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Biomedical subjects

J B Matthews

Publications and source records attributed to J B Matthews.

At least 145 records · Page 8Linked to original sources
PubMed1993

The effects of variation of cryopreservation protocols on the immunogenicity of allogeneic skin grafts.

The use of allografts to effect wound closure on full thickness skin injuries is limited by unpredictable graft rejection times. If the period of graft take could be extended, the use of allografts would reduce the morbidity and mortality associated with these wounds. This study evaluated the effects of variation in the cryopreservation protocol on the viability and immunogenicity of skin using a murine model system. Immunogenicity was assessed by the stimulatory activity of C3H (H-2K) skin-derived epidermal cells (EC) in primary one-way EC/lymphocyte reactions with BALB/c (H-2d) and CBA (H-2K) responder lymphocytes. Viability was determined by measuring tetrazolium reductase activity. The following cryopreservation protocols were assessed: freezing at 1, 30, 64, and > 100 degrees C/min in 10 and 15% (v/v) Me2SO and freezing at 30 degrees C/min in 5 to 20% (v/v) Me2SO or glycerol. A cryopreservation protocol of 30 degrees C/min in 15% (v/v) Me2SO proved optimal for murine skin allograft storage and immunomodulation. The viability of skin treated by this protocol was maintained (78% of fresh skin viability, no significant difference analysis of variance). The stimulatory capacity of treated EC for H-2K and H-2d lymphocytes was 5 +/- 4 and 5 +/- 9% (+/- 95% confidence limits) of fresh EC (100%) activity. Langerhans cell numbers in epidermal sheets and EC suspensions did not correlate with the stimulatory capacity of fresh and treated EC for allogeneic lymphocytes. A functional impairment of Langerhans cell immunostimulatory capacity was implied.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Expression of epidermal growth factor receptors by odontogenic jaw cysts.

The expression of epidermal growth factor receptor (EGFr) by odontogenic epithelium was studied in odontogenic cysts (n = 35), ameloblastoma (n = 6), and periapical granulomas containing proliferating epithelial rests of Malassez (n = 7) using a panel of monoclonal antibodies to EGFr (clone E30, F4 and C11) known to react with formalin-fixed, paraffin-embedded sections. Odontogenic epithelium in all specimens demonstrated immunoreactivity with all three antibodies. Clone E30 consistently gave the most intense, membrane located staining pattern of the three antibodies tested. Generally, staining of epithelial cells progressively diminished with movement away from the basal cell layers toward the most superficial layers of cystic lining or centre of epithelial rests and tumour islands. Developmental odontogenic cysts (odontogenic keratocysts, n = 13; dentigerous cysts, n = 11) and ameloblastoma (follicular type, n = 5; unicystic type, n = 1) expressed a higher level of EGFr staining than inflammatory cysts (radicular cysts, n = 11) and the proliferating epithelial rests in periapical granulomas. However, foci of weak EGFr staining of odontogenic keratocyst lining, similar to that seen in radicular cysts, were found in areas associated with inflammation. In addition, epithelial rests not associated with inflammatory cell infiltrates exhibited stronger reactivity for EGFr than proliferating rests within periapical granulomas. These results indicate that the level of EGFr expression by odontogenic cysts and rests is related to the presence of inflammation within adjacent connective tissue and that there is no detectable difference in receptor expression between developmental cysts and ameloblastoma.

ErbB Receptors↗
PubMed1993

Assessment of thermal damage in precooled CO2 laser wounds using biological markers.

Precooling of the tissues was investigated as a possible means of reducing the thermal damage during CO2 laser surgery of the oral mucosa. Standard wounds 5 mm long were created with the CO2 laser, with and without precooling, or the scalpel on the dorsum of tongues. Tissue damage was evaluated by studying changes in mast cells and in the activity of lactate (LDH) and succinate (SDH) dehydrogenase. Cooled unoperated tongues acted as controls. The area of thermal damage, indicated by loss of SDH activity, was significantly smaller in precooled tissues (p < 0.001). Although a similar pattern was detected using LDH, the difference was not significant. At both 0 and 6 h normal mast cell numbers were significantly different between groups (p < 0.02). Furthermore, at 0 time, there were significant differences in the numbers of degranulated mast cells between surgical treatment groups (p = 0.001), although not at 6 h. Total numbers of mast cells (normal and degranulated) did not differ between treatment groups or between 0 and 6 h sampling times. Positive significant correlations were observed between the cross-sectional areas and widths of non-reactive succinate and lactate dehydrogenase and the number of degranulated mast cells around the laser wounds. Analysis of the data demonstrated that (i) uncooled laser wounds but not precooled laser wounds were associated significantly with greater levels of immediate mast cell degranulation than scalpel wounds (p = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Relationship of tobacco/alcohol use to p53 expression in patients with lingual squamous cell carcinomas.

This study examined p53 expression immunocytochemically in 40 lingual squamous cell carcinomas from Dutch patients with known histories of smoking and/or drinking alcohol. 30% of neoplasms showed positive p53 reactivity, suggesting increased levels of p53 protein. No alcohol or tobacco risk factors were evident in 33.3% (4/12) of p53-positive neoplasms whereas only 7.1% (2/28) of p53-negative neoplasms showed an absence of these risk factors. 25% (3/12) of p53-positive neoplasms and 71.4% (20/28) of p53-negative neoplasms were found in patients who had been exposed to both alcohol and tobacco. A similar negative association with p53 reactivity was also found when either tobacco or alcohol were used in isolation. The results contrast with previous observations in head/neck and oral carcinomas and indicate that the association of alcohol/tobacco and p53 expression remains open to question.

Alcohol Drinking↗
PubMed1993

The effect of hypoxia on cytotoxicity, accumulation and DNA binding of cisplatin in Chinese hamster ovary cells.

The literature contains conflicting evidence regarding the hypoxic toxicity of cisplatin. We have found that in Chinese hamster ovary cells, cisplatin was up to 2.6 times more effective at reducing survival to 2% in hypoxic, compared with aerobic cells. Furthermore, using atomic absorption spectroscopy, it was determined that cells treated in hypoxia showed consistently higher accumulation (up to 1.5 times) and DNA binding (up to 1.7 times) than aerobic cells. Hypoxic cells also showed greater toxicity per platinum-DNA adduct than those treated in air, suggesting that increased binding of the drug, alone, cannot account for its increased hypoxic cytotoxicity. We suggest that the hypoxia selectivity of cisplatin involves several different mechanisms and possible explanations for these results are discussed.

Aerobiosis↗
PubMed1993

Plasma cell populations in labial salivary glands from patients with and without Sjögren's syndrome.

Plasma cells expressing IgG, IgA and IgM were quantified in labial salivary glands from patients with Sjögren's syndrome (n = 25) and compared with glands from patients with a variety of systemic diseases (n = 32) and normal individuals (n = 15). Based on qualitative and quantitative analysis, glands from the systemic disease group were divided into normal histology (n = 24) and non-specific inflammation (n = 8) groups. There were no significant differences in cell densities or Ig class proportions between histologically normal glands from patients and those from normal volunteers. Total immunocyte densities were significantly increased in sialadenitis (P < 0.025) and Sjögren's syndrome (P < 0.001) compared with normal histology glands. In both the sialadenitis and Sjögren's syndrome groups there were significant increases in IgG and IgM cell densities (IgG, P < 0.006; IgM, P < 0.001) and proportions (IgG, P < 0.05; IgM, P < 0.001). There were no significant differences in immunocyte densities or proportions between the sialadenitis and Sjögren's syndrome groups except for a lower percentage proportion of IgA cells in the latter (P < 0.038). In all groups the total and individual Ig-class cell densities showed significant positive correlations with extent of leucocyte infiltration (P < 0.01) and negative correlations between IgA and IgG and/or IgM cell proportions. Analysis of the plasma cell data alone and in combination with quantifiable histological parameters failed to yield specific or sensitive diagnostic information. The results suggest that changes in glandular plasma cell populations in Sjögren's syndrome are non-specific.

Adult↗
PubMed1993

A new ultrasensitive chemiluminescent assay for the site-specific quantification of alkaline phosphatase in gingival crevicular fluid.

The search for markers of periodontal disease activity and progression has accelerated over the last decade, in an effort to replace existing subjective clinical measures of periodontal health status. Research is being aimed at establishing more objective and quantitative methodology, capable of rapid diagnosis prior to the appearance of clinical signs of destructive disease. Such tests need to be sensitive enough to evaluate individual periodontal sites in health as well as disease states. We report the development of a new chemiluminescent assay for the enzyme alkaline phosphatase, that is capable of quantifying the enzyme in sub-microliter volumes of gingival crevicular fluid and serum. The technique will measure alkaline phosphatase (ALP) whilst immobilised on paper strips, without the need for an elution stage. It is simple, versatile and amenable to chair-side use. We discuss in detail the assay procedure and have examined levels of ALP in 11 adult volunteers with clinically healthy periodontal tissues. The mean ALP concentration was 2135 IU/L for GCF and 183 IU/L for serum, a 12-fold difference. There also appeared to be an "oral pattern" of enzyme distribution in healthy periodontal sites, with levels being higher in the anterior region of the mouth and highest in the lower anterior region.

Adamantane↗
PubMed1993

Phorbol ester sequentially downregulates cAMP-regulated basolateral and apical Cl- transport pathways in T84 cells.

The effect of phorbol esters on adenosine 3',5'-cyclic monophosphate (cAMP)-regulated epithelial Cl- transport was studied in T84 cells, a human colonic cell line that serves as a model for electrogenic Cl- secretion. Preincubation of T84 cell monolayers with phorbol 12-myristate 13-acetate (PMA) caused a time- and dose-dependent inhibition of the net transepithelial secretory response to 10 microM forskolin (half-maximal inhibition at a concentration of approximately 10 nM PMA and a time of 45 min). Similar inhibition was observed with phorbol 12,13-dibutyrate but not the inactive phorbol ester phorbol 12,13-diacetate. Na(+)-K(+)-2Cl- cotransporter activity, assessed by bumetanide-sensitive 86Rb+ uptake, and K+ conductance, assessed by 86Rb+ efflux, were both found to be markedly reduced by PMA with a time course that paralleled the loss of the cAMP-regulated Cl- secretory response. One- and four-hour treatment of T84 cells with 100 nM PMA caused a sustained increase in the membrane-bound fraction of protein kinase C (PKC) but a decrease in total cellular PKC. Although, at these time points, the Na(+)-K(+)-2Cl- cotransporter and K+ efflux pathways were markedly inhibited (associated with inhibition of the forskolin-stimulated transepithelial Cl- secretory response), the activity of the cAMP-regulated Cl- efflux pathway, assessed by 125I-labeled efflux, remained unaffected. With prolonged exposure to PMA (up to 10), the cAMP-regulated Cl- efflux pathway was also eventually inhibited, and transepithelial electrical resistance progressively declined.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological Transport↗
PubMed1993

Na(+)-K(+)-2Cl- cotransport and Cl- secretion evoked by heat-stable enterotoxin is microfilament dependent in T84 cells.

We previously reported that adenosine 3',5'-cyclic monophosphate-mediated stimulation of Cl- secretion in the human intestinal epithelial cell line T84 is accompanied by significant remodeling of F-actin and that both the secretory and cytoskeletal responses may be inhibited by phalloidin derivatives, agents that polymerize actin and prevent dynamic reorganization of microfilaments. In contrast, the carbachol-elicited Cl- secretory response (Ca2+ mediated) was not attenuated by phalloidin (J. Clin. Invest. 87: 1903-1909, 1991). In the present study, we examine the effect of phalloidin on the Cl- secretory response elicited by the heat-stable enterotoxin of Escherichia coli (STa), which induces elevations in intracellular guanosine 3',5'-cyclic monophosphate. We find that apical administration of 1 microM STa results in a regionally restricted redistribution of F-actin confined to the basal pole of the cells. In monolayers pretreated with phalloidin, the Cl- secretory response to STa was inhibited by > 60%. Sequential treatment of phalloidin-loaded monolayers with STa followed by carbachol resulted in a synergistic secretory response that was not different from control (unloaded) monolayers. Examination of efflux/uptake through specific membrane transport pathways involved in STa-stimulated Cl- secretion indicated normal activation of apical Cl- and basolateral K+ channels under phalloidin-loaded conditions. The ability of STa-treated monolayers to pump Na+ in an absorptive direction was also unaffected by phalloidin. der phalloidin-loaded conditions, STa-stimulated Na(+)-K(+)-2Cl- cotransporter activity was reduced by approximately 60%, sufficient to account for the observed inhibition of net Cl- secretory response.(ABSTRACT TRUNCATED AT 250 WORDS)

Actin Cytoskeleton↗
PubMed1992

The myeloid leukemia cell line HL-60 produces a factor that induces chloride secretion in cultured epithelial cells.

When activated, polymorphonuclear leukocytes (PMNs) produce a small soluble factor, termed neutrophil-derived secretagogue (NDS), that elicits electrogenic Cl- secretion--the transport event responsible for hydration of mucosal surfaces. Work toward purification of this factor has been hampered by variability in activity of PMN-derived NDS. Using a human-derived intestinal epithelial cell line (T84) that serves as a model for studies of the regulation of electrogenic Cl- secretion, we find that the human promyelocytic leukemia cell line HL-60 secrets a factor with NDS-like activity. Buffer conditioned by HL-60 cells (10(7) cells/ml for 1 h), when applied to T84 monolayers grown on permeable supports and analyzed by routine electrophysiological techniques, elicited a short-circuit current (Isc) of 11.7 +/- 1.02 microA/cm2. This short-circuit current was sensitive to bumetanide, an inhibitor of the basolateral Na-K-2Cl cotransporter, and was dependent on the presence of chloride in the assay buffers. Such data indicate that buffer conditioned by HL-60 cells stimulates electrogenic Cl- secretion. Like NDS, the active factor in HL-60-conditioned buffer has a nominal molecular weight of less than 500 and was increased by activation of cells with phorbol ester. 125I and 86Rb efflux assays confirmed that the secretagogue released by stimulated HL-60 cells, similar to PMN-derived NDS, preferentially stimulates opening of Cl- rather than K+ channels in T84 cells. Lastly, release of NDS-like bioactivity increases when HL-60 cells are differentiated toward granulocytes compared to cells differentiated toward monocytes.

Cells, Cultured↗
PubMed1992

Epithelial expression of major histocompatibility complex (MHC) antigens in normal rat salivary and lacrimal glands.

The presence and distribution of MHC class I and class II antigens within these glands of Wistar and Lewis rats was studied using monoclonal antibodies and an indirect immunoperoxidase technique. In rats of both strains and sexes, MHC class 1 antigens were expressed by ductal epithelium in addition to vascular endothelium and other connective tissue elements. Except for a small proportion of secretory cells within lacrimal glands, acini were uniformly negative for class I antigen. MHC class II immune response-associated (Ia) antigens were expressed by stromal dendritic cells in all glands. Glandular expression of Ia was limited to submandibular glands of the two strains. In Lewis rats, staining was detected in some striated and collecting ducts, whereas positive glandular reactivity in Wistar rats was predominantly within the granular-cell tubules. Quantitative histomorphometric studies of Wistar submandibular glands, taken from 2.5-60-week-old male and female animals, demonstrated a close relationship between the extent of glandular Ia reactivity and postnatal granular-cell tubule development. These results indicate that whilst constitutive expression of Ia is a feature of rat submandibular epithelium, the glandular components involved are strain dependent.

Animals↗
PubMed1992

Hypophosphatasia: a family study involving a case diagnosed from gingival crevicular fluid.

Hypophosphatasia is an inherited disorder characterized by defective mineralization of the skeletal and dental structures of the body and deficient liver/bone/kidney alkaline phosphatase (L/B/K ALP) activity. There has been a tremendous advance in our knowledge of this condition over the last decade due to the advent of highly specific DNA probes and novel microanalytic techniques. The purpose of this paper is threefold: to review the dental aspects of current literature about this rare condition; to present a case (and family study) that was diagnosed in a 5-yr-old boy from 0.14 microliters of gingival crevicular fluid, using a new ultrasensitive chemiluminescent assay for the enzyme alkaline phosphatase; and to provide strong evidence for an autosomal dominant mode of inheritance.

Adamantane↗
PubMed1992

Microfilament-dependent activation of Na+/K+/2Cl- cotransport by cAMP in intestinal epithelial monolayers.

cAMP-mediated stimulation of Cl- secretion in the human intestinal cell line T84 is accompanied by significant remodeling of F-actin, and both the secretory and cytoskeletal responses may be largely ablated by previous cell loading with phalloidin derivatives, reagents that prevent dynamic reordering of microfilaments (1991. J. Clin. Invest. 87:1903-1909). In this study, we examined the effect of phalloidin loading on the cAMP-elicited activity of the individual membrane-associated transport proteins involved in electrogenic Cl- secretion. Efflux of 125I and 86Rb was used to assay forskolin-stimulated Cl- and K+ conductances, respectively, and no inhibitory effect of phalloidin could be detected. Na+/K(+)-ATPase pump activity, assessed as bumetanide-insensitive 86Rb uptake and the ability of monolayers to generate a Na+ absorptive current in response to apical addition of a Na+ ionophore, was not different between control and phalloidin-loaded monolayers. Forskolin was found to stimulate Na+/K+/2Cl- cotransport (bumetanide-sensitive 86Rb uptake) in time-dependent fashion. In the absence of any agonist, cotransporter activity was markedly decreased in phalloidin-loaded monolayers. Furthermore, under phalloidin-loaded conditions, the forskolin-elicited increase in bumetanide-sensitive 86Rb uptake was markedly attenuated. These findings suggest that cAMP-induced activity of Cl- channels, K+ channels, and the Na+/K(+)-ATPase are not influenced by F-actin stabilization. However, cAMP-induced activation of the Na+/K+/2Cl- cotransporter appears to be microfilament-dependent, and ablation of this event is likely to account for the inhibition of cAMP-elicited Cl- secretion seen in the phalloidin-loaded state. Such findings suggest that Na+/K+/2Cl- cotransporter is functionally linked to the cytoskeleton and is a regulated site of cAMP-elicited electrogenic Cl- secretion.

Actin Cytoskeleton↗
PubMed1991

Combined surgical and interventional radiological approach for complex benign biliary tract obstruction.

In patients with complicated high benign biliary strictures surgical technique alone cannot exclude the possibility of recurrent problems, and hepatic atrophy/hypertrophy, portal hypertension and intrahepatic stones may all complicate surgical management. A multidisciplinary approach to these complex cases, which minimizes the need for repeated surgical interventions, has been pursued. Roux-en-Y hepaticojejunostomy was performed and an extended limb of the jejunum brought to the abdominal wall to allow access for later radiological intervention. Over a 30-month period 58 biliary-enteric anastomoses for benign disease were performed. Seventeen of these 58 patients were managed using the combined approach. Ten of these 17 patients had complex postcholecystectomy strictures and seven had strictures resulting from inflammatory disease, hepatic resection or congenital problems. A new classification of results of management of bile duct strictures is proposed. Seven patients were classified as 'excellent', six 'good', two 'fair' and two 'poor'. Results were obtained at a mean follow-up of 16 months and it seems likely that in some patients major surgical reinterventions were avoided.

Adult↗
PubMed1991

Detection of Epstein-Barr virus antigens and DNA in major and minor salivary glands using immunocytochemistry and polymerase chain reaction: possible relationship with Sjogren's syndrome.

This study has investigated the presence of Epstein-Barr virus (EBV) in parotid (n = 12), submandibular (n = 15), and minor salivary glands (n = 25) using immunohistochemical methods for detection of EBV-encoded antigens and the polymerase chain reaction (PCR) for detection of viral DNA. Major salivary glands were from patients without connective tissue disease. Labial glands were from patients with primary Sjogren's syndrome (n = 10), rheumatoid arthritis (n = 8), or from normal individuals (n = 7). None of the glands exhibited specific reactivity for lytic (EA-D, EA-R, VCA) or latent (EBNA-2, LMP) viral antigens. Antibodies to EA-D, when used at 20-50 times their optimal concentration, gave lumenal staining of ducts and acini of all the specimens tested (n = 14), irrespective of the presence (n = 8) or absence (n = 6) of EBV-DNA by PCR. Ductal immunoreactivity for the EBV/C3d (CR2, CD21) receptor was found in 40 per cent of specimens. PCR detected EBV-DNA in 64 per cent submandibular, 46 per cent parotid, and 80 per cent of minor glands. There were no significant differences in the detection of EBV-DNA between specimen/patient groups. Only type A EBV was detected by strain typing PCR. These results indicate that EBV (type A), undetected immunocytochemically, is commonly present at low copy numbers within salivary glands irrespective of a clinical diagnosis of Sjogren's syndrome.

Adult↗
PubMed1991

MHC antigen expression in human oral squamous carcinoma cell lines.

This study quantified the constitutive and interferon-gamma (IFN-gamma) stimulated expression of MHC class I (HLA-ABC and beta 2 microglobulin) and class II antigens (HLA-DR, -DP, -DQ) on normal and malignant oral keratinocytes using radioimmunoassay and immunocytochemical techniques. Normal keratinocytes and three of four malignant cell lines (H103, H157, H314) expressed MHC class I antigens constitutively; IFN-gamma increased MHC class I expression with significant changes in normals, H157 and H314. Normal keratinocytes expressed significantly more constitutive MHC class I antigens than H103 and H157 and significantly more IFN-gamma stimulated MHC class I antigens than H103, H157 and H314. MHC class II antigens predominantly were not expressed constitutively on normals, H103 and H157 but, in H314, HLA-DR, -DP and -DQ antigens were demonstrated on 35, 11 and 5 per cent of cells, respectively, and resulted in a non-coordinated pattern of expression (HLA-DR greater than -DP = -DQ). IFN-gamma induced HLA-DR on normals, H103 and H157, whilst HLA-DP and -DQ remained undetectable. In H314, IFN-gamma enhanced HLA-DR, -DP and -DQ (significant increase of HLA-DQ) but the interrelationship between these antigens was maintained (HLA-DR greater than -DP = -DQ). Normal keratinocytes expressed significantly more IFN-gamma stimulated HLA-DR than H103 and H157 but significantly less HLA-DR than H314 under similar experimental conditions. One oral malignant cell line (H191) did not express MHC class I and MHC class II antigens either constitutively or in response to IFN-gamma. The results demonstrate aberrant patterns of MHC expression (absence, enhanced, diminished) in the different malignant oral keratinocyte cell lines.

Carcinoma, Squamous Cell↗
PubMed1991

Primed and naive helper T cells in labial glands from patients with Sjogren's syndrome.

This study has investigated the presence and distribution of B cells, T cells and T-cell subsets within labial glands of patients with primary Sjogren's syndrome (n = 9) and secondary Sjogren's syndrome associated with rheumatoid arthritis (n = 8) using a sequential double immunoperoxidase technique and true colour image analysis. The composition of the inflammatory infiltrates was similar in glands from both patient groups. B cells were normally present within large foci with few detected in diffuse infiltrates such that the ratio of T:B cells in foci (2.4:1) was significantly lower than in diffuse infiltrates (7.3:1; P less than 0.001). In all infiltrates helper T cells (CD8-, CD3+) predominated over suppressor/cytotoxic cells (CD8+, CD3+; 2.7:1). Analysis of primed (CD45RA-, CD45RO+) and naive (CD45RA+, CD45RO-) CD8- T cells showed that the ratio of the primed to naive subset was significantly higher in focal (4.2:1) compared to diffuse (1.5:1; P less than 0.001) areas of lymphoid infiltration. These results indicate that the focal lymphocytic infiltrates characteristic of Sjogren's syndrome contain B cells associated with a T-cell population consisting predominantly of primed CD8- helper T cells. This latter population may be responsible for upregulating glandular B-cell activity in Sjogren's syndrome.

Antigens, CD↗