Comparison between histopathology and DNA histogram of testis

From January to July 1989, the DNA histogram of testicular open biopsies was done for 11 patients of primary infertility and 7 patients of a control group. There were 2 failures in these 36 specimens. The flow cytometric analysis revealed characteristic patterns in the relative numbers of haploid (1C), diploid (2C), and tetraploid (4C) cells. In the presence of normal spermatogenesis, the haploid compartment contained the majority of cells, followed by the diploid, and then the tetraploid (1C greater than 2C greater than 4C). The other diagnostic criteria of flow cytometry were as follows: hypospermatogenesis (2C greater than 1C greater than 4C), the maturation arrest (2C greater than 4C greater than 1C), and Sertoli-cell-only syndrome (2C, near 100%). According to the aforementioned diagnostic criteria, the results of DNA histograms were compared with the histopathology diagnosed by junior or senior pathologists. These patterns of DNA histograms correlated with the diagnoses by senior pathologists in 28 of 34 specimens (82.6%), while there were only 20 of 36 pathologic diagnoses (55.6%) which matched between junior and senior pathologists. It is shown that abundant experience is needed for testis pathologists to diagnose accurately. The DNA histograms correlate well with pathological findings, with the advantages of quantification and fewer specimens needed. In conclusion, testicular tubular cell DNA histograms appear to be a reliable modality in the evaluation of spermatogenesis. They provide the quantitative information of sperm maturation and help in making appropriate decisions in the management of male infertility.     

Efficacy of combined image and flow cytometric DNA assessments in human breast cancer: a methodological study based on a routine histopathological material of 2024 excised tumour specimens

In 2024 excised specimens of malignant tumours of the female mammary gland. the nuclear DNA distribution pattern of the neoplastic cells was assessed by means of two procedures. One was image cytometry (ICM); here, all the 2024 samples were assessed. The other was flow cytometry (FCM) where 1336 specimens were analysed. In 829 of the 2024 tumour nodules the results of ICM and FCM could be compared. The efficacy of both techniques alone was about 80%; that of the combination was about 60%. In the ICM procedure the main reason for the reduction of samples was the failure to obtain representative specimens. The losses in the FCM method were due to poor quality of the histograms (too much background noise and too broad coefficients of variation). In addition, in as much as one third of all the cases, no specimens were set aside for FCM assessments. In 16% of the samples, where the results of the ICM assessment could be compared with those of the FCM analyses, completely diverging DNA ploidy patterns were obtained. The discrepancy was caused by differences in the interpretation of the histograms. In addition, the calculations of so-called S-phase fractions from the diploid FCM histograms was found to be associated with methodological errors, further contributing to differences in the DNA assessments by means of ICM and FCM. Nevertheless, it was advantageous to use combined ICM and FCM assessments, particularly in the interpretation of DNA histograms of uncommon types.     

Effect of surrounding tissue on vessel fluid and solid mechanics

There is no doubt that atherosclerosis is one of the most important health problems in the Western Societies. It is well accepted that atherosclerosis is associated with abnormal stress and strain conditions. A compelling observation is that the epicardial arteries develop atherosclerosis while the intramural arteries do not. Atherosclerotic changes involving the epicardial portion of the coronary artery stop where the artery penetrates the myocardium. The objective of the present study is to understand the fluid and solid mechanical differences between the two types of vessels. A finite element analysis was employed to investigate the effect of external tissue contraction on the characteristics of pulsatile blood flow and the vessel wall stress distribution. The sequential coupling of fluid-solid interaction (FSI) revealed that the changes of flow velocity and wall shear stress, in response to cyclical external loading, appear less important than the circumferential stress and strain reduction in the vessel wall under the proposed boundary conditions. These results have important implications since high stresses and strains can induce growth, remodeling, and atherosclerosis; and hence we speculate that a reduction of stress and strain may be atheroprotective. The importance of FSI in deformable vessels with pulsatile flow is discussed and the fluid and solid mechanics differences between epicardial and intramural vessels are highlighted.     

Deviation from a Poisson distribution in a series of identical tests of E. coli cultures as a result of the effect of correlating factors of exo- and endogenous natures]

Vital cells number (VCN) in the sampling of E. coli populations was experimentally measured and distribution histograms were obtained. In most cases distributions show considerable deviation from Poisson model. VCN distribution histograms are polymodal, dispersion/arithmetical mean ratio may essentially differ from 1. The more essential differences from Poisson distribution were observed for populations with the higher cell concentration. Computer simulation of the VCN histograms indicated that additional parameters (such as those describing cellular interaction of different nature and/or other factors that influence random behaviour of cells) should be introduced into Poisson model to explain observed variations in VCN distribution histograms.     

DNA flow cytometric analysis of mouse seminiferous epithelium

In order to provide a basis for quantitative studies of murine spermatogenesis, we performed a DNA flow cytometric analysis on the mouse seminiferous tubules isolated at defined stages of the epithelial cycle by transillumination-assisted microdissection. Accurate stage identification was performed by examining spermatids in the adjacent tubule segments by phase-contrast microscopy. For flow cytometry, suspension of nuclei of spermatogenic cells was obtained by detergent treatment of isolated seminiferous tubules, and fresh samples were stained with propidium iodide. DNA histograms of the 12 stages of the mouse seminiferous epithelial cycle varied in a stage-specific manner. DNA histograms of stages I-VIII of the cycle were characterized by a hypofluorescent haploid peak, the location of which changed with the decreasing DNA dye (propidium iodide)-binding capacity of elongated spermatids. The absence of the hypohaploid peak and the high ratio of the cells with 4C amount of DNA to the cells with 1C amount of DNA characterized stages IX-XI of the cycle. Stage XII showed a high 2C peak, owing to a large population of secondary spermatocytes arisen from the first meiotic division. By using fluorescent beads as an internal volume standard cell numbers in defined stages were determined. These data provide a basis for quantitative studies of mouse spermatogenesis.     

“Cytogenetic” studies of spermatids of mice carrying Cattanach's translocation by flow cytometry

The DNA content of spermatids of mice carrying Cattanach's translocation has been measured with high precision by flow cytometry. The observation that the two peaks of DNA content in the haploid region of the DNA histograms represent X-and Y-bearing spermatids was tested and confirmed. Using flow cytometry, the difference in DNA content between the X and Y chromosomes in these mice was measured to be 5.2±0.1% of the total haploid genome as compared to 3.4±0.1% in normal mice. These results demonstrated the precision of flow cytometry for cytogenetic studies. Additional information on spermatogenesis in mice bearing Cattanach's translocation was obtained and showed a gradual loss of cells during spermatogenesis in those bearing the balanced form of the translocation.     

Cell-cycle, protein content, and nuclear size in acute myeloid leukemia

Simultaneous analysis of DNA and cellular proteins provides information on cell proliferation and metabolism. Cellular protein content coupled with nuclear geometric parameters can be used to evaluate cellular maturation and differentiation. In this study, leucoblasts from 50 cases of adult acute myeloid leukemia were analyzed by flow cytometry, and semiautomatic morphometry was performed on bone marrow smears. Ethanol-fixed bone marrow blast cells were stained for DNA with propidium iodide (PI) and for proteins with fluorescein isothiocyanate (FITC). On the resulting FITC versus PI histograms we defined the cells with low protein content which are associated with a nonproliferating subpopulation (LPC fraction). Low protein content fraction and S-phase are correlated (p less than 0.01). The LPC fraction values are more dispersed than S-phase values and thus should indicate more clearly eventual differences between cellular populations. This hypothesis has been tested with the prognostic significance of cell-cycle variables: The LPC fraction was significantly higher in the complete remission group than in the other (p less than 0.01), while S-phase did not show any difference. The peak value of the protein content histograms is significantly lower in the granulocytic leukemias (M1, M2, M3) than in the leukemias with a monoblastic component (M4, M5). Furthermore, we showed that the differentiation and the maturation of the myeloid blast cells modify the nuclear size. The combination of these two parameters provides useful information for cytological classification.     

A practical graphical method for estimating the fraction of cells in S in DNA histograms from clinical tumor samples containing aneuploid cell populations

A graphical method for the analysis of unperturbed DNA histograms is presented in which the area of the normalized histogram subtended by the fraction of cells in S is represented by a trapezoid whose dimensions are dependent on features common to all such histograms. The technique takes measurement variability into account. This method was applied to a variety of synthetic DNA histograms. Overall, calculated values for the fraction of cells in S correlated well with actual values. This method was applied to 36 diploid cases of non-Hodgkin lymphoma; results correlated well with those obtained by a computer-based method. The results of the graphical-method were also highly reproducible between different observers. The graphical method can be used in the presence of aneuploid cell populations. Techniques for calculating S fractions in the presence of aneuploidy in clinical samples are described. These techniques were applied to synthetic histograms of mixed diploid and aneuploid populations. Calculated values correlated well with actual values.     

Gene expression profiles of mouse spermatogenesis during recovery from irradiation

Background  

Irradiation or chemotherapy that suspend normal spermatogenesis is commonly used to treat various cancers. Fortunately, spermatogenesis in many cases can be restored after such treatments but knowledge is limited about the re-initiation process. Earlier studies have described the cellular changes that happen during recovery from irradiation by means of histology. We have earlier generated gene expression profiles during induction of spermatogenesis in mouse postnatal developing testes and found a correlation between profiles and the expressing cell types. The aim of the present work was to utilize the link between expression profile and cell types to follow the cellular changes that occur during post-irradiation recovery of spermatogenesis in order to describe recovery by means of gene expression.     

Pathology of skeletal muscle in mitochondrial disorders

Muscle histology is an essential component of the diagnostic work-up for mitochondrial cytopathies and is very important in both ruling in disease as well as ruling out the disease (i.e., alternate diagnoses). A muscle biopsy method must provide tissue for histology, electron microscopy, enzymes and DNA and this can be obtained with a suction-modified 5 mm needle. Proper embedding and processing is important for optimal diagnostic yield. The essential stains for mitochondrial histology remain the modified Gomori trichrome, cytochrome oxidase, succinate dehydrogenase, and NADH. Electron microscopy can be helpful in selected cases, however, the decision to perform this on all samples remains a contentious issue. Some cases of mitochondrial cytopathy may show no abnormalities on histology or electron microscopy (i.e., LHON), whereas, other conditions can mimic mitochondrial disease through secondary mitochondrial changes (i.e., inclusion body myositis). Athletes show evidence of increased mitochondrial numbers but do not normally develop ragged red fibers or paracrystalline inclusions. Aging is associated with an accumulation of mitochondrial abnormalities and is an important factor to consider in the interpretation of the sample. For example, biopsies in young children with mitochondrial disease may be normal at the histological level and otherwise healthy older adults can show mitochondrial changes such as ragged red and COX-negative fibers.     

Rapid hypotonic method for flow cytofluorometry of monolayer cell cultures. Some pitfalls in staining and data analysis.

The rapid hypotonic staining procedure developed by Krishan for DNA determinations by flow cytofluorometry has been proven accurate for in vivo cell samples and for cell lines growing in suspension culture. We show that the unmodified procedure may produce distorted DNA histograms when used for staining cells growing in monolayer cultures, however. To eliminate these distortions, it was necessary to avoid the use of trypsin by staining the attached cells directly, using a hypotonic fluorochrome solution to which nonionic detergent was added. Two sublines of HeLa S3 cells are shown to exhibit major differences in their staining characteristics. By using our revised staining procedure, the two sublines appear to produce very satisfactory DNA histograms. However, in only one subline does the S phase fraction calculated from the histograms agree with the autoradiographical labeling index. Mitotic cells remain intact under these staining conditions, and the principal observed effect of nonionic detergents in this case is to decrease the coefficient of variation of fluorescence intensity.     

High glucose concentrations induce oxidative damage to mitochondrial DNA in explanted vascular smooth muscle cells

Oxidative stress is considered to be one of the mechanisms leading to atherosclerosis. It occurs in response to injury or to altered metabolic state. Alterations in cell growth (proliferation or apoptosis) can also contribute to the pathogenesis of atherosclerosis and is influenced by oxidative stress. Smooth muscle cells (SMC) from aortic explants of JCR:LA-cp homozygous cp/cp corpulent rats who are genetically predisposed to develop atherosclerosis exhibit increased SMC proliferation, which can be attenuated by exercise and food restriction. This study was conducted to characterize the effects fo oxidative stress and high glucose media on cell growth and its relationship to mitochondrial DNA integrity and gene expression in explanted aortic SMC from corpulent and lean JCR:LA-cp rats. The results show that SMC from the cp/cp rat appear to be resistant to oxidant-induced cell death and that they accumulate mitochondrial DNA mutations, probably as a result of a reduction in apoptosis. These data suggest that susceptibility to age- and glucose-related atherosclerosis may be related to alterations in redox signaling.     

The problem of cell debris in pulse-cytophotometry: A probability theoretic model

The problem of cell debris in pulse-cytophotometry is considered on the basis of a probability-theoretic model and the results are compared with the model of a pure exponential function for the portions of the DNA fragments in the channels of the flow cyclometer, which is generally used in practice. The model is based on the assumption that the possible decomposition of the DNA content of a single cell into some parts as a consequence of the necessary preparation of the cell material for measurement can be interpreted as a Poisson point process. Therefore the number of divisions of the DNA content of a cell is assumed as a Poisson random variable. It follows a well-defined distribution function of the DNA content in the common population of intact cells and fragments depending on the apriori distribution before pretreatment. This distribution determines a theoretical histogram which can be compared with the measurements. The results corroborate the assumption of a pure exponential course for the portions of DNA fragments only in the area of very small DNA contents. For greater DNA contents there are differences between the pure exponential course and the model described here depending on the a priori distribution and on the intensity of the cell disintegration process. As a byproduct, an estimation of the fraction of disintegrated cells is obtained with respect to the fraction of fragments. A corresponding computer program was applied to a number of experimental histograms. The results have shown that the theory describes the measured histograms satisfactory in most cases.     

Modified Methodology to Improve Flow Cytometric Dna Histograms from Paraffin-Embedded Material

Flow Cytometric (FCM) DNA content analysis of paraffin-embedded tissues has become a widely accepted procedure in assessing the biologic course in some tumors from archival material. Difficulty in interpreting histograms is frequently due to high levels of debris, and wide coefficients of variation (CV). These may lead to underestimating near-diploid abnormality. Although the clinical significance of low-degree aneuploidy has yet to be established, the procedure reported here improved our endeavor to detect DNA Indices (DI) of at least 1.1%. Experience has shown that careful technique can result in overall improvement of DNA histograms by lowering levels of debris and % CV, dramatically so in some cases. Archival histograms can be generated that rival in quality fresh tissue results. Archival material is currently employed for diagnostic and research purposes.     

Modified methodology to improve flow cytometric DNA histograms from paraffin-embedded material

Flow Cytometric (FCM) DNA content analysis of paraffin-embedded tissues has become a widely accepted procedure in assessing the biologic course in some tumors from archival material. Difficulty in interpreting histograms is frequently due to high levels of debris, and wide coefficients of variation (CV). These may lead to underestimating near-diploid abnormality. Although the clinical significance of low-degree aneuploidy has yet to be established, the procedure reported here improved our endeavor to detect DNA Indices (DI) of at least 1.1%. Experience has shown that careful technique can result in overall improvement of DNA histograms by lowering levels of debris and % CV, dramatically so in some cases. Archival histograms can be generated that rival in quality fresh tissue results. Archival material is currently employed for diagnostic and research purposes.     

Flow cytometric DNA content of fresh tumor specimens using keratin-antibody as second stain for two-parameter analysis.

Studies concerning flow cytometric assessed DNA content reveal problems in interpretating DNA histograms of tumor specimens. The main problems are histograms with a broad coefficient of variation in the G0/G1 fraction; a high G2M fraction and samples with a low percentage of tumor cells. Therefore, in the present study, 382 fresh tumor specimens of carcinomas were analysed routinely, double labeled with, on the one hand, propidium-iodide for assessing DNA content and, on the other, a monoclonal keratin-antibody for marking epithelial and tumor cells. Of the 311 tumor samples, using single parameter analysis 165 (54%) were classified as DNA aneuploid and 146 (46%) as DNA "euploid." By double parameter analysis, 224 (72%) samples were keratin positive and 87 (27%) keratin negative and, of the 224 keratin positive tumors, 175 (78%) were DNA aneuploid and 49 (22%) DNA euploid. The DNA histograms of single and double parameter analysis were compared and it was concluded that in 24 cases (11%) keratin labeling was necessary to recognize DNA aneuploidy. In another 23 (10%) cases, keratin labeling was helpful in assessing DNA aneuploidy. Finally when the results of the 311 samples were combined, 215 (68%) were scored as DNA aneuploid and 99 (32%) DNA euploid. Thus the overall gain in assessing DNA aneuploidy using the double labeling technique is 14%. In conclusion, it is shown that keratin labeling on fresh tumor cell suspensions of epithelial tumors is of additional value in establishing DNA content. Because single parameter DNA assessment is adequate in approximately 60% of the tested samples, the double labeling technique can be performed routinely, or after initial single parameter DNA assessment. Histograms having a broad CV and/or a high G2M are good candidates for the double labeling technique. Using this technique, DNA-content assessment becomes more reliable.     

Plasma cortisol in men--relationship with atherosclerosis of retinal arteries

The production of cortisol increases in acute stress but the effects of chronic stress on plasma cortisol are still controversial. Stress on the other hand plays a role in coronary artery disease (CAD) and carotid atherosclerosis. Since there is no data about plasma cortisol and atherosclerosis of the retinal arteries, the purpose of this study was to explore the relationship between plasma cortisol in 101 adult males with the degree of their retinal vessels atherosclerosis. The results were compared with those in 47 matched apparently healthy men with no retinal vessels changes. The atherosclerotic changes of retinal vessels were determined by direct ophthalmoscopy and graded (1-4) according to Scheie. Morning plasma cortisol levels were determined by radioimmunoassay using commercial kits. The results were compared by using chi-square test. No association between morning plasma cortisol concentrations and retinal vessels atherosclerosis could be found. The results of this study do not support a role for physiological levels of plasma cortisol in the development of atherosclerosis, at least of the retinal arteries, in men.     

Infertility in 5,10-methylenetetrahydrofolate reductase (MTHFR)-deficient male mice is partially alleviated by lifetime dietary betaine supplementation

Metabolism of folate is essential for proper cellular function. Within the folate pathway, methylenetetrahydrofolate reductase (MTHFR) reduces 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, a methyl donor for remethylation of homocysteine to methionine, the precursor of S-adenosylmethionine. S-adenosylmethionine is the methyl donor for numerous cellular reactions. In adult male mice, MTHFR levels are highest in the testis; this finding, in conjunction with recent clinical evidence, suggest an important role for MTHFR in spermatogenesis. Indeed, we show here that severe MTHFR deficiency in male mice results in abnormal spermatogenesis and infertility. Maternal oral administration of betaine, an alternative methyl donor, throughout pregnancy and nursing, resulted in improved testicular histology in Mthfr-/- offspring at Postnatal Day 6, but not at 8 mo of age. However, when betaine supplementation was maintained postweaning, testicular histology improved, and sperm numbers and fertility increased significantly. We postulate that the adverse effects of MTHFR deficiency on spermatogenesis, may, in part, be mediated by alterations in the transmethylation pathway and suggest that betaine supplementation may provide a means to bypass MTHFR deficiency and its adverse effects on spermatogenesis by maintaining normal methylation levels within male germ cells.     

Behavior of mitochondria during eupyrene and apyrene spermatogenesis in the silkworm,Bombyx mori (Lepidoptera), investigated by fluorescence in situ hybridization and electron microscopy

Summary Changes in the morphology and quantity of mitochondria and mitochondrial DNA during eupyrene and apyrene spermatogenesis in the silkworm were examined by electron microscopy and by fluorescence in situ hybridization with a 2 kb silkworm mitochondrial DNA clone (pBmMtE2). In the eupyrene spermatogenesis, the spermatocytes at early prophase I contained only a small amount of cytoplasm and showed a rather faint signal. As the cells grew larger in the later prophase I, the signal grew stronger. In the eupyrene spermatids, an especially strong signal was evident in the nebenkerns, in which all the cell's mitochondria were aggregated, and the strong fluorescence was maintained in mitochondrial derivatives. On the other hand, the apyrene cells were markedly smaller throughout spermatogenesis, showing much fainter signals for mitochondrial DNA than the eupyrene. Electron microscopy disclosed considerable differences in the behavior of mitochondria between the apýrene and the eupyrene cells. The observed qualitative and/or quantitative differences in the mitochondria may have some physiological bearing on the spermatogenesis of the two types of sperm.Abbreviations FISH fluorescence in situ hybridization - FITC fluorescein isothiocyanate - kb kilo base pair - PI propidium iodide - PBS phosphate-buffered saline