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R C Jordan

Publications and source records attributed to R C Jordan.

18 recordsLinked to original sources
PubMed1996

Porcine malignant hyperthermia: genotype and contractile threshold of immature muscles.

We investigated whether malignant hyperthermia (MH)-related contractile abnormalities, such as lowered contractile threshold, were expressed in MH-susceptible (MHS) immature muscles and myotubes. Muscles from neonatal piglets homozygous for Arg615 (normal) or for Cys615 (MHS) ryanodine receptor alleles, and heterozygotes were used. Intact cell bundles from piglet muscles generally were similar in contractile properties to adult muscles of the same genotype. Thresholds for K contractures in normal, heterozygous, and MHS piglet muscles (40 mmol/L, 25 mmol/L and 15 mmol/L K+, respectively) differed significantly. Cultured myotubes were subjected to a series of square pulses of varying strengths (-50 to +50 mV) and durations (25-300 ms) using whole cell patch-clamp techniques. Threshold for contraction differed significantly among the three genotypes, for example, with 300 msec pulses thresholds were -6.9 +/- 0.9, -12.4 +/- 1.6, and -22.6 +/- 2.6 mV for normal, heterozygous and MHS myotubes, respectively. Thus a significantly lower than normal threshold for contraction was expressed in MHS and heterozygous piglet muscles and myotubes. Further, these developmentally immature preparations are likely to express other differences characteristic of adult MHS muscles, and thus provide suitable preparations for clinically relevant studies of MH-related cellular abnormalities.

Aging↗
PubMed1996

High prevalence of B-cell monoclonality in labial gland biopsies of Japanese Sjögren's syndrome patients.

Patients with Sjögren's syndrome (SS) have an increased risk of developing malignant lymphoma. Although some clinical parameters may herald the imminent onset of lymphoma, few reliable markers are available to predict the progression to a malignant lymphoproliferative disorder. Although there are a number of immunological and serologic features that distinguish SS in Japanese patients, in common with their Western counterparts these patients also have an increased risk of lymphoid neoplasia. Recently we have reported finding a high prevalence (17%) of monoclonal immunoglobulin (Ig) heavy chain gene rearrangements in labial salivary gland (LSG) biopsies of Western SS using the polymerase chain reaction (PCR). In many cases this finding was predictive for the subsequent development of lymphoma. In this study LSG from 50 Japanese SS patients were examined for Ig heavy chain gene monoclonality using PCR to amplify the VDJ region and identified in 7 of 50 (14%) cases. Three patients with monoclonality in the LSG had evidence of lymphoma at extra-salivary gland sites. In one of these the diagnosis of lymphoma was made subsequent to lip biopsy. In the other two lymphoma at extra-salivary gland sites was diagnosed prior to LSG biopsy. The results suggest that the prevalence of Ig heavy chain gene monoclonality in LSG of Japanese SS patients is similar to that in the West, and that neoplastic cells can be identified in LSG as a component of more widely disseminated disease.

Aged↗
PubMed1996

B-cell monoclonality in salivary lymphoepithelial lesions.

It is well recognised that lymphoma may arise in a lymphoepithelial lesion of the salivary glands. Although the histological features of this lesion are well described, it is not clear what proportion contain monoclonal populations of lymphocytes at outset. In this study, 22 routinely processed lymphoepithelial lesions in parotid glands were examined for B-cell monoclonality using the polymerase chain reaction (PCR) to amplify the immunoglobulin heavy chain gene and using in situ hybridisation or immunohistochemistry to detect kappa or lambda light chain restriction. B-cell monoclonality was identified in 17/22 (77.3%) cases using a combination of the three methods. The detection rate for B-cell monoclonality was highest using PCR with 15/22 (68%) cases containing monoclonal immunoglobulin heavy chain gene rearrangements. In a proportion of cases the results of in situ hybridisation and immunohistochemistry were judged to be inadequate and this was probably a reflection of variations in fixation. In 7 patients, sequential biopsies were available from other sites and 6 of these also showed B-cell monoclonality. The results confirm the high prevalence of B-cell monoclonality in lymphoepithelial lesions of the major salivary glands. Furthermore, these results would suggest that PCR is a more reliable technique to identify B-cell monoclonality in routinely processed lymphoepithelial lesions compared to in situ hybridisation and immunohistochemistry.

Adult↗
PubMed1996

Lymphoma in Sjögren's syndrome. From histopathology to molecular pathology.

A number of autoimmune diseases predispose to the development of neoplasia. A particularly well-recognized association is the development of lymphoma in Sjögren's syndrome. Although this risk has been estimated to be 44 times that of the general population, few reliable prognostic indexes exist for individual patients. Recent advances in molecular biology have improved our understanding of Sjögren's syndrome and permitted better characterization of the generalized lymphoproliferation associated with the condition. This article reviews the histopathology of the major and minor salivary gland lesions of Sjögren's syndrome and discusses advances in molecular biology that have permitted more accurate prediction of lymphoma development in this group of patients.

Base Sequence↗
PubMed1995

High frequency of light chain restriction in labial gland biopsies of Sjögren's syndrome detected by in situ hybridization.

A well-recognized complication of Sjögren's syndrome (SS) is the development of malignant lymphoma, with a risk 44 times that of the general population. Although a few clinical signs may indicate the onset of lymphoma, there are few reliable laboratory markers which predict the development of neoplasia. A non-isotopic in situ hybridization technique has been applied to routinely processed labial salivary gland (LSG) biopsies of patients under investigation for SS. Serial section of 70 LSGs were examined for a kappa and gamma immunoglobulin light chain mRNA using digoxigenin-labelled oligonucleotide probes. As controls, 39 biopsies from non-SS-associated sialadenitis were also examined. Sections were analysed using computer-assisted quantification to determine the percentage of kappa-expressing cells in each case. The range of kappa expression in the SS group was 24.1-93.4 percent and in the non-SS group 48.3-75.4 per cent. Light chain restriction was found in 13/70 (18.6 percent) cases from the SS group but in no cases of the control group. Of the SS cases showing restriction, 4/13 (30.7 percent) have subsequently developed extrasalivary gland lymphoma. Two patients not showing light chain restriction in LSG have subsequently developed lymphoma. The positive predictive value of this test to identify patients at risk of lymphoma was 30.7 percent with a detection rate (sensitivity) of 66.7 percent and a false-positive rate of 14.1 per cent(specificity 85.9 percent). This study has identified a high prevalence of light chain restriction in labial gland biopsies of patients with SS and provides objective quantitative criteria to identify those patients at greater risk of lymphoma development.

Adult↗
PubMed1995

Verrucous carcinoma of the mouth.

Verrucous carcinoma is a slow-growing, well differentiated carcinoma that is chiefly exophytic but can invade and destroy oral tissues. It typically presents as an extensive, white, warty lesion of the buccal mucosa or mandibular gingiva, although it also occurs at other sites. Diagnosis can be difficult, with repeat biopsies being needed in some cases. The persistent nature of the condition can make management difficult and the possibility of recurrent disease is high.

Carcinoma, Verrucous↗
PubMed1992

Development of an orofacial model of acute inflammation in the rat.

An appropriate model was created by the paraperiosteal injection of mustard oil (20% allyl isothiocyanate dissolved in mineral oil) into the periarticular temporomandibular tissue of anaesthetized rats. Inflammation was assessed by the plasma extravasation of Evans' blue dye bound to plasma protein. This was confirmed visually and compared spectrophotometrically with the contralateral untreated control site (p less than 0.0005). A time-course study of the effect of mustard oil on Evans' blue extravasation revealed a gradually increasing effect that was maximal at 30 min after administration, with no further increase at 60 min. A dose-response study showed that giving 30 microliters of 20% mustard oil produced the maximal effect, with no further increase from 50 microliters. To confirm induction of inflammation, polymorphonuclear neutrophil infiltration was assessed morphometrically and found to increase in the treated tissue compared with the contralateral untreated control (p less than 0.001).

Acute Disease↗
PubMed1992

Facial neuralgias: a clinical review of 34 cases.

This paper reviewed the clinical features of the facial neuralgias, and described the demographic data for 24 cases of atypical facial neuralgia, seven cases of trigeminal neuralgia, two cases of cluster headache and one of glossopharyngeal neuralgia, which were all referred for investigation and treatment over a three-month period to a teaching hospital dental department.

Adult↗
PubMed1991

Immunohistochemical demonstration of actinically damaged elastic fibers in keratoacanthomas: an aid in diagnosis.

The inclusion of elastic fibers within the epithelium of keratoacanthomas is a phenomenon suggested to be an aid in differentiating this lesion from squamous cell carcinoma. Antilysozyme antibodies have recently been noted to stain actinically damaged elastic fibers but not those from sunprotected skin. In this study, 54 keratoacanthomas and 46 squamous cell carcinomas were stained with a histochemical elastic tissue stain and polyclonal antibody to lysozyme using an immunoperoxidase technique. Elastic fibers were demonstrated in keratoacanthomas (37/54, 68%) significantly more often than squamous cell carcinomas (12/46, 26%) (p less than 0.001) using both techniques. This study confirms that the inclusion of elastic fibers occurs significantly more often in keratoacanthomas than squamous cell carcinomas. These elastic fibers were also actinically damaged, suggesting a role for sun damage in the evolution of keratoacanthoma.

Adult↗
PubMed1991

The oral manifestations of HIV infection.

The spectrum of oral lesions found in the HIV-infected population forms a diverse group of opportunistic conditions, all of which may be seen in non-HIV infected patients. With the continuing increase in HIV-positive individuals, it is important that practising dentists become familiar with the clinical features of HIV-associated oral diseases to facilitate early diagnosis and appropriate therapy.

Female↗
PubMed1987

Effects of ECT given two vs. three times weekly.

The benefits and side effects of electroconvulsive therapy (ECT) given two vs. three times per week were examined in depressed inpatients. Twenty subjects were randomly assigned to one of two treatment conditions (unilateral ECT two or three times weekly). Examiners without knowledge of treatment condition rated depression and psychiatric status and administered tests of memory and visual-motor problem solving; subjects also provided self-ratings of depression. Measures were collected before treatment and 2 and 4 weeks after treatment began. Both schedules of treatment produced significant and equivalent improvements in psychiatric symptomatology, but visual memory impairment was significantly lower in the twice-weekly group.

Depressive Disorder↗