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Biomedical subjects

P Kolodziej

Publications and source records attributed to P Kolodziej.

At least 19 recordsLinked to original sources
PubMed2001

Outcome of subtalar arthrodesis after calcaneal fracture.

Between 1983 and 1995, we used subtalar arthrodesis to treat 16 consecutive patients for continued pain after an intra-articular calcaneal fracture. Average time to union was 3 months (2 to 4 months). Complications were minor in 4 patients, and major in 4 others. Length of follow-up in 14 patients was 55 months (range, 12 to 112 months). Hindfoot scores (clinical rating system of the American Orthopaedic Foot and Ankle Society) improved from 38 (range, 28 to 62) to 67 (range, 39 to 94). Results of medical outcome surveys indicate that patients had low scores in areas related to physical conditioning, physical role functioning, and bodily pain. We conclude that the majority of patients can have improvement with surgical reconstruction that addresses a specific problem, but pain relief is usually not complete.

Adult↗
PubMed2000

split ends encodes large nuclear proteins that regulate neuronal cell fate and axon extension in the Drosophila embryo.

split ends (spen) encodes nuclear 600 kDa proteins that contain RNA recognition motifs and a conserved C-terminal sequence. These features define a new protein family, Spen, which includes the vertebrate MINT transcriptional regulator. Zygotic spen mutants affect the growth and guidance of a subset of axons in the Drosophila embryo. Removing maternal and zygotic protein elicits cell-fate and more general axon-guidance defects that are not seen in zygotic mutants. The wrong number of chordotonal neurons and midline cells are generated, and we identify defects in precursor formation and EGF receptor-dependent inductive processes required for cell-fate specification. The number of neuronal precursors is variable in embryos that lack Spen. The levels of Suppressor of Hairless, a key transcriptional effector of Notch required for precursor formation, are reduced, as are the nuclear levels of Yan, a transcriptional repressor that regulates cell fate and proliferation downstream of the EGF receptor. We propose that Spen proteins regulate the expression of key effectors of signaling pathways required to specify neuronal cell fate and morphology.

Amino Acid Sequence↗
PubMed1999

Risk of avulsion of the Achilles tendon after partial excision for treatment of insertional tendonitis and Haglund's deformity: a biomechanical study.

Surgical treatment of posterior heel pain caused by insertional (calcific) Achilles tendonitis or retrocalcaneal bursitis includes resection of diseased tendon or exostectomy. Currently, no guidelines exist to determine how much tendon may be excised without risking rupture of the Achilles tendon. Anatomic dissections revealed the average height of the insertion measured 19.8 mm (range, 13-25 mm). Average width at the proximal aspect of the insertion measured 23.8 mm (range, 17-30 mm) and distally measured 31.2 (range, 25-38 mm). To assess the risk of avulsion, the tendon insertion was partially released in 25% increments of its measured height or width by one of the four methods: (1) from superior to inferior, (2) from the central portion outward, (3) from medial to lateral, and (4) from lateral to medial. Repeated cyclic loading of body weight x 3 was applied, and, if the tendon remained intact, the next 25% increment was released. This process was repeated until failure occurred. Failure occurred in all specimens by an oblique intratendonous separation or shear between the intact portion remaining on the calcaneus and the resected fibers remaining in the clamp. Fibers inserting into the bone did not avulse. Superior-to-inferior resection was found to be superior to the other three methods with eight of nine specimens remaining intact after 75% resection. We therefore conclude that superior-to-inferior offers the greatest margin of safety when performing partial resections of the Achilles insertion, and as much as 50% of the tendon may be resected safely.

Achilles Tendon↗
PubMed1998

Biomechanical evaluation of the schuhli nut.

The schuhli out is a device designed to lock an AO 4.5-mm cortical screw to a 4.5-mm dynamic compression plate independent of bony contact with the plate. The nut engages the screw below the plate, elevating the plate, and locking the screw at a 90 degrees angle, thus preventing toggling. Photoelastic modeling and biomechanical testing on sheep tibias were done to determine the mechanical properties of constructs using schuhli nuts. Use of schuhli nuts was shown to decrease stress in the bone below the plate. The initial axial stiffness of a construct fixed with schuhli nuts is less than a construct with standard screws, but the rate of loss of stiffness with cyclic loading is similar. When a cortical defect is present at the near cortex and the screw engages the far cortex only, the use of a schuhli nut significantly improves the stability of the construct compared with a standard screw alone, and behaves mechanically the same as a standard construct with intact cortices. This indicates that the schuhli nut acts as a substitute for a deficient cortex. The schuhli nut can be useful in osteoporotic bone because it prevents the screw from stripping the threads in the bone as the screw is advanced. It also serves to lock the screw to help prevent the screw from backing out. The schuhli nut may be a useful tool to improve stability in the treatment of complex fractures, reconstructions, or in pathologic bone.

Animals↗
PubMed1998

Kabuki syndrome.

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Abnormalities, Multiple↗
PubMed1997

Robin sequence.

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Humans↗
PubMed1997

Stickler syndrome.

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Chromosome Aberrations↗
PubMed1996

The relationship between loading conditions and fracture patterns of the proximal femur.

In an attempt to test the hypothesis of spontaneous hip fracture, seven pairs of femurs, with ages ranging from 59 to 90, were tested under two loading conditions designed to simulate muscular contraction. Simulated iliopsoas contraction produced femoral neck fractures at an average normalized ultimate load of 5.2 +/- 0.8 times body weight. Simulated gluteus medius contraction produced sub-/inter-trochanteric fractures at an average normalized ultimate load of 4.1 +/- 0.6 times body weight. The average ultimate load for all specimens was 3040 +/- 720 N. Fracture patterns produced by both loading conditions were clinically relevant. The results from this study suggest that abnormal contraction produced by major rotator muscles could induce hip fracture.

Aged↗