Reactivity of natural organic matter with aqueous chlorine and bromine

While both aqueous bromine (HOBr/OBr(-)) and chlorine (HOCl/OCl(-)) react with natural organic matter (NOM) during water treatment, limited direct parallel comparison of bromine versus chlorine has been conducted. Experiments with model compounds and natural waters indicated more efficient substitution reactions with bromine than chlorine. Kinetic experiments with NOM isolates with and without pre-ozonation were conducted to obtain second-order rate constants (k) with bromine and chlorine. Two-stage reaction kinetics (rapid initial and slower consumption stages) were observed. Bromine reacted about 10 times faster than chlorine with NOM isolates during both stages. The rapid initial stage reactions were too fast to quantify k values, but qualitative estimates ranged between 500 and 5000 M(-1)s(-1). For the slower second stage k values for bromine were 15 to 167 M(-1)s(-1) over the pH range of 5-11, and lower for chlorine (k = 0.7-5M(-1)s(-1)). Values of k correlated with initial SUVA values of NOM (UVA measured at 254 nm divided by DOC). Based upon UV/VIS and solid-state (13)C-NMR spectroscopy, chlorine addition to a NOM isolate resulted in significant oxidation of aromatic and ketone groups while bromine had significantly less change in spectra. Overall, the improved knowledge that bromine reacts faster and substitutes more efficiently than chlorine will be useful in developing strategies to control disinfection by-product formation during water treatment.

Evaluation of a microfluidic based cell culture platform with primary human hepatocytes for the prediction of hepatic clearance in human

Integral to the discovery of new pharmaceutical entities is the ability to predict in vivo pharmacokinetic parameters from early stage in vitro data generated prior to the onset of clinical testing. Within the pharmaceutical industry, a whole host of assay methods and mathematical models exist to predict the in vivo pharmacokinetic parameters of drug candidates. One of the most important pharmacokinetic properties of new drug candidates predicted from these methods and models is the hepatic clearance. Current methods, while useful, are still limited in their predictive efficacy. In order to address this issue, we have established a novel microfluidic in vitro culture system, the patented HmuREL device. The device comprises multiple compartments that are designed to be proportional to the physiological architectures and enhanced with the consideration of flow. Here we demonstrate the functionality of the liver-relevant chamber in the HmuREL device, and the feasibility of utilizing our system for predicting hepatic clearance. Cryopreserved human hepatocytes from a single donor were seeded within the HmuREL device to predict the in vivo hepatic clearance (CL(H)) of six marketed model compounds (carbamazepine, caffeine, timolol, sildenafil, imipramine, and buspirone). The intrinsic clearance rates from static culture controls, as well as clearance rates from the HmuREL device were subsequently compared to in vivo data available from the literature.

Colorectal tumors: an in vitro study of high-resolution MR imaging

To study the potential utility of magnetic resonance (MR) imaging in staging colorectal tumors, 15 resected colonic segments containing 17 elevated lesions were examined on a 1.5- or 1.9-T superconductive MR system. The whole intestinal wall was apparent as three or five layers on images obtained with a short repetition time (TR) and short echo time (TE) and as six or eight distinct layers, including the intestinal wall proper as well as an adherent mucus layer and an outer layer of pericolonic fat, on the long TR/TE images. In cases of colonic carcinoma, MR images correlated well with the pathologic findings, including the macroscopic growth pattern, depth of mural invasion, and the presence of foci of calcific tumor necrosis and pools of extracellular mucin (colloid). These features suggest that MR imaging may be valuable in the clinical evaluation of colorectal tumors.

Extra- and intracellular hydrogen ion-selective microelectrode based on neutral carriers with extended pH response range in acid media

A series of new neutral hydrogen ion carriers suitable for application in H+-selective microelectrodes is presented. One carrier (ETH 1907) proves to be superior to tridodecylamine currently very much in use. Microelectrodes based on ETH 1907 in an optimized membrane composition exhibit a linear dynamic response function from pH 2 to 9 extended into the acidic range, a response time less than or equal to 5 s, and a resistance of about 35 G omega for a tip diameter of about 1 micron. This makes the electrode suitable for measurements at normal physiological intracellular pH as well as in acid physiological media. Measurements using this microelectrode in proximal tubule cells of isolated perfused frog kidney are presented.

The release of an endogenous pyrogen from guinea pig leukocytes in vitro: a new model for investigating the role of lymphocytes in fevers induced by antigen in hosts with delayed hypersensitivity

Guinea pig periotoneal exudate (PE) cells incubated overnight in vitro with heat-killed Staphylococci released an endogenous pyrogen (EP) that could be assayed by intravenous injection in rabbits. The febrile responses were linearly related to the dosage of EP over an eightfold range. PE cells derived from guinea pigs with delayed hypersensitivity (DH) to bovine gamma globulin (BGG), also released EP when incubated with antigen in vitro. This reaction was specific and did not occur withe PE cells from normal or complete Freund's adjuvant-sensitized guinea pigs. Studies indicated that monos and/or polymorphonuclear leukocytes rather than lymphocytes were the source of EP. However, when incubated with BGG and sufficient dosages of BGG-sensitized lymphocytes, normal PE cells released EP over a 42 h period. These results suggest that antigen stimulates specifically sensitized lymphocytes to release an agent (perhaps a lymphokine) that activates phagocytic cells to release EP. This model offers unique advantages for investigating in vitro the role of the lymphocyte in antigen-induced fever in DH as well as the relationship of this lymphocyte-induced activity to other known biologic activities mediated by antigen stimulated lymphocytes.

2007 San Diego wildfires and asthmatics

CONTEXT

This case series reports the changes in the respiratory health of eight asthmatic subjects and the relationship with air quality associated with the October 2007 firestorm in San Diego County of California.

CASE PRESENTATION

Participants were eight subjects with asthma enrolled in Asthma Clinical Research Network (ACRN) (NIH# U10-HL074218) studies at the University of California San Diego (UCSD), School of Medicine, who had study data collected immediately prior, during and 1 month after the 5-day firestorm in San Diego County. Air quality deteriorated to an extreme average of 71.5 mg/m(3) small particulate matter less than 2.5 μm (PM(2.5)) during the firestorm. Respiratory health data included morning and evening peak expiratory flow rates (PEFR), morning and evening Forced Expiratory Volume in one second (FEV(1)), rescue medication usage, and sputum eosinophils. Morning and evening PEFR and FEV(1) rates remained stable. The two subjects tested during the fires had elevated eosinophil counts and rescue medication usage was increased in five of the eight subjects.

DISCUSSION

Pulmonary function test values were stable during the wildfires for all eight subjects but there was a statistically significant increase in rescue medication usage during the wildfires that correlated with PM(2.5) values. The two subjects tested during the fires showed increases in sputum eosinophil counts consistent with increased airways inflammation.

RELEVANCE

These findings suggest that poor air quality associated with wildfires resulted in an increase in airways inflammation in these asthmatic subjects, but pulmonary function tests remained stable, possibly due to increased rescue medication usage. This is especially pertinent as there is an increase in incidence of wildfires this decade.

Sequence analysis and expression of a cDNA clone encoding a 98-kDa allergen in Dermatophagoides farinae

BACKGROUND

The important dust mite allergens identified to date are of molecular weights ranging from 14 to 60 kDa. Our previous protein study indicated that the 98-kDa native paramyosin in Dermatophagoides farinae mite showed IgE reactivity with 82% of the mite-sensitive asthmatic patients suggesting that it is a novel major mite allergen. This study described the isolation and characterization of the cDNA clone encoding the 98-kDa mite allergen.

METHODS

A Dermatophagoides farinae cDNA library was constructed in lambda ZAPII vector and the library was immunoscreened with a monoclonal antibody 642. The cDNA insert was sub-cloned into M13 sequencing vector for single-stranded sequencing. The whole cDNA insert was expressed in pGEX-2T Escherichia coli expression system as a fusion protein with GST. The allergenicity of the recombinant peptides was tested by skin tests and IgE immunoassay. The IgE and IgG immunoassays were performed with sera from 20 mite-allergic patients.

RESULTS

The cDNA clone Df642 was 2134 bp long, coding for a polypeptide of 711 amino acid residues. Protein sequence analysis and alignment confirmed that the deduced polypeptide is a mite paramyosin which is truncated slightly at the N- and C-terminuses. In vivo skin tests and in vitro IgE-binding study showed that 62% (13/21) and 50% (10/20) of the mite-sensitive asthmatic patients reacted positively with the recombinant Dermatophagoides farinae paramyosin, respectively.

CONCLUSION

The study indicated that 98-kDa mite paramyosin is an important allergen.

CT features of presacral mass: an unusual focus of extramedullary hematopoiesis

A case of beta-thalassemia with an unusual focus of extramedullary hematopoiesis is reported. The presacral area was involved producing a significant mass effect on the rectum.

Primary prevention of coronary heart disease. What has WOSCOPS told us and what questions remain? West Of Scotland Coronary Prevention Study

Coronary heart disease remains the major cause of death and morbidity in developed countries. As a consequence, its prevention constitutes a significant public health challenge. In recent times, our understanding of this disease process has expanded and many of the factors that influence its expression have been elucidated. In addition, a number of trials of diet and lipid-lowering drugs have been performed in an effort to tackle this problem. These studies demonstrate that when lipid levels are favourably altered, cardiovascular events are reduced without adverse effect. The rate at which event outcomes diverge between treated and untreated patients depends on the degree of atherosclerosis manifestation prior to treatment and the aggressiveness of the lipid altering strategy. Nonetheless, to date, the residual risk of cardiovascular events is still unacceptably high despite even the most potent lipid-lowering treatments used in these trials. In order to minimise the risk of future events, earlier intervention and a greater change in LDL and HDL cholesterol levels are needed in conjunction with other risk factor modifications.

CT demonstration of giant choledochal cysts in adults

The initial diagnosis for three adult patients with giant choledochal cysts was confused because of the enormous size of the cysts. Jaundice in association with marked upper gastrointestinal displacement was the dominant feature in two of our cases. Intrahepatic ductal dilatation is common when choledochal cysts present in the adult. The malignant potential of choledochal cysts is discussed.

The Conundrum of Volume Status Assessment: Revisiting Current and Future Tools Available for Physicians at the Bedside

Assessment of patients’ volume status at the bedside is a very important clinical skill that physicians need in many clinical scenarios. Hypovolemia with hypotension and tissue under-perfusion are usually more alarming to physicians, but hypervolemia is also associated with poor outcomes, making euvolemia a crucial goal in clinical practice. Nevertheless, the assessment of volume status can be challenging, especially in the absence of a gold standard test that is reliable and easily accessible to assist with clinical decision-making. Physicians need to have a broad knowledge of the individual non-invasive clinical tools available for them at the bedside to evaluate volume status. In this review, we will discuss the strengths and limitations of the traditional tools, which include careful history taking, physical examination, and basic laboratory tests, and also include the relatively new tool of point-of-care ultrasound.

Implications of prospective payment under DRGs for hospital marketing

The authors analyze the hospital marketing implications of Medicare's prospective payment system under DRGs. They take an appropriately broad view of marketing and consider related impacts on culture, structure, and management, in addition to the traditional marketing mix. The article serves to present in one place the ideas and discussions on the subject from a wide and disparate literature. The aim throughout is to identify those marketing responses warranting recommendation. The recommendations are assembled in a concluding section. Though many of the ideas are not new, they have yet to be widely adopted by hospitals. Hence they represent untapped marketing opportunities attributable to the advent of the DRG system. The authors conclude with suggestions for future research.

The use of magnetic resonance imaging in the evaluation of bone and soft-tissue tumors

We believe that MR imaging should follow plain films in the imaging analysis of soft-tissue tumors and bone tumors suspected of malignancy. MR imaging is primarily useful in tumor staging, although it may aid in diagnosis and the detection of recurrent or residual disease. Gd-DTPA and MR spectroscopy are currently being evaluated in many medical centers; their utility in the work-up and management of tumors of bone and soft tissue has yet to be determined.

Evidence for a sodium-induced activation of central neurogenic mechanisms in one-kidney, one-clip renal hypertensive rats

The mechanisms sustaining high blood pressure in conscious one-kidney, one-clip Goldblatt rats were evaluated with the use of SK&F 64139, a phenylethanolamine N-methyltransferase inhibitor capable of crossing the blood-brain barrier and of captopril, an angiotensin converting enzyme inhibitor. The rats were studied 3 weeks after left renal artery clipping and contralateral nephrectomy. During the developmental phase of hypertension, two groups of rats were maintained on a regular salt (RNa) intake, whereas two other groups were given a low salt (LNa) diet. On the day of the experiment, the base-line mean blood pressure measured in the LNa rats (177.4 +/- 5.2 mm Hg, mean +/- S.E., n = 15) was similar to that measured in the RNa rats (178.7 +/- 5.4 mm Hg, n = 16). SK&F 64139 (12.5 mg p.o.) induced a significantly more pronounced (P less than .001) blood pressure decrease in the RNa rats (-25.6 +/- 3.6 mm Hg, n = 8) than in the LNa rats (-4.3 +/- 3.3 mm Hg, n = 7) during a 90-min observation period. On the other hand, captopril (10 mg p.o.) normalized blood pressure in LNa rats (n = 8), but produced only a 13.4 mm Hg blood pressure drop in RNa rats (n = 8). RNa rats treated with SK&F 64139 were found to have decreased phenylethanolamine N-methyltransferase activity by an average 80% in selected brain stem nuclei when compared with nontreated rats. No significant difference in plasma catecholamine levels was found between the RNa and LNa rats. These results suggest that, in this experimental model of hypertension, the sodium ion might increase the model of hypertension, the sodium ion might increase the vasoconstrictor contribution of the sympathetic system via a centrally mediated neurogenic mechanism while at the same time it decreases the renin-dependency of the high blood pressure.