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Biomedical subjects

B C Lee

Publications and source records attributed to B C Lee.

At least 91 records · Page 5Linked to original sources
PubMed1998

MRI of focal cortical dysplasia.

We studied nine cases of focal cortical dysplasia (FCD) by MRI, with surface-rendered 3D reconstructions. One case was also examined using single-voxel proton MR spectroscopy (MRS). The histological features were reviewed and correlated with the MRI findings. The gyri affected by FCD were enlarged and the signal of the cortex was slightly increased on T1-weighted images. The gray-white junction was indistinct. Signal from the subcortical white matter was decreased on T1- and increased on T2-weighted images in most cases. Contrast enhancement was seen in two cases. Proton MRS showed a spectrum identical to that of normal brain.

Cerebral Cortex↗
PubMed1998

Patency of infrainguinal polytetrafluoroethylene bypass grafts with distal interposition vein cuffs.

Polytetrafluoroethylene (PTFE) prosthetic bypasses in the lower extremity have poor patency rates, particularly in limb salvage cases. Patency and limb salvage rates of PTFE bypasses supplemented by distal interposition vein cuffs were assessed in patients requiring revascularization for critical limb ischemia, in the absence of a suitable autologous saphenous vein. Between October 1993 and April 1996, 163 patients underwent 185 infrainguinal bypasses. Forty-three limbs in 42 patients (12 women, 30 men; mean age 67 years) did not have a suitable autologous saphenous vein (24%) and had femoropopliteal (20) and infrapopliteal (23) bypasses performed. Patients were examined prospectively at 3-month intervals during the first year and at 6-month intervals thereafter to determine graft patency and limb salvage. Postoperative anticoagulation with warfarin was used in 26 patients. Indications for operation included limb salvage in 41 extremities (21 rest pain/ulceration or gangrene, 20 rest pain alone), and disabling claudication in two. Patients were followed clinically for 2-30 months (mean 10 months). Cumulative 2-year life-table patencies for all grafts, femoropopliteal and infrapopliteal bypasses were 64%, 75% and 62%, respectively. Previous primary patencies at the authors' institution for PTFE bypasses without vein cuffs were 35%, 46% and 12% for the same categories. Cumulative life-table limb salvage for all PTFE/vein cuff bypasses in the present series was 76% compared with 37% in previous PTFE bypasses without vein cuffs. Adjunctive use of distal interposition vein cuffs improves prosthetic graft patency, while producing satisfactory limb salvage. Postoperative anticoagulation did not influence graft patency. PTFE/vein cuff for lower-extremity revascularization shows good 2-year patency and is an acceptable alternate conduit in patients with critical limb ischemia when autologous saphenous vein is absent.

Aged↗
PubMed1998

Vertical strabismus resulting from an anomalous extraocular muscle.

Unusual ocular motility abnormalities have been rarely reported to result from anomalous extraocular structures. These structures, which may be either muscular or fibrotic, attach to the globe and produce a mechanical restriction resulting in incomitant strabismus. To our knowledge, we report the first patient with an anomalous extraocular muscle in whom the clinical, radiologic, surgical, and histopathologic findings are described.

Child, Preschool↗
PubMed1998

A model of coccidioidal meningoencephalitis and cerebrospinal vasculitis in the rabbit.

Coccidiodal meningitis is a devastating complication of disseminated coccidioidomycosis. An animal model of this infection could enhance understanding of the pathogenesis of the disease and lead to improvements in therapy. A rabbit model of central nervous system infection simulating human disease was established using a blind cisternal tap technique to inoculate 4 x 10(3)-1 x 10(6) arthroconidia of Coccidioides immitis into the cisterna magna. Systemic, neurologic, and histopathologic findings of meningitis were observed in all rabbits, but an inoculum of 2 x 10(4) arthroconidia produced a chronic illness in which meningeal endarteritis obliterans was consistently observed. Serial sampling of cerebrospinal fluid demonstrated an inflammatory response. Growth of C. immitis was demonstrated by quantitative fungal culture from brains and proximal spinal cords.

Animals↗
PubMed1998

Detection and assignment of proteins encoded by rice black streaked dwarf fijivirus S7, S8, S9 and S10.

The proteins encoded by rice black streaked dwarf fijivirus (RBSDV) genomic segments 7-10 (S7-S10) were characterized. Open reading frames (ORFs) from these segments were expressed as fusion proteins in Escherichia coli. Antibodies raised against the expressed products were used as probes to determine whether the viral ORFs encode structural proteins. In Western blots, antibodies to the expressed S8 and S10 products reacted with a core capsid (65 kDa) and a major outer capsid (56 kDa) protein, respectively, while none of the antibodies to S7 and S9 products reacted with structural proteins. Antisera to RBSDV S7 ORF1 and S9 ORF1 each detected a single protein of the predicted size in total protein extracts from infected rice plants and viruliferous Laodelphax striatellus. Immunoelectron microscopy revealed that antibodies to RBSDV S7 ORF1 and RBSDV S9 ORF1 reacted with tubular structures and viroplasm, respectively, in sections of both infected maize plants and viruliferous L. striatellus. Antisera to ORF2 of S7 and S9 failed to detect any proteins in the infected tissue using either Western blotting or immuno-electron microscopic techniques.

Amino Acid Sequence↗
PubMed1998

A Neisseria meningitidis fbpABC mutant is incapable of using nonheme iron for growth.

The neisserial fbpABC locus has been proposed to act as an iron-specific ABC transporter system. To confirm this assigned function, we constructed an fbpABC mutant in Neisseria meningitidis by insertional inactivation of fbpABC with a selectable antibiotic marker. The mutant was unable to use iron supplied from human transferrin, human lactoferrin, or iron chelates. However, the use of iron from heme and human hemoglobin was unimpaired. These results support the obligatory participation of fbpABC in neisserial periplasmic iron transport and do not indicate a role for this genetic locus in the heme iron pathway.

ATP-Binding Cassette Transporters↗
PubMed1998

Normal brain in human newborns: apparent diffusion coefficient and diffusion anisotropy measured by using diffusion tensor MR imaging.

PURPOSE: To establish quantitative standards for the directionally averaged water apparent diffusion coefficient (D) and quantitative diffusion anisotropy (A sigma) of normal brains in newborns by using diffusion tensor magnetic resonance (MR) imaging. MATERIALS AND METHODS: Diffusion tensor MR imaging was performed during the first 36 hours of life in 22 newborns (gestational age range, 31-41 weeks). Values of D and A sigma were measured in regions of interest chosen in the cortical gray matter, centrum semiovale, caudate nuclei, lentiform nuclei, thalami, internal capsules, and cerebellar hemispheres. RESULTS: The D values in the gray and white matter in newborns are considerably higher than those in adults. There is a striking correlation between gestational age and D, with D decreasing as gestational age increases. The A sigma values in the white matter in newborns are lower than those in adults. Values of A sigma show statistically significant correlations with gestational age only in the white matter of the centrum semiovale, in which A sigma values increase sharply near term. CONCLUSION: The D values primarily reflect overall brain water content. The A sigma values are more sensitive to tissue microstructure (e.g., white matter packing and myelination). The D and A sigma images reveal information and not apparent on T1- and T2-weighted images.

Adult↗
PubMed1998

Type A behavior and stroke: high tenseness dimension may be a risk factor for cerebral infarction.

Although type A behavior (TAB) has been shown to be related to coronary heart disease, the relationship between TAB and stroke was rarely investigated. We studied TAB in stroke patients with the use of the questionnaire developed by Eysenck and Fulker that has 4 subdimensions: Tenseness, Ambition, Activity, and Unrepressed. The questionnaire was administered to 224 patients with acute stroke and 100 controls. The patients were further classified as having cerebral infarction (large vessel infarction and small vessel infarction), and intracerebral hemorrhage. We found that, among the 4 subdimensions, only the Tenseness score was significantly higher in patients with cerebral infarction but not in those with intracerebral hemorrhage compared to the controls. On subgroup analysis, Tenseness score was higher in patients with large vessel infarction but not in those with small vessel infarction than in those with intracerebral hemorrhage or controls. The association of high Tenseness score with cerebral infarction (and large vessel infarction) remained significant after multiple logistic analysis adjusting various risk factors such as hypertension, diabetes mellitus, cigarette smoking and habitual alcohol drinking. Our data suggest that a high Tenseness dimension of TAB may be an independent risk factor for ischemic stroke, probably associated with atherogenesis.

Cerebral Infarction↗
PubMed1998

Central pathway of taste: clinical and MRI study.

We present 3 cases of hemiageusia due to focal ischemic lesions in the brainstem. Clinical presentation with discrete localization of these lesions suggests that the central taste pathway in humans projects ipsilaterally from the solitary nucleus up to the level of the upper pontine or lower midbrain before decussation. Associated partial sensory disturbance of the face or limb with lack of evidence of medial lemniscus decussation at the upper brainstem suggests that the medial lemniscus may not directly convey taste sensation.

Ageusia↗
PubMed1998

Cerebral sparganosis with intracerebral hemorrhage: a case report.

We describe the clinical case and radiologic findings in a woman with cerebral sparganosis in which intracerebral hemorrhage was the presenting feature with hemiparesis and dysarthria. CT demonstrated high-density lesions in the right frontoparietal area, suggesting a hematoma. With conservative management, hemiparesis improved and follow-up CT revealed what looked like a resolving hematoma. Two weeks later, she complained once again of aggravated left hemiparesis and facial weakness. Diagnosis of sparganosis was made on the basis of brain MRI and ELISA. Stereotactic surgery was performed, and a live larva of sparganum was successfully removed.

Animals↗
PubMed1997

SA-1, a nuclear protein encoded by one member of a novel gene family: molecular cloning and detection in hemopoietic organs.

We report the molecular cloning of a novel gene family. The first member of this family was cloned from a mouse lambda gt11 cDNA library using the B92 monoclonal antibody (mAb) raised against stromal cell extracts. This was followed by RACE-PCR using mRNA from the stromal cell line. A 4 kb cDNA was obtained encoding a unique protein sequence of 1258 aa, that we designate stromal antigen (SA)-1. The human SA-1 gene was cloned by homology from a thymus cDNA library and the sequence of the predicted protein was found to be highly homologous to the murine SA-1 (>98.9%). Another cDNA was cloned and the deduced protein (SA-2) was 71% homologous to SA-1. Northern blot and PCR analysis indicated that on the mRNA level the SA-1 gene is expressed in all tissues analyzed and probably encodes a single transcript. The identification of SA-1 protein in tissues and cells required combined immunoprecipitation and Western blotting using a polyclonal antiserum raised against a predicted peptide of SA-1 and the B92 mAb. Using this assay we identified a protein of about 120 kDa in hemopoietic organs. Subcellular fractionation indicated that SA-1 is a nuclear protein. Thus, despite the ubiquitous expression on the mRNA level, the protein was predominantly detected in hemopoietic organs and may therefore be controlled on a post-transcriptional level. The SA-1 gene described in this study is highly conserved between mouse and man. This implies a crucial function for this protein.

Amino Acid Sequence↗
PubMed1997

Changes in plasma levels of lipids and lipoprotein composition in patients with Kawasaki disease.

Studies on the response of plasma lipids and lipoproteins to Kawasaki disease are scarce so far. The purpose of this study was to investigate the changes in plasma levels of lipids and apolipoproteins as well as the composition of different lipoproteins in patients during the acute and convalescence phases of Kawasaki disease. The results showed that during the acute phase, the concentrations of plasma high density lipoprotein (HDL)-cholesterol, apolipoprotein A-I (apoA-I) and A-II (apoA-II) were significantly reduced. While the reduction of HDL-cholesterol was mainly related to the lowering of esterified and unesterified cholesterols in HDL2 during the acute stage of Kawasaki disease, most of which recovered during the subsequent convalescence phase. The plasma concentration of triglycerides was 46% higher in patients during the acute phase of Kawasaki disease than in the control subjects, which may be ascribed to the increase of triglycerides in very low density lipoprotein (VLDL), low density lipoprotein (LDL) and HDL2. The variables studied above did not appear to be independent parameters. The level of plasma apoA-I showed a stronger negative association with triglyceride concentration (r = -0.22) than apoA-II (r = -0.11) and HDL-cholesterol (r = -0.07). Furthermore, the levels of cholesterol, apoA-I and apoA-II in HDL2, but not in HDL3, were inversely correlated with the levels of triglyceride. We conclude that the temporary changes of lipid levels associated with Kawasaki disease results predominantly from alterations of lipoprotein composition.

Apolipoproteins↗
PubMed1997

MR imaging surface display of the cerebral cortex in children.

The purpose of this study was to introduce the use of three-dimensional (3D) surface MR imaging display for clinical use. Surface display was created using images acquired with T1 magnetization prepared rapid acquisition gradient echo (MPRAGE) in 24 cases of migrational defects, cortical dysplasia and prenatal asphyxia. Schizencephaly and cortical dysplasia were pathologically confirmed. The precise configurations of cortical abnormalities, and their relation to the adjacent gyri and sulci were demonstrated. The topography of schizencephalic clefts was clearly defined. The appearance of ulegyria was characteristic and it was sometimes possible to differentiate polymicrogyria from pachygyria.

Cerebral Cortex↗
PubMed1997

Carotid arterial trauma: assessment with the Glasgow Coma Scale (GCS) as a guide to surgical management.

Management of carotid arterial injuries associated with focal neurological deficit or altered state of consciousness (SCON) remains unresolved. Experience with these injuries in one particular hospital was reviewed and the Glasgow Coma Scale (GCS) utilized to assist with clinical stratification of these patients. A literature review was also conducted to better define indications for repair or ligation of carotid injuries. From 1978 to 1990, 34 patients with carotid arterial injuries were reviewed with reference to the GCS, focal deficit, hypotension, anatomic site and mechanism of injury. The literature from 1952 to 1993 was surveyed for carotid artery injuries (1316 patients). Outcome of treatment with or without repair was compared with pre-operative neurologic status. Thirty-four patients with injuries of the common (24) or internal (10) carotid arteries were managed with repair (68%), ligation (24%) or observation (9%). The SCON was normal in 18 patients; 16 patients (88%) underwent repair and all remained normal. All patients with GCS 9-14 regained a normal SCON after surgical repair, while 10 patients with GCS < 8 had repair (5), ligation (3), and non-operative management (2); five returned to normal, four died and one remained comatose. However, outcomes correlated poorly with management. Of 1316 patients cited in the surgical literature, patients with no deficit and patients with pre-operative deficits did significantly better after repair as compared with ligation (P<0.001). In comatose patients, management did not affect outcome. It is concluded that carotid arterial injuries should be repaired in patients with normal neurologic evaluation, focal pre-operative neurologic deficits and in patients with GCS > 9. Comatose patients with GCS < 8 do poorly regardless of management. The GCS provides an objective for stratification of patients with altered SCON who benefit from repair of carotid arterial injuries.

Adult↗
PubMed1997

Nuclear antigen expressed by proliferating cells.

We describe a novel mouse monoclonal antibody (PRA-72) that recognizes a nuclear antigen associated with cell proliferation. The monoclonal antibody stained the nuclei of logarithmically growing cultured stromal cells. The nuclear staining disappeared when these cells entered Gzero phase of the cell cycle. Western blot analysis revealed a nuclear protein which appeared as a doublet at 35-40 KD, which was undetectable in extracts from confluent cells. Immunocytological study of purified cell populations from various cell cycle phases revealed peripheral nuclear staining in all stages except mitosis, when the chromosomes were observed enveloped with the antigen. In co-cultures of quiescent stromal cells and proliferating hemopoietic precursors, only the latter showed nuclear staining by PRA-72 monoclonal antibody. Further indications for selective expression of the antigen by proliferating cells were found by an immunohistochemical study of various tissues including newborn mouse bone marrow and its surrounding connective tissue, mouse tongue epithelium, and human carcinoma of the colon. This antibody may, therefore, prove useful in the evaluation of human tumors.

Adenocarcinoma↗
PubMed1997

Factors influencing exposure of children to major hazards on family farms.

On family farms, parents are usually knowledgeable of high-risk activities, yet they allow their children to be active participants in (or bystanders to) hazardous work for reasons not well-documented. A two-phase descriptive study, based on the theory of planned behavior and using mail survey research methods, was carried out to understand factors that influence parents' decisions to expose children to major hazards on family farms. A representative sample of 1,255 Wisconsin dairy farm fathers provided data about factors that influence their decisions to expose children younger than 14 years to risks of injury. Multivariate analyses revealed that attitudes, subjective norms, and perceived control accounted for up to three-fourths of the variance in fathers' behavioral intentions. Fathers' attitudes were stronger predictors of behavioral intentions than subjective norms (i.e., perceived social pressure) or perceived control. Grandparents and mothers exerted a limited influence. Other groups, such as health care providers, 4-H, Future Farmers of America, and insurers, exerted only a modest influence on fathers' feelings of social pressure. Few demographic characteristics of the family or farm were predictive of fathers' intentions to expose children to hazards.

Agricultural Workers' Diseases↗