Biomedical subjects

C S Johnson

Publications and source records attributed to C S Johnson.

At least 55 records · Page 3Linked to original sources

PubMed1996

Integrin activation suppresses etoposide-induced DNA strand breakage in cultured murine tumor-derived endothelial cells.

Tumor endothelium is critical for solid tumor growth and is a potential site for anticancer drug action. Within 2 h, etoposide caused marked DNA strand breakage in xenograft tumor-derived endothelial cells (TDECs). Etoposide-induced DNA breakage was inhibited by culturing TDECs on gelatin, type IV collagen, laminin, fibronectin, and the integrin ligand hexapeptide, GRGDSP, but not the inactive peptide, GRADSP. It was also inhibited when TDECs were on surfaces coated with antibodies to alpha 5, beta 1, or beta 3 integrin subunits and by clustering integrins with soluble antibodies. After 8 h with etoposide, TDECs detached from the monolayer, and 50-kb DNA fragments were seen. Fibronectin inhibited both processes. Thus, integrins are survival factors for TDEC that inhibit the genotoxicity of etoposide and may influence the sensitivity of tumors to drugs.

Animals↗

PubMed1996

Survival after myocardial infarction in rats: captopril versus losartan.

OBJECTIVES: This study sought to compare the effects of angiotensin-converting enzyme inhibition versus angiotensin II receptor blockade on survival in rats with myocardial infarction. BACKGROUND: The effects of specific nonpeptide angiotensin receptor blocking agents on survival after myocardial infarction are unknown. METHODS: Rats with a moderate to large myocardial infarction were treated with captopril (2 g/liter drinking water, n = 87) or losartan (2 g/liter drinking water, n = 96). Therapy was initiated immediately after coronary artery ligation and continued for 1 year. RESULTS: Uncensored median survival in captopril-treated rats that survived at least 48 h was 201.5 days versus 236.0 days for losartan-treated rats (p = 0.066). Median survival censored for rats with lung infections was 201.5 days in captopril-treated rats versus 243.0 days for losartan-treated rats (p = 0.028). Conscious hemodynamic measurements and remodeling data obtained at 1 year in the surviving rats (n = 5 for captopril; n = 9 for losarton) revealed no differences in heart weight, left ventricular pressure, dP/dt, cardiac index, time constant of relaxation or any variable of left ventricular remodeling. The only differences (mean +/- SD) were an increase in heart rate (293 +/- 19 vs. 266 +/- 15 beats/min, p < 0.05) and a decrease in peak developed pressure (153 +/- 21 vs. 180 +/- 16 mm Hg, p < 0.05) in the losartan-treated rats. CONCLUSIONS: We conclude that in this experimental model of heart failure, there was no significant difference between survival after angiotensin II receptor blockade with losartan and with angiotensin-converting enzyme inhibition with captopril.

Angiotensin Receptor Antagonists↗

PubMed1996

Interleukin 1 alpha and gamma-interferon induction of nitric oxide production from murine tumor-derived endothelial cells.

The role of nitric oxide (NO) in vascular function, host tumoricidal activity, and antiinflammatory effects is well documented. A number of cytokines induce NO from a variety of cell types. We have demonstrated in murine models that interleukin 1 alpha (IL-1 alpha) induces acute hemorrhagic necrosis, microvascular injury, and enhanced clonogenic tumor cell kill. Effects on the vasculature are observed only in tumor and not in normal tissues. Using methods established previously in our laboratory, murine tumor-derived and normal endothelial cells were cultured with IL-1 alpha, IFN-gamma, or IL-1 alpha/IFN-gamma at various doses with NO production quantitated through the measurement of nitrite by the Griess reaction. In tumor-derived endothelial cells, we demonstrated that neither cytokine alone was capable of inducing nitrite but that the combination of IL-1 alpha/IFN-gamma induced dose-dependent nitrite, with peak levels observed after 4 days incubation. When tumor-derived, normal yolk sac, mouse brain, or mouse aortic endothelial cells were treated with IL-1 alpha (100 units/ml)/IFN-gamma (10 units/ml), tumor-derived endothelial cells produced significantly more nitrite when compared to the normal endothelial cells. Nitrite production from IL-1 alpha/IFN-gamma was sensitive to the nitric oxide synthase inhibitors, NG-methyl-L-arginine or NG-nitro-L-arginine in a dose-dependent manner. In addition, dexamethasone significantly inhibited nitrite production from IL-1 alpha/IFN-gamma-treated, tumor-derived endothelial cells. These studies suggest that the antitumor activity of IL-1 alpha may be mediated through the production of NO from tumor-derived endothelial cells.

Animals↗

PubMed1996

Priapism.

Priapism in adult patients with sickle cell disease is a devastating complication for which there is no consensus regarding management. Innumerable attempts at pharmacologic and surgical intervention have been employed. Distinction between infarctive low-flow priapism with hypoxia and acidosis and normal-flow priapism without acidosis can be obtained using currently available imaging techniques. Cavernosonography and radionuclide scanning to assess penile hemodynamics are useful in determining whether priapism is of the low-flow type. Advances in our understanding of the physiology of erection have prompted a more physiologic approach to the assessment and management of priapism. Based on this technology, it would be possible to develop a prospective multiinstitutional study, thereby providing sufficient numbers of patients to better evaluate therapy. After the episode of priapism has abated and detumescence has occurred, we recommend that the patient be given the option of beginning a trial of hydroxyurea or another antisickling agent.

Adult↗

PubMed1996

Randomized study of neoadjuvant testicular androgen ablation therapy before radical prostatectomy in men with clinically localized prostate cancer.

PURPOSE: We determined whether 12 weeks of neoadjuvant testicular androgen ablation therapy using a luteinizing hormone-releasing hormone agonist could improve pathological outcomes in men undergoing radical retropubic prostatectomy for clinically localized (stages T1C, T2A and T2B) prostatic carcinoma. MATERIALS AND METHODS: A total of 56 participants was randomized to receive either monthly injections of a luteinizing hormone-releasing hormone agonist at 4-week intervals followed by radical retropubic prostatectomy (28) or to undergo immediate radical retropubic prostatectomy alone (28). Operations were performed via similar technique and all prostatic specimens were processed histologically in their entirety. RESULTS: There was no improvement in pathological outcome using luteinizing hormone-releasing hormone agonist preoperatively compared to surgery alone. Of 28 men undergoing immediate radical retropubic prostatectomy 23 had organ-confined (17) or specimen-confined (6) disease versus 22 of 28 who received luteinizing hormone-releasing hormone neoadjuvant therapy for 12 weeks preoperatively (16 with organ-confined and 6 with specimen-confined disease, p = 1.00). In addition, when the study population was analyzed by pretreatment prostate specific antigen (PSA) levels (10 ng./ml. or less, or greater than 10 ng./ml/) there was also no difference in pathological outcome (p = 0.65 for PSA greater than 10 and p = 0.32 for PSA less than 10). CONCLUSIONS: Neoadjuvant androgen ablation therapy for 12 weeks before radical prostatectomy in patients with clinically localized adenocarcinoma of the prostate does not result in improved pathological outcomes.

Adenocarcinoma↗

PubMed1996

Myocardial infarction in sickle cell disease.

Gross and microscopic findings consistent with acute (three patients) and healed (four patients) myocardial infarction were found in seven (9.7%) of 72 consecutive hearts from patients with sickle cell disease studied after autopsy between 1950 and 1982. Gross obstructive and atherosclerotic lesions were absent in all seven patients, while microthrombi were present in the arterioles of infarcted tissue in two patients. Pathophysiological mechanisms responsible for the infarction are unclear, but anemia, platelet thrombi, coronary vasospasm, and abnormal rheology related to sickle cells may all be important. Chest pain occurred clinically in six of the seven patients and ECG findings typical of infarction were found in two patients. One patient died suddenly. These findings suggest that ischemic heart disease may be present in a significant number of patients with sickle cell disease and should be considered in all patients who complain of chest pain, whether or not the patient is in crisis.

Adult↗

PubMed1996

Effects of amifostine and paclitaxel on growth of human ovarian carcinoma xenografts in the severe combined immune-deficient mouse: preliminary results.

The effects of amifostine on paclitaxel-induced tumor growth delay using in vivo human ovarian cancer models were evaluated. In some mouse strains amifostine causes hypothermia and/or vasodilation, leading to increased spleen weight and ascites that can result in experimental artifacts. We found, however, that amifostine alone at 100 or 200 mg/kg intraperitoneally did not substantially alter body weight, spleen weight, or body temperature in severe combined immune-deficient (scid) mice bearing human 2780 ovarian cancer cells. In a model of minimal tumor burden (tumor cells injected subcutaneously day 0, drug treatment started day 1) scid mice receiving paclitaxel (27 mg/kg intraperitoneally) with or without amifostine had increased survival at day 76 (83% to 100%) compared with mice that did not receive paclitaxel (17% to 33%). For a model of advanced ovarian cancer, mice received tumor cell injections on day 0 and did not begin drug treatment until tumors were palpable (0.2 x 0.2 cm). Paclitaxel given for five repetitive doses significantly decreased tumor growth (P = .0001) in the advanced ovarian cancer model, and these results were the same whether or not mice received amifostine prior to each paclitaxel dose. We conclude that the scid mouse is a good model for evaluating amifostine in vivo, and that there was no evidence of amifostine-induced tumor protection in these scid mouse human ovarian cancer models. In future studies we will evaluate whether the cytoprotective effects of amifostine will allow dose escalation of paclitaxel and result in enhanced antitumor effects.

Amifostine↗

PubMed1995

Blood transfusions and immunophenotypic alterations of lymphocyte subsets in sickle cell anemia. The Transfusion Safety Study Group.

Transfusions purportedly induce dysfunction of cell-mediated immunity in sickle cell anemia (SCA). We studied hematologic and lymphocytic indices in 173 human immunodeficiency virus (HIV)-negative subjects with SCA and 131 black controls. Children aged 1 to 7 years with SCA had leukocyte counts and percentages of granulocytes, monocytes, natural killer cells, and T-cell markers (CD2+CD11b+, CD4+CD26+, CD4+CD29+) that were significantly higher than those for control children. Percent total lymphocytes was decreased for this age group, but the total number of lymphocytes and T and B cell counts were similar to controls. Platelets were not increased. Adolescents (aged 8 to 17 years) and adults (aged > or = 18 years) with SCA had increased total leukocytes and monocytes and lymphocytes counts that remained level instead of decreasing, as did comparably aged controls. Lymphocyte subsets typically increased in count, but their percentage remained similar to children. The exception was CD56+ cell counts, which were increased in adolescents and adults. No lymphocytic subset change suggested impaired cellular immunity, and none could be related to transfusion. Prophylactically transfused patients had higher granulocyte counts, but these may arise from the complications of SCA itself.

Adolescent↗

PubMed1995

Antitumor activity of interleukin-1 alpha and cisplatin in a murine model system.

BACKGROUND: Interleukin-1 alpha (IL-1 alpha) has potent antitumor activity either alone or combined with alkylating agents such as cisplatin and mitomycin C or porfiromycin. Cisplatin is an effective chemotherapeutic agent in the treatment of advanced squamous cell carcinoma of the head and neck (SCCHN). In the murine SCCVII/SF squamous cell carcinoma tumor model, IL-1 alpha induced acute hemorrhagic necrosis and increased clonogenic cell kill. OBJECTIVE: To determine the efficacy of cisplatin and IL-1 alpha, singly and in combination, in the treatment of SCCHN. METHODS: Syngeneic C3H/HeN mice were treated with single-dose, concurrent, intraperitoneal injections of cisplatin and interleukin-1 alpha 14 days after subcutaneous tumor implantation and were monitored for delayed tumor regrowth. RESULTS: Cisplatin alone, but not IL-1 alpha, induced significant delayed tumor regrowth when compared with control. The combination of IL-1 alpha and cisplatin was even more effective in delaying tumor regrowth than cisplatin alone. Fractional tumor volume was significantly reduced in animals treated with the combination of cisplatin and IL-1 alpha compared with those treated with IL-1 alpha alone. CONCLUSIONS: Results of interleukin-1 alpha and cisplatin dose-response experiments reveal that the combination of low-dose cisplatin and interleukin-1 alpha is more effective than high-dose cisplatin alone. Our data suggest that cisplatin and IL-1 alpha may be efficacious in the treatment of SCCHN.

Animals↗

PubMed1995

Effect of treatment for 3 months with human parathyroid hormone 1-34 peptide in ovariectomized cynomolgus monkeys (Macaca fascicularis).

Clinical data suggest that PTH may increase cancellous bone mass at the expense of cortical bone in human beings. In this study, the effects of PTH on whole body, axial and appendicular bone mass were studied in an animal model with Haversian cortical bone remodelling. Ovariectomized, young adult, female cynomolgus monkeys were assigned to Placebo (n = 9) or PTH groups (n = 10). The PTH group received 10 micrograms/kg synthetic human PTH(1-34) peptide by SC injection, 3 days/week for 3 months and the Placebo group received vehicle. Spinal and whole body bone mass were measured by DXA, and proximal tibia, distal radius and mid-radius bone mass were measured by quantitative computed tomography (QCT) at baseline and 3 months. Small, transient increases in serum calcium were observed 4 hours after injection with PTH. Compared to placebo-treated animals, PTH-treated monkeys had no change in whole body bone mass, but a 5% increase in spinal bone mineral density. Cortical bone mass measured by QCT at appendicular sites was not affected by PTH treatment, but there were significant increases in cancellous bone mass in the proximal tibia, and a similar trend in distal radius. PTH stimulated dramatic bone gain in the lumbar spine and at appendicular trabecular bone sites during three months' treatment. There was no evidence of cortical bone loss during the same period.

Absorptiometry, Photon↗

PubMed1994

Potentiation by interleukin 1 alpha of cisplatin and carboplatin antitumor activity: schedule-dependent and pharmacokinetic effects in the RIF-1 tumor model.

We have previously demonstrated that the cytokine interleukin 1 alpha (IL-1 alpha) significantly potentiates the antitumor activity of a variety of chemotherapeutic agents, including cisplatin (cDDP). In studies described here, we examined the potential of combining IL-1 alpha and the platinum analogue carboplatin (CBDCA) and compared the schedule-dependent and pharmacokinetic effects for IL-1 alpha combinations with cDDP and CBDCA. RIF-1 tumor-bearing mice (C3H/HeJ) received i.p. injections of varying doses of CBDCA, alone or concurrently with IL-1 alpha (48 or 480 micrograms/kg). Clonogenic cell kill and tumor regrowth delay were significantly increased when CBDCA was combined with IL-1 alpha, at both doses, compared to either CBDCA or IL-1 alpha alone (P < 0.001 and P < 0.01, respectively). Although pretreatment with IL-1 receptor antagonist blocked the acute tumor hemorrhagic response induced by IL-1 alpha alone, IL-1 receptor antagonist only partially blocked IL-1 alpha enhancement of CBDCA or cDDP-mediated tumor cell kill. The IL-1 alpha enhancement of CBDCA-mediated tumor cell kill was highly schedule dependent, with maximum antitumor activity observed when IL-1 alpha was administered 4-12 h before CBDCA. In contrast, administration of IL-1 alpha from 24 h before or as late as 6 h after cDDP resulted in the same antitumor activity as simultaneous administration of cDDP and IL-1 alpha. Tumor and normal tissue platinum content were significantly increased by IL-1 alpha in animals treated with CBDCA (P < 0.01) but not in those treated with cDDP. The observed differences between cDDP and CBDCA may be explained by their known differential rates of clearance and protein binding affinities and are compatible with an induced alteration in CBDCA pharmacokinetics.

Animals↗

PubMed1994

Gene therapy and endothelial cell targeting for cancer.

The endothelium represents a potentially critical target for gene therapy because of its anatomical location and its importance in the viability in both normal and malignant tissues. Protecting the endothelium of normal tissues, such as the lungs, from the toxic effects of current antineoplastic agents and the destruction of the tumor vasculature are reasonable goals. As a target, however, the endothelium continues to represent a significant challenge. While gene delivery to cultured endothelial cells is possible, improved delivery systems are required, as well as cell-specific promoters, before in vivo gene therapy to important endothelial populations can be accomplished.

Amino Acid Sequence↗

PubMed1994

Enhancement of regression of cervical intraepithelial neoplasia II (moderate dysplasia) with topically applied all-trans-retinoic acid: a randomized trial.

BACKGROUND: Retinoids enhance differentiation of most epithelial tissues. Epidemiologic studies have shown an inverse relationship between dietary intake or serum levels of vitamin A and the development of cervical dysplasia and/or cervical cancer. Pilot and phase I investigations demonstrated the feasibility of the local delivery of all-trans-retinoic acid (RA) to the cervix using a collagen sponge insert and cervical cap. A phase II trial produced a clinical complete response rate of 50%. PURPOSE: This randomized phase III trial was designed to determine whether topically applied RA reversed moderate cervical intraepithelial neoplasia (CIN) II or severe CIN. METHODS: Analyses were based on 301 women with CIN (moderate dysplasia, 151 women; severe dysplasia, 150 women), evaluated by serial colposcopy, Papanicolaou cytology, and cervical biopsy. Cervical caps with sponges containing either 1.0 mL of 0.372% beta-trans-RA or a placebo were inserted daily for 4 days when women entered the trial, and for 2 days at months 3 and 6. Patients receiving treatment and those receiving placebo were similar with respect to age, ethnicity, birth-control methods, histologic features of the endocervical biopsy specimen and koilocytotic atypia, and percentage of involvement of the cervix at study. Treatment effects were compared using Fisher's exact test and logistic regression methods. Side effects were recorded, and differences were compared using Fisher's exact test. RESULTS: RA increased the complete histologic regression rate of CIN II from 27% in the placebo group to 43% in the retinoic acid treatment group (P = .041). No treatment difference between the two arms was evident in the severe dysplasia group. More vaginal and vulvar side effects were seen in the patients receiving RA, but these effects were mild and reversible. CONCLUSIONS: A short course of locally applied RA can reverse CIN II, but not more advanced dysplasia, with acceptable local side effects. IMPLICATIONS: A derivative of vitamin A can reverse or suppress an epithelial preneoplasia, lending further support to the notion that chemoprevention of human cancer is feasible.

Administration, Intravaginal↗

PubMed1994

Isolation and identification of fresh tumor-derived endothelial cells from a murine RIF-1 fibrosarcoma.

Tumor vasculature is anatomically heterogeneous and distinct from the vasculature found in normal mature tissues. Examination of the differences between tumor and normal vasculature is critical to the future design of therapeutic modalities which either target tumor vasculature or potentially enable more efficient delivery of tumor cytotoxic agents. Such efforts to date have been hampered due to the inability to isolate live endothelial cells from solid tumors. We report here the isolation of fresh, noncultured endothelial cells from a C3H/HeJ RIF-1 murine fibrosarcoma through the use of fluorescence-activated cell sorting based on antibody staining for angiotensin-converting enzyme with further characterization by uptake and metabolism of acetylated low-density lipoprotein, factor VIII staining, and electron microscopy.

Animals↗

PubMed1994

Simultaneous measurement of vesicle diffusion coefficients and trapping efficiencies by means of diffusion ordered 2D NMR spectroscopy.

It is demonstrated that the fraction of sucrose entrapped in the aqueous compartment of phospholipid vesicles and the tracer diffusion coefficient of the vesicles can be determined simultaneously with diffusion ordered 2D NMR spectroscopy (DOSY). The sizes of the vesicles are related to the diffusion coefficients by the Stokes-Einstein equation. This method displays 1H-NMR peaks for sucrose in the diffusion dimension at positions corresponding to free and entrapped sucrose, and the areas of these peaks are proportional to the amount of free and entrapped sucrose, respectively. The results were verified by a 1D NMR experiment in which the sucrose peaks were integrated before and after dialysis to remove the external sucrose.

Chemical Phenomena↗

PubMed1994

Diagnosis and treatment of patients with gastroesophageal reflux and noncardiac chest pain.

Patients with noncardiac chest pain frequently have some evidence of gastroesophageal reflux. Yet there are few formal studies on the treatment of what appears to be reflux-related chest pain. The purpose of this study was to evaluate the effectiveness of intensive antireflux therapy in patients with noncardiac chest pain and gastroesophageal reflux and to determine whether patients who will respond to this therapy can be identified through routine esophageal testing. Thirteen patients with noncardiac chest pain and evidence of gastroesophageal reflux were treated with intensive antireflux therapy featuring high-dose ranitidine. Chest pain symptoms were scored from 0 (none) to 4 (severe) at entry into the study and at 8 weeks. Mean symptom scores were 2.9 +/- 0.3 at entry and 0.7 +/- 0.3 at 8 weeks. All patients had improvement, including those with a normal endoscopic or barium study (nine patients) and those for whom earlier standard antireflux therapy had failed (seven patients). Only one patient had a positive acid perfusion test, and only seven had any correlation of chest pain and reflux episodes during ambulatory monitoring. We concluded that many patients with noncardiac chest pain have gastroesophageal reflux, including those for whom an empiric trial of standard antireflux therapy fails. More aggressive antireflux therapy often leads to improvement in symptoms. Diagnostic studies requiring strict correlation of chest pain symptoms and reflux episodes are insensitive methods of determining which patients will respond to antireflux therapy.

Adult↗

PubMed1994

Pedicled osseous flaps.

Craniofacial skeletal defects are most optimally reconstructed with vascularized autogenous bone. There are two methods of achieving such a vascularized osseous reconstruction: microvascular bone transfers and pedicled osseous flaps. Although microvascular composite grafts allow a greater quantity and variety of bone to be moved to the reconstructive site, pedicled osseous flaps remain an excellent reconstructive option. Pedicled osseous flaps are not technically complex, result in minimal donor site morbidity, and demonstrate acceptable reliability in selected cases. This article reviews the realm of pedicled osseous flaps that can be used in craniofacial reconstruction. Although infrequently employed, these useful flaps should remain in the armamentarium of the head and neck surgeon.

Humans↗

PubMed1993

Synergistic enhancement by interleukin-1 alpha of cisplatin-mediated antitumor activity in RIF-1 tumor-bearing C3H/HeJ mice.

Administration of interleukin-1 alpha (IL-1 alpha) plus certain cytotoxic drugs causes substantially greater clonogenic tumor-cell kill and tumor-regrowth delay than does treatment with either agent alone. IL-1 alpha itself has little effect on tumor growth despite its ability to induce acute hemorrhagic necrosis, restrict tumor blood flow, and cause microvascular injury in a variety of murine model systems. To investigate further IL-1 alpha's ability to enhance the antitumor activity of cytotoxic drugs, we initiated studies to examine the effect of IL-1 alpha on cisplatin (cDDP)-mediated cytotoxicity using the RIF-1 tumor system. The antitumor activity of IL-1 alpha and cDDP was quantitated through standard clonogenic tumor-cell survival assays, a tumor hemorrhagic necrosis assay and tumor-regrowth delay studies, with the interaction between IL-1 alpha and cDDP being analyzed through median dose-effect. In vitro, IL-1 alpha had no enhancing effect on the cDDP-mediated tumor-cell kill. For examination of the in vivo efficacy of this regimen, RIF-1 tumor-bearing C3H/HeJ mice (14 days postimplantation) were treated concurrently with single i.p. injections of IL-1 alpha and/or cDDP at various doses. The increased clonogenic tumor-cell kill obtained with IL-1 alpha/cDDP was dose-dependent, with significant enhancement by IL-1 alpha being observed (P < 0.001), even at the lowest doses tested (2 mg/kg and 6 micrograms/kg for cDDP and IL-1 alpha, respectively), but it did not correlate with an increase in tumor hemorrhage. Using median dose-effect analysis, this interaction was determined to be strongly synergistic. When treated animals were monitored for long-term antitumor effects, combinations with IL-1 alpha significantly increased the tumor-regrowth delay and decreased the fractional tumor volume (P < 0.001). These results demonstrate that IL-1 alpha synergistically enhances cDDP mediated in vivo antitumor activity and suggest that the combination of IL-1 alpha and cDDP may have potential therapeutic application in the design of effective treatment modalities for cancer.

Animals↗