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Biomedical subjects

M Tammi

Publications and source records attributed to M Tammi.

At least 73 records · Page 4Linked to original sources
PubMed1994

Proteoglycans in the intervertebral disc of young dogs following strenuous running exercise.

The proteoglycans (PGs) of intervertebral disc were studied in ten beagles which ran on a treadmill for one year (up to 40 km/day) and in ten non-running control dogs. Nucleus pulposus and annulus fibrosus from cervical (C5) and thoracic (T6 and T12) discs were labeled in vitro with 35SO4. The extractability, concentration and synthesis of PGs, and the electrophoretic subpopulations, aggregation and glycosaminoglycan chain lengths of newly-synthesized and total PGs were measured. Sulfate incorporation was significantly elevated by running in the C5 disc and reduced in the annulus of T6 discs. In the annulus of the T6 discs the concentration of total PGs was significantly lower although that of dermatan sulfate PGs was actually higher than in the controls. The results show that enhanced loading of the spine exerts significant alterations in the intervertebral disc PGs in a spine-level specific manner. In the most strained area of the spine (upper thoracic), the alterations in the runners suggest compromised biomechanical properties of the disc.

Animals↗
PubMed1994

Proteoglycan chemistry in experimentally injured porcine intervertebral disk.

An animal model of disk degeneration was used to study the concentration levels and types of proteoglycans in the different parts of the intervertebral disk. An annular incision was made with a scalpel blade into the anterior part of the porcine lumbar intervertebral disks via a retroperitoneal approach. Three months after injury the morphology of the injured disk had changed considerably. Disk height was diminished, and in the injured segment osteophytes had formed at the ventral edges of the vertebral body. The nucleus was small, fibrous, and yellowish. The annular lesion had healed by formation of granulation tissue, but the lamellar structure was partially destroyed. The concentration of inorganic [35S]sulfate had decreased across the whole disk, reflecting a decrease in the rate of solute transport. The concentration of incorporated [35S]sulfate had also decreased in the injured disks. The DNA concentration in the anterior annulus and in the nucleus had increased, whereas both the concentration of uronic acid and the ratio of chondroitin-6-sulfate to chondroitin-4-sulfate in the nucleus had decreased. Agarose gel electrophoresis combined with chondroitinase B digestion suggested the presence of dermatan sulfate proteoglycans in the injured annulus fibrosus. The morphology and chemical composition of the disks adjacent to the injured one were normal, and only a slight increase in the concentration of incorporated [35S]sulfate was observed in the disks above the injured one.

Animals↗
PubMed1993

Long-distance running causes site-dependent decrease of cartilage glycosaminoglycan content in the knee joints of beagle dogs.

OBJECTIVE: To study the effects of a long-term (1-year) program of running exercise (up to 40 km/day) on the thickness and glycosaminoglycan (GAG) content of articular cartilage in the knee and humeral head cartilage of young dogs. METHODS: Samples for histologic analysis were obtained from 12 different locations of the joints. We conducted a detailed, area-specific analysis, measuring the thickness of articular cartilage and analyzing the distribution of Safranin O stain that binds stoichiometrically to GAG as determined by quantitative microspectrophotometry. RESULTS: Running exercise decreased the GAG content of the uncalcified articular cartilage in the weight-bearing summits of the femoral condyles by 5-13% (P < 0.05), while at margins of these areas the GAG content was equivalent to control levels. In the lateral condyle of the femur, the reduction was most prominent in the superficial zone (up to 28% decrease; P < 0.05), and extended into the intermediate zone (11% decrease; P < 0.05). GAG content was also significantly reduced in the superficial zone at the lateral condyle of the tibia and the head of the humerus, by 35% (P < 0.01) and 15% (P < 0.05), respectively. Running did not alter GAG concentration in the patellofemoral region. CONCLUSION: The GAG depletion caused by 40-km/day running exercise is restricted to prominent weight-bearing areas of the joint and begins from the superficial cartilage without signs of degeneration. The different degree and type of joint loading can explain the site-dependent cartilage response to long-distance running. The loss of GAGs was possibly due to breakdown of proteoglycans, which could not be compensated for by neosynthesis of molecules. With time, this may affect the condition of articular cartilage, especially if the joint is exposed to loading for lengthy periods.

Animals↗
PubMed1993

Proteoglycan synthesis in canine intervertebral discs after long-distance running training.

The alterations and distribution of proteoglycan (PG) synthesis in the intervertebral discs of young dogs exercised with long-distance running (40 km/day) were studied with a method based on image analysis of tissue sections. Ten dogs were run on a treadmill daily for 55 weeks, and 10 dogs from the same litters served as controls. The daily running distance gradually was increased to 40 km and was maintained at that level for the final 15 weeks. Midsagittal disc segments C7-T1, T8-9, and L1-2 were labeled with 35SO4, and histological sections of the segments were apposed against autoradiographic film to determine the synthesis of PGs. Next, the same sections were stained with safranin O to estimate possible alterations in PG concentration. The radiographs and stained sections were digitized with a flatbed scanner and measured by image analysis. The lumbar discs of runners displayed a significantly lower rate of 35SO4 incorporation, while a tendency toward enhanced incorporation was seen in the cervical and thoracic discs. Safranin O staining showed a pattern just opposite to 35SO4 incorporation: decreased staining in the cervical and thoracic discs and increased staining in the lumbar discs of the runners. The results demonstrate qualitatively different influences of long-term running training on PG metabolism at the cervical, thoracic, and lumbar levels in young dogs.

Animals↗
PubMed1993

Effects of cyclic hydrostatic pressure on proteoglycan synthesis in cultured chondrocytes and articular cartilage explants.

Primary chondrocyte cell cultures and explants of bovine articular cartilage were subjected to cyclic hydrostatic pressure in a novel computer-controlled pressure chamber designed for this purpose. The cultures were labeled with 5 microCi/ml 35SO4 and simultaneously pressurized with 5 MPa load for 1.5 or 20 h with pressure cycles of 0.0167, 0.05, 0.25, and 0.5 Hz. The chondrocyte cell cultures were also subjected to 0.0082 and 0.0034 Hz cycles. Sulfate incorporation was significantly inhibited in cell cultures subjected to the 0.5, 0.25, or 0.05 Hz cyclic loads for 1.5 h, but stimulated in explant cultures with a 0.5 Hz cyclic 1.5-h load. Chondrocyte cultures subjected to longer (20 h) loading showed a stimulation of sulfate incorporation with 0.5 and 0.25 Hz cycles, but an inhibition with 0.0167 Hz. The results indicate that cyclic hydrostatic pressures of presumably physiological magnitude have significant influences on proteoglycan synthesis in articular cartilage chondrocytes. Comparison of the cell and explant cultures under identical pressure conditions suggested that chondrocyte interactions with extracellular matrix are involved in this regulation by cyclic hydrostatic pressure. The responses of the chondrocytes to pressurization also varied according to the total length of the treatment, a finding compatible with the idea of multiple metabolic steps in chondrocytes, both pre- and post-translational, controlled by the ambient hydrostatic pressure.

Animals↗
PubMed1993

Effects of long-term running exercise on canine femoral head articular cartilage.

After long-term running program (40 km/day) anterior and posterior tissue samples from canine femoral head were labeled ex vivo in the presence of 35S-SO4. Sulfate incorporation rates did not differ between runner and control groups. The statistically significant changes in runners included a decreased uronic acid concentration (p < or = 0.02) and proportion of extractable proteoglycans (p < or = 0.05) as well as increased concentration of tissue uronic acid after 4 M GuCl extraction (p < or = 0.05) in the posterior area. These results support an idea of strengthened cartilage tissue after this kind of motion and load.

Animals↗
PubMed1993

Flat bed scanner in the quantitative assay of 35SO4-incorporation by X-ray film autoradiography of intervertebral disc sections.

A rapid quantitation of proteoglycan synthesis distribution in intervertebral disc and endplates is described. Tissue blocks of disc (C7-Th1) in the midsagittal plane from ten female beagles were incubated in the presence of 35SO4 and prepared as histological slides. For comparison, sulphate incorporation rates in the C5-C6 discs were assayed by liquid scintillation. Autoradiographic film exposed against the labelled sections was developed and digitized for image analysis using a 256 grey level flat bed table scanner connected to a microcomputer. The film density versus dpm (disintegrations per minute) calibration was performed using a set of 35SO4-labelled glycosaminoglycan standards applied on the same film. Since section thickness, dpm calibration of the film density and the specific activity of sulphate in the medium were known, the incorporations per tissue volume could be calculated. The average incorporation rates of the anterior and posterior annulus fibrosus, nucleus pulposus and vertebral endplates were 5.2 +/- 0.9, 5.2 +/- 0.8, 4.5 +/- 0.6 and 4.1 +/- 0.8 pmol/mm3 per h (+/- SE, n = 10), respectively and closely corresponded to those obtained by liquid scintillation. This method offers a convenient and reproducible way to measure the rate of proteoglycan synthesis in large tissue sections but also in thin cartilaginous tissues such as the vertebral endplate.

Animals↗
PubMed1993

Effects of aerobic long distance running training (up to 40 km.day-1) of 1-year duration on blood and endocrine parameters of female beagle dogs.

The effects of long distance running training on blood parameters, hormone responses and bone growth were studied in young growing dogs. A genetically uniform group of female beagles matched with respect to age and body mass were used. The runner dogs (n = 10) underwent gradually increased running exercise up to 40 km.day-1 on a treadmill with 15 degrees uphill gradient 5 days each week during a period of 1 year, while the littermate control dogs (n = 10) were kept in their cages throughout the study. Low plasma lactate concentrations of the runners measured immediately after the running training indicated the aerobic metabolism of the dogs while running. Significant decreases of blood haemoglobin concentrations (11%), blood erythrocyte number (10%), and erythrocyte packed cell volume (12%) were found in the runner group. Throughout the experiment, the value of thyroxine was slightly lower (13%) in the runners but no changes were found in tri-iodothyronine, free thyroxine, or cortisol serum concentrations. Serum oestradiol concentration at 56 weeks was significantly lower (42%) in the runner group than in the control group but was not as low (27%) at 70 weeks. Somatomedin-C concentration had decreased significantly by 37% at the age of 56 weeks in the runner group but was again at the level of the control dogs at the end of experiment (at 70 weeks). Ulna and radius bone mass as a ratio to the body mass had significantly increased in the runners. It would seem from our study that long distance running has a positive effect on bone growth.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Effect of running exercise on proteoglycans and collagen content in the intervertebral disc of young dogs.

Collagen and proteoglycans in the intervertebral disc (LI-II) of young beagle dogs (age 55 weeks) were analyzed following a 15 weeks' daily 20 km running training on a treadmill with 15 degree uphill inclination. In nucleus pulposus no statistically significant alterations were found in the content of proteoglycans or collagen. In annulus fibrosus the total tissue wet weight and total amount of collagen (hydroxyproline) increased by 34-36% in the runners as compared to age-matched, untrained controls. Since the total amount of proteoglycans did not increase, the annulus fibrosus became relatively depleted of proteoglycans, as indicated by the 27% reduction in uronic acid concentration, expressed either per wet weight or hydroxyproline. The average molecular size of the remaining nonaggregating proteoglycans was larger, and there was also a trend towards increased proportion of proteoglycans aggregating with hyaluronan. Most of the chondroitin sulfate side chains were 6-sulfated (65-66%). Running did not alter the sulfation or length of the chondroitin sulfate chains. The decreased proteoglycan/collagen ratio in annulus fibrosus may result in altered mechanical properties of the tissue and reflects its adaptation to enhanced motion and stress.

Animals↗
PubMed1993

Altered Golgi apparatus in hydrostatically loaded articular cartilage chondrocytes.

OBJECTIVES: Articular cartilage proteoglycan content is controlled by joint loading. This study aimed to elucidate the role of hydrostatic pressure in this regulation. METHODS: Primary cultures of chondrocytes from bovine articular cartilage, grown on coverslips, were subjected to 5, 15, or 30 MPa hydrostatic pressure, applied continuously or cyclically at 0.125 or 0.05 Hz. The Golgi apparatus was visualised either by a fluorochrome coupled wheat germ agglutinin or by transmission electron microscopy. Proteoglycan synthesis was studied by the incorporation of sulphur-35 labelled sulphate. RESULTS: After 30 MPa continuous hydrostatic pressure, the Golgi apparatus was observed in a compact form with a concomitant decrease in proteoglycan synthesis. The normal stacked appearance of the Golgi apparatus was no more visible in the electron microscopy preparation of the pressurised chondrocytes. This effect was reversible and was also noticed after 15 MPa continuous load, though to a minor extent. Cyclic pressures (5-30 MPa) caused no apparent change in the Golgi apparatus. The shape of some cells changed to a more retracted form after 30 MPa continuous pressure. Nocodazole, which causes disassembly of the microtubules, blocked the compacting influence of pressurisation on the Golgi apparatus, and reduced proteoglycan synthesis to about half of the control level. CONCLUSIONS: The packing of the Golgi apparatus is dependent on microtubules and may contribute to the inhibition of proteoglycan synthesis observed in articular cartilage subjected to high hydrostatic pressure.

Animals↗
PubMed1992

Quantitative study of articular cartilage and subchondral bone remodeling in the knee joint of dogs after strenuous running training.

All tissues of the joint are affected in some way in osteoarthritis because the joint is an interactively functioning unit. Our goal was to investigate the combined responses of articular cartilage and subchondral bone to altered loading conditions to improve our understanding of the physiology of these two components and, ultimately, the pathophysiology of osteoarthritis. A group of 20 female beagle dogs were divided pairwise into runners (n = 10) and controls (n = 10). The running training on a treadmill started at the age of 15 weeks, and during the following 40 weeks the running distance was gradually increased to 40 km/day with a 15 degree uphill inclination. With this daily running distance the beagles ran another 15 weeks. The samples for histology were taken from 11 different locations of the knee joint. Subchondral bone and articular cartilage histomorphometry was carried out in three different regions of the specimens (central, middle, and peripheral regions) using an image-analyzing system and an eyepiece graticule. In all regions of the articular cartilage, both the uncalcified and calcified cartilage showed slightly increased thickness in the runner dogs. The change was more evident in the peripheral and the central areas. The thickness of the subchondral bone plate tended to be higher in runners, too. Bone histomorphometric parameters showed significant signs of increased remodeling. The most notable change was the enlargement of the bone formation surface. The most intense remodeling was usually observed either centrally or peripherally in the articular surface. The strongest increase in trabecular bone volume and thickness of the cartilage was recorded in the femoropatellar area.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Local stimulation of proteoglycan synthesis in articular cartilage explants by dynamic compression in vitro.

Cultured bovine articular cartilage was subjected to 50 ms, 0.5-1.0 MPa compressions repeated at intervals of 2-60 s for 1.5 h and simultaneously labeled with 35SO4. The compression was delivered with a 4-mm-diameter nonporous loading head on an 8-mm-diameter cartilage explant. This method created directly compressed (central) and uncompressed (border) areas within the tissue. Analysis of the whole explant under a 0.5 MPa load showed significantly increased 35SO4 incorporation by compression repeated at 2- and 4-s but not at 20- and 60-s intervals. When the incorporation was studied separately in the border and central areas, a statistically significant stimulation was noticed in the central area with a 4-s cycle, while the border area was stimulated with a 2-s cycle. Autoradiography of the central area showed that the stimulation with 0.5 MPa and a 4-s cycle occurred through the whole depth of the cartilage, while raising the pressure to 1 MPa or the frequency to 2 s reduced the stimulation, particularly in the superficial cartilage. In the border area the stimulation with 0.5 MPa and a 2-s cycle was noted in the superficial zone only. The stimulation of proteoglycan synthesis is thus limited to certain loading frequencies and pressures and occurs in specific areas under and around the loaded site. Its rapid appearance suggests enhanced glycosylation or sulfation of core proteins or enhanced speed of posttranslational processing.

Animals↗
PubMed1992

Distribution of hyaluronan and its CD44 receptor in the epithelia of human skin appendages.

Biotinylated hyaluronan (HA) binding complex (HABC) from bovine articular cartilage proteoglycan was used as a histological probe to study the localization of HA in human skin. The distribution of HA was compared with its presumptive cell surface receptor, CD44, using monoclonal antibodies. In epidermis both HA and CD44 were found in the basal and spinous cell layers, but neither was present in the stratum granulosum and stratum corneum. In the keratinizing parts of hair follicles, i.e. in the outer and inner epidermal root sheath, pilosebaceous duct and the actual hair, HA and CD44 were found between the vital but not the terminally differentiated cells. In the sebaceous glands a small amount of HA was found around all cells, whereas CD44 was restricted to the basal cell layer. The secretory acini of the sweat glands stained intensively with anti-CD44 antibodies but only weakly with HABC. In the sweat gland, CD44 was localized on the basal and lateral surfaces of the clear cells, whereas the dark cells and the myoepithelial cells were negative. Both the lower and upper layers of the sweat gland ducts showed a faint but constant staining for CD44 and only minor amounts of HA. While in the keratinizing skin epithelia both HA and its CD44 receptor showed an intense staining with a close co-distribution, in the sweat and sebaceous glands their distribution patterns were not similar. It is suggested that in epithelia with divergent differentiation programs the functions of CD44 and HA may be different.

Biotin↗
PubMed1992

Proteoglycans synthesized by adult human epidermis in whole skin organ culture.

Adult human epidermis was cultured in whole skin organ culture under serum-free conditions in the presence of 35SO4. Proteoglycans (PG) comprised about 25% of the total (35SO4)-labeled material produced by epidermis. The rest of the incorporated activity displayed solubility characteristics typical of lipids. The molecular mass and the composition of the 35SO4-labeled epidermal PG and glycosaminoglycans (GAG) were studied using gel filtrations and agarose gel electrophoresis. The 35SO4-label of the epidermal PG was located in heparan sulfate (HS, approximately 75%) and chondroitin/dermatan sulfate (CS/DS, 25%), but not in keratan sulfate as determined by nitrous acid, chondroitinase AC II, chondroitinase ABC, and keratanase digestions, respectively. The molecular mass of the GAG chains was 10-40 kDa. The 35SO4-labeled PG were distributed between 60 and 600 kDa in agarose gel electrophoresis, with the highest activity at 350 kDa. Smaller activity peaks occurred at 150 and 60 kDa. Digestion of the PG with heparitinase removed most of the activity at 350 and 150 kDa, whereas chondroitinase ABC removed that at 60 kDa. A small amount of activity migrating between 600 and 1000 kDa was not affected by any of the GAG-degrading enzymes. Pulse chase experiments showed that the epidermal PG had an average half life of 24 h. The results thus demonstrate that human epidermis produces at least three different, rapidly metabolized PG. The PGs from 150 to 350 kDa contained heparan sulfate chains, whereas those at 60 kDa were chondroitin/dermatan sulfate PG.

Adult↗
PubMed1992

Articular cartilage thickness and glycosaminoglycan distribution in the canine knee joint after strenuous running exercise.

The influences of the strenuous running training program on the knee joint articular cartilage was studied in six female beagle dogs. At the age of 15 weeks, the dogs started running on a treadmill inclined 15 degrees uphill. Thereafter, the dogs were trained for 40 weeks, five times a week. For the final 15 weeks, the dogs ran 20 km/day. Six age-matched female beagles served as controls. The cartilage surfaces were intact after the running exercise. The training reduced the thickness of the uncalcified cartilage by 6% in the medial femoral condyle. The glycosaminoglycan concentration was reduced an average of 11% on the summits of the femoral condyles. The reduction was most pronounced (41%) in the superficial 50-micron cartilage zone. In other regions of the knee, such a decrease of glycosaminoglycans was not observed. A shift to strenuous running voided the increase in cartilage thickness and proteoglycan content previously observed after moderate running. Strenuous running induced marked depletion of proteoglycans from the superficial layer of the femoral condyles at sites subjected to highest impact loads.

Animals↗
PubMed1991

Correlations between hyaluronan and epidermal proliferation as studied by [3H]glucosamine and [3H]thymidine incorporations and staining of hyaluronan on mitotic keratinocytes.

The rates of keratinocyte proliferation and synthesis of Hyaluronan (HA) were studied in human whole-skin organ culture by labeling with [6-3H]glucosamine and [3H]thymidine, respectively, to reveal possible correlations between the two functions of the cell. HA distribution in epidermis was examined by staining with a specific probe prepared from cartilage proteoglycan. The keratinocyte proliferation rate was low on the first 2 culture days, but showed a tenfold increase on the third and fourth days while the synthesis of HA proceeded at a relatively stable level throughout the same period. The most intensive staining of HA occurred in the uppermost spinous cell layer, whereas mitotic cells resided in the basal and suprabasal layers. The keratinocytes under various stages of mitosis were surrounded by a HA staining not more intense than that around nondividing basal cells, but a thick pad of HA appeared rapidly between the daughter cells. These findings suggest that newly synthesized HA is associated with the separation of keratinocytes following mitosis but the majority of the synthesis and content of HA in epidermis is involved in other keratinocyte activities such as maintenance of the extracellular space and cell--cell interactions during migration and differentiation.

Adult↗
PubMed1991

Degradation of newly synthesized high molecular mass hyaluronan in the epidermal and dermal compartments of human skin in organ culture.

Human whole skin was labeled for 24 h with [6-3H]-glucosamine in organ culture and epidermis, dermis and culture medium were separately analyzed for the molecular mass and content of the [3H]-labeled hyaluronan (HA). Gel filtration on Sephacryl S-1000 of HA purified by HPLC showed a large proportion of the newly synthesized HA to be of a very high molecular mass (greater than 2 X 10(6) Da) in both epidermis and dermis, whereas HA in the medium was of a smaller size. After 24 h chase, most of the high molecular mass HA, and 42-48% of total labeled HA disappeared from both tissue compartments. The size of labeled HA recovered in the chase media was further reduced but the content roughly corresponded to that lost from tissue. The amount of unlabeled HA was not significantly altered in epidermis, whereas in dermis it was reduced to about 10% of the initial values during 5-d culture. The results demonstrate that HA of both epidermis and dermis is synthesized as a very high molecular mass compound but rapidly undergoes a limited degradation into large fragments. The fragmentation of HA is suggested to enhance its diffusion from the tissues, particularly dermis.

Adult↗