Neonatal Proteinuria in Calves-A Quantitative Approach.

Urine testing is a convenient, non-invasive method of obtaining information about body functions. Depending on the intended purpose, urine testing may be qualitative and/or quantitative. Urine analysis can also include proteins. There are no data in the literature on the occurrence of proteinuria in healthy neonatal calves. The present study was the first that aimed to quantify the hypothesis of proteinuria occurrence in these animals in the first week of life, to assess its intensity and dynamics and to understand the underlying causes of proteinuria in healthy calves. The research was carried out on 15 healthy calves in the first seven days of life. Calves were catheterized to determine minute diuresis. Total protein concentration was determined in blood plasma and urine. Urine proteins were separated by electrophoresis (SDSPAGE) and their concentration and percentage were determined by densitometry using an image archiving and analysis software. The separated proteins were divided into three groups according to molecular weight for albumin, LMW and HMW proteins. The results were standardized per 1 m2 of body surface area and statistically analyzed. Neonatal proteinuria was demonstrated in healthy calves, mainly resulting from the high concentration of LMW proteins in the urine. Their percentages decreased significantly from 84.46% on the first day of calves' life to 64.02% on day 7. At the same time, a statistically significant increase was observed in the proportion of albumin and high molecular weight proteins in urine total protein. Albumin percentage increased from 9.54% (on day 1) to almost 20% (on day 7), while the proportion of HMW proteins increased from 6.68% to 18.13%, respectively. The concentration of total protein in the urine of newborn calves amounted to 14.64 g/L and decreased statistically significantly during the first 72 h of postnatal life, stabilizing at the level of 3-4 g/L. The mean value of total protein excretion in the first week of life was 4.81 mg/min/m2 (i.e., 6.93 g/24 h/m2). The analysis of protein concentration in the urine and its excretion, as well as changes in urinary excretion of the tested protein fractions, indicated that neonatal proteinuria in healthy neonatal calves was tubular (i.e., main reason is the reduced absorption of proteins in nephrons). In addition, research showed that there was a rapid improvement in resorptive mechanisms in tubular cells. It should be assumed that the filtration barrier in the kidneys of these animals after birth is morphologically prepared to retain high molecular weight proteins. It seems that the increased permeability of the filtration barrier in the glomeruli does not necessarily indicate the immaturity of the kidneys, but may indicate the kidneys' adaptation to excess protein removal from the body during feeding with high-protein food (colostrum), with an open intestinal barrier enabling protein absorption from the gastrointestinal tract to the blood.

Human sperm proteins identified by 2-dimensional electrophoresis and mass spectrometry and their relevance to a transcriptomic analysis.

The aim of this study was to identify and analyse human sperm proteins from normozoospermic men using 2-dimensional electrophoresis (2-DE) and mass spectrometry (MS). We identified 73 different sperm proteins, including two less characterized human sperm proteins, Annexin A7 (ANXA7) and c14orf105. Bioinformatic analysis of detected sperm proteins revealed new carbohydrate and lipid metabolic pathways, which supply energy to motile sperm. A comparison of our data with available mRNA microarray data from the human testis allows for validation of identified sperm proteins and aids in the recognition of their physiological pathways.

Effects of immunosuppressive treatment on protein expression in rat kidney.

The structural proteins of renal tubular epithelial cells may become a target for the toxic metabolites of immunosuppressants. These metabolites can modify the properties of the proteins, thereby affecting cell function, which is a possible explanation for the mechanism of immunosuppressive agents' toxicity. In our study, we evaluated the effect of two immunosuppressive strategies on protein expression in the kidneys of Wistar rats. Fragments of the rat kidneys were homogenized after cooling in liquid nitrogen and then dissolved in lysis buffer. The protein concentration in the samples was determined using a protein assay kit, and the proteins were separated by two-dimensional electrophoresis. The obtained gels were then stained with Coomassie Brilliant Blue, and their images were analyzed to evaluate differences in protein expression. Identification of selected proteins was then performed using mass spectrometry. We found that the immunosuppressive drugs used in popular regimens induce a series of changes in protein expression in target organs. The expression of proteins involved in drug, glucose, amino acid, and lipid metabolism was pronounced. However, to a lesser extent, we also observed changes in nuclear, structural, and transport proteins' synthesis. Very slight differences were observed between the group receiving cyclosporine, mycophenolate mofetil, and glucocorticoids (CMG) and the control group. In contrast, compared to the control group, animals receiving tacrolimus, mycophenolate mofetil, and glucocorticoids (TMG) exhibited higher expression of proteins responsible for renal drug metabolism and lower expression levels of cytoplasmic actin and the major urinary protein. In the TMG group, we observed higher expression of proteins responsible for drug metabolism and a decrease in the expression of respiratory chain enzymes (thioredoxin-2) and markers of distal renal tubular damage (heart fatty acid-binding protein) compared to expression in the CMG group. The consequences of the reported changes in protein expression require further study.

Morphological, histochemical and immunohistochemical studies of polar fox kidney.

The aim of the present study was to evaluate the morphology and intermediate filaments cytokeratin, desmin and vimentin expression in the kidneys of the polar fox (Alopex lagopus). Routine morphological, histochemical and immunohistochemical techniques of examinations of the kidneys of adult male and female polar foxes were used. We found different localizations and different levels of immunoexpression of cytokeratin in epithelia of calyxes, distal tubules and Henle's loops, and also in endothelial cells. We also noted immunolocalization and immunoexpression of vimentin in mesangial cells, interstitial tissue and distal tubules. Desmin reactivity was revealed for muscle cells of arteries and mesangial cells. Our study is the first attempt to localize cytoskeletal intermediate filaments performed on polar fox kidneys. It is worth noting that our observations concerning the distribution of vimentin in the polar fox kidney may suggest that protein as being useful as a marker of distal tubules in the polar fox kidney.

Renal regulation of potassium homeostasis in calves in the first week of life including the role of atrial natriuretic peptide.

The experiment was carried out on 10 clinically healthy Polish-Friesian var. Black-and-White cow calves, during the first seven days of postnatal life. The results indicate that renal removal of potassium depends primarily on the quantity reabsorbed in the tubules, whereas clearance of the electrolyte, due to stable levels in the blood plasma, depends on the amount excreted in the urine. With stable tubular reabsorption of potassium, a relatively unchanging amount of excreted potassium was observed in the urine. However, reduced tubular reabsorption caused a significant increase in excretion and clearance of the electrolyte. Changes in the amount of filtered potassium play a minor role in the regulation of excretion. Small changes in the blood plasma potassium concentration observed primarily resulted from changes in glomerular filtration rate and tubular reabsorption, since the concentration of electrolyte in the blood after birth remained within the physiological range. The results ofthis study suggest that neonate calf kidneys are sufficiently prepared to regulate kalemia. Atrial natriuretic peptide is not directly involved in the regulation of tubular reabsorption of potassium in calves in the first week of life, although it is highly likely that the peptide is involved in the excretion of potassium in the urine in calves during the first seven days of life.

Comparative study of selected blood biochemical components in milk or milk-replacer fed calves during the second week of life.

The experiment was carried out on 13 male Polish Black and White dairy calves of 75% share of the Holstein-Friesian (HF) breed during the second week of life. The animals were divided into two groups. One group (n=7) was fed mother's milk and the second (n=6) milk replacer. The dynamics of changes in concentration of selected blood biochemical components connected with nitrogen metabolism (plasma total protein, albumin, urea, endogenous creatinine) and with mineral metabolism (sodium, chloride, calcium, magnesium, zinc, copper and plasma osmotic pressure) were analyzed in both groups. The results show that the type of ingested food influences the concentration of indicators reflecting nitrogen metabolism. Changes of these parameters in calves fed milk replacer are possibly connected with advantageous catabolic changes. Stable concentrations of main extracellular fluid electrolytes and blood plasma osmotic pressure were found in both groups of calves. Constant blood plasma calcium, magnesium, zinc and copper concentrations observed during this study might also indicate the relative maturity of mechanisms maintaining water and electrolyte balance. Nevertheless, it seemsjustifiable to monitor the copper concentrations in plasma of young calves.

Age-related changes of selected blood biochemical indicators in dairy calves during their first week of life.

The aim of this study was to determine the influence of age and ingested food (colostrum and mature milk) on the concentrations of selected blood biochemical components connected with nitrogen and mineral metabolism in dairy calves during their first week of life. The experiment was carried out on 13 Polish Black and White breed dairy calves. The animals were fed colostrum within the first 3 days of postnatal life and thereafter the mature milk of their dams until the end ofthe experiment (7 days). The obtained results showed that intensive catabolic and anabolic changes in nitrogen occur in the first week of life. These changes were particularly intense during the first 24-48 hours of life and may reflect dynamic tissue remodelling. The results of this experiment also show that healthy calves efficiently regulate water and electrolyte homeostasis.

Renal regulation of sodium, potassium and chloride balance in single- and twin-pregnant goats.

The aim of these studies was to analyse and compare changes in selected parameters of renal function in terms of water-electrolyte balance regulation in single- and twin-pregnant goats. Clearance analyses were carried out on 16 pregnant White Improved goats (8 in single and 8 in twin gestation). Blood plasma and urine samples were analysed for the concentration of inulin, endogenous creatinine, sodium, potassium, and chlorides. It has been demonstrated that glomerular filtration rate (GFR) in the goat kidney does not change significantly during gestation. GFR recorded from the 1st week until the 20th week of gestation in twin-pregnant goats was only slightly higher compared to those observed in single-pregnant does. Blood plasma concentrations of major electrolytes, i.e. sodium, potassium and chloride ions, did not differ significantly in pregnant and non-pregnant goats, and remained within the reference values. From the very beginning of gestation, the single-pregnant goats showed increased renal potassium clearance; however, the level of sodium clearance remained stable. On the other hand, sodium clearance increased from the 2nd month of gestation in the twin-pregnant goats, while the load of excreted potassium did not change. These changes had probably resulted from varied levels of aldosterone and progesterone and their mutual proportions differing between the groups.

Effect of converting enzyme inhibitor on copper and iron concentrations of blood plasma in calves during the neonatal period.

The converting enzyme catalyzes the conversion of angiotensin I to angiotensin II. Ang II is the key component of the renin-angiotensin-aldosterone (RAA) system, regulating water-electrolyte balance in newborn calves. Captopril is an inhibitor of the angiotensin-converting enzyme. The aim of this study was to examine the effect of captopril-induced reduction of convertase activity on copper and iron concentrations of blood plasma in calves. The experiment was carried out on 10 Holstein-Friesian female calves, during the first week of life. Copper and iron concentrations in blood plasma were examined before and after captopril administration (0.5, 1, 2, 4, and 6 hours after giving the inhibitor) on subsequent days of the experimental period. The results demonstrated that the copper concentration of blood plasma increased with age. On the seventh day, the copper concentration stabilised at the level observed in adult cattle. Measured before captopril administration, the iron concentration in blood plasma changed: the highest iron concentration was observed on the first day of life, which was followed by a decrease on the third day, and thereafter an increase on the seventh day. These changes may significantly influence the neonatal adaptation of newborn calves, particularly hemopoiesis efficiency. Captopril did not cause statistically significant changes in plasma copper concentration in calves. However, the reduction of angiotensin convertase activity induced by captopril administration resulted in a drop of plasma iron concentration, observed already within 1-2 hours after administration of the inhibitor, and especially within two days post partum. The results indicate that an efficient mechanism maintaining a constant concentration of selected minerals may involve changes in the reabsorption of these minerals from the system fluids to tissues.

Renal regulation of calcium-phosphate metabolism in single- and twin pregnant goats.

The aim of this study was the clearance assessment of renal function in single- and twin-pregnant goats and a comparison of selected parameters associated with calcium-phosphate management in terms of litter size. Clearance studies were carried out on 16 pregnant Polish White Improved goats (8 single pregnancies and 8 twin pregnancies). It was demonstrated that the kidneys of pregnant goats regulate the calcium-phosphate balance to a great extent. In spite of observed differences in parameters of renal functions, plasma calcium and inorganic phosphorus concentrations were comparable with normal reference values in further weeks of pregnancy. Significant differences in renal function between single and twin pregnancies were not observed. Gut absorption and/or bone tissue metabolism seem important for the maintenance of appropriate calcium-phosphate status.