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1.
Am J Surg Pathol ; 25(8): 1079-85, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11474294

RESUMEN

Most studies on the risk of cancer after high-grade prostatic intraepithelial neoplasia (PIN) on biopsy have been small (fewer than 100 men), have not analyzed in detail if histologic features can predict cancer, and have not assessed the risk of cancer with multiple repeat biopsies. We analyzed 245 men in whom the only abnormal finding on the initial biopsy was high-grade PIN and who had at least one follow-up biopsy. Repeat biopsy identified cancer in 32.2% of men. If only one follow-up biopsy had been performed on the 245 men, only 24.5% of men would have been found to have cancer. The only independent histologic predictor of a cancer diagnosis was the number of cores with high-grade PIN; risk of cancer: 30.2% with 1 or 2 cores, 40% with 3 cores, and 75% with >3 cores. The following did not predict cancer: number of high-grade PIN glands, maximum percentage of gland involved by high-grade PIN, nucleolar prominence, percentage of cells with prominent nucleoli, pattern of high-grade PIN (flat, tufting, micropapillary, cribriform), marked pleomorphism, digital rectal examination, transrectal ultrasound findings, family history of prostate cancer, serum prostate specific antigen (PSA) at time of high-grade PIN diagnosis, and rate of change of serum PSA. Eighty-one (33%) men had more than one follow-up biopsy; in these cases the following findings on the original high-grade PIN biopsy predicted cancer: the presence of mitoses, the number of positive cores, predominant micropapillary and cribriform high-grade PIN, and very large prominent nucleoli. Of 81 men with more than one follow-up biopsy, if the first repeat biopsy were benign, high-grade PIN, or atypical, the eventual cancer rate was 10%, 25.9%, and 57.1%, respectively (p = 0.002). Of 15 men with more than two repeat biopsies, only two (13.3%) had cancer. In summary, approximately one third of men with high-grade PIN on biopsy have cancer on follow-up. If cancer is not found on the first two follow-up biopsies, it will unlikely be found. Although clinical findings at the time of diagnosis of high-grade PIN are not useful to predict who might have cancer, histologic findings may help identify who needs additional biopsies.


Asunto(s)
Adenocarcinoma/patología , Neoplasia Intraepitelial Prostática/patología , Neoplasias de la Próstata/patología , Adenocarcinoma/sangre , Anciano , Anciano de 80 o más Años , Biopsia con Aguja , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Antígeno Prostático Específico/sangre , Neoplasia Intraepitelial Prostática/sangre , Neoplasias de la Próstata/sangre
2.
J Orthop Trauma ; 15(5): 326-32, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11433136

RESUMEN

OBJECTIVE: To evaluate the changes in the articular cartilage and subchondral bone after an osteotomy designed to simulate an articular fracture. DESIGN: The contribution of the cartilage and subchondral bone was evaluated twelve weeks after creating a 1.0-millimeter step-off in the medial plateau of the tibia of twelve adult domestic sheep. All animals surviving were labeled with fluorescent markers for bone production, oxytetracycline (fifty milligrams per kilogram), and calcein (twelve milligrams per kilogram) nine and 11.5 weeks after surgery. The knees were loaded in compression using an Instron materials tester with pressure-sensitive film to record joint contact pressures above and below the medial meniscus. SETTING: The studies were performed in the research laboratories of the Orthopaedic Laboratory at Harborview Medical Center in Seattle, Washington and the Madigan Army Medical Center in Tacoma, Washington. ANIMALS: Twelve adult domestic sheep. INTERVENTION: An intraarticular osteotomy of the medial tibial plateau with 1.0 millimeter of displacement was performed. The osteotomy was stabilized with 3.5-millimeter lag screws. MAIN OUTCOME MEASURES: The contact pressures of the knee joint and articular histology were evaluated twelve weeks after surgery. Samples of the articular cartilage were analyzed by light microscopy and electron microscopy to evaluate the response of the articular cartilage and subchondral bone of the differential joint loading because of the irregularity in the articular surface caused by the osteotomy. RESULTS: The knees with an intraarticular step-off had two major contact areas with an intervening zone of reduced load corresponding to the edge of the depressed fragment. Coronal histologic sections through the articular surface showed the presence of thinning and fibrillation on the high side of the step-off and some compensatory hypertrophy of the cartilage. The subchondral bone was not responsible for restoring articular congruity because the rate of bone production was similar between the low side of the articular fracture (1.85 micrometers per day) and the high side of the fracture (1.67 micrometers per day). Scanning electron microscopy showed partial cartilage remodeling by deformation of the high side cartilage with bending of the vertical collagen fibrils, even in the unloaded state. CONCLUSIONS: In this model with a small fracture displacement (1.0 millimeter), which was less than the thickness of the articular cartilage (1.5 millimeters), the contour of the joint improved despite residual articular surface incongruency after the fracture healing.


Asunto(s)
Cartílago/metabolismo , Fijación Interna de Fracturas/métodos , Curación de Fractura , Modelos Anatómicos , Osteotomía , Fracturas de la Tibia/cirugía , Animales , Microscopía Electrónica de Rastreo , Radiografía , Ovinos , Fracturas de la Tibia/diagnóstico por imagen
3.
Am J Surg Pathol ; 25(6): 802-8, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11395559

RESUMEN

Nephrogenic adenoma, thought to be a benign metaplastic response of the urothelium to injury, can rarely affect the prostatic urethra. Extension of small tubules of nephrogenic adenoma into the underlying prostatic fibromuscular stroma can lead to the misdiagnosis of prostatic adenocarcinoma in transurethral resection specimens and prostate biopsies. We reviewed 26 cases of nephrogenic adenoma involving the prostatic urethra, seen at The Johns Hopkins Hospital from 1990 to 1998, to evaluate the histologic features, which may better define this lesion. Immunohistochemical results were evaluated for cases where the lesion was present on deeper sections. Histologic patterns included the following: tubules in 96% (25 of 26), structures resembling vessels in 73% (19 of 26), cords and individual cells in 46% (12 of 26), papillary configurations in 19% (5 of 26), and signet ring cell-like tubules in 12% (3 of 26). Other features of nephrogenic adenoma, such as thyroidization, were identified in 38% (10 of 26), and peritubular sheaths were seen in 65% (17 of 26) of cases. Nucleoli were prominent in 54% (14 of 26), and no case had mitoses. In the region of nephrogenic adenoma, urothelium was noted in 69% (18 of 26); in 61% (11 of 18) it showed cuboidal metaplasia and 28% (5 of 18) showed squamous metaplasia. Extension of nephrogenic adenoma into muscle was observed in 77% (20 of 26) of cases, 75% (15 of 20) of which had identifiable urothelium overlying the lesion. Blue-tinged mucinous secretions were observed in 32% (8 of 25) of cases. Inflammation was found in all but one case. Nephrogenic adenomas were diffusely positive for 34betaE12 in 11% (1 of 9) of cases, focally positive in 44% (4 of 9), and negative in 44% (4 of 9). In 100% (9 of 9), cytokeratin 7 stains were positive. Focal prostate specific antigen and PSAP positivity were seen in 36% (4 of 11) and 50% (5 of 10) of nephrogenic adenoma cases, respectively. In conclusion, nephrogenic adenoma of the prostatic urethra can mimic prostate cancer because of: 1) the presence of tubules, cords, and signet ring-like tubules; 2) prominent nucleoli; 3) muscle involvement; 4) blue-tinged mucinous secretions; 5) focal prostate specific antigen and PSAP positivity; and 6) negative staining in some cases for 34betaE12. Features useful in the diagnosis of nephrogenic adenoma include the following: 1) distinctive nephrogenic patterns, such as papillary and "vascular," 2) adjacent urothelium, 3) thyroidization, 4) peritubular sheaths, 5) associated inflammation, and 6) positivity for cytokeratin 7 and, in some cases, 34betaE12.


Asunto(s)
Adenocarcinoma/patología , Adenoma/patología , Neoplasias de la Próstata/patología , Neoplasias Uretrales/patología , Adulto , Anciano , Diagnóstico Diferencial , Humanos , Masculino , Persona de Mediana Edad
4.
J Am Acad Orthop Surg ; 9(2): 128-36, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11281636

RESUMEN

Kienbock's disease, or osteonecrosis of the lunate, can lead to chronic, debilitating wrist pain. Etiologic factors include vascular and skeletal variations combined with trauma or repetitive loading. In stage I Kienbock's disease, plain radiographs appear normal, and bone scintigraphy or magnetic resonance imaging is required for diagnosis. Initial treatment is nonoperative. In stage II, sclerosis of the lunate, compression fracture, and/or early collapse of the radial border of the lunate may appear. In stage IIIA, there is more severe lunate collapse. Because the remainder of the carpus is still uninvolved, treatment in stages II and IIIA involves attempts at revascularization of the lunate-either directly (with vascularized bone grafting) or indirectly (by unloading the lunate). Radial shortening in wrists with negative ulnar variance and capitate shortening or radial-wedge osteotomy in wrists with neutral or positive ulnar variance can be performed alone or with vascularized bone grafting. In stage IIIB, palmar rotation of the scaphoid and proximal migration of the capitate occur, and treatment addresses the carpal collapse. Surgical options include scaphotrapeziotrapezoid or scaphocapitate arthrodesis to correct scaphoid hyperflexion. In stage IV, degenerative changes are present at the midcarpal joint, the radiocarpal joint, or both. Treatment options include proximal-row carpectomy and wrist arthrodesis.


Asunto(s)
Osteocondritis/diagnóstico , Osteocondritis/terapia , Huesos del Carpo/diagnóstico por imagen , Huesos del Carpo/patología , Humanos , Imagen por Resonancia Magnética , Osteocondritis/etiología , Osteocondritis/cirugía , Radiografía
6.
Hand Clin ; 16(1): 67-72, 2000 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-10696577

RESUMEN

Age and mechanism of injury, both out of the control of the surgeon, seem to be the prime determinants of functional outcome following nerve repair. Careful application of the principles of nerve repair can ensure that the appropriate method of repair--primary, secondary, or nerve graft--is selected, and this may be the best way to increase the chances for a successful result.


Asunto(s)
Traumatismos de los Nervios Periféricos , Nervios Periféricos/cirugía , Humanos , Nervio Mediano/lesiones , Nervio Mediano/cirugía , Nervio Radial/lesiones , Nervio Radial/cirugía , Resultado del Tratamiento , Nervio Cubital/lesiones , Nervio Cubital/cirugía
7.
J Hand Surg Am ; 25(1): 61-76, 2000 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-10642474

RESUMEN

Qualitative and quantitative outcomes were assessed clinically and radiographically in 41 patients (46 thumbs) with thumb basal joint arthritis limited to the trapeziometacarpal joint treated with hemiresection arthroplasty of the trapezium, flexor carpi radialis ligament reconstruction, and allograft costochondral interposition graft. Results of the validated Disability of Arm, Shoulder, and Hand questionnaire at a mean follow-up time of 42 months (range, 24-48 months) revealed that 90% of the patients had a high level of function with minimal symptoms. Important improvements in web space with increased palmar and radial abduction and grip and pinch strength measurements were observed. The trapeziometacarpal space had decreased 21% after surgery while trapeziometacarpal subluxation was 16% compared with 21% before surgery. There was an inverse correlation between the loss of trapezial height and subluxation and clinical outcome. The results of this study demonstrate that although the preoperative trapezial height was not maintained, the reconstructed thumbs remained stable, with little subluxation and improved clinical outcomes. (J Hand Surg 2000; 25A:61-76.


Asunto(s)
Artritis/cirugía , Huesos del Carpo/cirugía , Cartílago/trasplante , Ligamentos Articulares/cirugía , Articulación Metacarpofalángica/cirugía , Procedimientos de Cirugía Plástica/métodos , Pulgar/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Artritis/diagnóstico por imagen , Huesos del Carpo/diagnóstico por imagen , Femenino , Estudios de Seguimiento , Humanos , Ligamentos Articulares/diagnóstico por imagen , Masculino , Articulación Metacarpofalángica/diagnóstico por imagen , Persona de Mediana Edad , Radiografía , Procedimientos de Cirugía Plástica/estadística & datos numéricos , Costillas , Pulgar/diagnóstico por imagen , Trasplante Homólogo , Resultado del Tratamiento
8.
Dig Dis Sci ; 41(6): 1088-98, 1996 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-8654139

RESUMEN

Barrett's esophagus is a metaplastic condition in which the normal stratified squamous epithelium of the distal esophagus is replaced by columnar epithelium. Our group has previously characterized a unique surface cell (the "distinctive cell") at the junction of squamous and Barrett's epithelium. This cell is notable for the simultaneous presence on its surface of both squamous and columnar cell features. The aims of our present study were, first, to evaluate prospectively the frequency with which Barrett's patients have the distinctive cell at the squamo-Barrett's junction; second, to further elucidate the characteristics of the distinctive cell; and third, to perform a combined morphological study of the squamo-Barrett's junction using scanning electron microscopy followed by transmission and light microscopy. We divided study patients into two groups: Group I consisted of Barrett's patients and group II of non-Barrett's control patients. Of eight group I Barrett's patients with junctional biopsies, three were noted to have the distinctive cell (37.5%). In contrast, this cell was not observed in any of the group II control patients. Biopsies in control patients as well as Barrett's patients without the distinctive cell revealed abrupt squamogastric or squamo-Barrett's junctions by scanning electron microscopy and light microscopy. In contrast, biopsies from the Barrett's patients with the distinctive cell revealed junctions that were not abrupt and had the distinctive cells overlying normal squamous epithelium. By scanning electron microscopy, the distinctive cells were flattened, polygonal cells with surface microvilli (a columnar cell feature) and were demarcated from one another by shallow depressions, or by intercellular ridges (a squamous cell feature). By transmission electron microscopy, the distinctive cells were cuboidal in shape with abundant apical microvilli and secretory vesicles. We have confirmed that distinctive cells are present in some Barrett's patients. This cell is a morphologic hybrid, sharing features of both squamous and columnar cells, and may be analogous to hybrid cells identified in other locations that undergo metaplasia (eg, the human cervix). Its origin may be the result of transformation of multipotential basal cells of squamous epithelial origin. We hypothesize that the distinctive cells may represent an intermediate stage in the development of Barrett's epithelium.


Asunto(s)
Esófago de Barrett/patología , Unión Esofagogástrica/ultraestructura , Adulto , Anciano , Epitelio/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos
9.
Gastroenterology ; 104(3): 698-708, 1993 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-8440430

RESUMEN

BACKGROUND: It is generally believed that M cells do not modify the antigens they transport from the intestinal lumen to underlying immunocompetent cells because it has been reported that M cells contain few elements of the lysosomal system. METHODS: We used specific cytochemical and immunocytochemical probes to examine whether M cells in jejunal Peyer's patches of adult rats contain the requisite intracellular components to process and potentially present endocytosed antigens. RESULTS: M cells contained acid phosphatase-enriched prelysosomelike and lysosomelike structures. A basic congener of dinitrophenol, which concentrates in acidic cell compartments, is localized following its instillation into Peyer's patch-containing ligated jejunal loops to the endosomal-lysosomal system of M cells. Prelysosomelike and lysosomelike structures in ultrathin cryosections of M cells reacted with polyclonal antibody to a membrane glycoprotein (lgp120) enriched in prelysosomes and lysosomes. Using monoclonal antibody OX6 as a probe, M cells expressed the major histocompatibility complex (MHC) class II determinant, Ia, on the basolateral plasma membrane and in organelles with structural features of endosomes, prelysosomes, and lysosomes. Expression was enhanced by pretreatment with interferon gamma. CONCLUSIONS: M cells possess acidic endosomal and acid phosphatase-containing prelysosomal and lysosomal compartments and express MHC class II determinants. Hence, M cells may have the capacity to process and present endocytosed antigens to adjacent intraepithelial T lymphocytes.


Asunto(s)
Antígenos de Histocompatibilidad Clase II/análisis , Yeyuno/inmunología , Lisosomas/metabolismo , Ganglios Linfáticos Agregados/inmunología , Fosfatasa Ácida/análisis , Adamantano/análogos & derivados , Adamantano/metabolismo , Animales , Endocitosis , Femenino , Glicoproteínas/análisis , Antígenos de Histocompatibilidad Clase II/inmunología , Yeyuno/metabolismo , Yeyuno/ultraestructura , Ganglios Linfáticos Agregados/metabolismo , Ganglios Linfáticos Agregados/ultraestructura , Ratas , Ratas Sprague-Dawley
10.
J Immunol ; 147(8): 2518-24, 1991 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-1717564

RESUMEN

The human CD1 locus encodes three nonpolymorphic MHC class I-like cell surface glycoproteins, CD1a-c, which are expressed primarily by immature thymocytes. A mAb and antipeptide antiserum were utilized to determine the tissue distribution of a fourth CD1 molecule, CD1d. Within the lymphoid lineage, CD1d was expressed on B cells but not on thymocytes. Immunoperoxidase staining of fresh frozen intestinal tissues demonstrated that the majority of intestinal epithelial cells, with the exception of cells at the base of some crypts, expressed CD1d. The CD1d staining was observed in the cytoplasm and along the basolateral membranes of the epithelial cells. The intestinal epithelial cell expression of CD1d was confirmed by immunoblotting with a CD1d antipeptide antiserum. Further immunoperoxidase studies indicated that CD1d, unlike murine CD1, was also expressed by nonlymphoid tissues outside of the gastrointestinal tract. The expression of CD1d outside the lymphoid and myeloid lineages clearly distinguishes this molecule from CD1a-c and suggests that it may serve a distinct function. The prominent expression of CD1d by intestinal epithelial cells suggests that this molecule may be an important ligand for T lymphocytes within the gut-associated lymphoid tissue.


Asunto(s)
Antígenos CD/análisis , Intestinos/inmunología , Animales , Anticuerpos Monoclonales/inmunología , Antígenos CD/inmunología , Antígenos CD/fisiología , Antígenos CD1 , Epitelio/inmunología , Humanos , Sueros Inmunes/inmunología , Linfocitos/inmunología , Ratones , Pruebas de Precipitina , Ratas , Receptores de Antígenos de Linfocitos T alfa-beta/análisis , Microglobulina beta-2/análisis
11.
Gastroenterology ; 100(5 Pt 1): 1172-9, 1991 May.
Artículo en Inglés | MEDLINE | ID: mdl-2013366

RESUMEN

Intravenously injected sheep antilaminin immunoglobulin G conjugated with horseradish peroxidase uniformly labeled the basement membrane of mouse villus epithelium but not that of Peyer's patch follicle domes, although laminin is abundant in both. This suggested differences in the permeability of capillaries underlying these epithelia. Therefore, the fine structure of mouse subepithelial villus and follicle capillaries and their permeability to selected macromolecules was compared. Fenestrae, abundant in villus capillaries, were extremely rare in dome capillaries as assessed by electron microscopy of tissue sections and freeze-fracture replicas. Two minutes after IV-injected horseradish peroxidase and 9 minutes after IV-injected hemoglobin, reaction product decorated the pericapillary space of 97% and 95%, respectively, of capillary profiles in the upper half of villi but only 28% and 2%, respectively, of capillary profiles in the upper half of patch domes. Reaction product was intense surrounding most villus capillaries but, when present, was faint in dome capillary adventitia. These results indicate that most subepithelial capillaries in mouse Peyer's patch domes, unlike those in villi, generally lack endothelial fenestrae, and the dome capillary network is less permeable to some macromolecules than that of the villus.


Asunto(s)
Capilares/ultraestructura , Permeabilidad Capilar/fisiología , Mucosa Intestinal/irrigación sanguínea , Ganglios Linfáticos Agregados/irrigación sanguínea , Animales , Membrana Basal/química , Membrana Basal/ultraestructura , Endotelio Vascular/ultraestructura , Hemoglobinas/farmacocinética , Peroxidasa de Rábano Silvestre , Inmunoglobulina G , Mucosa Intestinal/ultraestructura , Laminina/análisis , Ratones , Ratones Endogámicos BALB C , Ganglios Linfáticos Agregados/inmunología , Ganglios Linfáticos Agregados/ultraestructura
12.
J Clin Invest ; 86(1): 87-95, 1990 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-2195064

RESUMEN

Little is known regarding turnover of the epithelial basement membrane in adult small intestine. Are components degraded and inserted along the length of the crypt-villus axis or selectively in the crypt region with subsequent migration of basement membrane from crypt to villus tip in concert with epithelium? We injected affinity-purified sheep anti-laminin IgG or sheep anti-laminin IgG complexed to horseradish peroxidase (HRP) into mice to label basement membrane laminin in vivo. Fluorescence microscopy revealed linear fluorescence along the length of the jejunal epithelial basement membrane 1 d after anti-laminin IgG injection. By 1 wk, small nonfluorescent domains were interposed between larger fluorescent domains. Over the next 5 wk the lengths of nonfluorescent domains increased progressively whereas those of fluorescent domains decreased. Additionally, electron microscopy revealed HRP reaction product along the length of the epithelial basement membrane after 1 d whereas unlabeled or lightly labeled domains that increased in length with time were observed interposed between heavily labeled domains by 2 and 4 wk along the entire crypt-villus axis. We conclude that laminin turnover occurs focally in the epithelial basement membrane of mouse jejunum along the crypt-villus axis over a period of weeks and that this basement membrane does not comigrate in concert with its overlying epithelium.


Asunto(s)
Membrana Basal/metabolismo , Mucosa Intestinal/metabolismo , Yeyuno/metabolismo , Laminina/metabolismo , Animales , Epitelio/metabolismo , Técnica del Anticuerpo Fluorescente , Masculino , Ratones , Ratones Endogámicos BALB C , Microscopía Electrónica , Factores de Tiempo
13.
Gastroenterology ; 97(5): 1193-204, 1989 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-2792657

RESUMEN

That microvilli of intestinal absorptive cells in the duodenum and jejunum are disrupted by acute challenge with lectins contained in raw kidney beans (RKB) was shown nearly 10 yr ago by light microscopy. However, the precise morphologic damage produced by RKB has not been characterized, and it is not known whether microvilli, once damaged, undergo repair. We have examined these issues by challenging rats with suspensions of 300 mg of RKB, boiled beans, or standard laboratory chow by orogastric lavage. Microvillus length was measured in electron micrographs from 6 to 20 h after challenge. Epithelial cell migration was determined by autoradiography after injection of [3H]thymidine. After challenge with RKB, microvilli (a) showed extensive vesiculation along the length of villi 2-4 h after challenge; (b) were reduced significantly in length along the entire villus 6 h after challenge; and (c) were near normal in length by 20 h after challenge. Microvillus length was also reduced significantly 6 h after challenge with boiled beans. The rate of cell migration was not accelerated by treatment with RKB. These data suggest that damage to microvilli caused by 300 mg of RKB is self-limited and reversible; microvilli once damaged by RKB are repaired. Repair of microvilli is due to intrinsic reparative processes rather than accelerated replacement of damaged cells. We speculate that microvilli may be repeatedly damaged and repaired after ingestion of dietary lectins.


Asunto(s)
Yeyuno/efectos de los fármacos , Fitohemaglutininas/toxicidad , Animales , Movimiento Celular , Absorción Intestinal , Yeyuno/ultraestructura , Masculino , Microscopía Electrónica , Microvellosidades/efectos de los fármacos , Ratas , Ratas Endogámicas
14.
Anat Rec ; 219(1): 69-77, 1987 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-3688463

RESUMEN

Tuft cells are present in most columnar epithelia derived from endoderm including the small intestine. They are characterized by long, wide apical microvilli and an extensively developed cytoplasmic tubulovesicular system. We examined in detail the structural features of the apical plasma membrane of small intestinal tuft cells from adult guinea pigs, rats, and adult and suckling mice with freeze-fracture and conventional transmission electron microscopy methods and utilized cationized ferritin and horseradish peroxidase as tracers to determine whether tuft cells endocytose macromolecules. The microvillus membrane of intestinal tuft cells has few P-face intramembrane particles, displays little alkaline phosphatase activity, and is highly enriched in cholesterol. Tuft cell tight junctions resemble those of absorptive cells in strand count and strand-to-strand crosslinks but, unlike those of absorptive cells, they display many abluminal free-ending strands. Tuft cells of adult and suckling mouse intestine show no evidence of internalization of cationized ferritin or, in suckling mice, uptake of horseradish peroxidase. We conclude that the microvillus membrane of small intestinal tuft cells is protein-poor but cholesterol-rich and that small intestinal tuft cells do not endocytose macromolecules in bulk from the intestinal lumen.


Asunto(s)
Intestino Delgado/citología , Animales , Membrana Celular/ultraestructura , Ferritinas , Técnica de Fractura por Congelación , Cobayas , Peroxidasa de Rábano Silvestre , Intestino Delgado/ultraestructura , Ratones , Microscopía Electrónica , Microvellosidades/ultraestructura , Ratas , Ratas Endogámicas
15.
Cell Tissue Res ; 248(3): 709-11, 1987 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-3607856

RESUMEN

The terminal web (TW) region of mature absorptive cells in the small intestine of the rat contains an elaborate cytoskeleton which supports the apical microvillus membrane. In studies regarding the structural organization of the cytoskeleton and associated proteins in the small intestine, microtubules have not been mentioned as components of the TW. By transmission electron microscopy of conventional resin-embedded sections of rat small intestine, we observe many microtubule profiles in the TW of mature absorptive cells. These microtubules are found in various orientations, although most course parallel to the long axis of the cell, and many microtubule profiles are seen in close association with smooth-surfaced vesicles.


Asunto(s)
Yeyuno/citología , Microtúbulos/ultraestructura , Animales , Citoesqueleto/ultraestructura , Absorción Intestinal , Mucosa Intestinal/citología , Mucosa Intestinal/ultraestructura , Yeyuno/ultraestructura , Masculino , Microscopía Electrónica , Microvellosidades/ultraestructura , Ratas , Ratas Endogámicas
16.
Gastroenterology ; 92(1): 13-22, 1987 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-3781180

RESUMEN

Impairment of the mucosal microcirculation may contribute to ethanol-induced gastric mucosal damage. In this report, we describe diffuse and severe ultrastructural damage to the capillaries of the gastric glandular mucosa of the rat that occurred within 1 min after intragastric instillation of 100% ethanol. There was a gradient of damage in that endothelial cell structure was most severely disrupted in profiles of capillaries located close to the luminal surface but some morphologic evidence of damage was evident in the wall of capillary profiles to a mean depth of 256 micron. Capillary structure was generally normal in the deeper regions of the mucosa. Pretreatment with intragastric cysteamine, 30 mg/100 g, or intragastric prostaglandin F2 beta, 0.5 mg/100 g, significantly reduced the depth in the mucosa to which damage to capillaries extended. Pretreatment with intragastric prostaglandin F2 beta, 0.2 mg/100 g, afforded no significant protection. We conclude that a 1-min exposure to 100% ethanol induces striking damage to the microcirculation of glandular mucosa of the rat stomach with severe damage to capillary profiles near the lumen and sparing of capillary profiles near the muscularis mucosa, and pretreatment with the sulfhydryl agent, cysteamine, or with a large dose of prostaglandin F2 beta reduces the extent of but does not abolish ethanol-induced damage to gastric mucosal capillaries.


Asunto(s)
Cisteamina/farmacología , Etanol/toxicidad , Mucosa Gástrica/efectos de los fármacos , Prostaglandinas F/farmacología , Animales , Capilares/ultraestructura , Femenino , Mucosa Gástrica/irrigación sanguínea , Premedicación , Ratas , Ratas Endogámicas
17.
Gastroenterology ; 91(6): 1401-14, 1986 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-3533700

RESUMEN

Absorptive cells of the small intestine are highly polarized cells with distinct microvillus membrane (MVM) and basolateral plasma membrane domains. We compared membrane structure in the following preparations of rat small intestine commonly used for in vitro study of MVM function: epithelial sheets, isolated epithelial cells, and four different MVM vesicle preparations, using electron microscopy of thin sections and freeze fracture replicas. We also quantitated mean vesicle diameter of the four MVM preparations by quasielastic light scattering and determined their actin content. Epithelial sheets maintained their plasma membrane polarity as judged by intramembrane particle (IMP) distribution for at least 30 min after isolation. In contrast, the plasma membrane of isolated cells showed redistribution of IMPs, indicating considerable loss of polarity in the few minutes required for cell recovery. The P-face IMPs in MVM prepared by Ca++ precipitation were randomly distributed but became aggregated after exposure to potassium thiocyanate, which removed approximately 50% of core actin. The P-face IMPs in Mg++ precipitated MVM were aggregated whether or not core actin was depleted with potassium thiocyanate. The shape and size of MVM vesicles differed considerably with different preparative techniques. The extremely rapid loss of plasma membrane polarity of isolated intestinal epithelial cells and the striking structural heterogeneity of MVM vesicles prepared by commonly used techniques should be considered in the interpretation of functional studies with these preparations.


Asunto(s)
Intestino Delgado/ultraestructura , Animales , Membrana Celular/ultraestructura , Epitelio/ultraestructura , Técnica de Fractura por Congelación , Técnicas Histológicas , Absorción Intestinal , Masculino , Microscopía Electrónica , Microscopía Electrónica de Rastreo , Microvellosidades/ultraestructura , Ratas , Ratas Endogámicas
18.
Gastroenterology ; 86(5 Pt 1): 789-801, 1984 May.
Artículo en Inglés | MEDLINE | ID: mdl-6706062

RESUMEN

The derivation of membranous epithelial (M) cells, which are specialized antigen sampling cells overlying the lymphoid follicles of Peyer's patches, is unknown; it has been suggested recently, however, that M cells differentiate from absorptive cells on the follicular epithelium. To examine whether M cells, like other intestinal epithelial cells, derive directly from undifferentiated crypt cells, we studied the structure, selected functional features, proliferation, and distribution of Peyer's patch M cells in the ileum of adult mice. We observed a spectrum of M-cell structure ranging from mature to immature-appearing M cells. Most immature-appearing M cells lacked the central cytoplasmic hollow found in those mature M cells that contained lymphoid cells. The microvilli of immature-appearing M cells were more numerous and regular appearing than those of mature M cells, but they were sparser and shorter, and some were wider than those of absorptive cells. Many immature-appearing M cells contained more free ribosomes than did mature M cells. Both mature and immature-appearing M cells were observed on all regions of follicular domes, including the base near the mouths of surrounding crypts. Type 1 reovirions adhered with considerable selectivity to the apical membrane of mature and immature-appearing M cells but were observed in endocytic vesicles only in mature M cells. Neither mature nor immature-appearing M cells showed evidence of lipid absorption, in contrast to adjacent absorptive cells. Both mature and immature-appearing M cells internalized more bound cationized ferritin than did absorptive cells. Only mature M cells transported cationized ferritin to the intercellular spaces. Nuclei of a few immature-appearing M cells were labeled 24 h after injection of [3H]thymidine in concert with the appearance of labeled absorptive cell nuclei. These observations strongly suggest that many, if not all, M cells derive directly from undifferentiated crypt cells.


Asunto(s)
Tejido Linfoide/ultraestructura , Ganglios Linfáticos Agregados/ultraestructura , Animales , Diferenciación Celular , Epitelio/ultraestructura , Ferritinas , Íleon/ultraestructura , Metabolismo de los Lípidos , Ratones , Ratones Endogámicos BALB C , Microvellosidades/ultraestructura , Ganglios Linfáticos Agregados/metabolismo , Ganglios Linfáticos Agregados/microbiología , Reoviridae
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