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Biomedical subjects

N Hanna

Publications and source records attributed to N Hanna.

144 records · Page 8Linked to original sources
PubMed1975

Inhibition of T- and B-lymphocyte functions by normal immunosuppressive protein.

Normal immunosuppressive protein (NIP) isolated from human plasma was studied in two well defined systems. (1) Spontaneous rosettes of sheep red blood cells with human peripheral blood lymphocytes and PHA-induced lymphocyte cytotoxicity as indicators for T-cell function. (2) Rosette formation tests of human lymphocytes with antibody-coated erythrocytes or erythrocytes coated with antibody and complement as well as antibody-induced lymphocyte-mediated cytotoxicity represented non-T-cell activity. While NIP did not inhibit the formation of any of the above mentioned rosettes, it practically prevented both PHA-induced and antibody-mediated lymphocyte cytotoxicity. Relatively small amounts of NIP inhibited PHA-induced cytotoxicity while higher doses were required for the inhibition of antibody-mediated lymphocyte cytotoxicity. Possible mechanisms of its suppressive activity are discussed. NIP was found to be heat-stable and did not show any species specificity, as NIP preparations from human plasma were immunosuppressive in human, mouse and guinea-pig systems.

Alpha-Globulins↗
PubMedDate not supplied

Detection of human papillomavirus DNA in the urogenital tracts of men with anogenital warts.

Increasing evidence suggests that human papillomavirus (HPV) infection of the female anogenital tract is multifocal. Less is known of the distribution of HPVs in men. To investigate this, a prospective study was conducted of 116 men consecutively attending a clinic for ablative treatment of anogenital warts. Wart tissue, urethral swabs, and urine were obtained from each patient. HPV DNA was extracted from the specimens and amplified using the polymerase chain reaction (PCR). HPV types 6, 11, 16, 18, 31, and 33 were identified using Southern blotting of the PCR product, followed by hybridization. HPV DNA was detected in 112 (96.6%) of 116 wart specimens and there was urethral infection with HPV in 26 (22.4%) of the men. Eleven (61.1%) of 18 urethral specimens taken with a loop and 22 (20.0%) of 116 urethral specimens taken using a cotton-tipped swab contained HPV DNA. One (6.3%) of 16 urine samples tested contained HPV DNA. HPV types 6 and 11 were found in the urethra most commonly when warts were seen near the urinary meatus, although HPV occurred in the urethras of men without clinically apparent meatal warts. The proportion of urethral samples with HPV DNA, including HPV types 16, 18, 31, and 33, was independent of the location of visible warts at the time of sampling.

Adolescent↗
PubMedDate not supplied

[Evaluation of a new automatic hematological system: the Advia 70 (Bayer-Diagnostics)].

The Advia 70 hematology system is a new automated analyser manufactured in Texas (USA) by MWI-DANAM and marketed by Bayer- Diagnostics in France. The throughput is 70 complete blood counts (CBC) with leukocyte differential counts (diff) per hour. Three sample modes are proposed: normal mode (180 muL of whole blood), sample saver mode (90 muL) or automatic sampler (180 muL). The principles used on Advia 70 are: 1) electrical impedance for cell counting (WBC, RBC, platelets, MCV) and RBC/plt sizing; 2) multi-dimensional optical system and absorbance for white cell differential. The Advia 70 has been evaluated in our laboratory over a three-week period. Within-run variations of blood counting (CBC & diff) were determined on normal and abnormal patient specimens whereas between run-variations were determined on normal controls. Linearity and detection limits were also tested. The Advia 70 system results were reproducible and reliable. The correlations between the various sample modes were very good. Contamination and store assays were performed. Thirty normal and abnormal samples were successively analysed on the Advia 70 system and on the Advia 120 system which methodologies are different (myeloperoxidase staining coupled with flow cytometry-nuclear lobularity analysis for WBC/Diff, flow cytometry and laser diffraction for RBC/platelets), and the results were compared: despite the different technologies used on both analysers, the correlations were very good (CBC and diff parameters). Finally, we evaluated the leukocyte differential flags on 72 patients samples with abnormal cells, using the blood smear examination as the reference method. In conclusion, the Advia 70 can be used in private and hospital laboratories.

Autoanalysis↗
PubMedDate not supplied

Inflammation and recruitment of immune cells into the lung.

The mechanisms responsible for recruitment of antibody-forming cells (AFC) into lung lobes exposed to antigen are not known. Because instillation of antigen induces inflammation, AFC may enter immunized lung lobes by changes in vascular permeability and/or in response to the release of mediators. The purposes of this study were to evaluate inflammatory responses produced by particulate antigens or interleukin-1 (IL-1) and to examine the recruitment of AFC and lymphocytes into the lung in response to these inflammatory stimuli. Two peaks of inflammation were observed in the lung lobes of dogs exposed to sheep red blood cells (SRBC), one at 1 day and the second around 9 days after instillation. Lymphocytes did not enter the lung during the first inflammatory response. However, lymphocytes and anti-SRBC AFC did enter immunized lung lobes during the second inflammatory response. AFC and lymphocytes also entered a lung lobe instilled with rabbit red blood cells (RRBC) at 6 days after immunization with SRBC. The observation that lymphocytes did not enter at 1 day after instillation of SRBC, but did enter the RRBC lung lobe at 1 day after instillation of RRBC, suggested that a population of lymphocytes, including AFC, were present in blood several days after immunization with SRBC that were capable of entering sites of inflammation in the lung. Instilled IL-1 was chemotactic in vivo for neutrophils and induced inflammation in the lung. However, IL-1 was not directly chemotactic for AFC or lymphocytes in vivo.

Animals↗
PubMedDate not supplied

Regulation of natural killer cell activation: implementation for the control of tumor metastasis.

The cellular interactions that regulate natural killer (NK) cell-mediated cytotoxicity and antimetastatic activity following treatment with biological response modifiers (BRM) were studied. The transient activation of NK cells by a single injection of Corynebacterium parvum is followed by a refractory period during which a second injection of BRM fails to stimulate the already depressed NK cell activity. During this hyporesponsive period, the in vivo NK cell-dependent BRM-induced antimetastatic activity is markedly reduced and cannot be enhanced by multiple injections of BRM. A correlation exists between the generation of hyporesponsiveness to NK cell activation and the activation of suppressor macrophages by C. parvum. BRM that selectively activate NK cells without subsequently activating suppressor macrophages do not induce hyporesponsiveness to further activation of NK cells in vivo and, when given in multiple injections, retain the ability to inhibit hematogenous tumor metastasis.

Animals↗