Evaluating TROPOMI and MODIS performance to capture the dynamic of air pollution in São Paulo state: A case study during the COVID-19 outbreak.

Atmospheric pollutant data retrieved through satellite sensors are continually used to assess changes in air quality in the lower atmosphere. During the COVID-19 pandemic, several studies started to use satellite measurements to evaluate changes in air quality in many different regions worldwide. However, although satellite data is continuously validated, it is known that its accuracy may vary between monitored areas, requiring regionalized quality assessments. Thus, this study aimed to evaluate whether satellites could measure changes in the air quality of the state of São Paulo, Brazil, during the COVID-19 outbreak; and to verify the relationship between satellite-based data [Tropospheric NO2 column density and Aerosol Optical Depth (AOD)] and ground-based concentrations [NO2 and particulate material (PM; coarse: PM10 and fine: PM2.5)]. For this purpose, tropospheric NO2 obtained from the TROPOMI sensor and AOD retrieved from MODIS sensor data by using the Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm were compared with concentrations obtained from 50 automatic ground monitoring stations. The results showed low correlations between PM and AOD. For PM10, most stations showed correlations lower than 0.2, which were not significant. The results for PM2.5 were similar, but some stations showed good correlations for specific periods (before or during the COVID-19 outbreak). Satellite-based Tropospheric NO2 proved to be a good predictor for NO2 concentrations at ground level. Considering all stations with NO2 measurements, correlations >0.6 were observed, reaching 0.8 for specific stations and periods. In general, it was observed that regions with a more industrialized profile had the best correlations, in contrast with rural areas. In addition, it was observed about 57% reductions in tropospheric NO2 throughout the state of São Paulo during the COVID-19 outbreak. Variations in air pollutants were linked to the region economic vocation, since there were reductions in industrialized areas (at least 50% of the industrialized areas showed >20% decrease in NO2) and increases in areas with farming and livestock characteristics (about 70% of those areas showed increase in NO2). Our results demonstrate that Tropospheric NO2 column densities can serve as good predictors of NO2 concentrations at ground level. For MAIAC-AOD, a weak relationship was observed, requiring the evaluation of other possible predictors to describe the relationship with PM. Thus, it is concluded that regionalized assessment of satellite data accuracy is essential for assertive estimates on a regional/local level. Good quality information retrieved at specific polluted areas does not assure a worldwide use of remote sensor data.

Predictive value of performance validity testing and symptom validity testing in psychoeducational assessment.

Using archival data from 2463 psychoeducational assessments of postsecondary students we investigated whether failure on either symptom or performance validity tests (SVTs or PVTs) was associated with score differences on various cognitive, achievement, or executive functioning performance measures or on symptom report measures related to mental health or attention complaints. In total, 14.6% of students failed one or more PVT, 33.6% failed one or more SVT, and 41.6% failed at least one validity test. Individuals who failed SVTs tended to have the highest levels of self-reported symptoms relative to other groups but did not score worse on performance-based psychological tests. Those who failed PVTs scored worse on performance-based tests relative to other groups. Failure on at least one PVT and one SVT resulted in both performance and self-reported symptoms suggestive of greater impairment compared with those who passed all validity measures. Findings also highlight the need for domain-specific SVTs; failing ADHD SVTs was associated only with extreme reports of ADHD and executive functioning symptoms while failing mental health SVTs related only to extreme reports of mental health complaints. Results support using at least one PVT and one SVT in psychoeducational assessments to aid in diagnostic certainty, given the frequency of non-credible presentation in this population of postsecondary students.

The impact of depression and anxiety on speed of academic performance and retrieval fluency in postsecondary students.

Objective: This study evaluated the functional effects of severe mental health symptoms on speed of academic performance to assist clinicians and educators in determining whether extra time accommodations are evidence-based for students with such diagnoses. Method: Using archival data from 1476 post-secondary students, we examined the performance of students with existing mental health diagnoses who were also reporting extremely high levels of symptoms. Their performance on timed academic achievement and cognitive processing measures was compared with performance of students with learning disabilities, Attention Deficit Hyperactivity Disorder, and clinical controls. Students failing stand-alone performance validity and/or symptom validity measures were excluded from this investigation. Results: Students diagnosed with anxiety and/or depression did not differ from clinical controls on any timed performance measure, typically performing academic tasks within a normal amount of time. By contrast, those with reading disabilities were typically the slowest on all academic tasks. Conclusion: Across the range of timed tests, students with mental health diagnoses did not show functional impairments in tests with a speed component. As such, they would not typically require increased time to perform speeded academic tasks, but they might require alternative accommodations in their post-secondary programmes in order to participate equally.

How mobility restrictions policy and atmospheric conditions impacted air quality in the State of São Paulo during the COVID-19 outbreak.

Mobility restrictions are among actions to prevent the spread of the COVID-19 pandemic and have been pointed as reasons for improving air quality, especially in large cities. However, it is crucial to assess the impact of atmospheric conditions on air quality and air pollutant dispersion in the face of the potential variability of all sources. In this study, the impact of mobility restrictions on the air quality was analyzed for the most populous Brazilian State, São Paulo, severely impacted by COVID-19. Ground-based air quality data (PM10, PM2.5, CO, SO2, NOx, NO2, NO, and O3) were used from 50 automatic air quality monitoring stations to evaluate the changes in concentrations before (January 01 - March 25) and during the partial quarantine (March 16 - June 30). Rainfall, fires, and daily cell phone mobility data were also used as supplementary information to the analyses. The Mann-Whitney U test was used to assess the heterogeneity of the air quality data during and before mobility restrictions. In general, the results demonstrated no substantial improvements in air quality for most of the pollutants when comparing before and during restrictions periods. Besides, when the analyzed period of 2020 is compared with the year 2019, there is no significant air quality improvement in the São Paulo State. However, special attention should be given to the Metropolitan Area of São Paulo (MASP), due to the vast population residing in this area and exposed to air pollution. The region reached an average decrease of 29% in CO, 28% in NOx, 40% in NO, 19% in SO2, 15% in PM2.5, and 8% in PM10 concentrations during the mobility restrictions period compared to the same period in 2019. The only pollutant that showed an increase in concentration was ozone, with a 20% increase compared to 2019 during the mobility restrictions period. Before the mobility restrictions period, the region reached an average decrease of 30% in CO, 39% in NOx, 63% in NO, 12% in SO2, 23% in PM2.5, 18% in PM10, and 16% in O3 concentrations when compared to the same period in 2019. On the other hand, Cubatão, a highly industrialized area, showed statistically significant increases above 20% for most monitored pollutants in both periods of 2020 compared to 2019. This study reinforces that the main driving force of pollutant concentration variability is the dynamics of the atmosphere at its various time scales. An abnormal rainy season, with above average rainfall before the restrictions and below average after it, generated a scenario in which the probable significant reductions in emissions did not substantially affect the concentration of pollutants.

The effect of acetazolamide, amiloride, bumetanide and SITS on secretion of fluid and electrolytes by the parotid gland of common wombats, Vombatus ursinus.

Mechanisms of saliva formation by wombat parotid glands were investigated in anaesthetized wombats at two levels of cholinergically-stimulated flow viz. mid-range (30-40% maximum flow) and maximum flow using ion-transport and carbonic-anhydrase inhibitors. Bumetanide (0.005-0.1 mmol l-1 carotid plasma) progressively reduced mid-range flow by 52 ± 3.4% (mean ± SEM). Concurrently, saliva [Cl] decreased, [Na] and [HCO3] increased but HCO3 excretion was unaltered. Salivary flow during high-rate cholinergic stimulation was 31 ± 1.1% of the pre-bumetanide maximum. During mid-range stimulation, SITS (0.075 mmol l-1) was without effect whereas 0.75 mmol l-1 stimulated transient increases in fluid output. The higher SITS concentration caused no alterations to flow or electrolyte concentrations during maximal stimulation. Carotid plasma [amiloride] (0.05 mmol l-1) caused immediate falls in flow rate of 20-30% followed by progressive recovery over 25 min to levels above pre-amiloride flow rates despite plasma [amiloride] increasing tenfold. Concurrently, salivary [Na] and [Cl] rose to equal plasma concentrations and [K] fell by 50% indicating blockade of acinar Na/H exchangers and luminal Na channels in the ducts. Increased salivary osmolarity caused the flow recovery. Saliva flow during maximum cholinergic stimulation was reduced by 38-46%. The depression of flow was interpreted as resulting from competition between amiloride and acetylcholine for access to the muscarinic receptors. Plasma [acetazolamide] (0.35-2.5 mmol l-1) did not alter saliva outflow during mid-range or maximum flow regimes whereas salivary [Cl] increased and [HCO3] decreased consistent with reduced anion exchange resulting from inhibition of carbonic anhydrase. Combined with bumetanide, acetazolamide (1.5 mmol l-1) reduced flow by an additional 18-22% relative to bumetanide alone thereby demonstrating that acinar HCO3 synthesis supported a limited proportion of saliva formation and that some HCO3 secretion was independent of carbonic anhydrase activity.

First UK trial of Xenex PX-UV, an automated ultraviolet room decontamination device in a clinical haematology and bone marrow transplantation unit.

BACKGROUND: There is growing interest in the use of no-touch automated room decontamination devices within healthcare settings. Xenex PX-UV is an automated room disinfection device using pulsed ultraviolet (UV) C radiation with a short cycle time. AIM: To investigate the microbiological efficacy of this device when deployed for terminal decontamination of isolation rooms within a clinical haematology unit. METHODS: The device was deployed in isolation rooms in a clinical haematology unit. Contact plates were applied to common touch points to determine aerobic total colony counts (TCCs) and samples collected using Polywipe™ sponges for detection of vancomycin-resistant enterococci (VRE). FINDINGS: The device was easy to transport, easy to use, and it disinfected rooms rapidly. There was a 76% reduction in the TCCs following manual cleaning, with an additional 14% reduction following UV disinfection, resulting in an overall reduction of 90% in TCCs. There was a 38% reduction in the number of sites where VRE was detected, from 26 of 80 sites following manual cleaning to 16 of 80 sites with additional UV disinfection. CONCLUSIONS: The Xenex PX-UV device can offer a simple and rapid additional decontamination step for terminal disinfection of patient rooms. However, the microbiological efficacy against VRE was somewhat limited.

Outbreak of invasive group A streptococcus infection: contaminated patient curtains and cross-infection on an ear, nose and throat ward.

BACKGROUND: Outbreaks of group A streptococcus (GAS) infections may occur in healthcare settings and have been documented in surgical, obstetrics and gynaecology, and burns units. The environment may serve as a reservoir and facilitate transmission via contaminated equipment. AIM: To describe the investigation and control of an outbreak of healthcare-associated GAS infection on an ear, nose and throat (ENT) ward in a tertiary referral centre. METHODS: Two patients with laryngeal cancer developed invasive GAS infection (bacteraemia) with associated tracheostomy wound cellulitis within a 48 h period. The outbreak team undertook an investigation involving a retrospective review of GAS cases, prospective case finding, healthcare worker screening and sampling of patient curtains. Immediate control measures included source isolation, a thorough rolling clean with a chlorine-based disinfectant and hydrogen peroxide decontamination of patient equipment. FINDINGS: Prospective patient screening identified one additional patient with carriage of GAS from a tracheostomy wound swab. Staff screening identified one healthcare worker who acquired GAS during the outbreak and who subsequently developed pharyngitis. Environmental sampling demonstrated that 10 out of 34 patient curtains on the ward were contaminated with GAS and all isolates were typed as emm-1. CONCLUSION: This is the first outbreak report to demonstrate patient curtains as potential source for GAS cross-transmission, with implications in relation to hand hygiene and frequency of laundering. Based on this report we recommend that during an outbreak of GAS infection all patient curtains should be changed as part of the enhanced decontamination procedures.

Response of the parotid gland of red kangaroos, Macropus rufus, to phenylephrine stimulation.

Intracarotid infusions of l-phenylephrine at 1.0 or 10 nmol kg(-1) min(-1) were accompanied by increases in salivary amylase activity, protein, potassium, magnesium and chloride relative to cholinergically-stimulated saliva. Intravenous infusions of phenylephrine at the same dose rates had a lesser effect on salivary composition particularly protein. Propranolol administered with phenylephrine via the carotid artery, at an antagonist/agonist ratio of 10:1, was much more effective in blocking the phenylephrine-induced changes in salivary composition than equimolar infusion of phentolamine with phenylephrine. It was concluded that alpha(1)-adrenoreceptors were not present in functionally significant numbers in the gland and that the effect of phenylephrine on the kangaroo parotid was mediated by beta-adrenoreceptors. As the phenylephrine dose rates in the kangaroos were comparable with those used to determine alpha-adrenergic responses of eutherian salivary glands and as phentolamine appeared to have minor beta-sympathomimetic activity, at least one subtype of beta-adrenoreceptors in macropods may not be identical to its eutherian counterpart.

Effect of adrenergic antagonists during phenylephrine stimulation of the mandibular gland of red kangaroos, Macropus rufus.

Intracarotid infusions of l-phenylephrine at 1.0 nmol.kg(-1).min(-1) or(.)10 nmol.kg(-1).min(-1) were accompanied by increases in salivary protein, urea, magnesium and bicarbonate, and by decreases in osmolality, hydrogen ion activity, sodium, potassium and chloride relative to cholinergically stimulated saliva. Intravenous infusions of phenylephrine at the same dose rates had much less effect on salivary composition with the differences between the routes of administration being greatest for the higher dose rate. Propranolol administered with phenylephrine via the carotid artery, at an antagonist:agonist ratio of 10:1, was much more effective in blocking the phenylephrine-induced changes in salivary composition than equimolar infusion of phentolamine with phenylephrine. Simultaneous intracarotid infusions of either a beta(1)-antagonist (CGP20712A) or a beta(2)-antagonist (ICI118551) with phenylephrine showed that ICI118551 was more potent than CGP20712A at preventing the changes in salivary composition associated with phenylephrine administration. It was concluded that alpha(1)-adrenoreceptors were not present in functionally significant numbers in the gland and that the effect of phenylephrine on the kangaroo mandibular was mediated by beta-adrenoreceptors predominantly of the beta(2)-subtype. As the phenylephrine dose rates in the kangaroos were comparable with those used to determine alpha-adrenergic responses of eutherian salivary glands and as both propranolol and phentolamine appeared to have minor beta-sympathomimetic activity, at least one subtype of beta-adrenoreceptors in macropods may not be identical to its eutherian counterpart.

Salivary secretion during selective beta-adrenoreceptor stimulation and blockade in the parotid gland of red kangaroos, Macropus rufus.

Intracarotid infusions of noradrenaline (0.3 nmol.kg(-1) x min(-1)) stimulated salivary fluid secretion and caused increases in salivary concentrations of protein, potassium. magnesium. chloride and phosphate, and decreases in bicarbonate. These effects of intracarotid noradrenaline were not reduced by simultaneous intracarotid infusion of phentolamine (3.0 nmol.kg(-1) x min(-1)) but were significantly greater than the responses accompanying intravenous noradrenaline infusion. Concomitant administration of the beta-antagonist, CGP20712A, were much more effective in blocking the noradrenaline-induced changes in salivary composition than equimolar infusions of the beta2-antagonist, ICI118551, thereby confirming the presence of beta1-adrenoreceptors. Intracarotid infusion of salbutamol at 0.6 nmol x kg(-1) x min(-1) and 6.0 nmol x kg(-1) x min(-1) caused increasing but qualitatively similar changes in salivary composition to intracarotid noradrenaline but was less effective than noradrenaline in augmenting salivary protein release. Equimolar intravenous infusions of salbutamol and noradrenaline were equally potent in altering salivary electrolyte concentrations but salbutamol by this route had less effect on protein release and fluid secretion. Concurrent intravenous and intracarotid infusions of beta1-(CGP) and beta2-(ICI) antagonists with intracarotid salbutamol showed that the beta2-antagonist was more potent than the beta1-antagonist by the intracarotid route thereby demonstrating the presence of glandular beta2-receptors and eliminating the possibility that the response to salbutamol was due totally by reflex increases in general sympathetic tone triggered by lowered blood pressure. It was concluded that the kangaroo parotid has functional beta1- and beta2-adrenoreceptor subtypes in endpieces whereas the data provide little support for either adrenoreceptor subtype being present in the excurrent duct system.

Who cares for medicaid-enrolled children with chronic conditions?

OBJECTIVE: To estimate generalist, pediatric subspecialist, and any subspecialist use by Medicaid-enrolled children with chronic conditions and to determine the correlates of use. METHODS: We analyzed Medicaid claims data collected from 1989 to 1992 from 4 states for 57 328 children and adolescents with 11 chronic conditions. We calculated annual rates of generalist, subspecialist, and pediatric subspecialist use. We used logistic regression to determine the association of demographics, urban residence, and case-mix (Adjusted Clinical Groups) with the use of relevant pediatric and any subspecialist care. RESULTS: Most children with chronic conditions had visits to generalists (range per condition: 78%-90% for children with Supplemental Security Income [SSI] and 85%-94% for children without SSI) during the year studied. Fewer children visited any relevant subspecialists (24%-59% for children with SSI and 13%-56% for children without SSI) or relevant pediatric subspecialists (10%-53% for children with SSI and 3%-37% for children without SSI). In general, children who were more likely to use pediatric subspecialists were younger, lived in urban areas, were white (only significant for non-SSI children), and had higher Adjusted Clinical Groups scores. Use of any subspecialists followed a similar pattern except that urban residence is statistically significant only for children with SSI and the youngest age group does not differ from the oldest age group for children without SSI. CONCLUSIONS: Children who had chronic conditions and were enrolled in Medicaid received a majority of their care from generalist physicians. For most conditions, a majority of children did not receive any relevant subspecialty care during the year and many of these children did not receive care form providers with pediatric-specific training.

Social influences on health-risk behaviors among minority middle school students.

PURPOSE: To determine whether parent social influences are associated with health-risk behaviors more than peer social influences among young minority adolescents. METHODS: We conducted a cross-sectional survey of seventh-grade students in a public urban magnet middle school using a survey instrument adapted from the Centers for Disease Control and Prevention Youth Risk Behavior Survey. The sample consisted of all seventh-grade students in the school, and the survey was part of a needs assessment for a school-based health education program. We measured four health-risk behaviors: use of (a) tobacco, (b) alcohol, (c) onset of sexual activity, and (d) marijuana use; and five social influences: (a) parent disapproval of health-risk behaviors, (b) parent modeling of health-risk behaviors, (c) parent monitoring of health-risks, (d) peer disapproval of health risks, and (e) peer modeling of health-risk behaviors. The analyses included measures of the prevalence of health-risk behaviors, bivariate analyses to evaluate relationships between health-risk behaviors and social influences, and regressions analyses to determine the independent associations of the social influences with the four health-risk behaviors. RESULTS: Twenty percent of respondents reported using tobacco, over 50% used alcohol in the past year, 13.3% were sexually active, and 12% reported marijuana use. Parent influences were associated with differences in alcohol use, whereas peer influences were associated with differences in all measured health-risk behaviors: tobacco and alcohol use, sexual activity, and marijuana use. Regression analyses demonstrated that peer social influences were the only measures independently associated with abstinence from tobacco (p < .05), alcohol (p < .01), sexual activity (p < .05), and marijuana use (p < .05). In all analyses, peers emerged as the most consistent social influence on health-risk behavior. CONCLUSION: This study suggests peers and peer group behavior may be better predictors of adolescent health-risk behaviors than parental social influences among young adolescents.

Traumatic hemorrhage of occult pheochromocytoma: a case report and review of the literature.

Pheochromocytoma usually presents with gradual onset and mild to moderate symptoms, but may present acutely with severe symptoms. Hemorrhage into pheochromocytoma is a rare cause of acute presentation that is often devastating to patients. We describe the case of a 34-year-old woman with hemorrhage into a previously undiscovered pheochromocytoma following a fall on a patch of ice. This is the first reported case of hemorrhagic pheochromocytoma associated with traumatic injury. Despite removal of the tumor within 18 hours of presentation, the patient suffered severe complications of massive catecholamine excess, including shock, cardiomyopathy, and adult respiratory distress syndrome. Animal studies have shown that early treatment with alpha blockers can prevent some, if not all of these complications. Proper management of hemorrhagic pheochromocytoma should include a high index of suspicion with early diagnosis and treatment with alpha blockers and surgical resection of the tumor when the patient is stable enough to tolerate the procedure.

Blockade of isoprenaline-induced fluid and protein secretion by the mandibular glands of the red kangaroo, Macropus rufus, with selective antagonists.

Selective and non-selective beta-adrenoceptor antagonists were used to block the increases in fluid and protein secretion caused by sympathomimetic stimulation of the mandibular gland of red kangaroos during intracarotid infusion of isoprenaline. Atenolol or ICI118551 at antagonist:agonist ratios up to 300:1 caused increasing but incomplete blockade of fluid secretion and protein release. Both selective antagonists had equal potency and both antagonists were more effective at blocking protein release than at blocking fluid secretion. Consequently, the mechanisms underpinning fluid secretion are more sensitive to beta-sympathomimetic stimulation than those causing protein release. Propranolol at antagonist:agonist ratios of 300:1 was more potent than the selective antagonists, almost totally blocking the increases in fluid secretion and protein release. The data are consistent with the acini of the kangaroo mandibular gland having both beta(1)- and beta(2)-adrenoceptors and with the increased fluid secretion and protein release by isoprenaline being mediated by both receptor subtypes.

A single source of health care: does it affect health experiences for inner-city children?

This study was designed to determine whether having a single source of health care affects the health experiences of inner-city children. Seventy-five women were interviewed about the health experiences of their preschool-aged children (range 10-58 months) and were asked about utilization, emergency room use, preventive care, delays in care, and availability of a provider for the child's various medical needs. While most (94.7 percent) of the mothers identified a regular source of care for their child's preventive care, 74.7 percent named the same source for their child's sick care. There were no differences in most measures between mothers with a single source of care and those with multiple sources. However, those with a single source of care reported feeling their providers were more available (p < 0.05). Thus, naming a single source of health care may not be a useful indicator of better health experiences for inner-city children.

Effect of beta-antagonists on isoprenaline-induced secretion of fluid, amylase and protein by the parotid gland of the red kangaroo, Macropus rufus.

Selective and non-selective beta-adrenoceptor antagonists were used to block the increases in fluid, protein and amylase secretion caused by sympathomimetic stimulation of the parotid gland of red kangaroos during intracarotid infusion of isoprenaline. ICI118551 at antagonist/agonist ratios up to 300:1 caused increasing but incomplete blockade of fluid secretion, and protein/amylase release. Atenolol at antagonist/agonist ratios up to 300:1 was only marginally more potent than ICI118551 at blocking the fluid, protein and amylase responses. Propranolol at antagonist/agonist ratios of 30:1 was as effective at blocking fluid and protein secretion as the highest ratios of either atenolol or ICI118551. Simultaneous administration of atenolol (30:1) with ICI118551 (30:1) was not as potent as propranolol (30:1). Thus, the beta-adrenoceptor/s in the acini of the kangaroo parotid gland appear to have antagonist-binding affinities atypical of those found for eutherian tissues. The data are consistent with the gland possessing either a single anomalous beta-adrenoceptor or functional beta(2)-receptors in addition to the beta(1)-receptors which are characteristic of eutherian salivary glands.

Selective stimulation and blockade of beta-adrenergic receptors in the mandibular gland of the red kangaroo, Macropus rufus.

Intracarotid infusions of noradrenaline (0.15 nmol x kg(-1) x min(-1)) either alone or accompanied by phentolamine (1.5 nmol x kg(-1) x min(-1)) caused similar-sized increases in salivary protein, magnesium and bicarbonate, and decreases in osmolality, sodium, potassium and chloride whereas intravenous noradrenaline stimulated much smaller responses. Concurrent infusions of the beta1-antagonist, CGP20712A, blocked these noradrenaline-induced changes in salivary composition more effectively than equimolar infusions of the beta2-antagonist, ICI118551, thereby confirming the presence of beta1-adrenoceptors. Intracarotid infusion of salbutamol at 0.15, 0.3 and 1.5 nmol x kg(-1) x min(-1) caused increasing but qualitatively similar changes in salivary composition, sodium excepted, to intracarotid noradrenaline with 0.3 nmol being most similar quantitatively. Intravenous infusion of salbutamol caused larger changes in salivary composition than equimolar intravenous noradrenaline thereby indicating that the response to salbutamol may, in part, be mediated by reflex increases in general sympathetic tone triggered by lowered blood pressure. Eliminating this hypotensive effect by concurrent intravenous and intracarotid infusions of beta1-(CGP or atenolol) and beta2-(ICII18551) antagonists with intracarotid salbutamol showed that IC1118551 was more potent than the beta1-antagonists thereby demonstrating the presence of beta2-receptors. It was concluded that the kangaroo mandibular has functional beta1- and beta2-adrenoceptor subtypes in both endpieces and excurrent ducts and that the duct system has two populations of cells, each expressing one receptor subtype.

High-performance liquid chromatographic determination of paclitaxel in rat serum: application to a toxicokinetic study.

A simple and sensitive high-performance liquid chromatographic method is described for the determination of paclitaxel (Taxol) at 230 nm using a Nucleosil C18 (5 microm) column and a methanol-water (70:30, v/v) mobile phase following a single-step extraction from serum with dichloromethane. The assay was validated against the classical criteria and was applied to a toxicokinetic study in rats after one or five, one per week) intraperitoneal administrations of 16 mg/kg Taxol.

Enzyme activity in parotid and mandibular saliva from red kangaroos, Macropus rufus.

Parotid and mandibular saliva was obtained from red kangaroos by concurrent acetylcholine isoprenaline stimulation. Salivary proteins were separated by horizontal electrophoresis on either cellulose acetate or starch gels and assessed by specific staining techniques for 23 enzymes commonly found in mammalian tissues and body fluids. Parotid saliva was positive for acid phosphatase, alpha-amylase, carbonic anhydrase, glucose-6-phosphate dehydrogenase, sorbitol dehydrogenase and superoxide dismutase activities. Mandibular saliva was positive for alcohol dehydrogenase in addition to the above six enzymes. The kangaroo salivas lacked activity for alkaline phosphatase, beta-galactosidase and non-specific esterase which occur in saliva from some mammalian species.

Response of the parotid gland of the brushtail possum, Trichosurus vulpecula, to adrenergic stimulation.

Adrenergic stimulation of parotid secretion was investigated in anaesthetised brushtail possums to ascertain fluid secretion rates and salivary composition. Because neither alpha- nor beta-adrenergic stimulation evoked saliva output, infusion of the adrenergic agonists was superimposed on a pre-existing bethanechol-stimulated flow. Isoprenaline infusion (2.4 nmol min-1) increased salivary amylase activity, [protein]; [HCO3]; [PO4] and [Ca], and amylase/Ca and protein/Ca ratios; reduced [Cl]; [K] and osmolality; but did not alter H+ activity; [urea]; [Na]; [Mg]; amylase/protein or saliva/plasma urea ratios. These data are consistent with isoprenaline stimulating acinar secretion of protein, Ca and PO4 but not the ion transport necessary for primary fluid formation at the endpieces and modifying transport of monovalent ions in the excurrent ducts. Consequently, the possum parotid has beta-adrenergic receptors in both the endpieces and excurrent ducts. Phenylephrine infusions at 2.4 and 24 nmol min-1 were without effect whereas phenylephrine at 240 nmol min-1 caused changes in salivary composition which paralleled those for isoprenaline administration but were generally of lesser magnitude. Thus, the possum parotid has few or no alpha-adrenergic receptors and the salivary response elicited was the result of cross-reaction of phenylephrine with beta-adrenergic receptors.