Neurotrophic regulation of insulin-sensitive amino acid uptake in rat fast muscle

Our object was to determine how innervation regulates muscle insulin sensitivity. Insulin-stimulated uptake of the nonmetabolized amino acid, 2-amino-isobutyric acid, was used as a measure of insulin sensitivity in denervated rat extensor digitorum longus muscles retaining either a similar 2.5-cm ("proximal denervation') or a similar to 0.5-cm ("distal denervation') length of distal nerve stump. Because both muscles were inactive in the first 24 h, any difference in insulin sensitivity could be due only to some trophic influence of the distal nerve stump. Fifteen hours after either type of denervation, 2-aminoisobutyric acid uptake was refractory to insulin. However, at 24 h, insulin sensitivity of distally denervated muscles (with or without a second ipsilateral proximal denervation) was normal, whereas that of proximally denervated muscles was still relatively insensitive. In the absence of insulin, the two types of denervated muscles at 24 h showed no difference in 2-aminoisobutyric acid uptake. Finally, organ culture of paired muscles with or without long nerve stumps showed corresponding differences in insulin-stimulated 2-aminoisobutyric acid uptake after 48 h in vitro. Thus, a neurotrophic factor, independent of impulse activity, stretch, or changes in blood flow, regulates one type of muscle insulin sensitivity.     

Effects of lithium deficiency in some insulin-sensitive tissues of diabetic Chinese hamsters

In this work, we report the effect of low-dose lithium carbonate on blood glucose levels and tissue lithium content in hereditary spontaneous diabetic Chinese hamsters (HSDCHs). Hepatic lithium levels are significantly lower in diabetic hamsters when compared to healthy controls: 2.05 +/- 0.26 and 3.04 +/- 0.11 micrograms/g, respectively. The same trend was observed in kidney and muscle: 18.26 +/- 0.24 vs 20.23 +/- 1.10 micrograms/g and 4.66 +/- 0.17 vs 5.95 +/- 0.67 micrograms/g, respectively. The significance level was p < 0.05 in all cases. Supplementation with lithium carbonate eliminated tissue lithium deficiency, and had a normalizing effect on blood glucose and glycosylated serum protein levels. The insulin sensitivity index (ISI) increased, thus reducing insulin resistance. Our results suggest that lithium deficiency in certain insulin-sensitive tissues may be associated with blood glucose imbalance resulting from insulin resistance.     

Trk neurotrophin receptor family immunoreactivity in rat and human pituitary tissues

Several lines of evidence suggest that neurotrophins may be involved in pituitary function. By immunocytochemical methods we analyzed the cellular distribution of their functional receptors in the pituitary gland. In the rat pituitary gland Trks were differentially distributed. Punctate immunoreactivity for TrkA was observed within the neural lobe, whereas numerous nerve endings were immunostained for TrkB and TrkC in the intermediate lobe. Endocrine cells of the intermediate lobe exhibited intense immunoreactivity for the three Trks, whereas scattered endocrine cells of the anterior lobe displayed a robust immunostaining for TrkC. In addition, TrkA and TrkB immunoreactivity was located in normal and neoplastic endocrine cells from human pituitary adenomas. The differential distribution of Trks in the hypophysis suggests a potential role of different neurotrophins in pituitary functions.     

Stimulation of asialoglycoprotein uptake by recombinant human hepatocyte growth factor in normal and damaged rat liver

BACKGROUND: Hepatocyte growth factor (HGF) is a strong mitogen of hepatocytes. However, little is known about the effect of HGF on the asialoglycoprotein receptors (ASGPR) of hepatocytes. The aim of this study was to identify alterations in binding of ligand to ASGPR by recombinant human HGF (rhHGF) infusion. METHODS: RhHGF was administered to rats with either normal or dimethylnitrosamine (DMN)-damaged livers. Technetium-99m-diethylenetriaminepentaacetic acid-galactosyl-human serum albumin (GSA) blood clearance was used to measure ASGPR activity. RESULTS: In normal and damaged rats, liver weight, hepatocyte nuclear size, and number of hepatocytes (cells/mm2) were not altered by rhHGF, but GSA blood clearance after rhHGF infusion was significantly increased over the preinfusion rate. CONCLUSIONS: Independent of proliferation of hepatocytes, rhHGF stimulates a hepatocytic function of the receptor-mediated uptake of ASGP.     

Role of platelet-activating factor in glucose uptake and utilization of different tissues

The particle transport characteristics of two ventilation configurations commonly used in hospital operating rooms (ORs), cross-flow and impinging-flow ventilation, were investigated. The computational fluid dynamics software FLUENT was used to simulate turbulent airflow with mixed convection in a three-dimensional, rectangular OR. Two OR personnel, a patient, OR spotlights, an anesthetics cart, and an operating table were represented in the room. Heat loads from the personnel, patient, and lights affected the airflow through buoyancy. Particles produced at the operation site with various sizes and initial conditions were tracked through the room. A stochastic model was used to include the random effects of turbulence on particle trajectories. Simulation results show that heat loads from the personnel, patient, and OR spotlights had an important effect on the airflow through natural convection. Particle trajectories were influenced greatly by the flow field structure, particle launch position, and turbulence in the flow, and somewhat by particle size. However, particle paths were insensitive to the launch velocity. Virtually identical trajectories were obtained for particles with launch velocities ranging from 0 to 1 m/sec in magnitude. Changes in ventilation configuration dramatically affected particle transport. The cross-flow ventilation configuration performed better, based on the criteria of removing particles from the breathing zone of room occupants. Proper flow field design and contaminant source placement can be used to control particle transport. Numerical simulations allow quick and inexpensive comparisons between room designs and provide details about airflow and contaminant transport.     

Replication of influenza virus in organ cultures of human and simian urogenital tissues and human foetal tissues

A survey of human adult tissues in organ cultures showed that influenza viruses (A/Moscow/1019/65 (h2n2) or a recombinant virus virulent for man (PR/8-A/England/939/69 Clone 7a(H3N2)) could infect uterus, bladder and conjunctiva but not oesophagus under the conditions employed; simian bladder and uterus were also susceptible. These results were similar to those already described for corresponding ferret tissues. Organ cultures of human foetal nasal mucosa, trachea, oesophagus, small and large intestine, and bladder consistently supported replication over 4 days or more with high virus yields. Lung, conjunctiva and umbilical cord were less consistently susceptible and gave lower yields. Placenta and kidney cultures allowed replication of virus in one of 8 and one of 4 experiments respectively, the yields being low and of short duration. Organ cultures of neural tissue (meninges and brain), lymphopoietic tissue (spleen, liver and thymus) and amnion did not support significant viral replication. The results are discussed in relation to possible infection of the foetus in utero with influenza virus.     

alpha-Ketoglutarate uptake in human fibroblasts

The effects of Corynebacterium parvum on host protection, tissue reaction and "in vivo" chemotaxis in Schistosoma mansoni infected mice were studied. The C. parvum was given intraperitoneally using a dose of 0.7 mg, twice a week (for 4 weeks), thirty days before (prophylactic treatment) or after infection (curative treatment). The host protection was evaluated through the recovery of adult worms by liver perfusion and was lower in the prophylactic group as compared to the control group (p = 0.018), resulting in 44% protection. The "in vivo" leukocyte response in both prophylactic and curative groups was higher as compared to the infected/non treated group (p = 0.009 and p = 0.003, respectively). Tissue reactions were described in the experimental and control groups, but there were not remarkable differences among them. The possible biological implications and relevance of the findings for the defensive response of the host and control of schistosomiasis are discussed.     

Distribution of catechol-O-methyltransferase enzyme in rat tissues

In the present study we show the distribution of catechol-O-methyltransferase (COMT) in various rat tissues with a highly specific antiserum prepared against recombinant rat COMT. Immunoprecipitation and immunocytochemical controls confirmed the COMT-specificity of the antibodies. The antiserum detected both the 24 KD soluble and the 28 KD membrane-bound forms of the enzyme. By immunohistochemical staining the COMT enzyme was found in most rat tissues. Staining was most intense in the liver and in the kidney, in agreement with previous studies and our immunoblotting results. In the gastrointestinal tract, epithelial cells of the stomach, duodenum, and ileum were immunoreactive for COMT. In pancreas, COMT immunoreactivity was found in insulin-producing beta-cells and somatostatin-producing D-cells but not in glucagon-producing alpha-cells of the islets of Langerhans. In pituitary, COMT immunoreactivity was found in cleft cells, in pituicytes of the posterior lobe, and in the anterior lobe, partly in the same cells containing luteinizing hormone (LH). In other endocrine organs, COMT immunoreactivity was found in epithelial cells of the thyroid gland and in zona glomerulosa of the adrenal cortex. In the brain, brightest immunofluorescence was seen in ependymal cells of the cerebral ventricles and choroid plexus. Weak to moderate immunofluorescence was found in the neuropil of several brain areas, including striatum and cortex. Scattered small neurons in spinal sensory ganglia were also COMT immunoreactive. Previous immunocytochemical studies, enzyme activity determinations, and distribution of the COMT mRNA are in general agreement with the results presented here. The wide distribution of COMT in different tissues suggests an important role for this protein in inactivation of catechol compounds.     

Common nuclear matrix proteins in rat tissues

Nuclear matrix proteins have been defined as insoluble residual proteins resulting from treatment of isolated nuclei with nucleases, detergents and high ionic strength buffers. They are considered as in part representing the proteins constituting the three-dimensional framework of the interphase nucleus. Though cell-specific nuclear matrix proteins have been differentiated from ubiquitously occurring (common) nuclear matrix proteins, the number and types of common nuclear matrix proteins have not yet been unequivocally established. In the present study nuclear matrix proteins were prepared from isolated nuclei of rat kidney, liver, lung, spleen and testes. The matrix proteins were separated by two-dimensional (2-D) electrophoresis and silver stained. Then the spot patterns were compared by computer-assisted image analysis. Composite images were derived for nuclear matrix proteins of individual tissues. Finding between 396-483 spots per tissue, a total of 964 individual spots were registered. Of these, 102 were common nuclear matrix proteins, as appearing in each of the tissue-characteristic images. The apparent molecular mass and pI data may serve for further identification of these nuclear proteins.     

Stop-flow studies of solute uptake in rat lungs

Stop-flow studies were used to characterize solute uptake in isolated rat lungs. These lungs were perfused at 8 or 34 ml/min for 10-28 s with solutions containing 125I-albumin and two or more of the following diffusible indicators: [3H]mannitol, [14C]urea, 3HOH, 201Tl+, or 86Rb+. After this loading period, flow was stopped for 10-300 s and then resumed to flush out the perfusate that remained in the pulmonary vasculature during the stop interval. Concentrations of 201Tl+ and 86Rb+ in the venous outflow decreased after the stop interval, indicating uptake from exchange vessels during the stop interval. The amount of these K+ analogs lost from the circulation during the stop interval was greater when the intervals were longer. However, losses of 201T1+ at 90 s approached those at 300 s. Because extraction continued after the vasculature had been flushed, vascular levels had presumably fallen to negligible levels during the stop interval. By 90 s of stop flow the vascular volume that was cleared of 201T1+ averaged 0.657 +/- 0.034 (SE) ml in the experiments perfused at 8 ml/min and 0.629 +/- 0.108 ml in those perfused at 34 ml/min. Increases in perfusate K+ decreased the cleared volumes of 201T1+ and 86Rb+. Uptake of [3H]mannitol, [14C]urea, and 3HOH during the stop intervals was observed only when the lungs were loaded at high flow for short intervals. Decreases in 201T1+ and 86Rb+ concentrations in the pulmonary outflow can be used to identify the fraction of the collected samples that were within exchange vessels of the lung during the stop interval and may help determine the distribution of solute and water exchange along the pulmonary vasculature.     

Kinetic analysis of cholesterol turnover in rat tissues

A number of studies have been conducted on serum cholesterol disappearance following a single injection of tracer. They have shown 2 or 3 component curves depending on the length of time of observation. They have been interpreted to indicate pools of cholesterol in fast or slow equilibrium with serum and generally depicted as representing groups of tissues. A cholesterol kinetic study was conducted using rats so that each tissue could be analyzed for appearance-disappearance of cholesterol from 30 minutes to 75 days. Serum and liver appeared to die-away for 30 days in a 2 component configuration, then exhibited a repetition of the same curve in the next 30 days. Skeletal muscle and kidney had a slow buildup for 2 weeks, then a plateau for 2 weeks then a 2 component die-away. Adipose showed a high plateau from 30 minutes to 30 days then a 2 component die-away, with specific activity higher than serum at all times. The data are interpreted to indicate that adipose tissue sequestered part of the tracer dose and all tissues reached equilibrium at about 30 days. After that time all tissues had a statistically significant 2 component die-away curve. The mathematical models tested suggest that in the steady state, cholesterol enters and exits the slow pool of serum, kidney, muscle and adipose and in liver enters both pools. Interpretation of the complete die-away is that the tracer dose first equilibrates with membrane free cholesterol, then with the intracellular cholesterol, and finally dies-away at the rate of release by the slow intercellular pool.     

Quantitation of water-soluble acylcarnitines and carnitine acyltransferases in rat tissues

The water-soluble acylcarnitines isolated from rat heart, skeletal muscle, liver, and testis have been characterized. The following acyl residues derived from the acylcarnitine fraction were found: acetyl, propionyl, isobutyryl, butyryl, alpha-methylbutyryl, isovaleryl, tiglyl, caproyl, beta-methylcrotonyl and methacrylyl. The amounts of these acylcarnitines in heart, liver, testis and skeletal muscle from fed rats were determined. Acetylcarnitine was the most abundant acylcarnitine; however, appreciable quantities of propionyl-, isobutyryl-, isovaleryl-, and tiglyl-carnitine were found. The levels of carnitine octanyltransferse, carnitine acetyltransferase and carnitine palmityltransferase activities were determined in several tissues. In addition, carnitine isovaleryltransferase and isobutyryltransferase activities were measured in heart, skeletal muscle, liver, testis and kidney. In all instances the specific activity of isobutyryltransferase was similar to the specific activity of acetyltransferase. The results are consistent with the proposal that carnitine is involved in the catabolism of branched-chain amino acids.     

Adenylate cyclase activity in human tissues

Adenylate cyclase activity in liver, lung, pancreas, and heart ventricle, from full-term and premature newborns has been assayed. Of all tissues studied, heart had the highest activity. Fluoride 10 mM stimulates adenylate cyclase in all tissues. Glucagon evoked a small activation of liver adenylate cyclase.     

Mammalian acetoacetate decarboxylase activity. Its distribution in subfractions of human albumin and occurrence in various tissues of the rat

In this article further information is presented about the characteristics of the mammalian enzyme acetoacetate decarboxylase (acetoacetate carboxylase, EC 4.1.1.4). The Michaelis-Menten plot shows a sigmoidal relationship between the enzyme activity (v) and the substrate concentration (s) indicating an allosteric hindrance. Because of this, the KM value can only be predicted to be equal to or less than 1 X 10(-1) M. Cysteine and glutathione, although activating the spontaneous decarboxylation, have no effect upon the enzyme activity. From experiments with human albumin by means of gel filtration with Sephadex G-200, it can be concluded that the acetoacetate decarboxylase activity does not depend upon the degree of polymerisation of albumin. From experiments performed by means of ion exchange chromatography the enzyme activity may be localized in the non-mercaptalbumin fraction. Investigation of enzyme activity in homogenates of various rat tissues, as well as in their respective subfractions, reveals that: (1) the specific activity of brain tissue exceeds those of liver and kidney and (2) most of the activity in liver tissue is localized in the 20 000 X g supernatant, containing the endoplasmatic reticulum, the ribosomes and the soluble part of the cytoplasm, while in brain tissue a high activity is found in the nuclei fraction.     

Methylsulfonyl metabolites of PCBs and DDE in human tissues

More than 15 years passed since bone marrow transplantation (BMT) have first introduced to the field of treatment of pediatric cancer. During this period, technology and modality of BMT have been improved steadily and several kinds of hemopoietic stem cell transplantation, for instance, allogeneic BMT from related or unrelated donor, unpurged or purged autologous BMT by 4-hydroperoxycyclophosphamide (4-HC) or magnetic immuno-beads, allogeneic or autologous peripheral blood stem cell transplantation and cord blood stem cell transplantation became available. Now we can choose the most suitable transplantation method for each patient from our repertory according to the patient's condition. In this article, treatment result of allogeneic BMT and 4-HC purged autologous BMT for children with acute leukemia and several kinds of hematopoietic stem cell transplantation for children with solid tumors in my hospital were reported.     

3H-Estradiol uptake and retention by target tissues of light-sterilized female rats

Tissue distribution of radioactivity was studied at 2, 4 and 6 h after intravenous injection of 3H-estradiol-17beta (41.7 ng/100 g b.w.) in 12 light-sterilized and 11 control female rats ovariectomized 72 h prior to injection. Female rats were light-sterilized by exposure to continuous illumination for 82 days and, based on the duration of continuous vaginal cornification and the absence of corpora lutea at post-mortem histological examination of the ovaries, were anovulatory for at least 30 days prior to injection. Control rats were housed under conditions similar to the experimentals except that they were exposed to alternating lighting (14 h light:10 h dark). They remained ovulatory throughout the experiment. Uterine 3H-estradiol uptake and retention were significantly depressed in the light-sterilized group. There were no significant differences in 3H-estradiol uptake or retention as a result of light-sterilization in any of the other tissues studied, including anterior, middle, and posterior hypothalamus, hippocampus, amygdala, cerebrum, anterior pituitary and plasma. The failure to detecta reduction in neural 3H-estradiol uptake demonstrates that the anovulatory state can exist without a concomitant reduction in the hypothalamic estrogen binding capacity. The possibility is discussed that the decreased target tissue binding noted in various types of anovulatory animals is the result, not the cause, of altered ovarian function.     

Mitochondrial mutational spectra in human cells and tissues

We have found that human organs such as colon, lung, and muscle, as well as their derived tumors, share nearly all mitochondrial hotspot point mutations. Seventeen hotspots, primarily G --> A and A --> G transitions, have been identified in the mitochondrial sequence of base pairs 10,030-10,130. Mutant fractions increase with the number of cell generations in a human B cell line, TK6, indicating that they are heritable changes. The mitochondrial point mutation rate appears to be more than two orders of magnitude higher than the nuclear point mutation rate in TK6 cells and in human tissues. The similarity of the hotspot sets in vivo and in vitro leads us to conclude that human mitochondrial point mutations in the sequence studied are primarily spontaneous in origin and arise either from DNA replication error or reactions of DNA with endogenous metabolites. The predominance of transition mutations and the high number of hotspots in this short sequence resembles spectra produced by DNA polymerases in vitro.     

Biopterin derivatives in human body fluids and tissues

Levels of biopterin derivatives in urine, serum, milk, cerebrospinal fluid, brain, and liver have been measured with the Crithidia fasciculata assay. Normal levels in serum and urine have been given and compared with those in a number of benign and malignant proliferative disorders, phenylketonuria, kidney disease, Parkinson's disease, schizophrenia, controlled epilepsy, rheumatoid arthritis, and pernicious anaemia. The active component of Crithidia factor in serum was 7,8-dihydrobiopterin. Tissue, urine, and some serum samples contained two active materials, the principal one being 7,8-dihydrobiopterin; a minor constituent was probably tetrahydrobiopterin. Serum biopterin levels following methotrexate administration were raised and subsequent administration of folic acid and 5-formyltetrahydrofolic acid further increased serum levels of biopterin derivatives; this was in contrast to the total absence of response to oral folates without prior methotrexate and to 5-methyltetrahydrofolic acid either with or without methotrexate being given.