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Biomedical subjects

P Naughton

Publications and source records attributed to P Naughton.

12 recordsLinked to original sources
PubMed2005

Spontaneous coronary artery dissection.

Spontaneous coronary artery dissection is a rare cause of myocardial ischaemia or sudden death, predominantly affecting young women with no known risk factors for cardiovascular disease. The case described emphasises the benefit of early diagnosis and the need to individualise management based on patient response to treatment.

Adult↗
PubMed2004

Neoadjuvant treatment of oesophageal adenocarcinoma.

Oesophageal adenocarcinoma is an enigma. It has emerged, seemingly from nowhere, in the late 20th century to dominate the oesophageal oncological landscape. This review will examine whether the current outcome for adenocarcinoma is as good as it gets or whether additional treatment is necessary and if so whether neoadjuvant therapy is effective.

Adenocarcinoma↗
PubMed2002

Interaction of heme with nitroxyl or nitric oxide amplifies heme oxygenase-1 induction: involvement of the transcription factor Nrf2.

Heme oxygenase-1 (HO-1) is a cytoprotective enzyme, the expression of which is highly sensitive to induction by pro-oxidant stimuli including the substrate heme and reactive oxygen species. Conceptually, the perception that HO-1 plays a key role in response to oxidative damage is paralleled by evidence showing high expression of HO-1 in a variety of cell systems challenged with nitric oxide (NO) or NO-derivatives, thus revealing a potential biological function for HO-1 against nitrosative stress. In this study, we report that exposure of cardiac cells to hemin (5-20 microM) in combination with compounds that liberate nitroxyl (HNO/NO-) or release NO significantly potentiates HO-1 mRNA and protein expression leading to a remarkable increase in heme oxygenase activity under both normoxic and hypoxic conditions. The amplification of the heme oxygenase pathway appears to involve a direct interaction between heme and the NO groups, as the ability of both NO(-)- and NO-releasing agents to induce HO-1 is totally lost by their pre-incubation for 1 hr in complete medium prior to cell treatment but is highly preserved by addition of hemin during the preincubation step. In addition, we show that the redox-sensitive transcription factor Nrf2 is highly expressed in the nuclear fraction of cells exposed to the NO- generator and that this effect is totally abolished by the presence of N-acetyl-L-cysteine. Interestingly, the expression of Nrf2 is gradually intensified by treating cells with a combination of the NO- releaser and increasing concentrations of hemin. Thus, a strict parallelism exists between the extent of HO-1 induction and expression of Nrf2 elicited by the heme-NO interaction. We propose that modification of the iron protoporphyrin centers by NO groups to modulate HO-1 expression might be regarded as a molecular switch to maximize heme oxygenase enzymatic activity and consequently mitigate the redox imbalance imposed by oxidative and nitrosative stress.

Acetylcysteine↗
PubMed1984

Two year longitudinal followup of premature infants weighing less than or equal to 1,200 grams at birth: sequelae of intracranial hemorrhage.

Intracranial hemorrhage (ICH) is a major problem for the premature infant, occurring in more than one-third of surviving infants weighing less than or equal to 1,500 g at birth. The literature on perinatal ICH, as it relates to neurodevelopment outcome, is briefly reviewed, and preliminary results from our two-year followup of 75 less than or equal to 1,200-g infants are summarized. An analysis of pathophysiology, diagnosis, classification, and followup indicates that risk for ICH and its sequelae increases as gestational age and birth weight decrease. Hydrocephalus apparently no longer presents significant risk beyond that conveyed by the original hemorrhage. However, persistent posthemorrhagic ventriculomegaly and/or periventricular abnormalities serve as significant "markers" of risk for neuromotor delay through two years of age. In contrast, recovery of normal ventricular morphology by term gestational age apparently indexes a degree of recovery from ICH and predicts a more normal developmental outcome through the first two postnatal years.

Birth Weight↗
PubMed1983

Adenosine and ATP effects on isolated guinea pig gallbladder.

Effects of adenosine, ATP and several derivatives of adenosine were measured in isolated strips of guinea pig gallbladder. Adenosine caused relaxations which were antagonized by theophylline and potentiated by an inhibitor of adenosine uptake, 6-(1-hydroxy-5-nitrobenzylthio)-guanosine (HNBTG). Among several adenosine derivatives, 2-chloroadenosine and 5'-N-ethylcarboxy-midoadenosine were similarly effective while 1-N6-phenylisopropyladenosine was only a weak relaxant. None of the derivatives caused maximal relaxations at 100 microM, and thus absolute potencies could not be determined. ATP caused predominantly contractile effects, with relaxations sometimes being evident at high concentrations. Indomethacin abolished contractile effects of ATP, suggesting prostaglandin involvement, and only relaxations were evident in its presence. Adenosine deaminase abolished the effects of adenosine and partly reduced the relaxant effects of ATP in the presence of indomethacin. In view of the low potency of adenosine and ATP, physiological roles for these compounds in gallbladder motility are not readily evident.

Adenosine↗
PubMedDate not supplied

Laparoscopic repair of a strangulated Bochdalek hernia.

BACKGROUND: Bochdalek herniae are rare. They are usually repaired by open abdominal surgery or by a thoracic video-assisted approach. When strangulated and in a compromised patient the options are fewer. AIM: To describe a case treated by a laparoscopic approach. RESULTS: The procedure was technically difficult, but the patient recovered without recurrence. CONCLUSION: Laparoscopic repair is possible even with strangulation.

Aged↗