Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Modifier”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 775 records · Page 43Linked to original sources
PubMed1991

Biologic response modifiers in primary immunodeficiency disorders.

OBJECTIVE: To propose a new classification for the primary immunodeficiency disorders and to review potential therapeutic applications of biologic response modifiers in these disorders. DATA SOURCE: Relevant articles were identified through a search of MEDLINE using the following indexing terms: primary immunodeficiencies (and subclassifications), and human immunomodulators (and subclassifications). STUDY SELECTION: Articles were critically reviewed and included if relevant. DATA SYNTHESIS: The primary immunodeficiency disorders are classified according to functional abnormalities, specifically, abnormalities in early cellular maturation, differentiation, regulatory cell function, enzymatic function, and cytokine responses. Such a classification clarifies the potential role of biologic response modifiers in primary immunodeficiency disorders. Intravenous gammaglobulin and histamine-2 (H2)-receptor blockers modify regulatory cell function; retinoids modify abnormal cellular differentiation, gene transfer and enzyme replacement can be applied in disorders characterized by specific functional gene abnormalities; and interferons modify abnormal cytokine responses. Interleukin-2, thymic hormones, transfer factor, and levamisole appear to affect multiple functional defects. CONCLUSIONS: Biologic response modifiers are currently important ancillary tools in the treatment of immunodeficiency disorders, and their therapeutic role will become even more important in the future. Multi-center cooperative trials of new and existing agents are needed to fully define their roles and efficacy in the treatment of these disorders.

Cytokines↗
PubMed2002

Low-dose prednisone therapy for patients with early active rheumatoid arthritis: clinical efficacy, disease-modifying properties, and side effects: a randomized, double-blind, placebo-controlled clinical trial.

BACKGROUND: Oral glucocorticoids combined with disease-modifying antirheumatic drugs are beneficial and retard radiologic joint damage in rheumatoid arthritis. OBJECTIVE: To investigate the clinical efficacy, disease-modifying properties, and side effects of low-dose glucocorticoids as monotherapy for previously untreated patients with early active rheumatoid arthritis. DESIGN: 2-year randomized, double-blind, placebo-controlled clinical trial. SETTING: 2 outpatient rheumatology clinics. PATIENTS: 81 patients with early active rheumatoid arthritis who had not been treated with disease-modifying antirheumatic drugs. INTERVENTION: 41 patients were assigned to 10 mg of oral prednisone per day, and 40 were assigned to placebo. Nonsteroidal anti-inflammatory drugs were allowed in both groups. After 6 months, sulfasalazine (2 g/d) could be prescribed as rescue medication. MEASUREMENTS: Clinical variables were assessed at baseline and every 3 months; radiologic studies were performed every 6 months. Adverse effects were documented every 3 months. RESULTS: In the first 6 months, the prednisone group showed more clinical improvement than the placebo group. This effect was not seen after 6 months except in grip strength and the 28-joint score for tenderness. Use of additional therapies was significantly less common in the prednisone group, particularly in the first 6 months. More than 65% of those who completed the study were not taking sulfasalazine. After month 6, radiologic scores showed significantly less progression in the prednisone group than in the placebo group. No clinically relevant adverse effects were observed, except for a higher incidence of osteoporotic fractures in the prednisone group. CONCLUSIONS: Prednisone, 10 mg/d, provides clinical benefit, particularly in the first 6 months, and substantially inhibits progression of radiologic joint damage in patients with early active rheumatoid arthritis and no previous treatment with disease-modifying antirheumatic drugs. Because of their limited disease-modifying effects, glucocorticoids should be combined with disease-modifying antirheumatic drugs in patients with rheumatoid arthritis.

Administration, Oral↗
PubMed1999

Venovenous modified ultrafiltration after cardiopulmonary bypass in children: a prospective randomized study.

BACKGROUND: Cardiopulmonary bypass is associated with the production of both proinflammatory and anti-inflammatory cytokines, the balance of which leads to varying degrees of postoperative systemic inflammation. Arteriovenous modified ultrafiltration effectively reduces total body water and improves postoperative hemodynamic and homeostatic functions. Venovenous modified ultrafiltration is a modification of this technique, which has the potentially added advantage of eliminating the obligatory left-to-right shunt associated with arteriovenous modified ultrafiltration. We tested the hypothesis that venovenous modified ultrafiltration is a safe and effective method of achieving ultrafiltration in children after cardiopulmonary bypass. METHODS: Thirty-eight pediatric patients were randomly assigned to undergo conventional, venovenous (n = 13), or no ultrafiltration venovenous (n = 13), and controls (n = 12). Perioperative, cardiopulmonary, and cytokine (tumor necrosis factor-alpha, interleukin-1beta, interleukin-6, interleukin-8, and interleukin-10) data were collected for statistical analysis. RESULTS: Compared with patients in the conventional ultrafiltration and control groups, patients undergoing venovenous modified ultrafiltration had the greatest volume of ultrafiltrate removed (46. 9 +/- 8.4 mL/kg vs 20.1 +/- 5.0 mL/kg and 0 mL/kg for conventional ultrafiltration and control groups, respectively; P =.0001), least increase in total body water (1.91% +/- 1.49% vs 3.90% +/- 1.86% and 8.24% +/- 3.41%; P =.05), greatest rise in hematocrit (39.7% +/- 1. 7% vs 33.8% +/- 2.1% and 29.6% +/- 2.3%; P =.006), and shortest length of hospital stay (4.41 +/- 0.28 days vs 6.69 +/- 1.47 days and 8.38 +/- 1.11 days; P =.03, P =.03). CONCLUSIONS: Venovenous modified ultrafiltration is a safe and effective method of reducing the increase in total body water and duration of postoperative convalescence after cardiopulmonary bypass.

Cardiopulmonary Bypass↗
PubMed1998

Standard versus modified bio-electrical impedance analysis on reactance measurements.

The purpose of this investigation was to compare score consistency of the observed reactance measurements for total body composition bio-electrical impedance analysis (BIA), using standard and modified electrode placement procedures. Subjects were 80 military males (19-56 years) who volunteered from Elmendorf Air Force Base, Anchorage, Alaska. The RJL Systems Spectrum Lightweight Instrument was used. RJL's rules were followed for standard procedure, and the proximal electrode sites were changed for the modified procedure. The hand and foot proximal electrodes were placed in the center of the antecubital space and popliteal fossa, respectively. The study used a four-faceted crossed, random effects design. The object of measurement was person, and facets of generalization were day, occasion, and trial. Data were analyzed independently for each electrode placement procedure. The analysis revealed: 1) person contributed the largest source of systematic variance, as expected, and 2) person x day interaction accounted for the significant percentage of unwanted measurement error for both electrode placement procedures. The relative and absolute coefficients of the G-studies (80 persons x 2 days x 2 occasions x 3 trials) were 0.86 for standard and 0.83 for modified. The D-studies (111, 211, 311, and 511) revealed relative and absolute coefficients which ranged from 0.75 to 0.94 for standard, 0.67 to 0.91 for relative, and 0.67 to 0.90 absolute for modified. The G-coefficients (G study and D studies) for reactance measurements showed the standard electrode placement procedure produced more consistent scores than the modified proximal electrode placement procedure. In conclusion, generalizability analysis on reactance scores demonstrated the standard electrode placement procedure still to be superior over the modified electrode placement procedure.

Adolescent↗
PubMed1999

Parent-child mediated learning interactions as determinants of cognitive modifiability: recent research and future directions.

The main objectives of this article are to describe the effects of mediated learning experience (MLE) strategies in mother-child interactions on the child's cognitive modifiability, the effects of distal factors (e.g., socioeconomic status, mother's intelligence, child's personality) on MLE interactions, and the effects of situational variables on MLE processes. Methodological aspects of measurement of MLE interactions and of cognitive modifiability, using a dynamic assessment approach, are discussed. Studies with infants showed that the quality of mother-infant MLE interactions predict later cognitive functioning and that MLE patterns and children's cognitive performance change as a result of intervention programs. Studies with preschool and school-aged children showed that MLE interactions predict cognitive modifiability and that distal factors predict MLE interactions but not the child's cognitive modifiability. The child's cognitive modifiability was predicted by MLE interactions in a structured but not in a free-play situation. Mediation for transcendence (e.g., teaching rules and generalizations) appeared to be the strongest predictor of children's cognitive modifiability. Discussion of future research includes the consideration of a holistic transactional approach, which refers to MLE processes, personality, and motivational-affective factors, the cultural context of mediation, perception of the whole family as a mediational unit, and the "mediational normative scripts."

Child↗
PubMed1999

Cervical Papanicolaou smear abnormalities in inner city Bronx adolescents: prevalence, progression, and immune modifiers.

BACKGROUND: The aim of this study was to quantify the prevalence of cervical smear abnormalities in sexually active adolescents and identify the effect of immune-modifying conditions. METHODS: Two hundred seventy-one females ages 13-22 years attending a clinic for sexually transmitted disease (STD) evaluation had cervical Papanicoloau (Pap) smears and completed sexual history questionnaires. Results of all follow-up Pap smears were obtained. Medical charts were available for 54 patients with cytologic follow-up and were reviewed for the presence of immune-modifying conditions. Follow-up smear results for patients with and without immune-modifying conditions were compared. Abnormality rates for all cervical smears seen in 1995 at Montefiore Medical Center were also obtained. RESULTS: The smear abnormality rate for adolescents was 20. 7% (abnormal squamous cells of undetermined significance [ASCUS], 12. 2%; low grade squamous intraepithelial lesion [LGSIL], 7.7%; high grade squamous intraepithelial lesion [HGSIL], 0.7%) compared with all adult females, for whom the rate was 13.2% (ASCUS, 9.9%; LGSIL, 2.5%; HGSIL, 0.6%; carcinoma 0.2%) (P < 0.0002). Of 20 initial ASCUS patients, 6 (30%) showed LGSIL or HGSIL on follow-up. Chart review allowed the clinical immune status of 54 patients to be determined. Of 14 patients with an immune-modifying condition (9 HIV positive patients, 3 receiving oral steroids, 1 liver transplant patient receiving steroids, and 1 with intestinal lymphangiectasia), 11 (78. 6%) developed or maintained an abnormality on cytologic follow-up. Of 40 patients with no identifiable immune-modifying condition, 11 (27.5%) developed or maintained an abnormality on cytologic follow-up (P < 0.00082). CONCLUSIONS: Sexually active adolescents are at higher risk of developing a significant cervical smear abnormality, especially LGSIL. Patients with an atypical Pap smear or immune-modifying condition require more attentive gynecologic monitoring. Cancer (Cancer Cytopathol)

Adolescent↗
PubMed1999

Enhanced antitumor immune responses of IL-2 gene-modified tumor vaccine by combination with IL-1 and low dose cyclophosphamide.

To enhance the antitumor immunity induced by IL-2 gene-modified tumor vaccine, we proposed a combined protocol to treat tumor-bearing mice using IL-2 gene-modified tumor vaccine in combination with IL-1 and low-dose Cyclophosphamide(Cy). After treatment with IL-2 gene-modified B16 melanoma cell vaccine alone, the pulmonary metastases of tumor-bearing mice were reduced and their survival time was prolonged. The anti-metastases effect was improved when the vaccine was used in combination with IL-1 or low-dose Cy. The best therapeutic effect was achieved when the IL-2 gene-modified vaccine was combined with IL-1 and low-dose Cy. The cytotoxicity of the splenic CTL, NK, and the levels of IL-2, TNF secreted by splenocytes increased after tumor-bearing mice were treated with the IL-2 gene-modified tumor vaccine. The above antitumor immune functions were augmented more significantly when IL-1, low-dose Cy were used in combination with IL-2 genemodified tumor vaccine. These results demonstrated that the IL-2 gene modified vaccine could exert more potent anti-metastases effects when it is combined with IL-1 or/and low-dose Cy by activating the specific and non-specific antitumor immune responses more effectively.

Animals↗
PubMed1999

Process stability assessed by selecting Shewhart's psi statistical analysis technique of the influence of matrix modifier and furnace program in the optimization and precision of zinc determinations by graphite furnace atomic absorption spectroscopy.

The method previously used in the Toxicology Laboratories of King Faisal Specialist Hospital and Research Center for determining the zinc concentration in serum by Zeeman atomic absorption spectrometer was improved by modifying the matrix modifier and by changing the heated graphite furnace atomization (HGA) program. After trying several methods we failed to achieve the required precision and the accuracy of methods for serum zinc determination. We changed the matrix modifier to a fifty percent mixture (v/v) of 3.90 grams per liter of ammonium phosphate in Type 1 water with 0.2% nitric acid and 1.0 gram per liter of magnesium nitrate in acidic water (0.2% HNO3) with 0.1% triton X-100 was used as matrix modifier. A twenty-five fold dilution of the sample in matrix modifier was injected on the L'vov's platform of the furnace. In order to reduce the high sensitivity of Zn the furnace program was modified. The method is found very robust. The average reproducibility between inter-runs and intra-run is less than 1.59% with a high degree of accuracy. We used two levels of controls i.e. normal or low level and abnormal or high level. The linearity and the detection limit of the assay were 0.9992 and 0.010 micromol/L respectively. Average recovery of the analyte was 98.65%. The X-Bar and R charts were constructed by using Shewhart's statistical analysis technique to assess the test methodology. It was found that the assay is capable and stable for routine clinical and research analysis. The capability index (C(P)) of the assay, an indicator of the precision, was calculated.

Data Interpretation, Statistical↗
PubMed1999

Modified alpha wrap techniques for dynamic urethral graciloplasty in an animal model.

Urethral sphincter reconstruction with a stimulated skeletal muscle flap has been used for treatment of severe intrinsic sphincter deficiency. Urethral strictures and failures were reported in some of the initial experiences. The etiology of these problems is not known, but elevated resting urethral pressures and excessive urethral displacement with stimulation are possible causes. We modified two operative techniques in forming dynamic urinary graciloplasty (DUG) in an attempt to minimize resting urethral pressure without stimulation and urethral mobility during stimulation. Two types of DUG were used. In the first group, a small flap (partial muscle wrap) from the gracilis muscle with an attachment site on the muscle was constructed in four dogs. In the second group, three dogs with a modified alpha wrap and proximal attachments were used. All of the gracilis muscle wraps were stimulated using an implanted programmable pulse stimulator with electrodes attached over the motor nerve. Following a 2-week, postrecovery period, urethral pressure measurements were obtained with and without stimulation. Five weeks were used for stimulation to condition the muscle. This was followed by 4 weeks of continuous stimulation. Thus, devices were implanted for 11 weeks. Before conditioning of the muscles was initiated, the partial muscle wrap pressure at rest was 42 +/- 27 cm H2O, which was higher than the incomplete alpha wrap resting pressure of 20 +/- 4 cm H2O. Stimulated partial flap pressure was 161 +/- 50 cm H2O, and stimulated modified alpha wrap pressures was 71 +/- 27 cm H2O. After conditioning with the modified alpha wrap, the resting and stimulated pressures were unchanged from before conditioning. Technical problems precluded collection of data during the conditioning period in dogs with partial flaps. During stimulation, the partial muscle wrap demonstrated marked deviation, whereas the modified alpha wrap had minimal urethral movement. Postmortem evaluation indicated no urethral stricture or fistula formation with either of the two types of wraps. The modified alpha wrap had several positive features. Advantages over the partial wrap were minimal resting pressures, reduced urethral mobility, and adequate sustained pressures during stimulation. Therefore, in contrast to the partial gracilis muscle wrap, aspects of the incomplete alpha wrap should be considered further for DUG.

Animals↗
PubMed2000

Long-term in vivo survival of receptor-modified syngeneic T cells in patients with human immunodeficiency virus infection.

To study human immunodeficiency virus (HIV)-specific cellular immunity in vivo, we transferred syngeneic lymphocytes after ex vivo expansion and transduction with a chimeric receptor gene (CD4/CD3-zeta) between identical twins discordant for HIV infection. Single and multiple infusions of 10(10) genetically modified CD8(+) T cells resulted in peak fractions in the circulation of approximately 10(4) to 10(5) modified cells/10(6) mononuclear cells at 24 to 48 hours, followed by 2- to 3-log declines by 8 weeks. In an effort to provide longer high-level persistence of the transferred cells and possibly enhance anti-HIV activity, we administered a second series of infusions in which both CD4(+ )and CD8(+) T cells were engineered to express the chimeric receptor and were costimulated ex vivo with beads coated with anti-CD3 and anti-CD28. Sustained fractions of approximately 10(3) to 10(4) modified cells/10(6) total CD4(+) or CD8(+) cells persisted for at least 1 year. Assessment of in vivo trafficking of the transferred cells by lymphoid tissue biopsies revealed the presence of modified cells in proportions equivalent to or below those in the circulation. The cell infusions were well tolerated and were not associated with substantive immunologic or virologic changes. Thus, adoptive transfer of genetically modified HIV-antigen-specific T cells was safe. Sustained survival in the circulation was achieved when modified CD4(+ )and CD8(+) T cells were infused together after ex vivo costimulation, indicating the important role played by antigen-specific CD4(+) T cells in providing "help" to cytotoxic effectors. (Blood. 2000;96:467-474)

Adult↗
PubMed2000

Clarifying selected CPT modifiers.

This discussion includes only 20 percent of the modifiers available for physician reporting, but could account for 80 percent of modifiers assigned for physician services. Modifier -91 was the only new modifier introduced in CPT 2000 and it is used to report a repeat clinical diagnostic laboratory test. It is not to be used when confirming initial results or for any other reason other than a clinical need to repeat the test for the same patient on the same day. Success with CPT modifier reporting requires a thorough review of CPT guidelines and some detective work for identifying health plan requirements for modified codes.

Abstracting and Indexing↗
PubMed2001

Absolute bioavailability of 2'-O-(2-methoxyethyl)-modified antisense oligonucleotides following intraduodenal instillation in rats.

Three modified 20-mer antisense oligonucleotides targeted to human intercellular adhesion molecule-1 mRNA were characterized for their presystemic stability and oral bioavailability compared with a first-generation phosphorothioate oligodeoxynucleotide (PS ODN), ISIS 2302. The three modified oligonucleotides contained 2'-O-(2-methoxyethyl) (2'-O-MOE) ribose sugar modifications on a portion, or on all of the nucleotides in the antisense sequence. In vitro metabolism studies conducted in various gastrointestinal and digestive tissue preparations indicated substantial improvement in stability of 2'-O-MOE-modified oligonucleotides. In addition, in vivo presystemic stability of these oligonucleotides was monitored in rats following intraduodenal administration. By 8 h after administration, only chain-shortened metabolites of the PS ODN were recovered in the gastrointestinal contents. In contrast, approximately 50% of the 2'-O-MOE ribose-modified (partial) compound remained intact (20-mer) by 8 h following administration. Both of the fully modified compounds (2'-O-MOE PO and PS) were completely stable with no measurable metabolites observed within 8 h of administration. The rank order of bioavailability was ISIS 11159 (full PS, full MOE) < ISIS 2302 (PS ODN) < ISIS 16952 (full PO, full MOE) < ISIS 14725 (full PS, partial MOE); the absolute plasma concentration bioavailability was measured in reference to intravenous dosing in the rat and was estimated at 0.3, 1.2, 2.1, and 5.5%, respectively. The optimal oligonucleotide chemistry for improved permeability and resulting bioavailability was the partially modified 3' hemimer 2'-O-MOE phosphorothioate oligonucleotide (ISIS 14725). Improved presystemic stability coupled with improved permeability were likely responsible for the remarkable improvement in the oral bioavailability of this compound.

Animals↗
PubMed2000

Resin-modified glass-ionomer restorations and in vitro secondary caries formation in coronal enamel.

OBJECTIVE: The purpose of this laboratory study was to compare the effects of a resin-modified glass ionomer and a resin composite restorative material on secondary caries formation in coronal enamel. METHOD AND MATERIALS: Twelve caries-free molars were sectioned into tooth quarters. Coronal cavities were prepared and then restored with either a resin-modified glass-ionomer material (mesiobuccal and mesiolingual tooth quarters), or a resin composite (distobuccal and distolingual tooth quarters). Caries like lesions were created, and secondary caries was examined by polarized light microscopy following lesion initiation and progression periods. RESULTS: The resin-modified glass-ionomer specimens had significantly shallower primary surface lesions at both the lesion initiation (35% shallower) and progression (45% shallower) periods than did the resin composite specimens. There were significantly fewer wall lesions (3-fold and 2-fold fewer following lesion initiation and progression, respectively) in the resin-modified glass-ionomer group than in the resin composite group. CONCLUSION: Resin-modified glass-ionomer restorations reduce the susceptibility of unrestored adjacent enamel surfaces and cavosurfaces to a constant cariogenic challenge. The caries resistance imparted to the surface enamel and cavosurface is most likely due to the fluoride release from the resin-modified glass-ionomer material.

Composite Resins↗
PubMed2000

Enamel wear of modified porcelains.

PURPOSE: To evaluate the wear of three different modified ceramics along with a conventional porcelain and the wear of opposing enamel at initial wear cycle on a two-body and a three-body wear simulation. MATERIALS AND METHODS: Modified ceramics used in this study included a low fusing/low crystal porcelain (Finesse), a high fusing/low crystal porcelain (Softspar), and a heat-pressable ceramic (IPS Empress). A conventional porcelain (Ceramco II) was used as the control material. Hemispherical shaped ceramic styli (1/8 inch in diameter) made of respective materials were fabricated according to the manufacturers' directions. Proximal surfaces of non-carious human molars were ground flat within the enamel with a silicon carbide paper to 600 grit with copious irrigation. They were perpendicularly opposed to each other with or without intermediate material as a food bolus and subjected to in vitro wear test by a UAB wear simulator. A 75.6 N load was applied vertically onto the surface at 1.2 Hz. The surface was duplicated after respective wear cycles. Seven specimens were tested for each group of both simulations. RESULTS: The enamel wear loss when opposing the modified ceramics was less than the Ceramco II control which exhibited the greatest values. The IPS Empress material showed the least amount of wear among them. Statistically significant differences were seen between the IPS Empress and the Ceramco II for every cycle interval evaluated (ANOVA, P < 0.05). Although the enamel wear loss when opposing the IPS Empress was significantly less (ANOVA, P < 0.05) than the others until 20,000 wear cycles, no significant differences were found among the modified ceramics at the end of 50,000 wear cycles. The concentric wear patterns were already prominent at 5,000 wear cycles on two-body wear, however, the wear facet of the three-body wear was smaller (the wear depth of 0-5 microm) than the two-body wear test, as it was quite similar to the one of the two-body wear test at 100 wear cycles. On the other hand, although no statistically significant differences were found among the three modified ceramics and between the conventional porcelain and the modified ceramics at every wear cycle, the high values of the Finesse since 10,000 wear cycles were probably due to the mechanical properties of this porcelain. Moreover, on the surface of the ceramic styli at the end of 50,000 wear cycles, the glaze layer on the contact area had not yet worn off.

Aluminum Silicates↗
PubMed2001

Modified cold storage of rat livers with self-made HYD solution.

OBJECTIVE: To investigate the cold preservation effect on rat livers of a modified storage method with self-made HYD solution. METHODS: The vascular bed of rat livers was expanded with an additional 20 to 40 ml self-made HYD solution/100 g liver. After resection of the liver, the extra HYD solution (expressed as % liver weight) was entrapped via portal infusion by tying off the supra- and infra-hepatic inferior vena cava. Forty rats were randomly divided into four groups including control group with conventional storage method, and 20%, 30% and 40% groups according to the amount of extra HYD solution. We compared the preservation effect of the modified storage method with that of the conventional storage method using an isolated perfused rat liver model. RESULTS: Bile production and all the indices of hepatic microcirculation including portal perfusion pressure, endothelin-1 in the effluent, trypan blue distribution time and histology were significantly superior in the modified method groups compared to those in the control group (P < 0.05). The contents of dihydroxybenzoic acid (DHBA) in the modified method groups were significantly lower than those in the control group (P < 0.05). Liver enzymes activities in the 30% group were markedly lower than those in the control group (P < 0.05). The preservation effect on rat liver in the 30% group was the best among the modified method groups. CONCLUSION: The modified cold storage method is effective and may have potential for clinical application in liver preservation.

Alanine Transaminase↗
PubMed2002

Delivery of a non-potassium modified maintenance solution to enhance myocardial protection in stressed neonatal hearts: a new approach.

OBJECTIVES: This study was undertaken to compare conventional cardioplegic strategies with a new approach that uses a modified non-potassium maintenance solution between cardioplegia doses in stressed neonatal hearts. METHODS: Thirty-five neonatal piglets underwent 60 minutes of ventilator hypoxia (inspired oxygen fraction 8%-10%) followed by 20 minutes of ischemia on cardiopulmonary bypass. In 10 animals bypass was discontinued without further ischemia (stress control group). The other 25 received a warm blood cardioplegic induction and were separated into 5 groups. In 5 animals cardiopulmonary bypass was discontinued without further ischemia (cardioplegia control group); the remaining 20 underwent an additional 70 minutes of cold blood cardioplegic arrest. Five received only intermittent cardioplegia every 20 minutes, whereas 15 also received cold blood maintenance infusions between cardioplegic doses (integrated strategy). In 5 of these animals the blood was unmodified, whereas in 10 a modified non-potassium "cardioplegia-like" solution was delivered either antegradely (n = 5) or retrogradely (n = 5). Myocardial function was assessed by pressure-volume loops (expressed as percentage of control); vascular function was assessed by coronary vascular resistance. RESULTS: All piglets that underwent hypoxic ischemic stress alone (controls) died. Warm induction alone (cardioplegic controls) partially repaired the stress injury. Intermittent cardioplegia preserved the depressed systolic function (end-systolic elastance 40% vs 39%), increased diastolic stiffness (255% vs 239%), reduced adenosine triphosphate (10.6 vs 12.2 microg/g tissue), and elevated coronary vascular resistance at levels identical to warm induction alone; infusing unmodified blood between cardioplegia doses (standard integrated) improved results slightly. In contrast, infusion of a cold modified solution (antegrade or retrograde) between cardioplegia doses (modified integrated) completely restored systolic function (end-systolic elastance 100% and 97%, P <.001 vs intermittent and standard integrated), only minimally increased diastolic stiffness (159% and 156%, P <.001 vs intermittent and standard integrated), restored adenosine triphosphate (18.8 and 16.6 microg/g, P <.001 vs intermittent and standard integrated), and normalized coronary vascular resistance (P <.001 vs intermittent and standard integrated). This strategy was used in 72 consecutive hypoxic patients (21 arterial switch operations, retrograde; 51 Fontan procedures, antegrade) with a 2.8% mortality. CONCLUSIONS: Infusion of a cold modified solution between cardioplegic doses (modified integrated protection) significantly improved myocardial protection in the stressed neonatal heart, was effective delivered either antegradely or retrogradely, and was used successfully for hypoxic (stressed) pediatric patients.

Adenosine Diphosphate↗
PubMed2000

[An experimental study on F-heparin surface modified IOLs implanted into the Rhesus monkeys' eyes].

OBJECTIVE: To evaluate the biocompatibility of F-heparin surface modified IOLs. METHODS: 13 monkeys were divided into 3 groups, and implanted with different surface modified and non-modified IOLs into their eyes. All of the eyes were examined by slitlamp microscope and Schiötz tonometer at postoperative 15, 30, 60, 90 and 180 days. Postoperatively, at different periods the aqueous was aspirated from the anterior chamber to calculate cells. RESULTS: F-heparin surface modified IOLs induced milder inflammatory reaction and less dense posterior capsula opacification (PCO) than non-modified IOLs. CONCLUSION: F-heparin surface modified IOL has a better biocompatibility.

Animals↗
PubMed2002

[Stability of HDTMA modified montmorillonite].

In order to probe the stability of organic montmorillonite, the nature montmorillonite was modified with hexadeeyltrimethylammonium (HDTMA) in different cation exchange capacity (CEC). The results of experiments showed that the stability of modified montmorillonite declined as its CEC was big and HDTMA was desorbed from 1.0 CEC modified montmorillonite. HDTMA bound to the montmorillonite surface was resistant to temperature(70 degrees C) and instable to strong ultrasonic and to vibrational intensity(180 r/min). The result also indicated that the stability of modified montmorillonite increased to NaCl(1.8 mol/L) but decreased to CaCl2 (1.8 mol/L) and modified montmorillonite was more stable in high-pH environment(12.00) than in low-pH environment(2.06). On the basis of the results of these studies, low CEC modified montmorillonite appeared suitable as a sorbent for wastewater chemical treatment and as carrier for wastewater biotreatment in low stir environment.

Bentonite↗