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PubMed2003

Virological control of groundwater quality using biomolecular tests.

Deep groundwater, even if generally protected, could be contaminated by surface or rain water infiltration through soil fractures, septic tanks, cesspits, land irrigation, disposal of wastewater and disposal of muds from depuration systems. The sanitary importance of such possible contamination is related to the different uses of the water and it is at the maximum level when it is intended for human use. Routine microbiological analyses do not consider viruses, only bacterial parameters, as contamination indicators. However, it is known that enteric viruses can survive a long time in deep aquifers and that they may not always be associated with bacterial indicators. The virological analysis of waters intended for drinking use is provided only as an occasional control exercised at the discretion of the sanitary authority. Technological difficulties with obtaining data about groundwater viral contamination led to a study to devise rapid and efficient methods for their detection and the application of these methods to samples from different sources. Four acid nucleic extraction techniques have been tested (classic proteinase K- phenol/chloroform, QIAamp Viral RNA Kit (Qiagen), SV Total RNA Isolation System (Promega) and NucleoSpin Virus L (Macherey-Nagel). Sensitivity and specificity of RT-PCR protocols for entero- (EV), hepatitis A (HAV) and small round structured (SRSV) viruses have been verified. Deep groundwater samples (100 L) were concentrated (2-step tangential flow ultrafiltration) and the concentrate contaminated with serial 10-fold dilutions of a known titre of poliovirus type 3. Extracted RNA was concentrated (microcon-100) and analysed by RT-PCR using specific EV primers and visualising amplification products by agarose gel electrophoresis. In addition, two different methods of RT-PCR for non-cultivable viruses have been tested: (a) RT-PCR and nested RT-PCR for HAV and (b) RT-PCR with generic primers and RT-PCR with specific primers for SRSV. Different specificity tests have been carried out in the presence of some of the commoner microorganisms. The most efficient, sensitive and specific protocols were used to test 35 x 100L deep groundwater samples. Sample concentrates were split with one part treated with chloroform and analysed by cell culture (BGM and Frp/3, derived from FrHK/4, cells) and the other tested by RT-PCR for HAV, EV and SRSV. Results demonstrated the high efficiency of the classic and QIAamp methods. Microcon-100 did not increase the sensitivity of the technique used. The highest sensitivity was observed for RT-PCR with specific primers for SRSV and for nested RT-PCR for HAV. One sample showed a cytopathic effect, not confirmed at the third subculture, while the RT-PCR allowed the detection of echovirus 7. Cell culture did not allow detection of the majority of the enteric viruses while PCR gave sensitive, specific and rapid detection of a range of agents in the same samples. Even if it was impossible to fix a virological quality standard, it would be necessary to find a viral indicator in order to achieve a complete preventive check which would be particularly useful in some cases (e.g. water never used before, after pollution accidents, for seasonal checking).

DNA, Viral↗
PubMed2006

Early experiences with diffusion tensor imaging and magnetic resonance tractography in stroke patients.

INTRODUCTION: Recent advances in magnetic resonance (MR) diffusion tensor imaging technique enable evaluation of the anisotropy of white matter tracts in-vivo, as well as the integrity of fibre tracts and their orientation. We describe our initial experiences with diffusion tensor imaging and MR tractography techniques to evaluate the structural degeneration of white matter tracts following stroke. METHODS: Diffusion tensor imaging data were acquired in 11 cases with stroke on a 3T MR imaging scanner, with three-dimensional diffusion tensor imaging-based colour maps and MR tractography performed offline. We evaluated the spatial relationships of the eloquent white matter tracts to the infarcts and areas of haemorrhage, and classified therewith the tracts as either disrupted or displaced. We compared these with the clinical severity of the neurological deficits and prognosis. RESULTS: A good correlation was found between tractography findings and patient's clinical recovery. All the patients with disruption of white matter tracts had residual deficits on clinical follow-up, whereas the patients with displaced tracts had near complete neurological recovery. CONCLUSION: Diffusion tensor imaging and MR tractography provide a novel and useful method to directly visualise changes in the white matter tracts in stroke. This can potentially allow clinical-imaging correlation with prognostic potential.

Aged↗
PubMed1997

Development of phrenic motoneuron morphology in the fetal rat.

This study examined the morphological changes that a homogeneous mammalian spinal motoneuron population undergoes during foetal development. Retrograde labelling of the phrenic nerve with the carbocyanine dye, DiI, was used to visualise developmental changes in phrenic motoneuron morphology within the cervical spinal cord of perinatal rats from embryonic day (E) 13.5 to birth (ca. E21). Groups of intimately associated phrenic somata had migrated into the ventromedial region of cervical segments C3-C6 by E14. This migration was followed by their progressive compaction into a tightly aligned column by E18. During this period, close contact was maintained between phrenic somata throughout the motor pool, suggestive of the presence of gap junctions. From E15 to E18, extensive dendritic arborisations fanned out dorsolaterally and ventromedially into the white matter and the floor plate. By E19, however, dendritic fasciculation and retraction and the extension of newly formed rostrocaudally projecting dendrites had resulted in the approximation of the dendritic morphology observed at birth. These data demonstrate that morphological maturation of phrenic motoneurons occurs subsequently to the onset of functional recruitment and the arrival of central processes of dorsal root ganglion neurons within the ventral horn (ca. E17). By birth, a number of immature features remain, including a larger proportion of neurites that project into the white matter and into the floor plate, the presence of growth cones on a number of dendrites, and close contact between populations of contralaterally derived dendrites.

Animals↗
PubMed2004

Managing patient dose in digital radiology. A report of the International Commission on Radiological Protection.

Digital techniques have the potential to improve the practice of radiology but they also risk the overuse of radiation. The main advantages of digital imaging, i.e. wide dynamic range, post processing, multiple viewing options, and electronic transfer and archiving possibilities, are clear but overexposures can occur without an adverse impact on image quality. In conventional radiography, excessive exposure produces a 'black' film. In digital systems, good images are obtained for a large range of doses. It is very easy to obtain (and delete) images with digital fluoroscopy systems, and there may be a tendency to obtain more images than necessary. In digital radiology, higher patient dose usually means improved image quality, so a tendency to use higher patient doses than necessary could occur. Different medical imaging tasks require different levels of image quality, and doses that have no additional benefit for the clinical purpose should be avoided. Image quality can be compromised by inappropriate levels of data compression and/or postprocessing techniques. All these new challenges should be part of the optimisation process and should be included in clinical and technical protocols. Local diagnostic reference levels should be re-evaluated for digital imaging, and patient dose parameters should be displayed at the operator console. Frequent patient dose audits should occur when digital techniques are introduced. Training in the management of image quality and patient dose in digital radiology is necessary. Digital radiology will involve new regulations and invoke new challenges for practitioners. As digital images are easier to obtain and transmit, the justification criteria should be reinforced. Commissioning of digital systems should involve clinical specialists, medical physicists, and radiographers to ensure that imaging capability and radiation dose management are integrated. Quality control requires new procedures and protocols (visualisation, transmission, and archiving of the images).

Body Burden↗
PubMed2003

Indium-111-labelled octreotide scintigraphy in the diagnosis and management of non-iodine avid metastatic carcinoma of the thyroid.

Treatment of differentiated thyroid cancer is a success of modern medicine with the use of radioiodine ((131)I). However, a significant proportion of thyroid cancers may be non-iodine avid. Thyroid tumours are known to express somatostatin receptors. Octreotide, an analogue of somatostatin, can be combined with a radioactive isotope, such as (111)In-DTPA(0) to visualise tumours with high concentrations of somatostatin receptors. We assessed 18 patients with histologically proven metastatic or locally recurrent non-iodine avid thyroid carcinoma to determine the usefulness of (111)In-DTPA(0) octreotide scintigraphy compared to conventional radiology in diagnosing sites of metastasis. The diagnosis of metastatic disease was made using conventional radiology and all had prospective scintigraphy using (111)In-DTPA(0)octreotide. Of the 18 patients, 14 had octreotide-positive scans. In eight, the octreotide scans identified the same sites of metastases as conventional radiology, that is, were concordant. In nine patients, conventional radiology showed more extensive disease than revealed on the octreotide scans. In one patient with widespread bone metastases, octreotide gave a more detailed assessment of metastatic disease than conventional radiology. These data indicate that (111)In-DTPA(0)octreotide imaging for patients with non-iodine avid carcinoma of the thyroid may be a useful diagnostic and staging tool. One patient with Hurthle cell carcinoma metastatic to bone and a positive octreotide scan has been treated with (90)yttrium-labelled octreotide.

Antineoplastic Agents, Hormonal↗
PubMed1992

3-Oxoacyl-[ACP] reductase from oilseed rape (Brassica napus).

3-Oxoacyl-[ACP] reductase (E.C. 1.1.1.100, alternatively known as beta-ketoacyl-[ACP] reductase), a component of fatty acid synthetase has been purified from seeds of rape by ammonium sulphate fractionation, Procion Red H-E3B chromatography, FPLC gel filtration and high performance hydroxyapatite chromatography. The purified enzyme appears on SDS-PAGE as a number of 20-30 kDa components and has a strong tendency to exist in a dimeric form, particularly when dithiothreitol is not present to reduce disulphide bonds. Cleveland mapping and cross-reactivity with antiserum raised against avocado 3-oxoacyl-[ACP] reductase both indicate that the multiple components have similar primary structures. On gel filtration the enzyme appears to have a molecular mass of 120 kDa suggesting that the native structure is tetrameric. The enzyme has a strong preference for the acetoacetyl ester of acyl carrier protein (Km = 3 microM) over the corresponding esters of the model substrates N-acetyl cysteamine (Km = 35 mM) and CoA (Km = 261 microM). It is inactivated by dilution but this can be partly prevented by the inclusion of NADPH. Using an antiserum prepared against avocado 3-oxoacyl-[ACP] reductase, the enzyme has been visualised inside the plastids of rape embryo and leaf tissues by immunoelectron microscopy. Amino acid sequencing of two peptides prepared by digestion of the purified enzyme with trypsin showed strong similarities with 3-oxoacyl-[ACP] reductase from avocado pear and the Nod G gene product from Rhizobium meliloti.

3-Oxoacyl-(Acyl-Carrier-Protein) Reductase↗
PubMed1997

A multidimensional partition analysis of SSFP image pulse sequences.

The k-space description, of MRI pulse sequences, has been combined with a partition model in order to model the image reconstruction and the contrast behaviour found in SSFP pulse sequences. A partition represents the magnetisation created, due to excitation by a given rf pulse. In the present model, it is visualised as a set of parameters rather than a vector sum taken over a collection of spins. A multidimensional parameter space, where each dimension is associated with one of the partition parameters, is introduced in order to describe the interaction between partitions and pulse sequence events (e.g., rf pulses and gradients). The three k-space dimensions form the first three dimensions and higher orders are used to handle phase dispersions due to diffusion and main field inhomogeneities. The model makes it possible to perform fast simulation of images resulting from general SSFP pulse sequences. A computer implementation generates images (256 matrix), containing more than 10 different T1/T2 combinations, in less than 45 s on a 120 MHz Pentium computer. The contrast behaviour and signal intensities found in simulated images show excellent agreement with data generated using a clinical MRI scanner system.

Computer Simulation↗
PubMed2002

An in vitro model for detecting skin irritants: methyl green-pyronine staining of human skin explant cultures.

We evaluated the potential of human organotypic skin explant cultures (hOSECs) for screening skin irritants. Test chemicals were applied to the epidermis of the skin explants which were incubated for 4, 24 or 48 h in tissue culture medium. A decrease in epidermal RNA staining, visualised in frozen sections using a modified methyl-green pyronine (MGP) staining procedure, was used as a marker of irritancy. A decrease in epidermal RNA after a 4-, 24- or 48-h exposure to a certain concentration of a test chemical equated to a MGP score of 3, 2 or 1, respectively. The MGP score was 0 if there was no keratinocyte cytotoxicity after a 48-h exposure. A minimum of three donors were used per chemical and the average MGP score was used to classify the chemical as irritant or not. Chemicals with an average MGP score > or =1.5 were classified as irritants (R38), at that concentration. Chemicals with a MGP score <1.5 were not classified (NC), at that concentration. The results obtained using human skin in vitro were compared with published data obtained using cultured porcine skin, the cutaneous Draize test (from this point referred to as the "rabbit skin irritation test") and volunteer studies. There was an excellent correlation between the classification of a chemical, as R38 or NC, based on hOSEC and results of volunteer studies. The hOSEC model predicted perfectly the irritation hazard of the 22 chemicals for which volunteer data were available. The porcine OSEC correctly predicted the classification of 21 of 22 (95%) chemicals and the rabbit skin irritation test correctly predicted the classification of 14 of 15 chemicals (93%) for which data were available. In conclusion, MGP staining of human skin explant cultures can be used to predicted human skin irritancy in vivo. In addition, the data validate the use of porcine skin as an alternative to human skin for screening for dermal irritants in vitro.

Animal Testing Alternatives↗
PubMed2004

[Identification of Langerhans cells in dermatology].

This paper describes our own findings on the role of Langerhans' cells in dermatology and discusses literature data on their detection in seven different dermatoses. The skin is an integral part of immune system. During the past 30 years, increasing evidence has been accumulated that the skin contains cellular elements which are needed for the initiation and expression of immune response. Langerhans' cells (LCs) are dendritic cells originating in the bone marrow. They reside mainly within stratified squamous epithelia and constitute approximately 2-4% of epithelial cells. LCs are epidermal antigen presenting cells which play a crucial role in allergic contact hypersensitivity, viral diseases, graft versus host disease and elimination of neo-plastic cell clones. They express antigens conjugated with major histocompatibility complex (MHC) class II positive molecules on their surfaces for presentation to T-helper lymphocytes. LCs cannot be identified in routinely prepared histologic testing but can be visualised at the light microscope level by histochemical and immunologic techniques. Appropriate methods for the detection of Langerhans' cells in dermatology (also shown by our own experience) are histoenzymatic methods of adenosintriphosphatase (ATP-ase), acid phosphatase (AP), alpha-naphthylacetatesterase (ANAE and peroxidase-antiperoxidase immunohistochemistry method with polyclonal S-100 protein antibody (PAP). LCs are the only cells in normal skin with ATP-ase activity. Histoenzymatic methods used in patients with atopic dermatitis, vitiligo, mycosis fungoides, Behcet's disease, lichen ruber planus, psoriasis vulgaris, irritant dermatitis and allergic contact dermatitis demonstrated LSs in epidermis and dermis. ANAE and AP showed concordance and were suitable histochemical markers for LC distribution and macrophages in the dermis in mycosis fungoides, atopic dermatitis, psoriasis vulgaris, irritant chronic dermatitis and Bechet's disease. Our experience of the human skin showed a strong activity of calcium-activated adenosine triphosphatase in LCs. LCs in the guinea pig skin can be demonstrated by Mg++ and Ca++ activated adenosine triphosphatase, but a stronger activity of Ca++ activated adenosine triphosphatase in LCs after irritation. Ca++ ATP-ase as an indicator of energy-dependent pump is the reflection of intracellular calcium level, which is a significant factor for regulating the growth and metabolism of the cells. LCs are found as target cells during the efferent phase of contact allergic reaction. Immunohistochemical methods, define the role of LCs in dermatology more precisely and allow complete immunologic recognition within the epidermis.

Dermatitis, Allergic Contact↗
PubMed2005

Ventricular myocardial architecture as visualised in postmortem swine hearts using magnetic resonance diffusion tensor imaging.

OBJECTIVE: The three-dimensional arrangement of the ventricular myocardial architecture remains controversial, in part because histological assessment is difficult to achieve, while anatomic dissections are, of necessity, destructive. In this study, we describe how the use of magnetic resonance diffusion tensor imaging has permitted us to reconstruct with precision the architecture of the ventricular myocardial fibres in the post-mortem swine heart. METHODS AND RESULTS: We obtained diffusion-weighted spin-echo measurements of autopsied porcine hearts using a whole body MR system. We calculated the diffusion tensor and the corresponding eigenvectors on a voxel-by-voxel basis. This permitted us to colour code the fibres, and reconstruct them by connecting voxels in direction of the largest eigenvector. Such reconstructions show that, in the middle layer of the left ventricle, most of the fibres have a circular orientation, albeit that a far from negligible component runs in a transverse direction. With increasing distance from the epicardium, the orientation of the fibres shows a continuous change in angulation with respect to an axis normal to the epicardium. CONCLUSION: Our data presented here supports the concept that the ventricular mass is arranged as a complex three-dimensional mesh of tangential and intruding fibres. The data offers no support for the concept of a "unique myocardial band". The method has the potential to detecting deviations from this basic normal architecture, being capable of reconstructing the ventricular mass so as to assess the spatial coordinates of any single fibre strand. The technique, therefore, has major potential clinical applications in the setting of the failing or malformed heart, potentially being able to identify either systematic or regional disarray of the myocardial fibres.

Animals↗
PubMed1992

Localization and function of the D3 dopamine receptor.

A novel dopamine receptor has been recently cloned, which differs from D1 and D2 receptors by its sequence, localization, pharmacology and possibly signalling system, hence its designation as D3 receptor. The D3 receptor cDNA was obtained by a combination of screenings of DNA libraries and PCR polymerase chain reaction experiments. It encodes a protein with a predicted structure consisting in 7 transmembrane domains indicating that it belongs to the G-protein coupled receptor family. Its global homology is 52% with the D2 receptor but 78% if only transmembrane domains are considered. Two shorter transcript variants, in addition to the full-length cDNA were detected by PCR in various rat brain regions. The shorter transcripts are generated by alternative splicing and encode two putative proteins respectively interrupted after the second transmembrane domain and lacking the second extracytoplasmic loop. After transfection of this latter isoform into cultured cells, no dopaminergic activity could be detected. These shorter splice variants may regulate the number of active D3 receptors. The human D3 receptor was also cloned using similar approaches with rat D3 receptor cDNA probes and was found highly homologous to the rat receptor, except in the third intracytoplasmic loop. The human D3 receptor gene was assigned to the chromosome 3 at q13.3 band. Visualisation of D3 receptor mRNA in rat brain by in situ hybridization indicated a predominant expression of the message in the ventral striatum and other "limbic" areas. There is no overlap in the distributions of D2 and D3 receptor mRNAs in discrete structures, suggesting that the two transcripts are expressed by different cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1998

[PET in neuroendocrine tumors].

With the radionuclide tracers available today, 50-90 per cent of neuroendocrine tumours of the gastro-intestinal tract can be visualised with PET (positron-emission tomography). PET also enables the effect of tumour treatment to be monitored in terms of biochemical and functional variables, which is not possible with other radiological techniques. Owing to the very good tumour resolution possible with PET, it serves as a complement to other routine methods such as computed tomography and ultrasonography, and can be used to screen the chest and abdomen for small primary tumours that can not be detected with other methods. In several pre-operative trials PET has been shown to demonstrate more changes in the pancreas and liver than was possible with other methods. In the near future it will be possible to demonstrate the presence of and quantify growth factor receptors, hormones, enzymes, DNA synthesis, mRNA synthesis and protein synthesis. Access to these tumour biological data will be of crucial importance to the individualisation of treatment.

Forecasting↗
PubMed1984

[2-dimensional echography in the preoperative evaluation of mitral stenosis].

2D echocardiography has become one of the most important investigations in the preoperative assessment of mitral stenosis. This study was undertaken to determine the reliability of the information so obtained, by comparison with the surgical appearances. The study population consisted of 104 patients (average age 45 years, 76% women) undergoing open heart surgery for pure mitral stenosis (72%) or mixed mitral valve disease (28%) between 1980 and 1981. All underwent 2D echo using a phased array Aloka SSD 800 80 degrees sector scanner. Cardiac catheterisation was performed in 102 cases and left ventricular angiography in 89 cases. The echocardiogramme was interpreted by an observer who had no knowledge of the surgical results. The mitral surface area, the condition of the valves and subvalvular apparatus and the predictive value of the possible surgical technique were analysed. The 2D echo mitral surface area was estimated by planimetry and quantitatively by using the Gorlin formula during catheterisation and by the surgical description preoperatively. 2D echo was more sensitive than M mode in the detection of severe mitral stenosis (90% vs 73%, p less than 0,01). The 2D echo-Gorlin correlation was quite good (R = 0,70, p less than 0,01) but was worse when the valves were very thickened. When compared with the surgical observations, 87% of the 2D echo data was correct. The thickness of the valves, their amplitude, the diastolic bowing of the anterior leaflet and the presence of calcification were assessed by 2D echo. The echo-surgical results matched perfectly in 76% of cases. The usual cause of error was underestimation of the degree of valvular damage. The valvular bowing and thickness were the most useful signs. Dense, brilliant echos of valvular calcification were found in only 58% of surgically proven cases of valvular calcification, but the error was often related to fine calcification, not visible on fluoroscopy, or to its localisation on the posterior leaflet. The subvalvular apparatus was evaluated in over 93% of patients, a complete study being possible in 73% of them. The 2D echo-surgical correlations were excellent in 90% of the cases in which it had been completely visualised. The chordal thickening was correctly predicted in 79% of cases. The surgical assessment was more pessimistic in 1/3 of cases in which the chordae appeared to be of normal thickness. The length of the chordae was correctly predicted in 68% of cases. The surgical assessment was more pessimistic in 1/2 of cases in which the chordae appeared to be of normal length.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1999

Measurement of clinical attachment levels using a constant-force periodontal probe modified to detect the cemento-enamel junction.

The handpiece of a Florida sleeve probe was modified to create a flange with the capability to detect the cemento-enamel junction (CEJ). This new instrument (the Pressure-controlled, Automated, Standardised Handpiece or Florida PASHA probe) was used to determine whether (a) the CEJ could be reproducibly detected in dried, human skulls and (b) clinical attachment levels could be reliably measured in human subjects. When using the Florida PASHA probe to detect the CEJ at 157 different sites in four dried, human skulls, there were no statistically significant (p > or = 0.15) differences in mean CEJ detection measurements for any of the three participating examiners; either when the CEJ was visualised or obscured. The mean differences between first and second replicates ranged from 0.00 to 0.08 mm. Intraclass correlation coefficients (ICCs) of repeated measures in both conditions ranged from 0.70 to 0.83 for tactile CEJ detection (CEJ obscured), and from 0.95 to 0.96 for visual detection (CEJ visible). In human studies, the Florida PASHA probe was used by two examiners to determine clinical attachment levels (CAL) at 660 sites in 5 human subjects undergoing supportive periodontal therapy. Intra-examiner agreement of replicate measurements recorded by the probe, as measured by calculating ICCs, ranged from 0.79 to 0.85 for the 2 examiners, respectively. A statistically significant inter-examiner difference in mean CAL measurements when using the Florida PASHA probe was found (p<0.001). Notwithstanding this difference, inter-examiner agreement was good, with an ICC of 0.83. These data suggest that the Florida PASHA probe can reproducibly detect the CEJ and is proposed as a tool for measuring CAL in humans.

Alveolar Bone Loss↗
PubMed1997

Numerical chromosomal aberrations in Hodgkin's disease detected by in situ hybridisation on routine paraffin sections.

AIMS: To visualise directly numerical chromosomal aberrations and polyploidy in both Hodgkin and Reed Sternberg (HRS) cells and background cells from cases of Hodgkin's disease using in situ hybridisation. METHODS: Non-isotopic DNA in situ hybridisation was applied to interphase cell nuclei of Hodgkin's disease within routine paraffin embedded tissue sections. Two a satellite DNA probes, specific for chromosomes 3 and 12, were used to evaluate the feasibility of this approach. Double labelling with immunocytochemical detection of the CD30 antigen was used to identify HRS cells. Cytogenetic normal diploid and triploid placental tissue served as controls. RESULTS: The eight cases of Hodgkin's disease investigated displayed frequent polysomy, while the majority of background cells showed disomy signals. CONCLUSIONS: Numerical chromosomal aberrations were detected in HRS cells from eight cases of Hodgkin's disease by in situ hybridisation. These data show that in Hodgkin's disease HRS cells frequently display polyploidy compared with background cells and are, therefore, probably the only neoplastic component in this disease. Correlations between polysomy and tumour type or grade could not be made from these data owing to the limited number of cases examined and to problems with interpreting data from truncated nuclei.

Adolescent↗
PubMed1994

Structural determinants of substrate selection by the human insulin-receptor protein-tyrosine kinase.

Using NMR spectroscopy to visualise tyrosine phosphorylation kinetics in real time, we have investigated the sequence-dependent determinants of the selectivity of the human insulin receptor protein-tyrosine kinase for different tyrosine residues. The peptides used encompass the multiple-tyrosine-containing autophosphorylation site sequences from the insulin receptor kinase core domain (Tyr1158, Tyr1162 and Tyr1163) and from its specific C-terminal tail domain (Tyr1328 and Tyr1334). Comparison of the phosphorylation kinetics with those found for the tyrosine residues on a peptide comprising the regulatory tyrosine phosphorylation site of cdc2 points to the role of the primary sequence context of the phosphate acceptor. The particularly deleterious influence of a basic residue immediately C-terminal to the tyrosine is discussed in relation to the autophosphorylation properties of the regulatory loop regions of the insulin and epidermal growth factor receptor kinases. The data further suggest that receptor tyrosine kinase active sites and their substrate targets act in concert to ensure that specific downstream effects are activated.

Amino Acid Sequence↗
PubMedDate not supplied

The microanatomy of the alveolar duct of the human lung imaged by confocal microscopy and visualised with computer-based 3D reconstruction.

The most widely accepted model of human lung alveolar duct systems is that they are constructed from central helical fibres between the turns of which lie alveolar opening. Experimental difficulties of handling and sectioning lung tissue have made it difficult to confirm this. Confocal laser scanning microscopy (CLSM) was therefore used to generate optical serial sections of the lung that were reconstructed in three dimensions and displayed using volume rendering techniques. From images of the reconstructions, a new structure is proposed in which alveolar ducts consist of collections of connected oval, twisted loop structures with eccentric openings.

Adult↗
PubMed1993

Assessment of the influence of subacute phenobarbitone administration on multi-tissue cell proliferation in the rat using bromodeoxyuridine immunocytochemistry.

The effects of daily administration of phenobarbitone on the mitotic rates of several tissues were investigated by bromodeoxyuridine (BrdU) immunocytochemistry. Phenobarbitone (80 mg/kg per day) was dosed to AP Wistar male rats for up to 7 days and BrdU (10 mg/ml) was given by infusion at a rate of 10 microliters/h via subcutaneously implanted osmotic minipumps for 2 days prior to necropsy on days 1, 2, 3, 5 and 7. BrdU-labelled nuclei were visualised by peroxidase-antiperoxidase immunocytochemistry and counts of the numbers of labelled cells (labelling index, LI%) made from at least 1000 cells per tissue section(s). The LIs of several tissues (testis, adrenal cortex and medulla, kidney distal convoluted tubule and exocrine pancreas) showed no statistical difference by comparison with controls. Several tissues exhibited characteristic responses to phenobarbitone administration. Pituitary and endocrine pancreas LIs were decreased while those of thyroid, liver and kidney proximal convoluted tubule were increased. The pattern of LI increase was unique to each tissue with liver (median and lateral lobes) increased two-fold on day 3 and returning to control levels thereafter while kidney proximal tubule LI rose gradually with time and remained elevated on day 7. Thyroid LI on day 1 was almost double that of day 0 control and increased steadily thereafter. These data illustrate the varied responses of different tissues to phenobarbitone exposure, namely, depression and stimulation of mitosis. The causation of these functional changes is discussed in relation to direct and indirect effects on functional parameters, especially enzyme induction, alterations in hormonal and growth factor status and receptor regulation.

Adrenal Glands↗