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Biomedical subjects

M Mohr

Publications and source records attributed to M Mohr.

At least 73 records · Page 4Linked to original sources
PubMed1994

Neurobehavioral changes following bilateral infarct in the caudate nuclei: a case report with pathological analysis.

A patient presenting with loss of psychic self activation (LPSA) was studied clinically and at autopsy. Clinically, the patient showed changes that can be ascribed to the interruption of frontal-subcortical circuits. Pathological analysis revealed bilateral lesions of the caudate nuclei. This case extends others based on radiological findings and confirms the importance of the caudate nuclei in behavioral functions.

Aged↗
PubMed1994

Magnetic resonance imaging of antibody-mediated demyelinating experimental allergic encephalomyelitis.

Two models of demyelinating experimental allergic encephalomyelitis (EAE) were studied on Lewis rats in whom the disease was induced by injections of either (i) lentil-lectin binding myelin glycoproteins plus myelin basic protein (MBP)-specific T cells (36 rats), or (ii) myelin/oligodendrocyte glycoprotein-specific monoclonal antibody plus MBP-specific T cells (16 rats). In our 24 control rats, 20 received MBP-specific T cells only, and four received myelin glycoproteins plus purified protein derivative-specific T cells. The extent of the resulting blood-brain barrier (BBB) permeability, vasogenic oedema and/or demyelination was assessed in vivo using magnetic resonance imaging (MRI) techniques. The results show that in both demyelinating EAE models the disease appeared more quickly, progressed very rapidly and was more severe than when induced with a similar number of MBP-specific T cells alone. Almost all animals developed hyperacute EAE, with a very high mortality rate. MRI showed a very intense BBB breakdown and vasogenic oedema in all the normally 'leaky' areas of the central nervous system, and focal lesions corresponding to plaque formation in the brain stem or spinal cord near the 'leaky' areas. During the 40-day observation period, the rare survivors of this hyperacute form of EAE presented a chronic form of EAE with serious sequelae. Our results demonstrate that the synergistic effect observed between MBP-specific T cells and antibodies to myelin glycoproteins, especially to myelin/oligodendrocyte glycoprotein, does not only induce demyelinating lesions and chronic clinical signs, but is further responsible, via the normally 'leaky areas', for the fatal increase of the BBB breakdown and vasogenic oedema of which there are ample acute clinical signs.

Animals↗
PubMed1994

[Cervical epidural infusion of morphine and bupivacaine in severe erythromelalgia].

A 13 year old boy was admitted suffering from severe burning pain in both hands and distal forearms of two months duration. The skin in the affected areas was red and warm and was cooled by the boy with ice for alleviation of pain. Laboratory tests revealed no abnormalities. The diagnosis of primary erythromelalgia was made on the basis of the history and physical examination. At the age of nine months the boy had undergone surgery for hexadactyly of the right hand. In addition, the boy had complained of transient burning sensations in both feet several months prior to admission. Revision of the old scar at the beginning of the hand symptoms had been without effect. Initial analgesic attempts with oral paracetamol, acetylsalicylic acid, tramadol and intravenous morphine also had had no effect. Carbamazepine, methysergide and immunoglobulins led to no improvement. Symptomatic relief was achieved only by cooling the distal parts of both arms with water. This caused oedema and maceration of the skin after several days. The placement of a cervical epidural catheter and the infusion of morphine and bupivacaine led to a pronounced pain relief within hours and the forearms could be removed from the cool water. The epidural infusion was continued for two weeks with slowly decreasing amounts of morphine and bupivacaine. During this time there was a marked improvement in both oedema and erythema. No complications resulted from the cervical epidural infusion. Because of the long-standing immobilisation and water exposure the boy had to undergo intensive training of the upper extremities during the following weeks to regain full muscular function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

The role of Mycobacterium tuberculosis in experimental allergic encephalomyelitis.

Various detergents used in preparative membrane protein chemistry were added to a complete Freund's adjuvant/water emulsion in order to increase the solubility and/or immunologic availability of the Mycobacterium tuberculosis membrane and to explain its role in blood-brain barrier (BBB) permeability. Magnetic resonance imaging was used for in vivo determination of the BBB breakdown and cerebral edema. The results showed that with 1% 10 tridecyl ether, which increases emulsion stability, abundant BBB breakdown and cerebral edema were observed, similar to those encountered in experimental allergic encephalomyelitis (EAE). We suggest that the immunologic response triggered off by M. tuberculosis largely contributes to the BBB permeability changes observed during EAE, probably by an action on the endothelial cells of the cerebral blood vessels.

Animals↗
PubMed1994

HLA-DPB1 typing by PCR-SSO reverse dot blot hybridization after group-specific amplification.

BACKGROUND: The allelic diversity of HLA-DPB1 antigens can be determined at the DNA level after PCR amplification. The pattern of polymorphism at the DPB1 locus makes it difficult to unambiguously assign all genotypes in a typing system using one single pair of generic primers. MATERIALS AND METHODS: We apply here a simple technique based on the reverse dot blot analysis to the typing of HLA-DPB1 alleles. In order to increase its resolution, a group-specific amplification based on sequence variations of the polymorphic region F was used subdividing the HLA-DPB1 alleles in 2 nonoverlapping families. A separate analysis was then performed within each group of alleles. RESULTS: Using these 2 primer pairs, 21 group 1 and 30 group 2 alleles were separately amplified. From 1,378 possible allele combinations for DPB1*0101-5301 only 33 gave ambiguous typing results compared to 61 using a single pair of generic primers. CONCLUSIONS: This procedure provides a rapid and simple HLA-DPB1 genotyping. Especially in heterozygotes the hybridization patterns were easier to interpret. The utilization of group-specific amplification substantially reduced ambiguous typing results.

Alleles↗
PubMed1993

Pseudomonas aeruginosa cytotoxin-binding protein in rabbit erythrocyte membranes. An oligomer of 28 kDa with similarity to transmembrane channel proteins.

Rabbit erythrocyte membrane glycosylated 28-kDa protein was investigated in the membrane-bound as well as in the soluble state on an example of a Pseudomonas aeruginosa cytotoxin-binding component. When membranes were treated with trypsin/N-glycosidase F, a 13.5-kDa-binding active peptide residue is obtained as revealed by a ligand-blot technique after separation by SDS/PAGE under reducing conditions and electrophoretic transfer to nitrocellulose. Target-size analysis of intact membranes by radiation inactivation using 2-450 kGy gave a value of 29, 40 and 60 kDa for the binding-protein structure. This suggests that the native form of the binding peptide is associated as an oligomer. As seen in ligand-blot technique, 125I-cytotoxin binds with high affinity to water-channel integral protein CHIP28 from human erythrocyte membranes. The 20 N-terminal amino acids of the deglycosylated rabbit cytotoxin-binding protein show high similarity to transmembrane channel-like proteins.

Amino Acid Sequence↗
PubMed1993

Interstitial lung disease--an underdiagnosed side effect of chlorambucil?

A case of recurrent interstitial pneumonia following re-exposure to chlorambucil therapy for chronic lymphocytic leukemia is presented. Chlorambucil is a rare cause of pulmonary disease. The onset of symptoms may occur after only some weeks or after up to several years with no dose-response relationship. Therapy involves the discontinuation of the offending drug and the administration of steroids. The prognosis is poor, with a mortality greater than 50%.

Chlorambucil↗
PubMed1993

Blood-brain barrier breakdown in MBP-specific T cell induced experimental allergic encephalomyelitis. A quantitative in vivo MRI study.

Blood--brain barrier permeability in myelin basic protein (MBP)-specific T cell induced experimental allergic encephalomyelitis (EAE) was studied by magnetic resonance imaging (MRI) in Lewis rats. Myelin basic protein-specific T cells of different specificity and/or purified protein derivative (PPD)-specific T cells were used. During the course of EAE, the volume of the lesions and the T1 and T2 relaxation times were recorded and evaluated with respect to the clinical signs. The results showed that the severity of abnormalities seen on MRI, corresponding to the blood--brain barrier breakdown and cerebral oedema depended on the following two factors: (i) the specificity of the MBP-specific T cells used; (ii) the number of MBP-specific T cells transferred. It was also shown that the more specific the cells were, the less severe the cerebral blood--brain barrier rupture. Moreover, the blood--brain barrier breakdown increased when the number of cells increased. Our results demonstrated that a synergy exists between MBP and PPD-specific T cells which seems to result in an increase in central nervous system inflammation. This helps to explain the role of Mycobacterium tuberculosis in the induction of EAE.

Animals↗
PubMed1993

A new peroxisomal disease with impaired phytanic and pipecolic acid oxidation.

Phytanic acid (PA) accumulates in patients with adult Refsum disease (ARD) and with peroxisomal disorders. In three related patients with ARD, PA levels were moderately increased in plasma, whereas phytanic oxidation was severely deficient in the fibroblasts. Two of these patients had a significant increase of pipecolic acid in plasma, a finding not reported in ARD, and a fourth related patient, a brother, died at age 17 from a progressive neurologic disorder with unusual clinical and neuropathologic (a spongy degeneration of the white matter) abnormalities for ARD. The first step of L-pipecolic acid degradation occurs in peroxisome. In these patients, the accumulation of PA could have resulted from an impaired capacity to degrade pristanic acid rather than PA. The activity of pristanic oxidase, measured in fibroblasts, was normal, as were two other peroxisomal enzymes, lignoceric acid oxidase and dihydroxyacetone phosphate transferase. Since both mitochondria and peroxisomes are involved in PA alpha-oxidation, we propose that these four related patients presented various phenotypical variants of a novel peroxisomal disease with impairment of PA and pipecolic acid oxidation.

Adolescent↗
PubMed1992

Familial motor neuron disease with Lewy body-like inclusions in the substantia nigra, the subthalamic nucleus, and the globus pallidus.

In a familial case of motor neuron disease (MND), 2 unusual features were noted in the necropsy. The first was a pallidoluysonigral degeneration, observed in only 4 other cases of MND and which was here asymptomatic. The second was the presence in degenerated spinal cord anterior horns and in degenerated basal ganglia of neuronal Lewy body-like inclusions stained by antibodies against ubiquitin.

Genes, Dominant↗
PubMed1992

The morbidity associated with lost or irretrievable resected meniscal fragments.

Between January 1984 and April 1989 pieces of already-separated meniscus were lost in the knees of 23 patients as a complication of knee arthroscopy. These patients were asked to complete a questionnaire with regard to their postoperative problems. Despite the fact that some of these pieces were up to 4 cm in length, only 3 patients were dissatisfied with the results and had to undergo arthroscopy once again. When compared with the total number of arthroscopies (2,927) performed in the same period, we found no significant differences in patient ages, accompanying injury patterns, nor the time they were unable to work. These surprisingly excellent results demonstrate that a lost piece of meniscus in the knee space does not always indicate immediate repeat arthroscopy. In most cases, this loose piece probably will adhere to a place inside the knee where it will no longer be a mechanical hindrance.

Arthroscopy↗
PubMed1992

Varicella-zoster virus encephalitis in acquired immunodeficiency syndrome: report of four cases.

Four patients with acquired immunodeficiency syndrome, a 27-year-old female intravenous drug abuser and three males (two drug addicts aged 27 and 33 years and a 40-year-old homosexual) presented with a rapidly progressive encephalopathy. Two had generalized varicella-zoster virus skin infection, one had had a regressive thoracic zoster rash 7 months previously and one had no history of cutaneous eruption. Neuropathological examination revealed, in each case, multifocal necrotic changes with numerous, intranuclear Cowdry type A inclusion bodies in glial cells, endothelial cells, macrophages and neurons, within and around the lesions. These inclusion bodies were stained positively for varicella-zoster virus by immunocytochemistry and contained herpes virus nucleocapsids by electron microscopy. Molecular biology using the polymerase-chain-reaction method demonstrated viral genome. In one case, zoster-induced non-inflammatory vasculopathy involved medium sized leptomeningeal vessels and was associated with circumscribed areas of cortico-subcortical infarction. In another case, varicella-zoster virus encephalitis was associated with human immunodeficiency virus encephalitis and a secondary cerebral lymphoma. Multinucleated giant cells expressing human immunodeficiency virus proteins in their cytoplasm, were found in the lymphomatous deposits and in the varicella-zoster virus necrotic lesions. In these latter lesions, Cowdry type A inclusion bodies could be seen in the nuclei of some multinucleated giant cells confirming previous observations of MGCs co-infected by HIV and CMV, and supporting the hypothesis that DNA viruses interact with HIV, thus increasing its effect.

Acquired Immunodeficiency Syndrome↗
PubMed1992

[Sciatic radiculalgia with muscular hypertrophy].

A 52-year-old male developed hypertrophy of the right calf after several bouts of right lumbar pain with sciatica. Electromyography disclosed evidence of demyelination in the territories of the right S1 and S2 roots. Microscopic studies showed both atrophic muscle fibers scattered among fibers of normal caliber and a large number of hypertrophic fibers. Post-sciatica hypertrophy of the calf is a true muscle hypertrophy with muscle weakness. Electromyography may show unusual tracings with repeated complex bursts or continuous activity of motor units. Muscle enzyme levels may be elevated. The size of hypertrophied fibers varies across cases. The cause of the muscle fiber hypertrophy may be either stretching due to the action of antagonists or unusual electrical activity.

Electromyography↗
PubMed1991

Fulminating multiple sclerosis-like leukoencephalopathy revealing human immunodeficiency virus infection.

A 66-year-old French homosexual man and a 42-year-old Brazilian man with no known risk factors for HIV infection developed headaches, asthenia, and neurologic episodes of abrupt onset. CT showed multiple hypodense, nonenhancing lesions. Serology for HIV was positive. They died respectively 2 months and 1 month after onset of the illnesses. Autopsy in both cases showed multiple, well-demarcated, demyelinating foci in the white matter of the cerebral hemispheres, brainstem, and cerebellum with histologic features characteristic of recent plaques of multiple sclerosis. There were no multinucleated giant cells or microglial nodules. Immunostaining for HIV was negative. Although a random coincidence of MS and HIV infection cannot be ruled out, the close temporal relationship between the 2 disorders suggests a possible etiologic association.

Adult↗
PubMed1991

[Therapy strategies for Still's syndrome of adults (AOSD)].

The differential diagnosis of seronegative polyarthritides are manyfold and can cause problems even for the routine rheumatologist. Together with the symptom "fever of unknown origin" an intensive diagnostic workup is often unavoidable. Five patients with this symptom combination are discussed who also had different typical manifestations of the adult onset Still's disease (AOSD).

Adolescent↗
PubMed1991

New approaches towards automated oligoribonucleotide synthesis.

Several protecting group combinations have been investigated to achieve an automated oligoribonucleotide synthesis on a solid support. The use of 2'-O-tert-butyldimethylsilyl-5'-O-monomethoxytrityl-ribonucleoside -3'-(p-nitrophenylethyl, N,N-diethyl)-phosphoramidites in conjunction with beta-eliminating blocking groups at the aglycone gave satisfactory results. An inverse protecting group strategy based upon analogously substituted 5'-O-2-dansylethoxycarbonyl-2'-O-4- methoxytetrahydropyran-4-yl-phosphoramidites can be regarded as another promising approach.

Base Sequence↗
PubMed1990

Cardiogenic oscillations of He and SF6 in expired gas in dogs.

Quantitative analysis of cardiogenic oscillations of He and SF6 during airway and venous loading demonstrated that both VA/Q and VA/VA inequalities were involved in the lung gas inhomogeneity producing cardiac oscillations in the expirogram. Both inequalities were coupled in such a manner that low VA/Q units had high VA/VA. The oscillations were modified in conducting airways where SF6 oscillations were attenuated more than He oscillations, probably by laminar Taylor dispersion.

Animals↗