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Biomedical subjects

D H Han

Publications and source records attributed to D H Han.

At least 55 records · Page 3Linked to original sources
PubMed1997

Insulin resistance of muscle glucose transport in rats fed a high-fat diet: a reevaluation.

Rats fed a high-fat diet develop skeletal muscle insulin resistance. There is disagreement regarding whether a decrease in the GLUT4 isoform of the glucose transporter is responsible. We found that feeding rats a high-fat diet that reduced the responsiveness of glucose transport to insulin in skeletal muscles by approximately 25-45% in 4 weeks, had no significant effect on muscle GLUT4 content. There is also controversy regarding whether the contraction/anoxia activated pathway of glucose transport stimulation is affected by fat feeding. We found that stimulation of muscle glucose transport by either swimming, in situ contractions, or anoxia was depressed to a similar extent as insulin responsiveness in high-fat-fed rats. It has been suggested that the muscle insulin resistance caused by a high-fat diet is due to increased fat oxidation and glucose-fatty acid cycle activity. However, we found that insulin-stimulated glucose transport was reduced by approximately 40% when muscles of fat-fed rats were incubated under anoxic conditions under which fatty acid oxidation should not occur. Rats maintained on the high-fat diet up to 32 weeks developed the characteristics of the abdominal obesity syndrome, including insulin resistance, hyperinsulinemia, hyperglycemia, elevated LDL cholesterol and VLDL triglycerides, and marked visceral obesity. We conclude that 1) in rats fed a high-fat diet the muscle insulin resistance is not due to a decrease in total GLUT4 content or to increased fat oxidation, 2) fat feeding also results in resistance of muscle glucose transport to stimulation via the contraction/anoxia pathway, and 3) rats fed a high-fat diet may be a useful model of the abdominal obesity syndrome.

Adipose Tissue↗
PubMed1996

Effects of liming on uptake of lead and cadmium by Raphanus sativa.

Although liming soil to reduce the heavy metal uptake by plants has been recommended generally, there is some disagreement with the practice based on the results of recent studies. Radishes, Raphanus sativa L. var. Paekyong, were grown in greenhouse pots which were filled with soils treated with 1.52 mg kg(-1) Cd and 25.37 mg kg(-1) Pb, respectively and amended with lime at five rates of 0, 0.25, 0.5, 1.0, and 2.0% by dry soil weight. Plants were harvested three times at 25, 50, and 75 days after sowing and the roots and shoots separated. After the plant samples were digested with HNO3-HClO4, Cd was analyzed by flame AAS and Pb by graphite furnace AAS. A large amount of Cd was translocated into the radishes, which accumulated dramatically with time. Compared to Cd, Pb uptake was very low and accumulated slowly. Cd contents were very much higher in the shoots than the roots, but Pb was not significantly different. Liming or increased soil pH decreased Cd uptake markedly with increased lime level; Pb influence was negligible. Yields were decreased with excessive liming, but not by the levels of Cd or Pb added.

Cadmium↗
PubMed1996

Primary central nervous system lymphoma: variety of clinical manifestations and survival.

A retrospective analysis of 23 non-immune compromised patients with primary central nervous system lymphoma (PCNSL) is reported. The patients consist of 14 males and 9 females and the median age is 50 years. Most patients presented with focal neurological deficits or symptoms of increased intracranial pressure (ICP) due to mass effects around the periventricular area. However, there were four cases of diffuse type, one case of intramedullary tumour, and four cases with rapid disease progression. All the patients underwent histological confirmation by craniotomy (16 cases) or stereotactic biopsy (7 cases). The radiation therapy started after histological diagnosis in all and 6 cases received additional chemotherapy. The median survival after diagnosis of overall patients was 23 months. Six patients are in disease free status at a mean of 35 months follow-up. The uni- and multi-variative risk analysis revealed five favourable factors on survival: (1) age less than 60 years (0.05 < p < 0.1); (2)pre-operative Karnofsky performance scale (KPS) > or = 70 (p < 0.05); (3) symptom duration over four weeks (p < 0.05); (4) radiation dosage > or = 5500 cGy (p < 0.05); (5)absence of malignant cells in cerebrospinal fluid (CSF) (p < 0.05). The most frequent site of recurrence was the local area as shown in seven cases out of 11 recurrent cases. But six patients had diffuse recurrence (4 cases), systemic recurrence (2 cases), and drop metastasis (1 case). Although the recurred PCNSL had rapid progression and a grave prognosis, aggressive treatment prolonged the postrecurrence survival time significantly. Our experience suggests that 1) there are various clinical and radiological presentations and progressions of the disease; 2) treatment method should be decided along with the clinical presentation, progression of disease, and prognostic factors; 3) early diagnosis and early detection of recurrence enable the start of definitive treatment when the medical condition is still satisfactory.

Adult↗
PubMed1996

Cocaine and exercise: temporal changes in plasma levels of catecholamines, lactate, glucose, and cocaine.

To determine the combined sympathoadrenal effects of cocaine and exercise in awake animals, rats were assigned to one of four treatment groups: saline-rest (SR), saline-exercise (SE), cocaine-rest (CR), and cocaine-exercise (CE). Venous blood samples from jugular catheters were obtained at -40, 0-4, 7, 10, 13, 16, 19, 26, and 36 min after intravenous injection of cocaine (5 mg/kg) or saline and the simultaneous onset of a 16-min treadmill run (26 m/min, 10% grade). CE increased plasma epinephrine (24.2 nM at 16 min), norepinephrine (28.0 nM at 10 min), and lactate (11.2 mM at 4 min) to levels 2-5 times greater than either treatment (SE and CR) alone (P<0.05) and 11-35 times higher that SR. Blood glucose values were significantly depressed in CE (-33% vs. SE) but increased in CR (+26% vs. SR). Plasma cocaine peaked < 2 min after injection in both CR and CE, and the peak was 69% higher in CE (P<0.05); however, the plasma elimination half-life (12-14 min) was not different. These results indicate that the combined effect of the two sympathoadrenal stimulants, exercise and cocaine, amplify the catecholamine responses to levels far greater than when each stimulant is used alone.

Animals↗
PubMed1996

Central neurocytoma: proliferative potential and biological behavior.

The authors analyzed 13 central neurocytomas diagnosed at Seoul National University Hospital between January 1982 and December 1993 to clarify the proliferative potential and biological behavior of these tumors. The tumor was confined to the lateral and third ventricles in 12 cases and in one case extended from the posterior thalamus to the body and trigone area of the lateral ventricle. In all 13 cases, typical clinical and radiological findings were observed, and histological diagnosis was performed via craniotomy. The diagnosis was made using light microscopic examination, immunohistochemical staining for neuronal markers, and electron microscopic findings of neuronal differentiation. One patient died due to tumor progression with recurrence 26 months after subtotal removal plus radiation therapy. Another patient had a recurrence 18 months after total tumor removal. The remaining 11 patients are free of recurrent tumor after a follow-up period that ranged from 14 to 109 months (median 50 months). To predict the proliferative potential, immunoreactivity to proliferating cell nuclear antigen (PCNA), silver colloid staining for nucleolar organizing regions (AgNORs), and DNA flow cytometry were performed in 10 of the 13 cases. The proportion of PCNA-positive cells was less than 1% in all cases and the AgNORs score ranged from 1.11 to 2.0 (mean 1.67). The DNA flow cytometry revealed diploidy in all cases and the calculated proliferation index ranged from 5.1% to 9.6% (mean 7.8%). The one case of tumor recurrence, in which the authors performed the study of proliferative potential, and another case that demonstrated mild nuclear pleomorphism also showed low percentages of PCNA-positive cells, low AgNORs scores, and diploidy in DNA flow cytometry. It is suggested that most central neurocytomas follow a benign clinical course with low proliferative potential assessed by PCNA, AgNORs, and DNA flow cytometry; however, recurrence is possible within a relatively short time period.

Adolescent↗
PubMed1996

Cerebral sparganosis: clinical manifestations, treatment, and outcome.

Cerebral sparganosis is a rare parasitic disease caused by infestation by the plerocercoid larva of Spirometra mansoni. The authors retrospectively analyzed 17 cases of cerebral sparganosis treated at Seoul National University Hospital between 1986 and 1994. The patients' ages at diagnosis ranged from 6 to 57 years (median 32 years) and the male/female ratio was 13:4. Diagnosis was based on radiological findings, serological test results, operative findings, and histopathological examinations. Characteristic magnetic resonance (MR) findings consisted of widespread white matter degeneration and cortical atrophy, mixed-signal lesion (low in the central and high in the peripheral regions on T2-weighted images) with irregular dense enhancement of central foci and changes in the location and shape of the enhancing lesion in follow-up studies. Ten patients underwent surgical removal of the parasitic lesion, six received medical treatment alone (five with praziquantel and one with antiepileptic drugs), and one underwent insertion of a ventriculoperitoneal shunt and a course of praziquantel. Follow-up periods ranged from 13 to 111 months (mean 49 months). Seven patients who underwent complete removal of the lesion, live worm, or degenerative worm with surrounding granuloma showed a favorable course. Patients who received medical treatment alone or incomplete removal exhibited progression in their neurological deficits and their seizures could not be controlled. Medication with praziquantel seemed to have no killing effect on live worms. The authors conclude that MR imaging is the most valuable modality for the early detection of cerebral sparganosis and that complete surgical removal of granuloma together with worms, whether they are alive or degenerative, is the treatment of choice.

Adolescent↗
PubMed1996

Unilateral fetal mesencephalic grafting in two patients with Parkinson's disease: short-term result after transplantation.

Fundamental pathological and neurochemical changes in Parkinson's disease are loss of midbrain dopamine neurons that innervate the caudate and putamen. In an effort to replenish the striatal dopaminergic innervation, fetal mesencephalic tissue containing dopamine cells was implanted into the unilateral putamen in two patients with severe Parkinson's disease. The tissue was obtained from three fetuses with gestational ages of 7 to 9 weeks. The cell suspension was stereotactically injected into the unilateral putamen using 5 needle trajectories. Postoperative immune suppression was not performed. Clinical improvement appeared after 2 months. Both patients showed improvement according to the Activities of Daily Living Scale during the off and practically-defined off state 9 and 14 months after surgery. The motor scores of the Unified Parkinson's Disease Rating Scale improved during the off and practically-defined off state 9 and 14 months after surgery. Dyskinesia and off state were shorter and less severe than before the transplantation. Although the long-term effects need to be ascertained, our short-term observation in these two patients with unilateral transplantation is encouraging and justifies further research trials in selected patients.

Activities of Daily Living↗
PubMed1995

Infarction of the territory supplied by the contralateral superior cerebellar artery in a case of descending transtentorial herniation.

Infarction of the territory supplied by the contralateral superior cerebellar artery in cases of descending transtentorial herniation has not been reported. The authors experienced a primitive neuroectodermal tumor in a patient whose consciousness deteriorated transiently due to descending transtentorial herniation. On the magnetic resonance imaging taken 8 days after the herniation, lesions thought to be infarction of territories supplied by the ipsilateral posterior cerebral artery and the contralateral superior cerebellar artery were noted. The possible mechanism of this peculiar pattern of infarction is discussed.

Arteries↗
PubMed1995

99mTc-HMPAO labeled leukocyte SPECT in intracranial lesions.

BACKGROUND: Scintigraphy with 111In (indium-111)-oxine or 99mTechnetium-hexamethylpropyleneamine oxime (99mTc-HMPAO) labeled leukocytes has been used to differentiate brain abscess from brain tumor. However, there are false positive or false negative results from planar scintigraphic images. So a more specific and sensitive scintigraphic technique needs to be developed. METHODS: Planar and single photon emission computed tomography (SPECT) images were obtained and reviewed in 14 patients with intracerebral ring-enhancing lesions on computed tomography (CT) or magnetic resonance imaging (MRI). In all patients, diagnosis was confirmed by histopathologic examination. The effect of steroids or antibiotics on scintigraphic finding was examined. RESULTS: Abscess was confirmed in six patients, tumor in six, tuberculoma and cysticercosis in one each, respectively. In all the patients with abscess, SPECT showed increased focal activity irrespective of steroid or antibiotic therapy. Increased radioactivity, which could not be detected on planar images, could be identified in two patients with abscess. In three of the six patients with tumor, radiolabeled leukocytes did not accumulate in the tumor. In the other three patients with tumor, SPECT showed focally increased activity that was less intense than the activity shown in the patients with abscess. CONCLUSIONS: 99mTc-HMPAO labeled leukocyte SPECT is useful for the differential diagnosis of intracerebral ring-enhancing lesions, and the use of steroids or antibiotics does not influence the sensitivity of SPECT. Diagnostic sensitivity of scintigraphy with labeled leukocytes could be improved by SPECT in addition to planar image.

Adult↗
PubMed1995

Maternal and fetal toxicity of methylmercuric chloride administered to pregnant Fischer 344 rats.

Various doses of methylmercuric chloride (MMC) were administered orally to pregnant Fischer 344 rats on d 7 of gestation. On d 20 of gestation the dams were laparotomized under ether anesthesia, and the fetuses were removed. Maternal body weights were decreased for 2 d and 6 d in rats given 10 and 20 mg/kg MMC, and were continuously decreased for those given 30 mg/kg MMC. Maternal weight gain of each group was decreased to 86.2%, 78.9%, and 61.9% of control group on d 20 of gestation. The reduction of litter weight was greatly enhanced with increasing MMC doses, presumably due to postimplantation loss, which was already increased at high treatment levels. The LD50 of MMC for fetuses was determined to be 16.5 mg/kg. Mercury content in maternal organs was highest in kidney, followed by blood, spleen, liver, and brain, while in fetal organs it was highest in liver. Fetal liver and brain contained more mercury than maternal liver and brain. However, fetal kidney retained less mercury than maternal kidney. Fetal ossification center was not completely formed in sternebrae, particularly in fifth and second bones, pelvic bones, and pectoral phalanges of fetuses in rats treated with 30 mg/kg MMC. The ossified lengths of skeletal bone stained with alizarin red S were developed least in fifth sternebrae, metacarpals in the pectoral girdle, and ischium in the pelvic girdle, and were severely retarded in development as position of the ribs goes from the sixth bone (center) to the first and 13th bone (each edge). These results indicate that MMC is embryotoxic in Fischer 344 rats.

Administration, Oral↗
PubMed1995

Cocaine alters myosin isoform expression in the rat soleus.

The purpose of this study was to determine whether chronic cocaine administration alters the expression of myosin isoforms in the rat soleus. Forty-five adult Sprague-Dawley rats were divided into three groups: chronic cocaine (n = 15), 12.5 mg/kg cocaine-HCl injected intraperitoneally twice daily for 14 days and one injection of cocaine (12.5 mg/kg ip) on day 15; acute cocaine (n = 15), saline injections twice daily for 14 days and one injection of cocaine (12.5 mg/kg ip) on day 15; and chronic saline (n = 15), saline injections twice daily for 14 days and one saline injection on day 15. Myosin isoform content of the soleus (native and heavy chains) was identified by electrophoresis. The solei samples from the chronic saline and acute cocaine animals contained slow myosin only. However, solei samples from the chronic cocaine group contained slow myosin and two to three other myosin isoforms and the associated heavy chains IIa and IIx. Therefore, chronic cocaine administration causes in the rat soleus a shift in myosin expression from slow isoforms to fast isoforms.

Animals↗
PubMed1995

Mycobacterium tuberculosis infection in an orangutan (Pongo pygmaeus).

A respiratory disorder was noted in a 5-year-old female orangutan kept in the Yongin Farmland. Radiographically, multiple radiodense foci ranging from 2 to 6 mm diameter were seen throughout the lung lobes. Grossly, the thoracic cavity revealed a firm texture and grayish-pink discoloration of the left apical lung lobe. Histopathologically, multifocal areas of granulomatous pneumonia present the right and left apical lung lobes. Both primers from IS1081 and IS6110 targeting 196 bp and 245 bp respectively were used in polymerase chain reaction, Mycobacterium tuberculosis was isolated from liver and confirmed by polymerase chain reaction.

Animals↗
PubMed1995

Cocaine and exercise: physiological responses of cocaine-conditioned rats.

To compare the physiological response to a cocaine-exercise challenge in cocaine-conditioned animals with that of acute-cocaine animals, rats were injected i.p. with either cocaine (20 mg.kg-1) or saline, twice daily for 14 consecutive days. On the 15th day (test day) cocaine-conditioned rats received an i.v. injection of cocaine (5 mg.kg-1) (chronic group). One-half of the chronic saline rats also received the cocaine injection (acute group), while the other half received saline (saline group). Immediately after injection, all rats were either rested or exercised (22 m.min-1, 10% grade) for 30 min. For most parameters there was no difference between the responses of the chronic and acute cocaine groups at rest or to the cocaine-exercise challenge. During exercise, both cocaine groups had similarly higher lactate values than the saline animals (P < 0.05). Both groups had similarly greater reductions in glycogen content of the white and red vastus muscles than occurred in the saline group; and both groups had similar increases in corticosterone. In contrast, cocaine-conditioned animals had a greater rise in norepinephrine (P < 0.059) and epinephrine (P < 0.001) in response to cocaine-exercise than did the acute group. The mechanism responsible for the exaggerated catecholamine response in the chronic cocaine animals is unknown.

Adaptation, Physiological↗
PubMed1994

Aneurysm at the origin of accessory middle cerebral artery associated with middle cerebral artery aplasia: case report.

A case of ruptured aneurysm at the origin of accessory middle cerebral artery associated with ipsilateral middle cerebral artery aplasia is reported. The angiograms did not show a middle cerebral artery shadow on the lesion side. Instead, the accessory middle cerebral artery ran toward the Sylvian fissure and supplied the middle cerebral artery territory along with multiple hypertrophied perforating branches. The operative findings confirmed that the cord-like, rudimentary middle cerebral artery had no internal blood flow. The effect of these combined anomalies on the hemodynamic equilibrium between the arteries of the same embryologic trees and the genesis of aneurysm is worthy of notice.

Adult↗
PubMed1994

Traumatic pseudoaneurysm of the intracavernous ICA presenting with massive epistaxis: imaging diagnosis and endovascular treatment.

Traumatic pseudoaneurysm of the intracavernous internal carotid artery (ICA) is a very rare cause of epistaxis but is a life-threatening clinical situation when left untreated. The authors have experienced four cases of traumatic pseudoaneurysm involving the intracavernous ICA. Delayed massive epistaxes developed 1 to 8 months after trauma and initial transient epistaxis in all four patients. Three of the cases were successfully managed by the detachable balloon occlusion (DBO) of the ICA along with the aneurysm openings. In one case, a large pseudoaneurysm destroying a large area of the central skull base with peripheral blood clot was demonstrated on computed tomography, magnetic resonance imaging, and angiography; this patient died due to massive epistaxis before the trial of DBO. Imaging findings of pseudoaneurysms involving the intracavernous ICA in the four cases are described, and the role of endovascular treatment is discussed.

Accidental Falls↗
PubMed1994

Treatment outcome and prognostic factors of medulloblastoma.

Medulloblastoma, once a tumor with a dismal prognosis, is one of the most common primary brain tumors of childhood. As the methods of treatment have been continuously refined, the outcome has improved remarkably during the last few decades. The outcome of 78 medulloblastoma patients, which were managed from 1972 to 1992 at the Department of Neurosurgery of Seoul National University Hospital, were analyzed to calculate the 3-year and 5-year survival rates (3yS and 5yS). Of those, 52 cases which were treated after July 1982 were studied 1) to calculate the 3yS and 5yS, 2) to figure out the prognostic factors of survival, and 3) to investigate the role of adjuvant chemotherapy ('8-drugs-in-a-day' protocol: CCNU, cisplatin, vincristine, hydroxyurea, procarbazine, cytosine arabinoside, methylprednisolone and cyclophosphamide). The 3yS and 5yS of the 78 patients were 57.4% and 47.3%, respectively. Of the 52 patients treated after July 1982, the 3yS and 5yS were 67.8% and 64.1%, respectively. The latest recurrence was at 56 months after surgery. All the recurrences were within the risk period of Collins' rule. Of the prognostic factors studied by univariate analysis (age, sex, Chang's classification T- and M-stages, extent of surgical removal, and chemotherapy), Chang's classification M-stage and sex were the statistically significant factors (p = 0.028 and 0.024 respectively). On multivariate analysis, only the M-stage was statistically significant (p = 0.004). Adjuvant chemotherapy had different influences in different patient groups. Only in the 'poor risk' group, did adjuvant chemotherapy have a strong tendency to better outcome (p = 0.069). Further data collection and analysis will lead to better treatment modalities and better outcome for this most common primary malignant brain tumor in childhood.

Adolescent↗