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Biomedical subjects

H Lee

Publications and source records attributed to H Lee.

At least 55 records · Page 3Linked to original sources
PubMed2005

Stability of lyophilized and reconstituted plasma/albumin-free recombinant human factor VIII (ADVATE rAHF-PFM).

Traditionally the serum protein albumin has been used to stabilize lyophilized recombinant factor VIII (rFVIII) products. Advanced rFVIII products have now been developed that employ other stabilizers. ADVATE antihaemophilic factor (recombinant), plasma/albumin-free method (rAHF-PFM) utilizes trehalose and mannitol as stabilizers in the lyophilized preparation. An extensive in vitro evaluation was conducted on the stability of rAHF-PFM as measured by retained activity over time. Both lyophilized and reconstituted rAHF-PFM were analysed, and the full range of available potencies were tested under varying temperature conditions. Lyophilized rAHF-PFM exhibited a high degree of stability under a range of conditions. The mean retained activity of 15 rAHF-PFM lots (ranging from low to maximal potency) at 5 degrees C for 30 months was 91.6% (95% CI, 88.9-94.3%) of initial potency. rAHF-PFM also remained highly stable after storage at room temperature for 18 months, with 82.0% (95% CI, 79.2-84.9%) of initial activity retained at 25 degrees C and 79.1% (95% CI, 76.2-81.9%) at 30 degrees C. All other parameters, including moisture, appearance, solubility, pH and aggregation remained within the established product specifications. The mean retained activity after 1 month of storage at 40 degrees C was 94.0% (95% CI, 92.4-95.6%). A high temperature excursion to 40 degrees C for 2 weeks did not compromise subsequent stability of the lyophilized powder either under refrigeration or at room temperature. Reconstituted samples from 11 rAHF-PFM lots retained an average of 92.0% (95% CI, 89.8-94.3%) activity after 24 h. The present study provides evidence of good stability at differing temperatures of an albumin-free formulated rFVIII product.

Chemistry, Pharmaceutical↗
PubMed2005

Application of remote monitoring and automatic control system using neural network for small wastewater treatment plants in Korea.

For this study, an automatic control system has been developed by using a neural network and internet-based remote monitoring system for efficient operation of plants that have a serious variance of influent loading and have difficulties in appropriate maintenance, just like small wastewater treatment plants in Korea. In the control algorithm, ORP was used as the main sensor for control. At the point where the ORP value was judged to reach the "nitrate knee" of denitrification and phosphorus release, ORP indicated the state of lower saturation read by the neural network and then changed the operating condition from the reduction state to the oxidation state. For example, if ORP indicates the state of higher saturation at the point of "nitrogen breakpoint" or "ammonia valley" of nitrification, the neural network reads it and cuts off the oxygen supply and mixing. The dORP data have been used as one of the main input for the neural network. After the operation of lab-scale cyclic aeration process using an automatic control system, it has been found that regardless of loading variance, more than 95% of organic matters and more than 60% of nitrogen and phosphorus have been removed. Assuming that an internet-connected computer and a basic web browser are available, this study has developed a remote monitoring system that can monitor the operating status of small plants or any troubles with them.

Automation↗
PubMed2004

Suggestive linkage to chromosome 6q in families with bilateral vestibulopathy.

BACKGROUND: Of the more than 40 genetically defined dominantly inherited hearing loss syndromes, only a few are associated with bilateral vestibulopathy. No genetic mutations have been identified in families with bilateral vestibulopathy and normal hearing. OBJECTIVE: To perform a genome-wide scan for linkage in four families with dominantly inherited bilateral vestibulopathy. METHODS: Patients in four families reported brief episodes of vertigo followed by imbalance and oscillopsia. Bilateral vestibulopathy was documented with quantitative rotational testing. Most patients with bilateral vestibulopathy also had migraine. A 10 cM genome-wide screen was conducted using 423 microsatellite markers to identify linkage with vestibulopathy. RESULTS: The authors identified a 24 cM region on chromosome 6q suggestive of linkage to vestibulopathy in these four families (maximum lod score of 2.9 at marker D6S1556). A small fifth family with a different phenotype was not linked to this region on chromosome 6q. CONCLUSIONS: This is the first report of linkage in families with dominantly inherited vestibulopathy and normal hearing. Genetic heterogeneity is likely with inherited vestibulopathy.

Chromosomes, Human, Pair 6↗
PubMed2004

HO-1 induction restores c-AMP-dependent lung epithelial fluid transport following severe hemorrhage in rats.

Inhibition of cAMP-dependent stimulation of the vectorial fluid transport across the lung epithelium following hemorrhagic shock is mediated by NO released within the airspaces of the lung. We tested here the hypothesis that prior induction of HO-1 would attenuate the release of NO in the airspaces, thus preventing the inhibition of the c-AMP stimulation of alveolar fluid clearance (ALC) in rats. Indeed, HO-1 induction restored the cAMP-mediated up-regulation of ALC after hemorrhage by decreasing NO released within the airspaces of the lung. In vitro studies demonstrated that HO-1 induction significantly reduced the iNOS-mediated release of NO by alveolar macrophages stimulated with endotoxin for 24 h. This effect is explained in part by a HO-1-dependent attenuation of the LPS-mediated nuclear translocation of NF-kappaB. In addition, HO-1 induction also significantly reduced the iNOS-mediated release of NO by MH-S cells that were stimulated with interferon-gamma by decreasing the phosphorylation of STAT 1, another transcription factor important for the activation of the iNOS promoter. In contrast, HO-1 induction did not affect the production of NO by rat alveolar epithelial type II cells that were stimulated with cytomix (a mixture of TNF-alpha, IL-1beta, and IFN-gamma) for 24 h. In summary, these results provide the first in vivo evidence that the induction of HO-1 in the lung restores a normal fluid transport capacity of the alveolar epithelium following hemorrhagic shock by inhibiting the iNOS-mediated release of NO by alveolar macrophages.

Animals↗
PubMed2004

The role of central mu opioid receptors in opioid-induced itch in primates.

Pruritus (itch sensation) is a significant clinical problem. The aim of this study was to elucidate the roles of opioid receptor types and the site of action in opioid-induced itch in monkeys. Observers who were blinded to the conditions counted scratching after administration of various drugs. Intravenous (i.v.) administration of mu opioid receptor (MOR) agonists (fentanyl, alfentanil, remifentanil, and morphine) evoked scratching in a dose- and time-dependent manner. However, the kappa opioid agonist U-50488H [trans-(+/-)-3,4-dichloro-N-methyl-N-(2-[1-pyrrolidinyl]-cyclohexyl)-benzeneacetamide] and delta opioid agonist SNC80 [(+)-4-[(alphaR)-alpha-[2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl]-3-methoxybenzyl]-N,N-diethylbenzamide] did not increase scratching. Intrathecal (i.t.) administration of peptidic MOR agonist [D-Ala2,N-Me-Phe4,Gly5-ol]-enkephalin (DAMGO, 0.00032-0.01 mg) evoked scratching, but i.v. DAMGO (0.01-1 mg/kg) did not increase scratching. A similar difference between i.t. and i.v. effectiveness was seen with morphine. Antagonist studies revealed that i.v. administration of an opioid receptor antagonist (naltrexone, 0.0032-0.1 mg/kg) dose dependently attenuated scratching induced by i.v. fentanyl (0.018 mg/kg) or morphine (1 mg/kg). However, a peripherally selective opioid antagonist (quaternary naltrexone, 0.0032-0.32 mg/kg) did not block i.v. fentanyl- or morphine-induced scratching. Moreover, a histamine antagonist (diphenhydramine, 0.1-10 mg/kg), failed to attenuate scratching induced by i.t. morphine (0.032 mg) or i.v. morphine (1 mg/kg). Pretreatment with a selective MOR antagonist (clocinnamox, 0.1 mg/kg), but not kappa or delta opioid antagonists (nor-binaltorphimine or naltrindole), blocked i.t. morphine-induced scratching. Together, these data suggest that MOR, not other opioid receptor types or histamine, mediates scratching evoked by opioid analgesics. More important, this study provides in vivo pharmacological evidence that activation of central MOR plays an important role in opioid-induced itch in primates.

Analgesics, Opioid↗
PubMed2004

Respite care for people with dementia and their carers.

BACKGROUND: Caring for someone with dementia can be emotionally and physically demanding. Respite care is any intervention designed to give rest or relief to caregivers. It is not clear what positive and negative effects the provision of respite care may have on people with dementia and their caregivers. OBJECTIVES: To assess the effects of respite care for people with dementia and their caregivers, in particular the effect of respite care on rates of institutionalization. SEARCH STRATEGY: The trials were identified from a last updated search of the Cochrane Dementia and Cognitive Improvement Group's Specialized Register on 2 July 2003 using the terms respite* and "day care". This Register contains up to date records from all major health care databases and many ongoing trial databases. SELECTION CRITERIA: Randomized controlled trials comparing respite care with a control intervention for people with dementia. DATA COLLECTION AND ANALYSIS: Both reviewers carried out study selection independently and reached a consensus through discussion. Data was extracted by a single reviewer. The reviewers contacted all investigators for methodological details not reported in the text and for additional data. MAIN RESULTS: Three trials were included in the review. They were different in many ways including intervention, duration and outcomes so pooling of data was not possible. Re-analysis of outcomes using data from the published studies found no significant effects of respite care on any variable. REVIEWERS' CONCLUSIONS: Current evidence does not demonstrate any benefits or adverse effects from the use of respite care for people with dementia or their caregivers. These results should be treated with caution, however, as they may reflect the lack of high quality research in this area rather than an actual lack of benefit. Given the frequency with which respite care is advocated and provided, well-designed trials in this area are needed.

Aged↗
PubMed2004

Oxidative stress is the master operator of drug and chemically-induced programmed and unprogrammed cell death: Implications of natural antioxidants in vivo.

ROS, RNS, BRIs and ROS-RNS hybrids are produced during drug or chemical metabolism in vivo. These reactive species are instrumental to the culmination of cellular oxidative stress (OS). OS, once turned on, does not spare any vital intracellular macromolecule, such as glutathione, DNA, RNA, proteins, enzymes, lipids and ATP. Since concentration gradients of such components are very delicately balanced for normal cellular functioning, a gross perturbation leads to cell injury and cell death. Abundant evidence now suggests that intracellular antioxidants keep OS in check and maintain homeostasis. Our laboratory has focused on the role of OS in orchestrating various forms of cell death during drug and chemically-induced target organ toxicity and their counteraction by various natural or synthetic antioxidants in in vivo models. Despite complexity of the in vivo models, results show that metabolism of xenobiotics are invariably associated with different degrees of OS and natural antioxidants such as grape seed extract, bitter melon extract (Momordica charantia) and N-acetylcysteine (NAC) which were very effective in counteracting organ toxicities by minimizing events linked to OS (lipid peroxidation and total glutathione), and CAD-mediated DNA fragmentation. Phytoextract exposure rescued cells from toxic assaults, protected genomic integrity, and minimized apoptotic, necrotic and apocrotic (oncotic necrosis) cell deaths. Pre-exposure mode was more effective than post-exposure route. Overall scenario suggests that OS may have been the prime modulator of death and/or survival programs, whereas, antioxidants may have imparted a dual role in either erasing death signals or reviving survival signals, and a combination of antioxidants may be more beneficial than a single entity to influence a number of intracellular events operating simultaneously to neutralize chaotic toxicological consequences.

Acetaminophen↗
PubMed2004

Biology, persistence and detection of Cryptosporidium parvum and Cryptosporidium hominis oocyst.

Cryptosporidium parvum and Cryptosporidium hominis are obligate enteric protozoan parasites which infect the gastrointestinal tract of animals and humans. The mechanism(s) by which these parasites cause gastrointestinal distress in their hosts is not well understood. The risk of waterborne transmission of Cryptosporidium is a serious global issue in drinking water safety. Oocysts from these organisms are extremely robust, prevalent in source water supplies and capable of surviving in the environment for extended periods of time. Resistance to conventional water treatment by chlorination, lack of correlation with biological indicator microorganisms and the absence of adequate methods to detect the presence of infectious oocysts necessitates the development of consistent and effective means of parasite removal from the water supply. Additional research into improving water treatment and sewage treatment practices is needed, particularly in testing the efficiency of ozone in oocyst inactivation. Timely and efficient detection of infectious C. parvum and C. hominis oocysts in environmental samples requires the development of rapid and sensitive techniques for the concentration, purification and detection of these parasites. A major factor confounding proper detection remains the inability to adequately and efficiently concentrate oocysts from environmental samples, while limiting the presence of extraneous materials. Molecular-based techniques are the most promising methods for the sensitive and accurate detection of C. parvum and C. hominis. With the availability of numerous target sequences, RT-PCR will likely emerge as an important method to assess oocyst viability. In addition, a multiplex PCR for the simultaneous detection of C. parvum, C. hominis and other waterborne pathogens such as Giardia lamblia would greatly benefit the water industry and protect human health.

Animals↗
PubMed2004

Utility of osteopontin as a biomarker in recurrent epithelial ovarian cancer.

OBJECTIVE: Osteopontin (OPN) is overexpressed in tumors and serum of ovarian cancer patients and may serve as a biomarker. To evaluate the utility of serum osteopontin in monitoring disease status, we evaluated 234 serum samples from post-oophorectomy patients with ovarian cancer and 38 samples from healthy controls. METHODS: Serum samples were collected from 203 women with recurrent ovarian cancer and 31 newly diagnosed women participating in an experimental chemotherapeutic clinical trial. Controls included 11 young healthy women and 27 peri- or postmenopausal women without ovarian cancer. Samples were assayed for osteopontin using an enzyme-linked immunosorbent assay (ELISA) kit. Statistical analyses for group comparisons of biomarker distribution used the nonparametric Wilcoxon's rank sum test for two-group comparisons and the Kruskal-Wallis test for three-group comparisons. RESULTS: Osteopontin values ranged from 25 to 1463 ng/ml for patients and 25 to 617 ng/ml for controls. Mean patient levels were lower than mean control levels (74 ng/ml vs. 147 ng/ml, respectively, P = 0.0006). Serum osteopontin levels correlated with recurrent disease versus remission (68 ng/ml vs. 34 ng/ml, P = 0.0034), presence of ascites versus absence (71 ng/ml vs. 53 ng/ml, P = 0.0002), and bulky disease vs. nonbulky disease (75 ng/ml vs. 38 ng/ml, P = 0.0005). CA-125 values yielded the same trends with greater statistical difference. CONCLUSIONS: These results demonstrate that serum osteopontin concentrations in post-oophorectomy patients with recurrent ovarian cancer are not greater than in healthy controls. Nevertheless, within this heterogeneous patient population, the values do correlate with bulk of disease. The potential utility of this assay in monitoring women with CA-125 negative disease is worthy of exploration.

Biomarkers, Tumor↗
PubMed2004

Attitudes to chemotherapy in patients with ovarian cancer.

BACKGROUND: Recurrent ovarian cancer (OVCA) has become the model for cancer as a chronic disease, yet little is known about what motivates patients and physicians in treatment choices. METHODS: We investigated the attitudes of patients with epithelial OVCA and staff towards palliative chemotherapy for recurrent OVCA with a cross-sectional questionnaire study. RESULTS: Instruments were developed and piloted in 15 patients. This exploratory study reflects substantial bias in the sample populations. One hundred twenty-two patients and 37 staff were enrolled in the US and 39 patients and 25 staff were enrolled in the UK. UK patients had a lower educational status (P = 0.001), lower stage disease (P = 0.025), and less prior lines of chemotherapy (P < 0.001). 61% of patients had recurrent OVCA and 67% of staff were physicians. Seventy-three percent of patients recalled a discussion about prognosis and 74% wanted to know details of the prognosis for a typical patient (US = UK). Most patients (48%) thought that their physician was realistic, and 57% of staff felt that they were optimistic. The vast majority of both staff and patients thought that patients positively reinterpreted what they were told. Five percent of staff thought that palliative care was "incompatible" when considering chemotherapy as an option for their second recurrence of OVCA, compared with 36% of US patients, significantly more than the 12% of UK patients (P = 0.007). Patients thought that standard chemotherapy for a second recurrence of OVCA produced remission in 50% and cure in 15% of patients. Staff reported 20% and 0%, respectively. Fifty percent of patients and 57% of staff would want chemotherapy as an asymptomatic patient with a normal CT and a rising CA-125. Patients generally appear to be very tolerant of grade II chemotherapy-induced toxicity with staff being less tolerant than patients of nausea, anorexia, diarrhea, and rash. Staff rated life prolongation by 3 months to 1 year very much less acceptable than patients (P < 0.001). Although possibly allowing comprehensive collection of sensitive data, the questionnaire was too distressing for some patients and made 11% of patients feel uncomfortably anxious. CONCLUSIONS: Patients are optimistic and in the US, may be more reluctant than staff to see the Palliative Care Team. These data challenge the assertion that the use of palliative chemotherapy is physician-driven.

Adult↗
PubMed2004

Prevalence and correlates of orthostatic hypotension in middle-aged men and women in Korea: the Korean Health and Genome Study.

To examine the prevalence and correlates of orthostatic hypotension (OH) in middle-aged adults enrolled in the Korean Health and Genome Study. Participants were 8908 individuals aged 40-69 years. Supine blood pressure (BP) was measured three times at 30-s intervals after at least 5 min of rest in the supine position and single standing BP was measured at 0 and 2 min after standing, respectively. OH was defined as a reduction in systolic BP or diastolic BP > or = 20 and 10 mmHg, respectively. The prevalence of OH at 0 and 2 min after standing was 12.3 and 2.9%, respectively. At 0 min of standing, OH frequency increased significantly with age from 6.4% in those aged 40-44 years to 23.1% in those aged 65-69 (P < 0.001). After adjustment for age and other characteristics, hypertension was associated with a 1.7-fold excess in the odds of OH in men and a 1.6-fold excess in women (P < 0.001). In contrast, an increase in body mass index (BMI) on the order of 5 kg/m2 was associated with a 20-30% reduction in the odds of OH (P < 0.001). Diabetes in women was also associated with a 1.4-fold excess in the odds of OH (P < 0.05). An increase in triglyceride by 136 mg/dl in men was associated with an increase in the odds of OH (P < 0.05). In conclusion, the prevalence and correlates of OH other than diabetes and triglycerides were notably similar in men and women. While the association between hypertension and OH has been observed elsewhere, low BMI in Korean adults with OH may be an important marker for subclinical morbidity or coexisting risk factors that need to be identified.

Age Factors↗
PubMed2004

Evaluation of sICAM-1, sVCAM-1, and sE-Selectin levels in patients with metastatic breast cancer receiving high-dose chemotherapy.

Soluble forms of some cell adhesion molecules (CAM), sICAM-1, sVCAM-1, and sE-selectin, are elevated in the sera and plasma of patients with inflammation, arthritis, diabetes, and cancer. Increased levels of these soluble molecules in patients with cancer have been shown to correlate with disease progression and survival. This suggests that increased expression of the soluble forms of CAMs may play an important role in cancer cell growth and metastasis and may be prognostic and/or predictive of malignant disease. In this retrospective study, we assessed the clinical significance of sICAM-1, sVCAM-1, and sE-selectin in 95 patients with metastatic breast cancer enrolled in clinical trials of high-dose chemotherapy (HDC) and autologous stem cell transplantation (ASCT). The significance of soluble HER-2 (sHER-2) and sFAS status, determined in previous studies for this group of patients, was also included in this analysis. Univariate analysis showed that sICAM-1, sVCAM-1, sFas, sHER-2 positive status, and the presence of liver metastases were significant prognostic factors for both progression-free survival (PFS) and overall survival (OS) in the total patient group. In multivariable analysis, HER-2 and sFAS were shown to be independent prognostic factors for PFS and OS. Within the various treatment groups examined, sICAM-1 was a prognostic factor for clinical outcome for patients with metastatic breast cancer enrolled in trials with cyclophosphamide- and carboplatin-based or vinblastine-based HDC, but not in trials with paclitaxeland cyclophosphamide-based HDC.

Adult↗
PubMed2004

Imbalance between matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 in toluene diisocyanate-induced asthma.

BACKGROUND: Toluene diisocyanate (TDI)-induced asthma is an inflammatory disease of the airways characterized by airway remodelling due, at least in part, to an excess of extracellular matrix deposition in the airway wall. The ratio of matrix metalloproteinase-9 (MMP-9) and its inhibitor, tissue inhibitor of metalloproteinase-1 (TIMP-1) may be a marker of the balance between airway tissue destruction and repair. OBJECTIVE: We determined whether an imbalance of the MMP-9 : TIMP-1 molar ratio is present before and/or after challenge with TDI. METHODS: We used a murine model of TDI-induced asthma to evaluate the MMP-9 and TIMP-1 balance in the lung. RESULTS: The expression of MMP-9 and TIMP-1 mRNAs and proteins in the lungs increased at 7 h after TDI inhalation and continued for up to 72 h. Immunohistochemical and immunocytological analyses in the lungs of TDI-exposed mice revealed increases of immunoreactive MMP-9 and TIMP-1. There were significant correlations between the levels of MMP-9 or TIMP-1 and the number of neutrophils, lymphocytes, or eosinophils. The molar ratio of MMP-9/TIMP-1 significantly decreased at 7 h after TDI inhalation and continued up to 72 h. CONCLUSION: These data suggest that TDI-induced asthma may be associated with an imbalance between MMP-9 and TIMP-1, which could be useful as a marker of airway inflammation and airway remodelling in this disease.

Animals↗
PubMed2004

Influence of recipient and donor IL-1alpha, IL-4, and TNFalpha genotypes on the incidence of acute renal allograft rejection.

AIMS: To determine whether polymorphisms of the genes encoding donor or recipient interleukin 1alpha (IL-1alpha), tumour necrosis factor alpha (TNFalpha), or IL-4 have any impact on the incidence of acute rejection after renal transplantation. METHODS: All donors and recipients were genotyped for three polymorphisms in the three cytokine genes: IL1A -889, TNFA -308, and IL4 -590. RESULTS: Statistical analysis of the data obtained revealed no association between the cytokine gene polymorphisms tested and the incidence of post-transplant acute rejection. After stratification for human leucocyte antigen (HLA) matching, it was found that kidneys from donors positive for the TNFA-A allele had a significantly increased incidence of acute rejection in HLA-DR mismatched transplants. CONCLUSIONS: This finding argues for prospective TNFA genotyping of renal donors, with avoidance of allocation of kidneys from donors positive for the TNFA-A allele to HLA-DR mismatched recipients.

Acute Disease↗
PubMed2004

Cavitation phenomenon in monoleaflet mechanical heart valves with electrohydraulic total artificial heart.

Recently, cavitation on the surface of mechanical heart valves has been studied as a cause of fractures occurring in implanted mechanical heart valves. In this study, to investigate the mechanism of cavitation bubbles associated with monoleaflet mitral valves in an electrohydraulic total artificial heart (EHTAH), and to select the best valves for our EHTAH system, we measured three parameters. First, an image was created of the cavitation bubbles using a high-speed camera. Second, pressure drop in the vicinity of the valve surface was measured using mini pressure sensor. Then, the closing of the valve was observed using a Laser displacement sensor. Most of the cavitation bubbles in the Medtronic Hall valve were observed at the edge of the valve stop. With the Omnicarbon valve, the cavitation bubbles were observed at the edge of the valve and on the inner side of the leaflet. On the other hand, cavitation bubbles were observed only on the inner side of the leaflet in Björk-Shiley valve. Cavitation bubbles concentrated on the edge of the valve stop; the major cause of these cavitation bubbles was determined to be the squeeze flow. The formation of cavitation bubbles depended on the valve closing velocity and the valve leaflet geometry. From a viewpoint of squeeze flow, a low closing velocity and a small size of the valve stop could minimize cavitation.

Blood Pressure↗