Slot optical waveguide usage in forming passive optical devices

We have reviewed the work on SOI slot optical waveguides followed by our work. In a slot waveguide structure, light can be confined in a low index slot guarded by high index slabs. Slot structures are being used in forming complex structures; such as ring resonator circuits. The increased round trip in ring resonator circuits signifies the importance of dispersion calculations. We did analytical and numerical investigations of slot structures' dispersion characteristics. Our dispersion tuned slot structures can help in reducing the dispersion effects on optical signal, which will in turn improve the efficiency of light-on-chip circuits. Since the advent of slot optical waveguides, SOI based slot optical waveguides have been under consideration. It has been found that glass based slot optical waveguide structures with relatively low refractive index contrast ratio can also play an important role in forming complex nano-size optical devices. We made use of power confined inside low index slot regions for a double slot structure. Opto-mechanical sensors have been proposed based upon: (a) variation in power confined inside low index slot region due to the movement of central high index slab under the action of external force (temperature, pressure, humidity, etc). vide Chinese Patent No. ZL 200710176770.1, 2007 (b) variation in power confined inside low refractive index slot regions due to movement of both slots under the action of external force (temperature, pressure, humidity, etc).

P3-07-38: Selective Omission of Blue Dye in Patients Undergoing Sentinel Lymph Node Biopsy for Breast Cancer

Background

Combined blue dye and radioisotope colloid injection with scintigraphy is standard practice for mapping and biopsy of sentinel lymph node in breast cancer within the UK. Whilst this combination aids sentinel node detection rate, blue dye has a number of possible adverse effects including anaphylaxis (reported as 1–3% of patients), semi-permanent skin tattooing and staining of bodily fluids which may cause distress for the unwary patient. It can also cause obscuration of the operating field, making identification and dissection of planes more difficult.

Methods: Patients undergoing sentinel lymph node biopsy (SLNB) using either a combination of blue dye and radioactive colloid, or radioactive colloid alone during a 14 month period were compared for identification rate, node harvest number and final positive rate. A total of 122 axillary sentinel node biopsies in 121 patients were identified. All patients scheduled for sentinel lymph node biopsy had intradermal injection of radiocolloid and lymphoscintigram preoperatively and were checked for radioactive intensity with gamma probe on the table before draping for surgery. Patients with good signal proceeded to surgery without blue dye. Those with more than 3 nodes (n=9), radioisotope skin contamination (n=2), absent signal on scintigraphy (n=7) and/or with weak pre-operative radioactive signal (n=22) were given 2 millilitres of patent V dye subdermally in the periareolar region. Sentinel node biopsy then proceeded in the standard fashion. Data was also collected from the year prior to be used as a control group, where the combination of blue dye and radioisotope was used for all patients (n=90), and compared with the group receiving radioisotope alone.

Results: The rate of identification for single agent and dual agent was 100% and 97.5% respectively, with no significant difference in mean node harvest using radioisotope alone (1.80) as compared to combined technique (1.87 p= 0.88, 95%CI −0.39 to 0.34). There was no significant difference in the number of patients with positive nodes on final histology when using single agent (13 (14%)) when compared to the dual agent technique (10 (25%) p=0.21). There was also no difference in the rate or number of node harvest in the group who underwent the single agent technique when compared to the control group (100% identification, mean harvest 1.84, p=0.77, 95% CI −0.36 to 0.27), with no difference in node positivity (16 (17%) p=0.68). No intra operative adverse reaction was reported in any of the groups.

Discussion: This study has shown no significant difference in the localisation rate when selectively omitting blue dye in suitable patients compared to the combined technique. This may be due to significant operator experience or change in the method of radioisotope injection since initial studies were performed. In this study, 86 out of 126 SLNB proceeded without blue dye, meaning not only a reduction in the number of patients with minor adverse effects, but also a potential reduction in severe adverse reaction of 68% or 2 patients per year within this breast unit.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-07-38.

P3-07-31: Intra-Operative Assessment of Sentinel Lymph Nodes in Breast Cancer with Touch Imprint Cytology (TIC) in 460 Consecutive Patients

Background

Sentinel node biopsy (SNB) accurately predicts the axillary lymph node status in patients with breast cancer. The sentinel lymph node (SLN) is evaluated by routine histology, requiring 3–5 days for the results and a second operation if the SLN is positive. However a second operation can be avoided if a reliable intraoperative assessment of the SLN was available. The techniques used for intra-operative assessment of the SLN include frozen section, touch imprint cytology (TIC) and more recently molecular biology assays. The aim of this study was to evaluate the accuracy of TIC in the assessment of the SLN.

Methods: A prospective study to include 460 patients with breast cancer who underwent SNB and had the sentinel node assessed intra-operatively with TIC. The SLN was bisected and a touch imprint was made on to a slide. The imprint was stained with Giemsa stain. Permanent sections were evaluated with H&E and immunohistochemical staining. The TIC results were compared with the final histology of the SLN.

Results: 766 SLN's were harvested from 460 patients (Mean - 1.66). Of the 460 patients, TIC was falsely negative in 50(24%) patients. No patients had false positive results. Negative predictive value was 87%. The accuracy rate was 89%. 94 patients were positive on histology. TIC was positive in 44 patients and negative in 50. The sensitivity, specificity and positive predictive value of TIC was 47%, 100% and 100% respectively. By acting on the results of TIC, 44 patients (47%) had an axillary clearance at the primary operation and were thus spared a second operation.

Conclusion: TIC in our cohort of 460 patients and 766 sentinel lymph nodes had an accuracy rate of 89% and specificity of 100%. Our study compares favourably with published literature, confirming that TIC is a simple, quick, reliable and reproducible technique that can be used for intra operative assessment of the SLN. A sensitivity of 47% means that about half of the SLN positive patients were spared a second operation. We had hoped that with more experience, our sensitivity would improve but since this has not been the case we are now moving towards molecular biology assays (OSNA) to assess the SN intra-operatively.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-07-31.

Successful pregnancy after liver transplantation in progressive familial intrahepatic cholestasis, type 1

A woman who had undergone liver transplantation for genetically documented ATP8B1 disease/progressive familial intrahepatic cholestasis, type 1, successfully conceived, carried, and was delivered of a healthy child. The pregnancy and its management are described; implications are discussed.

Monoparesis secondary to herpes zoster

We describe a 90-year-old woman with right upper limb monoparesis secondary to varicella zoster virus infection as a result of extensive inflammatory involvement of the entire brachial plexus at root level. To our knowledge, this is the first report of entire brachial plexus involvement in a living patient of such advanced age. Despite a delay in presentation and thus initiation of treatment, a favourable clinical response was observed.

Role of mammography in the triple assessment of single-quadrant breast symptoms

Background

Most women over the age of 35 years referred to a breast clinic have single-quadrant symptoms and undergo mammography (MMG) as part of the triple assessment of these. A proportion of these women has no abnormality clinically or on ultrasonography (P1 U1). The aim of this study was to assess the additional contribution of MMG in diagnosing cancer in patients with P1 U1 findings and to consider whether it is safe to be more selective when requesting MMG.

Methods

Over a 2-year interval the clinical and radiological details of women whose single-quadrant breast symptoms were assessed as P1 U1, and who were then sent for MMG, were entered into a database. The results of further investigations initiated by a non-benign MMG report were recorded, and the patients reviewed to establish how many cancers were diagnosed purely by MMG and whether these were located at the site of symptoms.

Results

There were 454 women in the study group, representing 17·5 per cent of all new referrals. Twenty-one patients (4·6 per cent) were recalled following a non-benign MMG result, ten of whom required image-guided biopsy. Cancer was diagnosed in three patients (0·7 per cent of the study group), located in the contralateral breast in two women and a different ipsilateral quadrant in one.

Conclusion

MMG in this subset of patients did not increase the cancer detection rate at the site of symptoms and therefore constituted screening. The rationale for requesting MMG in these patients, and indeed for applying the triple assessment rule, should be reconsidered.

Development of flexible LEO-resistant PI films for space applications using a self-healing mechanism by surface-directed phase separation of block copolymers

Polimide-block-polydimethylsiloxane (PI-b-PDMS) block copolymers have been synthesized from commercially available amino-terminated polysiloxanes with different molecular weights, for use as polymeric materials resistant to the low earth orbit (LEO) space environment. A structural optimization with respect to maximum environmental protection has been performed by varying the PDMS block length as well as the architecture of the block copolymers spanning from multiblock to triblock and star-shaped morphologies. The synthesized polymers and casted films show good mechanical and thermal performance. For block copolymers with a load of 2% PDMS (in the case of the multiblock copolymers), a complete surface coverage of the PDMS has been found. It has been shown that the transfer of the surface enriched PDMS layer into a thin silica layer after atomic oxygen (AO) exposure results in a drastic decrease in AO erosion rate. The silica layer protects the underlying material from oxygen initiated erosion resulting in a drastic decrease of surface roughness. This phenomena is observable for loads as small as 6 wt % PDMS.

Use of Strychnos nux-vomica (Azraqi) seeds in Unani system of medicine: role of detoxification

Some plants used in Unani system of medicine are toxic, even deadly poisonous. The drugs having such plants as their components are detoxified before they are dispensed to the patients. One such drug, capsule Hudar, has Strychnos nux-vomica L. (Azraqi) seeds as one of its components and is very effectively used to elevate blood pressure. Ancient manuscripts describe many methods of its detoxification. It has been found that the detoxification processes studied reduce the strychnine content, as determined either by using uv-vis spectrophotometer or HPLC, present in Strychnos nux vomica seeds which is responsible for Strychnos nux vomica toxicity. The decrease in strychnine amount was best when the seeds were immersed for detoxification in excess of water for 5 days, in milk for 2 days followed by their boiling in milk. Strychnine in small amounts has been reported to give subjective feeling of stimulation.

Screening actinomycetes for extracellular peroxidase activity

A diverse collection of actinomycete strains were screened for production of extracellular peroxidase activity by adapting a chemiluminescence analysis system developed for horseradish peroxidase-based enzyme-linked immunosorbent assay. Extracellular peroxidase activity was found to be common but quantitatively variable, and this rapid and sensitive screening system permitted identification of a small group of high-producing strains. A range of spectrophotometric assays were compared for the measurement of peroxidase activity in concentrated culture supernatants of two selected thermophilic streptomycetes. Of these, the peroxide-dependent oxidation of 2,4-dichlorophenol was identified as the most robust and reproducible assay for quantitative studies.

A Change in a Single Midgut Receptor in the Diamondback Moth (Plutella xylostella) Is Only in Part Responsible for Field Resistance to Bacillus thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai

A population (SERD3) of the diamondback moth (Plutella xylostella L.) with field-evolved resistance to Bacillus thuringiensis subsp. kurstaki HD-1 (Dipel) and B. thuringiensis subsp. aizawai (Florbac) was collected. Laboratory-based selection of two subpopulations of SERD3 with B. thuringiensis subsp. kurstaki (Btk-Sel) or B. thuringiensis subsp. aizawai (Bta-Sel) increased resistance to the selecting agent with little apparent cross-resistance. This result suggested the presence of independent resistance mechanisms. Reversal of resistance to B. thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai was observed in the unselected SERD3 subpopulation. Binding to midgut brush border membrane vesicles was examined for insecticidal crystal proteins specific to B. thuringiensis subsp. kurstaki (Cry1Ac), B. thuringiensis subsp. aizawai (Cry1Ca), or both (Cry1Aa and Cry1Ab). In the unselected SERD3 subpopulation (ca. 50- and 30-fold resistance to B. thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai), specific binding of Cry1Aa, Cry1Ac, and Cry1Ca was similar to that for a susceptible population (ROTH), but binding of Cry1Ab was minimal. The Btk-Sel (ca. 600-and 60-fold resistance to B. thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai) and Bta-Sel (ca. 80-and 300-fold resistance to B. thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai) subpopulations also showed reduced binding to Cry1Ab. Binding of Cry1Ca was not affected in the Bta-Sel subpopulation. The results suggest that reduced binding of Cry1Ab can partly explain resistance to B. thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai. However, the binding of Cry1Aa, Cry1Ac, and Cry1Ca and the lack of cross-resistance between the Btk-Sel and Bta-Sel subpopulations also suggest that additional resistance mechanisms are present.

POEMS syndrome: cryoglobulinemia an unusual association

BACKGROUND

Associations between plasma cell dyscrasia and peripheral neuropathy were well recognized as early as the 1950s. In 1980, Bardwick coined the acronym POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein and skin changes).

AIM

We report a 56-year-old woman who presented with excessive sweating, lethargy, intermittent clawing of fingers and painful limb spasms for 2 years. Clinical examination showed hyperpigmented skin lesions, bilateral pleural effusions and organomegaly. Relevant investigations revealed the presence of sensorimotor polyneuropathy, raised cerebrospinal fluid protein, IgM monoclonal band on serum protein electrophoresis, and reactive bone marrow. The patient was treated with combination therapy which included cyclophosphamide, dexamethasone, and intravenous immunoglobulin with moderate response.

CONCLUSION

Presence of cryoglobulinemia in this case has not been described in the literature.

Investigation of mitochondrial protein expression and oxidation in heart muscle in low and high feed efficient male broilers in a single genetic line

The objective of this study was to assess the expression of mitochondrial proteins and oxidized proteins in heart muscle homogenate obtained from male broilers exhibiting either high or low feed efficiency (G:F) phenotypes. Tissue homogenate was prepared from ventricular tissue obtained from broilers with high (0.80+/-0.01, n=8) and low (0.62+/-0.02, n=8) FE. The levels of specific immunoreactive proteins and oxidized proteins (carbonyls) were determined using Western blot analysis. The expression of 6 electron transport chain proteins [complex II, 70S subunit (CII 70S); iron-sulfur-containing protein (ISP), cytochrome b (Cyt b), cytochrome (Cyt c1) (of complex III); and cytochrome oxidase subunit II (COX II) (of complex IV)] and adenine nucleotide translocator 1 (ANT1) were higher in low feed efficiency heart mitochondria, but 1 protein [NAD subunit 6c (NAD6c) (complex I)] was higher in high feed efficiency birds. Protein carbonyl levels, indicative of oxidized proteins, were higher in heart tissue of low compared with high feed efficiency broilers.

Integrated HPLC-MS and (1)H-NMR spectroscopic studies on acyl migration reaction kinetics of model drug ester glucuronides

Acyl glucuronides (AGs) are common, chemically reactive metabolites of acidic xenobiotics. Concerns about the potential of this class of conjugate to cause toxicity in man require efficient methods for the determination of reactivity, and this is commonly done by measuring transacylation kinetics. High-performance liquid chromatography-mass spectrometry (HPLC-MS) and nuclear magnetic resonance (NMR) spectroscopy were applied to the kinetic analysis of AG isomerization and hydrolysis for the 1-beta-O-AGs of ibufenac, (R)- and (S)-ibuprofen, and an alpha,alpha-dimethylated ibuprofen analogue. Each AG was incubated in either aqueous buffer at pH 7.4 or human plasma at 37 degrees C. Aliquots of these samples, taken throughout the reaction time course, were analysed by HPLC-MS and (1)H-NMR spectroscopy and the results compared. For identification of the AGs incubated in pH 7.4 buffer and for analysis of kinetic rates, (1)H-NMR spectroscopy generally gave the most complete set of data, but for human plasma the use of (1)H-NMR spectroscopy was impractical and HPLC-MS was more suitable. HPLC-MS was more sensitive than (1)H-NMR spectroscopy, but the lack of suitable stable-isotope labelled internal standards, together with differences in response between glucuronides and aglycones, made quantification problematic. Using HPLC-MS a specific 1-beta-O-AG-related ion at m/z 193 (the glucuronate fragment) was noted enabling selective determination of these isomers. In buffer, transacylation reactions predominated, with relatively little hydrolysis to the free aglycone observed. In human plasma incubations the observed rates of reaction were much faster than for buffer, and hydrolysis to the free aglycone was the major route. These results illustrate the strengths and weaknesses of each analytical approach for this class of analyte.

Assessment of buffalo semen with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction assay

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, which measures the reduction of MTT, is commonly used to validate the viability of metabolically active cells. This study was conducted to evaluate and validate the MTT assay to assess the spermatozoal viability of Nili-Ravi buffalo bulls and compare the efficiency of the test with the supravital staining technique (eosin and nigrosin) and the hypoosmotic swelling test. Fresh semen samples from breeding Nili-Ravi buffalo bulls (n = 25) were collected using an artificial vagina. After assessing the quality of the semen for routine variables, the MTT assay was carried out in PBS. Results revealed a correlation (r = 0.979; P < 0.001) between the viability of spermatozoa and the rate of reduction of MTT. The other proportions of same semen samples showed a poor relationship between the eosin and nigrosin test (r = -0.25), the hypoosmotic swelling test (r = -0.12), and motility (r = -0.15). However, the MTT assay was found to be superior compared with other tests because it was able to determine those spermatozoa that were more than 90% viable. In conclusion, the MTT assay is a simple, robust test that can be used to select Nili-Ravi buffalo bulls on the basis of spermatozoa quality.

Incidence and factors related to flare-ups in a graduate endodontic programme

AIM

To investigate the incidence and factors related to endodontic flare-ups in nonsurgical root canal treatment (NSRCT) cases completed by graduate endodontic residents at University of Pennsylvania, USA.

METHODOLOGY

Residents at University of Pennsylvania enter all clinical patient records into an electronic database called PennEndo database. Analysis of records of 6580 patients treated from September 2000 to July 2005 revealed a total of 26 patients with flare-ups (0.39%). Patients were categorized to have undergone flare-up when they attended for an unscheduled visit and active treatment, and when they suffered from severe pain and or swelling after initiation or continuation of NSRCT. SAS software was used to develop a logistic regression model with flare-up as a dependent variable. Independent variables included in the model were: history of previous pain, one vs. two visit NSRCT, periapical diagnosis, tooth type, rotary versus hand instrumentation, and lateral versus vertical compaction of gutta-percha.

RESULTS

The odds for developing a flare-up in teeth with a periapical radiolucency were 9.64 times greater than teeth without a periapical radiolucency (P = 0.0090). There was no statistically significant difference in flare-ups between one and two visits NSRCT. The odds of developing a flare-up increased 40 fold when NSRCT was completed in three or more visits. However, this result may have been confounded by addition of an unscheduled visit in patients suffering from flare-ups. Other independent variables did not have any statistically significant correlations.

CONCLUSIONS

A low percentage of patients experienced flare-ups during NSRCT procedures. The presence of a periapical lesion was the single most important predictor of flare-ups during NSRCT.

Assessing struvite precipitation in a pilot-scale fluidized bed crystallizer

The recovery of phosphates from biological wastewater treatment plants, through struvite crystallization, minimizes operational downtime and offers the potential for cost-effective recovery. The pilot-scale, fluidized bed reactor developed at the University of British Columbia (UBC) was found to be effective in recovering phosphate in the form of nearly pure struvite product, from an anaerobic digester centrate. The desired degree of phosphate removal was achieved by maintaining operating pH 8.0-8.2, and recycle ratio 5-9, to control the supersaturation conditions inside the reactor. The performance of the system was found to be optimal when the in-reactor supersaturation ratio was 2-6. In-reactor magnesium to phosphate molar ratio was found to be an important parameter to maintain system performance. In-reactor ammonium to phosphate molar ratio was also found to maintain a good correlation with phosphate removal. The influence of organic ligands on the struvite precipitation was investigated for a small molecular weight organic ligand, acetate, using a chemical equilibrium model PHREEQC. An acetate concentration below about 100 mg l(-1) was not found to affect the precipitation potential of struvite. Calcium and carbonate ion did not have any noticeable effect in struvite crystallization of struvite, under the operational concentrations utilized. Since the precipitation of calcium and carbonate compounds was controlled by kinetic factors, rather than thermodynamic solubility alone, the solid precipitates harvested were pure struvite, with undetectable impurities.

Admixed human embryos and stem cells: legislative, ethical and scientific advances

This paper examines the regulatory framework currently governing the creation of animal-human hybrids and chimera embryos in stem cell research, and some of the ethical implications of such research. It discusses the findings of a recent government select committee that considered the topic. It considers the debate around the precise definition of a human embryo, and whether such hybrids therefore fall within the remit of the Human Fertilisation and Embryology Authority. It outlines the advantages of such hybrids, in lessening the need for human egg donors, as well as the moral objections to species boundary violation. It calls for an examination of the scientific benefits of such research to inform debate on the question, and argues for the need to take genuine account of the public's views on this matter.

Antioxidant biofactor, a processed grain food, inhibits iron nitrilotriacetate–induced renal tumorigenesis, hyperproliferative response, and oxidative damage

We have evaluated the effect of dietary antioxidant, antioxidant biofactor (a processed grain food), on iron nitrilotriacetate–induced renal tumorigenesis, hyperproliferative response, and oxidative damage. In tumorigenesis studies, iron nitrilotriacetate alone treatment resulted in a development of 75% renal cell tumor incidence, whereas, in the group of animals fed with antioxidant biofactor diet and treated with iron nitrilotriacetate, only 43% of renal cell tumor incidence was observed. In oxidative damage studies, the decrease in the level of renal glutathione and antioxidant enzymes induced by iron nitrilotriacetate was significantly reversed by antioxidant biofactor diet pretreatment in a dose-dependent manner (18–71% recovery, P < 0.05). Antioxidant biofactor diet pretreatment also resulted in a dose-dependent inhibition (35–49% inhibition, P < 0.05) of iron nitrilotriacetate–induced lipid peroxidation as measured by thiobarbituric acid reactive substances formation in renal tissues. Similarly, in hyperproliferation studies, antioxidant biofactor diet pretreatment showed a strong inhibition of iron nitrilotriacetate–induced renal ornithine decarboxylase activity (18–54% inhibition, P < 0.05). In addition, antioxidant biofactor fed diet pretreatment also protected the kidney tissues against observed histopathological alterations. From this data, it can be concluded that antioxidant biofactor diet can abrogate the toxic and tumor promoting effects of iron nitrilotriacetate and can serve as a potent chemopreventive agent to suppress oxidant–induced tissue injury and tumorigenesis.

Vancomycin sensitivity of Staphylococcus aureus isolates from hospital patients in Karachi, Pakistan

Methicillin-resistant Staphylococcus aureus (S. aureus) (MRSA), resistant to all antibiotics including Vancomycin, has been reported in Japan, USA, Canada and Brazil. Hence, the main objective of this study was to evaluate the possible presence of Vancomycin resistant or intermediate S.aureus in Karachi. A total of 850 clinical isolates were collected from two civil hospitals in the city between February 2006 and January 2007. They were identified using standard bacteriological methods.Sensitivity to recommended antibiotics was determined by disc diffusion, agar dilution, and E-test quantitative minimum inhibitory concentration (MIC). Susceptibility to natural or semi-natural products was determined by the agar dilution method. Out of 850 isolates, 250 were MRSA, of which 22% were resistant to 4 µg/ml Vancomycin, 24% to 8 µg/ml, 15.2% to 16 µg/ml, 10% to 20 µg/ml, and 13.2% to 30 µg/ml; the remaining 15.6% were sensitive to all used concentrations. Although we did not detect any Vancomycin-resistant S. aureus (VRSA), we found that 13% of the strains were intermediates (VISA), i.e. resistant to 30 µg/ml of Vancomycin. Because of the continuously increasing prevalence of VISA, it is imperative to minimize the use of Vancomycin. Indeed, the drug should only be prescribed for the treatment of documented, culture-proven infections with MRSA that are not susceptible to routine or alternative agents. This should help avoid the consequences of the development of Vancomycin resistant S. aureus (VRSA) in our environment.

Reduced tubulin tyrosination as an early marker of mercury toxicity in differentiating N2a cells

The aims of this work were to compare the effects of methyl mercury chloride and thimerosal on neurite/process outgrowth and microtubule proteins in differentiating mouse N2a neuroblastoma and rat C6 glioma cells. Exposure for 4h to sublethal concentrations of both compounds inhibited neurite outgrowth to a similar extent in both cells lines compared to controls. In the case of N2a cells, this inhibitory effect by both compounds was associated with a fall in the reactivity of western blots of cell extracts with monoclonal antibody T1A2, which recognises C-terminally tyrosinated alpha-tubulin. By contrast, reactivity with monoclonal antibody B512 (which recognises total alpha-tubulin) was unaffected at the same time point. These findings suggest that decreased tubulin tyrosination represents a neuron-specific early marker of mercury toxicity associated with impaired neurite outgrowth.

Dairy manure and tillage effects on soil fertility and corn yields

Organic amendments have received renewed attention to improve soil fertility for crop production. A randomized complete block split plot experiment was conducted to evaluate the dairy manure (DM) amendments of soil for corn (Zea mays L. cv. Monsanto 919) production under different tillage systems. Main plot treatments were no-till (NT), conventional tillage (CT), and deep tillage (DT), and subplot treatments were chemical fertilization (DM(0)), and DM at 10Mgha(-1)yr(-1) (DM(10)) and 20Mgha(-1)yr(-1) (DM(20)) with supplemental chemical fertilization. Results show that tillage and DM had significantly reduced bulk density (rho(b)) with greater porosity (f(t)) and hydraulic conductivity (K(fs)) than soils under NT and DM(0). Manuring was effective to improve soil physical properties in all tillage treatments. While manure significantly increased C sequestration, the N concentration was influenced by both tillage and manure with significant interaction. The CT significantly increased P as did the addition of manure. However, with manure, K was significantly increased in all tillage treatments. While tilled soils produced taller plants with higher grain yields, and water-use efficiency than NT soils, manuring, in contrast, increased corn harvest index. Manure exerted significant quadratic effect on corn biomass N and K uptake. The variable effects of tillage and dairy manuring on soil properties and corn growth are most probably related to "transitional period" in which soil ecosystems may have adjusting to a new equilibrium.

Accuracy of digital rectal examination in the estimation of height of rectal lesions

BACKGROUND

To assess the accuracy of the digital rectal examination as a method of estimating the distance of a rectal lesion from the anal verge.

METHODS

One hundred doctors of variable levels of experience and from different specialities performed digital rectal examination (DRE) on a pelvic model with two fixed buttons at different levels simulating lesions in the rectum. They were asked to estimate the distance of the lesions in centimetres from the anal verge and classify the lesion as mid or low rectal.

RESULTS

Nearly half the doctors studied (45%) estimated the distance of the upper lesion accurately (7.5 cm, or within 1 cm of the correct distance), whereas 64% of the doctors estimated the distance to the lower lesion accurately (3 cm, or within 1 cm of correct distance). 93% of doctors classified the mid-rectal lesion correctly and 99% classified the lower rectal lesion correctly.

CONCLUSIONS

Though less accurate in precisely estimating the distance of a lesion from the anal verge, DRE has high accuracy in classifying rectal lesions into lower and mid-rectal lesions, irrespective of experience and background of the clinicians. It is more accurate for lower rectal lesions than mid-rectal lesions.