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Biomedical subjects

D I Lee

Publications and source records attributed to D I Lee.

17 recordsLinked to original sources
PubMed2004

Laparoscopic radical prostatectomy: review and assessment of an emerging technique.

BACKGROUND: Several recent reports have affirmed the feasibility of the laparoscopic approach for radical prostatectomy. In this review, we discuss the morbidities associated with this technique and compare outcomes and convalescence with standard open radical prostatectomy. METHODS: We reviewed all currently published data on laparoscopic radical prostatectomy and our series of 45 robotic-assisted radical prostatectomies and compared them to several landmark series of open retropubic and perineal radical prostatectomies. RESULTS: Although the initial series reported long operating times, these times have been significantly reduced in more recent series. Data on blood loss, convalescence, impotence, and incontinence rates have also been promising. CONCLUSIONS: Although follow-up has been short thus far, laparoscopic radical prostatectomy has been shown to be similar to open radical prostatectomy in several areas.

Humans↗
PubMed2003

Nitrification of high strength ammonia wastewater and nitrite accumulation characteristics.

Biological nitrogen removal via the nitrite pathway in wastewater treatment is very important in saving the cost of aeration and as an electron donor for denitrification. Wastewater nitrification and nitrite accumulation were carried out in a biofilm airlift reactor with autotrophic nitrifying biofilm. The biofilm reactor showed almost complete nitrification and most of the oxidized ammonium was present as nitrite at the ammonium load of 1.5 to 3.5 kg N/m3 x d. Nitrite accumulation was stably achieved by the selective inhibition of nitrite oxidizers with free ammonia and dissolved oxygen limitation. Stable 100% conversion to nitrite could also be achieved even under the absence of free ammonia inhibition on nitrite oxidizers. Batch ammonium oxidation and nitrite oxidation with nitrite accumulating nitrifying biofilm showed that nitrite oxidation was completely inhibited when free ammonia is higher than 0.2 mg N/L. However, nitrite oxidation activity was recovered as soon as the free ammonia concentration was below the threshold level when dissolved oxygen concentration was not the limiting factor. Fluorescence in situ hybridization analysis of cryosectioned nitrite accumulating nitrifying biofilm showed that the beta-subclass of Proteobacteria, where ammonia oxidizers belong, was distributed outside the biofilm whereas the alpha-subclass of Proteobacteria, where nitrite oxidizers belong, was found mainly in the inner part of the biofilm. It is likely that dissolved oxygen deficiency or limitation in the inner part of the nitrifying biofilm, where nitrite oxidizers exist, is responsible for the complete shut down of the nitrite oxidizers activity under the absence of free ammonia inhibition.

Ammonia↗
PubMed2001

Intraoperative mild hypothermia does not increase the plasma concentration of stress hormones during neurosurgery.

PURPOSE: To determine how mild hypothermia (34 degrees C) affects the hemodynamic and the stress hormonal responses intraoperatively and during extubation in patients undergoing cerebral aneurysm surgery. METHODS: After induction, anesthesia was maintained with 1.2% isoflurane and 50% nitrous oxide. For the normothermia and the hypothermia groups, the body temperature was maintained at 36.9 +/- 0.3 degrees C and 34.2 +/- 0.2 degrees C respectively up to the recovery room. Hemodynamic changes were recorded continuously. Stress hormones comprising epinephrine, norepinephrine, ADH, ACTH, and cortisol were measured at the awake control, intraoperative, and extubation periods. RESULTS: Vital signs of the intraoperative and postextubation time periods were not significantly different between the normothermia and hypothermia groups except for a statistically lower pulse rate intraoperatively in the hypothermia group (P <0.05). In the control awake state, all five hormonal concentrations were similar between the two groups. Intraoperatively, all of the hormonal levels tended to be lower in the hypothermia group compared to the normothermia group, but only the epinephrine level decreased sufficiently to reach statistical significance (P <0.05). During extubation, all stress hormone concentrations, except norepinephrine, were lower in the hypothermia group (epinephrine: P <0.05; ADH: P <0.05; ACTH: P <0.05; cortisol: P <0.05). CONCLUSIONS: Our data suggest that intraoperative mild hypothermia neither significantly affects the blood pressure response nor increases the concentrations of stress hormones intraoperatively. Furthermore, mild hypothermia significantly decreased the plasma concentrations of stress hormones during the extubation period.

Adrenocorticotropic Hormone↗
PubMed2001

Flail aortic valve and acute aortic regurgitation due to spontaneous localized intimal tear of ascending aorta.

This report describes the transesophageal echocardiographic findings of acute severe aortic regurgitation resulting from localized transverse intimal tear of ascending thoracic aorta which could not be suspected as a cause of flail aortic valve preoperatively. In patients with chest pain and acute aortic regurgitation associated with flail aortic valve, localized intimal tear of aorta should be considered as a possible cause of flail aortic valve.

Aortic Rupture↗
PubMed2001

Experience with endoluminal ultrasonography in the urinary tract.

Ultrasonography has been an invaluable tool in the field of urology for its noninvasiveness, safety, and relatively low cost. However, examination of the ureter with ultrasound is difficult because of the distance of the transducer from the ureter and because of intervening structures such as nonconductive bowel gas. As smaller probes have become available, attempts have been made to apply them to endoluminal use. Endoluminal ultrasonography has been employed in urology to examine the proper placement of injected collagen, diagnose urethral diverticula, diagnose and stage upper tract transitional-cell carcinoma, locate crossing vessels to guide endopyelotomy, diagnose submucosal calculi, and examine the severity and length of ureteral strictures.

Collagen↗
PubMed2001

Long-term effects of ureteroscopic laser lithotripsy on glomerular filtration rate in the face of mild to moderate renal insufficiency.

BACKGROUND AND PURPOSE: Ureteroscopic laser treatment of calculi in the upper urinary tract was examined in regard to its effect on renal function in the setting of mild renal insufficiency. Percutaneous nephrolithotomy (PCNL) and SWL have been previously shown not to adversely affect the glomerular filtration rate (GFR) in renal insufficiency, but to our knowledge, the effect of ureteroscopic laser lithotripsy on GFR has not been previously reported. PATIENTS AND METHODS: A retrospective review of all cases of ureteroscopic laser lithotripsy at our institution was performed. A total of 18 patients with a baseline serum creatinine of > or = 1.5 mg/dL were found. The mean follow-up after treatment was 18.0 months (range 4-39 months). The change in the reciprocal of serum creatinine was used as an indicator of change in the GFR. Deterioration of 20% was considered significant. RESULTS: The overall mean change in treated patients was a 5.9% improvement. Patients with a preoperative creatinine of < 2.0 mg/dL improved 7.6% and those with creatinine of > or = 2.0 mg/dL increased 3.9%. Other factors such as the size of the stone, location of the stone, and total joules used during treatment were not significant. CONCLUSION: This examination suggests that ureteroscopic laser lithotripsy has no ill effects on renal function in the face of mild to moderate renal insufficiency.

Adult↗
PubMed2001

Muc1 mucins on the cell surface are adhesion sites for Pseudomonas aeruginosa.

Recently, we cloned and characterized a full-length cDNA of the hamster Muc1 gene, the expression of which appears to be associated with secretory cell differentiation (Park HR, Hyun SW, and Kim KC. Am J Respir Cell Mol Biol 15: 237-244, 1996). The role of Muc1 mucins in the airway, however, is unknown. In this study, we investigated whether cell surface mucins are adhesion sites for Pseudomonas aeruginosa. Chinese hamster ovary (CHO) cells not normally expressing Muc1 mucin were stably transfected with the hamster Muc1 cDNA, and binding to P. aeruginosa was examined. Our results showed that 1) stably transfected CHO cells expressed both Muc1 mRNA and Muc1 mucins based on Northern and Western blot analyses, 2) Muc1 mucins present on the cell surface were degraded by neutrophil elastase, and 3) expression of Muc1 mucins on the cell surface resulted in a significant increase in adhesion of P. aeruginosa that was completely abolished by either proteolytic cleavage with neutrophil elastase or deletion of the extracellular domain by mutation. We conclude that Muc1 mucins expressed on the surface of CHO cells serve as adhesion sites for P. aeruginosa, suggesting a possible role for these glycoproteins in the early stage of airway infection and providing a model system for studying epithelial cell responses to bacterial adhesion that leads to airway inflammation in general and cystic fibrosis in particular.

Animals↗
PubMed2000

The effects of morphine on blood-brain barrier disruption caused by intracarotid injection of hyperosmolar mannitol in rats.

UNLABELLED: This study was performed to evaluate whether morphine could alter the degree of disruption of the blood-brain barrier (BBB) caused by hyperosmolar mannitol. Under isoflurane anesthesia, rats in a control group were infused with 25% mannitol into the internal carotid artery before measuring the transfer coefficient (Ki) of (14)C-alpha-aminoisobutyric acid. Infusion of morphine 3 mg/kg in the small-dose morphine group and 10 mg/kg in the large-dose morphine group was completed, 10 min before administering mannitol. There were no statistical differences in systemic blood pressures between these three groups of animals. In the control group, the Ki of the ipsilateral cortex where mannitol was injected, increased to 4.6 times that of the contralateral cortex (19.5 +/- 8.5 vs 4.2 +/- 1.2 microL. g(-1). min(-1), P < 0.002). The Ki of the ipsilateral cortex of the small-dose morphine group was 13.5 +/- 7.6 microL. g(-1). min(-1). The Ki of the ipsilateral cortex of the large-dose morphine group was 9.2 +/- 4.5 microL. g(-1). min(-1) and was smaller than that of control animals (P < 0.05). There was no significant difference in the Ki of the contralateral cortex among the three groups. In conclusion, morphine attenuated BBB disruption induced by hyperosmolar solution without significant effects on systemic blood pressure. IMPLICATIONS: Our study suggests that morphine may be effective in reducing the blood-brain barrier disruption by hyperosmolar mannitol without significant effects on systemic blood pressure.

Analgesics, Opioid↗
PubMed1998

Transesophageal echocardiographic identification of left upper pulmonary venous obstruction caused by compression by spontaneous pseudoaneurysm of the descending thoracic aorta.

Pseudoaneurysm of the aorta usually occurs as a complication of nonpenetrating trauma or deceleration injuries. Spontaneous pseudoaneurysm of the aorta is, however, extremely rare. Pulmonary veins can be affected in this situation because of the anatomic proximity. However, it is often overlooked during clinical examination, during routine echocardiography, and even at invasive angiography. This report describes the importance of transesophageal echocardiography in the detection of pulmonary vein compression, which is not suspected during other noninvasive and invasive diagnostic tests, in a patient with spontaneous pseudoaneurysm of the descending thoracic aorta.

Adult↗
PubMed1998

Identification and characterization of high molecular-mass mucin-like glycoproteins in the plasma membrane of airway epithelial cells.

A previous lectin binding study demonstrated the presence of high molecular-mass mucin-like glycoproteins (HMGP) on the surface of hamster tracheal surface epithelial (HTSE) secretory cells (Proc. Natl. Acad. Sci. USA 1987;84:9304). In the present study, we intended to isolate and characterize these HMGP from the plasma membrane of the primary HTSE cells and then to determine whether or not these membrane HMGP are Muc-1 mucins, a type of mucins originally discovered on the surface of some carcinomas. A subcellular fraction enriched with the plasma membrane was obtained using a sucrose density gradient centrifugation. This fraction contained high molecular-mass glycoconjugates which were excluded from Sepharose CL-4B gel. Biochemical characterization of these glycoconjugates revealed the following characteristics: (1) susceptibility to both pronase and mild alkaline treatments, but totally resistant to proteoglycan-digesting enzymes; (2) partitioning in the detergent phase of Triton X-114 and resistance to digestion by phosphatidylinositol phospholipase C or D; (3) a buoyant density of 1.5 g/ml based on CsCl density gradient centrifugation; (4) polydispersity in terms of both size and charge density; and (5) lack of immunoreactivity with an anti-Muc-1 mucin antibody. We conclude that the plasma membrane of HTSE cells at confluence contains HMGP, which seem to be the integral membrane proteins but different from Muc-1 mucins, and that these membrane HMGP appear to share some similarities with secreted mucins in terms of size and charge.

Animals↗
PubMed1996

Cloning and characterization of cDNAs coding for heavy and light chains of a monoclonal antibody (MabA34) specific for human plasma apolipoprotein A-I.

We have determined the nucleotide (nt) sequences encoding the heavy (H)- and light (L)-chains of the Fab fragment of a murine monoclonal antibody, MabA34 (gamma1, kappa), which is specific for human plasma apolipoprotein A-I of high-density lipoproteins. The variable (V) regions of the H- and L-chains were revealed to be members of mouse H-chain subgroup II(A) and kappa L-chain subgroup II, respectively. A few unusual amino acids in the V region of the H-chain, and nt residues probably introduced by somatic mutations from germline genes were also identified.

Amino Acid Sequence↗
PubMed1996

Cloning and characterization of cDNAs coding for heavy and light chains of a monoclonal antibody (MabB23) specific for human plasma apolipoprotein B-100.

We have determined the nucleotide sequences encoding the heavy and light chains of the Fab fragment of murine monoclonal antibody MabB23(gamma2b,lambda), which is specific for human plasma apolipoprotein B-100 of low-density lipoproteins. The sequence analyses revealed that the variable regions of the heavy and light chains are members of mouse heavy-chain subgroup I(B) and lambda light-chain, respectively. A few unusual amino acids in the framework and constant regions of the heavy-chain were also noticed.

Amino Acid Sequence↗
PubMed1990

Species-specific oligodeoxynucleotide probes for the identification of periodontal bacteria.

Oligodeoxynucleotide probes were developed for identification of the periodontal bacteria Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, B. intermedius types I and II, B. forsythus, Eikenella corrodens, Fusobacterium nucleatum, Haemophilus aphrophilus, Streptococcus intermedius, and Wolinella recta. Probes were designed by sequencing the 16S rRNA for each bacterium, identifying hypervariable regions, and chemically synthesizing species-specific probes. These probes were specific when tested against a panel of nucleic acids from closely related bacteria.

Bacteria↗
PubMed1989

Restricted degradation of U6 RNA in a nuclear extract of Ehrlich ascites tumor cells.

A new nucleolytic activity that causes restricted digestion of U6 RNA was found in a nuclear extract of Ehrlich ascites tumor cells. This nucleolytic activity specifically degrades U6 RNA in the vicinity of its 3'-end with accumulation of a discrete sized degradation product of RNA of 90-95 nucleotides. Since this degradation product was not digested further by the nuclease under these conditions, this trimming of U6 RNA is supposed to be a biologically meaningful reaction. This nucleolytic activity required Mg2+, and was inhibited by Zn2+ or Ca2+.

Animals↗
PubMed1988

Uridylation of U6 RNA in a nuclear extract in Ehrlich ascites tumor cells.

The uridylation of U6 RNA in a nuclear extract of Ehrlich ascites tumor cells was examined. This reaction required ATP or GTP, although these nucleotides were not incorporated into U6 RNA itself. ATP and GTP could be replaced by their nonhydrolyzable analogues ATP gamma S and GTP gamma S. Therefore, hydrolysis of ATP or GTP is not necessary for the uridylation of U6 RNA, indicating that these nucleotides are effectors of this reaction. By chromatographies of a nuclear extract of Ehrlich ascites tumor cells on phosphocellulose and DEAE-cellulose, U6 RNA could be separated from an enzyme adding a uridine residue(s) to this RNA.

Adenosine Triphosphate↗