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M Tammi

Publications and source records attributed to M Tammi.

At least 19 recordsLinked to original sources
PubMed1998

Tumor cell-associated hyaluronan as an unfavorable prognostic factor in colorectal cancer.

Hyaluronan (HA) is a linear high molecular weight extracellular polysaccharide. It is thought to be involved in mitosis and the enhancement of wound healing, tumor invasion, and metastasis. Because its clinical relevance in cancer has not been explored, we scored HA in colorectal adenocarcinoma and studied its relationship with patient survival. A specific probe prepared from cartilage proteoglycan aggregates was used to stain paraffin-embedded tumor samples from 202 colorectal adenocarcinoma patients treated in Kuopio University Hospital and followed up for a mean of 14 years. The hypothesis that the percentage of HA-positive carcinoma cells (HA%) and HA intensity in cancer cells correlated with survival was tested with the log-rank test, hazard ratios, and their confidence intervals. Ninety-three % of tumors had at least a proportion of carcinoma cells positive for HA. HA intensity in tumor epithelium was stronger in Dukes' stages C and D tumors and in high-grade tumors. The cancer-related survival rate was lower among patients with strong HA intensity in tumor epithelium (P < 0.001) and high HA% (P < 0.001). Recurrence-free survival was also shorter in patients with an intense signal for HA (P = 0.001) and high HA% in tumor epithelium (P = 0.04). HA intensity in tumor epithelium independently predicted survival and recurrence-free survival (Cox's analysis). We conclude that a high proportion of HA-positive cancer cells and high intensity of the HA-signal predicts a poor survival rate. The abnormal expression of HA in the neoplastic colon epithelial cells is suggested to provide a distinct advantage for invasive growth and metastasis.

Adenocarcinoma↗
PubMed1998

Hyaluronan in the interphotoreceptor matrix of the eye: species differences in content, distribution, ligand binding and degradation.

Hyaluronan (HA) distribution in the posterior eye wall from the vitreous through the sclera, with special consideration to localization in the retina and interphotoreceptor matrix (IPM), was evaluated in human, bovine, guinea pig, dog, rat and mouse tissues using a specific probe for HA (bHABC, biotinylated hyaluronan binding complex). The sclera, some regions of the choroid and vitreous body was positive for HA, as was the basal lamina of the retina (inner limiting membrane). bHABC binding was detected in the IPM of all species studied except the mouse. Predigestion with Streptomyces hyaluronidase for 3 hr before bHABC application eliminated binding in the vitreous, choroid, sclera and basal lamina of the retina, but did not eliminate bHABC binding in the IPM. In tissues from all species studied, incubation for 6 hr with hyaluronidase eliminated bHABC binding in the IPM, except for two human samples. In these two human samples, HA specific binding in the IPM persisted even after 24 hr enzyme treatment. bHABC failed to bind to any tissue layer when bHABC was preincubated with hyaluronan oligosaccharides before application. The resistance of the IPM HA to hyaluronidase digestion may reflect extensive coverage of HA binding sites by ligands present in this compartment which hinder enzyme access. The absence of bHABC binding to the IPM when the probe is preincubated with HA oligosaccharides indicates that the binding reflects specific interaction with HA. We conclude that, with the exception of the mouse, HA is a prominent constituent of the IPM, where it may serve to organize the matrix by functioning as a basic scaffold to which other macromolecules in the insoluble IPM are attached.

Adolescent↗
PubMed1998

Ultrastructural analysis of human epidermal CD44 reveals preferential distribution on plasma membrane domains facing the hyaluronan-rich matrix pouches.

We used immunogold staining and stereology to examine the ultrastructural localization and to estimate the relative content of CD44 in different strata and cell types of normal human epidermis. We found that CD44 existed almost exclusively on the plasma membranes; only rare labeling occurred on vesicular structures within the cytoplasm. Quantitation of the immunogold particles indicated that the labeling density of melanocytes corresponded to that of basal keratinocytes, and Langerhans cells displayed a labeling density of approximately 10% that of the surrounding spinous cells. Among keratinocyte strata, the highest labeling density occurred on spinous cells, suggesting upregulation of CD44 after detachment from the basement membrane. The plasma membrane distribution of CD44 was compartmentalized, with little signal on cell-cell and cell-substratum contact sites such as desmosomes, the plasma membrane domain facing the basement membrane, and the close apposition of terminally differentiating granular cells. In contrast, CD44 was abundant on plasma membrane domains facing an open intercellular space, rich in hyaluronan. This distribution is in line with a role of CD44 as a hyaluronan receptor, important in the maintenance of the intercellular space for nutritional and cell motility functions in stratified epithelia.

Biotinylation↗
PubMed1997

Polyamine-dependent alterations in the structure of microfilaments, Golgi apparatus, endoplasmic reticulum, and proteoglycan synthesis in BHK cells.

The activity of ornithine decarboxylase, the key enzyme in the synthesis of polyamines, is essential for proliferation and differentiation of all living cells. Two inhibitors of ornithine decarboxylase, alpha-difluoromethylornithine (DFMO) and 1-aminooxy-3-aminopropane (APA), caused swelling of endoplasmic reticulum (ER) and medial and trans Golgi cisternae, and the disappearance of stress fibers, as visualized by staining with fluorescent concanavalin A (ConA), C6-NBD-ceramide or wheat germ agglutinin (WGA), and phalloidin, respectively. In contrast, the pattern of microtubules, stained with a beta-tubulin antibody, was not affected. Rough ER seemed to be especially affected in polyamine deprivation forming whorls and involutions, which were observed by transmission electron microscopy. Since ER and Golgi apparatus are vital parts of the glycosylation and secretory machinery of the cell, we tested the ability of these structurally altered cell organelles to synthesize proteoglycans using [3H]glucosamine and [35S]sulfate as precursors. The total incorporation rate into proteoglycans and hyaluronan was not reduced in polyamine-deprived cells, suggesting that the total glycosylation capacity of cells was not affected. However, the synthesis of a high molecular weight proteoglycan containing chondroitin and keratan sulfate was completely inhibited. The remodeling of cytoskeleton and rough endoplasmic reticulum in polyamine deprivation may perturb the synthesis and secretion of the components of membrane skeleton and of the extracellular matrix, e.g., proteoglycans. Rough ER and cytoskeleton may be the targets where polyamines affect cell proliferation and differentiation.

Actin Cytoskeleton↗
PubMed1997

CD44 substituted with heparan sulfate and endo-beta-galactosidase-sensitive oligosaccharides: a major proteoglycan in adult human epidermis.

CD44 is a group of cell surface glycoproteins that is generated from a single gene by mRNA splice variation. Its functions in matrix adhesion and tumor invasion are strongly influenced by glycosylation. We studied the glycosylated tissue forms of CD44 from extracts of normal adult human epidermis by using western blotting and immunoprecipitation from short-term skin organ cultures. An antibody for CD44 (Hermes 3) precipitated 7-17% of all 35SO4-labeled proteoglycans (PGs) synthesized in epidermis. Immunoprecipitates digested with heparitinase lost 40-68% of incorporated 35SO4 and 24-40% of [3H]glucosamine, indicating that heparan sulfate was the predominant glycosaminoglycan in epidermal CD44. Chondroitinase ABC released 10-25% and 6-12% of 35SO4 and [3H]glucosamine, respectively. Less than 5% of both isotopes were susceptible to keratanase. Five to 33% of 35SO4 and 26-37% of [3H]glucosamine, however, was released by endo-beta-galactosidase, implying marked substitution by oligosaccharides with N-acetyllactosamine repeats. Heparitinase pretreatment retarded, whereas endo-beta-galactosidase enhanced the mobility of the > or = 180-kDa polydisperse CD44 on agarose gel electrophoresis. On SDS-polyacrylamide gel electrophoresis, however, western blotting and fluorographs of 35SO4-labeled immunoprecipitates showed the main CD44 isoform at > or = 250 kDa and a shift to 180-200 kDa after heparitinase treatment. Keratanase, keratanase II, and chondroitinase ABC had minor effects. A less abundant form of CD44, with a core of 100 kDa, partly substituted with chondroitinase ABC- and endo-beta-galactosidase-sensitive chains, was also present. Therefore, the large heparan sulfate-substituted CD44 forms a significant part of all proteoglycans in normal human epidermis. Both the large and the 100-kDa variant of epidermal CD44 contain endo-beta-galactosidase-sensitive oligosaccharides not previously noted in other cells or tissues.

Adult↗
PubMed1997

Developmentally programmed expression of hyaluronan in human skin and its appendages.

The expression of hyaluronan (HA) in fetal human skin was studied by using a biotinylated HA-binding probe. The uniform expression of HA in primitive skin was changed after the 9th week, when differentiation of the basement membrane zone increased HA in the subepidermal mesenchyme. Maturation of the papillary dermis at the 12-20th weeks led to the thickening of this HA-enriched zone; the underlying reticular layer was less intensely stained. In epidermis the number of cell layers rapidly increased after the 9th week. At first all epidermal layers were HA-positive. A complete loss of HA from the upper intermediate cells on the 18th week preceded the formation of mature granular and cornified layers. Peridermal cells remained HA-positive even when the underlying stratum corneum turned negative. The tightly apposed basal epithelial cells, the first stage of hair follicle and eccrine sweat gland formation, became almost completely depleted of HA. With advancing bulb development HA returned in the epithelial compartment, until maturation of the hair follicles restricted its expression to the outer root sheath and hair matrix. Maturation of the sebaceous glands led to the expression of HA pericellularly in the germinative cells and intracellularly in the mature sebocytes. Marked changes thus occur in the distribution of HA during fetal skin development; the primitive tissues exhibited a uniform widespread expression of HA, and maturing tissues showed distinct locally regulated patterns. The loss of epithelial HA in the hair follicle anlagen and upper intermediate cells turned out to be early differentiation markers.

Cell Differentiation↗
PubMed1996

Spatial distribution of CD44 and hyaluronan in the proximal tibia of the growing rat.

CD44 has been described as a cell surface hyaluronan receptor present on a variety of different cells, and it is generally assumed to be prevalent in most connective tissues that contain hyaluronan. A major aim of this study was to test that presumption by localizing CD44 and hyaluronan within several tissues of the proximal tibia of the growing rat. Comparison of these profiles would reveal whether CD44 and hyaluronan co-localize with high fidelity, as would be expected if CD44 were a major hyaluronan binding protein. Using in situ hybridization and immunohistochemistry, CD44 was identified on osteoclasts, chondroclasts, osteocytes, hematopoietic marrow cells, synovial cells, and connective tissue fibroblasts (ligaments, tendons, and fascia). Although the majority of osteocytes expressed CD44, reduced expression was observed for osteoblasts and ostcoprogenitor cells. Additionally. CD44 was not detected on chondrocytes from epiphyseal and metaphyseal growth cartilages or in meniscal fibrocartilage. Using biotinylated G1 domain from aggrecan and link protein, hyaluronan was observed in the maturational and hypertrophic zones of all growth cartilages, the synovium and other fibroblastic connective tissues, regional areas of the periosteum and endosteum (around osteoblasts, osteoprogenitor cells, and osteoclasts), osteocyte lacunae, and surrounding blood vessels. In regions of co-localization for CD44 and hyaluronan, it seems that CD44 is a likely hyaluronan binding protein in several tissues of the proximal tibia. However, it does not appear to be the predominant hyaluronan binding protein in growing cartilages of the weanling rat.

Aggrecans↗
PubMed1996

Safranin O reduces loss of glycosaminoglycans from bovine articular cartilage during histological specimen preparation.

The ability of Safranin O, added to fixation and decalcification solutions, to prevent the escape of glycosaminoglycans (GAGs) from small cartilage tissue blocks during histological processing of cartilage has been studied. GAGs in the fixatives and decalcifying solutions used and those remaining in the 1 mm3 cubes of cartilage were assayed biochemically. The quantity of GAGs remaining in the cartilage cubes were determined from Safranin O-stained sections using videomicroscopy or microspectrophotometry. A quantity (10.6%) of GAGs were lost during a conventional 4% buffered formaldehyde fixation (48 h) and a subsequent decalcification in 10% EDTA (12 days) at 4 degrees C. Roughly one-quarter of the total GAG loss occurred during the 48 h fixation, and three-quarters during the 12 days of decalcification. Inclusion of 4% formaldehyde in the decalcification fluid decreased the loss of GAGs to 6.2%. The presence of 0.5% Safranin O in the fixative reduced this loss to 3.4%. When 0.5% Safranin O was included in the fixative and 4% formaldehyde in the decalcification solution, Safranin O staining of the histological sections increased on average by 13.5%. After fixation in the presence of 0.5% Safranin O, there was no difference in the staining intensities when decalcification was carried out in the presence of either Safranin O or formaldehyde, or both. It took 24 h for Safranin O to penetrate into the deep zone of articular cartilage, warranting a fixation period of at least this long. In conclusion, the addition of Safranin O to the fixative and either Safranin O or formaldehyde in the following decalcification fluid, markedly reduces the loss of GAGs from small articular cartilage explants during histological processing. However, for immunohistochemical studies, Safranin O cannot be included in the processing solutions, because it may interfere.

Animals↗
PubMed1996

Hyaluronan distribution in the normal epithelium of esophagus, stomach, and colon and their cancers.

The distribution of hyaluronan (HA) in normal gastrointestinal wall and in tumors originating from their epithelium was studied using a specific probe prepared from cartilage proteoglycan (bHABC, biotinylated hyaluronan binding complex). The normal stratified squamous epithelium of esophagus showed an intense HA staining in the basal and lower intermediate layers, whereas the simple epithelia in the stomach and large intestine were HA negative. Esophageal in situ carcinomas expressed HA also in the cell layers close to the luminal surface, in regions normally negative. Most of the invasive squamous cell carcinomas maintained their HA expression, but in very poorly differentiated types the tumor parenchyma was devoid of HA. In both gastric and colonic adenocarcinomas the tumor parenchyma showed no HA. The stromal tissue was intensely HA positive in all tumors. Cancer cells invading the intestinal smooth muscle were surrounded by copious amounts of HA, whereas the muscular layer was otherwise very poor in HA staining. These results show that relatively well differentiated carcinoma cells themselves retain the high or low HA expression pattern of their original epithelium, whereas tumors stimulate HA deposition in the surrounding stroma.

Colon↗
PubMed1995

Hydrocortisone regulation of hyaluronan metabolism in human skin organ culture.

We studied the influence of hydrocortisone (HC) on hyaluronan (HA) metabolism in explants of human skin, a model retaining normal three-dimensional architecture of dermal connective tissue and dynamic growth and stratification of epidermal keratinocytes. The synthesis of hyaluronan and proteoglycans (PGs), and DNA, were determined with 3H-glucosamine and 3H-thymidine labelings, respectively. The total content and histological distribution of hyaluronan was studied utilizing a biotinylated aggrecan-link protein complex. A low concentration of HC (10(-9) M) stimulated the incorporation of 3H-glucosamine into hyaluronan in epidermis by 23% and reduced the disappearance rate of hyaluronan by 25% in chase experiments, resulting in a 74% increase in total hyaluronan (per epidermal dry weight) after a 5-day culture in 10(-9) M HC. On the other hand, a high concentration of HC (10(-5) M) reduced both synthesis (-42%) and degradation (-46%) of epidermal hyaluronan during 24 h labeling and chase periods. The cumulative effect of a 5-day treatment was a 24% decrease of total epidermal hyaluronan. The high dose (10(-5) M) also reduced keratinocyte DNA synthesis and epidermal thickness. In dermis, only the high (10(-5) M) concentration of HC was effective, inhibiting the incorporation of 3H-glucosamine into hyaluronan by 28%. No significant influences on total hyaluronan content or the disappearance rate of hyaluronan in dermal tissue was found. All HC concentrations lacked significant effects on newly synthesized PGs in epidermal and dermal tissues, but reduced the labeled PGs diffusing into culture medium. A low physiological concentration of HC thus maintains active synthesis and high concentration of hyaluronan in epidermal tissue, while high pharmacological doses of HC slows hyaluronan turnover and reduces its content in epidermis, an effect correlated with enhanced terminal differentiation, reduced proliferation rate and reduced number of vital keratinocyte layers.

Cell Division↗
PubMed1995

Influence of short-term hydrostatic pressure on organization of stress fibers in cultured chondrocytes.

The present study describes changes in the organization of stress fibers that occur in articular cartilage chondrocytes subjected to hydrostatic pressure. Primary cultures of chondrocytes from bovine articular cartilage, grown on coverslips, were subjected to 5, 15, or 30 MPa hydrostatic pressure at 37 degrees C. The pressure was applied continuously or cyclically at two frequencies: 0.125 Hz (4 seconds of pressure and 4 seconds of no pressure) or 0.05 Hz (1 second of pressure and 19 seconds of no pressure) for a period of 2 hours. Control chondrocytes showed a polygonal form with prominent stress fibers extending across the cells. The exposure of cells to 30 MPa pressure caused a nearly total disappearance of stress fibers and retraction of the cells from each other. With pressure at 15 MPa or cyclic pressure, the number of cells with stress fibers was decreased. In cells subjected to 5 MPa pressure, the stress fibers resembled those in control chondrocytes. The pressure effects were reversible after 2 hours. Pressure had no effect on the staining pattern of vinculin, which suggests that microfilaments are more vulnerable to pressure than vinculin. The results indicate that cytoskeletal changes may be an integral part of the response of chondrocytes to hydrostatic pressure.

Animals↗
PubMed1995

Long-distance running alters bone anthropometry, elemental composition and mineral density of young dogs.

Ten young beagle dogs were run on a treadmill for 1 year, the last 15 weeks 40 km/day. Thereafter bone anthropometric variables, elemental composition, mineral density (BMD) and serum markers of bone metabolism were analyzed and compared with matched-paired control dogs. More osteophytes developed, weight-bearing bones grew larger and BMD of axial skeleton was reduced in the trained group. Zinc and sodium accumulated in bones of the runners. Zinc correlated negatively with BMD. Serum osteocalcin and C-terminal propeptide of type I procollagen did not correlate with the observed differences in BMD. This experiment implies that intensive endurance training in adolescence may reduce the peak bone mass and alter the structural properties of bone.

Animals↗
PubMed1995

Proteoglycan depletion and size reduction in lesions of early grade chondromalacia of the patella.

OBJECTIVE: To determine the content and molecular size of proteoglycans (PGs) in patellar chondromalacia (CM) and control cartilages as a first step in investigating the role of matrix alterations in the pathogenesis of this disease. METHODS: Chondromalacia tissue from 10 patients was removed with a surgical knife. Using identical techniques, apparently healthy cartilage of the same site was obtained from 10 age matched cadavers (mean age 31 years in both groups). Additional pathological cartilage was collected from 67 patients with grades II-IV CM (classified according to Outerbridge) using a motorised shaver under arthroscopic control. The shaved cartilage chips were collected with a dense net from the irrigation fluid of the shaver. The content of tissue PGs was determined by Safranin O precipitation or uronic acid content, and the molecular size by mobility on agarose gel electrophoresis. RESULTS: The mean PG content of the CM tissue samples with a knife was dramatically reduced, being only 15% of that in controls. The cartilage chips collected from shaving operations of grades II, III, and IV CM showed a decreasing PG content: 9%, 5%, and 1% of controls, respectively. Electrophoretic analysis of PGs extracted with guanidium chloride from the shaved tissue samples suggested a significantly reduced size of aggrecans in the mild (grade II) lesions. CONCLUSION: These data show that there is already a dramatic and progressive depletion of PGs in CM grade II lesions. This explains the softening of cartilage, a typical finding in the arthroscopic examination of CM. The PG size reduction observed in grade II implicates proteolytic attack as a factor in the pathogenesis of CM.

Adult↗
PubMed1994

Articular cartilage thickness and glycosaminoglycan distribution in the young canine knee joint after remobilization of the immobilized limb.

The recovery of articular cartilage from atrophy induced by joint immobilization was investigated in immature dogs. In a previous study, we showed that 11 weeks of immobilization of the knee (stifle) joint of young dogs reduced the concentration of articular cartilage glycosaminoglycans (GAGs) by 13-47%. In the present study, right hindlimbs from six female beagles were immobilized for 11 weeks, as in the previous study, and then were remobilized for 15 weeks. Cartilage from the knee joint was compared with cartilage from nonimmobilized knees of eight age-matched control beagles. Histological samples taken from 11 different locations of the knee joint were stained with safranin O, and microspectrophotometry was used to demonstrate distribution of GAGs in the tissue. After remobilization, GAG concentration was restored in the patellofemoral region and tibial condyles. On the summits of the femoral condyles, and especially at the periphery of the femoral condyles, GAG concentration remained 8-26% less than the control values. On the summits, the thickness of the uncalcified cartilage was as much as 15% less than in the age-matched controls. Consequently, the changes induced by unloading were reversible to a great extent, but a full restoration of articular cartilage was not obtained at all sites of the knee joint within the 15 weeks of remobilization. Immobilization of the skeletally immature joint therefore may affect the development of articular cartilage in such a way that very slow recovery or permanent alterations are induced.

Animals↗
PubMed1994

A dot-blot assay of metabolically radiolabeled hyaluronan.

Glycosaminoglycans labeled in tissue culture in the presence of [3H]glucosamine were proteolytically solubilized and then precipitated with cetylpyridinium chloride onto a sheet of nitrocellulose using a dot-blot apparatus. The proportion of hyaluronan (HA) was calculated from parallel aliquots digested with Streptomyces hyaluronidase, an enzyme specifically degrading HA. A linear response of radioactivity was obtained for samples in the range of 50-10,000 cpm (1-1000 ng total HA) when the dots cut from the membrane were counted with liquid scintillation. Negligible interference from an excess of unincorporated precursor, chondroitin sulfate, and proteolytic tissue digest was observed. The assay was particularly convenient in measuring large numbers of samples with relatively low activity, such as testing the effects of different drug concentrations and analyzing chromatographic fractions.

Cetylpyridinium↗
PubMed1994

Hyaluronan and CD44 in psoriatic skin. Intense staining for hyaluronan on dermal capillary loops and reduced expression of CD44 and hyaluronan in keratinocyte-leukocyte interfaces.

The distributions of hyaluronan (HA) and its presumptive receptor, CD44, were studied in skin samples from 13 psoriasis vulgaris patients, using an HA-specific probe (HABC), and monoclonal antibodies, respectively. The general distribution of HA and CD44 in psoriatic lesional epidermis resembled that in normal epidermis. However, areas of epidermis invaded by leukocytes showed a local depletion of HA and CD44, particularly at the contact areas of keratinocytes to lymphocytes and neutrophils. Removal by cellular uptake or extracellular degradation of CD44 and HA may be required for tight adherence between a keratinocyte and a leukocyte. On the dermal side, the tips of the prolonged dermal papillae in psoriatic lesions were intensively stained with HABC. The dilated capillaries and the space below the tip basal lamina, in particular, were heavily covered with HA. Occasionally, a similar intense staining was seen around an enlarged capillary in uninvolved psoriatic skin. CD44-positive leukocytes were found around the affected capillaries. The accumulation of HA in the dermal papillae may support the growth of psoriatic lesions, since HA stimulates the growth of capillaries as well as attracting inflammatory cells.

Adult↗