Radiosensitization of two murine fibrosarcomas with 6-thioguanine

In Vivo murine tumor experiments were carried out to determine whether 6-thioguanine (6-TG) could enhance the cytotoxic effects of radiation on tumors. The combined effects of single and fractionated x-irradiation were evaluated on the transplanted methylcholanthrene induced fibrosarcoma (Meth-A) in BALB/c mice, a moderately radioresponsive tumor and on the radiation induced fibrosarcoma (RIF) in C3H/He mice, a highly radioresistant tumor. The combined treatment of single administration of 6-TG (25 mg/kg) and of x-irradiation (20 Gy) on Meth-A tumors produced more than 90% tumor control, whereas the radiation alone resulted in less than 5% tumor control. The radiosensitizing effect by 6-TG was higher when the drug was administered either 1 to 8 hr prior to or 24 hr after x-irradiation. The dose modification factor of single dose 6-TG (10 mg/kg) is estimated to be 1.47 for Meth-A tumor and 1.25 for RIF tumor. The tumor control rates of fractionated irradiation alone and with concomitant 6-TG in Meth-A tumors were 14% and 59%, respectively. Based on the studies reported here and well documented pharmacokinetics in humans, it is suggested that combined radiation therapy and 6-TG may provide an enhanced therapeutic effect even in tumor varieties where the drug has no apparent anti-tumor activity on non-irradiated cells.

Molecular switch for signal transduction: structural differences between active and inactive forms of protooncogenic ras proteins

Ras proteins participate as a molecular switch in the early steps of the signal transduction pathway that is associated with cell growth and differentiation. When the protein is in its GTP complexed form it is active in signal transduction, whereas it is inactive in its GDP complexed form. A comparison of eight three-dimensional structures of ras proteins in four different crystal lattices, five with a nonhydrolyzable GTP analog and three with GDP, reveals that the "on" and "off" states of the switch are distinguished by conformational differences that span a length of more than 40 A, and are induced by the gamma-phosphate. The most significant differences are localized in two regions: residues 30 to 38 (the switch I region) in the second loop and residues 60 to 76 (the switch II region) consisting of the fourth loop and the short alpha-helix that follows the loop. Both regions are highly exposed and form a continuous strip on the molecular surface most likely to be the recognition sites for the effector and receptor molecule(or molecules). The conformational differences also provide a structural basis for understanding the biological and biochemical changes of the proteins due to oncogenic mutations, autophosphorylation, and GTP hydrolysis, and for understanding the interactions with other proteins.

Magnetic susceptibility effects of trabecular bone on magnetic resonance imaging of bone marrow

High-field spectroscopic studies at 5.88 tesla (T) indicate significant T2* shortening of water in suspensions of powdered bone, interpreted to be a result of magnetic susceptibility differences between bone particles and water. The authors investigated the effects of magnetic susceptibility differences between trabecular bone and water on magnetic resonance (MR) images at 0.6 T. The phantom was constructed of macerated intact trabecular human bone immersed in water. Although susceptibility-induced magnetic field inhomogeneities were detected by spectral line broadening by using an asymmetric spin-echo technique, the results show only a modest T2* shortening at this field strength. As expected, no T1 effect of trabecular bone was observed. Although susceptibility effects of trabecular bone may have a small impact on the signal intensity of MR images of bone marrow at midfield strength, the observed field strength dependence of these effects would predict significant susceptibility effects on clinical images at higher field strength.

Desmethionine alkylamide bombesin analogues: a new class of bombesin receptor antagonists with potent antisecretory activity in pancreatic acini and antimitotic activity in Swiss 3T3 cells

Bombesin-related peptides have a large number of physiological functions as well as having an autocrine growth mechanism for the regulation of small cell lung cancer cells. In the present study we have synthesized 21 des-Met amide or alkylamide analogues of bombesin and compared their abilities to function as bombesin receptor antagonists in guinea pig pancreatic acini and Swiss 3T3 cells with those of the previously most potent antagonist described, [Leu13 psi(CH2NH)Leu14]bombesin (analogue I). All des-Met analogues functioned as antagonists. Bn(1-13)NH2 was approximately equipotent to I (Ki = 60-80 nM) whereas Bn(6-13)NH2 was 30-fold less potent (Ki = 1800 nM). Formation of an ethylamide, Bn(6-13)ethylamide, increased the potency 30-fold such that this octapeptide was equipotent to I. The addition of a D-Phe6 moiety to I did not change potency but caused a 30-fold increase in potency of Bn(6-13)NH2 and a 8-fold increase in the potency of Bn(6-13)ethylamide (Ki = 16 nM). Additional studies of both NH2- and COOH-terminal alterations in Bn(6-13)NH2 demonstrated that the most potent antagonist was [D-Phe6]Bn(6-13)propylamide (PA), having IC50's of 1.6 nM and 0.8 nM for bombesin-stimulated amylase release and Swiss 3T3 cell growth, respectively. Detailed studies of the most potent amide analogue, [D-Phe6]Bn(6-13)NH2, and alkylamide analogue, [D-Phe6]Bn(6-13)PA, demonstrated that these analogues functioned as competitive antagonists and that their action was selective for the bombesin receptor. These results demonstrate that, as with CCK- and gastrin-related peptides, the C-terminal amino acid is important for initiating a biologic response but not essential for determining receptor affinity.(ABSTRACT TRUNCATED AT 250 WORDS)

Atomic charges for DNA constituents derived from single-crystal X-ray diffraction data

We have derived a complete set of atomic charges for DNA from very high resolution, low temperature, single-crystal X-ray diffraction data, collected for a variety of nucleosides and nucleotides: cytidine; deoxycytidine 5'-monophosphate; deoxythymidine; guanosine 5'-monophosphate; deoxyadenosine; adenosine. This set of charges represents the first experimentally based parameterization of an important term in the energy function used in most modeling of DNA. The resulting charges are in good agreement with chemical intuition and experimental observations. They also agree qualitatively with the theoretically derived values now commonly used, but numerous and significant quantitative differences are observed. Possible reasons for the quantitative disagreement are discussed. An averaged set of charges (derived from the experimental results), which can be used in DNA modeling calculations, is presented.

Presence of immunoreactive atrial natriuretic peptides in pericardial fluid of human subjects with congenital heart diseases

The epicardial release of immunoreactive atrial natriuretic peptides (ir-ANPs) in inside-out perfused rabbit atria has been reported. In order to determine the presence of ir-ANPs in pericardial fluid and to evaluate their biochemical characteristics, we measured the concentration of ir-ANPs in pericardial fluid obtained from the patients with congenital heart diseases during open heart surgery. Serial dilution curves made with the extrats of pericardial fluid using Sep-Pak C18 cartridges were parallel with standard curve. The concentration of ir-ANPs in pericardial fluid was significantly lower than the corresponding plasma concentration. On gel permeation and reverse-phase high performance liquid chromatography, the ir-ANPs in pericardial fluid, plasma and atrial appendage showed both high and low molecular weights. The major peak of ir-ANPs in plasma was observed at the corresponding fraction to the alpha-human ANP and considerable amount of high molecular weight form of ir-ANPs was observed in pericardial fluid. However, the major peak of ir-ANPs in atrial appendage was observed at the corresponding fraction to the rat pro-ANP. The data suggest that ir-ANPs exist both high and low molecular weight forms in pericardial fluid.

Stereotactic transplantation of adrenal medullary tissue in Parkinson's disease

Autograft of adrenal medullary tissue into the striatum was performed stereotactically in 5 patients with severe Parkinson's disease. Two patients had suffered from side effects of L-dopa, and 3 were severely disabled without L-dopa preoperatively. After surgery, the dosage of L-dopa could be reduced in 1, and L-dopa could be withdrawn in 4 patients. The results of adrenal medullary tissue transplantation in Parkinson's disease are analyzed.

Three-dimensional computer simulation of stereotactic surgery

Software which can be used to simulate stereotactic surgery on a personal computer was developed. Using the modified Todd-Wells frame coordinates, it can reconstruct a three-dimensional image of the brain structure and simulate the target trajectories before the operation. Also, it can calculate the volume of the target region and the distance between the target and certain points in arbitrary trajectory angles. Its optional mode can be used for simulation of conventional brain surgery for previewing deep-seated brain lesions in the operating position.

Caroli disease: central dot sign in CT

Two adults with communicating cavernous ectasia of the biliary tract (Caroli disease) are described. Both patients had the pure form of the disease, characterized by saccular dilatation of intrahepatic bile ducts, multiple intrahepatic calculi, absence of portal hypertension, and associated cystic renal disease. Computed tomographic (CT) scans of the liver showed tiny dots with strong contrast enhancement within dilated intrahepatic bile ducts (the central dot sign). These intraluminal dots on CT scans corresponded to intraluminal portal veins on sonograms, findings indicating portal radicles surrounded by dilated intrahepatic bile ducts.

Familial superior mesenteric artery syndrome

Five members of a family of eight, including the father and four daughters, presented with symptoms previously attributed to the superior mesenteric artery syndrome. The four daughters also had radiographic studies supporting that diagnosis. This familial clustering raises the possibility of a genetic predisposition to this symptom and radiographic complex.

Phytochrome induces changes in the immunodetectable level of a wall peroxidase that precede growth changes in maize seedlings

The regulatory pigment phytochrome induces rapid and opposite growth changes in different regions of etiolated maize seedlings: it stimulates the elongation rate of coleoptiles and inhibits that of mesocotyls. As measured by a quantitative immunoassay, phytochrome also promotes rapid and opposite changes in the extractable content of a Mr 98,000 anionic isoperoxidase in the cell walls of these same organs: it induces a decrease of this peroxidase in coleoptiles and an increase in mesocotyls. The peroxidase changes precede the growth changes. As measured by video stereomicroscopy or a position transducer, red light (R), which photoactivates phytochrome, stimulates coleoptile elongation with a lag of about 15-20 min and suppresses mesocotyl growth with a lag of 45-50 min. R also induces a 50% reduction in the extractable level of the anionic peroxidase in coleoptile walls in less than 10 min and a 40% increase in the level of this peroxidase in mesocotyl walls within 30 min. Ascorbic acid, an inhibitor of peroxidase activity, blocks the effects of R on mesocotyl section growth. These results are relevant to hypotheses that postulate that certain wall peroxidases can participate in light-induced changes in growth rate by their effects on wall extensibility.

Inactivation of potato lipoxygenase by hydroperoxy acids as suicide substrates

The preincubation of potato lipoxygenase with 9(S)-hydroperoxyoctadecatrienoic acid, 15(S)-hydroperoxyeicosatetraenoic acid or 5(S)-hydroperoxyeicosatetraenoic acid which can be subjected to further lipoxygenation led to the gradual inactivation of the lipoxygenase activity, whereas 13(S)-hydroperoxy-9,13,15-octadecatrienoic acid or 15(S)-hydroperoxy-11,13,17-eicosatrienoic acid had no significant effect. The inhibitory effect of the peroxy acids was abolished by hemoglobin. Based on these observations, it is proposed that the unstable epoxide intermediates from the respective peroxy acids may be responsible for the inactivation of potato lipoxygenase. In the comparative study, it was found that 15(S)-hydroperoxyeicosatetraenoic acid possessed more effective inhibitory role than the other acids with Ki value of 250 microM.

MR imaging of retroperitoneal teratoma: correlation with CT and pathology

A retroperitoneal teratoma was studied with CT and magnetic resonance (MR) imaging. The images were correlated with the pathologic findings. The tumor was composed of five portions: adipose tissue, bone, hair, sebum, and loose edematous fibrofatty tissue with skin. Computed tomography and MR both demonstrated a well defined mass with separate cystic and solid components and all five tissue elements of the tumor. Magnetic resonance was superior to CT in delineating the relationship of blood vessels to the tumor.

Takayasu arteritis: angiographic findings and results of angioplasty

Takayasu arteritis is a systemic disease characterized by occlusion of the aorta and its branches. We performed coronary angiography and thoracic and abdominal aortography on 47 patients with Takayasu arteritis. Angiographic findings included arterial stenosis, occlusion, or aneurysm. The left subclavian artery was involved in 26 cases (55%), the abdominal aorta in 25 cases (53%), the right renal artery in 21 cases (45%), the right subclavian and left renal arteries in 18 cases (38%), the descending thoracic aorta in 15 cases (32%), and the left common carotid artery in 14 cases (30%). The coronary arteriograms in the 47 patients showed coronary involvement in seven (15%). Proximal or osteal lesions were present in six cases. Percutaneous transluminal angioplasty was performed successfully in eight patients for treatment of three aortic lesions, nine renal artery lesions, one subclavian artery lesion, and one coronary artery lesion. In the three cases with recurrence after 4-7 months, repeated angioplasty was successful. For appropriate management of Takayasu arteritis, we suggest thorough angiographic evaluation and proper intervention, including percutaneous transluminal angioplasty in selected cases for revascularization.

Small hepatocellular carcinoma: detection with sonography, computed tomography (CT), angiography and Lipiodol-CT

Seventy-three small hepatocellular carcinomas under 5 cm in diameter in 47 patients were examined by sonography, computed tomography (CT), hepatic angiography and CT after intra-arterial injection of iodized poppy-seed oil (Lipiodol-CT). The imaging techniques that first led to detection of small hepatocellular carcinomas were sonography in 53 cases (72.6%), CT in 10 (13.7%), angiography in eight (11%) and Lipiodol-CT in two (2.7%). Sensitivity for detecting small hepatocellular carcinomas was 73% with sonography, 82% with CT, 86% with angiography and 96% with Lipiodol-CT. As a screening method, sonographic and CT results in detecting small hepatocellular carcinomas were not significantly different (p greater than 0.05). Lipiodol-CT was superior to sonography (p less than 0.01), CT (p less than 0.01) and angiography (p less than 0.05) in detecting small hepatocellular carcinomas. We believe that the combined use of Lipiodol-CT with screening methods such as sonography or CT is indispensable for the accurate detection of small hepatocellular carcinomas.

Trigeminal neurinomas: operative approach in eight cases

The authors report eight cases of trigeminal neurinoma managed over the past 13 years with radical resection at a single-stage operation. Three patients were male and five were female, ranging in age from 25 to 56 years (mean 41.5 years). One had von Recklinghausen's disease. The tumors were located mainly within the middle fossa in two cases and within the posterior fossa in two, and extended both supra-and infratentorially in four cases. Facial pain and hearing disturbance were the main symptoms, with various other symptoms such as focal seizures, hemiparesis, gait disturbance, increased intracranial pressure, and visual disturbance also being noted. All patients underwent radical tumor resection with either a transpetrosal transtentorial or orbitozygomatic infratemporal surgical approach; the approach depended on the topography of the tumor. Total removal was performed in all cases. Only one patient, treated early in the series, required a second operation to remove the tumor completely. In another case the tumor recurred 5 years after the operation. There has been no operative mortality, but injury or permanent damage to the trigeminal branches was inevitable in many cases. The surgical results were excellent in three patients and good in five.

Short-chain pseudopeptide bombesin receptor antagonists with enhanced binding affinities for pancreatic acinar and Swiss 3T3 cells display strong antimitotic activity

The high inhibitory potency of the previously developed bombesin antagonist [Leu13, psi CH2NHLeu14]bombesin (analogue I) (IC50 values of 30 and 18 nM for inhibition of bombesin-stimulated amylase secretion from guinea pig acinar cells and Swiss 3T3 cell growth, respectively) diminished considerably when shorter chain lengths were examined. For instance, [Leu13, psi CH2NHLeu14]bombesin-(5-14),[Leu13, psi CH2NHLeu14] bombesin-(6-14), and [Leu9, psi CH2NHLeu10]neuromedin C had IC50 values of 150, 150, and 280 nM, respectively. Incorporation of a D-Phe residue at position 6 of [Leu13, psi CH2NHLeu14] bombesin did not significantly change the various biological parameters. However, its presence in [Leu13, psi CH2NHLeu14]bombesin-(6-14) and at position 2 of psi-neuromedin C-(2-10) resulted in about 10-fold increases in potency up to and above that of the original antagonist. For instance, [D-Phe6,Leu13,psi CH2NHLeu14]bombesin-(6-14) and des-Gly1-[D-Phe2,Leu9,psi CH2NHLeu10]neuromedin C exhibited IC50 values of 5 and 28 nM, respectively. Analogues based on the litorin sequence which contains an NH2-terminal pyroglutamic acid residue at the bombesin position 6 equivalent were also quite potent. The ability of various analogues to interact with bombesin receptors on pancreatic acini correlated reasonably well with potencies derived from inhibition of bombesin-stimulated growth of Swiss 3T3 cells. Additional studies of NH2- and COOH-terminal structure-activity relationships resulted in the synthesis of [D-Phe6,Leu13,psi CH2NHPhe14]bombesin-(6-14), which was particularly effective in inhibiting 3T3 cell growth at high picomolar concentrations (IC50 = 0.72 nM and Ki = 3.1 nM for 3T3 cells; IC50 = 7.5 nM and Ki = 9.9 nM for acini). Detailed investigations with one of the most potent antagonists, [D-Phe6,Leu13,psi CH2NHLeu14]bombesin-(6-14) (Ki = 14 nM for acini cells and 7.1 for 3T3 cells), demonstrated that this analogue was a competitive inhibitor of bombesin and that this activity was specific for the bombesin receptor. Thus, inhibitory potencies have been improved generally up to 25 times over previously reported structures; and, given that bombesin itself has a Ki of 1.2 nM for 3T3 cell binding, some of these analogues are extraordinarily high affinity receptor antagonists. They can also be synthesized more readily and offer fewer proteolytic degradation sites than the original pseudopeptide and should be excellent candidates for in vivo studies aimed at inhibition of bombesin-dependent human small cell lung carcinoma growth.

Hilar cholangiocarcinoma: comparative study with sonography and CT

Fifty-one patients were studied to determine the relative accuracy of sonography and computed tomography (CT) in the evaluation of hilar cholangiocarcinoma. Both sonography and CT permitted detection of intrahepatic bile duct dilatation in all patients. Nonunion of right and left intrahepatic bile ducts was identified with sonography in 90% and with CT in 94% of patients. The tumor per se was depicted by sonography in 21% and by CT in 40% of patients. Forty tumors (78%) were of the infiltrating type, seven (14%) were exophytic, and four (8%) were polypoid. With sonography, infiltrating and exophytic tumors were difficult to depict, whereas polypoid tumors were well identified. With CT, infiltrating tumors were more difficult to depict than were exophytic or polypoid tumors. On CT scans, depicted tumors of the infiltrating type showed high attenuation and an indistinct margin, whereas exophytic and polypoid tumors showed low attenuation and a well-defined margin. Sonography and CT were comparably accurate in determining the level of obstruction in hilar cholangiocarcinoma even when no mass was depicted. CT was superior to sonography in depicting tumor per se and in demonstrating associated findings.

Transrepression of the N-myc expression by c-myc protein

In the human neuroblastoma cell line IMR32 the N-myc gene happens to be amplified and actively expressed, whereas no stable c-myc RNA can be detected in the same cells. In this report, we show that in IMR32 cells the expression of the N-myc gene is repressed by introduction of a c-myc expression vector (c-myc cDNA conjugated with an SR promoter). Moreover, dose response experiments showed that the amount of endogenous c-myc protein present in HeLa cells (which express c-myc but not N-myc) is enough to repress the expression of N-myc in IMR32 cells.

Redesigning a sweet protein: increased stability and renaturability

Monellin is one of two natural proteins from African berries with potent sweet taste. Monellin is the smaller of the two, and consists of two peptides. The protein loses sweetness when heated above 50 degrees C under acidic pH. Based on the crystal structure of monellin we have fused the two chains into a single chain using several different linkers copied and 'transplanted' from the same molecule. One of the newly designed proteins is as potently sweet as the natural one, is more stable upon temperature or pH changes, and renatures easily even after heating to 100 degrees C at low pH.

Genetic and pharmacological suppression of oncogenic mutations in ras genes of yeast and humans

The activity of an oncoprotein and the secretion of a pheromone can be affected by an unusual protein modification. Specifically, posttranslational modification of yeast a-factor and Ras protein requires an intermediate of the cholesterol biosynthetic pathway. This modification is apparently essential for biological activity. Studies of yeast mutants blocked in sterol biosynthesis demonstrated that the membrane association and biological activation of the yeast Ras2 protein require mevalonate, a precursor of sterols and other isoprenes such as farnesyl pyrophosphate. Furthermore, drugs that inhibit mevalonate biosynthesis blocked the in vivo action of oncogenic derivatives of human Ras protein in the Xenopus oocyte assay. The same drugs and mutations also prevented the posttranslational processing and secretion of yeast a-factor, a peptide that is farnesylated. Thus, the mevalonate requirement for Ras activation may indicate that attachment of a mevalonate-derived (isoprenoid) moiety to Ras proteins is necessary for membrane association and biological function. These observations establish a connection between the cholesterol biosynthetic pathway and transformation by the ras oncogene and offer a novel pharmacological approach to investigating, and possibly controlling, ras-mediated malignant transformations.

Structure of ras proteins

In the Table of Contents of the 24 March 1989 issue, the title of the report "Histamine is an intracellular messenger mediating platelet aggregation" by S. P. Saxena et al. appearing on page 1596 was incorrectly printed.

Acute pancreatitis in a case of multiple myeloma with hypercalcemia

A patient with hypercalcemia and newly diagnosed multiple myeloma developed acute pancreatitis. Other etiologic factors for pancreatitis were excluded. Hypercalcemia secondary to hyperparathyroidism is associated with acute pancreatitis. In English literature, only one other case has been published where the hypercalcemia of multiple myeloma may have caused pancreatitis. Pancreatitis should be considered in patients with hypercalcemia and multiple myeloma who develop nausea/vomiting, and abdominal pain.

[The application of vascular endoscope for the extracranial cerebrovascular occlusive disease: the development of the endoscopic system]

Flexible thin fiber catheter is applied as vascular endoscope for occlusive lesions in the extracranial cerebral arteries. This fiber catheter is introduced transfemorally through 6 or 7 french-sized double lumen balloon catheters. Vascular endoscope clearly demonstrates the internal surface of these vessels by transient occlusion of the proximal side of the vessel through balloon inflation. The occlusive lesions in the subclavian artery or in the proximal vertebral artery were revealed as round smooth-surfaced mass to be treated by the percutaneous transluminal angioplasty.

Crystallization and preliminary X-ray studies of HisJ and LAO periplasmic proteins from Salmonella typhimurium

Two periplasmic binding proteins, HisJ and LAO, which are involved in histidine and arginine transport, respectively, have been crystallized. Preliminary X-ray diffraction studies of the HisJ and LAO crystals show that both belong to the orthorhombic space group P2(1)2(1)2(1) and have unit cell dimensions of a = 39.26 A, b = 66.17 A, c = 88.33 A and a = 36.08 A, b = 78.34 A, c = 102.02 A, respectively. Both HisJ and LAO crystals diffract beyond 2.0 A resolution.

Giant cavernous hemangioma of the liver: CT and MR imaging in 10 cases

Ten giant cavernous hemangiomas of the liver in eight patients were examined with both MR imaging and dynamic bolus CT. The maximal diameters of the tumors were 6.5-19 cm (mean, 10.8 cm). MR imaging was done with a 2.0-T superconducting magnet and spin-echo imaging. CT was done with single-bolus dynamic scans. On MR images, all 10 hemangiomas had a heterogeneous appearance. The main part of the tumor comprised uniform, well-defined, high-intensity areas on T2-weighted images, with increasing intensity ratios with prolongation of TR and TE. Other parts of the tumor were cleftlike and were of lower intensity than the remainder of the tumor on T1-weighted images and of higher intensity on heavily T2-weighted images. These parts corresponded to the areas of the tumor that were of lower density on dynamic bolus CT scans. Internal septa in the tumor of low intensity were also noted on all MR pulse sequences. These parts corresponded to low-density areas on delayed contrast-enhanced CT. Familiarity with the characteristics of the internal architecture of giant cavernous hemangiomas on MR imaging or dynamic bolus CT might be useful in making the correct diagnosis of this tumor.

Intraocular infusate with hemocoagulase for the control of bleeding during vitreous surgery

The effects of hemocoagulase in injectable form (hemocoagulating enzymatic fraction of South American snake Bothrops jararaca venom provided by Ravizza) on the control of intraocular bleeding during vitreous surgery were evaluated in rabbit eyes. Intraocular infusion solution with hemocoagulase (1 NIH thrombin unit/100 ml of BSS plus) significantly reduced the bleeding time. Electroretinogram b-wave and electroretinogram c-wave showed no abnormality. Infusate with hemocoagulase (1 NIH thrombin unit/100 ml of BSS plus) is not toxic to retinal tissue and appeared to be a useful agent for the control of intraocular bleeding during vitreous surgery.

Increased tumor control rates in murine fibrosarcoma by combined therapy with L-alanosine and radiation

L-Alanosine, an analog of L-aspartic acid, was investigated as one of a series of chemical compounds that may have inhibitory effects on the repair of potentially lethal damage caused by radiation using an in vivo murine fibrosarcoma (Meth-A tumor) in BALB/cBy male mice. The combined treatment of single administration of L-alanosine (600 mg/kg) and single dose of X-irradiation (20 Gy) on Meth-A tumors produced 62% tumor control, while the radiation alone resulted in less than 5% tumor control. The potentiating effect by L-alanosine was higher when the drug was administered 8 h prior to X-irradiation. The dose modification factor of the drug is estimated to be 1.4 for Meth-A tumor. The increased tumor control rates with combined alanosine and radiation were highly dependent upon the time and sequence of the combined treatment. The reason for reduced efficacy at treatment times of less than 8 h prior to X-irradiations appears to be related in part to the modulation of the body temperature by L-alanosine when combined with Ketamine, an anesthetic agent.

[Case report of the Sturge-Weber syndrome with intraoral finding]

The authors observed a 20-year-old female patient who had come to Department of Dentistry, Kyungpook National University Hospital due to the chief complaints of gingival enlargement and pain on the upper jaw. We performed the clinical, hematologic and radiologic examinations for the patient and obtained the following results; 1. We observed a nevus flammeus on the right side of the facial area, soft palate and buccal mucosa. 2. The enlargement of the upper and lower gingiva, we thought, was due to inflammatory reaction. 3. The above clinical signs were found in accordance with the maxillary and ophthalmic branch of trigeminal nerve. 4. The maxillary sinus was enlarged in Water's view. 5. Finally, we have reached the diagnosis of Sturge-Weber syndrome for the patient.

Reduction volume dependence of immunoreactive atrial natriuretic peptide secretion in isolated perfused rabbit atria

A new technique to permit gradual changes in atrial distension has been developed in an isolated perfused rabbit atrium preparation. Graded volume reduction in the atrium was induced by changing the elevation of the outflow catheter tip. Pressure reduction from 6 cm H2O atrial distension resulted in a decrease in atrial distension volume. Atrial distension by 6 cmH2O did not change the release of immunoreactive atrial natriuretic peptide (irANP). The graded reduction in atrial distension from 0.11 +/- 0.03 (1.5 cm H2O) to 1.36 +/- 0.19 microliters/mg wet weight (6.0 cm H2O) resulted in 1.7 (6.76 +/- 2.05 versus 3.83 +/- 1.18 pg/mg per min, n = 9, P less than 0.025) to 40.1-fold (77.66 +/- 17.82 versus 3.0 +/- 1.14 pg/mg per min, n = 11, P less than 0.025) increases in irANP release. IrANP release in response to the reduction of atrial distension was volume dependent. The relation of percentage increase in irANP release with the percentage reduction of atrial distension was exponential. The data suggest that the atrial muscle shortening, but not stretch per se, may be a potent direct stimulus for the regulation of irANP secretion.

Potentiation of radiation effects on multicellular tumor spheroids (MTS) of HeLa cells by lonidamine

Lonidamine is a potent inhibitor of spermatogenesis and a hyperthermic sensitizer. The previous study of lonidamine and radiation using two murine tumors demonstrated that tumor cure rates were significantly increased by radiation and concomitant lonidamine. In an effort to determine the radiobiologic factors involved with the potentiating effect of radiation by lonidamine, a series of cell culture studies were carried out using multicellular tumor spheroids (MTS) of HeLa Cells. When the MTS were treated with lonidamine in combination with fractionated irradiation, remarkable enhancement of growth inhibition was observed at the drug concentration of 10 micrograms/ml. On the other hand, there was no demonstrable enhancement of growth inhibition induced by a single dose of irradiation. Although the present findings would be consistent with the inhibitory action of potentially lethal damage repair of radiation by the drug, an alternative possibility is that the cells that have received the combined treatment have undergone a metabolic change, which has altered their sensitivity to the growth inhibitory effects of lonidamine. Based on the studies reported here and in mice, it is suggested that continued drug exposure over a prolonged period may provide an enhanced therapeutic effect, even in tumor varieties where the drug has no apparent antitumor activity on nonirradiated cells.

Biliary cystadenoma and cystadenocarcinoma: CT and sonographic findings

Eight women (ages 18-65 years; mean, 47 years) with biliary cystadenoma (n = 3) or cystadenocarcinoma (n = 5) were examined with computed tomography and sonography. The appearance of the tumors varied from unilocular cystic masses to multilocular cystic masses with multiple satellite tumors, although the majority (n = 6) of tumors were single, multilocular, and cystic. Cystic areas showed attenuation numbers under +30 HU. Papillary excrescences, nodular thickening of internal septa, and mural nodules, which showed contrast enhancement, were seen in one case of cystadenoma and all five cases of cystadenocarcinoma. One cystadenoma and one cystadenocarcinoma contained calcifications. Three cases showed connection to the intrahepatic bile ducts. Biliary cystadenoma and cystadenocarcinoma should be the primary diagnostic consideration when one detects in a middle-aged woman a well-encapsulated, multilocular cystic mass connected to the biliary system or prolapsing into the bile duct.

Three-dimensional reconstructions from incomplete data: interpretability of density maps at "atomic" resolution

Three dimensional data collection in electron microscopy is normally limited to a range of tilt angles that is less than +/- 90 degrees. Thus, even under the best conditions, experimental values of the structure factors will be missing within a solid cone in reciprocal space. Previous work has already shown that the missing cone of data can produce serious artifacts in three-dimensional density maps at modest resolution, for example approximately 15A. We now report, however, that a missing cone as large as +/- 30 degrees appears to have no serious effect on the three-dimensional density map of a protein at 3.6 A resolution, and we attribute this result to the fact that the electron density features are quite well separated from one another at that resolution. The map calculated with a +/- 30 degree missing cone is, furthermore, no more sensitive to noise (error) than is the full (isotropic) Fourier map. This result does not seem to be unreasonable in view of the fact that less than 14% of the data (i.e., signal) is lost due to the missing cone. Our numerical simulations therefore indicate that there should be no difficulty in interpreting high-resolution Fourier maps that can be produced with data that fall within realistic estimates of achievable resolution, tilt angles, and experimental error.

Phylogenetic study on the immunoreactive atrial natriuretic peptide in the heart

Using two antisera against atriopeptin III (AP III) which had different characteristics in cross-reactivities with atrial natriuretic peptide (ANP) analogs, we have measured an immunoreactive ANP (ir-ANP) in the heart extracts of several species. ir-ANP in atrial extracts showed both high and low molecular weights. Serial dilutions of atrial extracts from chickens, turtles, frogs, and fish yielded competition curves which were parallel to the standard curve of AP III with antiserum No. 4. In comparison with two serial dilution curves of atrial extracts made using two antisera, No. 4 and No. 9, we suggest that the amino acid at position 12 of ir-ANP in the atrial extracts of chicken, turtle, frog, and fish is not isoleucine but is some other amino acid.

Molecular model of the G protein alpha subunit based on the crystal structure of the HRAS protein

A structural model of guanine nucleotide-binding regulatory protein alpha subunits (G alpha subunits) is proposed based on the crystal structure of the catalytic domain of the human HRAS protein (p21ras). Because of low overall sequence similarity, structural and functional constraints were used to align the G alpha consensus sequence with that of p21ras. The resulting G alpha model specifies the spatial relationship among the guanine nucleotide-binding site, the binding site of the beta gamma subunit complex, likely regions of effector and receptor interaction, and sites of cholera and pertussis toxin modification. The locations in the model of the experimentally determined sites of proteolytic digestion, point mutation, monoclonal antibody binding, and toxin modification are consistent with and help explain the observed biological activity. Two important findings from our model are (i) the orientation of the G alpha model with respect to the membrane and (ii) the identification of the spatial proximity of the N- and C-terminal regions. Furthermore, by analogy to p21ras, the model assigns specific residues in G alpha required for binding the guanosine (G-box) and phosphates (PO4-box) and identifies residues potentially involved in the conformational switch mechanism (S-box). Specification of these critical regions in the G alpha model suggests guidelines for construction of mutants and chimeric proteins to experimentally test structural and functional hypotheses.

Synthesis of a more stable osmium ammine electron-dense DNA stain

Specific DNA staining for electron microscopic observation is simplified by a shorter synthesis of the staining reagent. The new, more reliable reagent, osmium ammine-B, is stable for more than a year, dissolves completely in water, and does not require reoptimization of staining conditions for every batch, yet reproducibly gives strong contrast to DNA-containing structures.

Effect of osmotic protection on nucleated cell killing by C5b-9: cell death is not affected by the prevention of cell swelling

Formation of C5b-9 channels in the plasma membrane can lead to erythrocyte lysis or nucleated cell death. Lysis of erythrocytes by complement occurs as a result of colloid osmotic swelling and rupture of the plasma membrane, due to the unregulated flux of ions and water through C5b-9 channels. This colloid osmotic mechanism of lysis is largely based on the evidence that the extent of hemolysis is reduced, when macromolecules are placed in the medium to balance the osmotic gradient created by intracellular macromolecules, which are too large to diffuse through complement channels. The role of colloid osmotic deregulation, as a cause of nucleated cell killing by C5b-9, however, has been recently questioned [Kim S., Carney D. F. and Shin M. L. J. Immun. 138, 1530 (1987)]. In the present study, we investigated the effect of osmotic protection, with an 81,000 mol. wt dextran or bovine serum albumin, on Ehrlich cell killing by complement channels. The results indicated that prevention of cell swelling by dextran did not reduce the extent or rate of nucleated cell killing by either small (C5b-9l), or large (C5b-9m), complement channels when assessed by vital dye stain. The release of cytoplasmic lactate dehydrogenase as an alternative measure of cell death, however, was retarded and/or reduced, in the presence of dextran or albumin, at concns that prevented cell swelling. These results indicate that C5b-9 can kill nucleated cells effectively, in the absence of colloidal osmotic cell swelling, and that release of cytoplasmic macromolecules may not be a reliable indicator of cell death, when osmotic protectants are employed.

Effects of allyl sulfide, germanium and NaCl on the development of glutathion S-transferase P-positive rat hepatic foci initiated by diethylnitrosamine

The modification potentials of allyl sulfide, germanium and NaCl on the development of preneoplastic hepatic enzyme altered foci were examined in an in vivo mid-term assay system. Rats were initially given a single dose (200 mg/kg), intraperitoneal injection of diethylnitrosamine (DEN) and, starting 2 weeks later, were treated with allyl sulfide, germanium and NaCl at a concentration of 0.5%, 0.05% and 5%, respectively, in the diet for 6 weeks and then killed. All rats were subjected to two-thirds partial hepatectomy at week 3. The modifying potential was scored by comparing the number and area per cm2 of induced glutathione S-transferase placental form-positive (GST-P+) foci in the liver with those of the corresponding control group given DEN alone. Allyl sulfide exerted an obvious inhibition of the development of GST-P+ foci as regards both number and area. On the contrary, germanium showed a significant increase in the number of GST-P+ foci, although the data for area were not altered. NaCl had no modifying effect on their development.

Structural differences between a ras oncogene protein and the normal protein

One of the most commonly found transforming ras oncogenes in human tumours has a valine codon replacing the glycine codon at position 12 of the normal c-Ha-ras gene. To understand the structural reasons behind cell transformation arising from this single amino acid substitution, we have determined the crystal structure of the GDP-bound form of the mutant protein, p21(Val-12), encoded by this oncogene. We report here the overall structure of p21(Val-12) at 2.2 A resolution and compare it with the structure of the normal c-Ha-ras protein. One of the major differences is that the loop of the transforming ras protein that binds the beta-phosphate of the guanine nucleotide is enlarged. Such a change in the 'catalytic site' conformation could explain the reduced GTPase activity of the mutant, which keeps the protein in the GTP bound 'signal on' state for a prolonged period time, ultimately causing cell transformation.

Inhibitory effect of capsaicin on mouse lung tumor development

The modification potentials of capsaicin on the development of pulmonary adenoma in newborn NIH (GP) mice were examined. Mice were given a single subcutaneous injection of 1 mg of benzo(a)pyrene (BP) or 40 micrograms of 9,10-demethyl-1,2-benzanthracene (DMBA) within 24 hours after birth and then 0.01% capsaicin (CAP) in the diet (Groups 1 and 2) for 6 weeks after weaning. Mice of groups 3, 4, 5 and 6 were given capsaicin, BP, DMBA and vehicle alone. All mice were sacrificed at week 9. Capsaicin caused a significant inhibitory effect on the frequency of tumor-bearing mice (BP-treated group) and the mean number of tumor (DMBA-treated group). The inhibitory activity is most profound in the group of female mice given DMBA combined with capsaicin. These results showed that capsaicin has inhibitory potential in the mouse lung tumor development induced by polycyclic aromatic hydrocarbons (BP and DMBA).

[Familial occurrence of intracerebral cavernous angioma]

This article reported a familial occurrence of intracerebral cavernous angioma in four members of one generation diagnosed by X-ray CT, MRI or operative specimen. Case 1, a 34-year-old female, was examined just after an episode of sudden convulsive seizure. On examination, she had a cutaneous angioma without any neurological deficit. X-ray CT revealed a high density mass lesion in the left frontal lobe, and MRI demonstrated a mass lesion in the chronic stage with an old hematoma circumscribed by hypointensity ring indicating peripheral hemosiderosis. Complete excision was carried out and a diagnosis of cavernous angioma was made after histological examination. Case 2, the 37-year-old brother of Case 1, suddenly developed left hemiparesis and hypesthesia with severe headache. X-ray CT revealed a high density mass in the right parietal lobe and two other calcifications. The right parietal lesion was excised and a histopathological diagnosis of cavernous angioma with intracerebral hematoma was made. Case 3, the 49-year-old sister of Case 1, suddenly fell into a coma and was admitted immediately. X-ray CT revealed a large pontine hemorrhage. She died on the 4th day of hospitalization without operative treatment. Necropsy was not carried out. Case 4, the 39-year-old sister of Case 1, was asymptomatic, however, she was examined on the supposition of a familial occurrence of intracerebral cavernous angioma. On examination, it was found she had multiple cavernous angioma without any neurological deficit. X-ray CT revealed parietal intracerebral calcification. MRI demonstrated a mass lesion with peripheral hypointensity ring in the right parietal lobe, and another small lesion in the pons.(ABSTRACT TRUNCATED AT 250 WORDS)

Presence of immunoreactive atrial natriuretic peptide in follicular fluid, ovary and ovarian perfusates

Immunoreactive atrial natriuretic peptide (ir-ANP) was measured in the follicular fluid of pig ovarian follicle, and rabbit ovarian homogenates and perfusates using a specific radioimmunoassay (RIA). Serial dilution curves made with the extracts of follicular fluid, ovarian homogenates and perfusates using SepPak C18 cartridges were parallel with the RIA standard curve. On gel filtration chromatography and reverse phase HPLC, all extracted materials showed high and low molecular weight forms of ir-ANP. The amount of ir-ANP in rabbit ovary was 40.70 +/- 0.39 pg/mg and that in follicular fluid of pig ovarian follicle was 18.88 +/- 2.49 pg/ml.

Plasma concentration of atrial natriuretic peptide in different phases of Korean hemorrhagic fever

Korean hemorrhagic fever (KHF) is an epidemic viral disease characterized by high fever, hemorrhagic tendency and renal failure, and by hemorrhages of right atrium and renal medulla as well as necrosis of anterior hypophysis. Plasma immunoreactive atrial natriuretic peptide (irANP) levels of 15 patients in the oliguric phase was 94.8 +/- 8.4 pg/ml (mean +/- SEM), 80% higher than of the normal control group (53.0 +/- 4.7 pg/ml; n = 28). In the diuretic phase it declined to 63.7 +/- 5.3 pg/ml (n = 26). Plasma renin activity (PRA) in the oliguric phase was 19.0 +/- 1.3 ng AI/ml/h, and in the diuretic phase 5.3 +/- 0.9 ng AI/ml/h, significantly higher than the control value (2.5 +/- 0.1 ng AI/ml/h). Elevations of irANP and PRA were not correlated in each group. Also systemic blood pressure as well as heart beats were significantly increased in the oliguric phase. These findings suggest that the increased irANP may have resulted from increased circulatory volume and that the ANP secretory process may not be affected by the disease.

A study of the bronchial provocation test with methacholine in patients with active pulmonary tuberculosis

Bronchial hyperreactivity is a characteristic feature of bronchial asthma. Recent respiratory infections, allergic rhinitis, atopic family history, pulmonary tuberculosis, pulmonary sarcoidosis, cystic fibrosis, and farmer's lung have also been demonstrated to have bronchial hyperreactivity to inhaled methacholine. It is not known if pulmonary tuberculosis can cause nonspecific bronchial hyperreactivity and what the mechanism would be. We therefore undertook to evaluate nonspecific bronchial hyperreactivity in active pulmonary tuberculosis using the bronchial provocation test with methacholine and we measured the total serum IgE and peripheral eosinophil count to seek some mechanisms. There were 5 patients among 18 subjects with active pulmonary tuberculosis whose response to methacholine was positive. The mean baseline FEV1 of positive responders was 71.40 +/- 17.39%, and that of negative responders was 110.18 +/- 17.65% (p less than 0.05). There were no significant differences in serum IgE and peripheral eosinophil count between positive and negative responders. We found that active pulmonary tuberculosis would increase the nonspecific bronchial response with methacholine, and the mechanism of the bronchial hyperreactivity in patients with active pulmonary tuberculosis may not be related to an immunologic mechanism but may be related to the stimulating receptors.

Retrograde colostomy and ileostomy enemas in neonates and infants: a simple combination of techniques

A combination of previously known techniques for retrograde opacification of ileostomies and colostomies has been used successfully in neonates and infants. This combination of techniques used on very small stomas allows easy retrograde opacification of bowel. The technique uses a small feeding tube, a larger Foley catheter with an inflatable balloon, and a Lucite compression device, the construction and use of which are discussed here.

Solitary angiokeratoma developed in one area of lymphangioma circumscriptum

We describe a boy who developed a dark brown colored nodule in an area of lymphangioma circumscriptum following repeated local injuries. The nodule showed the clinical and pathologic features of solitary angiokeratoma. It is possible that previous injuries predisposed the lesion to the development of solitary angiokeratoma.

Expression of the mouse metallothionein-I gene in Escherichia coli: increased tolerance to heavy metals

The cDNA of mouse metallothionein, a small metal-binding protein rich in cysteine, has been cloned downstream from a bacterial inducible promoter and expressed in Escherichia coli. Upon induction, E. coli harboring this cDNA clone contained a protein species readily labelled by [35S]cysteine in vivo and incorporated 10-times as much 109Cd from the medium than would otherwise be the case. We show that expression of metallothionein endows resistance in E. coli to heavy metal ions such as mercury, silver, copper, cadmium and zinc by sequestering rather than exclusion or conversion, common mechanisms of metal resistance in bacteria.

Interaction of hyperthermia and pentamidine in HeLa S-3 cells

Pentamidine is similar to rhodamine-123 in chemical structure and state of electron charge, and rhodamine-123 was previously shown to be a hyperthermic sensitizer under appropriate cell culture conditions. The present experiments were carried out to determine whether pentamidine would potentiate hyperthermic cell killing and, if so, under what cultural conditions. Exposure of HeLa cells to pentamidine (80 microM) up to 4 h was not cytotoxic in culture medium in the presence or absence of glucose at 37 degrees C and pH 7.4. Cells in the glucose-deprived medium became progressively sensitive to killing as temperature and drug concentration were increased. On the other hand, there was a moderate level of enhanced cell killing in the glucose-fed medium at 42 degrees C. The enhanced effects of heat by the drug were most pronounced under alkaline pH of the culture medium. The cell kill under acidic pH was far less than that observed at neutral or alkaline pH; these effects may be a result of decreased cellular uptake of pentamidine. Together with our previous results on rhodamine-123 and glycolytic inhibitors, the present data with pentamidine are consistent with the concept that deprivation of cellular energy increases sensitivity to cell killing by heat.

Selective killing of glucose-deprived hypoxic cells by hyperthermia. I. Protection by purine ribonucleosides

Energy deprivation increases sensitivity to killing by hyperthermia. Hypoxic cells become dramatically sensitive to heat under glycolytic inhibition or glucose deprivation. To define the role of glucose metabolism in hypoxic cells in the presence or absence of elevated temperatures, cell culture studies were carried out to determine whether the enhanced cell killing of glucose-deprived hypoxic cells could be reversed by nucleoside supplementation. The results with HeLa cells showed that purine ribonucleosides were capable of reversing the enhanced heat-induced cytotoxicity under appropriate cultural conditions. Pyrimidine ribonucleosides and deoxyribonucleosides were ineffective. Based on the known metabolism of purine ribonucleosides, it is postulated that protection from hyperthermic killing by purine nucleosides comes about as a result of increased energy production via the purine nucleotide cycle.