Regulation of mammalian pyruvate dehydrogenase alpha subunit gene expression by glucose in HepG2 cells

We report the effect of glucose on the expression of the gene encoding the pyruvate dehydrogenase (E1) alpha subunit (E1alpha) in human hepatoma (HepG2) cells. Total pyruvate dehydrogenase complex activity as well as the levels of protein and mRNA of the E1alpha subunit were significantly increased in HepG2 cells cultured in medium containing 16.7 mM glucose compared with 1.0 mM glucose for a period of 4 weeks. The level of E1alpha mRNA was elevated approx. 2-fold in HepG2 cells cultured for 24 h in medium containing 16.7 mM glucose compared with 1 mM glucose. This effect was specific to glucose and independent of insulin. Nuclear run-on assays and promoter analysis indicate that the glucose-induced increases in the levels of E1alpha mRNA in HepG2 cells are due to increased transcription of the human E1alpha (PDHA1) gene. Mutational analysis of the E1alpha promoter region has identified two regions, from -78 to -73 bp (CCCCTG) and from -8 to -3 bp (GCGGTG), that are responsible for the effect of glucose on promoter activity; the former exhibits a larger effect. These two sequences represent new variations of the carbohydrate-response element that has been identified in other genes. The stimulation of E1alpha promoter activity by glucose was abolished by okadaic acid at 100 nM but not at 5 nM, suggesting that glucose-mediated regulation of pyruvate dehydrogenase complex E1alpha gene transcription involves a phosphorylation/dephosphorylation mechanism, possibly involving protein phosphatase-1.

Detection of human papillomavirus (HPV) in sinonasal inverted papillomas using polymerase chain reaction (PCR)

Paraffin-embedded tissues of 42 sinonasal inverted papillomas were subjected to polymerase chain reaction using type-specific primers pairs of HPV 6, 11, 16, 18, and 33. Two cases of HPV 11 and one of HPV 6 were amplified in 36 samples of benign inverted papilloma, and two cases of HPV 16 were amplified in five samples of inverted papilloma with co-existing squamous cell carcinoma. Inverted papillomas recurred in 1 (16%) of 6 cases exhibiting dysplasia, and in 3 (10%) of 30 cases not exhibiting dysplasia. Inverted papillomas also recurred in 2 (66%) of 3 cases positive for HPV, and in 2 (6%) of 33 cases negative for HPV. These results suggest that HPV may be involved in the pathogenesis of inverted papillomas, may cause malignant transformation of inverted papillomas, and that there may be an apparent relationship between HPV infection and the recurrence of sinonasal inverted papillomas.

Molecular cloning of a light-inducible gene (lipA) encoding a novel pilin from Arthrobacter photogonimos

Development of pili on cells of Arthrobacter photogonimos is induced by photo-oxidative conditions. The nucleotide sequence was determined of a light-inducible gene (lipA) that encodes the precursor of a light-inducible pilin (designated LIP), a polypeptide of 212 amino acids. The N-terminal leader peptide includes a typical signal sequence with a consensus cleavage site for signal peptidase 1 after residue 28, which should generate N-terminal arginine. However, the next amino acid, alanine, is the N-terminal residue of the mature protein. The abundance of charged amino acids (27% of total), a calculated pI of 9.98, and recovery of mostly monomers when cells were washed with 1 M NaCl suggest that electrostatic interactions play a dominant role in association of LIP, a novel mechanism for assembly of pili.

Targeted disruption of the murine dihydrolipoamide dehydrogenase gene (Dld) results in perigastrulation lethality

The Dld gene product, known as dihydrolipoamide dehydrogenase or the E3 component, catalyzes the oxidation of dihydrolipoyl moieties of four mitochondrial multienzyme complexes: pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, branched-chain alpha-ketoacid dehydrogenase, and the glycine cleavage system. Deficiency of E3 activity in humans results in various degrees of neurological dysfunction and organic acidosis caused by accumulation of branched-chain amino acids and lactic acid. In this study, we have introduced a null mutation into the murine Dld gene (Dldtm1mjp). The heterozygous animals are shown to have approximately half of wild-type activity levels for E3 and all affected multienzyme complexes but are phenotypically normal. In contrast, the Dld-/- class dies prenatally with apparent developmental delay at 7.5 days postcoitum followed by resorption by 9.5 days postcoitum. The Dld-/- embryos cease to develop at a time shortly after implantation into the uterine wall when most of the embryos have begun to gastrulate. This null phenotype provides in vivo evidence for the requirement of a mitochondrial oxidative pathway during the perigastrulation period. Furthermore, the early prenatal lethal condition of the complete deficiency state may explain the low incidence of detectable cases of E3 deficiency in humans.

Prolonged mivacurium infusion in young and elderly adults

PURPOSE

This study was designed to evaluate pharmacodynamically and pharmacokinetically if the cis-cis isomer of mivacurium contributed to neuromuscular block during prolonged infusions lasting more than four hours in young adult and elderly (> 60 yr) patients.

METHODS

The mechanomyogramic neuromuscular response of the adductor pollicis was recorded in 32 adults 18-59 yr. and 19 elderly (> 60 yr.) patients during N2O:O2:opioid anaesthesia. The mivacurium infusion rate was adjusted to maintain single twitch depression at 95 +/- 4% of control. Blood samples were taken every 30 min to determine the plasma concentration of cis-cis isomer of mivacurium. At the end of the surgical procedure, patients were allowed to recover spontaneously to at least 25% of control twitch response.

RESULTS

The mean mivacurium infusion requirement to maintain 97 +/- 1 (mean +/- SD)% depression of the twitch response was 6.0 +/- 0.4 micrograms.kg-1.min-1 in young adults, and 4.3 +/- 0.3 micrograms.kg-1.min-1 in elderly patients (P < 0.001). The infusion requirement in patients with low plasma cholinesterase activity was the lowest 2.4 +/- 1.2 micrograms.kg-1.min-1. Plasma cis-cis isomer concentrations reached peak levels within one-two hours and remained relatively constant throughout the duration of infusion even in patients with low cholinesterase activity. There was no relationship between duration of infusion, plasma concentrations of cis-cis isomer and the early recovery indices of mivacurium (up to 25%). Neuromuscular transmission recovered adequately with or without antagonism in all patients.

CONCLUSION

When the mivacurium infusion was titrated to maintain 95 +/- 4% twitch depression, the plasma concentration of the cis-cis isomer did not increase during prolonged infusions (four hours) and neuromuscular transmission recovers satisfactorily.

Characterization of the mouse dihydrolipoamide dehydrogenase (Dld) gene: genomic structure, promoter sequence, and chromosomal localization

The mouse dihydrolipoamide dehydrogenase (Dld) gene has been cloned, characterized, and mapped. This nuclear gene encodes a mitochondrial protein that is shared among several alpha-keto acid dehydrogenase complexes and the glycine cleavage system. The Dld gene is contained within an approximately 21-kb region and consists of 14 exons ranging in size from 69 to 521 nucleotides. The open reading frame codes for a preprotein of 509 amino acids with a predicted mature protein of 474 amino acids that is highly conserved among mammalian species (> 90% identical). Primer extension analyses have shown the gene to have transcription initiation sites with tissue-specific differences in relative utilization. The 5' flanking region is G-C rich and lacks a TATA box, but does contain initiator element and multiple transcription factor-binding consensus sequences. Northern blot analysis shows that the Dld mRNA in various tissues is approximately 2.4 kb in size. The Dld gene has been localized to the proximal region of chromosome 12, approximately 21 cM from the centromere.

Sperm as a carrier to introduce an exogenous DNA fragment into the oocyte of Japanese abalone (Haliotis divorsicolor suportexta)

We investigated gene transfer in abalone via electroporated sperm. The mobility of sperm electroporated either in seawater or in marine invertebrate physiological solution was as good as that of the control group. The fertilization rate reached as high as 94.7-99.6% (93.0-99.7% for the control group) when 200 eggs were fertilized by 10(6) or 10(7) sperm treated with electroporation at 10 kV and 2(7) pulses for six cycles. Moreover, the fertilization rate of sperm electroporated in the presence of foreign DNA (opAFP-2000CAT) ranging from 0.1 to 3.2 micrograms and at voltages ranging from 2 to 10 kV, at 2(7) or 2(11) pulses for six or 12 cycles showed no differences from the control sperm. After DNase digestion, the genome of the electroporated sperm was analysed by polymerase chain reaction, and it was shown that a 138-bp product was amplified, corresponding to the transgene's amplification product. Southern blotting also showed that a positive band located at the same position as that of opAFP-2000CAT was found in the electroporated sperm after DNase treatment. Analysis by PCR of the genome isolated from a trochophore-stage abalone larva, derived from sperm electroporated with 3.2 micrograms opAFP-2000CAT, showed the existence of foreign DNA in 13 out of 20 examined samples (65%). The integration of the transferred DNA into the genome of transgenic abalone was also shown by Southern blot analysis. Furthermore, CAT activity was positive for the experimental larvae, but the level of CAT expression was lower than that of larvae derived from sperm electroporated with pCAT-Control vector, driven by SV40 promoter and enhancer sequences. These results demonstrate the potential for the use of sperm as mass gene transfer strategy in marine mollusks such as abalone.

Stress analysis of a cantilevered fixed partial denture with normal and reduced bone support

A two-dimensional finite element model was constructed to analyze the simulated mechanical behavior of a cantilevered fixed partial denture. The variations of the models were made by altering the degree of bone support, the number of splinted abutments, and the length of the pontics. High stress concentrations were observed around the connectors of the fixed prosthesis and the tooth closest to the cantilever. Reduced bone support increased the deflection and stress concentrations. There was reduction in displacement and stress concentration when the teeth were splinted together. To improve the prognosis of the fixed partial denture cantilever, the number of abutments should be increased and the number of pontics decreased.

Pseudocholinesterase-mediated hydrolysis is superior to neostigmine for reversal of mivacurium-induced paralysis in vitro

BACKGROUND

The metabolic hydrolysis of mivacurium (and succinylcholine) is markedly impaired in the presence of hereditary or acquired defects of pseudocholinesterase. Clinical reports are conflicting as to the utility of anticholinesterases, in the reversal of mivacurium paralysis. In the current study, the role of exogenous cholinesterases and/or of anticholinesterase, neostigmine, in the reversal of deep mivacurium-induced paralysis, was studied. The rat phrenic-diaphragm preparation, in a fixed volume of Krebs solution, was chosen to eliminate the confounding effects on the dissipation of neuromuscular effects caused by hydrolysis, elimination, and redistribution of the drug.

METHODS

In the phrenic-diaphragm preparation, mivacurium was administered to obtain >90% single twitch inhibition. Single twitch responses (0.1 Hz) were monitored for 60 min, after which the response to train-of-four stimulation was tested. The reversal of mivacurium by 0.5, 1.0, or 2.0 units/ml of (true) acetylcholinesterase, bovine pseudocholinesterase, or human plasma cholinesterase and by neostigmine, 0.1, 1.0, or 10.0 micrograms/ml tested. The efficacy of human plasma cholinesterase, 1 unit/ml in combination with each of the above neostigmine concentrations, also was examined. The reversal of succinylcholine-induced paralysis by the acetylcholinesterase, bovine pseudocholinesterase, or human plasma cholinesterase (1 unit/ml) alone and in the presence of neostigmine (10.0 micrograms/ml) was additionally tested as a positive control. A train-of-four ratio > 0.75 was considered adequate reversal.

RESULTS

Acetylcholinesterase was a poor hydrolyzer of mivacurium, as bioassayed by reversal of paralysis. Bovine pseudocholinesterase in concentrations of 0.5 and 1.0 units/ml did not effectively reverse single twitch and train-of-four responses by 60 min, but bovine pseudocholinesterase (2 units/ml) and all concentrations of human plasma cholinesterase did. Neostigmine alone, tested at all concentrations, was an incomplete reversal drug. Clinical or therapeutic concentrations (0.1 and 1.0 micrograms/ml) of neostigmine did not, but pharmacologic concentrations (10 micrograms/ml) interfere with the efficacy of human plasma cholinesterase (1 unit/ml). Bovine pseudocholinesterase and human plasma cholinesterase equally reversed the effects of succinylcholine but acetylcholinesterase did not, whereas the addition of 10 micrograms/ml neostigmine to the enzymes inhibited the reversal of succinylcholine.

CONCLUSIONS

Human plasma cholinesterase will reverse mivacurium more effectively than bovine pseudocholinesterase, but both will effectively reverse succinylcholine. Acetylcholinesterase has no effects on either relaxant. The anticholinesterase neostigmine was an incomplete reversal drug. Pharmacologic concentrations of anticholinesterases do, while clinical or therapeutic concentrations do not, completely inhibit the metabolic activity of pseudocholinesterases.

The influence of the age of the rat on the neuromuscular response to mivacurium in vitro

The effective concentrations of mivacurium induced neuromuscular block were studied in the phrenic nerve-hemidiaphragm preparations of forty male Sprague-Dawley rats in four groups according to body weight, 10 g, 25 g, 100 g, and 200 g. Mivacurium was added to the Krebs' solution to obtain an initial concentration of 0.275 microgram.ml-1 (2.5 x 10(-7) mole.litre-1). Thereafter, the concentration of mivacurium was increased in increments to obtain more than 90% neuromuscular twitch inhibition at 0.1 Hz. Data were analysed by probit and logistic models. The two statistical techniques yielded very similar results, almost identical values of EC50 and EC95. There were significant decreases in the effective concentrations of mivacurium needed to depress the twitch response in neonatal rats (10 g) compared to older rats. No significant differences were observed between 25, 100 and 200 g rats. We conclude that the neonatal neuromuscular junctions of rats show increased sensitivity to mivacurium related to pharmacodynamic factors.

Soft drugs. XX. Design, synthesis, and evaluation of ultra-short acting beta-blockers

A new type of ultra-short acting beta-blocker which might prove advantageous in treating acute arrhythmias was designed, synthesized and investigated. Based on the soft drug "inactive metabolite approach," the inactive phenylacetic acid metabolite of both metoprolol and atenolol was reactivated by esterification with sulfur-containing aliphatic alcohols. Since the sulfur-containing moieties are labile to the ubiquitous esterases, the new compounds should be inactivated by a one step enzymatic cleavage back to the inactive phenylacetic acid derivative. Pharmacological and pharmacokinetic profiles of the new compounds were evaluated in rats and rabbits. Isoproterenol-induced tachycardia was inhibited with short-term infusion of each compound. This tachycardia blocking effect rapidly disappeared upon termination of infusion, while beta-blocking activity was 2-4-fold longer after comparable doses of the short-acting beta-blocker, esmolol. The rapid recovery from the beta-receptor blockade is believed due to fast hydrolysis of the soft drugs in the body. This is supported from in vitro results showing the t1/2 of esmolol is about 10-fold longer than the new soft drugs in rat, rabbit, dog and human blood. Hydrolysis studies in phosphate buffered solutions indicated that the esters are labile to base-catalyzed hydrolysis. However, the relative t1/2 values measured in biological media compared to phosphate buffered solution clearly support rapid enzymatic cleavage of the soft drugs. Interestingly, one of the soft beta-blockers, the sulfonyl ester derivative, showed a unique property of exhibiting good beta-receptor blocking activity without significant hypotensive action.

Influence of epithelium removal on allergic contraction of isolated tracheal smooth muscle

Sensitized guinea pig tracheal preparations with epithelium removed were more sensitive to acetylcholine, histamine substance P, and barium chloride than those with epithelium intact. EC50 of them obtained in the preparations with epithelium removed dramatically decreased to 1/6-1/30 vs that obtained in epithelium intact ones. The amplitudes of contractions of epithelium-removed preparations induced by antigen-antibody reaction or electric field stimulation increased by 50%-100% vs the control. These results indicated that the epithelium had important modulative effects on the airway, especially on its allergic contractions.

Case of difficult intubation overcome by the laryngeal mask airway

A case of difficult intubation is described in which the problem was overcome by use of the laryngeal mask airway (LMA). The patient had difficulty in mouth opening due to severe burn scar contracture around the mouth and limited access prevented tracheal intubation. The use of LMA is shown to have obviated the need for tracheal intubation in the case of a patient whose injuries would have made this technique difficult.

[Transcatheter hepatic arteriography combined with ultrasound in the diagnosis of space occupying lesions]

Super-selective hepatic arteriography was performed in 40 patients with liver neoplasma by injecting H2O2. The final diagnosis were as follows: 23 hepatic cases of carcinoma, 14 patients had cavernous hemangioma, 1 case of hepato-cirrhosis and 2 cases excluding neoplasma. According the contrast, the entrance of H2O2 into neoplasma could be divided into four types: rapid-filling, middle speed-filling, low speed-filling, enclostic but no entering. The acoustic contrast technique, pathological basis, and qualitative diagnosis were also discussed.

A two-dimensional stress analysis comparing fixed prosthodontic approaches to the tilted molar abutment

A two-dimensional finite element method was used to analyze the changes in mechanical behavior of the supporting structures when a fixed prosthesis replaced a mandibular first molar. In the unrestored situation, as the degree of bone resorption increased there was a corresponding increase in stress in the periodontium. Tilting of the molar abutment induced additional stress on the mesial side of the root. The presence of a fixed prosthesis markedly reduced the magnitude and distribution of stress in the periodontium. The mechanical advantage obtained by a fixed prosthesis was greater in the situation of a tilted second molar with reduced bone support than with higher bone levels.

[X-ray diagnosis of primary rhabdomyosarcoma of long bone (report of 4 cases)]

Four cases of primary rhabdomyosarcoma of long bone were reported, all confirmed by operation and pathology. There were 3 male and 1 female. The femur was involved in 1 case and tibia in 3. Based on the radiologic manifestations the tumor could be divided into two different types: (1) Osteolytic form: Presenting as large area of osteolytic destruction without periosteal reaction; (2) Mixed form: In addition to patchy osteolytic destruction, calcification or dense tumor bone in the medullary cavity or soft tissue can be seen, often associated with periosteal reaction.

[The effect of composition on the mechanical properties of composite resin]

The objective of this investigation was to determine whether the composition of composite resin affects the amount of residual monomers and the strength of resin. Six types of resin composition were designed and 30 composite resin specimens were made in glass mold of 6mm diameter and 3mm height. The residual monomer of each specimen was extracted by 10cc ethanol solution for 1, 2, and 3 days of experiment. UV/Vis spectrophotometer was used to estimate the amount of residual monomer of the specimen, and universal testing machine was used to test the diametral tensile strength of the composite resin. The results were as follow; 1. Composite resins of 1% benzoyl peroxide concentration released the higher level of residual monomers than the resin of 0.8% benzoyl peroxide concentration. 2. t-Butylaminoethylmethacrylate.HF of 17% concentration exhibited the greater level of residual monomer than the other resin monomers. 3. As the concentration of the trimethylolpropane trimethacrylate increased, the amount of Bis-GMA residual monomer increased. 4. Composite resin of 1% benzoyl peroxide concentration showed higher tensile strength than the resin of 0.8% benzoyl peroxide concentration. 5. As the concentration of trimethylolpropane trimethacrylate increased above 50%, the strength of the composite resin decreased.

Residual concentrations of propanil, TCAB, and other pesticides in rice-growing of soils in the United States, 1972

Ninety-nine soil samples from the rice-growing states of Arkansas, California, Louisiana, Mississippi, and Texas were collected, primarily to monitor the herbicide propanil. No residual concentrations of propanil were detected in any of these samples, but TCAB, a propanil transformation product, was detected in six samples at concentrations ranging from 0.01 ppm to 0.05 ppm. Organochlorine and organphosphorus pesticide determinations were also performed. The compounds dieldrin, aldrin, and DDT and its metabolites were found more frequently; endrin and chlordane were found less frequently. The organophosphorus pesticides diazinon and parathion were detected occasionally.

Adenylate kinase from Rhodospirillum rubrum

A partial purification and some properties of adenylate kinase from the photosynthetic bacterium Rhodospirillum rubrum are described.

Continuous dehydrogenation of a steroid with immobilized microbial cells: effect of an exogenous electron acceptor

Whole cells of Pseudomonas testosteroni, induced to synthesize steroid-transforming enzymes beforehand, have been immobilized by entrapment in polyacrylamide gel. The immobilized cells have been used to catalyze the continuous delta1-dehydrogenation of Reichstein's substance S under various conditions in the presence of phenazine methosulfate (PMS), an electron acceptor for the cell-free delta1-dehydrogenase. The presence of PMS substantially increases the rate of reaction when fed with the steroid substrate to a continuous stirred tank reactor containing the immobilized cells. The operational half-life of the delta1-dehydrogenase activity of the cells, about 103 hr under the best operating conditions, is essentially unaffected by the presence of PMS. Though the acceleration of the reaction may be due to PMS-mediated passage of electrons from some component in the electron transport chain to molecular oxygen, the lack of a similar effect with methylene blue is consistent with the conclusion that PMS functions directly as the electron acceptor for the delta1-dehydrogenase.

Photosynthetic regeneration of ATP using bacterial chromatophores

We have demonstrated the use of bacterial chromatophores for the continuous photosynthetic regeneration of ATP from ADP in an ultrafiltration reactor. Biphasic kinetics of the degradation of chromatophore activity are described. Using chromatophores in combination with the enzyme adenylate kinase, we have also demonstrated continuous regeneration of ATP from AMP.

Preparation and properties of bacterial chromatophores entrapped in polyacrylamide

The immobilization of Rhodospirillum rubrum chromatophores was successfully performed by entrapping them in polyacrylamide. Their photophosphorylating activity was about 40% of native chromatophores. The temperature and pH optima for immobilized chromatophores were similar to the native photosynthetic apparatus and kinetic parameters showed that the rate of photophosphorylation in polyacrylamide particles was diffusion controlled. Light penetration of the gel particles was not a limiting parameter. Immobilization considerably increased the stability of the chromatophores towards denaturation.

Organochlorine pesticide residues in sugarbeet pulps and molasses from 16 states, 1971

Sugarbeet pulp and molasses from 57 processing plants in 16 States were sampled for pesticide residues. No molasses samples contained detectable pesticide residues, but about 15 percent of the pulp samples contained low levels of dieldrin, toxaphene, or DDT and its degradation products. Sugarbeet pulp, when used as animal feed, can be a source of pesticidal contamination of human food.