Influence of Dispersants on the Bioavailability of Naphthalene from the Water-Accommodated Fraction Crude Oil to the Golden-Brown Algae, Isochrysis galbana

The golden-brown algae Isochrysis galbana, a primary producer, was used to determine the influence of the chemical dispersing agent, Corexit 9527^?, on the bioavailability of naphthalene. Cells were exposed to laboratory preparations of either the water-accommodated fraction (WAF) of Prudhoe Bay crude oil (PBCO) or a dispersed oil (DO) mixture of PBCO and Corexit 9527 spiked with [U-¹⁴C]naphthalene. Uptake was determined by the amount of algae-associated [¹⁴C]. High-pressure liquid chromatography (HPLC) co-chromatography was used to fractionate and identify metabolic products. A 24-h bioaccumulation factor (BAF) was calculated in the absence of steady state. The presence of Corexit 9527, had significant influence (p = 0.001) on the uptake of naphthalene, but no significant effect on the 24-h BAF (BAF: 168 and 180 from WAF and DO, respectively), or metabolic fate of naphthalene in I. galbana. Results of this research indicate that dispersants have the potential to increase organismal exposure to certain petroleum hydrocarbons without increasing their aqueous concentration. Received: 19 September 1997/Accepted: 5 February 1998     

Breast cancer awareness and knowledge assessment among men and women in Malaysia

Journal of Public Health - The prevalence of breast cancer cases in Malaysia is 1 in every 20 women. Comprehending the risk factors and causation of breast cancer as well as enabling early...     

Predictive and pre-natal testing for Huntington Disease in Australia: results and challenges encountered during a 10-year period (1994-2003)

This study summarizes 10-years' experience of predictive and pre-natal testing and pre-implantation genetic diagnosis (PGD) for Huntington disease (HD) in Australia. Results are presented from 2036 direct mutation predictive tests conducted between January 1994 and December 2003. Thirty-eight per cent of results (776/2036) were positive, 56% (1140/2036) were negative, and 6% (120/2036)) were in the mutable normal (27-35 CAG repeats) or in the reduced penetrance (36-39 CAG repeats) ranges. Ninety-four per cent (1908/2036) and 6% (128/2036) of those tested had prior genetic risks of 50% and 25%, respectively. Twenty-seven per cent (34/128) of those at 25% risk had their genetic status changed to positive, thus revealing the positive status of their at-risk parent. During this period, 63 pre-natal tests were also conducted, and 13 children were born following PGD for HD. Social workers specializing in predictive testing counselling over this 10-year period across Australia identified and summarized particularly challenging counselling issues. These included the interpretation of mutable normal and reduced penetrance range test results, potential conflicts of interest between family members regarding testing decisions, unanticipated consequences of both predictive and pre-natal testing decisions, the importance of following protocols for predictive testing to facilitate long-term adjustment to results, and the potential for genetic discrimination. The identified issues highlight the importance of the protocols for predictive testing and indicate that extension of the international guidelines published in 1994 may be timely.     

Nasofacial zygomycosis.

Zygomycosis is an uncommon polymorphic fungal disease. One clinical subtype, nasofacial zygomycosis, is caused by infectious exposure to the organism Conidiobolus coronatus. A case affecting the nose and lips of a 42-year-old Malay man is reported here. The clinicopathologic features and management of this disease are described, and its differential diagnosis is discussed.     

The inhibitory role of nitric oxide in the control of porcine and human sphincter of Oddi activity

Background—The possible role of nitric oxide inthe regulation of the sphincter of Oddi is not known in species with aresistor-like sphincter of Oddi such as humans and pigs.
Methods—Sphincter of Oddi perfusion manometry andsimultaneous electromyography (EMG) were recorded transduodenally ineight anaesthetised pigs. Acetylcholine (4 µg/kg) was givenintra-arterially, with or without sodium nitroprusside(10-100 µg/kg), an exogenous nitric oxide donor. For in vitrostudies the sphincter was removed from the eight pigs and from sixpatients undergoing pancreaticoduodenectomy, cut into rings, and theamplitude of contraction was measured in an ex vivo bath. Each ring wasstimulated with acetylcholine (100 µM) and KCl (125 mM). Thestimulation was repeated after incubation with L-NAME (astereospecific competitive inhibitor of nitric oxide synthase), withL-NAME plus L-arginine (a substrate for nitricoxide synthase), and with sodium nitroprusside. The sphincter ringswere then submersed in liquid nitrogen and stored. Immunohistochemicalanalysis was used to localise nitric oxide synthase in the pig andhuman sphincter specimens.
Results—In vivo EMG revealed 2-3 phasic burstsper minute with the basal pressure variation 6-40 mm Hg.Acetylcholine induced a large electrical burst and the pressureincreased by (mean (SE)) 20 (10) mm Hg (p <0.01) for 17 (4) seconds.After sodium nitroprusside (10 µg/kg) acetylcholine did not inducepressure changes and electrical activity was almost abolished. Invitro, L-NAME increased the KCl induced sphinctercontraction in both pig and human specimens (p<0.01). In human, butnot in pig, specimens L-NAME increased the amplitude ofacetylcholine induced contraction (p<0.01). L-Arginine partly reversed the effect of L-NAME in both pig and humanspecimens. Sodium nitroprusside decreased the acetylcholine and KClinduced contractions in both pig and human specimens.Immunohistochemical studies localised nitric oxide synthase to richplexi of nerve fibres in the mucosa and the muscle in both pig andhuman sphincter of Oddi.
Conclusions—The sphincter of Oddi in both pigs andhumans has endogenous nitric oxide synthase activity andimmunoreactivity. Inhibition of endogenous nitric oxide productionenhances contractility while exogenous nitric oxide decreasessphincter contractility and electrical activity.

Keywords:NO; nitric oxide synthase; nitroprusside; sphincterof Oddi; pig; human

     

Innervation of an Esophageal Ectatic Submucosal Blood Vessel in Achalasia and a Comparison with Normals

Achalasia is a disease of the esophagus characterized by incomplete relaxation of the lower esophageal sphincter, resulting in obstruction. Aperistalsis and dilation of the esophageal hody occurs later, contributing to the esophageal dysfunction. Gastrointestinal bleeding in acbalasia is an infrequent complication usually caused by stasis ulcer, esophageal varices, carcinoma, or pneumatic dilation of the sphincter. We describe here a patient with longstanding achalasia who bled vigorously from a proximal esopbageal site that can be identified as arterial bleeding by endoscopy. Subsequent esopbageal resection allowed detailed histological and immunohistochemical examination, which revealed a vascular ectasia. This lesion was associated with an unusually rich network of nerve fibers containing calcitonin generelated peptide. Neuropeptide Y- and substance P- containing fibers were found to be decreased in this lesion as compared with controls. On the other hand vasoactive intestinal peptide- and nitric oxide synthasecontaining fibers appeared quantitatively similar to those of controls. Calcitonin gene-related peptide is known to be involved in angiogenesis and may bave played a causative role in the development of this lesion. Vascular ectasia may represent a hitherto unreported complication of achalasia.     

A Severe Case of Diversion Colitis with Large Ulcerations

Diversion colitis is an inflammatory condition that develops in the excluded segment of colon after surgical diversion. Inflammatory changes include aphthous-type ulcerations, crypt abscesses, and mucosal friability. These features may be seen in other inflammatory diseases of the colon, making diagnosis difficult. Even though symptoms such as cramping pain, bleeding, and mucous discharge have been described with diversion colitis, most cases are asymptomatic. In this article we report a patient who presented with sepsis secondary to severe diversion colitis with several large (2-4 cm in diameter), deep ulceration.s and air in the colonic wall, requiring colectomy.     

Effects of Salinity and Temperature on the Bioavailability of Dispersed Petroleum Hydrocarbons to the Golden-Brown Algae, Isochrysis galbana

Comparative studies were done to determine the influence of a dispersant on the bioavailability of naphthalene from crude oil to the unicellular golden-brown algae, Isochrysis galbana, under changing temperature and salinity conditions. Conditions were selected to represent a range (two temperatures, 12 and 20°C, and two salinities, 22 and 34‰) encountered in Pacific waters, where extensive crude oil transport and refining occurs. Cells were exposed to laboratory preparations of either the water-accommodated fraction (WAF) of Prudhoe Bay crude oil (PBCO) or a dispersed oil (DO) mixture of PBCO and Corexit 9527? spiked with [U-¹⁴C]naphthalene. Uptake increased by as much as 50% in DO, 20°C exposures run at 22‰ (0.24 μmol naphthalene/g algae in WAF, 0.37 μmol naphthalene/g algae in DO) compared with comparable exposures at 34‰ (0.23 μmol naphthalene/g algae in WAF, 0.37 μmol naphthalene/g algae in DO). A 24-h bioaccumulation factor (BAF) calculated in the absence of steady state indicated increasing bioaccumulation with decreasing temperature. No significant variation in relative metabolite composition occurred under the different experimental conditions. Results of these experiments showed that the use of dispersants enhanced the uptake of naphthalene by microalgae under a variety of temperature and salinity conditions, independent of aqueous concentration. Received: 18 September 1997/Accepted: 5 February 1998     

Mucosal peptidergic innervation of the opossum esophagus and anal canal: a comparison with snout skin.

Nerves within and under the esophageal epithelium of the opossum esophagus were investigated morphologically with osmication and immunohistochemically for ten neuropeptides. The structurally similar but functionally diverse epithelia of the anal canal and snout skin, on which no immunohistochemical information exists, were similarly investigated for comparison. Total innervation was estimated from osmication, which revealed intraepithelial nerves in all three tissues in the following order of density: snout skin greater than anal canal greater than esophagus. Calcitonin gene-related peptide and substance P occurred in all three organs. The snout skin had intraepithelial galanin nerves but not vasoactive intestinal polypeptide, while conversely the esophagus and anal canal had vasoactive intestinal polypeptide but not galanin. All peptides found intraepithelially also occurred subepithelially. Calcitonin gene-related peptide, galanin, neuropeptide Y, substance P and vasoactive intestinal polypeptide subepithelial nerves occurred in all the tissues, while gastrin releasing peptide nerves occurred infrequently in the subepithelial regions of the esophagus and anal canal, but not the snout skin. As these epithelia neither secrete nor absorb, their nerves are presumably sensory. The peptides investigated could not account for all intraepithelial nerves demonstrated by osmium. Differences in the innervation of these epithelia may result from their differing sensory requirements.