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S L Lee

Publications and source records attributed to S L Lee.

At least 37 records · Page 2Linked to original sources
PubMed2004

Comparison of the fine-scale genetic structure of three dipterocarp species.

We investigated the fine-scale genetic structure of three tropical-rainforest trees, Hopea dryobalanoides, Shorea parvifolia and S. acuminata (Dipterocarpaceae), in Peninsular Malaysia, all of which cooccurred within a 6-ha plot in Pasoh Forest Reserve. A significant genetic structure was found in H. dryobalanoides, weaker (but still significant) genetic structure in S. parvifolia and nonsignificant structure in S. acuminata. Seeds of all three species are wind dispersed, and their flowers are thought to be insect pollinated. The most obvious difference among these species is their height: S. parvifolia and S. acuminata are canopy species, whereas H. dryobalanoides is a subcanopy species. Clear differences were also found among these species in their range of seed dispersal, which depends on the height of the release point; so taller trees disperse their seed more extensively. The estimates of seed dispersal area were consistent with the degree of genetic structure found in the three species. Therefore, tree height probably had a strong influence on the fine-scale genetic structure of the three species.

DNA, Plant↗
PubMed2004

Spatial structure and genetic diversity of two tropical tree species with contrasting breeding systems and different ploidy levels.

Analyses of the spatial distribution pattern, spatial genetic structure and of genetic diversity were carried out in two tropical tree species with contrasting breeding systems and different ploidy levels using a 50-ha demographic plot in a lowland dipterocarp forest in Peninsular Malaysia. Shorea leprosula is a diploid and predominantly outcrossed species, whereas S. ovalis ssp. sericea is an autotetraploid species with apomictic mode of reproduction. Genetic diversity parameters estimated for S. leprosula using microsatellite were consistently higher than using allozyme. In comparisons with S. leprosula and other tropical tree species, S. ovalis ssp. sericea also displayed relatively high levels of genetic diversity. This might be explained by the lower pressure of genetic drift due to tetrasomic inheritance, and for autotetraploids each locus can accommodate up to four different alleles and this allows maintenance of more alleles at individual loci. The observed high levels of genetic diversity in S. ovalis ssp. sericea can also be due to a random retention of more heterogeneous individuals in the past, and the apomictic mode of reproduction might be an evolutionary strategy, which allows the species to maintain high levels of genetic diversity. The spatial distribution pattern analyses of both species showed significant levels of aggregation at small and medium but random distribution at the big diameter-class. The decrease in magnitude of spatial aggregation from small- to large-diameter classes might be due to compensatory mortality during recruitment and survival under competitive thinning process. Spatial genetic structure analyses for both species revealed significant spatial genetic structure for short distances in all the three diameter-classes. The magnitude of spatial genetic structure in both species was observed to be decreasing from smaller- to larger-diameter classes. The high spatial genetic structuring observed in S. ovalis ssp. sericea at the small-diameter class is due primarily to limited seed dispersal and apomictic mode of reproduction. The similar observation in S. leprosula, however, can be explained by limited seed and pollen dispersal, which supports further the fact that the species is pollinated by weak fliers, mainly of Thrips and Megalurothrips in the lowland dipterocarp forest.

Age Factors↗
PubMed2002

Familial dementia with Lewy bodies: clinicopathologic analysis of two kindreds.

Familial cases of dementia with Lewy bodies (DLB) are rare. The authors describe two small kindreds with familial DLB: one with pure DLB meeting consensus criteria for DLB and one with coexistent AD pathology that did not fulfill DLB criteria. The authors call attention to the diverse features of DLB and suggest that current clinical criteria may not detect all cases. Familial DLB is clinically heterogeneous and occurs with or without coexistent AD, suggesting the relevance of LB pathology for the developing dementia.

Aged↗
PubMed2002

Predictors of effective bilateral subthalamic nucleus stimulation for PD.

To identify factors predictive of effective bilateral subthalamic nucleus (STN) stimulation for PD with severe motor complications, pre- and postoperative Unified PD Rating Scale (UPDRS) scores were analyzed in a series of 54 patients who received bilateral STN stimulation. Younger age and levodopa responsiveness predict a favorable response to bilateral STN stimulation. For individual PD symptoms, those that improve with a suprathreshold dose levodopa challenge are likely to improve with stimulation.

Adult↗
PubMed2002

Direct evidence for an intrinsic square vortex lattice in the overdoped high- T(c) superconductor La(1.83)Sr(0.17)CuO(4+delta).

We report here the first direct observations of a well ordered vortex lattice in the bulk of a La(2-x)Sr(x)CuO(4+delta) single crystal (slightly overdoped, x = 0.17). Our small angle neutron scattering investigation of the mixed phase reveals a crossover from triangular to square coordination with increasing magnetic field. The existence of an intrinsic square vortex lattice has never been observed in high-temperature superconductors and is indicative of the coupling of the vortex lattice to a source of anisotropy, such as those provided by a d-wave order parameter or the presence of stripes.

Journal Article↗
PubMed2002

Airway obstruction in children with congenital heart disease: assessment by flexible bronchoscopy.

We assessed the spectrum of airway disorders in children with congenital cardiac anomalies, and reviewed our experience in using flexible bronchoscopy for assessment of airway problems in this patient group. The clinical records, flexible bronchoscopic findings, and cardiac imaging results of pediatric cardiac patients who presented with either clinical or radiological signs of airway obstruction between 1992-1999 were reviewed. Flexible bronchoscopic assessment was performed with the patients under sedation and topical anesthesia, using one of two bronchoscopes, i.e., an Olympus BFN20 or Olympus BF3C20. Of a total of 52 patients, 33 had acyanotic cardiovascular lesions, the commonest being left-to-right shunts (61%), while 19 had cyanotic heart lesions, with right ventricular outflow obstruction being the commonest (63%). Twenty-seven patients had undergone either surgical or transcatheter interventions. The median age at bronchoscopic assessment was 6 months (range, 4 days to 6 years). None of the patients developed significant procedural complications. A definitive diagnosis was made in 48 (92%) patients, 8 of whom had abnormalities involving only the upper airways, 35 only the lower airways, and 5 both. Abnormalities of the upper airway included laryngomalacia (n = 6), subglottic stenosis (n = 3), pharyngeal collapse (n = 2), and 1 each of choanal stenosis and supraglottitis. Extrinsic compression was the commonest lower airway abnormality that was found in 27/40 patients (67%), with a predilection for the left main bronchus (18/27, 67%). The structures that caused extrinsic compression included dilated pulmonary arteries with or without left atrial dilation (n = 20), an anomalous aortic or pulmonary arterial course (n = 3), a dilated aorta (n = 1), and a shunt (n = 1), but were not obvious in 2 patients. Intrinsic lower airway abnormalities included bronchomalacia (n = 4), tracheal stenosis (n = 4), and one each of variant bronchial bifurcation and a pouch arising from the tracheal wall. Intraluminal mucus plugging of the lower airways occurred in the remaining 3 patients. Children with congenital heart disease are at risk of airway obstruction both before and after surgery. Flexible bronchoscopy, being safe and effective in diagnosing airway disorders in this patient group, should be considered as the first line of investigation.

Airway Obstruction↗
PubMed2002

Tracheobronchography and angiocardiography of paediatric cardiac patients with airway disorders.

OBJECTIVE: We report our experience in combining tracheobronchography and angiocardiography in the assessment of a selected cohort of paediatric cardiac patients with problematic airway disorders. METHODOLOGY: The clinical records of 11 patients who underwent 17 studies at a median age of 5.5 months (range 3 months to 10.8 years) were reviewed. Tracheobronchography and angiocardiography were performed under general anaesthesia using a non-ionic contrast agent. The findings were compared with those of flexible bronchoscopy and magnetic resonance imaging (MRI). RESULTS: Seven patients had cardiac lesions associated with vascular anomalies potentially compressing the airway, while four had no identifiable aberrant or enlarged vessels. All examinations but one were performed without complications. Tracheobronchography demonstrated extrinsic vascular compression with secondary airway malacia in three (27%), intrinsic tracheobronchial stenosis in five (45%), and airway malacia in three patients (27%). Precise measurement of the airway calibre and real-time fluoroscopic monitoring facilitated transcatheter tracheobronchial interventions (six balloon dilations, three stent implantations) in four patients. In conjunction with angiocardiography, cine-tracheobronchography provided detailed information on the spatial relationship between vascular and airway structures in all patients; allowed dynamic assessment of airway malacia; and facilitated preoperative planning in six patients. In contrast, bronchoscopy failed to differentiate malacia from extrinsic compression in four patients (36%), while MRI, performed in six patients, was unsatisfactory in one due to a motion artefact and failed to diagnose airway malacia and extrinsic compression in three patients. CONCLUSIONS: Tracheobronchography is relatively safe in paediatric cardiac patients. Combined tracheobronchography and angiocardiography, a less operator-dependent imaging modality compared to bronchoscopy and MRI, delineated the airway and vascular anatomy in detail; facilitated preoperative planning; and permitted transcatheter tracheo-bronchial interventions. The dynamic capability of tracheobronchography supplements that of flexible bronchoscopy and MRI in the diagnosis of airway malacia.

Airway Obstruction↗
PubMed2001

Microchimerism of presumed fetal origin in thyroid specimens from women: a case-control study.

BACKGROUND: Some so-called autoimmune diseases in women might be alloimmune and represent a chronic graft-versus-host response attributable to transplacentally acquired fetal cells. Thyroid disease is more common in women than men, and post partum exacerbation of thyroiditis is common. Our aim was to investigate whether there is an association between fetal cell microchimerism and thyroid disease in women. METHODS: Surgical specimens were obtained from 29 women who underwent thyroidectomy for various thyroid disorders. Control specimens were taken from clinically and histologically normal thyroids obtained at necropsy from eight women who died from unrelated conditions. Medical records and pregnancy histories were reviewed. Fluorescence in-situ hybridisation analysis was done with probes specific for X and Y chromosomes. Slides were examined with a fluorescence microscope to detect the presence of male cells-with one X and one Y signal in the nucleus-among maternal cells containing two X signals. FINDINGS: Male cells were seen in thyroid sections from 16 patients but not in those from controls (p=0.01). Male cells (1-165 per slide) were seen individually or in clusters in all thyroid diseases and were not restricted to inflammatory thyroid diseases. In one patient with a progressively enlarging goitre, we noted fully differentiated male thyroid follicles closely attached to and indistinguishable from the rest of the thyroid. INTERPRETATION: Our findings suggest a relation between fetal cell microchimerism and thyroid disease. Furthermore, fetal stem cells might be capable of differentiation into mature thyroid follicles in their mothers with favourable environmental and developmental factors.

Adult↗
PubMed2001

Synthesis and evaluation of the sunflower derived trypsin inhibitor as a potent inhibitor of the type II transmembrane serine protease, matriptase.

We report here the synthesis of a 14-amino acid long bicyclic peptide, previously isolated from sunflower seeds. This peptide, termed sunflower trypsin inhibitor (SFTI-1), is one of the most potent naturally occurring small-molecule trypsin inhibitors. In addition to inhibiting trypsin, the synthetic SFTI-1 is also a very potent inhibitor, with a K(i) of 0.92nM, of the recently identified epithelial serine protease, termed 'matriptase'.

Amino Acid Sequence↗
PubMed2001

Structure-based approach for the discovery of bis-benzamidines as novel inhibitors of matriptase.

Matriptase, a trypsin-like serine protease, which may be involved in tissue remodeling, cancer invasion, and metastasis. Potent and selective matriptase inhibitors not only would be useful pharmacological tools for further elucidation of the role of matriptase in these processes but also could have therapeutic potential for the treatment and/or prevention of cancers. We report herein the structure-based approach for the discovery of bis-benzamidines as a novel class of potent matriptase inhibitors. The lead compound, hexamidine (1), inhibits not only the proteolytic activity of matriptase, (K(i) = 924 nM) but also of thrombin K(i) = 224 nM). By testing several available analogues, we identified a new analogue (7) that has a K(i) = 208 nM against matriptase and has only weak inhibitory activity against thrombin (K(i) = 2670 nM), thus displaying a 13-fold selectivity toward matriptase. Our results demonstrated that structure-based database screening is effective in the discovery of matriptase inhibitors and that bis-benzamidines represent a class of promising matriptase inhibitors that can be used for further drug design studies. Finally, our study suggested that there is sufficient structural differences between matriptase and its closely related serine proteases, such as thrombin, for the design of potent and selective matriptase inhibitors.

Benzamidines↗
PubMed2001

Computed tomography and ultrasonography do not improve and may delay the diagnosis and treatment of acute appendicitis.

HYPOTHESIS: Computed tomography (CT) and ultrasonography (US) do not improve the overall diagnostic accuracy for acute appendicitis. DESIGN: Retrospective review. SETTING: University tertiary care center. PATIENTS: Seven hundred sixty-six consecutive patients undergoing appendectomy for suspected appendicitis from January 1, 1995, to December 31, 1999. MAIN OUTCOME MEASURES: Epidemiology of acute appendicitis and the roles of clinical assessment, CT, US, and laparoscopy. RESULTS: The negative appendectomy rate was 15.7%, and the incidence of perforated appendicitis was 14.6%. A history of migratory pain had the highest positive predictive value (91%), followed by leukocytosis greater than 12 x 10(9)/L (90.1%), CT (83.8%), and US (81.3%). The false-negative rates were 60% for CT and 76.1% for US. Emergency department evaluation took a mean +/- SD of 5.2 +/- 5.4 hours and was prolonged by US or CT (6.4 +/- 7.4 h and 7.8 +/- 10.8 h, respectively). The duration of emergency department evaluation did not affect the perforation rate, but patients with postoperative complications had longer evaluations (mean +/- SD, 8.0 +/- 12.7 h) than did those without (4.8 +/- 3.3 h) (P =.04). Morbidity was 9.1%, 6.4% for nonperforated cases and 19.8% for perforated cases. Seventy-six patients had laparoscopic appendectomy, with a negative appendectomy rate of 42.1%, compared with 15.4% for open appendectomy (P<.001). Laparoscopy, however, had minimal morbidity (1.3%) and correctly identified the abnormality in 91.6% of patients who had a normal-appearing appendix. CONCLUSIONS: Migratory pain, physical examination, and initial leukocytosis remain reliable and accurate in diagnosing acute appendicitis. Neither CT nor US improves the diagnostic accuracy or the negative appendectomy rate; in fact, they may delay surgical consultation and appendectomy. In atypical cases, one should consider the selective use of diagnostic laparoscopy instead.

Acute Disease↗
PubMed2001

Hypothermia induces T-cell production of immunosuppressive cytokines.

BACKGROUND: Hypothermia is associated with increased postoperative infectious complications. We hypothesized that hypothermia suppresses the inflammatory response by altering T-cell cytokine production from a proinflammatory to an antiinflammatory profile, thus explaining the increased susceptibility to infectious complications associated with perioperative hypothermia. METHODS: Forty rats were randomized to either a Hypothermia (30 degrees C) or Control (38 degrees C) group. Blood samples taken at baseline and after 8 h of thermoregulation were stimulated with phorbol 12-myristate 13-acetate and ionomycin. Interleukin (IL)-2 receptor expression and intracellular IL-10 production were measured using monoclonal antibodies and flow cytometry in CD4 and CD8 T cells. Differences in IL-10 production and IL-2 receptor expression for stimulated samples in the Hypothermia and Control groups were compared. RESULTS: Stimulated CD4 cells demonstrated an antiinflammatory cytokine expression profile after hypothermia. Intracellular IL-10 production increased in the Hypothermia group but remained the same in the Control group (% change = 40 [3,87] and 2 [-36,26], respectively; P = 0.043). The increase in IL-2 receptor expression observed in the control group was suppressed after hypothermia (% change = 12[8,30] and 1 [-3,13], respectively; P = 0.026). We observed a greater increase in IL-10 production by CD8 cells from hypothermic animals than in those from control animals (% change = 41 [-8,90] and -4 [-40,5], respectively; P = 0.019). CD8 IL-2 receptor expression in hypothermic animals was similar to that of control animals (% change = 23 [-7,37] vs 25 [2,80], respectively; P = 0.32). CONCLUSIONS: Hypothermia induced an antiinflammatory T-cell cytokine profile.

Animals↗
PubMed2001

Hepatic inflammatory pseudotumor: case report, review of the literature, and a proposal for morphologic classification.

Inflammatory pseudotumors (IPT) are uncommon mass lesions arising most typically in the lungs of young adults. These tumors are so named because of the difficulty in distinguishing them preoperatively from malignant lesions. IPT are characterized histologically by localized fibrous proliferations with infiltration by mononuclear leukocytes, particularly plasma cells. Seventeen previous cases of IPT involving the liver and biliary tree have been reported in children. In this location, IPT may lead to biliary obstruction, portal hypertension, cirrhosis and eventually hepatic failure. We describe the youngest patient ever reported with hepatic IPT (HIPT) and biliary obstruction, who was successfully managed with a left hepatic lobectomy and Kasai portoenterostomy. Based on all previous cases of HIPT in both adults and children (74 cases), we propose a morphologic classification of these lesions based on the presence of single versus multiple lesions, with individualized management. Type 1 lesions are large, solitary lesions, often with central necrosis, giving a characteristic radiographic appearance. Type 2 lesions are multiple smaller, solid nodules indistinguishable from metastatic malignancy.

Granuloma, Plasma Cell↗
PubMed2001

Comparison of pulmonary function and postoperative pain after laparoscopic versus open gastric bypass: a randomized trial.

BACKGROUND: Impairment of pulmonary function is common after upper abdominal operations. The purpose of this study was to compare postoperative pulmonary function and analgesic requirements in patients undergoing either laparoscopic or open Roux-en-Y gastric bypass (GBP). STUDY DESIGN: Seventy patients with a body mass index of 40 to 60 kg/m2 were randomly assigned to undergo laparoscopic (n = 36) or open (n = 34) GBP. The two groups were similar in age, gender, body mass index, pulmonary history, and baseline pulmonary function. Pulmonary function studies were performed preoperatively and on postoperative days 1, 2, 3, and 7. Oxygen saturation and chest radiographs were performed on both groups preoperatively and on postoperative day 1. Postoperative pain was evaluated using a visual analog scale and the amount of narcotic consumed was recorded. Data are presented as mean +/- standard deviation. RESULTS: Laparoscopic GBP patients had significantly less impairment of pulmonary function than open GBP patients on the first three postoperative days (p < 0.05). By the 7th postoperative day, all pulmonary function parameters in the laparoscopic GBP group had returned to within preoperative levels, but only one parameter (peak expiratory flow) had returned to preoperative levels in the open GBP group. On the first postoperative day, laparoscopic GBP patients used less morphine than open GBP patients (46 +/- 31 mg versus 76 +/- 39 mg, respectively, p < 0.001), and visual analog scale pain scores at rest and during mobilization were lower after laparoscopic GBP than after open GBP (p < 0.05). Fewer patients after laparoscopic GBP than after open GBP developed hypoxemia (31% versus 76%, p < 0.001) and segmental atelectasis (6% versus 55%, p = 0.003). CONCLUSION: Laparoscopic gastric bypass resulted in less postoperative suppression of pulmonary function, decreased pain, improved oxygenation, and less atelectasis than open gastric bypass.

Adult↗
PubMed2001

Advancement flap umbilicoplasty after abdominal wall closure: postoperative results compared with normal umbilical anatomy.

BACKGROUND/PURPOSE: Umbilical reconstruction frequently is an adjunct used after repair of congenital abdominal wall defects. The authors describe a new technique of umbilicoplasty and compare their results with normal neonatal umbilical anatomy. METHODS: After fascial closure, 6 newborn infants with either gastroschisis (n = 3) or omphalocele (n = 3) underwent umbilicoplasty performed by advancing bilateral skin flaps including creation of an umbilical skin collar. The umbilical collar height, circumference, and distance from the xiphoid with respect to the pubis (ratio of xiphoid-umbilicus distance to xiphoid-pubis distance or XU:XP) were recorded and referenced to normal umbilical anatomy in additional 28 infants (24 to 40 weeks gestation [mean, 33.2 weeks] and age 2 to 131 days [mean, 26.5 days]). RESULTS: After umbilicoplasty, all infants had a near-normal-appearing umbilicus (collar height, 0.75 +/- 0.25 cm and circumference, 5.24 +/- 1.20 cm) compared with normal umbilical anatomy (collar height, 4.36 +/- 1.32 cm and circumference, 1.03 +/- 0.38 cm). However, after umbilicoplasty, the neoumbilicus was positioned more cephalad (XU:XP = 0.53 +/-.05) compared with normal (mean XU:XP, 0.67 +/- 0.07). The only complication encountered was a small dehiscence of the superior aspect of the abdominal wound. CONCLUSIONS: Closure of abdominal wall defects with simultaneous umbilicoplasty provides a cosmetically pleasing result. When performing umbilicoplasty, attempt should be made to position the neoumbilicus as inferior as possible, optimally at two thirds the distance from the xiphoid to the pubis.

Abdominal Muscles↗
PubMed2001

Functional outcome of new blood vessel growth into ischemic skeletal muscle.

PURPOSE: The administration of angiogenic growth factors and the transfer of well-vascularized tissues have been shown to induce development of new blood vessels in ischemic muscle. The functional significance of these new vessels is unknown. The hypothesis of this study is that the transfer of vascularized muscle and the local infusion of basic fibroblast growth factor (bFGF) synergistically improve contractile function of ischemic skeletal muscle. METHODS: Twenty-six rabbits were divided into four groups. An ischemic hindlimb was created in each by ligating the right common iliac artery. The flap + bFGF group (n = 6) had transposition of a contralateral rectus muscle flap onto the thigh. Additionally, bFGF (3 ng/h) was continuously infused at the flap-thigh interface. In the flap group (n = 6), a similar muscle flap was created, but carrier solution was infused at the interface. In the bFGF group (n = 6), no muscle flap was created; instead, bFGF (3 ng/h) was infused into the external iliac artery of the ischemic limb. In the control group (n = 8), carrier solution was infused into the external iliac artery (no flap, no bFGF). After 1 week, the soleus muscle was isolated and stimulated. Maximum twitch tension, the fatigue index (force of contraction after 2 minutes of continuous stimulation/initial force of contraction), maximum recovery, and the number of limbs recovered (ie, limbs that achieve a force of contraction during the recovery period of > 75% of the force of the initial contraction at the start of continuous stimulation) were recorded. Blood vessel density (number of vessels per ***) was determined by immunostaining the soleus muscle with anti-alpha-actin antibody. RESULTS: All values were indexed to the contralateral normal limb. The flap + bFGF group showed significant improvement versus the control group in maximum twitch tension (1.07 +/- 0.13 vs 0.63 +/- 0.12, P < .05), maximum recovery (0.94 +/- 0.05 vs 0.58 +/- 0.05, P < .05), and the number of limbs recovered (5/5 vs 0/6, P < .05). This improved function correlated with increased vessel density (flap + bFGF group, 1.44 +/- 0.11 vs control group, 0.72 +/- 0.01, P < .05). CONCLUSION: Reperfusion of an ischemic limb with a well-vascularized muscle flap and local bFGF infusion promoted increased blood vessel density in distal ischemic muscle. This increased vascularity was associated with restoration of otherwise impaired muscle function. Improved function occurred rapidly (1 week). A transposed muscle flap provided a functional blood supply to the site of maximum ischemia; this could be used to salvage otherwise nonreconstructible ischemic limbs.

Angiogenesis Inducing Agents↗