Pulmonary effects of exposure to pig barn air

Swine production has undergone rapid transformation from family owned operation to a large scale industrial enterprise. Since increasing number of pigs are reared on a large scale in confined buildings, some of the swine barn workers may be employed to work eight hours per day. Swine barn workers suffer from higher incidences of impaired air flow and lung inflammation, which is attributed to high intensity and interrupted exposures to pig barn air. The air in these barns contains gases, dust, microbes and endotoxin with endotoxin being the major suspect as the cause of lung dysfunction. This review attempts to describe the current state of knowledge of incidences and mechanisms of pulmonary dysfunction following exposure to the barn air.     

Endoscopic pituitary surgery - a. beginner’s guide

Endonasal endoscopic surgery is now the preferred technique to tackle pituitary tumours. Our paper describes the stepwise endoscopic approach for surgeons embarking on pituitary surgery. It also highlights the common pitfalls encountered during surgery and the ways to avoid them. One must proceed in a gradual step- wise manner starting from simple exposure of the sphenoid sinus to complete endoscopic tumour removal so us to gain the neurosurgeon’s confidence as well as develop our own skills, confidence and ability to tackle complications. We use the endonasal paraseptal trans- sphenoidal approach. Surgery begins with gentle packing between the middle turbinate and septum to expose the anterior sphenoid wall and expose the sphenoid astium. The ostitum is then widened inferiorly and onto the opposite side to expose both sphenoid sinuses. The inter- sphenoid sinus and necessary mucosa is removed to expose the sella. We then use a bone flap technique or punches to open the sella. After incising the dura, tumour is removed with a suction curette. An endoscope holder facilitates the operation. The bone flap is replaced at the end of surgery to reconstruct the sella. This is especially important if a CSF leak is present. Nasal packing is usually not required.     

Bancroftian filariasis in Pondicherry, south India--epidemiological impact of recovery of the vector population.

An Integrated Vector Management (IVM) strategy was implemented from 1981 to 1985 in one part of Pondicherry, South India, for the control of the bancroftian filariasis vector Culex quinquefasciatus (the IVM area). The rest of the town (the comparison area) received the conventional larvicidal input. After 1985 both the areas were managed conventionally. The switch to conventional strategy resulted in an increase of vector density in both areas. The microfilaraemia prevalence in humans showed a general decline (P less than 0.05) from 1986 to 1989 only in the IVM area whereas its intensity did not change significantly in either area. While the age-specific rate of gain of infection was generally unchanged in the IVM area, an increase in all age classes was observed after 1985 in the comparison area, where the Annual Transmission Index was high during the previous years. In both areas the rate of loss of infection increased during 1986-9 compared to 1981-6. The results suggest that 3 years is too short a period to relate the changes in entomological parameters to those in the microfilaraemia status of the population.     

Past exposure and the dynamics of lymphatic filariasis infection in young children.

This study utilizes parallel, longitudinal entomological and parasitological data collected during a 5-year vector control programme in Pondicherry, South India, to quantify Wuchereria bancrofti transmission from the vector to the human population. A simple mathematical model, derived from the standard catalytic model, is used to examine the hypothesis that current infection prevalence in young children is a dynamical function of their cumulative past exposure to infective bites. Maximum likelihood fits of the model to the observed data indicate a constant child infection rate with age, above a threshold representing the pre-patent period, or equivalently, the cumulative biting intensity required to produce patent infections. Extrapolation of the model allows the crude estimation of the equilibrium microfilaria age-prevalence curve due to control. The results suggest that vector control alone may have little impact on the overall age-prevalence of infection even when sustained for long periods. These observations are discussed in terms of the likely impact of density dependent mechanisms, such as acquired immunity, on model predictions.     

Hepatocyte proliferation is the possible mechanism for the transient decrease in liver injury during steatosis stage of alcoholic liver disease

Steatosis is a frequent pathologic stage in alcoholic liver disease (ALD). Although the mechanisms for increased susceptibility of steatotic liver to injury have been postulated, the ability of these hepatocytes to proliferate and withstand injury is unknown. There are conflicting reports on the status of hepatocyte regeneration following chronic alcohol ingestion. Hence, the objective of this study was to investigate the temporal dynamics between the pattern of liver injury and hepatocyte proliferation during the steatosis stage of ALD. Alcoholic steatosis was induced in male Sprague-Dawley rats by feeding an ethanol (EtOH)-containing Lieber-DeCarli liquid diet for a period of 5 weeks. Microvesicular steatosis was evident in H&E sections by three weeks in the EtOH-treated rats, which further developed into panlobular macrovesicular steatosis by 5 weeks. Plasma transaminase activities indicated progressive increase in liver injury peaking at 3 weeks with significant but mild decrease at 4 and 5 weeks. CYP2E1 protein and activity was significantly increased in EtOH-fed rats as measured by Western blot and pNP hydroxylation assay. PCNA analysis of liver sections indicated that EtOH-treated rats had a significantly higher number of cells in S phase of cell division at weeks 1 (3.20 +/- 0.19), 2 (7.03 +/- 0.92), and 3 (4.23 +/- 1.41) when compared to controls (1.5 +/- 0.22). NF-kappaB DNA binding and Cyclin D1 proteins increased significantly in the EtOH-treated rats corresponding with enhanced hepatic proliferation. These data suggest the transient decline in liver injury during alcoholic steatosis is due to enhanced NF-kappaB-dependent hepatocyte proliferation.     

Pharmacological studies on nitro‐naproxen (naproxen‐2‐nitrooxyethylester)

Naproxen‐2‐nitrooxyethylester (S‐(+)‐2‐(6‐methoxy‐2‐naphthyl)propanoic acid‐2‐nitrooxyethylester, LE‐EK06) was synthesized from naproxen and 2‐nitrooxyethylbromide as a novel nitric oxide–releasing derivative of naproxen. Molar equivalents of LE‐EK06 (6.93–27.73 mg/kg, p.o.) to naproxen dose‐dependently exhibited greater antinociceptive activity in comparison to naproxen in a writhing assay. The compound (5.54–22.18 mg/kg, p.o.) showed greater anti‐inflammatory activity at 2 h after as comparable to its effect at 4 h after carrageenan challenge in rats. Further, LE‐EK06 (9.45 mg/kg, p.o.) was more potent in the carrageenan‐evoked hyperalgesia. LE‐EK06 (11.09 mg/kg, p.o.) and naproxen (8.0 mg/kg, p.o.) showed a comparable inhibitory effect on exudate formation and migration of polymorphonuclear leukocytes (PMNs) in a carrageenan‐induced pleurisy test. Further, the compound (11.09 mg/kg, p.o.) significantly reduced myeloperoxidase activity in carrageenan‐treated paw and demonstrated significantly less gastrotoxicity in acute and chronic (21 days) studies. The scanning electron microscopy revealed that LE‐EK06 showed only mild gastric damage (slight disruption of mucus layer) in comparison to naproxen. The present study suggested that naproxen‐2‐nitrooxyethylester (LE‐EK06) represents a novel gastric sparing NSAID. Drug Dev. Res. 61:66–78, 2004. © 2004 Wiley‐Liss, Inc.     

Effect of tertiary multileaf collimator (MLC) on foetal dose during three-dimensional conformal radiation therapy (3DCRT) of a brain tumour during pregnancy.

BACKGROUND AND PURPOSE: The aim of this work was to measure the dose to foetus both in vivo and in vitro during three-dimensional conformal radiation therapy (3DCRT) in a pregnant patient with a pituitary adenoma. The study was then extended to assess the components contributing to the foetal dose such as collimator scatter, internal scatter, head leakage, wedge scatter and multileaf collimator (MLC) effect. PATIENTS AND METHODS: A 30-year-old pregnant woman with a non-functioning pituitary macroadenoma was planned for 3DCRT with 6MV X-ray using four equally weighted MLC-shaped non-coplanar wedged portals. In vivo dosimetry was carried out using thermoluminescent (TL) phosphor powder, which was placed at different positions on the patient, corresponding to different locations in the uterus and also at external os. In vitro measurements were also performed on a simulated phantom using the same set-up parameters and beam arrangement to verify the in vivo measured dose. Experiments were carried out to measure the respective contributions of different components towards peripheral dose. RESULTS: In vitro measured dose to foetus was found to be slightly more than that of in vivo measurement with a maximum of 0.044% of the prescribed dose of 45Gy, which corresponded to 0.0199+/-0.0008Gy. Thermoluminescence dosimeter (TLD) kept at the external os of the patient showed a dose of 0.031% of the prescribed dose. Among the various components of the peripheral dose (foetal dose) measured, head leakage was found to be the leading cause contributing 52%, followed by wedge scatter (31%), collimator scatter (14%) and internal scatter (13%). The use of MLC reduced not only the volume of normal brain irradiation as compared to open fields but also the peripheral dose by 10%. CONCLUSION: Radiotherapy of brain tumours during pregnancy poses a unique clinical situation and decisions to deliver radiotherapy should be taken after detailed in vitro and in vivo dosimetric measurements. Our findings suggest that the beam arrangement using 3-4-fields generally used for 3DCRT of brain tumour with MLC for optimal coverage can be employed for pregnant patients even in early trimester. A possible increase in foetal dose from wedges to a large extent can be compensated with the use of MLC.