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Biomedical subjects

G Horev

Publications and source records attributed to G Horev.

At least 19 recordsLinked to original sources
PubMed2007

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.

Animals↗
PubMed2002

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.

Adult↗
PubMed2001

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.

Acute Disease↗
PubMed2001

Intracranial cavernous hemangioma in a neonate.

Cogenital intracranial hemangioma is rare, and the imaging findings have been described in very few cases. We describe a case of a huge congenital left parietal hemangioma that was diagnosed postnatally by head duplex ultrasonography. Complete surgical resection yielded an excellent outcome.

Brain Neoplasms↗
PubMed2001

Significance of residual abdominal masses in children with abdominal Burkitt's lymphoma.

PURPOSE: To evaluate the natural history of children with abdominal Burkitt's lymphoma who had complete clinical remission and residual abdominal mass after treatment. MATERIAL AND METHODS: The charts and imaging findings of all children with abdominal Burkitt's lymphoma treated and followed at our medical center between 1988 and 1999 were reviewed for the presence, management, clinical course, and prognosis of residual mass. RESULTS: Only children who achieved complete clinical remission were included. The study group consisted of 33 children (20 boys and 13 girls) aged 2.6-17.6 years (mean 7.2 years). Of these, seven (20.6 %) were found to have a residual abdominal mass. Two underwent second-look operation with no evidence of viable tumor on histology. The remaining five were followed by imaging studies for 2.2-9.1 years (mean 6.1 years); none relapsed. CONCLUSION: Residual mass is not uncommon in children with abdominal Burkitt's lymphoma. The presence of residual mass in a child with complete clinical remission does not alter the long-term prognosis. Therefore, in children with Burkitt's lymphoma and residual mass with no other signs of disease activity, expectant watching may be appropriate.

Abdominal Neoplasms↗
PubMed2001

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.

Adolescent↗
PubMed2000

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.

Alternative Splicing↗
PubMed2000

Tc-99m MIBI to evaluate children with Ewing's sarcoma.

PURPOSE: Tc-99m MIBI has been used increasingly to evaluate benign and malignant tumors because of its tumor-seeking properties and ability to provide an imaging assessment of multiple-drug resistance. This study investigated the clinical utility of Tc-99m MIBI in the management of Ewing's sarcoma in children. METHODS: Thirteen Tc-99m MIBI studies in nine (six male, three female) patients ages 6.5 to 20 years (mean, 13.4 years) with Ewing's sarcoma were reviewed. All patients had imaging studies at diagnosis, and four had follow-up studies during or after therapy. Scintigraphy was evaluated for Tc-99m MIBI uptake within the tumor and in metastases, which other imaging modalities had shown to be present in four patients. Scintigraphic results were correlated with the clinical course in all patients and with tumor P-glycoprotein status in six patients. RESULTS: Tc-99m MIBI accumulated in 6 of 9 primary tumors and did not accumulate in one recurrent tumor. No metastases showed Tc-99m MIBI uptake. The presence or absence of Tc-99m MIBI uptake at diagnosis or after therapy carried no prognostic significance. Tc-99m MIBI was present in the two tumors that were P-glycoprotein positive and in only one of four tumors that were P-glycoprotein negative. CONCLUSION: Tc-99m MIBI imaging does not appear to be useful in Ewing's sarcoma.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

Traumatic adrenal injury in children.

BACKGROUND: Multiple organ injury in children is an increasingly frequent phenomenon in the modern emergency room. Adrenal hemorrhage associated with this type of trauma has received little attention in the past. OBJECTIVES: Using computed tomography, we sought to determine the rate and nature of adrenal gland injury in children following blunt abdominal trauma due to motor vehicular accident. METHODS: A total of 121 children with blunt abdominal trauma were examined and total body CT was performed in cases of multi-organ trauma or severe neurological injury. RESULTS: Of all the children who presented with blunt abdominal trauma over a 51 month period, 6 (4.95%) had adrenal hemorrhage. In all cases only the right adrenal gland was affected. Coincidental injury to the chest and other abdominal organs was noted in 66.7% and 50% of patients, respectively. CONCLUSIONS: Traumatic adrenal injury in the pediatric population may be more common than previously suspected. Widespread application of the more sophisticated imaging modalities available today will improve the detection of damage to the smaller organs in major collision injuries and will help in directing attention to the mechanism of trauma.

Abdominal Injuries↗
PubMed2000

Osteoid osteoma: resection with CT guidance.

BACKGROUND: Osteoid osteoma is a benign bone lesion characterized by nocturnal pain mostly, which may be relieved by non-steroidal prostaglandin inhibitors. Treatment by complete resection of the nidus immediately relieves the pain. Intraoperative location of the nidus may be difficult, and extensive bone resection may be necessary to ensure complete excision. Few studies have described resection of osteoid osteoma under CT guidance, and little attention has been given to lesions near the neurovascular bundle. OBJECTIVE: To report our results of osteoid osteoma resection under CT guidance, with specific attention to lesions lying near the neural structure. METHODS: Nine patients with suspected osteoid osteoma underwent resection with a 6.8 mm core drill under CT guidance. RESULTS: Histologic confirmation was obtained in seven patients, while in two there was no evidence of the nidus in the excised bone material. All nine reported complete pain relief immediately after the surgery. Postoperative CT scan showed complete removal of the osteoid osteoma. CONCLUSIONS: Removal of osteoid osteoma under CT guidance is simple, safe and allows complete removal of the nidus with low morbidity.

Adolescent↗
PubMed1999

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.

Animals↗
PubMed1999

Involvement of the foot and ankle in patients with Gaucher disease.

Of 48 children with type I Gaucher disease treated at our hospital, 11 had involvement of the foot and ankle that first appeared in adolescence. Follow-up ranged from 3 to 27 years (average, 10 years). We reviewed their clinical and radiographic histories. Patients presented with four types of pain: six (7 events of pain) complained of dull pain defined as nonspecific; seven (11 events) had severe pain caused by bone crisis; two (2 events) had moderate progressive pain caused by pathological fractures; and one had painful swollen ankles caused by degenerative arthritis. Greater awareness of these complications in patients with Gaucher disease will prevent misdiagnosis and lead to early treatment.

Adolescent↗
PubMed1998

Bone age in adolescents with schizophrenia and obsessive-compulsive disorder.

The bone age (BA), height and weight of 20 adolescents with schizophrenia and 21 matched adolescents with obsessive-compulsive disorder (COD) were measured. The BA of the schizophrenic patients was significantly higher than their chronological age (CA)(p < 0.05), while the OCD subjects' BA was non-significantly lower than their CA. In addition, the difference between CA and BA (delta ages) in the schizophrenic adolescents was significantly different from the delta ages of the OCD adolescents (p , 0.05). Gender did not significantly affect BA or delta ages. A positive correlation (r = 0.5, p < 0.01) was obtained between CA and delta ages in the schizophrenic patients but not in the OCD patients. Both groups were within the normal range of weight and height percentiles.

Adolescent↗
PubMed1998

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.

Adolescent↗
PubMed1998

MR findings in growth hormone deficiency: correlation with severity of hypopituitarism.

BACKGROUND AND PURPOSE: Growth hormone deficiency may present as an isolated deficit (IGHD) or in association with multiple deficiencies (MPHD). Previous studies have not compared the MR imaging findings with the severity of hypopituitarism. Our purpose was to determine whether MR imaging can distinguish between IGHD and MPHD. METHODS: Forty-four patients with growth hormone deficiency who were examined by MR imaging were included in this retrospective study. On the basis of the endocrinologic findings, 21 were determined to have IGHD and 23 to have MPHD. The presence, size, location, and morphologic characteristics of the stalk, the neurohypophysis, and the adenohypophysis were recorded in each case. Findings in the two groups were compared. Statistical significance was determined by t-test. RESULTS: The stalk was normal in one patient with IGHD and in none of those with MPHD; it was truncated or thin in 19 patients with IGHD (90%) and in only one with MPHD (4%); it was absent in 22 patients with MPHD (96%) and in only one patient with IGHD (5%). These differences between the two groups were highly significant. In 81% of the IGHD patients and in 91% of the MPHD patients the location of the neurohypophysis was ectopic. This difference between the two groups was not significant. Among IGHD patients, the adenohypophysis was of normal size in 13 patients (62%), small in six (29%), and absent in two (9%); the corresponding findings in MPHD patients were seven (30%), six (26%), and 10 (44%). CONCLUSION: The majority of IGHD patients had a truncated or thin stalk and a normal or small adenohypophysis. An absent stalk and adenohypophysis are characteristic of MPHD. MR imaging can contribute to the prediction of the pattern and severity of hypopituitarism in patients with growth hormone deficiency.

Adolescent↗
PubMed1997

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.

Acclimatization↗
PubMed1997

Optic chiasm glioma, electrolyte abnormalities, nonobstructive hydrocephalus and ascites.

A 4-year-old girl with optic chiasm glioma (OCG), nonobstructive hydrocephalus and ventriculoperitoneal shunt is described, in whom marked ascites developed. The ascitic fluid was protein-rich and its amount correlated with cerebrospinal fluid (CSF) protein. The CSF protein level and the amount of ascitic fluid were influenced by chemotherapy. Very unusual hypernatremia, up to 190 mEq/l with no associated alteration in mental status, was also found. It is suggested that altered absorption ability owing to the high protein content was the cause of both the nonobstructive hydrocephalus and the ascites. The unusual well being with very high sodium concentrations may have resulted from osmoreceptor dysfunction, presumably caused by hypothalamic involvement as well as by the high CSF protein. This combination of findings may point toward specific characteristics of OCG. In an effort to reduce the amount of the ascitic fluid, a further chemotherapeutic trial may be done, before converting the shunt to the vetriculoatrial system.

Ascites↗