Biomedical subjects
Publications and source records attributed to E Varga.
The authors deal with the case of a 6-year old girl in whom thrombocytopenia developed with haemorrhagic symptoms as a rare complication of varicella. They give a short review about the reasons and the etiology of idiopathic thrombocytopenic purpura, and deal with the mechanism of thrombocytopenia caused by varicella.
Ninety-nine isotope, 4 CT and 10 MR examinations were carried out in 1990 to test urogenital disorders in infants and children. The procedures are described with sidelights on indication, difficulties of technical nature and comparison with internationally published reports. An examination strategy is devised, with estimation of its effectiveness in the follow-up and after-care.
A patient with intra-oral squamous cell carcinoma arising in an area of cyclosporin-induced gingival hyperplasia associated with a renal transplant is presented. This appears to be the first reported case of its kind. Subsequently, the patient developed a carcinoma of the lateral margin of the tongue, with metastasis to the deep cervical lymph nodes. The incidence and types of malignancy following conventional immunosuppressive and cyclosporin therapy are briefly reviewed. Long-term frequent follow-up of cyclosporin-treated patients is recommended to facilitate early diagnosis of such lesions.
Ultrasound examinations and stress radiographs of 61 patients with suspected ligamentar lesion of the ankle and knee joints were compared in order to clear, whether radiography could be replaced by sonography. In our experience, the opening of the joint gap can also be adequately demonstrated even without ionizing radiation and the results achieved by ultrasound were nearly as accurate as by X-rays. Being a rather simple, inexpensive and real time method, producing acceptable visual information and practicable on almost all preexisting equipments, sonography is advised for detecting of ligamentar lesions.
We prepared a tritiated chloromethyl ketone derivative of Tyr-D-Ala-Gly(Me)Phe-Gly-ol 3H-D-Ala-Gly-(Me)Phe-chloromethyl ketone, and studied its binding characteristics in rat brain membranes. A significant portion (about 70%) of the binding becomes wash-resistant after 60 min of incubation. The binding of the ligand is highly stereospecific and mu-opioid receptor selective. These characteristics of the ligand, together with its high specific radioactivity (57 Ci/mmol) makes it a good candidate for biochemical characterization and covalent labeling of mu opioid receptors.
C-6 derivatives--hydrazones, phenylhydrazones, dinitrophenylhydrazones, oximes and semicarbazones--of morphinane-6-ones were synthesized and their binding characteristics were studied on rat brain membranes. The dihydromorphinone and oxymorphone derivatives compete for the (3H)naloxone binding sites with high affinity, while the dihydrocodeinone and oxycodone derivatives are less potent. The affinity of the new compounds is decreased for the delta sites as compared to the parent ligands. The ligands bearing bulky substituents also bind with low affinity to the kappa sites. The modification decreased the Na(+)-index of compounds indicating their mixed agonist-antagonist character. The dihydromorphinone derivatives are all capable to block irreversibly the high affinity binding site of (3H)naloxone, whereas the dihydrocodeionone derivatives block irreversibly the low affinity site. A possible mechanism for the inhibition is suggested.
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Mixed connective tissue disease (MCTD) is a multisystem disorder with overlapping features of systemic lupus erythematosus, scleroderma and polymyositis and is differentiated from them by a high titre of antibody to ribonucleoprotein. Orofacial manifestations of MCTD include trigeminal neuralgia-like pain, neuropathy, features suggestive of Sjögren's syndrome and lymphadenopathy. The recent experience of two patients presenting with trigeminal neuropathy as an early manifestation of this disease is described. One of these patients presented with 'lichenoid' oral mucosal lesions as a further early manifestation of MCTD. This appears to be the first case with this presenting feature to be described in the literature.
A kappa-opioid receptor subtype was purified from a digitonin extract of frog brain membranes, using affinity chromatography. The affinity resin was prepared by coupling dynorphin (1-10) to AH Sepharose 4B. The purified receptor binds 4,750 pmol [3H]ethylketocyclazocine (EKC) per mg protein (5,600-fold purification over the membrane-bound receptor) with a Kd of 9.1 nM. The addition of cholesterol-phosphatidylethanolamine (2:1) enhanced 3.6-fold the binding activity of the purified material, which gives a purification very close to the theoretical. The purified receptor protein exhibits high affinity for kappa-selective ligands. The purified fraction shows one major band (65,000 Mr) in sodium dodecyl sulfate (SDS) gel electrophoresis.
The distribution and properties of frog brain kappa-opioid receptor subtypes differ not only from those of the guinea pig brain, but also from that of the rat brain. In guinea pig cerebellum the kappa 1 is the dominant receptor subtype, frog brain contains mainly the kappa 2 subtype, and the distribution of the rat brain subtypes is intermediate between the two others. In competition experiments it has been established that ethylketocyclazocine and N-cyclopropylmethyl-norazidomorphine, which are nonselective kappa-ligands, have relatively high affinities to frog brain membranes. The kappa 2 ligands (Met5)enkephalin-Arg6-Phe7 and etorphine also show high affinities to the frog brain. Kappa 1 binding sites measured in the presence of 5 microM/D-Ala2-Leu5/enkephalin represent 25-30% of [3H]ethylketocyclazocine binding in frog brain membranes. The kappa 2 subtype in frog brain resembles more to the mu subtype than the delta subtype of opioid receptors, but it differs from the mu subtype in displaying low affinity toward beta-endorphin and /D-Ala2-(Me)Phe4-Gly5-ol/enkephalin (DAGO). From our data it is evident that the opioid receptor subtypes are already present in the amphibian brain but the differences among them are less pronounced than in mammalian brain.
Mesenchymal renal tumors in F-344 newborn rats were induced by a single dose of dimethylnitrosamine. The induced tumors were successfully transplanted into adult rats under the renal capsule. Neither the primary nor the transplanted neoplasms from various generations of grafts changed their morphological features during the tumor passage, having the same cellularity with high mitotic activity and the tendency to invade the host kidney rapidly. On the basis of lectin histochemistry and immunohistology, the tumor proved to be a mesenchymal neoplasm without any obvious capacity of the proliferating cells to differentiate into any well-known organoid element normally found in mature renal parenchyma. However, the proliferating neoplastic cells were found to have a strong vimentin positivity with desmin expression. Ultrastructurally, myofilaments with attachment bodies characteristic of smooth muscle cells were generally present in various amounts in many tumor cells. In addition, on the basis of the physiological data and on kidney/tumor renin activity obtained, it is interesting to note that the tumor-graft-invaded kidneys retained their enzyme activity, despite the obvious loss of renal tissue including glomeruli. However, the immunohistochemical findings with anti-renin antibody have clearly shown that this is not due to a renin-producing tumor but rather to the surviving (probably) non-neoplastic arterioles retaining the capacity to produce renin. Although these arterioles have mostly been found next to necrotic areas, commonly occurring in dimethylnitrosamine-induced transplantable renal tumors, the question of a possible physiological role of renin in tumor necrosis or in angiogenesis has remained open.
Using a probe derived from the human 5-HT1A receptor gene (G-21), a strongly hybridizable clone was identified from a rat genomic DNA library. This clone (G21Y2) had an overall deduced amino acid sequence that was 88% homologous with that of the human 5-HT1A receptor. There was only an 18% and 19% amino acid homology with the rat 5-HT1C and 5-HT2 receptors, respectively. The G21Y2 appears to be an excellent candidate for the rat 5-HT1A receptor gene. As this manuscript was being prepared a report by Albert et al. (13) was published in which a probe to the hamster beta 2-adrenergic receptor was used to identify a rat genomic (Clone D) that demonstrated a sequence that was similar to G21Y2.
Opioid receptors of the frog (Rana esculenta) brain are characterized mainly by their relatively high ethylketocyclazocine (EKC) binding properties and by their low affinity to mu and delta ligands when D-Ala2-(Me)Phe4-Gly5-ol enkephalin (DAGO) and D-Ala2-Leu5-enkephalin (DALE) is used. In competition experiments it has been established that EKC and N-cyclopropylmethyl-norazidomorphine (CAM), which are non-selective kappa-ligands, have relatively high affinity to frog brain as well as the kappa 2 (which is DALE sensitive subpopulation of the kappa receptor) ligands etorphine and Metenkephalin-Arg6-Phe7 (1.). The kappa 2 subtype in frog brain resembles more to the mu subtype than to the delta subtype of opioid receptors, but it differs from the mu subtype in displaying low affinity toward beta-endorphin and DAGO.
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Authors studied a frequent injury of the finger joints. The anatomy, the mechanism of the injuries, the diagnostic possibilities of the lamina fibrocartilaginea ("palmar plate") and of the palmar ligaments of the joints are described. In the diagnosis a special significance is attached to the stressed and tangential X-ray pictures. They take the part of the conservative treatment of the injury. In cases of dislocations, that cannot be reduced, of open "palmar plate" injuries and of major hyperextension and dislocations of the broken bone scale, operative treatment is thought necessary. In the treatment of the injuries of the "palmar plate" of the PIP joint they use the so called rein method, that keeps the palmar cartilaginous joint capsule, torn at the injury, on its original place, it enables however the active joint movements, the gymnastics and hinders this way the development of the joint contracture.
Basolateral interstitial spaces (BLIS) of the murine macula densa (MD) are dilated in kidneys fixed either by in vivo glutaraldehyde perfusion or snap freezing-freeze substitution, suggesting that macula densa intercellular spaces may be normally dilated in the functioning nephron. BLIS are also dilated in MD with luminal obstruction with "hyaline" cylinder. This finding might indicate a glomerulo-macular fluid and solute streaming, having an impact on the tubuloglomerular feedback mechanism.