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H Freitag

Publications and source records attributed to H Freitag.

At least 19 recordsLinked to original sources
PubMed2003

Language lateralization by Wada test and fMRI in 100 patients with epilepsy.

Comparing the determination of language dominance using fMRI with results of the Wada test in 100 patients with different localization-related epilepsies, the authors found 91% concordance between both tests. The overall rate of false categorization by fMRI was 9%, ranging from 3% in left-sided temporal lobe epilepsy (TLE) to 25% in left-sided extratemporal epilepsy. Language fMRI might reduce the necessity of the Wada test for language lateralization, especially in TLE.

Adult↗
PubMed2002

Epilepsy surgery outcome in children with focal epilepsy due to tuberous sclerosis complex.

Tuberous sclerosis complex (TSC) is frequently associated with focal epilepsy due to cerebral tubers. Seizures are the first symptoms in most patients with brain involvement. These epilepsies are frequently severe, drug-resistant and may have a negative impact on the child's global development. Although most epilepsies are multicentric, these patients may be candidates for epilepsy surgery, if it is possible to determine a leading epileptogenic tuber. Nine patients with TSC were examined with long-term video-EEG monitoring, different neuroimaging techniques and neuropsychological tests. A main epileptogenic tuber could be identified in all of our patients. We found good correlations between neuroimaging and EEG. Surgery was performed in eight patients. Seizure outcome was good in all. Two patients became seizure-free, one patient had a single prolonged seizure five days postoperatively, four patients had a significant seizure reduction of more than 75 % and one patient had a seizure reduction of more than 50 % after surgery without additional neurologic deficits. In conclusion, patients with TSC and drug-resistant epilepsy may benefit from epilepsy surgery with reduction in frequency and severity of seizures as well as improved mental and behavioural development leading to a better quality of life. In view of recent developments in functional and metabolic imaging, primary epileptogenic lesions will be more easily detectable in patients with diffuse brain involvement in TSC and surgical treatment may be more specifically applied at an earlier age to a selected subgroup of patients with this disorder.

Child↗
PubMed2001

Kranz anatomy is not essential for terrestrial C4 plant photosynthesis.

An important adaptation to CO2-limited photosynthesis in cyanobacteria, algae and some plants was development of CO2-concentrating mechanisms (CCM). Evolution of a CCM occurred many times in flowering plants, beginning at least 15-20 million years ago, in response to atmospheric CO2 reduction, climate change, geological trends, and evolutionary diversification of species. In plants, this is achieved through a biochemical inorganic carbon pump called C4 photosynthesis, discovered 35 years ago. C4 photosynthesis is advantageous when limitations on carbon acquisition are imposed by high temperature, drought and saline conditions. It has been thought that a specialized leaf anatomy, composed of two, distinctive photosynthetic cell types (Kranz anatomy), is required for C4 photosynthesis. We provide evidence that C4 photosynthesis can function within a single photosynthetic cell in terrestrial plants. Borszczowia aralocaspica (Chenopodiaceae) has the photosynthetic features of C4 plants, yet lacks Kranz anatomy. This species accomplishes C4 photosynthesis through spatial compartmentation of photosynthetic enzymes, and by separation of two types of chloroplasts and other organelles in distinct positions within the chlorenchyma cell cytoplasm.

Carbon Dioxide↗
PubMed2001

Procalcitonin as a diagnostic marker in patients with aspiration after closed head injury.

BACKGROUND: Aspiration of gastric content frequently induces early onset of pneumonia in patients with impaired consciousness after closed head injury and thus worsens the prognosis. Early detection of aspiration and appropriate therapy are essential. The purpose of the study was to assess the diagnostic value of procalcitonin (ProCT) in aspiration of gastric content and to evaluate its prognostic impact in patients with closed head injury. METHODS: Twenty-three patients with isolated closed head injury (Glasgow Coma Scale [GCS] score < or = 8) were studied. Bronchoscopy was done on admission; chest radiographs and routine laboratory examination including C-reactive protein were performed daily. ProCT was analyzed 12, 24, 36 and 72 hours after trauma using an immunoluminometric assay. RESULTS: ProCT was higher throughout the study period in 9 patients with persistent radiological signs suspect for aspiration of gastric content and there was evidence of aspiration of gastric content during bronchoscopy on admission. Median ProCT values of 1.397 ng/ml (range, 0.372 to 8.358 ng/ml) on admission increased to 2.144 ng/ml (range, 0.716 to 6.910 ng/ml) 24 hours after trauma, and then decreased to baseline values of 1.711 ng/ml (range, 0.611 to 6.639 ng/ml) as early as 36 hours after trauma. In patients without signs of aspiration of gastric content, ProCT values did not exceed 0.418 ng/ml. Non-survivors had higher serum levels of ProCT throughout the study period. CONCLUSION: Our findings suggest that ProCT is a useful diagnostic marker for detecting aspiration of gastric content while the prognostic value of ProCT for predicting survival after isolated closed head injury was moderate.

Adult↗
PubMed2001

A prospective randomized trial comparing the cuffed oropharyngeal airway (COPA) with the laryngeal mask for elective minor surgery in female patients.

OBJECTIVE: The cuffed oropharyngeal airway (COPA), a modified Guedel-type airway with a cuff at the distal end, has recently been introduced into anesthetic practice. The aim of this study was to compare the COPA with the well established laryngeal mask airway (LMA). Special consideration was granted to the difficult airway. PATIENTS AND METHODS: Two hundred and fifty-two women of ASA class I or II undergoing elective gynecological or breast surgery under general anesthesia were randomly assigned to either cuffed oropharyngeal or laryngeal mask airway management. Insertion and removal of the device, airway maintenance throughout the procedure, and postoperative course and complications were assessed. RESULTS: A patent airway was obtained with either device in all patients. Global first-time success rates for insertion were similar in the two study groups. Initial failure of correct placement occurred more frequently in the COPA as compared to the LMA group if the interincisor gap was < 5 cm and mandibular protrusion impossible (p < 0.01). Neither thyromental distance nor Mallampati scores nor body mass index (BMI) were of relevance for insertion success. The incidence of postoperative complaints and of mucosal injuries was significantly higher with the LMA. CONCLUSION: On the whole, high overall success and low complication rates render COPA and LMA equally suitable for routine anesthetic airway management.

Adult↗
PubMed2001

S(+)-ketamine for rectal premedication in children.

Our purpose for this prospective, randomized, and double-blinded study was to evaluate the anesthetic efficacy of S(+)-ketamine, an enantiomer of racemic ketamine, compared with a combination of S(+)-ketamine and midazolam, and plain midazolam for rectal premedication in pediatric anesthesia. Sixty-two children, ASA physical status I and II, scheduled for minor surgery, were randomly assigned to be given rectally one of the following: 1.5 mg/kg preservative-free S(+)-ketamine, a combination of 0.75 mg/kg preservative-free S(+)-ketamine and 0.75 mg/kg midazolam, or 0.75 mg/kg midazolam. Preoperative anesthetic efficacy was graded during a period of 20 min by using a five-point scale from 1 = awake to 5 = asleep. Tolerance during anesthesia induction via face mask was graded by using a four-point scale from 1 = very good to 4 = bad. A sufficient anesthetic level (> or = 3) after rectal premedication was reached in 86% in midazolam/S(+)-ketamine premedicated children, in 75% in midazolam premedicated children, but only in 30% in S(+)-ketamine premedicated children (P < 0.05 S(+)-ketamine versus midazolam/S(+)-ketamine and midazolam groups). The incidence of side effects after rectal premedication was rare. Whereas the mask acceptance score was comparable in the three study groups, a 25% rate of complications during anesthesia induction via face was observed in the S(+)-ketamine study group (P < 0.05 versus other study groups). Our conclusions are that S(+)-ketamine for rectal premedication in the dose we chose shows a poor anesthetic effect and a frequent incidence of side effects during induction of anesthesia via face mask compared with the combination of midazolam/S(+)-ketamine and plain midazolam. Dose-response studies of S(+)-ketamine for rectal premedication in pediatric anesthesia may be warranted.

Administration, Rectal↗
PubMed2001

Ondansetron is no more effective than supplemental intraoperative oxygen for prevention of postoperative nausea and vomiting.

UNLABELLED: Supplemental oxygen maintained during and for 2 h after colon resection halves the incidence of nausea and vomiting. Whether supplemental oxygen restricted to the intraoperative period is sufficient remains unknown. Similarly, the relative efficacy of supplemental oxygen and ondansetron is unknown. We tested the hypothesis that intraoperative supplemental oxygen reduces the incidence of postoperative nausea and vomiting. Patients (n = 240) undergoing gynecological laparoscopy were given a standardized isoflurane anesthetic. After induction, they were randomly assigned to the following three groups: routine oxygen administration with 30% oxygen, balance nitrogen (30% Oxygen group), supplemental oxygen administration with 80% oxygen, balance nitrogen (80% Oxygen group), and Ondansetron 8 mg (immediately after induction), combined with 30% oxygen, balance nitrogen (Ondansetron group). The overall incidence of nausea and/or vomiting during the initial 24 postoperative h was 44% in the patients assigned to 30% oxygen and 30% in the Ondansetron group, but only 22% in those given 80% oxygen. The incidence was thus halved by supplemental oxygen and was significantly less than with 30% oxygen. There were, however, no significant differences between the 30% oxygen and ondansetron groups, or between the ondansetron and 80% oxygen groups. We conclude that supplemental oxygen effectively prevents postoperative nausea and vomiting after gynecological laparoscopic surgery; furthermore, ondansetron is no more effective than supplemental oxygen. IMPLICATIONS: Supplemental oxygen reduces the risk of postoperative nausea and vomiting (PONV) as well or better than 8 mg of ondansetron. Because oxygen is inexpensive and essentially risk-free, supplemental oxygen is a preferable method of reducing PONV.

Adult↗
PubMed2001

New observations on the secondary chemistry of world Ephedra (Ephedraceae).

For several millennia, stem extracts of Ephedra (Ephedraceae, Gnetales) have been used as folk medicines in both the Old and New World. Some species were used in treatments of questionable efficacy for venereal disease in North America during the last century. Many Eurasian species produce phenylethylamine alkaloids, mostly ephedrine and pseudoephedrine, that interact with adrenergic receptors in the mammalian sympathetic nervous system. Asian Ephedra have been used recently in the clandestine manufacture of a street drug, methamphetamine. Although ephedrine alkaloids are not detectable in New World species of Ephedra, together with Asian species they contain other nitrogen-containing secondary metabolites with known neuropharmacological activity. Many mesic and particularly xeric species worldwide accumulate substantial amounts of quinoline-2-carboxylic acids, or kynurenates, in their aerial parts. Many species of Ephedra accumulate cyclopropyl amino acid analogues of glutamate and proline in their stems and roots, and particularly in the seed endosperm. Mesic species synthesize substantial amounts of three L-2-(carboxycyclopropyl)glycine stereomers rarely seen in nature. A cyclopropyl analogue of proline with known antimicrobial activity, cis-3,4-methanoproline, is found in large amounts in the stems and seeds of many Ephedra species. The ability to synthesize cyclopropyl amino acids may be an ancestral feature in the taxon. The natural function in the taxon of these three groups of secondary compounds remains to be established.

Journal Article↗
PubMed2000

Electrical stimulation of the vestibular system prevents postoperative nausea and vomiting.

BACKGROUND: Electrical stimulation of the vestibular system may prevent nausea and vomiting. We studied the influence of transcutaneous impulse stimulation in prevention of postoperative nausea and vomiting (PONV) following gynaecological surgery. METHODS: In this randomised study 70 women undergoing elective gynaecological surgery under general anaesthesia were assigned to receive either the activated (stimulation group) or the inactivated (non-stimulation group) impulse stimulator. The stimulator comprises the stimulator itself, two negative electrodes on a headset applied over both mastoid processes and a nuchal positive electrode. The device yielded a pulse frequency of 5 Hz direct current, individually adjustable between 0.5 and 4 mA. A trapezoid stimulation of 50 ms was applied. Nausea, vomiting, dizziness and the amount of antiemetic drugs used were assessed during the first 4 h postoperatively. RESULTS: Lower postoperative nausea scores with a lower incidence of vomiting and postoperative dizziness were found in the stimulation group. A lower amount of antiemetic drugs was needed in the stimulation group when compared to the non-stimulation group (P<0.01 between groups). CONCLUSION: This study suggests that electrical stimulation of the vestibular system may be useful in prevention of PONV.

Adult↗
PubMed1999

Single-injection paravertebral block compared to general anaesthesia in breast surgery.

BACKGROUND: Breast surgery is frequently associated with post-operative nausea, vomiting, pain and painful restricted movement. Paravertebral block may be an alternative to general anaesthesia for this type of surgery. We studied the single-injection paravertebral block at the level of T4 and report a comparison of single-injection paravertebral block to general anaesthesia for breast surgery. METHODS: After written informed consent was obtained, 86 patients were enrolled in this prospective study. Forty-four women were randomly allocated to receive a single-injection paravertebral block at the level of T4, while 42 women received general anaesthesia. The surgical procedures varied from lumpectomy (wide local excision of a tumour) to modified radical mastectomy with axillary dissection. The block was performed according to the guidelines described by Eason and Wyatt using 0.3 ml x kg(-1) (maximum dose 150 mg) of bupivacaine 0.5%. The skin and the underlying tissues were infiltrated with local anaesthetic solution two fingers (about 3 cm) from the anatomical midline and level with the cephalad end of the vertebral spine. RESULTS: Time for performance of blocks lasted from 4 to 9 min. Recovery from anaesthesia or sedation was shortened, while postoperative pain scores (VAS), the incidence of vomiting and the requirement for analgesics were lower in the paravertebral group. Less painful restricted movement was observed in the paravertebral block group. Paravertebral block was inadequate in 6.8% of patients. Epidural spread with paraparaesis and Horner triad was assumed in one patient. CONCLUSION: Single-injection paravertebral block at the level of T4 represents a suitable alternative to general anaesthesia in women undergoing breast surgery.

Adult↗
PubMed1996

Carbohydrate-deficient transferrin as a screening marker for drinking in a general hospital population.

We investigated the usefulness of the laboratory marker of alcohol consumption carbohydrate-deficient transferrin (CDT) in 101 consecutively admitted patients in a surgical and internal medical ward of a hospital in a rural wine-growing area. Four major aspects were considered: the influence of liver disease, the method of expression of CDT values (relative % vs absolute units/1), level and pattern of alcohol consumption and comparison with y-glutamyl transferase (GGT). The results show that %CDT is a more valuable discriminating marker of high alcohol consumption than absolute CDT values and its usefulness in this respect is independent of changes in serum total transferrin levels, as in liver disease. Sensitivity and specificity of % CDT were 70 and 98% respectively, compared with 65 and 83% respectively for GGT.

Adult↗
PubMed1995

Development and characterization of a rapid assay for bedside determinations of cardiac troponin T.

BACKGROUND: The appearance of cardiac proteins in blood is the most specific and sensitive indicator of acute myocardial cell necrosis. The measurement of cardiac markers, however, is time consuming and requires sophisticated equipment. To facilitate the biochemical detection for acute myocardial cell necrosis, a whole-blood rapid assay device for cardiac troponin T detection was developed that provides a test result within 20 minutes. METHODS AND RESULTS: Monoclonal antibody M7 is labeled with gold particles, and antibody 1B10 is labeled with biotin. Both antibodies, as well as buffer substances and detergents, are adsorbed onto paper fleeces mounted below an application well. Heparinized blood (160 microL) applied to this well solubilizes the dry chemistry reagents. Blood cells are separated from plasma via a glass-fiber fleece. The immunocomplexes formed are concentrated within the reading zone by binding of the biotin-labeled antibody with streptavidine immobilized to the test device. Troponin T bound to the test device serves as a control. The detection limit of this assay is 0.18 microgram/L with a cross-reactivity with skeletal troponin T of 0.5%. In clinical analyses involving 25 healthy volunteers, 62 patients with chest pain but without myocardial ischemia, 35 patients with acute myocardial infarction, 24 patients with minor myocardial cell damage due to radiofrequency ablation, and 35 patients with unstable angina, the rapid assay was comparable to the troponin T enzyme immunoassay in regard to sensitivity and specificity. CONCLUSIONS: This newly developed assay allows accurate, rapid, and convenient diagnosis of acute myocardial cell necrosis.

Angina, Unstable↗
PubMed1990

[Poly-, multiple trauma and intra-abdominal injuries].

The present work deals with the problem of abdominal injuries in polytraumatized patients. The results were obtained from a retrospective study of the records of 530 polytraumatized patients treated at the Central Hospital of the German Federal Armed Forces (Bundeswehr). In all, 193 of these patients had abdominal injuries. The overall mortality was 23.8% (n = 126): mortality among the patients with abdominal injuries was 26% (n = 50). Abdominal injuries alone led to death in 9.1% (n = 1), but mortality increased to 18.4% when at least one extra-abdominal injuries was also present. A combination of abdominal injuries and two or more extra-abdominal lesion led to a mortality rate of 27%. Mortality was found to be age- and sex-related: in young children and patients over 55 years (especially those around 70) mortality was 33.3%-72%. Among the cases with fatal outcome there was a female-to-male ratio of 3:2. The most common causes of death were: hemorrhage shock (62.3%), head injuries (37.7%), septicemia (8.1%), pneumonia, and ARDS (5.4% each). Within the last eight years we have used the following supplementary examination methods: computed tomography, peritoneal lavage, and ultrasonography. The retrospective study has shown that CT is not the examination of choice. The reliability with lavage and ultrasonography was approximately the same, but lavage was found to be more dangerous. Therefore, we abandoned lavage and used sonography only. However, we are of the opinion that any surgeon should use the examination method that has yielded the best results for him or her, to ensure the best possible outcome for the patient.

Abdominal Injuries↗
PubMed1985

A water-soluble form of porin from the mitochondrial outer membrane of Neurospora crassa. Properties and relationship to the biosynthetic precursor form.

Mitochondrial porin, the outer membrane pore-forming protein, was isolated in the presence of detergents and converted into a water-soluble form. This water-soluble porin existed under nondenaturing conditions as a mixture of dimers and oligomers. The proportion of dimers increased with decreasing porin concentration during conversion. Water-soluble porin inserted spontaneously into artificial bilayers as did detergent-solubilized porin. Whereas the latter form had no specific requirements for the lipid composition of the bilayer, water-soluble porin inserted only into membranes containing a sterol, and only in the presence of very low concentrations of Triton X-100 (0.001% w/v) in the solution bathing the bilayer. The channels formed by water-soluble porin were indistinguishable from those formed by detergent-purified porin with respect to specific conductance and voltage dependence of conductance. Water-soluble porin bound tightly in a saturable fashion to isolated mitochondria. The bound form was readily accessible to added protease, indicating its presence on the mitochondrial surface. The number of binding sites was in the range of 5-10 pmol/mg of mitochondrial protein. Water-soluble porin apparently binds to a site on the assembly pathway of the porin precursor, since mitochondria whose binding sites were saturated with the water-soluble form did not import porin precursor synthesized in a cell-free system.

Bacterial Outer Membrane Proteins↗
PubMed1982

Purification and characterisation of a pore protein of the outer mitochondrial membrane from Neurospora crassa.

The major protein of the outer mitochondrial membrane of Neurospora was purified. On dodecylsulfate-containing gels it displayed a single band with an apparent molecular weight of 31 000. Reconstitution experiments with artificial lipid bilayers showed that this protein forms pores. Pore conductance was dependent on the voltage across the membrane. The protein inserted into the membrane in an oriented fashion, the membrane current being dependent on the sign of the voltage. Single pore conductance was 5nS, suggesting a diameter of 2 nm of the open pore. This mitochondrial protein shows a number of similarities to the outer membrane porins of gram-negative bacteria.

Chemical Phenomena↗
PubMed1982

Biosynthesis of mitochondrial porin and insertion into the outer mitochondrial membrane of Neurospora crassa.

Mitochondrial porin, the major protein of the outer mitochondrial membrane is synthesized by free cytoplasmic polysomes. The apparent molecular weight of the porin synthesized in homologous or heterologous cell-free systems is the same as that of the mature porin. Transfer in vitro of mitochondrial porin from the cytosolic fraction into the outer membrane of mitochondria could be demonstrated. Before membrane insertion, mitochondrial porin is highly sensitive to added proteinase; afterwards it is strongly protected. Binding of the precursor form to mitochondria occurs at 4 degrees C and appears to precede insertion into the membrane. Unlike transfer of many precursor proteins into or across the inner mitochondrial membrane, assembly of the porin is not dependent on an electrical potential across the inner membrane.

Chemical Phenomena↗