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Biomedical subjects

H J Voss

Publications and source records attributed to H J Voss.

At least 19 recordsLinked to original sources
PubMed2003

[Integration of periosteum covered autogenous bone grafts with and without autologous chondrocytes. An animal experiment using the Göttinger minipig].

Autologous osteochondral transplantation has the major disadvantage of significant damage to a healthy joint surface at the donor site. The purpose of this study was to examine the effect of autogenous chondrocytes injected into the periosteum of autologous bone grafts in order to provide an alternative method for cartilage repair. A total of 22 Göttinger minipigs were operated twice on both knees. The first operation served for cartilage biopsy for the chondrocyte culture. During the second operation an osteochondral defect was created in the medial facet of the trochlear groove. The defect was treated differently with an autologous cortico-cancellous bone cylinder,harvested from the proximal tibia.Group A: untreated defect (control);B: bone-graft;C: bone-graft covered with periosteum; D: bone-graft with periosteum and injected autologous chondrocytes. The animals were killed after 6, 12, 26 and 52 weeks. The regenerated areas were evaluated macroscopically, tested biomechanically (long-term specimens; indentation-test) and a histological, blind evaluation was carried out according to a semi-quantitative scoring system. The periosteum covered bone cylinders in Groups C and D showed good repair of the bone and cartilage defect. The repaired tissue consisted predominantly of fibrocartilage with the partial formation of hyalin like tissue. The regenerated areas were integrated with the adjacent cartilage and were biomechanically superior when compared with the other groups. The additional injection of chondrocytes did not produce significantly better results. Our findings suggest that the transplantation of periosteum-covered bone cylinders may provide an alternative method for treating chondral and osteochondral defects and can be recommended for filling large donor site defects in joint surgery. The additional transplantation of chondrocytes does not seem to be justified.

Animals↗
PubMed1989

Buserelin in a superovulatory regimen for Holstein cows. I. Pituitary and ovarian hormone response in an experimental herd.

Two experiments were conducted with frequent blood sampling in standard superovulatory regimens using follicle stimulating hormone (FSH) and prostaglandin F(2) alpha (PGF) to study the effects of the gonadotropin releasing hormone analog, Buserelin, on changes in FSH, luteinizing hormone (LH), progesterone (P(4)) and estradiol (E(2)). In Experiment I, Buserelin (20 mug) was administered to a total of 28 dry Holsteins. One group was treated with Buserelin 36 and 60 h after PGF administration, a second group was treated 60 h after PGF, and a third group served as the controls. In Experiment II, 30 dry Holsteins received Buserelin (10 mug). One group was treated 48 h after PGF, a second group at 54 h after PGF, a third group 24 h after estrus was first observed and a fourth group was a control. The general pattern of a decrease in P(4) following PGF, an increase in E(2), the onset of estrus, an LH peak, and finally, an increase in P(4) in superovulated cows was observed. Buserelin consistently produced a sharp LH peak at 36 h when given 36 h after PGF. At later intervals, it produced either a major or minor peak depending upon whether a spontaneous LH peak had already occurred. There was too much individual cow variation in the interval from PGF to a spontaneous LH peak to consistently induce a uniform LH peak, except when Buserelin was given 36 h after PGF, which may be early for normal oocyte maturation. There was no treatment effect on FSH, and embryo recovery rate was unaffected by treatment (P>0.05).

Journal Article↗
PubMed1985

Controlling estrus in dairy cows - A comparative field study.

Two prostaglandins, Estrumate and Dinolytic, and two progestagens, PRID and Norgestomet were compared for their effectiveness in controlling estrus in dairy cows. A total of 636 animals on 62 different farms in southern Lower Saxony/FRG were used in this study. After treatment with one of the four drugs a double fixed time insemination was always performed at 24-hour intervals. Later, an additional untreated animal was assigned to each group of four. The conception rate in the 734 cows which were inseminated and evaluated under standardized experimental conditions were ES, 51.0%; DY, 46.0%; PRID, 44.5%; NOR, 34.7% and untreated animals, 46.9%. When only those cows which had already calved were considered, the rates were 48.0%, 44.6%, 46.9%, 31.9% and 59.1% respectively. The time of treatment post-partum proved to be significant for the non-return rate 90 (P < 0.01) and the conception rate (P < 0.05). Treatment influenced the estrus cycle in all of the cows. Abnormal cycle length following treatment was observed in 50.7%, 52.0%, 41.6% and 52.8% of the cows in each group as compared to 12.1% in the untreated animals. After the third insemination at least 90% of the cows in each group had conceived. The effect of the various farms proved to be significant with regard to the insemination index (P < 0.01), NRR 90 (P < 0.05) and the conception rate (P < 0.05). All four drugs established their suitability for use under field conditions. Still, modifications in the treatment methods and the insemination regimen could lead to higher fertilization rates.

Journal Article↗
PubMed1984

Recovery rate and quality of embryos collected from suckled cows and beef heifers after superovulation with PMSG.

Recovery rate and embryo quality were investigated in beef heifers and suckled cows following superovulation induced by 2000 IU pregnant mare serum (PMSG) combined with different methods of estrus cycle synchronization (Norgestomet, Prid, Dinolytic, Norgestomet combined with Dinolytic). Genital tracts were flushed upon slaughter with Dulbecco's medium 6.5 to 7.5 days after insemination. Of the heifers, 42 out of 43 responded to treatment. The mean embryo recovery rate, based on the number of corpora lutea, was only 14.8%. Of the 83 embryos recovered, 54.2% had developed to the expected stage and only 40% appeared normal. Of the adult cows, 55 out 58 responded with an embryo recovery rate of 39.5%. Of the 149 embryos recovered, 48.9% had developed to the expected stage and 67.1% of these appeared normal. In both heifers and adult cows, the different methods of estrus synchronization produced no significant differences in recovery rate or embryo quality.

Journal Article↗
PubMed1979

Estrus synchronization and superovulation with a subcutaneous gestagen implant (Norgestomet, Intervet) in suckler cows and heifers.

Four trials were conducted to investigate the suitability of a gestagen implant (Norgestomet, Intervet) for estrus synchronization and superovulation in suckler cows and heifers kept under field conditions in Germany. In trial 1 out of 17 heifers treated 12 responded with one ovulation each. In trial 2 57 suckler cows were treated at the University experimental farm. Of 23 cows treated sooner and 34 cows treated later than 50 days post partum one (4 %) and 16 (47 %) respectively calved at the expected time. Trial 3 was a field trial involving 126 suckler cows and 21 heifers. Of 24 cows treated sooner and 102 cows treated later than 50 days post partum 17 % and 52 % respectively calved at the expected time. Of the 21 heifers only 19 % calved at the expected time. In trial 4 superovulation of 13 cows and 17 heifers resulted in 62 % and 94 % responding with 10.0 +/- 2.5 and 11.1 +/- 3.0 (x +/- SD ) ovulations per animal respectively.

Journal Article↗