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Biomedical subjects

E Tan

Publications and source records attributed to E Tan.

At least 127 records · Page 7Linked to original sources
PubMed1985

Vasopressor neurons in the rostral ventrolateral medulla of the rabbit.

Neurons within the rostral ventrolateral medulla oblongata project directly to the intermediolateral column in the thoracolumbar spinal cord. This paper reviews evidence obtained from experiments in the rabbit regarding the anatomical connections and physiological, pharmacological and histochemical properties of these cells. The following hypotheses are discussed: an increase in the firing rate of these neurons leads to a rise in arterial pressure due to sympathetic vasoconstriction, but does not affect respiratory or other somatomotor activity; the bulbospinal pathway originating from these neurons is an essential component of the central pathways mediating baroreceptor and other cardiovascular reflexes; these neurons receive tonic GABAergic inhibitory inputs, which are not all of baroreceptor origin; many of these bulbospinal neurons synthesize adrenalize. The possible role of adrenaline in the function of these neurons is considered.

Animals↗
PubMed1984

Identification of cardiovascular cell groups in the brain stem.

There is now good evidence that there are several distinct groups of cells in the brain stem that are capable of inducing marked changes in cardiovascular function. This paper briefly reviews the results of recent experiments which have identified cardiovascular cell groups in the rostral ventrolateral and dorsomedial medulla, and in the periaqueductal grey and ventral tegmentum of the midbrain. Results of our experiments as well as those of others suggest that excitation of cardiovascular cell groups in the lower brain stem leads to an undifferentiated generalized increase or decrease in sympathetic activity, whereas excitation of certain midbrain cell groups can evoke a highly co-ordinated pattern of autonomic and respiratory changes that closely resembles the pattern associated with certain behaviours in the conscious animal.

Animals↗
PubMed1983

Identification of a La protein binding site in a RNA polymerase III transcript (4.5 I RNA).

Anti-La antibodies are frequently found in patients with autoimmune diseases; the antigen was reported to be a 50,000-Da protein (Rinke, J., and Steitz, J. A. (1982) Cell 29, 149-159). Because this protein was associated with many nascent RNA polymerase III transcripts, it was suggested to be an RNA polymerase III transcription factor. The present study was designed to analyze 4.5 I ribonucleoprotein, an RNA polymerase III transcript which contains the La antigen. It was found that the 3'-end 20-30-nucleotide portion was the most protected portion of 4.5 I RNA when 4.5 I ribonucleoprotein was digested with T1 RNase. When U2 RNA (an RNA polymerase II transcript) and 4.5 I RNA were incubated with the S-100 fraction of Novikoff hepatoma cells, the 4.5 I RNA bound La antigen but the U2 RNA did not. When partial and complete T1 RNase digestion fragments of 4.5 I RNA were incubated with the S-100 fraction, the 3'-end fragments bound preferentially to the La antigen. However, the fragments of 4.5 I RNA bound less efficiently to La antigen than whole 4.5 I RNA. These results indicate that the 3'-end of 4.5 I RNA is the La antigen binding site in this molecule and suggest that the overall conformation of RNA aids in the binding of La antigen.

Animals↗
PubMed1983

Proliferating cell nuclear antigen (PCNA) and human malignant tumor nucleolar antigens (HMTNA) in nucleoli of human hematological malignancies.

Lymphoma (Lymphocytic non-Hodgkin's malignant lymphoma) and leukemic (chronic lymphocytic, acute and chronic myeloid, myelomonocytic leukemia) cells were studied by indirect immunofluorescence to evaluate the presence of proliferating cell nuclear antigen (PCNA) and human malignant tumor nuclear antigen (HMTNA) in their nucleoli. Most cells in lymph node smears of lymphocytic non-Hodgkin's malignant lymphoma (NHML) developed a bright nucleolar fluorescence with HMTNA antibodies. PCNA was detected in nucleoli of a limited number of cells which apparently represent the proliferating cell population in these lymphomas. Similarly, in the bone marrow smears of patients with chronic lymphocytic leukemia most cells possessed a nucleolar fluorescence for HMTNA and PCNA was present in nucleoli of a limited number of cells. In the bone marrow smears of patients with myeloid or myelomonocytic leukemias most blastic or monocytoid cells also developed a bright nucleolar fluorescence with HMTNA antibodies and PCNA was present only in a small percentage of these cells. Leukemic cells with PCNA in their nucleoli like thekhuntigen might represent a proliferating cell population in late G1-early S phase.

Antigens, Neoplasm↗
PubMed1983

Anticytoplasmic antibodies in antinuclear antibody-negative lupus erythematosus. Correlation with clinical course.

A patient with clinical manifestations of systemic lupus erythematosus (SLE) and without antinuclear antibodies was found to have anticytoplasmic antibodies. These anticytoplasmic antibodies were directed against ribosomal ribonucleoprotein, and the titer of anticytoplasmic and anti-ribosomal ribonucleoprotein antibodies correlated with the clinical course of the patient's illness. The importance of detecting anticytoplasmic antibodies and their role in producing disease in patients with SLE is discussed.

Adolescent↗
PubMed1983

Antinuclear antibodies in Utah coal miners.

Antinuclear antibodies (ANA) were detected using a mouse kidney substrate in 69 of 238 (29 percent) underground Utah coal miners at a titer of 1:16. At titers of 1:4 and higher, 52 percent were positive. The majority had a speckled pattern and were not directed against any previously characterized antigens. Fifteen of 28 with high titer ANA had reduced complement. The ANA was more apt to be present in those with coal workers' pneumoconiosis (CWP), and as ANA titer increased, the percentage with CWP increased. The ANA increased with both age and coal mine dust exposure. It is hypothesized that ANA and CWP both result from long-term dust exposure, but that there is insufficient evidence to implicate ANA in the pathogenesis of CWP.

Age Factors↗
PubMed1982

Free bowel transfer for pharyngo-oesophageal reconstruction: an experimental and clinical study.

The use of a free bowel transfer to reconstruct pharyngo-oesophageal defects can only be accepted if the surgeon can guarantee that the microvascular techniques are near perfect. Experimental work in dogs demonstrates that high patency and graft survival rates can be achieved. The effectiveness of this technique in reducing morbidity and fistula formation is due to the rich blood supply to the graft which ensures sound and rapid healing. A case report is presented, demonstrating how quickly a patient can be rehabilitated after a radical pharyngo-laryngectomy.

Aged↗
PubMed1982

Deficient catecholamine release as the basis of orthostatic hypotension in pernicious anaemia.

A patient with peripheral neuropathy and orthostatic hypotension was found to have pernicious anaemia. Symptoms improved after vitamin B12 replacement therapy. Insulin tolerance testing showed that the patient lacked catecholamine, heart rate, and sweating responses to hypoglycaemia. This indicates that pernicious anaemia may cause orthostatic hypotension owing to failure of noradrenaline release.

Aged↗
PubMed1981

Kinetochore structure, duplication, and distribution in mammalian cells: analysis by human autoantibodies from scleroderma patients.

The specificity of the staining of CREST scleroderma patient serum was investigated by immunofluorescence and immunoelectron microscopy. The serum was found to stain the centromere region of mitotic chromosomes in many mammalian cell types by immunofluorescence. It also localized discrete spots in interphase nuclei which we have termed "presumptive kinetochores." The number of presumptive kinetochores per cell corresponds to the chromosome number in the cell lines observed. Use of the immunoperoxidase technique to localize the antisera on PtK2 cells at the electron microscopic level revealed the specificity of the sera for the trilaminar kinetochore disks on metaphase and anaphase chromosomes. Presumptive kinetochores in the interphase nuclei were also visible in the electron microscope as randomly arranged, darkly stained spheres averaging 0.22 micrometers in diameter. Preabsorption of the antisera was attended using microtubule protein, purified tubulin, actin, and microtubule-associated proteins. None of these proteins diminished the immunofluorescence staining of the sera, indicating that the antibody-specific antigen(s) is a previously unrecognized component of the kinetochore region. In some interphase cells observed by both immunofluorescence and immunoelectron microscopy, the presumptive kinetochores appeared as double rather than single spots. Analysis of results obtained using a microspectrophotometer to quantify DNA in individual cells double stained with scleroderma serum and the DNA fluorescent dye, propidium iodide, led to the conclusion that the presumptive kinetochores duplicate in G2 of the cell cycle.

Animals↗
PubMed1980

Interstitial nephritis in a patient with atypical Sjögren's syndrome.

A patient was observed with interstitial nephritis which resulted in renal tubular acidosis (distal type), tubular proteinuria and defective urinary concentrating ability in the absence of edema, elevated arterial blood pressure, glomerular proteinuria or abnormal urinary sediment. The presence of interstitial nephritis was established by renal biopsy which showed dense infiltrates in the interstitium, interstitial fibrosis and thickening and splitting of the pericapillary basal membranes. Immunofluorescence was non contributory. Extrarenal symptoms were discrete (arthralgia of both hands, Raynaud's syndrome upon cold exposure). Mixed connective tissue disease (MCTD) was suspected because of a positive ANF test (speckled pattern), which was completely abolished by ribonuclease pretreatment. However, in hemagglutination tests, no antibodies against ribonuclear protein (ENA) could be demonstrated. The diagnosis of Sjögren's syndrome was established by demonstration of antibodies against SSA and SSB antigens. The observation suggests that in patients with interstitial nephritis the diagnosis of Sjörgren's syndrome must be considered even if extrarenal symptoms of Sjögren's disease are minimal or lacking. The diagnosis can be established with recent serological techniques.

Adult↗
PubMed1979

Microvascular surgery in maxillo-facial reconstruction.

The recent advances in microvascular surgery have been applied to maxillo-facial reconstruction in the area of the lower jaw and soft tissue of the face. Five cases are presented, demonstrating some of the techniques and results in patients suffering from congenital, post-traumatic and post-cancer resection deformities.

Adult↗
PubMed1978

A de-epithelialized free groin flap for facial contour restoration.

The transfer of de-epithelialized free groin flaps to restore facial contour after tumour resection and in hemifacial microsomia is described. The flap can be transferred in one stage and remodelled at a later minor operation. This provides an acceptable alternative to the other more difficult and often less successful methods of restoring soft tissue deficiencies of the face.

Adolescent↗