Human gene marker/therapy clinical protocols.
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Biomedical subjects
Publications and source records attributed to J Rubin.
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The regulatory regions for transcriptional control of the MCSF gene are unknown. We examined regulatory control in a 774-bp murine MCSF promoter transfected into MC3T3-E1 osteoblast-like and COS-7 cells. Deletion of upstream sequence from -635 increased basal activity of the promoter by at least four-fold, an increase that was maintained when PU.1, NFkappaB and Egr1/Sp1 consensus sequences were subsequently removed. Mutagenesis identified a suppressor element between -635 and -642 from the transcriptional start site and an oligonucleotide representing this sequence was retarded by nuclear cell protein. TNFalpha (1 ng/ml), PTH (5x10(-8) M), and IL-1alpha (100 pg/ml), which increased MCSF protein secretion, failed to enhance the transcriptional rate of the full-length promoter. TNFalpha was able to stimulate transcription of a heterologous reporter transfected into COS-7 containing multiple copies of the murine MCSF NFkappaB site inserted before a minimal promoter. In contrast, deletion of the same NFkappaB response element increased basal activity in the native promoter. Thus, the NFkappaB sequence may act as a negative regulator in the context of the endogenous promoter. Our results indicate that constitutive transcriptional activity conferred by the MCSF promoter may be damped by a suppressor protein. Transcriptional regulation, however, does not appear to be a major stimulatory mechanism for MCSF secretion.
Oscillators in networks may display a variety of activity patterns. This paper presents a geometric singular perturbation analysis of clustering, or alternate firing of synchronized subgroups, among synaptically coupled oscillators. We consideroscillators in two types of networks: mutually coupled, with all-to-all inhibitory connections, and globally inhibitory, with one excitatory and one inhibitory population of oscillators, each of arbitrary size. Our analysis yields existence and stability conditions for clustered states, along with formulas for the periods of such firing patterns. By using two different approaches, we derive complementary conditions, the first set stated in terms of time lengths determined by intrinsic and synaptic properties of the oscillators and their coupling and the second set stated in terms of model parameters and phase space structures directly linked to parameters. These results suggest how biological components may interact to produce the spindle sleep rhythm in thalamocortical networks.
The cancer treatment-related diarrhea caused by acute graft-versus-host disease (GVHD) and chemotherapeutic agents, particularly fluoropyrimidines and irinotecan, significantly affects patient morbidity and mortality. The mechanisms causing cancer treatment-related diarrhea are not fully understood, but histopathologic evidence points to a multifactorial process that causes an absorptive and secretory imbalance in the small bowel. Cancer treatment-related diarrhea could be life-threatening, yet assessment and treatment are not currently standardized. Several clinicians participated in a closed roundtable meeting to review the mechanisms of chemotherapy-induced diarrhea (CID) and GVHD-induced diarrhea, management issues in cancer treatment-induced diarrhea, and pharmacologic approaches to treatment. The meeting produced a proposal for new treatment guidelines and an algorithm, which include the use of octreotide for the management of CID- and GVHD-induced diarrhea. The development of diarrhea assessment guidelines that expand on the current National Cancer Institute criteria and allow for better patient management was also proposed.
Normal dynamic loading prevents bone resorption; however, the means whereby biophysical factors reduce osteoclast activity are not understood. We show here that mechanical strain (2% at 10 cycles per minute) applied to murine marrow cultures reduced 1, 25(OH)(2)D(3)-stimulated osteoclast formation by 50%. This was preceded by decreased expression of osteoclast differentiation factor (ODF/TRANCE). RT-PCR for ODF/TRANCE revealed that ODF/TRANCE mRNA in strained cultures was 59 +/- 3% of that seen in control cultures. No significant effects on total cell count, thymidine uptake, or alkaline phosphatase activity were induced by strain. To isolate the cell targeted by strain, primary stromal cells were cultured from marrow. Mechanical strain also reduced mRNA for ODF/TRANCE to 60% that of control in these cells. In contrast, mRNA for membrane-bound macrophage colony-stimulating factor was not significantly affected. Soluble ODF ( approximately 2 ng/ml) was able to reverse the effect of strain, returning osteoclast numbers to control. Because osteoclast formation is dependent upon ODF/TRANCE expression, strain-induced reductions in this factor may contribute to the accompanying reduction in osteoclastogenesis.
Responsiveness to 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] may be diminished in osteoporosis and inflammatory arthritis. The inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) is produced in excess in these disorders and has been shown to decrease osteoblast transcriptional responsiveness to vitamin D and to inhibit the binding of the vitamin D receptor (VDR) and its nuclear partner the retinoid X receptor (RXR) to DNA. Previous studies have shown that a vitamin D (VDRE) or retinoid X DNA response element (RXRE) is sufficient to confer TNF-alpha inhibition of vitamin D or retinoid-stimulated transcription in the absence of known TNF-alpha-responsive DNA sequences. We tested the hypothesis that the TNF-alpha-stimulated transcription factor nuclear factor (NF)-kappaB could, in part, mediate TNF-alpha action by inhibiting the transcriptional potency of the VDR and RXR at their cognate cis regulatory sites. Osteoblastic ROS 17/2.8 cells transfected with a dose of NF-kappaB comparable to that stimulated by TNF-alpha decreased 1,25(OH)(2)D(3)-stimulated transcription. This inhibitory effect of NF-kappaB was not observed on basal transcription of a heterologous reporter in the absence of the VDRE. The effects of NF-kappaB and TNF-alpha were comparable but not additive. COS-7 cells were cotransfected with reporters under the regulation of VDRE or RXRE along with vectors expressing VDR, RXR, and NF-kappaB nuclear proteins. Reconstituted NF-kappaB and the NF-kappaB subunit p65 alone, but not p50, dose dependently suppressed basal and ligand-stimulated transcription. p65 overexpression completely abrogated enhanced VDRE-mediated transcriptional activity in response to 1,25(OH)(2)D(3). Electrophoretic mobility shift experiments did not reveal a direct effect of recombinant NF-kappaB or its individual subunits on the binding of heterodimeric VDR-RXR to DNA. These results suggest that TNF-alpha inhibition of hormone-stimulated transcriptional activation may be mediated by activation of NF-kappaB. In contrast, the inhibitory effect of TNF-alpha on binding of receptors to DNA is unlikely to be mediated by NF-kappaB and is not necessary for inhibition of transcription.
Elevated levels of lipoprotein(a) [Lp(a)] and the presence of small isoforms of apolipoprotein(a) [apo(a)] have been associated with coronary artery disease (CAD) in whites but not in African Americans. Because of marked race/ethnicity differences in the distribution of Lp(a) levels across apo(a) sizes, we tested the hypothesis that apo(a) isoform size determines the association between Lp(a) and CAD. We related Lp(a) levels, apo(a) isoforms, and the levels of Lp(a) associated with different apo(a) isoforms to the presence of CAD (>/=50% stenosis) in 576 white and African American men and women. Only in white men were Lp(a) levels significantly higher among patients with CAD than in those without CAD (28.4 versus 16.5 mg/dL, respectively; P:=0.004), and only in this group was the presence of small apo(a) isoforms (<22 kringle 4 repeats) associated with CAD (P:=0.043). Elevated Lp(a) levels (>/=30 mg/dL) were found in 26% of whites and 68% of African Americans, and of those, 80% of whites but only 26% of African Americans had a small apo(a) isoform. Elevated Lp(a) levels with small apo(a) isoforms were significantly associated with CAD (P:<0.01) in African American and white men but not in women. This association remained significant after adjusting for age, diabetes mellitus, smoking, hypertension, HDL cholesterol, LDL cholesterol, and triglycerides. We conclude that elevated levels of Lp(a) with small apo(a) isoforms independently predict risk for CAD in African American and white men. Our study, by determining the predictive power of Lp(a) levels combined with apo(a) isoform size, provides an explanation for the apparent lack of association of either measure alone with CAD in African Americans. Furthermore, our results suggest that small apo(a) size confers atherogenicity to Lp(a).
We develop geometric dynamical systems methods to determine how various components contribute to a neuronal network's emergent population behaviors. The results clarify the multiple roles inhibition can play in producing different rhythms. Which rhythms arise depends on how inhibition interacts with intrinsic properties of the neurons; the nature of these interactions depends on the underlying architecture of the network. Our analysis demonstrates that fast inhibitory coupling may lead to synchronized rhythms if either the cells within the network or the architecture of the network is sufficiently complicated. This cannot occur in mutually coupled networks with basic cells; the geometric approach helps explain how additional network complexity allows for synchronized rhythms in the presence of fast inhibitory coupling. The networks and issues considered are motivated by recent models for thalamic oscillations. The analysis helps clarify the roles of various biophysical features, such as fast and slow inhibition, cortical inputs, and ionic conductances, in producing network behavior associated with the spindle sleep rhythm and with paroxysmal discharge rhythms. Transitions between these rhythms are also discussed.
PURPOSE: The goals of this study were to determine the maximum-tolerated dose and describe the toxicities of the combination of irinotecan and docetaxel administered every 3 weeks to patients with advanced malignancies and, also, to evaluate the effect of irinotecan on the disposition of docetaxel and describe preliminary evidence of antitumor activity. PATIENTS AND METHODS: Eighteen patients received 85 courses (median, two courses; range, one to 15 courses) of treatment with irinotecan, administered over 90 minutes by intravenous infusion, followed by docetaxel, administered over 60 minutes by intravenous infusion. Four escalating dose levels of irinotecan/docetaxel (160/50 mg/m(2), 160/65 mg/m(2), 200/65 mg/m(2), and 200/75 mg/m(2)) were studied. Pharmacokinetic analyses were performed to evaluate the effect of irinotecan on the disposition of docetaxel. RESULTS: The most common and dose-limiting toxicity was myelosuppression, which consisted of neutropenia that was severe (National Cancer Institute common toxicity criteria [NCI CTC] grade 4) but brief (< 5 days) in 11 patients, with three episodes of febrile neutropenia. Nonhematologic toxicities of anorexia, nausea, and stomatitis were mild to moderate (NCI CTC grades 1 and 2), but there was one incidence each of both CTC grade 3 anorexia and nausea. All patients had total alopecia. Diarrhea was dose-dependent and severe in four patients who failed to take adequate antidiarrhea therapy. Five out of 16 assessable patients, one with cholangiocarcinoma, one with leiomyosarcoma, and three with non-small-cell lung cancer, achieved partial remissions. CONCLUSION: The combination of irinotecan and docetaxel causes significant reversible myelosuppression, which was dose limiting but led to no serious sequelae. There was no evidence of a clinically significant interaction using these two agents in this sequence. The combination showed antitumor activity at all the dose levels tested and should be further studied in a number of tumor types. The recommended phase II dose on this schedule is irinotecan 160 mg/m(2) and docetaxel 65 mg/m(2).
Tumor necrosis factor-alpha (TNF-alpha) has a key role in skeletal disease in which it promotes reduced bone formation by mature osteoblasts and increased osteoclastic resorption. Here we show that TNF inhibits differentiation of osteoblasts from precursor cells. TNF-alpha treatment of fetal calvaria precursor cells, which spontaneously differentiate to the osteoblast phenotype over 21 days, inhibited differentiation as shown by reduced formation of multilayered, mineralizing nodules and decreased secretion of the skeletal-specific matrix protein osteocalcin. The effect of TNF was dose dependent with an IC50 of 0.6 ng/ml, indicating a high sensitivity of these precursor cells. Addition of TNF-alpha from days 2-21, 2-14, 7-14, and 7-10 inhibited nodule formation but addition of TNF after day 14 had no effect. Partial inhibition of differentiation was observed with addition of TNF on only days 7-8, suggesting that TNF could act during a critical period of phenotype selection. Growth of cells on collagen-coated plates did not prevent TNF inhibition of differentiation, suggesting that inhibition of collagen deposition into matrix by proliferating cells could not, alone, explain the effect of TNF. Northern analysis revealed that TNF inhibited the expression of insulin-like growth factor I (IGF-I). TNF had no effect on expression of the osteogenic bone morphogenic proteins (BMPs-2, -4, and -6), or skeletal LIM protein (LMP-1), as determined by semiquantitative RT-PCR. Addition of IGF-I or BMP-6 to fetal calvaria precursor cell cultures enhanced differentiation but could not overcome TNF inhibition, suggesting that TNF acted downstream of these proteins in the differentiation pathway. The clonal osteoblastic cell line, MC3T3-E1-14, which acquires the osteoblast phenotype spontaneously in postconfluent culture, was also studied. TNF inhibited differentiation of MC3T3-E1-14 cells as shown by failure of mineralized matrix formation in the presence of calcium and phosphate. TNF was not cytotoxic to either cell type as shown by continued attachment and metabolism in culture, trypan blue exclusion, and Alamar Blue cytotoxicity assay. These results demonstrate that TNF-alpha is a potent inhibitor of osteoblast differentiation and suggest that TNF acts distal to IGF-I, BMPs, and LMP-1 in the progression toward the osteoblast phenotype.
A Phase I study was performed to determine the maximum tolerated dose (MTD), toxicities, and pharmacokinetic profile of irinotecan (CPT-11) and its active metabolites when given on a once-every-3-week schedule. Thirty-four patients with advanced refractory solid malignancies were treated with CPT-11 (240-340 mg/m2) administered as a 90-min i.v. infusion every 3 weeks. Patients were divided into two groups: those with and those without prior abdominal/pelvic (AP) radiotherapy. Gastrointestinal toxicity (nausea, vomiting, and diarrhea) and hematological toxicity (leukopenia and neutropenia) were dose-limiting side effects. Other common toxicities included anorexia, asthenia, and acute cholinergic symptoms (abdominal cramps, diaphoresis, and lacrimation). For patients with no prior AP radiation therapy, the MTD was determined to be 320 mg/m2, whereas those with prior AP radiation therapy had a MTD of 290 mg/m2. Dose-proportional increases in the mean area under the concentration-time curves for CPT-11, SN-38, and SN-38G were not observed over the narrow dose range studied. Mean values of terminal phase half-life, clearance, terminal phase volume of distribution, and steady-state volume of distribution for CPT-11 were 12.4 +/- 1.8 h, 13.0 +/- 3.8 liters/h/m2, 234 +/- 83 liters/m2, and 123 +/- 38 liters/m2, respectively. The pharmacodynamic analyses indicated the strongest correlation to be between SN-38 area under the concentration-time curves and neutropenia (p = 0.60; P = 0.001). A total of five responses (one complete response and four partial responses) were observed in the cohort of 32 patients with previously treated metastatic colorectal carcinoma. In conclusion, gastrointestinal toxicity and hematological toxicity were the dose-limiting toxicities of CPT-11 when administered as a 90-min infusion every 3 weeks. In this trial, the recommended Phase II starting dose for patients with no prior AP radiation therapy was found to be 320 mg/m2; for patients with prior AP radiation, the recommended Phase II starting dose was 290 mg/m2. This once-every-3-week schedule has been incorporated into a Phase I trial of CPT-11 combined with 5-fluorouracil and leucovorin.
Expression of MCSF in bone is important to the regulation of osteoclastogenesis. We show here that tumor necrosis factor-alpha (TNFalpha) increases the production of both soluble (sMCSF) and membrane-bound (mMCSF) macrophage colony stimulating factor by ST2 bone stromal cells. Treatment of ST2 cells with TNFalpha caused sMCSF levels to increase by 394+/-5% from basal; mMCSF rose by 316+/-66% from 30+/-10 per 100,000 cells in the same time. These increases were consistent with increased expression of mRNAs encoding both isoforms. Increases in MCSF mRNA are also seen after stimulation with dexamethasone. To investigate the potential role of NFkappaB in this TNFalpha effect, we treated cells with sodium salicylate (NaS), an inhibitor of NFkappaB translocation. NaS decreased TNFalpha-stimulated NFkappaB activation by 50% as assessed by EMSA. Despite inhibition of NFkappaB signaling, NaS enhanced TNFalpha-stimulated MCSF secretion and did not prevent TNFalpha-stimulated increases in sMCSF mRNA, suggesting that NFkappaB was not involved in TNFalpha effect on the gene. TNFalpha failed to stimulate transcription of a 774 nucleotide MCSF promoter-luciferase reporter transfected into ST2 cells which contained the NFkappaB consensus sequence. Deletion of the seven nucleotides containing the NFkappaB homology response sequence from the MCSF promoter increased basal gene transcription by twofold. TNFalpha thus contributes to an osteoclastogenic environment through upregulation of bone expression of both MCSF isoforms. Our data suggests that NFkappaB is not the major signaling pathway through which this occurs.
Functional loading provides a site-specific signal for the regulation of bone mass and morphology. To determine if strain can inhibit the resorptive component of bone remodeling, osteoclast formation was assessed in marrow cultures plated on flexible membranes subjected to 5% strain for 10 cycles/minute, 24 hours per day. Cultures strained during days 2 through 7 inhibited osteoclast formation to 61+/-7% of control cultures (p < 0.05), a degree of inhibition similar to that observed when the cultures were subjected to strains during only days 2 through 4 but also evaluated on day 7 (67+/-4% of control; p < 0.05). In contrast, straining of cultures during days 5 through 7 had little influence on inhibiting the formation of osteoclasts (94+/-5% of control; no significant difference). The nonuniformly strained substrate was subdivided into three concentric rings. and cultures were used to examine the site-specificity of the inhibition caused by strain. Osteoclast formation in the outermost boundary, which was distended from 3.6 to 5%, was 41+/-7% of that observed in outer regions of control wells. The inhibitory potential of mechanical strain was reduced within the middle ring (73+/-6% of control osteoclasts: p < 0.01), where the strain ranged from 0.2 to 3.6%. The central region, which experienced strains equivalent to those in the middle ring (0.2 to -4% strain), showed inhibition of osteoclast formation to a similar degree (75+/-6% of control). Media harvested from strained cultures failed to inhibit osteoclast formation in unstrained cultures; this implies that the inhibitory effect of strain depended on the direct interaction of the cell with the substrate rather than by a humoral factor. A second device, where a uniform strain was delivered at 1.8% throughout the entire plate, inhibited osteoclast recruitment to 48+/-3.6%, emphasizing that uniform strain in the absence of shear stress constrains osteoclast recruitment. These in vitro experiments can but model the complex environment generated by in vivo mechanical strains: however, they provide the first direct evidence that strain must be considered as inhibitory to osteoclast recruitment.
Achieving adequate pain control in patients with chronic pancreatitis remains a surgical challenge. The quest for a procedure that retains all of the residual pancreatic tissue in the absence of ductal dilatation remains elusive. This study sought to evaluate the feasibility and efficacy of thoracoscopic splanchnicectomy and attempted to outline the surgical anatomy appropriate to an adequate denervation. Of 17 patients considered suitable for the procedure, 16 had a sucessful outcome, which was statistically significant (p < 0.001). The longest follow-up of 30 months suggests that the procedure may be more enduring than percutaneous procedures. However, the surgical anatomy is not predictable owing to the racemose arrangement of the splanchnic fibers, and a long pleurotomy with transection of all medial fibers is necessary to effect denervation. Thoracoscopic splanchnicectomy may effect immediate pain relief with negligible morbidity and absent mortality. Although the follow-up period is short, the patient with the longest follow-up remains pain-free at 30 months. This procedure warrants scrutiny for its role in long-term pancreatic pain control.
At present there is no established standard chemotherapy for advanced gastric cancer. Combination regimens have yielded response rates at times exceeding 50% but with no improvement in survival compared to single agents. This study examined the role of 5-fluorouracil and high-dose levamisole in a phase II setting using survival as the main endpoint. Patients with advanced carcinomas of the stomach or gastroesophageal junction were treated with 5-fluorouracil, 450 mg/m2 IV days 1 to 5, and levamisole, 100 mg/m2 orally three times daily on days 1 to 3, and 50 mg/m2 tid days 4 to 5 every 5 weeks. To allow more rapid accrual and to study a population that more accurately reflects the makeup of patients treated in clinical practice, patients with both measurable and nonmeasurable disease were entered in this study. Two of fifteen (13%) patients with measurable disease experienced a partial response to treatment. The adjusted 1-year survival rate for the 44 patients entered was 29.6%, which is similar to the historical 1-year survival of 30% observed in a group of nearly 400 patients treated in prior North Central Cancer Treatment Group studies. This regimen offers no improvement in therapeutic activity for advanced gastric cancer. This study design, however, allows rapid screening of phase II regimens in patients who would usually be candidates for phase III trials.
BACKGROUND: Measurements of total glycohemoglobin (glycoHb) or hemoglobin A1c are routinely used to evaluate intermediate-to-long term glycemic control in patients with diabetes. However, despite the recent availability of more rapid methods for glycohemoglobin determination, it remains difficult in many institutions to obtain same-day glycoHb determinations in time to assist physicians with management of outpatients with diabetes. Hence, we investigated whether fructosamine, which reflects very recent (2 to 3 weeks) glycemic control and which can be assayed more rapidly in our laboratory, could serve as a useful adjunct to glycoHb for management of these patients. METHODS: Diabetes control in outpatients managed using fructosamine, fasting serum glucose, and glycoHb (concentrations from the prior visit) was compared with that for outpatients monitored using fasting serum glucose and prior glycoHb alone. The relative usefulness of fructosamine, current and prior glycoHb, and "fasting" serum glucose for evaluation and management of outpatients with diabetes was compared. In addition, the acceptance of fructosamine by physicians was evaluated by a questionnaire. RESULTS: Same-day fructosamine concentrations correlated better with current glycoHb than did either prior glycoHb or current fasting serum glucose concentrations. However, the availability of same-day fructosamine results did not objectively improve diabetes control compared with that obtained using only fasting serum glucose values and prior glycoHb concentrations. Nonetheless, most examining physicians stated that same-day fructosamine concentrations helped them significantly with diabetes management, primarily because many patients do not adequately monitor home blood glucose levels. CONCLUSIONS: Fructosamine may be a useful adjunctive test for management of outpatients with diabetes in situations where it is not practical to obtain same-day glycoHb concentrations, for patients less compliant with home glucose monitoring, or where recent changes in insulin dose or clinical presentation might not be reflected in the glycoHb levels.
PURPOSE: The mammographically dense breast or the "difficult-to-interpret mammogram" poses significant clinical and diagnostic imaging concerns. From our experience using Tc-99m sestamibi mammography in more than 650 patients, we share our experience in a pictorial manner and include suggested indications and limitations of this exciting new technique. Examples of Tc-99m sestamibi imaging in six patients with mammographically dense breasts are presented. MATERIALS AND METHODS: All patient examinations were ordered clinically for various indications. Comparison radiographic mammography and, when available, confirmatory pathologic analysis were also done. The examples were chosen from our experience with more than 650 patients at two university hospitals and one outpatient imaging center. RESULTS: Of the six examples presented, four had cancer, one had fibrosis after chemotherapy for ductal cell carcinoma, and one had no evidence of cancer. Tc-99m sestamibi imaging showed no increased uptake in the one patient with no tumor and various degrees of uptake in the other five patients. CONCLUSIONS: Six examples from our clinical experience show the usefulness of Tc-99m sestamibi imaging in patients with mammographically dense breasts. The ability to identify a malignancy or its absence supports the continued use of this procedure in these patients.
We describe two postmenopausal women with ascites and elevated CA-125 level, a serologic marker used to detect ovarian cancer. Both patients had unrecognized liver disease but underwent surgical exploration for suspected ovarian disease, which subsequently revealed benign pelvic organs. Elevated serum CA-125 levels have been reported in many patients with ascites due to liver disease and cirrhosis. Thus, the presence of both ascites and an elevated CA-125 level mandates a thorough elevation for liver disease as well as for a possibility of ovarian carcinoma. These cases outline the common finding and provide insight into the management of patients with ascites and elevated CA-125 values.