Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SPECIMENS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 487 records · Page 27Linked to original sources
PubMed1994

An evaluation of four methods for the detection of Pneumocystis carinii in clinical specimens.

We undertook a prospective evaluation of 4 methods for the detection of Pneumocystis carinii in clinical specimens and compared an indirect immunofluorescence assay (IFA) (Diagnostics Pasteur), and a fluorescent whitening agent (FWA) (Blankophor BA 267%, Bayer, Australia) with our standard methenamine silver (MeAg) and toluidine blue O (TB) stains. Two hundred and two specimens were received from 162 patients (133 HIV infected, 19 heart or heart-lung transplant recipients, and 10 "miscellaneous"). The specimens consisted of 132 induced sputa, 56 bronchoalveolar lavage specimens, 10 fine needle aspiration lung biopsies, and 4 pleural fluid specimens. P. carinii was detected in 44 (22%) of the specimens. The sensitivities for the detection of P. carinii pneumonia were IFA: 92% (95% CI, 83-100%), FWA: 57% (95% CI, 41-73%), MeAg: 54% (95% CI, 38-70%), and TB: 49% (95% CI, 33-65%). Discordant results were greatest in specimens from patients who were receiving specific anti-P. carinii prophylaxis, or who had received treatment for several days prior to sampling. IFA was the most sensitive test and relatively easy to perform. IFA was also the most expensive test. We found the FWA method a useful screening test as it is cheap and quick to perform. However, it is less sensitive than IFA, which should be performed on the negative specimens. With the increasing use of specific anti-P. carinii prophylaxis in HIV-infected patients, methods more specific and sensitive than MeAg and TB stains are required. We have found IFA to improve significantly the rate of detection of P. carinii in this patient group.

Evaluation Studies as Topic↗
PubMed2001

Laboratory-based surveillance for vancomycin-resistant enterococci: utility of screening stool specimens submitted for Clostridium difficile toxin assay.

OBJECTIVE: To study vancomycin-resistant enterococci (VRE) gastrointestinal colonization prevalence in high-risk hospitalized patients and to assess the cost and utility of this laboratory-based surveillance. SETTING: Large university teaching hospital. DESIGN: Quarterly prevalence culture survey of 50 stool specimens submitted for Clostridium difficile toxin A assay from October 1996 through June 1999 (n=526). Screening culture survey of all C difficile-positive stool specimens from July 1998 through June 1999 (n=140). PATIENTS: Specimens for analysis were collected from patients who were admitted to the hospital and who had C difficile toxin A testing ordered. Patient samples were excluded from analysis if they were obtained from patients not hospitalized at UCLA Medical Center, if the C difficile toxin assay result was indeterminate, or if the patient was known to have previous VRE colonization or infection. RESULTS: During quarterly surveillance, VRE was detected in 19.8%, C difficile toxin A in 9.5%, and both VRE and C difficile toxin A in 3.2% of stool specimens submitted for C difficile toxin assay. Patients whose stool specimens were positive for C difficile toxin A were significantly more likely than those whose specimens were negative to have VRE detected (odds ratio, 2.3; 95% confidence interval, 1.2-4.5). Based on these findings, in July 1998, we began routine screening of all C difficile-positive stool specimens for VRE. From July 1998 through June 1999, 58 (41.4%) of 140 patients with C difficile-positive specimens had VRE newly detected in the stool. The combined cost of the two laboratory-based surveillance strategies was approximately $62 per VRE-positive patient identified and $5,800 per year. CONCLUSION: Quarterly surveillance of stool submitted for C difficile assay combined with screening all C difficile-positive stools is a cost-effective and efficient strategy for detecting VRE stool colonization among high-risk hospitalized patients. Such a laboratory-based surveillance should be included as part of a comprehensive program to limit nosocomial VRE transmission.

Bacterial Toxins↗
PubMed1994

Detection of Mycobacterium avium-intracellulare complex in bone marrow specimens of patients with acquired immunodeficiency syndrome.

Thirty-seven bone marrow core biopsy specimens from 21 human immunodeficiency virus-infected patients with Mycobacterium avium-intracellulare complex bacteremia were stained using rabbit polyclonal antibodies against Mycobacterium bovis strain Bacillus-Calmette-Guerin (BCG) and Mycobacterium duvalii, as well as Kenyon and Fite stains, to compare sensitivities of these techniques and evaluate possible response to therapy. The patients in this study had participated in a phase I/II trial of liposome-encapsulated gentamicin therapy. Two biopsy specimens had inadequate tissue for evaluation. Thirty-two specimens demonstrated bacilli with anti-M duvalii, 33 with anti-BCG, 20 with Kenyon, and 23 with Fite. Two were negative with all stains. Fifteen biopsy specimens had epithelioid granulomas, 12 had histiocytic granulomas, and 1 had a granuloma of indeterminate type. The remaining seven biopsy specimens had no granulomas. Four of these seven demonstrated bacilli with anti-M duvalii, 5 with anti-BCG, 1 with Kenyon, and 2 with Fite. The number of M avium-intracellulare organisms per milliliter of blood decreased in 14 of 21 patients after liposome-encapsulated gentamicin therapy. However, none of the 11 patients whose pre- and post-therapy bone marrow core biopsy specimens were both evaluable demonstrated a reduction in the number of M avium-intracellulare organisms. The authors concluded that anti-M duvalii and anti-BCG are more sensitive than acid-fast stains for identifying M avium-intracellulare infection in bone marrow core biopsy specimens of patients who have acquired immunodeficiency syndrome (AIDS) with M avium-intracellulare bacteremia. Bone marrow core biopsy specimens may provide a perspective on M avium-intracellulare infection in AIDS patients that differs from the one provided by blood cultures.

Acquired Immunodeficiency Syndrome↗
PubMed1994

The spectrum of immunohistochemical staining of small-cell lung carcinoma in specimens from transbronchial and open-lung biopsies.

Immunohistochemistry is increasingly used as an aid in the diagnosis of small-cell lung carcinoma (SCLC). Previous studies have investigated immunohistochemical staining of SCLC with small numbers of antibodies, but few have examined large series with a broad panel of antibodies. For this reason, the authors examined the distribution and intensity of staining of 20 open-lung biopsy (OLB) and 21 transbronchial biopsy (TBB) specimens of SCLC with a panel of epithelial, neuroendocrine, and hormonal markers. Small-cell lung carcinoma stained most frequently with epithelial markers, followed by neuroendocrine and hormonal markers. Similar percentages of OLB and TBB specimens stained for keratin (100% each) and epithelial membrane antigen (100% and 95%, respectively). Unexpectedly, BER-EP4 stained 100% of OLB specimens. Chromogranin A was the most frequent neuroendocrine marker in OLB and TBB specimens (60% and 47%, respectively) followed by neuron-specific enolase (60% and 33%), Leu-7 (40% and 24%), and synaptophysin (5% and 19%). No neuroendocrine immunohistochemical reactivity was found in 24% of TBB specimens and 20% of OLB specimens. Bombesin was the most sensitive hormonal marker (45% of OLB specimens). These results show that keratin, epithelial membrane antigen, and BER-EP4 are reliable epithelial markers for SCLC in both TBB and OLB specimens. In addition, negative staining for neuroendocrine markers, because it can occur in as many as 25% of cases, should not deter the diagnosis of SCLC.

Biomarkers↗
PubMed1997

Comparative histologic features of liver biopsy specimens from patients coinfected with hepatitis G and C viruses with chronic hepatitis C virus alone: an age-, sex-, disease duration-, and transmission-matched controlled study of chronic hepatitis.

Hepatitis G virus (HGV) is a recently described, parenterally spread, positive-strand RNA virus of the Flaviviridae family. There is a high rate of HGV coinfection in patients with hepatitis C virus (HCV). Whether HGV can cause or is pathogenetically related to clinically apparent chronic liver disease, or whether HGV alters the course of hepatitis C in patients who are coinfected with both viruses is unknown. We studied 13 biopsy specimens from 11 patients coinfected with HGV and HCV and compared them with 15 biopsy specimens from a group of patients infected only with HCV who were matched for age, sex, disease duration, and transmission mode to characterize the histologic features of coinfected liver biopsy specimens and to look for any histologic features that might allow identification of coinfected patients. Three of the biopsy specimens from coinfected patients had a modified histologic activity index score of minimal chronic hepatitis, three of mild, two of mild/moderate, and five of moderate chronic hepatitis. Bile duct injury was absent in seven specimens, minimal in five, and mild in one. The biopsy specimens from patients who were coinfected with HGV and HCV had similar histologic features to the biopsy specimens of patients infected with HCV alone. There were no detectable histologic differences between the biopsy specimens from the two patient groups. The P values for the statistical comparisons confirmed this impression. In addition, no group of histologic features distinguished the coinfected patient group from the control group. Any suspicion that a clinician might have about the presence of HGV requires confirmation by reverse transcriptase-polymerase chain reaction testing of serum samples. Our results suggest that HGV most likely does not actively participate in the cytotoxic effects of chronic hepatitis or does so by a mechanism as yet undefined. Although HGV can cause chronic infection, the present study provides no evidence that it causes or contributes to chronic hepatitis.

Biopsy↗
PubMed2001

Predictors of Gleason pattern 4/5 prostate cancer on prostatectomy specimens: can high grade tumor be predicted preoperatively?

PURPOSE: Radical prostatectomy provides excellent cancer control in men with clinically localized prostate carcinoma. However, to our knowledge preoperative parameters for distinguishing indolent from clinically significant cancer are not well characterized. In fact, recent evidence suggests that the percent of Gleason pattern 4/5 carcinoma in the complete radical prostatectomy specimen is one of the strongest predictors of prostate cancer progression and a valid measure of cancer severity. However, it is unclear whether preoperative parameters, including biopsy Gleason pattern 4/5 carcinoma, may predict radical prostatectomy Gleason pattern 4/5 disease and, thereby, distinguish indolent from clinically significant cancer. MATERIALS AND METHODS: We prospectively obtained 101 consecutive radical prostatectomy specimens and processed them in whole mount fashion. In addition to total tumor volume, we determined tumor volume for each Gleason pattern. Biopsy tumor area was measured in a similar fashion. Univariate and multivariate analyses were performed to identify preoperative clinical and pathology parameters for predicting Gleason pattern 4/5 carcinoma on prostatectomy specimens. RESULTS: Biopsy Gleason score 7 or greater, Gleason pattern 4/5 carcinoma, perineural invasion and biopsy tumor area had statistically significant associations for identifying Gleason pattern 4/5 carcinoma on prostatectomy specimens. Logistic regression models for predicting any or greater than 10% Gleason pattern 4/5 carcinoma on prostatectomy specimens revealed that an area of pattern 4/5 disease of greater than 0.01 cm.2 on biopsy was the best single predictor with odds ratios of 15.0 (95% confidence interval 3.3 to 69.0, p = 0.0005) and 3.9 (95% confidence interval 1. 4 to 10.9, p = 0.009), respectively. For predicting any pattern 4/5 carcinoma on prostatectomy specimens a biopsy area of pattern 4/5 disease of greater than 0.01 cm.2 had only 38% sensitivity but 96% specificity. Similarly for predicting significant pattern 4/5 disease on prostatectomy specimens, defined as 10% or greater pattern 4/5, sensitivity and specificity for a biopsy area of greater than 0.01 cm.2 were 34% and 88%, respectively. Therefore, due to high false-negative rates these models had limited predictive value on an individual basis. CONCLUSIONS: Biopsy parameters such as Gleason pattern 4/5 carcinoma may provide adequate specificity for predicting clinically significant cancer, as defined by high grade Gleason patterns in the corresponding radical prostatectomy specimen. However, the accuracy of these parameters for predicting indolent cancer is limited by a prohibitive rate of false-negative findings.

Adenocarcinoma↗
PubMed1997

Use of polymerase chain reaction for the detection of Chlamydia trachomatis in ocular and nasopharyngeal specimens from infants with conjunctivitis.

BACKGROUND: Chlamydia trachomatis is the most common identifiable infectious cause of neonatal conjunctivitis. Nonculture tests including enzyme immunoassays and direct fluorescent antibody tests have been shown to perform well for the diagnosis of chlamydial conjunctivitis with sensitivities and specificities > or = 90%. However, the performance with respiratory specimens has been less than satisfactory. METHODS: We compared a new, commercially available polymerase chain reaction (PCR) assay, Roche AMPLICOR (Roche Diagnostic Systems, Branchburg, NJ) with culture for the detection of C. trachomatis in conjunctival and nasopharyngeal specimens from infants with conjunctivitis. We also evaluated AMPLICOR for the detection of C. trachomatis in the urine of mothers of positive infants. RESULTS: Ocular and nasopharyngeal specimens from 75 infants with conjunctivitis were obtained for culture and PCR. AMPLICOR was equivalent to culture for eye specimens and more sensitive than culture for nasopharyngeal specimens. The sensitivity, specificity and positive and negative predictive values of PCR compared with culture for conjunctival specimens were 92.3, 100, 100 and 98.4%, respectively. The sensitivity, specificity and positive and negative predictive values for nasopharyngeal specimens were 100, 97.2, 60 and 100%, respectively. We also detected C. trachomatis by PCR in the urine of 12 mothers of culture positive infants. CONCLUSIONS: PCR performed comparably to culture for detection of C. trachomatis in conjunctival and nasopharyngeal specimens from infants with conjunctivitis.

Bacteriological Techniques↗
PubMed1999

Radiotransparency of the triglyceride mammary prosthesis: a quantitative analysis with mastectomy specimens.

Breast cancer is the most frequent malignant tumor in women. It is estimated that 10 percent of women will present with a breast cancer during their lives. It is well known that mammography is the best technique for the early diagnosis of nonpalpable tumors, thus improving life expectancy. However, mammary prostheses may hide between 23 and 82 percent of the normal mammary tissue in mammography, and thus may delay the diagnosis of malignant mammary tumors, making prognosis worse. To solve this problem, oil-filled prostheses have been developed. In this study, 14 mastectomy specimens were used. Mammograms of the tissue pieces alone and also mammograms of the tissue pieces covering a 270-cc Trilucent prosthesis were used to verify whether the prosthesis allows observation of malignant signs in mammography. Mammograms were evaluated by an independent experienced radiologist. The following variables were studied: number of mammograms necessary to examine each specimen; kilovoltage and milliamperage necessary for each mammogram; number of microcalcification groups (malignant); number of macroscopic calcifications (benign); and rarefaction areas that were suspected for malignancy. All of these variables were measured for both mammograms for which the mastectomy specimens were covering and those for which the specimens were not covering the prothesis. Finally, the kilovoltage and milliamperage increases necessary to visualize the mammograms with mastectomy specimens covering the prosthesis were determined. Statistical analysis of the results obtained was performed. There were no significant differences in the number of mammograms (p = 0.391), the number of microcalcifications (p = 0.890), the number of macrocalcifications (p = 0.239), and finally in the presence of rarefaction areas (p = 1.000) observed in the mammograms in specimens either covering or not covering the prosthesis. However, there were significant differences (p < 0.001) between the kilovoltage and milliamperage applied to carry out the mammograms of specimens with and without the prosthesis. Thus, Trilucent prostheses allow visualization of the microscopic and macroscopic calcifications as well as rarefaction areas in mammograms. However, these mammograms required a higher kilovoltage and milliamperage compared with specimens not covering the prosthesis. To explore the whole gland, it might be necessary to perform two series of mammograms: one to detect the area shadowed by the prosthesis and one to observe the rest of the peripheral gland.

Breast Implants↗
PubMedDate not supplied

Sequential cervical specimens and the isolation of Chlamydia trachomatis: factors affecting detection.

For 260 consecutive patient visits by women to a clinic for sexually transmitted diseases, four cervical specimens were cultured in duplicate for detection of Chlamydia trachomatis. Sixty-one positive results were detected by at least one of the four specimens; the first two specimens detected 67-69% and the last two 80-82% of the 61 positives. The difference in these isolation rates is statistically significant (P = 0.003). Duplicate cultures of the same specimen did not significantly increase detection rates. A combination of two specimens could increase the number detected by 44.7% beyond the results of a single-specimen culture. Contamination rates were higher for the first two specimens. Routine cleaning of the cervical canal with a swab before the taking of specimens should reduce contamination and increase the probability of obtaining infected cells when they are present.

Cell Line↗
PubMedDate not supplied

Urine as a diagnostic specimen for the detection of Chlamydia trachomatis in Malaysia by ligase chain reaction.

BACKGROUND AND OBJECTIVES: Noninvasive urine screening for Chlamydia trachomatis infections offers a valuable public health tool, which could be of vast importance in chlamydial control programs. The authors evaluated a new DNA amplification method, ligase chain reaction (LCR). GOALS: The goal was to ascertain whether urine testing could be used as screening method to detect C. trachomatis infections in commercial sex workers, patients at sexually transmitted diseases clinic, and asymptomatic patients in Kuala Lumpur, Malaysia. METHODS: First-void urine specimens from 300 men and 300 women were tested by LCR, as well as by a commercially available enzyme immunoassay. The LCR assay amplifies specific sequences within the chlamydial plasmid with ligand-labeled probes, and the resultant amplicons are detected by an automated immunoassay. Specimens with discrepant results were confirmed by another LCR of the specimen that targeted the gene for the major outer membrane protein (OMP1). RESULTS: There were 31 LCR-positive male urine and 37 LCR-positive female urine specimens. The resolved sensitivity and specificity for the LCR of the male urine specimens were 100% and 99.6%, respectively, whereas for female urine specimens, the sensitivity and specificity were 100% and 98.5%, respectively. After resolution of discrepant test results by OMP1 LCR, the prevalence was 10% for men and 11% for women. The urine enzyme immunoassay was not useful in diagnosing C. trachomatis infections in either men or women, as the resolved sensitivities were 10% and 15.2%, respectively. The specificities were 99.6% for men and 98.9% for women. CONCLUSIONS: Testing first-void urine specimens by LCR is a highly sensitive and specific method to diagnose C. trachomatis infections in men and women, providing health care workers and public health officials with a new molecular amplification assay that uses noninvasive urine specimens for population-based screening purposes.

Chlamydia Infections↗
PubMed2003

Use of loop electrosurgical excision procedure specimens to provide tissue fractions for immunologic analyses.

OBJECTIVE: To determine if dividing loop electrosurgical excision procedure (LEEP) specimens to provide tissue for research increases rates of LEEP specimen misdiagnosis and recurrent cervical intraepithelial neoplasia. MATERIALS AND METHODS: In this chart review, 42 women with biopsy-confirmed cervical intraepithelial neoplasia (CIN) 2,3 had up to 20% of their LEEP specimens sectioned and used for immunologic analysis. The remainder of each specimen was assessed routinely. Follow-up cytologic analyses and cervical biopsies also were assessed. This cohort was compared with a control cohort of 80 patients with biopsy confirmed CIN 2,3 whose LEEP specimens were not divided. Statistical significance was defined as a p value of < .05. RESULTS: There were no statistically significant differences between the groups with regard to histologic assessment of LEEP specimens or follow-up outcomes. CONCLUSIONS: Use of up to 20% of LEEP specimens for research purposes neither adversely affects histologic evaluation of LEEP specimens nor leads to poorer follow-up outcomes.

Journal Article↗
PubMed2003

Virtual reality demonstration of surgical specimens, including links to histologic features.

The demonstration of surgical specimens, whether using 35-mm slides or digital images, tends to consist of the sequential presentation of images. Current digital technology permits a more flexible and effective way of communication, with the opportunity to more easily "navigate" between different aspects of specimens. We demonstrate a "virtual reality" method, based on QuickTime VR technology, that permits the interactive review of a complete profile of surgical specimens in the horizontal plane. Specimens were placed individually on a circular rotating platform. Thirty-six images of each specimen were captured using a digital camera, with rotation of the platform at 10 degrees intervals. The images were transferred to a computer and processed using specialized software (VRWorx). Histologic images were separately captured from tissue sections on glass slides using a digital camera mounted on a microscope. The final product is viewed using the QuickTime Viewer software application. A 360 degrees horizontal view of the specimens is achieved, with the capacity to actively rotate the specimen and to zoom in for closer review. Additionally, the user/presenter can click in predetermined "hot spots," which will open histologic images linked to those spots. This methodology, which uses readily available computer technology, helps provide a better three-dimensional understanding of surgical specimens and also a better correlation between gross and microscopic features.

Humans↗
PubMed1994

A particle counting immunoassay for the direct detection of Clostridium difficile serogroup specific antigen in faecal specimens.

The potential of a particle counting immunoassay (PACIA) for the direct detection of Clostridium difficile serogroup G specific antigen in faecal specimens was evaluated. F(ab')2 fragments from a rabbit anti-serogroup G antiserum were covalently coupled to carboxylated latex beads. This reagent was mixed with acid extracts of faecal specimens and the reaction was assayed with an optical counter which discriminated unagglutinated from agglutinated latex particles. Culture for C. difficile, faecal cytotoxin detection, PACIA and serogrouping of C. difficile isolates were performed on 249 stools. Of the 71 culture-negative specimens, none gave a positive result in the cytotoxin assay or in PACIA. Faecal cytotoxin was detected in 100 of the 178 culture-positive specimens. PACIA was positive for 63 of the 71 faecal specimens that yielded serogroup G C. difficile on culture. PACIA gave negative results for all other culture-positive stools tested with one exception, from which a serogroup A7 C. difficile strain was isolated. PACIA detection of serogroup G antigen in faecal specimens showed a sensitivity of 88.7%, a specificity of 99.7%, a predictive value of a positive culture with a serogroup G strain of 98.4%, and a predictive value for specimens that were culture-negative for a serogroup G strain of 95.6%. The results indicate that PACIA with specific antiserum is a rapid and reliable method for detecting serogroup specific antigens of C. difficile in faecal specimens. Clinical applications of the method are discussed.

Agglutination Tests↗
PubMed2006

Development and evaluation of triplex PCR for direct detection of mycobacteria in respiratory specimens.

AIMS: To develop a method for the simultaneous detection of Mycobacterium tuberculosis, Mycobacterium avium-intracellularecomplex (MAC), and other mycobacteria in clinical specimens using triplex PCR. METHODS AND RESULTS: The target of amplification was the internal transcribed spacer region between the l6S and 23S rDNA genes. Twenty-two mycobacterial type strains, 118 M. tuberculosis, 87 other mycobacteria, 75 nonmycobacterial pathogens, 115 respiratory specimens from confirmed cases of tuberculous or other mycobacterial diseases, and sputa from 50 patients with nonmycobacterial respiratory diseases were tested. In M. tuberculosis, 322 bp pan-mycobacterial and 133 bp species-specific bands were observed. In MAC, the respective bands were 322 and 84 bp. The other mycobacteria showed single pan-mycobacterial bands of approx. 300-350 bp. Nonspecific amplicons were not found in any of the nonmycobacterial pathogens. In the tuberculosis specimens, 96.4% of smear-positive specimens and 70.2% of smear-negative specimens showed positive reactions. Specimens from two patients with MAC infection were MAC positive. Only 1 of 50 specimens from nonmycobacterial diseases was positive (2.0%). CONCLUSION, SIGNIFICANCE AND IMPACT OF THE STUDY: Triplex PCR enables accurate and rapid diagnosis of tuberculosis and probably is useful for the detection of MAC and other mycobacteria in respiratory specimens.

Bronchoalveolar Lavage Fluid↗
PubMed1995

Mechanism of image formation for thick biological specimens: exit wavefront reconstruction and electron energy-loss spectroscopic imaging.

With increasing frequency, cellular organelles and nuclear structures are being investigated at high resolution using electron microscopic tomography of thick sections (0.3-1.0 microns). In order to reconstruct the structures in three dimensions accurately from the observed image intensities, it is essential to understand the relationship between the image intensity and the specimen mass density. The imaging of thick specimens is complicated by the large fraction of multiple scattering which gives rise to incoherent and partially coherent image components. Here we investigate the mechanism of image formation for thick biological specimens at 200 and 300 keV in order to resolve the coherent scattering component from the incoherent (multiple scattering) components. Two techniques were used: electron energy-loss spectroscopic imaging (ESI) and exit wavefront reconstruction using a through-focus series. Although it is commonly assumed that image formation of thick specimens is dominated by amplitude (absorption) contrast, we have found that for conventionally stained biological specimens phase contrast contributes significantly, and that at resolutions better than approximately 10 nm, superposed phase contrast dominates. It is shown that the decrease in coherent scattering with specimen thickness is directly related to the increase in multiple scattering. It is further shown that exit wavefront reconstruction can exclude the microscope aberrations as well as the multiple scattering component from the image formation. Since most of the inelastic scattering with these thick specimens is actually multiple inelastic scattering, it is demonstrated that exit wavefront reconstruction can act as a partial energy filter. By virtue of excluding the multiple scattering, the 'restored' images display enhanced contrast and resolution. These findings have direct implications for the three-dimensional reconstruction of thick biological specimens, where a simple direct relationship between image intensity and mass density was assumed, and the aberrations were left uncorrected.

Chromatin↗
PubMed1977

Adaptation of museum specimens for use in anatomical teaching aids.

Colour transparencies are prepared of a re-colourized anatomical specimen after placing labels temporarily in position to indicate specific structures. The specimen is also radiographed to show skeletal and soft tissue structures and radio-opaque materials and letters may used to indicate certain parts. Having mounted the specimen it can then be placed in a teaching carrel together with the radiographs and a back-slide projector for viewing the colour transparencies. The student is guided through an examination of the specimen using a script or soundtape. Frequent cross-reference is made between the actual specimen, the colour transparencies on which certain parts of the specimen have been labelled, and also the radiographs. The examination is followed by self-assessment questions relevant to the specimen and these may include identification of structures on a photograph of the specimen and on duplicate radiographs. In the final section of the aid, the answers of the self-assessment questions are given.

Anatomy↗
PubMed1990

Mast cells in normal and pathological specimens of the equine lung.

In lungs from 22 horses, the number and type of mast cells in histologically normal specimens were compared with those in specimens with various histological lesions. Tissues fixed in Carnoy's solution were superior to those fixed in formalin for the identification of mast cells. Fixation of lung specimens from eight horses in Carnoy's solution and formalin allowed the identification of two subpopulations of mast cells: formalin-sensitive, which predominated and formalin-resistant. Specimens with mild chronic tracheitis and mild and moderate chronic bronchitis generally had slight increases in mast cell numbers in comparison to histologically normal specimens. An increase in mast cell numbers was also observed around small and large bronchioles with mild, moderate and severe bronchiolitis and in fibrosed pulmonary pleurae in comparison to specimens with no histological lesions. The most striking increase in mast cell numbers was seen in fibrosed alveolar septa; there were approximately four times as many mast cells in these specimens as in specimens with normal histology.

Animals↗
PubMed1999

Should all stool specimens be routinely tested for Clostridium difficile?

OBJECTIVE: To determine the frequency with which Clostridium difficile was detected in stool specimens from outpatients and patients hospitalized for less than 4 days to assess the usefulness of routine laboratory screening for detecting this enteric pathogen. METHODS: Seven hundred and forty-one specimens from 398 patients were cultured over a 6-month period for Salmonella, Shigella, Yersinia, Escherichia coli O157:H7, Campylobacter and Clostridium difficile. Clostridium difficile culture-positive samples were further tested for cytotoxin production. RESULTS: Campylobacter, Salmonella, Shigella and E. coli O157:H7 were isolated in 50 (6.7%) specimens from 35 (8.8%) patients. Clostridium difficile was cultured from 88 (11.9%) specimens from 35 (8.8%) patients and its cytotoxin detected in 35 (4.7%) specimens of 12 (3%) patients. Clostridium difficile was the second most frequent enteric pathogen after Campylobacter. Of 178 (24%) specimens submitted with a specific request for Clostridium difficile testing, 13 (7.3%) were cytotoxin positive (three patients); of 563 specimens for which Clostridium difficile was not requested, 22 (3.9%) were cytotoxin positive (nine patients). CONCLUSIONS: Nine of 12 patients with cytotoxin-positive specimens would have gone undiagnosed in the laboratory had all stool samples submitted not been tested. These results suggest that Clostridium difficile disease is under-recognized and that testing all stool samples for Clostridium difficile may be warranted in our community of patients.

Journal Article↗