Development of a novel method to measure material surface staining by cigarette, e-cigarette or tobacco heating product aerosols

Tobacco smoke (CS) may visually stain indoor surfaces including ceilings, walls and soft furnishings over time. Potentially reduced risk products (PRRPs) such as e-cigarettes (EC) and tobacco heating products (THP) produce chemically less complex aerosols with significantly reduced levels of toxicants, particles and odour. However, the potential effects of EC and THP aerosols on the staining of indoor surfaces are currently unknown. In this study, an exposure chamber was developed as a model system to enable the accelerated staining of wallpaper and cotton samples by a scientific reference cigarette (3R4F), three THP (glo™, glo™ pro, glo™ sens) and an e-cigarette (iSwitch Maxx).

Exposure to 3R4F reference cigarettes caused the greatest level of staining, which was significantly higher than glo™, glo™ pro, glo™ sens or iSwitch Maxx aerosols, all of which showed relatively little colour change. Exposure to 200–1000 puffs of 3R4F cigarette smoke resulted in a visible dose response effect to wallpaper and cotton samples which was not observed following exposure to glo™, glo™ pro, glo™ sens or iSwitch Maxx aerosols. Aging of the samples for 4 weeks post-exposure resulted in changes to the staining levels, however PRRP staining levels were minimal and significantly lower than 3R4F exposed samples.

For the first time, diverse PRRPs across the tobacco and nicotine products risk continuum have been assessed in vitro for their impact on surface staining. CS exposure significantly increased the level of wallpaper and cotton staining, whereas exposure to glo™, glo™ pro, glo™ sens or iSwitch Maxx aerosols resulted in significantly reduced levels of staining, staining levels were also comparable to untreated control samples.

Knotted Femoral Nerve Catheter

We describe a case of knotting of a femoral nerve catheter which prevented removal by traction after knee replacement surgery. In this context, early surgical removal should be performed as bacterial colonization of femoral catheters is common. Radiological imaging of the catheter may assist decision-making about whether to persist with traction and what surgical approach is required. Minimizing the length of catheter inserted to less than 10 cm makes knotting unlikely, but will decrease the chance of achieving lumbar plexus blockade which could improve analgesia if the catheter passes centrally.

Assessment of enamel discoloration in vitro following exposure to cigarette smoke and emissions from novel vapor and tobacco heating products

PURPOSE

To evaluate in vitro enamel sample discoloration following exposure to a scientific reference cigarette (3R4F) or emissions from next generation tobacco and nicotine products (NGPs) such as electronic cigarettes (EC) and tobacco heating products (THP).

METHODS

Bovine enamel blocks (6.5 × 6.5 mm) were prepared and pre-incubated with human or artificial saliva, to form a pellicle layer before exposure to either particulate matter (PM) or whole aerosols. PM was prepared by capturing 3R4F cigarette smoke (CS), a commercial THP (THP1.0) or a novel vapor product (NVP)/next generation e-cigarette aerosols on Cambridge filter pads followed by elution with dimethyl sulfoxide (DMSO). Ten enamel samples were exposed to each PM for 14 days. For aerosol exposure, 12 enamel samples were exposed (200 puffs per day, for 5 consecutive days) to 3R4F CS or THP1.0 and NVP aerosols. Control samples were incubated with DMSO (PM study) or phosphate buffered saline (PBS, aerosol study). Individual enamel sample color readings (L*, a*, b*) were measured at baseline and on each exposure day. Mean ΔL*, Δa*, Δb* and ΔE values were calculated for each product or control. A one-way ANOVA was used to assess the differences between the products and controls. The Tukey procedure for pairwise comparisons was also used.

RESULTS

At all timepoints, 3R4F PM and CS induced enamel discoloration that was statistically significant (< 0.0001) when compared to THP1.0 or NVP. After 14-day PM exposure, mean ΔE values were 29.4± 3.6, 10.5 ± 2.3, 10.7 ± 2.6 and 12.6 ± 2.0 for 3R4F, THP1.0, NVP and DMSO control respectively. After 5-day CS or aerosol exposure, mean ΔE values were 26.2 ± 3.2, 3.6 ± 1.9, 3.4 ± 1.3, 5.3 ± 0.8 for 3R4F CS, THP1.0, NVP or PBS control, respectively. Both exposure methods demonstrated that THP1.0 and NVP induced minimal staining, mean ΔL* , Δa* , Δb* and ΔE values were comparable to DMSO or PBS controls.

CLINICAL SIGNIFICANCE

For the first time, diverse NGPs across the risk continuum were assessed in vitro for their impact on enamel staining. CS exposure significantly increased the level of bovine enamel sample discoloration, whereas THP1.0 or NVP exposure resulted in values comparable to the controls.

Randomized exploratory study to measure ion release from calcium sodium phosphosilicate-containing dentifrice

This exploratory study investigated salivary concentrations of silicon, calcium, sodium, and phosphorous over a 60-min time period following the use of a calcium sodium phosphosilicate (CSPS)-containing dentifrice. Participants brushed with a dentifrice containing 5% (w/w) or 0% (w/w) CSPS or swilled with a slurry containing 5% (w/w) CSPS/glycerol. Saliva samples were collected before, and 2, 5, 15, and 60 min after, product use and were analysed using inductively coupled plasma optical emission spectroscopy. Intra-oral pH measurements were also taken. Primary analysis was of centrifuged saliva supernatant containing only dissolved material. At most time points, the CSPS-containing dentifrice and slurry generated significantly more salivary silicon than the dentifrice containing 0% CSPS. At 2-15 min after brushing there was significantly more salivary calcium after use of the CSPS-containing dentifrice and slurry, compared with the 0% CSPS dentifrice; a significant reduction, from baseline, in salivary calcium after use of dentifrice containing 0% CSPS; and an increase in salivary sodium after use of dentifrices containing either 5% or 0% CSPS, but no differences between them. Salivary phosphorous concentration decreased significantly with all treatments 2-5 min after use. There were no significant between-treatment differences in intra-oral pH. Products were generally well tolerated. This study establishes that it is possible to measure changes in salivary ionic composition derived through oral retention of CSPS, delivered via a dentifrice.

Improved Performance of Ionic Liquid Supercapacitors by using Tetracyanoborate Anions

Supercapacitors are energy storage devices designed to operate at higher power densities than conventional batteries, but their energy density is still too low for many applications. Efforts are made to design new electrolytes with wider electrochemical windows than aqueous or conventional organic electrolytes in order to increase energy density. Ionic liquids (ILs) with wide electrochemical stability windows are excellent candidates to be employed as supercapacitor electrolytes. ILs containing tetracyanoborate anions [B(CN)₄] offer wider electrochemical stability than conventional electrolytes and maintain a high ionic conductivity (6.9 mS cm⁻¹). Herein, we report the use of ILs containing the [B(CN)₄] anion for such an application. They presented a high maximum operating voltage of 3.7 V, and two‐electrode devices demonstrate high specific capacitances even when operating at relatively high rates (ca. 20 F g⁻¹ @ 15 A g⁻¹). This supercapacitor stored more energy and operated at a higher power at all rates studied when compared with cells using a commonly studied ILs.

Ionic liquids containing tricyanomethanide anions: physicochemical characterisation and performance as electrochemical double-layer capacitor electrolytes

Fluorine free ionic liquids with low density and high ionic conductivity for high energy electrochemical double-layer capacitors.

Influence of Particle Size Distribution on the Performance of Ionic Liquid-based Electrochemical Double Layer Capacitors

Electrochemical double layer capacitors (EDLCs) employing ionic liquid electrolytes are the subject of much research as they promise increased operating potentials, and hence energy densities, when compared with currently available devices. Herein we report on the influence of the particle size distribution of activated carbon material on the performance of ionic liquid based EDLCs. Mesoporous activated carbon was ball-milled for increasing durations and the resultant powders characterized physically (using laser diffraction, nitrogen sorption and SEM) and investigated electrochemically in the form of composite EDLC electrodes. A bi-modal particle size distribution was found for all materials demonstrating an increasing fraction of smaller particles with increased milling duration. In general, cell capacitance decreased with increased milling duration over a wide range of rates using CV and galvanostatic cycling. Reduced coulombic efficiency is observed at low rates (<25 mVs⁻¹) and the efficiency decreases as the volume fraction of the smaller particles increases. Efficiency loss was attributed to side reactions, particularly electrolyte decomposition, arising from interactions with the smaller particles. The effect of reduced efficiency is confirmed by cycling for over 15,000 cycles, which has the important implication that diminished performance and reduced cycle life is caused by the presence of submicron-sized particles.

Ionic liquid based EDLCs: influence of carbon porosity on electrochemical performance

Electrochemical double layer capacitors (EDLCs) are a category of supercapacitors; devices that store charge at the interface between electrodes and an electrolyte. Currently available commercial devices have a limited operating potential that restricts their energy and power densities. Ionic liquids (ILs) are a promising alternative electrolyte as they generally exhibit greater electrochemical stabilities and lower volatility. This work investigates the electrochemical performance of EDLCs using ILs that combine the bis(trifluoromethanesulfonyl)imide anion with sulfonium and ammonium based cations. Different activated carbon materials were employed to also investigate the influence of varying pore size on electrochemical performance. Electrochemical impedance spectroscopy (EIS) and constant current cycling at different rates were used to assess resistance and specific capacitance. In general, greater specific capacitances and lower resistances were found with the sulfonium based ILs studied, and this was attributed to their smaller cation volume. Comparing electrochemical stabilities indicated that significantly higher operating potentials are possible with the ammonium based ILs. The marginally smaller sulfonium cation performed better with the carbon exhibiting the largest pore width, whereas peak performance of the larger sulfonium cation was associated with a narrower pore size. Considerable differences between the performance of the ammonium based ILs were observed and attributed to differences not only in cation size but also due to the inclusion of a methoxyethyl group. The improved performance of the ether bond containing IL was ascribed to electron donation from the oxygen atom influencing the charge density of the cation and facilitating cation–cation interactions.

Ether-Bond-Containing Ionic Liquids as Supercapacitor Electrolytes

Electrochemical capacitors (ECs) are electrical energy storage devices that have the potential to be very useful in a wide range of applications, especially where there is a large disparity between peak and average power demands. The use of ionic liquids (ILs) as electrolytes in ECs can increase the energy density of devices; however, the viscosity and conductivity of ILs adversely influence the power density of the device. We present experimental results where several ILs containing different cations have been employed as the electrolyte in cells containing mesoporous carbon electrodes. Specifically, the behavior of ILs containing an ether bond in an alkyl side chain are compared with those of a similar structure and size but containing purely alkyl side chains. Using electrochemical impedance spectroscopy and constant current cycling, we show that the presence of the ether bond can dramatically increase the specific capacitance and reduce device resistance. These results have the important implication that such ILs can be used to tailor the physical properties and electrochemical performance of IL-based electrolytes.

Melamine-formaldehyde-NTA chelating gel resin: Synthesis, characterization and application for copper(II) ion removal from synthetic wastewater

A new chelating resin was synthesised by anchoring nitrilotriacetic acid (NTA) to melamine during the melamine-formaldehyde gelling reaction in the presence of water, using acetone and guaiacol as a porogen mixture. This technique gives a porous chelating gel resin capable of removing heavy metals from wastewater. FT-IR, XRD, elemental analysis, surface area and water regain measurements were conducted for characterization of the new chelating gel resin. A comprehensive adsorption study (kinetics isotherm, and thermodynamics) of Cu(II) removal from synthetic acidic aqueous solutions by adsorption on this resin was conducted regarding the effects of time, temperature, initial pH and copper(II) initial concentration.

Plaque antibacterial levels following controlled food intake and use of a toothpaste containing 2% zinc citrate and 0.3% Triclosan

OBJECTIVES

To measure the levels of zinc and Triclosan present in plaque 12 hours post-brushing and following two weeks home use of a toothpaste formulation containing 2% zinc citrate and 0.3% Triclosan. To measure the levels of zinc and Triclosan in plaque following two weeks home use of the test toothpaste formulation together with a further morning's brushing and a day of controlled food intake.

METHODS

A total of 104 subjects completed the study. Plaque samples were taken before use of the test toothpaste and again after a specified regime of product use and food intake. The samples were analysed for zinc or Triclosan.

RESULTS

Levels of zinc and Triclosan in plaque 12 hours after last brushing and following a 2-week home usage of product, were 149.1 microg/g and 8.6 microg/g respectively. Following a morning brushing and a day of controlled food intake zinc and Triclosan levels were 94.7 microg/g and 4.1 microg/g respectively. These levels of agents were found to reduce pH drop in vitro.

CONCLUSIONS

Regular use of a toothpaste containing 2% zinc citrate and 0.3% Triclosan can lead to a build-up of antibacterial agents in plaque that continue to work even after controlled food intake.

Planning an integrated population-based program

Social, economic, and political pressures demand that hospitals focus on ways to provide cost-effective, population-based care. As a member of the hospital executive staff, nurse administrators need to have a method for analyzing, planning, implementing, and evaluating prospective programs and be able to articulate their potential and relative worth in terms of cost, quality, and value. The author presents a template model for integrated population-based program planning. Children's Home-Based Asthma Management and Prevention Service (CHAMPS) is presented to illustrate application of the model.

Increased frequency of DR4 in systemic onset juvenile chronic arthritis

Eighty-one patients with systemic onset juvenile chronic arthritis (JCA) have been tested for HLA-A, -B, -C, and -DR antigens. This study confirms previous reports of an increased incidence of DR4 in these patients. Subdivision of the patients according to their disease course over ten years showed different HLA associations with different disease courses. The frequency of DR4 tended to be greater in patients with less severe disease. There was also an increased incidence of HLA B27 in patients in whom relapses of disease were associated with intercurrent infections.

Treated xenografts as gliding tendon prostheses in an ovine model

A model for testing the properties of gliding tendon grafts has been developed that allows anastomoses to be evaluated separately from the mid-portion of the graft. In addition, two different graft materials may be implanted in one sheep foreleg whilst maintaining control (not operated) tendons in both the operated leg and contralateral foreleg. The model has been used to evaluate the response of xenografts made from chemically treated kangaroo tail tendon (KTT) compared with autografts. At 3 month the mid-sections of the glutaraldehyde-fixed xenografts maintained between 57 and 82% of their initial ultimate tensile strength whereas lyophilized KTT dropped to 10% and autografts retained 91% of initial strength. Sterilization by gamma-radiation of wet xenografts did not affect the material and implant properties significantly. Longer term studies are necessary to determine the resorption behaviour of the xenografts. Anastomosis strengths were found to be about the same for all grafts, at about 25% of the strength of the original tendon. Alternatives need to be investigated to improve this strength.

Autograft and Leeds-Keio reconstructions of the ovine anterior cruciate ligament

This study compared the Leeds-Keio prosthesis with grafting of autogeneic patellar tendon for the reconstruction of the ovine anterior cruciate ligament under controlled conditions. Reconstructed knees from six sheep of each group were evaluated at 12, 26, and 52 weeks postreconstruction with respect to clinical assessment, gross pathology, mechanical properties, and histology. Although no difference in clinical assessment (anteroposterior draw, range of motion, and function) was noted between the prosthesis reconstruction and the autograft reconstruction, the prosthesis provided a higher strength initially, which remained relatively constant over the one-year study. However, prosthesis wear was observed, with up to 50% of Dacron fibers ruptured in some cases. Histologic sections indicated that in the ovine model, the Leeds-Keio prosthesis should be considered an artificial device and not a scaffold or stent that supports aligned collagenous growth. The autograft had low strength at 12 weeks, which increased over the study period. Despite acceptable clinical performance and adequate mechanical properties up to one year postimplantation, neither reconstruction approached the clinical or mechanical performance of the normal anterior cruciate ligament in the ovine model.

HLA and complement C4 antigens in polyarticular onset seronegative juvenile chronic arthritis: association of early onset with HLA-DRw8

HLA-A,B,C,DR and DQ antigens were tested in 53 British Caucasian patients with polyarticular onset seronegative juvenile chronic arthritis (JCA); C4 allotypes were also tested in 46. A strong association with HLA-DRw8 was found (RR = 6.1, Fp = 7.6 x 10(-5)), with increased -B5(51) and C4A QO, and decreased -DR7 frequencies. DRw8 incidence correlated with an onset under 5 years, 9 of 12 DRw8+ cases being in this subgroup (Fp = less than 0.06), whereas B5 and C4A QO were prevalent in late onset (greater than or equal to 5 years). Erosions after 5 years associated with HLA-DRw6, and their absence with -Cw1 and -DR5. Genetic susceptibility factors and a further subdivision by onset age are thus demonstrated in this disease. Comparative data suggest that the genetic basis of susceptibility to early onset disease is similar to that of pauciarticular JCA.

Bovine serum sialic acid: age-related changes in type and content

1. The sialic acid content of newborn calf serum (4.8 mumol/ml) is approx. 3-fold higher than that of mature animals (1.4 mumol/ml) and decreases to 2.4 mumol/ml at 20 days of age. Colostrum-fed and colostrum-deprived calves have similar levels of sialic acid from birth to 14 days of age. 2. The high level of sialic acid in newborn calf serum is due predominantly to N-acetylneuraminic acid, since this sialic acid accounts for 93% of the total and since less than 5% of the sialic acid is O-acetylated. 3. Comparison of day 0 and day 20 serum by gel filtration and by SDS polyacrylamide gel electrophoresis demonstrates that the increase in sialic acid is associated with increased production and/or sialylation of components with MW of 45-60 kDa. 4. A high percentage (64%) of the sialic acid in newborn calf serum is detected with the lipid-linked sialic acid assay, relative to 20 day old (25%) or mature (18%) animals. 5. This indicates that the glycoproteins of newborn calf serum are more efficiently extracted under the conditions of this assay than glycoproteins of mature serum.

Nausea and vomiting after prostaglandins in day case termination of pregnancy. The efficacy of low dose droperidol

The antiemetic effects of low dose droperidol (0.25 and 0.5 mg) and a placebo were compared in patients who had received prostaglandin for day case termination of pregnancy. The incidence of nausea and vomiting was high. Low dose droperidol significantly reduced postoperative nausea and vomiting without any delay in immediate recovery or discharge home (p less than 0.05). Droperidol 0.25 mg was equally effective as an antiemetic, as 0.5 mg.

HLA antigen frequencies among patients with juvenile chronic arthritis and amyloidosis: a brief report

Amyloidosis is seen in a small number of patients with juvenile chronic arthritis (JCA). In order to determine whether particular HLA markers might predispose to the development of amyloid in JCA a group of 45 patients with amyloidosis confirmed by biopsy was typed for the HLA-A, B, C and DR loci. The results confirmed previous smaller studies that no HLA antigen detected by standard serological techniques was associated specifically with the development of amyloidosis. Those antigens which showed an altered frequency (ie. DR4 and DRw8) were known to be associated with the different types of JCA onset represented in this group.

Genetic susceptibility to early onset pauciarticular juvenile chronic arthritis: a study of HLA and complement markers in 158 British patients

To investigate the genetics of susceptibility to early onset pauciarticular juvenile chronic arthritis (JCA), 158 unrelated ethnic British patients with a mean disease onset of 3.2 years, together with controls, were tested for HLA-A, B, C, and DR antigens. Additionally, 117 patients were also investigated for complement Bf and C4 markers. New observations included an increased frequency of the C4B 2 allotype (p corrected (pc) less than 0.02) and C4A 4,B 2 phenotype (p less than 0.0005). Findings suggested a unique increase of the haplotype HLA-DRw8, Bf*S, C4A*4, C4B*2, HLA-B39, possibly predisposing to more severe disease. Strong positive associations were confirmed with HLA antigens A2 (pc = 2.5 X 10(-8)), DRw8 (pc = 3.5 X 10(-14)), DR5 (pc less than 0.02), DRw52 (pc = 2.8 X 10(-6)) and DR5, w8 phenotype (pc = 3.9 X 10(-6)), and negative associations with DR7 (pc = 5.8 X 10(-7)), DR4 (pc less than 0.002), and DRw53 (pc = 0.004). Antinuclear antibody (ANA) seropositivity correlated with DR5 (p less than 0.02), and in children with chronic iridocyclitis (CIR) Bw62 incidence was raised (p less than 0.03) and B44 reduced (p less than 0.03). HLA-A2 was found in 88% of ANA+, CIR+ patients (p less than 0.01). A significant excess of DR5, w8 heterozygotes was present (relative risk = 41.1) and a lack of corresponding homozygotes. Results are inconsistent with a recessive, dominant, or intermediate mode of inheritance of susceptibility, and favour the existence of at least two DR linked 'disease' genes. Moreover, there may be an interaction in heterozygotes of combinatorial factors associated with DR5 and DRw8 in enhancing susceptibility. Possible immunogenetic mechanisms underlying the observed associations with three antigen classes are discussed. Evidence here suggests a role for the HLA-DQ locus in determining susceptibility to this disease.

[3H]Indole-3-acetyl-myo-inositol hydrolysis by extracts of Zea mays L. vegetative tissue

[3H]Indole-3-acetyl-myo-inositol was hydrolyzed by buffered extracts of acetone powders prepared from 4 day shoots of dark grown Zea mays L. seedlings. The hydrolytic activity was proportional to the amount of extract added and was linear for up to 6 hours at 37 degrees C. Boiled or alcohol denatured extracts were inactive. Analysis of reaction mixtures by high performance liquid chromatography demonstrated that not all isomers of indole-3-acetyl-myo-inositol were hydrolyzed at the same rate. Buffered extracts of acetone powders were prepared from coleoptiles and mesocotyls. The rates of hydrolysis observed with coleoptile extracts were greater than those observed with mesocotyl extracts. Active extracts also catalyzed the hydrolysis of esterase substrates such as alpha-naphthyl acetate and the methyl esters of indoleacetic acid and naphthyleneacetic acid. Attempts to purify the indole-3-acetyl-myo-inositol hydrolyzing activity by chromatographic procedures resulted in only slight purification with large losses of activity. Chromatography over hydroxylapatite allowed separation of two enzymically active fractions, one of which catalyzed the hydrolysis of both indole-3-acetyl-myo-inositol and esterase substrates. With the other enzymic hydrolysis of esterase substrates was readily demonstrated, but no hydrolysis of indole-3-acetyl-myo-inositol was ever detected.

Metabolism of tryptophol in higher and lower plants

Bacteria, thallophytes, and seed plants (107 species), supplied with exogenous indole-3-ethanol (tryptophol), formed one or more of the following metabolites: O-acetyl tryptophol, an unknown tryptophol ester (or a set of structurally closely related esters), tryptophol glucoside, tryptophol galactoside, indole-3-acetic acid (IAA), and indole-3-carboxylic acid. The unknown ester was formed by all species examined; O-acetyl tryptophol appeared sporadically in representatives of most major taxonomic groups. Tryptophol galactoside was found in the algae Chlorella, Euglena, and Ochromonas. The glucoside was formed by many eucaryotic plants, but not by bacteria; it was a significant tryptophol metabolite in vascular plants. IAA, if detectable at all, was usually a minor metabolite, as should be expected, if tryptophol oxidase responds to feedback inhibition by IAA. Indole-3-carboxylic acid, formed by a few fungi and mosses, was the only tryptophol metabolite detected which is likely to be formed via IAA.

Immunoglobulin allotypes in families with pauciarticular-onset juvenile chronic arthritis

Immunoglobulin allotypes have been studied in the families of 17 pauciarticular-onset juvenile chronic arthritis patients included in the 9th Histocompatibility Workshop. There is no evidence of an association of these genetic factors with the disease, nor with the HLA and complement C4 disease markers.

Educating patients with rheumatoid arthritis: a prospective analysis

Twenty-two men with rheumatoid arthritis were randomly assigned to either a patient education group, receiving standard inpatient medical care in addition to a formal education program, or a control group receiving only the inpatient medical care. Members of the groups were not significantly different in terms of age, degree of life stress, socioeconomic status, educational level, or years since onset of rheumatoid arthritis. Dependent measures included the Arthritis Knowledge Inventory (AKI), the Arthritis Impact Measurement Scales (AIMS), and the Beck Depression Inventory (BDI), and they were collected preeducation, posteducation, and at a three-month followup. Results from the AIMS revealed improvement in dexterity, social role, depression, and overall health status for both groups. The BDI also revealed significantly less depression for both groups, reflecting a general improvement following medical intervention. Although the patient education group revealed significantly higher scores on the knowledge measure, they also revealed significantly more impairment of activity levels and significantly higher pain scores. Education was effective for increasing rheumatoid arthritis knowledge, but such topics as joint protection and disease process may adversely affect how patients view their physical capacities and interpret their pain.

HLA antigens in coeliac disease associated with malignancy

Coeliac patients are at greater risk than the general population of developing malignant neoplasms, particularly lymphomas. The establishment at the Clinical Research Centre of a national collaborative study of coeliac patients with malignancy provided the opportunity to carry out HLA typing for 55 HLA-A, B and C and the 10 recognised DR antigens on a group of coeliac patients with malignancy. Study of a sample of 44 patients with biopsy proven coeliac disease and histologically confirmed malignancy, including 12 with malignant histiocytosis, and 57 coeliac patients without malignancy, failed to show any significant differences in antigen frequencies between patients with and without malignancy. These results indicate that there are no HLA genetic markers associated specifically with the development of malignancy in coeliac disease.

HLA antigens in East African Black patients with Burkitt's lymphoma or nasopharyngeal carcinoma and in controls: a pilot study

A pilot study is reported of HLA-A, B, and C antigens in 141 East African Blacks comprising patients with Burkitt's lymphoma or nasopharyngeal carcinoma, either with active disease or in long-term remission, together with comparable controls. This study forms part of a wider program investigating host factors in these diseases. A protocol was selected for optimal testing of cells processed and cryopreserved between 1972 and 1976, largely under field conditions, which employed a two-color fluorochromasia typing procedure. Antigen distribution and computed haplotype frequencies in the total unrelated population are given. New findings include an approximately equal frequency of Aw23 and Aw24, a high (18%) incidence of Bw21, and the gametic associations of Aw36 with Bw44, and Aw30 with Bw45. Of the major group of B15-related antigens reported earlier. SV is the most common, and there are strong linkages of SV with Cw2 and Bu with Cw3. The possible presence of further variants at the A- and B-loci is reported. The proportion of B-locus antigen "blanks" in this study is 5.9%. Relationships have been sought between the HLA antigens and diseases studied: the antigen A29, possibly in linkage with Bw42, shows a correlation with disease susceptibility, and associations are suggested between Bw44 (in possible combination with Aw36) and resistance to both BL and NPC, and between Bw45 and long-term remission in NPC.

Distribution of Free and Ester Indole-3-Acetic Acid in the Cortex and Stele of the Zea mays Mesocotyl

The distribution of free and ester-linked indole-3-acetic acid (IAA) in the vascular stele and cortex-epidermis of the Zea mays mesocotyl was measured by gas chromatography-selected ion monitoring-mass spectrometry and by radioimmunoassay with good agreement between the two assay methods. On a per plant basis, 72% of the free IAA was found in the stele and 28% was in the cortex, whereas 80% of the ester IAA was in the cortex with 20% localized in the stele. On a fresh weight basis, the concentration of free IAA was 15 to 28 times higher in the stele than in the cortex, whereas the concentration of ester IAA was similar in the two tissues. The concentration of free IAA in the apical portion of the cortex was 3 times higher than in the basal portion, and this distribution correlated with the relative growth rates of the apical and basal portions of the mesocotyl. No changes in the longitudinal distribution of ester IAA were found in either the cortex or stele.

B15 heterogeneity in East African Blacks

One-hundred-forty-one Blacks (135 unrelated) from Kenya and Tanzania have been tissue-typed (HLA-A, B and C loci) as part of a study of host factors involved in Burkitt's lymphoma and naso-pharyngeal carcinoma. Evidence is presented for the existence in this population of several B15-related antigens which together occur with a relatively high frequency of 30% in unrelated individuals. It is likely that these variants may include the antigens SV and perhaps Bu recently defined with population frequencies of under 1% in Caucasians. In the absence of monospecific typing sera, identification of these variants may be helped by their apparently strong association with C-locus antigens in Blacks. Recognition of these B15 variants has been largely responsible for reducing the proportion of unidentified or "blank" B-locus antigens in this population to only 6%. These findings substantiate and amplify previous reports suspecting the presence of such antigens in Blacks, and should facilitate studies of possible associations of disease with HLA in these populations.

Lone aortic regurgitation, sacroiliitis, and HLA B27. Case history and frequency of association

An account of aortic regurgitation complicating ankylosing spondylitis is given. Twenty patients with lone aortic regurgitation and without overt spondylitis were examined clinically and radiologically and tissue typed. No evidence of sacroiliitis could be found in any patient. HLA B27 was absent from this group, and no significant disturbance in antigen frequency was noted.

An in vitro study of the effects of calcium on the cardiovascular actions of thiopentone, althesin and ketamine in the rat

The actions of three intravenous anaesthetics, Althesin, thiopentone and ketamine have been compared on the rat isolated atria and portal vein. Although the three anaesthetics had grossly similar actions on the two preparations. i.e. depression of atrial rate and depression of the amplitude of myogenic activity in the portal vein, there were enough differences to suggest that they produced their effects by different mechanisms. These differences were particularly obvious in interactions with noradrenaline and the effects of changes in calcium ion concentration on the concentration effect relationships for the agents on the atria and portal vein. Generally Althesin was unaffected by changes, but in qualitatively different ways.

Pesticin-dependent generation of somotically stable spheroplast-like structures

Homogenous pesticin, a bacteriocin produced by Yersinia pestis, promoted rapid dose-dependent killing of Escherichia coli phi but permitted residual generation of cell mass. Both growing cells and those blocked in net synthesis of nucleic acids or protein were converted by pesticin to osmotically stable spheroplast-like forms. Morphology and viability of cells starved for fermentable carbohydrate were not affected by pesticin. Similar spheroplast-like structures were formed from sensitive cells of Yersinia pseudotuberculosis, Yersinia enterocolitica, and Y. pestis.

The mechanism of T cell mediated cytotoxicity. IV. Studies on communicating junctions between cells in contact

A modified autoradiographic technique has been developed which makes it possible to demonstrate the intercellular transfer of diffusible molecules through communicating junctions. This technique has been used to decide whether or not there is a cytoplasmic union between cytotoxic lymphocytes and the target cells they destroy. The transfer of 51 Cr, [ 3 H]uridine and [ 3 H]choline has been demonstrated between human diploid cell line cells (MRC 5) in contact. This has provided a system in which the techniques could be assessed. The demonstration that 51 Cr can pass through communicating junctions provides a unique system for the investigations of these structures. Despite the fact that all three labels could transfer between MRC 5 cells in contact, no transfer between cytotoxic T cells and P815 target cells could be demonstrated during a cytotoxic reaction. The reported transfer of fluorescein can probably be attributed to the transfer of fluorescein ester via the extracellular space. It is concluded, therefore, that communicating junctions of the type that can form between certain mammalian cells in contact do not contribute to the mechanism of T cell cytotoxicity.

Precipitating antibody response to malarial S-antigens

The gel diffusion test has been used to detect antibodies to malarial S-antigens. Sera were obtained from entire Gambian village communities, from young children with acute P. falciparum malaria, from children convalescent from such infections and from immune adults. In community studies, small selections of S-antigens detected antibody frequently in sera from older persons but rarely in sera from young children. Larger panels of antigens detected antibodies in sera from half of 50 malarious children while homologous antibody responses were observed in 22% of 267 children followed at intervals during convalescence from malaria. In these latter cases, antibody tended to appear more swiftly when antigen was lost rapidly from the circulation, and observations made on individual responses indicated that antibody production was influenced by factors other than the intrinsic properties of the antigens. In adult sera antibodies usually occurred in association with IgG.

Persistence and recurrence of S-antigen in Plasmodium falciparum infections in man

The persistence of heat stable malarial antigens (S-antigens) in the sera of Gambian children following treatment for severe Plasmodium falciparum infections was investigated. In most cases S-antigens ceased to be demonstrable within 7 days but in some they were detected for several weeks and their persistence correlated with both the density of parasitaemia and the antigen titre observed before treatment. An exponential loss of circulating antigen was, in the majority of individuals, accelerated by some other factor which might have been homologous antibody. Renewal of asexual parasitaemia usually resulted in reduction in the rate of antigen loss or in an increase in antigen level. When the aparasitaemic interval was a month or less the antigens associated with different parasitaemic episodes usually showed identical specificities; when the interval was longer they were usually antigenically distinct. These findings may indicate that relapse parasites usually show the same S-antigen specificities as their progenitors while parasites arising from distinct infections tend to show different specificities and could therefore support a view that considerable antigenic heterogeneity exists among the parasites that comprise P. falciparum populations in endemic areas.

Effect of Ca2+ on morphology and division of Yersinia pestis

Wild-type cells of Yersinia pestis are known to exhibit a nutritional requirement for physiological levels of Ca(2+) ( approximately 2.5 mM) at 37 but not 26 C. Upon shift of Ca(2+)-deficient cultures from 26 (permissive condition) to 37 C (restrictive condition), bacterial mass quadrupled as the organisms doubled in number and then became elongated to about twice their normal size. As shown in thin sections, the resulting static cells contained axial filaments which differed from the typical irregularly lobate nucleoids of normal yersiniae grown under the permissive condition. Following prolonged cultivation under the restrictive condition (12 h), the organisms generally exhibited apparent degenerative changes, including separation or infolding of the cell wall and cytoplasmic membrane, degeneration of deoxyribonucleic acid, and appearance of vacuoles within the cytoplasm. At this time, the cells were unable to reinitiate cell division at 37 C upon addition of Ca(2+) but divided in partial synchrony after return to 26 C. This observation indicated that, at 37 C, continuous exposure to Ca(2+) is necessary for yersiniae to maintain normal morphology and the ability to divide.