[Experimental chemotherapy of human gastric cancer cell lines in vitro and in nude mice]

Cytotoxic effects of allyl trisulfide (Alt, a synthetic chemical identical with one of the main active principles of garlic), 5 FU, MMC and DDP on SGC 7901 ( a moderately differentiated human gastric adenocarcinoma cell line) and MGC 803 (a poorly differentiated human gastric mucoadenocarcinoma cell line) had been reported before. In this paper, effects of repeated two doses of each drug and the combination of two drugs on these two cell lines were studied using relative clone-survival test. The inhibitory effects of Alt, MMC alone or combined on MGC tumor in nude mice were observed. No drug resistance was found when any one of the four agents at the same concentration were repeated twice separately at 60 hour interval in vitro. The cytotoxic effect of the repeated two doses was approximately equal to that of the single dose at double concentration. The in vitro test of combinations of two drugs showed that Alt plus MMC or 5 FU plus DDP had markedly synergistic effect on MGC cells; 5 FU plus DDP had markedly synergistic effect on SGC cells. The inhibition test on the growth of MGC tumor in nude mice indicated that the inhibition rates of Alt, MMC alone or combined were 58.3%, 86.3% and 84.3%. The systemic toxic effect of MMC alone was severe, whereas Alt alone or MMC plus Alt showed mild toxicity. For this reason, Alt plus MMC is recommended for clinical trials on poorly differentiated gastric cancer. In addition, for the comparison of in vitro test dose and clinical dose of each drug, the principle of clinical adult dose range (CADR) is proposed.

On the Efficiency of NC Tool Path Planning for Face Milling Operations

Face milling operations are important for producing flat machined surfaces. Existing methodologies to generate NC tool path for face milling are employed everyday by manufacturing industries without considering the impact of tool path selection. A systematic study has been conducted in order to identify those critical control parameters affecting length of cut in face milling operations. Basic polygons, from triangles to heptagons, were planned using both window frame and stair case milling procedures. For each polygon, each vertex was introduced as a possible starting point for a single run in the window frame milling. The cutting orientation was further examined for stair case milling by enumerating the tool sweep angle from 0 to 180 (and 180 to 0 as well) degrees from each vertex. The results are analyzed and important conclusions are drawn noting the efficiency of the cutting process.

Tissue-specific expression of the human alpha 1-antitrypsin gene is controlled by multiple cis-regulatory elements

Human alpha 1-antitrypsin (AAT) is expressed in the liver, and a 318 bp fragment immediately flanking the CAP site of the gene was found to be sufficient to drive the expression of a reporter gene (CAT) specifically in hepatoma cells. The enhancing activity however, was orientation-dependent. The DNA fragment was separated into a distal region and a proximal region. A "core enhancer" sequence GTGGTTTC is present within the distal region and is capable of activity enhancement in both orientations when complemented by the proximal region in the sense orientation. The results strongly suggest that there are multiple cis-acting elements in the human AAT gene that confer cell specificity for its expression. Nuclear proteins prepared from the hepatoma cells bound specifically to the proximal region in a band-shifting assay that was resistant to competition by the globin promoter DNA. Foot-printing analysis showed a protected domain within the proximal region that contains a nearly perfect palindromic sequence TGGTTAATATTCACCA, which may be important in the regulation of AAT expression in the liver.

Continuous-wave operation of extremely low-threshold GaAs/AlGaAs broad-area injection lasers on (100) Si substrates at room temperature

Room-temperature continuous-wave operation of large-area (120 microm x 980 microm) GaAs/AlGaAs graded-refractive-index separate-confinement heterostructure lasers on (100) Si substrates has been obtained. Minimum threshold-current densities of 214 A/cm(2) (1900-microm cavity length), maximum slope efficiencies of about 0.8 W/A (600-microm cavity length), and optical power in excess of 270 mW/facet 900-microm cavity length) have been observed under pulsed conditions.

Oral cholecystography and sonography of gallbladder in cholecystectomy patients

In comparing the diagnostic specificity and sensitivity of oral cholecystography with that of sonography in 479 patients in a community hospital, the oral cholecystogram, when used with a double dose of contrast agent, showed greater specificity (1.00) and sensitivity (0.99) than the sonogram (0.54 and 0.94, respectively). Because of lower cost, the oral cholecystogram should be used as the initial diagnostic study when cholelithiasis is suspected, unless specific contraindications exist.

Interactions between a DNA-binding transcription factor (COUP) and a non-DNA binding factor (S300-II)

We have identified previously two transcription factors, COUP (chicken ovalbumin upstream promoter) and S300-II, from HeLa cell nuclear extracts. In this paper, the purine base and the phosphate backbone contact sites for the COUP transcription factor were defined. These studies indicate that the COUP box transcription factor interacts with specific base residues in the major groove of the DNA helix. In addition, we have purified the S300-II factor over 100,000-fold. The polypeptide possessing functional transcriptional activity has been identified by SDS-PAGE followed by gel-slice elution and a renaturation assay. It is absolutely required for in vitro function of the ovalbumin promoter. In addition, S300-II stimulates transcription from the MMTV and lysozyme promoters. Kinetic studies probing the interaction of S300-II with COUP factor suggest that it may stabilize COUP-promoter complexes by slowing their rate of dissociation.

Pediatric patients with achondroplasia: CT evaluation of the craniocervical junction

Twenty-six patients (4 months to 6 years old) with achondroplasia complicated by sleep apnea and/or other neurologic manifestations underwent plain computed tomography (CT) of the craniocervical junction; six also underwent CT myelography. For objectification, multiplanar reconstruction was used to complement axial plane measurements by providing coronal and sagittal measurements; multiplanar reconstruction also improved perception of the longitudinal relationships between the brain stem and subarachnoid space. A narrow subarachnoid space was found in all 26 patients; marked cord compression was present in nine, six of whom underwent CT myelography. These six had marked focal obliteration of the subarachnoid space on both plain CT and CT myelography. Since the subarachnoid space immediately above and below the craniocervical junction is normally capacious, when marked constriction was present, no additional information could have been gained from CT myelography. Thus, plain CT was shown to be sufficient for surgical planning (suboccipital decompression) in nine patients with cord compression due to achondroplasia.

Localization and immunological characterization of antigenic domains of the rabies virus internal N and NS proteins

To locate epitopes on internal antigens of rabies virus, purified N and NS proteins of the nucleocapsid were cleaved at methionine, tryptophan or glutamic acid residues, transferred to nitrocellulose and immunostained using monoclonal antibodies (MAbs) specific for N and NS proteins, respectively. Five MAb-positive fragments of N protein and one fragment of NS protein were located after NH2-terminal amino acid sequence analysis within the deduced amino acid sequences of N and NS proteins. Antigenic analysis of synthetic overlapping peptides corresponding to the amino acid sequences of these fragments localized two major antigenic sites of N protein and one antigenic site of NS protein. Like the N- and NS-specific MAbs, anti-peptide antisera produced against the different synthetic antigens either reacted in a type-common fashion with all rabies virus strains, or in a type-specific manner with a restricted number of strains. The synthetic peptides corresponding to the three antigenic regions of the N and NS proteins also stimulated proliferation of human T lymphocytes derived from vaccinees who received inactivated rabies virus vaccine. This suggested that the antigenic regions of N and NS proteins are recognized by both B and T cells.

Use of oxidizing dyes in combination with 2-cyanocinnamic acid to enhance hyperthermic cytotoxicity in L929 cells

Two widely used oxidizing dyes, 2,3,5-triphenyltetrazolium chloride and methylene blue, can greatly potentiate hyperthermic cytotoxicity when administered simultaneously with 2-cyanocinnamic acid. The same compounds are virtually nontoxic to L929 cells if administered alone at 42 degrees C or in combination with 2-cyanocinnamic acid at 37 degrees C. Cytotoxicity was synergistically enhanced by the combined regimens after 3 h of heat exposure. Quercetin, a bioflavonoid known to enhance hyperthermic cytotoxicity, also acts synergistically when administered in combination with 2-cyanocinnamic acid and this effect is apparent after 1 h of heat exposure. Since these compounds do not greatly interfere with pyruvate metabolism at either normal or heat shock temperatures, a mechanism of action based on depletion of NAD(P)H is considered.

CT myelography and MR imaging of acute transverse myelitis

Two patients with acute transverse myelitis were evaluated by both CT myelography and magnetic resonance. Computed tomographic myelography showed fusiform cord enlargement involving several levels; one patient had a subtotal block in the thoracic spine. Magnetic resonance displayed similar findings of cord enlargement. The demonstration of cord swelling in acute transverse myelitis is an uncommon radiologic manifestation of the disease.

DNA fragments of Bombyx mori nuclear polyhedrosis virus containing the promoters active in prokaryotes

Using a promoter probe plasmid in E. coli called pHE5, eight different HindIII and one SalI DNA fragments of Bombyx mori nuclear polyhedrosis virus, directing the expression of the tetracycline resistance gene, have been cloned and isolated. The tetracycline resistance levels of the strains containing the recombinant plasmids were measured. Among them, the highest level of the resistance to tetracycline was 30 micrograms/ml. Part of the nucleotide sequence of a DNA fragment was determined. A sequence similar to the E. coli promoter was found.

Cervicomedullary compression in young patients with achondroplasia: value of comprehensive neurologic and respiratory evaluation

We studied prospectively 26 young patients with achondroplasia to test two hypotheses: that respiratory problems may be the result of occult spinal cord compression, and that achondroplastic patients with cord compression might have occult respiratory abnormalities. Respiratory abnormalities were present in 85%, the majority caused by a primary problem of the pulmonary system, such as small thoracic cage or obstructed airway. Three patients had hypoxemia, recurrent cyanotic spells, and episodes of respiratory distress explainable only by cervicomedullary cord compression; in each patient, respiratory problems were alleviated by decompressive surgery. Another six patients with cervicomedullary compression had, in addition, at least one primary pulmonary cause of respiratory problems. After decompressive surgery the respiratory problems improved in three and were unchanged in three. Reconstructed sagittal CT images proved the most sensitive technique for detecting craniocervical stenosis as a cause of cervicomedullary cord compression, although some degree of stenosis was present in nearly all of the patients.

Preliminary studies on antigenic variation of poliovirus using neutralizing monoclonal antibodies

Cross-neutralization assays were done using 85 strains of poliovirus type 1 with five groups of monoclonal antibodies. These strains were classified into 10 subgroups which had marked differences in antigenicity. Subgroups P1-2 (28%) and P1-5 (43%) were dominant and have been epidemic in China in recent years. These two subgroups were antigenically different from the Sabin-1 strain, but according to their responses to one group of monoclonal antibodies they had antigenic epitopes in common with the Mahoney and Brunhilde strains. Similarly, 91 strains of type 3 poliovirus were classified into six subgroups with another five groups of monoclonal antibodies. The results showed that strain P3/Yunnan/2/84, which was isolated from cases of poliomyelitis in a local epidemic in the Yunnan province of China in 1984, and strain P3/Finland/23127/84, which was isolated in Finland in 1984, were both antigenically different from the Sabin-3 strain and the reference virulent strain.

Pulmonary function changes in cirrhosis of the liver

Pulmonary function tests were performed in 21 cirrhotic patients with ascites, and these were compared with 50 normal controls. The vital capacity in the cirrhotic group was 93.67 +/- 12.5% and in controls was 102.47 +/- 15.22%, p less than 0.05. The maximum voluntary ventilation in cirrhotic patients was 89.33 +/- 25.4% and in controls was 127.48 +/- 28.44%, p less than 0.001. The functional residual capacity in cirrhotic patients was 2362.19 +/- 845.08 ml and in controls was 3085.1 +/- 837.92 ml, p less than 0.01. The total lung capacity in cirrhotic patients was 4675 +/- 1204.09 and in controls was 5791.56 +/- 1033.99, p less than 0.01. The first forced expiratory volume in cirrhotic patients was 70.1 +/- 12.79%, whereas that in controls was 77.74 +/- 9.18%, p less than 0.05. These results imply that in cirrhosis of the liver there are prominent restrictive ventilatory disorders as well as obstructive disorders.

Effect of cooling of the culmen of the cerebellar vermis on chemically induced stepping in guinea pigs

A regular 'stepping automatism' was induced via our recently reported SIS (substances capable of inducing stepping) in guinea pigs. Reversible cooling (5-0 degrees C) or partial ablation of the culmen of the cerebellar vermis could facilitate SIS-induced stepping, whereas electrical stimulation (300 microA up) of the same region could attenuate or abolish stepping. Cooling could only facilitate, but not trigger stepping movements. The above-mentioned facilitation was most prominent in those guinea pigs that exhibited a weak stepping automatism. Cooling of the lateral part of the culmen of the cerebellar vermis and hemisphere mainly facilitated stepping of the ipsilateral forelimb. When the interfacial temperature between the cooling probe and tentorium cerebelli was appropriate (5-0 degrees C), cooling could mimic the effects of ablation to a great extent.

Blood pressure response of two types of Goldblatt hypertensive rats to enalapril

Enalapril (MK-421), a new angiotensin converting enzyme inhibitor, reduces the blood pressure in one-kidney, one-clip hypertensive rats at 30 mg/kg p.o. (n = 12). On the fifth day and during the fifth week after renal artery constriction, systolic blood pressure decreased from 196 +/- 4 and 240 +/- 5 mm Hg pretreatment to 159 +/- 8 and 225 +/- 3 mm Hg, respectively (p less than 0.001 and 0.05, respectively) and was maintained at this level for about 8 h. Serum angiotensin converting enzyme activity was significantly inhibited by enalapril. Similarly, enalapril (30 mg/kg p.o.) in two-kidney, one-clip hypertensive rats (n = 18) on the fifth day and during the fifth week after operation resulted in a decrease in blood pressure from 162 +/- 5 and 217 +/- 5 mm Hg to 117 +/- 6 and 120 +/- 7 mm Hg, respectively, to the preoperative normotensive level (113 +/- 1 mm Hg). These results indicate that the renin-angiotensin system may play an important role in the pathogenesis of two-kidney, one-clip hypertensive rats. However, in the pathogenesis of one-kidney, one-clip hypertensive rats, other mechanisms seem to be involved besides the renin-angiotensin system.

Predicting antibody hypervariable loop conformations. II: Minimization and molecular dynamics studies of MCPC603 from many randomly generated loop conformations

We describe a method for predicting the conformations of loops in proteins and its application to four of the complementarity determining regions [CDRs] in the crystallographically determined structure of MCPC603. The method is based on the generation of a large number of randomly generated conformations for the backbone of the loop being studied, followed by either minimization or molecular dynamics followed by minimization starting from these random structures. The details of the algorithm for the generation of the loops are presented in the first paper in this series (Shenkin et al. [submitted]). The results of minimization and molecular dynamics applied to these loops is presented here. For the two shortest CDRs studied (H1 and L2, which are five and seven amino acids long), minimizations and dynamics simulations which ignore interactions of the loop amino acids beyond the carbon beta replicate the conformation of the crystal structure closely. This suggests that these loops fold independently of sequence variation. For the third CDR (L3, which is nine amino acids), those portions of the CDR near its base which are hydrogen bonded to framework are well replicated by our procedures, but the top of the loop shows significant conformational variability. This variability persists when side chain interactions for the MCPC603 sequence are included. For a fourth CDR (H3, which is 11 amino acids long), new low-energy backbone conformations are found; however, only those which are close to the crystal are compatible with the sequence when side chain interactions are taken into account. Results from minimization and dynamics on single CDRs with all other CDRs removed are presented. These allow us to explore the extent to which individual CDR conformations are determined by interactions with framework only.

Identification of two factors required for transcription of the ovalbumin gene

Two transcription factors, COUP and S300-II, were isolated and partially purified from HeLa cell nuclear extracts. Both factors are required for the efficient transcription in vitro of the ovalbumin gene but not the simian virus 40 early genes. COUP factor binds to the chicken ovalbumin upstream promoter (COUP) sequence which lies between -70 to -90 base pairs upstream from the cap site. A series of competition experiments with a band-shifting assay was carried out to determine the relative affinity of COUP box transcription factor for various promoters. We found that a promoter DNA fragment isolated from the ovalbumin gene competes better than those isolated from the ovomucoid, Y, and alpha-genes. In contrast, the the simian virus 40 early genes, the beta-globin gene, and the adenosine deaminase gene promoters do not compete well in this assay. The molecular weight of the COUP factor was estimated by S-300 column chromatography, glycerol gradient centrifugation to be 90,000. However, two bands were observed in sodium dodecyl sulfate gel electrophoresis of cross-linked COUP factor to a 32P-labeled oligonucleotide containing the COUP sequence. The protein moieties of the major and minor bands were estimated to be 85,000 to 90,000 and 40,000 to 45,000, respectively. The S300-II factor with an apparent molecular weight of 45,000 in an S-300 column is required for function in an in vitro reconstituted transcription system. In contrast to the COUP factor, the S300-II factor does not have apparent specificity for binding to the ovalbumin gene promoter. The S300-II factor may function by interacting with RNA polymerase or other DNA-binding transcription factors.