Hydrodynamics-based delivery of the viral interleukin-10 gene suppresses experimental crescentic glomerulonephritis in Wistar-Kyoto rats

Gene therapy is expected to revolutionize the treatment of kidney diseases. Viral interleukin (vIL)-10 has a variety of immunomodulatory properties. We examined the applicability of vIL-10 gene transfer to the treatment of rats with crescentic glomerulonephritis, a T helper 1 (Th 1) predominant disease. To produce the disease, Wistar-Kyoto rats were injected with a rabbit polyclonal anti-rat glomerular basement membrane antibody. After 3 h, a large volume of plasmid DNA expressing vIL-10 (pCAGGS-vIL-10) solution was rapidly injected into the tail vein. pCAGGS solution was similarly injected into control rats (pCAGGS rats). We confirmed the presence of vector-derived vIL-10 mainly in the liver and observed high serum vIL-10 levels in pCAGGS-vIL-10-injected rats. Compared with the pCAGGS rats, the pCAGGS-vIL-10 rats showed significant therapeutic effects: reduced frequency of crescent formation, decrease in the number of total cells, macrophages, and CD4+ T cells in the glomeruli, decrease in urine protein, and attenuation of kidney dysfunction. Using quantitative real-time polymerase chain reaction, we also observed that this model was Th1-predominant in the glomeruli and that the ratio of the transcripts of CD4, interferon-gamma, tumor necrosis factor-alpha, and monocyte chemotactic protein-1 to the transcripts of glucose-6-phosphate dehydrogenase in the glomeruli were all significantly lower in the pCAGGS-vIL-10 rats than in the pCAGGS rats. These results demonstrate that pCAGGS-vIL-10 gene transfer by hydrodynamics-based transfection suppresses crescentic glomerulonephritis.

High-level expression of naked DNA delivered to rat liver via tail vein injection

BACKGROUND

High levels of foreign gene expression in mouse hepatocytes can be achieved by rapid tail vein injection of a large volume of a naked DNA solution, the 'hydrodynamics-based procedure'. Rats are more tolerant of the frequent phlebotomies required for monitoring blood parameters than mice, and thus are better for some biomedical research.

METHODS

We tested this technique for the delivery of a therapeutic protein in normal rats, using a rat erythropoietin (Epo) expression plasmid vector, pCAGGS-Epo.

RESULTS

We obtained maximal Epo expression when the DNA solution was injected in a volume of 25 ml (approximately 100 ml/kg body weight) within 15 s. We observed a dose-response relationship between serum Epo levels and the amount of injected DNA up to 800 microg. Using quantitative real-time PCR, the vector-derived Epo mRNA expression was mainly detected in the liver. When a lacZ expression plasmid was injected similarly, beta-galactosidase was exclusively detected in the liver, mainly in hepatocytes. Toxicity attributable to the technique was mild and transient, as assessed by histochemical analysis. Epo gene expression and erythropoiesis occurred with Epo gene transfer in a dose-dependent manner, and persisted for at least 12 weeks, the last time point examined. Repeated administration of the plasmid DNA also effectively led to erythropoiesis.

CONCLUSIONS

These results demonstrate that gene transfer into the liver via rapid tail vein injection can easily be achieved in the rat, which is more than 10 times larger than the mouse, and has significant value for gene function analysis in rats.

Bacteroides forsythus hemagglutinin is inhibited by N-acetylneuraminyllactose

Bacteroides forsythus, which has been recognized as a pathogen associated with periodontitis, produces a hemagglutinin. The hemagglutinin was localized in the envelope of B. forsythus. The hemagglutinating activity was inhibited by lactose at concentrations as low as 1 mM, and by L-arginine and L-lysine at concentrations of 100 mM. N-Acetylneuraminyllactose (NeuAc-lactose) was at least 100 times more potent an inhibitor than lactose, as it completely inhibited the hemagglutination at concentrations below 10 microM. This is similar to the Helicobacter pylori hemagglutinin. The hemagglutinin was heat-labile, and resistant to treatment with proteases such as trypsin. A specific antibody raised against one of the S-layer proteins that are major species-specific proteins had no inhibitory effect on the hemmaglutination. These results suggest that the NeuAc-lactose-sensitive adhesin of B. forsythus may play an important role in colonization in the oral cavity.

Skin-targeted gene transfer using in vivo electroporation

The skin is an important target for gene transfer because of its easy accessibility. Using plasmid DNA expressing rat erythropoietin (pCAGGS-Epo) as the vector, we previously demonstrated long-term Epo delivery in rats by muscle-targeted gene transfer using in vivo electroporation. Here we examined whether this electroporation approach could be applied to gene delivery in rat skin. To optimize gene transfer, we tested the efficiency of skin-targeted Epo gene transfer with three types of electrodes at three different electrode voltages. Each rat was injected intradermally with a total of 800 microg of pCAGGS-Epo, in the abdominal area. Plate-and-fork-type electrodes were effective for Epo delivery by skin-targeted gene transfer at low voltages (12 approximately 24 V). The vector-derived Epo mRNA was expressed only at the DNA injection site. The Epo gene was expressed in a dose-dependent manner, the expression persisted for 7 weeks, and hematocrit levels were increased for 11 weeks. Skin injection with pCAGGS-lacZ showed lacZ gene expression in the epidermis on day 1 after injection and in the subcutaneous muscle layer on day 7. Slight skin damage due to the gene transfer procedure was evident on day 1, but absent by day 7. These results demonstrate that skin-targeted pCAGGS-Epo transfer by in vivo electroporation at low voltage is a useful procedure for the short-term delivery of Epo.

[Swallowing rehabilitation in two elderly patients with cerebral infarction]

We report two cases of cerebral infarction in which swallowing function improved following swallowing rehabilitation. Patient 1 was an 82-year-old man, who was admitted due to rheumatoid arthritis and multiple cerebral infarction, suffering from aspiration pneumonia. The abnormality of swallowing was assessed by the water swallowing test and videofluorography. It has been reported that videofluorography is useful in the diagnosis of aspiration. Three weeks after the start of swallowing rehabilitation, the serum level of inflammatory markers and the chest X-ray had returned to normal. His score on the water swallowing test had improved. Patient 2 was a 68-year-old [correction of 62] man, who was admitted with severe hemiplegia, dysphagia and dysarthria. One month after the swallowing rehabilitation, videofluorography showed that the magnitude of aspiration into the trachea had decreased and the pooling of barium in the piriform sinus had disappeared. The patient could begin taking a little food by mouth. These results suggest that swallowing rehabilitation will be affect the clinical improvement of swallowing function and help preventing aspiration pneumonia in our hospital.

Localization of major, high molecular weight proteins in Bacteroides forsythus

Bacteroides forsythus produces species-specific major proteins with high molecular weights of 270 and 230-kDa (270K and 230K). A specific antibody raised against 270K was used for Western blot analysis and immunoelectron microscopy. Western blot analysis showed that the 270K and 230K proteins were immunologically similar. Immunogold labeling of ultrathin-sectioned bacterial cells and biochemical fractionation revealed that these proteins were localized at the outermost cell surface, not in the cytoplasm. These results suggest that major proteins ubiquitous to this species may form the S-layer.

Long-term production of erythropoietin after electroporation-mediated transfer of plasmid DNA into the muscles of normal and uremic rats

The anemia associated with chronic renal failure is one of the best target diseases for erythropoietin (Epo) gene transfer. We previously reported a short-term (1 month) study of continuous rat Epo delivery by muscle-targeted gene transfer of plasmid DNA expressing rat Epo (pCAGGS-Epo) using in vivo electroporation in normal rats. Here, we performed a long-term pharmacokinetic study of continuous Epo delivery by this method in normal rats and uremic five-sixths nephrectomized rats. In normal rats, Epo gene expression and sufficient erythropoiesis occurred with Epo gene transfer in a dose-dependent manner, and persisted for at least 11 weeks. Repeated administration of the plasmid DNA effectively produced erythropoiesis. Similar erythropoiesis was observed in the uremic rats, and persisted for more than 15 weeks. Both normal and uremic rats showed a significant decrease in platelet count. Moreover, the uremic rats showed Epo-induced hypertension, which is the major side-effect of recombinant human Epo. These results demonstrate that muscle-targeted pCAGGS-Epo transfer by in vivo electroporation is a useful procedure for the long-term continuous delivery of Epo in both normal and uremic rats.

Decomposition and carbon cycling of dead trees in tropical forests of the central Amazon

Decomposition rate constants were measured for boles of 155 large dead trees (>10 cm diameter) in central Amazon forests. Mortality data from 21 ha of permanent inventory plots, monitored for 10-15 years, were used to select dead trees for sampling. Measured rate constants varied by over 1.5 orders of magnitude (0.015-0.67 year^-1), averaging 0.19 year^-1 with predicted error of 0.026 year. Wood density and bole diameter were significantly and inversely correlated with rate constants. A tree of average biomass was predicted to decompose at 0.17 year^-1. Based on mortality data, an average of 7.0 trees ha^-1 year^-1 died producing 3.6 Mg ha^-1 year^-1 of coarse litter (>10 cm diameter). Mean coarse litter standing-stocks were predicted to be 21 Mg ha^-1, with a mean residence time of 5.9 years, and a maximum mean carbon flux to the atmosphere of 1.8 Mg C ha^-1 year^-1. Total litter is estimated to be partitioned into 16% fine wood, 30% coarse wood, and 54% non-woody litter (e.g., leaves, fruits, flowers). Decomposition rate constants for coarse litter were compiled from 20 globally distributed studies. Rates were highly correlated with mean annual temperature, giving a respiration quotient (Q ₁₀) of 2.4 (10°C^-1).

Continuous erythropoietin delivery by muscle-targeted gene transfer using in vivo electroporation

It has been demonstrated that gene transfer by in vivo electroporation of mouse muscle increases the level of gene expression by more than 100-fold over simple plasmid DNA injection. We tested continuous rat erythropoietin (Epo) delivery by this method in normal rats, using plasmid DNA expressing rat Epo (pCAGGS-Epo) as the vector. A pair of electrodes was inserted into the thigh muscles of rat hind limbs and 100 microg of pCAGGS-Epo was injected between the electrodes. Eight 100-V, 50-msec electric pulses were delivered through the electrodes. Each rat was injected with a total of 400 microg of pCAGGS-Epo, which was delivered to the medial and lateral sides of each thigh. The presence of vector-derived Epo mRNA at the DNA injection site was confirmed by RT-PCR. The serum Epo levels peaked at 122.2 +/- 33.0 mU/ml on day 7 and gradually decreased to 35.9 +/- 18.2 mU/ml on day 32. The hematocrit levels increased continuously, from the preinjection level of 49.5 +/- 1.1 to 67.8 +/- 2.2% on day 32 (p < 0.001). In pCAGGS-Epo treated rats, endogenous Epo secretion was downregulated on day 32. In a control experiment, intramuscular injection of pCAGGS-Epo without subsequent electroporation did not significantly enhance the serum Epo levels. These results demonstrate that muscle-targeted pCAGGS-Epo transfer by in vivo electroporation is a useful procedure for the continuous delivery of Epo.

A survey of filling methods, intracanal medications, and instrument breakage

The present survey was conducted to obtain answers to some basic questions regarding the use of intracanal medications, root canal filling methods, and the intracanal breakage of instruments. A letter was sent to 300 endodontists listed in the 1995-1996 membership roster of the American Association of Endodontists. Eighty-five replies were received. Calcium hydroxide as an intracanal medication was used by 91.7% of the responding endodontists. With regard to the root canal filling technique, 52.9% used the lateral condensation method. When intracanal breakage occurred, 95.3% of the respondents informed the patient. The results of this survey provide useful information for the education of undergraduate dental students.

Changes in the carbon balance of tropical forests: evidence from long-term plots

The role of the world's forests as a "sink" for atmospheric carbon dioxide is the subject of active debate. Long-term monitoring of plots in mature humid tropical forests concentrated in South America revealed that biomass gain by tree growth exceeded losses from tree death in 38 of 50 Neotropical sites. These forest plots have accumulated 0.71 ton, plus or minus 0.34 ton, of carbon per hectare per year in recent decades. The data suggest that Neotropical forests may be a significant carbon sink, reducing the rate of increase in atmospheric carbon dioxide.

Thoracoscopic en bloc total esophagectomy with radical mediastinal lymphadenectomy

OBJECTIVE

Total esophagectomy with en bloc mediastinal lymphadenectomy for cancer carries a substantial morbidity and mortality rate. To investigate the feasibility of thoracoscopic technique, we carried out an extensive laboratory study. Encouraged by our excellent results, we conducted a clinical trial.

METHODS

From September 1994 to September 1995, 39 patients thoracic esophageal cancer lesions not invading surrounding organs underwent total esophagectomy with mediastinal lymphadenectomy by means of thoracoscopy. Ages ranged from 47 to 86 years. The procedures were conventional except for the thoracic portion, which was performed as a thoracoscopic procedure with six trocar holes instead of thoracotomy. All harvested lymph nodes were counted for each station. Spirometric data and plethysmographically determined vital capacity were measured before and after operation for all patients.

RESULTS

All procedures were accomplished as scheduled, and none was converted to open thoracotomy. The operating time was 200 +/- 41 minutes (mean +/- standard deviation). Estimated blood loss was 270 +/- 157 ml. The harvested lymph nodes numbered 19.7 +/- 11.1 per patient. Seventeen patients (45%) had positive lymph nodes. There were no in-hospital deaths within 30 days. Twenty-two patients did not require postoperative ventilatory support. Vital capacity decreased to 85% +/- 11% of the preoperative values, and forced expiratory volume in 1 second decreased to 82% +/- 16%.

CONCLUSIONS

Thoracoscopic mediastinal lymphadenectomy is technically feasible, and its completeness is comparable to that of the open technique. The decline in pulmonary function is significantly less than that seen in our previous experience with the open technique.

[Home care that meets the wishes of patients with terminal stage cancer and their families]

As our ward is a general surgical ward, we formerly had difficulties providing appropriate care for patients with terminal cancer. To solve the problem, we have formed a nursing study group in order to provide home care that would meet the wishes of such patients and their families. Our specific approach was as follows: 1) preparation of a form on which patient information is collected; 2) a support system for home care (such as pain control and home parenteral nutrition; and 3) a solid collaboration system between ward nurses and visiting nurses. Such a program enables us to understand the wishes of patients and families and to provide various support where needed. The project helps to lessen the anxiety and the burden that patients and families feel in home care, and improve the quality of life (QOL).

[CT anatomy of the caudate lobe of the liver]

The anatomy of the portal vein branches in the caudate lobe of the liver was studied in 20 patients by double-phase CT arterial portography (DP-CTAP). DP-CTAP provided excellent images of the portal venous system in the first phase and the perfusion defects of intrahepatic tumors in the second phase. From DP-CTAP images of the first phase, a sufficient number of interpolated images were created for a smooth paging display. The ramifying structures of the portal system were traced on the monitor using the tracking ball. This method was found to be very effective and reliable for the anatomical assessment of the caudate lobe. The number and origins of the caudal portal branches were investigated in each case, and the caudate lobe of the liver could be divided into right and left segments.

[Fast spin echo MRI techniques. Contrast characteristics and clinical potentials]

Based on partial RF echo planar principles, Fast Spin Echo techniques (FSE) were implemented on high field systems. These methods produce image quality and contrast which resemble to conventional spin echo (SE) techniques. By reducing acquisition times by factors between 1.4 and 16 over SE methods, FSE allows for several imaging options usually prohibitive with conventional spin echo (SE) sequences. These include fast scans (especially breath-hold acquisitions); improved T2 contrast with longer TR intervals; increased spatial resolution with the use of larger image matrices and/or smaller fields of view; and 3D volume imaging with a 3D multislab FSE technique. Contrast features of FSE techniques are directly comparable to those of multiple echo SE sequences using the same echo spacing than FSE methods. However, essential contrast differences existing between the FSE sequences and their routine asymmetric dual SE counterpart can be identified. Decreased magnetic susceptibility effects and increased fat signal present within T2 weighted images compared to conventional dual SE images are due to the use of shorter echo spacings employed in FSE sequences. Off-resonance irradiation inherent to the use of a large number of radio frequency pulses in shown to results in dramatic magnetization contrast transfer effects in FSE images acquired in a multislice mode.

[CT angiography of the liver]

The diagnostic efficacy of CT arterial portography (CTAP) for the hepatic tumors has been established. We developed the double-phase incremental CTAP (DP-CTAP) using a fast CT scanner, by which the double-phase scanning of the whole liver was made during a single contrast administration. The DP-CTAP was performed in 9 cases of hepatic diseases, and was useful for the lesion detection and improvement of the visualization of the liver vasculatures. The maximum density projection angiogram of the portal and hepatic veins was easily made by DP-CTAP images, and useful for three dimensional understanding of the liver vasculatures and the detection of the vascular abnormalities.

Magnetic resonance imaging of the acute effects of interstitial neodymium:YAG laser irradiation on tissues

RATIONALE AND OBJECTIVES

Laser irradiation therapy in deep tissues requires a monitoring method other than visual guidance. Magnetic resonance imaging (MRI) can be used for this purpose because it visualizes soft tissue structures and heat distribution.

METHODS

The authors performed interstitial laser irradiations in rat livers with various laser outputs and measured the sizes of laser-induced lesions. MRI of these lesions was done ex vivo and compared with the histologic findings. Laser-induced lesions also were studied in rabbit brain, liver, and skeletal muscle to show the influences of tissue optical and thermal properties. Imaging of interstitial laser irradiation also was performed in vivo in rabbit brains.

RESULTS

MRI depicted the laser-induced lesions produced with different laser outputs and tissue types. MRIs of rabbit brain in vivo effectively demonstrated the signal decrease during heating and acute tissue changes.

CONCLUSION

MRI has potential for monitoring interstitial laser surgery or hyperthermia.

A novel method for fat suppression in RARE sequences

Rapid acquisition relaxation-enhanced (RARE) sequences (Hennig et al., Magn. Reson. Med. 3, 823 (1986)) utilize one or several Carr-Purcell-Meiboom-Gill (CPMG) echo trains to sample a number of k-space lines each repetition time TR. The technique can rapidly generate multislice T2-weighted images which, as a rule, are strikingly similar in contrast to conventional T2-weighted spin-echo (SE) images. An exception to this rule is the appearance of very bright signal from fat in T2-weighted RARE images as compared to conventional T2-weighted SE images. To reduce this fat signal, we introduce a time delay, tau c, between the 90 degrees x and first 180 degrees y pulse of each echo train such that a phase angle of pi/2 develops between fat and the reference (water) line at echo maxima. The technique leads to single-acquisition fat suppression without the use of frequency-selective saturation pulses and concomitant loss of slices per TR. A Bloch equation analysis is used to identify two major mechanisms contributing to suppression of off-resonance spins such that w tau c = pi/2. Namely, the CPMG sequence becomes a CP sequence with no self-correction properties for imperfect 180 degrees pulses leading to enhanced signal decay, and the raw k-space data matrix become segmented into blocks alternately multiplied by +/- i, leading to signal dispersion following Fourier transformation.

Rapid MR imaging of the pediatric brain using the fast spin-echo technique

PURPOSE

To evaluate diagnostic reliability and to establish optimal scanning techniques of a recently developed Fast Spin-echo MR pulse sequence that allows rapid proton density-weighted and T2-weighted imaging.

METHODS

We compared lesion conspicuity and signal intensity measurements on Fast Spin-echo and conventional spin-echo sequences in 81 patients ranging from 1 week to 25 years in age on a 1.5-T MR unit. A total of 28 Fast Spin-echo dual-echo images (14 slice locations) were obtained in 2:08 minutes with a 256 x 128 matrix or in 3:12 minutes with a 256 x 192 matrix at a TR of 2000 msec and two excitations.

RESULTS

Lesion conspicuity and characterization on Fast Spin-echo images compared favorably with conventional spin-echo images in our series when pseudo-TEs of 15 and 90 msec were employed for proton density-weighted and T2-weighted images, respectively. Fast Spin-echo images yielded diagnostic information in four nonsedated patients whose conventional spin-echo images were either degraded by motion or unobtainable. Fat signal remained bright on T2-weighted Fast Spin-echo images. Magnetic-susceptibility effects were slightly reduced with Fast Spin-echo but did not pose any diagnostic problem in our series.

CONCLUSION

Diagnostically reliable rapid dual-echo brain images can be obtained with Fast Spin-echo sequences.

Real-time magnetic resonance imaging of laser heat deposition in tissue

We applied diffusion-sensitive echo planar (Instascan) imaging to study thermal changes caused by a Nd:YAG laser. Images of phantom materials and normal rabbit brain tissue in vivo, acquired in 150 ms, every 2s, clearly showed the dynamics of temperature-related signal intensity changes in the regions irradiated by the laser.

Phase-encode order and its effect on contrast and artifact in single-shot RARE sequences

Substantial manipulation of tissue contrast can be achieved by varying the order in which phase-encode values are applied to individual echoes within a 128-echo single-shot rapid acquisition relaxation enhanced (RARE) sequence. Appropriate ordering can then permit imaging of short T2 species like muscle and white matter with single-shot RARE. For sequential phase encoding with an arbitrary initial phase-encode value, the timing of the zero phase (ZP) encoded echo is found to be analogous to the echo time (TE) of standard spin-echo sequences. This is demonstrated qualitatively with human brain images and is verified quantitatively with NiCl2 phantoms by correlating the time constant for signal decay with ZP echo time, with transverse relaxation times T2, as obtained with a 128-echo Carr-Purcell-Meiboom-Gill (CPMG) imaging sequence. Banding artifacts accompanying the discontinuous traverse through K space are experimentally demonstrated in a rectangular phantom and expressions are developed for determining the dependence of this artifact on the phase-encode gradient increments and durations, the ZP echo number, echo spacing, and T2. Simulations based on the expressions are shown to be useful for characterizing the observed "banding" artifacts perpendicular to the phase-encode direction and for predicting the extent of tissue-tissue overlap to be expected with the use of this ultrafast rf echo planar imaging method.