Biomedical subjects

D R Finco

Publications and source records attributed to D R Finco.

At least 37 records · Page 2Linked to original sources

PubMed1995

Impaired renal autoregulatory ability in dogs with reduced renal mass.

In normal dogs, the renal autoregulatory mechanism limits the effect of changes in renal arterial pressure (RAP) on RBF, renal outer cortical blood flow (OCBF), and GFR by adjusting the vascular tone of the preglomerular arterioles. To determine the extent to which autoregulatory ability was impaired in remnant renal tissue in dogs, the effects of variations in RAP on RBF, OCBF, and GFR were studied after sham-operation (Group 1; N = 5), 3/4 nephrectomy (Group 2; N = 5), or 7/8 nephrectomy (Group 3; N = 5). In Group 1, the RBF, OCBF, and GFR were not significantly affected by variations in RAP between 75 and 125 mm Hg, indicating intact renal autoregulatory ability. In contrast, both groups of partially nephrectomized dogs exhibited a loss of renal autoregulatory ability below 100 mm Hg (P < 0.05). As RAP rose above 100 mm Hg, dogs with 7/8 nephrectomy exhibited a greater increase than control dogs in RBF (0.586 +/- 0.211 versus -0.080 +/- 0.030 percent change in RBF/mm Hg change in RAP; P < 0.05), OCBF (0.408 +/- 0.157 versus -0.059 +/- 0.054 percent change in RBF/mm Hg change in RAP; P < 0.05), and GFR (0.784 +/- 0.230 versus 0.134 +/- 0.049 percent change in RBF/mm Hg change in RAP; P < 0.05). The ability of the renal vasculature to maintain renal function stable above 100 mm Hg was intermediate in Group 2 and not significantly different from corresponding values for Group 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Effects of aging and dietary protein intake on uninephrectomized geriatric dogs.

Thirty-one clinically normal Cocker Spaniels, Miniature Schnauzers, and Doberman Pinschers (28 female, 3 male) 7 to 8 years old were uninephrectomized (month -2) to increase the risk of renal damage associated with reduction of renal mass. Two diets, differing principally in protein concentration, were used to test the hypothesis that high dietary protein intake causes renal damage in aging dogs. For 2 months after uninephrectomy, all dogs were fed diet A (18% protein). After glomerular filtration rate (GFR) was measured (month 0), 16 dogs were assigned to group A and were fed diet A for an additional 48 months. The other 15 dogs were assigned to group B, and were fed diet B (34% protein) for the subsequent 48 months. At 6-month intervals, GFR and urine protein-to-creatinine ratio (UP/C) were determined. At 48 months, terminal studies were done, survivors were euthanatized, and tissues were examined. Of 16 dogs in group A, 10 survived, compared with 13 of 15 in group B. Among survivors, a significant difference in GFR was not found between groups A and B, and decrease in GFR was not evident with time in either group. At 48 months, oral administration of casein caused minor acute effects on GFR and renal plasma flow in dogs of groups A and B. The UP/C values increased significantly (P = 0.001) from baseline values, but the increase was not progressive. The UP/C values were not affected by diet. Some dogs in both groups developed UP/C > 1.0.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1994

Effects of parathyroid hormone depletion in dogs with induced renal failure.

Six parathyroidectomized (PTX) and 6 control dogs had renal mass reduced by 15/16, and were studied for effects of parathyroid hormone depletion on progression of renal failure. All PTX dogs and 4 of 6 control dogs survived until necropsy after 32 weeks. Plasma parathyroid hormone concentration was undetectable in PTX dogs throughout the study, but was greater than normal in control dogs. Serum inorganic phosphate (P) concentration was increased in PTX dogs (6.8 +/- 0.1 mg/dl) and in control dogs (7.5 +/- 0.2), but did not differ significantly (P = 0.254) between groups. Ionized blood calcium values (Ca2+) were significantly (P = 0.014) lower in PTX dogs (1.31 +/- 0.01 mmol/L) than in control dogs (1.36 +/- 0.00 mmol/L), but were more variable in PTX dogs. Values in PTX dogs were not significantly different from those in control dogs for glomerular filtration rate (P = 0.914), plasma creatinine concentration (P = 0.903), and urine protein to creatinine ratio (P = 0.756) determined at intervals during the study. Terminal glucose tolerance and plasma insulin concentrations, P tolerance, and renal P excretion did not differ between groups. Histologic comparison of kidneys removed during reduction of renal mass with kidneys removed at necropsy revealed development of lesions in both groups of dogs, and no protective effect from parathyroidectomy. Mineral analysis of aorta, brain, heart, lungs, and skeletal muscle obtained at necropsy revealed no significant difference between PTX and control groups. Renal cortical calcium concentration was significantly (P < 0.05) greater in kidneys obtained at necropsy then in kidneys obtained during nephrectomy, but PTX did not protect renal cortex from calcium deposition.

Animals↗

PubMed1993

Endogenous creatinine clearance measurement of glomerular filtration rate in dogs.

Renal clearance procedures were performed on adult mixed-breed dogs with a wide range of renal function. Endogenous creatinine clearance was computed after analyzing plasma and urine for creatinine by use of 2 methods, PAP and kinetic Jaffe. For 20-minute clearance procedures, [14C]inulin clearance was measured simultaneously with endogenous creatinine clearance. For 111 twenty-minute clearance procedures performed on 24 dogs, [14C]inulin clearance was highly correlated with creatinine clearance for both methods of creatinine analysis (R2 = 0.979 for [14C]inulin-PAP; R2 = 0.943 for [14C]inulin-Jaffe). The absolute values for PAP and [14C]inulin clearance were nearly the same (PAP-to-[14C]inulin clearance ratio = 1.03 +/- 0.08), but those for Jaffe clearance were substantially less than those for [14C]inulin clearance (Jaffe-to-[14C]inulin clearance ratio = 0.88 +/- 0.10). The Jaffe-to-[14C]inulin clearance ratio was inversely correlated with degree of renal function (R2 = 0.464), whereas the PAP-to-[14C]inulin clearance ratio was not correlated with degree of renal function (R2 = 0.060). Thus, Jaffe-determined creatinine clearance varied, in relation to [14C]inulin clearance, depending on degree of renal function. In 4 clinically normal dogs, 20-minute and 24-hour sample collections analyzed by use of the PAP method gave clearance values significantly greater, for both periods, than did Jaffe analyses. The PAP-determined creatinine clearance values were less than, but not significantly different from 20-minute exogenous creatinine clearance values determined 10 days after 24-hour collections.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Influence of hydration state on renal functions of dogs.

Clinically normal dogs were evaluated in states of dehydration, euhydration, and after fluid administration to determine effects of hydration state on renal clearance values. Endogenous creatinine, exogenous creatinine, and [14C]inulin clearances, were determined to measure glomerular filtration rate (GFR); in some experiments p-aminohippurate clearance was determined to measure renal plasma flow. Dehydration caused significant (P < 0.05) decrease in clearance values, compared with euhydration, and clearance values during euhydration were significantly (P < 0.05) less than values obtained after a single gavage with water (30 ml/kg of body weight). Sustained administration of 3 fluid regimens was evaluated for effects on clearance values (treatment A = 30 ml of lactated Ringer's solution/kg/h; treatment B = 30 ml of water/kg by gavage hourly; treatment C = 10 ml of glucose:lactated Ringer's solution/kg/h). All regimens of fluid therapy caused significant P < 0.05), progressive increases in GFR, but treatment C resulted in the most stable GFR values. Increases in clearance values were associated with positive fluid balance; the rate of fluid administration was greater than the rate of urine formation. Data from 285 GFR determinations on 85 dogs were evaluated retrospectively. For each determination, three 20-minute urine collections were made beginning 40 minutes after 30 ml of water/kg was given by gavage. Values between collections were significantly (P < 0.05) different, but varied by < 3%. Comparison of methods for measurement of GFR indicated that endogenous creatinine clearance and [14C]inulin clearance were highly correlated (R2 = 0.82), but mean clearance values were markedly different (mean +/- SEM, 28.70 +/- 0.01 and 37.07 +/- 1.29 ml/min, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Selective parathyroidectomy of the dog.

Selective parathyroidectomy (PTX) is preferred to thyroparathyroidectomy (TPTX) when specific effects of parathyroid hormone depletion are being studied. However, because of the anatomic proximity of thyroid and parathyroid glands, TPTX often is performed, leaving animals depleted of thyroxine (T4) and calcitonin as well as parathyroid hormone (PTH). In the present study, six normal dogs had parathyroid tissue and about seven-eighths of thyroid tissue removed. This quantity of thyroid tissue was inadequate to maintain normal serum T4 concentrations, despite allowance of 168 days for thyroid recovery. Five of six dogs with reduced renal mass had successful selective PTX and normal serum T4 concentrations at 28 days, when one-half or more of thyroid tissue was spared. We conclude that with attention to the surgical technique, selective PTX can be achieved in a high percentage of dogs and sufficient thyroid tissue spared to maintain euthyroidism.

Animals↗

PubMed1992

Effects of dietary phosphorus and protein in dogs with chronic renal failure.

Four diets were formulated to contain: 16% protein and 0.4% phosphorus--diet 1; 16% protein and 1.4% phosphorus--diet 2; 32% protein and 0.4% phosphorus--diet 3; and 32% protein and 1.4% phosphorus--diet 4. Forty-eight dogs were fed diet 1 for 3 months after surgical reduction of renal mass, then were allotted to 4 groups of 12 dogs each, with equal mean values for glomerular filtration rate (GFR). Dog of groups 1-4 were fed diets 1-4, respectively, for 24 months. Data collected from the dogs during and at termination of the study were analyzed statistically for effects of dietary protein, phosphorus (P), time, and interactions between these factors. During the 24 months of study, 24 dogs developed uremia and were euthanatized for necropsy. Necropsy also was performed on the remaining 24 dogs after they were euthanatized at the end of the study. Dog survival was significantly enhanced by 0.4% P diets (vs 1.4% P diets), but survival was not significantly influenced by amount of dietary protein. The 0.4% P diets (vs 1.4% P diets) significantly increased the period that GFR remained stable before it decreased, but dietary protein did not have significant effect. Significant blood biochemical changes attributed to P, protein, and time were identified during the study. Terminally, plasma parathyroid hormone concentration was significantly increased from prediet values in all groups of dogs. Urine protein excretion was not significantly affected by dietary amount of either protein or P, when measured by either timed urine collection or urine protein-to-creatinine ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Effects of phosphorus/calcium-restricted and phosphorus/calcium-replete 32% protein diets in dogs with chronic renal failure.

Twenty-four dogs with induced, severe chronic renal failure were allotted to 2 groups of 12 each. Group-A dogs were fed a 0.4% phosphorus (P)/0.6% calcium, 32% protein diet, and group-B dogs were fed a 1.4% P/1.9% calcium, 32% protein diet. Dogs were studied over 24 months to determine clinical status, survival, blood biochemical alterations, glomerular filtration rate (GFR), urinary excretion of P and protein, renal morphologic changes, and renal tissue concentrations of calcium, P, and magnesium. Group-A dogs developed statistically significant differences from group-B dogs in several blood biochemical values (PCV and total solids, calcium, P, potassium, sodium, chloride, total CO2 (TCO2), anion gap, and parathyroid hormone concentrations) and in urinary P excretion. Mean (+/- SEM) GFR values in group-A and group-B dogs were nearly identical when diets were initiated (group A = 0.73 +/- 0.05 ml/min/kg of body weight; group B = 0.72 +/- 0.08 ml/min/kg), but significantly (P = 0.0346) lower GFR developed in group-B than in group-A dogs over time. At 24 months, GFR in survivors was 0.83 +/- 0.08 and 0.63 +/- 0.15 ml/min/kg for dogs of groups A and B, respectively. Other measurements favored the hypothesis that P/calcium restriction was beneficial, but values failed to reach statistical significance. Survival was greater at 24 months in group-A than in group-B (7 vs 5) dogs, and renal tissue concentrations of calcium and P were higher in group-B than in group-A dogs. Differences were not detected between groups in urinary excretion of protein and in the type or severity of renal lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗

PubMed1992

Characterization of the renal response to protein ingestion in dogs with experimentally induced renal failure.

Effects of a protein meal (2.7 g of casein/kg of body weight) on glomerular filtration rate (GFR) and renal plasma flow (RPF) were assessed in dogs after 15/16 nephrectomy (n = 10), and were compared with observations in dogs with intact kidneys (n = 5). Increase in GFR and RPF was observed in both groups of dogs between 1.5 and 8 hours after protein ingestion. A maximal value for GFR was observed between 4 and 5 hours after protein ingestion in dogs of both groups. Enhancement of urinary protein excretion was evident in partially nephrectomized dogs after protein ingestion (P less than 0.05), a result that was confirmed by 24-hour total urine collection from partially nephrectomized dogs fed a balanced ration. A qualitatively similar vasodilatory response was observed in partially nephrectomized dogs and in dogs with intact kidneys, and the mean maximal increase of GFR and RPF expressed as a percentage of baseline values in the latter dogs (47.0 +/- 8.1 and 43.6 +/- 10.3%, respectively) exceeded that observed in partially nephrectomized dogs (20.8 +/- 2.2 and 22.7 +/- 6.3%, respectively; P less than 0.01). The incremental response of the kidneys to protein ingestion was directly related to the degree of renal function, as reflected in the linear regression relationship between the incremental increase in GFR and the baseline value for GFR (P less than 0.01, R2 = 0.721).

Animals↗

PubMed1991

Dietary protein intake and the glomerular adaptations to partial nephrectomy in dogs.

After partial nephrectomy (Nx) in rats, a temporal pattern of progressively declining renal function often develops. This pattern has been attributed to the development of glomerular hyperfiltration, hypertension and hypertrophy in remnant nephrons. In rats, dietary protein restriction prevents these adaptive changes in remnant nephrons, thereby preserving renal structure and function. However, long-term studies of the temporal pattern of renal function have failed to identify a consistently progressive deterioration of renal function in partially Nx dogs, and a protective effect of protein restriction has not been apparent in this species. To address these issues in dogs, we evaluated the single nephron adaptations to partial Nx in dogs and the effect of dietary protein restriction on these adaptations. Results of our micropuncture studies in partially Nx dogs indicate that remnant nephrons of dogs exhibit glomerular hyperfiltration (single nephron glomerular filtration rate of 144 +/- 8 vs. 71 +/- 4 nL/min in controls, P less than 0.05), hypertension (glomerular capillary pressure of 75.1 +/- 1.6 vs. 63.2 +/- 1.9 mmHg in controls) and hypertrophy (glomerular volume of 3.54 +/- 0.24 x 10(6) vs. 2.04 +/- 0.05 x 10(6) microns3 in controls, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Beneficial effects of dietary mineral restriction in dogs with marked reduction of functional renal mass.

Although studies in partially nephrectomized rats have identified a progressive nephropathy that is altered by dietary restriction of phosphorus intake, the response of dogs to similar perturbations has not been established. Functional renal mass was reduced by 15/16 in dogs to determine its long-term effects on renal function and to evaluate the effects of two levels of dietary mineral (calcium and phosphorus) intake (0.44% phosphorus/0.57% calcium versus 1.50% phosphorus/1.91% calcium). Following a 3-month stabilization period, dogs were fed either the lower mineral diet (group 1, N = 12) or the higher mineral diet (group 2, N = 12) for 24 months. Loss of renal function with the passage of time was observed in 10 of 12 dogs maintained on the higher mineral diet, with an average decrease in exogenous creatinine clearance of 11.1 +/- 6.3%/month, leading to a survival rate of 33% in this group. Restriction of dietary mineral intake slowed (P less than 0.05) the rate of decline of exogenous creatinine clearance in group 1 to 2.6 +/- 1.1%/month and improved 24-month survival to 75% (P less than 0.01). Deterioration of renal function was associated with renal calcium accumulation and histologic evidence of nephrocalcinosis, tubular atrophy and dilatation, and interstitial fibrosis. These events were more readily apparent in female than in male dogs. A role for glomerulosclerosis was not apparent, and neither glomerular pathology nor glomerular volume was related to the observed decrements in renal function.

Animals↗

PubMed1991

Exogenous creatinine clearance as a measure of glomerular filtration rate in dogs with reduced renal mass.

Renal mass was surgically reduced in 78 dogs by uninephrectomy or by combined renal infarction and uninephrectomy. Renal clearance of inulin and renal clearance of exogenous creatinine were determined simultaneously, and the creatinine to inulin clearance (C/I) ratio was calculated. Clearance procedures were performed 2 to 3 months after reduction of renal mass, and were repeated at intervals thereafter. Overall, the C/I ratio was 1.008 +/- 0.007 for 192 determinations, with a highly significant correlation (R2 = 0.994, P less than 0.0001) between creatinine clearance and inulin clearance. There was no significant effect of gender of dogs, time after partial renal ablation, or dietary protein intake on C/I ratios. Degree of renal ablation did not affect C/I ratios. The results indicated that exogenous creatinine clearance is a valid measure of glomerular filtration rate in both male and female dogs with reduced renal mass.

Animals↗

PubMed1991

Effect of dietary protein on functional, morphologic, and histologic changes of the kidney during compensatory renal growth in dogs.

Two diets similar in caloric density and mineral content, but markedly different in protein content, were used to study the effects of dietary protein on renal function and morphologic and histopathologic changes in dogs that had functional renal tissue reduced by seven-eights nephrectomy. The effects of moderate protein intake (MPrI = 15% protein; dry-matter basis) and high-protein intake (HPrI = 31% protein; dry-matter basis) were studied for the initial 7 months (period 1 [P1]) after renal mass reduction. Diets were then switched between groups during the following 7 months (period 2 [P2]) to evaluate the effects of increased or decreased protein intake. The HPrI caused significantly (P less than 0.05) greater glomerular filtration rate (GFR) and renal growth than did MPrI during P1. Dogs that maintained HPrI during P1 and MPrI during P2 (group 1) had significant (P less than 0.05) reduction in GFR during P2. Dogs that maintained MPrI during P1 and HPrI during P2 (group 2) had significant (P less than 0.05) improvement in GFR and renal growth during P2. At the end of the study, renal reserve was evaluated in both groups of dogs before and after group 1 was returned to HPrI for 2 weeks. During this 2-week feeding trial, group-1 dogs had marked improvement in renal reserve, relative to group 2, and GFR increased to the terminal P1 values. Results indicate a possible residual benefit from HPrI during the early phase of compensatory renal growth in the form of functional compensatory memory to HPrI. The severity of renal lesions was indistinguishable between dogs of dietary groups during both study phases.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

PubMed1990

Suspected familial renal disease in chow chows.

Renal disease was diagnosed in 6 young Chow Chows. Clinical abnormalities included vomiting, polyuria, polydipsia, and weight loss. Common abnormal laboratory findings were azotemia, hyperphosphatemia, hypocalcemia, nonregenerative anemia, and low urine specific gravity. All 6 dogs had similar microscopic renal lesions. characterized by interstitial fibrosis, a population of small glomeruli, and lack of inflammatory cells. A familial basis for the renal disease is suggested because of its development in 4 closely related dogs.

Animals↗

PubMed1990

Single-nephron adaptations to partial renal ablation in the dog.

Micropuncture and histological studies were performed in dogs to characterize single-nephron adaptations to partial renal ablation. Dogs underwent sham surgery (group 1, n = 6), three-fourths nephrectomy (group 2, n = 10), or seven-eighths nephrectomy (group 3, n = 6). Single-nephron glomerular filtration rate (SNGFR) was 71.0 +/- 4.2 nl/min in group 1, 132.5 +/- 9.6 nl/min in group 2, and 161.8 +/- 12.4 nl/min in group 3 (P less than 0.05). There were parallel increases in single-nephron glomerular plasma flow rate (GPF), with a mean value of 235.3 +/- 20.1 nl/min in group 1, 442.4 +/- 34.4 nl/min in group 2, and 569.6 +/- 73.7 nl/min in group 3 (P less than 0.05, group 1 vs. groups 2 and 3). Glomerular capillary pressure, estimated from the sum of proximal tubule stop-flow pressure and arterial oncotic pressure, was 63.2 +/- 1.9 mmHg in group 1, 73.5 +/- 2.0 mmHg in group 2, and 77.9 +/- 2.2 mmHg in group 3 (P less than 0.05, group 1 vs. groups 2 and 3). The mean glomerular transcapillary hydraulic pressure gradient (delta P) in group 2 was not different from group 1 (46.8 +/- 1.3 vs. 43.9 +/- 1.8 mmHg, NS); however, it was significantly increased in group 3 (50.0 +/- 1.4 mmHg; P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗

PubMed1990

Determination of excretion of inulin, creatinine, sodium sulfanilate, and phenolsulfonphthalein to assess renal function in goats.

Excretion of creatinine, sodium sulfanilate (SS), and phenolsulfonphthalein (PSP) was studied in healthy goats. In conscious goats, mean (+/- SEM) inulin clearance was 2.26 +/- 0.08 ml/min/kg of body weight. Endogenous creatinine clearance, 1.97 +/- 0.09 ml/min/kg, underestimated inulin clearance (P less than 0.01), probably because of the presence of noncreatinine chromogens in caprine plasma. The estimated renal clearance of PSP was 6.88 +/- 0.39 ml/min/kg, whereas the estimated renal clearance of SS was 3.71 +/- 0.39 ml/min/kg. Both exceeded inulin clearance (P less than 0.01), confirming renal tubular secretion of both compounds. In 6 anesthetized goats, exogenous creatinine clearance and SS clearance exceeded inulin clearance (P less than 0.05). Results of stop-flow experiments documented secretion of creatinine and SS by the proximal portion of the caprine nephron. Plasma half-life of PSP in uninephrectomized goats exceeded that in intact goats (20.2 +/- 1.5 min vs 11.9 +/- 0.7 min; P less than 0.01). Similarly, plasma half-life of SS was greater in goats after uninephrectomy (58.2 +/- 6.2 min vs 30.4 +/- 1.2 min; P less than 0.01).

Animals↗

PubMed1990

Glucose conservation by the kidney and effect of systemic glucose infusion on inulin clearance in female goats.

In 6 female goats, the mean threshold for glucosuria was 159.5 +/- 4.3 mg/dl. During increasing filtered loads of glucose, renal reabsorption of glucose reached maximal capacity, which was not exceeded when plasma glucose concentration was increased further. Measured in 10 female goats, the transport maximum for glucose was 119.1 +/- 9.1 mg of glucose reabsorbed/min. During infusion of glucose, there was a significant (P less than 0.05) time-dependent reduction in inulin clearance indicating that IV glucose administration may be inappropriate in goats with compromised renal function.

Animals↗

PubMed1989

Influence of dietary source of phosphorus on fecal and urinary excretion of phosphorus and other minerals by male cats.

Twelve male cats were fed 2 diets that differed in the source of P. In diet 1 (1.4% P), 62.7% of P originated from poultry, meat, and fish meal, and the remainder from other organic ingredients of food. In diet 2 (1.6% P), 63.5% of P was derived from neutral monobasic/dibasic salts, and the remainder from other organic ingredients of the food. The P intake was nearly the same with both diets, but there was a significant (P less than 0.05) difference between diets in the percentage of ingested P that was excreted in the urine (14.7 +/- 5.3% for diet 1; 34.9 +/- 8.4% for diet 2), and in 6-day urinary P excretion (774 +/- 290 mg for diet 1; 2,004 +/- 556 mg for diet 2). The P concentrations in urine samples obtained by cystocentesis after cats ate were significantly (P less than 0.05) higher when cats were fed diet 2 than when those same cats were fed diet 1. Plasma P concentrations increased after ingestion of diet 2, but were unchanged after ingestion of diet 1. Seemingly, urinary excretion of P was markedly influenced by dietary composition. Diets with the same P content have potential for different biologic effects because of differences in availability of P.

Animals↗