Renal disease in type I glycogen storage disease

Although kidney enlargement occurs in Type I glycogen storage disease, renal disease has not been considered a major problem. Death from renal failure in three patients known to us prompted a study of renal function in this disorder. Of the 38 patients with Type I glycogen storage disease under our care, the 18 children under 10 years old had normal renal function. Fourteen of the 20 older patients (13 to 47 years) had disturbed renal function, manifested by persistent proteinuria; many also had hypertension, hematuria, or altered creatinine clearance. Progressive renal insufficiency developed in 6 of these 14 patients, leading to three deaths from renal failure. At the onset of proteinuria, creatinine clearance was increased in seven patients (3.05 +/- 0.68 ml per second per 1.73 m2 of body-surface area; range, 2.47 to 4.13 [normal range, 1.33 to 2.33 ml per second per 1.73 m2]). Renal biopsies were performed in three patients after an average of 10 years of proteinuria. All three biopsies demonstrated focal segmental glomerulosclerosis in various stages of progression. Our data suggest that chronic renal disease is a frequent and potentially serious complication of Type I glycogen storage disease. In addition to treating hypoglycemia vigorously, physicians should monitor renal function carefully in patients with this disorder.

Glycogen debranching enzyme: purification, antibody characterization, and immunoblot analyses of type III glycogen storage disease

Type III glycogen storage disease is caused by a deficiency of glycogen debranching-enzyme activity. Many patients with this disease have both liver and muscle involvement, whereas others have only liver involvement without clinical or laboratory evidence of myopathy. To improve our understanding of the molecular basis of the disease, debranching enzyme was purified 238-fold from porcine skeletal muscle. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis the purified enzyme gave a single band with a relative molecular weight of 160,000 that migrated to the same position as purified rabbit-muscle debranching enzyme. Antiserum against porcine debranching enzyme was prepared in rabbit. The antiserum reacted against porcine debranching enzyme with a single precipitin line and demonstrated a reaction having complete identity to those of both the enzyme present in crude muscle and the enzyme present in liver extracts. Incubation of antiserum with purified porcine debranching enzyme inhibited almost all enzyme activity, whereas such treatment with preimmune serum had little effect. The antiserum also inhibited debranching-enzyme activity in crude liver extracts from both pigs and humans to the same extent as was observed in muscle. Immunoblot analysis probed with anti-porcine-muscle debranching-enzyme antiserum showed that the antiserum can detect debranching enzyme in both human muscle and human liver. The bands detected in human samples by the antiserum were the same size as the one detected in porcine muscle. Five patients with Type III and six patients with other types of glycogen storage disease were subjected to immunoblot analysis. Although anti-porcine antiserum detected specific bands in all liver and muscle samples from patients with other types of glycogen storage disease (Types I, II, and IX), the antiserum detected no cross-reactive material in any of the liver or muscle samples from patients with Type III glycogen storage disease. These data indicate (1) immunochemical similarity of debranching enzyme in liver and muscle and (2) that deficiency of debranching-enzyme activity in Type III glycogen storage disease is due to absence of debrancher protein in the patients that we studied.

Cloning of a brain protein identified by autoantibodies from a patient with paraneoplastic cerebellar degeneration

Autoantibodies directed against neuronal proteins have been identified in some patients with paraneoplastic cerebellar degeneration. To identify the molecular targets for these autoantibodies, we constructed a lambda gt11 cDNA expression library from human cerebellum and screened the library with IgG from a patient with paraneoplastic cerebellar degeneration. A single clone, pCDR2, produced a fusion protein that reacted strongly with the patient's IgG. The isolated pCDR2 clone was used to identify six overlapping cDNA clones. Sequencing of the pCDR clones revealed a distinctive pattern consisting of a unit of 18 nucleotides (6 amino acids) repeated in tandem along the entire cDNA sequence. This sequence is unlike any previously described eukaryotic gene. Southern blot analysis was consistent with single-copy representation of the CDR (cerebellar degeneration-related) gene in the human and mouse genome. RNA blotting studies with normal tissues showed expression of the CDR gene to be largely restricted to brain. Expression of the CDR message was also noted in cell lines derived from cancers of neuroectodermal, kidney, and lung origin.

5'-structural analysis of genes encoding polymorphic antigens of chemically induced tumors

We have proposed that the distinct tumor rejection antigens of chemically induced sarcomas in inbred mice belong to a family of Mr 96,000 glycoproteins (gp96). An identical 14-amino acid sequence was found at the amino terminus of gp96 from two antigenically distinct BALB/c sarcomas. Oligonucleotide probes derived from this sequence permitted isolation of 5' cDNA and genomic fragments coding for gp96. Three short exons interrupted by relatively long introns were identified at the 5' terminus of the gp96 gene. The first exon encodes a signal peptide, which is consistent with gp96 being a cell surface antigen. Southern blot analysis indicated that the gp96 family is encoded by a single gene, and 3-kilobase transcripts were detected in all normal and tumor cells tested. Nucleotide and deduced amino acid sequences from 311 base paris at the 5' terminus showed no homology with any known protein. The availability of molecular probes for the gp96 system permits analysis of the structural polymorphism of these antigens.

Wrist extensor recovery in traumatic quadriplegia

Wrist extensor recovery is of major functional significance in many quadriplegic patients. In this retrospective study, we investigated a method for prognosticating wrist extensor recovery and the underlying mechanisms for improvement in strength. Thirty-five quadriplegic patients at the C4, C5, and C6 neurologic levels, admitted over a four-year period, were examined at one week, two months, and eight months postinjury for biceps and wrist extensor strength. Initial biceps strength was compared to final wrist extensor strength. All 16 C5 patients whose initial biceps strength was grade 3 showed wrist extensor improvement to grade 3; only three of 16 C4 patients showed the same improvement. We concluded that initial biceps strength is a reliable indicator of wrist extensor recovery, and most, if not all, C5 neurologic patients will gain one full motor level. This improvement may be due to compensatory factors, such as overwork hypertrophy and peripheral sprouting of nerves within the muscle, rather than to recovery of a root level.

Left ventricular diastolic function in hypertrophic cardiomyopathy: assessment by radionuclide angiography

Diastolic left ventricular function was studied in 20 patients with obstructive hypertrophic cardiomyopathy, 10 with apical hypertrophic cardiomyopathy, and 20 control subjects. The left ventricular time-activity curve was filtered using Fourier expansion with 4 harmonics. The first and second derivatives of the filtered curve were used to define various parameters of the left ventricle. Isovolumic relaxation period and time to peak filling rate were prolonged in obstructive hypertrophic cardiomyopathy and apical hypertrophic cardiomyopathy (101.56 +/- 44.81 msec, 105.19 +/- 45.27 versus 72.19 +/- 29.36 (CS) P less than 0.05; 169.70 +/- 50.73 msec, 173.83 +/- 50.53 versus 138.02 +/- 29.54 (CS) P less than 0.05, respectively). Rapid filling period, diastasis, atrial contraction period, time to peak filling rate-isovolumic relaxation period, and filling fraction of diastasis were not significantly different in these groups. Fasting filling fraction was 11% lower in hypertrophic groups than in control subjects. The filling fraction of atrial contribution was 12% higher in hypertrophic groups. We conclude: Isovolumic relaxation period, rapid filling phase, and diastasis atrial contraction period can be clearly defined by this technique. Impaired relaxation is an important determinant of decreased left ventricular filling in patients with obstructive hypertrophic cardiomyopathy and apical hypertrophic cardiomyopathy. Prolonged time to peak filling rate is mainly due to increased isovolumic relaxation period in hypertrophic patients. Atrial contraction contributes to more stroke volume in patients with hypertrophic cardiomyopathy.

Vitamins E and K induce aryl hydrocarbon hydroxylase activity in human cell cultures

Two fat soluble vitamins, Vitamins E and K, when added into culture medium, were found to increase aryl hydrocarbon hydroxylase activity in human cultured cells. The extent of induction in a hepatoma-derived cell line (Hep G2) by these vitamins is of similar magnitude to those cells receiving benz[a]anthracene; whereas in a mammary tumor-derived cell line (MCF-7), benz[a]anthracene is the best inducer for the hydroxylase activity. The increase of the hydroxylase activity is associated with increased levels of a specific mRNA coding for polynuclear aromatic hydrocarbons-induced form of cytochrome P-450 with Vitamins E and K treatment. The size of the induced mRNA is 3.3 kilobase which is the same as that of benz[a]anthracene treatment.

Expression and chromosomal localization of the cytochrome P1-450 gene in human mitogen-stimulated lymphocytes

Genetic differences in aryl hydrocarbon hydroxylase (AHH) (flavoprotein-linked monoxygenase EC 1.14.14.1) activity in cultured lymphocytes have been linked with individual risk for certain environmentally caused cancers. Cytochrome P1-450 is the form of cytochrome P-450 most closely associated with AHH activity. In this study the chromosomal localization and the expression of human cytochrome P1-450 gene were determined in phytohemagglutinin-stimulated lymphocytes. In situ hybridization analysis provides assignment of the structural gene for human cytochrome P1-450 to chromosome 15q22-q24. Treatment of lymphocytes with benzanthracene increased the amount of mRNA hybridized to the cloned cytochrome P1-450 gene. The level of cytochrome P1-450 mRNA in these lymphocytes correlates well with the induced AHH activity indicating that non-cytochrome P1-450 enzymes contribute little to the individual differences in the level of AHH activity in the lymphocytes. Southern analyses of genomic DNA from individuals with high and low induced AHH activity demonstrated no detectable differences in the pattern or intensity of restriction fragments after treatment with benzanthracene from either individual. This finding together with the excellent correlation between the induced cytochrome P1-450 and AHH activity, suggests that transcriptional control rather than gene amplification or gross form of gene rearrangement accounts for cytochrome P1-450 induction in man. Measurements of cytochrome P1-450 mRNA content in cultured lymphocytes provide an alternative approach to the assay of AHH activity in assessing AHH phenotype and predicting different susceptibilities to deleterious environmental agents.

Thymus-leukemia (TL) antigens of the mouse. Analysis of TL mRNA and TL cDNA TL+ and TL- strains

A thymus-leukemia (TL)-specific probe, pTL1, has been generated from a TL-coding gene of BALB/c mice. Multiple species of TL mRNA were detected in TL+ cells by Northern blot analysis with pTL1, and different Tla haplotypes could be distinguished on the basis of characteristic patterns of TL mRNA. No TL-related message was found in normal or leukemic TL- cells, including thymocytes from Tlab mice. However, TL mRNA could be detected in TL+ leukemias occurring in Tlab mice. A cDNA library has been made from ASL1 (a TL+ leukemia of A mice [Tlaa]), and pTL1+ clones have been sequenced. At least three structurally distinct TL genes are expressed in ASL1. Sequence comparison of TL genes from three Tla haplotypes indicates that TL genes are highly conserved (greater than 90% homology) and are more distantly related to H-2 genes. Several polyadenylation sites have been found in the 3' untranslated region of TL genes, and differential polyadenylation contributes to the size heterogeneity of TL transcripts. The predicted amino acid sequence of TL products indicates that TL and H-2 are similar in domain structure and disulfide bonds, but differ in glycosylation sites and in cytoplasmic domain sequences.

Identification and quantification of a messenger ribonucleic acid induced by polynuclear aromatic hydrocarbons--using a cloned human cytochrome P-450 gene

We have isolated four overlapping human genomic clones associated with the polynuclear aromatic hydrocarbon-induced form of cytochrome P-450. The form of P-450 most closely associated with polynuclear aromatic hydrocarbons induction has been defined as P1-450. These four overlapping genomic clones span a total of 31.0 X 10(3) base pairs in length with the coding sequence lying in the center of these clones. Translation in vitro of 3-methylcholanthrene-induced mRNA, selected with the human P1-450 genomic clone, detect a protein with Mr 52000, which is immunoprecipitable by the anti-(mouse P1-450) antibody. The isolated human P1-450 genomic clone hybridizes to 3-methylcholanthrene-induced mRNA from monkey liver, benzanthracene and 3-methylcholanthrene-treated human mammary tumor cells (MCF-7), but not to isosafrole-treated human cells. Upon treatment with polynuclear aromatic hydrocarbons there is a positive correlation between induced arylhydrocarbon hydroxylase (flavoprotein-linked monoxygenase) activity and the amount of mRNA that hybridizes to the isolated human genomic clone for P1-450. The size of mRNA, induced from human cells and monkey liver by polynuclear aromatic hydrocarbons, is around 3.3 X 10(3) base pairs, which is the same as the larger of two mRNA induced by polynuclear aromatic hydrocarbons in the inbred strain of mouse (C57BL/6N). Our data also showed that the isolated DNA clone can detect a mRNA size of 3.3 X 10(3) base pairs from phytohemagglutinin-activated, benzanthracene-treated human lymphocytes. Densitometer scanning indicated the presence of a 3.6-fold variation (highest-lowest) in the levels of lymphocyte P1-450 mRNA contents among six individuals studied.

Liver-specific glucose-6-phosphatase is not present in human placenta

Type I glycogen storage disease (McKusick 23220), an inherited absence or deficiency of glucose-6-phosphatase (EC 3.1.3.9) activity in the liver, kidney and intestine, is associated with the accumulation of glycogen in those organs. Previous reports have shown that glucose-6-phosphatase exists in human placenta and that detection of a heterozygote for this disorder from placenta might be possible. Our finding of a normal glucose-6-phosphatase activity in a placenta from a patient at risk for type Ia glycogen storage disease prompted us to examine in more detail placental glucose-6-phosphatase. Unexpectedly, we found the properties of the placental enzyme differed from that in normal liver, and the placental enzyme hydrolyzed glucose-6-phosphate, mannose-6-phosphate, beta-glycerol phosphate and glucose-1-phosphate equally well. Our data suggest the enzyme deficient in type I glycogen storage disease cannot be detected in placenta.