Novel modeling concept for evaluating the effects of cadmium and copper on heterotrophic growth and lysis rates in activated sludge process

A new modeling concept to evaluate the effects of cadmium and copper on heterotrophic growth rate constant (mu(H)) and lysis rate constant (b(H)) in activated sludge was introduced. The oxygen uptake rate (OUR) was employed to measure the constants. The results indicated that the mu(H) value decreased from 4.52 to 3.26 d(-1) or by 28% when 0.7 mg L(-1) of cadmium was added. Contrarily the b(H) value increased from 0.31 to 0.35 d(-1) or by 11%. When adding 0.7 mg L(-1) of copper, the mu(H) value decreased to 2.80 d(-1) or by 38%. The b(H) value increased to 0.42 d(-1) or by 35%. After regression, the inhibitory effect was in a good agreement with non-competitive inhibition kinetic. The inhibition coefficient values for cadmium and copper were 1.82 and 1.21 mg L(-1), respectively. The relation between the b(H) values and heavy metal concentrations agreed with exponential type well. The heavy metal would enhance b(H) value. Using these data, a new kinetic model was established and used to simulate the degree of inhibition. It was evident that not only the inhibitory effect on mu(H) but also that the enhancement effect on b(H) should be considered when heavy metal presented.

Endotoxin tolerance of RAW264.7 correlates with p38-dependent up-regulation of scavenger receptor-A

Pre-exposure to lipopolysaccharide (LPS) leads to hyposensitivity to secondary LPS stimulation, known as endotoxin tolerance. The role of macrophage scavenger receptor-A (SR-A) in endotoxin tolerance is unknown. In this study, LPS was shown to induce SR-A expression in the mouse macrophage cell line, RAW264.7, in dose- and time-dependent manners, which correlated with inflammatory cytokine suppression in RAW264.7 on secondary LPS stimulation. Over-expression of SR-A in RAW264.7 suppressed tumour necrosis factor (TNF)-alpha release and nuclear factor (NF)-kappa B activation, demonstrating the involvement of SR-A in endotoxin tolerance. LPS-pre-treated RAW264.7 cells could bind and internalize more fluorescein isothiocyanate (FITC)-LPS than untreated cells and both the SR-A ligand, fucoidan, and anti-SR-A 2F8 antibodies completely suppressed LPS-induced binding and internalization of FITC-LPS by RAW264.7. LPS-induced SR-A expression on RAW264.7 was completely suppressed by the p38-specific inhibitor, SB203580, but not by inhibition of toll-like receptor 4 (TLR4) signalling with MTS510, demonstrating that p38- but not TLR4-dependent up-regulation of SR-A was involved in endotoxin tolerance through binding and internalization of LPS.

Biostabilization assessment of MSW co-disposed with MSWI fly ash in anaerobic bioreactors

Municipal solid waste incinerator (MSWI) fly ash has been examined for possible use as landfill interim cover. For this aim, three anaerobic bioreactors, 1.2m high and 0.2m in diameter, were used to assess the co-digestion or co-disposal performance of MSW and MSWI fly ash. Two bioreactors contained ratios of 10 and 20 g fly ash per liter of MSW (or 0.2 and 0.4 g g(-1) VS, that is, 0.2 and 0.4 g fly ash per gram volatile solids (VS) of MSW). The remaining bioreactor was used as control, without fly ash addition. The results showed that gas production rate was enhanced by the appropriate addition of MSWI fly ash, with a rate of approximately 6.5l day(-1)kg(-1)VS at peak production in the ash-added bioreactors, compared to approximately 4l day(-1)kg(-1)VS in control. Conductivity, alkali metals and VS in leachate were higher in the fly ash-added bioreactors compared to control. The results show that MSW decomposition was maintained throughout at near-neutral pH and might be improved by release of alkali and trace metals from fly ash. Heavy metals exerted no inhibitory effect on MSW digestion in all three bioreactors. These phenomena indicate that proper amounts of MSWI fly ash, co-disposed or co-digested with MSW, could facilitate bacterial activity, digestion efficiency and gas production rates.

Solubility of heavy metals added to MSW

This paper aims to investigate the six heavy metal levels (Cd, Cr, Cu, Pb, Ni and Zn) in municipal solid waste (MSW) at different pHs. It intends to provide the baseline information of metals solubility in MSW co-disposed or co-digested with MSW incinerator ashes in landfill or anaerobic bioreactors or heavy metals contaminated in anaerobic digesters. One milliliter (equal to 1mg) of each metal was added to the 100ml MSW and the batch reactor test was carried out. The results showed that higher HNO3 and NaOH were consumed at extreme pH of 1 and 13 compared to those from pH 2 to 11 due to the comparably higher buffer capacity. Pb was found to have the least soluble level, highest metal adsorption (%) and highest partitioning Kd (lg(-1)) between pH 3 and 12. In contrast, Ni showed the highest soluble level, lowest metal adsorption (%) and lowest Kd (lg(-1)) between pH 4 and 12. Except Ni and Cr, other four metals seemed to show the amphibious properties as comparative higher solubility was found in the acidic and basic conditions.

Differential effects of isoflavones, from Astragalus membranaceus and Pueraria thomsonii, on the activation of PPARalpha, PPARgamma, and adipocyte differentiation in vitro

Compounds that target the peroxisome proliferator-activated receptors PPARalpha and PPARgamma are used to correct dyslipidemia and to restore glycemic balance, respectively. Because the majority of diabetic patients suffer from atherogenic lipid abnormalities, in addition to insulin resistance, ligands are required that can activate both PPARalpha and PPARgamma. In this study, we used chimeric PPARalpha/gamma reporter-gene bioassays to screen herbal extracts with purported antidiabetic properties. Extracts of Astragalus membranaceus and Pueraria thomsonii significantly activated PPARalpha and PPARgamma. Bioassay-guided fractionation resulted in the isolation of the isoflavones, formononetin, and calycosin from Astragalus membranaceus, and daidzein from Pueraria thomsonii as the PPAR-activating compounds. We investigated the effects of these and 2 common isoflavones, genistein and biochanin A, using chimeric and full-length PPAR constructs in vitro. Biochanin A and formononectin were potent activators of both PPAR receptors (EC50 = 1-4 micromol/L) with PPARalpha/PPARgamma activity ratios of 1:3 in the chimeric and almost 1:1 in the full-length assay, comparable to those observed for synthetic dual PPAR-activating compounds under pharmaceutical development. There was a subtle hierarchy of PPARalpha/gamma activities, indicating that biochanin A, formononetin, and genistein were more potent than calycosin and daidzein in chimeric as well as full-length receptor assays. At low doses, only biochanin A and formononetin, but not genistein, calycosin, or daidzein, activated PPARgamma-driven reporter-gene activity and induced differentiation of 3T3-L1 preadipocytes. Our data suggest the potential value of isoflavones, especially biochanin A and their parent botanicals, as antidiabetic agents and for use in regulating lipid metabolism.

Population structure of wild bananas, Musa balbisiana, in China determined by SSR fingerprinting and cpDNA PCR-RFLP

Both demographic history and dispersal mechanisms influence the apportionment of genetic diversity among plant populations across geographical regions. In this study, phylogeography and population structure of wild banana, Musa balbisiana, one of the progenitors of cultivated bananas and plantains in China were investigated by an analysis of genetic diversity of simple sequence repeat (SSR) fingerprint markers and cpDNA PCR-RFLP. A chloroplast DNA (cpDNA) genealogy of 21 haplotypes identified two major clades, which correspond to two geographical regions separated by the Beijiang and Xijiang rivers, suggesting a history of vicariance. Significant genetic differentiation was detected among populations with cpDNA markers, a result consistent with limited seed dispersal in wild banana mediated by foraging of rodents. Nuclear SSR data also revealed significant geographical structuring in banana populations. In western China, however, there was no detected phylogeograpahical pattern, possibly due to frequent pollen flow via fruit bats. In contrast, populations east of the Beijiang River and the population of Hainan Island, where long-range soaring pollinators are absent, are genetically distinct. Colonization-extinction processes may have influenced the evolution of Musa populations, which have a metapopulation structure and are connected by migrating individuals. Effective gene flow via pollen, estimated from the nuclear SSR data, is 3.65 times greater than gene flow via seed, estimated from cpDNA data. Chloroplast and nuclear DNAs provide different insights into phylogeographical patterns of wild banana populations and, taken together, can inform conservation practices.

Growth dynamics of human leiomyoma cells and inhibitory effects of the peroxisome proliferator-activated receptor-γ ligand, pioglitazone

Uterine leiomyomas (fibroids) are the most frequent tumour of the female reproductive tract and are the primary cause of hysterectomies in women worldwide. Effective treatment options are few. In a search for alternative treatments, we have established primary cultures of human leiomyoma cells and adjacent myometrial tissues, and documented their growth dynamics in response to estradiol (E2) and pioglitazone (PIO), a peroxisome proliferation-activated receptor-gamma (PPARgamma) ligand, currently in clinical use for type II diabetes mellitus. Human uterine primary cell cultures display morphology and desmin content consistent with their smooth muscle origin. Surprisingly, leiomyoma cells exhibited slower proliferation patterns relative to matched myometrial cells, both in the absence and presence of E2, suggesting that tumour genesis may not be because of increased growth potential but could be related to suppression of growth-inhibiting factors in vivo. PIO significantly inhibited the cell proliferation of both myometrial and leiomyoma cells in a dose-dependent manner. Our results suggest the possibility of using PPARgamma ligands, such as PIO, as therapeutic agents for the conservative management of uterine fibroids.

A pilot, double-blind, placebo-controlled trial of indinavir in patients with ALS

There is some evidence of retroviral infection in ALS. A randomized, double-blind, placebo-controlled trial of indinavir in ALS was performed to assess safety and efficacy trends. Nephrolithiasis and gastrointestinal side effects were frequent with indinavir treatment. Group differences in the rate of decline were not significant between the groups for the ALS Functional Rating Scale (p = 0.36) or for the secondary variables. The toxicity and negative efficacy trends discourage further indinavir trials in ALS.

Partition and size distribution of heavy metals in the flue gas from municipal solid waste incinerators in Taiwan

This study investigates the partition of heavy metals in both solid and gas phases in the flue gas from municipal solid waste (MSW) incinerators. Six MSW incinerators in Taiwan were examined and heavy metals in the flue gas at the inlets and outlets of air pollution control devices (APCDs) were analyzed. Heavy metals including Hg, Pb, Cd, Zn, Cu and Cr were sampled by USEPA Method 29 and further analyzed using inductively coupled plasma-mass spectroscopy (ICP-MS) and cold vapor atomic absorption spectrometry (CVAAS). Experimental results revealed that the removal efficiencies of the APCDs for the heavy metals Pb, Cd, Zn, Cu and Cr greatly exceeded 90%, but that of Hg did not. Two groups of heavy metals upstream of APCDs were observed. Pb, Cd, Zn, Cu and Cr were present mainly in the solid phase with a solid to gas ratio (S/G) of over 12.3. However, in most cases, mercury appeared mainly in the gas phase with an S/G ratio from 0.15 to 1.04, because it has a low boiling point. Additionally, treatment with the APCDs increased the S/G ratio of mercury because gaseous mercury could be removed by injecting powdered activated carbon (PAC) into the flue gas. Moreover, the distribution of particle sizes in the solid phase was bimodal. Finer particles (d(p)<or=2.5 microm) contained more Pb, Cd, Zn and Cu, whereas coarser particles (d(p)>2.5 microm) contained more Cr and Hg.

Preparation of sulfurized powdered activated carbon from waste tires using an innovative compositive impregnation process

The objective of this study is to develop an innovative compositive impregnation process for preparing sulfurized powdered activated carbon (PAC) from waste tires. An experimental apparatus, including a pyrolysis and activation system and a sulfur (S) impregnation system, was designed and applied to produce sulfurized PAC with a high specific surface area. Experimental tests involved the pyrolysis, activation, and sulfurization of waste tires. Waste-tire-derived PAC (WPAC) was initially produced in the pyrolysis and activation system. Experimental results indicated that the Brunauer-Emmett-Teller (BET) surface area of WPAC increased, and the average pore radius of WPAC decreased, as water feed rate and activation time increased. In this study, a conventional direct impregnation process was used to prepare the sulfurized PAC by impregnating WPAC with sodium sulfide (Na2S) solution. Furthermore, an innovative compositive impregnation process was developed and then compared with the conventional direct impregnation process. Experimental results showed that the compositive impregnation process produced the sulfurized WPAC with high BET surface area and a high S content. A maximum BET surface area of 886 m2/g and the S content of 2.61% by mass were obtained at 900 degrees C and at the S feed ratio of 2160 mg Na2S/g C. However, the direct impregnation process led to a BET surface area of sulfurized WPAC that decreased significantly as the S content increased.

Human renal fibroblasts derived from normal and fibrotic kidneys show differences in increase of extracellular matrix synthesis and cell proliferation upon angiotensin II exposure

Angiotensin II (Ang II) as a vasoactive hormone may be involved in progressive renal interstitial fibrosis. We investigated the influence of Ang II on cell proliferation and synthesis of extracellular matrix (collagen I, III and fibronectin) in human renal fibroblasts derived from normal (TK 173 cell line) and fibrotic (TK 188 cell line) kidneys which possess both Ang II type l and type 2 (AT1 and AT2) receptors. Incubation of the cells with Ang II increased the cell proliferation and the synthesis of extracellular matrix significantly in both cell lines. However, proliferation and extracellular matrix synthesis showed a greater increase in the cells derived from the fibrotic kidney. The Ang II mediated effect on cell proliferation and extracellular matrix synthesis was diminished in the presence of the AT1 receptor blocker losartan in both cell lines. No inhibition was observed using the AT2 receptor blocker PD123319. Ang II induced cell proliferation could be completely inhibited by incubation with human TGF-beta1 antibody. Incubation with Ang II did not affect TGF beta 1 production but in untreated cells TGF-beta 1 content was higher in the cells derived from the fibrotic kidney. This might be the reason for the more sensitive reaction on exposure to Ang II.

[Investigation of reproductive organs of male children and juvenile of the Meng and the Han nationality in Chifeng area]

OBJECTIVES

To investigate the development and the health of reproductive organs of male children and juvenile between the Meng and the Han nationality in the Meng nationality area.

METHODS

Male juvenile(4-18 years old) of the Meng nationality (n = 2,315) and the Han nationality (n = 2,832) were divided into four age groups. Height, weight, length and perimeter of penis, volume of left and right testis and reproductive organs illness were examined.

RESULTS

In 13-18 years group, the developmental speed of reproductive organs was faster in Mongolia male juvenile than that in the Han nationality (P < 0.02). After 13 years old, the developmental speed of reproductive organs of male living in town is faster than that in the country (P < 0.05). Illness of male reproductive organs was common such as hernia, varicocle etc.

CONCLUSIONS

There was difference of developmental status and the prevalence rate of reproductive organs of male children and juvenile between the Meng and the Han nationality.

Inhibition of vasoconstriction by AJ-2615, a novel calcium antagonist with alpha(1)-adrenergic receptor blocking activity in human conduit arteries used as bypass grafts

AIMS

Graft spasm may develop during coronary artery bypass grafting and reversal of spasm is still challenging. The purpose of this study was to investigate the in vitro vascular relaxant properties of AJ-2615 in human internal mammary artery (IMA).

METHODS

We studied 264 IMA rings taken from 65 patients undergoing coronary artery bypass grafting surgery with organ bath technique. The interaction between AJ-2615 and various vasoconstrictors was investigated in two ways.

RESULTS

AJ-2615 caused complete relaxation in methoxamine-contracted IMA rings (100.0+/-0.0%; n = 8) and nearly full relaxation in potassium chloride-contracted IMA rings (91.4+/-5.7%; n = 8) or noradrenaline-contracted IMA rings (89.3+/-2.8%; n = 8). AJ-2615 also induced remarkable relaxation in IMA rings contracted by other vasoconstrictors. In comparison with the alpha1-adrenoceptor antagonist prazosin, AJ 2615 showed similar maximal relaxation in IMA rings contracted by methoxamine or norepinephrine. On the other hand, incubation with AJ-2615 (0.1-1 microM) significantly inhibited all the vasoconstrictor-mediated vasoconstriction except endothelin-1 in a concentration-dependent manner.

CONCLUSIONS

The results suggested that in human IMA, AJ-2615 has an inhibitory effect on vasoconstriction mediated by a variety of vasoconstrictors and the mechanism of relaxation may be related to its calcium antagonism and alpha1-adrenergic receptor blocking activity. AJ-2615 may have important clinical implications for patients undergoing coronary artery bypass surgery for reversing and preventing graft spasm.

Vascular endothelial growth factor-mediated endothelium-dependent relaxation is blunted in spontaneously hypertensive rats

The vasodilatory effect of VEGF has not been characterized in the setting of hypertension. This study investigated the in vitro vasorelaxant effects of VEGF in organ chambers in the aorta of the adult (12-week-old) spontaneously hypertensive rats (SHR), young (4-week-old) SHR without hypertension, and age-matched Wistar-Kyoto (WKY) rats compared with acetylcholine (ACh). Cumulative concentration-relaxation curves were established for VEGF (approximately 10(-12)-10(-8.5) M) and ACh (approximately 10(-10)-10(-5) M) in U46619 (10(-8) M)-induced contraction. VEGF induced endothelium-dependent relaxation that was significantly reduced in the adult SHR compared with the age-matched WKY control (87.8 +/- 2.8 versus 61.4 +/- 8.6%, P = 0.01). These responses were significantly attenuated by pretreatment with N(omega)-nitro-L-arginine (L-NNA, 300 microM) alone (SHR: 25.1 +/- 1.9%; WKY: 21.0 +/- 2.6%; P = 0.01) or indomethacin (7 microM) + L-NNA (SHR: 30.2 +/- 2.1%; WKY: 35.0 +/- 2.9%; P = 0.01). Further addition of oxyhemoglobin (20 microM) abolished the residual relaxation and reduced the relaxation induced by nitroglycerin. ACh induced similar responses to VEGF. In contrast, pretreatment with indomethacin alone enhanced VEGF- or ACh-induced relaxations and the effect was greater in the adult SHR than in WKY rats. In contrast to the adult SHR versus WKY rats, there were no significant differences of VEGF- or ACh-induced relaxations between young SHR and WKY rats. The results demonstrate that VEGF induces endothelium- or nitric oxide-dependent relaxation, which is blunted in the adult SHR. The mechanism of this impairment may be related to decreased release of NO although increased release of contracting factors from the dysfunctional endothelium may also be involved.

Effects of potassium channel opener aprikalim on the receptor-mediated vasoconstriction in the human internal mammary artery

BACKGROUND

Arterial grafts for coronary artery bypass grafting such as the internal mammary artery (IMA) may develop spasm perioperatively. The purpose of this study was to investigate the effects of the potassium channel opener, aprikalim, on the receptor-mediated vasoconstriction in the human IMA in vitro.

METHODS

We studied 160 IMA rings taken from coronary artery surgery in organ baths. The interaction between aprikalim and four vasoconstrictors 5-hydroxytryptamine (5-HT), norepinephrine (NE), endothelin-1 (ET-1), and angiotensin II (AII) was investigated in two ways.

RESULTS

Aprikalim relaxed IMA rings precontracted by the vasoconstrictors to 66.40 +/- 5.9% for 5-HT (EC50: -6.78 +/- 0.26 LogM), 57.40 +/- 5.5% for NE (-6.54 +/- 0.39 LogM), 81.00 +/- 6.7% for ET-1 (-6.58 +/- 0.26 LogM), and 93.90 +/- 2.5% for AII (-7.80 +/- 0.23 LogM). The relaxation in endothelium-denuded rings contracted by AII was similar to that in the endothelium-intact rings. The relaxation was attenuated by glibenclamide (3 microM) in 5-HT or NE-precontracted IMA. Pretreatment with aprikalim at 1 microM depressed AII-induced contraction (33.20 +/- 7.5% versus 59.70 +/- 7.3%, p < 0.01) but only shifted the curves rightward for 5-HT or NE (EC50 3.1 or 4.3-folds higher, p < 0.05), whereas at 30 microM it also significantly depressed the maximal contraction for 5-HT (35.70 +/- 4.9% versus 103.30 +/- 9.8%, p < 0.001) and NE (90.60 +/- 15.6% versus 125.60 +/- 7.9%, p < 0.05). In contrast, aprikalim did not significantly depress the contraction induced by ET-1 (p > 0.05).

CONCLUSIONS

We conclude that aprikalim has vasorelaxant effects on IMA and the effect is vasoconstrictor-selective and endothelium-independent. Aprikalim may provide clinically useful vasorelaxant effects in coronary bypass surgery.

Inhibition of vasoconstriction by angiotensin receptor antagonist GR117289C in arterial grafts

BACKGROUND

Angiotensin II (AII) has been suggested to be one of the important factors for genesis of graft spasm in coronary artery bypass surgery. The aim of this work was to investigate the effects of the nonpeptide angiotensin receptor AT1 antagonist GR117289C on the contraction induced by AII and other vasoconstrictors in isolated human internal mammary artery (IMA) preparations.

METHODS

Two hundred eight IMA rings taken from 64 patients undergoing coronary artery bypass grafting were studied in organ baths. The interaction between GR117289C and AII or the other vasoconstrictors (U46619, norepinephrine, endothelin-1, and potassium chloride) was investigated in two ways.

RESULTS

GR117289C induced near-maximal relaxation (94.5% +/- 2.9%) in IMA rings precontracted by AII. In IMA rings incubated with 1 or 10 nmol/L GR117289C, contractile responses to AII were attenuated in a concentration-related manner, whereas the dose-response curve did not shift to the right when higher doses of AII were administered, suggesting that the AT1 receptor blockade was noncompetitive in nature. Moreover, GR117289C also induced significant relaxation (82.9% +/- 8.1%) in IMA rings precontracted by U46619, but no inhibitory responses to U46619 could be observed when IMA rings were incubated with GR117289C. GR117289C did not alter responses to potassium chloride, norepinephrine, and endothelin-1.

CONCLUSIONS

These results indicate that GR117289C is a potent, selective, noncompetitive AT1 receptor antagonist that may have a possible antagonistic effect on the thromboxane A2 receptor. Because AII and thromboxane A2 are important vasoconstrictors in the genesis of graft spasm, GR117289C may become an alternative treatment to relieve graft spasm.

Spontaneous formation of polypeptides in the interfacial thin films of amphiphilic amino acid esters: acceleration of the polycondensation and control of the structure of resultant polymers

For the purpose of elucidating the effects of molecular arrangements on the reaction rates and the structure of products, polycondensation of long-chain esters of alpha-amino acids in the monolayer on the water surface and the LB multilayers deposited on CaF2 plates were investigated by monitoring changes of the IR spectra. Spontaneous formation of the polypeptides occurs in the mono- and multilayers at room temperature without any catalyst. The rates of polycondensation in the monolayers are markedly influenced by the degree of molecular packing. Maximum polymerizability is obtained in the vicinity of the transition region from expanded to condensed films. The rates of polycondensation in the LB films are much higher than those in the bulk solids and the molten states. The polycondensation seems to be accelerated by regular arrangements of the monomer molecules in the LB films, where the functional groups are concentrated and situated more effectively for the reaction than in the bulk states. However, the polycondensation rates in the LB films are considerably slower when compared with those in the monolayers on the water surface kept at the optimum area or surface pressure, because the molecules in the LB films deposited under high compression are packed more closely than the optimum condition. Thus, suitably close packing of the monomer molecules, retaining a particular orientation together with some conformational freedom in the monolayer, is most favorable for the polycondensation. Two probable mechanisms for the polycondensation in the Y-type multilayers have been proposed. In the assembly of head-to-head double layers of the monomer molecules, the interlayer reaction propagates by sewing up the functional groups facing each other in the adjacent layers, and the polypeptide of a helical structure or random coil can be obtained. In contrast, for the alternating assembly of the amino acid ester and non-polymerizable octadecyl acetate, the polycondensation should proceed only in each single layer (intralayer reaction) and the polypeptide of the extended beta-form can be formed. In the case of dioctadecyl glutamate LB films, as well as the monolayer on water, the resultant polypeptide is the comb-like polymer with unreacted long-alkyl ester groups as side chains and abundant in the beta-form, indicating the dominant intralayer reaction. On the other hand, in the Y-type multilayer of the equimolar mixture of dioctadecyl glutamate (with two ester groups) and octadecyl ester of lysine (with two amino groups), both of the intra- and interlayer reactions occur effectively, resulting in a two-dimensional network structure of the polypeptide. In conclusion, not only the rate of polycondensation but also the higher-order structure of the resultant polypeptides can be controlled by organized arrangements of the monomer molecules in the interfacial thin films.

Transcutaneous oxygen tension in subjects with tetraplegia with and without pressure ulcers: a preliminary report

This study compared transcutaneous oxygen tension (TcpO2) in subjects with paraplegia and pressure ulcers (PU), those with paraplegia and no pressure ulcer (NPU), and ambulatory controls. TcpO2 was measured using a surface-electrode monitoring system, recorded at 1-min intervals for 5 min and averaged. Mean TcpO2 was significantly lower in the PU than the NPU and control groups (23.53+/-1.83 vs. 58.93+/-2.53 and 79.70+/-6.77 mmHg, respectively, p<0.05). In a PU subgroup (n=4) mean TcpO2 of the pressure ulcer and nonpressure ulcer sides (trochanter or ischium) were significantly different (21.05+/-2.98 vs. 67.65+/-2.11 mmHg, respectively, p<0.001). Additionally, the NPU group demonstrated significantly lower TcpO2 than the controls. PUs had a greater reduction in TcpO2 levels relative to controls than NPUs. No association was found between TcpO2 and duration of injury, completeness of lesion, or smoking history. Thus, TcpO2 may be an effective method to identify individuals who are susceptible to pressure ulcers. The further attenuation of TcpO2 observed in the PU group may be useful to help predict whether ulcers will heal with local care or will require additional treatment.

Increased energy needs in patients with quadriplegia and pressure ulcers

Health individuals with quadriplegia generally have a reduced metabolic rate. However, individuals with quadriplegia who develop pressure ulcers may have an elevated metabolic rate. In this study, energy expenditure in 16 individuals with quadriplegia and pressure ulcers (PU-QUAD) was compared to the energy expenditure in 16 individuals with quadriplegia but no pressure ulcers (NPU-QUAD) and 16 healthy non-spinal cord injured subjects (controls). Resting energy expenditure (REE) was measured by indirect calorimetry. Both measured REE (t(30) = 2.38, p = 0.24) and percent predicted REE (t(30) = 3.23, p = .003) were significantly higher in subjects with quadriplegia and pressure ulcers compared with subjects with quadriplegia but no pressure ulcers. On average, REE in the PU-QUAD subjects was nearly equal to the absolute energy expenditure of healthy non-spinal cord injured controls. To ensure optimal care of patients with quadriplegia and pressure ulcers, quantification of energy expenditure with provision of adequate caloric intake is recommended.

Resting metabolic rate in subjects with paraplegia: the effect of pressure sores

OBJECTIVE

To determine the overall effect of paraplegia and pressure sores on resting metabolic rate.

DESIGN

Unblinded, case-control study using a convenience sample.

SETTING

Hospital primary care setting.

PATIENTS

Fourteen individuals with paraplegia and pressure sores (PS-Para), 24 with paraplegia in good health (NPS-Para), and 23 non-spinal cord injury (SCI) controls.

MAIN OUTCOME MEASURES

The planned outcome measures consisted of resting metabolic rate, percent of predicted resting metabolic rate, resting metabolic rate per kilogram body weight, and resting metabolic rate per meter squared body surface area. Post hoc analyses were used to identify the effect of completeness of lesion, smoking, and pressure sores on percent of predicted resting metabolic rate and resting metabolic rate per kilogram body weight.

RESULTS

Percent of predicted resting metabolic rate and resting metabolic rate per kilogram body weight were significantly higher in the PS-Para group than in the NPS-Para or control groups (115% +/- 4% vs 100% +/- 2% or 107% +/- 2%, p < .05) and (25.9 +/- 1.2 vs 21.4 +/- 0.6 or 22.5 +/- 0.4 kcal/kg, p < .05, respectively). The resting metabolic rate per meter squared body surface area was significantly higher in the PS-Para group than in NPS-Para group (973 +/- 39 vs 874 +/- 20kcal/m2, p < .05). In the PS-Para group, current smokers had significantly higher resting metabolic rate per kilogram body weight than nonsmokers (27.3 +/- 1.7 vs 24.0 +/- 1.4kcal/kg, p < .01). Controlling for the effects of smoking in a multiple regression model, those in the PS-Para group had significantly (p < .001) greater percent of predicted resting metabolic rate and resting metabolic rate per kilogram body weight than those in the NPS-Para group.

CONCLUSIONS

These findings indicate that individuals with SCI may have a decreased percent of predicted resting metabolic rate and those with pressure sores may have a hypermetabolic state. This hypermetabolic state is significantly higher than that resulting from smoking. Because ordinary prediction equations for energy expenditure may not be accurate when applied to subjects with paraplegia and pressure sores, quantification of energy needs by indirect calorimetry is recommended.

The value of ultrasound measurement of gallbladder wall thickness in predicting laparoscopic operability prior to cholecystectomy

We prospectively analysed 51 consecutive cases who underwent laparoscopic cholecystectomy from June 1992 to February 1993. There were 35 cases of chronic cholecystitis and 16 cases of acute cholecystitis. All underwent pre-operative ultrasonography, complete blood cell count, liver function test and endoscopic retrograde cholangiopancreatography. Of those 44 had post-operative ultrasound within the first 2 d and again on the seventh day. In 35 cases of chronic cholecystitis, 31 of 32 cases with a pre-operative gallbladder (GB) wall thickness of less than 6 mm were successfully resected laparoscopically. All three cases with a GB wall thicker than 6 mm were converted to open cholecystectomy. In acute cholecystitis, the wall thickness of the laparoscopic cholecystectomy group ranged from 2 to 9 mm (average 4 mm) and the wall thickness of the conversion group was 4-7 mm (average 6 mm). Post-operative fluid accumulation was noted in 28 (63.6%) cases. There was no correlation between post-operative pyrexia, duration of post-operative pain, clinical complications and the presence of fluid accumulation in the GB fossa. However, of four cases with increasing fluid on the seventh day, three developed complications. We conclude that ultrasonography is valuable in chronic cholecystitis for selecting cases for laparoscopic cholecystectomy.

Insulin-associated changes in carnitine palmitoyltransferase in cultured neonatal rat cardiac myocytes

Insulin increases the synthesis of mitochondrial proteins in the isolated perfused heart and total cell protein synthesis in neonatal cardiac myocytes. Since carnitine-dependent fatty acid oxidation is modulated by insulin in a variety of tissues, the effects of 1.7 microM insulin on the mitochondrial enzyme(s), carnitine palmitoyltransferase (malonyl-CoA-sensitive CPT-I and the matrix-facing CPT-II), were studied in neonatal rat cardiac myocytes cultured in the absence of serum. Following incubation in serum-free medium, there is a four-fold increase in the I50 of CPT-I for malonyl-CoA (3.8 microM) compared to cells cultured in serum-free medium to which insulin has been added (I50 = 0.8 microM). CPT-I activity in the insulin-supplemented, serum-free cultures is 57% higher (P < 0.002) than CPT-I activity in cells cultured in the absence of insulin; CPT-II activity is also significantly increased (P < 0.01) in the presence of insulin. Since CPT-II is an inner membrane protein, the CPT response to insulin may be coordinately regulated with other mitochondrial activities. Similar to CPT, cytochrome oxidase activity of cardiac myocytes in serum-free medium is increased 33% by insulin. Consistent with this finding, both CPT-II and cytochrome oxidase mRNA expression is elevated over control in the presence of insulin. CPT-II activity increases significantly only at very high insulin concentrations (1.7 microM), suggesting a role for insulin-like growth factor pathway. When myocytes are cultured in the presence of 1.7 microM insulin and then transferred to an insulin-free medium, subsequent addition of insulin does not stimulate uptake of deoxyglucose. These results suggest that the response of CPT to insulin is mediated by insulin-like growth factor activity and not by cellular glucose availability. The response of CPT to insulin does not appear to be mediated by the protein kinase C pathway since CPT-II activity is not reduced by the protein kinase C inhibitor, chelerythrine. Insulin significantly increases protein synthesis in the neonatal cardiac myocyte and in isolated mitochondria by increasing incorporation of labelled amino acid into total myocyte and/or mitochondrial protein. The degradation rate of radiolabelled protein in cardiac myocytes cultured in the presence of insulin is not different from that of insulin-deprived cells. The data suggest that insulin can affect the activity and expression of mitochondrial proteins, e.g., CPT, through the insulin-like growth factor-I pathway in neonatal cardiac myocytes.

Myocardial protection of cold crystalloid and warm blood cardioplegia. A comparative study

Twenty patients undergoing open-heart valvular operations were divided randomly into two groups. Intermittent perfusion of cold crystalloid (St. Thomas Hospital solution) with hypothermic cardiopulmonary bypass (CPB) in the hypothermic group and continuous administration of warm blood cardioplegia with normothermic CPB in the normothermic group were used respectively. The results of warm blood cardioplegia were superior to those of cold crystalloid. 70% of patients treated with the warm technique had spontaneous return of normal sinus rhythm shortly after removal of the aortic cross-clamp, compared with only 10% of the hypothermic group (P < 0.05). The extracorporeal support time from releasing of aortic clamp to the weaning of CPB was significantly shorter in the normothermic group (33.50 +/- 3.78 min vs. 25.00 +/- 4.64 min, P < 0.05). The postoperative ventilation support time was also much shorter than that of the hypothermic group (19.84 +/- 1.11 h vs. 38.98 +/- 16.55 h, P < 0.05). More atrial beating occurred in the normothermic group (80% vs. 20%, P < 0.05) during aortic clamping, and it is showed that continuous warm blood cardioplegia might not efficiently prevent the atrium from damage.

Human RNaseP RNA and nucleolar 7-2 RNA share conserved 'To' antigen-binding domains

RNase P in both prokaryotes and eukaryotes is a ribonucleoprotein that cleaves tRNA precursors to generate the 5' termini of the mature tRNAs. Many patients with autoimmune diseases produce antibodies against a 40 kDa protein (designated To or Th antigen) which is an integral component of eukaryotic RNaseP as well as nucleolar 7-2 RNP which is identical to the mitochondrial RNA processing (MRP) RNP. Interestingly, the To antigen found in human cells and the C5 protein, the only protein component of E. coli RNaseP, are antigenically related. In this study, we show that a 56 nucleotide-long sequence, corresponding to nucleotides 20-75 near the 5' end of human RNaseP RNA, is sufficient to bind the To antigen. We previously showed that the human To antigen binds to a short distinct structural domain near the 5' end of human 7-2/MRP RNA. There is no obvious primary sequence homology between the To antigen binding sites in RNaseP RNA and 7-2/MRP RNA; however, these sequences are capable of assuming a similar secondary structure which corresponds to the recently proposed 'cage' structure for RNaseP RNAs and 7-2/MRP RNA (Forster and Altman (1989) Cell 62: 407-409). These data are supportive of the idea that these two RNAs may have evolved from a common progenitor molecule.

Mutation analysis of K-ras oncogenes in gastroenterologic cancers by the amplified created restriction sites method

A rapid, simple, and nonradioactive method for diagnosing point mutations of c-K-ras oncogenes in gastroenterologic cancers is described. This method involved the selective amplification of DNA fragments from cancer tissues of surgical specimens with specific oligonucleotide primers, followed by digestion with restriction enzymes that recognized artificially created or naturally occurring restriction sites. To detect codon 12 mutations, an artificial Msp I site was created by introducing a single nucleotide mismatch into the 5' mutagenesis primer. Using a similar approach, an Hae III site was created to detect codon 13 mutations. Bal I and MBo II sites were used to detect codon 61 mutations. A total of 61 gastroenterologic cancer cases were studied. Of 35 cases of colorectal cancer, 7 showed mutations: 6 at codon 12 and 1 at codon 13. In 1 of 2 cases of cholangiocellular carcinoma, point mutation at codon 12 was found. One case of duodenal cancer showed point mutation at codon 12. No mutations were found in the cases of hepatocellular carcinoma (4), gastric cancer (12), esophageal cancer (3), or pancreatic cancer (2).

Distribution of glucose-6-phosphatase activity in normal, hyperplastic, and preneoplastic rat liver

The significance of glucose-6-phosphatase (G6P) expression by bile duct-like cells proliferating during hepatocarcinogenesis in the histogenesis of hepatocellular carcinoma is not clear. To this end, we measured the histochemical and biochemical activity of G6P in normal rat liver, and in rat livers in which bile duct-like proliferation was induced by either hyperplastic (bile duct ligation for 14 days or feeding alpha-naphthylisothiocyanate for 28 days) or neoplastic (feeding a choline-devoid diet containing 0.1% ethionine for 60 days) regimens. In normal, hyperplastic, and preneoplastic livers, G6P histochemical activity was confined to the hepatocytes; proliferated bile duct-like cells, like normal bile ducts, did not display visible G6P staining. When the enzyme activity was determined biochemically, however, hydrolysis of glucose-6-phosphate was observed in both parenchymal and nonparenchymal liver cells isolated from all experimental animals. In elutriated nonparenchymal fractions, G6P activity was directly proportional to the number of cells positive for gamma-glutamyl transpeptidase and cytokeratin no. 19 (markers of bile duct cells) and inversely proportional to the number of cells positive for vimentin (marker of mesenchymal cells). These results indicate that, while by light microscopy hepatic G6P histochemical activity is detectable only in the hepatocytes, the biochemical activity is also expressed in proliferating bile duct-like cells. However, the nonparenchymal activity is observed during both neoplastic and hyperplastic liver growth, thus indicating that the presence of this enzyme in bile duct-like cells proliferating during hepatocarcinogenesis should not necessarily be construed as supporting their stem cell nature nor their neoplastic commitment.

Characterization of antibodies against methyl-pppN cap structure: plant U3 small nucleolar RNA is recognized by these antibodies

In eukaryotes, many small nuclear RNAs contain either a trimethylguanosine cap structure of a gamma-monomethyl (me) cap structure. Previously, we reported the characterization of anti-mepppG antibodies which recognize methyl-capped RNAs with G as the initiation nucleotide. We report here the preparation of antibodies against mepppN cap structure. Anti-mepppN antibodies recognized only mepppN from a mixture of mepppN and pppN and immunoprecipitated mepppA-capped U3 small nucleolar RNA from a mixture of cowpea cell RNAs. These anti-mepppN antibodies recognized methylated nucleoside triphosphates (mepppA, mepppC, mepppG and mepppU) with nearly equal efficiency; however, these antibodies did not recognize methyl phosphate or methylated mononucleotides. These antibodies will be useful in the identification and characterization of all methyl-capped RNAs no matter which is the initiation nucleotide.

Histogenesis of bile duct-like cells proliferating during ethionine hepatocarcinogenesis. Evidence for a biliary epithelial nature of oval cells

The origin of bile duct-like cells (oval cells) proliferating during chemical hepatocarcinogenesis is highly controversial. To illuminate this issue, we induced oval cell proliferation by feeding rats a choline-devoid diet containing 0.1% ethionine (CDE), a hepatocarcinogenic diet, for up to 60 days. At various times we studied 1) oval cell morphology by light and electron microscopy, 2) the immunohistochemical expression of albumin and intermediate filament proteins by the various hepatic cells, 3) hepatic incorporation of [3H]thymidine by histoautoradiography, 4) the fractional area occupied by duct-like structures in liver cross sections, 5) the biliary tree volume in vivo to establish the possible continuity of the proliferated structures to the existing biliary lumina, and 6) spontaneous bile flow rate and the choleretic responsiveness to the hormone secretin, which stimulates ductular secretory activity. The results demonstrated the following: 1) oval cells resemble bile duct cells with respect to their histologic and ultrastructural appearance and their formation of duct-like structures; 2) as normal and hyperplastic bile duct cells induced by bile duct ligation, oval cells are positive for cytokeratins 7 and 19 (markers of glandular epithelia) and 8 and 18 (markers of simple epithelia) and are negative for vimentin and desmin, markers of mesenchymal and muscular differentiation, respectively; 3) in general, oval cells are negative for albumin, which is expressive of hepatocyte lineage, even though a few are positive for this protein, particularly those morphologically resembling small hepatocytes; 4) after initiation of the CDE diet, DNA synthesis begins in biliary epithelial cells; and 5) the degree of oval cell proliferation parallels the increase in biliary tree volume, spontaneous bile flow rate, and responsiveness to secretin choleresis, as in bile duct cell hyperplasia induced by biliary obstruction. Although the involvement of a periductular progenitor compartment cannot entirely be eliminated, these findings are construed to indicate that oval cells proliferating during CDE hepatocarcinogenesis are biliary epithelial cells. In our view, oval cells represent the two-dimensional expression of spatially expanded cholangioles and intrahepatic bile ductules and/or ducts.

von Willebrand factor antigen is not an accurate marker of rat and guinea pig liver endothelial cells

To determine whether von Willebrand Factor (vWF) is a valid marker of liver endothelial cells, we determined vWF immunoreactivity in rat and guinea pig liver sections and in smears of elutriated nonparenchymal cells isolated from these two species. In frozen sections, positive staining for vWF was seen only in the endothelium lining large hepatic vessels in both species, and no immunoactivity was detected in the sinusoids. On the other hand, immunohistochemical staining for vimentin (a marker of mesenchymal cells) showed positive reaction throughout the vascular and sinusoidal endothelial cells in both the rat and guinea pig liver. In fractions of elutriated rat and guinea pig nonparenchymal liver cells, which included almost exclusively liver endothelial cells, only 25-40% of the cells displayed a positive reaction for vWF. However, when these same fractions were stained for vimentin, 70-95% of the cells exhibited immunoreactivity. Most of the vWF-negative cells were not red and white blood cells, biliary epithelial and Kupffer cells, and hepatocytes, and had ultrastructural features of sinusoidal endothelial cells. We conclude that in both the rat and guinea pig, liver sinusoidal endothelial cells do not exhibit vWF immunoreactivity. Thus, in routine immunohistochemical assays, vWF is not an accurate marker of rat and guinea pig liver endothelial cells. Vimentin is more appropriate for this purpose, provided that other mesenchymal cells are separated or independently identified.

Origin, pattern, and mechanism of bile duct proliferation following biliary obstruction in the rat

Proliferation of bile duct-like structures is a hepatic cellular reaction observed in most forms of human liver disease and in a variety of experimental conditions associated with liver injury. Yet the origin, means of initiation, and significance of this hyperplasia are unknown. To clarify these issues we induced bile duct proliferation in rats by ligating the common bile duct and studied (a) hepatic incorporation of [3H]thymidine by histoautoradiography, (b) hepatic morphometry, (c) biliary tree volume using [3H]taurocholate as a marker of biliary transit time, (d) immunohistochemical expression of cytokeratin no. 19, (e) the effect of indomethacin, and (f) the role of increased biliary pressure, in the absence of physiological and biochemical evidence of cholestasis, on [3H]thymidine incorporation by the bile-duct cells. The results have demonstrated that (a) the proliferating bile duct-like cells are products of the extant biliary epithelium and retain its characteristics; (b) bile duct cells divide irrespective of the size of the duct in which they are located and form a system with a lumen continuous with the preexisting one; (c) bile duct proliferation results mainly in elongation, not in circumferential enlargement or sprouting of side branches; (d) portal macrophage infiltration does not play a role in the hyperplastic reaction, and (e) increased biliary pressure is the initiating factor in bile duct cell division. Our results provide evidence that under the present conditions, ductular metaplasia of hepatocytes does not occur and there is no functioning stem cell for biliary epithelial growth segregated in any particular duct size or within the portal connective tissue.

Occupational risk factors for gastric cancer in Shanghai, China

Occupational data for over 13,000 incident stomach cancer cases reported to the Shanghai Cancer Registry between 1980 and 1984 were compared with 1982 census employment information to calculate standardized incidence ratios for stomach cancer in the Shanghai urban area. Several occupations were found to have statistically significantly increased risks for stomach cancer, most notably grain farming and several jobs involving potential for exposure to metal, wood, and other dusts and to fossil fuel combustion products. Because of the large numbers involved and consistency of associations, the findings raise hypotheses regarding occupational exposures that warrant further investigation.

Isolation of a nonparenchymal liver cell fraction enriched in cells with biliary epithelial phenotypes

In the present study we have isolated and purified fractions of nonparenchymal liver cells were isolated by collagenase-pronase digestion of the biliary and connective hepatic tissue, which remained undissociated after collagenase perfusion of the liver. Fractionation of the nonparenchymal fractions was then achieved by centrifugal elutriation. Both normal rats and rats with proliferated bile duct-like structures, which were induced either by a 14-day bile duct ligation or by feeding 0.1% alpha-naphthylisothiocyanate for 28 days, were used in these studies. Using a normal rat liver, the fraction richest in biliary epithelial cells was that obtained at a pump flow rate of 36-40 ml/min. In this fraction 1.8-3.8 x 10(6) cells per liver were recovered and up to 55% of them were positive for gamma-glutamyl transpeptidase and cytokeratins 7 and 19, all of which were histochemically or immunohistochemically detected solely in the biliary structures in the intact rat liver. When the nonparenchymal cells were isolated from hyperplastic livers, the number of cells recovered in such a fraction ranged from 12 to 19 x 10(6) per liver, and as many as 60%-85% of the cells expressed phenotypes of biliary epithelial cells. These results indicate that (a) by centrifugal elutriation a fraction of nonparenchymal cells enriched in cells with biliary epithelial phenotypes can be obtained from rat liver and (b) the hepatic hyperplasia induced by biliary obstruction or alpha- naphthylisothiocyanate feeding is a useful and valid strategy for improving both the yield and the purity of the isolated biliary epithelial cells.

Bile secretory function of intrahepatic biliary epithelium in the rat

To shed light on ductular fluid secretion, hepatic histology and ultrastructure, cell proliferation and phenotypes, and several aspects of biliary physiology were studied in rats with ductular cell hyperplasia induced by either biliary obstruction (0-14 days) or 1-naphthylisothiocyanate (ANIT) feeding (0-28 days). In both groups of experimental animals, bile duct hyperplasia and spontaneous bile flow and secretin-induced choleresis increased with time of treatment in a linear fashion. Measurements of [14C]mannitol biliary entry and of biliary tree volume showed that the increase in both spontaneous and secretin-stimulated bile flow originated at the proliferated biliary structures. Ultrastructural examination, [3H]thymidine incorporation, and histochemical and immunohistochemical staining for various markers demonstrated that in both hyperplastic reactions the proliferated cells were the progeny of preexisting biliary epithelial cells and retained their characteristics. These results indicate that the increased bile secretory activity associated with either biliary obstruction or ANIT intoxication reflects a quantitative change due to the proliferation of biliary epithelial cells. Thus both models of bile ductular cell hyperplasia lend themselves to assessment of the transport function of intrahepatic biliary epithelium and its contribution to normal bile formation. In the present studies, we have estimated that net ductular secretion in the normal rat accounts for 10-13% of spontaneously secreted hepatic bile.

Identification and characterization of a polyadenylated small RNA (s-poly A+ RNA) in dinoflagellates

A 104 nucleotide-long small RNA, referred to as s-poly A+ RNA, containing 30 adenosine residues on its 3' -end was found in dinoflagellates, purified and its nucleotide sequence was determined. The sequence is: (sequence text) The polyadenylation signal AAUAAA was not found in this RNA; this result indicates that the 30 nucleotide-long poly A on the 3' -end is either coded for by this gene, or the poly A chain is added on this small RNA by a mechanism different from that for polyadenylation of messenger RNAs. Two polyadenylated small RNAs identified previously were implicated in differentiation of chicken heart muscle cells (Deshpande, A. K., Jakowlew, S. B., Arnold, H., Crawford, P. A. and Siddiqui, M. A. Q. (1977) J. Biol. Chem. 252, 6521-6527), and in brain specific mRNA transcription (Sutcliffe, J. G., Milner, R. J., Gottesfeld, J. M. and Lerner, R. A. (1984) Nature 309, 237-241). This RNA is the first polyadenylated small RNA to be sequenced.

Cholangiocarcinoma in hepatolithiasis

During the period of 1979-1982, 10 cases of cholangiocarcinoma associated with hepatolithiasis were seen. We report the clinical features of 10 cases of cholangiocarcinoma in association with hepatolithiasis, along with detailed histopathology from the four resected specimens. Our observations suggest that whenever intrahepatic stones are encountered in patients over 50 years of age with a long history of recurrent cholangitis and intractable pain, further examination including echo-guided aspiration cytology, liver scanning, and peritoneoscopy should be performed to rule out a coexisting cholangiocarcinoma.

Primary and secondary structure of dinoflagellate U5 small nuclear RNA

U5 RNA is one of the six capped small nuclear RNAs present in most eukaryotic cells. Like U1, U2, U4 and U6 RNAs, U5 RNA is associated with hnRNP particles and is thus probably involved in some, as yet undefined, aspects of pre-messenger RNA processing. In this study, the complete nucleotide sequence of U5 RNA of a dinoflagellate, Crypthecodinium cohnii was determined. The analysis of this dinoflagellate U5 RNA sequence showed that a) the sequence homology between human, rat and chicken U5 RNA sequences and dinoflagellate U5 RNA sequence is 64%; b) the extent and the position of post-transcriptional modifications are similar to those found in U5 RNA of higher eukaryotes; c) although the dinoflagellate U5 RNA is shorter in length (108 nucleotides long vs 117 long in human, rat and chicken cells), the RNA fits well into the same secondary structure proposed for U5 RNA of higher eukaryotes (Krol et al. (1981) Nucl. Acids Res. 9, 769); and d) the AUn nucleotide sequence protected by the Sm-antigen and the tight secondary structure found near the 3'-end of other U-RNAs was also found in dinoflagellate U5 RNA. The high order of homology observed between dinoflagellate U5 RNA and U5 RNA of higher eukaryotes indicates that dinoflagellates are more closely related to metazoans than to early eukaryotes.

Isolation and partial characterization of dinoflagellate U1-U6 small RNAs homologous to rat U small nuclear RNAs

The dinoflagellates are a group of diverse eukaryotic algae possessing a number of unique cellular properties. Evidence is presented for the presence of six capped small nuclear RNAs in these dinoflagellates. By several criteria such as the (a) presence of trimethylguanosine cap structure in U1 to U5 RNAs, (b) sequence homology between rat and dinoflagellate U2, U5 and U6 RNAs, (c) presence of other post-transcriptional modifications such as sugar and base modifications, and (d) association of Sm antigen with five of these six RNAs, the six RNAs of dinoflagellates appear to be similar to the well characterized U1 to U6 RNAs found in higher eukaryotes. This is the first demonstration of antigenic small nuclear RNA-containing particles in any unicellular organism. These results suggest that the U1 to U6 RNAs and the associated Sm antigen evolved at a very early stage of eukaryotic evolution. With respect to U small nuclear RNAs and their associated proteins, the dinoflagellates appear to exhibit eukaryotic characteristics.

The nucleotide sequence of 8 S RNA bound to preribosomal RNA of Novikoff hepatoma. The 5'-end of 8 S RNA is 5.8 S RNA

8 S RNA of Novikoff hepatoma was characterized by fingerprinting, sequencing gels, and by hybridization to rat ribosomal DNA clones. The data obtained show that 8 S RNA is 273 or 274 nucleotides long; ribosomal 5.8 S RNA is its 5'-terminal 156 nucleotides. All the post-transcriptional modifications found in 5.8 S rRNA were also found in 8 S RNA; no other modifications were found. The 3'-terminal 118 nucleotides were consistent with the adjoining internal transcribed spacer sequence in rDNA (Subrahmanyam, C. S., Cassidy, B., Busch, H., and Rothblum, L. (1982) Nucleic Acids Res. 10, 3667-3680). Based on its nucleolar localization, the finding that all the 8 S RNA is hydrogen-bonded to preribosomal RNA and its consistency in sequence to the cloned rat ribosomal DNA sequence, it appears that 8 S RNA is a relatively stable intermediate in the formation of 5.8 S rRNA from 45 S pre-rRNA. This stable intermediate RNA may be a useful substrate for studies on rRNA processing and for studies on eukaryotic rRNA-processing enzyme(s).