A simple method for the removal of epithelium grown beneath the hinge after LASIK

The purpose of this study is to demonstrate a method of how to remove epithelium grown beneath the hinge area after laser in situ keratomileusis (LASIK) without affecting the refractive part of the lenticule. In three cases, an incision was made at the base of the hinge by RK diamond knife to free the lenticule from the stroma. The lenticule was lifted from the nasal edge. The epithelium grown along the interface beneath the hinge area was removed with a Bard-Parker No. 15 knife. The lenticular flap was repositioned with interrupted sutures using 10-0 nylon. No further epithelial ingrowth was observed. The central cornea remained clear leaving a peripheral ring-shaped opacity without affecting the preoperative naked visual acuity. In conclusion, epithelial ingrowth along the interface after LASIK can be removed safely without affecting the refractive part by the incision of the hinge area with a RK diamond knife, removal of the epithelium, and suturing of the lenticule to the stromal bed.

A peptide from hog plasma that inhibits human cholesteryl ester transfer protein

A peptide that inhibits the human cholesteryl ester transfer protein (CETP) was isolated from hog plasma by ultracentrifugation, two sequential column chromatographies and electroelution from gels. Molecular weight of the peptide was determined to be approximately 3 kDa on the SDS-PAGE. The peptide contained 28 amino acids with an identical sequence to the amino terminus of hog apolipoprotein-CIII except two amino acid residues: -Pro-Glu- at the fifth and sixth amino acids from the amino terminus in the isolated peptide, in contrast to -Leu-Leu- in hog apo-CIII. A peptide synthesized chemically according to the amino acid sequence of the peptide (designated P28) showed approximately the same degree of CETP inhibitory activity as the isolated peptide. Synthetic peptides with different number of amino acids were also tested for CETP inhibition. Among the peptides, the one with 20 amino acid residues (P20) from the amino terminus showed the highest inhibitory activity against the CETP. The peptide appeared to be associated with the hog high-density lipoproteins (HDL), as determined by immunoblot analysis using antibody against P28. The CETP-inhibitory activity of the peptide was examined in vivo using diet-induced hypercholesterolemic rabbits. When the peptide was injected into the rabbits (7-9 mg/kg body weight), approximately 75% CETP activity disappeared from the plasma in 1 h after the injection and the effect lasted up to 30 h. The inhibition of CETP in vivo led to a concomitant decrease in total plasma cholesterol level up to 30% and an increase in the level of HDL-cholesterol up to 32%. The cholesterol concentrations in the rabbit plasma gradually recovered to the initial level after 48 h.

Differential expression of ferritin heavy chain in THP-1 cells infected with Mycobacterium bovis BCG

To identify the host genes induced or suppressed by infection of mycobacteria, the reverse transcriptase polymerase chain reaction (RT-PCR) and the differential display reverse transcriptase polymerase chain reaction (DD RT-PCR) methods were used. In this study, cDNAs complement to mRNA extracted from human peripheral monocyte derived naive THP-1 cells, THP-1 cells infected with live Mycobacterium bovis BCG, THP-1 cells treated with heat-killed BCG, and THP-1 cells incubated with IgG-coated glass-beads were compared on the sequencing gel. One (TG2-1) of the clones selected by DD RT-PCR is 446 bp long and is identical to human ferritin heavy (H) chain gene. Northern blot analysis confirmed that ferritin H chain gene has been markedly over-expressed in monocytic THP-1 cells incubated with live and dead M. bovis BCG. Differential display techniques of host genes whose expression levels were varied by infection of mycobacteria could provide information about the response of macrophages to mycobacterial infection.

Cloning and sequencing of the secY gene homolog from Mycobacterium bovis BCG

The complete nucleotide sequence of a 1,513 bp fragment of Mycobacterium bovis BCG containing the secY gene homolog and partial adk gene that encodes an adenylate kinase has been determined. The secY gene of BCG has an open reading frame of 441 amino acids with homology to the SecY protein family. Comparative analyses of the deduced amino acid sequence of additional partial ORF revealed strong similarity to the known adenylate kinases.

Peptide-specific CTL induction in HBV-seropositive PBMC by stimulation with peptides in vitro: novel epitopes identified from chronic carriers

Cytotoxic T lymphocytes (CTL) recognize and destroy virus-infected cells, and it has been established that epitope-based peptides could induce such CTL in vivo as well as in vitro. In this study attempts were made to define the epitopes that are recognized by the CTL, and thus a series of 9- to 10-mer peptides derived from the amino acid sequences of hepatitis B virus (HBV) proteins were synthesized on the basis of the previously described HLA-A2 peptide binding motif. The binding assay of the synthetic peptides using transporter-associated with antigen processing (TAP)-deficient human cell line, T2, showed that eight out of 11 peptides tested enhanced the expression of HLA-A2 molecules on the T2 cell surface. Some of these peptides triggered activation of CTL in peripheral blood mononuclear cells of HBV-seropositive chronic carriers. The activated CTL in turn recognized and killed the T2 cells pulsed with the same peptides. This study shows that novel HLA-A2-restricted epitopes exist in the natural repertoire of immunity against HBV. These findings can be useful in developing peptide-based therapeutics against viral infections.

Complete sequence of the UPP gene encoding uracil phosphoribosyltransferase from Mycobacterium bovis BCG

The nucleotide sequence of a 799 bp fragment of Mycobacterium bovis BCG containing the putative upp gene that encodes a uracil phosphoribosyltransferase (UPRTase [EC 2.4.2.9]) has been determined. The upp gene of BCG has an open reading frame (ORF) of 621 bp (207 amino acids) starting with GTG (position 112) and ending with TGA (position 733), and its molecular mass was calculated to be 21,864 Da. Comparative analyses of the deduced amino acid sequence of BCG UPRTase with the UPRTase of six bacterial genera revealed that 24% (50/211) of the residues are perfectly conserved and 32% (67/211) of the residues are well conserved.

Consumer attitudes toward healthcare marketing practices: a comparison of hospitals vs. physicians

This study investigates consumer attitudes toward the use of marketing practices by the health care industry. The survey results show significant differences in consumers' attitude toward the use and effects of various marketing practices by the two types of provider (hospital and physician). Theoretical and empirical implications are discussed.

Cloning and characterization of cDNA for human adenylate kinase 2A

We have isolated and characterized a cDNA clone encoding human adenylate kinase 2A (AK2A) from cDNA libraries of fetal liver origin. The complete nucleotide sequence of the cloned 889 nucleotide cDNA fragment indicated that the deduced gene product of human AK2A is composed of 239 amino acids with a molecular weight of 26 kD. Comparison of these nucleotide and amino acid sequences with the corresponding sequences of bovine AK2A and rat AK2 revealed a high degree of conservation. It showed 91% and 98% homologies in DNA and amino acid sequences, respectively, with bovine AK2A throughout the full open reading frame. RNA blot analysis revealed that three species of mRNA were present with approximate sizes of 3.4, 2.1, and 1.0 kb. This gene was expressed in E. coli cells and the recombinant protein was enzymatically active.

A status report on helium inductively coupled plasma mass spectrometry

The current status of helium inductively coupled plasma - mass spectrometry (He ICPMS) is examined, its potentials and limitations are reviewed, and a summary of fundamental properties of atmospheric pressure He ICP discharges is presented. Also included are results of He ICPMS studies with a new helium plasma torch (18 mm i.d.) operated at four sets of operating conditions. Under the "cold plasma" condition (600 W forward power), no secondary discharge is observed and ion kinetic energies ranging from 2.0 eV to 9.5 eV for 6 elements (mass range: 39-208) are measured. At higher power levels, the secondary discharge still is strong. In general, detection limits for certain elements are improved by 1-3 orders of magnitude compared to previous data acquired in 1993 with a 13-mm He ICP torch. Elements such as K, Fe, Cr, Mn, Ni, and Co that suffer from spectral interferences in Ar ICPMS can be detected at pg/mL-levels with an analogue detector and a prototype ICPMS instrument having no photon stops or obstacles present in the ion trajectory path.

pH changes observed in the inflamed gingival crevice modulate human polymorphonuclear leukocyte activation in vitro

Previous studies have noted a positive correlation between gingival inflammation and crevicular pH, which reportedly varies from 6.5 to 8.5. In the present study, we characterized the manner in which deviation from the "physiological" pH of blood (7.2) influences activation of chemotaxis, phagocytosis, superoxide generation, and degranulation by human polymorphonuclear leukocytes (PMNs). Purified PMNs were suspended in HEPES-buffered balanced salts solutions adjusted to pH 6.7, 7.2, 7.7, or 8.2. In a modified Boyden chamber, the chemotactic response to fMet-Leu-Phe was maximal at pH 7.2. In comparison, chemotaxis was significantly depressed at pH 7.7 and pH 8.2 (P < 0.05), but was not significantly different at pH 6.7. Activation of the respiratory burst by fMet-Leu-Phe was optimal at pH 7.2, but was significantly depressed at pH 6.7 and 8.2 (P < 0.05). pH had little effect on N-acetyl-beta-glucosaminidase release from primary granules. However, lactoferrin release from the secondary granules of fMet-Leu-Phe-activated PMNs was significantly lower at pH 7.2 than at pH 6.7 or 8.2 (P < 0.05). Moreover, phagocytosis of opsonized bacteria was significantly lower at pH 7.2 than at pH 7.7. In addition to these effects on functional activation, extracellular pH influenced the magnitude of intracellular Ca2+ mobilization. Peak fMet-Leu-Phe-induced Ca2+ levels were significantly higher at pH 8.2 than at pH 7.2 (P < 0.01). These findings suggest that the pH of the periodontal environment can selectively influence PMN activation, thereby altering the balance between bacteria and the host response.

Selection of peptides that bind to the HLA-A2.1 molecule by molecular modelling

Cytotoxic T lymphocytes recognize antigenic peptides in association with major histocompatibility complex class I proteins. Although a large set of class I binding peptides has been described, it is not yet easy to search for potentially antigenic peptides without synthesis of a panel of peptides, and subsequent binding assays. In order to predict HLA-A2.1-restricted antigenic epitopes, a computer model of the HLA-A2.1 molecule was established using X-ray crystallography data. In this model nonameric peptide sequences were aligned. In a molecular dynamics (MD) simulation with two sets of peptides known to be presented by HLA-A2.1, it was important to know the anchor amino acid residue preference and the distance between the anchor residues. We show here that the peptides bound to the HLA-A2.1 model structure possess a side chain of C-terminal anchor residue oriented into the binding groove with different distances between the two anchor residues from 15 to 21A. We also synthesized a set of nonamer peptides containing amino acid sequences of Hepatitis B virus protein that were selected on the basis of previously described HLA-A2.1 specific motifs. When results obtained from the MD simulation were compared with functional binding assays using the TAP-deficient cell line T2, it was evident that the MD simulation method improves prediction of the HLA-A2.1 binding epitope sequence. These results suggest that this approach can provide a way to predict peptide epitopes and search for antigenic regions in sequences in a variety of antigens without screening a large number of synthetic peptides.

The effects of protection by D-Pen2-D-Pen5-enkephalin or D-Ala2-NMePhe4-Gly-ol-enkephalin against beta-chlornaltrexamine in the spinal cord on the antinociception induced by beta-endorphin administered intracerebroventricularly in the mouse

Chlornaltrexamine (beta-CNA, 0.5 micrograms) alone or beta-CNA plus either mu-agonist, D-Ala2-NMePhe4-Gly-ol-enkephalin (DAMGO, 500 ng) or delta-agonist, D-Pen2-D-Pen5-enkephalin (DPDPE, 10 micrograms) was injected intrathecally (i.t.) to protect mu- or delta-opioid receptors, respectively, for 24 h in male ICR mice. The antinociception was assessed by the tail-flick and hot-plate test. DPDPE or DAMGO injected i.t. increased inhibition of the tail-flick and hot-plate response in a dose-dependent manner. The dose-response curve for tail-flick and hot-plate response induced by DPDPE or DAMGO in i.t. saline-treated group significantly shifted to the right in i.t. beta-CNA alone treated group but returned to the control level in the group treated with i.t. beta-CNA coadministered with DPDPE or DAMGO, respectively. The effects of protection of mu- and delta-opioid receptor in the spinal cord on inhibition of the tail-flick and hot-plate response induced by beta-endorphin and morphine administered intracerebroventricularly (i.c.v.) were then studied. Intrathecal pretreatment with beta-CNA or beta-CNA coadministered with DAMGO attenuated inhibition of the tail-flick response induced by beta-endorphin administered i.c.v. However, i.t. treatment with beta-CNA coadministered with DPDPE did not affect inhibition of the tail-flick response induced by beta-endorphin administered i.c.v. Intrathecal pretreatment with beta-CNA or beta-CNA coadministered with either DPDPE or DAMGO did not alter inhibition of the hot-plate response induced by beta-endorphin administered i.c.v.(ABSTRACT TRUNCATED AT 250 WORDS)

Tamoxifen suppresses tumor promoter-induced hydrogen peroxide formation by human neutrophils

Trans-tamoxifen (TAM) has been used successfully in therapy for estrogen-dependent human breast tumors and prevention of their recurrence. The mechanism of this prevention was thought to be due to the interference of TAM with estrogen promotion. TAM has a wider anticarcinogenic action that is similar to other chemopreventive agents in that it suppresses tumor promotion in 2-stage carcinogenesis by interfering with the action of protein kinase C. We report that TAM (5 microM) totally inhibits hydrogen peroxide (H2O2) formation by 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-treated human neutrophils. Interestingly, beta-estradiol (10 microM) also slightly inhibits the oxidative burst of neutrophils. Pretreatment of neutrophils with varying amounts of TAM and beta-estradiol caused additive inhibition of H2O2 formation by the 2 agents. 4-Hydroxy-tamoxifen, a metabolite with the highest affinity for the estrogen receptor, was only as inhibitory as beta-estradiol. Other derivatives (cis-, N-desmethyl-, and N-desdimethyl-tamoxifen) with low biological activities had a smaller effect on H2O2 formation. TPA-treated neutrophils were shown to contain 5-hydroxymethyl uracil (HMU). TAM prevented the TPA-induced formation of HMU in other cells. Like TPA, dietary fat, which is a risk factor for breast cancer, induces formation of HMU in the DNA of human white blood cells. TAM may suppress the dietary fat-induced HMU in the same manner at it does in TPA-induced neutrophils.

Expression of increased immunogenicity by thiol-releasing tumor variants

Even moderate variations of the extracellular cysteine concentration were previously shown to affect T cell functions in vitro despite high concentrations of cystine. We therefore analyzed the membrane transport activities of T cells for cysteine and cystine, and the role of low molecular weight thiol in T cell-mediated host responses against a T cell tumor in vivo. A series of T cell clones and tumors including the highly malignant lymphoma L5178Y ESb and its strongly immunogenic variant ESb-D was found to express extremely weak transport activity for cystine but strong transport activity for cysteine. However, not all cells showed the expected requirement for cysteine (or 2-mercaptoethanol (2-ME)) in the culture medium. One group of clones and tumors including the malignant ESb-lymphoma did not respond to changes of extracellular cystine concentrations and was strongly thiol dependent. This group released only little acid soluble thiol (cysteine) if grown in cystine-containing cultures. The other T cell lines, in contrast, were able to maintain high intracellular GSH levels and DNA synthesis activity in cystine-containing culture medium without cystein or 2-ME and released substantial amounts of thiol. This group included the immunogenic ESb-D line. Additional thiol-releasing ESb variants were obtained by culturing large numbers of L5178Y ESb tumor cells in cultures without cysteine or 2-ME. All of these ESb variants showed a significantly decreased tumorigenicity and some of them induced cytotoxic and protective host responses even against the malignant ESb parent tumor. Taken together, our experiments suggest that the host response against a tumor may be limited in certain cases by the failure of the stimulator (i.e., the tumor) cell to deliver sufficient amounts of cysteine to the responding T cells.

Suprasellar and intraventricular blood predict elevated plasma atrial natriuretic factor in subarachnoid hemorrhage

Following subarachnoid hemorrhage, the plasma concentration of atrial natriuretic factor is elevated and appears to be independent of atrial stretch. While the hypothalamus and circumventricular organs contribute to sodium and intravascular volume regulation, their influence on atrial natriuretic factor is not known. We tested the hypothesis that, following subarachnoid hemorrhage, suprasellar cisternal blood, intraventricular blood, or ventricular enlargement would be associated with elevated plasma levels of atrial natriuretic factor. Computed tomograms of 26 patients performed less than or equal to 3 days after hemorrhage were analyzed to determine the presence of suprasellar or intraventricular blood and enlargement of the third or lateral ventricle. These results were correlated with the plasma atrial natriuretic factor and serum sodium concentrations. The initial atrial natriuretic factor concentration was elevated and was higher in patients with suprasellar or intraventricular blood than in those without (suprasellar: 131 +/- 20 and 54 +/- 10 pg/ml, respectively; intraventricular: 137 +/- 25 and 84 +/- 31 pg/ml, respectively). The atrial natriuretic factor concentration remained higher over the week following hemorrhage in patients with suprasellar blood than in those without (127 +/- 16 and 68 +/- 12 pg/ml, respectively). The atrial natriuretic factor concentration was not correlated with hyponatremia (125-134 meq/l) or age-corrected ventricular size. Hyponatremia did not correlate with the presence of intraventricular or suprasellar blood. Our data suggest that suprasellar and intraventricular blood disturb hypothalamic function, resulting in an elevated plasma atrial natriuretic factor concentration. The presence of a direct relation between atrial natriuretic factor and hyponatremia remains unclear.

Automatic shadow moiré topography: a moving-light-source method

A method for automatically determining in real time the absolute order of shadow moiré fringes is developed. The intensity variations on an object surface caused by a light source moving with constant speed are analyzed by fast-Fourier-transform methods. Experimental results show that this procedure can be successfully applied to shadow moiré topography and does not require object surface continuity.

Additive type moire with computer image processing

Due to its poor visibility additive type moire is seldom used in spite of its simplicity. By means of computer image processing, the visibility of additive moire can be improved in real time to that of subtractive type moire. Experimental results for moire topography show that the additive type moire is no longer an inadequate method.

Determinant attributes in formulation of attitudes toward four health care systems

Consumers were surveyed to determine their attitudes toward four systems of health care delivery (home health care, hospitals, nursing homes, and outpatient clinics) along 10 attributes. The results are analyzed using multiple discriminant analysis. Implications for the formulation of marketing strategies are discussed.

Sandhoff disease heterozygote detection: a component of population screening for Tay-Sachs disease carriers. II. Sandhoff disease gene frequencies in American Jewish and non-Jewish populations

Carrier frequencies for the allele(s) causing Sandhoff disease have been estimated for the U.S. Jewish and non-Jewish populations. The estimates have been made directly, with data from 22,043 Jewish and 32,342 non-Jewish individuals measured for total serum hexosaminidase activity and the heat-labile fraction. These values have been shown to identify potential carriers of the Sandhoff allele(s) with 95% sensitivity. Subsequent leukocyte assays of total hexosaminidase activity and the heat-labile fraction in those identified in serum tests have been shown to provide a much finer discrimination between those who carry the allele(s) and those who do not. Results from such assays were used to generate these carrier frequency estimates. Carrier frequency estimates have also been made indirectly from Sandhoff disease incidence data collected during the period 1979-84. These estimates are in agreement with data for the Jewish population under analysis, but in the non-Jewish population the estimate derived from data on screened individuals is greater than the estimate derived from incidence figures. The possible causes for such a difference are discussed. In a study of non-Jewish individuals each of whose grandparents derives from a single country of origin, the distribution of countries among Sandhoff disease carriers differs significantly from that in the non-Jewish sample under analysis, indicating possible ethnic groups with increased or decreased carrier frequencies. These analyses suggest an increased Sandhoff disease carrier frequency among Mexican and Central-American populations and a decreased carrier frequency among non-Jewish German populations.

Sandhoff disease heterozygote detection: a component of population screening for Tay-Sachs disease carriers. I. Statistical methods

Serum and leukocyte hexosaminidase profiles (total activity and percent heat-labile activity levels) in obligate Sandhoff disease (SHD) heterozygotes differ from those of obligate Tay-Sachs disease (TSD) heterozygotes and noncarrier individuals. We have developed a procedure to identify, with 95% sensitivity, carriers of the allele(s) for SHD among individuals screened in a TSD heterozygote identification program. Using multivariate statistical methods of cluster analysis and discriminant analysis on serum and leukocyte hexosaminidase profiles from 102 potential SHD carriers, a linear discriminant function to classify individuals as SHD carriers or SHD noncarriers was constructed. This function classifies the serum and leukocyte profiles from all 15 obligate SHD heterozygotes studied, as those of SHD carriers. A 95% isodensity ellipse derived from only the serum hexosaminidase profiles of the 15 SHD obligate carriers has been applied to a TSD screened sample of 37,843 Jewish and non-Jewish individuals. A potential recall rate of screened individuals for serum retests and leukocyte assays of 2.01% has been estimated. These statistical methods enhance the TSD heterozygote screening program by permitting one to detect SHD heterozygotes within the screened population.

Intensity perception. XIII. Perceptual anchor model of context-coding

In our preliminary theory of intensity resolution [e.g., see N. I. Durlach and L. D. Braida, J. Acoust. Soc. Am. 46, 372-383 (1969)], two modes of memory operation are postulated: the trace mode and the context-coding mode. In this paper, we present a revised model of the context-coding mode which describes explicitly a process by which sensations are coded relative to the context and which predicts a resolution edge effect [L. D. Braida and N. I. Durlach, J. Acoust. Soc. Am. 51, 483-502 (1972); J. E. Berliner, L. D. Braida, and N. I. Durlach, J. Acoust. Soc. Am. 61, 1256-1267 (1977)]. The sensation arising from a given stimulus presentation is coded by determining its distance from internal references or perceptual anchors. The noise in this process, combined with the sensation noise, constitutes the limitation on resolution in the model. In the revised model the probability density functions of the decision variable are not precisely Gaussian (and cannot be expressed analytically in closed form). This paper outlines the predictions of the model for one-interval paradigms and for fixed-level two-interval paradigms and derives estimates of the values of model parameters.