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Biomedical subjects

N Dourov

Publications and source records attributed to N Dourov.

At least 73 records · Page 4Linked to original sources
PubMed1986

The effect of orchidectomy on bone metabolism in aging rats.

We have shown that orchidectomy in postpubertal 55-day-old rats led beyond 2 months to a decrease in bone growth and loss of weight. At 1 month postorchidectomy, we observed a three-fold increase in bone blood flow, an increase in calcium accretion rate, and an increase in the number of osteoclasts in the metaphysis. In the present experimental study, orchidectomy was performed in 1-year-old rats when bone growth in length was no longer measurable. In the tibia and femur we observed a decrease in bone volume, a still more rapid decrease of bone calcium during the first postoperative month, a thinning of the cortical width, an initial increase in calcium accretion rate (+20% when compared to 31 days controls) followed by a decrease at 120 days (-22% and -11% when compared to controls for tibia and femur respectively), a 29% increase in bone blood flow, and an increase in the number of osteoclasts. We conclude that androgen deprivation in young and old animals leads to a modified bone architecture, independent of the androgen impact on bone growth.

Animals↗
PubMed1984

Growth and bone haemodynamic responses to castration in male rats. Reversibility by testosterone.

Orchidectomy in postpubertal 55 day old rats, compared to sham-operated controls, led beyond 2 months to a decrease in body weight (87% of controls by 120 d), tibial length (97% of controls) and in tibial calcium content (85% of controls). Bone plasma flow increased three times to reach a peak at 31 days; it was decreased but no significantly at 86 and 120 days. The number of osteoclasts was maximal at 51 days (X 2.3) and was still elevated at 120 days. The calcium accretion rate increased briefly at 31 days (110% of controls) and was diminished at 86 and 120 days (78% of controls). The initial 'physiological' changes in the tibia occurred before any weight change and might be directly due to the lack of androgens. They can be interpreted as inducing the conditions for enhanced bone resorption. Testosterone replacement therapy, initiated after the initial haemodynamic response, inhibited the negative effect of castration on bone growth.

Age Factors↗
PubMed1984

Scanning electron microscopy contribution in oral pathology.

The comparative study by optical and scanning electron microscopy provides useful information in oral pathology. Four aspects of the superficial cell surface of the lip and the gingival and lingual mucosa can be described: 1. parallel microridges; 2. honeycomb appearance; 3. microvilli; 4. a more or less smooth surface. This 4th type is often encountered in cases of leukoplakia and in carcinomas. The variable morphology of the epithelial surface may be related to cells modifications during maturation. In hairy tongue conditions, the filiform papillae are enlarged by cellular conglomerates and by apposition of bacteria and pseudohyphae, while in a case of sclerodermia they were no more visible.

Humans↗