Running and cocaine both upregulate dynorphin mRNA in medial caudate putamen

Physical activities such as long-distance running can be habit forming and associated with a sense of well-being to a degree that justifies comparison with drug-induced addictive behaviours. To understand molecular similarities and dissimilarities controlling these behaviours in humans we compared the effects of running in running wheels to the effects of chronic cocaine or morphine administration on mRNA levels in brain reward pathways in the inbred Fischer and Lewis rat strains. These strains are both inbred from the Sprague-Dawley strain; Lewis rats display a higher preference towards addictive drugs and running than do Fischer rats. After chronic cocaine or running a similar increase of dynorphin mRNA in medial caudate putamen was found in the Lewis rat, suggesting common neuronal adaptations in this brain region to both cocaine and running. Fischer and Lewis rats both responded to cocaine with increased dynorphin mRNA levels in medial caudate putamen. However, only Lewis rats increased dynorphin mRNA after running, possibly reflecting the much higher degree of running by the Lewis strain as compared to the Fischer strain. Moreover, the running-induced upregulation of dynorphin mRNA was blocked by the opioid receptor antagonist naloxone. We suggest that running increases dynorphin mRNA by a mechanism that involves endogenous opioids. The voluntary wheel-running model in rats might be used to study natural reward and compulsive behaviours and possibly also to screen candidate drugs for treatment of compulsive disorders.     

O2-sensing after carotid chemodenervation: hypoxic ventilatory responsiveness and upregulation of tyrosine hydroxylase mRNA in brainstem catecholaminergic cells

Ventilatory responses to acute and long-term hypoxia are classically triggered by carotid chemoreceptors. The chemosensory inputs are carried within the carotid sinus nerve to the nucleus tractus solitarius and the brainstem respiratory centres. To investigate whether hypoxia acts directly on brainstem neurons or secondarily via carotid body inputs, we tested the ventilatory responses to acute and long-term hypoxia in rats with bilaterally transected carotid sinus nerves and in sham-operated rats. Because brainstem catecholaminergic neurons are part of the chemoreflex pathway, the ventilatory response to hypoxia was studied in association with the expression of tyrosine hydroxylase (TH). TH mRNA levels were assessed in the brainstem by in situ hybridization and hypoxic ventilatory responses were measured in vivo by plethysmography. After long-term hypoxia, TH mRNA levels in the nucleus tractus solitarius and ventrolateral medulla increased similarly in chemodenervated and sham-operated rats. Ventilatory acclimatization to hypoxia developed in chemodenervated rats, but to a lesser extent than in sham-operated rats. Ventilatory response to acute hypoxia, which was initially low in chemodenervated rats, was fully restored within 21 days in long-term hypoxic rats, as well as in normoxic animals which do not overexpress TH. Therefore, activation of brainstem catecholaminergic neurons and ventilatory adjustments to hypoxia occurred independently of carotid chemosensory inputs. O2-sensing mechanisms unmasked by carotid chemodenervation triggered two ventilatory adjustments: (i) a partial acclimatization to long-term hypoxia associated with TH upregulation; (ii) a complete restoration of acute hypoxic responsivity independent of TH upregulation.     

MRI study of transient cerebral ischemia in the gerbil: interest of T2 mapping

RATIONALE AND OBJECTIVES: The aim of this study was to evaluate the diagnostic use of MRI and, more precisely, the use of quantitative T2 imaging at 7 T for the early detection of neuronal cerebral alterations after transient ischemia in the gerbil. METHODS: One hundred forty-seven Mongolian gerbils were separated into four groups for which a bicarotid artery occlusion lasted for 4, 6, 8, or 10 minutes, respectively. The animals were scanned before carotid artery occlusion and at 3, 6, 10, 24, and 48 hours and 5 days after the ischemic incident. MR images were acquired on a Bruker Avance DRX300 mini-imaging system. RESULTS: Our results show that T2 mapping is able to localize brain damage induced by transient ischemia and to detect early perturbations in water content (as early as 6 hours after ischemia). CONCLUSIONS: T2 measurements in the striata are correlated with the severity of the ischemic incident, since the changes observed on the T2 images are directly proportional to the duration of occlusion.     

Intraosseous neurilemmoma of the radius: a case report

Neurilemmomas are benign tumors that arise from Schwann cells. They are rarely found on bone. We describe a neurilemmoma in a 45-year-old patient that affected the distal metaphysis of the radius. Only 1 previous case has been described in the literature. We discuss the clinical presentation, the radiographic aspect, particularly the magnetic resonance imaging characteristics, and the microscopic findings.     

Diaphragm rupture caused by closed trauma. A more and more frequent condition

The Authors report a case of rupture of the diaphragm in blunt trauma of the abdomen, to examine the more significant features of this condition whose incidence proves to be increasing, after a review of the literature data, parallel to the increase of accidents on the road and at work. They examine the most important pathogenic problems and these related to the mechanism leading to diaphragmatic lesion and they highlight the deeper pathophysiological changes suffered from the patient with such a condition. They draw attention to what they consider to be the most important aspect, and therefore the diagnosis. In fact, in accordance with the various series of cases reported in the literature, it is crucial in the diagnostic problem is when the possible cause of the rupture is suspected and necessary diagnostic cascade (Rx, echotomography, TC) is activated so to highlight the lesion. Therefore a quick diagnostic fitting is necessary for the survival of the acute patient with hernia of the thorax cavity, as well as quick surgical correction of the lesion that, as in the case described, serves to achieve the best possible anatomic-functional results.     

Rupture of the ulnar collateral ligament of the metacarpophalangeal joint of the index finger

We report a case of chronic instability due to rupture of the ulnar collateral ligament of the metacarpophalangeal joint of the index finger of the left hand. Because of persistent instability after the initial conservative treatment, surgical treatment was required.     

Clinical experience with functional electrical stimulation-assisted gait with Parastep in spinal cord-injured patients

STUDY DESIGN: Clinical evaluation of the Parastep method, a six-channel transcutaneous functional electrical stimulation device, in spinal cord-injured patients. OBJECTIVES: To investigate the motor performances of this new technique regarding energy expenditure and to evaluate its advantages and limitations, especially in social activities involving ambulation. METHODS: This study was conducted in 15 thoracic spine-injured patients. The lesion was complete except in two patients. The gait ability and the functional use were judged clinically. Energy cost was evaluated from heart rate, peak oxygen uptake, and lactatemia. RESULTS: Thirteen patients completed the training (mean: 20 sessions) and achieved independent ambulation with a walker. The mean walking distance, without rest, was 52.8 +/- 69 m, and the mean speed was 0.15 +/- 0.14 m/sec. One patient with incomplete lesion, who had been nonambulatory for 8 months after the injury, became able to walk without functional electrical stimulation after five sessions. The follow-up was 40 +/- 11 months. Five patients pursued using functional electrical stimulation-assisted gait as a means of physical exercise but not for ambulation in social activities. The patients experienced marked psychological benefits, with positive changes in their way of life. In three subjects, a comparison of physiologic responses to exercise between a progressive arm ergometer test and a walking test with the Parastep (Sigmedics, Inc., Northfield, IL) at a speed of 0.1 m/sec was performed, showing that the heart rate, the peak oxygen uptake, and lactatemia during gait were close to those obtained at the end of the maximal test on the ergometer. CONCLUSIONS: In spite of its ease of operation and good cosmetic acceptance, the Parastep approach has very limited applications for mobility in daily life, because of its modest performance associated with high metabolic cost and cardiovascular strain. However, it can be proposed as a resource to keep physical and psychological fitness in patients with spinal cord injury.     

Osteoid osteoma of the spine treated with percutaneous computed tomography-guided thermocoagulation

STUDY DESIGN: Two cases are reported in which an osteoid osteoma of the lumbar spine was treated with CT-guided thermocoagulation. OBJECTIVES: To review an alternative and minimally invasive treatment for spinal osteoid osteomas. SUMMARY OF BACKGROUND DATA: Surgical resection of a spinal osteoid osteoma can, depending on the location, be a formidable undertaking. Bone scintigraphy can be helpful in intraoperative identification. More recently, resection through a computed tomography-guided drill hole was found to minimize exposure. Using a thermocoagulation probe, as has been used in osteoid osteoma of the extremities, may be technically easier and cause less morbidity. METHOD: With the patient under general anesthesia, a bone biopsy cannula was introduced into the center of the osteoid osteoma. Material was subjected to histologic examination. A thermocoagulation probe was then inserted and heated to 90 C for 4 minutes. The two patients were kept overnight for observation. RESULTS: Both patients had complete pain relief and no evidence of recurrence after 2 years' follow-up. There were no complications. Scoliosis resolved in one patient and persisted in the other. CONCLUSION: Percutaneous computed tomography-guided thermocoagulation is a minimally invasive and technically straightforward method to achieve ablation of a spinal osteoid osteoma. No complications were encountered in these two patients. Future research should focus on the safety of thermocoagulation, especially cephalad to the level of the conus medullaris.     

Neurodevelopmental disorders in males related to the gene causing Rett syndrome in females (MECP2).

Mutations in the MECP2 (methyl-CpG-binding protein 2) gene are known to cause Rett syndrome, a well-known and clinically defined neurodevelopmental disorder. Rett syndrome occurs almost exclusively in females and for a long time was thought to be an X-linked dominant condition lethal in hemizygous males. Since the discovery of the MECP2 gene as the cause of Rett syndrome in 1999, MECP2 mutations have, however, also been reported in males. These males phenotypically have classical Rett syndrome when the mutation arises as somatic mosaicism or when they have an extra X chromosome. In all other cases, males with MECP2 mutations show diverse phenotypes different from classical Rett syndrome. The spectrum ranges from severe congenital encephalopathy, mental retardation with various neurological symptoms, occasionally in association with psychiatric illness, to mild mental retardation only. We present a 21-year-old male with severe mental retardation, spastic tetraplegia, dystonia, apraxia and neurogenic scoliosis. A history of early hypotonia evolving into severe spasticity, slowing of head growth, breathing irregularities and good visual interactive behaviour were highly suggestive of Rett syndrome. He has a de novo missense mutation in exon 3 of the MECP2 gene (P225L). The clinical spectrum and molecular findings in males with MECP2 mutations are reviewed.