Alterations in biliary lipids of mice during dehydrocholic acid feeding

Mice were fed a lithogenic diet consisting of Purina chow and 0.5% dehydrocholic acid (DHA group). Controls received Purina chow. Every 2 wk for 20 wk animals were killed, and biliary phospholipid, cholesterol, and bile salt concentrations were determined, as well as the extent of gallstone formation. With time there was a gradual, significant decline in the concentration and the relative composition of phospholipid in both groups compared with initial values. There was a significant increase in biliary cholesterol concentration and relative amount in the DHA group compared with the control. No significant differences were found in the relative amounts of bile salt or phospholipid between the two groups. Feeding DHA resulted in an increased concentration of bile salts and the sum of measured lipid compared with controls. After 8 wk, gallstones were found in approximately 60% of autopsied animals and correlated with increased cholesterol concentration. Our data support the hypothesis that there is a component of cholesterol secretion that may not be bile salt- or phospholipid-dependent. Our data also suggest that biliary phospholipid secretion decreases with age.     

Anatomic changes in the biliary tract and pancreas in patients with diabetes mellitus diagnosed by endoscopic retrograde cholangiopancreatography]

Structural changes in both biliary tract and pancreas have been assessed with endoscopic retrograde cholangiopancreatography in 100 diabetic patients divided into subgroups depending on the type of diabetes mellitus, i.e. type I, type II and III-pancreatic. Control group included 100 randomly selected patients without diabetes mellitus in whom endoscopic retrograde cholangiopancreatography has been performed for various indications. Structural changes in the biliary tract and pancreas have been more frequent in diabetic patients than in the control group (47 and 75% vs 32 and 30%, respectively). Cholelithiasis has been noted in 27.8% of patients with type II diabetes mellitus and in 11.3% of patients with type I diabetes mellitus; obesity has been found in 57 and 12% of patients, respectively. Other biliary tract disorders, mainly in the form of segmental stenosis or dilatation of the common bile duct, have been more frequent in patients with type II diabetes mellitus. Pancreatic disorders, assessed with the aid of Cambridge classification, have been noted in all patients with pancreatic diabetes and in 80.7% of patients with diabetes mellitus type I. Incidence of so-called doubtful and mild disorders has been more frequent (22.2 and 24.1%, respectively) in patients with diabetes mellitus type II whereas "moderate" and "severe" disorders have been significantly less frequent (7.4 and 1.9% of patients). The results indicate, that endoscopic retrograde cholangiopancreatography is useful in the assessment of bile ducts structure and pancreatic exocrine activity in diabetic patients in whom disorders are more frequent.     

Cellular changes during the infusion of high dose intravenous immunoglobulin

With the ever widening group of autoimmune conditions that are beneficially affected by infusions of high dose immunoglobulin the possible mechanisms of action of such therapy appear increasingly complex. Fc mediated blockade of the mononuclear phagocyte system is an acknowledged early effect. This is, however, accompanied by a decrease of neutrophil counts which suggests that IgG binding to the neutrophil may be a mechanism of action. The decrease of neutrophil counts is transient but in immune thrombocytopenia is inversely proportional to the platelet response observed. In parallel to the effect on the neutrophil there are changes in the lymphocyte subsets with reversal of the T helper/suppressor ratio and alterations in the individual cellular constituents of each subset that correlate with the clinical response. The observed changes in B cell numbers and function suggest that T dependent and independent antibody production is effected by intravenous immunoglobulin. It is increasingly clear that in ITP at least the clinical response to IV IgG is a summation of several cellular events and their balance reflects the ultimate outcome. It may eventually be possible to use these observations to predict the likely outcome in the individual patient of this mode of therapy.     

A technique for retrograde intubation in mice

Endrotracheal intubation is critical for some experimental studies in mice, but the animals' small size makes the procedure difficult. The authors describe a new, easily learned retrograde intubation method using angioplasty guide wire. They twice intubated anesthetized mice successfully with no airway complications caused by puncture of the trachea.     

Maternal cardiovascular changes during pregnancy and postpartum in mice

Genetically altered mice may provide useful models for exploring cardiovascular regulation during pregnancy and postpartum if changes in mice mimic humans. We found in awake ICR (CD-1) mice at 17.5 days gestation that hematocrit was reduced 18%, and the pressor response to intravenous angiotensin II was reduced ~33%. Arterial pressure in awake mice was 12% lower in early pregnancy (3.5 days) than late pregnancy (17.5 days) and postpartum (3 and 17 days after delivery), whereas heart rate was 10-20% higher in the peripartum period (17.5 days gestation and 3 days postpartum). In late pregnancy, cardiac output under isoflurane anesthesia was 64% higher than in nonpregnant mice, due to a 37% increase in stroke volume and a 17% increase in heart rate. All changes P < 0.05. We conclude that, as in humans, mice exhibit hypotension in early pregnancy, and a blunted pressor response to angiotensin II, a decrease in hematocrit, and a marked increase in cardiac output in late pregnancy.     

Interaction between plastid and mitochondrial retrograde signalling pathways during changes to plastid redox status

Mitochondria and chloroplasts depend upon each other; photosynthesis provides substrates for mitochondrial respiration and mitochondrial metabolism is essential for sustaining photosynthetic carbon assimilation. In addition, mitochondrial respiration protects photosynthesis against photoinhibition by dissipating excess redox equivalents from the chloroplasts. Genetic defects in mitochondrial function result in an excessive reduction and energization of the chloroplast. Thus, it is clear that the activities of mitochondria and plastids need to be coordinated, but the manner by which the organelles communicate to coordinate their activities is unknown. The regulator of alternative oxidase (rao1) mutant was isolated as a mutant unable to induce AOX1a expression in response to the inhibitor of the mitochondrial cytochrome c reductase (complex III), antimycin A. RAO1 encodes the nuclear localized cyclin-dependent kinase E1 (CDKE1). Interestingly, the rao1 mutant demonstrates a genome uncoupled phenotype also in response to redox changes in the photosynthetic electron transport chain. Thus, CDKE1 was shown to regulate both LIGHT HARVESTING COMPLEX B (LHCB) and ALTERNATIVE OXIDASE 1 (AOX1a) expression in response to retrograde signals. Our results suggest that CDKE1 is a central nuclear component integrating mitochondrial and plastid retrograde signals and plays a role in regulating energy metabolism during the response to stress.     

Reclassification of "atypical" diagnoses in endoscopic retrograde cholangiopancreaticography-guided biliary brushings

OBJECTIVE: To evaluate the usefulness of reclassifying "atypical" diagnoses in reporting biliary cytology using strict morphologic criteria. STUDY DESIGN: Cytologic specimens from 139 patients (direct, alcohol-fixed smears or cytocentrifuge preparations) were evaluated. Diagnoses were benign (70), atypical (36) and malignant (33). Using strict criteria--major (nuclear contour, chromatin pattern) and minor (polarity, cell types, nuclear size, nuclear grooves, nucleoli, mitosis, nuclear/cytoplasmic [N/C] ratio)--atypical cases were reevaluated and reclassified. Follow-up (F/U) was available on all cases. RESULTS: Atypical cases, (36) were reclassified as malignant (26), atypical favor benign (2)/reactive (3) and atypical, not otherwise specified (NOS) (5). Cases reclassified as malignant showed irregular nuclear contours, chromatin irregularities and rare mitosis. Nuclear enlargement, nucleoli and cellularity varied widely in all groups. N/C ratio was increased in most reclassified malignant cases. All 26 malignant reclassifications correlated with F/U of malignancy. Benign and reactive cases (5) were negative for malignancy on F/U (4), and in 1 case a metastatic carcinoma involving the biliary tree was found. In the 5 atypical (NOS) cases, F/U showed malignancy (3) and pancreatitis (2). Cytocentrifuge preparations made in our laboratory were of superior quality when compared to other methods of cell preparation. CONCLUSION: Irregularities in nuclear membrane and abnormal chromatin pattern were the most consistently useful features correlating with malignancy. The sensitivity and specificity of biliary brush cytology can be enhanced by using strict cytomorphologic criteria and proper collection and fixation, all of which decrease atypical diagnoses.     

Morphological changes caused by experimental Streptococcus uberis mastitis in mice following intramammary infusion of pokeweed mitogen

Mice were used as models for bovine mastitis in an attempt to modify the susceptibility of mammary glands to Streptococcus uberis infection. Murine mammary glands were injected with pokeweed mitogen (PWM) prior to experimental bacterial challenge to accelerate involution and enhance antimicrobial mechanisms. PWM injection reduced the numbers of streptococci recovered when compared to controls. Histological examination of tissues from PWM-treated mice revealed a reduction in secretory activity and advanced involution. PWM-treated tissues had considerably more leukocytes infiltrating the epithelium, lumen, and underlying connective tissue. Bacteria were observed within the epithelium and alveolar lumen and internalized within neutrophils and macrophages in both PWM-injected and control tissue. Results of this study suggest PWM injection provided some protection against S. uberis mastitis by accelerating mammary involution, enhancing antimicrobial defenses, and facilitating a marked cellular response prior to bacterial challenge.     

Manometric transduction in enzyme biosensors

The combination of enzymatic recognition and manometric transduction is explored, using enzymes that consume or evolve a gas with low solubility in aqueous media. A design is discussed whereby change in partial pressure of a gas in the headspace is related to the turnover of analyte by the enzyme. Headspace and sample volume dimensions are considered, demonstrating the influence of flux at the air-water interface. The relative importance of diffusion and reaction for the enzyme solution is shown. When enzyme kinetics dominate, the concentration gradient is low and the overall kinetics are determined by the total amount of active enzyme, reducing either enzyme concentration or enzyme layer thickness will reduce the diffusion limitation. A Teflon-enzyme composite is presented to allow a reuseable immobilised enzyme preparation and a disc with stirring magnet identified as an efficient configuration. A glucose oxidase system was tested in the monitoring of glucose consumption during fermentation. Application to other enzyme systems is discussed.     

Compensatory changes in enzymes of arginine metabolism during renal hypertrophy in mice

The present study investigates enzyme activities of the urea cycle, transamidinase and ornithine–proline inter-conversion in the hypertrophied kidney after unilateral nephrectomy in mice. Surgical removal of the left kidney in mice led to compensatory enlargement of the right kidney after 1 and 14 days. This renal growth was associated with an increase in glomerular volume (but not number) and enlargement of the proximal convoluted tubules. The total renal protein content increased in proportion to the increase in kidney weight, but the protein per gram weight of kidney did not change. The specific activity of only ornithine aminotransferase (OAT), the rate-limiting enzyme in the conversion of ornithine to proline, increased in 2 weeks of hypertrophy. The specific activity of all other enzymes was unchanged. However, the total enzyme activity per kidney of all the enzymes, without exception, was elevated in the hypertrophied kidney. While the increase in total OAT activity was much more than the increase in kidney weight, all other enzymes increased more or less in proportion to the increase in renal mass. The results suggest that compensation in OAT activity to chronic reduction in renal mass was complete, but only partial in the case of other enzymes.     

Structural changes in hepatocytes during rheopolyglucine administration and subsequent stress in mice

A lysosomotropic agent rheopolyglucine was injected intravenously to male CBA mice at a dose of 1 ml per 100 g body weight. Two hours later hepatocyte hypertrophy and cytoplasmic organoid hyperplasia were observed. The exposure of these mice to acute stress did not lead to catabolic changes in hepatocytes.     

Conformational changes in DNA during development of spontaneous leukosis in AKR mice

The dynamics of conformational changes in thymus and spleen DNA of 3-9-month old mice line AKR during the development of spontaneous lymphoid leukosis was studied by the retention on nitrocellulose filters. It was shown that the degree of DNA condensation for healthy and deceased animals differs, which is probably due to different intensity of endogenous oxidation. Seasonal conformational changes in spleen DNA from healthy mice of line F1 were revealed.     

Hematological and acid-base changes in men during prolonged exercise with and without sodium-lactate infusion.

An emerging technique used for the study of metabolic regulation is the elevation of lactate concentration with a sodium-lactate infusion, the lactate clamp (LC). However, hematological and acid-base properties affected by the infusion of hypertonic solutions containing the osmotically active strong ions sodium (Na(+)) and lactate (Lac(-)) are a concern for clinical and research applications of LC. In the present study, we characterized the hematological and plasma acid-base changes during rest and prolonged, light- to moderate-intensity (55% Vo(2 peak)) exercise with and without LC. During the control (Con) trial, subjects were administered an isotonic, isovolumetric saline infusion. During LC, plasma lactate concentration ([Lac(-)]) was elevated to 4 meq/l during rest and to 4-7 meq/l during exercise. During LC at rest, there were rapid and transient changes in plasma, erythrocyte, and blood volumes. LC resulted in decreased plasma [H(+)] (from 39.6 to 29.6 neq/l) at the end of exercise while plasma [HCO(3)(-)] increased from 26 to 32.9 meq/l. Increased plasma strong ion difference [SID], due to increased [Na(+)], was the primary contributor to decreased [H(+)] and increased [HCO(3)(-)]. A decrease in plasma total weak acid concentration also contributed to these changes, whereas Pco(2) contributed little. The infusion of hypertonic LC caused only minor volume, acid-base, and CO(2) storage responses. We conclude that an LC infusion is appropriate for studies of metabolic regulation.     

Phenotypic changes of Helicobacter pylori components during an experimental infection in mice

The bacterial pathogen Helicobacter pylori is highly adapted to the human stomach and the clinical isolates show a high diversity which could be due to adaptative changes of the strains passing from one host to another. In order to study these variations, experimental infection of mice was developed and provided three out of the eleven tested strains able to infect C57BL/6 mice: the Sydney strain which is known to be well adapted to mice and two freshly isolated strains from infected patients. Mice were orally infected with one of these three strains (infecting strains) and were killed 45 days later. H. pylori strains were isolated from the stomachs of mice (emerging strains). The three infecting strains were compared to the three emerging strains for protein and lipopolysaccharide profiles, antigenic profiles revealed by Western blot with monospecific sera and genetic status by testing for the cagA gene and the vacA genotype. During the 45 days of infection, H. pylori underwent phenotypic variations which may be attributed to the adaptation from a human to a mouse environment or from an in vitro to a mouse environment. Those variations consisted of an over-expression at the cell surface of a 180-kDa protein and of a decreased expression of proteins of 260 and 120 kDa. Moreover, antigenic variations were shown for the two freshly isolated strains from human: the CagA and VacA antigens were in the saline extracts of the infecting strains only while the UreA, UreB, HspA and HspB were in the saline extracts of both the infecting and the emerging strains. These variations may contribute to the adaptation of the strains to the mouse environment.