Heterophile antigens of organisms causing particularly dangerous infections and their action on human intestinal tissues

To detect heterophile antigens similar to those of human small intestinal tissue in organisms responsible for particularly dangerous infections, strains varying in their degree of virulence were used:Vibrio cholerae Vibrio El Tor, vibrios of Heiberg's VI group, water-inhabiting and nonagglutinating vibrios, and virulent and avirulent strain ofPasteurella pestis. Heterophile antigens were detected in strains ofV. cholrae, V. El Tor, nonagglutinating vibrios with the ability to cause cholera, and in the virulent strain,P. pestis 232. No reaction was obtained with all the other strains tested.     

Interaction between Bdellovibrio bacteriovorus and the cytoplasmic membrane of Escherichia coli B

Adsorption ofBdellovibrio bacteriovorus (Bdv) on the surface ofEscherichia coli is accompanied by a sharp decrease in the initial rate of entry of α-methylglucoside-C¹⁴ and thiomethylgalactopyranoside-C¹⁴ into the host cell. Interaction between the parasite andE. coli leads to the rapid departure of previously accumulated labeled glucosides and β-galactosides from the bacteria. Meanwhile the ATP content inE. coli falls sharply. Adsorption of Bdv onE. coli spheroplasts was established as a fact. The possible mechanisms of interaction between Bdv and the host cell at the cytoplasmic membrane level are discussed.     

Blocking action of snake venom polypeptides on cholinergic mechanisms of the leech dorsal muscle

The blocking action of α-polypeptides isolated from the venom ofBungarus multicinctus andNaja naja siamensis was investigated in experiments on the isolated dorsal muscle of the leech. These neurotoxins (NTs), in a concentration of 1×10^?5 g/ml, did not block responses to monoquaternary cholinomimetics (acetylcholine, carbachol, nicotine, monocholine ester of succinic acid). The ability of NT to block responses to biquaternary cholinomimetics depended on the length of their molecule. Only responses to dicholine esters of malonic, succinic and glutaric acids were blocked by NT. Dicholine esters of adipic, pimelic, suberic, azelaic, and sebacic acids retained the whole of their activity after treatment of the leech muscle with NT. The possible causes of the selective action of NT are discussed.     

Action of the mycotoxin of Fusarium sporotrichiella v. sporotrichioides on lysosomal membranes

The effect of the mycotoxin ofFusarium sporotrichiella v. sporotrichioides (sporofusarin) was studied in vitro on the total and nonsedimenting activity of eight lysosomal enzymes: acid ribonuclease, aryl sulfatases A and B, β-glucuronidase, α-and β-galactosidases, β-glucosidase, β-acetylglucosaminidase, and α-mannosidase. Incubation of a suspension of rat liver lysosomes with an aqueous solution of sporofusarin led to inhibition of the total activity of the membrane-bound lysosomal enzyme β-glucosidase. In a dose of only 1.6×10^?5 M sporofusarin caused a significant increase in the nonsedimenting activity of nearly all the enzymes; in a concentration of 1.6×10^?3 M most of the enzymes of the lysosomal matrix (β-glucuronidase, β-galactosidase, aryl sulfatases A and B) were liberated almost completely into the supernatant, and nearly all the β-glucosidase also was liberated. It is postulated that damage to the subcellular membranes is an important component of the toxic action of sporofusarin.     

The complete nucleotide sequence of a novel partitivirus isolated from the plant pathogenic fungus Verticillium albo-atrum

We have characterized the bisegmented genome of a novel double-stranded RNA (dsRNA) virus isolated from the plant pathogenic fungus Verticillium albo-atrum. We determined that its larger segment (dsRNA1) was 1747 base pairs in length and potentially encoded an RNA-dependent RNA polymerase of 539 amino acids, whereas the smaller segment (dsRNA2) was 1517 base pairs long and was predicted to encode a capsid protein of 435 amino acids. Homology searches and phylogenetic analysis confirmed that, as expected from its dsRNA banding profile, the identified virus was a new member of the family Partitiviridae, and we have therefore designated it V. a lbo- a trum partitivirus 1 (VaaPV1). This is the first report of a mycovirus identified in V. albo-atrum.     

Differences in activity of peritoneal phagocytes in female and male SWR/J mice

The object of the investigation was to compare macrophagal and neutrophilic reactions in female and male SWR/J mice. Differences in the activity of the peritoneal phagocytes of the females and males relative to a pathogenic strain ofSalmonella typhimurium were found. The results indicate that when animals are chosen for experimental purposes and the results of investigations assessed consideration must be paid to sex, for the intensity of immune reactions differs in males and females and this affects the experimental results.     

Intact IFN-γR1 Expression and Function Distinguishes Langerhans Cell Histiocytosis From Mendelian Susceptibility to Mycobacterial Disease

Purpose

Poly-ostotic Langerhans Cell Histiocytosis (LCH) can be difficult to distinguish clinically and histologically from disseminated infection in manifesting specific subtypes of Mendelian Susceptibility to Mycobacterial Disease (MSMD). In MSMD-patients, dominant negative germline mutations in the IFN-γR1 gene, in particular in exon 6, lead to autosomal dominant IFN-γ receptor 1 deficiency (ADIFNGR1) and can mimic LCH. We hypothesized that similar defects might underlie the pathogenesis of LCH.

Methods

IFN-γR1 expression was immunohistochemically determined at disease onset in biopsies from 11 LCH-patients and four ADIFNGR1-patients. IFN-γR1 function was analyzed in 18 LCH-patients and 13 healthy controls by assessing the IFN-γ-induced upregulation of Fc-gamma-receptor I (FcγRI) expression on monocytes. Pro-inflammatory cytokine production was measured after stimulation of whole blood with LPS and IFN-γ. Exon 6 of the IFN-γR1 gene was sequenced in 67 LCH-patients to determine whether mutations were present.

Results

IFN-γR1 expression was high in three LCH-affected biopsies, similar to ADIFNGR1-affected biopsies, but varied from negative to moderate in eight other LCH-affected biopsies. No functional differences in IFN-γ signaling were detected between LCH-patients with active or non-active disease and healthy controls. No germline mutations in exon 6 of the IFN-γR1 gene were detected in any of the 67 LCH-patients.

Conclusions

In contrast to ADIFNGR1-patients, IFN-γ signaling is fully functional in LCH-patients. Either performed before, during or after treatment, these non-invasive functional assays can distinguish LCH-patients from ADIFNGR1-patients and thereby facilitate correct therapy regimens for patients with recurrent osteolytic lesions.     

Linkage study of fibrinogen levels: the Strong Heart Family Study

Background

A common SNP upstream of the INSIG2 gene, rs7566605 (g.-10,1025G>C, Chr2:118,552,255, NT_022135.15), was reported to be associated with obesity (Body Mass Index, [BMI]) in a genome-wide association scan using the Framingham Heart Study but has not been reproduced in other cohorts. As BMI is a relatively insensitive measure of adiposity that is subject to many confounding variables, we sought to determine the relationship between the INSIG2 SNP and subcutaneous fat volumes measured by MRI in a young adult population.

Methods

We genotyped the INSIG2 SNP rs7566605 in college-aged population enrolled in a controlled resistance-training program, (the Functional Polymorphism Associated with Human Muscle Size and Strength, FAMuSS cohort, n = 752 volunteers 18–40 yrs). In this longitudinal study, we examined the effect of the INSIG2 polymorphism on subcutaneous fat and muscle volumes of the upper arm measured by magnetic resonance imaging (MRI) before and after 12 wks of resistance training. Gene/phenotype associations were tested using an analysis of covariance model with age and weight as covariates. Further, the % variation in each phenotype attributable to genotype was determined using hierarchical models and tested with a likelihood ratio test.

Results

Women with a copy of the C allele had higher levels of baseline subcutaneous fat (GG: n = 139; 243473 ± 5713 mm³ vs. GC/CC: n = 181; 268521 ± 5003 mm³; p = 0.0011); but men did not show any such association. Men homozygous for the G ancestral allele showed a loss of subcutaneous fat, while those with one or two copies of the C allele gained a greater percentage of subcutaneous fat with resistance training (GG: n = 103; 1.02% ± 1.74% vs. GC/CC: n = 93; 6.39% ± 1.82%; p = 0.035).

Conclusion

Our results show that the INSIG2 rs7566605 polymorphism underlies variation in subcutaneous adiposity in young adult women and suppresses the positive effects of resistance training on men. This supports and extends the original finding that there is an association between measures of obesity and INSIG2 rs7566605 and further implicates this polymorphism in fat regulation.     

Three nights of sleep deprivation does not alter thermal strain during exercise in the heat

Purpose

Individuals exposed to total sleep deprivation may experience an increased risk of impaired thermoregulation and physiological strain during prolonged physical activity in the heat. However, little is known of the impact of more relevant partial sleep deprivation (PSD). This randomized counterbalanced study investigated the effect of PSD on thermal strain during an exercise-heat stress.

Methods

Ten healthy individuals performed two stress tests (45 min running, 70 % ${\dot{V}\text{O}}_{2\hbox{max} }$ V · O 2 max 33 °C, 40 % RH). Each trial followed three nights of controlled sleep: normal [479 (SD 2) min sleep night^?1; Norm] and PSD [116 (SD 4) min sleep night^?1]. Energy balance and hydration state were controlled throughout the trials. Rectal temperatures (T _re), mean skin temperature ( $\bar{T}_{\text{sk}}$ T ¯ sk ), heart rate (HR), RPE, and thermal sensations (TS) were measured at regular intervals during each heat stress trial.

Results

There was a significant main effect of time (P < 0.05) for all of these variables. However, no differences (P > 0.05) were observed between PSD and Norm, respectively, for T _re [39.0 (0.5) vs. 39.1 (0.5)  °C], $\bar{T}_{\text{sk}}$ T ¯ sk , [36.1 (0.6) vs. 36.0 (0.7)  °C] and HR [181 (13) vs. 182 (13) beats min^?1)] at the end of exercise-heat stress. There were no differences (P > 0.05) in $\bar{T}_{\text{sk}}$ T ¯ sk , PSI, RPE, TS and whole-body sweat rate between PSD versus Norm.

Conclusion

Since greater physiological strain during exercise-heat stress did not follow three nights of PSD, it appears that sleep loss may have minimal impact upon thermal strain during exercise in the heat, at least as evaluated within this experiment.     

Reaction of rat embryonic tissues to mechanical injury and infection with Staphlococcus aureus (strain 209)

Healing of skin wounds and the tissue reaction to intrauterine injection ofStaphylococcus aureus (strain 209) were studied in experiments on albino rat embryos. With a horizontal incision, an orthotonic position of the fetus and retraction of the skeletal muscles prevented contraction of the wound and epithelization of its surface. With a vertical incision the wound edges approximated and healing took place without the formation of granulation tissue by epithelization of the wound surface 2 days after the operation. The embryo responded to injection of the pathogenic staphylococcus by a uniform local reaction with predominance of degenerative changes and accumulation of histiocyte-like cells close to some of the colonies. No exudative inflammatory reaction was present either to trauma or to injection of the staphylococcus at all stages of intrauterine life.     

Effect of cyclic AMP on the development of sea urchin embryos

The effect of cyclic adenosine-3′,5′-phosphate (cyclic AMP) on cleavage of early embryos of the sea urchinStrongylocentrotus intermedius was studied. A nontoxic concentration of cyclic AMP was found to have a protective action against the embryotoxic effect of serotonin antagonists NK-122 and chlorpromazine, as well as a protective action against the effect of a toxic concentration of prostaglandin F_2α; prostaglandin F_2α also had a protective action against the effect of a toxic concentration of cyclic AMP.     

Determination of the activity of choleragen on tadpoles

A method of titration of choleragen in tadpoles ofRana temporaria is suggested. Unlike in methods known hitherto, the animals are kept (10 at a time) in vessels with water containing serial dilutions of choleragen. The degree of activity of the choleragen is determined from the percentage of dying animals. The dilution of cholergen causing death of 50% of tadpoles after 24 h was taken as the unit of activity. The method is simple, accurate, easily reproducible, and economical in use.     

Fate of toxoplasma gondii in macrophages in vitro depending on virulence of the parasites

A comparative light-optical and submicroscopic study was made of the development of strains ofToxoplasma gondii with high and low virulence in macrophages in vitro. By contrast with the active multiplication of the highly virulent strain, most toxoplasmas of the less virulent strain underwent disintegration within a few hours after penetrating into the cell, so that as a result, 24–48 h after infection, they were completely digested. Submicroscopic investigation revealed no significant morphological changes in the macrophages infected by the less virulent toxoplasmas, whereas the nuclei of macrophages infected with highly virulent toxoplasma were considerably altered. Disintegration of the parasites within the phagosome is accompanied by gradual transformation, initially of the double or triple membrane of the cyst containing the parasite into a single membrane and disappearance of the accessory layer from the mitochondria and structures of the endoplasmic reticulum surrounding the membrane of a cyst.     

Changes in sensitivity of developing sea urchin embryos to prostaglandin F2α and to cyclic AMP

The developing ova of the sea urchinStrongylocentrotus intermedius, at different stages of the first mitotic cycles, vary in their sensitivity to toxic concentrations of prostaglandin F_2α and cyclic 3′,5′-AMP. Differences in sensitivity to each of these substances follow a similar and regular pattern and depend on the time elapsing after the preceding division. Two periods of increased sensitivity of the ova were found: the first, 20 min after completion of each division, to both substances and the second, after 40 min to cyclic AMP and after 50 min to prostaglandin.     

Investigation of the action of sporofusarin on cell membranes of the isolated perfused liver

The effect of sporofusarin (a myoctoxin produced byFusarium sporotrichiellav. sporotrichioides) on the functional activity and permeability of cell membranes of the isolated perfused rat liver was studied. Sporofusarin in a final concentration of 5.9·10^?5 M was found to reduce the rate of bile formation, urea synthesis, and oxygen consumption and also to cause an earlier and severe disturbance of permeability of the lysosomal and plasma membranes of the hepatocytes (an increase in activity of the enzymes β-acetylglucosaminidase, β-glucuronidase, arylsulfatases A and B, and β-galactosidase in the supernatant of a liver homogenate and in the perfusion fluid). The depression of liver function by sporofusarin is considered to be the result of damage to the membraneous structures of the cell and, in particular, of the lysosomes.     

Electrical responses of Retzius cells of the leech to inhibition of active ionic transport by ouabain

The effect of the cardiac glycoside ouabain in a concentration of 10^?4 M on the electrical properties of the Retzius cells in a segmental ganglion of the central nervous system ofHirudo medicinalis was studied by a microelectrode technique. The first phase of the response is depolarization of the cell membrane by 4–11 mV and an increase in the frequency of spontaneous activity with no change in the electrical resistance, both of which develop after about 1 min. The second phase, taking 2–10 min to complete, is characterized by the cessation of spike activity and by a decrease in the resistance of the membrane, and also by the total disappearance of electrical transmission such as is normally observed between the two cells of the ganglion. The response is reversible by prolonged rinsing to remove the ouabain.     

Increases in \dot{V} O2max with “live high–train low” altitude training: role of ventilatory acclimatization

The purpose of this study was to estimate the percentage of the increase in whole body maximal oxygen consumption ( $ \dot{V} $ O_2max) that is accounted for by increased respiratory muscle oxygen uptake after altitude training. Six elite male distance runners ( $ \dot{V} $ O_2max = 70.6 ± 4.5 ml kg^?1 min^?1) and one elite female distance runner ( $ \dot{V} $ O_2max = 64.7 ml kg^?1 min^?1) completed a 28-day “live high–train low” training intervention (living elevation, 2,150 m). Before and after altitude training, subjects ran at three submaximal speeds, and during a separate session, performed a graded exercise test to exhaustion. A regression equation derived from published data was used to estimate respiratory muscle $ \dot{V} $ O₂ ( $ \dot{V} $ O_2RM) using our ventilation ( $ \dot{V} $ _E) values. $ \dot{V} $ O_2RM was also estimated retrospectively from a larger group of distance runners (n = 22). $ \dot{V} $ O_2max significantly (p < 0.05) increased from pre- to post-altitude (196 ± 59 ml min^?1), while $ \dot{V} $ _E at $ \dot{V} $ O_2max also significantly (p < 0.05) increased (13.3 ± 5.3 l min^?1). The estimated $ \dot{V} $ O_2RM contributed 37 % of Δ $ \dot{V} $ O_2max. The retrospective group also saw a significant increase in $ \dot{V} $ O_2max from pre- to post-altitude (201 ± 36 ml min^?1), along with a 10.8 ± 2.1 l min^?1 increase in $ \dot{V} $ _E, thus requiring an estimated 27 % of Δ $ \dot{V} $ O_2max. Our data suggest that a substantial portion of the improvement in $ \dot{V} $ O_2max with chronic altitude training goes to fuel the respiratory muscles as opposed to the musculature which directly contributes to locomotion. Consequently, the time-course of decay in ventilatory acclimatization following return to sea-level may have an impact on competitive performance.     

Cardiac myosin heavy chains in mice treated with NG-nitro-l-arginine methyl ester and thyroxine

The aim of this study was to evaluate the effect of N^G-nitro-l-arginine methyl ester and thyroxine on the distribution of cardiac myosin heavy chains in mice. Myocardial hypertrophy was induced in mice by intraperitoneal injection with l-thyroxine and oral administration of N^G-nitro-l-arginine methyl ester (l-NAME). Mice were randomly allocated into five groups: control, high and low doses of thyroxine and L-NAME. Heart weight divided by body weight was calculated and used as indicator for cardiac hypertrophy. Myosin heavy chains (MHCs) were separated using 4 % polyacrylamide gel electrophoresis. Hypertrophy was induced in mice treated with thyroxine and a high dose of l-NAME and was accompanied by a shift toward α-MHC in thyroxine-treated mice and β-MHC in l-NAME-treated mice. There was no difference with respect to MHC between a low dose of l-NAME and a high dose; however, low doses of l-NAME did not result in cardiac hypertrophy. In conclusion, l-NAME treatment changes the MHC distribution from α- toward β-MHC and this transition in the MHCs occurs before heart hypertrophy. Further investigations are needed to determine whether l-NAME treatment causes this transition via a direct or indirect effect on the heart muscles.     

Skeletal muscle \dot{V} {\text{O}_2} kinetics from cardio-pulmonary measurements: assessing distortions through O2 transport by means of stochastic work-rate signals and circulatory modelling

During non-steady-state exercise, dynamic changes in pulmonary oxygen uptake ( $\dot{V} {\text{O}_{\text{2pulm}}}$ ) are dissociated from skeletal muscle $ \dot{V} {\text{O}_2}$ ( $\dot{V} {\text{O}_{\text{2musc}}}$ ) by changes in lung and venous O₂ concentrations (CvO₂), and the dynamics and distribution of cardiac output (CO) between active muscle and remaining tissues ( $ \dot{Q}_{\text{rem}}$ ). Algorithms can compensate for fluctuations in lung O₂ stores, but the influences of CO and CvO₂ kinetics complicate estimation of $\dot{V} {\text{O}_{\text{2musc}}}$ from cardio-pulmonary measurements. We developed an algorithm to estimate $\dot{V} {\text{O}_{\text{2musc}}}$ kinetics from $\dot{V} {\text{O}_{\text{2pulm}}}$ and heart rate (HR) during exercise. 17 healthy volunteers (28 ± 7 years; 71 ± 12 kg; 7 females) performed incremental exercise using recumbent cycle ergometry ( $\dot{V} {\text{O}_{\text{2peak}}}$ 52 ± 8 ml min^?1 kg^?1). Participants completed a pseudo-random binary sequence (PRBS) test between 30 and 80 W. $\dot{V} {\text{O}_{\text{2pulm}}}$ and HR were measured, and CO was estimated from HR changes and steady-state stroke volume. $\dot{V} {\text{O}_{\text{2musc}}}$ was derived from a circulatory model and time series analyses, by solving for the unique combination of venous volume and the perfusion of non-exercising tissues that provided close to mono-exponential $\dot{V} {\text{O}_{\text{2musc}}}$ kinetics. Independent simulations showed that this approach recovered the $\dot{V} {\text{O}_{\text{2musc}}}$ time constant (τ) to within 7 % (R ² = 0.976). Estimates during PRBS were venous volume 2.96 ± 0.54 L; $ \dot{Q}_{\text{rem}}$ 3.63 ± 1.61 L min^?1; τHR 27 ± 11 s; τ $\dot{V} {\text{O}_{\text{2musc}}}$ 33 ± 8 s; τ $\dot{V} {\text{O}_{\text{2pulm}}}$ 43 ± 14 s; $\dot{V} {\text{O}_{\text{2pulm}}}$ time delay 19 ± 8 s. The combination of stochastic test signals, time series analyses, and a circulatory model permitted non-invasive estimates of $\dot{V} {\text{O}_{\text{2musc}}}$ kinetics. Large kinetic dissociations exist between muscular and pulmonary $\dot{V} {\text{O}_{\text{2}}}$ during rapid exercise transients.