The Feasibility of High-Resolution Peripheral Quantitative Computed Tomography (HR-pQCT) in Patients with Suspected Scaphoid Fractures.

INTRODUCTION: Diagnosing scaphoid fractures remains challenging. High-resolution peripheral quantitative computed tomography (HR-pQCT) might be a potential imaging technique, but no data are available on its feasibility to scan the scaphoid bone in vivo. METHODOLOGY: Patients (≥18 years) with a clinically suspected scaphoid fracture received an HR-pQCT scan of the scaphoid bone (three 10.2-mm stacks, 61-µm voxel size) with their wrist immobilized with a cast. Scan quality assessment and bone contouring were performed using methods originally developed for HR-pQCT scans of radius and tibia. The contouring algorithm was applied on coarse hand-drawn pre-contours of the scaphoid bone, and the resulting contours (AUTO) were manually corrected (sAUTO) when visually deviating from bone margins. Standard morphologic analyses were performed on the AUTO- and sAUTO-contoured bones. RESULTS: Ninety-one patients were scanned. Two out of the first five scans were repeated due to poor scan quality (40%) based on standard quality assessment during scanning, which decreased to three out of the next 86 scans (3.5%) when using an additional thumb cast. Nevertheless, after excluding one scan with an incompletely scanned scaphoid bone, post hoc grading revealed a poor quality in 14.9% of the stacks and 32.9% of the scans in the remaining 85 patients. After excluding two scans with contouring problems due to scan quality, bone indices obtained by AUTO- and sAUTO-contouring were compared in 83 scans. All AUTO-contours were manually corrected, resulting in significant but small differences in densitometric and trabecular indices (<1.0%). CONCLUSIONS: In vivo HR-pQCT scanning of the scaphoid bone is feasible in patients with a clinically suspected scaphoid fracture when using a cast with thumb part. The proportion of poor-quality stacks is similar to radius scans, and AUTO-contouring appears appropriate in good- and poor-quality scans . Thus, HR-pQCT may be promising for diagnosis of and microarchitectural evaluations in suspected scaphoid fractures.

Validation of distal radius failure load predictions by homogenized- and micro-finite element analyses based on second-generation high-resolution peripheral quantitative CT images.

This study developed a well-standardized and reproducible approach for micro-finite element (mFE) and homogenized-FE (hFE) analyses that can accurately predict the distal radius failure load using either mFE or hFE models when using the approaches and parameters developed in this study. INTRODUCTION: Micro-FE analyses based on high-resolution peripheral quantitative CT (HR-pQCT) images are frequently used to predict distal radius failure load. With the introduction of a second-generation HR-pQCT device, however, the default modelling approach no longer provides accurate results. The aim of this study was to develop a well-standardized and reproducible approach for mFE and hFE analyses that can provide precise and accurate results for distal radius failure load predictions based on second-generation HR-pQCT images. METHODS: Second-generation HR-pQCT was used to scan the distal 20-mm section of 22 cadaver radii. The sections were excised and mechanically tested afterwards. For these sections, mFE and hFE models were made that were used to identify required material parameters by comparing predicted and measured results. Using these parameters, the models were cropped to represent the 10-mm region recommended for clinical studies to test their performance for failure load prediction. RESULTS: After identification of material parameters, the measured failure load of the 20-mm segments was in good agreement with the results of mFE models (R2 = 0.969, slope = 1.035) and hFE models (R2 = 0.966, slope = 0.890). When the models were restricted to the clinical region, mFE still accurately predicted the measured failure load (R2 = 0.955, slope = 1.021), while hFE predictions were precise but tended to overpredict the failure load (R2 = 0.952, slope = 0.780). CONCLUSIONS: It was concluded that it is possible to accurately predict the distal radius failure load using either mFE or hFE models when using the approaches and parameters developed in this study.

Bone microarchitecture and strength assessment in adults with osteogenesis imperfecta using HR-pQCT: normative comparison and challenges.

Data on bone microarchitecture in osteogenesis imperfecta (OI) are scarce. The aim of this cross-sectional study was to assess bone microarchitecture and strength in a large cohort of adults with OI using high-resolution peripheral quantitative computed tomography (HR-pQCT) and to evaluate challenges of using HR-pQCT in this cohort. Second-generation HR-pQCT scans were obtained at the distal radius and tibia in 118 men and women with Sillence OI type I, III, or IV using an extremity-length-dependent scan protocol. In total, 102 radius and 105 tibia scans of sufficient quality could be obtained, of which 11 radius scans (11%) and 14 tibia scans (13%) had a deviated axial scan angle as compared with axial angle data of 13 young women. In the scans without a deviated axial angle and compared with normative HR-pQCT data, Z-scores at the radius for trabecular bone mineral density (BMD), number, and separation were -1.6 ± 1.3, -2.5 ± 1.4, and -2.7 (IQR: 2.7), respectively. They were -1.4 ± 1.5 and -1.1 ± 1.2 for stiffness and failure load and between ±1 for trabecular thickness and cortical bone parameters. Z-scores were significantly lower for total and trabecular BMD, stiffness, failure load, and cortical area and thickness at the tibia. Additionally, local microarchitectural inhomogeneities were observed, most pronounced being trabecular void volumes. In the scans with a deviated axial angle, the proportion of Z-scores <-4 or >4 was significantly higher for trabecular BMD and separation (radius) or most total and trabecular bone parameters (tibia). To conclude, especially trabecular bone microarchitecture and bone strength were impaired in adults with OI. HR-pQCT may be used without challenges in most adults with OI, but approximately 12% of the scans may have a deviated axial angle in OI due to bone deformities or scan positioning limitations. Furthermore, standard HR-pQCT parameters may not always be reliable due to microarchitectural inhomogeneities nor fully reflect all inhomogeneities.

OI is a rare condition with large clinical heterogeneity. One of the major characteristics associated with OI is the increased fracture risk due to defects in bone structure and material. Data on the defects in bone structure at the micrometer level (i.e. bone microarchitecture) are scarce. Bone microarchitecture can be assessed noninvasively using HR-pQCT, but its use in OI has not extensively been described. Yet, potential challenges may arise related to among others the occurrence of short extremities and skeletal deformities in OI. We assessed bone microarchitecture and strength in 118 adults with OI types I, III, or IV using HR-pQCT with an extremity-length-dependent scan protocol. Additionally, we evaluated potential challenges of using HR-pQCT in this cohort. Our results demonstrated that predominantly trabecular microarchitecture­especially trabecular number and separation­and overall bone strength were impaired in adults with OI as compared with normative data. Furthermore, we observed various microarchitectural inhomogeneities, most pronounced being trabecular void volumes. Regarding applicability, HR-pQCT could be used without challenges in most adults with OI. However, deviations in scan region may potentially influence HR-pQCT parameters, and standard HR-pQCT analyses may not always give accurate results due to microarchitectural inhomogeneities nor fully reflect all microarchitectural inhomogeneities.

PPI use is not associated with bone microarchitecture and strength assessed with HR-pQCT after three-years follow-up in patients visiting the Fracture Liaison Service.

BACKGROUND: The use of proton pump inhibitors (PPIs) has been associated with an increased fracture risk in observational studies. However, the reported association between PPI use and bone mineral density (BMD), bone microarchitecture, and bone strength is inconsistent. This study aims to assess the association between PPI use and bone microarchitecture and strength using high-resolution peripheral quantitative CT (HR-pQCT) in a three-year follow-up study in patients with a recent fracture visiting the Fracture Liaison Service (FLS). METHODS: This three-year prospective cohort study included FLS patients aged ≥ 50 years with a recent fracture (median age 62 [IQR 56-69] years, 68.7 % females) and without anti-osteoporosis treatment indication. HR-pQCT scans (distal radius and tibia) were obtained at baseline (T0) and three-year follow-up (T3). Volumetric bone mineral density and bone area, microarchitecture, and strength (micro-finite element analysis) were determined. The association between three-year continuous PPI use and the percentage change in HR-pQCT parameters between T0 and T3 was assessed using sex-stratified multivariate linear regression analyses. Covariates included age, BMI, vitamin-D deficiency (< 50 nmol/l), glucocorticoid use, and cardiovascular co-morbidity (males and females) fracture type (major/hip vs. all others, only males) and probable sarcopenia (only females). RESULTS: In total, 282 participants had available medication data throughout follow-up, of whom 20.6 % were continuous PPI users. In both males and females with complete HR-pQCT follow-up data (males: N = 69 radius, N = 84 tibia; females: N = 147 radius, N = 168 tibia), PPI use was not associated with the percentage change of any of the bone microarchitecture or strength parameters between T0 and T3 at the radius and tibia as compared to non-use. CONCLUSION: Compared to non-use, PPI use was not associated with the change of bone microarchitecture and strength in FLS patients at three years of follow-up. These results do not support that an altered bone microarchitecture or strength may contribute to the increased fracture risk associated with PPI use, as reported in observational studies.

Assessment of the healing of conservatively-treated scaphoid fractures using HR-pQCT.

Improving the clinical outcome of scaphoid fractures may benefit from adequate monitoring of their healing in order to for example identify complications such as scaphoid nonunion at an early stage and to adjust the treatment strategy accordingly. However, quantitative assessment of the healing process is limited with current imaging modalities. In this study, high-resolution peripheral quantitative computed tomography (HR-pQCT) was used for the first time to assess the changes in bone density, microarchitecture, and strength during the healing of conservatively-treated scaphoid fractures. Thirteen patients with a scaphoid fracture (all confirmed on HR-pQCT and eleven on CT) received an HR-pQCT scan at baseline and three, six, twelve, and 26 weeks after first presentation at the emergency department. Bone mineral density (BMD) and trabecular microarchitecture of the scaphoid bone were quantified, and failure load (FL) was estimated using micro-finite element analysis. Longitudinal changes were evaluated with linear mixed-effects models. Data of two patients were excluded due to surgical intervention after the twelve-week follow-up visit. In the eleven fully evaluable patients, the fracture line became more apparent at 3 weeks. At 6 weeks, individual trabeculae at the fracture region became more difficult to identify and distinguish from neighboring trabeculae, and this phenomenon concerned a larger region around the fracture line at 12 weeks. Quantitative assessment showed that BMD and FL were significantly lower than baseline at all follow-up visits with the largest change from baseline at 6 weeks (-13.6% and - 23.7%, respectively). BMD remained unchanged thereafter, while FL increased. Trabecular thickness decreased significantly from baseline at three (-3.9%), six (-6.7%), and twelve (-4.4%) weeks and trabecular number at six (-4.5%), twelve (-7.3%), and 26 (-7.9%) weeks. Trabecular separation was significantly higher than baseline at six (+13.3%), twelve (+19.7%), and 26 (+16.3%) weeks. To conclude, this explorative HR-pQCT study showed a substantial decrease in scaphoid BMD, Tb.Th, and FL during the first 6 weeks of healing of conservatively-treated scaphoid fractures, followed by stabilization or increase in these parameters. At 26 weeks, BMD, trabecular microarchitecture, and FL were not returned to baseline values.

Improved Detection of Scaphoid Fractures with High-Resolution Peripheral Quantitative CT Compared with Conventional CT.

BACKGROUND: Computed tomography (CT), magnetic resonance imaging, and bone scintigraphy are second-line imaging techniques that are frequently used for the evaluation of patients with a clinically suspected scaphoid fracture. However, as a result of varying diagnostic performance results, no true reference standard exists for scaphoid fracture diagnosis. We hypothesized that the use of high-resolution peripheral quantitative CT (HR-pQCT) in patients with a clinically suspected scaphoid fracture could improve scaphoid fracture detection compared with conventional CT in the clinical setting. METHODS: The present study included 91 consecutive patients (≥18 years of age) who presented to the emergency department with a clinically suspected scaphoid fracture between December 2017 and October 2018. All patients were clinically reassessed within 14 days after first presentation, followed by CT and HR-pQCT. If a scaphoid fracture was present, the fracture type was determined according to the Herbert classification system and correlation between CT and HR-pQCT was estimated with use of the Kendall W statistic or coefficient of concordance (W) (the closer to 1, the higher the correlation). RESULTS: The cohort included 45 men and 46 women with a median age of 52 years (interquartile range, 29 to 67 years). HR-pQCT revealed a scaphoid fracture in 24 patients (26%), whereas CT revealed a scaphoid fracture in 15 patients (16%). Patients with a scaphoid fracture were younger and more often male. The correlation between CT and HR-pQCT was high for scaphoid fracture type according to the Herbert classification system (W = 0.793; 95% confidence interval [CI], 0.57 to 0.91; p < 0.001) and very high for scaphoid fracture location (W = 0.955; 95%, CI 0.90 to 0.98; p < 0.001). CONCLUSIONS: In the present study, the number of patients diagnosed with a scaphoid fracture was 60% higher when using HR-pQCT as compared with CT. These findings imply that a substantial proportion of fractures-in this study, more than one-third-will be missed by the current application of CT scanning in patients with a clinically suspected scaphoid fracture. LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Regulation of phosphoenolpyruvate carboxykinase and tyrosine transaminase in hepatoma cell cultures. 3. Comparative studies in H35, HTC, MH1C1 and RLC cells.

The ability of N(6), O(2)'-dibutyryl cyclic AMP (DBcAMP) to regulate a number of metabolic events in four lines of cultured rat hepatomas has been examined. Although dexamethasone induces tyrosine transaminase in all four lines, DBcAMP induces this enzyme normally only in H35 cells. A slight increase in transaminase activity was seen with MH(1)C(1) cells and HTC cells, but no effect was detectable in RLC cells. In contrast, phosphoenolpyruvate carboxykinase activity is increased by both agents in H35 and MH(1)C(1) cells, but neither had any effect in HTC or RLC cells. DBcAMP caused a rapid inhibition of the growth rate and DNA synthesis and an increase in protein content in both H35 and MH(1)C(1) cells but not in HTC or RLC cells. The effect of DBcAMP on DNA synthesis in MH(1)C(1) cells could be reversed by deoxycytidine as is also the case with H35 cells. The resistance of HTC and RLC cells to DBcAMP was not due to reduced uptake or deacylation as judged by studies with [(3)H]DBcAMP. The cyclic nucleotide appears to enter the cells by passive diffusion as the intracellular concentration approaches that in the medium within 30-60 min. Possible explanations for the differential responses observed are discussed.

Modified uterine manipulator and vaginal rings for total laparoscopic radical hysterectomy.

At present, there is no standard technique that allows surgeons performing total laparoscopic radical hysterectomy to complete the colpotomy and remove an adequate (2-cm) margin of upper vaginal tissue while maintaining adequate pneumoperitoneum. We evaluated the feasibility and safety of using a modified uterine manipulator for total laparoscopic radical hysterectomy in patients with cervical or endometrial cancer. A retrospective review was performed in all patients who underwent total laparoscopic radical hysterectomy using a modified uterine manipulator at our institution during the period April 2004 to December 2006. This analysis included 30 patients who underwent surgery with the modified uterine manipulator. There were no reports of difficulty with placement of the instrument, multiple attempts at placement, difficulty with uterine manipulation, or uterine perforation. In no patient was a vaginal incision or episiotomy required to fit the instrument through the introitus. In no case was there loss of pneumoperitoneum during colpotomy. Additional upper vaginal tissue had to be removed after intraoperative assessment of the adequacy of the surgical specimen in five (16.7%) of 30 patients. Use of the modified uterine manipulator according to our technique is safe and feasible, allowing for adequate vaginal resection and maintenance of pneumoperitoneum.

DNA damage in bovine sperm does not block fertilization and early embryonic development but induces apoptosis after the first cleavages.

The main goal of this study was to investigate whether and at what level damage of paternal DNA influences fertilization of oocytes and early embryonic development. We hypothesized that posttesticular sperm DNA damage will only marginally affect sperm physiology due to the lack of gene expression, but that it will affect embryo development at the stage that embryo genome (including the paternal damaged DNA) expression is initiated. To test this, we artificially induced sperm DNA damage by irradiation with x- or gamma rays (doses of 0-300 Gy). Remarkably, sperm cells survived the irradiation quite well and, when compared with nonirradiated cells, sperm motility and integrity of plasma membrane, acrosome, and mitochondria were not altered by this irradiation treatment. In contrast, a highly significant logarithmic relation between irradiation dose and induced DNA damage to sperm cells was found by both terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) and the acridin orange assay. Despite the DNA damage, irradiated sperm cells did not show any sign of apoptosis (nuclear fragmentation, depolarization of inner mitochondrial membranes, or phospholipid scrambling) and were normally capable of fertilizing oocytes, as there was no reduction in cleavage rates when compared with nonirradiated sperm samples up to irradiation doses of less than 10 Gy. Further embryonic development was completely blocked as the blastocyst rates at days 7 and 9 dropped from 28% (nonirradiated sperm) to less than 3% by greater than 2.5-Gy-irradiated sperm. This block in embryonic development was accompanied with the initiation of apoptosis after the second or third cleavage. Specific signs of apoptosis, such as nuclear fragmentation and aberrations in spindle formation, were observed in all embryos resulting from in vitro fertilization with irradiated sperm (irradiation doses >1.25 Gy). The results show that sperm DNA damage does not impair fertilization of the oocyte or completion of the first 2-3 cleavages, but blocks blastocyst formation by inducing apoptosis. Embryos produced by assisted reproductive techniques (ART) could have incorporated aberrant paternal DNA (frequently detected in sperm of sub/infertile males). Analogously, in the present work, we discuss the possibility of following embryo development of oocytes fertilized by ART through the blastocyst stage before embryo transfer into the uterus in order to reduce risks of reproductive failure.

Effects of recombinant human follicle stimulating hormone on follicle development and ovulation in the mare.

The only gonadotrophin preparation shown to stimulate commercially useful multiple ovulation in mares is equine pituitary extract (EPE); even then, the low and inconsistent ovulatory response has been ascribed to the variable, but high, LH content. This study investigated the effects of an LH-free FSH preparation, recombinant human follicle stimulating hormone (rhFSH), on follicle development, ovulation and embryo production in mares. Five mares were treated twice-daily with 450 i.u. rhFSH starting on day 6 after ovulation, coincident with PGF(2alpha) analogue administration; five control mares were treated similarly but with saline instead of rhFSH. The response was monitored by daily scanning of the mares' ovaries and assay of systemic oestradiol-17beta and progesterone concentrations. When the dominant follicle(s) exceeded 35 mm, ovulation was induced with human chorionic gonadotrophin; embryos were recovered on day 7 after ovulation. After an untreated oestrous cycle to 'wash-out' the rhFSH, the groups were crossed-over and treated twice-daily with 900 i.u. rhFSH, or saline. At the onset of treatment, the largest follicle was <25 mm in all mares, and mares destined for rhFSH treatment had at least as many 10-25 mm follicles as controls. However, neither dose of rhFSH altered the number of days before the dominant follicle(s) reached 35 mm, the number of follicles of any size class (10-25, 25-35, >3 mm) at ovulation induction, the pre- or post-ovulatory oestradiol-17beta or progesterone concentrations, the number of ovulations or the embryo yield. It is concluded that rhFSH, at the doses used, is insufficient to stimulate multiple follicle development in mares.

Cationic liposome-mediated E1A gene transfer to human breast and ovarian cancer cells and its biologic effects: a phase I clinical trial.

PURPOSE: Preclinical studies have demonstrated that the adenovirus type 5 E1A gene is associated with antitumor activities by transcriptional repression of HER-2/neu and induction of apoptosis. Indeed, E1A gene therapy is known to induce regression of HER-2/neu-overexpressing breast and ovarian cancers in nude mice. Therefore, we evaluated the feasibility of intracavitary injection of E1A gene complexed with DC-Chol cationic liposome (DCC-E1A) in patients with both HER-2/neu-overexpressing and low HER-2/neu-expressing breast and ovarian cancers in a phase I clinical trial. PATIENTS AND METHODS: An E1A gene complexed with DCC-E1A cationic liposome was injected once a week into the thoracic or peritoneal cavity of 18 patients with advanced cancer of the breast (n = 6) or ovary (n = 12). RESULTS: E1A gene expression in tumor cells was detected by immunohistochemical staining and reverse transcriptase-polymerase chain reaction. This E1A gene expression was accompanied by HER-2/neu downregulation, increased apoptosis, and reduced proliferation. The most common treatment-related toxicities were fever, nausea, vomiting, and/or discomfort at the injection sites. CONCLUSION: These results argue for the feasibility of intracavitary DCC-E1A administration, provide a clear proof of preclinical concept, and warrant phase II trials to determine the antitumor activity of the E1A gene.

Nuclear and cytoplasmic maturation of sow oocytes are not synchronized by specific meiotic inhibition with roscovitine during in vitro maturation.

The effect of roscovitine exposure prior to IVM was studied on cumulus expansion, on changes of cumulus-oocyte contacts and on nuclear and cytoplasmic maturation of sow oocytes. It was hypothesized that delayed nuclear maturation and prolonged contact with cumulus cells allows prolonged cytoplasmic differentiation and therefore improves oocyte developmental potential. Cumulus-oocyte complexes (COCs) were exposed for 22 h or 44 h to 0, 25 or 50 microM of roscovitine and subsequently cultured for 22, 29 or 44 h without roscovitine. COCs were examined for cumulus expansion and oocytes for nuclear status and dynamics of transzonal microfilaments. Oocyte developmental potential was assessed by blastocyst formation after IVF. Fifty muM of roscovitine inhibited cumulus expansion for the first 22 h of culture, and maintained oocytes in meiotic arrest for 44 h. Roscovitine treatment during 22 h prior to culture for 44 h without roscovitine did not increase embryo development, but oocytes cultured for 66 h without roscovitine had reduced blastocyst formation. Oocytes cultured for 29 h after roscovitine exposure showed reduced blastocyst rates compared with their counterparts cultured for 44 h. Roscovitine treatment during 44 h prior to culture for 22 h or 44 h without roscovitine reduced embryo development. Transzonal microfilaments were reduced after culture with roscovitine, and disappeared during culture without roscovitine. It is concluded that prolonged contact with cumulus cells does not improve oocyte developmental potential. Furthermore, it is suggested that nuclear and cytoplasmic maturation in vitro cannot be seen as two independent processes.

Expression of bone morphogenetic protein2 (BMP2), BMP4 and BMP receptors in the bovine ovary but absence of effects of BMP2 and BMP4 during IVM on bovine oocyte nuclear maturation and subsequent embryo development.

Bone morphogenetic proteins (BMPs) have been implicated in the regulation of ovarian follicular development and are promising candidates to apply in IVM and IVF protocols. We investigated the expression of BMP2, BMP4 and BMP receptors in bovine ovaries and the effects of BMP2 and BMP4 during oocyte maturation on bovine IVM. Reverse transcription polymerase chain reaction studies with antral follicles showed the expression of BMPR-IA, BMPR-IB, ActR-IA, ActR-IIB, BMPR-II and BMP4 mRNA in all follicular compartments, while BMP2 mRNA was generally restricted to theca and cumulus tissue. Immunohistochemistry demonstrated the presence of BMPR-II in oocytes and granulosa cells of preantral follicles but only in oocytes of antral follicles. The immunostaining of BMP2 and BMP4 was limited to theca interna and approximately 25% of oocytes of antral follicles. Exogenously added BMP2 or BMP4 to IVM medium did not affect oocyte nuclear maturation, cumulus cell expansion, nor blastocyst formation following IVF. It is concluded that a BMP-signaling system, consisting of BMP2, BMP4, type II and I receptors, is present in bovine antral follicles and that this system plays a role in development and functioning of these follicles rather than in final oocyte maturation and cumulus expansion.

Differential cardiovascular and neuroendocrine effects of epinine and dopamine in conscious pigs before and after adrenoceptor blockade.

1. The effects of epinine or dopamine (both 1-10 micrograms kg-1 min-1) on systemic haemodynamics and plasma concentrations of catecholamines and prolactin were studied in conscious pigs before and after combined non-selective alpha- and beta-adrenoceptor blockade. 2. The plasma concentrations of the two compounds did not differ from each other over the entire dose-range. 3. Epinine increased aortic blood flow (AoBF, 24 +/- 6%), which was due to an increase in heart rate (HR) for doses less than 10 micrograms kg-1 min-1. At 10 micrograms kg-1 min-1, HR decreased slightly (10 +/- 3%, as compared to the value obtained at 5 micrograms kg-1 min-1) and stroke volume increased up to 15% (P < 0.05). Mean arterial pressure (MAP, 99 +/- 3 mmHg at baseline) decreased dose-dependently (14 +/- 2%, P < 0.05) up to the infusion rate of 5 micrograms kg-1 min-1, but increased by 4.0 +/- 1.8 mmHg during infusion of 10 micrograms kg-1 min-1. Systemic vascular resistance (SVR) decreased up to 23 +/- 3% for doses less than 10 micrograms kg-1 min-1, but did not change further during infusion of the highest dose. LVdP/dtmax increased during the two highest infusion rates up to 22 +/- 6% (P < 0.05). After the infusion was stopped there was an abrupt increase in HR (18 +/- 4%, P < 0.05) and a further decrease in SVR before all parameters returned to baseline.4. Dopamine caused increases in AoBF (27 +/- 3%) similar to epinine, the only difference being that HR continued to increase (32 +/- 5%) and MAP (13 +/- 3%) and SVR continued to decrease (31 +/- 3%) over the entire dose-range. The increase in LVdP/dt,,,, at the highest dose (48 +/- 4%, P <0.05) was more pronounced than with epinine.5. Adrenoceptor blockade inhibited all epinine-induced changes, but did not affect the dopamineinduced changes in AoBF, SVR and MAP, but attenuated the increases in HR and LVdP/dtmax.6. Noradrenaline (NA) and adrenaline (Ad) concentrations did not change during infusion of epinine or dopamine, but NA increased by 50% within 2.5 min after stopping the infusion of epinine. After adrenoceptor blockade NA and Ad concentrations did not change during infusion of dopamine, which contrasted with a decrease of 55 +/- 5% (P<0.05) in NA during infusion of epinine.7. Prolactin concentrations decreased gradually from 480 +/- 40 pg ml-' to 270 +/- 50 pg ml1' (P<0.05) during infusion of epinine, but did not change significantly during dopamine infusion.8. The differential effects of epinine and dopamine on MAP, SVR, plasma NA (before and after adrenoceptor blockade) and prolactin, leads us to conclude that in conscious pigs, epinine is a more potent a, P2 and D2-receptor agonist, but a weaker D,-receptor agonist than dopamine.

Alterations in anterior pituitary function of dogs with pituitary-dependent hyperadrenocorticism.

For the purpose of obtaining an integral picture of anterior pituitary function in canine pituitary-dependent hyperadrenocorticism (PDH), 47 dogs with PDH and eight control dogs received combined administration of four hypophysiotropic hormones (CRH, GHRH, GnRH and TRH) and measurements were made of ACTH, cortisol, GH, LH, PRL and TSH. Basal plasma levels in 47 dogs with PDH were higher for ACTH, cortisol and PRL, lower for GH, and not different for LH (n = 25 noncastrated dogs) and TSH compared with controls (n = 8). In dogs with PDH the responses to combined hypophysiotropic stimulation, measured as increment and area under the curve (AUC), were not different for ACTH, lower for GH and TSH (increments and AUC) and higher for cortisol (increments), LH (AUC, n = 25 noncastrated dogs) and PRL (increments and AUC) than in controls. We conclude that pituitary function is altered in several respects in dogs with PDH. 1) In spite of persisting hypercortisolemia and the neoplastic transformation of the corticotropic cells, these cells usually remain responsive to combined hypophysiotropic stimulation. 2) Basal plasma GH concentrations and GH responsiveness in the combined stimulation test are decreased, probably as a result of the glucocorticoid-induced increase in somatostatin tone. 3) Plasma PRL concentrations and the PRL response to stimulation are increased, probably as a result of cosecretion with ACTH by the transformed corticotropic cells. 4) Despite the well known effect of glucocorticoids of decreasing circulating concentrations of gonadal steroids and thyroxine, the basal plasma concentrations of LH and TSH remain unchanged and there is a tendency to hyperresponsiveness to stimulation for LH and hyporesponsiveness for TSH. The most likely explanation for these changes is a dual effect of glucocorticoids: a direct effect on the gonads and thyroids and/or the transport and metabolism of their secretory products, and an influence on the sensitivity of the feedback control at the hypothalamic-pituitary level.

Residual pituitary function after transsphenoidal hypophysectomy in dogs with pituitary-dependent hyperadrenocorticism.

Pituitary function was assessed before and after transsphenoidal hypophysectomy in 39 dogs with pituitary-dependent hyperadrenocorticism (PDH). Anterior pituitary function was investigated using combined administration of four hypophysiotropic releasing hormones (corticotropin-releasing hormone (CRH), GHRH, GnRH, and TRH) with measurements of ACTH, cortisol, GH, LH, prolactin (PRL), and TSH Pars intermedia function was assessed by measurements of basal plasma alpha-MSH concentrations and adrenocortical function by baseline urinary corticoid/creatinine ratios. At eight weeks after hypophysectomy basal plasma ACTH, cortisol, GH, LH, PRL, and TSH concentrations were significantly lower than before surgery. In seven dogs with elevated alpha-MSH concentrations, the values returned to the normal level after surgery. In the combined anterior pituitary function test there were no plasma GH, LH, PRL, and TSH responses to stimulation, whereas plasma ACTH and cortisol responses were small but significant. Remission of hyperadrenocorticism was obtained in 35 dogs and recurrences occurred in 3 of these within 16 months postoperatively. At 8 weeks after hypophysectomy, these 3 dogs were not discernible, with respect to residual pituitary and adrenocortical function, from the 32 dogs with persisting remission. Urinary corticoid/creatinine ratios in the latter group of dogs did not increase during 22 months after hypophysectomy. In contrast to the presurgical findings, at 8 weeks after hypophysectomy there were significant positive correlations between baseline urinary corticoid/creatinine ratios and basal levels and responses for ACTH, indicating return to normal function of the pituitary-adrenocortical axis. It is concluded that among the adenohypophyseal cells present in the sella turcica after hypophysectomy, the corticotropes have a distinct behavior. Much more so than the other cell types, the unaffected corticotropes tend to remain functional, or a repressed reserve fraction of corticotropes may become functional. This may be due to the removal of the hypothalamic influence of a postulated corticotropin-release inhibiting factor or a diminished inhibitory influence of a postulated paracrine factor. The corticotropes may maintain normocorticism, but may also lead to mild recurrence after relatively long periods of remission.

Effects of morphine and naloxone on plasma levels of LH, FSH, prolactin and growth hormone in the immature male pig.

The effects of acute i.v. administration of gonadotrophin-releasing hormone (GnRH; 0.1 micrograms/kg), morphine (3 mg/kg) and/or naloxone (0.5 mg/kg) on LH and FSH secretion was evaluated in young male pigs (approximately 6 weeks old) with venous brachiocephalic cannulae. The effects of morphine and/or naloxone treatments on prolactin and GH were also evaluated. The influence of morphine on hypophysial hormone secretion was also examined 2 days after castration. Animals treated with morphine and/or naloxone were compared with saline-injected control animals. Injection of GnRH induced 400 and 50% increases in LH and FSH respectively. Morphine and/or naloxone did not influence LH secretion in intact or castrated animals. Morphine suppressed (P less than 0.01) FSH levels 40-60 min after injection whereas naloxone had no effect. Castration eliminated morphine-induced suppression of FSH. Injection of morphine followed by naloxone resulted in acutely raised (P less than 0.05) FSH concentrations. Morphine induced a threefold increase (P less than 0.01) in prolactin within 30 min of injection and naloxone inhibited the effect of morphine. Levels of GH were increased (P less than 0.01) 20 min after morphine treatment and this increase was delayed when naloxone was given immediately after morphine. Naloxone alone did not affect prolactin or GH secretion. Castration caused increases in LH (P less than 0.05) and FSH (P less than 0.01), did not influence prolactin or GH, and reduced plasma testosterone to undetectable (less than 1.0 nmol/l) levels. These results suggest that in young male pigs the hypothalamic-hypophysial axis is responsive to GnRH and gonadal negative feedback.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibin, gonadotrophins and sex steroids in dogs with Sertoli cell tumours.

Inhibin bioactivity and mRNA for inhibin subunits were measured in four dog Sertoli cell tumours and in the testes of five normal control dogs. The tumours contained increased levels of inhibin (P less than 0.05) and mRNA for the alpha and beta B subunits when compared with controls, whereas the mRNA for the beta A subunit was not detected in tumours or control testes. The inhibin bioactivity was associated with a 32 kDa molecule in both Sertoli cell tumours and normal dog testes; no higher molecular weight forms were found after sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Peripheral levels of immunoassayable inhibin in dogs with Sertoli cell tumours were higher than those in the controls (P = 0.01), indicating that it might be possible to use this parameter as a marker for Sertoli cell tumours. Other testicular tumours, however, might also secrete immunoactive inhibin. The increased inhibin concentrations are likely to be the cause of the suppressed peripheral levels of FSH (P less than 0.02). However, peripheral levels of LH (P less than 0.02) and testosterone (P less than 0.01) were also suppressed in the dogs with Sertoli cell tumours, whereas the concentrations of oestradiol in the peripheral plasma of both groups did not differ. Finally, i.v. injection of the LHRH agonist buserelin caused a significant increase in LH and testosterone in the control dogs, but not in the dogs with Sertoli cell tumours. It was concluded that secretory products from the Sertoli cell tumours suppressed pituitary gonadotrophin secretion. It is unlikely that testosterone or oestradiol play a role in this respect. FSH may be suppressed by the high levels of inhibin in tumour-bearing dogs, but it remains unclear whether inhibin or another Sertoli cell product is responsible for the unresponsiveness of the pituitary gland to LHRH and the suppression of LH.

15-Hydroxy-prostaglandin dehydrogenase activity in uterine tissues of late gestational and parturient cows.

15-Hydroxy-prostaglandin dehydrogenase activity (PGDH) was measured in endometrium, allanto-chorion, allanto-amnion and the placenta from six cows during late gestation and six parturient cows during caesarean section. Under saturated substrate conditions PGDH activity was lower than 138 pmol g wet tissue-1 min-1 in all uterine tissues in both groups. Human placental reference samples showed a PGDH activity of 16,800 +/- 1200 pmol per g wet weight min-1 (n = 4). Under subsaturational conditions enzyme activity was demonstrated in endometrium and both fetal membranes. These results indicate that PGF2 alpha catabolism in bovine uterine tissue on day 262 and during parturition, contributes little to changing plasma PGFM concentrations.

Role of growth hormone and growth hormone receptor in oocyte maturation.

Near the completion of growth, mammalian oocytes acquire the competence to resume and complete meiosis. In vivo the preovulatory LH surge triggers the resumption of meiosis in the oocyte contained in preovulatory follicles. When immature oocytes and the surrounding cumulus cells are released from their follicular environment, resumption of meiosis is induced spontaneously. Culture of bovine cumulus oocyte complexes (COCs) obtained from antral follicles results in blastocyst formation following in vitro maturation, in vitro fertilisation and in vitro embryo culture. Addition of growth hormone (GH) to the maturation medium accelerates nuclear maturation of cumulus enclosed bovine oocytes, induces cumulus expansion and promotes early embryonic development following in vitro fertilisation. The effect of GH is exerted through the cumulus cells and not mediated by IGF-I. Cumulus cells and the oocyte express mRNA for GH receptor. Using specific inhibitors it has been shown that the effect of GH on oocyte maturation and cumulus expansion is mediated by the cyclic AMP signal transduction pathway. Within COCs both cumulus cells and oocyte show GH immunoreactivity while expression of GH mRNA is only found in the oocyte. These observations point to a paracrine and/or autocrine action of GH in oocyte maturation.