Biomedical subjects
Publications and source records attributed to H De Boeck.
Seven patients treated by open reduction through a single posterior approach and internal fixation with an AO T-plate for displaced posteromedial fracture of the tibial plateau were reviewed. Followup ranged from 1 to 10 years, and all patients had excellent or good results, and there were no complications caused by the method of treatment.
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Several classifications of hip fractures have been proposed in the literature. The usefulness of classifications of hip fractures was examined between Belgian Orthopaedic and General Surgeons. Garden's classification of subcapital fractures is the most widely adopted system. Simple anatomic identification is preferred by 64.9 per cent for intertrochanteric fractures and by 78.7 per cent for subtrochanteric fractures. Classifications of fractures for clinical research are considered necessary by 89.4 per cent but there is no universally accepted system. Radiographs of 5 hips were classified by 10 colleagues using the AO Classification system. No fracture was classified identical by all observers. This confirms earlier studies that observers had a poor ability to classify hip fractures according to a given classification system.
A case of spontaneous dislocation of the tibialis posterior tendon in a 12-year-old boy is presented. Closed reduction under general anaesthesia was performed, and after immobilisation for 6 weeks in a plaster cast no recurrence was observed. This case illustrates an unusual case of habitual dislocation of the tibialis posterior tendon treated by conservative means.
I reviewed 17 children with overriding of the fifth toe, treated by Butler's arthroplasty; 6 underwent bilateral operation. Satisfactory results were obtained in all but 1 patient, and all could wear normal shoes.
The interactions of a series of saturated diacylglycerols (DAGs) with fatty acid side chain lengths of 6-14 carbons with multilamellar phospholipid bilayers consisting either of dipalmitoylphosphatidylcholine (DPPC) or of a mixture of DPPC and bovine liver phosphatidylcholine (BL-PC) extracts were studied by 2H NMR spectrometry. We found that the perturbation induced by the DAGs into the bilayer structure strongly depends on the length of the DAG fatty acid side chain. Shorter chain 1,2-sn-dihexanoylglycerol and, to a larger degree, 1,2-sn-dioctanoylglycerol (diC8) induce transverse perturbation of the bilayer structure: the order parameters of the phospholipid side chains are increased by the intercalating DAG molecules in the region adjacent to the phospholipid headgroups and decreased toward the terminal methyls, corresponding to the bilayer interior. The longer chain DAGs (C greater than or equal to 12) studied in this and previous [De Boeck & Zidovetzki (1989) Biochemistry 28, 7439] work induce lateral phase separation of the lipids into DAG-enriched gellike domains and relatively DAG-free regions in the liquid-crystalline phase. Each of the DAGs studied induces a decrease in the area per phospholipid molecule, and a corresponding increase in the lateral surface pressure of the bilayers.(ABSTRACT TRUNCATED AT 250 WORDS)
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A sodium-iodide scintillation probe and a portable scaler rate-metre were used to localize small bone tumours at operation, after the preoperative injection of technetium-99m methylene diphosphonate. This technique allows complete removal of the tumour nidus of an osteoid osteoma or the active part of other lesions without undue sacrifice of the surrounding bone. The method has been used for successful relief of pain in thirteen patients.
Non-union of the ulnar diaphysis after isolated ulnar shaft fracture is uncommon. Complications due to non-union of the ulna must therefore be very rare. A case of a stress fracture of the radius in a postmenopausal woman following an isolated ulnar shaft fracture and non-union is presented. The mechanism of the stress fracture and propositions for preventing non-union of the ulnar shaft after an isolated fracture in the osteoporotic patient are discussed.
(S)-1-[3-Hydroxy-2-(phosphonylmethoxy)propyl]cytosine (HPMPC) is an antiviral phosphonate nucleotide analogue that displays activity against a range of herpesviruses. Anion exchange high performance liquid chromatography analysis of the 60% methanol extract from [14C]HPMPC-treated cells reveals the formation of three major metabolites. Two of these were identified as phosphorylated forms of HPMPC, HPMPC phosphate, and HPMPC diphosphate, by liberation of HPMPC upon acid digestion and coelution with synthetic standards on high performance liquid chromatography. The third metabolite, which is resistant to alkaline phosphatase cleavage but sensitive to phosphodiesterase, is proposed to be an HPMPC phosphate adduct. In herpes simplex virus-1-infected cells the same three metabolites are detected, at concentrations comparable to those in uninfected cells. When HPMPC is removed from the medium, the concentrations of the metabolites in cells decrease slowly, with half-lives of approximately 6, 17, and 48 hr for HPMPC phosphate, HPMPC diphosphate, and the HPMPC phosphate adduct, respectively. HPMPC diphosphate inhibits herpes simplex virus-1 and -2 DNA polymerases with a lower Ki than that for DNA polymerase alpha, and enzyme inhibition is competitive in each case. The formation and the persistence of HPMPC phosphates in cells and the selective inhibition of viral DNA polymerases by HPMPC diphosphate can explain why cells pretreated with HPMPC remain refractory to viral infection even long after HPMPC is removed from the medium.
In a prospective study, 28 consecutive patients with an acute Type V acromioclavicular sprain were treated with a coraco-clavicular repair using a double velour Dacron graft. All patients were reviewed after a mean follow-up period of 5.1 years (range: 1 to 9 years). At follow-up, 20 patients (71.4%) showed good or excellent results, according to the Imatani evaluation system, and 8 patients (28.6%) demonstrated a fair or poor result according to the same system. Loss of reduction was encountered in 11 shoulders (40%), despite an initial anatomical reduction. No correlation was seen between the overall scores at follow-up and the degree of residual dislocation, between the overall scores and the presence of coraco-clavicular calcifications or ossifications, between the overall scores and the development of posttraumatic arthritic changes, or between the overall scores and the presence of osteolysis of the distal clavicle.
Nonunion is a very rare complication of a comminuted intra-articular wrist fracture treated by external fixation. The authors describe the likely reasons and the after-care, in order to avoid this complication.
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We report a case of a nonunion of a carpal scaphoid in a child treated successfully by cast immobilization. Contrary to the general opinion that nonunion of the scaphoid bone should be treated operatively, even in children, we showed that healing can be obtained by nonoperative treatment methods.
We treated 101 consecutive patients with Frykman type III, IV, VII and VIII fractures of the distal radius and ulna with the small Hoffman external fixator between 1986 and 1989. All patients were reviewed after a mean follow-up period of 22 months (range: 12 to 45 months). At follow-up, 88 wrists (87%) were rated good or excellent, according to the demerit point system, and 13 wrists (13%) were rated fair or poor according to the same system. A highly significant correlation (p less than 0.01) was found between the overall scores at follow-up and the grade of postoperative articular incongruity, between the overall scores and the grade of osteoarthritis at follow-up, between the grade of postoperative articular incongruity and the grade of osteoarthritis at the follow-up, as well as between the overall scores and the grip strength at follow-up. A significant correlation (p less than 0.05) was found between the length of follow-up and the grade of osteoarthritis at follow-up. Although the complication rate was rather high (40%), most of these problems were minor, transient and pin-related.
Osteosarcoma is the most frequent primary malignant bone tumor. It usually occurs in the second decade of life. Pathologic fracture as the primary manifestation of an osteosarcoma is rather unusual, especially under the age of 10. The authors present the case of a 9-year-old boy with a diaphyso-metaphyseal femoral fracture, in whom the radiological features of an osteosarcoma were not recognized at the time of the fracture as they were not clearly visible, and at follow-up initially were considered as proliferative callus formation.
We report a case of ossifying fibroma of the long bones (OFLB). This lesion, occurring mainly during the first decade of life, typically affects the tibial diaphysis and clinically presents as a painless bony enlargement. Radiographic features include an osteolytic cortical expansion, containing diffuse calcifications, and separated from the medullary by a thick cortical rim. CT appears to be the examination of choice to define these signs and permits differentiation from monostotic fibrous dysplasia and from adamantinoma (by demonstrating the presence or absence of diffuse high attenuation values). The importance of making the differential diagnosis is stressed, as prognosis and management of OFLB, fibrous dysplasia and adamantinoma may vary considerably.
The interaction of four antimalarials (chloroquine, quinacrine, mefloquine and quinine) with lipid membranes re-formed from lipid extracts of normal human erythrocytes was studied using 2H- and lipid extracts of normal human erythrocytes was studied using 2H- and 31P-nuclear magnetic resonance (NMR). Inclusion of small amounts of chain-perdeuterated dipalmitoylphosphatidylcholine (DPPC) or dipalmitoylphosphatidylethanolamine (DPPE) as an 2H-NMR probe allowed us to study separately the effects of drugs on PC or PE components of the membranes. Only a very small decrease in the order parameters of the DPPE, but not the DPPC probe, was observed in the presence of chloroquine at a molar ratio of 1:5 of drug to lipid. Addition of quinacrine at the same molar ratio resulted in a small but significant decrease in the order parameters of the lipid side chains; identical effects were obtained with DPPC or DPPE perdeuterated probes. The presence of quinacrine did not induce non-bilayer lipid phases. In contrast, mefloquine and quinine produced a significant disordering of the lipid side chains; the effect was considerably larger with the DPPE probe. In addition, both mefloquine and quinine induced non-bilayer phases of the lipids; mefloquine induced formation of hexagonal and micellar lipid conformation, whereas addition of quinine resulted in the formation of lipid micelles only. The lipid polymorphism induced by either of these drugs was more pronounced when the DPPE component was observed, indicating that the non-bilayer phases were enriched in PE. The results suggest the presence of strong interactions between mefloquine and quinine with lipid bilayers, especially with the PE component.(ABSTRACT TRUNCATED AT 250 WORDS)