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Biomedical subjects

J M Zhang

Publications and source records attributed to J M Zhang.

At least 73 records · Page 4Linked to original sources
PubMed1987

Intraglomerular tubular epithelial cells. A marker of glomerular hematuria.

The occurrence of intraglomerular tubular epithelial cells (ITEC) was investigated in 202 consecutive renal biopsy specimens and were present in 111 (55%). Minimal, focal, or diffuse glomerular diseases were all represented. Of the patients with ITEC 110 (99%) had gross or microscopic hematuria, either alone or associated with proteinuria; however, ITEC were found only in one of 79 proteinuric patients with no documented hematuria. Intraglomerular tubular epithelial cells did not occur in four patients with drug-induced interstitial nephritis and microscopic hematuria, or in 11 normal controls. The pathogenesis of ITEC is not known, but our data indicate that the phenomenon is almost constantly found in association with glomerular hematuria. Identification of ITEC, therefore, should help to confirm the glomerular origin of hematuria when histologic alterations are minimal.

Biopsy↗
PubMed1986

Helical structure of Bordetella pertussis fimbriae.

The helical structures of Bordetella pertussis fimbriae of serotypes 2 and 6 were determined by optical diffraction analysis of electron micrographs of negatively stained paracrystalline bundles of purified fimbriae. The fimbrial structure is based on an axial repeat of 13 nm that contains five repeating units in two complete turns of a single-start helix. This structure was confirmed by direct measurements of mass per unit length for individual fimbriae performed by dark-field scanning transmission electron microscopy of unstained specimens. These data further established that the helically repeating unit is a monomer of fimbrial protein (Mr congruent to 22,000 for type 2 and Mr congruent to 21,500 for type 6). Radial density profiles calculated from the scanning transmission electron micrographs showed that the fimbria has peak density at its center, i.e., no axial channel, consistent with the results of conventional negative-staining electron microscopy. The radial profile gives an outermost diameter of approximately 7.5 nm, although the peripheral density is, on average, diffuse, allowing sufficient intercalation between adjacent fimbriae to give a center-to-center spacing of approximately 5.5 nm in the paracrystals. Despite serological and biochemical differences between type 2 and type 6 fimbriae, the packing arrangements of their fimbrial subunits are identical. From this observation, we infer that the respective subunits may have in common conserved regions whose packing dictates the helical geometry of the fimbria. It is plausible that a similar mechanism may underlie the phenomenon of phase variations in other systems of bacterial fimbriae.

Bordetella pertussis↗
PubMed1986

Epstein-Barr virus seroepidemiology in China.

Since 1978 more than 300,000 sera from normal individuals were screened serologically in NPC high risk areas and prospective studies were carried out. Many patients were diagnosed in early stage. For example, in Wuzhou city, 20,726 persons over 40 years of age were screened; 1,138 persons were found to have IgA VCA antibody. Among them 18 NPC cases were detected; an additional 21 NPC patients were found within 5 year follow-up studies. Altogether there were 39 NPC patients. As compared to the patients in outpatient clinics, the frequency of NPC in stage I increased from 1.7% to 38.5% and in early stage (I + II) increased from 32% to 92.3%. IgA VCA antibody can be detected 5 years before the diagnosis of NPC in early stage was made. The detection rate of NPC from IgA VCA antibody-positive persons is 38-374 times the incidence rate of NPC in the general population of the same age group. Follow-up studies on the change of IgA VCA antibody titer in antibody-positive and antibody-negative groups were also carried out for years. 10.9% of antibody-positive individuals became antibody negative and 5.4% seronegative persons converted to positive within 4 years. Eighty-eight per cent of NPC patients were detected in the group of no change of antibody titer or in the group of increasing antibody titer. No NPC patients were found in the original antibody negative group.

Antibodies, Viral↗
PubMed1986

Nephropathy induced in a nephritis-resistant inbred mouse strain with the use of a cationized antigen.

C3H/HeN mice produce small amounts of antibody when challenged daily with 4 mg horse spleen apoferritin and fail to develop significant renal histologic and immunohistologic lesions. When the same dose of antigen is given in cationized form, glomerular deposits of both antigen and IgG, often accompanied by C3, are uniformly found in all animals. Thus it appears that cationized antigens can induce the formation of potentially damaging immune complexes in low-antibody-producing individuals that are not ordinarily susceptible to this kind of immune injury.

Animals↗
PubMed1985

Purification and characterization of fimbriae isolated from Bordetella pertussis.

Fimbriae were detached from Bordetella pertussis by mechanical shearing and purified by successive precipitations with ammonium sulfate, phosphate buffer (pH 6.0), and magnesium chloride. In each of these purification steps, the fimbriae aggregated into bundles as seen by electron microscopy. These aggregates could be disaggregated at pH 9.5. By electron microscopy, the purified fimbriae appeared as long filaments with a diameter of 5 nm. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified fimbriae showed a single protein subunit with a molecular weight of 22,000. The purified fimbriae did not have hemagglutinating activity when assayed with several types of erythrocytes, and they were antigenically, chemically, and structurally distinct from the filamentous hemagglutinin of B. pertussis. The purified fimbriae were also identified as serotype 2 agglutinogens, since antibody to the purified fimbriae agglutinated B. pertussis strains serotyped as 1.2.4, 1.2.3, or 1.2.3.6 but did not agglutinate those serotyped as 1.3.6.

Agglutination↗
PubMed1985

Purification of serotype 2 fimbriae of Bordetella pertussis and their identification as a mouse protective antigen.

Fimbriae were removed from Bordetella pertussis by mechanical shearing and purified by successive precipitations with ammonium sulfate, pH 6.0 phosphate buffer, and magnesium chloride. Electron microscopy showed the purified fimbriae to be long filamentous structures (5 nm in diameter) which aggregated into bundles at pH 6.0. Sodium dodecyl sulfate gel electrophoresis of the purified fimbriae gave a single protein subunit with a molecular weight of 22,000. The purified fimbriae did not have hemagglutinating activity when assayed with a variety of erythrocytes and were shown to be antigenically and structurally distinct from the filamentous hemagglutinin of B. pertussis. The purified fimbriae were identified as serotype 2 agglutinogens as antibody to the purified fimbriae agglutinated B. pertussis strains serotyped as 1.2.4, 1.2.3, or 1.2.3.6, but did not agglutinate serotypes 1.3.6. Immunization of mice with the purified fimbriae (14 micrograms) protected them from a lethal respiratory infection with strain 18323 (agglutinogen serotype 1.2.3.4.6) or with strain 432 (serotype 1.3.6). Immunization of mice with purified fimbriae containing 0.02% LPF also protected them from a lethal intracerebral infection with 18323. The ED50 was about 13 micrograms. Fimbriae containing less than 0.005% LPF did not protect mice from intracerebral challenge.

Animals↗