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Biomedical subjects

C Fischer

Publications and source records attributed to C Fischer.

At least 127 records · Page 7Linked to original sources
PubMed1999

[Angiography detection of closed palmar arcs].

PURPOSE: Angiographic evaluation of the prevalence of an anastomosis between the superficial and deep palmer arcs in our patients. MATERIALS AND METHODS: Between January 1st 1991 and December 31st 1997, all selectively performed angiographies of the upper extremities were evaluated retrospectively with special focus on an anastomosis between the superficial palmer arc (SPA) and the deep palmer arc (DPA). The indications for performing a selective angiography of the upper extremity were presurgical planning of a skin/muscle transplantation (n = 42), creation of a hemodialysis fistula (n = 4) and evaluation of vascular diseases such as vasculitis (n = 9), peripheral occlusive disease (n = 3) and M. Winiwarter-Buerger (n = 8). RESULTS: 66 selective angiographies of the palm of 60 patients (39 male, 21 female, mean age 52 years old) could be used for evaluation. Angiographies of both hands were performed in 6 patients. Closed superficial palmar arcs and closed deep palmar arcs were detected in 31.8% and 84.8% of the patients, respectively. CONCLUSIONS: The rates of anastomosed superficial and deep palmar arcs in our study are comparable with those of former angiographic investigations, but they are considerably lower than the rates based on anatomical or sonographical studies. Reasons for the discrepancy are discussed.

Adult↗
PubMed1999

[Intracranial cavernoma. Surgical results of 47 cases].

We report the surgical results in a series of 47 patients with cerebral cavernous malformation who had undergone surgery between 1973 and 1994, with a follow up ranging from 12 months to 24 years (mean: 4 years). They were divided in there groups according to their initial clinical presentation: epilepsy (31 cases), hemorrhage (11 cases) and neurological deficit (5 cases). Surgery consisted of cavernoma resection only (11 cases) or its extension to surrounding gliotic tissue (36 cases). Results are satisfactory: no surgical mortality, low morbidity (4 cases), no recurrent hemorrhage, seizures disappearance with anticonvulsant therapy stop (4 cases) or alleviation (20 cases). Only one patient died far from surgery (6 months) consequently to his initial bleeding, while all the others lead a normal active life. The therapeutic management, compared to the literature, pleads in favour of intentionally surgical attitude and gliotic tissue removal as often as reasonably possible.

Adolescent↗
PubMed1998

Acylation of the influenza hemagglutinin modulates fusion activity.

The influenza virus hemagglutinin (HA) contains three highly conserved cysteine residues at positions 551, 559, and 562 close to the carboxyl-terminus of the HA2 subunit which serve as palmitylation sites. Wild-type HA of influenza virus A/FPV/Rostock/34 (H7N1) and HA permutated by exchange of the acylated cysteine to serine residues were expressed in CV-1 cells by a SV40 vector system. Since density of immunostained HA on the cell surface measured by flow cytometric analysis did not differ between wild-type and acylation mutants, it was possible to compare acylation mutants and wild-type HA for their capacity to induce membrane fusion at low pH. The following observations were made: (1) lateral diffusion of a lipid-like fluorophore (R-18) from the erythrocyte membrane to the plasma membrane of cells expressing HA on the surface occurred equally well with mutants and wild type. (2) Diffusion of a low-molecular-weight fluorescent water-soluble probe (calcein) from erythrocytes into the cytoplasm of HA-expressing cells was not altered either. (3) However, depending on the position and the number of the deleted acylation sites, the mutants showed a reduced ability to induce syncytia. The data indicate that deacylation of the cytoplasmic tail has no measurable effect on the capacity of HA to induce membrane fusion and pore formation but that it suppresses syncytia formation.

Acylation↗
PubMed1998

Interplay between humans and infective agents: a population genetic study.

The genetic composition of present day human populations is determined largely by the interaction between the human host and infective agents. Therefore, theoretical analysis of the host-infective-agent system is required in order for us to be able to understand human evolution. Classical population genetics has been confined largely to analysing the interplay of various mechanisms, such as selection, mutation and drift, in one species at a time. Unfortunately, there have been few studies of such interactive systems. In the present investigation, these studies have been enlarged, with problems of human genetics in mind, by mathematical examination of a model in which a diploid host with three alleles interacts with a haploid infective agent with two alleles. The results are compared with those obtained from simpler models analysed in the past. The assumptions inherent in such "gene for gene" models and our results are discussed. An increase in the number of alleles appears to enhance the chances for the establishment of permanent genetic polymorphisms, improving genetic "elasticity" of a population for coping with changing challenges by various infective agents. Interaction between two haploid species leads to a loss of polymorphism in both of them and, hence, to a severe loss of evolutionary elasticity. The hypothesis that the evolution of diploidy might have been favoured by a selective advantage of diploid organisms interacting with environmental challenges, such as infective agents, is supported.

ABO Blood-Group System↗
PubMed1998

Murphy's law in cardiac surgery.

We report the case of a 41-year-old man who underwent heart transplantation after suffering from aortic dissection during the implantation of a biventricular assist device for heart failure after coronary artery bypass grafting. The biventricular assist device had to be operated by hand for 10 hours because of a technical defect. In the end perseverance won out and the patient is now doing well at 2.5 years of follow-up.

Adult↗
PubMed1998

Laparoscopic nephrectomy: the experience of the laparoscopy working group of the German Urologic Association.

PURPOSE: The centers of the laparoscopy working group of the German Urologic Association collected data to prove the efficacy, safety and reproducibility of laparoscopic nephrectomy. MATERIALS AND METHODS: At 14 centers 482 laparoscopic nephrectomies have been performed until December 1996 via a transperitoneal approach in 344 (71%) and a retroperitoneal approach in 138 (29%). All 482 laparoscopic nephrectomies were performed by a total of 20 surgeons with an average of 24 procedures per surgeon (range 4 to 105). The indications for nephrectomy were benign renal pathology in 444 patients (92%), including renovascular disease in 28%, hydronephrosis in 20%, reflux nephropathy in 15%, chronic pyelonephritis in 12%, end stage nephrolithiasis in 11%, renal dysplasia in 4% and renal tuberculosis in 1%. Of the remaining 38 patients (8%) laparoscopic radical nephrectomy was performed for renal cell carcinoma in 5% and for upper tract transitional cell carcinoma in 3%. RESULTS: Operating time depended mainly on the pathology of the kidney (that is small dysplastic organ versus large hydronephrosis) and the learning curve of the surgeon. However, the average operating time did not vary significantly among the different centers (maximum 277.6 and minimum 81.9 minutes). Intraoperative or perioperative complications were noted in 29 patients (6.0%), including bleeding in 22 (4.6%), bowel injury in 3, hypercarbia in 2 and pleura lesion in 1 and pulmonary embolism in 1. The conversion rate was 10.3% (bleeding, bowel injury, difficult dissection), including 4 patients with renal tuberculosis, 2 with xanthogranulomatous nephritis, and 1 each following renal trauma and embolization. The re-intervention rate was 3.4% due to bleeding in 6 cases, abscess formation in 3, intestinal stenosis in 2 and a pancreatic fistula and port hernia in 1. Mean hospital stay was 5.4 days. CONCLUSIONS: Laparoscopic nephrectomy has become a well established procedure in those urology departments focusing on laparoscopy. The indications and results are reproducible at these centers. However, for patients with severe perinephritis (that is renal tuberculosis, xanthogranulomatous nephritis, posttraumatic atrophy) a higher likelihood of open conversion must be considered.

Adolescent↗
PubMed1998

The Ets-1 transcription factor is required for the development of natural killer cells in mice.

In this report we have investigated the role of the Ets-1 transcription factor in the differentiation of the NK cell lineage in mice. Splenic NK cells express high levels of Ets-1. Ets-1-deficient mice produced by gene targeting developed mature erythrocytes, monocytes, neutrophils, and T and B lymphocytes. However, spleens from the Ets-1-deficient mice contained significantly reduced numbers of natural killer (NK) cells, and splenocytes from these mice lacked detectable cytolytic activity against NK cell targets in vitro. Moreover, unlike wild-type animals, Ets-1-deficient mice developed tumors following subcutaneous injection of NK-susceptible RMA-S cells. These NK cell defects could not be correlated with defects in the expression of IL-12, IL-15, and IL-18 or the IL-2 or IL-15 receptors. Thus, Ets-1 defines a novel transcriptional pathway that is required for the development of the NK cell lineage in mice.

Animals↗
PubMed1998

A stereoelectroencephalographic (SEEG) study of light-induced mesiotemporal epileptic seizures.

PURPOSE: This study explored the mechanism of light-induced complex partial seizures by using ictal intracerebral recordings in a patient with refractory epilepsy of the right temporal lobe. METHODS: Presurgical evaluation of this patient was realized by means of video-EEG recordings, WADA test, magnetic resonance imaging (MRI), F18-deoxyglucose and C11-flumazenil positron emission tomography (PET) interictal neuroimaging data, and stereoelectroencephalographic (SEEG) ictal recordings. RESULTS: SEEG investigations demonstrated the right mesiotemporal origin of all the patient's seizures. This result was confirmed by a successful right temporal lobectomy. Moreover, SEEG recordings revealed a frequent interictal spiking activity in the right occipital visual cortex that was undetectable on scalp recordings. However, the occipital cortex was not involved at the onset of mesiotemporal ictal discharges and was not hyperresponsive to focal electrical stimulation. CONCLUSIONS: This study shows that, in spite of interictal occipital spiking, the photosensitivity of mesiotemporal seizures can be observed in both the absence of occipital cortex involvement during ictal discharges and demonstrable hyperexcitability of the occipital cortex to light or direct electrical stimulation.

Adult↗
PubMed1998

Elongation of the cytoplasmic tail interferes with the fusion activity of influenza virus hemagglutinin.

The hemagglutinin (HA) of fowl plague virus was lengthened and shortened by site-specific mutagenesis at the cytoplasmic tail, and the effects of these modifications on HA functions were analyzed after expression from a simian virus 40 vector. Elongation of the tail by the addition of one to six histidine (His) residues did not interfere with intracellular transport, glycosylation, proteolytic cleavage, acylation, cell surface expression, and hemadsorption. However, the ability to induce syncytia at a low pH decreased dramatically depending on the number of His residues added. Partial fusion (hemifusion), assayed by fluorescence transfer from octadecylrhodamine-labeled erythrocyte membranes, was also reduced, but even with the mutant carrying six His residues, significant transfer was observed. However, when the formation of fusion pores was examined with hydrophilic fluorescent calcein, transfer from erythrocytes to HA-expressing cells was not observed with the mutant carrying six histidine residues. The addition of different amino acids to the cytoplasmic tail of HA caused an inhibitory effect similar to that caused by the addition of His. On the other hand, a mutant lacking the cytoplasmic tail was still able to fuse at a reduced level. These results demonstrate that elongation of the cytoplasmic tail interferes with the formation and enlargement of fusion pores. Thus, the length of the cytoplasmic tail plays a critical role in the fusion process.

Amino Acids↗
PubMed1998

[Information, a resource for future bone marrow allografts].

From a legislative point of view, the allograft of bone marrow is considered as an organ transplant. It consists in "replacing a diseased or deficient marrow with a healthy marrow removed on a compatible living donor." This treatment has significant repercussions for the patient. Will he find, in his circle, the resources which will enable him to face the changes imposed by the marrow graft? The information can then be a way to meet the needs of the patient. Our study is based on questionnaires sent to 55 adults who underwent an allograft. Thanks to the results, we could highlight the most favourable moment for information, the person most capable of giving it, the precise content and the way best suited to the needs of the patient.

Adaptation, Psychological↗
PubMed1998

[Auditory perception disorders due to bilateral cortical lesions. An electrophysiology study].

A 78-year-old right handed man with a past history of atrial fibrillation developed in November 1994, a slight right hemiparesis with aphasia which cleared over one month. Head CT scan showed a left middle cerebral artery infarct involving the posterior part of the temporal lobe. In September 1995, a second stroke occurred. Head CT scan revealed a recent right middle cerebral artery infarct within the posterior part of temporal cortex. Auditory agnosia was diagnosed. Auditory evoked potentials recording showed bilateral dysfunction of central auditory pathways mainly over the right hemisphere. Clinical data and evoked potentials suggest that auditory agnosia might be related to the right temporal lobe damage. This later is involved in linguistic processes as suggested by positron emission tomography studies.

Aged↗
PubMed1997

Novel splice donor site mutation in the cardiac myosin-binding protein-C gene in familial hypertrophic cardiomyopathy. Characterization Of cardiac transcript and protein.

Familial hypertrophic cardiomyopathy is a disease generally believed to be caused by mutations in sarcomeric proteins. In a family with hypertrophic cardiomyopathy linked to polymorphic markers on chromosome 11, we found a new mutation of a splice donor site of the cardiac myosin-binding protein-C gene. This mutation causes the skipping of the associated exon in mRNA from lymphocytes and myocardium. Skipping of the exon with a consecutive reading frame shift leads to premature termination of translation and is thus expected to produce a truncated cardiac myosin-binding protein-C with loss of the myosin- and titin-binding COOH terminus. However, Western blot analysis of endomyocardial biopsies from histologically affected left ventricular myocardium failed to show the expected truncated protein. These data show for the first time that a splice donor site mutation in the myosin-binding protein-C gene is transcribed to cardiac mRNA. Truncated cardiac myosin-binding protein-C does not act as a "poison polypeptide," since it seems not to be incorporated into the sarcomere in significant amounts. The absence of mutant protein and of significantly reduced amounts of wild-type protein in the presence of the mutated mRNA argues against the "poison protein" and the "null allele" hypotheses and suggests yet unknown mechanisms relevant to the genesis of chromosome-11- associated familial hypertrophic cardiomyopathy.

Blotting, Western↗