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PubMed1982

Combined light and electron microscope in routine histopathology.

We report our experience with a prototype combined light and electron microscope (the LEM 2000) with particular reference to its application to routine surgical histopathology. We found its major advantages over conventional transmission electron microscopies were due to the large grid size (7 mm diameter), low magnification capacity (x 250), and the built-in microprocessor for recording areas of interest. These features combine to reduce sampling errors and greatly facilitate orientation and relocation of fields of diagnostic importance.

Histological Techniques↗

PubMed1987

Reassessment of faecal alpha-1-antitrypsin excretion for use as screening test for intestinal protein loss.

Faecal alpha-1-antitrypsin and 51Cr-albumin losses in 42 patients with either gastrointestinal or hepatic disease were compared. The reference range was derived from measurements in 20 controls without gastrointestinal disease. Alpha-1-antitrypsin excretion was increased in patients with excessive 51Cr-albumin loss, and correlations were found between alpha-1-antitrypsin clearance and 51Cr-albumin excretion. Because of the considerable overlap of faecal alpha-1-antitrypsin excretion between controls and patients, sensitivity and specificity of the test were only 58% and 80%, respectively. This poor reliability could not be explained by sampling error or temporal variations in alpha-1-antitrypsin excretion. These results show that although faecal alpha-1-antitrypsin excretion correlates with 51Cr-albumin excretion when whole groups of patients are studied, its poor sensitivity makes it an unreliable measure of enteric protein loss.

Albumins↗

PubMed1987

Immunohistology of oestrogen receptor and D5 antigen in breast cancer: correlation with oestrogen receptor content of adjacent cryostat sections assayed by radioligand binding and enzyme immunoassay.

Two monoclonal antibodies recognising epitopes associated with oestrogen receptor protein were evaluated against the assayable soluble oestrogen receptor concentration in a series of 149 breast carcinomas. One antibody (anti-ER) recognises the hormone binding unit of oestrogen receptor and gives nuclear staining; the other antibody (anti-D5) was raised to a component of soluble oestrogen receptor and gives cytoplasmic staining. To minimise variations attributable to tumour heterogeneity and sampling error immunohistology using the two monoclonal antibodies, radioligand binding assays, enzyme immunoassays, and quantitative histology were done on adjacent frozen sections. Thirty nine per cent, 48%, 54%, and 43% of the tumours were found to be oestrogen receptor positive by radioligand binding assay, anti-ER and anti-D5 immunohistology, and enzyme immunoassay, respectively. Strong correlations (p less than 0.0005) were found between anti-ER immunohistology and the radioligand binding assay. Only weak correlations were found between anti-D5 immunohistology and the results of other assay methods for oestrogen receptor. Nuclear staining of human breast cancers with the anti-ER monoclonal antibody thus seems to be an acceptable alternative to biochemical assays, with the additional advantage of showing intercellular and regional heterogeneity for oestrogen receptor content.

Adenocarcinoma↗

PubMed1988

Extraction of DNA from small sections of frozen tissue with simultaneous histological examination.

Though analysis of small sections of biopsy material by molecular techniques permits increased sensitivity, it also requires accurate histological examination of the tissue in order to reduce sampling error. A technique for the extraction of DNA from small sections of frozen biopsy material with simultaneous histological examination from adjacent sections is described that may enhance the accuracy of characterisation of the tissue, particularly where there is focal variation. The quality of the DNA obtained enables a full range of molecular studies to be carried out.

Biopsy↗

PubMed1990

Demonstration of progesterone receptors in paraffin wax sections of breast carcinoma.

Several immunohistological methods for the demonstration of progesterone receptors were tried on routinely processed paraffin wax sections of breast carcinoma, using Abbott's PgR-ICA monoclonal antibody. The best results were obtained with the avidin-biotin-immunoperoxidase complex method with no prior trypsinisation or DNAse digestion, and with imidazole added to the final diaminobenzidine developing solution. A simple semiquantitative scoring system was used to assess the staining results which were then compared with the results obtained by a standard dextran-coated charcoal biochemical assay. Of 31 cases examined, the results of the two methods were concordant in 25 (81%) of cases. This is near the higher end of the concordance range obtained by several other authors using frozen sections. The discordance encountered in a few cases was possibly the result of sampling errors which are more likely to occur with the chemical rather than the histological method. It is concluded that the method described here is fairly reliable and would greatly simplify the process of assessment of progesterone receptors in breast, and possibly other tumours.

Breast Neoplasms↗

PubMed1991

Prognostic value of proliferating cell nuclear antigen in gastric carcinoma.

A new monoclonal antibody to proliferating cell nuclear antigen (PCNA), PC10, which can be used on routinely processed tissue, was applied to 93 cases of gastric carcinoma. Significant intra-tumoural variation in staining occurred. In addition to a PCNA index (percentage of positive cells per 1000 tumour cells), a semiquantitative PCNA grading system was devised, based on estimates of less than or more than 50% of positive tumour cells in whole sections. Neither PCNA index nor PCNA grade showed any correlation with established histological variables, tumour stage, or the presence of lymph node metastases. No significant correlation was observed between PCNA index and S + G2M phase fraction measured by flow cytometric analysis. To analyse survival tumours with PCNA indices above and below the median level (41%) were compared. Those with a higher index tended to have a worse prognosis, but when PCNA grade was considered, it was found to have definite independent prognostic value, tumours of low grade surviving better than those of high grade. The ability of semiquantitative PCNA grading to allow for intra-tumoural variation suggests it may have advantages over absolute counting, which is prone to sampling error when tumour heterogeneity is a major factor. The prognostic value of PC10 staining in gastric carcinoma is therefore promising.

Adult↗

PubMed1997

Semiautomatic quantitation of macrophages in human renal biopsy specimens in proteinuric states.

AIMS: To develop and validate a rapid and economical semiautomated approach to the measurement of immunostainable tissue components which is applicable to routine diagnostic practice. To apply this approach to the measurement of macrophages in renal biopsy specimens in nephrotic states, as protein in the renal tubules may induce macrophage infiltration, and the morphology of macrophages in tissue sections does not lend itself to cell counting. METHODS: Macrophages were identified by immunostaining with a pan-macrophage marker, followed by digital image capture and analysis using a macro procedure written for the freeware image analysis program NIH-Image. RESULTS: The method was rapid, robust and accurate to within the limits imposed by sampling error inherent in the use of small needle biopsy specimens. Very few macrophages are found in normal kidney (mean volume fraction (+/- 95% confidence limits) 0.04% (0.02%)) but infiltration of macrophages was detected in minimal change nephropathy (0.29% (0.12%)) and in membranous glomerulonephritis (0.42% (0.11%)). A statistically significant correlation was found between macrophage volume fraction and weight of proteinuria in minimal change nephropathy but not in membranous glomerulonephritis. Correlations were found in both diseases between macrophage volume fraction and serum creatinine at time of biopsy. CONCLUSIONS: The equipment is inexpensive and measurement takes less than one minute per biopsy specimen. The results indicate that macrophage infiltration is part of the pathological process in minimal change nephropathy and membranous glomerulonephritis. The correlation with creatinine at time of biopsy suggests that renal impairment in minimal change nephropathy may result from infiltration by immunologically active cells and not merely from haemodynamic changes in nephrons. However, the correlation is not close, indicating that the relation between macrophage infiltration and disease severity is not a simple one.

Biopsy↗

PubMed2001

The role of molecular analysis of immunoglobulin and T cell receptor gene rearrangements in the diagnosis of lymphoproliferative disorders.

AIMS: To investigate whether the analysis of immunoglobulin (Ig)/T cell receptor (TCR) rearrangements is useful in the diagnosis of lymphoproliferative disorders. METHODS: In a series of 107 consecutive cases with initial suspicion of non-Hodgkin's lymphoma (NHL), Southern blot (SB) analysis of Ig/TCR rearrangements was performed. RESULTS: In 98 of 100 histopathologically conclusive cases, Ig/TCR gene results were concordant. In one presumed diffuse large B cell lymphoma (DLCL) and one follicular lymphoma (FL) case no clonality could be detected by SB analysis, or by polymerase chain reaction (PCR) at second stage. In the DLCL, sampling error might have occurred; the FL was revised after an initial diagnosis of reactivity. In many of the histopathologically inconclusive cases Ig/TCR gene SB analysis was helpful, giving support for the histopathological suspicion. However, because of a lack of (clinical) follow up data this could not be confirmed in a few cases. CONCLUSIONS: Experienced haematopathologists or a pathologist panel can diagnose malignant versus reactive lesions in most cases without the need for Ig/TCR gene analysis and can select the 5-10% of cases that might benefit from molecular clonality studies.

Blotting, Southern↗

PubMed1981

Hereditary multiple exostoses: report of a kindred.

In a large family with 37 members with multiple exostoses, only one person has developed sarcomatous degeneration of a lesion. Our review of published reports revealed great variation in the incidence of malignancy in multiple exostoses (10 to 25%). Most studies had sampling errors leading to the apparent overstatement of risk. In large pedigrees with essentially complete ascertainment of affected subjects, the risk of malignancy is nearer 3% or less. This lower risk for malignancy may be more appropriate in counselling affected subjects.

Adolescent↗

PubMed1986

Duchenne muscular dystrophy in one of monozygotic twin girls.

Monozygotic twin girls are reported, one of whom has the typical clinical features of Duchenne muscular dystrophy despite a normal female karyotype. Although certain features of the biopsy were atypical, the clinical diagnosis was supported by persistent markedly raised blood creatine kinase levels and findings typical of DMD on electromyography and magnetic resonance spectroscopy. Analysis of an X linked DNA polymorphism in 16 independent somatic cell hybrids made between cells derived from each girl and a mouse line suggest that in one twin only the maternal X chromosome is active, whereas in the other the active X was paternally derived. More data are needed to exclude sampling error. These preliminary experimental results support the hypothesis that both girls are heterozygous for Duchenne muscular dystrophy. X inactivation, by chance, resulted in two contrasting cell masses with different active X chromosomes. This segregation was followed by, and may even have resulted in, twinning into a female pair, one normal and one with the full clinical features of the disease.

Biopsy↗

PubMed1989

The odds ratio: a useful tool in neurosciences.

The odds ratio is very useful; when used as a measure of association (or to describe the results of a randomised controlled treatment trial) it expresses both the strength and direction of the association (or size and direction of treatment effect). Its 95% confidence interval estimates the likely degree of sampling error and provides a test of significance at the 5% level. Authors, when reporting the results of descriptive studies, case-control studies and randomised controlled trials, should consider presenting their results this way rather than by simple significance testing with a chi squared test.

Cerebrovascular Disorders↗

PubMed1998

Absence of characteristic features in two patients with inclusion body myositis.

According to recently published criteria a diagnosis of definite sporadic inclusion body myositis is made if the typical histopathological abnormalities (rimmed vacuoles and abnormal accumulations of proteins, in addition to mononuclear cell infiltrates) are present. The two women described here presented with myositis which was unresponsive to treatment. Patient 1 had features of non-progressive sporadic inclusion body myositis clinically, whereas patient 2 had a very slowly progressive limb girdle syndrome. The cryostat sections of the first biopsies did not show rimmed vacuoles, even in retrospect. Only a repeated biopsy, 12 years after presentation in one patient and 18 years after presentation in the other, disclosed the typical features of sporadic inclusion body myositis. The initial absence of abnormal fibres probably represents a real absence or scarcity rather then a sampling error due to a multifocal nature of the histological abnormalities. It is of importance for the clinician to realise that some patients with myositis unresponsive to treatment, even if both clinical and histological features do not suggest sporadic inclusion body myositis, may prove to have the disease on repeated histopathological examination.

Adult↗

PubMed1995

Fallibility of transthoracic needle biopsy of anterior mediastinal masses.

Percutaneous transthoracic core needle biopsy has been advocated as a highly accurate technique for the diagnosis of anterior mediastinal masses. A patient is described with a large anterior mediastinal mass in whom the diagnosis of mediastinal carcinoid tumour was made by transthoracic core needle biopsy. At definitive surgical resection the tumour proved to be a B cell lymphoma. This case illustrates one of the important limitations of needle biopsy with its potential for sampling error.

Adult↗

PubMed2006

Identifying sites under positive selection with uncertain parameter estimates.

Codon-based substitution models are routinely used to measure selective pressures acting on protein-coding genes. To this effect, the nonsynonymous to synonymous rate ratio (dN/dS = omega) is estimated. The proportion of amino-acid sites potentially under positive selection, as indicated by omega > 1, is inferred by fitting a probability distribution where some sites are permitted to have omega > 1. These sites are then inferred by means of an empirical Bayes or by a Bayes empirical Bayes approach that, respectively, ignores or accounts for sampling errors in maximum-likelihood estimates of the distribution used to infer the proportion of sites with omega > 1. Here, we extend a previous full-Bayes approach to include models with high power and low false-positive rates when inferring sites under positive selection. We propose some heuristics to alleviate the computational burden, and show that (i) full Bayes can be superior to empirical Bayes when analyzing a small data set or small simulated data, (ii) full Bayes has only a small advantage over Bayes empirical Bayes with our small test data, and (iii) Bayesian methods appear relatively insensitive to mild misspecifications of the random process generating adaptive evolution in our simulations, but in practice can prove extremely sensitive to model specification. We suggest that the codon model used to detect amino acids under selection should be carefully selected, for instance using Akaike information criterion (AIC).

Amino Acids↗

PubMed1975

Radioimmunoassay studies of intestinal calcium-binding protein in the pig. I. Identification of intestinal calcium-binding protein in blood and response to a low calcium diet.

We have developed a radioimmunoassay for porcine intestinal calcium-binding protein (CaBP) and have used it to detect CaBP in pig plasma. Plasma CaBP is identical to intestinal CaBP on the basis of immunological activity, molecular size, and molecular charge properties. The plasma CaBP concentration was greater in the portal blood than in mixed venous blood, suggesting that blood CaBP originates in the gut. Two of four 15-week-old littermate pigs were placed on a low calcium diet (0.15% calcium, 0.65% phosphorus) and two on a control diet (0.65% calcium, 0.65% phosphorus). After 2 weeks, the entire small intestine was removed and divided into nine 1.8-m segments. CaBP was assayed in both plasma and intestinal mucosa. When the two pigs on a low calcium diet were compared with two control pigs, there was a general increase in immunoreactive CaBP in both plasma and intestinal mucosa. However, there was no increment in immunoreactive CaBP in the first 1.8-m segment of small intestine. Seventy-one percent of the increment in CaBP occurred distal to the first two segments. The largest fractional low calcium diet effect occurred in the ileum. The mean CaBP concentration for the total small intestine increased by a factor of 1.9. The plasma CaBP concentration increased by a factor of 2.6. In these pigs, plasma CaBP was a more reliable indicator of change in CaBP status than was the measurement in the proximal gut segment which contained the duodenum. The assay of CaBP in blood is convenient and may obviate the sampling errors inherent in intestinal biopsy.

Animals↗

PubMedDate not supplied

Non-squamous cell neoplasms of the larynx: radiologic-pathologic correlation.

A variety of benign and malignant non-squamous cell neoplasms may affect the larynx. Most of these uncommon laryngeal neoplasms are located beneath an intact mucosa, making diagnosis difficult with endoscopy alone, and sampling errors may occur if only traditional superficial biopsies are performed. In some laryngeal neoplasms, radiologic evaluation allows the correct diagnosis. Hemangiomas have very high signal intensity at T2-weighted magnetic resonance (MR) imaging and strong enhancement at both computed tomography (CT) and MR imaging after administration of contrast material. Phleboliths, which are pathognomonic for hemangiomas, are easily identified at CT. Chondrogenic tumors typically manifest with coarse or stippled calcifications at CT. Because of their high water content, chondrogenic tumors have very high signal intensity on T2-weighted MR images, whereas only moderate enhancement is observed after administration of contrast material. Lipomas typically manifest at both CT and MR imaging as homogeneous nonenhancing lesions. They are isoattenuating to subcutaneous fat at CT and isointense relative to subcutaneous fat with all MR pulse sequences. Metastases from renal adenocarcinoma typically demonstrate strong contrast enhancement and flow voids at MR imaging, and metastases from melanotic melanoma usually have high signal intensity on T1-weighted MR images and low signal intensity on T2-weighted images owing to the paramagnetic properties of melanin. Although radiologic findings are nonspecific in most other non-squamous cell neoplasms of the larynx (eg, Kaposi sarcoma, hematopoietic tumors, tumors of the minor salivary glands, metastases from amelanotic melanoma), cross-sectional imaging can play an important role in the diagnostic work-up of these unusual tumors by delineating the extent of submucosal tumor spread and directing the endoscopist to the appropriate site for the deep, transmucosal biopsies needed to establish the diagnosis. In addition, CT and MR imaging are crucial for posttherapeutic monitoring and early detection of local recurrence.

Carcinoma, Squamous Cell↗

PubMed1990

Gliomas: classification with MR imaging.

The findings at magnetic resonance (MR) imaging in a group of 36 pathologically verified supratentorial gliomas were analyzed and compared with the biopsy diagnoses (a) to determine whether MR imaging could be used to classify astrocytic-series tumors into a three-tiered system of low-grade astrocytoma, anaplastic astrocytoma, and glioblastoma multiforme; and (b) to evaluate MR imaging features that may aid in this classification. The MR characteristics evaluated were crossing of the midline, edema, tumor signal heterogeneity, hemorrhage, border definition, cyst formation or necrosis, and mass effect. The statistically significant MR characteristics (positive predictors) were mass effect (P = .0000) and cyst formation or necrosis (P = .0512). The MR accuracy rate approached that of neuropathologic diagnosis, which is subject to sampling errors. MR imaging may serve as an adjunct in case management when the clinical course and MR findings appear to be at odds with the neuropathologic diagnosis.

Anaplasia↗

PubMed1975

An inexpensive Plexiglas metabolism cage for the squirrel monkey (Saimiri sciureus).

A light, sturdy, and inexpensive metabolism cage for use with the squirrel monkey (saimiri sciureus) is described. The design allows for efficient urine and feces separation, ease of maintenance, and little interference with individual and social behavior patterns. Standard laboratory procedures for reduction of sampling error are presented, as well as results of a pilot study using the described apparatus. The design of the cage is such that, with minor modifications, it can be utilized by other small primates.

Animals↗