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Biomedical subjects

J Lindeman

Publications and source records attributed to J Lindeman.

At least 19 recordsLinked to original sources

Fibroblast-like synoviocytes from rheumatoid arthritis patients have intrinsic properties of follicular dendritic cells.

The production of IgG rheumatoid factors in the inflamed synovium of many patients with rheumatoid arthritis (RA) implies that local sites exist where plasma cell precursors undergo isotype switching and affinity maturation by somatic mutation and selection. Lymphonodular infiltrates of the synovium-containing germinal centers (GCs), are candidates to fulfill such function in the rheumatoid patient. It has been suggested that these GCs are organized around, obviously ectopic, follicular dendritic cells (FDCs). The present study attempts to find out whether these putative FDCs 1) are specific for RA, 2) have the same phenotype and functional capacity as FDCs in lymphoid organs, and 3) may locally differentiate from fibroblast-like synoviocytes (FLS). Synovial biopsies from patients with RA versus non-RA, yet arthritic backgrounds, were compared. Cells with the FDC phenotype were found in both RA and non-RA tissues as well as in single cell suspensions thereof. When FLS were cultured in vitro, part of these cell lines could be induced with IL-1beta and TNF-alpha to express the FDC phenotype, irrespective of their RA or non-RA background. By contrast, the FDC function, i.e., stable binding of GC B cells and switching off the apoptotic machinery in B cells, appeared to be the prerogative of RA-derived FLS only. The present data indicate that FDC function of FLS in RA patients is intrinsic and support the idea that synovial fibroblast-like cells have undergone some differentiation process that is unique for this disease.

Adult

Trends in hospitalization and mortality from rotavirus disease in New Zealand infants.

BACKGROUND: Rotavirus illness is associated with significant morbidity and mortality worldwide. We have examined trends in diarrheal disease in New Zealand children to determine the disease burden attributable to rotavirus and to estimate the proportion of hospitalizations preventable by vaccination. METHODS: Hospital admissions data and laboratory records for 1994 to 1996, were obtained for children 0 to 4 years at four sites (serving -60% of the New Zealand population). Rotavirus disease burden was estimated using combined admissions and laboratory data. Severity of disease was estimated in a sample of 150 hospitalizations for rotavirus diarrhea, and the proportion of vaccine-preventable admissions was extrapolated. Mortality attributed to diarrheal causes was determined from national records for 1974 to 1993. RESULTS: Between 1994 and 1996, 4436 children <5 years of age were hospitalized with diarrhea (1047/100000 children per year). Admissions associated with rotavirus were estimated at 1522 to 1535 (315 to 362/100000 annually). Infants between 6 and 17 months were most commonly affected (42% of all cases). More male children than female children were hospitalized (P < 0.001) and mean length of stay was calculated as 1.51 days (SD 2.35). Disease severity scoring revealed that 61.3 and 38.0% of admissions reviewed were severe and very severe, respectively. Deaths from diarrheal causes numbered 138 among children 0 to 4 years old for the 20-year period 1974 to 1993, with 18 deaths occurring between 1984 and 1993 (10 years). CONCLUSION: Current vaccines control severe disease, suggesting that 72% of cases reviewed would be eligible for prevention. A full cost effectiveness analysis is required to demonstrate anticipated benefits of vaccination.

Child, Preschool

Development and clinical evaluation of a highly sensitive PCR-reverse hybridization line probe assay for detection and identification of anogenital human papillomavirus.

Human papillomavirus (HPV) can be detected by amplification of viral DNA. A novel PCR primer set generating a short PCR fragment (SPF PCR) was used for amplification of a fragment of only 65 bp from the L1 region and permitted ultrasensitive detection of a broad spectrum of HPV genotypes. The intra- and intertypic sequence variations of the 22-bp interprimer region of this amplimer were studied. Among 238 HPV sequences from GenBank and clinical specimens, HPV genotypes were correctly identified based on the 22-bp sequence in 232 cases (97.2%). Genotype-specific probes for HPV genotypes 6, 11, 16, 18, 31, 33 to 35, 39, 40, 42 to 45, 51 to 54, 56, 58, 59, 66, 68, 70, and 74 were selected, and a reverse hybridization line probe assay (LiPA) (the INNO-LiPA HPV prototype research assay) was developed. This LiPA permits the use of amplimers generated by the SPF as well as the MY 09/11 primers. The assay was evaluated with a total of 1, 354 clinical specimens, comprising cervical scrapes (classifications ranging from normal cytology to severe dyskaryosis) and formalin-fixed, paraffin-embedded cervical carcinoma samples. LiPA results were highly concordant with sequence analysis of the SPF amplimer, genotype-specific PCR, and sequence analysis of amplimers generated by MY 09/11 primers. The sensitivity of the SPF primers was higher than that of the GP5(+)/6(+) primers over a broad range of HPV types, especially when multiple HPV genotypes were present. In conclusion, the SPF LiPA method allows extremely sensitive detection of HPV DNA as well as reliable identification of HPV genotypes in both cervical smears and paraffin-embedded materials.

Base Sequence

Immunohistochemical localization of somatostatin receptor sst2A in human rheumatoid synovium.

OBJECTIVE: To identify the somatostatin receptor-expressing cells in rheumatoid synovium using a recently developed antiserum directed against the somatostatin receptor subtype 2A (sst2A). METHODS: We carried out immunohistochemical studies of synovial biopsies from 7 patients with rheumatoid arthritis (RA) and one non-RA patient, using a rabbit polyclonal antiserum directed against sst2A and monoclonal antibodies directed against phenotypic markers. RESULTS: SSt2A was expressed by the endothelial cells of the synovial venules but also by a subset of synovial macrophages. CONCLUSION: The identification of somatostatin receptors on macrophages, which are thought to be important effector cells in RA, may offer mechanistic insights into the potential therapeutic effect of somatostatin (analogs) in RA.

Animals

Monoclonal antibodies against the human mannose receptor as a specific marker in flow cytometry and immunohistochemistry for macrophages.

Recently we developed mouse monoclonal antibodies (mAb) against the isolated human 175-kDa mannose receptor. In the present study we tested whether these mAb are suitable for the detection of the mannose receptor on cultured macrophages using flow cytometry and on cells in human tissues using immunohistochemistry. Human monocytes did not react with the mAb in flow cytometry. Mannose receptor expression became detectable on monocytes cultured for 3 days (macrophages), and was maximal from 4 days onward. The mannose receptor was up-regulated on dexamethasone-treated (immunosuppressed) macrophages, and down-regulated on lipopolysaccharide-treated (activated) macrophages. Immunohistochemically the staining pattern of our mAb was compared with the marker of monocytes/macrophages KP1. In a bone marrow smear, only macrophages were stained with our mAb, whereas all myeloid cells were stained with KP1. In the thymus and lymph node, mannose receptor-positive branched cells (macrophages and dendritic cells) were detected in connective tissue, thymus cortex (not medulla), and in the T cell area (not the B cell area) of lymph nodes, whereas KP1 stained branched cells in all areas. It was concluded that the mAb are useful tools in flow cytometry and immunohistochemistry for the specific detection of cells expressing mannose receptor.

Antibodies, Monoclonal

Growth factor profiles of human gliomas. Do non-tumour cells contribute to tumour growth in glioma?

BACKGROUND: Growth factors play a role in proliferation and motility of malignant glial cells, through autocrine and paracrine mechanisms. Also, proliferation of non-tumour cells, e.g., endothelial cells, is likely to be controlled by growth factors. Several growth factors with their appropriate receptors can be involved, but studies on tissue specimens evaluating this in glioma are rare. MATERIALS AND METHODS: We evaluated the potential role of Transforming growth factor-alpha (TGF-alpha) and Epidermal growth factor receptor (EGF-R), the Platelet-derived growth factor A- and B-chain (PDGF-A and PDGF-B) and its receptors (PDGFR alpha and PDGFR beta, and basic fibroblast growth factor (bFGF) in gliomas by analysing 86 of these tumours on the single cell level for the presence of immunoreactive growth factors and receptors. In a few cases double-staining experiments were done to directly visualize co-expression of factor and receptor. RESULTS: Multiple growth factors and their receptors are present in astrocytic tumours; the higher the grade, the more growth factors and the more positive cells are found. Oligodendroglial tumours and pilocytic astrocytomas showed little expression. Autocrine and paracrine mechanisms were frequently possible in the astrocytic tumours, often more than one loop could be involved. Interestingly, it was also frequently possible that non-tumour cells produced a growth factor for which the tumour cells expressed the receptor. CONCLUSIONS: Multiple growth factors appear to be involved in astrocytic tumours, with frequent autocrine and paracrine loops. Expression of these molecules seems to increase with increasing grade. The results argue for a contribution of non-tumour cells to the growth of a tumour.

Astrocytoma

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.

Biopsy

Malabsorption syndrome associated with ulceration of the stomach and small bowel caused by chronic intestinal ischemia in a patient with hyperhomocysteinemia.

We describe a 39-year-old woman with an 8-month history of abdominal pain, diarrhea, and weight loss. Clinical and laboratory evaluation indicated the presence of a malabsorption syndrome. Endoscopy revealed multiple gastric ulcerations and an abnormal "picture" of the duodenal mucosa. At duodenal biopsy, necrosis confined to the distal parts of the enteric villi and a polymorphonuclear leukocyte response were found. Further evaluation revealed intestinal ischemia as a result of mesenteric atherosclerosis. After a revascularization procedure was performed, the symptoms disappeared. The macroscopic and microscopic picture of the bowel normalized. In our search for risk factors of atherosclerosis, we found a substantially increased basal plasma homocysteine concentration. This case suggests that hyperhomocysteinemia may have a causal role in the development of symptomatic, premature atherosclerosis of the mesenteric circulation.

Adult

Serological parameters in assessment of degree of gastritis in healthy volunteers.

This study was undertaken in healthy volunteers to determine the relation between serum levels of pepsinogen A, pepsinogen C, pepsinogen A:C ratio, and gastrin on the one hand and histology of the gastric mucosa on the other. The grade of gastritis was scored separately for antral and fundic mucosa by three different classifications: Whitehead, activity, and the Sydney score. Among 48 healthy volunteers studied, 17 were found to have gastritis according to the criteria of Whitehead. Fourteen of these 17 subjects with gastritis had H. pylori in gastric biopsies. In all 48 subjects serum pepsinogen A (r = 0.298-0.506; P < 0.01-P < 0.05), pepsinogen A:C ratio (r between -0.377 and -0.495; P < 0.001-P < 0.05) and gastrin (r = 0.38-0.695; P = 0.007-P < 0.01) were significantly correlated to the severity of both antral and body gastritis as assessed by all three classifications. In contrast, there was no significant correlation between serum pepsinogen C and any of the gastritis scores. When the 17 subjects with gastritis were analyzed separately, there were no correlations between the parameters studied and gastritis of the antrum. Regarding the corpus mucosa, serum PgA correlated significantly with the activity score (r = 0.520; P = 0.03), weakly with the Sydney score (r = 0.465; P = 0.06), but not with the Whitehead score. Serum PgC correlated with the Whitehead (r = 0.555; P = 0.02) and Sydney score (r = 0.523; P = 0.03), but only weakly with the activity score (r = 0.441; P = 0.08).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Increase of Helicobacter pylori-associated corpus gastritis during acid suppressive therapy: implications for long-term safety.

OBJECTIVES: Helicobacter pylori causes chronic active gastritis with predominant localization in the gastric antrum. This predisposes to development of mucosal atrophy, intestinal metaplasia, and eventually, gastric cancer. The effects of acid suppression on H. pylori infection and associated gastritis are unclear. However rapid development of atrophic gastritis has been consistently observed in a number of studies during low acid output. We therefore studied the histological features of antrum and corpus of the stomach before and during acid suppressive therapy. METHODS: Fifty patients with either reflux esophagitis (n = 21), benign gastric ulcer (six patients), gastric erosions (three patients), or duodenal ulcer (20 patients) were treated for 8 wk with omeprazole 40 mg o.d. Esophagogastroduodenoscopy was performed pre-entry and at 8 wk. Biopsy specimens were sampled from the antrum and corpus for histology and cultures. RESULTS: Seventeen H. pylori-negative patients had no histological signs of active gastritis, before or after therapy. Thirty-three H. pylori-positive patients showed predominant colonization and associated inflammation in the antrum before therapy. After therapy, however, the infection predominantly affected the corpus. The inflammation and bacterial colonization in the antrum significantly decreased, leading to negative antral cultures in 61% (20 of 33 patients). In contrast, the inflammation of the corpus mucosa significantly increased despite stable bacterial counts. CONCLUSIONS: We conclude 1) that H. pylori testing in patients on profound acid suppressive therapy should be performed on combined corpus and antral specimens, and 2) that omeprazole therapy leads to a strong increase in corpus gastritis, which may explain the observed development of corpus atrophy in a substantial number of patients after several years of continuous acid suppressive treatment. Therefore, we suggest that patients in need of long-term acid suppressive therapy should receive bacterial eradication therapy if they are H. pylori positive.

Antacids

Syntactic context effects on word recognition: a developmental study.

In the present study, grammatical context effects on word recognition were examined among skilled and less skilled second and sixth grade readers. Of particular interest was how the word decoding ability may correlate with the grammatical context effect. For this purpose the rich case-marking system of the Finnish language was exploited. Recognition latencies for sentence-final nouns were measured as a function of their syntactic agreement with the preceding adjective. The naming and lexical decision tasks were used as critical measures. The study showed a clear syntactic context effect for each of the four experimental groups. The magnitude of the observed syntactic effect was substantially larger compared to earlier results. Furthermore, the effect emerged both in naming and lexical decision. In naming, less skilled 2nd grade decoders were more affected by grammatical incongruency than their more competent peers, whereas in lexical decision the skilled 6th graders differed from other groups by showing a smaller syntactic effect. The results are discussed in the light of Stanovich's interactive-compensatory model of word recognition.

Adolescent

Relation between IgG and IgA antibody titres against Helicobacter pylori in serum and severity of gastritis in asymptomatic subjects.

AIMS: To investigate whether the absorbance index of IgG and IgA antibodies against Helicobacter pylori is related to a semiquantitative assessment of the density of H pylori colonisation in gastric biopsy specimens and to the severity of gastritis. METHODS: The grade of gastritis was scored separately for antral and fundic mucosa using three different classifications. Serum IgA and IgG antibodies against H pylori were measured by ELISA. The density of gastric H pylori colonisation was graded semiquantitatively from 0 to 3. RESULTS: Among 48 healthy volunteers studied, 17 were found to have gastritis according to Whitehead's criteria. H pylori was present in the biopsy specimens of 14 of 17 subjects with gastritis. The IgG H pylori antibody absorbance index was significantly (p < 0.05) correlated not only with the density of antral H pylori colonisation, but also with the degree of gastritis of the antrum, as assessed by the Whitehead score, activity, and the Sydney system (p < 0.05). The IgA H pylori antibody absorbance index was significantly correlated with the Whitehead score and Sydney system, but not with the activity score of the antrum or with the density of antral gastric H pylori infection. There were no significant correlations between the IgG H pylori antibody absorbance index and the gastritis scores of the fundus mucosa and the density of H pylori infection of the gastric body. The IgA H pylori antibody absorbance index was only significantly (p < 0.05) correlated with the density of H pylori colonisation and the Sydney system gastritis score of the corpus. CONCLUSIONS: The serological absorbance index of IgG antibodies against H pylori is related to the severity of antral gastritis and the density of antral H pylori colonisation. Thus a high absorbance index of IgG antibodies against H pylori points to severe antral gastritis and dense H pylori colonisation of the antrum.

Adult

Flow cytometric DNA content of fresh tumor specimens using keratin-antibody as second stain for two-parameter analysis.

Studies concerning flow cytometric assessed DNA content reveal problems in interpretating DNA histograms of tumor specimens. The main problems are histograms with a broad coefficient of variation in the G0/G1 fraction; a high G2M fraction and samples with a low percentage of tumor cells. Therefore, in the present study, 382 fresh tumor specimens of carcinomas were analysed routinely, double labeled with, on the one hand, propidium-iodide for assessing DNA content and, on the other, a monoclonal keratin-antibody for marking epithelial and tumor cells. Of the 311 tumor samples, using single parameter analysis 165 (54%) were classified as DNA aneuploid and 146 (46%) as DNA "euploid." By double parameter analysis, 224 (72%) samples were keratin positive and 87 (27%) keratin negative and, of the 224 keratin positive tumors, 175 (78%) were DNA aneuploid and 49 (22%) DNA euploid. The DNA histograms of single and double parameter analysis were compared and it was concluded that in 24 cases (11%) keratin labeling was necessary to recognize DNA aneuploidy. In another 23 (10%) cases, keratin labeling was helpful in assessing DNA aneuploidy. Finally when the results of the 311 samples were combined, 215 (68%) were scored as DNA aneuploid and 99 (32%) DNA euploid. Thus the overall gain in assessing DNA aneuploidy using the double labeling technique is 14%. In conclusion, it is shown that keratin labeling on fresh tumor cell suspensions of epithelial tumors is of additional value in establishing DNA content. Because single parameter DNA assessment is adequate in approximately 60% of the tested samples, the double labeling technique can be performed routinely, or after initial single parameter DNA assessment. Histograms having a broad CV and/or a high G2M are good candidates for the double labeling technique. Using this technique, DNA-content assessment becomes more reliable.

Antibodies

Value of counting colonic mucosal Ig-containing cells in the differential diagnosis of chronic inflammatory bowel disease.

AIMS: To investigate whether counting cells containing immunoglobulin (Ig) subclass in colonic biopsy specimens of patients with chronic inflammatory bowel disease, in addition to conventional histological evaluation, can improve the differentiation of patients with Crohn's disease from those with ulcerative colitis. METHODS: The colonic and rectal biopsy specimens of 40 patients with chronic inflammatory bowel disease, comprising 20 patients with Crohn's disease and 20 with ulcerative colitis, were used and sections were stained specifically for IgA, IgM, and IgG heavy chains using an indirect immune peroxidase method. The immunoglobulin subclass containing cells were counted using an ocular grid counting method in a light microscope. A linear stepwise discriminant analysis was performed on Ig subclass containing cell counts in combination with 16 reproducible histological features. The results of this discriminant analysis were compared with the results of the discriminant analyses in which only the histological features were used. RESULTS: Applying stepwise discriminant analysis, two histological features (an excess of histiocytes in the lamina propria and the villous or irregular aspect of the mucosal surface) in combination with IgMax were selected as the most discriminatory parameters that distinguish Crohn's disease from ulcerative colitis. IgMmax was defined as the maximum value of the mean percentage of IgM containing cells over all the biopsy locations. The use of this combination resulted in a better classification in 20% of the patients with Crohn's disease and in 9% of the patients with ulcerative colitis compared with the use of histological features alone. CONCLUSIONS: Morphometric enumeration of Ig subclass containing cells in colonic mucosal biopsy specimens has diagnostic value as a means of differentiating individual patients with Crohn's disease from those with ulcerative colitis.

Adolescent

Human papillomavirus and the three group metaphase figure as markers of an increased risk for the development of cervical carcinoma.

In this study, the presence of atypical mitotic figures and human papilloma virus (HPV) genomes was related to the degree of cervical intraepithelial neoplasia (CIN) or microinvasive carcinoma (MIC) as found in 94 paraffin-embedded biopsies from cervical lesions. The results showed that the frequency of three group metaphase (TGM) figures, a special kind of atypical mitotic figure, as well as the presence of HPV 16 and 18 genomes increased with the degree of cervical intraepithelial neoplasia. TGM figures were observed in 24% of CIN2, up to 61% in CIN3 lesions, and in 83% of the microinvasive cervical carcinomas. HPV genomes were detected in 15% of CIN1, up to 75% in CIN3 lesions, and in 92% of the invasive carcinomas of the cervix. The combination of these two markers showed even a better association with a higher degree of cervical intraepithelial neoplasia. The results of these studies suggest that detection of particular HPV types, mainly HPV 16 and 18, and the presence of TGM figures can be considered as markers that indicate an increased risk for progression of cervical intraepithelial neoplasia to invasive carcinoma.

Carcinoma in Situ

Towards a quantitative grading of bladder tumors.

The histological inspection of tumor tissue for the purpose of reporting a tumor grade is a problem of significant clinical importance. The grading by a pathologist is only partly reproducible due to vaguely defined, subjective criteria. In this article we describe and evaluate a set of measurable features that quantitate the differences in tumor tissue. Different aspects of the reproducibility of the measurements under varying conditions of image selection, focus, and noise have been investigated. Three hundred thirty-three images were digitized from 111 bladder tissue sections (4 microns thick, Feulgen stained), using the ICAS microscope-camera platform. A segmentation routine was developed to segment the images into nuclei and background without any user interaction. Size, shape, optical density, and texture features were measured on and among the objects found by this segmentation routine using the image analysis package Acuity. The results of the measurements showed that there is a significant quantitative difference between grade 1 and grade 3 tumors. Grade 2 tumors can be described as "in between grade 1 and grade 3" and falling somewhere on an increasing scale between grades 1 and 3. Grade 2 tumors do not seem to represent a statistically distinct population. The procedure described here is shown to be quite reproducible in the presence of noise, reasonably reproducible in the event of a modest amount of defocusing (with grade 3 tumors exhibiting the most sensitivity), and less reproducible in the context of which fields-of-view are chosen for analysis.

Epithelium

Histopathological evaluation of colonic mucosal biopsy specimens in chronic inflammatory bowel disease: diagnostic implications.

In a prospective blind evaluation of multiple colonic mucosal biopsy specimens, 45 clinically well defined patients with chronic inflammatory bowel disease (21 Crohn's disease and 24 ulcerative colitis) and 16 control subjects (seven normal subjects and nine patients with diverticular disease) were studied to identify reproducible histopathological features which could distinguish chronic inflammatory bowel disease (CIBD) from non-CIBD and Crohn's disease from ulcerative colitis. Using kappa statistics 16 of 41 histological features were sufficiently reproducible for further stepwise discriminant analysis to differentiate between CIBD and non-CIBD, and between Crohn's disease and ulcerative colitis. Using the combination of three features (an increase of lymphocytes and plasma cells in the lamina propria, the presence of branching of crypts, and neutrophils in the crypt epithelium) we were able to distinguish CIBD from non-CIBD in 89% of the cases with high probability (p greater than 0.85). To separate Crohn's disease from ulcerative colitis three features (an excess of histiocytes in combination with a villous or irregular aspect of the mucosal surface and granulomas) had a high predictive value. Using these features 70% of Crohn's disease patients and 75% of ulcerative colitis patients were correctly classified with a high probability (p greater than 0.85). These findings indicate that the pathologist is dependent on the presence of only a few histological features for a reliable classification of Crohn's disease and ulcerative colitis.

Adult

Detection of Chlamydia trachomatis in clinical specimens by the polymerase chain reaction.

Sequences derived from the endogenous plasmid of Chlamydia trachomatis and from the genes coding for ribosomal 16S RNA of Chlamydia psittaci were used as primers and oligonucleotide probes for detection of chlamydiae by the polymerase chain reaction. The endogenous plasmid primers generated specific amplified products of 517 bp with all known Chlamydia trachomatis serovars. No specific products of Chlamydia psittaci and Chlamydia pneumoniae could be detected using these primers. With the rRNA primers specific amplified products of 208 bp were generated with Chlamydia psittaci, Chlamydia trachomatis and Chlamydia pneumoniae. No specific amplified products were detected with DNA isolated from a variety of microorganisms from the urogenital and the respiratory tract. Of 156 clinical specimens used for evaluation of the polymerase chain reaction, 26 were found to be positive for Chlamydia trachomatis on culture. All 26 culture positive samples were also found to be positive for Chlamydia trachomatis DNA by the polymerase chain reaction with both primer sets. Two culture negative samples were also found to be positive by this technique. The polymerase chain reaction thus seems to be a sensitive and reliable method for detection of Chlamydia trachomatis.

Base Sequence