RESUMO
A new method for measuring fluoride ion released isopropyl methylphosphonofluoridate (sarin, GB) in the red blood cell fraction was developed that utilizes an autoinjector, a large-volume injector port (LVI), positive ion ammonia chemical ionization detection in the SIM mode, and a deuterated stable isotope internal standard. This method was applied to red blood cell (RBC) and plasma ethyl acetate extracts from spiked human and animal whole blood samples and from whole blood of minipigs, guinea pigs, and rats exposed by whole-body sarin inhalation. Evidence of nerve agent exposure was detected in plasma and red blood cells at low levels of exposure. The linear method range of quantitation was 10-1000 pg on-column with a detection limit of approximately 2-pg on-column. In the course of method development, several conditions were optimized for the LVI, including type of injector insert, injection volume, initial temperature, pressure, and flow rate. RBC fractions had advantages over the plasma with respect to assessing nerve agent exposure using the fluoride ion method especially in samples with low serum butyrylcholinesterase activity.
Assuntos
Substâncias para a Guerra Química/análise , Eritrócitos/química , Fluoretos/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Sarina/análise , Porco Miniatura , Animais , Substâncias para a Guerra Química/farmacocinética , Substâncias para a Guerra Química/intoxicação , Relação Dose-Resposta a Droga , Cobaias , Humanos , Exposição por Inalação , Troca Iônica , Marcação por Isótopo , Ratos , Ratos Sprague-Dawley , Sarina/farmacocinética , Sarina/intoxicação , Espectrometria de Massas por Ionização por Electrospray/instrumentação , Espectrometria de Massas por Ionização por Electrospray/métodos , SuínosRESUMO
Nearly 1 million infants and children are neglected and abused yearly in the United States, with a greater than 1% resulting mortality rate. One half of these children are seen by physicians for abuse-related injuries, and nearly 75% have injuries of the head and neck. Physicians, however, account for reporting only 11% of all cases. As experts trained in diseases and injuries of the head and neck, otolaryngologists are particularly well positioned to recognize abuse in the clinic and in the emergency room and during other consultations. We present an overview of child abuse definitions, risk factors, and legal obligations of the physician. We also review the manifestations of child abuse within the head and neck, with particular attention to the role of the otolaryngologist. We briefly discuss some conditions that may be mistaken for abuse and suggest a practical protocol for management of suspected cases in the clinic.
Assuntos
Maus-Tratos Infantis/diagnóstico , Otolaringologia , Papel do Médico , Criança , Maus-Tratos Infantis/estatística & dados numéricos , Abuso Sexual na Infância/diagnóstico , Humanos , Estados Unidos/epidemiologiaRESUMO
The lacrimal gland (LG) immunopathology of Sjögren's syndrome (SS) consists of a proliferation of B and CD4 lymphocytes surrounding epithelial structures (Pepose JS, et al: Ophthalmology 1990, 97:1599-1605). Based on the detection of EBV genomes in a greater percentage of SS than normal LG biopsies, we previously postulated that Epstein-Barr virus (EBV) is a risk factor for LG lymphoproliferation in SS (Pflugfelder SC, et al: Ophthalmology 1990, 97:976-984). The purpose of this study was to determine the cellular site(s) of infection, virus type, and antigen expression of EBV infecting normal and SS LGs. EBV DNA was detected by in situ hybridization in intraductal epithelia in 13-33% of lobules in 21% of normal LGs and in cells in areas of B lymphoproliferation as well as the majority of epithelia in 86% of SS LGs. EBV genomic sequences were amplified from 36% of normal and 88% of SS LG biopsies by polymerase chain reaction. Only type 1 EBV sequences were amplified in SS LGs; in contrast EBV nuclear antigen 2-deleted but not type 1 sequences were amplified in normal LGs. Immunohistochemistry with EBV-specific monoclonal antibodies was performed on normal and SS LGs. No EBV antigens were detected in normal LGs. In contrast, latent antigens (latent membrane protein, EBV nuclear antigen 2) were detected in lymphocytes in areas of B lymphoproliferation, and early and late lytic cycle antigens were observed in epithelia in SS LGs. These studies suggest that EBV may play a role in the LG B lymphoproliferation and epithelial pathologic changes observed in SS.
Assuntos
Infecções por Herpesviridae/patologia , Herpesvirus Humano 4/isolamento & purificação , Aparelho Lacrimal/patologia , Síndrome de Sjogren/microbiologia , Síndrome de Sjogren/patologia , Adulto , Idoso , Antígenos Virais/genética , Sequência de Bases , Cadáver , Proteínas de Ligação a DNA/genética , Antígenos Nucleares do Vírus Epstein-Barr , Herpesvirus Humano 4/imunologia , Humanos , Imuno-Histoquímica , Hibridização In Situ , Aparelho Lacrimal/microbiologia , Pessoa de Meia-Idade , Dados de Sequência Molecular , Reação em Cadeia da PolimeraseRESUMO
Members of the herpesvirus family, cytomegalovirus (CMV), Epstein-Barr virus (EBV), and herpes simplex virus (HSV), have been recognized as causal agents of chorioretinal inflammatory diseases. We investigated the use of the polymerase chain reaction for the detection of CMV, HSV, and EBV genomes in aqueous, subretinal fluid, and vitreous specimens in patients with clinically diagnosed CMV retinitis. Cytomegalovirus but not HSV or EBV genomic sequences were detected in all of these clinical specimens. We also investigated 18 normal aqueous and eight normal vitreous specimens obtained from patients undergoing cataract or vitrectomy surgery. Cytomegalovirus, HSV, and EBV DNA were not detected in any of the normal aqueous specimens. There was one weakly positive CMV normal vitreous, but none was HSV or EBV positive by the polymerase chain reaction. These results indicate that the polymerase chain reaction may be useful as a rapid and sensitive diagnostic technique to aid in the confirmation of clinical observations.
Assuntos
Humor Aquoso/microbiologia , DNA Viral/análise , Herpesviridae/isolamento & purificação , Reação em Cadeia da Polimerase , Corpo Vítreo/microbiologia , Síndrome da Imunodeficiência Adquirida/microbiologia , Anticorpos Antivirais/sangue , Autorradiografia , Citomegalovirus/genética , Citomegalovirus/isolamento & purificação , Infecções por Citomegalovirus/microbiologia , Herpesviridae/genética , Herpesvirus Humano 4/genética , Herpesvirus Humano 4/isolamento & purificação , Humanos , Reação em Cadeia da Polimerase/métodos , Retinite/microbiologia , Simplexvirus/genética , Simplexvirus/isolamento & purificaçãoAssuntos
Abrasão Química/efeitos adversos , Infecções por Herpesviridae/etiologia , Herpesvirus Humano 4/isolamento & purificação , Ceratite Dendrítica/etiologia , Aciclovir/uso terapêutico , Idoso , Antígenos Virais/sangue , Córnea/microbiologia , DNA Viral/análise , Feminino , Infecções por Herpesviridae/tratamento farmacológico , Herpesvirus Humano 4/efeitos dos fármacos , Humanos , Ceratite Dendrítica/tratamento farmacológico , Ceratite Dendrítica/microbiologia , Reação em Cadeia da Polimerase , Acuidade VisualRESUMO
Based on observations of primary Sjögren's syndrome (SS) following acute Epstein-Barr virus (EBV) infection, the authors hypothesized that EBV may play a role in the pathogenesis of SS. This hypothesis was tested by evaluating ten peripheral blood mononuclear (PBMN) cell specimens, ten lacrimal gland biopsies, and five tear specimens from 15 EBV-seropositive primary SS patients for EBV genomic sequences using polymerase chain reaction (PCR). Epstein-Barr virus DNA sequences were detected in 50% of SS PBMN cell specimens and 80% of SS lacrimal gland and tear specimens. In six SS patients, specimens were obtained from two or more sites (i.e., PBMN cell and lacrimal gland and/or tears), and EBV genomic sequences were amplified in the PBMN cells and the lacrimal gland or tears in three of these subjects. The authors previously detected EBV genomes in 32% (11/34) of normal human lacrimal glands from EBV-seropositive donors using PCR and concluded that the normal human lacrimal gland may be a site of EBV persistence; however, they were unable to amplify EBV sequences in DNA from PBMN cells or tear specimens from normal donors. Amplification of EBV DNA in PBMN cells, lacrimal glands, and tears of primary SS patients at a greater frequency (P less than 0.01) than normal controls suggests that EBV may be a risk factor in the pathogenesis of SS.
Assuntos
DNA Viral/isolamento & purificação , Herpesvirus Humano 4/isolamento & purificação , Aparelho Lacrimal/microbiologia , Neutrófilos/microbiologia , Síndrome de Sjogren/microbiologia , Lágrimas/microbiologia , Anticorpos/análise , Anticorpos/imunologia , Antígenos/análise , Antígenos/imunologia , Sequência de Bases , Linhagem Celular , Eletroforese em Gel de Ágar , Feminino , Amplificação de Genes , Humanos , Immunoblotting , Técnicas Imunoenzimáticas , Ativação Linfocitária/imunologia , Pessoa de Meia-Idade , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Síndrome de Sjogren/sangue , Síndrome de Sjogren/imunologiaRESUMO
Herpetic ocular disease is one of the major causes of corneal blindness. Clinical diagnosis of corneal disease is based principally on corneal appearance. However, abnormal morphology of the corneal epithelium (CE) is not an indicator for the presence of a herpes virus. Further, it has not been established if herpes viruses are present in normal corneal epithelial tissue. In these studies, the polymerase chain reaction was used to evaluate normal and diseased corneal epithelium for the presence of herpes simplex virus type 1 (HSV-1), Epstein-Barr virus (EBV) and cytomegalovirus (CMV) genomic sequences. Thirty-two normal corneal epithelium specimens obtained from cadavers shortly after death were analyzed for HSV-1, EBV and CMV genomic sequences. Three of the 32 normal CE specimens were positive for amplified EBV DNA, 1 was positive for HSV-1 DNA, and none was positive for CMV DNA. We also tested eight herpetic dendritic lesions of which 3 were HSV-1 culture and PCR positive. The remaining five dendritic lesions were HSV-1 culture and PCR negative. Since these lesions were not evaluated for other herpesviruses, the etiology of these dendritic lesions is unknown. Six corneal epithelium samples from HIV-infected donors were negative for EBV, CMV and HSV-1 amplified sequences. Positive EBV, CMV and HSV-1 serology on all normal donors and on donors with clinically apparent disease did not correlate with positive PCR results. The results of these studies suggest that EBV and HSV-1 DNA can be amplified from a small percentage of apparently normal corneal epithelium.
Assuntos
Córnea/microbiologia , DNA Viral/análise , Amplificação de Genes , Ceratite Dendrítica/microbiologia , Reação em Cadeia da Polimerase , Simplexvirus/isolamento & purificação , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antivirais/análise , Sequência de Bases , Southern Blotting , Citomegalovirus/genética , Citomegalovirus/isolamento & purificação , Epitélio/microbiologia , Feminino , Imunofluorescência , Herpesvirus Humano 4/genética , Herpesvirus Humano 4/isolamento & purificação , Humanos , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Sondas de Oligonucleotídeos , Valor Preditivo dos Testes , Simplexvirus/genéticaRESUMO
Epstein-Barr virus (EBV) has been implicated in several ocular diseases; however, detection of the EBV genome in ocular tissues has not been documented. We report the detection of amplified EBV genomic sequences in 11 of 26 normal lacrimal gland DNA samples by using the polymerase chain reaction. Serum was available for 19 of the lacrimal gland donors. All 19 were EBV seropositive, although of the 19 lacrimal gland-seropositive patients, EBV sequences were detected in only 10 of the samples. Further, amplified EBV sequences were not detected in circulating lymphocyte DNA from normal seropositive volunteers, most likely because of the low frequency of circulating EBV-infected B cells. Amplification of EBV from cadaver lacrimal gland DNA was possible with minute quantities of DNA, whereas peripheral blood mononuclear cell DNA from normal volunteers did not amplify EBV sequences. Interestingly, the peripheral blood mononuclear cell polymerase chain reactions contained approximately 100 times more DNA than the lacrimal gland polymerase chain reactions. We conclude that the lacrimal gland may be a site for EBV persistence and that positive EBV serology is not an indicator of which individuals may have EBV harbored within their lacrimal glands.
Assuntos
Herpesvirus Humano 4/isolamento & purificação , Aparelho Lacrimal/microbiologia , Sequência de Bases , Sondas de DNA , DNA Viral/genética , Desoxirribonuclease BamHI , Genes Virais , Herpesvirus Humano 4/genética , Humanos , Linfócitos/microbiologia , Dados de Sequência Molecular , Reação em Cadeia da PolimeraseRESUMO
CD21, the receptor for the C3d complement fragment, has been reported to be the Epstein-Barr virus (EBV) receptor in B lymphocytes and cultured squamous epithelial cells. This receptor has previously been found to be expressed in the epithelia of nonocular mucosal-associated lymphoid tissues (MALT) which are also sites of persistent EBV infection. We recently found evidence of persistent EBV infection in human ocular MALT and hypothesized that the epithelia in these tissues may also express the complement (C3d)/EBV receptor. To test this hypothesis, histologic sections of human lacrimal gland, ocular surface tissue (conjunctiva, limbus, and cornea), and conjunctival impression cytology specimens were stained by immunohistochemical techniques using three different anti-CD21 monoclonal antibodies (HB-5, B2, OKB7). HB-5 stained lacrimal gland ductal and all ocular surface epithelia, except limbus. B2 stained lacrimal gland ductal and limbal epithelia, and OKB7 stained only the limbal and corneal epithelia. The intensity of limbal and corneal epithelial staining with all anti-CD21 antibodies correlated with the level of epithelial differentiation, with the weakest staining noted in the cells which are thought to be the stem and transient amplifying cells of the cornea. These results suggest that external ocular tissues, similar to other MALT, have CD21-positive epithelia which may be potential targets for EBV infection.
Assuntos
Olho/metabolismo , Herpesvirus Humano 4/metabolismo , Aparelho Lacrimal/metabolismo , Receptores de Complemento/análise , Receptores Virais/análise , Anticorpos Monoclonais , Antígenos de Diferenciação de Linfócitos B/análise , Túnica Conjuntiva/metabolismo , Córnea/metabolismo , Epitélio/metabolismo , Imunofluorescência , Humanos , Técnicas Imunoenzimáticas , Aparelho Lacrimal/imunologia , Receptores de Complemento 3d , Esclera/metabolismoRESUMO
A monoclonal antibody, 1B3.1, was raised against a cloned IL-2-dependent T cell line that expresses the T gamma delta T cell receptor. MoAb 1B3.1 reacted with long-term cultured T cell lines of both T gamma delta and T alpha beta lineage, and with in vivo-stimulated T cells, derived from synovial fluid, but not with resting or short-term activated T cells, B cells, or macrophages. Immunoprecipitation of the 1B3.1 target antigens showed that 1B3.1 recognizes a 200/110 kDa molecule that is identical to the VLA-1 heterodimer precipitated by MoAb TS2/7. 1B3.1, however, binds to an epitope of VLA-1 that is distinct from the TS2/7 binding site. This new MoAb could be useful in further studies of the functions of VLA-1, and of the cells that express this molecule.
Assuntos
Anticorpos Monoclonais/imunologia , Antígenos de Diferenciação/imunologia , Antígenos de Superfície/imunologia , Linfócitos T/imunologia , Antígenos de Superfície/metabolismo , Moléculas de Adesão Celular , Epitopos , Citometria de Fluxo , Humanos , Testes de Precipitina , Receptores de Antígenos de Linfócitos T/análise , Receptores de Antígenos de Linfócitos T gama-delta , Receptores de Antígeno muito Tardio , Distribuição TecidualRESUMO
The tumor-associated antigen complex, TSP-180, was previously defined in carcinoma cell lines and found to be expressed in higher amounts in tumor than in normal tissue. Here, the mouse TSP-180 complex is shown to consist of three related proteins (bands 1, 2, and 3) associated with a distinct protein (band 5) that is probably derived from a precursor protein (band 4). All of these proteins are cell surface glycoproteins, and the largest protein (band 1) can be readily labeled with 32PO4. The mouse TSP-180 complex described here strongly resembles the recently described human integrin alpha 6-beta 4 complex. This homology was confirmed using two distinct rat anti-alpha 6 monoclonal antibodies, each of which recognized both human alpha 6-beta 4 and mouse TSP-180 complexes. Furthermore, the TSP-180 band 5 protein (mouse alpha 6) had an N-terminal sequence identical to that of human alpha 6. Finally, two different monoclonal antibodies are described, 346-11A and 439-9B, which directly recognize the multiple forms of mouse and human beta 4 proteins, respectively.
Assuntos
Antígenos de Neoplasias/genética , Antígenos de Superfície/genética , Genes , Glicoproteínas de Membrana/genética , Família Multigênica , Animais , Anticorpos Monoclonais , Complexo Antígeno-Anticorpo/análise , Antígenos de Neoplasias/isolamento & purificação , Antígenos de Superfície/isolamento & purificação , Western Blotting , Linhagem Celular , Eletroforese em Gel de Poliacrilamida , Epitopos/análise , Humanos , Integrina alfa6beta4 , Integrinas , Neoplasias Pulmonares/genética , CamundongosRESUMO
VLA-4 is a cell surface heterodimer in the integrin superfamily of adhesion receptors. Anti-VLA-4 antibodies inhibited cytolytic T cell activity, with inhibitory activity directed against the effector T cells rather than their targets. Thus, whereas other VLA receptors appear to mediate cell--matrix interactions, VLA-4 may have a cell--cell adhesion function. To facilitate comparative studies of VLA-4 and other integrins, cDNA clones for the human alpha 4 subunit of VLA-4 were selected and then sequenced. The 3805 bp sequence encoded for 999 amino acids, with an N-terminus identical to that previously obtained from direct sequencing of purified alpha 4 protein. The alpha 4 amino acid sequence was 17-24% similar to other integrin alpha chains with known sequences. Parts of the alpha 4 sequence most conserved in other alpha chains include (i) the positions of 19/24 cysteine residues, (ii) three potential divalent cation binding sites of the general structure DXDXDGXXD and (iii) the transmembrane region. However, alpha 4 stands apart from all other known integrin alpha subunit sequences because (i) alpha 4 has neither an inserted I-domain, nor a disulfide-linked C-terminal fragment, (ii) its sequence is the most unique and (iii) only alpha 4 has a potential protease cleavage site, near the middle of the coding region, which appears responsible for the characteristic 80,000 and 70,000 Mr fragments of alpha 4.
Assuntos
Antígenos de Diferenciação/genética , Glicoproteínas de Membrana/genética , Sequência de Aminoácidos , Antígenos de Superfície/genética , Sequência de Bases , Adesão Celular , Moléculas de Adesão Celular , DNA/genética , Humanos , Integrinas , Dados de Sequência Molecular , Conformação Proteica , Receptores Imunológicos/genética , Receptores de Antígeno muito Tardio , Homologia de Sequência do Ácido Nucleico , Linfócitos T Citotóxicos/imunologiaRESUMO
On platelets and other cell types, VLA-6 is a typical integrin heterodimer, with alpha 6-beta 1 subunit association. However, on colon carcinoma cell lines and other epithelial cells the alpha 6 subunit associates with a novel protein (called beta 4) rather than the VLA beta 1 subunit. The beta 4 protein differs from beta 1 because (i) it is not recognized by anti-beta 1 antibodies, (ii) it yields different V8 protease cleavage products, (iii) it has a more limited cell distribution, (iv) it has multiple forms, each larger in size than beta 1, and (v) it is susceptible to protease digestion which does not effect beta 1. Although different in many respects, the beta 4 subunit does have partial N-terminal sequence similarity to the already defined integrin beta 1, beta 2, and beta 3 subunits. The presence of alpha 6-beta 4 complexes was demonstrated by coprecipitation of beta 4 with an anti-alpha 6 antibody and by covalent cross-linking experiments. Although alpha 6-beta 4 complexes were present on certain cells, other VLA alpha subunits on those same cells remained associated with the VLA beta 1 subunit to form typical VLA heterodimers (e.g. VLA-1, VLA-2, VLA-3). By the criteria of N-terminal amino acid sequencing, antibody recognition, V8 peptide maps, and reduced/nonreduced gel migration, the alpha 6 subunit which associates with beta 4 appears identical to the alpha 6 associated with the VLA beta 1 subunit on platelets and other cell types. The beta 4 subunit may be of major importance because (i) it is highly abundant on the surface of colon carcinoma cell lines, and (ii) it is highly immunogenic relative to other surface proteins.
Assuntos
Antígenos de Diferenciação/metabolismo , Glicoproteínas de Membrana/metabolismo , Sequência de Aminoácidos , Anticorpos Monoclonais/imunologia , Carcinoma/metabolismo , Neoplasias do Colo/metabolismo , Epitélio/fisiologia , Humanos , Integrinas , Substâncias Macromoleculares , Dados de Sequência Molecular , Peptídeo Hidrolases/metabolismo , Mapeamento de Peptídeos , Testes de Precipitina , Receptores de Antígeno muito Tardio , Células Tumorais CultivadasRESUMO
The vertically transmitted Mtv-1 provirus is the primary causative factor of mammary neoplasia in certain C3Hf strains that lack the horizontally transmitted mouse mammary tumor virus (MMTV). The studies here report the molecular cloning of the germ line 4.5 kb Mtv-1 3' EcoRI fragment and sequencing of the 3' Mtv-1 LTR. The Mtv-1 LTR sequence is closely related to the 5' Mtv-11 LTR sequence also reported here, as well as to known Mtv-8 and MMTV LTR sequences in the portion of MMTV and Mtv-8 LTRs previously demonstrated to contain transcriptional regulatory sequences. A 91 bp unique sequence region, Mtv-1 bp 862 to 952, exists in the Mtv-1 LTR, which is upstream of the sequence homology with the MMTV transcriptional regulatory domain. The Mtv-1 unique sequence region is distinct from a 117 bp sequence, bp 862 to 978, in the Mtv-11 LTR sequence as well as reported Mtv-8 and MMTV LTR sequences, and is present in the germ line Mtv-1 5' and 3' LTR-containing restriction fragments. S1 nuclease mapping experiments of C3Hf/Se mammary tumor poly(A) RNA with the cloned Mtv-1 and Mtv-11 LTRs exhibited a specific set of S1 protected fragments demonstrating that Mtv transcripts which accumulate in C3Hf spontaneous mammary tumors are encoded by the Mtv-1 provirus.
Assuntos
DNA Viral/genética , Vírus do Tumor Mamário do Camundongo/genética , Provírus/genética , Animais , Sequência de Bases , Clonagem Molecular , Desoxirribonuclease EcoRI , Endonucleases , Camundongos , Camundongos Endogâmicos C3H , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Sequências Repetitivas de Ácido Nucleico , Mapeamento por Restrição , Homologia de Sequência do Ácido Nucleico , Endonucleases Específicas para DNA e RNA de Cadeia Simples , Transcrição GênicaRESUMO
After removal of very late antigen (VLA) 2 material from a radiolabeled detergent lysate of platelets, another VLA heterodimer was precipitated using antibody to the common VLA beta subunit. This structure was identified as VLA-5 because it contained VLA beta plus an alpha subunit that was (i) recognized by anti-alpha 5 antibodies and (ii) cleaved by V8 protease to yield a characteristic alpha 5-like pattern of peptide fragments. Besides VLA-2 and VLA-5, a third heterodimer, here named VLA-6, was also present on platelets. VLA-6 (an alpha 6 beta complex) was defined using the monoclonal antibody GoH3 (Sonnenberg, A., Janssen, H., Hogervorst, F., Calafat, J., and Hilgers, J. (1987) J. Biol. Chem. 262, 10376-10383). Although it resembled VLA-5 in size, VLA-6 was different from VLA-5 because (i) removal of the alpha 5 subunit did not remove alpha 6, (ii) removal of alpha 6 by the GoH3 antibody did not remove alpha 5, (iii) the alpha 5 and alpha 6 subunits had very distinct one-dimensional V8 peptide maps, and (iv) the alpha 6 and alpha 5 subunits had distinct migration patterns on two-dimensional O'Farrell gels. The beta subunit of VLA-6 was identified as the common VLA beta subunit because (i) it was recognized by anti-VLA beta antibody and (ii) it yielded a V8 protease cleavage map characteristic of beta. VLA-6 was not readily seen in anti-VLA beta immunoprecipitations, apparently because the alpha 6 subunit is only loosely or partially associated with the VLA beta subunit. Because VLA-5 and VLA-6 both closely resemble the previously defined Ic-IIa platelet protein complex, it is likely that there is more than one platelet "Ic" protein complexed with IIa.