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Biomedical subjects

D B Jones

Publications and source records attributed to D B Jones.

At least 91 records · Page 5Linked to original sources
PubMed1997

Optimisation of the polymerase chain reaction.

The polymerase chain reaction (PCR) is a method by which specific sequences of DNA can be copied many times, allowing detailed molecular studies to be performed on as little as a single cell. Numerous and diverse applications of PCR are being developed across all disciplines of diagnostic pathology and research, and no single protocol is appropriate for all situations. Optimising PCR requires a delicate balance between the amplification of specific products and avoiding the production of non-specific products. Each step, from DNA template extraction to cycling times and temperatures, needs to be considered carefully. The aim of this study is to assess which parameters influence DNA amplification efficiency and specificity. The parameters evaluated are the denaturation, annealing and extension temperatures, the number of cycles performed, and the primer, magnesium chloride, dNTP, Taq DNA polymerase and DNA template concentrations. The important parameters for efficient, specific amplification were denaturation time and temperature, stringent annealing temperatures and magnesium chloride concentration. The importance of DNA concentration was found to depend upon the source from which the DNA was extracted.

DNA Primers↗
PubMed1996

Splenic marginal zone expansion in B-cell lymphomas of gastrointestinal mucosa-associated lymphoid tissue (MALT) is reactive and does not represent homing of neoplastic lymphocytes.

It has been suggested that lymphocytes of mucosa-associated lymphoid tissue (MALT) arise from marginal zone cells and that MALT-derived lymphomas may spread to other extra-nodal sites by homing to marginal zones in different tissues. Marginal zone expansion has been observed in spleens removed during surgery for gastrointestinal MALT lymphoma, which was sufficiently extreme in some cases to suggest neoplastic involvement. To investigate this phenomenon, polymerase chain reaction (PCR) amplification of immunoglobulin heavy chain gene fragments was performed to demonstrate B-cell clonality in gastrointestinal MALT lymphomas and spleens from 11 patients. Monoclonal PCR products were obtained from 9 of the 11 gastrointestinal tumours but from none of the accompanying spleens. One additional spleen, for which the accompanying gastric lymphoma tissue was unavailable for review, yielded a monoclonal product. However, obvious lymphoma deposits were present in this specimen, in addition to marginal zone enlargement. It is concluded that splenic marginal zone expansion accompanying gastrointestinal MALT lymphoma is correctly interpreted as being reactive. Splenic involvement by MALT lymphoma is uncommon and does not show preferential colonization of the marginal zone to suggest homing of MALT-derived cells to this site.

B-Lymphocytes↗
PubMed1996

A study of accessory cells in the acquired lymphoid tissue of helicobacter gastritis.

This paper presents a description of the patterns of distribution of accessory cells in helicobacter gastritis and low-grade gastric MALT lymphomas. The use of gastric resection specimens afforded abundant, well-orientated lymphoid tissue. Fifteen cases were selected from patients with MALT lymphomas, three with gastritis alone, and six histologically normal controls. A panel of antibodies working in paraffin-embedded tissue, identifying differing accessory cells, was used. These comprised antibodies to HLA class II (WR18), acid cysteine proteinase inhibitor (ACPI), CD68 (PGM1), Factor XIIIa, S100 protein, CD23 (BU38), CD106 (V-CAM1), CD55 (BRIC 128), and CD21 (1F8). CD68-positive macrophages in the gastritis cases were abundant in the superficial mucosa. Factor XIIIa also identified dendritic cells at deeper sites but these were absent from both the acquired and the neoplastic lymphoid tissue. Antibodies to both S100 protein and ACPI stained dendritic cells localized to areas within and adjacent to the lymphoid tissue only. S100 protein-positive cells were concentrated in close contact with glandular epithelium immediately above the germinal centres, while ACPI-positive dendritic cells were identified, especially around the more blastic reactive follicles, in the intervening space between the germinal centres and the overlying epithelium. Similar patterns of organization were also seen in the areas of mucosal lymphoma. The follicular dendritic markers revealed overlapping but distinct sub-populations within the germinal centres which appeared to alter depending on the activity of the germinal centres. While both ACPI and CD55 stained the germinal centre dendritic reticulum cell networks only, CD21 and CD106 also stained the mantle dendritic cells. The proportion staining with CD23, which stains dendritic reticulum cells within the centrocyte-rich areas of the germinal centres only, was greatest in the more quiescent germinal centres. Similar patterns of staining were also seen in germinal centres within the gastric MALT lymphomas. It is proposed that the sub-populations of dendritic cells staining with S100 protein and ACPI may facilitate helicobacter antigen delivery to the germinal centres. The follicular dendritic cells then promote a sustained B-cell response to the luminal pathogen.

Antigen Presentation↗
PubMed1996

Contribution of monocyte/macrophage differentiation to the stromal layer in human long-term bone marrow cultures.

The stroma of bone marrow is a poorly understood tissue which is believed to have important roles in haemopoietic stem cell maintenance and differentiation. We have undertaken immunohistochemical studies of bone marrow stroma in human long-term bone marrow cultures (hLTBMC) and biopsy specimens in order to characterise the cell and matrix components present. We have found two morphological variants of macrophages to be present consistently in hLTBMC stroma, adherent to a substratum of myofibroblastic cells. Large round macrophages appear to actively phagocytic and are formed in hLTBMC regardless of successful establishment of a myofibroblastic cell layer. Elongated macrophages with dendritic processes appear to be non-phagocytic and form only in the presence of a well-established layer of myofibroblasts. Although the functions of these macrophages are not yet known, they have counterparts within intact human bone marrow and their presence in hLTBMC shows some association with the haemopoietic capacity of the cultures.

Bone Marrow Cells↗
PubMed1996

Heterogeneity of expression of CD68 and other macrophage-associated antigens in human long-term bone marrow culture.

The authors have performed an immunohistochemical study of intact human long-term bone marrow cultures (hLTBMC) grown directly onto glass slides. Between 4 and 12 weeks of growth, such cultures consist of a complex stromal layer supporting foci of haemopoietic cells which undergo granulocytic and monocytic differentiation. As part of a large panel of antibodies employed to characterize monocytes and macrophages within hLTBMC, we included six different anti-CD68 reagents and three antibodies representing a putative new CD group recognizing a macrophage-associated antigen of 130 kDa molecular weight. These gave heterogeneous immunostaining patterns with macrophages and stromal myofibroblastic cells.

Antibodies, Monoclonal↗
PubMed1996

Expression of the human heat shock protein 60 in thyroid, pancreatic, hepatic and adrenal autoimmunity.

Heat shock proteins (hsps) have been proposed to play a role in autoimmune disease. Their highly conserved nature and role as a common antigenic determinant throughout phylogeny has raised the possibility that they may act as cellular targets of an autoimmune response when their expression is altered in stressed tissue cells. Using an antibody to human hsp60 we have demonstrated a wide tissue distribution in normal tissues, including thymus, the degree of staining reflecting the content of mitochondria in the cells, consistent with the known mitochondrial location of this protein. Enhanced staining was also demonstrated in oncocytes (deeply eosinophilic cells which have greatly increased numbers of mitochondria) in both thyroid and adrenal autoimmune disease and also in unrelated conditions where oncocytic change was identified. No enhancement was demonstrated in target cells in organ specific autoimmune diseases where oncocytic change was not seen, for example islet cells in diabetes and bile duct cells in primary biliary cirrhosis. Thus, no alteration of hsp60 expression was demonstrated which was specific to the autoimmune diseases studied.

Adrenal Glands↗
PubMed1996

Proliferative lymphocyte responses to virus antigens homologous to GAD65 in IDDM.

Virus infection has been proposed as an initiating factor in the aetiology of insulin-dependent diabetes mellitus (IDDM). We have examined lymphocyte proliferation to virus proteins which demonstrate sequence similarity to the beta-cell autoantigen glutamic acid decarboxylase (GAD)65. The magnitude and frequency of response to coxsackie B viruses and adenovirus in a T-cell proliferation assay was significantly higher in a group of recently diagnosed IDDM subjects than in non-diabetic control subjects. The frequency of positive response to the coxsackie B viruses was also significantly higher in IDDM subjects expressing the DRB 1*04 major histocompatibility complex (MHC) haplotype than the DRB 1*03 haplotype. There was no evidence that non-aspartate residue at position 57 of DQB 1 genes influenced virus responses in the IDDM group. The coxsackie homology was in amino acids 258-266 and the adenovirus homology was in amino acids 509-524 of GAD65. Both these regions are suspected to be T-cell epitopes in IDDM. These results indicate a disease and MHC class II association between coxsackie B virus infection and IDDM and an association between adenovirus infection and IDDM.

Adenoviridae↗
PubMed1996

Corneal anesthetic abuse and Candida keratitis.

PURPOSE: Topical corneal anesthetic abuse is a self-inflicted injury, causing profound corneal morbidity. Superimposed infection is an important complicating factor. The authors report four patients with confirmed topical anesthetic abuse of the cornea, in whom Candida keratitis developed. METHODS: A retrospective review of the medical records of four patients with confirmed topical corneal anesthetic abuse and fungal keratitis. RESULTS: A 21-year-old woman, two 28-year-old women, and a 35-year-old man were included in the study. All these patients sustained a corneal injury, prompting the chronic use of topical anesthetics (0.5% proparacaine hydrochloride in 3 patients, and 0.5% tetracaine hydrochloride and 0.4% benoxinate hydrochloride in the other). Corneal findings included epithelial defects in all patients, focal infiltrate in one patient, and ring-shaped stromal infiltrate in three patients. Topical anesthetic was discontinued, all patients initially were treated empirically with antibacterial agents, and three patients received topical corticosteroids. Subsequent corneal cultures grew Candida spp, Candida albicans specifically in three patients, and local and systemic antifungal therapy was started. Corneas in two patients re-epithelialized; a conjunctival flap was performed on another patient with a descemetocele; and the remaining patient was lost to follow-up, although repeat fungal cultures yielded no growth. CONCLUSIONS: Corneal superinfection with Candida may occur during topical anesthetic abuse. Therapy includes discontinuation of the anesthetic and institution of antifungal therapy.

Administration, Topical↗
PubMed1996

Development and comparison of transperitoneal and retroperitoneal approaches to laparoscopic-assisted aortofemoral bypass in a porcine model.

PURPOSE: Transperitoneal and retroperitoneal approaches to video-assisted aortofemoral bypass were developed and compared using gasless laparoscopic techniques in a porcine model. METHODS: Ten pigs were randomized to either a transperitoneal or retroperitoneal approach. Aortic clamp time, total operative time, and complications were recorded. Both operations used an external lift device to maintain the working space. Retroperitoneal operations first used serial balloon inflation to dissect the retroperitoneum. After exposure of the infrarenal aorta, a graft was tunneled under endoscopic visualization. End-to-side aortic and femoral anastomoses were created with conventional instruments through 4 cm incisions. RESULTS: Mean +/- SEM aortic clamp time, operative duration, and graft patency rates were similar for both approaches (difference not significant by unpaired t test). Intraoperative complications related to the use of the laparoscopic technique included injury to the bladder and small bowel (n=2) and occurred only in the transperitoneal group. CONCLUSIONS: The use of a gasless technique allowed direct visualization, standard instrumentation, and conventional anastomotic techniques. The retroperitoneal approach used the peritoneal sac to exclude the bowel, simplifying the aortic dissection. Gasless laparoscopic-assisted aortofemoral bypass can be performed by both transperitoneal and retroperitoneal approaches and holds promise as a minimally invasive treatment for aortoiliac occlusive disease.

Anastomosis, Surgical↗
PubMed1996

Investigation of specimen mislabelling in paraffin-embedded tissue using a rapid, allele-specific, PCR-based HLA class II typing method.

Mislabelling of surgical specimens can seriously affect the accuracy of histopathology reports. We describe two cases in which clinically suspected mislabelling was investigated by polymerase chain reaction (PCR)-based HLA DRB and DQB tissue typing of paraffin biopsy-derived DNA, using sequence specific primers (PCR-SSP HLA typing). In the first case, two patients underwent surgery for breast carcinoma. A subcutaneous lymph node containing metastatic carcinoma was received with the breast specimen from one patient, but was clinically considered more likely to originate from the other patient who underwent breast surgery on the same day. In the second case, histological examination of retained products of conception from a young woman revealed adenocarcinoma, but a repeat curettage specimen consisted of secretory phase endometrium. In case 1, PCR-SSP HLA typing confirmed the clinical suspicion that the subcutaneous lymph node received with tissue from one patient originated from the other patient. This result converted the first patient from lymph node positive breast carcinoma to lymph node negative disease. In case 2, there was no evidence from PCR-SSP HLA typing that the endometrial samples had originated from different patients. PCR-SSP HLA typing requires fewer steps than methods based on PCR amplification followed by oligonucleotide probing (PCR-SSOP HLA typing), and relies on the amplification of shorter sequences of DNA. Therefore, this technique can produce more rapid results than PCR-SSOP HLA typing, and is ideally suited to typing partially degraded DNA derived from formalin-fixed and paraffin-embedded tissue.

Adenocarcinoma↗
PubMed1996

Accessory cells in Crohn's disease of the terminal ileum.

We present a study which describes the immunophenotype and distribution of accessory cells in 13 resections of terminal ileum from patients with Crohn's disease. A panel of antibodies working in paraffin-embedded tissue was employed and these included PGM1 (CD68), S-100 protein, WR18 (HLA class II), factor XIIIa and acid cysteine proteinase inhibitor. This study revealed a heterogeneity of accessory cell populations which was profoundly influenced by local inflammatory and repair mechanisms. Both acid cysteine proteinase activity and S-100 protein positive cells are identified in more actively inflamed areas. The acid cysteine proteinase activity positive dendritic cell population was particularly numerous in ulcer bases. S-100 protein positive dendritic cells had a more limited distribution in close proximity to the epithelium in inflamed but otherwise intact mucosa adjacent to the areas of ulceration. PGM1 revealed normal distribution of macrophages within histologically uninvolved areas and, in addition, also stained granulomas and large numbers of dendritic cells in the inflamed, ulcerated and scarred areas. Factor XIIIa positive dendritic cells were especially numerous in areas of active scarring where they co-localized with PGM1 positive cells. They were largely absent from the more superficial ulcerated areas. HLA class II was strongly expressed on mononuclear inflammatory and dendritic cells. The strength of epithelial staining for HLA class II reflected the intensity of adjacent inflammation, except on ulcer-associated epithelium which consistently showed up-regulation independent of the severity of the inflammatory process. This study shows that localized alterations in the accessory cell distribution in Crohn's disease correlate with different states in the evolution of the inflammatory and repair process of the disease. The more acute lesions are associated with recruitment of acid cysteine proteinase activity and S-100 protein positive dendritic cells while factor XIIIa stained dentritic cells are especially numerous in areas of scarring.

Antigen-Presenting Cells↗
PubMed1996

Accessory cells in physiological lymphoid tissue from the intestine: an immunohistochemical study.

We report a study of the organization of accessory cell populations, in normal mucosal lymphoid tissue from small intestine (8 cases), large intestine (6) and appendix (9) using a panel of monoclonal antibodies and polyclonal antisera in paraffin-embedded tissue. Two populations were identified in dome areas, one positive for acid cysteine proteinase inhibitor and HLA class II (WR18) only and the second positive for S-100 protein, CD68, and WR18 and negative for acid cysteine proteinase inhibitor and factor XIIIa. Superficial colonic mucosal and small intestinal villous tip macrophages stained positively with CD68 and WR18 only, while deeper cryptal and submucosal populations exhibited additional positivity for factor XIIIa, but both populations were negative for acid cysteine proteinase inhibitor and S-100 protein. Germinal centre macrophages were positive for CD68, WR18 and acid cysteine proteinase inhibitor and negative for factor XIIIa, and S-100 protein. T zone dendritic cells included a population which stained positively for S-100 protien, WR18 and were negative for factor XIIIa, CD68 and acid cysteine proteinase inhibitor, an immunophenotype typical of interdigitating dendritic reticulum cells. This distribution of phenotypically identifiable accessory cell subpopulations was apparent at all three sites examined. We suggest that the specialized subpopulations of dendritic cells staining for S-100 protein and for acid cysteine proteinase inhibitor which are restricted to the dome areas, may have a potential role in the transfer of antigen across the epithelium to the germinal centres, while factor XIIIa appears to identify a tissue macrophage population with a potential role in stromal modulation distant from direct antigen challenge.

Antigen-Presenting Cells↗
PubMed1996

Case report: acanthosis nigricans in association with primary biliary cirrhosis: resolution after liver transplantation.

A case is described of a 58 year old Caucasian male with primary biliary cirrhosis (PBC) who first presented with acanthosis nigricans of both axillae, skin pigmentation, which was pronounced over the posterior surface of the neck, and generalized pruritus. Following orthotopic liver transplantation for progressive liver disease, the skin pigmentation, pruritus and acanthosis nigricans resolved. It is believed that this is the first reported case of acanthosis nigricans occurring in association with PBC, a phenomenon that resolved after liver transplantation.

Acanthosis Nigricans↗
PubMed1996

Risk factors for herpes simplex virus epithelial keratitis recurring during treatment of stromal keratitis or iridocyclitis. Herpetic Eye Disease Study Group.

AIMS: Possible risk factors were evaluated for herpes simplex virus (HSV) epithelial keratitis in patients with stromal keratouveitis. METHODS: The study population included 260 patients who had active stromal keratitis and/or iridocyclitis without epithelial disease and who were enrolled in one of three clinical trials of the Herpetic Eye Disease Study. Study treatment involved a 10 week course of topical placebo, topical prednisolone phosphate, or topical prednisolone phosphate with oral acyclovir. All groups received topical trifluridine four times daily for 3 weeks then twice daily for another 7 weeks. Patients were examined for HSV epithelial keratitis for 16 weeks. RESULTS: Dendritic or geographic epithelial keratitis occurred in 12 (4.6%) study patients. Adverse effects attributable to trifluridine prophylaxis were acute allergic blepharoconjunctivitis in 10 (3.8%) study patients and corneal epithelial erosions in 11 (4.2%) study patients. No significant difference in the occurrence of HSV epithelial keratitis was found among the study treatment groups: one (2.0%) of 49 topical placebo treated patients, nine (6.5%) of 138 patients treated with topical corticosteroids without acyclovir, and two (2.7%) of 73 patients treated with topical corticosteroids and oral acyclovir. Univariate exponential models suggested that patients with a history of previous HSV epithelial keratitis and non-white patients were more likely to develop HSV epithelial keratitis during treatment of stromal keratouveitis. CONCLUSION: Individuals with prior HSV epithelial keratitis and certain ethnic groups may have a higher rate of recurrent epithelial keratitis during the acute treatment of HSV stromal keratouveitis.

Acyclovir↗
PubMed1996

CD45RO and CD45RA positive cell populations in idiopathic membranous and IgA glomerulopathy.

AIMS: To immunophenotype and quantitate glomerular and interstitial inflammatory cells in cases of idiopathic membranous and IgA glomerulopathy; to correlate cell numbers with aspects of clinical data and renal function. METHODS: Routine indirect immunoperoxidase staining was performed on frozen section renal biopsy specimens for T and B lymphocyte related antigens, macrophages and MHC class II antigens. Double immunohistochemical staining was performed to identify CD45RO+ and CD45RA+ cells. RESULTS: In IgA glomerulopathy correlations were found relating interstitial cell numbers to creatinine concentration at biopsy (CD45RO+ and CD45RA+ cells) and follow up creatinine concentration (CD3+, CD4+, CD8+, CD45RO+, and CD45RA+ cells). Also in IgA glomerulopathy mean arterial pressure at biopsy correlated with interstitial cell numbers and most recent follow up creatinine concentration. There were no correlations between glomerular inflammatory cells and renal function in either disease. Double staining showed that although most glomerular CD45RO+ and CD45RA+ cells were macrophages, positive cells in the interstitium were lymphocytes. The interstitial CD45RO+:RA+ ratio in normal renal biopsy specimens was approximately 5:1; for IgA glomerulopathy it was 1.5 and was 1.0 in idiopathic membranous glomerulopathy. CONCLUSIONS: This study demonstrates that interstitial, and not glomerular, inflammatory cell numbers correlate with renal function in primary glomerular disease and that double staining is necessary to interpret positive immunostaining for antigens located on more than one type of inflammatory cell. Detailed investigation of the interstitial CD45RO+ and CD45RA+ cells may give an insight into the pathogenesis of glomerular disease.

Adolescent↗
PubMed1996

Complications of laparoscopic cholecystectomy.

Video technology allows surgeons to offer patients operations through small incisions. While these minimally invasive techniques have been employed for a wide range of operations for many years, only recently has a laparoscopic cholecystectomy been possible. Compared to the same operation performed via laparotomy, it is deemed the "gold standard." Overall mortality after laparoscopic cholecystectomy ranges from 0-1%, and the rate of major complications is less than 5%. As a group, general surgeons are beyond their initial learning curve for laparoscopic cholecystectomy, but the majority of iatrogenic injuries can be successfully avoided by appreciating the limitations and pitfalls of laparoscopic surgery, and by carefully dissecting the hepatocystic triangle before dividing any structure. Early identification and management of complications will minimize potentially devastating complications of small, unrecognized injuries. Physicians need to accurately advise patients of the proposed advantages and potential problems of laparoscopic cholecystectomy before referring them to a surgeon.

Cause of Death↗
PubMed1996

Expression of CD44 and integrins in bronchial mucosa of normal and mildly asthmatic subjects.

We have investigated the expression of cell surface markers and leucocyte cell adhesion molecules by immunohistochemistry in bronchial biopsies from 10 mild atopic asthmatics and 8 normal, nonatopic subjects. Significantly increased numbers of eosinophils (p<0.01) were evident in the bronchial submucosa of asthmatic subjects. In epithelium there were more CD44+ (p<0.02) and lymphocyte function-associated antigen-1 (LFA-1)+ (p<0.06) leucocytes in asthmatics than in normal subjects. Bronchial epithelial cells stained positively with anti-CD44 monoclonal antibodies (moAb) in both groups; however, when the staining was expressed as percentage of the total basement membrane, a considerable and highly significant increase was observed in the asthmatics (median 80 vs 22%, p=0.003). Few leucocytes were positive for very late activation antigen (VLA)-1, VLA-2 and VLA-4. The moAb for VLA-6 stained the basement membrane of the bronchial epithelium; while intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were constitutively expressed in endothelium. A positive correlation was found between LFA-1+ cells and activated eosinophils (EG2+) in the submucosa (p<0.005; r(s)=0.80). We conclude that even in mild asthma there is evidence of increased expression of cell surface ligands, and suggest that adhesive mechanisms play a role both in cell recruitment and disease activity.

Adult↗