BACKGROUND: Low-dose cyclosporine (CsA)/mycophenolate mofetil (MMF) therapy has significantly reduced the frequency of rejection and drug-induced side effects in rat hindlimb allograft recipients. With an eye toward direct clinical application, we developed a large-animal extremity composite tissue allograft model to assess the antirejection efficacy and systemic toxicity of combination CsA/MMF treatment. METHODS: Radial forelimb osteomyocutaneous flap transplants were performed between size-matched, outbred pigs assigned to one of two groups: 5 control pigs received no immunosuppression, and 10 pigs received a once-daily oral CsA/MMF/prednisone regimen. Rejection was assessed by visual inspection of flap skin and correlated with serial histopathologic examination of skin biopsies. RESULTS: In all control pigs, the flap was completely rejected on day 7. Of the 10 pigs receiving treatment, one died from pneumonia and an another from an anesthetic complication on days 19 and 30, respectively, without signs of rejection. Two flaps were lost on days 25 and 29 from severe rejection. Three pigs were free of rejection at the end of the 90-day follow-up period, and three had stable mild-to-moderate rejection at 90 days (P= 0.0007 vs. controls). White blood cell and platelet counts, serum creatinine values, and liver function tests remained normal in all animals receiving immunosuppressive therapy. CONCLUSIONS: Our results, to our knowledge, demonstrate for the first time that rejection can be significantly delayed in a large-animal composite tissue allograft model including skin using only orally administered agents dosed according to clinically relevant strategies without significant drug-specific systemic side effects.

Animals↗

PubMed1998

Is absence of pyruvate dehydrogenase complex in mitochondria a possible explanation of significant aerobic glycolysis by normal human leukocytes?

The oxygen consumption of leukocyte mitochondria of both healthy donors and leukemic patients was tested by using different respiratory substrates. The results indicate that pyruvate could not be utilized by mitochondria of normal leukocytes, whereas mitochondria of leukemic leukocytes could use pyruvate as a good respiratory substrate. A search for the possible presence of pyruvate dehydrogenase complex (PDC) in leukocytes indicates that this enzyme is apparently absent in mitochondria of normal leukocytes but is quite active in mitochondria of leukemic leukocytes. The absence of PDC in normal leukocyte mitochondria can explain the phenomenon of significant aerobic glycolysis that has been observed in normal leukocytes.

Acetyl Coenzyme A↗

PubMed1998

Bactericidal/permeability-increasing protein for severe meningococcal sepsis.

Explore the source record for details and available documents.

Anti-Infective Agents↗

PubMed1998

Xylose transport by the anaerobic thermophile thermoanaerobacter ethanolicus and the characterization of a D-xylose-binding protein

Thermoanaerobacter ethanolicus is a xylose-utilizing thermophilic anaerobe that produces considerable amounts of ethanol. A protein in xylose-growing cells was solubilized from cell membranes by extraction with octyl-beta-glucoside. Internal peptide sequencing revealed that the protein was the product of a gene, xylF, encoding a putative D-xylose-binding protein. Metabolic labeling with 14C palmitic acid suggested that this is a lipoprotein that is anchored to the cell membrane via a cysteine residue. Binding was highly specific for xylose as evident by the lack of competition by sugars with structures similar to xylose. The apparent Kd of the protein for xylose was approximately 1.5 &mgr;M, and this value was very similar to the affinity constant determined for xylose transport by whole cells at low substrate concentrations. Uptake experiments with cells also suggested the presence of a separate low-affinity system. Binding activity varied less than 20% over a pH range of 4-8, and the level of activity was virtually unaffected when temperature was varied between 40 degreesC and 80 degreesC. This is the first biochemical characterization of a D-xylose-binding protein from a thermophilic organism.

Journal Article↗

PubMed1998

Increased incidence of congenital malformations in children with transient thyroid-stimulating hormone elevation on neonatal screening.

We investigated the incidence of congenital malformation in all infants with raised thyroid-stimulating hormone (TSH) levels on neonatal screening in Scotland between August 1979 and December 1993. Of 344 infants with elevated TSH, 31 (9%) had one or more malformations: 12 cardiac 15 noncardiac, and 16 dysmorphic syndromes (including 5 with Down syndrome). Criteria were devised to distinguish between definite or probable congenital hypothyroidism and transient TSH elevation. Congenital hypothyroidism was considered definite in 224 (65.1%) infants and probable in 11 (3.2%). Eighty-eight (25.6%) infants had transient TSH elevation, whereas thyroid status was uncertain in 21 (6.1%). In the definite group 12 (5.4%) infants had one or more malformations compared with 13 (14.8%) in the transient group. Cardiac malformation, noncardiac malformation, dysmorphic syndromes, and "sickness" were much more frequent in the transient compared with the definite group: 5.7% versus 1.8%, 8.0% versus 1.8%, 6.8% versus 2.7%, and 37.5% versus 7.1%, respectively. The incidence of congenital malformation in bonafide congenital hypothyroidism is lower than has been previously reported. The high incidence of congenital malformation associated with transient TSH elevation indicates the need to reevaluate the diagnosis of hypothyroidism in all infants with TSH elevation and concurrent illness or malformation.

Case-Control Studies↗

PubMed1998

Comparison between two different modes of oxygen therapy during immediate postoperative period following mitral commisurotomy.

Hypoxaemia is a common postoperative problem after thoracotomy. Oxygen therapy with continuous monitoring by pulse oximetry should be a routine practice. This study was conducted to compare the efficacy between nasal cannula and ventimask for post-thoracotomy oxygen supplementation on 20 patients divided into 2 groups of 10 each undergoing closed mitral commisurotomy. The study period was of 5 months duration from March to July, 1996. The mean oxygen saturation remained above 98% in both the groups receiving oxygen either by nasal cannula or ventimask. As there was adequate oxygenation, the cost benefit ratio favours the use of nasal cannula for routine postoperative oxygen supplementation in the closed mitral commisurotomy patients.

Adolescent↗

PubMed1998

Plasma zinc status in Indian childhood tuberculosis: impact of antituberculosis therapy.

SETTING: Department of Paediatrics and Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh, India. OBJECTIVE: To assess the plasma zinc status in children with tuberculosis and to correlate it with nutritional status, activity and severity of disease in relation to antituberculosis therapy. DESIGN: The plasma zinc status of 50 children with different forms of tuberculosis was compared with 10 healthy and 10 malnourished children without tuberculosis at 0, 1, 2, 3 and 6 months of antituberculosis therapy. RESULT: The mean plasma zinc concentration in children with pulmonary tuberculosis (n = 20) was 68.65+/-2.50 microg/dl, central nervous system (CNS) tuberculosis (n = 10) was 64.20+/-3.82 microg/dl, tuberculous lymphadenitis (n = 10) was 63.2+/-3.77 microg/dl and disseminated tuberculosis (n = 10) was 59.0+/-2.75 microg/dl at 0 months. The mean plasma zinc level of healthy children was 129.10+/-3.01 microg/dl and in malnourished non-tuberculous children it was 108.40+/-3.16 microg/dl. Thus children with tuberculosis had significantly lower plasma zinc level than those without tuberculosis, irrespective of their nutritional status (P < 0.001). There was a significant rise in zinc level at the end of 6 months of antituberculosis therapy (P < 0.001). CONCLUSION: Plasma zinc status may prove to be a good objective marker for monitoring the severity of the disease and the response to therapy.

Antitubercular Agents↗

PubMed1997

Selective inhibition of mitochondrial respiration and glycolysis in human leukaemic leucocytes by methylglyoxal.

The effect of methylglyoxal on the oxygen consumption of mitochondria of both normal and leukaemic leucocytes was tested by using different respiratory substrates and complex specific artificial electron donors and inhibitors. The results indicate that methylglyoxal strongly inhibits mitochondrial respiration in leukaemic leucocytes, whereas, at a much higher concentration, methylglyoxal fails to inhibit mitochondrial respiration in normal leucocytes. Methylglyoxal strongly inhibits ADP-stimulated alpha-oxoglutarate and malate plus NAD+-dependent respiration, whereas, at a higher concentration, methylglyoxal fails to inhibit succinate and alpha-glycerophosphate-dependent respiration. Methylglyoxal also fails to inhibit respiration which is initiated by duroquinone and cannot inhibit oxygen consumption when the N,N,N', N'-tetramethyl-p-phenylenediamine by-pass is used. NADH oxidation by sub-mitochondrial particles of leukaemic leucocytes is also inhibited by methylglyoxal. Lactaldehyde, a catabolite of methylglyoxal, can exert a protective effect on the inhibition of leukaemic leucocyte mitochondrial respiration by methylglyoxal. Methylglyoxal also inhibits l-lactic acid formation by intact leukaemic leucocytes and critically reduces the ATP level of these cells, whereas methylglyoxal has no effect on normal leucocytes. We conclude that methylglyoxal inhibits glycolysis and the electron flow through mitochondrial complex I of leukaemic leucocytes. This is strikingly similar to our previous studies on mitochondrial respiration, glycolysis and ATP levels in Ehrlich ascites carcinoma cells [Ray, Dutta, Halder and Ray (1994) Biochem. J. 303, 69-72; Halder, Ray and Ray (1993) Int. J. Cancer 54, 443-449], which strongly suggests that the inhibition of electron flow through complex I of the mitochondrial respiratory chain and inhibition of glycolysis by methylglyoxal may be common characteristics of all malignant cells.

Adenosine Triphosphate↗

PubMed1997

Agonist-induced morphologic decrease in cellular D1A dopamine receptor staining.

The distribution of D1A dopamine (DA) receptor proteins was assessed by using subtype specific antireceptor antisera after acute DA exposure. The immunofluorescent staining of D1A DA receptor protein expression was examined in (1) stably transfected Chinese hamster ovary (CHO) cells, (2) primary striatal cell cultures, and (3) rat striatal brain slices. After agonist exposure as brief as 2 min and as long as 60 min, profound loss of immunofluorescent D1A receptor protein staining occurred in each paradigm. Additionally in the tissue slice, immunofluorescent neuropil staining for the receptor protein also was attenuated. The DA-induced alteration in receptor protein staining was blocked by the antagonist (+)-butaclamol and by the selective D1-family antagonist SCH 23390. Receptor staining patterns reverted back to the control immunofluorescent distribution within 15 min after removing the agonist from the bath. Immunofluorescence for the second-messenger cyclic AMP increased at all DA exposure times in the three experimental paradigms, was blocked by D1-family antagonists, and decreased to basal staining after brief recovery periods. This demonstrated the functional integrity of the D1A receptor in target cells. Pretreatment with the mitogenic plant lectin concanavalin A blocked the immunofluorescent decrease in receptor staining but not the elevation of the second messenger, indicating a morphologic distinction in these two events, parallel to other biochemical reports. The data suggested that a morphologic basis of acute homologous D1A DA receptor desensitization may be transposition of membrane-surface receptors to a transiently unavailable, intracellular compartment. This finding is supported by specific fluorescence incorporation of FM1-43, used as a marker of endocytosis, in CHO cells treated with DA.

Animals↗

PubMed1997

Does excessive adenosine 5'-triphosphate formation in cells lead to malignancy? A hypothesis on cancer.

In biological systems, adenosine triphosphate (ATP) is the principal contributor of free energy necessary for anabolic reactions and is also a precursor of nucleic acids. Moreover, active transport of metabolites into cells is also driven by hydrolysis of ATP. So, a cell may grow, multiply and ultimately turn malignant when it has been transformed in such a manner that it produces excess ATP as compared with its usual metabolic demand. Recent studies have indicated that mitochondrial complex I and the glycolytic enzyme glyceraldehyde 3-phosphate dehydrogenase (GA3PD) may be critically altered specifically in malignant cells. So, we further propose that this excessive ATP formation may be due to altered mitochondrial complex I and GA3PD of malignant cells.

Adenosine Triphosphate↗

PubMed1997

Inactivation of glyceraldehyde-3-phosphate dehydrogenase of human malignant cells by methylglyoxal.

The effect of methylglyoxal on the activity of glyceraldehyde-3-phosphate dehydrogenase (GA3PD) of several normal human tissues and benign and malignant tumors has been tested. Methylglyoxal inactivated GA3PD of all the malignant cells (47 samples) and the degree of inactivation was in the range of 25-90%, but it had no inhibitory effect on this enzyme from several normal cells (24 samples) and benign tumors (13 samples). When the effect of methylglyoxal on other two dehydrogenases namely glucose 6-phosphate dehydrogenase (G6PD) and L-lactic dehydrogenase (LDH) of similar cells was tested as controls it has been observed that methylglyoxal has some inactivating effect on G6PD of all the normal, benign and malignant samples tested, whereas, LDH remained completely unaffected. These studies indicate that the inactivating effect of methylglyoxal on GA3PD specifically of the malignant cells may be a common feature of all the malignant cells, and this phenomenon can be used as a simple and rapid device for the detection of malignancy.

Carcinoma, Squamous Cell↗

PubMed1997

Similar nature of inhibition of mitochondrial respiration of heart tissue and malignant cells by methylglyoxal. A vital clue to understand the biochemical basis of malignancy.

The effect of methylglyoxal on the oxygen consumption of mitochondria of heart and of several other organs of normal animals of different species has been tested. The results indicate that methylglyoxal (3.5 mM) strongly inhibits ADP-stimulated alpha-oxoglutarate and malate plus pyruvate-dependent respiration of exclusively heart mitochondria of normal animals of different species. Whereas, with the same substrates, but at a higher concentration of methylglyoxal (7.5 mM), the respiration of mitochondria of other organs of normal animals is not inhibited. Methylglyoxal also inhibits the respiration of slices of rat and toad hearts. But this inhibition is less pronounced. However, methylglyoxal (15 mM) fails to have any effect on perfused toad heart. Using rat heart mitochondria as a model, the effect of methylglyoxal on the oxygen consumption was also tested with different respiratory substrates, electron donors at different segments of the mitochondrial respiratory chain and site-specific inhibitors to identify the specific respiratory complex which might be involved in the inhibitory effect of methylglyoxal. The results strongly suggest that methylglyoxal inhibits the electron flow through complex I of rat heart mitochondrial respiratory chain. Moreover, lactaldehyde (0.6 mM), a catabolite of methylglyoxal, can exert a protective effect on the inhibition of rat heart mitochondrial respiration by methylglyoxal (2.5 mM). The effect of methylglyoxal on heart mitochondria as described in the present paper is strikingly similar to the results of our previous work with mitochondria of Ehrlich ascites carcinoma cells and leukemic leukocytes. We have recently proposed a new hypothesis on cancer which suggests that excessive ATP formation in cells may lead to malignancy. The above mentioned similarity apparently provides a solid experimental foundation for the proposed hypothesis which has been discussed.

Animals↗

PubMed1997

Hepatocyte nuclear factor 3beta is involved in pancreatic beta-cell-specific transcription of the pdx-1 gene.

The mammalian homeobox gene pdx-1 is expressed in pluripotent precursor cells in the dorsal and ventral pancreatic bud and duodenal endoderm, which will produce the pancreas and the rostral duodenum. In the adult, pdr-1 is expressed principally within insulin-secreting pancreatic islet beta cells and cells of the duodenal epithelium. Our objective in this study was to localize sequences within the mouse pdx-1 gene mediating selective expression within the islet. Studies of transgenic mice in which a genomic fragment of the mouse pdx-1 gene from kb -4.5 to +8.2 was used to drive a beta-galactosidase reporter showed that the control sequences sufficient for appropriate developmental and adult specific expression were contained within this region. Three nuclease-hypersensitive sites, located between bp -2560 and -1880 (site 1), bp -1330 and -800 (site 2), and bp -260 and +180 (site 3), were identified within the 5'-flanking region of the endogenous pdx-1 gene. Pancreatic beta-cell-specific expression was shown to be controlled by sequences within site 1 from an analysis of the expression pattern of various pdr-1-herpes simplex virus thymidine kinase promoter expression constructs in transfected beta-cell and non-beta-cell lines. Furthermore, we also established that this region was important in vivo by demonstrating that expression from a site 1-driven beta-galactosidase reporter construct was directed to islet beta-cells in transgenic mice. The activity of the site 1-driven constructs was reduced substantially in beta-cell lines by mutating a hepatocyte nuclear factor 3 (HNF3)-like site located between nucleotides -2007 and -1996. Gel shift analysis indicated that HNF3beta present in islet beta cells binds to this element. Immunohistochemical studies revealed that HNF3beta was present within the nuclei of almost all islet beta cells and subsets of pancreatic acinar cells. Together, these results suggest that HNF3beta, a key regulator of endodermal cell lineage development, plays an essential role in the cell-type-specific transcription of the pdx-1 gene in the pancreas.

Animals↗