A correlative SEM/TEM examination of the endothelium surface in neural capillaries.

The modifications of the endothelial surfaces were analyzed in growing neural microvessels by scanning and transmission electron microscopes in the optic tecta of chick embryos and chickens. The endothelial inner aspect appears regular and smooth in the early stages of the vessel growth (7th incubation day). Later (14th incubation day) both the abluminal and luminal surfaces of the endothelium follow a very sinuous course and the luminal ones appear extremely rich in pleomorphic microprojections. When the endothelium differentiation is concluded (5-day-old chicken), the cells are very thin and again exhibit regular and smooth surfaces. These findings reveal a great mobility of the cell membrane of the endothelial cells when they are growing longer and thinner by a moulding process. Moreover, the presence of a number of pinocytotic pits in the embryo vessels would indicate that the neutral vessels, provided with a typically low pinocytotic activity in the adult life, are engaged in this function during development.     

Ciliated Cells in the Main Excretory Duct of the Submandibular Gland in Obstructive Sialadenitis: A SEM and TEM Study

The epithelium of the main excretory duct of the submandibular gland in five cases of obstructive sialadenitis was studied by TEM and SEM. In three cases we found a considerable increase in goblet and ciliated cells. As well as normal cilia, different kinds of ciliary anomalies, especially compound cilia, were noticed. Images of centriole formation and of ciliogenesis, both normal and abnormal, were also observed. Several hypotheses concerning the mode of formation of the compound cilia are discussed.     

A combined SEM and TEM study on the basal labyrinth of the collecting duct in the rat kidney

The three-dimensional ultrastructure of principal cells in the rat renal collecting duct was studied by scanning electron microscopy (SEM) using the NaOH digestion technique and the aldehyde prefixosmium-DMSO-osmium method, as well as by transmission electron microscopy (TEM). Special reference was given to the basal labyrinth of the cells and its numerous ruffles and infoldings of the basal plasma membrane. Observations showed that, as the collecting duct descends from the cortical collecting duct (CCD) to the terminal portion of the inner medullary collecting duct (t-IMCD), the pattern of the labyrinth gradually simplified and the ruffles grew thinner. In the CCD, the labyrinth was conspicuously complicated in structure, being formed of tightly arranged ruffles of uniform shape and thickness (70 nm). From the outer medullary collecting duct (OMCD) to the initial portion of inner medullary collecting duct (i-IMCD), the labyrinth became less complicated due to the mingling of wide flattened ruffles. Also, the basal infoldings were reduced in depth (from 700 nm in CCD to 500-600 nm in i-IMCD). In the t-IMCD, the labyrinth was rudimental, and instead presented small grooves (300 nm in depth) which corresponded to indentions of the basal plasma membrane. The regional simplification of the labyrinth was accompanied by morphological changes in mitochondria suggesting their functional decline: the electron density and number of cristae were reduced, these being changed in shape from plate-like to vesicular. These morphological data readily account for the potential for active transport by the collecting duct, which is highest in the CCD and is decreased towards the t-IMCD, and which may function merely as an excretory duct of urine from the papilla. The present study three-dimensionally demonstrates fine-structural heterogeneity in different segments of the collecting duct of the rat kidney.     

Changes in the endothelial morphology of the developing semilunar heart valves. A TEM and SEM study in the chick

In view of recent evidence showing that shape and orientation of endothelial cells is determined by blood flow, the endothelium of the semilunar valves was studied in the developing chick heart using transmission and scanning electron microscopy. The results reveal significant developmental modifications of endothelial morphology and structure. These modifications can be linked to modifications of local blood flow and can also explain several aspects of valvular morphogenesis. The results substantially support the hypothesis of an involvement of hemodynamics in the development of the semilunar valves.     

The amniotic, allantoic and yolk sac epithelia of the cat: SEM and TEM studies

Summary The epithelial layers of the feline allantoamnion and yolk sac between the 23rd day and full term were studied using SEM, TEM, and light microscopical histochemistry. Amniotic, allantoic and yolk sac fluid were analysed. The attenuated and relatively inert amniotic epithelium sloughs off completely around the 54th day, the amniotic cavity is then lined by fibrous connective tissue only. The exocoelomic epithelium is regarded as the source of the abundant macrophages, rich in lysosomal enzymes, that are seen in the allantoamniotic membrane after obliteration of the exocoelomic cleft. The allantoic epithelium has been mistaken for the amniotic one by many authors. Its cuboidal, glycogen-rich cells develop coral-like luminal outgrowths after the 45th day, which contain almost all kinds of organelles. The basal cell poles form large interdigitations, and the nuclei become heavily lobulated. The changes are accompanied by drastic alterations in the ionic composition of the allantoic fluid. The yolk sac endoderm differs greatly from the allantoic endoderm. It is the most active epithelium of the accessory fetal membranes. The yolk sac mesothelium retains many long microvilli over the whole gestational period. The nutritional value of the yolk sac fluid is only higher than that of the amniotic fluid in its glycerol and cholesterol values.     

Studies on the actions of glutaraldehyde, formaldehyde, and mixtures of glutaraldehyde and formaldehyde on tissue proteins

The effects of aldehyde fixation on tissue proteins was studied using SDS-polyacrylamide gel electrophoresis. Fixation with low concentrations of formaldehyde or glutaraldehyde had only a slight effect on the protein banding pattern. On the other hand, most of the original protein bands were absent after a short treatment with mixtures of formaldehyde and glutaraldehyde. Spectral absorption measurements showed a stronger absorption at both gamma = 280 nm and gamma = 235 nm with the glutaraldehyde-formaldehyde mixture than with glutaraldehyde alone.     

A comparison of normalization effects on three whole-body cylindrical 3D PET systems

Normalization coefficients in three-dimensional positron emission tomography (3D PET) are affected by parameters such as camera geometry and the design and arrangement of the block detectors. In this work, normalization components for three whole-body 3D-capable tomographs (the GE Advance, the Siemens/CTI962/HR+ and the Siemens/CTI951R) are compared by means of a series of scans using uniform cylindrical and rotating line sources. Where applicable, the manufacturers' normalization methods are validated, and it is shown that these methods can be improved upon by using previously published normalization protocols. Those architectural differences between the three tomographs that affect normalization are discussed with a view to drawing more general conclusions about the effect of machine architecture on normalization. The data presented suggest that uniformity of system response becomes easier to achieve as the uniformity of crystal response within the detector block is improved.     

A study of the effects of glutaraldehyde and formaldehyde on the mechanical behaviour of bovine pericardium

The inherent variability in the mechanical behavior of bovine pericardium causes difficulties in establishing the effects of treatment procedures used in the manufacture of bioprosthetic cardiac valves. A new experimental technique has been developed in which the specimen acts as its own control, obviating the need to perform large numbers of experiments to obtain statistically significant results. The procedure used is described in detail as is the equipment employed. The technique was used to assess the effect of glutaraldehyde and formaldehyde on the stress/strain response of bovine pericardium. The results show that the fixing process in glutaraldehyde is virtually complete within two hours and causes significant changes in the mechanical behaviour of the tissue. The tissue becomes progressively stiffer as the treatment period is extended, which is especially pronounced at low levels of stress. Formaldehyde storage subsequent to fixing in glutaraldehyde was found to have no effect on the stress/strain response of the bovine pericardium.     

A comparison of the central effects of different progestins used in hormone replacement therapy

Objective: To evaluate the central effect exerted by different progestins used for hormone replacement therapy. Methods: Randomised, placebo-controlled study. One hundred-twenty postmenopausal women on continuous hormonal replacement therapy with transdermal estradiol (50 μg per day) associated, for 10 days every 28 days, with four different progestins: dydrogesterone (DYD; 10 mg per day; n=20), medroxyprogesterone acetete (MPA; 10 mg per day; n=20), nomegestrol acetate (NMG; 5 mg per day; n=20) or norethisterone acetate (NETA; 10 mg per day; n=20). Other 40 women, 10 for each treatment group, were used as controls and were monitored for a single cycle of 28 days during the administration of transdermal estradiol plus placebo. Morning basal body temperature (BBT) was monitored for 28 days. Anxiety, by the state-trait anxiety inventory, and depression, by the self-evaluation depression scale of Zung, were evaluated just prior to and in the last 2 days of the 10-day progestins adjunct. Results: All progestins except DYD increased (P<0.0001) BBT by 0.3–0.5 °C. Anxiety was decreased by DYD (−2.3+1.1; P<0.01) and MPA (−1.5+0.5; P<0.01), but not by NMG or NETA. Depression did not significantly increase during progestins and actually decreased during MPA (−3.0+0.7; P<0.01). Only the effect of DYD on anxiety and that of MPA on depression were significant versus the control group (P<0.05). Conclusions: Different progestins exert different central effects. DYD has the peculiarity of not increasing BBT and of decreasing anxiety, which is also decreased by MPA. Depression is not negatively affected by the tested progestins and it may be ameliorated by MPA. The present data may help to individualise the progestin choice of hormone replacement therapy.     

Intramembranous particle distribution in human erythrocytes: effects of lysis, glutaraldehyde, and poly-L-lysine.

Freeze-fracture combined with quantitative electron microscopy of the intact human erythrocyte (RBC) and ghost revealed significant differences in their intramembranous particle coefficients. External (E) fracture-faces of unfixed ghost membranes were found to contain 40% fewer particles than those of intact unfixed RBC. The particle distribution of the intact RBC membrane depended on the use of glutaraldehyde fixation and glycerol cryoprotection. Whereas glutaraldehyde- and glycerol-treated cells disclosed 70% fewer E-face particles than did intact unfixed cells, poly-L-lysine-treated, intact, unfixed RBC showed no such differences. Treatment with a combination of poly-L-lysine and glutaraldehyde, however, increased the amount of E-face particles while reducing those of the protoplasmic (P) face. The poly-L-lysine effect varied with its concentration and was unaffected by previous application of neuraminidase. Nor did the lectin phytohemagglutinin induce particle rearrangement in intact cells. Our data demonstrate that the processes of glutaraldehyde fixation and glycerol cryoprotection modify the RBC membrane by decreasing the number of E-face particles present. In addition, the combination of poly-L-lysine and glutaraldehyde alters the affinity of some particles for one half of the membrane, suggesting that in freeze-fractured RBC, chemical bonds formed at the extracellular surface of the membrane can influence particle partitioning.     

A comparison of three neuropsychological tests: the Weigl, Hooper, and Benton

The accuracy of prediction of brain dysfunction for three neuropsychological tests-the Weigl, the Hooper, and the Benton-was compared. Sixty-six male, veteran, psychiatric inpatients were administered all three tests, and diagnoses of brain dysfunction or intactness were made by their ward psychiatrist, who used neurodiagnostic techniques. The results disclosed that each test alone can predict brain dysfunction significantly better than chance. All chi 2 tests were significant at the .025 level or better. When the Weigl was used as a moderator variable with the Hooper and also with the Benton, the p values for each test were somewhat reduced (p = .005 and .01), an indication of improvement in predictive power. When the percentage of predictive accuracy (hit rates) for the three tests used alone and in combination was analyzed, it was shown that the hit rate is increased by combining the Weigl with the Hooper and also with the Benton. It is increased further by combining all three tests into a predictive index.     

A comparison of the effects of lipoproteins of two progestogens used during cyclical hormone replacement therapy

Lipoprotein levels were measured in 11 women who had been treated with 0.625 mg/day conjugated equine oestrogens with the addition of 0.15 mg/day DL-norgestrel for the last 12 days of each 28 day cycle for 48 wk. Treatment was then changed to an identical oestrogen regimen with dydrogesterone, 10 mg/day, as progestogen and monitoring continued for a further 24 wk. The oestrogen plus norgestrel regimen caused a significant reduction in low density lipoprotein (LDL) cholesterol levels. During the 24 wk after the change of therapy, levels of high density lipoprotein (HDL) increased significantly due to an increase in the HDL2 fraction and there was an upward trend in LDL cholesterol which did not attain statistical significance. We conclude that, when used in combination with conjugated equine oestrogens, changing from norgestrel, 0.15 mg/day, to dydrogesterone, 10 mg/day, does not lead to any significant improvement in lipoprotein profile.     

Human adenohypophyseal quantitative histochemical cell classification. II. Evaluation of the effects of two fixatives and postmortem intervals.

Quantitative cell counts on specific pituitary areas were done on differentially stained adenohypophyseal sections obtained at autopsy (four to 22 hours postmortem). We used specific criteria formulated from studies by previous authors to identify functional classes of secretory cells. We compared the effects of two fixatives, calcium acetate-buffered formaldehyde solution (CAF) and formol sublimate (FS), on morphologic identification. Calcium acetate-buffered formaldehyde solution is superior in identifying gonadotrophs and prolactin cells morphologically. Formol sublimate is superior in identifying the other cell types morphologically. Approximately 10% to 15% more cells could be classified by fixing with FS rather than CAF. The effect of postmortem autolysis was minimal. The only statistically significant (P less than .025) effect was the presence of a higher percentage of disrupted unclassifiable cells in CAF-fixed basophil areas at 12 to 24 hours than was present at 0 to 12 hours.     

Glial fibrillary acidic protein expression in pleomorphic adenoma, chordoma, and astrocytoma. A comparison of three antibodies.

Glial fibrillary acidic protein (GFAP) is a major constituent of glial cytoplasmic intermediate filaments. Glial fibrillary acidic protein expression has been accepted as a marker of astroglial differentiation or origin. However, GFAP expression has been demonstrated in a variety of normal and neoplastic tissues outside the central nervous system, including pleomorphic adenomas, chordomas, bone, and cartilage. It has been postulated that coexpression of GFAP and vimentin in neoplastic myoepithelial cells in pleomorphic adenomas reflects early chondroid differentiation. Glial fibrillary acidic protein expression in chondromyxoid and chordoid tumors was studied in formaldehyde solution-fixed, paraffin-embedded sections of 20 pleomorphic adenomas and 10 chordomas by the immunoperoxidase method with the use of commercially available monoclonal (n = 2) and polyclonal (n = 1) antibodies. All pleomorphic adenomas and chordomas demonstrated expression of GFAP with the use of the polyclonal antibody (Biomeda Corp [Foster City, Calif]). Variable expression of GFAP was present in 90% (18/20) and 70% (14/20) of pleomorphic adenomas, and in 20% (2/10) and 0% of chordomas, with the use of the two monoclonal preparations (Dakopatts [Glostrup, Denmark] and BioGenex Laboratories [San Ramon, Calif]), respectively. Normal brain tissue and eight astrocytomas were used as "controls" to compare staining intensity and quality between the polyclonal and monoclonal anti-GFAP antibodies. Glial fibrillary acidic protein positivity with the polyclonal antibody was more intense than that with either monoclonal antibody despite similar (congruent) distributions of tumor cell types that were stained in control brain and astrocytoma tissues. The GFAP polyclonal antibody was more frequently immunoreactive than the monoclonal antibodies, particularly in cells that exhibited chondroid differentiation. These findings may have practical application in surgical pathology.     

Detecting change: A comparison of three neuropsychological methods, using normal and clinical samples.

Detecting change in individual patients is an important goal of neuropsychological testing. However, limited information is available about test-retest changes, and well-validated prediction methods are lacking. Using a large nonclinical subject group (N = 384), we recently investigated test-retest reliabilities and practice effects on the Wechsler Adult Intelligence Scale and Halstead-Reitan Battery. Data from this group also were used to develop models for predicting follow-up test scores and establish confidence intervals around them. In this article we review those findings, examine their generalizability to new nonclinical and clinical groups, and explore the sensitivity of the prediction models to real change. Despite similarities across samples in reliability coefficients and practice effects, limits to the generalizability of prediction methods were found. Also, when multiple test measures were considered together, one or more "significant" changes were common in all (including stable) subject groups. By employing normative cut-offs that correct for this, sensitivity of the models to neurological recovery and deterioration was modest to good. More complex regression models were not more accurate than the simpler Reliable Change Index with correction for practice effects when confidence intervals for all methods were adjusted for variations in level of baseline test performance.