Biomedical subjects

J Greiner

Publications and source records attributed to J Greiner.

At least 37 records · Page 2Linked to original sources

PubMed1999

Corpus callosum size in schizophrenia--a magnetic resonance imaging analysis.

Previous MRI studies have shown differences in corpus callosum size between schizophrenic patients and controls. The corpus callosum (CC), as the main interhemispheric fiber tract, plays an important role in interhemispheric integration and communication. Though MRI studies suggest smaller CC in schizophrenia, there are still conflicting findings. Using in vivo magnetic resonance imaging, it was investigated whether the midsagittal area of CC differs between twenty-three right-handed male schizophrenic patients and twenty-three matched controls. Total CC area, five subregions of CC, total brain volume, gray and white matter were measured. No differences between schizophrenic patients and controls were found regarding all CC measurements, total brain volume, and gray matter tissue. However, a significant reduction of white matter tissue in the patient group emerged. There was no correlation between CC morphology and clinical variables such as age of onset, length of illness or symptom severity. Interestingly, five schizophrenic patients with a positive family history of schizophrenia showed significant reduction of the subregion C3, associated with a reduced total brain and gray and white matter volume. Significant reduction in the CC and its subregions was not confirmed in this group of patients with schizophrenia. In the subgroup of schizophrenic patients with a positive family history of schizophrenia, a significant reduction of the subregion corresponding to a part of the trunk of the CC was found.

Adult↗

PubMed1999

Phase behavior of fluorocarbon and hydrocarbon double-chain hydroxylated and galactosylated amphiphiles and bolaamphiphiles. Long-term shelf-stability of their liposomes.

This paper describes the morphological characterization, by freeze-fracture electron microscopy, and the thermotropic phase behavior, by differential scanning calorimetry and/or X-ray scattering, of aqueous dispersions of various hydroxylated and galactosylated double-chain amphiphiles and bolaamphiphiles, several of them containing one or two hydrophobic fluorocarbon chains. Colloidal systems are observed in water with the hydroxylated hydrocarbon or fluorocarbon bolaamphiphiles only when they are dispersed with a co-amphiphile such as rac-1,2-dimyristoylphosphatidylcholine (DMPC) or rac-1,2-distearoylphosphatidylcholine (DSPC). Liposomes are formed providing the relative content of bolaamphiphiles does not exceed 20% mol. Most of these liposomes can be thermally sterilized and stored at room temperature for several months without any significant modification of their size and size distribution. The hydrocarbon galactosylated bolaamphiphile HO[C24][C12]Gal forms in water a lamellar phase (the gel to liquid-crystal phase transition is complete at 45 degrees C) and a Im3m cubic phase above 47 degrees C. The fluorocarbon HO[C24][F6C5]Gal analog displays a more complex and metastable phase behavior. The fluorinated non-bolaform galactosylated [F8C7][C16]AEGal and SerGal amphiphiles form lamellar phases in water. Low amounts (10% molar ratio) of the HO[C24][F6C5]Gal or HO[C24][C12]Gal bolaamphiphiles or of the single-headed [F8C7][C16]AEGal improve substantially the shelf-stability of reference phospholipon/cholesterol 2/1 liposomes. These liposomes when co-formulated with a single-headed amphiphile from the SerGal series are by far less stable.

Calorimetry, Differential Scanning↗

PubMed1999

University of Iowa Hospital and Clinics: outcomes management.

Delivery of quality patient care and management of patient outcomes is critical to the success of academic medical centers in the ever-changing health care market. The University of Iowa Hospitals and Clinics (UIHC) promotes quality care through the provision of organizational structures and processes that are described in this article. In addition, quality of care and outcomes management are described by members in various roles within the UIHC health care system. It is the authors' belief that understanding quality from these various perspectives helps UIHC work across departments to achieve excellence in patient care.

Attitude of Health Personnel↗

PubMed1999

Strategies in the development of recombinant vaccines for colon cancer.

A new era involving the evaluation of recombinant vaccines for colon cancer has begun with the concurrent emergence of insights and technologies in the fields of molecular biology and immunology. These advances include (I) the identification and cloning of an array of genes associated with the neoplastic process, such as oncogenes, suppressor genes, genes encoding oncofetal antigens, and tissue lineage determinants; (2) the development of a variety of viral and bacterial vectors to deliver and present gene products; (3) the identification of numerous T-cell costimulatory molecules and the knowledge of their mode of action; (4) the cloning and analysis of the modes of action of an array of cytokines and other immunomodulatory molecules; and (5) a more sophisticated knowledge of the mode(s) of antigen presentation and T-cell activation.

Adjuvants, Immunologic↗

PubMed1998

Photometry and spectroscopy of the GRB 970508 optical counterpart

An optical transient within the error box of the gamma ray burst GRB 970508 was imaged 4 hours after the event. It displayed a strong ultraviolet excess, and reached maximum brightness 2 days later. The optical spectra did not show any emission lines, and no variations on time scales of minutes were observed for 1 hour during the decline phase. According to the fireball and afterglow models, the intensity should rise monotonically before the observed optical maximum, but the data indicate that another physical mechanism may be responsible for the constant phase seen during the first hours after the burst.

Journal Article↗

PubMed1998

Cancer vaccine development.

A new era involving the evaluation of recombinant cancer vaccines has begun with the concurrent emergence of insights and technologies in the fields of molecular biology and immunology. These advances include: The identification and cloning of an array of genes associated with the neoplastic process, such as oncogenes, suppressor genes, genes encoding oncofoetal antigens and tissue-lineage determinants. The development of a variety of viral and bacterial vectors to deliver and present gene products. The identification of numerous T-cell costimulatory molecules and an understanding of their mode of action. The cloning and analysis of the modes of action of an array of cytokines and other immunomodulatory molecules. More sophisticated knowledge of the mode(s) of antigen presentation and T-cell activation. One current challenge in cancer therapy is the delineation of strategies toward the rational design and implementation of recombinant vaccines that will be of therapeutic benefit to cancer patients and/or members of groups at high risk for specific neoplasias. Numerous concepts are emerging in this regard. The study of immunologic intervention using laboratory animal models demonstrates that no one approach will prevail for all cancer types or, perhaps, for the various stages of the neoplastic process of a given tumour type. The immunological role(s) of CD8+, CD4+, natural killer and other cell types, as well as the roles of antibodies, must all be taken into consideration. This article reviews some of the strategies currently undergoing evaluation toward the development of recombinant vaccines for several carcinoma types.

Journal Article↗

PubMed1997

Seven-week continuous-infusion paclitaxel plus concurrent radiation therapy for locally advanced non-small cell lung cancer: a phase I study.

The goal of this National Cancer Institute-sponsored phase I trial is to determine the feasibility, toxicity, and pharmacokinetics of continuous-infusion (24 hr/d, 7 d/wk, 7 weeks total) intravenous paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) when combined with standard, curative-intent radiation therapy (RT) for previously untreated, locally advanced non-small cell lung cancers. Eligible patients have locally advanced (T4NXM0 or TXN2-3M0) non-small cell cancer ineligible for potentially curative surgical resection, a good performance status, adequate hematologic, hepatic, and renal functions, and no distant metastases. All patients receive a total tumor dose of 64.8 Gy megavoltage RT in 7 weeks at 1.8 Gy once daily, 5 d/wk. Paclitaxel is delivered by continuous intravenous infusion starting 48 hours before RT and continuing for its duration. The dose of paclitaxel is escalated in cohorts of three patients in a standard phase I design. To date, 16 patients have entered the trial, and 15 are evaluable for toxicity in this ongoing study. Paclitaxel dose is currently at a 6.5 mg/m2/d dose level, with no dose-limiting toxicity recorded thus far. One patient at the highest dose level has had grade 2 pneumonitis. With the exception of anemia, toxicities are those that would be expected from RT alone. A slowly progressive normocytic anemia with no renal dysfunction was found to be associated with an acquired hypoerythropoietin state. These findings indicate that this therapy is feasible and well tolerated through current dose levels, with no dose-limiting toxicity. Dose escalation is ongoing.

Antineoplastic Agents, Phytogenic↗

PubMed1997

[Endosonographic determination of the volume of anal sphincter muscles as a parameter for continence outcome in childhood].

The volumes of the external and internal anal-sphincter muscles, determined by three-dimensional (3d) endosonography, are linear to each other and to the body-height and body-surface ratios in normal children. In patients with an operation of the sphincter muscles, the reduced volume of the external sphincter system permits a differentiation of incontinent children; the volume of the internal sphincter muscles, however, doesn't give a significant difference nor does the muscle-thickness. An acceptable estimation of the sphincter muscles volume can be made with conventional endosonography by planimetry of the muscle tissue in four representative axial cut-planes and by measuring of the sphincter-length.

Adolescent↗

PubMed1996

Vesicles made of glycophospholipids with homogeneous (two fluorocarbon or two hydrocarbon) or heterogeneous (one fluorocarbon and one hydrocarbon) hydrophobic double chains.

The vesicle-forming ability of the new anionic double chain glycophospholipids 1-4, with either two hydrocarbon or two perfluorocarbon chains, or a mixed double chain (one fluorinated, one hydrogenated), was investigated. When dispersed in water, 1a-c,e, 2b,c and 4b,c readily gave heat-sterilizable vesicles, 30-70 nm in diameter. The galactose and mannose-based fluorinated vesicles were also highly stable on aging. The 6-substituted glucose derivatives 3 formed tubules that reversibly interconverted into vesicles, depending on temperature. The leakage rate in buffer of carboxyfluorescein or calcein from vesicles made from 1a-c,e 2b,c and 4b,c depended on the sugar (t1/2 galactose > mannose > glucose). It decreased significantly with increasing fluorination and length of the hydrophobic tails. The mixed perfluorocarbon/hydrocarbon-tailed amphiphiles were found to be miscible with both the two fluorocarbon chains and the two hydrocarbon chains derivatives. Such admixing tended, however, to increase the small unilamellar vesicles' permeability. In buffered serum, all the vesicles investigated were highly permeable, but incorporation of cholesterol or DSPC in vesicles made of 1e significantly reduced their permeability in serum. The new vesicle and membrane components have i.v. maximum tolerated doses as high as 500 mg/kg body weight in mice; hemolytic activity sharply decreases with increasing degree of fluorination.

Animals↗

PubMed1996

[Splenectomy in osteomyelofibrosis. Indications and outcome].

Osteomyelofibrosis is a myeloproliferative disorder in which fibrosis and sclerosis finally lead to bone marrow obliteration. Liver and spleen compensate for bone marrow loss with extramedullary hematopoiesis. In some patients the resulting splenomegaly causes severe symptoms such as local compression, thrombocytopenia and hemolytic anemia. In such patients, splenectomy is the only promising treatment, although it represents a significant risk.

Adult↗

PubMed1995

Dexverapamil to overcome epirubicin resistance in advanced breast cancer.

Resistance to cytotoxic chemotherapy is a major problem in the management of patients with metastatic breast cancer. Various data suggest P-glycoprotein-associated multidrug resistance (MDR) to be a relevant resistance mechanism in this tumor. The purpose of this study was to evaluate feasibility and activity of combining oral dexverapamil, a second-generation chemosensitizer currently in clinical development for MDR reversal, with epirubicin in patients with epirubicin-refractory high-risk metastatic breast cancer. Patients first received epirubicin alone at 120 mg/m2. In cases of clinical refractoriness, epirubicin was continued at the same dose and schedule but supplemented with oral dexverapamil. Dexverapamil was given at 300 mg every 6 h for a total of 13 doses and commenced 2 days prior to epirubicin administration. At the time of this interim analysis, 41 patients had received epirubicin alone and 20 proceeded to treatment with epirubicin plus dexverapamil. Of the 20 patients, 14 were considered evaluable for toxicity and activity. Addition of dexverapamil resulted in a significant decrease in mean heart rate and blood pressure as well as prolongation of PQ time as compared to epirubicin alone. However, these cardiovascular effects of dexverapamil were usually mild, and subjective tolerance of treatment was good. In 7/14 patients, dose escalation of dexverapamil was feasible. Dexverapamil had no effect on epirubicin toxicities and did not require reduction of the epirubicin dose. In 2/14 patients, the addition of dexverapamil to epirubicin was able to convert progressive disease and no changes respectively, into partial responses. In 3 patients with progressive disease, addition of dexverapamil temporarily prevented further tumor progression. Analyses of dexverapamil and nor-dexverapamil plasma levels, of in vitro reversal activity of patient sera containing dexverapamil, and of epirubicin pharmacokinetics without and with dexverapamil are currently in progress. Addition of oral dexverapamil to epirubicin 120 mg/m2 proved to be feasible in a multiinstitutional setting. Patient accrual is continuing to determine whether dexverapamil is capable of overcoming epirubicin refractoriness in a significant number of patients with metastatic breast cancer.

Adult↗

PubMed1994

Amphiphilic sugar phosphates with single or double perfluoroalkylated hydrophobic chains for use in oxygen and drug delivery systems.

New anionic amphiphiles with a phosphate ester junction between the fluorophilic-lipophilic tail and the sugar-based hydrophilic head were synthesized and evaluated. The single hydrophobic chain surfactants 1 a, b and 2a allowed the preparation of stable and fine highly concentrated emulsions of perfluorodecalin or perfluoroocytl bromide, either when used alone or in conjunction with egg yolk phospholipids (EYP). Surfactants 3d, 5d, 6d and 6e, with two hydrophobic chains, one fluorinated the other not, gave liposomal structures, and displayed encapsulation properties for carboxyfluorescein. The phosphodiesters tested cause no significant inhibition of the growth and viability of Namalva cell cultures (0.1-1 g/L range). Single chain phosphodiesters manifest no detectable hemolytic activity (at 100 g/L for 1a) whereas double chain compounds do moderately (ca 20% hemolysis at 20 g/L). The maximum tolerated dose compatible with the survival of all of a series of 10 intravenously injected mice is in 130 mg/kg body weight range.

Alkylation↗

PubMed1994

Novel injectable fluorinated contrast agents with enhanced radiopacity.

Novel emulsions containing iodinated fluorinated radiopaque (IFR) molecules were prepared and evaluated as injectable contrast agents with prolonged intravascular persistence. Various stable IFR/egg yolk phospholipid emulsions were produced, heat-sterilized, and tested as to their radiopacity, shelf-stability and in vivo tolerance. No significant change in mean particle sizes was observed over a 3-month storage period at 40 degrees C. Intravenous injection of an emulsion of a 0.39 g/kg bw dose of a typical IFR, C6F13CH = CIC6H13 (F6H6IE) in rabbits led to high contrast in the liver and spleen. The same radiopacity of the liver was achieved with 7 times less IFR than perfluorooctyl bromide. Histological examination after 24 h, and blood analysis after 24, 48 h and 7 days, demonstrated normal functioning of the liver, even when high concentrations of IFR were present. The neat IFR was tolerated i.p. in mice at a 45 g/kg bw dose. Emulsified IFR was tolerated in rats and mice i.v. at a 8 g/kg bw dose. The iodinated fluorinated molecule tested appears promising for the formulation of new contrast agents for diagnosis.

Animals↗

PubMed1994

Research utilization in critical care: an exemplar.

The authors describe the process and outcome of implementing a research-based pain management protocol in four adult critical care units at a large, Midwestern tertiary care center. The project was initiated and directed by members of the divisional research committee. Strategies used to change practice included determining if pain management was a problem via quality assessment monitors, surveying nurses regarding their knowledge and attitude toward pain management, educating staff members about the research base for the practice change, using change champions in each unit, and developing a core group of nurses in each unit to facilitate the change. Outcomes of this research utilization project include a 41% decline in the number of patients in pain, a 44% decline in pain intensity, and improvement in nurses knowledge about pain.

Clinical Nursing Research↗

PubMed1992

Immunogenicity and safety of a recombinant vaccinia virus vaccine expressing the carcinoembryonic antigen gene in a nonhuman primate.

We have previously reported the development of a recombinant vaccinia virus vaccine expressing the human carcinoembryonic antigen (CEA) gene, designated rV(NYC)-CEA. This construct has been shown to elicit specific anti-CEA immune responses and an antitumor effect in a murine tumor model. In the studies reported here, the safety and immunogenicity of this recombinant vaccinia virus were evaluated in a rhesus monkey model. Human CEA is a M(r) 180,000 glycoprotein expressed in approximately 90% of gastrointestinal carcinomas and in some breast and non-small cell lung carcinomas. This family also includes normal cross-reacting antigen (NCA). Rhesus monkeys, like humans, have some NCA on the surface of their granulocytes. Eight monkeys were immunized 3 or 4 times by skin scarification with the recombinant CEA vaccine and four monkeys received wild-type vaccinia virus as control. After three vaccinations, all rV(NYC)-CEA-vaccinated animals exhibited a strong anti-CEA antibody response as measured by enzyme-linked immunosorbent assay. The functional ability of these antibodies to mediate lysis of a CEA-bearing tumor cell was demonstrated using human effector cells. This response could be enhanced by interleukin 2. Cellular immunity to CEA was measured by delayed-type hypersensitivity upon intradermal challenge with purified CEA. Only those animals receiving the recombinant vaccine displayed significant anti-CEA responses. Furthermore, peripheral blood mononuclear cells from immunized monkeys were found to proliferate in response to CEA stimulation. All vaccinated monkeys developed local skin irritation at the site of the vaccination, regional lymphadenopathy, and low-grade fevers after immunization. Following immunization with rV(NYC)-CEA, the response was consistent with the usual constitutional symptoms seen with human smallpox virus immunization. Blood counts, differentials, and hepatic and renal chemistries remained normal in all animals throughout the study and for up to 1 year following the primary vaccination. No evidence of immunological cross-reactivity to NCA was found by either a fall in the granulocyte count or analyses for anti-NCA antibodies. Thus, the rV(NYC)-CEA vaccine appears to be safe in rhesus monkeys. The administration of a CEA recombinant vaccine to rhesus monkeys induces both a humoral and a cell-mediated immune response directed against human CEA.

Animals↗

PubMed1992

Synthesis of D-glucose 3- and 6-[2-(perfluoroalkyl)ethyl] phosphates: a new type of anionic surfactant for biomedical use.

D-Glucose 3- and 6-[sodium 2-(perfluoro-hexyl or -octyl)ethyl phosphates) have been synthesized by condensation of 1,2,3,4,-tetra-O-acetyl-beta-D-glucopyranose and 1,2:5,6-di-O-isopropylidene-alpha-D-glucofuranose with 2-(perfluoroalkyl)ethylphosphoroditriazolides followed by O-deacetylation or deacetalation. The structures of the compounds were established on the basis of 1H-, 19F-, 31P-, and 13C-NMR data. These salts display strong surface activities and appear to have good biocompatibility.

Biocompatible Materials↗

PubMed1992

Perfluoroalkylated surfactants: relationships between structure and acute toxicity in mice.

New single chain neutral, and single and double chain zwitterionic perfluoroalkylated surfactants or co-surfactants have been evaluated for in vivo applications. A study of the relationship between structure and acute toxicity in mice is presented. Acute toxicity evaluations i.v. in mice indicate the following trends (increasing tolerance): zwitterionic single-chain less than neutral single-chain less than zwitterionic double-chain and, where the polar head is concerned, single-chain compounds: phosphocholine less than phosphoramidate less than trehalose approximately sucrose less than maltose less than xylitol.

Animals↗

PubMed1992

[In vitro proliferation of human bone marrow cells--inhibition by components of Candida albicans].

Candida albicans (CA) components influence the proliferation of human bone marrow cells in vitro (colony-forming assay). Number of colonies per 10(5) bone marrow cells after cultivation with rHuGM-CSF (maximal plateau colony formation): 46.2 +/- 9.1 (n = 6); after cultivation with rHuGM-CSF in combination with CA proteins: 0.05 mg protein/ml: 33.4 +/- 4.6 (n = 3); 0.10 mg protein/ml: 20.8 +/- 3.6 (n = 3).

Bone Marrow Cells↗