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Biomedical subjects

M R Darling

Publications and source records attributed to M R Darling.

At least 19 recordsLinked to original sources
PubMed2006

Osteopontin expression in salivary gland tumours.

Osteopontin (OPN) is expressed in numerous carcinomas and plays a role in tumour development, invasion and metastasis. This study examines by immunohistochemistry the expression of OPN in normal salivary gland tissue and three types of salivary gland tumour: pleomorphic adenoma (PA), adenoid cystic carcinoma (ACC) and polymorphous low grade adenocarcinoma (PLGA). PAs and PLGAs demonstrated higher levels of OPN than normal salivary gland tissue, while ACC, although showing a trend towards increased OPN, was not significantly different. The results of this study indicate that OPN expression is present in normal salivary gland tissue, and is increased in certain salivary gland tumours, but further investigation is necessary to clarify its role.

Adenocarcinoma↗
PubMed2006

Peripheral ameloblastic fibroma.

Peripheral ameloblastic fibroma is an exceedingly rare lesion. Only three reports could be found, two of which appeared in the Japanese literature. Here, we report a case of peripheral ameloblastic fibroma occurring in a 5-year-old girl. The diagnosis was made after careful microscopic examination, to exclude other lesions. The lesion was excised and has not recurred 1 year after removal.

Age Distribution↗
PubMed2005

Human kallikrein 6 expression in salivary gland tumors.

Human kallikrein 6 (hK6), also known as zyme/protease M/neurosin), is expressed in many normal glandular tissues. The aim of this study was to determine whether hK6 is expressed in salivary gland tissues and salivary gland tumors (both benign and malignant), using an immunohistochemical method. Pleomorphic adenomas (PA), adenoid cystic carcinomas, polymorphous low-grade adenocarcinomas, acinic cell carcinomas, mucoepidermoid carcinomas, and adenocarcinomas not otherwise specified of both minor and major salivary glands were examined. Cells lining duct-like structures and non-duct-like cells were scored. Only in PA of minor salivary gland origin was overall staining higher in duct-like than in non-duct-like cells. In all other tumors exhibiting both types of cells, hK6 staining was similar in both duct-like and non-duct-like cells. Tumors that exhibited non-duct-like cells only also exhibited cytoplasmic staining. Results of this study show that salivary gland tumors express hK6, apparently downregulated in comparison with normal salivary gland tissue, and that this expression is not specific for any of the tumors studied.

Down-Regulation↗
PubMed2001

Human vaginal epithelium and the epithelial lining of a cyst model constructed from it: a comparative light microscopic and electron microscopic study.

The light microscopic features and keratin filament distribution of human vaginal epithelium resemble those of buccal mucosa. We used vaginal epithelium to establish a human cyst model in immunodeficient mice. To strengthen the view that this experimental cyst is a suitable model to study mucosal diseases, we compared specific light microscopic and ultra-structural features of vaginal epithelium and the epithelial lining of the cyst. Nineteen cyst walls and 6 specimens of vaginal mucosa, which had been used to establish the cysts, were examined. We counted the number of cell layers of 17 cyst linings and the 6 vaginal specimens. Surface keratinisation was evaluated on sections stained with the Picro-Mallory method. To demonstrate intercellular lamellae and membrane coating granules 2 cyst linings were examined ultra-structurally. The epithelium lining of the cyst wall was thinner than that of vaginal mucosa but the surface keratinisation and ultra-structural features of the intercellular lamellae and membrane coating granules were similar. We concluded that vaginal mucosa is a useful substitute for oral mucosa in the cyst model.

Actin Cytoskeleton↗
PubMed2000

The relationship between increased folate catabolism and the increased requirement for folate in pregnancy.

OBJECTIVES: To estimate the rate of folate catabolism in pregnant and nonpregnant women and to derive the recommended dietary allowance for folate. DESIGN: Prospective, observational study. SETTING: Rotunda Hospital, Dublin. WOMEN: Twenty-four healthy gravid women were studied once during each trimester and postpartum. Twenty-five nonpregnant controls were assessed before and after folic acid supplementation. INTERVENTIONS: Women provided 24-hour urine collections while adhering to a strict dietary regimen containing no exogenous folate catabolites. MAIN OUTCOME MEASURES: Urinary levels of p-acetamidobenzoylglutamate and p-aminobenzoylglutamate were measured by high pressure liquid chromatography. RESULTS: The 24-hour excretion of folate catabolites, expressed as mean [95% CI] folate equivalents in microg) progressively increased during pregnancy. A peak was reached in the third trimester (349.1 microg [308.1 to 390.1]) where the rate was more than twice the rate in the nonpregnant control group (136.4 microg [112.4 to 160.4]) (P < 0.001). Based on our results the recommended dietary allowance for folate in nonpregnant women should be 250 microg and this should rise during pregnancy to 430 microg in the second trimester and 540 microg in the third trimester. CONCLUSIONS: The rate of folate catabolism progressively increases during pregnancy reaching a peak in the third trimester at the time of maximal fetal growth. The increased demand for folate during pregnancy appears to be due to the accelerated breakdown of the vitamin because of its participation in cellular biosynthesis. These results provide a quantitative basis for the current debate on the appropriate recommended dietary allowance for folate in both pregnant and nonpregnant women.

4-Aminobenzoic Acid↗
PubMed1999

Nitric oxide in the uteroplacental, fetoplacental, and peripheral circulations in preeclampsia.

OBJECTIVE: Altered production of nitric oxide by the vascular endothelium may influence the pathogenesis of preeclampsia. The aim of this study was to measure circulating levels of nitric oxide metabolites (nitrites) in the uteroplacental, fetoplacental, and peripheral circulation of preeclamptic pregnancies compared with normotensive controls. METHODS: Fifteen women with preeclampsia were compared with 16 women with normotensive pregnancies. At cesarean, blood samples were taken from the uterine vein draining the placental site, the umbilical vein, and the antecubital vein after delivery of the baby but before delivery of the placenta. Plasma nitrites were measured using the Greiss reaction after conversion of plasma nitrates to nitrites using nitrate reductase. RESULTS: Nitric oxide metabolites were higher in the uteroplacental (P < .01), fetoplacental (P < .001), and peripheral (P < .02) circulations in samples from preeclamptic pregnancies compared with control pregnancies. In samples from the fetoplacental circulation only, nitric oxide metabolite levels were negatively correlated with gestational age (r = -.489, P < .01) and birth weight (r = -.544, P < .004). Nitric oxide metabolite levels were not significantly correlated with blood pressure, placental weight, or maternal age. CONCLUSION: In established preeclampsia, production of nitric oxide was higher in the uteroplacental, fetoplacental, and peripheral circulation than in normotensive pregnancies. This increase may be part of a compensatory mechanism to offset the pathologic effects of preeclampsia.

Adult↗
PubMed1998

Circulating vascular cell adhesion molecule-1 in pre-eclampsia, gestational hypertension, and normal pregnancy: evidence of selective dysregulation of vascular cell adhesion molecule-1 homeostasis in pre-eclampsia.

OBJECTIVE: Our purpose was to investigate circulating levels of vascular cell adhesion molecule-1 in the peripheral and uteroplacental circulations during normotensive and hypertensive pregnancies. STUDY DESIGN: This prospective observational study involved 2 patient groups. Group 1 consisted of 22 women with pre-eclampsia and 30 normotensive women followed up longitudinally through pregnancy and post partum. There were an additional 13 women with established gestational hypertension. Group 2 consisted of 20 women with established pre-eclampsia and 19 normotensive control subjects undergoing cesarean delivery. Plasma levels of vascular cell adhesion molecule-1 were measured in blood drawn from the antecubital vein (group 1) and from both the antecubital and uterine veins (group 2). Data were analyzed by analysis of variance. RESULTS: In group 1 vascular cell adhesion molecule-1 levels did not change significantly throughout normal pregnancy and post partum. Women with established pre-eclampsia had increased vascular cell adhesion molecule-1 levels compared with the normotensive pregnancy group (P = .01). Vascular cell adhesion molecule-1 levels were not elevated in women with established gestational hypertension. In group 2 significantly higher levels of vascular cell adhesion molecule-1 were detected in the uteroplacental (P < .0001) and peripheral (P < .0001) circulations of pre-eclamptic women by comparison with normotensive women. In the pre-eclamptic group there was a tendency toward higher vascular cell adhesion molecule-1 levels in the peripheral circulation than in the uteroplacental circulation (P = .06). In contrast to vascular cell adhesion molecule-1, circulating levels of E-selectin and intercellular adhesion molecule-1, other major leukocyte adhesion molecules expressed by the endothelium, were not different in pre-eclamptic and normotensive pregnancies. CONCLUSION: Established pre-eclampsia is characterized by selective dysregulation of vascular cell adhesion molecule-1 homeostasis. This event is not an early preclinical feature of pre-eclampsia, does not persist post partum, is not a feature of nonproteinuric gestational hypertension, and is not observed with other major leukocyte adhesion molecules. Induction of vascular cell adhesion molecule-1 expression in pre-eclampsia may contribute to leukocyte-mediated tissue injury in this condition or may reflect perturbation of other, previously unrecognized, functions of this molecule in pregnancy.

Adult↗
PubMed1998

Hemostasis in the uteroplacental and peripheral circulations in normotensive and pre-eclamptic pregnancies.

OBJECTIVE: Our purpose was to determine the hemostatic changes in the uteroplacental and peripheral circulations in normotensive and pre-eclamptic pregnancies. STUDY DESIGN: This prospective, observational study involved 2 patient groups. Group 1 consisted of 30 normotensive women and 22 women with pre-eclampsia who were followed up longitudinally through pregnancy and post partum. Group 2 consisted of 20 women with established pre-eclampsia and 19 normotensive control subjects, all undergoing cesarean section. Plasma levels of thrombin-antithrombin III complex, soluble fibrin, plasmin-alpha2-antiplasmin complex, and fibrin-degradation product (D-dimer) were measured in blood drawn from the antecubital vein (group 1) and from both the antecubital and uterine veins (group 2). Data were analyzed by analysis of variance. RESULTS: In group 1 levels of thrombin-antithrombin III complex, soluble fibrin, and fibrin-degradation product were significantly higher during normal pregnancy than at 6 weeks post partum. Plasmin-alpha2-antiplasmin complex levels did not change. No differences between the pre-eclamptic and normotensive pregnancy groups were found for any of the hemostatic markers. In group 2 normotensive women undergoing cesarean section, thrombin-antithrombin III complex and soluble fibrin levels were significantly higher in the uterine vein than in the antecubital vein. In group 2 women with pre-eclampsia, thrombin-antithrombin III complex and fibrin-degradation product levels were significantly higher in the uterine vein than in the antecubital vein. In addition, plasmin-alpha2-antiplasmin complex and fibrin-degradation product levels were higher and soluble fibrin levels were lower in the uterine vein in the pre-eclamptic group than in the normotensive group. CONCLUSION: Both the coagulation and fibrinolytic systems are activated during normal pregnancy. Activation of these systems is more marked in the uteroplacental circulation than in the systemic circulation in both normotensive and pre-eclamptic pregnancies. An abnormal pattern of hemostasis occurs in the uteroplacental circulation in pre-eclampsia.

Adult↗
PubMed1997

Can 24-hour ambulatory blood pressure measurement predict the development of hypertension in primigravidae?

OBJECTIVE: To assess the role of 24-hour ambulatory blood pressure measurement in the mid-second trimester as a predictive test for the development of hypertension in pregnancy. DESIGN: Prospective intervention. SETTING: The Rotunda Hospital, Dublin. PARTICIPANTS: One thousand one hundred and two healthy primigravid women. INTERVENTION: 24-hour ambulatory blood pressure measurement at 18 to 24 weeks of gestation. MAIN OUTCOME MEASURES: The development of pre-eclampsia or gestational hypertension. RESULTS: A total of 1048 women had sufficient readings to be included in the final analysis. Of these, 23 (2.2%) developed pre-eclampsia, 64 (6.1%) developed gestational hypertension and 961 (91.7%) remained normotensive. Significantly higher ambulatory blood pressures were recorded in both the pre-eclamptic and gestational hypertensive group compared with the normotensive group. In addition, the gestational hypertensive group had significantly higher clinically measured blood pressure compared with the normotensive group. There were no differences between the pre-eclamptic and the gestational hypertensive group for any of the blood pressure parameters analysed. The best overall predictor for pre-eclampsia was 24-hour mean diastolic pressure which using a cutoff level of 71 mmHg gave a test with a sensitivity of only 22% and a positive predictive value of 15%. CONCLUSION: Because the absolute differences are small and the overlap between the hypertensive and normotensive groups large, ambulatory blood pressure measurement, in a healthy primigravid population, between 18 and 24 weeks of gestation is not a useful predictor of hypertension.

Adult↗
PubMed1993

Effects of cannabis smoking on oral soft tissues.

The oral effects of cigarette smoking have been well documented but the effects of cannabis smoke on the oral environment have been poorly documented. Three-hundred cannabis/tobacco/methaqualone smokers were examined. Two control groups consisting of 152 tobacco- and 189 non-smokers respectively were examined similarly. Health of the oral tissues and oral dryness was recorded. Lesions present included leukoedema, leukoplakia and numerous others. The only significant differences between lesions and conditions noted in cannabis users and controls occurred with respect to leukoedema, dry mouth and traumatic ulcer.

Adult↗
PubMed1992

A descriptive study of pregnant women with gallstones. Relation to dietary and social habits, education, physical activity, height, and weight.

Five hundred and twelve women attending the antenatal clinic of the Rotunda Hospital of Dublin were studied by means of abdominal real time ultrasound (US) scanning to establish some of the characteristics of those subjects found to be gallstone-positive, compared to the gallstone-negative control population. Coffee, tea and sucrose consumption, dietary fats, attendance at fast-food restaurants, education, cigarette smoking, alcohol, and physical activity did not show any substantial differences between the two groups, while there was a significantly higher prevalence of cholelithiasis in women who had been dieting and in overweight subjects.

Adolescent↗
PubMed1992

Intrapartum asphyxia in term and post term infants.

Many attempts have been made to identify infants at risk of suffering asphyxial brain damage. In a retrospective review of records at the Rotunda Hospital over a five year period all infants who died or suffered seizures, presumed secondary to asphyxia, were compared with the general hospital population. Out of 28,655 deliveries reviewed, there were 13 deaths in infants at or after term associated with perinatal asphyxia, and 32 surviving infants had asphyxial seizures. Seizures were regarded as asphyxial in origin if they occurred in the first forty eight hours of life and were associated with other clinical evidence of asphyxia. The incidence of abnormal presentations, assisted breech deliveries, instrumental deliveries and emergency caesarean sections was all increased in the asphyxial categories compared to the control population. Referral to the fetal assessment unit was associated with a seizure rate of 0.16/1000 live births compared with a rate of 1.4/1000 in the remaining non referred hospital population. Nineteen percent of the infants who seized subsequently developed cerebral palsy. It would appear from our data that referral to the fetal assessment unit and the consequent assignment to "high risk" status is associated with low risk in terms of asphyxial outcome.

Asphyxia Neonatorum↗
PubMed1992

Review of the effects of cannabis smoking on oral health.

Cannabis is a drug which is abused worldwide, and so presents a social and health problem for many countries. There are several cannabis-associated oral effects of importance to the dental practitioner which are reviewed in this article. These include xerostomia (with predisposition to caries and periodontitis), severe gingivitis, oral mucosal disease, and an abnormal stress response upon administration of adrenalin-containing local anaesthetic.

Humans↗