Behavioural cues of reproductive status in seahorses Hippocampus abdominalis

A method is described to assess the reproductive status of male Hippocampus abdominalis on the basis of behavioural traits. The non-invasive nature of this technique minimizes handling stress and reduces sampling requirements for experimental work. It represents a useful tool to assist researchers in sample collection for studies of reproduction and development in viviparous syngnathids, which are emerging as important model species.

Identification of a uniquely southern African clade of coastal pipefishes Syngnathus spp

The taxonomic status of two southern African coastal pipefish species, Syngnathus temminckii and Syngnathus watermeyeri, was investigated using a combination of morphological and genetic data. Morphological data showed that S. temminckii is distinct from the broadly distributed European pipefish Syngnathus acus, and a molecular phylogeny reconstructed using mitochondrial DNA recovered S. temminckii and S. watermeyeri as sister taxa. The southern African species share an evolutionary origin with north-eastern Atlantic Ocean and Mediterranean Sea species, including S. acus. These data support the existence of a distinct southern African clade of Syngnathus pipefishes that has diverged in situ to form the two species present in the region today.

The evolutionary origins of Syngnathidae: pipefishes and seahorses

Despite their importance as evolutionary and ecological model systems, the phylogenetic relationships among gasterosteiforms remain poorly understood, complicating efforts to understand the evolutionary origins of the exceptional morphological and behavioural diversity of this group. The present review summarizes current knowledge on the origin and evolution of syngnathids, a gasterosteiform family with a highly developed form of male parental care, combining inferences based on morphological and molecular data with paleontological evidence documenting the evolutionary history of the group. Molecular methods have provided new tools for the study of syngnathid relationships and have played an important role in recent conservation efforts. Despite recent insights into syngnathid evolution, however, a survey of the literature reveals a strong taxonomic bias towards studies on the species-rich genera Hippocampus and Syngnathus, with a lack of data for many morphologically unique members of the family. The study of the evolutionary pressures responsible for generating the high diversity of syngnathids would benefit from a wider perspective, providing a comparative framework in which to investigate the evolution of the genetic, morphological and behavioural traits of the group as a whole.

Genetic monogamy despite social promiscuity in the pot-bellied seahorse (Hippocampus abdominalis)

Sexual selection theory predicts a positive correlation between relative parental investment and mate choice. In syngnathid fishes (seahorses and pipefish), males brood offspring in specialized brooding structures. While female-female mating competition has been demonstrated in some pipefishes, all seahorses (genus Hippocampus) studied to date have been found to have conventional sex roles with greater male-male competition for access to mates despite possessing the most complex brood structures in the family. Although multiple mating is common in pipefish, seahorses are again exceptional, exhibiting strict genetic monogamy. Both demographic and behavioural explanations have been offered to explain the lack of multiple mating in seahorse species, but these hypotheses have not yet been explicitly addressed. We investigated mating systems and brood parentage of the pot-bellied seahorse, Hippocampus abdominalis, a temperate-water species that is socially promiscuous with conventional sex roles in laboratory populations. We observed promiscuous courtship behaviour and sex-role reversal in high density, female-biased field populations of H. abdominalis. We hypothesize that sex roles are plastic in H. abdominalis, depending on local population density and sex ratio. Despite promiscuous courtship behaviour, all assayed male seahorses were genetically monogamous in both laboratory and wild populations. Physiological limitations associated with embryo incubation may explain the absence of multiple mating in seahorses and may have played an important role in the development of the unique reproductive behaviour typical in these species.

Genetic signature of recent glaciation on populations of a near-shore marine fish species (Syngnathus leptorhynchus)

Continental glaciation has played a major role in shaping the present-day phylogeography of freshwater and terrestrial species in the Northern Hemisphere. Recent work suggests that coastal glaciation during ice ages may have also had a significant impact on marine species. The bay pipefish, Syngnathus leptorhynchus, is a near-shore Pacific coast fish species with an exceptionally wide latitudinal distribution, ranging from Bahia Santa Maria, Baja California to Prince William Sound, Alaska. Survey data indicate that S. leptorhynchus is experiencing a range expansion at the northern limit of its range, consistent with colonization from southern populations. The present study uses six novel microsatellite markers and mitochondrial DNA (mtDNA) sequence data to study the present-day population genetic structure of four coastal populations of S. leptorhynchus. Deficits in mtDNA and nuclear DNA diversity in northern populations from regions glaciated during the last glacial maximum (LGM) [c. 18 000 years before present (bp)] suggest that these populations were effected by glacial events. Direct estimates of population divergence times derived from both isolation and isolation-with-migration models of evolution are also consistent with a postglacial phylogenetic history of populations north of the LGM. Sequence data further indicate that a population at the southern end of the species range has been separated from the three northern populations since long before the last interglacial event (c. 130 000 years bp), suggesting that topographical features along the Pacific coast may maintain population separation in regions unimpacted by coastal glaciation.

Interspecies mating in sympatric species of Syngnathus pipefish

Hybridization is thought to be an important source of novel genetic variation, and interspecific hybridization may increase the adaptive potential of wild populations. While hybridization has not been previously reported in syngnathid fishes (seahorses and pipefish), the sympatric occurrence of closely related species at high densities increases the probability of interspecies mating in this group. Southern California is home to five species of Syngnathus pipefish, and these species frequently co-occur in near-shore eelgrass beds along the California coast. Recent work has identified exceptionally high levels of genetic diversity in southern populations of Syngnathus leptorhynchus, a widespread species which ranges from Mexico to Alaska. Microsatellite genotyping and mitochondrial sequence data are used here to study the population genetics of S. leptorhynchus and S. auliscus at a site in San Diego Bay where they are found to co-occur at high densities. While no adult hybrids were detected in the study population, analysis of male broods indicates that interspecies mating is occurring between the two species. The lack of premating isolating mechanisms between these two relatives suggests that hybridization may be common in sympatric species of Syngnathus.

Determination of CD59 protein in normal human serum by enzyme immunoassay, using octyl-glucoside detergent to release glycosyl-phosphatidylinositol-CD59 from lipid complex

In this study we have optimised the enzyme immunoassay (ELISA) to quantify CD59 antigen in human serum or plasma. The glycosyl-phosphatidylinositol (GPI)-linked form of CD59 is known to complex with serum high-density lipoprotein. For ELISA optimisation, therefore, we investigated the effect of detergents, added to the sample diluent, on the determined values of CD59. Values obtained in the presence of octyl-glucoside (OG) for 20 adults aged 18-35 years and 17 children 1-5 years old were, respectively, 33-119 ng/ml (mean +/- S.D.: 66+/-22 ng/ml) and 37-143 ng/ml (76+/-33 ng/ml). These results were higher than those measured without OG and were in contrast with published results showing absence, or eight to nine times lower levels, of the protein in serum. A known range for serum concentrations of CD59 in healthy individuals will establish an important reference point for clinical work and for the investigation of diseases involving the complement membrane attack complex (MAC) and its regulation.

An aberrant form of CD59 derived from HeLa cells

We isolated a CD59 cDNA from a HeLa cell library which encoded a mutated form of CD59, having a single base substitution (G to T) that changed Arg55 to Met. Since this mutation occurred in the vicinity of the putative active site of CD59, we expressed the aberrant form of the protein in Chinese hamster ovary cells in order to test for effects upon function. We found that the mutation did not influence complement inhibitory activity of CD59. However, the epitopes recognised by the function-blocking CD59 monoclonal antibodies BRIC229 and YTH 53.1 were significantly affected. The G to T substitution caused loss of an Mnl I restriction site which permitted PCR-RFLP analysis. All of 52 human subjects studied, and our in-house HeLa cells, were homozygous for the normal CD59 sequence, indicating that the altered sequence was not due to normal variation in the general population. Therefore this mutation probably arose spontaneously in the HeLa cell line used to generate the commercially obtained cDNA library.

Male pregnancy in seahorses and pipefishes (family Syngnathidae): rapid diversification of paternal brood pouch morphology inferred from a molecular phylogeny

In contrast to the majority of vertebrate species, primary male parental care is common in fishes and encompasses a remarkable diversity of adaptations. Seahorses and pipefishes (Family Syngnathidae) exhibit some of the most specialized forms of paternal care in animals and so are ideally suited to the study of the evolution of male parental care. During mating, female syngnathids transfer eggs to specialized morphological structures that are located on either the abdomen or tail of the male. The male provides all postfertilization parental care and has morphological and physiological adaptations to osmoregulate, aerate, and even nourish the developing embryos. While all syngnathid species are adapted for paternal care, the brooding structure with which this is accomplished varies between species, from simple ventral gluing areas to much more complex structures such as the completely enclosed pouches of the seahorses. Our combined cytochrome b-, 12S rDNA-, and 16S rDNA-based molecular phylogeny of syngnathid fishes demonstrates that rapid diversification of male brooding structures has been associated with the major evolutionary radiation of the group, suggesting that development and diversification of structures involved in paternal care may have been key evolutionary innovations of the Syngnathidae. Molecular analyses also highlight geographical centers of biodiversity and suggest interoceanic migration of Syngnathus pipefishes from their center of origin in the Pacific.

Incipient speciation in sympatric Nicaraguan crater lake cichlid fishes: sexual selection versus ecological diversification

The growing body of empirical evidence for sympatric speciation has been complemented by recent theoretical treatments that have identified evolutionary conditions conducive to speciation in sympatry. The Neotropical Midas cichlid (Amphilophus citrinellum) fits both of the key characteristics of these models, with strong assortative mating on the basis of a colour polymorphism coupled with trophic and ecological differentiation derived from a polymorphism in their pharyngeal jaws. We used microsatellite markers and a 480 bp fragment of the mitochondrial DNA control region to study four polymorphic populations of the Midas cichlid from three crater lakes and one large lake in Nicaragua in an investigation of incipient sympatric speciation. All populations were strongly genetically differentiated on the basis of geography. We identified strong genetic separation based on colour polymorphism for populations from Lake Nicaragua and one crater lake (Lake Apoyo), but failed to find significant genetic structuring based on trophic differences and ecological niche separation in any of the four populations studied. These data support the idea that sexual selection through assortative mating contributes more strongly or earlier during speciation in sympatry than ecological separation in these cichlids. The long-term persistence of divergent cichlid ecotypes (as measured by the percentage sequence divergence between populations) in Central American crater lakes, despite a lack of fixed genetic differentiation, differs strikingly from the patterns of extremely rapid speciation in the cichlids in Africa, including its crater lakes. It is unclear whether extrinsic environmental factors or intrinsic biological differences, e.g. in the degree of phenotypic plasticity, promote different mechanisms and thereby rates of speciation of cichlid fishes from the Old and New Worlds.

Antigen S1, encoded by the MIC1 gene, is characterized as an epitope of human CD59, enabling measurement of mutagen-induced intragenic deletions in the AL cell system

S1 cell membrane antigen is encoded by the MIC1 gene on human chromosome 11. This antigen has been widely used as a marker for studies in gene mapping or in analysis of mutagen-induced gene deletions/mutations, which utilized the human-hamster hybrid cell-line, AL-J1, carrying human chromosome 11. Evidence is presented here which identifies S1 as an epitope of CD59, a cell membrane complement inhibiting protein. E7.1 monoclonal antibody, specific for the S1 determinant, was found to react strongly with membrane CD59 in Western blotting, and to bind to purified, urinary form of CD59 in ELISAs. Cell membrane expression of S1 on various cell lines always correlated with that of CD59 when examined by immunofluorescent staining. In addition, E7.1 antibody inhibited the complement regulatory function of CD59. Identification of S1 protein as CD59 has increased the scope of the AL cell system by enabling analysis of intragenic mutations, and multiplex PCR analysis of mutated cells is described, showing variable loss of CD59 exons.

Identification of MIC 11 antigen as an epitope of the CD59 molecule

The MIC 11 antigen is expressed on human cells and is characterized by reaction with a monoclonal antibody (mAb), 16.3A5. The gene controlling MIC 11 was recently mapped to the p13 region of chromosome 11 within 500 kb of the gene encoding CD59, a complement regulatory protein. The present report investigates the antigenic relationship between these cell-membrane determinants and sets out evidence that MIC 11 and CD59 are encoded by the same gene. Western blotting of human erythrocyte membrane proteins and purified membrane CD59 showed that 16.3A5 anti-MIC 11 antibody bound to a 19-24,000 MW band with the characteristic appearance of CD59 protein, and gave staining patterns identical to those obtained with the CD59 antibody, BRIC 229. The binding of 16.3A5 monoclonal IgG to purified urine-derived CD59 in enzyme-linked immunosorbent assay (ELISA) was inhibited by YTH 53.1 rat CD59 antibody, indicating that the MIC 11 epitope is the same as, or close to, that recognized by CD59 antibodies such as YTH 53.1, BRIC 229 and 2/24. Prior exposure of erythrocytes to 16.3A5 anti-MIC 11 also reduced the ability of the CD59 antibodies, BRIC 229 and YTH 53.1, to block the complement-inhibiting function of membrane CD59. Anti-MIC 11 antibody alone, however, had no inhibitory effect on CD59 function. This may be due to its relatively low binding affinity or to some slight difference in epitope specificity. Further studies using immunofluorescence showed that the MIC 11 epitope, like CD59, is absent from EBV-B cells lacking GPI-anchored proteins and from a B-cell line specifically deficient in CD59 protein. Overall, the results provide strong evidence that MIC 11 is a determinant on the CD59 molecule.

The immunosuppressive drug thalidomide induces T helper cell type 2 (Th2) and concomitantly inhibits Th1 cytokine production in mitogen- and antigen-stimulated human peripheral blood mononuclear cell cultures

Thalidomide is an effective immunomodulatory drug in man, but its mechanism of action remains unclear. We hypothesized that, in addition to its reported inhibitory effects on production of monocyte-derived tumour necrosis factor-alpha (TNF-alpha), thalidomide might be effective at the level of Th immunoregulation. In a comparative study with the immunosuppressant cyclosporin A, we have demonstrated a potent and specific effect of thalidomide on cytokine production relating to the distinct Th1 and Th2 subsets. It induced and enhanced the production of IL-4 and IL-5 and, at the same dose (1000 ng/ml), significantly inhibited interferon-gamma (IFN-gamma) production in phytohaemagglutinin (PHA)-stimulated human peripheral blood mononuclear cell (PBMC) cultures. Stimulation of PBMC with recall antigen (streptokinase:streptodornase (SKSD)) at 144 h in the absence of thalidomide resulted in a predominantly Th1 response, with the production of IFN-gamma and IL-2. Thalidomide switched this response from a Th1 to a Th2 type. The effect was most pronounced at 1000 ng/ml thalidomide, where inhibition of IFN-gamma and enhancement of IL-4 production was maximal. In unstimulated cultures thalidomide alone induced IL-4 production. Cyclosporin A, in contrast, inhibited both Th1 and Th2 cytokine production by PHA-stimulated PBMC. Time course data from thalidomide-treated cultures revealed that the augmented IL-4 production diminished as the culture time increased, whereas IFN-gamma production was significantly increased. This response might be due to activation-induced apoptosis of Th2 cells or the induction of Th2 cell anergy, in the continued presence of stimulating agents, with the emergence of IFN-gamma-secreting Th1 cells when Th2 antagonism declines. The effects of thalidomide and related compounds may enhance our understanding of the mechanisms of T helper cell selection, offer the possibility of controlled therapeutic switching between Th1 and Th2 responses, and may lead to a rational approach for the treatment of some T cell-mediated immunological disorders.

The profiles of interleukin (IL)-2, IL-6, and interferon-gamma production by peripheral blood mononuclear cells from house-dust-mite-allergic patients: a role for IL-6 in allergic disease

We have developed a model to measure cytokine production by peripheral blood mononuclear cells (PBMC) in vitro. In this report, we examine the production of interleukin-2 (IL-2), IL-6, and interferon-gamma (IFN-gamma) by PBMC of house-dust-mite (Dermatophagoides pteronyssinus)-allergic subjects. When stimulated with specific allergen (D. pteronyssinus), PBMC of patients produced significant levels of IL-2 and high levels of IL-6, but little or no IFN-gamma. Nonatopic control PBMC also produced IL-6, although at lower levels, but no IL-2 or IFN-gamma. A ubiquitous antigen, streptokinase/streptodornase (SKSD), induced high levels of IL-2 in patients, but only low levels of IFN-gamma and IL-6. Nonatopic controls produced similar levels of IL-2 and IL-6, but high levels of IFN-gamma to SKSD. IL-2 and IFN-gamma levels induced by the T-cell mitogen phytohaemagglutinin (PHA) were similar in patient and control groups, but IL-6 levels were significantly lower in the patients. IgE synthesis in vitro was shown only in atopic PBMC cultures stimulated with specific allergen. The major points can be summarized as 1) IL-2 production by atopic patients in response to allergen; 2) IL-6 production to allergen by both atopic and nonatopic patients, but significantly increased in atopic patients; and 3) defective IFN-gamma production by atopic patients to both allergen and antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparative study of IgG subclass antibodies in patients allergic to wasp or bee venom

IgG1 and IgG4 antivenom antibody responses were compared in groups of patients who had experienced systemic reactions to wasp (Vespula spp.) or bee stings. Pretreatment serum IgG4 antibody levels were low in both groups, but IgG1 antibodies were significantly raised in bee-allergic patients (P < 0.002), probably reflecting their greater exposure to stings than wasp-reactive patients. No direct or indirect relationships were found, in untreated bee or wasp patients, between IgG1, IgG4, or IgE antibody levels and the severity of a patient's last systemic reaction to a sting. After a 12-week course of venom immunotherapy (VIT), IgG1 antibodies increased significantly only in wasp-sensitive patients (P < 0.001), although both groups responded with marked increases in venom-specific IgG4 (P < 0.01). Wasp-allergic subjects who responded to VIT with high production of specific IgG4 showed the greatest increases (pre- to post-VIT) in IgE antibodies (P < 0.05). This group also demonstrated a direct correlation (P < 0.05) between post-VIT levels of IgE and IgG1 antibodies, a finding contrary to an IgE-immunoregulatory role for IgG1. High levels of venom-specific IgG1 alone, or in combination with IgG4, were not protective in three patients who suffered repeated adverse reactions to bee VIT, showing that absolute levels of IgG subclass antivenom antibodies are not reliably indicative of clinical responsiveness in individual patients.

Venom-specific IgG antibodies in bee and wasp allergy: lack of correlation with protection from stings

This paper investigates the relationship between venom IgG levels and protection from stings. Venom-specific IgG antibody levels have been measured by radioimmunoassay in untreated wasp-(n = 38) and bee-allergic (n = 16) patients presenting with systemic reactions to stings and in a sub-group of these (wasp = 15; bee = 9), before and after the initial course of venom immunotherapy (VIT). A history was taken of all reactions, the last systemic reaction being graded on a scale of 1-8 and of the number and timing of stings. In untreated patients venom IgG levels were much higher in bee-allergic patients (mean +/- s.e. = 68.2 +/- 7.1% positive pool) than in the wasp group (27.1 +/- 4.2%) (P < 0.05 Mann-Whitney U-test). There was a marked rise in venom IgG after the initial course of VIT in the wasp group (geometric mean and 95% confidence intervals = 40.5%, 28.8-54.3) but a much smaller rise in the bee group (15.3%, 6.6-24.1), with no overlap in the 95% confidence intervals. Bee patients, who were mainly beekeepers or their relatives, had been more heavily immunized with venom than wasp patients. They had received: (i) more stings (mean number of stings: bee, 26; wasp, 4; P < 0.001) and (ii) more stings per year. Wasp patients received their smaller number of stings over a much longer period, up to 40 yr. There was no correlation between the severity of the last systemic reaction and the venom IgG levels alone or venom IgG and IgE levels in combined analysis in either bee or wasp patients. This study shows that the pattern of IgG response differs in bee and wasp-allergic subjects, and that most bee-allergic subjects with systemic reactions have high levels of venom IgG. The degree of immunization with venom seems to be an important determinant of the venom IgG level. Our findings suggest that venom-specific IgG levels do not predict systemic reactions to stings and are not useful for monitoring VIT. If protection from stings is IgG-mediated, our observations suggest that the relevant immune response is more complex, possibly involving IgG sub-classes, IgG antibodies to individual venom antigens or antibody affinity, and not adequately reflected by measurement of the concentration of venom-specific IgG.

A competitive inhibition ELISA for the quantification of human interferon-gamma

A competitive enzyme immunoassay has been developed for the measurement of human interferon-gamma (IFN-gamma) in cell culture supernatants. The assay is based on the dose-dependent inhibitory effect of liquid phase IFN-gamma on the binding of a specific monoclonal antibody to recombinant IFN-gamma (rIFN-gamma) immobilized on microtitre plate wells. The extent of monoclonal anti-IFN-gamma inhibition was determined by the uptake of alkaline phosphatase-conjugated goat anti-mouse IgG and the subsequent development of enzyme substrate colour. Absorbance readings were taken and results for test samples were extrapolated from standard rIFN-gamma inhibition curves constructed as logit-log plots. Assay performance was assessed using three different monoclonal antibodies (clones 20G7, H-22 and GZ-4). Optimum sensitivity was achieved with the antibodies of higher affinity, 20G7 and H-22, which gave reliable quantification of IFN-gamma over a wide range of concentrations from 0.4 ng/ml (3.4 IU/ml), or less, to 250 ng/ml approximately 2000 IU/ml). The inhibition assay incorporates the advantages of specificity, reproducibility and convenience of performance which are the hallmarks of monoclonal antibody-based ELISAs. However, compared to the sandwich ELISAs previously described for human IFN-gamma, it is considerably more economical in its use of monoclonal anti-IFN-gamma, requiring < 50 ng of a single antibody per 96 well plate. It also uses relatively small volumes of test samples (50 microliters/well) which is particularly advantageous where limited amounts of cell culture supernatant are available for cytokine assays.

Lateral rotatory dislocation of the ankle without fracture

A 34-year-old woman sustained a closed lateral rotatory dislocation of the ankle without a fracture. Treatment was by closed reduction and cast immobilization for 6 weeks. After removal of the cast, her ankle was stable. Stress radiographs of both the affected and contralateral ankles were normal. One year after injury the patient demonstrated a full, pain-free, stable range of motion. The patient exhibited generalized ligamentous laxity, which may have contributed to her tendency to dislocate the talus within the mortise.

Interleukin-2-induced production of interferon-gamma by resting human T cells and large granular lymphocytes: requirement for accessory cell factors, including interleukin-1

Between 5 and 20% of normal human lymphocytes were found to synthesize interferon-gamma (IFN-gamma) in primary cultures with recombinant interleukin-2 (rIL-2). After 22 hr, IFN-gamma-producing cells included CD5+ T lymphocytes, CD16+ large granular lymphocytes (LGL), and a population of CD5-, CD16- blast cells. Only a small proportion (0-7%) of IFN-gamma-synthesizing cells expressed HLA-DR. The production of IFN-gamma by all rIL-2-responding lymphocyte subsets was shown to require the presence of DR+ accessory cells, probably including nonadherent, esterase-negative monocytes and/or dendritic cells. Accessory cell function in lymphocyte preparations depleted of DR+ cells, or in purified (greater than or equal to 95%) suspensions of LGL, was fully replaced either by addition of 2% autologous, adherent monocytes or by monocyte culture supernatant. The activity of monocyte supernatant was greatly reduced by treatment with antiserum specific for human interleukin-1 beta (IL-1 beta), although a combination of rIL-1 beta and rIL-2 failed to stimulate IFN-gamma production in DR- lymphocytes. These results indicate that rIL-2-induced IFN-gamma synthesis in both T cells and LGL requires the synergistic activity of IL-1, and possibly of one or more other monokines, as yet unidentified.

Direct antibody rosette-forming reactions using monoclonal markers of lymphocyte subpopulations. Methodology and applications illustrated by investigations with rat pan-T antibodies of the CAMPATH series

A sensitive direct antibody rosette assay has been developed for the detection of antigens on the lymphocyte cell membrane. Indicator cells for rosette tests were prepared by chromic chloride coupling of rat or mouse monoclonal IgG or IgM anti-lymphocyte antibodies to untreated or trypsinized bovine red blood cells. The monoclonal antibodies used were reactive with a range of cell surface markers which identify various lymphocyte subpopulations, including T cell antigens, HLA class II (Ia-like antigens), Leu-7 (HNK-1) and VEP 13, a determinant of Fc gamma receptors on large granular lymphocytes. Results obtained by direct rosette formation correlated well with those of parallel tests using indirect immunofluorescent antibodies staining. Several applications of the direct antibody rosetting procedure are described in further investigations with a series of pan-T monoclonal (CAMPATH) antibodies. These include the morphological examination of antibody-binding cells in cytocentrifuge smears, the separation of lymphocyte subsets by density gradient centrifugation, and the use of a rosette inhibition assay to identify monoclonal antibodies binding to the same (or closely associated) epitopes of the lymphocyte cell membrane.

An in vivo and in vitro study of selenium deficiency and infection in rats

Selenium deficiency in rats impairs the ability of neutrophils and peritoneal macrophages to kill Candida albicans organisms in vitro. In contrast, killing of Salmonella typhimurium and Staphylococcus aureus organisms is unaffected by the deficiency. Survival of rats after intraperitoneal injection of 8 X 10(7) S. aureus organisms was not affected by Se deficiency, but a 5-fold increase in the dose (4 X 10(8) S. aureus organisms) led to a significantly greater mortality in the Se deficient rats.

Rat diaphragm: changes in muscle fiber type frequency with age

This study demonstrates age-related changes in fiber type, distribution, and diameter that suggest that the diaphragm does not attain a static pattern of fiber type in adults. Furthermore, the progressive increase in the FG fiber diameters may be of importance in the interpretation of physiologic and biochemical parameters measured in the diaphragm muscle of animals of different age groups.

Fc gamma-receptor-bearing, non-B lymphocytes in human peripheral blood: cytophilic immunoglobulin binds almost exclusively to large granular lymphocytes

Cytophilic IgG (CYT-Ig) has previously been reported to bind to both the "TG" (E+, Fc gamma R+) and "L" (E-, Fc gamma R+) subsets of non-B lymphocytes in human peripheral blood. Present investigations show that IgG-binding cells, as detected by a sensitive antiglobulin rosetting reaction, are contained almost entirely within the large granular lymphocyte (LGL) subpopulation, and that fewer than 5% of other non-B lymphocytes acquire IgG from serum. Cell membrane-bound IgG sterically blocks the reaction of LGL with sheep red blood cells and therefore influences the proportions of these cells characterized as TG (E+) or L (E-) lymphocytes. Although the majority of TG lymphocytes are LGL, a further subpopulation of E+, Fc gamma R+ cells are detectable under particular test conditions. Unlike LGL, these lymphocytes do not react with rabbit IgG-coated ox RBC (EAG) in saline, but will form EAG rosettes when the reaction is enhanced in the presence of Ficoll. These Fc gamma R+ cells are mostly of typical small-lymphocyte morphology and do not bind detectable amounts of CYT-Ig, nor do they express the monoclonal antibody-defined VEP 13 determinant associated with Fc gamma R on LGL.

Discrimination between innate and cytophilic immunoglobulin on human peripheral blood lymphocytes: analysis by the direct antiglobulin rosette-forming reaction

Bovine red blood cells linked to polyclonal or monoclonal anti-immunoglobulin antibodies are used in the direct antiglobulin rosetting reaction to detect surface-Ig on human lymphocytes. The sensitivity of this test is markedly increased by pretreating the red cells with trypsin. Enzyme-treated red cells, coupled to anti-human Fab or anti-light chain antibodies, react not only with innate Ig on B lymphocytes but also with smaller amounts of passively adsorbed, cytophilic Ig on up to 25% of freshly prepared peripheral blood (non-B) lymphocytes. In contrast, trypsinized red cells carrying anti-Ig isotype-specific antibodies react exclusively with B cell surface-Ig. Cytophilic Ig is abnormally firmly bound to lymphocytes separated on Ficoll-Hypaque at 20 degrees C or below, and is released very slowly during 3 h or more at 37 degrees C in vitro. Lymphocytes are free of detectable cytophilic Ig when isolated on Ficoll-Hypaque at 37 degrees C, and very little Ig is retained by non-B cells in suspensions purified on Percoll which, unlike Ficoll, does not increase Ig binding affinity. These lymphocyte separation procedures are recommended as a preliminary to B cell assays by sensitive antiglobulin techniques.

Effect of zinc deficiency on muscle fibre type frequencies in the post-weanling rat

Male weanling rats were maintained on diets either deficient or adequate in zinc for a period of 4 weeks. The rats on the deficient diet showed a reduction in food intakes and growth. After 4 weeks both soleus muscles and the lateral portion of the diaphragm were studied histochemically to examine the relative frequencies of the fibre types. The soleus muscles of the deficient animals showed a significant change in the proportion of slow and fast fibres. The diaphragm muscles of the deficient animals had a significant increase in the proportion of fast-twitch oxidative glycolytic fibres and a significant decrease in fast-twitch glycolytic fibres compared with the controls. Stainable lipid increased in the diaphragm muscle of the deficient animals with respect to their pair-fed controls.

Mitochondrial abnormalities in muscle from vitamin B12-deficient sheep

Skeletal and cardiac muscles from vitamin B12-deficient sheep were examined. Histochemical studies did not reveal any gross pathological changes in the muscle structure, but there was an abnormal distribution of the product of the NADH-diaphorase reaction. Electron microscopy revealed an abnormal distribution of mitochondria, changes in the number and arrangement of cristae within the mitochondria and the presence of inclusions. The possibility that alterations in mitochondrial morphology are early lesions attributable to metabolic changes in vitamin B12 deficiency is discussed.

Thiaminase activity in the gut of cobalt-deficient sheep

In an attempt to clarify the reported relationship between cobalt deficiency and the incidence of cerebrocortical necrosis (CCN), sheep were fed on a diet deficient in cobalt. High levels of thiaminase activity were found regularly in rumen and faeces samples from cobalt-deficient animals, and also from controls supplemented with cobalt or vitamin B12. There was a poor correlation between thiaminase activity and viable counts of the thiaminase-producing organisms Clostvidium spovogenes and Bacillus spp. Urinary excretion of thiamine appeared normal. When the sheep were killed, normal concentrations of thiamine were found in the liver. The sheep were deficient in vitamin B12, as judged by the concentrations in serum and liver, by urinary excretion of methylmalonic acid, and by clinical condition. Twitching and weakness were observed, but clinical signs of CCN did not develop.

Evidence that the fourth component of complement (C4) is carried on a high proportion of normal guinea-pig B lymphocytes

The fourth component of complement (C4) has been demonstrated on the cell membrane of guinea-pig B lymphocytes isolated from blood, lymph nodes and spleen. In lymph nodes, at least, the C4-positive cells also carry receptors for C3 and most bind IgG-Fc. Few, if any, T lymphocytes have detectable C4. Resynthesis of cell-surface C4 could not be shown following in vitro culture of lymphocytes stripped of C4 by proteolytic enzymes, and it is likely that the C4 is passively acquired in vitro from tissue fluids, possibly by a mechanism similar to that involved in the binding of C4 (Chido and Rodgers determinants) to human erythrocytes.

Interaction of antibody-aggregated C4 and guinea-pig red cells: coagglutination phenomenon of Bordet and Gengou

The component of bovine serum (coagglutinogen) responsible for coagglutination of guinea-pig red cells has been shown to be c4, as anticipated from our previously reported findings on human serum. To effect coagglutination, the C4 needs to be aggregated by antibody; thereby probably increasing the avidity of the C4 for the receptors on guinea-pig red cells. The coagglutinating activity is lost if univalent Fab anti-C4 is used, but it can be restored by adding IgG antibody to the Fab. A procedure is described for producing antibody reagents to human or bovine C4 by injecting guinea-pigs with well-washed coagglutinated guinea-pig red cells.

Receptors on guinea-pig erythrocytes specific for cell-bound fourth component of human complement (C4)

Guinea-pig erythrocytes have receptors for heterologous (human and rabbit) complement activated by the classical pathway on cell surfaces. This was shown in the present study by rosette-forming reactions of guinea-pig erythrocytes and human lymphocytes or sheep erythrocytes pre-treated with antibody and human R3 complement. The binding is temperature-dependent and is enhanced by treating the guinea-pig erythrocytes with neuraminidase. The receptors were shown to be specific for C4 by inhibition tests employing a range of anti-human complement antibodies (including anti-Clq, -Cl inhibitor, -C4, -C2, -C3 and -C3b inactivator). Of these reagents, only anti-C4 inhibited the receptor activity, indicating that the guinea-pig erythrocyte C4-receptors differ from those on lymphocytes, monocytes, polymorphonuclear leucocytes and human erythrocytes which are reported to react with both C3b and C4b. In contrast to the strong affinity observed for heterologous C4, guinea-pig erythrocytes appear to react very weakly, if at all, with homologous C4.

The coagglutination phenomenon of Bordet and Gengou involves a reaction between antibody-aggregated fourth component of complement and a receptor on guniea pig red cells

The coagglutination phenomenon of Bordet and Gengou has been re-investigated. Many of the original observations have been confirmed. However, the explanation of the phenomenon has been found to be more special than that offered by Bordet and Gengou, who envisaged 'entrainment; or enmeshment of guinea pig red cells by lattices formed by antibodies reacting with serum proteins. We found that, so far as human serum is concerned, coagglutination of guinea pig red cells is confined to an activity of the fourth component of complement following its reaction with antibody. The nature of the association between antibody-reacted or antibody-aggregated C4 and the receptor on the guinea pig red cells is still to be elucidated.

The evaluation of an intervention program for young schoolchildren with acting-out problems

The rationale and nature of a program to train nonprofessional child-aides for helping interactions with young acting-out school children are described. Pre/post teacher measures of children's problems and competencies, aide measures of problem behavior, and school mental health professionals' change in behavior estimates were used to evaluate the program's effectiveness. Children seen by trained aides showed significantly greater reductions both in acting-out problems and in overall maladjustment than did similar children seen by comparable aides who did not have additional training, or by themselves before training. Implications were considered for optimizing outcomes both in the specific school intervention project in question and in other, broader types of clinical interventions.

Receptors for activated C3 on thymus-dependent (T) lymphocytes of normal guinea-pigs

In a survey of lymphocyte subpopulations in normal guinea-pig blood, lymph node, spleen, thymus and peritoneal cavity, a considerable overlap was observed between the percentages of C3-receptor bearing lymphocytes (CRL) and of thymus-dependent (T) cells in lymph nodes. Simultaneous rosette-formation reactions with sheep erythrocytes carrying rabbit complement (EAC) and papain-treated rabbit erythrocytes (a T-cell marker) revealed that 20--50% of the lymph node CRL were T lymphocytes. These experiments and others on cell suspensions depleted of Ig-bearing (B) lymphocytes showed that between 8 and 36% of lymph node T cells have complement receptors. The frequency of T-CRL in other lymphoid tissues was lower, representing between 0 and 8% of the T-cell population. The reaction of T-CRL and EAC was not inhibited by EDTA which is known to inhibit the C3 receptor activity on macrophages.

In vitro complement activation by rabbit lymphocytes and thymocytes in autologous serum

The activation of C3, previously demonstrated to occur during the isolation of lymphocytes from rabbit blood, has been investigated further by in vitro exposure of blood and lymph node lymphocytes and thymocytes to autologous serum. Activated C3 deposited on the lymphoid cell-surface was detected by (i) anti-C3, (ii) immune adherence reaction, and (iii) blocking of receptors for C3. An affinity shown by guinea-pig erythrocytes for activated complement was also investigated. Using EGTA, which inhibits the classical complement pathway while leaving the alternative pathway unaffected, it was shown that either pathway may be activated by rabbit cells depending on the temperature of incubation. The classical pathway was triggered at 4 degrees, probably by the reaction of cold auto-antibodies with lymphoid cell-surface determinants. At 37 degrees, however, comlement activation followed the alternative pathway in a similar manner to that reported by other workers with human lymphoblastoid cell lines.

Artefactual variations in the B and T subpopulations of rabbit blood lymphocytes depending on method of isolation, and blocking of C3 receptors due to in vitro activation of complement

Marked differences were found in the proportions of lymphocyte subpopulations in rabbit peripheral blood depending on the techniques used for the purification of lymphocytes. Rosette-forming reactions were used to find the numbers of T lymphocytes, Ig-bearing cells and cells with receptors for C3 or IgG-Fc. Some of the methods used for lymphocyte separation altered the relative numbers of T and B lymphocytes, through a disproportionate loss of T cells. Other changes were due to in vitro activation of complement detectable by the presence of C3 on the lymphocyte cell-membrane and causing partial blocking of C3 receptors. Highest yields of lymphocytes were obtained from defibrinated blood treated with carbonyl iron to remove phagocytes and methyl cellulose to sediment erythrocytes. This procedure was accompanied by in vitro activation of complement, with the consequences mentioned. Complement activation was inhibited by taking the blood into either EDTA or citrate. As EDTA was cytotoxic for rabbit T lymphocytes, citrate was considered best although the resulting lymphocyte suspensions were contaminated with up to 25% granulocytes and monocytes owing to the inhibition of carbonyl iron uptake by the prior exposure to citrate.