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Biomedical subjects

H Fischer

Publications and source records attributed to H Fischer.

At least 163 records · Page 9Linked to original sources
PubMed1997

Reduced activity in the extrastriate visual cortex of individuals with strabismic amblyopia.

In order to examine the relationship between reduced visual acuity in human strabismic amblyopia and the cortical activation pattern, we studied, by use of positron emission tomography (PET) and the H2(15)O bolus technique, changes in the regional cerebral blood flow (rCBF) induced by monocular visual stimulation of 8 individuals with this disorder. Individual amblyopic thresholds for monocular detection of the checkerboard pattern were employed as stimuli for both eyes during PET scans. Statistical analysis of subtracted images showed significant increases in rCBF (P < 0.05) by the stimulation of the sound eye localized bilaterally to Brodmann's areas (BAs) 17-19. The cortical response evoked by the amblyopic eye was significantly reduced (P < 0.05) in the ipsilateral BAs 18, 19. These results suggest that the reduction in contrast sensitivity (pattern vision) in amblyopia is coupled with deactivation in identifiable regions of occipital visual areas, including ipsilateral BAs 18,19.

Adult↗
PubMed1997

Botulinum neurotoxin injection after total laryngectomy.

BACKGROUND: One of several causes of tracheoesophageal puncture (TEP) speech failure after total laryngectomy is disturbance in relaxation of the pharyngoesophageal (PE) segment. We introduce the use of chemical denervation of the PE segment through botulinum neurotoxin (Botox) injection to improve TEP speech. METHODS: An analysis was performed on eight patients who received Botox injections for TEP speech problems after total laryngectomy at the University of Iowa between June 4, 1991 and August 8, 1994. Retrospective chart review identified the evolution of pretreatment evaluation and injection technique which became standardized in April 1992. Prospective evaluation of results was recorded by a single speech pathologist who subjectively identified the response to Botox in all patients and recorded pressure readings at the tracheostoma site during speech in 6 patients. RESULTS: Seven of the eight patients were noted to have improved TEP speech following injection. Five of these seven patients experienced substantially improved speech, three of whom had no ability to produce speech prior to the Botox injection. CONCLUSION: Botox injection is a safe and effective method of improving TEP speech in selected patients with disturbed relaxation of pharyngoesophageal segment.

Adult↗
PubMed1997

Usefulness of detection of minimal residual disease by 'hypermetaphase' fluorescent in situ hybridization after allogeneic BMT for chronic myelogenous leukemia.

Hypermetaphase FISH (HMF), a molecular cytogenetic procedure combining the long term mitotic arrest of bone marrow cultures with detection of a specific chromosomal rearrangement by fluorescence in situ hybridization (FISH), has recently been shown to be effective in determining the frequency of Philadelphia chromosome positive (Ph+) cells in the bone marrow of chronic myelogenous leukemia (CML) patients undergoing treatment. By combining the probe for the Ph chromosome with one for the detection of the X chromosome, we used HMF to monitor the presence of malignant cells within the emerging host cell population in the marrow of a CML patient that had undergone sex-mismatched allogeneic bone marrow transplantation. In successive studies, we detected 0.5% and 1.75% Ph+ cells, respectively, confirmed by Western blot analysis for p210 protein. These readings occurred concordantly with a repopulation of host-derived diploid female cells. Standard G-band cytogenetic analyses did not detect any Ph+ cells at these time points. Intervention with donor lymphocyte infusion reinduced complete remission. This experience indicates that HMF is useful to identify low levels of repopulation by Ph+ cells in the marrow post-BMT at a stage when intervention is most efficacious.

ABO Blood-Group System↗
PubMed1997

[The computed tomographic determination of intra-abdominal fat volume by single-layer measurement].

PURPOSE: Several studies emphasised the importance of the relationship between intra-abdominal and total body adipose tissue as a risk factor for the development of metabolic or cardiovascular diseases. Therefore, the aim of the present study was to examine whether a single-scan computed tomography is able to determine the whole intra-abdominal fat volume with high accuracy and reproducibility. MATERIALS AND METHODS: Regions of interests (ROIs) were drawn manually for measuring intra-abdominal fat in 51 unsuspicious abdominal CT. RESULTS: The sexual differentiation of adipose tissue already described in a lot of studies could be confirmed in this study. Fat still predominates in females in lower half of the body (gynecoid obesity). In men it predominates in the upper half (android obesity). Significant correlation concerning measuring the whole intra-abdominal fat volume could be found in L1-level in women (r = 0.992) and in L2-level in men (r = 0.992). Measurement of a single scan enables us to assess whole intra-abdominal fat volume due to a special formula. CONCLUSION: The determination of intra-abdominal fat measured by a single-scan computed tomography is a procedure associated with high accuracy and reproducibility.

Adipose Tissue↗
PubMed1997

Detection of a de novo duplication of 1q32-qter by fluorescence in situ hybridisation in a boy with multiple malformations: further delineation of the trisomy 1q syndrome.

We report a dysmorphic boy with a de novo partial trisomy 1q. The boy has microcephaly, bilateral cleft lip and palate, low set and dysmorphic ears, brain anomalies, pulmonary stenosis, duodenal obstruction, dysplastic kidneys, and bifid thumbs. The trisomic segment 1q32-qter is duplicated with an inverted insertion at 1p36.3. The aberration was initially detected at amniocentesis and confirmed and defined by GTG banding, chromosome microdissection, and FISH on postnatal blood samples. The parents had normal karyotypes. De novo partial duplications of chromosome 1q have rarely been reported. Comparison of our patient with other published pure trisomy 1q cases showed similarities which allowed the further delineation of the trisomy 1q syndrome.

Chromosome Aberrations↗
PubMed1997

Evidence of altered cerebral blood-flow relationships in acute phobia.

Functional cerebral guiding and integrating systems may be revealed by analyzing the covariation of regional cerebral blood flow (rCBF). Positron emission tomography (PET) was used to measure absolute rCBF in 14 volunteers with specific phobia and 6 nonphobic controls, when exposed to videos containing phobia-relevant and neutral scenes. A fear reaction and increased covariation between absolute rCBFs was observed during phobia-relevant as compared to neutral stimulation in phobics only. In controls fear was not elicited and rCBF covariation was not influenced by stimulus condition, being similar to the pattern observed in phobics during neutral stimulation. We suggest the rCBF correlative pattern during phobic fear to reflect fear-related activation of distinct neuronal pathways that involves the amygdala, the thalamus, and the striatum. We theorize that these pathways are activated also by uncontrolled emotions in diverse conditions, like posttraumatic stress disorder, panic disorder, and schizophrenia.

Acute Disease↗
PubMed1997

Disturbed gastric motor activity in patients with human immunodeficiency virus infection.

BACKGROUND: Human immunodeficiency virus (HIV) infection is accompanied by a wide spectrum of disorders that affect the central and peripheral nervous system. Damage to the peripheral and central nervous system, including its autonomic division, may become manifest at any stage of the disease. METHODS: Twenty HIV-positive patients with abdominal complaints like dyspepsia, dysphagia, vomiting, and nausea underwent several function tests to determine oesophageal motility, gastric motor and electric activity, and gastric emptying rate. The CDC (Center for Disease Control) classification was used to determine the stage of the disease, which varied from B2 to C3. Before gastric motility examinations all patients underwent endoscopy of the upper gastrointestinal (GI) tract, and none of them showed any morphologic changes of the stomach or oesophagus. Biopsy specimens taken during upper GI endoscopy did not show any histologic alterations of the gastric or oesophageal mucosa. RESULTS: Manometry of the antrum showed an unchanged postprandial (after 200 ml liquid, caloric meal) motility index (MI) when compared with the fasting period (mean fed MI, 174 +/- 43; mean fasting MI, 136 +/- 51). The same was seen for frequency, amplitude, and duration of antral contractions. The electrogastrographic recordings showed basal rhythm of 3 cpm, and no significant changes of the electric pattern were observed postprandially. The amplitude of electric oscillations (power content) significantly increased postprandially when compared with the fasting period. The gastric emptying rate of liquids, measured by means of the 13C-acetate breath test, was faster in HIV patients than in healthy controls. On the other hand, in HIV patients the scintigraphically determined emptying rate of solids was significantly delayed compared with the normal values. There were no significant differences in the oesophageal motility pattern with regard to the amplitude, duration, and propagation of peristaltic waves when compared with the values obtained from healthy volunteers. CONCLUSION: Our results suggest that HIV-associated visceral neuropathy may present already in relatively early stages of infection and may contribute to abdominal symptoms that occur frequently in these patients.

Adult↗
PubMed1997

The impact of T-cell depletion on the effects of HLA DR beta 1 and DQ beta allele matching in HLA serologically identical unrelated donor bone marrow transplantation.

Unrelated donor bone marrow transplants have been associated with relatively high rates of acute graft-vs.-host disease and treatment-related mortality. These complications reflect histo-incompatibility between donor and recipient. Molecular technology has recently been applied to HLA typing to identify alleles not distinguishable with serologic typing techniques. We report results in 92 unrelated marrow transplant recipients who were HLA seroidentical with donor HLA-A, -B, and -DR antigens and assess the effect of DR beta 1 and DQ beta compatibility using sequence specific oligonucleotide primers. Forty-eight patients received T-cell depleted marrow grafts, and 44 received unmodified grafts. Among recipients of unmodified marrow grafts, matching for both DR beta 1 and DQ beta reduced the rate of grade 3-4 acute graft-vs.-host disease to 38 +/- 20% vs. 73 +/- 20% among recipients mismatched for either allele (p = 0.02). This difference was not observed in recipients of T-cell depleted marrow grafts. Multivariate analysis confirmed matching for both DR beta 1 and DQ beta loci (p = 0.015), and receiving a T-cell depleted graft (p = 0.008) independently predicted for reduced risk of grade 3-4 acute graft-vs.-host disease. In conclusion, both DR beta 1 and DQ beta appear biologically important for development of acute graft-vs.-host disease in patients receiving unmanipulated marrow grafts for unrelated donor transplant.

Adult↗
PubMed1997

Cerebral blood flow during anxiety provocation.

It has been suggested that traumatic reactions result from the failure to integrate the trauma with existing cognitive schemata, whereas phobias represent biologically influenced adaptation patterns. This implies that central nervous system (CNS) organization of traumatic reactions may differ from that of phobic reactions. In this article, we review our previously published work on anxiety and regional cerebral blood flow (rCBF). By using positron emission tomography and [(15)O]-butanol, relative rCBF was determined in 14 subjects with simple animal phobias exposed to visual phobogenic stimuli and in 6 bank officials exposed to a video showing an armed bank robbery that they recently witnessed. Subjective and physiologic indices of fear and anxiety were elevated by the activation condition in both groups. Phobic stimulation elevated rCBF bilaterally in the secondary visual cortex compared with neutral stimulation but reduced rCBF in the hippocampus and in the prefrontal, orbitofrontal, temporopolar, and posterior cingulate cortex. Compared with neutral stimulation, video of a robbery increased rCBF bilaterally in the primary and secondary visual cortex, the posterior cingulate, and the left orbitofrontal cortex. Decreased rCBF was evident in Broca's area, the left angular gyrus, the left operculum, and the secondary somatosensory cortex. Hence, visually induced fear and anxiety are associated with alterations in limbic, paralimbic, and cortical brain regions that are of relevance for cognition and affect.

Anxiety↗
PubMed1996

Tacrolimus and minidose methotrexate for prevention of acute graft-versus-host disease after matched unrelated donor marrow transplantation.

Thirty adults with leukemia or lymphoma undergoing marrow transplantation from HLA-compatible unrelated donors received tacrolimus (FK506), a new immunosuppressive macrolide lactone, and minidose methotrexate to prevent acute graft-versus-host disease (GVHD). The group had a median age of 36 years (range 21 to 49 years). Twenty-four patients had advanced disease, and 11 were resistant to conventional therapy. Tacrolimus was administered at 0.03 mg/kg/d intravenously (i.v.) by continuous infusion from day -2, converted to oral at four times the i.v. dose following engraftment, and continued through day 180 posttransplant. Methotrexate 5 mg/m2 was given i.v. on days 1, 3, 6, and 11. All patients engrafted. Grades 2-4 GVHD occurred in 34% (95% CI, 17% to 52%), and grades 3-4 GVHD in 17% (95% CI, 3% to 31%). Mild renal toxicity was common before day 100; 63% of patients had a doubling of creatinine, and 52% had a peak creatinine greater than 2 mg/dL, but only one patient was dialyzed. The median last i.v. dose of tacrolimus was 53% of the scheduled dose, and the median oral dose on day 100 was 41% of that scheduled. Overall survival at 1 year was 47% (95% CI, 27% to 66%). We conclude that tacrolimus can be combined safely with minidose methotrexate, and the combination has substantial activity in preventing acute GVHD after unrelated donor marrow transplantation.

Actuarial Analysis↗
PubMed1996

In growth cones of rat cerebral neurons and human neuroblastoma cells, activation of protein kinase C causes a shift from filopodial to lamellipodial actin dynamics.

In cultures of rat cerebral neurons addition of the protein kinase C (PKC) activator 1,2-dioctanoyl-s,n-glycerol (diC8; 5 microM) induces a transient elongation of filopodia which is followed by a striking enhancement of lamellar protrusions. After 30-40 min, lamellipodia are slowly retracted, filopodia reappear and become predominant again. The reappearance of filopodia is accelerated by addition of the potent PKC-inhibitor RO-31-8220 (2 microM). A similar transient promotion of lamellar protrusive activity is obtained in SH-SY5Y neuroblastoma cells upon stimulation by acetylcholine or diC8. Immunostainings showed that the new space created by extending actin-driven lamellipodia is rapidly entered by microtubules. Preincubation with or permanent presence of RO-31-8220 totally inhibits both filopodial and lamellipodial protrusive activity. The data suggest that both filopodial and lamellipodial protrusion require active PKC, however of different levels of activation.

Actins↗
PubMed1996

Functional neuroanatomy of robbery re-experience: affective memories studied with PET.

Using positron emission tomography (PET) and [15O]butanol, regional cerebral blood flow (rCBF) was determined in six bank officials during exposure to a video of a jointly experienced armed bank robbery, and a control video. Besides elevating subjective and physiological indices of anxiety, traumatic stimulation increased rCBF bilaterally in the primary and secondary visual cortex, the posterior gyrus cinguli and in the left orbitofrontal cortex compared with that during the control stimulation. Decreased rCBF was found in Broca's area, the left angular gyrus, the left operculum and the secondary somatosensory cortex. Thus, the stress induced by visual re-experience of a robbery is associated with altered activity in paralimbic and cortical brain regions of relevance for cognition and affect.

Adult↗
PubMed1996

Evolution of legumin genes: loss of an ancestral intron at the beginning of angiosperm diversification.

The polymerase chain reaction was used to survey gymnosperm legumin genes. Characterization of 46 cloned amplificates, differing in sequence and size (1.2-1.6 kb), revealed the ubiquitous occurrence of legumin genes and their organization in small subfamilies in the 22 species investigated. The 3' portions of the genes, coding for the legumin beta-polypeptides, show a highly conserved intron/exon structure divergent from those of angiosperms: an additional intron (intron IV) uniformly interrupts the region coding for the C-terminal part of the beta-polypeptides. Phylogenetic analysis of the respective coding sequences as well as the organization of the Magnolia B14 legumin gene also investigated here both indicate that intron IV is ancestral and was lost during early angiosperm evolution. Taking into account the intron/exon structures from all legumin genes known, our results suggest that legumin genes evolved by subsequent loss of introns, providing also further evidence for a common origin of legumins and vicilins.

Amino Acid Sequence↗