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PURPOSE: Dedifferentiated low-grade osteosarcomas, which are considered high grade malignancies, can arise from the dedifferentiation of parosteal and low-grade osteosarcomas. Usually, localized dedifferentiated low-grade osteosarcomas are treated by wide resection, and the efficacy of adjuvant chemotherapy is controversial. We conducted a systematic review of studies that investigated the rates of mortality and significant events, such as recurrence and metastases, in localized dedifferentiated low-grade osteosarcoma patients who received wide resection only and in those who received wide resection and (neo-)adjuvant chemotherapy. METHODS: We identified 712 studies through systematic searches of Embase, PubMed, and the Cochrane Central Register of Controlled Trials databases. Of those studies, seven were included in this review and none were randomized controlled trials. In the seven studies, 114 localized dedifferentiated low-grade osteosarcoma patients were examined. RESULTS: Mortality rates of the resection plus chemotherapy (R + C) and the resection only (Ronly) groups were 20.3% and 11.4%, respectively [overall pooled odds ratio, 1.59 (P = 0.662); heterogeneity I2, 0%]. The local recurrence or distant metastasis rate in the R + C group was 36.7% and that in the Ronly group was 28.6% [overall pooled odds ratio, 1.37 (P = 0.484); heterogeneity I2 was 0%]. CONCLUSIONS: Results show a limited efficacy of adjuvant chemotherapy for localized dedifferentiated low-grade osteosarcoma. However, because this was a systematic review of retrospective studies that examined a small number of patients, future randomized controlled trials are needed.
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Purpose Immune cells such as cytotoxic T cells, helper T cells, B cells or tumor-associated macrophages (TAMs) contribute to the anti-tumor response or pro-tumorigenic effect in triple negative breast cancer (TNBC). The interrelation of TAMs, T and B tumor-infiltrating lymphocytes (TILs) in TNBC has not been fully elucidated. Methods We evaluated the association of tumor-associated macrophages, T and B TILs in TNBC. Results TNBCs with a high CD68+, CD163+ TAMs and low CD4+, CD8+, CD20+ TILs had a significantly shorter relapse-free survival (RFS) and overall survival (OS) than those with low CD68+, CD163+ TAMs and high CD4+, CD8+, CD20+ TILs. TNBCs with high CD68+ TAMs/low CD8+ TILs showed a significantly shorter RFS and OS and a significantly poorer prognosis than those with high CD68+ TAMs/high CD8+ TILs, low CD68+ TAMs/high CD8+ TILs, and low CD68+/low CD8+. TNBCs with high CD163+ TAMs/low CD8+, low CD20 + TILs showed a significantly shorter RFS and OS and a significantly poorer prognosis than those with high CD163+ TAMs/high CD8+ TILs and high CD163+ TAMs /high CD20+ TILs. Conclusions Our study suggests that TAMs further create an optimal tumor microenvironment (TME) for growth and invasion of cancer cells when evasion of immunoreactions due to T and B TILs occurs. In TNBCs, all these events combine to affect prognosis. The process of TME is highly complex in TNBCs and for an improved understanding, larger validation studies are necessary to confirm these findings (AU)
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Humanos , Femenino , Persona de Mediana Edad , Biomarcadores de Tumor/metabolismo , Linfocitos Infiltrantes de Tumor/inmunología , Neoplasias de la Mama Triple Negativas/inmunología , Macrófagos/inmunología , Estudios de Seguimiento , Estudios Retrospectivos , Análisis de Supervivencia , Neoplasias de la Mama Triple Negativas/metabolismo , Neoplasias de la Mama Triple Negativas/patología , PronósticoRESUMEN
A new cryogenic linear ion trap beamline has been constructed and commissioned, which serves to inject cold molecular and cluster ions into the RIKEN cryogenic electrostatic ring (RICE). Ions are created with an electrospray ion source, and a quadrupole mass filter is used for mass-selection prior to trap injection. The radio frequency octupole ion trap can be continuously loaded with ions and features a fast ion extraction mode to create short ion bunches with tens of µs duration. We report here on the simulations and development of the ion trap beamline and validate performance with the moderately heavy molecular cation methylene blue. Characterization of the novel trap design with additional wedge-shaped electrodes was carried out, which includes the determination of the temporal and spatial shape of the ion bunch and the total number of ions after extraction. Finally, these ion bunches are synchronized with the switching of a pulsed high-voltage acceleration device downstream of the trap, where the ions obtain a kinetic energy of up to 20 keV. The preparation and control of the keV ion beam are demonstrated for the ion injection into RICE.
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A new electrostatic ion storage ring, the RIKEN cryogenic electrostatic ring, has been commissioned with a 15-keV ion beam under cryogenic conditions. The ring was designed with a closed ion beam orbit of about 2.9 m, where the ion beam is guided entirely by electrostatic components. The vacuum chamber of the ring is cooled using a liquid-He-free cooling system to 4.2 K with a temperature difference of 0.4 K at most within all the positions measured by calibrated silicon diode sensors. The first cryogenic operation with a 15-keV Ne+ beam was successfully performed in August 2014. During the measurement, the Ne+ beam was stored under a ring temperature of 4.2 K with a residual-gas lifetime of more than 10 min. This permits an estimation of the residual gas density at a few 104 cm-3, which corresponds to a room-temperature-equivalent pressure of around 1×10-10 Pa. An effect of longitudinal pulse compression at the bunching cavity in the ring was clearly identified by monitoring the pick-up beam detector. The detailed design and mechanical structure of the storage ring, as well as the results from the commissioning run, are reported.
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BACKGROUND: Herlitz junctional epidermolysis bullosa (H-JEB) is an extremely rare genodermatosis characterized by lethality owing to severe blister formation. We report two unrelated Japanese patients with H-JEB. Genetic analyses detected a single nonsense mutation on the LAMC2 gene in these two patients. AIM: To identify the mutation involved and describe the first reported Japanese recurrent mutation in the LAMC2 gene. METHODS: Direct sequencing was performed of DNA from either peripheral blood or fetal cells in amniotic fluid. Reverse transcriptase PCR was used to confirm that an aberrant transcript resulted from the splice site mutation. A haplotype analysis was performed to define the origin of the recurrent mutation. RESULTS: Both patients had blisters and erosions on the trunk and limbs at birth, with nail dystrophy. Patient 1 died as a result of sepsis at 30 weeks of age, and patient 2 died as a result of disseminated intravascular coagulation at 20 weeks of age. Mutation analysis of the LAMC2 gene revealed that patient 1 was compound heterozygous for a nonsense mutation (p.Cys553X) and a novel splice site mutation (c.2868+1delG), and patient 2 was a homozygous for p.Cys553X. Prenatal diagnosis performed during a subsequent pregnancy in family 2 revealed that this second child was heterozygous for p.Cys553X, and was thus not affected. Haplotype analysis suggested that a p.Cys553X allele derived from the same origin had been independently inherited by these two unrelated families. CONCLUSIONS: p.Cys553X in the LAMC2 gene may be a Japanese-specific recurrent mutation as a result of a founder effect, and it may therefore be useful for initial screening in the mutation analysis of H-JEB.
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Codón sin Sentido/genética , Análisis Mutacional de ADN/métodos , Epidermólisis Ampollosa de la Unión/genética , Laminina/genética , Pueblo Asiatico/genética , Epidermólisis Ampollosa de la Unión/fisiopatología , Resultado Fatal , Femenino , Haplotipos , Humanos , Lactante , Masculino , Linaje , Embarazo , Diagnóstico PrenatalRESUMEN
We report a Japanese infant who had a novel de novo splice-site mutation in the COL7A1 gene, which resulted in in-frame exon 87 skipping. Very interestingly, most of the previously reported cases with the same exon skipping presented as dystrophic epidermolysis bullosa (DEB) pruriginosa. The proband in this study showed an extremely mild clinical phenotype, with no nail dystrophy, pruritus or prurigo-like lesions. However, dominant (DDEB) pruriginosa often shows a typical mild DEB phenotype until the onset of pruritus, making it likely that as she gets older the proband will present with features consistent with DDEB pruriginosa. By knowing in advance the anticipated clinical course, it might be possible to reduce or even prevent development of nodular prurigo-like lesions by sufficient control of pruritus. Our study should contribute to further refinement of the genotype-phenotype correlations in DEB, emphasizing the significance of mutation analysis for correct diagnosis and possibly for prediction of prognosis.
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Epidermólisis Ampollosa Distrófica/patología , Prurigo/patología , Análisis Mutacional de ADN , ADN Recombinante/genética , Epidermólisis Ampollosa Distrófica/genética , Exones , Femenino , Humanos , Lactante , Fenotipo , Prurigo/genéticaRESUMEN
OBJECTIVE: To investigate whether FK506 (tacrolimus) can inhibit Fas- or A23187-induced interleukin (IL)-8 expression and cell death in A549 human alveolar epithelial cells, plus Fas-mediated acute lung injury in vivo. METHODS: Assays for IL-8, cell death, and caspase-3 activity were performed. A549 cells were treated with 25 micromol A23187 or 0.2 microg/ml agonistic anti-Fas antibody plus 5 ng/ml interferon-gamma (IFN-gamma). Tacrolimus was treated at 0.1-10 ng/ml. For in vivo experiment, agonistic anti-Fas antibody (Jo2) at 2.5 microg/g was intratracheally instilled into C57BL/6 mice. Neutrophils and protein contents in bronchoalveolar lavage (BAL) fluid were measured within 24 h of instillation. Mice were orally treated with 32 mg/kg of tacrolimus 24 h and 1 h prior to instillation. RESULTS: Both Fas and A23187 caused significant IL-8 expression and cell death in A549 cells. Tacrolimus inhibited A23187-induced IL-8 expression alone while it protected all Fas-mediated responses. Mice instilled intratracheally with Jo2 at 2.5 microg/g had significant increases in neutrophils, protein contents in BAL fluid and in expression of chemoattractants for neutrophils. These increases were reversed by tacrolimus. CONCLUSIONS: Tacrolimus serves as a therapeutic option for improving lung injury through inhibition of Fas-mediated inflammation.
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Inmunosupresores/farmacología , Neumonía/patología , Mucosa Respiratoria/efectos de los fármacos , Mucosa Respiratoria/patología , Tacrolimus/farmacología , Receptor fas/antagonistas & inhibidores , Animales , Anticuerpos Monoclonales/farmacología , Calcimicina/farmacología , Caspasa 3/genética , Caspasa 3/metabolismo , Muerte Celular/efectos de los fármacos , Línea Celular , Relación Dosis-Respuesta a Droga , Regulación de la Expresión Génica/efectos de los fármacos , Regulación Enzimológica de la Expresión Génica , Humanos , Inflamación/tratamiento farmacológico , Interleucina-8/genética , Interleucina-8/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Neumonía/etiología , Neumonía/metabolismo , Alveolos Pulmonares/citología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Mucosa Respiratoria/lesiones , Mucosa Respiratoria/metabolismo , Receptor fas/fisiologíaRESUMEN
Adherens junctions (AJs) are cell-cell and cell-matrix junctions that are known to comprise the transmembrane and cytoplasmic components linked to the f-actin cytoskeleton. Although the presence of AJs han been confirmed in normal human epidermis, previous studies immunolocalizing AJ-related antigens have been controversial. The purpose of this study was to produce a more precise molecular mapping of AJs and their constituents in relation to desmosomes in normal human epidermal keratinocytes. Using an electron microscope (EM) method to optimally fix plasma membranes. AJ structures were typically seen as a narrowing of the intercellular space between two keratinocytes that was distinct from desmosomes and gap junctions. Such structures were consistently found more frequently in the upper epidermis than in the basal layer. Immunogold electron microscopy showed an absence of the AJ components (E-cadherin and beta-catenin) from desmosomal areas but they were present at interdesmosomal areas at sites of close membrane association. Conversely, the desmosomal components plakoglobin and plakophilin 1 were restricted only to the outer attachment plaque of the desmosome. These results further confirm that AJs have a distinct molecular composition and distribution from desmosomes and that they regularly occur between desmosomes along the keratinocyte plasma membrane to provide alternative cell-cell adhesion mechanisms.
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Uniones Adherentes/fisiología , Desmosomas/metabolismo , Epidermis/fisiología , Actinas/química , Actinas/metabolismo , Antígenos/química , Cadherinas/metabolismo , Adhesión Celular , Membrana Celular/metabolismo , Proteínas del Citoesqueleto/metabolismo , Citoesqueleto/metabolismo , Epidermis/metabolismo , Epidermis/ultraestructura , Técnica del Anticuerpo Fluorescente Indirecta , Congelación , Humanos , Inmunohistoquímica , Queratinocitos/metabolismo , Microscopía Electrónica , Microscopía Fluorescente , Microscopía Inmunoelectrónica , Tetróxido de Osmio/farmacología , Unión Proteica , Piel/metabolismo , Transactivadores/metabolismo , beta CateninaRESUMEN
We have newly synthesized osteotropic diclofenac with bisphosphonic moiety (DIC-BP) based on the concept of Osteotropic Drug Delivery System (ODDS) and investigated its potency of site-specific and controlled delivery of diclofenac to the bone in rats. After intravenous injection into rats, DIC-BP was predominantly distributed in the skeleton. DIC-BP once incorporated in the bone was gradually eliminated (t(1/2)=9.7 days), releasing diclofenac into the bone compartment. As a result, the bone concentration of regenerated diclofenac was apparently constant over 28 days. Furthermore, we evaluated the anti-inflammatory effects of DIC-BP compared with diclofenac (sodium salt) in adjuvant-induced arthritic rats. The mean effective doses (ED(50)) were 0.55 mg/kg and 1.3 mg/kg for daily oral administration of diclofenac and weekly intravenous injection of DIC-BP, respectively. Considering the frequency of medication of 17 times for diclofenac and 4 times for DIC-BP in the experimental period, ED(50) was corrected to 9.4 and 5.2 mg/kg (per experimental period) for diclofenac and DIC-BP, respectively. Moreover, DIC-BP exhibited no side effects of gastrointestinal damage, typical of non-steroidal anti-inflammatory drugs. Thus, ODDS of diclofenac shows promise as an approach for highly potent and non-toxic therapy of diclofenac, with less frequent medication.
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Antiinflamatorios no Esteroideos/administración & dosificación , Huesos/metabolismo , Diclofenaco/administración & dosificación , Difosfonatos/administración & dosificación , Sistemas de Liberación de Medicamentos , Profármacos/administración & dosificación , Animales , Artritis Experimental/tratamiento farmacológico , Diclofenaco/farmacocinética , Femenino , Fémur/metabolismo , Inyecciones Intravenosas , Ratas , Ratas Sprague-DawleyRESUMEN
The 180 kDa bullous pemphigoid antigen is a hemidesmosome-associated transmembranous protein with a molecule length estimated to be 190-230 nm, which is much longer than the transverse length of the lamina lucida and lamina densa. The purpose of this study was to clarify the precise in vivo structure of the 180 kDa bullous pemphigoid antigen in normal human skin. We used three monoclonal antibodies directed to (i) the intracellular globular head of the 180 kDa bullous pemphigoid antigen, (ii) the mid-portion of the flexible tail of the antigen, corresponding approximately to amino acids 1000-1320, and (iii) the carboxyl terminal end, corresponding approximately to amino acids 1320-1500 of the antigen. Using low temperature postembedding immunoelectron microscopy, we quantitated the distribution of immunogold labeling of these monoclonal antibodies in normal human skin. The results showed that the monoclonal antibodies (i) bound to the intracellular portion of the hemidesmosome at a mean distance of 20 nm from the plasma membrane, (ii) bound to the lamina densa beneath the hemidesmosome at a mean distance of 65 nm from the plasma membrane, and (iii) bound to the lamina densa-lamina lucida interface at a mean distance of 39 nm from the plasma membrane. Considering the reported size of the 180 kDa bullous pemphigoid antigen, our results indicate that the extracellular domain of the antigen has at least one loop structure in the lamina densa in vivo. This unique structure of the antigen is thought to contribute to dermo- epidermal adhesion by intertwining with other basement membrane components.
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Autoantígenos/química , Secuencia de Aminoácidos , Animales , Proteínas Portadoras , Proteínas del Citoesqueleto , Distonina , Espacio Extracelular/química , Hemidesmosomas/química , Humanos , Laminina/análisis , Ratones , Proteínas del Tejido Nervioso , Colágenos no Fibrilares , Estructura Terciaria de Proteína/fisiología , Colágeno Tipo XVIIAsunto(s)
Epidermólisis Ampollosa de la Unión/genética , Queratinocitos/metabolismo , Laminina/genética , Piel/metabolismo , Línea Celular Transformada , Colágeno/análisis , ADN Complementario/genética , Vectores Genéticos , Humanos , Inmunohistoquímica , Laminina/química , Laminina/metabolismo , Proteínas Recombinantes/genética , Virus 40 de los Simios , TransfecciónRESUMEN
Dystrophic epidermolysis bullosa (DEB), caused by mutations in the gene encoding type VII collagen (COL7A1), is known to show heterogeneous clinical phenotypes. Certain correlations between the nature or position of COL7A1 mutations and the resultant DEB phenotypes have been suggested, although such relationships may be more complex than initially thought. The purpose of the present study was to clarify the molecular basis of two different subtypes of dominant DEB (DDEB), EB pruriginosa and classical type. Interestingly, we found that both cases were caused by a missense glycine substitution mutation by different amino acids in the same codon of COL7A1 (G2028R and G2028A). These results further support the notion that different glycine substitution mutations in the same codon can lead to heterogeneous clinical phenotypes of DDEB, EB pruriginosa and classical type.
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Colágeno/genética , Epidermólisis Ampollosa Distrófica/genética , Adulto , Sustitución de Aminoácidos , Niño , Codón , Colágeno/análisis , Femenino , Glicina/genética , Humanos , Mutación , Linaje , FenotipoRESUMEN
Plectin, a widespread cytoskeletal linker protein, is prominently expressed in basal keratinocytes of the epidermis. HD1, originally identified as a hemidesmosomal protein, has been suggested to be an isoform of or closely related to plectin, but the exact relationship between these proteins is unknown. Plectin has recently been identified as the gene/protein system at fault in epidermolysis bullosa simplex associated with muscular dystrophy (EBS-MD; OMIM# 226670). In this study, we examined the expression patterns of plectin and HD1 epitopes in the skin of four unrelated patients with EBS-MD confirmed to be caused by plectin gene mutations. By indirect immunofluorescence, all monoclonal antibodies (mAbs) to plectin (5B3, 10F6) or to HD1 (121, E2, K15, 156) bound to the epidermal basement membrane zone (BMZ) of normal human skin. In addition, immunostaining along the periphery of keratinocytes was detected with mAbs 5B3, 10F6 (antiplectin), K15 and 156 (anti-HD1), but not with mAbs 121 and E2 (anti-HD1). Immunolabeling for mAbs 5B3 and 10F6 (antiplectin) was absent in the skin of three patients who had premature termination codon mutations in the plectin gene in both alleles. In contrast, labeling was only slightly reduced in a patient who was homozygous for a 9-bp in-frame deletion mutation in the same gene. Interestingly, peripheral labeling of keratinocytes using mAbs K15 and 156 (anti-HD1) was clearly present in all the patients despite the disappearance of BMZ labeling. Quantitative analysis by postembedding immunoelectron microscopy demonstrated that both plectin and HD1 epitopes were localized in the inner plaque of hemidesmosomes with a mean distance of 110 and 120 nm from the plasma membrane, respectively. These results confirm the molecular heterogeneity of EBS-MD in terms of the expression patterns of plectin and HD1 epitopes which correlate with clinical severity, the pattern of plectin gene mutations and their consequences.
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Epidermólisis Ampollosa Simple/complicaciones , Epidermólisis Ampollosa Simple/metabolismo , Epítopos/metabolismo , Proteínas de Filamentos Intermediarios/inmunología , Proteínas de Filamentos Intermediarios/metabolismo , Distrofias Musculares/complicaciones , Adulto , Membrana Basal/metabolismo , Membrana Basal/patología , Niño , Epidermólisis Ampollosa Simple/patología , Femenino , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Masculino , Microscopía Inmunoelectrónica , Persona de Mediana Edad , Plectina , Piel/metabolismo , Piel/patologíaRESUMEN
In vitro release behavior and cytotoxic activity, and in vivo plasma disposition of newly synthesized macromolecular derivatives of cisplatin (CDDP) were investigated and compared with CDDP. The derivatives included oxidized dextran conjugate of CDDP (OX-Dex/CDDP) and dicarboxymethylated dextran conjugate of CDDP (DCM-Dex/CDDP). In vitro release of platinum complex from dextran conjugated CDDP was determined by an equilibrium dialysis method. These dextran conjugates showed sustained release of the platinum complex. In vitro release half-life for DCM-Dex/CDDP was significantly longer (4.5 times) than that for OX-Dex/CDDP. In vitro cytotoxic activity of CDDP and dextran conjugated CDDP against colon 26, mouse colon cancer cell line, was measured using the MTT assay method. OX-Dex/CDDP showed a similar cytotoxic activity to CDDP. However, both cytotoxic activities were markedly decreased when preincubated with the medium containing serum. On the other hand, DCM-Dex/CDDP retained residual cytotoxic activity at a significantly higher level than OX-Dex/CDDP after preincubation with the medium containing serum, although it showed the lowest cytotoxic activity. This indicated longer maintenance of the in vitro antitumor activity of DCM-Dex/CDDP in serum compared with OX-Dex/CDDP. Plasma disposition of CDDP and dextran conjugated CDDP was determined by intravenous administration to rats. Although the total platinum plasma concentration-time profile for OX-Dex/CDDP was similar to that for CDDP, its markedly higher profile was achieved when DCM-Dex/CDDP was administered. The values of the total platinum AUC and MRT, where AUC is the area under the platinum concentration-time curve and MRT is the mean residence time, for DCM-Dex/CDDP were 11.2 times and 4.8 times significantly higher than with OX-Dex/CDDP in plasma, respectively. DCM-Dex/CDDP also showed a significantly lower total clearance compared with OX-Dex/CDDP. These results from the in vivo experiments revealed that retention of DCM-Dex/CDDP in blood circulation was much greater than that for OX-Dex/CDDP. DCM-Dex/CDDP thus has potential as a macromolecular derivative of CDDP for passive tumor targeting.
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Antineoplásicos/farmacocinética , Cisplatino/farmacocinética , Dextranos/farmacocinética , Animales , Antineoplásicos/sangre , Antineoplásicos/farmacología , Secuencia de Carbohidratos , División Celular/efectos de los fármacos , Cisplatino/sangre , Cisplatino/farmacología , Masculino , Ratones , Datos de Secuencia Molecular , Oxidación-Reducción , Ratas , Ratas Wistar , Factores de Tiempo , Células Tumorales CultivadasRESUMEN
Cryoultramicrotomy was originally established to provide ultrathin cryosections as substrates for on-section immunolabeling in immunoelectron microscopy. Recently, we recognized that ultrathin cryosections of skin (0.2 micrometer thick) could serve as substrates for immunofluorescence (IF) with excellent resolution. To assess the advantages and the limitations of IF on ultrathin cryosections, we compared the labeling of IF on 0.2-micrometer ultrathin cryosections of skin with those of routine IF on 6-micrometer cryostat sections, confocal laser scanning microscopy (LSM), and immunogold electron microscopy using several markers of keratinocyte cell surface and basement membrane zone molecules. IF on ultrathin cryosections clearly demonstrated a lack of bullous pemphigoid antigens beneath the melanocytes, desmosomal antigens as discontinuous dot-like labeling, and nondesmosomal plasma membrane antigen as a ladder-like pattern. IF on ultrathin cryosections provided convincing images with higher resolution than confocal LSM, which corresponded well to those of immunogold electron microscopy. IF on ultrathin cryosections had superior resolution compared to routine IF or confocal LSM and should serve as a powerful tool in future studies for the analysis of skin antigens. (J Histochem Cytochem 46:1455-1460, 1998)
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Proteínas Portadoras , Técnica del Anticuerpo Fluorescente , Secciones por Congelación , Proteínas de la Membrana/metabolismo , Microtomía , Proteínas del Tejido Nervioso , Colágenos no Fibrilares , Piel/metabolismo , Antígenos CD/metabolismo , Autoantígenos/metabolismo , Cadherinas/metabolismo , Colágeno/metabolismo , Proteínas del Citoesqueleto/metabolismo , Desmogleína 1 , Desmogleína 3 , Desmoplaquinas , Distonina , Humanos , Inmunohistoquímica , Integrina alfa6 , Microscopía Confocal , Microscopía Electrónica , Proteínas de Neoplasias/metabolismo , Colágeno Tipo XVIIRESUMEN
Bullous pemphigoid (BP) is a blistering skin disease in which the patient develops autoantibodies to the epidermal basement membrane zone. Using postembedding immunogold electron microscopy, we previously demonstrated that autoantibodies against the 230-kDa BP antigen (BPAG1) bind to the intracellular hemidesmosomal component of normal skin, whereas those against the 180-kDa BP antigen (BPAG2) bind only along the plasma membrane of hemidesmosomes. The purpose of the present study was to elucidate the precise localization of the in vivo deposited IgG antibodies in fresh perilesional skin of patients with BP. Samples of fresh perilesional skin were obtained from three patients with BP whose sera reacted only with BPAG1, only with BPAG2, and with both BPAG1 and BPAG2 upon immunoblotting using epidermal extracts. Cryofixed and cryosubstituted skin samples were used as a substrate for on-surface immunolabelling. In all three cases, most of the gold particles were observed close to the plasma membrane of the basal keratinocytes. A quantitative analysis revealed that most (> 80%) of the in vivo deposited IgG antibodies in the three cases were localized within 10 nm inside to 50 nm outside of the cell membrane, with a single peak observed 0-10 nm outside of the cells (> 50%). This distribution corresponded to the location of BPAG2, but not to that of BPAG1. These findings suggest that most, if not all, of the in vivo deposited IgG antibodies in the perilesional skin of BP are directed against BPAG2, rather than against BPAG1, thus further supporting the crucial role of anti-BPAG2 autoantibody in the initial stage of blister formation in BP.
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Proteínas Portadoras , Colágeno , Proteínas del Citoesqueleto , Inmunoglobulina G/análisis , Proteínas del Tejido Nervioso , Colágenos no Fibrilares , Penfigoide Ampolloso/inmunología , Piel/inmunología , Autoantígenos/inmunología , Membrana Celular/inmunología , Distonina , Humanos , Queratinocitos/inmunología , Microscopía Electrónica , Piel/ultraestructura , Colágeno Tipo XVIIRESUMEN
Recent technical advances in immunoelectron microscopy (IEM), including methods of pre- and postembedding IEM and cryoultramicrotomy, have helped to elucidate the precise ultrastructural localization of various basement membrane-related molecules. Our objective was to evaluate the advantages and disadvantages of several different techniques for studying the ultrastructural organization of basement membrane components. We found that, while "on-surface" immunolabeling of postembedding IEM and cryoultramicrotomy with anti-type IV collagen or anti-laminin-5 antibody clearly demonstrated dense labeling on the lamina densa, preembedding IEM with a 1-nm ultra-small gold probe showed labeling only on the epidermal and/or dermal surfaces of the lamina densa, with no specific gold particles being seen within the lamina densa itself. These results indicate that even ultra-small colloidal gold-labeled antibody fails to penetrate the lamina densa in preembedding IEM. However, labeling with a GB3 monoclonal antibody against laminin-5 was demonstrable with preembedding IEM and cryoultramicrotomy, but not with postembedding IEM, probably due to a loss of antigenicity. These results confirm the advantages and limitations of these techniques of IEM and emphasize the importance of using different techniques of IEM in determining the precise ultrastructural distribution of basement membrane antigens.
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Antígenos/ultraestructura , Moléculas de Adhesión Celular/ultraestructura , Colágeno/ultraestructura , Proteínas de la Membrana/ultraestructura , Microscopía Inmunoelectrónica/métodos , Membrana Basal/ultraestructura , Microscopía por Crioelectrón/métodos , Femenino , Técnica del Anticuerpo Fluorescente , Oro Coloide/inmunología , Humanos , Masculino , Piel/ultraestructura , KalininaRESUMEN
Linear IgA bullous dermatosis is an autoimmune blistering disease characterized by circulating IgA anti-basement membrane autoantibodies. A 97 kDa protein (97-LAD), which localizes at the basement membrane zone of normal human skin, is one of the major autoantigens associated with this disease and possesses multiple regions of amino acid identity with the extracellular domain of the 180 kDa bullous pemphigoid antigen, BPAG2. To investigate further the relationship between 97-LAD and BPAG2, immunogold electron microscopy was performed on cryo-ultrathin sections of normal human skin using a series of polyclonal and monoclonal antibodies. Gold particles immunolabeling two newly developed monoclonal antibodies against 97-LAD were localized to the lamina lucida. This immunolabeling pattern was associated with hemidesmosomes and localized at a mean distance of 28 nm beneath the plasma membrane of basal keratinocytes. In contrast, polyclonal antibodies against a fusion protein containing the NC16A domain of BPAG2 immunolabeled the plasma membrane of the hemidesmosomal complex, whereas polyclonal antibodies against the carboxyl terminus mainly immunolabeled the lower lamina lucida with a mean distance of 42 nm beneath the plasma membrane. By double immunolabeling, 97-LAD was localized as if being sandwiched between the NC16A and the carboxyl terminal domains of BPAG2. These results clearly demonstrated the co-localization of 97-LAD and the extracellular portion of BPAG2 in the lamina lucida, and suggested that 97-LAD is closely related to, and/or forms a complex with, the extracellular domain of BPAG2.