[Motility disorders of the esophagus]. / Motilitätsstörungen des Ösophagus.

Motility disorders of the esophagus comprise a heterogeneous spectrum of diseases. Primary malformations of the esophagus are now amenable to improved surgical and gastroenterological therapies; however, they often lead to persistent long-term esophageal dysmotility. Achalasia originates from impaired relaxation of the gastroesophageal sphincter apparatus. Systemic diseases may give rise to secondary disorders of esophageal motility. A number of visceral neuromuscular disorders show an esophageal manifestation but aganglionosis rarely extends into the esophagus. The growing group of myopathies includes metabolic and mitochondrial disorders with increasing levels of genetic characterization and incipient emergence of therapeutic strategies. Esophagitis with an infectious etiology causes severe dysmotility particularly in immunocompromised patients. Immunologically mediated inflammatory processes involving the esophagus are increasingly better understood. Finally, rare tumors and tumor-like lesions may impair esophageal motor function.

[Sonographic diagnostics of proximal humerus fractures in juveniles]. / Sonographische Diagnostik der subkapitalen Humerusfraktur im Wachstumsalter.

AIM OF THE STUDY: The exact determination of the extent of deformities in juvenile proximal humerus fractures is difficult with plain x-rays. The aim of this study was to find out whether proximal humerus fractures can be diagnosed and the extent of the deformity can be detected by ultrasonography. PATIENTS AND METHODS: In a prospective, multicentre trial children aged 0-12 years with suspected proximal humerus fractures were examined. Initially a standardized sonographic evaluation was performed and the extent and the direction of the deformity were determined. The recommended treatment was noted. Afterwards standard x-rays were taken and the results of both diagnostic procedures were compared. RESULTS: A total of 33 children were examined, 14 male and 19 female, with a mean age of 7.6 years. In the ultrasound examination 17 out of 18 proximal humerus fractures were detected. In comparison to x-ray diagnostics ultrasonography proved to have a sensitivity of 94% and a specificity of 100%. In 16 cases ultrasonography gave a better result than x-ray imaging and x-ray was better in 5 cases. CONCLUSION: Ultrasonography is suitable for detection and exclusion of fractures and better than x-ray diagnosis for evaluation of the type and direction of deformations of proximal humerus fractures.

Polyamines: essential factors for growth and survival.

Polyamines are low molecular weight, aliphatic polycations found in the cells of all living organisms. Due to their positive charges, polyamines bind to macromolecules such as DNA, RNA, and proteins. They are involved in diverse processes, including regulation of gene expression, translation, cell proliferation, modulation of cell signalling, and membrane stabilization. They also modulate the activities of certain sets of ion channels. Because of these multifaceted functions, the homeostasis of polyamines is crucial and is ensured through regulation of biosynthesis, catabolism, and transport. Through isolation of the genes involved in plant polyamine biosynthesis and loss-of-function experiments on the corresponding genes, their essentiality for growth is reconfirmed. Polyamines are also involved in stress responses and diseases in plants, indicating their importance for plant survival. This review summarizes the recent advances in polyamine research in the field of plant science compared with the knowledge obtained in microorganisms and animal systems.

Evaluation of cast wedging in a forearm fracture model.

BACKGROUND: In paediatric traumatology fractures are commonly treated with a cast. In this course cast wedging is sometimes performed aiming to reduce the fracture angulation. However, the impact of various factors and measures such as cast material, optimal position of the wedge and wrist position were not assessed in a systematic manner. METHODS: A laser supported model was developed to evaluate the biomechanical processes of cast wedging manoeuvre in a model of a distal diaphyseal forearm fracture. Consecutive measurements were performed to find out the influence of wedge position, cast material and wrist position. FINDINGS: The result of the manoeuvre was revealed to be independent of the cast material (plaster of Paris vs. synthetic cast) used. The optimal position for placing the wedge was shown to be on the concave side of the cast at the level of the fracture. The result of a cast wedging manoeuvre in a dorsally displaced forearm fracture can be optimized with the wrist held in extension. INTERPRETATION: The cast wedging model is not a meticulous copy of the human anatomy but it allows some basic studies on cast wedging technique. The results that can be achieved are similar to the experiences of practical paediatric traumatology. Furthermore the present model may be beneficial for use in education and training programs.

Specific association of transcripts of tbzF and tbz17, tobacco genes encoding basic region leucine zipper-type transcriptional activators, with guard cells of senescing leaves and/or flowers.

Induction by low temperature is a common feature of the lip19 subfamily members of the basic region leucine zipper gene family in plants. Here, we characterize two tobacco (Nicotiana tabacum) genes, tbzF and tbz17, belonging to the lip19 subfamily, whose gene products, TBZF and TBZ17, show 73% identity and are located in nuclei. They preferentially bind to DNA fragments spanning A-box/G-box and C-box/G-box hybrid motifs and show transactivation activity in cobombarded tobacco BY-2 cells, indicating they function as transcriptional activators. Transcripts of tbzF were detected at a high level in senescing leaves and flowers. In contrast, tbz17 transcripts could be shown to accumulate in aged leaves but not in flowers. In situ hybridization analysis revealed transcripts of tbzF and tbz17 to be predominantly located in guard cells and vascular tissues of senescing leaves. These results suggest that TBZF and TBZ17 are both involved in controlling gene transcription related to functions of guard cells in senescing leaves and that TBZF bifunctionally acts in floral development.

cDNA cloning of cytoplasmic ribosomal protein S7 of winter rye (Secale cereale) and its expression in low-temperature-treated leaves.

A cDNA clone (ScRPS7) encoding the cytoplasmic ribosomal protein S7 was isolated from a rye leaf cDNA library and sequenced. The deduced protein of 192 amino acids with M(r) 22189 shows identity of 52% or 47%, respectively, relative to S7 proteins of human or yeast. A RPS7 mRNA accumulation is higher in the meristematic zone at the leaf base than in the non-meristematic middle and upper section of leaves. Short periods of cold stress sharply reduce the mRNA level while leaves of cold hardened plants contain normal levels of ScRPS7 transcripts.

Diverse response of rice and maize genes encoding homologs of WPK4, an SNF1-related protein kinase from wheat, to light, nutrients, low temperature and cytokinins.

The wheat gene WPK4 encodes a 56-kDa protein kinase that belongs to group 3 of the SNF1-related protein kinase family (SnRK3), and is up-regulated by light and cytokinins and down-regulated by sucrose. In order to determine whether or not this particular regulation pattern is general among plant species, we isolated and characterized homologous genes from rice and maize. Two rice genes, OsPK4 and OsPK7, encode proteins comprising 508 and 520 amino acids, and show, respectively, 75% and 76% sequence similarity to WPK4. OsPK4 and OsPK7 proteins produced in Escherichia coli were able to phosphorylate themselves and myelin basic proteins, the reaction requiring magnesium and/or manganese ions. Transcripts of OsPK4 were detected in all tissues tested, and amounts were increased upon illumination, nutrient deprivation and treatment with cytokinins. In contrast, transcripts of OsPK7 were not found in any tissues except in mature leaves at low levels, and did not accumulate under any of the stress conditions examined. A maize gene, ZmPK4, encodes a protein with 518 amino acids that shows 74% similarity to WPK4. Its transcripts were constitutively expressed in all tissues, regardless of light, nutrient and cytokinin status, but were increased upon exposure to low temperature. These results indicate that, despite the sequence similarity between their products, genes for SnRK3 proteins are differentially regulated in response to environmental stimuli.

Involvement of a MAP kinase, ZmMPK5, in senescence and recovery from low-temperature stress in maize.

Four species of protein kinase were identified in senescent maize leaves using a gel assay for kinase activity with myelin basic protein (MBP) as the substrate. Most of these kinases were also found in healthy green leaves that had been exposed to low-temperature stress (5 degrees C) and then returned to 25 degrees C. A 41-kDa protein was activated in senescent leaves, whereas a 45-kDa protein was activated 3 h after up-shift from 5 degrees C to 25 degrees C as well as in senescent leaves. A 39-kDa protein was activated by cold stress. The other two proteins, of 35 kDa and 52 kDa, constitutively phosphorylated MBP during senescence and temperature up-shift. Judging from their molecular masses, cation requirements and substrate specificities, it seemed likely that the 39-kDa, 41-kDa and 45-kDa proteins represented mitogen-activated protein kinases (MAPKs). Subsequently two MAPK cDNAs were isolated from a cDNA library constructed using mRNAs from senescent leaves. Northern analysis showed that the transcript corresponding to one of the cDNAs, designated ZmMPK5, accumulated in healthy leaves 3 h after the up-shift to 25 degrees C as well as in senescent leaves, suggesting that the 45-kDa protein kinase is encoded by ZmMPK5. Western analysis using an antiserum against the C-terminal region of ZmMPK5 showed that the level of the ZmMPK5 protein increased in senescent leaves. These results indicate that a 45-kDa MAPK is involved in the process of senescence and in recovery from low-temperature stress in maize plants.

Two maize genes encoding omega-3 fatty acid desaturase and their differential expression to temperature.

We have isolated two maize cDNAs and the corresponding genes encoding fatty acid desaturase with Arabidopsis thaliana FAD7 gene as a probe. They shared almost 90% identity at DNA sequence level. Northern analysis revealed that both genes are expressed in leaves, but not in roots at normal temperature- and low temperature-growth condition. The overall level of these transcripts are elevated upon exposure to low temperature. The tissue-specific expression and DNA sequence data indicate that both genes encode plastidic omega-3 fatty acid desaturases. One of them is expressed exclusively at normal temperature but not at 5 degrees C, whereas the other is expressed inversely. We, therefore, termed them ZmFAD7 and ZmFAD8, respectively. Among other stresses, high-salt treatment induced the accumulation of the ZmFAD7 and ZmFAD8 transcripts in roots but drought had no effect on their expression. Cycloheximide induced the accumulation of the ZmFAD7 transcript in roots. The genomic clones of ZmFAD7 and ZmFAD8 consist of 8 exons and 7 introns as same as in the cases of A. thaliana FAD7 and FAD8 genes and the sizes of the 6 internal exons were identical among them. A phylogenetic analysis of ZmFAD7, ZmFAD8 amino acid sequences and those originated from other plant species is also presented.

Molecular cloning and partial characterization of a tobacco cDNA encoding a small bZIP protein.

Here we report the isolation of a tobacco cDNA which is a counterpart gene of rice low-temperature-induced lip19. Expression of the gene (termed tbz17) is also positively controlled by low temperature but fairly moderately compared with the low-temperature-responsiveness of rice lip19 and the maize counterpart gene, mlip15. The predicted gene product (termed TBZ17) is a bZIP protein of 145 amino acids and shows about 45% identity with rice LIP19 and maize mLIP15 proteins. DNA binding studies indicate that TBZ17 has quite similar DNA binding characteristics to that of mLIP15. The results suggest that low-temperature-induced gene(s) encoding a DNA binding factor with bZIP motif is omni-present in higher plants.

Cycloheximide induces a subset of low temperature-inducible genes in maize.

To investigate further the signal transduction pathway that mediates the cold-stress response in maize, we isolated a low temperature-inducible cDNA clone (ZmCDPK1) that encodes a calcium-dependent protein kinase. Time-course experiments revealed that the low-temperature induction of ZmCDPK1 precedes that of mlip15, another cold-inducible gene that codes for a DNA-binding protein of the basic region/leucine zipper (bZIP) type, indicating that ZmCDPK1 might be located upstream of mlip15 in the cold-stress signal transduction pathway. We observed that the steady-state mRNA level of mlip15 drastically increased after cycloheximide treatment. In addition to mlip15, cycloheximide elevates the transcript levels of two other low temperature-induced genes, ZmCDPK1, and Adh1, which encodes alcohol dehydrogenase 1. In contrast, the chalcone synthase gene was only inducible by low temperature. The accumulation of the mlip15 transcript at low temperatures and in response to cycloheximide was significantly reduced by pretreatment with a calcium chelator, suggesting that calcium is involved in both cases of mlip15 induction. The signal transduction pathways triggered by low temperature and cycloheximide are discussed in relation to these observations.

Molecular cloning, characterization and expression of an elongation factor 1 alpha gene in maize.

A cDNA (zmEF1A) and the corresponding genomic clone (zmgEF1A) of a member of the gene family encoding the alpha subunit of translation elongation factor 1 (EF-1 alpha) have been isolated from maize. The deduced amino acid sequence is 447 residues long interrupted by one intron. Southern blot analysis reveals that the cloned EF-1 alpha gene is one member out of a family consisting of at least six genes. As shown by northern hybridizations in leaves the mRNA level increases at low temperature whereas time-course experiments over 24 h at 5 degrees C show that in roots the overall mRNA level of EF-1 alpha is transiently decreased. These results indicate that the expression of EF-1 alpha is differently regulated in leaves and roots under cold stress.

A maize DNA-binding factor with a bZIP motif is induced by low temperature.

We have isolated a low temperature-induced maize gene, mlip15, via cross hybridization using rice lip19. The longest cDNA isolated comprised 1179 bp and coded for a 135 amino acid bZIP (basic region/leucine zipper) protein. The gene showed 61.4% and 68.9% identity with the rice gene at the DNA and amino acid sequence levels, respectively, and is distinct from other maize genes that code for bZIP proteins. The level of mlip15 transcript was positively regulated by low temperature in the same way as the lip19 transcript. The levels of the transcript were also strongly increased by salt stress and exogenous abscisic acid, and slightly increased by anaerobiosis, but were not affected by heat shock and drought. The mLIP15 protein and truncated derivatives, produced in rabbit reticulocyte lysates or in an Escherichia coli expression system, were able to bind to a fragment of the wheat histone H3 gene promoter. This binding was diminished by addition of a molar excess of the hexamer sequence 5'-ACGTCA-3' found in the promoter and of the G-box-like sequence, but not by the addition of the ocs sequence or a mutated hexamer sequence. The factor bound to a promoter region of the maize Adh1 gene, expression of which is also induced by low temperature. These results lead to the conclusion that mlip15 is a strong candidate for a low temperature-induced transcription factor in maize.