Myb protein binds to multiple sites in the human T cell lymphotropic virus type 1 long terminal repeat and transactivates LTR-mediated expression

The members of the c-myb proto-oncogene family encode sequence-specific transcriptional activators. In T cells, expression of c-myb and the related B-myb gene is induced following mitogenic stimulation. Using a purified recombinant protein, we report here that the human T cell lymphotropic virus type 1 (HTLV-1) LTR contains six specific binding sites for Myb. We also show that HTLV-1 LTR chloramphenicol acetyl transferase reporter plasmids are specifically transactivated by c-Myb. These data suggest a role for members of the Myb family as a link between transcriptional activation of the HTLV-1 LTR and T cell activation events.

Plasmapheresis. A therapeutic option in the management of heparin-associated thrombocytopenia with thrombosis

Heparin-associated thrombocytopenia with thrombosis (HATT) is an uncommon syndrome that is estimated to occur in 1-5% of patients with heparin-induced thrombocytopenia. Early diagnosis requires careful clinical surveillance, and the management of these patients can be complex. Cessation of heparin therapy and substitution or addition of oral anticoagulants, antiplatelet agents, dextrans, and prostacyclin analogues have been advocated. The authors are aware of only two case reports in the literature that examine the use of plasmapheresis as a therapeutic alternative. The authors report a case of a 53-year-old white man who developed HATT after a single protamine-reversed exposure to heparin. Controlled platelet aggregation studies performed before and after apheresis sessions documented a dramatic response and rapid normalization of platelet number and function in the patient. The authors conclude that plasmapheresis could be a valuable adjunct in the successful management of patients with HATT. When done in conjunction with platelet aggregation studies, an objective measurement of therapeutic efficacy can be achieved.

Improvements in detection of antibody to hepatitis B core antigen by treating specimens with reducing agent in an automated microparticle enzyme immunoassay

A fully automated microparticle enzyme immunoassay (EIA), IMx Core, was developed for the detection of antibody against hepatitis B core antigen (anti-HBc). IMx Core sensitivity was less than 0.5 Paul Ehrlich Institut units per ml and was greater than that of the commercial radioimmunoassay (RIA) or EIA, Corab and Corzyme, respectively. Specimens from blood donors and diagnostic and hospital patients, which included individuals with a variety of infectious and immune diseases, were tested in parallel by the IMx Core and EIA. Overall agreement of 99.1% (4,797 of 4,841) was obtained. Prevalence of anti-HBc tested by IMx Core ranged from 1.2% in volunteer blood donors to 9.1% in hospital laboratories. Discordant specimens reactive by IMx Core but negative by Corzyme or Corab resulted from the increased sensitivity of the IMx Core assay, since other hepatitis B markers were usually present. However, most discordant specimens were positive by the EIA or RIA but negative by IMx Core. No other hepatitis B markers could be detected in these discordants, and after addition of reducing agent, these specimens also became negative by EIA or RIA. In clinical trials, 30% (14 of 47) of volunteer blood donors and 8% (9 of 119) of hospital patients testing repeatedly reactive by the EIA had reduction-sensitive (unspecific) anti-HBc reactivity. The reducing agent, dithiothreitol, was added to each specimen automatically in the IMx assay to eliminate these unspecific reactions without significantly affecting anti-HBc reactivity resulting from hepatitis B virus infection as judged by the correlation with other hepatitis B markers.

The product of the c-ets-1 proto-oncogene and the related Ets2 protein act as transcriptional activators of the long terminal repeat of human T cell leukemia virus HTLV-1

The c-ets-1 proto-oncogene and the related c-ets-2 gene encode related nuclear chromatin-associated proteins which bind DNA in vitro. To investigate the possibility that Ets1 and Ets2 are transcriptional activators, we analyzed the ability of these proteins to trans-activate promoter/enhancer sequences in transient co-transfection experiments. A CAT construct driven by the long terminal repeat of the human T cell leukemia virus, HTLV-1 was found to be trans-activated by both Ets1 and Ets2 in NIH3T3 and HeLa cells. The increased levels of CAT activity were paralleled by increased levels of correctly initiated CAT mRNA. Mutant Ets1 proteins unable to accumulate in the nucleus were found to be inactive. An ets-responsive sequence between positions -117 and -160 of the LTR was identified by analyses of a series of 5' deletion mutants of the HTLV-1 LTR and of dimerized versions of specific motifs of the LTR enhancer region. Using a gel shift binding assay, Ets1 was found to bind specifically to an oligonucleotide corresponding to region -117 to -160. This sequence, which also contributes to Tax1 responsiveness of the HTLV-1 LTR, is characterized by the presence of four repeats of a pentanucleotide sequence of the type CC(T/A)CC. Competition experiments show that integrity of repeats 1 and 4 is important for Ets1 binding. These results show that Ets1 and Ets2 are sequence-specific transcriptional activators. In view of the high level expression of Ets1 in lymphoid cells, Ets1 could be part of the transcription complex which mediates the response to Tax1 and the control of HTLV-1 replication. More generally, Ets1 and Ets2 could regulate transcription of cellular genes.

Familial primary failure of eruption of permanent teeth

A son and his mother presented with features consistent with a diagnosis of primary failure of eruption. The features of this condition are described together with some aspects of treatment. The impact of the condition on vertical facial growth is discussed.

The human cytomegalovirus mtrII colinear region in strain Tanaka is transformation defective

The morphological transforming region II (mtrII) of human cytomegalovirus (HCMV) strain Towne has been localized to a 980-base-pair fragment containing three putative open reading frames (ORFs) of 79, 83, and 34 amino acids (aa). In addition, noncoding DNA sequence elements which have the potential to form stem-loop structures were also observed within mtrII. To determine what elements within HCMV Towne mtrII are important in transformation, colinear regions in other HCMV strains (AD169 and Tanaka) were isolated and a comparison of transforming potential was performed. The results indicated that the 2.2-kilobase colinear region in strain AD169 was transforming, whereas the colinear mtrII region in strain Tanaka showed significantly reduced transforming potential. Analysis of the nucleotide sequence data of these colinear regions revealed the presence of the 79-aa ORF in strains Towne and AD169 and its absence in strain Tanaka. In addition, BglII-digested Towne mtrII, which was cleaved within the 79-aa ORF, was shown to display significantly reduced transforming potential. Since the 83- and 34-aa coding sequences were interrupted in both the transforming AD169 colinear region and the nontransforming Tanaka strains, these ORFs were thought not to be important in transformation. Analysis of the stem-loop structures within each of the mtrII colinear regions did not reveal significant changes among the transforming and nontransforming colinear fragments. Thus, the comparative data indicate an important role for the 79-aa ORF in transformation.

The adenovirus EIIA enhancer. Analysis of regulatory sequences and changes in binding activity of ATF and EIIF following adenovirus infection

Adenovirus EIIA upstream sequences which contain the binding sites for proteins ATF and EIIF act as an enhancer and can be trans-activated by both E1A and SV40 T/t-antigens. Specific mutation of either the ATF or EIIF binding site demonstrates that both act as positive regulators, decreasing transcription greater than 10-fold. Mutation of both the ATF and EIIF binding sites inhibited the EIIA enhancer 200-fold. Analysis of insertion mutations suggests that the spatial alignment of the upstream ATF and EIIF binding sites with respect to the downstream EIIF binding site on the DNA helix is important. Consistent with previous findings, using gel shift analysis we demonstrate that the binding activity of EIIF is increased following wild-type adenovirus infection. In contrast, using identical gel shift conditions, the binding activity of ATF is decreased by viral infection.

trans-activation of RNA polymerase II and III promoters by SV40 small t antigen

A biochemical role for SV40 small t antigen (t) in the viral infectious cycle that would explain the strong conservation of t structure among papovaviruses and its role as a helper of SV40 large T antigen function in the viral transforming process is not understood. Here, we report an intracellular biochemical function of the protein--the capacity to trans-activate selected RNA polymerase II and III-requiring promoters. Since t has failed in the past to bind to DNA and did not stimulate all polymerase II-requiring promoters tested, it likely trans-activates, at least in part, by modifying the activity of selected transcription factors.

Characterization of cellular factors that interact with the human T-cell leukemia virus type I p40x-responsive 21-base-pair sequence

Transcriptional activation of the human T-cell leukemia virus type I (HTLV-I) long terminal repeat (LTR) by viral protein p40x requires a 21-base-pair (bp) sequence which is repeated three times within the LTR. This sequence contains a core octanucleotide (TGACGTCT) which has been attributed to be a cyclic-AMP (cAMP)-responsive element. We demonstrate here that the HTLV-I LTR can be specifically stimulated by cAMP regulators and have identified four proteins in HeLa cells that bind to the HTLV-I 21-bp sequence. We correlated the in vitro binding and transcriptional activity of one of these cellular factors (Mr, 180,000) to the trans-activation of the HTLV-I LTR by p40x. Point mutations were generated within the cAMP octanucleotide of the HTLV-I 21-bp sequence that simultaneously abolished biological responsiveness to trans-activation by p40x and to stimulation by cAMP. We found that these mutations also eliminated the binding of the 180-kilodalton HeLa factor to the HTLV-I 21-bp element. In the absence of a demonstrable DNA-binding property for p40x, we hypothesize that cellular proteins are involved, possibly through signal transduction pathways, in its trans-activation of responsive promoters.

Localization and DNA sequence analysis of the transforming domain (mtrII) of human cytomegalovirus

To define the morphological transforming region II (mtrII) of human cytomegalovirus (HCMV), a series of subclones of the Xba I/BamHI fragment EM was constructed in vitro and tested for focus-forming activity and tumorigenicity. A 980-base-pair subclone of fragment EM was identified, and its nucleotide sequence revealed three small open reading frames (ORFs), encoding 79, 83, and 34 amino acid residues. S1 nuclease analysis of HCMV-infected cells identified several distinct early RNA species within mtrII, two of which (P1 and P2) were of particular interest, since the length of the protected DNA fragments would position the 5' end of the RNAs upstream of the open reading frames. In addition, the 980-base-pair transforming sequence revealed DNA elements capable of forming stem-loop structures. Thus the transforming mtrII domain of HCMV strain Towne contains both small open reading frames that are expressed in lytically infected cells and sequences resembling insertion-like structures that may be involved in transformation.

Carboxyl-terminal mutants of the large tumor antigen of simian virus 40: a role for the early protein late in the lytic cycle

Simian virus 40 (SV40) mutants dl1066 and dl1140 contain deletions within the region encoding the carboxyl terminus of the large tumor (T) antigen. Although these mutations have little effect on the efficiency of viral DNA replication, they decrease the yield of infectious virus particles by 3-4 orders of magnitude [Pipas, J. (1985) J. Virol. 54, 569-575]. Here we show that the level of late RNA is lower by a factor of 5-15 in CV-1P monkey cells infected with these mutants compared to cells infected with wild-type SV40. Consistent with this decrease in RNA, synthesis of late viral structural proteins VP1 and VP3 decreases by a factor of 5-15. In contrast, the synthesis of SV40 agnoprotein decreases by a factor greater than 100. Intercistronic complementation of these mutants with pm1493 and dl121, two SV40 mutants that are defective in agnoprotein but encode wild-type T antigen, results in an increased synthesis of agnoprotein in the infected cells. These results suggest that the carboxyl-terminal portion of T antigen participates in the posttranscriptional regulation of agnoprotein.

72-bp element contains a critical control region for SV40 late expression in Xenopus laevis oocytes

The SV40 late promoter is transcribed at least 10-fold more efficiently than the SV40 early promoter when SV40 DNA is injected into the germinal vesicle of Xenopus laevis oocytes. Late expression in the oocyte is independent of T antigen and does not require DNA replication. To identify DNA sequences required for SV40 late gene expression, 12 mutants spanning nucleotide position (np) 5187 to np 304 were injected into the germinal vesicles of X. laevis oocytes, and RNA was extracted 18 to 24 hr later. S1 nuclease analysis of the 5' ends of SV40 late mRNA revealed that mutations in the origin of replication had no quantitative or qualitative effect on the 5' late start sites. Mutants which deleted the 21-bp repeats did not reduce or alter use of the major RNA initiation site (np 295), but did reduce use of a minor initiation site within the 72-bp repeats. In contrast, deletion of or certain point mutations in the 72-bp repeat decreased initiation from the major late start site. An 85-bp insertion containing a complete set of the 21-bp repeats positioned to the late side of the enhancer elements also decreased initiation from the major late start site. Thus, an element in the 72-bp repeat appears to be the major promoter element for late SV40 transcription in the oocyte.

Identification of p40x-responsive regulatory sequences within the human T-cell leukemia virus type I long terminal repeat

Distinct transcriptional regulatory sequences located within the upstream sequences required for p40x trans-activation of the human T-cell leukemia virus type I (HTLV-I) long terminal repeat (LTR) were chemically synthesized and cloned upstream of the basal HTLV-I LTR promoter. Plasmids containing a single 21-base-pair (bp) repeat were weakly inducible by p40x. The level of trans-activation by p40x was increased when two (30-fold) or three (40-fold) 21-bp repeats were present in the upstream control region. In the mutant containing two 21-bp repeats, the upstream 21-bp repeat could be positioned in either the sense (30-fold) or the antisense (16-fold) orientation. Plasmids containing a 51-bp repeat element, which included a single 21-bp repeat, were induced to levels similar to that obtained with the 21-bp repeat sequence alone. Template DNAs containing a single copy of the HTLV-I sequences between -117 and -160 were stimulated approximately 10-fold by p40x when one copy of the 21-bp element was located downstream.

Translational regulation of SV40 early mRNA defines a new viral protein

SP6-initiated in vitro transcripts, representing the three major classes of early SV40 mRNAs, early-early (EE) and two late-early (LE) transcripts, were assayed by in vitro translation to compare their relative efficiencies for synthesis of the SV40 T antigens. The presence of one or two potential AUG initiator codons in the leader sequences of the LE RNAs inhibits efficient translation from the downstream T-antigen initiator AUG. In vitro translation of the capped form of the shorter SV40 LE RNA resulted in the synthesis of a 2.7-kd protein. In vivo pulse labeling of SV40-infected CV-1 cells demonstrated the accumulation of a peptide of similar size at late times after lytic infection, indicating that it is an authentic viral protein encoded by the early leader sequence of SV40.

Cyclosporine pharmacokinetic profiles in liver, heart, and kidney transplant patients as determined by high-performance liquid chromatography

Cs pharmacokinetic profiles using HPLC have aided in predicting necessary dosage alterations for specific groups of transplant patients. Additional information has been gained by HPLC profiles in nontransplant subjects who are healthy or have a stable disease state. The clinician now knows that liver disease not only impairs Cs elimination but may also have a pronounced effect upon drug absorption. While the cardiac failure patient may have reversible inhibition of Cs clearance, other factors may affect the distribution of the drug to lower dosage requirements. Impaired renal function is not an impediment to Cs elimination, but malabsorption similar to that observed in liver and bone marrow transplant patients may still occasionally complicate therapy. Pharmacokinetic information on Cs must be integrated into the complex care plan of a transplant patient to optimally utilize and monitor this pharmacologic agent.

Spacing between simian virus 40 early transcriptional control sequences is important for regulation of early RNA synthesis and gene expression

We have analyzed the effect of insertion mutants between the simian virus 40 (SV40) 21-base pair (bp) repeats and the early-early (EE) TATA sequence. Insertion of 4, 42, or 90 bp of DNA at the SV40 NcoI site (map position 37) has been analyzed for its effect on expression of the SV40 early gene and positioning of the RNA 5' ends. Insertion of 4 bp reduced SV40 early promoter-dependent chloramphenicol acetyltransferase (CAT) expression by six- to eightfold. Increasing the size of the insertion to 42 or 90 bp resulted in a further drop in early gene expression to basal levels. At the RNA level, the 4-bp insertion reduced EE RNA synthesis approximately 10-fold. No concomitant increase in late-early (LE) RNA synthesis was observed. Insertion of 42 or 90 bp of DNA resulted in a decrease of EE RNA synthesis and a stimulation of LE RNA synthesis. Deletion of the SV40 72-bp repeats from the insertion mutants demonstrated that some, but not all, of the LE RNA depends upon the presence of these sequences. These studies suggest that the ability of RNA polymerase II to utilize the EE (TATA-directed) transcriptional control sequence requires an interaction with the upstream 21-bp repeats or the 72-bp repeats or both. That LE RNA levels in pJI1-in42 CAT and pJI1-in90 CAT were equivalent to the level of EE RNA in pJI1-CAT, yet the level of CAT gene expression was decreased greater than 10-fold, suggests that LE mRNA is under translational control and probably prefers a 5' initiation codon proximal to that of the CAT gene.

Trends in private insurance coverage for mental illness

The authors analyzed data from the U.S. Bureau of Labor Statistics Level of Benefits Surveys for the period 1979-1984 to examine coverage for psychiatric disorders in the private sector. While the overall number of employees with psychiatric benefits has increased, a greater percentage have more restrictions on those benefits. The extent of coverage is wide ranging, but there is little depth and the majority of psychiatric care expenses are not insured. Although the figures do not suggest a dramatic cutback in insurance coverage, the trends toward increased reductions in benefits for all health care threaten the more vulnerable psychiatric benefits.

Stimulation of the adenovirus E2 promoter by simian virus 40 T antigen or E1A occurs by different mechanisms

We have examined the ability of simian virus 40 T antigen to stimulate transcription from the adenovirus E2 promoter. T antigen, produced from a cotransfected plasmid, stimulated chloramphenicol acetyltransferase enzyme and mRNA production from an E2 promoter-chloramphenicol acetyltransferase fusion plasmid (pEC113) in monkey kidney CV-1 cells. The level of stimulation of E2 transcription by simian virus 40 T antigen was equal to that observed in cotransfections of pEC113 and the adenovirus E1A gene product. Deletion mutations from the 5' end of the E2 promoter were examined for their ability to express basal, T-antigen, or E1A trans-activated promoter activity. In each case, deletion of upstream promoter sequences to -70 base pairs reduced chloramphenicol acetyltransferase expression to approximately 30% of the level observed with the intact E2 promoter. Deletion to -59 base pairs resulted in chloramphenicol acetyltransferase expression that was 3 to 5% of that observed with the intact E2 promoter. At saturating levels of the stimulatory proteins, the chloramphenicol acetyltransferase levels obtained in response to T antigen and adenovirus E1A were additive. COS-1 cells, which are derived from CV-1 cells and constitutively express simian virus 40 T antigen, do not support E2 promoter trans activation by T antigen. E1A trans activation of the E2 promoter is efficient in COS-1 cells. These results suggest that although promoter sequence requirements are similar, T antigen and E1A trans activate the E2 promoter by different mechanisms.

Intraperitoneal recombinant alpha 2-interferon for 'salvage' immunotherapy in persistent epithelial ovarian cancer

Fourteen patients with epithelial ovarian cancer were treated with intraperitoneal (i.p.) administration of alpha-recombinant interferon (rIFN-alpha 2) after documentation of persistent disease at second-look laparotomy and combination chemotherapy. After therapy, 11 patients had a surgical re-evaluation which confirmed 4 complete responses (36%), 1 partial response (9%), and disease progression in 6 (55%). Five of 7 patients (71%) with minimal residual disease (MRD, i.e. less than 5 mm) had a surgically-documented response, whereas there was none in the 4 patients whose tumors were greater than or equal to 5 mm. Fever greater than or equal to 38 degrees C was seen in 58%, greater than or equal to 39.0 degrees C in 18%; nausea and vomiting in 37%, and abdominal pain in 22%. There was no consistent alteration in peripheral WBC's during treatment, while i.p. monocytes and lymphocytes showed a significant boost on day 1 after each dose of rIFN-alpha 2. Natural killer (NK) lymphocyte cytotoxicity was elevated in the i.p. cavity fluid obtained from most patients on day 1 after treatment, while blood NK values showed considerable variability. Pharmacokinetic studies showed i.p. levels of rIFN-alpha 2 were 30-1000 times blood levels. I.p. rIFN-alpha 2 may act by increasing concentrations of drug and augmenting regional host cells in patients with MRD ovarian cancer.

Interaction between two transcriptional control sequences required for tumor-antigen-mediated simian virus 40 late gene expression

Transcriptional control signals required for tumor (T)-antigen trans-activation of the simian virus 40 (SV40) late promoter include T-antigen binding sites I and II and the SV40 72-base-pair (bp) repeats. We have used in vivo competition studies to examine how these signals function in relationship to one another. In vivo competition with recombinant plasmids containing the entire SV40 late regulatory region and promoter sequences [map position (mp) 5171-272] results in quantitative removal of limiting trans-acting factor(s) required for late gene expression in COS-1 cells. Deletion of either the T-antigen binding sites (mp 5171-5243) or the 72-bp tandem repeat (mp 128-272) from the competitor plasmid results in markedly less efficient binding of the trans-acting factor, as judged by the loss of competition. Cotransfection of two separate plasmids, one containing the T-antigen binding sites I and II and the other containing the 72-bp repeats, fails to compete for the trans-acting factors. Insertion of increasing lengths of DNA sequences between the T-antigen binding sites and the enhancer sequences also dramatically reduces the efficiency of competition. These results suggest that efficient binding of trans-acting factors requires the presence, in cis, of at least two SV40 regulatory domains. Our studies further suggest that the distance separating these two transcriptional signals is important.

Intraperitoneal recombinant alpha-interferon for "salvage" immunotherapy in stage III epithelial ovarian cancer: a Gynecologic Oncology Group Study

Fourteen patients with persistent epithelial ovarian cancer documented at second look laparotomy after combination chemotherapy were treated with 146 cycles of alpha-recombinant interferon (rIFN-alpha 2) administered i.p. The initial dose was 5 X 10(6) units which was escalated weekly to 50 X 10(6) units over 4 weeks and then continued weekly for a total of 16 weeks. Eleven patients underwent surgical reevaluation after therapy which confirmed four pathological complete responses (36%), one partial response (9%), and disease progression in six patients (55%). Five of seven patients (71%) with residual tumor less than 5 mm had a surgically documented response, whereas there was no response in the four patients whose tumors were greater than or equal to 5 mm. Three patients were evaluable for clinical response only: one patient who refused surgery had a complete clinical response with total resolution of ascites; one had stable disease; and one had disease progression. Fever greater than or equal to 38 degrees C was seen in 58%, fever greater than or equal to 39.0 degrees C was seen in 18%, vomiting in 37%, abdominal pain was reported in 22%, and one patient had infectious peritonitis. Peripheral white blood cell counts and i.p. washings were obtained pretreatment and on days 1, 3, and 7 after treatment. While there was no consistent alteration in peripheral white blood cell counts, the numbers of i.p. monocytes and lymphocytes showed a significant boost on day 1 after each dose of rIFN-alpha 2. Natural killer lymphocyte cytotoxicity was elevated in the i.p. cavity fluid obtained from most patients on day 1 after treatment, while blood natural killer lymphocyte cytotoxicity values showed considerable variability. Pharmacokinetic studies show that i.p. levels of rIFN-alpha 2 were 30-1000 times blood levels. rIFN-alpha 2 i.p. may act by increasing concentrations of drug and augmenting regional host cells in patients with minimal residual ovarian cancer.

Recombinant alpha-2 interferon in the treatment of hairy cell leukemia

We treated 14 patients with hairy cell leukemia, 13 of whom had progressive disease, with recombinant alpha-2 interferon administered sc at 2 X 10(6) units/m2, three times per week. Thirteen patients were evaluable for response. All evaluable patients responded within 6-8 weeks. After a minimal treatment duration of 6 months and a maximal of 12 months, three patients have achieved complete response and ten have achieved partial response. With a median treatment duration of 10 months, the responding patients' hematologic parameters are continuing to improve, and no responding patients have relapsed. This outpatient self-administered regimen is well-tolerated, with mild fever, myalgias, and headache usually resolving within 2 months. Although the optimal regimen and the mechanism of action are unknown, recombinant alpha-2 interferon may be the treatment of choice for patients whose disease progresses after splenectomy or who are not surgical candidates.

Utilization and coverage of mental health services in health maintenance organizations

Health maintenance organizations (HMOs) generally have very limited coverage of mental health care and have been charged with shortchanging chronic patients in the interests of economy. The authors analyzed 1979-1980 coverage and utilization data from 53 federally qualified HMOs. They found that while coverage is limited and very similar across the spectrum of HMOs, utilization rates vary greatly and do not correlate with extent of coverage. They suggest that management decisions may be critical in determining access to and use of mental health benefits in HMOs.

Structure of proteins with single-site mutations: a minimum perturbation approach

A large number of mutant proteins with single amino acid substitutions are now being produced. The ability to predict the structural changes expected from such mutations would aid greatly in the efficient utilization of the mutagenic techniques and in the interpretation of the changes in stability and function that result. A minimum perturbation approach is suggested as a first step in such structural predictions and is tested by application to a recently isolated variant of the hemagglutinin glycoprotein. The agreement between the predicted structure and that inferred from the x-ray refinement is encouraging and provides support for the proposed modeling procedure.

Reductions in coverage for mental and nervous illness in the Federal Employees Health Benefits Program, 1980-1984

After nearly 15 years of nondiscriminatory coverage, the largest plan in the Federal Employees Health Benefits Program cut its coverage of care for mental illness disproportionately to coverage for other health care in 1981 and 1982. "Catastrophic" coverage for inpatient mental illness care was introduced by many of the plans in 1984. The authors review the reductions in coverage from economic and clinical perspectives, highlighting the impact of the disparity between the coverage for mental illness and other medical conditions. The model of catastrophic protection for treatment of mental illness set forth in the Federal Employees Health Benefits Program does not bode well for the patient and family who must cope with such a financial contingency.

Nitrendipine: effects on vascular responses and myocardial binding

We have further defined the binding characteristics of [3H]nitrendipine to myocardial microsomal membranes of cats, dogs, rats, and rabbits and to canine coronary vasculature (1.5-3.0 mm OD), and we have studied nitrendipine's effect on contractile responses in isolated feline cardiac muscle and canine coronary arteries. [3H]nitrendipine binding is rapid, saturable, and reversible in all four species and in all of these tissues. Feline myocardium has a single binding site with a dissociation constant (KD) of 1.94 nM. Canine myocardium may have two classes of binding sites, with the high-affinity site having a KD of 0.17 nM. Nitrendipine depresses contractility in isolated feline cardiac muscle and canine coronary arteries in a dose-dependent manner [half-maximal dose (ED50) 0.20 microM in isolated feline cardiac muscle and 1.6-6.3 nM for potential dependent contractile responses in isolated canine coronary arteries] and severely blunts the contractile response to increases in extracellular calcium concentration in isolated feline papillary muscles. In contrast to verapamil and D 600, nitrendipine does not prevent the treppe phenomenon. In isolated feline cardiac muscle and large canine coronary arteries, the minimal nitrendipine concentration required for specific binding and for depression of contractile responses is similar. However, only in large canine coronary arteries is the ED50 for nifedipine's depression of contractility similar to the KD for [3H]nitrendipine binding in the respective tissue.

Internal resorption complicating orthodontic tooth movement

A case report is presented of an orthodontic patient who suffered internal resorption and a consequent 'pink spot' affecting a maxillary central incisor. Its management is outlined. The aetiology and possible cellular events responsible are discussed.

Stimulation of simian virus 40 late gene expression by simian virus 40 tumor antigen

The early simian virus 40 (SV40) gene product, large tumor (T) antigen, is responsible for the initiation of viral DNA replication and the autoregulation of early gene expression through direct protein-DNA interactions. We investigated the role of T antigen in late viral gene expression, independent of its function in amplifying templates through DNA replication. SV40 DNA was transfected into BSC-1 and COS-1 cells and cultured in the presence of inhibitors of DNA replication. Electrophoretic immunoblot analysis indicated that both the onset and the extent of SV40 late gene expression is increased in COS-1 cells, which constitutively express SV40 T antigen. Blot hybridization analysis of poly(A)-selected RNA demonstrated that the level of synthesis of the major late structural protein VP-1 in COS-1 cells was due to increased transcription. Similar results were obtained when plasmids that contain the SV40 late gene but lack both the origin for viral DNA replication and the early gene coding region were transfected onto COS-1 cells. Using lines of SV40-transformed monkey kidney cells that express altered T antigens, we found that enhanced expression of the late gene product is correlated with the ability of T antigen to bind SV40 DNA. These results indicate that large T antigen plays a role in the stimulation of late viral gene expression.

Simian virus 40 major late promoter: an upstream DNA sequence required for efficient in vitro transcription

We have previously identified an 11-base DNA sequence, 5'-G-G-T-A-C-C-T-A-A-C-C-3' (simian virus 40 [SV40] map position 294 to 304), which is important in the control of SV40 late RNA expression in vitro and in vivo (Brady et al., Cell 31:625-633, 1982). We report here the identification of another domain of the SV40 late promoter. A series of mutants with deletions extending from SV40 map position 0 to 300 was prepared by nuclease BAL 31 treatment. The cloned templates were then analyzed for efficiency and accuracy of late SV40 RNA expression in the Manley in vitro transcription system. Our studies showed that, in addition to the promoter domain near map position 300, there are essential DNA sequences between nucleotide positions 74 and 95 that are required for efficient expression of late SV40 RNA. Included in this SV40 DNA sequence were two of the six GGGCGG SV40 repeat sequences and an 11-nucleotide segment which showed strong homology with the upstream sequences required for the efficient in vitro and in vivo expression of the histone H2A gene. This upstream promoter sequence supported transcription with the same efficiency even when it was moved 72 nucleotides closer to the major late cap site. In vitro promoter competition analysis demonstrated that the upstream promoter sequence, independent of the 294 to 304 promoter element, is capable of binding polymerase-transcription factors required for SV40 late gene transcription. Finally, we show that DNA sequences which control the specificity of RNA initiation at nucleotide 325 lie downstream of map position 294.

Differences in myocardial alpha- and beta-adrenergic receptor numbers in different species

In the present study, we tested the hypotheses that 1) different species have different myocardial adrenergic receptor numbers and 2) selected "slow-channel" calcium antagonists compete with alpha-adrenergic antagonists for binding to varying degrees in different species. The data obtained in the present study demonstrate that there is a markedly decreased number of alpha 1-adrenergic and increased number of beta-adrenergic receptors in canine compared with rabbit and rat myocardium. The differences in adrenergic receptor numbers exist without major differences in alpha 1-adrenergic receptor affinity in the species studied. There was no significant difference in left ventricular or plasma catecholamine content between the rat and dog. Selected slow-channel calcium antagonists compete for alpha 1-adrenergic receptor binding in rabbit, rat, and canine myocardium. However, only in rabbit myocardium does verapamil antagonize alpha 1-adrenergic receptor binding at moderate concentrations, whereas verapamil in canine and rat myocardium and 1) 600 in all three species antagonize alpha 1-adrenergic receptor binding only at relatively high concentrations. Nifedipine, a dihydropyridine-type slow-channel calcium antagonist, had no effect on prazosin binding to rat, rabbit, and dog myocardial membranes.

Site-specific base substitution and deletion mutations that enhance or suppress transcription of the SV40 major late RNA

Transcriptional analysis of SV40 late promoter mutants indicates that the DNA sequence 5'-GGTACCTAACC-3' (map positions 294-304) is important in the control of SV40 late RNA expression. C to T base substitutions at map positions 298, 299 and 304 increased initiation of late RNA synthesis at map position 325 five to ten fold. G to A base substitutions at map positions 294 and 295 decreased RNA initiation by a factor of 2 to 3. Deletion of nucleotides 295-298 reduced RNA initiation by a factor of 4 to 5. S1 analysis of in vivo RNA, isolated 24-36 hr after infection, demonstrated that the four base deletion not only decreased RNA initiation at nucleotide 325, but also increased RNA initiation at three alternate sites located approximately 125 nucleotides upstream from the major late RNA initiation site.

Angiosarcoma of the liver: a signal lesion of vinyl chloride exposure

Vinyl chloride (VCM) induced angiosarcoma of the liver (ASL) is a rare vascular tumor which might be associated with a wide range of disease states. The possibility that this tumor might be a signal lesion is supported by mortality studies suggesting that cancers of the digestive, respiratory, neurological and lymphatic systems have occurred more often than expected in VCM workers. There is also evidence that certain non-neoplastic disorders, such as pneumoconiosis and excess fetal deaths, may be associated with this chemical. It has been suggested that a gradual increase in the incidence of ASL might have occurred in recent years. This could be a reflection of the long latency period and/or the increased recognition of this entity. Several cases of ASL have occurred in people living in the vicinity of VCM plants. This raises the possibility that low-level exposure to this chemical over a long period might induce ASL.

Simian virus 40 maturation: chromatin modifications increase the accessibility of viral DNA to nuclease and RNA polymerase

The accessibility of extracellular and nuclear simian virus 40 (SV40-M and SV40-I, respectively) virion chromatin DNAs to micrococcal nuclease, DNase I, BglI, EcoRI, and RNA polymerase was examined. Our results support the following conclusions: (i) the intranucleosomal DNA of SV40-I chromatin, similar to the precursor 75S chromatin complex, is resistant to enzymatic activity; and (ii) SV40-M virion chromatin is modified in a manner which increases the accessibility of viral DNA to enzymes, and the distinction between nucleosomal DNA and linker DNA is absent. Micrococcal nuclease digestion of SV40-I virion chromatin gave a typical nucleosomal DNA ladder pattern with a repeat unit of 205 base pairs of DNA. SV40-I chromatin was sensitive to cleavage with endonuclease BglI, but not with EcoRI. When SV40-I virion chromatin was used as a template, the rate of incorporation of ribonucleoside triphosphates into RNA was 5% of that obtained with naked form SV40 form I DNA. Micrococcal nuclease digestion of SV40-M virion chromatin resulted in submonomeric DNA fragments of approximately 55 base pairs, but no larger repeating unit of DNA was observed. SV40-M virion chromatin was sensitive to cleavage with either BglI or EcoRI and was approximately 20% more susceptible to digestion with DNase I than was SV40-I virion chromatin. The transcriptional efficiency of the extracellular virion chromatin was almost equivalent to that of naked SV40 form I DNA and was 16-fold higher than the rate observed with nuclear virion chromatin. The increased transcriptional activity was dependent upon the presence of nonhistone viral protein VP1 or VP2 or both.