Biomedical subjects
Publications and source records attributed to P Janssen.
To assess how automatic function assignment will contribute to genome annotation in the next five years, we have performed an analysis of 31 available genome sequences. An emerging pattern is that function can be predicted for almost two-thirds of the 73,500 genes that were analyzed. Despite progress in computational biology, there will always be a great need for large-scale experimental determination of protein function.
This article describes a program developed to improve the process of planned induction of labour and to reduce the rates of inappropriate induction. The setting is a tertiary-care maternity hospital in urban Vancouver, BC, in which 7000 deliveries take place annually. Approximately 65% of these can be considered primary care; the remainder are secondary- or tertiary-level cases. Continuous quality improvement (CQI) methods were used by a multidisciplinary team, which included nursing staff, physicians, health records personnel and a CQI facilitator. Interventions included the development of a new induction-booking process, clear criteria for induction, feedback to caregivers about changes and a peer review system to oversee and maintain improvement. The overall induction rate for the institution decreased, and this change has been maintained.
The anterior part of the macaque inferior temporal cortex, area TE, occupies a large portion of the temporal lobe and is critical for object recognition. Thus far, no relation between anatomical subdivisions of TE and neuronal selectivity has been described. Here, we present evidence that neurons selective for three-dimensional (3D) shape are concentrated in the lower bank of the superior temporal sulcus, whereas neurons in lateral TE are generally unselective for 3D shape, though equally selective for 2D shape. These findings reveal that TE consists of at least two distinct areas, one of which processes a specific object property.
Neurons in the rostral lower bank of the superior temporal sulcus (TEs), part of the inferior temporal cortex, respond selectively to three-dimensional (3D) shapes. We have investigated how these neurons represent disparity-defined 3D structure. Most neurons were selective for either first-order (disparity gradients) or second-order (disparity curvature) disparities. The latter selectivity proved remarkably vulnerable to disparity discontinuities, such as sharp edges or steps in disparity. The majority of the neurons remained selective for small disparity variations within the stimulus. 3D shape selectivity was preserved when the frontoparallel position or the stimulus size was altered. Thus, in TEs, 3D shape is coded by first- and second-order disparity-selective neurons, which are highly sensitive to spatial variations of disparity.
We present a case of acute-onset diabetes insipidus in a 60-year-old woman who had been treated for breast cancer. MR images showed a thickened and enhancing pituitary stalk and an asymmetrical hypophysis. The clinical diagnosis of a pituitary metastasis of the breast carcinoma was made.
The human endothelin B receptor (ET(B) receptor) was produced in the methylotrophic yeast Pichia pastoris under transcriptional control of the highly inducible alcohol oxidase 1 (AOX1) gene promoter. In the expression plasmids pPIC9KFlagET(B)Bio and pPIC9KFlag deltaGPET(B)Bio the ET(B) receptor coding region was fused in frame to the Saccharomyces cerevisiae alpha-factor prepropeptide and the FLAG-tag. In both constructs, the receptor was also fused to a biotinylation domain. Additionally, in pPIC9KFlag deltaGPET(B)Bio the putative N-glycosylation site and a protease site have been deleted by site directed mutagenesis. Crude membranes prepared from recombinant P. pastoris revealed specific and saturable binding of [125I]ET-1 with a K(D) of about 42 pM. Receptor levels of 60 pmol/mg and 35 pmol/mg for the Flag deltaGPET(B)Bio and the FlagET(B)Bio construct, respectively, were determined. The pharmacological profile for ET-1, ET-2 and ET-3 were as expected for a subtype B endothelin (ET) receptor. Immunoblot analysis showed an apparent molecular mass of 55 kDa for the Kex2-processed and about 74 kDa for the Kex2-unprocessed receptor. Contrary to the Flag deltaGPET(B)Bio construct, the FlagET(B)Bio construct was not correctly processed by the internal Kex2 endopeptidase. As was detected by ultrastructural analysis of recombinant yeast cells, high-level production of the receptor resulted in the formation of stacked membranes.
Real-world objects are three-dimensional (3D). Yet, it is unknown whether the neurons of the inferior temporal cortex, which is critical for object recognition, are selective for the 3D shape of objects. We tested for such selectivity by comparing responses to stereo-defined curved 3D shapes derived from identical pairs of monocular images. More than one-third of macaque inferior temporal neurons were selective for 3D shape. In the vast majority of those neurons, this selectivity depended on the global binocular disparity gradient and not on the local disparity. Thus, inferior temporal cortex processes not only two-dimensional but also 3D shape information.
PURPOSE: The invasive nature of vaginal sonography, recently introduced as an improved diagnostic method for imaging the contents of the pregnant uterus, has provoked discussion about patient preference for female sonographers. This study examined whether patients had a gender preference for the sonographer who would conduct such an examination. METHODS: Over 3 months, a written survey was given to pregnant women to complete anonymously while waiting for their scheduled sonographic examination. The survey covered gender preference for the sonographer and education, ethnicity, and previous experience with the procedure. Surveys were turned in by 1,002 pregnant women. RESULTS: Of the women whose survey responses were analyzed, 62% preferred a female sonographer. The principal reason given for this preference was comfort with the same gender. The majority of respondents were 25-40 years old, married, white, and multiparous. The level of education varied widely. CONCLUSIONS: These findings point to a need to seek consumer input when new technology is introduced, to provide women with choices where possible, and to ensure that they have access to information about those choices.
Forty-eight pneumococci were genotyped by on-line laser fluorescence amplified-fragment length polymorphism (AFLP) and pulsed-field gel electrophoresis (PFGE) analysis of chromosomal restriction fragments. Overall, the data generated by the two methods corresponded well. However, with AFLP, clusters were delineated at a higher similarity level, and isolate differentiation was more pronounced. AFLP and PFGE were equally efficient for assessing intraserotype diversity. We conclude that AFLP is a useful alternative to PFGE.
OBJECTIVE: To describe women's experiences with expectant management of spontaneous abortions. DESIGN: Descriptive survey using questionnaires with fixed-choice and open-ended questions. The latter were analyzed for themes, using qualitative methods. SETTING: Urban and suburban private primary care family practices. PARTICIPANTS: A convenience sample of family practice patients (59 of 80 eligible) pregnant for less than 12 weeks who had spontaneous abortions without surgery. Response rate was 84.7%; 50 questionnaires were received from the 59 women. METHOD: Women were asked about their physical experiences, including amount of pain and bleeding; emotional effects; their satisfaction with medical care; and their suggestions for improving care. MAIN FINDINGS: The mean worst pain experienced during a spontaneous abortion on an 11-point scale was 5.9. Bleeding varied, but was often very heavy. Satisfaction rate was 92.9% with family physician care and 84.6% with hospital care. Women described the emotional effect of "natural" spontaneous abortions and made recommendations for improving care. CONCLUSIONS: A better understanding of the physical and emotional experiences of the women in this study might help physicians better prepare and support patients coping with expectant management of spontaneous abortions.
OBJECTIVE: To test the effectiveness of physician and patient education in reducing the rate of surgery in management of spontaneous abortions in family practice. DESIGN: A before-after intervention trial. SETTING: Urban and suburban family doctors' practices in greater Vancouver, BC. PARTICIPANTS: Family practice patients (56 physicians contributed 417 patients) who had spontaneous abortions between June 1997 and August 1998. INTERVENTIONS: Seminars for doctors and educational pamphlets for patients. MAIN OUTCOME MEASURES: Rate of surgeries, and rates of referrals and complications. RESULTS: In the 2 years before the intervention, the rate of surgery was 45.8% (n = 299); after, it was 32.2% (n = 118). No transfusions were required. Before the intervention, 17% of women had hemorrhages; after, 13%. Rates of infection were 3.7% and 0.8%, respectively. Rates of referral to gynecologists were 54.0% and 40.2%, respectively. CONCLUSIONS: Patients of family doctors who attended seminars and agreed to join the study had significantly reduced rates of surgery after spontaneous abortions. Rates of referral for these patients were also lower, and there was no increase in complications.
Commercial citrus pectin containing galacturonic acid and rhamnose in a ratio of approximately 40:1 was saponified and then exhaustively digested with endopolygalacturonase (EPG). The products were separated by ultrafiltration into low-molecular-weight (LMW) and high-molecular-weight (HMW) fractions. The LMW fraction accounted for 80% of the starting material, but for only 10% of the total rhamnose. The molar ratio of galacturonic acid to rhamnose of the LMW fraction was 236, suggesting that very few small Rha-containing oligomers were generated by the EPG digestion. No distinct Rha-containing oligomers were found by various chromatographic analyses of the LMW fraction. The HMW fraction, which only accounted for 10% by weight of the starting pectin, contained more than 85% of the rhamnose. The ratio of GalA to Rha in the HMW fraction was 1.7:1 and partial acid hydrolysis of this fraction produced a series of oligomers consisting of GalA-Rha repeating units, suggesting that it contained rhamnogalacturonan, which has a backbone composed of GalA-Rha disaccharide repeating units. The HMW fraction also contained large amounts of arabinose and galactose, which probably originated from side chains linked to some of the rhamnose residues. We propose that commercial citrus pectin is composed of two regions: the predominant region consists of chains of uninterrupted 1,4-linked alpha-D-GalA residues with between 60-70% of the residues methyl esterified; and the other region consists of rhamnogalacturonan with a backbone composed of GalA-Rha disaccharide repeating units and neutral sugar side chains.
AFLP is a novel high-resolution PCR-based DNA fingerprinting method generating complex banding patterns that can be used for comparative analysis. In the present study, the applicability of AFLP in fingerprinting Staphylococcus epidermidis isolates was investigated. The criteria considered were stability of patterns, reproducibility, discriminatory capacity and consistency with epidemiological context. Repeated testing of strains and investigation of subcultures showed that AFLP patterns were reproducible and stable with an intrastrain similarity of S > or = 94% as determined by analysis of digitized patterns. Fifteen unrelated strains were heterogeneous, with a level ranging from 78-93%. The applicability of AFLP in epidemiological studies of S. epidermidis was tested on 11 sets of four blood isolates each, from 11 patients with suspected septicaemia. Nine sets had indistinguishable or highly similar AFLP patterns for each isolate per set, while two sets had heterogeneous patterns. These results show that AFLP has high discriminatory power for strain identification in S. epidermidis.
The aim of this study was to determine if mothers display identifiably different communicative styles in their interaction with their normally developing two- to five-year-old children. In order to investigate this issue an extensive coding system was developed, which assessed the structural organization and the communicative function of the speech of 71 mothers as they interacted with their children. By means of factor analysis three maternal communicative styles were distinguished: non-intervening, explaining and directing. In the non-intervening style there is no direct pressure from the mother on the child to respond verbally. The explaining mother is primarily concerned with providing information to her child in a way that gives the child little opportunity to take the speaking turn. The directing mother is mainly engaged in directing the child's behaviour by means of verbal control. The internal consistency of the three communicative styles appeared to be both satisfactory and related to relevant child and mother features.
BACKGROUND AND OBJECTIVES: We performed two retrospective chart surveys, the first of 200 consecutive hospital emergency visits for spontaneous abortion and the second in 33 family physicians' offices examining 245 patients with spontaneous abortions. This study determined the rate of surgical management of spontaneous abortions within family practices and hospitals, as well as the rate of referrals and complications. METHODS: In the retrospective chart surveys, the information collected included the number of spontaneous abortions, dilation and curettages (D&Cs), referrals, and complications. RESULTS: Of the women presenting to the hospitals, 92.5% had D&Cs, while 51% of the women presenting to family physicians had D&Cs. Of the women presenting to the hospitals, 99.5% were referred to gynecologists, compared with 41% of the family practice patients. Hemorrhage occurred in 4.6% of the hospital patients and 2% of the family practice patients. Infection occurred in 6% of the hospital patients and .8% of the family practice patients. CONCLUSIONS: Patients with spontaneous abortions who saw their family physicians were more likely to be managed conservatively than those seen in the hospitals. There was no increase in complications in the conservatively managed patients.
The recently reported chemotaxonomic and genotypic description of two well-separated subgroups (I and II) in Aeromonas eucrenophila and their affiliation to Aeromonas encheleia and the unnamed Aeromonas DNA hybridization group (HG) 11 (G. Huys, M. Altwegg, M.-L. Hänninen, M. Vancanneyt, L. Vauterin, R. Coopman, U. Torck, J. Lüthy-Hottenstein, P. Janssen, and K. Kersters, Syst. Appl. Microbiol. 19:616-623, 1996) has questioned the original species descriptions of A. eucrenophila and A. encheleia. In order to elucidate the unclear taxonomic status of these taxa in the genus Aeromonas, we have further investigated a collection of 14 reference strains and 14 related isolates encompassing the taxa A. eucrenophila subgroups I and II, A. encheleia, and HG11 by DNA-DNA hybridization (on 17 of the 28 strains) and phenotypic characterization (on all 28 strains). Genotypically, the investigated strains could be grouped into two DNA hybridization groups that exhibited between-group homologies ranging from 42 to 52%. The members of DNA homology group I (DNA binding, 76 to 100%) were strains of A. eucrenophila subgroup I, including the type strain LMG 3774, and two A. eucrenophila-like isolates, leading to the conclusion that these strains should be considered true representatives of the species A. eucrenophila. The strains of A. eucrenophila subgroup II, HG11, and A. encheleia, on the other hand, were closely joined in DNA homology group II (DNA binding, 74 to 105%) together with two presumptive A. encheleia isolates. The fact that strain LMG 16330T of A. encheleia was the only type strain residing in DNA homology group II implies that HG11 and A. eucrenophila subgroup II should be classified in the species A. encheleia. Except for the somewhat aberrant phenotypic positions of HG11 strains LMG 13075 and LMG 13076, the establishment of DNA homology groups I and II was supported by the delineation of phena 1 and 2 (level of correlation, 90%), respectively, as revealed by numerical analysis of 136 phenotypic test results. These data indicate that A. eucrenophila and A. encheleia are phenotypically highly related but can be easily separated by testing the production of acid from D-cellobiose and lactose and the assimilation of D-cellobiose. Extended descriptions of both species are given.
We examined the taxonomic position of seven Aeromonas isolates, recovered from Flemish and Scottish drinking water production plants and reservoirs, which were previously recognized by numerical analysis of genomic AFLP fingerprints as members of an unknown Aeromonas taxon that most closely resembled the species Aeromonas bestiarum (DNA hybridization group [HG] 2). The new phenotypic and DNA-DNA hybridization data obtained in this study show that the A. bestiarum-like strains constitute a separate Aeromonas species, for which the name Aeromonas popoffii sp. nov. is being proposed. The new species exhibited an internal DNA relatedness ranging from 79 to 100% and was 22 to 63% related to the type or reference strains of other Aeromonas spp. The highest DNA binding values were determined with A. bestiarum (51 to 63%), followed by Aeromonas hydrophila sensu stricto (HG1; 50 to 60%) and Aeromonas salmonicida (HG3; 39 to 55%). Although fingerprints generated by ribotyping and cellular fatty acid analysis often were highly similar, minor differences between the respective fingerprints were of significance for the differentiation of A. popoffii from its closest taxonomic neighbors, HG1, HG2, and HG3. Phenotypically, all seven strains of A. popoffii were positive for acid and gas production from D-glucose and glycerol, growth in KCN broth, arginine dihydrolase, DNase, Voges-Proskauer reaction, and resistance to vibriostatic agent O/129 and ampicillin but displayed negative reactions for production of urease, tryptophan deaminase, ornithine decarboxylase, and lysine decarboxylase (LDC). None of the strains displayed strong hemolytic activity. The lack of D-sucrose fermentation and LDC production and the ability to utilize DL-lactate as the sole energy and carbon source were useful characteristics for the biochemical separation of A. popoffii from A. bestiarum. Other Aeromonas spp. could be differentiated phenotypically from the new species by at least two features. The chromosomal G+C content of A. popoffii ranges from 57.7 to 59.6 mol%. Strain LMG 17541 is proposed as the type strain.
AFLP is a novel genomic fingerprinting method based on the selective PCR amplification of restriction fragments. The usability of this method for the differentiation of genomic species in the genus Acinetobacter was investigated. A total of 151 classified strains (representing 18 genomic species, including type, reference, and field strains) and 8 unclassified strains were analyzed. By using a single set of restriction enzymes (HindIII and TaqI) and one particular set of selective PCR primers, all strains could be allocated to the correct genomic species and all groups were properly separated, with minimal intraspecific similarity levels ranging from 29 to 74%. Strains belonging to genomic species 8 (Acinetobacter lwoffii sensu stricto) and 9 grouped together in one cluster. The closely related DNA groups 1 (Acinetobacter calcoaceticus), 2 (Acinetobacter baumannii), 3 and 13TU (sensu Tjernberg & Ursing 1989) were clearly distinguishable, with intraspecific linkage levels above 50%. Strains of the independently described genomic species 13BJ (sensu Bouvet & Jeanjean 1989) and 14TU linked together at a relatively low level (33%). Although a previous DNA-DNA hybridization study seemed to justify the unification of these genomic species, AFLP analysis actually divides the 13BJ-14TU group into three well-separated subgroups. Finally, four unclassified strains obtained from diverse sources and origins grouped convincingly together, with a similarity linkage level of approximately 50%. These strains showed no similarities in their AFLP patterns with any of the other 155 strains studied and may represent a thus-far-undescribed Acinetobacter species. Based on these results, AFLP should be regarded as an important auxiliary method for the delineation of genomic species. Furthermore, because AFLP provides a detailed insight into the infraspecific structure of Acinetobacter taxa, the method also represents a highly effective means for the confirmation of strain identity in the epidemiology of acinetobacters.