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Biomedical subjects

C Bay

Publications and source records attributed to C Bay.

At least 19 recordsLinked to original sources
PubMed2003

Normal cognition and behavior in a Smith-Lemli-Opitz syndrome patient who presented with Hirschsprung disease.

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive disorder of cholesterol biosynthesis. It is caused by mutations in the gene encoding the enzyme 7-dehydrocholesterol Delta7-reductase (DHCR7), which catalyzes the final step in cholesterol biosynthesis, usually resulting in cholesterol deficiency. We report a 3.5-year-old girl who has cognition in the low average range and normal behavior, but in whom molecular studies identified two missense mutations in DHCR7: V326L and F284L. She was born at term following an uncomplicated pregnancy and delivery, and presented at 12 days of age with poor feeding, abdominal distention, and jaundice. Colonic biopsy was consistent with Hirschsprung disease. On physical examination she had mild ptosis, a long philtrum, mild micrognathia, a short, upturned nose, and subtle 2,3 syndactyly. Her 7-dehydrocholesterol (7-DHC) level was markedly elevated at 8.7 mg/dl (normal 0.10 +/- 0.05), and her cholesterol level was normal at 61 mg/dl (normal for newborn period 50-80 mg/dl). Karyotype analysis was normal, 46,XX. Breast milk feeding was initiated and continued for 18 months. Cholesterol supplementation was implemented at 100 mg/kg/day at 3 months, which resulted in increased cholesterol levels and reduced dehydrocholesterol levels. Neuropsychological testing has shown functioning in the low average range, between the 14th and 18th centiles when compared to peers. This is markedly higher than most children with SLOS. She has no behavioral problems. MRI and MRS testing of the brain revealed no structural abnormalities. This is in contrast to a recently reported case by Prasad et al. [2002: Am J Med Genet 108:64-68] with a mild phenotype, behavioral problems, and abnormal MRI, who is compound heterozygote for both a null and missense mutation. Our case suggests that patients with severe feeding disorders with or without Hirschprung disease and postnatal onset microcephaly may warrant screening for SLOS.

Behavior↗
PubMed2003

MRI and 1H MRS findings in Smith-Lemli-Opitz syndrome.

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive disorder characterized by a defect in cholesterol biosynthesis, associated with mental retardation and multisystem structural abnormalities. This study investigated the prevalence of congenital CNS abnormalities by MRI in a large series of patients with SLOS and the correlation of the clinical and biochemical findings with the results of MRI and 1H MRS. Eighteen patients were studied; all underwent MRI of the brain, and 16 had 1H MRS of the cerebral white matter. The ratios choline:NAA, lipid:NAA, and lipid:choline metabolite were found to be correlated with the clinical degree of disease severity, serum total sterol ratios (cholesterol/cholesterol + 7-dehydrocholesterol + 8-dehydrocholesterol) and in two cases with the effect of cholesterol therapy. Abnormal CNS findings were noted in five patients, including callosal abnormalities (n = 4), Dandy-Walker variant (n = 1), and arachnoid cyst (n = 1). Holoprosencephaly was noted in one patient with a prevalence of 6%. Choline:NAA was elevated in seven patients. There was a statistically significant positive correlation between the lipid:choline ratio and the serum cholesterol precursor, 8-dehydrocholesterol. In two patients 1H MRS demonstrated abnormally elevated lipids prior to cholesterol therapy, which improved on therapy. The use of MRI and 1H MRS is an effective way to demonstrate brain structural abnormalities in patients with SLOS and may prove to be an effective method for the assessment of the effects of cholesterol replacement therapy in the brain.

Adolescent↗
PubMed2003

Motor vehicle crash fatalities by race/ethnicity in Arizona, 1990-96.

OBJECTIVE: To compare rates of motor vehicle crash (MVC) fatalities among different race/ethnic groups in urban and rural Arizona. METHOD: Using the Fatality Analysis Reporting System and the National Center for Health Statistics Multiple Cause of Death file, MVC fatalities in Arizona from 1990-96 inclusive were classified by gender, race/ethnicity, and urban or rural residence. Age adjusted rates of total, occupant, pedestrian, and alcohol related fatalities were calculated. The total MVC fatality rate for each race/ethnic group was then adjusted for proportion of rural residence. RESULTS: Compared with non-Hispanic whites (NHWs), American Indians had raised relative risks for MVC fatality in all gender and residence subgroups. Hispanic females and rural Hispanic males had lower relative risks, as did rural African-American men. Raised relative risks for American Indian men and women included all subgroups: total, occupant, pedestrian, and alcohol related. Hispanic and African-American men both had raised relative risks of pedestrian related fatalities, and Hispanic men had a slightly higher relative risk while Hispanic women had a lower relative risks, for alcohol related fatality. Hispanic men and women and African-American men had lower occupant fatality rates. Close to half (45%) of the excess MVC fatality among American Indians can be attributed to residence in rural areas, where MVC fatality rates are higher. There were 1.85 occupants in crashes involving NHW deaths compared with 2.51 for Hispanics and 2.71 for American Indians (p<0.001). The proportion of occupants not using a seatbelt was higher in Hispanics and American Indians in both urban and rural areas. CONCLUSION: The major disparity in MVC fatality in Arizona is among American Indians. The higher MVC fatality rates among American Indians occur in all age groups, in both urban and rural areas, and among occupants and pedestrians. Rural residence, lower rates of seatbelt use, higher rates of alcohol related crashes, a greater number of occupants, and higher rates of pedestrian deaths all contribute to the American Indian MVC fatality disparity. High rates of pedestrian fatality occur in men in all three race/ethnic minorities in Arizona and among American Indian women. In contrast to other studies, African-Americans and Hispanics did not have raised total MVC fatality rates and compared to NHWs actually had lower rates in the rural areas of the state.

Accidents, Traffic↗
PubMed1999

Neurologic nonmetabolic presentation of propionic acidemia.

BACKGROUND: Patients with propionic acidemia usually present in the neonatal period with life-threatening ketoacidosis, often complicated by hyperammonemia. It was thought that the neurologic abnormalities seen in this disease were exclusively the consequences of these acute crises. Experience with 2 patients with propionic acidemia indicates that this disease may present first with prominent neurologic disease without the life-threatening episodes of ketoacidosis that usually serve as the alerting signals for a diagnosis of an organic acidemia. OBJECTIVE: To examine the clinical and metabolic aspects of 2 patients with a phenotype that suggested disease of the basal ganglia. DESIGN: Examination of patterns of organic acids of the urine and enzyme assay for propionyl-CoA carboxylase in fibroblasts and lymphocytes. SETTING: Referral population to a biochemical genetics laboratory. PATIENTS: Two patients whose prominent features were hypotonia followed by spastic quadriparesis and choreoathetosis. Both had seizures. One patient was mildly mentally retarded but grew normally physically. The other had profound mental retardation and failure to thrive; he also self-mutilated his lower lip. Self-injurious behavior has not been reported in this disease. MAIN OUTCOME MEASURES: Clinical description, blood ammonia levels, organic acid levels in the urine, and enzyme activity. RESULTS: Excretion of metabolites, including methylcitrate, was typical. Residual activity of propionyl-CoA carboxylase approximated 5% of the control in each patient. CONCLUSIONS: Propionic acidemia can present as a pure neurologic disease without acute episodes of massive ketoacidosis. Hyperammonemia may occur after infancy in some patients, presenting as Reye syndrome.

Adult↗
PubMed1998

Carbon dioxide dynamics during apneic oxygenation: the effects of preceding hypocapnia.

STUDY OBJECTIVE: To compare the rate of increase of arterial carbon dioxide tension (PaCO2) during apneic oxygenation preceded by acute respiratory hypocapnia with that during apnea preceded by respiratory eucapnia. DESIGN: Randomized, prospective, single crossover study. SETTING: Operating room at a teaching hospital. PATIENTS: 19 ASA physical status I, II, and III patients requiring general endotracheal anesthesia and invasive monitoring for elective surgery. INTERVENTIONS: Two ventilatory states preceding apneic oxygenation were studied in each patient. The first respiratory state was established using controlled mechanical ventilation in the stable, anesthetized patient, followed by a 5-minute period of apneic oxygenation. Arterial and mixed central venous blood gas samples were obtained simultaneously prior to and at 1-minute intervals during apnea. Ventilatory parameters were then changed to establish the second respiratory state. During the subsequent period of apnea, the study was repeated as above. MEASUREMENTS AND MAIN RESULTS: Arterial and mixed central venous partial pressure of carbon dioxide (pCO2) levels were measured. A greater increase in PaCO2 was found during the first minute of apneic oxygenation in the hypocapneic group compared with the eucapneic group. The venoarterial gradient of pCO2 was also greater in the hypocapneic group prior to apnea. CONCLUSIONS: Acute hypocapnia compared with eucapnia prior to apneic oxygenation is associated with a greater rise in PaCO2 in the anesthetized patient. This finding may be due in part to widening of the venoarterial gradient of pCO2.

Adult↗
PubMed1998

The use of albuterol in hospitalized infants with bronchiolitis.

OBJECTIVES: To determine whether the use of albuterol by nebulization enhances physiologic or clinical recovery in hospitalized infants with moderate bronchiolitis. METHODS: This prospective, double-blind, placebo-controlled, randomized clinical trial was performed from December 1995 to March 1996. A total of 52 patients <24 months of age with a diagnosis of moderately severe, acute viral bronchiolitis were enrolled and assigned to receive nebulized albuterol or normal saline placebo for 72 hours under a standardized protocol. Primary outcome measures included improvement in oxygen saturation (SaO2) during hospitalization and survival analysis to assess the time required to reach preestablished discharge criteria on three measures: SaO2, accessory muscle use, and wheezing. An additional secondary outcome measure was actual length of hospital stay. Adverse outcomes also were compared between treatment groups. RESULTS: There was no significant difference in mean SaO2 between albuterol and placebo at baseline, 24 hours, or maximum SaO2 achieved during hospitalization. Both groups showed significant improvement in oxygen saturation over time, but there was no significant difference in improvement between the two groups. The study had a power of 90% to detect a difference in mean percentage point improvement of 2% SaO2. There was no difference in time to reach discharge criteria as defined by SaO2, accessory muscle use, or wheezing. There was no difference in length of hospital stay or in the frequency of adverse outcomes. CONCLUSIONS: Nebulized albuterol therapy does not appear to enhance recovery or attenuate severity of illness in infants hospitalized with acute, moderate bronchiolitis, as evidenced by improvement in oxygen saturation, time to meet standardized discharge criteria, or length of hospital stay.

Adrenergic beta-Agonists↗
PubMed1997

Analgesia for emergency centers' orthopaedic patients: does an ethnic bias exist?

Several prior studies have demonstrated that Hispanics treated in some emergency centers were prescribed less analgesia than white patients with similar extremity trauma. The purpose of this study was to determine if other institutions had a similar experience with regard to undermedication of certain ethnic groups. Two cohorts were studied, 1 adult and 1 pediatric group. The adult group consisted of 84 patients seen at Maricopa Medical Center, Phoenix, Arizona, between January 1, 1992, and December 31, 1992, who were treated for isolated long bone fractures requiring a closed reduction. The pediatric group consisted of 63 children younger than 16 years, seen between January 1, 1992, and April 30, 1993, with isolated distal radius or ulna fractures requiring a closed reduction. Results indicated that Hispanics were not likely to be undermedicated for fracture reduction in this level I trauma emergency center compared with whites. It is thought that a hospital with a larger populations of underrepresented minorities may be more sensitive than other private institutions.

Adult↗
PubMed1997

The rat subcutaneous air sac model: a new and simple method for in vivo screening of antiangiogenesis.

An experimental rat model, the Subcutaneous Air Sac (SAS) model, was developed to provide an animal model in which neo-vascularization can be easily assessed in situ and quantified using a radiolabelled plasma marker. The SAS model was designed to replace a previous model where neovascularization was induced by chemical injury of rat or rabbit cornea or by implantation of tumour cells intracorneally, a methodology which is believed to cause severe pain to the animals. In the SAS model the air sac replaces the cornea as a transparent avascular substratum in which vascularization can be observed. The air sac is induced by injection of air subcutaneously on the back of the animal. After 8 to 10 days a sufficient air sac has been established. The animal is anaesthesized and by a minor operation the cellulose sponge is implanted upon the air sac under the skin. The vasoproliferative effect of the cellulose sponge causes formation of new vessels which are macroscopically visible 10 days after implantation. The ability of the in vivo SAS model to show an antiangiogenic effect of a systemically applied test compound was investigated using the fumagillin analogue TNP-470 (ochloro-acetylcarbamoyl)-fumagillol) as a positive control at dose levels of 0, 1, 2.5, 5 and 10 mg/kg/day given subcutaneously for 10 days. The neo-angiogenesis was scored both in situ using a subjective point system and by measuring the 125I-activity of the implant and the membrane after an intravenous injection of 125I-labelled antibodies. The neo-angiogenesis was reduced by approximately 45-50% in animals treated with 5 or 10 mg/kg/day of TNP-470 compared to animals treated with the vehicle. The animals treated with 10 mg/kg/day TNP-470 showed signs of toxicity. The SAS model is considered highly relevant for in vivo testing of potential antiangiogenic drugs on humane grounds. The high reproducibility, the low cost and the technical simplicity of the method makes it attractive.

Air↗
PubMed1995

Is academic managed care an oxymoron?

BACKGROUND: A review of 1993 data on length of stay (LOS) and charges for diagnosis-related group (DRG) 195 (complicated cholecystectomies) showed that Maricopa Medical Center charged more and had longer LOS than all other area hospitals. METHODS: Twenty DRG 195 charts were analyzed for the causes of the inefficiencies. The remaining cholecystectomy DRGs were similarly analyzed. RESULTS: Analysis of the charts for DRG 195 showed that 55% of the patients had laparoscopic conversions. Charges and LOS varied significantly because of the conversions, increased preoperative hospital days and increased operative times. Moreover, 30% of patients were more than 70 years old. Comparisons of other cholecystectomy DRGs showed similar inefficiencies, indicating a hospital system's problem. CONCLUSIONS: Diagnosis-related group delta analysis is a powerful performance improvement tool. Once problem areas are identified and corrected, monitoring prospective data produces rapid analysis of quality of care and cost improvements. The models can serve as a means for teaching hospitals to become more competitive and satisfy the Joint Commission on Accreditation of Healthcare Organizations requirements for patient-care improvements.

Adult↗
PubMed1994

Linkage of a human brain malformation, familial holoprosencephaly, to chromosome 7 and evidence for genetic heterogeneity.

Holoprosencephaly (HPE) is a common malformation of the developing forebrain and midface characterized by incomplete penetrance and variable expressivity. Familial HPE has been reported in many families with autosomal dominant inheritance in some and apparent autosomal recessive inheritance in others. We have examined 125 individuals from nine families with autosomal dominant HPE. Expression in gene carriers varied from alobar HPE and cyclopia through microforms such as microcephaly or single central incisor to normal phenotype. We performed linkage studies by either Southern blot or polymerase chain reaction analyses with DNA markers (D7S22, D7S550, and D7S483) that are deleted from some patients with sporadic HPE and flank a translocation breakpoint in 7q36 associated with HPE. The strongest support for linkage was with D7S22, which was linked with no recombination to autosomal dominant HPE in eight of nine families with a combined logarithm of odds score of 6.4 with an affected-only model-free analysis and 8.2 with a reduced-penetrance model and all phenotypes. Close linkage to this region could be excluded in one family, and there was significant evidence of genetic heterogeneity. These results show that a gene for autosomal dominant HPE is located in a chromosomal region (7q36) known to be involved in sporadic HPE with visible cytogenetic deletions. They also demonstrate genetic heterogeneity in familial HPE. We hypothesize that mutations of a gene in 7q36, designated HPE3, are responsible for both sporadic HPE and a majority of families with autosomal dominant HPE.

Adolescent↗
PubMed1993

Mild Brachmann-de Lange syndrome. Delineation of the clinical phenotype, and characteristic behaviors in a six-year-old boy.

Brachmann-de Lange syndrome (BDLS) is a rare multiple congenital anomaly/mental retardation (MCA/MR) syndrome with variable expression, making diagnosis of mild cases difficult. The most consistent manifestations appear to be the characteristic face, which can be subtle in children who are mildly affected [Ireland and Burn, 1991: Twelfth Annual David W. Smith Workshop on Malformations and Morphogenesis]. Other aspects of the syndrome include variable degrees of mental retardation, growth retardation, structural abnormalities of the limbs, and behavior abnormalities, noted to be "autistic" [Jones, 1988: "Smith's recognizable patterns of human malformation"]. Johnson et al. [1976: Pediatr Res 10:843-850] described a behavior phenotype felt to be common in patients with BDLS. They predicted that patients with BDLS may respond to "behavioral intervention". Other behavior abnormalities in BDLS have been reported [Barr et al., 1971: Neuropadiatrie 3:46-66; Hawley et al., 1985: Am J Med Genet 20:453-459]. We report on a 6-year-old boy with the facial characteristics of BDLS, normal birth weight, prenatal onset of a small head relative to length, postnatal onset growth deficiency, nearly normal psychomotor development with onset of clear developmental delays by 2 years. He developed behavior problems similar to those seen in other patients with BDLS. These behaviors are most consistent with Pervasive Development Disorder-NOS (PDD), and Autistic Disorder [DSM-III-R, 1987] which encompasses a spectrum of mild to severe autistic behaviors. We report successful in-patient care utilizing medical and behavioral techniques to reduce the frequency of the behaviors. We feel that the presence of the characteristic behaviors may be helpful in confirming the diagnosis of BDLS.

Autistic Disorder↗
PubMed1985

An evaluation of protein requirements in methylmalonic acidaemia.

A 3-month-old girl and a 13-month-old boy with vitamin B12-unresponsive methylmalonic acidaemia were studied to determine responses to varying levels of protein intake of growth, nitrogen balance and organic acid metabolism. A linear increase in the excretion of methylmalonic acid was observed in both patients above a critical level of protein intake. The inflection point was judged to reflect a ceiling above which amino acid intake exceeded requirements and catabolism was initiated. Below this point in each infant there was a plateau of minimal excretion of methylmalonic acid. Within this plateau level a reasonable rate of growth and metabolic stability were achieved at intakes between 0.70 and 0.75 and between 0.75 and 1.17 g protein kg-1, respectively, indicating that there is a range of protein tolerance and the importance of an individual approach to the provision of protein in patients with methylmalonic acidaemia. In the 3-month-old infant, nitrogen equilibrium was achieved at protein intakes above 0.6 g kg-1 and modest nitrogen retention was attained at a protein intake of 0.75 g kg-1, a level at which the excretion of methylmalonic acid was minimal and weight gain satisfactory. A protein intake of 1.25 g kg-1 was required to achieve a level of nitrogen retention often considered optimal for normal growth; however, this infant demonstrated an elevated excretion of methylmalonic acid and was close to clinical illness at this level of protein intake. The 13-month-old infant demonstrated a normal level of nitrogen retention, minimal excretion of methylmalonic acid, and a satisfactory rate of growth at protein intakes of 1.0-1.17 g kg-1. The values should prove useful guidelines for the management of infants requiring minimal intakes of protein. In studies carried out at 18-20 months of age, supplementation of the basic diet containing 0.75 g kg protein-1 with a mixture of amino acids not containing the precursors of methylmalonic acid was associated with increase of retention of nitrogen and increased concentrations of some essential amino acids in plasma, but effects on growth and the excretion of methylmalonic acid were not significant.

Amino Acid Metabolism, Inborn Errors↗
PubMed1985

Studies on requirements for amino acids in infants with disorders of amino acid metabolism. I. Effect of alanine.

Two infants with disorders of propionate metabolism were studied at 7 months of age to determine optimum levels of intake of protein and calories to meet the requirements for essential amino acid for growth in infancy, and at the same time minimize the accumulation of toxic intermediates. An effect of alanine was found that permitted growth at otherwise limiting levels of protein intake. This was not simply an effect of nonessential nitrogen as neither glycine nor glutamic acid could substitute for alanine in this protein-sparing effect. This appears to represent further evidence of the relationship between alanine and the branched-chain amino acids and of the importance of the alanine-glucose cycle in human physiology.

Alanine↗
PubMed1983

Dietary management of oculocutaneous tyrosinemia in an 11-year-old child.

An 11-year-old girl with keratitis and plantar keratosis had tyrosinemia. The concentration of tyrosine in the plasma was 16.5 mg/dL. Dietary intake of phenylalanine and tyrosine was systematically varied, and the plasma concentrations of tyrosine and nitrogen balance were studied. It was necessary to achieve a total intake of phenylalanine and tyrosine less than 100 mg/kg/day to obtain plasma concentrations of tyrosine of less than 10 mg/dL. After dietary therapy was started, the keratitis resolved promptly, and the patient remained asymptomatic during a period of 16 months in which the mean plasma concentration of tyrosine was 11.1 mg/dL. The dietary management of a child at this age presents a different problem from that of a young infant. It can be successfully pursued at home, as well as in the carefully regulated environment of a clinical research center.

Adolescent↗
PubMed1982

Lesch-Nyhan disease: clinical experience with nineteen patients.

The clinical phenotype in Lesch-Nyhan disease has been analyzed in 19 patients studied in hospital. In each case the diagnosis was made on the basis of inactivity of the enzyme hypoxanthine guanine phosphoribosyltransferase in erythrocyte lysates. All had hyperuricemia, and the presence of 'orange sand' in the diaper was a prominent early complaint. All had self-mutilative behavior, of which the most characteristic form was biting the fingers or lips. All had the neurological syndrome of spasticity and choreoathetoid involuntary movements. All but one had less-than-normal intelligence.

Adolescent↗