Biomedical subjects

M Lee

Publications and source records attributed to M Lee.

At least 253 records · Page 14Linked to original sources

PubMed2000

Accuracy of cyclosporin measurements made in capillary blood samples obtained by skin puncture.

International consensus guidelines suggest that cyclosporin should be measured in whole blood. In some instances it may be advantageous to collect capillary blood, by a finger or ear prick method. However, drug concentrations in skin-puncture blood may not necessarily correlate with those measured in venous blood. This study compared cyclosporin concentrations in blood collected from the fingertip or earlobe with blood collected by standard venipuncture. Patient preference for each of the blood collection methods was also assessed. Specimens were obtained from organ transplant patients receiving cyclosporin, using each of the three methods: venipuncture, finger prick, and earlobe prick. The samples were assayed using a specific radioimmunoassay and the results were compared. In the 102 sets of samples collected, the mean difference (+/- standard deviation) in cyclosporin concentration between finger prick and venipuncture and ear prick and venipuncture was 2.6% (+/- 9.5%) and 2.7% (+/- 12.1%), respectively, while the comparable median (IQR) differences were 1.9% (-3.4% to +6.6%) and -1.1% (-2.8% to +7.2%), respectively. A high degree of correlation was observed between finger prick and venipuncture or ear prick and venipuncture or ear prick and finger prick (r2 > 0.86). Of the three methods of blood collection, finger prick was the patients' preferred method (P < 0.01). These data suggest that capillary blood collected by skin puncture is suitable for use in cyclosporin blood monitoring and acceptable to patients.

Area Under Curve↗

PubMed2000

Mechanisms of chloride secretion induced by thermostable direct haemolysin of Vibrio parahaemolyticus in human colonic tissue and a human intestinal epithelial cell line.

Thermostable direct haemolysin (TDH) produced by Vibrio parahaemolyticus is thought to play an important role in the severe diarrhoea caused by this organism. This study investigated the enterotoxicity of TDH for human intestinal cells. Addition of TDH to the mucosal side of human colonic tissue in Ussing chambers caused increased short circuit currents (Isc), a process that was inhibited by 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS), an inhibitor of Ca2+ -activated chloride (Cl-) channels. With human colonic epithelial (Caco-2) cells, high Isc and intracellular Ca2+ concentrations ([Ca2+]in) were detected after the addition of TDH to the apical side of the cell monolayer. The Isc decreased with the addition of DIDS, but not with glybenclamide, 5-nitro-2-(3-phenylpropylamino) benzoic acid, or gadolinium chloride. No Isc increase with TDH was observed when the Cl- in the medium was replaced by gluconate or when Ca2+ was depleted. Similarly, TDH did not raise [Ca2+]in after depletion of extracellular Ca2+. R7, a mutant form of TDH, reduced the effects of TDH on Isc and [Ca2+]in, as did protein kinase C (PKC) inhibitors. Thus, TDH increases Cl- secretion in human colonic epithelial cells, apparently through mechanisms involving cell binding and Ca2+ influx, followed by elevation of [Ca2+]in associated with PKC phosphorylation.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

PubMed2000

Appropriateness of the decision to transfer nursing facility residents to the hospital.

OBJECTIVES: To develop and test a standardized instrument, the purpose of which is to assess (1) whether skilled nursing facilities (SNFs) transfer residents to emergency departments (ED) inappropriately, (2) whether residents are admitted to hospitals inappropriately, (3) and factors associated with inappropriate transfers. DESIGN: A structured implicit review (SIR) of medical records. SETTING AND PARTICIPANTS: Using nested random sampling in eight community SNFs, we identified SNF and hospital records of 100 unscheduled transfers to one of 10 hospitals. MEASUREMENTS: Seven trained physician reviewers assessed appropriateness using a SIR form designed for this study (2 independent reviews per record, 200 total reviews). We measured interrater reliability with kappa statistics and used bivariate analysis to identify factors associated with assessment that transfer was inappropriate. RESULTS: In 36% of ED transfers and 40% of hospital admissions, both reviewers agreed that transfer/admit was inappropriate, meaning the resident could have been cared for safely at a lower level of care. Agreement was high for both ED (percent agreement 84%, kappa .678) and hospital (percent agreement 89%, kappa .779). When advance directives were considered, both reviewers rated 44% of ED transfers and 45% of admissions inappropriate. Factors associated with inappropriateness included the perceptions that: (1) poor quality of care contributed to transfer need, (2) needed services would typically be available in outpatient settings, and (3) the chief complaint did not warrant hospitalization. CONCLUSIONS: Inappropriate transfers are a potentially large problem. Some inappropriate transfers may be associated with poor quality of care in SNFs. This study demonstrates that structured implicit review meets criteria for reliable assessment of inappropriate transfer rates. Structured implicit review may be a valuable tool for identifying inappropriate transfers from SNFs to EDs and hospitals.

Advance Directives↗

PubMed2000

Experience with a higher impedance, fixed helix, steroid-eluting pacing lead. The SWEET PICOTIP Rx Study Group.

A higher impedance, steroid-eluting pacing lead was studied in a multicenter trial. A total of 132 leads were implanted in 61 patients and the electrical characteristics were compared with historical controls. The study lead had a lower pacing threshold at 3 months, 0.72 +/- 0.33 versus 1.29 +/- 0.82 in the atrium and 0.71 +/- 0.25 versus 1.52 +/- 0.52 in the ventricle (P < 0.01 for both). Impedance was significantly higher in the study lead, 923 +/- 133 versus 719 +/- 109 in the atrium and 980 +/- 235 versus 664 +/- 104 in the ventricle (P < 0.01 for both). Sensing was similar for both leads. The study lead's higher impedance values and low pacing thresholds combine to reduce pacing system energy requirements.

Aged↗

PubMed2000

Isolation and characterization of tetracycline-resistant clinical isolates of Helicobacter pylori.

Tetracycline is an important component of combination therapies for Helicobacter pylori eradication. Twenty-nine tetracycline-resistant isolates requiring MICs ranging from 4 to 16 microgram/ml were isolated from Korean (22 of 460) and Japanese (7 of 105) patients. Interestingly, all of the 29 tetracycline-resistant isolates exhibited cross-resistance to metronidazole, and the cross-resistance was transferred to tetracycline-sensitive H. pylori strains.

Drug Resistance, Multiple↗

PubMed2000

Apoptosis of primary-culture rat microglial cells induced by pathogenic Acanthamoeba spp.

To determine whether trophozoites and lysates of pathogenic Acanthamoeba spp. induce apoptosis in primary-culture microglial cells, transmission electron microscopic (TEM) examinations, assessment of DNA fragmentation by agarose gel electrophoresis, and the TdT-mediated dUTP nick-end labeling assay were performed. When a trophozoite of pathogenic Acanthamoeba culbertsoni came in contact with a microglial cell, the digipodium was observed by TEM. Nuclear chromatin condensation was observed in 10% of microglial cells, while it was not revealed when they were cocultured with weakly pathogenic Acanthamoeba royreba trophozoites. DNA fragmentation in microglial cells cocultured with the A. culbertsoni lysate was detected by electrophoresis, showing DNA ladder formation, whereas it was hardly observed in microglial cells cocultured with A. royreba. DNA fragmentation of microglial cells was also confirmed by flow cytometry analysis. The fluorescence of TdT-stained apoptotic bodies became intensely visible with microglial cells cocultured with the A. culbertsoni lysate. In contrast, with microglial cells cocultured with the A. royreba lysate, only a background level of fluorescence of TdT-stained apoptotic bodies was detected. These results suggest that some rat microglial cells cocultured with pathogenic A. culbertsoni undergo cytopathic changes which show the characteristics of the apoptotic process, such as nuclear condensation and DNA fragmentation.

Acanthamoeba↗

PubMed2000

Construction and characterization of murine cytomegaloviruses that contain transposon insertions at open reading frames m09 and M83.

A transposon derived from Escherichia coli Tn3 was introduced into the genome of murine cytomegalovirus (MCMV) to generate a pool of viral mutants, including two recombinant viruses that contained the transposon sequence within open reading frames m09 and M83. Our studies provide the first direct evidence to suggest that m09 is not essential for viral replication in mouse NIH 3T3 cells. Studies in cultured cells and in both BALB/c-Byj and CB17 severe combined immunodeficient (SCID) mice indicated that the transposon insertion is stable during viral propagation both in vitro and in vivo. Moreover, the virus that contained the insertion mutation in m09 exhibited a titer similar to that of the wild-type virus in the salivary glands, lungs, livers, spleens, and kidneys of both the BALB/c and SCID mice and was as virulent as the wild-type virus in killing the SCID mice when these animals were intraperitoneally infected with these viruses. These results suggest that m09 is dispensable for viral growth in these organs and that the presence of the transposon sequence in the viral genome does not significantly affect viral replication in vivo. In contrast, the virus that contained the insertion mutation in M83 exhibited a titer of at least 60-fold lower than that of the wild-type virus in the organs of the SCID mice and was attenuated in killing the SCID mice. These results demonstrate the utility of using the Tn3-based system as a mutagenesis approach for studying the function of MCMV genes in both immunocompetent and immunodeficient animals.

Animals↗

PubMed2000

Murine cytomegalovirus containing a mutation at open reading frame M37 is severely attenuated in growth and virulence in vivo.

A pool of murine cytomegalovirus (MCMV) mutants was generated by using a Tn3-based transposon mutagenesis procedure. One of the mutants, RvM37, which contained the transposon sequence at open reading frame M37, was characterized both in tissue culture and in immunocompetent BALB/c and immunodeficient SCID mice. Our results provide the first direct evidence to suggest that M37 is not essential for viral replication in vitro in NIH 3T3 cells. Compared to the wild-type strain and a rescued virus that restored the M37 region, the viral mutant was severely attenuated in growth in both BALB/c and SCID mice after intraperitoneal infection. Specifically, titers of the Smith strain and rescued virus in the salivary glands, lungs, spleens, livers, and kidneys of the SCID mice at 21 days postinfection were about 5 x 10(5), 2 x 10(5), 5 x 10(4), 5 x 10(3), and 1 x 10(4) PFU/ml of organ homogenate, respectively; in contrast, titers of RvM37 in these organs were less than 10(2) PFU/ml of organ homogenate. Moreover, the virulence of the mutant virus appeared to be significantly attenuated because none of the SCID mice infected with RvM37 had died by 120 days postinfection, while all animals infected with the wild-type and rescued viruses had died by 26 days postinfection. Our results suggest that M37 probably encodes a virulence factor and is required for MCMV virulence in SCID mice and for optimal viral growth in vivo.

3T3 Cells↗

PubMed2000

The efficacy of pentoxifylline as an anti-inflammatory agent in experimental Escherichia coli meningitis in the newborn piglet.

This study was done to evaluate the anti-inflammatory effect and the ensuing neuroprotective effect of pentoxifylline in neonatal experimental bacterial meningitis. Newborn piglets were divided into three groups: 10 in the control group (CG), 13 in the meningitis group (MG), and 13 in the meningitis with pentoxifylline group (PG). Meningitis was induced by intracisternal injection of 10(8) colony-forming units of Escherichia coli in 100 microl of saline. In PG, 20 mg/kg of pentoxifylline was given as a bolus intravenous injection 30 min before induction of meningitis and 6 mg/kg/h was given continuously throughout the experiment. In PG, the increase of CSF TNF-alpha level observed in MG was abolished. Reduced brain glucose and ATP concentrations observed in MG were significantly increased in PG. However, other parameters of inflammatory responses such as increased intracranial pressure, reduced glucose and increased lactate concentrations in the CSF observed in MG were not significantly down-modulated. The extent of CSF leukocytosis was even higher in PG than in MG. Increased cerebral cortical cell membrane lipid peroxidation products and decreased Na(+),K(+)-ATPase activity observed in MG, indicative of meningitis-induced brain cell membrane dysfunction, tended to improve without statistical significance in PG. In summary, although some anti-inflammatory effects have been observed, the overall anti-inflammatory effects of pentoxifylline was very weak, and it failed to significantly reduce the brain damage in experimental neonatal bacterial meningitis.

Animals↗

PubMed2000

Trampoline injuries of the cervical spine.

Trampolines were responsible for over 6,500 pediatric cervical spine injuries in 1998. This represents a five-fold increase in just 10 years. While most have been minor, paraplegia, quadriplegia and death are all reported. We present 2 cases of trampoline-related cervical spine injury and review the relevant literature. Additionally, we examine the efforts made to reduce the incidence of trampoline injuries, and discuss why these have failed. We conclude that safety guidelines and warnings are inadequate. In addition, we support recommendations for a ban on the use of trampolines by children.

Athletic Injuries↗

PubMed2000

Intracranial fibrosarcoma arising 5 years after chemotherapy alone for glioblastoma multiforme in a child.

We present a child diagnosed with glioblastoma multiforme during infancy and successfully treated with the 'eight-in-one' chemotherapy regimen, who developed an intracranial fibrosarcoma 5 years later. After resection of the fibrosarcoma, she received cranial radiation therapy and high dose chemotherapy with bone marrow transplant. She remains alive and recurrence-free 7 years following the diagnosis of her second intracranial malignancy.

Bone Marrow Transplantation↗

PubMed2000

In vitro inhibitory effect of some flavonoids on rotavirus infectivity.

The inhibitory effects of some flavonoids on the infectivity of rotavirus, which predominantly causes sporadic diarrhea in infants and young children, were investigated. Among tested flavonoids, diosmin and hesperidin had the most potent inhibitory activity on rotavirus infection. The fifty percent inhibitory concentration of both compounds was 10 microM. However, their aglycones did not have the inhibitory activity. The rutinose moiety of flavonoids should protect against the invasion of rotavirus into cells.

Animals↗

PubMed2000

Development of a web-based picture archiving and communication system using satellite data communication.

Using the JAVA language we have developed a Web-based picture archiving and communication system (PACS) which allows a remote hospital to access medical images. An asymmetric satellite data communication system (ASDCS) provided a receive-only link for data delivery and a conventional terrestrial link (which could be the conventional telephone network) allowed data transmission. The satellite communication link was 10-30 times faster than the conventional terrestrial link. To increase image transmission speeds over the Internet connection, JPEG and wavelet compression methods were used. The resulting images were evaluated quantitatively by measuring the peak signal:noise ratio and qualitatively by radiologists. Compression ratios of 10:1 or less were deemed acceptable for diagnostic purposes. The system appears to be suitable for teleradiology and telemedicine.

Computer Communication Networks↗

PubMed2000

Induction of osteopontin gene expression during mammary gland involution and effects of glucocorticoid on its expression in mammary epithelial cells.

To understand the molecular mechanisms of mammary gland involution, an involution-induced clone was identified from a cDNA library of mouse mammary gland by differential screening. Characterization of a clone by sequencing and northern analysis showed that expression of the osteopontin gene was induced during involution of mouse mammary gland. But induction of the osteopontin gene was not observed in apoptotic HC11 mammary epithelial cells under serum starvation. In HC11 cells, dexamethasone treatment from the seeding stage showed five-fold induction of osteopontin gene expression, but the expression was not changed when dexamethasone was added to confluent cells.

Animals↗

PubMed2000

Tamsulosin for the treatment of benign prostatic hypertrophy.

OBJECTIVE: To review the information necessary to assess the efficacy and safety of tamsulosin compared with other adrenergic antagonists for treatment of symptomatic benign prostatic hyperplasia. DATA SOURCES: A search was conducted of Cumulated Index Medicus, January 1993-August 1999, which was restricted to human trials and English-language journals. STUDY SELECTION AND DATA EXTRACTION: Efficacy studies were included if the design was randomized and included a control group. Drug safety was assessed using data from any patient series or controlled study. DATA SYNTHESIS: Tamsulosin, a uroselective alpha1A-adrenergic receptor antagonist, relaxes smooth muscle in the prostate and bladder neck, thereby enhancing bladder emptying. In randomized, controlled clinical trials using standardized instruments, tamsulosin improves obstructive voiding symptoms by at least 25% in 65-80% of patients with symptomatic benign prostatic hyperplasia. Tamsulosin also improves peak urinary flow rate by 1.4-3.6 mL/sec in various studies and reduces post-void residual urine volume. The usual dosage of tamsulosin was 0.4 or 0.8 mg orally once a day in the studies performed in the US and Europe; daily doses of 0.1-0.4 mg were used in studies performed in Japan. The beneficial effects of tamsulosin on voiding symptoms, peak urinary flow rate, and bladder emptying appear to be dose-related, up to a ceiling dose of 0.4 mg. The most common adverse effects are headache, asthenia, dizziness, and rhinitis-like complaints. Retrograde or delayed ejaculation occurs in 4.5-14.0% of patients and has required discontinuation of treatment in a minority of these patients. At the usual dose of 0.4-0.8 mg/d, tamsulosin does not appear to significantly reduce blood pressure, increase heart rate, or cause first-dose syncope; therefore, dosage titration is not necessary when initiating treatment. Use of nifedipine, enalapril, atenolol, furosemide, or digoxin does not require dosage modification when tamsulosin is initiated concomitantly; hypotension has not been reported with combined use of tamsulosin and these commonly used agents. CONCLUSIONS: Tamsulosin is an improvement over other alpha-adrenergic antagonists for the management of symptoms of benign prostatic hyperplasia. It is a more convenient alternative that does not require initial dosage titration, has a fast onset of action, and has a low potential to cause hypotension when used alone or in combination with commonly used antihypertensive agents. It is more costly than some of the other second-generation alpha-adrenergic antagonists.

Adrenergic alpha-Antagonists↗

PubMed2000

Pediatricians' attitudes, beliefs, and practices regarding clinical practice guidelines: a national survey.

BACKGROUND: Clinical practice guidelines are increasingly being used for a wide variety of medical conditions, but not enough is known about physicians' attitudes and beliefs about guidelines, how often and under what circumstances they are used, and factors associated with their acceptance. OBJECTIVE: To determine practice guideline attitudes, beliefs, practices, and factors associated with use among a representative national sample of general pediatricians. STUDY DESIGN: Cross-sectional mail survey. SUBJECTS: Random sample of general pediatrician members of the American Academy of Pediatrics residing in all 50 states and Puerto Rico. SURVEY INSTRUMENT: Twenty-four multiple-choice, Likert scale, yes-no, and open-ended questions about pediatric clinical practice guidelines. RESULTS: From 1088 respondents, 461 specialists were excluded; the remaining 627 general pediatricians were mostly male (61%), white (81%), and in group practice (62%) in a suburban location (48%). Practice guidelines are used by 35% of pediatricians, in part by 44%, and not at all by 21%. Over 100 different practice guidelines are used, most commonly for asthma (77%), hyperbilirubinemia (27%), and otitis media (19%). Common reasons for use of practice guidelines include standardization of care (17%) and helpfulness (10%). Commonly cited problems with practice guidelines include failure to allow for clinical judgment (54%), use in litigation (16%), and limitation of autonomy (5%). In multivariate analysis, the odds of practice guideline use were greater among pediatricians in health maintenance organization practices (odds ratio [OR]: 9.1; 95% confidence interval [CI]: 1.2-68.0) and those who were nonwhite (OR: 2.3; 95% CI: 1.1-4.8), but lower in those with more weekly patient visits (OR:.7; 95% CI:.5-.9). Features most likely to lead to practice guideline use include simplicity (16%), feasibility (12%), and evidence of improved outcomes (10%). Most pediatricians agree that practice guidelines improve outcomes (89%), are motivated by a desire to improve quality (94%), and should not be used in litigation (82%) or disciplinary actions (77%), nor be motivated by a desire to reduce costs (73%). CONCLUSIONS: Most general pediatricians use practice guidelines, but no specific guidelines, except those for asthma, are used by >27% of pediatricians. The results of this study suggest that practice guidelines are most likely to be followed if they are simple, flexible, rigorously tested, not used punitively, and are motivated by desires to improve quality, not reduce costs.

Attitude of Health Personnel↗

PubMed2000

Primitive neuroectodermal tumors of the brainstem: investigation of seven cases.

OBJECTIVE: We discuss the clinical aspects, pathology, and molecular genetics of 7 patients with primitive neuroectodermal tumors (PNETs) arising in the brainstem that were treated at our institution from 1986 through 1995. Most neuro-oncologists avoid performing biopsies in children with pontine tumors. This article raises the question as to whether biopsies should be performed, because treatment recommendations might differ if a PNET was diagnosed rather than a pontine glioma. PATIENTS AND METHODS: We reviewed the clinical neuro-oncology database and the files of the Division of Neuropathology at New York University Medical Center from 1986 through 1995 and identified 7 histologically confirmed PNETs arising in the brainstem among 146 pediatric brainstem tumors. The clinical, neuroradiological, and neuropathological data were reviewed. Postmortem examinations were performed in 2 cases. Formalin-fixed, paraffin-embedded tumor tissues were also available in 6 of 7 patients that were tested for p53 gene mutations using single-strand conformation polymorphism analysis. We also tested 9 cerebellar PNETs, 9 brainstem gliomas, and 3 normal brains for p53 gene mutations as controls. RESULTS: All 7 patients presented with focal cranial nerve deficits, and 2 were also hemiparetic. The median age at diagnosis was 2.7 (1-8 years). Magnetic resonance imaging (MRI) characteristics included a focal intrinsic exophytic nonenhancing brainstem lesion that had low T1-weighted and high T2-weighted signals. Hydrocephalus was present in 5 patients at diagnosis, 3 of whom had leptomeningeal dissemination. Meningeal dissemination occurred later in the course of the disease in 3 other patients. Five children required shunts at diagnosis and another 2 at recurrence. Despite therapy, all 7 PNET patients died within 17 months of diagnosis with a mean survival of 8 (4-17) months. No mutation in the p53 gene was detected. CONCLUSIONS: Brainstem PNETs tend to arise at a younger age than brainstem gliomas and medulloblastomas. The MRI pattern suggests a localized rather than a diffuse intrinsic nonenhancing brainstem tumor. Like other PNETs, brainstem PNETs have a high predilection to disseminate within the central nervous system. The absence of p53 mutations is similar to other PNETs. Despite their origin close to the cerebellum, brainstem PNETs exhibit a more aggressive behavior and result in worse clinical outcomes than do cerebellar PNETs.

Brain Neoplasms↗

PubMed2000

MR angiography of moyamoya disease before and after encephaloduroarteriosynangiosis.

OBJECTIVE: Our purpose was to evaluate the usefulness of MR angiography in revealing moyamoya disease before and after encephaloduroarteriosynangiosis. SUBJECTS AND METHODS: Twenty-six patients (51 hemispheres) with angiographically confirmed moyamoya disease who underwent encephaloduroarteriosynangiosis were included in the study. Findings on preoperative MR angiography were compared with those on conventional angiography. Postoperative neurologic status was categorized as poor, fair, good, or excellent. Postoperative MR angiography was examined for the appearance of the superficial temporal artery, changes in moyamoya vessels, and transdural collateral vessels into the middle cerebral artery territory. RESULTS: Preoperative MR angiography revealed moyamoya disease in all patients (diagnostic accuracy, 100%). MR angiography correctly depicted the degree of internal carotid artery stenosis in 37 arteries (73%), moyamoya vessels in 33 hemispheres (65%), and the degree of stenosis in the middle, anterior, and posterior cerebral arteries in 125 (82%) of 153 arteries. After surgery, 39 hemispheres showed an excellent outcome, eight showed a good outcome, two a fair outcome, and two a poor outcome. On postoperative MR angiography, vascular supply to the middle cerebral artery territory via transdural collateral vessels increased in 28 hemispheres (55%) and decreased in four (8%). The size of the superficial temporal artery increased in 41 (80%) of 51 hemispheres. The extent of moyamoya vessels decreased in 27 hemispheres (53%) after surgery. CONCLUSION: MR angiography can show the changes in the superficial temporal artery and development of transdural collateral vessels after encephaloduroarteriosynangiosis. Because MR angiography is noninvasive, it is valuable for evaluating postoperative changes.

Adolescent↗