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Biomedical subjects

H Koo

Publications and source records attributed to H Koo.

35 records · Page 2Linked to original sources
PubMed1999

Predictors of in-hospital mortality following operative management of hip fractures.

OBJECTIVE: To identify predictors of in-hospital mortality and hospital stay following hip fractures. DESIGN: Retrospective cohort study of 185 consecutive patients. SETTING: Tertiary Care University Hospital. PARTICIPANTS: Individuals requiring operative treatment of a proximal femoral fracture excluding those individuals < 50 years old, with femoral head or subtrochanteric fractures, and significant co-morbidity. OUTCOMES: In-hospital mortality and length of hospital stay (days). RESULTS: 116 patients met the inclusion criteria. Predictors of in-hospital mortality from logistic regression analysis included male gender (odds ratio with 95% CI: 5.5, 1.5-20.5), admission from a long term care facility (5.5, 1.4-22.6), age greater than 90 years (4.5, 0.9-22.1), and living at home with support (0.2, 0.03-0.9). Predictors of hospital stay from multivariate regression analysis in order of magnitude included presence of a post-operative complication (odds ratio with 95% CI: 14.1, 4.7-44), living at home with support (3.4, 1.3-8.9) and older age (> 85 years) (2.7, 1.0-7.3). Moreover, confusion, urinary tract infections and decubitus ulcers accounted for greater than 50% of all complications encountered. A trend between the number of positive predictors and length of hospital stay was observed. CONCLUSIONS: Elderly individuals admitted from a long term care facility are at high risk of mortality following operative fixation of hip fractures. Early recognition and aggressive management of post-operative complications such as confusion, urinary tract infections and decubitus ulcers through careful patient monitoring may decrease hospital stays in those that survive.

Aged↗
PubMed1997

Effect of optic disc size or age on evaluation of optic disc variables.

AIMS/BACKGROUND: It has been reported that the number of optic nerve fibres decrease with age, and the cup/disc (C/D) ratio increases as the optic disc size increases. Consequently, the normal value of the optic disc variables measured by an optic disc analyser may change according to the optic disc size or age. The effect of individual variations in optic disc size or age on interpretation of optic disc variables was investigated. METHODS: Topographic optic disc variables of 104 normal Asian adults of both sexes aged 40 to 68 were measured using a confocal scanning laser ophthalmoscope (TopSS, Laser Diagnostic Technologies, Inc). Fourteen variables were evaluated according to the optic disc size or age. Statistical analysis was done by regression analysis. RESULTS: With an increase in optic disc size, the increase in cup shape, effective area, 1/2 depth area, C/D ratio, neuroretinal rim area, volume above, volume below, and 1/2 depth volume were statistically significant (p < 0.05). However, contour variation, mean contour depth, average depth, maximum depth, average slope, and maximum slope were not affected (p > 0.1). Age did not have any significant influence on optic disc variables (p > 0.1). CONCLUSION: Optic disc size, but not age, should be considered in the interpretation of optic disc variables.

Adult↗
PubMed1997

Adult T-cell leukemia/lymphoma with features of CD30-positive anaplastic large cell lymphoma--a case report.

We experienced a 58-year-old Korean man with adult T-cell leukemia/lymphoma with features of histologically anaplastic large cell lymphoma involving the skin and testis. The patient had cutaneous nodules in both extremities and a palpable right testicular mass. Right orchiectomy was performed and specimens of removed testicle and skin nodules showed immunohistologically anaplastic large cell lymphoma with T-cell phenotype, and CD30 antigen was positive. A human T-cell lymphotropic virus type 1 (HTLV-1) antibody titer was over 1 : 256 and integration of HTLV-1 proviral DNA pX gene was identified in the peripheral blood mononuclear cells and lymphoma tissue by polymerase chain reaction. Peripheral blood and bone marrow did not show any evidence of characteristic neoplastic T-cells.

Diagnosis, Differential↗
PubMed1996

Immunohistochemical expression of phospholipase C in global and focal ischemic encephalopathy in gerbil: relationship with morphological changes.

Phospholipase C (PLC) and related enzymes in signal transduction system are closely linked to cellular damage in ischemic encephalopathy. This study was undertaken to elucidate the time sequential changes of PLC isoenzymes (beta and gamma) in vulnerable areas of hippocampus in global ischemia and infarcted area in focal infarction. Mongolian gerbils were used because of their susceptibility to ischemic encephalopathy and divided into the following groups: the bilateral ischemia with various reperfusion periods group, unilateral progressive ischemia group, and focal ischemia group induced by infusion of iron particles through the femoral artery. The changes of PLC isoenzymes were observed immunohistochemically and matched with morphological changes. In the global ischemia with reperfusion group, the changes were most significant in hippocampus. Sequential changes of neurons such as red neurons at an early stage progressed to pknotic neurons at a later stage were noted with typical delayed neuronal damage in the corns ammonis (CA) 1 subfield of hippocampus. Red neurons and pyknotic neurons as well as intracytoplasmic inclusion in 3 to 24 hours of reperfusion showed loss of PLC isoenzymes as well as tubulin. The changes of PLC expression were corresponding to the degeneration of neurons with no discernible time sequential changes in remaining neurons. In the unilateral hemispheric progressive ischemia group, ischemic damage was far more marked and extensive with no selective injury pattern according to time and location. At 1 day, there was diffuse vacuolization and necrosis of neuropil with a loss of neuron. Admixed surviving neurons and vacuolated neuropil showed increased reaction to anti-PLC antibodies, which could be either an evidence of protein synthesis responding to ischemic insult or an artifactual change. Focal ischemia group showed time sequential changes of blood vessels and white blood cells with necrosis of surrounding tissue. Degenerating hippocampal neurons in infarction also showed a strong positive reaction to anti-PLC antibody, which was most likely due to condensation of cytoplasm rather than increased synthesis. This study showed different changes of PLC expression in global ischemic encephalopathy with reperfusion, progressive ischemia, and focal infarction, which suggested different pathophysiologic mechanism between these conditions.

Animals↗
PubMed1995

Eye primordium transplantation in Xenopus embryo.

A part of the eye primordium, the presumptive retinal anlage, was transplanted from stage-23/24 Xenopus borealis to replace the removed olfactory anlage of Xenopus laevis. Cells of the two species can be distinguished under fluorescence microscopy, and we used the resulting chimeras to determine whether the transplanted eye primordium would inhibit the regeneration of the olfactory anlage, whether it would connect with its usual target, the diencephalon, and whether migration of cells would occur from the transplant to the host CNS or from the host CNS to the transplant. In all cases, the olfactory anlage regenerated promptly, and normal olfactory bulbs developed. Omission of the eye stalk in the transplant resulted in failure of an optic nerve to develop from the developing retina. A cellular bridge containing the optic axons connected the transplanted retina to the diencephalon. Cells from the transplant migrated freely through the cellular bridge to several CNS regions. Their morphology, topographic arrangement, number, and relations with other host elements are consistent with the hypothesis that these cells belong to both glia and neuron types.

Animals↗
PubMed1995

Cell migration from the transplanted olfactory placode in Xenopus.

The eye vesicle of Xenopus borealis has been replaced with the transplanted olfactory primordium from Xenopus laevis in an attempt to determine whether cells from the transplant could migrate along the regrowing olfactory nerve and become incorporated into the CNS of the host. The use of X. laevis and X. borealis pairs allowed us to distinguish the cells of the host from those of the donor at the cellular level by means of the characteristic fluorescent nuclear spots (Q bands) of X. borealis. Transplantation was performed on pairs of animals at stages 23/24. The olfactory anlage was readily incorporated into the host, often fusing with the host homolateral organ and inhibiting the regrowth of the eye vesicle. An olfactory nerve developed from the transplanted organ. In the majority of cases, the nerve reached the diencephalon at the level of entrance of the optic nerve. Along the nerve originating from the transplanted organ we observed a stream of cells with the characteristics of the donor. These cells penetrated the host's CNS and became incorporated into it. The nature of these cells has not been ascertained by specific neuronal markers. However, on the basis of their morphology and disposition, the hypothesis suggested is that some of the migrating cells are neurons.

Animals↗
PubMed1991

Congenital hydrocephalus associated with anomalies of midline telencephalic structures. A case report.

Hydrocephalus is classified into communicating, if cerebrospinal fluid (CSF) can flow freely from the ventricle to the subarachnoid space, and into non-communicating, if it cannot. The cause of hydrocephalus is diverse, either congenital or acquired conditions causing obstruction to the flow of CSF. The location of the lesion is more important than the size or nature of the lesion. We describe an unusual case of congenital communicating hydrocephalus associated with multiple malformations of midline telencephalic structures. This was a premature male baby of 30 weeks gestational age. The pregnancy was terminated after revealing a hydrocephalus by ultrasonography. The cerebral hemispheres showed marked thinning of parenchyme with dilated lateral ventricles, communication of lateral and third ventricles with dilated foramina of Monro, absence of the septum pellucidum, and hypoplasia or focal agenesis of posterior portion of corpus callosum with dorsal dilation of the third ventricle. The right fornix appeared as a single thick midline cord in its approximately normal position and the hippocampi were poorly developed, especially in the left side. The left fornix was rudimentary.

Humans↗
PubMed1991

Congenital hydrocephalus--analysis of 49 cases.

The causes of congenital hydrocephalus vary widely and have an important effect in determining the future counseling of affected cases. We analyzed the postmortem findings of 49 autopsies diagnosed as hydrocephalus to find the causes and related conditions. The cases were collected during the last 10 years (1981-1990). The cases consisted of 25 cases associated with various congenital malformations of the central nervous system (CNS), 14 cases of posthemorrhagic hydrocephalus, 4 cases of postinfection hydrocephalus, and 2 cases of hydranencephaly. Four cases were associated with supracerebellar arachnoid cyst (1) and unknown causes (3). Twenty-five cases associated with congenital malformation of the CNS consisted of 10 cases of holotelencephaly, 5 cases of stenosis of the Sylvian aqueduct, 4 cases of agenesis of the corpus callosum, and 3 cases each of Dandy-Walker malformation and Arnold-Chiari malformation. Various malformations of other organs were associated with these cases. Cardiovascular malformations were common, consisting of 11 cases of patent ductus arteriosus (PDA), 7 cases of atrial septal defect (ASD), and 6 cases of patent foramen ovale (PFO). Among the anomalies of the respiratory system, abnormal lobation was commonly associated, as well as hypoplasia of the lung. Gastrointestinal malformations included Meckel's diverticulum, diaphragmatic hernia, mobile intestine, and midline small liver. Cryptorchidism was the most common malformation in the genitourinary system. Holotelencephaly cases showed multiple craniofacial anomalies, as well as other malformations in the central nervous system. Skeletal malformations included polydactyly, simian crease, and flexion deformity. There were no specific constellations of malformations in these different groups of CNS malformations associated with hydrocephalus.

Abnormalities, Multiple↗
PubMed1988

Astrocyte response to perinatal liver disease, hyperammonemia, and hyperbilirubinemia: an immunohistochemical study.

Astrocytic reaction to perinatal brain damage, which is caused by hyperammonemia, liver disease, hyperbilirubinemia, and a few other conditions, was studied using immunohistochemical methods for the demonstration of glial fibrillary acidic protein (GFAP). We found no increase in GFAP expression in those areas where Alzheimer II astrocytes usually proliferate. Diffuse astrocytic proliferation in the white matter and focal reaction in gray matter, which we ascribe to complicating factors, the foremost of which is anoxia, was found in many of the cases.

Ammonia↗
PubMed1988

Neuropathologic findings in progressive supranuclear palsy. A brief review with two additional case reports.

Recent studies utilizing electron microscopy and immunohistochemistry have added to the understanding of the pathology of progressive supranuclear palsy. This article reviews the neuropathologic findings of progressive supranuclear palsy and includes two new case reports. Findings in the patients reported here include extensive neuronal loss with reactive gliosis in deep subcortical gray matter such as globus pallidus, subthalamic nuclei, substantia nigra, red nucleus, dentate nucleus, and inferior olives. Neurofibrillary tangles were also noted in thalamus, hypothalamus, striatum, nucleus basalis, locus ceruleus, basis pontis nuclei, midbrain, pontine, and medullary reticular formation as well as in various cranial nerve nuclei.

Aged↗
PubMedDate not supplied

Effect of Apis mellifera propolis from two Brazilian regions on caries development in desalivated rats.

The purpose of the present study was to evaluate the effect of Apis mellifera propolis collected from two regions of Brazil on caries development in desalivated rats. Ethanolic extracts of propolis (EEP) were prepared from crude propolis samples collected in Minas Gerais state (MG), southeastern Brazil, and Rio Grande do Sul state (RS), southern Brazil. The flavonoid composition of EEP was analyzed by high-performance thin-layer chromatography (HPTLC) and reversed-phase high-performance liquid chromatography (HPLC). For the animal study, 30 specific pathogen-free Wistar rats were infected with Streptococcus sobrinus 6715 and surgically desalivated. The rats were randomly divided into three groups which were treated with 80% ethanol (control), EEP from MG and EEP from RS. The animals were placed in a König-Höfer programmed feeder and received 17 meals of diet 2000 daily at hourly intervals. The solutions were applied on the rat molars (25 microl on molars of each quadrant) twice a day, by using graduate syringes. After 3 weeks, the animals were killed by CO(2) asphyxiation. For microbial assessment, the left jaw was removed and sonicated in 154 mM NaCl solution. Dental caries was evaluated according to Larson's modification of Keyes' system. The HPTLC patterns and HPLC profiles demonstrated that both quality and quantity of flavonoid aglycones of EEP from MG were different compared to EEP from RS. In general, it is apparent that EEP from RS contained the highest concentrations of pinocembrin, chrysin, acacetin and galangin. The group of animals treated with EEP from RS showed the lowest smooth-surface and sulcal caries scores as well as less caries severity in smooth-surface and sulcal lesions, and these data were statistically different when compared with the control group. The group treated with EEP from MG only demonstrated a significant difference in the severity of sulcal lesions when compared to the control group. The percentage of S. sobrinus was lower in the groups treated with EEP, but did not differ statistically from the control group. The results showed that the cariostatic effect of propolis depends on its composition, and consequently the region of collection of propolis samples.

Analysis of Variance↗
PubMedDate not supplied

Effects of Apis mellifera propolis on the activities of streptococcal glucosyltransferases in solution and adsorbed onto saliva-coated hydroxyapatite.

Propolis, a resinous hive product collected by Apis mellifera bees, has been used for thousands of years in folk medicine. Ethanolic extracts of propolis (EEP) have been shown to inhibit the activity of a mixture of crude glucosyltransferase (Gtf) enzymes in solution. These enzymes synthesize glucans from sucrose, which are important for the formation of pathogenic dental plaque. In the present study, the effects of propolis from two different regions of Brazil on the activity of separate, purified Gtf enzymes in solution and on the surface of saliva-coated hydroxyapatite (sHA) beads were evaluated. The EEP from Minas Gerais (MG; Southeastern Brazil) and Rio Grande do Sul (RS; Southern Brazil) were tested for their ability to inhibit the enzymes GtfB (synthesis of insoluble glucan), GtfC (insoluble/soluble glucan) and GtfD (soluble glucan). The effects of propolis on Gtf from Streptococcus sanguis (soluble glucan synthesis) was also explored. The EEP from both regions effectively inhibited the activity of all Gtfs in solution (75-95%) and on the surface of sHA beads (45-95%) at concentrations between 0.75 and 3.0 mg of propolis/ml. However, the two samples of propolis showed different levels of inhibition on each of the enzymes tested. In general, EEP RS demonstrated a significantly higher inhibitory activity on GtfB and C activities (both solution and surface assays) than EEP MG at concentrations between 0.047 and 0.187 mg/ml (p<0.05). EEP MG, on the other hand, exhibited a greater inhibitory effect on the activities of surface GtfD (at 0.375, 0.75 and 1.5 mg/ml) and S. sanguis Gtf (at 1.5 and 3.0 mg/ml; p<0.05). These data indicate that EEP is a potent inhibitor of Gtf enzymes in solution and adsorbed on an experimental pellicle; however, its effect on Gtf activity is variable depending on the geographical origin of the propolis samples. There is a need to identify the active compounds of propolis.

Bacterial Proteins↗
PubMedDate not supplied

Interactions of Streptococcus mutans glucosyltransferase B with lysozyme in solution and on the surface of hydroxyapatite.

Several active enzymes have been identified as components of acquired enamel pellicle. In the present study, the interactions of Streptococcus mutans glucosyltransferase B (GtfB) with lysozyme in solution and on the surface of hydroxyapatite (HA) beads were studied. Experiments were also performed to investigate whether structural differences exist between glucans formed by GtfB enzyme in the presence or absence of lysozyme in solution and on the surface of HA. Hen egg-white lysozyme (HEWL) and saliva were used as the sources of lysozyme; lysozyme-depleted saliva was used as control. Lysozyme activity was significantly reduced when adsorbed onto HA beads compared with that in solution. The GtfB enzyme did not affect the activity of lysozyme in solution or that of adsorbed lysozyme onto HA. The presence of HEWL increased GtfB activity; bovine serum albumin had an even greater enhancing effect. Depletion of lysozyme from whole saliva increased GtfB activity in solution, but not on the surface of saliva-coated HA. The presence of lysozyme affected the amount of glucan formation by GtfB, but not the structure of glucans formed in solution and on the surface. Therefore, the interaction of lysozyme and GtfB enzymes on HA surface may modulate the formation of glucan and dental plaque.

Animals↗
PubMedDate not supplied

Determining the utility and effectiveness of the NeoPath AutoPap 300 QC System used routinely.

OBJECTIVE: To evaluate routine use of the NeoPath AutoPap 300 QC System (AP 300) as it influences diagnostic quality and operations in a large cytology laboratory. STUDY DESIGN: During a three-month period, 35,143 conventionally prepared consecutive cervical cytologic smears taken from non-high-risk women and evaluated as negative by our staff of 25 cytotechnologists were selected for processing by four AP 300 instruments. Slides flagged for review by the AP 300 were reevaluated by our five quality control (QC) cytotechnologists. False negative (FN) results were compared with results of our current practice (CP), random-selection QC method, used during the preceding six months. RESULTS: A 240% increase was seen in the FN detection rate for atypical squamous cells of undetermined significance (ASCUS) and squamous intraepithelial lesions (SIL) (n AP = 65 FN in 5,034 QC, n CP = 77 FN in 22,052 QC) and a 744% increase in the FN detection rate for low and high grade SIL (n AP = 24 FN/5,034 QC, n CP = 12 FN/22,052 QC). The rate of overcall by cytotechnologists did not increase. The QC ASCUS/SIL ratio improved. FN biopsy correlation increased from 45% to 85% (n CP = 17/38 agreement, n AP = 23/27 agreement). Turnaround time increased by one or more days for negative and 1.5 days for QC result reporting. Sensitivity varied among instruments. CONCLUSION: More FN results and greater specificity were seen using the AP 300 than using CP. As with other instrumentation, each laboratory should establish acceptable ranges of performance and baseline values for sensitivity and specificity.

Biopsy↗