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Biomedical subjects

C Lee

Publications and source records attributed to C Lee.

At least 163 records · Page 9Linked to original sources
PubMed2001

Blockage of complement regulators in the conjunctiva and within the eye leads to massive inflammation and iritis.

The open environment of the eye is continuously subject to an influx of foreign agents that can activate complement. Decay-accelerating factor (DAF), membrane cofactor protein (MCP) and CD59 are regulators that protect self-cells from autologous complement activation on their surfaces. They are expressed in the eye at unusually high levels but their physiological importance in this site is unstudied. In the rat, a structural analogue termed 5I2 antigen (5I2 Ag) has actions overlapping DAF and MCP. In this investigation, we injected F(ab')2 fragments of 5I2 mAb into the conjunctiva and aqueous humor, in the latter case with and without concomitant blockage of CD59. Massive neutrophilic infiltration of the stroma and iris resulted upon blocking 5I2 Ag activity. Frank necrosis of the iris occurred upon concomitant intraocular blockage of CD59. C3b was identified immunohistochemically, and minimal effects were seen in complement-depleted animals and in those treated with non-relevant antibody. The finding that blockage of 5I2 Ag function in periocular tissues and within the eye causes intense conjunctival inflammation and iritis demonstrates the importance of intrinsic complement regulators in protecting ocular tissues from spontaneous or bystander attack by autologous complement.

Animals↗
PubMed2001

Mental health literacy survey of psychiatrically and generally trained nurses employed in a Singapore psychiatric hospital.

Mental health literacy studies consider the capacity of respondents to recognize certain psychiatric disorders, judge the comparative utility of a range of interventions, and make estimates about outcome and prognostic issues. We report such a study involving a sample of nursing staff employed at a large psychiatric institution in Singapore, and who were provided with separate brief vignettes of mania, schizophrenia and depression. Subjects were highly accurate in 'diagnosing' schizophrenia, less accurate for depression and even less accurate in diagnosing mania. Depression was alternately diagnosed as stress, mania was most commonly misdiagnosed as schizophrenia, and for both psychotic conditions, a percentage returned non-psychotic diagnoses. In terms of treatment options, staff distinctly favoured a 'medical model' and viewed traditional and alternative healing options as distinctly harmful. Analyses contrasted psychiatrically trained and generally trained nurses, but identified few significant differences. Such information has the potential to shape the education and training of mental health professional staff, as well as provide important insights about how nurses may diagnose, view and favour alternative treatments and strategies to assist those with common psychiatric disorders.

Data Collection↗
PubMed2001

Effects of oral estrogen and progestin on the lower urinary tract among female nursing home residents.

OBJECTIVE: To examine the effects of oral estrogen/progestin on incontinence and related lower urinary tract conditions among female nursing home (NH) residents. DESIGN: Randomized placebo-controlled trial. SETTING: Five NHs. PARTICIPANTS: Thirty-two incontinent female residents of average age 88. MEASUREMENTS: Subjects were randomized to receive either oral estrogen (0.625 mg) combined with progesterone (2.5 mg) or placebo, daily for 6 months. Measures of incontinence severity, the clinical appearance of the vagina, vaginal and urethral cytology, and urine and vaginal cultures were made at baseline, 3 months, and 6 months. In addition to active drug or placebo, all subjects received regular toileting assistance (prompted voiding) by trained research aides during 3-day data-collection periods to compensate for mobility and cognitive impairments. RESULTS: At 3 and 6 months there were no significant differences between the groups in the severity of incontinence, the prevalence of bacteriuria, or the results of vaginal cultures. Several clinical findings associated with atrophic vaginitis improved more in the active than the placebo group and vaginal pH and vaginal and urethral cytology exhibited a partial estrogenic effect. CONCLUSIONS: Our results must be interpreted with caution because of the size and the select nature of our subject sample. Up to 6 months of oral estrogen had only a partial estrogenic effect on vaginal and urethral epithelium and no clinical effects in this patient population. We believe that future studies of estrogen for urinary incontinence in frail NH residents should utilize a topical preparation and consider targeting urinary tract infection as an additional outcome measure.

Activities of Daily Living↗
PubMed2001

Two separate unintentional fatalities with the same revolver.

We report 2 deaths and 1 injury that resulted from 2 separate unintentional discharges of the same Ruger Blackhawk revolver. One discharge was a consequence of careless firearm handling combined with a slip during a decocking procedure unique to certain hammer-action firearms. The second discharge occurred when the firearm was dropped and was the result of a combination of firearm design and a lack of knowledge regarding the safe handling of this type of revolver. The second death may have been prevented by the timely intervention of a health care or law enforcement professional at the time of the first unintentional discharge. Physicians who become knowledgeable about the functioning of different types of firearms and how they can malfunction may help promote the safe and responsible use of firearms among their patients.

Abdominal Injuries↗
PubMed2001

Natural occurrence of aflatoxins in Korean meju.

Aflatoxin B1 (AFB1) was found in 35 of 60 (58.3%) meju samples with an average concentration of 7.3 ng/g by ELISA. Contamination of AFB1 was confirmed in 25 of 60 samples (41.6%) using HPLC, with an average concentration of 6.9 ng/g. Mean recoveries from meju ranged from 107% to 170% for AFB1 using ELISA at a spiking range of 1 to 50 ng/g. Over the same range, recoveries using HPLC were from 70% to 83%. The levels of AFB1 determined by ELISA and by HPLC demonstrated a close relationship between the two methods (r2 = 0.9324) employed in this study. In order to evaluate the potential health risks of AFB1 on Koreans consuming meju, we calculated the estimated probable daily intake (PDI) based on the average contamination levels and compared it with the estimated tolerable daily intake (TDI). The PDIs of AFB1 from kanjang and dwenjang were determined to be 0.04 and 0.21 ng/kg bw/day, respectively, and were higher than TDIs.

Aflatoxin B1↗
PubMed2001

The analgesic interaction between intrathecal clonidine and glutamate receptor antagonists on thermal and formalin-induced pain in rats.

UNLABELLED: Clonidine, an alpha(2) adrenergic receptor agonist, inhibits glutamate release from the spinal cord. We studied the interaction of intrathecally administered clonidine and glutamate receptor antagonists on acute thermal or formalin induced nociception. Sprague-Dawley rats with lumbar intrathecal catheters were tested for their tail withdrawal response by the tail flick test and paw flinches produced by formalin injection after intrathecal administration of saline, clonidine, AP-5 (a N-methyl-D-aspartate receptor antagonist), or YM872 (an alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor antagonist). The combinations of clonidine and the other two agents were also tested by isobolographic analyses. Motor disturbance and behavioral changes were observed as side effects. The ED(50) values of clonidine decreased from 0.26 microg (tail flick), 0.12 microg (Phase 1) and 0.13 microg (Phase 2) to 0.036 microg, 0.006 microg, and 0.013 microg with AP-5, and 0.039 microg, 0.057 microg, and 0.133 microg with YM872, respectively. Side effects were attenuated in both combinations. In conclusion, spinally administered clonidine and AP-5 or YM872 exhibited potent synergistic analgesia on acute thermal and formalin-induced nociception with decreased side effects in rats. IMPLICATIONS: Combinations of a spinally administered alpha(2) adrenergic receptor agonist and an a N-methyl-D-aspartate receptor antagonist or an alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor antagonist exhibited potent synergistic analgesia in acute thermal and inflammatory-induced nociception with decreased side effects.

Adrenergic alpha-Agonists↗
PubMed2001

Neoadjuvant chemoradiation for rectal cancer: analysis of clinical outcomes from a 13-year institutional experience.

OBJECTIVE: To examine clinical outcomes in patients receiving neoadjuvant chemoradiation for locally advanced rectal adenocarcinoma. SUMMARY BACKGROUND DATA: Preoperative radiation therapy, either alone or in combination with 5-fluorouracil-based chemotherapy, has proven both safe and effective in the treatment of rectal cancer. However, data are lacking regarding which subgroups of patients benefit from the therapy in terms of decreased local recurrence and increased survival rates. METHODS: A retrospective chart review was performed on 141 consecutive patients who received neoadjuvant chemoradiation (5-fluorouracil +/- cisplatin and 4,500-5,040 cGy) for biopsy-proven locally advanced adenocarcinoma of the rectum. Surgery was performed 4 to 8 weeks after completion of chemoradiation. Standard statistical methods were used to analyze recurrence and survival. RESULTS: Median follow-up was 27 months, and mean age was 59 years (range 28-81). Mean tumor distance from the anal verge was 6 cm (range 1-15). Of those staged before surgery with endorectal ultrasound or magnetic resonance imaging, 57% of stage II patients and 82% of stage III patients were downstaged. The chemotherapeutic regimens were well tolerated, and resections were performed on 140 patients. The percentage of sphincter-sparing procedures increased from 20% before 1996 to 76% after 1996. On pathologic analysis, 24% of specimens were T0. However, postoperative pathologic T stage had no effect on either recurrence or survival. Positive lymph node status predicted increased local recurrence and decreased survival. CONCLUSIONS: Neoadjuvant chemoradiation is safe, effective, and well tolerated. Postoperative lymph node status is the only independent predictor of recurrence and survival.

Adenocarcinoma↗
PubMed2001

Radiological control for 203Hg radiotracer determinations of mercury inventories at chlor-alkali plants.

20Hg has been used safely to determine mercury inventories in large electrochemical process cells in the chlorine industry by a process of isotopic dilution. Laboratory conversion and processing of irradiated HgO can be done in closed systems with non-detectable releases to work areas or the environment and with exposure to whole body <0.25 mSv (25 mrem) and <3 mSv (300 mrem) to extremities. Personnel exposures during plant operations are controlled to non-detectable levels for whole body exposure and <0.3 mSv (30 mrem) to extremities for the operator; exposures for other plant personnel are non-detectable.

Air Pollution, Radioactive↗
PubMed2001

Multicolor fluorescence in situ hybridization in clinical cytogenetic diagnostics.

Multicolor fluorescence in situ hybridization is a technology that has vastly expanded the diagnostic repertoire of the clinical cytogenetics laboratory. The limitations of conventional chromosome banding analysis can often be overcome by the high sensitivity and specificity of multicolor fluorescence in situ hybridization tests. This article reviews the latest multicolor fluorescence in situ hybridization tests (including multiplex fluorescence in situ hybridization, spectral karyotyping, cross-species color banding, and comparative genomic hybridization) that are currently limited to a few select clinical cytogenetic laboratories, but may soon have more dominant roles in clinical cytogenetic practice.

Animals↗
PubMed2001

Cavities of alpha(1)-antitrypsin that play structural and functional roles.

The native form of inhibitory serine protease inhibitors (serpins) is strained, which is critical for their inhibitory activity. Previous studies on stabilizing mutations of alpha(1)-antitrypsin, a prototype of serpins, indicated that cavities provide a structural basis for the native strain of the molecule. We have systematically mapped the cavities of alpha(1)-antitrypsin that play such structural and functional roles by designing cavity-filling mutations at residues that line the walls of the cavities. Results show that energetically unfavorable cavities are distributed throughout the alpha(1)-antitrypsin molecule, and the cavity-filling mutations stabilized the native conformation at 8 out of 10 target sites. The stabilization effect of the individual cavity-filling mutations of alpha(1)-antitrypsin varied (0.2-1.9 kcal/mol for each additional methylene group) and appeared to depend largely on the structural flexibility of the cavity environment. Cavity-filling mutations that decreased inhibitory activity of alpha(1)-antitrypsin were localized in the loop regions that interact with beta-sheet A distal from the reactive center loop. The results are consistent with the notion that beta-sheet A and the structure around it mobilize when alpha(1)-antitrypsin forms a complex with a target protease.

Amino Acid Substitution↗
PubMed2001

Pediatric emergency assessment tool (PEAT): a risk-adjustment measure for pediatric emergency patients.

OBJECTIVE: To develop a multivariable model predicting the level of care required by pediatric patients for use as a risk-adjustment tool in the evaluation of emergency medical services for children. METHODS: A random 10% sample of records of all visits over a 12-month period to a suburban, university-affiliated pediatric emergency department (PED) was selected and abstracted. The outcome variable, level of care received, was categorized in three levels: routine care only (R); diagnostic or therapeutic procedures performed in the ED but patient not admitted (EDT); and admission to hospital (ADM). Predictor variables included information routinely elicited and recorded at the time of triage. Using multinomial logistic regression, a predictive model was derived from a subset of 70% of the selected visits, and was validated in the remaining 30%. RESULTS: The total sample included 2,287 visits. The overall rate of each outcome was R-37%, EDT-53%, and ADM-10%. The final regression model included the following predictors significantly associated with the outcome: age, past medical history, temperature, abnormal respiratory rate or pulse oximetry in triage, chief complaint, and triage level (model likelihood ratio chi-square, 14 df = 332, p < 0.00001, R(2) = 0.14). The number of outcomes was well predicted by the model in both subsamples. Analysis of variance showed a significant association between Pediatric Emergency Assessment Tool (PEAT) score (weighted sum of the predicted probabilities of EDT and ADM) and both ED charges and time spent in the ED (p < 0.001). CONCLUSIONS: A model based on easily and routinely measured variables can accurately predict the level of care rendered in the PED. The predicted probabilities from such a model correlate well with other outcomes of care and may be useful in adjusting for differences in risk when evaluating quality of care.

Child, Preschool↗
PubMed2001

Characterisation of lymphosarcomas in Australian cats using polymerase chain reaction and immunohistochemical examination.

OBJECTIVE: To examine tumour tissue of cats with lymphosarcoma for the presence of feline leukaemia virus and feline immunodeficiency virus and analyse the immunophenotype of the tumours. DESIGN: A retrospective study of feline lymphosarcoma cases. METHODS: Formalin-fixed, paraffin-embedded tumour tissue of 14 feline lymphosarcomas was examined for the presence of feline leukaemia virus and feline immunodeficiency virus by polymerase chain reaction and immunohistochemistry. Using polyclonal and monoclonal antibodies against T and B lymphocytes, the phenotypic expression of the tumours was characterised. RESULTS: No feline leukaemia virus antigen or proviral sequences were detected. Feline immunodeficiency virus proviral sequences were detected in two cases by polymerase chain reaction. Immunophenotyping of all 14 cases resulted in seven cases being classified as B-cell phenotype, four as T-cell phenotype, and the remaining three undetermined. CONCLUSIONS: In contrast to previous reports overseas, our results suggest that feline leukaemia virus infection appears to be an infrequent cause of lymphosarcoma in the cats that were necropsied. Feline immunodeficiency virus may have a role in lymphomagenesis. The potential role of feline immunodeficiency virus needs to be explored in more depth. Compared with most previous reports, B-cell tumours were more common than T-cell tumours in this series of cats.

Animals↗
PubMed2001

A noninvasive estimation of hypernasality using a linear predictive model.

The pronunciation of a speaker with a defective soft palate is marked by hypernasality and an operation may be necessary to repair the defective soft palate to reduce this hypernasality. An assessment of hypernasality is necessary to quantify the effect of the surgery. The current clinical methods for assessing hypernasality are uncomfortable or require expensive equipment. In this paper, a new quantitative method is proposed to estimate hypernasality. This method requires only a microphone and a personal computer equipped with a sound card. Zeros in the frequency response of the vocal tract system are one of the major characteristics of hypernasality. The proposed method made use of the fact that a linear predictive model with a typical order for the human vocal tract system is not accurate when the vocal tract system has zeros in its frequency response. Hypernasality was estimated by comparing the distance between the sequences of linear predictive cepstrum of low- and high-order linear predictive models. The proposed method provides a better correlation (0.58) with nasalance measured by a nasometer than Teager method (0.44) for all the data. Furthermore, the proposed method showed higher correlation of 0.84 than 0.71 of the Teager method for data with a nasalance higher than 35%. Since the proposed method needs only digitized speech data, it is much less invasive and provides an easy and cost-effective evaluation of hypernasality.

Biomedical Engineering↗
PubMed2001

Regulation of Staphylococcus aureus type 5 and type 8 capsular polysaccharides by CO(2).

Staphylococcus aureus expression of capsular polysaccharide type 5 (CP5) has been shown to be downregulated by CO(2). Here we show that CO(2) reduces CP5 expression at the transcriptional level and that CO(2) regulates CP8 expression depending on the genetic background of the strains. Growth in the presence of air supplemented with 5% CO(2) caused a significant decrease in CP8 expression in four S. aureus strains, a marginal effect in four strains, and higher CP8 expression in strain Becker. Absolute CP8 expression in the nine S. aureus strains differed largely from strain to strain. Four groups of strains were established due to sequence variations in the promoter region of cap5 and cap8. To test whether these sequence variations are responsible for the different responses to CO(2), promoter regions from selected strains were fused to the reporter gene xylE in pLC4, and the plasmids were electrotransformed into strains Becker and Newman. XylE activity was negatively regulated by CO(2) in all derivatives of strain Newman and was always positively regulated by CO(2) in all derivatives of strain Becker. Differences in promoter sequences did not influence the pattern of CP8 expression. Therefore, the genetic background of the strains rather than differences in the promoter sequence determines the CO(2) response. trans-acting regulatory molecules may be differentially expressed in strain Becker versus strain Newman. The strain dependency of the CP8 expression established in vitro was also seen in lung tissue sections of patients with cystic fibrosis infected with CP8-positive S. aureus strains.

Bacterial Capsules↗