Quantum-well and tight-binding analyses of spin-polarized photoemission from Ag/Fe(001) overlayers.
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Journal Article↗
Biomedical subjects
Y Chang
Publications and source records attributed to Y Chang.
Cytokines in the central nervous system: expression of macrophage colony stimulating factor and its receptor during development.
To investigate the potential role of cytokines in the development of the central nervous system, we analyzed the production of cytokine mRNA transcripts by S1-nuclease protection analysis in the brains of Swiss-Webster mice during fetal development and after birth. Cytokines studied were interleukin (IL)-1 alpha, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, macrophage-colony stimulating factor (M-CSF), granulocyte-colony stimulating factor (G-CSF), granulocyte macrophage-colony stimulating factor (GM-CSF), and leukemia inhibitory factor (LIF). Only mRNA transcripts for M-CSF were found to be produced constitutively in normal brain tissue. These transcripts were detected continuously from embryonic day (ED) 13 through adulthood. Transcripts encoding the M-CSF receptor (c-fms) were also detected at all of these time points. Despite identification of M-CSF transcripts in the brains of normal mice during development and M-CSF protein in cell cultures, neuropathological examination of the brains of op/op mice, a naturally occurring mouse mutant defective in the production of functional M-CSF, showed no cytoarchitectural abnormalities.
Age Factors↗
HYP1, a hydrophobin gene from Aspergillus fumigatus, complements the rodletless phenotype in Aspergillus nidulans.
Aspergillus fumigatus produces conidia that are highly dispersable and resistant to degradation. We have sought to analyze these properties by studying the rodlets which form the outer spore coat protein. Degenerate primers based on hydrophobins in other fungi were applied to genomic DNA from A. fumigatus in PCR. A product of this reaction with similarity to an Aspergillus nidulans gene as judged by Southern hybridization was chosen for further study. Cloning and sequencing revealed a gene with two introns which encodes a protein of 159 amino acids. Structural characteristics consistent with those of other fungal hydrophobin genes, especially conserved cysteine residues, are present. The expression of the gene is limited to the developmental stages in which maturing conidiophores are present. This A. fumigatus gene, HYP1, was used to transform a mutant strain of A. nidulans that lacks rodlets. Transformants with a single copy of HYP1 expressed a rodlet layer on their conidia as observed by freeze-fracture electron microscopy.
Amino Acid Sequence↗
Overusage of mouse DH gene segment, DFL16.1, is strain-dependent and determined by cis-acting elements.
The DJH structure is of particular importance for diversity in the immunoglobulin heavy chain because it encodes most of CDR3. Here, we investigate mechanisms responsible for generating the DJH structure. We found DFL16.1 was used at a high frequency in normal and transformed pre-B cells (fetal liver > 50%, A-MuLV lines approximately equal to 25%). One DFL16.1JH1 structure was found repeatedly and was also present in DJH and VDJH databases, suggesting this structure may be conserved in the primary repertoire. Genetic analysis demonstrated that C57BL/6 mice use DFL16.1 in DJH structures more frequently than BALB/c. Examination of individual alleles in (C57BL/6 x BALB/c)F1 A-MuLV cell lines revealed that the C57BL/6-derived allele used DFL16.1 twice as often as the BALB/c. This result indicates that part of the mechanism ensuring overusage of DFL16.1 gene segments is cis-acting.
Alleles↗
Induction of the autoantigen proliferating cell nuclear antigen in T lymphocytes by a mycobacterial antigen.
Mycobacteria have been implicated in the pathogenesis of autoimmunity. To determine the potential effect of mycobacterial antigens on peripheral blood mononuclear cells (PBMC), we analyzed PBMC incubated with the acetone-precipitable fraction of Mycobacterium tuberculosis (APMT) for changes in cellular protein expression. Two-dimensional gel analysis showed induction of a 36-kD polypeptide identified as proliferating cell nuclear antigen (PCNA), a known autoantigen, after incubation with AP-MT. PCNA plays a role in cell proliferation and is expressed as a late growth regulated factor. However, its synthesis in response to AP-MT was induced as an early event. The early induction of PCNA was regulated at a posttranscriptional level and was restricted to T cells. Treatment of PBMC with known T cell mitogens, namely PHA, anti-CD3 antibodies, and staphylococcal superantigens failed to induce an early PCNA increase. The distinct characteristics of the AP-MT effect on PCNA expression suggest a separate mechanism of induction in response to AP-MT, compared with the late increase observed in response to mitogens. The induction of PCNA in response to mycobacterial antigens may represent a pathogenically relevant mechanism in autoimmunity.
Antigens, Bacterial↗
Early results of the advanced coronary endarterectomy combined with CABG in the treatment of coronary artery occlusive disease.
BACKGROUND: Coronary Endarterectomy is a controversial but effective procedure for diffuse coronary artherosclerosis. Between April 1991 and January 1993, 57 patients in VGH-Taipei who had their diffuse coronary artery disease treated with combined endarterectomy and coronary artery bypass grafting (CABG). METHODS: One hundred and thirty-eight endarterectomies were performed, including 6 on the left main coronary artery system, 77 on the left anterior descending coronary artery system, 15 on left circumflex coronary artery system and 40 on the right coronary artery system (an average of 2.42 endarterectomies/patient). For graft conduit, great saphenous vein was used in 149 anastomoses, left internal mammary artery in 21, right internal mammary artery in 6 and right gastroepiploic artery in 4. The mean number of distal graft anastomoses was 3.15 per patient. Additional procedures were performed in 8 patients (14%): two patients required aortic valve replacement, one patient had mitral valve replacement, one had mitral annuloplasty, one had VSD repair and three had left ventricle aneurysm plications. The mean aortic clamp time was 108.8 +/- 30.5 minutes. RESULTS: The early mortality rate was 5.3%. The late mortality rate was 3.5%. During follow-up of mean 17.5 months, 98% of survivors were asymptomatic or in improved condition. CONCLUSIONS: Although endarterectomy is still a debatable procedure, it is valuable especially for the diffusely diseased arteries.
Aged↗
Precipitation profile of the intravenous induction agents.
To investigate the formation of precipitation between various intravenous agents, we cross-matched the anesthetic agents commonly used in the induction phase. Thiopentone and thiamylal precipitated in combination with non-depolarizing muscle relaxants, lidocaine, morphine, and meperidine. Ketamine and etomidate were naive to these agents. Crystalloidal solutions, such as lactated Ringer, normal saline, and dextrose solution did not contribute to the formation of precipitate. In conclusion, our study indicates that intravenous line must be irrigated before and after thiopentone and/or thiamylal. In order to prevent precipitate formation, mixtures of various drugs should be avoided until in vitro assay is done.
Anesthesia, Intravenous↗
Propofol modifies recovery from isoflurane-nitrous oxide anesthesia.
A randomized, prospective study was performed to evaluate the hemodynamic changes and recovery characteristics in 60 ASA physical status class I-II unpremedicated patients undergoing gynecological laparotomies with either isoflurane anesthesia only (ISO group) or isoflurane anesthesia followed by propofol infusion (ISO-PRO group). All patients received isoflurane 0.5-1.5% and nitrous oxide (N2O) 66% in oxygen after tracheal intubation. ISO-PRO group (n = 30) received 6 mg kg-1 hr-1 propofol infusion in substitution for isoflurane 25 minutes before the end of surgery. Propofol in ISO-PRO group and isoflurane in ISO group (n = 30) were discontinued 5 minutes before the end of surgery. In both groups, N2O was administered throughout the operation until skin was closed. Hemodynamic measurements were similar between the two groups except at extubation when heart rate and blood pressure were lower in ISO-PRO group. The maximal blood pressure was also lower in ISO-PRO group. In ISO-PRO group, the time required to responsiveness to verbal commands and to orientation were significantly shorter. ISO-PRO group had better Steward's score on arrival at the recovery room and was earlier to get a full score of six. The two groups experienced similar rates of emesis and excitement either two hours or 24 hours postoperatively. We conclude that in relatively long intra-abdominal operations, replacement of isoflurane by propofol infusion 25 minutes before the end of surgery may provide stable maintenance of anesthesia and a faster recovery.
Adult↗
Synchronous carotid endarterectomy and myocardial revascularization.
BACKGROUND: The management of the coexisting extracranial carotid and coronary disease is still controversial. We reviewed our experience in synchronous operation for both diseases in Veterans General Hospital-Taipei. METHODS: From Jan. 1988 to Nov. 1992, the synchronous carotid endarterectomy and myocardial revascularization were performed in nine patients with the mean age of 66.6 +/- 11 years. Five had symptomatic extracranial vascular disease or stabilized neurological deficits, and four had asymptomatic carotid bruits. Four had bilateral hemodynamically significant carotid stenosis. NYHA functional class III-IV was noted in three patients. Triple-vessel coronary disease was documented in 6 patients including one with left main lesion more than 50%. Eight had previous or recent myocardial infarction and four had moderate to severe left ventricular dysfunction noted on left ventriculography. RESULTS: All nine patients received unilateral carotid endarterectomy and a mean number of 2.8 distal anastomosis. Operative number of 2.8 distal anastomosis. Operative mortality within 30 days was zero and morbidity was noted in two patients. One patient was CVA and the other one was perioperative myocardial infarction. Late mortality occurred in previous two patients with morbidity. Late morbidity was mainly due to cardiac rather than neurological problems. CONCLUSIONS: If long-term natural history of coronary or carotid artery disease could be actually altered by surgery, a systemic evaluation for possible multifocal atherosclerosis is mandatory. By following a proposed guideline, synchronous operation is appropriate for a subgroup of patients with coexisting carotid and coronary artery disease.
Aged↗
Nutritional status of preschool children in poor rural areas of China.
Described are the main findings of the first large-scale nutrition monitoring project carried out over a 4-year period in China. The nutritional status of nearly 10,000 preschool children in 18 comparatively poor rural areas in seven provinces was followed each year over the period 1986-89 in order to identify their major nutritional problems and improve their growth and development. Physical measurements were made and dietary surveys and biochemical tests were performed on a subsample of the children. The proportion of stunted and underweight children was far higher than the national average. Based on the possibilities offered by local circumstances, the prevalences of stunting and underweight were lowered and anaemia was greatly reduced. Along with the progress in nutrition monitoring, major efforts were made to train health workers, as well as to encourage increased production of green vegetables, poultry, and small livestock. The wealth of information collected and the experience gained may serve as a baseline record, the project currently being expanded to cover 100 counties throughout China.
Anemia↗
Spin polarization of quantum well states in copper thin films deposited on a Co(001) substrate.
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Journal Article↗
High frequency of normal DJH joints in B cell progenitors in severe combined immunodeficiency mice.
The severe combined immunodeficiency (scid) mouse has a defective V(D)J recombinase activity that results in arrested lymphoid development at the pro-B cell stage in the B lineage. The defect is not absolute and scid mice do attempt gene rearrangement. Indeed, approximately 15% of all scid mice develop detectable levels of oligoclonal serum immunoglobulin and T cell activity. To gain more insight into the scid defect and its effect on V(D)J rearrangement, we analyzed DJH recombination in scid bone marrow. We determined that DJH structures are present in scid bone marrow and occur at a frequency only 10-100 times less than C.B-17+/+. The scid DJH repertoire is limited and resembles fetal liver DJH junctions, with few N insertions and predominant usage of reading frame 1. Moreover, 70% of the DJH structures were potentially productive, indicating that normal V(D)J recombinants should be arising continually.
Animals↗
Inherited syndrome of infantile olivopontocerebellar atrophy, micronodular cirrhosis, and renal tubular microcysts: review of the literature and a report of an additional case.
An 8-month-old male infant who presented in the neonatal period with failure to thrive, bilateral pleural and pericardial effusions, and hepatic insufficiency characterized by elevated liver functions tests and hypoalbuminemia was found at autopsy to have an unusual combination of olivopontocerebellar atrophy (OPCA), micronodular cirrhosis, and renal tubular microcysts. Metabolic evaluation was significant only for elevated urine dicarboxylic acids. In the brain, sections from the cerebellum showed marked atrophy of folia most severe in the vermal and paravermal regions. In addition, mild neuronal loss was present in the basis pontis and inferior olivary nuclei accompanied by gliosis. Residual Purkinje cells in the cerebellar hemispheres exhibited greatly expanded and swollen arbors, which ultrastructurally were found to contain densely packed membranous cytoplasmic body-like inclusions that had the appearance of unwinding, lamellar coils. Review of the literature shows that this constellation of findings has been associated with carbohydrate-deficient transferrin. This biochemical marker along with the distinctive clinical presentation and pathological features clearly delineates a unique subset of OPCA.
Cerebellum↗
In-vitro antimicrobial studies with the combination of cefoperazone and sulbactam.
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Ampicillin↗
Red-green flicker photometry and nonlinearities in the flicker electroretinogram.
We investigated whether responses from different cone classes are combined before or after the nonlinearity that is responsible for generating nonlinear response components of the flicker electroretinogram (ERG). We measured the nonlinear response of the retina while systematically varying the modulation in the long-wavelength-sensitive and middle-wavelength-sensitive cones by changing the proportions of flickering 633- and 543-nm lights that compose a sum-of-sinusoids temporal waveform. We found that at high temporal frequencies the ERG responses are best accounted for by a model in which the principal retinal nonlinearity is located before the convergence of signals from the two cone classes. At low temporal frequencies the ERG signal is dominated by cone-antagonistic responses. At frequencies of 30 Hz and higher, the flicker ERG and psychophysical flicker photometry give similar estimates of the relative proportions of long- and middle-wavelength-sensitive cones. The ERG photometric null is frequency dependent, whereas the psychophysically determined ratio is much less sensitive to changes in frequency.
Color Perception↗
Prevention of heterosexual transmission of human immunodeficiency virus through couple counseling.
In the absence of an effective vaccine, behavior change remains the most effective means to prevent the spread of HIV. We examined behavior change over time and rates of HIV seroconversion in a cohort of HIV individuals and their heterosexual partners recruited since 1985. Participants were recruited from various HIV counseling and testing sources throughout California and were usually interviewed and tested in their own homes. Couple counseling and risk assessments were conducted at average intervals of six months. Data from 144 couples who were discordant for HIV serostatus are reported. Of the index cases, 78% were men. Most male index cases were bisexuals, and most female index cases were infected through heterosexual intercourse with a previous sexual partner. The mean duration of the relationship for the couple at intake was 5.6 years. Both condom use and sexual abstinence increased over time (p < 0.001 for both), and most behavior change occurred between intake and first follow-up visit. We observed no seroconversion after 193 couple-years of follow-up. Couple counseling in combination with social support appears to be an effective means to promote and sustain behavior change among HIV-infected individuals and their heterosexual partners.
Adolescent↗
Right gastroepiploic artery: an alternative arterial conduit for coronary artery bypass.
From September 1990 to February 1991, 15 cases of myocardial revascularization with the right gastroepiploic artery (RGEA) combined with arterial or venous grafts were performed at VGH-Taipei. All were males, ranging in age from 49 to 64 years (mean age 61.2 +/- 4.6 years). The mean number of distal anastmoses including vein grafts was 3.6 +/- 0.7 and the mean number of graft was 3.1 +/- 0.3 per patient. The mean aortic clamp time was 123.6 +/- 24.0 minutes and the mean cardiopulmonary bypass time was 176 +/- 35 minutes. There was one mortality (6.7%). The other 14 patients are alive without angina. Studied within 3 postoperative months, graft early patency was 100% (6/6) in GEA graft. GEA graft should be a third available arterial conduit for coronary artery bypass.
Aged↗
Localized hypertrophic mononeuropathy of the trigeminal nerve.
We report a case of localized hypertrophic mononeuropathy that involved the trigeminal nerve in a 61-year-old woman with a 5-year history of progressive drooping of the left eyelid, double vision, and left-sided temporal and retro-orbital pain. A mass that occupied the patient's left cavernous sinus was found to display localized hypertrophic mononeuropathy characterized by "onion bulbs" that were formed of concentrically proliferating Schwann cell processes around intact axons. This contrasted to the majority of previously reported cases of localized hypertrophic mononeuropathy, predominantly found in peripheral nerves, where the proliferating cell processes have been shown to be of a perineurial cell origin. Differences in architectural arrangement and degree of cellularity between the perineurial and schwannian forms of localized hypertrophic mononeuropathy were noted. These findings suggest important fundamental differences in the pathogenesis of various forms of onion-bulb mononeuropathies.
Cranial Nerve Diseases↗