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Biomedical subjects

P Marx

Publications and source records attributed to P Marx.

At least 73 records · Page 4Linked to original sources
PubMed1993

Cerebral ischemia induced by compression tests during transcranial Doppler sonography.

Compression tests performed during transcranial Doppler sonography are intended for support in identifying vessels and measuring collateral circulation within the circle of Willis. The resulting information is thought to be valuable in patients with extracranial carotid stenoses, especially for planning carotid and extra-/intracranial bypass surgery. In a retrospective analysis of a series of 380 cases, two patients with symptomatic carotid artery stenoses suffered three compression-induced focal cerebral ischemias. In two instances, these ischemias started under compression. The resulting deficits were reversible. One patient developed an additional and persisting motor deficit whose onset was delayed. The diagnostic benefit of compression tests is not established nor its risk well defined. They should not be used routinely.

Aged↗
PubMed1993

Transfected c-Ha-ras oncogene enhances karyotypic instability and integrates predominantly in aberrant chromosomes.

A human colon tumor cell line, SW480, was transfected with the c-Ha-ras oncogene, the wild type c-Ha-ras gene, or the pSV2neo plasmid. Cytogenetic analysis and localization of chromosome integration sites were combined in an attempt to analyze the effects of transfection with the c-Ha-ras oncogene on the karyotype. All transfected cell lines showed new clonal chromosome abnormalities present in all cells, ranging from three new aberrations in pSV2neo-transfected SW480 cell lines to eight in c-Ha-ras oncogene-transfected SW480 cell lines. The level of expression of c-Ha-ras mRNA after transfection with the c-Ha-ras oncogene was positively correlated with increased genetic instability, reflected in enhanced karyotypic instability. A combination of banding and fluorescence in situ hybridization (FISH) was used to identify chromosome integration sites. Plasmids containing ras integrated predominantly in new structurally rearranged chromosomes (five of eight). Three of five integration sites in new structurally rearranged chromosomes were localized at or near translocation breakpoints situated in telomeric regions. Specific chromosomes were not involved in the chromosome rearrangements. The results indicate that 1) enhanced expression of c-Ha-ras mRNA correlates with an increase in genetic instability in c-Ha-ras oncogene-transfected SW480 cell lines, and 2) that no specific integration site was observed but ras-containing plasmids were located predominantly in aberrant chromosomes near or at translocation breakpoints involving telomeric bands.

Chromosome Aberrations↗
PubMed1993

Reliability of in vivo volume measures of hippocampus and other brain structures using MRI.

Volume reductions of the hippocampus are associated with Alzheimer's disease, schizophrenia, and epilepsy. We used clinically available MRI methods (2D acquisition; inversion recovery and calculated T2 images; 3 mm contiguous slices) that optimize image contrast, quality, and resolution and standardized positioning protocols to maximize the in vivo accuracy (test-retest reliability) of brain volume measurements in volunteers who were scanned two or three times. Volunteers were scanned in the same MRI instrument (intrascanner reliability) as well as in two different instruments (interscanner reliability). A single rater obtained brain volume measures of seven contiguous slices centered on the anterior commissure. The in vivo intrascanner reliability for measures of anterior hippocampus and ventricular volumes was very good, with reliability coefficients [intraclass r (rxx)] ranging between .855 and .997, and a median coefficient of variation (CV) of 6.4%. Reliability was good for amygdala (rxx of .740 and .764) and for total frontal and temporal lobe volumes and white matter volume measures (rxx ranging between .640 and .823, median coefficient of variation was 3.2%). Overall, interscanner reliability was also good. We discuss the implications of our results relative to the possible clinical utility of hippocampal quantification and the feasibility of prospective studies aimed at quantifying progressive neurodegeneration.

Adult↗
PubMed1993

[Cerebral infarct caused by compression of the carotid artery in an alcohol intoxicated patient].

A 49 year-old woman developed a left sided hemiparesis with hemineglect after lying in an intoxicated condition for approximately half an hour with the right side of her neck on the metal edge of her bed. Dopplersonography of the intra- and extracranial vessels showed no abnormality of blood flow. On the right side of the neck a strangulation mark 8 cm of length was visible for several weeks. The CCT scan initially showed slight oedema. After 6 weeks changes corresponding to selective parenchymal necrosis were to be seen predominantly in the territory of the right middle cerebral artery.

Alcoholic Intoxication↗
PubMed1992

Human interferon consensus sequence binding protein is a negative regulator of enhancer elements common to interferon-inducible genes.

The promoter regions of many interferon-inducible genes share a short DNA sequence motif, termed the interferon consensus sequence (ICS) to which several regulatory proteins bind. A murine cDNA which encodes an ICS binding protein has been reported (M-ICSBP). The cloning of the human homologue of ICSBP (H-ICSBP) is described. H-ICSBP shares high sequence homology with its murine cognate. The derived sequence of H-ICSBP reveals restricted homology within the first 120 amino acids to three other interferon regulatory factors, IRF-1, IRF-2, and ISGF3 gamma. Truncated ICSBP lacking the first 33 amino-terminal amino acids fails to bind to the ICS, indicating that at least part of the DNA binding domain is located within the well conserved amino terminus. H-ICSBP is expressed exclusively in cell lines of hematopoietic origin. The results of transient transfection assays carried out either in hematopoietic or nonhematopoietic cells suggest that ICSBP acts as a negative regulatory factor on ICS-containing promoters. Furthermore, either interferon-gamma (IFN-gamma) or IFN-beta can alleviate the repression mediated by ICSBP. Therefore, ICSBP may be involved in maintaining submaximal transcriptional activity of IFN-inducible genes in hematopoietic cells. IFN treatment would then alleviate repression allowing maximal transcriptional activity of these genes.

Amino Acid Sequence↗
PubMed1992

Genital secretory immune response to chronic simian immunodeficiency virus (SIV) infection: a comparison between intravenously and genitally inoculated rhesus macaques.

The humoral and genital secretory immune response to chronic SIV infection was compared between female Rhesus macaques inoculated by i.v. or intravaginal routes. Total IgG levels in serum were 10-fold higher in SIV-infected animals when compared with uninfected controls. Vaginal washes from normal macaques contained predominantly IgA and IgG, while those from SIV-infected animals contained high levels of IgG. The SIV-infected animals had high titres of SIV-specific IgG in serum, with lower but detectable IgA and IgM responses. The genital secretory immune response to SIV was similar in intravenously and intravaginally inoculated animals. The anti-SIV response in the vaginal washes consisted mainly of IgG. Within the lamina propria of the reproductive tract of animals chronically infected with SIV there were essentially no IgA or IgG plasma cells and only a small number of IgM plasma cells, while two normal animals had large numbers of IgA plasma cells. These results suggest that the mucosal immune system of the female reproductive tract is impaired in chronic SIV infection.

Administration, Intravaginal↗
PubMed1992

Thoracic splenosis presenting with hemoptysis.

Thoracic splenosis (post-traumatic autotransplantation of splenic tissue) is rare and generally asymptomatic. We report a patient with thoracic splenosis presenting with repeated hemoptysis. The blood supply of the hypervascular splenic transplants originated from a bronchial and an intercostal artery. Hemoptysis improved after surgical exeresis of splenosis. Recognizing splenosis presenting with hemoptysis is important, since percutaneous embolotherapy could be hazardous because of the risk of ectopic splenic tissue infarction.

Chronic Disease↗
PubMed1992

2,5-Hexanedione is a potent gliatoxin in in-vitro cell cultures of the nervous system.

Of the metabolites of hexane, 2,5-hexanedione (2,5 HD) has the strongest neurotoxic effect. There is a wealth of experimental studies in animals showing an axonotoxic mechanism consisting of an accumulation of 10 nm neurofilaments. Only few studies deal with a possible action of 2,5-HD on Schwann cells, glia cells or both. Pure neurons, pure glia and mixed cultures prepared from dorsal root ganglia (DRG) of chick embryos were studied in this model. DRG were chosen because they constitute a linkage between the peripheral and central nervous system and provide the additional advantage of containing only few defined glial and neuronal cell types. Additionally, pure neuronal cultures of sympathetic ganglia and mixed cultures of spinal cord and brain were prepared. In cultures of the different parts of the nervous system investigated, we observed at a concentration of 0.25% 2,5-HD massive toxic alterations of glial cells, whereas neurons and neurites were virtually unaffected.

Animals↗
PubMed1992

Specific neurotoxic effects of different organic solvents on dissociated cultures of the nervous system.

Pure neurons were prepared from dorsal root ganglia (DRG) of 8 day old chick embryos (E8). The substances tested in this model were pure n-hexane, 2.5-hexanedione (2.5 HD) and methyl-ethyl-ketone (MEK). Differentiated cultures were exposed to these neurotoxins after two days in culture and then examined over a period of up to one week. For all three substances a specific neurotoxic effect could be demonstrated: (i) n-Hexane mainly altered the neurites, leading to focal swellings and in a second step to degenerative changes in glial cells; (ii) 2.5 HD had a minor effect on neurons and proved to be mainly gliatoxic; (iii) MEK primarily affected the neurons by swelling and disintegration of the cell body.

Animals↗
PubMed1991

[Diagnosis and prognosis of carotid artery stenosis].

The diagnosis of a carotid stenosis inevitably includes a neurological examination as well as CCT or MRI of the brain. Typical neurological and neuropsychological symptoms and signs as well as syndromes are described according to the vascular supply areas of the brain. CCT as well as MRI may identify cerebral infarction or other diseases and additionally give some information with regard to the underlying etiology or pathogenesis of an infarct. Satisfactory non-invasive demonstration of the carotid and vertebral arteries including their intracranial branches can be achieved by the use of sonographic methods (Dopplersonography, B-mode imaging, Duplex and colour-coded systems). Additionally, transcranial Dopplersonography is mandatory in most instances. Cerebral angiography is only justified preoperatively or for a disease which cannot be diagnosed reliably by other means, eg. cerebral venous thrombosis. The prognosis of a carotid stenosis depends not only on the degree of luminal narrowing and the shape of the stenosis but also on the clinical status of the patient (asymptomatic or symptomatic carotid stenosis, accompanying coronary artery disease etc.). Prophylactic treatment implies therapy of risk factors as well as antiaggregation, anticoagulation and carotid endarterectomy in selected cases.

Carotid Stenosis↗
PubMed1991

Neurological deterioration under isovolemic hemodilution with hydroxyethyl starch in acute cerebral ischemia.

In a prospective study, we randomly allocated 70 patients with acute ischemic stroke to two therapy groups. Up to interim analysis, 33 patients underwent bloodletting, with simultaneous infusion of an identical volume of hydroxyethyl starch (10%, 200/0.5). The target hematocrit was 35%. A control group of 37 patients did not receive hemodilution. Apart from an unequal sex distribution, the two groups were comparable with regard to age, cardiovascular risk factors, and medical history. In the hemodilution group, the mean hematocrit fell from 44.4% to 37.7%. After 14 days, improvement on the neurological score scale was 3.3 points in the hemodilution group compared with 6.5 points in the control group (p = 0.12). Subgroups with early inclusion (less than 12 hours) or pronounced lowering of hematocrit (greater than 15% of initial hematocrit) also did not profit from hemodilution. Clinical deterioration observed in eight hemodilution group patients (p less than 0.01) led to discontinuation of the study for ethical reasons.

Adolescent↗
PubMed1991

[Obstruction of pulmonary arteries. Contribution of the scanner and MRI. Apropos of 10 cases].

We present a retrospective study of ten patients presenting non specific clinical manifestations in whom the diagnosis of pulmonary embolism was documented by CT scan and/or MRI. Results of CT scan and/or MRI were compared to DSA bi-selective pulmonary angiography findings. In a large number of cases, CT scan and MRI allowed the detection of the obstruction within the right and left pulmonary arteries (RPA and LPA). Although these techniques did not permit the diagnosis of peripheral clots, pulmonary infarcts were usually depicted by these two procedures. CT scan and/or MRI could be performed as first-line investigations in case of atypical clinical symptoms because of their high relevance for proximal pulmonary artery obstruction, although these two non-invasive procedures cannot indicate the aetiology of the obstruction etiology.

Evaluation Studies as Topic↗
PubMed1990

Brain stem mechanism in ocular motor function.

The progress of clinical and experimental neuro-ophthalmology during the last two decades was reviewed. The ocular motor system in the brain stem was described firstly based on anatomical, neurophysiological and clinical evidences. Clinical syndromes in cerebrovascular brain stem impairments which present ocular motor dysfunction were analyzed briefly.

Animals↗
PubMed1990

[Therapeutic concept in asymptomatic carotid stenosis: surgical indications from the neurologic viewpoint in comparison with spontaneous course].

The annual risk of stroke from asymptomatic carotid stenosis is about 0.5-2.5%. After successful carotid endarterectomy (CEA) the risk of suffering a stroke amounts to about 2% per year. CEA therefore seems to impose an unnecessary risk upon the patient. However, a stenosis with more than 80% luminal narrowing, a rapidly progressing stenosis, and ulcers may increase the spontaneous risk and should be evaluated in randomized studies. The same applies to prophylactic CEA of asymptomatic stenosis before major cardiac or vascular surgery.

Carotid Stenosis↗
PubMed1990

[Perforation of a loop of the small intestine by a Kim-Ray Greenfield endocaval filter. Report of a case].

Kim-Ray filter complications are usually benign, such as angulation or slight migration. We report and compare with the literature one case of vena cava perforation associated with a small bowel lesion. The follow-up with regular abdominal plain X-rays allows detection of filter angulation, the first step before vena cava perforation. Cavography or CT scan depicts this perforation. Complete or partial surgical removal of the filter may be necessary.

Adult↗
PubMed1989

[Carotid endarterectomy. A justifiable risk for the prevention of ischemic infarct?].

Defining the position of carotid endarteriectomy (CEA) is difficult, since the average mortality and morbidity risk of this procedure--an estimated 10% or so overall in the USA--is apparently much higher than is achievable in highly specialized centers or is indicated by uncontrolled studies. No clear indication is recognizable for asymptomatic stenoses. Possible exceptions are rapidly progressing and high-grade stenoses. Prophylactic CEA within the framework of major surgical interventions increases the risk of perioperative stroke. In the event of transient ischemic attacks (TIA), carotid endarteriectomy is justifiable when cardiac sources of embolism, severe intracranial vascular stenoses and a predominantly cerebral microangiopathy have all been excluded, as also internistic and neurological disorders that increase the risks of surgery. In the acute insult stage, CEA increases mortality severalfold, and is therefore contraindicated.

Carotid Artery Diseases↗
PubMed1989

[Ulcero-mutilating acro-osteopathy in hereditary neuropathies. Differential diagnosis and pathogenesis].

Two patients, aged 51 and 70 years, had indolent ulcerations at the sole of the foot with destructive osteolysis in the bones of the feet, lesions characteristic of mutilating ulcerative acro-osteopathy. Patient 1, who had pes cavus, developed ulcerations on the balls of the feet along the second metatarsal bones, and patient 2 with pes equinovarus developed ulcers in the area of the calcaneus. Sock-like hypesthesia/hypalgesia from the toes to the ankles was present in both patients, and electrophysiological tests confirmed the presence of axonal sensory-motor neuropathy. Diabetes mellitus and alcohol abuse was excluded in both patient. Clinical findings, history and neurological disturbances in both patients identified the disease as hereditary sensory neuropathy (type I).

Aged↗