Biomedical subjects
Publications and source records attributed to J Schmidt.
IMPLICATIONS: We present a technique of intraoperative monitoring of the recurrent laryngeal nerve using a surface electrode attached to a routine endotracheal tube. The technique proved noninvasive, easy to use, and reliable in 151 prospective consecutive patients for preventing permanent laryngeal nerve damage in thyroid surgery.
IMPLICATIONS: We present a case of systemic arterial embolism during wedge resection of the lung. The importance of transesophageal echocardiographic monitoring is described.
Crude aqueous extracts from Arabidopsis leaves were subjected to chromatographic separations, after which the different fractions were monitored for antimicrobial activity using the fungus Neurospora crassa as a test organism. Two major fractions were obtained that appeared to have the same abundance in leaves from untreated plants versus leaves from plants challenge inoculated with the fungus Alternaria brassicicola. One of both major antimicrobial fractions was purified to homogeneity and identified by 1H nuclear magnetic resonance, gas chromatography/electron impact mass spectrometry, and gas chromatography/chemical ionization mass spectrometry as 4-methylsulphinylbutyl isothiocyanate (ITC). This compound has previously been described as a product of myrosinase-mediated breakdown of glucoraphanin, the predominant glucosinolate in Arabidopsis leaves. 4-Methylsulphinylbutyl ITC was found to be inhibitory to a wide range of fungi and bacteria, producing 50% growth inhibition in vitro at concentrations of 28 microM for the most sensitive organism tested (Pseudomonas syringae). A previously identified glucosinolate biosynthesis mutant, gsm1-1, was found to be largely deficient in either of the two major antimicrobial compounds, including 4-methylsulphinylbutyl ITC. The resistance of gsm1-1 was compared with that of wild-type plants after challenge with the fungi A. brassicicola, Plectosphaerella cucumerina, Botrytis cinerea, Fusarium oxysporum, or Peronospora parasitica, or the bacteria Erwinia carotovora or P. syringae. Of the tested pathogens, only F. oxysporum was found to be significantly more aggressive on gsm1-1 than on wild-type plants. Taken together, our data suggest that glucosinolate-derived antimicrobial ITCs can play a role in the protection of Arabidopsis against particular pathogens.
Infection of cells by herpesviruses is initiated by the interaction of viral envelope glycoproteins with cellular receptors. In the alphaherpesvirus pseudorabies virus (PrV), the causative agent of Aujeszky's disease in pigs, the essential glycoprotein D (gD) mediates secondary attachment of virions to target cells by binding to newly identified cellular receptors (R. J. Geraghty, C. Krummenacher, G. H. Cohen, R. J. Eisenberg, and P. G. Spear, Science 280:1618-1620, 1998). However, in the presence of compensatory mutations, infection can also occur in the absence of gD, as evidenced by the isolation in cell culture of an infectious gD-negative PrV mutant (PrV-gD(-) Pass) (J. Schmidt, B. G. Klupp, A. Karger, and T. C. Mettenleiter, J. Virol. 71:17-24, 1997). PrV-gD(-) Pass is replication competent with an only moderate reduction in specific infectivity but appears to bind to receptors different from those recognized by wild-type PrV (A. Karger, J. Schmidt, and T. C. Mettenleiter, J. Virol. 72:7341-7348, 1998). To analyze whether this alteration in receptor usage in vitro influences infection in vivo, the model host mouse and the natural host pig were intranasally infected with PrV-gD(-) Pass and were compared to animals infected by wild-type PrV. For mice, a comparable progress of disease was observed, and all animals infected with mutant virus died, although they exhibited a slight delay in the onset of symptoms and, correspondingly, a longer time to death. In contrast, whereas wild-type PrV-infected pigs showed clinical signs and histological and histopathological findings typical of PrV infection, no signs of disease were observed after infection with PrV-gD(-) Pass. Moreover, in these animals, virus-infected cells were not detectable by immunohistochemical staining of different organ samples and no virus could be isolated from nasal swabs. Mutations in glycoproteins B and H were found to correlate with, and probably contribute to, gD-independent infectivity. In conclusion, although PrV-gD(-) Pass is virulent in mice, it is apparently unable to infect the natural host, the pig. This altered host range in vivo correlates with a difference of receptor usage in vitro and demonstrates for the first time the importance of gD receptors in alphaherpesvirus infection of an animal host.
During walking, the six legs of a stick insect can be coordinated in different temporal sequences or gaits. Leg coordination in each gait is controlled and stabilized by coordinating mechanisms that affect the action of the segmental neuronal networks for walking pattern generation. At present, the motor program for single walking legs in the absence of movement-related coordinating intersegmental influences from the other legs is not known. This knowledge is a prerequisite for the investigation of the segmental neuronal mechanisms that control the movements of a leg and to study the effects of intersegmental coordinating input. A stick insect single middle leg walking preparation has been established that is able to actively perform walking movements on a treadband. The walking pattern showed a clear division into stance and swing phases and, in the absence of ground contact, the leg performed searching movements. We describe the activity patterns of the leg muscles and motoneurons supplying the coxa-trochanteral joint, the femur-tibial joint, and the tarsal leg joints of the middle leg during both walking and searching movements. Furthermore we describe the temporal coordination between them. During walking movements, the coupling between the leg joints was phase-constant; in contrast during searching movements, the coupling between the leg joints was dependent on cycle period. The motor pattern of the single leg generated during walking exhibits similarities with the motor pattern generated during a tripod gait in an intact animal. The generation of walking movements also drives the activity of thoraco-coxal motoneurons of the deafferented and de-efferented thoraco-coxal leg joint in a phase-locked manner, with protractor motoneurons being active during swing and retractor motoneurons being active during stance. These results show that for the single middle leg, a basic walking motor pattern is generated sharing similarities with the tripod gait and that the influence of the motor pattern generated in the distal leg joints is sufficient for driving the activity of coxal motoneurons so an overall motor pattern resembling forward walking is generated.
In the stick insect, Cuniculina impigra, intracellular recordings from mesothoracic motoneurons that control flexion and extension of the tibia and depression and levation of the trochantero-femur were made while the leg performed walking-like movements on a treadband or stereotyped rhythmic searching movements. We were interested in how synaptic input and intrinsic properties contribute to form the activity pattern of motoneurons during rhythmic leg movements without sensory feedback from other legs. During searching and walking, motoneurons expressed a rhythmic bursting pattern that was formed by a depolarizing input followed by a hyperpolarizing input in the inter-burst interval. This basic pattern was similar in all fast, semi-fast, and slow motoneurons that were recorded. Hyperpolarizations were in synchrony with activity in the antagonistic motoneurons. De- and hyperpolarizations were associated with a decrease in input resistance. All motoneurons showed spike frequency adaptation when depolarized by current injection to a membrane potential similar to that observed during walking. In the hyperpolarizing phase of fast flexor motoneurons, the initial maximum hyperpolarization was followed by a sag in potential toward more depolarized values. Consistent with this observation, only fast flexor motoneurons developed a depolarizing sag potential when hyperpolarized by injection of constant negative current.
Intussusception of the appendix vermiformis in adults is an unusual entity. We present a 52-year-old male patient with intussusception of the appendix due to a mucinous cystadenoma, and discuss the clinical features, preoperative diagnosis, classification and therapy of this condition together with a review of the literature.
In patients with severe pulmonary disease, laparoscopic techniques are not advised. The authors report their preliminary experience with laparoscopic intraperitoneal onlay polytetrafluoroethylene mesh repair for inguinal hernia during spinal anesthesia in patients with chronic obstructive pulmonary disease. Spinal anesthesia was performed using hyperbaric bupivacaine (3-3.5 mL) injected at L2-L3. If necessary, additive opioid therapy was administered. Under low-pressure pneumoperitoneum (10 mm Hg), polytetrafluoroethylene mesh was stapled securely on the posterior inguinal wall to spare epigastric and iliac vessels. Fifteen patients underwent surgery. Median age was 62 years. All patients were classified American Society of Anesthesiologists physical status III/IV. Mean forced expiratory volume in the first second was 1.1 L/s. Median operating time was 20 minutes. Postoperative recovery was uneventful for all patients. The average duration of hospital stay was 1.5 days. Seroma or hematoma was not noted. Six-month follow-up did not show recurrence or infection. This technique is an effective method of repair of inguinal hernia in patients with severe chronic obstructive pulmonary disease, and it provides a maximum of comfort.
OBJECTIVE: The aim of this observational study was to assess the influence of a new combiphasic oral contraceptive on cycle control, tolerability and acne in a large cohort of women who wanted to switch from their previous oral contraceptive. METHODS: A total of 2,280 women were enrolled in this clinical evaluation at 232 centers in Germany. All women switched from their previous pill to a combiphasic oral contraceptive containing ethinylestradiol and desogestrel (combiphasic EE/DSG; comprising 25 microg desogestrel and 40 microg ethinylestradiol for 7 days followed by 125 microg desogestrel and 30 microg ethinylestradiol for 15 days and then a 6-day pill-free interval) for three cycles. RESULTS: Most women (53%) had previously used a monophasic oral contraceptive containing 20 or 30-35 microg ethinylestradiol. The most frequent reasons for switching were bleeding irregularities (41% of women), other menstrual disorders (27%) and migraine/headache (10%). After switching to combiphasic EE/DSG, cycle control improved significantly: the incidences of spotting and breakthrough bleeding decreased from 33% and 23% of women, respectively, before the start of the study, to 7% and 3% of women at the end of the study period. At the end of the study, acne was no longer present in 37% of the 592 women who had acne at the start of the study, and subjective complaints such as headaches were less frequent than before. Most women were satisfied or very satisfied with the combiphasic oral contraceptive and 89% wished to continue using it. CONCLUSIONS: The results of this observational clinical evaluation indicate that in everyday use, for women who wish to switch from another oral contraceptive, combiphasic EE/DSG is an effective and well-tolerated oral contraceptive, which improves cycle control and has a beneficial effect on acne.
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Surgical treatment in cases where disturbances of the nasal patency causes changes in the nasal inferior turbinates is controversial. The authors performed light- and electron microscopy and morphometric examinations of the mucous membrane of the nasal inferior turbinates obtained after partial inferior turbinectomy in patients with vasomotor and perennial allergic rhinitis and compensation hypertrophy of the nasal inferior turbinate accompanied by nasal deviation of the septum. In specimens obtained from patients with vasomotor rhinitis, a small number of glands and fibrosis of the lamina propria was observed. In specimens obtained from perennial allergic rhinitis patients, plenty of glands and large oedema was observed. In the group with compensatory hypertrophy of the inferior turbinate, normal glands and fibred areas around the vessels were observed. The largest histopathological changes of degeneration and hypertrophy of the nasal mucosa were observed in vasomotor rhinitis patients. Histopathological examination of nasal mucosa slides confirmed the usefulness of a partial inferior turbinectomy, but only in vasomotor rhinitis patients.
In vitro studies with the transprosthetic drainage system (TDS) have revealed a reduction in intrafemoral pressure in cemented total hip prosthesis. The aim of the present study was to establish whether the incidence of fat embolic syndrome (FES) is also reduced. Ten patients underwent standardized cemented total hip replacement using TDS under standardized general anaesthesia. The usual peri-operative monitoring measures were extended to include cardiopulmonary monitoring (pulmonary artery catheter, intra-arterial blood pressure) and two-dimensional transoesophageal echocardiography. Previous studies had reported an increased risk for fat embolic syndrome with conventional, and even with vacuum cementing techniques. Our recorded cardiopulmonary data and the data provided by two-dimensional transoesophageal echocardiography show a significant reduction in pulmonary embolism with TDS. This technique can be recommended in particular for high-risk patients (osteoporosis, elderly patients) and the implantation of long femoral stems. On the basis of the clinical data, a new femoral stem allowing the use of the TDS technique is being developed.
Surgical treatment in cases of disturbances of nasal patency caused changes in the nasal inferior turbinates are controversial. The authors performed the microscopic (light microscope) and morphometric examinations of mucous membrane of the nasal inferior turbinates obtained after inferior turbinoplasty in patients with vasomotor and perennial allergic rhinitis and compensation hypertrophy of nasal inferior turbinate accompanied of nasal deviation septum. Analysing of morphologic changes in mucous membrane of the nasal inferior turbinates verified of clinic indications to inferior turbinoplasty.
The aim of our study was evaluation of the results of clinical examination in patients with vasomotor and perennial allergic rhinitis and assessment of number of blood vessels, nerve fibres and mast cells on the basis of immunohistoenzymatic examination. There were 42 patients examined aged from 18 to 50 and divided into three groups: I--16 patients with vasomotor rhinitis and II--14 patients with perennial allergic rhinitis and III--12 patients (control) with nasal septum deviation. On the basis of the patient's history data, clinical otorhinolaryngologic examination and active anterior rhinomanometry the patients were qualified to bilateral inferior turbinectomy. The nasal mucosa removed during surgery underwent immunohistoenzymatic examination using the monoclonal antibody against the tryptase of mast cells (MCT company, DAKO), the endothelin of blood vessels (EC - DAKO) and the neurospecific enolase (NSE - DAKO). In examined groups of patients with vasomotor and perennial allergic rhinitis and control group similar escalation of clinical symptoms expressed by means of points index were stated. In immunohistoenzymatic studies the differences in mean number of blood vessels and nerve fibres between examined groups were not statistically significant, however statistically significant difference concerned higher number of mast cells patients with vasomotor rhinitis in comparison to perennial allergic rhinitis.
The myogenic determination factors (MDFs) are transcriptional activators that target E boxes in many muscle-specific promoters, including those of the genes coding for the subunits of the acetylcholine receptor. It is not known, however, if in vivo a given E box in a transcriptionally active gene is occupied, either uniquely by one MDF or randomly by all MDFs. We have analyzed expression of MDF and acetylcholine receptor subunits in cultured mouse muscle cells and, using chromatin immunoprecipitation, have determined which individual MDFs reside at promoters of several receptor subunit genes. We find that before fusion, C2C12 cells express myf-5, MyoD, and myogenin, all of which take up residence at promoters of all subunits except epsilon. At this stage, herculin is present in limited amounts and is detected mainly at the gamma and delta subunit genes. On myotube formation, herculin reaches high levels; concomitantly, the epsilon subunit gene becomes a common MDF target and begins to be expressed. In general, any MDF protein that is expressed also is present on transcriptionally active receptor genes; transcriptional activity of target genes correlates with occupancy by MDF, in particular, herculin.
The present study examined the effects of intrathecal (i.t.) administration of 5-hydroxytryptamine (5-HT; 0.1-100 microg) on mechanical hyperalgesia associated with neuropathic pain (chronic constriction of the sciatic nerve model and diabetic model) and inflammatory pain (carrageenan and polyarthritic models) in rats. Results demonstrated that the hyperalgesia observed in the mononeuropathic and diabetic rats was attenuated by 5-HT; the active dose, however, was 100- to 1000-fold higher than that required in normal rats, and was moderately effective. In the two experimental models of inflammatory pain, 5-HT was not markedly or similarly active. In the carrageenan model, 5-HT at the highest dose was only weakly effective whereas in the polyarthritic model it was inactive. Together, these results show that 5-HT has antinociceptive effects in several rat pain models, except in the model of diffuse pain (polyarthritic rats). Its antinociceptive effects in these models, however, are slight and differ from those observed in normal rats.
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In flowering plants, the developing embryo consists of growing populations of cells whose fates are determined in a position-dependent manner to form the adult organism. Mutations in the FACKEL (FK) gene affect body organization of the Arabidopsis seedling. We report that FK is required for cell division and expansion and is involved in proper organization of the embryo. We isolated FK by positional cloning. Expression analysis in embryos revealed that FK mRNA becomes localized to meristematic zones. FK encodes a predicted integral membrane protein related to the vertebrate lamin B receptor and sterol reductases across species, including yeast sterol C-14 reductase ERG24. We provide functional evidence that FK encodes a sterol C-14 reductase by complementation of erg24. GC/MS analysis confirmed that fk mutations lead to accumulation of intermediates in the biosynthetic pathway preceding the C-14 reductase step. Although fk represents a sterol biosynthetic mutant, the phenotype was not rescued by feeding with brassinosteroids (BRs), the only plant sterol signaling molecules known so far. We propose that synthesis of sterol signals in addition to BRs is important in mediating regulated cell growth and organization during embryonic development. Our results indicate a novel role for sterols in the embryogenesis of plants.