A fast, easy, cost-free method to remove excess dye or drug from small extracellular vesicle solution

Tracking small extracellular vesicles (sEVs), such as exosomes, requires staining them with dyes that penetrate their lipid bilayer, a process that leaves excess dye that needs to be mopped up to achieve high specificity. Current methods to remove superfluous dye have limitations, among them that they are time-intensive, carry the risk of losing sample and can require specialized equipment and materials. Here we present a fast, easy-to-use, and cost-free protocol for cleaning excess dye from stained sEV samples by adding their parental cells to the mixture to absorb the extra dye much like sponges do. Since sEVs are considered a next-generation drug delivery system, we further show the success of our approach at removing excess chemotherapeutic drug, daunorubicin, from the sEV solution.

Low-cost internal controls for detection of Giardia cysts in water samples

Giardia cysts stained with hot carbolfuchsin were used as internal controls in a concentration method for surface water samples. The morphological integrity of stained cysts and the stain's stability and intensity were tested with each of the chemical reagents used in the aluminum sulfate flocculation method. No alterations in morphology or color were noted. The stained cyst preparation has a low cost, high stability, and suitability for both light and immunofluorescent microscopy, making it affordable to researchers in low- and middle-income countries.

Simultaneous detection of intra- and inter-molecular paramagnetic relaxation enhancements in protein complexes

Paramagnetic relaxation enhancement (PRE) measurements constitute a powerful approach for detecting both permanent and transient protein-protein interactions. Typical PRE experiments require an intrinsic or engineered paramagnetic site on one of the two interacting partners; while a second, diamagnetic binding partner is labeled with stable isotopes (¹⁵N or ¹³C). Multiple paramagnetic labeled centers or reversed labeling schemes are often necessary to obtain sufficient distance restraints to model protein-protein complexes, making this approach time consuming and expensive. Here, we show a new strategy that combines a modified pulse sequence (¹H_N-Γ₂-CCLS) with an asymmetric labeling scheme to enable the detection of both intra- and inter-molecular PREs simultaneously using only one sample preparation. We applied this strategy to the non-covalent dimer of ubiquitin. Our method confirmed the previously identified binding interface for the transient di-ubiquitin complex, and at the same time, unveiled the internal structural dynamics rearrangements of ubiquitin upon interaction. In addition to reducing the cost of sample preparation and speed up PRE measurements, by detecting the intra-molecular PRE this new strategy will make it possible to measure and calibrate inter-molecular distances more accurately for both symmetric and asymmetric protein-protein complexes.

Cytomegalovirus (CMV) in gastrointestinal mucosal biopsies: should a pathologist perform CMV immunohistochemistry if the clinician requests it?

Cytomegalovirus (CMV) causes clinically significant gastrointestinal (GI) injury. CMV inclusions can be identified on routine hematoxylin and eosin (H&E) stain, but immunohistochemistry (IHC) is also available for identifying CMV in tissue. The advent of accountable care organization models of care bring into question whether it is cost-effective for immunohistochemistry to be performed upfront at the request of clinicians and whether the quality of viral detection is compromised when the diagnosis of CMV is predicated on histologic review. In this study, a retrospective review of GI biopsies with CMV evaluations was performed. There were 449 cases with clinical requests to rule out CMV and 238 CMV analyses initiated by the pathologist without a clinical request. Among the cases that included a clinician's request, 37 had CMV detected. Immunostaining was performed on 26 cases, while a diagnosis based on readily identifiable viral inclusions on H&E-stained slides was made in 11. Among pathologist-initiated work-ups, 15 were CMV+, 3 of which had inclusions identified by H&E only. Among 38 CMV cases for which IHC had been performed, 27 had overt viral inclusions obvious on H&E. Seventy-two cases revealed uninflamed GI mucosa, and although a clinical concern about CMV infection was present, a CMV IHC work-up was not initially performed; all were negative for CMV by IHC and H&E. Clinical suspicion for CMV has a high yield for CMV detection, but "upfront" testing is likely unnecessary. Careful histopathologic review by a pathologist remains critical in the efficient and cost-effective detection of CMV.

Challenges to "Classic" Esophageal Candidiasis: Looks Are Usually Deceiving

Objectives

We undertook the first case control study of histologically confirmed esophageal candidiasis (EC).

Methods

A computer search from July 2012 through February 2015 identified 1,011 esophageal specimens, including 40 cases of EC and 20 controls.

Results

The EC incidence was 5.2%; it was associated with immunosuppression and endoscopic white plaques and breaks. Smoking was a predisposing factor, and alcohol was protective. EC had no unique symptoms, and 54% of endoscopic reports did not suspect EC. Important histologic clues included superficial and detached fragments of desquamated and hyper-pink parakeratosis, acute inflammation, intraepithelial lymphocytosis, dead keratinocytes, and bacterial overgrowth. Thirty percent had no neutrophilic infiltrate. Pseudohyphae were seen on H&E in 92.5% (n = 37/40). "Upfront" periodic acid-Schiff with diastase (PAS/D) on all esophageal specimens would have generated $68,333.49 in patient charges. Our targeted PAS/D strategy resulted in $13,044.87 in patient charges (cost saving = 80.9%, $55,288.62).

Conclusions

We describe the typical morphology of EC and recommend limiting PAS/D to cases where the organisms are not readily identifiable on H&E and with at least one of the following: (1) ulcer, (2) suspicious morphology, and/or (3) clinical impression of EC.

A simple, rapid and low-cost staining method for gel-electrophoresis separated phosphoproteins via the fluorescent purpurin dye

A novel fluorescence detection method for phosphoproteins in 1-D and 2-D SDS-PAGE by using purpurin is developed in this study. Phosphoproteins as low as 4-8 ng could be specifically detected by purpurin within 60 min, and the detection limit is similar to or better than that of Pro-Q Diamond staining. Only 2 steps (staining and destaining) are needed for purpurin staining without requiring excessive fixing and washing steps, and for single use, $0.8 is enough for purpurin staining. By comprehensively comparing with Pro-Q Diamond staining, it is concluded that purpurin staining is a simple, rapid and low-cost staining method for a broad application to the research of phosphoproteins.

Detection of β-galactosidase activity: X-gal staining

X-gal staining is a rapid and convenient histochemical technique used to detect reporter gene expression. A prerequisite is the creation or acquisition of transgenic reporter mouse lines, in which the bacterial LacZ gene has been knocked into the gene of interest or placed under the control of regulatory elements corresponding to the gene of interest. Expression is marked by a dark blue stain and can be detected at the single cell level, providing a robust visual readout of gene expression in the developing kidney. Here, we describe the methodology, applications, and limitations of this technique.

A technically simple method for staining of acid-fast bacilli in cytology smears: an evaluation

OBJECTIVE

To study the effects of modifications in the Ziehl-Neelsen staining procedure on predictive accuracy for acid fast bacilli in comparison to the conventional technique. Simplicity of procedure and reagent economy were the factors taken into consideration.

DESIGN

Comparative evaluation between thick and thin air-dried smears stained conventionally and thick ethanol-fixed smears stained by the modified technique was done.

RESULTS

Positive predictive accuracy of all the three smears, that is, thick air-dried, thin air-dried and thick ethanol-fixed, was 100%. Negative predictive accuracy for thick air-dried, thin air-dried and thick ethanol-fixed smears was 36.36%, 32.33% and 34.78%, respectively. Overall predictive accuracy was 66.67% for thick air-dried, 61.90% for thin air-dried and 64.29% for thick ethanol-fixed. These differences were found to be statistically insignificant.

CONCLUSION

The modified method offers an accuracy comparable to the conventional technique, is simpler and with improved reagent economy. It is of special importance to diagnostic facilities in rural set-ups.

Papanicolaou stain: Is it economical to switch to rapid, economical, acetic acid, papanicolaou stain?

OBJECTIVE

To standardize an inexpensive and rapid Papanicolaou staining technique with limited ethanol usage.

STUDY DESIGN

Smears from 200 patients were collected (2 per patient) and fixed in methanol. Half were subjected to conventional Papanicolaou and half to stain ing with rapid, economical, acetic acid Papanicolaou (REAP) stain. In REAP, pre-OG6 and post-OG6 and post-EA36 ethanol baths were replaced by 1% acetic acid and Scott's tap water with tap water. Hematoxylin was preheated to 60 degrees C. Final dehydration was with methanol. REAP smears were compared with Papanicolaou smears for optimal cytoplasmic and nuclear staining, stain preservation, cost and turnaround time.

RESULTS

With the REAP method, cytoplasmic and nuclear staining was optimal in 181 and 192 cases, respectively. The staining time was considerably reduced, to 3 minutes, and the cost per smear was reduced to one fourth. The staining quality remained good in all the smears for > 2 years.

CONCLUSION

REAP is a rapid, cost-effective alternative to Papanicolaou stain. Though low stain penetration in large cell clusters is a limitation, final interpretation was not compromised.

Comparative analysis of the DNA staining efficiencies of different fluorescent dyes in preparative agarose gel electrophoresis

Ethidium bromide (EB) is a mutagen and toxin that is widely used in the laboratory for visualization of nucleic acids. Safer nucleic acid stains, such as SYBR Gold, SYBR Green, GoldView, GeneFinder, and GoldStar, have been developed. However, there has been no systematic comparative analysis of the staining efficiencies of these dyes. In the present study, SYBR Gold, SYBR Green I, GoldView and EB were compared. Although both SYBR Gold and SYBR Green alter electrophoretic mobility and thus DNA size estimates, they are cost-effective alternatives to EB. SYBR Gold was more sensitive than SYBR Green I at detecting short fragments, but 50-bp bands were clearly visible using either dye when visualized with a long integration time. SYBR Gold or SYBR Green I are sensitive and relatively safe alternatives to EB. In our laboratory, the SYBR Gold method is now used routinely by all members of our group with great consistency and success.

Evaluación de la tinción de Hucker para la búsqueda rutinaria de Campylobacter sp en el estudio de un síndrome diarreico agudo

Campylobacter infection is one of the most frequent causes of gastroenteritis in the world and the third in Chile according to some studies. The routinary culture for Campylobacter in our country is not performed because of its high cost, and it is known, that the Hucker stain is a reasonable screening alternative. The objective of this study was to know the utility of the Hucker stain and estimate the frequency of Campylobacter in stool samples. A total of 5,750 stool samples received in the Catholic University Health Net Microbiology Laboratories, from March 2002 to May 2004, were studied with conventional stool culture and Hucker stain. In order to validate the Hucker stain with culture, during one month, all the stool samples were also studied with Campylobacter culture, with 35% sensitivity and 100% specificity. In 115/5.750 samples (2%), curved bacilli suggesting Campylobacter were observed by Hucker stain, and another 233 enteropathogens (4%) which corresponded to: 151 Salmonella sp, 55 Shigella sp, 25 enterohemorrhagic E coli, and 2 Yersinia sp were isolated. When analyzing the patients in whom the Hucker stain was positive, 62.2% were younger than 5 years and of these, 63.8% were infants. We conclude that the Hucker stain is a simple and specific method, although not very sensitive, that allows us to increase the yield of diagnosing enteric pathogens in a 33%. Campylobacter sp was in the second place after Salmonella sp in stool samples, and most frequent in young children. The active search for Campylobacter by means of culture is fundamental in the diagnosis of acute diarrhea.

Reduced alcohol use in the staining of Pap smears: a satisfactory low-cost protocol for cervical cancer screening

OBJECTIVE

To describe a low-cost Papanicolaou staining procedure that can be applied to conventional and monolayer gynecologic preparations.

STUDY DESIGN

The amount of alcohol consumed in the procedure, which normally accounts for > 80% of the cost of processing, was reduced drastically by (1) using only 1 modified cytoplasmic counterstain (EA type), thereby (2) reducing the number of alcohol rinses by over half Orange-G dye is omitted.

RESULTS

The resultant effect of the modified staining protocol is quite satisfactory and attractive to screening eyes: nuclear details are sharp and crisp, while the cytoplasm contains transparent differential staining with blue-green and pink.

CONCLUSION

A reduction in the cost of staining should encourage cervical cancer screening, especially in developing countries, where cost is a limiting factor, thus making it possible for more women to be screened without increasing the cost of the program.

Validation of a simple and inexpensive method for the quantitation of infarct in the rat brain

A gravimetric method was evaluated as a simple, sensitive, reproducible, low-cost alternative to quantify the extent of brain infarct after occlusion of the medial cerebral artery in rats. In ether-anesthetized rats, the left medial cerebral artery was occluded for 1, 1.5 or 2 h by inserting a 4-0 nylon monofilament suture into the internal carotid artery. Twenty-four hours later, the brains were processed for histochemical triphenyltetrazolium chloride (TTC) staining and quantitation of the schemic infarct. In each TTC-stained brain section, the ischemic tissue was dissected with a scalpel and fixed in 10% formalin at 0 masculine C until its total mass could be estimated. The mass (mg) of the ischemic tissue was weighed on an analytical balance and compared to its volume (mm(3)), estimated either by plethysmometry using platinum electrodes or by computer-assisted image analysis. Infarct size as measured by the weighing method (mg), and reported as a percent (%) of the affected (left) hemisphere, correlated closely with volume (mm(3), also reported as %) estimated by computerized image analysis (r = 0.88; P < 0.001; N = 10) or by plethysmography (r = 0.97-0.98; P < 0.0001; N = 41). This degree of correlation was maintained between different experimenters. The method was also sensitive for detecting the effect of different ischemia durations on infarct size (P < 0.005; N = 23), and the effect of drug treatments in reducing the extent of brain damage (P < 0.005; N = 24). The data suggest that, in addition to being simple and low cost, the weighing method is a reliable alternative for quantifying brain infarct in animal models of stroke.

The diagnostic value and cost effectiveness of routine fungal stains in a dermatopathology service of a district general hospital

AIMS

To evaluate the use and effectiveness of fungal stains in a dermatopathology service of a district general hospital.

METHODS

A retrospective analysis of skin biopsies submitted over three years, where fungal stains were used; the results were correlated with clinical history and case notes.

RESULTS

In total, 99 cases were studied for fungi with the periodic acid Schiff stain with diastase. Fungi were present in seven cases; fungi had been suggested in the differential diagnosis of three of these cases but were an unexpected finding in four cases.

CONCLUSION

Non-specific clinical details should prompt early fungal staining and non-specific microscopic findings or inappropriate well recognised skin reaction patterns should warrant the exclusion of fungal infection. The finding of at least one case of unexpected fungal infection is justified financially and for patient best management where clinical and microscopic findings are non-specific or inappropriate.

Alternative, cost-effective fungus-staining method for control slides in cytology and histopathology

OBJECTIVE

To develop a cost-effective, reliable and safe method of providing fungal control slides for routine use in pathology laboratories.

STUDY DESIGN

A set of easily available, low-cost material was tested to obtain fungal colonies on substrate adequate for paraffin-embedded sections or smears.

RESULTS

Such material as cheese is a simple, inexpensive and practical culture medium for silver-positive fungi. A batch of paraffin blocks can be prepared to maintain a stock of control material in the laboratory.

CONCLUSION

It is useful to maintain fungal colonies to produce staining control specimens using small pieces of refrigerated cheese to easily produce silver-staining control specimens or smears embedded in paraffin, reducing the risk of accidental exposure to potentially infective pathogens in the laboratory. This method might also be a good alternative for conserving routine surgical specimens, considering the currently decreasing numbers of necropsy and large specimens, particularly from immunosuppressed and infected patients.

[Benchmarking in pathological anatomy]

Data from five different Institution of Pathological Anatomy Hospital Services are presented in order to show one (the benchmark) of the multiple existing ways to approach the budget problem and the macroeconomic management of our Services. The aim of this work is not to show the "best" way to work in terms of cost-efficacy but only a methods to compare our results with others. Nevertheless from this study is possible also to make some considerations about medical and technical workload in different services with different habits.

Detection of rubella-virus-induced apoptosis in Vero cell cultures with hematoxylin and eosin staining

In order to facilitate the detection of apoptotic cells (Apo C) in Rubella virus (RV) infected cultures in settings of low resources, we compared hematoxylin and eosin staining (H&E) with the conventional TUNEL technique, and confirmed our findings with DNA electrophoresis and transmission electron microscopy. H&E allowed to distinguish Apo C from non-apoptotic cells. The proportion of Apo C in infected cultures was proportional to the multiplicity of infection (MOI). At a MOI of 10, the percent of Apo C at 3, 4 and 5 days post infection (pi) were 26, 45 and 47%, respectively, which were significantly reduced when the caspase inhibitor z-VAD-fmk was present in the supernatant. By the TUNEL assay, the percent of Apo C in RV-infected cultures were lower (0.8, 1.2 and 1.2% at 3, 4 and 5 days pi, respectively). Our results have shown that H&E staining is an easy, rapid, economic and reproducible method to detect Apo C in RV infected Vero cells cultures. It is possible that H&E makes evident early stages of apoptosis, when an apoptotic cell shows chromatin condensation, nuclear and cytoplasmic contraction (but is still attached to the monolayer), while TUNEL detects later stages of apoptosis because it needs an extensive DNA fragmentation, when apoptotic cells are about to or have already detached from the substratum.

Fluorescent staining of glycoproteins on polyvinylidene difluoride membrane with 8-aminonaphthalene-1,3,6-trisulfonate

Here, we describe a simple and sensitive method that allows fluorescent detection of glycoproteins on polyvinylidene difluoride (PVDF) membrane. We used periodic acid oxidation of carbohydrate chains of glycoproteins and fluorescent labeling with 8-aminonaphthalene-1,3,6-trisulfonate (AN-TS) by reductive amination. We developed an additional method to enhance the ability of PVDF to absorb glycoproteins by using non-glycoprotein lectin, such as wheat germ agglutinin (WGA), as a link between the PVDF membrane and glycoproteins, resulting in considerably increased detection sensitivity to glycoproteins.

Histological identification of Helicobacter pylori: comparison of staining methods

AIM

To determine whether two recently described staining methods (the modified McMullen's and the Helicobacter pylori silver stain HpSS methods) used for the histological identification of H pylori organisms are superior to two established techniques (the modified Giemsa and anti-H pylori antibody immunostain) in terms of availability, reproducibility, rapidity, sensitivity, and cost.

METHODS

Histological sections from 63 paired gastric biopsies from adult patients previously investigated for dyspepsia were stained with the four methods and these were assessed blindly and independently by two observers. Of the 63 patients, 30 were originally negative in all tests for H pylori infection, 30 were positive, and the remaining three cases had discordant results using a combination of five tests (rapid biopsy urease test, urea breath test, culture, serology, and histology).

RESULTS

Interobserver agreement was best with the antibody method (98%), followed by the McMullen's (90%), Giemsa (87%), and HpSS (85%). Of the 60 "gold standard" positive and negative cases, 30 were positive by the modified Giemsa stain, 29 by the McMullen's method, 29 by HpSS, and 30 by the antibody stain. However, there were two false positives with the HpSS method. The modified Giemsa is the cheapest and easiest to perform technically.

CONCLUSIONS

When H pylori are present, careful examination will almost always reveal them, whichever of these stains is used. However, the modified Giemsa stain is the method of choice because it is sensitive, cheap, easy to perform, and reproducible.

Special histologic stains are rarely beneficial for the evaluation of HIV-related gastrointestinal infections

During a 28-month period, endoscopic mucosal biopsy specimens from all HIV-infected patients were submitted for routine histologic evaluation. Immunoperoxidase staining for cytomegalovirus and herpesvirus antigens (esophagus), mycobacterial and fungal staining, and Gram staining of mucosal biopsy specimens were done. Special fungal and acid-fast stains were selectively performed in patients with absolute CD4 cell counts of less than 200 cells per microliter (200 x 10(6)/L) and/or with diarrhea and or wasting syndrome. Treatment was based on the endoscopic and histologic findings, and long-term follow-up was performed. The 121 symptomatic HIV-infected patients underwent 221 upper and/or lower endoscopies with 285 biopsy sites. The sensitivity and specificity of H&E staining for the diagnosis of gastrointestinal cytomegalovirus were 97% and 100%, respectively. The results of fungal and mycobacterial stains neither altered therapy nor identified previously undiagnosed infections in any patient. Long-term follow-up revealed no patient in whom an infection was missed on routine H&E, which affected outcome. Routine H&E staining is accurate for the diagnosis of gastrointestinal opportunistic infections in HIV-infected patients. Special histologic stains for fungal, mycobacterial, and viral infections did not increase the diagnostic yield or alter medical therapy but doubled the costs.

Detection of Bordetella pertussis in a clinical laboratory by culture, polymerase chain reaction, and direct fluorescent antibody staining; accuracy, and cost

Control of Bordetella pertussis in the community is hampered by slow and insensitive diagnostic tests. We therefore examined the accuracy and cost of culture, direct fluorescent antibody (DFA) staining, and PCR in a routine clinical laboratory. Six hundred thirty seven nasopharyngeal swabs and aspirates in casamino acids transport medium were cultured, stained with polyclonal (Difco), and monoclonal (BL-5 and Accu-Mab) anti-B. pertussis reagents, and amplified by an IS481-specific PCR. PCR products were detected by a hybridization-enzyme immunoassay kit (Gen-eti-k DEIA, DiaSorin), with confirmation by a second PCR in a separate laboratory. Sensitivities and specificities of culture, polyclonal DFA, monoclonal DFA, and PCR were 36 and 100%, 11.4 and 94.6%, 8.3 and 98. 4%, and 95.0 and 99.3%, respectively, with a prevalence of 15.7%. The DFA tests were the most economical, and the PCR cost was 31% higher than culture. This study suggests that with minor improvements in economy, pertussis PCR can be implemented in a clinical laboratory with marked improvement in diagnostic accuracy.

Endoscopic biopsy pathology of Helicobacter pylori gastritis. Comparison of bacterial detection by immunohistochemistry and Genta stain

OBJECTIVES

To describe the endoscopic biopsy pathology of Helicobacter pylori gastritis, compare bacterial detection by immunohistochemistry using a specific antibody with the Genta stain, and to compare the relative costs of the 2 techniques.

DESIGN

One hundred cases of gastritis identified as positive for H pylori by Genta stain and 100 cases considered negative by the same technique were stained using an anti-H pylori-specific polyclonal antibody. Laboratory reagent and labor costs for the 2 methods were compared.

RESULTS

Chronic active gastritis with lymphoid follicles was significantly associated with H pylori infection (P <.0001). The immunohistochemical method had a sensitivity of 97% and a specificity of 98% compared with the Genta stain, with strong agreement for grading density of organisms (kappa = 0.85; P <.001). Reagent costs were similar for both methods, but immunohistochemistry using an autoimmunostainer required less dedicated technical time and hence was less expensive than the Genta stain.

CONCLUSIONS

Immunohistochemistry using a specific antibody is an accurate and cost-effective method for H pylori detection in gastric biopsies.

Relative value and cost-effectiveness of culture and special stains in fine needle aspirates of the lung

OBJECTIVE

To define the role of microbiologic stains and culture in lung fine needle aspiration (FNA) specimens.

STUDY DESIGN

All lung FNA specimens over a nine-year period, with results of both culture and microbiologic stains (Gram's, methenamine silver and acid fast) were reviewed and correlated with clinical information.

RESULTS

Sixty-five cases were identified; 13 cases represented clinically significant infections (20%). Gram's stain identified 3 infections and had 1 false positive result, while culture identified 7 infections and had 9 false positive results. However, all false positive cultures represented easily identifiable contaminants, and eight of nine cases had no associated acute inflammation or necrosis. Aspergillus species were detected in four cases by Papanicolaou and silver stain, while culture was positive in only one case. Coccidioides immitis was detected by both Papanicolaou stain and culture in one case. A single case of Mycobacterium tuberculosis was identified by both culture and acid-fast stain. While culture appeared more cost-effective than Gram's stain for identifying bacteria, both Papanicolaou and methenamine silver stain were more cost-effective for identifying fungi.

CONCLUSION

In lung FNA specimens, culture and special stains should be restricted to specimens with acute inflammation or necrosis. Gram's stain and fungal culture are insensitive and not cost-effective, and fungi are often identifiable with routine stains.

Gram stain method shows better sensitivity than clinical criteria for detection of bacterial vaginosis in surveillance of pregnant, low-income women in a clinical setting

OBJECTIVE

The purpose of the study is to determine whether the Gram stain method is superior to the clinical criteria for the diagnosis of bacterial vaginosis in low-income pregnant women seen in a resident clinic setting. The clinical criteria is the current diagnostic method employed to diagnose bacterial vaginosis.

STUDY DESIGN

In this study, 51 pregnant women with vaginal discharge were prospectively evaluated. All were screened using the clinical criteria, Gram stain method, and culture of the discharge. The modified scoring system instituted by Nugent et al. (J Clin Microbiol 29:297-301, 1991) was employed in reading the Gram stain smears. The clinical criteria were then compared with the Gram stain method. Isolation of moderate to many Gardnerella vaginalis growth by culture was used as the confirmatory finding.

RESULTS

Sensitivity of the Gram stain method (91%) was significantly higher than that of the clinical criteria (46%), (sign test P = 0.0023, < 0.01). The Gram stain method also has both a low false-negative (4%) and high negative predictive value (96%), making it an ideal diagnostic test.

CONCLUSION

The Gram stain method is a rapid and cost-effective test that is also highly reproducible and readily available in many laboratories. These features make the Gram stain method a more desirable screening procedure for bacterial vaginosis in a clinic population.

Gram stain method shows better sensitivity than clinical criteria for detection of bacterial vaginosis in surveillance of pregnant, low-income women in a clinical setting

OBJECTIVE

The purpose of the study is to determine whether the Gram stain method is superior to the clinical criteria for the diagnosis of bacterial vaginosis in low-income pregnant women seen in a resident clinic setting. The clinical criteria is the current diagnostic method employed to diagnose bacterial vaginosis.

STUDY DESIGN

In this study, 51 pregnant women with vaginal discharge were prospectively evaluated. All were screened using the clinical criteria, Gram stain method, and culture of the discharge. The modified scoring system instituted by Nugent et al. (J Clin Microbiol 29:297-301, 1991) was employed in reading the Gram stain smears. The clinical criteria were then compared with the Gram stain method. Isolation of moderate to many Gardnerella vaginalis growth by culture was used as the confirmatory finding.

RESULTS

Sensitivity of the Gram stain method (91%) was significantly higher than that of the clinical criteria (46%), (sign test P = 0.0023, < 0.01). The Gram stain method also has both a low false-negative (4%) and high negative predictive value (96%), making it an ideal diagnostic test.

CONCLUSION

The Gram stain method is a rapid and cost-effective test that is also highly reproducible and readily available in many laboratories. These features make the Gram stain method a more desirable screening procedure for bacterial vaginosis in a clinic population.

Staining system: a cheap and simple way for staining ultrathin sections

A staining device for sectioned material supported on grids for viewing at the Transmission Electron Microscope is described. The method based in a double side sticky tape is inexpensive, rapid and clean. By using only pipettes and a double side sticky tape the best solution to the tedious problems of sections staining is obtained. The tape is discarded and the staining solution too. Precipitates have not been observed.

Comparison of Gram stain with DNA probe for detection of Neisseria gonorrhoeae in urethras of symptomatic males

The comparison of Gram-stained urethral smears with Gen-Probe for the detection of Neisseria Gonorrhoeae in the urethras of males with symptomatic urethritis revealed a 99.6% correlation between the two methods. A simple Gram stain would appear to be the method of choice for the detection of gonorrhea in symptomatic males, because it is much less expensive and much more rapid than the Gen-Probe method.

Utility of Gomori methenamine silver stains in bronchoalveolar lavage specimens

Bronchoalveolar lavage (BAL) with Gomori methenamine silver (GMS) stain is commonly used to detect Pneumocystis carinii and fungal organisms as causes of infectious pulmonic disease in immunosuppressed patients. However, several reports have indicated that GMS stains are not any more sensitive than conventional cytologic stains in detecting Pneumocystis organisms in select patient populations, such as those with acquired immunodeficiency syndrome (AIDS). To examine the utility of GMS stains in our laboratory, we retrospectively reviewed 243 BALs from 188 patients. Sensitivity of the GMS stain for Pneumocystis and for fungi detection was 100%. Sensitivity for Pneumocystis and for fungi detection by Papanicolaou stain alone was 79% and 88%, respectively; by Diff-Quik stain alone it was 68% and 88%, respectively; and by combined Papanicolaou and Diff-Quik stains it was 79% and 100%, respectively. In four additional cases, fungi were detected by other methods (culture, biopsy) and not by BAL. The GMS stain result was correlated with a number of risk variables to determine which variables were associated with GMS positivity. Using stepwise logistic regression, Pneumocystis positivity by GMS stain correlated (P < 0.0001) only with the variable of history of AIDS or AIDS risk factors. Fungal organism positivity by GMS stain correlated (P = 0.02) only with the variable of history of BAL positivity for fungus. Cost savings analyses were performed, estimating the cost of the GMS stain at $45 (total cost of GMS in 243 BALs was $10,935).(ABSTRACT TRUNCATED AT 250 WORDS)

Helicobacter pylori detection: a quality and cost analysis

Histopathologic interpretation of hematoxylin and eosin (H&E)-stained endoscopic biopsies is a common method for identifying Helicobacter pylori. Few studies report the accuracy of this method, and none have compared costs of other diagnostic methods. In the clinical setting of a community hospital using standard diagnostic techniques, the purpose of this study were to determine 1) the comparative sensitivities and specificities of the H&E stain, the Warthin-Starry silver stain, the Giemsa stain, and the CLOtest; 2) the sensitivity and specificity of an "experienced" pathologist in identifying H. pylori by H&E stains, compared with a rotating pathology faculty; and 3) the time to diagnosis (turnaround time) and current patient charges for each diagnostic method. Bacterial identification by the silver stain (or a combination of other tests which were likely to compensate for false-positive and false-negative silver stains) were used as the diagnostic standard in evaluating 94 consecutive cases with the following results: The H&E stain interpreted by the rotating pathology staff was the least sensitive method and one of the least specific tests that were studied. The silver and Giemsa stains were equally sensitive in identifying H. pylori; the silver stain was more specific. The CLOtest was less sensitive than the silver and Giemsa stains, but was equally specific. CLOtest was similar in sensitivity to the H&E stain examined by the "experienced" pathologist, but was more specific. An experienced pathologist was significantly more sensitive than the rotating pathologists in evaluating H&E-stained slides. Therefore, if H&E stains are used to identify H. pylori, which is a common practice, it may be advantageous to use an experienced pathologist. The CLOtest was a simple, rapid, and cost effective substitute for H&E stains in the identification of H. pylori.

Immunohistochemical determination of estrogen and progesterone receptor status in breast cancer

Immunohistochemical staining of fresh frozen tissue to identify estrogen and progesterone receptors was tested as a means to supplant the dextran-coated charcoal assay in a small community hospital. Forty-three tumors were compared, yielding an overall concordance of 88% between immunohistochemical staining and the dextran-coated charcoal assay for determination of combined estrogen/progesterone receptor status. In addition, there was greater than 70% concordance for semiquantitative grades. Staining also revealed many other advantages, such as a 65% reduction in costs. For these reasons, the authors have abandoned the dextran-coated charcoal assay in favor of staining for estrogen/progesterone receptor status.

Comparison of four methods for rapid detection of Pneumocystis carinii in respiratory specimens

Four stains for the detection of Pneumocystis carinii in respiratory specimens were compared for sensitivity, specificity, preparation time, and ease of interpretation. One hundred specimens were collected. Of these, 50 were induced sputum specimens and 50 were bronchoalveolar lavage fluid. All specimens were stained with Diff-Quik (DQ) (a modified Giemsa stain), a quick silver stain, and direct and indirect immunofluorescence stains. A positive specimen was defined as any smear positive by two or more of the methods. Fifty-eight percent of specimens were positive. Seventy-four percent of the sputum specimens and 42% of the bronchoalveolar lavages were positive. The sensitivities for detection of P. carinii in sputum were 92% with silver stain, 97% with direct immunofluorescence assay (DFA), 97% with indirect immunofluorescence assay (IFA), and 92% with DQ. The sensitivities for detection in bronchoalveolar lavage were 86% with silver stain, 90% with DFA, 86% with IFA, and 81% with DQ. Preparation times varied from 90 min for the silver stain and IFA to 3 min for DQ. Costs of the tests varied from $1.50 per slide for DQ to $10.00 per slide for the silver stain and DFA. Reading times varied from 10 to 30 min for the silver stain and DQ to less than 5 min for the immunofluorescence assays. We conclude that all of these tests are viable options for the clinical laboratory, and the choice will be influenced by factors such as clinical volume, ability to batch specimens, and expertise of technological support. A reasonable option may be to use the quick and inexpensive DQ as a screening test and to confirm negative smears with a more sensitive assay.