Executive Summary of the 2021 International Conference of Korean Dementia Association: A Report From the Academic Committee of the Korean Dementia Association

Recently, aducanumab, a beta amyloid targeted immunotherapy, has been approved by the US Food and Drug Administration for the treatment of Alzheimer’s dementia (AD). Although many questions need to be answered, this approval provides a promising hope for the development of AD drugs that could be supported by new biomarkers such as blood-based ones and composite neuropsychological tests that can confirm pathologic changes in early stages of AD. It is important to elucidate the complexity of AD which is known to be associated with other factors such as vascular etiologies and neuro-inflammation. Through the second international conference of the Korean Dementia Association (KDA), researchers from all over the world have participated in the exchange of opinions with KDA members on the most up-to-date topics. The Academic Committee of the KDA summarizes lectures to provide the depth of the conference as well as discussions. This will be an important milestone to widen the latest knowledge in the research of AD’s diagnosis, therapeutics, pathogenesis that can lead to the establishment of future directions.

Translocator Protein (18 kDa) Polymorphism (rs6971) in the Korean Population

Background@#and Purpose: The expression of the 18-kDA mitochondrial translocator protein (TSPO) in the brain is an attractive target to study neuroinflammation. However, the binding properties of TSPO ligands are reportedly dependent on genetic polymorphism of the TSPO gene (rs6971). The objective of this study is to investigate the rs6971 gene polymorphism in the Korean population. @*Methods@#We performed genetic testing on 109 subjects including patients with mild cognitive impairment, Alzheimer’s disease (AD) dementia, non-AD dementia, and cognitively unimpaired participants. Magnetic resonance imaging scans and detailed neuropsychological tests were also performed, and 29 participants underwent 18 F-DPA714 PET scans. Exon 4 of the TSPO gene containing the polymorphism rs6971 (Ala or Thr at position 147) was polymerase chain reaction amplified and sequenced using the Sanger method. The identified rs6971 genotype codes (C/C, C/T, or T/T) of the TSPO protein generated high-, mixed-, or lowaffinity binding phenotypes (HABs, MABs, and LABs), respectively. @*Results@#We found that 96.3% of the study subjects were HAB (105 out of 109 subjects), and 3.7% of the subjects were MAB (4 out of 109 subjects). 18 F-DPA-714 PET scans showed nonspecific binding to the thalamus and brainstem, and increased tracer uptake throughout the cortex in cognitively impaired patients. The participant with the MAB polymorphism had a higher DPA714 signal throughout the cortex. @*Conclusions@#The majority of Koreans are HAB (approx. 96%). Therefore, the polymorphism of the rs6971 gene would have a smaller impact on the availability of second-generation TSPO PET tracers.

18FTHK5351 PET Imaging in Patients with Mild Cognitive Impairment

Background@#and PurposeMild cognitive impairment (MCI) is a condition with diverse clinical outcomes and subgroups. Here we investigated the topographic distribution of tau in vivo using the positron emission tomography (PET) tracer [18F]THK5351 in MCI subgroups. @*Methods@#This study included 96 participants comprising 38 with amnestic MCI (aMCI), 21 with nonamnestic MCI (naMCI), and 37 with normal cognition (NC) who underwent 3.0-T MRI, [18F]THK5351 PET, and detailed neuropsychological tests. [18F]flutemetamol PET was also performed in 62 participants. The aMCI patients were further divided into three groups: 1) verbal-aMCI, only verbal memory impairment; 2) visual-aMCI, only visual memory impairment; and 3) both-aMCI, both visual and verbal memory impairment. Voxel-wise statistical analysis and region-of-interest -based analyses were performed to evaluate the retention of [18F]THK5351 in the MCI subgroups. Subgroup analysis of amyloid-positive and -negative MCI patients was also performed. Correlations between [18F]THK5351 retention and different neuropsychological tests were evaluated using statistical parametric mapping analyses. @*Results@#[18F]THK5351 retention in the lateral temporal, mesial temporal, parietal, frontal, posterior cingulate cortices and precuneus was significantly greater in aMCI patients than in NC subjects, whereas it did not differ significantly between naMCI and NC participants. [18F] THK5351 retention was greater in the both-aMCI group than in the verbal-aMCI and visualaMCI groups, and greater in amyloid-positive than amyloid-negative MCI patients. The cognitive function scores were significantly correlated with cortical [18F]THK5351 retention. @*Conclusions@#[18F]THK5351 PET might be useful for identifying distinct topographic patterns of [18F]THK5351 retention in subgroups of MCI patients who are at greater risk of the progression to Alzheimer's dementia.

Relationships between ¹⁸F-THK5351 Retention and Language Functions in Primary Progressive Aphasia

BACKGROUND AND PURPOSE: There are three distinct subtypes of primary progressive aphasia (PPA): the nonfluent/agrammatic variant (nfvPPA), the semantic variant (svPPA), and the logopenic variant (lvPPA). We sought to characterize the pattern of [¹⁸F]-THK5351 retention across all three subtypes and determine the topography of [¹⁸F]-THK5351 retention correlated with each neurolinguistic score. METHODS: We enrolled 50 participants, comprising 13 PPA patients (3 nfvPPA, 5 svPPA, and 5 lvPPA) and 37 subjects with normal cognition (NC) who underwent 3.0-tesla magnetic resonance imaging, [¹⁸F]-THK5351 positron-emission tomography scans, and detailed neuropsychological tests. The PPA patients additionally participated in extensive neurolinguistic tests. Voxel-wise and region-of-interest-based analyses were performed to analyze [¹⁸F]-THK5351 retention. RESULTS: The nfvPPA patients exhibited higher [¹⁸F]-THK5351 retention in the the left inferior frontal and precentral gyri. In svPPA patients, [¹⁸F]-THK5351 retention was elevated in the anteroinferior and lateral temporal cortices compared to the NC group (left>right). The lvPPA patients exhibited predominant [¹⁸F]-THK5351 retention in the inferior parietal, lateral temporal, and dorsolateral prefrontal cortices, and the precuneus (left>right). [¹⁸F]-THK5351 retention in the left inferior frontal area was associated with lower fluency scores. Comprehension was correlated with [¹⁸F]-THK5351 retention in the left temporal cortices. Repetition was associated with [¹⁸F]-THK5351 retention in the left inferior parietal and posterior temporal areas, while naming difficulty was correlated with retention in the left fusiform and temporal cortices. CONCLUSIONS: The pattern of [¹⁸F]-THK5351 retention was well matched with clinical and radiological findings for each PPA subtype, in agreement with the anatomical and functional location of each language domain.

Glucose Hypometabolism in Hippocampal Subdivisions in Alzheimer's Disease: A Pilot Study Using High-Resolution ¹⁸F-FDG PET and 7.0-T MRI

BACKGROUND AND PURPOSE: Atrophy of the hippocampus is an important clinical diagnostic marker of Alzheimer's disease (AD), and so assessments of hippocampal activity and its subdivisions might provide invaluable information. This study compared the glucose metabolism of hippocampal subdivisions in mild-AD patients and healthy controls. METHODS: High-resolution T2*-weighted gradient-echo magnetic resonance imaging (MRI) images and ¹⁸F-fluorodeoxyglucose (FDG) positron-emission tomography (PET) images were acquired using 7.0-T MRI and high-resolution research tomograph FDG-PET, respectively, in 9 early-stage AD patients and 10 healthy subjects. The hippocampal body was divided into three equal parts (anterior, middle, and posterior), and in each part a region of interest (ROI) was drawn over the cornus ammonis (CA)1, CA2/3, CA4/dentate gyrus (DG), and subiculum. The standardized uptake values of the hippocampal subdivisions were calculated for each ROI as ratios relative to the pons standardized uptake value. Statistical analysis was conducted using the Mann-Whitney U test. RESULTS: Patients with early-stage AD patients showed significantly less metabolic activity than healthy controls focally in the middle (p=0.050) and posterior (p=0.034) CA2/3 regions of the right hippocampus, and significantly less activity throughout the left hippocampal body in the anterior CA2/3 (p=0.027) and CA4/DG (p=0.027) regions, the middle CA1 region (p=0.011), and the posterior CA1 (p=0.034), CA2/3 (p=0.007), and CA4/DG (p=0.014) regions. CONCLUSIONS: It was possible to use high-resolution PET-MRI fusion images to identify hippocampus subdivisions and assess glucose metabolism in the subfields. Reductions in metabolic activity were found to vary along the hippocampal axis in early-stage AD patients.

Age-Related Changes in Nuclear Factor Erythroid 2-Related Factor 2 and Reactive Oxygen Species and Mitochondrial Structure in the Tongues of Fischer 344 Rats

OBJECTIVES: Previously the authors reported age-related changes in the activities of anti-oxidative enzyme activities and protein expressions in the tongues of rats. Because more information is required about relations between aging and oxidative stress and anti-oxidative enzyme efficiency, the authors investigated differences between the expression of master regulator of anti-oxidative enzymes (nuclear factor erythroid 2-related factor 2 [Nrf2]), levels of reactive oxygen species (ROS), and mitochondrial structures in the tongues of young and aged Fischer 344 rats. METHODS: Age-dependent changes in Nrf2 protein and ROS were determined by Western blotting and using chemical kits, respectively. Tongue specimens were examined by electron microscopy. The study was conducted using rats aged 7 months (young, n=8) or 22 months (old, n=8). RESULTS: Nrf2 protein levels in the tongues of aged rats were lower than in young rats. ROS levels were higher in older rats and mitochondrial structural deficits were observed their tongues. Three young rats showed moderate mitochondrial degeneration, whereas profound degeneration with mitochondrial cristae disruption, swelling, rupture, or intramitochondrial vacuole formation was observed in all 8 old rats. Notably, mitochondrial rupture was observed in 5 old rats. CONCLUSION: Antioxidant defense systems of old rats were compromised by Nrf2 deficiency, which could lead to the deleterious accumulation and release of ROS and probably mitochondrial structural deficits in aged tongue tissues.

Interrelated Atrioventricular Reentrant Tachycardia and Idiopathic Left Ventricular Tachycardia in a Patient with Manifested Bystander Accessory Pathway

Double tachycardia is defined as the coexistence of supraventricular tachycardia (SVT) and ventricular tachycardia (VT). In clinical practice, incidentally encountered double tachycardia is difficult to diagnose during electrophysiology study without prior documentation of both tachycardias. SVT can be confused with VT because SVT sometimes show an aberrant conduction depending on heart rate. In the present case, a patient with Wolff-Parkinson-White syndrome exhibited atrioventricular reentrant tachycardia (AVRT) via a concealed bypass tract and idiopathic left ventricular tachycardia (ILVT), which were difficult to discriminate because of their similar cycle length and interrelationship.

Ideographic Alexia without Involvement of the Fusiform Gyrus in a Korean Stroke Patient: A Serial Functional Magnetic Resonance Imaging Study

BACKGROUND: Korean orthography is composed of Hanja (ideograms) and Hangul (phonograms). Based on previous studies, the fusiform gyrus has been associated with ideogram reading. We examine serial functional magnetic resonance imaging (fMRI) images in a patient exhibiting dissociation of Hanja and Hangul reading to identify brain areas associated with Hanja reading. CASE REPORT: fMRI were taken of a 63-year-old man showing profound Hanja alexia with normal Hangul reading after an acute stroke involving the left frontal and parietal lobes, who later spontaneously recovered his Hanja reading ability. Scans were taken while performing Hanja and Hangul reading tasks on three occasions. As a result, in spite of having profound Hanja alexia, partial activation of the fusiform gyrus was observed on the first fMRI. Serial fMRI scans showed activation of the bilateral middle frontal gyri that increased in parallel with the patient's recovery of Hanja reading. CONCLUSIONS: The frontal lobe, not only fusiform gyrus, may play role in reading Hanja, although more evidence is needed.

Evaluation of Eye Irritation Potential of Solid Substance with New 3D Reconstructed Human Cornea Model, MCTT HCE(TM)

The eye irritation potential of drug candidates or pharmaceutical ingredients should be evaluated if there is a possibility of ocular exposure. Traditionally, the ocular irritation has been evaluated by the rabbit Draize test. However, rabbit eyes are more sensitive to irritants than human eyes, therefore substantial level of false positives are unavoidable. To resolve this species difference, several three-dimensional human corneal epithelial (HCE) models have been developed as alternative eye irritation test methods. Recently, we introduced a new HCE model, MCTT HCETM which is reconstructed with non-transformed human corneal cells from limbal tissues. Here, we examined if MCTT HCETM can be employed to evaluate eye irritation potential of solid substances. Through optimization of washing method and exposure time, treatment time was established as 10 min and washing procedure was set up as 4 times of washing with 10 mL of PBS and shaking in 30 mL of PBS in a beaker. With the established eye irritation test protocol, 11 solid substances (5 non-irritants, 6 irritants) were evaluated which demonstrated an excellent predictive capacity (100% accuracy, 100% specificity and 100% sensitivity). We also compared the performance of our test method with rabbit Draize test results and in vitro cytotoxicity test with 2D human corneal epithelial cell lines.

Development-assistance Strategies for Stroke in Low- and Middle-income Countries

While communicable diseases still pose a serious health threat in developing countries, previously neglected health issues caused by non-communicable diseases such as stroke are rapidly becoming a major burden to these countries. In this review we will discuss the features and current status of stroke in low- and middle-income countries (LMICs). Overall the global burden of hemorrhagic stroke is larger than ischemic stroke, with a disproportionately greater burden, measured in incidence and disability-adjusted life-years, regionally localized in LMICs. Patients in poorer countries suffer due to insufficient primary care needed to control risk factors such as hypertension, and inadequate emergency care systems through which sudden events should be managed. In light of these situations, we emphasize two strategic points for development assistance. First, assistance should be provided for bolstering, integrating, and coordinating both the primary health and emergency care systems, in order to prevent stroke and strengthen stroke management, respectively. Second, the assistance needs to focus on programs at the community level, to reduce life-style risks of stroke in a more sustainable manner, and to improve stroke outcomes more effectively.

Transient Contralateral Tactile and Auditory Extinction After Left Thalamic Hemorrhage

Right-sided neglect after an acute, left subcortical brain injury is a rare phenomenon for several reasons including its rapid resolution and decreased clinical suspicion. Here we present a case of a 72-year-old right-handed man who presented with right auditory and sensory extinction following a left thalamic intracerebral hemorrhage without visual extinction, sensory or corticosensory deficits, and discuss the mechanisms involved in this infrequently encountered stroke syndrome.

Resonance Frequency Analysis in Non-Submerged, Internal Type Implant with Sinus Augmentation Using Deproteinized Bovine Bone Mineral

The Use of Bispectral Analysis and Hemodynamic Monitoring in Patients Undergoing Intravenous Sedation for Minor Oral Surgery

Hemodynamic Comparison between Bupivacaine and Levobupivacaine Induced Cardiovascular Collapses in Anesthetized Dogs / 대한구급학회지

BACKGROUND: Levobupivacaine is known to be less cardiotoxic than racemic bupivacaine but some authors have reported there were no differences in cardiotoxic profiles between two agents. We will investigate the full course to cardiovascular collapse induced by bupivacaine stereoisomers in anesthetized dogs and would find out the differences if any, and explain the causative factors. METHODS: Twenty dogs were assigned to two groups, racemic bupivacaine group (BUP) and levobupivacaine group (LBUP), equally (n=10, each). Under general anesthesia each drug was infused continuously (0.5 mg/kg/min) until cardiovascuar collapse (CVC, MAP=40 mmHg) occurred. During the experiment, hemodynamic data, CO, SVR, PVR, ECG parameters and drug concen tration were gathered and analyzed. RESULTS: Two groups were not different in terms of dose for CVC, plasma drug concentration and time for CVC. MAP maintained initial values during the early period and declined during the late period without any between-group difference. Otherwise CO decreased continuously and significantly higher in LBUP than in BUP throughout. Calculated SVR showed the same feature as CO in opposite direction and was higher in BUP. Correlation test revealed high correlation between CONC and SVR or PVR and between CO and cSvO2. CONCLUSIONS: In assessment of cardiovascular collapse induced by stereoisomers of bupivacaine, monitoring with only MAP can lead to misinterpretation and invasive monitoring including CO or cSvO2 measurement might be needed.

Adenovirus and Lipofectin Mediated p53 Gene Transfection Efficiency in Human Cervical Cancer Cell Lines and Xenografted Nude Mouse / 대한산부인과학회잡지

BACKGROUND: The classical treatment of the cervical cancer is surgery, radiotherapy, chemotherapy. Even though the improvement of treatment successful rate, conventional therapy has some limitations. Recent cutting edge of cancer therapy has been developed in gene level including understand the biological characteristics of the cancer cells, enhance the human immune response, suppress the cancer cell proliferation. Therefore, the gene therapy is proposed to new treatment strategy. PURPOSE: The transfection efficiency of cervical cancer cell lines and cervical cancer cell line xerografted nude mouse was investigated by transfection of liposome and infection of adenovirus mediated suppressor(p53) and reportor(LacZ) gene. METHOD: The cervical cancer cell lines was used in this study were CaSki, SiHa (HPV16 positive, wild type p53 gene), HeLa, HelaS3(HPV18 positive, wild type p53 gene) and C33A, HT3(HPV negative, mutant p53). Direct plasmide and AdCMVp53 gene transfection was performed by using liposome system (pRcCMVLacZ / lipofectin, FuGene 6, Ca-phosphate). LacZ gene was used as the reportor gene for the transfection efficiency evaluation. Expression of p53 in cell lines and tumor tissue was confirmed by western blot and immunohistochemical staining. Xenografted nude mouse of SiHa cell line was infected by AdCMVp53 and AdCMVLacZ. Transfection efficiency was observed by same as above. RESULTS: In cervical cancer cell lines, gene transfection using liposome system(pRcCMVLacZ/lipofectin, FuGene 6, Ca-phosphate)revealed different transfection efficiency, especially pRcCMVLacZ in Fugene 6 showed 18-40% of high transfection efficiency in 6 cervical cancer cell lines by X-gal staining and AdCMVp53 showed 95-98% of the high transfection efficiency in HeLa, C33A. AdCMVp53 was significantly expressed at 2-5days after injection xenografted nude mouse on the western blot and transfection efficiency was 19.79+/-5.36, 26.26+/-11.69, 14.77+/-3.98,15.99+/-6.43%(day1-5). AdCMVLacZ were found to immuno- histochemistry analysis, in vivo transfection efficiency was 61.26+/-4.66,59.63+/-9.12, 29.46+/-14.33, 31.73+/- 22.64%(day 1-5) atx200 and 88.65+/-8.65, 70.85+/-20.94, 40.75+/-25.44, 48.21+/-10.97% (day 1-5) atx400. CONCLUSION: As a results, adenovirus-mediated transfection efficiency was higher in vivo experiment compared to cell lines. These high efficiency of adenovirus-mediated suppressor gene(p53) could become a significant meaningful data gene therapy strategy both transgenic mice and cervical cancer cell lines.

High Signal Intensity on T1-Weighted MR Image Related to Vacuum Cleft in the Intervertebral Disk: Clinical and Phantom Study

PURPOSE: To determine the possible mechanism by which an area of high signal intensity appears on T1-weighted MR images adjacent to a vacuum cleft in intervertebral disks. MATERIALS AND METHODS: We analyzed a total of 14 disks in nine patients in whom a vacuum cleft with T1-signal hyperintensity was observed. Lesions were present from T11-12 to L5-S1 using a 1.5-T whole-body imager, sagittal spine-echo T1-weighted and gradient-echo images (flip angle, 20 'and 60 ) were obtained. In order to identify the vacuum cleft, using plain radiographs in all patients and CT scans in two were also obtained. A 3% agar-gel block containing empty slits to form a magnetic susceptibility difference, a phantom was designed. The air spaces were 1.6 mm in thickness, 25 mm in width, and 20 to 25 mm in depth with 1.6-mm spacing. RESULTS: In all patients, vacuum clefts were confirmed by plain radiographs and CT scans. At the level containing air, T1-weighted images (both spin-echo and gradient-echo) showed a signal void resulting from the intervertebral disk vacuum cleft. A hyperintense band adjacent to the vacuum cleft was, however, observed. A gradient-echo image with a 60 'flip angle showed a brighter signal intensity than one with a 20 'angle. Our phantom study gave the same results. CONCLUSION: The magnetic susceptibility artifact may be responsible for the T1-signal hyperintensity observed adjacent to the vacuum cleft in intervertebral disks. In addition, in order to generate signal hyperintensity, the desiccating disk material must contain a certain amount of water molecules.

High Signal Intensity on T1-Weighted MR Image Related to Vacuum Cleft in the Intervertebral Disk: Clinical and Phantom Study

PURPOSE: To determine the possible mechanism by which an area of high signal intensity appears on T1-weighted MR images adjacent to a vacuum cleft in intervertebral disks. MATERIALS AND METHODS: We analyzed a total of 14 disks in nine patients in whom a vacuum cleft with T1-signal hyperintensity was observed. Lesions were present from T11-12 to L5-S1 using a 1.5-T whole-body imager, sagittal spine-echo T1-weighted and gradient-echo images (flip angle, 20 'and 60 ) were obtained. In order to identify the vacuum cleft, using plain radiographs in all patients and CT scans in two were also obtained. A 3% agar-gel block containing empty slits to form a magnetic susceptibility difference, a phantom was designed. The air spaces were 1.6 mm in thickness, 25 mm in width, and 20 to 25 mm in depth with 1.6-mm spacing. RESULTS: In all patients, vacuum clefts were confirmed by plain radiographs and CT scans. At the level containing air, T1-weighted images (both spin-echo and gradient-echo) showed a signal void resulting from the intervertebral disk vacuum cleft. A hyperintense band adjacent to the vacuum cleft was, however, observed. A gradient-echo image with a 60 'flip angle showed a brighter signal intensity than one with a 20 'angle. Our phantom study gave the same results. CONCLUSION: The magnetic susceptibility artifact may be responsible for the T1-signal hyperintensity observed adjacent to the vacuum cleft in intervertebral disks. In addition, in order to generate signal hyperintensity, the desiccating disk material must contain a certain amount of water molecules.

Imaging of Melorheostosis: Emphasis on MR Imaging Findings

PURPOSE: To evaluate the usefulness of various radiographic imaging modalities in the diagnosis and characterization of melorheostosis. MATERIALS AND METHODS: We retrospectively evaluated the plain film (n=8), computed tomographic (CT) imaging (n=5) and magnetic resonance (MR) imaging (n=5) findings of eight patients with melorheostosis diagnosed by bone biopsy (n=4) and characteristic radiographic findings (n=8). MR images were obtained with a 1.5-T scanner focused on the region of maximal radiographic abnormality. Pulse sequences include T1-weighted SE, T2-weighted fast SE (n=5) and postcontrast imaging (n=4). In order to define subtle enhancement of the lesions, subtraction MR images were obtained in one case. Imaging findings were analyzed with particular emphasis on the distribution of lesions along the sclerotome, differential radiographic findings between diaphyseal and metaepiphyseal lesions of the long bones, as seen on plain radiographs, and the density and signal characteristics of hyperostotic, lesions, as seen on CT and MR images. RESULTS: Characteristic distribution along the sclerotome was identified in five of eight cases mainly along C6 and 7 (n=2) and L3, 4 and 5 (n=3) sclerotomes. In diaphyseal melorherostosis (8/8), a characteristic finding, i.e., a wax flowing down from the candle, was identified on plain radiographs. In all three patients with metaepiphyseal melorheostosis (3/8), multiple round or oval hyperostotic lesions were seen in the epiphysis and metaphysis of the long bones. On CT, the marrow cavity was partly obliterated by hyperostotic lesions in all five patients with endosteal hyperostosis. Among these, central ground glass opacity with a sclerotic rim was seen in three patients. Periosteal hyperostosis was seen in two of five cases, being visualized as irregular excrescences in the periosteal region and surrounding soft tissue. Individual hyperostosis was visualized as hypointense on T1-weighted images and as a hyperintense center with a surrounding hypointense rim on T2-weighted images (5/5). On postcontrast images, central enhancement was noted in all four cases. In one of these, in which the degree of central enhancement was subtle, subtraction images (postcontrast SE- precontrast SE) also revealed a central signal increment. Central enhancement corresponded to the hyperintense center seen on T2-weighted images (4/4) and the ground-glass opacity seen on CT (2/2). CONCLUSION: Radiographic imaging plays a crucial role in the diagnosis of melorheostosis. The future role of gadolinium-enhanced MR imaging in the characterization of the lesion may be important though further evaluation and pathologic correlation is required.

Association of QT Dispersion with Left Ventricular Hypertrophy in Essential Hypertensives

BACKGROUND: Left ventricular hypertrophy(LVH) is a powerful indepedent risk factor of ventricular tachycardia and sudden death. Even though it is not clear the mechanism of sudden death in patients with LVH, inhomogenous ventricular repolarization is highly suggested. QT dispersion which reflecting regional inhomogeneity of repolarization is defined as interlead variation in QT intervals of 12 leads ECG. The purpose of this study was to assess whether QT dispersion is associated with LVH in hypertensive patients. METHODS: We assessed 23 untreated hypertensives with echocardiographic LVH and normal left ventricular systolic function. The criteria of 5th Joint National Committee stage I-III was used to define hypertension. Thirty four normotensives was assessed as controls. On a standard 12 lead ECG, the intervals between onset of QRS to end of T wave were measured(QT intervals) and corrected by heart rate(QTc). QT dispersion was calculated by the difference of maximal and minimal QTc. Left ventricular mass(LVM) was calculated from Devereux's formula using the parameters measured by the recommendation of American Society of Echocardiography. LVH was defined by LVM indices over 130 g/m2. RESULTS: LVM indices of hypertensive group were significantly greater than those of controls (162.2+/-39.3 g/m2 vs 84.2+/-16.1 g/m2, p<0.001). Maximal QT and QTc of hypertensive group were significantly prolonged than those of controls(maximal QT=401+/-31 ms vs 380+/-35 ms, p<0.05 ; maximal QTc=432+/-19 ms vs 414+/-17 ms, p<0.001). QT dispersions were significantly greater in hypertensive group than in controls(60.2+/-15.7 ms vs 33.2+/-11.7 ms, p<0.001). In hypertensive group, there was significant association between LVM index and QT dispersion(r=0.492, p=0.017). CONCLUSIONS: Hypertensives with LVH have a prolonged QT and QTc and increased QT dispersion in comparision with controls. QT dispersion in these patients correlates with degree of LVH.

Effects of irradiation with Cobalt 60 to the development of Ascaris eggs in stool

This study was carried out in order to find out the valuable measure to kill the parasite eggs in night soil. The fresh eggs of Ascaris put into human stool were irradiated with Cobalt 60 of 200,000 to 1,000,000 rad and cultured in test tubes at 25-30 C, washing with 2 percent formalin solution every 24 hours. The continuous development of those eggs were observed under microscope and the proprotions of developed eggs were compared with those of control groups. The major result can be summarized as follows: In general, The eggs in stool developed poorly than the eggs in saline. If the eggs were irradiated with the larger dose of Cobalt 60, the proportion of developed eggs were reduced subsequently. The eggs irradiated with the dose of 1,000,000 rad in saline developed in the proportion of 15.5 percent, whereas irradiated with 200,000 rad 94 percent developed in 4 weeks. The 44.5 percent of eggs in stool irradiated with 200,000 rad developed after 4 weeks, 30.5 percent with 300,000 rad, 25 percent with 500,000 rad and 3.5 percent with 1,000,000 rad respectively. The effective minimum dose of Cobalt 60 irradiation to kill the Ascaris eggs in stool was estimated 1,000,000 rad. Further examination will be required to observe the infectivity of irradiated Ascaris eggs to animals and to evaluate the effect from the standpoint of sanitary engineerings.