[Real-world study on the efficacy and safety of first-line antiviral therapy for chronic hepatitis B]

Objective: To clarify the clinical efficacy of first-line oral antiviral drugs tenofovir alafenamide (TAF), tenofovir disoproxil fumarate (TDF), and entecavir (ETV) in the treatment of chronic hepatitis B (CHB) and their safety profiles with lipid, bone, and kidney metabolism. Methods: 458 CHB cases diagnosed and treated at the Department of Hepatology of Integrated Traditional Chinese and Western Medicine of the Third Hospital of Hebei Medical University from February 2010 to November 2022 were selected. TAF (175 cases), TDF (124 cases), and ETV (159 cases) were used as therapies. At 24 and 48 weeks, the virology, biochemical response, changes in liver stiffness measurement (LSM), and bone, kidney, and blood lipid metabolism safety profiles were compared and analyzed. Results: After 24 and 48 weeks of TAF, TDF, and ETV therapy, HBV DNA load decreased by 3.28, 2.69, and 3.14 log10 IU/ml and 3.28, 2.83, and 3.65 log10 IU/ml, respectively, compared with the baseline, and the differences between the three groups were statistically significant, P < 0.001. The complete virological response rates were 73.95%, 66.09%, 67.19%, and 82.22%, 72.48%, and 70.49%, respectively. The incidence rates of low-level viremia were 16.67%, 21.70%, and 23.08%, while poor response rates were 1.11%, 3.67%, and 4.10%. ALT normalization rates were 64.00%, 63.89%, 67.96%, and 85.33%, 80.56%, 78.64%, respectively, and there was no statistically significant difference among the groups. LSM was significantly improved in patients treated with TAF for 48 weeks, P = 0.022. Serum phosphorus level gradually decreased with the prolongation of TDF treatment. The TAF treatment group had a good safety profile for kidney, bone, and phosphorus metabolism, with no dyslipidemia or related occurrences of risk. Conclusion: There are some differences in the therapeutic effects of first-line anti-HBV drugs. TAF has the lowest incidence of low-level viremia after 48 weeks of treatment and has a good safety profile in kidney, bone, and blood lipid metabolism.

[Clinical value of plasma scaffold protein SEC16A in evaluating hepatitis B-related liver cirrhosis and hepatocellular carcinoma]

Objective: To investigate the clinical value of plasma scaffold protein SEC16A level and related models in the diagnosis of hepatitis B virus-related liver cirrhosis (HBV-LC) and hepatocellular carcinoma (HBV-HCC). Methods: Patients with HBV-LC and HBV-HCC and a healthy control group diagnosed by clinical, laboratory examination, imaging, and liver histopathology at the Third Hospital of Hebei Medical University between June 2017 and October 2021 were selected. Plasma SEC16A level was detected using an enzyme-linked immunosorbent assay (ELISA). Serum alpha-fetoprotein (AFP) was detected using an electrochemiluminescence instrument. SPSS 26.0 and MedCalc 15.0 statistical software were used to analyze the relationship between plasma SEC16A levels and the occurrence and development of liver cirrhosis and liver cancer. A sequential logistic regression model was used to analyze relevant factors. SEC16A was established through a joint diagnostic model. Receiver operating characteristic curve was used to evaluate the clinical efficacy of the model for liver cirrhosis and hepatocellular carcinoma diagnosis. Pearson correlation analysis was used to identify the influencing factors of novel diagnostic biomarkers. Results: A total of 60 cases of healthy controls, 60 cases of HBV-LC, and 52 cases of HBV-HCC were included. The average levels of plasma SEC16A were (7.41 ± 1.66) ng/ml, (10.26 ± 1.86) ng/ml, (12.79 ± 1.49) ng /ml, respectively, with P < 0.001. The sensitivity and specificity of SEC16A in the diagnosis of liver cirrhosis and hepatocellular carcinoma were 69.44% and 71.05%, and 89.36% and 88.89%, respectively. SEC16A, age, and AFP were independent risk factors for the occurrence of HBV-LC and HCC. SAA diagnostic cut-off values, sensitivity, and specificity were 26.21 and 31.46, 77.78% and 81.58%, and 87.23% and 97.22%, respectively. The sensitivity and specificity for HBV-HCC early diagnosis were 80.95% and 97.22%, respectively. Pearson correlation analysis showed that AFP level was positively correlated with alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBil), and γ-glutamyltransferase (GGT) with P < 0.01, while the serum SEC16A level was only slightly positively correlated with ALT and AST in the liver cirrhosis group (r = 0.268 and 0.260, respectively, P < 0.05). Conclusion: Plasma SEC16A can be used as a diagnostic marker for hepatitis B-related liver cirrhosis and hepatocellular carcinoma. SEC16A, combined with age and the AFP diagnostic model with SAA, can significantly improve the rate of HBV-LC and HBV-HCC early diagnosis. Additionally, its application is helpful for the diagnosis and differential diagnosis of the progression of HBV-related diseases.

[Precise immunological classification guidance for early initiation of antiviral therapy in patients with chronic HBV infection]

Chronic hepatitis B virus (HBV) infection is a major problem affecting global public health. Appropriate antiviral therapy use can prevent or delay the occurrence of liver cirrhosis and liver cancer. Precise immunological classification can be helpful to formulate personalized therapy and management plans for HBV-infected patients. Antiviral therapy should be started early in those who meet antiviral indications, and nucleos(t)ide analogue therapeutic regimens alone or in combination with pegylated interferon alpha should be optimized according to antiviral therapy response, in order to maximize the realization of virological and serological response, improve clinical cure rate, and enhance long-term prognosis.

[CK7+/CD117- low grade oncocytic tumor of the kidney: a clinicopathological analysis]

Objective: To investigate the clinicopathological, immunohistochemical and molecular characteristics of low grade oncocytic tumors (LOT) of the kidney with CK7+/CD117- staining pattern for enhancing the understanding of renal LOT. Methods: The clinical data, histological morphology and immunophenotypes of seven renal LOT cases diagnosed at the Department of Pathology, the First Affiliated Hospital, Zhejiang University School of Medicine from January 2017 to April 2021 were analyzed. The patients were followed up. Among the seven patients, five underwent high-throughput DNA targeted sequencing, and their molecular characteristics were analyzed. Results: The patients' age ranged 59-82 years, with an average of 70 years. There were 2 males and 5 females. The boundary of the tumor was clear. The tumor cells had homogeneous eosinophilic cytoplasm and round or oval nuclei, with a perinuclear halo. Small basophilic nucleoli were conspicuous (WHO/International Society of Urological Pathology grade 2). In the hypercellular areas, the tumor cells were mainly arranged in dense solid or nest. In the stroma, there were dilated veins, thick-walled arterioles and thick collagen fiber bundles that divided the cells into pseudonodules. In the sparsely cellular area, the tumor cells were arranged in the so-called "tissue culture" fashion. In addition, the stroma contained fresh hemorrhagic foci and lymphoid aggregates. High-throughput sequencing of 5 cases revealed that one case harbored mTOR gene missense mutation and another case harbored TSC1 frameshift mutation. Conclusions: LOT of the kidney is an indolent tumor with an overall good prognosis. Pathologists should not misdiagnose it as renal oncocytoma and chromophobe renal cell carcinoma.

In situ hybridization and RT-PCR detection of Macrobrachium rosenbergii nodavirus in giant freshwater prawn, Macrobrachium rosenbergii (de Man), in Taiwan

Between January and March 2006, suspected outbreaks of white tail disease were observed in post-larvae and juveniles of Macrobrachium rosenbergii in hatcheries and nursery ponds at Kaohsiung and Pingtung Counties in southern Taiwan. Pathognomonic lesions showed the presence of large oval and/or irregular basophilic, cytoplasmic inclusion bodies in the infected muscles and hepatopancreas. Reverse transcriptase polymerase chain reaction (RT-PCR) assay and in situ hybridization (ISH) revealed evidence of M. rosenbergii nodavirus (MrNV) infection but did not detect extra small virus. Phylogenetic analysis indicated that there were very high identities between nucleotide sequences among six strains obtained in this study (99.5-100%), moderate identities with Caribbean and Indian strains (98.2-98.6%), but slightly lower identity with a Chinese strain (95.2%). This is the first confirmation of MrNV in giant freshwater prawns, using an RT-PCR and ISH, in Taiwan.

2-Octyl cyanoacrylate medical adhesive in treatment of a corneal perforation

PURPOSE

To describe a case of successful treatment of a corneal perforation with 2-octyl cyanoacrylate.

METHODS

2-Octyl cyanoacrylate was applied at the slit lamp with topical proparacaine anesthesia to a cornea with an inferior perforation with iris plugging the defect.

RESULTS

After application of 2-octyl cyanoacrylate, the anterior chamber was noted to deepen, and visual acuity improved to 20/200. The glue remained intact for more than 6 weeks and eventually fell out. The underlying cornea healed without scarring, vascularization, or thinning.

CONCLUSION

We have described a case in which 2-octyl cyanoacrylate was used to treat a corneal perforation with excellent results. Further study of this adhesive will be useful in comparing the effectiveness and safety of 2-octyl cyanoacrylate with that of previously studied adhesives.

Retinoic acid-mediated G1 arrest is associated with induction of p27(Kip1) and inhibition of cyclin-dependent kinase 3 in human lung squamous carcinoma CH27 cells

Retinoids are promising agents for the prevention and treatment of several human malignancies including lung cancer. In this study, the effect of retinoic acid (RA) on cell growth and the mechanism of growth modulation were examined in human lung squamous carcinoma CH27 cells. Here we report that RA mediated the dose- and time-dependent growth arrest in G1 phase, accompanied by the up-regulation of p27(Kip1) and the down-regulation of the cyclin-dependent kinase 3 (Cdk3) and p21(CIP1/Waf1) proteins. Furthermore, RA-induced growth arrest of CH27 cells was also associated with increased retinoic acid receptor beta (RARbeta) and reduced c-Myc expression. However, RA had no effect on the levels of cyclins A, D1, D3, E, or H, or on Cdk2, Cdk4, Cdk5, CDk6, Cdk7, p16(Ink4A), p15(Ink4B), p53, or pRb proteins in CH27 cells. Evaluation of the kinase activity of cyclin-Cdk complexes showed that RA increases p27(Kip1) expression in CH27 cells leading to markedly reduced cyclin A/Cdk2 kinase activity and slightly reduced cyclin E/Cdk2 kinase activity, with no effect on cyclin D/Cdk4 and cyclin D/Cdk6 activities. Moreover, coincident with the decrease in kinase activity was a drastic increase in cyclin A-bound p27(Kip1). These results suggest that increases in the levels of p27(Kip1) and its binding to cyclin A, as well as reduction of Cdk3 protein expression, are strong candidates for the cell cycle regulator that prevents the entry into the S phase in RA-treated CH27 cells, with prolongation of G1 phase and inhibition of DNA synthesis.

Cationic lipid structure and formulation considerations for optimal gene transfection of the lung

Enhanced gene transduction to the lung using cationic lipids could be attained through optimization of the structure of the lipids and the formulation of the cationic lipid:plasmid DNA (pDNA) complexes. We have expanded on our earlier observation of the importance of the structural orientation of the cationic lipid headgroup. Through the synthesis of a number of matched pairs of cationic lipids differing only in the configuration of their headgroup, we confirmed that those harboring a T-shape headgroup are more active than their linear counterparts, at least when tested in the lungs of BALB/c mice. Additionally, we demonstrated that not only are the structural considerations of these cationic lipids important, but also their protonation state, the free base being invariably more active than its salt counterpart. The salt forms of cationic lipids bound pDNA with greater avidity, which may have affected their subsequent intracellular dissolution and transit of the pDNA to the nucleus. Inclusion of a number of frequently used solutes in the vehicle severely inhibited the gene transfection activity of the cationic lipids. The selection of neutral co-lipids was also an important factor for overall transfection activity of the formulation, with significant gains in transfection activity realized when diphytanoylphosphatidylethanolamine or dilinoleoylphosphatidylethanolamine were used in lieu of dioleoylphosphatidylethanolamine. Finally, we showed that a transacylation reaction could occur between the cationic lipid and neutral co-lipid which reduced the transfection activity of the complexes. It is the hope that as our understanding of the many factors that influence the activity of these cationic lipid:pDNA complexes improves, formulations with much greater potency can be realized for use in the treatment of pulmonary diseases.

Comparison of two molecular techniques for the detection of avian reoviruses in formalin-fixed, paraffin-embedded chicken tissues

Reverse transcription (RT) in situ polymerase chain reaction (PCR) and in situ hybridization (ISH) techniques were used to detect the sigma c-encoded gene of avian reovirus (ARV) in chicken tissue sections. The advantage of using in situ methods is to make more rapid and accurate diagnosis of ARV infections. The sensitivity of these two techniques were compared. Of the two techniques, the RT in situ PCR test was found to be more sensitive than ISH and provided the rapid, sensitive, and specific detection of ARV infections.

Postmortem diagnosis of hemoglobin SC disease complicated by fat embolism

A case is reported of a previously healthy 52-year-old African American male who presented with acute onset of abdominal pain. Progressive increase in his abdominal symptoms led to an exploratory laparotomy; however, no pathology was discovered. Postoperatively, the patient became hypoxemic which progressed to diffuse infiltrates on chest x-ray, suggestive of adult respiratory distress syndrome. He had a rapidly fatal course. Autopsy showed bone marrow infarction, fat embolism, splenomegaly, and widespread congestion with sickle erythrocytes. Hemoglobin electrophoresis done postmortem showed hemoglobin (Hb) SC disease that was undiagnosed antemortem. To the best of our knowledge, it is unusual for Hb SC to be diagnosed postmortem in adults. This case suggests that sickle cell disorders should be ruled out in patients at risk for hemoglobinopathy in the presence of signs and symptoms compatible with the disease, irrespective of age.

Fine needle aspiration diagnosis of ciliated hepatic foregut cysts: a report of three cases

BACKGROUND

Ciliated hepatic foregut cysts, albeit rare, are important to consider in liver aspirates obtained for evaluation of possible neoplastic disease.

CASES

In three cases, liver fine needle aspirates showed features consistent with ciliated hepatic foregut cysts. Two of these aspirates were obtained to evaluate possible metastatic disease prior to resection of primary tumors, one of the lung and one of the bladder. A third case had radiologic findings suggestive of a cystic neoplasm. The fine needle aspirate material from these cases revealed clusters of tall, columnar cells with basally oriented nuclei and prominent apical terminal plates with cilia. These features are consistent with ciliated hepatic foregut cysts.

CONCLUSION

This entity, although originally described in the late 19th century, to our knowledge has not been reported to occur in fine needle aspirate material and should be included in the differential diagnosis of cystic lesions of the liver.

Isolation and characterization of CAJ1, a novel yeast homolog of dnaJ

A novel member of the Escherichia coli dnaJ family, designated CAJ1, was isolated from a yeast expression library using antiserum against a yeast calmodulin-binding fraction. Although CAJ1 contains neither a Gly-rich region nor a Cys-rich repeat, as are found in other DnaJ relatives, it contains a leucine zipper-like motif.

cDNA cloning of an alternatively spliced isoform of the regulatory subunit of Ca2+/calmodulin-dependent protein phosphatase (calcineurin B alpha 2)

A cDNA encoding the regulatory subunit of Ca2+/calmodulin-dependent protein phosphatase, calcineurin B (CNB), was isolated from a rat testis cDNA library. It differs from the cDNA obtained from a rat brain cDNA library by an addition of 138 base pairs in the coding region. The codon of the clone from a testis library corresponding to the initiation codon of the clone from a brain library is not ATG but AAG, 5'-noncoding regions of these cDNAs are also different. The addition in the coding region results in the gain of 46 amino acids at the N-terminus. These findings suggest that two distinct isoforms of CNB alpha are derived from the same gene through a process involving alternative utilization of two promoters. We designate the brain type isoform as CNB alpha 1 and the longer isoform as CNB alpha 2. Northern blot analysis and reverse transcriptase-polymerase chain reaction (RT-PCR) followed by Southern blot analysis suggest that CNB alpha 2 is specifically expressed in the testis, and its expression is developmentally regulated.

IGF-1 receptor levels and the proliferation of young and senescent human fibroblasts

We have investigated the role of the IGF-1 receptor in the proliferation of young and senescent human diploid fibroblasts. Using WI-38 cells, we have established the following: 1) both young and senescent cells have IGF-1 receptors, which can be autophosphorylated by IGF-1, the intensity of the autophosphorylation being roughly the same in both types of cells; 2) the levels of IGF-1 receptor mRNA are also similar in young and senescent cells; 3) both young and senescent cells have an absolute requirement for the IGF-1 receptor in order to be stimulated by either serum or SV40, respectively; 4) despite these similarities, young cells respond to IGF-1 (in combination with other growth factors) with DNA synthesis and mitosis, and senescent cells do not. We conclude that, although the IGF-1 receptor is still needed by senescent cells for a growth response to SV40, it is not, by itself, the determinant of senescence, at least in WI-38 cells.

FKBP12-FK506 complex inhibits phosphatase activity of two mammalian isoforms of calcineurin irrespective of their substrates or activation mechanisms

The interaction of calcineurin (Ca2+/calmodulin-dependent protein phosphatase) with the potent immunosuppressive agent FK506 and its 12 kDa isoform binding protein (FKBP12) was investigated. The FKBP12-FK506 complex inhibited the Ca2+/calmodulin-stimulated phosphatase activity of each of two calcineurin isoforms, which contain either the catalytic subunit A alpha or A beta (calcineurin A alpha or A beta) of bovine calcineurin. Calcineurin phosphatase activity was inhibited by the FKBP12-FK506 complex irrespective of the substrate or the enzyme activation mechanism. FK506 and FKBP-12 inhibited calcineurin in a concentration-dependent manner, and complete inhibition of the phosphatase activity appeared to require a molar excess of FKBP12-FK506 complex. Immunochemical measurements revealed tissue differences in the concentration of calcineurin, which may be of importance to the selectivity for immunosuppression of all of the biological effects. Direct binding studies with [3H]dihydro-FK506 suggest that the ratio of FKBP12-FK506 complex to calcineurin in vivo when IL2 production is inhibited is well correlated with the ratio when calcineurin phosphatase activity is inhibited in vitro. These results suggest that calcineurin is a relevant cellular target of FK506 when bound to FKBP-12.

Relevance of enantiomeric separations in environmental science

A significant number of all organic chemicals that are released into the environment are racemic mixtures. Most environmental regulations and scientific environmental studies treat racemic mixtures as though they were single, pure compounds. This can lead to incorrect toxicological, distribution, degradation and other data. A series of new enantioselective chromatographic techniques have been developed that allow the facile separation and quantitation of chiral compounds of environmental importance. Nineteen racemic compounds that have been or currently are being released to the environment are resolved. These include: rodenticides--Warfarin, Coumachlor and Coumafuryl; insecticides--Crufomate, Bulan, Fonofos, Mitotane; insect repellent--Ethohexadiol; herbicides and fungicides--Ancymidol, Silvex, Napropamide, phenyl mercuric lactate, 2-[3-chlorophenoxy]propionamide, and 2-chloropropionic acid; and halocarbons-1,2-dichloropropane, 2-bromo-1-chloropropane, 1,2-dibromo-3-chloropropane, 2,3-dichlorobutane and alpha-1,2,3,4,5,6-hexachlorocyclohexane. Several examples are given to illustrate the importance of enantioselective measurements of these and other compounds. Choosing the proper chromatographic technique and chiral stationary phase based on analyte structure is also discussed.

Molecular cloning and characterization of the promoter region of the calcineurin A alpha gene

The 5'-flanking region of the calcineurin A alpha gene was isolated from a rat genomic library. It lacked TATA and CAAT boxes but contained G+C-rich regions, and was demonstrated to function as a strong promoter in neuronal cell lines (NG108-15 mouse neuroblastoma x rat glioma hybrid cells or N1E115 mouse neuroblastoma cells), but not in nonneuronal cell lines (C6 rat glioma or L-M mouse fibroblastoid cells) in a transient chloramphenicol acetyltransferase expression assay. Deletion analysis of the 5'-flanking region revealed that the core promoter region, as well as the sequence critical for cell-type-specific-promoter function, reside within the fragment -107 to +157 with respect to the major transcription initiation site.

A cryptopromoter is activated in the proliferating cell nuclear antigen gene of growth arrested cells

We have examined the regulation of the proliferating cell nuclear antigen gene (PCNA) in a hamster fibroblast cell line (tk-ts13) which is temperature sensitive for growth. These tk-ts13 cells, at the restrictive temperature, are growth arrested in the G1 phase of the cell cycle. The cells were stably transfected with a full length human PCNA gene, and the resulting cell lines (K525 cells) were analyzed. We find that, in growth arrested K525 cells, a cryptopromoter is activated in the transfected human PCNA gene. The cryptopromoter resides in intron 4 which is necessary for proper regulation of the PCNA gene. Removal of this intron leads to increased expression of PCNA in cells which have entered the G0 state. An Alu sequence residing in intron 4 is implicated as the promoter element which is active during growth arrest.

Distinct cellular expression of calcineurin A alpha and A beta in rat brain

Specific polyclonal antibodies that distinguish the two distinct isoforms of the catalytic subunit of calmodulin-dependent protein phosphatase, calcineurin A alpha and A beta, were prepared, and the distribution of calcineurin A alpha and A beta in rat brain was studied using immunochemical and immunocytochemical techniques. Immunochemical measurement revealed that the regional distributions of the two isoforms differed and that A alpha was more abundant than A beta in the rat brain. The subcellular distribution patterns of both isoforms were similar. Both isoforms were highly enriched in cytosolic fractions, including the synaptosomal cytosol. Immunocytochemical analysis revealed that both A alpha and A beta immunoreactivities differed in regional and cellular localizations. These different patterns of expression suggest that the two isoforms of calcineurin A may each have specific functions in modulating neuronal activity in particular cell types.

cDNA cloning of a calcineurin B homolog in Saccharomyces cerevisiae

We have isolated a cDNA clone encoding a homolog of mammalian calcineurin B (the regulatory subunit of calmodulin-dependent protein phosphatase) by screening a cDNA expression library of Saccharomyces cerevisiae with antiserum against bovine calcineurin B. The yeast calcineurin B homolog (YCNB) is composed of 175 amino acids with a calculated molecular mass of 19,639 daltons and contains four putative Ca(2+)-binding domains. The amino-acid alignment of YCNB with human calcineurin B demonstrates 53% sequence identity and 82% homology. Southern blot analysis indicates that the gene for YCNB is a single-copy gene. Thus, yeast calmodulin-dependent protein phosphatase apparently has a heterodimeric structure similar to that of the enzyme in mammalians.

cDNA cloning of a novel testis-specific calcineurin B-like protein

A cDNA clone encoding a novel calcineurin B-like protein (CBLP) was isolated from a rat testis cDNA library by cross-hybridization with a calcineurin B cDNA probe. CBLP is composed of 176 amino acids and contains four putative Ca(2+)-binding domains. The overall predicted amino acid sequence homology between CBLP and calcineurin B is 82%. Northern blots showed that transcripts for CBLP are specifically and highly expressed in the testis.

Senescent human fibroblasts have a post-transcriptional block in the expression of the proliferating cell nuclear antigen gene

The product of the proliferating cell nuclear antigen (PCNA) gene is the co-factor of DNA polymerase delta, which is required for cellular and viral DNA replication. Its steady-state mRNA levels are growth-regulated in young human diploid fibroblasts (HDF) as well as in many other cell types. In senescent HDF, PCNA mRNA is not detectable. However, the PCNA gene is transcribed in senescent HDF as efficiently as in young cells. Furthermore, PCNA hnRNA is easily detectable by reverse transcriptase-polymerase chain reaction in both senescent and young HDF, and the levels are essentially similar. These results indicate that in senescent HDF which are incapable of synthesizing cellular DNA, one of the genes coding for a protein of the DNA-synthesizing apparatus is still transcribed, but the product fails to be processed into mature mRNA.

Characterization of an enhancer-like structure in the promoter region of the proliferating cell nuclear antigen (PCNA) gene

The steady-state mRNA levels of the proliferating cell nuclear antigen (PCNA) gene depend on the length of its promoter. A promoter extending from the HpaII restriction site at -210 from the cap site to the cap site itself is very active, while a -45 promoter (AatII restriction site) is very weak. We now show that the sequences between -73 and -45 of the human PCNA promoter contain an enhancer-like sequence that markedly increases the levels of PCNA mRNA. This sequence has characteristics of an enhancer, having an enhancing function also when placed away from the native position in the 5' flanking sequence. The increase in mRNA levels that occurs after serum stimulation, however, is independent of the enhancer. Synthetic promoters were also constructed containing mutations in the -73 to -45 sequence and these mutants completely lost their ability to drive the transcription of a heterologous cDNA. Nuclear proteins were shown to bind to this sequence, both by gel shift and by methylation interference analysis. We conclude that the levels of PCNA mRNA are controlled, in part, by a structure located in the 5' flanking sequence of the gene, but that this enhancer-like structure does not play a role in the serum regulation of the mRNA levels.

A new growth-regulated complementary DNA with the sequence of a putative trans-activating factor

A new complementary DNA (cDNA) clone has been isolated by differential screening of a cDNA library. The cognate RNA of this clone, called SC1, is growth regulated in human, mouse, and hamster cell lines. Its kinetics of growth regulation (time of increase in mRNA levels, sensitivity to cycloheximide, behavior in G1-specific temperature-sensitive mutants) classify the SC1 gene as a late growth-regulated gene, like the histone genes and the genes coding for the proteins of the DNA synthesis apparatus. By run-on assay, there is a modest increase in transcriptional rates after serum stimulation, which is not sufficient to explain the sharp increase in mRNA levels. The SC1 gene localizes to human chromosome 6p21-22. In bacteria, the SC1 cDNA clone makes a protein of Mr 39,000, in agreement with the putative reading frame. The amino acid sequence derived from the cDNA sequence indicates a previously unknown gene with a domain strongly suggestive of a trans-activating domain. The SC1 gene can be considered as coding for a possible new trans-activating factor that could play an important role in the transcription of genes required for the later stages of cell cycle progression.

The human fibroblast adenine nucleotide translocator gene. Molecular cloning and sequence

The human adenine nucleotide translocator multigene family consists of three transcribed genes and at least seven pseudogenes. We report the cloning and sequencing of the gene expressed in human fibroblasts. Like the other two transcribed genes, it has four exons. The 5'-flanking region of the fibroblast translocase gene contains a functional promoter. The promoter has a TATA motif beginning 30 base pairs upstream of the transcription initiation site and five potential SP1 binding sites, but lacks a canonical CCAAT box immediately upstream of the TATA sequence. Differences among the sequence motifs of the 5'-flanking region of the three human translocase genes could account for differences in their cell type-specific and proliferation-associated expression.

Transcriptional and posttranscriptional regulation of the proliferating cell nuclear antigen gene

The steady-state mRNA levels of the proliferating cell nuclear antigen (PCNA) gene are growth regulated. In a previous paper (L. Ottavio, C.-D. Chang, M. G. Rizzo, S. Travali, C. Casadevall, and R. Baserga, Mol. Cell. Biol. 10:303-309, 1990), we reported that introns (especially intron 4) participate in growth regulation of the PCNA gene. We have now investigated the role of the 5'-flanking sequence of the human PCNA gene stably transfected into BALB/c 3T3 cells. Promoters of different lengths (from -2856 to -45 upstream of the cap site) were tested. All promoters except the AatII promoter (-45), including a short HpaII promoter (-210), were sufficient for a response to serum, platelet-derived growth factor, and to a lesser extent epidermal growth factor. No construct responded to insulin or platelet-poor plasma. The AatII promoter had little detectable activity. Transcriptional activity was also determined in BALB/c 3T3 cells carrying various constructs of the human PCNA gene by two methods: run-on transcription and reverse transcription-polymerase chain reaction (the latter measuring the heterogeneous nuclear RNA [hnRNA] steady-state levels). There was very little difference in the rate of transcription of the PCNA gene between G0 cells and serum-stimulated cells, although the levels of hnRNA were much higher after stimulation. In G0 cells carrying a human PCNA gene without introns 4 and 5, both transcription rate and hnRNA levels were high. Together with data on the mRNA half-life, these results suggest a posttranscriptional component in the regulation of PCNA mRNA levels after serum stimulation but a transcriptional regulation by intron 4.

The promoter of the proliferating cell nuclear antigen (PCNA) gene is active in serum-derived cells

mRNA levels for the Proliferating Cell Nuclear Antigen (PCNA) gene are growth regulated. PCNA promoters of different lengths were used to drive a linked reporter, the cDNA for human thymidine kinase (TK). After transfection into TK ts13 cells, stable cell lines were obtained. Regardless of promoter length, in all cell lines the levels of TK mRNA were roughly similar in serum-deprived and serum stimulated cells, confirming, by an independent method, that the growth regulation of PCNA mRNA levels doe not depend on the 5' flanking sequence of the PCNA gene.

The promoter of the human proliferating cell nuclear antigen (PCNA) gene is bidirectional

The proliferating cell nuclear antigen (PCNA) gene codes for a protein that is necessary for cellular DNA synthesis and cell cycle progression. A functional promoter has been identified in the 5' flanking region of the human PCNA gene. An abbreviated promoter (from the capsite to the PvuII restriction site at -395) was found to be equally efficient in directing transcription from a linked reporter, whether placed in the correct or reverse orientation in respect to the coding sequence. The reporter used was a cDNA of human thymidine kinase (TK), and the bidirectionality of the promoter was demonstrated by its ability to confer the TK+ phenotype to TK- ts 13 cells and by the amount of specific message in RNA blots. The PvuII promoter placed between two coding sequences (the TK cDNA and the bacterial gene for neoresistance) is capable of driving transcription simultaneously in both directions. Finally, in blots of RNA from human cells, two transcripts could be detected that hybridized to a sense riboprobe from the 5' flanking region of the human PCNA gene. We conclude that the locus for the human PCNA gene contains a bidirectional promoter producing diverging transcripts.

Polar-liquid, derivatized cyclodextrin stationary phases for the capillary gas chromatography separation of enantiomers

A new class of hydrophilic, relatively polar liquid, cyclodextrin (CD) derivatives have been used as highly selective chiral stationary phases (CSPs) for capillary gas chromatography (GC). Several possible requirements for liquidity in CD derivatives are discussed. O-(S)-2-Hydroxypropyl derivatives of alpha-, beta-, and gamma-cyclodextrins were synthesized, exclusively characterized, permethylated, and evaluated for enantioselectivity. Seventy pairs of enantiomers were resolved. They represent a wide variety of structural types and classes of compounds including chiral alkyl amines, amino alcohols, epoxides, pyrans, furans, sugars, diols, esters, ketones, bicyclic compounds, alcohols, and so on. Many of these compounds were not aromatic and cannot be resolved on any known liquid chromatographic CSP. Often, these enantiomers had far less functionality than required for LC separation. General properties of these CSPs as well as possible insights into the separation mechanism are discussed.

A human ADP/ATP translocase gene has seven pseudogenes and localizes to chromosome X

There are at least three transcriptionally active human ADP/ATP translocase genes. We have isolated seven ADP/ATP translocase pseudogenes from recombinant human genomic libraries. Each pseudogene sequence had more than 85% identity with the sequence of the human ADP/ATP translocase cDNA derived from fibroblast mRNA, but each had mutations that precluded synthesis of a functional protein. Using an intron probe derived from a partial clone of the human fibroblast ADP/ATP translocase gene, we localized the gene to chromosome Xq13----Xq25-26. The gene encoding the skeletal muscle translocase has previously been shown to be on chromosome 4. Therefore, the human ADP/ATP translocase genes are members of a multigene family that includes pseudogenes and has been dispersed to at least two chromosomes.

Importance of introns in the growth regulation of mRNA levels of the proliferating cell nuclear antigen gene

The steady-state mRNA levels of the proliferating cell nuclear antigen (PCNA) gene are growth regulated. We have begun to identify the elements in the human PCNA gene that participate in its growth regulation by transfecting appropriate constructs in BALB/c3T3 cells. The results can be summarized as follows. (i) The 400 base pairs of the 5'-flanking sequence of the human PCNA gene upstream of the preferred cap site are sufficient for directing expression of a heterologous cDNA (S. Travali, D.-H. Ku, M. G. Rizzo, L. Ottavio, R. Baserga, and B. Calabretta, J. Biol. Chem. 264:7466-7472, 1989). (ii) Intron 4 is necessary for the proper regulation of PCNA mRNA levels in G0 cells. Removal of intron 4 leads to abnormally high levels of PCNA mRNA in serum-deprived cells, although the shortened PCNA gene with its own promoter is still responsive to serum stimulation. (iii) The presence of introns also increases the steady-state levels of PCNA mRNA in proliferating cells. These results are especially interesting for two reasons: (i) because of the extensive sequence similarities among introns and between introns and exons of the human PCNA gene, and (ii) because, usually, the presence of introns leads to increased expression, whereas in this case, removal of intron 4 caused an increase in mRNA levels, and this occurred only in quiescent cells.

Temporary complementation of temperature-sensitive mutants of the cell cycle by transfection with a wild-type or a mutant cDNA of ADP/ATP translocase

A number of cell-cycle-specific temperature-sensitive (ts) mutants have been isolated from animal cells, especially Syrian hamster cells. These ts mutants, like cell cycle ts mutants of yeast, can be complemented by specific genes, some of which have been molecularly cloned. We have isolated a cDNA clone that complements TK-ts13 cells, but only temporarily. This clone, called B1, differs from a previously isolated clone (Sekiguchi et al.: EMBO Journal 7:1683-1687, 1988) that specifically complements ts13 cells. In addition, B1 also complemented temporarily three other ts mutants of the cell cycle, tsAF8, ts694, and ts550C cells. These mutants have different mutations since, in cell fusion experiments, they complement each other. Sequencing of the B1 cDNA clone revealed that it was a mutant of human ADP/ATP translocase in which some human sequences at the 5' end have been replaced by SV40 sequences. The wild-type translocase was less effective but could still increase the survival time of cell cycle ts mutants at the restrictive temperature. Using the polymerase chain reaction, it was possible to demonstrate that the B1 plasmid is expressed in TK-ts13 cells undergoing temporary complementation.

Isolation of a human sequence which complements a mammalian G1-specific temperature-sensitive mutant of the cell cycle

We have isolated a human genomic sequence which corrects the temperature-sensitive phenotype of the G1-specific cell cycle mutant ts13. Transfection of a thymidine kinase negative (TK-) derivative of ts13 with high molecular weight human DNA from placenta of HeLa cells resulted in the isolation of thermocompetent transformants. These transformants were found to possess discrete Hind III fragments containing human Alu family sequences which were conserved in several independent secondary transformants. A transforming sequence was recovered from a HindIII recombinant bacteriophage library prepared from the DNA of one such secondary transformant. The transforming sequence was isolated as a 12.5 kb Hind III fragment.

Use of adenine nucleotide derivatives to assess the potential of exo-active-site-directed reagents as species- or isozyme-specific enzyme inactivators. 3. Synthesis of adenosine 5'-triphosphate derivatives with N6- or 8-substituents bearing iodoacetyl groups

Several series of N6- or 8-substituted derivatives of adenosine 5'-triphosphate (ATP) were synthesized. N6-(omega-Aminoalkyl) derivatives of adenosine 5'-monophosphate (AMP) were converted into their omega-N-carbobenzyloxy derivatives, and these were converted, via the 2',3'-O-carbonyl derivatives of their 5'-phosphorimidazolidates, into the corresponding ATP derivatives. Hydrogenolytic removal of the carbobenzyloxy groups, followed by iodoacetylation of the omega-amino groups with N-(iodoacetoxy)succinimide, gave N6-R-ATP, where R = (CH2)nNHCOCH2I (n = 2--8) or (CH2)nCON)CH3)(CH2)mN(CH3)CO(CH2)nNHCOCH2I (n = m = 3; n = 3, m = 4; n = 4, m = 3; n = m = 4). Condensation of N6-(omega-aminoalkyl) derivatives of AMP with N-hydroxysuccinimide esters of omega-[N-(carbobenzyloxy)amino] carboxylic acids gave N6-(CH2)nNHCO(CH2)mNH-Cbz derivatives of AMP which, upon conversion to the corresponding derivatives of ATP, followed by removal of the carbobenzyloxy group and iodoacetylation, as described above, gave N6-(CH2)nNHCO(CH2)mNHCOCH2I-ATP derivatives (n = 3, m = 5 or 6; n = 4, m = 5; n = 6, m = 1--6). The same sequence of reactions starting with N6-[omega-(methylamino)alkyl] derivatives of N6-CH3-AMP gave N6-CH3, N6-(CH2)nH(CH3)CO(CH2)mNHCOCH2I derivatives of ATP (n = 4, m = 3, 5 or 6; n = 6, m = 5 or 6). Reaction of alpha, omega-diaminoalkanes with 8-Br-ATP gave 8-NH(CH2)nNH2 derivatives of ATP, which upon iodoacetylation gave 8-NH(CH2)nNHCOCH2I derivatives of ATP (n = 2, 4, 6, or 8). Substrate and inhibitor properties indicated that the ATP derivatives are potential exco-ATP-site-directed inactivators of hexokinases, adenylate kinases, and pyruvate kinases.

Stable isolated symmetrical anhydrides of N alpha-9-fluorenylmethyloxycarbonylamino acids in solid-phase peptide synthesis. Methionine-enkephalin synthesis as an example

The synthesis and isolation of symmetrical anhydrides of N alpha-9-fluorenylmethyloxycarbonyl (Fmoc) amino acids using water soluble carbodiimide is described. These compounds were used in a solid phase peptide synthesis of methionine-enkephalin on a p-benzyloxybenzyl ester polystyrene 1% divinylbenzene resin support. Homogeneous free pentapeptide was obtained in 42% overall yield. The Fmoc amino acid symmetrical anhydrides were stable during prolonged storage (2 years of 0 degrees) and offer advantages over present "Fmoc solid phase" methods which use anhydrides formed in situ.

Solid-phase peptide synthesis of somatostatin using mild base cleavage of N alpha-9-fluorenylmethyloxycarbonylamino acids

Experimental details for the "Fmoc solid phase peptide synthesis" of somatostatin are described. The 9-fluorenylmethyloxycarbonyl group was rapidly and quantitatively cleaved by 55% piperidine in dimethylformamide and monitored (u.v.) manually. For a kinetic study, a centrifugal reactor with a photometric control system and reference cell was used at each stage. The symmetrical anhydride coupling reaction was rapid and either acetic anhydride or fluorescamine termination was incorporated to minimize formation of deletion peptides. Anchor-bond cleavage was effected with trifluoroacetic acid which simultaneously removed all the acid labile tert.-butyl side chain protecting groups. N alpha-9-fluorenylmethyloxycarbonyl peptides may be obtained by omitting the piperidine deprotection step after the last cycle of synthesis. From several syntheses, analytically pure di-S-protected somatostatin 14-peptide was obtained in 55-60% overall yield. The S-protecting groups were removed and the product was purified by gel filtration to give homogeneous dihydrosomatostatin (91%) yield. Oxidation of dihydrosomatostatin with potassium ferricyanide and purification by countercurrent distribution provided analytically pure homogeneous somatostatin.

Preparation and properties of Nalpha-9-fluorenylmethyloxycarbonylamino acids bearing tert.-butyl side chain protection

The preparation is described by several Nalpha-9-fluorenylmethyloxycarbonylamino acids and derivatives bearing tert.-butyl type side-chain protection of amine, carboxyl, guanido, hydroxyl, imidazol, and sulfhydryl functionalities. Physicochemical properties of these compounds have been determined. Cleavage of the Fmoc group by various amines appears to depend on the base strength and steric hindrance. Premature deblocking of Fmoc group by amine on solid support is very slow and may be negligible under the conditions of solid-phase synthesis.

Solid phase synthesis without repetitive acidolysis. Preparation of leucyl-alanyl-glycyl-valine using 9-fluorenylmethyloxycarbonylamino acids

The utility of repetitive nonhydrolytic base cleavage of alpha-amino protective groups in solid phase peptide synthesis is shown by a preparation of the model tetrapeptide leucyl-alanyl-glycyl-valine on a p-benzyloxybenzyl ester polystyrene--1% divinylbenzene resin support. Nalpha-9-Fluorenylmethyloxycarbonyl (Fmoc: Carpino & Han, 1970, 1972) amino acids were coupled by the symmetrical anhydride procedure, followed by Fmoc group cleavage using 50% piperidine in methylene chloride. Quantitative removal of the Fmoc-tetrapeptide from the solid support was effected by treatment with 55% trifluoroacetic acid in methylene chloride. Homogeneous free tetrapeptide was obtained in 87% overall yield. The procedure is proposed to offer advantages over present solid phase methods which use acidolysis for repetitive alpha-amino group deblocking.

Solid-phase peptide synthesis using mild base cleavage of N alpha-fluorenylmethyloxycarbonylamino acids, exemplified by a synthesis of dihydrosomatostatin

N alpha-9-Fluorenylmethyloxycarbonyl (Fmoc) amino acids will be of advantage in solid phase peptide synthesis. The Fmoc-group is quantitatively cleaved by mild base (piperidine). This permits the use of tert-butyl-type side chain blocking and of peptide-to-resin linkage cleavable by mild acidolysis. Side reactions arising from repetitive acid deprotection and final HF cleavage in contemporary solid phase synthesis are avoided. Fully bioactive and homogeneous dihydrosomatostatin was obtained in 53% overall yield.

Analogues of S-adenosylhomocysteine as potential inhibitors of biological transmethylation. Synthesis of analogues with modifications at the 5'-thioether linkage

The synthesis of S-adenosylhomocysteine analogues, in which the 5'-thioether linkage is replaced by an oxygen or nitrogen isostere, has been investigated. These compounds were disigned to be resistant to enzyme-catalyzed hydrolytic cleavage of the 5'-substituent. The amine analogue Id and two amide analogues 20 were prepared via alkylation or acylation of appropriately blocked adenosine derivatives. These new analogues were evaluated as inhibitors of catechol O-methyltransferase and tRNA methylases and found to have poor inhibitory activity.