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Biomedical subjects

M Frey

Publications and source records attributed to M Frey.

At least 55 records · Page 3Linked to original sources
PubMed2001

Evolution of benzoxazinone biosynthesis and indole production in maize.

The synthesis of a diverse spectrum of secondary metabolites has allowed plants to develop sophisticated chemical defense mechanisms. Maize (Zea mays L.), for example, releases a cocktail of volatile compounds when attacked by a caterpillar. These compounds attract a parasitic wasp, which deposits its eggs in the larvae, thereby controlling the population size of the herbivore. Indole, which is part of the cocktail, is produced by an enzyme recruited from primary metabolism. Indole can either function as a volatile signal or be converted by specific cytochrome P450 enzymes into benzoxazinoids, which function as important defense chemicals.

Benzoxazines↗
PubMed2001

Disease expression of Lyme borreliosis in northeastern France.

Since very little is known about the clinical expression of Lyme borreliosis in Western Europe, a 3-year prospective study was conducted that included all patients seen for suspected Lyme borreliosis at the Strasbourg University Hospital in northeastern France. The diagnosis of Lyme borreliosis was made on the basis of the presence of erythema migrans or on the basis of another suggestive clinical manifestation and laboratory confirmation. A total of 132 patients, 70 women and 62 men, mean age 54 years, had Lyme borreliosis according to these criteria. Within this study group, 77% of the patients were regularly exposed to tick bites and 64% could remember one. Erythema migrans, the most frequent clinical manifestation, occurred in 60% of the patients and was the only sign of Lyme borreliosis in 40%. Lymphocytoma and acrodermatitis chronica atrophicans were rare (1 and 3 patients, respectively). Nervous system involvement (mainly radiculoneuropathy), the second most common clinical manifestation, was found in 40% of the patients and was the only sign of Lyme borreliosis in 22%. Musculoskeletal involvement was present in 26% of the patients and was an isolated finding in 14%. During the study period, no patient was diagnosed with Lyme carditis. There was serological evidence of Lyme borreliosis in 75% of the cases and direct evidence of borrelial infection in 10 (7.5%). The results show that the clinical expression of Lyme borreliosis in northeastern France is similar to that in other European countries but different from that in North America.

Adolescent↗
PubMed2001

Two glucosyltransferases are involved in detoxification of benzoxazinoids in maize.

Benzoxazinoids are major compounds involved in chemical defence in grasses. These toxins are stored in the vacuole as glucosides. Two glucosyltransferases, BX8 and BX9, that catalyse this last step of benzoxazinoid biosynthesis have been isolated via functional cloning. No close relative of these maize genes was found among the known glucosyltransferases. The enzymes display a very high degree of substrate specificity. DIMBOA, the major benzoxazinoid in young maize, is the preferred substrate. Both genes are highly expressed in young maize seedlings, the developmental stage with the highest activity of benzoxazinoid biosynthesis. Bx8 is included in the cluster of DIMBOA biosynthesis genes located on the short arm of chromosome 4. Hence, the gene cluster comprises three different enzymatic functions and a complete set of genes for the biosynthesis of DIBOA glucoside. Bx9 mapped to chromosome 1. Expression of Bx8 and Bx9 in Arabidopsis corroborated the potency of the enzymes in detoxification of their substrates. This capacity might have implications for allelopathic interactions.

Base Sequence↗
PubMed2001

[Value of several examination systems in patients with carpal tunnel syndrome. Comparison of Dellon computer-assisted sensation test with Mellesi hand status and Levine examination scheme].

The goal of the presented carpal tunnel syndrome (CTS) follow-up study was to compare the clinical value of the Millesi hand function score with the "Pressure Specifying Sensory Device" (PSSD) introduced by A. L. Dellon using self-administered patient questionnaires. 25 patients (10 male, 15 female) with an electrodiagnostically confirmed CTS were enrolled in this study, performing one preoperative and five postoperative examinations over 24 weeks. 12 of the 25 patients underwent an "open" two-portal carpal tunnel release with two minimal incisions (group OT); the other 13 patients were treated with a two-portal endoscopic carpal tunnel release (group ET). Additionally, in eleven out of the twelve patients of group OT, an epineuriotomy of the median nerve was performed during the same session. Concerning preoperative data of the Millesi score and the PSSD, no statistically significant differences were found between group OT and ET. However, preoperative comparison with the contralateral hand demonstrated a reduction in hand function of 15% and an increase in the pressure perception threshold of 41% compared to normative data could be measured with the PSSD. The subjective functional value of the hand was objectively evacuated using the Levine score. In the second postoperative week, a significant decrease in hand function could be obtained with the Millesi score in group OT. In group ET, the decrease in hand function representing the operative trauma was significantly lower than in group OT. Data of the static one- and two-point pressure perception threshold revealed a statistically significant improvement of the sensibility in both groups. The results of the Millesi score recorded at the last examination in the 24th postoperative week showed an improvement in hand function in both groups compared to preoperative data. Concerning static one- and two-point measurements with the PSSD, distinct improvements compared to the preoperative data could also be detected in both groups although significant differences between group OT and ET were evident: Data of group OT regarding the whole postoperative course demonstrate a continuous improvement in sensibility of the index finger. In contrast, the analysis of the PSSD measurements in group ET revealed an increase in all the parameters starting in the sixth postoperative week and ending with significantly worse static one- and two-point threshold measurements than in group OT. On the other hand, data of self-administered patient questionnaires using the Levine Score revealed significant improvements in hand function and reduction in pain intensity in both groups compared to preoperative results. Differences between both groups at the end of the examination course were not evident. In conclusion, the Millesi hand score with its emphasis on the motor function proved to be a reliable method to record the severity of CTS preoperatively, the severity of the surgical trauma and changes in the course of rehabilitation of the affected hand. A good correlation was found between data obtained with the Millesi Score and the self-administered patient questionnaires according to Levine. But when compared with the PSSD, both methods could not directly document the preoperative status and postoperative changes of the median nerve. Preoperative static two-point pressure threshold measurements with the PSSD confirmed their status as a screening parameter as published by A. L. Dellon. In the postoperative course of group ET, a distinct worsening in the sensibility of the index and little finger could only be detected with the PSSD before the patients noticed the onset of related symptoms.

Adult↗
PubMed2001

Detection of serum autoantibodies to tumor suppressor gene p53 with a new enzyme-linked immunosorbent assay in patients with ovarian cancer.

Sera from 99 ovarian cancer patients were assayed for serum autoantibodies to p53 using a newly developed enzyme-linked immunosorbent assay (ELISA). Results were compared to the investigation using the former ELISA. The incidence of autoantibodies (25%) was lower using the newly developed ELISA as compared to the previous results (41%). The results were consistent in 79% of patients (P < .001). The incidence of autoantibodies was lower in patients with complete remission (19%) as compared to that of patients with recurrence (30%) and before primary surgery (26%). No statistically significant correlation was found among p53 serum autoantibody status and tumor stage, degree of malignancy, histologic subtype, and residual tumor after primary surgery. Use of the newly developed ELISA resulted in a higher consensus between immunohistochemically negative and autoantibody negative cases. Owing to further purifying of the prepared human recombinant p53. the newly developed ELISA seems to be of higher specificity as compared to the former ELISA.

Adenocarcinoma, Clear Cell↗
PubMed2000

An herbivore elicitor activates the gene for indole emission in maize.

Maize and a variety of other plant species release volatile compounds in response to herbivore attack that serve as chemical cues to signal natural enemies of the feeding herbivore. N-(17-hydroxylinolenoyl)-l-glutamine is an elicitor component that has been isolated and chemically characterized from the regurgitant of the herbivore-pest beet armyworm. This fatty acid derivative, referred to as volicitin, triggers the synthesis and release of volatile components, including terpenoids and indole in maize. Here we report on a previously unidentified enzyme, indole-3-glycerol phosphate lyase (IGL), that catalyzes the formation of free indole and is selectively activated by volicitin. IGL's enzymatic properties are similar to BX1, a maize enzyme that serves as the entry point to the secondary defense metabolites DIBOA and DIMBOA. Gene-sequence analysis indicates that Igl and Bx1 are evolutionarily related to the tryptophan synthase alpha subunit.

Animals↗
PubMed2000

Phylogenetic, antigenic and clinical characterization of type 2 BVDV from North America.

Bovine viral diarrhea virus (BVDV) infection continues to have a significant impact upon US cattle producers despite the availability of more than 140 federally licensed vaccines. Detection and control is hampered by viral heterogeneity that results in differences in neutralizing epitopes, cytopathology and virulence. Recently it was found that there are two different genotypes, BVDV1 and BVDV2, among BVDV. BVDV2 isolates make up a significant proportion of the BVDV isolated in North America. Serologically BVDV2 viruses can be distinguished from BVDV1 and border disease viruses. Mab binding also distinguishes between BVDV1, BVDV2 and BDV. Like the BVDV1 viruses, BVDV2 viruses may exist as one of two biotypes, cytopathic or noncytopathic, based on their activity in cultured cells. Cytopathogenic effects on cultured cells does not correlate with virulence in vivo, as BVDV2 associated with hemorrhagic syndrome (HS) are noncytopathic. Variation among BVDV1 and BVDV2 in the 5' UTR is similar. Phylogenetic analysis and differences in virulence suggest that BVDV2 are heterogeneous. Symptoms resulting from BVDV2 infections may range from clinically inapparent to clinically severe. Recently, disease outbreaks associated with acute uncomplicated BVDV infection have been reported in the US and Canada. These outbreaks of clinically severe disease, termed HS, were all associated with viruses from the BVDV2 genotype. Not all BVDV2 isolates cause clinically severe disease. Avirulent BVDV2 isolates do exist and may predominate over virulent BVDV2 in nature. When virulent BVDV2 viruses are inoculated into calves they induce a disease characterized by fever, diarrhea, leukopenia, lymphopenia, neutropenia, thrombocytopenia, and death. Infection with avirulent BVDV2 results in a reduction of luekocytes that may be accompanied by a low-grade fever. These viruses do not cause clinical disease or a clinical leukopenia.

Animals↗
PubMed2000

Adding valproate to lamotrigine: a study of their pharmacokinetic interaction.

The addition of valproic acid (VPA) to a lamotrigine monotherapy regimen (LTG) results in a decrement of LTG clearance. Whether this effect is related to the dose or concentration at steady state (Css) of VPA is yet to be established. This study was conducted to determine whether the dose or Css of VPA were inversely related to LTG clearance in 28 patients with intractable epilepsy who were treated with a combination of LTG and VPA. Correlations between LTG clearance and the dose and Css of VPA and comparisons of LTG clearance during low and high doses of VPA demonstrated that the degree of inhibition of LTG clearance is independent of the dose and Css of VPA.

Adolescent↗
PubMed2000

Elucidating the mode of action of a corrosion inhibitor for iron

Two polymetallic iron(III) complexes 1 and 2 have been synthesised from the known corrosion inhibitor 3-(4-methylbenzoyl)-propionic acid HL1 and their crystal structures determined. Coordination geometries extracted from these structures have been used as the basis for molecular modelling onto idealised iron(III) oxide surfaces as an aid to understanding the efficacy of inhibitors of the 4-keto acid type. The proposed mode of action involves 1,3-bridging didentate coordination of the carboxylate function of L1 to two FeIII ions, hydrogen-bond formation between the 4-keto group of L1 and a bridging surface hydroxy group, as well as close packing of the aromatic end groups, which should generate a hydrophobic barrier on the surface. Adsorption isotherm experiments have been used to compare the strengths of binding of related carboxylic acids onto iron(III) oxide surfaces and indicate that the presence of the 4-keto function leads to the formation of significantly more stable surface complexes.

Journal Article↗
PubMed2000

Electrophysiological correlates of visual impairments after traumatic brain injury.

Our aims were to investigate: (i) the VEP correlates of functional visual impairments following traumatic brain injury (TBI), in particular of the reduced spatial form perception; and (ii) the VEP correlates of visual sustained arousal in TBI patients. We used two approaches: (i) the analysis of latency and amplitude of the peaks; and (ii) the study of the correlations among the latencies of the peaks as a label of temporal synchronization. Thirty-five severe TBI outcome inpatients and 35 matching controls were studied. Pattern-reversal VEPs were recorded at Oz-Fz and Cz-A1, first without counting, then with counting of the reversals. Seven peaks of the waveform at Oz and eight peaks at Cz were measured. We found several differences in amplitude and latency between patients and controls, and between nocount/count. The temporal binding of the peaks within each channel and between the two channels was calculated by correlation matrices, and tested by factor analysis. Results indicated that the synchronization of the peaks within each channel did not differ between patients and controls. The temporal covariation between peaks occurring at Oz and Cz, however, was highly significantly altered in patients. This suggests that visual impairments in TBI patients may be due to a deranged synchronization of the activity of different brain regions.

Adolescent↗
PubMed2000

Role of natural benzoxazinones in the survival strategy of plants.

Benzoxazinoid acetal glucosides are a unique class of natural products abundant in Gramineae, including the major agricultural crops maize, wheat, and rye. These secondary metabolites are also found in several dicotyledonous species. Benzoxazinoids serve as important factors of host plant resistance against microbial diseases and insects and as allelochemicals and endogenous ligands. Interdisciplinary investigations by biologists, biochemists, and chemists are stimulated by the intention to make agricultural use of the benzoxazinones as natural pesticides. These natural products are not only constituents of a plant defense system but also part of an active allelochemical system used in the competition with other plants. This review covers biological and chemical aspects of benzoxazinone research over the last decade with special emphasis on recent advances in the elucidation of the biosynthetic pathway.

Animals↗
PubMed2000

Quantification of functional results after facial burns by the faciometer.

In the present study the faciometer(R) is introduced in order to quantify the ranges of mimic movements observed after surgical treatment of facial burns. This instrument which consists of calipers and an electronic display was introduced in 1994 in order to measure the extent of facial palsy during reconstructive procedures. The study group consisted of 23 patients, who had been operated on for facial burns. The distances between standardised stable and moving points in the face were determined after mimic movements such as lifting of the eyebrows, maximum showing of the teeth and pursing of the lips. These distances were expressed as a percentage of the distance at rest. For comparison the scars were classified according to the Vancouver Scar Scale. In all patients the functional results after burn trauma in the face and, in some cases, asymmetries at rest could be objectified. Depending upon the severity of scarring, the distance between tragus and mouth was shortened between 0 and 19% after maximal showing of the teeth. In general the mouth region showed more functional deficits than the forehead. Comparing different manners of treatment, it could be objectively demonstrated that the results after deep burns requiring skin grafts were worse than those observed after more superficial lesions and other methods of coverage. The application of keratinocytes to close the burn showed highly variable results.

Adolescent↗
PubMed2000

Histomorphology of rabbit thigh muscles: establishment of standard control values.

The thigh muscles of New Zealand White (NZW) rabbits are frequently used in experimental surgery, particularly for evaluation after reinnervation or ischaemia. Although histomorphometric analyses are regularly performed, morphological data for untreated thigh muscles in previously unoperated animals are not available. Specimens from the rectus femoris (RF), vastus medialis (VM) and adductor magnus (AM) muscles from both thighs were harvested in 7 untreated rabbits and were processed for histomorphometric evaluation. The right RF and VM were harvested in a further 5 rabbit hindlimbs after experimental denervation and reinnervation of the contralateral RF and subsequently processed for histomorphometric analysis. Muscle fibre type distribution, diameter and connective tissue content were evaluated on serial transverse cryosections reacted for ATPase and NADH tetrazolium reductase activity and statistical analysis was performed. In all untreated animals RF revealed the highest proportion of type I muscle fibres (right: 8.4+/-4%, left: 11.4+/-4.9%), whereas VM showed the highest percentage of IIa fibres (right: 31.9+/-5.5%, left: 28.3+/-7.8%) and AM the highest proportion of IIb/d fibres (right: 80.5+/-8.6%, left: 84.4+/-6.3%). Fibre type distribution and diameter in rabbits after contralateral experimental operations revealed a statistically significant difference from the data obtained in bilaterally untreated animals. Knowledge of the morphology of untreated muscles is fundamental to the understanding of changes induced by intervention to the ipsi and/or contralateral thigh muscles.

Analysis of Variance↗
PubMed2000

The anatomy of the pectoral nerves and their significance in brachial plexus reconstruction.

Twenty-nine brachial plexuses from 13 embalmed and 5 fresh cadavers were examined under x3.5 loupe magnification to collect systematic and topographic anatomical data regarding the lateral and medial pectoral nerves. Additionally, nerve biopsy specimens were harvested in 5 fresh cadavers to obtain histomorphometric data. In all dissections the pectoral nerves exited at the trunk level as 3 distinct nerves. The superior pectoral nerve (from the anterior division of the superior trunk) commences just distal to the suprascapular nerve and courses laterally to innervate the lateral clavicular portion of the pectoralis major muscle (PM) with 2 to 4 branches. The middle pectoral nerve (from the anterior division of the middle trunk) courses distally and enters the infraclavicular fossa with 2 constant branches. The superficial branch terminates in the medial clavicular and upper sternal parts of the PM. The deep branch always forms a plexus with the medial pectoral or inferior pectoral nerve (from the anterior division of the inferior trunk), which courses at a right angle around the the lateral thoracic artery. From this plexus several branches terminate in the Pm. The branch to the lower aspect of the PM pierces the pectoralis minor muscle in two thirds of cases, whereas it passes its inferior border to reach the lower aspects of the PM with an average length of 15 cm in one third of cases. Knowledge of the detailed anatomy of the pectoral nerves, as outlined in this study, clarifies the obscure anatomic relationship of the lateral and medial pectoral nerves and allows easy intraoperative location of the medial pectoral nerve at the exit of the lateral thoracic artery. The length of the inferior pectoral nerve, the number of motor axons, and the anatomical proximity of this nerve make it an expendable but powerful source of reinnervation to the musculocutaneous nerve in upper brachial plexus injuries.

Adult↗
PubMed2000

Autoimmunity against p53 predicts invasive cancer with poor survival in patients with an ovarian mass.

Serum autoantibodies against the p53 protein (p53 AAb) were analysed with a newly developed enzyme-linked immunosorbent assay (ELISA) based on highly purified and renatured p53. In a hospital-based cohort study, preoperative sera from 113 patients with ovarian cancer, 15 patients with borderline tumours and 117 patients with benign tumours of the ovaries were studied. The prevalence of p53 AAb in patients with invasive cancer was 19% (21/113). No p53 AAb were found in patients with borderline lesions or benign tumours. The ELISA had a specificity for malignancy of 99% (1 of 117; false-positive from a patient with severe diabetes mellitus) and a likelihood ratio (LR+) for a positive test result of 21.7 (elevated CA125 and malignancy: LR+ 3.7). p53 AAb were only detectable in patients with immunohistochemical staining of nuclear p53 in the tumour (P = 0.006). Presence of p53 AAb positively correlated with tumour stage (P = 0.034) and grade (P = 0.009). Kaplan-Meier analysis showed both a shortened overall survival (P = 0.0016, log-rank) and relapse-free survival (P = 0.055) for p53 AAb-positive patients (median follow-up 22 months). High titres related to even worse prognosis. p53 AAb independently related to poor survival adjusting for stage (P = 0.026), grade (P = 0.029) and residual disease after surgery (P = 0.005). Preoperative findings of adnexal mass with serum p53 AAb are strongly suggestive of an aggressive invasive ovarian cancer.

Adolescent↗