[Radioimmunodetection of colorectal cancer, using anti-CEA monoclonal antibody CEA 102: whole IgG versus F(ab')2 fragments]

In order to improve cancer imaging with radiolabeled antibodies, three factors appeared to be of particular importance: (1) The selection of the most favorable monoclonal antibody directed to tumor-associated antigen. (2) The use of F(ab')2 or Fab fragments. (3) Selection of the most convenient isotope. Monoclonal antibody CEA 102 was produced by immunization by purified CEA, and its F(ab')2 fragments were compared with whole IgG as a radiotracer for radioimmunodetection of the colorectal cancer. Fragments were eliminated from the circulation twice as fast as whole IgG, and tumor-to-background ratio was achieved more than 1 at 2-3 days with F(ab')2, but 6-7 days with whole IgG in tumor bearing nude mice. In clinical study, F(ab')2 demonstrated clear image on the 1 at day after injection, whereas achievement of the image was possible on the 3rd day in whole IgG. These results indicated that fragments are preferred over whole IgG. Therefore fragments make it possible to preclude dual isotope subtraction methods, and omit the long delays before imaging. They also make it possible to use short half life radionuclides with excellent photon properties, such as 123I and 99mTc.

Tumor-specific binding of radiolabeled G-22 monoclonal antibody in glioma patients

Iodine-131-labeled G-22 monoclonal antibody F(ab')2 fragment reaching specifically with a glioma-associated surface glycoprotein was administered to 12 glioma patients to investigate its use in radioimaging of intracranial gliomas. No immediate or delayed side effects were attributable to antibody injection. Nine patients received the radiolabeled complex intravenously. The images of low-grade gliomas were generally poor and disappeared within 4 days. High-contrast images were obtained beyond the 7th day in high-grade gliomas except one case in the pineal region. Three patients received intraventricular or intratumoral administration. Clear images of all tumors were demonstrated from the 2nd until later than the 7th day. One patient with cerebrospinal fluid (CSF) dissemination of brainstem glioma demonstrated negative CSF cytology after intraventricular administration.

Esophageal stenting with a self-expandable metallic device: a preliminary study

This study was designed to investigate the potential of the Gianturco-Rosch Z stent in the alimentary canal, using the rabbit esophagus as the animal model. Single stents were implanted in four animals, which were followed up for predetermined periods, lasting from 48 hours to 6 weeks. All the stents remained in place. A florid tissue reaction was noticed, initially manifesting primarily as submucosal cellular infiltration, and mucosal erosion. Over the ensuing six weeks, the acute changes gave way to mucosal regeneration, and the appearance of granulation tissue in the submucosa. The stented segments remained patent, and feeding difficulties were limited to the immediate post-procedure period. These preliminary results suggest that peristaltic activity is no contraindication to the use of Z stents, though measures to limit the tissue response need to be identified.

Recurrent rectal cancer and scar: differentiation with PET and MR imaging

The value of positron emission tomography (PET) and magnetic resonance (MR) imaging in differentiating recurrent rectal cancer and scar was investigated. PET with fluorine-18 2-fluoro-2-deoxy-D-glucose (FDG) and MR imaging were performed in 15 patients with suspected recurrence. FDG accumulation in the mass was measured by means of the differential absorption ratio (DAR). All 11 patients with confirmed recurrent rectal cancer had increased accumulation of FDG in the mass (DAR = 4.73 +/- 2.28). Low FDG accumulation in the mass (DAR = 0.97 +/- 0.15) was noted in the remaining four patients, in whom the presence of a scar was proved by means of follow-up observation with or without biopsy. On the MR images, the recurrent tumor could be differentiated from scar in all but one case. The lesion-muscle signal intensity ratios on the T2-weighted images for the recurrent tumor and scar were 2.18 +/- 0.55 and 0.89 +/- 0.30, respectively. PET and MR imaging complement each other in the differential diagnosis between recurrent rectal cancer and scar. PET may also permit the evaluation of the effect of therapy.

[Time-dose relationship of erythema in high energy photon irradiation therapy]

Skin doses of 100 patients who were treated with high energy ionizing irradiation during conventional irradiation therapy were measured by thermoluminescence dosimeter (TLD). In 87 of the 100 patients, acute hyperemic change of the skin (erythema) of the irradiated region was observed. In the other 13 patients, alopecia of the scalp was observed. The following conclusions were reached. 1) The time-dose relationship was linear when erythema tolerance was used as an index, but not when alopecia was used. 2) The tolerance dose for erythema was lower than previously reported. The slope of the isoeffect curve on the log-log plot of total absorbed skin dose against total number of days after the first irradiation was 0.68 when erythema was used as an index. This number is larger than previously reported results. We considered that erythema is significantly influenced by fraction size and that hyperfractionation is a promising method of irradiation, especially in Japan. 3) Combined use of chemotherapeutic agents, such as 5-Fu, accelerated erythema. The slope of combined treatment was 0.86. Observing acute hyperemic change of skin is considered to be a useful method of investigating the combined effects of chemotherapeutic agents on irradiation.

Hepatocellular carcinoma: evaluation with color Doppler US and MR imaging

Fifteen patients with hepatocellular carcinoma underwent examination with color Doppler ultrasound (US), magnetic resonance (MR) imaging, dynamic computed tomography (CT), and angiography. Doppler signals ranging from 0.22 to 3.48 kHz could be obtained from within the tumor in 14 of 15 patients. The resistive index was 0.38-0.77. Color Doppler signals were visualized in nine of 15 lesions with a Doppler shift greater than 0.7 kHz. The Doppler signals and the resistive index of the tumor vessels became lower as the vessels progressed into the center of the lesion. The appearance of tumor vessels recognized on MR images obtained with gradient-recalled acquisition in the steady state (GRASS) in 11 of 15 lesions was compared with that on CT scans and angiograms. Tumors that were hyperintense on GRASS images obtained with a flip angle of 15 degrees transmitted Doppler signals of considerably higher amplitude compared with the isointense lesions. Both color Doppler US and MR imaging provided useful information for characterizing intratumoral blood flow.

Comparison of Tc-99m HMPAO fast SPECT with Tc-99m HMPAO conventional SPECT in patients with acute stroke

Tc-99m HMPAO SPECT is more likely to detect a stroke in early stages than CT. However, a conventional HMPAO SPECT study takes at least 30 minutes to complete. This paper compares fast Tc-99m HMPAO SPECT scans and conventional Tc-99m HMPAO SPECT scans with respect to spatial resolution and diagnostic efficacy in vitro and in a small series of patients, respectively. The spatial resolution of fast Tc-99m HMPAO SPECT did not match that of images obtained from conventional SPECT, though the difference proved to be of no clinical significance. Since fast SPECT requires only one-fourth to one-fifth the time necessary for conventional SPECT, it may be more suitable for investigating cases of acute stroke in critical clinical situations.

[Diagnostic accuracy of breast sonography. Comparison among three different techniques]

Mechanical arc scanning is widely used for breast sonography in Japan. The authors have used three different kinds of devices over the past seven years. The diagnostic accuracy was compared among three groups of patients with pathologically confirmed breast masses. In group A, 309 cases (77 carcinomas) were evaluated with a 10 MHz contact compound scanner, and the sensitivity, specificity and accuracy rates were 77.9%, 97.8% and 92.9%, respectively. In group B, 306 cases (56 carcinomas) were evaluated with a 5 or 7.5 MHz mechanical arc scanner, and the sensitivity, specificity and accuracy rates were 89.3%, 84.8% and 85.6%, respectively. In group C, 296 cases (71 carcinomas) were evaluated with a 7.5 MHz real time scanner, and the sensitivity, specificity and accuracy rates were 95.8%, 92.4% and 93.2%, respectively. In cases with T1 breast cancer, the methods had sensitivities of 60.0%, 85.7% and 94.5%, respectively. The sensitivity of the real-time scanner was not significantly different from that of the mechanical arc scanner. In conclusion, the hand-held real-time scanner with high-frequency transducer is a simple, useful device with high diagnostic accuracy for breast examination and can be used as a substitute for the mechanical arc scanner.

[A new database system for radiological reports]

We have designed and developed a new database system to facilitate automatic feedback of the content of radiology reports to radiologists. The prototype of this database system has been implemented in the RGSS-IDJ, a developmental computer system that applies artificial intelligence methods to a reporting system. This prototype system was constructed to test the feasibility of overcoming the limitations of conventional database systems. The new database system is based on our semantic model for radiology reports and is able to treat data with unnormalized relations. Operations specific to our database system include the ability to acquire information about a set of reports that contains any semantic expression included in the lexicon and the ability to obtain the expressions that belong to a set of several semantic expressions in the reports. Thus, our new database system will offer a more powerful tool for analyzing the content of reports than conventional database systems.

[Stereotactic irradiation using a linear accelerator with helmet-type shell]

A new method is proposed for external stereotactic and three-dimensional irradiation for a small target in the skull. In this method, we use a special long tube collimator, helmet-type shell (guiding rods are attached to the shell using the CT-stereotactic apparatus) and 10 MV linear accelerator. The patient's head is fixed conservatively by the helmet-type shell. In the phantom experiment, the 90% isodose area was 10 mm in diameter, and the error between the geometrical center of the target and the irradiated center was 2 mm.

Ultrasonographic and thermographic evaluation of the lower limb after transfemoral catheterization

Ten adults undergoing routine transfemoral catheterization were randomly selected for study. Ultrasonography and thermography were performed within 48 hours before and after the catheterization procedure. Sites proximal and distal to puncture were assessed. There were no angiographic procedural complications in any case. Distal to the puncture, Doppler evaluation revealed a decrease in peak systolic velocity (PSV) in six cases, with four showing a greater than 30% fall, while three of the four cases with an increase had a less than 10% rise in PSV. Findings at the proximal site showed no distinct pattern. Changes in the resistive index at both sites were minimal. There was a significant increase in turbulence distal to the site of puncture in six cases. B-mode revealed arterial wall thickening compromising the lumen in half the cases. Thermography was done in four cases, and there was a tendency for an increase in limb temperature after the catheterization procedure. In view of the above-mentioned findings seen in "normal, uncomplicated" procedures, a larger study appears warranted to assess the significance of these findings and to attempt a correlation of the above results with the angiographic procedure.

Effects of Fe2+, Fe3+ and desferrioxamine on paraquat accumulation by rabbit kidney cortex slices

Effects of Fe2+, Fe3+ and desferrioxamine (DFO) on the accumulation of paraquat (PQ) into rabbit kidney cortical slices were studied. Fe3+ showed dose-dependent inhibition of PQ accumulation. Fe2+ had a more powerful stimulatory effect on the lipid peroxidation of cortical slices than Fe3+, but it did not reduce PQ accumulation. The addition of DFO made the inhibitory effect of Fe3+ on PQ accumulation more pronounced. These results suggest that Fe3+ is able to inhibit the accumulation of PQ independent of its peroxidative action, and that Fe(3+)-desferrioxamine (ferrioxamine) may serve as an antidote for the toxicity of PQ.

[Intraoperative lumbar injection of Ringer's solution for surgical treatment of chronic subdural hematomas]

A series of 64 patients underwent surgical treatment for chronic subdural hematomas between 1980 and 1989. The procedure consisted of a single burr-hole, irrigation of the hematoma without subdural drainage and lumbar intrathecal injection of Ringer's solution. Irrigation was carried out until the washing was clear and the injection was continued until the brain was in contact with the edge of the burr-hole. Excellent outcome was achieved in 53 patients (82.8% of the total). Two of the patients died, thus making a 3.1% mortality rate. Such complications as tension pneumocephalus and intracerebral hematoma were not observed and no patient had a recurrence.

Evidence that the tyrosine kinase domain of a small fraction of epidermal growth factor receptor molecules is exposed on the outer surface of A431 cells

Intact A431 cells were labeled with [gamma-32P]ATP. The major phosphorylation product of the ecto-kinase activity of A431 cells had the molecular mass of 170 kd and was identified as EGF receptor by specific immunoprecipitation. This phosphorylation was not stimulated by EGF added to the reaction buffer, but replacement of MgCl2 by MnCl2 in the buffer remarkably stimulated phosphorylation. An exogenous protein substrate, alpha-casein, was also phosphorylated by intact A431 cells. The analyses for phospho-amino acids of both EGF receptor and alpha-casein revealed that phosphorylation occurred mainly at phosphotyrosine residues. Tryptic phospho-peptides of the EGF receptor of intact A431 cells labeled with [gamma-32P]ATP were fractionated by HPLC. The elution patterns were essentially the same as that of the autophosphorylated EGF receptor, indicating that the phosphorylation sites of EGF receptor labeled in vivo with [gamma-32P]ATP are located in three tyrosine residues in the carboxyl terminus. These results indicate that the carboxyl-terminal tyrosine kinase domain of a small fraction of the EGF receptor molecules of an A431 cell is exposed on the outer surface of the cells.

Site-specific stable insertion into the human cytomegalovirus genome of a foreign gene under control of the SV40 promoter

On the basis of a previous finding that the 7.8-kb HindIII-O fragment of the human cytomegalovirus strain Towne genome is nonessential for viral replication, we constructed a vector, pKM, that directs introduction of foreign genes by homologous recombination precisely replacing the O fragment. Using this vector, we constructed Towne-strain-derived recombinant virus in which a chimeric lacZ gene fused to the simian virus 40 promoter and a poly(A) signal were inserted in place of the O fragment. Two types of recombinants were obtained which carried the chimeric gene in opposite directions, beta-Galactosidase (beta Gal) was produced throughout the infection cycle in human embryonic lung cells infected with these recombinants, and the rate of its synthesis in the early stages of infection was comparable to that of synthesis of a 65-kDa viral glycoprotein, one of the abundantly produced viral proteins. The chimeric lacZ gene introduced was stable and no lacZ- revertants have been observed so far.

Fastidious human adenovirus type 40 can propagate efficiently and produce plaques on a human cell line, A549, derived from lung carcinoma

Human adenovirus type 40 (Ad40) cannot propagate in conventional established human cell lines such as KB or HeLa cells. However, it has been shown that Ad40 DNA replicates in KB18 cells which express Ad2 E1B genes, suggesting that Ad40 is defective in the E1B gene function in KB or HeLa cells. We show here that Ad40 can propagate and produce plaques on A549 cells which do not contain Ad E1B genes. Our experiments show that the levels of replication of Ad40 DNA and production of infectious Ad40 virus in A549 cells are the same as or higher than those in 293 or KB18 cells. Dot blot analysis shows that the levels of Ad40 E1A and E1B mRNAs expressed in A549 cells at early to intermediate times postinfection are at least 10-fold higher than those in KB or KB18 cells. Northern (RNA) blot analysis shows that large E1B mRNA species (approximately 24S to 26S) are synthesized prior to the onset of DNA replication in A549 cells. No E1B mRNA species are synthesized in KB or KB18 cells at early times postinfection, and no differences in the expression of E1B mRNAs are seen between KB and KB18 cells. The experiment suggests that A549 cells have a cellular factor(s) which activates Ad40 E1B mRNA synthesis and that the E1B mRNA synthesis helps Ad40 propagation. In contrast, Ad40 can propagate in KB18 cells by using Ad2 E1B gene products that are constitutively expressed in this cell line. Furthermore, this result shows that Ad40 cannot propagate in KB cells because of the failure in the expression of E1B genes at early times postinfection.

Stimulation of prostaglandin synthesis in rabbit gastric antral mucosal slices by desferrioxamine in vitro

Desferrioxamine is an iron-chelating agent used in the treatment of iron overload. It is a powerful inhibitor of iron-dependent radical reactions. The effect of desferrioxamine of prostaglandin (PG) synthesis and metabolism in rabbit gastric antral mucosal slices has been examined. Desferrioxamine significantly enhanced the production of PGE2 and PGF2 alpha. The formation of 13,14-dihydro-15-keto PGE2 and 13,14-dihydro-15-keto PGF2 alpha was also increased slightly by desferrioxamine. The addition of Fe3+ or Al3+ blocked the stimulatory action of desferrioxamine on PGE2 and PGF2 alpha production. Desferrioxamine appears to be stimulating the activity of PG cyclooxygenase through the removal of endogenous antral mucosal iron. These results suggest that desferrioxamine has the potential to increase the PG levels in gastric mucosa by primarily stimulating PG biosynthesis. The possibility that desferrioxamine may be of therapeutic value in the treatment of ischemic injury in the stomach is discussed.

Triacylglycerol lipase mediated release of arachidonic acid for prostaglandin synthesis in rabbit kidney medulla microsomes

The effect of triarachidonin on the synthesis of prostaglandins in rabbit kidney medulla microsomes was examined. Medulla microsomes were incubated with triarachidonin in 0.1 M--Tris/HCl buffer (pH 7.0) containing reduced glutathione and hydroquinone and the formed prostaglandin E2, prostaglandin F2 alpha and prostaglandin D2 were measured by high-pressure liquid chromatography using 9-anthryldiazomethane for derivatization. The addition of triarachidonin (1-10 microM) stimulated prostaglandin formation in a dose-dependent manner. Under our incubation conditions rabbit kidney medulla was found to produce prostaglandin E2 mainly. When arachidonic acid, instead of triarachidonin, was added to the incubation mixture of microsomes, the identical profile of prostaglandin products was obtained. When the pH of the reaction mixture was changed from 7.0 to 8.0, the rate of triarachidonin-induced prostaglandin E2 formation was approximately 60% of that observed at pH 7.0. Studies utilizing Ca2+ and EGTA revealed that triacylglycerol lipase of kidney medulla is independent of Ca2+. The addition of epinephrine made the stimulatory effect of triarachidonin on prostaglandin E2 formation more pronounced. These results suggest that epinephrine-activated triacylglycerol lipase is present in the renomedullary microsomes, and this enzyme activity is a potential mediator of release of arachidonic acid for prostaglandin synthesis in the kidney medulla.

[Arterial embolization therapy for metastatic bone and soft-tissue tumors with microcatheter and microcoils]

Transcatheter arterial embolization therapy was performed in fifteen patients with hypervascular metastatic bone and soft-tissue tumors (7 from renal carcinoma, 5 from hepatocellular carcinoma, and one each from breast, thyroid, and cholangiocarcinoma). Sites of metastasis were spine (7), pelvis (5), skull (2), paraspine (2), chest wall (1), and thigh (1). Five patients had not responded to previous radiation therapy and hyperthermia. Embolization of feeding arteries was performed superselectively with long tapered catheters or coaxial microcatheters. Emulsion of Lipiodol and anticancer agent, polyvinyl alcohol sponge, gelatin sponge, and microcoils were used as embolic materials in various combinations. Relief of pain was experienced in 14 of 15 patients. Two patients were operated following embolization with minimal blood loss. Change in tumor size was evaluated by CT or MRI in ten patients. Reduction of tumor size were more than 50% in five patients, from 25% to 50% in two, and no change in three patients. Especially, patients embolized with microcatheter and microcoils showed excellent long-term results. No serious complications were seen. In conclusion, superselective arterial embolization therapy with coaxial microcatheter and microcoils was proved to be an useful treatment for hypervascular metastatic bone and soft-tissue tumors.

[MR imaging of the vestibular aqueduct in normal volunteers and patients with Menière's disease--a preliminary report]

In this paper we attempted MR visualization of the vestibular aqueduct (VA) with a surface coil. Sagittal plane was most preferable from the result of preliminary study using a dry temporal bone. In all of ten normal volunteers, VAs were visualized well. In none of them, proton-density weighted spin-echo (SE) images were inferior to both T1- and T2-weighted SE image. In four of eight patients with Menière's disease, VAs were not visualized due to obstruction of VA, although in all of ten non-Menière's patients with hearing loss or vertigo, VAs were well visualized. Although further investigation is needed, MR imaging of VA including both its content and surrounding bony structure would give important information to manage the patients with either Menière's disease or other disorders of internal ears.

[The development of a distribution system for medical lasers and its clinical application]

We developed a new laser beam generator system which can deliver laser beam to multiple terminals in distant clinical therapy rooms. The system possesses the distribution equipment by which Nd-YAG laser power is distributed to 8 output terminals under the computer control. Distributed laser beam is delivered to each distant terminal with clinical informations through the optical fiber. In the fundamental studies, possibility of distant transportation of laser beam (30 m) only with 10% loss of energy and without dangerous heating at the connection parts was shown. There seems to be no disadvantage associated with distribution laser beam. In the clinical study, the system was applied to five patients with the symptoms including hemosputum, esophageal stenosis, hemorrhage, lip ulcer and pain. Clinical usefulness of the system was proved. The advantages of the system are as follows: 1. Benefit of cost reduction due to multiple use of single laser source. 2. No necessity of transport of the equipment. 3. No requirement of a wide space to install the equipment in the distant room. 4. Efficient management and maintenance of the system by centralization. Further improvements, e.g., simultaneous use at multiple terminals and elongation of transportation up to 340 m, make the system more useful for clinical application.