Structure of the guinea-pig trachea at rest and in contraction

Summary The trachea of the guinea-pig measures about 47.5 mm in situ, and it shrinks to 38 mm when excised. It can be stretched to the in situ length with a load of 2–4 grams. The transverse area of its lumen measures about 4.5 mm² in the cervical portion, whereas in the lowermost thoracic portion it measures 2.8 mm², a difference of 37%. The lumen has an oval shape with the transverse diameter always exceeding the sagittal diameter. The separation between the ends of a cartilage in the dorsal region of the trachea is greater in the cervical than in the thoracic region. Elastic fibres are abundant in the tunica propria and run longitudinally; the collagen is in some areas arranged with a criss-cross pattern. The muscle is inserted on the concave aspect of each cartilage at some distance from the ends of the cartilage and it is therefore much longer than the gap between cartilage ends. Upon contraction in vitro (induced by carbachol) the muscle shortens by about 50%; there is a marked decrease of the transverse diameter of the trachea, and a certain decrease also of the sagittal diameter due to a straightening of the muscle and a change in shape and a movement of the mucosa. The cartilage ends are brought together and in the thoracic region they are bent and overlap extensively. The lumen of the trachea becomes circular and its area is reduced to 2.2 mm² in the cervical portion and 1.7 mm² in the thoracic portion.     

Bullet injury to the pituitary gland: a rare cause of panhypopituitarism

An unusual case of head injury with a direct bullet injury to the pituitary gland is described. The hormonal profile one month after the injury showed severe panhypopituitatism which did not improve one month after surgical removal of the intrasellar bullet fragment.     

Different effects of GABAergic receptors located in the ventral tegmental area on the expression of morphine-induced conditioned place preference in rat

In the present study, an unbiased conditioned place preference paradigm was used to study the effects of intra-ventral tegmental area injections of Gama-amino-butyric acid (GABA)-A and B (GABA(A) and GABA(B)) receptor agonists and antagonists on the expression of morphine-induced conditioned place preference (CPP) in rats. Subcutaneous (s.c.) injections of morphine sulfate (5 mg/kg) induced CPP. Intra-ventral tegmental area administration of the GABA(A) receptor agonist, muscimol (6 microg/rat) reduced the expression of morphine-induced CPP. Muscimol (25 microg/rat) increased the expression of CPP induced by morphine. A reduction of the expression of morphine-induced CPP was observed on intra-ventral tegmental area injection of GABA(A) receptor antagonist bicuculline (25 microg/rat). Bicuculline (10 microg/rat) increased the expression of CPP induced by morphine. Baclofen (12 microg/rat) increased where as (19 and 25 microg/rat) reduced the expression of morphine-induced CPP. Injection of CGP38345 (10, 19, 25 and 50 microg/rat) into the ventral tegmental area significantly reduced the expression of CPP induced by morphine. It is concluded that GABA(A) and GABA(B) receptor subtypes within the ventral tegmental area may have different effects on the expression of morphine-induced CPP.     

On the role of astrocytes in epilepsy: a functional modeling approach

In the present research, we extend a biologically plausible cortical neural population model (CPM), which was developed previously in the literature, by integrating the functional role of astrocytes in the synaptic transmission in the model. In other words, the original CPM is modified to consider neuron-astrocyte interaction. Then, two modified CPMs (MCPMs) are coupled via excitatory synapses; the astrocytes are also coupled through gap junctions. Using the coupled MCPMs (CMCPMs), it is demonstrated that the healthy astrocytes provide appropriate feedback control in regulating neural activity. As a result, the astrocytes compensate the coupling variations between CPMs in order to maintain the normal level of synchronized behavior. Next, malfunction of astrocytes in the regulatory feedback loop as one of the plausible causes of seizures is investigated. In this way, dysfunctional astrocytes are not any more able to regulate the excessive increase of the inter-population coupling strength. Consequently, disruption of the homeostatic function of astrocytes may initiate the hypersynchronous firing of neurons. This suggests that the neuron-astrocyte interaction may represent a novel target to develop effective therapeutic strategies for epilepsy.     

Effects of ghrelin on some plasma hormonal changes in juvenile Persian sturgeon (Acipenser persicus)

The functions of ghrelin, a novel weight-regulatory peptide, have not been intensively investigated in primitive fish. This experiment was conducted to determine whether ghrelin has a specific effect on growth hormone (GH), prolactin and cortisol levels in Persian sturgeon (Acipenser persicus). Juvenile Persian sturgeons with a mean body weight of 320?±?30?g were given a single injection of ghrelin at three doses of 0.1, 1 and 10?ng/g body weight. Control animals were injected with vehicle (sterile saline) only. Blood samples were collected at 0, 2, 4, 8, 24, 48 and 72?h after injection. The level of plasma hormones were determined by ELISA kit. As expected, ghrelin injection significantly elevated plasma GH (P?<?0.05), whereas prolactin levels did not significantly change after injection (P?>?0.05). Plasma cortisol levels decreased in fish injected with high doses of ghrelin (P?<?0.05). Ghrelin at 10?ng/g body weight had the most influence on GH release, and 1?ng/g ghrelin injection caused the lowest level of cortisol. These results show for the first time that ghrelin induces some plasma hormonal changes in sturgeon fish, as lower vertebrates, but more investigations are needed in this area.     

Erratum to: Upper extremity surgery in younger children under ultrasound-guided supraclavicular brachial plexus block: a case series

[This corrects the article DOI: 10.1007/s11832-010-0303-5.].     

T2* magnetic resonance imaging of the liver in thalassemic patients in Iran

AIM: To investigate the accuracy of T2*-weighted magnetic resonance imaging (MRI T2*) in the evaluation of iron overload in beta-thalassemia major patients. METHODS: In this cross-sectional study, 210 patients with beta-thalassemia major having regular blood transfusions were consecutively enrolled. Serum ferritin levels were measured, and all patients underwent MRI T2* of the liver. Liver biopsy was performed in 53 patients at an interval of no longer than 3 mo after the MRIT2* in each patient. The amount ...     

Iniencephaly: clinical, radiological and surgical findings

The authors report a case of iniencephaly in a 6-year-old boy with a huge occipital bone defect and encephalocele, extensive spina bifida of the cervical vertebrae and fixed retroflexion of the head due to Sprengel's deformity. He presented with some cerebellar and cranial nerve symptoms and new episodes of neck pain and drop attacks. Brain imaging confirmed progressive deformity of the brain stem, cerebellar herniation into the encephalocele sac and ventriculomegaly. Surgical repair of the encephalocele was performed with preservation of all herniated cerebellar tissue and the release of thick arachnoid adhesions to make more space to return the herniated neural tissue from the sac to the cranium. The patient was found to have progressive facial palsy and intracranial hypertension 3 days after surgery, which improved with ventriculoperitoneal shunting. Iniencephaly is generally a fatal anomaly, and only 7 such patients have been reported to have survived. Because of the fatality of this anomaly, prenatal diagnosis of iniencephly and pregnancy termination are important. The patient presented herein is only the second patient with iniencephaly and encephalocele to be operated on. The severity of associated systemic and cranial abnormalities is fundamental with regard to survival. Essential points for surgery are preparing enough space to save herniated functional neural tissues, management of associated hydrocephalus and brain stem rotation/compression due to decreased postoperative space. In the surviving child, early correction of Sprengel's deformity would provide a better aesthetic position of the neck with preservation of brachial plexus integrity.     

Cigarette smoke stimulates the production of chemokines in mast cells

Chronic obstructive pulmonary disease is a major health problem and will become the third largest cause of death in the world by 2020. It is currently believed that an exaggerated inflammatory response to inhaled irritants, in particular, cigarette smoke (CS), causes the progressive airflow limitation, in which macrophages and neutrophils are attracted by chemokines, leading to oxidative stress, emphysema, small airways fibrosis, and mucus hypersecretion. Smoking is also associated with an increase in mast cell numbers in bronchial mucosa. This study was conducted to determine the direct effects of CS on mast cell function, using murine bone marrow-derived mast cells (BMMC) as an in vitro model. BMMC were cultured from BALB/cBy mice for 3 weeks. Cells were treated with CS medium (CSM) for 30 min or 16 h. The effects of CSM on mast cell degranulation and chemokine production were measured. Moreover, we investigated the effect of CSM on IkappaB-alpha degradation and p38, Erk1/2, p65, and CREB expression by Western blotting. We found that CSM stimulated the release of chemokines in a noncytotoxic manner but did not induce mast cell degranulation. CSM induced phosphorylation of Erk1/2, p38, and CREB and increased translocation of p65 without degradation of IkappaB-alpha NF-kappaB in mast cells. The induction of chemokine production by CSM in mast cells could promote and prolong the inflammatory process. Our observations suggest that mast cells may contribute to the pathogenesis of emphysema through a direct effect of CS on the production of proinflammatory chemokines.