RESUMO
Duchenne Muscular Dystrophy (DMD) and its murine model, mdx, are characterized by Ca(2+) induced muscle damage and muscle weakness followed by distorted dentofacial morphology. In both, DMD patients and in mdx mice, could be proven so far that only the extraocular muscles (EOM) are not affected by muscular dystrophy. The EOMs are protected against calcium overload by enhanced expression of genes involved in the Ca(2+) homeostasis. We could recently demonstrate that masticatory muscles of mdx mice are differentially affected by muscle dystrophy. The dystrophic masseter and temporalis shows muscle histology comparable to all other skeletal muscles in this animal model, whereas dystrophic tongue muscles seem to develop a milder phenotype. Due to this fact it is to hypothesize that an altered Ca(2+) homeostasis seems to underlie the mdx masticatory muscle pathology. Aim of this study was to examine the mRNA and protein levels of the sarcoplasmic reticulum Ca(2+) ATPases SERCA1 and SERCA2, the plasma membrane Ca(2+) ATPases Atp2b1 and Atp2b4, the sodium/calcium exchanger NCX1, the ryanodine receptor 1, parvalbumin, sarcolipin, phospholamban and the L-type Ca(2+) channel alpha-1 subunit (Cacna1s) in Musculus masseter, temporalis, and tongue of 100 day old control and mdx mice. In mdx masseter muscle significant increased mRNA levels of NCX1 and Cacna1s were found compared to control mice. In contrast, the mRNA amount of RYR1 was significant reduced in mdx temporalis muscle, whereas ATP2b4 was significant increased. In mdx tongue a down-regulation of the ATP2b1, sarcolipin and parvalbumin mRNA expression was found, whereas the phospholamban mRNA level was significantly increased compared to controls. These data were verified by western blot analyses. Our findings revealed that mdx masticatory muscles showed an unequally altered expression of genes involved in the Ca(2+) homeostasis that can support the differences in masticatory muscles response to dystrophin deficiency.
Assuntos
Cálcio/metabolismo , Expressão Gênica , Músculos da Mastigação/metabolismo , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/metabolismo , Animais , Canais de Cálcio Tipo L/genética , Feminino , Homeostase , Masculino , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos mdx , Proteínas Musculares/genética , Parvalbuminas/genética , Parvalbuminas/metabolismo , ATPases Transportadoras de Cálcio da Membrana Plasmática/genética , Proteolipídeos/genética , RNA Mensageiro/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/genética , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/genética , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Trocador de Sódio e Cálcio/genética , Trocador de Sódio e Cálcio/metabolismoRESUMO
BACKGROUND: Remote Patient Management for chronic heart failure (CHF) is gaining increasing importance in health care. Telemonitoring is defined as daily measuring of health parameters by the patient and their transmission to a telemedical centre. The adherence of this action by the patient can be considered as a measure for RPM adoption. METHODS: The randomized controlled clinical trial TIM-HF (NCT 00543881) was conducted between 2008 and 2010 with 710 CHF patients with the primary endpoint total mortality for a mean follow-up of 21.5 ± 7.2 months. The non-prespecified analysis of adherence to daily measuring of ECG, blood pressure, weight and self-assessment was focused on sociodemographic and disease-related factors of the 354 RPM patients. RESULTS: The mean adherence to telemonitoring was more than 80% (absolute adherence: 81.8 ± 22.8%, relative adherence: 88.9 ± 21.5%). From the beginning of treatment 6.5% of the patients (23/354) have shown an adherence below average. The high adherence of the majority of the patients was stable for the entire study duration and irrespective of age, sex, severity of the disease and the presence of mild to moderate depression. CONCLUSION: A high adherence can be achieved by individual training of the patient regarding the handling of his disease, the use of telemedical devices and an easy-to-use telemonitoring system. The majority of the informed self-determined CHF patients NYHA class II/III are adopting telemonitoring and are adherent in the long term.
Assuntos
Insuficiência Cardíaca/epidemiologia , Insuficiência Cardíaca/terapia , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Consulta Remota/estatística & dados numéricos , Telemetria/estatística & dados numéricos , Idoso , Monitorização Ambulatorial da Pressão Arterial/psicologia , Peso Corporal , Eletrocardiografia , Feminino , Alemanha , Insuficiência Cardíaca/psicologia , Humanos , Masculino , Aceitação pelo Paciente de Cuidados de Saúde/psicologia , Cooperação do Paciente/psicologia , Cooperação do Paciente/estatística & dados numéricos , Pacientes Desistentes do Tratamento/estatística & dados numéricos , Telemetria/psicologia , Revisão da Utilização de Recursos de Saúde/estatística & dados numéricosRESUMO
INTRODUCTION: Calcifying pseudoneoplasms of the neuraxis (CAPNON) are rare, slow-growing lesions occurring anywhere in the central nervous system (CNS). Since their first description in 1978, only 39 cases have been reported in the literature. METHODS: The cases of two patients with histopathologically verified diagnoses of CAPNON are presented. Thereafter, we review all reports published so far with respect to study type, number of patients, anatomical area (intracranial, spinal, or both), clinical presentation, radiological presentation, therapy, duration of follow-up, incidence and type of complication, and outcome. Furthermore, current recommendations for the management of spinal and cerebral CAPNON are discussed. RESULTS: A total of 19 retrospective articles were identified and selected for review: 6 case series (31.6 %) and 13 reports of single cases (68.4 %). The 19 articles and our two additional cases added up to a total of 19 patients with spinal CAPNON and 22 patients with intracranial CAPNON. All patients were treated surgically. A follow-up was provided in 13 patients with spinal (68.4 %) and in 16 patients with intracranial CAPNON (72.7 %), respectively. The follow-up showed no signs of recurrence in 12 of 13 patients with spinal CAPNON (92.3 %) and in 15 of 16 patients with intracranial CAPNON (93.7 %). One-tailed Fisher's exact test revealed no significant difference between complete and incomplete resection in terms of disease recurrence (spinal: p = 0.6842; intracranial: p = 0.3749). Analysis of the literature did not reveal any deaths directly associated with CAPNON. CONCLUSIONS: Calcifying pseudoneoplasms are rare benign lesions of the CNS of yet unknown origin. Because of the increasing number of reports, this clinical entity should be taken into consideration in the differential diagnosis of intracranial and intraspinal calcified lesions.
Assuntos
Encefalopatias/diagnóstico , Encefalopatias/terapia , Calcinose/diagnóstico , Calcinose/terapia , Encefalopatias/epidemiologia , Calcinose/epidemiologia , Intervalo Livre de Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do TratamentoRESUMO
Meningiomas are common intracranial tumours that arise from arachnoidal cells. Clinically they often manifest by headache, focal or generalized seizures, or neurologic deficits as a result of brain compression. More than 90 percent of these mostly slow growing meningiomas are benign. In symptomatic patients a resection should be performed with the intention to cure or at least alleviate symptoms. In cases of subtotal resection an adjuvant radiotherapy should be deliberated. Stereotactic radiotherapy as initial treatment is an effective alternative for meningiomas, especially in patients not suitable for surgery due to various reasons. In patients that are refractory to treatment or with unresectable disease a hormonal- or chemotherapy can be considered.
Assuntos
Neoplasias Meníngeas/terapia , Algoritmos , Encéfalo/patologia , Terapia Combinada , Irradiação Craniana , Craniotomia , Estudos Transversais , Humanos , Imageamento por Ressonância Magnética , Neoplasias Meníngeas/diagnóstico , Neoplasias Meníngeas/epidemiologia , Prognóstico , Radiocirurgia , Radioterapia Adjuvante , Tomografia Computadorizada por Raios XRESUMO
Titanium (Ti) is an established biomaterial for bone replacement. However, facilitation of osteoblast attachment by surface modification with chemical groups could improve the implant performance. Therefore, this study aimed to evaluate the effect of a plasma polymerized allylamine (PPAAm) layer on the local inflammation in a rat model. Three series (RM76AB, RM78AB, RM77AB) of PPAAm-treated Ti plates were prepared using different plasma conditions. Twelve male LEW.1A rats received one plate of each series and one uncoated control plate implanted into the back musculature. After 7, 14 and 56 days, four rats were euthanized to remove the implants with surrounding tissue. Total monocytes/macrophages, tissue macrophages, T-cells and MHC-class-II-positive cells were morphometrically counted. On day 14, the macrophage/monocyte number was significantly higher for the controls than for the PPAAm samples. On day 56, the RM76AB and RM78AB samples had significantly lower numbers than RM77AB and the controls. The same was found for the tissue macrophages. No change over time and no differences between the implants were found for the T-cells. For the number of MHC-class-II-positive cells, a significant decrease was found only for the RM78AB implants between day 14 and day 56. Physico-chemical analysis of the PPAAm implants revealed that the RM77AB implants had the lowest water absorption, the highest nitrogen loss and the lowest oxygen uptake after sonication. These results demonstrate that the PPAAm samples and the controls were comparable regarding local inflammation, and that different plasma conditions lead to variations in the material properties which influence the tissue reaction.
Assuntos
Alilamina/toxicidade , Substitutos Ósseos , Inflamação/etiologia , Modelos Animais , Polímeros/toxicidade , Titânio/toxicidade , Animais , Antígenos de Histocompatibilidade Classe II/imunologia , Imuno-Histoquímica , Macrófagos/citologia , Masculino , Ratos , Ratos Endogâmicos Lew , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral/métodos , Linfócitos T/citologia , Raios XRESUMO
In the design of biomaterials for therapeutic application the evaluation of cellular/tissue responses play a key role. In this study, the in vivo bone-regenerative capacity and resorption of granular BONITmatrix and a paste-like bone substitution material on the basis of BONITmatrix were investigated in a rat cranial defect model. The results obtained with both biomaterials were compared to each other. For these, the paste-like composite and the granular BONITmatrix were implanted in adult male WOK-W rats, the skulls were harvested after eight weeks, and histopathological examinated. The comparison of the both tested biomaterials showed that the paste-like composite is much better to handle, the resorption of the material and the ossification process is much faster than those of granular BONITmatrix. The amount of newly formed bone was also measured and more bone formation was found in bone defects filled with the paste-like composite compared to those with granular BONITmatrix. The present study showed that both biomaterials could stimulate bone regeneration, but the paste-like composite leads in comparison to granular BONITmatrix to an accelerated more comprehensive bone regeneration.
Assuntos
Regeneração Óssea/efeitos dos fármacos , Substitutos Ósseos/administração & dosagem , Fosfatos de Cálcio/administração & dosagem , Dióxido de Silício/administração & dosagem , Crânio/efeitos dos fármacos , Crânio/patologia , Animais , Regeneração Óssea/fisiologia , Avaliação Pré-Clínica de Medicamentos/métodos , Masculino , Osteogênese/efeitos dos fármacos , Osteogênese/fisiologia , Ratos , Crânio/citologia , Resultado do TratamentoRESUMO
AIM: Surgery in cervical spine disease using titanium cages is a common procedure to reduce the pain and neurological deficits. This study was aimed to evaluate the results in pain reduction using the wing cage intraoperatively. METHOD: In this prospective study demographic data were noted, whereas special emphasis was placed on pain, which was noted using a visual pain scale and the prolo score, neurological deficits and the causing pathology. Furthermore, questions about the use of analgesics and the duration of pain were asked. After operation with insertion of a wing cage instead of the disk, a neurological investigation 6, 12 and 24 months later was done to evaluate the postoperative status. RESULTS: 54 patients underwent a cervical discectomy in 64 segments as therapy for neck pain or a radiculopathy caused by osteochondrosis or disc disorder. Patients with brachialgia profited most from the operation. Less improvement was seen in cases of osteochondrosis or combined pathology. CONCLUSION: Patients with pain caused by discs in the cervical spine, have better improvement than patients with other pathologies. This should be taken into account when choosing the mode of therapy.
Assuntos
Vértebras Cervicais/cirurgia , Deslocamento do Disco Intervertebral/epidemiologia , Deslocamento do Disco Intervertebral/cirurgia , Cervicalgia/epidemiologia , Cervicalgia/prevenção & controle , Fusão Vertebral/instrumentação , Fusão Vertebral/estatística & dados numéricos , Adulto , Idoso , Análise de Falha de Equipamento , Feminino , Alemanha/epidemiologia , Humanos , Deslocamento do Disco Intervertebral/diagnóstico , Prótese Articular , Laminectomia/instrumentação , Laminectomia/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Cervicalgia/diagnóstico , Medição da Dor , Prognóstico , Estudos Prospectivos , Medição de Risco/métodos , Fatores de Risco , Fusão Vertebral/métodos , Resultado do TratamentoRESUMO
Each of the trypanosome small nuclear ribonucleoproteins (snRNPs) U2, U4/U6, and U5, as well as the spliced leader (SL) RNP, contains a core of common proteins, which we have previously identified. This core is unusual because it is not recognized by anti-Sm Abs and it associates with an Sm-related sequence in the trypanosome small nuclear RNAs (snRNAs). Using peptide sequences derived from affinity-purified U2 snRNP proteins, we have cloned cDNAs for five common proteins of 8.5, 10, 12.5, 14, and 15 kDa of Trypanosoma brucei and identified them as Sm proteins SmF (8.5 kDa), -E (10 kDa), -D1 (12.5 kDa), -G (14 kDa), and -D2 (15 kDa), respectively. Furthermore, we found the trypanosome SmB (T. brucei) and SmD3 (Trypanosoma cruzi) homologues through database searches, thus completing a set of seven canonical Sm proteins. Sequence comparisons of the trypanosome proteins revealed several deviations in highly conserved positions from the Sm consensus motif. We have identified a network of specific heterodimeric and -trimeric Sm protein interactions in vitro. These results are summarized in a model of the trypanosome Sm core, which argues for a strong conservation of the Sm particle structure. The conservation extends also to the functional level, because at least one trypanosome Sm protein, SmG, was able to specifically complement a corresponding mutation in yeast.
Assuntos
Ribonucleoproteínas Nucleares Pequenas/genética , Spliceossomos/metabolismo , Trypanosoma brucei brucei/genética , Sequência de Aminoácidos , Animais , Clonagem Molecular , DNA Complementar , Dimerização , Teste de Complementação Genética , Dados de Sequência Molecular , Ribonucleoproteínas Nucleares Pequenas/metabolismo , Saccharomyces cerevisiae/genética , Homologia de Sequência de Aminoácidos , Trypanosoma brucei brucei/metabolismoRESUMO
In this retrospective analysis of 138 patients treated for ruptured aneurysms the development of shunt dependent hydrocephalus was evaluated regarding possible predictive factors. In 15 patients (11%) ventriculo-atrial shunt was implanted due to hydrocephalus. One predictive factor was the localisation of aneurysms as patients with hydrocephalus had PcoA aneurysms in 40% compared to 20% in the group of patients without hydrocephalus and only 7% compared to 28% MCA aneurysms. An other predictive factor was the severity of the subarachnoid haemorrhage (SAH) as 7 patients out of the 15 were graded Fisher IV on admission. Furthermore, an important predictive factor was the presence of acute hydrocephalus as 13 out of the 15 patients (87%) with shunt dependent hydrocephalus had acute hydrocephalus requiring external ventricular drainage. An other possible factor was the intraoperative opening of the lamina terminalis as in 73% of the patients with shunt dependent hydrocephalus compared to 82% in the group of patients without hydrocephalus this procedure was performed during surgery. The results suggest that shunt dependency is more likely after severe SAH especially in the presence of an acute hydrocephalus and in patients with aneurysms located in the basal cisterns. Therefore treatment of the acute hydrocephalus and possible the opening of the lamina terminalis could have a positive effect on the development of shunt dependent hydrocephalus after SAH.
Assuntos
Aneurisma Roto/cirurgia , Derivações do Líquido Cefalorraquidiano , Hidrocefalia/cirurgia , Aneurisma Intracraniano/cirurgia , Hemorragia Subaracnóidea/cirurgia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Aneurisma Roto/diagnóstico por imagem , Criança , Feminino , Seguimentos , Humanos , Hidrocefalia/diagnóstico por imagem , Aneurisma Intracraniano/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Exame Neurológico , Complicações Pós-Operatórias/diagnóstico por imagem , Estudos Retrospectivos , Hemorragia Subaracnóidea/diagnóstico por imagem , Tomografia Computadorizada por Raios XRESUMO
In trypanosomes all mRNAs are generated through trans mRNA splicing, requiring the functions of the small nuclear RNAs U2, U4 and U6. In the absence of conventional cis mRNA splicing, the structure and function of a U5-analogous snRNP in trypanosomes has remained an open question. In cis splicing, a U5 snRNP-specific protein component called PRP8 in yeast and p220 in man is a highly conserved, essential splicing factor involved in splice-site recognition and selection. We have cloned and sequenced a genomic region from Trypanosoma brucei, that contains a PRP8/p220-homologous gene (p277) coding for a 277 kDa protein. Using an antibody against a C-terminal region of the trypanosomal p277 protein, a small RNA of approximately 65 nucleotides could be specifically co-immunoprecipitated that appears to be identical with a U5 RNA (SLA2 RNA) recently identified by Dungan et al. (1996). Based on sedimentation, immunoprecipitation and Western blot analyses we conclude that this RNA is part of a stable ribonucleoprotein (RNP) complex and associated not only with the p277 protein, but also with the common proteins present in the other trans-spliceosomal snRNPs. Together these results demonstrate that a U5-analogous RNP exists in trypanosomes and suggest that basic functions of the U5 snRNP are conserved between cis and trans splicing.
Assuntos
Splicing de RNA , RNA Mensageiro/metabolismo , Ribonucleoproteína Nuclear Pequena U5/genética , Proteínas de Saccharomyces cerevisiae , Trypanosoma brucei brucei/genética , Animais , Centrifugação com Gradiente de Concentração , Clonagem Molecular , Eletroforese em Gel de Poliacrilamida , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Dados de Sequência Molecular , Testes de Precipitina , RNA Mensageiro/genética , RNA de Protozoário/genética , RNA de Protozoário/metabolismo , RNA Nuclear Pequeno/metabolismo , Ribonucleoproteína Nuclear Pequena U4-U6 , Ribonucleoproteína Nuclear Pequena U5/química , Ribonucleoproteína Nuclear Pequena U5/metabolismo , Saccharomyces cerevisiae/química , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Spliceossomos/genética , Trypanosoma brucei brucei/metabolismoAssuntos
Diabetes Mellitus Tipo 1/imunologia , Ilhotas Pancreáticas/patologia , Isoantígenos/imunologia , Animais , Células Cultivadas , Diabetes Mellitus Tipo 1/patologia , Haplótipos , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/imunologia , Complexo Principal de Histocompatibilidade , Ratos , Ratos Endogâmicos BB , Ratos Endogâmicos Lew , Ratos Endogâmicos , Fatores de Tempo , Transplante IsogênicoRESUMO
Aseptic pseudarthrosis may occur after all kinds of traumatology treatment. Following conservative treatment, incomplete immobilisation or an unattached bone fragment can be causal. After plate osteosynthesis the biomechanical principles are not efficient or the circulatory damage delays healing. There are two broad types of pseudarthrosis: vascular and nonvascular. The extent of vascularisation can be demonstrated by bone scintigraphy as well as X-ray. The treatment of vascular nonunions is very common. Mechanical stability is required, therefore a new osteosynthesis is desirable. Osteoporosis caused by inactivity and dislocation increases the rate of complications. Much more difficult problems are encountered in treatment of unreactive and avital pseudarthrosis, particularly in cases with a defect of bone substance. These defects can be treated with a segment transfer and a fibula-to-tibia operation. Extracorporal lithotripsy has been established as a new method in treatment of active and vascular nonunions. Former osteosynthesis is not a contraindication. Stability and immobilisation are necessary. Treatment in the low-frequency magnetic field shows no effect. Correct biomechanical and biological osteosynthesis with proper attention paid to location, quality of bone and asepsis can avoid the development of a pseudarthrosis.
Assuntos
Fixação de Fratura/métodos , Pseudoartrose/cirurgia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Placas Ósseas , Osso e Ossos/irrigação sanguínea , Diagnóstico por Imagem , Feminino , Humanos , Litotripsia/métodos , Masculino , Pessoa de Meia-Idade , Neovascularização Fisiológica , Pseudoartrose/diagnóstico , Pseudoartrose/reabilitação , Procedimentos Cirúrgicos Operatórios/métodosRESUMO
In trypanosomes mRNAs are generated through trans splicing. The spliced leader (SL) RNA, which donates the 5'-terminal mini-exon to each of the protein coding exons, plays a central role in the trans splicing process. We have established in vivo assays to study in detail trans splicing, cap4 modification, and RNP assembly of the SL RNA in the trypanosomatid species Leptomonas seymouri. First, we found that extensive sequences within the mini-exon are required for SL RNA function in vivo, although a conserved length of 39 nt is not essential. In contrast, the intron sequence appears to be surprisingly tolerant to mutation; only the stem-loop II structure is indispensable. The asymmetry of the sequence requirements in the stem I region suggests that this domain may exist in different functional conformations. Second, distinct mini-exon sequences outside the modification site are important for efficient cap4 formation. Third, all SL RNA mutations tested allowed core RNP assembly, suggesting flexible requirements for core protein binding. In sum, the results of our mutational analysis provide evidence for a discrete domain structure of the SL RNA and help to explain the strong phylogenetic conservation of the mini-exon sequence and of the overall SL RNA secondary structure; they also suggest that there may be certain differences between trans splicing in nematodes and trypanosomes. This approach provides a basis for studying RNA-RNA interactions in the trans spliceosome.
Assuntos
Capuzes de RNA/metabolismo , RNA Mensageiro/genética , RNA de Protozoário/genética , Trypanosomatina/genética , Animais , Sequência de Bases , Éxons/genética , Expressão Gênica , Dados de Sequência Molecular , Nematoides/genética , Conformação de Ácido Nucleico , Splicing de RNA , RNA Mensageiro/metabolismo , RNA de Protozoário/metabolismo , Especificidade da Espécie , Trypanosomatina/metabolismoAssuntos
Custos de Cuidados de Saúde/legislação & jurisprudência , Acessibilidade aos Serviços de Saúde/legislação & jurisprudência , Pessoas sem Cobertura de Seguro de Saúde/legislação & jurisprudência , Planos Governamentais de Saúde/legislação & jurisprudência , Controle de Custos/legislação & jurisprudência , Acessibilidade aos Serviços de Saúde/economia , Humanos , Minnesota , Planos Governamentais de Saúde/economia , Estados UnidosRESUMO
A number of 17.5- to 18.5-day-old fetal pancreases were grafted under the kidney capsule of streptozotocin-diabetic rats. Eight syngeneically grafted glands were sufficient to reverse the diabetes of the recipients within 4 weeks when the recipient rats were treated with insulin for 18 days after transplantation. Eight allogeneic fetal pancreases obtained from one donor strain were rejected after transplantation and the recipients relapsed into hyperglycemia immediately after insulin withdrawal. Eight allogeneic fetal pancreases obtained from eight MHC-different donor strains were also rejected and the recipients relapsed into hyperglycemia after insulin withdrawal. Using fetal pancreases as tissue sources, the combination of the allogeneic graft from different donor strains was not sufficient to prolong the survival time of the grafted tissue.
Assuntos
Transplante de Tecido Fetal , Rejeição de Enxerto , Transplante de Pâncreas , Animais , Feminino , Insulina/análise , Complexo Principal de Histocompatibilidade , Pâncreas/química , Pâncreas/embriologia , Gravidez , Ratos , Ratos Endogâmicos LewRESUMO
Two monoclonal Beta-cell surface antibodies M10H6 und K14D10 were obtained by fusion of spleen cells of Balb/c mice with the myeloma cell line P(3)0. The monoclonal antibody M10H6 was induced by immunization with rat insulinoma cells finally boostered with disintegrated rat islets, whereas the K14D10 was generated after immunization with porcine proinsulin. Both monoclonals belong to the IgG2A isotype and were screened with insulin-producing rat insulinoma cells by an indirect immunofluorescence test as well as by a cellular enzyme linked immunosorbent assay. In addition to the cell surface binding on living Beta cells the monoclonals react with islets on cryostat sections of rat pancreas. The anti-islet cytotoxic potential of these monoclonals was measured by 51Chromium-release in the presence of complement or Fc-receptor bearing leucocytes using 51Chromium-labelled rat islet cells as target. Both antibody secreting hybridomas were propagated in syngeneic mice resulting in high levels of islet cell surface antibodies in ascites and sera from the recipient. High anti-islet cytotoxicity was mediated by ascites fluid, but no mouse developed hyperglycaemia. Furthermore, the repeated injections of the monoclonals into rats did not exert a diabetogenic action and failed to reduce the pancreatic insulin content although the attraction of the K14D10 to the pancreatic islets in vivo could be demonstrated. We conclude that islet cell surface antibody-mediated Beta-cell lysis in vitro may not be relevant to Beta-cell destruction in vivo.