Biomedical subjects

Y J Lim

Publications and source records attributed to Y J Lim.

At least 55 records · Page 3Linked to original sources

PubMed1996

Two cases of Gamma Knife radiosurgery for low-grade optic chiasm glioma.

The effect of radiosurgery on optic gliomas is uncertain. We report two cases of low-grade glioma of the optic nerve and chiasm treated by transcranial subtotal removal and Gamma Knife radiosurgery. The first case was a 2-year-old boy, admitted with visual disturbance and nystagmus. Histopathological examination showed a pilocytic astrocytoma. The tumor volume was 14.4 cm3. Dose planning was performed using axial and coronal T1-weighted enhanced images. The marginal dose was 12 Gy at the 40% isodose line. The dose to the optic apparatus was less than 9 Gy. The second case was a 47-year-old woman, admitted to our hospital with headache and visual disturbance. The histopathological findings showed a fibrillary astrocytoma. The tumor volume was 12.3 cm3. The marginal dose was 14.4 Gy at the 40% isodose curve. The follow-up periods for the two cases were 24 and 43 months, respectively. In both cases the most recent follow-up magnetic resonance scan showed a marked decrease in tumor size, and visual symptoms were improved. No postradiosurgical complications have developed to date. Gamma Knife radiosurgery could be an effective adjuvant therapy for low-grade optic glioma. However, long-term follow-up is required for further evaluation of the efficacy and potential side effects.

Child, Preschool↗

PubMed1996

Gamma knife radiosurgery in 11 hemangioblastomas.

One suprasellar, one mesencephalic, and nine cerebellar hemangioblastomas were treated with the gamma knife in 10 patients (median age 48 years) in Stockholm between 1978 and 1993. Four patients had von Hippel-Lindau disease, a dominant inherited trait predisposing to multiple hemangioblastomas. Six hemangioblastomas were treated with radiotherapy at a median margin dose of 25 Gy (20-35 Gy) before 1990 and the next five with a median of 10 Gy (5-19 Gy). Computerized tomography or magnetic resonance images were available for 10 of the 11 hemangioblastomas at a median follow-up time of 26 months (4-68 months) after radiosurgery. The solid part of six hemangioblastomas shrank in a median of 30 months, whereas four hemangioblastomas were unchanged at a median of 14 months. Five hemangioblastomas had an adjoining cyst and three of these cysts had to be evacuated after radiosurgery. One solitary hemangioblastoma later developed a de novo cyst that also needed evacuation. One patient with two cerebellar hemangioblastomas (margin dose 25 Gy each) developed edema at 6 months and required a shunt and prolonged corticosteroid treatment. The combined follow-up data of the 23 hemangioblastomas in 15 patients from previous literature and the present series indicate that, first, a solitary small- or medium-sized hemangioblastoma usually shrinks or stops growing after radiosurgery. The recommended margin dose is 10 to 15 Gy. Second, the adjoining cyst often does not respond to radiosurgery but requires later, sometimes repeated evacuation.

Adult↗

PubMed1996

Biochemical and molecular characterization of a strain KA/S2 of Acanthamoeba castellanii isolated from Korean soil.

A strain, KA/S2, isolated from Korean soil and morphologically assigned to Acanthamoeba castellanii, was characterized by isoenzyme analysis, and total proteins profile, and mitochondrial (Mt) DNA restriction fragment length polymorphism (RFLP), and compared with four reference strains assigned to the species (the authenitic Castellani, Neff, Ma, and Chang strains). It was found that four isoenzyme, total proteins, and Mt DNA RFLP patterns by eight restriction endonucleases of the strain KA/S2 were identical with those of the Neff strain, isolated from soil of California, USA. The Chang strain was unique in its morphology and total protein patterns. Interstrain polymorphisms of isoenzyme profiles and Mt DNA RFLP patterns were observed among the Castellani, Neff, Ma, and Chang strains. Mt DNA RFLP was confirmed to be highly appropriate for the strain characterization and identification of Acanthamoeba spp.

Acanthamoeba↗

PubMed1995

Well-differentiated, low-grade osteosarcoma of the clivus.

A case of well-differentiated osteosarcoma of the sphenoid bone was reported. The pathological differentiation of this rare entity from fibrous dysplasia, the radiographic appearance, and the differential diagnosis were discussed.

Diagnosis, Differential↗

PubMed1995

Growth hormone treatment of short Chinese children with beta-thalassaemia major without GH deficiency.

OBJECTIVE: Despite regular transfusion and desferrioxamine treatment, growth failure is commonly seen in adolescent children with beta-thalassaemia major. The growth failure has been thought to be due to GH resistance rather than GH deficiency. We investigated the effect of GH on short non-GH deficient children with beta-thalassaemia. DESIGN: Recombinant human GH was given in a dose of 0.14 IU/kg/day subcutaneously in an open study. PATIENTS: Fifteen prepubertal Chinese children with beta-thalassaemia major (ranging from 7.16 to 14.7 years in age) with height -1.5 SD or more below the population mean for age and a growth velocity of less than 5 cm/year were treated with growth hormone for one year. All children had peak GH response > 15mlU/l to insulin induced hypoglycaemia and normal thyroid function and adrenal reserve. MEASUREMENTS: Anthropometric measurements were performed every 3 months. Morning urine was tested twice weekly for glycosuria. Blood count, renal and liver function tests, fasting blood glucose, IGF-I and fructosamine levels were assessed at entry and every 3 months during treatment. Fasting insulin was measured before and after 3 and 12 months of GH treatment. Skeletal maturity was assessed before and after one year of treatment. RESULTS: Treatment was stopped in two children after 6 months because of poor growth response and noncompliance with treatment and in one child at 9 months because of bone marrow transplantation. In the 13 children, the growth velocity increased from 3.6 +/- 0.7 cm/year to 8 +/- 1.2 cm/year after one year of GH treatment (P < 0.001). IGF-I was low before treatment (10.1 +/- 2.7 nmol/l), rising significantly to 15.8 +/- 4.8, 18.4 +/- 4.6, 19.3 +/- 6.4 and 21.9 +/- 7.5 nmol/l at 3, 6, 9 and 12 months of treatment (P < 0.005). The mean pretreatment bone age in the 13 children was 9.58 +/- 1.41 years and increased to 10.53 +/- 1.43 years after one year of treatment (delta BA/CA 0.95 +/- 0.3 years). None of the patients developed glycosuria or hypertension. There was no significant change in blood count, renal and liver function, thyroid function, fasting blood glucose or insulin concentrations during treatment. CONCLUSION: Growth failure in these children with normal GH reserve and low serum IGF-I concentrations would suggest GH insensitivity. Supraphysiological doses of exogenous GH can cause a significant increase in serum IGF-I levels and a significant improvement in short-term growth of short children with beta-thalassaemia major.

Adolescent↗

PubMed1995

Adrenal 21-hydroxylase deficiency in childhood: 25 years' experience.

OBJECTIVE: To review past and present management of congenital adrenal hyperplasia at a single centre, as a guide to best practice. METHODOLOGY: The records of 89 patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency managed in a children's hospital in Australia over a period of 25 years were reviewed. RESULTS: The diagnosis was made in infancy in 66 patients (37 males and 29 females) and later in 23 (11 males and 12 females). The mean age for genitoplasty in females with ambiguous genitalia was 18 months before 1984 and 3 months thereafter. Significant differences were found between males and females presenting after infancy with regard to virilization, bone age advancement, risk of true precocious puberty and final height. The mean final height standard deviation scores for seven males and seven females treated from infancy were -1.32 and -1.26, respectively. CONCLUSIONS: The results emphasize the importance of early diagnosis and good control in ensuring a good outcome for patients with 21-hydroxylase deficiency.

Adolescent↗

PubMed1995

Urinary 17 alpha-hydroxyprogesterone in management of 21-hydroxylase deficiency.

OBJECTIVES: The study was designed to assess the reliability of measurement of 24-hour urinary 17 alpha-hydroxyprogesterone (17-OHP) by radio-immunoassay (RIA) as an alternative biochemical assessment for monitoring the treatment of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21-OHD) and to assess the need for sample purification by column chromatography to improve assay specificity. METHODOLOGY: Morning serum 17-OHP was measured using RIA and 24-hour urinary pregnanetriol using gas chromatography. Twenty-four-hour urinary 17-OHP was measured in samples from 17 prepubertal patients with CAH due to 21-OHD, and 20 normal prepubertal children as controls. In 24 urine samples, RIA of 17-OHP was performed with and without column chromatography. RESULTS: There was a good correlation between 24-hour urinary 17-OHP and 24-hour urinary pregnanetriol (r = 0.962, P < 0.01) and between 24-hour urinary 17-OHP and morning serum 17-OHP (r = 0.955, P < 0.01). There was no significant difference in the RIA of the urine samples with and without purification by column chromatography. CONCLUSIONS: The measurement of 24-hour urinary 17-OHP is a reliable alternative for the biochemical monitoring of 21-OHD, and RIA specificity is unaffected by omission of column chromatography.

17-alpha-Hydroxyprogesterone↗

PubMed1994

Familial testotoxicosis in a Chinese family.

We report two cases of 'familial testotoxicosis' in a family of Southern Chinese descent. The proband, an 8-year 4-month-old boy and his 35-year-old father both presented with early sexual development. In both cases the testicular volume was only 6 ml despite fully developed secondary sexual characteristics. Both patients had adult testosterone concentrations but a suppressed gonadotrophin response to gonadotrophin-releasing hormone. The suppressed gonadotrophin response to gonadotrophin-releasing hormone in the father suggests that autonomous gonadal production of sex steroid by the testes can persist well into adult life in some patients with familial testotoxicosis.

Adult↗

PubMed1994

Myocardial salvage: its assessment and prediction by the analysis of serial myocardial contrast echocardiograms in patients with acute myocardial infarction.

It has been difficult to assess myocardial salvage in patients with coronary reflow because of the lack of appropriate methods of determining the risk area and assessing effects of coronary reflow in patients, myocardial contrast echocardiography was performed in 28 patients with acute myocardial infarction before reperfusion, immediately after reperfusion, and in the chronic stage with the right and left coronary arterial injection of sonicated ioxaglate. Contrast-deficit and contrast-filled areas before reperfusion were defined as the risk area and noninfarct area, respectively. If the ratio of peak subtracted gray level in the risk area to that in the noninfarct area was < 0.4, the risk area was taken as a contrast defect. Contrast defect was observed even after reperfusion in 8 (29%) patients, and the defect was consistently observed in the chronic stage in all of them. Contrast defect disappeared after reperfusion in the other 20 patients but reappeared in 4 (20%) of them in the chronic stage despite the patent infarct-related vessel. Left ventricular function recovery of the risk area in the chronic stage as assessed with regional wall motion and wall thickness was better in the patients without contrast defect after reperfusion than in patients with persistent or reappeared contrast defect. In conclusion, (1) myocardial salvage is improbable in patients with contrast defect immediately after reperfusion, (2) contrast enhancement immediately after reperfusion does not necessarily imply myocardial salvage in the chronic stage, and (3) myocardial echocardiography in the chronic stage may provide clinically useful information about myocardial salvage in patients with myocardial infarction.

Adult↗

PubMed1994

Screening test for growth hormone deficiency: usefulness of L-dopa-propranolol provocative test.

This is a retrospective review of 185 short children who were tested for growth hormone (GH) secretion using the L-dopa-propranolol provocative test. One hundred and thirty-three children were deemed to have passed the screening test when a GH concentration of greater than 15 miu/L was elicited after stimulation. Fifty-two failed the screening test, of which 33 were diagnosed as having growth hormone deficiency (GHD) when they had inadequate growth hormone response to insulin-induced hypoglycaemia. The other 19 were low-responders since they showed adequate GH response to insulin tolerance test (ITT). The low-responder rate to L-dopa-propranolol provocative test among short children who are not GH deficient was 12.5%. The low cost of L-dopa and propranolol, the simplicity and safety of the test, and the acceptable rate of low-responders make the test an effective screening test for GHD.

Adolescent↗

PubMed1994

High prevalence of Gymnophalloides seoi infection in a village on a southwestern island of the Republic of Korea.

Gymnophalloides seoi (Digenea: Gymnophallidae), a new human intestinal trematode reported from a Korean woman who complained of epigastric discomfort, has been shown to be highly prevalent among the villagers of a southwestern island of the Republic of Korea. For the detection of human infections, fecal examinations were conducted on the inhabitants of a seashore village, where the first patient with a G. seoi infection had resided. Of 98 inhabitants examined, 70 (71.4%) were infected with various intestinal parasites; among them, G. seoi showed the highest rate of egg positivity 48 of 98 (49.0%). Individual worm burdens of G. seoi, as measured by collection of adult flukes after anthelmintic treatment and purgation, ranged from 106 to 26,373 specimens (average per infected case = 3,326). There was no sex-related difference in the prevalence of G. seoi, and the age distribution of the infected cases showed a relatively even pattern. This study confirms that human infection by G. seoi is not an incidental one and provides the first evidence of its high prevalence on this Korean island.

Adolescent↗

PubMed1993

Demonstration of functional border zone with myocardial contrast echocardiography in human hearts. Simultaneous analysis of myocardial perfusion and wall motion abnormalities.

BACKGROUND: Although the presence of a functional border zone (FBZ), defined as the nonischemic but asynergic myocardium adjacent to the ischemic area, has been demonstrated in animal hearts, it is not known whether this zone exists in humans. METHODS AND RESULTS: Myocardial contrast echocardiography (MCE) was performed before and during balloon inflation in the area of coronary stenosis by injecting contrast medium through the guiding catheter in 13 patients with effort angina who underwent successful coronary angioplasty. The area showing MCE defect during balloon inflation was determined with reference to the preangioplasty MCE and was regarded as an ischemic area. The size of the FBZ was assessed by measuring the length of the endocardium that showed asynergy in the echo-enhanced (nonischemic) area. The FBZ measured was 13 +/- 4 mm in the short-axis view (n = 5) and 16 +/- 9 mm in the long-axis view (n = 8). CONCLUSIONS: Nonischemic contractile dysfunction exists even in human hearts. The presence of an FBZ may limit the use of wall motion analysis in assessing the risk or ischemic area in patients with myocardial infarction. MCE appears to be a unique technique for assessing the risk or ischemic area.

Adult↗

PubMed1990

Coronary collaterals assessed with myocardial contrast echocardiography in healed myocardial infarction.

The epicardial coronary collateral vessels are visualized with coronary angiography, but this method does not provide significant information about the myocardial perfusion supplied with the collaterals. In this study, myocardial contrast echocardiography (MCE) was performed to assess the coronary collaterals in 29 patients with old myocardial infarction. MCE was performed by intracoronary injection of 2 ml agitated amidotrizoate sodium meglumine. The peak background-subtracted gray level (PGL) in the infarct area was determined from the digitized echocardiographic images obtained before and after injection into the noninfarct and donor artery. PGL was compared with the 3-point coronary angiographic grades of collaterals. PGL in the infarct area was significantly lower in patients with poor collaterals than in patients with moderate to good collaterals (5 +/- 4 vs 18 +/- 8 U mean +/- standard deviation, p less than 0.01). PGL in the infarct area was less than 10 U in the 3 patients with severe asynergy despite the moderate to good collateral supply, suggesting that activity of the collaterals was not good enough to preserve the wall motion effectively. It is concluded that (1) the degree of MCE enhancement in the infarct area generally corresponded to the collateral grades assessed with coronary angiography, and (2) MCE may provide a measure of the collateral perfusion.

Adult↗

PubMed1989

Visualization of subendocardial myocardial ischemia with myocardial contrast echocardiography in humans.

Previous studies indicate the degree of myocardial echo contrast enhancement may be related to regional myocardial perfusion. In this study, myocardial contrast echocardiography was used to characterize changes in the transmural myocardial blood flow distribution that were provoked by rapid atrial pacing in 11 patients with one-vessel coronary artery disease. Ten patients without coronary artery disease served as controls. Myocardial contrast echocardiography was performed by intracoronary injection of 2 ml hand-agitated amidotrizoate sodium meglumine (Urografin-76) and by imaging a short-axis view of the left ventricle with two-dimensional echocardiography before and during injection of the contrast agent. The two-dimensional echocardiographic images at end diastole, before and after injection of the contrast agent, were digitized off-line into a 512 x 512 pixel matrix with 256 gray levels/pixel to quantify the degree of the enhancement of the peak gray level after injection. Transmural myocardial blood flow distribution was evaluated by measuring the ratio of the enhanced gray level in the endocardial half (endo) to that in the epicardial half (epi) (endo:epi gray level ratio) in the anteroseptal, posterolateral, and inferior segments before and just after rapid atrial pacing in each patient. In patients without coronary artery disease, there were no differences in the endo:epi gray level ratio between any of the three segments both before and after pacing. Mean values of the three segments were 0.95 +/- 0.08 before pacing and 0.90 +/- 0.13 after pacing, respectively. In contrast, in patients with coronary artery disease, the endo:epi gray level ratio for the segment supplied with stenotic coronary artery decreased after pacing (0.40 +/- 0.21 vs. 0.93 +/- 0.18, p less than 0.01), probably reflecting subendocardial myocardial ischemia, whereas that for the segment supplied with nonstenotic coronary artery remained unchanged (0.88 +/- 0.20 vs. 0.99 +/- 0.23, NS). Thus, changes in transmural myocardial blood flow distribution with rapid pacing, which may be due to transient subendocardial ischemia, are visualized with myocardial contrast echocardiography.

Adult↗

PubMed1989

[Evaluation of function of human collateral coronary arteries using myocardial contrast echocardiography].

The morphology of collateral vessels can be imaged by coronary angiography, but no method has been available for evaluating their function. This is a report of the use of regional myocardial perfusion to visualize collateral flow by means of myocardial contrast echocardiography in 28 patients with old myocardial infarction. Myocardial contrast echocardiography was accomplished by the intracoronary injection of two ml agitated amidotrizoate sodium meglumine. Short-axis images of the left ventricle were recorded on video tape. Those images were digitized off-line into a 512 x 512 pixel matrix. Using coronary angiography, the morphology and function of the collateral vessels were evaluated, then classified as poor, moderate or good. Myocardial perfusion was evaluated using the enhanced gray level after contrast injection, and the level was compared with the morphology and degree of collateral development. The enhanced gray level was evaluated arbitrarily as 3 +/- 2 U (mean +/- S.D.) in the "poor" group; 13 +/- 6 U in the "moderate" group; and 20 +/- 11 U in the "good" group (p less than 0.01 vs the "poor" group; NS vs the "moderate" group). Regional myocardial perfusion via the collateral vessels was generally proportional to the morphology. However, there were a few discrepancies between these two parameters.

Aged↗

PubMed1989

[Discrepancies between wall motion abnormalities and regional myocardial perfusion in patients with myocardial infarction: evaluation by myocardial contrast echocardiography].

Regional myocardial perfusions obtained by myocardial contrast echocardiography were compared with wall motion abnormalities evaluated by two-dimensional echocardiography in 26 patients with old myocardial infarction (12 with a QS pattern and 14 with a non-QS pattern on electrocardiograms). Myocardial contrast echocardiography was performed by the intracoronary injection of 2 ml of hand-agitated Urografin-76, and short-axis views of the left ventricle were recorded on VTR. Regional myocardial perfusion was categorized using a three-point scale based on the gray levels, and was compared with wall motion abnormalities of the corresponding region as assessed by two-dimensional echocardiography.

Adult↗

PubMed1989

A quicker simpler method of pre-determination of the length of umbilical artery catheter insertion in Asian babies.

A total of 50 neonates with birth weights varying from 919 gm to 5 kg with acute respiratory distress were studied for umbilical artery catheter placement in the thoracic aorta at T7 to T11 vertebral body level. The length of the catheter to be inserted was by a simple formula ie. for a 1000 gm baby, the length of insertion is 10 cm (delete the 00 from 1000 gm), and add 1 cm for each additional weight group of 250 gm till 2250 gm. Above 2250 gm, the length of insertion is 15 cm for all babies. Considering the 49 babies whose birth weights were more than a kg, 47 babies had catheter tips located at T7 and T11 vertebral body level. This method was thus accurate in 95.9% of babies studied.

Aorta, Thoracic↗

PubMed1988

[Regional myocardial perfusion in ischemic heart disease assessed by myocardial contrast echocardiography].

Myocardial contrast echocardiography is a new cardiovascular imaging technique that can be used to evaluate regional myocardial perfusion. Regional myocardial perfusion was studied in 12 patients with normal coronary arteries, 14 patients with old myocardial infarction, four patients with acute myocardial infarction, and 15 patients with effort angina. Conventional two-dimensional echo imaging was obtained during intracoronary injections of relatively small volumes (2 ml) of agitated Urografin-76. The echo intensities were measured before and after injecting contrast agents and the subtraction images were composed by a high-speed image processor (NEXUS 6400). Clear myocardial images were obtained in 10 of 12 the patients with normal coronary arteries, and they reflected well the epicardial arterial architecture by coronary angiography. In cases of old myocardial infarction, the infarcted areas appeared as contrast defects in seven and as slightly enhanced areas in three of the 10 patients. In cases of acute myocardial infarction, contrast defect areas in the myocardial images were less in two cases of successful early coronary thrombolysis or percutaneous transluminal coronary angioplasty (PTCA). However, contrast defects remained unchanged despite good recanalization in one case of delayed PTCA. In cases of effort angina, anginal attacks were successfully induced by rapid atrial pacing in six of the 15 patients. In four of the six patients, contrast enhancement in myocardial imaging during anginal attack decreased more in the endocardial than in the epicardial myocardium, possibly reflecting subendocardial ischemia. It is concluded that this technique can identify regional myocardial perfusion, which is not revealed by coronary angiography, and it is therefore useful for the clinical analysis of ischemic heart disease.

Angina Pectoris↗