Thresholds of serum calcium oxalate supersaturation in relation to renal function in patients with or without primary hyperoxaluria

2012 ◽  
Vol 302 (6) ◽  
pp. F688-F693 ◽  
Author(s):  
John Knight ◽  
Ross P. Holmes ◽  
Scott D. Cramer ◽  
Tatsuya Takayama ◽  
Eduardo Salido

Primary hyperoxaluria type 1 (PH1) and type 2 (PH2) are rare genetic diseases that result from deficiencies in glyoxylate metabolism. The increased oxalate synthesis that occurs can lead to kidney stone formation, deposition of calcium oxalate in the kidney and other tissues, and renal failure. Hydroxyproline (Hyp) catabolism, which occurs mainly in the liver and kidney, is a prominent source of glyoxylate and could account for a significant portion of the oxalate produced in PH. To determine the sensitivity of mouse models of PH1 and PH2 to Hyp-derived oxalate, animals were fed diets containing 1% Hyp. Urinary excretions of glycolate and oxalate were used to monitor Hyp catabolism and the kidneys were examined to assess pathological changes. Both strains of knockout (KO) mice excreted more oxalate than wild-type (WT) animals with Hyp feeding. After 4 wk of Hyp feeding, all mice deficient in glyoxylate reductase/hydroxypyruvate reductase (GRHPR KO) developed severe nephrocalcinosis in contrast to animals deficient in alanine-glyoxylate aminotransferase (AGXT KO) where nephrocalcinosis was milder and with a lower frequency. Plasma cystatin C measurements over 4-wk Hyp feeding indicated no significant loss of renal function in WT and AGXT KO animals, and significant and severe loss of renal function in GRHPR KO animals after 2 and 4 wk, respectively. These data suggest that GRHPR activity may be vital in the kidney for limiting the conversion of Hyp-derived glyoxylate to oxalate. As Hyp catabolism may make a major contribution to the oxalate produced in PH patients, Hyp feeding in these mouse models should be useful in understanding the mechanisms associated with calcium oxalate deposition in the kidney.


BJPsych Open ◽  
2021 ◽  
Vol 7 (S1) ◽  
pp. S109-S110
Author(s):  
Leia Valentine ◽  
John Cannon ◽  
Siobhan Marmion ◽  
Michelle Corcoran ◽  
Marguerite Cryan ◽  
...  

AimsTo compare Lithium prescribing practices in a Psychiatry of Old Age (POA) Service in the North-West of Ireland among adults aged 65 years and over with best practice guidelines.MethodReview of the literature informed development of audit standards for Lithium prescribing. These included National Institute for Clinical Excellent (NICE) 2014 guidelines, The British National Formulary (2019) and Maudsley Prescribing Guidelines (2018). Data were collected retrospectively, using an audit-specific data collection tool, from clinical files of POA team caseload, aged 65 years or more and prescribed Lithium over the past one year.ResultAt the time of the audit in February 2020, 18 patients were prescribed lithium, 67% female, average age 74.6 years. Of those prescribed Lithium; 50% (n = 9) had a depression diagnosis, 44% (n = 8) had bipolar affective disorder (BPAD) and 6% (n = 1) had schizoaffective disorder.78% (n = 14) of patients were on track to meet, or had already met, the NICE standard of 3-monthly serum lithium level. Lithium levels were checked on average 4.5 times in past one year, average lithium level was 0.61mmol/L across the group and 39% (n = 7) had lithium level within recommended therapeutic range (0.6-0.8mmol/L).83% (n = 15) of patients met the NICE standards of 3 monthly renal tests, thyroid function test was performed in 89% (n = 16) and at least one serum calcium level was documented in 63% (n = 15). Taking into consideration most recent blood test results, 100% (n = 18) had abnormal renal function, 78% (n = 7) had abnormal thyroid function and 60% (n = 9) had abnormal serum calcium.Half (n = 9) were initiated on lithium by POA service and of these, 56% (n = 5) had documented renal impairment prior to initiation. Of patients on long term lithium therapy at time of referral (n = 9), almost half (n = 4) had a documented history of lithium toxicity.ConclusionThe results of this audit highlight room for improvement in lithium monitoring of older adults attending POA service. Furthermore, all patients prescribed lithium had impaired renal function, half had abnormal calcium and two fifths had abnormal thyroid function. This is an important finding given the associations between those admitted to hospital with COVID-19 and comorbid kidney disease and increased risk of inpatient death.Our findings highlight the need for three monthly renal function monitoring in older adults prescribed lithium given the additive adverse effects of increasing age and lithium on the kidney. Close working with specialised renal services to provide timely advice on renal management for those with renal impairment prescribed lithium is important to minimise adverse patient outcomes.


1992 ◽  
Vol 17 ◽  
pp. 98
Author(s):  
JB Cannata ◽  
MJ Virgós ◽  
MT Allende ◽  
JL Fernández Martín ◽  
C Gómez Alonso ◽  
...  

2021 ◽  
Author(s):  
Mainak Banerjee ◽  
Jan Ahamed ◽  
Subhankar Chowdhury ◽  
Satinath Mukhopadhyay

Abstract OBJECTIVETo analyze the abnormalities in serum parathormone (PTH)-25-hydroxy-vitamin D (25-OHD) axis and calcium phosphate homeostasis in symptomatic PHPT patients having bone disease, nephrolithiasis and impaired renal function (IRF) at diagnosis. METHODSConsecutive adults (>18 years) with diagnosed symptomatic PHPT were enrolled in the retrospective study. Relevant clinical, biochemical and imaging parameters were recorded.RESULTSAdult patients with symptomatic PHPT were identified (N=60, age 45.2±14.4 years, 45 females). Predominant phenotypes were bone disease (osteoporosis and/or clinical fractures, n=42, 70%) and nephrolithiasis (n=24, 40%). Compared to patients with nephrolithiasis only (subgroup C, n=7) and simultaneous bone disease/nephrolithiasis (subgroup D, n=17), patients with isolated bone disease phenotype (subgroup B, n=25) had significantly higher alkaline phosphatase (AlP) and lower 25-OHD levels at presentation. Patient subgroups with nephrolithiasis had higher serum calcium levels and lower effective glomerular filtration rate (eGFR) at presentation. PTH was not significantly different among these subgroups. Patients with IRF (eGFR <60 ml/min per 1.73 m2, n=17) in our cohort had significantly higher serum calcium, phosphate, PTH levels and nephrolithiasis rates. Presence of nephrolithiasis, higher calcium x phosphate product (IRF: 36.2 ± 10.7 versus no IRF: 26.2 ± 5.7 mg2/dl2) and increased PTH levels were independently associated with IRF at diagnosis.CONCLUSIONSWhile PHPT patients with isolated bone disease were found to have lower 25-OHD and higher AlP levels independent of PTH levels; PTH was found to be an independent predictor of impaired renal function at diagnosis.


1964 ◽  
Vol 10 (10) ◽  
pp. 869-890 ◽  
Author(s):  
Alfred Zettner ◽  
David Seligson

Abstract Atomic absorption spectrophotometry (AAS) was applied to the determination of serum calcium. A special diluent was developed to abolish the effect of absorption depressors. This made possible measurement of calcium in directly diluted serum samples without prior removal of any serum constituents. Values obtained by AAS on calcium oxalate precipitates from serum were identical with those found by the direct dilution technique.


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