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Biomedical subjects

C B Whitley

Publications and source records attributed to C B Whitley.

51 records · Page 3Linked to original sources
PubMed1987

A nonpathologic allele (IW) for low alpha-L-iduronidase enzyme activity vis-a-vis prenatal diagnosis of Hurler syndrome.

We identified a phenotypically normal obligate heterozygote for Hurler syndrome with exceedingly low levels of alpha-L-iduronidase enzyme activity. Subsequent investigation determined that low alpha-L-iduronidase activity was systemic, also characteristic of the subject's leukocytes and cultured skin fibroblasts. Residual alpha-L-iduronidase activity of cultured fibroblasts was found to have reduced catalytic activity (Vmax) against the 4-methylumbelliferone substrate, but normal substrate affinity (KM). Additional studies further characterized the residual enzyme activity in this woman who is an apparent compound heterozygote for Hurler syndrome, and for an allele with low alpha-L-iduronidase activity lacking pathologic manifestation. Such low activity "pseudodeficiency" alleles will complicate attempts at prenatal diagnosis of Hurler syndrome and related disorders in rare families.

Adult↗
PubMed1987

Direct hyperbilirubinemia and hepatic fibrosis: a new presentation of Jeune syndrome (asphyxiating thoracic dystrophy).

Jeune syndrome (asphyxiating thoracic dystrophy) is an autosomal recessive skeletal dysplasia with multisystem involvement. The disorder is usually considered lethal, with death resulting from respiratory insufficiency during infancy, or from renal failure during childhood. Hepatic dysfunction, diagnosed on the basis of direct hyperbilirubinemia and hepatic fibrosis, led to early diagnosis of Jeune syndrome in a newborn infant. Review of the literature indicates that the specific pathologic lesion (biliary dysgenesis with portal fibrosis and bile duct proliferation) has been observed as an incidental finding at autopsy, but that clinically significant liver dysfunction has not been appreciated as an important manifestation in this disorder. The characteristic histopathologic abnormality has been present in every patient studied, and may advance during infancy; in contrast, clinical liver dysfunction resolves over the first few months of life. Whereas many patients with Jeune syndrome die early, several have survived into adolescence, suggesting that aggressive treatment is appropriate, especially for those with minimal respiratory and renal involvement. Longitudinal evaluation of liver function and pathology in these survivors is needed to define the long-term prognosis.

Asphyxia Neonatorum↗
PubMed1986

de la Chapelle dysplasia.

Since the description by de la Chapelle and colleagues of two sibs with a unique skeletal dysplasia, two additional cases have occurred, one in the original Finnish family and one sporadic patient born to unrelated parents of Belgian descent. The original Finnish family has later had a fourth child, a normal daughter who was found to be unaffected upon radiographic examination in the 19th week of gestation. These additional findings are compatible with recessive inheritance. Physical features common to these four patients include cleft palate, small thorax, moderately severe micromelia with small hands, and equinovarus deformity. In each case, the ulnae and fibulae were reduced to an almost triangular osseous remnant. Other long bones were short and bowed. Neonatal death occurred in all cases and may be attributed to a consistent triad of respiratory tract malformations: laryngeal stenosis, tracheobronchomalacia, and pulmonary hypoplasia. Clinical and radiographic features are sufficiently unique to distinguish de la Chapelle dysplasia from other disorders in the spectrum of neonatal lethal osteochondrodysplasias. Lacunar halos were identified as a distinctive histopathologic feature also observed in achondrogenesis but not in several other skeletal dysplasias.

Belgium↗
PubMed1985

Persistent succinylacetone excretion after liver transplantation in a patient with hereditary tyrosinaemia type I.

A liver transplant was performed on a 4-year-old female in liver failure caused by hereditary tyrosinaemia, with hepatocellular carcinoma following a negative evaluation for metastases. However, serum alpha-fetoprotein levels never returned to normal after the surgery. Urinary succinylacetone (SA) was detected in her urine prior to transplantation despite strict adherence to a low-tyrosine diet. Other patients with severe liver disease awaiting liver transplantation do not excrete SA in the urine. She continued to excrete SA during the postoperative period despite normal liver functions. Oral tyrosine loading resulted in significant elevation of SA excretion. Possible explanations for this observation and clinical and therapeutic relevance are discussed.

Carcinoma, Hepatocellular↗
PubMed1984

Fibrochondrogenesis: lethal, autosomal recessive chondrodysplasia with distinctive cartilage histopathology.

Fibrochondrogenesis is a rare, neonatally lethal rhizomelic chondrodysplasia distinguished from other forms of lethal dwarfism by broad long-bone metaphyses, pear-shaped vertebral bodies, and by microscopic changes of cartilage with unique interwoven fibrous septa and fibroblastic dysplasia of chondrocytes. We report the second and third well-documented cases of this apparently autosomal recessive disorder and discuss the differential diagnosis.

Cartilage↗
PubMed1984

Determination of urinary succinylacetone by capillary gas chromatography.

The average analytical recovery of succinylacetone added to urine and separated by capillary gas chromatography was 69% for solvent extraction and 72% for anion exchange separation. Treating succinylacetone with hydroxylamine hydrochloride at a pH of less than 5 caused formation of a derivative separated by capillary gas chromatography into two isomers: 3-methyl-5- isoxazole propionate and 5-methyl-3- isoxazole propionate as their trimethylsilyl derivatives (molecular weight 227). In a pH greater than or equal to 5, succinylacetone dioxime was formed and separated into 3 isomers as their trimethylsilyl derivatives (molecular weight 404). Succinylacetone dioxime was converted to 3(5)-methyl-(3)5- isoxazole propionate whenever the pH of the solution was dropped to less than 5. Mass spectra of both derivatives are shown. This study demonstrates that capillary gas chromatography is suitable for use in urinary succinylacetone determination.

Amino Acid Metabolism, Inborn Errors↗
PubMed1984

In vivo chloroquine-induced inhibition of insulin degradation in a diabetic patient with severe insulin resistance.

We report on a 26-yr-old patient with an 11-yr history of insulin-dependent diabetes mellitus who exhibited insulin resistance with a requirement of up to 15,000 U of intravenous (i.v.) insulin/day. Attempts to diminish her insulin requirement by administration of sulfated insulin or Trasylol were unsuccessful, with the patient remaining resistant to subcutaneous (s.c.) and i.v. administration of pure pork insulin. Chloroquine phosphate therapy (500 mg twice a day) resulted in a decreased requirement for i.v. insulin (700 U/day as compared with the pretreatment requirement of 8400 U/day). Accelerated insulin degradation in s.c. fat tissue of the patient before treatment with chloroquine was demonstrated. This activity was decreased by 64% during chloroquine therapy. Inhibition of insulin degrading activity (IDA) during chloroquine therapy was associated with reductions in the leukocyte lysosomal enzymes alpha-galactosidase and hexosaminidase-A but not hexosaminidase-B and beta-glucuronidase. This study constitutes the first reported use of chloroquine for treatment of insulin resistance as a result of accelerated insulin degradation, and it provides evidence of the effectiveness of this agent in this rare condition.

Adipose Tissue↗
PubMed1983

Warburg syndrome: lethal neurodysplasia with autosomal recessive inheritance.

Warburg syndrome is a recently recognized autosomal recessive neurodysplasia characterized by ventricular dilation, agyria, disorganized cortical cytoarchitecture, and dysgenesis of multiple other central nervous system structures. Because the disorder is lethal, with a 25% recurrence risk, it is crucial to distinguish Warburg syndrome from nonheritable phenocopies (caused by infectious agents and other teratogens) as well as from genetic disorders with a better prognosis. The clinical presentation of a markedly depressed newborn infant with hydrocephalus or ocular anomalies should suggest the diagnosis; computed tomography may be useful to demonstrate agyria as well as ventricular dilation. However, the distinctive neuropathologic finding of absent cerebral cortical lamination associated with numerous heterotopias appears to be diagnostic. Thus brain biopsy should be considered, especially at the time of ventricular shunting, whenever the clinical presentation suggests Warburg syndrome.

Abnormalities, Multiple↗
PubMed1983

Achondrogenesis: new nosology with evidence of genetic heterogeneity.

Achondrogenesis is a phenotypically diverse group of lethal osteochondrodysplasias characterized by severe micromelia, a short trunk, and a disproportionately large cranium. Cases of classic achondrogenesis Type I (Parenti-Fraccaro), and classic achondrogenesis Type II (Langer-Saldino) have been grouped on the basis of clinical, radiologic, and histopathologic features. Although further genetic heterogeneity has been proposed, broad acceptance has been lacking. Review of 79 cases, including examination of available radiographs of familial cases, permitted division into four radiographic prototypes. Cases were distinguished on the basis of specific skeletal features as well as a new parameter, the "femoral cylinder index" (CIfemur). Using these criteria, the affected siblings in 11 families were found to be concordant for prototype. Thus, identification of radiographic skeletal prototypes of achondrogenesis, and the observation of familial concordance for prototype, suggested the existence of at least four genetically distinct disorders, each having autosomal recessive transmission. These observations should provide further impetus for histopathologic and biochemical studies of the defects in achondrogenesis.

Achondroplasia↗
PubMed1983

Lenz-Majewski syndrome.

Lenz-Majewski syndrome is a rare disorder of unknown etiology. The condition is characterized by a disproportionately large head with large fontanels and widely separated sutures that close late. The head appears large relative to the reduced size of the trunk and limbs. The skin is loose, wrinkled, and atrophic with prominent veins, especially in the scalp. The ears are large and floppy, and frequently there is choanal atresia or stenosis, nasolacrimal duct obstruction, and, in boys, cryptorchidism and inguinal hernia. The disorder is characterized by failure to thrive and mental retardation. In contrast to craniometaphyseal and craniodiaphyseal dysplasias, the conditions most likely to be mistaken for this disorder, there does not appear to be any impingement on cranial nerves. The skeletal alterations are striking. The radiographic features include progressive sclerosis of the skull, facial bones, and vertebrae; broad clavicles and ribs; short or absent middle phalanges; diaphyseal undermodeling and midshaft cortical thickening; metaphyseal and epiphyseal hypostosis; and retarded skeletal maturation. Tooth enamel is also defective.

Abnormalities, Multiple↗
PubMedDate not supplied

Closed hollow-fiber bioreactor: a new approach to retroviral vector production.

BACKGROUND: The ability to obtain high-titer and large quantities of retroviral vector production in a 'closed' system would have profound implications in clinical and experimental gene therapy. METHODS: We studied the cell growth and vector production of three retroviral packaging cell lines in a variety of conditions using hollow-fiber bioreactors designed as an 'artificial capillary system' (ACS) and enhanced with the application of a hermetically sealing device for sterile welding of connecting plastic tubings. Vector titer, fetal bovine serum (FBS) concentration, volume and the duration of productivity were assessed to optimize vector production. RESULTS: In this pilot study, we observed that retroviral vector production (frozen-and-thawed) from cultures containing as low as 2.5% FBS yielded titers up to 2.2 x 10(7) cfu/ml, 14.4-fold higher than titers obtained from control dish cultures. Up to 3 liters of vector supernatant were generated during a 2-month large-scale production run. There was a potential to double this volume of higher-titer supernatant by increasing the frequency of harvest. It seemed that a lower metabolic rate (i.e. lactate production) in the packaging cell culture was associated with higher vector producing ability. CONCLUSIONS: These data demonstrated the feasibility of producing retroviral vector with enhanced titers and clinically useful quantities in a 'closed' ACS. Thus a new approach for large-scale retroviral vector production is developed.

Animals↗