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M J Becich

Publications and source records attributed to M J Becich.

At least 55 records · Page 3Linked to original sources
PubMed1995

Cathepsin L mediates intracellular ileal digestion of gastric intrinsic factor.

Although acidic proteases of lysosomal origin are implicated in the degradation of intrinsic factor (IF) during cobalamin (cbl) transport across enterocytes and proximal renal tubule cell lines, the enzyme(s) involved in this process is not known. Recombinant (baculovirus-produced) rat 125I-labeled IF (125I-rIF), 43 kDa, added in vivo to the lumen of rat ileum was converted intracellularly to peptides of 33 and 26 kDa. In vitro rat 125I-rIF was degraded to peptides of 33 and 31 kDa by addition of cathepsin L; this conversion was fully inhibited by leupeptin. Western blot analysis using antiserum against denatured native rat IF identified additional cathepsin L degradation products in the 17- to 23-kDa range. In vitro the binding of cobalamin partially inhibited cathepsin L degradation of IF. Rat rIF produced from either insect (Sf9) or mammalian (CHO) cells and native rat IF were all degraded by cathepsin L, although the prominence of the various products differed in the recombinant preparations, being 33 and 36 kDa, respectively. Native rat IF was most sensitive to proteolysis, and no degradation products were identified. Rat 125I-rIF was taken up by LLC-PK1 cells, and 125I from degraded IF appeared abundantly on the basolateral side of cell monolayers by 1 h. The intracellular products of rat rIF in LLC-PK1 cells were the same size as those produced in vitro by the action of cathepsin L. Antiserum against a human kidney cDNA cathepsin L fusion protein easily demonstrated the protease in rat intestinal mucosa, as well as in all other tissues tested. These data suggest that cathepsin L is the protease responsible for the leupeptin-sensitive intracellular degradation of IF.

Animals↗
PubMed1994

Clearance of surfactant-like particle proteins from circulation in rats.

Surfactant-like particles (SLP) have been isolated from the apical surface of rat enterocytes but appear to arise within the enterocyte and to be secreted into neighboring lymphatics (K. DeSchryver-Kecskemeti, R. Eliakim, S. Carroll, W. F. Stenson, M. A. Moxley, and D. H. Alpers. J. Clin. Invest. 84: 1355-1361, 1989). The present study was undertaken to analyze the clearance and distribution of these particle-associated proteins in vivo in the rat. Labeling of particles isolated from apical scrapings of rat enterocytes with 125I enabled identification of proteins of 116, 92, 68, 58, 48, 31, and 25 kDa. After the intravenous administration of 125I-SLP, the trichloroacetic acid-precipitable radioactivity in the plasma disappeared in a biphasic pattern. The average half-life of the early phase was 7.5 min and the second phase was 75 min. The half-life of a subset of the proteins (116, 92, and 48 kDa) was shorter, measuring 4.5 min for the first phase and ranging from 20 to 52 min for the second phase. The amounts of labeled particle distributed to the liver, kidney, and spleen were much greater than could be accounted for by distribution in the extracellular space alone. The liver accounted for removal of approximately 50% of label in the first phase, with the kidney and spleen contributing 10 and 1%, respectively. Only 0.5 and 2.5% of labeled protein appeared in the bile and urine, respectively. The majority of labeled protein remaining in the serum after the initial phase of tissue uptake migrated at a density of 1.07-1.08, characteristic of intact particles, but slowly shifted to higher densities over 24 h. The maximum binding capacity was 56 nmol/mg membrane protein (Michaelis constant = 51 pM) using hepatic basolateral membranes. The particle was taken up into hepatocytes, as demonstrated by autoradiography. These data demonstrate the importance of the liver in clearing SLP from the blood in rats. The slow clearance of a portion of the particle protein provides support for the continued presence of these proteins in the serum of rats.

Animals↗
PubMed1994

A pathologist-designed imaging system for anatomic pathology signout, teaching, and research.

Pathology images are derived from gross surgical specimens, light microscopy, immunofluorescence, electron microscopy, molecular diagnostic gels, flow cytometry, image analysis data, and clinical laboratory data in graphic form. We have implemented a network of desktop personal computers (PCs) that allow us to easily capture, store, and retrieve gross and microscopic, anatomic, and research pathology images. System architecture involves multiple image acquisition and retrieval sites and a central file server for storage. The digitized images are conveyed via a local area network to and from image capture or display stations. Acquisition sites consist of a high-resolution camera connected to a frame grabber card in a 486-type personal computer, equipped with 16 MB (Table 1) RAM, a 1.05-gigabyte hard drive, and a 32-bit ethernet card for access to our anatomic pathology reporting system. We have designed a push-button workstation for acquiring and indexing images that does not significantly interfere with surgical pathology sign-out. Advantages of the system include the following: (1) Improving patient care: the availability of gross images at time of microscopic sign-out, verification of recurrence of malignancy from archived images, monitoring of bone marrow engraftment and immunosuppressive intervention after bone marrow/solid organ transplantation on repeat biopsies, and ability to seek instantaneous consultation with any pathologist on the network; (2) enhancing the teaching environment: building a digital surgical pathology atlas, improving the availability of images for conference support, and sharing cases across the network; (3) enhancing research: case study compilation, metastudy analysis, and availability of digitized images for quantitative analysis and permanent/reusable image records for archival study; and (4) other practical and economic considerations: storing case requisition images and hand-drawn diagrams deters the spread of gross room contaminants and results in considerable cost savings in photographic media for conferences, improved quality assurance by porting control stains across the network, and a multiplicity of other advantages that enhance image and information management in pathology.

Computer Systems↗
PubMed1994

Computer-assisted instruction in pathology residency training: design and implementation of integrated productivity and education workstations.

Computer-assisted instruction (CAI) has been significantly advanced by the development of inexpensive multimedia personal computers (PCs). As a part of efforts to integrate PC workstations as the primary interface to the anatomic pathology information system, we undertook an evaluation and implementation of image-based resident workstations drawing on technology and software now available. The goal was to develop an integrated diagnostic and research data center using PC workstations. After considerable analysis we implemented a Resident's Resource Center (RRC) to augment the training environment of the resident pathologist by providing productivity tools for the writing, research, and presentation needs of the trainee. We also provided video- and text-based education applications specifically tailored to the training pathologist. This led to the creation of two types of Windows-based workstations. The Productivity Workstation consists of a flatbed scanner, laser printer, and photorecorder connected to a 486-type PC. The Education Workstation consists of a high-resolution monitor and video disc player with bar code scanner connected to a 486-type PC. We briefly review the literature concerning CAI in pathology; outline the hardware, software, personnel and cost concerns that we faced in setting up our RRC; provide a partial list of vendors and programs currently on the market; review the software we have installed; and discuss the results of our efforts.

Computer Systems↗
PubMed1994

E-mail, the Internet, and information access technology in pathology.

In the Age of Information, the Internet has become a fast, powerful, international information resource that has forever transformed the way we view and use information. The need to quickly access, search, and manage information has grown into a challenging task as the amount of information that is available has grown exponentially over the past few years. As people venture onto this growing information superhighway, traveling may be fast and easy for the expert user, but for most, the trip can be intimidating. For the pathologist who faces overwhelming amounts of printed information today, there is an increasing need for tools to manage medical informatics. The Internet has become the toolbox for many to efficiently search, find and manage information. However, just as the information itself steadily becomes more and more abundant and complex, the Internet continues to grow more and more sophisticated. This sophistication oftentimes leads to more confusion and may actually limit its potential to users. In an attempt to demystify the Internet, this article will discuss its basic features and functions with a focus on information resources available to the pathologist such as E-mail, Gopher, and the World Wide Web. Knowledgeable use of the Internet and its vast resources will greatly increase the quality of patient care.

Computer Communication Networks↗
PubMed1993

Comparative analysis of mitogenic and morphogenic effects of HGF and EGF on rat and human hepatocytes maintained in collagen gels.

Hepatocytes maintained in collagen gels remain differentiated for prolonged periods of time compared to cells maintained on conventional cultures. Previous studies with other culture systems in which chemical supplements or substratum modifications enhanced hepatocyte differentiation showed that in all of these systems hepatocytes do not respond to mitogens. In this study it is shown that hepatocytes maintained between two layers of collagen gels respond to mitogens HGF (also known as scatter factor (HGF/SF)) and epidermal growth factor (EGF). Cell density did not affect the responsiveness to mitogens as in conventional cultures. In addition both mitogens (HGF more pronounced) induce characteristic morphogenic changes in which hepatocytes form processes and join in formation of cords. Hepatocytes respond to mitogens for up to 6 days in culture at which point they become refractory to further mitogenic stimulation. This occurs despite electron microscopic evidence that these cells are fully viable when they become refractory to mitogenesis. The refractory state is not modified by substitution of one growth factor for the other or by addition of growth factors at different times. Hepatocytes in the refractory state become again responsive to mitogens when the collagen gels are dispersed by collagenase and the cells are replated on conventional substrates.

Animals↗
PubMed1993

Liver allograft rejection in sensitized recipients. Observations in a clinically relevant small animal model.

A sequential analysis of liver allograft rejection in sensitized rats using immunopathological and ultrastructural microscopy is described. Lewis rats were primed with four ACI skin grafts and challenged with an arterialized ACI orthotopic liver allograft 14 to 17 weeks later. The sensitization resulted in a mix of IgG and IgM lymphocytotoxic antibodies at a titer of 1:512 at the time of transplantation. Specificity analysis of pretransplant immune sera revealed a predominance of IgG anti-class I major histocompatibility complex (RT1) antibodies with a minor IgG fraction showing apparent endothelial cell specificity (non-RT1). This level of sensitization was associated with accelerated graft failure in 3 to 5 days from mixed humoral and cellular rejection. Sequential analysis of serial posttransplant graft biopsies revealed diffuse vascular IgG deposition and platelet thrombi in portal veins and periportal sinusoids within 3 minutes after reperfusion. This was followed by endothelial cell hypertrophy and vacuolization, periportal hepatocyte necrosis, arterial spasm, focal large bile duct necrosis, and hilar mast cell infiltration and degranulation. However, the liver allografts did not fail precipitously and hyperacute rejection was not seen. Kupffer cell phagocytosis of the sinusoidal platelets began as early as 30 minutes posttransplant and by 24 hours, the platelet thrombi had decreased. Cholangioles appeared focally at the edge of the limiting plates by 2 to 3 days, apparently in response to earlier periportal hepatocyte damage. A mononuclear portal and perivenular infiltrate became evident at 3 days, and graft failure was attributed to both antibody and cell-mediated rejection (Furuya et al: Preformed lymphocytotoxic antibodies: Hepatology 1992, 16: 1415-1422). The model described resembles observations in crossmatch positive human liver allograft recipients. The mechanisms of hepatic graft resistance to antibody mediated rejection and the possible long term consequences of early damage to the biliary tree are discussed.

Animals↗
PubMed1992

Experimental autoimmune cystitis: a potential murine model for ulcerative interstitial cystitis.

Interstitial cystitis is an inflammatory disease of unknown etiology. To facilitate the study of the pathophysiology of interstitial cystitis, an animal model that correlates with the clinical features of interstitial cystitis and expresses histologic features consistent with those observed in interstitial cystitis patients was developed. Various strains of mice were immunized with a syngeneic bladder homogenate to determine their susceptibility to the induction of autoimmune cystitis. Of 3 mouse strains tested, only the Balb/cAN mice reproducibly developed the clinical correlates and histological features consistent with those observed in interstitial cystitis. In a blinded pathologic review, autoreactive Balb/cAN bladders were correctly distinguished from chronic bacterial cystitis, sham treated bladders and normal control bladders. Edema, fibrosis, perivascular lymphocytic infiltrations and detrusor mast cell accumulation were apparent in 75% of the Balb/cAN mice 2 weeks after immunization and 100% at 4 weeks. These histologic features plateaued and remained stable for at least 6 months. Grossly, the immunized mouse bladders were fibrotic and contracted with a significantly (p < .05) decreased fluid capacity. On hydrodistension, increased vascular prominence and petechial hemorrhage (glomerulations) were evident. Instillation of 14C-urea demonstrated increased permeability in immunized bladders compared with controls. A cellular autoimmune basis for the cystitis is supported by adoptive transfer studies. Spleen cells from experimental mice but not controls transferred the histological features of the disease to naive mice. These studies outline the development of a new experimental autoimmune cystitis model that expresses features similar to those frequently observed in human interstitial cystitis, and may provide a model for the study of the inflammatory process associated with interstitial cystitis. Furthermore, these data suggest a possible role for cellular immune components in interstitial cystitis.

Animals↗
PubMed1992

The relative proportion of stromal and epithelial hyperplasia is related to the development of symptomatic benign prostate hyperplasia.

The specific features of the prostate adenoma predisposing to the development of symptomatic benign prostatic hyperplasia (BPH) are unknown. Our objective was to determine whether the histological composition of the prostate adenoma is related to the development of symptomatic BPH. Prostate adenomas were obtained from men with asymptomatic BPH undergoing cystoprostatectomy for invasive transitional cell carcinoma, and from men with symptomatic BPH undergoing open prostatectomy, transurethral resection of the prostate and pharmacotherapy. The severity of bladder outlet obstruction was evaluated with the Boyarsky symptom score and uroflowmetry. The percentages of stroma, epithelium and glandular lumen were determined in the prostate adenomas via quantitative image analysis on a computer-assisted morphometry system. The prostate adenomas from the 33 men with symptomatic BPH contained 62 +/- 1%, 15 +/- 1% and 23 +/- 1 of stroma, epithelium and glandular lumen, respectively. The prostate adenomas from 6 men with asymptomatic disease contained 54 +/- 1%, 21 +/- 1% and 25 +/- 1% of stroma, epithelium and glandular lumen, respectively. The ratios of stromal-to-epithelial hyperplasia in the prostate adenomas from men with symptomatic and asymptomatic disease were 4.6 +/- 0.3 and 2.7 +/- 0.1, respectively. The differences in percentage of stroma and epithelium, and the stromal-to-epithelial ratio in the prostate adenomas from men with symptomatic and asymptomatic BPH were statistically significant. Our study suggests that the histological composition of the prostate adenoma is related to the development of symptomatic BPH.

Aged↗
PubMed1992

Arrested maturation of cerebral neurons, axons and myelin: a new familial syndrome of newborns.

A new lethal familial syndrome of unknown etiology is described in two male siblings who died in the newborn period. Both had corneal edema and were hypotonic, requiring assisted ventilation at birth. Neuropathological findings included an immature appearance of neocortical neurons, with cortical architecture similar to that normally seen in an infant of 5 months gestational age. Axons and myelin were absent in the cerebral and cerebellar white matter, and also in descending white matter tracts of brainstem and spinal cord. Subacute inflammation was seen in the anterior horns of the spinal cord in both cases, although there was no evidence of inflammation elsewhere in the nervous system. Electron microscopy of endothelial cells from brain, spinal cord and a number of other tissues of the second sibling showed tubuloreticular inclusions (TRIs). There are no known previous reports of similar neuropathology. Future recognition of this condition will be important for genetic counselling.

Abnormalities, Multiple↗
PubMed1992

Caco-2 cell transfection by rat intestinal alkaline phosphatase cDNA increases surfactant-like particles.

The rat enterocyte produces a particle with surfactant-like properties (including a whorled appearance, enrichment for dipalmitoyl phosphatidylcholine, and ability to lower surface tension) that also is enriched for intestinal alkaline phosphatase. Human Caco-2 cells grown on polycarbonate filters were utilized to study the secretion of these particles and exhibited whorls and strands of unilamellar membranes, particularly concentrated at the apical pole or near junctional complexes. Concentrated culture medium from these cells separated on continuous NaBr gradients revealed a fraction at density = 1.07 g/l enriched for phosphatidylcholine and intestinal alkaline phosphatase. This fraction contained membranous sheets containing alkaline phosphatase, detected by immunolocalization. Phosphatidylcholine comprised 54% of phospholipid in this fraction, compared with 20% in brush borders. When Caco-2 cells were transfected with cDNA encoding rat intestinal alkaline phosphatase, cellular phosphatase activity increased twofold, but activity in the medium increased 14-fold to > 200 (average 32)-fold. Ultrastructurally, compared with mock-transfected cells or cells transfected with human placental alkaline phosphatase, transfection with rat intestinal alkaline phosphatase cDNA led to intracellular and extracellular accumulation of surfactant-like particles. We conclude that surfactant-like particles are produced by Caco-2 cells, and their production can be enhanced by transfection with a cDNA encoding a protein known to be associated with such particles.

Alkaline Phosphatase↗
PubMed1992

'Diaphragmlike' stricture and ulcer of the colon during diclofenac treatment.

Diclofenac sodium is a widely used enteric-coated nonsteroidal anti-inflammatory drug. We describe a woman with Hemoccult-positive stools and iron deficiency anemia who developed both a colonic ulcer and a "diaphragm-like" colonic stricture while taking enteric-coated diclofenac. These lesions were evident on colonoscopy but not on barium studies. Biopsy specimens of the ulcer and stricture revealed particulate matter that was indistinguishable from diclofenac pill fragments by electron microscopy. Discontinuation of diclofenac therapy resulted in resolution of anemia and Hemoccult-positive stools. We conclude that (1) enteric-coated diclofenac is associated with both colonic ulcers and diaphragm-like colonic strictures; (2) the pathophysiologic mechanism for the development of both ulcers and strictures may involve a direct action of diclofenac within these lesions; (3) colonoscopy may be superior to barium studies in evaluating patients receiving diclofenac who have iron deficiency anemia and/or Hemoccult-positive stools.

Anemia, Hypochromic↗
PubMed1992

Intracortical small cell osteosarcoma.

A case of intracortical osteosarcoma, a rare form of osteosarcoma that may radiologically simulate a variety of benign and malignant bone lesions, is described. To date, all cases have arisen in the diaphysis of either the tibia or femur, and histologically have been of osteoblastic type. In contrast, the current tumor was a small cell osteosarcoma, another uncommon variety of osteosarcoma. A summary of the reported cases of intracortical osteosarcoma is given, and the literature on small cell osteosarcoma is briefly reviewed.

Adolescent↗
PubMed1991

Bladder wall abnormalities in myelodysplastic bladders: a computer assisted morphometric analysis.

Myelodysplasia represents the most common cause of neurogenic bladder dysfunction in children. The specific histological features associated with myelodysplastic bladders have not been previously characterized. Our objective was to study the relationship between smooth muscle and connective tissue in control and myelodysplastic bladders using classical morphometric analysis with the assistance of an automated image analysis system. Gross histological analysis of the bladder specimens of normal stillborn fetuses showed organized muscle bundles embedded in a small amount of connective tissue. The bladder specimens of myelomeningocele stillborn fetuses showed a marked paucity of muscle bundles as well as a significantly diminished size of the muscle bundles. The myelomeningocele bladder specimens obtained from patients undergoing autopsy and those undergoing augmentation cystoplasty revealed significant interfascicular and pericellular infiltration of the smooth muscle by dense connective tissue. Quantitative morphometric analysis showed that the myelomeningocele stillborn fetuses have a significant increase in the volumetric content of connective tissue compared to control stillborn fetuses. The bladders of myelomeningocele patients who underwent autopsy or augmentation cystoplasty had a 3-fold increase in connective tissue when compared to normal controls. These findings reveal that structural changes in the histological components of the myelodysplastic bladder can be demonstrated not only in patients of varying ages undergoing autopsy or augmentation cystoplasty but also in the developing fetus. These findings enhance our understanding of the relationship of connective tissue proliferation to smooth muscle in the myelodysplastic bladder. We discuss the relationship of these findings to pathological detrusor morphology and detrusor dysfunction.

Child↗
PubMed1991

Internalization of bacille Calmette-Guerin by bladder tumor cells.

Mechanisms by which intravesical bacille Calmette-Guerin (BCG) treatment mediates antitumor activity are currently poorly understood. We have determined that both human bladder tumor (T-24) and mouse bladder tumor (MBT-2) cells are capable of internalizing the BCG and have characterized this process in vitro. The internalization of BCG by T-24 and MBT-2 cells was verified by histochemistry and electron microscopy. Time dependent internalization of BCG was observed with a maximum occurring at three hrs. Internalization was significantly inhibited by both incubation at 4C and cytochalasin B; conditions known to inhibit phagocytosis. Ultrastructural studies suggested that BCG were transported to membrane bound intracellular compartments and were degraded. The compartments containing the degraded mycobacteria labeled with the fluid phase marker HRP which is known to be transported to lysosomes in a variety of cell types. To determine if the internalization process occurred in vivo, we examined bladder washings of patients treated with intravesical BCG. The majority of the cells in the bladder washings were inflammatory cells which contained ingested BCG. In addition, internalized and degraded BCG were identified in urothelial cells. These data demonstrate that BCG are internalized by transitional epithelial cells both in vitro and in vivo. The internalization process is inhibitable by temperature and microfilament disruption. The potential therapeutic implications of this process and its relationship to antitumor activity of BCG therapy are currently being investigated.

Actin Cytoskeleton↗
PubMed1991

Developmental expression of intestinal surfactant-like particles in rats.

We have reported the appearance of surfactant-like particles enriched for intestinal alkaline phosphatase and phosphatidylcholine within enterocytes and in the lumen of adult fat-fed rat intestine. Because rat pulmonary surfactant decreases in abundance during the first postnatal days, we examined the developmental expression of these intestinal particles in suckling rats. Electron microscopy revealed abundant particles in 1-day-old rats within and surrounding the villus enterocytes, declining in frequency by day 14. Phosphatidylcholine content, alkaline phosphatase, sucrase-isomaltase, and lactase activity in particles peaked 1 day after birth, declining rapidly to adult levels by day 3 of life, except for sucrase, which peaked again after weaning. The postnatal developmental profile of the same brush-border-associated enzymes was totally different. Membrane fractions enriched for alkaline phosphatase and of similar density to rat surfactant-like particles were isolated from the small intestine of an amphibian (Xenopus laevis) and a fish (grass carp). Electron microscopy of the Xenopus membranes revealed unilamellar structures similar to the rat particles, but the carp membranes were of dissimilar morphology. We conclude that particles with surfactant-like properties in the rat intestine are ontogenically expressed like pulmonary surfactant; similar particles are evident only in animals with lungs.

Alkaline Phosphatase↗