Guinea Pig Liver Research Articles

The Effectiveness of Ylang Ylang Oil (Cananga Odorata) as a Deparaffinizing Agent in Hematoxylin-Eosin Staining

Histological staining usually requires deparaffinization before starting the staining process. Deparaffinization is a paraffin removal step that often uses a xylol solution. Deparaffinization with xylol has disadvantages, including being toxic, harmful to the human body, and hazardous to the environment. A safer alternative to xylol is required. Ylang-ylang oil, which contains β-caryophyllene, is non-polar and can be used as a substitute for xylol. This study aimed to compare the staining quality of guinea pig liver tissue slides with and without heating as a deparaffinization agent in hematoxylin-eosin (HE) staining. The research set up a quasi-experimental approach using samples of guinea pig liver tissue slides. The sample size was calculated using the Federer formula (n-1) (t-1) ≥ 15, resulting in a total sample of 27 slides divided into three treatment groups: xylol, ylang-ylang oil with and without heating. The Kruskal-Wallis test was used to examine the data. The quality staining of guinea pig liver slides deparaffinized with xylol was 100% good, and deparaffinization of ylang-ylang oil with heating was 100% good, whereas deparaffinization with ylang-ylang oil without heating was 11.1% less good, and the quality was good with an 88.9%. The normality test indicated that the data were not normally distributed (p0.05). The Kruskal-Wallis test was then used.

Investigation on Adaptability and Applicability of Polymer-Mediated Cell Surface Engineering by Ligation with Transglutaminase.

Polymer-mediated cell surface engineering can be a powerful tool to modify the cell's biological behavior, but a simple ligation strategy must be identified. This manuscript assessed the use of transglutamination as a versatile and adaptable approach for cell surface engineering in various cellular models relevant to biomedical applications. This enzymatic approach was evaluated for its feasibility and potential for conjugating polymers to diverse cell surfaces and its biological effects. Transglutaminase-mediated ligation was successfully performed at temperatures ranging from 4 to 37 °C in as quickly as 30 min, while maintaining biocompatibility and preserving cell viability. This approach was successfully applied to nine different cell surfaces (including adherent cells and suspension cells) by optimizing the enzyme source (guinea pig liver vs microbial), buffer compositions, and incubation conditions. Finally, polymer-mediated cell surface engineering using transglutaminase exhibited immunocamouflage abilities for endothelial cells, T cells, and red blood cells by preventing the recognition of cell surface proteins by antibodies. Employing transglutaminase in polymer-mediated cell surface engineering is a promising approach to maximize its application in cell therapy and other biomedical applications.

Mitochondrial carbonic anhydrase VA and VB: properties and roles in health and disease.

Carbonic anhydrase V (CAV), a mitochondrial enzyme, was first isolated from guinea-pig liver and subsequently identified in mice and humans. Later, studies revealed that the mouse genome contains two mitochondrial CA sequences, named Car5A and Car5B. The CAVA enzyme is most highly expressed in the liver, whereas CAVB shows a broad tissue distribution. Car5A knockout mice demonstrated a predominant role for CAVA in ammonia detoxification, whereas the roles of CAVB in ureagenesis and gluconeogenesis were evident only in the absence of CAVA. Previous studies have suggested that CAVA is mainly involved in the provision of HCO3 - for biosynthetic processes. In children, mutations in the CA5A gene led to reduced CA activity, and the enzyme was sensitive to increased temperature. The metabolic profiles of these children showed a reduced supply of HCO3 - to the enzymes that take part in intermediary metabolism: carbamoylphosphate synthetase, pyruvate carboxylase, propionyl-CoA carboxylase and 3-methylcrotonyl-CoA carboxylase. Although the role of CAVB is still poorly understood, a recent study reported that it plays an essential role in human Sertoli cells, which sustain spermatogenesis. Metabolic disease associated with CAVA appears to be more common than other inborn errors of metabolism and responds well to treatment with N-carbamyl-l-glutamate. Therefore, early identification of hyperammonaemia will allow specific treatment with N-carbamyl-l-glutamate and prevent neurological sequelae. Carbonic anhydrase VA deficiency should therefore be considered a treatable condition in the differential diagnosis of hyperammonaemia in neonates and young children.

Liver in guinea pig: Scanning and transmission electron microscopic studies

The liver performs many functions, which support metabolism, immunity, digestion, detoxification, vitamin storage, and so on. The liver is the storage organ for fat-soluble vitamins, iron and copper. Six adult healthy guinea pigs of 16-32 weeks of age (Irrespective of sex) were procured from the Department of Laboratory Animal Medicine, TANUVAS as per ethical committee approval. Animals were dissected as per CPCSEA norms and liver pieces were utilized for scanning electron microscopy (SEM) and transmission electron microscopy (TEM) study. The study was performed to document the ultrastructural details of liver of guinea pigs by SEM and TEM. By SEM, the liver parenchyma appeared as lobular with anastomosed one cell thick hepatic cell plates, which appeared as continuous sheets with small to large holes representing sinusoids. The sinusoidal lumen was lined by two types of cells namely endothelial cells and Kupffer cells. Endothelial cells had numerous large and small cytoplasmic fenestrations. Presence of Kupffer cells along with Ito cells were observed in the sinusoids. By TEM, hepatocytes had angular shape with sinusoidal face and bile canalicular face. Hepatocytes had oval nucleus with peripheral heterochromatin and central electron lucent granules and a prominent nucleolus. Bile canaliculi were formed by two adjacent hepatocytes. Fenestrated endothelial cells with flat and elongated shape were found to be in the formation of hepatic sinusoidal wall. A narrow space of Disse was found between the sinusoidal endothelium and hepatocytes. Kupffer cells and pit cells were found within the sinusoidal lumen. Ito cells were found in the space of Disse. RESEARCH HIGHLIGHTS: By scanning electron microscopy, the liver parenchyma appeared as lobular with anastomosed one cell thick hepatic cell plates, which appeared as continuous sheets with small to large holes representing sinusoids. By transmission electron microscopy, hepatocytes had angular shape with sinusoidal face and bile canalicular face. Hepatocytes had oval nucleus with peripheral heterochromatin and central electron lucent granules and a prominent nucleolus.

Modelling Nonalcoholic Steatohepatitis In Vivo-A Close Transcriptomic Similarity Supports the Guinea Pig Disease Model.

The successful development of effective treatments against nonalcoholic steatohepatitis (NASH) is significantly set back by the limited availability of predictive preclinical models, thereby delaying and reducing patient recovery. Uniquely, the guinea pig NASH model develops hepatic histopathology and fibrosis resembling that of human patients, supported by similarities in selected cellular pathways. The high-throughput sequencing of guinea pig livers with fibrotic NASH (n = 6) and matched controls (n = 6) showed a clear separation of the transcriptomic profile between NASH and control animals. A comparison to NASH patients with mild disease (GSE126848) revealed a 45.2% overlap in differentially expressed genes, while pathway analysis showed a 34% match between the top 50 enriched pathways in patients with advanced NASH (GSE49541) and guinea pigs. Gene set enrichment analysis highlighted the similarity to human patients (GSE49541), also when compared to three murine models (GSE52748, GSE38141, GSE67680), and leading edge genes THRSP, CCL20 and CD44 were highly expressed in both guinea pigs and NASH patients. Nine candidate genes were identified as highly correlated with hepatic fibrosis (correlation coefficient > 0.8), and showed a similar expression pattern in NASH patients. Of these, two candidate genes (VWF and SERPINB9) encode secreted factors, warranting further investigations as potential biomarkers of human NASH progression. This study demonstrates key similarities in guinea pig and human NASH, supporting increased predictability when translating research findings to human patients.

Novel amide and imidazole compounds as potent hematopoietic prostaglandin D2 synthase inhibitors

In seeking novel and potent small molecule hematopoietic prostaglandin D2 synthase (H-PGDS) inhibitors as potential therapies for PGD2-mediated diseases and conditions, we explored a series comprising multiple aryl/heteroaryl rings attached in a linear arrangement. Each compound incorporates an amide or imidazole “linker” between the pyrimidine or pyridine “core” ring and the “tail” ring system. We synthesized and screened twenty analogs by fluorescence polarization binding assay, thermal shift assay, glutathione S-transferase inhibition assay, and a cell-based assay measuring suppression of LPS-induced PGD2 stimulation. Amide analogs show ten-fold greater shift in the thermal shift assay in the presence of glutathione (GSH) versus the same assay run in the absence of GSH. The imidazole analogs did not produce a significant change in thermal shift between the two assay conditions, suggesting a possible stabilization effect of the amide linker in the synthase-GSH-inhibitor complex. Imidazole analog 23, (KMN-010034) demonstrates superior potency across the in vitro assays and good in vitro metabolic stability in both human and guinea pig liver microsomes.

Safety research on treatment of cough reflex disorder after cerebral hemorrhage with crossing nape electroacupuncture in guinea pig

To observe the effect of crossing nape electroacupuncture(EA) on cough count (CCnt), cough incubation period and blood routine, liver function, renal function, myocardial enzymology, and heart, liver and kidney pathological structure in guinea pig with cough reflex disorder after cerebral hemorrhage, so as to evaluate the efficacy and safety of crossing nape EA in the treatment of cough reflex disorder after cerebral hemorrhage. A total of 160 male pure white guinea pigs were randomly divided into normal group, model group, acupuncture group, crossing nape EA group and nape EA group (n=32 in each group). These 5 groups were further divided into 1, 3, 7 and 14 d subgroups(n=8 in each subgroup). The model of cough reflex disorder after cerebral hemorrhage was established by injection of the guinea pigs' autoblood (50 μL) into the basal ganglia region confirmed by Longa's neurologic examination grading system(0-4 points). Acupuncture was applied to bilateral "Fengchi" (GB20) and "Yifeng" (SJ17) in the acupuncture group. In the crossing nape EA group, the positive pole of the needle is connected to SJ17, while the negative pole is connected to the opposite side of GB20(2 Hz, 0.5 mA). In the nape EA group, the positive pole of the needle is connected to SJ17, while the negative pole is connected to the same side of GB20(2 Hz, 0.5 mA). All treatments were applied 20 min each time, once a day. The changes of CCnt and cough incubation period were recorded by Buxco device. The changes of blood routine, liver function, kidney function, myocardial enzyme and other laboratory indexes were monitored by automatic analyzer instrument. The pathological changes of heart, liver and kidney of guinea pigs were observed by transmission electron microscopy. Compared with the normal group, the guinea pigs' neurological deficit scores in the model group were significantly increased at each time point (P<0.01). Compared with the model group, the neurological deficit scores of the acupuncture group, crossing nape EA group and nape EA group at 3 d, 7 d and 14 d all decreased (P<0.01, P<0.05). Following modeling, the CCnt at each time point in the model group was significantly reduced (P<0.01), and the cough latency was significantly prolonged (P<0.01). After interventions, the CCnts were increased and the incubation periods of cough were shortened (P<0.05, P<0.01) at 7 d and 14 d in the 3 intervention groups, and were superior in the crossing nape EA group than those of acupuncture group and nape EA group (P<0.05, P<0.01). The improvement degrees of these 2 indexes in the nape EA group at 14 d were better than those of the acupuncture group (P<0.05). There were no significant differences among the 3 groups in red blood cells counting, hemoglobin, myocardial enzymes, liver and kidney function (P>0.05). Compared with the normal group, the WBC counts in all the time points (except 1 d after operation) were significantly increased(P<0.01) in the model group. In comparison with the model group, the WBC counts at 3 d in crossing nape EA group, and at 7 d and 14 d in the 3 intervention groups decreased (P<0.01, P<0.05). Meanwhile, the WBC counts were lower in the crossing nape EA group at 7 d and 14 d than those of acupuncture group and nape EA group (P<0.05). The results of transmission electron microscopy showed that the histopathological structure of heart, liver and kidney of guinea pigs in each group had no significant changes. Crossing nape EA is safe and effective in the treatment of cough reflex disorder after cerebral hemorrhage in guinea pigs. In addition, guinea pigs will have an inflammatory response after cerebral hemorrhage, and crossing nape EA may have a certain anti-inflammatory effect.

Early Life Deficiencies in Ascorbate and Cysteine Impact the Long-term Glutathione Metabolism in Liver and Lungs of Guinea Pigs

Early Life Deficiencies in Ascorbate and Cysteine Impact the Long-term Glutathione Metabolism in Liver and Lungs of Guinea Pigs

Differences in xanthotoxin metabolites in seven mammalian liver microsomes.

Xanthotoxin, abundantly occurring in fruits, vegetables, grapefruit juice and oils, is widely used in medicine for the treatment of psoriasis and vitiligo. Xanthotoxin possesses the ability to inhibit mechanism-based cytochrome P450 (CYP450)-mediated activities in rats and mice. Furthermore, it time-dependently obstructs a number of CYP450-mediated functions in humans. CYP450 enzymes are most abundant in the liver and induce metabolic activation of numerous xenobiotic compounds. The present study aimed to identify the similarities and differences in xanthotoxin metabolism in liver microsomes of 7 mammalian species, including human liver microsomes (HLM), Rhesus monkey liver microsomes (RMLM), Cynomolgus monkey liver microsomes (CMLM), Sprague Dawley rat liver microsomes (RLM), mouse liver microsomes (MLM), Dunkin Hartley guinea pig liver microsomes (PLM) and Beagle dog liver microsomes (DLM). Ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometric analysis was used to determine the metabolites. A total of 3 metabolites were detected in RMLM, CMLM and RLM. Furthermore, two metabolites were observed in MLM, HLM, PLM and DLM. By analyzing the type and quantity of metabolites, the metabolism of xanthotoxin in MLM was indicated to be most similar to that in HLM. The metabolic transformations of xanthotoxin in the liver microsomes of the 7 species were analyzed in further detail. On the whole, the results of the present study provide a deeper understanding of the metabolic patterns of xanthotoxin in liver microsomes of different species, which may prove to be advantageous regarding the metabolic mechanisms of action of xanthotoxin. Further insight into drug metabolism with respect to different species will also aid in the selection of appropriate animal models for further research.

Relationship between redox potential of glutathione and DNA methylation level in liver of newborn guinea pigs

ABSTRACT The metabolism of DNA methylation is reported to be sensitive to oxidant molecules or oxidative stress. Hypothesis: early-life oxidative stress characterized by the redox potential of glutathione influences the DNA methylation level. The in vivo study aimed at the impact of modulating redox potential of glutathione on DNA methylation. Newborn guinea pigs received different nutritive modalities for 4 days: oral nutrition, parenteral nutrition including lipid emulsion Intralipid (PN-IL) or SMOFLipid (PN-SF), protected or not from ambient light. Livers were collected for biochemical determinations. Redox potential (p < 0.001) and DNA methylation (p < 0.01) were higher in PN-infused animals and even higher in PN-SF. Their positive correlation was significant (r2 = 0.51; p < 0.001). Methylation activity was higher in PN groups (p < 0.01). Protein levels of DNA methyltransferase (DNMT)-1 were lower in PN groups (p < 0.01) while those of both DNMT3a isoforms were increased (p < 0.01) and significantly correlated with redox potential (r2 > 0.42; p < 0.001). The ratio of SAM (substrate) to SAH (inhibitor) was positively correlated with the redox potential (r2 = 0.36; p < 0.001). In conclusion, early in life, the redox potential value strongly influences the DNA methylation metabolism, resulting in an increase of DNA methylation as a function of increased oxidative stress. These results support the notion that early-life oxidative stress can reprogram the metabolism epigenetically. This study emphasizes once again the importance of improving the quality of parenteral nutrition solutions administered early in life, especially to newborn infants. Abbreviation of Title: Parenteral nutrition and DNA methylation

Species-Specific Glucose-6-Phosphatase Activity in the Small Intestine-Studies in Three Different Mammalian Models.

Besides the liver, which has always been considered the major source of endogenous glucose production in all post-absorptive situations, kidneys and intestines can also produce glucose in blood, particularly during fasting and under protein feeding. However, observations gained in different experimental animals have given ambiguous results concerning the presence of the glucose-6-phosphatase system in the small intestine. The aim of this study was to better define the species-related differences of this putative gluconeogenic organ in glucose homeostasis. The components of the glucose-6-phosphatase system (i.e., glucose-6-phosphate transporter and glucose-6-phosphatase itself) were analyzed in homogenates or microsomal fractions prepared from the small intestine mucosae and liver of rats, guinea pigs, and humans. Protein and mRNA levels, as well as glucose-6-phosphatase activities, were detected. The results showed that the glucose-6-phosphatase system is poorly represented in the small intestine of rats; on the other hand, significant expressions of glucose-6-phosphate transporter and of the glucose-6-phosphatase were found in the small intestine of guinea pigs and homo sapiens. The activity of the recently described fructose-6-phosphate transporter–intraluminal hexose isomerase pathway was also present in intestinal microsomes from these two species. The results demonstrate that the gluconeogenic role of the small intestine is highly species-specific and presumably dependent on feeding behavior (e.g., fructose consumption) and the actual state of metabolism.

Toxicity Effect by Binahong (Anredera cordifolia) Leaf Extract in Histopathology and Liver Weight of Guinea Pigs (Cavia cobaya)

The aim of this research was to determine the toxic effect of Anredera cordifolia leaf extract on the Cavia cobaya liver which was evaluated by the histopathological examination of liver tissue. The materials used were 8 female guinea pigs 2.5 months old that were divided into 4 groups by simple random sampling, each treatment was given to 2 female C. cobaya. Treatments given were 0, 10, 50 and 90 mg of A. cordifolia leaf extract/head, designated as T0, T1, T2 and T3, respectively. Materials were given treatment daily as long as 10 days prepartum. All of the guinea pigs were slaughtered at day 11, and the liver were taken to examined their histopathological changes. Each of the liver tissues were processed by paraffin block-embedded and hematoxylin eosin (HE) staining method. The results of this study indicate the presence of albuminosa degeneration or mild degeneration (DH +) from group control and hydropic degeneration or moderate degeneration (DH ++) in all treatment groups and the weight of C. cobaya liver which was given an extract of A. cordifolia 50 mg/head was not significantly different from the control but was significantly different from 10 and 90 mg/head. The conclusion was Binahong's (A. cordifolia) leaves extract up to the dosage 90 mg/head had no significantly toxicity effect on the liver of guinea pigs (C. cobaya).

Characterization of a cold-active transglutaminase from a crayfish, Pacifastacus leniusculus

Transglutaminase (TGase) from signal crayfish (Pacifastacus leniusculus) and its activity at low temperatures was studied. TGase is an abundant protein in the hematopoietic (HPT) cells and this tissue was used for TGase enzyme preparation. The optimal temperature and pH for the activity of crayfish TGase were determined. We found that TGase activity at 4 °C showed nearly the same activity as at a temperature of 22 °C. TGase activity from crayfish was compared with guinea pig liver TGase activity at 4 °C and the crayfish TGase displayed a higher activity while guinea pig liver TGase had a very low activity at this low temperature. By comparing kinetic parameters to guinea pig liver TGase, the results showed that a high activity of crayfish TGase was due to a decreasing Km value for pentylamine as a substrate, while it did not affect the kcat value (at 22 °C). The amino acid sequences of a krill and a crayfish TGase, which both are cold adapted, do not give any clue to why these two enzymes are cold-adapted. These results demonstrate that crayfish TGase is adapted to have significant activity at low temperatures and since crayfish are living in quite cold waters this is an interesting adaptation of this enzyme.

Comparative Study of the Liver Anatomy in the Rat, Rabbit, Guinea Pig and Chinchilla

In liver surgical and histological research, small rodents are the most used experimental models. Although the small animals liver is typically lobulated and its macroscopic appearance do not resemble that of the compact human liver, a high degree of lobulation equivalence, allow the use of small rodents in biomedical research. The macroscopic anatomy of the liver of the rat, rabbit, guinea pig and chinchilla was studied from a comparative standpoint. The topography, lobulation and the connection elements of the liver were examined by detailed in situ observation and explanted liver of forty specimens.The rat liver (Hepar) consists of four distinct lobes of different size: the left lateral lobe - LLL (Lobus hepatis sinister lateralis), the median lobe - ML, the right lobe – RL (Lobus hepatis dexter) and the caudate lobe CL (Lobus caudatus). The largest lobe was the median lobe. The rabbit liver consists of five lobes: left lateral lobe - LLL, left medial lobe - LML (Lobus hepatis sinister medialis), right lobe - RL, quadrate lobe – QL (Lobus quadratus) and caudate lobe - CL. The most developed lobe was the left lateral lobe. The caudate lobe had a very narrow attachment on the hilar region. The guinea pig liver show six lobes: left lateral lobe - LLL, left medial lobe - LML, right lateral lobe – RLL (Lobus hepatis dexter lateralis), right medial lobe – RML (Lobus hepatis dexter medialis), quadrate lobe - QL and caudate lobe - CL. The largest lobe of this specie was the left lateral lobe. In chinchilla liver showed four lobes like in the rat. In the rats the most developed hepatic ligament was the falciform ligament (Lig. Falciforme hepatis) which spans from xyphoid process of the sternum and diaphragm to the liver, beginning at the interlobular fissure. The coronary ligament (Lig. Coronarium hepatis) was well developed in all rats. Interlobular ligaments connect the left lateral lobe with the upper caudate lobe. In rabbits, guinea pigs and chinchillas the connection elements were represented by the falciform ligament, coronary ligament, right (Lig.triangulare dextrum) and left triangular ligaments (Lig. Triangulare sinistrum), hepatorenal ligament (Lig.hepatorenale) and hepatoduodenal ligament (Lig. hepatoduodenale) with varying degrees of development.Based on detailed study of the macroscopic anatomy of rat, rabbit, guinea pig and chinchilla a proper experimental model in liver research, could be assessed. In this regard, the vascular anatomy of the liver in the mentioned species is of a great importance and it is subject of another report.

Long-term Impact of added Glutathione into Parenteral Nutrition Administered During the First week of life on Redox Potential and Energy Metabolism Enzymes in Guinea pig liver

Introduction Peroxides are generated in parenteral nutrition (PN). Infusion of PN or H2O2 in the first week of life of animals alters later in life their hepatic energy metabolism. Glutathione addition in PN prevented pulmonary oxidative stress induced by PN in newborn guinea pigs (GP). Hypothesis: Addition of glutathione into PN prevents the long-term impact of PN on activities of key enzymes of energy metabolism (glucokinase (GK), phosphofructokinase (PFK) and acetyl-CoA carboxylase (ACC)). Methods 4 groups (N=48) of 3-day old GP were used. Control: no manipulation, fed ad libitum all time; PN: animals nourished exclusively with a complete PN via a catheter; PN+ 6 or 12 µM GSSG; GSSG was used as pro-GSH. After 4 days, hepatic redox potential was measured in half of GP. The other half started oral diet. At 16 weeks of age, liver was collected for determination of GSH, GSSG and redox potential (capillary electrophoresis, Nernst’s equation), activities (U: nmol/min/mg prot) of PFK, GK (calorimetric method), and ACC (method with radioactive tracer). Data (mean±sem) were analyzed by ANOVA, p Results Immediately after treatments, there was no difference between groups for redox potential (mV) (-231±1). Four months later, redox potential, GSH and GSSG (nmol/mg prot) were lower in PN groups independently of GSSG addition, relatively to control (respectively, PN groups: -235±1, 69±2, 0.8±0.1 vs. Control: -229±2, 81±5, 1.8±0.3). ACC activity was higher in PN group (4.5±0.3 U) and greater in NP+GSSG groups (5.7±0.3 U) relatively to control (3.2±0.2 U). GK and PFK activities did not differ. Conclusion PN early in life induces later in liver reduction of redox potential and higher activity of a key enzyme of lipogenesis (ACC). In contrast to beneficial effect previously observed in lungs, addition of GSSG into PN did not prevent the long-term effects of PN on the liver.

Decarboxylation Pathways of Amino Acids in Some Mammal and Bird Tissues

The following data were obtained on the decarboxylation pathways of amino acids in some mammal and bird tissue homogenates: 1. PIG KIDNEY AND LIVER: Three preformed amine-like compounds were observed in the kidney and strong disappearance of added serotonin during anaerobic and aerobic incubation (strong conjugases? and monoamine oxidase activities). No significant disappearance of added histamine was found after anaerobic or aerobic incubation. In the liver serotonin disappeared only after aerobic incubation. Free glucose (reacting with the added amines) was present in the liver but not in the kidney. 2. Ox ADRENALS: Two preformed amine-like compounds were present which are not noradrenalin or dopa amine. Absence of conjugases or amine oxidases. 3. GUINEA PIG LIVER; Strong disappearance of added serotonin after anaerobic incubation. No significant disappearance of added histamine in both types of incubations, 4. Tarauco corythaix LIVER: Strong anaerobic and aerobic disappearance of added serotonin and very slight if any disappearance of histamine in both types of incubation. 5. Cathartes ama septentrionalis (TURKEY BUZZARD) LIVER: Absence of anaerobic metabolism of added serotonin or histamine (absence of conju­gases?) and strong aerobic disappearance of both amines after incubation with both amines, (strong mono and diamine oxidase activities). The Eollowing data were obtained on the decarboxylation pathways oE amino acids in some mammaI and bird tissue homogenates: 1 . P IG KIDNEY AND LIVER: Three preformed amine-like compounds were observed in the kidney and' strong disappearance oE added serotonin during anaerobic and aerobic incubation (strong conjugases? and monoamine oxidase activities). No signiEicant disappearance of added histamine was found after anaerobic or aerobic incubation. In the liver serotonin disappeared only after. aerobic incubation. Free glucose (reacting with the added amines) was present in the liver but not in the kidney. 2. Ox ADRENALS: Two preEormed amine-like compounds were present which are not noradrenalin or dopa amine. Absence oE conjugases or amine oxidases. 3. GUINEA PIe; UVER; Strong disappearance of added serotonin afterREVIs'rA DE InOLOGIA TROPICAt anaerobic incubation. No significant dis:lppearance of addcd histaminc in both typcs of incubations, 4. T arauco cOI'J'thclIx L1VER: Strong anaerobic and aerobic disappearance of added serotonin and very slight if any disappearance of histamine in both types of incubation. 5. CatiJartes ama Jeptentrionalu (TURKEY BUZZARD) UVER: Absence of anaerobic metabolism of added serotonin or histamine (absence of conju­ gases?) and strong aerobic disappearance of both amines after incubation with both amines, (strong mono and diamine oxidase activities).

Effects of betaine supplementation on nitric oxide metabolism, atherosclerotic parameters, and fatty liver in guinea pigs fed a high cholesterol plus methionine diet.

The aim of this study was to investigate the effect of high cholesterol (CHOL) and CHOL+methionine (MET) diets on atherogenic and oxidative index parameters and on the factors that influence nitric oxide (NO) bioavailability. Also, attempts were made to determine whether dietary betaine (BET) resulted in any improvement in the changes that occurred after CHOL+MET administration. Guinea pigs were fed chow containing 1.5% CHOL with or without 2% MET for 10wk. A third group received the CHOL+MET+BET diet. Control groups were given standard chow or standard chow+BET. Arginine, NO, nitrotyrosine (NT), and asymmetric dimethylarginine (ADMA) levels; lipid profile; and dimethylarginine dimethylaminohydrolase (DDAH) activity were measured. The liver and aorta were subjected to histopathologic analysis. The CHOL+MET diet caused higher serum CHOL and homocysteine levels, but no further increases were seen in aortic CHOL and diene conjugate (DC) levels and histopathologic lesions as compared with the CHOL group. Hepatic lipids and DC levels were also higher, and histopathologic lesions were more severe. CHOL+MET feeding increased ADMA and NT levels as compared with those of the CHOL-fed group. When BET (1g/kg body weight/d) was added to the CHOL+MET diet, homocysteine and lipid levels decreased and histopathologic changes were reversed. BET diet decreased serum ADMA and hepatic and aortic DC levels and partly restored DDAH activity. BET supplementation may be effective in preventing hyperlipidemia, disturbed NO availability, oxidative stress, and the development of fatty liver and atherosclerotic lesions that might result from excess amounts of cholesterol and methionine in the diet.

Role of astakine1 in regulating transglutaminase activity

Transglutaminase (TGase) has been implicated in maintaining the undifferentiated stage of hematopoietic stem cells (HSC) in the crayfish Pacifastacus leniusculus. TGase activity has been reported to be regulated by astakine1, an essential crayfish cytokine for inducing new hemocyte synthesis in hematopoietic tissue (HPT). Here, the role of astakine1 in TGase activity regulation and clotting protein (CP) cross-linking was characterized. A reduction in TGase activity was observed by the addition of purified astakine1 in vitro for both endogenous crayfish TGase and a commercial purified guinea pig liver TGase. As a result, we observed that astakine1 inhibits TGase enzyme activity and acts as a non-competitive inhibitor for the TGase enzyme. Additionally, the clotting reaction was impaired in the presence of astakine1. A decrease in TGase-mediated crosslinking of ε(γ-glutamyl)-lysine bonds was also observed in the presence of astakine1. In conclusion, this study shows that astakine1 acts as an inhibitor of TGase activity and that it also affects CP cross-linking during crayfish hematopoiesis.

Tissue Transglutaminase Modulates Vascular Stiffness and Function Through Crosslinking-Dependent and Crosslinking-Independent Functions.

BackgroundThe structural elements of the vascular wall, namely, extracellular matrix and smooth muscle cells (SMCs), contribute to the overall stiffness of the vessel. In this study, we examined the crosslinking‐dependent and crosslinking‐independent roles of tissue transglutaminase (TG2) in vascular function and stiffness.Methods and Results SMCs were isolated from the aortae of TG2−/− and wild‐type (WT) mice. Cell adhesion was examined by using electrical cell–substrate impedance sensing and PicoGreen assay. Cell motility was examined using a Boyden chamber assay. Cell proliferation was examined by electrical cell–substrate impedance sensing and EdU incorporation assays. Cell micromechanics were studied using magnetic torsion cytometry and spontaneous nanobead tracer motions. Aortic mechanics were examined by tensile testing. Vasoreactivity was studied by wire myography. SMCs from TG2−/− mice had delayed adhesion, reduced motility, and accelerated de‐adhesion and proliferation rates compared with those from WT. TG2−/− SMCs were stiffer and displayed fewer cytoskeletal remodeling events than WT. Collagen assembly was delayed in TG2−/− SMCs and recovered with adenoviral transduction of TG2. Aortic rings from TG2−/− mice were less stiff than those from WT; stiffness was partly recovered by incubation with guinea pig liver TG2 independent of crosslinking function. TG2−/− rings showed augmented response to phenylephrine‐mediated vasoconstriction when compared with WT. In human coronary arteries, vascular media and plaque, high abundance of fibronectin expression, and colocalization with TG2 were observed.Conclusions TG2 modulates vascular function/tone by altering SMC contractility independent of its crosslinking function and contributes to vascular stiffness by regulating SMC proliferation and matrix remodeling.

Expression Profile of the Integrin Receptor Subunits in the Guinea Pig Sclera

ABSTRACTPurpose: The ocular dimensional changes in myopia reflect increased scleral remodeling, and in high myopia, loss of scleral integrity leads to biomechanical weakening and continued scleral creep. As integrins, a type of cell surface receptors, have been linked to scleral remodeling, they represent potential targets for myopia therapies. As a first step, this study aimed to characterize the integrin subunits at the messenger RNA level in the sclera of the guinea pig, a more recently added but increasingly used animal model for myopia research.Methods: Primers for α and β integrin subunits were designed using NCBI/UCSC Genome Browser and Primer3 software tools. Total RNA was extracted from normal scleral tissue and isolated cultured scleral fibroblasts, as well as liver and lung, as reference tissues, all from guinea pig. cDNA was produced by reverse transcription, PCR was used to amplify products of predetermined sizes, and products were sequenced using standard methods.Results: Guinea pig scleral tissue expressed all known integrin alpha subunits except αD and αE. The latter integrin subunits were also not expressed by cultured guinea pig scleral fibroblasts; however, their expression was confirmed in guinea pig liver. In addition, isolated cultured fibroblasts did not express integrin subunits αL, αM, and αX. This difference between results for cultured cells and intact sclera presumably reflects the presence in the latter of additional cell types. Both guinea pig scleral tissue and isolated scleral fibroblasts expressed all known integrin beta subunits. All results were verified through sequencing.Conclusion: The possible contributions of integrins to scleral remodeling make them plausible targets for myopia prevention. Data from this study will help guide future ex vivo and in vitro studies directed at understanding the relationship between scleral integrins and ocular growth regulation in the guinea pig model for myopia.