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At least 127 records · Page 7Linked to original sources
PubMed1987

[Difference in the maturation of the three-domain vasopressin precursor in the guinea-pig and rat: identification of a neurophysin-copeptin fragment in the guinea pig].

Vasopressin, MSEL-neurophysin and copeptin have been isolated from guinea pig and rat neurophypophyses and their amino acid sequences have been determined. Whereas in rat processing of the three-domain precursor is complete, in the guinea pig a 132-residue fragment including MSEL-neurophysin and copeptin linked by an arginine residue has been characterized. This incomplete maturation (20% of the precursor) could be due to a deletion of an acidic residue in guinea pig copeptin when compared with other mammalian copeptins.

Amino Acid Sequence↗
PubMedDate not supplied

The effects of acetylcholine and catecholamines on post-rest phenomena in rabbit and guinea-pig atria and on accompanying shifts of 45Ca in guinea-pig atrial muscle.

We studied the pattern of post-rest activation and shifts of 45Ca in the isolated mammalian atrial muscle. The first contraction evoked in the rabbit and guinea-pig atrial muscle after 10 min rest was several times stronger than the steady-state beats at a rate of 60/min. Contractile force (CF) declined to 20-50% of control during the next 1-3 beats and recovered to the pre-rest level upon subsequent stimulation. The post-rest beats were negligibly affected by noradrenaline (NA), isoproterenol (IS) acetylcholine (ACh), carbachol (CCh) and Ni, whereas the steady-state beats were readily affected by all these drugs or ions. Post-rest potentiation was completely inhibited by caffeine in a concentration of 10 mM. The guinea-pig atria, equilibrated for 60 min in 45Ca containing solution and stimulated at a rate of 60/min, contained 4.47 +/- 0.16 mmol 45Ca/kg wet weight (w.w.). Ten min of rest resulted in a drop of this content to 3.52 +/- 0.13 mmol/kg w.w. despite the continued presence of 45Ca in the superfusing solution. Three initial post-rest beats resulted in further drop of the content of 45Ca to 2.62 +/- 0.14 mmol/kg w.w. Continued post-rest stimulation resulted in a recovery of the pre-rest 45Ca content. This recovery was inhibited by ACh and CCh. Both drugs inhibited 45Ca loss during the initial 3 beats. Neither this loss nor recovery were affected by IS. It is concluded that calcium (Ca) fraction described in the previous papers [11, 15] as Ca2 in the guinea-pig ventricular muscle plays an important role in the force-frequency relations also in the atrial muscle. However, unlike in ventricular muscle only about half of it is released from the cells upon rest whereas the remaining Ca is taken up by the release compartment and used to activate the strong post-rest contraction. It is thereafter extruded from the cells which results in severe depletion of intracellular Ca stores. Fraction Ca2 is re-accumulated during the post-rest stimulation resulting in recovery of the contractile force.

Acetylcholine↗
PubMed1976

Formed blood elements in peritoneal effusion and the macrophage migration inhibition test in healthy guinea pigs and in guinea pigs with experimental allergic encephalomyelitis.

An attempt was made to correlate the percentages of macrophages, lymphocytes and granulocytes in the peritoneal effusion in healthy guinea pigs and guinea pigs with experimental allergic encephalomyelitis (EAE), with the macrophage migration inhibition (MMI) test. Varying percentages of the cells had no influence on values of MMI. Similarly, in guinea pigs with EAE, percentages of formed elements in peritoneal effusion were not correlated with intensity of MMI or with histopathologic lesions in the brain and spinal cord. It is suggested that the observed differences are due to individual immunologic responsiveness of animals and, probably, to other hitherto unknown mechanisms.

Animals↗
PubMed1976

Mutant lines of guinea pig L2C leukemia. III. The reaction of an alloantiserum detecting idiotypic determinants on a clonally derived guinea pig B cell leukemia with IgM and Ia molecules.

An alloantiserum was prepared in a strain 13 guinea pig against the GH line of the strain 2 guinea pig L2C leukemia. This serum contained antibodies to both IgM and Ia molecules. After absorption with normal spleen cells from a strain 2 guinea pig, this antiserum no longer reacted with strain 2 cells, but detected idiotypes on the IgM molecules of the L2C leukemia. These idiotypes were on the same IgM molecules detected by a xenogeneic sheep anti-L2C Fab mu antiserum. As assayed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the idiotype-bearing IgM molecules were synthesized by the cell, composed of normal sized mu and light chains, appeared on the cell surface as monomeric IgM, and were the only immunoglobulin molecules present on the cell. Although the alloantiserum potentially contained antibodies to unique Ia idiotypic determinants, none were found. Furthermore, the anti-IgM idiotype antisera did not react with any Ia-like molecules.

Animals↗
PubMed1975

Mechanisms of protective immunity in experimental cutaneous leishmaniasis of the guinea-pig. II. Selective destruction of different Leishmania species in activated guinea-pig and mouse macrophages.

Macrophages activation as the effector mechanism in destroying L. enriettii in the guinea-pig, and L. tropica in the mouse, was tested in vitro. Activated guinea-pig macrophages, with enhanced anti-Listeria capacity had no effect on the survival of intracellular L. enriettii, irrespective of the antigen used. Activated mouse macrophages, on the other hand, destroyed ingested L. enriettii within 24-48 hr but had no effect on L. tropica during the same time period. It is suggested that the pathogenicity of a Leishmania parasite in a given host depends on the ability of the parasite to survive in the host's activated macrophages. The possible mechanisms by which L. enriettii evades destruction in activated guinea-pig macrophages are discussed.

Animals↗
PubMed1994

[Experimental tuberculosis infection of guinea pigs in the necropsy room and examination of infection risk using guinea pigs with tuberculosis].

The high incidence of tuberculosis among necropsy workers is well known and several problems related to their working conditions have been pointed out. We investigated the possibility of infection with tubercle bacilli under necropsy working conditions using guinea pigs housed in a necropsy room in which about 2,000 necropsies per year were carried out. Tuberculosis infection developed in one out of five guinea pigs. In addition, we exposed five guinea pigs to tubercle bacilli and sacrificed them in a safety cabinet. The lungs, livers, and spleens were resected, flattened, and sliced finely on a cutting board. Detection of tubercle bacilli from filtered air and the surfaces of the room was attempted, however, no bacilli were cultured. The resected tuberculous lungs were intra-tracheally treated with formalin or physiological saline and the viability of the bacilli in the lung was assessed. Bacilli survived up to two hours after physiological saline injection but no viable organisms were detected after 15 minutes of formalin treatment. These findings indicate that the necropsy room workers were exposed to tuberculosis infection. As a preventive control measure, we recommend to treat tuberculous organs in the safety cabinet and to slice lungs after formalin treatment.

Air Microbiology↗
PubMed2001

Performance of West African dwarf goats fed Guinea grass-Verano stylo mixture, N-fertilized and unfertilized Guinea grass.

The supplementary values of Verano stylo in a mixed Guinea grass (Panicum maximum cv. Ntchisi)-Verano stylo (Stylosanthes hamata cv. Verano) diet from a sown grass-legume mixture and N fertilized grass were compared in West African dwarf (WAD) goats. Liveweight (LW) gain, feed intake, digestibility and N utilization were determined using 15 goats in two trials lasting for 98 days. Goats were fed Guinea grass-Verano stylo mixture (GSM), N-fertilized (NFG) and unfertilized grass (UFG). The goats were divided into three groups of five animals each and randomly allocated to the dietary treatments in a randomized complete block design. Total DM and OM intakes of the goats did not vary significantly among the forage diets and averaged 55.1 and 50.4gkg(-1)W(0.75) per day, respectively. CP intake (gkg(-1)W(0.75) per day) was highest with NFG (5.6) followed by GSM (4.8) and the UFG (3.5). Total N excreted followed the same trend as the CP intake. There was no significant difference between N-retention of GSM and NFG (28.5 and 26.7%), but goats on UFG had a negative N balance (-9.16%). Animals on GSM had significantly higher liveweight gain (31.9g per day) than those of NFG (25.1g per day) and UFG (21.9g per day) which also differed significantly. The digestibilities of total DM, OM, CP, NDF were higher with GSM than NFG or UFG. It is concluded that growing Verano stylo in mixture with Guinea grass is a better option for improving the feed quality of forage diets for goats than direct application of inorganic fertilizer at 200kgNha(-1) to the pure grass.

Journal Article↗
PubMed1982

[Structural and functional characteristics of IgG1- and IgG2-antibody subclasses in the guinea pig. 2. Production and testing of specific antisera against IgG1 and IgG2-antibody subclasses and against Fc-, Fc'- and Fab-papain fragments of IgG2-antibodies in guinea pigs].

Rabbit antisera against specifically purified guinea pig IgG1 and IgG2 antibodies and against several papain-fragments of IgG2 were produced. These antisera were made specific by absorption with purified immunoglobulin of the other subclass and assayed for monospecificity by two immunological tests. In the macrophage rosette inhibition test, only the anti-IgG2 and the anti-Fab (IgG2) sera were effective. Inhibition of the rosette formation could be obtained at dilutions up to 1:100 or higher. Attempts to induce passive cutaneous anaphylaxis in the guinea pig skin after sensibilization with homocytotropic antibodies were evidently positive only with rabbit anti-guinea pig IgG1 serum. Anti-IgG2 and anti-IgG2 Fab sera revealed a positive reaction in higher concentrated forms (1:2 or 1:5 diluted) only.

Animals↗
PubMed1989

Occasional parasitic infections of man in Papua New Guinea and Irian Jaya (New Guinea).

Most parasites of man in New Guinea are cosmopolitan species, widely distributed and highly prevalent in the island. Reports of other parasite infections are reviewed. This impoverished fauna includes anthroponotic species normally occurring at low prevalences, e.g. Isospora belli, Dientamoeba fragilis, Trichomonas hominis and a few zoonotic forms with pigs as reservoir hosts, notably Balantidium coli and Entamoeba polecki. Other zoonoses are very few and extremely rare. This may be due to the reduced placental mammal fauna. The potential for the spread of Taenia solium infection is highlighted, as is the unique zoogeographical distribution of the Strongloides species resembling S. fuelleborni. Enterobius gregorii is recorded for the first time from Papua New Guinea.

Adolescent↗
PubMed1963

PROPERTIES OF GUINEA PIG 7S ANTIBODIES. V. INHIBITION BY GUINEA PIG GAMMA-2 ANTIBODIES OF PASSIVE IMMUNE LYSIS PROVOKED BY GAMMA-2 ANTIBODIES.

Passive immune lysis of antigen-coated erythrocytes provoked in vitro by guinea pig gamma(2) antihapten antibodies in the presence of complement, is inhibited by guinea pig gamma(1) antibodies directed against the same specificity. This inhibition of the lytic effect of complement-fixing gamma(2) antibodies is presumably due to the competition for antigen by non-lytic gamma(1) antibodies.

Animals↗
PubMed1983

Effects of leukotrienes C4 and D4 on guinea-pig heart and the participation of SRS-A in the manifestations of guinea-pig cardiac anaphylaxis.

Synthetic leukotrienes C4 and D4 (LTC and LTD) were found to possess potent coronary vasoconstrictor and cardiac depressant actions on isolated guinea-pig hearts. We therefore went further to investigate the possibility that endogenously released slow-reacting substance of anaphylaxis (SRS-A) might be responsible for the coronary vasoconstriction and negative inotropism in guinea-pig cardiac anaphylaxis. Results using time-course analysis as well as the specific SRS antagonist FPL 55712 have shown that SRS-A released during cardiac anaphylaxis was unlikely to be responsible for the early and most dramatic phase of coronary vasoconstriction that usually occurred at the 2nd min after antigen challenge, but could possibly be responsible for the latter and more prolonged phase occurring between the 6th and 14th min. This is because SRS-A release was found to peak at the 4th min after antigen challenge, 2 min after vasoconstriction had already peaked. Moreover, this early component of coronary vasoconstriction could not be blocked by FPL 55712, whereas the latter component was significantly reduced by the antagonist. The negative inotropism following cardiac anaphylaxis was also found to be significantly reduced by FPL 55712, thus suggesting SRS-A involvement. However, our experiments did not show whether the two actions were direct effects of SRS-A or whether contractility failure was a consequence of coronary vasoconstriction.

Anaphylaxis↗
PubMed1975

Herpes genitalis in guinea-pigs. II. Morphological studies in female guinea-pigs infected with Herpesvirus hominis type 2.

Gross and microscopial morphological changes developing in female guinea-pigs after vaginal infection with HVH 2/Angelotti were studied. In the mucosa of the external genital tract there were inflammatory changes with formation of intra-epithelial vesicles, erosions and ulcerations. In the late stages of the infection signs of inflammatory dysplasia were also observed. The infection spread into the nervous system and produced characteristic inflammatory changes. The inflammation began as a bilateral posterior myelitis and ascended in the course of infection through the upper spinal-cord towards the brain-stem. The morphological changes were preceded by increased virus replication in the respective tissues and were correlated in time with clinical symptoms. The morphological changes seen at the site of inoculation in the external genital tract of the guinea-pig bore a certain resemblance to those seen in some cases of human infection with the same type of virus.

Animals↗
PubMed1996

Inhibition of PAF-, LPS-, and cytokine-induced granulocyte accumulation in guinea pig lung by dexamethasone: evidence that inhibition of IL-5 release is responsible for the selective inhibition of eosinophilia by glucocorticoids in guinea-pigs.

The potency of dexamethasone has been determined as an inhibitor of intratracheally administered platelet activating factor- (PAF), or interleukin (IL)-5-induced eosinophilia, and of lipopolysaccharide-(LPS), tumour necrosis factor alpha-(TNF alpha) or cytokine-induced neutrophil chemoattractant- (CINC) induced neutrophilia in guinea-pig lungs. Dexamethasone was a potent inhibitor of PAF- induced eosinophil accumulation, but higher doses of dexamethasone were required to inhibit IL-5-induced eosinophilia. LPS-induced neutrophilia was less sensitive to the inhibitory effects of dexamethasone, than PAF-induced eosinophilia. Both LPS- and TNF alpha-induced neutrophilia were inhibited by the same doses of dexamethasone. In contrast, higher doses of dexamethasone were required to inhibit CINC-induced neutrophilia. Since data in the literature show that PAF-induced eosinophilia in guinea-pig lungs is dependent on the generation of IL-5, it is concluded that inhibition of this response, by dexamethasone, is due to inhibition of release of IL-5. Similarly, although data in the literature show that LPS-induced neutrophilia is dependent on the generation of TNF alpha, it is concluded that inhibition of this response, by glucocorticoids, is due to an action on an event which occurs after the release of TNF alpha, possibly through inhibition of chemokine release.

Analysis of Variance↗
PubMed1996

Inhibition of IKs in guinea pig cardiac myocytes and guinea pig IsK channels by the chromanol 293B.

The chromanol derivative 293B was previously shown to inhibit a cAMP regulated K+ conductance in rat colon crypts. Subsequent studies on cloned K+ channels from the rat demonstrated that 293B blocks specifically IsK channels expressed in Xenopus oocytes, but does not affect the delayed and inward rectifier Kv1.1 and Kir2.1, respectively. In the present study, the specificity of 293B for the cardiac K+ conductances IKs and IKr, and for the cloned guinea pig IsK channel and the human HERG channel, which underly IKs and IKr, respectively, was analyzed. 293B inhibited both the slowly activating K+ conductance IKs in cardiac myocytes and guinea pig IsK channels expressed in Xenopus oocytes with a similar IC50 (2-6 micromol/l). In contrast, high concentrations of 293B had only a negligible effect on the more rapid activating IKr. Similarly, 293B exerted no effect on HERG channels expressed in Xenopus oocytes. In summary, 293B appears to be a rather specific inhibitor of IKs and the underlying IsK channels.

Animals↗
PubMed1980

Purification of guinea-pig plasma prekallikrein. Activation by prekallikrein activator derived from guinea-pig skin.

Prekallikrein was purified from guinea-pig plasma. The prekallikrein appeared homogeneous as a single-chain protein on polyacrylamide gels in the presence of sodium dodecyl sulfate (SDS) and beta-mercaptoethanol. The apparent molecular weight was 82 000 by SDS-polyacrylamide gel electrophoresis, 99 000 by gel filtration on a Sephadex G-150 column and 84 500 (protein part) by amino acid analysis. The isoelectric point was approx. 9.0. The purification method yielded 3.8 mg (A280 3.800) of prekallikrein from 500 ml of plasma. Kallikrein was generated from the prekallikrein by limited proteolytic action of a prekallikrein activator which was derived from guinea-pig skin. From analysis using SDS-polyacrylamide gel electrophoresis, the kallikrein has two fragments with apparent molecular weights of 52 000 and 40 000 which are linked by disulfide bond(s). The 40 000 molecular weight fragment was shown to incorporate [3H]diisopropylfluorophosphate. The kallikrein hydrolyzed the synthetic substrates containing the Phe-Arg sequence at the COOH-terminal, and it cleaved carbobenzyloxy-Phe-Arg-4-methylcoumaryl-7-amide more readily than Pro-Phe-Arg-methylcoumaryl-7-amide. The Km for the kallikrein with carbobenzyloxy-Phe-Arg-methylcoumaryl amide was 2 times 104 M. Also, the kallikrein showed negligible activities on peptide-methylcoumaryl amide-substrate for alpha-thrombin, Factor Xa or plasmin.

Amino Acids↗
PubMed1979

Inhibition by digoxin and SC4453 of (Na+ + K+)-ATPase prepared from human heart, guinea-pig heart and guinea-pig brain.

SC4453 is a digoxin analogue with a pyridazine instead of a lactone ring on C17 beta. SC4453 was compared with digoxin with respect to inhibition of (Na+ + K+)-ATPase prepared from human heart, guinea-pig heart and guinea-pig brain. SC4453 was slightly less potent than digoxin but showed a similar sensitivity to K+. As for cardenolides, species differences in sensitivity to SC4453 were accounted for by differences in the rate of dissociation from the receptors. These observations confirm that the human heart is one of the tissues most sensitive to cardiac glycosides.

Animals↗
PubMed1985

Electron microscopic observations concerning the in vivo uptake and release of the agent of guinea-pig inclusion conjunctivitis (Chlamydia psittaci) in guinea-pig exocervix.

This report details electron-microscopical observations concerning C. psittaci infection in vivo. The model employed was that of the guinea-pig infected at the exocervical region with the agent of guinea-pig inclusion conjunctivitis (GPIC). Our observations indicate that chlamydial particles gain access to their target cells by the mechanism of endocytosis. Single GPIC elementary bodies were seen to be positioned within individual endosomes. The observations reported here provide evidence that chlamydial particles that had undergone their developmental cycle within the exocervical epithelial cells may leave the epithelium in 2 ways; within entire infected cells that had been shed into the lumen of the cervix and by means of the liberation of chlamydial particles from disrupted cells. The mechanism of cell disruption and shedding is thought to involve the large number of PMNs observed to be present within the enlarged intercellular spaces of the infected epithelium.

Animals↗
PubMed1987

Selected physical and biochemical parameters in the streptozotocin-treated guinea pig: insights into the diabetic guinea pig model.

Since evidence suggests that ascorbic acid deficits may provoke certain diabetic complications, it becomes necessary to develop a diabetic animal model which, like man, is unable to synthesize this vitamin. To this end, the present study monitored the diabetogenic effects of streptozotocin (STZ, 150 mg/kg) in the male guinea pig, a species rarely used in diabetes research. Over a 3-week period, body weight and relative food intake were lower in the STZ group compared to controls. The mean daily water intake and urine volume of the STZ group after 1 week were 175 and 270% of their initial pretreatment values, respectively, while control values were unchanged. The STZ group also exhibited a persistent glycosuria throughout the study. At the end of 3 weeks, aldehyde fuchsin staining of pancreatic beta cell granules (an index of stored insulin) was 58% lower in the STZ group compared to controls. Plasma C-peptide (indicator of insulin secretion) was expressed in human equivalents (mean +/- SEM). C-peptide was reduced in the STZ group (103 +/- 65 pg/ml) compared to controls (549 +/- 96 pg/ml); however, no change in plasma glucose was observed. Plasma ascorbic acid levels also were lower for STZ animals (150 +/- 26 micrograms%) versus controls (410 +/- 28 micrograms%). This study 1) demonstrates a diabetic syndrome in the STZ-treated guinea pig based on a reduced growth rate, beta cell dysfunction, polydipsia, polyuria and glycosuria, and 2) suggests the usefulness of this diabetic model in studies of pathologic mechanisms influenced by ascorbic acid.

Animals↗