Postnatal development of calretinin- and parvalbumin-positive interneurons in the rat neostriatum: an immunohistochemical study.

On the basis of cytochemical and morphologic differences, two classes of gamma-aminobutyric acidergic (GABAergic) interneurons expressing calcium-binding proteins have been identified in the striatum of adult animals: neurons expressing either parvalbumin (PV) or calretinin (CR). The function of these calcium-binding proteins is not clear, however, they are associated with distinct classes of inhibitory interneurons within the adult neostriatum. By using immunocytochemical techniques, we analyzed the postnatal maturation and the spatiotemporal distribution of PV- and CR-positive neurons in the rat neostriatum compared with a third class of interneurons characterized by the expression of the acetylcholine-synthesizing enzyme, choline acetyltransferase (ChAT). PV-positive cells appeared initially on postnatal day 9 in the lateral region of the striatum. During postnatal weeks 2 and 3, the numbers of PV-positive neurons increased, and this cell population spread progressively in a lateromedial direction. In contrast, CR-expressing neurons were present at birth. During the first few days after birth, the number of CR-immunoreactive cells increased, reaching a peak on postnatal day 5 before declining during the following 2 weeks. A mediolateral gradient was evident temporarily. ChAT-containing neurons were detectable at birth in the lateral striatum. During postnatal weeks 1 and 2, the neurons matured along a lateral-to-medial gradient. The results indicate that the maturation of striatal interneurons is regulated differentially during postnatal development, resulting in a distinct spatiotemporal genesis of phenotypes. The sequential expression of CR and PV suggests a stage-dependent development of subsets of inhibitory interneurons and, hence, the stage-dependent maturation of functionally distinct inhibitory circuits within the neostriatum.

Reverse transcriptase-polymerase chain reaction study of anion exchanger-2 in canine tissues and different Madin-Darby canine kidney cell types.

Reverse transcriptase-polymerase chain reaction (RT-PCR) of mRNA from canine large intestine, skeletal muscle, pancreas, kidney, and spleen and from cultured wild-type and C7 and C11 Madin-Darby canine kidney (MDCK) cells revealed considerable variation in anion exchanger (AE)1 and AE2 mRNA levels between the tissues. Similar high levels of AE2 mRNA were detected in all the MDCK cell populations. AE2 in MDCK cells is probably the basolateral Cl-/HCO3- exchanger common to the principal and beta-intercalated cells.

Time-related changes in connexin mRNA abundance in the rat neocortex during postnatal development.

Gap junction coupling between neurons is important for the temporal and spatial co-ordination of neocortical development and can be visualised by dye-coupling. Neuronal dye-coupling in the rat neocortex is extensive during the first 2 postnatal weeks and diminishes rapidly thereafter. We used RT (reverse transcriptase)-PCR to investigate the time-related changes in mRNA expression for the connexins (Cx) Cx 26, Cx 30, Cx 32, Cx 36, Cx 37, Cx 40, Cx 43, Cx 45 and Cx 46 as well as for beta-actin and GAPDH in rat neocortex during the first 6 postnatal weeks. The time courses for mRNA expression for GAPDH, Cx 30, Cx 36 and Cx 43 were also investigated by northern blotting. Cx 30 and Cx 45 mRNA abundance showed no time-dependent changes during the early postnatal period. The relative abundance of Cx 32, Cx 43 and Cx 46 mRNA increased significantly during the first 2-3 weeks and then remained relatively constant during weeks 3-6. The relative abundance of Cx 26, Cx 36, Cx 37 and Cx 40 mRNA also increased significantly during the first 10-15 postnatal days but then declined significantly from their peak values during weeks 3-6. beta-actin mRNA expression showed no time-related changes but GAPDH mRNA expression increased significantly during the first postnatal week, then remained constant. The time-dependent changes in mRNA relative abundance for GAPDH, Cx 36 and Cx 43 determined by northern blotting corroborate the results from the RT-PCR study. None of the Cx exhibited time-dependent changes in mRNA expression in homogenates of rat neocortex which parallel the changes in neuronal dye-coupling during postnatal development.

Diagnostic value of chest radiography, computed tomography and tumour markers in the differentiation of malignant from benign solitary pulmonary lesions.

BACKGROUND: The aim of this prospective study was to assess the diagnostic value of the imaging modalities (chest radiography, spiral computed tomography (SCT) and high-resolution computed tomography (HRCT)) and the tumour markers (carcinoembryonic antigen (CEA), cytokeratin marker (CYFRA 21-1) and neuron-specific enolase (NSE)) in the differentiation of malignant (MSPLs) from benign solitary pulmonary lesions (BSPLs). PATIENTS AND METHODS: Solitary pulmonary lesions (SPLs) were examined, evaluated and then completely removed by surgery in 104 consecutive patients (MSPLs n = 81, BSPLs n = 23). Chest radiography was performed with frontal and lateral views, SCT was carried out with a slice thickness of 8 mm and HRCT with a slice thickness of 1 mm and a 12-cm field of view. For the tumour marker analysis, serum concentrations were determined 1-3 days prior to surgery by ELISA for CEA and CYFRA 21-1 and by IRMA for NSE using commercially available assay kits. The cut-off values were set at 3 ng/ml (for non-smokers) and 5 ng/ml (for smokers) for CEA, at 3.3 ng/ml for CYFRA 21-1 and at 12.5 ng/ml for NSE. RESULTS: Using any one of the characteristics with a significance level of P <0.01, the identification of MSPLs using chest radiography showed a sensitivity of 64.2% and a specificity of 82.6%, using SCT a sensitivity of 88.9% and a specificity of 60.9% and using HRCT a sensitivity of 91.4% and a specificity of 56.5%. For the identification of MSPLs using CEA a sensitivity of 27.2% and a specificity of 87.0% (accuracy of 40.4%) was observed. Using CYFRA 21-1 a sensitivity of 19.8% and a specificity of 100.0% (accuracy of 37.5%) and using NSE a sensitivity of 13.6% and a specificity of 100. 0% (accuracy of 32.7%) was found. CONCLUSIONS: Using chest radiography, SCT and HRCT, a precise morphological assessment of the periphery of the pulmonary lesion and the adjacent visceral pleura is necessary to distinguish MSPLs from BSPLs. Tumour markers used alone or in combination with the imaging methods brought no additional benefits, in terms of sensitivity and accuracy, over the diagnostic imaging methods alone. However, the tumour markers exhibited a far superior specificity (100% for CYFRA 21-1 and NSE) compared with the imaging methods.

Hybrid rendering of the chest and virtual bronchoscopy [corrected].

Thin-section spiral computed tomography was used to acquire the volume data sets of the thorax. The tracheobronchial system and pathological changes of the chest were visualized using a color-coded surface rendering method. The structures of interest were then superimposed on a volume rendering of the other thoracic structures, thus producing a hybrid rendering. The hybrid rendering technique exploit the advantages of both rendering methods and enable virtual bronchoscopic examinations using different representation models. Virtual bronchoscopic examinations with a transparent color-coded shaded-surface model enables the simultaneous visualization of both the airways and the adjacent structures behind of the tracheobronchial wall and therefore, offers a practical alternative to fiberoptic bronchoscopy. Hybrid rendering and virtual endoscopy obviate the need for time consuming detailed analysis and presentation of axial source images.

Preliminary evidence for the enterohepatic circulation of progesterone in the pig.

In two gilts, following doses of either 47.7 or 64.6 mumol progesterone, a secondary increase in steroid concentration in portal and mesenteric blood plasma occurred 35-40 min after dosing or 10-15 min after an intravenous (i.v.) dose of cholecystokinin. It is suggested that this increase is splanchnic blood progesterone concentration indicates that the steroid undergoes enterohepatic circulation. In five ovariectomized gilts given single i.v. doses of 47.7 mumol progesterone, the steroid was cleared from the circulating plasma bi-exponentially; the mean half-lives (t 1/2) of the two components were 2.47 (+/- 0.36) and 33.5 (+/- 6.63) min. The t 1/2 of the first component was compatible with the liver being a principal organ of clearance.