Prenatal diagnosis of a supernumerary aberrant chromosome 9

For counselling of parents, as well as to basically understand how chromosome aneuploidies affect embryonic or fetal development, it is of great importance to analyse and collect genotypes of fetuses with clinical anomalies. This report describes the first prenatal diagnosis of a supernumerary chromosome 9 with deletion of the chromosome region 9q34. Ultrasound examination in the 13th week of gestation detected increased nuchal translucency of 6.9 mm, fetal ascites and a pronounced facial anomaly. Hysteroscopic examination before curettage made it possible to describe this facial anomaly as a double-sided, median defect of the superior lip with protrusion of parts of intersegments. This report provides evidence that the absence of trisomy 9 in 9q34 does not prevent abnormal facial development.     

Relaxographic studies of aging normal human lenses

Ten excised normal human lenses of various ages were studied. Seven sections of each lens, from anterior outer cortex to posterior outer cortex were imaged and the T(1) (spin-lattice) and T(2) (spin-spin) relaxation data on each section were collected. T(1) and T(2) relaxation were analysed by fitting pixel intensity to one term exponential expressions. Both T(1) and T(2) relaxation times showed minimal values in the nuclear region and maxima at the two outer cortexes. The pre-exponential terms of the fittings of both T(1) and T(2) relaxation,M(1) and M(2), were normalized in order to eliminate instrumental variations over a 2 year period. M(2) had a maximum in the nucleus and minima in the two cortexes. M(1) exhibited minimal value in the nucleus and maxima at the two cortexes. The positional dependence of T(2) relaxation times as well as that of M(2) indicated that they represent the behavior of the bound water in the lens. The positional dependence of M(1) suggests that this relaxation represents the total water that has a minimal value in the nucleus. The T(2) relaxation time decreases with increase in the age of the lens at each location. The slope of the change in T(2) relaxation time with age is greatest in the outer cortexes and diminishes as one proceeds to the nucleus. T(1) relaxation times and M(1) do not show significant change with age. This and the age dependence of the other relaxographic parameters imply that the aging of the lens involves major changes in its hydration properties that are more accentuated in the cortexes. The interpretation of these changes is in agreement with the syneretic theory of lens aging.     

The blood-aqueous barrier and its permeability for proteins of different molecular weight

Summary In aqueous humors and sera from 44 patients with cataracts, albumin, IgG, and -1-antitrypsin were measured using radial immunodiffusion. The mean concentrations of the three proteins were significantly smaller than values found in aqueous humors taken post mortem, but corresponded well to values found in cerebrospinal fluid. No statistically significant difference was found between men and women, normotensives and hypertensives, and patients with or without myopia of higher degree (> 6 diopters). A slight increase in protein concentrations in older patients and a relative decrease of -1-antitrypsin is described. The aqueous humor-serum quotients of the different proteins showed a higher correlation than did the concentration of the proteins in aqueous humors.

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Zusammenfassung Im Kammerwasser und Serum von 44 an Cataract operierten Patienten wurden mit Hilfe der radialen Immundiffusion Albumin, IgG und -1-Antitrypsin bestimmt. Die Mittelwerte waren gegenüber Werten im KW, das post mortem gewonnen wurde, deutlich erniedrigt, stimmen jedoch gut mit den Normwerten des Liquor cerebrospinalis überein. Es fand sich kein statistisch gesicherter Unterschied zwischen Männern und Frauen, Hypertonikern und Normotensiven, sowie Myopen (über 6 dptr) und Patienten mit nur geringen Brechungsfehlern. Es ließ sich jedoch ein schwacher Anstieg der Proteinkonzentrationen im höheren Alter sowie eine relative Verminderung von -1-Antitrypsin feststellen. Es besteht eine engere Korrelation zwischen den KW-Serum-Quotienten der einzelnen Proteine, als zwischen den Konzentrationen der Proteine im KW selbst.

     

Virulence properties and serotypes of Shiga toxin-producing Escherichia coli from healthy Australian slaughter-age sheep

A group of 1,623 ovine fecal samples recovered from 65 geographically distinct mutton sheep and prime lamb properties across New South Wales, Australia, were screened for the presence of Shiga toxin-producing Escherichia coli (STEC) virulence factors (stx(1), stx(2), eaeA, and ehxA). A subset was cultured for STEC isolates containing associated virulence factors (eaeA and/or ehxA), which were isolated from 17 of 20 (85%) and 19 of 20 (95%) tested prime lamb and mutton sheep properties, respectively. STEC isolates containing stx(1), stx(2), and ehxA were most commonly isolated (19 of 40 flocks; 47.5%), and this profile was observed for 10 different serotypes. Among 90 STEC isolates studied, the most common serotypes were O91:H(-) (22 isolates [24.4%]), O5:H(-) (16 isolates [17.8%]), O128:H2 (11 isolates [12.2%]), O123:H(-) (8 isolates [8.9%]), and O85:H49 (5 isolates [5.6%]). Two isolates (2.2%) were typed as O157:H(-). A total of 78 of 90 STEC isolates (86.7%) expressed Shiga toxin in Vero cell culture and 75 of 84 ehxA-positive isolates (89.3%) expressed enterohemolysin on washed sheep blood agar. eaeA was observed in 11 of 90 (12.2%) ovine STEC isolates, including serotypes O5:H(-), O84:H(-), O85:H49, O123:H(-) O136:H40, and O157:H(-). Although only 2 of 90 isolates were typed as O157:H(-), the predominant serotypes recovered during this study have been recovered from human patients with clinical disease, albeit rarely.     

Colonization of the respiratory tract by a virulent strain of avian Escherichia coli requires carriage of a conjugative plasmid

The E3 strain of E. coli was isolated in an outbreak of respiratory disease in broiler chickens, and experimental aerosol exposure of chickens to this strain induced disease similar to that seen in the field. In order to establish whether the virulent phenotype of this strain was associated with carriage of particular plasmids, four plasmid-cured derivatives, each lacking two or more of the plasmids carried by the wild-type strain, were assessed for virulence. Virulence was found to be associated with one large plasmid, pVM01. Plasmid pVM01 was marked by introduction of the transposon TnphoA, carrying kanamycin resistance, and was then cloned by transformation of E. coli strain DH5alpha. The cloned plasmid was then reintroduced by conjugation into an avirulent plasmid-cured derivative of strain E3 which lacked pVM01. The conjugant was shown to be as virulent as the wild-type strain E3, establishing that this plasmid is required for virulence following aerosol exposure. This virulence plasmid conferred expression of a hydroxamate siderophore, but not colicins, on both strain E3 and strain DH5alpha. Carriage of this plasmid was required for strain E3 to colonize the respiratory tracts of chickens but was not necessary for colonization of the gastrointestinal tract. However, the virulence plasmid did not confer virulence, or the capacity to colonize the respiratory tract, on strain DH5alpha. Thus, these studies have established that infection of chickens with E. coli strain E3 by the respiratory route is dependent on carriage of a conjugative virulence plasmid, which confers the capacity to colonize specifically the respiratory tract and which also carries genes for expression of a hydroxymate siderophore. These findings will facilitate identification of the specific genes required for virulence in these pathogens.     

A novel serotype of enteropathogenic Escherichia coli (EPEC) as a major pathogen in an outbreak of infantile diarrhoea

An outbreak of infantile diarrhoea was investigated in 32 children, all <2 years old, in the tropical north of Australia. Rotavirus (63%) and enteropathogenic Escherichia coli (EPEC) (59%) were the most common pathogens identified. Of the 19 EPEC isolates, 14 (74%) were of serotype O126:H12, hitherto unreported as an EPEC serotype. Other pathogens isolated included Salmonella spp. (16%), Campylobacter spp. (3%), Giardia (3%) and Shigella spp. (3%). EPEC-related gastro-enteritis is an uncommon but recognised cause of diarrhoeal outbreaks in Australia and clinicians need to be aware of the possibility of this serotype being implicated. This report highlights the disadvantages of relying on serotyping alone for the recognition of EPEC.     

Phenotypes of Human Large Granular Lymphocytes as Defined by Monoclonal Antibodies

Four monoclonal antibodies VEP8, VEP9, VIM-D5, VIB-C5 against antigens expressed on human mature myeloid cells (polymorphonuclear leukocytes [PMNL] and/or monocytes) as well as on immature cells in the bone marrow were tested for reactivity with cell preparations highly enriched for large granular lymphocytes (LGL). These cells are known to be the main effector cells responsible for natural killer (NK) cell activity in human peripheral blood. Using indirect membrane immunofluorescence (IMF), none of these antibodies showed any reactivity at all. In addition, LGL-enriched cell preparations were tested with the anti-lymphocyte monoclonal antibodies OKT6, anti-Leu1, anti-Leu2a, anti-Leu3a, and anti-human Lyt3, and also with OKM1 antibody. Significant reactivity was found with anti-Leu2a (59 ± 8 %), anti-Lyt3 (55 ± 4 %) and OKM1 (81 ± 11 %) antibodies, whereas T6, Leu1, and Leu3a antigens were less pronounced or missing on LGL. As a further approach, another monoclonal antibody, VEP13, which reacts with LGL, granulocytes but not monocytes and is therefore different in its specificity from OKM1 and OKT10, was used for identification of LGL. The coexpression of antigens as defined by the above-mentioned antibodies and OKT10 on VEP13⁺ cells was studied. Again, phenotypes similar to those observed on LGL enriched by Percoll^® gradient centrifugation were found: of VEP13⁺ cells 84 ± 6 % reacted with OKM1, 82 ± 5 % with OKT10, 52 ± 17 % with anti-human Lyt3, and 48 ± 14 % with anti-Leu2a, whereas VEP8, VEP9, VIM-D5, VIB-C5, T6, Leu1, Leu3a antigens were not expressed on VEP13⁺ cells. Taken together as an overall evaluation of phenotypic characteristics, our data indicate that LGL cannot be integrated into one of the known lymphocytic or myelomonocytic lineages. LGL show an intermediate phenotype depending possibly on varying differentiation or activation stages of haemopoietic cells. However, the possibility also exists that LGL belong to a separate, yet undefined cell lineage.     

Controlled study of cytolethal distending toxin-producing Escherichia coli infections in Bangladeshi children.

The role of cytolethal distending toxin (CDT)-producing Escherichia coli, a newly described category of E. coli, in the causation of diarrhea was studied by screening E. coli isolates from 546 children < 5 years of age with diarrhea and 215 matched controls without diarrhea by using a specific DNA probe. Although CDT-positive E. coli strains were isolated from more children with diarrhea than from healthy controls (3.1 versus 0.93%), this difference did not reach statistical significance (P = 0.082). All CDT-positive strains also possessed the virulence factors of enteropathogenic E. coli or enteroaggregative E. coli isolates.     

Evaluation of the Phadebact ETEC-LT test for the heat-labile enterotoxin of Escherichia coli

The Phadebact ETEC-LT is a rapid method of identifying enterotoxigenic Escherichia coli (ETEC), producing the heat-labile enterotoxin (LT). It uses staphylococcal coagglutination as a means of identifying the LT released from ETEC. In this investigation both known strains of ETEC from a variety of sources as well as strains from patients were tested. Good agreement was found between the Phadebact ETEC-LT test and established tests for LT. The test was found easy to use in the clinical laboratory environment, and revealed that LT producing ETEC may be more common causes of diarrhoea in Australia than had been anticipated.     

Molecular characterisation of verocytotoxin-producing Escherichia coli of serogroup O111 from different countries.

A collection of epidemiologically unrelated verocytotoxin (VT)-producing Escherichia coli (VTEC) strains of serogroup O111 isolated from human patients and cattle with diarrhoeal disease in five different countries were characterised by determination of their VT genotypes, the presence of other virulence factors such as the intimin-coding eae gene and the enterohaemorrhagic E. coli (EHEC) plasmid, and their antibiotic susceptibility patterns. The genetic relatedness among isolates was evaluated by genomic DNA fingerprinting techniques such as restriction fragment length polymorphism analysis of ribosomal RNA genes (ribotyping) and pulsed-field gel electrophoresis. The results indicated that the VTEC O111 examined belong to two distinct clonal lineages. The first group was constituted mainly of non-motile, eae-positive, EHEC plasmid-positive isolates from both man and cattle. The second lineage was represented by an O111:H2 epidemic strain, isolated during an outbreak of haemolytic uraemic syndrome in France and exhibiting an unusual combination of virulence factors: VT production and aggregative adhesion to HEp-2 cells associated with an enteroaggregative E. coli (EAEC) plasmid.