Search PubMed⌕ Search

Biomedical subjects

M E Boon

Publications and source records attributed to M E Boon.

At least 181 records · Page 10Linked to original sources
PubMedDate not supplied

A practical approach to routine immunostaining of paraffin sections in the microwave oven.

The Streptavidin-Biotin Complex (SABC) Immunostaining method can be carried out by performing the rinsing and blocking steps and in addition the incubation with the primary and the secondary antibody sera in the microwave oven. Irradiation of the Streptavidin-Biotin Complex reduces stain activity due to destruction of horseradish peroxidase (HRP) (Boon & Kok, 1988). Therefore, we decided not to perform this step in the microwave oven. The microwave incubations can be performed using antisera dilutions of 1:1000 (instead of 1:50) in tissue fixed with Kryofix, allowing staining in staining racks. This keeps hands-on time low and simplifies the microwave steps. It is very difficult to obtain reproducible results in the microwave oven using droplet incubations due to problems with hot spots and antenna effects. These problems are avoided when cuvettes are used and air is blown through the solutions during microwave incubations. With effective temperature control the method is highly reproducible, and takes at least 100 min less than the conventional SABC method. It is, in particular, attractive when large series of slides must be routinely immunostained and when reproducible results are desired.

Antibodies↗
PubMedDate not supplied

The use of microwave irradiation with low formalin concentrations to enhance the conversion of dopamine into norsalsolinol in rat brain: a pilot study.

The fixation of the neurotransmitter dopamine in the central nervous system by perfusion with formalin solutions seems to take place mainly via the formalin-induced condensation product norsalsolinol. In the present investigation the influence of microwave irradiation of the formalin-induced condensation of dopamine was studied in vitro and in vivo by making use of different, relatively low, formalin concentrations. It appeared that in vitro and in vivo the dopamine conversion was complete with 4% formalin and no influence of microwaves was noted. However, by making use of much lower formalin concentrations (0.2% and 0.4%) the condensation of dopamine was strongly augmented, in vitro (200%) and in vivo (at least 500%) using microwave techniques. There was a considerable loss in non-microwaved tissue (30%) after perfusion in vivo. This was lower (10%) in microwaved tissue. In experiments with perfused brain tissue which allowed a more complete calculation, a loss was found. This might be caused by a strong binding of dopamine and/or norsalsolinol to tissue components or to side reactions that could not be traced by the present experimental techniques.

Animals↗
PubMedDate not supplied

Physics of microwave technology in histochemistry.

Microwave technology has become important in preparatory techniques for microscopy in many different ways. This paper discusses various aspects of the physics of microwaves. It gives some theoretical background to understand the practical procedures. Some peculiarities in the optics of microwaves are pointed out, and the practical implications in particular of choosing the size and shape of samples and containers are discussed. Diffusion rates and chemical-reaction rates increase exponentially with temperature, so that precise temperature control is essential in most histochemical procedures. Such control is complicated by localized heating of the system, and of temperature sensors themselves, which may occur as a result of microwave irradiation.

Histocytochemistry↗
PubMedDate not supplied

The effect of heating by microwave irradiation and by conventional heating on the aldehyde concentration in aqueous glutaraldehyde solutions.

The effect of short time heating of aqueous solutions of glutaraldehyde (GA) on relative aldehyde concentration was determined using spectrophotometric analysis. Because free monomeric GA absorbs U.V. light at 280 nm, whereas the alpha, beta polymeric forms absorb at 235 nm, the purity of GA solutions can be expressed as the ratio: A 235 nm/A 280 nm (purification index, P.I.). Heating of 4 ml aliquots of 0.85% distilled aqueous GA solution resulted in an increase of the absorption at 280 nm which is correlated positively with temperature. No increase of absorption at 235 nm was found when solutions were kept at 40 degrees C for several hours. The increase of absorption at 280 nm is caused by a rapid decyclization of hemiacetals producing an increase in free aldehyde concentration. No major differences in absorption were found between the solutions heated by microwave and by conventional heating. However, because microwave irradiation is known to produce an homogeneous rise in temperature, especially in bulky samples, it is expected that the results of fixation procedures will improve by the combined effect of higher temperature and enhanced diffusion rates of the fixating species.

Aldehydes↗
PubMedDate not supplied

Candida and squamous (pre)neoplasia of immigrants and Dutch women as established in population-based cervical screening.

The objective of this study was to establish the relationship between Candida vaginalis and (pre)neoplasia and the prevalence of Candida and (pre)neoplasia related to age and ethnicity. Data were collected from 445,671 asymptomatic women invited for mass screening between 1995 and 2002 and coded according to the Dutch cervical smear coding system (KOPAC) with six grades for (pre)neoplastic changes. Prevalence and relative risks (RRs) were established for Candida and squamous abnormalities in Dutch women and four groups of immigrants. The prevalence of Candida is significantly higher in the cohort of 30-year-old women and lower in the cohorts of 45-, 50-, 55-, and 60-year-old women. The RR of having Candida was higher for Surinamese women (1.24; CI 1.08-1.42). Furthermore, the RR of having mild dysplasia was higher for Surinamese women (1.47; CI 1.14-1.89) and for women born in other countries than in The Netherlands, Turkey, and Morocco (1.36; CI 1.13-1.62). No statistically significant relationship between (pre)neoplasia and Candida was observed. C. vaginalis is more frequent among Surinamese women. Presence of Candida is not associated with an increased risk for squamous abnormalities; therefore, women carrying Candida are not at an increased risk of developing cervical cancer.

Adult↗
PubMedDate not supplied

Analysis of lifestyle data and cytologic findings in a pilot cervical screening project in rural Vietnam.

OBJECTIVE: To evaluate the possibilities of a cervical cytology screening program and the importance of lifestyle parameters in women living in rural Vietnam. STUDY DESIGN: Screening took place in Quangninh province in the north of Vietnam. From 700 women screened for the first time, smears were prepared and read by a cytotechnologist. The number of children and abortions (some women having had 10 abortions) allowed us to study the relationship of these life-style parameters with disturbed vaginal ecology (defined as the presence of Candida, trichomonads or cocci in the smear). RESULTS: The smears from farmers showed the greatest ecologic disturbances in vaginal flora. Water supply turned out to be important for coccoid overgrowth. Scores for both fungal infection and coccoid overgrowth were related to profession. Candidosis proved to be very prominent in cytologically negative smears: the organisms were found (often in abundance) in 95 of 661 negative smears but were absent from cytologically positive smears. CONCLUSION: Since only two cases of CIN 3 were found and no cases of invasive carcinoma, cervical screening for cancer ought not to be the first priority for rural Vietnam.

Abortion, Habitual↗
PubMedDate not supplied

Rescreen effect in conventional and PAPNET screening: observed in a study using material enriched with positive smears.

OBJECTIVE: To study the rescreen and PAPNET effects on enriched material derived from smears screened routinely using PAPNET and conventional microscopy. STUDY DESIGN: A series of 432 smears (containing 122 atypical squamous cells of undetermined significance [ASCUS] plus 44 at least dysplastic squamous intraepithelial lesion-positive [SIL+] ones), screened routinely with the conventional method, were rescreened using the PAPNET system. Another series of 461 smears (containing 140 ASCUS + 52 SIL+ ones) screened routinely with PAPNET were rescreened conventionally. The rescreen effect, defined as the effect of differences between the rescreen and routine screening situation, was investigated by comparing the rescreen results in both series of smears with the routine results in both series. The effect of using either method of screening was studied by comparing the PAPNET results in both series with the results of conventional screening in both series. RESULTS: The rescreen effect was statistically significant both for a higher number of smears classified as negative (less than ASCUS) and a higher number of smears classified as high grade SIL or more. PAPNET-assisted screening resulted in a significantly higher number of smears classified as high grade SIL+, although for this latter finding there is an unexplained significant difference between conventional and PAPNET-screened cases in the changes made by the cytopathologist in the cytotechnologists' diagnoses. CONCLUSION: The rescreen effect should not be ignored when enriched material is used.

Carcinoma, Squamous Cell↗
PubMedDate not supplied

Consistency of a double PAPNET scan of cervical smears.

OBJECTIVE: To determine the reproducibility and accuracy of the PAPNET system in finding and presenting abnormal and atypical cells. STUDY DESIGN: To assess the potential variation of a double PAPNET scan on the same cervical smear, 516 cervical smears from women with abnormal histologic diagnoses were scanned twice via PAPNET and reviewed by two independent examiners in a double-blind trial. RESULTS: The false negative rate of 5.7% in conventional screening was reduced to 0.4% and 0.8%, respectively, by PAPNET testing. The resulting concurrence of the first and the second PAPNET reviews was 99.2%, indicating the accuracy, sensitivity and consistency of this supplemental test. CONCLUSION: The results obtained demonstrate the reproducibility and accuracy of the system in finding and presenting abnormal and atypical cells.

Automation↗
PubMedDate not supplied

Diagnostic efficacy of endometrial cytology with the Abradul cell sampler supplemented by laser scanning confocal microscopy.

OBJECTIVE: To study the diagnostic efficacy of endometrial cytology with the Abradul cell sampler and the effect of supplementing it, in cases with overly thick smears, with laser scanning confocal microscopy. STUDY DESIGN: Sampling was performed in 1,684 women. All patients underwent subsequent histology. In eight cases with overly thick smears the original smears were restained to allow confocal microscopy. RESULTS: Efficacy was high, with 1,593 good samples. Thirty-one endometrial carcinomas were signed out as cytologically positive and 10 as atypia. In addition, 10 squamous cell carcinomas of the cervix and 1 ovarian carcinoma were diagnosed with this method. Only one case (endocervical adenocarcinoma) was not detected in the sample. In the eight cases in which confocal microscopy was performed, the images were high quality, allowing a correct diagnosis. In addition, the transition from hyperplasia to carcinoma could be visualized in the cytologic smear. CONCLUSION: Endometrial cytology in an outpatient setting is highly effective, and confocal microscopy in selected cases is not only helpful but also highly instructive.

Disposable Equipment↗
PubMedDate not supplied

Application of plastic embedding to fine needle aspiration biopsy.

OBJECTIVE: To explore the possible advantages that plastic embedding offers to fine needle aspiration biopsy (FNAB). STUDY DESIGN: A series of 54 FNABs was fixed in Kryofix (30 cases) and acetone (24 cases), plastic embedded and cut using a rotative microtome. The 2-micron sections obtained were May-Grünwald-Giemsa and Papanicolaou stain in all cases; mucicarmine, Alcian Blue, periodic acid-Schiff (PAS), PAS-diastase and Feulgen stain for DNA cytometric evaluation were also applied in five cases. Immunocytochemical staining using the antibodies cytokeratin 1-8, epithelial membrane antigen, vimentin, Ki-67, lysozime, calcitonin and carcinoembryonic antigen was carried out with the immunoalkaline phosphatase method. RESULTS: The fragments in the sections were perfectly two dimensional; the architectural features of the original tissues were preserved. Morphologic details of nuclear membranes, nucleoli and mitotic figures were excellent. Cytochemical and immunocytochemical stains were successful in all cases. Immunostains showed the precise location of the signal (nuclear, nucleolar or cytoplasmic), a clear background and preservation of morphology. CONCLUSION: Plastic embedding can be applied to FNAB to solve the problem of dense cellular groups, to study structural and cellular details, and to capitalize on the diagnostic material available for serial cytochemical, quantitative and immunocytochemical purposes.

Acetone↗
PubMedDate not supplied

Contribution of the endocervical Cytobrush sample to the diagnosis of cervical lesions.

OBJECTIVE: To compare the contribution of endocervical Cytobrush samples to wooden spatula samples in the detection of cervical preneoplastic lesions. STUDY DESIGN: Cytobrush sampling was performed on 56,120 women in conjunction with ectocervical spatula sampling, resulting in two smears per patient. Almost all women with cytologic diagnoses of high grade squamous intraepithelial lesions (CIN 3) or higher were biopsied. RESULTS: For the 221 CIN 3, the contribution of the endocervical sample was clearly more efficient, with diagnosis achieved on 98% of the endocervical samples and on 62% of the ectocervical ones. In the 674 low grade squamous epithelial lesion cases, the endocervical samples were diagnostic in 79% of cases and the ectocervical smears in 64%. Thus, endocervical sampling proved to be superior in the recognition of precancerous lesions. In 93% of the 53 squamous carcinomas, cancer cells were found in both ectocervical and endocervical samples and in 7%, exclusively in endocervical smears. In 76% of the 21 adenocarcinomas, both samples were positive, and in 23% only the endocervical sample contained cancer cells. CONCLUSION: The Cytobrush samples were more efficient in the detection of intraepithelial neoplastic lesions, suggesting that most of them originate in the endocervical epithelium. If the sampling were limited to endocervical brushing, 14% of cervical lesions would not have been detected in the smear. The prominence of preneoplastic cells in the endocervical samples might indicate that the original glandular epithelium is the major site of cervical carcinogenesis.

Adenocarcinoma↗
PubMedDate not supplied

Characteristics of false-negative smears tested in the normal screening situation.

It is common practice to rescreen false-negative (FN) smears. However, it is inevitable that this is done with some foreknowledge; at least it is known that the test smears contain one or more special cases. Therefore, we decided to test smears in the normal screening situation, when cytotechnologists are completely unaware of being tested. This experiment was done with five FNs and five true-positive (TP) smears. In a third experiment the FNs were tested with the cytotechnologists aware of their presence. Finally, 10 qualities of FNs and TPs were analyzed. In the normal screening situation, only in 1 of 25 tests was the FN recognized as malignant, while all the TPs were detected at the first testing. However, when the cytotechnologists were aware of being tested, the FN was detected in seven of eight tests. The FNs differed from the TPs in 5 of the 10 analyzed characteristics. FNs contained few (if any) large neoplastic epithelial fragments. Detached malignant cells were nearly lacking. The cancer cells had small nuclei that presented little anisokaryosis. The FNs possessed generally hypochromatic nuclei. These features explain why the malignant cells were almost never identified in the normal screening situation. We conclude that FNs and TPs differ and that it seems virtually impossible to avoid all false-negative diagnoses.

Carcinoma↗
PubMedDate not supplied

Exploiting the "toothpick effect" of the Cytobrush by plastic embedding of cervical samples.

The introduction of the combined spatula-Cytobrush sampling method has increased the diagnostic accuracy of cervical cytology. However, the smears from a small number of cases contained epithelial fragments dislodged by the "toothpick effect" of the Cytobrush. Due to their thickness, these epithelial fragments in the smears are very difficult (if not impossible) to scrutinize and are thus undiagnosable. The presence of only such fragments in smears led to false-negative diagnoses in two cases of invasive carcinoma. To solve this problem, these epithelial fragments were embedded in plastic, with thin sections prepared from the blocks. This paper presents the morphologic features and diagnostic accuracy of 77 such problem cases (found among 50,000 cases with spatula-Cytobrush smears) to which this method was applied. In almost all cases, the diagnosis on the plastic-embedded sections matched the diagnosis on the colposcopically directed biopsy. Of these 77 patients, the biopsy diagnosis showed 5 severe dysplasias, 6 carcinomas in situ, 1 squamous-cell carcinoma, 2 adenocarcinomas in situ and 2 adenocarcinomas. In addition, data are presented concerning the nuclear-size and shape-factor differences in smears versus plastic-embedded sections, and the stereologic consequences of smearing and cutting these epithelial fragments are discussed. These plastic-embedded sections are well suited for use in quantitative microscopy, as well as for diagnostic purposes.

Adenocarcinoma↗
PubMedDate not supplied

Comparison of Cytobrush sampling, spatula sampling and combined Cytobrush-spatula sampling of the uterine cervix.

Since the introduction of the Cytobrush for sampling the uterine cervix, some practitioners have ceased taking a concomitant cervical scraping using a spatula. To examine whether Cytobrush sampling alone is adequate for the diagnosis of cervical lesions, the Cytobrush and spatula samples in 444 smears (most with original diagnoses of at least mild dysplasia) were analyzed separately for the presence of diagnostic cells, endocervical cells and squamous cells. Of the 412 smears showing pathologic findings (mild to severe dysplasia or worse), diagnostic cells were present in 400 Cytobrush samples and in 369 spatula samples; the combination of both samples thus gave a 3% gain in correct diagnoses as compared to use of the Cytobrush samples alone. Another 18 smears would have been underdiagnosed based only on the Cytobrush samples. Endocervical cells were present in 95.3% of the Cytobrush samples and 83.8% of the spatula samples; squamous cells were present in 93.9% of the Cytobrush samples and 96.8% of the spatula samples. Analysis confirmed that it is important that the smear should contain both endocervical and squamous cells. A positive relationship between the absence of squamous cells in the Cytobrush sample and the probability of a false-negative assessment was suggested. It thus seems inadvisable to replace the combination sampling method by Cytobrush sampling alone, which may lead to a false-negative diagnosis.

Adult↗
PubMedDate not supplied

Polyomavirus infection versus high-grade bladder carcinoma. The importance of cytologic and comparative morphometric studies of plastic-embedded voided urine sediments.

The cytodiagnostic criteria of polyomavirus infection of the urinary tract versus high-grade bladder carcinoma in Cytospin and plastic-embedded preparations of voided urine samples are presented. In Cytospin preparations, the polyomavirus infection and the high-grade bladder carcinoma could not always be distinguished from each other. The diagnosis was facilitated when plastic-embedded specimens were used for cytologic study. On the basis of the comparison of morphometric data from the two types of specimens, it is postulated that the physical properties of the cancer cell nuclei differ from those of the virocytes.

Carcinoma↗
PubMedDate not supplied

Analysis of five sampling methods for the preparation of cervical smears.

The quality of the cervical smear, a decisive factor in the efficacy of population screening, can depend on the sampling method utilized. An analysis was made of the performance of five sample takers in a screening program, each of whom had made approximately 5,000 smears, and of the five sampling methods each had used: spatula alone (method A), Cytobrush plus spatula (method B), Cytopick (method C), cotton swab plus spatula (method D) and Cervex brush (method E). The differences between the sample takers and the sampling methods were significant in both the detection of grade III cervical intraepithelial neoplasia (CIN III) (P less than .01) and in the production of smears containing endocervical cells (EC+) (P less than .018). The data obtained firmly establish the importance of the presence of endocervical cells for smear adequacy. The results of this study indicate that (1) method B (Cytobrush plus spatula) and method C (Cytopick) give superior results in the preparation of EC+ smears and in the detection of CIN III and thus should be used in population screening programs, and (2) methods A and D should not be used for cervical cytologic sampling in such programs.

Adult↗