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1.
BMC Pediatr ; 22(1): 158, 2022 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-35346133

RESUMO

BACKGROUND: Early support for children with developmental disabilities is crucial but frequently unavailable in low-resource settings. We conducted a mixed-methods evaluation to assess the feasibility, acceptability, and impact of a programme of early detection and intervention for young children with developmental disabilities in Western Uganda. METHODS: Early child development training for healthcare workers (HCWs) was implemented in three rural districts, and attendance was tracked. HCW knowledge and confidence were assessed pre-/post-intervention, and referral numbers tracked to evaluate impact. Facilitators were trained and mentored to deliver a participatory, group, early intervention programme (EIP) for young children with developmental disabilities and their families. Facilitators were tracked as they were identified, trained, and delivered the intervention, and attendance of families was tracked. Pre-/post-intervention assessments evaluated changes in family quality of life (PedsQL 2.0, Family Impact Module), and child nutritional outcomes. Focus group discussions with stakeholders also assessed feasibility, acceptability and impact. RESULTS: Overall, 93 HCWs from 45 healthcare facilities received training. In the pre-/post-evaluation, median knowledge and confidence scores increased significantly (from 4.0 to 7.0 and from 2.7 to 4.7, respectively (p < 0.001)). HCWs reported feeling empowered to refer and offer care for families with a young child with disability. Referral rates increased significantly from 148 to 251 per annum (70%; p = 0.03). Eleven EIP facilitators were trained, and all delivered the intervention; 84 families were enrolled, of which 78% attended at least 6 out of 10 modules. Amongst those with paired pre-/post-intervention data (n = 48), total family quality of life scores increased significantly (21%, p < 0.001). Improvements were seen across all domains of quality of life, with the largest impacts on emotional functioning and social functioning (p < 0.001). The programme was acceptable to caregivers and facilitators. Caregivers reported improved knowledge, family relationships, hope, emotional wellbeing, and reduced self-stigma. CONCLUSIONS: A programme of early detection and intervention for children with early developmental disabilities and their families was feasible and acceptable in a rural community-based Ugandan setting. HCW training positively impacted knowledge, confidence, attitudes, and referral rates. Families enrolled to the EIP reported significant improvements in quality of life. Important programmatic barriers identified included geographical spread, poverty, gender inequality, and stigma.


Assuntos
Deficiências do Desenvolvimento , Qualidade de Vida , Cuidadores/educação , Criança , Pré-Escolar , Deficiências do Desenvolvimento/diagnóstico , Deficiências do Desenvolvimento/terapia , Família , Humanos , Qualidade de Vida/psicologia , Uganda
2.
Nat Genet ; 14(3): 334-6, 1996 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-8896566

RESUMO

Many organophosphorus compounds (OPs) are potent cholinesterase inhibitors, accounting for their use as insecticides and, unfortunately, also as nerve agents. Each year there are approximately 3 million pesticide poisonings world-wide resulting in 220,00 deaths. In 1990, there were 1.36 million kg of chlorpyrifos, 4.67 million kg of diazinon and 1.23 million kg of ethyl parathion manufactured in the USA (data supplied by the USEPA). In addition to exposure risks during pesticide manufacturing, distribution and use, there are risks associated with the major international effort aimed at destroying the arsenals of nerve agents, including soman and sarin. The United States has pledged to destroy approximately 25,000 tons of chemical agents by the end of the decade. The high density lipoprotein (HDL)-associated enzyme paraoxonase (PON1) contributes significantly to the detoxication of several OPs (Fig. 1). The insecticides parathion, chlorpyrifos and diazinon are bioactivated to potent cholinesterase inhibitors by cytochrome P-450 systems. The resulting toxic oxon forms can be hydrolysed by PON1, which also hydrolyses the nerve agents soman and sarin (Fig. 1). PON1 is polymorphic in human populations and different individuals also express widely different levels of this enzyme. The Arg192 (R192) PON1 isoform hydrolyses paraoxon rapidly, while the Gln192 (Q191) isoform hydrolyses paraoxon slowly. Both isoforms hydrolyse chlorpyrifos-oxon and phenylacetate at approximately the same rate. The role of PON1 in OP detoxication is physiologically significant. Injected PON1 protects against OP poisoning in rodent model systems and interspecies differences in PON1 activity correlate well with observed median lethal dose (LD50) values. We report here a simple enzyme analysis that provides a clear resolution of PON1 genotypes and phenotypes allowing for a reasonable assessment of an individual's probable susceptibility or resistance to a given OP, extending earlier studies on this system. We also show that the effect of the PON1 polymorphism is reversed for the hydrolysis of diazoxon, soman and especially sarin, thus changing the view of which PON1 isoform is considered to be protective.


Assuntos
Esterases/sangue , Esterases/genética , Compostos Organofosforados/metabolismo , Sarina/metabolismo , Soman/metabolismo , Arildialquilfosfatase , Substâncias para a Guerra Química/metabolismo , Substâncias para a Guerra Química/farmacologia , Resistência a Medicamentos/genética , Esterases/efeitos dos fármacos , Homozigoto , Humanos , Isoenzimas , Compostos Organofosforados/farmacologia , Polimorfismo Genético , Sarina/farmacologia , Soman/farmacologia , América do Sul
3.
Indian J Crit Care Med ; 17(2): 116-8, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23983420

RESUMO

Neuroleptic malignant syndrome (NMS) is a rare but well described complication of the administration of antipsychotic agents. Compartment syndrome, with increased pressures within the confined space of fascial sheaths leading to compression damage of the contained tissue, similarly is well described. Brachial plexus injuries caused by patient malposition are also very rare but a few cases have been reported. We report a case where these three complications occurred together. This was attributable to the patient developing NMS whilst asleep in the prone position overnight.

4.
Injury ; 50(8): 1483-1488, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31213306

RESUMO

AIMS: Fractures and dislocations of the midfoot are relatively uncommon but can be life changing injuries. Within the literature, there has been scant specific reference to the identification and management of medial ray injuries in midfoot trauma. Moreover, it is appreciated that these injuries are associated with poor outcomes. We aim to clearly define these injury characteristics and demonstrate fixation techniques. PATIENTS AND METHODS: A retrospective review of the case notes and imaging was conducted for operatively treated midfoot injuries between January 2013 and January 2018. RESULTS: 161 patients were identified, 31 of these with imaging and operative diagnosis suggestive of medial ray injury. Studying these 31 injuries revealed five patterns of injury. CONCLUSION: When treating midfoot trauma, it is important to fully understand the injury pattern as this dictates the principles and techniques of fixation. Identification and knowledge of these five injury patterns will aid surgeons in future management of these injuries and may improve treatment outcomes.


Assuntos
Traumatismos do Pé/classificação , Fixação Interna de Fraturas/métodos , Fraturas Ósseas/classificação , Luxações Articulares/classificação , Adolescente , Adulto , Idoso , Fenômenos Biomecânicos , Feminino , Traumatismos do Pé/diagnóstico por imagem , Traumatismos do Pé/fisiopatologia , Traumatismos do Pé/cirurgia , Fraturas Ósseas/diagnóstico por imagem , Fraturas Ósseas/fisiopatologia , Fraturas Ósseas/cirurgia , Humanos , Luxações Articulares/diagnóstico por imagem , Luxações Articulares/fisiopatologia , Luxações Articulares/cirurgia , Masculino , Pessoa de Meia-Idade , Procedimentos Ortopédicos , Radiografia , Estudos Retrospectivos , Resultado do Tratamento , Adulto Jovem
5.
Bone Joint J ; 100-B(2): 176-182, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29437059

RESUMO

AIMS: Fractures of the navicular can occur in isolation but, owing to the intimate anatomical and biomechanical relationships, are often associated with other injuries to the neighbouring bones and joints in the foot. As a result, they can lead to long-term morbidity and poor function. Our aim in this study was to identify patterns of injury in a new classification system of traumatic fractures of the navicular, with consideration being given to the commonly associated injuries to the midfoot. PATIENTS AND METHODS: We undertook a retrospective review of 285 consecutive patients presenting over an eight- year period with a fracture of the navicular. Five common patterns of injury were identified and classified according to the radiological features. Type 1 fractures are dorsal avulsion injuries related to the capsule of the talonavicular joint. Type 2 fractures are isolated avulsion injuries to the tuberosity of the navicular. Type 3 fractures are a variant of tarsometatarsal fracture/dislocations creating instability of the medial ray. Type 4 fractures involve the body of the navicular with no associated injury to the lateral column and type 5 fractures occur in conjunction with disruption of the midtarsal joint with crushing of the medial or lateral, or both, columns of the foot. RESULTS: In order to test the reliability and reproducibility of this new classification, a cohort of 30 patients with a fracture of the navicular were classified by six independent assessors at two separate times, six months apart. Interobserver reliability and intraobserver reproducibility both had substantial agreement, with kappa values of 0.80 and 0.72, respectively. CONCLUSION: We propose a logical, all-inclusive, and mutually exclusive classification system for fractures of the navicular that gives associated injuries involving the lateral column due consideration. We have shown that this system is reliable and reproducible and have described the rationale for the subsequent treatment of each type. Cite this article: Bone Joint J 2018;100-B:176-82.


Assuntos
Traumatismos do Pé/classificação , Fraturas Ósseas/classificação , Ossos do Tarso/lesões , Traumatismos do Pé/diagnóstico por imagem , Fraturas Ósseas/diagnóstico por imagem , Humanos , Reprodutibilidade dos Testes , Estudos Retrospectivos , Ossos do Tarso/diagnóstico por imagem , Tomografia Computadorizada por Raios X
6.
Mol Cell Biol ; 21(20): 7010-9, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11564883

RESUMO

Y-box proteins are major constituents of ribonucleoprotein particles (RNPs) which contain translationally silent mRNAs in gametic cells. We have recently shown that a sequence-specific RNA binding activity present in spermatogenic cells contains the two Y-box proteins MSY2 and MSY4. We show here that MSY2 and MSY4 bind a sequence, 5'-UCCAUCA-3', present in the 3' untranslated region of the translationally repressed protamine 1 (Prm1) mRNA. Using pre- and post-RNase T1-digested substrate RNAs, it was determined that MSY2 and MSY4 can bind an RNA of eight nucleotides containing the MSY2 and MSY4 binding site. Single nucleotide mutations in the sequence eliminated the binding of MSY2 and MSY4 in an electrophoretic mobility shift assay, and the resulting mutants failed to compete for binding in a competition assay. A consensus site of U(AC)C(A)CAU(C)CA(CU) (subscripts indicate nucleotides which do not disrupt YRS binding by MSY2 and MSY4), denoted the Y-box recognition site (YRS), was defined from this mutational analysis. These mutations in the YRS were further characterized in vivo using a novel application of the yeast three-hybrid system. Experiments with transgenic mice show that disruption of the YRS in vivo relieves Prm1-like repression of a reporter gene. The conservation of the RNA binding motifs among Y-box protein family members raises the possibility that other Y-box proteins may have previously unrecognized sequence-specific RNA binding activities.


Assuntos
Regiões 3' não Traduzidas , Proteínas de Ligação a DNA/metabolismo , Protaminas/metabolismo , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/metabolismo , Animais , Sequência de Bases , Sítios de Ligação , Ligação Competitiva , Sequência Conservada , DNA/metabolismo , Relação Dose-Resposta a Droga , Genes Reporter , Immunoblotting , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Modelos Genéticos , Dados de Sequência Molecular , Mutação , Regiões Promotoras Genéticas , Ligação Proteica , Biossíntese de Proteínas , RNA/metabolismo , Homologia de Sequência do Ácido Nucleico , Fatores de Transcrição , Técnicas do Sistema de Duplo-Híbrido , Raios Ultravioleta
7.
J Med Chem ; 37(5): 674-88, 1994 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-8126708

RESUMO

Systematic modification of the presumed P1 side chain in a series of (carboxyalkyl)amino-based inhibitors of matrix metalloproteinases enabled identification of the 2-(1,3-dihydro-1,3-dioxo-2H-benz[f]isoindol-2-yl)ethyl group as a preferred substituent imparting potent inhibition of the enzymes collagenase and gelatinase. It was subsequently found that the P2'-P3' residues in this series could be replaced by small non-peptide residues, while maintaining inhibitory potency. The imide group in this series of compounds can undergo autocatalytic hydrolysis under neutral conditions.


Assuntos
Dipeptídeos/química , Matriz Extracelular/enzimologia , Indóis/química , Metaloendopeptidases/antagonistas & inibidores , Zinco , Sequência de Aminoácidos , Compostos Cromogênicos/metabolismo , Dipeptídeos/síntese química , Dipeptídeos/farmacologia , Estabilidade de Medicamentos , Corantes Fluorescentes , Gelatinases/antagonistas & inibidores , Meia-Vida , Humanos , Concentração de Íons de Hidrogênio , Indóis/síntese química , Indóis/farmacologia , Isoindóis , Metaloproteinase 3 da Matriz , Inibidores de Metaloproteinases de Matriz , Dados de Sequência Molecular , Estrutura Molecular , Relação Estrutura-Atividade
8.
J Histochem Cytochem ; 42(8): 1055-60, 1994 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-7913105

RESUMO

Thyroid C-cells have the capacity to produce a variety of peptides, as do C-cell tumors. The cellular content of one such peptide, somatostatin, is restricted to a minority of C-cells in rat and human. We set out to clarify whether the synthesis of somatostatin is equally restricted and to study changes that occur in somatostatin synthesis with age. We used immunocytochemistry to localize somatostatin and calcitonin in conjunction with in situ hybridization, using digoxigenin-labeled oligoprobes to localize somatostatin and calcitonin mRNAs in serial sections of formalin-fixed, paraffin-embedded rat thyroid, and correlated peptide and mRNA content in individual cells. All C-cells synthesize and store calcitonin, and somatostatin synthesis, as shown by mRNA content, is limited to the subset of cells containing immunoreactive somatostatin. The numbers of C-cells in general and of the subset synthesizing somatostatin increase between juvenile and adult animals, but the somatostatin cells remain confined to a small area of the gland. These findings support the proposal that somatostatin production is not facultative, but that C-cells differentiate into two distinct subsets of cells, only one of which synthesizes and stores somatostatin.


Assuntos
Envelhecimento/metabolismo , Calcitonina/metabolismo , RNA Mensageiro/metabolismo , Somatostatina/metabolismo , Glândula Tireoide/metabolismo , Animais , Calcitonina/genética , Digoxigenina , Feminino , Técnicas Imunoenzimáticas , Hibridização In Situ , Masculino , Ratos , Ratos Wistar , Somatostatina/genética , Glândula Tireoide/citologia
9.
J Clin Pathol ; 46(2): 171-4, 1993 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8459039

RESUMO

The value of formamide for use in in situ hybridisation (ISH) for the detection of mRNA, using either single or multi probe cocktails of digoxigenin labelled oligoprobes, was investigated. Three peptides with cell specific localisation in three separate tissues--calcitonin in the thyroid, epidermal growth factor (EGF) in the submaxillary gland, and insulin in the pancreas were studied. In each case localisation was confined to the appropriate cell type, but in the presence of formamide higher concentrations of probe and a longer development time were required. The abolition of formamide from the protocol for ISH makes the technique safer, cheaper, faster and more suitable for routine diagnostic use.


Assuntos
Digoxigenina , Hibridização In Situ/métodos , Sondas de Oligonucleotídeos , RNA Mensageiro/análise , Animais , Calcitonina/análise , Fator de Crescimento Epidérmico/análise , Formamidas , Insulina/análise , Masculino , Ratos , Ratos Wistar
10.
J Hosp Infect ; 10(1): 4-9, 1987 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-2888809

RESUMO

The heat shock technique (heating a culture at 55 degrees C for 3 min immediately before phage typing) has been used in our laboratory as an adjunct to routine phage typing for 2 years. This has enabled phage typing patterns to be determined on isolates otherwise recorded as untypable. The method is easily performed and standardized. Phage patterns were found to be reproducible and adequate discrimination was achieved. We found the technique provided significant information which was not available by conventional typing.


Assuntos
Tipagem de Bacteriófagos/métodos , Temperatura Alta , Fagos de Staphylococcus , Staphylococcus/classificação , Técnicas Bacteriológicas
11.
N Z Med J ; 102(872): 367-9, 1989 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-2529458

RESUMO

During the three years 1985 to 1987 an increasing number of methicillin-resistant Staphylococcus aureus (MRSA) strains were identified in New Zealand each year. A total of 66 strains of MRSA were identified among isolates received from 418 patients and health personnel. The majority (337/418, 80.6%) of the isolates were from two independent large outbreaks of MRSA. All strains of MRSA were sensitive to vancomycin, rifampicin and fusidic acid. An overseas origin, usually Australia, was identified for 48.4% of strains. The majority of isolates were from patients whose host defences had been breached. Postoperative and cutaneous wounds were the commonest sites of acquisition.


Assuntos
Infecção Hospitalar/epidemiologia , Surtos de Doenças , Meticilina/farmacologia , Resistência às Penicilinas , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus/efeitos dos fármacos , Antibacterianos/farmacologia , Tipagem de Bacteriófagos/métodos , Infecção Hospitalar/microbiologia , Humanos , Nova Zelândia/epidemiologia , Resistência às Penicilinas/fisiologia , Infecções Estafilocócicas/transmissão , Fagos de Staphylococcus/classificação , Staphylococcus aureus/classificação , Staphylococcus aureus/isolamento & purificação , Fatores de Tempo
12.
Ups J Med Sci ; 86(1): 1-8, 1981.
Artigo em Inglês | MEDLINE | ID: mdl-7303328

RESUMO

When red cells are incubated in the dark in the presence of the dye Rose Bengal and subsequently irradiated with visible light, they hemolyze. Under certain conditions some of the hemoglobin is expelled in the form of a convective jet and appears as a transient cloud beside the cell. Elastic contraction of the membrane is not a sufficient driving force for the jet. A plausible mechanism (an osmotic "pump") is presented.


Assuntos
Eritrócitos/fisiologia , Hemólise , Hemólise/efeitos da radiação , Corantes/farmacologia , Membrana Eritrocítica/fisiologia , Hemoglobinas/metabolismo , Hemólise/efeitos dos fármacos , Humanos , Luz , Concentração Osmolar
14.
J Cell Sci ; 20(2): 289-307, 1976 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-57119

RESUMO

From quantitative electron-microscope observations on the binding of permanganate to regions of erythrocytes and reticulocytes of known chemical composition, it is concluded that KMnO4, like phosphotungstic acid (PTA), binds preferentially to sites on proteins. Compared with PTA, KMnO4 binding exhibits less anomalous behaviour. The data support the hypothesis previously put forward that the 2 regions, or phases, in condensed chromatin differ in both molecular composition and concentration. The increase in binding to protein which occurs during nuclear haemolysis is interpreted in terms of protein-protein interaction in the chromatin of the intact cell.


Assuntos
Núcleo Celular/ultraestrutura , Cromossomos/ultraestrutura , Permanganato de Potássio/metabolismo , Animais , Sítios de Ligação , Embrião de Galinha , Galinhas , Cromatina/metabolismo , DNA/metabolismo , Eritrócitos/metabolismo , Eritrócitos/ultraestrutura , Histonas/metabolismo , Ácido Fosfotúngstico/metabolismo , Reticulócitos/metabolismo , Coloração e Rotulagem
15.
Stain Technol ; 58(1): 29-40, 1983 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-6192551

RESUMO

The staining of thin sections with lead citrate shows an initial increase followed by a decrease much later; the rate of the initial increase and subsequent loss varies for different cellular components. The decrease eventually reaches a stable minimum. At this level electron scattering is less than that of unstained sections, demonstrating a loss of biological material. Lead citrate used as a poststain following uranyl acetate causes an increase in electron density that is independent of staining time over 1-30 min; this increase appears to depend only on the quantity of uranyl acetate already bound, implying that the lead binds predominantly to the uranyl acetate.


Assuntos
Citratos , Coloração e Rotulagem , Animais , Galinhas , Ácido Cítrico , Eritrócitos/ultraestrutura , Glutaral , Cinética , Fígado/ultraestrutura , Masculino , Camundongos , Microscopia Eletrônica , Ouriços-do-Mar , Testículo/ultraestrutura
16.
J Cell Sci ; 17(1): 113-39, 1975 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-47863

RESUMO

Adult hen erythrocyte nuclei are isolated from cells or haemolysed in situ by acting on the plasma membrane with rotating knives or with non-ionic detergents. When the isolation medium contains magnesium ions (1 mM), sucrose (0-4 M) and Tris buffer (0.01 M, pH 7-5) called SMTOG (see text), the ultrastructure in thin sections through the condensed chromatin bodies, after staining with either uranyl-lead or phosphotungstic acid (PTA), is similar to that found in the intact cell. Hence it can be concluded that the 2 phases which comprise chromatin, the o- and e-phase, survive nuclear isolation. These are so called because the structural units in chromatin are arranged at the surface of the nucleus into one or more layers and give rise to oddly (o) and evenly (e) numbered bands. The 0-phase is also largely retained after extensive washing in 0-07 M NaC1 as shown by electron microscopy and biochemical measurements; only 6% of the total nuclear protein is removed, a value small compared with the fractional amount of the chromatin protein calculated to lie in the o-phase, about 70%. After extensive washing in saline-EDTA there are structural changes in chromatin, but biochemical data show that the molecules in the o-phase are also largely retained; loss of protein amounts to between 5 and 11%. These data suggest that the o-phase is a structural component of the chromatin bodies. They support the hypothesis that condensed chromatin is formed by folding superunit threads. These units consist of a central thread-like element about 17 nm diameter which stains preferentially with uranyl-lead and forms the e-phase, with an outer cylindrical shell forming the o-phase of total diameter about 28nm. The 5-10% proteins removed by salt washes are located exclusively in a particulate component, quite likely the chromatin. They have been examined by sodium dodecyl sulphate (SDS) polyacrylamide gel electrophoresis. There are about 10 or more protein species, ranging in molecular weight from 21000 upwards. The groups of large granules previously found in the nuclear sap of intact erythrocytes are shown to be associated with an amorphous or finely fibrillar body.


Assuntos
Cromatina , Eritrócitos/ultraestrutura , Animais , Proteínas Sanguíneas/análise , Divisão Celular , Núcleo Celular/análise , Núcleo Celular/ultraestrutura , Galinhas , Cromatina/análise , Cromatina/ultraestrutura , Citoplasma/análise , DNA/análise , Eletroforese em Gel de Poliacrilamida , Eritrócitos/análise , Hemoglobinas/análise , Hemólise , Histonas/análise , Magnésio , Microscopia Eletrônica , Modelos Estruturais , Ácido Fosfotúngstico , Polietilenoglicóis , Espectrofotometria , Coloração e Rotulagem , Sacarose , Trometamina
17.
J Cell Sci ; 17(3): 263-85, 1975 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-1127023

RESUMO

Previously it was shown that the nuclear envelope-limited sheets of chromatin, monolayers of nucleoprotein structural units, are present in blood cells from 4 classes of vertebrates. Now we show that sheets of similar width are present in certain leukocytes of a fifth class, a teleost fish. We describe the fine structure of leukocytes in peripheral blood and in the main haematopoietic organ, kidney. We also examined the granulocytes of connective tissue in intestine. By May-Grunwald-Giemsa staining and electron microscopy heterophilic granulocytes, cosinophils but no basophils could be recognized in peripheral blood and kidney. Problems in classification of the cells are discussed. In one group (A) of 5 fish, sheets occurred at a frequency of roughly 1% in heterophilic (type 1) granulocytes and lymphocytes from peripheral blood. No sheets were found in a second group (B) of 5 fish. Kidney and intestine were examined in some fish from both groups and no sheets were present. In an atypical group (C) sheets were found in the eosinophilic (type 2) granulocytes from peripheral blood of one fish and in lymphocytes from connective tissue of intestine in another. Sheets were usually associated with nuclei of irregular shape and their width averaged 36 nm. We tabulate data from other workers on occurence and width of sheets. They are found in all the main classes of tissue in mammals, namely blood and other connective tissues, in epithelial, nervous, germinal tissue and muscle, as well as in invertebrate and certain plants. Their nearly constant width, average value 35 nm, provides very convincing evidence for the hypothesis that the molecules of DNA and protein are organized into the same fundamental structural units, irrespective of species. We discuss the variable incidence of sheets among different cell types and the factors which might determine this.


Assuntos
Cromatina/ultraestrutura , Peixes/sangue , Leucócitos/ultraestrutura , Animais , Núcleo Celular/ultraestrutura , Granulócitos/ultraestrutura , Intestinos/ultraestrutura , Rim/ultraestrutura , Linfócitos/ultraestrutura , Microscopia Eletrônica , Especificidade de Órgãos , Especificidade da Espécie
18.
J Cell Sci ; 35: 59-66, 1979 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-422683

RESUMO

The arrangement of the chromatin bodies in the interphase nuclei of 6 erythrocytes has been investigated by means of 3-dimensional reconstruction from electron micrographs of serial sections. When the borders of chromatin bodies are marked on the surface of each model, discrete areas of chromatin in contact with the nuclear envelope are revealed. The number of these areas in approximately equal to the number of chromosomes in the diploid set. The data suggest that each chromatin body corresponds to a condensed interphase chromosome and that each chromosome is attached to one discrete site on the nuclear envelope. The data are insufficient to show whether or not the condensed chromosomes are arranged in any orderly pattern in these nuclei.


Assuntos
Cromatina/ultraestrutura , Eritrócitos/ultraestrutura , Triturus/sangue , Animais , Núcleo Celular/ultraestrutura , Cromossomos/ultraestrutura , Microscopia Eletrônica , Modelos Estruturais , Membrana Nuclear/ultraestrutura
19.
J Cell Sci ; 55: 157-87, 1982 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-6286694

RESUMO

Large granule complexes are structures found in a small percentage of chicken erythrocyte nuclei when observed in ultra-thin sections in the electron microscope. They consist of an amorphous region associated with a number of large (approximately 30 min) granules. We have shown, by a novel use of phenylhydrazine to synchronize populations of chicken erythrocytes in vivo, that large granule complexes do not occur in the nuclei until the cells have reached one-third to one-half of their normal intravascular lifespan. The mature large granule complexes are formed by aggregation of pre-existing fibrillar, granular and amorphous material, and their presence is correlated with the presence of another ultrastructural feature of the nucleus, the so-called "filled cavities' in the chromatin. Digestion of ultra-thin sections of erythrocytes embedded in the hydrophilic resin glycol methacrylate (GMA) has shown that the major component of the amorphous region is a rather acidic protein that is not haemoglobin, the most abundant protein in the erythrocyte. The large granules also contain protein and, almost certainly, RNA. The problems encountered in reaching this conclusion have emphasized the lack of unambiguous cytochemical tests for use on ultra-thin sections. We have shown that the large granule complex differs in many respects from the nucleolus in the erythrocyte series, even though the two organelles have certain superficial similarities such as their overall dimensions and the presence of granular and fibrillar regions. The most likely function of the large granule complex is as a repository for material, including RNA, the processing of which has ceased in the inactivated erythrocyte nucleus.


Assuntos
Eritrócitos/ultraestrutura , Animais , Proteínas Sanguíneas/metabolismo , Núcleo Celular/metabolismo , Núcleo Celular/ultraestrutura , Galinhas , Quimotripsina , Desoxirribonucleases , Endonucleases , Envelhecimento Eritrocítico , Eritrócitos/metabolismo , Microscopia Eletrônica , Pepsina A , Pronase , Reticulócitos/metabolismo , Reticulócitos/ultraestrutura , Ribonuclease Pancreático , Ribonucleases , Tripsina
20.
J Cell Sci ; 54: 207-40, 1982 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-6176587

RESUMO

The EDTA regressive staining procedure to detect RNA (Bernhard's technique) is based on the proposition that after staining ultrathin sections with uranyl the stain is preferentially removed from DNA rather than RNA by the action of the chelating agent EDTA. Whilst attempting to use the EDTA regressive staining procedure to detect the presence of RNA in the large granule complexes of chicken erythrocyte nuclei, certain anomalous staining patterns were observed in the chromatin of these nuclei. Essentially, these were that the edges of condensed chromatin bodies stained positively for RNA even though this molecule is known not to be present there in significant quantities. The staining patterns suggested that chromatin was retaining its stain in a manner expected of RNA but not DNA as a consequence of EDTA-containing species failing to pass freely through the section. This hypothesis was tested by carrying out the EDTA procedure on embedded specimens of a DNA-containing virus, simian virus 40 (SV40), small enough not to be exposed at the surface of the section. In this way it has been shown that virus particles completely surrounded by resin destain so much more slowly than chromatin, which is accessible at the surface of the section, that without any other information it would be concluded that the viruses contained RNA, not DNA. This apparently anomalous result arises because the difficulties encountered by stain or EDTA molecules in passing through a plastic section were not appreciated at the time of the initial publication of the technique. The observations are discussed in the light of recent knowledge that has been gained on the kinetics of staining by measuring the electron-scattering densities of stained sections, similar measurements having been made on sections stained by Bernhard's technique. A model for the mechanism of the EDTA regressive staining technique consistent with the experimental observations is proposed and the conditions under which Bernhard's staining procedure retains its specificity are defined. Briefly, these conditions are that: (a) the sections be stained for only a short period with uranyl before treating them with EDTA even though such brief staining is undesirable for quantitative measurements of stain uptake into biological material; and (b) that sections stained in lead only be compared as controls with sections stained by Bernhard's technique so that any specificity of lead for sub-cellular components is not confused with a positive indication of the presence of RNA. Unless these conditions are fulfilled, results obtained by the use of the regressive staining technique may be highly misleading.


Assuntos
Eritrócitos/ultraestrutura , Fígado/ultraestrutura , RNA/análise , Animais , Galinhas , Ácido Edético , Feminino , Microscopia Eletrônica , RNA Viral/análise , Reticulócitos/ultraestrutura , Vírus 40 dos Símios/ultraestrutura , Coloração e Rotulagem
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