Refraction-enhanced tomography of mouse and rabbit lungs

In order to evaluate the effectiveness of edge enhancement by refraction in computed tomography, images of a cross section of a euthanized mouse thorax were recorded at low (20 keV) and high (72 keV) x-ray energies at a spatial resolution of about 40 microm. Compared with the images obtained with the detector at 30 cm from an object, when the object was located at 113 cm from the detector, the contrast between tissues and air was improved at both energies. The improvement was more pronounced at 72 keV where the absorption contrast was weaker. This effect was due to refraction at the surfaces of alveolar membranes and small airways which creates areas with apparently high and low linear attenuation coefficients within tissues. The edge enhancement by refraction was also effective in images of a euthanized rabbit thorax at x-ray energies of 40 and 70 keV at a spatial resolution of about 0.15 mm. These results raise the possibility that the refraction contrast may be utilized to obtain a high-resolution tomographic image of human lung and bone with low dose.

Phase contrast X-ray imaging of mice and rabbit lungs: a comparative study

The significant degree of X-ray phase contrast created by air-tissue interfaces, coupled with the poor radiographic contrast of conventional chest radiographs, makes the inflated lung an ideal candidate for investigating the potential diagnostic improvement afforded by phase contrast X-ray imaging. In small animals these methods highlight the lung airways and lobe boundaries and reveal the lung tissue as a speckled intensity pattern not seen in other soft tissues. We have compared analyser-based and propagation-based phase contrast imaging modalities, together with conventional radiographic imaging, to ascertain which technique shows the greatest image enhancement for various lung sizes. The conventional radiographic image of a mouse was obtained on a Siemens Nova 3000 mammography system, whilst phase contrast images of mice and rabbit chests were acquired at the medical imaging beamline (20B2) at the SPring-8 synchrotron radiation research facility in Japan. For mice aged 1 day, 1 week and 1 month old it was determined that analyser-based imaging showed the greatest overall image contrast, however, for an adult rabbit both techniques yielded excellent contrast. The success of these methods in creating high quality images for rabbit lungs raises the possibility of improving human lung imaging using phase contrast techniques.

Dynamic imaging of the lungs using x-ray phase contrast

High quality real-time imaging of lungs in vivo presents considerable challenges. We demonstrate here that phase contrast x-ray imaging is capable of dynamically imaging the lungs. It retains many of the advantages of simple x-ray imaging, whilst also being able to map weakly absorbing soft tissues based on refractive index differences. Preliminary results reported herein show that this novel imaging technique can identify and locate airway liquid and allows lung aeration in newborn rabbit pups to be dynamically visualized.

On the origin of speckle in x-ray phase contrast images of lung tissue

Phase contrast x-ray imaging of small animal lungs reveals a speckled intensity pattern not seen in other tissues, making the lungs highly visible in comparison to other organs. Although bearing a superficial resemblance to alveoli, the cause of this speckle has not been established. With a view to determining the mechanism for the formation of speckle, this paper details the results of propagation-based phase contrast experiments performed on mice lungs, together with packed glass microspheres used to emulate lung tissue. These experimental studies are compared to numerical simulations, based on wave propagation techniques. We find that speckle arises from focusing effects, with multiple alveoli acting as aberrated compound refractive lenses. Both experiments and modelling suggest that this speckle-formation phenomenon may lead to better screening methods for human lungs than conventional radiography.

Improved O3/H2O2 oxidation process for wastewater reclamation

A continuous two step O3/H2O2 oxidation system, in which the waste gas from the former reactor was reused in the latter step with an ejector, was established for the purpose of wastewater reclamation in electronics industries. ORP monitor was combined into the system to obtain the optimum ratio of H2O2 to O3 by automatically adjusting the dosage of H2O2, and ion exchange resin was used for removing organic acids formed during oxidation. The effectiveness of the O3/H2O2 oxidation system for TOC removal was investigated under various conditions by using IPA, DMSO, and NMP as model substances. The optimum H2O2/O3 for oxidizing IPA was in a range above 0.15, and it increased with the increase of O3 dose. A sudden drop of ORP from ca. 800 mV to a little more than 200 mV was observed when H2O2/O3 was approaching the optimum point from the lower end. An ORP between 250 mV and 300 mV or 800 mV and 900 mV was proper for H2O2/O3 control. The treatability of the model substances was in an order of IPA << DMSO < NMP, being consistent with the magnitude of the energy of the highest occupied molecular orbital (epsilon HOMO). The two step treatment system developed in this study was found to be more efficient than the conventional single step system. With the help of H2O2 dosing control and two step treatment using waste O3, the system could save about 40% O3 in comparison with the conventional O3/H2O2 oxidation process.

Malignant pheochromocytoma lacking clinical features of catecholamine excess until the late stage

A malignant pheochromocytoma is described in a 71-year-old man. Osseous metastases became manifest 12 years after successful removal of the primary tumor which originated in paraganglionic tissue near the right adrenal gland. Although the patient had no symptoms of catecholamine excess initially, hypertension, tachycardia and excessive sweating appeared several months before his death, concomitantly with a sharp increase in noradrenaline secretion due to an accelerated growth of metastatic tumors. Since there is no histologic criterion of malignancy in this neoplasm, it would be prudent to consider every case of pheochromocytoma as potentially malignant and to follow-up carefully for a long time after removal of the primary tumor.

Cinnabarinic acid was formed in damaged mitochondria and its effect on mitochondrial respiration

Tryptophan administration aggravates experimental mouse liver injury caused by carbon tetrachloride when 3-hydroxyanthranilic acid concentration elevates in serum. Tryptophan metabolism is changed by macrophages in injured liver. 3-Hydroxyanthranilic acid may be oxidized to cinnabarinic acid by injured mitochondria in the liver aggravating the state of injured liver. Mitochondria prepared from the liver 24 hr after CCl4 treatment have lost their ability of respiratory control. In consequence, 3-hydroxyanthranilic acid is oxidized to cinnabarinic acid by incubation with these mitochondria, whereas 3-hydroxykynurenine is not. Thus, formed cinnabarinic acid is able to inhibit completely the mitochondrial respiratory control at concentration of 10 microM.

Application of a floc-forming genetically engineered microorganism to a sequencing batch reactor for phenolic wastewater treatment

For enhancing the survival of genetically engineered microorganisms (GEMs) in activated sludge processes, the use of a floc-forming bacterium as the host for a recombinant plasmid was proposed. The floc-forming and phenol-degrading GEM Sphingomonas paucimobilis 551 (pS10-45) was cultured to demonstrate this proposal. Although the maximum growth rate of the host strain S. paucimobilis 551 was low and the recombinant plasmid pS10-45 was unstable in the host, the resultant GEM S. paucimobilis 551 (pS10-45) was difficult to wash out together with the effluent, and it maintained population 3-4 times higher than the non-floc-forming GEM Escherichia coli HB101 (pS10-45) in a model activated sludge process operated in a sequencing batch mode. In the long run, the GEM-inoculated activated sludge process showed better phenol removal ability by the recombinant plasmid and better sludge settlement by the host strain.

Oncogenic osteomalacia presenting as bilateral stress fractures of the tibia

We report on a patient with bilateral stress fractures of the tibia who subsequently showed classic biochemical features of oncogenic osteomalacia. Conventional radiographs were normal. MR imaging revealed symmetric, bilateral, band-like low-signal lesions perpendicular to the medial cortex of the tibiae and corresponding to the only lesions subsequently seen on the bone scan. A maxillary sinus lesion was subsequently detected and surgically removed resulting in prompt alleviation of symptoms and normalization of hypophosphatemia and low 1,25-(OH)2 vitamin D3. The lesion was pathologically diagnosed as a hemangiopericytoma-like tumor. Patients with oncogenic osteomalacia may present with stress fractures limited to the tibia, as seen in athletes. The clue to the real diagnosis lies in paying close attention to the serum phosphate levels, especially in patients suffering generalized symptoms of weakness and not given to unusual physical activity.

Decreased ureagenesis from alanine, but not from ammonia and glutamine, in the perfused rat liver after partial hepatectomy

Ureagenesis from ammonia, alanine, and glutamine in the liver after partial hepatectomy (PH) was determined by using the liver-perfusion system. The maximum rate of ureagenesis from ammonium chloride (10 mmol/L) in hepatectomized (HX) rats at 24 hours after surgery was obtained in the presence of ornithine, lactate, and pyruvate, and it was almost identical to that in sham-operated (SO) rats. The rate of urea production from glutamine (1 mmol/L or 10 mmol/L) in HX rats was significantly lower than that of SO rats with a concomitant decrease in hepatic glutaminase activities. However, the rate of urea synthesis from glutamine (1 mmol/L) in the presence of added ammonia (0.5 mmol/L) was accelerated approximately 10-fold, and the significant difference in the rate of urea formation between HX and SO rats was abolished. This result indicates that there is enough glutaminase to generate ammonia from glutamine in the liver of HX rats. The rate of urea production from alanine (1 mmol/L or 10 mmol/L) in HX rats was significantly decreased at 24 hours following surgery, while that of SO rats was increased. The decreased formation of urea from alanine was not seen at 72 and 120 hours after the operation. These results suggest that during the proliferation phase of liver regeneration, a reduction of ureagenesis from alanine facilitates the remnant liver to make nonessential amino acids such as aspartate. This metabolic alteration might be related to the proliferation of liver cells.

Redispersible dry emulsion system as novel oral dosage form of oily drugs: in vivo studies in beagle dogs

The absorption characteristics of vitamin E acetate (VEA) formulated into a dry emulsion system after its oral administration to beagle dogs were determined and compared to those of two different dosage forms (an oily mixture of the drug with cottonseed oil and an oil (drug)-in-water emulsion). The three dosage forms were administered in a crossover fashion to six nonfasting subjects, and the drug absorption was assessed from the plasma concentration of the major metabolite (free vitamin E). VEA formulated in the dry emulsion was rapidly absorbed, which suggested that a considerable amount was released as reformed emulsion droplets in the gastrointestinal tract as well as in water in vitro. Based on the analysis of variance, no significant differences in bioavailability parameters (AUC, Cmax or Tmax) were observed among the three dosage forms.

Tracheostomy--the horizontal tracheal incision

The complication rate after emergency tracheostomy is two to five times greater than after elective procedures. One of the main causes of the high risk of complications in emergency tracheostomy appears to be the amount of time required to open the trachea. Therefore, simple and fast procedures are mandatory. We have developed a new procedure as follows: A horizontal skin incision is performed. Strap muscles are dissected and retracted laterally. A transverse cut between tracheal rings below the thyroid isthmus is performed up to membranous portion of the trachea. The cut ends of the trachea remain open naturally because of the elasticity of the trachea. Skin and tracheal cut-ends are then joined by interrupted sutures. We have used this procedure during the past three years and have not experienced any major complications. This demonstrates the clear advantage and the more physiological nature of the procedure over various other incisions of the tracheal wall.

Effects of dose, pH, and osmolarity on nasal absorption of secretin in rats. II: Histological aspects of the nasal mucosa in relation to the absorption variation due to the effects of pH and osmolarity

Nasal absorption of secretin in rats was enhanced in an acid solution, and the maximum absorption was observed at a sodium chloride solution molarity of 0.462. In order to examine reasons for the variation of absorbability caused by the change of pH and osmolarity in secretin preparations, both a pretreatment study, in which the nasal mucosa was treated with placebo prior to the administration of a secretin preparation, and a histological study were conducted in rats. The nasal absorption of secretin was determined by measuring the increased secretin of pancreatic juice. Similar profiles of nasal absorption, both after intranasal administration of secretin preparations and as a result of pretreatment effects, were obtained in studies of the effects of pH and osmolarity. However, in the pH-effect study, the absorption with the use of active preparations was observed to be significantly larger than that with the pretreatment effect below a pH of 4.79, and significantly smaller than that with the pretreatment effect at a pH of 7 to 8. The results of histological studies revealed structural changes of the epithelial cells of the nasal mucosa at pH 2.94, and shrinkage of epithelial cells was observed at a sodium chloride solution molarity of 0.462.