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Biomedical subjects

P Moriarty

Publications and source records attributed to P Moriarty.

At least 19 recordsLinked to original sources
PubMed2004

Iron wheels on silicon: wetting behavior and electronic structure of adsorbed organostannoxane clusters.

Atomic force microscopy and synchrotron radiation (SR) spectroscopy have been used to study the wetting behavior and electronic structure of thin films of a novel organometallic cluster--[BuSn(O)OC(O)Fc]6 ("Fc" = ferrocenyl)--on silicon substrates. This cluster comprises six ferrocene units connected to a stannoxane central core--"an iron wheel on a tin drum" (V. Chandrasekhar; et al. Angew. Chem., Int. Ed. 2000, 39, 1833). Thin films spin-cast onto native oxide-terminated silicon readily dewet the substrate. We have utilized advanced image analysis techniques based on Minkowski functionals to provide a detailed quantitative analysis of the morphology of the stannoxane overlayers. This analysis shows that the dewetting patterns are rather far removed from those expected to arise from a simple Poisson distribution of centers, and we discuss the implications of this finding in terms of nucleated and spinodal dewetting. Variations in both the surface roughness and the in-plane correlation length have been followed as a function of annealing time to probe the surface dewetting dynamics. SR valence band photoemission illustrates that the highest occupied molecular orbital (HOMO) of the cluster is found 2 eV below the Fermi level. Fe 2p --> 3d and Sn 3d --> 5p resonant photoemission spectroscopy have been used to enhance the cross sections of the partial density of states associated with the Fe and Sn atoms. Sn atoms make a large contribution to the HOMO of the cluster, whereas the Fe atoms are associated with an electronic environment seemingly very similar to that in the "parent" ferrocene molecule.

Journal Article↗
PubMed2004

Ocular toxocariasis in schoolchildren.

Ocular toxocariasis in humans is typically a unilateral disease caused by second-stage larvae of the Toxocara species. Serological evidence of widespread infection in humans provides little information on clinical disease. There is only a single previous estimate of the prevalence of ocular toxocariasis (from Alabama). The present survey examined the extent of consultant-diagnosed toxocaral eye disease among a population of schoolchildren. More than 120,000 participants were surveyed by questionnaire and follow-up. Two sets of control subjects from the same school and from the same county were compared with persons who had ocular toxocariasis. The prevalence of consultant-diagnosed toxocaral eye disease was 6.6 cases per 100,000 persons when only cases regarded as definite by the consultant ophthalmologist were included. This increased to 9.7 cases per 100,000 persons when both definite and strongly suspected cases were included. Geophagia and a history of convulsion were associated with toxocaral eye disease in both of the case-control studies.

Adolescent↗
PubMed2002

Nanostructured cellular networks.

Au nanocrystals spin-coated onto silicon from toluene form cellular networks. A quantitative statistical crystallography analysis shows that intercellular correlations drive the networks far from statistical equilibrium. Spin-coating from hexane does not produce cellular structure, yet a strong correlation is retained in the positions of nanocrystal aggregates. Mechanisms based on Marangoni convection alone cannot account for the variety of patterns observed, and we argue that spinodal decomposition plays an important role in foam formation.

Cell Aggregation↗
PubMed2001

Isolated bilateral orbital neurofibromatosis in a twelve-year-old.

A patient with bilateral orbital neurofibromatosis is described. This patient had no other dysmorphic features and no systemic stigmata indicative of Von Recklinghausen's disease or endocrine syndromes. To our knowledge, this is the first report in the literature of isolated bilateral orbital neurofibromatosis in an otherwise normal patient.

Blepharoptosis↗
PubMed2000

Calcium homeostatic pathways change with gestation in human myometrium.

A rise in intracellular calcium is the primary trigger for contractile activity in pregnant human myometrium. It is hypothesized that key proteins involved in myometrial calcium homeostasis are gestationally regulated and play an important role in the preparation for labor. The aims of the study were to investigate the role of sarcoplasmic reticulum Ca ATPases (SERCAs) in regulating spontaneous contractile activity in myometrium, and to determine the expression of SERCA isoforms 2a and 2b, and the plasma membrane Ca ATPase (PMCA), at term and during labor. Western blot analysis demonstrated that the expression of SERCA 2a and 2b significantly increased in myometrium of women in labor compared with those not in labor. The augmentation of contractile activity in laboring myometrium in the presence of a SERCA 2 inhibitor, cyclopiazonic acid (CPA), demonstrated the functional significance of this observation. It is interesting that the application of CPA in the presence of a calcium-activated potassium channel inhibitor to term nonlabor myometrium mimicked the response of myometrium from women in active labor to CPA alone. We conclude that the activity of SERCA isoforms becomes increasingly important in the maintenance of regular contractile activity during labor and may compensate for the functional loss of other calcium control pathways at term.

Blotting, Western↗
PubMed1999

Simultaneous X-Ray and TeV Observations of a Rapid Flare from Markarian 421.

Mrk 421 was observed for about 2 days with BeppoSAX in 1998 April as part of a worldwide multiwavelength campaign. A large, well-defined flare was observed in X-rays. The same flare was observed simultaneously at TeV energies by the Whipple Observatory gamma-ray telescope. These data provide (1) the first evidence that the X-ray and TeV intensities are well correlated on timescales of hours and (2) the first exactly simultaneous X-ray and TeV spectra. The results imply that the X-ray and TeV photons derive from the same region and from the same population of relativistic electrons. The physical parameters deduced from a homogeneous synchrotron self-Compton model for the spectral energy distribution yield electron cooling times close to the observed variability timescales.

Journal Article↗
PubMed1999

Ocular adnexal lymphoma-comparison of MALT lymphoma with other histological types.

AIMS: To correlate histological features of ocular adnexal lymphoma using the revised European American lymphoma classification (REAL), with stage of disease at presentation, treatment modalities, and patient outcome. MALT lymphoma defines an extranodal marginal zone B cell lymphoma as outlined in the REAL classification. Comparison groups of patients included those with primary ocular adnexal MALT lymphoma versus primary ocular adnexal lymphomas of other types, MALT lymphoma versus non-MALT lymphomas (primary and secondary), and primary ocular adnexal lymphoma (MALT lymphomas and other types) versus secondary ocular adnexal lymphomas. METHODS: A retrospective review of the National Ophthalmic Pathology Laboratory records identified 20 cases of ocular adnexal lymphoma over a 10 year period which were reclassified using appropriate immunohistochemical stains. Patients' medical records were examined for data including stage of the disease at presentation, mode of treatment, and patient outcome. RESULTS: Among the 20 cases identified 14 had primary ocular adnexal lymphomas. 10 of the primary lymphomas had histological features of MALT lymphoma. One case was a primary ocular adnexal T cell lymphoma, one a follicular centre, follicular B cell lymphoma, and two were large cell B cell lymphomas. Six cases had systemic disease, four large B cell, one follicular centre, follicular B cell, and one mantle cell. A significantly higher proportion of patients with MALT lymphomas had early disease (p = 0.005), initially required local treatment (p = 0.005) and were alive at last follow up (p = 0.001) than those without. Two patients with MALT lymphoma had recurrence of lymphoma which responded to further treatment. CONCLUSIONS: Patients with primary ocular adnexal MALT lymphomas present with localised disease requiring local treatment and have a better outcome compared with patients with other types. As a small percentage of these tumours recur, patients should be followed up indefinitely.

Adult↗
PubMed1998

Nasolacrimal intubation in adults.

BACKGROUND/AIMS: Silicone intubation has been shown to be successful in the management of epiphora in children. The effectiveness of this procedure was assessed in adults. METHODS: 70 eyes from 53 patients underwent nasolacrimal intubation. Mean age at intubation was 54.7 years. Mean follow up period was 15 months. The results were based on improvement of symptoms. RESULTS: Complete resolution of symptoms was reported in 54.3%. A partial improvement was reported in 14.3%, a transient improvement in 10%, and no improvement in 21.4%. A better outcome was associated with canalicular than with nasolacrimal obstructions (complete resolution of symptoms in 75.9% versus 25%). Only 17.1% have subsequently required dacryocystorhinostomies. CONCLUSION: Silicone intubation of the nasolacrimal system is a successful procedure in the management of adult epiphora.

Adolescent↗
PubMed1997

Characterization of cholecystokininA and cholecystokininB receptors expressed by vagal afferent neurons.

The cholecystokinin receptors expressed by vagal afferent neurons mediate the effect of cholecystokinin in inhibiting food intake and gastric emptying. We have determined the relative abundance of cholecystokininA, gastrin-cholecystokininB and gastrin-cholecystokininC receptor populations in the rat vagus by autoradiography using [125I]Bolton Hunter-cholecystokinin-8, [125I]Bolton Hunter-heptadecapeptide gastrin and [125I]Leu(15)2-17Glycine-extended heptadecapeptide gastrin, together with the selective antagonists devazepide and L-740093. The results indicate approximately three-fold higher abundance of cholecystokininA compared with gastrin-cholecystokininB receptors, and no significant representation of gastrin-cholecystokininC receptors. Topical capsaicin applied to the vagal nerve trunk abolished the accumulation of sites binding both [125I]Bolton Hunter-labelled cholecystokinin-8 and heptadecapeptide gastrin indicating that both cholecystokininA and gastrin-cholecystokininB receptor populations were present on afferent fibres. The molecular identity of the receptors expressed by rat and human nodose ganglia was examined using the reverse transcription polymerase chain reaction. Products of the predicted size for the cholecystokininA and gastrin-cholecystokininB receptors were identified. The human and rat cholecystokininA receptor products were cloned and the sequences were found to be 99% homologous to those published for receptors expressed by rat pancreas and human gall bladder. We conclude that cholecystokininA and gastrin-colecystokininB receptors are synthesized by nodose ganglion cells, and that the receptor proteins are transported to the periphery along afferent fibres. While there is a clear role for vagal cholecystokininA receptors, the function of vagal afferent gastrin-cholecystokininB receptors remains to be determined.

Afferent Pathways↗
PubMed1997

Intravitreal growth factors in proliferative diabetic retinopathy: correlation with neovascular activity and glycaemic management.

AIM: Many growth factors are implicated in proliferative diabetic retinopathy (PDR). It was decided to test the hypothesis that no one factor is predominant but that a regular profile of levels of different growth factors might be operating, and that the profile might differ according to whether or not insulin therapy was part of the patient's glycaemic management. The levels of several growth factors in vitrectomy samples were therefore determined from diabetic patients with tractional, non-haemorrhagic sequelae of PDR and these levels were correlated with (a) each other (growth factor profile), (b) neovascular activity, and (c) the method of glycaemic management (insulin treated (IT) or non-insulin treated (NIT)). METHODS: 72 samples of vitreous were obtained from either diabetic patients with PDR (n = 51) or non-diabetic (control) patients (n = 21). Levels of bFGF, IGF-I, EGF, and insulin were determined by radioimmunoassay; levels of TGF-beta 2 by ELISA; and levels of IGF-I binding protein by western ligand blotting. The data were analysed using appropriate statistics. RESULTS: There was no regular growth factor profile. bFGF levels were significantly greater in vitreous from NIT patients compared with IT patients and controls. The highest levels of bFGF were found in NIT patients with actively vascularised membranes. TGF-beta 2 levels were significantly greater in vitreous from IT patients compared with NIT patients and controls The highest levels of TGF-beta 2 were found in IT patients with actively vascularised membranes. IGF-I levels were significantly greater in diabetics (irrespective of insulin treatment) than non-diabetics and the highest levels of IGF-I were found in IT patients with actively vascularised membranes. A 34 kDa IGFBP was the predominant IGFBP identified in vitreous and was found to be elevated in diabetics patients. CONCLUSION: In PDR there is a correlation between intravitreal growth factor levels and both disease state (whether active or fibrotic) and method of glycaemic management.

Analysis of Variance↗