Autophagy deficiency in beta cells leads to compromised unfolded protein response and progression from obesity to diabetes in mice

AIMS/HYPOTHESIS

The unfolded protein response (UPR) in endoplasmic reticulum (ER) and autophagy are known to be related. We investigated the role of autophagy in UPR of pancreatic beta cells and the susceptibility of autophagy-deficient beta cells to the ER stress that is implicated in the development of diabetes.

METHODS

Rat insulin promoter (RIP)-Cre(+);autophagy-related 7 (Atg7)(F/W) mice were bred with ob/w mice to derive RIP-Cre(+);Atg7(F/F)-ob/ob mice and to induce ER stress in vivo. GFP-LC3(+)-ob/ob mice were generated to examine in vivo autophagic activity. Real-time RT-PCR was performed to study the expression of the genes of the UPR machinery. Proteolysis was assessed by determining release of incorporated radioactive leucine.

RESULTS

Production of UPR machinery was reduced in autophagy-deficient beta cells, which was associated with diminished production of p85α and p85β regulatory subunits of phosphoinositide 3-kinase. Because of compromised UPR machinery, autophagy-deficient beta cells were susceptible to ER stressors in vitro. When mice with beta cell-specific autophagy deficiency, which have mild hyperglycaemia, were bred with ob/ob mice to induce ER stress in vivo, severe diabetes developed, which was accompanied by an increase in beta cell death and accumulation of reactive oxygen species. The increased demand for UPR present in obesity was unmet in autophagy-deficient beta cells. Autophagy level and autophagic activity were enhanced by lipid, while proteolysis was reduced.

CONCLUSIONS/INTERPRETATION

These results suggest that autophagy is important for intact UPR machinery and appropriate UPR in response to lipid injury that increases demand for UPR. Autophagy deficiency in pancreatic beta cells may contribute to the progression from obesity to diabetes.

Preoperative anxiety and pain sensitivity are independent predictors of propofol and sevoflurane requirements in general anaesthesia

BACKGROUND

Psychological factors are thought to drive inter-patient variations in anaesthetic and analgesic requirements. This cross-sectional study investigated whether preoperative psychological factors can predict anaesthetic requirements and postoperative pain.

METHODS

Before total thyroidectomy, 100 consecutive women completed the Spielberger's State-Trait Anxiety Inventory (STAI) and the pain sensitivity questionnaire (PSQ). Target-controlled propofol was administered for induction of anaesthesia, and sevoflurane-oxygen-air was given to maintain equal depths of anaesthesia, as determined by bispectral index (BIS) monitoring.

RESULTS

Patients with higher anxiety scores (state and trait) required greater amounts of propofol to reach light (BIS=85) and moderate (BIS=75) levels of sedation, but only trait anxiety was significantly associated with propofol requirements in reaching a deep level of sedation (BIS=65). The MAC-hour of sevoflurane was significantly correlated only with PSQ scores. The postoperative pain intensity was significantly correlated with both STAI and PSQ.

CONCLUSIONS

Preoperative anxiety and pain sensitivity are independent predictors of propofol and sevoflurane requirements in general anaesthesia. Anaesthetic and analgesic doses could be modified based on the patient's preoperative anxiety and pain sensitivity.

Endoscopic submucosal resection of esophageal subepithelial lesions using band ligation

Subepithelial lesions (SELs) are occasionally found in the esophagus during upper endoscopy. Sometimes endoscopic resection is needed for accurate diagnosis or in the rare cases of malignant transformation of SELs. In this case series, we evaluated the usefulness of endoscopic submucosal resection with a ligation device (ESMR-L) in esophageal SELs. Twenty-three patients with 25 esophageal SELs that were no larger than 13 mm and were localized within the muscularis mucosae or submucosa were enrolled. ESMR-L was successfully performed in all 25 SELs. The en bloc resection rate was 100% (25/25), and histologically complete resection was achieved in 24 lesions (24/25, 96%). After resection of the lesion by snare, minor immediate bleeding occurred in four cases, but there was no delayed bleeding or perforation.

Abstract 3839: Wild-type p53 induced protein phosphatase (Wip1) inhibits the proapoptotic function of JNK and p38 MAPK in prostate cancer cells

The mechanism regulating radiation-induced anti-apoptotic response in prostate cancer cell lines is not clear yet. Wip1 is the major member of the Ser/Thr PP2C family that dephosphorylates and inactivates p38 MAPK, p53, chk1, Mdm2 and ATM. Here we provide Wip1 was negative regulator of γ-radiation-mediated apoptotic response in LNCaP cells. The levels of Wip1 were increased after exposed to γ-radiation and induced Wip1 repressed cell death. Wip1 depletion with siRNA resulted in increased apoptotic cell death in LNCaP cells, which was not observed in radiation-sensitive HeLa cells. Radiation-induced Wip1 induction was inversely co-related with the decrease of phospho-JNK and -p38 MAPK in LNCaP cells, indicating that Wip1 is a negative regulator of JNK and p38 MAPK pathways. Furthermore, in response to γ-radiation, Bax proteins are increased and directly interact with Wip1. The data suggest that Wip1 may be a central player on the mechanism of radio-resistance in LNCaP cells. Currently, we are investigating the role of Wip1 in BAX-mediated apoptotic cell death.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3839. doi:10.1158/1538-7445.AM2011-3839

A case of a giant mucocoele of the appendiceal stump presented with a palpable mass in the right thigh: pre-operative diagnosis based on characteristic multidetector CT findings

The pre-operative diagnosis of a mucocoele of the appendiceal stump (MAS) may be difficult owing to rarity and non-specific clinical presentation. However, a pre-operative diagnosis of a MAS is important to prevent widespread dissemination by inadvertent spillage of mucous contents. We describe a case of a MAS presenting with a palpable mass in the right thigh in which a pre-operative diagnosis was made by characteristic multidetector CT (MDCT) findings.

Improvement of transmittance by fabricating broadband subwavelength anti-reflection structures for polycarbonate

We report on how to increase transmittance of a 0.2 mm thick polycarbonate (PC) film by periodic subwavelength anti-reflection structures in the visible spectral range. Subwavelength anti-reflection structures like moth-eyes are fabricated into the polycarbonate substrate itself by thermal nano-imprinting lithography (TH-NIL), which uses silicon stamps that have periodic structures such as gratings (lines and spaces) and pillared dots, and are fabricated by laser interference lithography (LIL) and transformer coupled plasma etching. To increase transmittance of a polycarbonate film, we control the periods and shapes of patterns, the number of patterned surfaces, and the overlapping direction of patterns that are fabricated into its surfaces. As a result of this, we show that average transmittance improves as the pattern period gets shorter and as both surfaces of the film are patterned. We also show that the spectrum range gets larger as the pattern period gets shorter and is determined by the longer pattern period in the case of designing a film to have different pattern period on its surfaces. The maximum average transmittance of a polycarbonate film increases up to approximately 6% compared to a bare sample in the 470-800 nm spectral range.

Does propofol and alfentanil-induced sedation cause periodic apnoea in chronic renal failure patients?

AIMS

There is evidence suggesting that the respiratory response to sedation is different in patients with sleep apnoea, which is common in patients with chronic renal failure (CRF). This study examined the respiratory response of sedation with propofol and alfentanil, whose pharmacokinetics are not affected by the renal function, in CRF patients.

METHODS

Chronic renal failure patients who underwent arteriovenous-fistular surgery (CRF group) and patients who underwent chemoport insertion (control group) were enrolled in this study. Sedation was induced by infusing propofol 1.5 micro/ml and alfentanil 0.2 micro/kg/min continuously in both groups. In the desaturation study, the respiratory rate and peripheral oxygen saturation in room air were checked. In the apnoea-hypopnoea study, the patient's sedation (Observer's Assessment of Alertness/Sedation) score, apnoea-hypopnoea index (AHI) was recorded using a portable ventilation effort recorder (microMesam) while applying 5 l/min of oxygen through a facial mask.

RESULTS

The desaturation event was more common (21.5/h vs. 2/h, p = 0.001) in the CRF patients. Apnoea and hypopnoea (AHI: 13.0 vs. 1.6, p = 0.012, per cent of patients with an AHI > 5: 53.3% vs. 7.1%, p = 0.014) occurred more frequently in the CRF patients but the sedation score was not different.

CONCLUSION

Chronic renal failure patients have a higher risk of developing apnoea and hypopnoea during sedation, which highlights the need for careful monitoring and management in these patients.

Identification of glutathione conjugates and mercapturic acids of 1,2-dibromopropane in female BALB/c mice by liquid chromatography-electrospray ionization tandem mass spectrometry

Based on recent results that 1,2-dibromopropane (1,2-DBP) causes hepatotoxicity and immunotoxicity in female BALB/c mice as well as a reduction of hepatic glutathione levels, the possible formation of glutathione conjugates and mercapturic acids of 1,2-DBP was investigated in vivo in the present studies. The following four metabolites were identified in the liver at 12 h after treatment with 1,2-DBP, by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS): M1, 2-hydroxypropylglutathione; M2, 2-oxopropylglutathione; M3, N-acetyl-S-(2-hydroxypropyl)-L-cysteine; and M4, N-acetyl-S-(2-oxopropyl)-L-cysteine. Ions of individual conjugates were observed at m/z 366, 364, 222 and 220, respectively. Characteristic product ions at m/z 237, 217, 204 and 202 for the identification of M1, M2, M3 and M4 were observed, respectively. In the sera isolated from the same animals, only mercapturic acids (M3 and M4) were observed by LC-ESI/MS. When female BALB/c mice were treated orally with 1,2-DBP at doses of 150, 300 and 600 mg kg(-1) once for 12 h, the production of glutathione conjugates and mercapturic acids in liver was apparently dose dependent, as were the concentrations of them in sera. When the production of metabolites from 1,2-DBP was investigated in liver following oral treatment with 600 mg kg(-1) 1,2-DBP for 6, 12, 24 and 48 h, metabolite concentrations were greatest at the first time point (6 h). The results explain the authors' previous studies that oral treatment with 1,2-DBP reduces the hepatic content of glutathione.

Resin bonding using an all-etch or self-etch adhesive to enamel after carbamide peroxide and/or CPP-ACP treatment

BACKGROUND

Limited evidence exists regarding the effect of carbamide peroxide and casein phosphopeptide amorphous calcium phosphate (CPP-ACP) on composite-enamel bonding. Microshear bond strengths, using either a total-etch or self-etching adhesive, to enamel treated with carbamide peroxide and/or CPP-ACP were investigated.

MATERIALS AND METHODS

Twenty-six extracted human third molars were sectioned into four parts, each being allocated into one of the four groups (n=26): bleach (Polanight, 16% carbamide peroxide), CPP-ACP (GC Tooth Mousse), bleach and then CPP-ACP, or untreated (control). The surfaces were bonded with a total-etch bonding system (Single Bond) or a self-etching primer system (Clearfil SE Bond) and tested using a microshear test.

RESULTS

A significant difference in bond strength was found between bonding systems. SE Bond showed the highest bond strength to untreated enamel (p < 0.05). The microshear bond strength of SE Bond decreased when the enamel was treated with carbamide peroxide, CPP-ACP or both (p < 0.05). Only combined use of carbamide peroxide and CPP-ACP significantly affected microshear bond strength with Single Bond.

CONCLUSION

These findings suggest the shear bond strength of resin to enamel using a self-etching priming adhesive may be affected if the enamel is treated with a bleaching agent or CPP-ACP.

Evaluation of the biliary tract: The value of performing magnetic resonance cholangiopancreatography in conjunction with a 3-D spoiled gradient-echo gadolinium enhanced dynamic sequence

The 3-D gradient-echo (GRE) sequence allows thinner sections and better resolution of biliary obstruction. When the presence of biliary obstruction is identified using magnetic resonance cholangiopancreatography, the addition of the 3-D GRE sequence may be helpful for diagnosing biliary obstruction. By showing the changes in the bile duct wall, within the duct lumen and around the bile duct, this technique can be helpful for distinguishing benign from malignant stricture as well as a stone from an enhancing intraluminal mass.

A mechanical spike accompanies the action potential in Mammalian nerve terminals

Large and rapid changes in light scattering accompany secretion from nerve terminals of the mammalian neurohypophysis (posterior pituitary). In the mouse, these intrinsic optical signals are intimately related to the arrival of the action potential E-wave and the release of arginine vasopressin and oxytocin (S-wave). Here we have used a high bandwidth atomic force microscope to demonstrate that these light-scattering signals are associated with changes in terminal volume that are detected as nanometer-scale movements of a cantilever positioned on top of the neurohypophysis. The most rapid mechanical response ("spike"), having a duration shorter than the action potential but comparable to that of the E-wave, represents a transient increase in terminal volume due to water movement associated with Na(+)-influx. The slower mechanical event ("dip"), on the other hand, depends upon Ca(2+)-entry as well as on intraterminal Ca(2+)-transients and, analogously to the S-wave, seems to monitor events associated with secretion.

Changes in FAD and NADH fluorescence in neurosecretory terminals are triggered by calcium entry and by ADP production

We measured changes in the intrinsic fluorescence (IF) of the neurosecretory terminals of the mouse neurohypophysis during brief (1-2 s) trains of stimuli. With fluorescence excitation at either 350 +/- 20 or 450 +/- 50 nm, and with emission measured, respectively, at 450 +/- 50 or > or = 520 nm, DeltaF/F(o) was approximately 5-8 % for a 2 s train of 30 action potentials. The IF changes lagged the onset of stimulation by approximately 100 ms and were eliminated by 1 microM tetrodotoxin (TTX). The signals were partially inhibited by 500 microM Cd(2+), by substitution of Mg(2+) for Ca(2+), by Ca(2+)-free Ringer's with 0.5 mM EGTA, and by 50 microM ouabain. The IF signals were also sensitive to the mitochondrial metabolic inhibitors CCCP (0.3 microM), FCCP (0.3 microM), and NaN(3) (0.3 mM), and their amplitude reflected the partial pressure of oxygen (pO(2)) in the bath. Resting fluorescence at both 350 nm and 450 nm exhibited significant bleaching. Flavin adenine dinucleotide (FAD) is fluorescent, while its reduced form FADH(2) is relatively non-fluorescent; conversely, NADH is fluorescent, while its oxidized form NAD is non-fluorescent. Thus, our experiments suggest that the stimulus-coupled rise in [Ca(2+)](i) triggers an increase in FAD and NAD as FADH(2) and NADH are oxidized, but that elevation of [Ca(2+)](i), alone cannot account for the totality of changes in intrinsic fluorescence.

Characterization of the Phase II metabolites of rutaecarpine in rat by liquid chromatography-electrospray ionization-tandem mass spectrometry

From the authors' previous studies on the Phase I metabolism of rutaecarpine, nine metabolites formed were identified as products of hydroxylation on the aromatic rings in rat liver microsomes. In order to determine the possible metabolic fate of rutaecarpine, the Phase II metabolites of rutaecarpine were characterized in the present study by using liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS). When male Sprague-Dawley rats were treated intravenously with 4 mg kg(-1) rutaecarpine, 16 different Phase I and II metabolites were identified in urine including four sulfate and four glucuronide conjugates. Phase I metabolites of rutaecarpine were identified as four mono-hydroxylated metabolites (M2-5) and four isobaric di-hydroxylated metabolites (M6-9). These metabolites were identical to the in vitro metabolites except one, which was hydroxylated in the aliphatic moiety. In addition, Phase II metabolites were identified as conjugated with sulfate (S1-4) and glucuronide (G1-4). In faeces, 11 different metabolites were identified. The metabolites M8 and glucuronide conjugated (G1-4) were not detected. Structures of all metabolites were confirmed with CID fragmentation spectra of MS(2), MS(3) and retention times by LC/ESI-MS.

Quasimonoenergetic electron beam generation by using a pinholelike collimator in a self-modulated laser wakefield acceleration

A relativistic electron bunch with a large charge (>2 nC) was produced from a self-modulated laser wakefield acceleration configuration. For this experiment, an intense laser beam with a peak power of 2 TW and a duration of 700 fs was focused in a supersonic He gas jet, and relativistic high-energy electrons were observed from the strong laser-plasma interaction. By passing the electron bunch through a small pinholelike collimator, we could generate a quasimonoenergetic high-energy electron beam, in which electrons within a cone angle of 0.25 mrad (f/70) were selected. The beam clearly showed a narrow-energy-spread behavior with a central energy of 4.3 MeV and a charge of 200 pC. The acceleration gradient was estimated to be about 30 GeV/m. Particle-in-cell simulations were performed for comparison study and the result shows that both the experimental and simulation results are in good agreement and the electron trapping is initiated by the slow beat wave of the Raman backward wave and the incident laser pulse.

Duration curve analysis for the assessment of pathogen loading from diffuse sources

Pathogen level of surface waters has received great attention for protecting public health. In this study, total coliform, fecal coliform and Escherichia coli concentrations were monitored as the pathogen indicator organisms at six monitoring stations in the Geum River, Korea. Rainfall runoff from two agricultural-forestry watersheds was analyzed for their microbial aspect as well. Total coliform concentration of the Geum River showed high correlation with the flow rate. To estimate total coliform loading on the Geum River in probability scale, the duration curve method was applied. In addition, a standard duration curve reflecting the water quality criteria was constructed to determine water quality compliance. Under the assumption of linearity between flow rate and total coliform concentration of the Geum River, total coliform duration curve revealed that total coliform concentrations exceed the desired criteria mainly due to pollutants from diffuse sources.

Smad4 expression in gastric adenoma and adenocarcinoma: frequent loss of expression in diffuse type of gastric adenocarcinoma

Smads are signal transducers for the members of the TGF-beta superfamily. Of these Smads, Smad4 is essential for TGF-beta signaling. The purpose of this study was to elucidate Smad4 expression and localization in 65 gastric adenomas, 49 intestinal-type and 39 diffuse type of gastric adenocarcinomas (including 12 cases of fresh frozen tissue) using Real-time RT-PCR and immunohistochemistry. Real-time RT-PCR showed that intestinal type gastric adenocarcinomas have higher Smad4 mRNA expression than diffuse type gastric adenocarcinomas. Immunohistochemical stain for Smad4 revealed that expression of Smad4 was significantly lower in diffuse-type gastric adenocarcinoma than intestinal-type gastric adenocarcinomas. Also, higher Smad4 protein expression in intestinal type gastric adenocarcinomas than overall gastric adenoma was noted. The rate of reduced Smad4 expression was higher in advanced gastric cancer than early gastric cancer. These results suggest that Smad4 might play different roles in human gastric carcinogenesis, especially between intestinal type and diffuse type of gastric adenocarcinoma.

Which types of stent, uncovered or covered, should be used in gastric outlet obstructions?

BACKGROUND

Self-expandable metallic stents (SEMS) have been widely used in inoperable malignant gastric outlet obstructions, but stent obstructions caused by tumor ingrowth and migration are a major problem of SEMS. The aims of this study were to assess the rate of stent restenosis, to identify lesion characteristics related to early restenosis by tumor ingrowth, and, in particular, to find suitable patient groups for uncovered or covered stents at first implantation.

METHODS

Forty-nine patients were reviewed: stomach cancer in 34 patients, primary duodenal cancer in 3 patients, pancreatic cancer in 5 patients, and common bile duct cancer in 7 patients. In principle, uncovered stents were initially placed at the time when obstruction symptoms occurred and the endoscope would not pass through. Stent obstruction due to tumor ingrowth within 4 weeks after the first stent implantation was regarded as early stent restenosis.

RESULTS

Technical success was seen in 49/49 patients (100%). Migration did not occur. Stent obstructions caused by tumor overgrowth were found in 2/49 patients (4.1%) after 1 month. Stent obstructions caused by tumor ingrowth occurred in 14/49 patients (28.5%), and 7 of them (14.3%) were found to have early restenosis. The only statistically significant factor for early restenosis was stenosis site, and early restenosis was more frequent in the postoperative anastomosis site in the current study; a) 2/18 antropyloric obstructions (11.1%), b) 1/15 pyloric and duodenal bulb obstructions (6.7%), c) 0/10 duodenal second portion obstructions (0%), and d) 4/6 postoperative anastomosis site obstructions (66.7) (P < 0.05, 95% CI 0.003-0.005).

CONCLUSIONS

Uncovered stents are technically feasible and effective for most malignant gastric outlet obstructions. However, because of frequent early restenosis among patients with postoperative anastomosis site obstructions, the placement of covered or simultaneous dual stents to prevent early restenosis should be considered when stenting postoperative anastomosis site obstructions.

Serum keratan sulphate as a cartilage metabolic marker in horses: the effect of exercise

Keratan sulphate (KS) concentration in sera from resting horses and horses training daily on a racetrack was measured by an inhibition enzyme-linked immunosorbent assay (ELISA) using anti-equine KS antibody 1/14/16H9. For the in-training horses, serum KS concentrations in 2-year-old-horses was significantly higher than 3- or 4-year-old-horses. A higher concentration of serum KS was found in the in-training group than in the long-term resting group in 2-year-old-horses. Serum KS concentration increased remarkably immediately after training in healthy horses, and at 1, 5, 9 and 24 h after training remained at similar levels to the pre-training concentration. The results suggest that serum KS concentration could represent the situation of joint loading, induced by daily racetrack training, affecting the metabolic activities in joint cartilage.

Development of an intelligent laboratory information system for community health promotion center

This study aimed to develop an Intelligent Laboratory Information System (ILIS) for the community health promotion center in Kwachun city to help process an increasing number of laboratory test data in an efficient manner, and to support the clinical decision-making of public health doctors. A sample of 170 cases was used for validation of the system. Overall, the system correctly predicted 92.5% of the cases. This paper also analyzed the economic feasibility of the ILIS based on the Information Economics approach. The results showed that the ILIS not only helps screen more people by increasing the capacity of a health promotion center, but also brings in more revenue to the center.

Regulation of the abundance of renal sodium transporters and channels by vasopressin

Vasopressin plays a role in both salt and water balance in the kidney. Classic studies, utilizing isolated perfused tubules, have revealed that vasopressin increases sodium reabsorption in the kidney thick ascending limb and the collecting duct. Furthermore, the activity of several sodium transport proteins expressed in these segments, such as the bumetanide-sensitive Na-K-2Cl cotransporter (NKCC2) and the epithelial sodium channel (ENaC), have been shown to be directly increased by vasopressin. Increased protein abundance might be one means through which sodium transporter and channel activity is enhanced. We have used immunoblotting and immunohistochemistry in order to investigate the regulation of abundance of the major sodium transporters and channels expressed along the renal tubule in response to vasopressin. Chronic (7-day) studies were performed in which vasopressin levels were elevated either endogenously by water restriction of Sprague-Dawley rats or exogenously through infusion of the vasopressin V2-receptor-selective agonist, dDAVP (1-deamino-8d-arginine-vasopressin), to Brattleboro rats. We found a significant increase in protein abundance for NKCC2 and the beta- and gamma-subunits of ENaC with either water restriction or dDAVP infusion. The alpha-subunit of Na-K-ATPase was increased by water restriction, but not by dDAVP infusion, and alpha-ENaC and the thiazide-sensitive cotransporter (NCC) were increased by dDAVP infusion but not by water restriction. Acute (60-min) in vivo exposure to dDAVP led to an increase in both beta- and gamma-ENaC abundance in kidney cortex homogenates, displaying the rapid nature of some of these changes. Overall these increases in sodium transporter and channel abundances likely contribute to both the antidiuretic and antinatriuretic actions of vasopressin.

Clinical significance of the fractional excretion of anions in metabolic acidosis

The fractional excretion of anions has been proposed as a new index for the differential diagnosis of metabolic acidosis, identifying the properties of the conjugate base by examining the renal handling of the anion. Here, we investigated clinical significance of the fractional excretion of anions in pathophysiologic diagnosis of metabolic acidosis by measuring urine ammonium (NH4+) excretion, the ratio of A plasma anion gap/delta plasma HCO3- concentration (deltaAG/deltaHCO3-), and fractional excretion of anions in three different groups of metabolic acidosis: acid overproduction (8 patients with lactic acidosis, 8 with diabetic ketoacidosis, 3 with hippuric acidosis following glue sniffing), acid underexcretion (10 patients with chronic renal failure) and normal controls (10 normal volunteers who underwent 3-day NH4Cl loading). As expected, urine NH4+ excretion was higher in overproduction acidosis than in acid-loaded normal controls (88.1 +/- 12.3 vs. 54.0 +/- 3.7 mmol/day, p < 0.05), and it was lower in chronic renal failure than in acid-loaded normal controls (12.8 +/- 1.7 vs. 54.0 +/- 3.7 mmol/day, p < 0.05). The fractional excretion of anions had no difference between overproduction acidosis and chronic renal failure (41.2 +/- 42.8% vs. 41.0 +/- 8.1%). However, the fractional excretion of anions showed significant differences between the subgroups in acid overproduction (lactic acidosis, 4.7 +/- 0.3%; diabetic ketoacidosis, 45.8 +/- 3.1%; hippuric acidosis, 126.0 +/- 14.4%; p < 0.05). The ratio of plasma deltaAG/deltaHCO3- also exhibited significant differences between the subgroups in acid overproduction (lactic acidosis, 1.5 +/- 0.1; diabetic ketoacidosis, 1.0 +/- 0.1; hippuric acidosis, 0.3 +/- 0.1; p < 0.05). There was an inverse linear correlation between the fractional excretion of anions and the ratio of plasma deltaAG/deltaHCO3- (r2 =-0.89, p < 0.05). In conclusion, determination of the fractional excretion of anions may provide a useful clue to the differential diagnosis of metabolic acidosis caused by acid overproduction.

Life without a cell membrane: regeneration of protoplasts from disintegrated cells of the marine green alga Bryopsis plumosa

When the multi-nucleate giant cells of the green alga Bryopsis plumosa (Huds.) Ag. are injured, the protoplasm is extruded from the cells and can generate spontaneously numerous new cells. The cell organelles aggregate rapidly in seawater and become covered with a gelatinous envelope within 15 minutes. A lipid cell membrane is formed inside the envelope within 9 to 12 hours and about 15% of the original cell membrane is recycled to make the membrane of new protoplasts. Cytochemical studies using Nile Red and various enzymes revealed that the primary envelope is initially composed of polysaccharides, and then transformed into a polysaccharide-lipid complex. Fluorescein diacetate staining showed that the primary envelope has some characteristics of a cell membrane including semi-permeability and selective transport of materials. The aggregation of cell organelles appears to be mediated by two kinds of materials, one present in vacuolar sap and the other on the surface of the cell organelles. About a thousand new cells were generated from a single disintegrated branch and 40% of them eventually developed into mature plants.