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Biomedical subjects

C Kleinknecht

Publications and source records attributed to C Kleinknecht.

At least 55 records · Page 3Linked to original sources
PubMed1987

Ocular changes in some progressive hereditary nephropathies.

Ocular involvement is a common feature of three hereditary nephropathies: cystinosis, nephronophthisis and Alport's syndrome. The follow-up of 25 cases of infantile cystinosis over a period of 26 years demonstrated that the corneal and retinal epithelium were affected in the same way as the kidney epithelium. Corneal involvement induced photophobia and discomfort, but actual blindness was mainly due to retinal involvement, and therefore no corneal graft was performed. The use of topical cysteamine appears to be promising, but its production raises many questions so no definitive conclusions may be made. Since 1965, 51 patients with nephronophthisis have had ocular examinations; all patients had characteristic clinical symptoms and histological findings. The first group, which consisted of 18 children, all under 10 years of age, was found to have obvious chorioretinal degeneration. The second group, which consisted of 11 children, had a normal ocular examination and normal electroretinogram (ERG). The third group, consisting of 22 children, had a normal clinical examination but ERG tracings with variable alterations. In 28 instances of Alport's syndrome, two types of ocular abnormalities have been observed. In six cases, an anterior lenticonus was noted, which caused a major decline in visual acuity. Retinopathy, which did not affect vision, was observed in 13 cases.

Adolescent↗
PubMed1986

Role of amount and nature of carbohydrates in the course of experimental renal failure.

The renal effects of carbohydrates (CHO) were studied in two experiments. 1) The effects of CHO-energy restriction was evaluated by comparing uremic growing rats (initial weight: 80 g) fed "ad lib" (L rats) or CHO-restricted (starch and glucose) but receiving identical amounts of all other nutrients (R rats). R rats showed reduced growth, slower increase in plasma creatinine, lower mortality rate, and less histological renal damage than L rats. 2) Two types of CHO restriction, low glucose (R1 rats) or low starch (R2 rats) were compared to "ad lib" feeding (L1 rats) in adult rats (initial weight: 130 g). Growth was identically reduced in R1 and R2 rats. Mean plasma creatinine levels at week four was lower in R1 than in L1 rats. The overall rate mortality was higher for L1 and R2 than in R1 rats (79%, 81%, 53%) but included deaths from other causes than renal failure. Actuarial survival excluding these deaths was 27%, 83% and 10% in L1, R1 and R2 rats, respectively. Diffuse renal lesions were found in 25 of 30 L1, 5 of 15 R1, and 12 of 15 R2 rats (R1 vs. R1 and R2, P less than 0.01). The results show that CHO restriction may preserve the renal parenchyma, and suggest that restriction of "simple" rather than "complex" CHO restriction may be beneficial, a finding which could be of clinical importance if confirmed by further investigations.

Animals↗
PubMed1986

Efficiency of substitution of 2-ketoisocaproic acid and 2-ketoisovaleric acid in the diet of normal and uremic growing rats.

Effects of various intakes of the ketoanalogues of leucine (KICA) and valine (KIVA) on growth, nitrogen, and urea excretion were examined and compared to those of an optimal intake (A) of the corresponding amino acids. Diet KICA and KIVA contents varied from 1 to 4 times A. In controls, growth was significantly reduced with equimolar substitution, corrected with twice A, and unchanged at higher levels. Doubling KICA corrected growth except with substantial anorexia. In uremic rats fed KIVA, growth was corrected at twice A. Low-KICA diets reduced plasma-leucine level; higher KICA diets normalized plasma leucine and revealed branched-chain amino acid (BCAA) antagonism. Changes in 2-ketoacids were unrelated to those of BCAA. In uremia, KICA decreased plasma and urinary urea without changing nitrogen retention. Ketoacid substitution for amino acids was 50% efficient in normal rats and not altered by uremia. BCKAs, specifically KICA, could modify urea metabolism.

Animals↗
PubMed1983

[Nutritional factors in the development of experimental renal failure].

Several experimental studies have shown that the development of glomerular sclerosis during aging in rats is related to nutritional factors: it is impeded by overall food restriction, as well as by reduction of the protein, carbohydrate or sodium intake. It is enhanced by high protein or high sodium diets. In remnant kidneys, lesions develop that are similar to those in aging kidneys and that seem to be influenced by the same factors. Through several experiments, we have shown that the rapidity of the deterioration of renal function after subtotal nephrectomy is closely related to the protein intake and that the length of survival can be reduced by a high protein diet or increased by a low protein diet. The influence of protein intake remains clearly apparent when the intake of all other nutrients, particularly minerals, and of calories is strictly controlled. Low protein diets supplemented with essential amino acids resulting in increased appetite are of little benefit for survival, suggesting that the calorie intake or growth-related factors may be of significance. Prolonged survival observed with phosphorus (P) deficient diets compared to low or normal P diets is mainly due to decreased appetite. The optimal supply of protein, energy, sodium and other nutrients should be determined according, not only to nutritional status, but also to effects on the renal parenchyma.

Aging↗
PubMed1983

Growth and development of nondialyzed children with chronic renal failure.

Thirty-four children with severe kidney disease, either congenital (32 cases) or developing at birth, were followed until age 5 to 19 years. Overall growth retardation corresponded to -2.5 SD below the mean normal values. The retardation occurred almost exclusively before therapy for it was started. Fifteen children were first treated during infancy. In all of them except one, growth was dramatically improved following the first visit to our center, growth changing from slowed to normal rate, although catch-up growth was rare: the average change from normal mean height was -1.68 SD (or -5 SD per year) calculated for the infantile period up to the first visit to our clinic, followed by a change of +0.18 SD per year between first presentation and age 12 months, and +0.01 SD per year between first presentation and last observation at a mean age of 8.3 years. In the 19 patients who were treated after the first year of life, the mean change of height from birth to first presentation was -0.33 SD per year followed by a mean change of -0.04 SD per year up to the last observation (mean period, 7.3 years). Catch-up growth was exceptional. Five children entered puberty with a normal growth spurt. When GFR deteriorated, growth velocity was unchanged. Height calculated for corresponding bone maturity was reduced in half of the patients when first seen, but progressed to the same degree as height during follow-up, except in one patient. Mental development was normal in 31 of 34 patients. Conclusion. Normal growth rate and normal development is possible in children and even in infants with CRF chronic renal failure. The importance of instituting early conservative treatment to prevent height loss must be emphasized.

Body Height↗
PubMed1983

Adverse effect of proteins on remnant kidney: dissociation from that of other nutrients.

Several experiments have shown that deterioration of renal parenchyma after reduction of functional mass is affected by the protein content of the diet. The respective role of proteins and that of other nutrients that vary with proteins were never clearly separated. Three groups of 9 uremic rats received diets differing exclusively in protein (casein) content, which was 8% (group 1), 16% (group 2), and 32% (group 3). Energy and minerals were maintained identical. Food intake was similar in groups 1 and 2 and was lower in group 3. Mortality rate remained closely related to protein intake. Of group 3 rats, 78% died within 10 weeks and 100% within 15 weeks. Of group 2 rats, 56% were dead at week 15, and 100% at week 30. Mortality occurred significantly later in group-1 rats fed the lowest protein diet. Histology of remnant kidneys showed severe glomerular and tubular damage, with no or little calcium deposits despite normal phosphorus diet and frequent hyperphosphatemia. These data suggest that protein intake, independent of any other nutrient, influences survival by accelerating the renal damage in rats with reduced kidney mass.

Acute Kidney Injury↗
PubMed1983

Comparison of three low-nitrogen diets containing essential amino acids and their alpha analogues for severely uremic children.

Six infants, 4.5 to 19 months old, whose creatinine clearance was less than 6 ml/min/1.73 m2 received, successively, three low-nitrogen diets. Diet A contained 9.3 g of human milk protein; and diet B, 4.2 g of human milk protein plus synthetic essential amino acids. Diet C was the same as B except that five essential amino acids were replaced by alpha-keto and hydroxy analogs. Serum urea decreased as the infants were transferred from diet A to diets B and C, and the serum urea/creatinine ratio decreased from diet A to diet B and from diet B to diet C. Urea appearance was 14.8 +/- 4.5, 9.1 +/- 4.3, and 6.9 +/- 1.7 mmoles/day, with diets A, B, and C, respectively. Weight gain was also lowest with diet C, as was the difference between nitrogen intake and urea nitrogen appearance, an indicator of nitrogen balance. Plasma free amino acids were not modified by diets A and B, but valine, leucine, and the plasma free essential amino acid pool decreased significantly with diet C.

Amino Acids, Essential↗
PubMed1983

Adverse effect of indomethacin in experimental chronic nephrosis.

The effects of long-term indomethacin therapy were studied in rats with chronic nephrosis induced by puromycin of aminonucleoside (PAN). Fifteen PAN rats received indomethacin (2 mg/kg/d) administered by daily gavages, and fifteen received glucose. A control group received indomethacin but no PAN. Three to five animals per group were sacrificed monthly. Proteinuria was similar in both PAN rat groups. Renal function and histology were normal in the control rats. In the PAN animals, renal failure developed earlier in the treated rats than in the others. Histological examination revealed in all PAN rats early tubulo-interstitial lesions and progressive glomerular damage. The pattern of the lesions was identical in both PAN rats, but the glomerular changes developed earlier, were more diffuse and more severe in the indomethacin treated rats. Thus, indomethacin resulted in an accelerated destruction of the glomeruli in experimental nephrosis. Such a deleterious effect remains unexplained, and its relevance to human disease is not demonstrated.

Animals↗