Onset of transcription of the aminopeptidase N (leukemia antigen CD 13) gene at the crypt/villus transition zone during rabbit enterocyte differentiation

AbstractThe sequence of a cDNA clone (2.82 kbp) of rabbit intestinal aminopeptidase N (CD 13) is reported. Using the corresponding anti-sense RNA probe, the distribution of aminopeptidase N mRNA along the crypt/villus axis of the rabbit small intestine was studied by in situ hybridization. The aminopeptidase N gene is expressed along the whole length of the villus with a maximum at its base. Expression was not detected in the crypt cells. The distribution of aminopeptidase N mRNA correlates with the presence of active enzyme as monitored by histochemical staining. The results are compatible with onset of transcription of the aminopeptidase N gene at the crypt/villus transition zone during the enterocyte differentiation

Homotransplantation of the liver in a patientwith hepatoma and hereditary tyrosinemia

A girl with hereditary tyrosinemia, diagnosed at 6 months of age, was treated with a diet restricted inphenylalanine and tyrosine. At 91/2 years of age she developed an acutely enlarged liver and spleen, and the diagnosis of hepatocarcinoma was made. The patient received a liver transplant and tyrosine metabolites became normal while she was receiving a regular diet. Three months later, an infected thrombosis of the portal vein caused her death. Liver transplant appears to be an effective method of enzyme replacement in tyrosinemia and should be considered for prevention of hepatoma. © 1978 The C. V. Mosby Company

Epidermal growth factor-induced hydrolysis of phosphatidylcholine by phospholipase D and phospholipase C in human dermal fibroblasts

The enzymatic pathways for formation of 1,2-diradylglyceride in response to epidermal growth factor in human dermal fibroblasts have been investigated. 1,2-Diradylglyceride mass was elevated 2-fold within one minute of addition of EGF. Maximal accumulation (4-fold) occurred at 5 minutes. Since both diacyl and ether-linked diglyceride species occur naturally and may accumulate following agonist activation, we developed a novel method to determine separately the alterations in diacyl and ether-linked diglycerides following stimulation of fibroblasts with EGF. Utilizing this method, it was found that approximately 80% of the total cellular 1,2-diradylglyceride was diacyl, the remaining 20% being ether-linked. Addition of EGF caused accumulation of 1,2-diacylglyceride with out alteration in the level of ether-linked diglyceride. Thus, the observed induction of 1,2-diradylglyceride by EGF was due exclusively to increased formation of 1,2-diacylglyceride. In cells labelled with [ 3 H]choline, the water soluble phosphatidylcholine hydrolysis products, phosphorylcholine and choline, were increased 2-fold within 5 minutes of addition of EGF. No hydrolysis of phosphatidylethanolamine, phosphatidylserine, or phosphatidylinositol was observed. Quantitation by radiolabel and mass revealed equivalent elevations in phosphorylcholine and choline, suggesting stimulation of both phospholipase C and phospholipase D activities. To identify the presence of EGF-induced phospholipase D activity, cells were labelled with exogenous [ 3 H]1-0-hexadecyl, 2-acyl phosphatidylcholine and its conversion to phosphatidic acid in response to EGF determined. Radiolabelled phosphatidic acid was detectable in 15 seconds after addition of EGF and was maximal (3-fold) at 30 seconds. Consistent with the presence of EGF-induced phospholipase D activity, treatment of cells with EGF, in the presence of [ 14 C]ethanol, resulted in the rapid formation of [ 14 C]phosphatidylethanol, the product of phospholipase D-catalyzed transphosphatidylation. The formation of phosphatidylethanol, which competes for the formation of phosphatidic acid by phospholipase D, did not diminish the induction of 1,2-diglyceride by EGF. These data suggest that the phosphatidic acid formed by phospholipase D-catalyzed hydrolysis of phosphatidylcholine is not a major precursor of the observed increased 1,2-diglyceride. Thus, the induction of 1,2-diacylglycerol by EGF may occur primarily via phospholipase C-catalyzed hydrolysis of phosphatidylcholine.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49879/1/1041460216_ftp.pd

Regional distribution of some enzymes involved with putative neurotransmitters in the human visual system

Levels of protein and activity of several enzymes were determined in different portions of the visual system of the human brain. The enzymes studied were total cholinesterase (TChE), acetylcholinesterase (AChE), pseudocholinesterase (ChE), choline acetyltransferase (ChAc), monoamine oxidase (MAO), and N-methyltransferase (NMT). Brains of 17 patients were obtained at autopsy. The specimens were divided into 3 groups. One group consisted of the brains of subjects who were mentally normal prior to death. The second group of subjects had been diagnosed as chronic schizophrenics and the third had an organic brain syndrome. Each group included males and females. Subjects with an organic brain syndrome were significantly older than subjects in either of the other two groups. There were no significant differences in protein among the 3 groups for most of the visual areas. All enzyme activity was expressed per g of protein. TChE, AChE, and ChE activity varied markedly within the visual system, being usually lowest in the optic nerve and highest in the superior colliculus. There were no significant differences in TChE or AChE among the diagnostic groups. Unexpectedly, ChE was elevated in some brain areas in the chronic schizophrenic group. This finding needs further confirmation in a drug free group. ChAc did not differ significantly among the 3 diagnostic groups and, in general, was low throughout the visual system but highest in the superior colliculus and lateral geniculate. MAO activity was not significantly different among the 3 patient groups. Its activity in the gray matter was only slightly higher than in the white matter of the visual system. NMT activity was extremely low (about 0.1% the activity of the other enzymes) throughout all areas studied and did not differ significantly between areas or diagnostic groups.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33831/1/0000088.pd

The incorporation of14C‐glycerol into different species of diglycerides and triglycerides in rat liver slices

The relative rates of de novo synthesis of species of diglycerides and triglycerides from14C‐glycerol were examined in rat liver slices. Diglycerides containing one or two double bonds per molecule and triglycerides containing four or more double bonds per molecule represented 70% and 60% respectively of the newly synthesized diglycerides and triglycerides. The newly synthesized triglycerides were more unsaturated than the endogenous triglycerides. Our results suggest that a nonrandom synthesis of species of diglycerides occurred followed by an almost random utilization of the various diglyceride species for the biosynthesis of triglycerides.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142207/1/lipd0411.pd

Cholinergic mechanisms in the cat vestibular system

A neuropharmacological study was undertaken in the cat to obtain further evidence of the role of acetylcholine in vestibular function. It was shown that the vestibular nerve contains about half or less the enzymatic activity of choline acetyltransferase. acetylcholinesterase, cholinesterase and total cholinesterase than nucleus vestibularis lateralis (NVL).Field potentials as well as discharge of single neurones of nucleus vestibularis lateralis (NVL) were studied in locally anaesthetized, decamethonium immobilized ventilated cats before, during and after vestibular nerve and reticular formation stimulation. Various cholinergic agonists and antagonists and the adrenergic agonists -DOPA and (+)-amphetamine were then given intravenously to determine their effects. Three major evoked potentials to vestibular nerve stimulation were recorded in NVL. These potentials were labelled N1, N2and N3 on the basis of polarity and latency. Although the N1 and N3 waves were not much affected, the N3 wave was dramatically enhanced by physostigmine and reduced by scopolamine.About half of NVL neurones excited by vestibular nerve stimulation responded to muscarinic cholinergic drugs. Nucleus vestibularis lateralis responses to reticular formation (RF) stimulation were primarily nicotinic and were blocked by the nicotinic antagonist, mecamylamine, but not trimethadinium. Some neurones excited by RF stimulation were enhanced by -DOPA or (+)-amphetamine. The data indicate that cholinergic mechanisms are strongly involved in vestibular function. Adrenergic mechanisms are also involved, but to a much lesser extent.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22112/1/0000539.pd

A Combination of Nutriments Improves Mitochondrial Biogenesis and Function in Skeletal Muscle of Type 2 Diabetic Goto–Kakizaki Rats

BACKGROUND: Recent evidence indicates that insulin resistance in skeletal muscle may be related to reduce mitochondrial number and oxidation capacity. However, it is not known whether increasing mitochondrial number and function improves insulin resistance. In the present study, we investigated the effects of a combination of nutrients on insulin resistance and mitochondrial biogenesis/function in skeletal muscle of type 2 diabetic Goto-Kakizaki rats. METHODOLOGY/PRINCIPAL FINDINGS: We demonstrated that defect of glucose and lipid metabolism is associated with low mitochondrial content and reduced mitochondrial enzyme activity in skeletal muscle of the diabetic Goto-Kakizaki rats. The treatment of combination of R-alpha-lipoic acid, acetyl-L-carnitine, nicotinamide, and biotin effectively improved glucose tolerance, decreased the basal insulin secretion and the level of circulating free fatty acid (FFA), and prevented the reduction of mitochondrial biogenesis in skeletal muscle. The nutrients treatment also significantly increased mRNA levels of genes involved in lipid metabolism, including peroxisome proliferator-activated receptor-alpha (Ppar alpha), peroxisome proliferator-activated receptor-delta (Ppar delta), and carnitine palmitoyl transferase-1 (Mcpt-1) and activity of mitochondrial complex I and II in skeletal muscle. All of these effects of mitochondrial nutrients are comparable to that of the antidiabetic drug, pioglitazone. In addition, the treatment with nutrients, unlike pioglitazone, did not cause body weight gain. CONCLUSIONS/SIGNIFICANCE: These data suggest that a combination of mitochondrial targeting nutrients may improve skeletal mitochondrial dysfunction and exert hypoglycemic effects, without causing weight gain

Neurons Controlling Aplysia Feeding Inhibit Themselves by Continuous NO Production

Neural activity can be affected by nitric oxide (NO) produced by spiking neurons. Can neural activity also be affected by NO produced in neurons in the absence of spiking?Applying an NO scavenger to quiescent Aplysia buccal ganglia initiated fictive feeding, indicating that NO production at rest inhibits feeding. The inhibition is in part via effects on neurons B31/B32, neurons initiating food consumption. Applying NO scavengers or nitric oxide synthase (NOS) blockers to B31/B32 neurons cultured in isolation caused inactive neurons to depolarize and fire, indicating that B31/B32 produce NO tonically without action potentials, and tonic NO production contributes to the B31/B32 resting potentials. Guanylyl cyclase blockers also caused depolarization and firing, indicating that the cGMP second messenger cascade, presumably activated by the tonic presence of NO, contributes to the B31/B32 resting potential. Blocking NO while voltage-clamping revealed an inward leak current, indicating that NO prevents this current from depolarizing the neuron. Blocking nitrergic transmission had no effect on a number of other cultured, isolated neurons. However, treatment with NO blockers did excite cerebral ganglion neuron C-PR, a command-like neuron initiating food-finding behavior, both in situ, and when the neuron was cultured in isolation, indicating that this neuron also inhibits itself by producing NO at rest.Self-inhibitory, tonic NO production is a novel mechanism for the modulation of neural activity. Localization of this mechanism to critical neurons in different ganglia controlling different aspects of a behavior provides a mechanism by which a humeral signal affecting background NO production, such as the NO precursor L-arginine, could control multiple aspects of the behavior

The Aetiology of Diabetic Neuropathy: the Combined Roles of Metabolic and Vascular Defects

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75362/1/j.1464-5491.1995.tb00544.x.pd

The Complete Genome Sequence of the Pathogenic Intestinal Spirochete Brachyspira pilosicoli and Comparison with Other Brachyspira Genomes

Background: The anaerobic spirochete Brachyspira pilosicoli colonizes the large intestine of various species of birds and mammals, including humans. It causes ''intestinal spirochetosis'', a condition characterized by mild colitis, diarrhea and reduced growth. This study aimed to sequence and analyse the bacterial genome to investigate the genetic basis of its specialized ecology and virulence. Methodology/Principal Findings: The genome of B. pilosicoli 95/1000 was sequenced, assembled and compared with that of the pathogenic Brachyspira hyodysenteriae and a near-complete sequence of Brachyspira murdochii. The B. pilosicoli genome was circular, composed of 2,586,443 bp with a 27.9 mol% G+C content, and encoded 2,338 genes. The three Brachyspira species shared 1,087 genes and showed evidence of extensive genome rearrangements. Despite minor differences in predicted protein functional groups, the species had many similar features including core metabolic pathways. Genes distinguishing B. pilosicoli from B. hyodysenteriae included those for a previously undescribed bacteriophage that may be useful for genetic manipulation, for a glycine reductase complex allowing use of glycine whilst protecting from oxidative stress, and for aconitase and related enzymes in the incomplete TCA cycle, allowing glutamate synthesis and function of the cycle during oxidative stress. B. pilosicoli had substantially fewer methyl-accepting chemotaxis genes than B. hyodysenteriae and hence these species are likely to have different chemotactic responses that may help to explain their different host range and colonization sites. B. pilosicoli lacked the gene for a new putative hemolysin identified in B. hyodysenteriae WA1. Both B. pilosicoli and B. murdochii lacked the rfbBADC gene cluster found on the B. hyodysenteriae plasmid, and hence were predicted to have different lipooligosaccharide structures. Overall, B. pilosicoli 95/1000 had a variety of genes potentially contributing to virulence. Conclusions/Significance: The availability of the complete genome sequence of B. pilosicoli 95/1000 will facilitate functional genomics studies aimed at elucidating host-pathogen interactions and virulence