Inheritance of UMP synthase in dairy cattle

The inheritance of uridine-5'-monophosphate (UMP) synthase in dairy cattle was consistent with a two-allele, single-autosomal-locus model. Two phenotypes were associated with different levels of the enzyme in bovine erythrocytes. The predominant phenotype (assumed normal) had twice the concentration of UMP synthase as the second phenotype (deficient). A one-to-one correspondence between enzyme level and genotype identified one homozygote as normal, the heterozygote as deficient, and the other homozygote as unobserved. Three alternative hypotheses were rejected. The deficiency as homozygous recessive was rejected because 20 matings between assumed normal males and deficient females resulted in 10 normal and 10 deficient offspring. The hypothesis that the deficiency was homozygous dominant was rejected because the 95 percent confidence interval about the observed gene frequency, 0.0024 to 0.0146, did not contain the estimated gene frequency for equilibrium between an average 10(-5) mutation rate and selection against the deficiency as homozygous dominant. Analyses of female relatives implicated one bull as deficient (96 percent probability), as he had, independently, 2 deficient daughters, 5 deficient granddaughters from untested dams, and 3 deficient great-granddaughters from untested ancestors. The hypothesis that the deficiency was sex-linked was rejected because 3 of 9 tested sons of the putative deficient bull were deficient. Calf mortality is expected in 25 percent of matings between deficient animals.     

Oro-maxillofacial development in patients with GH deficiency and in normal short children

Detailed oro-maxillofacial studies using dental cast, pantomogram and cephalogram were performed in 43 patients with GH deficiency aged 7-17 years and compared statistically to the results from 62 short children with normal GH secretion. The dental age was retarded as compared to the chronological age in patients with GH deficiency by a mean of 2.0 +/- 1.3 years. This value did not differ statistically from that observed in normal short children (1.7 +/- 0.8 years). However the bone age was significantly retarded in patients with GH deficiency (3.2 +/- 1.7 yrs vs 1.5 +/- 1.1 yrs, p less than 0.001). There was no difference between tooth size or cephalogram analysis results in the children in the two groups. The coronal arch length, basal arch width and basal arch length were shorter in patients with GH deficiency. These data indicate underdevelopment of the maxilla in patients with GH deficiency.     

A Combination Inversion and Translocation in Neurospora Crassa with Inviable Deficiency Progeny That Can Be Rescued in Heterokaryons

Chromosome rearrangement In(IL;IR)T(IL;IIIR)SLm-1, has a pericentric inversion in linkage group I associated with a reciprocal translocation between I and III. The rearrangement was identified cytologically in pairing with normal sequence chromosomes at pachynema. Rearrangement breakpoints were mapped genetically in IL, IR and IIIR by crosses with normal sequence strains and in crosses with an inversion that partially overlaps the SLm-1 inversion. When rearrangement SLm-1 is crossed to parents with normal sequence chromosomes, one class among the progeny has a small chromosome deficiency and large duplication. The ascospores containing this deficiency/duplication die either before germination or just after, when growth commences. Germ tubes of the deficiency/duplication progeny, which start to grow then stop, resemble the aborted growth of auxotrophic mutants germinated on minimal medium. Efforts to correct the deficiency with nutritional supplements were not successful. However, the defective class can be rescued by fusing the germinating hyphae of the deficiency ascospore with a complementary auxotrophic mutant to form a heterokaryon. A deficiency/duplication nucleus that is rescued in a heterokaryon can serve as a fertilizing nucleus in crosses with a normal sequence parent. One half of their progeny have the normal chromosome sequence and one half have the chromosome deficiency syndrome and die at germination.     

Liver lipids of choline-deficient rats

1. Four-week-old male and female rats were given choline-deficient diets for 2 weeks. Deficient animals gained nearly as much weight as normal controls of the same sex. 2. The amounts of triglyceride and esterified cholesterol in liver lipids were increased threefold or more by the deficiency. The amounts of the major phosphatides and of unesterified cholesterol were unaffected. 3. In males, deficiency significantly increased the proportion of stearic acid in triglycerides, and, in females, the proportion of arachidonic acid was significantly decreased. 4. In the phospholipids of male rats, choline deficiency produced decreases in the amounts of linoleic acid and arachidonic acid and increased the amount of stearic acid. In the phospholipids of female rats, choline deficiency decreased the amount of arachidonic acid and increased that of linoleic acid. 5. The liver phospholipids of normal male rats had higher proportions of palmitic acid and lower proportions of stearic acid than were found in normal females. These sex differences became statistically insignificant in deficient animals.     

Defective enzyme causes lecithin-cholesterol acyltransferase deficiency in a Japanese kindred

Lecithin-cholesterol acyltransferase mass levels and activity and apolipoproteins A-I, A-II, B and D were measured in a Japanese family who have a familial lecithin-cholesterol acyltransferase deficiency. This analysis was performed to gain insight into the molecular basis of the enzyme deficiency and to compare findings in this family with other families with familial lecithin-cholesterol acyltransferase deficiency. The mass of the enzyme in plasma was determined by a sensitive double antibody radioimmunoassay, and enzyme activity was measured by using a common synthetic substrate comprised of phosphatidylcholine, cholesterol and apolipoprotein A-I liposomes prepared by a cholate dialysis procedure. The lecithin-cholesterol acyltransferase-deficient subject had an enzyme mass level that was 35% of normal (2.04 micrograms/ml, as compared with an average normal level of 5.76 +/- 0.95 micrograms/ml in 19 Japanese subjects) and an enzyme activity of less than 0.1% of normal (0.07 nmol/h per ml, as compared with normal levels of 100 nmol/h per ml). This subject also had lower levels of apolipoproteins: apolipoprotein A-I was 53 mg/dl (42% of normal), apolipoprotein A-II was 10.6 mg/dl (31% of normal), apolipoprotein B was 68 mg/dl (68% of normal), and apolipoprotein D was 3.6 mg/dl (60% of normal). The three obligate heterozygotes had enzyme mass levels ranging from 65% to 100% of normal and enzyme activity levels ranging from 23% to 65% of normal (23.4, 56.8, and 64.7 nmol/h per ml, respectively). The proband's sister had an enzyme mass level of 6.55 micrograms/ml (114% of normal) and an enzyme activity of only 64.8 nmol/h per ml (65% of normal), suggesting that she was also a heterozygote for lecithin-cholesterol acyltransferase deficiency. The obligate heterozygotes and the sister had normal apolipoprotein levels. We conclude that the lecithin-cholesterol acyltransferase deficiency in this family is due to the production of a defective enzyme that is expressed in the homozygote as well as in the heterozygotes, and, further, that this family's mutation differs from that reported earlier for other Japanese lecithin-cholesterol acyltransferase-deficient families.     

Genetic complementation in somatic cell hybrids of cerebroside sulfatase activator deficiency and metachromatic leukodystrophy fibroblasts

Summary Several cases of metachromatic leukodystrophy (MLD) have been described with normal or near normal activities of arylsulfatase A (cerebroside sulfatase). However, the ability of intact cultured fibroblasts to hydrolyze cerebroside sulfate was impaired. Since the impairment was corrected by cerebroside sulfatase activator, a deficiency of activator was implied. In the absence of direct demonstration of deficiency, other types of evidence were needed to support the premise that the genetic defect was not associated with the arylsulfatase A locus as in classical MLD. Therefore, somatic cell hybrids of activator deficiency and MLD fibroblasts were analyzed. Complementation was indicated by enhanced hydrolysis of cerebroside sulfate, supporting the view that cerebroside sulfatase activator deficiency and MLD are nonallelic.     

Hepatic methionine adenosyltransferase deficiency in a 31-year-old man.

A 31-year-old man with hepatic methionine adenosyltransferase (MAT) deficiency was evaluated for an odd odor to his breath. He had no other symptoms. Plasma methionine was 716 microM (normal, 15-40 microM), and plasma methionine-oxidation products were 460 microM (normal, 0). Hepatic MAT activity was 28% of normal. Unlike the control human enzyme, the patient's residual MAT activity was not stimulated by 10% dimethylsulfoxide and the velocity was not increased by high substrate concentration; at 1.0 mM methionine, the patient's MAT activity was only 7% of normal. These biochemical findings are consistent with a deficiency of the high-Km isoenzyme of MAT. Despite this enzyme deficiency, liver histology and clinical tests of hepatic and other organ function were normal. The patient, who is 25 years older than the oldest reported individual with MAT deficiency, provides evidence that partial MAT deficiency is a benign disorder and that chronic hypermethioninemia (less than 1 mM) is not by itself detrimental to health.     

Intracellular free magnesium and phosphorylated metabolites in hexokinase- and pyruvate kinase-deficient red cells measured using 31P-NMR spectroscopy

The erythrocyte metabolism of two patients with nonspherocytic hemolytic anemia caused by a hexokinase deficiency, and a pyruvate kinase deficiency, respectively, were studied with NMR. The complexing of ATP and 2,3-diphosphoglycerate (2,3-DPG) with Mg2+ and hemoglobin (Hb) was determined using 31P-NMR on oxygenated and deoxygenated cells to investigate the influences of these enzyme defects on intracellular magnesium distribution and on Hb oxygen dissociation. In the pyruvate kinase-deficient red blood cells, the 2,3-DPG concentration was almost twice the normal value and the ATP concentration was near the lower limit of the normal range. In the hexokinase-deficient red cell population, the predominance of young cells masked the deficiency. Therefore, reticulocyte control cells were included in this study. In the oxygenated pyruvate kinase-deficient cells, the fraction of ATP that is complexed to magnesium as well as the free Mg2+ concentration were normal, despite the abnormal concentration of 2,3-DPG. In the deoxygenated cells the free Mg2+ concentration was lower than in normal cells. The fraction of Hb complexed with 2,3-DPG was higher than normal in both oxygenated and deoxygenated pyruvate kinase-deficient cells, in accordance with the high p50 of the oxygen-hemoglobin dissociation curve. In hexokinase-deficient cells, two major abnormalities are found: when the cells were deoxygenated, the concentration of ATP and 2,3-DPG fell. This was not observed for any other sample and could, therefore, be a consequence of the hexokinase deficiency. Despite almost normal levels of magnesium-binding metabolites, the free Mg2+ concentration in oxygenated and deoxygenated cels is much lower than in normal cells. This could be a cell-age-related phenomenon, since lower free Mg2+ concentrations were also found in reticulocyte control cells.     

Riboflavin nutritional status and flavoprotein enzymes in streptozotocin-diabetic rats

Riboflavin nutritional status was assessed on the basis of activity coefficients of glutathione reductase in erythrocyte hemolysates of normal and streptozotocin-diabetic rats. Activity coefficient values higher than 1.3 were regarded as evidence of riboflavin deficiency. All diabetic animals were found to be riboflavin-deficient, with activity coefficient values of 1.47–2.11. Treatment of diabetic rats with either insulin or riboflavin returned their activity coefficients to normal. Rats fed a restricted diet had normal activity coefficient values. The erythrocyte glutathione reductase activity was significantly lower in diabetic rats, and the augmentation of enzyme activity in the presence of flavin-adenine dinucleotide (FAD) was 72% compared to 16% in normal rats. Hepatic activities of glutathione reductase and succinate dehydrogenase, both FAD-containing enzymes, were significantly lower in diabetic than in normal rats. Like activity coefficient values, all enzyme activities were normalized after insulin or riboflavin treatments. These data suggest that insulin and riboflavin enhance the synthesis of erythrocyte and hepatic FAD. The results of the present study suggest that experimental diabetes causes riboflavin deficiency, which in turn decreases erythrocyte and hepatic flavoprotein enzyme activities. These changes can be corrected for by either insulin or riboflavin. The pathogenesis of riboflavin deficiency in diabetes mellitus is not clearly understood. The data of the present study provide evidence in addition to the previous findings of an increased prevalence of riboflavin deficiency in genetically diabetic KK mice.     

Serum thyrotropin response to thyrotropin-releasing hormone and free thyroid hormone indices in patients with familial thyroxine-binding globulin deficiency.

The response in serum thyrotropin (TSH) to synthetic thyrotropin-releasing hormone (TRH) as well as serum free thyroxine index (FT4I) and free triiodothyronine index (FT3I) was investigated in six patients with familial thyroxine-binding-globulin (TBG) deficiency. The total serum thyroxine (T4) and triiodothyronine (T3) concentrations were significantly decreased, compared with those of normal subjects (3.4 +/- 0.9 microgram/dl, mean +/- SD. vs. 9.0 +/- 1.5 microgram/dl, p less than 0.01 and 87 +/- 27 ng/dl vs. 153 +/- 37 ng/dl, p less than 0.01, respectively). FT4I was lower than the normal range in all but one (5.3 +/- 1.5 vs. 8.9 +/- 1.6, p less than 0.01), whereas FT3I was all in the normal range and of no significant difference from the normal control (132 +/- 22 vs. 148 +/- 25). Serum TSH concentrations in TBG deficiency were all in the normal range (1.0-4.2 muU/ml) and the maximum TSH increments following TRH 500 microgram iv were 8.9 +/- 2.0 muU/ml and of no significant difference from the normal control (10.2 +/- 4.5 muU/ml). These results indicate that the euthyroid state in familial TBG deficiency is more clearly defined by TRH-test and the normal response to TRH in familial TBG deficiency is presumably under the control of the serum free T3 level rather than the serum free T4 level.     

Effects of essential fatty acid deficiency on mitochondria and peroxisomes in rat hepatocytes with special reference to a partially hydrogenated fish oil diet

Feeding male rats a high cal% partially hydrogenated fish oil diet induced morphological and biochemical changes in hepatocytes at the mitochondrial and peroxisomal level. At the mitochondrial level, formation of megamitochondria was related to the development of an essential fatty acid deficiency, as measured by a high 20:3/20:4 fatty acid ratio. These mitochondrial changes were fully prevented by adding linoleic acid to the partially hydrogenated fish oil diet. The megamitochondria revealed a normal specific content of respiratory chain pigments, normal specific respiratory rates and a normal energy coupling. At the peroxisomal level, feeding of the partially hydrogenated fish oil diet caused a considerable proliferation, which was unrelated to essential fatty acid deficiency. The total number of peroxisomes increased 1.9-fold, and 2.6-fold in the presence of added linoleic acid. Essential fatty acid deficiency seemed to result in an inhibition of peroxisomal biogenesis. It was concluded that the induction of megamitochondria by partially hydrogenated fish oil was fully attributable to essential fatty acid deficiency, whereas peroxisomal proliferation must be attributed to other factors in the diet.     

The effect of selenium on the hepatic drug metabolism and inducibility in rat

1. Rats were fed either a normal or selenium-deficient diet for 4 weeks. The subgroup on selenium deficient diet had selenium supplementation as 3 ppm Se in the drinking water. Benzo(a)pyrene was given intraperitoneally as an inducer. 2. Se deficiency decreased glutathione peroxidase and cytochrome c-reductase activities while other activities were unchanged as compared to normal diet. 3. Selenium deficiency was a prerequisite for the induction of glutathione peroxidase, S-reductase and S-transferase enzymes. 4. Benzo(a)pyrene increased hepatic microsomal cytochrome P-450 content in rats on normal and selenium supplemented diet but not in the selenium deficient group. 5. The 7-ethoxyresorufin and 7-ethoxycoumarin deethylase, aryl hydrocarbon hydroxylase and cytochrome c-reductase activities were increased by benzo(a)pyrene in all the dietary groups. 6. The UDP-glucuronosyltransferase activity was also increased by benzo(a)pyrene in all the experimental groups and this was true with p-nitrophenol and phenolphthalein as aglycons.     

Hepatic drug hydroxylation and lipid peroxidation in riboflavin-deficient rats

The effect of riboflavin deficiency and phenobarbital pretreatment on drug hydroxylation and lipid peroxidation was investigated. A significant decrease in aniline and acetanilide hydroxylation as well as NADPH-linked and ascorbate-induced lipid peroxidation was observed during 4- and 7-week riboflavin deficiency in both adult male and adult female rats. The drug-hydroxylation and lipid-peroxidation activities were further lowered with the increase in riboflavin deficiency. The phenobarbital pretreatment induced aniline and acetanilide hydroxylase activity even in riboflavin-deficient animals. Drug hydroxylation inhibits lipid peroxidation in both deficient and normal rats. The administration of riboflavin was followed by a significant increase in drug hydroxylation and lipid peroxidation.     

Evidence that hepatic lipase deficiency in humans is not associated with proatherogenic changes in HDL composition and metabolism

The aim of the present study was to characterize the composition and metabolism of HDL in subjects with complete hepatic lipase (HL) deficiency. Analyses were carried out in three complete and three partial HL-deficient subjects as well as in eight normotriglyceridemic (NTG) and two hypertriglyceridemic controls. Complete HL deficiency was associated with hypertriglyceridemia and with a 3.5-fold increase in HDL-triglyceride (TG) levels. The in vivo kinetics of apolipoprotein A-I (apoA-I) and apoA-II (d < 1.25 g/l) were studied in the fasted state using a primed-constant infusion of l-(5,5,5-D3)leucine for 12 h. Complete HL deficiency was associated with a reduced fractional catabolic rate of apoA-I in the HL-deficient female proband (-47%) and in her two brothers (-21%) compared with gender- and TG-matched controls. Total plasma and HDL from complete HL-deficient patients were able to mediate normal cholesterol efflux from human skin fibroblasts labeled with [3H]cholesterol. Complete HL deficiency was also associated with normal levels of prebeta-migrating apoA-I-containing HDL separated by two-dimensional gel electrophoresis and with an accumulation of large HDL particles compared with NTG controls. These results suggest that HL activity is important for adequate HDL metabolism, although its presence may not be necessary for normal HDL-mediated reverse cholesterol transport.     

Biochemical studies of canine muscle phosphofructokinase deficiency

Skeletal muscle from four dogs with erythrocyte phosphofructokinase (PFK; EC 2.7.1.11) deficiency were studied in vitro. Muscle PFK activities were severely decreased to 1% of the normal mean. The residual activities had a high Km for fructose-6-phosphate (F6P). Anaerobic lactate production of PFK-deficient muscle was minimal with the addition of glycogen and hexose-monophosphates, but was normal with fructose-1,6-diphosphate (FDP). Muscle glycogen concentration was twice normal, indicating a glycogen storage disorder. Histochemical studies for muscle PFK activity showed no enzymatic staining with F6P as substrate. In two muscle biopsies from asymptomatic related dogs, intermediate PFK activities were found. These data characterize canine muscle PFK deficiency in vitro.     

Deficiency of a 42-kilodalton protein in tumor-derived fibroblastic cells in neurofibromatosis

Cell proteins obtained from cultured normal appearing skin and neurofibromas of neurofibromatosis patients, and normal skin of normal donors were compared by SDS-PAGE and isoelectric focusing analysis. Essentially, identical protein patterns were obtained for the pellet fractions of all the strains. The lysate fraction binding patterns were also similar to each other, but a deficiency of a 42-kilodalton protein with pI 4.3 was observed in the four tumor-derived cell strains examined. These results raise the possibility that tumor-derived fibroblastic cells are of the same cell origin as skin fibroblasts, and that the deficiency of a 42-kilodalton protein could be related to the tumorigenicity in neurofibromatosis.     

High frequency of-β-hexosaminidase deficiency in lymphoblastoid cell lines

The activity of seven lysosomal enzymes was determined in 25 lymphoblastoid cell lines. These lines included normal controls transformed with Epstein-Barr virus, Burkitt's lymphomas and other lymphomas with or without EBV genome.Four lines were deficient in total β-hexosaminidase activity. The deficiency was as severe as that of the variant O (Sandhoff's disease) of clinical β-hexosaminidase deficiency. The electrophoretic pattern was also similar to that observed in Sandhoff's disease.The possible mechanisms explaining the high frequency of β-hexosaminidase deficiency in lymphoblastoid cell lines are discussed.     

Late-onset 21-hydroxylase deficiency is an allelic variant of congenital adrenal hyperplasia characterized by attenuated clinical expression and different HLA haplotype associations

Three families with late-onset 21-hydroxylase deficiency were studied. Homozygous females presented with symptoms of mild hyperandrogenism such as acne, hirsutism, oligomenorrhea and menometrorrhagia. A homozygous male was asymptomatic and had reached normal adult height. The diagnosis of 21-hydroxylase deficiency was based upon markedly elevated responses of plasma 17-hydroxyprogesterone during a short (30-min) ACTH infusion test. The propositi of two of the families were diagnosed despite long-standing glucocorticoid therapy and adrenal suppression by using a prolonged (48-hour) ACTH infusion. Heterozygotes of late-onset 21-hydroxylase deficiency had mildly elevated 17-hydroxy-progesterone responses to ACTH. Late-onset 21-hydroxylase deficiency was inherited as an autosomal recessive trait with close linkage to the histocompatibility leukocyte antigens. The B14 haplotype was present in all affected members. One affected female had a daughter with classic, salt-losing 21-hydroxylase deficiency. Mixed heterozygosity of this patient for a classic and a late-onset 21-hydroxylase deficiency allele may have caused the classic phenotype in her daughter (homozygote for 2 classic alleles).     

Mutations and phenotype in isolated glycerol kinase deficiency.

We demonstrate that isolated glycerol kinase (GK) deficiency in three families results from mutation of the Xp21 GK gene. GK mutations were detected in four patients with widely differing phenotypes. Patient 1 had a splice-site mutation causing premature termination. His general health was good despite absent GK activity, indicating that isolated GK deficiency can be silent. Patient 2 had GK deficiency and a severe phenotype involving psychomotor retardation and growth delay, bone dysplasia, and seizures, similar to the severe phenotype of one of the first described cases of GK deficiency. His younger brother, patient 3, also had GK deficiency, but so far his development has been normal. GK exon 17 was deleted in both brothers, implicating additional factors in causation of the severe phenotype of patient 2. Patient 4 had both GK deficiency with mental retardation and a GK missense mutation (D440V). Possible explanations for the phenotypic variation of these four patients include ascertainment bias; metabolic or environmental stress as a precipitating factor in revealing GK-related changes, as has previously been described in juvenile GK deficiency; and interactions with functional polymorphisms in other genes that alter the effect of GK deficiency on normal development.     

Analyses of muscular dystrophy and Con A deficiency traits in testcross progeny of chickens

Hereditary muscular dystrophic chickens of the Storrs strain possess two genetic disorders, muscular dystrophy (MD) and a deficient concanavalin A (Con A), a T-cell mitogen, mediated splenic lymphocyte blastogenic response. A possible amelioration of the MD phenotype in MD chickens expressing normal Con A was postulated on the basis of progeny segregating for these two traits in F2 genetic analyses. To test this possibility, testcross progeny were examined for segregation of MD and Con A deficiency traits, and for the degree of muscle destruction and Con A deficiency. The data show both traits to be inherited independently as autosomal recessive traits, and do not support any phenotypic modifications occurring in chickens expressing MD with normal Con A. In the testcross progeny, the Con A deficiency disorder is equally deficient in normal and MD progeny, and the degree of muscle destruction as measured by serum creatine phosphokinase levels is equally great in MD chickens with or without the Con A deficiency trait. The reduced numbers of MD chickens in the testcross progeny can be accounted for by chance and probably reflect losses during in ovo development.