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Biomedical subjects

H Gustafsson

Publications and source records attributed to H Gustafsson.

At least 19 recordsLinked to original sources
PubMed2002

Hormonal measurements in late pregnancy and parturition in dairy cows--possible tools to monitor foetal well being.

Three dairy heifers (A, B and C) were induced to parturition with two prostaglandin (PG) F(2alpha) injections on day 268 and 269 of pregnancy. Signs of approaching parturition were carefully observed. The following parameters were registered: degrees of calving difficulty, date and time of parturition, calf's birth weight and calf's sex. Body temperature was measured and blood samples were taken every 3 h 3 days before the first PGF(2alpha) injection until 3 days after parturition. The plasma concentrations of the PGF(2alpha) metabolite, progesterone, cortisol, oestrone sulphate and pregnancy associated glycoproteins (PAGs) were analysed. Heifers A, B and C delivered 48, 51 and 57 h after the first PGF(2alpha) injection, respectively. Heifer A delivered without any signs of calving difficulty, whereas, the parturition was considered to be slight and moderate difficulty occurred in the delivery of heifers B and C, respectively. The calf of heifer C, without any abnormal gross-evidences, was stillborn. All animals had retained foetal membranes. A slight increase of the PGF(2alpha) metabolite at the time of parturition was found only in heifer C, whereas the levels dramatically increased in all animals 15-24 h after parturition. At the same time, progesterone levels decreased within 3 h after the first PGF(2alpha) injection (P < 0.05) and reached 0.8, 2.7 and 12.4 nmol/l at the time of parturition in heifers A, B and C, respectively. High release of cortisol at the time of parturition was seen in heifer C. Rising levels of oestrone sulphate around the time of parturition were recorded in all heifers, whereas, increasing levels of PAGs were recorded only in heifer A. In conclusion, the patterns of the PGF(2alpha) metabolite, cortisol, progesterone and PAGs were changed in the cases of calving difficulty and stillbirth after PGF(2alpha)-induction of parturition. However, the relationship between oestrone sulphate and PAGs and the status of foetal well being prior to parturition require further elucidation.

Animals↗
PubMed2002

Repeat breeding in dairy heifers: follicular dynamics and estrous cycle characteristics in relation to sexual hormone patterns.

Repeat breeding occurs at an incidence of 10% in the Swedish dairy cow population. Evidence is available for a hormonal asynchrony around estrus in repeat-breeder heifers (RBH). This asynchrony seems to be the underlying cause for a series of dysfunctions such as prolonged standing estrus and delayed ovulation, leading to fertilization failure. For further determinations of repeat-breeder estrous cycle characteristics, seven strictly selected RBH and six virgin heifers (VH) were studied during 3-7 consecutive cycles, with particular attention paid to the estrous period. Follicular dynamics were studied by ultrasonography and related to estrous behavior and pattern of sexual hormones (progesterone, estradiol-17beta, and LH) in peripheral circulation. Mean group data were compared and a classification model was designed. The most prominent findings for RBH were prolonged duration of estrus, delayed LH peak, prolonged lifespan of the preovulatory follicle, and a late postovulatory rise in plasma progesterone. There was also a strong tendency for peri-ovulatory suprabasal progesterone levels in RBH. It is suspected that these deviations cause changes in the microenvironment of the preovulatory follicle, negatively affecting the final maturation of the oocyte. The heterogeneity of the RBH group underlines the multifactorial cause of the repeat-breeder syndrome. The VH formed a homogenous group with data varying within physiological limits. A classification model based on three characteristic variables managed to identify 81% of the VH and 79% of the RBH correctly. Results from this study propose that some heifers have general, consistent problems in synchronizing estrous events, displayed as varying symptoms in the course of consecutive estrous cycles. These subfertile animals could be classified as repeat-breeders.

Animals↗
PubMed2002

Endocrine changes in late bovine pregnancy with special emphasis on fetal well-being.

During late bovine pregnancy, several hormones are involved to maintain and develop a successful result with a live calf. These hormones are e.g., progesterone, high levels during the whole pregnancy period, originating from the corpus luteum, maternal adrenals and placenta. Oestrone sulphate, oestrone in its conjugated form, shows elevated levels from about mid-pregnancy until the third stage of parturition (expelling of the fetal membranes). For the onset of normal parturition and the parturition process as such, a change from progesterone to oestrone synthesis is crucial. The increasing levels of oestrone are time-related to an increased synthesis of prostaglandin F(2alpha) (reflected as elevated levels of 15-ketodihydro-PGF(2alpha)) causing prepartal luteolysis and several hormones are then involved in the labour process such as prostaglandin F(2alpha), cortisol and oxytocin. Cortisol might also be an indicator of stressful events for the dam. Levels of pregnancy associated glycoproteins (PAGs), originating from the trophoblastic binucleate cells, are increasing during the last 10 days prior to parturition. All the mentioned hormones have certain functions during pregnancy, more or less understood. However, could deviations from the expected profiles during late bovine pregnancy indicate impaired fetal well-being or be of importance for reproductive performance during the postpartum period? Abortions, stillbirths or dystocia are situations where endocrine profiles might predict the status of the calf. There are two possible approaches to study the endocrine changes in late pregnancy-to follow spontaneous cases of normal or impaired pregnancies or to experimentally disturb the gestation or induce parturition. We have in one study followed pregnant animals to depict reproductive disturbances, both animals with expected normal parturitions and animals where the sire of the calf has given rise to a high incidence of stillborn calves. The number of stillborn calves or dystocia has been small and so far it has not been possible to obtain a clear picture of the usefulness of endocrine parameters to follow fetal well being, but some of the hormonal parameters show a deviating profile. In a small group of animals with induced parturition (PGF(2alpha)), two out of three had parturition problems and one of these animals had a stillborn calf. All three animals had retained fetal membranes. It was possible to demonstrate a deviating endocrine profile in the cow having the stillborn calf in the sense of higher levels of progesterone, cortisol and 15-ketodihydro-PGF(2alpha) at the time of parturition. In both animals with dystocia the levels of oestrone sulphate after parturition were more sustained. Increasing and high levels of PAGs were only demonstrated in the animal with a normal parturition. These studies are ongoing, aiming at finding changes in endocrine profiles related to impaired pregnancies.

Animals↗
PubMed2002

Cell kinetic changes in human squamous cell carcinomas during radiotherapy studied using the in vivo administration of two halogenated pyrimidines.

The aim of this study was to investigate cell cycle changes during radiation treatment and establish whether treatment intervention could be considered if these changes helped to predict outcome. 33 patients with head and neck cancer were administered iododeoxyuridine (IdUrd) prior to treatment and a second administration of bromodeoxyuridine (BrdUrd) prior to the fifth fraction of 2 Gy. Biopsies were taken several hours after each injection and flow cytometry was used to calculate changes in the cellular kinetics and cell cycle delay in vivo. The kinetic response of the tumour cells was variable; some showed an increase in proliferation during the first week of treatment, whilst the majority showed an inhibition of proliferation. Reduction in the labelling index (LI) and the pretreatment DNA ploidy status and not delays in G2 were the only parameters to correlate with clinical outcome. A lack of reduction in the LI after 1 week of radiotherapy and DNA aneuploidy predicted a group of patients where radiotherapy failed. This information could be helpful in planning future treatment interventions.

Bromodeoxyuridine↗
PubMed2002

New materials for ESR dosimetry.

New materials for electron spin resonance (ESR) dosimetry have been investigated with the aim to find systems more sensitive than L-alanine accepted as a standard for high dose determinations. Among the investigated systems ammonium tartrate, 2-methylalanine, salts of formic acids and dithionates have been found to be more sensitive than alanine by a factor 2-10. The lower limit applies to tissue equivalent materials, while much higher sensitivities were obtained with formates and dithionates containing heavier atoms. The increased sensitivity was mainly attributed to suitable ESR properties of the room temperature stable radicals as regards spectral shape (narrow lines, little or no hyperfine structure) and microwave saturation properties (short relaxation times). The radical structures have when necessary been clarified by ENDOR spectroscopy, while the saturation properties have been screened by pulsed ESR measurements.

Alanine↗
PubMed2002

15-Ketodihydro-PGF(2 alpha), progesterone and uterine involution in primiparous cows with induced retained placenta and post-partal endometritis treated with oxytetracycline and flunixin.

Retention of the foetal membranes (RFM) and post-partal endometritis are common problems in dairy cows. Among other things, the disease is characterized by a bacterial endometritis with aerobic as well as anaerobic bacteria. From an endocrine perspective, cows with RFM have high levels of 15-ketodihydro-PGF(2 alpha) (PG-metabolite) immediately after parturition but these levels fall rapidly within 2 weeks post-partum (early PG-metabolite elevation). After this decline, the PG-metabolite levels increase again and the levels (at this time of a lower magnitude) remain elevated during the period of uterine infection (late PG-metabolite elevation). The aim of this study was to investigate the PG-metabolite profiles in cows with retained placenta and post-partal endometritis treated with the prostaglandin synthesis inhibitor flunixin (F), either alone or in combination with oxytetracycline (T). The study was accomplished over 2 years with 12 primiparous cows in each experiment. As a model for RFM, preterm parturition was induced in late-pregnant heifers by injecting PGF(2 alpha) (25 mg i.m) twice with a 24 h interval. In each experiment, the cows were divided into four groups and treated with either T (10 mg/kg b.w. i.m. once daily), F (2.2 mg/kg b.w. p.o. twice per day), a combination of T and F (dosage, as above), or conservatively (0). The treatment periods lasted from day 11 to day 14 post-partum (pp) in experiment 1 (after placental shedding, groups T1, F1, TF1 and 0) and from day 3 to day 6 pp in experiment 2 (before placental shedding, groups T2, F2, TF2 and 0). Jugular vein blood samples were collected for analyses of PG-metabolite and flunixin. Uterine biopsies were collected twice weekly for investigation of endometrial microbiology. Rectal palpation and ultrasonographic examinations were performed three times per week for investigations of uterine and cervical involution and ovarian activity. No attempts were made to remove the placentas manually. The experiment lasted until day 56 pp. The induction of parturition was successful in all heifers and 22 of 24 animals had RFM. All RFM cows had bacterial endometritis, based on bacteriological examinations. Flunixin treatment (F1, TF1, F2 and TF2) suppressed PG-metabolite levels significantly (p=0.006) during the period of treatment in both experiments. However, the early flunixin treatment only suppressed PG synthesis partially. Late oxytetracycline treatment (T1) did not influence the PG-metabolite levels but oxytetracycline treatment (T2 and TF2) before placental shedding significantly altered the kinetics of the early PG-metabolite elevation compared with other treatments. Late PG-metabolite elevation was significantly correlated to duration of uterine infection and cervical involution. In conclusion, flunixin treatment of cows with retained placenta either before or after placental shedding suppresses prostaglandin synthesis. However, early treatment, when the release of prostaglandins is high, might need more intensive treatment in order to prevent the PG synthesis effectively. Oxytetracycline treatment during the period immediately after parturition before placental shedding might influence the PG-metabolite profile and suggests a bacteriological contribution to the high levels of PG-metabolite seen during the first 2 weeks pp in cows with retained placenta. In this study, a correlation between prostaglandin release, the final cervical involution and the end of infection was found. This suggests a link between uterine endocrinology, bacteriology and involution in cows with retained placenta.

Animals↗
PubMed2002

Insemination of susceptible heifers with semen from a non-viraemic bull with persistent bovine virus diarrhoea virus infection localized in the testes.

Bulls shedding bovine viral diarrhoea virus (BVDV) in semen and simultaneously having a high concentration of circulating antibodies may cause reproductive problems and spread the viral infection within cattle populations. To investigate this in detail, three heifers were inseminated with BVDV-infected semen from a non-viraemic, seropositive Holstein-Friesian bull, named 'Cumulus'. One control heifer was inseminated with semen from a healthy bull that was free of BVDV. All four heifers remained clinically healthy throughout the experiment. The conception succeeded in the control animal and in two of the three heifers inseminated with semen containing BVDV. The heifer with the failed conception was the only one that became systemically infected with BVDV. This animal was deemed non-pregnant by ultrasonic examination on day 34 after insemination and showed no signs of subsequent oestrus during the entire experimental period. At slaughter, 42 days after insemination, there were no histopathological changes in the ovaries and virus was not detected in ovarian tissue. The fact that seronegative dams served with semen from persistently infected bulls have occasionally produced persistently infected calves together with the present findings and the fact that non-viraemic, seropositive bulls can constantly shed BVDV, suggest that the use of semen from such bulls in BVDV-free herds could have far-reaching consequences, especially if it led to the birth of persistently infected (P1) calves.

Animals↗
PubMed2002

Characterisation of the repeat breeding syndrome in Swedish dairy cattle.

Repeat breeding (RB), defined as cows failure to conceive from 3 or more regularly spaced services in the absence of detectable abnormalities, is a costly problem for the dairy producer. To elucidate the occurrence of RB in Swedish dairy herds and to identify risk factors of the syndrome totally 57,616 dairy cows in 1,541 herds were investigated based on data from the official Swedish production-, AI- and disease-recording schemes. The characteristics of the RB syndrome were studied on both herd and individual cow level. The effects of risk factors on the herd frequency of RB were studied by logistic regression. A generalised linear mixed model with logit link, and accounting for herd-level variation by including a random effect of herd, was used to study the individual animal risk for RB. The total percentage of RB animals was 10.1% and the median proportion of RB animals in the herds studied was 7.5%. The proportion of RB cows in herds increased with decreased herd sizes with decreased average days from calving to first AI, with increased herd incidence of clinical mastitis, with decreased reproductive disorders, and increased other diseases treated by a veterinarian. On animal level, the risk factors were milk yield, lactation number, difficult calving or dystocia, season at first service, days in milk at first service and veterinary treatment for reproductive disorders before the first service. Cows being an RB animal in the previous lactation had a higher risk of becoming an RB animal also in the present lactation. In conclusion our results show that the repeat breeding syndrome is a multifactorial problem involving a number of extrinsic factors as well as intrinsic factors coupled to the individual animal.

Animals↗
PubMed2001

Insulin-like growth factor type 1 upregulates uncoupling protein 3.

In this study the expression of uncoupling protein 3 (UCP3) and its regulation by insulin-like growth factor 1 (IGF-I) and insulin in human neuroblastoma SH-SY5Y cells were characterized. Reverse transcriptase-PCR, Western blot, and immunofluorescence analysis showed that SH-SY5Y cells express UCP3 natively. IGF-I induced a time- and concentration-dependent induction of UCP3 protein reaching a twofold expression after 72 h with 10 nM IGF-I. Extremely high insulin concentrations (860 nM) and 10 nM trIGF-I, a truncated form of IGF-I with the same affinity for the IGF-I receptor as the full-length IGF-I, but with lower activity on the insulin receptor, also upregulated UCP3. We conclude that SH-SY5Y cells express UCP3 natively and that the expression is regulated by IGF-I via the IGF-I receptor.

Carrier Proteins↗
PubMed2001

Changes in spinal cholecystokinin release after peripheral axotomy.

The gene expression of cholecystokinin (CCK), a neuropeptide with anti-opioid properties, has been reported to be upregulated in some primary sensory neurons after a peripheral nerve lesion. We have recently demonstrated that the upregulation of CCK mRNA is not accompanied by an increased potassium-evoked release CCK-like immunoreactivity (CCK-LI) 2-4 weeks after a complete transection of the sciatic nerve. The potassium-evoked release of CCK-LI at earlier and later time points has, however, not been studied. The aim of the present in vivo microdialysis study was to monitor how the basal and stimulated extracellular level of CCK in the dorsal horn of the spinal cord is affected at various time points after a complete transection of the sciatic nerve (axotomy). During the first week after transection of the sciatic nerve a tendency towards an elevation of the potassium-induced (100 mM in the perfusion fluid) release of spinal CCK-LI was observed. In contrast, no potassium-induced release of CCK-LI could be detected 2-3 weeks and 2 months after axotomy. No significant effect was observed on the basal extracellular levels of CCK-LI in the dorsal horn. The present study provides further support for the notion that the adaptive changes in the dorsal horn 2 weeks and later after a deafferentiation injury do not include an increased release of CCK.

Animals↗
PubMed2001

Involvement of spinal N-methyl-D-aspartate receptors in capsaicin-induced in vivo release of substance P in the rat dorsal horn.

The aim of the present in vivo microdialysis study was to determine the possible contribution of N-methyl-D-aspartate (NMDA) or alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainate (KA) receptors to capsaicin-induced release of substance P-like immunoreactivity (SP-LI) in the dorsal horn of the rat. Perfusion of a microdialysis probe with capsaicin (50 or 100 microM) induced a significant eight-fold increase of the extracellular SP-LI level. The capsaicin (50 microM)-evoked release of SP-LI was blocked by spinal administration of the NMDA antagonist 2-amino-5-phosphonopentanoic acid (D-APV; 5 mM), but not by the AMPA/KA antagonist 6-nitro-7-sulphamoylbenzo[f]quinoxaline-2,3-dione disodium (NBQX; 0.5 mM). In contrast, the SP-LI release induced by 100 microM capsaicin could not be prevented by D-APV (10 mM) or NBQX (0.5 mM). The data suggest that the spinal SP-LI release induced by a moderate concentration of capsaicin is in part dependent on the release of glutamate acting on NMDA receptors.

2-Amino-5-phosphonovalerate↗
PubMed2001

Clinical and bacteriological aspects on the use of oxytetracycline and flunixin in primiparous cows with induced retained placenta and post-partal endometritis.

Retention of the fetal membranes and post-partal endometritis (RFM) are common problems in dairy cows. Treatment often includes manual removal of the placenta in combination with antibiotic treatment. Earlier studies have shown that cows with endometritis post-partum have a strong tendency to recover spontaneously. The present study focused on treatments of post-partal endometritis with the prostaglandin synthesis inhibitor, flunixin (F) either alone or combined with oxytetracycline (T). The study was conducted in two experiments, using 12 primiparous cows in each. As a model for RFM, premature parturition was induced in late pregnant heifers by injecting PGF2alpha (25 mg i.m.) twice with a 24 h interval. In each experiment the cows were set into four groups and treated with either T (10 mg/kg BW i.m. once daily), F (2.2 mg/kg BW p.o. twice daily), a combination of T and F (dosage, as above) or conservatively (group 0, no drugs). The treatment periods lasted from days 11-14 post-partum in experiment I (groups T1, F1, TF1 and 0) and from days 3-6 post-partum in experiment 2 (groups T2, F2, TF2 and 0). Jugular vein blood samples were collected for analyses of flunixin and total white blood cells. Uterine biopsies were collected twice weekly for investigation of endometrial microbiology. Rectal palpation and ultrasonographic examinations were performed three times weekly for investigations of uterine involution and ovarian activity. No attempts were made to remove the placentas manually. The experiment lasted until day 56 post-partum. The induction of parturition was successful in all heifers and 22 of 24 animals had RFM. All RFM cows had bacterial endometritis. The predominant bacteria were Escherichia coli alpha-haemolytic streptococci, Fusobacterium necrophorum, Arcanobacterium (Actinomyces) pyogenes, Bacteroides spp., Pasteurella spp. and Proteus spp. Fusobacterium necrophorum and A. pyogenes could be isolated for 3-5 weeks post-partum and E. coli Pasteurella and Proteus could be isolated for 2-3 weeks post-partum. Animals treated with tetracycline after placental shedding (T1 and TF1) had a more rapid recovery from infections with A. pyogenes and F. necrophorum than animals that were not treated with tetracycline. No other genera were affected. Antibiotic treatment before placental shedding (T2 and TF2) did not shorten the uterine infection but altered the bacterial flora, seen as an overgrowth of Proteus spp. (p < 0.05) and increased frequency of Pasteurella (p < 0.05). The alpha-haemolytic streptococci were less common in T2 and TF2 than in other groups (NS). Antibiotic treatment of cows before placental shedding (T2 or TF2, n = 6) postponed detachment of placenta compared to cows were no antibiotics were administered before placental shedding (T1, TF1, F1, F2 and 0, n = 16. 9.8 days pp (median) versus p = 0.004). Neither treatment shortened uterine involution. Flunixin treatments did not seem to influence recovery from infection or uterine involution. It was concluded that early oxytetracycline treatment of retained fetal membranes in the cow did not shorten the uterine involution or uterine infection but it did slow down the detachment process of the retained placenta. Oxytetracycline treatment after placental shedding might shorten the uterine infection but otherwise did not affect the clinical results. Flunixin treatment had no influence on the clinical outcome of the disease.

Administration, Oral↗
PubMed2001

Morphine-induced in vivo release of spinal cholecystokinin is mediated by delta-opioid receptors--effect of peripheral axotomy.

Morphine and other opioid agonists induce spinal in vivo release of cholecystokinin (CCK), a neuropeptide with anti-opioid properties. However, so far the opioid receptor subtype responsible for this effect has not been determined. In the present in vivo microdialysis study, the morphine-induced release of cholecystokinin-like immunoreactivity (CCK-LI) in the dorsal horn was completely blocked by the delta-opioid antagonist naltrindole (10 microM in the perfusion fluid). Neither the mu-opioid receptor antagonist D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr amide (CTOP; 10 microM in the perfusion fluid), nor the kappa-opioid receptor antagonist nor-binaltorphimine (nor-BNI); 10 microM in the perfusion fluid) had any significant effect in this respect. In addition, systemic administration of the delta-opioid receptor agonist BW373U86 (1 mg/kg, s.c.) and spinal administration of the delta(2)-opioid receptor agonist, Tyr-D-Ala-Phe-Glu-Val-Val-Gly amide ([D-Ala(2)] deltorphin II) (1 microM in the perfusion fluid) induced a significant increase of the CCK-LI level. The effect of BW373U86 on spinal CCK-LI release was completely blocked by spinal administration of naltrindole. The mu-opioid receptor agonist [D-ala(2)-N-Me-Phe(4)-Gly(5)-ol]-enkephalin (DAMGO) (1 microM in the perfusion fluid or 1 mg/kg, s.c.) failed to alter the CCK-LI level. Peripheral nerve lesions have previously been shown to down-regulate mu- and delta-opioid receptors in the dorsal horn, to increase the gene-expression of CCK and CCK-receptor mRNA in dorsal root ganglion neurons and to alter the potassium-induced spinal CCK-LI release. After complete sciatic nerve transection, administration of the two selective delta-opioid receptor agonists induced a significant release of CCK-LI, which was comparable to controls. In contrast, neither systemic nor spinal administration of morphine and DAMGO altered the spinal CCK-LI release in axotomized animals. The present data indicate that the delta-opioid receptor mediates morphine-induced CCK-LI release in the spinal cord.

Analgesics, Opioid↗
PubMed2001

15-ketodihydro-PGF2 alpha, progesterone and cortisol profiles in heifers after induction of parturition by injection of dexamethasone.

In order to study rapid changes in 15-ketodihydro-PGF2 alpha, cortisol and progesterone in the period preceding parturition in cattle, pre-term parturition was induced in 4 late pregnant heifers. Parturitions were induced by 2 intramuscular injections of 20 mg dexamethasone with a 24-h interval. The first injection was made on days 254, 258, 264 and 265 in gestation, respectively. Twenty-four h before the first injection an intravenous polyurethane cannula was inserted. Blood samples were collected at least every hour until 12 h after parturition and during the second stage of labour at least 6 times per hour. Plasma was analysed for 15-ketodihydro-PGF2 alpha and progesterone by radioimmunoassays, and for cortisol by an ELISA. The average time from injection to parturition was 7.7 (6.6-8.9) days (mean (range)). Two of the heifers had retained foetal membranes (RFM). At the start of the experiment the levels of PGF2 alpha metabolite were low (< 300 pmol/L) and increased slowly to levels between 1000 and 2000 pmol/L at one day before parturition. During the last day, however, the levels increased rapidly and the highest levels (> 10,000 pmol/L) were reached at the time of delivery. No pulsatile release was seen. Immediately after foetal expulsion the PG-metabolite levels decreased rapidly in all animals. In the 2 animals with RFM, however, this decline ceased within a few h. The PG-metabolite levels in these animals then started to increase and reached levels as high as during parturition. Luteolysis occurred between 1.6 and 0.4 days before parturition in all animals. The cortisol profile showed a distinct peak at the time of parturition in the RFM heifers. This peak was absent in the non-RFM heifers. This study shows that the PGF2 alpha release at prepartal luteolysis and parturition is not pulsatile in cattle and that cortisol profiles in heifers with retained foetal membranes might differ from the profiles in non-RFM heifers at the time of parturition.

Animals↗
PubMed2001

Effect of tetracosactid on post partum cyclicity in cows after induction of parturition with PGF2 alpha.

Parturition and retention of fetal membranes were induced with PGF2 alpha in 3 primiparous dairy cows. Starting on day 12 post partum (PP) the cows were treated with 500 micrograms i.m. of ACTH-analogue (tetracosactid) every 6 h for 6 times. Changes in plasma concentrations of cortisol, progesterone and 15-ketodihydro-PGF2 alpha were evaluated immediately after treatment. The effects on the resumption of ovarian activity were evaluated by clinical and ultrasound examinations and by progesterone and 15-ketodihydro-PGF2 alpha analyses for 56 days after parturition. Treatment was able to induce a statistically significant (p < 0.01) similar increase in cortisol and progesterone after both the 1st and the 6th injections, in all cows. No changes in 15-ketodihydro-PGF2 alpha concentrations were seen after any of the injections of ACTH-analogue. The first corpus luteum (CL) was seen on day 18 PP (cow A), and 28 (cow B) and in both cases it was followed by a normal ovarian cyclicity. No CL was observed during the whole period of study in cow C. Progesterone profiles confirmed these clinical and ultrasonographic findings. The steroid output, especially progesterone, induced by the ACTH-analogue might be a stimulus for the onset of ovarian cyclicity, since 2 of the 3 animals ovulated earlier than expected. These findings point to the fact that interference with the stress system might have a positive effect on ovarian cyclicity. The different pattern of response does however demand further studies.

Animals↗
PubMed2001

Vascular function and blood pressure in GH transgenic mice.

Acromegaly is associated with cardiovascular disease. We studied vascular function and mean arterial blood pressure in transgenic mice overexpressing bovine GH. Mean arterial blood pressure was measured in conscious, unrestrained male and female bovine GH and littermate control mice during normal as well as high salt intake using telemetric devices. Structure in artificially perfused maximally dilated hindquarter vascular beds and vascular reactivity and endothelial function in small mesenteric vessels were studied in female bovine GH and control mice. Mean arterial blood pressure was increased in female bovine GH transgenic (126 +/- 3 mm Hg) and male bovine GH transgenic (129 +/- 4 mm Hg) compared with female (109 +/- 3 mm Hg, P < 0.05) and male (111 +/- 3 mm Hg, P < 0.05) controls respectively. Increased salt intake had no effect on mean arterial blood pressure. Perfusion studies showed a significant decrease in the average diameter of the female bovine GH transgenic hindquarter vascular bed (P < 0.05). The responses of isolated resistance arteries to nor-epinephrine, potassium-induced depolarization, acetylcholine, or sodium-nitroprusside did not significantly differ between bovine GH transgenic and control mice. We conclude that the phenotype of the bovine GH transgenic mice includes a salt-resistant form of hypertension. Furthermore, the increase in mean arterial blood pressure is accompanied by a significant structural narrowing of the resistance vasculature without changes in vascular reactivity or endothelial function. The results imply that hypertension in bovine GH transgenic mice is maintained mainly by a structurally based increase in peripheral vascular resistance.

Animals↗
PubMed2000

Peripheral axotomy increases cholecystokinin release in the rat anterior cingulate cortex.

The anterior cingulate cortex (ACC) is a limbic region with a high density of cholecystokinin (CCK) immunoreactivity, that has been suggested to be of importance for the affective and emotional component of pain. In the present microdialysis study, performed in the awake rat, we demonstrate a bilateral 4- to 6-fold increase of the potassium-induced release of CCK-like immunoreactivity (CCK-LI) in the ACC 2-3 weeks after a unilateral transection of the sciatic nerve (axotomy), an animal model of phantom limb or deafferentiation pain. Considering the implication of CCK in pain modulation and anxiety, we suggest that an altered activity of CCK containing neurons in the ACC may be of importance for the affective component of certain pain conditions.

Animals↗