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J Jaroszewski

Publications and source records attributed to J Jaroszewski.

48 records · Page 3Linked to original sources
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Involvement of beta-adrenoceptors in the regulation of luteal function in cattle.

The infusion of beta-adrenomimetic drug (bamethan sulphate--BS) on day 11 of the oestrous cycle markedly increased peripheral progesterone concentration whereas infusion of beta-antagonist (propranolol) decreased plasma progesterone levels in heifers. Oxytocin injected on days 2-6 of the oestrous cycle shortened the length of the cycle (to 7-9 days) whereas the length of the cycle in heifers injected with oxytocin followed by injections of either BS or xanthinol (theophylline nicotinate--a potent vasodilatory drug) was normal (21.8 +/- 1.7). Heifers injected with BS on days 13-21 of the oestrous cycle had increased levels of progesterone on days 13-19 of the cycle and the length of the cycle was normal (22.3 +/- 0.6 compared with 21.3 +/- 1.5 for the control). The data indicate that: (1) beta-adrenergic stimulation overcomes the action of oxytocin given on days 2-6 of the cycle, whereas the stimulation of beta-receptors on days 13-21 of the oestrous cycle raised progesterone plasma concentration but did not prevent spontaneous luteolysis. (2) Basal secretion of progesterone in cattle is partly dependent on constant beta-adrenergic stimulation.

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Articular cartilage repair by means of biodegradable scaffolds.

INTRODUCTION: Articular cartilage has a limited capacity for self-repair; untreated injuries of cartilage may lead to osteoarthritis. In severe cases the only choice a total joint replacement, may be inadequate in young patients. This problem demands new effective methods to reconstruct articular cartilage. The aim of this study was to evaluate the application of collagen matrix for the reconstruction of articular cartilage. MATERIALS AND METHODS: A group of 28 rabbits had a defect penetrating into the subchondral constructed and either filled with collagen scaffold (group I) or remained empty (group II). The results were observed after 4 and 12 weeks. Macroscopic and microscopic evaluations were performed. RESULTS: In the first group we observed the presence of hyalinelike cartilage resembling normal articular cartilage. In the second group fibrous tissue dominated. The surface of regenerated tissue was smooth, intact, and the defect completely filled with regenerated tissue, showing good structural integrity. In the second group, superficial irregularities, disorders of structural integrity, and necrotic features were noticed. CONCLUSIONS: This study showed better results of articular cartilage reconstruction by means of a biodegradable scaffold.

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Evaluation of cartilage reconstruction by means of autologous chondrocyte versus periosteal graft transplantation: an animal study.

BACKGROUND: Autologous chondrocyte transplantation (ACT) has been shown to heal cartilage defects under experimental and clinical conditions. However, the evaluation of successful transplantation still remains arbitrary and further research is required to establish objective criteria of treatment. The aim of the present study was to evaluate the criteria of successful ACT and to compare the results with those obtained following periosteal grafting (PG). MATERIALS AND METHODS: Articular cartilage specimens were taken from the distal femur of 30 adolescent New Zealand rabbits and chondrocytes were obtained by collagenase digestion. The chondrocytes were identified by a functional assay, based on estimating procollagen type II mRNA by reverse-transcribed polymerase chain reaction. The cells cultured in vitro were transplanted under a periosteal flap into a full thickness defect (ICRS III(0)). The quality of the repaired tissue was evaluated macroscopically according to a modified scale of Brittberg et al, and microscopically according to O'Driscoll et al. For comparative purposes animals treated with PG were used. RESULTS: Cultured chondrocytes expressed procollagen type II and, upon transplantation into the defect, produced hyaline cartilage. To evaluate the results of transplantation, two categories of criteria were adopted-macroscopic analysis and microscopic examination. By all adopted criteria the results were significantly better in the ACT group (P < .05) than in the PG group. CONCLUSION: Prior to transplantation, assays for specialized functions of chondrocytes required semiquantitative evaluation of macroscopic and microscopic appearance of the repaired tissue, showing the benefit of autologous chondrocyte versus periosteal graft transplantation.

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PubMedDate not supplied

Uterine secretion of prostaglandin F2alpha stimulated by different doses of oxytocin and released spontaneously during luteolysis in cattle.

The objectives were to determine the involvement of oxytocin (OT) in the stimulation of prostaglandin F2alpha (PGF) secretion during luteolysis in cattle. On days 16-17 of the oestrous cycle, catheters were inserted into the aorta abdominalis of heifers for OT or saline infusion and into the jugular vein for blood sample collection. The following day, heifers were assigned to one of three experimental groups (Gr): Gr I - 10 IU OT (n=4); Gr II - 20 IU OT (n=4); Gr III - 50 IU OT (n=4). Blood samples were collected every 10 min during a 1-h control period before treatment and every 5-10 min for 2 h after OT treatment. In Gr IV (n=5), a catheter was inserted into the jugular vein on day 15 of the cycle and blood samples were collected every 15 min for 12 h on days 16-19. Plasma concentrations of progesterone, PGF metabolite, 13, 14-dihydro-15-keto-prostaglandin F2alpha (PGFM) and OT were determined. Within 5 min of infusion of 10 or 20 IU OT, peripheral concentrations of OT (7-12 pg/mL) increased by about 200 and 350-500 pg/mL, respectively. These doses did not affect plasma concentrations of PGFM or progesterone within 1.5 h. Fifty IU of OT increased its maximal peripheral concentration to 1500 pg/mL, which is over 20 times greater than that observed physiologically. Concentrations of plasma PGFM in Gr III increased from basal concentrations (5065 pg/mL) to 150-250 pg/mL (P < 0.01) within 10-30 min. During luteolysis, PGFM pulses ranged between 250 and 600 pg/mL on days 16-19 of the cycle (Gr IV), whereas coincident pulses of OT, and those appearing between spikes of PGFM, were never above 75 pg/mL. Only 50% of OT pulses coincided with pulses of PGFM, and 54 % of PGFM pulses coincided with a pulse of OT. Results indicate that luteolytic PGF secretion in cattle is not directly dependent upon ovarian OT.

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