RESUMO
A method is described for the measurement of inulin and PAH clearances in rats without killing the animal. Inulin clearance measurements of partially nephrectomized rats and sham-control rats were made before operation and at intervals following the operation; inulin clearances were determined on normal rats at intervals during their growth. In another series of partially nephrectomized rats and their sham-operated controls, inulin and PAH clearances were determined in all the animals before and at intervals following the operation. Glomerular counts were made in some rats. After partial nephrectomy the inulin clearance is reduced but not as much as would be expected considering the amount of renal tissue removed. The mean inulin clearance per nephron is greatly increased in the partially nephrectomized rat when compared to the value determined for the control rat. The inulin clearance of the partially nephrectomized rat shows a progressive decline which is first clearly evident about 6 months after operation. The sham-operated rats showed an inulin clearance slightly less than that of nonoperated controls about 24 to 30 wk after the operation. In the normal rats the inulin clearance relative to body weight is much greater in rats with a mean weight of 197 +/- 3 g than in normals which are older and heavier. The PAH dearance of the partially nephrectomized rat is reduced following operation but undergoes no further change in the ensuing 24 wk.
Assuntos
Ácidos Aminoipúricos , Inulina , Nefropatias , Testes de Função Renal , Nefrectomia , Animais , RatosRESUMO
Kidney from normal male albino rats, of body weight 170-200 g, was fixed by arterial perfusion with buffered tannic acid-glutaraldehyde, and postfixed with osmium tetroxide. Random and isotropic ultrathin sections from 23 different glomeruli from five rats were mounted on slot grids for staining and electron microscopy. Prints of whole glomeruli at a magnification of 3,909 were analyzed by stereological methods. The mean glomerular volume was (8.048 +/- 0.474) X 10(5) mum3 if the glomeruli are treated as spheres. The area of the basement membrane was 0.281 +/- 0.017 mm2 per glomerulus, of which 0.184 +/- 0.011 mm2 represents peripheral basement membrane. The aggregate epithelial slit length per glomerulus was 65.19 +/- 3.84 cm, of which 48.69 +/- 2.87 cm represents epithelial slits abutting on the peripheral basement membrane. Assuming that a slit diaphragm is 390 A wide, and that the pores of the slit diaphragm represent 26% of its area, the mean pore area is 3.96 cm2, of which 2.96 cm2 represents the area of peripheral pores. These findings are discussed in the context of the hydrodynamic theory of glomerular ultrafiltration. We conclude that the porous substructure of the glomerular slit diaphragm is significant in determining the hydraulic conductivity of the glomerulus and hence also solute flux during ultrafiltration.
Assuntos
Glomérulos Renais/ultraestrutura , Animais , Membrana Basal/ultraestrutura , Epitélio/ultraestrutura , Taxa de Filtração Glomerular , Glomérulos Renais/fisiologia , Masculino , RatosRESUMO
Wide fields of tissue can be rapidly examined by electron microscopy by use of Formvar films for the support of ultrathin sections on slot grids. The intervention of the grid bars of conventional mesh grids is avoided, and a continuous micrograph of the specimen at scanning magnifications can be obtained. Enough material is sublimed from the section and the supporting film by deliberate exposure to the electron beam to permit one to obtain an image with good contrast. This method of examination, which takes in all about two hours, permits examination of an extensive area of tissue in relation both to its topography at low magnifications and to its ultrastructural detail, and accordingly adds to electron microscopy a dimension characteristic of the lower powers of the light microscope. It offers the histopathologist the option of using micrographs taken during the scanning survey of a tissue to detect regions that can be readily re-examined at high magnification in the same ultrathin section.
Assuntos
Microscopia Eletrônica/métodos , Animais , Pré-Escolar , Feminino , Humanos , Rim/ultraestrutura , Glomérulos Renais/ultraestrutura , Microscopia Eletrônica/instrumentação , Ratos , Pele/ultraestruturaRESUMO
Total-field electron-microscopic examination of tissue slices of 50--200 micrometers thickness, used in various prestaining methods, can be accomplished by combining the following two technics: surface-embedding, a process in which the thin tissue slice remains on one plane during embedding, so that its entire cross section can be obtained; multiple-mesa technic, a trimming process to obtain multiple targets for examination on the same field. The two technics are described in detail.
Assuntos
Microscopia Eletrônica , Microtomia/métodos , HumanosRESUMO
Specimens destined for light and electron microscopy were fixed in a modified buffered formalin, postosmicated, dehydrated, and embedded in a mixture of epoxy resins (Epon-araldite) in large plastic molds. These blocks were sectioned at 0.5 to 1 micron on a JB-4 microtome and stained with a combined nuclear and cytoplasmic stain (Paragon). The sections were examined by light microscopy for diagnostic evaluation. If ultrastructural examination was also desired, the selected area was isolated using the "mesa" technique. The trimmed block was then sectioned on an ultramicrotome, picked up on grids, stained, and examined in the electron microscope. We think these techniques offer the diagnostic pathologist the potential of viewing 1-micron sections at a light microscopy level with the option of subsequent electron microscopy of the same area of the same block.
Assuntos
Técnicas Histológicas , Doença de Hodgkin/patologia , Humanos , Microscopia , Microscopia Eletrônica , Microtomia , Manejo de EspécimesAssuntos
Adenoma de Células das Ilhotas Pancreáticas/diagnóstico , Desidratação/diagnóstico , Diarreia/diagnóstico , Neoplasias Pancreáticas/diagnóstico , Injúria Renal Aguda/diagnóstico , Injúria Renal Aguda/patologia , Injúria Renal Aguda/cirurgia , Adenoma de Células das Ilhotas Pancreáticas/patologia , Adenoma de Células das Ilhotas Pancreáticas/cirurgia , Adulto , Idoso , Desidratação/patologia , Desidratação/cirurgia , Feminino , Humanos , Hipopotassemia/diagnóstico , Hipopotassemia/patologia , Hipopotassemia/cirurgia , Masculino , Microscopia Eletrônica , Pessoa de Meia-Idade , Pancreatectomia , Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas/cirurgia , SíndromeAssuntos
Neurônios/efeitos dos fármacos , Reserpina/farmacologia , Sistema Nervoso Simpático/efeitos dos fármacos , Animais , Di-Hidroxifenilalanina/farmacologia , Iproniazida/farmacologia , Masculino , Metildopa/farmacologia , Metiltirosinas/farmacologia , Inibidores da Monoaminoxidase/farmacologia , Norepinefrina/biossíntese , Ratos , Serotonina/farmacologia , Tetrabenazina/farmacologia , Fatores de Tempo , Tranilcipromina/farmacologia , Ducto Deferente/efeitos dos fármacosAssuntos
Doença de Parkinson Secundária/induzido quimicamente , Animais , Atropina/uso terapêutico , Benzotropina/farmacologia , Butirofenonas/farmacologia , Gatos , Clorpromazina/farmacologia , Relação Dose-Resposta a Droga , Eletromiografia , Neurônios Motores/efeitos dos fármacos , Doença de Parkinson/tratamento farmacológico , Fenotiazinas/farmacologia , Coelhos , Ratos , Reserpina/antagonistas & inibidores , Tétano/induzido quimicamente , Fatores de Tempo , Tremorina/farmacologia , Trifluoperazina/farmacologiaAssuntos
Compostos de Anilina/metabolismo , Magnésio/farmacologia , Microssomos Hepáticos/enzimologia , NADP/metabolismo , Aminopirina/metabolismo , Animais , Citocromos/análise , Deficiências Nutricionais/enzimologia , Deficiências Nutricionais/metabolismo , Dieta , Técnicas In Vitro , Masculino , Microssomos Hepáticos/análise , Nitrobenzenos/metabolismo , Oxirredutases/metabolismo , Pentobarbital/metabolismo , Proteínas/análise , RNA/análise , RatosAssuntos
Deficiências Nutricionais/metabolismo , Microssomos Hepáticos/metabolismo , Zinco , Aminopirina/metabolismo , Compostos de Anilina/metabolismo , Animais , Ácido Ascórbico/urina , Benzoatos/metabolismo , Citocromos/análise , Citocromos/metabolismo , Dieta , Técnicas In Vitro , Masculino , Microssomos Hepáticos/análise , Pentobarbital/metabolismo , Proteínas/análise , Proteínas/metabolismo , RNA/análise , RNA/metabolismo , Ratos , Sono/efeitos dos fármacos , Fatores de Tempo , Zoxazolamina/metabolismoAssuntos
Proteínas Alimentares , Grão Comestível , Produtos Pesqueiros , Fenômenos Fisiológicos da Nutrição , Animais , Cistina , Farinha , Lisina , Metionina , Leite , Oryza , Ratos , Treonina , TriticumAssuntos
Promoção da Saúde , Saúde Pública/tendências , Canadá , Previsões , Humanos , Morbidade , Meio Social , TecnologiaRESUMO
The graft-versus-host (GVH) reactivity of uremic and control spleen cells was studied by popliteal lymph node assay in the rat. The reaction evoked by cells from animals with severe uremia was conspicuously weaker than that evoked by control cells. The magnitude of the GVH reaction induced by control cells was directly proportional to dose, while with the uremic cells the same increases in dose led only to insignificant increases in the strength of the GVH reaction. When mixtures of syngeneic control and uremic cells were used, the GVH reactivity of the control cells was suppressed. The activity of uremic spleen cells can be enhanced (restored) by removal of the sub-population of cells adherent to glass wool. The GVH reaction induced by uremic cells so treated became directly proportional to dose. The removal of the adherent cell population from the uremic spleen cell suspension also led to the disappearance of the suppressor effect in mixtures of control and uremic cells. These results indicate that a decrease in GVH activity of rat uremic spleen cells is due to an increase in suppressor cell activity in the uremic spleen cell population.
Assuntos
Reação Enxerto-Hospedeiro , Baço/imunologia , Uremia/imunologia , Animais , Bioensaio , Adesão Celular , Masculino , Ratos , Ratos Endogâmicos BN , Ratos Endogâmicos Lew , Baço/citologia , Supressão Genética , Uremia/etiologiaRESUMO
Epon-Araldite sections supported on Formvar-coated slot grids can be stabilized by exposing the area of interest in the column of the electron microscope to irradiation of 0-5C/cm-2. With this procedure one can obtain electron micrographs of high quality, without drift or distortion, from any part of the open slot area. After treatment the support film is not only stable and transparent but robust enough to permit repeated removal and replacement of the specimen in the microscope column. We illustrate the method with a series of electron micrographs with initial magnifications ranging from x300 to x500,000 to show the quality of image that can be achieved. The effect of the irradiation on tissue architecture is checked by resectioning the irradiated sections. We recommend this method of local irradiation of sections for investigations using low or intermediate magnifications for the wide field it permits, for the durability it confers on the specimen and for its convenience.
Assuntos
Técnicas Histológicas , Microscopia Eletrônica/métodos , Membrana Celular/ultraestrutura , Elétrons , Resinas Epóxi , Estudos de Avaliação como Assunto , Humanos , Glomérulos Renais/ultraestrutura , Metacrilatos , Efeitos da RadiaçãoRESUMO
The effects of the serum of rats with experimentally induced chronic renal failure and of the supernatant of cultured spleen cells obtained from these animals were tested in the mixed lymphocyte reaction (MLR). Serum of uremic rats with blood urea nitrogen levels greater than 35 mg. per 100 ml. and supernatant of spleen cultures from animals with blood urea nitrogen levels greater than 60 mg. per 100 ml. were found to be inhibitory to the MLR. The inhibitory activity of uremic serum was directly correlated with blood urea nitrogen levels. The inhibitory activities both of uremic serum and of the supernatant of cultured uremic spleen cells were further studied and compared. Dialysis in vitro does not remove the suppressing effect of serum or of supernatant on the MLR. Irreversible inhibition of the MLR is observed after 48 hours' exposure to the serum or to the supernatant; this inhibition occurs whether the MLR culture is exposed during the first 48 hours or last 48 hours of incubation. In some uremic rats the inhibitory activity of the serum disappears or is weakened after splenectomy, despite a continued rise in blood urea nitrogen levels.