Biomedical subjects

C M Lee

Publications and source records attributed to C M Lee.

At least 37 records · Page 2Linked to original sources

PubMed2002

Comparative positions of kinetoplasts in Trypanosoma musculi and Trypanosoma lewisi during development in vitro.

The development of Trypanosoma musculi and Trypanosoma lewisi were studied in vitro in the presence of adherent splenic cells. Both parasites developed only when attached by their flagellar tips to adherent splenic cells. During the proliferation of T. musculi, the kinetoplast migrated towards the nucleus, and once in the vicinity of the nucleus, the nuclear division was triggered. The kinetoplast of T. lewisi did not migrate towards the nucleus, but remained at its original location. The nucleus and kinetoplast divided at the same time in both parasites, and parasites started dividing from their flagellar ends and T. musculi and T. lewisi daughter cells were formed within 48 h. The unavailability of the adherent splenic cells in vitro led the parasites to transform into round/oval nonviable forms.

Animals↗

PubMed2002

Structure-property relationship of cast Ti-Nb alloys.

The present work is a study of the microstructure, mechanical properties and corrosion behaviour of a series of binary Ti-Nb alloys with Nb contents up to 35 wt%, with emphasis placed on the structure-property relationship of the alloys. The results indicate that crystal structure and morphology of the Ti-Nb alloys are sensitive to the Nb content. The cast c.p. Ti has a hexagonal alpha phase with a lath type morphology. The alloys containing 15 wt% or less Nb are dominated by a hexagonal alpha' phase with an acicular, martensitic structure. When containing 17.5-25 wt% Nb, the alloys are primarily comprised of an orthorhombic alpha" phase. With 27.5 wt% Nb, metastable beta phase starts to be retained. With Nb contents higher than 30 wt%, the equi-axed beta phase is almost entirely retained. Small amounts of omega phase are detected in alloys containing 27.5 and 30 wt% Nb. Among all present alloys, Ti-10Nb and Ti-27.5Nb exhibit the highest strengths, while the alpha"-dominated (17.5 and 20Nb) and beta-dominated (> 30Nb) alloys have the lowest moduli. All Ti-Nb alloys show excellent corrosion resistance in Hank's solution at 37 degrees C. From the present data, the microhardness, bending strength and modulus of the various phases in Ti-Nb alloys are compared and tentatively summarized as follows: Microhardness: omega > alpha' > alpha" > beta > alpha (c.p. Ti) Bending strength: omega > alpha' > alpha" > beta > alpha (c.p. Ti) Bending modulus: omega > alpha (c.p. Ti) > alpha' > alpha" > beta

Corrosion↗

PubMed2002

Fatal hepatic failure after emergence of the hepatitis B virus mutant during lamivudine therapy in a patient with liver cirrhosis.

Lamivudine therapy for chronic hepatitis and decompensated liver cirrhosis related to the hepatitis B virus (HBV) resulted in improvement of liver function and inhibition of viral replication. Despite emergence of the HBV mutant, e-antigen seroconversion and improvement of liver function may be achieved with continuation of lamivudine therapy. Although hepatic decompensation has been reported in a few cases after the emergence of lamivudine-resistant mutants, fatal cases of non-transplant patients have only rarely been reported in the literature. Here, we describe a patient with HBV-related liver cirrhosis who died after a breakthrough infection with a lamivudine-resistant mutant. Hepatic failure and mortality developed after flare-up of severe hepatitis after 13 months of lamivudine treatment. Emergence of the HBV mutant with substitution of isoleucine for leucine at residue 426 (L4261) in combination with isoleucine for methionine at residue 550 (M5501) was observed at 10 and 13 months of treatment.

Base Sequence↗

PubMed2002

A retrospective study for the outcome of pulmonary resection in 49 patients with multidrug-resistant tuberculosis.

BACKGROUND: Outcome of treatment using only chemotherapy for multidrug-resistant tuberculosis is usually considered not to be satisfactory. The combination of chemotherapy with surgical treatment has been producing higher acid-fast bacilli (AFB) negative sputum conversion and longer survival rates. This treatment strategy may be the solution for patients with multidrug-resistant tuberculosis. MATERIALS AND METHODS: A retrospective review was performed of the medical records and laboratory findings of 49 patients with multidrug-resistant tuberculosis among 130 patients who underwent pulmonary resection for pulmonary tuberculosis between January 1995 and December 1999 at National Masan Tuberculosis Hospital, Korea. RESULTS: The mean number of drugs to which the patients were resistant was 4.5. Patients had a mean age of 35 years. Cavitary lesions on plain chest X-ray were shown in 43/49 patients (87.8%); 31 had positive sputum cultures preoperatively (63.3%). The surgical techniques used were as follows: 12 pneumonectomies, 28 lobectomies, seven lobectomies with segmentectomies or wedge resections, one wedge resection and one cavernoplasty. The AFB negative sputum conversion rate was 93.5% with continuous postoperative chemotherapy. There were no deaths after surgery. Postoperative complications that developed were six cases of air leakage over a week, one of postoperative bleeding and one of wound infection. CONCLUSIONS: This study demonstrated the effectiveness of pulmonary resection with postoperative chemotherapy in cases of multidrug-resistant tuberculosis. Although there are different ideas about indications for surgery and the length and content of postoperative drug regimens, pulmonary resection should be considered an effective measure in combination with chemotherapy for treatment of multidrug-resistant pulmonary tuberculosis.

Adult↗

PubMed2001

4-Hydroxy-6-oxo-6,7-dihydro-thieno[2,3-b] pyrimidine derivatives: synthesis and their biological evaluation for the glycine site acting on the N-methyl-D-aspartate (NMDA) receptor.

Bioisostere approach has been shown to be useful to augment potency or to modify certain physiological properties of a lead compound. Based upon well documented bioisosterism, an isosteric replacement of benzene ring of 4-hydroxy-2-quinolone compound (L-695902) with a thiophene moiety was carried out to prepare the title compounds, 4-hydroxy-6-oxo-6,7-dihydro-thieno[2,3-b] pyrimidines 15. The resulting bioisosteric compounds 15 were evaluated for their antagonistic activity (binding assay) for NMDA receptor glycine site.

Animals↗

PubMed2001

Cosolvent effects of alcohols on the Henry's law constant and aqueous solubility of tetrachloroethylene (PCE).

The effects of selected cosolvents ethyl alcohol (EtOH), isopropyl alcohol (IPA), and tertbutyl alcohol (TBA) on the Henry's law constant (H) of tetrachloroethylene (PCE) in aqueous solutions were investigated using the static headspace method. Alcohols in solution at a concentration around 20% and above acted as cosolvents increasing the aqueous solubility of PCE, which resulted in lower H values for PCE as compared to the value of H in deionized water. TBA, the most hydrophobic of the three alcohols, exhibited the strongest cosolvent effects, while EtOH had the weakest effects. A ln-linear relationship was observed between H and the volumetric fraction of alcohol added. Investigation of the solubilization of PCE in alcohol solutions confirmed the cosolvent trend observed for the three alcohols. A ln-ln relationship was observed between H and the enhanced solubility of PCE at a particular alcohol concentration. It was also observed that the value of H is a function of the enhanced solubility regardless of the type of cosolvent used. The results from this research further define the behavior of PCE in alcohol flooding solutions used in the remediation of PCE contaminated media.

2-Propanol↗

PubMed2001

Denitrification with acrylamide by pure culture of bacteria isolated from acrylonitrile-butadiene-styrene resin manufactured wastewater treatment system.

Acrylamide is widely used in industrial applications as cement binder and solidification agent. Due to its carcinogenicity and toxicity, discharge of acrylamide to the natural water and soil systems may lead to an adverse environmental impact on water quality and thus endanger public health and welfare. This study attempts to isolate and identify the denitrifying bacteria, which utilize acrylamide as the substrate from the acrylonitrile-butadiene-styrene resin manufactured wastewater treatment system. The performance of the denitrifying bacteria for treating different initial acrylamide concentrations was also investigated under aerobic and anaerobic conditions. The test results indicated that the Pseudomonas stutzeri could remove acrylamide at concentrations below 440 mg/l under aerobic conditions. The acrylic acid and ammonia intermediates were used as carbon and nitrogen sources, respectively. However, P. stutzeri did not show the capability of metabolizing acrylonitrile under aerobic conditions. Furthermore, the P. stutzeri could utilize both acrylamide and acrylic acid in the presence of nitrate (denitrification) and acrylamide could be removed completely from the wastewater.

Acrylamide↗

PubMed2001

Denitrification with acrylonitrile as a substrate using pure bacteria cultures isolated from acrylonitrile-butadiene-styrene wastewater.

This study attempted to isolate and identify the denitrifying bacteria that utilize acrylonitrile as a substrate from acrylonitrile-butadiene-styrene (ABS) resin wastewater. The performance of the denitrifying bacteria for treating different initial acrylonitrile concentrations was also investigated under anoxic conditions. The results showed that seven strains of denitrifying bacteria that can use acrylonitrile or acrylic acid as a substrate were isolated from the denitrification tank of a wastewater treatment plant in a ABS resin manufacturing plant and a lab-scale anoxic granular activated carbon-fluidized bed. The bacteria strains Acidovorax facilis B and Pseudomonas nautica could utilize acrylonitrile up to 279 mg/l as a substrate for denitrification. For complete nitrate removal, an adequate supply of acrylonitrile was necessary. Under the assumption that the acrylic acid would be completely removed, the removal of 1 mg/l nitrate by A. facilis B or P. nautica, about 0.64-0.74 mg/l acrylonitrile or 0.87-1 mg/l acrylic acid was needed. Because strains A. facilis B and P. nautica could utilize acrylonitrile for denitrification, they are expected to play an important role in the treatment of acrylonitrile in the wastewater treatment plant (denitrification and nitrification processes) and lab-scale granular activated carbon-fluidized bed.

Acrylates↗

PubMed2001

Assessment of the myocardial changes in heart transplant recipients without evident acute myocardial rejection by integrated backscatter: comparison with simultaneous dobutamine stress echocardiography and (201)thallium spect.

Cardiomyocyte hypertrophy and interstitial fibrin deposition develop in cardiac allografts and contribute to the functional changes of transplanted hearts. We hypothesized that integrated backscatter (IBS) can detect these myocardial changes. A total of 32 heart transplant recipients with either no or mild acute rejection (International Society of Heart and Lung Transplantation grade IA) were enrolled in this study. IBS data of myocardium were collected immediately before simultaneous dobutamine stress echocardiography (DSE) and (201)thallium imaging. Coronary angiography and endomyocardial biopsy were also performed. Coronary angiography showed diffuse narrowing in 1 patient who also had abnormal results of IBS, DSE, and thallium results. In the other 31 patients with patent coronary arteries, there were 3 patients (10%) with abnormal DSE results, 19 patients (61%) with abnormal IBS patterns, and 16 patients (52%) with reversible thallium perfusion defects. Of the patients, 44% had cardiomyocyte hypertrophy and 56% interstitial fibrin deposition. There were significant differences in the prevalence of (201)thallium perfusion defects and serum cyclosporine levels between patients with and without abnormal IBS patterns. Pathologic changes were also associated with abnormal IBS patterns (p = 0.01). However, there was no association between abnormal IBS and DSE results. By multiple logistic regression analysis, the abnormal IBS patterns were associated inversely with serum cyclosporine level (p = 0.028). In conclusion, abnormal IBS patterns are associated significantly with perfusion heterogeneity and pathologic changes in heart transplant recipients without evident acute myocardial rejection. There is no association between abnormal IBS patterns and dobutamine-induced dyssynergy in these patients. IBS provides a noninvasive approach for detection of myocardial changes in transplanted hearts without evident acute rejection.

Cardiac Catheterization↗

PubMed2001

Inhibitory action of water soluble fraction of Terminalia chebula on systemic and local anaphylaxis.

We investigated the effects of the water soluble fraction of Terminalia chebula (Combretaceae) (WFTC) on systemic and local anaphylaxis. WFTC administered 1h before compound 48/80 injection inhibited compound 48/80-induced anaphylactic shock 100% with doses of 0.01-1.0 g/kg. When WFTC was administered 5 or 10 min after compound 48/80 injection, the mortality also decreased in a dose-dependent manner. Passive cutaneous anaphylaxis was inhibited by 63.5+/-7.8% by oral administration of WFTC (1.0 g/kg). When WFTC was pretreated at concentrations ranging from 0.005 to 1.0 g/kg, the serum histamine levels were reduced in a dose-dependent manner. WFTC (0.01-1.0 mg/ml) also significantly inhibited histamine release from rat peritoneal mast cells (RPMC) by compound 48/80. However, WFTC (1.0 mg/ml) had a significant increasing effect on anti-dinitrophenyl IgE-induced tumor necrosis factor-alpha production from RPMC. These results indicate that WFTC may possess a strong antianaphylactic action.

Anaphylaxis↗

PubMed2001

Hepatitis C virus infection among teenagers in an endemic township in Taiwan: epidemiological and clinical follow-up studies.

The aim of the study was to elucidate the epidemiological features of Hepatitis C virus (HCV) infection among teenagers in an endemic area by conducting a mass screening study. We also investigated the clinical outcome of the anti-HCV-positive subjects by conducting subsequent short-term and long-term follow-up studies. All 2837 students of two junior middle schools in Tzukuan, aged 13-16 years, were invited to be screened for anti-HCV, HBsAg, AST and ALT in October 1995. A total of 2726 (96%) students responded. Anti-HCV, HCV RNA and aminotransferase levels were evaluated among anti-HCV-positive students 1 month and 30 months later, respectively. A total of 38 (1.4%; M/F = 22/16) participants were anti-HCV-positive. The anti-HCV-positive students had higher rates of exposures to transfusion, anti-HCV-positive families and surgery. The prevalence (2.8%) of the 7 maritime villages was markedly higher than that (0.7%) of the other 8 villages (P < 0.001). Subsequent follow-up studies demonstrated that there might be 5 cases of acute or recent HCV infection, and 6 cases who had recovered from chronic HCV infection.

Adolescent↗

PubMed2001

Extended lamivudine treatment in patients with chronic hepatitis B enhances hepatitis B e antigen seroconversion rates: results after 3 years of therapy.

A study in Chinese patients with chronic hepatitis B showed that treatment with lamivudine for 1 year significantly improves liver histology and enhances hepatitis B e antigen (HBeAg) seroconversion compared with placebo. Fifty-eight patients from this 1-year study have received long-term treatment with lamivudine 100 mg; the outcome of 3 years of lamivudine is reported here. Before treatment, all patients had detectable HBeAg. HBeAg seroconversion (HBeAg-negative, anti-HBe-positive), hepatitis B virus (HBV)-DNA suppression, alanine transaminase (ALT) normalization, emergence of YMDD variant HBV, liver histology, and long-term safety were assessed. After 3 years of continuous treatment with lamivudine 100 mg daily, 40% (23 of 58) of patients achieved HBeAg seroconversion. In patients with baseline serum ALT >2 x upper limit of normal (ULN), the rate of HBeAg seroconversion was 65% (17 of 26). Median serum HBV-DNA concentrations were below the level of detection, and median ALT concentrations were within the normal range throughout 3 years of treatment. YMDD variant HBV emerged in 33 of 58 (57%) patients during the 3 years, of whom 9 (27%) achieved HBeAg seroconversion (6 after emergence of YMDD variant HBV). ALT levels and histologic scores after emergence of YMDD variant HBV did not show major deterioration. Lamivudine was well tolerated during 3 years of therapy. In conclusion, these data in Chinese patients with chronic hepatitis B show enhanced seroconversion rates with extended lamivudine treatment. Up to two thirds of patients with moderately elevated pretreatment ALT achieved HBeAg seroconversion after 3 years of therapy.

Adolescent↗

PubMed2001

Modification of forearm vascular function following short-term handgrip exercise training.

This study examined the effect of low (25% of maximum voluntary contraction) and high (75% of maximum voluntary contraction) intensity short-term handgrip exercise training on localized vascular function. Forearm blood flow was evaluated in twenty-eight healthy men (age: 23 +/- 4.3) pre- and post-training in both forearms at rest, following forearm occlusion and following forearm occlusion combined with handgrip exercise using strain gauge plethysmography. The 4-week program consisted of non-dominant handgrip exercise performed 5 d/wk for 20 min at either low or high intensity. Following training a significant increase in forearm blood flow was noted for the nondominant arm in both groups after forearm occlusion (low intensity group: 16.51%; high intensity group: 20.72%; p = 0.001) and forearm occlusion combined with handgrip exercise (low intensity group: 17.71%; high intensity group: 29.27%; p = 0.001). No significant group by test interaction (p = 0.632) was found. These data show improved unilateral vasodilatory responsiveness after short-term handgrip training. In addition, the degree of change is most notable following the greatest vasodilatory stimulus. Lastly, a lack of group by treatment interaction suggests the change may be independent of training stimulus.

Adult↗

PubMed2001

Long-term outcomes after ARDS.

Early reports of late outcomes among survivors of ARDS indicated that most patients improved dramatically after their intensive care unit stay, and few lived with residua of their once-severe pulmonary injury. Over the last decade, a collection of new studies with improved methodology and novel questions has improved our understanding of life after ARDS. After reviewing these newer investigations in the context of previously published literature, we have drawn several preliminary conclusions: (1) Long-term survival after hospital discharge is unaffected by ARDS, but is strongly affected by ARDS risk factor and comorbidities. (2) Respiratory symptoms after ARDS are more prevalent than previously indicated, but improve over the first 12 months of recovery. (3) Pulmonary function testing reveals marked impairment soon after ARDS. There is improvement over the first 6 months, with lingering mild decreases in lung volume and diffusing capacity in most patients. A small group of patients have severe impairment without improvement. (4) Quality of life, functional independence, and cognitive function are severely affected by ARDS, with dramatic improvement over the first year. Quality of life is lower than in matched critically ill controls. (5) Significant numbers of ARDS survivors suffer from posttraumatic stress syndrome. This is an exciting time for research in long-term outcomes of ARDS, with potential for future studies that validate these single-center hypotheses, explore their ramifications, and investigate the impacts of changing practices in the intensive care unit in the acute phase of ARDS.

Journal Article↗

PubMed2001

Sustainable soil management practices and quality of potato grown on erodible lands.

Land productivity can decline when top soil is lost. In Kentucky, limited resource farmers often produce vegetable crops on erodible lands. The objectives of this study were 1) to quantify the impact of three soil management practices (SMPs) on quantity of potato produced on erodible land, 2) to evaluate the impact of pyrethrin and azadirachtin insecticides on potato tuber quality, and 3) to assess the impact of yard waste compost on the chemical composition (ascorbic acid, free sugars, phenol contents) of potato tubers. Potatoes (Solanum tuberosum L. cv. Kennebec) were grown in a silty loam soil of 10% slope. Plots (n= 18) were 3.7 m wide and 22 m long (10% slope), with metal borders of 20 cm above ground level. Two botanical insecticides, Multi-Purpose Insecticide (containing pyrethrin 0.2%) and Neemix 4EC (containing 0.25% azadirachtin) were sprayed twice on potato foliage during each of two growing seasons (1997 and 1999) at the recommended rates of 6 lbs and 2 gallons.acre(-1), respectively. The SMPs were tall fescue strips (FS) intercropped between each two potato rows, soil mixed with yard waste compost (COM) and no-mulch (NM) treatment (roto-tilled bare soil). The experimental designwas a 2 x 3 x 3 factorial with main factors of two insecticides and three SMPs replicated three times. Average potato yield was lowest in NM and FS and highest in COM treatments. Yield obtained from the bottom of the plots was greater than that obtained from the top of plots. Tuber defects (rot, scab, sun green, hollow heart, necrosis, and vascular discoloration) were significantly different between the two growing seasons. The two insecticidal treatments did not have much influence on potato yield or tuber defects. Tubers obtained from tall fescue treatments had low levels of ascorbic acid and reducing sugars compared to compost treatments.

Insecticides↗

PubMed2001

Aspiration of an oropharyngeal airway during nasotracheal intubation.

The oropharyngeal airway (OPA) has been a remarkably safe device since its invention by Guedel in 1933. This plastic device is easily placed in the mouth and used for aiding in mask ventilation. We report a case of the aspiration of an OPA causing near total upper airway obstruction.

Adult↗

PubMed2001

Influence of head-down and lateral decubitus neck flexion on heart rate variability.

The purpose of this study was to examine the response of heart rate variability (HRV), a noninvasive index of autonomic control, to head-down neck flexion (HDNF), which engages both otoliths and neck muscle afferents, and to lateral decubitus neck flexion (LNF), in which neck afferents are activated, whereas otolith afferent input is not. HRV and forearm blood flow were evaluated in participants lying prone, during HDNF, lying in the lateral decubitus position, and during LNF. Compared with the prone position, HDNF resulted in lower high-frequency (46.9 +/- 7.1 vs. 62.3 +/- 6.2) and higher low-frequency (53.1 +/- 7.1 vs. 37.7 +/- 6.2) power, expressed as normalized units, along with higher low-frequency-to-high-frequency ratio (1.65 +/- 0.3 vs. 0.78 +/- 0.2), whereas LNF resulted in no alterations in HRV indexes. Furthermore, there were no significant differences in forearm blood flow or vascular resistance among any of the positions. Our data suggest that otolith organs influence autonomic modulation of the heart, supporting previous studies reporting that HDNF elicits increased sympathetic outflow. These data further suggest that HDNF results in a parasympathetic withdrawal from the heart in addition to sympathetic activation.

Adult↗

PubMed2001

Flash echo gray scale imaging with subtraction in assessment of small hepatocellular carcinoma treated with percutaneous ethanol injection: preliminary report.

OBJECTIVE: To assess the therapeutic effect of percutaneous ethanol injection on small hepatocellular carcinoma by using a flash echo imaging system, a newly developed technique for detecting echoes from microbubble contrast agents more efficiently. METHODS: Six patients with 7 small nodular hepatocellular carcinomas, proved by fine-needle aspiration cytologic or pathologic examination, were included. Percutaneous ethanol injection was performed until there was no intratumoral color signal on conventional color and power Doppler ultrasonography. A bubble contrast agent was then injected, and flash echo imaging in the subtraction mode was performed for assessment of the therapeutic effect. Dynamic computed tomography, magnetic resonance imaging, and hepatic angiography were also used for evaluation of the therapeutic effect. RESULTS: Five tumors had perfusion defects that were equal in size to or larger than the tumors. No tumor stain was shown on hepatic angiography. Two tumors had partial perfusion defects. Viable tumors were confirmed by tumor resection in 1 case and cytologic examination in the other. CONCLUSIONS: Our preliminary results show that flash echo imaging with subtraction has potential value in evaluation of the therapeutic effect of percutaneous ethanol injection on small hepatocellular carcinoma.

Adult↗