Computer-assisted fronto-facial monobloc advancement and facial bipartition for Pfeiffer's Syndrome: the surgical technique

INTRODUCTION

In the Pfeiffer syndrome, several corrections are required to correct the facial retrusion, the maxillary deficiency or even the hypertelorism. The fronto-facial monobloc advancement (FFMA) and the facial bipartition (FB) are the gold standard surgeries. We present the correction of this deformity using a simultaneous computer-assisted FFMA and FB.

TECHNICAL NOTE

The 3D surgical planning defined the virtual correction and the bone cutting guide in view of the FFMA and the FB. Coronal and intraoral approaches were combined to perform the osteotomies. Four internal distractors were also placed for the postoperative distraction osteogenesis.

DISCUSSION

Computer-assisted surgery is helpful and a reliable option for the management of complex facio-craniosynostosis such as hypertelorism and fronto-facial retrusion.

Is reverse frontal cranioplasty eligible for the correction of both the forehead deformities and the intracranial hypertension in craniosynostosis? Comparison of the preoperative and postoperative intracranial volumes

BACKGROUND

This study aimed to describe the surgical technique of reverse frontal cranioplasty (RFC), the aesthetical modification as well as the modification of intracranial volume (ICV) to assess its potential eligibility for the treatment of the intracranial hypertension (IH).

MATERIALS AND METHODS

A retrospective monocentric study included the patients with a history of craniosynostosis with a forehead deformity who underwent RFC. A subjective outcome questionnaire (SOQ) was conducted with each patient or their parent to determine their level of satisfaction after RFC. Pre- and postoperative computed tomography (CT) scans were analyzed and compared to investigate the ICV change and fronto-nasal angle.

RESULTS

Eleven patients were included in the study (6 female and 5 male) with a mean age of 10.9 years old (range 3-23 years) and an average follow-up of 4.5 years (1-11 years). All patients responded to the questionnaire with a high level of overall satisfaction (mean 9.1/10). The mean preoperative FNA was 134° ± 5° while the mean postoperative angle was 126.4° ± 6, corresponding to an average decrease of 7.6° (95% CI, 4.0-11.2°; p < 0.001). One patient with preoperative IH had a clinical recurrence during the follow-up. The ICV was significantly higher after the surgery (p < 0.0001), with an average increase of 3.2% (95% CI, 2.3-4.1%).

CONCLUSION

Reverse (RFC) is a useful technique for the correction of the frontal malformations related to craniosynostosis, such as a sloping forehead and/or a lack of the supraorbital projection. Regarding the limited gain of intracranial volume (ICV), it should not be used alone as primary cranial expansion surgery for craniosynostosis with intracranial hypertension (IH).

Addressing hypertelorism: Indications and techniques

From its first descriptions in the early 1920s to today's use of cutting guides via computer-assisted surgery, surgical techniques to address hypertelorism have progressed. The present article aims to provide historical background and an overview of the development of surgical techniques during the late 20th century and in recent years. First, a historical overview identifies the most important surgical advances leading to the present state of the art. Each major surgical innovation is described, to explain the changes in this surgical field, according to the type of approach. Then, a precise description of today's most recent practices is provided, with particular emphasis on the spectacular advances deriving from computer-assisted surgery. A thorough description of the use of cutting guides throughout the surgical phase is given.

Posterior fossa tumors in children: Radiological tips & tricks in the age of genomic tumor classification and advance MR technology

Imaging plays a major role in the comprehensive assessment of posterior fossa tumor in children (PFTC). The objective is to propose a global method relying on the combined analysis of radiological, clinical and epidemiological criteria, (taking into account the child's age and the topography of the lesion) in order to improve our histological approach in imaging, helping the management and approach for surgeons in providing information to the patients' parents. Infratentorial tumors are the most frequent in children, representing mainly medulloblastoma, pilocytic astrocytoma and brainstem glioma. Pre-surgical identification of the tumor type and its aggressiveness could be improved by the combined analysis of key imaging features with epidemiologic data.

Is It Safe To Use Frontofacial Monobloc Advancement and Cutting Guides on Adult Patients with Crouzon Syndrome? Introducing 2 Cases on 41- and 56-Year-Old Patients

BACKGROUND

Patients with Crouzon syndrome are mainly treated in childhood by frontofacial monobloc advancement to avoid ophthalmic, neurologic, and maxillary complications. There is no reported case of surgery on adult patients with Crouzon syndrome in the literature. However, when faced with 2 cases of adult patients showing severe quality of life deterioration, our team decided to make an attempt using monobloc advancement technique.

CASE DESCRIPTION

Two women aged 41 and 56 presented with untreated Crouzon syndrome and suffered from exorbitism, intracranial hypertension with chronic headaches, and hypoplastic maxillary. We decided to perform frontofacial monobloc advancement with internal distraction despite their advanced age using planned surgery and cutting guides. Distraction began 7-10 days after surgery and was of 15 mm. Distractors were taken off at 6 months. Surgical treatment corrected chronic headaches, ocular symptoms due to exorbitism, and hypoplastic maxillary. Patients were satisfied with the functional and aesthetic results. We noticed that this heavy surgery was more difficult to bear by these adults than children.

CONCLUSIONS

Adults with craniofacial malformations have a lower self-esteem, lower quality of life, and less satisfaction with their facial look as compared with individuals without facial malformations. There is also an increased risk of psychosocial problems. Despite postoperative difficulties and minor complications, our 2 patients were satisfied with the functional and aesthetic results. This led to the conclusion that surgically addressing adult patients with Crouzon syndrome via monobloc advancement is appropriate and secure when performed by a trained team.

Prenatal findings in carpenter syndrome and a novel mutation in RAB23

Carpenter syndrome is caused by mutations of the RAB23 gene. To date, 12 distinct mutations have been identified among 34 patients from 26 unrelated families. We report on the prenatal findings in a fetus with Carpenter syndrome with a novel RAB23 mutation. Cystic hygroma, bowed femora, abnormal skull shape and a complex heart defect were seen on ultrasound scan, and Carpenter syndrome was diagnosed at birth. Craniosynostosis and preaxial hexadactyly of the feet were retrospectively detectable on the fetal CT scan. Sequencing of RAB23 identified a homozygous mutation leading to skipping of exon 6 and premature termination codon (c.481G>C; p.Val161Leufs*16). This observation illustrates the difficulty of prenatal ultrasound diagnosis of Carpenter syndrome. To our knowledge, this diagnosis was suggested on ultrasound scan in only one prior patient, although in five other patients abnormal skull shape and variable findings, mainly limb anomalies including bowed femora in one case, were described during the pregnancy. Heart defect and bowed femora are rare postnatal findings. The diagnosis of Carpenter syndrome should therefore be considered on prenatal imaging in cases of bowed femora and/or cardiac defect associated with abnormal skull shape.

[Reduplication of an event after right caudate nucleus haemorrhage]

BACKGROUND

Environmental reduplication which is characterized by reduplication of places has been reported in right hemispheric lesions, particularly but not only in the right frontal region. However, spatial delirium may follow right sub-cortical lesions.

METHODS

We describe a 53 years-old man who had a reduplicative paramnesia for event alone after an intracerebral haematoma of the right caudate nucleus.

RESULTS

MRI Scan showed also an extension of the right caudate nucleus haemorrhage into the ventricular system. Regional cerebral blood flow studied with 99Tcm-HMPAO showed a decrease of perfusion in the right dorso-lateral frontal cortex. To our knowledge, we reported the first case of reduplicative paramnesia of event associated with a right caudate nucleus injury. Similar right frontal deactivation was observed in two cases of reduplicative paramnesia for place, one of them after an infarction of the retro-lenticular portion of the right internal capsulae, the other after a right thalamo-capsular haemorrhage.

CONCLUSION

We suggest that reduplicative paramnesia for event, like the previous cases reported of reduplicative paramnesia for place, may be linked to a subcortical lesion of the frontal lobe inducing a right functional frontal deactivation.

Papillary tumor of the pineal region in a child: case report and review of the literature

CASE REPORT

A 13-year-old boy presented with a history of intracranial hypertension. Radiologic studies revealed triventricular hydrocephalus secondary to a space-occupying lesion in the pineal region. Endoscopic third ventriculostomy was performed to treat hydrocephalus, and the lesion was biopsied. Complete resection of the tumor was subsequently performed. After a period of uncertainty, the diagnosis of papillary tumor of the pineal region was established. Tumor bed radiotherapy at a dose of 50 Gy was associated. With a follow-up of 15 months, the postoperative course was satisfactory with return to school and no residual tumor on magnetic resonance imaging.

CONCLUSION

Papillary tumors of the pineal region constitute a rare entity, with a difficult diagnosis, an uncertain prognosis, and a high risk of local recurrence; they must be treated by a combination of surgery and radiotherapy. The only identified prognostic factor is the complete or incomplete nature of surgical resection.

[Late diagnosis of Dandy-Walker syndrome revealed by gait disorders in an elderly]

The Dandy-Walker syndrome is a rare malformation usually diagnosed during pregnancy or early in the course of life. We report a case in an elderly hospitalised for gait disorders and recurrent falls. Cerebral MRI revealed hydrocephalus and posterior fossa cyst. The patient improved after ventriculocisternostomia.

Carcass and muscle characteristics of beef cull cows between 4 and 9 years of age

The effects of age and breed on carcass and muscle characteristics of cull cows slaughtered at the same fattening state between 4 and 9 years of age were analysed in four French breeds: Aubrac (AU), Charolais (CH), Limousin (LI), and Salers (SA). Muscle characteristics were determined in three muscles: longissimus thoracis (LT), semitendinosus (ST) and triceps brachii (TB). They included: (1) the % frequency, cross-sectional area and % area of the different fibre types classified according to their contraction rate and metabolic properties (slow twitch oxidative (SO), fast twitch oxidative glycolytic (FOG) and fast twitch glycolytic (FG)), (2) the isocitrate dehydrogenase (ICDH) and lactate dehydrogenase (LDH) activities, representative of oxidative and glycolytic metabolism respectively, and (3) the total and insoluble collagen contents. Whatever the age of the animals at slaughter, the same carcass composition, fibre characteristics (% frequency, area, % area) and metabolic enzyme activities were obtained whatever the muscles considered. In contrast, important differences between breeds were observed in carcass composition (muscle, fat, bone) and enzyme activities. CH cows presented the highest final live weight and LI carcasses were characterized by higher muscle weight, lower fat and bone weights and more glycolytic muscles. Among the muscle characteristics, collagen was the most influenced by age and breed in a breed and muscle dependent manner respectively. AU and LI cows exhibited lower total and insoluble collagen contents than CH and SA cows, particularly at 6 to 7 years of age and for the LT and ST muscles. Thus collagen could explain an important part of the variability in meat quality from cull cows. In conclusion, results of this study provide consistent data on muscle characteristics of cull cows, few studies were available until then.

Effects of age and breed of beef bulls on growth parameters, carcass and muscle characteristics

The effects of age and breed on growth parameters, carcass and muscle characteristics of bulls, slaughtered at 15, 19 and 24 months of age, were analysed in four French breeds: Aubrac (AU), Charolais (CH), Limousin (LI), and Salers (SA). Muscle characteristics were determined in three muscles: longissimus thoracis (LT), semitendinosus (ST) and triceps brachii (TB). They included: (1) the % frequency, cross-sectional area and % area of fibre types, which were classified according to the contractile nature of the fibres and their metabolic properties (SO slow oxidative, FOG fast oxidative glycolytic and FG fast glycolytic); (2) the isocitrate dehydrogenase (ICDH) and lactate dehydrogenase (LDH) activities, representative of oxidative and glycolytic metabolism respectively; and (3) the total and insoluble collagen contents.

In the four breeds, the average daily gain and the food efficiency decreased with age (P < 0·001). The carcass characteristics (muscle, fat and bone weights) increased with age (P < 0·001). The increase of muscle carcass weight with slaughter age was in parallel with the increase in cross-sectional area of individual muscle fibres. Oxidative fibre (SO and FOG) areas increased more between 15 and 24 months than glycolytic fibre (FG) area. Differences between muscles in increases in areas of muscle fibres were consistent: the increase was greater for TB than ST and LT. The muscles studied became more slow and more oxidative above 19 months of age, as evidenced by the fact that the SO % frequency (P < 0·001) and % area (P < 0·001) and ICDH activity (P < 0·05) increased, and LDH activity decreased (P < 0·01). Insoluble collagen content decreased between 15 and 19 months (P < 0·001), and both total (P < 0·01) and insoluble (P < 0·001) collagen contents increased from 19 months.

So carcass characteristics were modified between 15 and 24 months, and muscle characteristics were especially modified from 19 months of age. In addition, differences in slaughter data between breeds were clear and consistent, whereas those of muscle characteristics were few and not consistent.

Cbl-mediated ubiquitination of alpha5 integrin subunit mediates fibronectin-dependent osteoblast detachment and apoptosis induced by FGFR2 activation

Fibroblast growth factor receptor signaling is an important mechanism regulating osteoblast function. To gain an insight into the regulatory role of FGF receptor-2 (FGFR2) signaling in osteoblasts, we investigated integrin-mediated attachment and cell survival in human calvarial osteoblasts expressing activated FGFR2. FGFR2 activation reduced osteoblast attachment on fibronectin. This was associated with reduced expression of the alpha5 integrin subunit normally expressed in human calvarial osteoblasts in vivo. Treatment with lactacystin, a potent inhibitor of proteasome, restored alpha5 integrin levels in FGFR2 mutant osteoblasts. Immunoprecipitation analysis showed that alpha5 integrin interacts with both the E3 ubiquitin ligase Cbl and ubiquitin. Immunocytochemistry revealed that alpha5 integrin colocalizes with FGFR2 and Cbl at the leading edge in membrane ruffle regions. Transfection with the 70Z-Cbl mutant lacking the RING domain required for Cbl-ubiquitin interaction, or with the G306E Cbl mutant that abolishes the binding ability of Cbl phosphotyrosine-binding domain restored alpha5 integrin levels. This suggests that Cbl-mediated ubiquitination plays an essential role in alpha5 integrin proteasome degradation induced by FGFR2 activation. Reduced alpha5 integrin expression was associated with an increased Bax/Bcl-2 ratio and increased caspase-9 and -3 activities in FGFR2 mutant osteoblasts. Forced expression of alpha5 integrin rescued cell attachment and corrected both the Bax/Bcl-2 ratio and caspase-3 and caspase-9 activities in FGFR2 mutant osteoblasts. We show that Cbl recruitment induced by FGFR2 activation triggers alpha5 integrin degradation by the proteasome, which results in reduced osteoblast attachment on fibronectin and caspase-dependent apoptosis. This identifies a functional role of the alpha5 integrin subunit in the induction of apoptosis triggered by FGFR2 activation in osteoblasts, and reveals that a Cbl-dependent mechanism is involved in the coordinated regulation of cell apoptosis induced by alpha5 integrin degradation.

Effect of selection for improved body weight and composition on muscle and meat characteristics in Muscovy duck

1. For 25 years, the Muscovy duck has been selected for greater body weight at slaughter age, higher meat yield and lower fat content. The aim of this study was to analyse the effects of such selection on the biochemical and technological characteristics of duck meat. 2. A line which has been maintained without any selection since 1975 (control line) and a heavy line now commercialised (selected line) were reared under the same conditions. We compared growth performances, dressing and dissection yields and biochemical and technological characteristics of duck meat at 8, 10 and 12 weeks of age. 3. Our results showed that an indirect effect of selection was to increase the duck growth rate. At a given age, muscle weights and yields as well as carcase fat content were higher for selected ducks. In the selected line, muscle fibres were larger and the collagen content in muscles lower. 4. The Sartorius muscle in ducks from the selected line exhibited a higher percentage in numbers of white type IIb fibres to the detriment of red type IIa fibres. Its glycolytic enzyme activity was higher and its oxidative enzyme activity lower. 5. In breast muscle, selection decreased the rate of post-mortem decline in pH value, increased protein and mineral contents and decreased moisture. It did not affect fibre type, colour, haem pigment and lipid contents, collagen solubility or drip loss. 6. In conclusion, the effects of Muscovy duck selection on meat quality were relatively moderate.

Cauda equina tumors: a French multicenter retrospective review of 231 adult cases and review of the literature

Large series of cauda equina tumors in adults are seldom reported. This French series retrospectively reviews 231 cases collected for the congress of the Societe Francaise de Neurochirurgie in 1996. The authors first analyze this series and then discuss the pertinent literature. Schwannoma was the most frequent benign tumor in this series, followed by ependymoma. Very few malignant tumors were recorded; these were usually malignant neurinomas nearly always in neurofibromatosis patients. Some other rare tumors were also recorded, including paragangliomas. This series confirms the importance of the pretherapeutic neurological status in functional prognosis. All schwannomas can be cured, while ependymomas and paragangliomas may recur after a very long delay. Surgery must be as complete as possible, since adjuvant therapies are proven to have little efficacy. This type of tumor requires very long follow-up. Prognosis is good for hemangioblastomas. Sphincter dysfunctions carries a poor prognosis and may appear after primary surgery, more often after treatment of recurrences.

Age-related changes and location of types I, III, XII and XIV collagen during development of skeletal muscles from genetically different animals

The ontogenesis of total collagen and of different collagen types was studied in four muscle types from genetically different cattle. Hydroxyproline content was 1.2-fold higher in muscles from cross-bred foetuses with normal muscle growth compared to those of the other genetic types (pure bred with different growth rates, double-muscled breed). A similar tendency was observed for type III collagen content. In all muscles of each animal studied, type XII and XIV collagens were colocated in perimysium. Immunolabelling obtained for type XII collagen was higher during foetal life than after birth, while for type XIV collagen, the opposite result was obtained. Whatever the muscle studied, but especially in semitendinosus muscle, during the foetal and the post-natal period until 15 months of age, immunolabelling with antibody anti-type XIV collagen tended to be more intense in muscles of animals from fathers selected for a low muscle growth capacity compared to those from fathers selected for a high muscle growth capacity. In conclusion, this study shows, that during foetal life, selection according to muscle growth capacity has no significant effect on the contents of total hydroxyproline or type III collagen, but minor effects on collagen localization.

Characterisation and location of insulin-like-growth factor (IGF) receptors in the foetal bovine Semitendinosus muscle

We characterised IGFI and IGFII receptors and located them in bovine muscle during foetal growth. Semitendinosus muscle samples were taken from foetuses ranging from 80 to 270 days post-conception. The relative affinities of 125I-IGFII and 125I-IGFI mark the presence of typical type II and type I receptors in foetal muscle membranes. IGFII-specific binding is consistently five times greater than that of IGFI. The patterns of 125I-IGFII- and 125I-IGFI-specific binding are similar. They increase up to 110 and 170 days post-conception, respectively (P < 0.05); thereafter, they decrease (P < 0.05). This decrease was due to a fall in the number of receptors without any change in affinity. At the adult stage the specific binding of both the 125I-IGF is very low. In foetal muscle, type II receptors are located both in the muscle bundles and in the connective tissue while type I receptors are only located in the muscle bundles.

Age-related changes and location of type I, III, IV, V and VI collagens during development of four foetal skeletal muscles of double-muscled and normal bovine animals

The aim of this work was to study the variability in the quantities of hydroxyproline, of type I and III collagens and in the location of types, I, III, IV, V, VI in four muscles of normal and double-muscled (DM) cattle. Samples were collected from foetuses at different ages post-conception. Both in the two genetic types and in muscles, from 110 days, types I, III, V, VI were located in perymisium and types I, IV, V, VI in endomysium. The amounts of hydroxyproline and of type I collagen increased from 150 to 180 or 230 days then decreased up to 260 days, with a trend to lower quantities in muscles of DM animals. Depending on the muscle and of the genetic type, amounts of type III, or changed as those of type I, or remained stable. Whatever the genetic type, at the end of gestation, proportions of type I and III in the total collagen are not identical in the four muscles, differences between muscles being particularly marked for type III, CT and MA muscles being the richer in this type. In addition, these two muscles contained less type III in DM animals than in normal ones.

Insulin-like growth factor II (IGF-II) mRNA expression during skeletal muscle development of double-muscled and normal bovine foetuses

We investigated the IGF-II gene expression in developing Semitendinosus muscle in foetal normal and double-muscled cattle. Samples from normal and double-muscled foetuses ranging from 90 to 210 d post-conception were collected and total RNA extracted. Northern blot analysis was performed using the human IGF-II cDNA probe. Five IGF-II transcripts, 5.1, 4.4, 3.7, 2.6 and 1.7 kb, were detected in muscle samples. Throughout gestation, all transcripts, except for the 5.1 kb one, decreased similarly in both genetic types. In double-muscled foetuses, the amount of the 5.1 kb transcript was higher than those of the other transcripts and its expression remained stable throughout the gestational stages analysed. These results indicated that the regulation of IGF-II gene transcription was distinct in both genetic types. The IGF-II foetal plasma concentrations increased throughout gestation. In bovine foetuses, the first muscle cell differentiation was concomitant with a high autocrine IGF-II mRNA expression and low plasma IGF-II levels in both genetic types. The second step of muscle cell differentiation was associated with high IGF-II plasma concentrations and the autocrine expression of IGF-II was reduced.

Age-related changes and location of type I, III and IV collagens during skeletal muscle development of double-muscled and normal bovine foetuses

The aim of this study was to investigate age-related changes in collagen content in muscles of normal and double-muscled (DM) bovine foetuses. Psoas major (PM) and triceps brachii (TB) muscles were collected from foetuses at 110 to 260 days post-conception (p.c.), frozen and powdered. Cyanogen bromide (CNBr) digestion and hydroxyproline measurements were carried out on the powder. CNBr peptides underwent SDS-polyacrylamide gel electrophoresis, and type I and III collagen relative variations were measured by densitometric analysis. Type I and III procollagen mRNA were located by in situ hybridization and types I, III and IV collagen located by indirect immunofluorescence. Although there was no significant difference between normal and DM animals in the amounts of collagen (except in PM muscle at 180 and 230 days p.c.), there was nevertheless a tendency to lower collagen content in muscles of DM animals. Amounts of hydroxyproline in PM and TB muscles from 110 to 230 days p.c. increased two- and threefold to 8.5 micrograms per mg of dry matter (d.m.) and 12 micrograms per mg d.m., respectively, and then decreased up to 260 days p.c., when they were twice as high in TB muscle (9.1 micrograms per mg d.m.) as in PM (4.5 micrograms per mg d.m.). The same difference in hydroxyproline levels was observed between normal adult PM and TB muscles. These variations were explained, mainly, by those of type I. In foetal muscle, in both genotypes and as in adult muscle, perimysium was types I and III, and endomysium type I, III and IV. Procollagen type I and III mRNA were located in perimysium. In conclusion, this study emphasizes that at the end of foetal life, collagen content is representative of what it will be in adult in muscle of both normal and DM animals.

In situ localization of muscle insulin-like growth factor-II mRNA in developing bovine fetuses

Insulin-like growth factor-II (IGF-II) modulates myogenesis in muscle cell cultures, in utero. IGF-II gene expression is developmentally regulated in several tissues including muscle. Determining whether IGF-II is expressed by developing muscle cells or by neighbouring cells in developing muscle tissue is crucial for determining whether IGF-II exerts a paracrine or an autocrine affect on myogenesis. Semitendinosus muscle samples from 12 bovine fetuses ranging from 60 to 274 days post conception (pc) were analysed for the amount and localization of muscle IGF-II mRNA using Northern, dot blot and in situ hybridization analyses. Northern blot analysis revealed multiple IGF-II transcripts of 5.1, 3.7, 2.6, 2.0, 1.7 and 1.1 kb in developing bovine muscle tissue. The relative amount of muscle IGF-II mRNA increased (P < 0.05) until 162 days pc, then decreased (P < 0.01) to near undetectable levels by the end of gestation (approximately 284 days pc). Between 60 and 162 days pc, in situ hybridization revealed that the majority of the IGF-II transcripts were localized to developing muscle cells rather than connective tissue. After 162 days pc the IGF-II hybridization signal shifted away from muscle cells and greater accumulation was observed in the connective tissue at 274 days pc. These data confirm that the expression of IGF-II in developing bovine muscle tissue is primarily localized in muscle cells and support the claim that IGF-II acts as an autocrine-acting growth factor during myogenesis in vivo.

Developmental regulation of bovine insulin-like growth factor-II (IGF-II) gene expression: homology between bovine transcripts and human IGF-II exons

Initial observations have indicated similarities between bovine and human IGF-II production during development. The aim of the present study was to investigate whether cattle could provide an experimental model that would mimic the complex pattern of human IGF-II gene expression. Expression of bovine IGF-II gene during development was studied by RNA hybridization using various human IGF-II probes. In fetal tissues and in adult muscle, the bovine IGF-II gene was expressed as a family of eight transcripts ranging in size from 5.2 to 1.1 kb. In adult bovine liver, a major IGF-II transcript of 4.4 kb was expressed that could not be detected in any fetal or adult extra-hepatic tissue. During fetal life, quantitative IGF-II mRNA expression differed in liver and muscle, and the relative amounts of the different transcripts varied with the tissue of origin. These observations suggest that the regulation of bovine IGF-II gene expression is specific to the stage of development and the tissue concerned. Moreover its pattern is very similar to that in its human counterpart. In order to identify a putative homology between human and bovine gene structures, bovine mRNAs were examined for cross-hybridization with various non-coding exons of the human gene. Cross-hybridization was detected with human untranslated exons 5 and 6, suggesting the presence of two distinct promoters similar to the human promoters P3 and P4. The 4.4 kb mRNA species expressed in adult bovine liver failed to hybridize to a probe for human exons 1 and 2, suggesting that the leader sequences of this transcript were different from those present in the human gene. Finally, results obtained with a probe containing the 3' untranslated end of exon 9 suggested the presence of at least two polyadenylation sites in the bovine gene. Although differences in IGF-II gene structures were found between cattle and man, the similarities in the pattern of gene expression between the two species suggest that cattle may be a useful model to investigate some developmental aspects of the expression of the human IGF-II gene.

Myosin expression in semitendinosus muscle during fetal development of cattle: immunocytochemical and electrophoretic analyses

The pattern of expression of different types of myosin and the development of different muscle cell populations were studied in the semitendinosus muscle of cattle from 39 d of gestation to 30 d of post-natal life. Monoclonal antibodies specific to different myosin heavy chains were used. Two cell generations were identified during myogenesis. They appeared successively and were characterized by different patterns of expression of myosins. The first population, which was present from the first stage studied (39 d of gestation), gave rise to type I fibers, which, in the mature animal, express only slow myosin. A second generation became differentiated at about 120 d of fetal life and then developed into type II fibers (IIa, IIb or IIc). The beginning of differentiation was characterized in all the cell populations by the expression of specific types of embryonic or fetal myosins. A comparison of these results with findings from previous works shows a marked similarity between species in the pattern of myogenesis but great differences in the length of the different stages of development. In this respect, myogenesis in cattle closely resembles that in man.

Cimaterol reduces cathepsin activities but has no anabolic effect in cultured myotubes

The effect of the beta-adrenergic agonist cimaterol on bovine and chicken primary myotubes was assessed. Cimaterol at 10-100 nM concentrations reduced cathepsin B benzyloxy-carbonyl-Arg-Arg-4-methyl-7-coumarylamide hydrolyzing activity, as well as benzyloxycarbonyl-Phe-Arg-4-methyl-7-coumarylamide hydrolysis, which is a substrate for both cathepsin B and cathepsin L. Maximum effect was observed after 6-16 h treatment. Cathepsin H Arg-4-methyl-7-coumarylamide hydrolyzing activity was low and not significantly affected by cimaterol treatment. Despite decreasing cathepsin activities, cimaterol also increased proteolysis rates but induced no detectable effect on protein synthesis rates. These observations suggest that beta-agonists, as a result of a direct action on muscle, can decrease cathepsin activities but that beta-agonist-induced muscle hypertrophy may not be due to a direct effect on muscle cells.