Response of white mice to inoculation of irradiated organisms of the Toxoplasma strain RH

Chemotherapeutic agents available for use against toxoplasmosis are usually not suitable for prophylactic purposes because of their toxicity. The observed increasing number of activated latent infections with Toxoplasma, especially in immune suppressed patients, requires that safe techniques are available for use during the patient's regression period. Pretreatment of mice with Toxoplasma killed by irradiation appeared to induce resistance to challenge with virulent organisms. Survival times of six months have been observed to date. Increasing effectiveness was seen after more than one administration. Further investigation into the duration of effective resistance is needed; the question of at which intervals subsequent inoculations should be performed in order to acquire a booster effect, if any, has still to be solved before application to man can be recommended.     

Influence of ethanol and temperature on the cellular fatty acid composition of Zygosaccharomyces bailii spoilage yeasts

Changes in the fatty acid profile of Zygosaccharomyces bailii strains, isolated from different sources, after growth at increasing concentrations of ethanol and/or decreasing temperatures were determined. Differences in fatty acid composition between Zygosaccharomyces bailii strains at standard conditions (25°C, 0% initial ethanol) were observed and could be related to ethanol tolerance. Zygosaccharomyces bailii strain isolated from wine showed the highest ethanol tolerance in relation to growth rate. Surprisingly, an increase in ethanol concentration or a decrease in growth temperature caused a decrease in the degree of unsaturation of total cellular fatty acids. On the other hand, the mean chain length increased (high ethanol concentration) or decreased (low temperature) depending on the stress factor. When both stress situations (high ethanol concentration and low temperature) were present at the same time, the degree of unsaturation remained approximately constant. With decreasing temperatures, the C16/C18 ratio increased in studies of initial ethanol content below 5%, and above 5% ethanol, decreased.     

Factors and Models Associated with the amount of Hospital Care Services as Demanded by Hospitalized Patients: A Systematic Review

Background

Hospitals are constantly being challenged to provide high-quality care despite ageing populations, diminishing resources, and budgetary restraints. While the costs of care depend on the patients'' needs, it is not clear which patient characteristics are associated with the demand for care and inherent costs. The aim of this study was to ascertain which patient-related characteristics or models can predict the need for medical and nursing care in general hospital settings.

Methods

We systematically searched MEDLINE, Embase, Business Source Premier and CINAHL. Pre-defined eligibility criteria were used to detect studies that explored patient characteristics and health status parameters associated to the use of hospital care services for hospitalized patients. Two reviewers independently assessed study relevance, quality with the STROBE instrument, and performed data analysis.

Results

From 2,168 potentially relevant articles, 17 met our eligibility criteria. These showed a large variety of factors associated with the use of hospital care services; models were found in only three studies. Age, gender, medical and nursing diagnoses, severity of illness, patient acuity, comorbidity, and complications were the characteristics found the most. Patient acuity and medical and nursing diagnoses were the most influencing characteristics. Models including medical or nursing diagnoses and patient acuity explain the variance in the use of hospital care services for at least 56.2%, and up to 78.7% when organizational factors were added.

Conclusions

A larger variety of factors were found to be associated with the use of hospital care services. Models that explain the extent to which hospital care services are used should contain patient characteristics, including patient acuity, medical or nursing diagnoses, and organizational and staffing characteristics, e.g., hospital size, organization of care, and the size and skill mix of staff. This would enable healthcare managers at different levels to evaluate hospital care services and organize or reorganize patient care.     

Differential regulation of cell volume and shape in confluent rat hepatocytes under hypertonic stress.

In confluent primary cultures of rat hepatocytes,hypertonic stress leads to cell shrinkage and activates non-selective cation channels as the main mechanism of regulatory cell volume increase. The process is found to employ the exocytotic insertion of channels into the plasma membrane and (in addition to PKC) PLC, tyrosine kinases and G proteins, but not PI 3-kinase are part of the signalling network. Furthermore, hypertonic stress leads to the formation of stress fibres and significantly alters the activity of RhoA, Rac and Cdc42. These latter effects, however, are likely to reflect the restoration of cell shape rather than the regulation of cell volume, both most probably converging at the level of focal adhesions and integrins.     

Recapitulation of embryonic neuroendocrine differentiation in adult human pancreatic duct cells expressing neurogenin 3

Regulatory proteins have been identified in embryonic development of the endocrine pancreas. It is unknown whether these factors can also play a role in the formation of pancreatic endocrine cells from postnatal nonendocrine cells. The present study demonstrates that adult human pancreatic duct cells can be converted into insulin-expressing cells after ectopic, adenovirus-mediated expression of the class B basic helix-loop-helix factor neurogenin 3 (ngn3), which is a critical factor in embryogenesis of the mouse endocrine pancreas. Infection with adenovirus ngn3 (Adngn3) induced gene and/or protein expression of NeuroD/beta2, Pax4, Nkx2.2, Pax6, and Nkx6.1, all known to be essential for beta-cell differentiation in mouse embryos. Expression of ngn3 in adult human duct cells induced Notch ligands Dll1 and Dll4 and neuroendocrine- and beta-cell-specific markers: it increased the percentage of synaptophysin- and insulin-positive cells 15-fold in ngn3-infected versus control cells. Infection with NeuroD/beta2 (a downstream target of ngn3) induced similar effects. These data indicate that the Delta-Notch pathway, which controls embryonic development of the mouse endocrine pancreas, can also operate in adult human duct cells driving them to a neuroendocrine phenotype with the formation of insulin-expressing cells.     

Comparison of faecal Lactobacillus populations in experimental animals from different breeding facilities and possible consequences for probiotic studies

AIMS: The effect of probiotic lactobacilli is likely dependent on the indigenous Lactobacillus strains in the intestinal tract. Since a substantial number of probiotic studies is performed in rodents, we compared the Lactobacillus strains of different rat and mouse populations in three animal facilities. METHODS AND RESULTS: SDS-PAGE and 16S rDNA analysis of cultured faecal lactobacilli revealed that different Lactobacillus strains were detected in genetically similar Wistar rats bred at different locations. Further, within the same animal facility host genetics did not affect the types of the predominant lactobacilli strains. CONCLUSIONS: Our results show that the environmental background of laboratory animals rather than host genetics determines the indigenous Lactobacillus strains that are found. SIGNIFICANCE AND IMPACT OF THE STUDY: Our findings underline the importance of microflora analysis in probiotic studies.     

Cascade synthesis of chiral block copolymers combining lipase catalyzed ring opening polymerization and atom transfer radical polymerization

The enantioselective polymerization of methyl-substituted epsilon-caprolactones using Novozym 435 as the catalyst was investigated. All substituted monomers could be polymerized except 6-methyl-epsilon-caprolactone (6-MeCL), which failed to propagate after ring opening. Interestingly, an odd-even effect in the enantiopreference of differently substituted monomers was observed. The combination of 4-methyl-epsilon-caprolactone with Novozym 435 showed good enantioselectivity also in bulk polymerization and resulted in enantiomerically enriched P((S)-4-MeCL) (eep up to 0.88). Subsequently, a novel initiator combining a primary alcohol to initiate the ring opening polymerization and a tertiary bromide to initiate atom transfer controlled radical polymerization (ATRP) was synthesized, and showed high initiator efficiencies (> 90%) in the ring opening polymerization of 4-methyl-epsilon-caprolactone in bulk. In addition, the enantioselectivity was retained (E = 11). By using Ni(PPh3)2Br2 as the ATRP catalyst, Novozym 435 could be effectively inhibited at the desired conversion of 4-methyl-epsilon-caprolactone, thus ensuring a high enantiomeric excess in the polymer backbone. At the same time, Ni(PPh3)2Br2 catalyzed the ATRP of methyl methacrylate resulting in the formation of P((S)-4-MeCL-b-MMA) block copolymers. By this combination of two inherently different polymerization reactions, chiral P((S)-4-MeCL-b-MMA) block copolymers can be conveniently obtained in one pot without intermediate workup.     

A novel hypertonicity-induced cation channel in primary cultures of human hepatocytes

In whole-cell recordings on primary cultures of human hepatocytes, we observe the hypertonic activation of a novel type of cation channel with a permeability ratio for Na(+):Li(+):K(+):Cs(+):NMDG(+) of 1:1.2:1.3:1.2:0.6. With a P(Ca)/P(Na) of 0.7 the channel is also clearly permeable to Ca(++). Most likely, the channel is Cl(-) impermeable but its activity critically depends on the extracellular Cl(-) concentration (with the half maximal effect at 88 mmol/l). With a 64% inhibition by amiloride and a complete block by flufenamate and Gd(3+) (at 100 micromol/l each), the channel may represent a molecular link between the amiloride-sensitive and insensitive channels reported so far.     

Use of 8-hydroxyquinoline-beta-D-glucuronide for presumptive identification of Shiga toxin-producing Escherichia coli O157

8-hydroxyquinoline-beta-D-glucuronide (HQG) was used to improve the presumptive identification of Shiga toxin-producing Escherichia coli O157 (STEC O157) on sorbitol MacConkey agars (SMAC). Advantages of HQG are (i) that it is less expensive than 5-bromo-4-chloro-3-indoxyl-glucuronide; (ii) that it is visible in normal daylight and (iii) that it does not diffuse into the agar like 4-methylumbelliferryl-beta-D-glucuronide (MUG). Sixteen STEC O157 isolates, 91 bovine mastitis-associated E. coli isolates and 222 faecal E. coli isolates from apparently healthy cattle were used in this study. 4-methylumbelliferryl-beta-D-glucuronide detected beta-glucuronidase activity in more isolates than HQG (P < 0.05). On SMAC with HQG, cefixime and tellurite all STEC O157 isolates grew as cream-coloured colonies (100% sensitivity), whereas all non-STEC O157 E. coli except one grew either not at all or as purple or black colonies (99.7% specificity). No difference was found between faecal and mastitis isolates for the proportion of isolates that hydrolysed HQG or MUG or fermented sorbitol. However, significantly more mastitis isolates were able to grow in the presence of the cefixime-tellurite supplement. 8-Hydroxyquinoline-beta-D-glucuronide is a useful substrate for the identification of STEC O157 on SMAC.