Showing papers by "Montreal Children's Hospital published in 1992"

The role of oxidative stress in disease progression in individuals infected by the human immunodeficiency virus.

Abstract: This review describes the potential role of oxidative stress as a cofactor of disease progression from asymptomatic human immunodeficiency virus (HIV) infection to the acquired immunodeficiency syndrome (AIDS). Oxidative stress is a known activator of HIV replication in vitro through the activation of a factor that binds to a DNA-binding protein, NF-kappa B, which in turn stimulates HIV gene expression by acting on the promoter region of the viral long terminal repeat. Tumor necrosis factor alpha (TNF-alpha), an essential cytokine produced by activated macrophages, is also involved in the activation of HIV infection through similar mechanisms. TNF-mediated cytotoxicity of cells exposed to this substance is related to the generation of intracellular hydroxyl radicals. An indirect argument in favor of the role of oxidative stress in HIV-associated disease progression is the consumption of glutathione (GSH), a major intracellular antioxidant, during HIV infection and progression. GSH is known to play a major role in regulation of T cell immune functions. Oxidative stress may also play an important role in the genesis of cellular DNA damage and, in this context, may be related to HIV-associated malignancies and disease progression. Finally, the role of antioxidants as components of therapeutic strategies to combat HIV disease progression is discussed.

A population-based study of neuroblastoma incidence, survival, and mortality in North America.

Abstract: PURPOSEThe purpose of this study was twofold: (1) to provide a population-based estimate of neuroblastoma incidence, disease stage and age distribution, and survival and mortality rates in North America; and (2) to compare these figures in the province of Quebec at a time shortly before the institution of province-wide screening with those in a population-based control group, the Greater Delaware Valley (GDV) Pediatric Tumor Registry.MATERIALS AND METHODSIn Quebec, the four major pediatric teaching hospital records were searched for children with a diagnosis of neuroblastoma. Tumor board registry data and information supplied to the Division of Vital Statistics were also reviewed. Birth statistics were obtained from the population registry. The GDV Pediatric Tumor Registry is a population-based registry of pediatric cancer covering all of Delaware and parts of New Jersey, Pennsylvania, and Maryland. Age, stage of disease, and follow-up data were obtained through December 31, 1989, with Evans neuroblastoma...

The prevalence of pain in hospitalized patients and resolution over six months.

Abstract: Pain was assessed in 2415 randomly selected hospitalized patients. Fifty percent of the sample reported pain at the time of the interview, and 67% had experienced pain during the past 24 h. High levels of pain were more frequent in postpartum women, patients with diseases of the musculoskeletal systems and after injury or poisoning, but in all diagnostic categories there were patients whose lowest pain level in the preceding 24 h was moderate or severe. Patients who had undergone a surgical procedure during the past 7 days were more likely to report moderate or severe pain, but 21% of non-surgical patients reported moderate or severe pain. Twenty percent of those with pain reported that it had existed for more than 6 months. Patients reported significant impairment of function and distress as a consequence of pain. Use of analgesic medications was low overall and even lower for non-surgical patients. A decrease in pain over 3 weeks was predicted by pain of shorter duration, a shorter duration of hospitalization in the past year, and if a surgical procedure had been performed. None of these variables predicted pain resolution between 3 weeks and 3 or 6 months. Impairment of function did not increase with continuing pain but distress did. Medication use remained low at follow-up. The data indicate that current strategies to improve pain management need to be critically reviewed.

The behavioral response to formalin in preweanling rats

Abstract: The behavioural response of rat pups, 1–20 days of age, to subcutaneous injection of formalin in a rear paw is described. Formalin-injected pups were compared to handled controls and to pups that received an injection of normal saline. Ongoing behaviour was recorded every 2 min for 60 min after injection. Injection of normal saline produced little disorganization of behaviour, although day-1, -3 and -6 pups did frequently flex the limb on the injected side early in the session. Injection of 10 μl of 1% formalin depressed active and quiet sleep in pups 10 days old and younger. Much less disruption of sleep was observed in day-15 pups, and in day-20 pups it was necessary to increase the concentration of formalin to 2.5% to produce a consistent behavioural response. The specific responses of pups to formalin injection were flexion of the limb, shaking the limb, and licking the injected paw. Pups of all ages displayed all of these responses, but in pups younger than 10 days, only limb flexion was consistent. Shaking became a consistent response in day-10 pups and licking in day-15 and -20 pups. Non-specific behaviours (squirming, vigorous rear kicks with both hind limbs and convulsive whole body jerks) were markedly increased by formalin in younger pups with a developmental pattern: squirming and kicking in day-1 pups, kicking and jerking in day-3 to -15 pups. Non-specific behaviours decreased and specific behaviours increased with age. In addition, the overall intensity and duration of the response decreased with age. The biphasic time course of the response of adult rats to formalin injection did not appear until 15 days of age.

Enhanced detection of vesicoureteral reflux in infants and children with use of cyclic voiding cystourethrography.

Abstract: Cyclic voiding cystourethrography (VCUG) was prospectively evaluated to determine its ability to demonstrate vesicoureteral reflux (VUR) in children whose VCUG results were initially negative. The authors also assessed the effect of change in the patient's position on the detection of VUR. Seventy-seven children younger than 3 years of age, with negative results from a VCUG study performed while they were supine, underwent a second cycle of bladder filling after they were placed prone (group 1). Sixty-five children who were also younger than 3 years of age and had negative results from an initial VCUG examination performed in the usual supine position underwent a second cycle of bladder filling, which was also performed with the patient supine (group 2). VUR occurred in three children (4%) in group 1 and in eight (12%) in group 2. Most children (68.8%) in the two groups combined had grade II reflux. Cyclic VCUG increased detection of VUR, which led to a change in clinical treatment. Prone positioning did ...

Maple syrup urine disease: Interrelations between branched-chain amino-, oxo- and hydroxyacids; implications for treatment; associations with CNS dysmyelination

Abstract: Four patients with classical maple syrup urine disease were treated for up to 5885 days per patient with a relaxed protocol allowing branched-chain amino acid levels in plasma to rise about 5 times the normal mean value. The patients have had satisfactory development and lifestyle. They spent 318 days in hospital during 19,937 aggregate treatment days. Plasma levels of leucine and the corresponding 2-oxo acid were shown to be elevated disproportionately relative to the other branched-chain metabolites. Levels of isoleucine and valine were lower than those of leucine apparently because of runout into alternative metabolite pools, namely the R metabolites for isoleucine and the hydroxyacid for valine. The chronic accumulation of branched-chain 2-oxo acid(s) in our patients was associated with chronic dysmyelinating changes in CNS visible by imaging. Another patient with a thiamine-responsive variant of maple syrup urine disease had five acute crises incurring 29 days in hospital in a total of 6910 treatment days. However, she did not have chronic metabolic dyshomeostasis (her average plasma amino acid values were normal) and she had no evidence of dysmyelination. A relaxed treatment protocol for patients with maple syrup urine disease may benefit them in quality of life, but it apparently exacts a cost in metabolic control and CNS pathology.

Differential proliferative response of human and mouse astrocytes to gamma‐interferon

Abstract: We have previously shown that gamma-interferon promoted the proliferation of adult human astrocytes isolated from brain biopsy specimens. In contrast, in the present study, astrocytes derived from neonatal mouse brains and treated with recombinant murine gamma-interferon responded by a decreas (average of 50% at 100 U/ml) in proliferation. The basal rate of proliferation as assessed by bromodeoxyuridine incorporation was markedly increased in neonatal mouse astrocytes when compared to the adult human cells, suggesting that age, and the corresponding metabolic activity of cells, could be important determinants in the mitogenic response of astrocytes to cytokines. However, subsequent examinations of fetal human and adult mouse astrocytes, with comparable basal rate of proliferation to neonatal mouse and adult human cells respectively, showed gamma-interferon to promote DNA synthesis in fetal human astrocytes while inhibiting that of adult mouse astrocytes. The results suggest species differences in the proliferative response of human and mouse astrocytes to the cytokine gamma-interferon. © 1992 Wiley-Liss, Inc.

Racial hygiene, active euthanasia, and Julius Hallervorden.

Abstract: “Hallervorden-Spatz disease” represents a distinctive and readily recognizable eponym to neurologists and pediatricians; it denotes a rare, inherited, autosomal recessive disorder tha t is perhaps a neuraxonal dystrophy, characterized by the childhood onset of unrelenting progressive gait disturbance, spasticity, and dementia associated with prominent extrapyramidal signs such as dystonia, chorea, and athetosis.lZ2 Pathologic examination reveals iron deposition in the basal ganglia and widely disseminated axonal spheroids.3 The eponym recalls Julius Hallervorden and Hugo Spatz, the prominent German neuropathologists who jointly delineated both the clinical and pathologic features of this disorder in two sibl i n g ~ . ~ ~ ~ The definitive German6 and English7 language biographies of Julius Hallervorden focus on his prodigious scientific talents and either ignore or gloss over his activities during World War 11. His active involvement in the child and “T4” euthanasia program (detailed below) raises troubling questions regarding the moral obligations and limitations of medical science.

Cystic fibrosis mutations in French Canadians: three CFTR mutations are relatively frequent in a Quebec population with an elevated incidence of cystic fibrosis.

Abstract: The French-Canadian population in the Saguenay-Lac St. Jean region of northeastern Quebec has an elevated frequency of cystic fibrosis (CF). The average incidence of cystic fibrosis was 1 in 891 births and the prevalence of CF carriers was estimated to be 1 in 15. We tested for 10 mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene in 133 French-Canadian CF families from Quebec. Ninety-one families were from the Saguenay-Lac St. Jean region and 42 families were referred from other regions of Quebec. We detected the CFTR mutation in 93 and 92% of the CF chromosomes in the Saguenay-Lac St. Jean and the major-urban Quebec families, respectively. The two groups of French-Canadian families were significantly different for the proportions of CFTR mutations. The three most common mutations in the Saguenay-Lac St. Jean families were ΔF508 (58%), 621 + 1G T (23%), and A455E (8%); and in the major-urban Quebec families were ΔF508 (71%), 711 + 1G T (9%), and 621 + 1G T (5%). These results provide evidence for the role of founder effect in the elevated incidence of cystic fibrosis in the Saguenay-Lac St. Jean population.

Psychosocial Adjustment in Juvenile Arthritis

Abstract: Psychosocial adjustment in 102 children with arthritis, ages 4-16, and their families was assessed by parents, who completed the Child Behavior Checklist (CBCL) and Profile of Mood States (POMS). On average, parental distress (POMS) was lower than reference norms. POMS distress was correlated with children's behavioral problems (r = .41) but not with children's social competence (r = .15). General linear models explained 25% of the variance in CBCL behavioral problem scores. Older age was associated with more behavior problems in males, but not females. Disease severity and disease activity were also associated with behavioral problems. Although 27% of the variance in CBCL social competence could be explained, no single predictor variable was especially strong. Poorer social competence was associated with older age and shorter disease duration. Teenagers, especially those with recent onset and those with mild disease activity, may be at increased risk for psychosocial maladjustment.

DNA methyltransferase is developmentally expressed in replicating and non-replicating male germ cells

Abstract: Genomic methylation patterns are established during maturation of primordial germ cells and during gametogenesis. While methylation is linked to DNA replication in somatic cells, active de novo methylation and demethylation occur in post-replicative spermatocytes during meiotic prophase (1). We have examined differentiating male germ cells for alternative forms of DNA (cytosine-5)-methyltransferase (DNA MTase) and have found a 6.2 kb DNA MTase mRNA that is present in appreciable quantities only in testis; in post-replicative pachytene spermatocytes it is the predominant form of DNA MTase mRNA. The 5.2 kb DNA MTase mRNA, characteristic of all somatic cells, was detected in isolated type A and B spermatogonia and haploid round spermatids. Immunobolt analysis detected a protein in spermatogenic cells with a relative mass of 180,000-200,000, which is close to the known size of the somatic form of mammalian DNA MTase. The demonstration of the differential developmental expression of DNA MTase in male germ cells argues for a role for testicular DNA methylation events, not only during replication in premeiotic cells, but also during meiotic prophase and postmeiotic development.

Intrafamilial variability in cleidocranial dysplasia: a three generation family.

Abstract: We present a 3-generation family, ascertained after the birth of a child with cleidocranial dysplasia (CCD). The propositus presented with respiratory distress (due to a narrow thorax) and hypoplasia and discontinuity of both clavicles. The mother, aunt, and grandmother had varied features of the condition. This intrafamilial variation illustrates the need for clinical assessment of family members following the birth of an apparent sporadic case of CCD.

A new Tay-Sachs disease B1 allele in exon 7 in two compound heterozygotes each with a second novel mutation.

Abstract: Three novel Tay--Sachs Disease (TSD) mutations have been identified in two unrelated, non-Jewish compound heterozygous patients. A G772C transversion mutation causing an Asp258His substitution is shared by both patients. The mutant enzyme had been characterized, on the basis of previous kinetic studies (1) as a B1, or alpha-subunit active site mutation. This is the first B1 mutation not found in codon 178 (exon 5). A C508T transition causing an Arg170Trp substitution also occurred in one of the patients. The third mutation is a two base deletion occurring in exon 8 involving the loss of either nts 927-928 or 929-930 in codon 310. The deletion creates an inframe termination codon 35 bases downstream. The Arg170Trp mutation was also detected in a third unrelated TSD patient. In both families this allele was traced to French Canadian ancestors originating in the Estrie region of the province of Quebec. This mutation is the third TSD allele unique to the French Canadian population and the ancestral origins of the carrier parents are distant from the center of diffusion of the more common 7.6 kb deletion mutation which is in the eastern part of the province.

Factors Predicting Course of β-cell Function in IDDM

Abstract: OBJECTIVE The purpose of this study was to determine whether the severity o clinical presentation, sex, age, HLA type, and the presence of IAs and ICAs could predict the variation of residual insulin secretion as measured by the serum C-peptide response to a Sustacal meal. RESEARCH DESIGN AND METHODS A cohort of 151 newly diagnosed IDDM children (mean age 10.2 ± 4.6 yr) was followed prospectively for 3 yr. Thirty-five patients (12 males, 23 females) were still secreting C-peptide after 36 mo. RESULTS We found that age ( P = 0.0001), sex ( P = 0.003), presence of ICA ( P = 0.006), severity of clinical presentation ( P = 0.001), and symptom duration ( P = 0.002) significantly predicted the rate of loss of C-peptide secretion. The risks of accelerated C-peptide disappearance decreased with increasing age, the risk ratios being 0.25 for the older group (> 12 yr) compared with the younger group (< 6 yr) and 0.50 for the intermediate group (6–12 yr) compared with the younger group. The risk for the presence of ICA was 1.7, and the risk for males was 1.7 also. There was a significant negative correlation between ICA titers and C-peptide at 18 and 24 mo after diagnosis ( P = 0.04). There were no significant differences in HbA1 values between patients who secreted C-peptide and those who did not. CONCLUSIONS We conclude that younger age of onset, male sex, high titers of ICA, severe clinical presentation, and shorter symptom duration significantly predict accelerated rates of loss of C-peptide secretion.

The French Canadian Tay-Sachs disease deletion mutation: identification of probable founders.

Abstract: Tay-Sachs disease (TSD) is an inherited neurodegenerative ganglioside storage disorder caused by deficiency of the hexosaminidase A enzyme. A deletion allele (FCD) at the HEXA locus has attained high frequency in the French Canadian population. The distribution of affected probands shows a likely center of diffusion for this mutation located in the Bas-St.-Laurent and Gaspesie regions of the province of Quebec. We have reconstructed the genealogies of 15 obligate carriers of the FCD allele to an average depth of 12 generations identifying 60 ancestors and 80 European founders common to all of them. The ancestral origins of the European founders show a significantly greater number of individuals born in the French provinces of Normandy and Perche than expected based on information regarding the origins of the 8,500 immigrants who settled the colony of New France during the French regime. We have identified common ancestors among the 10 who were born in Quebec who appear to be likely candidates for the origin of the FCD mutation. One such couple had 11 children, 5 of whom settled in regions of Quebec or New Brunswick that today have elevated heterozygote frequencies for the FCD. The five offspring are ancestors of all known carriers. By contrast, the absence of FCD alleles among TSD probands in France suggests that the mutation did not occur in a European founder.

Differences in Ca(2+)-mediation of hypotonic and Na(+)-nutrient regulatory volume decrease in suspensions of jejunal enterocytes.

Abstract: We determined differences in the Ca2+ signalling of K* and Cl− conductances required for Regulatory Volume Decrease (RVD) in jejunal villus enterocytes passively swollen (0.5 or 0.95, isotonic) compared with swelling because of the absorption of d-glucose (d-Glc) or l-Alanine (l-Ala). Cell volume was measured using electronic cell sizing. In nominally Ca2+-free medium containing EGTA (100 μm) RVD after 0.5 or 0.95, isotonic challenge was prevented. l-Ala swelling and subsequent RVD was influenced in Ca2+-free medium. Villus cells were incubated with 10 μm of the acetomethoxy derivative of 1,2.bis (2-aminophenoxy) ethane N,N,N1,N1 tetracetic acid (BAPTA-AM) and RVD after 0.5 · isotonic swelling or l-Ala swelling was prevented. Niguldipine (0.1 μm), nifedipine (5 μm), diltiazem (100 μm), Ni2+, and Co2+ (1 mm) all prevented hypotonic RVD but had no effect on RVD after l-Ala addition. Charybdotoxin (25 nm) a potent inhibitor of Ca2+-activated K+ channels, had no effect on hypotonic RVD but prevented RVD of villus cells swollen by d-Glc. We used the calmodulin antagonists, napthalene sulfonamide derivatives W-7 and W-13, to assess calmodulin activation of K+ and Cl− conductance in these two models. l-Ala swelling and subsequent RVD was not influenced by 25 μm W-7; hypotonic RVD was prevented by 25 μm W-7 or 100 μmW-13. The W-13 inhibition of RVD was by-passed with 0.5 μm gramicidin. Our data show that hypotonic RVD requires extracellular Ca2+ and that the K+ conductance activated is not charybdotoxin sensitive but requires calmodulin. Na+-nutrient RVD requires intracellular calcium mobilization to activate a charybdotoxin-sensitive K+ conductance. The signalling for RVD after cell swelling because of transport of osmotically active Na+ nutrient is different than the signalling for RVD after passive hypotonic cell swelling.

A mutation common in non‐jewish Tay–Sachs disease: Frequency and RNA studies

Abstract: Tay-Sachs disease (TSD) is an autosomal recessive genetic disorder resulting from mutation of the HEXA gene encoding the α-subunit of the lysosomal enzyme, β-N-acetylhexosaminidase A (Hex A). We have discovered that a Tay-Sachs mutation, IVS-9 + 1 GA, first detected by Akli et al. (Genomics 11:124–134, 1991), is a common disease allele in non-Jewish Caucasians (10/58 alleles examined). A PCR-based diagnostic test, which detects an NlaIII site generated by the mutation, revealed a frequency among enzyme-defined carriers of 9/64 (14%). Most of those carrying the allele trace their origins to the United Kingdom, Ireland, or Western Europe. It was not identified among 12 Black American TSD alleles or in any of 18 Ashkenazi Jewish, enzyme-defined carriers who did not carry any of the mutations common to this population. No normally spliced RNA was detected in PCR products generated from reverse transcription of RNA carrying the IVS-9 mutation. Instead, the low levels of mRNA from this allele were comprised of aberrant species resulting from the use of either of two cryptic donor sites, one truncating exon 9 and the other within IVS-9, spliced to exon 10. Numerous additional splice products were detected, most involving skipping of one or more surrounding exons. Together with a recently identified allele responsible for Hex A pseudodeficiency (Triggs-Raine et al. Am J Hum Genet, 1992), these two alleles accounted for almost 50% (29/64) of TSD or carrier alleles ascertained by enzyme screening tests in non-Jewish Caucasians. © 1992 Wiley-Liss, Inc.

3-Methylglutaconic aciduria: a marker for as yet unspecified disorders and the relevance of prenatal diagnosis in a 'new' type ('type 4').

Abstract: The Mendelian disorder known as 3-methylgutaconic aciduria (McKusick 250950) gives evidence of allelic and locus heterogeneity. Type 1 has a mild clinical phenotype and confirmed 3-methylgutaconyl-CoA hydratase deficiency; inheritance is autosomal recessive. Other forms have major clinical manifestations and subdivide into X-linked (type 2), a form in Iraqi Jews with optic atrophy (so-called type 3); and untyped (putative autosomal recessive) forms without identified enzyme defects. In the latter, 3-methylglutaconic aciduria may simply be a marker for another metabolic disorder.

Acrania: a manifestation of the Adams-Oliver syndrome.

Abstract: A 10-year-old male with acrania, distal limb anomalies, and abnormal arterial and venous cranial blood vessels is reported. Parental films and examination are normal. This case supports the hypothesis that acrania is a severe form of aplasia cutis congenita and is within the spectrum of Adams-Oliver syndrome. It is proposed that the diagnosis of acrania requires assessment of both parents and proband to assess other manifestations of vascular disruption in order to provide accurate genetic counselling. © 1992 Wiley-Liss, Inc.

The intron 7 donor splice site transition: a second Tay-Sachs disease mutation in French Canada.

Abstract: Mutations at the hexosaminidase A (HEXA) gene which cause Tay-Sachs disease (TSD) have elevated frequency in the Ashkenazi Jewish and French-Canadian populations. We report a novel TSD allele in the French-Canadian population associated with the infantile form of the disease. The mutation, a G-->A transition at the +1 position of intron 7, abolishes the donor splice site. Cultured human fibroblasts from a compound heterozygote for this transition (and for a deletion mutation) produce no detectable HEXA mRNA. The intron 7 + 1 mutation occurs in the base adjacent to the site of the adult-onset TSD mutation (G805A). In both mutations a restriction site for the endonuclease EcoRII is abolished. Unambiguous diagnosis, therefore, requires allele-specific oligonucleotide hybridization to distinguish between these two mutant alleles. The intron 7 + 1 mutation has been detected in three unrelated families. Obligate heterozygotes for the intron 7 + 1 mutation were born in the Saguenay-Lac-St-Jean region of Quebec. The most recent ancestors common to obligate carriers of this mutation were from the Charlevoix region of the province of Quebec. This mutation thus has a different geographic centre of diffusion and is probably less common than the exon 1 deletion TSD mutation in French Canadians. Neither mutation has been detected in France, the ancestral homeland of French Canada.

Branchio-oto-renal syndrome : further delineation of an underdiagnosed syndrome

Abstract: We report on a woman who was diagnosed with branchio-oto-renal (BOR) syndrome after 2 pregnancies complicated by oligohydramnios due to renal hypoplasia and agenesis. Both babies died neonatally of pulmonary hypoplasia. Histopathology of the temporal bones of the second child showed marked immaturity of the middle ear cleft, ossicles, facial nerve and canal, and cochlear nerve. Maternal renal ultrasound study was normal although intravenous pyelography indicated renal hypoplasia. The frequency of BOR syndrome among cases of recurrent fetal renal hypoplasia/dysplasia or agenesis is unknown, and parental renal ultrasonography may not identify a heritable renal defect. Investigations should include a family history, and examination of relatives to look for preauricular pits, lacrimal duct stenosis, and branchial fistulae and/or cysts. Hearing studies and IVP may be indicated. © 1992 Wiley-Liss, Inc.

Specificity and sensitivity of hexosaminidase assays and DNA analysis for the detection of Tay-Sachs disease gene carriers among Ashkenazic Jews.

Abstract: Tay-Sachs disease (TSD), a neurodegenerative disorder resulting from a deficiency of the lysosomal enzyme hexosaminidase A (HexA), clusters in Ashkenazic Jews. Population-based screening programs to detect carriers of TSD genes by means of HexA assays have been active since the 1970s. The recent characterization of 3 mutations in the HEXA gene (in exon 7, exon 11, and intron 12), which account for over 90% of HEXA mutations in Ashkenazim, appeared to offer better options for screening and diagnosis. The relative frequencies of the three mutations in Montreal are similar to those reported in four other North American populations. We compared enzyme and DNA analyses to determine specificity and sensitivity of each test when the other was used as the confirmatory procedure. Neither procedure has a sensitivity of 1.0. Maximum sensitivity and specificity were achieved by using both tests together. The findings here are likely to apply to most cases where the variant screened enzyme phenotype can result from more than one mutation.

In vitro and in vivo correlations for I65T and M1V mutations at the phenylalanine hydroxylase locus.

Abstract: Mutations at the phenylalanine hydroxylase (PAH) locus are the major cause of hyperphenylalaninemia. We have previously described four mutations (M1V, IVS12nt1, R408W, and S349P) at the PAH locus in French Canadians with ancestry in eastern Quebec. Here we report (1) identification of another mutation, on a haplotype 9 chromosome, which converts codon 65 from isoleucine (ATT) to threonine (ACT), (2) expression analysis of the I65T mutation in COS cells demonstrating 75% loss of both immunoreactive protein and enzyme activity, and (3) expression analysis of the most prevalent PKU allele (M1V) in eastern Quebec, showing nondetectable levels of PAH protein and activity, a finding compatible with a mutation in the translation initiation codon. Homozygosity for M1V and codominant inheritance of I65T/R408W were both associated with classical phenylketonuria.

Ultrasound screening of high-risk infants. A method to increase early detection of congenital dysplasia of the hip.

Abstract: • Congenital dysplasia of the hip (CDH) continues to be missed by routine physical screening examinations in the early months when treatment is most effective. Real-time ultrasonography (US) is valuable in the detection of CDH in the young infant. We performed a prospective study to evaluate one US screening strategy that targets a select "high-risk newborn" population at risk for CDH aiming to increase the early diagnosis of this condition. From 1772 consecutive births at one hospital, we identified 97 (5.5%) newborns with risk factors for CDH: breech delivery, 73 babies; family history, 26 babies; postural abnormalities, five babies; and oligohydramnios, four babies. Eleven newborns had two risk factors. We studied 69 of these newborns with US. There were four cases of CDH in this group. Three of these babies had completely normal pediatric physical examination results at the time of the US study (at 14, 75, and 100 days, respectively) despite dysplasia diagnosed by US. All were successfully treated with a harness as outpatients. We conclude that a screening program entailing identification and subsequent US of the hip of newborns with specific physical and historical risk factors for CDH increases early diagnosis. Further analysis suggests this approach is cost-effective. (AJDC. 1992;146:230-234)

Effect of protein kinase C inhibitors on Cl- conductance required for volume regulation after L-alanine cotransport.

Abstract: We used electronic cell sizing and Cl- efflux measurements in guinea pig jejunal enterocytes to study activation of Cl- conductance under two experimental conditions, regulatory volume decrease (RVD) after passive hypotonic swelling and volume regulation during Na(+)-alanine cotransport. RVD after a hypotonic (0.5 x isotonic) challenge was not affected by the protein kinase C (PKC) inhibitor 100 microM 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7). Volume decrease after cell swelling in response to L-Ala (25 mM) was prevented by H-7 (P less than 0.05) or the more potent PKC inhibitor 10 nM staurosporine (P less than 0.001). L-Ala stimulated biphasic 36Cl efflux, a rapid efflux over 60 s which was inhibited by H-7 (P less than 0.01) and the Cl(-)-channel blocker anthracene-9-carboxylic acid (9-AC) (P less than 0.005). In contrast, after hypotonic dilution the rate of 36Cl efflux increased (P less than 0.005); H-7 had no effect but 9-AC inhibited the increase (P less than 0.01). Gramicidin (0.5 microM) added to cells maximally swollen by L-Ala in Cl(-)-containing medium caused 2 degree swelling (P less than 0.001), but 10 nM staurosporine reduced this 2 degree swelling (P less than 0.001). Addition of phorbol ester or synthetic diacylglycerol to villus cells under isotonic conditions, after gramicidin addition, caused cell swelling (P less than 0.005) that was inhibited by staurosporine (P less than 0.05). We concluded that PKC does not activate Cl- conductance for hypotonic RVD but that Na(+)-nutrient cotransport is a physiological stimulus for PKC to activate Cl- conductance necessary for volume regulation.