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Biomedical subjects

N Lee

Publications and source records attributed to N Lee.

At least 235 records · Page 13Linked to original sources
PubMed1991

Interactions of Neisseria gonorrhoeae with human neutrophils: studies with purified PII (Opa) outer membrane proteins and synthetic Opa peptides.

We investigated the role of gonococcal outer membrane protein PII (also called Opa protein) in nonopsonic adherence to human neutrophils. Gonococcal outer membranes, purified Opa in detergent (Opa), purified Opa in liposomes (Opa+ lips), and peptides composing the second hypervariable (HV2) region of OpaB (strain FA1090) in liposomes (pepHV2 lips) were tested for their abilities to inhibit subsequent gonococcal adherence to human neutrophils. Outer membranes from gonococci possessing adherent Opa, liposomes containing adherent Opa, purified adherent Opa, and two of three liposome preparations (pepHV2 lips) containing peptides from the HV2 region of an adherent Opa inhibited subsequent adherence to neutrophils of homologous Opa+ gonococci. On the other hand, outer membranes from Opa- gonococci, outer membranes containing a nonadherent Opa (OpaA from strain FA1090), purified OpaA, and OpaA lips had little or no inhibitory effect. Outer membranes containing adherent Opas, purified adherent Opas, and liposomes containing such Opas all bound to neutrophils, whereas preparations containing OpaA or no Opa protein did not. The results indicate that (i) Opa proteins can bind to neutrophils in a partially purified or purified form and (ii) the HV2 region of Opa appears to at least partially mediate Opa's biological role.

Amino Acid Sequence↗
PubMed1990

Granulocytic differentiation of HL-60 cells is associated with increase of poly-N-acetyllactosamine in Asn-linked oligosaccharides attached to human lysosomal membrane glycoproteins.

HL-60 cells were induced to differentiate into granulocytic cells by dimethyl sulfoxide, and structures of Asn-linked oligosaccharides attached to lysosomal membrane glycoproteins (lamp-1 and lamp-2) were elucidated before and after differentiation. Lamp-1 and lamp-2 were immunoprecipitated from the cells after labeling with radioactive sugars, and glycopeptides were prepared. The structures of glycopeptides obtained after serial lectin-affinity chromatography were elucidated by endo-beta-galactoside and methylation analysis. Glycopeptides bound to tomato lectin-Sepharose were found to be tetraantennary oligosaccharides that contain two or three poly-N-acetyllactosaminyl chains, of which one side chain contains three or more N-acetyllactosaminyl repeats, whereas those bound to Datura stramonium agglutinin-Sepharose were found to be tetraantennary oligosaccharides containing one or two short poly-N-acetyllactosaminyl side chains. Glycopeptides that were not bound to concanavalin A, tomato lectin, or D. stramonium agglutinin were found to be triantennary oligosaccharides with a negligible amount of poly-N-acetyllactosaminyl side chains. Comparison of Asn-linked oligosaccharides from undifferentiated and differentiated HL-60 cells reveals the following features. First, the number of Asn-linked oligosaccharides containing poly-N-acetyllactosaminyl side chains increases dramatically with a concomitant decrease in less complex Asn-linked oligosaccharides after differentiation. Second, the number of poly-N-acetyllactosaminyl side chains per Asn-linked oligosaccharides increases significantly. These increases in poly-N-acetyllactosamine were associated with increased activity of UDP-GlcNAc:beta-D-Gal-beta 1----3-N-acetylglucosaminyltransferase "extension enzyme," a key enzyme in the formation of poly-N-acetyllactosamines. Furthermore, the increased amount of poly-N-acetyllactosamine in lamp-1 and lamp-2 resulted in longer half-lives of lamp-1 and lamp-2 in differentiated HL-60 cells. These results suggest strongly that the differentiation of HL-60 cells into more phagocytic cells is associated with an increase in the complexity of Asn-linked oligosaccharides attached to lysosomal membrane glycoproteins, which in turn may play a role in stabilizing lysosomes.

Antigens, CD↗
PubMed1990

Clinical courses and treatment of splenic artery aneurysms--report of 3 cases and review of literatures in Japan.

We have treated three cases of splenic artery aneurysms recently, so we reported them with a review of 181 cases in Japan. All three cases are women and have characteristic clinical courses and pathogenesis in each to which we performed a reasonable operation so that they could be saved. First one is a ruptured case. So we performed ligation of the splenic artery from inside the aneurysm under 9 min.'s clamp of the aorta. Second one was pointed out the splenic artery aneurysm during admission for cholecystectomy, so we performed splenectomy and aneurysmectomy, and after that we reconstructed the splenic artery with end-to-end anastomosis. Third one suffered from splenomegaly and portal hypertension. We performed splenectomy with the aneurysm. From the clinical and pathological findings, we concluded that an aneurysm in our first case was associated with arterial dysplasia, second with hemodynamic changes in parous women, and third with portal hypertension. Aneurysms of the splenic artery have been rarely reported until recently, when developments in diagnostic procedures made their discovery easier. We have diagnosed splenic artery aneurysm in three patients preoperatively. The clinical symptoms and operative procedure was different in each case, and are reported here. We demonstrated the summary of our three cases of that at Table 1.

Aneurysm↗
PubMed1990

Comparison of four different methods for detection of Helicobacter pylori from gastric biopsies.

Helicobacter pylori are commonly found colonizing the gastric mucosa of different populations. Its presence may be important in the pathogenesis of gastritis and peptic ulcer disease. The detection rates vary widely depending upon the diagnostic methods applied. In this study, multiple gastric biopsies were taken from the fundal and antral mucosa of 25 patients during endoscopy. In one patient, the procedure was repeated about two months after the initial biopsy. A total of 52 sets of specimens were obtained. One sample from each site was used to make imprint smear and tissue section. The other sample was used for microbiological culture and rapid urease test. An association between histological confirmed chronic gastritis (both active and inactive) and the morphological diagnosis of H. pylori by tissue sections was found in all of the 26 cases (52 specimens). There was an excellent concordance (96.2%) between the morphological diagnosis of H. pylori in the Gram-stained imprint smears and the tissue sections. There was a good concordance (86.5%) between the histology and the bacterial culture. Interestingly, a different species of gastric campylobacter-like organism with similar morphological appearance was also cultivated. The results of rapid urease test are unsatisfactory because urease was detected in less than 10% of culture-positive biopsies after 1 hour and 71.1% after 24 hours. In summary, culture and histology are complementary to each other. The combination of both is the "gold standard" for confirming the presence of H. pylori. As for rapid diagnosis, the Gram-stained imprint smears are shown to give satisfactory results.

Adult↗
PubMed1990

Home self-administration of intravenous immunoglobulin therapy in children.

Twelve children with primary immunodeficiency, aged 2 to 17 years (mean +/- 1 SD = 9.8 +/- 5.3), were enrolled in a 9-month study to evaluate the feasibility and safety of home self-infusion of intravenous immunoglobulin (IVIg). An initial 2-month training and supervisory period was followed by a 6- to 7-month period during which the children or their parents infused IVIg in a home setting. Eight children received an average dose of 204 +/- 12 mg/kg every 2 weeks, two children received a dose of 400 mg/kg every month, and an additional two children received 240 to 250 mg/kg every 10 days. Peak and trough levels varied from 946 +/- 20 mg/dL and 627 +/- 16 mg/dL, respectively, in children receiving IVIg every 2 weeks. The peak-trough values for the children receiving IVIg every month were 1105 +/- 94 mg/dL and 457 +/- 78 mg/dL, while those of children receiving IVIg every 10 days were 840 +/- 24 mg/dL and 553 +/- 109 mg/dL. A total of 224 infusions were administered, with only two minor reactions occurring (reaction rate of 0.9%). There was no difference in the frequency of infections and antibiotic use during the study compared with the previous phase. The results demonstrate that home self-infusion of IVIg in children is safe and feasible.

Adolescent↗
PubMed1990

Detection of picogram amounts of nucleic acid by dot blot hybridization.

An increasing number of human proteins isolated from cell sources are being produced for pharmaceutical use. Consequently, federal agencies have required the quantitative determination of residual nucleic acids that copurify with the potential protein products. We have conducted these assays in connection with our application for licensure of Alferon Injection. We report a sensitive dot blot hybridization assay that was used to quantitate picogram (or less) amounts of nucleic acids which copurified with human proteins isolated from recombinant (S. cerevisiae) or natural (leukocytes) sources.

DNA↗
PubMed1989

[Cytomegalovirus infection in neonate--report of two cases].

The cytomegalovirus (CMV) is an abiquitous agent that infects almost all human beings at some time during their lives. In developing area of the world, 90% or more of the population is infected during childhood. However, in developed countries the infection is acquired at a lower rate. In neonates, CMV infection can be divided into congenital and perinatal infection. Congenital CMV infection is the result of transplacental transmission, CMV can be transmitted to the fetus following reactivation as well as primary infection during pregnancy. The incidence of congenital infection is 0.2% to 2.2%. Symptomatic congenital CMV infection is more likely to be the result of primary as opposed to reactive CMV infection during pregnancy. The clinical manifestations of symptomatic CMV infection are hepatosplenomegaly, microcephaly, jaundice, petechiae, small for gestation age, periventricular calcification and chorioretinitis. Mortality may be as high as 30% among the most severely affected infants. In the survivors, about 90% will develop mild to severe handicaps. Perinatal CMV infection can be acquired from exposure to virus in the maternal genital tract at delivery, breast milk, or through blood transfusion. In premature infants who require prolonged and intensive medical care, blood transfusions are an important iatrogenic cause of CMV infection. Transfusion-acquired perinatal CMV infection can cause significant morbidity and mortality, particularly in premature infants with a birth weight of less than 1250 gm born to CMV-seronegative mothers. So CMV acquisition can be prevented either by providing these infants blood products from seronegative donors or by using frozen deglycerolized red blood cells. Two cases of neonatal CMV infection are reported, one with congenital infection, the other with perinatal infection.

Cytomegalovirus Infections↗
PubMed1989

Lipid cell tumor of the ovary associated with endometrial adenocarcinoma--a case report.

Presented here is a case of a 54-year-old woman with a lipid cell tumor of the ovary associated with endometrial adenocarcinoma. Lipid cell tumor of the ovary is a rare tumor. From the previous literature, there are only four cases reported to be associated with endometrial adenocarcinoma. The history and the pathological findings will be presented along with the review of the literature.

Adenocarcinoma↗
PubMed1989

Glutathione regulates interleukin-2 activity on cytotoxic T-cells.

In this study, we examined whether and how the cellular activity of interleukin-2 (IL-2) is affected by glutathione (GSH), an important tripeptide existing in most cells. Cell culture and thymidine incorporation assay showed that addition of GSH enhanced the effect of IL-2 on the proliferation and thymidine incorporation of IL-2-dependent cytotoxic T-cells such as CTLL-2 and CT-4R. Treatment of the cells with GSH resulted in a 2-fold increase in the amount of IL-2 bound to the cells and a rapid internalization of the bound IL-2. In addition, the degradation of IL-2 in the cells was enhanced by GSH treatment. These effects of GSH were accompanied by an increase in the intracellular GSH level. L-Buthionine-(S,R)-sulfoximine, an inhibitor of de novo GSH synthesis, blunted the increase of intracellular GSH level and modulated the effect of GSH on IL-2 activity. These results suggest that GSH regulates the binding, internalization, degradation, and T-cell proliferative activity of IL-2; alterations of cellular GSH concentration may thus affect the growth and replication of IL-2-sensitive cytotoxic T-cells.

Animals↗
PubMed1989

The POEMS syndrome among Chinese: association with Castleman's disease and some immunological abnormalities.

POEMS or Crow-Fukase syndrome is a multisystemic, clinically malignant disorder of obscure etiology. Peripheral neuropathy and plasma cell dyscrasia are central features. The authors now report 7 Chinese patients with this syndrome in which PCD or paraproteinemia were absent in 6, and 2 had a lymph node histology resembling that of hyaline-vascular Castleman's disease. Immunological abnormalities consisted of either increased or decreased numbers of B- and T-cells in 2 cases, and an elevated OKT4/OKT8 ratio with paradoxical dissociation of the lymphocyte transformations to various concentrations and types of mitogens in 1 case. This suggests that the underlying abnormalities of POEMS syndrome are heterogeneous and that it may be an immunologically related syndrome of varying etiology.

Adult↗
PubMed1989

Hypesthetic ataxic hemiparesis in a thalamic lacune.

Right hemiparesis with an ipsilateral hypesthesia and ataxia developed in a 57-year-old man. Magnetic resonance imaging showed a left thalamic lacune bordering the medial portion of the posterior limb of the internal capsule. This finding implicated some pathogenetic mechanism of ataxic hemiparesis.

Ataxia↗
PubMed1989

[The ratios and kinds of clinical bacteria isolated in Taiwan's large-size hospitals].

The prevalence of clinical bacteria, as isolated from Linko Chang-Gung Memorial Hospital (2,300 beds) in the period January 1985 to December 1986 and from Taipei Veterans General Hospital (2,300 beds) during the period January 1986 to December 1986, was analyzed with the following findings: (i) The isolation ratio of anaerobic and aerobic or facultative bactria during the period of investigation were 7.8% (5,513/70,799) and 92.2% (65,286/70,799), respectively. (ii) Of the total aerobic or facultative isolates from the two hospitals, 32.9% (21,510/65,286) were Gram positive cocci and bacilli, 67.1% (43,776/65,286) were Gram negative cocci and bacilli. (iii) Of these Gram-negative bacilli, 65.2% (28,490/43,675) were Enterobacteriaceae were Enterobacteriaceae and glucose fermentative Gram negative bacilli, 32.0% (13,984/43,675) were glucose nonfermentative Gram negative bacilli, and 2.7% (1,200/43,675) were fastidious Gram negative bacilli. (iv) The more common species among the members of Enterobacteriaceae were Escherichia coli 35.7% (10,163/28,490), and Klebsiella pneumoniae 18.2% (5,186/28,490). The other common species included Enterobacter cloacae, Proteus mirabilis, Serratia marcescens, Morganella morganii, Citrobacter freundii and Proteus vulgaris. The frequencies of Salmonella species and Shigella species in these two large hospitals were up to 1.6% (456/28,490) and 0.5% (149/28,490), respectively. The most common isolate among other glucose fermentative Gram negative bacilli was Aeromonas hydrophila 3.0% (843/28,490). The finding of 0.1% (11/28,490) Vibrio alginolyticus was considered as clinically significant in Taiwan. (v) Of these glucose nonfermentative Gram negative bacilli, 69.4% (9,704/13,984) were Pseudomonas aeruginosa, 18.9% (2,637/13,984) Acinetobacter species, 10.8% (1,516/13,984) Pseudomonas species. (vi) The most common bacteria among fastidious Gram negative bacilli was Haemophilus influenzae, 96.2% (1,154/1,200). (vii) Of these Gram negative cocci, 59.4% (60/101) was Neisseria gonorrhoeae and 6.9% (7/101) N. meningitidis. (viii) The more common isolates of Gram positive bacilli included Bacillus species and Corynebacterium species (diphtheroids). (ix) Of these Gram positive cocci, the isolation rates of Staphylococcus species and Streptococcus species were 54.6% (10,838/19,827) and 45.4% (9,002/19,847), respectively. The most common isolate among Gram positive cocci was Staphylococcus aureus, 30.2% (5,994/19,847); the next, enterococcus, 24.9% (4,936/19,847); then S. epidermidis, 22.2% (4,390/19,847). The less common isolates were Streptococcus pyogenes 1.1% (212/19,847) and S. pneumoniae, 1.7% (329/19,847).(ABSTRACT TRUNCATED AT 400 WORDS)

Bacteria↗
PubMed1988

A simplified high speed multicolor immunoblotting method.

We describe a simplified technique for the rapid and specific detection of antigenic determinants within a mixed population of antigens. Each determinant develops its own characteristic color in a single Western blot or dot blot. This multicolor immunostaining technique can be achieved with as little as a one-step incubation, involving a mixture of different primary and developing antibodies, and a one-step substrate reaction, involving a mixture of different substrates. The time required can be reduced to short periods of time, ranging from minutes to about 1 h. This can represent an increase in the speed of detection by one to two orders of magnitude when compared with conventional methods. The simplified protocols may facilitate the automation of routine analyses.

Antibodies↗
PubMed1988

Biological characterization of human interleukin-2 mutant proteins. Structure-activity relationship studies.

Several human interleukin-2 (IL-2) mutant proteins have been produced previously by site-directed mutagenesis and found to have different capacities to induce T-cell proliferative activity. In this study, the abilities of these IL-2 mutant proteins to activate natural killer cells and to induce interferon-gamma production have been evaluated, and the binding of these proteins to IL-2 receptors analyzed. Natural killer cell activation and interferon-gamma induction assays showed that the relative activities of IL-2 mutant proteins were consistent with their relative activities in T-cell proliferation assay. Receptor-binding studies showed that the activities of most proteins correlated well with their respective affinities for high-affinity IL-2 receptors on CTLL-2 cells. Interestingly, although the mutant protein with deletion of cysteine 125 (des-Cys125) was biologically less active than the protein with substitution of alanine for cysteine 105 (Ala105), both proteins exhibited similar affinity. Des-Cys125, like IL-2 and Ala105, also caused down-regulation of high-affinity IL-2 receptors. Binding studies on MLA-144, a cell line expressing mainly intermediate-affinity IL-2 receptors (IL-2R beta), however, showed that des-Cys125 had much lower affinity than Ala105. These results suggest that binding of IL-2 and mutant proteins to the IL-2R beta component of the high-affinity receptor is essential for the induction of biological effects.

Animals↗
PubMed1988

AraC proteins with altered DNA sequence specificity which activate a mutant promoter in Escherichia coli.

We examined the recognition of the araBAD promoter by the AraC protein in the Escherichia coli arabinose operon. A mutant promoter, with base substitutions at positions contacted by AraC, was used to isolate suppressor mutations in araC by direct selection. Two hydroxylamine-induced araC mutations were isolated repeatedly; each contained a single amino acid substitution. When tested against a set of base substitution promoter mutants, one revertant, an Arg to His substitution at residue 250, displayed altered base specificity for a single position within the araBAD promoter. The other revertant, a Cys to Tyr substitution at residue 204, did not show consistent base-specific suppression. Neither demonstrated a higher affinity than the wild type protein for the mutant promoter in vitro. Both proteins suppress mutant sequences by a mechanism that does not appear to involve the formation of new net favorable contacts with the mutant base pairs of the promoter.

Alleles↗