Cytotoxic polyprenylated xanthones from the resin of Garcinia hanburyi

Twelve new xanthones (1-12), a pair of new natural products (13 and 14), and 18 known related compounds were isolated from the resin of Garcinia hanburyi. The structures of 1-14 were elucidated by detailed spectroscopic analyses. A cytotoxic assay of the isolated compounds revealed that, with the exception of 2, these compounds were active against the HeLa tumor cell line.

NMR spectral assignments of isoprenylated flavanones from Sophora tonkinensis

The phytochemical investigation of extracts from the roots of Sophora tonkinensis yielded three new isoprenylated flavanones, the tonkinochromanes F (2), G (3), and H (5), along with four known compounds. Structural elucidation of the compounds were established on the basis of spectral data, particularly by the use of 1D NMR and several 2D shift-correlated NMR pulse sequences ((1)H-(1)H COSY, HSQC, HMBC, and ROESY).

[Expression and significance of CD44(+)ESA(+)CD24(-/low), stem cell markers for breast cancer, in non-small-cell lung carcinoma]

BACKGROUND & OBJECTIVE

Stem cells are found in all human tissues, while tumor stem cells (TSCs) are also detected in tumors. TSC of breast cancer has been separated and its markers have been affirmed. However, TSC of lung carcinoma has not been separated yet. This study was to investigate the expression and significance of stem cell markers for breast cancer (CD44(+)ESA(+)CD24(-/low)) in non-small-cell lung carcinoma (NSCLC).

METHODS

Expressions of CD44,ESA and CD24 of tumor tissues in 77 cases of NSCLC patients were detected using immunohistochemistry. The correlations of the expression of the makers to tumor size, smoking, histological type, differentiation, lymphoid metastasis, and prognosis were analyzed.

RESULTS

The expressive rates of CD44,ESA and CD24 were 63.6%, 66.2% and 7.8%, respectively in 77 NSCLC tissues. CD44-positive expression was significantly higher in poorly differentiated and undifferentiated group than in well differentiated group. ESA-positive expression was significantly higher in well differentiated group than in poorly differentiated and undifferentiated group. The ESA positivity was significantly higher in glandular carcinoma than in squamous carcinoma. The expressive rate of CD44(+)ESA(+)CD24(-/low) in 77 cases of NSCLC was 36.4%. No correlations were found in the expression of CD44(+)ESA(+)CD24(-/low) to smoking, tumor size, histological type, differentiation, lymphoid metastasis and prognosis (P>0.05).

CONCLUSION

Expressions of stem cell markers for breast cancer (CD44(+)ESA(+)CD24(-/low)) are not associated with tumor size, histological type, differentiation, lymphoid metastasis and prognosis of NSCLC.

Cytotoxic diterpenoids from Euphorbia helioscopia

Four new jatrophane-type diterpenoids (1-4), together with 16 known related compounds, were isolated from the Chinese medicinal plant Euphorbia helioscopia. The structures of 1-4 were determined on the basis of spectroscopic and chemical methods. Cytotoxicity of the isolated compounds against HeLa and MDA-MB-231 cells was evaluated, with only helioscopinolide A (5) and euphornin (3a) being active.

Structure elucidation and NMR spectral assignments of three new lignan glycosides from Akebia trifoliata

Three new lignan glycosides (1-3) were isolated from the stems of Akebia trifoliata. Their structures were elucidated as (7R,8R,7'R,8'R)3,3',5,5'tetramethoxy-4,4'dihydroxy-7,9':7',9-diepoxylignan-4-O-beta-D-glucopyranoside (1), (7S,8S,8'R)-4,4',9-trihydroxy-3,3',5,5'-tetramethoxy-7,9'-epoxylignan-7'-one 9-O-beta-D-glucopyranoside (2), (7R,8R,8'S)-4,4',9-trihydroxy3,3',5,5'-tetramethoxy-7,9'-epoxylignan-7'-one 9-O-beta-D-glucopyranoside (3) by spectral analyses, primarily NMR, MS and CD. The NMR assignments for the compounds were carried out using 1H, 13C, DEPT, COSY, HSQC, HMBC and ROESY NMR experiments.

Ingenane diterpenoids from Euphorbia esula

An extensive study of metabolites present in Euphorbia esula led to isolation of 16 ingenane diterpenoids 1-16 together with the known ingenane derivative 17 and four known cycloartane triterpenoids. Their structures were elucidated on the basis of spectroscopic studies and comparison with known related compounds. All the compounds were assayed for their inhibitory activity against human HeLa cervical cancer cell line.

Terpenoids and bisbibenzyls from Chinese liverworts Conocephalum conicum and Dumortiera hirsuta

Four new monoterpene esters, 2alpha,5beta-dihydroxybornane-2-cinnamate (1), 2alpha,5beta-dihydroxybornane-5-acetyl-2-cinnamate (2), 2alpha,5beta-dihydroxybornane-2-p-hydroxycinnamate (3) and 2alpha,5beta-dihydroxy-bornane-2-cis-p-hydroxycinnamate (4), together with a known compound 3,4-dimethoxystyrene (5) were isolated from Chinese liverwort Conocephalum conicum and six known compounds, 5,7-dihydroxycalamenene (6), 7-hydroxycalamenene (7), lunularin (8), riccardin C (9), marchantin C (10) and riccardin D (11) were isolated from Dumortiera hirsuta. Their structures were elucidated by extensive spectral analysis and chemical correlations. Compounds 1 and 8 showed moderate cytotoxicity against human HepG2 cells with IC50 4.5 microg/ml and 7.4 microg/ml, respectively, while compound 8 also showed antimicrobacterial activity against Pseudomonas aeruginosa with minimum inhibitory concentration at 64 microg/ml.

[Expression and clinical significance of vascular endothelial growth factor C and vascular endothelial growth factor receptor 3 in non-small cell lung carcinoma]

BACKGROUND & OBJECTIVE

Vascular endothelial growth factor C (VEGF-C) and vascular endothelial growth factor receptor 3 (VEGFR-3) play important roles in lymphangiogenesis of malignant tumors; their expression are closely related to lymphatic metastasis of malignant tumors. This study was designed to investigate the expression and clinical significance of VEGF-C and VEGFR-3 in non-small cell lung cancer (NSCLC).

METHODS

The expression of VEGF-C and VEGFR-3 in 77 specimens of NSCLC were detected by immunohistochemistry; their correlations to lymphatic vessel density (LVD), tumor size, histological type, differentiation, lymphatic metastasis, clinical recurrence, and survival time of the patients were analyzed.

RESULTS

Positive rate of VEGF-C was 58% in NSCLC, and that of VEGFR-3 was 42%. The expression of VEGF-C protein was negatively correlated with the differentiation of NSCLC (r=-0.32, P=0.018). The expression of VEGF-C and VEGFR-3 were related to lymphatic metastasis, LVD, tumor size, and survival time of the patients. The expression of VEGF-C was positively related with that of VEGFR-3 (r=0.23, P=0.045).

CONCLUSION

The expression of VEGF-C and VEGFR-3 are closely related with lymphatic metastasis and prognosis of NSCLC; their high expression indicate high risk of lymphatic metastasis and poor prognosis.

Multivariate analysis of the risk for pulmonary complication after gastrointestinal surgery

AIM: To identify the risk factors for postoperative pulmonary complications (PPC) after gastrointestinal surgery.

METHODS: A total of 1002 patients undergoing gastrointestinal surgery in the Second Affiliated Hospital, Sun Yat-Sen University, during December 1999 and December 2003, were retrospectively studied.

RESULTS: The overall incidence of PPC was 22.8% (228/1002). Multivariate logistic analysis identified nine risk factors associated with PPC, including age odds ratio (OR = 1.040) history of respiratory diseases (OR = 2.976), serum albumin (OR = 0.954), chemotherapy 2 wk before operation (OR = 3.214), volume of preoperative erythrocyte transfusion (OR = 1.002), length of preoperative antibiotic therapy (OR = 1.072), intraoperative intratracheal intubation (OR = 1.002), nasogastric intubation (OR = 1.050) and postoperative mechanical ventilation (OR = 1.878). Logistic regression equation for predicting the risk of PPC was P(1) = 1/[1+e^{-(-3.488+ 0.039×Y+1.090×Rd+0.001×Rbc-0.047×Alb+0.002×Lii+ 0.049×Lni+0.630×Lmv+0.070×Dat+ 1.168×Ct)}].

CONCLUSION: Old patients are easier to develop PPC.

[Effect of cyclooxygenase-2,and matrix metalloproteinase-2 expression on prognosis of lung cancer]

BACKGROUND & OBJECTIVE

Expression of cyclooxygenase-2 (COX-2)and matrix metalloproteinase-2 (MMP-2)increased in most tumor tissues. Inhibitors of both COX-2 and MMP-2 have been experimentally and clinically proved effective against the development of tumor. Our study was designed to investigate the expression of COX-2 and MMP-2, and the effect of those proteins on lymphoid metastasis and prognosis of lung cancer.

METHODS

SP immunohistochemistry was used to determine the expression of COX-2 and MMP-2 in 42 patients with lung cancer. Kaplan-Meier and log-rank test were used to compare the survival time of positive staining group and negative staining group.

RESULTS

The positive rate of COX-2 was 31%, and that of MMP-2 was 62%. The survival time in positive COX-2 group was significantly shorter than that in negative COX-2 group (P=0.019). The lymphoid metastasis rate of positive MMP-2 group was significantly higher than that of negative MMP-2 group (P=0.009). The survival time in positive MMP-2 group was significantly shorter than that in negative MMP-2 group (P=0.001). No relationship was found between the expression of COX-2 and MMP-2 (P=0.257).

CONCLUSION

The expression of COX-2 and MMP-2 are closely correlate with the prognosis of lung cancer, and the over-expression of those proteins suggest poor prognosis in patients with lung cancer.

Negative regulation of prophenoloxidase (proPO) activation by a clip-domain serine proteinase homolog (SPH) from endoparasitoid venom

Most parasitic wasps inject maternal factors into the host hemocoel to suppress the host immune system and ensure successful development of their progeny. Melanization is one of the insect defence mechanisms against intruding pathogens or parasites. We previously isolated from the venom of Cotesia rubecula a 50 kDa protein that blocked melanization in the hemolymph of its host, Pieris rapae [Insect Biochem. Mol. Biol. 33 (2003) 1017]. This protein, designated Vn50, is a serine proteinase homolog (SPH) containing an amino-terminal clip domain. In this work, we demonstrated that recombinant Vn50 bound P. rapae hemolymph components that were recognized by antisera to Tenebrio molitor prophenoloxidase (proPO) and Manduca sexta proPO-activating proteinase (PAP). Vn50 is stable in the host hemolymph-it remained intact for at least 72 h after parasitization. Using M. sexta as a model system, we found that Vn50 efficiently down-regulated proPO activation mediated by M. sexta PAP-1, SPH-1, and SPH-2. Vn50 did not inhibit active phenoloxidase (PO) or PAP-1, but it significantly reduced the proteolysis of proPO. If recombinant Vn50 binds P. rapae proPO and PAP (as suggested by the antibody reactions), it is likely that the molecular interactions among M. sexta proPO, PAP-1, and SPHs were impaired by this venom protein. A similar strategy might be employed by C. rubecula to negatively impact the proPO activation reaction in its natural host.

Beta-1,3-glucan recognition protein-2 (betaGRP-2)from Manduca sexta; an acute-phase protein that binds beta-1,3-glucan and lipoteichoic acid to aggregate fungi and bacteria and stimulate prophenoloxidase activation

We have isolated and characterized a new beta-1,3-glucan recognition protein that is present in Manduca sexta cuticle and hemolymph. This 52 kDa protein, designated betaGRP-2, is 57% identical in sequence to betaGRP-1 from larval hymolymph of the same insect. BetaGRP-2 differs from betaGRP-1 in its absence of the naive larvae before the wandering stage begins. Transcription of the betaGRP-2 was up-regulated in larvae challenged with yeast or bacteria. BetaGRP-2 contains a region with sequence similarity to several glucanases but lacks glucanase activity. It aggregates yeasts and bacteria to, perhaps, limit the spread of invading cells and ensure a localized defense reaction. BetaGRP-2 binds laminarin and lipoteichoic acid, but not lipopolysaccharide. Laminarin-triggered prophenoloxidase activation was greatly enhanced in the induced larval hemolymph supplemented with purified betaGRP-2. Complementing other studies on pattern recognition molecules in M. sexta, these results indicate that a complex system of protein sensors is an integral component of the insect immune system and that different recognition molecules have overlapping binding specificity and functions.

The prediction of the structural class of protein: application of the measure of diversity

Based on the concept that the structural class of a protein is mainly determined by its secondary structure sequence, a new algorithm for prediction of the structural class of a protein is proposed. By use of the number of alpha -helices, beta -strands, and betaalphabeta fragments, the structural class of a protein can be predicted by an algorithm based on the increment of diversity (ID), in which the sole prediction parameter-the increment of diversity is used as the index of prediction of structural class of a protein. The results indicate that the high rates of correct prediction are obtained for complete set (standard set) from Brookhaven Protein Data Bank-CD ROM (PDB) published in October 1995 and the test set newly released from Brookhaven Protein Data Bank-CD ROM (PDB) before July 1998, respectively.

Acoustical diffraction tomography in a finite form and its computer simulations

Until now, all acoustical diffraction reconstruction algorithms are in infinite forms. All of these algorithms have disadvantages: severe limitations on scatterers or tedious calculations. In this paper, we present a new reconstruction algorithm in a finite form using the method of formal parameter, which is very simple. This new algorithm gives an exact reconstruction when the amplitude of the scattered wave is smaller than that of the incident wave everywhere. This assumption is much less restrictive than that for the first- and second-order Born approximations. Although this new algorithm is in a finite form, it is still an approximate one when the amplitude of the scattered wave is not smaller than that of the incident wave everywhere. However, it still gives a good reconstruction when the amplitude of the scattered wave is a little greater than that of the incident wave in some area. Some numerical examples have confirmed these conclusions.

Diterpenoids from Isodon lophanthoides

A new diterpenoid was isolated from the leaves of Isodon lophanthoides, together with two known diterpenoids, lophanic acid and 8(17),12,14-labdatriene-19-oic acid. The structure of the new compound was determined to be 11 beta-hydroxyisopimara-8,15-diene-3-one (1) on the basis of spectroscopic evidence.

ent-kaurane diterpenoids from Isodon lungshengensis

Six new ent-kaurane diterpenoids, lungshengenins B-G (1-6), together with three known diterpenoids, lungshengenin A (7), inflexin (8), and lushanrubescinsin C (9), were isolated from the leaves and tender branches of Isodon lungshengensis. Their structures were elucidated by means of spectroscopy, mainly 1D and 2D NMR techniques. Lungshengenins A (7), C (2), and G (6) were cytotoxic toward K562 cells, having IC(50) values equal to or less than 10 microg/mL.

[Controlled observation on naoxuenin in treating 22 hypertensive encephalorrhagia patients]

42 cases of hypertensive encephalorrhagia (HER) were randomly divided into two groups. All cases received treatment within three days after the attack, group I received current conventional treatment as control, group II took 100ml Naoxuenin (NXN) oral liquid with conventional treatment. Effects were evaluated after 14-day treatment. Results indicated that NXN had direct therapeutic effect or/and synergistic effect on HER in acute phase, the mortality was significantly lowered (P < 0.05) and the recovery of nerve function speeded up in group II. And NXN displayed similar effect on different Syndromes and Types of the acute phase of HER (P > 0.05). Analysis of results of hemorheological examination of pre- and post-treatment suggested that NXN could improve the microcirculation and prevent the high hemo-viscosity syndrome caused by dehydration therapy.

[Antidotal effects of 2,3-dimercaptopropane-1-sulfonate sodium (DMPS) and combined with diazepam on acute poisoning caused by sodium ammonium dimethyl-2-propano-1,3-dithiosulfate monohydrate (SCD)]

In mice, DMPS (250 mg/kg, i.v.) combined with diazepam (1.25 mg/kg, i.p.) could increase LD50 of p. o. SCD 5.3 times. DMPS (62.5 mg/kg, i.v.) antagonized completely the respiratory depression and neuromuscular blockade caused by SCD(7.5 mg/kg, i.v.) in rabbits. SCD (15 mg/kg, i.v.) caused tremor, tonic convulsion and the abnormal paroxysmal discharges in EEG in rabbits. DMPS (0.5 mg/kg, i.c.v) could not eliminate the abnormal paroxysmal discharges in EEG of rabbits. DMPS (62.5 mg/kg, i.v.) combined with diazepam (5 mg/kg, i.v.) completely and rapidly antagonize these toxic symptoms and the abnormal changes in EEG.

Cleavage of concatemeric DNA at the internal junction of "translocation" mutants of pseudorabies virus and inversion of their L component appear to be linked

When pseudorabies virus (PrV) strains are grown in chicken embryo fibroblasts (CEF), variants ("translocation" mutants) arise in which there is a duplication of the leftmost sequences of the genome and their translocation in inverted orientation next to the internal inverted repeat bracketing the S component. In these variants, the UL becomes bracketed by inverted repeats and is found in two orientations relative to the Us. To study the cis-functions involved in cleavage of concatemeric DNA as well as those involved in inversion of the L component and to ascertain whether the two events are linked in the "translocation" mutants, a viral mutant (vLD68) was constructed in which the terminal 64 bp of the L component (that include sequences with homology to the pac 2 site of HSV) and the 4 terminal bp of the S component were deleted from the internal junction. Although revertants that have acquired the 68 bp at the internal junction emerge rapidly in populations of vLD68, analysis of the characteristics of this mutant revealed that: (1) the termini derived from both orientations of the L component include the 64 bp that have been deleted from the internal junction of vLD68; (2) in contrast to other "translocation" mutants, the internal junction of the vLD68 genome is not a good substrate for cleavage; (3) inversion of the L component of true vLD68 DNA does not occur or is rare; a good correlation exists in the populations of vLD68 between the proportion of revertants that have acquired an intact internal junction and the proportion of genomes with an L component that inverts. These results show that an intact internal junction in "translocation" mutants is necessary for both inversion of their L components and cleavage at their alternative internal junction. Since cleavage at the alternative junction will result in inversion of the L component, we conclude that inversion of the L component of "translocation" mutants of PrV can be attributed to cleavage of concatemeric DNA at the internal alternative junction.

Acquisition of an additional internal cleavage site differentially affects the ability of pseudorabies virus to multiply in different host cells

The translocation of the 325 leftmost bp of the genome of pseudorabies virus (PrV) to the internal junction between the L and S components confers upon the virus a growth advantage relative to wild-type PrV in chicken embryo fibroblasts (CEFs) and chickens and a growth disadvantage in rabbit kidney (RK) cells and mice. To clarify the molecular basis for the species-specific growth characteristics of the translocation mutants, we have compared several parameters of the virus growth cycle in CEFs and RK cells infected with wild-type PrV and with translocation mutants. The salient findings are as follows. (i) The synthesis of early-late and late proteins is not as effective in CEFs as it is in RK cells, and these proteins, in particular, the major capsid proteins, accumulate less abundantly in CEFs than in RK cells. (ii) Cleavage of concatemeric DNA to genome-size molecules is also not as effective in CEFs as it is in RK cells. (iii) The internal junction present in translocation mutants is a functional cleavage site. (iv) In RK cells, translocation mutants are hypercleaved and a significant proportion of the total viral DNA is cleaved into subgenomic fragments. (v) In CEFs infected with translocation mutants, subgenomic fragments also accumulate but most of the viral DNA remains in concatemeric form. A model which postulates that the cell-specific growth advantage or disadvantage of the translocation mutants is related to the presence of a second cleavage site within their genomes and is affected by the efficiency of cleavage of concatemeric DNA in particular infected cell types is presented. The significance of these findings as they relate to the evolution of herpesviruses with class 2- and class 3-like genomes is discussed.

Analysis of an origin of DNA replication located at the L terminus of the genome of pseudorabies virus

We have localized an origin of DNA replication at the L terminus of the pseudorabies virus genome. This origin differs in location as well as in general structure from the origins of replication of other herpesviruses that have been identified. The 600 leftmost nucleotides of the genome that were found to include origin function have been analyzed. This sequence is composed of an 82-bp palindrome whose center of symmetry is separated by 352 unique bp (UL2). Within the UL2, a sequence that fits the consensus sequence of the NF1 binding site, as well as one that has partial homology to the binding site of UL9 of herpes simplex virus, is present. Using truncated fragments of DNA, sequences essential for minimal origin function were delimited to within a fragment that includes the terminal 104 bp of the left end of the genome. Within these 104 bp, two elements essential to origin function have been identified. One of these elements is present within the terminal 64 bp of the L component (within one of the palindromic arms). The other is present within the 22 bp of the UL2 adjacent to this palindromic arm. Other auxiliary elements, although not essential for origin function, contribute to more efficient replication. The NF1 and UL9 binding site homologies were found to be nonessential to origin function.

Inhibition of methyl methanesulfonate-induced unscheduled DNA synthesis in spermatozoa of mice by Poly I-C

Methyl methanesulfonate (MMS 75 mg.kg-1)-induced unscheduled DNA synthesis (UDS) was inhibited significantly in the spermatozoa of mice injected with Poly I-C (0.05, 0.50, and 5.00 mg.kg-1) at 4 h prior to ip MMS. Radioactivity was reduced from 53 +/- 3 to 50, 45 +/- 5, and 34 +/- 6 dpm/million sperms respectively. The effects of Poly I-C were dose-dependent (r = 0.9498, P less than 0.05) in inhibition of MMS-induced UDS. The effect of serum collected from the mice injected with Poly I-C (0.50 mg.kg-1) had similar effects as that of Poly I-C. Our findings suggest that both Poly I-C alone and mouse serum induced with Poly I-C may prevent the DNA damage produced by MMS.

Structural organization of the termini of the L and S components of the genome of pseudorabies virus

The sequences of several hundred nucleotides around the junctions between the L and S components in concatemeric DNA and in mature virion DNA were ascertained. The two ends of the mature genome (which are joined in concatemeric DNA) show no sequence homology. Several directly repeated elements are present near both ends of the genome. Furthermore, the last 82 nucleotides at the left end of the L component (and of the genome) are repeated in inverted form (inverted repeat within the L component [IRL]) approximately 350 to 600 nucleotides downstream (depending on the virus isolate) bracketing the UL2 component. A comparison between the sequences at the right and left ends of the L component of the genome showed patchy homology, probably representing a vestigial inverted repeat bracketing the L component (IRL). Furthermore, less than 5% of the genomes have an L component that is in the orientation opposite to that of most of the viral genomes, indicating that the vestigial IRL that brackets the UL sequence may be sufficient to mediate inversion of the L component in some of the genomes. On the other hand, the UL2 component, which is bracketed by a perfect IRL, does not invert to a greater extent than does the L component (if it inverts at all). Analysis of the nucleotide sequence at the concatemeric junction of three different pseudorabies virus isolates showed almost complete sequence conservation. The sequence and organization of the repeated elements in the different isolates were almost identical, despite their different histories and origins. The high degree of conservation of these repeated elements implies that they may fulfill an essential function in the life cycle of the virus.

[Effects of nicardipine and chlorpromazine on proliferation and intracellular calmodulin in cultured aortic smooth muscle cells]

Effects of Ca2+ and calcium antagonists nicardipine (Nic) and chlorpromazine (CPZ) on the proliferation, DNA synthesis and intracellular calmodulin (CaM) levels in cultured rabbit aortic smooth muscle cells were investigated. Maximal response of cell to Ca2+ stimulation occurred in the normal medium with CaCl2 1.4 mmol/L, whereas CaCl2 0.02-0.6 mmol/L, Nic (2.5-40.0 mumol/L) and CPZ (5.0-20.0 mumol/L) inhibited the cell proliferation in a concentration-dependent manner. The additive effects of Nic and CPZ were observed. There was a transient surge of intracellular soluble CaM level at 9h in late G1 phase of the cell cycle just before the initiation of DNA synthesis. Not only the initiation of DNA synthesis but also the CaM surge were prevented by adding Nic or CPZ (20-40 mumol/L) to media. These results suggest that an appropriate extracellular Ca2+ concentration was required for aortic smooth muscle cells to grow normally. Since calcium antagonists influenced the intracellular Ca2+ pool by blockade of calcium channel and they inhibited the CaM function directly by anticalmodulin activity or indirectly through altered intracellular Ca2+ metabolism, intracellular Ca2+ and CaM levels may be involved in the effects of Nic and CPZ on the proliferation and DNA synthesis.

Nucleotide sequences at recombinational junctions present in pseudorabies virus variants with an invertible L component

The genome of pseudorabies virus (PrV) consists of two components--a noninvertible long (L) and an invertible short (S) component. The S component is bracketed by inverted repeats. In some variant strains of PrV (which have a selective growth advantage in certain cell lines), a sequence normally present at the left end of the L component has been translocated to the right end of the L component next to the inverted repeat. Consequently, these strains have acquired a genome with an L component that is bracketed by inverted repeats and that also inverts. We have determined the restriction maps and have analyzed the nucleotide sequences of those parts of the genome of three strains with invertible L components that contain the translocated segment of DNA. The results were as follows. The translocated fragments were derived in all cases from the extreme left end of the L component only. The sizes of the translocated fragments were similar, ranging from 1.3 to 1.4 kilobase pairs. The junction between the L and S components in these strains was the same as that in standard viral concatemeric DNA. The translocation of sequences from the left end of the genome next to the inverted repeats was always accompanied by a deletion of sequences from the right end of the L component. The sizes of the deleted fragments varied considerably, ranging from 0.8 to 2.3 kilobase pairs. Sequence homology at the points of recombination, i.e., at the junction between the right end and the left end of the L component, existed sometimes but not always. A model depicting how a virus with a class 2 genome (such as PrV) may acquire a genome with characteristics of a class 3 genome (such as herpes simplex virus) is presented.

Ginseng extract inhibits protein degradation and stimulates protein synthesis in human fibroblasts

Aqueous extracts of Panax ginseng inhibit intracellular protein degradation in confluent cultures of IMR-90 human diploid fibroblasts. The magnitude of the inhibition is similar to that observed with insulin and polypeptide growth factors. Furthermore, the inhibition of proteolysis by ginseng, like that produced by insulin and growth factors, is selective in that it applies to long-lived proteins but not to short-lived proteins. Ginseng also stimulates protein synthesis in human fibroblasts indicating that components of ginseng extract are capable of acting directly on human cells to promote protein accumulation.

Diffraction tomography using beam waves: z-average reconstruction

This paper discusses the problem of diffraction tomography, when a general beam wave is used as the excitation and the three-dimensional structure of the object is considered. The special case of a zero-order beam wave with measurements of the average of the scattered field in the z direction is detailed. It is shown that in this case a reconstruction algorithm identical to the two-dimensional geometry yields a z-averaged tomogram of the inhomogeneity.