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Biomedical subjects

M Kelemen

Publications and source records attributed to M Kelemen.

13 recordsLinked to original sources
PubMed2000

Pathological and immunological study of an in ovo complex vaccine against infectious bursal disease.

The appearance of very virulent strains of infectious bursal disease (IBD) virus at the end of the 1980s made it necessary to develop more effective immunization procedures. To facilitate this, the immunogenicity and the immunosuppressive effect of a mild (G-87), an intermediate (LIBD) and an intermediate-plus (IBDV 2512) IBDV strain were tested after the in ovo inoculation of 18-day-old SPF and broiler chicken embryos. It was established that no noteworthy difference existed between the immunized and the control embryos in hatching rate and hatching weight. The higher the virulence of the vaccine virus strain, the more severe damage it caused to the lymphocytes of the bursa of Fabricius. In SPF chickens, the haemagglutination inhibition (HI) titres induced by a Newcastle disease (ND) vaccine administered at day old decreased in inverse ratio to the virulence of the IBD vaccine strain, while in broiler chickens this was not observed. Despite the decrease of the HI titre, the level of protection did not decline, or did so only after the use of the 'hot' strain. SPF chickens immunized in ovo with a complex vaccine prepared from strain IBDV 2512 and IBD antibody showed the same protection against Newcastle disease as the broilers. In broiler chicken embryos immunized in ovo, only strain IBDV 2512 induced antibody production, and such chickens were protected against IBD at 3 weeks of age. The complex vaccine administered in ovo has been used successfully at farm hatcheries as well.

Animals↗
PubMed1991

[Diagnostic significance of clinical symptoms versus ultrasonography in appendicitis. A prospective study].

The aim of the presented study was to find what importance ultrasonography has in the diagnosis of acute appendicitis compared to clinical findings and on the surgeon's decision regarding to laparotomy. 111 patients entering the emergency station with suspected appendicitis were evaluated in a prospective clinical study. Surgeon and radiologist had to commit themselves to the diagnosis, afterwards signs were discussed. Clinical accuracy over all was 89%. Pain migration and peritonitis signs corresponded significantly with appendicitis (p less than 0.0001). The appendix was well seen in sonographic examination in 32% (accuracy 80%), in 27% was doubtful (accuracy 70%), and in 41% the appendix could not be demonstrated. Diameter of a normal appendix was 8 mm compared to 12 mm for an inflamed appendix (p less than 0.05). Rates negative laparotomies decreased from 16% to 12.7%. The surgeon was not influenced by sonography in 75%. In 12% ultrasonography decided for laparotomy and in 4.5% sonography prevented operation. We conclude from our results, that sonography reduces the negative laparotomy rate. Ultrasonography is especially useful in doubtful clinical pictures. Clinical findings and experience remain of major importance in appendicitis-diagnosis.

Adolescent↗
PubMed1991

[Does sonography help in the diagnosis of appendicitis?].

The aim of the presented study was to find whether improvement has ultrasonography in the diagnosis of acute appendicitis and on surgeon's decision referring to laparotomy. 111 patients entering into the emergency station with suspected appendicitis were evaluated in a prospective clinical study. Surgeon and radiologist had to commit themselves to the diagnosis, afterwards signs were discussed. In 32% the appendix was well seen (accuracy 80%), in 27% sonographic examination was doubtful (accuracy 70%) and in 41% the appendix could not be demonstrated. Diameter of normal appendix was 8 mm compared to inflamed appendix with 12 mm (p less than 0.05). The negative laparotomy decreased from 16% to 12.7%. Surgeon was not influenced by sonography in 75%. In 12% ultrasonography decided for laparotomy and in 4.5% sonography prevented operation. We conclude from our results, that sonography reduces negative laparotomy rate. Especially ultrasonography is useful in doubtful clinical pictures.

Abdomen, Acute↗
PubMed1987

Affinity labeling of delta-opiate receptors using [D-Ala2,Leu5,Cys6]enkephalin. Covalent attachment via thiol-disulfide exchange.

[D-Ala2,Leu5,Cys6]Enkephalin (DALCE) is a synthetic enkephalin analog which contains a sulfhydryl group. DALCE binds with high affinity to delta-receptors, with moderate affinity to mu-receptors, and with negligible affinity to kappa-receptors. Pretreatment of rat brain membranes with DALCE resulted in concentration-dependent loss of delta-binding sites. Using 2 nM [3H][D-Pen2,D-Pen5]enkephalin (where Pen represents penicillamine) to label delta-sites, 50% loss of sites occurred at about 3 microM DALCE. Loss of sites was not reversed by subsequent incubation in buffer containing 250 mM NaCl and 100 microM guanyl-5'-yl imidodiphosphate (Gpp(NH)p), conditions which cause dissociation of opiate agonists. By contrast, the enkephalin analogs [D-Ala2,D-Leu5]enkephalin, [D-Ser2,Leu5,Thr6]enkephalin, [D-Pen2,D-Pen5]enkephalin, and [D-Ala2,D-Leu5,Lys6]enkephalin were readily dissociated by NaCl and Gpp(NH)p, producing negligible loss at 3 microM. This suggests that DALCE binds covalently to the receptors. Pretreatment of membranes with the reducing agents dithiothreitol and beta-mercaptoethanol had no effect on opiate binding. Thus, loss of sites required both specific recognition by opiate receptors and a thiol group. The irreversible effect of DALCE was completely selective for delta-receptors. Pretreatment with DALCE had no effect on binding of ligands to mu- or kappa-receptors. The effect of DALCE on delta-binding was: 1) markedly attenuated by inclusion of dithiothreitol in the preincubation buffer, 2) partially reversed by subsequent incubation with dithiothreitol, 3) slightly enhanced when converted to the disulfide-linked dimer, and 4) prevented by blocking the DALCE sulfhydryl group with N-ethylmaleimide or iodoacetamide. These results indicate that DALCE binds covalently to delta-receptors by forming a disulfide bond with a sulfhydryl group in the binding site. The mechanism may involve a thiol-disulfide exchange reaction.

Animals↗
PubMed1986

Characterization of D-Ala2,Leu5,Cys6-enkephalin: a novel synthetic opioid peptide with slowed dissociation from delta receptors.

D-Ala2,Leu5,Cys6-enkephalin (DALCE) is a synthetic enkephalin analog which contains a reduced sulfhydryl group. It exhibited moderate delta selectivity (mu/delta IC50 ratio 13), but was not as selective as the disulfide-containing peptide, D-Pen2,5-enkephalin (DPDPE) (mu/delta ratio 1121). However, unlike other delta-selective peptides, DALCE exhibited a markedly slowed dissociation from receptors after pretreatment of membranes with micromolar concentrations. Pretreatment of membranes with 10 uM DALCE, followed by extensive washing, produced an 85-90% loss of 3H-DPDPE binding sites. D-Ala2,D-Leu5-enkephalin (DADLE), D-Ser2,Leu5,Thr6-enkephalin (DSTLE) and DPDPE produced losses of 59%, 70%, and 19%, respectively. The effect of DALCE was not reversed by a 60 min post-incubation in buffer containing 250 mM NaCl + 100 uM GMPPNP, a condition which produced nearly complete reversal of loss of sites by DADLE and DSTLE. DPDPE could be dissociated merely by post-incubation in TRIS-buffer alone for 15 min. The order for ease of dissociation after preincubation was DPDPE much greater than DADLE greater than DSTLE much greater than DALCE. The effect of DALCE was selective for delta sites, although higher concentrations of DALCE produced loss of mu sites. DALCE pretreatment had no effect on recovery of kappa sites. These results indicate that DALCE binds essentially irreversibly to delta receptors.

Animals↗
PubMed1985

Astrocytes secrete basal lamina after hemisection of rat spinal cord.

Basal lamina is reconstructed over the lesioned surface of the spinal cord. The following experiment (90 rats) studies the ultrastructure of the formation of this membrane and the immunohistochemistry of laminin production (a major secreted component of basal lamina). After hemisection of the spinal cord at T6 animals were prepared for electron microscopy or antilaminin-biotin-avidin-peroxidase incubation. Three-5 days posthemisection, antilaminin reaction product was observed in astrocytes and their processes which faced the lesion, endothelia of blood vessels or pia. Ultrastructurally (3 days), basal lamina was polymerizing as small projections on the surface of astrocytic membranes facing the lesion, endothelia or pia. By 5 days the basal lamina was a single membrane, folded multiple sheets or in swirls. At 6-10 days the antilaminin reaction and the basal lamina (except for duplications) did not differ from normal. Reactive astrocytes secrete laminin for at least 3-5 days after hemisection and form basal lamina on the lesioned surface of the spinal cord after spinal cord hemisection.

Animals↗
PubMed1984

Ultrastructure of fetal spinal cord and cortex implants into adult rat spinal cord.

The ultrastructure of cortex and spinal cord from 11-, 12-, and 15-day-old fetuses implanted into the spinal cord of adult rats was studied over 3 months. Under deep Chloropent anesthesia, a 0.5 X 1.0-mm square of fetal cortex or a 1.0-mm segment of fetal spinal cord was implanted subpially between the left dorsal column and the dorsal horn of 70 adult rats. Implants grew toward gray matter, usually interfacing with the host at the isthmus between the horns of the spinal cord. However, implants were observed that occupied the entire left dorsal and ventral horns of the left half of the host spinal cord. Implants had concentric zones: A central zone with basal lamina lined joined channels and subjacent neuroglia; a zone of differentiating implant nervous system; a zone with basal lamina lined implant with overlying pial cells on the dorsal and lateral surfaces of the implant; a zone that interfaced with the host with overlapping neuropil on the lateral and ventral surfaces of the implant. Neuron types were typical for cortical or spinal implants. Implants survived for 3 months and reached stages of neuronal and neuroglial maturation similar to controls. Both fetal spinal cord and brain were successful as implants, had delayed differentiation, and formed complex neuropils. The zone of overlapping interface of the donor and host is an anatomical indication of physiological and functional integration.

Animals↗
PubMed1976

[Not Available].

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History, Modern 1601-↗
PubMedDate not supplied

Appendicitis diagnosis today: clinical and ultrasonic deductions.

A total of 111 patients referred with a diagnosis of suspected "appendicitis" were entered into a prospective study. The surgeon and radiologist in charge of ultrasonography made separate diagnoses, and their findings were then combined and discussed as indications for surgery. Clinically, a history of pain migration proved to be reliable (p < 0.0001) as a diagnostic indicator, in contrast to nausea and initial irregularity of bowels. The duration of symptoms was significantly shorter in patients with proved appendicitis than among patients with negative findings (median 24 hours compared with 41 hours, p < 0.04). Among patients with perforated appendicitis, the symptomatic history was prolonged (not significantly) by 3 hours. Peritoneal signs such as pain on percussion, rebound tenderness, guarding, and a leukocytosis of more than 13,000/mm3 were indicative of appendicitis (p = 0.0001 for each sign). Lively bowel sounds excluded the possibility of appendicitis (p = 0.001). Scanty bowel sounds, rectal tenderness, axillorectal temperature difference, and a left shift in leukocytes were of no diagnostic significance. The doctor's "clinical experience" is significant at the level of p < 0.03. On ultrasonography, the following signs were indicative of appendicitis: periappendicular infiltration (p = 0.0003), a visible "cockade," and an appendix larger than 12 mm in diameter (p = 0.04). For 75% of the patients the surgeon was sure of his own clinical diagnosis and did not allow himself to be influenced by the sonographic findings. In 12% of doubtful cases ultrasonographic results decisively favored operation, and in 4.5% (n = 5) it prevented an unnecessary laparotomy in the presence of positive clinical symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗