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Biomedical subjects

A Cass

Publications and source records attributed to A Cass.

At least 19 recordsLinked to original sources
PubMed2005

Chronic kidney disease in the general population.

End-stage kidney disease (ESKD), defined as the need for dialysis, receipt of a transplant, or death from chronic kidney failure, generally affects fewer than 1% of the population. However ESKD is the end result of chronic kidney disease (CKD), a widely prevalent but often silent condition with elevated risks of cardiovascular morbidity and mortality and a range of metabolic complications. A recently devised classification of CKD has facilitated prevalence estimates that reveal an "iceberg" of CKD in the community, of which dialysis and transplant patients are the tip. Hypertension, smoking, hypercholesterolemia, and obesity, currently among the World Health Organization's (WHO's) top 10 global health risks, are strongly associated with CKD. The factors, together with increasing diabetes prevalence and an aging population, will result in significant global increases in CKD and ESKD patients. Treatments now available effectively reduce the rate of progression of CKD and the extent of comorbid conditions and complications. The challenges are (1) to intervene effectively to reduce the excess burden of cardiovascular morbidity and mortality associated with CKD, (2) to identify those at greatest risk for ESKD and intervene effectively to prevent progression of early CKD, and (3) to ultimately introduce cost-effective primary prevention to reduce the overall burden of CKD. The vast majority of the global CKD burden will be in developing countries, and policy responses must be both practical and sustainable in these settings.

Disease Progression↗
PubMed2004

Renal-related deaths in Australia 1997-1999.

BACKGROUND: Despite marked increases in cases of treated end-stage renal disease in Australia, little is known about renal disease mortality. AIMS: To quantify the contribution of renal diseases to mortality in Australia and to explore the relationship between renal disease and other common diseases as causes of death. METHODS: Data from the Australian Bureau of Statistics on underlying and associated causes of death (based on death certificates) were examined for deaths occurring in 1997-1999 and registered by the end of 1999. Causes of death were coded according to the International Classification of Diseases, 10th Revision (ICD-10). Several causes outside the ICD-10 chapter on diseases of the genito-urinary system (e.g. diabetic renal disease, hypertensive renal disease and congenital malformations of the kidney) were included as renal. RESULTS: Of 378,832 recorded deaths, renal disease was coded as the underlying cause for 7888 (2.1%) and as an associated cause for an additional 28,012 (7.4%). Almost all renal deaths (98.4%) had at least one other cause of death recorded on the death certificate. CONCLUSIONS: The contribution of renal disease to Australian mortality has been underestimated because of historical reliance on a single (underlying) cause of death. Deaths involving renal disease usually occur in the context of multiple coexisting chronic and/or acute conditions.

Australia↗
PubMed2001

Regional variation in the incidence of end-stage renal disease in Indigenous Australians.

OBJECTIVE: To evaluate regional variation in the incidence of end-stage renal disease (ESRD) in Indigenous Australians, and to examine the proximity to ESRD treatment facilities of Indigenous patients. DESIGN: Secondary data review, with collection of primary data regarding patients' place of residence before beginning ESRD treatment. PARTICIPANTS: Indigenous ESRD patients who commenced treatment in Australia during 1993-1998. METHODS: We obtained data from the Australian and New Zealand Dialysis and Transplant Registry regarding 719 Indigenous patients who started ESRD treatment between 1 January 1993 and 31 December 1998. We obtained primary data from the treating renal units to determine the place of residence before beginning renal replacement therapy. We calculated the average annual incidence of ESRD for each of the 36 Aboriginal and Torres Strait Islander Commission regions using population estimates based on the 1996 Census, and calculated standardised incidence ratios with 95% confidence intervals for each region. We compared the number of cases with the treatment facilities available in each region. MAIN OUTCOME MEASURE: Regional standardised ESRD incidence for Indigenous Australians referenced to the total resident population of Australia. RESULTS: Standardised ESRD incidence among Indigenous Australians is highest in remote regions, where it is up to 30 times the national incidence for all Australians. In urban regions the standardised incidence is much lower, but remains significantly higher than the national incidence. Forty-eight per cent of Indigenous ESRD patients come from regions without dialysis or transplant facilities and 16.3% from regions with only satellite dialysis facilities. CONCLUSIONS: There is marked regional variation in the incidence of ESRD among Indigenous Australians. Because of the location of treatment centres, there is inequitable access to ESRD treatment services for a significant proportion of Indigenous patients.

Australia↗
PubMed2001

Social disadvantage and variation in the incidence of end-stage renal disease in Australian capital cities.

OBJECTIVE: To evaluate variation in the incidence of end-stage renal disease (ESRD) within Australian capital cities. To explore the relation between the incidence of ESRD and socioeconomic disadvantage. METHODS: We obtained data from the Australian and New Zealand Dialysis and Transplant Registry (ANZDATA) regarding 5,013 patients from capital cities who started ESRD treatment between 1 April 1993 and 31 December 1998. We used the postcode at the start of treatment to calculate the average annual incidence of ESRD for each of 51 capital city regions using 1996 Census counts based on place of usual residence. We calculated standardised incidence ratios with 95% confidence intervals for each region. The standardised incidence ratios were examined in relation to the SEIFA Index of Relative Socio-economic Disadvantage (IRSD), derived from the 1996 Census. Low IRSD values indicate more disadvantaged areas. RESULTS: There is significant variation in the standardised incidence of ESRD within capital cities. There was a significant correlation (r=-0.41, p=0.003) between the standardised incidence ratio for ESRD and the SEIFA IRSD. CONCLUSIONS AND IMPLICATIONS: Capital city areas that are more disadvantaged have a higher incidence of ESRD. Socioeconomic factors may be important determinants of the risk of developing ESRD.

Australia↗
PubMed1999

End-stage renal disease in aboriginals in New South Wales: a very different picture to the Northern Territory.

OBJECTIVES: To compare the incidence of end-stage renal disease (ESRD) among Aboriginals in New South Wales with the incidence among Aboriginals in the Northern Territory, and to compare the patterns of ESRD among Aboriginals and non-Aboriginals in NSW. DESIGN: Secondary data analysis of information from unpublished and published Australia and New Zealand Dialysis and Transplant Registry reports. MAIN OUTCOME MEASURES: Average annual incidence of ESRD (persons per million); form of renal replacement therapy; mortality at 31 March 1998; patient and graft survival one and five years after transplant. RESULTS: Each year in NSW, 5-17 new Aboriginal patients are treated for ESRD. There was no increase in the average annual incidence of ESRD among NSW Aboriginals (118 per million in 1988-1989 and 111 per million in 1996-1997), whereas incidence in the NT increased from 255 per million to 800 per million. In NSW, ESRD was attributed to diabetes in 32% of Aboriginal patients, compared with 13% of non-Aboriginal patients (P < 0.001). In NSW, Aboriginal patients were younger and more likely to be female, a pattern similar to that in the NT. The outcome of ESRD treatment is not significantly different between Aboriginals and non-Aboriginals in NSW. CONCLUSION: There is a different pattern of incidence of ESRD and of outcomes with treatment among Aboriginals in NSW compared with those in the NT. A possible explanation is that the lower incidence in NSW reflects less profound socioeconomic disadvantage and better access to primary and specialist care.

Adolescent↗
PubMed1999

Anti-RNA polymerase III antibodies in the diagnosis of scleroderma renal crisis sine scleroderma.

We describe the use of antibodies to RNA polymerase III in the diagnosis of scleroderma in 2 patients who presented with renal crisis without other clinical features of the condition. Both presented with accelerated hypertension, rapidly progressive acute renal failure, microangiopathic hemolytic anemia, and thrombocytopenia. One patient developed digital infarcts in the course of his initial illness. Neither showed evidence of skin thickening at presentation. Nailfold capillaroscopy was normal in one patient and showed capillary dropout in the other. Renal biopsy showed findings consistent with thrombotic microangiopathy and both had anti-RNA polymerase III antibodies.

Autoantibodies↗
PubMed1984

Psychrometric Field Measurement of Water Potential Changes following Leaf Excision.

In situ measurement of sudden leaf water potential changes has not been performed under field conditions. A laboratory investigation involving the measurement of leaf water potential prior to and 2 to 200 minutes after excision of citrus leaves (Citrus jambhiri) showed good linear correlation (r = 0.99) between in situ leaf psychrometer and Scholander pressure chamber measurements. Following this, a field investigation was conducted which involved psychrometric measurement prior to petiole excision and 1 minute after excision. Simultaneous pressure chamber measurements were performed on neighboring leaves prior to the time of excision and then on the psychrometer leaf about 2 minutes after excision. These data indicate that within the first 2 minutes after excision, psychrometer and pressure chamber measurements were linearly correlated (r = 0.97). Under high evaporative demand conditions, the rate of water potential decrease was between 250 and 700 kilopascals in the first minute after excision. These results show that the thermocouple psychrometer can be used as a dynamic and nondestructive field technique for monitoring leaf water potential.

Journal Article↗
PubMed1983

In situ field measurement of leaf water potential using thermocouple psychrometers.

Thermocouple psychrometers are the only instruments which can measure the in situ water potential of intact leaves, and which can possibly be used to monitor leaf water potential. Unfortunately, their usefulness is limited by a number of difficulties, among them fluctuating temperatures and temperature gradients within the psychrometer, sealing of the psychrometer chamber to the leaf, shading of the leaf by the psychrometer, and resistance to water vapor diffusion by the cuticle when the stomates are closed. Using Citrus jambhiri, we have tested several psychrometer design and operational modifications and showed that in situ psychrometric measurements compared favorably with simultaneous Scholander pressure chamber measurements on neighboring leaves when the latter were corrected for the osmotic potential.

Journal Article↗
PubMed1982

An accurate temperature correction model for thermocouple hygrometers.

Numerous water relation studies have used thermocouple hygrometers routinely. However, the accurate temperature correction of hygrometer calibration curve slopes seems to have been largely neglected in both psychrometric and dewpoint techniques.In the case of thermocouple psychrometers, two temperature correction models are proposed, each based on measurement of the thermojunction radius and calculation of the theoretical voltage sensitivity to changes in water potential. The first model relies on calibration at a single temperature and the second at two temperatures. Both these models were more accurate than the temperature correction models currently in use for four psychrometers calibrated over a range of temperatures (15-38 degrees C). The model based on calibration at two temperatures is superior to that based on only one calibration.The model proposed for dewpoint hygrometers is similar to that for psychrometers. It is based on the theoretical voltage sensitivity to changes in water potential. Comparison with empirical data from three dewpoint hygrometers calibrated at four different temperatures indicates that these instruments need only be calibrated at, e.g. 25 degrees C, if the calibration slopes are corrected for temperature.

Journal Article↗
PubMed1981

Prenatal diagnosis of fetal urinary tract abnormalities by ultrasound.

The prenatal detection of renal enlargement and sonolucent "cystic" lesions in 4 fetal abdomens by ultrasound is described. These were later proved to be congenital urinary tract anomalies. Only one of the other 4,628 mothers who had ultrasound gave birth to a child with a congenital urinary tract anomaly that was missed, and 1 fetus was falsely diagnosed as having a congenital urinary tract anomaly based on the ultrasound. Obstruction in the developing urinary tract is associated with renal dysplasia and insufficiency. More experience and improved ultrasonography may enable an accurate diagnosis of urinary tract obstruction; and early relief of the obstruction may be a possible method of management to minimize the renal damage.

Abnormalities, Multiple↗
PubMed1979

Necrotizing infection of scrotum.

Necrotizing infection of the scrotum (Fournier gangrene) rapidly spreads to adjacent skin with fever and toxemia and is life-threatening. Subcutaneous gas and a foul-smelling wet discharge from the skin are usually present. The infection is not cured with antibiotic therapy alone and requires immediate extensive debridement of all necrotic tissue. Repeated debridement each several days under general anesthesia is necessary until healthy granulation is present in the wound. Reconstruction with skin flaps or skin grafts shortens hospitalization and prevents the dense scar tissue and immobility of the tests that can occur with spontaneous epithelization.

Adult↗
PubMed1979

Chloride transport by self-exchange and by KCl salt diffusion in gramicidin-treated red blood cells.

The permeability of gramicidin-treated human red blood cell membranes to K+ and Cl- has been measured at normal ionic strength (1) by tracer exchange at steady-state distribution of salt, and (2) by net transport of salt in the presence of a salt concentration gradient. Under both conditions KCl was the only inorganic salt in cells and medium. In the studies of self-exchanges the electrical driving force on the ions was zero. Calculaton of permeability coefficients from net salt transport was simplified because the experiment was designed as a special case of the Nerst-Planck diffusion regime, i.e. the single salt case. Gramicidin altered the cell membranes from being anion to become cation selective. Gramicidin increased the potassium exchange without affecting the chloride exchange measurably. The chloride exchange showed saturation kinetics as does chloride exchange in normal cells. The net transport of KCl in the presence of a constant concentration gradient increased to a constant value with increasing gramicidin concentration. At high gramicidin concentrations (0 degree C, pH 7.2) the "chloride permeability coefficient" calculated from tracer exchange (1.9 x 10(-6) cm/s) was 290 times the chloride permeability coefficient calculated from net salt transport (0.65 x 10(-8) cm/s). The latter value corresponds to a chloride conductance of 4.2 x 10(-6) ohm-1 cm-2. The chloride permeability coefficient was 2.1 x 10(-6) cm/s at 25 degrees C (pH 6.8) indicating a value of 3 for the Q25. It appears that normal red cells are anion selective in the sense that anion permeability exceeds cation permeability with a factor of more than a hundred between 0 degrees C and body temperature. The anion exchange, i.e. the Hamburger shift, is a tightly coupled transport process which is several orders of magnitude faster than anion transport by salt diffusion.

Biological Transport↗
PubMed1978

Acute electrical stimulation for urinary incontinence.

Acute or maximal electric stimulation of the pelvic floor muscles has been used in incontinent patients who are suitable candidates for electrical stimulation, but unwilling or unable to use the anal plug electrodes. Seventeen of 20 patients had relief or improvement of their incontinence. However 5 of these 17 patients had a relapse of symptoms on follow-up, requiring a repeat treatment with acute or maximal electrical stimulation.

Electric Stimulation Therapy↗
PubMed1977

Electrical stimulation of the rectal ampulla causing reflex voiding.

Electrical stimulation of the rectal ampulla resulted in a desire to void and defecate in 11 patients with an intact nervous system. There was a contraction of the detrusor and the rectal ampulla with relaxation of the anal sphincter. Electrical stimulation of the rectal ampulla and anal sphincter has clinical applications in patients with incontinence of, or inability to empty, the lower urinary tract or fecal system.

Anal Canal↗
PubMed1976

Effect of phloretin on the permeability of thin lipid membranes.

Phloretin dramatically increases cation conductances and decreases anion conductances of membranes treated with ion carriers (nonactin, valinomycin, carbonyl-cyanide-m-chlorophenylhydrazone [CCCP], and Hg(C6F5)2) or lipophilic ions (tetraphenylarsonium [tphAs+] and tetraphenylborate [TPhB-]). For example, on phosphatidylethanolamine membranes, 10(-4) M phloretin increases K+ -nonactin and TPhAs+ conductances and decreases CCCP- and TPhB- conductances 10(3)-fold; on lecithin: cholesterol membranes, it increases K+-nonactin conductance 10(5)-fold and decreases CCCP- conductance 10(3)-fold. Similar effects are obtained with p- and m-nitrophenol at 10(-2) M. These effects are produced by the un-ionized form of phloretin and the nitrophenols. We believe that phloretin, which possesses a large dipole moment, adsorbs and orients at the membrane surface to introduce a dipole potential of opposite polarity to the preexisting positive one, thus increasing the partition coefficient of cations into the membrane interior and decreasing the partition coefficient of anions. (Phloretin may also increase the fluidity of cholesterol-containing membranes; this is manifested by its two- to three-fold increase in nonelectrolyte permeability and its asymmetrical effect on cation and anion conductances in cholesterol-containing membranes.) It is possible that pholoretin's inhibition of chloride, urea, and glucose transport in biological membranes results from the effects of these intense intrafacial dipole fields on the translocator(s) of these molecules.

Anti-Bacterial Agents↗