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Biomedical subjects

H R Song

Publications and source records attributed to H R Song.

At least 19 recordsLinked to original sources
PubMed2001

Impregnation of vancomycin, gentamicin, and cefotaxime in a cement spacer for two-stage cementless reconstruction in infected total hip arthroplasty.

Twenty-two patients with infected total hip arthroplasty were treated with 2-stage arthroplasty, using a cement spacer impregnated with a combination of 3 thermostable antibiotics (vancomycin, gentamicin, and cefotaxime). Initially, implants were removed, and a spacer was inserted. Six to 12 weeks later, the spacer was removed, and the patients underwent reconstruction using cementless components. The patients were followed for an average of 41 months. One patient had a recurrence of infection and was treated with resection arthroplasty. The remaining 21 patients (95%) had no evidence of infection at the final follow-up. We recommend using the combination of these 3 antibiotics in the cement spacer for 2-stage reconstruction in infected hip arthroplasty when the causative organism is not identified in the culture of preoperative aspiration.

Adult↗
PubMed2001

Subcapital fractures associated with extensive osteonecrosis of the femoral head.

The authors reviewed 10 patients with subcapital fractures associated with extensive osteonecrosis of the femoral head and distinguished these fractures from traumatic femoral neck fractures The mean age of the patients was 52 years (range, 36-68 years). Nine patients were younger than 60 years. Eight patients had risk factors for osteonecrosis. Necrosis was extensive and involved nearly the whole femoral head. Fracture occurred at the junction between a necrotic bone and reparative bone and extended downward through the reparative interface to the healthy inferior cortex of the femoral neck. Patients experienced hip pain that was aggravated gradually during a period of 1 to 24 weeks before diagnosis of the fracture. In all patients, the opposite femoral head was involved with osteonecrosis. In two femoral heads, slight collapse or subchondral fracture (crescent sign) also was observed. No patient had a history of precipitating trauma. In patients younger than 60 years with a subcapital fracture, fracture associated with extensive osteonecrosis of the femoral head should be suspected when a history of trauma is not obvious, when the opposite hip shows findings of osteonecrosis, and when the patient has a risk factor of osteonecrosis. In these fractures, osteosynthesis rarely should be considered because of the high failure rate caused by additional progression of extensive osteonecrosis and the probability of nonunion.

Adult↗
PubMed2001

Trochanteric rotational osteotomy for osteonecrosis of the femoral head.

The rate of success of transtrochanteric rotational osteotomy for osteonecrosis of the femoral head may be improved if patients are preselected using MRI. We have used three criteria for selection for osteotomy (i) minor collapse of the infarcted area, loss of congruity or the crescent sign, without narrowing of the joint space or acetabular involvement (ii) patients younger than 55 years and with a painful hip (iii) patients with an intact area constituting an arc of more than 120 degrees between the central vertical line of the femoral head and the posterior or anterior margin of the necrotic portion as seen on a midsagittal MRI. Seventeen patients were selected, with a follow-up of more than 42 months. A bone scan four weeks after operation showed adequate perfusion of the proximal segment in all hips. The hip score of Merle d'Aubigné et al improved from 13.5 points before operation to 17.2 points at the latest follow-up. Further collapse of the femoral head did not occur. The use of MRI instead of plain radiographs for the selection of patients has improved the success rate of transtrochanteric rotational osteotomy.

Adolescent↗
PubMed2000

Purification and characterization of iron superoxide dismutase and copper-zinc superoxide dismutase from Acanthamoeba castellanii.

Two superoxide dismutases (SOD I and SOD II) were purified from Acanthamoeba castellanii and characterized for several biochemical properties. Analysis of the primary structure and inhibition studies revealed that SOD I is iron SOD (Fe-SOD), with a molecular mass of 50 kDa, and SOD II is copper-zinc SOD (Cu,Zn-SOD), with a molecular mass of 38 kDa. Both enzymes have a homodimeric structure consisting of 2 identical subunits, each with a molecular mass of 26 and 19 kDa for SOD I and SOD II, respectively. The isoelectric points of SOD I and SOD II were 6.4 and 3.5, respectively, and there were no isoenzyme forms detected. Both enzymes show a broad optimal pH of 7.0-11.0. Because no differences were observed in the apparent molecular weight of SOD I after addition of the reducing agent 2-mercaptoethanol, the subunits do not appear to be linked covalently by disulfide bonds. However, the subunits of SOD II were covalently linked by intra- and interdisulfide bonds. Western blot analyses showed that the 2 enzymes have different antigenicity. Both enzymes occur as cytoplasmic and detergent-extractable fractions. These enzymes may be potential virulence factors of A. castellanii by acting both as antioxidants and antiinflammatory agents. These enzymes may be attractive targets for chemotherapy and immunodiagnosis of acanthamoebiasis.

Acanthamoeba↗
PubMed1999

Identification of a new polymorphism in the 3'-untranslated region of the human serotonin receptor 2C (5-HT2C) gene.

We identified a polymorphism (2831T > G) in the 3'-untranslated region of 5-HT2C receptor gene, approximately 100 kb from a previously reported coding sequence polymorphism, 796G > C (C23S). Allele frequencies were 0.90 (T) and 0.10 (G) and cosegregation analysis of the alleles at the two loci demonstrated frequencies of 0.82 (GT), 0.08 (CT), 0.10 (GG), and 0 (CC). The increased informativity gained by analysis of both polymorphisms will prove useful for future studies of this gene in X-linked neuropsychiatric disorders.

3' Untranslated Regions↗
PubMed1999

Studies on the sedative and hypnotic effects of oleamide in mice.

The hypnotic and sedative effects of oleamide (CAS 301-02-0) were studied in mice. Intraperitoneal injection of oleamide showed a time-related inhibition of the locomotor activity with the maximum effect appearing 30 min after drug administration. Oleamide, at the dose range of 43.7-700 mg/kg, dose-dependently inhibited the locomotor activity in mice. Oleamide could promote the hypnotic action induced by sodium pentobarbital. The interaction studies showed that oleamide potentiated the inhibitory effect of diazepam (CAS 439-14-5) and antagonized the stimulatory effect of ethanol, methamphetamine, and caffeine, respectively. These results provide further evidence for the hypnotic and sedative effects of oleamide, suggesting a potential therapeutic usefulness of this fatty acid amide.

Animals↗
PubMed1999

Rett syndrome and beyond: recurrent spontaneous and familial MECP2 mutations at CpG hotspots.

Rett syndrome (RTT) is a neurodevelopmental disorder characterized by loss of acquired skills after a period of normal development in infant girls. The responsible gene, encoding methyl-CpG binding protein 2 (MeCP2), was recently discovered. Here we explore the spectrum of phenotypes resulting from MECP2 mutations. Both nonsense (R168X and R255X) and missense (R106W and R306C) mutations have been found, with multiple recurrences. R168X mutations were identified in six unrelated sporadic cases, as well as in two affected sisters and their normal mother. The missense mutations were de novo and affect conserved domains of MeCP2. All of the nucleotide substitutions involve C-->T transitions at CpG hotspots. A single nucleotide deletion, at codon 137, that creates a L138X stop codon within the methyl-binding domain was found in an individual with features of RTT and incontinentia pigmenti. An 806delG deletion causing a V288X stop in the transcription-repression domain was identified in a woman with motor-coordination problems, mild learning disability, and skewed X inactivation; in her sister and daughter, who were affected with classic RTT; and in her hemizygous son, who died from congenital encephalopathy. Thus, some males with RTT-causing MECP2 mutations may survive to birth, and female heterozygotes with favorably skewed X-inactivation patterns may have little or no involvement. Therefore, MECP2 mutations are not limited to RTT and may be implicated in a much broader phenotypic spectrum.

Alleles↗
PubMed1999

Bone marrow edema and associated pain in early stage osteonecrosis of the femoral head: prospective study with serial MR images.

PURPOSE: To determine whether the marrow edema around focal osteonecrosis on magnetic resonance (MR) images is associated with clinical symptoms. MATERIALS AND METHODS: Thirty-three patients with 37 hips showing early stage osteonecrosis of the femoral head were followed up at 3-month intervals with clinical evaluation, conventional radiography, and serial MR imaging. RESULTS: Seven (50%) of 14 symptomatic hips showed marrow edema around focal osteonecrosis on initial MR images, whereas only one (4%) of 23 asymptomatic hips showed edema (P < .01). Six (86%) of seven hips that were moderately to severely painful were associated with surrounding marrow edema. All eight hips showing osteonecrosis with marrow edema at the initial MR examination had joint effusion and exhibited intense radionuclide uptake in the proximal femur, which corresponded to the extent of edema on MR images. In all eight hips, the marrow edema resolved on follow-up MR images, and the pain subsided with the resolution of edema. CONCLUSION: The results of this study suggest that the combination of marrow edema of the proximal femur and focal osteonecrosis of the femoral head are strongly associated with hip pain in early stage osteonecrosis, even prior to collapse. Pain improvement usually parallels the resolution of edema.

Adolescent↗
PubMed1999

Clubfoot analysis with three-dimensional foot models.

The purpose of this study was to develop a method of defining, in mathematical terms, the interpositional relationships of the bones of the hindfoot complex in the idiopathic clubfoot and the neurogenic clubfoot. The neurogenic clubfoot and contralateral normal-appearing foot of a stillborn infant with myelomeningocele, and the normal foot of a 10-year-old were sectioned with a cryomicrotome. Magnetic resonance images (MRIs) of the clubfoot and the normal foot of a 3-month-old boy were obtained. Using a computer program, three-dimensional foot models were generated from the digitized cryomicrotome sections and from the MRIs. The central principal axes were determined for the talus and calcaneus. The long central principal axes of the talus and calcaneus were neutrally rotated with reference to the bimalleolar axis in the idiopathic clubfoot while in the neurogenic clubfoot the long central principal axis of the talus was medially rotated 52 degrees and that of the calcaneus 10 degrees. The talocalcaneal angles defined by the long central principal axes in the superior and medial views were 0 degree and 10 degrees, respectively, in the idiopathic clubfoot, and 42 degrees and 56 degrees, respectively, in the neurogenic clubfoot.

Biomechanical Phenomena↗
PubMed1998

Tibial bone defects treated by internal bone transport using the Ilizarov method.

We reviewed 27 cases of tibial bone defects treated by internal bone transport using the Ilizarov method. The causes of the bone defects were open fractures in 14 segments and infected non-unions in 13. The average length of the defects was 8.3 cm (range, 3-20 cm). There were 21 one-level tibial transports, 3 two-level tibial transports, 1 one-level tibial transport with fibular transport, and 2 fibular transports. At the docking site, 25 segments underwent bone grafting. Eleven of the 25 were Papineau-type open cancellous bone grafts. Acute shortening or docking was performed in 10 segments. Bone union was obtained in every instance. The average time of external fixation was 8 months and the average time to union was 7.1 months. Bone grafting at the docking site is recommended in order to shorten the duration of treatment and to prevent refracture and non-union.

Adolescent↗
PubMed1998

Treatment of antecubital pterygium in the nail-patella syndrome.

Antecubital pterygium is rare in the nail-patella syndrome but common in the multiple pterygium syndrome and aplasia of the trochlea. It is known that there is the rebound phenomenon after treatment of congenital joint contracture. We describe the poor functional results due to rapid recurrence of the flexion contracture treated with the Ilizarov method for an antecubital pterygium in the nail-patella syndrome.

Child↗
PubMed1998

Age-related marrow conversion in the proximal metaphysis of the femur: evaluation with T1-weighted MR imaging.

PURPOSE: To determine the normal chronologic changes in fatty marrow conversion of the proximal femoral metaphysis at magnetic resonance (MR) imaging. MATERIALS AND METHODS: The "marrow conversion index," (signal intensity of the proximal femoral metaphysis divided by signal intensity of the greater trochanter) x 100, was measured in 182 hips of 91 patients who had no evidence of osteonecrosis or diseases involving bone marrow, no history of steroid treatment, and no other risk factors for osteonecrosis. The results were evaluated according to patient age and sex. RESULTS: The index showed a progressive linear increase with age regardless of sex. The index was 65.4% +/- 5.6 (standard deviation) in patients aged 15-19 years and increased monotonously with age to 87.5% +/- 7.0 in patients aged 60-79 years. Simple linear regression of the index according to age group showed that the marrow conversion index is roughly equal to 63 + 4 x Z (p < .001), where Z is 1.5 for patients aged 15-19 years, 2.0 for patients aged 20-29 years, 3.0 for patients aged 30-39 years, 4.0 for patients aged 40-49 years, 5.0 for patients aged 50-59 years, and 6.0 for patients aged 60-79 years. CONCLUSION: There is a linear association of marrow conversion index and age. The estimating equation may provide baseline information for the marrow conversion index.

Adolescent↗
PubMed1997

Gait electromyography in children with myelomeningocele at the sacral level.

OBJECTIVE: Patients with sacral level myelomeningocele can be expected to maintain a high level of ambulatory status long into adulthood. Gait deterioration and knee pain reported in this population may be attributed to compensatory movements and increased recruitment of less affected muscle groups to achieve this desired level of ambulation. The objective of this study was to analyze the effect of the solid ankle-foot-orthoses (AFOs) on the muscular activity of selected muscles during walking. DESIGN: Cohort/outcome. SETTING: Laboratory. PATIENTS: Twenty four patients with sacral level myelomeningocele between 4 to 17 years of age. INTERVENTION: Electromyographic activity of selected muscle groups were studied during barefoot walking and walking with solid AFOs at a self-selected walking velocity. MAIN OUTCOME MEASURES: Timing of electromyographic activity and sagittal plane knee kinematics. Comparison to normal electromyographic patterns and changes between barefoot and AFO walking conditions. RESULTS: With the AFOs there was significantly less prolonged stance phase quadriceps activity compared with barefoot walking, although greater than normal activity persisted. There was no change between conditions for the other monitored muscle groups. All muscles elicited greater duration of activity over the course of the gait cycle. CONCLUSIONS: Our results show that solid AFOs improve the prolonged knee extensor activity evident for barefoot walking. This is clinically relevant to the gait deterioration and knee pain sometimes seen in this patient population. We espouse early and persistent orthotic intervention to reduce compensatory muscular overactivity and maintain gait quality.

Adolescent↗
PubMed1997

Supracondylar osteotomy with Ilizarov fixation for elbow deformities in adults.

Stable fixation after a corrective supracondylar osteotomy in adults is difficult because of the irregularity of the area of bony contact, displacement of the fragments, the predominance of cortical bone, and the need for early mobilisation. We have used the Ilizarov apparatus for fixation in 15 patients who were treated by complex osteotomies with displacement of fragments for cubitus varus or valgus. Most patients with cubitus varus required medial displacement with rotation of the distal fragment. Those with cubitus valgus required lateral shift of the distal fragment to reduce the medial prominence of the elbow that would otherwise result. All osteotomies united within the expected time without loss of correction, despite early mobilisation. Complications related to the fixation were few and had resolved at the long-term follow-up.

Adolescent↗
PubMed1997

Antibiotic-impregnated cement beads in the treatment of chronic osteomyelitis.

Fifty-four patients with chronic osteomyelitis of the long bones were treated at Gyeong-Sang National University Hospital between 1985 and 1993 using the cement bead technique. We studied the results of thirty-one patients who were followed up for 3 years or more. The average duration of follow-up was 4 years and 2 months (range: 3 to 7 years). All of the patients were treated by a two-stage operation; primary saucerization with implantation of antibiotic-impregnated polymethylmethacrylate beads and secondary bone grafts. The most recent follow-up examinations and analyses revealed that 17 patients (55%) were completely free of infection. Ten patients (32%) required repeated procedures of curettage and/or bone grafting. Amputations were performed on 4 patients.

Adolescent↗
PubMed1996

Freeman-Sheldon syndrome (whistling face syndrome) and cranio-vertebral junction malformation producing dysphagia and weight loss.

The whistling face syndrome has been reported, with complications of the respiratory system and feeding problems due to microstomia, since 1938. Dysphagia, however, has not previously been reported as a complication of whistling face syndrome. We report a 13-year-old with the whistling face syndrome and dysphagia of late onset who has the typical whistling face, scoliosis and multiple joint contractures. Dysphagia occurred as a result of compression at the cervicomedullary junction by a cranio-vertebral junction malformation and impingement by the tip of the odontoid process. This child had undergone multiple surgical procedures for cleft palate, clubfeet, contractures of the hip and knee and scoliosis. Halo traction and posterior occipital-cervical decompression and fusion successfully treated the dysphagia.

Adolescent↗
PubMed1995

Preventing collapse in early osteonecrosis of the femoral head. A randomised clinical trial of core decompression.

We performed a randomised trial on 37 hips (33 patients) with early-stage osteonecrosis (ON). After the initial clinical evaluation, including plain radiography and MRI, 18 hips were randomly assigned to a core-decompression group and 19 to a conservatively-treated group. All the patients were regularly followed up by clinical evaluation, plain radiography and MRI at intervals of three months. Hip pain was relieved in nine out of ten initially symptomatic hips in the core-decompression group but persisted in three out of four initially painful hips in the conservatively-treated group at the second assessment (p < 0.05). At a minimum follow-up of 24 months, 14 of the 18 core-decompressed hips (78%) and 15 of the 19 non-operated hips (79%) developed collapse of the femoral head. By survival analysis, there was no significant difference in the time to collapse between the two groups (log-rank test p = 0.79). Core decompression may be effective tin symptomatic relief, but is of no greater value than conservative management in preventing collapse in early osteonecrosis of the femoral head.

Adolescent↗