Effects of using mixed wine yeast cultures in the production of Chardonnay wines

The effect of using mixed cultures of non-Saccharomyces and Saccharomyces cerevisiae yeasts in the physicochemical and sensory qualities of the wines were analyzed in this study. Based on growth curves, sugar consumption and glycerol production in synthetic must, Candida membranifaciens L1805 was selected from a group of four Candidas spp. isolates from Chile and Argentina. This yeast was subsequently used in combination with S. cerevisiae in Chardonnay must. A monoculture of S. cerevisiae was used as control. The wines fermented with mixed cultures had lower volatile acidity and ethanol concentration than the control. Furthermore, the chromatographic analysis showed that the wines from mixed cultures presented differences in the concentration of esters and propanol. These characteristics positively influenced the sensory qualities of the wines produced with mixed cultures, which was reflected in the preference for these wines by a panel of enologists. This study shows that the use of non-Saccharomyces yeasts could be a strategy to obtain distinctive wines using the native microorganisms from each winemaking area.

Biomechanical evaluation of proximal tibia behaviour with the use of femoral stems in revision TKA: an in vitro and finite element analysis

BACKGROUND

Recognized failure mechanisms after revision total knee arthroplasty include failure of fixation, instability and loosening. Thus, extended stems have been used to improve fixation and stability. In clinical cases where the stem is only applied in the femur, a question concerning the structural aspect of tibia may arise: Does a stemmed femur changes the structural behaviour of proximal tibia? It seems, that question has not yet been fully answered and the use of stems in the opposite bone structure requires further analysis.

METHODS

Proximal cortex strains were measured with tri-axial strain gauges in synthetic tibias for three different types of implanted femurs, with two constrained implants. To assess the strains at the cancellous bone under the tibial tray, it was considered a closest physiological load condition with the use of finite element models.

FINDINGS

No significant differences of the mean of the tibial cortex strains for the stemmed femur relatively to the stemless femur were observed. The R(2) and slopes values of the linear regressions between experimental and finite element strains were close to one indicating good correlations. The strain behaviour of cancellous bone under the tibial tray is not completely immune to the use of femoral stem extensions. However, the level of this alteration is relatively small when compared with the strain magnitudes.

INTERPRETATION

The main insight given by the present study could probably lie in the fact that the use of femoral stems does not contribute to an increase of the risk of failure of the tibia.

Revision total knee arthroplasty: the influence of femoral stems in load sharing and stability

Restoration of lost bone support and joint stability are the primary challenges in revision total knee arthroplasty (TKA). Normally, the defects type 2B and type 3 are associated with several damaged metaphyseal bone and loss of cortical bone. Structural allografts have been used for the treatment of large, contained, or uncontained osseous defect in revision TKA. Disadvantages of using structural allografts include late resorption or nonunion and risk of disease transmission. Alone, the structural allograft can not provide the initial support for revision implants. In these cases the stems are frequently used to provide the necessary load sharing and increase initial component stability. When evaluating whether stems should be cemented or press-fit, there isn't a simple answer, since there are no clear advantages or disadvantages for each approach. The aim of this study was to evaluate load sharing and stability at bone graft-cement interface under femoral component with use of cemented and press-fit stems after allograft incorporation with host bone. The difficulties encountered or the impossibility on the evaluation of these biomechanical parameters in-vitro make the use of finite element (FE) models a way through this evaluation. The FE results suggest that a press-fit stem could be the adequate choice if structural allografts in femur revision are used.

The influence of different tibial stem designs in load sharing and stability at the cement-bone interface in revision TKA

Total Knee Arthroplasty (TKA) changes mechanical loading of the knee joint. Bone loss in the tibia is commonly encountered at the time of the revision TKA. Restoration of lost bone support and joint stability are the primary challenges in revision TKA. Normally, these defects are treated with non-living structures like metallic augments or bone grafts (autografts or allografts). Alone, neither of these structures can provide the initial support and stability for revision implants. In the latter, the use of intramedullary stems can provide the necessary load sharing and protect the remaining host bone and graft from excessive stress, increasing component stability. The purpose of this study was to evaluate comparatively load sharing (cortical rim, cancellous bone and stem) and stability at the cement-bone interface under the tibial tray induced by the use of cemented and press-fit tibial component stem extensions. Furthermore the study of the desirable option in cases where the bone defect is cavitary (cancellous bone defect contained by an intact cortical rim) or uncontained bone defect (bone loss involving the supporting cortical rim) was carried out. Because in vitro evaluation of these biomechanical parameters is difficult we used finite element (FE) models to overcome this. The biomechanical results suggest an identical behaviour in case of cavitary defects for both types of stems assessed. In the case of uncontained defect treated with bulk allografts the cemented stem may be a prudent clinical option.

Rapidly cooled horse spermatozoa: Loss of viability is due to osmotic imbalance during thawing, not intracellular ice formation

The cellular damage that spermatozoa encounter at rapid rates of cooling has often been attributed to the formation of intracellular ice. However, no direct evidence of intracellular ice has been presented. An alternative mechanism has been proposed by Morris (2006) that cell damage is a result of an osmotic imbalance encountered during thawing. This paper examines whether intracellular ice forms during rapid cooling or if an alternative mechanism is present. Horse spermatozoa were cooled at a range of cooling rates from 0.3 to 3,000 degrees C/min in the presence of a cryoprotectant. The ultrastructure of the samples was examined by Cryo Scanning Electron Microscopy (CryoSEM) and freeze substitution, to determine whether intracellular ice formed and to examine alternative mechanisms of cell injury during rapid cooling. No intracellular ice formation was detected at any cooling rate. Differential scanning Calorimetry (DSC) was employed to examine the amount of ice formed at different rate of cooling. It is concluded that cell damage to horse spermatozoa, at cooling rates of up to 3,000 degrees C/min, is not caused by intracellular ice formation. Spermatozoa that have been cooled at high rates are subjected to an osmotic shock when they are thawed.

Finite Element and Experimental Cortex Strains of the Intact and Implanted Tibia

Finite Element (FE) models for the simulation of intact and implanted bone find their main purpose in accurately reproducing the associated mechanical behavior. FE models can be used for preclinical testing of joint replacement implants, where some biomechanical aspects are difficult, if not possible, to simulate and investigate in vitro. To predict mechanical failure or damage, the models should accurately predict stresses and strains. Commercially available synthetic femur models have been extensively used to validate finite element models, but despite the vast literature available on the characteristics of synthetic tibia, numerical and experimental validation of the intact and implant assemblies of tibia are very limited or lacking. In the current study, four FE models of synthetic tibia, intact and reconstructed, were compared against experimental bone strain data, and an overall agreement within 10% between experimental and FE strains was obtained. Finite element and experimental (strain gauge) models of intact and implanted synthetic tibia were validated based on the comparison of cortex bone strains. The study also includes the analysis carried out on standard tibial components with cemented and noncemented stems of the P.F.C Sigma Modular Knee System. The overall agreement within 10% previously established was achieved, indicating that FE models could be successfully validated. The obtained results include a statistical analysis where the root-mean-square-error values were always <10%. FE models can successfully reproduce bone strains under most relevant acting loads upon the condylar surface of the tibia. Moreover, FE models, once properly validated, can be used for preclinical testing of tibial knee replacement, including misalignment of the implants in the proximal tibia after surgery, simulation of long-term failure according to the damage accumulation failure scenario, and other related biomechanical aspects.

Experimental validation of intact and implanted distal femur finite element models

Four finite element (FE) models of intact and distal femur of knee replacements were validated relative to measured bone strains. FE models of linear tetrahedrons were used. Femoral replacements with cemented stemless, cemented and noncemented femoral stems of the PFC Sigma Modular Knee System were analyzed. Bone strains were recorded at ten locations on the cortex. The magnitude of the FE bone strains corresponded to the mean measured strains, with an overall agreement of 10%. Linear regression between the FE and mean experimental strains produced slopes between 0.94 and 1.06 and R(2) values between 0.92 and 0.99. RSME values were less than 12%. The FE models were able to adequately replicate the mechanical behavior of distal femur reconstructions.

Stabilization of frozen Lactobacillus delbrueckii subsp. bulgaricus in glycerol suspensions: Freezing kinetics and storage temperature effects

The interactions between freezing kinetics and subsequent storage temperatures and their effects on the biological activity of lactic acid bacteria have not been examined in studies to date. This paper investigates the effects of three freezing protocols and two storage temperatures on the viability and acidification activity of Lactobacillus delbrueckii subsp. bulgaricus CFL1 in the presence of glycerol. Samples were examined at -196 degrees C and -20 degrees C by freeze fracture and freeze substitution electron microscopy. Differential scanning calorimetry was used to measure proportions of ice and glass transition temperatures for each freezing condition tested. Following storage at low temperatures (-196 degrees C and -80 degrees C), the viability and acidification activity of L. delbrueckii subsp. bulgaricus decreased after freezing and were strongly dependent on freezing kinetics. High cooling rates obtained by direct immersion in liquid nitrogen resulted in the minimum loss of acidification activity and viability. The amount of ice formed in the freeze-concentrated matrix was determined by the freezing protocol, but no intracellular ice was observed in cells suspended in glycerol at any cooling rate. For samples stored at -20 degrees C, the maximum loss of viability and acidification activity was observed with rapidly cooled cells. By scanning electron microscopy, these cells were not observed to contain intracellular ice, and they were observed to be plasmolyzed. It is suggested that the cell damage which occurs in rapidly cooled cells during storage at high subzero temperatures is caused by an osmotic imbalance during warming, not the formation of intracellular ice.

Simulation of Physiological Loading in Total Hip Replacements

The determination of biomechanical force systems of implanted femurs to obtain adequate strain measurements has been neglected in many published studies. Due to geometric alterations induced by surgery and those inherent to the design of the prosthesis, the loading system changes because the lever arms are modified. This paper discusses the determination of adequate loading of the implanted femur based on the intact femur-loading configuration. Four reconstructions with Lubinus SPII, Charnley Roundback, Müller Straight and Stanmore prostheses were used in the study. Pseudophysiologic and nonphysiologic implanted system forces were generated and assessed with finite element analysis. Using an equilibrium system of forces composed by the Fx (medially direction) component of the hip contact force and the bending moments Mx (median plane) and My (coronal plane) allowed adequate, pseudo-physiological loading of the implanted femur. We suggest that at least the bending moment at the coronal plane must be restored in the implanted femur-loading configuration.

Rupestris stem pitting associated virus isolates are composed by mixtures of genomic variants which share a highly conserved coat protein

Broad spectrum primers were used to amplify a fragment comprising the CP gene and putative ORF6 by RT-PCR from ds-RNA templates originating from 46 Portuguese varieties, totalling 190 samples, including some wild Vitis ssp sylvestris vines, and 2 vines from Slovenia. SSCP analysis was used as a preliminary screen to avoid cloning and sequencing very similar variants. Four groups of variants were recognized. In pair wise comparisons between nucleotide sequences the minimal homology found was 81%. In case of the cultivated varieties, no relationship could be seen between the phylogenetic groups and geographic origin or grape variety. Several isolates were found harbouring mixed infections with genomic variants from different groups, but the mixing did not lead to an extensive recombination between them. The deduced amino-acid sequences revealed a conserved CP subjected to strong purifying selection pressure. Analysis of the selection pressure operating on the putative ORF6 suggests that this ORF does not exist. Previously produced polyclonal antiserum raised against the recombinant CP of RSPaV expressed in Escherichia coli was shown to be able to detect all four groups of variants of RSPaV included in this study, which might enable the diagnosis of the virus on a serological basis.

Genomic variability of prune dwarf virus as affected by agricultural practice

Twelve new sequences of the coat protein gene of Prune dwarf virus (PDV) variants, obtained from almond trees, are presented. Comparison with previously reported sequences of the same region, obtained from other hosts (plum, cherry and peach) revealed not only the existence of a wider range of variants of PDV than formerly predicted, but also the frequent presence of a mixture of variants in each sample. In spite of the heterogeneity found in almond, the amino acid composition of the domain at the N terminus of the coat protein maintained the potential to form an amphipathic helix, and hence the capacity to serve the previously suggested function of binding the viral RNA during particle formation. Except for synonymous substitutions, measures of nucleotide diversity calculated for the two groups, respectively 13 sequences from almond and 14 sequences from other hosts, were found to be significantly different, with the almond group showing a much higher variability. Analysis of the dendrogram constructed based in all 27 PDV CP sequences did not reveal host specificity, in agreement with previous findings. However, a clear divergence between almond and other hosts sequences could be found. It is discussed that the observed differences between almond and other hosts variants may derive from differences in agricultural practices.

Operating conditions that affect the resistance of lactic acid bacteria to freezing and frozen storage

Thermophilic lactic acid bacteria exhibit different survival rates during freezing and frozen storage, depending on the processing conditions. We used a Plackett and Burman experimental design to study the effects of 13 experimental factors, at two levels, on the resistance of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus to freezing and frozen storage. The resistance was evaluated by quantifying the decrease of acidification activity during freezing and throughout 8 weeks of storage. Acidification activity after freezing and frozen storage was affected by 12 experimental factors. Only the thawing temperature did not show any significant effect. S. thermophilus was more resistant than L. bulgaricus and the cryoprotective effect of glycerol during freezing and storage was confirmed. The temperature and duration of the cryoprotection step influenced acidification activity following the freezing step: the lower the temperature and the shorter the duration, the higher the activity. Acidification activity after storage was affected by several experimental factors involved in the fermentation stage: use of NaOH instead of NH4OH for pH control, addition of Tween 80 in the culture medium, and faster cooling led to better cryotolerance. Resistance to freezing and frozen storage was improved by using a high freezing rate and a low storage temperature. Finally, this study revealed that the conditions under which lactic acid bacteria are prepared should be well controlled to improve their preservation and to limit the variability between batches and between species.

Resistance to freezing and frozen storage of Streptococcus thermophilus is related to membrane fatty acid composition

The resistance to freezing and frozen storage of Streptococcus thermophilus was related to the fatty acid composition of the cell membrane. The effects of four experimental factors were investigated on the fatty acid concentrations and on the recovery of acidification activity of S. thermophilus stored at -20 degrees C by using a complete experimental design: incorporating oleic acid in the culture medium, fermentation pH, addition of glycerol as cryoprotective agent and duration of storage. The acidification activity decreased during the freezing and the frozen storage of S. thermophilus. The storage time slightly enhanced the unsaturated fatty acid concentrations. The addition of glycerol did not modify the fatty acid composition but increased the resistance to frozen storage. The addition of oleic acid and the decrease of the fermentation pH enhanced the ratio unsaturated:saturated fatty acids and improved the recovery of the acidification activity. These results indicate that the resistance to frozen storage was closely related to the membrane fatty acid composition. We interpreted this as an adaptation of S. thermophilus to the addition of oleic acid and the unfavorable growth conditions that corresponded to a low fermentation pH.

Pyoderma gangrenosum associated with sclerosing cholangitis, type 1 diabetes mellitus and ulcerative colitis

We describe the case of a 22-year-old black female with type 1 diabetes mellitus diagnosed when she was 12 years old. She first presented (March 1994) with pustules and ulcerations on the upper and lower limbs, trunk and scalp at the age 17. The diagnosis of pyoderma gangrenosum was made. Since presentation, changes in liver function were detected and subsequent study led to the diagnosis of sclerosing cholangitis. The diagnosis of ulcerative colitis was made after colonoscopy. Partial response was obtained with minocycline and clofazimine, but treatment with 5-aminosalicylic acid achieved no improvement of the ulcerations. Liver transplantation, followed by immunosuppressive therapy led to complete regression of the cutaneous lesions.

Method of quantifying the loss of acidification activity of lactic acid starters during freezing and frozen storage

We have developed a method to quantify the resistance to freezing and frozen storage of lactic acid starters, based on measuring the time necessary to reach the maximum acidification rate in milk (tm) using the Cinac system. Depending on the operating conditions, tm increased during the freezing step and storage. The loss of acidification activity during freezing was quantified by the difference (delta tm) between the tm values of the concentrated cell suspension before and after freezing. During storage at -20 degrees C, linear relationships between tm and the storage time were established. Their slope, k, allowed the quantitation of the decrease in acidification activity during 9-14 weeks of frozen storage. The method was applied to determine the resistance to freezing and frozen storage of four strains of lactic acid bacteria and to quantify the cryoprotective effect of glycerol.

Tumor necrosis factor during pregnancy and at the onset of labor and spontaneous abortion

OBJECTIVE

The aim of this study was to evaluate the production of tumor necrosis factor (TNF) by peripheral blood cells during pregnancy, at the onset of labor and of spontaneous abortion (SA), as well as in non-pregnant women with and without a history of recurrent spontaneous abortions (RSA).

STUDY DESIGN

The peripheral blood cells TNF production was evaluated in 28 women in the 1st trimester of pregnancy, 21 in the 2nd, and 30 in the 3rd, 47 at term labor; 43, at the onset of SA; 19 healthy and 19 RSA non-pregnant women. The statistical method used was the Mann-Whitney test.

RESULTS

We observed (1) lack of TNF detection in the 1st gestational trimester; (2) increase of TNF production with gestational age, with the highest values being observed at labor (P<0.05); (3) high TNF production at the onset of SA; (4) no difference in the TNF production by healthy and RSA non-pregnant women.

CONCLUSIONS

The suppression of TNF production during the 1st trimester of pregnancy seems to favor the normal development of pregnancy. It remains to be investigated whether the assessment of TNF production is a valuable prognostic parameter for the occurrence of abortion.

Ultrastructure of Helicobacter trogontum in culture and in the gastrointestinal tract of gnotobiotic mice

Helicobacter trogontum is a micro-aerophilic urease-positive bacterium that has recently been isolated from the intestinal mucosa of rats. The purpose of this investigation was to study the ultrastructural details of this micro-organism in both pure culture and in the gastrointestinal tract of germ-free mice infected with H. trogontum. The micro-organism was a fusiform to slightly spiral gram-negative cell, 4-6 microm long and 0.6-0.7 microm wide, with four to seven bipolar sheathed flagella. The cytoplasm presented several irregular and also globular granules. On each side of the polar regions of the cells, there was a highly electron-dense band, the 'polar membrane'. Coccoidal forms were seen in old cultures. H. trogontum showed several ultrastructural characteristics of the Helicobacter genus and much resemblance to H. rappini and H. bilis. H. trogontum mainly colonised the large bowel of the gnotobiotic mice where it could be seen in the lumen and also inside the enterocytes. Vacuolation of the ileal epithelial cells, loss of microvilli and pronounced desquamation of the enterocytes of the caecum were observed in the bowel colonised by the bacterium. These observations raise the possibility that H. trogontum could cause some harm to the host at least in particular circumstances such as when it colonises the gastrointestinal tract of a germ-free host.

Inhibitory serum factor of lymphoproliferative response to allogeneic cells in pregnancy

INTRODUCTION

An inhibitory serum factor of mixed lymphocyte culture (MLC) has been associated with successful pregnancy after lymphocyte transfusion in women with unexplained recurrent spontaneous abortions (RSA).

OBJECTIVE

Investigate whether the inhibitory serum factor of MLC is essential for a successful pregnancy.

METHOD

Sera from 33 healthy pregnant women and from 40 women with RSA were assessed by a one-way MLC in which the woman's lymphocytes were stimulated with her partner's lymphocytes or with third party lymphocytes.

RESULTS

An inhibitory serum effect (inhibition > 50% as compared to normal serum) was detected in 45% of the pregnant women who had at least 1 previous parity, in 8% of the primigravidea, in 29% of those with one abortion and in 58% of those with more than one abortion.

CONCLUSION

MLC inhibitory serum factor does not seem to be an essential factor for pregnancy development. Therefore, it should not be considered as a parameter for the assessment of RSA patients.

[TSH anti-receptor antibodies in Graves' disease]

The purpose of this study was to evaluate the sensitivity, specificity and predictive value of thyrotropin receptor antibody (TRAb) in the diagnosis of Graves disease. TRAb was tested by an isotopic receptor assay-TRAK Henning-in 80 newly diagnosed, untreated Graves disease patients (group I), 63 with other thyroid diseases (group II) and 60 controls (group III). In group I, 11 patients were TRAb negative and 7 were considered in the gray area (TRAb between 9 and 14 U/L). In group II, only 2 patients had TRAb 9 U/l and all controls were TRAb negative. For statistical analysis patients with TRAb in gray area were excluded. Sensitivity and specificity for this assay were 84.5 and 100% respectively. Predictive value of 100% affords certainty that a hyperthyroid patient with a positive TRAb has Graves disease, not sequining a scintigram.

[Myxedema coma]

Five patients, 4 female and 1 male, aged 45 to 73, were observed in myxedema coma between 1984 and 1992. In three patients hypothyroidism was not known. Depressed consciousness, hypothermia, bradycardia and no goiter were common to all and a precipitating factor could be identified in 3 of them. Therapy included L-thyroxine and/or triiodothyronine by nasogastric tube, hydrocortisone and supportive measures. Outcome was good in the 2 patients with known precipitating event, less impaired consciousness and normalization of body temperature by the third day of treatment.

Photosynthetic capacity of leaves of Eucalyptus globulus (Labill.) growing in the field with different nutrient and water supplies

The effects of water and nutrient availability on photosynthetic capacity of juvenile and adult leaves of Eucalyptus globulus Labill. seedlings were evaluated by measuring oxygen evolution at light and CO(2) saturation. Seedlings supplied with near optimal amounts of water and nutrients had higher growth rates than non-irrigated, unfertilized control seedlings, but photosynthetic capacity was similar in both treatments. Differences in foliar nitrogen concentrations between the two treatments were minor, which largely explains why the growth response to near optimal nutrition was not associated with an increase in photosynthetic capacity per unit leaf area. Nevertheless, the photosynthetic capacity of juvenile leaves decreased from distal to proximal positions in the mid-crown and was positively correlated with leaf nitrogen concentration expressed on a leaf surface area basis. During the dry season, non-irrigated, unfertilized seedlings fixed carbon at lower rates than irrigated seedlings supplied with near optimal nutrition because of stomatal closure even though photosynthetic capacity was unaffected by water deficits. In both treatments, there were differences between the photosynthetic capacity of adult and juvenile leaves that were largely explained by the low specific leaf area of adult leaves.

[Hyperthyroidism caused by non-neoplastic inappropriate TSH secretion]

We report a case of hyperthyroidism due to non-neoplastic inappropriate thyrotrophin secretion in a 31 year old woman. Increased T3 and THS levels after thyroidectomy led us to suspect the diagnose. Serum levels were further increased by TRH and only partially suppressed by triiodothyronine and computerised axial tomography showed a normal sellar region. These features are characteristic of inappropriate TSH secretion due to thyrotroph resistance to thyroid hormones. Bromocriptine and octreotide were ineffective in lowering TSH levels. Pregnancy and breastfeeding postponed 3,5,3'-triiodothyroacetic acid therapy.

[Myopathy caused by hypothyroidism]

The authors report a case of primary hypothyroidism where the main symptoms were caused by muscular lesions and disappeared after treatment with L-thyroxine. Based on this case study the authors then review both the clinical aspects and the diagnostical methods of hypothyroidism myopathy, noting its frequency, be it in terms of isolated laboratory changes or in terms of functional changes.

Arterial blood gas composition, consciousness and death in rabbits

Conscious rabbits were exposed to environments with low oxygen and/or high carbon dioxide. The electroencephalogram and arterial blood pressure were recorded. Arterial blood samples were taken sequentially. Rabbits became 'unconscious' at an arterial blood PO2 of 25 +/- 1 mm Hg and PCO2 of 99 +/- 27 mm Hg, when simultaneously the environmental oxygen was decreased and carbon dioxide increased. Brain death occurred at a PO2 of 23 +/- 1 mm Hg and PCO2 of 113 +/- 32 mm Hg. Cerebral perfusion was still adequate. In rabbits, the margin between 'unconsciousness' and 'death' is narrow so far as PO2 is concerned. If these results apply generally, animals culled with muscle relaxants may perceive stress involved until shortly before death.