Simulation of ultrashort electron pulse generation from optical injection into wake-field plasma waves

A laser-plasma-based source of relativistic electrons is described in detail, and analyzed in two dimensions using theoretical and numeric techniques. Two laser beams are focused in a plasma, one exciting a wake-field electron plasma wave while another locally alters some electron trajectories in such a way that they can be trapped and accelerated by the wave. Previous analyses dealt only with one-dimensional models. In this paper two-dimensional particle-in-cell simulations and analysis of single particle trajectories show that the radial wake field plays an important role. The simulation results are interpreted to evaluate the accelerated electron beam's properties and compared with existing devices.

Hemodynamic changes in limb shaking TIA associated with anterior cerebral artery stenosis

Limb shaking TIA is a rare but well-known feature of severe carotid artery stenosis. The authors report a patient who developed recurrent shaking movements of a leg. An angiogram showed the focal stenosis of the anterior cerebral artery. Ictal and postacetazolamide SPECT scans suggested a local hyperfunction of cortical neurons and an impaired hemodynamic reserve in the vicinity of the ischemic area.

Elective stenting for symptomatic middle cerebral artery stenosis presenting as transient ischaemic deficits or stroke attacks: short term arteriographical and clinical outcome

BACKGROUND

Although stent assisted angioplasty is an effective treatment for coronary and peripheral arterial disease, its efficacy in intracranial arteriosclerotic disease has not been verified.

OBJECTIVES

To assess the radiographic and clinical outcome of stent assisted angioplasty for symptomatic middle cerebral artery (MCA) stenosis.

METHODS

We attempted stent assisted angioplasty in 14 patients with symptomatic high grade stenosis (>60%) on the proximal portion of the MCA, who had experienced either recurrent transient ischaemic attacks (TIAs) resistant to medical therapy or one or more stroke attacks. Patient records were analysed for angiographic characteristics, degree of stenosis, pre-procedural regimen of anti-platelet and/or anti-coagulation agents, use of devices, procedure related complications, pre-operative and post-operative single photon emission computed tomography (SPECT) findings, and clinical and radiographic outcomes.

RESULTS

Stent assisted angioplasty was successfully performed in 8 of 14 patients without any serious complications and unsuccessful in 2 of 14 patients due to the tortuous curve of the internal carotid artery siphon. Four patients had complications. Two patients had an arterial rupture; one patient was rescued by an additional stent and balloon tamponade, the other patient died. Complications in the other two patients included thrombotic occlusion and distal thrombosis. Residual stenosis was less than 50% in diameter in all the patients. All eight patients who underwent follow up cerebral angiography had no restenosis. Follow up SPECT showed improved perfusion in the affected MCA territory in all the tested patients with TIA and in one of three stroke patients. Using the modified Rankin Scale at follow up, four of five TIA patients and five of six stroke patients were assessed as functionally improved or having a stable clinical status.

CONCLUSION

Although the re-stenosis rate in stent assisted angioplasty seems to be better than in primary balloon angioplasty as reported previously, the complication rate is still high. Elective stenting is an alternative therapeutic method for the prevention of secondary ischaemic stroke in stroke patients with MCA stenosis, and seems to be a potentially effective but also hazardous therapeutic technique in patients with recurrent TIAs. This study indicates the need for randomised control trial data of this intervention. Additionally, long term follow up data and additional clinical experience are required to assess the durability of this procedure.

Usefulness of reversed display of soft-copy abdominal radiographs for urinary calculi detection

PURPOSE

To determine the usefulness of reversed display of soft-copy abdominal radiographs for urinary calculi detection.

MATERIAL AND METHODS

Sixty radiographs with a single urinary calculus less than 5 mm in the long diameter (15 in the kidney; 15 in the proximal ureter; 15 in the mid-ureter, 15 in the distal ureter) and 15 radiographs without calculi were evaluated. Four readers blinded to the presence or absence of urinary calculi on each radiograph reviewed the radiographs in the conventional display, reversed display, and combination of conventional and reversed displays at 1-week intervals. All images were evaluated in random order and the presence or absence of urinary calculi was interpreted using the confidence score from 1 to 5.

RESULTS

Multireader analysis for calculi in all locations showed a greater area under the receiver operating curve for combination of the two displays (0.764) than for the conventional display alone (0.655) (P=0.031). In the single-reader analysis for calculi in all locations, the third reader showed a greater area under the receiver operating curve for the reversed display (0.784) than for the conventional display (0.622) (P=0.027). Multireader analysis of the calculi in the kidney showed a greater area under the receiver operating curve for combination of the two displays (0.824) than for the conventional display alone (0.703) (P=0.043).

CONCLUSION

The reversed display of soft-copy abdominal radiographs may be useful for urinary calculi detection.

GDC Embolization of Intracranial Aneurysms with SAH and Mass Effect by Subdural Haematoma. A Case Report and Review

SUMMARY

A 43-year-old woman was brought to the emergency room due to the sudden onset of severe headache and stuporous consciousness. She had no history of head injury. Computerized tomography scan revealed subarachnoid haemorrhage and left SDH with midline shift of about 10 mm. Cerebral angiography demonstrated anterior communicating artery and right middle cerebral artery bifurcation aneurysms. Her family refused operation due to her religion never to permit blood transfusion. So just aneurysm coiling and medical ICP control was planned. Guglielmi detachable coil (GDCs) embolization of the two aneurysms was successfully performed. She made a neurological recovery after embolization without evacuation of the SDH. She was discharged from hospital with no neurological deficit on day 21. We report our experience of successful GDC embolization on multiple aneurysms without craniotomy even in the selected case of mass effect.

Performance evaluation of leachate treatment system using innovative sulfur circulation method

A pilot-scale experimental study was carried out to evaluate the performance of an innovative method for early stabilization of landfill. This method employs sequential processes of: leachate collection; nitrification through aeration; sulfate addition in effluent tank; and leachate injection back to the landfill. This study focused on: 1) decomposition of recalcitrant organic matters, 2) the characteristics of denitrification, 3) sulfide oxidation for sulfate recovery, and 4) nitrification by aerating discharged leachate. It was found that, when sulfate (SO4(2-)) added leachate was introduced inside the landfill, sulfate-reducing bacteria decomposed recalcitrant organic matters like lignocellulose by using SO4(2-) as an electron acceptor and simultaneously sulfur-oxidizing bacteria denitrified the leachate using sulfides (H2S, HS-, S2-) as electron donors. These two types of bacteria existed not competitively but symbiotically on substrate utilization. Sulfate-reducing bacteria produced S2- while sulfur-oxidizing bacteria oxidized S2- to SO4(2-). During aeration, the concentration of NO3(-)-N increased from near zero up to 925 mg l(-1). Eventual denitrification efficiency in the simulated waste landfill was observed to be approximately 92.3%. Also, S2- present in the discharged leachate was converted to SO4(2-) again in the aeration process. Sulfate needed in this process could be recirculated. Therefore, the amount of sulfate required in the operation of this method could be maintained marginal after the initial addition of sulfate in the effluent tank. Decomposition of recalcitrant organic matters and denitrification hastened the stabilization of landfill. The results of this study indicated that this innovative method was effective and economic.

Endoscopic hemoclipping using a transparent cap in technically difficult cases

BACKGROUND AND STUDY AIMS

Technical difficulties have been experienced in endoscopic hemoclipping on the posterior wall of the body of the stomach because the angle of approach is tangential. It has been suggested that the use of a transparent cap on the tip of the endoscope could help to solve this problem. The purpose of this study was to examine the efficacy of endoscopic hemoclipping using a transparent cap over the tip of the endoscope.

PATIENTS AND METHODS

A total of 74 patients with a bleeding peptic ulcer or stigmata of recent hemorrhage underwent endoscopic hemoclipping. Technical difficulty in hemoclipping was experienced in 18 patients and the transparent cap was used in these cases. We therefore conducted a nonrandomized prospective study to compare bleeding control with the hemoclip with and without the aid of a transparent cap.

RESULTS

There were no statistically significant differences between the patients treated with the cap and those treated without the cap with regard to the initial hemostasis rate (94.4 % vs. 91.1 %), the rebleeding rate (11.7 % vs. 11.8 %), or the permanent hemostasis rate (94.4 % vs. 96.4 %).

CONCLUSIONS

Although there was no statistically significant difference between patients treated with or without a transparent cap, hemoclipping with the aid of the cap made it possible to clip a lesion too tangential to be clipped without it. However, this study did not compare conventional hemoclipping with hemoclipping using a cap because the cap was only used in cases in which conventional clipping had failed.

Multiple sclerosis: an important role for post-translational modifications of myelin basic protein in pathogenesis

Myelin basic protein (MBP) represents a candidate autoantigen in multiple sclerosis (MS). We isolated MBP from normal and MS human white matter and purified six components (charge isomers) to compare the post-translational modifications on each. The sites and extent of methylation, deimination, and phosphorylation were documented for all tryptic peptides by mass spectrometry. We found that mono and dimethylated arginine 107 was increased in MS samples; deimination of arginine occurred at a number of sites and was elevated in MS; phosphorylation was observed in 10 peptides in normal samples but was greatly reduced or absent in most peptides from MS samples. Data obtained with MBP isolated from fresh brain obtained from a spontaneously demyelinating mouse model supported the view that the changes observed in human brain were probably related to pathogenesis of demyelination, i.e. we found decreased phosphorylation and decreased amounts of glycogen synthesis kinase in brain homogenates using specific antibodies. This study represents the first to define post-translational modifications in demyelinating disease and suggest an important role in pathogenesis.

Spine needle biopsy simulator using visual and force feedback

OBJECTIVE

Biopsy with an inserted needle is an important procedure for lesion detection in the spine, but is difficult to perform due to the presence of many critical organs near the spine. This article presents a spine needle biopsy simulator, based on visual and force feedback, which can be used to plan the optimal path of a needle and to practice the procedure without risk.

MATERIALS AND METHODS

The simulator is composed of a 3D human model, a visual-feedback component, a force-feedback component, and an evaluation module. The human model is based on 3D CT data. The visual-feedback component provides an oblique section, multiplanar reformatting images, and a volume-rendered image. Of these, the oblique section display is very useful for planning a 3D path for the needle. During simulation, the force-feedback component generates and provides realistic forces acting on the biopsy needle in real time by synchronizing them to visual feedback. After each simulation, the evaluation module provides a performance analysis for the trainee.

RESULTS

For an XCT abdomen volume data set of 256 x 256 x 256, the update rate of image rendering due to needle movement is over 25 Hz, with a force-feedback rate of 1 kHz. This performance proved to be good enough for the trainee to learn the relationship between visual and force feedback.

CONCLUSIONS

The simulator is useful for the planning of and training in complicated 3D spine needle biopsy procedures. It may be used as an educational tool for beginners, a practice tool to increase expertise, or a test bed for new procedures.

CT analysis of postoperative tumor recurrence patterns in periampullary cancer

BACKGROUND

We analyzed postoperative tumor recurrence in periampullary cancer on computed tomography (CT).

METHODS

Forty-six patients with tumor recurrence (16 pancreas head cancers, 19 distal common bile duct cancers, and 11 ampulla of Vater cancers) of 125 patients who underwent surgery for periampullary cancer were enrolled. Recurrence was diagnosed by CT findings plus elevated CA 19-9 (n = 28) or biopsy (n = 18). Two radiologists retrospectively reviewed 156 contrast-enhanced CT scans, with 7-mm slice thickness, obtained in our institution until the initial diagnosis of tumor recurrence. The modes of recurrence were classified as local recurrence, hepatic metastasis, lymph node metastasis, peritoneal carcinomatosis, or extraabdominal metastasis. We evaluated the time of recurrence, the frequency of each mode of recurrence, and the earliest mode of recurrence. The differences in tumor recurrence for the three types of periampullary cancer were evaluated.

RESULTS

Half of the recurrences occurred within 6 months after surgery and 87% occurred within 12 months after surgery. Local recurrences (67%), hepatic metastases (72%), and lymph node metastases (61%) were common modes of tumor recurrence. Pancreas head cancers recurred earlier than the other types of periampullary cancer (p < 0.05).

CONCLUSION

Periampullary cancer tends to recur early after surgery, usually as a local recurrence, hepatic metastasis, or lymph node metastasis.

Pictorial review: CT urography and virtual endoscopy: promising imaging modalities for urinary tract evaluation

CT urography and virtual endoscopy images are generated from dedicated multislice helical CT data sets and various three-dimensional reconstruction techniques. These imaging techniques can provide external and endoscopic images of the urinary tract and also provide high spatial resolution images helping overcome some of the limitations of intravenous urography and ultrasound. This pictorial review presents clinical applications of CT urography and virtual endoscopy in various urinary tract abnormalities.

Distribution of nociceptin-like immunoreactivity in the central nervous system of the Mongolian gerbil: an immunohistochemical study

This study is designed to demonstrate the distribution of nociceptin, endogenous ORL1 receptor ligand, in the central nervous system of the Mongolian gerbil. To intensify the nociceptin-like immunoreactivity (NOC-LI), colchicine was administered into the lateral ventricle, at 48 h prior to the transcardiac perfusion. In the group without colchicine treatment, NOC-LI was observed in the fibres of the spinal dorsal horn, specifically in the superficial layers. However, the NOC-LI in the superficial layers disappeared after the administration of colchicine. In the brain, NOC-LI was prominent in the hypothalamus, hippocampus, cerebral peduncle, substantia nigra, dorsal raphe, periaqueductal grey, locus coeruleus and trapezoid nucleus. Colchicine treatment markedly intensified the NOC-LI in the somata of the central nervous system, whereas the untreated sections were too weak to observe and analyse. The distribution of NOC-LI provides informative data for studies of the neuronal circuit that nociceptin may be involved in.

Digital envelope detector for blood pressure measurement using an oscillometric method

Blood pressure measurement in the finger artery offers some advantages compared with that in the brachial artery. However, volume oscillometric signals obtained from finger artery measurement are often influenced by motion artefact due to respiration, speaking, involuntary or voluntary movement, etc. In this paper, we developed a digital envelope detector to detect the maximum oscillation criterion in blood pressure measurement for the first time. The digital envelope detector is robust to noise signals generated by motion artefact and filters out the carrier frequency efficiently. To verify the feasibility of our method, we measured blood pressure for eight subjects using our developed system. The results were compared with the auscultation method. In the case of using a digital envelope detector, we could reduce the mean difference error and standard deviation by 30-40%. Our proposed digital envelope detector is a useful tool to improve the accuracy of blood pressure measurement in finger artery.

The role of KCNQ1/KCNE1 K(+) channels in intestine and pancreas: lessons from the KCNE1 knockout mouse

KCNE1 (IsK, minK) co-assembles with KCNQ1 (KvLQT1) to form voltage-dependent K(+) channels. Both KCNQ1 and KCNE1 are expressed in epithelial cells of gut and exocrine pancreas. We examined the role of KCNQ1/KCNE1 in Cl(-) secretion in small and large intestine and exocrine pancreas using the KCNE1 knockout mouse. Immunofluorescence revealed a similar basolateral localization of KCNQ1 in jejunum and colon of KCNE1 wild-type and knockout mice. Electrogenic Cl(-) secretion in the colon was not affected by gene disruption of KCNE1; in jejunum forskolin-induced short-circuit current was some 40% smaller but without being significantly different. Inhibition of KCNQ1 channels by 293B (IC(50) 1 micromol l(-1)) and by IKS224 (IC(50) 14 nmol l(-1)) strongly diminished intestinal Cl(-) secretion. In exocrine pancreas of wild-type mice, KCNQ1 was predominantly located at the basolateral membrane. In KCNE1 knockout mice, however, the basolateral staining was less pronounced and the distribution of secretory granules was irregular. A slowly activating and 293B-sensitive K(+) current was activated via cholinergic stimulation in pancreatic acinar cells of wild-type mice. In KCNE1 knockout mice this K(+) current was strongly reduced. In conclusion intestinal Cl(-) secretion is independent from KCNE1 but requires KCNQ1. In mouse pancreatic acini KCNQ1 probably co-assembled with KCNE1 leads to a voltage-dependent K(+) current that might be of importance for electrolyte and enzyme secretion.

Prenatal detection of mesoblastic nephroma by sonography and magnetic resonance imaging

Congenital mesoblastic nephroma is the most common neonatal kidney tumor and surgical excision is almost always curative. We report the prenatal detection of congenital mesoblastic nephroma by sonography and magnetic resonance imaging. After birth, a right nephrectomy was performed and the baby recovered well.

Expression of brain-derived neurotrophic factor in rat dorsal root ganglia, spinal cord and gracile nuclei in experimental models of neuropathic pain

Chronic constriction injury of the sciatic nerve and lumbar L5 and L6 spinal nerve ligation provide animal models for pain syndromes accompanying peripheral nerve injury and disease. In the present study, we evaluated changes in brain-derived neurotrophic factor (BDNF) immunoreactivity in the rat L4 and L5 dorsal root ganglia (DRG) and areas where afferents from the DRG terminates (the L4/5 spinal cord and gracile nuclei) in these experimental models of neuropathic pain. Chronic constriction injury induced significant increase in the percentage of small, medium and large BDNF-immunoreactive neurons in the ipsilateral L4 and L5 DRG. Following spinal nerve ligation, the percentage of large BDNF-immunoreactive neurons increased significantly, and that of small BDNF-immunoreactive neurons decreased markedly in the ipsilateral L5 DRG, while that of BDNF-immunoreactive L4 DRG neurons of all sizes showed marked increase. Both chronic constriction injury and spinal nerve ligation induced significant increase in the number of BDNF-immunoreactive axonal fibers in the superficial and deeper laminae of the L4/5 dorsal horn and the gracile nuclei on the ipsilateral side. Considering that BDNF may modulate nociceptive sensory inputs and that injection of antiserum to BDNF significantly reduces the sympathetic sprouting in the DRG and allodynic response following sciatic nerve injury, our results also may suggest that endogenous BDNF plays an important role in the induction of neuropathic pain after chronic constriction injury and spinal nerve ligation. In addition, the increase of BDNF in L4 DRG may contribute to evoked pain which is known to be mediated by input from intact afferent from L4 DRG following L5 and L6 spinal nerve ligation.

Some general regularities of synergistic interaction of hyperthermia with various physical and chemical inactivating agents

Various cellular systems have been analysed for synergistic interactions of the simultaneous action of hyperthermia with physical agents including ionizing radiation, ultraviolet light, and ultrasound, and with chemical agents including thio-TEPA and cis-DDP. Some general rules of synergistic interaction were revealed. First, for every constant rate or intensity of exposure to physical factors or concentration of chemical agents, synergy can be observed only within a certain temperature range that is different for various cellular systems. Secondly, within this range, there is a specific temperature that maximizes the synergistic effect. Any deviation of temperature from the optimal one results in a reduction in synergy. Thirdly, the rate of exposure to physical agents or the concentration of chemical agents strongly influences the synergy; i.e. as the dose rate or concentration is reduced, the temperature for maximum synergism decreases. Possible interpretations of the mechanisms responsible for these relationships of synergy are discussed.

Molecular cloning and characterization of Mycobacterium bovis BCG pcp gene encoding pyrrolidone carboxyl peptidase

The Mycobacterium bovis bacilli Calmette-Guerin (BCG) pcp gene that encodes the pyrrolidone carboxyl peptidase (Pcp) was cloned from a lambdagtll genomic library and sequenced. The nucleotide sequence contains a 669 bp open reading frame coding for a protein of 222 amino acid residues with a calculated molecular mass of 23,209 Da. The deduced amino acid sequence is highly homologous to the Pcps from Bacillus amyloliquefaciens, Pseudomonas fluorescens, Bacillus subtilis, Streptococcus pyogenes, and Staphylococcus aureus. A multiple sequence alignment revealed highly conserved domains. The BCG pcp gene was overexpressed in Escherichia coli. The Pcp was purified to homogeneity. The recombinant protein was further confirmed by an enzymatic assay.

Role of glucocorticoid hormones in arginine vasopressin gene regulation

The mechanism underlying increased AVP synthesis and release in glucocorticoid deficiency is not known. Therefore, the present study was undertaken to investigate whether the mechanism was at the level of AVP gene transcription. The AVP gene promoter contains a consensus GRE, a CRE, and four AP2 sites. To assess the functional importance of these sites, 5' deletions of the AVP promoter were created and transient transfections were performed. Promoter activity in hypothalamic cells transfected with deletions lacking the GRE or both the GRE and CRE exhibited higher activity when compared to longer constructs containing both sites. In neuroblastoma cells, only the deletion lacking the GRE exhibited increased AVP promoter activity over the longer construct. These results are consistent with the idea that glucocorticoids suppress AVP gene expression by acting on a GRE in the AVP promoter region. Further, dexamethasone inhibited AVP promoter activity by >50% in hypothalamic cells transfected with the GRE-containing construct. In conclusion, the data presented here support a central mechanism to explain, at least in part, the nonosmotic increase in AVP with glucocorticoid deficiency.

Exposure rate as a determinant of the synergistic interaction of heat combined with ionizing or ultraviolet radiation in cell killing

A synergistic interaction of hyperthermia with ionizing or UV light (254 nm) radiation was analyzed in experiments with yeast cells. For a fixed dose rate of radiation, the synergism was shown to be observed only within a definite temperature range (40-45 degrees C), inside of which there was an optimal temperature to achieve the highest synergism. The effectiveness of the synergistic interaction was smaller for haploid cells than for diploid cells. Experimental data from diploid yeast cells evidenced the significance of the exposure rate in the synergistic interaction of heat combined with ionizing or ultraviolet radiation. The data show that the less is the intensity of radiation, the lower is the temperature that should be used to provide some definite, or highest, synergistic interaction with the radiation. To demonstrate the significance of this rule for other cellular systems, the results of other authors published for bacterial spores and mammalian cells are discussed. Calculations from these results have confirmed the revealed relationship between the dose rate and the exposure temperature. On this basis, it is inferred that synergism may take place at small intensities of harmful environmental factors existing in the biosphere. Hence, any assessment of the health or environmental risks should take into account synergistic interactions between harmful agents.

Retinal vein occlusion in two patients with primary antiphospholipid syndrome

Primary antiphospholipid syndrome (APS) is a disease producing vascular thrombus with antiphospholipid antibody without association with autoimmune diseases as systemic lupus erythematosus. Retinal vein occlusion is a rare vascular manifestation in primary APS. We describe 2 cases of primary APS presenting with developing blurred vision. Each had central retinal vein occlusion and high titer of IgG anticardiolipin antibody.

The covalent structure of the small subunit from Pseudomonas putida amine dehydrogenase reveals the presence of three novel types of internal cross-linkages, all involving cysteine in a thioether bond

Pseudomonas putida contains an amine dehydrogenase that is called a quinohemoprotein as it contains a quinone and two hemes c as redox active groups. Amino acid sequence analysis of the smallest (8.5 kDa), quinone-cofactor-bearing subunit of this heterotrimeric enzyme encountered difficulties in the interpretation of the results at several sites of the polypeptide chain. As this suggested posttranslational modifications of the subunit, the structural genes for this enzyme were determined and mass spectrometric de novo sequencing was applied to several peptides obtained by chemical or enzymatic cleavage. In agreement with the interpretation of the X-ray electronic densities in the diffraction data for the holoenzyme, our results show that the polypeptide of the small subunit contains four intrachain cross-linkages in which the sulfur atom of a cysteine residue is involved. Two of these cross-linkages occur with the beta-carbon atom of an aspartic acid, one with the gamma-carbon atom of a glutamic acid and the fourth with a tryptophanquinone residue, this adduct constituting the enzyme's quinone cofactor, CTQ. The thioether type bond in all four of these adducts has never been found in other proteins. CTQ is a novel cofactor in the series of the recently discovered quinone cofactors.

Extrahepatic portal vein tear with intraperitoneal hemorrhage during TIPS

Temporary occlusion with an angioplasty balloon can stop intraperitoneal bleeding.

Sino-aortic denervation alters the hemodynamic response to exercise in hypertensive rats

The effect of sino-aortic denervation (SAD) on the heart rate (HR), arterial pressure (AP) and regional blood flow responses during dynamic exercise was examined in spontaneously hypertensive rats (SHR). Intact (n= 14) and SAD (n= 17) rats were instrumented with arterial catheters and mesenteric and iliac Doppler ultrasonic flow probes. After recovery, all rats underwent a graded exercise test. Heart rate increased significantly during exercise in intact and SAD rats. There was no significant difference in the steady state heart rate response to exercise in the intact and SAD rats. Arterial pressure increased during exercise in the intact rats. In sharp contrast, arterial pressure decreased during exercise in the SAD rats. Iliac vascular conductance increased during exercise in the intact and SAD rats. The increase in iliac vascular conductance during exercise was significantly greater in the SAD rats. Mesenteric vascular conductance decreased during exercise in the intact and SAD rats. The decrease in mesenteric vascular conductance during exercise was significantly attenuated in the SAD rats. Results suggest that functioning arterial baroreceptors are required for the typical hemodynamic responses during dynamic treadmill running in hypertensive rats.

Srg3, a mouse homolog of yeast SWI3, is essential for early embryogenesis and involved in brain development

Srg3 (SWI3-related gene product) is a mouse homolog of yeast SWI3, Drosophila melanogaster MOIRA (also named MOR/BAP155), and human BAF155 and is known as a core subunit of SWI/SNF complex. This complex is involved in the chromatin remodeling required for the regulation of transcriptional processes associated with development, cellular differentiation, and proliferation. We generated mice with a null mutation in the Srg3 locus to examine its function in vivo. Homozygous mutants develop in the early implantation stage but undergo rapid degeneration thereafter. An in vitro outgrowth study revealed that mutant blastocysts hatch, adhere, and form a layer of trophoblast giant cells, but the inner cell mass degenerates after prolonged culture. Interestingly, about 20% of heterozygous mutant embryos display defects in brain development with abnormal organization of the brain, a condition known as exencephaly. Histological examination suggests that exencephaly is caused by the failure in neural fold elevation, resulting in severe brain malformation. Our findings demonstrate that Srg3 is essential for early embryogenesis and plays an important role in the brain development of mice.

Selection of a potential probiotic Lactobacillus strain and subsequent in vivo studies

The probiotic potential of a Lactobacillus strain, isolated from pig faeces, was assessed as a probiotic in piglets. The strain was examined for resistance to pH 2.0, 0.5% oxgall and antibiotics, and antimicrobial activities against enteric pathogenic bacteria. The probiotic strain, L. reuteri BSA131, was administered through the feed to 25 1-month-old Landrace piglets. The piglets were divided into five groups of five piglets each and fed with different diets for 28 days. The daily consumption of L. reuteri BSA131 was assigned into two groups by the concentration of 10(6) or 10(8) freeze-dried bacteria. Fecal samples were collected before, during, and after consumption. Lactobacilli and enterobacteria cell counts were determined in the fecal samples. The liveweight gains and feed consumption of the piglets were recorded daily. This study showed that strain BSA131 enhanced liveweight gains and feed conversion rates in piglets. It also showed a significant increase in lactobacilli cell counts and decreases in enterobacterial numbers in the fecal samples. Strain BSA131 was considered to be a potential probiotic for piglets, especially after weaning.

Influence of enterotoxin on mucosal intranet: selective inhibition of extrathymic T cell development in intestinal intraepithelial lymphocytes by oral exposure to heat-labile toxin

We tested the possibility that heat-labile enterotoxin of Escherichia coli (LT) affects the development of extrathymic T cells in the intraepithelial lymphocyte (IEL) compartment. After oral administration of LT, the number of extrathymic CD8alphaalpha+ IEL was selectively and significantly diminished when compared with the corresponding cells in phosphate-buffered saline-fed control mice. To clarify the mechanism behind this selective reduction of CD8alphaalpha+ IEL, we analyzed the expression of essential cytokines and their corresponding receptors for the mucosal intranet formed by intestinal epithelial cells (IEC) and IEL. The expression levels of stem cell factor, interleukin (IL)-7, and IL-15 in IEC, and their corresponding receptors, i. e. c-kit, IL-7 receptor, and IL-15 receptor, in CD8alphaalpha+ IEL were reduced following oral feeding with LT. These findings suggest that LT negatively regulates development of CD8alphaalpha+ IEL via the disruption of mucosal intranet-associated cytokine and cytokine receptors, which are required for the development and/or expansion of extrathymically developed T cells. Further, LT-induced destruction of the mucosal intranet resulted in the impairment of IEC generation via an increase of apoptosis.

Peritoneal dialysis in diabetic patients

Diabetic nephropathy is the leading cause of end-stage renal disease worldwide. Although death rates of diabetic patients on hemodialysis and peritoneal dialysis (PD) have decreased substantially, they remain higher than rates in nondiabetics on both modalities. PD offers equal or better survival than hemodialysis for younger diabetic patients during early years of dialysis. PD technique survival does not appear different between diabetic and nondiabetic patients but is inferior to hemodialysis technique survival. PD may accelerate changes in peritoneal membrane structure and function in diabetics. Peritonitis and conventional PD solutions containing high glucose and glucose degradation products are implicated in PD technique failure. Increased peritoneal expression of vascular endothelial growth factor and transforming growth factor-beta1 and excessive accumulation of advanced glycosylation end products may be involved in the progressive increase in membrane permeability, loss of ultrafiltration, and peritoneal fibrosis. Nonglucose PD solutions or solutions containing low glucose degradation products may prevent or delay alterations in peritoneal membrane structure and function in diabetic as well as nondiabetic patients during long-term PD.

Regulation of slowly activating potassium current (I(Ks)) by secretin in rat pancreatic acinar cells

1. The secretagogue-activated K(+) conductance is indispensable for the electrogenic Cl(-) secretion in exocrine tissue. In this study, we investigated the effect of secretin and other cAMP-mediated secretagogues on the slowly activating voltage-dependent K(+) current (I(Ks)) of rat pancreatic acinar cells (RPAs) with the whole-cell patch clamp technique. 2. Upon depolarization, RPAs showed I(Ks) superimposed upon the instantaneous background outward current. Secretin (5 nM), vasoactive intestinal peptide (5 nM), forskolin (5 microM), isoprenaline (10 microM) or 3-isobutyl-1-methylxanthine (IBMX, 0.1 mM) increased the amplitude of I(Ks) two- to fourfold. 3. The physiological concentration of secretin (50 pM) had a relatively weak effect on I(Ks) (160 % increase), which was significantly enhanced by transient co-stimulation with carbachol (CCh) (10 microM). However, the secretin-induced production of cAMP, which was measured by enzyme-linked immunosorbent assay, was not augmented by co-stimulation with CCh. 4. This study is the first to demonstrate the regulation of K(+) channels in RPAs by cAMP-mediated agonists. The I(Ks) channel is a common target for both Ca(2+) and cAMP agonists. The vagal stimulation under the physiological concentration of secretin facilitates I(Ks), which provides an additional driving force for Cl(-) secretion.

Notch1 confers a resistance to glucocorticoid-induced apoptosis on developing thymocytes by down-regulating SRG3 expression

We previously have reported that SRG3 is required for glucocorticoid (GC)-induced apoptosis in the S49.1 thymoma cell line. Activation of Notch1 was shown to induce GC resistance in thymocytes. However, the specific downstream target of Notch1 that confers GC resistance on thymocytes is currently unknown. We found that the expression level of SRG3 was critical in determining GC sensitivity in developing thymocytes. The expression of SRG3 also was down-regulated by the activated form of Notch1 (NotchIC). The promoter activity of the SRG3 gene also was down-regulated by NotchIC. Expression of transgenic SRG3 resulted in the restoration of GC sensitivity in thymocytes expressing transgenic Notch1. These results suggest that SRG3 is the downstream target of Notch1 in regulating GC sensitivity of thymocytes.

Dissolution of poorly crystalline apatite crystals by osteoclasts determined on artificial thin-film apatite

Poorly crystalline apatite (PCA) crystals introduced into bone tissue should be stable for a definite period before they are dissolved as a result of a host response. In this report, the dissolution of PCA crystals by the action of osteoclasts was studied on artificial thin films. These consisted of PCA crystals having similar crystallographic properties to bone crystals which were developed for assaying the osteoclast activity in vitro. The dissolution of minerals by osteoclasts decreased along with the decreased amount of labile phosphate and hydrogen phosphate domains of apatite crystals, which were caused by the crystal maturation temperature. A profound effect on mineral dissolution by pH in the culture medium was also shown. Low acidity considerably increased mineral dissolution, whereas a slight alkalinity totally blocked mineral dissolution. There was little difference in the mineral dissolution behavior of osteoclasts near the physiologic pH. In addition, it was determined whether mineral dissolution by osteoclasts was dependent on the destruction of the organic matrix. Nocodazole was introduced to inhibit the secretion of hydrolytic enzymes, and acetazolamide was added to inhibit acid production by the osteoclasts. There was no significant change as a result of nocodazole addition on mineral dissolution or by the addition of acetazolamide on degradation of collagen. These results indicate that small changes in the physicochemical properties of apatite crystals can decrease resorption by osteoclasts, which can be highly activated at low pH. These results also suggest that mineral dissolution and organic degradation by osteoclasts are self-regulating.

Prevention of fat-induced insulin resistance by salicylate

Insulin resistance is a major factor in the pathogenesis of type 2 diabetes and may involve fat-induced activation of a serine kinase cascade involving IKK-beta. To test this hypothesis, we first examined insulin action and signaling in awake rats during hyperinsulinemic-euglycemic clamps after a lipid infusion with or without pretreatment with salicylate, a known inhibitor of IKK-beta. Whole-body glucose uptake and metabolism were estimated using [3-(3)H]glucose infusion, and glucose uptake in individual tissues was estimated using [1-(14)C]2-deoxyglucose injection during the clamp. Here we show that lipid infusion decreased insulin-stimulated glucose uptake and activation of IRS-1-associated PI 3-kinase in skeletal muscle but that salicylate pretreatment prevented these lipid-induced effects. To examine the mechanism of salicylate action, we studied the effects of lipid infusion on insulin action and signaling during the clamp in awake mice lacking IKK-beta. Unlike the response in wild-type mice, IKK-beta knockout mice did not exhibit altered skeletal muscle insulin signaling and action following lipid infusion. In summary, high-dose salicylate and inactivation of IKK-beta prevent fat-induced insulin resistance in skeletal muscle by blocking fat-induced defects in insulin signaling and action and represent a potentially novel class of therapeutic agents for type 2 diabetes.

Functional inactivation of the IGF-I and insulin receptors in skeletal muscle causes type 2 diabetes

Peripheral insulin resistance and impaired insulin action are the primary characteristics of type 2 diabetes. The first observable defect in this major disorder occurs in muscle, where glucose disposal in response to insulin is impaired. We have developed a transgenic mouse with a dominant-negative insulin-like growth factor-I receptor (KR-IGF-IR) specifically targeted to the skeletal muscle. Expression of KR-IGF-IR resulted in the formation of hybrid receptors between the mutant and the endogenous IGF-I and insulin receptors, thereby abrogating the normal function of these receptors and leading to insulin resistance. Pancreatic beta-cell dysfunction developed at a relative early age, resulting in diabetes. These mice provide an excellent model to study the molecular mechanisms underlying the development of human type 2 diabetes.

Increased levels of circulating autoantibodies to cultured human bronchial epithelial cell in adult patients with nonatopic asthma

The pathogenetic mechanism of nonatopic asthma has not yet been defined. The idea of a possible involvement of autoimmunity in the pathogenesis of nonatopic asthma has been proposed by earlier studies. To evaluate the possible involvement of autoimmune response against bronchial epithelial cell in the pathogenesis of nonatopic asthma, we measured circulating autoantibodies to cultured human bronchial epithelial cell (BEAS-2B cell line) using enzyme-linked immunosorbent assay. We used stored serum samples form 38 age-matched healthy controls, 26 adult patients with atopic asthma, 16 adult patients with nonatopic asthma, and 12 adult patients with systemic lupus erythematosus. Levels of IgG autoantibodies to bronchial epithelial cell were significantly higher in patients with nonatopic asthma (mean+/-SD of absorbance values; 0.135+/-0.030) and systemic lupus erythematosus (0.293+/-0.181) than in healthy controls (0.112+/-0.016) and patients with atopic asthma (0.116+/-0.031) (p<0.05). This study showed that levels of circulating IgG autoantibodies to bronchial epithelial cell were increased in adult patients with nonatopic asthma. Further studies are needed to evaluate the possible involvement of autoimmune mechanism in the pathogenesis of nonatopic asthma.

Differential distribution of ganglioside GM3 in seminiferous tubule and epididymis of adult rats

Gangliosides are ubiquitous membrane components in mammalian cells and are suggested to play important roles in various functions such as cell-cell interaction, adhesion, cell differentiation, growth control and signaling. Among all ganglio-series gangliosides, GM3 has the simplest carbohydrate structure, and has been shown as a major ganglioside in male reproductive system. To study GM3 distribution in the seminiferous tubule and epididymis, frozen sections were stained with specific monoclonal antibody (MAb) against ganglioside GM3. In the seminiferous tubule of testis, pachytene spermatocytes and spermatids expressed ganglioside GM3, but not in spermatogonia and sertoli cells. Spermatogonia and sertoli cells near the basement membrane were negatively reacted to anti-GM3. In the epididymis, GM3 was expressed only in some interstitial cells. Taken together, these results suggest that the expression of ganglioside GM3 in rat seminiferous tubule and epididymis is spatio-temporally regulated during spermatogenesis.

Peripheral T cells become sensitive to glucocorticoid- and stress-induced apoptosis in transgenic mice overexpressing SRG3

Immature double-positive thymocytes are sensitive to glucocorticoid (GC)-induced apoptosis, whereas mature single-positive T cells are relatively resistant. Thymocytes seem to acquire resistance to GCs during differentiation into mature single-positive thymocytes. However, detailed knowledge concerning what determines the sensitivity of thymocytes to GCs and how GC sensitivity is regulated in thymocytes during development is lacking. We have previously reported that the murine SRG3 gene (for SWI3-related gene) is required for GC-induced apoptosis in a thymoma cell line. Herein, we provide results suggesting that the expression level of SRG3 protein determines the GC sensitivity of T cells in mice. SRG3 associates with the GC receptor in the thymus, but rarely in the periphery. Transgenic overexpression of the SRG3 protein in peripheral T cells induces the formation of the complex and renders the cells sensitive to GC-induced apoptosis. Our results also show that blocking the formation of the SRG3-GC receptor complex with a dominant negative mutant form of SRG3 decreases GC sensitivity in thymoma cells. In addition, mice overexpressing the SRG3 protein appear to be much more susceptible to stress-induced deletion of peripheral T cells than normal mice, which may result in an immunosuppressive state in an animal.

T cell receptor dynamism of mucosal and systemic CD4+ T cells in the course of an immune response to Escherichia coli heat-labile enterotoxin

The changes in T cell receptor (TCR) Vbeta expression, use, and clonality in mice orally challenged with Escherichia coli heat-labile enterotoxin (LT) were assessed. Use of the TCR Vbeta family and clonality were significantly changed at the single-cell level. In Peyer's patches of treated mice, use of TCR Vbeta6, Vbeta8, and Vbeta14 increased in CD4(+)CD44(+) T cells, compared with use in nontreated mice. On the other hand, use of TCR Vbeta1 and Vbeta8 was enhanced in splenic CD4(+)CD44(+) T cells. Intraepithelial lymphocytes isolated from LT-challenged mice showed expanded clonality (e.g., Vbeta1, Vbeta2, Vbeta9, and Vbeta18) and altered TCR Vbeta use (e.g., Vbeta15, Vbeta16, and Vbeta17). These findings reveal that oral administration of LT has distinct effects on mucosal versus systemic alphabeta T cells for induction of CD4(+) T cells with selected Vbeta use. This most likely reflects the function of LT as a mucosal modulator.

Glucose toxicity and the development of diabetes in mice with muscle-specific inactivation of GLUT4

Using cre/loxP gene targeting, transgenic mice with muscle-specific inactivation of the GLUT4 gene (muscle GLUT4 KO) were generated and shown to develop a diabetes phenotype. To determine the mechanism, we examined insulin-stimulated glucose uptake and metabolism during hyperinsulinemic-euglycemic clamp in control and muscle GLUT4 KO mice before and after development of diabetes. Insulin-stimulated whole body glucose uptake was decreased by 55% in muscle GLUT4 KO mice, an effect that could be attributed to a 92% decrease in insulin-stimulated muscle glucose uptake. Surprisingly, insulin's ability to stimulate adipose tissue glucose uptake and suppress hepatic glucose production was significantly impaired in muscle GLUT4 KO mice. To address whether these latter changes were caused by glucose toxicity, we treated muscle GLUT4 KO mice with phloridzin to prevent hyperglycemia and found that insulin-stimulated whole body and skeletal muscle glucose uptake were decreased substantially, whereas insulin-stimulated glucose uptake in adipose tissue and suppression of hepatic glucose production were normal after phloridzin treatment. In conclusion, these findings demonstrate that a primary defect in muscle glucose transport can lead to secondary defects in insulin action in adipose tissue and liver due to glucose toxicity. These secondary defects contribute to insulin resistance and to the development of diabetes.

CT differentiation of mesenteric ischemia due to vasculitis and thromboembolic disease

PURPOSE

The purpose of this work was to differentiate CT findings of acute mesenteric ischemia due to vasculitis (MV) or thromboembolism (MTE).

METHOD

CT scans of 69 patients with mesenteric ischemia caused by MV (n = 37) or MTE (n = 32) were analyzed. After dividing the patients into groups with and without MV, we compared them with regard to gastrointestinal tract involvement patterns, mesenteric changes, and presence or absence of vascular thrombosis, atherosclerosis, other organ changes, and ascites.

RESULTS

Duodenum was involved only in the MV group (30%). The MV group had preferential involvement of the small intestine (89%) to large intestine (51%), whereas the MTE group showed even distribution. Multisegmental bowel involvement was more common in the MV group (86%) than in the MTE group (44%), especially in both jejunum and ileum and both small and large intestine. The MV group showed prominent involvement of the superior mesenteric vessel territory, although the MTE group showed even distribution. Splenomegaly and hydronephrosis were more frequently seen in the MV group and vascular thrombosis and atherosclerosis in the MTE group.

CONCLUSION

Although considerable overlap was noted, CT is useful in differentiating MV from MTE.

Intracranial arteriovenous malformations: real-time auto-triggered elliptic centric-ordered 3D gadolinium-enhanced MR angiography--initial assessment

Auto-triggered elliptic centric-ordered three-dimensional (3D) gadolinium-enhanced magnetic resonance (MR) angiography was compared with 3D multiple overlapping thin-slab acquisition time-of-flight (TOF) MR angiography in the evaluation of intracranial arteriovenous malformations (AVMs) in 10 patients. Intraarterial digital subtraction angiography (DSA) was the reference standard. Gadolinium-enhanced MR angiograms were found to be equivalent to DSA images in AVM component depiction in 70%--90% of cases and were consistently superior to TOF MR angiograms.

Mitotic recombination and inactivation in Saccharomyces cerevisiae induced by UV-radiation (254 nm) and hyperthermia depend on UV fluence rate

In experiments with wild-type diploid yeast cells of Saccharomyces cerevisiae, the synergistic interaction of ultraviolet (UV) light (wavelength, 254 nm) and heat (45--60 degrees C) was studied both for mutagenic and inactivation effects. Simultaneous hyperthermia and UV light treatments increase the frequency of UV-induced mitotic intergenic recombination (crossing-over) and cell inactivation. The enhancing effect was a function of UV light fluence rate. It is concluded that the effect of hyperthermia on low fluence UV or high fluence UV irradiation results in comparable effects on survival and mitotic recombination suggesting similar modulation by hyperthermia of the effects induced by UV at different fluence rates. The interpretation of the data obtained was carried out within the widely accepted point of view considering the synergistic effects as a result of repair ability damage.

Abdominopelvic actinomycosis involving the gastrointestinal tract: CT features

PURPOSE

To assess the computed tomographic (CT) features of abdominopelvic actinomycosis involving the gastrointestinal tract.

MATERIALS AND METHODS

CT scans were analyzed in 18 patients with pathologically proved abdominopelvic actinomycosis involving the gastrointestinal tract. Eight patients had a history of using intrauterine contraceptive devices. Bowel site, wall thickness, length, bowel involvement patterns, inflammatory infiltration, and features of peritoneal or pelvic mass, if present, were evaluated at CT.

RESULTS

Of the gastrointestinal tract, the sigmoid colon was most commonly involved (50%). All patients showed concentric (n = 15) or eccentric (n = 3) bowel wall thickening, with a mean thickness of 1.2 cm and a mean length of 8.3 cm. The thickened bowel enhanced homogeneously in nine patients and heterogeneously in the other nine. Inflammatory infiltration was mostly diffuse and severe. In 17 patients, a peritoneal or pelvic mass (mean maximum diameter, 3.2 cm) was seen adjacent to the involved bowel and appeared to be heterogeneously enhanced in most cases; infiltration into the abdominal wall was seen in four patients.

CONCLUSION

Actinomycosis should be included in the differential diagnosis when CT scans show bowel wall thickening and regional pelvic or peritoneal mass with extensive infiltration, especially in patients with abdominal pain, fever, leukocytosis, or long-term use of intrauterine contraceptive devices.

Activation of mouse B lymphocyte by proteins containing hexahistidine

Many recombinant proteins are produced as a fusion protein tagging hexahistidine, which has been used for studying their biological function both in vitro and in vivo. Unexpectedly, we observed activation of BALB/c mouse splenocytes when treated with hexahistidine-tagged recombinant proteins. This activation was hexahistidine-specific since the anti-pentahistidine antibody completely neutralized the effect, and the bovine serum albumin conjugated with the hexahistidine peptides also showed a similar activation effect. The B cells seemed to be the activated splenocytes, since the cell population stained with the anti-immunoglobulin antibody and anti-CD80 antibody was increased after the treatment. However, the activation signal by hexahistidine was insufficient to fully differentiate the B lymphocytes. This result suggests that caution must be taken in the use of hexahistidine-tagged recombinant proteins, due to their nonspecific activation of B lymphocyte.

Syntaxin 4 heterozygous knockout mice develop muscle insulin resistance

To investigate the physiological function of syntaxin 4 in the regulation of GLUT4 vesicle trafficking, we used homologous recombination to generate syntaxin 4-knockout mice. Homozygotic disruption of the syntaxin 4 gene results in early embryonic lethality, whereas heterozygous knockout mice, Syn4(+/-), had normal viability with no significant impairment in growth, development, or reproduction. However, the Syn4(+/-) mice manifested impaired glucose tolerance with a 50% reduction in whole-body glucose uptake. This defect was attributed to a 50% reduction in skeletal muscle glucose transport determined by 2-deoxyglucose uptake during hyperinsulinemic-euglycemic clamp procedures. In parallel, insulin-stimulated GLUT4 translocation in skeletal muscle was also significantly reduced in these mice. In contrast, Syn4(+/-) mice displayed normal insulin-stimulated glucose uptake and metabolism in adipose tissue and liver. Together, these data demonstrate that syntaxin 4 plays a critical physiological role in insulin-stimulated glucose uptake in skeletal muscle. Furthermore, reduction in syntaxin 4 protein levels in this tissue can account for the impairment in whole-body insulin-stimulated glucose metabolism in this animal model.

Tissue-specific overexpression of lipoprotein lipase causes tissue-specific insulin resistance

Insulin resistance in skeletal muscle and liver may play a primary role in the development of type 2 diabetes mellitus, and the mechanism by which insulin resistance occurs may be related to alterations in fat metabolism. Transgenic mice with muscle- and liver-specific overexpression of lipoprotein lipase were studied during a 2-h hyperinsulinemic-euglycemic clamp to determine the effect of tissue-specific increase in fat on insulin action and signaling. Muscle-lipoprotein lipase mice had a 3-fold increase in muscle triglyceride content and were insulin resistant because of decreases in insulin-stimulated glucose uptake in skeletal muscle and insulin activation of insulin receptor substrate-1-associated phosphatidylinositol 3-kinase activity. In contrast, liver-lipoprotein lipase mice had a 2-fold increase in liver triglyceride content and were insulin resistant because of impaired ability of insulin to suppress endogenous glucose production associated with defects in insulin activation of insulin receptor substrate-2-associated phosphatidylinositol 3-kinase activity. These defects in insulin action and signaling were associated with increases in intracellular fatty acid-derived metabolites (i.e., diacylglycerol, fatty acyl CoA, ceramides). Our findings suggest a direct and causative relationship between the accumulation of intracellular fatty acid-derived metabolites and insulin resistance mediated via alterations in the insulin signaling pathway, independent of circulating adipocyte-derived hormones.

Effects of bicarbonate/lactate solution on peritoneal advanced glycosylation end-product accumulation

Advanced glycosylation end-products (AGEs) are associated with diabetic complications and peritoneal damage after long-term peritoneal dialysis (PD) with high glucose dialysis solutions. Glucose degradation products (GDPs) derived during heat sterilization of high glucose dialysis solutions are thought to accelerate AGE formation. A new technique of separating glucose from electrolytes has yielded markedly lower GDP levels and permitted the use of dialysis solutions containing the physiologic buffer bicarbonate. Formation of AGEs in vitro with this new solution is significantly lower compared with formation of AGEs with conventional solutions. The purpose of the present study was to investigate the effect of long-term intraperitoneal use of new, neutral dialysis solution (B/L) containing bicarbonate (25 mmol/L) and lactate (15 mmol/L) on peritoneal AGE accumulation and permeability. Normal male Sprague-Dawley rats were used. Twice daily for 12 weeks, 30 mL of new solution (B/L) or conventional solution [Lac (lactate 40 mmol/L)] was injected into the peritoneal cavity of the test rats. As a control, rats that were not injected were kept for 12 weeks in the same manner as the test rats. After 12 weeks, a 2-hour peritoneal equilibration test (PET) was performed in the test rats. After the PET, the parietal peritoneum and liver were obtained for evaluation of peritoneal morphology and for immunohistochemistry for AGE. Intensity of AGE staining was semi-quantitatively graded from 0 to 3. The omentum was also obtained and immediately frozen for analysis of pentosidine content by high-performance liquid chromatography. Compared with findings in the control group, hematoxylin and eosin staining of the parietal peritoneum and liver samples revealed partial denudation of mesothelial cells in the Lac group; denudation was not remarkable in the B/L group. The B/L solution showed significantly less AGE staining in the peritoneal cavity compared to conventional solution. However, B/L solution failed to lower pentosidine levels. Intraperitoneal volume and the ratio of dialysate glucose at 2 hours to dialysate glucose at instillation (D2/D0 glucose) were significantly lower and the ratio of dialysate urea to plasma urea at 2 hours (D2/P2 urea) was significantly higher in the Lac and B/L groups than in the control group. Intraperitoneal volume was significantly higher in the B/L group than in the Lac group; D2/D glucose and D2P2 urea did not differ between the two groups. In conclusion, peritoneal ultrafiltration decreased after long-term PD. The B/L solution showed a small but statistically significant protective effect against decreasing ultrafiltration as compared with Lac solution. The B/L solution attenuated peritoneal AGE accumulation compared with conventional solution, but did not affect peritoneal pentosidine levels. These findings indicate that biochemical kinetics of various AGE peptides are not unique, but multivalent.

Molecular screening for fragile X syndrome in mentally handicapped children in Korea

Fragile X syndrome is one of the most common forms of inherited mental retardation and is caused by the expansion of the CGG trinucleotide repeats in the FMR-1 gene. This study was aimed to facilitate the molecular screening of fragile X syndrome in Korean children with mental retardation of unknown etiology. The subjects were tested by Expand Long Template PCR system in the presence of 7-deaza-dGTP, and then by Southern blot analysis. The PCR method provided rapid and reliable results for the identification of fragile X negative and positive patients. One hundred one mentally retarded children (78 males and 23 females) were screened by PCR amplification, which detected only one abnormal sample. The PCR-positive case was confirmed by the CGG repeat expansion on Southern blot analysis with a positive cytogenetic result. In conclusion, Expand Long Template PCR may be used as the first screening test for detecting the fragile X syndrome.

The predictive parameters of erythropoietin hyporesponsiveness in patients on continuous ambulatory peritoneal dialysis

BACKGROUND

The present study was aimed at investigating the predictive parameters of erythropoietin (epoetin) hyporesponsiveness in patients on continuous ambulatory peritoneal dialysis (CAPD).

METHODS

We studied 40 patients with end-stage renal disease who had been receiving CAPD for at least 6 months and epoetin therapy for at least more than 2 months. Pearson's simple correlation and multiple stepwise linear regression analysis was used to discover what parameter can predict epoetin resistance. We expressed epoetin resistance index (ERI) as weekly epoetin dose/hematocrit/body weight'. The dose of epoetin is titrated by about 25% every 2 to 4 weeks to maintain a target hematocrit level between 33% and 36%.

RESULTS

We analyzed the relationship between ERI and other predictive parameters by Pearson's correlation. These results showed ERI has a statistically significant correlation with transferrin saturation (TS) (r = -0.327, p = 0.042), total weekly Kt/Vurea (r = -0.423, p = 0.018), serum albumin level (r = -0.458, p = 0.003), normalized protein catabolic rate (nPCR) (r = -0.479, p = 0.006), normalized protein equivalent of total nitrogen appearance (nPNA) (r = -0.488, p = 0.005) and serum C-reactive protein (CRP) (r = 0.332, p = 0.036). Regression analysis was performed using stepwise linear regression for multiple variables to discover the most independent variable which is correlated with ERI. ERI was entered as a dependent variable, whereas the other parameters (age, duration of peritoneal dialysis, serum albumin level, CRP, serum ferritin, total weekly Kt/Vurea, nPCR, nPNA, serum iPTH, serum aluminium, TS) were entered as independent variables. This analysis showed CRP is the most significant variable and, if CRP is excluded, nPNA is the significant variable. CRP has a statistically significant correlation with serum albumin level (r = -0.418, p = 0.007) and total weekly Kt/Vurea (r = -0.366, p = 0.043). High CRP group has more increased level of ERI (p < 0.05), age (p < 0.05) and serum creatinine level (p < 0.05) than normal control, but more decreased level of serum albumin (p < 0.01) and serum iron levels (p < 0.05).

CONCLUSION

These results indicate that CRP is the most important predictor of epoetin hyporesponsiveness.

Insulin resistance and a diabetes mellitus-like syndrome in mice lacking the protein kinase Akt2 (PKB beta)

Glucose homeostasis depends on insulin responsiveness in target tissues, most importantly, muscle and liver. The critical initial steps in insulin action include phosphorylation of scaffolding proteins and activation of phosphatidylinositol 3-kinase. These early events lead to activation of the serine-threonine protein kinase Akt, also known as protein kinase B. We show that mice deficient in Akt2 are impaired in the ability of insulin to lower blood glucose because of defects in the action of the hormone on liver and skeletal muscle. These data establish Akt2 as an essential gene in the maintenance of normal glucose homeostasis.