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Biomedical subjects

G David

Publications and source records attributed to G David.

At least 271 records · Page 15Linked to original sources
PubMed1981

Study of a group of 484 fertile men. Part II: relation between age (20-59) and semen characteristics.

Commonly measured semen variables as well as post-thaw motility have been studied as a function of age in fertile men. The mean age was 34.6 (SD = 6.6). No significant change with age was found for the sperm count, semen volume or total number of spermatozoa. Conversely, there were significant differences between age groups for the percentage of normal cells (P less than 0.01) and the percentage of motile forms (P less than 0.01) as well as for the after-thaw motility (P less than 0.001). These three variables rise, reach a maximum level at 30 to 35 years of age and then decrease. These changes are not explained by variations in the length of abstinence.

Adult↗
PubMed1981

Basal lamina formation by normal and transformed mouse mammary epithelial cells duplicated in vitro.

Cells from low-passage (LP) cultures of a mouse mammary epithelial line (NMuMG cells) form a basal lamina when they are cultured on a type I collagen gel substratum. A high-passage (HP) strain of this line maintained the morphologic, serologic, and karyologic properties of the LP cells. For the determination of whether transformation of the NMuMG cells might lead to defects in the basal lamina, cells from LP cultures were compared in vivo and in vitro with cells of HP cultures for tumorigenicity, growth characteristics, and ability to form a lamina. The LP NMuMG cells had a typical epithelial morphology and showed no cytologic evidence of cancer. They formed an ultrastructurally normal continuous basal lamina in vivo when they were injected into athymic nude mice. In contrast, the HP cells were pleomorphic and highly invasive when injected into nude mice where they showed frequent and large basal lamina defects. These cells also accumulated only traces of lamina-like materials when cultured on a collagen gel, indicating that neoplastic transformation had markedly reduced the ability of NMuMG cells to form a basal lamina both in vivo and in vitro. Because the collagen gel culture system duplicated the in vivo situation with regard to basal lamina integrity, the basis for this lack of in vitro basal lamina formation may be physiologically relevant for the mechanism of malignant invasion.

Animals↗
PubMed1981

[Carotid loops and folds, one of the limitations of the Doppler examination (author's transl)].

Lesions in the form of loops and folds occur frequently in carotid pathology. Different authors have assessed their responsibility for the occurrence of ischaemic cerebral accidents at between 20% and 16%. Diagnosis of the condition by Doppler exploration of such abnormal cases is certainly of value, but is subject to numerous sources of error. The present authors have defined the different types of lesions, their pathogenic aetiology and their repercussions on the blood indices. The various changes occurring in Doppler tracings have been discussed in relation to these anatomical types of carotid lesions and in relation to the arteriographic pictures.

Carotid Artery Diseases↗
PubMed1980

[Methodological approach of a retrospective study on 484 fertile and 2 768 infertile men (author's transl)].

One possible method to study male factors in fertility is the retrospective comparison of groups of fertile and infertile men. Such a study based on 484 fertile and 2 768 infertile men enables us to point out an increasing risk of infertility with decreasing sperm counts and percentage of motile spermatozoa and with increasing abnormal forms. However the increase in relative risk is sharper for the patients who consulted twice or more than those who came for the first time. This difference might in part be explained by the fact that the former had a longer duration of infertility or that the couple infertility had less often a female origin. Consequently detailed information on this subject must be taken into account in studies on fertility.

Fertility↗
PubMed1980

The success of A.I.D. and semen characteristics: study on 1489 cycles and 192 ejaculates.

A comparison was made between successful (167) and unsuccessful (1322) insemination cycles in order to evaluate the role in conception of different semen characteristics. The most important semen variable was found to be post-thaw motility: the success rate per cycle increased from 7% when post-thaw motility was less than or equal to 40% to 17% when it was greater than or equal to 65%. Multiple inseminations in a cycle increased the success rate primarily when semen quality was poor. The results of this study show how and to what degree efficacy in A.I.D. can be improved by a judicious choice of the semen to be utilized and the number of inseminations to be practiced.

Adult↗
PubMed1980

Artificial insemination with frozen sperm: protocol, method of analysis and results for 1188 women.

The experience of a sperm bank during a five year period is reported. Artificial insemination by donor (AID) was carried out on 1188 women using frozen sperm prepared in doses of 0.25 ml. A single insemination was called for during each of the first two cycles. The patients were classified in 4 categories: lost to follow-up, successes, dropouts and open cases. The success rate per cycle was about 10 per cent and was very stable for each of the first 12 cycles. The cumulative success rate was calculated by the life table technique adapted for AID analysis. A theoretical success rate (without dropouts) and an effective success rate (with dropouts) were calculated. These two rates were 68 and 55 per cent respectively after 12 cycles. The median delay to conception was 7 and 9 cycles, respectively, under theoretical and effective conditions. The spontaneous abortion rate (17 per cent) and sex-ratio (106 males for 100 females) resemble those for natural reproduction but the success rat per cycle was markedly lower even after adjusting for age.

Adult↗
PubMed1980

[From the cellular pathology of Rudolf Virchow to modern cellular pathology. Results, problems].

Cellular pathology, one of the problems of natural science, is a part of theoretical bases on medicine. Created by R. Virchow in 1855, it has reached a new level, has acquired a new quality particularly in connection with the data obtained in the past 2 decades in investigations of the cell ultrastructure by special methods of electron microscopy. As a result, a hypothesis of diseases associated with organelles has arisen. Currently, mitochondrial and lysosomal diseases are gaining recognition. Examples of them are mitochondrial myopathies and accumulation diseases which can be not only congenital but be induced by lysosomotropic substances. "Organelle pathology" is closely associated with molecular pathology which is the most important basis of "organelle diseases".

Autophagy↗
PubMed1979

A new chromosome anomaly in acute lymphoblastic leukemia (ALL).

A new chromosome anomaly in acute lymphoblastic leukemia (ALL) is reported. Three, possibly four, patients showed an identical karyotype anomaly, characterized by a (4;11)(q13;q22) reciprocal translocation. This anomaly has not so far been found in lymphoproliferative disorders other than ALL. Two of the patients had congenital leukemia, but the anomaly described appears to be more characteristic of ALL than of congenital leukemia, and may help the clinician in establishing the diagnosis of ALL.

Adult↗
PubMed1979

Chromosome abnormalities in acute promyelocytic leukemia (APL).

Sixteen patients, 15 adults and one child, with APL have been studied cytogenetically; 14 of these had an abnormal karyotype (87%). Eleven of these consistently showed a t(15;17)(q26;q22) structural anomaly, one patient showed a 47,+8 karyotype, one a rearrangement of chromosomes No. 15 and No. 17, apparently different from that in the other patients, and one a No. 17 deletion without a demonstrable translocation. as an additional chromosome change trisomy No. 8 was found in 5 cases and monosomy No. 7 in two. The t)15;17)(q26;q22) structural anomaly is highly characteristic of APL, is found in APL of children and adults, but it is apparently not associated with a clinically different form of APL.

Adult↗
PubMed1979

A new characteristic karyotypic anomaly in lymphoproliferative disorders.

A new characteristic chromosome anomaly t(11;14)(q14;q32?) in lymphoproliferative disorders (LPD) is described in 4 cases. The extra material was found on a "14 chromosome (14q+) and belonged to the long arm of one "11 chromosome in 3 cases and to the long arm of a "14 in the other case. These cases confirm that the distal end of chromosome 14q may function as a "receptor site," according to the hypothesis of Kaiser-McCaw et al. and also tend to indicate that chromosome "14 may not be unique in showing so-called "donor" and "receptor sites," and that other chromosomes, in casu chromosome "11, may behave similarly.

Adult↗
PubMed1979

Collagen reduces glycosaminoglycan degradation by cultured mammary epithelial cells: possible mechanism for basal lamina formation.

Collagenous substrates are reported to promote the accumulation of extracellular matrix materials by epithelia in culture. Glycosaminoglycan (GAG) metabolism is compared in secondary cultures of mouse mammary epithelial cells maintained on plastic or type I collagen gel substrates. The incorporation of 35SO42- into GAG during brief labeling indicates no difference between substrates in the rate of GAG synthesis. During prolonged labeling, however, accumulation of [35S]GAG in cultures on colllagen exceeds that of cultures on plastic. This increased accumulation is due to a markedly reduced rate of GAG degradation. GAG degradation does not occur in the medium, indicating that degradation is localized to the cells. The cultures on collagen contain a slowly degrading cell-associated [35S]GAG pool and a ruthenium red-stained basal lamina, neither of which is present in cultures on plastic. The cell-associated [35S]GAG in cultures on collagen is, in part, localized to the site of the ultrastructurally identified basal lamina. Formation of the basal lamina, therefore, may result from collagen-mediated reduction in the degradation of GAG-containing molecules.

Animals↗
PubMed1979

Within-subject variability of human semen in regard to sperm count, volume, total number of spermatozoa and length of abstinence.

The within-subject variability of the semen sperm count (n), volume (v) and the total number of spermatozoa (N) was studied on 220 ejaculates from 36 normal subjects after an abstinence of 7 days or less. For each of the three variables, the within-subject standard deviation, sigma, was practically proportional to the mean, mu; the common value of the coefficient of variation sigma/mu for all subjects was very high: 0.39 for n, 0.28 for v and 0.55 for N. The 95% confidence intervals based on a single ejaculate were asymmetrical and very large, the lower and upper limits being respectively 0.5 x n and 2.3 x n; 0.7 x v and 1.8 x v; 0.4 x N and 2.9 x N. The three semen characteristics for a given subject were highly correlated with length of abstinence: for an increase in abstinence of 1 day there were mean increments of 13 x 10(6)/ml for n, 0.4 ml for v, and 87 x 10(6) for N.

Adult↗
PubMed1979

Male sterility associated with familial translocation heterozygosity: t(8;15) (q22;p11).

During the investigation of the family of a subject consulting for primary sterility, the same oligoteratospermia was found in two of his brothers. The three karyotypes of these subjects exhibited an equilibrated reciprocal autosomal translocation t(8;15) (q22;p11), which was also detected in their mother. The karyotypes of the remaining siblings, one brother and one sister, were normal. The semen analysis of the sterile subjects suggests that the block of gamete production occurs at the beginning of spermiogenesis. The chromosomal anomaly, which has no effect on the reproduction of the mother, leads to sterility of the male offspring bearing it.

Adult↗
PubMed1979

Philadelphia chromosome in human multiple myeloma.

Four patients with multiple myeloma in whom a Ph1 chromosome was found were described; 1 patient had a (9;22) translocation, 2 had no evidence of a translocation, and 1 had a complex translocation (3;8;22). Ph1 chromosomes with standard (9;22) or with unusual translocations were recently found in various myeloproliferative disorders (other than chronic myelogenous leukemia) and in acute lymphoblastic leukemia. These findings point to the genesis of a Ph1 chromosome in diseases other than chronic myelogenous leukemia and other myeloproliferative disorders.

Aged↗