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Biomedical subjects

B Nagy

Publications and source records attributed to B Nagy.

At least 145 records · Page 8Linked to original sources
PubMed1979

[Leukocyte function in colostrum (author's transl)].

Breast milk, especially colostrum was analysed quantitatively and qualitatively as well as the function of various cell types in it. The phagocyte activity of the mass of leukocytes consisting predominantly of macro- and microphages approaches the phagocyte index of leukocytes of the newborn infant, however, neither of them reaches the level of adults.--The lymphocytes traceable in a minor proportion produce secretory IgA as well as IgG.--On the basis of literary data the authors discuss the literature and their own results regarding the immunobiological significance of breast milk.

Colostrum↗
PubMed1978

Calcium-induced conformational changes in a cyanogen bromide fragment of troponin C that contains one of the binding sites.

The increase observed in alpha helix from 20 to 38%, the spectral red shift of the absorption bands of the side chain chromophores, the increase of phenylalanine side chain optical activity and a decrease of cysteinyl side chain reactivity with 5,5'-dithiobis(2-nitrobenzoic acid) are consistent with a coil to helix change in the segment containing Cys-98 and Phe-99 and 102 when the CB9 fragment of troponin C (TnC) with an intact binding site III binds Ca2+. Since similar spectrophotometric observations have been made on the whole molecule the data with CB9 confirm our previous suggestion that binding site III of TnC is one of the strong binding sites for Ca2+. The estimate of the binding constant of Ca2+ for CB9 is about 2 orders of magnitude lower than in whole TnC, indicating further stabilization in the intact molecule.

Calcium↗
PubMed1978

Immunization of suckling pigs against enteric enterotoxigenic Escherichia coli infection by vaccinating dams with purified pili.

Pregnant swine (gilts) were vaccinated parenterally with a suspension of purified pili from the porcine enterotoxigenic Escherichia coli strain 987 (09:K103::NM). Gilts injected with placebo served as controls. Suckling pigs born to gilts in both groups were challenged intragastrically with virulent strain 987. The percentage of deaths, incidence and duration of diarrhea, numbers of E. coli in the ilea, and E. coli attachment to the villous epithelia were significantly less in suckling pigs of vaccinated gilts than in those of controls. These results are consistent with the hypothesis that pili of some enterotoxigenic E. coli facilitate adhesion to intestinal epithelia. Vaccination of dams with pili appears to be a means of immunizing against diarrheal disease caused by enterotoxigenic E. coli in suckling neonates. This work confirms the role of somatic pili as colonization and virulence factors and provides another example of safe and effective purified pilus vaccines.

Animals↗
PubMed1977

Circular dichroic and perturbation spectra of aromatic chromophores in rabbit tropomyosin. Topography of tyrosine residues.

1. Difference spectra of tryosyl residues obtained on denaturation of tropomycosin with urea or guanidinium chloride indicate that strong hydrophobic environments exist in the native coiled-coil state. 2. Solvent perturbation difference spectra indicate that tyrosyl residues are partially accessible to the solvent. The accessiblity decreases with increasing size of the solvent molecules. 3. Spectral pH titration of tyrosyl residues cannot provide information on the tyrosyl accessibility because conformational change accompanies the increase in pH. 4. Circular dichroism of tyrosyl and phenylalanyl residues is consistent with the effect of imposed conformational rigidity on the partially asymmetrical vibrational fine structure of the 1Lb absorption band of phenyl and benzyl chromophores; the effect is reduced by 70% on unfolding of tropomyosin.

Animals↗
PubMed1977

Fibrinolysis associated with human neoplasia: production of plasminogen activator by human tumours.

The plasminogen-dependent fibrinolytic activity of several human tumours has been studied. The following neoplastic tissues, which were obtained from cancer patients by either surgery or biopsies, were examined: cervical, mammary, prostatic, ovarian, lung carcinomas, melanoma, basalioma. Fibrinolysis was measured in lysates either of tumour tissue specimens or of respective cell cultures. This measurement was based on release of radioactivity from 125I-fibrin-coated Petri dishes. All examined tumours showed elevated levels of plasminogen-dependent fibrinolytic activity. However, normal control tissues had little or no activity. These results indicate that the fibrinolysis might be useful in differentiating between malignant and normal tissues.

Breast Neoplasms↗
PubMed1977

Colonization of porcine small intestine by Escherichia coli: colonization and adhesion factors of pig enteropathogens that lack K88.

The colonizing and adhesive attributes of enterotoxigenic acapsular and/or nonpiliated mutants from K88-negative enteropathogenic Escherichia coli strains were compared with their capsulated and piliated parents (parents were piliated when grown in vitro and in vivo). Acapsular, nonpiliated mutants from three different colonizing strains of enteropathogenic E. coli lost their ability to colonize the ileum of newborn pigs. Acapsular, piliated and capsular, nonpiliated mutants were derived from one of the parental strains (987), and both mutants lacked the ability to colonize the ileum of pigs. The only mutants available from a fourth strain (431) were acapsular and piliated, and they colonized as well as their parents. These data indicate that both capsule and pili are involved in colonization by strain 987. In contrast, capsule is not required for colonization by strain 431, but pili may be.

Animals↗
PubMed1977

Intestinal colonization and adhesion by enteroxigenic Escherichia coli: ultrastructural observations on adherence to ileal epithelium of the pig.

Colonization of pig ileum by enterotoxigenic Escherichia coli that were enteropathogenic for pigs but that lacked K88 antigen (K88-) resulted in morphological characteristics similar to those reported for K88+ strains. Strains of enterotoxigenic E. coli from three different K88-serotypes adhered to the villous epithelium. In sections examined by transmission electron microscopy, adherent bacteria were separated from each other and from epithelial microvilli by peribacterial electron-lucent regions. The enterotoxigenic E. coli had appendages that extended into these regions. The appendages were morphologically characteristic for each strain. It is possible that these appendages were pili, polysaccharide K antigens, or structures resulting from some interaction between pili and polysaccharide. Certain pili or pilus-like structures may be virulence attributes that facilitate adhesion of enterotoxigenic E. coli to the intestinal epithelium.

Animals↗
PubMed1977

Occurrence of K99 antigen on Escherichia coli isolated from pigs and colonization of pig ileum by K99+ enterotoxigenic E. coli from calves and pigs.

Several strains of enterotoxigenic Escherichia coli (ETEC) isolated from pigs were found to have an antigen (K99) previously reported only on strains of calf and lamb origin and which facilitates intestinal colonization in the latter two species. Several human ETEC were also tested for K99; however, none were positive. Each of four K99-positive ETEC strains of calf origin and one of pig origin produced K99 in pig ileum in vivo, adhered to villous epithelium in pig ileum, colonized pig ileum, and caused profuse diarrhea in newborn pigs. In contrast to the K99-positive strains above, four K99-negative ETEC from humans and chickens and one K99-positive ETEC from a calf either did not colonize pig ileum or did so inconsistently. When the K99-negative strains did colonize, they had little or no tendency to adhere to intestinal villi. These results are consistent with the hypothesis that K99 facilitates adhesion to and colonization of pig ileum by some ETEC.

Animals↗
PubMed1977

Colonization of porcine intestine by enterotoxigenic Escherichia coli: selection of piliated forms in vivo, adhesion of piliated forms to epithelial cells in vitro, and incidence of a pilus antigen among porcine enteropathogenic E. coli.

In contrast to K88-positive porcine enterotoxigenic Escherichia coli (ETEC), K88-negative porcine ETEC strains did not adhere to isolated intestinal epithelial cells in vitro. However, they did adhere to intestinal epithelium in vivo. Growth of one such ETEC (strain 987) in pig small intestine consistently yielded a greater percentage of piliated cells than did growth in vitro. This increase was demonstrable by electron microscopy, by change in colonial morphology, and by agglutination in specific antisera against the pili of strain 987. In contrast to the stored stock culture (which contained very few piliated cells), richly piliated forms of strain 987 did adhere to isolated intestinal epithelial cells in vitro. A series of porcine E. coli strains was tested for agglutinability in antiserum against the pili of strain 987, and several K88-negative ETEC strains were agglutinated. These data are consistent with the hypothesis that pili facilitate intestinal adhesion and colonization by K88-negative ETEC strains.

Antigens, Bacterial↗
PubMed1976

Colonization of porcine small intestine by Escherichia coli: ileal colonization and adhesion by pig enteropathogens that lack K88 antigen and by some acapsular mutants.

Seven K88-negative porcine enteropathogenic Escherichia coli, representing three different serogroups, caused severe diarrhea and characteristically colonized the ileum, but not the jejunum, of intragastrically exposed newborn pigs. Bacterial counts of intestinal contents and wall, fluorescence, and scanning electron microscopy all suggested that these strains colonized the ileum by adhesion to the villous epithelium. However, in ligated intestinal loops, these enteropathogenic E. coli strains adhered to jejunal epithelium as well as to ileal epithelium. Acapsular (K-) mutants, derived from one of the principal strains, retained their colonizing and adhesive abilities, whereas K- mutants from three other enteropathogenic E. coli strains did not. It is suggested that: (i) these K88-negative enteropathogenic E. coli colonize the ileum by adhesion, and (ii) the adhesion of some K-88-negative strains is mediated by surface factors other than, or in addition to, the polysaccharide K antigen.

Animals↗
PubMed1976

Trace elements in the serum of mothers and their children.

The serum copper, zinc and iron levels, iron binding capacity and coeruloplasmin activity were determined in 28 maternal and cord bloods and in 50 infants and children. At the end of the gestation period the serum copper level increased, iron concentration remained unchanged while the level of zinc decreased significantly as compared to the values for healthy, non-pregnant women. Iron and zinc concentrations at birth were significantly higher in the newborn than in the mother, whereas the copper level amounted only to 20% of the maternal value. Subsequently, the copper level increased to reach the lower limit of healthy adults in the first to second year of life. The remarkably high neonatal zinc concentration fell significantly in the first 2 to 4 weeks of life and decreases to the normal adult level at one year of age. The changes in the trace element concentrations may be due to quantitative differences in the transporting proteins, variations in placental permeability and in the function of transfer proteins.

Ceruloplasmin↗
PubMed1976

Immunoglobulin E in the sera of infants and children.

The serum IgE level has been studied from birth up to 14 years of age. The mean serum IgE concentration was found to be correlated with age. Parallel measurements in cord blood and maternal blood yielded a mean of 25 I.U./ml (range, 0--90 I.U.) for the former and one of 124 I.U./ml (range, 50-600 I.U.) for the latter. The normal IgE level ranged from 20 to 100 I.U./ml in infants and from 100 to 200 I.U./ml in children, but even values of 400 to 600 I.U. did not necessarily reflect a pathological condition. In the majority of patients with eczema, urticaria and spastic bronchitis, high IgE levels were measured. The highest individual and mean values were obtained in children harbouring intestinal helminths, though a normal IgE level also occurred in such patients. In coeliac disease the values were within normal limits.

Acute Disease↗