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Biomedical subjects

K Lee

Publications and source records attributed to K Lee.

At least 973 records · Page 54Linked to original sources
PubMedDate not supplied

The development of two flanking SCAR markers linked to a sex determination locus in Salix viminalis L.

Most studies of sex determination systems in plants involve dioecious annuals that have known sex chromosomes. Despite the absence of such structures in the majority of dioecious plants, gender seems to be under relatively strict genetic control in some species. Genetic markers linked to a female sex-determination locus in Salix viminalis L. have been discovered through bulked segregant analysis of three full-sib families using approximately 1,000 arbitrary primers. Two RAPD markers that were present in the common female parent as well as in predominantly female progeny of these families were subsequently sequenced and converted to sequence characterized amplified region (SCAR) markers. The two SCAR markers are correlated with gender in the three full-sib families and are present in 96.4% of the female progeny and 2.2% of the males, providing evidence of linkage to a putative female-specific locus associated with gender determination in S. viminalis. Estimates of recombination suggest that the two markers are flanking a putative sex determination locus, SDL-II, in certain families of S. viminalis.

Genetic Markers↗
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Effect of shear rates on protein adsorption in the total artificial heart.

Plasma protein adsorption is the first event in blood-material interaction and influences subsequent platelet adhesion and thrombus formation. Thromboembolic events are strongly influenced by surface characteristics of materials and fluid dynamics inside the blood pump. In vitro flow visualization, and an animal experiment with a moving actuator total artificial heart (TAH), were performed to investigate fluid dynamic effects on protein adsorption. The different levels of shear rate inside the ventricle were determined by considering the direction of opening of the four heart valves in the implanted TAH, and the visualized flow patterns as well. Each ventricle of the explanted TAH was cut into 12 segments according to the shear rate level. The adsorbed protein on each segment was quantified using an ELISA method after soaking in 2% (w/v) SDS/PBS for 2 days. Adsorbed protein layer thicknesses were measured by the immunogold method under transmission electron microscopy. Scanning electron microscopic observation showed that the right ventricle, immobilized with albumin, displayed different degrees of platelet adhesion on each segment, whereas the left ventricle, coated with polythyleneoxide-sulfonate, indicated nearly the same platelet adhesion behavior, regardless of shear rates. The surface concentrations of adsorbed proteins in the low shear rate region are higher than those in the high shear region, which was confirmed statistically.

Adsorption↗
PubMedDate not supplied

Imaging characteristics of a small germanium camera.

A high purity germanium gamma-camera has been developed and is currently being evaluated. This camera incorporates unique performance parameters such as a 2 mm full-width spatial response function with rejection of multiple-scatter in the detector, a 2.2% FWHM energy resolution for 99 mTc, a 180 nsec paralyzable dead-time, and a 2 mu sec non-paralyzable dead-time. Imaging studies demonstrate the superior capabilities of this instrument.

Animals↗
PubMedDate not supplied

Serum lactate and base deficit suggest inadequate resuscitation of patients with burn injuries: application of a point-of-care laboratory instrument.

Urinary output of 30 to 50 ml/hr and mean arterial pressure of more than 70 mm Hg continue to be the yardsticks by which patients with burn injuries are resuscitated. We designed this prospective, descriptive study to compare these parameters with serial base deficit and serum lactate values, which have been found to be sensitive indicators of adequate fluid resuscitation in trauma patients. The sample group consisted of 53 patients, consecutively admitted to the burn intensive care unit, who had 15% or more total body surface area burns. No changes in resuscitation protocol were implemented. Within the 48-hour period after admission, 2 ml heparinized venous blood samples were collected and analyzed every 2 to 4 hours, and vital signs, urinary output, fluid type, and volume administered were documented each hour. Urinary output and mean arterial pressure were maintained at more than 30 ml/hr and more than 70 mm Hg, respectively. Partial correlations between the traditional resuscitation variables and serum lactate and base deficit were low. On average, serum lactate and base deficit remained abnormally high during the study period. These new parameters may be used to improve the fidelity with which burn shock resuscitation is undertaken. Further studies of these parameters and how they may be used as endpoints in fluid resuscitation are needed.

Acidosis↗
PubMedDate not supplied

A detailed experimental and theoretical comparison of the angular and energy dependencies of grid transmission.

Grid transmission characteristics have been predicted, with good agreement demonstrated between experiment and theory. Differences between the present work and an earlier theoretical analysis have been noted. It is shown that comparison between experiment and theory can lead to a sensitive method for determining grid parameters. Generally, the derived grid parameters deviate somewhat from manufacturer supplied data. Use of the manufacturer's nominal parameters can lead to large errors in predicting grid transmission.

Radiography↗
PubMedDate not supplied

Experimental and theoretical energy and angular dependencies of scattered radiation in the mammography energy range.

Predicted scatter characteristics from a Monte Carlo code have been compared to an experiment for a 4.0-cm-thick acrylic resin (Plexiglas) phantom and 27.3-keV radiation. The results show generally good agreement, except that in the scattered spectra the predictions appear to underestimate the proportion of photons in the low-energy tail of the scattered radiation. The angular dependency of the energy-integrated scattered radiation fluence is in excellent agreement with the predictions.

Mammography↗
PubMedDate not supplied

A technique for the evaluation of a missing tissue compensator system.

A two dimensional approach to the evaluation of a missing tissue compensator system has been developed and implemented. Quantitative descriptors of the dose area histograms generated by scanning films irradiated under a variety of compensated and uncompensated conditions are proposed. The method has been found to be useful during the acceptance testing of a commercial compensator system and the results of this exercise are presented.

Evaluation Studies as Topic↗
PubMedDate not supplied

Recurrence of bleeding in patients with hypertensive intracerebral hemorrhage.

To characterize the recurrence of bleeding in patients who had hypertensive intracerebral hemorrhage (HICH), the authors reviewed 989 patients who underwent treatment for HICH between 1989 and 1995. Fifty-three patients (5.4%) had two episodes of HICH within a median interval of 22.9 +/- 16.3 months (range 1.5-72 months), and of these 3 (5.7%) had three episodes of HICH. The recurrence of bleeding most commonly occurred within 2 years of the first hemorrhage: in 66% of the 53 patients the second hemorrhage occurred soon after the first (within 1 year in 34%, within 1-2 years in 32.1%). The site of the second hemorrhage was different from the initial site in all patients. Only 1 patient had a third hemorrhage in the same site as the second hemorrhage. The common patterns of recurrence were 'ganglionic (putamen/caudate nucleus)-thalamic' in 26.8% and 'ganglionic-ganglionic' in 21.4%. The 'lobar-lobar' pattern was noted in only 2 patients. The volume of the hematoma was increased at the second hemorrhage. The overall mortality was 28.3%. The risk of recurrent hemorrhage significantly increased in the patients who had antihypertensive therapy of less than 3 months after the initial attack compared to those with further long-term therapy (p < 0.005). Long-term regular control for hypertension is needed to prevent recurrent hemorrhage.

Adult↗
PubMedDate not supplied

Antrolithiasis in the frontal sinus.

A very rare case of sinusitis with antrolithiasis in the left frontal sinus of a 63-year-old male patient is reported. Various conservative treatments had no effect on the decrease of his left frontal pain and of postnasal drip. Neither bacteria nor fungus were detected in the discharge. Computed tomographic scanning revealed several high-dense spots in an isodense shadow in the left frontal sinus. At first, endoscopic sinus surgery (ESS) was employed and a stony mass was detected in the nasofrontal duct and sinus. Patency of the nasofrontal duct was insured and a sticky paste and small masses were removed as well as possible. However, the flow of discharge from the frontal duct continued after surgery. We performed a second operation with extranasal approach and additional stones in the sinus were successfully removed. Most cases of antrolithiasis are caused by a foreign body or caseous sinusitis with fungus. The maxillary sinus is the most common site of disease in antrolithiasis. It is unknown why the present case of antrolithiasis was in the frontal sinus. In such cases of antrolithiasis or cases having pastelike contents in the frontal sinuses, we conclude that ESS may be an unsuccessful treatment and a classical surgical approach may be required.

Endoscopy↗
PubMedDate not supplied

Nocardia keratitis after traumatic detachment of a laser in situ keratomileusis flap.

PURPOSE: Nocardia are gram-positive bacteria existing ubiquitously in the environment; they can cause keratitis. Nocardia asteroides keratitis occurred in the interface between the stromal bed and flap after traumatic detachment of the flap 4 months after an initially uncomplicated laser in situ keratomileusis (LASIK) procedure. METHODS: Nocardia asteroides keratitis was confirmed by culture. Therapy included topical and oral trimethoprim-sulfamethoxazole. RESULTS: Thirteen months after the trauma, the patient's spectacle-corrected visual acuity was 20/20 with a manifest refraction of -2.25 -1.00 x 30 degrees. CONCLUSIONS: The immediate steps of management consisting of surgically lifting the corneal flap, rapid microbial identification, and proper treatment with specific antibiotics resulted in the successful treatment of Nocardia asteroides keratitis in a traumatized eye after LASIK.

Adult↗
PubMedDate not supplied

Lithium therapy and disorders of the parathyroid glands.

OBJECTIVE: To review the effects of lithium (Li+) on the parathyroid glands. METHODS: We describe the incidence and clinical features of Li(+)-associated hyperparathyroidism and summarize the current state of knowledge of the in vitro and in vivo effects of Li+ on the parathyroid cell. RESULTS: Li+ treatment is known to increase the calcium set-point in the parathyroid glands for inhibition of parathyroid hormone secretion. Evidence suggests that this change in calcium set-point occurs as a result of Li+ interference with transmembrane signal transduction in the parathyroid cell. Li+ therapy may accentuate the set-point error in patients with primary hyperparathyroidism and unmask preexisting hyperplastic or adenomatous changes in the parathyroid glands. Li+ may also cause de novo hypercalcemia and hyperparathyroidism that are usually mild, clinically insignificant, and reversible with discontinuation of Li+ therapy. In some patients receiving long-term Li+ therapy, however, persistent hyperparathyroidism develops despite discontinuation of Li+ therapy, and it may be symptomatic and associated with serious organ system sequelae. Li(+)-associated hypercalcemia can be a challenging clinical dilemma in patients with bipolar affective disorder because of the lack of effective therapeutic alternatives, as well as the potential for Li(+)-induced hypercalcemia to exacerbate psychopathologic symptoms. CONCLUSION: Because severe hypercalcemia may occur as a result of toxic Li+ levels, Li+ and calcium levels should be monitored in patients on long-term Li+ therapy.

Journal Article↗
PubMedDate not supplied

Wind velocity effects on sampling rate of NO2 badge.

The effects of wind velocity on a sampling rate of a nitrogen dioxide (NO2) diffusive badge were experimentally determined using a turntable. The use of a turntable permits the collection of the large amounts of data that are needed for statistically reliable results at several wind velocities in one experiment. The regression model for the wind effect determined by these experiments was closely correlated with data previously gathered from experiments using wind tunnels. Experiments at two different relative humidities, 35% and 60%, were performed and analyzed by a simple least square regression model. A multi-regression model containing two independent variables, wind velocity and relative humidity, also was developed. The multi-regression model was useful at relative humidity between 20% and 60% and wind velocity between 0 and 7 meter per second (m/sec).

Air Pollutants↗
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Immunological properties of melanoma tumor-infiltrating lymphocytes before and after IL-2-based biotherapies.

Immunological properties of melanoma TILs before and/or after IL-2-based biotherapies were investigated. TILs harvested before therapies, including those for adoptive transfer, proliferated well in culture with IL-2 and displayed cytotoxicity relatively restricted to autologous tumor cells. In contrast, TILs during or at the end of IL-2 based therapies did not proliferate in culture with IL-2. TILs from tumors even harvested 45 days after the end of IL-2 therapy modestly proliferated in culture with IL-2 and showed MHC-nonrestricted cytotoxicity. The number of live tumor cells that were yielded from melanomas during or at the end of IL-2-based therapies significantly decreased in all nine patients with metastatic melanomas, regardless of their clinical responses (2 PR, 2 MR, 2 SD, and 3 PD). Collectively, these results suggest that current IL-2-based therapies resulted in both transient nonresponsiveness of TILs to IL-2 and transient decrease in the number of live tumour cells in most melanoma patients.

Cell Count↗
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Aneurysm precautions: a physiologic basis for minimizing rebleeding.

It has been noted that the primary goal in the management of a patient with a subarachnoid hemorrhage secondary to a ruptured intracranial aneurysm is to prevent a recurrent hemorrhage during those first 2 critical weeks. Because the aneurysm itself has lost the capability of autoregulation and thus cannot control blood volume or pressure, it is subject to rupture with the sudden increases in mean systemic pressure or decreases in venous return to the heart. Factors which increase blood pressure and reduce venous return have been discussed, and the various comments regarding nursing management have been made. One certainly realizes that these activities cannot be prevented entirely. However, the nurse should be aware of the potential danger to the patient of performing Valsalva maneuvers, of encouraging static contractions, and of exposure to noxious stimuli that induce an acute stress reaction, in addition to the other activities discussed herein. When planning care for the patient placed on aneurysm precautions, it should be stressed that although not all these activities are preventable, care should be taken to avoid performing more than one of them at a time. The nurse can assist the patient to the extent that these activities are minimized or prevented until such time as an operation is indicated or the vascular tissue repairs itself.

Cerebral Hemorrhage↗