Search PubMed⌕ Search

Biomedical subjects

S L Lee

Publications and source records attributed to S L Lee.

At least 73 records · Page 4Linked to original sources
PubMed2000

Supplemental oxygen improves resolution of injury-induced pneumothorax.

BACKGROUND/PURPOSE: Traditionally, supplemental oxygen is administered to patients with asymptomatic pneumothorax to accelerate spontaneous resolution. However, this practice is based on models that did not include injury to the visceral pleura and ongoing pleural air leak. This study evaluated the effects of increased inspired oxygen concentration on pneumothorax resolution in a visceral pleural injury model. METHODS: A total of 27 New Zealand white rabbits were divided randomly into 3 groups: room air (RA), 40% FIO2 (40%), and 60% FIO2 (60%). A complete unilateral pneumothorax was created in each animal by a thoracoscopically guided visceral pleural puncture. The animals were then housed in designated oxygen chambers, and observers were blinded to the inspired oxygen concentration. Cross table anteroposterior chest x-rays were obtained preoperatively, postoperatively, and twice a day until the pneumothorax resolved. Time to resolution between the 3 groups was analyzed with 1-way analysis of variance (ANOVA). RESULTS: Twenty of 27 (74%) of the animals completed the study successfully. Mean time to resolution in the RA group (n = 7; 111.2 +/- 30.8 hours) was longer than in the 40% group (n = 6; 71.8 +/- 22.3 hours) and the 60% group (n = 7; 39.4 +/- 14.2 hours). The time to resolution also was longer in the 40% group than in the 60% group. Seven rabbits died before completion of the study of tension pneumothorax (3 of 7) or anesthetic complications (4 of 7). CONCLUSIONS: Supplemental oxygen improves resolution of injury-induced pneumothorax. The tradition of administering supplemental oxygen to patients with asymptomatic pneumothorax should be continued even if there is ongoing pleural air leak.

Animals↗
PubMed2000

Laparoscopic umbilical herniorrhaphy.

BACKGROUND: Laparoscopic technique is an alternative approach to ventral hernia repair. This study evaluated the feasibility of performing umbilical hernia repair using a single 5-mm trocar technique. PATIENTS AND METHODS: During February 1999 to November 1999, we performed laparoscopic umbilical hernia repair in 16 consecutive patients. All operations were performed under general anesthesia. One 5-mm port was used to visualize the defect. A second 5-mm port was inserted only if there was incarcerated omentum requiring reduction. The Endo Close was inserted through a 2-mm incision made directly over the hernia to perform transabdominal closure of the defect using nonabsorbable suture. RESULTS: The mean size of the umbilical hernia defects was 1.2 cm +/- 0.4 (range 1.0-2.0 cm). All operations were completed laparoscopically with no intraoperative or postoperative complications. The mean operative time was 35 +/- 15 minutes (range 21-75 min). All cases were performed in an outpatient setting. There have been no recurrences at a mean follow-up of 5.9 months. CONCLUSIONS: Laparoscopic umbilical herniorrhaphy is safe and technically feasible. Its potential advantages, such as a lower rate of recurrence, will need to be validated with longer follow-up.

Adult↗
PubMed2000

Acute intrauterine infection results in an imbalance between pro- and anti-inflammatory cytokines in the pregnant rabbit.

PROBLEM: Intrauterine infection results in an increase in cytokines. This study compared the time courses for the pro- and anti-inflammatory cytokine responses in 33 pregnant rabbits at 70% gestation. Pro-inflammatory markers were activated nuclear factor-kappa B (NF-kappaB) in placenta and tumor necrosis factor-alpha (TNF-alpha) in amniotic fluid. These were compared to the anti-inflammatory cytokine, interleukin-1 receptor antagonist (IL-1ra), in placenta and uterus. METHOD OF STUDY: Does were endoscopically inoculated with Escherichia coli through their cervices and sacrificed at six intervals between 0 and 30 hr post-inoculation. RESULTS: Activated NF-kappaB, determined by electromobility gel shift assay, increased significantly 16 hr after bacterial inoculation (P < or = 0.05). This was directly mirrored by TNF-alpha concentrations, determined by bioassay, in the amniotic fluid. However, IL-1ra levels, determined by enzyme-linked immunosorbent assay, did not increase in response to infection. CONCLUSIONS: Intrauterine infection results in an imbalance between pro- and anti-inflammatory cytokines that may potentiate infection-induced preterm delivery.

Amniotic Fluid↗
PubMed2000

Tell it like it is.

PROBLEM: Nurses, therapists and case managers were spending too much time each week on the phone waiting to read patient reports to live transcriptionists who would then type the reports for storage in VNSNY's clinical management mainframe database. SOLUTION: A speech recognition system helped solve the problem by providing the staff 24-hour access to an automated transcription service any day of the week. RESULTS: Nurses and case managers no longer wait in long queues to transmit patient reports or to retrieve information from the database. Everything is done automatically within minutes. KEYS TO SUCCESS: VNSNY saved both time and money by updating its transcription strategy. Now nurses can spend more time with patients and less time on the phone transcribing notes. It also means fewer staff members are needed on weekends to do manual transcribing.

Community Health Nursing↗
PubMed1999

Interaction between developmental and cell cycle regulators is required for morphogenesis in Aspergillus nidulans.

In Aspergillus nidulans, mutation of the transcriptional regulator brlA arrests formation of asexual spore-forming structures called conidiophores but does not hinder vegetative hyphal growth. During conidiophore development a 6-fold, brlA-dependent increase in the kinase activities of NIMX(cdc2) and NIMA occurs. A similar level of kinase induction was promoted by ectopic expression of brlA. Northern and Western analysis revealed marked induction of nimX(cdc2) mRNA after ectopic expression of brlA and increased amounts of NIMX(cdc2). Therefore, nimX(cdc2) is developmentally regulated by brlA indicating a direct role for brlA in the regulation of cell cycle genes. That correct regulation of nimX(cdc2) is important for normal development was further supported by analysis of conidiophore development and septation in cell cycle specific mutants. Most noticeably, the nimX(cdc2AF) mutation promoted inappropriate septation and hindered the switch from filamentous growth to budding growth seen during conidiophore development. Therefore, in contrast to the situation previously reported for other multicellular eukaryotes, interaction between developmental regulators and cell cycle regulators is essential for normal morphogenesis in A.nidulans.

Aspergillus nidulans↗
PubMed1999

Characterization of the mUBC9-binding sites required for E2A protein degradation.

Mammalian Ubc9 (mUbc9) is required for rapid degradation of the E2A proteins E12 and E47 by the ubiquitin-proteasome system. We have shown elsewhere that mUbc9 interacts with amino acids 477-530 of E12/E47. Here we test the hypothesis that this region, rich in proline, glutamic acid, serine, and threonine (PEST) residues, serves as the E2A protein degradation domain (DD). An E2A protein lacking this region, E47Delta(478-531), was significantly more stable than wild-type E47(half-life of more than 6 h versus 55 min). Deletion of the E2A DD had no effect on the E-box-binding and transcriptional activity of E47. We mapped two discreet mUbc9-interacting regions within the E2A DD: amino acids 476-494 and 505-513. E2A(505-513) interacted with mUbc9 but not with human Ubc5, MyoD, Id3, or the polymyositis-scleroderma autoantigen. Substitution of the E2A(505-513) central hydrophobic residues with basic residues abolished interaction with mUbc9. Also, full-length E47 lacking the second mUbc9-interacting region was significantly more stable than wild-type E47. Reintroduction of the E2A DD into the long-lived, naturally occurring chimeric oncoprotein E2A-HLF (hepatic leukemic factor) destabilized it, suggesting that this domain can transfer a degradation signal to a heterologous protein. E2A-HLF-DD chimeric protein was stabilized by the proteasome inhibitor LLNL, indicating the role of the ubiquitin-proteasome system mediating degradation through the E2A degradation domain. Our experiments indicate that the E2A DD mediates E2A protein interactions with the ubiquitin-proteasome system and that the E2A DD is required for metabolism of these widely expressed proteins.

3T3 Cells↗
PubMed1999

Expression of mRNAs encoding full-length and truncated TrkB receptors in rat dorsal root ganglia and spinal cord following peripheral inflammation.

Peripheral inflammation induces an increased brain-derived neurotrophic factor (BDNF) synthesis in the dorsal root ganglion (DRG) and an elevated anterograde transport of BDNF to axon terminals in the spinal dorsal horn. To characterize whether expression of trkB is modulated in response to BDNF elevation in these areas, we evaluated changes in expression of full-length and truncated trkB (trkB.FL and trkB.T) mRNAs after injection of complete Freund's adjuvant into the hind paw of the rat. Reverse transcription-polymerase chain reaction analysis revealed that BDNF and trkB.T mRNAs levels in the DRG increased, while no change of expression of trkB.FL mRNA was observed. There was no detectable change in both trkB.FL and trkB.T mRNAs levels in the spinal cord. Considering that trkB.T mRNA is expressed mainly in the perineuronal satellite cells, these results suggest a possible paracrine role of BDNF within the DRG in addition to an important role related with nociception following peripheral inflammation.

Animals↗
PubMed1999

p53 deficiency rescues the adverse effects of telomere loss and cooperates with telomere dysfunction to accelerate carcinogenesis.

Maintenance of telomere length and function is critical for the efficient proliferation of eukaryotic cells. Here, we examine the interactions between telomere dysfunction and p53 in cells and organs of telomerase-deficient mice. Coincident with severe telomere shortening and associated genomic instability, p53 is activated, leading to growth arrest and/or apoptosis. Deletion of p53 significantly attenuated the adverse cellular and organismal effects of telomere dysfunction, but only during the earliest stages of genetic crisis. Correspondingly, the loss of telomere function and p53 deficiency cooperated to initiate the transformation process. Together, these studies establish a key role for p53 in the cellular response to telomere dysfunction in both normal and neoplastic cells, question the significance of crisis as a tumor suppressor mechanism, and identify a biologically relevant stage of advanced crisis, termed genetic catastrophe.

Animals↗
PubMed1999

A study of adult T-cell leukemia/lymphoma incidence in central Brooklyn.

Adult T-cell leukemia/lymphoma (ATL), a rare outcome of infection with human T-lymphotropic virus (HTLV-I), is endemic in central Brooklyn, which has a large Caribbean migrant population. Previous studies have suggested that HTLV-I prevalence in central Brooklyn may be similar to that recorded in the Caribbean islands. We established a pilot 1-year surveillance program to identify cases of ATL in 7 of 10 hospitals serving the residents of 18 zip codes of central Brooklyn with a combined population of 1,184,670. Of the 6,198 in-patient beds in the catchment area, approximately 83% were covered. Twelve incident cases of ATL were ascertained, all among persons of Afro-Caribbean descent, indicating an annual incidence in African-Americans in this community of approximately 3.2/100,000 person-years. Unexplained hypercalcemia was the most useful screening method, identifying 3 of 5 patients not referred for possible ATL by a local hematologist. The female:male ratio was 3:1. The age pattern was different from that reported in the Caribbean Basin and closer to the pattern seen in Japan. Our study supports evidence that HTLV-I infection and ATL are endemic in central Brooklyn and suggests that a more intensive surveillance program for this disease coupled with intervention efforts to reduce HTLV-I transmission are warranted.

Adult↗
PubMed1999

Perihepatic packing of major liver injuries: complications and mortality.

HYPOTHESIS: Perihepatic packs used to control hemorrhage after liver injury increase the risk of complications and this risk increases the longer packs are left in place. DESIGN: Retrospective case series. SETTING: University level I trauma center. PATIENTS: Consecutive patients with hepatic injury. MAIN OUTCOME MEASURES: Liver-related complications (biliary leak and abscess), rebleeding, and mortality. RESULTS: One hundred twenty-nine of 804 patients with liver injuries were treated with perihepatic packing. Of the 69 who survived more than 24 hours, 75% lived to hospital discharge. Mortality rates were 14% and 30% in patients with and without liver complications, respectively (P = .23). Liver complication rates were similar (P = .83) when packs were removed within 36 hours (early [33%]) or between 36 and 72 hours (late [29%]) after they were placed; the rebleeding rate was greater in the early group (21% vs 4%; P<.001). CONCLUSIONS: Liver complications associated with perihepatic packing did not affect survival. Removing liver packs 36 to 72 hours after placement reduced the risk of rebleeding without increasing the risk of liver-related complications.

Adult↗
PubMed1999

Behavioural responses of cockerels to semen collection and their influence on semen characteristics.

One-hundred-and-twenty cockerels of Strain L2 Taiwan Country chicken from the National Chung-Hsing University were tested for their behavioural responses to semen collection at 21 to 30, 34 to 43 and 57 to 66 weeks of age. At every age period, semen was collected from every cockerel 4 times within a 1-week period. 2. Cockerel performances on most semen traits, including volume, concentration, total number of sperm, ease of collection and sensitivity to massage were very consistent within each age period. 3. Males that did not respond nervously to handling or were less sensitive to massage appeared to produce less semen. However, contamination was more serious in males that responded very nervously or were very sensitive to massage. 4. Sensitivity to massage, like semen volume, is an invariant character as indicated by the high correlation between measures taken at different age periods.

Animals↗
PubMed1999

Acute cholecystitis secondary to hemobilia.

Invasive diagnostic and therapeutic techniques such as percutaneous transhepatic cholangiography, endoscopic retrograde cholangiopancreatography (ERCP), transjugular intrahepatic portosystemic shunting, and laparoscopic cholecystectomy have led to a rise in hemobilia. Most complications from hemobilia are attributable to acute blood loss; other complications are secondary to thrombus formation in the biliary tree. We present a case report of acute cholecystitis secondary to hemobilia after percutaneous liver biopsy. The role of ERCP in the diagnosis and treatment of this exceedingly rare event is discussed.

Acute Disease↗
PubMed1999

Too much versus too little: the implications of current iodine intake in the United States.

Iodine intake influences the health of Americans today, but in different ways than it has in the past. In the early 1900s, iodine deficiency was responsible for widespread endemic goiter in the United States. The incidence of goiter was markedly reduced by the introduction of iodine supplementation of salt and other foods in the 1920s. By the middle of this century iodine-related problems in the Unites States were more likely to be associated with too much rather than too little of this essential nutrient. Recent and disturbing new data suggest that there has been a sharp decline in iodine intake during the last 20 years, especially in women of reproductive age. A brief comparison of thyroid response to insufficient and excessive intakes in normal and diseased thyroid tissue is presented. The population affected and the implications for therapy are also reviewed.

Diet Surveys↗
PubMed1999

Serotonin stimulates mitogen-activated protein kinase activity through the formation of superoxide anion.

Our previous studies have shown that, through an active transport process, serotonin (5-HT) rapidly elevates O(-)(2). formation, stimulates protein phosphorylation, and enhances proliferation of bovine pulmonary artery smooth muscle cells (SMCs). We presently show that 1 microM 5-HT also rapidly elevates phosphorylation and activation of the mitogen-activated protein (MAP) kinases extracellular signal-regulated kinase (ERK) 1 and ERK2 of SMCs, and the enhanced phosphorylation is blocked by the antioxidants Tiron, N-acetyl-L-cysteine (NAC), and Ginkgo biloba extract. Inhibition of MAP kinase with PD-98059 failed to block enhanced O(-)(2). formation by 5-HT. Chinese hamster lung fibroblasts (CCL-39 cells), which demonstrate both 5-HT transporter and receptor activity, showed a similar response to 5-HT (i.e., enhanced mitogenesis, O(-)(2). formation, and ERK1 and ERK2 phosphorylation and activation). Unlike SMCs, they also responded to 5-HT receptor agonists. We conclude that downstream signaling of MAP kinase is a generalized cellular response to 5-HT that occurs secondary to O(-)(2). formation and may be initiated by either the 5-HT transporter or receptor depending on the cell type.

1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium ↗
PubMed1999

Reduction of endothelial cell related TGFbeta activity by thiols.

Transforming growth factor beta (TGFbeta) may play an important role in diseases characterized by pulmonary fibrosis. We have previously demonstrated that thiols inhibit the pro-oxidant effects of TGFbeta1 in bovine pulmonary artery endothelial cells (BPAEC). To help define the mechanism of this observation we have examined the effect of reduced (GSH) and oxidized (GSSG) glutathione, N-acetyl cysteine (NAC) and cysteine (CYS) on the biological activity of a) TGFbeta released by bovine pulmonary artery endothelial cells (BPAEC) into culture medium, and b) commercially available porcine platelet TGFbeta1. The biological activity of TGFbeta (following activation) released into the medium from cultured BPAEC was significantly reduced when the cells were cultured in the presence of 10 mM GSH or 10 mM NAC for 24 h (10 mM GSH: 85.7 +/- 50 pg/ml/10(6) cells and 10 mM NAC: 127.3 +/- 35 pg/ml/10(6) cells, compared with control: 541 +/- 8.9 pg/ml/10(6) cells; p < 0.05). Thiols (10 mM GSH, 10 mM NAC and 5 mM cysteine), added directly to cell-free conditioned medium or to a commercially available preparation of porcine platelet TGFbeta1 for 6-24 h had a similar inhibitory effect on the biological activity of TGFbeta and altered the structure of porcine platelet TGFbeta1 as determined by mass spectroscopy. These thiols failed to reduce the expression of TGFbeta mRNA in BPAEC as measured by a competitive polymerase chain reaction assay. Incubating endothelial cells or cell-free conditioned medium with GSSG did not alter the biological activity of TGFbeta. Lower doses of thiols (0.1-1 mM), that we have shown inhibit the antiproliferative and pro-oxidant effects of exogenous TGFbeta1 on BPAEC, had no direct effect on TGFbeta bioactivity. In summary, thiols are capable of reducing the effects of TGFbeta in biological systems through a direct effect on the TGFbeta molecule. However, this action appears to be dose-dependent, and at low doses (0.1-1 mM) thiols may also inhibit the actions of exogenous TGFbeta1 in cell culture through a mechanism involving the cellular redox status.

Acetylcysteine↗