Gomori's Aldehyde Fuchsin Research Articles

Evaluating Three Elastic-Fiber Staining Methods for Detecting Visceral Pleural Invasion in Lung Adenocarcinoma Patients.

The aim of this study was to evaluate the accuracy of three combination staining approaches, each composed of pancytokeratin immunostaining with an elastic-fiber staining method of choice, in diagnosing visceral pleural invasion (VPI) in lung adenocarcinoma patients. Tissue samples were resected from 23 lung adenocarcinoma patients, for whom neither hematoxylin and eosin nor Gomori's aldehyde-fuchsin (GAF) staining accurately detected the presence of VPI. Three slices were prepared from each sample and examined by immunohistochemical staining of cytokeratin AE1/AE3 and one of the following methods for elastic-fiber staining, including Victoria blue (VB), GAF, or Weigert's resorcin-fuchsin (WRF). The staining scores and slider view time were compared among the three staining protocols with tumor extension beyond the elastic layer of the visceral pleura as the diagnostic criterion for VPI. Conclusive diagnoses were achieved for all 23 tissue samples stained with VB, 18 with GAF, and 17 with WRF. VB staining was the fastest of the three methods, and produced significantly brighter, clearer color, and better contrast between the elastic fibers and tumor cells, thus facilitating slide review. The combination of VB elastic fiber and cytokeratin AE1/AE3 staining is a user-friendly, fast, and highly effective method that produces bright stains, favorable color contrast against the background, and high tumor localization accuracy. Hence, this method can improve the accuracy of VPI diagnosis and the corresponding staging of lung adenocarcinoma. We recommend the combined use of VB and pancytokeratin immunostaining when VPI is suspected.

Histological, histochemical, and immunohistochemical studies of hippocampus in male New Zealand rabbits.

The present study aims to give detailed histomorphological features of the hippocampus of adult male New Zealand rabbits. Both histological and histochemical specimens were prepared to be examined microscopically by using a light microscope. The hippocampus appeared as C-shaped hippocampal proper, dentate gyrus, and subiculum. The hippocampal proper subdivided along its length according to the density and size of its major constituent pyramidal cells into four distinct regions named Cornu Ammonis (CA1, CA2, CA3, and CA4). With the histochemical preparations, each of these regions consisted of five layers, stratum alveolus, stratum oriens, stratum pyramidale, stratum radiatum, and stratum lacunosum-moleculare. The stratum pyramidale constituted the middle dark zone and contained the principal excitatory neurons and a few interneurons. Histochemically, the pyramidal neurons along all regions of the CA reacted positively to Grimelius silver impregnation, lead hematoxylin, Gomori's aldehyde fuchsin, aldehyde thionine, Gomori's chrome alum hematoxylin, and performic acid alcian blue stains. Immunohistochemically, the pyramidal neurons reacted positively to anti-NSE antibodies. The dentate gyrus was formed of three distinct layers. The subiculum was formed of proper subiculum, presubiculum, and parasubiculum.

Long-term Food Additive Monosodium Glutamate Induces the Differentiation of Pancreatic Adipose Tissue into newly Formed Islets of Langerhans

The aim of this study was to find the effect of long-term food additive monosodium glutamate (MSG) on the tissue of pancreas. For this purpose, two treated groups of adult wistar rats were administered 15 mg/kg body weight for 30 and 75 days respectively. Immediately after sacrificing, specimens of pancreas were collected and fixed. Routine histological processes were carried out to prepare the specimens for light microscopy. Hematoxylin and Eosin, and Gomori aldehyde fuchsin stains were used. The study confirmed that the pancreas had a histological compensatory defense mechanism. In terms of exocrine units, the size of islets of Langerhans were increased due to increase the size of alpha and beta cells and the engorgement of the surrounding blood vessels. The exocrine acini neighboring to islets of Langerhans were engorged with secretion. After 75 days, fusion of some preexisting islets among the exocrine units were recorded. The study firstly focused the light on the pancreatic adipose tissue differentiation to give rise a newly–formed islets of langerhans. The alpha and beta cells of the islets had a well cytological architecture with apparent network of functional blood vessels. Creation of a new generation of beta cells induced by appetizer, may regarded as an important approach in the treatment of type 1 diabetes mellitus. The study concluded that, in small animals, the endocrine mass of pancreatic islets proportionate with the need of insulin. Moreover, adipose tissue act as endocrine tissue and may secreting the hormone insulin. The study declared a positive relationship between exocrine and endocrine units, when the pancreas was subjected to external stressful factor

New dynamic viewing of mast cells in pulmonary arterial hypertension (PAH): contributors or outsiders to cardiovascular remodeling.

In patients with pulmonary arterial hypertension (PAH), mast cells (MCs) are extensively observed around pulmonary vessels. However, their temporal and spatial variation during PAH development remains obscure. This study investigated the dynamic evolution of MCs in lungs and right ventricles (RV) to illuminate their role in pulmonary vascular and RV remodeling. The PAH model was established by a single intra-peritoneal injection of monocrotaline (MCT, 60 mg/kg) in rats. On day 0, 3, 7, 14, and 28 after MCT injection, lung and RV tissues were harvested for staining with hematoxylin and eosin (HE), Gomori aldehyde fuchsin (GAF), toluidine blue (TB) and picrosirius red (PSR). Immunohistochemistry was performed to evaluate the levels of α-SMA, CD68 and tryptase. A simple RV remolding model was produced as well by pulmonary artery banding (PAB). RV tissues were collected to determine the degree of MCs infiltration. After MCT challenge, elevated mean pulmonary arterial pressure (mPAP), increased RV systolic pressure (RVSP), pulmonary arterial media hypertrophy as well as distal vascular muscularization gradually occurred with time. MCs recruitment along with CD68+ macrophages accumulation was observed around distal pulmonary vessels and in alveolar septa. Excessive infiltration and degranulation of MCs were detected in MCT-treated group in lung tissues but not in RV. In addition, no exacerbation of MCs infiltration and degranulation in RV was noted in PAB-treated rats, suggesting few contributions of MCs to RV remodeling. Our findings implied a crucial role of MCs in the remodeling of pulmonary vessels, not RV, which probably through releasing cytokines such as tryptase. The present study enriches the knowledge about PAH, providing a potential profile of MCs as a switch for the treatment of PAH.

Role of DNA methyltransferase 1 in mouse skin aging

To explore the role ofDNA methyltransferase 1 (DNMT1) in mouse skin aging. Methods: Epidermal conditional K14 Cre-mediated DNA methyltransferase 1 (DNMT1) knockout mice (Mut group, n=4) and the littermate normal mice with the same age (WT group) n=4) were used in this study. HE staining was used to detect the pathological changes of skin; the changes of number in the dermal elastic fibers were detected by Gomori aldehyde fuchsin staining, the number of 5-bromo-2-deoxyuridine (BrdU)-labeled transit amplifying cells (TAC) in epidermis were detected by immunohistochemical staining; the number of chlorodeoxyuridine (CldU)-label-retaining cells (LRC) in epidermis were detected by immunofluorescent staining. Results: Compared with the WT group, the skin showed premature aging symptoms in the Mut group concomitant with the decreased epidermal thickness as well as the number of dermal collagen fibers, while the increased dermal elastic fiber fracture. Compared with the WT group, the number of TAC in the epidermis was significantly increased (P<0.05), and the number of LRC was significantly decreased (P<0.05) in the Mut group. Conclusion: The phenotype of skin premature aging in epidermal stem cell conditional DNMT1-knockout mice suggests an important role of DNMT1 in skin aging.

Mucin histochemistry of stomach in metaplasia and adenocarcinoma: An observation

Background:There is a variable pattern of occurrence of gastric carcinomas world-wide, partially reflecting the frequency of various changes of gastric mucosa from, which such neoplasm occur. Many cases of gastric carcinoma originate in the background of chronic gastritis caused by Helicobacter pylori. Subsequent intestinal metaplasia (IM) can be morphologically classified by routine and special histopathological stains.Materials and Methods:The present study was conducted over the 2 years at NRSMC & H, Kolkata. Aims of the present study were to search for evidences of H. pylori infection, classification of different metaplastic and/or malignant changes, identification of types of mucin by mucin histochemistry and their interrelationship in gastrectomy and gastric biopsy specimens (total 70). After obtaining clinical history, radiological and endoscopic findings were noted. After macroscopic study of the specimen, hematoxylene and eosin, southgate mucicarmine, periodic acid schiff-alcian blue (PAS-AB) and gomori aldehyde fuchsin (GAF)/AB staining were performed to classify gastric carcinoma and metaplastic changes and to correlate with staining patterns of mucin.Results:The overall male to female ratio was 2.89:1. Age ranged from 22 years to 78 years and the commonest age group of gastric carcinomas being 41-50 years (26 cases, 37.1%). Gastric adenocarcinoma was found in 61 (87.1%) cases (22.9% were of intestinal type and 77.1% of diffuse type) and only IM was found in 9 (12.9%) cases. Overall the rapid urease test was positive in 18 (25.7%) cases majority of which showing either pure IM or IM associated with intestinal type of gastric carcinoma. All diffuse types of gastric carcinoma (47 cases, 77.1%) were showed PAS positive staining (indicating neutral mucin) whereas in 15 (65.2%) cases of IM columnar cells stained with AB (representing acidic mucin). GAF/AB stain revealed Type II IM in 10 (43.5%) cases and Type III IM in 4 (17.4%) cases.Conclusion:Routine and special histological staining is particularly useful for histological subtyping of gastric carcinomas and IMs.

Cartilage tissue engineering using chondrocyte-derived extracellular matrix scaffold suppressed vessel invasion during chondrogenesis of mesenchymal stem cells in vivo

Loss of chondrogenic phenotypes of tissue engineered cartilage using mesenchymal stem cells (MSCs) in vivo are thought to be influenced by environmental factors like vessel invasion in particular. This study investigated effect of a chondrocyte-derived extracellular matrix (CD-ECM) scaffold on the hypertrophic changes and vessel invasion into tissue engineered cartilage using rabbit MSCs in comparison with a synthetic polyglycolic acid (PGA) scaffold. Rabbit MSCs in CD-ECM or PGA scaffold were differentiated for 1 week in vitro and implanted in the back of nude mice for 6 weeks in vivo. Gross observation showed red stains, indicative of vessel invasion, increased along with the loss of chondrogenic phenotype in safranin-O stains, which was more prominent in the PGA constructs. The area showing loss of chondrogenic phenotypes in safranin-O stain was correlated well with the mineralized area in the von kossa stain and the area with vessel-like structures in the gomori aldehyde fuchsin stain at 6 weeks in terms of their size and distribution. Also, vessel invasion took place more deeply and intensively into the constructs, in accordance with the expression of angiogenic markers (CD31, VEGF-A and HIF-1α) and a macrophage marker (CD68). This phenomenon progressed much more rapidly in the PGA constructs than in the CDECM constructs, and correlated well with the loss of chondrogenic phenotypes. In conclusion, this study showed that tissue engineered cartilage using the CD-ECM scaffold maintained better chondrogenic phenotypes in vivo and showed lower levels of hypertrophic changes and vessel invasion.

Changes in tarsal plate fibrillar collagens and elastic fibre phenotype in floppy eyelid syndrome

The aims of this study are to investigate the expression of the main structural components of the tarsal extracellular matrix (ECM) in floppy eyelid syndrome (FES) focusing on elastic fibres and collagen types I and III, and also to identify possible cell-mediated inflammatory mechanisms in the pathogenesis of this condition. A histopathological case control study was conducted using 30 upper lid specimens from patients with FES and 15 undiseased upper lid control specimens. Structural ECM components were assessed using a combination of immunctorial ataining ohistochemical and techniques including antibodies to collagens I and III, Verhöeff's iron haematoxylin, Gomori's aldehyde fuchsin and Lillie's oxidised aldehyde fuchsin. The contribution of different cellular components of the inflammatory response was investigated by immunohistochemical techniques using antibodies to CD3, CD20, CD68. Slide scoring was performed using a semiquantitative technique on an ordinal scale. Statistical analysis was performed using matched ordinal regression analysis. FES tarsal plate tissue demonstrated a decreased abundance of mature elastic fibres (P ≤ 0.001) and an increased abundance of oxytalan fibres (P = 0.006). Intensity of staining for collagens I (P = 0.012) and III (P < 0.001) was increased. No significant difference in the abundance of CD3, CD20 and CD68 expressing cells was identified. The findings of altered elastic fibre phenotype and collagen accumulation are consistent with an adaptive response to cyclic mechanical loading of the tarsal plate, rather than an aetiological feature. These findings are important in understanding how the tarsal ECM responds to mechanical loading.

Suppression of Experimental Abdominal Aortic Aneurysm in a Rat Model by the Phosphodiesterase 3 Inhibitor Cilostazol

The present experiments sought to determine whether cilostazol, a selective inhibitor of cyclic adenosine monophosphate (cAMP) phosphodiesterase 3 (PDE3), suppressed elastase-induced abdominal aortic aneurysm (AAA) development in a rat model. Male Sprague-Dawley rats (n = 16/each group) were randomly distributed into three groups: sham-, saline-, and cilostazol-. Rats of saline and cilostazol groups underwent intra-aortic elastase perfusion to induce AAAs, while rats of sham-group were perfused with saline. Rats of cilostazol-group received cilostazol treatment (100 mgkg(-1)d(-1)) for the entire experimental period. The areas of the lumen of the aortas at the segment with maximum diameter were measured preperfusion and on d 7, 14 after perfusion. Systolic blood pressure was measured by tail-cuff technique. Aortic tissue samples were harvested on d 14 after intra-aortic perfusion and evaluated by reverse transcription-polymerase chain reaction and Western blot for matrix metalloproteinase-2, 9 (MMP-2, 9), by immunohistochemistry for nuclear factor kappa B (NF-κB), and by Gomori aldehyde fuchsin for elastin. Activity of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and level of reactive oxygen species (ROS) in these samples were also measured. On d 14, rats of saline-group had significantly increased aortic sizes compared with sham-group (P < 0.01), while, cilostazol treatment significantly reduced this increase (cilostazol- versus saline-, P < 0.01) without affecting blood pressure (P > 0.05). The expression of both MMP-2 and MMP-9 and the destruction of elastic fibers in aortic tissues were significantly decreased by cilostazol treatment (P < 0.05), probably through the suppression of NF-κB activation (P < 0.01). Consistently, cilostazol significantly inhibited NADPH oxidase activity (P < 0.01), accompanied by a reduced level of ROS (P < 0.01). Cilostazol retards experimental AAAs development independently of blood pressure reduction possibly by inhibiting proteolysis, inflammation, and oxidative stress. Selective PDE3 inhibition may offer an additional method to pharmacologically inhibit AAAs.

In Situ Protection Against Islet Allograft Rejection by CTLA4Ig Transduction

Immunosuppression focused at or near the graft site would reduce the need for systemic immunosuppression thus educing fewer side effects. We investigated whether locally produced CTLA4Ig, mediated by adenovirus (Adv) transduction of mouse islets, would protect allografts and whether such immunosuppression would remain localized. Adv-CTLA4Ig- or Adv-control-transduced islets were grafted under the kidney capsule of fully allogeneic diabetic mice. CTLA4Ig secreted from the grafted islets was detected by enzyme immunoassay of blood or immunohistochemistry of graft sections. Graft survival was monitored by blood glucose measurement. Histologic scores of graft sections stained with Gomori aldehyde fuchsin to detect insulin granules or hematoxylin-eosin to detect inflammation were used to compare grafts placed at different sites within the same mouse. Adv-CTLA4Ig-transduced islet grafts secreted CTLA4Ig that was detected transiently in the circulation but persistently at the graft site. Survival of these grafts was significantly enhanced compared with control Adv-transduced and untransduced grafts. The kidney graft site availed elucidation of the site of action of CTLA4Ig. Histologic scores indicated that CTLA4Ig-producing grafts were protected by comparison with control grafts on the contralateral kidney. Hence, graft protection was not attributable to general systemic immunosuppression. Indeed, survival of CTLA4Ig-producing grafts was enhanced over control grafts placed at the opposite pole of the same kidney, indicating that graft protection was not solely due to inhibition of priming in the common draining lymph nodes. Islet allografts are protected by locally produced CTLA4Ig-disrupting immune interactions at the effector site.

Effects of intense pulsed light irradiation on the content of collagen fibers, elastic fibers and hyaluronic acid in Kunming mouse skin.

Objective To investigate the effects of intense pulsed light (IPL) irradiation on the content of collagen fibers, elastic fibers and hyaluronic acid in Kunming mouse skin. Methods The dorsal skin of mice was divided into two areas: the right area was irradiated with IPL, and the left remaining unirradiated served as the control. Skin specimens were taken from the back of mice on day 1, 3, week 1, 2, 4 and 8 after the irradiation and subjected to staining with HE, sirius red and Gomori aldehyde-fuchsin for examinations of histological changes, type Ⅰ and Ⅲ collagen fibers and elastic fibers. The hydroxyproline and hyaluronic acid content in skin tissues of mice was determined with ultraviolet spectrophotometry and radioimmunoassay respectively. Results After irradiation, a significant increase was observed in dermal thickness on week 2 (t =4.623, P＜ 0.05), 4, and 8 (t = 3.904, P＜ 0.05), in type Ⅲ collagen fiber (t = 5.129, P＜ 0.05) on week 1,in type Ⅰ and Ⅲ collagen fibers on week 2, 4 and 8 (both P＜ 0.05), in elastic fibers from week 2 to 8 (P ＜0.05), and in hydroxyproline content from week 1 to 8 (all P ＜ 0.05) in the skin of mice compared with unirradiated mice. In detail, dermal thickness increased by 18.71% on week 4, and type Ⅲ collagen fiber by 40.54% in irradiated mice compared with unirradiated mice. Further more, the hyaluronic acid content was elevated from day 1 to 3, but gradually declined from week 1 to 8, and remained statistically higher from day 1 to week 8 (P ＜ 0.05) in irradiated mice compared to unirradiated mice. Conclusion IPL irradiation could induce an increase in the content of collagen fiber, elastic fiber and hyaluronic acid in the dorsal skin of mice. Key words: Intense pulsed light; Collagen; Elastic tissue; Hyaluronic acid; Mice

Elastotic degenerative change and yellowish discolouration in photoaged skin.

One clinical sign of photodamage is a sallow discolouration of the skin, and solar elastotic degenerative change in the upper dermis may cause this change. We have attempted to quantify these phenomena and relate them to each other and to age. Twenty-seven healthy volunteers (age 18 to 61 years) were recruited. We examined the back of the hand of photodamaged individuals and the inner upper arm to demonstrate changes due to ageing. Each site was assessed for cutaneous blood flux using a laser Doppler fluxmeter (PF4000, Perimed UK), and for melanin pigmentation using a Melanin Index meter (Dermotronics Ltd, Cardiff, UK). Skin colour was measured using a diode array spectrophotometer (MCPD-1000, Photal, Japan), which computes CIE coordinates L*, a*, b*. Biopsies from each site were obtained from 13 of the subjects and were processed and stained with Gomori's aldehyde fuchsin. The percentage area of elastic staining material in the dermis was measured using image analysis. Sections were measured in four bands of 200 micron depth, and four fields were measured per band. Neither melanin content nor skin blood flux correlated with age for either skin site. Percentage area of elastosis correlated with age on the exposed site from the uppermost 600 microns of the dermis, (<200 micron depth, r=0.74, P<0.01, 200<depth<400, r=0.57, P<0.05; 400<depth<600, r=0.57, P<0.05). No correlation was found on the unexposed inner upper arm site. On the back of hand site, a linear relationship was found between a parameter derived from the L*, a*, b* coordinates of (b*-5a*) and both age (r=0.904, P<0.001) and percentage area of elastosis of the uppermost 200 microns of dermis (r=0.74, P<0.01). This was not seen for the inner upper arm site. On exposed sites, the coefficient (b*-5a*) correlates with solar elastosis and these both correlate with age, which is related to exposure. This data confirms that solar elastosis accounts for the yellowish discolouration of sun damaged skin, and suggests that the coefficient b*-5a* could be used for the non-invasive quantification of solar elastosis.

Development of the human fetal phreno-esophageal membrane and its role in the anti-reflux mechanism.

The structural development of the phreno-esophageal membrane was studied in 34 human fetuses ranging from 9-26 weeks of age. Horizontal and coronal sections of the lower esophagus, cardia, and diaphragm were stained with Victoria Blue and Gomori's aldehyde fuchsin to show elastic fibers, and with peracetic-aldehyde fuchsin to show pre-elastic, oxytalan, and elastic fibers, being the elastic elements. The membrane was found to be present between the lower esophagus and diaphragm at 9 weeks. The peracetic-aldehyde fuchsin stain showed many elastic elements in this membrane, but the elastic stain showed only a few elastic fibers under 13 weeks. There was no basic structural change of the membrane from 9 to 26 weeks except for an increasing number of fibers and no basic difference from the anatomical arrangement described in the adult with fibers running from the fascial covering of the undersurface of the diaphragm upwards to the esophageal adventitia. Three dimensional observation revealed that the abdominal part of the esophagus was fixed caudally by the posterior part of the membrane. These findings suggest the position-stabilizing function of this membrane and the developmental co-operation between the hiatal crus and the lower esophageal sphincter as an anti-reflux mechanism.

Quantitative Determination of Murine Dermal Elastic Fibers by Color Image Analysis: Comparison of Three Staining Methods

We compared three different staining methods to determine if the dermal elastic fiber content of the HRS/Skh-1 hairless mouse could be accurately measured by color image analysis. Comparisons were made among Kligman's modification of Luna's mast cell stain for elastin, Unna's orcein stain with or without potassium permanganate preoxidation, and Gomori's aldehyde fuchsin stain with potassium permanganate preoxidation. The color image analysis system could be used to identify and quantify murine dermal elastin fibers in sections stained by all three methods. Gomori's aldehyde fuchsin stain with preoxidation demonstrated twice the content of dermal elastic fibers demonstrated by either Kligman's modification of Luna's mast cell stain or Unna's orcein stain with or without preoxidation. Gomori's aldehyde fuchsin method with preoxidation should be considered the stain of choice for evaluating murine dermal elastic fiber content.

Organization of medial elastin at aortic junctions in sheep and lambs.

Aortas from four sheep and three fetal lambs were fixed at physiological pressure in 10% neutral buffered formalin. The regions with branches were serially sectioned in either cross or longitudinal section at 7-micron intervals and stained for elastin with Gomori-aldehyde-fuchsin. A large model of one aortointercostal junction was made from Plexiglas to show that bundles of elastin appeared to be continuous from the aorta into the branch. These bundles were then studied from large photomicrographs of the other junctions. At the intercostals and lumbars, the elastin lamellae ran continuously from the outer third of the media into the branch. There was often an added "pad" of elastin and other acellular material on the flow divider (distal lip). The large muscular branches which arose from the abdominal aorta have much less elastin than the intercostals. In them the aortic elastin appears to merge into a raphe on the proximal and lateral sides of the junction, with a very abrupt transition. A "tongue" of muscle from the branch often penetrated into the media of the aorta distally. Occasionally a small acellular cap was seen on the apex of the flow divider. There were few significant differences between the lambs and the sheep, probably because embryologically the arteries develop very early. The proximal and distal lips of all junctions were easily distinguished from each other, and the small and large branches were also different. We suspect these regions may respond differently to pressure, but we did not test this hypothesis.

INSULINOMA: A CASE REPORT

The case of a 54-year-old woman who was admitted to our hospital in November 1982, with a complaint of hypoglycemic attack and unconsciousness, is reported in the present paper. She was diagnosed as having insulinoma and underwent excision of the cauda corpus pancreatic. The patient had had headache, nausea, vomiting and sometimes a paralysis of both lower extremities since two or three months prior to admission. Insulinoma was suspected from blood chemistry examination, and mass was found in the cauda corpus pancreatis by angio-CT, echography and selective celiac arteriography. A surgical operation was performed for insulinoma. During the operation, an approximately 1×1cm mass was found at a site slightly toward the caudal side from the corpus pancreatis, and excision of the cauda corpus pancreatis was undertaken. The tumor was considered to be an islet cell adenoma histologically. Based on the Gomori aldehyde Fuchsin staining and the enzyme-labelled antibody technique (or peroxidase anti-peroxidase technique) it was considered to be a β-cell tumor (so-called insulinoma). The postoperative course was uneventful, and hypoglycemic symptoms have disappeared. These results lead us to the conclusion that abdominal angiography was useful in the determination of mass localization.

Histological demonstration of elastin-like fibres in the blood vessels of lampreys

1. 1. In contrast to a recent study, our histological investigations have shown that elastin-like fibres are present in the blood vessels of lampreys. 2. 2. The demonstration of these fibres was dependent on appropriate fixation and varied in quality with the three types of stain used. 3. 3. Gomori's aldehyde fuchsin was the only one of the three stains to show the finer details of lamprey elastin-like fibres.

Enzyme-immunohistochemical studies of argyrophil cells in normal islets and islet cell tumors.

Cells stained by the Grimelius or the Hellerstrom-Hellman silver methods or the Gomori aldehyde-fuchsin stain were compared with those stained enzyme-immunohistochemically for several peptide hormones in the same sections of normal islets and of islet cell tumors. It was found that Hellerstrom-Hellman positive cells were completely identical with somatostatin immunoreactive cells, and that Grimelius positive cells correlated well with glucagon, PP and gastrin immunoreactive cells, while aldehyde-fuchsin positive cells were indentical with insulin immunoreactive cells. The useful-ness of these special staining methods is discussed. Immunohistochemically, all islet cell tumors tested revealed a multicellular composition. The multicellularity of islet cell tumors and the occurrence of gastrinomas are discussed.

Structure-staining relationships in histochemistry and biological staining. II. Mechanistic and practical aspects of the staining of elastic fibres.

Correlations between the structural features of dyes and staining performance for elastic fibres were investigated. Dyes studied included the traditional stains (such as Gomori's Aldehyde-Fuchsin and Weigert's Resorcin-Fuchsin), acid dyes used from alkaline aqueous-organic solvent mixtures (the Horobin-James system), and basic dyes used from acidic aqueous-ethanolic mixtures (the Taenzer-Unna system). In all three classes effective elastic fibre stains had large conjugated bond numbers, and were often hydrophobic (i.e. had high Hansch pi values). By choosing dyes with conjugated bond numbers at or over a critical value (25 for the TU system, 35 for the HJ) it is possible to select new and effective dyes for use in the HJ and TU staining systems. Mechanistically these results support the view that for typical commercial dyes and also for the traditional stains van der Waals attractions provide the important contributions to dye-elastic fibre affinities, with hydrophobic bonding playing a subsidiary role. However, supporting the views of Lillie, it was also noted that even hydrophilic dyes of low conjugated bond number could stain elastic fibres, if the dye carried a sufficiently reactive primary amino group as a substituent. The additional substituent groupings needed to generate such reactivity have been specified, for both acidic and alkaline reaction conditions.

Light and ultrastructural relationship between oxytalan fibers in the periodontal ligament of the guinea pig.

The interfaces and the relationships between collagen and oxytalan fibers were observed under light and electron microscopy. Guinea pig periodontal ligament was prepared for light and electron microscopy with perfusion using Peter's buffered formalin for light microscopy and GTA-S-collidine and OSO4 for electron microscopic studies. The tissue for light microscopy was stained with a modified Gomori's aldehyde fuchsin technique, in which pre-oxidization with potassium monopersulfate was carried out before staining so as to demonstrate the oxytalan fibers. EM tissues were routinely stained with lead citrate and uranyl acetate. Two different structural relationships were observed. First, the subcomponents of the collagen and oxytalan fiber types interweave with each other; and, second, some of these two-fiber subcomponents appear attached to each other. These relationships and the known orientation of oxytalan fibers as seen in the periodontal ligament provide insight as to the function of oxytalan fibers. The oxytalan fibers may provide increased structural integrity and increased distribution of forces over a wider area of the periodontal ligament. Because of their close relationship to blood and lymph vessels in the periodontal ligament, they may also help to stabilize these elements by the same structural relationships to collagen fibers.