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Biomedical subjects

J B Hay

Publications and source records attributed to J B Hay.

121 records · Page 7Linked to original sources
PubMed1972

Quantitative studies on the proliferation and differentiation of antibody-forming cells in lymph.

The transforming cells that appear in the efferent lymph from a lymph node responding to an antigenic challenge are part of a heterogeneous population which changes as the response progresses. Some cells containing small amounts of antibody appear early in the response and these cells have the cytologic characteristics of small and medium lymphocytes. They are, however, actively synthesizing DNA. As the immune response progresses, the antibody content of the cells in lymph increases. When incubated in vitro, cells in lymph appearing late in the response released 20 times more antibody per cell than those appearing early in the response. Large blast cells are the predominant antibody-forming cell in lymph. At the peak of a secondary challenge with horseradish peroxidase, up to 40% of the cells in lymph may be blast cells and, of these, two-thirds may contain specific antibody. It seems probable that most if not all of the blast cells responding to the antigen are involved directly in antibody and DNA synthesis. Cells in all stages of ultrastructural differentiation, and even mature plasma cells, were found to incorporate (3)H-thymidine into their nuclear DNA.

Animals↗
PubMed1972

Ultrastructural analysis of antibody synthesis in cells from lymph and lymph nodes.

A variety of cells containing antibody were found in lymph from sheep responding to secondary challenges with horseradish peroxidase. Antibody was present in blast cells in lymph within the perinuclear space, the endoplasmic reticulum, the Golgi apparatus and on polyribosomes. Some lymphocytes in lymph also contained antibody but in these cells it was located principally in the perinuclear space. No cells were found containing antibody distributed throughout their cytoplasm nor were any lymphocytes found with a Golgi apparatus positive for antibody. After the immune response in the lymph had died away, a population of cells containing antibody was still present in the regional lymph node. These were all plasma cells in which the antibody was present for the most part in a highly organized endoplasmic reticulum. Cells of this type were never found in the lymph. The cells containing the smallest amounts of antibody had a few discrete focal points in the perinuclear space and a few positive groups of ribosomes in their cytoplasm. The endoplasmic reticulum in some cells was filled completely with antibody, while in others positive segments were found adjacent to negative ones. The antibody in the cytoplasmic endoplasmic reticulum was in continuity with the antibody in the perinuclear space. The Golgi apparatus contained antibody in only a small proportion of the cells but when it was positive it was strongly so, suggesting that antibody was concentrated in this organelle. In some cells a positive reaction to horseradish peroxidase antibody appeared in the nucleus over the nucleoli. The significance of this finding is not known.

Animals↗
PubMed1970

Factors affecting the glycosphingolipid composition of murine tissues.

The effects of genetic strain, sex, age, and pathological state on the distribution and concentration of glycosphingolipids in mouse kidneys and livers were studied. The concentrations of glycosphingolipids and phospholipids in the kidneys and livers of different strains were compared. The major glycosphingolipid in the kidneys of male and female BALB/c, C3H/He, C57/BL, A, and C57xA (F(1) hybrid) mice was a sulfatide, monoglycosyl-(3-sulfate) ceramide; monoglycosyl ceramide was the major component in livers. The kidneys of males of all strains contained significant amounts of diglycosyl ceramide, but those of females contained, at most, only traces. Glycosphingolipid concentration in the male kidneys of C57/BL and C57xA (F(1) hybrid) was much higher than in the female and was also much higher than in the male kidneys of C3H/He, BALB/c, and A strains. The kidneys of "old" (36 wk) male and female C3H/He mice contained much higher proportions of monoglycosyl ceramide than 10-12-wk-old adults. The distributions of glycosphingolipids in kidneys of female C3H/He mice with BP8 ascites tumors and male C57xA (F(1) hybrid) mice with EL4 ascites tumors differed from those in the normal mice. An unknown lipid, present in all glycosphingolipid extracts from kidney and liver, was tentatively identified as cholesterol sulfate.

Age Factors↗
PubMed1965

The molecular structure of bacterial walls. The size of ribitol teichoic acids and the nature of their linkage to glycosaminopeptides.

1. Ribitol teichoic acids prepared by fractional precipitation of trichloroacetic acid extracts of bacterial cell walls are essentially undegraded and have similar chain length to the teichoic acid originally present in the walls. 2. The chain length of teichoic acid can be determined directly, without prior extraction from the wall. Accurate values have been obtained by measurement of the formaldehyde produced by oxidation of walls with periodate. Less accurate values have been derived from the amount of inorganic phosphate formed by heating walls at pH4. 3. The relative amounts of N-acetylglucosaminylribitol and its mono- and di-phosphates produced by heating walls of Staphylococcus aureus with alkali agree with the amounts calculated for the hydrolysis of teichoic acid having the chain length determined by other methods. 4. Chemical considerations indicate that the linkage between teichoic acid and the wall may involve a phosphoramidate bond between the terminal phosphate of the teichoic acid and one of the amino groups in the glycosaminopeptide.

Cell Wall↗
PubMedDate not supplied

Measurement of blood flow and vascular permeability changes in response to 12-O-tetradecanoyl-phorbol-13-acetate and to asbestos fibers.

The hyperemia (increased blood flow) and vascular permeability changes induced in rabbit skin by the tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate and by asbestos fibers have been quantitated. The resultant hyperemia, measured with radiolabeled microspheres, was inhibited in both cases by steroidal and nonsteroidal anti-inflammatory drugs. Since the inflammatory responses resulting from exposure to these agents might be important for the subsequent development of neoplasms, it is proposed that such a specific and quantitative technique be used to analyze the components of these inflammatory responses in more detail.

Administration, Topical↗
PubMedDate not supplied

A method for tracking the migration of blood lymphocytes.

A method has been devised for labeling whole blood with the fluorescent dye fluorescein isothiocyanate (FITC) so the migration of blood lymphocytes can be studied in the sheep. Although lymphocytes can be purified from blood using density gradient media or elutriation it is difficult to obtain a large number of cells, because many cells are usually lost during the purification steps. It is desirable to label at least 10(8)-10(9) lymphocytes for lymphocyte tracking studies, because a smaller number is difficult to subsequently detect and quantitate in blood and lymph even using flow cytometry. Also, it is desirable to minimize the in vitro manipulation of lymphocytes, because dead or damaged lymphocytes will not recirculate. By labeling all the cellular components of a sample of whole blood rather than first purifying the lymphocytes we have been able to satisfy both of these criteria. Although labeled blood cells of all types are reinjected into the animal, the lymphocytes are easily distinguishable from other cells using a flow cytometer. In these studies between 2.4-12.4 x 10(8) lymphocytes were injected intravenously, and they were detectable in the blood and lymph for at least 10 days. The recovery of FITC-labeled (FITC+) lymphocytes in efferent lymph is comparable to that of lymphocytes labeled with other fluorescent or radioactive markers. The presence of labeled non-lymphoid cells in the animal makes this technique impractical for studies of lymphocyte localization within histologic sections. However, it is useful for studies in animals in which lymphatic vessels can be cannulated and the blood-to-lymph recirculation of labeled lymphocytes monitored, and it also may be applicable for studies in which lymphoid organ suspensions are analyzed using flow cytometry.

Animals↗
PubMedDate not supplied

Recombinant bovine interferon-alpha I 1 inhibits the migration of lymphocytes from lymph nodes but not into lymph nodes.

Recombinant bovine interferon-alpha I 1 (IFN-alpha) was tested for effects on lymphocyte migration into and out of the lymph nodes of sheep. Chronic lymph drainage methods were used to monitor the efferent lymph of single lymph nodes of unanaesthetized animals. When IFN-alpha was injected into the drainage area of the lymph node, infused directly via an afferent lymphatic, or injected intravenously, a marked decrease in cell output was observed. Nanogram quantities of IFN-alpha produced an effect that lasted several hours. To test whether this effect was specific for lymphocytes, we first stimulated a lymph node with Staphylococcus aureus so that large numbers of neutrophils and lymphocytes were present in efferent lymph. When IFN-alpha was then injected, the lymphocytes disappeared from efferent lymph but the neutrophils did not. Normal efferent lymph cells were labeled with radioisotopes and injected intravenously during the IFN-alpha induced effect. The entry of lymphocytes from the blood was significantly enhanced at a time coinciding with the suppressed cell exit in the efferent lymph. Recovery data indicated that the lymphocytes were retained temporarily in the lymph node but were not destroyed. Furthermore, the bovine IFN-alpha does not appear to be conspicuously antigenic in sheep. It is not yet certain whether IFN-alpha enhances the interactions of cells within the lymph node thereby potentiating immunologic reactions.

Animals↗
PubMedDate not supplied

Reduced lymphatic drainage of dialysate from the peritoneal cavity during acute peritonitis in sheep.

OBJECTIVES: The purpose of this study was to investigate the effects of acute peritonitis on lymphatic drainage of the peritoneal cavity in conscious sheep. DESIGN: Peritonitis was induced with the addition of 1% casein or 1% albumin to the dialysis solution. Thirty sheep (5 groups of 6) were used in this study. One group received 50 mL/kg intraperitoneal infusions of Dianeal 4.25% (486 mOsm/L); a second group received 1% casein-Dianeal 4.25% (493 mOsm/L); a third group received 1% albumin-Dianeal 4.25% (487 mOsm/L). In the fourth and fifth groups (controls and casein-injected) lymph was collected from the caudal mediastinal lymph node and the thoracic duct, both of which are involved in the lymphatic drainage of the peritoneal cavity (peritonitis induced with casein). (125)I-human serum albumin (25 mu CI) was added to the dialysate as the lymph flow marker. Lymph drainage was estimated from (1) the appearance of the intraperitoneally administered tracer in the blood; (2) the disappearance of the tracer from the peritoneal cavity; and (3) the recovery of tracer in lymph. RESULTS: In noncannulated animals the cumulative volume removed by lymphatics over 6 hours (based on tracer recovery in blood) was 10.5 +/- 1.0 mL/kg in control animals versus 5.0 +/- 0.6 mL/kg and 8.6 +/- 1.2 mL/kg in casein and albumin-infused sheep, respectively. The suggestion of decreased lymph drainage in peritonitis was supported by the cannulation experiments. While the cumulative fluid removed from the peritoneal cavity over 6 hours in caudal lymph was unaffected by peritonitis (3.8 +/- 0.4 mL/kg in controls vs 3.6 +/- 0.5 mL/kg in casein-injected animals), peritonitis reduced flow into the thoracic duct from 3.0 +/- 0.3 to 1.1 +/- 0.3 mL/kg. The sum of the volume removed in lymph in the cannulated preparations was 6.8 +/- 0.4 mL/kg in controls versus 4.7 +/- 0.5 mL/kg in the peritonitis group. The total volume removed from the cavity (including an estimate of flow based on the residual recovery of tracer in blood) was reduced from 12.6 +/- 1.4 in controls to 7.8 +/- 0.6 mL/kg in the peritonitis sheep. In contrast, estimates of lymph drainage based on the disappearance of tracer from the peritoneal cavity suggested that lymph drainage increased (from 16.6 +/- 1.6 mL/kg in controls to 17.8 +/- 1.5 mL/kg and 25.5 +/- 1.7 mL/kg in the casein and albumin groups, respectively, in noncannulated animals and from 15.3 +/- 1.4 mL/kg in controls to 25.0 +/-1.7 mL/kg in the cannulated group). In both noncannulated and cannulated sheep the total recovery of tracer was less in the peritonitis groups. CONCLUSIONS: These studies demonstrated that lymph drainage of the peritoneal space was decreased in a casein peritonitis model. The decrease in lymph drainage is most obvious in the visceral pathway leading to the thoracic duct; however, diaphragmatic drainage into the right lymph duct may also be inhibited. The disappearance of tracer from the peritoneal cavity was elevated during peritonitis. Tracer disappearance has been used to estimate lymph drainage, but this approach suggested, incorrectly, that lymph flow had increased.

Acute Disease↗