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Biomedical subjects

Y Lee

Publications and source records attributed to Y Lee.

At least 487 records · Page 27Linked to original sources
PubMed1986

The presence of vasoactive intestinal polypeptide-like immunoreactive structures projecting from the myenteric ganglion of the stomach to the celiac ganglion revealed by a double-labelling technique.

The gastrofugal vasoactive intestinal polypeptide (VIP)-like immunoreactive (VIPI) structures in the rat were examined by the combined use of immunocytochemistry and retrograde tracing. Injection of biotin-wheat germ agglutinin into the celiac ganglion labeled many neurons in the myenteric ganglion of the stomach. Simultaneous staining with antiserum against VIP showed that some of these neurons are VIPI-positive. These findings indicate that VIPI neurons in the myenteric ganglion of the rat stomach project to the celiac ganglion.

Animals↗
PubMed1986

Screening of anti-HTLV antibody in sera of normal individuals and patients with malignancies in Taiwan.

In the present study an immunofluorescence using KH-2 cells as target cells, has been developed for the screening of 1200 serum samples from normal individuals and 450 of cases from patients with various malignancies. The positive anti-HTLV-I antibody rate in the former group is 0.083% (1/1200) and while in the latter it is found to be 1.8% (8/450) (including 3 adult T-cell leukemia/lymphoma cases of the 92 hematopoietic and 5 of 358 non-hematopoietic malignancies). The differences between the two groups are found to be significantly different (p value is less than 0.0001). In addition to the 3 adult T-cell leukemia/lymphoma cases, the 5 seropositive cancer patients are of 5 different diseases. We have searched for the adult T-cell leukemia virus antigen and the p19 core protein in lymphoid cells of seropositive persons and the only positive cases were from cells of two proven adult T-cell leukemia (ATL) patients. Our results suggest that Taiwan is not an endemic area of adult T-cell leukemia virus and that KH-2 cells may be used for the detection of anti-HTLV-I antibodies.

Adolescent↗
PubMed1986

Penicillin-binding site on the Escherichia coli cell envelope.

The binding of 35S-labeled penicillin to distinct penicillin-binding proteins (PBPs) of the "cell envelope" obtained from the sonication of Escherichia coli was studied at different pHs ranging from 4 to 11. At low pH, PBPs 1b, 1c, 2, and 3 demonstrated the greatest amount of binding. At high pH, these PBPs bound the least amount of penicillin. PBPs 1a and 5/6 exhibited the greatest amount of binding at pH 10 and the least amount at pH 4. With the exception of PBP 5/6, the effect of pH on the binding of penicillin was direct. Experiments distinguishing the effect of pH on penicillin binding by PBP 5/6 from its effect on beta-lactamase activity indicated that although substantial binding occurred at the lowest pH, the amount of binding increased with pH, reaching a maximum at pH 10. Based on earlier studies, it is proposed that the binding at high pH involves the formation of a covalent bond between the C-7 of penicillin and free epsilon amino groups of the PBPs. At pHs ranging from 4 to 8, position 1 of penicillin, occupied by sulfur, is considered to be the site that establishes a covalent bond with the sulfhydryl groups of PBP 5. The use of specific blockers of free epsilon amino groups or sulfhydryl groups indicated that wherever the presence of each had little or no effect on the binding of penicillin by PBP 5, the presence of both completely prevented binding. The specific blocker of the hydroxyl group of serine did not affect the binding of penicillin. These observations suggest that a molecule of penicillin forms simultaneous bonds between its S at position 1 and sulfhydryl groups of PBP 5 and between its C-7 and free epsilon amino groups of PBP 5.

Bacterial Proteins↗
PubMed1986

Soft tissue sarcomas and military service in Vietnam: a case comparison group analysis of hospital patients.

The possibility that exposure to Agent Orange or phenoxy herbicides may have increased the risk of soft tissue sarcomas has been of genuine concern to Vietnam veterans and their families. A hospital-based case comparison group study was undertaken to examine, through a comprehensive review of medical records and military personnel records, the association between previous military service in Vietnam and soft tissue sarcomas. The case group comprised 234 Vietnam-era veteran patients who served in the US military between 1964 and 1975 and were treated in one of the 172 VA hospitals between 1969 and 1983 with a diagnosis of soft tissue sarcomas. The comparison group consisted of 13,496 patients who were systematically sampled from the same Vietnam-era veteran patient population from which the cases were drawn. Military service information, in particular Vietnam service status, for each case and control patient was obtained from a review of the patient's military personnel records archived at the National Personnel Records Center in St Louis, Missouri. No significant association of soft tissue sarcomas and previous military service in Vietnam was observed: odds ratio was 0.83 with a 95% confidence interval of 0.63 to 1.09.

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed1985

Monoclonal antibodies as probes for determining the microheterogeneity of the link proteins of cartilage proteoglycan.

Monoclonal antibodies were raised against Swarm rat chondrosarcoma link protein 2. Two of the resultant hybridomas (9/30/6-A-1 and 9/30/8-A-4) were used in structural analyses of the link proteins. The 9/30/6-A-1 monoclonal antibody recognized an epitope which was only present on rat chondrosarcoma link protein 2. This epitope was absent in rat chondrosarcoma link protein 3 obtained after trypsin or clostripain treatment of rat chondrosarcoma proteoglycan aggregate, indicating that proteolytic digestion either removed or modified the epitope. Contrasting this, the 9/30/8-A-4 monoclonal antibody recognized an epitope present in link protein(s) 1, 2, or 3 isolated from cartilage of several animal species (rat, bovine, human, and chicken). Rat chondrosarcoma link protein 2 was digested with Staphylococcus aureus V8 protease, and the resulting peptides were fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and subjected to immunolocation analyses. The 9/30/6-A-1 and 9/30/8-A-4 monoclonal antibodies recognized epitopes in two different halves of the link protein molecule. The 9/30/8-A-4 monoclonal antibody was used to identify proteolytic cleavage peptides common to the individual link proteins (1, 2, or 3) purified from cartilage proteoglycans of several animal species. Digestion of rat chondrosarcoma link protein 2 with endoglycosidase H or alpha-mannosidase increased its electrophoretic mobility to that of link protein 3 and removed or altered the determinant recognized by the 9/30/6-A-1 monoclonal antibody, indicating that a high-mannose oligosaccharide chain was part of the antigenic determinant. The 9/30/8-A-4 monoclonal recognition of epitope was unaffected by endo- or exoglycosidase treatment. Endo- and exoglycosidase treatment of bovine nasal cartilage link proteins also altered their electrophoretic mobility, indicating that high-mannose oligosaccharide structures on the various link proteins (1, 2, or 3) accounted for the microheterogeneity observed in sodium dodecyl sulfate-polyacrylamide gels.

Animals↗
PubMed1985

Coexistence of calcitonin gene-related peptide and substance P-like peptide in single cells of the trigeminal ganglion of the rat: immunohistochemical analysis.

The localization of calcitonin gene-related peptide (CGRP) and substance P (SP) in the rat trigeminal ganglion was examined by means of the indirect immunofluorescent method. About 40% of neurons in the ganglion contained CGRP-like immunoreactivity (CGRPI), while about 20% of neurons showed SP-like immunoreactivity (SPI). In serial sections, nearly all the SPI neurons contained CGRPI.

Animals↗
PubMed1985

Immunohistochemical evidence for the coexistence of calcitonin gene-related peptide- and choline acetyltransferase-like immunoreactivity in neurons of the rat hypoglossal, facial and ambiguus nuclei.

The present immunocytochemical study demonstrates that calcitonin gene-related peptide-like immunoreactivity (CGRPI) coexists with acetylcholine in single cells of hypoglossal, facial and ambiguus nuclei. The experiments were done using alternate frozen sections from relevant regions of the rat brain. We further show that CGRPI is localized in the nerve terminals that form neuromuscular junctions in the tongue muscles.

Animals↗
PubMed1985

Neuropeptide Y-like immunoreactive structures in the rat stomach with special reference to the noradrenaline neuron system.

The origins and overall distribution of neuropeptide Y-like immunoreactive (NPYI) structures in the rat stomach were investigated by immunofluorescent staining of muscle strips from rats subjected to chemical and surgical neurotomy. The present study has demonstrated that the majority of NPYI fibers in the myenteric plexus and along the blood vessels in the muscle layers originate from NPYI cell bodies located in the celiac ganglion, which also contains noradrenaline. The remaining NPYI fibers in the circular and longitudinal muscle layer and a small number of NPYI fibers in the myenteric plexus do not contain noradrenaline and are of intrinsic origin. Noradrenaline fibers in the muscle layer are not associated with blood vessels. They originate from the celiac ganglion but do not contain NPYI structures.

Animals↗
PubMed1985

Distribution of calcitonin gene-related peptide in the rat peripheral nervous system with reference to its coexistence with substance P.

This immunocytochemical study, using a double-staining method, showed that calcitonin gene-related peptide-like immunoreactive structures are widely distributed in the peripheral nervous system and that many of them coexist with substance P-like immunoreactive structures in single sensory ganglion cells. Neurons positive for calcitonin gene-related peptide but negative for substance P were detected in sensory ganglia. These cells were large (about 30-45 micron in diameter); these primary sensory neurons containing calcitonin gene-related peptide can probably act independently of substance P. There were neurons containing calcitonin gene-related peptide without substance P in the pterygopalatine ganglion, although these cells were less numerous than in the sensory ganglia. In consecutive sections, calcitonin gene-related peptide-like structures occurred in thyroid parafollicular cells, which also contain calcitonin. This suggested that messenger RNA for producing calcitonin gene-related peptide is also present in the thyroid, and like calcitonin, calcitonin gene-related peptide may have a peripheral physiological role.

Animals↗
PubMed1985

Characterization of the in vivo RNA product of the pOUT promoter of IS10R.

We characterized a single RNA species (RNAout1) which was the major in vivo RNA made from pOUT of IS10R. RNAout1 was 70 nucleotides long; its 5' end corresponded exactly to the in vitro start of pOUT transcription. The concentration of RNAout1 was estimated at 5 to 10 molecules per cell containing the single-copy plasmid NR1. RNA sequences from pOUT of IS10L were detected at a much lower (less than one molecule per cell) steady-state concentration and may be preferentially degraded in vivo. We suggest that the low level of the IS10L transcript led to the inability of IS10L sequences to translationally inhibit Tn10 transposition.

Base Sequence↗
PubMed1985

Supraclinoid intracarotid chemotherapy using a flow-directed soft-tipped catheter.

In an attempt to avoid toxic reactions of the eye as a complication of internal carotid arterial infusion of cisplatin, carmustine, or a combination of both for the treatment of brain tumors, a new Gore-Tex/Teflon coaxial catheter system has been used for supraclinoid placement. Catheter placement was successful in 14 of 16 attempts in eight patients. Two patients experienced eye pain and conjunctivitis--a result of the chemotherapeutic agent leaking through the Gore-Tex portion of the catheter at the infusion rate of 170 ml/h. No complications were noted as long as the infusion rate was maintained at 125 ml/h or lower.

Adult↗
PubMed1985

Aspects of immunobiology and immunotherapy and uses of monoclonal antibodies and biologic immune modifiers in human gliomas.

Recent progress in brain tumor biology research has helped us to understand the causes of our failure to improve patient survival with current therapeutic approaches. Present combination regimens of surgery, radiotherapy, and chemotherapy fail to address adequately two inherent biologic properties of brain tumors: tumor-induced host immunosuppression and tumor cell heterogeneity. Future success in immunotherapy will depend on our ability to dissect the mechanisms involved in tumor-host interactions. Also, therapies may have to be individualized. The potential for MAs in research and clinical application is great owing to their unlimited discriminative power for molecular and functional characterization. Differential diagnosis of difficult cases, such as parenchymatous tumors or neoplastic cells in CSF, with panels of MAs will be available in the near future. The use of MAs to direct localization and therapy of brain tumors is also promising, as evidenced by the preliminary data from our laboratory and from those of other workers. Other applications of MAs, such as prevention of invasion and metastasis by targeting cell surface molecules involved in cell-matrix attachment function, are also under study. Future refinement in MA-specificity and in enhancement of MA-delivery to tumor sites will significantly complement new therapeutic approaches. As brain tumors evade immunosurveillance through active participation in inducing tumor-specific immunosuppression, successful immunotherapy, either passive serotherapy or active immunization, will be best achieved in patients with a slight or moderate immunosuppressive state. Alteration of immune status with various biologic response modifiers to boost host reactivity against tumors will be an important adjunct in our arsenal against brain tumors. IFNs, with their direct tumoricidal activity, and lymphokines (such as interleukin-2) may be such reagents with a promising future.

Antibodies, Monoclonal↗
PubMed1984

Tandem promoters preceding the gene for the M1 RNA component of Escherichia coli ribonuclease P.

The nucleotide sequence of a cloned gene for the RNA component of Escherichia coli ribonuclease P, M1 RNA, is presented. The sequence determined extends 320 nucleotides upstream of the 377-base-pair (bp) structural gene and includes three sequences homologous to the consensus E. coli promoter sequence. Two nucleotides found in the M1 RNA structural gene sequence were not found in a previously determined gene sequence of another M1 RNA clone [Reed, R. E., Baer, M. F., Guerrier-Takeda, C., Donis-Keller, H. & Altman, S. (1982) Cell 30, 627-636]. In vitro transcription of supercoiled plasmid DNA containing the M1 RNA gene resulted in a major transcript arising from the strong promoter nearest to the mature M1 RNA. RNAs encoded by the M1 RNA clone in vivo were examined by S1 nuclease mapping. The results indicated that in vivo transcripts originate from all three promoters preceding the M1 RNA gene. These transcripts are apparently processed in a multistep pathway to generate the 5' end of mature M1 RNA.

Base Sequence↗
PubMed1984

Chronobiology of Aging in Albizzia julibrissin: I. An Automated, Computerized System for Monitoring Leaflet Movement; The Rhythm in Constant Darkness.

We are using leaflet movements in Albizzia julibrissin as a model system for investigating the chronobiology of aging. To monitor leaflet movements during long dark periods with adequate temporal and spatial resolution, we designed an automated, computerized photoelectric monitoring system. Each of 12 leaflet pairs was positioned in an individual light-proof container, with one leaflet immobilized. The angle of the mobile leaflet was monitored by a photosensor array using a low intensity infrared beam. Leaflet position was determined by custom-developed software, using information on the shading patterns of the sensors. Data on leaflet angle as a function of time were collected and stored on a floppy disc and then printed in numerical and graphical form.Oscillations of young, middle-aged, and old leaflets persist during 7 d of darkness with a periodicity close to 24 h. Period length appears to be age-independent, but rhythmic wave form is age-dependent. The older the leaflet, the earlier and more completely it opens and the less completely it closes.

Journal Article↗