Barrett's esophagus in children with cystic fibrosis: not a coincidental association

Barrett's esophagus (BE) is a premalignant condition, and a recognized complication of severe gastroesophageal (GE) reflux. Children with cystic fibrosis (CF) have a marked predilection to develop GE reflux, but Barrett's esophagus is one complication of GE reflux not previously described in CF. We describe in detail two adolescents with CF who were found to have Barrett's esophagus, and mention three other cases. The presence of Barrett's esophagus in CF patients may be missed because GE reflux is often relatively silent in CF, because patients may consider mild upper gastrointestinal (GI) symptoms as "part of CF," and because of the nature of Barrett's epithelium itself. Upper gastrointestinal (GI) endoscopy with documentation of landmarks and multiple targeted biopsies should be performed in children with CF with even mild symptoms of GE reflux or an abnormal 24 h intra-esophageal pH study. Any biopsies containing columnar epithelium should be stained with Alcian blue at pH 2.5 to look for goblet cell metaplasia, i.e., Barrett's esophagus. Children with CF may be a high-risk group for development of Barrett's esophagus and its complications, especially given the increased survival in CF.

Barrett's esophagus in children with cystic fibrosis: not a coincidental association

Barrett's esophagus (BE) is a premalignant condition, and a recognized complication of severe gastroesophageal (GE) reflux. Children with cystic fibrosis (CF) have a marked predilection to develop GE reflux, but Barrett's esophagus is one complication of GE reflux not previously described in CF. We describe in detail two adolescents with CF who were found to have Barrett's esophagus, and mention three other cases. The presence of Barrett's esophagus in CF patients may be missed because GE reflux is often relatively silent in CF, because patients may consider mild upper gastrointestinal (GI) symptoms as "part of CF," and because of the nature of Barrett's epithelium itself. Upper gastrointestinal (GI) endoscopy with documentation of landmarks and multiple targeted biopsies should be performed in children with CF with even mild symptoms of GE reflux or an abnormal 24 h intra-esophageal pH study. Any biopsies containing columnar epithelium should be stained with Alcian blue at pH 2.5 to look for goblet cell metaplasia, i.e., Barrett's esophagus. Children with CF may be a high-risk group for development of Barrett's esophagus and its complications, especially given the increased survival in CF.

Allelic association and linkage studies in Wilson disease

We have studied 21 families with Wilson disease (WND), using restriction fragment length polymorphisms (RFLPs) in the 13q14.3 region, to measure linkage of these markers to the disease locus. In addition to previously described markers, we include linkage data for a newly isolated marker (D13S86) and an established marker (D13S56), which were previously not placed on the genetic map in the region of the WND locus. Our data, including those from two recombinant families, support the location of WND between the markers D13S31 and D13S59. We have examined the distribution of marker alleles at the loci studied and have found that D13S31 and D13S228, and associated microsatellite marker, show a non-random distribution on chromosomes carrying the WND mutation. The significant linkage disequilibrium indicates that these two markers must be close to the WND locus.

Oral zinc therapy in the treatment of alpha-mannosidosis

Human alpha-mannosidosis is a lysosomal storage disorder characterized by mental retardation, dysostosis multiplex, and hepatosplenomegaly. Deficiency of the enzyme leads to accumulation of mannose-rich glycoconjugates in tissues. Zinc sulphate has been shown to stimulate alpha-mannosidase activity in vitro. Oral zinc therapy was attempted on a 4-year-old boy with alpha-mannosidosis for 3 years. After almost 10 years of follow-up on and off zinc therapy, we must conclude that oral zinc does not substantially affect the clinical course of alpha-mannosidosis.

Pseudomonas aeruginosa colonization of the gastrointestinal tract in patients with cystic fibrosis

Respiratory and fecal specimens from 111 patients with cystic fibrosis (CF) were cultured on 394 occasions to determine which site Pseudomonas aeruginosa colonizes first. By an enrichment and selection culture technique, P. aeruginosa was recovered from fecal cultures in 21 (42%) of 50 respiratory tract-positive patients but from only 3 (6.3%) of 48 respiratory tract-negative patients and from 1 (2.2%) of 45 control subjects. In 4 (22%) of the 18 patients who became culture-positive during the study, P. aeruginosa was recovered from a fecal specimen before respiratory colonization. Only 1 of these 4 became persistently colonized with P. aeruginosa in the respiratory tract; however, the serotype of the respiratory isolate was different from that of the fecal isolate. P. aeruginosa is recovered rarely from the feces of patients with CF who are culture-negative in the respiratory tract. In patients with CF, primary colonization with P. aeruginosa probably occurs in the respiratory tract.

Systemic hemodynamic and hepatic microvascular responses to a 33% blood volume exchange with whole blood, stroma-free hemoglobin, and oxypolyhemoglobin solutions

Little is known about the microvascular effects of blood replacement solutions. This study was undertaken to develop an animal model suitable for studies of the microcirculatory effects of such solutions and to investigate microvascular responses to isovolemic transfusion with stroma-free hemoglobin (SFH), whole donor blood, or a new potential blood substitute solution containing oxypolyhemoglobin (OPH) as an oxygen carrier. Hamster livers were exposed and the microcirculation studied using intravital epifluorescent video microscopy. 33% blood volume replacement with SFH elevated systemic blood pressure by 25 Torr. Accompanying this increase in pressure was a 36% decrease in sinusoidal blood flow velocity and a 10% decrease in terminal hepatic venular diameters. Terminal portal venular diameters did not change. Decrease in liver sinusoidal perfusion was not due to neutrophil mediated injury, as myeloperoxidase activity in jejunum, liver, kidney, and lung remained unchanged. The reduction in perfusion was likely due to systemic vasoconstriction produced by SFH. In contrast, transfusion with whole blood did not change any of the measured parameters showing the excellent stability of the model. OPH transfused animals exhibited only a small 10 Torr transient increase in MAP 15 min post-transfusion. By 30 min MAP returned to the pre-infusion value. No significant changes were observed in either venular diameters or sinusoidal velocities in this group of animals. These results demonstrate suitability of this model for studies of the microcirculatory and hemodynamic effects of blood replacement solutions. Furthermore, OPH solution produced only minor transient disturbances in microvascular and systemic parameters.

Stereoselective inhibition of renal organic cation transport in human kidney

Amantadine was found to be concentrated by human cortical slices, with apparent Km and Vmax values of 187 +/- 11 microM and 1.37 +/- 0.28 nmol mg-1 min-1 respectively (mean +/- s.e. mean, n = 4). Addition of quinine (8S, 9R-(-)-isomer) or quinidine (8R, 9S-(+)-isomer) competitively inhibited this accumulation (apparent Ki values of 261 +/- 44 (n = 4) and 586 +/- 68 microM (n = 3), respectively). The stereoselectivity of this inhibition is the reverse of that seen with respect to the renal clearances of the diastereoisomers.

Interference with renal organic cation transport by (-)- and (+)-nicotine at concentrations documented in plasma of habitual tobacco smokers

Nicotine is the principal psychoactive Nicotiana alkaloid in tobacco. In the present study, we used amantadine as a marker and investigated the potential ability of nicotine and cotinine to interfere with renal organic cation transport in vitro. [3H]Amantadine is concentrated actively by isolated proximal tubules, distal tubules and cortical slices. In proximal tubules, the addition of (-)- or (+)-nicotine (0.1-100 microM) facilitated amantadine (10 microM) accumulation. Apparent Km for amantadine uptake was decreased by a clinically relevant concentration of (-)- and (+)-nicotine (0.4 microM), from 78 +/- 2 to 52 +/- 2 and 61 +/- 5 microM, respectively (mean +/- S.E.M., P less than .05), whereas Vmax was not altered (6.6 +/- 0.1 to 6.3 +/- 0.1 and 6.5 +/- 0.2 nmol/mg/min). The addition of (-)-cotinine (0.4-100 microM) also facilitated amantadine uptake, but with lesser efficacy. Possible mechanisms underlying the present enhancement of uptake include facilitation of amantadine influx and/or attenuation of efflux. Efflux data indicate a prominent hindrance of amantadine egress from preloaded tubules in the presence of 0.4 microM (-)- and (+)-nicotine (51 +/- 4 to 32 +/- 8 and 27 +/- 4 pmol/mg/30 sec, P less than .05) and are supportive of the latter notion. In distal tubules, (-)- or (+)-nicotine produced inhibition only a high concentrations (greater than or equal to 100 microM). Km was increased by 400 microM (-)- and (+)-nicotine from 76 +/- 5 to 124 +/- 9 and 116 +/- 17 microM, and Vmax was moderately decreased from 3.4 +/- 0.5 to 3.0 +/- 0.4 and 3.0 +/- 0.4 nmol/mg/min (P less than .05). The incorporation of (-)-cotinine did not alter amantadine uptake. Enhancement of uptake by (-)- or (+)-nicotine was absent in cortical slices, in which tubular luminal transport has ben proposed to be insignificant, and only low affinity inhibition was apparent. The present data indicate potent interference of renal proximal tubular transport of amantadine by nicotine at concentrations equivalent to those documented in plasma of habitual tobacco smokers and suggest potential alterations in renal organic cationic drug elimination in these subjects.

Pharmacokinetic studies in the rat on a o-raffinose polymerized human hemoglobin

We have studied the plasma half-life (T 1/2), oxygen-binding affinity (P50), organ distribution, and excretion of the individual molecular weight (MW) components of human hemoglobin polymerized with periodate-oxidized, ring-opened raffinose (oR poly-Hb), following transfusion in the rat. The model was an isovolemic 50% exchange transfusion in the conscious, chronically catheterized rat. Total plasma Hb levels yielded a (T 1/2) of 10 to 11 hr for oR poly-Hb. The T 1/2 values of individual MW components of the poly-Hb as determined by size-exclusion HPLC were approximately: 4 hr for the monomeric fraction (Hb)1, 9 hr for the dimer (Hb)2, and 15 hr for the fraction representing trimers to nanomers (Hb)3-9. The P50 values of plasma samples containing oR poly-Hb (collected from 0-24 hr after exchange) remained unchanged at 28 +/- 3 mmHg. oR stabilized and polymerized Hb were not excreted via the kidneys. Hepatic and renal distribution as well as plasma and renal clearance were determined by liquid scintillation counting using individual tritium [3H] labelled MW components purified from [3H]-oR poly-Hb: (Hb)1/2, (Hb)1, (Hb)2, (Hb)3&4, and (Hb) greater than 9. In kidney, uptake (determined by the relative concentration of radioactivity) decreased with increasing MW of the labelled component. Conversely, in liver, uptake increased with increasing MW. Plasma and renal clearance results were consistent with those obtained by HPLC analysis. Hematocrit levels returned from a 20% post-transfusion level to normal pre-transfusion levels (44%) within 10 days after the exchange.

Hepatic dysfunction in Alström disease

Alström disease is a rare disorder; less than 20 cases have been reported. An 11-year-old girl is described with this condition. She has pigmentary retinopathy, sensory neural deafness, obesity, Type II diabetes mellitus, hyperlipidemia, and acanthosis nigricans. However, in addition she developed hepatic dysfunction, pathologically similar to chronic active hepatitis. This may be a further, previously undescribed systemic manifestation of Alström disease.

Differential effects of histamine H2 receptor antagonists on amantadine uptake in the rat renal cortical slice, isolated proximal tubule and distal tubule

The interaction between amantadine and two histamine receptor antagonists was examined in the rat kidney. Amantadine (10 microM, 30 sec) was actively accumulated by cortical slices (slice/medium ratio = 0.4 +/- 0.3 [3.3 +/- 0.3 at 4 min], mean +/- S.E.M.), isolated proximal tubules (tubule/medium ratio = 35 +/- 1) and distal tubules (tubule/medium ratio = 19 +/- 2). In cortical slices, low cimetidine concentrations facilitated amantadine accumulation, whereas higher concentrations produced inhibition. Uptake in proximal tubules was enhanced by cimetidine and reached a maximum at approximately 100 microM. Cimetidine (20 microM) decreased the apparent Km (88 +/- 5 to 55 +/- 3 microM, P less than .005) without altering Vmax (6.8 +/- 0.5 to 5.8 +/- 0.6 nmol/mg/min). Conversely, cimetidine did not enhance uptake in distal tubules but elicited competitive inhibition at concentrations greater than 1 mM. Although this may partially delineate the differences observed between the cortical slice and proximal tubule data, such a discrepancy may also implicate additional sites of interaction in other segments of the cortical nephron and/or cimetidine inhibition of the relatively more significant luminal amantadine efflux in the proximal tubules. Ranitidine did not enhance amantadine accumulation but produced inhibition at high concentrations. In proximal and distal tubule preparations, ranitidine (10 mM) increased Km from 86 +/- 7 to 121 +/- 8 and 95 +/- 5 to 160 +/- 10 microM, respectively (P less than .05), whereas Vmax was not changed (8.9 +/- 0.7 to 7.9 +/- 0.8 and 4.3 +/- 0.1 to 3.8 +/- 0.2 nmol/mg/min, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Biochemical investigation of a child with molybdenum cofactor deficiency

A girl aged eight months, who presented with developmental delay and dislocated optic lenses, was diagnosed as having combined sulfite oxidase and xanthine dehydrogenase deficiencies consistent with molybdenum cofactor deficiency. The diagnosis was confirmed by demonstrating the absence in urine of urothione, a molybdenum cofactor metabolite. Prenatal diagnosis excluded the disease in the mother's second pregnancy. A summary of an in vitro study of molybdenum cofactor synthesis in the patient is given.

Stereoselective inhibition of amantadine accumulation by quinine and quinidine in rat renal proximal tubules and cortical slices

The renal organic cation transport system was examined. The accumulation of a nonchiral cation, amantadine, by rat renal proximal tubules and cortical slices was investigated, together with the effects of two diastereoisomers, quinine and quinidine. The proximal tubules actively concentrated amantadine with a tissue/medium ratio of 96.3 +/- 1.7 (mean +/- S.E.M., n = 18). Apparent Km was 85 +/- 2 microM and Vmax was 8.0 +/- 0.2 nmol/mg of tubular protein per min. Amantadine accumulation was inhibited competitively by quinine and quinidine with Ki values of 32 +/- 3 and 84 +/- 11 microM, respectively (n = 4). Amantadine was also concentrated by renal cortical slices with tissue/medium ratio of 3.3 +/- 0.3 (n = 4). Apparent Km and Vmax were 94.0 +/- 5.2 microM and 1.27 +/- 0.08 nmol/mg of tubular protein per min, respectively (n = 10). Quinine and quinidine again inhibited amantadine accumulation competitively by the slices, with Ki values of 368 +/- 28 and 780 +/- 84 microM, respectively (n = 4). A similar affinity (Km) for amantadine was observed in both preparations. However, the lower Vmax value in the slice system may be due to additional amantadine transport sites with lower capacity, lesser luminal accumulation and/or limited substrate(s) penetration in the cortical slices. In either preparation, quinine and quinidine functioned as competitive inhibitors and stereoselectivity was observed for the (-)-isomer, quinine, over the (+)-isomer, quinidine. Additional transport sites, reduced luminal substrate accumulation and/or diffusional restraints in the slices are also feasible mechanisms in explaining the differences in Ki values between the two preparations, and their relative contributions await further investigation.

Cardiomyopathy associated with nonendemic selenium deficiency in a Caucasian adolescent

We describe a girl aged 17 y who died after a cardiac arrest secondary to septic shock. At autopsy, the enlarged, soft, and flabby heart showed microscopic evidence of acute myocardial infarction, myocardial edema, myocardiocyte loss, replacement fibrosis in the interventricular septum, and right and left ventricular hypertrophic nucleomegaly. The pathological diagnosis was that of cardiomyopathy due to prolonged selenium deficiency. The patient had been on total parenteral nutrition for 17 mo, following extensive bowel resection for intractable pain, nausea, and vomiting caused by chronic idiopathic intestinal pseudoobstruction. Seven months before death, when severe biochemical selenium deficiency was diagnosed, supplemental selenium was added to the infusion, and plasma selenium concentrations increased. In long-standing selenium deficiency, sepsis may contribute the final insult to a damaged myocardium, triggering symptomatic cardiac failure and sudden death.

Estrogen-binding properties of rat serum alpha 1-fetoprotein and its isoforms. Investigation of the apparent non-integrality of sites on the unfractionated protein

Rat fetal serum alpha 1-fetoprotein (AFP), a heterogeneous glycoprotein, binds estrogens with high affinity but at a fractional number of sites even after treatment with charcoal (n = 0.6), which may mean 60% of the protein has 1 site and the remainder none. To investigate the origin of this fractional number of sites the "native" protein (purified by negative affinity chromatography) was further purified (step 1) and fractionated (step 2) into its two main charge variants (electrophoretically "slow" and "fast") by a two-step fast-protein liquid chromatography method. The binding parameters for estrone and estradiol-17 beta of the "native" and "repurified" proteins and of each charge variant were determined by equilibrium microdialysis. The molar extinction coefficient at 278 nm of each sample was also determined. (1) The "repurified" AFP and each charge variant had a number of binding sites for estrogens close to unity. This increase in the number of sites could neither be explained by the loss of a non-binding isoform (corresponding to 40% of the protein) during chromatography, nor by the existence of complex negative modulatory interactions between isoforms. (2) The affinities for estrogens of the "repurified" protein and the two charge variants were slightly decreased compared to that of "native" AFP, except that the "fast" form had the "native" protein's high affinity for estrone--but not for estradiol-17 beta. (3) The molar extinction coefficients at 278 nm of the "repurified" AFP and the isoforms were much lower than that of the "native" protein. These results suggest that the presence of (an) inhibitor(s) of estrogen binding on the "native" protein which is/are removed by the ion-exchange fast protein liquid chromatography (FPLC) column. A ligand absorbing at 278 nm, which may or may not be the inhibitor, is also removed. The isoform heterogeneity with respect to estrone binding is discussed.

The high incidence of valproate hepatotoxicity in infants may relate to familial metabolic defects

The incidence of fatal hepatic failure associated with valproic acid (VPA) therapy is highest in children under the age of three years, particularly in those with developmental delay. The pathogenesis of VPA hepatotoxicity is unclear but may relate to the accumulation of a toxic metabolite of VPA which impairs fatty-acid oxidation. We describe two unrelated infants with developmental delay who developed hepatic failure while receiving VPA. Siblings of both children subsequently developed hepatic steatosis and intractable seizures without being exposed to VPA. This suggests that the two children who developed liver failure when receiving VPA may have had a familial metabolic disorder. Familial metabolic disorders may account partly for the higher incidence of fatal hepatotoxicity described in infants receiving VPA.

Application of high-performance liquid chromatography for the study of the microheterogeneity changes of mouse alpha-fetoprotein in fetal development

Changes in the microheterogeneity of mouse alpha-fetoprotein (MAFP) during fetal development were investigated by high-performance liquid chromatography (HPLC). A total of six distinct isoforms (Iso-1, Iso-2, Iso-3, Iso-4, Iso-5, Iso-6) of the heterogeneous MAFP were resolved from mouse amniotic fluid (MAF). Analysis of MAF collected at various times revealed that these isoforms were accumulated at different stages of the fetal development.

Recovery of sperm production following the cessation of gossypol treatment: a two-centre study in China

A number of variables were investigated in 46 men who had stopped taking gossypol for their predictive association with the degree and time of recovery of spermatogenesis. Thirty-nine (87%) of the men were azoospermic at cessation of gossypol treatment. In those with sperm present the geometric mean concentration and total sperm count were 8.3 X 10(6)/ml and 30.7 X 10(6), respectively. Twenty-eight men (61%) recovered to a defined threshold of spermatogenic function (sperm concentration greater than or equal to 20 X 10(6)/ml), with a median recovery time of 1.1 years. However, 18 men (39%) had not recovered to this degree of spermatogenic function after a median follow-up of 1.9 years and, of these, 10 (22%) remained azoospermic. The influence of individual baseline variables on the time to defined recovery was examined using Kaplan-Meier curves for groups and their joint effect by Cox's regression model. The failure of recovery was strongly associated with longer treatment, greater total dose of gossypol, smaller testicular volume, elevated FSH concentrations and, to a lesser extent, with greater body weight.

Follow-up of men in the recovery period immediately after the cessation of gossypol treatment

Variables in 46 men who had stopped taking gossypol in two centres in China were investigated for their predictive association with the degree and time of recovery of spermatogenesis. Thirty-nine (87%) were azoospermic at cessation of gossypol treatment. In those with sperm present the geometric mean concentration and total sperm count were 8.3 x 10(6)/ml and 30.7 x 10(6), respectively. Twenty-eight (61%) recovered to a defined threshold spermatogenic function (sperm concentration greater than or equal to 20 x 10(6)/ml), with median recovery time 1.1 years. However, 18 men (39%) had not recovered after a median follow-up of 1.9 years and, of these, 10 (22%) remained azoospermic. The failure of recovery was strongly associated with longer treatment, greater total dose of gossypol, smaller testicular volume, elevated FSH concentrations and, to a lesser extent, with greater body weight.

Guanosine triphosphate cyclohydrolase I deficiency: early diagnosis by routine urine pteridine screening

A deficiency of hepatic guanosine triphosphate cyclohydrolase I is reported in a 4-month-old infant in whom positive results on a Guthrie phenylketonuria test in the neonatal period were found. Because of the significantly elevated serum phenylalanine levels a diagnosis of classical phenylketonuria was made, and dietary therapy was started. Urinary pteridine screening for cofactor variants, however, revealed extremely low levels of both neopterin and biopterin. This suggested the possibility of guanosine triphosphate cyclohydrolase I deficiency and led to additional confirmatory assays. Repeat urine, serum, and CSF pteridine profiles, combined with tetrahydrobiopterin-loading studies and the assay of guanosine triphosphate cyclohydrolase I activity in a liver biopsy, confirmed the defect. It is significant to note that the diagnosis was made before the onset of major clinical symptoms. This case illustrates the need for routine cofactor variant screening of all infants in whom hyperphenylalaninemia is diagnosed in the neonatal period.

Biochemical and histologic pathology in an infant with cross-reacting material (negative) pyruvate carboxylase deficiency

An infant with the acute neonatal form of pyruvate carboxylase deficiency (cross-reacting material negative) presented with severe intractable lactic acidosis within 4 h after birth. He also had hyperammonemia, hypercitrullinemia, and hyperlysinemia. Plasma glutamine was not elevated. He had a rapidly deteriorating clinical course with severe liver dysfunction, repeated septicemia and seizures; he was comatose and was on a ventilator throughout; death occurred at 8 wk of age. Skin fibroblast study confirmed the enzyme deficiency. Detailed biochemical parameters and histopathology of the brain and liver are presented. The evidence from this infant suggests that disturbances of intracellular oxaloacetate levels as a result of the primary enzyme defect might also contribute to deficiency in ATP generation which may explain the various other biochemical changes and liver pathology.

Determination of the distribution of fatty acids and diethylstilbestrol between serum albumin and alpha-fetoprotein by concanavalin A affinity chromatography

The distribution of fatty acids and diethylstilbestrol between serum albumin and alpha-fetoprotein was measured in vitro by a new method based on the separation of the two proteins by virtue of the binding specificity of concanavalin A for the carbohydrate moiety of alpha-fetoprotein. Human and bovine proteins were investigated. It was found that palmitate and oleate were distributed almost equally between albumin and alpha-fetoprotein, while docosahexaenoate and diethylstilbestrol bound preferentially to alpha-fetoprotein even at an albumin: alpha-fetoprotein ratio of 10:1. The results confirm the binding specificity of alpha-fetoprotein for polyunsaturated fatty acids and also show that alpha-fetoprotein binds diethylstilbestrol much more strongly than albumin does. This suggests that alpha-fetoprotein may play a role in the fetal uptake of diethylstilbestrol.