PubMed Health⌕ Search

Biomedical subjects

A Rohr

Publications and source records attributed to A Rohr.

At least 19 recordsLinked to original sources
PubMed2006

Selective affection of hippocampal CA-1 neurons in patients with transient global amnesia without long-term sequelae.

The aetiology, pathomechanisms and anatomical correlates of transient global amnesia (TGA) still remain obscure. Recently, focal MR-signal diffusion-weighted imaging (DWI) changes in the hippocampus have been described in patients with TGA, but the exact localization, long term outcome and pathophysiological nature of these lesions still remain unknown. The topography and time course of hippocampal DWI lesions in 41 TGA patients was studied using serial 3 T high-resolution MR-imaging and correlated to clinical and neuropsychometric results. Of these, 29 patients showed 36 DWI lesions with corresponding T(2) lesions in the hippocampus within a time window of 48 h after onset. Almost all lesions (94%; 34/36) were selectively found in the CA-1 sector (Sommer sector) of the hippocampal cornu ammonis. Most DWI lesions (8/10) were already detectable in the peri-acute phase <6 h after onset of symptoms. A follow-up study 4-6 months after the episode did not show evidence for residual structural sequelae of these lesions (n = 20/20). A venous MR angiography of the intracranial dural sinus showed an asymmetric venous drainage in 21/24 (88%) patients. In 11/16 (69%) patients with unilateral lesions, the asymmetry corresponded to the side of the DWI lesion. Significant episodic verbal memory deficits in the acute phase (n = 14/18) were associated with lesions of the dominant hemisphere while impairment of visuospatial memory was associated with lesions of the non-dominant hemisphere. Persistent neuropsychological sequelae were not detected 4-6 months after the episode (n = 16). This is the first prospective study combining high-resolution imaging and neuropsychometry analysing the detailed functional anatomy and outcome of hippocampal DWI/T(2) lesions in TGA supporting the view the TGA being a benign transient disorder. The TGA can be considered a model for a focal transient perturbation of memory circuits in the temporo-mesial region.

Adult↗
PubMed2002

[Radiological assessment of small bowel obstructions: Value of conventional enteroclysis and dynamic MR-enteroclysis].

PURPOSE: To compare small bowel lesions, especially stenoses, with conventional enteroclysis, static MRI and dynamic MR-enteroclysis. MATERIALS AND METHODS: Forty-two patients with Crohn's disease or other suspected small bowel lesions were examined. MRI was performed in a static and a dynamic way either within one hour after conventional enteroclysis (n = 30) or a few days afterwards (n = 12). In order to monitor bowel filling and to characterize stenoses in a dynamic fashion, 4 series of coronal T2w HASTE breath hold sequences were used, first without additional bowel opacification and then during administration of 1,5 l methyl cellulose via a naso-intestinal tube in the MR unit. Intravenously applied Buscopan was used to reduce bowel movement. RESULTS: In 4 out of 42 Patients, application of methylcellulose was limited to 1000 ml because of gastrointestinal complaints or visible gastral reflux. All patients could be evaluated. Static MRI performed within one hour after conventional enteroclysis and no additional bowel opacification showed insufficient bowel distension. Distension was still better than in MRI without prior application of contrast medium. On the contrary, dynamic MR - enteroclysis lead to controlled and complete bowel distension which allowed for significantly better evaluation of normal bowel anatomy and pathological alterations of the gut. Because of a better bowel distension and dynamic evaluation, MR-enteroclysis revealed significantly more stenoses (n = 42) than MRI obtained with less distension (n = 27, p < 0.001), and characterization of lesions was comparable to conventional enteroclysis (p < 0.001). Fixed and non-fixed stenoses could be differentiated by dynamic MR-enteroclysis. Furthermore, extraluminal complication of Crohn's disease such as abscesses and fistulae or large bowel manifestation of disease were shown in 13 patients. CONCLUSIONS: Dynamic MR-enteroclysis is feasible in routine diagnostic work-up of the small bowel. It is superior in depicting intra- and extraluminal manifestation of small bowel lesions and enables characterization of stenoses comparable to conventional enteroclysis.

Adolescent↗
PubMed2001

Yersinia enterocolitica infection with multiple liver abscesses uncovering a primary hemochromatosis.

A 60-year-old man, although treated with antibiotics, suffered from a severe pyrexial illness of unknown origin, weight loss and intermittent abdominal pain. There was no history of diarrhea or common infections. Computed tomography and ultrasound imaging showed uncharacteristic multiple small lesions of the entire liver parenchyma. These lesions were histologically pyogenic abscesses. In addition, an unexpected, pronounced accumulation of iron pigment in hepatocytes and second degree fibrotic changes of the liver were detected. Serum iron and serum transferrin were low, but serum ferritin concentration and transferrin saturation were increased to the maximum. The demonstration of the cysteine-282-tyrosine mutation confirmed underlying primary hemochromatosis. Bacteriological cultures of the abscess material yielded Yersinia enterocolitica serotype O:3, while stool and blood cultures were negative. Antibiotic therapy with piperacillin/tazobactam and tobramycin was successful within a few days. A repeat CT scan and ultrasound imaging demonstrated complete regression of the pathologic liver morphology. The patient was discharged and treated with an orally administered fluoroquinolone for an additional 6 months. After this time the patient had no morphological residues of the infection except one enlarged lymph node near the portal vein but still was so weak that he was unable to work again. In conclusion, severe septic forms of yersiniosis are mainly found in patients with iron overload, due to a handicapped iron metabolism of the Yersinia bacteria. Mortality is high despite treatment.

Hemochromatosis↗
PubMed2000

Lack of anticipatory gaze-orienting responses in patients with right brain damage.

OBJECTIVE: To study eye movements during cervical proprioceptive stimulation by passive body rotation in darkness, with the head held stationary, in patients with right brain damage and hemineglect. BACKGROUND: At very low frequency, this stimulation is reported to produce an illusion of head turning in space and eye deviations directed opposite to trunk rotation (in the direction of the illusory head rotation). METHODS: Ten normal subjects and seven patients with unilateral cerebral lesions (five right brain-damaged patients with mild to moderate visuospatial neglect, two left brain-damaged patients without neglect) were included in the study. Subjects were seated on a rotating chair. Stimuli consisted of slow sinusoidal passive trunk rotations (+/-30 degrees, 0.01 Hz) while the head was fixed in space. RESULTS: Eye movements directed opposite to trunk rotation were typical for normal subjects and for left brain-damaged patients. In contrast, all right brain-damaged patients showed either eye movements in the direction of trunk rotation or no eye deviations at all. CONCLUSION: This result could characterize a lack of anticipatory coordinating gaze behavior in patients with right brain damage.

Aged↗
PubMed2000

Structurally diverse forms of HLA-B27 molecules are displayed in vivo in a cell type-dependent manner.

The formation of a trimeric complex, composed of heavy chain (HC), beta(2)-microglobulin (beta(2)m) and antigenic peptide, is generally believed to be a prerequisite for the expression of HLA class I molecules at the cell surface in vivo. Therefore, a possible role in immunological processes for HC/beta(2)m complexes devoid of peptide has not been seriously considered. Using a novel HLA-B*2705-transgenic rat model and monoclonal antibodies that distinguish between structurally different forms of HLA-B27 molecules, we demonstrate here that class I molecules which appear to lack antigenic peptides are expressed in abundance on a variety of cell types in lymphoid organs. These results imply a role for structurally diverse, possibly empty, MHC molecules in physiological T cell selection which has so far not been sufficiently appreciated.

Amino Acid Sequence↗
PubMed2000

Absorption of lefradafiban from different sites of the gastrointestinal tract.

AIMS: Fibrinogen receptor antagonists show a close relationship between plasma concentrations and inhibitory effect. Optimal efficacy at an acceptable bleeding risk requires low inter- and intrasubject variability on low peak trough fluctuation in receptor occupancy and therefore also of plasma concentrations. Therefore, the enteral absorption of lefradafiban, an orally available fibrinogen receptor antagonist prodrug, was investigated after local administrations to different sites of the gastrointestinal tract in order to investigate the feasibility of an oral extended release formulation. METHODS: Twelve healthy male subjects received in a randomised, open-labelled, four-period crossover trial four consecutive administrations of lefradafiban: 1. orally; 2. administration into the jejunum, 3. administration into the lower jejunum/ileum (300 cm distally to the teeth), and 4. administration into the lumen of the sigmoid region (30 cm proximally to the anus). Local intestinal administrations were performed through a gastrointestinal tube. RESULTS: Compared with oral administration, ratios [mean (two-sided 90% confidence intervals)] of maximum drug plasma concentrations and AUC(0,24 h) of fradafiban were 1.05 (0.80, 1.39) and 1.06 (0.85,1.31) after jejunal, 0.98 (0.75,1.30) and 0.98 (0.79,1.21) after ileal, 0.52 (0.39,0.69) and 0.68 (0.55,0.85) after colonic administration. Urinary excretion of fradafiban was about 16% of the dose after oral, jejunal and ileal applications whereas after rectal administration about 11% were excreted. CONCLUSIONS: Lefradafiban is absorbed throughout the entire gastrointestinal tract. Therefore, an extended release formulation seems to be feasible with regard to bioavailability.

Administration, Oral↗
PubMed1998

Involvement of two novel chaperones in the assembly of mitochondrial NADH:Ubiquinone oxidoreductase (complex I).

The respiratory complex I of mitochondria consists of some 40 different subunits which form an L-shaped structure. Perpendicular to a hydrophobic arm embedded in the inner mitochondrial membrane a peripheral arm protrudes into the matrix. Assembly of the complex as studied in the fungus Neurospora crassa involves the formation of discrete intermediates. The matrix arm and the membrane arm are formed independently of each other and are joined in the course of assembly. The membrane arm itself is formed by association of two assembly intermediates, a smaller of 200 kDa and a larger of 350 kDa. The latter is associated with two extra proteins of 84 and 30 kDa which are not constituent parts of mature complex I. Their primary structures show no similarity to known proteins. Mutants generated by disrupting the genes of either of the two proteins accumulate the matrix arm of complex I and the small membrane arm assembly intermediate, but are incapable of forming the large intermediate. In the wild-type, the extra proteins exclusively associate with the large membrane arm assembly intermediate. Pulse-chase labelling experiments showed that the two proteins are repeatedly involved in many assembly cycles of the intermediate. These results indicate that the two proteins are novel chaperones specific for complex I membrane arm assembly.

Amino Acid Sequence↗
PubMed1993

Aspartame is no more likely than placebo to cause urticaria/angioedema: results of a multicenter, randomized, double-blind, placebo-controlled, crossover study.

BACKGROUND: Anecdotes and single case reports have suggested that the high-intensity sweetener, aspartame, may be associated with allergic/hypersensitivity-type reactions. METHODS: We conducted a multicenter, placebo-controlled clinical study to evaluate individuals who had experienced urticaria and/or angioedema allegedly associated with ingestion of an aspartame-containing product. Despite extensive recruiting efforts over 4 years, only 21 subjects could be enrolled. After admission to clinical research units, subjects were given aspartame and placebo in a randomized, double-blind, crossover fashion. Subjects received, on different days, increasing doses (50, 300, 600 mg) of aspartame and placebo at 8:00 AM, 10:00 AM, and noon. Subjects who weighed less than 40 kg received one half of these doses. Conversion products of aspartame, aspartyl-phenylalanine diketopiperazine and beta-aspartame, were also included in the aspartame arm of the study. Positive reactions were defined as urticaria (hives with wheals 4 mm or more in diameter with a collective diameter of at least 15 mm or one or more hives with a wheal of 4 mm or greater with a flare of 8 mm or greater) or as angioedema. RESULTS: According to these criteria, four reactions were observed; two followed aspartame ingestion and two followed placebo ingestion (p = 1.00). The incidence of other adverse experiences was no different after aspartame versus placebo ingestion (p = 0.289). CONCLUSION: These results indicate that aspartame and its conversion products are no more likely than placebo to cause urticaria and/or angioedema reactions in subjects with a history consistent with hypersensitivity to aspartame.

Administration, Oral↗
PubMed1993

Validity and reproducibility of multi-test skin test device.

Thirty patients were skin tested by Multi-Test and Morrow Brown needle using antigens, histamine, glycerosaline, and blank controls to examine reproducibility and influence of positive reactions on adjacent negative controls. There was no evidence that histamine or strongly positive antigen reactions affected adjacent negative controls. Multi-Test was more reproducible, and preferred by patients over Morrow Brown.

Adolescent↗
PubMed1992

Geneva experience with the Ineraid multichannel cochlear implant.

Ineraid is a multichannel intracochlear implant of recent design that can provide high levels of speech recognition to totally deaf patients. We chose this device when it became available in 1985 because of our clinical and research interests. We had no commercial ties and could therefore critically assess the value of this implant in an array of patients, including congenital deafness, ossified cochleas and perilingual children.

Adolescent↗
PubMed1992

Immediate and delayed type hypersensitivity to malathion.

Between December 1989 and June 1990, 1,874 reports of alleged malathion application related illness from repeated spraying of a mixture of malathion corn syrup bait to eradicate a Mediterranean fruit fly infestation in Southern California were received by the Toxics Epidemiology Program of Los Angeles County. Among these complaints were 47 reports of urticaria, 38 reports of angioedema and 213 reports of a nonspecific skin rash. In order to determine whether these alleged skin reactions were the result of an immediate or delayed type of hypersensitivity reaction to malathion or to the corn syrup bait we studied ten subjects referred for testing by the local health department. All ten subjects had no reaction on patch testing. One child exhibited a positive reaction to the bait and one child had irritant reactions to malathion and to the bait. This study documented one case of a possible immediate IgE reaction to malathion bait. Due to the low participation rates in this study, no specific conclusions concerning the rate of sensitivity in the population can be drawn, although it appears that such reactions are uncommon.

Adult↗
PubMed1992

Effect of terfenadine in asthmatic patients.

The bronchodilator effect of terfenadine, 60-mg or 120-mg single dose, and 1 week twice daily dosing, was evaluated in 12 allergic asthmatic patients. When compared with baseline, FEV1 rose significantly for single dose 120 mg terfenadine at one, one and one-half, three, five and one-half, and six hours and for 60 mg terfenadine at three, five and one-half, six, and eight hours postdose. Variations in patient response were observed. At steady state, 120 mg terfenadine b.i.d. showed consistent improvement over placebo from three to 12 hours postdosing but no improvement in FEV1 was noted for terfenadine, 60 mg b.i.d. There no longer was a statistically significant difference in mean FEV1 or percent change from baseline. Thus, terfenadine proved to be a safe and a mild bronchodilator; however, tachyphylaxis might develop to the bronchodilator effect after 1 week of continuous b.i.d. dosing.

Asthma↗
PubMed1988

Noninvasive extratympanic electrical stimulation of the auditory nerve.

We have developed a noninvasive technique for extratympanic stimulation of the auditory nerve. 119 ears of 76 subjects with either normal, residual or no hearing were tested. 73% of the subjects with experience of hearing reported definite auditory sensations. Subjects with no certain experience of hearing could not describe accurately the nature of their sensations. Electrical stimulation of normal ears failed to elicit auditory sensations. These results compare well with those of promontory stimulation in cochlear implant candidates.

Adolescent↗
PubMed1986

Sustained-release theophylline preparations in asthmatic children. A short-term comparison of two products and the relationship of serum theophylline levels and pulmonary function changes.

In a four-week study, 20 children with chronic asthma were treated in a randomized, double-blind, crossover manner with two sustained-release theophylline preparations (Theo-Dur and Uniphyl) to compare their drug concentrations and clinical efficacy. In addition, the effects of serum theophylline concentration on results of pulmonary function tests (PFTs) were evaluated. Twelve-hour doses (to achieve serum concentrations between 10 and 20 mg/L) of each drug were given for two weeks. Diaries of asthma symptoms and peak flows were kept daily. After 14 days of each treatment, children returned for measurement of theophylline levels and PFTs over a 12-hour period. The two drugs were equally effective in clinically controlling asthma over the two weeks of treatment. Serum theophylline levels obtained over the 12-hour dosing periods were not significantly different. Uniphyl provided less (but not significantly) deviation between peak and trough levels. Analysis of individual patient data did not reveal a predictable relationship between serum theophylline concentrations and results of PFTs.

Adolescent↗
PubMed1985

Active immunization against hepatitis B: immunogenicity study in homosexual men.

In a group of 238 homosexual men a hepatitis B vaccine developed at the National Reference Center for Viral Hepatitis (Göttingen/Germany) was evaluated. The vaccine was well tolerated. Three intramuscular injections of inactivated HBsAg (subtype ad; 11300 Natl. Units/dose) induced antibody production in 89.7% of the subjects. Four participants exhibited signs of hepatitis B infection. Vaccine recipients younger than 30 years produced higher antibody levels than older vaccinees. More than one half of the subjects who had only anti-HBs (anti-HBc negative) prior to immunization did not show an anamnestic booster response but formed IgM-anti-HBs. Antibody levels were significantly lower in anti-HBs negative/anti-HBc positive recipients than in subjects who had only anti-HBs or no hepatitis B markers. Immunological studies of T and B cell function did not provide conclusive evidence for the underlying cause of the different immune responses.

Adult↗
PubMed1983

Rhinopharyngoscopy for the evaluation of allergic-immunologic disorders.

We have developed fiberoptic rhinopharyngoscopy as an important procedure for the evaluation of allergic and immunologic disorders. The procedure is useful for office practice, well tolerated and without serious complications. This paper outlines the technique for fiberoptic rhinopharyngoscopy, the pathology which can be identified, instruments available and our experience in nearly 100 patients.

Candidiasis↗