The role of distraction osteogenesis in oral and maxillofacial surgery.
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Humans↗
Biomedical subjects
M Chin
Publications and source records attributed to M Chin.
Effect of valine-depleted total parenteral nutrition on fatty liver development in tumor-bearing rats.
Valine-depleted amino acid imbalance, while having a suppressive effect on tumor growth, may induce fatty liver. We administered valine-depleted total parenteral nutrition (TPN) solution to rats subcutaneously transplanted with ascites containing hepatoma AH-109A and examined the time course of the development of fatty liver. An accumulation of fatty vacuoles was observed in hepatocytes on day 4. To prevent the development of fatty liver in tumor-bearing rats, we administered a small amount of valine in addition to the valine-depleted imbalance solution via the central vein. Such treatment, however, resulted in neither the prevention of fatty liver development nor the suppression of tumor growth. To supply valine to the liver, we administered a low concentration of valine via the portal vein simultaneously with central venous administration of valine-depleted TPN solution. As a result, the peripheral blood valine level of these rats was < 0.5 that of the control group, but the valine in the liver was maintained at the same level as that of the control group, and accumulation of triacylglycerols in the liver was slight. However, the suppressive effect on tumor growth was maintained, as the tumor weight was suppressed to almost the same degree as that of rats administered only the valine-depleted solution.
Amino Acids↗
Distraction osteogenesis and its application to the midface and bony orbit in craniosynostosis syndromes.
The purpose of this study was to demonstrate the potential advantages of applying distraction osteogenesis techniques to the correction of orbital and midfacial hypoplasia in craniosynostosis syndromes. Fifteen children with various craniosynostosis syndromes underwent Le Fort III advancement assisted by gradual distraction utilizing a pair of internal distraction devices custom-fabricated for each child. The surgical procedure consisted of a Le Fort III osteotomy, implantation of internal devices with initiation of distraction intraoperatively, and an accelerated rate of midfacial advancement over the next 3 to 5 days. Activation of the distraction hardware was accomplished by a percutaneous pin, which was removed at the end of the distraction protocol, allowing the internal devices to fixate the fragment for a minimum of 6 months during the period of consolidation. With follow-up ranging between 3 to 38 months, the average orbital and midfacial advancement was 19.7 mm (range, 12.0-30.0 mm). Proptosis was lessened and facial proportions significantly improved in all patients. Serious complications were not encountered. The modified distraction protocol utilized in this group of patients was aimed at addressing the unique requirements of pediatric craniofacial surgery, and resulted in almost twice the amount of correction previously reported for traditional rigid fixation techniques.
Adolescent↗
[Bone marrow relapse in high-risk pediatric patients with acute lymphoblastic leukemia: a comparison of relapse times and initial clinical features of patients on different protocols. Children's Cancer and Leukemia Study group (CCLSG)].
To clarify the efficacy of modern intensive chemotherapy for ALL patients with unfavorable features, we compared the time to failure and initial clinical features of children who relapsed in the bone marrow or combined sites, as documented by early CCLSG studies (H811 and H851; 1981-1987) and later studies (H874 and H/HH911; 1987-1993) concerning high-risk ALL patients. In the later studies patients outcomes with new intensive regimens employing early intensification and reinduction therapy were apparently better than those of patients in the early studies with conventional regimens. When we compared the number of relapsed patients based on duration of first remission, we found that the improved outcomes for patients in the later studies were due to a decrease in the number who relapsed 7-36 months after the start of treatment (intermediate relapse), and that the percentage of those who relapsed within the first 6 months of therapy (early relapse) was higher. Patients with high initial WBC counts tended to relapse much earlier than those with low initial WBC counts. However, in the later studies, patients with high WBC counts often relapsed after the termination of therapy (late relapse). These results suggest that the intensive chemotherapy regimens used in the later studies can prevent the development of drug resistant leukemic clones, except in extremely high-risk patients likely to relapse within the first 6 months of therapy.
Antineoplastic Combined Chemotherapy Protocols↗
[Studies of childhood non-Hodgkin's lymphoma--treatment results with the CCLSG NHL 960 protocol. Children's Cancer and Leukemia Study Group (CCLSG)].
We report here on the preliminary treatment findings of a CCLSG NHL 960 study that was initiated in March 1996. In this study, 37 patients with non-Hodgkin's lymphoma were assigned to 4 different treatment groups according to disease stage and histology: (1) localized disease; (2) advanced disease, lymphoblastic type; (3) advanced disease, large cell type; and (4) advanced disease, Burkitt type. The first three groups received the modified protocols of the NHL 890 study. Groups 1 and 3 received COPADM induction therapy (CPM, VCR, PRD, ADR, and MTX). After achieving remission, Group 1 received only maintenance therapy consisting of alternate administration of 7 drugs, while Group 3 received additional intensification therapy with combination chemotherapy consisting of MTX and Ara-C, followed by a maintenance phase involving the administration of 9 drugs. Group 2 received COPADL induction therapy (CPM, VCR, PRD, ADR, and LASP) and consolidation/intensification therapies followed by a maintenance phase. Group 4 received short-term intensive COPADM polychemotherapy. Twelve patients with localized with localized disease (stage I-II) and 25 patients with advanced disease (stage III-IV) were enrolled in this study. Except for 2 patients in the advanced disease stages who died earlier in the course of the study, all patients remained in remission.
Adolescent↗
Electrophysiological effects of long, linear atrial lesions placed under intracardiac ultrasound guidance.
BACKGROUND: A curative atrial fibrillation procedure will most likely rely on creating transmural linear ablative lesions. However, it is currently unknown whether endocardial radiofrequency lesions can create lines of conduction block. METHODS AND RESULTS: In six pigs, intracardiac echocardiography was used to guide the positioning of multiple coil array catheters to bridge endocardial structures in three right atrial locations: (1) from the crista terminalis to the tricuspid annulus; (2) from the fossa ovalis to the crista terminalis; and (3) from the inferior vena cava to the tricuspid annulus. Once the catheter was positioned, linear lesions were made by radiofrequency energy applied sequentially to each of the four coils. After 15 days, the chest was opened and a 112-electrode epicardial plaque was positioned over the atrial free wall lesion to determine activation patterns. Three lesions were placed in each animal, with a mean procedure time of 47+/-11 minutes. Once adequate contact was determined by intracardiac echocardiography, a single series of radiofrequency application was required to achieve tissue heating (65+/-4 degrees C) with a power of 21+/-10 W. Epicardial mapping demonstrated complete conduction block across the lesions in all animals, with split potentials and disparate activation times (64+/-16 ms) across the lesion. At autopsy, all lesions were discrete, continuous, and without evidence of charring. The lesions were within 0.3+/-0.5 mm of their targeted anatomic locations and measured 21+/-4 mm long and 2.8+/-0.6 mm wide. Histology revealed transmural fibrosis throughout the length of each lesion. CONCLUSIONS: Linear lesions that are electrophysiologically transmural and continuous can be placed in the right atrium of normal pigs. With intracardiac echocardiography, adequate tissue contact over several coil electrodes can be ensured, resulting in short procedure times, efficient energy application, and accurate anatomically linked lesion placement.
Animals↗
Effects of caloric intake on anticancer therapy in rats with valine-depleted amino acid imbalance.
Valine-depleted amino acid imbalance solution markedly inhibits tumor growth but causes fatty liver as a side effect. However, much remains unknown about the mechanism of the development of fatty liver. Valine-depleted amino acid imbalance solution containing various concentrations of calories was administered to tumor-bearing rats for four days by means of total parenteral nutritional methods to investigate the interaction of caloric intake and the development of fatty liver. Compared with the total parenteral nutrition control group the triglyceride content of the liver rose significantly in the group given valine-depleted amino acid imbalance solution with an increase in caloric intake. Plasma total protein and albumin significantly decreased. The very-low-density lipoprotein concentration in serum was also significantly lower than that in the control group. Valine-depleted amino acid imbalance caused hypoproteinemia, suggesting a fall in synthesis of apolipoproteins in the liver indispensable for lipid release. Along with the increase in the total caloric intake, triglyceride synthesis in the liver increased, resulting in augmentation of fatty content of the liver, probably because of the decreased lipid release.
Amino Acids↗
Le Fort III advancement with gradual distraction using internal devices.
The purpose of this report is to demonstrate a practical clinical method for advancement of the midface using a combination of Le Fort III osteotomy and gradual distraction. Use of internal, submergible distraction devices and modification of the Ilizarov distraction protocol are presented. Case reports show the effect of departing from the Ilizarov protocol by eliminating the latency period, initiating distraction intraoperatively, and rapidly distracting the segments postoperatively. A method of controlling fragment distraction rate by regulating pressures within the osteotomy site is described. The design and surgical application of internal distraction devices are shown. Nine patients with midface hypoplasia related to craniofacial anomalies underwent Le Fort III osteotomies assisted by gradual distraction. Ages ranged from 4 to 13 years. Custom internal distraction devices were employed to meet the unique requirements of each patient. Activation of the distraction device was accomplished by a percutaneous pin that remained in place for 3 to 5 days. The rate of transport was determined by regulating the forces within the distraction site. The internal devices remained in place for 6 months for fixation of the transported fragment. Midface advancement, measured as the anterior displacement of the infraorbital rim, ranged from 16 to 30 mm, with a mean of 20 mm. The typical force required to produce incremental movement of the Le Fort III osteotomy was found to be between 7 and 9 kg as transport exceeded 10 mm. Four patients with obstructive sleep apnea prior to surgery had resolution of the disorder. All the midface advancements remained clinically stable. Establishment of osseous continuity was verified by surgical examination in the four patients in whom the distraction devices have been removed. Combining intraoperative advancement of the Le Fort III osteotomy with gradual distraction consistently resulted in larger movements than could be achieved with conventional osteotomies and rigid fixation alone. The pediatric craniofacial skeleton responds differently to distraction than does the orthopedic skeleton. Eliminating the latency period, establishing a substantial bone gap intraoperatively, and rapidly distracting the fragment postoperatively did not adversely affect the osseous union in these patients. The internal, submergible feature of the device design offers advantages in patient acceptance, fixation stability, and wound management. This method of Le Fort III midface advancement has been shown to be clinically practical and effective.
Adolescent↗
Myocardial perfusion imaging with a combined x-ray CT and SPECT system.
UNLABELLED: We evaluated a novel combined x-ray CT and SPECT medical imaging system for quantitative in vivo measurements of 99mTc-sestamibi uptake in an animal model of myocardial perfusion. METHODS: Correlated emission-transmission myocardial images were obtained from 7- to 10-kg pigs. The x-ray CT image was used to generate an object-specific attenuation map that was incorporated into an iterative ML-EM algorithm for reconstruction and attenuation correction of the coregistered SPECT images. The pixel intensities in the SPECT images were calibrated in units of radionuclide concentrations (MBq/g), then compared against in vitro 99mTc activity concentration measured from the excised myocardium. In addition, the coregistered x-ray CT image was used to determine anatomical boundaries for quantitation of myocardial regions with low perfusion. RESULTS: The accuracy of the quantitative measurement of in vivo activity concentration in the porcine myocardium was improved by object-specific attenuation correction. However, an additional correction for partial volume errors was required to retrieve the true activity concentration from the reconstructed SPECT images. CONCLUSION: Accurate absolute SPECT quantitation required object-specific correction for attenuation and partial volume effects. Additional anatomical information from the x-ray CT image was helpful in defining regions of interest for quantitation of the SPECT images.
Algorithms↗
Percutaneous multielectrode endocardial mapping during ventricular tachycardia in the swine model.
BACKGROUND: Identification of critical areas within the ventricular tachycardia circuit is a prerequisite for catheter ablation. Currently, mapping during ventricular tachycardia, usually performed with standard catheters, is difficult and time-consuming and can be used only in patients with hemodynamically stable tachycardia. METHODS AND RESULTS: A total of 43 pigs underwent closed-chest induction of myocardial infarction. A basket-shaped catheter carrying 64 electrodes was deployed in the left ventricle during normal sinus rhythm. Unipolar pacing at 3 mA was successful in 78% of the basket catheter electrodes, demonstrating good electrode-tissue contact. Hemodynamic and echocardiographic measurements did not reveal any significant interference with myocardial or valvular function during or after catheter deployment. One hundred eighteen episodes of monomorphic ventricular tachycardia were induced in 28 pigs through right ventricular stimulation, 81 of which were mapped and analyzed. Ventricular tachycardia mapping was rapid, requiring only several beats and < 10 seconds to complete. Presystolic potentials, a possible target for ablation, were identified in 58% of the tachycardia episodes mapped. Pathological examination revealed only minor valvular and endocardial catheter-induced lesions immediately after mapping and none a month later. CONCLUSIONS: The multielectrode catheter enables rapid and safe percutaneous endocardial mapping of ventricular tachycardia in the swine model. Exploration of the clinical potential of the multielectrode catheter seems warranted.
Animals↗
A quantitative test to estimate neutralizing antibodies to the hepatitis C virus: cytofluorimetric assessment of envelope glycoprotein 2 binding to target cells.
Hepatitis C virus (HCV) is a major cause of chronic hepatitis. The virus does not replicate efficiently in cell cultures, and it is therefore difficult to assess infection-neutralizing antibodies and to evaluate protective immunity in vitro. To study the binding of the HCV envelope to cell-surface receptors, we developed an assay to assess specific binding of recombinant envelope proteins to human cells and neutralization thereof. HCV recombinant envelope proteins expressed in various systems were incubated with human cells, and binding was assessed by flow cytometry using anti-envelope antibodies. Envelope glycoprotein 2 (E2) expressed in mammalian cells, but not in yeast or insect cells, binds human cells with high affinity (Kd approximately 10(-8) M). We then assessed antibodies able to neutralize E2 binding in the sera of both vaccinated and carrier chimpanzees, as well as in the sera of humans infected with various HCV genotypes. Vaccination with recombinant envelope proteins expressed in mammalian cells elicited high titers of neutralizing antibodies that correlated with protection from HCV challenge. HCV infection does not elicit neutralizing antibodies in most chimpanzees and humans, although low titers of neutralizing antibodies were detectable in a minority of infections. The ability to neutralize binding of E2 derived from the HCV-1 genotype was equally distributed among sera from patients infected with HCV genotypes 1, 2, and 3, demonstrating that binding of E2 is partly independent of E2 hypervariable regions. However, a mouse monoclonal antibody raised against the E2 hypervariable region 1 can partially neutralize binding of E2, indicating that at least two neutralizing epitopes, one of which is hypervariable, should exist on the E2 protein. The neutralization-of-binding assay described will be useful to study protective immunity to HCV infection and for vaccine development.
Cell Line↗
Distraction osteogenesis in maxillofacial surgery using internal devices: review of five cases.
PURPOSE: The purpose of this report is to show the feasibility and potential advantages of using internal devices for distraction osteogenesis in the management of maxillofacial skeletal deficiencies. PATIENTS AND METHODS: Distraction osteogenesis was used to correct a variety of maxillofacial skeletal deformities in five patients. One patient underwent bilateral Le Fort III advancement aided by distraction, three patients underwent mandibular ramus lengthening, and one patient underwent segmental alveolar reconstruction by distraction. The devices were activated by either a transcutaneous or transmucosal pin. After achievement of the desired skeletal transport, the activating pins were disengaged and removed from the distraction device. This allowed the distraction device to remain submerged and to stabilize the site of the consolidating bone. RESULTS: All patients achieved lengthening of their jaws. However, premature consolidation was noted in two patients, and one patient had significant relapse. CONCLUSIONS: Development of internal distraction devices is important to address the limitations of currently available biphasic systems. Potential benefits of internal devices include 1) elimination of skin scarring caused by translation of transcutaneous fixation pins, 2) improved patient compliance during the fixation or consolidation phase because there is no external component, and 3) improved stability of the attachment of the device to the bone.
Acrocephalosyndactylia↗
Treatment of aplastic anemia with antithymocyte globulin, cyclosporin A, methylprednisolone, danazol and recombinant human granulocyte-colony stimulating factor.
The main purpose of the present study was to determine the response rate to immunosuppressive therapy combined with recombinant human granulocyte-colony stimulating factor (rhG-CSF) and its efficacy for preventing infections in patients with severe aplastic anemia. The treatments included one course of antithymocyte globulin, cyclosporin A, methylprednisolone, danazole and rhG-CSF. Three patients had very severe aplastic anemia and two had moderate aplastic anemia. One patient relapsed 13 months following the first course of therapy and received a second course. Five patients received six courses of treatment and the response rate at 6 months was 83.3%. All patients achieved an absolute neutrophil count of greater than 1.0 x 10(9)/L within 40 days. All patients with a complete response are transfusion-free and doing well. All five patients are currently alive and have not had any episode of infection for 17-53 months. The results of the study indicate that this therapy may improve the poor prognosis of young patients with severe aplastic anemia. It has a good response rate and induces a rather rapid increase in the neutrophil count, which protects against life-threatening bacterial and fungal infections.
Adolescent↗
Comprehensive treatment of advanced neuroblastoma involving autologous bone marrow transplant.
Encouraging results are reported with high-dose chemotherapy and total body irradiation followed by autologous bone marrow transplantation in the treatment of advanced neuroblastoma. However, relapse remains a significant problem. We used high-dose chemotherapy, surgery, intraoperative radiation and an autologous bone marrow transplant treated in vitro to remove tumor cells followed by 13-cis-retinoic acid to treat 36 children with advanced neuroblastoma. This comprehensive treatment appears to improve the survival rate of patients with advanced neuroblastoma, including those with N-myc amplification and bony involvement. The disease-free survival rate was 66% (95% confidence interval, 49-84%) at 3 years. All patients who received 13-cis-retinoic acid developed cheilitis, but no bone marrow depression occurred in these patients. Five patients developed hemolytic uremic syndrome (HUS) post-transplant. This may have been related to the procedure used for total body irradiation. Patients who had their kidneys shielded during this procedure did not develop this syndrome. Patients who received local irradiation at the primary site showed no evidence of relapse in this region, indicating that such therapy may help to prevent a relapse. These data suggest a high rate of 3 year disease-free survival with this treatment strategy. The nonrandomized nature of the study and use of multiple modalities precludes analysis of the specific contribution of each.
Adrenal Gland Neoplasms↗
Successful autologous bone marrow transplant for relapsed Ki-1 lymphoma.
We report on a 16 year old girl with relapsed Ki-1 lymphoma and a very poor prognosis. The initial manifestation was multiple bone metastases and lymphadenopathy. The patient achieved remission with modified adriamycin, bleomycin, vincristine, daunomycine therapy. However, 14 months after the completion of therapy, relapse occurred in a new cervical lymph node on the left side. After preparation with chemotherapy and total lymphoid irradiation (TLI) the patient underwent autologous bone marrow transplantation (A-BMT). Ki-1 lymphoma shows clinically diverse symptoms, but hematopoietic stem cell transplantation should be performed in relapsed cases. It may be effective to give TLI followed by A-BMT for patients such as ours who have lymph node involvement without bone marrow metastasis.
Adolescent↗
Intraorbital malignant lymphoma presenting with tumor stain on angiography--case report.
A 58-year-old male presented with a 1 month history of left retro-orbital pain and diplopia. Computed tomography demonstrated an isodense intraorbital tumor with slight homogeneous enhancement. Magnetic resonance imaging showed the tumor was isointensity on T1-weighted imaging, slightly high intensity on T2-weighted imaging, and slightly enhanced by gadolinium-diethylenetriaminepenta-acetic acid. Left external carotid angiography showed a tumor stain fed from the branches of the left internal maxillary artery. The tumor was partially removed. The histological diagnosis was malignant lymphoma. Tumor staining is rare in intraorbital malignant lymphoma and is not adequate for differential diagnosis of intraorbital tumors, so biopsy is essential.
Carotid Artery, External↗
[Studies concerning the pathogenesis of trigeminal neuralgia caused by cerebellopontine angle tumors].
It has been well recognized that neurovascular compression can elicit trigeminal neuralgia (TN) and microvascular decompression surgery has become popular as a radical treatment of this clinical symptom. Cerebellopontine (C-P) angle tumors, however, as well known, can also cause TN. Four hundred fifty six patients with TN underwent posterior fossa exploration between 1984 and 1992 in our clinic, and among them, 45 (9.9%) patients harbored C-P angle tumors which were causative of TN. They included 22 epidermoids, 18 meningiomas and 5 neurinomas. The patient population consisted of 35 women and 10 men, ranging in age from 28 to 73 years, with a mean age of 51.7 years. The mean age of the patients of TN with tumors is considerably lower than that of neurovascular compression patients (61.0 years), particularly in cases of neurinomas (44.4 years) and epidermoids (48.0 years) (p < 0.01). Such difference in ages at the onset of symptom may be explained by the fact that the tumor growth in the C-P angle develops earlier than changes of the vasculature of the vertebrobasilar artery system by aging. Anatomical relationships between the 5th cranial nerve and offending arteries or tumors verified at surgery are as follows; Type A: The nerve is totally encased by the tumor. Type B: The axis of the nerve is distorted by the tumor. Type C: The nerve is shifted by the tumor and is compressed by the artery contralaterally. Type D: The nerve is compressed by the artery which was displaced by the tumor.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗