Search PubMed⌕ Search

Biomedical subjects

H Steen

Publications and source records attributed to H Steen.

67 records · Page 4Linked to original sources
PubMed1985

Morphological changes in continuously stretched skeletal muscles in sheep.

The effects of continuous elongation of skeletal muscles were studied on six sheep who underwent a lengthening osteotomy of the right tibia. Open muscle biopsies were taken from the biceps femoris muscle preoperatively (Group A), after 5 weeks of bone distraction (Group B) and after another 5 weeks without further distraction (Group C). The size and distribution of type 1 (slow-twitch) and type 2 (fast-twitch) muscle fibres were determined from sections stained for myofibrillar ATPase activity. All sections were also evaluated by light microscopy, especially with regard to myopathic changes. The type 2 fibres showed a significant decrease in size from group A to B and from group B to C. The reduction in fibre size from group A to C was 44.2%. The type 1 fibres, on the other hand, showed no significant differences in mean fibre size between the groups. However, there were considerable individual variations in type 1 fibre size between the groups. The distribution of both fibre types was similar in groups A and B (appr. 17% type 1 fibres) whereas the relative number of type 1 fibres was reduced to 12.4% in group C (P less than 0.01). Myopathic changes, i.e. muscle fibre necroses, were not seen in any of the groups. It is concluded that the type 2 fibre atrophy is mainly caused by muscular inactivity during the postoperative period, but an additional effect of continuous stretching of the muscle cannot be excluded.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Spinal deformities in tall girls.

In a prospective study, 62 girls who consulted the paediatric department because of tall stature were examined for spinal deformities. Thirteen cases of scoliosis measuring 10 degrees or more were found. Eighteen girls had a thoracic kyphosis of more than 40 degrees and 11 had additional vertebral abnormalities indicating Scheuermann's disease. The incidence of scoliosis and Scheuermann's disease was much higher in our material than normal.

Adolescent↗
PubMed1981

A microassay for quantitatively detecting the Epstein-Barr virus receptor on single cells utilizing flow cytometry.

A quantitative microassay for detecting and analyzing the Epstein-Barr virus receptor (EBVR) utilizing fluorescein-conjugated virions is presented. The test is virus substrain-specific. Both the B95-8 and P3HR-1 strains were labelled and adsorbed to a variety of targets. Relative binding of virus was assessed by flow cytometry, the results being directly comparable with those obtained by earlier methods. Cell size and cellular DNA content were measured simultaneously with virus binding, thus enabling us to calculate EBVR density and to correlate receptor synthesis and cell cycle stage.

Cell Line↗
PubMed1981

Spontaneous (H)-thymidine uptake in histological subgroups of human B-cell lymphomas.

Spontaneous (3H)-TdR incorporation was studied in cell suspensions from 64 patients with monoclonal B-cell neoplasias. Among various incubation periods a long-term (20 h) assay with (3H)-TdR had the greatest discriminatory power versus non-neoplastic lymph node cell suspensions. The (3H)-TdR uptake correlated positively with cell volume, nuclear volume, and cells in S + G + M phase of the cell cycle. A high degree of heterogeneity with regard to (3H)-TdR incorporation was found within several histological groups of the Kiel classification, especially in low-grade malignant lymphomas of centroblastic/centrocytic origin and in the lymphoplasmacytoid groups. In highly malignant lymphomas (3H)-TdR uptake was statistically, significantly higher than in lymphomas of low-grade malignancy. Patients with localized disease (stages I and II) and those with "B'-symptoms showed increased incorporation of radioactive thymidine as compared to patients with disseminated mined by histopathology and spontaneous uptake of (3H)-TdR.

Adult↗
PubMed1976

X-ray-induced luminescence and optical absorption in DNA films.

For DNA films, X-irradiated at 77 K, a comparative study was performed on (a) light emission (fluorescence and phosphorescence) during irradiation, (b) afterglow and thermoluminescence, (c) optical absorption after irradiation, and (d) free-radical reactions in similar gamma-irradiatied DNA samples. Spectra are reported for the various kinds of light emission and for the optical absorption. From temperature-dependence studies, it was concluded that the light-emission phenomena are unrelated to the reactions of the free radicals as studied by electron paramagnetic resonance. The optical absorption on the other hand, is strongly correlated to the presence of free radicals in the DNA. Some mechanisms possibly involved in the observed luminescence reactions are discussed.

DNA↗
PubMedDate not supplied

Four-strand hamstring tendon autograft compared with patellar tendon-bone autograft for anterior cruciate ligament reconstruction. A randomized study with two-year follow-up.

Seventy-two patients with subacute or chronic rupture of the anterior cruciate ligament were randomly assigned to autograft reconstruction with four-strand gracilis and semitendinosus tendon (N = 37) or with patellar tendon-bone (N = 35) from the ipsilateral side. The groups were similar in terms of age, sex, level of activity, degree of laxity, meniscal lesions found surgically, and rehabilitation program. The follow-up was performed at another hospital by independent observers after 6, 12, and 24 months. Sixty-one patients (32 with hamstring tendon grafts and 29 with patellar tendon grafts) complied with the follow-up routine for the full 24 months. No differences were found between the groups with respect to Cincinnati functional score, KT-1000 arthrometer measurements, or stairs hopple test results. The subjective result and the single-legged hop test result were better for the hamstring tendon group after 6 and 12 months, but no differences were found after 24 months. The hamstring tendon group showed better isokinetic knee extension strength than did the patellar tendon group after 6 months, but not after 12 and 24 months. There was a significant weakness in isokinetic knee flexion strength among the hamstring tendon group. Anterior knee pain was not significantly different between the groups, but kneeling pain was significantly less common in the hamstring tendon group after 24 months.

Adolescent↗
PubMedDate not supplied

The effect of knee bracing after anterior cruciate ligament reconstruction. A prospective, randomized study with two years' follow-up.

The purpose of this prospective, randomized, clinical trial was to evaluate the effect of knee bracing after anterior cruciate ligament reconstruction. Sixty patients were randomized into one of two groups: Patients in the braced group wore rehabilitative braces for 2 weeks, followed by functional braces for 10 weeks, and patients in the nonbraced group did not wear braces. Data were recorded preoperatively, and postoperatively after 6 weeks, 3 and 6 months, and 1 and 2 years. The following outcome measures were used: KT-1000 arthrometry, the Cincinnati knee score, goniometry to record range of motion, computed tomography to determine thigh atrophy, Cybex 6000 isokinetic testing to evaluate muscle strength, three functional knee tests, and a visual analog scale to evaluate pain. At all follow-up times there were no significant differences between the two groups with regard to knee joint laxity, range of motion, muscle strength, functional knee tests, or pain. However, the Cincinnati knee score showed that patients in the braced group had significantly improved knee function compared with patients in the nonbraced group at the 3-month follow-up, even though the braced group showed significantly increased thigh atrophy compared with the nonbraced group at 3 months.

Adolescent↗
PubMedDate not supplied

Growth retardation after experimental limb lengthening by epiphyseal distraction.

Growth retardation occurring as a result of limb lengthening by epiphyseal distraction in two animal species was quantified by using femur or tibia as the experimental bone. The growth plate subjected to distraction appeared radiolucent after the lengthening procedure but was less distinct and had reduced height as compared with the control. In seven of 22 animals, the growth plate of the lengthened bone appeared to close earlier than in the control. After lengthening, bilateral longitudinal growth was evaluated semiquantitatively from radiographs until growth had ceased or residual growth was negligible. Growth retardation was consistently experienced in all animals, with an average reduction in growth potential of each study ranging from 40 to 70%. The results show that epiphyseal distraction is a valid method of limb lengthening, but it appears to have a consistently harmful effect on the growth plate and should be used clinically only in patients close to maturity.

Age Factors↗
PubMedDate not supplied

Clinical estimation of ilizarov fixator axial stiffness based on wire and half pin contributions.

A key parameter in the mechanical environment created in distraction osteogenesis is the axial stiffness of the external fixator. Mechanical testing of the frames with wire and half pins has been used to estimate the stiffness contributions of wires based on the span length and of half pins based on the offset length. A summation of the wire and half pin contributions appears to represent a suitable estimate for the axial stiffness of frames composed of a mixture of wires and half pins. Using this estimate, clinicians can make informed decisions regarding frame construction, and it may be possible to investigate the rate of bone formation relative to axial frame stiffness in the clinical setting.

Biomechanical Phenomena↗