Utility of the carboxylesterase inhibitor bis-para-nitrophenylphosphate (BNPP) in the plasma unbound fraction determination for a hydrolytically unstable amide derivative and agonist of the TGR5 receptor.

The potent, functional agonist of the bile acid Takeda G-protein-coupled receptor 5 (TGR5), (S)-1-(6-fluoro-2-methyl-3,4-dihydroquinolin-1(2H)-yl)-2-(isoquinolin-5-yloxy)ethanone (3), represents a useful tool to probe in vivo TGR5 pharmacology. Rapid degradation of 3 in both rat and mouse plasma, however, hindered the conduct of in vivo pharmacokinetic/pharmacodynamic investigations (including plasma-free fraction (f(u plasma)) determination) in rodent models of pharmacology. Studies were therefore initiated to understand the biochemical basis for plasma instability so that appropriate methodology could be implemented in in vivo pharmacology studies to prevent the breakdown of 3. Compound 3 underwent amide bond cleavage in both rat and mouse plasma with half-lives (T(1/2)) of 39 + or - 7 and 9.9 + or - 0.1 min. bis(p-nitrophenyl) phosphate (BNPP), a specific inhibitor of carboxylesterases, was found to inhibit hydrolytic cleavage in a time- and concentration-dependent manner, which suggested the involvement of carboxylesterases in the metabolism of 3. In contrast with the findings in rodents, 3 was resistant to hydrolytic cleavage in both dog and human plasma. The instability of 3 was also observed in rat and mouse liver microsomes. beta-Nicotinamide adenine dinucleotide phosphate, reduced form (NADPH)-dependent metabolism of 3 occurred more rapidly (T(1/2) approximately 2.22-6.4 min) compared with the metabolic component observed in the absence of the co-factor (T(1/2) approximately 89-130 min). Oxidative metabolism dominated the NADPH-dependent decline of 3, whereas NADPH-independent metabolism of 3 proceeded via simple amide bond hydrolysis. Compound 3 was highly bound (approximately 95%) to both dog and human plasmas. Rat and mouse plasma, pre-treated with BNPP to inhibit carboxylesterases activity, were used to determine the f(u plasma) of 3. A BNPP concentration of 500 microM was determined to be optimal for these studies. Higher BNPP concentrations (1000 microM) appeared to displace 3 from its plasma protein-binding sites in preclinical species and human. Under the conditions of carboxylesterases-inhibited rat and mouse plasma, the level of protein binding displayed by 3 was similar to those observed in dog and human. In conclusion, a novel system has been devised to measure f(u plasma) for a plasma-labile compound. The BNPP methodology can be potentially applied to stabilize hydrolytic cleavage of structurally diverse carboxylesterase substrates in the plasma (and other tissue), thereby allowing the characterization of pharmacology studies on plasma-labile compounds if and when they emerge as hits in exploratory drug-discovery programmes.

Hypercalcemia and nephrocalcinosis in patients with congenital lactase deficiency.

We describe 11 infants with congenital lactase deficiency, whose age at diagnosis varied from 6 to 88 days. At the time of admission, 7 of 10 infants had hypercalcemia. Five of the seven infants for whom renal ultrasonography was performed at the time of diagnosis had medullary nephrocalcinosis. Hypercalcemia ceased within a week of the start of a lactose-free diet. At the time of reevaluation, at the ages of 2 to 10 years, one of the patients still had hypercalciuria and nephrocalcinosis was still present in 3 of 11 patients. The mechanism of hypercalcemia is unclear but may be related to metabolic acidosis or may be promoted by the lactose effect (i.e., by nonhydrolyzed lactose that has a direct enhancing effect on calcium absorption in the ileum).

Oral manifestations of familial hypophosphatemic rickets after phosphate supplement therapy: a review of the literature and report of case.

The patient was a seven-year-old boy with familial vitamin D-resistant hypophosphatemic rickets. His mother, and her mother, were also affected. Before phosphate treatment was introduced in the patient, an impaired incorporation of calcium, and its exchange with sodium, was thought to be the principal etiological factor in the formation of globules. Supplementation therapy then resulted in a less elevated Ca/P ratio in the root area of the affected teeth, as well as a cure for the boy's bone structure. What the therapy did not cure was the globular appearance of the dentin and the hypomineralized stripe of pulpal horn extending to the cusp tips, an apparent permanent outcome of the disease.

Underweight and overweight cases among the mentally retarded.

The body mass index (BMI) was calculated at the age of 20 for all the 132 survivors (83%) out of the 159 mentally retarded individuals born in 1966 in Northern Finland. Reliable information was acquired for 112 cases (84.8%). The mean BMI for these cases did not deviate significantly from that for an average Finnish population at age 20-29 years. It was found that 41.5% of the slightly retarded cases (IQ 35-70) and 28.6% of the seriously retarded ones (IQ less than 35) were of ideal weight (BMI 20-24), while 9.8% of all the retarded individuals were moderately obese (BMI greater than 30) and 7.1% seriously so (BMI greater than or equal to 32). Ninety-one per cent of the seriously obese cases lived with their parents and did not participate in any occupational therapy or work. A total of 29.5% of the mentally retarded subjects were underweight (BMI less than 20), a condition which would seem to be above all a problem for seriously retarded individuals and an obvious consequence of the different feeding and dietary problems connected with their multiple disabilities.

Coexistence of celiac disease and Down syndrome.

Three patients with Down syndrome and celiac disease were described. The incidence of celiac disease among patients with Down syndrome was calculated to be 8 per 1,000 live-born cases, a figure 20 times greater than in children without Down syndrome, indicating that it should be kept in mind when examining patients suffering from recurrent diarrhea and/or delayed puberty.

Development of bowel and bladder control in the mentally retarded.

For the mentally retarded, bowel and bladder control are important prerequisites for an independent life. A study of these functions was made in a cohort of children born in Northern Finland in 1966. Relevant data up to the age of 20 years were obtained for 105 of the 132 children with mental retardation (IQ less than 70) who were alive at that age. 80 per cent had attained bowel control at a mean age of 4.2 years, but 30.5 per cent were still encopretic at seven years, and 19 per cent at the age of 20 years. Full bladder control had been achieved by 62.9 per cent at the age of seven and by 82.9 per cent at the age of 20. It is concluded that systematic, appropriate toilet training could improve these figures markedly.

Coping with a coeliac diet after adolescence.

42 out of 45 adults aged 18-26 years (93%) diagnosed in childhood as having coeliac disease (CD) returned a questionnaire reviewing how they coped with the diet. 27 (64%) still continued to take a strict gluten elimination diet, five had failed completely and ten partly keep it up. Those adhering to the diet more often demonstrated a good knowledge of both CD and the diet. Neither age at the time of diagnosis nor social class, education of the patients or present social status was observed to have any positive correlation with compliance with the diet. The results indicate a need for more practical education of patients in terms of short refreshment courses.

Sternal abscess as a complication of BCG-revaccination.

A sternal abscess appeared 14 months after BCG revaccination of a 14-year-old girl. Culture taken from the abscess was positive for Mycobacterium bovis, which was identified as a BCG strain.

Neuropathology of Salla disease.

A neuropathological study was performed on two patients with Salla disease, one male and one female, from different families. They both died at the age of 41 years. Both patients showed increased excretion of free sialic acid in the urine, psychomotor retardation starting in the 1st year of life, ataxia and spasticity. Several family members of both families were affected with the same disease indicating the hereditary character of the disorder. The neuropathological investigation revealed strikingly similar changes in the two cases. Macroscopically the cerebral white matter was severely reduced. Histologically marked loss of axons and myelin sheaths was accompanied by pronounced astrocytic proliferation. The remaining axons frequently showed ovoid swellings surrounded by a myelin sheath. The reduction of the number of myelin sheaths seemed proportional to the numerical reduction of axons. Many cortical nerve cells displayed in relation to age an abnormal amount of lipofuscin. Neurofibrillary tangles were observed in nerve cells of the neo-cortex, nucleus basalis of Meynert and locus ceruleus. Cerebellum showed moderate loss of Purkinje cells. In the spinal cord axonal degeneration was observed in both ascending and descending tracts.

Mortality of mentally retarded children to 17 years of age assessed in a prospective one-year birth cohort.

Mortality among children with mental retardation (IQ less than 71) and mental subnormality (IQ: 71-85) up to the age of 17 years was studied in the 1966 one-year birth cohort of Northern Finland. The 12,058 liveborn children included 97 children, 8.0 per thousand, with severe mental retardation (IQ less than 50) and 68 children or 5.6 per thousand with mild mental retardation (IQ: 50-70). In addition, there were 162 children or 13.4 per thousand who were mentally subnormal (IQ: 71-85). The death rate among the children with mental retardation was 158 per thousand as compared to 22.6 per thousand among children with normal intelligence and was significantly higher among the mentally retarded of all ages. This is mainly an effect of the very high mortality in children with severe mental retardation, predominantly cases of Down's syndrome. It is concluded that mental retardation per se is not necessarily associated with an increased death rate, but the underlying etiology or additional complicating disorders may predispose the child to infections in particular, these being the leading cause of death among the mentally retarded children studied here.

Finnish type of sialic acid storage disease with sialuria (Salla disease): the occurrence and diagnostic significance of cytoplasmic vacuoles in blood lymphocytes.

In this study peripheral blood smears from 29 patients (17 males and 12 females; mean age 28 years, range 3-65 years) with a confirmed diagnosis of the Finnish type of sialic acid storage disease (FSASD) and 200 controls with mental retardation without any evidence of metabolic disease were examined for the presence of vacuolated lymphocytes. Urine samples were analysed by thin-layer chromatography for free sialic acid. Only 62% of the patients with FSASD had a clearly increased percentage of vacuolated lymphocytes (greater than normal mean + 2 s.d.). In thin-layer chromatography all the FSASD patients gave a positive test result. No false positive or negative results were obtained. Electronmicroscopical examination of peripheral blood lymphocytes demonstrated only non-specific changes in a few cells. Examination of peripheral lymphocytes for vacuoles is not a reliable screening test for FSASD. The screening method of choice is the analysis of free sialic acid by thin-layer chromatography.

Antipyretic effect of tenoxicam and paracetamol in febrile children.

The antipyretic activity of tenoxicam was compared with that of paracetamol. Thirty-eight inpatients aged between 6 months and 16 years, with a rectal temperature of above 38.5 degrees C, were divided into four groups. Patients received tenoxicam (0.3, 0.6 or 1.2 mg/kg) or paracetamol (10 mg/kg) in a single oral dose. Rectal temperatures were recorded before admission, 30 min and 1, 2, 3, 4, 5 and 6 h after administration of the drug. The fall in temperature was significant in the paracetamol group and in one tenoxicam group with a dose of 1.2 mg/kg. Doses of 0.3 and 0.6 mg/kg of tenoxicam had only a slight effect. It was concluded that tenoxicam has a slight antipyretic effect, but is not an alternative to paracetamol as an antipyretic drug in the treatment of fever in children.

Deoxycholic and sulpholithocholic acid concentrations in serum during infancy and childhood.

The concentrations of the two secondary bile acids (deoxycholic (DCA) and sulpholithocholic (SLCA) acid) were determined by radioimmunoassays in the serum of infants and children at ages ranging from 1 hour to 15 years. The same bile acids were measured also in the umbilical cord serum. The concentrations of the secondary bile acids in the serum of 1-hour old infants corresponded to those in the umbilical cord serum. Secondary bile acid serum concentrations were after the age of 7 days and up to the age of 3 to 6 months significantly lower than those in the umbilical cord serum. After the age of 6 months a significant increase in DCA serum concentrations could be shown. During the first 6 months of life DCA concentrations were clearly lower than those of SLCA. Our observations suggest that in the perinatal period DCA is mainly of maternal origin and that an alternate hepatic pathway may exist for the synthesis of lithocholic acid in early infancy.