Cloning of a cDNA encoding a 3-dehydroquinate synthase from a higher plant, and analysis of the organ-specific and elicitor-induced expression of the corresponding gene

cDNA clones for all enzymes of the prechorismate pathway of higher plants have previously been cloned, with the exception of the second enzyme of the pathway, 3-dehydroquinate synthase. Here we describe the isolation of a cDNA encoding a 3-dehydroquinate synthase from tomato which was identified by complementing a 3-dehydroquinate synthase-deficient Escherichia coli strain with a tomato cDNA library. The deduced amino acid sequence contains a putative N-terminal plastid-specific transit peptide, and the sequence of the mature enzyme resembles those of the corresponding bacterial enzymes more than of the fungal enzymes. Sequence identity was even higher between the tomato and E. coli sequences than between the E. coli and other known bacterial sequences. The abundance of 3-dehydroquinate synthase transcripts differ in the organs of tomato plants analyzed. In cultured tomato cells, the abundance of 3-dehydroquinate synthase transcripts increased 9-fold within 4 to 5 h of elicitor treatment.

A novel model system for the study of experimental guided bone formation in humans

The aim of the present experiment was to test a novel model system, designed to obtain human specimens of regenerated and also newly regenerated jaw bone, for the study of the biological events under a variety of conditions. Following information and disclosure of possible risks associated with a minor oral surgical procedure, 9 systemically healthy subjects (5 men, 4 women, mean age 31.7 years) signed consent forms and volunteered to participate in this study. Hollow test cylinders with an outer diameter of 3.5 mm, an inner diameter of 2.5 mm, and 4 mm in height were used. They were manufactured from commercially pure titanium and exhibited a highly polished inner surface and a titanium plasma sprayed outer rough surface. A mucoperiosteal flap was raised in the retromolar area of the mandible corresponding to standard retrained third molar surgery. Following flap reflection a standardized hole was drilled through the cortical bone into the bone marrow using round burs. The congruent test cylinders were firmly placed into the prepared bony bed yielding primary stability. One-and-a-half to 2 mm of the test device were submerged below the level of the surrounding bone, while the remainder surpassed the level of the bone surface. The bone-facing end of the cylinder was left open, while the coronal soft tissue facing end was closed by an ePTFE-membrane. The flap was sutured to obtain primary wound closure. In order to prevent infection, penicillin was prescribed systemically and oral rinses of chlorhexidine were administered. After 2, 7, and 12 weeks one test device including the regenerated tissue was surgically harvested, while after 16, 24 and 36 weeks respectively, 2 devices were harvested and processed for soft or hard tissue histology or histochemistry. The two surgical procedures and the presence of the test cylinders during the time of healing were well tolerated by the volunteers. In all 9 subjects generated tissue could successfully be harvested. The tissue generated after 2 and 7 weeks presented with a cylindrical shape, whereas the specimens harvested at 12 weeks and thereafter resembled the form of an hourglass. Specimens of 12 weeks and less regeneration time were almost entirely comprised of soft tissue, while specimens with regeneration time of 4 months and more were composed of both soft and increasing amounts of mineralized tissue. It is concluded that the presented model system is suitable to study temporal dynamics and tissue physiology of bone regeneration in humans with minimal risk for complications or adverse effects to the volunteers.

Suicidal behavior in Swiss students: an 18-month follow-up survey

Suicidal behavior and its relationship with other mental disturbances was assessed in an epidemiological study of 1937 Swiss adolescents aged 14 to 19 years. During the most recent 12 months, 27.5% of the females and 16.1% of the males reported suicidal ideation, while 3.3% of the girls and 1.0% of the boys reported suicidal ideation. Suicidality was significantly correlated with physical and mental impairment, alcohol and drug abuse. Of the total epidemiological sample, 475 students (24.5%) were reassessed 12 and 18 months later. Of this follow-up sample, 37 females (12.4%) and 10 males (5.6%) described suicidal ideation as a continuing problem. They revealed significantly more psychiatric symptoms than nonpersistent ideators. Three girls (1.0%) and one boy (0.6%) reported suicide attempts during the follow-up period of 18 months. Only one out of six of the ideators of both sexes received psychiatric treatment. The findings indicate that transient suicidal ideation is common in adolescents. Persistent suicidal behavior appears to be a sign of severe social and psychological disturbances and is associated with serious physical and mental impairment. There is a high risk of completed suicide for youths who demonstrate persistent suicidal ideation, and far more substantial prevention efforts should be designed and implemented to address the circumstances of these youths.

Relationship between disturbed eating behavior and other psychosomatic symptoms in adolescents

BACKGROUND

There has been relatively little research on subthreshold eating disorders and factors which might promote their transition to eating disorders.

METHODS

A sample consisting of 1,944 Swiss adolescents of both sexes, 14-19 years of age, was investigated for eating behavior (EAT-26), psychological (SCL-90-R) and physical symptoms (GSCL-C). In addition, the relationship between eating behavior and other psychosomatic symptoms was analyzed.

RESULTS

The results revealed significantly higher scores for females than males on all except one scale of the questionnaires. Three categories of disturbed eating behavior based on the EAT scores were described: EAT 0-9 = not disturbed (77.5% girls, 93.1% boys), EAT 10-19 = moderately disturbed (14.1% girls, 5.5% boys), and EAT > or = 20 = severely disturbed (8.3% girls, 1.5% boys). With regard to the three aspects, eating habits, psychosomatic symptoms and suicidality a significant correlation between disturbed eating behavior and concurrent psychological and physical symptoms was found in female but not in male subjects.

CONCLUSIONS

The results emphasized that disordered eating behavior has to be seen as part of a broader psychopathological syndrome, especially in young women.

Enzymatic properties of chorismate synthase isozymes of tomato (Lycopersicon esculentum Mill.)

Three plastidic chorismate synthase isozymes (CS1, CS2 and CS2 delta) of tomato were identified by isolation of the corresponding cDNAs. These three cDNAs are derived from only two genes (LeCS1 and LeCS2). This additional complexity results from differential splicing of the primary transcript of one of the genes (LeCS2) giving rise to two different transcripts (CS2 and CS2 delta transcripts). All three isozymes were individually expressed in Escherichia coli both as precursor proteins with N-terminal transit peptides and as mature proteins. Only the mature but not the precursor isozymes CS1 and CS2 were enzymatically active. The enzyme CS2 delta was unstable in E. coli. Both CS1 and CS2 were purified to near homogeneity and their enzymatic properties were analyzed. They differ substantially in their Km values for the substrate 5-enol-pyruvylshikimate 3-phosphate (11 and 80 microM for the mature forms of CS1 and CS2, respectively). The two isozymes appear to be active only as oligomers, and the potential physiological implications of this result are discussed.

[Anomalous origin of the left coronary artery from the right sinus of Valsalva with acute symptoms]

The case of a 52-year-old man with an anomalous origin of the left coronary artery from the right sinus of valsalva coursing between the aorta and pulmonary trunk is reported with an acute myocardial ischemia. He had an additional high-grade main-stem stenosis in the course behind the pulmonary artery. The anatomical variants, clinical significance, and cause of ischemia are discussed. Also, technical considerations in both diagnosis and management are given.

Pharmacokinetics and metabolic pattern after intravenous infusion and oral administration to healthy subjects

Meloxicam [4-hydroxy-2-methyl-N-(5-methyl-2-thiazolyl)-2H- 1,2-benzothiazine-3-carboxamide-1,1-dioxide] is a new nonsteroidal antiinflammatory drug belonging to the enolic acid group. In a crossover study, 30 mg 14C-labeled meloxicam was administered to four male healthy volunteers as a short-term infusion and as an oral solution. The objectives of the study were to determine the mode of elimination, the excretion balance, the in vivo binding characteristics to serum proteins, and to investigate the metabolic pattern in plasma, urine, and feces. A comparison of plasma concentration measurements of unchanged drug by a specific HPLC assay and total radioactivity by liquid scintillation counting revealed a very close conformity. Over 90% of the plasma radioactivity was represented by unchanged drug. Its terminal and dominant half-life of elimination from plasma, as determined from plasma and urinary data in this study, ranged from 12 to 17 hr in the volunteers. The serum protein binding of the radioactivity from in vivo samples was very high (99.1-99.7%). The excretion balance was complete after 6 days. Average urinary excretion of 14C-radioactivity accounted for 43% of the dose, with the remainder appearing with the feces. Meloxicam was extensively metabolized, with only traces of the drug appearing unchanged in urine and feces. The main metabolites were formed by hydroxylation and further oxidation of the methyl group of the thiazolyl moiety. In addition, two further metabolites were found, particularly in urine. Altogether, > 95% of the dose excreted could be accounted for by the metabolites identified or the parent compound itself.

Meloxicam: metabolic profile and biotransformation products in the rat

1. The metabolic fate of 14C-labelled meloxicam was investigated in the urine and bile of rat following oral and intraduodenal administration. Structural elucidation of metabolites was performed by nuclear magnetic resonance, mass spectrometry (electron impact and fast atom bombardment). 2. A mean total of 76.3% 14C-radioactivity was recovered in urine over 96 h, with the remainder in the faeces. The metabolic pattern in the excreta was independent of dose (1 versus 10 mg/kg) and collection period (0-8 versus 24-48 h). In bile one of the main metabolites was absent. 3. Meloxicam underwent extensive metabolism with only small amounts of unchanged drug recovered in the urine (< 0.5%) or bile (4.5%). Principal routes of biotransformation were: oxidation of the 5-methyl group of the N-heteroaryl-carbamoyl side chain to yield the 5'-hydroxymethyl derivative (33% of metabolites in urine, 22% in bile) and the 5'-carboxy derivative (16% in urine, 49% in bile). Oxidative cleavage of the benzothiazine-ring yielded an oxamic acid metabolite in urine (23.5%), which was not present in bile. 4. The introduction of a methyl-group into the N-heteroaryl-carbamoyl side chain increased lipophilicity and facilitated metabolic excretion compared with structurally related compounds.

Physiological traits associated with success of Candida albicans strains as commensal colonizers and pathogens

DNA fingerprinting with the moderately repetitive sequence Ca3 has repeatedly identified groups of genetically similar strains of Candida albicans that are more frequently isolated than other groups of strains from human hosts in a geographical locale. Members of these groups are found in approximately 30% of healthy individuals and in up to 70% of patients suffering from candidiasis. The high prevalence of these strains implies that they are more successful in colonizing human hosts and in causing disease than other strains (J. Schmid, Clin. Adv. Treatment Fungal Infect. 4(6):12-16, 1993). In the present study, we have compared one such group of highly prevalent strains with other strains from the same locale to identify physiological traits a larger number of chemicals than other strains in a resistogram assay. When resistance to individual chemicals used in the resistogram assay was analyzed, strains from the group of highly prevalent strains were significantly more often resistant to boric acid, cetrimide, chlorhexidine, 5-fluorocytosine, and high sodium chloride concentrations than other strains. Strains from the group of highly prevalent strains also adhered significantly (1.5 times) better to saliva-coated surfaces than did other strains. Because members of highly prevalent groups of strains are the most common infectious agents in candidiasis, these physiological traits may be involved in determining not only the success of C. albicans in colonizing human hosts in general but also its ability to cause disease. Sodium chloride resistance and increased adherence were also associated with infectious isolates outside the group of highly prevalent strains, indicating that they may be of particular importance in pathogenesis.

Cloning and characterization of a heterologously expressed bifunctional chorismate synthase/flavin reductase from Neurospora crassa

Activities of all chorismate synthases (CS) so far analyzed are absolutely dependent upon reduced flavin. For monofunctional CSs, which represent the only class of CSs that have yet been cloned, the flavin must be reduced either (photo-)chemically or by a separable flavin reductase (FR) for in vitro activity. Neurospora crassa CS, in contrast, possesses an intrinsic FR activity and represents the only firmly established member of a bifunctional class of CSs. To better understand this bifunctional protein, a cDNA from an N. crassa expression library encoding a 46.4-kDa protein was cloned by complementation of the CS-deficient Escherichia coli strain AB2849. The deduced amino acid sequence was highly similar (79%) to a previously isolated Saccharomyces cerevisiae CS. The N. crassa sequence was unequivocally shown to encode the bifunctional CS/FR by analysis of the purified protein expressed in E. coli. Based on sequence comparisons with known monofunctional CSs, two regions of 18 internal residues and 29 C-terminal residues unique to N. crassa CS were deleted, and the constructs were also expressed in E. coli. The presence of these regions was found not essential for complementation of the CS- phenotype of E. coli strain AB2849. Although a 3.5-fold decline in specific activity of the purified CS from cells expressing the C-terminal deletion construct was observed, bifunctional activity was not eliminated. These data strongly suggest that the domain(s) responsible for reduction of flavin lie(s) within regions in which homology is also shared among monofunctional CSs.

Organ-specific differences in the ratio of alternatively spliced chorismate synthase (LeCS2) transcripts in tomato

The primary transcript of one of the two chorismate synthase genes (LeCS2) of tomato is differentially processed due to an alternative splicing of the third intron. A novel observation was made when the abundances of the two LeCS2-specific transcripts in different organs were analysed. The ratio of these two transcripts differs in RNA populations from different organs. Possible explanations for this finding and its potential physiological impact for plant metabolism are discussed.

Metabolism of pimobendan in long-term human hepatocyte culture: in vivo-in vitro comparison

The aim of this study was to investigate further the potential of a new hepatocyte culture based on the hypothesis that liver cells in an appropriate in vitro environment (immobilizing gel technique) maintain high metabolic activity comparable with that in vivo. Pimobendan (UD-CG 115), a pyridazinone derivative, is a cardiotonic vasodilator that increases myocardial contractility through calcium sensitization and relaxation of vascular smooth muscle, probably due to phosphodiesterase inhibition. In man, pimobendan is O-demethylated to UD-CG 212. This latter is metabolized to O- and N-glucuronides. Pimobendan itself is also glucuronidated to a N-glucuronide. Human hepatocytes immobilized in collagen gel were incubated with pimobendan to investigate their metabolic activity in the long-term and to compare the results to the data from clinical trials. 14C-labelled pimobendan was incubated at two concentrations (10 and 100 microM) at day 3, 11 and 22 of culture, and samples were analysed after 4, 24 and 48-h incubation. Metabolic patterns were evaluated by hplc with radioactivity-, diode array-, and mass spectral-detection. In vitro, pimobendan was O-demethylated and subsequently O-glucuronidated. The rate of metabolism of pimobendan could be maintained in this culture system for > 3 weeks. However, the relative amount of a putative N-glucuronide under in vitro conditions was lower than in vivo.

Only the Mature Form of the Plastidic Chorismate Synthase Is Enzymatically Active

Coding regions of a cDNA for precursor and mature chorismate synthase (CS), a plastidic enzyme, from Corydalis sempervirens were expressed in Escherichia coli as translational fusions to glutathione-S-transferase. Fusion proteins were purified, and precursor and mature forms of CS were then released by proteolytic cleavage with factor Xa. Although mature CS was enzymatically active after release, activity could be detected neither for the precursor CS nor for corresponding glutathione-S-transferase fusion proteins. In contrast, two other shikimate pathway enzymes (shikimate kinase and 5-enol-pyruvylshikimate-3-phosphate synthase) have previously been shown to be as enzymatically active as their respective higher molecular weight precursors. By expression of unfused, mature CS from C. sempervirens in E. coli, it was possible to obtain large quantities of enzymatically active CS protein compared to yields from plant cell cultures. Expression levels in E. coli approached 1% of total soluble protein. No differences were found between authentic CS isolated from cell cultures and CS expressed in and purified from E. coli, which made possible a more detailed biochemical characterization of CS. Quaternary structure analysis of the purified mature CS indicated that the enzyme exists as a dimer, in contrast to the active tetrameric structures determined for E. coli and Neurospora crassa enzymes.

Evidence for nosocomial transmission of Candida albicans obtained by Ca3 fingerprinting

The moderately repetitive sequence Ca3 was used to fingerprint Candida albicans isolates from 32 patients hospitalized for more than 3 days, 17 recent admissions or outpatients, and 8 recently readmitted patients and 10 commensal isolates from the community in Wellington, New Zealand, plus isolates from 21 hospitalized patients, 26 outpatients or recent admissions, 4 recently readmitted patients, and 10 healthy individuals in the community in Auckland, New Zealand. In Wellington, isolates from patients hospitalized in Wellington Hospital for more than 3 days were genetically significantly less diverse than were isolates from outpatients or recent admissions or isolates from healthy individuals in the community. In addition, two clusters of genetically similar strains were isolated from hospitalized patients significantly more often than from other individuals. These observations provide evidence (albeit indirectly) for nosocomial transmission of hospital-specific C. albicans strains. In contrast, no indication of hospital-specific transmission of C. albicans was found in Auckland Hospital. Since these results were obtained under conditions in which no candidiasis outbreak occurred in either hospital, they also suggest that Ca3 fingerprinting may be a useful tool in preventive nosocomial infection control programs, allowing assessment of the extent of C. albicans transmission occurring in a hospital.

Transcranial magnetic stimulation of the trigeminal nerve: intraoperative study on stimulation characteristics in man

We studied responses from the masseter and nasalis muscles following magnetic stimulation (magStim) and compared these responses with those obtained by direct electrical stimulation of the trigeminal (NV) and facial (NVII) nerve near the root exit zone during microvascular decompression operations of NVII. We found that (1) magStim threshold to excite the nerve is high for NV and low for NVII; (2) excitation of all motor fibers is impossible for NV, and easy for NVII; (3) optimal coil placement is critical for NV, but not critical for NVII; and (4) between and within subjects, the excitation site is variable on NV, but stable on NVII. We estimated that the anatomical location of magStim to be either within or outside the cerebrospinal fluid for NV, and to be in the labyrinthine segment of the facial canal for NVII. Physical models explain and clinical lesion models support these differences found between NV and NVII.

Temporally distinct accumulation of transcripts encoding enzymes of the prechorismate pathway in elicitor-treated, cultured tomato cells

The accumulation of phenylalanine-derived phenolic compounds is a well-known element of a plant's defense in response to pathogen attack. Phenylalanine, as well as the other two aromatic amino acids, tyrosine and tryptophan, is synthesized by way of the shikimate pathway. The first seven steps of the shikimate pathway (the prechorismate pathway) are common for the biosynthesis of all three aromatic amino acids. We have studied transcript levels of six genes--i.e., two 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase genes, one shikimate kinase gene, one 5-enolpyruvylshikimate 3-phosphate synthase gene, and two chorismate synthase genes--corresponding to four steps of the prechorismate pathway, in cultured tomato cells exposed to fungal elicitors. The abundance of transcripts specific for some of these genes increased 10- to 20-fold within 6 h after elicitor treatment, as did the abundance of phenylalanine ammonialyase-specific transcripts and the synthesis of ethylene. Interestingly, transcript accumulation occurred more rapidly for shikimate kinase than for the enzymes preceding or following it in the prechorismate pathway. Neither the inhibition of ethylene biosynthesis by aminoethoxyvinylglycine nor inhibition of phenylalanine ammonia-lyase (EC 4.3.1.5) activity by 2-aminoindan-2-phosphonic acid affected the time course or extent of transcript accumulation. Thus, the increased demand for phenylalanine in the phenylpropanoid pathway required after elicitor treatment appears to be met by increased de novo synthesis of its biosynthetic enzymes.

Temporal dynamics of healing in rabbit cranial defects using guided bone regeneration

PURPOSE

The objective of this study was to histologically evaluate the early stages of bone regeneration using rabbit calvaria defects in conjunction with guided tissue regeneration.

MATERIALS

A semilunar cutaneous-periosteal flap was raised on the forehead of four rabbits exposing the top of the skull. A standardized transosseous skull defect (> or = 15 mm in diameter) was made in the area of the right parietal bone with a rotating round bur. Care was taken not to damage the underlying dura. A flat expanded polytetrafluoroethylene (ePTFE) membrane was placed to cover the defect. The membrane was tightly adapted, extending at least 4 mm onto intact bone, and the flap was sutured. One, 2, 3, and 5 weeks later, the specimens were removed and processed using standard, undecalcified, hard-tissue histologic techniques. Contact radiographs were also taken.

RESULTS

Bone growth increased with time, starting at the borders of the defect. At 1 week, trabeculae of woven bone grew into the highly vascularized loose connective tissue occupying the defect. Two weeks postsurgery, isolated islands of new bone were detected in this connective tissue. Subsequently, neighboring small islands merged to form large islands. In later stages, the primary trabeculae of woven bone were reinforced by layers of regularly deposited lamellar bone.

CONCLUSION

Rabbit calvaria defects treated by guided tissue regeneration heal by ingrowth of woven bone from the defect margins and by formation of bony islands within the defect area. Bone healing showed the histophysiological characteristics of intramembranous bone.

Development under population pressure and shortage of resources--an alternative path to the demographic transition

As a result of two closely related problems, namely the population problem in almost all parts of the world and the serious effects on the environment, thinking relating to development has taken a new direction. Development is more and more closely linked to the question of population and the form of production which to a great extent affects technology and resources.

Structural and catalytic properties of the four phenylalanine ammonia-lyase isoenzymes from parsley (Petroselinum crispum Nym.)

Near-full-length cDNAs for the four phenylalanine ammonia-lyase (PAL) isoenzymes in parsley (Petroselium crispum Nym.) were cloned and the complete amino acid sequences deduced. Fusion proteins with glutathione S-transferase were expressed in Escherichia coli, purified and cleaved. All of the resulting phenylalanine ammonia-lyase proteins, as well as the fusion proteins, were catalytically active. The turnover number of one selected isoenzyme, PAL-1, was estimated to be around 22 s-1 for each active site. In contrast to a certain degree of differential expression in various parts of parsley plants, the four phenylalanine ammonia-lyase isoenzymes exhibited very similar apparent Km values for L-phenylalanine (15-24.5 microM) as well as identical temperature (58 degrees C) and pH (8.5) optima. All of them were competitively inhibited by (E)-cinnamate with similar efficiency (Ki values: 9.1-21.5 microM), lacked cooperative behaviour, and accepted L-tyrosine as a substrate with low affinity (Km values: 2.6-7.8 mM). These results suggest that the occurrence of multiple gene copies has a function other than encoding isoenzymes with different enzyme kinetic properties.

Membrane permeability is unnecessary for guided generation of new bone. An experimental study in the rabbit

The aim of this investigation was to test the hypothesis that membrane permeability is necessary in bone formation using the principle of guided tissue regeneration. On the forehead of 8 rabbits, titanium test cylinders were anchored in the calvaria. These cylinders were either covered by an expanded polytetrafluoroethylene (ePTFE) membrane generating a chamber for bone formation or they were sealed off by cast titanium. The implanted cylinders were covered by resuturing the periosteum and the cutaneous flap. After 8 months of healing, new bone had formed in all cylinders in all animals irrespective of whether the chamber for bone formation was sealed off by cast titanium or the ePTFE membrane. Based on these results, we conclude that permeability of the membrane is not necessary in the guided generation of new bone.

Assay of zatebradine in plasma by fully automated sample clean-up, capillary gas chromatography and ammonia chemical ionisation mass spectrometry

A method has been developed for the measurement of zatebradine (UL-FS 49), a heart-rate lowering drug, suitable for the treatment of stable angina pectoris. The method comprises a fully automated liquid-solid extraction using a Zymark Benchmate, a capillary gas chromatography and ammonia chemical ionisation (CI) mass spectrometry using hexadeuterated zatebradine for the internal standard. The assay has a mean between-batch imprecision of 4.9% and a mean inaccuracy of 1.5%. The calibration curve covers the range of 1-30 ng/ml. About 60 samples can be handled per day. The assay has been successfully applied to human pharmacokinetic studies.

[The introduction of paddocks in circus elephant husbandry]

The guidelines for the keeping, the education and the using of animals in circuses and similar institutions, which are made in connection with the law for prevention of cruelty to animals, claim to keep elephants daily one hour unshackled in the group in a paddock. This paper deals with the effect of the paddock to the social, the play, and the comfort behaviour, and the stereotyped movements of circus elephants. Basically for the behaviour of kept elephants are results of observations in nature. A pilot study with 29 elephants in four circuses showed that the paddock enabled the elephants to carry out social and comfort behaviour more frequently than in the shackled keeping. The stereotyped movements were nearly absent by keeping the elephants in the paddock. If they keep shackled, this behaviour anomaly will take up much time.