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Biomedical subjects

S H Love

Publications and source records attributed to S H Love.

At least 19 recordsLinked to original sources
PubMed1982

Increased hyaluronic acid is associated with dermal delayed-type hypersensitivity.

Rabbits sensitized subcutaneously with heat-killed bacilli Calmette-Guerin (BCG) and challenged intradermally with heat-killed BCG or purified protein derivative (PPD) demonstrated classical dermal delayed-type hypersensitivity which peaked two days postchallenge. Animals challenged with BCG developed dermal granulomas as measured by induration and gross observation. Challenge with either PPD or BCG resulted in increased levels of dermal hyaluronic acid (HA) by two days postchallenge. Dermal HA returned to normal levels by seven days postchallenge regardless of the challenge antigen. These results indicated that increased HA is associated with dermal delayed-type sensitivity, but increased HA is not associated with dermal granulomatous hypersensitivity. These results are in contrast to previously reported work which indicates that increased HA is associated with both pulmonary delayed hypersensitivity and pulmonary granulomatous hypersensitivity.

Animals↗
PubMed1981

Role of Ca2+ and Mg2+ in neutrophil hexose transport.

The influence of extracellular Ca2+ and Mg2+ on the transport of 2-deoxy-[3H]glucose into human polymorphonuclear neutrophils was studied. Omission of these cations from the cell suspensions had little effect on resting hexose uptake. Furthermore, the addition of the bivalent cation chelator, EDTA, depressed uptake only slightly. Similarly, neither cation was essential for the enhanced 2-deoxy-D-[3H]glucose uptake stimulated by two chemotactic factors (C5a and N-formylmethionylleucylphenylalanine) and arachidonic acid: enhanced uptake was only partially depressed by the omission of Ca2+ and Mg2+ from the suspensions and was still prominent in the presence of EDTA. Two other neutrophil stimulants, the ionophores, A23187 and ionomycin, also enhanced hexose uptake but their actions were heavily dependent upon extracellular bivalent cations and were totally abrogated by EDTA. In all instances, extracellular Ca2+, but not Mg2+, supported optimal enhanced hexose transport induced by stimuli. Activation of 2-deoxy-D-[3H]glucose uptake by each of the five stimuli was totally blocked by cytochalasin B (a blocker of carrier-mediated hexose transport) and D-glucose but not by L-glucose. The data indicate, therefore, that a variety of neutrophil stimulants activate carrier-mediated hexose transport. Although this transport can be triggered by the movement of extracellular Ca2+ into the cell (as exemplified by the action of the two ionophores), such Ca2+ movement is not required for the actions of chemotactic factors or arachidonic acid. Other mechanisms, such as a rearrangement of intracellular Ca2+, may be involved in mediating the activation of hexose transport induced by the latter stimuli.

Biological Transport, Active↗
PubMed1981

Quantitation of glycosaminoglycans of rabbit lung during delayed-type hypersensitivity reactions and granuloma formation.

The specificity and kinetics of hyaluronic acid (HA) accumulation in relation to other glycosaminoglycans (GASs) were determined in rabbit lungs during an allergic granulomatous response to BCG, an allergic nongranulomatous response to tuberculoprotein, and during a foreign-body granulomatous response to carrageenan. Hyaluronic acid was the only GAG detected in the lung lavage fluids. Hyaluronic acid occurred in the airways on day two of the allergic granulomatous response, but its presence in the airway did not correlate with ensuing granuloma formation in the parenchyma. Generalized increases in GAG of the parenchyma also peaked on day two of the DTH responses. Generalized increases in GAG peaked on day five during the foreign-body granulomatous response to carrageenan. A persistently elevated level of HA in the lung tissue correlated with granuloma formation but not with the intensity of the response.

Animals↗
PubMed1981

Selective desensitization of neutrophils: further studies with 1-O-alkyl-sn-glycero-3-phosphocholine analogues.

Human polymorphonuclear neutrophils aggregate and degranulate in response to 2 recently described platelet-activating phospholipids: 1-O-alkyl-2-O-acetyl-sn-glycero-3-phosphocholine and 1-O-alkyl-2-O-ethyl-sn-glycero-3-phosphocholine. Here, we find that the 2 phospholipids can also desensitize neutrophils. Thus, cells incubated with either phosphocholine for 1 to 5 min in the absence of calcium and magnesium (which are required for aggregation) did not aggregate when exposed to the bivalent cations and fresh lipid stimulus. Also, cells incubated with either lipid for 5 min in the absence of cytochalasin B (which is required for degranulation) did not degranulate when exposed to cytochalasin B and fresh lipid stimulus. However, these desensitized neutrophils aggregated and degranulated fully in response to the chemotactic oligopeptide N-formyl-methionyl-leucylphenylalanine and C5a. In relation to the aggregation response, this selective desensitization was not due to lipid inactivation; it persisted after thorough cell washing; and it was not induced by a nonaggregating analogue, 1-O-alkyl-sn-glycerol-3-phosphocholine. Furthermore, cells desensitized to the formylated oligopeptide or C5a (by preincubation with either stimulus in the absence of bivalent cations) did not aggregate when challenged with the oligopeptide or C5a, respectively, but exhibited a normal or enhanced aggregation response to the 2 active phospholipids. These data support the concept that C5a, formylated oligopeptides, and phosphocholines represent 3 distinct classes of stimulants that activate and densensitize neutrophils by at least partially independent pathways. This activation and desensitization may be mediated by 3 types of cellular receptors, each of which interacts with only 1 class of stimuli.

Animals↗
PubMed1980

Reversal of non-depolarising neuromuscular block in children: a comparison of atropine and glycopyrrolate in a mixture with neostigmine.

Atropine and glycopyrrolate were compared when given in a mixture with neostigmine for the reversal of non-depolarising neuromuscular block in children. Glycopyrrolate was an effective antimuscarinic agent and could be safely used as an alternative to atropine, although the advantages in this age group were not as marked as have been observed in adults.

Atropine↗
PubMed1980

Participation of hyaluronic acid in the macrophage disappearance reaction.

Hyaluronic acid accumulates in the peritoneal cavity of mice during the macrophage disapperance reaction. Macrophages reappear in the exudates during the depletion of hyaluronate. The disappearance reaction is simulated by the intraperitional (i.p.) injection of hyaluronic acid into normal mice. The disapperance reaction largely is inhibited by the simultaneous injection (i.p.) of specific hyaluronidase with the challenge dose of BCG. We propose that hyaluronic acid makes a major contribution to the macrophage disappearance reaction.

Animals↗
PubMed1980

Additional evidence for the role of hyaluronic acid in the macrophage disappearance reaction.

A slight macrophage disappearance reaction was elicited in C3H/Hej mice, a low responder strain. Low levels of hyaluronic acid accumulated in the peritoneal fluid during the disappearance reaction, in keeping with the low response. The macrophage disappearance reaction was not simulated by the intraperitoneal injection of large amounts of hyaluronate into nonsensitized C3H/Hej mice. This suggested that these macrophages were refractory to hyaluronic acid. Subsequent experiments demonstrated that low concentrations of hyaluronic acid did not agglutinate these cells, in vitro, nor inhibit their migration to the extent obtained with macrophages from the responder mice (C57BL/6 strain), thus providing evidence that the low responder mice had at least two defects with respect to the disappearance reaction: 1) they accumulated less hyaluronic acid in their peritoneal fluid, and 2) their macrophages were refractory towards hyaluronic acid. Generalized defects in membranes of various cell types of C3H/Hej mice, involving receptors for lymphokines in the case of mesothelial cells, or hyaluronic acid receptors on macrophages may serve as the central defect and explain the above observations.

Agglutination↗
PubMed1980

Properties of colony-stimulating and inhibiting activities of chicken serum.

Serum obtained from young chicks stimulated with endotoxin contained elevated levels of colony-stimulating activity (CSA). This CSA was partially characterized. Incubation at 65 degrees C (60 min) had no effect on the ability of the CSA to support colony formation by nonadherent cells but reduced 3-4 fold its ability to support colony formation by unfractionated marrow cells. These data suggest that most of the serum activity is due to a heat-labile, adherent cell-dependent factor which does not directly affect the nonadherent granulocyte/monocyte colony-forming cell (GM-CFC). The ability of serum to support colony formation was increased by chloroform extraction. This was evidently due to the presence of inhibitory lipoproteins. The lipoprotein fraction of pigeon serum was found to directly block colony formation. The CSA for nonadherent cells migrated as one peak in the postalbumin region during zone electrophoresis. When electrofocused, heterogeneity was detected but all activity was associated with molecules with isoelectric points between pH 4 and 5. Following sequential fractionation by chloroform extraction, ultrafiltration, zone electrophoresis, isoelectric focusing and gel filtration (Ultrogel AcA 44), the activity was separated from most of the remaining protein. One peak of activity was obtained at the excluded volume.

Animals↗
PubMed1976

Production of a precursor to the pyrimidine moiety of thiamine.

The supernatant fluid from cultures of Escherichia coli W-11, a pur E mutant, prevented the inhibition of growth of E. coli B in a medium containing adenine or adenosine. Adenine inhibition was prevented more readily than adenosine inhibition. More than 90% of the biological activity of the supernatant fluid was recovered in the anionic fraction after treatment with Dowex-50 (NH4+). The cationic fraction, containing large amounts of 5-aminoimidazole ribonucleoside (AIRS), did not prevent adenine inhibition. The W-11 supernatant fluid was shown by bioautography to contain only one compound that prevented adenine inhibition. Proliferating and non-proliferating cultures produced only one compound that prevented adenine inhibition. The compound was shown to be an intermediate (int-1) in the biosynthesis of the pyrimidine moiety of thiamine, Int-1 was stable during sterilization at 121 C for 15 min, during concentration by either flask evaporation or lyophilization, and after storage for several days at 4 C or at -- 20 C. Int-1 was distinguishable from other known derivatives or intermediates of the pyrimidine moiety. A scheme is presented that illustrates the proposed relationship between int-1 and the synthesis of thiamine.

Adenine↗
PubMed1972

Characterization of S-adenosylmethionine: ribosomal ribonucleic acid-adenine (N 6 -) methyltransferase of Escherichia coli strain B.

This study is concerned with the isolation and characterization of the enzyme, S-adenosylmethionine:ribosomal ribonucleic acid-adenine (N(6-)) methyl-transferase [rRNA-adenine (N(6)-) methylase] of Escherichia coli strain B, which is responsible for the formation of N(6)-methyladenine moieties in ribosomal ribonucleic acids (rRNA). A 1,500-fold purified preparation of the species-specific methyltransferase methylates a limited number of adenine moieties in heterologous rRNA (Micrococcus lysodeikticus and Bacillus subtilis) and methyl-deficient homologous rRNA. The site recognition mechanism does not require intact 16 or 23S rRNA. The enzyme does not utilize transfer ribonucleic acid as a methyl acceptor nor does it synthesize 2-methyladenine or N(6)-dimethyladenine moieties. Mg(2+), spermine, K(+), and Na(+) increase the reaction rate but not the extent of methylation; elevated concentrations of the cations inhibit markedly. The purified preparations utilize 9-beta-ribosyl-2,6-diaminopurine (DAPR) as a methyl acceptor with the synthesis of 9-beta-ribosyl-6-amino-2-methylaminopurine. A comparison of the two activities demonstrated that one methyltransferase is responsible for the methylation of both DAPR and rRNA. This property provides a sensitive assay procedure unaffected by ribonucleases and independent of any specificity exhibited by rRNA methyl acceptors.

Adenine↗