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H J Helminen

Publications and source records attributed to H J Helminen.

At least 127 records · Page 7Linked to original sources
PubMed1984

Morphometry of articular cartilage: a stereological method using light microscopy.

A stereological method is introduced for studying the light microscopic morphometry of articular cartilage. New parameters are presented for defining the three-dimensional structure of the articular cartilage. These include volume density of the lacunae and nuclei, numerical density of cells in 3-dimensional space, total number of cells, total volume of the lacunae in cartilage, volume and diameter of the lacuna and nucleus, the nucleus/lacuna volume ratio, and the mean volume of the matrix per cell. Using the lateral tibial condyle of the knee joint of eight rabbits, we investigated tissue preparation, sampling, morphometry, and the conditions necessary for validity and precision of the estimators. The method proved easy to use, and the estimators were precise.

Animals↗
PubMed1984

Quantitative morphological and biochemical investigations on the effects of physical exercise and immobilization on the articular cartilage of young rabbits.

The effects of physical exercise and immobilization on the knee joint articular cartilage of young rabbits (2.5 to 5 months of age) were investigated by quantitative histology, semiquantitative stereomicroscopy and scanning electron microscopy as well as biochemical methods, during a period of 8 weeks. Physical exercise increased the cell size in all zones of the uncalcified cartilage without notable concomitant change in the cell density. It also increased the volume density of the cells in the intermediate and deep zones. Increased striation of the cartilage surface was observed after 1 week's running period, suggesting superficial appearance of collagenous fibres and depletion of the proteoglycans on account of the exercise. However, after 4 to 8 weeks of running the increase of the striated surface was no longer significant. At the same time the proteoglycan content increased with preponderance of keratan sulfate-rich proteoglycans. Immobilization of the knee joint decreased slightly the cell size but increased the cell density in the superficial zone. Immobilization caused derangement of the smoothness of the articular surface already at the end of the 1st week with superficial splitting of the surface. Reduction of the cartilage matrix proteoglycans and collagen was observed after 1 week's immobilization. In the whole femoral surface, but not in the weight-bearing area of tibial lateral condyle, the proteoglycan content was replenished with chondroitin sulfate-rich molecules by the end of the 8th week after immobilization. Both physical exercise and immobilization caused significant intracondylar remodelling of the articular cartilage.

Animals↗
PubMed1984

Fixation, decalcification, and tissue processing effects on articular cartilage proteoglycans.

Neutral buffered 4% formaldehyde fixation for 48 h preserved well the proteoglycan content of bovine articular cartilage. Neither subsequent demineralization in 10% EDTA, nor light microscopic tissue processing, reduced the hexosamine or uronic acid content of the tissue. Fixation in alcoholic solutions increased Safranin O binding as well as periodic acid Schiff reaction of the cartilage matrix as measured by microspectrophotometry. It is suggested that the enhanced staining of cartilage was due to better preservation of the glycoprotein oligosaccharides. Quaternary ammonium salts in the fixative suppressed the staining of cartilage matrix with Safranin O.

Animals↗
PubMed1983

Semiquantitative analysis of rabbit knee articular surfaces based on stereomicroscopic examination of the cartilage.

A semiquantitative stereomicroscopic method was devised in order to examine rabbit knee articular surfaces. With the aid of a drawing tube mounted on a stereomicroscope, enlarged pictures (magnification of X 14-19) of ink-stained or SEM specimens of joint surfaces were drawn and the structural details classified. The point-counting method or a computer-coupled analyzer was used to analyze the pictures. The data thus obtained underwent statistical evaluation. The method proved to be very useful for the quantitation of experimentally induced changes on cartilage surfaces.

Anatomy↗
PubMed1983

Effects of immobilization for 6 weeks on rabbit knee articular surfaces as assessed by the semiquantitative stereomicroscopic method.

The effects of a 6-week immobilization period on rabbit knee articular cartilage surfaces were investigated by a new semiquantitative stereomicroscopic method following ink staining and processing for scanning electron microscopy. All surfaces of the immobilized knee joint were affected and displayed significant degenerative alterations. The knee joint contralateral to the immobilized one exhibited slight changes which could be interpreted as a sign of altered loading after immobilization. Articular surfaces of the patella and lateral condyle of the femur proved to be best suited for surface analysis on account of the small size, distinct borders and inherent evenness of the cartilage in non-treated animals.

Anatomy↗
PubMed1983

Investigation of articular cartilage surface morphology with a semiquantitative scanning electron microscopic method.

A semiquantitative scanning electron microscopic method for analysis of the articular cartilage surface morphology was developed. The method was based on a survey of large picture montages (ca. 70 X 100 cm) and classification of the cartilage surface changes at three levels. Computer technique was utilized in the analysis. The method ensured numerical expression and statistical treatment of the results. With this method we investigated the effects of physical exercise and immobilization on the articular cartilage of rabbit patella.

Animals↗
PubMed1982

Testosterone action on the ventral prostate lobe of the castrated rat as assessed with a stereologic morphometric method.

The effects of testosterone (1 mg testosterone propionate/100 g body weight for 30 days) on the ventral prostates of rats castrated 30 days prior to the onset of hormone treatment was investigated with a stereologic morphometric method. Testosterone induced rapid growth of the prostate, which was reflected by a 29-fold increase in acinar parenchyma but only a 2.6-fold increase in interacinar tissue. There was a 23-fold increase in the total amount of glandular epithelium and a 36-fold increase in total luminal amount. Various volumetric fractions, total surface area, total tubule length, height of the epithelium, mean diameter of the tubules, and mean distance between the tubules and between the glandular centers were calculated. Growth of the acinar parenchyma, especially of the glandular lumen, was the dominant pattern. We could not demonstrate any remarkable responses in the interacinar tissue during any phase of testosterone treatment.

Animals↗
PubMed1981

A histoquantitative study on the effects of castration on the rat ventral prostate lobe.

The effects of castration on the rat ventral prostate was studied utilizing an improved histoquantitative technique. Both volumetric fractions of the tissue compartments and their fractional weights, or, 'total amounts', were calculated during an observation period of 30 days. In addition, the surface area, length and mean diameter of the glandular tubules were recorded. The changes in the mean free distance between the tubules were recorded. The changes in the mean free distance between the tubules ('thickness' of the interacinar tissue) and the mean distance between the glandular centres were also determined. It was observed that the prostatic epithelium was quickly reduced in thickness after castration, to one half at day 2. Decline of the fractional amount of the lumen was slower; it also reached below the 10% level at day 30. The amount of interacinar tissue first increased at 12 hours by one third, but from then on decreased to one third of the normal amount. The 'thickness' of the stroma almost doubled, which was probably due to the sum of the simultaneous marked decline in the diameter of the tubules to one third of the original and the less striking reduction to two thirds of the mean distance between the glandular centres. The morphometrical method ensured the acquisition of a quantitative insight into the tissue processes involved in prostatic atrophy. Calculation of the fractional weights was regarded as especially invaluable, inasmuch as a growing body of evidence has been accumulated in favour of the crucial role of stromal-epithelial interactions in the differentiation, and growth, of the prostate.

Animals↗
PubMed1980

The rate of calcium extraction during EDTA decalcification from thin bone slices as assessed with atomic absorption spectrophotometry.

The rate of calcium extraction with EDTA (ethylenediamine tetraacetic acid) from thin bone slices (300 micrometer-3 mm thick) was determined by aid of an atomic absorption spectrophotometer. A 0.5 mm thick bone slice was completely decalcified with 15% (0.40 M), 8% (0.22 M), and 4% (0.11 M) EDTA in 24 h, 3 days, and 5 days, respectively (vol. 15 ml, temp. 4 degrees C, pH 7.4). At 37 and 60 degrees C the speed of demineralization was slightly increased as compared with that at 20 degrees C, while no difference was observed between 4 and 20 degrees C. Bone slices with a thickness of 0.3, 0.5, 1 and 2 mm were decalcified -- in the same order -- in 24 h, 2, 3, and 5 days (8% EDTA, 4 degrees C, pH 7.4). At pH 7.4, the decalcification rate was a little slower than at pH 5.0 and 8.5. Agitation did not affect the decalcifying velocity, nor did the volume of the agent, except when the volume was very small. The demineralization of ordinary bone, containing both compact and spongy bone, was found to be more rapid than that of homogeneous bone reported earlier. The acidic buffers and New Decalc, which served as reference substances, exerted a more vigorous decalcifying effect thatn EDTA. K formate/formic acid buffer, pH 3.15, demineralized a 1 mm thick bone slice in 24 h and 2 days was needed with Na lactate/lactic acid buffer, pH 3.70. With New Decalc, pH 0.9, the corresponding demineralization was accomplished in 1.5 h. Atomic absorption spectrophotometer proved to be a useful tool in the evaluation of calcium extraction velocity from bone slices.

Animals↗
PubMed1980

An improved light microscopical histoquantitative method for the stereological analysis of the rat ventral prostate lobe.

An improved light microscopical histoquantitative method for the analysis of the stereologic structure of the ventral lobe of the rat prostate is introduced. From paraffin-embedded tissue sections, volumetric fractions of the acinar parenchyma, the glandular epithelium, the glandular lumen, and the interacinar tissue were determined. The surface density of the glandular epithelium and the length density of the glandular tubules per cubic millimeter of tissue were also calculated. The corresponding total amount/quantity of each tissue compartment was computed for the whole ventral lobe based on the weight of the lobe. Using established stereologic laws, the height of the epithelium, the diameter of the glandular tubules, the free distance between the glandular tubules, and the distance between the glandular centers (means) were determined. The fitness of the method was tested by analyzing, in addition to normal prostates, ventral prostates of rats castrated 30 days before sacrifice.

Animals↗
PubMed1979

The effects of various fixatives on the relative thickness of cellular membranes in the ventral lobe of the rat prostate.

A desitometric method was utilized in the measurement of the relative thickness of the cellular membranes in the ventral lobe of the rat prostate. Potassium permanganate, glutaraldehyde, osmium tetroxide, and ruthenium tetroxide solutions were used as fixatives. During preparation for electron microscopy, the tissues were given standardized treatments to reduce methodological errors; latex particles were applied to the thin sections to serve as reference particles of a known size. The most remarkable observation of the study was that the densitometric method yielded reproducible results and that the different fixatives gave significantly different values for the relative thickness of cellular membranes. Glutaraldehyde, or glutaraldehyde followed by ruthenium tetroxide post-fixation, gave the highest values for membrane thickness, while osmium tetroxide and potassium permanganate gave the lowest values. Glutaraldehyde treatment, prior to osmium tetroxide or potassium permanganate post-fixations, rendered the membranes thicker than after osmium tetroxide and potassium permanganate treatments alone. Ruthenium tetroxide appeared to be very suitable for fixation of cellular membranes.

Animals↗
PubMed1979

The relative thickness of intracellular membranes in epithelial cells of the ventral lobe of the rat prostate.

The relative thickness of intracellular membranes of epithelial cells in the ventral lobe of the rat prostrate was measured by a densitometric method. Glutaraldehyde perfusion followed by ruthenium tetroxide immersion fixation appeared to be the most suitable method for membrane thickness measurements. By thickness, the membranes could be roughly subdivided into three groups. The inner and outer membranes of the mitochondrion made up the thinnest membranes of the cell. The second group of membranes consisted of the membranes of the rough-surfaced endoplasmic reticulum and the Golgi apparatus, the different faces of the latter organelle, and the Golgi vesicles. The thickest group of membranes included those of the cell membrane, secretory granules, condensing vacuoles, lysosomes, autophagic vacuoles and multivesicular bodies. The differences in thickness of the membranes are probably due to the varying protein/lipid ratio, and the qualities and proportions of the different lipids in the membranes.

Animals↗