scholarly journals New sequential touch method for determining bacterial contact transfer rate from finger to surface

2018 ◽  
Author(s):  
Pengcheng Zhao ◽  
Yuguo Li
Keyword(s):  
Transfer Rate ◽  
Goodness Of Fit ◽  
Petri Dish ◽  
New Method ◽  
Random Errors ◽  
Surface Sampling ◽  
Glass Slides ◽  
Significant Difference ◽  
Sterile Petri Dish

ABSTRACTBacteria can be transferred via surface touch. To evaluate the transfer rate, traditional single-touch methods require measuring the number of bacteria on donor and recipient surfaces, which is typically characterized by high levels of uncertainty. In this study, two concentrations ofStaphylococcus aureusATCC 25923 were inoculated on a clean thumb. For each set of trials, sequential touches were made between the thumb and each of 30 sterile glass slides, and each slide was placed in a sterile petri dish. The transferred bacteria on each slide were directly cultured in situ, and the colony-forming units (CFUs) were counted. The bacterial contact transfer rate was calculated by fitting the series of CFUs with the formula established. The average transfer rate was 12.9% under these conditions. The goodness of fit was compared in terms of the number of slides used in a set of trials and the number of CFUs counted on the slides. The use of more slides in a set of trials allowed more accurate evaluation of the transfer rate. The use of fewer than 20 slides was unacceptable. The high density of CFUs on the slides made counting them difficult, but if fewer than five CFUs were counted in a set of trials, the fit would be significantly influenced. To further evaluate the method, the dermal resident microflora on the thumb were also used to perform contact transfer tests. No statistically significant difference was found in the estimated transfer rate between the standard strain and the resident microflora.IMPORTANCEDiseases can be transferred indoors via the surface route because bacteria and viruses can be transferred to and from the hands when a fomite is touched. Various methods have been used to estimate the bacterial contact transfer rate between hands and surfaces. Evaluated transfer rates have had significant deviations and varied significantly across studies, partially due to the use of the single hand-surface touch method, inefficient hand/surface sampling, and complicated bacteria culture.In this study, the bacterial contact transfer rate was evaluated with a new method involving sequential touches between a donor and a series of recipients. The bacteria on the recipients were cultured in situ without hand/surface sampling, which simplified the process of surface bacteria quantification. The new method significantly reduces experimental complexity, decreases random errors in the data, and provides a new method for understanding microbial transfers between surfaces.

Rotary Beveling for In Situ Thin-Section Microscopy of Cell Cultures

1981 ◽  
Vol 39 ◽  
pp. 550-551
Author(s):  
Dean A. Handley ◽  
Jack T. Alexander ◽  
Shu Chien
Keyword(s):  
Cell Growth ◽  
Cell Cultures ◽  
Molecular Interactions ◽  
Convenient Method ◽  
Petri Dish ◽  
Simple Method ◽  
Thin Section Microscopy ◽  
Thin Sectioning ◽  
Organic Fluids

In situ preparation of cell cultures for ultrastructural investigations is a convenient method by which fixation, dehydration and embedment are carried out in the culture petri dish. The in situ method offers the advantage of preserving the native orientation of cell-cell interactions, junctional regions and overlapping configurations. In order to section after embedment, the petri dish is usually separated from the polymerized resin by either differential cryo-contraction or solvation in organic fluids. The remaining resin block must be re-embedded before sectioning. Although removal of the petri dish may not disrupt the native cellular geometry, it does sacrifice what is now recognized as an important characteristic of cell growth: cell-substratum molecular interactions. To preserve the topographic cell-substratum relationship, we developed a simple method of tapered rotary beveling to reduce the petri dish thickness to a dimension suitable for direct thin sectioning.

Detection of atrial natriuretic peptides (ANP) in rat atria by immunogold-silver staining (IGSS)

1994 ◽  
Vol 52 ◽  
pp. 304-305
Author(s):  
Robyn Rufner ◽  
Gerhard W. Hacker ◽  
Michele Forte ◽  
Nancyleigh E. Carson ◽  
Cristina Xenachis ◽  
...  
Keyword(s):  
Natriuretic Peptides ◽  
Silver Staining ◽  
Sodium Thiosulfate ◽  
Atrial Natriuretic Peptides ◽  
Paraffin Sections ◽  
Glass Slides ◽  
Metallic Salts ◽  
Wistar Kyoto ◽  
Right Atria

The use of immunogold-silver staining (IGSS) to enhance label penetration and Localization for immunocytochemistry or in situ hybridization utilizing a variety of metallic salts has been documented. In this morphological study, the effects of silver acetate, silver lactate and silver nitrate were evaluated for immunogold-labeling of a trial natriuretic peptides (ANP) in rat right atria.Eight Wistar Kyoto retired breeders were sedated with pentobarbital, perfused with either 4% paraformaldehyde (LM) or Karnovsky's fixative (EM), and right atria were dissected, processed, embedded in paraffin or epon, respectively and sectioned according to conventional methods. For light microscopy, an indirect IGSS method according to Hacker (3) was performed. Paraffin sections on glass slides were washed in ddH2O, immersed in Lugol's iodine, washed in ddH2O and treated with 2.5% aqueous sodium thiosulfate for 20 sec. After additional washes in ddH2O and TBS-0.1% fish gelatin, 10% normal goat serum (PBS with 1% BSA) was applied for 20 min before an overnight incubation at 4°C with a polyclonal α-ANP primary antibody (Peninsula Labs, 1:1000 in TBS/BSA).

LABORATORY TESTS OF THYROID FUNCTION IN HYPERTHYROIDISM II.

1969 ◽  
Vol 62 (4_Suppla) ◽  
pp. S23-S35
Author(s):  
B.-A. Lamberg ◽  
O. P. Heinonen ◽  
K. Liewendahl ◽  
G. Kvist ◽  
M. Viherkoski ◽  
...  
Keyword(s):  
Thyroid Function ◽  
Laboratory Tests ◽  
Goodness Of Fit ◽  
Point Of View ◽  
Accurate Estimation ◽  
Diagnostic Efficiency ◽  
Normal Limits ◽  
Significant Difference ◽  
Crossing Point ◽  
Hyperthyroid Patients

ABSTRACT The distributions of 13 variables based on 10 laboratory tests measuring thyroid function were studied in euthyroid controls and in patients with toxic diffuse or toxic multinodular goitre. Density functions were fitted to the empirical data and the goodness of fit was evaluated by the use of the χ2-test. In a few instances there was a significant difference but the material available was in some respects too small to allow a very accurate estimation. The normal limits for each variable was defined by the 2.5 and 97.5 percentiles. It appears that in some instances these limits are too rigorous from the practical point of view. It is emphasized that the crossing point of the functions for euthyroid controls and hyperthyroid patients may be a better limit to use. In a preliminary analysis of the diagnostic efficiency the variables of total or free hormone concentration in the blood proved clearily superior to all other variables.

Increse of newly - detected in situ cancers in non-palpable breast lesions

2006 ◽  
Vol 53 (1) ◽  
pp. 73-75
Author(s):  
N. Miletic ◽  
D. Stojiljkovic ◽  
M. Inic ◽  
M. Prekajski ◽  
A. Celebic ◽  
...  
Keyword(s):  
Breast Tissue ◽  
Malignant Disease ◽  
Clinical Stage ◽  
Diagnostic Procedures ◽  
Basal Membrane ◽  
Needle Aspiration ◽  
Screening Mammography ◽  
Significant Difference ◽  
Malignant Lesions

Great importance in detecting cancer in the phase of in situ lays in the fact that the epithelial layer is deprived of blood and lymph vessels, so metastases may develop only when basal membrane has been broken. This paper includes 46 operated women in whom it preoperatively had been verified suspect non-palpable lesion. The preoperative diagnostics included use of high- resolution mammography, aimed mammography, palpatory examination, as well as fine-needle aspiration (FNA), biopsy and cytologic analysis of the sample. The methodology of this work implies the use of stereotaxic marking, specimen mammography and ex-tempore pathohistology analysis. Out of 46 investigated patients in clinical stage T0N0M0, in whom there were no signs of malignant disease, and according to suspect lesion of initial screening mammography, malignant lesions of breast tissue were diagnosed in 19 patients (41%) intraoperatively. Three of these lesions (15,8%) were histopathologically verified as in situ. Comparing our results with data of the Institute of oncology and radiology of Serbia hospital registry (IORS) for the year 2001, from 1173 patients registered with malignant lesions, only 16 ones (1,4%) had in situ cancer, operated on the basis of the suspect mammography of clinical stage T0N0M0. Statistically significant difference was found related to the number of detected cancers in this early phase of the breast malignant disease. This limits surgical intervention to tumorectomy, with preservation of the remaining breast tissue, what brings to healing, justifying in that way, screening examinations and routine application of the most contemporary diagnostic procedures.

A new method for the in situ assay of α-glucosidase activity and inhibitor screening through an enzyme substrate-mediated DNA hybridization chain reaction

2019 ◽  
Vol 43 (24) ◽  
pp. 9458-9465
Author(s):  
Xiquan Yue ◽  
Lihong Su ◽  
Xu Chen ◽  
Junfeng Liu ◽  
Longpo Zheng ◽  
...  
Keyword(s):  
Small Molecule ◽  
Dna Hybridization ◽  
New Method ◽  
Hybridization Chain Reaction ◽  
Chain Reaction ◽  
Inhibitor Screening ◽  
Glucosidase Activity ◽  
Enzyme Substrate ◽  
In Situ Assay

The strategy is based on small molecule-mediated hybridization chain reaction.

scholarly journals SMILE and Wavefront-Guided LASIK Out-Compete Other Refractive Surgeries in Ameliorating the Induction of High-Order Aberrations in Anterior Corneal Surface

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Min-jie Ye ◽  
Cai-yuan Liu ◽  
Rong-feng Liao ◽  
Zheng-yu Gu ◽  
Bing-ying Zhao ◽  
...  
Keyword(s):  
Spherical Aberration ◽  
Laser In Situ Keratomileusis ◽  
Small Incision Lenticule Extraction ◽  
Corneal Surface ◽  
Small Incision ◽  
Significant Difference ◽  
Lenticule Extraction ◽  
A Prospective Study ◽  
High Order Aberrations

Purpose. To compare the change of anterior corneal higher-order aberrations (HOAs) after laser in situ keratomileusis (LASIK), wavefront-guided LASIK with iris registration (WF-LASIK), femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK), and small incision lenticule extraction (SMILE).Methods. In a prospective study, 82 eyes underwent LASIK, 119 eyes underwent WF-LASIK, 88 eyes underwent FS-LASIK, and 170 eyes underwent SMILE surgery. HOAs were measured with Pentacam device preoperatively and 6 months after surgery. The aberrations were described as Zernike polynomials, and analysis focused on total HOAs, spherical aberration (SA), horizontal coma, and vertical coma over 6 mm diameter central corneal zone.Results. Six months postoperatively, all procedures result in increase of anterior corneal total HOAs and SA. There were no significant differences in the induced HOAs between LASIK and FS-LASIK, while SMILE induced fewer total HOAs and SA compared with LASIK and FS-LASIK. Similarly, WF-LASIK also induced less total HOAs than LASIK and FS-LASIK, but only fewer SA than FS-LASIK (P<0.05). No significant difference could be detected in the induced total HOAs and SA between SMILE and WF-LASIK, whereas SMILE induced more horizontal coma and vertical coma compared with WF-LASIK (P<0.05).Conclusion. FS-LASIK and LASIK induced comparable anterior corneal HOAs. Compared to LASIK and FS-LASIK, both SMILE and WF-LASIK showed advantages in inducing less total HOAs. In addition, SMILE also possesses better ability to reduce the induction of SA in comparison with LASIK and FS-LASIK. However, SMILE induced more horizontal coma and vertical coma compared with WF-LASIK, indicating that the centration of SMILE procedure is probably less precise than WF-LASIK.

Verification of In Situ Thresholds and Integrated Real-Ear Measurements

2010 ◽  
Vol 21 (10) ◽  
pp. 663-670 ◽  
Author(s):  
Jeffrey J. DiGiovanni ◽  
Ryan M. Pratt
Keyword(s):  
Measurement System ◽  
Hearing Aids ◽  
Hearing Aid ◽  
Normal Hearing ◽  
Analysis Tool ◽  
Ohio University ◽  
Positive Direction ◽  
Significant Difference ◽  
Threshold Measurement

Background: Accurate prescriptive gain results in a more accurate fit, lower return rate in hearing aids, and increased patient satisfaction. In situ threshold measurements can be used to determine required gain. The Widex Corporation uses an in situ threshold measurement strategy, called the Sensogram. Real-ear measurements determine if prescriptive gain targets have been achieved. Starkey Laboratories introduced an integrated real-ear measurement system in their hearing aids. Purpose: To determine whether the responses obtained using the Widex Sensogram were equivalent to those obtained using current clinical threshold measurement methods. To determine the accuracy of the Starkey IREMS™ (Integrated Real Ear Measurement System) in measuring RECD (real-ear to coupler difference) values compared to a dedicated real-ear measurement system. Research Design: A verification design was employed by comparing participant data measured from standard, benchmark equipment and procedures against new techniques offered by hearing-aid manufacturers. Study Sample: A total of 20 participants participated in this study. Ten participants with sensorineural hearing loss were recruited from the Ohio University Hearing, Speech, and Language Clinic participated in the first experiment. Ten participants with normal hearing were recruited from the student population at Ohio University participated in both experiments. The normal-hearing group had thresholds of 15 dB HL or better at the octave frequencies of 250–8000 Hz. The hearing-impaired group had thresholds of varying degrees and configurations with thresholds equal to or poorer than 25 dB HL three-frequency pure-tone average. Data Collection and Analysis: The order of measurement method for both experiments was counterbalanced. In Experiment 1, thresholds obtained via the Widex Sensogram were compared to thresholds obtained for each participant using a clinical audiometer and ER-3A insert ear phones. In Experiment 2, RECD values obtained via the Starkey IREMS were compared to RECD values obtained via the Audioscan Verifit™. A repeated-measures analysis of variance (ANOVA) was used for statistical analysis, and a Fisher's LSD (least significant difference) was used as a post hoc analysis tool. Results: A significant difference between Sensogram thresholds and conventional audiometric thresholds was found with the Sensogram method resulting in better threshold values at 0.5, 1.0, and 2.0 kHz for both groups. In Experiment 2, a significant difference between RECD values obtained by the Starkey IREMS and the Audioscan Verifit system was found with significant differences in RECD values found at 0.25, 0.5, 0.75, 1.5, 2.0, and 6.0 kHz. Conclusions: The Sensogram data differ significantly from traditional audiometry at several frequencies important for speech intelligibility. Real-ear measures are still required for verification of prescribed gain, however, calling into question any claims of shortened fitting time. The Starkey IREMS does perform real-ear measurements that vary significantly from benchmark equipment. These technologies represent a positive direction in prescribing accurate gain during hearing-aid fittings, but a stand-alone system is still the preferred method for real-ear measurements in hearing-aid fittings.

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