The use of the Rx spin label in orientation measurement on proteins, by EPR.

The bipedal spin label Rx is more restricted in its conformation and dynamics than its monopodal counterpart R1. To systematically investigate the utility of the Rx label, we have attempted to comprehensively survey the attachment of Rx to protein secondary structures. We have examined the formation, structure and dynamics of the spin label in relation to the underlying protein in order to determine feasibility and optimum conditions for distance and orientation measurement by pulsed EPR. The labeled proteins have been studied using molecular dynamics, CW EPR, pulsed EPR distance measurement at X-band and orientation measurement at W-band. The utility of different modes and positions of attachment have been compared and contrasted.

Investigating public health impacts of deer in a protected drinking water supply watershed.

The World Health Organisation's (WHO) Water Safety Plans highlight the need for preventative risk management when managing water contamination risks. As part of this approach, a management framework incorporating multiple barriers is necessary and there is a need to validate those barriers through scientific evidence. This paper reports on a study undertaken to validate the effectiveness, in terms of pathogen numbers, of having protected watersheds. The study aimed to determine if the deer population in a protected watershed carried Cryptosporidium and whether or not it was human infectious. Deer faecal samples were collected from the protected watersheds over a 12 month period and analysed using a new method, developed as part of this project, for genotyping Cryptosporidium. Early results showed the presence of Cryptosporidium, but following a refinement in the method no human infectious Cryptosporidium was detected. The results give some confidence that having protected watersheds is an effective barrier against pathogen contamination. They do not, however, imply that continued monitoring and management of the deer should cease. To maintain compliance with the Water Safety Plans, continual validation of barrier effectiveness is required.

Properties of a plasma membrane-associated cathepsin B-like cysteine proteinase in metastatic B16 melanoma variants.

Activities of a cathepsin B-like cysteine proteinase have previously been observed to correlate with the malignancy of several animal and human tumors. Plasma membrane fractions of some of these tumors have been found to be enriched in cathepsin B-like activity. We have determined the subcellular distribution of this enzyme and three additional lysosomal hydrolases (cathepsin H, beta-hexosaminidase, and beta-glucuronidase) in normal murine liver and six metastatic variants of the B16 melanoma. The tissues were fractionated initially by differential centrifugation followed by Percoll density gradient centrifugation of the light mitochondrial fraction. Two fractions were obtained: an L-2 fraction enriched in all four lysosomal hydrolases; and an L-1 fraction enriched in a marker enzyme for the plasma membrane. Cathepsin B-like and beta-hexosaminidase activities, but not the other hydrolase activities, were also found to be enriched in the L-1 fractions of the metastatic B16 tumors. We explored the nature of the association of the cathepsin B-like activity with the plasma membrane using fractions from the spontaneously metastatic B16 amelanotic melanoma. Activity could not be dissociated from the plasma membrane fraction by washing with a physiological salt solution suggesting that it was not adsorbed to this fraction nonspecifically, nor could it be displaced by mannose 6-phosphate or other sugars which compete for binding to the known lysosomal receptors. High salt concentrations, low concentrations of the mild detergent saponin, mild acidification, or phosphatidylinositol-specific phospholipase C did not elute the cathepsin B-like activity. However, activity was eluted by exposure to 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate, a detergent used in the purification of integral membrane proteins. The B16 amelanotic melanoma plasma membrane-associated cathepsin B-like activity had a slightly higher pH optimum and was resistant to inactivation by neutral pH and to inhibition by three low molecular weight inhibitors of cysteine proteinases. The Ki values for inhibition by leupeptin and stefin A were 20-fold higher. The presence of a cathepsin B-like cysteine proteinase at the surface of metastatic tumor cells, particularly in a form which can retain activity at physiological pH and retain activity in the presence of extracellular proteinase inhibitors, may contribute to the focal dissolution of the extracellular matrix observed at sites of contact with invading tumor cells.

The importance of the Lewis base in lithium mediated metallation and bond cleavage reaction of allyl amines and allyl phosphines.

Metallation of two analogous N- and P-allyl molecules Ph2NCH2CHCH2 and Ph2PCH2CHCH2 with nBuLi have shown contrasting reactivities based on the choice of Lewis donor. With metallation of the alpha carbon atom was achieved regardless of the Lewis donor used while in comparison metallation of showed an unexpected donor denticity dependence with P-C bond clevage induced with the tri-dentate PMDETA. Complementary DFT and solution studies rationalise this outcome.

A prospective randomized trial of prevention measures in patients at high risk for contrast nephropathy: results of the P.R.I.N.C.E. Study. Prevention of Radiocontrast Induced Nephropathy Clinical Evaluation.

OBJECTIVES: This study was done to test the hypothesis that a forced diuresis with maintenance of intravascular volume after contrast exposure would reduce the rate of contrast-induced renal injury. BACKGROUND: We have previously shown a graded relationship with the degree of postprocedure renal failure and the probability of in-hospital death in patients undergoing percutaneous coronary intervention. Earlier studies of singular prevention strategies (atrial natriuretic factor, loop diuretics, dopamine, mannitol) have shown no clear benefit across a spectrum of patients at risk. METHODS: A prospective, randomized, controlled, single-blind trial was conducted where 98 participants were randomized to forced diuresis with intravenous crystalloid, furosemide, mannitol (if pulmonary capillary wedge pressure <20 mm Hg), and low-dose dopamine (n = 43) versus intravenous crystalloid and matching placebos (n = 55). RESULTS: The groups were similar with respect to baseline serum creatinine (2.44+/-0.80 and 2.55+/-0.91 mg/dl), age, weight, diabetic status, left ventricular function, degree of prehydration, contrast volume and ionicity, and extent of peripheral vascular disease. The forced diuresis resulted in higher urine flow rate (163.26+/-54.47 vs. 122.57+/-54.27 ml/h) over the 24 h after contrast exposure (p = 0.001). Two participants in the experimental arm versus five in the control arm required dialysis, with all seven cases having measured flow rates <145 ml/h in the 24 h after the procedure. The mean individual change in serum creatinine at 48 h, the primary end point, was 0.48+/-0.86 versus 0.51+/-0.87, in the experimental and control arms, respectively, p = 0.87. There were no differences in the rates of renal failure across six definitions of renal failure by intent-to-treat analysis. However, in all participants combined, the rise in serum creatinine was related to the degree of induced diuresis after controlling for baseline renal function, r = -0.36, p = 0.005. The rates of renal failure in those with urine flow rates greater than 150 ml/h in the postprocedure period were significantly lower, 8/37 (21.6%) versus 28/61 (45.9%), p = 0.03. CONCLUSIONS: Forced diuresis with intravenous crystalloid, furosemide, and mannitol if hemodynamics permit, beginning at the start of angiography provides a modest benefit against contrast-induced nephropathy provided a high urine flow rate can be achieved.

Functional evidence of persistent airway obstruction in rats following a two-hour inhalation exposure to methyl isocyanate.

Pulmonary function was assessed in male, F344 rats 1,2,4,7, and 13 weeks after a single 2-hr exposure to 0, 3, 10, or 30 ppm methyl isocyanate. No significant changes were observed in the rats exposed to 3 ppm through 13 weeks. Diffusing capacity (DLco), quasistatic lung compliance, and homogeneity of ventilation, as determined by multibreath nitrogen washout, were depressed in the rats exposed to 10 and 30 ppm by 1 week after exposure. None of the rats exposed to 30 ppm survived beyond 1 week. By 13 weeks, dramatic increases in lung volumes were observed in the rats exposed to 10 ppm, while DLco and lung compliance were only mildly affected. However, volume-specific DLco and compliance were depressed in the rats exposed to 10 ppm, suggesting that lung hyperinflation or other compensatory means of increasing lung size occurred in response to the methyl isocyanate-induced lung lesion. This group also exhibited increased expiratory times during tidal breathing and severely impaired distribution of ventilated air. Collectively, these results suggest the development and likely progression of a severe, obstructive airway lesion with associated gas trapping, and the existence of a pronounced concentration-response relationship between 3 and 10 ppm methyl isocyanate exposures.

7p deletion syndrome: an adult with mild manifestations.

Deletion of 7p results in a wide spectrum of congenital abnormalities and minor facial and hand anomalies, often including craniosynostosis. We report on the oldest recognized patient with this disorder, a 24-year-old woman with an interstitial deletion from p15.3-p21.2 or p21.3. The manifestations in this patient are milder than those of previously described patients, and include borderline mental retardation, short stature, minor facial anomalies, and several skeletal changes. The absence of craniosynostosis in this patient is noteworthy, given previous suggestions that there is a specific locus for this finding in the 7p region. Twelve cases of 7p deletion, in which the missing segment overlaps that of the current case, are reviewed. This case delineates a broader spectrum for patients with 7p deletion syndrome.

High-resolution dosimetry using radiochromic film and a document scanner.

A method of reading exposed radiochromic film is described which has significant advantages over conventional densitometry. The method employs a document scanner and associated software for imaging the film. The resulting images are easily analysed using standard software to yield high-resolution dose maps. A calibration was performed which relates scanner signal to dose, allowing for the determination of dose at any point on an exposed film. Results obtained using a broad-band densitometer are compared to those where the scanner has been used. The technique was used to measure the dose distribution around a COMS-type ophthalmic applicator.

Assessing the health implications of turbidity and suspended particles in protected catchments.

The supply of unfiltered disinfected drinking water from Melbourne's fully protected catchments means that the water-quality managers must ensure that the source water poses no public health risk. High turbidity is currently used as a surrogate of pathogens, and harvesting of water is based on its measurement. The work presented here summarises suspended particle and associated pathogen, microbial indicator and faecal biomarker concentrations collected to (a) quantify turbidity in an Australian water supply system and (b) assess the possibility of increasing water harvesting from selected tributaries. Pathogens and microbial indicators were present in low numbers in these source waters; increased turbidity during storm events was not associated with an increase in pathogen concentration. The results confirmed that protected catchments, along with good management, were effective barriers to pathogen contamination. Aesthetic issues still need to be addressed, but no measurable increase in microbiological risk was associated with storm-generated particles.

Sports fractures.

Fractures occur in athletes and dramatically influence performance during competitive and recreational activities. Fractures occur in athletes as the result of repetitive stress, acute sports-related trauma and trauma outside of athletics. The literature provides general guidelines for treatment as well as a variety of statistics on the epidemiology of fractures by sport and level of participation. Athletes are healthy and motivated patients, and have high expectations regarding their level of function. These qualities make them good surgical candidates. Although closed treatment methods are appropriate for most sports fractures, an aggressive approach to more complicated fractures employing current techniques may optimize their subsequent performance.

Case report: paraarticular soft-tissue osteoma of the hip.

A case of paraarticular soft-tissue osteoma of the hip is presented. The patient is a 30-year-old white male with a two year history of progressive left hip pain. Plain film and cross-sectional imaging in conjunction with pathologic correlation are used to make the diagnosis. The lesion lacks the typical zoning pattern of myositis ossificans, shows no direct communication with native bone, and is extraarticular in location as opposed to synovial osteochondromatosis. Soft tissue osteomas most commonly occur around the knee, the foot, and the ankle. Soft tissue osteomas are rare tumors and this case is unusual in that it occurs around the hip.

Aposematism in Archips cerasivoranus not linked to the sequestration of host-derived cyanide.

This study addressed the question of how caterpillars of Archips cerasivoranus feeding upon Prunus virginiana cope with the cyanogenic compounds of their food. Analysis by ion chromatography showed that young and aged leaves of P. virginiana consumed by the caterpillars during spring have hydrogen cyanide potentials (HCN-ps) of 2,473 +/- 130 ppm and 1,058 +/- 98 ppm, respectively. Although less than 3% of the cyanide released as the caterpillars feed escapes into the atmosphere, the larva's bright-yellow aposematic coloration and conspicuous activity can not be attributed to the sequestration of cyanide. Only six of 25 samples of the caterpillars' defensive regurgitants collected from 12 field colonies contained cyanide (17.6 +/- 6.54 ppm), less than 5% of the quantity previously reported to occur in the regurgitant of the tent caterpillar M. americanum. Only seven of 13 caterpillars assayed had detectable quantities of cyanide in their bodies (3.9 +/- 0.9 ppm). The fecal pellets that encase the cocoon contained no cyanide, nor did the frass that litters the leaf shelters. The small quantities of cyanide that occur in the caterpillar compared to the HCN-p of ingested plant material appear attributable to paced bouts of feeding and the maintenance of a highly alkaline foregut that inhibits cyanogenesis.

Does sunlight cause premature aging of the crystalline lens?

Premature onset of presbyopia may be an early sign of cataractous lenticular changes. For many years ultraviolet radiation (UVR) has been suspected as a major factor in the degradation of the crystalline lens. Controlled laboratory studies have demonstrated that UVR does cause opacities that closely resemble those naturally occurring in the aging process. Is it true that environmental UVR is also the prime contributor in the deleterious lenticular changes that may begin with premature presbyopia, as has been postulated? This review examines the evidence supporting this and other suggested causes of early presbyopia, including genetics, nutrition, toxins, and environmental temperature. Of all factors reported to affect the onset of presbyopia, UVR has the most scientific support, but further research is necessary to conclusively establish this link.

Genotypic variation in carboxylation of tomatoes.

The gas exchange characteristics of 24 genotypes of Lycopersicon esculentum Mill. and one of L. minutum were measured with an infrared gas analyzer and dew point hygrometer in an open system. Net carbon exchange (NCE) and transpiration rate were measured at 50, 100, 150, and 300 mu1 1(-1) CO(2), and a regression of NCE versus internal lead [CO(2)] estimates was calculated. The slope of the regression curve at the CO(2) compensation point was used as the measure of carboxylation efficiency (CE). Significant genotypic differences for CE were obtained. Differences in CE did not appear to be due to differences in diffusive resistance defined as the sum of the boundary layer resistance (r(a)) and the stomatal plus cuticular resistance (r(1)). There was no correlation (r = -0.07) between (r(a) + r(1)) and CE. Within groups with nonsignificantly different means for (r(a) + r(1)) there were genotypes with extremes for CE.The zero CO(2) intercept has been used as an indication of photorespiration. Application of this method revealed a strong inverse relationship between CE and the intercept value, indicating either that photorespiration is related directly to CE or that this method is unreliable for estimating photorespiration. The fact that the variation in CE occurs at light saturation suggests that the observed differences in CE and rates of NCE are determined either by: (a) the concentration and/or kinetic properties of the photochemical reaction centers and associated electron transfer components as they affect the supply of NADPH and ATP and consequently the levels of Calvin cycle intermediates; or (b) the concentration and/or kinetic properties of ribulose 1,5-diphosphate carboxylase.

Meiosis in sesquidiploid hybrids of Lycopersicon esculentum and Solanum lycopersicoides.

We have synthesized diploid hybrids between Lycopersicon esculentum and Solanum lycopersicoides and have converted them to allotetraploids. Two sesquidiploids, having two complements of the former parent and one of the latter, have been obtained by backcrossing the former parent with the alloploid. In meiosis of the sesquidiploid the L. esculentum chromosomes exhibit strong preferential pairing, consistently forming 12 bivalents, whereas the S. lycopersicoides chromosomes remain unpaired. This chromosomal comportment conforms with expectations based on meiosis of the 2x and 4x hybrids. Condensation of the S. lycopersicoides univalents is retarded in early diakinesis but their development appears normal at later stages. Presumably as a consequence of the orderly behavior of the L. esculentum bivalents and consequent contribution to each gamete, fertility of the sesquidiploids is higher than in L. esculentum autotriploids. The normally strict self-incompatibility is somewhat relaxed in the sesquidiploids. Extra S. lycopersicoides chromosomes can be transmitted from the sesquidiploid as pistillate parent, and the aneuploid progeny are viable. Establishment of alien addition races and their utilization to transmit desired genes from S. lycopersicoides to L. esculentum are anticipated.

Residual oil fly ash amplifies allergic cytokines, airway responsiveness, and inflammation in mice.

Particulate matter (PM) air pollution may increase symptom severity in allergic asthmatics. To examine possible interaction, or greater than additive responses, between PM effects and allergic responses, an ovalbumin-sensitized and challenged (OVA) mouse model of allergic airways disease was utilized. After challenge, mice were intratracheally instilled with saline vehicle or 3 mg/kg (approximately 60 microg) residual oil fly ash (ROFA), a transition metal-rich emission source PM sample. Physiological and inflammatory responses were examined 1, 3, 8, and 15 d later. In response to intravenously administered methacholine, ROFA increased total respiratory system resistance and decreased compliance 1 d after exposure, whereas effects of OVA lasted at least 15 d after exposure. Significant interactions between OVA and ROFA were mainly observed 8 d after challenge and exposure, especially with respect to compliance. A strong interaction (p < 0.01) between OVA and ROFA exposure resulted in 8-fold (1 d) and 3-fold (3 d) increases in bronchoalveolar lavage (BAL) fluid eosinophil numbers. A similarly strong interaction (8-fold) was observed in BAL fluid interleukin-4 (IL-4) 1 d after challenge and exposure. Significant though less strong interactions were also found with respect to IL-4 and IL-5 by 3 d postchallenge/exposure. This study shows that allergen challenge and exposure to emission source particulate matter containing relatively high levels of transitions metals can interact to increase Th2 cytokine production, eosinophil recruitment, and airway hyperresponsiveness in previously sensitized mice.

Imaging features of avulsion injuries.

Avulsion injuries are common among participants in organized sports, especially among adolescent participants. Imaging features of both acute and chronic avulsion injuries of the pelvis, knee, ankle and foot, shoulder, and elbow were evaluated to help distinguish these injuries from more serious disease processes such as neoplasm and infection. At radiography, acute injuries (ie, those resulting from extreme, unbalanced, often eccentric muscular contractions) may be associated with avulsed bone fragments, whereas subacute injuries have an aggressive appearance that may include areas of mixed lysis and sclerosis. Chronic injuries (ie, those resulting from repetitive microtrauma or overuse) or old inactive injuries may be associated with a protuberant mass of bone and may bear a striking resemblance to a neoplastic or infectious process. Although not usually required, computed tomography is helpful in the diagnosis if radiographic findings are equivocal or if the injury is not in the acute phase. MR imaging is best suited for the evaluation of injuries to muscles, tendons, and ligaments. Recognition of characteristic imaging features and familiarity with musculotendinous anatomy will aid in accurate diagnosis of avulsion injuries.