmic domain. These characteristics are distinct from those of lamina-associated polypeptide 2. Our findings indicate that emerin has distinct interactions with the inner nuclear membrane components that may be required for the stability and function of rigorously moving nuclei in tissues such as skeletal muscle, heart and joints.

Ethidium bromide-induced inhibition of mitochondrial gene transcription suppresses glucose-stimulated insulin release in the mouse pancreatic beta-cell line betaHC9

Recently, a mitochondrial mutation was found to be associated with maternally inherited diabetes mellitus (Kadowaki, T., Kadowaki, H., Mori, Y., Tobe, K., Sakuta, R., Suzuki, Y., Tanabe, Y, Sakura, H., Awata, T., Goto, Y., Hayakawa, T., Matsuoka, K., Kawamori, R., Kamada, T., Horai, S., Nonaka, I., Hagura, R., Akanuma, Y., and Yazaki, Y. (1994) N. Engl. J. Med. 330, 962-968). In order to elucidate its etiology, we have investigated the involvement of mitochondrial function in insulin secretion. Culture of the pancreatic beta-cell line, betaHC9, with low dose ethidium bromide (EB) (0.4 microg/ml) for 2-6 days resulted in a substantial decrease in the transcription level of mitochondrial DNA (to 10-20% of the control cells) without changing its copy number, whereas the transcription of nuclear genes was grossly unaffected. Electron microscopic analysis revealed that treatment by EB caused morphological changes only in mitochondria and not in other organelles such as nuclei, endoplasmic reticula, Golgi bodies, or secretory granules. When the cells were treated with EB for 6 days, glucose (20 mM) could no longer stimulate insulin secretion, while glibenclamide (1 microM) still did. When EB was removed after 3- or 6-day treatment, mitochondrial gene transcription recovered within 2 days, and the profiles of insulin secretion returned to normal within 7 days. Studies with fura-2 indicated that in EB-treated cells, glucose (20 mM) failed to increase intracellular Ca2+, while the effect of glibenclamide (1 microM) was maintained. Our system provides a unique way to investigate the relationship between mitochondrial function and insulin secretion.

X-ray microanalysis and phagocytotic activity of cultured retinal pigment epithelial cells in hypoxia

PURPOSE

To investigate the influence of the functional and morphological changes induced in retinal pigment epithelial (RPE) cells by retinal ischemia, we evaluated the phagocytotic activity, the concentration of various elements, and ultrastructure in cultured RPE cells in hypoxia.

METHODS

The concentrations of oxygen in incubators were adjusted to 20, 10, and 1% by the addition of nitrogen for 72 hr. To observe phagocytotic activity and its relationship to actin filaments, the filaments of RPE cells incubated with fluoresbrite carboxylate YG microspheres were stained with rhodamine phalloidin. Some of the specimens were subjected to X-ray microanalysis by scanning electron microscope after being fixed, freeze-dried, and coated with carbon to investigate the cytoplasmic concentration of elements. A part of the latter specimens was also observed by transmission electron microscope after being embedded in epon and cut into ultrathin sections to see the ultrastructural changes inside cell.

RESULTS

Lowering oxygen concentrations from 20% to 1% swelled RPE cells and decreased the number of fluoresbrite carboxylate YG microspheres phagocytized by RPE cells. Phagocytosis of a large amount of latex beads (30 microl) for 24 hr in 1% oxygen caused a disruption of RPE cells. Na, S, and P were detected in RPE cells cultured in 20% oxygen. Reducing the oxygen concentration from 20 to 10 or 1% significantly decreased Na and increased S. Mitochondria were observed in RPE cells in 20 and 10% oxygen, but many vacuoles were observed in the cytoplasm in 1% oxygen.

CONCLUSION

Hypoxia as low as 1% oxygen induced malfunction of phagocytosis and the fragility of RPE cells. We could speculate the imbalance of the electrolytes such as Na or a decrease of antioxidants such as glutathione containing S as a reason of disturbance of cell viability.

Emerin, deficiency of which causes Emery-Dreifuss muscular dystrophy, is localized at the inner nuclear membrane

X-linked recessive Emery-Dreifuss muscular dystrophy (EDMD) is an inherited muscle disorder characterized by the clinical triad of progressive wasting of humero-peroneal muscles, early contractures of the elbows, Achilles tendons and postcervical muscles, and cardiac conduction block with a high risk of sudden death. The gene for EDMD on Xq28 encodes a novel protein named emerin that localizes at the nuclear membrane of skeletal, cardiac and smooth muscles and some other non-muscle tissues. To investigate a possible physiological role for emerin, we examined the ultrastructural localization of the protein in human skeletal muscle and HeLa cells, using ultrathin cryosections. We found that the immune-labeled colloidal gold particles were localized on the nucleoplasmic surface of the inner nuclear membrane, but not on the nuclear pore. Emerin stayed on the cytoplasmic surface of the nuclear lamina, even after detergent treatment that solubilizes membrane lipids and washes out membrane proteins. These results suggest that emerin anchors at the inner nuclear membrane through the hydrophobic stretch, and protrudes from the hydrophilic region to the nucleoplasm where it interacts with the nuclear lamina. We speculate that emerin contributes to maintain the nuclear structure and stability, as well as nuclear functions, particularly in muscle tissues that have severe stress with rigorous contraction-relaxation movements and calcium flux.

Subglottic branch of the superior laryngeal nerve in the dog penetrates the cricoid cartilage

The topographic anatomical study on the distribution pattern of the superior laryngeal nerve (SLN) in the larynx was studied in thirteen adult dogs. The ramus posterior of the SLN divides into two branches; the interarytenoid branch (IA) and the pharyngoesophageal branch (PE). The IA on both sides connect to the cricoid ganglion (CG) in the midline at the cranial border of the cricoid cartilage. Posterior glottic branches arise from the IA, run over the cricoid cartilage, and distribute fibers to the posterior wall of the glottis. Every specimen observed in the present study possessed the CG and the posterior glottic branches. The subglottic branch derives from the IA near the cricoid ganglion, and passes through the cricoid foramen (CF) (Yoshida, 1986). The subglottic branch distributes fibers to the subglottic mucous membrane covering the cricothyreoid ligament. The CF and the subglottic branch were observed on both sides of seven specimens out of thirteen dogs. They were also observed on only one side in three specimens, and were not detectable on either side in the three remaining specimens. The silver impregnation applied in the semimicroscopic dissection facilitated identification of the precise localization and the topographic arrangement of ganglia and nerve bundles.

Comparative effects of linoleic acid and linoleic acid hydroperoxide on growth and morphology of bovine retinal pigment epithelial cells in vitro

PURPOSE

Outer segments of the photoreceptor rods that are phagocytized by the retinal pigment epithelial (RPE) cells contain a high proportion of polyunsaturated fatty acids (PUFA). PUFA are susceptible to lipid peroxidation. We hypothesized that the resulting peroxides could injure RPE cells leading to retinal degeneration. Accordingly, we compared the effects of linoleic acid (LA) and its hydroperoxide (LHP) on the growth and morphology of RPE cells using laser scanning microscopy and transmission microscopy.

METHODS

We counted the number of RPE cells after incubation for 24 and 48 hrs with concentrations of LA or LHP of 0.035, 0.175, and 0.35 mM. To observe the actin filaments, cultured RPE cells were stained with rhodamine phalloidin. The cells were prefixed with 2% glutaraldehyde and postfixed in 1% osmium tetroxide. Specimens were embedded in Epon 812 after dehydration, and the ultrathin sections were doubly stained with 2% uranyl acetate and 2% lead acetate for examination by transmission electron microscopy.

RESULTS

Exposure to LA or LHP produced dose-dependent damage to RPE cells with a significantly greater effects of LHP than LA. After incubation for 24 hrs with 0.35 mM LA, the number of vacuoles in RPE cells exceeded that observed in control RPE cells by 365 nm laser microscopy. Exposure to 0.35 mM LHP for 24 hrs produced a pycnotic nucleus, with diffuse and granular autofluorescences observed in and around it. Exposure of RPE cells to 0.35 mM LA for 24 hrs showed that the LA incorporated into the lysosomes was digested and released extracellularly from lysosomes via exocytotic vesicles. However, such exposure to LHP damaged the RPE cells, including the membranes in the pinocytotic vesicles. The packed membranes resembled myelin.

CONCLUSIONS

While the LA incorporated into the lysosomes was released extracellularly, LHP persisted in the RPE cells, being observed as autofluorescent lipofuscin-like materials. LHP was cytotoxic, and caused damage to the membranes of pinocytotic vesicles and lysosomes.

Physical dissociation of the TCR-CD3 complex accompanies receptor ligation

Recent studies indicate that there may be functional uncoupling of the TCR-CD3 complex and suggest that the TCR-CD3 complex is composed of two parallel signal-transducing units, one made of gamma delta epsilon chains and the other of zeta chains. To elucidate the molecular mechanisms that may explain the functional uncoupling of TCR and CD3, we have analyzed their expression by using flow cytometry as well as immunochemical means both before and after stimulation with anti-TCR-beta, anti-CD3 epsilon, anti-CD2, staphylococcal enterotoxin B, and ionomycin. We present evidence that TCR physically dissociates from CD3 after stimulation of the TCR-CD3 complex. Stimulation with anti-CD3 resulted in down-modulation of TCR within 45 min whereas CD3 epsilon was still expressed on the cell surface as detected by flow cytometry. However, the cell surface expression of TCR and CD3 was not affected when cells were stimulated with anti-TCR-beta under the same conditions. In the case of anti-CD3 treatment of T cells, the TCR down-modulation appeared to be due to the internalization of TCR, as determined by immunoelectron microscopy. Immunochemical analysis of cells after stimulation with either anti-TCR or anti-CD3 mAbs revealed that the overall protein levels of TCR and CD3 were similar. More interestingly, the dissociation of the TCR-CD3 complex was observed with both treatments and occurred in a manner that the TCR and the associated TCR-zeta chain dissociated as a unit from CD3. These results provide the first report of physical dissociation of TCR and CD3 after stimulation through the TCR-CD3 complex. The results also suggest that the signal transduction pathway triggered by TCR may differ from that induced by CD3.

A novel type of cell death of lymphocytes induced by a monoclonal antibody without participation of complement

A monoclonal antibody, RE2, raised by immunizing a rat with cell lysate of a mouse T cell clone, was found to directly kill interleukin 2-dependent T cell clones without participation of serum complement. Fab fragments of RE2 had no cytolytic activity, while the cross-linking of Fab fragments with anti-rat immunoglobulin reconstituted the cytotoxicity. The cytotoxicity was temperature dependent: the antibody could kill target cells at 37 degrees C but not at 0 degrees C. Sodium azide, ethylenediaminetetraacetic acid, and forskolin did not affect the cytolytic activity of RE2, while the treatment of target cells with cytochalasin B and D completely blocked the activity. This suggested that the cell death involves a cytoskeleton-dependent active process. Giant holes on the cell membrane were formed within 5 minutes after the treatment with RE2, as observed by scanning electron microscopy. There was no indication of DNA fragmentation nor swelling of mitochondria during the cytolysis, suggesting that the cell death is neither apoptosis nor typical necrosis. The antibody also killed T cell lymphomas and T and B cell hybridomas only when these cells were preactivated with concanavalin A, lipopolysaccharide, or phorbol myristate acetate. Preactivated peripheral T and B cells were sensitive to the cytotoxicity of RE2, while resting T and B cells were insensitive. These results provide evidence for a novel pathway of cell death of activated lymphocytes by membrane excitation.

Young female patient with testosterone-producing adrenocortical adenoma also showing signs of subclinical Cushing's syndrome

A 28-year old female patient with virilization due to left adrenocortical adenoma was studied. The patient had clinical features of hyperandrogenism such as hirsutism and a low pitched voice, but not of hypercorticoidism. Plasma testosterone and dehydroepiandrosterone-sulfate (DHEA-S) were high. Although the basal plasma cortisol concentration and urinary excretion of 17-hydroxycorticosteroids (17-OHCS) were within the normal range, the absence of diurnal variation in plasma cortisol and loss of suppressibility by dexamethasone suggested constitutive secretion of cortisol by the tumor. Inappropriate cortisol secretion was also supported by blunted ACTH response to provocative stimuli. After successful removal of the left adrenal tumor, such endocrinological abnormalities were all normalized. Immunohistochemical analysis revealed that tumor cells were positively stained for C21 hydroxylase cytochrome P-450 (P-450C21) and P-450(11) beta which convert 17-hydroxy (OH) progesterone to cortisol as well as P-450SCC, 3 beta-hydroxysteroid dehydrogenase and P-450(17) alpha which are involved in testosterone biosynthesis. These findings suggest that adrenocortical adenoma secretes predominantly testosterone and constitutively cortisol in a young woman patient with virilization.

Components of the mylohyoid nerve degenerate during evolutionary progress in primates

The vibrissal, cutaneous and muscular branch of the mylohyoid nerve was studied on both sides in 67 individuals in 16 species of 14 genera (Rattus, Canis, Felis, Suncus, Talpa, Tupaia, Lemur, Nicticebus, Galago, Pithecia, Ateles, Papio, Macaca, Pan) with particular reference to the phylogenic change of these branches. In this series of studies in rats, dogs, cats, tree shrews, and 5 sides out of 30 crab-eating monkeys, a fine branch of the mylohyoid nerve proceeds to the vibrissal hair follicle. The vibrissal branch passes through the platysma and enters the vibrissal hair follicle at the middle of the body. It is conceivable that the intermandibular vibrissae had been reduced from the intermandibular skin during the phylogenic progress of prosimians. The vibrissal branch of the mylohyoid nerve may retire from the intermandibular region according to the disappearance of the intermandibular vibrissae. The cutaneous branches of the mylohyoid nerve were detectable in almost all of the specimens. The cutaneous branch seems to be retained despite the reduction of the intermandibular vibrissae in primates. It must be considered to retire from the intermandibular skin during the evolutional progress of the hominids. In spite of the alteration of the muscular arrangement, the mylohyoid nerve is preserved as the innervation to the anterior belly of the digastric muscle and to the mylohyoid muscle in all specimens examined.

Competition between motor molecules (kinesin and cytoplasmic dynein) and fibrous microtubule-associated proteins in binding to microtubules

In neuronal cells, microtubule-associated proteins (MAPs) can be classified into two distinct groups. One consists of force-producing MAPs, the main components of which are kinesin and cytoplasmic dynein. The other is composed of fibrous MAPs, which include tau and MAP2. Many studies have been performed on the respective groups to understand their structures and functions. However, the problem of how the groups interact with each other on microtubules is still unresolved. To elucidate the interaction between kinesin or cytoplasmic dynein and tau or MAP2, we performed three experiments: competition, motility assay, and cosedimentation. To distinguish whether the binding competition is caused by steric hindrance of the projection domains of MAPs or by the competition of the binding sites on microtubules, we used microtubule binding domains of tau and MAP2 as well as native proteins. Our results revealed that kinesin or cytoplasmic dynein and tau or MAP2 complete for almost the same binding domains located on the carboxyl-terminal side of alpha- and the amino-terminal side of beta-tubulin from the site of subtilisin cleavage. Furthermore, the projection of tau, and probably of MAP2, might inhibit the binding of kinesin or cytoplasmic dynein to microtubules by steric hindrance. These findings will provide a useful step toward understanding the regulation system of intracellular organelle transport.

[Fluctuation of plasma levels of fibrinogen degradation products, fibrin degradation products and total fibrin/fibrinogen degradation products in patients with DIC]

Ten patients with disseminated intravascular coagulation syndrome (DIC) were analyzed using three enzyme linked immunosorbent assays (ORGANON TEKNIKA, Belgium) for fibrin degradation products (FbDP), fibrinogen degradation products (FgDP) and total fibrin/fibrinogen degradation products (TDP). A significant elevation in each parameter and a significant depression of FgDP/FbDP (g/b) ratio were observed in the patients in early stage of DIC, comparing with normal individuals (p < 0.001 and p < 0.01). These results suggested that both fibrinolysis and fibrinogenolysis were marked accelerated, with a superiority in fibrinolysis in those patients. The levels of these parameters decreased and the g/b ratio increased with the passage of the clinical courses in five patients who were improved. Although in five deteriorated cases, the levels were kept high and their g/b ratio showed low continuously. These findings suggested that separated monitoring of fibrinolysis or fibrinogenolysis was useful to study patients with DIC and g/b ratio could be regarded as a helpful indication of therapeutic effects.

[Thrombocytopenia in HIV-1 seropositive hemophiliacs]

When platelet counts were compared in 1986 and 1992 in 117 anti-HIV antibody positive and negative hemophilia patients, a clear decrease was found in the positive group. In 1992 platelet counts < 150 x 10(9) were present in 23.5% of the positive group in contrast to 5.8% of the negative group. Comparing platelet counts with other clinical parameters, a positive correlation was found with cholinesterase and a negative correlation with IgG in both the positive and negative groups, while negative correlations with beta 2-microglobulin and platelet-associated IgG were found in only the positive group. These findings implicate the chronic liver dysfunction present in hemophilia patients, apart from HIV infection, in the decrease in platelet counts, with immunodeficiency playing an additional role in the positive group. In the treatment of a hemophilia B patient showing decreased platelet counts, these counts increased consistent with the administration of Acyclovir and Zidovudine. It was demonstrated that HSV-1 and HIV-1 antigen are present on the soluble platelets of this patient and are recognized by antibodies in the patient's serum.

[Levels of serum lactate dehydrogenase and its isozymes with relation to clinical features of pneumocystis carinii pneumonia in acquired immunodeficiency syndrome patients]

The clinical courses of 9 patients with acquired immunodeficiency syndrome (AIDS) complicated by pneumocystis carinii pneumonia (PCP) were followed to investigate the clinical significance of the measurement of various parameters such as serum lactate dehydrogenase (LDH). The mean duration of symptoms before diagnosis was 20 days, and the median duration of therapy was 29.5 days. Serum LDH activity increased in 8 of 9 cases. The isozyme pattern in all cases was characterized by high LDH3 values from the early stage. However, inflammatory markers did not increase in most cases. There were good correlations between the levels of LDH, clinical course, and PaO2.

The phosphorylation of kinesin regulates its binding to synaptic vesicles

Membrane organella are transported bidirectionally in cells, and the axonal transport system has provided an ideal model system for studying this bidirectional transport. Kinesin and cytoplasmic dynein were identified as candidates for the motor molecules of fast axonal transport, which transport organella along microtubules anterogradely and retrogradely. However, the mechanism that controls this bidirectional transport is unknown. Our previous work revealed that kinesin in axons was associated abundantly with anterogradely transported membranous organella, most of which are believed to be precursors of synaptic vesicles and axonal plasma membranes, while the fractions bound to retrogradely transported ones were very small (Hirokawa, N., Sato-Yoshitake, R., Kobayashi, N., Pfister, K. K., Bloom, G. S., and Brady, S. T. (1991) J. Cell Biol. 114, 295-302). Here we demonstrated in vitro that the binding of kinesin to synaptic vesicles was concentration-dependent and saturable and could be released by high salt concentration. When kinesin was phosphorylated by cAMP-dependent protein kinase, its binding to symaptic vesicles was significantly reduced. By motility assay and by statistical analysis using electron microscopy, we further revealed that synaptic vesicles preincubated with phosphorylated kinesin associated less frequently with microtubules than synaptic vesicles preincubated with unphosphorylated kinesin. The phosphorylation of kinesin should therefore play an essential role in regulating the direction of fast axonal transport by inhibiting its binding to membrane organella, thus releasing it from membrane organella at nerve terminals.

[HIV-1 seropositive hemophilia A complicated by disseminated intravascular coagulation syndrome and acute pancreatitis during treatment of Pneumocystis carinii pneumonia]

Pneumocystis carinii pneumonia (PCP) is a major opportunistic infection in acquired immunodeficiency syndrome (AIDS) and is treated with co-trimoxazole, pentamidine and others. The severe adverse reactions, including bone marrow suppression, by these therapeutic agents often preclude their continued use. A 14-year-old male HIV-positive hemophilia A patient, who was complicated by disseminated intravascular coagulation syndrome (DIC) following acute pancreatitis during treatment for PCP, was treated with proteinase inhibitors and anticoagulant agents. He was improved and discharged. As pentamidine may cause pancreatitis and develop DIC, it is important that pancreatic enzymes should be carefully followed when this agent administrated. In this case, granulocyte colony-stimulating factor and erythropoietin were effective for the bone marrow suppression, suggesting that importance of these agents for the prophylaxis of other secondary infections during the treatment.

Herpes simplex virus type 1 and human immunodeficiency virus type 1 antigens in platelets from a hemophilia B patient with human immunodeficiency virus type 1-related thrombocytopenia

We analyzed platelet-associated antigens from a hemophilia B patient with human immunodeficiency virus type 1 (HIV-1)-related thrombocytopenia. Two bands appeared at 31,000 and 37,000 daltons in the platelet lysate after reaction with autologous serum in SDS-PAGE and Western blots. The band at 37,000 daltons was obtained using anti-herpes simplex type 1 (HSV-1) rabbit antiserum. Doublet bands at 36,000 and 37,000 daltons also appeared after reaction with HSV-1 seropositive human serum. The band at 31,000 daltons appeared after reaction with anti-HIV-1 rabbit serum. These results suggest that the platelet-associated antigens in this patient are components of both HSV-1 and HIV-1 antigens. In addition, acyclovir decreased his PAIgG level and increased his platelet count, and zidovudine increased his platelet count. Thus, we concluded that each of the platelet-associated antigens is partially responsible for the thrombocytopenia by causing deposition of immune complexes in this patient.

[Evaluation of an enzyme immunoassay for plasma thrombomodulin]

Thrombomodulin (TM) is an endothelial cell membrane glycoprotein which neutralizes thrombin clotting activity and accelerates thrombin-catalyzed activation of plasma protein C. Its role is considered to be very important to prevent thrombosis. Recently, TM has been found in circulating blood and the roles and the functions have been investigated. In this study, we evaluated the reliance and the clinical usefulness of a TM-measuring-kit by enzyme immunoassay (MGC-01-001: Mitsubishi Gas chemical company). Intraassay reproducibility test, dilution linearity test and in vitro recovery test was obtained satisfactory results. A correlation between plasma and serum on TM levels of healthy individuals was very good and the difference between them was not significant. Normal value of plasma TM levels was instituted 15.73 +/- 6.98 ng/ml by measuring 52 healthy adults. The difference between male and female was not significant. Plasma TM levels did not change significantly after venous occlusion test and on circadian fluctuation. Plasma TM levels in patients with occlusion test and on circadian fluctuation. Plasma TM levels in patients with disseminated intravascular coagulation (DIC) was 40.15 +/- 22.68 ng/ml (mean +/- SD, n = 14). It is significantly higher than the levels in healthy adults. However, the levels in patients with angina pectoris, acute myocardial infarction and aortic aneurysm were not significantly different from those of healthy adults. These findings suggest that the precision of this TM-measuring-kit is satisfactory and the measurement of plasma TM can be useful to diagnose of DIC.

[Differentiation between fibrin degradation products and fibrinogen degradation products by using newly developed ELISAs]

We should distinguish fibrin degradation products (FbDP) from fibrinogen degradation products (FgDP) in order to analyze fibrinolysis in vivo. We analyzed some disorders associated with hyperfibrinolytic states using ELISA for FbDP, FgDP and total fibrin (ogen) degradation products (TDP) (ORGANON TEKNIKA). Each ELISA was useful in terms of reproducibility and dilution linearity of plasma samples. There was no cross-reaction between FbDP and FgDP. The FgDP/FbDP ratio in normal individuals was 1.65. In patients with DIC, it was 0.43, with FgDP level being increased. These results suggest that fibrinolysis is enhanced in patients with DIC, but it is accompanied by fibrinogenolysis. On the other hand, the FgDP/FbDP ratio in patients given urokinase (UK) was 2.88. This suggests that fibrinogenolysis is enhanced in them. In our study, the FgDP/FbDP ratio increased as DIC improved. Thus, we can regard this as an index of therapeutic effects in patients with DIC. We conclude that these three ELISA are useful in analyzing disorders associated with hyperfibrinolytic states.

Localization and subcellular distribution of smg p25A, a ras p21-like GTP-binding protein, in rat brain

We have made a monoclonal antibody which specifically recognizes smg p25A among many ras p21/ras p21-like GTP-binding proteins thus far purified from bovine brain membranes. By use of this antibody, we have investigated the localization and subcellular distribution of smg p25A in rat brain by light and electron microscopic immunocytochemistry and by immunoblotting. By light microscopic immunocytochemistry, specific immunoreactivity is widely distributed, most abundant in neuropil, weak in neuronal somata, and absent from white matter. By electron microscopic immunocytochemistry, intense labeling is demonstrated on most of the synapses and concentrated in the presynaptic area where synaptic vesicles are observed. Presynaptic plasma membranes are weakly labeled but mitochondria, postsynaptic plasma membranes, and postsynaptic densities are unlabeled. In subcellular fractionation analysis of cerebrum, about one-fifth of smg p25A is found in the soluble cytosol fraction and the rest is found in the particulate fraction. About half of the particulate-bound smg p25A is recovered in the P2 fraction containing synaptosomes, mitochondria, and myelin, among which a major portion of smg p25A is recovered in the synaptosomal fraction. In the synaptosomal fraction, smg p25A is concentrated about 8-fold in the fraction containing synaptic vesicles and about 3-fold in the fraction containing synaptic plasma membranes compared with the original homogenate. smg p25A is present at a low level in the fraction containing synaptosomal soluble substances but almost absent from the fractions containing intrasynaptosomal mitochondria or post-synaptic densities. These results suggest that smg p25A plays important roles in the regulation of synaptic functions such as exo-endocytotic recycling of synaptic vesicles during neurotransmitter release.

Cytoskeletal architecture of neuromuscular junction: localization of vinculin

Cytoskeletons underneath the postsynaptic membrane of neuromuscular junctions were studied by using a quick-freeze deep-etch method and immunoelectron microscopy of ultrathin frozen sections. In a quick-freeze deep-etched replica of fresh, unfixed muscles, 8.9 +/- 1.5-nm particles were present on the true postsynaptic membrane surface. Underneath this receptor-rich postsynaptic membrane, networks of fine filaments were observed. These cytoskeletal networks were more clearly observed in extracted samples. In these samples, diameters of the filaments which formed networks were measured. In the platinum replica, three kinds of filament were recognized--12 nm, 9 nm, and 7 nm in diameter. The 12-nm filament seemed to correspond to the intermediate filament. The other two filaments formed meshworks between intermediate filaments and plasma membrane. In ultrathin frozen sections vinculin label was localized just beneath the plasma membrane. Thirty-six percent of the label was within 18 nm from the cytoplasmic side of the plasma membrane and 50% was within 30 nm. Taking the size of the vinculin molecule into account, it was concluded that vinculin is localized just beneath the plasma membrane and might play some role in anchoring filaments which formed meshworks underneath the plasma membrane.