Tissue distribution of human gamma delta T cells: no evidence for general epithelial tropism.

In man and mice only a small proportion of T cells in the peripheral lymphoid compartment express the gamma delta T cell receptor (TCR). In mice, however, gamma delta T cells comprise the predominant population at particular epithelial sites--in epidermis and epithelia of intestine, reproductive organs, and tongue. The distribution of gamma delta T cells in normal human tissues was investigated, paying particular attention to epithelial layers. In all lymphatic organs and in epithelia of a wide variety of non-lymphatic organs, including the respiratory tract, male and female reproductive organs and tongue, gamma delta T cells constituted less than 5% of total T cells, with the remainder expressing TCR alpha beta. The only exception was the intestine, where gamma delta T cells were preferentially situated in the columnar epithelium of the crypts, rather than in the lamina propria. It is concluded, therefore, that human gamma delta T cells do not display a general epithelial tropism and are, in terms of relative numbers, no more able than alpha beta T cells to carry out continuous surveillance of the immune system against infection or transformation in epithelia. gamma delta T cells may, however, have a specialised function in the epithelium of the intestinal tract.

Polymerase chain reaction for the detection of Helicobacter pylori in formaldehyde-sublimate fixed, paraffin-embedded gastric biopsies.

To improve morphologic detail and immunohistochemical staining, mercuric chloride-containing fixatives such as formaldehyde-sublimate (FS) has been widely used as an alternative for neutral buffered formalin. FS-fixed, paraffin-embedded tissue, however, is considered to be an unreliable source of DNA. We used an adapted DNA-extraction method for FS-fixed, paraffin-embedded tissue. In all cases tested we obtained amplifiable DNA with polymerase chain reaction (PCR), after FS-fixation and after fixation in neutral buffered formalin as well. A PCR assay for the 16S-rRNA region of Helicobacter pylori was developed amplifying a fragment of 145 bp. The specificity of this PCR assay was tested on a range of different microorganisms. PCR was performed on 46 archival FS-fixed paraffin-embedded gastric biopsies. The results were compared with histologic examination and with immunohistochemical detection using a polyclonal antibody against H. pylori. Both PCR and immunohistochemistry are very sensitive methods for the detection of H. pylori. A PCR offers the possibility of additional subtyping in archival FS-fixed, paraffin-embedded tissue.

Genotyping of Helicobacter pylori strains in formalin-fixed or Formaldehyde-sublimate-fixed paraffin-embedded gastric biopsy specimens.

Different genotypes of Helicobacter pylori can play a role in the development of atrophic gastritis, peptic ulcer disease, and gastric carcinomas. In this study the authors developed polymerase chain reaction assays for the detection and identification of vacA (s- and m-regions), cagA, and iceA genotypes of H. pylori in formalin-fixed or formaldehyde-sublimate-fixed paraffin-embedded gastric biopsy specimens. Polymerase chain reaction products were analyzed by reverse hybridization on a line-probe assay. Complete genotyping was achieved in 26 of 28 samples (93%), and multiple genotypes, indicating the presence of multiple strains, were detected in nine samples (32%). This genotyping method offers the possibility for long-term retrospective studies on H. pylori genotypes and gastric pathology in the same archival gastric tissue specimens.

Experimental gingivitis in relation to age in individuals not susceptible to periodontal destruction.

The purpose of the present investigation was to study the effect of age on the rate of development of gingival inflammation in individuals not susceptible to periodontal destruction. 7 younger (mean age 37 years) and 7 older (mean age 58 years) individuals were selected on the basis of the presence of at least 18 teeth, no evidence of extraction due to periodontal destruction, no loss of attachment, shallow pockets, gross amounts of plaque and a history of no interdental cleaning. All individuals were subjected to a carefully controlled oral hygiene program and experimental gingivitis was induced in 1 quadrant of the mouth during a period of 33 days. The amount of plaque, redness and swelling of the gingiva, and bleeding on probing were assessed before, during and after the experiment. At day 33, supra-gingival plaque samples were taken for bacteriological examination and gingival biopsies were taken for histopathological and immunohistochemical investigation. Results showed no differences between the 2 age groups with regard to the amount of plaque accumulation and the rate of development of gingival inflammation. Furthermore phase-contrast microscopy of plaque samples showed no differences between the 2 age groups. Neither histological nor immunohistochemical investigation showed any differences between the 2 age groups. All biopsies diffusely showed presence of IgG, whereas in most biopsies, IgA plasma cells and in one biopsy IgM plasma cells were found. Neither IgD, IgE nor complement deposits were found. It was concluded that age is of minor importance in the development of experimentally-induced gingivitis in individuals not susceptible to periodontal destruction.

The use of antibodies to intermediate filament proteins in the differential diagnosis of lymphoma versus metastatic carcinoma.

Forty-nine cases encompassing 16 different types of malignant lymphoma were examined for their intermediate filament protein (IFP) type by indirect immunofluorescence microscopy of cryostat sections. In all cases, vimentin was shown to be the only IFP type detectable in these tumours. Lymphomas are negative for keratin and desmin, which are characteristic for benign and malignant epithelial or muscular tissues respectively. In addition, eighteen cases are described in which antibodies to intermediate filament proteins were used successfully to distinguish between lymphoma and metastatic carcinoma where differential diagnosis was difficult or impossible on the basis of routine histology.

Experimental gingivitis in relation to susceptibility to periodontal disease. II. Phase-contrast microbiological features and some host-response observations.

In the present investigation, a number of histological and immunohistochemical characteristics of periodontal tissues as well as the phase-contrast microscopy of dental plaque were studied after experimentally-induced gingival inflammation in relation to susceptibility to periodontal disease. The study included a younger (mean age 34.1 years) and an older age group (mean age 48 years) with a reduced but healthy periodontium. Both age groups had the same amount of loss of attachment which may suggest that they had different degrees of susceptibility to periodontal disease. At the start of the experiment, each patient was instructed to abstain from oral hygiene in one quadrant of the mouth for a period of 18 days. At the end of the 18-day period, supra-gingival plaque and gingival tissue samples were taken. As determined by phase-contrast microscopy, the plaque samples of both age groups contained relatively high proportions of spirochetes. This may indicate that the patients are at risk for recurrence of periodontal breakdown. The general histopathologic picture of the gingival tissue samples of both age groups was similar to the so-called 'early lesion'. However, IgA-producing plasma cells were found in most tissue samples of both age groups. The first part of this study showed that the younger, in comparison to the older, patients developed inflammation in terms of bleeding on probing more rapidly. These clinical results cannot be explained by the host-parasite parameters investigated in the present study.

Bleeding/plaque ratio and the development of gingival inflammation.

In a recent publication, it was hypothesized that the ratio between bleeding and plaque scores may act as a prognostic indicator for periodontal breakdown. Furthermore, it was found that the rate of development of gingival inflammation in terms of bleeding on probing during experimental gingivitis is more rapid in patients susceptible to periodontal breakdown than in subjects insusceptible to periodontal breakdown. The purpose of the present investigation was to compare the gingival reaction to dental plaque in an experimental gingivitis study in individuals without periodontal breakdown, having either a low or a high bleeding/plaque ratio. A group of 8 volunteers (18-23 years) with a low bleeding/plaque ratio and 7 volunteers (19-22 years) with a high bleeding/plaque ratio were selected. In both groups, an experimental gingivitis study of 23 days duration was carried out. Results showed that individuals with a high bleeding/plaque ratio developed significantly more clinical inflammation in terms of bleeding and swelling of the gingiva than individuals with a low bleeding/plaque ratio. After 23 days of plaque accumulation, gingival biopsies as well as supragingival plaque samples were taken from both groups. Phase-contrast microscopy of the plaque samples showed no significant differences between the 2 groups. Low %s of spirochetes and motile rods were found. Stereologic point-counting procedures showed equal amounts of infiltrated connective tissue in both groups. However, significant differences in composition of the infiltrate appeared to be present. The high ratio group showed more IgA producing plasma cells and complement activation than the low ratio group.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative analysis of human papillomavirus infections in cervical scrapes and biopsy specimens by general SPF(10) PCR and HPV genotyping.

Human papillomavirus (HPV) can be detected by DNA amplification from clinical samples. The aim of the present study was to compare the HPV status in both cervical scrape and biopsy specimens obtained from 174 patients, using the recently developed broad spectrum SPF(10) PCR-LiPA method. The detection rate of HPV in these materials was determined and the spectrum of HPV genotypes was compared. Cervical scrapes and biopsy specimens were obtained, either on the same day (group I), or with an interval of up to almost 2 years (group II, mean interval 97 days, range 1-469 days). HPV DNA was amplified by SPF(10) PCR and detected in a microtitre plate hybridization assay. Of the HPV-positive cases, the genotype was determined by reverse hybridization of the same SPF(10) amplimer on a line probe assay (LiPA), discriminating between HPV genotypes 6, 11, 16, 18, 31, 33-35, 39, 40, 42-45, 51-54, 56, 58, 59, 66, 68, 70, and 74. The results showed that the detection rate and the spectrum of HPV genotypes in cervical scrapes and the corresponding biopsy specimens were highly comparable in both patient groups, even when multiple genotypes were present. In both groups, multiple HPV genotypes were more frequently detected in cervical scrapes than in the corresponding biopsy specimens. In conclusion, HPV infection can be diagnosed in cervical scrapes and biopsy specimens using the SPF(10) PCR-LiPA system. Analysis of cervical scrapes accurately reflects the spectrum of HPV genotypes in the patient's cervical region, even with a sampling interval between the cervical scrape and the biopsy specimen.

Determination of transferrin receptors on frozen sections of malignant B-cell lymphomas by immunofluorescence with a monoclonal antibody.

A series of 34 B-cell lymphomas was studied for the presence of transferrin receptors by immunofluorescence on frozen tissue sections with a monoclonal antibody. These lymphomas were classified by light microscopic study and furthermore investigated by immunohistochemical and morphometric methods. There were diffuse centrocytic, diffuse centroblastic, and follicular and diffuse centrocytic/centroblastic lymphomas. Significant differences in log mean nuclear area in these four histologic groups were found, as well as a significant correlation between log nuclear area and transferrin receptors as measured semiquantitatively by fluorescence intensity of the cell membranes. In addition, it was found that there is a strong correlation between the transferrin receptor activity and malignancy grading on histologic and morphometric basis. Therefore, the transferrin receptor determination on frozen sections appears to be a good method of malignancy grading.

Helicobacter pylori-related and -non-related gastric cancers do not differ with respect to chromosomal aberrations.

Gastric carcinogenesis is strongly associated with Helicobacter pylori infection, but the underlying genetic mechanisms are largely unknown. The aim of this study was to correlate chromosomal aberrations in gastric cancer to H. pylori status and its different strains, as well as to histological type and other clinico-pathological variables. DNA from 46 gastric cancers (male/female 35/11, age 27-85 years) was extracted from formaldehyde-fixed, paraffin-embedded material and tested for chromosomal gains and losses by comparative genomic hybridization (CGH). Chromosomal aberrations with frequencies of 20% or higher were considered to be non-random changes associated with gastric cancer. The mean number of chromosomal events per tumour was 9.7 (range 0-27), with a mean of 3.2 gains (range 0-16) and 6.5 losses (range 0-15). Gains were most frequently found at chromosomes 8q and 13q (24% and 26%, respectively). Losses were predominantly found on chromosome arms 2q, 9p, 12q, 14q, 15q, 16p, 16q, 17p, 17q, 19p, 19q, and 22q (22%, 30%, 43%, 22%, 33%, 50%, 28%, 50%, 39%, 33%, 39%, and 37%, respectively). Common regions of overlap narrowed down to 2q11-14, 8q23, 9p21, 12q24, 13q21-22, 14q24 and 15q11-15. The mean number of gains was higher in tumours with metastases than in localized tumours (4.1 vs. 1.9, p=0.04). Tumours with a loss at 17p showed a higher number of losses than tumours without a 17p loss (9. 5 vs. 4.7 on average, p<0.001). Neither H. pylori status (+, n=25; -, n=21) nor H. pylori strain was correlated to the total number of events or to any specific chromosomal aberration, nor were there differences between intestinal (n=30) and diffuse (n=15) cancers or any other clinico-pathological variable tested. In conclusion, a complex of chromosomal aberrations is involved in gastric cancer, but their pattern does not depend on H. pylori status or strain, nor on the histological type of the tumour. The exact biological meaning of these aberrations in carcinogenesis needs further clarification.