POstLAparoscopic Reduction of pain By combining intraperitoneal normal salinE And the pulmonary Recruitment maneuver (POLAR BEAR trial). RCT to estimate reduction in pain after laparoscopic surgery when using a combination therapy of intraperitoneal normal saline and the pulmonary recruitment maneuver.

BACKGROUND: Shoulder pain and pain in the upper abdomen are common complaints after laparoscopy, sometimes surpassing the pain at incision sites. The incidence of shoulder pain ranges from 35 to 80%. Post-laparoscopic pain is caused by retention of carbon dioxide in the abdomen, which irritates the phrenic nerve and diaphragm, causing referred pain in the shoulder and in the upper abdomen. A promising strategy to reduce this post-laparoscopic pain is the pulmonary recruitment maneuver, which indirectly increases intraperitoneal pressure and thereby facilitates removal of residual carbon dioxide. An alternative strategy is the infusion of intraperitoneal normal saline. With normal saline infusion, carbon dioxide rises and escapes through the port sites. In addition, normal saline offers a physiologic buffer system to dissolve excess carbon dioxide. METHODS/DESIGN: This multicenter randomized controlled trial is conducted in two teaching hospitals in the Netherlands. Women between 18 and 65 years of age, with an ASA classification of I-II who are scheduled to undergo an elective laparoscopic procedure with benign gynecologic indication can participate. Following informed consent, participants are randomly allocated into two groups at the end of the surgical procedure. In the intervention group, the upper abdomen is filled with normal saline infusion with the patient in the Trendelenburg position. Then the anesthesiologist performs a standardized pulmonary recruitment maneuver with a pressure of 40 cm H2O. The trocar sleeve valves will be left open, so carbon dioxide can escape the abdominal cavity. With the patient in a neutral position the instruments are removed from the abdomen. In the control group, carbon dioxide is removed from the abdominal cavity at the end of surgery, with gentle abdominal pressure and passive exsufflation through the port sites, with open sleeve valves. The primary outcomes are the incidence and intensity of post-laparoscopic pain in the shoulder, upper abdomen and at the operation sites, at 8, 24 and 48 h after surgery. Secondary outcomes are postoperative use of analgesics, nausea, vomiting and pulmonary complications. DISCUSSION: This study may reduce post-laparoscopic pain in women undergoing laparoscopy. TRIAL REGISTRATION: Dutch trial register, number NTR4812 .

Microbial products from probiotic bacteria inhibit Salmonella enteritidis 857-induced IL-8 synthesis in Caco-2 cells.

Oral administration of Lactobacillus spp. as probiotics is gaining importance in the treatment of intestinal inflammations. However, their mechanism of action is unknown. We investigated whether nonspecific binding Lactobacillus casei Shirota (LcS) and mannose-specific Lactobacillus plantarum 299v (Lp) and their spent culture supernatant (SCS) affect Salmonella enteritidis 857 (Se) growth, IL-8 and Hsp70 syntheses. In one set of experiments human enterocyte-like Caco-2 cells were infected with LcS, Lp or Se at 1-500 bacteria per cell for 1 h. In another set, cells were exposed to Se (0-200 per cell, 1 h) after exposure to lactobacilli (LB) (500 per cell, 30 min) or by co-incubation of Se and LB (1 h). The third set of experiments involved exposure of cells for 1 h to SCS or Se (100 per cell) pretreated (1 h) in SCS. The effect of LB SCS on Se growth was evaluated by agar plate diffusion test. IL-8 and Hsp70 were assessed over 2-24 h using ELISA and Western blotting, respectively. Neither LcS nor Lp affected the Se growth and IL-8 production. In addition, they did not induce Hsp70 expression by Caco-2 cells. Instead, their SCS inhibited the Se growth and IL-8 production and induced the expression of Hsp70 by both crypt- and villus-like cells. The beneficial effect of Lactobacillus spp. to the intestinal inflammations might be associated with a decrease in IL-8 levels. This effect could be mediated, at least in part, via a secreted antimicrobial product(s) either directly against the pathogens or indirectly through the synthesis of Hsp70.

Assessment of thyroid function in dogs with low plasma thyroxine concentration.

BACKGROUND: Differentiation between hypothyroidism and nonthyroidal illness in dogs poses specific problems, because plasma total thyroxine (TT4) concentrations are often low in nonthyroidal illness, and plasma thyroid stimulating hormone (TSH) concentrations are frequently not high in primary hypothyroidism. HYPOTHESIS: The serum concentrations of the common basal biochemical variables (TT4, freeT4 [fT4], and TSH) overlap between dogs with hypothyroidism and dogs with nonthyroidal illness, but, with stimulation tests and quantitative measurement of thyroidal 99mTcO4(-) uptake, differentiation will be possible. ANIMALS: In 30 dogs with low plasma TT4 concentration, the final diagnosis was based upon histopathologic examination of thyroid tissue obtained by biopsy. Fourteen dogs had primary hypothyroidism, and 13 dogs had nonthyroidal illness. Two dogs had secondary hypothyroidism, and 1 dog had metastatic thyroid cancer. METHODS: The diagnostic value was assessed for (1) plasma concentrations of TT4, fT4, and TSH; (2) TSH-stimulation test; (3) plasma TSH concentration after stimulation with TSH-releasing hormone (TRH); (4) occurrence of thyroglobulin antibodies (TgAbs); and (5) thyroidal 99mTcO4(-) uptake. RESULTS: Plasma concentrations of TT4, fT4, TSH, and the hormone pairs TT4/TSH and fT4/TSH overlapped in the 2 groups, whereas, with TgAbs, there was 1 false-negative result. Results of the TSH- and TRH-stimulation tests did not meet earlier established diagnostic criteria, overlapped, or both. With a quantitative measurement of thyroidal 99mTcO4(-) uptake, there was no overlap between dogs with primary hypothyroidism and dogs with nonthyroidal illness. CONCLUSIONS AND CLINICAL IMPORTANCE: The results of this study confirm earlier observations that, in dogs, accurate biochemical diagnosis of primary hypothyroidism poses specific problems. Previous studies, in which the TSH-stimulation test was used as the "gold standard" for the diagnosis of hypothyroidism may have suffered from misclassification. Quantitative measurement of thyroidal 99mTcO- uptake has the highest discriminatory power with regard to the differentiation between primary hypothyroidism and nonthyroidal illness.

Endocrine intervention during irradiation does not prevent damage to the thyroid gland.

Radiation to the head-neck region may damage the thyroid gland, leading to hypothyroidism or thyroid carcinoma. Outcomes of radiation protection by lowering plasma thyroid-stimulating hormone (TSH) have thus far been ambiguous. Our aim was to evaluate the radioprotective effect of inhibiting the thyroid gland's activity during x-radiation. For this purpose, of 80 5-week old Wistar rats, 64 received cervical irradiation with 15 Gy (single dose). During irradiation, endocrine intervention was done, using thyroxine (T(4)), T(4) plus iodine, or iodine alone compared to placebo. During the endocrine interventions and follow-up, TSH and T(4) concentrations were measured periodically. Histologic examination of thyroid, pituitary gland, or the hypothalamus and any suspect lymph nodes, lungs, and liver was performed after 6 and 54 weeks. It was found that during the endocrine intervention, plasma levels of TSH were lower in rats given T(4) and higher in rats given iodine. After 6 and 54 weeks, no significant reduction in hypothyroidism or thyroid carcinoma was found between the different groups of rats given any endocrine intervention or no intervention. In conclusion, the administration of T(4), iodine or the combination during x-irradiation does not protect against radiation-induced thyroid damage.

Indomethacin disrupts the protective effect of phosphatidylcholine against bile salt-induced ileal mucosa injury.

BACKGROUND: Indomethacin (Indo) exerts local toxic effects on small intestinal mucosa, possibly in association with hydrophobic bile salts. We investigated the potential toxic effects of Indo on ileal mucosa and the role of phosphatidylcholine (PC). MATERIALS AND METHODS: Transmucosal resistance and Na-fluorescein permeability of ileal mucosa segments from female Wistar rats were determined in Ussing chambers during a 30-min incubation with model systems containing: control-buffer, taurodeoxycholate (TDC), Indo, TDC-Indo, TDC-PC, or TDC-PC-Indo. Decrease of resistance and increase of permeability were considered as parameters for mucosal injury. After incubation in Ussing chambers, the histopathology was examined to quantify the extent of mucosal injury. Also, in CaCo-2 cells, LDH-release was determined as a measure of cytotoxicity, after incubation with various model systems. RESULTS: Decrease of resistance and increase of permeability were highest in systems containing TDC-Indo (P < 0.01). Phosphatidylcholine protected against the cytotoxic effects of TDC in absence of Indo only. Extent of mucosal injury by histological examination was also highest in systems containing TDC-Indo (P = 0.006). Again, PC exhibited protective effects in absence of Indo only. The LDH-release by CaCo2-cells was strongest in TDC-Indo systems (P < 0.001). CONCLUSIONS: Indomethacin disrupts protective effects of PC against bile salt-induced ileal mucosa injury. This finding is relevant for small intestinal injury induced by non-steroidal anti-inflammatory drugs.

Partial purification and characterization of ferritin from the liver and intestinal mucosa of chickens, turtledoves and mynahs.

Ferritin is the iron-storage protein responsible for sequestering excess iron, to be stored in a safe way in the liver or to be shed with the intestinal epithelial cells. The properties of ferritin in iron-overload-susceptible birds have not been elucidated. Furthermore, there is only scarce information on mucosal ferritin, with no information at all in avian species. Here we have studied the liver and proximal intestine ferritins of iron-overload-susceptible (Indian hill mynahs, common mynahs) and non-susceptible (turtledoves, chicken) bird species. A brief purification process preceded native polyacrylamide gel electrophoresis and staining the gels for protein and iron. Protein amounts and iron-binding characteristics of ferritin were measured and ferritin saturation levels were calculated. Although ferritin protein amounts did not differ significantly, liver and mucosal ferritins of sensitive bird species incorporated much more iron, leading to high saturation levels. Significantly higher ferritin iron content and saturation were observed in the liver of both mynah species and in the intestinal ferritin of Indian hill mynahs when compared with the non-susceptible species. Ferritin appears not to play a major role in the regulation of iron absorption, implicating other phases in iron transport to be more important in the onset and process of iron overload in birds.

Probiotic effects of Lactobacillus casei on DSS-induced ulcerative colitis in mice.

We tested the effect of Lactobacillus casei strain Shirota (LcS) on the murine model of ulcerative colitis induced by dextran sodium sulphate. The effect of LcS was tested either as a prophylactic 10 days before the onset of the disease, simultaneously with ulcerative colitis induction or continued 10 days after the disease was induced. LcS was not able to prevent the disease induction in any of the experiments. However, important clinical parameters including blood anemia indicators, body weight, and organ weight were improved in the animals receiving LcS as compared with the ulcerative colitis-induced controls. Increased colonic epithelial regeneration in the LcS treated animals was observed in the chronic stage. The results seemed better for the simultaneous short LcS treatment where some parameters remained similar to the PBS controls, including disease activity scores measured in the acute stage. We can conclude that although LcS alone cannot prevent the induction of ulcerative colitis by dextran sodium sulphate, it can improve the clinical condition of the mice. This could imply important biological consequences for the human situation. Further studies including LcS or other probiotic bacteria together with the available treatment are encouraged.

Expression of versican in relation to chondrogenesis-related extracellular matrix components in canine mammary tumors.

Versican plays a role in tumor cell proliferation and adhesion and may also regulate cell phenotype. Furthermore, it is one of the pivotal proteoglycans in mesenchymal condensation during prechondrogenesis. We have previously demonstrated accumulation of versican protein in myoepithelial-like spindle cell proliferations and myxoid tissues of complex and mixed mammary tumors of dogs. The objective of this study was to investigate whether the high expression of versican relates to prechondrogenesis in these tissues. Therefore, we aimed to identify cartilage markers, such as collagen type II and aggrecan both at mRNA and protein level in relation to versican. The neopitope of chondoitin-6-sulphate (3B3) known to be generated in developing cartilage has been investigated by immunohistochemisty and a panel of antibodies were used to characterize the phenotype of cells that are involved in cartilage formation. In addition, co-localization of versican with hyaluronan and link protein was studied. RT-PCR revealed upregulation of genes of versican, collagen type II and aggrecan in neoplastic tissues, especially in complex and mixed tumors. Immunohistochemistry showed the expression of cartilage biomarkers not only in the cartilagenous tissues of mixed tumors, but also in myoepitheliomas and in the myoepithelial-like cell proliferations and myxoid areas of complex and mixed tumors. The results show the cartilagenous differentiation of complex tumors and myoepitheliomas and indicate that the myxoid tissues and myoepithelial-like cell proliferations are the precursor tissues of the ectopic cartilage in mixed tumors. Furthermore, we suggest that cartilage formation in canine mammary tumors is a result of (myo)epithelial to mesenchymal transition.

Galectins as markers of aggressiveness of mouse mammary carcinoma: towards a lectin target therapy of human breast cancer.

Galectins, beta-galactoside binding proteins, expressed selectively in human breast carcinoma are attractive targets to employ lectin-aimed therapeutics. We examined beta-galactoside binding potency of neoplastic cells using fluorescein-labelled synthetic glycoconjugates as probes for flow cytometry. As a result, surface beta-galactoside binding proteins/galectins were discovered on mouse mammary carcinoma cells in vitro and in vivo unlike non-malignant cells from the several tissues; and asialo-GM1 ganglioside carbohydrate part--containing probe was the most specific one. However, in liver and lung metastatic cells galectins seem to be expressed within cytoplasm and/or nuclei. Galectin expression correlated directly with aggressive tumour potential in the A/Sn transplantable model similar to findings in several human breast carcinoma cell lines. However, galectin expression was reduced during tumour progression in more aggressive forms of spontaneous BLRB mammary carcinomas like it was shown for human breast carcinoma specimens. Analysis of the histopathological data led, however, to the conclusion that galectin expression hardly might be a suitable marker of aggressiveness of heterogeneous mammary carcinomas as the observed level of galectin expression is influenced by the amount of the stroma in a tumour sample and/or probably, galectin expression inversely correlates with tumour aggressiveness during the initial and advanced steps of mammary tumour progression. We conclude that surface beta-galactoside binding proteins/galectins that are selectively expressed during mouse mammary carcinoma progression, similarly to human breast carcinomas, seem to be proper targets for asialo-GM1-vectored cytotoxics and our mouse model system might be a relevant instrument to further test novel modes of anti-breast cancer therapy.

The effect of cervical X-irradiation on activity index of thyrocytes and plasma TSH: a pre-clinical model for radiation-induced thyroid damage.

Because radiotherapy in the head and neck region is necessary in the treatment of childhood cancer, possibilities to prevent damage to the thyroid gland must be explored. We developed a model in which radiation-induced effects can be investigated in a way that these effects can be quantified, using thyroid dysmorphology and plasma TSH. Thirty-five Wistar rats, 5 weeks old, were X-irradiated on the cervical region, with a single dose varying from 0 to 20 Gy. After 6 weeks, TSH, T4 and T3 were determined, and thyroid glands were processed for histological examination by two independent pathologists. A histological classification scale was developed, using follicular size, colloid density and cell height of thyrocytes to measure hyperplasia and hypertrophy. By the sum of these scores, a cell-activity index was calculated, which was related to plasma TSH concentration. Numbers of PAS-positive droplets and epithelial desquamation were also counted. Inter-observer reliability was assessed. Good to very good reliability was found for scores of follicular size, colloid density and cell height. Significant increase of cell-activity index was found after 10, 15 and 20 Gy. The plasma TSH concentration was positively correlated to the cell-activity index, increasing with radiation-doses up to 15 Gy. The number of desquamated cells was significantly increased after radiation doses >10 Gy, with moderate reliability. In conclusion, this model using cell-activity index of thyrocytes together with plasma thyrotropin concentrations and desquamation of cells can be used for interpretation and future (pre-clinical) studies of prevention of radiation-induced thyroid damage.

Anti-inflammatory properties of heat shock protein 70 and butyrate on Salmonella-induced interleukin-8 secretion in enterocyte-like Caco-2 cells.

Intestinal epithelial cells secrete the chemokine interleukin (IL)-8 in the course of inflammation. Because heat shock proteins (Hsps) and butyrate confer protection to enterocytes, we investigated whether they modulate Salmonella enterica serovar Enteritidis (S. serovar Enteritidis)-induced secretion of IL-8 in enterocyte-like Caco-2 cells. Caco-2 cells incubated with or without butyrate (0-20 m M, 48 h) were infected with S. serovar Enteritidis after (1 h at 42 degrees C, 6 h at 37 degrees C) or without prior heat shock (37 degrees C). Levels of Hsp70 production and IL-8 secretion were analysed using immunostaining of Western blots and enzyme-linked immunosorbent assay (ELISA), respectively. The cells secreted IL-8 in response to S. serovar Enteritidis and produced Hsp70 after heat shock or incubation with butyrate. The IL-8 secretion was inhibited by heat shock and butyrate concentrations as low as 0.2 m M for crypt-like and 1 m M for villous-like cells. In a dose-dependent manner, higher butyrate concentrations enhanced IL-8 secretion to maximal levels followed by a gradual but stable decline. This decline was associated with increasing production of Hsp70 and was more vivid in crypt-like cells. In addition, the higher concentrations abolished the heat shock inhibitory effect. Instead, they promoted the IL-8 production in heat-shocked cells even in the absence of S. serovar Enteritidis. We conclude that heat shock and low concentrations of butyrate inhibit IL-8 production by Caco-2 cells exposed to S. serovar Enteritidis. Higher butyrate concentrations stimulate the chemokine production and override the inhibitory effect of the heat shock. The IL-8 down-regulation could in part be mediated via production of Hsp70.

Iron metabolism in mynah birds (Gracula religiosa) resembles human hereditary haemochromatosis.

Iron overload is a very frequent finding in several animal species and a genetic predisposition is suggested. In one of the most commonly reported species with susceptibility for iron overload (mynah bird), it was recently shown that the cause of this pathophysiology is high uptake and retention of dietary iron. Here we compare susceptible (mynahs) with non-susceptible avian species (chickens) by evaluating iron uptake at the intestinal absorptive cell level. Enterocytes from mynahs and chickens were isolated and uptake of Fe(II) and Fe(III) was studied in vitro. It was found that Fe(III) uptake is much lower than Fe(II) uptake for both species. Although liver iron, present only in hepatocytes, was at least 10-fold higher in mynahs than chickens, enterocyte Fe(II) uptake was considerably higher in mynahs. Fe(II) uptake showed saturation at the studied concentrations in both species. Kinetic studies revealed a three-fold increase in Vmax for mynahs. Calculated values for the uptake kinetics of the probable membrane transporter suggest that mynah bird enterocytes have a significantly higher limiting uptake rate, due to the possible increase in the number of transporters when compared with chicken enterocytes. The susceptibility of this species is due to intestinal iron uptake despite hepatic iron accumulation, implicating a 'mis-sensing' of body iron similarly to human hereditary haemochromatosis.

Immunohistochemical evaluation of versican, in relation to chondroitin sulphate, in canine mammary tumours.

The expression of increased amounts of versican, a chondroitin sulphate proteoglycan, in neoplastic tissues may play a role in promoting tumour cell proliferation and migration. This study investigated the immunolocalization of versican in normal and neoplastic canine mammary tissues, using antibodies 12C5 and 2B1, against different epitopes of the protein core of versican. Antibody CS56, recognising chondroitin sulphate (CS), was used to investigate the relation between versican and CS, which accumulates in canine mammary tumours. We found enhanced versican expression in both benign and malignant tumours, appearing in three main patterns: in periductal tissues, probably in association with basement membranes of ducts; in peripheral invasive areas of malignant tumours; and in spindle cell proliferations and myxoid areas of complex and mixed tumours. The 12C5 and 2B1 immunoreactivities co-localised in all types of tumours, and could be improved by chondroitinase digestion. The only exception was the abundant extracellular matrix (ECM) of spindle cell proliferations, particularly in myxoid areas of complex and mixed tumours, which displayed intense and diffuse 12C5 immunoreactivity and patchy or absent 2B1 and CS56 immunoreactivities; versican immunoreactivity could not be enhanced by chondroitinase digestion. The results indicate that versican is one of the extracellular matrix components characteristic of canine mammary tumours. It appears likely that in complex and mixed tumours versican exists in at least two forms, one of them lacking the CS attachment domain and the 2B1 epitope. Furthermore, the enhanced versican expression in the invasive areas of malignant tumours indicates the involvement of this proteoglycan in tumour cell invasion.

Differential modulation of enterocyte-like Caco-2 cells after exposure to short-chain fatty acids.

The response of intestinal epithelial cells to short-chain fatty acids, which are increasingly used as food additives, was investigated. Human small intestinal epithelial cell model Caco-2 cells were exposed to formate, propionate and butyrate to assess their effect on cellular growth, metabolism, differentiation and protection against bacteria. The Caco-2 cells were entirely grown in the different short-chain fatty acids and respective growth patterns were determined. Differentiated cells were exposed to 0-20 mM short-chain fatty acids for 48 h and changes in DNA, RNA, (glyco)protein syntheses, sucrase isomaltase activity, transepithelial electrical resistance and protection against Salmonella enteritidis were measured. The short-chain fatty acids, altered linearly and differentially the growth pattern ranging from stimulation by formate to inhibition by butyrate. Formate inhibited cellular metabolism. Low concentrations of up to 5 mM propionate and 2 mM butyrate stimulated metabolism, while higher doses were inhibitory. Formate had no effect on sucrase isomaltase enzyme activity and transepithelial electrical resistance, whereas propionate and butyrate increased these markers of differentiation. Infection with S. enteritidis did not benefit from the short-chain fatty acid-induced transepithelial electrical resistance. It is concluded that formate, propionate and butyrate selectively and differentially modulate growth characteristics, cellular metabolism, sucrase isomaltase activity and transepithelial electrical resistance in a concentration- and carbon atom-related fashion. The short-chain fatty acid-induced transepithelial electrical resistance does not confer protection against S. enteritidis.

Factors involved in the early pathogenesis of bovine Staphylococcus aureus mastitis with emphasis on bacterial adhesion and invasion. A review.

Staphylococcus aureus is the most important and prevalent contagious mammary pathogen; it causes clinical and subclinical intramammary infection with serious economic loss and herd management problems in dairy cows. In vitro studies have shown that Staphylococcus aureus adheres to mammary epithelial cells and extracellular matrix components and invades into mammary epithelial as well as other mammary cells. Staphylococcus aureus strains from intramammary infection produce several cell surface-associated and extracellular secretory products. The exact pathogenic roles of most of the products and their effects on adhesion and invasion are not well evaluated. It is also known that mammary epithelial cell-associated molecules and extracellular matrix components interact with S. aureus during the pathogenesis of mastitis, but their roles on adhesion and invasion have not been characterized. The adhesion of S. aureus to epithelial cells may involve non-specific physicochemical interactions and/or specific interactions between bacterial cell-associated ligands and host cell surface receptors. In vitro adhesion depends on the S. aureus strain, the growth phase of the bacteria, the growth medium and the origin of the epithelial cells. Adhesion is hypothesized to be a prerequisite and crucial early step for mammary gland infection. Staphylococcus aureus invades mammary epithelial cells. It also invades other cells such as endothelial cells and fibroblasts. Bacteria are found enclosed in membrane bound vacuoles in the cytoplasm of mammary epithelial cells. Recent observations indicate that S. aureus escapes from the phagosome into the cytoplasm and induces apoptosis. The invasion into mammary epithelial cells may occur through an endocytic process that requires involvement of elements of the cytoskeleton or by direct binding of bacteria to epithelial cells through a process mediated by specific receptors that needs de novo protein synthesis by both cells. Thus, the recurrent subclinical infection may result from this intracellular existence of bacteria that are protected from host defenses and effects of antibiotics. This review emphasizes on recent findings on S. aureus adhesion to mammary epithelial cells and extracellular matrix components and invasion into mammary epithelial cells.

Behavioral and physiological effects of biotechnology procedures used for gene targeting in mice.

The effects of gene-targeting procedures on the behavior and physiological development of (chimeric) mice have been investigated. We used six groups of mice, each of them undergoing specific aspects of the biotechnological procedure, including electroporation, microinjection, and/or blastocyst culture. Changes in behavior and physiological development of the progeny (age 4-30 weeks) were investigated. Besides increased body weights, no significant difference between the six treatment groups and untreated C57BL/6 controls could be attributed to the biotechnology procedures. Therefore, we conclude that these procedures per se do not induce significant discomfort for the offspring. Differences in behavior, observed for the two groups of chimeric mice [one derived from electroporated embryonic stem (ES) cells and the other from nonelectroporated ES cells] when compared to the other (nonchimeric) groups, are, at least partly, due to the genetic background of the 129/Ola strain from which the ES cells are derived rather than to the biotechnological manipulations of the ES cells and/or blastocysts. The occurrence of hermaphrodites (8%) and some other gross pathologies observed in both groups of chimeric animals seem to indicate that developmental problems may occur when cells from different origin are simultaneously contributing to the development of one individual. This implies that during the production of gene-targeted mice, health and welfare of chimeric animals must be carefully monitored.

Assessment of vestibular schwannoma growth: application of a new measuring protocol to the results of a longitudinal study.

This study pertains to a group of 44 patients with unilateral vestibular schwannoma who did not undergo surgery. Prospectively, the dimensions of the tumor were depicted at regular intervals by means of magnetic resonance imaging and then judged independently by an otolaryngologist and a neuroradiologist. Retrospectively, the size of the tumor was quantified by measuring the maximum surface of the lesion in the axial plane. The retrospective surface measurements confirmed the assessments made in the prospective part of the study: growth in 18% of the patients and shrinkage in 7%; 75% remained unchanged. This approach is a pragmatic means to determine whether the size of a tumor has changed over the course of time.

Vestibular schwannoma: negative growth and audiovestibular features.

At the University Medical Center Utrecht, non-operative management was used for 44 patients with a unilateral vestibular schwannoma between 1990 and 1997. During that period, consecutive tumor sizes were determined by magnetic resonance imaging. Three of the 44 patients showed an average decrease in tumor size of 16.7% according to American Academy of Otolaryngology-Head and Neck Surgery standards. This study describes the initial vestibular status and audiometric changes measured over up to 10 years in these three patients. Vestibular function was determined once, by means of the bithermal caloric test, the torsion test, the saccade test, the smooth pursuit test, and the registration of spontaneous nystagmus. The three patients had severe vestibular paresis on the affected side. Pure-tone and speech audiometry were performed at regular intervals. Although the size of their tumors decreased, their hearing gradually deteriorated, just as it does in the majority of patients with a growing or stable vestibular schwannoma. The observations presented here suggest that the development of symptoms in a vestibular schwannoma does not differentiate between patients with a stable, growing or shrinking tumor. The development of symptoms may be the result of the same pathogenetic mechanism.

Obstructive jaundice, bacterial translocation and interdigestive small-bowel motility in rats.

BACKGROUND/AIMS: Translocation of gut bacteria occurs in obstructive jaundice, the underlying mechanisms are unclear. We designed this experimental study to investigate the association between interdigestive motility and the pathogenesis of bacterial translocation during biliary obstruction. METHODS: Rats were fitted with jejunal myoelectrodes for the measurement of the interdigestive migrating motor complex (MMC) and with two cannulas in the proximal common bile duct (CBD) for exteriorization of biliary flow. This allowed measurement of MMCs under control conditions with an intact enterohepatic circulation and during 3 days of CBD obstruction without surgical intervention. Mesenteric lymph nodes, liver, spleen and segments of the duodenum, the jejunum and the caecum were removed for microbial culturing. RESULTS: The MMC cycle length increased from 17.3 min before CBD obstruction to 31.9, 34.1, and 25.3 min on days 1, 2 and 3, respectively, after CBD obstruction (p < 0.05 for all days). Bacterial levels in the jejunum were significantly higher in CBD-obstructed rats than in control rats. The translocation incidence was significantly higher in rats with CBD obstruction (6/8) than in control rats (1/8). The bacterial levels in the jejunum correlated significantly with the MMC cycle length (r = 0.60, p <0.05). CONCLUSION: Experimental biliary obstruction is associated with disturbance of MMCs, small-bowel bacterial overgrowth and increased bacterial translocation.

Acoustic neuroma: deterioration of speech discrimination related to thresholds in pure-tone audiometry.

Pure-tone and speech audiometry were performed in 231 patients with a unilateral acoustic neuroma. Tumor sizes were obtained through imaging. Audiometric parameters, such as the mean pure-tone thresholds, the maximum discrimination, the slope of the speech audiogram, the roll-over index and the difference between the speech reception threshold and the Fletcher index, were studied and compared with data in the literature. Results showed that patients with an acoustic neuroma have worse speech discrimination than can be expected from the pure-tone audiogram. However, the results presented here indicate that hearing impairments nowadays are not as severe as those described in earlier studies. More patients with a unilateral acoustic neuroma are detected, including even those with a minor hearing impairment. The roll-over index is not characteristic for patients with an acoustic neuroma.