Carnitine status and blood ammonium levels in low birth weight infants

Forty-three low birth weight infants appropriate for gestational age (AGA) were monitored to evaluate carnitine status in relation to blood ammonium levels. The infants were grouped into three depending on blood ammonium level on postnatal day 7: 62.9 +/- 3.8 mumol/L in group 1 (N = 13), 38.9 +/- 8.4 mumol/L in group 2 (N = 23), and 24.5 +/- 2.9 mumol/L in group 3 (N = 9). Plasma free carnitine levels decreased in all three groups (p less than 0.001) and plasma short chain acylcarnitine increased only in group 1 (p less than 0.002), compared to findings in normal infants. The blood ammonium level positively and negatively correlated to plasma short chain acylcarnitine (p less than 0.002) and plasma free carnitine levels (p less than 0.002), respectively. The reabsorption rate of free carnitine in renal tubules (RRFC) was decreased at rates of 37.5, 27.5, and 25% of infants in groups 1, 2, and 3, respectively. The acylcarnitine/free carnitine clearance ratio (RAFCC) was decreased in groups 1 (p less than 0.01) and 2 (p less than 0.05) compared with group 3. Thus, an accumulation of short chain acyl moieties and insufficiency in renal absorption of free carnitine are putative causes of lowered plasma free carnitine in infants with higher blood levels of ammonium. The possibility that the carnitine status regulates blood ammonium levels in low birth weight infants warrants continued investigation.

Structure of the ornithine transcarbamylase (OTC) gene and DNA diagnosis of OTC deficiency

Complementary and genomic DNA clones corresponding to human ornithine transcarbamylase (OTC) have been isolated and analyzed. Restriction fragment length polymorphisms (RFCPs) on OTC gene locus were analyzed in Japanese female population. Based on these data, a prenatal diagnosis of OTC deficiency was carried out in a risk family. A C-to-T substitution was found in exon 5 of OTC gene is an another female patient.

Protective effect of lipoproteins containing apoprotein A-I on Cu2+-catalyzed oxidation of human low density lipoprotein

Two apoprotein A-I (apoA-I)-containing lipoproteins, one containing apoA-I and apoA-II (LpA-I/A-II) and the other containing only apoA-I (LpA-I), were examined for their effect on Cu2+-mediated oxidation of low density lipoprotein (LDL). The presence of LpA-I or LpA-I/A-II prevented LDL oxidation when assessed by the electrophoretic mobility, apoprotein B fragmentation and amounts of thiobarbituric acid-reactive substances. The protection of LDL oxidation by these lipoproteins was effective for up to 6 h, with LpA-I being more active than LpA-I/A-II. Results from these in vitro model experiments raise a possibility that LpA-I may play a role in protecting LDL from Cu2+-mediated oxidation.

Physiologic and metabolic aspects of anticonvulsants

A great number of anticonvulsants are available for treating these different types of epilepsy. Therapeutic drug monitoring has been favored as the method for controlling drug concentrations in the plasma and preventing untoward effects. When these anticonvulsants are prescribed to treat epilepsy in children, careful monitoring is most important because drug metabolism varies depending on maturation and development of body functions. Molecular approaches are also important to elucidate the effectiveness of the drugs for treatment of different seizure disorders and should contribute to a better understanding of body functions.

Quantitative and qualitative changes of apolipoprotein AI-containing lipoproteins in patients on continuous ambulatory peritoneal dialysis

Using immunoaffinity chromatography, two species of apo-AI containing lipoproteins (AILp); lipoprotein containing apo-AI and apo-AII (Lp-AI/AII), and lipoprotein containing apo-AI, but no apo-AII (Lp-AI) were isolated from 13 female patients on continuous ambulatory peritoneal dialysis (CAPD), then characterized. The results were compared with findings obtained in agematched normolipidemic (control I) and mild hypertriglyceridemic (control II) female subjects. In comparison with control I: In AILp, the levels of total cholesterol (TC), cholesteryl ester (CE) and phospholipid (PL), and the levels of apoE were significantly lower in the CAPD patients while the levels of triglyceride (TG) and apo-CIII were significantly higher in these patients. The levels of apo-AI and apo-AII did not differ between the CAPD and control subjects. In Lp-AI/AII, changes of TC, CE, PL, TG, and apolipoproteins were similar to those of AILp, except for the ratio of apo-AI/apo-AII and the level of apo-CII, which was higher in the CAPD patients. In Lp-AI, changes of TC, CE, PL, and TG were also similar to those of AILp and Lp-AI/AII, but the apo-AI level was significantly lower in the CAPD patients. In comparison with control II: In AILp, the levels of PL, apo-AI, apo-AII, and apo-E were significantly lower in CAPD patients, but the apo-CIII levels were significantly higher. In Lp-AI/AII, the levels of PL and apo-E were significantly lower in CAPD patients.(ABSTRACT TRUNCATED AT 250 WORDS)

A SPECT study in internal carotid artery occlusion: discrepancies between flow image and neurologic deficits

A SPECT (single photon emission computed tomography) study in internal carotid artery (ICA) occlusion was performed in 6 patients. The validity of iodoamphetamine (IMP) SPECT study in the evaluation of cerebral blood flow (CBF) or neurologic function is still controversial. In this study, the authors showed several cases in whom SPECT images of brain were not compatible with their neurologic deficits. In 2 typical cases, a large low-density area was observed in the non-dominant hemisphere in computed tomography (CT) scan, but no apparent motor-sensory deficits in left limbs were present. In these patients, SPECT study also revealed flow reduction in the affected side of the brain. So there was a possibility that an IMP brain image could not always reflect CBF, which maintains neurologic function of the brain.

Pathological findings of two types of lymphoid malignancy in sheep inoculated with bovine leukemia virus

Different types of lymphoid malignancy were observed in two sheep inoculated with BLV-containing materials. Sheep 1 showed severe leukemic change in the peripheral blood and splenomegaly but lymphosarcoma in the lymph nodes was absent. Sheep 2 had lymphosarcoma in the lymph nodes and various organs. Neoplastic cells had B-cell marker in both cases and a few neoplastic cells contained intracytoplasmic IgM in sheep 2. It was presumed that B-cells might be transformed into neoplastic cells on the way of their differentiation. Some of neoplastic cells might have ability of immunoglobulin-production in sheep 2.

Ornithine transcarbamylase deficiency resulting from a C-to-T substitution in exon 5 of the ornithine transcarbamylase gene

To define the molecular basis for the TaqI site alteration in the ornithine transcarbamylase (OTC) (E.C.2.1.3.3) gene of a female patient with mild OTC deficiency, we used a combination of genomic amplification followed by direct sequencing and oligodeoxyribonucleotide hybridization. We obtained evidence for a C-to-T substitution in exon 5 (codon 141) of this gene. This mutation generates a stop codon, in place of Arg, at amino acid 109 of the mature OTC protein. The mutation arose, de novo, in a germ cell of one of the parents.

Relationship of milk intake and vitamin K supplementation to vitamin K status in newborns

Vitamin K status was evaluated by measuring blood acarboxyprothrombin (PIVKA-II) levels on the fifth day of life. The incidence of PIVKA-II-positive infants was higher in breast-fed babies than in those given supplementary (mixed) feeding. The median of total amount of milk intake during the first 3 days was significantly lower in PIVKA-II-positive infants than in PIVKA-II-negative infants among infants given both types of feedings. In addition, there was a significant negative correlation between a positive PIVKA-II proportion and the amount of milk intake in the breast-fed babies. The minimum dose of vitamin K2 necessary to prevent a positive PIVKA-II reading was 15 micrograms among babies with a normal absorption potential.

Complete primary structure of the transacylase (E2b) subunit of the human branched chain alpha-keto acid dehydrogenase complex

We isolated from a placental cDNA library by immunoscreening a cDNA clone encoding the transacylase (E2b) precursor of the human branched chain alpha-keto acid dehydrogenase (BCKDH) complex. The cDNA insert consists of 2,649 base pairs with an open reading frame of 1,431 base pairs which can be translated into 477 amino acids and a 3'-untranslated region of 1,205 base pairs. The deduced amino acid sequence includes a leader peptide of 56 amino acid residues, a lipoyl-bearing domain, a E3-binding domain and an inner core domain. A mature human E2b subunit is likely to contain 421 amino acid residues with a calculated Mr 46,322. The nucleotide sequence of the open reading frame and the deduced amino acid sequence of the human E2b shows 91.6% and 92.0% homology with those of the bovine E2b subunit, respectively.

Primary structure and gene localization of human prolidase

Complementary DNA clones of prolidase (imidodipeptidase, EC 3.4.13.9) were isolated from human liver and placental cDNA libraries. Two clones named lambda PL21 and lambda PP6 from the liver and placental cDNA libraries, respectively, were analyzed in detail. The first clone, lambda PL21, carried a cDNA insert of 1.7 kilobase pairs and covered all the coding region of human prolidase mRNA. The second clone, lambda PP6, contained a 1.8-kilobase insert with a full-length 3'-untranslated region. Comparison of the amino acid sequence predicted from the nucleotide sequence of the cDNA insert of the two clones with the partial amino acid sequence determined by Edman degradation of peptides derived from human erythrocyte prolidase established that both clones code for human prolidase. The amino terminus of the human mature enzyme is blocked and seems to begin with the sequence X-Ala-Ala-Ala. Presumably no processing occurs at the carboxyl terminus. The mature enzyme is composed of 492 residues, corresponding to Mr 54,305. The sequence of prolidase is unique and not similar to any known protein, except for a significant similarity to regions of F1-ATPase alpha and beta subunits from various sources. The gene has been mapped to the short arm of chromosome 19 (19p13.2). Elucidation of the complete amino acid sequence and the gene location of prolidase should provide the basis for understanding structure-function relationships and also inherited disorders caused by deficiency of this metabolically important enzyme.

[An usage of cultured human cell lines in studies of inherited metabolic disease]

Cultured skin fibroblasts and lymphoblastoid lines (established by Epstein-Barr infection) derived from patients have been commonly used in studies on inherited metabolic disorders. It is generally accepted that, on some occasions, valuable information for comprehending the normal transport function and intracellular metabolism in human cells only becomes available through studies using affected cells, and not normal cells. Besides clarification of the mechanism an abnormal function caused by a mutant enzyme, cultured cells provide other useful information (or products), with advanced procedures including cell fusion and gene technology; genetic heterogeneity (gene complementation analysis), correction of mutant genes (transfer of genes or gene products), gene cloning of a specific locus (using chromosomal deletion) and gene expression. The application of "reverse genetics" may permit further access to a complex cellular system.

A new technique of identifying the epidural space "dripping infusion method"

We developed a new visual technique o identifying the epidural space, using the hydrostatic pressure produced by a suspended micro-drip intravenous apparatus. When the needle pierces the ligamentum flavum, the resistance to positive pressure disappears and the saline in the apparatus flows freely into the epidural space. Thus, the entry of the needle point into the epidural space is visually confirmed by the appearance of dripping flow in the drip bulb (dripping infusion sign). This procedure was clinically evaluated at the thoraco-cervical area in 114 patients; the thoracic area in 116; and the lumbar area in 272, respectively. In 491 (97.8%) of the patients, the epidural space was identified with facility. In the remaining 11 patients (2.2%), a false dripping infusion sign appeared at the more superficial site than expected. If the pressure waveform in the epidural space is analyzed, the correct positioning of the needle can be easily confirmed. We believe that this method is one of the most accurate visual methods of identifying the epidural space and useful for teaching the epidural blockade to students and residents.

Development and serial passage of persistent lymphocytosis associated with bovine leukemia virus infection in cattle

Two calves each were inoculated with 1.5 x 10(8) or 5 x 10(9) lymphocytes collected from each one cow which had persistent lymphocytosis (PL) and antibodies to bovine leukemia virus (BLV). A sudden increase in the number of peripheral blood lymphocytes (PBL) was observed 14 and 23 days, respectively, after inoculation and the maximum number reached 29,000 and 52,000/microliters 72 and 57 days after inoculation. Although the degree of PL decreased gradually in these cattle, it continued until 14 and 44 months after inoculation when one animal was sacrificed and the other died of lymphosarcoma. The PL was passaged in cattle by inoculation of a large number of PBL obtained from cattle at the stage of PL (PLL). The degree of PL was severer in cattle inoculated with a larger number of PLL. PL was not caused by inoculation of PBL obtained from either BLV-infected non-PL cattle or cattle free of BLV. The PL was also caused by inoculation of PLL into BLV-infected non-PL cattle. On the other hand, it was not observed after inoculation of a large amount of cell-free virus obtained from short-term cultures of PLL. Antibodies to BLV developed earlier and to higher levels in cattle inoculated with PLL than in those inoculated with cell-free virus. These facts show that infection with BLV was established more effectively by PLL than by cell-free virus, the infection may occur by lymphocyte to lymphocyte interaction and the actual number of infected BLV may have an important role in development of PL.

Normal sonographic findings of the infant temporal lobe in coronal sections

Coronal sonograms of the temporal lobe of the infant brain were obtained using a real time sector scanner with a 5.0 MHz transducer probe. The precise normal anatomy in the coronal sections was determined by correlating with corresponding brain specimens. It was revealed that the spatial arrangement of structures in the medial part of the temporal lobe, i.e. the hippocampal formation and the inferior horn, varied in the three different planes. In the plane through the anterior part of the temporal lobe, these structures were seen as a horizontal lamellar configuration, whereas in the plane through the middle part these structures were depicted as a typical interfolded arrangement. However, the hippocampal formation was barely visible in the plane through the posterior part.

Age- and sex-related differences in lipoproteins containing apoprotein A-I

We investigated age- and sex-related differences in the structure and composition of two species of lipoproteins that contain apoprotein (apo) A-I (A-I Lp): lipoproteins containing apo A-I and apo A-II (Lp A-I/A-II), and lipoprotein containing apo A-I but no apo A-II (Lp A-I), which were isolated by immunoaffinity chromatography. Sixty normolipidemic volunteers were assigned to one of three groups based on their ages and sexual maturation (Group A, prepubertal; Group B, puberty; and Group C, postpuberty). In A-I Lp, the levels of total cholesterol, cholesteryl ester, phospholipid, and apo A-I were lower in males during puberty and then remained stable. In Lp A-I/A-II, there were no age- or sex-related changes in lipids or in apo A-II. Levels of apo A-I in the females were lower with advance in age, although significant differences were observed only between pre- and postpubertal subjects. In Lp A-I, the levels of total cholesterol, cholesteryl ester, phospholipid, and apo A-I were lower in males during puberty and remained stable thereafter, as in the case of A-I Lp. Therefore, the age- and sex-related differences observed in A-I Lp appear to be primarily due to the differences in Lp A-I. When we take into account the constancy of Lp A-I/A-II levels in all groups, the physiological function of A-I Lp (high density lipoprotein) in each individual may be limited by the Lp A-I levels.

Biochemical nature of pyruvate dehydrogenase complex in the patient with primary lactic acidaemia

The biochemical nature of the pyruvate dehydrogenase complex (PDHC) in muscle was studied in a patient with pyruvate dehydrogenase complex deficiency. The enzyme activity was approximately 30% of the control level and the apparent Km value of the enzyme was similar to the control value. The immunoblot pattern of each subunit protein, E1 alpha, E1 beta, the component X, E2 and E3, was comparable to that of the control on both one- and two-dimensional electrophoresis, the staining of each subunit protein being reduced in intensity, corresponding to the reduced enzyme activity. The enzyme deficiency is likely to be quantitative rather than qualitative, although the actual mechanism is unknown.

Mutation of the E1 alpha subunit of the pyruvate dehydrogenase complex, in relation to heterogeneity

Pyruvate dehydrogenase complex was studied using bio- and immunochemical methods in cultured cells derived from two patients with the severe type and one patient with the mild type of pyruvate dehydrogenase complex deficiency. In patients 1 and 2, enzyme activity was all but undetectable and associated with the absence of E1 alpha subunit of the complex. Patient 3 had a slightly reduced level of enzyme activity, and this was associated with a larger form of E1 alpha subunit. The amount and size of E1 alpha mRNA in the three patients was similar to that of control samples. Thus, the severity of E1 alpha deficiency in these three patients is likely to depend on the type of mutation in the pyruvate dehydrogenase E1 alpha subunit and the synthesis and degradation rate of the subunit.

Structure of the rat argininosuccinate lyase gene: close similarity to chicken delta-crystallin genes

Argininosuccinate lyase (EC 4.3.2.1) is an enzyme of arginine biosynthesis and is also involved in the urea cycle in the liver of ureotelic animals. A comparison of cDNA-derived amino acid sequences revealed that argininosuccinate lyase is highly homologous with chicken delta-crystallin, a major structural protein of the eye lens. The gene for the rat argininosuccinate lyase was cloned and its structure was determined. This gene is a single-copy gene about 14 kilobases long and is split into 16 exons. A comparison with chicken delta-crystallin genes revealed that all introns interrupt the protein-coding regions at homologous positions. This close similarity in structural organization provides strong evidence for the view of Piatigorsky et al. [Piatigorsky, J., O'Brien, W. E., Norman, B. L., Kalmuck, K., Wistow, G., Borras, T., Nickerson, J. M. & Wawrousek, E. F. (1988) Proc. Natl. Acad. Sci. USA 85, 3479-3483] that chicken delta 1- and delta 2-crystallin genes evolved by recruitment and duplication of the preexisting argininosuccinate lyase gene and that delta 2-crystallin is probably the direct homologue argininosuccinate lyase.