The chicken leptin gene: has it been cloned?

The DNA sequence of a chicken leptin gene that shares 95% nucleotide similarity with the mouse leptin sequence has been recently reported (Taouis et al., 1998, Gene 208, 239-242). Experiments have been performed independently in two laboratories to try to confirm this finding. Fourteen PCR primers based on the mouse leptin sequence were designed to amplify the avian leptin gene. Four of the primers were identical to the mouse and published chicken leptin sequences. PCR amplification was carried out on genomic DNA and reverse-transcribed mRNA from the fat, liver, and pancreas of several chicken strains and from the domestic turkey, goose, and Japanese quail. No PCR products sharing close similarity to the mouse leptin sequence were generated from any avian templates. Amplification of mouse leptin sequence was consistently obtained when control mouse templates were used. Northern hybridization using a mouse leptin probe failed to produce a signal with poly(A)+ RNA from chicken fat and liver and from the fat and liver of force-fed geese but a strong signal was obtained from control mouse fat total RNA. Southern hybridization under low stringency washing conditions revealed hybridization of a mouse leptin probe to chicken genomic DNA. Under higher stringency washing conditions, the chicken signal disappeared, while those from control mouse and sheep genomic DNA remained. This suggests that the putative chicken leptin sequence shares less than the 83% nucleotide sequence identity between the mouse and sheep genes. It is concluded that a chicken leptin gene sequence with close sequence similarity to mouse leptin is not present in the chicken genome. Furthermore, mRNA sharing high sequence identity with mouse leptin is not present in the fat or liver of the domestic chicken, turkey, goose, or Japanese quail.

Hepatic iron overload: quantitative MR imaging

Iron deposits demonstrate characteristically shortened T2 relaxation times. Several previously published studies reported poor correlation between the in vivo hepatic 1/T2 measurements made by means of midfield magnetic resonance (MR) units and the hepatic iron content of iron-overloaded patients. In this study, the authors assessed the use of in vivo 1/T2 measurements obtained by means of MR imaging at 0.5 T using short echo times (13.4 and 30 msec) and single-echo-sequences as well as computed tomographic (CT) attenuation as a measure of liver iron concentration in 10 severely iron-overloaded patients with beta-thalassemia major. The iron concentrations in surgical wedge biopsy samples of the liver, which varied between 3 and 9 mg/g of wet weight (normal, less than or equal to 0.5 mg/g), correlated well (r = .93, P less than or equal to .0001) with the preoperative in vivo hepatic 1/T2 measurements. The CT attenuation did not correlate with liver iron concentration. Quantitative MR imaging is a readily available noninvasive method for the assessment of hepatic iron concentration in iron-overloaded patients, reducing the need for needle biopsies of the liver.

Molecular cloning and properties of the chicken leptin-receptor (CLEPR) gene

The mammalian leptin receptor (LEPR) (formerly OB-R) mediates the weight regulatory effects of the circulating hormone leptin. The extreme obese phenotype of recessive mutations in the mouse leptin or LEPR genes (ob/ob and db/db mice, respectively) indicate the high potential of these genes for medical and agricultural research. In this paper, we report on the cloning of the full-length chicken leptin receptor (CLEPR) cDNA, which is the first non-mammalian cloning of a LEPR gene. The CLEPR gene shares a relatively low sequence similarity with its mammalian counterparts, with an average of 60% identical nucleotides. However, comparison between the predicted protein sequences has shown a tight conservation of most previously characterized LEPR motifs and essential tyrosine residues. Similarities between the chicken and the mammalian LEPR genes were also observed in the pattern of mRNA expression. The identification of the CLEPR gene should facilitate the study of the molecular mechanism involved in the regulation of body growth and composition in avian.

New insight into calcinosis of juvenile dermatomyositis: a study of composition and treatment

Milk of calcium developed in 2 children with juvenile dermatomyositis. The fluid of the collection contained macrophages, interleukin-6, IL-1, and tumor necrosis factor. The patient who had dystrophic calcinosis had a dramatic improvement with the introduction of alendronate. These findings suggest that calcinosis of juvenile dermatomyositis may be mediated by activated macrophages and that alendronate can be an effective treatment for this condition.

Effect of acquisition of improved thermotolerance on the induction of heat shock proteins in broiler chickens

The role of heat shock proteins (HSP) in the protection of cells from heat stress is well established. However, very little is known about their contribution to thermotolerance in the complexity of a whole homeotherm animal. Here we report on the analysis of protein synthesis in lung and heart muscle tissues of broiler chickens following exposure to high ambient temperature. Half of the flock was treated by an early age exposure to heat (conditioning), to improve thermotolerance. In contrast to what has been expected, lower levels of HSP induction was observed in the treated chickens. We suggest that 1) the induction of HSP in the heart and lung tissues of the whole animal correlates with the body temperature and 2) HSP response does not represent a part of the long-term mechanism that is evoked by the early age conditioning.

Inflammatory pseudotumor in childhood. A diagnostic and therapeutic dilemma

We describe a case of inflammatory pseudotumor of the lower abdomen in a young child. The urinary bladder and abdominal wall were involved, and the pseudotumor simulated a malignant sarcomatous tumor. Surgical excision was undertaken, and the outcome was favorable. This rare tumor simulates a true neoplasm both clinically and morphologically and presents a diagnostic and therapeutic dilemma. Our case and a review of the literature indicate that an effort should be made to perform a radical excision. This is considered the treatment of choice except if it requires a mutilating procedure.

Pediatric brain stem gliomas: an update

It has become evident that pediatric brain stem gliomas are a heterogeneous pathology and should be classified according to clinical and radiological criteria. This classification has contributed to better treatment and greatly improved prognosis. Based on a review of the literature, we describe the different types of brain stem astrocytomas reported, which are: cervicomedullary, exophytic, cystic, focal and diffuse. Particular attention is paid to therapeutic modalities. For the first three lesions named the treatment is surgical and oncological therapy should be evaluated only for regrowth of the mass. Focal tumors of the medulla and pons are still treated empirically (surgically and/or with radiotherapy), because a definitive therapeutic protocol has not yet been elaborated; on the other hand it is well established that if the focal mass is in the midbrain this should merely be monitored by means of serial MRI, while radiotherapy should be applied in the event of the tumor's growth. Diffuse gliomas are treated with oncological therapy, and surgery (for biopsy or tumor excision) is not indicated. Five illustrative cases from our department are presented.

The root meristem is shaped by brassinosteroid control of cell geometry

Growth extent and direction determine cell and whole-organ architecture. How they are spatio-temporally modulated to control size and shape is not well known. Here we tackled this question by studying the effect of brassinosteroid (BR) signalling on the structure of the root meristem. Quantification of the three-dimensional geometry of thousands of individual meristematic cells across different tissue types showed that the modulation of BR signalling yields distinct changes in growth rate and anisotropy, which affects the time that cells spend in the meristem and has a strong impact on the final root form. By contrast, the hormone effect on cell volume was minor, establishing cell volume as invariant to the effect of BR. Thus, BR has the highest effect on cell shape and growth anisotropy, regulating the overall longitudinal and radial growth of the meristem, while maintaining a coherent distribution of cell sizes. Moving from single-cell quantification to the whole organ, we developed a computational model of radial growth. The simulation demonstrates how differential BR-regulated growth between the inner and outer tissues shapes the meristem and thus explains the non-intuitive outcomes of tissue-specific perturbation of BR signalling. The combined experimental data and simulation suggest that the inner and outer tissues have distinct but coordinated roles in growth regulation.

Central precocious puberty: evaluation by neuroimaging

To evaluate the incidence of abnormal intracranial findings in children with central precocious puberty, 62 children (51 girls, 11 boys) were examined by computerized tomography and/or magnetic resonance imaging (MRI) of the brain. Forty-four had normal examinations; 18 (11 girls, 7 boys) showed intracranial pathologies, including hamartoma of the tuber cinereum (8 cases), parenchymal loss (3 cases), hypothalamic-chiasmatic lesions (2 cases), lesions of the corpus callosum (2 cases), suprasellar cyst (1 case), and pineal cyst and mesiotemporal sclerosis (1 case each). Based on the correlation between the clinical and the imaging results of this series, the authors recommend MRI as the imaging method of choice in the investigation of precocious puberty.

Visual pathway glioma: an erratic tumour with therapeutic dilemmas

OBJECTIVE

Our experience in children with visual pathway glioma (VPG) was reviewed to delineate its clinical characteristics.

DESIGN

The charts and imaging studies of 21 children with VPG who were followed up in our centre during the last 12 years were reviewed and summarised.

RESULTS

VPG accounted for 13.1% of all brain tumours treated during this period. Sixty two per cent of the children with VPG had neurofibromatosis type 1 (NF-1). Among these, more than 60% were detected as part of routine work up. In some cases decreasing visual function preceded the appearance of the VPG on imaging studies. Tumour growth rate was markedly unpredictable. All treatment modalities employed led to tumour shrinkage and stabilisation for a variable period, but none was successful in totally eradicating the tumour. Complications were less severe after chemotherapy compared with radiotherapy. Three children died, none with NF-1, with a globular hypothalamic/chiasmatic tumour and accompanying electrolyte abnormalities.

CONCLUSIONS

NF-1 is a favourable prognostic marker for VPG. Whenever possible a period of observation is necessary before treatment is initiated, during which time tumour size and visual function should be closely followed up; an untoward change in either of these is an indication for the start of treatment, preferably chemotherapy first. The combination of a globular hypothalamic/chiasmatic glioma and electrolyte abnormalities in a child without NF-1 are related to a poor prognosis.

The enigma of stress fractures in the pediatric age: clarification or confusion through the new imaging modalities

Cortical thickening and/or periosteal reaction in long bones of children and adolescents continue to present a diagnostic difficulty for the pediatric radiologist. A history of physical activity points to the possibility of stress fracture, nevertheless bone malignancy or chronic inflammatory changes have to be excluded. The MRI findings in recent cases of stress fractures were confusing. An extensive metadiaphyseal abnormal signal from the medullary cavity was observed. Only the meticulous correlation between the various imaging modalities established the correct diagnosis. Stress fractures can occur in a normal bone that is subjected to repeated trauma, with the strain being less than that which causes an acute fracture. Localized pain is the presenting symptom. This kind of fracture is encountered in adolescents who are often involved in competitive physical exercise. The conventional radiographic examination shows the evidence of the fracture repair rather than the fracture itself: localized periosteal reaction and endosteal thickening. A radiolucent cortical fracture-line is usually not demonstrated. The radiologic appearance can be problematic in the pediatric age and necessitates differentiation from osteomyelitis or bone malignancy. The diagnostic investigation includes multidirectional bone radiographs. Tcm99 polyphosphate bone scintigraphy and computerized tomography. Recently MRI has been added to the diagnostic armamentarium. This paper presents the experience gained in the diagnosis of pediatric stress fractures which were investigated and followed up by MRI. It was found that this modality did not contribute to the establishment of the final diagnosis of stress fracture.

Iron overload following bone marrow transplantation in children: MR findings

OBJECTIVE

The purpose of this study was to determine the incidence of post-transfusional iron overload in children after bone marrow transplantation by reviewing their magnetic resonance imaging (MR) findings.

MATERIALS AND METHODS

We reviewed the abdominal MR studies of 13 children after autologous bone marrow transplantation. Nine of the children had also undergone MR prior to transplantation. Iron deposition in the liver, spleen and bone marrow was graded semi-quantitatively on both T1- and T2-weighted images. Serum ferritin levels and number of blood units given after bone marrow transplantation were recorded.

RESULTS

None of the pre-transplantation MR studies revealed iron overload. After bone marrow transplantation, three children showed normal liver and spleen. Iron overload in the liver was noted in ten patients (77 %), six of whom also showed iron overload in the spleen (46 %) and five in the bone marrow (38.5 %). The degree of hepatic iron overload was correlated significantly and splenic iron overload was correlated weakly with the number of blood transfusions (P = 0.01 and P > 0.01, respectively), but neither was correlated with the serum ferritin level.

CONCLUSION

Iron overload commonly accompanies bone marrow transplantation. The observed pattern of iron deposition, in which the spleen was uninvolved in 40 % of patients demonstrating iron overload, is not typical of post-transfusional hemochromatosis.

Estimating wall guidance and attraction in mouse free locomotor behavior

In this study, we estimate the influence exerted by the wall of the Open Field on the trajectory of the mouse. The wall exerts two types of influence on the mouse's path: one of guidance and one of attraction. The guiding influence is expressed by the tendency of mice to progress in parallel to the wall. This tendency wanes with increasing distance from the wall but is observed at large distances from it. The more parallel the mouse is to the wall the higher is its speed, even when distant from the wall. This association between heading direction and speed shows that the mouse controls its heading in reference to the wall. It is also observed in some blind strains, revealing that wall-guidance is not based exclusively on vision. The attraction influence is reflected by movement along the wall and by the asymmetry between speed during movement toward, and during movement away from the wall: sighted mice move faster toward the wall, whereas blind mice use similar speeds in both directions. Measures characterizing these influences are presented for five inbred strains, revealing heritable components that are replicable across laboratories. The revealed structure can lead to the identification of distinct groups of genes that mediate the distinct influences of guidance and attraction exerted by the wall. It can also serve as a framework for the decoding of electrophysiological data recorded in free moving rodents in the Open Field.

The natural history of osteonecrosis of the femoral head in children and adolescents who have Gaucher disease

We reviewed the cases of eight patients (thirteen hips) with Gaucher disease who had had osteonecrosis of the femoral head and had been managed with bed rest and non-weight-bearing with crutches only in the symptomatic stage of the bone crisis. The mean age of the patients at the onset of the first crisis in each hip was ten years (range, six to fourteen years). The mean age at the most recent follow-up examination for the six living patients (ten hips) was twenty-three years (range, nineteen to thirty-three years). The Mose rating was good for one hip, fair for two, and poor for seven. Despite the over-all unfavorable radiographic ratings, the six patients were asymptomatic and did not need assistance with daily activities. There is no known treatment that effectively prevents the development of deformities of the femoral head. Thus, we recommend symptomatic management for osteonecrosis of the femoral head in Gaucher disease with bed rest and analgesics followed by non-weight-bearing on the involved limb, if it makes the patient more comfortable, during the symptomatic stage of bone crisis.

Albright hereditary osteodystrophy with hypothyroidism, normocalcemia, and normal Gs protein activity: a family presenting with congenital osteoma cutis

The syndrome of Albright hereditary osteodystrophy (AHO), pseudohypoparathyroidism (PHP) and pseudopseudohypoparathyroidism (PPHP) is clinically and genetically heterogeneous. Classically, patients with PHP have the skeletal features of AHO, resistance to multiple hormones that work via cAMP such as parathyroid hormone and thyroid stimulating hormone, and deficient activity of Gs protein, the guanine nucleotide-binding protein that stimulates adenylate cyclase. However, patients without hormone resistance but with AHO and Gs deficiency were described (PPHP), as well as patients with multiple hormone resistance but without AHO or Gs deficiency. In a few patients with deficient Gs activity, hypothyroidism rather than hypocalcemia was the initial presentation of the disorder. We describe here a new variant of the syndrome, affecting 5 individuals in a 3 generation family with AHO, normal Gs activity and hypothyroidism. In the first 2 generations, mild features of AHO were present. The 2 sibs in the third generation had severe manifestations of AHO, including mild mental retardation as well as hypothyroidism. Diagnosis of congenital osteoma cutis at birth of the proband led to the diagnosis of the family. Elucidation of the molecular defect will shed light on the relationship between hormone resistance and AHO, as well as on the physiological mechanism of hormonal signal transduction.

Spinal involvement in children and adolescents with Gaucher disease

Nineteen patients with type I Gaucher disease with spinal involvement first diagnosed during childhood, were followed for 2 to 24 years (average 9 years), and their clinical and radiologic history reviewed. Patients presented with three types of pain: mild pain that was defined as nonspecific, severe pain due to bone crisis, and pain associated with vertebral collapse. Collapse of vertebra occurred gradually anywhere along the thoraco-lumbar spine, and usually more than one vertebra was involved. In three patients, rectangular collapse was noted. Six patients suffered from central vertebra collapse, and two from anterior wedge compression. Further vertebral collapse with signs of root and cord compression developed in three patients as they grew. Awareness to the possibility of progressive vertebral collapse and periodic follow-up might prevent severe complications.

Craniofacial and brain abnormalities in Laron syndrome (primary growth hormone insensitivity)

OBJECTIVE

To investigate abnormalities in the craniofacial structures and in the brain in patients with Laron syndrome.

DESIGN

Eleven patients with classical Laron syndrome, nine untreated adults aged 36-68 years and two children aged 4 and 9 years (the latter treated by IGF-I), were studied.

METHODS

Magnetic resonance images of the brain were obtained in all the patients. One patient also underwent computed tomography. The maximal diameter of the maxillary and frontal sinuses was measured and compared with reference values, the size of the sphenoid sinus was evaluated in relation to the sella, and the mastoids were evaluated qualitatively (small or normal). The brain was evaluated for congenital anomalies and parenchymal lesions.

RESULTS

In the adult untreated patients, the paranasal sinuses and mastoids were small; in six patients, the bone marrow in the base of the skull was not mature. The diploe of the calvaria was thin. On computed tomography in one adult patient, the sutures were still open. A minimal or mild degree of diffuse brain parenchymal loss was seen in ten patients. One patient demonstrated a lacunar infarct and another periventricular high signals on T2-weighted images. Two patients had cerebellar atrophy.

CONCLUSIONS

The present study has demonstrated the important role IGF-I plays in the development of the brain and bony structures of the cranium.

Hemorrhage associated with "bone crisis" in Gaucher's disease identified by magnetic resonance imaging

Children suffering from Gaucher's disease were examined by magnetic resonance imaging (MRI) during a characteristic episode of "bone crisis". An unexpectedly high intramedullary as well as subperiosteal signal was observed on both the T1- and T2-weighted sequences in 5 patients, suggesting a subacute hemorrhage or hematoma. It is conceivable that such a painful hemorrhage is an important component of the "bone crisis" phenomenon. Furthermore, in these cases this is a specific sign which may enable differentiation of bone crises from other types of bone pain associated with Gaucher's disease.

Low-dose high-frequency enzyme replacement therapy prevents fractures without complete suppression of painful bone crises in patients with severe juvenile onset type I Gaucher disease

Patients with type I Gaucher disease often present as adults with a mild disease and with less severe genetic mutations, especially 1226G/1226G (N370S/N370S). Patients presenting as children have an excess of compound heterozygotes of N370S and other mutations, such as 84GG, 1448C (L444P) and IVS2 + 1 in whom bone disease is common. We report our experience with low-dose high-frequency enzyme replacement therapy in such severely affected children. Ten patients (with severe juvenile onset type I Gaucher disease) were treated. Alglucerase (Ceredase) was infused at 30 units/kg/month in 13 fractions/month for more than one year. Bone disease was used as the main criterion for evaluating treatment results. No fractures occurred in spite of the fact that bone crises occurred in four patients after 12 to 24 months of treatment, in two during the third year, and in one during the fifth year. Nonosseous manifestations improved with treatment. The ability of low-dose high frequency alglucerase to prevent fractures in the presence of continuing bone crises was demonstrated.

Magnetic resonance imaging in the diagnosis of childhood discitis

Diagnosis of disc space infection in childhood is often delayed and is usually made on the basis of multiple roentgenographic, laboratory, and nuclear imaging studies. Four cases of septic discitis in children are described. Special emphasis is placed on the diagnostic findings with magnetic resonance imaging. Magnetic resonance sensitivity for this entity and its role in comparison with other imaging modalities are discussed.

Lung perfusion scans in patients with congenital heart defects

In 63 patients with various congenital heart defects, lung perfusion was evaluated with technetium-99mm macroaggregated albumin. Right lung perfusion abnormalities were documented in 34 patients (54%). A particularly high incidence occurred in patients who had undergone a systemic to pulmonary artery shunt operation as an initial palliative procedure or who had had right ventricular outflow reconstruction and in those with bilateral pulmonary artery stenosis. Serial studies were helpful in evaluating the functional results of different transcatheter interventions for optimizing pulmonary blood flow. The quantitative relative perfusion radionuclide method was a more sensitive means of detecting cases of abnormal lung perfusion than was chest radiology.

Acute diaphragmatic paralysis caused by chest-tube trauma to phrenic nerve

A 3 1/2-year-old child developed unilateral diaphragmatic paralysis after chest drain insertion. Plain chest X-ray demonstrated paravertebral positioning of the chest-tube tip, and magnetic resonance imaging revealed hematomas in the region of the chest-tube tip and the phrenic nerve fibers. The trauma to the phrenic nerve was apparently secondary to malposition of the chest tube. This is a rare complication and has been reported mainly in neonates. Radiologists should notify the treating physicians that the correct position of a chest drain tip is at least 2 cm distant from the vertebrae.

Preoperative localization of a foreign body by magnetic resonance imaging

Nonradioopaque foreign bodies are very difficult to detect and localize. A case is presented in which a retained palm tree thorn was visualized and extracted with the help of magnetic resonance imaging.

Induction of thermotolerance in chickens by temperature conditioning: heat shock protein expression

Broiler chicks were conditioned by exposure to heat stress early in life to elucidate physiological mechanisms and possible involvement of the known heat shock proteins (HSPs) in the induction of thermotolerance. Chicks were exposed to 36 +/- 1 degree C; 70-80% relative humidity (rh) for 24 hours at the age of 5 days. During conditioning, weight gain was depressed. Due to accelerated growth during the postconditioning period, a complete compensation for lost weight gain was achieved by the conditioned group. At the age of 42 days, challenge with acute heat stress of 35 +/- 1 degree C; 25-30% rh resulted in a large increase in cloacal temperature of the control chickens and by a more moderate increase in the conditioned chickens. Mortality during the thermal challenge was significantly higher in the control chickens than in the conditioned ones. Conditioning at an early age resulted in reduced plasma triiodothyronine (T3) concentration and hemodynamic changes (significant decrease in heart weight and hematocrit). The synthesis rate of 70 and 90 kDa HSPs during the first hour of heat challenge, accelerated gradually in control chickens, whereas in the conditioned chickens it accelerated only after 3 hours and in a more moderate response. These results suggest that HSP's response does not play a major role in the conditioning-induced mechanism leading to acquisition of thermotolerance in chickens.

Effect of P-glycoprotein expression on outcome in the Ewing family of tumors

This study was designed to determine the prognostic significance of multidrug resistance, mediated by P-glycoprotein (Pgp) expression, in Ewing sarcoma. The clinical and laboratory features, treatment protocol, and outcome of 75 patients with Ewing sarcoma or peripheral neuroectodermal tumor treated between 1972 and 1997 were reviewed. Pgp expression was tested with the monoclonal antibody JSB-1. Thirty-four (64%) of the 53 tissue samples from untreated patients stained positive for Pgp. Progression-free and overall survival were 44 and 59%, respectively, in patients with negative findings, and 28 and 41% in those with positive findings; neither difference was significant. Of the 12 relapsed patients, 6 (50%) expressed more Pgp after chemotherapy than at diagnosis and 4 (33%) expressed less. Within these subgroups, 5 out of 6 and 3 out of 4 died from the disease. No correlation was found between Pgp and known prognostic factors of Ewing tumors. Pgp expression is probably an intrinsic factor of Ewing tumors but has no correlation to prognosis.