Apmis

Viola, Antonella; Lanzavecchia, Antonio

doi: 10.1111/j.1699-0463.1999.tb01450.xpmid: 10440056

Recent evidence, indicates that T‐cell receptor (TCR) triggering and T‐cell activation are dynamic processes that involve various aspects of T‐cell organization. In addition to the interaction between the TCR molecule and its ligand, T‐cell activation depends on a combination of many other events involving coreceptor molecules, actin cytoskeleton and plasma membrane lipids. Altogether, these cell structures organize the formation of a specialized junction between the T cell and the antigen‐presenting cell (APC), that plays a critical role in sustaining and amplifying TCR signalling.

Jacquet, Ch.; Thierry, D.; Veit, P.; Guesdon, J.‐L.; Rocourt, J.

doi: 10.1111/j.1699-0463.1999.tb01451.xpmid: N/A

A Listeria monocytogenes UNA fragment, identified as part of the 23S rRNA gene and called B17, was used to type 266 L. monocytogenes strains and 43 strains of other Listeria species. Results were compared with those obtained: i) with pBA2 (which consists of a 2.3 kb Bacillus subtilis DNA fragment encoding 16S rRNA, inserted into the HinIII site of pBR322), a probe previously used for Listeria and L. monocytogenes ribotyping, and ii) with DNA macrorestriction profiles analysis. Twenty profiles were identified for L. monocytogenes using pB17, three of which accounted for 87% of strains. This new rDNA probe had greater discriminatory power for serogroups 1/2 or 3 strains than for serogroup 4 strains. The number of varieties and the discrimination index were higher with this new probe than with pBA2, but DNA macrorestriction patterns analysis gave better discrimination between strains.

Visfeldt, J.; Cortes, D.; Thorup, J. M.; Byskov, A. G.

doi: 10.1111/j.1699-0463.1999.tb01452.xpmid: 10440058

MIC2 is a pseudoautosomal gene localized on X and Y chromosomes. The MIC2 gene product is a glycoprotein expressed on the cell membranes of a number of somatic cells, including Sertoli cells of the testis, but not on the cell membranes of germ cells. In cases of cryptorchidism, a testicular biopsy is recommended in order to evaluate future fertility potential. The spermatogonia are identified on histological sections and the number per tubular transverse section is compared with normal values for age. The patient is at 33–100% risk of subsequent infertility when the number of spermatogonia per tubular transverse section is lower than 1% of the lowest normal age‐matched value. Besides Sertoli cells the seminiferous tubules in undescended testes contain only a few germ cells, and it may be difficult to pinpoint the germ cells in small biopsies. Especially in nonpalpable testes their number may be heavily reduced. A reliable identification of germ cells may also be difficult in cultures of testicular biopsies from undescended testes. Against this background, we tried the use of an immuno‐histochemical method with DAKO antibody to the MIC2 gene product (MIC2, 12 E7, code no. M3601) in order to obtain a “negative reaction” of germ cells, contrasting with the stained Sertoli cells. The material comprised: 44 specimens of testicular parenchyma taken at time of surgery for cryptorchidism from 24 cryptorchid boys with nonpalpable testes and 14 testicular biopsies from 13 cryptorchid patients with palpable testes which had been cultured in vitro for 7, 14 or 21 days. In all cases the immunohistochemical method with DAKO antibody to the MIC2 gene product was helpful for identification of Sertoli cells and germ cells, and we therefore recommend the use of anti‐MIC2 in all testicular biopsies where it is difficult to pinpoint the germ cells.

Lauritzen, Anne F.; Møller, Peter Horn; Nedergaard, Trine; Guldberg, Per; Hou‐Jensen, Klaus; Ralfkiaer, Elisabeth

doi: 10.1111/j.1699-0463.1999.tb01453.xpmid: 10440059

During recent years it has become increasingly evident that L&H cells in nodular lymphocytic predominance (LP) Hodgkin's disease (HD) and Hodgkin and Reed‐Sternberg (H‐RS) cells in approximately half the cases of classical HD originate from B‐lymphocytes, and that H‐RS cells in most of the remaining cases of classical HD express a null phenotype. The pathogenesis of HD is unknown. An association with Epstein‐Barr virus (EBV) has been suggested and there are also indications that genes involved in programmed cell death (apoptosis) may be implicated. In this study, the expression of four apoptosis‐related proteins (bcl‐2, bcl‐x, bax and p53) in 53 cases of HD was examined and the data were correlated with the genotype, the EBV status and the phenotype (B, T or null) of the neoplastic cells. The H‐RS cells expressed a B‐cell phenotype in 3/3 cases of nodular LP and in 19/50 (38%) cases of classical HD. The remaining cases showed a null‐cell phenotype in 29/50 (58%) and a T‐cell phenotype in 2/50 (4%). EBV was more often positive in B (14/19, 74%) than in null (7/29, 24%) type HD. The H‐RS cells were bcl‐2‐positive in 19/53 (36%), bcl‐x‐positive in 17/53 (32%), bax‐positive in 1/53, and p53‐positive in 41/53 (77%) cases. No relationship was found between bcl‐2 expression and EBV status, or between bcl‐2 and bcl‐x expression. A t(14;18) translocation was seen in 2 of 34 cases. P53 point mutations were not detected. Our findings indicate that nodular LP and classical HD originate from B‐cells in a high proportion of cases. They also suggest a role for bcl‐2, bcl‐x and p53 in tumorigenesis. The pathogenesis is not known at this stage.

Tetz, VIctor V.

doi: 10.1111/j.1699-0463.1999.tb01454.xpmid: 10440060

Mixed bacterial communities are formed by unrelated bacteria on solid media. Mixed bacterial communities on solid media are similar to “classical” colonies and are formed after the growth of a large number of unrelated bacteria simultaneously plated onto a limited area of agar. The morphology of the mixed bacterial communities was similar for different combinations of bacteria and did not change when the bacteria were plated on different media. Different bacterial strains form zones of individual and mixed growth in the structure of mixed bacterial communities. The results of electron microscopic examination indicate that mixed bacterial communities are isolated from their external environment by a surface film. The basic part of this film is formed by an elementary membrane. The membrane of the surface film of mixed bacterial communities is a stable structure occupying a large surface area. The results of this investigation seem to indicate the existence of a special type of co‐operation between different species of bacteria. This type of co‐operation may be very important in the regulation of interactions between different bacteria and between bacteria and the environment.

Grönlund, Minna‐Maija; Salminen, Seppo; Mykkänen, Hannu; Kero, Pentti; Lehtonen, Olli‐Pekka

doi: 10.1111/j.1699-0463.1999.tb01455.xpmid: 10440061

To evaluate the development of intestinal flora in young infants, and especially to estimate the influence of mode of delivery and type of feeding on the establishment of intestinal microflora, faecal flora was studied indirectly by measuring prospectively the faecal bacterial enzyme activities (β‐glucosidase, β‐glucuronidase and urease) in 29 full‐term, healthy infants during the first 6 months of life. Mode of delivery had no influence on the faecal enzyme activities. In contrast, infants receiving formula feeds were more often urease positive at 1–2 months of age (70%vs 25%, p=0.043) and had higher median activity of β‐glucuronidase at 6 months of age (0.90 and 0.19 nmoles/mg protein × min, p=0.0043) than exclusively breast‐fed infants. Through indirect methods to measure the development of a faecal microflora our results indicate that the type of milk that infants receive during the first months of life may have an important role in the development of intestinal flora.

Hacsek, Gabor; öRmäLä, Timo; Rintala, Risto; Savilahti, Erkki

doi: 10.1111/j.1699-0463.1999.tb01456.xpmid: 10440062

The development of B‐cells and immunoglobulin‐isotype and IgA subclass‐positive cells in the lamina propria of the large intestine during infancy was investigated. Biopsy specimens from 36 infants, taken for diagnostic purposes, were available. All samples showed normal morphology. Monoclonal antibodies to CD22, IgA, IgA1, IgA2, IgM and IgG and a peroxidase method were used to demonstrate positive cells in the cryostat sections. Cell densities were counted from a known area. T‐cells had been measured in a previous study using the same specimens. The density of CD22+ cells was already high in infants below the age of 1 month and increased little with age. Four specimens from infants below the age of 40 days lacked IgA‐, IgA1‐ and IgA2‐positive cells. The densities of these cells increased with age; the correlation coefficient between the age and the density of the cells was for IgA: R = 0.47, p=0.04; for IgA1: R=0.57, p=0.001, and for IgA2: R=0.34, p=0.04. The densities of IgG‐ and IgM‐positive cells remained unchanged with age. The negative correlation between density of IgG+cells and CD8+ cells in the lamina propria (R=‐0.43, p=0.01) was significant. Strong local stimulation results in early accumulation of CD22+, IgM+ and IgG+ cells in the large intestine, but little change takes place after the first few days of life. The terminal differentiation to IgA‐positive cells is slowest, and this population showed significant developmental change.

Hansen, H.; Sandvik, T.; Tryland, M.; Olsvik, ø.; Traavik, T.

doi: 10.1111/j.1699-0463.1999.tb01457.xpmid: 10440063

During the last decades, cowpox virus, a member of the genus Orthopoxvirus within the Poxviridae family, has appeared as a pathogen in domestic cats, zoo animal species, and humans. At the same time, vaccinia virus, another orthopoxvirus, has been used as a recombinant vaccine vector with foreign genes inserted in the thymidine kinase (TK) gene. By PCR and cycle sequencing, we have determined the nucleotide sequences of the TK gene and the A‐type inclusion protein (ATIP) gene of virus isolates from two human cowpox cases in Sweden, as well as a human and a feline case from Norway. We also obtained the corresponding sequences from ectromelia virus (strain Moscow), cow‐pox virus (strain Brighton) and vaccinia virus (strain Western Reserve). The new virus isolates differed from ectromelia virus and vaccinia virus, and were confirmed to be cowpox virus strains. Isolates originating from the same country had nearly identical TK sequences and fully identical ATIP sequences. They probably represent local geographical strains of cowpox virus.

Baerheim, Anders; Digranes, AsbjøRn; Hunskaar, Steinar

doi: 10.1111/j.1699-0463.1999.tb01458.xpmid: 10440064

During 7 months from August 1994, 171 urine samples were collected consecutively in general practice in Western Norway from female patients with suspected lower urinary tract infection. For each of the 171 samples, 2 samples from adult females received from general practice at the microbiological laboratory on the same day were selected using a predetermined system. Samples noted as treatment controls and samples from pregnant patients were discarded. Bacteriuria was found in 101/171 (59.1%) vs 220/342 (64.3%) of the samples. The general practice material contained more bacteriuric samples with Escherichia coli (83.2% vs 71.8%, p<0.05) and Staphylococcus saprophyticus (11.9 vs 6.4%), and fewer with other Gram‐negative rods (4.0% vs 15.9%, p<0.01) and enterococci (1.0% vs 5.9%, p<0.01). The frequency of resistant isolates was substantially lower in the samples from general practice for all antibacterial agents tested: amoxycillin 18.9% vs 23.9%, mecillinam 1.1% vs 4.7%, trimethoprim 12.9% vs 18.5%, cotrimoxazole 12.0% vs 15.4%, sulphonamide 20.0% vs 28.4%, nitrofurantoin 3.0% vs 9.7% (p<0.05). Data from local laboratories exaggerate the resistance problems among uropathogens found in urine samples in general practice.

Vasei, Mohammad; Imanieh, Mohammad Hadi

doi: 10.1111/j.1699-0463.1999.tb01459.xpmid: N/A

Fungal colonization was observed in the duodenal biopsy specimens of a nine‐year‐old girl who complained of anorexia and epigastric pain. Endoscopy revealed gastric redness and Geotrichum candidum was identified in the duodenum by histopathology and tissue culture. Immunologic work‐up showed low serum levels of IgA and IgM. She was treated with ranitidine and antacids for gastritis. At follow‐up, the levels of immunoglobulins had normalized, no fungal elements were detected, and clinical symptoms had disappeared. Duodenal invasion by G. candidum has not been described so far. Duodenal colonization by G. candidum may occur when mucosal immunity is disturbed and may be the source of dissemination in severe immunodeficiency states.