published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

This work is a quantitative description of the renal excretion and the post-renal modification of ureteral urine from native (unanesthetized, uninfused, and normal hydropenic) desert quail, Lophortyx gambelii. The technique used in this study establishes the glomerular filtration rate (GFR), urine flow rate, and urinary excretion of water, sodium, potassium, and uric acid for desert quail in a relatively undisturbed state and in steady-state balance with regard to intake and output of water, sodium, and potassium. In contrast, conventional methods of determining GFR in birds include the use of anesthesia, cloacal or ureteral canulation, and infusion of fluids to introduce filtration markers (e.g. inulin) and to cause a diuresis (e.g. by using mannitol). In the present study, native desert quail had a urine flow rate of about 40 g/kg.day compared to over 500 g/kg.day for desert quail previously studied using conventional methods. Also in the present study, GFR was about 1.6 ml/kg.min which is about 25% lower than previously reported (2.1 ml/kg.min) for desert quail studied with conventional techniques. Renal absorption of the filtered loads of water, sodium and potassium also was determined in the present study. The fractions of the filtered loads reabsorbed by the renal tubules were: for water 98%, for sodium 99.4%, and for potassium 42%. These findings illustrate that renal reabsorption of these filtered substances is less complete in birds than in mammals where, in man for example, about 99% of the water and 99.8% of the sodium are normally reabsorbed. In addition, this study evaluates the role of the cloaca and lower intestines in changing the composition of the ureteral urine. Ureteral urine is modified in the cloaca and lower intestines of the desert quail before being excreted with the final droppings. This modification results in reabsorption of about 70% of the water and sodium and about 80% of the potassium in the ureteral urine. Thus for the desert quail, post-renal reabsorption of water and sodium from ureteral urine produced by the kidneys increases the total amounts of the filtered loads reabsorbed to 99% for water and 99.7% for sodium, which are nearly the same as seen for man. It is concluded that post-renal reabsorption of water and sodium is an important aspect of fluid and electrolyte balance in native desert quail. About 65% of the uric acid present in the ureteral urine was found to be degraded during its passage into the lower intestines. This is particularly significant because trapping of sodium and potassium occurs within the uric acid precipitates which form in bird urine. It was determined that about 20% of the sodium and 33% of the potassium in the ureteral urine are trapped within uric acid precipitates. Degradation of uric acid may increase the reabsorbable pools of these cations and facilitate their reabsorption by the tissues of the lower intestines. Since the intestinal ceca of birds contain large populations of uric acid-decomposing bacteria, and because other studies have suggested large amounts of water are reabsorbed in the ceca of birds, the role of the ceca in post-renal modification of urine was evaluated. The results are not conclusive. Cecaectomized (Cx) birds showed only a transitory increase in water loss when compared to sham operated (Sh) birds. No difference in uric acid excretion was seen between Cx or Sh birds. Thus, no obligatory role for the ceca in post-renal reabsorption of water and electrolytes, or in degradation of uric acid, was evident.

Background: The most commonly employed screening method for proteinuria is a semi- quantitative dipstick urinalysis, but it has been shown to be inaccurate in pregnancy. New developments in the assessment of proteinuria have included the use of urinary albumin measurements. The Clinitek Microalbumin Reagent Strip (Bayer Healthcare LLC, USA) is a semi-quantitative dipstick test. It is used to measure the spot urinary microalbumin to creatinine ratio that is read using the Clinitek 50 portable urine chemistry analyzer. Aims We embarked on a pilot study to validate the Clinitek 50 system by determining the accuracy of spot urinary microalbumin to creatinine ratio dipsticks and conventional visual dipsticks (Makromed) compared to the laboratory urinary microalbumin to creatinine ratio quantification to detect significant proteinuria in normotensive and hypertensive antenatal attendees. The accuracy of spot urinary microalbumin to creatinine ratio dipsticks and conventional visual dipsticks were then compared to a 24 hour urinary protein (gold standard) to detect significant proteinuria in hypertensive disorders of pregnancy. We then determined the role of proteinuria as assessed by the diagnostic accuracy of both the 24 hour urinary protein (gold standard) and the spot urinary microalbumin to creatinine ratio dipstick, in pregnancy outcomes of these participants. Methods This was a prospective study conducted at hospitals serving the Durban Metropolitan region in South Africa. To validate the urinary microalbumin to creatinine ratio dipstick, fifteen normotensive healthy pregnant women and 11 women with new onset hypertension in pregnancy were recruited .Each women had a spot midstream urine, which was assessed for proteinuria using a semi-quantitative visual dipstick (Makromed) and analysed using the semi-quantitative urinary microalbumin to creatinine ratio dipsticks (Clinitek® Microalbumin) read on the Clinitek® 50 urine chemistry analyser. A result of 1 + on visual dipsticks and a spot urinary microalbumin to creatinine ratio UAC of > 300mg/g (33.9mg/mmol) was considered as positive for significant proteinuria. The results were compared to the laboratory quantitative measurement of the urinary microalbumin to creatinine ratio. The study group comprised 163 women presenting with newly diagnosed hypertension during pregnancy after 20 weeks of gestation, being recruited from antenatal clinics. Each participant had a spot urine sample that was tested by trained midwives for proteinuria using a semi-quantitative visual dipstick (Makromed). Participants were admitted to the ward where a spot midstream urine sample was collected and analysed using the semi-quantitative urinary microalbumin to creatinine ratio dipsticks. A 24 hour quantitative urinary protein analysis was completed. The results of the urinary microalbumin to creatinine ratio dipsticks and conventional visual dipsticks were compared to the 24 hour urinary protein (gold standard) to detect significant proteinuria. A urinary microalbumin to creatinine ratio of < 300mg/g (nil and trace on visual urine dipsticks) was considered to be a negative result. A urinary microalbumin to creatinine ratio 300 mg/g (1+ to 4+ on visual urine dipsticks) was considered to be a positive result. Urinary protein 0.3 g/24 hours was considered significant proteinuria. The outcomes of pregnancy in 2 sub-categories viz. those with and without significant proteinuria were compared using the 24 hr urinary protein measurement. A secondary analysis of outcomes of pregnancy was performed by subcategorizing the participants according to the diagnostic accuracy of the urinary microalbumin to creatinine ratio dipsticks. In the 26 patients enrolled in the initial study , the visual dipstick had a sensitivity of 25% ( 95% CI [0.04-0.64] ) and specificity of 89% ( 95% CI [0.64 -0.98]).The urinary microalbumin to creatinine ratio dipsticks had a sensitivity of 88% ( 95% CI [0.47-0.99]), specificity of 89% (95% CI [0.64-0.98]), negative predictive value (NPV) of 94% (95% CI [0.69-1.00]) and positive predictive value (PPV) of 78% (95% CI [0.40-0.96]). In the 163 patients subsequently enrolled the visual dipstick had a sensitivity of 51 % ( 95% CI [0.41-0.61]) and specificity of 91% (95% CI [0.81-0.96]) .The PPV and NPV was 89 %( 95% CI [0.77-0.95]) and 58% (95% CI [0.48-0.67]) respectively. The urinary microalbumin to creatinine ratio dipsticks had a sensitivity of 63% (95% CI [0.52-0.72]) and specificity of 81 % (95% CI [0.70-0.89]). The PPV was 82% (95% CI [0.71-0.90]) and NPV was 62% (95% CI [0.51-0.71]). Our results show that in hypertensive pregnant women, significant proteinuria determined by the quantitative 24 hour urinary protein is associated with delivery at an earlier gestational age, increased induction of labour and lower birthweights compared to the non-proteinuric hypertensives (gestational hypertension). There is also a trend towards an increased maternal morbidity and perinatal mortality. When the groups were classified into pre-eclampsia and gestational hypertension using the diagnostic accuracy of the urinary microalbumin to creatinine ratio dipsticks, there were no differences in the clinical outcomes between the false negatives and true negatives except a trend towards a higher caesarean section rate in the false negatives. Conclusion The urinary microalbumin to creatinine ratio dipstick read on the Clinitek 50 system provides a semi – quantitative result of the urinary microalbumin to creatinine ratio that has good sensitivity and specificity. Furthermore, the urinary microalbumin to creatinine ratio dipstick has a good negative predictive value and a result of < 300mg/g rules out significant proteinuria and avoids unnecessary investigations in pregnancy. Both the visual dipstick (Makromed) and the urinary microalbumin to creatinine ratio dipstick read on the Clinitek 50 system are not accurate when compared to the total 24 hour urinary protein. Differences between the urinary microalbumin to creatinine ratio and 24 hour total urinary protein may be due to the variation in the albumin fraction of the total urinary protein of pre-eclampsia, technical problems with imprecision of the assay technique and clinical causes of false positives and negatives. The improved sensitivity of the automated urinary microalbumin to creatinine ratio dipstick over the visual dipstick suggests it may be a suitable substitute for the visual dipstick in clinical practice Hypertension in pregnancy associated with significant proteinuria is associated with greater adverse maternal and fetal outcome. Outcome of pregnancy is similar when a classification of gestational hypertension is made based either on the 24 hour urinary protein or the urinary microalbumin to creatinine ratio dipstick read on the Clinitek 50 system. The urinary microalbumin to creatinine ratio dipstick is a good screening test to rule out significant proteinuria. It has the potential to improve accuracy of screening for proteinuria and enhancing safety by preventing incorrect diagnosis and unnecessary investigation. Further research is required to determine its full impact and cost effectiveness in the clinical setting. / Thesis (M.Med.)-University of KwaZulu-Natal, 2008.

Appendix 7, (3 leaves) in pocket / Includes bibliography / 1 v. (various foliations) : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Clinical and Experimental Pharmacology, 1984

The importance of protein-induced hypercalciuria and the variables contributing to this effect were assessed in a survey of 150 men, 18-56 years of age. Each participant kept a five day dietary record and collected their total urinary output for the last three days of the five. Urinary calcium, magnesium, sulfate and nitrogen were determined on these samples. There was a significant correlation of r = .31 (p < .0001) between dietary protein and urinary calcium. Linear regression analysis (y = 1.22x + 98) revealed that the slope of the line representing this relationship was similar to that of well controlled experimental studies. Calcium intake did not appear to alter this relationship, as the correlation between dietary protein and urinary calcium changed only slightly when calcium intake was statistically controlled. Dietary protein and phosphorus were so interrelated r = .85 (p < .0001) that it was not possible to separate the effects of phosphorus from protein on urinary calcium. The correlation between urinary sulfate and calcium was r = .50 (p < .0001) and step-wise addition multiple regression analysis indicated that urinary sulfate was the best predictor of urinary calcium. Urinary magnesium was not affected by dietary protein or urinary sulfate. However, urinary magnesium and urinary nitrogen were correlated r = .43 (p < .0001) and urinary nitrogen was found to be the best predictor of urinary magnesium. Neither body weight and creatinine excretion nor the amount kilocalories consumed confounded any of the correlations. These results indicate that protein-induced hypercalciuria may be a real effect in this population and that urinary sulfate is the most important determinant of this effect. / M.S.

Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: This study focused on the development of an analytical method whereby creatinine, creatine and caffeine could be determined quantitatively. Urine is the preferred body fluid for the analysis of metabolites that the body excretes after administration of medicinal and illicit drugs. The detection of these metabolites depends on the volume of water the patient has drunk or, in criminal cases, the amount of water the suspect may deliberately add to their urine to dilute it. Creatinine, whose concentration in urine has been found to correlate with muscle mass, is chosen as an endogenous control substance against which the metabolite concentration is compared. While high performance liquid chromatography with ultraviolet detection (HPLC–UV) is commonly selected for the analysis, the quality of chromatography is affected by the fact that creatinine, being highly polar, is not retained in the reversed-phase columns. Furthermore, urine contains many polar substances that elute with the solvent front along with creatinine, thereby grossly affecting HPLC measurements. Hydrophilic interaction chromatography (HILIC) is a good alternative, although these methods generally require extensive sample preparation. Direct infusion electrospray ionization mass spectrometry (DI–ESI–MS) is ideally suited to highly polar compounds and was selected for this work. Pneumatically assisted ESI is preferred above the standard ionization method of atmospheric pressure chemical ionization (APCI) since pneumatically assisted ESI disperses the solution into ion-containing aerosol droplets which do not promote online conversion of creatinine to creatine. The objective of this study was to develop a simple and sensitive DI–ESI–MS method for the determination of various compounds in urine with creatinine as analytical reference compound and internal standard (IS). The analytical method development includes addition of 1-methyl-3-phenylpropylamine as a primary IS to standard solutions as well as to urine samples, followed by direct infusion of the sample into a mass spectrometer to determine the absolute concentrations of creatinine, creatine and caffeine. After appropriate instrument conditions were established, linear graphs of analyte-IS signal intensity ratios were obtained. The ratio of the concentration of the analyte (drug or metabolite) to that of creatinine (as IS) may be used to determine analyte concentration in artificial samples and/or urine. This method is not affected by change in fluid volume or adulteration of urine samples because the analyte-to-creatinine ratio remains unchanged. As part of this study, the developed DI–ESI–MS method was compared with an LC–UV–MS method developed for this purpose. / AFRIKAANSE OPSOMMING: Hierdie studie fokus op die ontwikkeling van ‘n analitiese metode waardeur kreatinien, kreatien en kaffeïen kwantitatief bepaal kan word. Uriene is die voorkeur liggaamsvloeistof vir die analise van metaboliete wat deur die liggaam, na administrasie van mediese en onwettige middels, uitgeskei word. Die deteksie van hierdie metaboliete hang van die volume water af wat die pasiënt gedrink het, of in strafbare gevalle, die hoeveelheid water wat verdagtes met opset by hul uriene gevoeg het ten einde dit te verdun. Daar is bevind dat die konsentrasie van kreatinien in uriene met spiermassa korreleer, derhalwe is kreatinien as ‘n interne kontrolemiddel gekies waarmee die metaboliet-konsentrasie vergelyk kan word. Hoë-druk vloeistofchromatografie met ultravioletdeteksie (HPLC–UV) word algemeen vir die analise van kreatinien ingespan, maar die gehalte van die chromatografie word deur die hoogs polêre aard van kreatinien beïnvloed en het swak retensie in omgekeerde-fasekolomme tot gevolg. Bowendien, uriene bevat groot hoeveelhede polêre middels wat saam met kreatinien in die oplosmiddelfront elueer en sodoende HPLC-bepalings uitermatig beïnvloed. Hidrofiliese interaksiechromatografie (HILIC) is ‘n goeie alternatief, ofskoon omvangryke monster-voorbereidings algemeen vereis word. Direkte inspuitelektrosproei-ionisasiemassaspektrometrie (DI–ESI–MS) is ideaal geskik vir hoogs polêre stowwe en is vir hierdie studie gekies. Pneumatiese hulp-ESI word bo die standaard ionisasie-metode van lugdruk chemiese ionisasie (APCI) verkies weens pneumatiese hulp-ESI se vermoë om die oplosmiddel in aërosoldruppels wat ione bevat, te versprei – sonder die aanlynomskakeling van kreatinien na kreatien. Die doel van hierdie studie was om ‘n eenvoudige en sensitiewe DI–ESI–MS-metode te ontwikkel wat verskeie stowwe in uriene kan bepaal deur kreatinien as analitiese verwysingsmiddel en interne standaard (IS) vir die opstelling van ‘n IS-kalibrasiekurwe te gebruik. Die analitiese metode-ontwikkeling sluit die gebruik van 1-metiel-3-fenielpropielamien as primêre IS in. Die IS word tot standaard oplossings en urienemonsters gevoeg, gevolg deur direkte inspuiting van die monster in ‘n massaspektrometer om die absolute konsentrasies van kreatinien, kreatien en kaffeïen te bepaal. Lineêre kurwes van die seinintensiteitsverhouding van analiet tot IS is verkry na gepaste instrumentkondisies vasgestel is. Die verhouding van konsentrasie van die analiet (middel of metaboliet) tot dié van kreatinien (as IS) mag gebruik word om die analietkonsentrasie in die standaard oplossings en/of urienemonster te bepaal. Die metode word nie deur veranderinge in die vloeistofvolume of verwatering van urienemonsters beïnvloed nie, weens die analiet-tot-kreatinienverhouding wat onveranderd bly. ‘n LC–UV–MS-metode is voorts ontwikkel om die ontwikkelde DI–ESI–MS-metode se data te vergelyk.

Xiao, Yajie. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 156-190). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

In this series of work, we examined the role of measuring cytokine mRNA expression in the urinary sediments for the assessment of SLE disease activity. The Th-1/Th-2 imbalance observed in patients with active lupus nephritis supports its relevance in pathogenesis. Our results also suggest that urinary T-BET-to-GATA-3 expression ratio may predict lupus flare. The measurement of mRNA expression in the urinary sediment may provide valuable information for the assessment and risk stratification of SLE patients. (Abstract shortened by UMI.) / In this series of work, we investigated (i) the pattern of cytokine gene expression in the urinary sediment of lupus patients, (ii) the relation between the gene expression profile in the urinary sediment and the clinical and histological disease activity of lupus patients; and (iii) the application of this non-invasive method on the assessment and monitoring of SLE disease activity. / Systemic lupus erythematosus (SLE) is a relapsing autoimmune disease with clinical manifestations that affect multiple organ systems. Lupus nephritis (LN) is recognized as one of the most severe organ involvement in SLE and affects half of the lupus patients. LN is characterized by intra-renal lymphocyte activation and inflammation. Since most of the cytokines exert their effects in a paracrine fashion, measuring their expression at the site of pathology should be of biologic relevance. Although kidney biopsy is widely used to determine the histology and severity of LN, this invasive procedure has its own risk and is not practical for serial monitoring. We hypothesize that measurement of messenger RNA (mRNA) expression in the urinary sediment may provide a non-invasive means to assess the disease activity of lupus patients. / Chan Wing Yan. / "August 2005." / Adviser: Cheuk Chun Szeto. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3692. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 302-333). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.

Foram desenvolvidos métodos de determinação de urina e trítio em urina. Para o urânio foi adaptada a técnica de análise por fluorimetria em meio sólido. O limite de sensibilidade foi de 5. 10-4&#181;g U/0,1 ml e o erro foi de cerca de 10% para concentrações em torno de 0,05 &#181;g U/0,1 ml. Foi padronizado para o trítio o método de análise por cintilação em meio líquido. O método determina quantidades de trítio até pelo menos 8,10-3&#181;Ci/ml e o erro foi de cerca de 4% para concentrações de trítio em torno de 0,34 &#181;Ci/l. Depois de adaptadas, as técnicas foram aplicadas a amostras de urinas de trabalhadores expostos a compostos de urânio ou trítio com a finalidade de verificar possível contaminação interna por estes radioisótopos. / Abstract not available.