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O Svensson

Publications and source records attributed to O Svensson.

At least 91 records · Page 5Linked to original sources
PubMed1989

The parathyroid glands in the rat as seen by ultrathin step and serial sectioning.

Parathyroid cells exhibit ultrastructural heterogeneity. This has been interpreted as an indication that the cells are undergoing secretory cycles, varying in synthetic activity. By electron microscopy we examined step sections at 1 and 2 micron intervals and serial sections of parathyroids from normocalcemic rats of three different age groups. The secretory cells in all three age groups exhibit structural polarity: nuclei and secondary lysosomes are generally located towards the interstitial tissue, whereas the Golgi is confined mainly to regions in the interior of the cell sheets. Cell surfaces facing the interstitial tissue are smooth, whereas plasma membranes in the interior of the cell sheets form tortuous areas. Consequently, an individual cell profile may show quite different appearance depending on section level. Our results do not support the concept that the observed heterogeneity is necessarily due to differences in organelle contents between the cells. The present investigation thus offers an alternative explanation to the ultrastructural variability among secretory parathyroid cells in the rat.

Animals↗
PubMed1989

Peptostreptococcus magnus does not cause hematogenous infections in experimental arthroplasties.

Rabbits with cemented endoprostheses in the knee joints were given 1-ml intravenous injections of suspensions containing Peptostreptococcus magnus (3 x 10(8) colony-forming units/ml) on three consecutive days seven weeks postoperatively. The animals were killed after another seven weeks. The bacterial challenge did not result in infection. This is in contrast to a previous study using the same experimental system with another anaerobic bacterial species, Propionibacterium acnes, which caused infection in approximately 50% of the animals. Both these bacteria have previously been reported to cause late infections in human arthroplasties. The present results may indicate differences in the spreading mechanisms, i.e., that Peptostreptococcus magnus may have a limited ability to cause hematogenic infections and that late infections of endoprostheses by Peptostreptococcus magnus are due to perioperative contamination.

Animals↗
PubMed1988

Stereological studies of the parathyroids in the young rat with hypercalcemia induced by severe phosphate depletion.

In order to suppress the parathyroid glands by inducing hypercalcemia, young rats were fed a diet containing a low (0.02%) phosphate content. After 28 days blood samples were taken for estimation of serum calcium, phosphate and immunoreactive parathyroid hormone levels. Both parathyroids from each animal were subjected to serial sectioning so that the total glandular volume could be calculated by light microscopy. Volume and surface densities of cells and organelles were measured according to conventional stereological principles, so that the total volumes and surface areas could be estimated. Phosphate depletion caused marked growth retardation. The animals also developed hypophosphatemia, but in spite of pronounced hypercalcemia the levels of circulating immunoreactive parathyroid hormone remained unchanged. The volume of the parathyroids was reduced, but only to an extent commensurate with the reduced body mass. In the experimental group the volume density of cells was unchanged, but that of nuclei was increased; the volume density of Golgi complexes was reduced. The densities of the other cell components measured, namely the volume density of mitochondria and the surface densities of secretory cells, nuclear membranes and rough endoplasmic reticulum were unchanged. When the volumes and surfaces were expressed in absolute terms and related to total body mass, no differences between the groups were apparent.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Adrenaline-induced changes in serum electrolytes, ECG, and blood pressure, with Ca-blockade pretreatment.

Adrenaline infusions (AI) (0.5 micrograms adrenaline per 10 kg body weight per minute over 120 minutes) were given weekly for three weeks to 20 healthy male volunteers aged twenty-one to thirty-eight years. The AI was given after three days' treatment with diltiazem (D), verapamil (V), or placebo (PI) in a single-blind fashion. After pretreatment with Pl, serum potassium (s-K) decreased from 3.93 +/- 0.30 mmol/L (M +/- SD) to 3.33 +/- 0.31 (P less than 0.001) with the greatest change 69.75 +/- 46.24 minutes after the start of the AI. Corresponding values for s-Mg were 0.84 +/- 0.06 to 0.78 +/- 0.05 (P less than 0.01) and 106.50 +/- 36.71 minutes, for s-Ca 2.40 +/- 0.07 to 2.30 +/- 0.08 (P less than 0.01) and 103.50 +/- 36.06 minutes, for s-P 1.05 +/- 0.17 to 0.91 +/- 0.17 (P less than 0.02) and 80.25 +/- 47.25 minutes, and for s-urate 344.79 +/- 50.55 to 329.26 +/- 47.80 (P greater than 0.05) and 63.95 +/- 46.05 minutes. After pretreatment with D, AI produced similar electrolyte changes as after Pl, but the rise in blood glucose was slightly more pronounced and the drop in s-urate less pronounced. The heart rate (HR) before AI after pretreatment with D was lower than after Pl, but the increase during the AI was of the same magnitude. The AI-induced changes in systolic (SBP) and diastolic (DBP) blood pressure after D did not differ significantly from those seen after Pl, and neither did QT and QTc, whereas the PR duration was prolonged (0.18 +/- 0.03 second) when compared with Pl (0.16 +/- 0.02) (P less than 0.05). Although the magnitude of the change in DBP was not influenced, V prolonged the time till the lowest DBP (48.95 +/- 26.38 minutes) when compared with Pl (31.50 +/- 29.16 minutes) (P greater than 0.05). The other variables followed the same pattern as for D. In conclusion AI in healthy volunteers produced a drop in s-K but in addition a drop in s-Mg and s-Ca, the latter appearing later than the drop in s-K. Pretreatment with diltiazem and verapamil did not influence the magnitude of these changes but reduced the drop in s-urate.

Adult↗
PubMed1988

Cervical instability in skeletal dysplasia. Report of 6 surgically fused cases.

Six patients with skeletal dysplasias complicated by deformity or instability of the cervical spine were reviewed. Three patients had congenital spondyloepiphyseal dysplasia and 1 each suffered from Morquio's syndrome, pseudoachondroplasia, and chondrodystrophia calcificans congenita. Four patients had myelopathy of varying severity from slight weakness of one leg to tetraplegia. At a mean age of 6 (3-11) years, they underwent posterior fusion and immobilization in a halo brace. In all the cases the extent of postoperative neurologic recovery was, however, limited. Our cases illustrate the need of early diagnosis and fusion of cervical instability.

Atlanto-Axial Joint↗
PubMed1988

Effect of calcium depletion on the rat parathyroids.

Stereological methods were used on the light- and electronmicroscopic levels to estimate total volumes and surfaces of secretory cells and organelles in normal and hypocalcemia-stimulated rat parathyroid glands. Weanling rats were given a diet containing 0.02% Ca. After 28 days they had severe hypocalcemia and about a two-fold increase of serum levels of immunoreactive parathyroid hormone. The parathyroids were enlarged, mainly because of an increase of cytoplasmic volume of secretory cells. Volume and surface densities (fractions) of cells and organelles were, however, only moderately increased. But when expressed as absolute amounts, the volumes and surfaces of the cell components showed a substantial increase. The largest changes occurred in total volume of Golgi complex and total surface of endoplasmic reticulum, which both showed a more than two-fold increment. The present investigation provides quantitative histological data showing that pronounced hypocalcemic stimuli may cause an increase in the machinery involved in synthesis and processing of parathyroid hormone.

Animals↗
PubMed1987

The parathyroid gland in metal rickets. A stereological study.

Rickets can be induced by oral administration of metals. A depressive effect exerted by metal ions on the parathyroid gland has previously been suggested to be a pathogenetic factor in strontium-induced rickets. In the present investigation, rickets was induced in young rats by oral administration of strontium and manganese, respectively. The parathyroids were fixed by perfusion and the total volume of the parathyroid glands was determined by serial sectioning. Conventional stereological techniques were applied on the ultrastructural level and the densities obtained could be related to the total mass of parathyroid tissue. In both rachitic groups the volume of the parathyroid glands as well as the absolute amounts of all cellular components studied, were reduced. All these changes were, however, correlated to the decreased body weight of the experimental animals. This is well in line with the finding of unaltered serum concentrations of calcium and immunoreactive parathyroid hormone. Therefore, it is concluded that the parathyroids do not play an important role in the pathogenesis of metal rickets.

Animals↗
PubMed1987

Orthopaedic infections by Serratia marcescens: a report of seven cases.

In recent decades, Serratia marcescens has been established as a cause of infections difficult to treat, and several outbreaks of nosocomial infections have been reported, mostly from the USA. However, serratia infections affecting bones and joints are very rare; only a few such cases have previously been reported from Europe. We report 7 patients with orthopaedic infections by S. marcescens chiefly of nosocomial origin where previous antibiotic therapy apparently was a predisposing factor. The clinical course was generally protracted, often requiring repeated surgical interventions. Also, in some cases adequate therapy was considerably delayed as serratia was considered to be a nonpathogenic saprophyte. Multiresistance to antibiotics was a major clinical problem. However, the third generation cephalosporins are often effective against serratia and the aminoglycosides can thus be avoided. The increased use of prophylactic antibiotic therapy in orthopaedic surgery may bring about an increase in the incidence of infections by multiresistant microorganisms in orthopaedic wards.

Adult↗
PubMed1987

Effects of low-frequency components and analog filtering on auditory brainstem responses. A comparison of analog and digital filtering.

Analog and digital filtering of ABR (Auditory Brainstem Response) is compared for 20 adults with normal hearing. The result shows that the shape of the ABR is changed by the non-linear phase function of the analog filter (350-1,700 Hz). Peaks IV and V are particularly affected. The result also shows that if peaks IV and V are to be identified with certainty it is sometimes necessary to raise the lower band limit of the filter. This is because the low-frequency part of the ABR interferes with peaks IV and V. The latencies of peaks I to V obtained from ABRs after digital and analog filtering have been compared. This showed small but significant differences.

Adult↗
PubMed1987

Manganese rickets. A biochemical and stereologic study with special reference to the effect of phosphate.

Oral administration of manganese (Mn) to young rats results in morphologic changes in the growth plate histologically resembling rickets. Previous investigations have indicated that one important factor in the development of Mn rickets is phosphate depletion, because of the precipitation of insoluble manganese phosphate in the gut. In the present study, the morphologic and biochemical changes in rickets induced by phosphate (P) depletion per se as well as in florid and healing Mn rickets were investigated. Rachitic changes were induced in young rats by giving dietary Mn (2%) or by phosphate depletion (0.02% P) for 25 days. The rachitic changes of the proximal tibial growth plate were quantitated with the use of stereologic methods. In addition, the growth plates were dissected into one upper and one lower part and proteoglycans were separately extracted with 4 M guanidine hydrochloride and purified by ultracentrifugation. In rats given phosphate in more than equimolar amounts relative to Mn, the rachitic changes were abolished. When rats with florid Mn rickets were given standard rat food, containing 1% P, rapid healing ensued. Moreover, similar rachitic changes were obtained by phosphate depletion alone. Proteoglycans from the lowermost tissue portion of rachitic growth plates readily formed aggregates with hyaluronic acid and also contained larger chondroitin sulphate chains than controls. Upon healing, these changes tended to normalize. The data support the concept that phosphate depletion is crucial in the pathogenesis of Mn rickets. Also, it seems that the biochemical changes in different forms of rickets are of a similar kind, which further underlines the importance of proteoglycans in enchondral bone formation.

Animals↗
PubMed1986

Shoulder joint load and muscular activity during lifting.

The aim of this study was to investigate load on shoulder joint and muscles in healthy adults during four different ways of lifting a moderate burden (12.8 kg) from floor to table level. The methods used were surface electrode EMG with linear envelope, and calculation of loading moments of force using a static biomechanical model. The shoulder load at the beginning of the lift was lowest for the straight knee lift. The peak load occurred in the late phase of all lifts. On completion of the lift, load and activation were considerably lower when the subject was allowed to step forward before putting the box down. The most activated shoulder muscles were the anterior and lateral parts of the deltoid, and the serratus anterior. Around 80% of the shoulder load moment was caused by the weight of the burden. Some 75% of maximum shoulder strength was required for lifting the burden.

Adult↗