Can 18F-FDG-PET show differences in myocardial metabolism between Wistar Kyoto rats and spontaneously hypertensive rats?

Positron emission tomography (PET) is useful for evaluating the cardiac metabolism of free fatty acid, glucose and oxygen both in human clinical practice and in experimental animal models. However, no data are available for such an evaluation in a model of stable compensated left ventricular hypertrophy in 14-month-old spontaneously hypertensive rats (SHRs). This study was designed to assess the metabolism of myocardial glucose in SHRs using 2-deoxy-2-[18F]fluoro-D-glucose ((18)F-FDG) using PET. The study was performed on 14-month-old male SHRs (n = 4) and age-matched Wistar Kyoto (WKY) rats (n = 4). PET scans were performed after the administration of anaesthesia with isoflurane and injection of a bolus of 39.37 ± 3.25 (mean ± SD) MBq (1.06 mCi) of (18)F-FDG. The standardized uptake value (SUV) was used to evaluate (18)F-FDG uptake by the heart. The analysis of SUV showed increased metabolism in the left ventricle of SHRs compared with WKY rats. Our results show that small animal PET using (18)F-FDG can be performed in 14-month-old SHRs to evaluate new therapies in the regression of left ventricular hypertrophy in SHRs because pathological myocardial metabolism in the SHR differs from the normal metabolism of the WKY rat.

Filogenia de la articulación de la cadera. Plasticidad del fenotipo. ¿Paradigma Lamarckiano o Darwiniano? Parte II / Hip Joint phylogenesis. Phenotypic plasticity. Lamarckian or Darwinian paradigm? Part II

Objetivo. El objetivo de este trabajo es analizar el origen de los cambios plásticos del fenotipo en una estructura biológica, en nuestro caso la cadera. Como hipótesis de trabajo se presenta la posibilidad de que los cambios se puedan interpretar según el paradigma Lamarckiano, en contraposición al paradigma Darwiniano. La sección material y método del trabajo se menciona en la parte I. Se han añadido estudios de plantas y peces. Discusión. Los resultados muestran que el diseño de la cadera, como relación de bola y cuenco, no cambia. El fenotipo, en los elementos que costituyen los tejidos de la articulación de la cadera, muestra cambios plásticos significativos. Conclusión. Sugerimos: que los cambios de la plasticidad del fenotipo de la cadera son inmanentes al fenotipo, y no se interpretan según el paradigma Lamarckiano ni Darwiniano (AU)

Objective. The aim of this work is to analyse the origin of phenotypic plastic changes into a biologic structure, in this case the hip. As a hypothesis of the work, the possibility that changes could be explained following the Lamarckian paradigm, opposed to the Darwinian paradigm, is shown. The section material and methods of this work have been published in part I. Studies in plants and fish have been added. Discussion. Results showed that the ball-and-socket design of the hip joint remains unchanged. Phenotype in the elements that form the hip joint tissues showed significant plastic changes. Conclusion. Interpretation of our results suggest that changes in phenotype plasticity of the hip joint are immanent to phenotype and cannot be explained by following Lamarck's or Darwin's paradigm (AU)

[Hip Joint phylogenesis. Phenotypic plasticity. Lamarckian or Darwinian paradigm? Part II]. / Filogenia de la articulación de la cadera. Plasticidad del fenotipo. ¿Paradigma Lamarckiano o Darwiniano? Parte II.

OBJECTIVE: The aim of this work is to analyse the origin of phenotypic plastic changes into a biologic structure, in this case the hip. As a hypothesis of the work, the possibility that changes could be explained following the Lamarckian paradigm, opposed to the Darwinian paradigm, is shown. The section material and methods of this work have been published in part I. Studies in plants and fish have been added. DISCUSSION: Results showed that the ball-and-socket design of the hip joint remains unchanged. Phenotype in the elements that form the hip joint tissues showed significant plastic changes. CONCLUSION: Interpretation of our results suggest that changes in phenotype plasticity of the hip joint are immanent to phenotype and cannot be explained by following Lamarck's or Darwin's paradigm.

Severe hypoxaemia with a left ventricular assist device in a minipig model with an undiagnosed congenital cardiac disease.

We describe the placement of a left ventricular assist device (LVAD) in a pig with spontaneously occurring atrial septal defect (ASD) (incidental finding) that created a right-left cardiac shunt, with subsequent severe hypoxaemia. Early diagnosis was critical in order to prevent end-organ damage due to hypoxaemia. Adequate monitoring alerted us to the deterioration in oxygenation, haemodynamics and cerebral oxygen metabolism. This forced us to change the level of assistance provided by the pump, and thus dramatically correct this impairment. Necropsy revealed an ostium secundum ASD. In conclusion, if hypoxaemia presents after implementation of an LVAD, the presence of a right-left shunt must be ruled out. The first step must be a judicious reduction in assist device flow to minimize intracardiac shunting. Subsequently, atrial septal closure of the defect should be considered. We report an experimental model of severe hypoxaemia after placement of an LVAD as part of a larger research project.

An approach to comparative anatomy of the acetabulum from amphibians to primates.

The objective of this study was to investigate the anatomy, both macroscopic and microscopic, of the soft tissue internal structures of the hip joint in animal species and in three human hips (an adult and two fetuses). We dissected the hip joints of 16 species and compared the anatomical features of the soft tissue from the respective acetabula. In addition, a histological study was made of the specimens studied. In amphibians, we found a meniscus in the acetabulum, which was not observed in any of the other species studied. The isolated round ligament is observed from birds onwards. In the group of mammals analysed, including the human specimens, we found a meniscoid structure in the acetabular hip joint. Furthermore, we found that the meniscoid structure forms an anatomo-functional unit with the round ligament and the transverse ligament of the coxofemoral joint. These discoveries suggest the participation of the soft tissue anatomy in adaptative changes of species.

Evolutional patterns of articular cartilage following growth plate injury in rats.

BACKGROUND: No study to date has analyzed the damage of the articular cartilage and its relation to growth plate injury. The purpose of this study was to test whether primary injury to the growth plate contributes to secondary damage to the articular cartilage in rats. METHODS: A total of 109 two-week-old male Wistar rats were allocated to four lesional groups. In group I (controls) no surgery took place. In the remaining animals, an injury was caused in the proximal physis of the left tibia: group II, perichondrial ring injury; group III, direct injury to the growth plate; group IV, traumatic separation of the epiphysis where a Salter-Harris II-type injury was created. The results were assessed at 1 week, 6 weeks, and 6 months. A growth plate score was used. The stereological and histological changes in the articular cartilage were analyzed, and the results were subjected to statistical analysis. RESULTS: Histological studies showed discrete degenerative changes in the articular cartilage in the injured growth plate. Changes in the cell density, mean cell volume, and articular cartilage occurred in the injured growth plate. The changes appeared to be transient in groups II and III. CONCLUSIONS: Primary injury to the growth plate contributes to secondary damage to the articular cartilage in young rats. Our data -- extrapolated to the clinical view -- suggests that a Salter-Harris type II injury does not seem to have impunity to subsequent joint degeneration.

Ultrasound validity in the measurement of knee cartilage thickness.

OBJECTIVE: To assess the multiexaminer reproducibility and the accuracy comparing with cadaver anatomic specimens of ultrasound (US) measurement of femoral articular cartilage (FAC) thickness. METHODS: In 8 flexed cadaver knees, FAC thickness was blindly, independently and consecutively measured twice by 10 rheumatologists at the lateral condyle (LC), medial condyle (MC) and intercondylar notch (IN) with US. After the US measurements, the knees were dissected. Articular cartilage integrity was evaluated macroscopically in the femoral condyles. FAC thickness was blindly measured in the specimens using a stereoscopic magnifying loupe and a digitised image software. Interexaminer and intraexaminer reliability of US FAC thickness measurement and agreement between US and anatomic measurements were assessed by estimating the intraclass correlation coefficient (ICC). RESULTS: Interexaminer ICCs were higher than 0.90 for MC (p<0.001) and IN (p<0.001) and higher than 0.75 for LC (p<0.01). Mean intraexaminer ICCs were 0.832 for MC (p<0.001), 0.696 for LC (p<0.001) and, 0.701 for IN (p<0.001). Agreement between US and anatomic FAC thickness measurements was good for MC (ICC 0.719; p = 0.020) and poor for LC (p = 0.285) and IN (p = 0.332). Bland-Altman analysis showed that the difference between US and anatomic values was considerably high in the one knee with severely damaged FAC. After eliminating this knee from the analysis, ICCs were 0.883 (p<0.001) for MC, 0.795 (p = 0.016) for LC and 0.732 for IN (p = 0.071). CONCLUSION: US demonstrated a good reproducibility in FAC thickness measurement by multiple examiners. In addition, US FAC thickness measurement was accurate in normal to moderately damaged cartilage.

Correlation between arthroscopic and histopathological grading systems of articular cartilage lesions in knee osteoarthritis.

PURPOSE: Arthroscopic and particularly histopathological assessments have been used to evaluate alterations of knee cartilage in osteoarthritis (OA). The aim of this study was to examine the correlation between an arthroscopic method to grade the severity of chondropathies and the histological/histochemical grading system (HHGS) applied to the corresponding articular cartilage areas in knee OA. METHODS: The articular cartilage surface was examined by chondroscopy using the Beguin and Locker severity criteria, analysing the lesions in 72 chondroscopic areas. Afterwards, samples were obtained by dividing the cartilage surface of the medial tibiofemoral compartment of three OA knee joints into equal squares and they were evaluated histologically using the HHGS. The correlation between both grading methods was assessed using the weighted Kappa coefficient (K(w)). RESULTS: The results obtained with both scores showed good agreement (K(w): mean+/-standard deviation, 0.619+/-0.071). While the average HHGS scores of the chondral samples showed a better agreement with arthroscopic grades 0, I and II, the arthroscopic evaluation has a tendency to overestimate chondral lesions for histological grades III and IV. The intra- and inter-observer reliability of the HHGS evaluation of chondral lesions was excellent (Intraclass Correlation Coefficient: 0.909 and 0.941, respectively). CONCLUSION: In this study, we found a good quantitative correlation between established arthroscopic severity and histopathological scoring systems, particularly in less advanced lesions. Our results suggest that the arthroscopic method is a valuable tool in clinical research to score chondropathies in the medial femorotibial compartment of the OA knee, although some limitations should not be overlooked.

The fate of chondrocyte in osteoarthritic cartilage of transgenic mice expressing bovine GH.

OBJECTIVE: The aim of the present study was to demonstrate whether bGH transgenic mice develop OA. We therefore studied in this animal model the structural features of cartilage and the subchondral bone changes of the knee joints that may be associated with osteoarthritic lesion. METHOD: Degenerative changes in the knee joints of bGH transgenic female mice (N = 11) and control mice (N = 11) were histologically analyzed at the age of 7 months. Histochemical and stereological studies were conducted. Immunohistochemistry on cell cyclin activity (assessed by anti-PCNA labeling) and cell viability (assessed by bcl-2 expression), as well as ribosomal activity (AgNOR), TNF-alpha expression and apoptosis (TUNEL technique) were performed. In ten 7-month-old female mice (Tg+ N = 5; control N = 5) the knee articular cartilages were studied with electron microscopy techniques. RESULTS: Disruption of the articular surface (18.2%), cleft (63.7%), cloning (81.8%), hypocellularity of chondrocytes (18.2%), moderate (54.6%) to severe (45.4%) loss of safranin-O staining, and duplication and rupture of the tidemark (54.5%) were some of the main features observed in articular cartilage chondrocytes of bGH transgenic mice. Furthermore, cell cyclin activity and cell viability decreased, while TNF-alpha expression and TUNEL+ cells increased. These chondrocytes also showed an increase in the number of black dots per cell, as revealed by the AgNOR technique. CONCLUSION: Our results show that bGH transgenic mice develop a lesion of the articular cartilage consistent with that described in osteoarthritis.

Expression of CCAAT/enhancer-binding protein-beta (C/EBPbeta) and CHOP in the murine growth plate. Two possible key modulators of chondrocyte differentiation.

Our aim was to evaluate the expression of transcription factors CCAAT/enhancer-binding protein-beta (C/EBPbeta) and C/EBP-homologous protein (CHOP) in the growth plate. Proximal tibial epiphyseal growth plates from ten 15-day-old Wistar rats were used. Additionally, anti-proliferating cell nuclear antigen (PCNA), anti-5-bromo-2'-deoxyuridine (BrdU) immunostaining, terminal transferase dUTP nick end-labelling (TUNEL) and nucleolar organiser region-associated proteins (AgNOR) techniques were peformed. The histological morphology of the growth plate from C/EBPbeta knock-out mice was also analysed. The normal growth plate showed that C/EBPbeta and CHOP factors are expressed both in the germinative/ upper proliferative and in the lower proliferative zones. Furthermore, BdrU+ and PCNA+ cells were present exclusively in the germinative and proliferative zones, while TUNEL+ and AgNOR+ cells were seen in all three zones of the growth plate. Acellular areas, hypocellularity, the increase in cell death and anomalies in the architecture of the cell columns were observed in the growth plates of C/EBPbeta (-/-) knockout mice. We suggest that C/EBPbeta and CHOP transcription factors may be key modulators participating in the chondrocyte differentiation process in the growth plate.

Transgenic mice expressing bovine GH develop arthritic disorder and self-antibodies.

We observed disability of movement in 6-month-old transgenic mice expressing the fusion gene coding for the bovine GH (bGH) under the transcriptional control of phosphoenolpyruvate carboxykinase promoter (PEPCK-bGH). Histological study of the knee joint showed altered synovial and tibial articular cartilage tissues. In the cartilage the following observations were made: (i) generalized loss of the normal zonal structure and presence of clefts, and (ii) profound alterations in chondrocyte growth/differentiation processes consistent with hypertrophy. The synovial tissue showed a reduced number of adipocytes, and a significant thickening of synovial lining tissue and pannus. These findings indicate that transgenic mice suffer damage to diarthritic joints with osteoarthritic appearance. As changes in synovial membrane in osteoarthritis are almost indistinguishable from those seen in inflammatory arthritis, we determined the potential correlation with an immunological disorder. Serological determination of self-antibodies measured as a function of age and sex showed anti-nuclear, anti-single-stranded DNA, anti-double-stranded DNA and anti-70K antibodies, and an altered immunoglobulin typing. These results suggest that transgenic mice expressing bGH develop an arthritic process which is correlated with an immune disorder. The results also indicate that these mice are a suitable animal model to study the specific role of GH-driven processes in immune cells and arthritis.

Mechanoreceptors in collateral knee ligaments: an animal experiment.

The mechanoreceptors in the collateral ligaments of the knee joint in rat hindlimbs were studied. In group II (n=10) the femoral and obturator nerves were sectioned. In both groups III and V (n=20) the sciatic nerve was sectioned. In group V (n=10) the sectioned sciatic nerve was sutured 4 weeks after sectioning. In group IV (n=10) all three nerves were sectioned. Group I (n=10) served as control. After 4 months all animals were killed. The ligaments of the knee joint were preserved and stained with gold chloride, paraffin-embedded and cut in sagittal serial sections. The results showed that 4 months after partial or total denervation of the limb, there was necrosis and a decrease in the number of mechanoreceptors, which was dependent upon the severity and site of the lesion. After suture of the sciatic nerve the increase in mechanoreceptors suggested a regenerative process.

Retinoic acid-induced clubfoot-like deformity: pathoanatomy in rat fetuses.

The purpose of this assay was to study the hindfoot patho-dynamic in clubfoot-like deformity during fetal development. Experimental induction of clubfoot-like deformity in rat fetuses was produced by maternal administration of retinoic acid (120 mg/kg body weight) as a single intragastric dose on day 10 of pregnancy. Hindlimbs from fetuses at 17, 19, and 21 days were removed, and serial sections in three planes were made. Experimental and control hindlimbs were studied. There was clubfoot-like deformity in 86.5% of the experimental fetuses and none in the controls. Other associated malformations found were craniofacial (96.3%), neural tube (75.7%), and club-hand (40.3%) defects. Persistence of the embryonic position of the talus and tibia in fetuses with severe clubfoot-like deformity was observed. No overlapping between talus and calcaneus was seen. An equinus position, medialization of anterior segment, and lateralization and inward torsion of the posterior body of the calcaneous were observed. Results of this study showed that there are rotational anomalies in the hindfoot and full hindlimb from the beginning of the fetal period, and these anomalies increase during development. This simple model may allow us to gain better knowledge in congenital clubfoot deformity.

Neural tube defects: an experimental model in the foetal rat.

We report on our experience in the experimental induction of Neural Tube Defects (NTD) in the foetal rat by maternal administration of retinoic acid. The teratogen diluted in olive oil was administered in a single intragastric dose (125 mg/kg body weight) to pregnant rats (n = 31) on the 10th day of gestation. Pure olive oil was given to control rats (n = 9). The foetuses were recovered by caesarian section on the 20th day and prepared for morphological investigation. We have studied 201 experimental and 82 control animals. There were NTD in 36.3% of experimental foetuses and none in the control ones. Sacral dysraphism was the most frequent defect but we also observed Arnold Chiari malformations and crowding of the bony limits by an enlarged neural axis. Other associated malformations found were: craneofacial (78.1%), caudal (80%), anorectal (31.4%), and limb defects (89.5%). This simple and inexpensive model may allow us to gain a better knowledge of the biology in the foetus with NTD.

Cartilage canals in the tarsal navicular of the human foetus and infant.

We have analysed the development of the cartilage canals in the tarsal navicular in 26 human foetuses and infants, aged between 12 weeks after gestation and 10 months, using a technique of transparentation and serial histological sections of the bone. The formation of cartilage canals starts in the first 12 to 13 weeks of gestation and can be seen by transparentation at 17 weeks after gestation. They increase in number with the age of the foetus or infant and develop a branching pattern almost to the centre of the tarsal navicular. They begin and are more numerous on the dorsal surface of the cartilage structure.

Histomorphometric analysis of the epiphyseal growth plate in rats after prenatal alcohol exposure.

We studied the effect of prenatal alcohol exposure on growth in the proximal tibial growth plate in 0- and 15-day-old rats, using histomorphometric methods. Body weight and tibial length were reduced in all alcohol-exposed rats. In 15-day-old rats, these parameters were lower than in the 15-day-old controls, thus showing a persistence of the effects of ethanol. The proximal tibial growth plate showed alterations, principally in 15-day-old rats. The most notable of these was a decrease in growth plate height produced by a significant reduction in hypertrophic zone height. Likewise, there were fewer cells in this zone in alcohol-exposed rats than in controls. This work shows that prenatal ethanol exposure induces growth retardation which may be due to growth plate alterations that might reflect impaired cell function.

Why does pelvic deformity occur in experimental dislocation of the growing hip?

A three-dimensional pelvic deformity was observed when experimental dislocation of the hip was reproduced in Wistar rats using hormonal and biomechanical factors. Resection or surgical dislocation of the femoral head created its absence in the acetabular socket without pelvic deformity. Muscular contractures were observed in all animals. We conclude that progressive displacement of the femoral head could produce pelvic deformity and simultaneous alterations in the triradiate cartilage.

Cartilage canal growth: experimental approach in the rat tibia.

This paper studies the influence of an antimitotic factor (puromycin) and a hormonal factor (thyroid hormone, TH) on canal growth. The tibiae of 15 six-day-old rats were cultured in a serum-free chemically defined medium. The cultures were carried out for as long as 6 days. Our results show: (1) canal growth is not dependent on perichondrium or chondro-epiphysis growth; (2) the canal is greater and has a complex pattern in a triiodothyronine (T3)-treated assay group; (3) round and multinucleated cells are more numerous in the T3-treated assay group than in the other groups. We hypothesize that the canal grows by a physiological phenomenon of programmed cell death and that it is stimulated by TH.

Pelvic deformity in experimental dislocation of the growing hip.

The hip joints of growing rats have been dislocated experimentally to determine how this affects pelvic shape and acetabular orientation. After hip dislocation the innominate bone tilts laterally in the frontal plane. It bends anteriorly in the sagittal plane and rotates contralaterally in the coronal plane. No significant acetabular anteversion develops.

Growth of the perichondrium and the chondroepiphysis: experimental approach in the rat proximal tibial epiphysis.

In the present paper we study the participation of the perichondrium in chondroepiphysis development analyzing its in vitro growth pattern without the perichondrium. We also advance the descriptive morphological results. We have observed that the chondroepiphysis without perichondrium grew with an almost normal pattern. Most of the cells that participated in chondroepiphysis growth came from the lateral region of the growth plate.