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Biomedical subjects

J Ngan

Publications and source records attributed to J Ngan.

7 recordsLinked to original sources
PubMed1989

Factors influencing the development of gastrointestinal complications after neurosurgery: results of multivariate analysis.

A retrospective review of 526 patients who underwent neurosurgery for nontraumatic conditions over a 5-year period revealed 36 (6.8%) patients with endoscopically and or surgically documented postoperative gastrointestinal (GI) complications. Two patients had GI bleeding and perforation, and the remaining patients had bleeding only. Multivariate analysis indicated 5 factors that were of independent significance in predicting the development of postoperative GI complications. These factors included 1) inappropriate secretion of antidiuretic hormone, 2) preoperative coma (Glasgow Coma Score less than 9), 3) the presence of postoperative complications, 4) age greater than or equal to 60 years, and 5) pyogenic infection of the central nervous system. Further analysis of the 36 patients with GI complications revealed that they could be divided into three groups with different clinical courses. In Group I (n = 10), all patients died as a result of their neurological conditions; GI complications were just preterminal events and did not require treatment. In Groups II (n = 11) and III (n = 15), GI complications were symptomatic and life-threatening events, respectively. Eleven patients from Group III died as a direct result of the GI complications. Separate multivariate analyses based on the patients in Groups II and III revealed that preoperative coma was the only significant factor that predicted the occurrence of life-threatening complications. Patients who are at high risk of developing postoperative GI complications can thus be identified, and intensive prophylaxis may be instituted.

Brain Diseases↗
PubMed1979

Suppression of IgE antibody formation in mice: requirement for T-T lymphocyte interaction.

Norman SWR mice injected with syngeneic spleen cells from ovalbumin (Ov)-primed mice were unable to make IgE anti-Ov antibodies when challenged with alum-pertussis-Ov. Immune T lymphocytes were shown to be responsible for the inhibitory effects of adoptively transferred spleen cells. Treatment of recipient mice with mild x-irradiation or with cyclophosphamide 2 or 3 days before cell transfer resulted in abrogation of the suppressor effect of immune cells. The injection of T lymphocytes into x-irradiated milce restored the suppressive effect of immune cells. It thus appears that immune T cells provide the stimulus for activation of suppressor T cells of the host. Although the generation of suppression is antigen-specific, the expression of suppression appears to be nonspecific.

Alum Compounds↗
PubMed1978

Suppressor T cells for IgE and IgG in Peyer's patches of mice made tolerant by the oral administration of ovalbumin.

A single oral dose of ovalbumin (Ov) resulted in inhibition of IgE formation in mice subsequently immunized i.p. with Al(OH)3-Ov. Repeated feeding of Ov (on alternate days for 2 weeks) induced the formation of detectable suppressor cells in Peyer's patches and spleen. Suppression was demonstrated by the ability of adoptively transferred Peyer's patch or splenic lymphocytes from Ov-fed tolerant mice to inhibit IgE formation in Ov-immunized syngeneic recipients. Suppressor cells could be induced by feeding mice as little as 100 microgram of Ov on alternate days for 2 weeks. Suppression was specific and Peyer's patch lymphocytes were shown to be more effective suppressors than splenic lymphocytes.

Administration, Oral↗
PubMed1976

Induction and suppression of reagins in the neonatal mouse.

Neonatal SWR mice are capable of synthesizing reagins when immunized with a mixture of concanavalin and ovalbumin or a mixture of Bordetella pertussis, alum and ovalbumin. Reaginic antibody-forming cells can be found in the spleen, lymph nodes, bone marrow and Peyer's patches. Tolerance with respect to IgE can be induced by the injection of deaggregated ovalbumin into neonatal mice.

Animals↗
PubMed1976

The suppressive effect of the interferon on the ability of mouse spleen cells synthesizing IgE to sensitize rat skin for heterologous adoptive cutaneous anaphylaxis.

Mouse spleen cells which are synthesizing IgE can sensitize rat skin for HACA. When such cells are treated with mouse interferon, their ability to sensitize rat skin is reduced or completely inhibited. Two hundred PRD50 units of interferon reduced HACA reactions by more than 50%; 600 units gave complete inhibition. Interferon may act by inhibiting IgE synthesis and/or release.

Animals↗