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Biomedical subjects

H K Lim

Publications and source records attributed to H K Lim.

At least 73 records · Page 4Linked to original sources
PubMed1998

A case of arteriovenous type cardiac hemangioma.

Cardiac hemangiomas are rare primary tumors of the heart and constitute only 2.8% of primary cardiac tumors. They are classified into capillary, cavernous, epitheloid and arteriovenous type and the last one is the most uncommon type. We experienced a case of cardiac hemangioma which was diagnosed as arteriovenous type for the first time in Korea in the literature. The patient was a 54-year-old woman who presented with palpitation and anterior chest pain. The diagnosis was based upon coronary angiography which showed two tumor blushings located in the interatrial and interventricular septum with venous drainage to the coronary sinus and right atrium. Associated atrial fibrillation with rapid ventricular response was controlled with digitalis.

Atrial Fibrillation↗
PubMed1997

Differential diagnosis of cervical lymphadenopathy: usefulness of color Doppler sonography.

OBJECTIVE: The purpose of this study was to evaluate the usefulness of color Doppler sonography in differentiating benign from malignant cervical lymphadenopathy. MATERIALS AND METHODS: We used color Doppler sonography to evaluate 117 lymph nodes in 105 patients. The patients were pathologically and clinically confirmed to have benign reactive lymphadenitis (n = 28), tuberculosis (n = 17), lymphoma (n = 14), and metastasis (n = 46). The patterns of hilar vascularity, central nodal vascularity, and peripheral vascularity were assessed. The highest resistive index and pulsatility index in 116 lymph nodes were measured from spectral waveforms. Histologic findings of nodal vessels were analyzed in 14 nodes and compared with findings on color Doppler sonograms. RESULTS: Thirty-two (94%) of 34 nodes with benign reactive disease showed normal patterns of nodal vascularity; central hilar vascularity, radial symmetric central vascularity, and no peripheral vascularity. At least one of six abnormal patterns of vascularity (eccentric or absent hilar vascularity; deformed radial, aberrant multifocal, or absent central vascularity; and peripheral vascularity) was observed in 98% (65/66) of nodes with malignant disease and in all tuberculous nodes. We established cutoff values of 0.8 for the resistive index and 1.5 for the pulsatility index that were 100% specific for malignancy. However, sensitivities for these cutoff values were 47% and 55%, respectively. Also, histologic examinations showed that most flow signals in nodes with malignant disease represented arterioles or veins in the septa between tumor nests or near the capsule. CONCLUSION: Unlike nodes with benign reactive disease, 98% of nodes with malignant disease and 100% of tuberculous nodes showed abnormal patterns of nodal vascularity. Also, high values for the resistive and pulsatility indexes were highly specific for malignant lymphadenopathy. Color Doppler sonography combined with analysis of spectral waveforms was useful in differentiating benign from malignant cervical lymphadenopathy.

Adolescent↗
PubMed1997

The etiology and clinical characteristics of mesenteric adenitis in Korean adults.

This study is aimed at investigating the etiology and clinical characteristics of mesenteric adenitis in Korean adults, prospectively. Clinical manifestations of fifteen patients who presented with the acute onset of right lower quadrant pain and sonographically enlarged mesenteric lymph nodes and normal appendix were evaluated. For etiologic diagnosis, stool culture, serologic test for Epstein-Barr virus, and Widal test were performed. Colonoscopy with mucosal biopsies and microbial tissue cultures were performed in 12 of 15 patients. Of fifteen patients 6 were male and the average age was 29.9 (17 approximately 41) years. Associated symptoms were diarrhea (80%), fever (73%), nausea and vomiting (27%). Right lower quadrant tenderness was observed in all cases but rebound tenderness was observed only in 26.7% of the cases. Etiology was identified in 7 cases (47%): 2 Yersinia enterocolitica infection, 2 non-typhoidal Salmonella infection, 2 tuberculosis, and 1 typhoid fever. In colonoscopic examination, signs of active inflammation were observed in 9 cases (75%) and inactive or normal findings in 3 cases (25%). All of our patients, except for the patients with tuberculosis and typhoid fever who needed specific antibiotic therapy, improved spontaneously without using antibiotics. In conclusion, the etiology of mesenteric adenitis in Korean adults seems to be different from that of western countries. Furthermore, mesenteric adenitis in Korean adults is a clinical syndrome, frequently found in a relatively young age group, which improves spontaneously unless specific anti-microbial agents are indicated by microbiological tests, such as tuberculosis or typhoid fever.

Adolescent↗
PubMed1996

Focal appendicitis confined to the tip: diagnosis at US.

PURPOSE: To evaluate the diagnostic value of graded-compression ultrasonography (US) for the diagnosis of focal appendicitis confined to the tip. MATERIALS AND METHODS: During a 4-year period, US was performed in 1,450 patients with clinically suspected acute appendicitis. Of these patients, 443 had appendicitis at pathologic examination, 20 of whom had focal appendicitis confined to the tip. Focal appendicitis confined to the tip was defined as occurring when the resected specimen had inflammation only at the distal third of the appendix. RESULTS: Of 20 patients with focal appendicitis confirmed at pathologic examination, 17 patients (85%) had focal appendicitis that was correctly diagnosed at US. The remaining three patients' appendices were diagnosed at US as normal (false-negative cases). Five patients had perforation at the tip, and one patient had an appendicolith. CONCLUSION: Although US appears to be fairly accurate in the diagnosis of focal appendicitis confined to the tip, the entire length of the appendix should be evaluated in order to avoid a false-negative diagnosis.

Acute Disease↗
PubMed1996

Appendicitis: usefulness of color Doppler US.

PURPOSE: To assess whether color Doppler ultrasonography (US) can help diagnose early acute appendicitis in appendices of equivocal size at gray-scale US. MATERIALS AND METHODS: In a retrospective study, color Doppler US findings were evaluated in 20 individuals with proved normal appendix at barium enema examination and in 50 patients in whom pathologic findings confirmed acute appendicitis. In a prospective study, the diagnostic value of hyperemia in the wall of the appendix in differentiating a normal from an inflamed appendix was evaluated in 26 patients with appendices of equivocal size (5-7 mm in maximal outer diameter) at grayscale US. RESULTS: In the retrospective study, 44 of the 50 patients had hyperemia at color Doppler US. The remaining six patients had no hyperemia, and pathologic findings confirmed gangrenous appendices. The 20 patients with proved normal appendix at barium enema examination had no detectable blood flow in the wall. In the prospective study, 10 of 26 patients had hyperemia at color Doppler US, and pathologic findings confirmed early acute appendicitis. Results of barium enema examination (n = 12) or clinical follow-up (n = 4) confirmed no appendicitis in the remaining 16 patients. CONCLUSION: Hyperemia in the wall of the appendix at color Doppler US is a sensitive indicator for inflammation. A simple additional color Doppler US examination may be helpful in the diagnosis of early acute appendicitis when an appendix is well depicted and is equivocal in size at gray-scale US.

Acute Disease↗
PubMed1996

[14C]7-ethoxycoumarin metabolism by precision-cut rat hepatic slices.

The metabolism of [14C]7-ethoxycoumarin ([14C]7-EC) has been studied in rat liver slice cultures in vitro by using a direct radiometric high-pressure liquid chromatography method. [14C]7-EC was extensively biotransformed in these incubations to 7-hydroxycoumarin (7-OHC), 7-hydroxycoumarin glucuronide, and 7-hydroxycoumarin sulfate, as well as to a large number of previously unrecognized metabolites, the majority of which are sulfate conjugates. The liver slice [14C]7-EC metabolite profile was also very complex and seemed to be qualitatively similar to the medium metabolite profile. Quantitative comparisons, however, demonstrated that there was approximately two to five times more 7-OHC in the liver slice than in the medium, whereas 7-hydroxycoumarin sulfate, the most abundant metabolite in the medium, was present only at low levels in the liver slice. These data demonstrate that 7-OHC levels are considerably underestimated when only levels in the medium are considered. Total metabolite levels were approximately equal in the medium and liver slice after a 2-hr incubation, with considerably higher total metabolite levels present in the medium at the end of the incubation period (8 hr). Additional studies are needed to identify the structures of the previously unrecognized metabolites observed in this study and the enzymes responsible for their formation, as well as studies to define the metabolism of [14C]7-EC in other in vitro models by using tissue from humans and other animal species.

Animals↗
PubMed1995

Congenital syphilis mimicking child abuse.

It has been reported that fractures complicating congenital syphilis can mimic child abuse. We present such a finding in an 8-week-old infant who presented with paralysis of the left arm.

Child Abuse↗
PubMed1995

PR interval behavior during exercise stress test.

OBJECTIVES: The PR interval on the electrocardiogram represents conduction time from the onset of atrial activation through His-Purkinje conduction system during a normal cardiac cycle. While its behavior at rest and during exposure to various cardioactive drugs is well documented, there exist few reports which describe PR interval variations during exercise in normal control and patient groups. In the present study, we examined the behavior of the PR intervals during various stages of exercise, and at the same time we observed whether the changes of PR interval during exercise could suggest that implanted cardiac pacemaker algorithms may be constructed to maximize hemodynamic benefits in patients requiring physiological cardiac pacemaker. METHODS: A retrospective analysis of the exercise treadmill test was performed on 148 healthy control group (148 males, mean age of 42.7 +/- 11.7) and 134 patient group (95 males & 39 females, mean age of 47.1 +/- 11.7) which had complained of non-specific chest symptoms but were identified as normal in the exercise treadmill test. During the test, we used the standard Bruce protocol. The results were expressed as mean +/- standard deviation, and differences in the mean value of each standard deviation, and differences in the mean value of each group were evaluated by the student's t-test. A P value of less than 0.05 was regarded as significant. RESULTS: 1) The control group showed 6.9msec reduction rate of the PR interval whenever their heart rate increased by 10 beats per minute. 2) The entire patients group showed 5msec reduction rate of the PR interval whenever their heart rate increased by 10 beats per minute. 3) The male patients group showed 5.2msec reduction rate of the PR interval whenever their heart rate increased by 10 beats per minute. 4) The female patient group showed 4.3msec reduction rate of the PR interval whenever their heart rate increased by 10 beats per minute. 5) There were significant differences of the PR interval changes between the entire or male patient group and the control group within the same range of heart rates. CONCLUSIONS: This study shows that PR interval changes corresponding to heart rate increments were linearly decreased. These changes of PR interval during exercise suggest that implanted cardiac pacemaker algorithms may be constructed to maximize hemodynamic benefits in patients requiring physiological cardiac pacemakers.

Adult↗
PubMed1994

Assessment of reducibility of ileocolic intussusception in children: usefulness of color Doppler sonography.

PURPOSE: To assess the diagnostic usefulness of ultrasonography (US) in intussusception in children and determine whether color Doppler sonography (CDS) can indicate bowel viability and help in prediction of reducibility. MATERIALS AND METHODS: US was used to examine 176 children in whom the presence of intussusception was clinically suspected. CDS was performed in 64 patients with 65 cases of intussusception proved with US. RESULTS: The positive US findings were confirmed with air enema; the negative findings, with air enema in 46 patients and clinical follow-up in 66 patients (100% specificity and sensitivity). CDS indicated blood flow in 62 of 65 cases of intussusception; pneumatic reduction was achieved in 58 (94%) of these 62 cases. Four patients (6%) underwent manual reduction of viable bowel; three patients (5%) who had no color Doppler signal underwent segmental resection. The difference in reduction rates based on blood flow was statistically significant (P = .0008). CONCLUSION: US is sensitive and specific in the diagnosis of intussusception, and CDS is a promising predictor of bowel viability.

Air Pressure↗
PubMed1993

Stereoselective disposition: enantioselective quantitation of 3,4-(methylenedioxy) methamphetamine and three of its metabolites by gas chromatography/electron capture negative ion chemical ionization mass spectrometry.

A new chiral assay for 3,4-(methylenedioxy)methamphetamine (MDMA) and three of its metabolites in biological specimens is based on direct aqueous derivatization with N-heptafluorobutyryl-S-prolyl chloride, followed by capillary chromatographic separation of the diastereomeric derivatives and detection by a mass spectrometer operated in the electron capture negative ion chemical ionization mode. The assay is linear from 5 to 1000 ng ml-1 for each enantiomer and allows simultaneous quantitation of MDMA and three of its metabolites in biological specimens. Investigation of the disposition of racemic MDMA in rats and mice revealed quantitative differences in the disposition of the enantiomers of MDMA in these species; the most noteworthy result was a two-fold greater urinary excretion of the neurotoxic S-(+)-MDMA by mice. Only MDMA and 3,4-(methylenedioxy)amphetamine (MDA) enantiomers were detected at measurable concentrations in the frontal cortices and hippocampis from rats dosed with 10 mg kg-1 of racemic MDMA; in this species the enantiomeric profiles of these two compounds were similar in brain and urine.

3,4-Methylenedioxyamphetamine↗
PubMed1993

Short-term effects of 2,4,5-trihydroxyamphetamine, 2,4,5-trihydroxymethamphetamine and 3,4-dihydroxymethamphetamine on central tryptophan hydroxylase activity.

In previous studies, we have reported the long-term effects of several metabolites of 3,4-methylenedioxymethamphetamine (MDMA) on tryptophan hydroxylase (TPH) activity. In this study, the short-term effects of three metabolites of MDMA. 2,4,5-trihydroxyamphetamine (THA), 2,4,5-trihydroxymethamphetamine (THM) and 3,4-dihydroxymethamphetamine, and the in vitro effect of THA on TPH activity are reported. After short-term treatment, hippocampal TPH activity was decreased to 8 and 54% of control in response to THA and THM, respectively, but was unaltered after 3,4-dihydroxymethamphetamine. Incubating TPH from THM-treated rats with dithiothreitol under nitrogen failed to reverse the decrease in enzyme activity induced by THM treatment. THA also decreased tyrosine hydroxylase activity to 75% of control, whereas the enzyme activity remained unaltered by THM. The structural analog of THA, 6-hydroxydopamine, failed to reproduce the effect of THA on TPH activity; however, 5,6-dihydroxytryptamine decreased hippocampal TPH activity to 18% of control. In the in vitro study, the hippocampus and the striatum were incubated in varying concentrations of THA. After a 1-h incubation at 37 degrees C, hippocampal TPH activity was decreased to 83, 71, 68, 47 and 3% of control after exposure to 0.001, 0.01, 0.1, 0.5 or 5.0 mM THA, respectively; striatal TPH activity was reduced to 98, 95, 70, 54 and 17% of control, respectively. Incubating the enzyme under reducing conditions failed to restore the enzyme activity to control levels.(ABSTRACT TRUNCATED AT 250 WORDS)

5,6-Dihydroxytryptamine↗
PubMed1992

Long-term alteration in the central monoaminergic systems of the rat by 2,4,5-trihydroxyamphetamine but not by 2-hydroxy-4,5-methylenedioxymethamphetamine or 2-hydroxy-4,5-methylenedioxyamphetamine.

The long-term effects of three metabolites of 3,4-methylenedioxymethamphetamine (MDMA) on the central monoaminergic systems of the rat were examined. Seven days after the intracerebroventricular administration of 0.25 and 0.5 mumol 2,4,5-trihydroxyamphetamine, hippocampal tryptophan hydroxylase (TPH) activity was reduced to 5 and 1% of control, respectively, while norepinephrine (NE) concentration was depressed to 10 and 18% of control. These two respective dosages also decreased striatal tyrosine hydroxylase (TH) activity to 67 and 10% of control, respectively, while nigral TH activity was reduced to 59 and 20% of control. Striatal TPH activity was reduced to 74 and 81% of control, respectively, while the activity in the dorsal and median raphe remained unaltered. The intracerebroventricular administration of 1 mumol 2-hydroxy-4,5-methylenedioxymethamphetamine (6-OH-MDMA) failed to alter TPH activity, TH activity or NE concentration after 14 days. In contrast, 1 mumol of 2-hydroxy-4,5-methylenedioxyamphetamine (6-OH-MDA) induced a 30% increase in striatal TPH activity and a 50% increase in nigral TH activity. The study of the formation of 2,4,5-trihydroxyamphetamine after MDMA treatment may provide insight as to how MDMA destroys serotonergic nerve terminals.

3,4-Methylenedioxyamphetamine↗
PubMed1992

Comparative investigation of disposition of 3,4-(methylenedioxy)methamphetamine (MDMA) in the rat and the mouse by a capillary gas chromatography-mass spectrometry assay based on perfluorotributylamine-enhanced ammonia positive ion chemical ionization.

A gas chromatography-mass spectrometry assay based on perfluorotributylamine-enhanced ammonia positive ion chemical ionization has been developed for MDMA and three of its primary metabolites in biological specimens; the assay is linear from 2 to 1000 ng ml-1. Quantitatively, more of an administered dose of 10 mg kg-1 MDMA was excreted by the mouse (72%) than by the rat (35%); most in both species was excreted in urine and within 24 h. The difference in per cent excretion is entirely due to proportionally greater excretion of the parent drug by the mouse. 4-Hydroxy-3-methoxymethamphetamine (HMM) is the major urinary metabolite in both species. HMM and another primary metabolite, 4-hydroxy-3-methoxyamphetamine (HMA), were excreted mainly as glucuronide and sulphate conjugates (> 85%).

3,4-Methylenedioxyamphetamine↗
PubMed1992

Diagnosis of acute appendicitis in pregnant women: value of sonography.

OBJECTIVE: The diagnosis of acute appendicitis in pregnant women often is difficult to make on the basis of clinical findings, and radiologic examination is limited because of the potentially hazardous effects of radiation. This study was done to assess the value of sonography in the diagnosis of acute appendicitis in pregnant women. SUBJECTS AND METHODS: We obtained sonograms in 45 pregnant women with clinically suspected acute appendicitis. Our sonographic technique included graded-compression scanning. The left lateral decubitus position was used in the third trimester of gestation. The sonographic criterion for the diagnosis of acute appendicitis was visualization of an incompressible appendix with a maximal diameter greater than 7 mm. We correlated the sonographic findings with the surgical findings in 22 cases and with the results of clinical follow-up in 23 cases. RESULTS: Sonography could not be used to make the diagnosis in three (7%) of 45 patients because the size of the gravid uterus prevented use of the graded-compression technique. These three patients were in the third trimester of pregnancy (greater than 35 weeks' gestation). Sonographic findings were used as a basis for diagnosis in 42 cases. Acute appendicitis was diagnosed on the basis of sonograms in 16 patients, and in all but one of these patients, acute appendicitis was confirmed by surgical and pathologic findings. In the 42 cases in which the imaging findings indicated the diagnosis, the overall sensitivity of sonography was 100%, the specificity was 96%, and the accuracy was 98%. CONCLUSION: Our experience suggests that graded-compression sonography is a valuable procedure for detecting acute appendicitis in pregnant women despite technical difficulty in performing it during the third trimester of pregnancy.

Acute Disease↗
PubMed1992

Effects of 3,4-dihydroxymethamphetamine and 2,4,5-trihydroxymethamphetamine, two metabolites of 3,4-methylenedioxymethamphetamine, on central serotonergic and dopaminergic systems.

The effects of 3,4-dihydroxymethamphetamine (DHM) and 2,4,5-trihydroxymethamphetamine (THM) on central serotonergic and dopaminergic systems were investigated to determine if these metabolites share the neurochemical properties of 3,4-methylenedioxymethamphetamine. THM (50-200 micrograms) or DHM (135 micrograms) was administered i.c.v. to rats; 5 days later, cortical, striatal and hippocampal tryptophan hydroxylase (TPH) activity were decreased by THM in a dose-dependent manner, whereas DHM was without effect in these brain structures. The concentration of serotonin in the brain structures contralateral to the side of THM injection was also decreased, but to a lesser degree. THM (100 and 200 micrograms) increased TPH activity to 155% of control in the dorsal raphe, whereas a dose of 50 micrograms increased TPH activity to 132% of control in the median raphe nucleus. THM also markedly reduced striatal tyrosine hydroxylase activity, but did not alter enzyme activity in the substantia nigra; DHM increased striatal tyrosine hydroxylase activity to 115% of control. These results suggest that THM, but not DHM, is toxic to both dopaminergic and serotonergic nerve terminals. Although THM could not be established as the neurotoxic metabolite explaining 3,4-methylenedioxymethamphetamine (MDMA) toxicity, its properties may prove useful in elucidating amphetamine toxicity.

3,4-Methylenedioxyamphetamine↗
PubMed1991

In vivo formation of aromatic hydroxylated metabolites of 3,4-(methylenedioxy)methamphetamine in the rat: identification by ion trap tandem mass spectrometric (MS/MS and MS/MS/MS) techniques.

Aromatic hydroxylation has been established as a pathway for the in vivo metabolism of 3,4-(methylenedioxy)methamphetamine (MDMA) in the rat. Hydroxylation occurred at positions 2, 5 and 6 of the 3,4-methylenedioxyphenyl ring, but is favored at the 6 position. All three regioisomers of both hydroxy-MDMA and hydroxy-3,4-(methylenedioxy)amphetamine (hydroxy-MDA) were detected in the rat liver when 20 mg kg-1 of MDMA was administered. However, 6-hydroxy-MDMA and 6-hydroxy-MDA were the only hydroxylated metabolites detected in the rat brain and plasma and no hydroxylated metabolites were detected in the urine. The hydroxylated metabolites were identified by co-injection of synthetic reference compounds and comparison of the mass spectra of the trifluoroacetyl derivatives of the metabolites with the synthesized reference compounds. The regioisomers of both hydroxy-MDMA and hydroxy-MDA could not be distinguished by either single-stage or two-stage mass analysis. However, employment of a third stage of mass analysis produced distinctly different mass spectra for each of the three regioisomers.

3,4-Methylenedioxyamphetamine↗