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Biomedical subjects

B K Han

Publications and source records attributed to B K Han.

At least 19 recordsLinked to original sources
PubMed1993

Mitochondrial DNA polymorphism in Jindo dogs.

Mitochondrial DNA (mtDNA) polymorphism was studied in 21 Jindo dogs inhabiting Jin Island off the Korean peninsula. The polymorphism was analyzed with 10 restriction endonucleases that recognize six base pairs. The sizes of the mtDNA fragments produced by digestion using each endonucleases were separated by agarose gel electrophoresis, and the polymorphisms were detected with Japanese mongrel dog mtDNA as a probe. The mtDNA polymorphism in Jindo dogs was observed with four restriction endonucleases, Apa I, EcoR V, Hinc II, and Sty I. However, no polymorphism was detected with BamH I, Bgl II, EcoR I, Hind III, Pst I, or Xba I. The observed restriction endonuclease morphs were classified into 4 types of distinct cleavage patterns. The average number of nucleotide substitutions per nucleotide site in Jindodogs was estimated to be 0.0086. By UPG phylogenetic analysis, the 4 mtDNA types showed only one cluster. This suggests that Jindo dogs have not diverged from the other cluster up to the present and the species is considerably pure.

Animals↗
PubMed1990

Reversal sign on CT: effect of anoxic/ischemic cerebral injury in children.

A retrospective study was performed to determine the clinical and pathologic features, etiology, and outcome of children with the reversal sign. The reversal sign, a striking CT finding, probably represents a diffuse, anoxic/ischemic cerebral injury. CT features of the reversal sign are diffusely decreased density of cerebral cortical gray and white matter with a decreased or lost gray/white matter interface, or reversal of the gray/white matter densities and relatively increased density of the thalami, brainstem, and cerebellum. Twenty children with the reversal sign were retrospectively analyzed. We divided the patients into three groups: (1) acute reversal, (2) intermediate group, and (3) chronic reversal. There were nine cases of trauma (seven of child abuse); nine hypoxia/anoxia incidents (birth asphyxia, drowning, status epilepticus); one bacterial meningitis; and one degenerative encephalitis. All acute- and intermediate-group patients had respiratory problems requiring ventilator support and intensive care. In five of seven patients who died, autopsy findings were consistent with anoxic/ischemic encephalopathy. Surviving patients have profound neurologic deficits with severe developmental delay. The CT reversal sign carries a poor prognosis and indicates irreversible brain damage.

Brain Edema↗
PubMed1989

Normal thymus in infancy: sonographic characteristics.

A prospective sonographic study of the normal thymus in 56 infants was performed to determine the shape, extent, and echogenicity of normal thymic tissue. The thymus had either a triangular or teardrop shape on longitudinal scans and a trapezoidal or bilobate shape on transverse scans. Typically, the thymus was located anterior to the great vessels and extended down to the upper portion of the heart (in one infant, to the diaphragm). It extended up into the lower cervical area in five infants. The great vessels--including the superior vena cava, aorta, and the pulmonary artery--were well imaged through the thymus. In six infants the thymus encircled the left innominate vein. The echogenicity of the thymus was homogeneous, similar to that of the liver and spleen. The intensity of thymic echogenicity was less than that of the liver, spleen, and thyroid gland. This study demonstrates that the thymus has a characteristic sonographic appearance and can be easily identified.

Child, Preschool↗
PubMed1989

Very-low-birth-weight, preterm infants with or without intracranial hemorrhage. Neurologic, cognitive and cranial MRI correlations at 4-8-year follow-up.

Fourteen very-low-birth-weight (VLBW) preterm infants with and without intracranial hemorrhage (ICH) were prospectively followed from birth to 4 to 8 years for the purpose of determining neurologic and cognitive sequelae associated with ICH severity and to correlate outcomes with brain morphology as determined by Magnetic Resonance Imaging (MRI). Intracranial hemorrhage was documented by cranial ultrasonography performed in early life. Follow-up assessments included neurologic and psychometric examinations and cranial MRI scans. Of six children with no ICH, five had normal results on all three follow-up measures. Three children with Grade I-II ICH had mild to moderate neurologic and cognitive sequelae with focal white matter MRI abnormalities. Five children with Grade III-IV ICH had severe neurologic, cognitive, and MRI deficits, including MRI regional and diffuse white matter abnormalities and/or cortical atrophy. Focal and diffuse neurologic deficits correlated with the extent of MRI morphologic abnormalities. Results of this study indicate that ICH severity correlated with outcomes in children at follow-up; the more severe the ICH, the more adverse the neurologic, cognitive, and MRI results. MRI white matter abnormalities were present in all children with any degree ICH, while ventriculomegaly was seen only in severe ICH (Grade III-IV ICH). Neurologic deficits correlated with MRI structural abnormalities.

Brain↗
PubMed1989

Nuclear cystography and renal sonography: findings in girls with urinary tract infection.

This retrospective study documents the findings on nuclear cystography and renal sonography of 455 girls who had urologic imaging for a proved urinary tract infection (UTI). Nuclear cystograms were normal in 313 (69%) of 455 patients. Vesicoureteral reflux was seen in 142 patients (31%): six with grade I, 90 with grade II, 43 with grade III, and three with grade IV. Twelve percent of patients with vesicoureteral reflux had renal parenchymal scars. Increasing grades of reflux were associated with an increase in the severity and number of parenchymal scars. Normal renal sonograms were seen in 83% of patients. Abnormalities noted on sonograms included parenchymal scarring in 31 (7%) of the 455 patients, anomalies in 19 patients (4%), mild to moderate dilatation of the renal pelvis and or ureters in 45 patients (10%), and bladder wall thickening in 45 patients (10%).

Adolescent↗
PubMed1989

Brain abnormalities in infants on extracorporeal membrane oxygenation: sonographic and CT findings.

The findings of cranial sonography performed before and during extracorporeal membrane oxygenation (ECMO) in 50 near-term infants and CT findings after ECMO in 18 of those patients are reported. Hemorrhage is uncommon in patients being considered for ECMO: subependymal hemorrhage was seen in one case and subependymal cyst possibly due to in utero hemorrhage was seen in five cases. Hypoxic ischemic ischemic injury is more common: severe cerebral edema was seen in two cases, occipital hemorrhagic infarct in one case, and mild cerebral edema in 17 cases. During ECMO, sonograms showed that the hemorrhage in patients with small subependymal hemorrhage or cyst before ECMO did not extend while on ECMO. Typical germinal matrix/intraventricular hemorrhage was seen uncommonly (three cases). Unusual parenchymal hemorrhage did occur. Hypoxic ischemic brain injury was more common: parenchymal hemorrhage was seen in three cases, severe cerebral edema in three cases, and infarction in three cases. Hypoxic ischemic brain injury probably occurs before ECMO, with a delay in visualization. CT after ECMO detected additional abnormalities, particularly peripheral areas of hemorrhage and infarction not visible on sonograms, and is now being performed on all patients. More emphasis should be placed on better screening of infants being considered for ECMO treatment to identify irreversible anoxic brain injury, not just hemorrhage.

Brain Diseases↗
PubMed1988

Bony inlet stenosis as a cause of nasal airway obstruction.

Two cases of congenital bony stenosis of the nasal piriform aperture (anterior nares) are presented. Both patients experienced episodes of respiratory distress and clinical symptoms similar to those seen in patients with posterior choanal atresia. The underlying anatomic abnormalities in congenital bony inlet stenosis are quite different from those in choanal atresia and require different surgical approaches for correction. Computed tomography demonstrates in detail the underlying anatomic abnormality and allows differentiation of bony inlet stenosis from choanal atresia.

Choanal Atresia↗
PubMed1988

Sonographic findings in infants with macrocrania.

This study compares the sonographic and CT findings in a group of infants with macrocrania and correlates those findings with neurologic outcome to determine the diagnostic accuracy and prognostic value of sonography. Sonographic findings in 255 infants with macrocrania are described. Of the 195 term infants examined, 130 had normal sonograms, 11 (5.6%) had significant abnormalities, and 54 had increased intra- and/or extraaxial fluid spaces. Of the 60 former preterm infants, 33 had normal sonograms, four (6.7%) had significant abnormalities, and 23 had increased fluid spaces or small resolving germinal matrix hemorrhages. The patients with significant abnormalities usually had head circumferences greater than the 95th percentile and had neurologic abnormalities. There was good correlation between sonography and CT in 30 of the 36 patients evaluated by both. In six there was mild discrepancy in the volume of the extraaxial fluid. No significant abnormality was missed by sonography. CT did not contribute any additional information. Neurologic follow-up was available for 202 patients. Nineteen percent of the term infants and 24% of the former preterm infants were abnormal on neurologic follow-up. Most patients with normal sonograms were normal on follow-up. Twelve of the term and four of the preterm infants with normal sonograms were developmentally delayed on follow-up. Increased CSF in the ventricles and/or extraaxial spaces was a common abnormality, but it usually is associated with a normal neurologic outcome and represents "benign macrocrania." We conclude that an infant with an enlarged or enlarging head should have a neurologic examination and head circumference measurement. If the patient has a head circumference greater than the 95th percentile, particularly if there are abnormal neurologic findings, further evaluation is indicated. Sonography is the initial procedure recommended since it accurately evaluates ventricular size, extraaxial fluid, and congenital malformations. If sonography is normal or shows mildly increased fluid spaces, then follow-up head circumference measurement and clinical evaluation will probably suffice. CT is indicated if there is a significant abnormality on sonography that requires further clarification.

Brain↗
PubMed1986

Multiple hamartomas associated with intracranial malformation.

We examined a newborn infant with multiple hamartomas, including an epidermal nevus syndrome and a giant pigmented congenital nevocellular nevus, associated with other structural developmental abnormalities such as nevus flammeus, vascular malformation, cutis aplasia congenita of the scalp, cartilage hamartoma, and a lipodermoid of the conjunctiva. This child had a significant brain malformation, diagnosed by sonography and computerized tomography, consisting of a significant enlargement of the left hemisphere not associated with asymmetry of the skull or facial bones. We suggest a careful investigation of the intracranial structures by computerized tomography and/or ultrasonography in case of either extensive linear nevus sebaceous sequence and/or giant pigmented nevocellular nevus.

Adult↗
PubMed1986

Postseptal cellulitis: CT in diagnosis and management.

Thirteen orbital computed tomographic (CT) scans were obtained in 12 patients with postseptal (orbital) cellulitis. Sinus radiographs, which were also obtained, were not helpful in diagnosis or management. The location and extent of the inflammatory process was accurately demonstrated with axial CT scans in all cases. A protocol using CT in the management of postseptal cellulitis is proposed.

Adolescent↗
PubMed1986

Sonography of neck masses in children.

The sonograms and medical records of 49 patients were reviewed to determine if there is a characteristic sonographic appearance for certain neck masses. Neck masses included: inflammatory masses (12), noninflammatory masses (23), and thyroid masses (14). Four entities including thyroglossal duct cyst, fibromatosis colli, cystic hygroma, and multiple lymphadenopathy showed characteristic sonographic appearance. Thyroglossal duct cysts were seen as midline or slightly off midline cystic masses. A sinus tract extending superiorly was nicely demonstrated in one patient. The mass in fibromatosis colli (neonatal torticollis) appeared as a well defined mass clearly within the sternocleidomastoid muscle, uniformly echogenic, but less echogenic than the normal surrounding muscle, without good through-transmission. A cystic or primarily cystic mass with linear septations was the characteristic finding of the cystic hygroma. Multiple lymphadenopathy demonstrated multiple discrete, oval, relatively hypoechoic masses along the cervical lymphatic chain. The sonographic appearance of inflammatory masses was variable, being either inhomogeneously echogenic or of mixed echogenicity. Hemangiomas were either echogenic with cystic vascular spaces or linear septations or relatively homogeneously echogenic. Intrinsic thyroid masses could be distinguished from extrinsic masses in most cases. The demonstration of calcification in a mass was useful in narrowing the differential diagnosis. Although it is not a specific finding, the presence of calcification highly suggests a neoplastic lesion, particularly neuroblastoma or teratoma. Not only can the location, extent, and internal characteristics of a mass be determined, but in certain entities, the sonographic appearance is characteristic and an accurate diagnosis can be made.

Adolescent↗