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Biomedical subjects

M Kessler

Publications and source records attributed to M Kessler.

At least 163 records · Page 9Linked to original sources
PubMed1995

Stable maintenance of glutamate receptors and other synaptic components in long-term hippocampal slices.

Cultured hippocampal slices retain many in vivo features with regard to circuitry, synaptic plasticity, and pathological responsiveness, while remaining accessible to a variety of experimental manipulations. The present study used ligand binding, immunostaining, and in situ hybridization assays to determine the stability of AMPA- and NMDA-type glutamate receptors and other synaptic proteins in slice cultures obtained from 11 day postnatal rats and maintained in culture for at least 4 weeks. Binding of the glutamate receptor ligands [3H]AMPA and [3H]MK-801 exhibited a small and transient decrease immediately after slice preparation, but the binding levels recovered by culture day (CD) 5-10 and remained stable for at least 30 days in culture. Autoradiographic analyses with both ligands revealed labeling of dendritic fields similar to adult tissue. In addition, slices at CD 10-20 expressed a low to high affinity [3H]AMPA binding ratio that was comparable with that in the adult hippocampus (10:1). AMPA receptor subunits GluR1 and GluR2/3 and an NMDA receptor subunit (NMDAR1) exhibited similar postcutting decreases as that exhibited by the ligand binding levels, followed by stable recovery. The GluR4 AMPA receptor subunit was not evident during the first 10 CDs but slowly reached detectable levels thereafter in some slices. Immunocytochemistry and in situ hybridization techniques revealed adult-like labeling of subunit proteins in dendritic processes and their mRNAs in neuronal cell body layers. Long-term maintenance was evident for other synapse-related proteins, including synaptophysin, neural cell adhesion molecule isoforms (NCAMs), and an AMPA receptor related antigen (GR53), as well as for certain structural and cytoskeletal components (e.g., myelin basic protein, spectrin, microtubule-associated proteins). In summary, following an initial and brief depression, many synaptic components were expressed at steady-state levels in long-term hippocampal slices, thus allowing the use of such a culture system for investigations into mechanisms of brain synapses.

Amino Acid Sequence↗
PubMed1995

[Ki-1 positive non-Hodgkin's lymphoma disclosed by mucocutaneous ulcerations and glomerulonephritis].

Malignant lymphoma particularly of T phenotype can be associated with specific or non specific cutaneous lesions. These cutaneous manifestations can occur at the onset of the disease being sometimes the revealing sign or they can appear during the course of the lymphoreticular malignancies. Glomerulonephritis was also described in lymphoma. Ki-1 positive large cell lymphoma was recently identified. A new case is reported with lymphadenopathy and intestinal localisation revealed by cutaneous and mucosal ulcerations principally in the mouth and a focal segmental glomerulonephritis with endo- and extracapillary proliferation. The absence of lymphoma in cutaneous and renal lesions and the clinical presentation support the hypothesis of paraneoplastic manifestations, may be related to a vasculitis.

Glomerulonephritis↗
PubMed1995

Epstein-Barr virus lymphoproliferative disease of donor origin after kidney transplantation: a case report.

A case of an Epstein-Barr virus (EBV)-associated B lymphoproliferative disorder presented as a renal transplant obstruction is reported. The diagnosis was made from histology, immunohistochemistry, and EBV expression studies. Cytogenetic analysis showed the tumor to be of donor origin and revealed chromosomal translocation 46, XY, inv (1)(p35; q41), involving the EBV insertion site 1(1p35) and transforming growth factor beta 2(1q41) loci.

Aged↗
PubMed1995

Effect of thiocyanate on AMPA receptor mediated responses in excised patches and hippocampal slices.

The binding affinity of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors for [3H]AMPA is increased 10-30-fold by the chaotropic anion thiocyanate. The present experiments tested if thiocyanate alters AMPA receptor mediated current fluxes and if any such effects are reflected in the waveform of synaptic responses. Currents were measured after a step application of glutamate or AMPA to patches excised from pyramidal cells of hippocampal slice cultures. Application of 1 mM AMPA produced responses with an average peak amplitude of 86 pA at -50 mV and a 10-90% rise time of 1.7 +/- 0.1 ms; the responses desensitized to a steady-state level below 10% of the peak current with a time constant of 11.1 +/- 0.7 ms. Glutamate in presence of D-amino-phosphonopentanoate produced similar responses which were inhibited by 6-cyano-7-nitro-quinoxaline-dione and enhanced by aniracetam or cyclothiazide and thus are characteristic for AMPA receptors. Thiocyanate accelerated the decay of AMPA responses two-fold and reduced the peak current by 30-50% with an EC50 of 3.2 mM which is comparable to its EC50 for enhancing binding. Effects on the desensitization of glutamate induced responses were much smaller and only evident at the highest thiocyanate concentration; no effect was seen on response amplitude. Binding and physiological effects can be adequately explained by assuming that thiocyanate enhances conversion from the sensitive to the desensitized state of the receptor and reduces ligand dissociation from the desensitized state. Synaptic responses were measured in disinhibited hippocampal slices. Perfusion with 20 mM sodium thiocyanate increased the slope of the field excitatory postsynaptic potential by 44.9 +/- 4.2% and reduced its decay time by 10.4 +/- 4.3%. The former effect appears to result at least in part from an increase in transmitter release since it was accompanied by a decrease in paired-pulse facilitation and was reduced in magnitude after enhancing transmitter release. The decrease in the decay time constant points to an effect of thiocyanate on AMPA receptors in situ which is similar to that seen in excised patches. These results demonstrate that an increase in binding affinity may be indicative of reduced rather than enhanced current flow through AMPA receptors. In addition, the results provide further evidence that the kinetics of the AMPA receptor channel contribute significantly to at least the decay phase of fast excitatory synaptic responses.

Animals↗
PubMed1995

Erythropoietin and erythropoiesis in renal transplantation.

This report reviews the features of erythropoietin (Epo) production after renal transplantation. Successful kidney transplantation leads to the correction of renal anaemia over an 8-10 week period. An early ineffective peak of serum Epo may occur when there is delayed graft function. A late peak follows the decrease in serum creatinine and this is associated with a rise in haemoglobin. Serum Epo returns to normal when the haematocrit reaches 32%. Acute early rejection causes a striking reduction in serum Epo and reticulocytosis. In some patients the haematocrit continues to increase after complete correction of anaemia, resulting in post-transplant erythrocytosis (PTE). PTE generally appears to be an idiopathic erythrocytosis independent of Epo secretion. A greater Epo sensitivity of erythroid progenitors has been suggested. Theophylline and angiotensin converting enzyme inhibitors, which attenuate Epo production, can be used to treat PTE. The second part of this report describes the possible impact of human recombinant Epo (rHuEpo) on renal transplantation. The avoidance of blood transfusion with rHuEpo should eliminate the initiation of anti-HLA sensitization in uraemic patients without previous pregnancy and prior allograft. In some but not all presensitized patients transfusion withdrawal may reduce the sensitization level. There is currently no evidence that the reversing of anaemia by rHuEpo in kidney recipients impairs early graft function. Our results suggest that treatment with rHuEpo prior to transplantation may prevent the appearance of PTE. rHuEPO will reverse anaemia in patients with a failing graft and severe anaemia with little risk of accelerating graft failure and adverse events.

Anemia↗
PubMed1995

Ginger-Sweet.

Explore the source record for details and available documents.

Adult↗
PubMed1995

Magnetic resonance imaging may be an asset to diagnose and classify fluoroquinolone-associated Achilles tendinitis.

The aim of this study was to document the accuracy of magnetic resonance imaging (MRI) during fluoroquinolone-associated Achilles tendinitis. Fourteen Achilles tendons were examined by MRI (T1 and T2 or T2*-weighted sequences) in nine patients with typical tendinopathy (13 cases of tendinitis and 1 rupture) during fluoroquinolone therapy. Tendinous involvement was classified according to the prominence of intra- or peritendinous changes. The most typical feature was the presence of intratendinous changes, longitudinal or transversal, detected on T1 or T2-weighted sequences. Peritendinitis was most visible in two cases and nodular involvement in three cases. It was concluded that MRI appears a helpful and accurate method in identifying and classifying such iatrogenic tendinitis. In addition, MRI indicates orthopedic management when detecting risk of rupture.

Achilles Tendon↗
PubMed1995

Serum secretory IgA and IgM and free secretory component in IgA nephropathy.

IgA nephropathy (IgAN) is characterized by the presence of IgA and C3 deposits in the mesangium. Mesangial IgA is mostly dimeric IgA1 with a J chain, lacking a secretory component. In view of the recent demonstration of elevated serum levels of secretory component and secretory IgA in liver disease and HIV infection associated with hyper-IgA, we measured the serum secretory component in 50 IgAN patients and 45 controls. Free secretory component and secretory IgA and IgM levels were determined by enzyme-linked immunosorbent assay. Normal or low levels were found patients. These data support previous work suggesting that in IgAN circulating and probably mesangial IgA do not originate from the epithelial compartment of the mucosal immunoglobulins as it is the case in other hyper-IgA diseases.

Adolescent↗
PubMed1995

[Imaging methods in diagnosis and differential diagnosis of breast cancer].

The diagnosis of breast cancer is primarily based on X-ray mammography. Under optimal conditions, a sensitivity of approximately 90% can be achieved. When strict criteria of indication are observed for the additional use of ultrasound or contrast-enhanced MRI, the sensitivity can be increased to about 98%. In addition, the differential diagnosis between benign and malignant lesions can be improved and the rate of biopsies due to false-positive mammograms can be reduced. However, further investigation with ultrasound or MRI of dense or mastopathic breasts that are clinically asymptomatic is not indicated, since it reduces specificity without significant gain of sensitivity.

Breast↗
PubMed1995

Serum anti-dextran antibodies in IgA nephropathy.

Abnormally high humoral responses have been described in IgA nephropathy (IgAN), towards antigens commonly involved in infectious events or food intolerance. Here we report a comparative analysis of humoral responses to a common environmental antigen, dextran B 512, present both in nonpathogenic microorganisms and normal diet. Dextran-specific IgG, IgA and IgM were assayed using an ELISA method in serum samples from 121 patients with IgAN, 40 controls and 32 patients with biopsy-proven renal diseases different from IgAN. Among the latter, 17 were transplant recipients. Anti-dextran IgG antibodies were found significantly (p < 0.05) more frequently and at higher levels in IgAN patients than in patients with other renal diseases. Anti-dextran IgA were at significantly (p < 0.05) higher levels in IgAN patients than in controls or untransplanted NIgAN patients. However, similarly elevated levels of anti-dextran IgA were found in IgAN patients and transplanted patients with other renal diseases. These data confirm that IgA and IgG responses towards common antigens are elevated in IgAN, possibly as a consequence of the pathogenesis of this disease rather than because of renal impairment. Moreover, since the same degree of dysregulation was noted in the control group of transplanted patients whose initial diagnosis was not IgAN, these data favour the hypothesis of a global dysregulation of the IgA system in IgAN, yielding enhanced humoral immune responses to possible pathogens and diet antigens.

Adult↗
PubMed1995

[Mast cell tumors in dogs--diagnosis and therapy of a malignant skin tumor].

The high prevalence of mast cell tumors in dogs and their variable presentation make this neoplasia a diagnostic and therapeutic challenge for the small animal practitioner. Classification of the tumor according to histologic grade and clinical stage of the disease is important for therapy and prognosis. Surgical excision and chemotherapy are discussed for individual tumor grades and stages.

Animals↗