Analysing the variations of shapes based on surface-models.

In this paper we present a freely available application with which surface models, e.g. triangle meshes can be registered rigidly as well as by using similarity or affine transformations. Registered surfaces can be analysed, i.e. their difference can be calculated and visualised in various ways. The software is addressing the problem of evaluating shape differences of generated surface models due to mesh relaxation, decimation, object (in our case: patient) variation, different co-ordinate systems, etc. We invite all interested research personnel to download and use the software.

In vitro activity of levofloxacin against contemporary clinical isolates of Legionella pneumophila, Mycoplasma pneumoniae and Chlamydia pneumoniae from North America and Europe.

OBJECTIVE: To assess the activities of levofloxacin and the comparator agents erythromycin, clarithromycin, azithromycin and doxycycline against atypical respiratory pathogens. METHODS: One hundred and forty-six Legionella pneumophila, 41 Mycoplasma pneumoniae and nine Chlamydia pneumoniae isolates were procured from various culture collections in North America and Europe and tested for susceptibility to the above agents by broth microdilution. The isolates came primarily from clinical sources and were collected from patients between 1995 and 1999. RESULTS: Against L. pneumophila, levofloxacin was the most active agent, with an MIC(90) of 0.03 mg/L, twofold more active than clarithromycin (0.06 mg/L), 16-fold more active than erythromycin and azithromycin (0.5 mg/L) and 64-fold more active than doxycycline. Against M. pneumoniae, azithromycin (MIC(90) < or = 0.0005 mg/L) was the most active agent. However, two isolates of M. pneumoniae, one from the USA and one from Finland, were macrolide resistant (MIC > or = 4 mg/L), but levofloxacin susceptible (MIC 0.25 mg/L). The geographic origin of L. pneumophila and M. pneumoniae did not affect the MIC range for any antimicrobial agent tested. Against C. pneumoniae, clarithromycin was the most active agent, with an MIC range of < or =0.008-0.03 mg/L. CONCLUSIONS: Levofloxacin had comparable activity to the other agents tested against the atypical respiratory pathogens, confirming its potential as an alternative for empirical therapy of community-acquired pneumonia.

Temporal aspects related to the perception of skatole and androstenone, the major boar odour compounds.

Pork fat samples from 50 boars slaughtered at a commercial abattoir were analysed for skatole and androstenone concentrations and grouped within a 3×3 matrix representing low, medium and high levels of the odour compounds. A 10 member sensory panel, screened and trained to recognise and quantify skatole and androstenone odour intensities, was used to verify the human perception of boar odour in these pork fat samples immediately after heating (±65°C) and following a cooling period of ten minutes (±25°C). Principal component analysis revealed that the sensory panel differentiated the pork fat samples first and foremost on the basis of the presence or absence of androstenone and/or skatole odours and secondly on the character of the androstenone or skatole odour. Evidence of adaptation towards the odour of skatole was shown by a decreased sensitivity over replicates. Sensory perception of boar odour seems to have a temporal character which can be explained by differences in volatilisation (involving both odourant release and retention) of skatole and androstenone, odour synergism and possibly differences in the properties of the fat matrix of different samples. The results suggest that factors influencing volatilisation of skatole and androstenone should also be considered when predicting sensory responses of boar odour.

Reaction to boar odour by different South African consumer groups.

A consumer sensory study of South African pork consumers (n=300) including equal numbers of males and females and consumers from three ethnic groupings (black, white and coloured consumers) was conducted to determine the effects of gender and ethnicity on consumer reactions towards boar odour compounds. Samples consisted of boar fat with varying concentrations of skatole and androstenone. Each consumer evaluated the odour of seven fat samples. Consumers' liking of pork meat in general had a significant effect on the hedonic rating of the boar odour. The majority of consumers represented in this study would be dissatisfied with pork meat exhibiting detectable levels of skatole. In general, more females compared with males, will also respond more negatively towards samples with detectable levels of androstenone. An apparent liking for samples with medium levels of androstenone (0.5-1 µg/g) was found for some consumers, especially males, and can be partly attributed to the inability of some consumers to smell this compound at these levels or a genuine liking for the odour of androstenone. Significant differences in the sensitivity of consumers from different ethnic groups were found with white females responding more negatively than white males and blacks. Although it was not possible to compare responses directly with the white and black groups, it was found that a higher percentage of coloureds responded negatively to boar odour compounds. Coloured males responded particularly negatively towards samples with detectable skatole, while black males, in general, were found to be more critical than black females. Based on these results it is predicted that the majority of consumers would be less willing to consume pork meat exhibiting detectable levels of boar odour.

Benchmarking the in vitro activities of moxifloxacin and comparator agents against recent respiratory isolates from 377 medical centers throughout the United States.

To benchmark the activity of moxifloxacin (a newer fluoroquinolone), a U.S. study comprising 16,141 contemporary isolates of Streptococcus pneumoniae (5,640), Haemophilus influenzae (6,583), and Moraxella catarrhalis (3,648) referred from 377 institutions during 1998 is described. For S. pneumoniae the modal MIC and MIC at which 90% of the isolates were inhibited (MIC(90)) for moxifloxacin were 0.12 and 0.25 microg/ml, respectively, independent of susceptibility to other drug classes, geography, or site of infection. Eleven isolates were intermediate or resistant to levofloxacin and grepafloxacin; of these isolates, 1 remained susceptible to sparfloxacin, 2 remained susceptible to moxifloxacin, and 4 remained susceptible to trovafloxacin. All 11 isolates possessed classic mutations in gyrA and/or parC known to confer reduced susceptibility to fluoroquinolones. Four isolates (originating from four separate states) belonging to a multidrug-resistant, fluoroquinolone-resistant clone were identified by pulsed-field gel electrophoresis. For moxifloxacin and trovafloxacin, at least 87% of isolates demonstrated MICs > or =3 twofold concentrations below the susceptibility breakpoints, in contrast to no more than 15% for levofloxacin, grepafloxacin, and sparfloxacin. Of the isolates that were multidrug resistant (7.4%), >98% remained susceptible to moxifloxacin. The modal MIC and MIC(90) for M. catarrhalis (both 0.06 microg/ml) and for H. influenzae (both 0.03 microg/ml) were independent of beta-lactamase production. These data demonstrate the in vitro activity of moxifloxacin and establish a baseline for future studies.

Benchmarking the in vitro activity of moxifloxacin against recent isolates of Streptococcus pneumoniae, Moraxella catarrhalis, and Haemophilus influenzae. A European multi-centre study.

To benchmark the activity of moxifloxacin, a European study comprising 900 Streptococcus pneumoniae, 1051 Haemophilus influenzae, and 226 Moraxella catarrhalis referred from 30 institutions during 1998 is described. For S. pneumoniae, moxifloxacin and trovafloxacin MIC(90) and modal MICs values were 0.12 microg/ml and independent of susceptibility to other drug classes, geography, or site of infection. MIC(90)/modal MICs were, respectively, 0.25/0.12 microg/ml for grepafloxacin, 0.25/0.25 microg/ml for sparfloxacin, and 1.0/0.5 microg/ml for levofloxacin. The moxifloxacin C(max):MIC ratio of 20.8-26.3 is higher than comparator fluoroquinolones. Five isolates were intermediate or resistant to grepafloxacin, sparfloxacin, or levofloxacin of which four and three remained susceptible to trovafloxacin and moxifloxacin, respectively. For moxifloxacin, > 90% of S. pneumoniae isolates demonstrated MICs > or =3 dilutions below the susceptibility breakpoint used. Modal MICs and MIC(90) for M. catarrhalis (both 0.03 microg/ml) and H. influenzae (0.03 microg/ml and 0.06 microg/ml) were independent of beta-lactamase production. These data demonstrate the in vitro activity of moxifloxacin and establish a baseline for future surveillance studies that will be important for detecting and tracking any trends in changing activity of this fluoroquinolone.

Two groups of bacteriophages infecting Streptococcus thermophilus can be distinguished on the basis of mode of packaging and genetic determinants for major structural proteins.

A comparative study of 30 phages of Streptococcus thermophilus was performed based on DNA restriction profiles, DNA homology, structural proteins, packaging mechanisms, and host range data. All phages exhibited distinct DNA restriction profiles, with some phages displaying similarly sized restriction fragments. DNA homology was shown to be present among all 30 phages. The phages could be divided into two groups on the basis of their packaging mechanism as was derived from the appearance of submolar DNA fragments in restriction enzyme digests and the presence (cos-containing phages) or absence (pac-containing phages) of cohesive genomic extremities. Interestingly, the 19 identified cos-containing phages possessed two major structural proteins (32 and 26 kDa) in contrast to the remaining 11 pac-containing phages, which possessed three major structural proteins (41, 25, and 13 kDa). Southern hybridization demonstrated that all pac-containing phages tested contain homologs of the genes encoding the three major structural proteins of the pac-containing phage O1205, whereas all cos-containing phages tested exhibit homology to the gene specifying one of the structural components of the cos-containing phage phi 7201. Fifty-seven percent of the phages (both cos and pac containing) possessed the previously identified 2.2-kb EcoRI fragment of the temperate S. thermophilus phage Sfi18 (H. Brüssow, A. Probst, M. Frémont, and J. Sidoti, Virology 200:854-857, 1994). No obvious correlation was detected between grouping based on packaging mechanism and host range data obtained with 39 industrial S. thermophilus strains.

A comparison of some muscle metabolites in stress susceptible and resistant Landrace gilts after halothane exposure or exercise stress.

Sixty-six South African Landrace gilts were used in the experiments. At the age of 21 weeks, 47 of the pigs were challenged with halothane exposure. As a result 17 of the pigs died, and were classified stress susceptible (SS), whereas the 30 survivors were classified stress resistant (SR). The other 19 pigs were subjected to treadmill exercise. Four of the exercised pigs died. The pigs that survived the treadmill exercise were later exposed to halothane. The pigs that died as a result of the halothane exposure (n = 5) or the treadmill exercise (n = 4), were classified SS (n = 9) and the survivors as SR (n = 10). A biopsy of the M. semitendinosus was used for measurement of difference in muscle lactate, ATP, glucose 6-phosphate, phosphocreatine, glucose and glycogen concentrations. The results show that in all pigs exercise resulted in the higher stimulation of glycogenolysis than did halothane exposure. However, SS pigs overall showed a greater stimulation of glycogenolysis and glycolysis and general anaerobic metabolism, compared to SR pigs. Under halothane exposure, glycogenolysis and anaerobic metabolism were stimulated in the SS pigs to a much greater extent than in SR pigs, with significant differences between all the muscle metabolites determined. However, treadmill exercise, although sufficient to cause death in some pigs, resulted only in significantly higher lactate and glucose 6-phosphate concentrations. SR pigs exposed to halothane had significantly higher ATP, phosphocreatine and glycogen concentrations, but a lower glucose concentration than exercised SR pigs, indicating less severe stimulation of glycogenolysis by halothane than exercise. No significant differences were found in the determined muscle metabolites in SS pigs exposed to halothane compared to exercised SS pigs. In conclusion, these differences suggest that different mechanisms of stimulation of metabolism on exposure to halothane and exercise may exist, although both types of stress cause stimulation of glycogenolysis.

[Collagen in boerewors as a measure of quality]. / Kollageen in boerewors as maatstaf van gehalte.

Formalin-fixed samples (n = 75) of commercial boerewors (traditional farm style sausage) were examined for total nitrogen (N) and hydroxyproline (Hypro) N to assess their collagen content. Hypo N/total N x 10(3) (unaffected by residual fat) varied from 8.23 to 16.50; 3/75 (5%) of samples had ratios equal to or less than the control (8.38) i.e. sausage home-made from meat without addition of scraps or collagen-rich trimmings. About 95% of samples had ratios greater than 10, and 5% had ratios greater than double the control. In 75% of the surveyed samples, the ratios were more than 1.5 times greater than those of the control. To ensure boerewors of good compositional quality, it is advocated that formalin-fixed samples of the product be subjected to both histological examination and collagen determinations. Promulgation of legislation to limit the collagen content of boerewors is proposed; a maximum of 12 in the ratio of Hypro N/total N x 10(3) is considered reasonable and attainable in the light of the results of this survey.

Stress resistant and stress susceptible landrace pigs: comparison of blood variables after exposure to halothane or exercise on a treadmill.

Stress susceptible pigs develop pale, soft, exudative pork as a consequence of exposure to natural stress or exposure to halothane. Hyperstimulation of glycolysis is a major component of the stress reaction. Whether natural and artificial stress have other similarities was investigated by exposing pigs to halothane or to physical exercise, and measuring their blood composition. There were many similarities between the two groups but the significant differences suggest that although both halothane and exercise induce glycolysis, the mechanisms involved are different.

A rapid (4--6-hour) urine-culture system for direct identification and direct antimicrobial susceptibility testing.

This study evaluates a new direct rapid system for urine cultures, including detection and quantitation of positive specimens by Gram stain, direct identification by 4--6-hour incubation of sediment with reagent strips, and antibiotic susceptibility testing by direct (3--4-hour) disk-elution methods. Of 987 routine urine specimens, 121 had significant (less than or equal to 10(5) colony-forming units/ml) gram-negative bacilluria, of which 89% were detected by the Gram stain. Direct rapid identification was correct in 94%. Results of direct disk-elution antimicrobial tests showed overall agreement with results of standard disk diffusion of 93% of tests, and major discrepancies in 4%. For urine specimens with gram-negative bacilluria, this system permitted detection, quantitation, identification, and antimicrobial susceptibility testing in four to six hours with reasonable, though not complete, accuracy.