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Biomedical subjects

L A Rogers

Publications and source records attributed to L A Rogers.

At least 19 recordsLinked to original sources
PubMed1998

Expression of oestrogen receptor and oestrogen-inducible genes pS2 and ERD5 in large bowel mucosa and cancer.

Since there is a preponderance of large bowel cancer in males, both in humans and in experimental models, and hormone replacement therapy is protective, a role for sex steroid hormones in the pathogenesis of this neoplasm seems likely. Evidence of functional oestrogen receptor has been looked for in large bowel mucosa and cancer. Expression of oestrogen receptor, and of the oestrogen-inducible receptor-associated genes pS2 and ERD5, was sought. Oestrogen receptor mRNA was detected in cancers and paired normal mucosae in equal amounts. In situ hybridization identified stromal cells above the muscularis mucosae that were positive for oestrogen receptor mRNA. pS2 mRNA was also detected, with a signal intensity significantly higher in normal mucosa compared with cancers, whereas the reverse was seen with ERD5 mRNA levels. pS2 and ERD5 were expressed in epithelium, with the former in a greater amount in distal colon and rectum than proximal colon. Although oestrogen-inducible and receptor-associated genes are expressed in large bowel mucosa, their expression does not correlate with oestrogen receptor.

Aged↗
PubMed1998

A robust method for isotopic riboprobe in situ hybridisation to localise mRNAs in routine pathology specimens.

In situ Hybridisation (ISH) to detect mRNA is widely applicable to studies of human pathology and experimental models including transgenic mice, where it can provide crucial information as to where a gene is expressed, that is not available in other ways. ISH was used to establish that relatively high levels of expression of E-cadherin mRNA were associated with long-term survival in colorectal cancer, before suitable antisera became available. There is increasing awareness that ISH can be used to help select between candidate disease genes found at a linked locus, and that ISH can help validate therapeutic targets. For instance, when several closely related receptor genes are expressed in a tissue, it may be possible to determine which combinations are expressed together in a single cell type. These diverse applications demand a robust method that works on a variety of clinical and experimental materials, and is easily interpreted. To date, the ICRF in situ Hybridisation Service has hybridised over 30,000 sections of principally formalin-fixed, paraffin-embedded tissues, with a high success rate. The practicalities of our preferred method are discussed and key steps for quality control highlighted.

Automation↗
PubMed1998

Comparison of isotopic and non-isotopic labelling for in situ hybridisation of various mRNA targets with cRNA probes.

In situ hybridisation methods to localise messenger ribonucleic acid (mRNA) targets in tissue sections or cell preparations using riboprobes can be successful with either isotopic or non-isotopic labelling. Investigators often wish to decide which labelling method provides the maximum specificity, sensitivity and resolution, with minimum nonspecific background. In this study we compared isotopic (35S) and non-isotopic (digoxigenin) labelling, using a variety of probes and paraffin-embedded tissues. The targets were human beta-actin and von Willebrand Factor mRNAs in archival human tissues; and mRNAs for two closely related trefoil factor family (TFF) peptides, TFF2 and TFF3, in rat duodenum. Patterns of localisation with both isotopic and non-isotopic probes were broadly similar for each target. The 35S labelling provided good contrast and sensitive detection under darkfield illumination, but the cellular or subcellular resolution of the target was less precise than that obtained with the digoxigenin-labelled probes in transmitted light. Digoxigenin labelling in individual cells was more clearly demonstrated, but occasionally the contrast of positive staining with background was poor. The sensitivity of each method appeared to be similar for these high-abundance targets, therefore the choice between isotopic and non-isotopic labels is dependent upon the aim of the study and the cellular resolution required.

Animals↗
PubMed1997

Diagnostic accuracy of a rural live video telepathology system.

Accuracy of diagnoses rendered using a live video telepathology network was assessed for permanent sections of surgical pathology specimens. To determine accuracy, telepathology diagnoses were compared with those obtained by directly viewing the glass slide using a standard microscope. A total of 294 cases were read via both telepathology and glass slide by attending pathologists at a tertiary care medical center. Overall accuracy was defined as exact concordance between diagnoses. Clinically insignificant differences in diagnoses were excluded to determine clinically significant accuracy. For the 285 cases with complete data, the overall accuracy for telepathology was 0.912 (95% confidence interval [CI], 0.872-0.941), whereas the overall accuracy for glass slide readings was 0.968 (95% CI, 0.939-0.985). This difference is statistically significant (p = 0.009). When focusing on clinically significant discrepancies, where the difference in diagnosis might affect therapeutic decisions, the video accuracy was only slightly less than the glass slide accuracy (0.965 [95% CI, 0.934-0.982] vs. 0.982 [95% CI, 0.957-0.994], respectively), but this difference is not statistically significant (p = 0.302). Most of the cases with clinically significant differences involved lesions with inherently high interobserver variation. Certainty of diagnosis did not differ between video and glass slide readings (p = 0.911), but there was an association between certainty of diagnosis and diagnostic accuracy for video (p = 0.003 for clinically significant accuracies). Based on these findings, we recommend when using this telepathology system that only preliminary diagnoses should be given in the following situations: for diagnostic areas with known high interobserver variability; when the consultant has any degree of uncertainty about the presence or absence of the lesion in question; and when there is insufficient experience using telepathology as a diagnostic medium.

Crohn Disease↗
PubMed1993

hP1.B, a human P-domain peptide homologous with rat intestinal trefoil factor, is expressed also in the ulcer-associated cell lineage and the uterus.

The six-cysteine P-domain motif forms the basic repeat unit of a growing family of mucin-associated peptides. A precursor for a human secretory polypeptide has been discovered by molecular cloning and deduced to have a single P-domain, termed hP1.B. The pre-pro-peptide has 67% amino acid identity with rat intestinal trefoil factor. We find, using the techniques of RNA analysis and in situ hybridization, that this P-domain peptide is expressed in the human gastrointestinal tract, where a number of pathological conditions affect its expression, and surprisingly find it is expressed in the uterus also. In the intestine, hP1.B is expressed by goblet cells, but in Crohn disease this peptide is synthesized and secreted additionally by the ulcer-associated cell lineage that is known to secrete two other trefoil peptides, pS2 and spasmolytic polypeptide (hSP). In the stomach, hP1.B mRNA is relatively scarce but is more abundant in foci of intestinal metaplasia and near to ulceration. Mucin-rich epithelial cells in hyperplastic polyps of the colon also express this peptide. The discovery of this P-domain peptide and its expression in association with mucins support the hypothesis that P-domains with mucins may subserve related functions in the maintenance and repair of mucosal function.

Amino Acid Sequence↗
PubMed1992

Localization of intestinal trefoil-factor mRNA in rat stomach and intestine by hybridization in situ.

A cDNA encoding rat intestinal trefoil factor (rITF) was prepared by reverse transcription and PCR amplification. The sequence obtained was well conserved with that of other trefoil peptides. An antisense riboprobe produced from the clone was used to localize the sites of ITF expression in the rat gastrointestinal tract using hybridization in situ. We found rITF mRNA in goblet cells in the small intestine and colon; a gradient of signal strength greatest near the crypt base was sometimes present. We found no evidence for rITF expression in Brunner's glands, the pancreas, or most regions of the gastric mucosa. Surprisingly, strong signals for rITF mRNA were detected in a region of stomach at the junction of the squamous fore-stomach with the glandular gastric mucosa. This region, which may correspond to the cardiac region, formed part of a larger area of cells staining positive for acid mucins. We hypothesize that concerted expression occurs of particular trefoil peptides with specific mucins, and that this organization reflects a functional relationship between mucins and trefoil peptides.

Amino Acid Sequence↗
PubMed1992

Murine cytolytic CD8+ T cell clones generated in a high cloning efficiency, accessory cell-free culture system express a restricted lymphokine profile.

To determine whether cytolytic T lymphocyte activity is associated with a particular lymphokine profile, lymphokine synthesis was analyzed in a large panel of primary clones derived from single murine CD8+ lymph node T cells. The clones were generated at high efficiency (60-70%), under conditions that had been optimized for the induction of specific cytolytic activity, by culture with phorbol 12-myristate 13-acetate, ionomycin, IL-2, and IFN-gamma for 6 days and then with IL-2 and IL-6 for a further 2 days. When the clones were restimulated for 24 hr with IL-2 and immobilized antibodies to CD3, CD8, and LFA-1, most secreted IL-3 and IFN-gamma and about a third secreted TNF. Although levels of production of IL-3 and IFN-gamma were positively correlated with each other (r = 0.85) and weakly correlated with cytolytic activity (r = 0.68 and 0.55, respectively). TNF titers were unrelated to any other function measured. None of the clones tested secreted detectable IL-4 or IL-6. Similarly, analysis of several clones for lymphokine mRNA expression following cDNA amplification by the polymerase chain reaction revealed the presence of IL-2, IL-3, IFN-gamma, TNF-alpha, and GM-CSF but not IL-4 or IL-6 transcripts. Cytolytic CD8+ T cell clones generated in this high efficiency, accessory cell-independent cloning system therefore expressed a restricted lymphokine profile characterized by the synthesis of IL-3 and IFN-gamma, with variable production of TNF.

Animals↗
PubMed1992

Quantitative analysis of lymphokine expression in vivo and in vitro.

Constitutive lymphokine production by cells isolated from mice injected with keyhole limpet haemocyanin (KLH) or from mice undergoing an acute graft vs host reaction (GVHR) was very low, but could be markedly increased by T cell receptor (TCR) ligation. This suggested that in vivo levels of lymphokine production are much lower than those induced by in vitro stimulation. Serum lymphokine titres were consistent with this possibility, and analysis of lymphokine mRNA levels using S1-nuclease protection demonstrated that in vitro-stimulated cells from normal, KLH and GVHR mice all had markedly increased levels of lymphokine transcripts relative to levels found in vivo. A novel method combining limiting dilution analysis with polymerase chain reaction amplification of cDNA was developed that showed that these differences in levels of lymphokine production were due at least in part to differences in the frequencies of lymphokine mRNA-containing cells. Studies of the means by which differential lymphokine production is achieved demonstrated that CD4+, CD8+ and cytotoxic T lymphocyte (CTL) clones all express a common, restricted set of lymphokines in response to a defined in vitro stimulus, but that individual in vivo primed cells can express at least seven distinct patterns of lymphokine production.

Animals↗
PubMed1992

Breast carcinoma simulating fibroadenoma or fibrocystic change by fine-needle aspiration. A study of 16 cases.

The cytologic features of fine-needle aspiration specimens from 16 breast carcinomas that closely simulated benign lesions were analyzed and compared to smears from fibroadenomas and fibrocystic change. No combination of features was found that accurately separated all benign and malignant cases. Many nuclei with discernible small nucleoli in smears with many single bipolar nuclei indicated a benign lesion, whereas nuclear hyperchromasia indicated a malignant one.

Adenofibroma↗
PubMed1992

How the door opened: the peopling of the New World.

The timing, pathways, and number of migrations involved in the early peopling of the New World are examined from a variety of perspectives. Ultimately, the occupation of the Western Hemisphere was a direct result of boreal cultural adaptations in the Old World. Here, we discuss (1) the dates of appearance of these boreal cultural adaptations and their relevance to the peopling of America, (2) archeological and linguistic evidence bearing on the earliest peopling of the New World, (3) ecological and linguistic evidence on two alternative routes into the New World, and (4) the assumptions present in various migration models. The relative strengths of opposing hypotheses are analyzed by observing whether different approaches point to the same answers.

Anthropology, Cultural↗
PubMed1991

The maintenance of lytic specificity during the development of clones of cytotoxic T lymphocytes from single precursor cells.

A high-cloning efficiency, filler cell-free limit-dilution culture system for the growth and differentiation of single cytotoxic T lymphocyte precursors (CTLp) was tested for its ability to maintain the lytic specificity of the resultant clones of cytotoxic T lymphocytes (CTL). The system used non-specific stimulation with phorbyl ester and calcium ionophore, maintenance of growth over the first 6 days of culture with interleukin (IL)-2 and interferon-gamma, and maintenance of growth and differentiation over the last 2 days of culture with IL-2 and IL-6. Under these defined conditions around 50% of all CD4- 8+ T cells developed into CTL clones that were specific in their lytic activity. In contrast, a culture system maintained by irradiated filler cells showed non-specific lysis of both YAC-1 type natural killer targets and of P815 type targets, while a culture system maintained by IL-2 and a crude growth factor preparation showed non-specific lysis of natural killer targets but not of P815. The defined lymphokine culture system was suitable for determining the specificity repertoire of primary CTLp. Using this system, the frequency of reactivity with allogenic tumor targets was found to be approximately one CTLp in 30 for several mouse strain/target cell combinations.

Animals↗
PubMed1991

Lymphokine requirements for the development of specific cytotoxic T cells from single precursors.

A high cloning efficiency, filler cell-free culture system was developed for the growth of single murine cytotoxic T lymphocyte precursors (CTLp) and their differentiation into cytotoxic T lymphocytes (CTL). The system used nonspecific stimulation with phorbol ester and calcium ionophore in the presence of recombinant lymphokines. The optimal lymphokine combination was interleukin 2 throughout, together with interferon-gamma during the first 6 days and interleukin 6 during the last 2 days of culture. Under these conditions half of all CD4-CD8+ T cells became CTL clones. The CTL were CD4-CD8+CD3+ TcR alpha/beta+ and were derived from CD4-CD8+Pgp-1- precursors.

Animals↗
PubMed1990

Amplification of the c-erb B-2 oncogene and prognosis of breast adenocarcinoma.

Fifty patients with typical infiltrating ductal adenocarcinoma of the breast were studied for amplification of the c-erb B-2 (neu/HER-2) oncogene within the tumor DNA. Amplification, ranging from 4 to greater than 50 copies per cell, was observed in 17 (34%) of the samples. The presence of c-erb B-2 gene amplification was not significantly correlated with patient survival, metastases, recurrence, or overall histologic grade. However, amplification was significantly associated with increased mitotic activity. Also, amplification of c-erb B-2 showed a significantly negative association with both progesterone and estrogen receptor presence. Progesterone receptor presence correlated significantly with survival.

Adult↗
PubMed1989

Reinfection of virus free mice with mouse mammary tumour virus.

BR6/Icrf mice carrying a milk-transmitted mammary tumour virus (MMTV) develop tumours after several pregnancies. If the mice are freed from MMTV, no tumours develop. In the experiments described in this paper, MMTV was reintroduced into MMTV-free mice by foster nursing, which was least effective if the pups were exposed to the virus only during the first week of life. Exposure for even a short time after that age led to a tumour incidence similar to that found in normally infected mice. Reinfection was also achieved by injection of MMTV-containing milk into weanling or pregnant mice, and was then transmitted naturally to the next generation.

Aging↗
PubMed1989

IgD production and other lymphocyte functions in HIV infection: immaturity and activation of B cells at different clinical stages.

T and B cell function, in particular IgD production in vitro, were studied across the spectrum of HIV infection in homosexual men and compared with seronegative homosexual and heterosexual male controls. Proliferation to phytohaemagglutinin (PHA) was reduced most strikingly in symptomatic HIV infection; it was also impaired in HIV seronegative homosexual men and there was no difference between these and asymptomatic HIV seropositives or those with persistent generalized lymphadenopathy (PGL). Spontaneous IgG and IgM production were increased in patients with PGL and Kaposi's sarcoma; pokeweed mitogen (PWM)-induced production of IgG and IgM was reduced in all HIV infected subjects. Spontaneous production of IgD was highest in asymptomatic HIV infection, with raised values also seen in PGL and AIDS with opportunist infection; IgD production was suppressed by PWM in the same groups. These data indicate an increase in circulating immature B cells. Markers of B cell immaturity and polyclonal activation are apparent to differing degrees at different stages of HIV infection.

AIDS-Related Complex↗
PubMed1988

Silicone lymphadenopathy in a long distance runner: complication of a silastic prosthesis.

A 33-year-old male runner, who had undergone a Swanson silastic prosthetic implant for degenerative joint disease of the first metatarsal head and proximal phalanx of the right great toe, presented with unilateral inguinal lymphadenopathy. Biopsy revealed confluent, non-caseating granulomas containing silastic material. Silicone lymphadenopathy is unusual and most frequently presents as axillary adenopathy in patients with rheumatoid arthritis as a sequelae of prosthetic surgery. This case is clinically distinctive for its site of presentation in a healthy athlete and is histologically remarkable for the marked granulomatous response to the silastic elastomers.

Adult↗