Development of cardiac sensitivity to oxygen deficiency: comparative and ontogenetic aspects.

Hypoxic states of the cardiovascular system are undoubtedly associated with the most frequent diseases of modern times. They originate as a result of disproportion between the amount of oxygen supplied to the cardiac cell and the amount actually required by the cell. The degree of hypoxic injury depends not only on the intensity and duration of the hypoxic stimulus, but also on the level of cardiac tolerance to oxygen deprivation. This variable changes significantly during phylogenetic and ontogenetic development. The heart of an adult poikilotherm is significantly more resistant as compared with that of the homeotherms. Similarly, the immature homeothermic heart is more resistant than the adult, possibly as a consequence of its greater capability for anaerobic glycolysis. Tolerance of the adult myocardium to oxygen deprivation may be increased by pharmacological intervention, adaptation to chronic hypoxia, or preconditioning. Because the immature heart is significantly more dependent on transsarcolemmal calcium entry to support contraction, the pharmacological protection achieved with drugs that interfere with calcium handling is markedly altered. Developing hearts demonstrated a greater sensitivity to calcium channel antagonists; a dose that induces only a small negative inotropic effect in adult rats stops the neonatal heart completely. Adaptation to chronic hypoxia results in similarly enhanced cardiac resistance in animals exposed to hypoxia either immediately after birth or in adulthood. Moreover, decreasing tolerance to ischemia during early postnatal life is counteracted by the development of endogenous protection; preconditioning failed to improve ischemic tolerance just after birth, but it developed during the early postnatal period. Basic knowledge of the possible improvements of immature heart tolerance to oxygen deprivation may contribute to the design of therapeutic strategies for both pediatric cardiology and cardiac surgery.     

Immune response deficiency of BSVS mice. II. Generalized deficiency to thymus-dependent antigens.

BSVS mice gave abnormally low IgG responses to 5 thymus-dependent antigens as well as a weak delayed-type hypersensitivity (DTH) response to sheep red blood cells. In contrast to IgG, the IgM antibody responses of these mice were normal to three T-independent antigens as well as to all five T-dependent antigens. The low immune responsiveness of BSVS mice was also reflected in the low levels of IgG(2)a, IgG(2)b and IgG(3) in their normal serum. The low T-dependent immune responses may result from BSVS mice having been selectively bred for susceptibility to infection with St. Louis encephalitis virus and Salmonella. C57BL/6J mice, which are also highly susceptible to Salmonella, gave low immune responses similar to, but genetically distinct from, those of BSVS mice. The levels of Ig-positive and theta-positive cells were normal in BSVS and C57BL/6J mice.     

Visceral leishmaniasis in congenic mice of susceptible and resistant phenotypes: T-lymphocyte-mediated immunosuppression.

This paper continues a comparative study (A. D. Nickol and P. F. Bonventre, Infect. Immun. 50:160-168, 1985) describing immune responses exhibited by congenic, Lshs mouse strains C57B1/10 (cure) and B10.D2 (noncure) during the course of disseminated leishmaniasis. We report that sublethal whole-body irradiation of B10.D2 mice before challenge with Leishmania donovani converted the noncuring mice to a curing phenotype. Splenic lymphocytes from L. donovani-infected B10.D2 mice failed to proliferate in response to parasite antigen stimulation in vitro. Splenic lymphocytes from irradiated, cured B10.D2 mice regained the capacity to respond to the parasite antigen stimulus. Transfer of T cells but not B cells from L. donovani-infected B10.D2 mice prevented the acquisition of immunity and recovery from infection in X-irradiated mice. In addition, a splenic T-cell population from L. donovani-infected B10.D2 mice suppressed the proliferation in vitro of parasite antigen-stimulated lymphocytes of irradiation-cured B10.D2 mice. Suppressor T cells were not demonstrable in the spleens of spontaneously cured C57B1/10 mice. Splenic lymphocytes from infected B10.D2 mice were deficient in the production of macrophage-activating factor (MAF) upon stimulation by L. donovani antigens in vitro. Deficient MAF production was specific for parasite antigen stimulation, because MAF production subsequent to concanavalin A stimulation of splenic lymphocytes from infected B10.D2 mice was not suppressed. The data suggest that a genetically based immunological defect in B10.D2 mice prevents the acquisition of effective cell-mediated immunity and subsequent elimination of L. donovani from tissue macrophages. The immunological deficit, not apparent in the curing C57B1/10, appears to be caused by the development of parasite antigen-specific suppressor T cells during the course of the disseminated leishmaniasis.     

Rai1 deficiency in mice causes learning impairment and motor dysfunction, whereas Rai1 heterozygous mice display minimal behavioral phenotypes

Smith-Magenis syndrome (SMS) is associated with an approximately 3.7 Mb common deletion in 17p11.2 and characterized by its craniofacial and neurobehavioral abnormalities. The reciprocal duplication leads to dup(17)(p11.2p11.2) associated with the Potocki-Lupski syndrome (PLS), a neurological disorder whose features include autism. Retinoic acid induced 1 (RAI1) appears to be responsible for the majority of clinical features in both SMS and PLS. Mouse models of these syndromes harboring an approximately 2 Mb chromosome engineered deletion and duplication, respectively, displayed abnormal locomotor activity and/or learning deficits. To determine the contribution of RAI1 in the neurobehavioral traits in SMS, we performed a battery of behavioral tests on Rai1 mutant mice and the Df(11)17-1/+ mice that have a small deletion of approximately 590 kb. The mice with the small deletion were hypoactive like the large deletion mice and they also showed learning deficits. The Rai1+/- mice exhibited normal locomotor activity. However, they had an abnormal electroencephalogram with overt seizure observed in a subset of mice. The few surviving Rai1-/- mice displayed more severe neurobehavioral abnormalities including hind limb clasping, overt seizures, motor impairment and context- and tone-dependant learning deficits. X-gal staining of the Rai1+/- mice suggests that Rai1 is predominantly expressed in neurons of the hippocampus and the cerebellum. Our results suggest that Rai1 is a critical gene in the central nervous system functioning in a dosage sensitive manner and that the neurobehavioral phenotype is modified by regulator(s) in the approximately 590 kb genomic interval, wherein the major modifier affecting the craniofacial penetrance resides.     

Myeloperoxidase deficiency. Increased sensitivity for immunocytochemical compared to cytochemical detection of enzyme

The discovery of hereditary deficiency of myeloperoxidase (MPO) in neutrophils and monocytes of affected individuals has been based on the absence of cytochemical staining in these peripheral blood cells. We report that an immunocytochemical method shows more sensitivity than either the benzidine or 4-chloro-1-naphthol cytochemical methods. In MPO-deficient subjects, immunocytochemistry detects a marked decrease, but not absence, of MPO.     

Case of partial trisomy 9p and partial trisomy 14q resulting from a maternal translocation: overlapping manifestations of characteristic phenotypes.

We report on a female infant with partial trisomy 9p (pter-->p13) and partial trisomy 14q (pter-->q22) resulting from a 3:1 segregation of a maternal reciprocal translocation (9;14)(p13;q22). Both trisomy 9p and partial trisomy 14q have been described as recognized phenotypes with characteristic patterns of anomalies. This patient appears to be the first reported with a partial duplication of both 9p and 14q resulting in an overlapping phenotype including minor facial anomalies, cleft palate, and hand-foot anomalies. However, the facial findings were more pronounced than commonly observed in cases with only one or the other duplicated chromosome regions, resulting in a distinctive appearance.     

Cytoplasmic genetics of mammalian cells: Conditional sensitivity to mitochondrial inhibitors and isolation of new mutant phenotypes

We report here that glucose, as a carbon source, and pyruvate are required for the phenotypic expression of cytoplasmically transmitted chlor-amphenicol-resistance (CAP-R) mutations, recovery of CAP-R mutants, and continuous growth in the presence of oligomycin or antimycin. We assume that glucose supplies additional energy when mitochondrial respiration is diminished and that pyruvate provides intermediates when the Krebs cycle is inhibited. Thus, the requirement for pyruvate is fully satisfied by an exogenous source of purines, and partially by -ketoglutarate or a pyrimidine source. Based upon these findings, we have obtained two types of mutations affecting mitochondrial function—oligomycin resistance and pyruvate-independent expression of chloramphenicol resistance. Both are cytoplasmically transmitted and provide new markers for a genetic analysis of mitochondrial biogenesis.This paper is dedicated to the memory of Boris Ephrussi, whose pioneering work in gene expression, mitochondrial biogenesis, and somatic cell genetics has been a continuing inspiration and guide to both of us. Ruth Sager further expresses her indebtedness for the intellectual companionship and moral support that Boris provided so generously in the dark dawn of cytoplasmic inheritance.     

Reduction of contact sensitivity reactions to oxazolone in mite-infested mice.

Oxazolone-sensitized mite-infested (SWR-M) and mite-free (SWR-J) mice were challenged with oxazolone on the skin of the neck and shoulder. The migration of radioactively labeled cells to the site of contact sensitivity reaction to oxazolone was significantly less in SWR-M than in SWR-J mice. Serum obtained from SWR-M mice suppressed the extravasation of cells into the skin site of SWR-J mice challenged with oxazolone. The decrease in cellular influx in SWR-M mice occurred in areas of mite infestation (skin of neck and shoulder) as well as in areas not infested with mites (the ears). SWR-M mice also gave evidence of enhanced vascular permeability. A possible role for histamine in the inhibition of contact sensitivity in mite-infested mice is discussed.     

Susceptibility to Leishmania major infection in mice: multiple loci and heterogeneity of immunopathological phenotypes

Susceptibility as opposed to resistance of mouse strains (e.g., BALB/c vs C57BL/6) to Leishmania major has been attributed to a defective Th1 and a predominant Th2-response, resulting in increased IL-4 and IgE production, and decreased interferon gamma (IFN gamma) production, macrophage activation and elimination of parasites. Here we report dissection of genetic and functional aspects of susceptibility to leishmaniasis using two contrasting inbred strains BALB/cHeA (susceptible) and STS/A (resistant) and a resistant Recombinant Congenic (RC) Strain, CcS-5/Dem, which carries a random set of 12.5% of genes from the strain STS and 87.5% genes from the susceptible strain BALB/c. Linkage analysis of F2 hybrids between the resistant RC strain CcS-5 and the susceptible strain BALB/c revealed five loci affecting the response to the infection, each apparently associated with a different combination of pathological symptoms and immunological reactions. The correlation between Th2-type immune reactions and the disease in the F2 mice was either absent, or it was limited to mice with specific genotypes at loci on chromosomes 10 and 17. This suggests that the resistance vs susceptibility is influenced by mechanisms additional to the postulated antagonistic effects of Th1 and Th2 responses, and that the host's genotype affects the development of leishmaniasis in a complex way.     

Genotype and laboratory and clinical phenotypes of protein s deficiency

The diagnosis of thrombophilia caused by protein S deficiency remains difficult. From 2005 to 2010, we documented 135 patients with suspected hereditary protein S deficiency for whom mutational analysis of the PROS1 gene had been performed by direct double-stranded sequencing of the amplified 15 exons including splice sites. Multiplex ligation-dependent probe amplification was performed on 12 of 15 exons in cases with no mutation found but a large deletion in the PROS1 gene was suspected. Mutations were identified in 49 patients, 9 by familial screening. Altogether, 17 new and 11 previously described mutations of PROS1 were identified among the 49 patients. After the exclusion of acquired protein S deficiency due to pregnancy or hormonal contraceptives, there remained only 1 case with protein S activity levels less than 40% that could not be explained by sequence variations or deletions in the examined regions of the PROS1 gene. After the exclusion of conditions associated with acquired protein S deficiency, persistently low protein S activity levels are highly indicative of a genetic alteration in PROS1. We observed a clear correlation between the laboratory phenotype and the type of mutation.     

Host protective immunity to Trichinella spiralis in mice: activation of Th cell subsets and lymphokine secretion in mice expressing different response phenotypes.

Host protective immunity to the intestinal dwelling nematode Trichinella spiralis is mediated by CD4+ mesenteric lymph node (MLN) cells during the course of intestinal infection. The present study has examined the cytokine production by T cells within the MLN of two H-2-compatible strains of mice infected with T. spiralis which differ in the speed at which they expel the parasite from the gut. For both strains of mice, in vitro stimulation of MLN cells with a protective worm antigen preparation resulted in secretion of elevated levels of interleukin-3 (IL-3), IL-4, IL-5 and IL-9 compared to controls. Negligible levels of interferon-gamma (IFN-gamma) were secreted. Furthermore, a similar pattern of cytokine secretion was observed from MLN cells taken from infected mice after in vitro stimulation by T-cell mitogens. No evidence was found for a relationship between quantity of cytokine secreted and the differences in speed of parasite expulsion in the two strains of mice studied. The results support the hypothesis that protective immunity to T. spiralis infection is associated with the activation of Th2-type cells within the MLN in the relative absence of Th1-type cells.     

Altered dopamine metabolism and increased vulnerability to MPTP in mice with partial deficiency of mitochondrial complex I in dopamine neurons

A variety of observations support the hypothesis that deficiency of complex I [reduced nicotinamide-adenine dinucleotide (NADH):ubiquinone oxidoreductase] of the mitochondrial respiratory chain plays a role in the pathophysiology of Parkinson's disease (PD). However, recent data from a study using mice with knockout of the complex I subunit NADH:ubiquinone oxidoreductase iron-sulfur protein 4 (Ndufs4) has challenged this concept as these mice show degeneration of non-dopamine neurons. In addition, primary dopamine (DA) neurons derived from such mice, reported to lack complex I activity, remain sensitive to toxins believed to act through inhibition of complex I. We tissue-specifically disrupted the Ndufs4 gene in mouse heart and found an apparent severe deficiency of complex I activity in disrupted mitochondria, whereas oxidation of substrates that result in entry of electrons at the level of complex I was only mildly reduced in intact isolated heart mitochondria. Further analyses of detergent-solubilized mitochondria showed the mutant complex I to be unstable but capable of forming supercomplexes with complex I enzyme activity. The loss of Ndufs4 thus causes only a mild complex I deficiency in vivo. We proceeded to disrupt Ndufs4 in midbrain DA neurons and found no overt neurodegeneration, no loss of striatal innervation and no symptoms of Parkinsonism in tissue-specific knockout animals. However, DA homeostasis was abnormal with impaired DA release and increased levels of DA metabolites. Furthermore, Ndufs4 DA neuron knockouts were more vulnerable to the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Taken together, these findings lend in vivo support to the hypothesis that complex I deficiency can contribute to the pathophysiology of PD.     

Temperature sensitivity of the paw of the cat: a behavioural study

1. Cats were trained to respond to differences between the temperatures of the floors of two corridors of a modified T-maze for a food reward.2. The cats were able to respond to differences between warm temperatures or differences between cool temperatures in the range of 1 degrees C.3. Both warm and cool discriminations were mediated by receptors located in or near the footpads.4. The paw of the cat thus appears to be more sensitive to temperature changes than was believed previously, and its temperature sensitivity may be comparable to that of the hand of the primate.     

Activated partial thromboplastin time reagent sensitivity to the presence of the lupus anticoagulant.

The lupus anticoagulant (LA) is an acquired abnormality that is associated with a prolonged activated partial thromboplastin time (aPTT). It is one of the most frequent coagulation abnormalities seen in the routine clinical laboratory. The sensitivity of various commercial aPTT reagents varies in their ability to detect the LA. We undertook this evaluation by using a single coagulation instrument to determine the sensitivity of five different commercial aPTT reagents to the presence of the LA. We evaluated 23 patients with known LA using five different reagents, two of which were marketed as having enhanced LA sensitivity. All samples and testing were performed under the same conditions in a timely manner. Based on these data, essentially all of the commercial reagents that were tested could detect patients with known LA by at least minimally prolonging the aPTT. Some reagents were slightly better than others in their ability to detect the LA. For most hospitals, the detection of the LA is not the highest priority for the use of the aPTT assay. In most cases, heparin anticoagulation monitoring is the most common use of the aPTT assay. Since all five reagents are sensitive to the LA, then the best overall reagent will be the one with the best sensitivity to the most important need for the laboratory (usually heparin monitoring). Therefore, a reagent should be chosen based on the primary monitoring requirements of the aPTT assay, and greater than 90% of the patients with the LA will be detected.     

Further contribution to the description of phenotypes associated with partial 4q duplication

We report on a 15-year-old girl with a previously undescribed de novo duplication of segment 4q13.1→q22.2. The origin of the extrachromosomal material on 4q was unequivocally established by fluorescent in situ hybridization with a chromosome 4 painting probe. Clinical manifestations included moderate mental retardation, destructive behavior, and minor physical anomalies. An analysis of the literature on partial 4q trisomy led us to identify a region comprising bands 4q22-q23, which may be involved in the development of the acrorenal field. © 1995 Wiley-Liss, Inc.     

Increased sensitivity of Corynebacterium parvum-treated mice to toxic effects of indomethacin and lipopolysaccharide.

Female BALB/c and C3H/HeJ mice develop increased sensitivity to the toxic effects of indomethacin after injection of nonviable Corynebacterium parvum. The increased sensitivity developed within 4 days of intraperitoneal injection of the organisms and started to resolve 14 days after injection. The development of increased sensitivity was dependent on the quantity of organisms injected and the concentration of indomethacin utilized. The effect was not observed when C. parvum-treated animals were injected with aspirin. C. parvum-treated BALB/c mice also developed increased sensitivity to E. coli lipopolysaccharide (LPS). Although increased sensitivity to LPS and indomethacin paralleled each other in BALB/c mice, the experiments with the LPS-resistant C3H/HeJ mice indicated that the two phenomena could be separated. The pyridine extract residue of C. parvum was as effective as C. parvum whole cells in inducing indomethacin and LPS sensitivity. Therefore, activation of the reticuloendothelial system is probably a critical element in the induction of sensitivity to these agents.     

Insulin binding and insulin sensitivity in isolated growth hormone deficiency.

125I-insulin binding to monocytes was examined in five children and one adult with isolated growth hormone deficiency before and after three to 12 weeks of growth hormone treatment, and in eight controls. Before treatment, mean plasma glucose was 15 mg per deciliter below controls, and plasma insulin was reduced by 40 per cent. Insulin binding to monocytes was 70 per cent greater than controls (P less than 0.005). Insulin-mediated glucose uptake (determined in the adult patient) was 25 per cent greater than mean control levels. After treatment, plasma glucose rose to control levels, plasma insulin increased to 75 per cent above controls (P less than 0.01), and insulin binding fell to 50 per cent below controls (P less than 0.01). Insulin-mediated glucose uptake fell to 30 per cent below the mean control rate. Insulin binding increases in growth hormone deficiency and falls after treatment. These changes may contribute to alterations in insulin sensitivity accompanying altered growth hormone availability.     

Inborn errors of immunity underlying a susceptibility to pyogenic infections: from innate immune system deficiency to complex phenotypes

BackgroundPyogenic bacteria are associated with a wide range of clinical manifestations, ranging from common and relatively mild respiratory and cutaneous infections to life-threatening localized or systemic infections, such as sepsis and profound abscesses. Despite vaccination and the widespread use of effective antibiotic treatment, severe infection is still observed in a subset of affected patients.ObjectivesWe aim to summarize the available data regarding inborn errors of immunity that result in a high risk of severe pyogenic infections.SourcesCase series, as well as review and original articles on human genetic susceptibility to pyogenic infections were examined.ContentWe review host-associated factors resulting in inborn errors of immunity and leading to a susceptibility to pyogenic infections, including deficiency in major components of the immune system (e.g., neutrophils, complement, immunoglobulin, and spleen function) and novel monogenic disorders resulting in specific susceptibility to pyogenic infection. Specifically, innate immune system deficiency involving toll-like receptors and associated signaling typically predispose to a narrow spectrum of bacterial diseases in otherwise healthy people, making a diagnosis more difficult to suspect and confirm. More complex syndromes, such as hyper IgE syndrome, are associated with a high risk of pyogenic infections due to an impairment of the interleukin-6 or -17 signaling, demonstrating the pivotal role of these pathways in controlling bacterial infections.ImplicationsIn clinical practice, awareness of such conditions is essential, especially in the pediatric setting, to avoid a potentially fatal diagnostic delay, set the most proper and prompt treatment, and ensure prevention of severe complications.     

Visceral leishmaniasis in congenic mice of susceptible and resistant phenotypes: immunosuppression by adherent spleen cells.

Visceral leishmaniasis is one of several parasitic diseases of humans characterized by immune suppression. A murine model of disseminated leishmaniasis utilizing inbred strains of specific genetic constitution was used to study the mechanisms of immunosuppression elicited during the course of infection. Resistant (Lshr) and susceptible (Lshs) strains of mice were challenged with amastigotes of Leishmania donovani and evaluated as to immune status at intervals between 2 and 40 weeks after challenge. The proliferative responses of splenic lymphocytes to T-cell mitogens, a B-cell mitogen, and parasite antigens were measured to evaluate the relative immune status of parasitized mice and noninfected control mice. Lymphocytes from resistant C3Heb/FeJ (C3H) mice responded normally to concanavalin A and phytohemagglutinin throughout the course of infection. Parasite antigen responses appeared 2 weeks after challenge of C3H mice and remained vigorous for periods up to 6 months. In contrast, immune suppression during infection was profound in both the curing (C57B1/10) and noncuring (B10.D2) phenotypes of Lshs congenic mice. Both Lshs strains developed severe infection as evidenced by high parasite burdens in the liver and spleen 4 to 5 weeks after challenge; splenic lymphocytes taken from these mice between 2 and 8 weeks became increasingly unresponsive to the T-cell mitogens as well as to parasite antigens. The noncuring B10.D2 mice which suffered chronic infection continued to be suppressed for as long as 40 weeks. C57B1/10 (curing) mice, in contrast, cleared infection between 12 and 16 weeks. After spontaneous recovery or elimination of parasites by antimonial drug therapy, the response of spleen cells to T-cell mitogens or parasite antigens were restored to normal. The spleen cells from the Lshs strains of mice obtained during the height of infection suppressed the proliferative responses of spleen cells from their uninfected counterparts upon cocultivation in vitro. Removal of adherent cells from the suppressive spleen cell populations restored normal mitogen responses. On the basis of adherence characteristics, phagocytosis, and morphology, the suppressor was identified as a macrophage population which appears to be responsible for a nonspecific immunosuppression of Lshs mice with significant parasite burdens of L. donovani.