Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 18 de 18
Filter
1.
Luminescence ; 32(1): 71-77, 2017 Feb.
Article in English | MEDLINE | ID: mdl-27121418

ABSTRACT

In this work we synthesized SrO-ZnO-P2 O5 glasses mixed with Pb3 O4 (heavy metal oxide) and doped with different amounts of Dy2 O3 (0.1 to 1.0 mol%). Subsequently their emission and decay characteristics were investigated as a function of Dy2 O3 concentration. The emission spectra exhibited three principal emission bands in the visible region corresponding to 4 F9/2  â†’ 6 H15/2 (482 nm), 6 H13/2 (574 nm) and 6 H11/2 (663 nm) transitions. With increase in the concentration of Dy2 O3 (upto 0.8 mol%) a considerable increase in the intensity of these bands was observed and, for further increase, quenching of photoluminescence (PL) output was observed. Using emission spectra, various radiative parameters were evaluated and all these parameters were found to increase with increase in Dy2 O3 concentration. The Y/B integral emission intensity ratio of Dy3+ ions evaluated from these spectra exhibited a decreasing trend with increase in the Dy2 O3 concentration up to 0.8 mol%. Quenching of luminescence observed in the case of the glasses doped with 1.0 mol% is attributed to clustering of Dy3+ ions. The quantitative analysis of these results together with infra-red (IR) spectral studies indicated that 0.8 mol% is the optimum concentration of Dy3+ ions needed to achieve maximum luminescence efficiency. Copyright © 2016 John Wiley & Sons, Ltd.


Subject(s)
Dysprosium/analysis , Dysprosium/chemistry , Glass/chemistry , Lead/chemistry , Luminescence , Phosphates/chemistry , Strontium/chemistry , Zinc Compounds/chemistry , Ions/analysis , Spectrophotometry, Infrared
2.
Am J Prev Med ; 45(6): 710-9, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24237912

ABSTRACT

BACKGROUND: In 2010, Philadelphia enacted a menu-labeling law requiring full-service restaurant chains to list values for calories, sodium, fat, and carbohydrates for each item on all printed menus. PURPOSE: The goal of the study was to determine whether purchase decisions at full-service restaurants varied depending on the presence of labeling. METHODS: In August 2011, this cross-sectional study collected 648 customer surveys and transaction receipts at seven restaurant outlets of one large full-service restaurant chain. Two outlets had menu labeling (case sites); five outlets did not (control sites). Outcomes included differences in calories and nutrients purchased and customers' reported use of nutrition information when ordering. Data were analyzed in 2012. RESULTS: Mean age was 37 years; 60% were female; 50% were black/African-American and reported incomes ≥$60,000. Customers purchased food with approximately 1600 kcal (food plus beverage, 1800 kcal); 3200 mg sodium; and 35 g saturated fat. After adjustment for confounders, customers at labeled restaurants purchased food with 151 fewer kilocalories (95% CI=-270, -33); 224 mg less sodium (95% CI=-457, +8); and 3.7 g less saturated fat (95% CI=-7.4, -0.1) compared to customers at unlabeled restaurants (or 155 less kilocalories from food plus beverage, 95% CI=-284, -27). Those reporting that nutrition information affected their order purchased 400 fewer food calories, 370 mg less sodium, and 10 g less saturated fat. CONCLUSIONS: Mandatory menu labeling was associated with better food choices among a segment of the public dining at full-service restaurants. Consumer education on the availability and use of nutrition information may extend the impact of menu labeling.


Subject(s)
Choice Behavior , Food Labeling/legislation & jurisprudence , Restaurants/legislation & jurisprudence , Adolescent , Adult , Aged , Aged, 80 and over , Cross-Sectional Studies , Data Collection , Energy Intake , Female , Government Regulation , Humans , Male , Middle Aged , Nutritive Value , Philadelphia , Young Adult
3.
Indian J Endocrinol Metab ; 16(Suppl 2): S345-6, 2012 Dec.
Article in English | MEDLINE | ID: mdl-23565422

ABSTRACT

INTRODUCTION: It is known that dyslipidemia and increased insulin resistance were associated with overt hypothyroidism, but their association with subclinical hypothyroidism is conflicting. Aim was to evaluate insulin resistance and lipid alterations in subclinical hypothyroidism. METHODS: Fifty consecutive cases of subclinical hypothyroidism are the subjects of the study. The cases are compared with age, gender and BMI matched controls. Lipid profile, insulin levels, FPG are assessed after overnight fast. Insulin resistance is calculated using HOMA-IR. The correlation between TSH& lipid prolife, TSH & IR was assessed. RESULTS: Total cholesterol (169.37±32.83 vs. 154.5±18.71, p= 0.031) & low density lipoprotein cholesterol (105.76±26.92vs 93.80±16.67, p=0.037) were significantly higher in cases compared to controls. High density lipoprotein cholesterol (44.23±4.65 vs 42.26±3.20, p=0.0507) was lower in cases which showed a trend towards significance. Triglycerides (97.64±39.44 vs. 92.96±43.49,p=0.65) , fasting insulin levels (11.74±7.16 vs 9.77±5.54,p=0.211) and Insulin resistance (2.30±1.49 vs. 1.78±1.09, p=0.11) were elevated but did not differ significantly between the two groups. CONCLUSION: Subclinical hypothyroidism is associated with elevation of TC, LDL-C and non significant increase in TG and insulin resistance. Both lipid profile and insulin resistance did not correlate with severity of hypothyroidism.

4.
Burns ; 25(5): 415-23, 1999 Aug.
Article in English | MEDLINE | ID: mdl-10439150

ABSTRACT

The leading cause of morbidity and mortality in severe burn wound patients is infection. Treatment of burn wound infection is complicated by the emergence of antibiotic resistant organisms. A potential therapeutic alternative to antibiotic drugs is the local administration of polyclonal antibodies, termed passive local immunotherapy (PLI), directly to the burned tissue. A mouse burn wound infection model to simulate full thickness burn wound infection was used to evaluate the efficacy of passive local immunotherapy as a viable prophylactic or therapeutic agent. Pooled human immunoglobulins (IgG), delivered locally to the site of infection, are shown to be more effective at preventing fatal burn wound sepsis than treatment by intravenous infusion of IgG. A single 10 mg dose of human IgG administered locally to the burned, infected tissue site, either 24 hours prior to bacterial challenge, or within 3 hours after bacterial challenge, enhanced animal survival significantly (P < 0.001 and P < 0.05 respectively) compared to control animals. In addition, reduced levels of bacteria were found in local and systemic tissues of IgG-treated mice compared to control mice (P < 0.05). These data support the local use of polyclonal immunoglobulin preparations as an efficacious and cost effective means to prevent and treat burn wound infections.


Subject(s)
Burns/complications , Immunoglobulin G/therapeutic use , Pseudomonas Infections/therapy , Wound Infection/therapy , Animals , Female , Immunization, Passive , Immunoglobulins, Intravenous/administration & dosage , Injections, Intravenous , Injections, Subcutaneous , Mice , Pseudomonas Infections/microbiology , Pseudomonas Infections/mortality , Pseudomonas aeruginosa/growth & development , Survival Rate , Wound Infection/microbiology
5.
J Biomed Mater Res ; 29(10): 1179-83, 1995 Oct.
Article in English | MEDLINE | ID: mdl-8557719

ABSTRACT

The effect of poly(methyl methacrylate) (PMMA), titanium alloy, and silicone discs on the capacity of rabbit alveolar macrophages (AM) to kill RP12 strain of Staphylococcus epidermidis (RP12) was studied in vitro. When freshly harvested AM were preincubated with PMMA discs for 3 h and subsequently assayed for RP12 killing, there was no change in the RP12 killing capacity of AM. However, when AM were incubated with PMMA discs for 6 or 18 h at 37 degrees C in 5% CO2, the RP12 killing capacity of AM was reduced to 15% and 4%, respectively. Preincubation of AM with titanium alloy for 6 h reduced RP12 killing capacity of AM to 30%, and to 21% in 18-h incubation. Silicone discs did not affect the RP12 killing by AM at 6 h of preincubation, but reduced RP12 killing (35%) by AM when preincubated for 18 h. Preincubation of AM with PMMA discs for 3 or 6 h did not affect the level of PMA-elicited oxidative burst of AM as measured by a luminol-enhanced chemiluminescent assay. Superoxide dismutase, which eliminated the oxidative burst of AM by 90%, did not affect the RP12 killing by AM.


Subject(s)
Biocompatible Materials/toxicity , Macrophages, Alveolar/drug effects , Macrophages, Alveolar/immunology , Phagocytosis/drug effects , Staphylococcus epidermidis , Animals , In Vitro Techniques , Luminescent Measurements , Methylmethacrylates/toxicity , Rabbits , Respiratory Burst/drug effects , Silicones/toxicity , Superoxide Dismutase/pharmacology , Titanium/toxicity
6.
J Biomed Mater Res ; 29(1): 101-5, 1995 Jan.
Article in English | MEDLINE | ID: mdl-7713948

ABSTRACT

A simple technique was developed to prepare phagocytosable-size particles from the silicone gel used in breast implants. Sonication of silicone gel (1 g) in 5 ml of 20 mM sodium phosphate buffer (pH 7.2) containing 1% (wt/vol) polyoxypropylene-polyethylene block surfactant (F-68 or F-108) produced silicone gel particles ranging from 1-50 microns in diameter. Passage of the suspension through a series of filters yielded phagocytosable particles (1-5 microns in diameter) at a concentration of ca. 2 x 10(9) particles/ml. The particles remained as individual particles, did not coalesce to form large clumps, and were not pelleted by centrifugation (2000 x g, 20 min). They were not toxic for rabbit alveolar macrophages (AM) during 24 h of incubation at 37 degrees C, did not elicit an oxidative burst from AM in vitro in a luminol-enhanced chemiluminescent assay, and did not significantly increase the phorbol myristate acetate (PMA)-elicited oxidative burst by AM. AM isolated from rabbits 2 days after the intravenous injection of silicone particles were not primed or activated (i.e., the AM did not show an enhanced oxidative burst when elicited with PMA in vitro). However, AM isolated from rabbits 2 days after intratracheal injection of the particles were primed but only exhibited a 4-6-fold increase in the oxidative burst elicited with PMA.


Subject(s)
Macrophages, Alveolar/metabolism , Silicones/chemical synthesis , Animals , Breast Implants/adverse effects , Female , Gels , In Vitro Techniques , Luminescent Measurements , Macrophages, Alveolar/drug effects , Male , Oxidation-Reduction , Particle Size , Phagocytosis/drug effects , Rabbits , Reactive Oxygen Species/metabolism , Respiratory Burst , Silicones/pharmacology , Tetradecanoylphorbol Acetate/pharmacology
7.
J Biomed Mater Res ; 28(11): 1289-94, 1994 Nov.
Article in English | MEDLINE | ID: mdl-7829558

ABSTRACT

Adherence of selected strains of coagulase-negative staphylococci to various biomaterials, and the inhibition of their adherence by extracellular slime obtained from the RP12 strain of Staphylococcus epidermidis were studied in vitro. S. epidermidis RP12 adhered considerably more to polymethylmethacrylate (PMMA) discs than did the SP2 strain of S. hominis and the SE-360 strain of S. hyicus. Strain RP12 was less adherent to titanium alloy, ultrahigh molecular weight polyethylene (UHMWPE), and Teflon discs than to PMMA discs. Exposure of PMMA discs to extracellular slime extracted from strain RP12 greatly reduced adherence of strain RP12, SP2, SE-360, and S. epidermidis RP-62A. The active component(s) was present in the > 10 kD mol wt fraction obtained by Amicon YM10 ultrafiltration of crude slime; heat treatment of the fraction did not affect its inhibitory activity. When the bacteria and RP12 slime fractions were added simultaneously to the PMMA discs, the > 10 kD mol wt fraction of slime competitively inhibited adherence of strain RP12 to PMMA discs; in contrast, the < 10 kD mol wt fraction enhanced adherence of strain RP12 to PMMA discs.


Subject(s)
Bacterial Adhesion/drug effects , Bacterial Capsules/pharmacology , Biocompatible Materials , Methylmethacrylates , Staphylococcus epidermidis/physiology , Titanium , Alloys , Bacterial Capsules/chemistry , Species Specificity , Staphylococcus epidermidis/chemistry , Temperature
8.
Semin Arthroplasty ; 5(4): 160-70, 1994 Oct.
Article in English | MEDLINE | ID: mdl-10155159

ABSTRACT

Biomaterial implants, traumatized tissues and bone are susceptible to immediate and delayed infections because microbes preferentially adhere to "inert biomaterials" or to damaged tissue surfaces. This type of infection is resistant to antibiotic therapy and most often requires removal of the prosthesis or infected tissue. This article discusses glycocalyx, biofilm, microbes, and resistant infection in prosthesis or infected tissue.


Subject(s)
Bacterial Adhesion , Bacterial Infections/physiopathology , Biocompatible Materials , Biofilms , Prosthesis-Related Infections , Humans , Prosthesis-Related Infections/microbiology , Prosthesis-Related Infections/physiopathology
9.
J Leukoc Biol ; 54(5): 439-43, 1993 Nov.
Article in English | MEDLINE | ID: mdl-8228622

ABSTRACT

A novel system for priming adult rabbit alveolar macrophages (AMs) in vivo for markedly enhanced oxidative responses is described. When adult rabbits were injected intravenously (i.v.) with 1- to 5-microns particles such as zymosan, latex particles, or heat-killed bacille Calmette-Guérin, AMs were primed in 1-3 days for greatly enhanced phorbol myristate acetate (PMA)- or opsonized zymosan (Op-zym)-elicited chemiluminescent (CL) responses. Intratracheal (i.t.) injection of zymosan particles also primed AMs for enhanced PMA- or Op-zym-elicited CL responses. AMs obtained from particle-injected rabbits showed up to 100-fold higher levels of PMA-elicited CL responses than AMs from normal rabbits. In contrast, Op-zym failed to prime normal AMs in vitro for enhanced CL responses. Whereas AMs could not be primed in vivo with an i.v. injection of particles of approximately 24 microns diameter. AMs could be primed if the particles were administered by the i.t. route. The priming appears to be independent of particle types. The priming effect was of short duration and declined after 5 to 7 days. The possibility that this system represents the primitive cellular immune response found in invertebrates is discussed. The potential use of this system as a means of immune augmentation prompts further investigation.


Subject(s)
Immunity, Cellular/immunology , Latex/pharmacology , Macrophages, Alveolar/cytology , Macrophages, Alveolar/metabolism , Mycobacterium bovis/physiology , Zymosan/pharmacology , Animals , Cells, Cultured , Female , Humans , Immune System/cytology , Immune System/metabolism , Immune System/physiology , Injections, Intravenous , Latex/administration & dosage , Luminescent Measurements , Macrophages, Alveolar/physiology , Male , Oxidation-Reduction , Rabbits , Tetradecanoylphorbol Acetate/pharmacology , Zymosan/administration & dosage
10.
Int J Artif Organs ; 16(11): 755-63, 1993 Nov.
Article in English | MEDLINE | ID: mdl-8150521

ABSTRACT

Biomaterials are being used with increasing frequency for tissue substitution. Complex devices such as total joint replacement and the total artificial heart represent combinations of polymers and metal alloys for system and organ replacement. The major barrier to the extended use of these devices is bacterial adhesion to biomaterials, which causes biomaterial-centered infection, and the lack of successful tissue integration or compatibility with biomaterial surfaces. Adhesion-mediated infections are extremely resistant to antibiotics and host defenses and frequently persist until the biomaterial or foreign body is removed. The pathogenesis of adhesive infections is related, in part, to preferential colonization of "inert" substrate whose surfaces are not integrated with healthy tissues composed of living cells and intact extracellular polymers. Tissue integration is an interesting parallel to microbial adhesion and is a desired phenomenon for the biocompatibility of certain implants and biomaterials. Tissue integration requires a form of eukaryocytic adhesion or compatibility with possible chemical integration to an implant surface. Many of the fundamental principles of interfacial science apply to both microbial adhesion and to tissue integration and are general to and independent of the substratum materials involved. Interactions of biomaterials with bacteria and tissue cells are directed not only by specific receptors and outer membrane molecules on the cell surface, but also by the atomic geometry and electronic state of the biomaterial surface. An understanding of these mechanisms is important to all fields of medicine and is derived from and relevant to studies in microbiology, biochemistry, and physics.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Bacterial Adhesion , Biocompatible Materials , Heart, Artificial/adverse effects , Heart-Assist Devices/adverse effects , Prosthesis-Related Infections/etiology , Alloys , Anti-Bacterial Agents/therapeutic use , Drug Resistance, Microbial , Female , Humans , Male , Polymers , Prosthesis-Related Infections/drug therapy , Surface Properties
11.
Biomaterials ; 14(8): 609-14, 1993 Jul.
Article in English | MEDLINE | ID: mdl-8399955

ABSTRACT

The effect of poly(methyl methacrylate) (PMMA) on the oxidative responses and antibacterial activity of adult rabbit alveolar macrophages (AM) was studied. PMMA beads (ca. 0.3 micron diameter) elicited an acute respiratory burst within 6-8 min after the addition of the beads. In contrast. Teflon beads of comparable size (ca. 0.2 micron diameter) did not elicit an oxidative burst of AM. An oxidative response was elicited only by those PMMA samples that had affinity for AM adherence. Incubation of AM with PMMA beads reduced the subsequent phorbol myristate acetate (PMA)-elicited oxidative burst by more than 80%. The Staphylococcus epidermidis--RP12 killing capacity of AM was greatly increased when PMMA beads (ca. 0.3 micron) were added to the challenge dose of bacteria. Pre-incubation of freshly harvested AM with PMMA beads, which greatly reduced subsequent PMA-elicited chemiluminescent (CL) responses did not significantly affect the RP12 killing capacity of AM. Our data also suggest that killing of the RP12 strain of S. epidermidis does not involve reactive oxygen intermediates.


Subject(s)
Macrophages, Alveolar/drug effects , Macrophages, Alveolar/physiology , Methylmethacrylates/pharmacology , Animals , Cell Adhesion/drug effects , Female , Macrophages, Alveolar/metabolism , Male , Oxidation-Reduction , Rabbits , Respiratory Burst/drug effects , Staphylococcus epidermidis/physiology , Surface-Active Agents/pharmacology
12.
J Leukoc Biol ; 51(4): 379-85, 1992 Apr.
Article in English | MEDLINE | ID: mdl-1564401

ABSTRACT

We investigated the effect of individual phospholipids contained in pulmonary surfactant (PS) on the macrophage-activating factor (MAF)-induced priming of rabbit alveolar macrophages (AMs) for oxidative responses elicited by phorbol myristate acetate (PMA) or opsonized zymosan (Op-Zym). AMs were incubated with MAF with or without phospholipids for 18 h. After incubation, oxidative responses were elicited with PMA (0.5 micrograms/ml) or Op-Zym (250 micrograms/ml) and monitored by chemiluminescence (CL) assays. The data indicate that natural surfactant inhibited MAF-induced priming of rabbit AMs for PMA- or Op-Zym-elicited oxidative responses. Artificial surfactant inhibited PMA-elicited CL responses but enhanced Op-Zym-elicited CL responses. Individual phospholipids differed in modulative activities. Dioleoyl phosphatidylcholine (DOPC), dipalmitoyl phosphatidylglycerol (DPPG), and phosphatidylinositol (PI) inhibited MAF-induced priming when the oxidative responses were elicited with PMA. Whereas DPPG inhibited Op-Zym-elicited oxidative responses, dipalmitoyl phosphatidylcholine (DPPC) and DOPC primed AMs for increased Op-Zym-elicited oxidative responses. DOPC did not affect the binding of phorbol dibutyrate to AMs, which suggests that reduced cell binding of phorbol ester was not responsible for the inhibition of PMA-elicited oxidative responses in AMs treated with DOPC. Similarly, DPPC, DOPC, and DPPG did not affect the number of zymosan particles phagocytosed by AMs compared to the control, which suggested that enhanced or reduced Op-Zym-elicited oxidative responses by phospholipids were not due to altered phagocytic activity of AMs. In conclusion, our data indicate that individual surfactant phospholipid differently modulates priming of AMs for oxidative responses, and the effect of individual phospholipids does not account for the effect of complete PS on priming of AMs.


Subject(s)
Macrophages, Alveolar/physiology , Phospholipids/pharmacology , Pulmonary Surfactants/physiology , Animals , Fatty Acids/pharmacology , Female , Glycerylphosphorylcholine/pharmacology , Macrophage-Activating Factors/pharmacology , Male , Phagocytosis/drug effects , Phorbol 12,13-Dibutyrate/pharmacology , Rabbits , Respiratory Burst/drug effects , Serum Albumin, Bovine/chemistry , Tetradecanoylphorbol Acetate/pharmacology , Zymosan/pharmacology
13.
J Leukoc Biol ; 49(5): 442-8, 1991 May.
Article in English | MEDLINE | ID: mdl-1849952

ABSTRACT

The effect of herpes simplex virus type 2 (HSV-2) infection on the oxidative response in infant and adult rabbit alveolar macrophages (AM) was studied using either phorbol myristate acetate (0.5 microgram PMA/ml) or latex (250 micrograms/ml) as eliciting agents in a chemiluminescence (CL) assay. Results indicated that uninfected infant AM responded to a latex-elicited but not PMA-elicited CL response. HSV-2 infection (moi = 1.0) of infant AM for 2 hr at 37 degrees C did not alter the PMA or latex-elicited CL responses. In contrast, uninfected adult AM exhibited a markedly increased CL response when elicited with either PMA or latex. HSV-2 infection (moi = 1) of adult AM for 2 hr further increased both PMA- and latex-elicited CL responses. Increasing the moi to 10 inhibited both PMA- and latex-elicited CL responses. Incubation of uninfected control and HSV-2 infected adult AM for 18 hr at 37 degrees C resulted in spontaneous priming of the cells for increased CL responses. In the absence of PMA HSV-2 alone failed to elicit a CL response in adult AM. Infection with heat-inactivated HSV-2 (moi = 1.0 before heat inactivation) did not prime adult AM for enhanced CL responses. AM from BCG immunized adult rabbit produced a considerably higher level CL response that nonimmunized AM; however, HSV-2 infection of these cells did not further enhance the response. In summary, these data indicate that adult AM but not infant AM can be primed by active HSV-2 infection for an increased CL response elicited by either PMA or latex.


Subject(s)
Cell Transformation, Viral , Macrophages/physiology , Oxygen Consumption , Simplexvirus/genetics , Animals , Cells, Cultured , Female , Kinetics , Luminescent Measurements , Luminol , Macrophages/drug effects , Macrophages/immunology , Male , Mycobacterium bovis/immunology , Rabbits , Tetradecanoylphorbol Acetate/pharmacology
14.
Asia Pac Popul J ; 1(2): 39-56, 1986 Jun.
Article in English | MEDLINE | ID: mdl-12340774

ABSTRACT

PIP: An experiment was conducted in 1983-84 in a district of Rajasthan State to verify the feasibility of developing and institutionalizing a planning system at the primary health center (PHC) level as a means of improving the performance of maternal and child health (MCH) and family planning service delivery. As a 1st step, an analysis of PHC performance was carried out in the selected district with the help of medical officers' responses to a questionnaire. Based on this analysis, 2 PHCs were selected for experimentation. The 2 differed in terms of environment and organization related factors and in terms of perceived constraints on performance as identified by the medical officers in charge of each. Different planning strategies appropriate to the particular configuration of factors affecting PHC performance were required. In this context 3 different foci were indicated: ensuring needed inputs, planning for workers' performance and activity planning based on clients' needs. The institutionalization of client-oriented planning systems in PHCs require the improvement of client record keeping, flexibility of PHC medical officers in providing required inputs as dictated by client needs, and organizational support from higher levels. Implementation of a planning system to systematize PHC operations requires commitment on the part of the state, district and PHC officials and their continuing involvement during implementation.^ieng


Subject(s)
Health Facilities , Health Personnel , Health Planning , Health Services Administration , Planning Techniques , Primary Health Care , Rural Health Services , Asia , Data Collection , Delivery of Health Care , Developing Countries , Goals , Health , Health Resources , Health Services , Health Services Needs and Demand , India , Organization and Administration
15.
Plant Physiol ; 78(1): 29-33, 1985 May.
Article in English | MEDLINE | ID: mdl-16664202

ABSTRACT

A study was made of the influence of wounding on the senescence of standard oat leaf segments in the dark. Wounding was by either subdividing the 3 centimeter long segments into 5 millimeter subsegments, gently scraping the adaxial surface of the segments with a sharp blade, making transverse linear cuts, or by making many small holes with a needle. Wounding considerably delayed the loss of both chlorophyll and protein in the dark and the amount of inhibition was roughly proportional to the intensity of wounding. With surface wounding, the inhibition of senescence was detectable from the first day of dark incubation; other methods caused moderate promotion of senescence for the first 2 days but decreased the loss of chlorophyll and protein thereafter. A number of senescence-modifying substances acted similarly on both unwounded and wounded segments, but the amount of chlorophyll and protein in the wounded segments was always more than in the respective controls. Cytokinins, however, provided an exception, since their effect was actually decreased by wounding. The proteases operating at pH 4.1 and 6.6 were both clearly less active in the wounded leaves than in controls. The possible mechanism of this inhibitory effect of wounding on senescence is discussed.

16.
J Natl Med Assoc ; 75(5): 503-7, 1983 May.
Article in English | MEDLINE | ID: mdl-6864830

ABSTRACT

The authors established the specificity, reliability, and precision of human erythrocyte insulin radioreceptor assay. On the basis of insulin binding, cell viability, and degree of hemolysis, heparin sodium was found to be a more suitable anticoagulant than sodium fluoride, ethylenediaminetetraacetic acid, sodium oxalate, or sodium citrate. In two sets of experiments carried out at 4°C and 23°C, human erythrocytes were stored as whole blood or isolated erythrocytes suspended in Tris-{4-(2-hydroxyethyl)-1-piperazine-ethanesulfonic acid} buffer. The effect of storage under these conditions was evaluated by erythrocytespecific insulin binding. Human erythrocytes can be stored for 72 hours at 4°C without any change in insulin binding, insulin receptor sites per cell, or average affinity constant at the empty sites. Isolated erythrocytes can also be stored in plasma for 72 hours or in buffer G for 24 hours at 4°C without any change in insulin binding. It is not advisable to store human erythrocytes in plasma or as whole blood for more than 24 hours at 23°. These findings are useful in preserving insulin receptor activity when storage of erythrocytes is unavoidable.


Subject(s)
Blood Preservation/methods , Erythrocytes/metabolism , Receptor, Insulin/metabolism , Anticoagulants/metabolism , Heparin/pharmacology , Humans , Radioligand Assay
17.
Clin Chem ; 28(12): 2421-2, 1982 Dec.
Article in English | MEDLINE | ID: mdl-7139924

ABSTRACT

Hematofluorometers manufactured by two different companies (Aviv Biomedical and Environmental Science Associates) performed satisfactorily for protoporphyrin determinations with proficiency test samples but showed about a 30% low bias with actual clinical blood specimens.


Subject(s)
Erythrocytes/analysis , Lead Poisoning/blood , Porphyrins/blood , Porphyrins/standards , Protoporphyrins/blood , Protoporphyrins/standards , Child , False Negative Reactions , Fluorometry/instrumentation , Humans , Methods , Quality Control , Reference Standards , Toxicology
18.
Clin Chem ; 22(2): 221-3, 1976 Feb.
Article in English | MEDLINE | ID: mdl-1248123

ABSTRACT

We describe a rapid microscale procedure for blood lead determination by anodic stripping voltammetry. Results correlate well with those obtained by atomic absorption spectroscopy. The procedure involves use of a metal-exchange reagent, which rapidly releases bound lead from its macromolecular binding sites, thus eliminating a long and cumbersome perchloric acid digestion procedure. Reproducibility and analytical recovery of added lead were both excellent. Our results show that anodic stripping voltammetry is a reliable, sensitive micromethod for routine determination of blood lead.


Subject(s)
Lead/blood , Binding Sites , Evaluation Studies as Topic , Humans , Macromolecular Substances , Mass Screening , Microchemistry , Potentiometry , Quality Control , Spectrophotometry, Atomic
SELECTION OF CITATIONS
SEARCH DETAIL
...