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PubMed1994

Molecular basis for sequence selective DNA alkylation by (+)- and ent-(-)-CC-1065 and related agents: alkylation site models that accommodate the offset AT-rich adenine N3 alkylation selectivity.

A detailed evaluation of the DNA alkylation selectivity of (+)-CC-1065, ent-(-)-CC-1065 and a series of aborted and extended analogs possessing the CPI alkylation subunit is detailed and the refinement of a model that accommodates the offset AT-rich adenine N3 alkylation selectivity of the enantiomeric agents is presented. The natural enantiomers bind in the minor groove in the 3'-->5' direction starting from the adenine N3 alkylation site across a 2 base (N-BOC-CPI; i.e. 5'-AA), 3.5 base (CPI-CDPI1/CPI-PDE-I1; i.e. 5'-AAA), 5 base (CC-1065/CPI-CDPI2; i.e. 5'-AAAAA) or 6.5 base (CPI-CDPI3; i.e. 5'-AAAAAA) AT-rich site. In contrast, the unnatural enantiomers bind in the reverse 5'-->3' direction in the minor groove and the binding site necessarily starts at the first 5' base preceding the adenine N3 alkylation site and extends across the alkylation site to the adjacent 3' bases covering an AT-rich site of 2 bases (N-BOC-CPI; e.g., 5'-AA), 5 bases (CC-1065/CPI-CDPI2; eg. 5'-AAAAA), or 6.5 bases (CPI-CDPI3; e.g. 5'-AAAAAA). Notably, the model accommodates the unusual observation that both enantiomers of N-BOC-CPI alkylate the same sites within duplex DNA (5'-AA > 5'-TA) and the required reversed binding orientation of the enantiomeric agents. The reversed binding orientation is required to permit access to the electrophilic cyclopropane and the resulting offset AT-rich alkylation selectivity is the natural consequence of the diastereomeric relationship of the adducts. Three dimensional models of the natural and unnatural enantiomer alkylations are presented which clearly illustrate the offset binding sites. A fundamentally simple model for the CC-1065 DNA alkylation reaction, that accommodates the behavior of both enantiomers, is provided in which the sequence selectivity is derived from the noncovalent binding selectivity of the agents preferentially in the narrower, sterically more accessible AT-rich minor groove, the inherent steric accessibility to the adenine N3 alkylation site that accompanies deep penetration of the agent into the minor groove within an AT-rich site, and the 2 base-pair (N-BOC-CPI), 3.5 base-pair (CPI-PDE-I1/CPI-CDPI1), 5 base-pair (CC-1065/CPI-CDPI2), or 6.5 base-pair (CPI-CDPI3) site size required to permit agent binding in the minor groove at the alkylation site.(ABSTRACT TRUNCATED AT 400 WORDS)

Alkylation↗

PubMed1986

Depletion of nicotinamide adenine dinucleotide in normal and xeroderma pigmentosum fibroblast cells by the antitumor drug CC-1065.

CC-1065 is an extremely potent antitumor antibiotic that forms a well-defined adduct with DNA in which the molecule lies within the minor groove and is covalently attached through N3 of adenine. Addition of CC-1065 to human fibroblast cells produced a prolonged depletion of the nicotinamide adenine dinucleotide (NAD) pool even at extremely low drug concentrations (0.01 microgram/mL). The depletion of NAD by CC-1065 was blocked by 3-aminobenzamide, which is consistent with a NAD depletion mechanism involving poly-(ADP-ribose) synthesis in response to a repair-induced DNA strand breakage event. Significantly, similar extents of NAD depletion were also evident in xeroderma pigmentosum cells of complementation groups A and D following exposure to CC-1065. Since this NAD depletion is presumably associated with repair-induced incision, the repair of CC-1065-DNA adducts can probably take place by a pathway distinct from that involved in repair of more conventional bulky DNA adducts. The prolonged depletion of NAD, even at low doses of drug, suggests that CC-1065 causes DNA damage that results in a delay or block in DNA excision repair between the excision and ligation steps.

Antibiotics, Antineoplastic↗

PubMed1990

Determination of the major tautomeric form of the covalently modified adenine in the (+)-CC-1065-DNA adduct by 1H and 15N NMR studies.

(+)-CC-1065 is an extremely potent antitumor antibiotic produced by Streptomyces zelensis. The potent cytotoxic effects of the drug are thought to be due to the formation of a covalent adduct with DNA through N3 of adenine. Although the covalent linkage sites between (+)-CC-1065 and DNA have been determined, the tautomeric form of the covalently modified adenine in the (+)-CC-1065-DNA duplex adduct was not defined. A [6-15N]deoxyadenosine-labeled 12 base pair non-self-complementary oligomer, d(GGCGGAGTT*AGG).d(CCTAACTCCGCC) (asterisk indicates 15N-labeled base), containing the (+)-CC-1065 most preferred binding sequence 5'AGTTA, was synthesized and modified with (+)-CC-1065. This [6-15N]deoxyadenosine-labeled 12-mer duplex adduct was then studied by 1H and 15N NMR. One-dimensional NOE difference and two-dimensional NOESY 1H NMR experiments on the nonisotopically labeled 12-mer duplex adduct demonstrate that the 6-amino protons of the covalently modified adenine exhibit two signals at 9.19 and 9.08 ppm. Proton NMR experiments on the [6-15N]deoxyadenosine-labeled 12-mer duplex adduct show that the two resonance signals for adenine H6 observed on the nonisotopically labeled duplex adduct were split into doublets by the 15N nucleus with coupling constants of 91.3 Hz for non-hydrogen-bonded and 86.8 Hz for hydrogen-bonded amino protons. Parallel 15N NMR experiments on the [6-15N]deoxyadenosine-labeled (+)-CC-1065-12-mer duplex adduct show a triplet-like signal around -276.9 ppm and coupling constants of 91.5 and 85.6 Hz.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine↗

PubMed2000

Synthesis and evaluation of 1,2,8, 8a-Tetrahydrocyclopropa[c]pyrrolo[3,2-e]indol-4(5H)-one, the parent alkylation subunit of CC-1065 and the duocarmycins: impact of the alkylation subunit substituents and its implications for DNA alkylation catalysis.

The synthesis of 1,2,8,8a-tetrahydrocyclopropa[c]pyrrolo[3, 2-e]indol-4(5H)-one (CPI), the parent CC-1065 and duocarmycin SA alkylation subunit, is detailed. The parent CPI alkylation subunit lacks the C7 methyl substituent of the CC-1065 alkylation subunit and the C6 methoxycarbonyl group of duocarmycin SA, and their examination permitted the establishment of the impact of these natural product substituents. The studies revealed a CPI stability comparable to the CC-1065 alkylation subunit but which was 6x more reactive than the (+)-duocarmycin SA alkylation subunit, and it displayed the inherent reaction regioselectivity (4:1) of the natural products. The single-crystal X-ray structure of (+)-N-BOC-CPI depicts a near identical stereoelectronic alignment of the cyclopropane accounting for the identical reaction regioselectivity and a slightly diminished vinylogous amide conjugation relative to (+)-N-BOC-DSA suggesting that the stability distinctions stem in part from this difference in the vinylogous amide as well as alterations in the electronic nature of the fused pyrrole. Establishment of the DNA binding properties revealed that the CPI-based agents retain the identical DNA alkylation selectivities of the natural products. More importantly, the C6 methoxycarbonyl group of duocarmycin SA was found to increase the rate (12-13x) and efficiency (10x) of DNA alkylation despite its intrinsic lower reactivity while the CC-1065 C7 methyl group was found to slow the DNA alkylation rate (4x) and lower the alkylation efficiency (ca. 4x). The greater DNA alkylation rate and efficiency for duocarmycin SA and related analogues containing the C6 methoxycarbonyl is proposed to be derived from the extended length that the rigid C6 methoxycarbonyl provides and the resulting increase in the DNA binding-induced conformational change which serves to deconjugate the vinylogous amide and activate the alkylation subunit for nucleophilic attack. The diminished properties resulting from the CC-1065 C7 methyl group may be attributed to the steric impediment this substituent introduces to DNA minor groove binding and alkylation. Consistent with this behavior, the duocarmycin SA C6 methoxycarbonyl group increases biological potency while the CC-1065 C7 methyl group diminishes it.

Alkylating Agents↗

PubMed2003

Thalidomide and CC-5013 in multiple myeloma: the University of Arkansas experience.

Based on the activity of single-agent thalidomide in relapsed/refractory multiple myeloma in a landmark phase II study of 169 patients conducted at the University of Arkansas for Medical Sciences (UAMS), UAMS initiated several trials of thalidomide and the more potent thalidomide analog CC-5013. In an ongoing trial evaluating thalidomide plus the proteasome inhibitor bortezomib and dexamethasone in patients with relapsed/refractory disease following stem cell transplantation, approximately 50% of patients have experienced a paraprotein reduction of 50% or greater. In patients without cytogenetic abnormalities, the estimated 12-month event-free and overall survival rates are 69% and 100%, respectively. In a second ongoing trial building on the UAMS Total Therapy I regimen, newly diagnosed patients are randomized to thalidomide or no thalidomide pretransplantation followed by consolidation therapy with dexamethasone and multiagent chemotherapy post-transplantation (Total Therapy II). Although the Total Therapy II regimen appears to be superior to the original Total Therapy I regimen, assessment of the effect of thalidomide on Total Therapy II is pending accrual completion. Lastly, based on the increased potency and reduced toxicity profile of CC-5013 compared with thalidomide, a study of CC-5013 in patients with relapsed/refractory disease following transplantation was initiated. Patients are randomized to CC-5013 25 mg daily for 20 days versus CC-5013 50 mg every other day for 10 days. Preliminary results indicate the superiority of the 25-mg arm, with 40% of patients randomized to that arm experiencing a paraprotein reduction of 50% or greater. These preliminary results corroborate the role for thalidomide and CC-5013 in relapsed/refractory and newly diagnosed multiple myeloma based on the UAMS phase II study as well as several other studies of these agents outside of UAMS.

Adjuvants, Immunologic↗

PubMed1995

Molecular cloning and functional expression of a novel CC chemokine receptor cDNA from a human basophilic cell line.

We report the cloning and characterization of a novel basophil CC chemokin receptor, K5-5, from the human immature basophilic cell line KU-812. The predicted protein sequence of K5-5 shows only 49% identity to the macrophage inflammatory protein-1 alpha/RANTES receptor (CC CKR-1) and 47% identity to monocyte chemotactic protein-1 receptor (b form), suggesting that this cDNA encodes a novel member of the CC chemokine receptor family. Analysis of K5-5 mRNA expression indicates that it is restricted to leukocyte-rich tissues. In addition, we have shown significant levels of K5-5 mRNA in human basophils, which were up-regulated by treatment with interleukin-5. The CC chemokines, Macrophage inflammatory protein-1 alpha, RANTES, and monocyte chemotactic protein-1 were able to stimulate a Ca(2+)-activated chloride channel in Xenopus laevis oocytes injected with K5-5 cRNA, whereas no signal was detected in response to monocyte chemotactic protein-2, macrophage inflammatory protein-1 beta, or the CXC chemokine, interleukin-8. Taken together, these results indicate for the first time the presence of a CC chemokine receptor on basophils, which functions as a "shared" CC chemokine receptor and may therefore be implicated in the pathogenesis of basophil-mediated allergic diseases.

Amino Acid Sequence↗

PubMed2005

Structural requirements for activation of latent platelet-derived growth factor CC by tissue plasminogen activator.

Platelet-derived growth factor C (PDGF-C) is one of four members in the PDGF family of growth factors, which are known mitogens and survival factors for cells of mesenchymal origin. PDGF-C has a unique two-domain structure consisting of an N-terminal CUB and a conserved C-terminal growth factor domain that are separated by a hinge region. PDGF-C is secreted as a latent dimeric factor (PDGF-CC), which undergoes extracellular removal of the CUB domains to become a PDGF receptor alpha agonist. Recently, the multidomain serine protease tissue plasminogen activator (tPA), a thrombolytic agent used for treatment of acute ischemic stroke, was shown to cleave and activate PDGF-CC. In this study we determine the molecular mechanism of tPA-mediated activation of PDGF-CC. Using various PDGF-CC and tPA mutants, we were able to demonstrate that both the CUB and the growth factor domains of PDGF-C, as well as the kringle-2 domain of tPA, are required for the interaction and cleavage to occur. We also show that Arg231 in PDGF-C is essential for tPA-mediated proteolysis and that the released "free" CUB domain of PDGF-C can act as a competitive inhibitor of the cleavage reaction. Furthermore, we studied how the PDGF-C/tPA axis is regulated in primary fibroblasts and found that PDGF-C expression is down-regulated by hypoxia but induced by transforming growth factor (TGF)-beta1 treatment. Elucidating the regulation and the mechanism of tPA-mediated activation of PDGF-CC will advance our knowledge of the physiological function of PDGF-CC and tPA and may provide new therapeutic opportunities for thrombolytic and cardiovascular therapies.

Cells, Cultured↗

PubMed1996

Interleukin-2 regulates CC chemokine receptor expression and chemotactic responsiveness in T lymphocytes.

Several studies have shown that CC chemokines attract T lymphocytes, and that CD45RO+, memory phenotype cells are considered to be the main responders. The results, however, have often been contradictory and the role of lymphocyte activation and proliferation has remained unclear. Using CD45RO+ blood lymphocytes cultured under different stimulatory conditions, we have now studied chemotaxis as well as chemokine receptor expression. Expression of the RANTES/MIP-1 alpha receptor (CC-CKR1) and the MCP-1 receptor (CC-CKR2) was highly correlated with migration toward RANTES, MCP-1, and other CC chemokines, and was strictly dependent on the presence of IL-2 in the culture medium. Migration and receptor expression were rapidly downregulated when IL-2 was withdrawn, but were fully restored when IL-2 was added again. The effect of IL-2 could be partially mimicked by IL-4, IL-10, or IL-12, but not by IL-13, IFN gamma, IL-1 beta, TNF-alpha, or by exposure to anti-CD3, anti-CD28 or phytohemagglutinin. Activation of fully responsive lymphocytes through the TCR/CD3 complex and CD28 antigen actually had the opposite effect. It rapidly downregulated receptor expression and consequent migration even in the presence of IL-2. In contrast to the effects on CC chemokine receptors, stimulation of CD45RO+ T lymphocytes with IL-2 neither induced the expression of the CXC chemokine receptors, IL8-R1 and IL8-R2, nor chemotaxis to IL-8. The prominent role of IL-2 in CC chemokine responsiveness of lymphocytes suggests that IL-2-mediated expansion is a prerequisite for the recruitment of antigen-activated T cells into sites of immune and inflammatory reactions.

CD28 Antigens↗

PubMed2002

Vapor resection: a good alternative to standard loop resection in the management of prostates >40 cc.

BACKGROUND AND PURPOSES: The morbidity of transurethral vesection of the prostate (TURP) necessitates constant attempts at modifications to the standard equipment and technique. Patients with larger prostates (>40 cc) need a longer time for the procedure, and the blood loss, requirement for irrigation fluid, and incidence of postoperative complications tend to be greater. We report on the safety and efficacy of TURP with the thick vapor resection loop compared with the standard wire loop in comparable groups of patients with prostates >40 cc. PATIENTS AND METHODS: We randomized 100 patients with benign prostatic hyperplasia (BPH) into two groups of 50 each which were similar in age. The inclusion criteria included an indication for prostatectomy and prostate size >40 cc. Patients who were on finasteride preoperatively (six) and those who had histopathologic adenocarcinoma of the prostate (three) were excluded. Preoperative evaluation included assessment of International Prostate Symptom Score (IPSS), prostate volume by abdominal ultrasonography, maximum flow rate (Q(max)), and residual urine volume. The two groups were similar in the signs and symptoms of BPH. Patients in Group 1 underwent transurethral vapor resection of the prostate (TUVRP) using the vapor resection loop (Wing trade mark; Richard Wolf, Germany), while patients in Group 2 underwent TURP using a standard wire loop. All procedures were performed by consultant urologists with equivalent experience. We used a Martin ME 401 (Gebruder Martin, Tuttlingen, Germany) electrosurgical generator with settings of 120 to 150 Watts and 50 to 70 W for cutting and coagulating, respectively, for the thick loop and 70 to 80 W and 40 to 50 W for the standard loop. Operating time, resected tissue weight, duration of catheterization, nursing contact time, hospital stay, hemoglobin change, serum sodium concentrations, and any complications were noted and analyzed using the Kruskal-Wallis paired variables test, and P values were calculated. P value <0.04 was considered significant. The IPSS, Q(max), and residual urine volume were reevaluated at 6 months and 1 year after the procedure and compared for the two groups. RESULTS: The median prostate volume was 63 cc and 54 cc in Groups 1 and 2, respectively, and the median resected weight was 20 and 19 g, respectively (P = NS). The differences in operating time (median 45 v 60 minutes; P < 0.0001), intraoperative irrigant use (15 v 21 L; P < 0.0001), and intraoperative blood loss (median 52.5 v 150 mL; P < 0.0001) in the two groups were statistically significant. Peroperative blood loss was estimated by the indicator dilution method of Freedman et al in three 5-mL samples of the irrigant fluid and arriving at the average of the three values and adjusted for the volume of irrigant fluid used. The differences in postoperative irrigant (P < 0.01) and catheter duration (P = 0.04) were also significant. Two patients received blood transfusion in Group 2 and none in Group 1. The difference in the change in hemoglobin and serum sodium postoperatively in the two groups was not statistically significant. The complications were dysuria in six patients lasting for a month and one capsular perforation in Group and incontinence lasting for 6 months in two patients and stricture in one patient in Group 2. The efficacy, assessed with IPSS, Q(max), and residual urine volume, was comparable at 6 months and at 1 year. CONCLUSION: The use of a thick vapor resection loop for TURP coupled with higher generator settings as recommended for them, especially for prostates >40 cc, is beneficial, as it significantly reduces operating time, blood loss, irrigant requirement, nursing contact time, and duration of catheterization, besides providing clear vision during surgery and ease of resection. There was no reduction in efficacy or increase in complications.

Aged↗

PubMed1995

Helix-stabilizing agent, CC-1065, enhances suppression of translation by an antisense oligodeoxynucleotide.

The antitumor antibiotic CC-1065 is known to bind at selected sequences in the minor groove of duplex nucleic acids and to hyperstabilize the duplexes against thermal melting. These properties suggested that CC-1065 may enhance translation inhibition by antisense oligonucleotides directed against a specific mRNA. A 585 bp mRNA transcript containing the equine infectious anemia virus (EIAV) S2 gene and a portion of the env gene was prepared. Also, a complementary 20 mer antisense oligodeoxynucleotide (5'-TGTTGGGTAATAGG-GGTTGA-3') was prepared against a target sequence in the mRNA located near the translational initiation sites of the overlapping S2 and env genes. The center of the target sequence had an expected CC-1065 recognition sequence (5'-UAUUA-3'). Translation in the presence of CC-1065 and antisense was markedly suppressed compared with that of antisense alone. Addition of a sense 20 mer strand, with or without CC-1065, had little or no effect on translation. CC-1065 and related compounds may be useful as ligands for enhancing the stability of sense-antisense duplexes and for promoting the inhibition of translation by antisense oligonucleotides.

Antibiotics, Antineoplastic↗

PubMed1998

Acetoacetyl coenzyme A reductase and polyhydroxybutyrate synthesis in rhizobium (Cicer) sp. Strain CC 1192

Biochemical controls that regulate the biosynthesis of poly-3-hydroxybutyrate (PHB) were investigated in Rhizobium (Cicer) sp. strain CC 1192. This species is of interest for studying PHB synthesis because the polymer accumulates to a large extent in free-living cells but not in bacteroids during nitrogen-fixing symbiosis with chickpea (Cicer arietinum L.) plants. Evidence is presented that indicates that CC 1192 cells retain the enzymic capacity to synthesize PHB when they differentiate from the free-living state to the bacteroid state. This evidence includes the incorporation by CC 1192 bacteroids of radiolabel from [14C]malate into 3-hydroxybutyrate which was derived by chemically degrading insoluble material from bacteroid pellets. Furthermore, the presence of an NADPH-dependent acetoacetyl coenzyme A (CoA) reductase, which was specific for R-(-)-3-hydroxybutyryl-CoA and NADP+ in the oxidative direction, was demonstrated in extracts from free-living and bacteroid cells of CC 1192. Activity of this enzyme in the reductive direction appeared to be regulated at the biochemical level mainly by the availability of substrates. The CC 1192 cells also contained an NADH-specific acetoacetyl-CoA reductase which oxidized S-(+)-3-hydroxybutyryl-CoA. A membrane preparation from CC 1192 bacteroids readily oxidized NADH but not NADPH, which is suggested to be a major source of reductant for nitrogenase. Thus, a high ratio of NADPH to NADP+, which could enhance delivery of reductant to nitrogenase, could also favor the reduction of acetoacetyl-CoA for PHB synthesis. This would mean that fine controls that regulate the partitioning of acetyl-CoA between citrate synthase and 3-ketothiolase are important in determining whether PHB accumulates.

Journal Article↗

PubMed1997

Nisoldipine CC: clinical experience in ischaemic heart disease.

Nisoldipine coat core (CC) is a long-acting calcium channel blocker (CCB) with a slow and smooth onset of action. It is effective in the treatment of angina pectoris, increasing exercise duration, time to ST segment depression and time to onset of angina. The results of two studies reviewed here, in which patients received concomitant treatment with a beta-blocker, showed that the anti-anginal efficacy of nisoldipine CC, 40 mg once daily, measured at trough was comparable with amlodipine, 10 mg once daily, and with diltiazem retard, 120 mg twice daily, and that efficacy was maintained over a 24-hour period. The third trial reviewed here showed that nisoldipine CC was at least as effective as three-times-daily treatment with diltiazem (total dose 240 mg). To date, the effects of nisoldipine CC have been investigated in over 4,000 patients with hypertension and angina pectoris. Clinical experience suggests that once-daily nisoldipine CC is at least as well tolerated as other CCBs, provides consistent efficacy and is a useful treatment in the management of patients with angina pectoris. The CCBs show promising beneficial effects in experimental atherosclerosis and a small number of clinical trials show some effect on the progression of atherosclerosis in coronary artery disease and restenosis following coronary angioplasty. An ongoing long-term trial with nisoldipine CC after coronary angioplasty is discussed.

Amlodipine↗

PubMed1997

Nisoldipine CC: clinical experience in hypertension.

Nisoldipine coat core (CC) is a long-acting formulation of the dihydropyridine calcium channel blocker nisoldipine, suitable for once-daily administration in the treatment of patients with hypertension. Data are reported from three randomized, controlled trials. In two of these, nisoldipine CC was shown to be equivalent in efficacy and tolerability to atenolol in patients with mild to moderate hypertension and to enalapril in elderly patients with hypertension. In a third study using ambulatory blood pressure monitoring in black patients with severe hypertension, nisoldipine CC maintained blood pressure control over the 24-hour dosing period. In addition, regression of left ventricular (LV) mass and improvement in LV function were observed at the end of the 4-month treatment period. Further data are presented from a pharmacokinetic pharmacodynamic modelling study investigating the potential effects of dose-dumping of nisoldipine from the controlled-release formulation, which may occur when the drug is taken with food. This study illustrates the superior control of plasma nisoldipine concentrations and blood pressure provided by the CC compared with an immediate-release formulation, and indicates that an interaction between nisoldipine CC and food is unlikely to cause adverse events. The results of these trials provide further support for the use of nisoldipine CC as an effective agent for the treatment of patients with hypertension, providing consistent antihypertensive efficacy and good tolerability with once-daily administration.

Blood Pressure Monitoring, Ambulatory↗

PubMed1997

Age-related changes in susceptibility of mice to low-virulent mouse hepatitis virus (MHV-2-CC) infection.

This study was performed to examine mouse age-dependent changes in susceptibility to MHV-2-CC-infection and participation of macrophages in such changes in BALB/c mice. One-week-old mice were fully susceptible (mortality, 100%), 2-week-old semi-susceptible (36%), and 3- and 4-week-old fully resistant (0%) to MHV-2-CC, respectively. Such age-dependent differences corresponded well with the differences in the virus titers in the liver, spleen and blood and in the severity of liver lesions. In 1-week-old mice with peritoneal exudate cells (PEC) transferred from 4-week-old mice and infected with MHV-2-CC, a slight prolongation of survival time was recorded, although there was no difference in mortality. In 3-week-old mice infected with MHV-2-CC after silica-treatment to suppress macrophages, there was no significant change in susceptibility. In macrophages infected with MHV-2-CC in vitro, the virus replicated better in macrophages obtained from younger mice. These results suggest that macrophages may play a small role in the age-related development of resistance to MHV-2-CC infection in BALB/c mice.

Aging↗

PubMed1999

Using administrative data to compare the relative effectiveness of amlodipine vs nifedipine CC.

OBJECTIVE: To describe an approach for using claims data to compare the effectiveness of 2 similar drugs used for similar indications within a health maintenance organization. STUDY DESIGN: A database study comparing the effectiveness of amlodipine and nifedipine CC in the initial treatment of hypertension. PATIENTS AND METHODS: The claims records of Pennsylvania Medicaid patients between 18 and 64 years of age with continuous eligibility in 1994 were studied. Pharmacy, hospital, and outpatient claims data were merged, and adult patients receiving the target drugs for the specified indication were identified. The effectiveness of the 2 agents used were compared based on the concept that a change in dispensed medication suggested either an adverse event or lack of effectiveness. Adherence rates, adverse events, and pharmacy and nonpharmacy costs associated with the 2 agents were also compared. RESULTS: Patients receiving amlodipine and nifedipine CC as initial treatment for hypertension had similar demographic characteristics and numbers of comorbid conditions. More patients started on nifedipine CC switched to another calcium channel blocker (15.8% for nifedipine CC vs 10.3% for amlodipine). More patients started on amlodipine switched to another class of antihypertensive agent (13.2% for amlodipine vs 7.3% for nifedipine CC). Patients in both groups received adjunctive antihypertensive drugs at a similar frequency (35% for nifedipine CC vs 42%, for amlodipine). Rates of adherence were similar. In adherent patients, there was no difference in rates of reported adverse events. The nonpharmacy costs were similar between groups. Patients in the amlodipine group also had a trend toward higher overall pharmacy charges (all medications) and higher charges for antihypertensive medications other than the study drugs ($302 vs $188, P = .054). CONCLUSIONS: Claims data are often the best available evidence for comparing the effectiveness of pharmaceuticals in real clinical practice. While these comparisons have inherent limitations, the accuracy of the assessment can be maximized by limiting the assessment to agents with the same specific indications. Other important elements include comparison of crossover rates to other pharmaceuticals in the same class; rates of addition of other pharmaceuticals in the same class, adherence, adverse events, and overall healthcare charges.

Adult↗

PubMed1988

Effects of U-71,184 and several other CC-1065 analogues on cell survival and cell cycle of Chinese hamster ovary cells.

CC-1065 is a very potent antitumor antibiotic which selectively binds in the minor groove of DNA with alkylation at N-3 of adenine. Since therapeutic doses of CC-1065 caused delayed deaths in mice, analogues were synthesized, some of which had significant antitumor activity. The effects of several of these analogues on inhibition of CHO cell survival, cell progression, and their phase-specific toxicity are reported. CC-1065, U-66,664, U-66,819, U-66,694, and U-71,184 all have a left hand segment with an intact cyclopropyl group but have different tail segments. Lethality of these compounds after 2 h drug exposure was in the following order (50% lethal dose in nM in parentheses): CC-1065 (0.06) greater than U-71,184 (1.3) greater than U-66,694 (3.2) greater than U-68,819 (171) greater than U-66,664 (greater than 1200). In general, these compounds did not inhibit progression from G1 to S but slowed progression through S and blocked cells in G2-M. The phase-specific toxicity of U-71,184 and U-66,694 was different from that of CC-1065. CC-1065 was most cytotoxic to cells in M and early G1 and toxicity decreased as cells entered late G1 and S. In contrast, U-66,694 and U-71,184 were most toxic to cells in late G1. The biochemical and cellular effects of U-71,184 were then studied in detail since it was the most active among these analogues. After a 2-h exposure to 3 ng/ml U-71,184, 90% cell kill or growth inhibition was observed whereas 100 ng/ml was needed for similar inhibition of DNA and RNA synthesis. This discrepancy between the doses suggested that inhibition of nucleic acid synthesis may not be causally related to lethality. Further studies showed that when drug was removed after 2 h exposure, DNA synthesis continued to be inhibited whereas RNA and protein synthesis reached levels higher than the control. Therefore, it is likely that at cytotoxic doses the low level of inhibition of DNA synthesis combined with the stimulation of RNA and protein synthesis leads to unbalanced growth and cell death.

Animals↗

PubMed1989

Reduction of redundant shadows using new rotational panoramic radiograph "PM 2002 CC".

Rotational panoramic radiography has diagnostic limitations caused by redundant shadows of the mandibular ramus or the cervical vertebrae. This study compared the appearances of redundant shadows in the PM 2002 CC, a new rotational panoramic radiograph, and the popular Orthopantomograph OP 5. Redundant shadows caused by the mandibular ramus and superimposed on the opposite molar and ramus regions, were carefully analyzed. A considerable difference was observed with respect to x-ray beam alignment. Since the rotational axis of the OP 5 was in the region medial to and behind the third molars, the mandibular ramus created a shadow between the x-ray tube and the rotational axis throughout the period of projection. On the other hand, the rotational axis of the PM 2002 CC was located outside and behind the mandibular ramus during the early stage of projection and with further shifting moved to the region medial to and in front of the mandibular ramus. Accordingly, in the PM 2002 CC, the mandibular ramus was superimposed on the opposite side as a real image and ghost image. The appearance of redundant shadows was influenced by differences in the position of the mandibular ramus in relation to the rotational axis of the x-ray beam. The PM 2002 CC reduced redundant shadows by significantly decreasing the scanning sphere through which x-ray beams from the opposite side project the mandibular ramus. Furthermore, altering the positions of the dry mandibular bone used in the experiments, such as the inclination of the occlusal plane or anterior and posterior shifts, caused greater reduction of redundant shadows in the PM 2002 CC than in the OP 5. Further appearances of redundant shadows caused by metallic wire, plates or bone screws used for the jaw reconstruction were also significantly reduced in the PM 2002 CC.

Humans↗

PubMed1984

Electrolyte composition and equilibrium in hemoglobin CC red blood cells.

The red cells of two patients with homozygous hemoglobin C disease (CC) were found to have reduced cation and water content when compared to the red cells of two normal subjects that contained only hemoglobin A (AA). The reduction in cation content was of such a magnitude that the intracellular chloride and hydroxyl (and proton) concentrations were within normal limits despite a measured reduction in the concentration of impermeant negative anions in CC as compared with AA cells of 40 mEq/kg of dry cell solids. The osmotic coefficient of hemoglobin C in CC cells was found to be similar to that observed for hemoglobin A in AA cells. We found no evidence for increased amounts of bound or osmotically abnormal water in CC cells. The reduction in cell cation content in CC cells is mainly due to a reduction in cell K content. The reduced K content is probably related to an increased ouabain- and furosemide-insensitive pathway for K transport in CC cells.

Acid-Base Equilibrium↗