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Biomedical subjects

H Lee

Publications and source records attributed to H Lee.

At least 757 records · Page 42Linked to original sources
PubMed1989

Human immunodeficiency virus and human T-cell leukemia virus type I in patients undergoing maintenance hemodialysis in Miami.

The high prevalence of human immunodeficiency virus (HIV-1) infection in populations at risk in Miami prompted a seroepidemiologic study of both HIV-1 and the human T-cell leukemia virus type I (HTLV-I), a closely related virus, in our patients receiving chronic hemodialysis. One hundred twenty-nine patients undergoing hemodialysis in 1986 and 1987 were tested for antibody against both viral antigens by EIA (Abbott Laboratories, Abbott Park, IL). Seroreactive samples for HIV-1 and/or HTLV-I were confirmed by Western blot and, for HTLV-I, by viral cultures. Thirty patients (23.2%) were positive for retroviral infection (22 for HIV-1 alone, four for HTLV-I alone, and four for both HIV-1 and HTLV-I). The most important risk factor was intravenous drug use, followed by blood transfusion. Patients with HIV-1 had lower T4-T8 ratios and higher mortality than those with HTLV-I infection alone. It was concluded that HTLV-I, as well as HIV-1, infection is endemic in chronic dialysis centers in Miami. The clinical consequences of HTLV-I infection in relatively immunocompromised patients with chronic uremia who are undergoing chronic hemodialysis remains to be established.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Epidemiologic background of blood donors with antibody to human T-cell lymphotropic virus. Transfusion Safety Study Group.

We interviewed 51 blood donors in four major US metropolitan areas subsequently found to have had antibodies to human T-cell lymphotropic virus (anti-HTLV) in late 1984-early 1985. Sixteen donors (31%) reported that they or a sexual contact had a history of blood transfusion. Twelve donors (24%) reported that they or a sexual contact used intravenous drugs. Ten donors (20%) were blacks born in the southeastern US. Four of the male donors (15%) reported homosexual contact. The most common characteristic was an association with Japan or the Caribbean basin (61%). These results show a broader variation of epidemiologic backgrounds than anticipated.

Adult↗
PubMed1989

Genital chlamydial infection in female and male college students.

A review of more than 1,000 medical records of the University of South Florida students screened for gonorrhea, Chlamydia trachomatis, and syphilis during a period of 1 year in 1986-1987 showed genital chlamydial infection to be the most prevalent of these sexually transmitted diseases (STDs). Among normal asymptomatic female students with no known recent STD contact, 6.9% had a positive chlamydial enzyme immunoassay. Female students with vaginal symptoms had a greater tendency to be positive, and 47.8% of those with a recent STD contact tested positive for chlamydia. Males with a clinical diagnosis of nonspecific urethritis had a 50% probability of having a positive chlamydia test. Data from this study clearly support a need for a screening policy and educational program on the campus to improve control of chlamydial infection.

Adult↗
PubMed1989

Physiological Properties of a Mutant of Pachysolen tannophilus Deficient in NADPH-Dependent d-Xylose Reductase.

A d-xylose reductase mutant of Pachysolen tannophilus was isolated on the basis of its poor growth on d-xylose but normal growth on xylitol and d-glucose. Fractionation of cell extracts indicated that the mutant was deficient in d-xylose reductase activity that used NADPH exclusively as a cofactor, but not in activity that used both NADH and NADPH. Mutant cultures grown on d-xylose as the sole carbon source exhibited some properties that would be desired in improved strains. Growth rate, growth yield, and d-xylose consumption rate of the mutant were less sensitive than those of the wild type to changes in aeration rate. d-Xylose was utilized more efficiently in that less of a by-product, xylitol, was produced. In addition, under low aeration conditions, more ethanol was produced. A disadvantage was a relatively slow rate of d-xylose utilization.

Journal Article↗
PubMed1989

Role of the kidney in metabolic change of interleukin-2.

The metabolic change of human recombinant interleukin-2 (IL-2) was investigated by the use of 125I-labeled IL-2 (125I-IL-2). After intravenous injection into mice, the distribution of 125I-IL-2 in various organs revealed that the major portion of injected 125I-IL-2 was rapidly accumulated in the kidney. Simultaneous injection of an excess amount of cold IL-2 greatly reduced the distribution of 125I-IL-2 to the kidney, suggesting that the accumulation of 125I-IL-2 by the kidney was a specific reactivity between 125I-IL-2 and the kidney. The gel filtration profile of 125I-IL-2 in the serum specimens remained the same as that of the originally injected sample, and differed completely from that in the urine specimens, suggesting that 125I-IL-2 was metabolized in the kidney. To confirm this notion, 125I-IL-2 was incubated in vitro with kidney homogenate, which degraded 125I-IL-2 in acidic pH. After subcellular fractionation, the cytosol fraction of the kidney was shown to hydrolyze 125I-IL-2 with an optimal pH of 4. The reactivity of the kidney cytosol fraction with 125I-IL-2 was inhibitable by pepstatin, an acid protease inhibitor, but not by TLCK or TPCK. Additional experiments using a heat-treated kidney cytosol fraction plus cathepsin D, and pepstatin inhibition on the degradation of 125I-IL-2 by cathepsin D, a major acid protease in the kidney, resulted in the identification of this enzyme to be responsible for the degradation of 125I-IL-2. Overall, these results demonstrated that the kidney is the organ to metabolize IL-2 and that cathepsin D, a renal acid protease, is involved in the degradation of IL-2.

Animals↗
PubMed1989

Controlled trial of external negative pressure ventilation in patients with severe chronic airflow obstruction.

The effect of intermittent external negative pressure ventilation (ENPV) with the Emerson Pulmowrap ventilator upon leg cycle endurance time (ET), maximal transdiaphragmatic pressure (Pdimax), breathing pattern as expressed by the tension time index (TTdi), and sense of well being was studied in 16 patients with severe chronic airflow obstruction (CAO). The patients were randomized to 3 wk of in-hospital pulmonary rehabilitation (Group I, seven patients) or the same program plus ENPV (Group II, nine patients). Both groups were similar in terms of age (65 +/- 8 versus 61 +/- 13 yr), severity of CAO (FEV1 of 0.64 +/- 0.14 versus 0.59 +/- 0.18 L), and PaCO2 (44 +/- 9 versus 45 +/- 7 mm Hg). Blood theophylline levels and nutritional status were also similar in both groups. Baseline ET (2.9 +/- 0.6 versus 3.8 +/- 1.6 min) and Pdimax (45 +/- 15 versus 56 +/- 18 cm H2O) were decreased in both groups. Baseline TTdi was high but similar in both groups; at rest the values were 0.15 +/- 0.05 versus 0.16 +/- 0.04, and at end-exercise they were 0.17 +/- 0.06 versus 0.21 +/- 0.12. After treatment FEV1 and Pdimax remained unchanged, but the patients in both groups manifested clinical improvement and had a significant increase in mean ET (Group I from 2.9 to 6.9 and Group II from 3.8 to 6 min, p less than 0.01). TTdi decreased both at rest (0.14 +/- 0.07 versus 0.13 +/- 0.04) and at end-exercise (0.14 +/- 0.06 versus 0.15 +/- 0.09) with no difference between groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Obstruction↗
PubMed1989

Growth determinants in the core-periphery of Korea.

"This article describes the emergent spatial dispersion pattern of the urban system of the Republic of Korea, where the government has instituted a strong decentralization policy. Intraregional decentralization is underway within the core area, while intraregional polarization towards larger regional centers is evident in periphery areas. Through the use of step-wise regression analysis, determinants of the differential growth rates of urban centers in the core and periphery are identified. The different spatial development processes operating in the core and periphery have implications for growth pole theory and regional development planning."

Asia↗
PubMed1989

Detection of human T-cell leukemia/lymphoma virus type I in a transfusion recipient with chronic myelopathy.

A white man with a progressive spastic paraparesis that began 15 months after sustaining severe trauma in a motor vehicle accident was positive for antibodies to human T-lymphotropic virus type I (HTLV-I) by enzyme-linked immunosorbent assay. Serum antibody to HTLV-I was confirmed by Western blot and radioimmunoprecipitation assay. We detected specific proviral DNA in peripheral blood lymphocytes by the polymerase chain reaction. Because the incidence of HTLV-I is generally restricted to Southern Japan and Caribbean black populations, the most likely source of HTLV-I infection in this patient was multiple intraoperative blood transfusions. The relatively short interval between transfusion and development of HTLV-I-associated myelopathy is consistent with the more rapid evolution of this clinical syndrome compared with adult T-cell leukemia.

Chronic Disease↗
PubMed1988

Immunoelectron microscopic localization of actin in neurites of cultured embryonic chick dorsal root ganglia: actin is a component of granular, microtubule-associated crossbridges.

Axons have been shown to contain substantial quantities of actin distributed along their length. However, the general lack of information on the structure and organizational state of this protein in axons has made it difficult to assign it a functional role. In the present study, we used electron microscopic immunocytochemistry (immunogold labeling) on neurites from cultured embryonic chick dorsal root ganglia to: (1) determine the distribution of actin in neurites: (2) identify actin-containing structures; and (3) reveal whether or not actin is associated preferentially with microtubules. Results show that actin is present throughout neurites but is organized primarily into short filaments that are localized almost exclusively to granular, microtubule-associated crossbridges. We propose that these short actin filaments are part of the framework of a supramolecular 'carrier complex' for the slow component b polypeptides. In addition, actin-containing crossbridges are often closely associated with the surfaces of membrane-bound organelles. This suggests that actin and microtubule-associated crossbridges are involved somehow in fast axonal transport, although the nature of their participation in this process still needs to be resolved.

Actins↗
PubMed1988

Immunohistochemical comparison of Lea, monosialosyl Lea (CA 19-9), and disialosyl Lea antigens in human colorectal and pancreatic tissues.

The CA 19-9 antigen is a monosialosyl Lea blood group antigen which has been shown to be a useful tumor-associated antigen for the diagnosis of gastrointestinal cancers. Recently, a sialylated derivative of this antigen, disialosyl Lea, was isolated from a colon cancer liver metastasis and a monoclonal antibody (FH7) recognizing this novel determinant was developed. The present study simultaneously compared the expression of Lea, monosialosyl Lea, and disialosyl Lea antigens in a variety of nonmalignant, premalignant, and malignant tissues of the colorectum and pancreas with an aim toward elucidating whether disialosyl Lea is expressed as a tumor-associated antigen. In normal colonic mucosa, disialosyl Lea expression closely resembled Lea expression in overall frequency, segmental distribution, and cellular localization whereas monosialosyl Lea (CA 19-9) was essentially absent. Along the crypt axis, Lea was more often expressed in goblet cells of the upper crypt whereas disialosyl Lea was found in goblet cells along the entire crypt. Fetal colonic mucosa expressed all three antigens, as did most colorectal cancers regardless of location within the colon or degree of differentiation. The majority of hyperplastic polyps and practically all adenomatous polyps also expressed these three antigens, and in adenomas, antigen expression was independent of polyp size, villous morphology, or degree of dysplasia. In the normal pancreas, the three antigens were expressed on ductal, ductular and centroacinar cells of all specimens. The majority of pancreatic cancers expressed all three antigens. Thus, in the normal colon, the absence of monosialosyl Lea (CA 19-9) in the presence of disialosyl Lea suggests that an alpha 2,6 sialyltransferase is active, which results in the masking of CA 19-9 antigen expression. These results further support the concept that specific sialyltransferases play a role in regulating the expression of tumor-associated antigens.

Antibodies, Monoclonal↗
PubMed1988

Structure of [Mg(HO3PCH(C6H5)2)2].8H2O, a layered phosphonate salt.

Bis(hydrogen diphenylmethylphosphonato)-magnesium octahydrate, [Mg(C13H12O3P)2].8H2O. Mr = 662.85, triclinic, P1, a = 6.1051 (15), b = 8.8308(14), c = 15.312(3) A, alpha = 78.514(13), beta = 83.993(11), gamma = 75.772(15) degrees, V = 782.8(3) A3, Z = 1, Dx = 1.41 g cm-3 (163 K), Mo K alpha, lambda = 0.71069 A, mu = 2.171 cm-1, F(000) = 350, T = 163 K, R = 0.0351 for 3749 reflections [F0 greater than or equal to 4 sigma(F0)]. The structure consists of alternating polar and nonpolar layers stacked along the crystallographic c axis. The polar layers contain Mg(H2O)26+ ions, water of hydration and the phosphonate O atoms, and the nonpolar layers contain the benzhydryl groups. Two-dimensional hydrogen-bonding networks link Mg(H2O)26+ and the water of hydration to the phosphonate O atoms. The shortest hydrogen bonds in the structure, 1.68(2) A, connect the P-OH H atom and the water of hydration. Slightly longer contacts [1.79(2), 1.85(2), 1.91(2), 1.92(2) A] connect the phosphonate O atoms (O1 and O3) to the H atoms of the Mg(H2O)26+ group. The coordination environment of the Mg atom is a very nearly regular octahedron of water O atoms.

Chemical Phenomena↗
PubMed1988

Conformational states of N-acylalanine dithio esters: correlation of resonance Raman spectra with structures.

The conformational states of N-acylalanine dithio esters, involving rotational isomers about the RC(=O)NH--CH(CH3) and NHCH(CH3)--C(=S) bonds, are defined and compared to those of N-acylglycine dithio esters. The structure of N-(p-nitrobenzoyl)-DL-alanine ethyl dithio ester has been determined by X-ray crystallographic analysis; it is a B-type conformer with the amide N atom cis to the thiol sulfur. Raman and resonance Raman (RR) measurements on this compound and for the B conformers of solid N-benzoyl-DL-alanine ethyl dithio ester and N-(beta-phenylpropionyl)-DL-alanine ethyl dithio ester and its NHCH(CD3)C(=S) and NHCH(CH3)13C(=S) analogues are used to set up a library of RR data for alanine-based dithio esters in a B-conformer state. (Methyloxycarbonyl)-L-phenylalanyl-L-alanine ethyl dithio ester crystallizes in an A-like conformational state wherein the alanine N atom is nearly cis to the thiono S atom (C=S) [Varughese, K.I., Angus, R.H., Carey, P.R., Lee, H., & Storer, A.C. (1986) Can. J. Chem. 64, 1668-1673]. RR data for this solid material in its isotopically unsubstituted and CH(C-D3)C(=S) and CH(CH3)13C(=S) forms provide information on the RR signatures of alanine dithio esters in A-like conformations. RR spectra are compared for the solid compounds, for N-(p-nitrobenzoyl)-DL-alanine, N-(beta-phenylpropionyl)-DL-alanine, and (methyloxycarbonyl)-L-phenylalanyl-DL-alanine ethyl dithio esters, and for several 13C=S- and CD3-substituted analogues in CCl4 or aqueous solutions. The RR data demonstrate that the alanine-based dithio esters take up A, B, and C5 conformations in solution.(ABSTRACT TRUNCATED AT 250 WORDS)

Acylation↗
PubMed1988

Conformational variability in an enzyme's active site: resonance Raman evidence for different acyl group conformations in N-acylglycine and N-acylalanine dithioacyl papains.

It is demonstrated that the vibrational modes associated with the catalytically labile region of N-acylalanine dithioacyl papains undergo a major reorganization compared to the normal modes of corresponding model compounds. Thus, the resonance Raman (RR) spectrum of, e.g., N-benzoylalanine dithioacyl papain and its response to isotopic labeling cannot be understood completely on the basis of the RR spectrum of N-benzoylalanine ethyl dithio ester in one of its known conformational states [detailed in Lee, H., Angus, R. H., Storer, A. C., Varughese, K. I., & Carey, P. R. (1988) Biochemistry (preceding paper in this issue)]. This situation contrasts sharply to that for N-acylglycine dithioacyl papains whose RR spectra closely resemble those of the corresponding N-acylglycine ethyl dithio esters in a conformational state known as conformer B. For the N-acylalanine intermediates two possible causes are put forward to explain the rearrangement of the normal modes. First, the acyl groups based on alanine may bind in papain's active site in a conformation whose torsional angles near the -C(=S)S-group differ markedly from those of characterized model compounds. The second, and presently favored, explanation is that the N-acylalanine moiety is binding in the active site in an A- or C5-like conformation and that, in addition, there is significant vibrational coupling between some of the normal modes of the bound substrate and the normal modes associated with parts of the enzyme in contact with the substrate. The finding that deacylation for N-acylglycine or N-acylalanine dithioacyl papains must proceed from structures which are different is an indication that the mechanism of deacylation may not have strict stereochemical requirements.(ABSTRACT TRUNCATED AT 250 WORDS)

Acylation↗