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Biomedical subjects

L Portmann

Publications and source records attributed to L Portmann.

At least 37 records · Page 2Linked to original sources
PubMed1990

Does medullary sponge kidney cause nephrolithiasis?

The prevalence of medullary sponge kidney in patients with nephrolithiasis and the issue of whether or not medullary sponge kidney has a role in the pathogenesis of renal stones are controversial. We studied the excretory urograms of 280 patients with nephrolithiasis and 280 patients without either nephrolithiasis or a history of renal stones to determine the frequencies of medullary sponge kidney in the two groups. The criterion for the diagnosis of medullary sponge kidney was the presence of a minimum of three linear or round collections of contrast material within one renal papilla. In the patients with nephrolithiasis, we also looked for biochemical evidence of metabolic causes of renal stones. The frequency of medullary sponge kidney was 12% in patients with nephrolithiasis compared with 1% in patients without nephrolithiasis. The statistical difference was highly significant (chi square = 27.1; p less than .001). Metabolic disorders accounting for the lithiasis were detected in 93% of the patients with stones without medullary sponge kidney. Such evidence was present in 60% of patients with stones and medullary sponge kidney. The statistical difference was significant (chi square = 25.8; p less than .001). Our results suggest that medullary sponge kidney is a cause of nephrolithiasis.

Adult↗
PubMed1988

[So-called "renal" idiopathic hypercalciuria most often has a dietary origin].

Among renal stone formers with idiopathic hypercalciuria, patients who remain hypercalciuric despite low calcium intake have often been regarded as having a primary renal leak of calcium, i.e. renal hypercalciuria. However, at any given intake of calcium, dietary factors other than calcium can generate hypercalciuria, e.g. high intakes of sodium, of animal protein or of carbohydrates, or obesity itself. Thus, the incidence of renal hypercalciuria among stone formers has probably been overestimated. To address this issue, the aforementioned dietary and/or metabolic factors have been evaluated in 51 stone formers with idiopathic hypercalciuria refractory (i.e. U-Ca. V greater than 250 mg/24 h) to 5 days on low calcium intake (max. 400 mg/day). In 15 patients (all had U-Na. V greater than 200 mmol/24 h), U-Ca.V was within the 95% confidence limits of a nomogram U-Ca.V versus U-Na.V, suggesting that their idiopathic hypercalciuria was related, at least in part, to the high sodium intake. 7 patients had severe hyperuricosuria (greater than 1 g/24 h) suggesting high animal protein intake. 20 patients were obese (greater than 120% ideal weight) with (7 cases) or without (13 cases) concomitant fasting hyperinsulinemia (greater than 18 microU/ml). In addition, a careful retrospective analysis of intravenous pyelograms disclosed medullary sponge kidneys in 8 cases which had remained undiagnosed so far; in one of them histological confirmation was obtained after surgical removal of a renal pole and a radiologico-histological comparison. Thus, only 14 out of 51 patients had an otherwise unexplained idiopathic hypercalciuria on low calcium intake.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium↗
PubMed1988

Characterization of the thyroid microsomal antigen, and its relationship to thyroid peroxidase, using monoclonal antibodies.

MAb directed to the thyroid microsomal antigen have been developed. All bound to 101- and 107-kD bands in Western blot analysis using thyroid microsomal fraction as antigen. The MAb also bound to microsomal proteins immunoprecipitated by serum from patients having a high titer of anti-microsomal antibody but no antibodies to thyroglobulin or thyrotropin-stimulating hormone receptor. The pattern of binding was related to the amount of reducing agent. The 101- and 107-kD bands were increased by addition of dithiothreitol whereas, in its absence, numerous bands of higher molecular weight were present, suggesting a multimeric protein structure. Despite the inability to immunoprecipitate thyroid peroxidase (TPO) enzymatic activity, the MAb bound intensively in Western blot to denatured purified hog TPO and to denatured immunopurified human TPO. Trypsin digestion of the 101-107-kD antigen produced a doublet of 84-88 kD that was still immunoreactive with MAb. One of five polyclonal sera tested (with a microsomal antibody titer greater than 1/20,480 measured by the tanned red cell hemagglutination technique) also recognized the 84-88 kD trypsin fragments. Addition of V8 protease led to a disappearance of the 107-kD protein, but not the 101-kD protein, proving that this antigen is formed by two different polypeptides. The MAb bound strongly to thyroid epithelium, whereas binding to papillary carcinoma was absent or low and moderate for follicular and Hurthle cell carcinoma. This study indicates that the thyroid microsomal antigen and TPO are identical and are constituted of two different polypeptides. On SDS-PAGE the antigen appears as two contiguous bands which share common epitopes but are not identical, as proven by their size and difference in susceptibility to proteolytic digestion. The immunoreactivity of the molecule is highly dependent on a trypsin-sensitive site, which appears important in the recognition of the antigen by polyclonal sera and may have biological importance. The expression of microsomal antigenicity is variable among various thyroid carcinomas.

Antibodies, Monoclonal↗
PubMed1987

Dietary factors and medullary sponge kidneys as causes of the so-called idiopathic renal leak of calcium.

Out of 89 stone formers with idiopathic hypercalciuria, 51 remained hypercalciuric on a low calcium diet over 5 days: a renal leak of calcium could thus have been suspected in them. Dietary factors such as high sodium or high animal protein intake, and metabolic factors such as obesity with or without hyperinsulinemia, which all might account for the hypercalciuria of these patients, have been evaluated. This evaluation revealed conditions known to be associated with hypercalciuria in 37 of these 51 patients: 15 had hypercalciuria related to a high sodium intake, 7 had severe hyperuricosuria (greater than 1 g/24 h) reflecting a high animal protein intake, 20 were obese (greater than 120% of ideal weight) with (7 cases) or without (13 cases) concomitant high fasting plasma level of insulin (greater than 18 microU/ml). A careful retrospective analysis of the intravenous pyelograms disclosed medullary sponge kidneys in 8 cases which had remained undiagnosed so far. One of them was studied histologically. Only 14 out of 51 patients had an otherwise unexplained hypercalciuria on a low calcium diet. It is concluded that dietary causes appear to play a key role in 'idiopathic' hypercalciuria, that the incidence of a primary renal leak of calcium among idiopathic stone formers is much smaller than initially thought, and that this condition can hide unrecognized medullary sponge kidneys.

Calcium↗
PubMed1987

Characterization and isolation of thyroid microsomal antigen.

We investigated the structure of the 107-kD thyroid protein recognized as microsomal antigen. Solubilized microsomes were incubated with affinity gels consisting of IgG, from thyroiditis patients or controls, linked to Reacti-gel. Eluates were analyzed by SDS polyacrylamide electrophoresis and Western blot. 107- and 101-kD proteins were augmented in eluates from gels containing patient IgG and had microsomal antigenicity. In a Western blot of microsomes run under unreduced conditions, poorly defined large proteins were identified by antibody. When eluted electrophoretically and reanalyzed in reducing conditions, they demonstrated the 107-kD antigen. The 107-kD protein identified in reducing conditions was extracted and reanalyzed under nonreducing conditions. Large molecular mass proteins were then observed. On two-dimensional electrophoresis, a 107-kD antigen was isolated with isoelectric point of 7.0. The microsomal antigen may be complexes or multimers of a 107-kD peptide with isoelectric point of 7.0.

Antigens↗
PubMed1987

Isolation of a complementary DNA clone for thyroid microsomal antigen. Homology with the gene for thyroid peroxidase.

The thyroid microsomal antigen (MSA) in autoimmune thyroid disease is a protein of approximately 107 kD. We screened a human thyroid cDNA library constructed in the expression vector lambda gt11 with anti-107-kD monoclonal antibodies. Of five clones obtained, the recombinant beta-galactosidase fusion protein from one clone (PM-5) was confirmed to react with the monoclonal antiserum. The complementary DNA (cDNA) insert from PM-5 (0.8 kb) was used as a probe on Northern blot analysis to estimate the size of the mRNA coding for the MSA. The 2.9-kb messenger RNA (mRNA) species observed was the same size as that coding for human thyroid peroxidase (TPO). The probe did not bind to human liver mRNA, indicating the thyroid-specific nature of the PM-5-related mRNA. The nucleotide sequence of PM-5 (842 bp) was determined and consisted of a single open reading frame. Comparison of the nucleotide sequence of PM-5 with that presently available for pig TPO indicates 84% homology. In conclusion, a cDNA clone representing part of the microsomal antigen has been isolated. Sequence homology with porcine TPO, as well as identity in the size of the mRNA species for both the microsomal antigen and TPO, indicate that the microsomal antigen is, at least in part, TPO.

Amino Acid Sequence↗
PubMed1987

Antibodies against denatured and reduced thyroid microsomal antigen in autoimmune thyroid disease.

Different antigenic determinants on thyroid microsomal antigen (MAg) could induce different antibodies, which, in turn, could have differing importance in the pathogenesis of autoimmune thyroid disease. In this study we demonstrated three types of microsomal antibodies (MAbs) present in serum of patients with autoimmune thyroid disease by Western blot analysis. These MAbs reacted with native, denatured, and denatured and reduced MAg. Methods for detecting the MAbs were developed, and the clinical significance of these Abs was analyzed in 197 patients with thyroid disorders. For measurement of Ab against native and denatured MAg, an enzyme-linked immunosorbent assay, in which wells were coated with untreated or sodium dodecyl sulfate-denatured MAg, was used. For measurement of Ab against denatured and reduced MAg, 6% SDS-polyacrylamide gel electrophoresis followed by Western blot analysis was used. Native MAb enzyme-linked immunosorbent assay values correlated highly with microsomal hemagglutination titers, but patients with high titers of Ab against native MAg did not necessarily have Ab against denatured MAg or reduced MAg. Abs against denatured MAg or denatured and reduced MAg were found in patients with Hashimoto's disease (28.8% and 13.6%) and Graves' disease (22.4% and 11.2%). The percentage of patients with positive denatured and reduced MAb was higher in Graves' disease patients who had a longer sick interval or who developed hypothyroidism after radioiodine treatment. This study provides the first clear demonstration that MAbs are heterogeneous. The data suggest that antibodies against denatured or denatured and reduced MAg may be related to destruction of the thyroid gland.

Autoantibodies↗
PubMed1986

[Pyridoxine can normalize oxaluria in idiopathic renal lithiasis].

Pyridoxine (vitamin B6), given to patients with primary hyperoxaluria of type I, generally leads to a decrease in urinary excretion of oxalate owing to stimulation of conversion of glyoxylate to glycine instead of oxalate. It is not known, however, whether pyridoxine would equally influence hyperoxalurias of other origins, e.g. idiopathic or enteric. Two groups of patients were therefore given pyridoxine orally for 2 months (300 mg/d). Group 1 consisted of 10 idiopathic stone formers with mild hyperoxaluria of unknown origin. Group 2 consisted of 4 patients with enteric hyperoxaluria after intestinal bypass surgery. As a mean, enteric hyperoxaluria was not influenced by vitamin B6, which suggests that this disorder is the consequence of intestinal hyperabsorption of oxalate rather than of glyoxylate. In contrast, idiopathic hyperoxaluria was influenced by vitamin B6: urinary excretion of oxalate decreased in 8 patients out of 10 and became normal in 7. However, two patients did not respond to pyridoxine; both had concomitant severe hyperuricosuria (greater than 1 g/24 h), an observation suggesting that in these cases hyperoxaluria was of dietary origin. Four of the patients whose urinary excretion of oxalate became normal while on pyridoxine were followed up for 8 to 36 months after treatment: in all of them oxaluria remained normal. One whose oxaluria had returned to the upper normal limit was retreated after 2 years and again displayed a fall in urinary oxalate. It is concluded that pyridoxine given to idiopathic hyperoxalurics may correct the disorder, as in primary hyperoxaluria of type I; this is not the case in enteric hyperoxaluria. The mechanisms governing this sensitivity to vitamin B6 remain to be clarified.

Adult↗
PubMed1986

Anticystinuric effects of glutamine and of dietary sodium restriction.

We studied four patients with cystinuria to assess the effects of glutamine and dietary sodium on the urinary excretion of dibasic amino acids. In Patient 1, at an ad libitum dietary sodium intake of about 300 mmol per day, oral administration of glutamine led to reproducible and marked anticystinuria and antiornithinuria, whereas the excretion of lysine and arginine was not significantly affected. In Patient 2, at an ad libitum dietary sodium intake of about 150 mmol per day, no effect of glutamine could be demonstrated in studies lasting up to three weeks. Since the principal difference between Patients 1 and 2 was their dietary intake of sodium, Patient 3 was studied during dietary sodium intakes of 150 and 300 mmol per day. His cystine excretion was found to be higher at 300 than at 150 mmol per day. Glutamine suppressed his cystine excretion at a sodium intake of 300 mmol per day but had no effect at 150 mmol per day. When the effect of a further reduction in sodium intake alone was studied in a fourth patient, a decrease of 150 to 50 mmol per day was found to reduce cystine excretion markedly within 17 days. The low-sodium diet alone also reduced the excretion of lysine, arginine, and ornithine. We conclude that glutamine may reduce the excretion of dibasic amino acids at a high sodium intake but not at an intake of about 150 mmol per day. However, since a sodium-dependent excretion of the dibasic amino acids occurs at an intake down to about 50 mmol of sodium per day, dietary restriction of sodium can provide a safe approach to the treatment of cystinuria.

Administration, Oral↗
PubMed1986

[Indication of the urinary citrate levels in idiopathic renal calculosis].

The reported incidence of hypocitraturia among stone formers (SF) varies between 15 and 50%. It is not known whether this incidence depends on the subtype of SF. The recent simplification of the method of measurement of U-citrate (Boehringer-Mannheim kit) led us to address this issue in 118 male idiopathic (I) SF, with either idiopathic hypercalciuria of the renal (n = 6), absorptive (n = 19) or dietary (n = 41) type, or with normocalciuria (n = 52). Results were compared with those of 42 normal male volunteers. 9 patients had hypocitraturia (less than 215 mg/24 h), all of whom belonged to the group of normocalciuric ISF; only this group of patients had mean U-citrate X V significantly lower than controls (p = 0.025). The cause of hypocitraturia in these patients remains unknown: there were no significant correlations between U-citrate X V and U-pH or blood HCO3 or Cl. Moreover, the patients with hypocitraturia had neither urinary infection nor signs of distal tubular acidification dysfunction as assessed by fasting morning urinary pH. Extended to our whole population of ISF (250 patients) 75% of whom have idiopathic stone disease, it appears that measurement of U-citrate decreased the number of ISF without detectable disorder from 34 to 26, i.e. to 10% of the whole population of stone formers. Since hypocitraturia can easily be corrected by oral administration of citrate, routine measurement of U-citrate in normocalciuric ISF appears a promising method.

Calcium↗
PubMed1986

[Optimal dosage of chlorthalidone in the prevention of the recurrence of nephrolithiasis is 25 mg per day].

Thiazides are considered to be effective in preventing recurrence of various types of nephrolithiasis, but the optimum dosage has not been established. To address this issue, 5 idiopathic stone formers with hypercalciuria on low Ca diet received chlorthalidone (CT) in 3 different oral doses and were randomly assigned either to the sequence 25-50-100 mg/day or the reverse (2 months per dose, monthly blood and urine measurements). The anticalciuric effect of CT was significant only at 50 and 100 mg/day, at the expense of a dose-dependent decrease in U-citrate excretion. We also observed a dose-dependent decrease in blood levels of K, increases in those of HCO3 and urate, as well as in U-pH, a tendency for blood levels of Mg and U-oxalate excretion to fall, and no change in U-urate excretion. Therefore, to derive the optimal CT dose the Tiselius' risk index was applied, which is based on the values of urinary [Ca], [oxalate], [Mg], [citrate] and volume. CT produced a decrement in risk index which was similar at each of the doses tested. Thus, raising CT doses beyond 25 mg/day does not hold out the prospect of improved prophylaxis. This agrees with Ettinger's preliminary data (Urol. Res., 1984) showing a similar protective effect of CT at 25 and 50 mg/day despite the absence of a significant anticalciuric effect at 25 mg/day.

Calcium↗
PubMed1986

Oral versus intravenous AHPrBP (APD) in the treatment of hypercalcemia of malignancy.

Twenty patients with malignant hypercalcemia were treated with aminohydroxypropylidene bisphosphonate (AHPrBP, previously APD) a potent inhibitor of osteoclast-mediated bone resorption. To assess the efficacy of oral vs intravenous therapy, the patients were divided into two groups: group A received AHPrBP intravenously (30 mg/day), and group B received the drug orally (1200 mg/day) for 6 days. In both groups all the patients responded to AHPrBP with a rapid decrease in plasma calcium concentration after a mean time lag of 1 day. Within 9 days plasma calcium concentration fell from 3.42 +/- 0.13 (mean +/- SEM) to 2.26 +/- 0.13 mmol/l in group A and from 3.28 +/- 0.12 to 2.24 +/- 0.09 mmol/l in group B. There was no significant difference in plasma Ca level between both groups on days 4, 6, and 9, and plasma Ca was within the normal range in all patients on day 9. On both treatment regimens urinary calcium excretion fell dramatically and similarly. Plasma phosphate concentration decreased significantly on AHPrBP in both groups of patients, reaching values slightly below the normal range from day 4 to day 9. TmP/GFR decreased progressively on AHPrBP. However, this decrement was significant at day 6 only. Plasma parathyroid hormone concentration rose significantly in both groups from day 4 to day 9. We conclude that at the doses used in the present study treatment of tumor-induced hypercalcemia with AHPrBP is equally effective whether given orally or intravenously.

Administration, Oral↗
PubMed1986

Tubulopathy in nephrolithiasis: consequence rather than cause.

To address whether a renal tubular dysfunction is encountered in a particular patient subgroup with urolithiasis, the following parameters of tubular function were measured in urine taken in the morning from 214 stone formers after fasting: pH, excretion of lysozyme and gamma-glutamyl transferase (gamma-GT); fractional excretion (FE) of glucose, insulin, Mg, K, and HCO3 after an alkali loading; and the renal threshold for phosphate (TmP/GFR). The following diagnoses were made in the patient group: primary hyperparathyroidism (N = 8), medullary sponge kidneys (N = 21), hyperuricemia (N = 10), cystinuria (N = 2), struvite stone disease (N = 6), idiopathic hypercalciuria of the absorptive (N = 25), dietary (N = 69) or renal (N = 7) type, and normocalciuric idiopathic urolithiasis (N = 66). In 31% of the patients TmP/GFR was below 0.80 mmole/liter and in 13% of the patients, FE HCO3 after alkali loading was above normal. Urinary excretion of lysozyme and that of gamma-GT both were elevated in 17% of the patients. FE glucose, FE insulin, FE Mg, and FE K were elevated in 8, 9, 3, and 7% of the patients, respectively. This study demonstrates that a significant number of stone formers present with signs of renal tubular dysfunction, primarily involving the proximal tubule since apparent leaks of phosphate and of bicarbonate were most frequently encountered. The defects were not specific for a given etiologic group of patients; on the other hand, occurrence was related to the presence of large stones in the pyelocaliceal system at the time data were gathered. Taken together these data suggest that the tubulopathy in nephrolithiasis is the consequence rather than the cause of the stone.

Adolescent↗
PubMed1985

[Acute myocardial dysfunction in meningococcal septicemia].

A progressive myocardial dysfunction is known to occur in prolonged septic shock. The cases of two patients with acute meningococcal infection and Waterhouse-Friderichsen syndrome are reported. Hemodynamic measurements showed, in the early stage, the classical picture of hyperdynamic septic shock, with increased cardiac output and low systemic vascular resistances. However, rapidly progressive cardiac failure then occurred, with high filling pressures and low cardiac output. One patient went into irreversible shock. In the other the administration of inotropic agents was beneficial, with a slow but progressive improvement in left ventricular function over several weeks. Acute myocarditis has been frequently observed in patients with meningococcal infections. It is suggested that the acute myocardial failure observed in those circumstances is caused by the myocarditis.

Acute Disease↗
PubMed1985

[Tubular dysfunction in renal lithiasis: cause or consequence?].

To investigate whether overall tubular dysfunction is encountered in a particular subgroup of patients with urolithiasis, the following parameters of renal tubular function have been measured in fasting morning urine in 124 male stone formers: excretion of lysozyme and gamma-glutamyl transpeptidase (gamma-GT), fractional excretion (FE) or glucose, insulin, bicarbonate after an alkali load, and theoretical phosphate threshold (TmP/GFR). The following have been diagnosed: primary hyperparathyroidism (n = 3), medullary sponge kidneys (n = 5), hyperuricemia (n = 8), cystinuria (n = 1), struvite nephrolithiasis (n = 2), idiopathic hypercalciuria of the absorptive (n = 16), dietary (n = 46) or renal (n = 5) type, and normocalciuric idiopathic urolithiasis (n = 38). Urinary excretion of lysozyme and of gamma-GT were elevated in 14% and 21% of patients respectively; FE glucose and FE insulin were elevated in 6% and 8% of patients respectively. In 62% of the patients TmP/GFR was below 0.95 mmol/l and in 52% of the patients FE HCO3 after alkali load was above normal. The findings show that a large number of stone formers have signs of renal tubular dysfunction; apparent renal leaks of phosphate and of bicarbonate are the most frequently encountered defects; while they are not specific for a given etiologic group of patients, they have been found in each group. The latter observation suggests that nephrolithiasis itself can damage renal tubular function.

Adult↗
PubMed1985

Influence of the calcium content of the diet on the incidence of mild hyperoxaluria in idiopathic renal stone formers.

Urinary oxalate excretion was measured in 101 male idiopathic calcium (Ca) stone formers studied on 3 dietary conditions (free-choice, Ca-enriched, and low-Ca diet). The population consisted of 38 normocalciuric and 63 hypercalciuric patients. Mean oxalate excretion was similar in normocalciuric and in hypercalciuric patients, on free-choice as well as on Ca-enriched diet. In both conditions the incidence of hyperoxaluria (greater than or equal to 435 mumol/24 h) within each group of stone formers was also similar, ranging from 11 to 22%. On low-Ca diet, however, mean oxalate excretion increased significantly (p less than 0.01) in hypercalciurics but not in normocalciurics; on this diet, the incidence of hyperoxaluria was particularly high in the hypercalciurics (33%), compared with the normocalciurics (13%). On low-Ca diet, oxalate excretion was positively correlated with the estimated degree of intestinal absorption of calcium (p = 0.01). These results show that among idiopathic stone formers, mild hyperoxaluria is not a rare finding and that this disorder can be encountered in each group of patients; its incidence, however, is influenced by the calcium content of the diet. On a low-Ca diet, patients with intestinal Ca hyperabsorption are particularly prone to develop hyperoxaluria, an observation which leads to question the relevance of such a dietary advice unless oxalate intake is simultaneously reduced.

Adult↗