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Biomedical subjects

L Monnens

Publications and source records attributed to L Monnens.

At least 19 recordsLinked to original sources

Congenital nephrotic syndrome: a novel phenotype of type I carbohydrate-deficient glycoprotein syndrome.

Type I carbohydrate-deficient glycoprotein (CDG) syndrome is a genetic multisystem disorder generally without overt renal problems. We report a neonate with neurological abnormalities and congenital nephrotic syndrome of diffuse mesangial sclerosis type. Serum transferrin isoelectric focusing showed the typical abnormalities of type I CDG syndrome. Normal transferrin focusing findings in other patients with similar renal problems excluded the possibility of a secondary biochemical phenomenon. The diagnosis of type I CDG syndrome was confirmed by demonstration of a deficiency of phosphomannomutase. No evidence of pontocerebellar atrophy was found in imaging or at autopsy. We conclude that congenital nephrotic syndrome may occur in type I CDG syndrome, and that this diagnosis should be considered in patients with congenital nephrotic syndrome. Absence of pontocerebellar atrophy does not exclude the diagnosis of type I CDG syndrome.

Congenital Disorders of Glycosylation

Supplementation of vitamin K in pregnant women receiving anticonvulsant therapy prevents neonatal vitamin K deficiency.

OBJECTIVE: The null hypothesis of this study is that extra vitamin K administered to pregnant women on a regimen of enzyme-inducing anticonvulsant therapy will not decrease the frequency of symptoms of vitamin K deficiency in their neonates. STUDY DESIGN: A multicenter case-control study was performed on 16 pregnant women on anticonvulsant therapy who received 10 mg of vitamin K1 daily from 36 weeks of pregnancy onward. Concentrations of PIVKA-II (protein induced by vitamin K absence for factor II) and of vitamin K1 were determined in cord blood and compared with those in 20 controls. RESULTS: In none of 17 cord samples was PIVKA-II detectable, compared with 13 of 20 in controls (chi 2, p < 0.001). Median cord vitamin K1 level was 530 pg/ml compared with below detection limit in most controls. CONCLUSIONS: Antenatal vitamin K1 treatment decreases the frequency of vitamin K deficiency in neonates of mothers on anticonvulsant therapy.

Anticonvulsants

Increased incidence of neonatal vitamin K deficiency resulting from maternal anticonvulsant therapy.

OBJECTIVE: The null hypothesis of our study is that the incidence of vitamin K deficiency in mother-infant pairs exposed to anticonvulsant drugs is not higher than in controls. STUDY DESIGN: In this multicenter observational case-control study, 25 pregnant women receiving anticonvulsant therapy and 25 pregnant controls were studied for PIVKA-II (protein induced by vitamin K absence of factor II) and vitamin K1 concentrations at 32 weeks' gestation and at delivery. RESULTS: PIVKA-II was detectable in 54% of cord samples of the anticonvulsant group and in 20% of controls (chi 2, p = 0.01). In both groups vitamin K1 cord blood levels were predominantly below the detection limit. Maternal vitamin K1 concentrations were lower in women with epilepsy than in controls (Wilcoxon's rank sum test, p < 0.05), but PIVKA-II was rarely present. CONCLUSIONS: The incidence of vitamin K deficiency is increased in neonates exposed to anticonvulsant drugs prenatally. Their mothers, however, are rarely vitamin K deficient.

Anticonvulsants

[2 children with stridor and a thymus in the posterior mediastinum].

Two infants are described with an inspiratory and expiratory stridor with apnea. X-ray examination showed a mass in the posterior mediastinum. For this reason both infants underwent a diagnostic thoracotomy because detailed study didn't resolve the problem. An aberrant localized thymus was found in both infants. In both infants, however, the complaints persisted after the operation. Both infants needed a second operation to relieve the stridor, which appeared to be due to (primary and secondary) tracheomalacia. This article describes shortly the embryology of the abnormally located thymus. The possibilities to diagnose a posterior mediastinal mass without thoracotomy are also described. Using magnetic resonance imaging (MRI), the posterior located thymus can be diagnosed noninvasively in most cases. The aberrantly positioned thymus should be included in the differential diagnosis of a posterior mediastinal mass, otherwise invasive methods are needed to come to the good diagnosis.

Apnea

[Good results of cyclophosphamide in steroid toxicity in the treatment of nephrotic syndrome caused by minimal-lesion glomerulopathy in childhood].

The effect of cyclophosphamide therapy was evaluated in the treatment of children with nephrotic syndrome due to minimal lesions. Most of the children, 37 out of 43, presented with frequent relapsing nephrotic syndrome. Cyclophosphamide was given in a dose of 3 mg/kg body weight/day for a period of 8 weeks. Two patients received two courses, one patient received three courses. Only one patient, who was steroid-resistant, did not respond to cyclophosphamide therapy (therapy was, however, stopped after 3 weeks because of haemorrhagic cystitis). 57% of the patients were still in remission after 18 months (n = 37) and 50% after 30 months (n = 34). A haemorrhagic cystitis developed in 3 patients and leucopenia in 2 patients. From this study, which confirms data reported in literature, it can be concluded that cyclophosphamide has a beneficial effect in children with minimal lesion nephrotic syndrome and steroid toxicity.

Adolescent

Acute renal failure in a neonate due to pelviureteric candidal bezoars successfully treated with long-term systemic fluconazole.

Systemic candidiasis with renal involvement is a rare but well-recognized complication during intensive care treatment in very-low-birth-weight infants. We report a term neonate who developed anuria associated with bilateral bezoar formation in the renal pelvis and candidemia. The treatment consisted of placement of a nephrostomy tube in the left kidney, short-term irrigation with amphotericin B and iv, and later, oral administration of fluconazole.

Acute Kidney Injury

Analysis of chromosome aberrations and sister chromatid exchanges in peripheral blood lymphocytes of newborns after vitamin K prophylaxis at birth.

In many countries vitamin K prophylaxis at birth is recommended to prevent bleeding in infants due to vitamin K deficiency. Because the incidence of clinical vitamin K deficiency is very low, such a vitamin K administration should be completely safe. However, an increase in sister chromatid exchanges in lymphocytes of fetal sheep 24 h after injection of vitamin K1 has been reported. Therefore, a study concerning genotoxicity of vitamin K1 in man was conducted. Sister chromatid exchanges and chromosome aberrations were analyzed in peripheral blood lymphocytes of six newborns 24 h after intramuscular administration of 1 mg vitamin K1 and in six control neonates. The mean number of sister chromatid exchanges per metaphase in the vitamin K group was 8.88 +/- 1.22 as compared with 9.05 +/- 1.14 in the control group (NS). The mean number of chromosome aberrations per 100 mitoses was 3.00 +/- 2.61 in the vitamin K group and 2.50 +/- 1.87 in the control group (NS). Vitamin K1 plasma concentrations ranged from 115 to 1150 ng/mL (255 to 2555 x 10(-9) M) in the supplemented group, a 5000-fold rise as compared with the control group (p less than 0.01). We did not find any evidence for genetic toxicity due to the administration of 1 mg vitamin K1 intramuscularly to the newborn child.

Case-Control Studies

Nephrosis in two siblings with infantile sialic acid storage disease.

The diagnosis of infantile sialic acid storage disease (ISSD) was established in two siblings on the basis of typical clinical signs and the biochemical findings of hyperexcretion and intracellular storage of free sialic acid. A severe, steroid resistant nephrosis occurred in both siblings. The activities of lysosomal enzymes, including sialidase, were normal. A combined detection method for sialic acids with Limax flavus agglutinin labelling and phosphotungstic acid staining showed severely alterated sialic acid components in epithelial kidney cells and indicate a causal relationship between the nephrosis and the underlying biochemical defect. Further observations of ISSD patients with renal involvement will prove if a separate nephropathic phenotype exists.

Carbohydrate Metabolism, Inborn Errors

Urinary excretion of prostaglandins during infancy and childhood: influence of age, sodium restriction and posture.

The influences of age, sodium restriction and posture on 24-hour urinary excretion of prostaglandin E2 (PGE2), prostaglandin F2 alpha (PGF 2 alpha), 6-keto-prostaglandin F1 alpha (6-keto-PGF 1 alpha) and thromboxane B2 (TXB2) were investigated in 111 healthy children and youngsters in the age between 1 day and 16 years. A considerable degree of variation was found in normal 24-hour urinary prostaglandin excretion in all age groups. There was no significant effect of age on the urinary excretion of prostaglandins when data were corrected for body surface area. In addition, sodium restriction and posture had no influence on the excretion of PGE2, PGF 2 alpha, 6-keto-PGF 1 alpha and TXB2. Our results indicate that in the first days of life the kidney already has the capacity to synthesize prostaglandins in amounts comparable to older children.

Adolescent

Evidence for a proximal site of action of atrial natriuretic peptide in man.

The site of action of atrial natriuretic peptides (ANP) in man remains uncertain. In this study the attention was focused on the proximal tubule. Three markers of the proximal tubular reabsorption were used as a tool: lithium, amino acids and beta 2-microglobulin. The reabsorption of these three substances was decreased during ANP infusions in 3 normal sodium-replete male volunteers. These findings suggest that ANP not only decreases distal sodium reabsorption, but also proximal fractional tubular sodium reabsorption in man.

Adult

Further analysis of the disturbed adrenocortical function in the cerebro-hepato-renal syndrome of Zellweger.

Plasma aldosterone, corticosterone, 11-deoxycorticosterone, progesterone, 17-hydroxyprogesterone, 11-desoxycortisol, cortisol and cortisone were determined simultaneously in small plasma samples obtained during an i.v. ACTH (Synacthen) stimulation test in five patients (age 4-7 years) with Zellweger syndrome. The response of all ACTH-dependent steroids to Synacthen was severely impaired in all patients, despite normal basal levels. It can be concluded that the biochemical defect in adrenal steroidogenesis causing the inadequate response to ACTH injection is located proximal to progesterone. We propose that the lack of responsiveness to ACTH is secondary to an abnormality of ACTH receptors on the adrenocortical cell. The extremely low levels of non-specific lipid transfer protein may be a contributing factor.

Adrenal Cortex

Three-point linkage analysis using multiple DNA polymorphic markers in families with X-linked nephrogenic diabetes insipidus.

The gene for X-linked nephrogenic diabetes insipidus (NDI), a disorder which, if untreated, causes severe dehydration, mental retardation, and possibly death in affected males, has been mapped recently to the Xq28 band through demonstration of linkage to the DX552 locus and other DNA markers (N. Knoers et al., 1987, Cytogenet. Cell Genet. 46:640; M. Kambouris et al., 1987, Cytogenet. Cell Genet. 46:636). Linkage studies in 11 families with NDI have enabled us to map the NDI gene between closely linked flanking markers in the Xq28 region and to obtain the following gene order: centromere-F9-DXS98-F8/CBD,CBP-DXS52/NDI-DXS134- telomere. These results have implications for presymptomatic and prenatal diagnosis of NDI and should also improve the prospects for identifying the fundamental gene defect underlying this disorder.

Chromosome Deletion

[The De Barsy syndrome].

De Barsy syndrome is defined by the combination of a progeroid aspect, cutis laxa, cornea clouding, growth retardation, mental retardation and athetoid movements. The clinical symptoms of a male infant are described and compared with all other cases reported in literature. The aetiology of this syndrome is unclear; inheritance is probably autosomal recessive.

Athetosis

Plasma concentrations of vitamin K1 and PIVKA-II in bottle-fed and breast-fed infants with and without vitamin K prophylaxis at birth.

Plasma vitamin K1 and proteins induced by vitamin K absence (PIVKA) were assayed simultaneously 1-4 days and 29-35 days after delivery in three groups of infants: breast-fed not receiving vitamin K at birth (n = 12), bottle-fed without vitamin K administration at birth (n = 7) and breast-fed receiving 1 mg vitamin K1 administered by intramuscular injection at birth (n = 13). The bottle-fed infants had a significantly higher vitamin K1 plasma level than breast-fed infants who did not receive vitamin K1 at birth. Extremely high levels of vitamin K were obtained 1-4 days after intramuscular administration. At the age of 1 month, breast-fed infants had the same plasma vitamin K1 concentration whether or not they had received vitamin K1 supplements. Decarboxy prothrombin (PIVKA-II) a reliable indicator of biochemical vitamin K deficiency, was found in 5 out of 12 breast-fed and in 2 out of 6 bottle-fed infants who had not received supplemental vitamin K1 after birth. In a separate study, we followed up to 90 days after birth a larger group if infants. PIVKA-II was found with significantly greater frequency in breast-fed infants receiving no vitamin K than in breast-fed infants receiving 1 mg vitamin K intramuscularly at birth, or in bottle-fed infants without extra vitamin K1. These data form a strong argument for routine vitamin K prophylaxis after birth for all breast-fed infants. The optimum dose and manner of administration require further study.

Biomarkers