[Twelve-week of sofosbuvir/velpatasvir therapeutic regimen for chronic hepatitis C patients in northwest region of China: a real-world multicenter clinical study]

Objective: To study the real-world outcome of China FDA-approved Sofosbuvir (SOF)/Velpatasvir (VEL) in Northwest China. Methods: In this multicenter, prospective, real-world cohort study, we recruited patients from 10 sites from Northwest China, who were chronically infected with HCV GTs 1-6 from 06/2018 to 09/2019. Patients received SOF (400mg)/VEL (100mg) for 12 weeks, and with ribavirin 900-1200 mg for GT3 cirrhosis and for any genotype decompensated cirrhosis. The primary endpoint was sustained virological response at 12-weeks post-treatment (SVR12) and safety. The secondary endpoint was the change of liver function after the achievement of SVR12. Results: Totally, 143 patients were enrolled in the study, four patients were lost to follow-up and one died during the follow-up, 138 patients were included in per-protocol analysis. Of the 138 patients, the mean age 53 years, 53.6% male, 94.2% Han nationality, 53.6% liver cirrhosis, 10.1% HBsAg(+), 6.5% renal dysfunction, 5.1% treatment-experienced, and 16.7% patients received ribavirin treatment. The genotype distribution was as follows: 35.5% GT1, 42.8% GT2, 15.9% GT3, and 5.8% un-typed. The SVR12 rate was 96.5% (138/143, 95%CI: 93.5%-99.6%) for intention-to-treat analysis, and in per-protocol analysis, all 138 patients obtained SVR12 (100%). Compared with baseline, the serum total bilirubin, ALT and AFP levels decreased (all P < 0.05), as well as increased ALB and platelet count (all P < 0.001) at post-treatment 12-weeks. Overall adverse events (AEs) rate is 29.0%, and the most common AEs were anemia (14.5%) and fatigue (8.0%). Severe side effects (edema and fatigue) occurred in 2 patients, one of whom needed a short-term interruption of treatment due to fatigue. Conclusion: In this real-world cohort study, 12-week SOF/VEL regimen with or without ribavirin achieved high SVR12 rates (96.5%-100% overall) with excellent safety profile among patients with HCV GT1/2/3 infection including patients with GT3 and cirrhosis, and led to improvement of liver function.

An improved DNA marker technique for genetic characterization using RAMP-PCR with high-GC primers

Random amplified polymorphic DNA (RAPD) is a widely used molecular marker technique. As traditional RAPD has poor reproducibility and productivity, we previously developed an improved RAPD method (termed RAMP-PCR), which increased the reproducibility, number of bands, and efficiency of studies on polymorphism. To further develop the efficiency of this method, we used high-GC content primers for improved RAMP-PCR with DNA samples from Lonicera japonica. Comparison of amplification profiles obtained by standard RAPD primers with those obtained by regular PCR and RAMP-PCR, and high-GC primers with regular PCR and RAMP-PCR showed that the average number of bands and polymorphisms per primer gradually and significantly increased (from 6.4 to 15.0 and from 4.6 to 10.2, respectively). Cluster dendrograms showed similar results, indicating that this new method is consistent and reproducible. A total of 22 samples from different species, including plants, animals, and humans, were used for RAMP-PCR with high-GC primers. Multiple bands were successfully amplified from all samples, demonstrating that this method is a reliable technique with consistent results and may be of general interest in studies on different genera and species. We developed highly effective DNA markers, which can provide a more effective and potentially valuable approach than traditional RAPD for the genetic identification of various organisms, particularly of medicinal plants.

Development and significance of SCAR marker QG12-5 for Canarium album (Lour.) Raeusch by molecular cloning from improved RAPD amplification

Sequence-characterized amplified region (SCAR) is a valuable molecular marker for the genetic identification of any species. This marker is mainly derived from molecular cloning of random amplified polymorphic DNA (RAPD). We have previously reported the use of an improved RAPD technique for the genetic characterization of different samples of Canarium album (Lour.) Raeusch (C. album). In this study, DNA fragments were amplified using improved RAPD amplified from different samples of C. album. The amplified DNA fragment was excised, purified from an agarose gel and cloned into a pGM-T vector; subsequently, a positive clone, called QG12-5 was identified by PCR amplification and enzymatic digestion and sequenced by Sanger di-deoxy sequencing method. This clone was revealed consisting of 510 nucleotides of C. album. The SCAR marker QG12-5 was developed using specifically designed PCR primers and optimized PCR conditions. This SCAR marker expressed seven continuous "TATG" [(TATG)n] tandem repeats, which was found to characterize C. album. Subsequently, this novel SCAR marker was deposited in GenBank with accession No. KT359568. Therefore, we successfully developed a C. album-specific SCAR marker for the identification and authentication of different C. album species in this study.

Development of two novel specific SCAR markers by cloning improved RAPD fragments from the medicinal mushroom Ganoderma lucidium (Leysser: Fr) Karst

Development of sequence-characterized amplified region (SCAR) markers from random-amplified polymorphic DNA (RAPD) fragments is a valuable molecular approach for the genetic identification of different species. By using SCAR markers, molecular analysis is reduced to a simple polymerase chain reaction (PCR) analysis using primers designed from the amplicon sequence of RAPD. In this study, the DNA fragments from an improved RAPD amplification of Ganoderma species were cloned into a pGM-T vector; positive clones were identified by PCR amplification and enzymatic digestion, and finally, DNA fragments were sequenced using the Sanger sequencing method for developing the SCAR markers. Two SCAR markers, named LZ4-1 with 534 nucleotides, and LZ5-2 with 337 nucleotides were identified, which are specific to Ganoderma lucidium (Leysser: Fr) Karst species. BLAST of these two nucleotide sequences in the GenBank database showed no identity to other species. We deposited these sequences into the GenBank database (LZ4-1 accession No. KM391933, LZ5-2 accession No. KM391934). PCR assays confirmed them as novel molecular markers for G. lucidium (Leysser: Fr) Karst, which might be used for genetic authentication of adulterant samples. Thus, our study developed two specific SCAR markers for identifying and distinguishing the medicinal mushroom G. lucidium (Leysser: Fr) Karst from other Ganoderma species.

Development of novel SCAR markers for genetic characterization of Lonicera japonica from high GC-RAMP-PCR and DNA cloning

Sequence-characterized amplified region (SCAR) markers were further developed from high-GC primer RAMP-PCR-amplified fragments from Lonicera japonica DNA by molecular cloning. The four DNA fragments from three high-GC primers (FY-27, FY-28, and FY-29) were successfully cloned into a pGM-T vector. The positive clones were sequenced; their names, sizes, and GenBank numbers were JYHGC1-1, 345 bp, KJ620024; YJHGC2-1, 388 bp, KJ620025; JYHGC7-2, 1036 bp, KJ620026; and JYHGC6-2, 715 bp, KJ620027, respectively. Four novel SCAR markers were developed by designing specific primers, optimizing conditions, and PCR validation. The developed SCAR markers were used for the genetic authentication of L. japonica from its substitutes. This technique provides another means of developing DNA markers for the characterization and authentication of various organisms including medicinal plants and their substitutes.

[Effect of thermo-sensitive Matrigel on minimization of thermal injury to the nearby structures in radiofrequency ablation of subcapsular hepatic tumors in a rat model]

OBJECTIVE

To evaluate the effect and safety of using thermo-sensitive Matrigel as artificial ascites on minimizing thermal injury to the nearby structures in a rat model of radiofrequency (RF) ablation of the liver.

METHODS

In this research, the morphological characterization of Matrigel was observed at different temperatures in vitro. In vivo study was conducted by using 42 SD rats in Matrigel, Saline and control groups of 14 rats each. Artificial ascites with 10 ml of Matrigel or saline was produced under ultrasound guidance before RF in the experimental groups. Using a 0.7 cm exposed 17 G RF electrode for 5 minutes (90 ± 2) ℃, 41 hepatic ablations was performed abutting the diaphragm, abdominal wall and stomach. The 41 rats were sacrificed at 24 h, and necropsy was performed.Gross and histopathologic examinations were performed to compare the frequency and extent of thermal injury to the nearby organs.The animal status was followed up to achieve long term safety evaluation of Matrigel.

RESULTS

Matrigel was in liquid formation at 0-4 ℃, but was not moving in vials at temperature 37 ℃ in 1 min, presenting gel formation.In vivo experiment, the artificial fluid thickness of Matrigel in site was significant larger than that of saline group, especially at 5 min of ablation ((8.1 ± 1.1) mm vs (2.4 ± 0.8)mm, P<0.01). Thermal injury to the nearby structures was found in 12 of 13 cases in control group, 8 of 14 cases (P=0.037) in saline group, and 1 of 14 cases (P<0.01) in Matrigel group. The sizes of the ablation zone of the liver did not differ among the three groups. There was no difference in the incidence of operation related complications among the three groups. There was no significant difference in body weight and health related parameters between Matrigel and saline group during 60 days of follow up.

CONCLUSIONS

Using thermo-sensitive Matrigel as artificial ascites may be a safe and useful technique and help to further reduce the frequency and severity of collateral thermal injury to the nearby structures compare to conventional saline, during RF ablation of subcapsular hepatic tumors.

Isolation and analysis of cell-free fetal DNA from maternal peripheral blood in Chinese women

Non-invasive prenatal diagnosis is used to detect the genetic material of the fetus by isolating the cell-free fetal DNA (cffDNA) from maternal peripheral blood. In order to establish an isolation method for cffDNA from maternal peripheral blood in Chinese women, the cffDNA was acquired with a two-step centrifugation using a QlAamp DNA Blood mini kit. The SRY gene of plasma DNA was amplified by polymerase chain reaction (PCR). Real-time quantitative PCR was used to measure the concentration of cffDNA in maternal peripheral blood in different pregnant women. The results of the SRY gene amplification of plasma DNA from pregnant women was the same as that of the amniocyte DNA. The average concentration of cffDNA in maternal peripheral blood of pregnant women in different gestational stages was 0.98 ng/mL (0.26-1.49 ng/mL), 1.43 ng/mL (0.46- 2.34 ng/mL), and 1.95 ng/mL (0.65-6.81 ng/mL) from early, middle, and late gestational stages, respectively. The mean of cffDNA from total DNA in plasma in different stages of gestation was 22.28% (9.86-27.81%). The lowest concentration of DNA amplified by nested-PCR in our research was 10-4-10-3 ng/μL. The isolation method for cffDNA from maternal peripheral blood was successfully established and further research into its applications will be conducted.

Identification of the origin of marker chromosomes by two-color fluorescence in situ hybridization and polymerase chain reaction in azoospermic patients

Y chromosomal microdeletions at the azoospermia factor locus and chromosome abnormalities have been implicated as the major causes of idiopathic male infertility. A marker chromosome is a structurally abnormal chromosome in which no part can be identified by cytogenetics. In this study, to identify the origin of the marker chromosomes and to perform a genetic diagnosis of patients with azoospermia, two-color fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR) techniques were carried out. The marker chromosomes for the two patients with azoospermia originated in the Y chromosome; it was ascertained that the karyotype of both patients was 46,X, ish del(Y)(q11)(DYZ3+, DXZ1-). The combination of two-color FISH and PCR techniques is an important method for the identification of the origin of marker chromosomes. Thus, genetic counseling and a clear genetic diagnosis of patients with azoospermia before intracytoplasmic sperm injection or other clinical managements are important.

Relationship between SPOP mutation and breast cancer in Chinese population

SPOP protein has been found to have ubiquitin ligase activity. Mutations in SPOP gene have been recently reported in some cancers such as prostate, gastric, colorectal cancer. We investigated SPOP DNA mutation in tumor tissues collected from 70 Chinese female breast cancer patients in Southwestern China by DNA sequencing. The results did not show mutation in our tissue samples, indicating that a mutation in the SPOP gene may not be associated with breast cancer, particularly in Chinese women. This DNA mutation analysis or DNA genotyping may provide useful and important information for genetic counseling and personalized medical treatment for different types of cancers.

Establishment and rapid detection of a heterozygous missense mutation in the CACNA1F gene by ARMS technique with double-base mismatched primers

Retinitis pigmentosa (RP) is a retinal degenerative disorder that often causes complete blindness. Mutations of more than 50 genes have been identified as associated with RP, including the CACNA1F gene. In a recent study, by employing next-generation sequencing, we identified a novel mutation in the CACNA1F gene. In this study, we used the amplification refractory mutation system (ARMS) and identified a single nucleotide change c.1555C>T in exon 13 of the CACNA1F gene, leading to the substitution of arginine by tryptophan (p.R519W) in a Chinese individual affected by RP. This study actually confirms this novel mutation, and establishes the ARMS technique for the detection of mutations in RP.

Development of RAPD-SCAR markers for different Ganoderma species authentication by improved RAPD amplification and molecular cloning

The sequence-characterized amplified region (SCAR) is a valuable molecular technique for the genetic identification of any species. This method is mainly derived from the molecular cloning of the amplified DNA fragments achieved from the random amplified polymorphic DNA (RAPD). In this study, we collected DNA from 10 species of Ganoderma mushroom and amplified the DNA using an improved RAPD technique. The amplified fragments were then cloned into a T-vector, and positive clones were screened, indentified, and sequenced for the development of SCAR markers. After designing PCR primers and optimizing PCR conditions, 4 SCAR markers, named LZ1-4, LZ2-2, LZ8-2, and LZ9-15, were developed, which were specific to Ganoderma gibbosum (LZ1-4 and LZ8-2), Ganoderma sinense (LZ2-2 and LZ8-2), Ganoderma tropicum (LZ8-2), and Ganoderma lucidum HG (LZ9-15). These 4 novel SCAR markers were deposited into GenBank with the accession Nos. KM391935, KM391936, KM391937, and KM391938, respectively. Thus, in this study we developed specific SCAR markers for the identification and authentication of different Ganoderma species.

Field evidence for earlier leaf-out dates in alpine grassland on the eastern Tibetan Plateau from 1990 to 2006

Worldwide, many plant species are experiencing an earlier onset of spring phenophases due to climate warming. Rapid recent temperature increases on the Tibetan Plateau (TP) have triggered changes in the spring phenology of the local vegetation. However, remote sensing studies of the land surface phenology have reached conflicting interpretations about green-up patterns observed on the TP since the mid-1990s. We investigated this issue using field phenological observations from 1990 to 2006, for 11 dominant plants on the TP at the levels of species, families (Gramineae-grasses and Cyperaceae-sedges) and vegetation communities (alpine meadow and alpine steppe). We found a significant trend of earlier leaf-out dates for one species (Koeleria cristata). The leaf-out dates of both Gramineae and Cyperaceae had advanced (the latter significantly, starting an average of 9 days later per year than the former), but the correlation between them was significant. The leaf-out dates of both vegetation communities also advanced, but the pattern was only significant in the alpine meadow. This study provides the first field evidence of advancement in spring leaf phenology on the TP and suggests that the phenology of the alpine steppe can differ from that of the alpine meadow. These findings will be useful for understanding ecosystem responses to climate change and for grassland management on the TP.

Genetic characterization and authentication of Dimocarpus longan Lour. using an improved RAPD technique

Dimocarpus longan Lour. is an edible and traditional herb in China, commonly referred to as longon. An improved randomly amplified polymorphic DNA (RAPD) protocol was here developed in order to determine the geographical origins of D. longan samples collected from 5 provinces in the southern and southwestern areas of China, including Sichuan, Hainan, Fujian, Guangdong, and Guangxi. Generally, the improved RAPD method generated good fingerprinting of the 5 samples using the selected 17 primers. In particular, primers SBS-A5, SBS-A13, SBS-I9, SBS-I20, SBS-M1, and SBS-Q12 produced distinguishable bands that clearly separated all 5 cultivars, suggesting that there are variations in RAPD genetic sites among the samples. The similarity index ranged from 0.69 to 0.76. The Sichuan and Hainan clades clustered together with a 0.73 similarity index. The Guangxi and Fujian clades clustered together with a 0.76 similarity index, and they formed the sister clade to the Sichuan/Hainan clade with a 0.71 similarity index. The Guangdong clade was in a basal polytomy with a 0.70 similarity index. Based on the abundant DNA polymorphisms, these longan accessions are distinguishable using our improved RAPD technique. Therefore, RAPD analysis is an effective technique in distinguishing the geographical origins of D. longan. Moreover, the improved method could also be employed for a variety of applications including genetic diversity and fingerprinting analyses.

[Rapid identification of human testis spermatocyte apoptosis-related gene, TSARG2, by nested PCR and draft human genome searching]

Cloning apoptosis-related novel genes is a key to further understanding of apoptosis mechanism and the biology process of germ cells, and is of momentous significance on clarifying physiological and pathological process of spermatogenesis. To rapidly attain human novel gene full-length cDNA sequence, the gene-specific primers and the vector-specific primers were designed for nested PCR, and draft human genome searching was performed to rapidly identify the TSARG2 (GenBank accession number AY040204) 5' end from a human testis cDNA library, by using a cDNA fragment (GenBank accession number BE644542) as an electronic probe, which was significantly changed in cryptorchidism and represented a novel gene. Furthermore, a mouse homologue of this gene was identified (GenBank accession number AF395083) by lab on-line. TSARG2 with a 1 233 bp length was composed of 6 exons and spanned about 115 kb of genomic DNA, The putative protein encoded by this gene was 305 amino acid with a theoretical molecular weight of 34 751 dalton and did not share significant homology with any known protein in databases. TSARG2 was expressed in many tissues and mapped to chromosome 4q33-34.1 by database analyses. Therefore, we propose that nested-PCR and draft human genome searching are rapid, sensitive, accurate and efficient method for isolating gene 5' end, even full-length gene from cDNA library.

[Molecular cloning of one splicing form of human M6b cDNA]

X-linked, early onset Pelizaeus-Merzbacher disease (PMD) and part of X-linked spastic paraplegia are caused by mutation of proteolipid protein. M6b (U45955) partially cloned by Olinsky was considered as a member of PLP gene family. One novel fragment about 300 bp partially overlapped but differed in 5'part with U45955 was obtained by nested PCR. Assembly of the novel sequence with U45955 make a 1.642kb cDNA sequence with an open reading frame encoding 265 amino acids, which was verified by sequence of PCR products from brain cDNA library. The cDNA (termed M6ba) and its deduced peptide sequence showed significant similarity to murine M6b gene and protein (91.2% and 93.4% respectively). Northern blot, PCR amplification in cDNA library and EST analysis indicated that human M6b gene has at least three splicing forms. M6ba also showed significant similarity to PLP gene, they encode strongly hydrophobic protein and all their hydrophobic region are highly conserved. Gene structure analysis showed that the coding region of M6ba was composed of seven exons.

Gastric emptying rate assessment based on the proportion of intra-abdominal radioactivity in the stomach

Using scintigraphic techniques, the rate of gastric emptying is calculated by quantifying the absolute radioactivity within a gastric region of interest (intragastric method) with the time of meal completion considered 100% retention. However, this technique has significant limitations arising from subject movement and radionuclide gamma-ray attenuation, which may render curve fitting difficult, particularly in patients with gastroparesis. In an attempt to minimize these limitations, we have expressed the intragastric content as a percentage of the total abdominal radioactivity (abdominal method) and compared these two methods.

METHODS

Forty-five subjects in a sitting position consumed a meal consisting of two fried eggs labeled with 99mTc, two slices of toast and 300 mL 5% glucose water (412 kcal). Data were acquired at a rate of one frame every 5 min from the left anterior oblique view. Using the two methods, the intragastric retention ratios at 30, 60, 90, 120 and 240 min and the 50% emptying time (T50) were obtained from both observation and calculation by power exponential fit. R2, representing goodness of fit of the nonlinear curve fitting, was calculated.

RESULTS

There were no differences in the calculated values of T50 between the two methods. Quantitative estimates of T50 by extrapolation of a power exponential fit were feasible in 42 of the 45 subjects when the abdominal method was used, compared with only 29 of the 45 subjects when the intragastric method was used. In the 23 subjects with delayed emptying, quantitative estimates of T50 were feasible in 20 subjects when the abdominal method was used, compared with 7 subjects when the intragastric method was used. Using the abdominal method as opposed to the intragastric method also significantly improved R2. The difference between observed values and estimated values of T50 and intragastric retention ratios at 30, 90 and 120 min was smaller using the abdominal method.

CONCLUSION

Scintigraphic measurement of gastric emptying calculated using the proportion of the abdominal radioactivity in the stomach offers substantial advantages over conventional methods, particularly in patients with gastroparesis.

[Identification of the origin of 7q+ marker chromosome in a mental retard patient]

The present chromosome-specific and chromosome-band-specific probe pools constructed by the technique of human chromosome microdissection and PCR were taken as painting probes. Using the forward chromosome painting and chromosome screening method, we had identified a chromosome additional fragment of a 7 q+ marker chromosome in a patient originated from 3 q 26-->3 qter, and ascertained the patient's karyotype was 46, XX, -7, + der (7) t (7;3) (7 pter-->7 q 32::3 q 26-->3 qter). Applying this strategy, we can identify the origin of marker chromosomes fastly and effectively.

Unilateral injury of posterior parietal cortex and spatial learning in hooded rats

The influences of bilateral or unilateral injuries within the posterior parietal cortex (PPC) upon spatial learning in a water maze were examined in three experiments. Place-learning and response-learning were investigated in a four-alley 'Greek-cross' shaped water maze with extra-maze visual cues available. No differences were detected on any of several measures sensitive to learning between the lesion groups on the place-learning task. Microanalysis of behavior within trials revealed that animals with either bilateral or right unilateral PPC injuries committed significantly more total errors, initial alley entrance ('reference memory') errors, and re-entry ('working memory') errors in the response-learning paradigm than did either the control or left PPC-injured rats. No differences were detected between the latter two groups on these measures. Unilateral lesions resulted in asymmetrical placing responses ipsilateral to the injury 10 days after surgery whereas bilateral injuries resulted in asymmetrical placing with mixed directionality. The acquisition of the response-learning problem in the absence of visual cues was studied on animals prepared with unilateral lesions and housed post-operatively either in isolation or in a 'complex environment.' In the absence of visual cues both right and left PPC-injured rats committed more errors than sham controls, and differential post-surgical housing did not attenuate these impairments. These same animals were trained on the landmark navigation task. Although no differences appeared between the lesion groups, a generalized but transient facilitation of learning was observed in animals housed in the 'complex' environment. Unilateral injuries placed in sham controls failed to disturb retention of the landmark navigation strategy. Because none of the PPC-injured animals were deficient in the landmark task, a result which is contrary to observations in other laboratories, the influence of post-surgical recovery interval upon acquisition of the landmark navigation strategy was explored. Animals were prepared with right PPC injuries and trained following either a 5 or 35 day recovery interval. Only those animals limited to the short recovery interval proved to have a spatial deficit in the landmark task. It is concluded that injuries in the PPC of either hemisphere disturb egocentric spatial functions. However, animals with left PPC injuries are able to compensate by using allocentric visual cues if they are available. It is due to the special role played by the right PPC in complex visuospatial functions that animals with this injury are unable to compensate.

A visuospatial dysfunction following posterior cortex injury is attenuated by postinjury administration of the ACTH4-9 analog ORG 2766

Rats were trained in a Y-shaped water maze to discriminate a light gray from a medium gray visual stimulus. The latter stimulus card cued the location of a nonvisible escape platform. The animals received either a sham operation or a large ablation in the posterior neocortex, and osmotic minipumps were implanted subcutaneously in the animal's back. The pumps chronically administered either saline or ORG 2766 at a rate of 0, 1, or 10 micrograms per 24 h for 14 days while the animals recovered in individual rat cages. Four weeks after surgery retention of the discrimination was tested and, for those reattaining criterion, transposition of the habit to a pairing of the medium gray card with a black stimulus card was assessed. Animals treated with 10 micrograms ORG 2766 reattained criterion on the original discrimination more rapidly than did animals treated with 0 or 1 microgram. Neither the lesion nor the drug resulted in consistent influences upon transposition. There was no evidence that the drug protected neurons within the dorsal lateral geniculate nuclei. Postinjury treatment with some doses of ORG 2766 can attenuate the severity of some dysfunctions that accompany neurotrauma by influencing the development of behavioral compensation.

[Construction and application of the chromosomal specific probe pool from human chromosome no. 7]

We constructed a chromosomal specific probe pool from human chromosome No. 7 using the techniques of chromosomal microdissection, PCR and chromosomal painting. A patient's pedigree with an abnormal chromosome No. 7 were analysed by the above probe pool.

Protective effect of topically applied conjugated hexadienes against ultraviolet radiation-induced chronic skin damage in the hairless mouse

Albino hairless mice (SkH:HR-1) exposed chronically to suberythemal doses of ultraviolet B (UVB) radiation display visible skin wrinkling and tumors. Topical treatment of mice with solutions of conjugated dienes (2,4-hexadien-1-ol and derivatives of it) prior to each UVB radiation exposure reduces significantly the severity of these visible alterations. Chronic suberythemal doses of ultraviolet A radiation induce skin sagging, a distinctly different visible skin alteration. The severity of skin sagging is not reduced by topical application of the conjugated dienes tested here.