Biomedical subjects

S B Lee

Publications and source records attributed to S B Lee.

At least 109 records · Page 6Linked to original sources

PubMed1997

Enhanced expression of CD14 antigen on myeloid lineage cells derived from the bone marrow of patients with severe rheumatoid arthritis.

OBJECTIVE: We previously reported the accumulation of abnormal myeloid cell populations reacting with CD14 (MY4) monoclonal antibody in the iliac and epiphyseal bone marrow of patients with severe rheumatoid arthritis (RA). Therefore, we investigated in vitro production and modulation of CD14+ myeloid cells from iliac bone marrow cells. METHODS: Mononuclear cells were prepared from iliac bone marrow aspirates from patients with RA. The presence of unusual myeloid cells was assessed by 2 color flow cytometry of cells cultured under various conditions. RESULTS: Cultured iliac bone marrow cells of patients with severe RA produced 14.7% of CD14+ CD15+ cells on average. Cultures derived from healthy donors and from patients with a milder form of RA produced fewer CD14+ CD15+ cells (< 10%). The production of CD14+ CD15+ cells was enhanced by granulocyte macrophage colony stimulating factor and interleukin 1beta, but inhibited by T lymphocytes. CONCLUSION: Production and modulation of CD14+ myeloid cells were observed in iliac bone marrow of patients with severe RA.

Adult↗

PubMed1997

Osteoclastogenesis in iliac bone marrow of patients with rheumatoid arthritis.

OBJECTIVE: To investigate osteoclastogenesis in bone marrow cells from patients with various pathogenic backgrounds known to induce osteoporosis, to identify specific factors that may cause generalized osteoporosis in patients with rheumatoid arthritis (RA). METHODS: Bone marrow blood was obtained from 59 women, 36 with RA and 23 without RA. Patients with RA were classified as severe (26) and mild RA (10: 5 patients with and 5 without corticosteroid therapy). The non-RA subjects were divided into 3 groups, premenopausal (7), menopausal (8), and elderly (8). As a marker of bone resorption, the pyridinoline crosslinked telopeptide domain of type I collagen (ICTP) concentration in the bone marrow supernatant was measured by radioimmunoassay. The bone marrow cells were cultured 14 days in the presence or absence of autologous bone marrow supernatant; then the number of tartrate resistant acid phosphatase positive multinucleated cells (TRAP positive MNC) was counted as an indicator of osteoclastogenesis. RESULTS: ICTP concentration of the bone marrow supernatant and the number of TRAP positive MNC showed remarkable enhancement in some patients with severe RA, but these features were not observed in the 3 control groups. CONCLUSION: Increased bone resorption and enhanced osteoclastogenesis were specifically observed in the iliac bone marrow of patients with RA, especially those with severe RA. These phenomena can be considered to accompany generalized osteoporosis in RA.

Adult↗

PubMed1996

Decreased expression of phospholipase C-beta 2 isozyme in human platelets with impaired function.

Platelets from a patient with a mild inherited bleeding disorder and abnormal platelet aggregation and secretion show reduced generation of inositol 1,4,5-trisphosphate, mobilization of intracellular Ca2+, and phosphorylation of pleckstrin in response to several G protein mediated agonists, suggesting a possible defect at the level of phospholipase C (PLC) activation (see accompanying report). A procedure was developed that allows quantitation of platelet PLC isozymes. After fractionation of platelet extracts by high-performance liquid chromatography, 7 out of 10 known PLC isoforms were detected by immunoblot analysis. The amount of these isoforms in normal platelets decreased in the order PLC-gamma 2 > PLC-beta 2 > PLC-beta 3 > PLC-beta 1 > PLC-gamma 1 > PLC-delta 1 > PLC-beta 4. Compared with normal platelets, platelets from the patient contained approximately one-third the amount of PLC-beta 2, whereas PLC-beta 4 was increased threefold. These results suggest that the impaired platelet function in the patient in response to multiple G protein mediated agonists is attributable to a deficiency of PLC-beta 2. They document for the first time a specific PLC isozyme deficiency in human platelets and provide an unique opportunity to understand the role of different PLC isozymes in normal platelet function.

Blood Platelets↗

PubMed1996

Effect of amino acid residues at the cleavable site of substrates on the remarkable activation of thermolysin by salts.

The activity of thermolysin in the hydrolysis of N-[3-(2-furyl)acryloyl]-glycyl-L-leucine amide and N-carbobenzoxy-L-aspartyl-L-phenylalanine methyl ester is remarkably enhanced in the presence of high concentrations (1-5 M) of neutral salts [Inouye (1992) J. Biochem. (Tokyo) 112, 335-340]. In this study, the effect of salts on such activity has been examined using a series of substrates, furylacryloyl dipeptide amides, which have various hydrophobic amino acids at the cleavable bond. Although the enzyme activity varies widely depending on the substrate employed, the degree of activation at a given concentration of NaCl is considerably similar. This indicates that the degree of activation is not dependent on the hydrophobicity of the amino acid side chains at the scissile bond of the substrates. The molecular activity, kcat, and Michaelis constant, Km, were evaluated separately for substrates N[3-(2-furyl)acryloyl]-L-leucyl-L-alanine amide and N-[3-(2-furyl)acryloyl]L-phenyl-alanyl-L-alanine amide, and the activation was found to be brought about only by an increase in k(cat'). The effectiveness of monovalent cations on the increase of k(cat) was determined to follow the order of Na(+)>K(+)>Li(+).

Amides↗

PubMed1996

Intrathecal administration of sodium nitroprusside, a nitric oxide donor, increases blood pressure in anesthetized rats.

The present study was performed to investigate the role of spinal nitric oxide (NO) in the central regulation of blood pressure (BP). Experiments were carried out in anesthetized artificially ventilated male Wistar rats. Intrathecal (i.t.) administration of drugs was made at the thoracic spinal level. I.t. injection of a NO donor, sodium nitroprusside (SNP; 1, 5, and 15 nmol) increased BP dose-dependently. Intrathecal pretreatment of methylene blue (200 nmol) significantly attenuated the pressor response evoked by SNP (15 nmol, i.t.). I.t. administration of nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester (100 and 1000 nmol), caused decreases in BP. These results suggest that NO plays a tonic excitatory role in the central regulation of BP in the rat spinal cord.

Animals↗

PubMed1996

Molecular cloning, splice variants, expression, and purification of phospholipase C-delta 4.

Complementary DNAs encoding a previously unidentified phosphoinositide-specific phospholipase C (PLC) isozyme were cloned from a rat brain cDNA library by the polymerase chain reaction with degenerate oligonucleotide primers based on sequences common to three known delta-type PLC isozymes. The encoded polypeptide contains 772 amino acids (calculated molecular mass, 88,966 daltons) and is similar in primary structure to delta-type PLC isozymes, with overall sequence identities of 45% to PLC-delta 1, 72% to PLC-delta 2, and 47% to PLC-delta 3. Thus, the new PLC isozyme was named PLC-delta 4. Recombinant PLC-delta 4 was purified from extracts of HeLa cells that had been infected with vaccinia virus containing the corresponding cDNA. The purified protein exhibited an apparent molecular mass of 90 kDa on SDS-polyacrylamide gels. The specific activity of PLC-delta 4 and its dependence on Ca2+ were similar to those of PLC-delta 1. The distribution of PLC-delta 4 in 16 different rat tissues was studied by immunoblot analysis with PLC-delta 4-specific antibodies of fractions obtained after an enzyme-enrichment procedure. The 90-kDa immunoreactive protein was detected unambiguously in only eight tissues and was present at concentrations that were low compared to those of other major PLC isozymes. A 93-kDa immunoreactive protein was also prominent in testis but was not detected in the other seven positive tissues. The 93-kDa enzyme appears to be derived from a splice variant of the mRNA that encodes the 90-kDa PLC-delta 4 and contains an additional 32 amino acids between the X and Y catalytic domains. Splice variants have not previously been detected for delta-type PLC isozymes.

Alternative Splicing↗

PubMed1996

Sleep-related periodic leg movements associated with spinal cord lesions.

We describe three patients who developed progressive paraparesis and sleep-related periodic leg movements (SRPLM) associated with thoracic spinal cord lesions; one patient had a schwannoma and two had intramedullary lesions. The patients showed periodic repetitive involuntary movements involving one or both lower limbs. The involuntary movements consisted of a single rapid dorsiflexion of the great toe or ankle, two to four repetitive dorsiflexions of the toes and ankle, and a mixture of repetitive jerks and prolonged spasms causing flexion of the hip and knee and dorsiflexion of the ankle and toes. In the patient with a schwannoma, paraparesis and SRPLM improved completely after surgical removal of the mass lesion. In one patient the SRPLM associated with an intramedullary lesion improved markedly after levodopa treatment. We suspect that thoracic spinal lesions partially disinhibit the lumbosacral generator. Such disinhibition seems to be enhanced by the activation of the neuronal systems related to periodic somatic and vegetative phenomena during sleep.

Adult↗

PubMed1996

A new linear solvation energy relationship for the solubility of liquids in water.

From a comparison between the linear solvation energy relationship (LSER) and the extended solubility parameter model, it has been found that the solute-solute interaction energy term is missing in the LSER equation. A new LSER equation with the supplementary interaction energy term has been proposed for the solvation process. It is shown that the new LSER equation yields the correct solute-solvent interaction terms for the solubilities of liquids in water.

Linear Models↗

PubMed1996

Occupational health and safety in the biotechnology industry--a survey of practicing professionals.

A survey was created to gauge how health and safety (H&S) resources are allocated in the biotechnology industry and to help understand the concerns of industry H&S professionals. A questionnaire was distributed to "the person most responsible for health and safety" at 34 companies; 12 commercial firms responded. Nearly 68% of the work force monitored did not fall into any biohazard classification. Almost 80% of work involving biohazards was considered "exempt" or "BL-1" under the Centers for Disease Control and Prevention classification system, indicating that most work was performed involving organisms of low pathogenic potential. H&S program development and administration is mature; 100% of respondents report having written programs for chemical, biological, and physical hazards. Chemical safety programs occupied, on average, the greatest percentage of the H&S professionals' time (46%), followed by biosafety (29.6%) and physical hazards (16.4%). The person most responsible for H&S averaged 65% of work time on H&S issues, while only 25% described their full-time responsibilities as H&S related. Staffing levels for companies with more than about 100 technical workers approximated 1.0-1.5 full-time H&S staff equivalents per 100 technical workers. This figure compares favorably with levels reported in a benchmarking survey of hospitals. Investigation into accident rates as a measure of H&S program effectiveness suggests that the biotechnology industry is a relatively safe one. Lost time injury and illness rates were significantly lower for the 12 participating companies than the accident frequency rates in the Standard Industrial Classification codes selected for comparison.

Accidents, Occupational↗

PubMed1996

Regulated expression of the interferon-induced protein kinase p68 (PKR) by vaccinia virus recombinants inhibits the replication of vesicular stomatitis virus but not that of poliovirus.

A direct antiviral role of the interferon-induced human protein kinase p68 has been shown only against encephalomyocarditis virus (EMCV) and vaccinia virus (VV). To determine if p68 kinase (PKR) has a broad antiviral effect, we have used coinfections between VV recombinants expressing p68 kinase under regulation of the lac I operator/repressor elements of Escherichia coli and two RNA viruses, vesicular stomatitis virus (VSV) and poliovirus. In cells coinfected with VV recombinants and VSV, induction with isopropyl-B-D-thiogalactoside (IPTG) of wild-type p68 kinase or a mutant lacking the dsRNA binding domain resulted in inhibition of both VV and VSV protein synthesis. This inhibition is not observed in cells infected with a catalytically inactive point mutant lys-arg296 of p68 kinase. When cells are coinfected with VV recombinants and poliovirus, induction of active p68 kinase resulted in a decrease in VV proteins but not in poliovirus proteins or poliovirus yields. Immunoblot analysis revealed that p68 kinase was expressed during mixed infections. Our results demonstrate a differential effect of p68 kinase on the replication of VV, VSV, and poliovirus. We suggest that in a particular virus-cell system, the different sensitivity of a virus to p68 kinase is probably due to levels of active enzyme.

Animals↗

PubMed1996

Autophosphorylation sites participate in the activation of the double-stranded-RNA-activated protein kinase PKR.

The interferon-induced RNA-dependent protein kinase PKR is found in cells in a latent state. In response to the binding of double-stranded RNA, the enzyme becomes activated and autophosphorylated on several serine and threonine residues. Consequently, it has been postulated that autophosphorylation is a prerequisite for activation of the kinase. We report the identification of PKR sites that are autophosphorylated in vitro concomitantly with activation and examine their roles in the activation of PKR. Mutation of one site, threonine 258, results in a kinase that is less efficient in autophosphorylation and in phosphorylating its substrate, the initiation factor eIF2, in vitro. The mutant kinase is also impaired in vivo, displaying reduced ability to inhibit protein synthesis in yeast and mammalian cells and to induce a slow-growth phenotype in Saccharomyces cerevisiae. Mutations at two neighboring sites, serine 242 and threonine 255, exacerbated the effect. Taken together with earlier results (S. B. Lee, S. R. Green, M. B. Mathews, and M. Esteban, Proc. Natl. Acad. Sci. USA 91:10551-10555, 1994), these data suggest that the central part of the PKR molecule, lying between its RNA-binding and catalytic domains, regulates kinase activity via autophosphorylation.

Amino Acid Sequence↗

PubMed1996

Spasmodic dysphonia associated with a left ventrolateral putaminal lesion.

A 34-year-old man presented with a 30-year history of spasmodic dysphonia. He developed a speech disturbance 1 month after a closed head injury due to a fall. Sighing, coughing, and crying were normal. He had a tremor of the right hand when he drew a vertical line. His out-stretched right hand had a minimal dystonic posture with occasional jerks of the fingers. T1-weighted axial brain MRI study showed a low signal intensity lesion at the putamen; coronal and axial T2-weighted MRI brain scans showed a high and low signal intensity lesion confined to the middle part of the ventrolateral putamen. Damage to the ventrolateral putamen may have caused abnormal voluntary control of the laryngeal muscles.

Adult↗

PubMed1996

Validation of multiplex polymorphic STR amplification sets developed for personal identification applications.

Polymorphic short tandem repeat (STR) loci, which typically consist of variations in the number of 3-7 base pair repeats present at a site, provide an effective means of personal identification. Typing can be accomplished by amplification of genomic DNA using the polymerase chain reaction (PCR) and locus-specific primers, separation of amplified alleles using gel electrophoresis and their display using silver staining or fluorescent detection. Primers for several STR loci can be combined in a single multiplex reaction so typing of multiple loci can be accomplished rapidly and with less DNA than required if each locus were analyzed separately. Before such muliplex systems are used in forensic or paternity applications, it is desirable that they undergo testing for their reliability. This study evaluates the performance of two STR triplex systems, one containing the loci HUMCSF1PO, HUMTPOX, and HUMTH01, and the other containing HUMHPRTB, HUMFESFPS, and HUMVWFA31. Protocols for amplification of these two triplexes, and their corresponding monoplexes, were evaluated for sensitivity of detection, resistance to changes in the annealing temperature of the amplification protocol, and the ability to identify the minority contributor in amplification of mixed samples. In addition, five laboratories determined the alleles of twenty DNA samples, each extracted by one of four different extraction methods. The results illustrate that the two STR triplex systems and the monoplex systems contained within them can be used with as little as 0.25 ng of DNA template. Both triplexes amplified with 100% success using the Perkin Elmer Model 480 thermal cycler. With the GeneAmp 9600 System, the CTT triplex amplified with 100% success and the HFv triplex in 95.6% of attempts. These experiments meet many requirements for use in validation of DNA typing systems for forensic cases and paternity identification.

Anthropology, Physical↗

PubMed1996

Unilateral fetal mesencephalic grafting in two patients with Parkinson's disease: short-term result after transplantation.

Fundamental pathological and neurochemical changes in Parkinson's disease are loss of midbrain dopamine neurons that innervate the caudate and putamen. In an effort to replenish the striatal dopaminergic innervation, fetal mesencephalic tissue containing dopamine cells was implanted into the unilateral putamen in two patients with severe Parkinson's disease. The tissue was obtained from three fetuses with gestational ages of 7 to 9 weeks. The cell suspension was stereotactically injected into the unilateral putamen using 5 needle trajectories. Postoperative immune suppression was not performed. Clinical improvement appeared after 2 months. Both patients showed improvement according to the Activities of Daily Living Scale during the off and practically-defined off state 9 and 14 months after surgery. The motor scores of the Unified Parkinson's Disease Rating Scale improved during the off and practically-defined off state 9 and 14 months after surgery. Dyskinesia and off state were shorter and less severe than before the transplantation. Although the long-term effects need to be ascertained, our short-term observation in these two patients with unilateral transplantation is encouraging and justifies further research trials in selected patients.

Activities of Daily Living↗

PubMed1995

Symptomatic ganglion cyst within the substance of the anterior cruciate ligament.

Many previous investigators have reported the findings of ganglion cysts on the surface of the anterior cruciate ligament. The cysts reported in the literature were either symptomatic or only of incidental findings. So far, however, there has not yet been a report of a ganglion cyst within the substance of the anterior cruciate ligament. This is the first report of a ganglion cyst within the substance of the anterior cruciate ligament, which caused intermittent swelling and pain in the right knee of a 13-year-old girl without any history of trauma. The cyst was treated successfully with an arthroscopic debridement and arthroscopically guided needle aspiration.

Adolescent↗

PubMed1995

Significance of PIP2 hydrolysis and regulation of phospholipase C isozymes.

Phosphatidylinositol 4,5-bisphosphate (PIP2) is an important component of several intracellular signaling pathways. It serves as a substrate for phospholipase C, which produces the second messengers inositol 1,4,5-trisphosphate and diacylglycerol. It is also a substrate for a phosphatidylinositol 3-kinase, and regulates the function of a number of actin-binding proteins. PIP2 has been shown recently to serve as a cofactor for a phosphatidylcholine-specific phospholipase D and as a membrane-attachment site for many signaling proteins containing pleckstrin homology domains. The need to stringently regulate the cellular concentration of PIP2 is reflected in part by the fact that there are at least ten distinct mammalian phospholipase C isozymes and multiple mechanisms linking these isozymes to various receptors.

Actins↗

PubMed1995

Evidence suggesting a role for phospholipase C isozyme, PLC-delta 1 in corticomedullary osmotic gradients in rat kidneys.

We determined the distributional patterns of phospholipase C isozymes within the rat kidneys. PLC-beta1 was localized in the inner medulla at the highest degree followed by the inner stripe of the outer medulla, the cortex and the outer stripe of the outer medulla. PLC-gamma1 was distributed homogeneously along the corticomedullary axis. PLC-delta1 showed gradual increase from the cortex to the inner medulla. Tissue osmotic gradients were measured using 4 slices, resulting in gradual increase from the cortex to the inner medulla. The pattern of PLC-delta1 appeared very similar to the osmotic gradient in the kidney. The results suggest that the distinct patterns of the PLC isozymes may be associated with different signal transduction pathways along the corticomedullary axis and PLC-delta1 may play a role in the osmoregulation of the medullary region.

Animals↗

PubMed1994

Activation of the double-stranded RNA (dsRNA)-activated human protein kinase in vivo in the absence of its dsRNA binding domain.

The interferon-induced, dsRNA-activated human protein kinase (PKR) exerts antiviral and antiproliferative effects through inhibition of protein synthesis. Studies of structure-function relationships in PKR have shown that two dsRNA binding motifs are important for its autophosphorylation and activation by dsRNA in vitro. To correlate these findings with the activity of PKR in vivo, we examined the function of various PKR deletion mutants in cultured cells by using an inducible expression system. In a reporter gene assay, mutant forms of the kinase lacking amino acids 1-97 (delta 1-97) and 104-157 (delta 104-157), which are required for dsRNA binding in vitro, retained full activity in vivo. Deletion of amino acids 233-271 (delta 233-271), however, abolished the translational inhibitory activity of the kinase and prevented its phosphorylation. Moreover, cells infected with vaccinia virus recombinants expressing wild-type PKR, the mutant delta 104-157, delta 186-222), developed almost complete inhibition of both viral and cellular protein synthesis was upon induction of PKR. This inhibition of viral protein synthesis was not observed in cells infected with a recombinant expressing delta 233-271 mutant PKR. Our findings establish that the region encompassing amino acids 233-271 of PKR is critical for kinase activity in vivo, whereas its dsRNA binding domain is dispensable.

Animals↗