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Biomedical subjects

G Mathé

Publications and source records attributed to G Mathé.

At least 127 records · Page 7Linked to original sources

Correlated ultrastructural and immunological findings in CD8+ and CD4+ peripheral T-cell lymphomas.

Ultrastructural features of CD8+ and CD4+ peripheral T-cell lymphomas were studied and the results revealed distinct traits correlated with phenotype. CD8+ peripheral T-cell lymphomas were characterized by a rich organular pattern with a well-developed Golgi apparatus, dense granules, numerous and atypical giant mitochondria. CD4+ peripheral T-cell lymphomas were characterized by wide cytoplasmic areas devoid of organelles. Since similar ultrastructural features differentiated normal and pathological CD8+ and CD4+ peripheral T-lymphocytes, we conclude that under both normal and pathological conditions the expression on the part of the peripheral T-lymphocytes of CD8+ and CD4+ phenotypes is associated to morphological features which distinguish the two subsets.

Adult↗

Presence of human papilloma virus types 16 and 18 in genital warts and cervical neoplasias.

Certain types of human papilloma viruses (HPV) are associated with human genital proliferative diseases, and among them HPV16 and HPV18 seem to play an important role in the occurrence of cervical cancer. We used restriction enzyme analysis and molecular hybridization, in order to investigate the type of viral infection and the physical state of viral DNA in gynecological benign, pre-malignant and malignant lesions. HPV6/11 specific sequences could only be detected as episomes and this in benign lesions classified as condylomata acuminata. On the other hand, HPV16 and HPV18 sequences were detected in non-malignant lesions such as flat condylomata (7 out of 14 cases), pre-malignant lesions including cervical intra-epithelial neoplasias (10 out of 20 cases), and most frequently in cervical invasive cancers (21 out of 27 cases). In a large number of virus-positive cases, HPV16 and HPV18 could only be discerned in forms consistent with the existence of episomes and/or randomly integrated head-to-tail oligomers. However, some invasive carcinomas and cervical intra-epithelial neoplasias contained, in addition, clonal outgrowths with detectable virus-cellular junction fragments of the integrated viral genomes. In the light of these data, monitoring the type of viral infection proves to be an important adjunct to histological analysis when assessing those patients affected by condyloma or cervical intra-epithelial neoplasia who are at risk for developing invasive carcinoma.

Carcinoma↗

Seasonal modulation of the circadian time structure of circulating T and natural killer lymphocyte subsets from healthy subjects.

A seasonal modulation of the circadian time structure of circulating T and natural killer (NK) lymphocyte subtypes was documented in five healthy men aged 24-36 yr. Venous blood was obtained every 4 h for 24 h from each subject in January, March, June, August, and November 1984. Three subjects were also studied in April and/or August and/or November 1983 for the T subsets only. Mononuclear cells were isolated on Ficoll-Paque gradient and aliquots were incubated with OKT3, OKT4, OKT8, or HNK-1 monoclonal antibodies for characterizing all, T, T helper, T suppressor-cytotoxic, and NK lymphocytes, respectively, under an epifluorescence microscope. An effect of both sampling time and study month was statistically validated (P less than 0.01) with both two-way analysis of variance and cosinor for the peripheral counts in total, pan-T, T helper, and NK lymphocytes (cells per cubic millimeter). Seasonal changes affected both the circadian patterns and the 24-h mean values. Thus the double amplitude (total extent of variation) of the circadian rhythm in circulating total, T and T helper lymphocytes varied between 0 in March (P greater than 0.30; no rhythm) and up to 46-68% of the 24-h-mean (M) in November, with acrophases (times of maximum, 0) localized in the first half of the night (P less than 0.001). Maximal values were found at 8:30 h for both T suppressor-cytotoxic and NK lymphocytes; a smaller second peak was also found at 20:30 h, and a 12-h rhythm was validated by cosinor (P less than 0.0001), with no patient change in waveform along the year scale. A circannual rhythm was statistically validated by cosinor for total (0 in November), pan-T (0 in March), T suppressor-cytotoxic (0 in December), and NK lymphocytes (0 in October). A rhythm with a period equal to 6 mo was found for circulating T helper cells with 0 occurring both in April and October. Seasonal variations in the incidence of several immunologically related diseases may correspond to an endogenous circannual time structure.

Adult↗

AIDS: from exact data to beginning of optimism.

We have compiled epidemiologic data on AIDS which failed to support systematic screening for HIV viruses and which allow a certain optimism regarding the future of the epidemic: there seems to be, in New York, a decrease in the frequency of affected homosexuals, probably because they have followed advice on hygiene. Hence, the systemic, pleiomorphic, HIV infectious disease which might include, in addition to AIDS (35%), the forms where different organs are directly affected, is developing into a heterosexual disease affecting drug addicts and their sexual partners. The therapeutic paradigm is underlined. It is unacceptable that those drugs which have proven effective against the virus, or immune functions, should not be used in combination, on account of some of them still being at a trial stage, that is, administered individually and compared to a placebo, after randomization.

Acquired Immunodeficiency Syndrome↗

Human thymic epithelium in culture: an experimental model for the study of thymic microenvironment.

The thymus plays a central role in the differentiation of T-lymphocytes. During the past years several in vitro models have been developed for the elucidation of the functional role of different thymic stromal cells. After reviewing the literature, the authors discuss: a) the in vivo and in vitro data on the structural organization of the thymus microenvironment, with particular reference to the epithelial cells; b) the endocrine function of the thymus; c) the interaction between the thymic epithelium and T-cell precursors. The experimental approaches to these problems are also discussed. In particular, the authors examine in detail the experimental aspects which are at present under investigation in their laboratories.

Animals↗

Scientific criticisms of the comparison of exponential survival and disease-free survival curves.

Scientific criticism when analyzed in depth, appears to be as exacting as ethical criticism of statistics relating to adjuvant therapy comparative trial results, based on survival or on length of first remission. The heterogeneity of a population in which an exponential curve represents survival or period of disease-free survival (OFS) raises the issue of the significance of a benefit or absence of benefit provided by studied treatment. The segmentation of exponential curves into two or three slopes is proposed. This permits a more accurate evaluation of the results, as well as the application of several protocols, adapted to separate homogeneous groups of patients.

Antineoplastic Agents↗

Cancer "cures" in children, adolescents and young adults versus general cancer cure failure after 50 years of age.

Cancer cure has principally concerned stem cell or embryonic cell tumors in children, adolescents and adults under 50 years of age. Cancers that are termed "curable" are those in which the patient survival curve rapidly becomes parallel to the normal life expectancy curve--a plateau in children--and "almost curable" those in which this phenomenon appears later on and/or which is not completely parallel to the normal life expectancy curve. The failure to cure cancer patients over 50 years of age by chemotherapy suggests that although cytostatics are able to reduce the neoplastic cell number to a level that can be eradicated by the lato sensu immunologic functions of the organism before that age, this is not the case in older patients in which even a low number of neoplastic cells cannot be destroyed in this manner. Experimental and clinical data on preventive and curative effects of immuno-restoration/stimulation after the age of 50 are presented and discussed, as well as both reduced cancer patient survival rate and decreased immunity which follows peri-surgical radiotherapy.

Adolescent↗

Importance of age and methotrexate dosage: prognosis in children and young adults with high-grade osteosarcomas.

The disease-free survival (DFS) in 87 patients with high-grade non-metastatic osteosarcoma of the limbs treated in 3 consecutive pilot studies was compared. From 1978-1982 (Group 1), 41 patients were treated after surgery by adjuvant chemotherapy alternating 2 non-cross resistant cyclic combinations each month for 1 year and early prophylactic lung irradiation. From 1982-1984 (Group 2), preoperative chemotherapy 2-drug combination: adriamycin-cisplatinum (ADR-CDDP) was tested in 20 patients. Surgery was followed by 3 treatment periods of the same combination. From 1984-1987 (Group 3), 26 patients were treated according to modified T-10 protocol with high-dose methotrexate (HDMTX) adapted to age and individual pharmacokinetics. In Group 1, the overall 5 yr DFS was 63% (average follow-up 60.6 months). The worst prognostic factor was low age: 5 yr, DFS under 15 yr was 30%; greater than 15.5 yr, DFS was 85%. The second negative prognostic factor was failure to give sufficient MTX in patients greater than 15 yr. In Group 2, the actuarial 3 yr DFS was only 35% and a low age was still a negative prognostic factor. In Group 3, the 2 yr DFS was 90%, confirming Rosen's results. With HDMTX adapted to age and individual pharmacokinetics, age was no longer a negative prognostic factor. We concluded that HDMTX has a positive effect in the treatment of osteosarcomas in young people; furthermore, in very high doses, as determined by individual pharmacokinetics. In adults, postoperative chemotherapy eventually including moderate doses of MTX, can be effective and may be better tolerated.

Adolescent↗

From Fernand Widal rhinitis syndrome and chronic sinusitis to total muco-ciliary disease.

It is claimed that 25% of the total population show symptoms of a muco-ciliary chronic sinusitis, presenting as a posterior catharrh that can be confirmed by computerized tomography and by prolonged sinuso-nasal saccharine clearance. This manifestation of the mucus ciliary transport syndrome may be associated with other disorders (rhinitis, otitis, bronchitis, irritable colon, sterility and dextrocardia). The role of aspirin and intolerance to other drugs or chemicals especially anti-inflammatory drugs, has been implicated. Acid air pollution may play a part, as the respiratory mucus does not tolerate an acid pH. Alkaline aerosols and theophyllin which activates cilia mobility, usually increase mucus fluidity and facilitate its clearance from the sinuses.

Chronic Disease↗