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PubMed1976

The fine structural localization of S-100 protein in rodent cerebellum.

This report describes the first fine structural locations of S-100 protein in the hamster cerebellum. Innovations in tissue fixation as well as tracer preparation enable localization of S-100 protein to several critical cellular and subcellular sites. Certain neuronal elements, Purkinje cells, contain S-100 protein in both cytoplasm and nucleus. Specific membrane structures including plasma membranes and the nuclear membranes of Purkinje cells are strikingly positive. Localization of S-100 protein to the pericapillary astrocytic endfeet as well as regions of the synapse are of particular biological interest. The clear nuclear localization of the molecule suggests a role in the genetic expression of the developing mammalian brain.

Animals↗

PubMed2006

Histological and ultrastructural analysis of white matter damage after naturally-occurring spinal cord injury.

Detailed analysis of the structural changes that follow human clinical spinal cord injury is limited by difficulties in achieving adequate tissue fixation. This study bypasses this obstacle by examining the spinal cord from paraplegic domestic animals, enabling us to document the ultrastructural changes at different times following injury. In all but one case, injury resulted from a combination of contusion and compression. There was infarction and hemorrhage, followed by gray matter destruction and the rapid development of a variety of white matter changes including axon swelling and myelin degeneration. Axons greater than 5 microm in diameter were more susceptible to degenerative changes, whereas smaller axons, particularly those in the subpial region, were relatively well preserved. Demyelinated axons were seen within 2 weeks after injury and, at later time points, both Schwann cell and oligodendrocyte remyelination was common. More subtle white matter abnormalities were identified by examining sagittal sections, including focal accumulation of organelles in the axoplasm and partial and paranodal myelin abnormalities. These observations serve to validate observations from experimental models of spinal contusion but also highlight the complexity of naturally occurring (ie, clinical) spinal injury. They also raise the possibility that focal abnormalities such as paranodal demyelination may contribute to early axonal dysfunction and possibly to progressive tissue damage.

Animals↗

PubMed1995

[Two-stage excision of extensive cutaneous carcinoma of the face. A retrospective study of 80 patients].

INTRODUCTION: Delayed reconstruction (two-step surgery) comprised of tumor resection and repair three or four days later, after paraffin tissue fixation and histopathological examination, is one of the techniques used for complete excision of spreading cutaneous carcinomas. PATIENTS AND METHODS: In order to evaluate the efficacy and long term prognosis of delayed reconstruction surgery, we carried out a retrospective study of 80 patients treated by this method and (Kaplan- Meier) for correlation with the local recurrence rate: sex, age, anatomic site, histologic type and existence of previous therapy. Long term results have been estimated. Among the 80 patients studied, 76 patients have been followed. The sex-ratio was 0.48. Fifty-two percent of the population was more than seventy years old. Fifty-five percent of the tumors were situated on the nose. In 32,5 p. 100 of the cases, a prior therapy (surgery, electrodessication or radiation therapy) has been carried out. Histological analysis showed 87 p. 100 basal cell carcinomas (of which 26 p. 100 of morpheaform basal cell carcinomas) and 13 p. 100 squamous cell carcinomas. RESULTS: After the first operative step, there was total excision in 69 p. 100 of thecases. In the remaining cases, a second excision was performed with a margin of normal tissue. Recurrences were observed (some precocious recurrences and some late recurrences) in 18.4 p. 100 of the cases. No risk factor correlated significantly with the recurrence rate. However, analysis of the survival graph suggests that the squamous cell carcinomas recurred more often than the basal cell carcinomas. CONCLUSIONS: Although extemporaneous examinations (Mohs' technique) remains the gold standard technique in the management of spreading cutaneous carcinomas of the face, the delayed reconstruction (two-step surgery) is a credible alternative when compared to the recurrence rates reported in the literature with the other techniques (electrodessication, radiation therapy or cryosurgery).

Actuarial Analysis↗

PubMed2003

Basal cell cocktail (34betaE12 + p63) improves the detection of prostate basal cells.

Antibodies against high molecular weight cytokeratin (34betaE12) and p63 are frequently used basal cell markers to aid in the diagnosis of prostate cancer (Pca). Absence of a basal cell marker in an atypical lesion histologically suspicious for cancer supports a diagnosis of Pca. However, absence of basal cells demonstrable by basal cell immunohistochemistry (IHC) is not always conclusive for PCa. Some benign prostatic lesions may have inconspicuous or even lack basal cell lining focally. Technical factors such as tissue fixation and antigen retrieval techniques may also make the detection of basal cells difficult. Improving the sensitivity of current basal cell markers is critical if these tests are being used to help make diagnostic decisions in conjunction with standard histology. In this study, we test the hypothesis that that inclusion of both 34betaE12 and p63 in the same IHC reaction (basal cell cocktail) is advantageous over either marker used alone. One thousand three hundred fifty glands from 9 trans-urethral resectioned of prostate specimens with benign prostatic hypertrophy were used to study the immunostaining intensity and pattern for 34betaE12, p63, and the basal cell cocktail. Basal cell marker expression was scored as strong, moderate, weak, or negative. Basal cell staining was considered complete if 75% of the gland's circumference was positive for the basal cell marker and partial if <25% of the circumference was stained. The mean staining intensity and variance were calculated for 34betaE12, p63, and the basal cell cocktail. A paired test was used to evaluate whether the overall basal cell staining was significantly different between 34betaE12, p63, and the basal cell cocktail. F-test was used to assess the variances for 34betaE12, p63, and the basal cell cocktail. A high-density tissue microarray (TMA) comprising prostate tissue from 103 tumors from men with clinically localized Pca and a separate TMA comprising metastatic hormone-refractory Pca samples from 23 rapid autopsy cases were used to study the aberrant expression of 34betaE12 and p63 in clinically localized and poorly differentiated Pca. The prostate glands in transition zone have variable basal cell staining intensity and pattern with 34betaE12, p63, or the cocktail. Histologically, benign glands lack basal cell lining in 2%, 6%, and 2% of glands with cocktail, 34betaE12, and p63 staining, respectively. The staining variance for the cocktail is significantly smaller than that for 34betaE12 (0.0100 vs 0.1559, p = 0.0008). It is also smaller than that for p63, although a statistical significance has not been reached (0.0100 vs 0.0345, p = 0.099). The basal cell cocktail stains the basal cell layers more intensely than either 34betaE12 or p63 alone, with complete and partial strong basal cell staining in 93% and 1% of benign glands, compared with 55% and 4% with 34betaE12 and 81% and 1% with p63. Complete and partial weak staining is seen in 0% and 0% of benign glands with basal cell cocktail, compared with 8% and 7% with 34betaE12 and 4% and 1% with p63 (p = 0.007 and 0.014 for cocktail vs 34betaE12 and cocktail vs p63, respectively). A total of 2.8% clinically localized Pca had positive 34betaE12 staining and 0.3% had positive p63 staining. Five (22%) of the metastatic Pca is positive for 34betaE12. However, none had p63 expression. The basal cell cocktail had a staining pattern identical to that of 34betaE12. IHC of the prostatic glands from the transition zone is subjected to staining variability that results in frequent variable and occasional negative basal cell staining in histologically benign glands; 34betaE12 is most susceptible, and basal cell cocktail is least susceptible to such variability. Basal cell cocktail not only increases the sensitivity of the basal cell detection, but also reduces the staining variability and therefore renders the basal cell immunostaining more consistent. We recommend this basal cell cocktail for routine Pca diagnostic work-up.

Biomarkers, Tumor↗

PubMed2005

Spatial organization and composition of the mucosal flora in patients with inflammatory bowel disease.

The composition and spatial organization of the mucosal flora in biopsy specimens from patients with inflammatory bowel disease (IBD; either Crohn's disease or ulcerative colitis), self-limiting colitis, irritable-bowel syndrome (IBS), and healthy controls were investigated by using a broad range of fluorescent bacterial group-specific rRNA-targeted oligonucleotide probes. Each group included 20 subjects. Ten patients who had IBD and who were being treated with antibiotics were also studied. Use of nonaqueous Carnoy fixative to preserve the mucus layer was crucial for detection of bacteria adherent to the mucosal surface (mucosal bacteria). No biofilm was detectable in formalin-fixed biopsy specimens. Mucosal bacteria were found at concentrations greater than 10(9)/ml in 90 to 95% of IBD patients, 95% of patients with self-limiting colitis, 65% of IBS patients, and 35% of healthy controls. The mean density of the mucosal biofilm was 2 powers higher in IBD patients than in patients with IBS or controls, and bacteria were mostly adherent. Bacteroides fragilis was responsible for >60% of the biofilm mass in patients with IBD but for only 30% of the biofilm mass in patients with self-limiting colitis and <15% of the biofilm mass in patients with IBS. In contrast, bacteria which positively hybridized with the probe specific for Eubacterium rectale-Clostridium coccoides accounted for >40% of the biofilm in IBS patients but for <15% of the biofilm in IBD patients. In patients treated with (5-ASA) or antibiotics, the biofilm could be detected with 4,6-diamidino-2-phenylindole but did not hybridize with fluorescence in situ hybridization probes. A Bacteroides fragilis biofilm is the main feature of IBD. This was not previously recognized due to a lack of appropriate tissue fixation. Both 5-ASA and antibiotics suppress but do not eliminate the adherent biofilm.

Adult↗

PubMed1998

An approach for studies of mediator-induced leukocyte rolling in the undisturbed microcirculation of the rat mesentery.

1. Although intravital microscopy is the method of choice for observation of inflammatory leukocyte rolling and adhesion in small venules in vivo, a problem with this technique is that surgical exposure of suitable tissues per se triggers the rolling mechanism. In this study, we describe an approach to investigate induction of rolling in undisturbed microvessels. For this purpose, intravital microscopic observation of leukocyte rolling and adhesion in the rat mesentery was combined with histological determination of the intravascular concentrations of polymorphonuclear and mononuclear leukocytes (PMNL and MNL). 2. By relating the histologically determined number of intravascular leukocytes to either microvessel volume or to the erythrocyte concentration, the baseline MNL and PMNL content was found to be 3-6 fold higher in venules than in systemic blood. This increase in microvessel leukocyte concentration did not seem to be related to leukocyte-endothelium interactions, because the leukocyte concentration was similarly elevated in arterioles where rolling and adhesion did not take place. 3. Preparation of the rat mesentery for intravital microscopy time-dependently increased the venular PMNL concentration to over 100 fold the systemic PMNL concentration 45 min after exteriorization of the small intestine. The MNLs were much less responsive to the preparative manipulation. By treatment with the polysaccharide fucoidin (inhibits rolling but not firm adhesion per se), or by use of intravital microscopy immediately before tissue fixation, approximately 90% of the accumulated venular PMNLs were found to represent rolling cells. 4. Intraperitoneal injection of 10(-3) M histamine increased the venular PMNL (but not the MNL) concentration to almost 50 fold the systemic PMNL value. The histamine response did not vary with venular diameter, and the relative contribution of rolling vs firmly adherent cells to the PMNL, accumulation was again approximately 90%. Intraperitoneal injection of leukotriene C4, but not prostaglandin E2, caused a significant increase in venular PMNL concentration. 5. Systemic treatment with the anti-P-selectin monoclonal antibody PB1.3 had no effect on the histamine-induced venular PMNL accumulation (i.e. rolling) in female Wistar or male Sprague-Dawley rats. On the other hand, identical treatment with PB1.3 very effectively inhibited the histamine-induced PMNL response in the mesentery of rabbits. 6. In conclusion, we have shown that a histologically determined increase in leukocyte concentration in rat mesenteric venules may be used as an index of mediator-induced leukocyte rolling if the relative contribution of rolling and firm leukocyte adhesion is first determined, for example by the means described in this study. This relatively simple approach may be very useful for studying various aspects of leukocyte rolling when the 'spontaneous' rolling triggered by preparation of tissues for intravital microscopy is undesirable.

Animals↗

PubMed1987

The immunohistochemistry of gastrointestinal stromal tumors. Evidence supporting an origin from smooth muscle.

To study the histogenesis of gastrointestinal stromal tumors, 79 cases were evaluated for desmin (DES), vimentin (VIM), and S-100 protein immunoreactivity by the avidin-biotin immunoperoxidase procedure on paraffin-embedded, Bouin's-fixed tissue sections. All tumors showed weak vimentin positivity. Trapped non-neoplastic smooth muscle and nerve twigs were often noted, particularly at the tumor periphery. Significant tumor S-100 positivity was not identified in our series. Similarly, glial fibrillary acidic protein (GFAP) immunoreactivity (performed in 11 desmin-negative tumors) was not detected within either gastrointestinal stromal tumors or enteric glial cells. Fifty-three percent (53%) of all gastrointestinal stromal tumors (GIST) displayed positive tumor cell desmin immunoreactivity. All 10 esophageal and all four colorectal tumors were diffusely desmin positive and unequivocal smooth muscle lesions. In contrast, only 17 of 37 (46%) benign and six of nine (67%) malignant gastric tumors were desmin positive. Similarly, four of 10 (40%) benign and one of nine (11%) malignant small-bowel tumors expressed desmin. Several gastric neoplasms with prominent nuclear palisading resembling schwannian Antoni A regions were nonetheless desmin positive. Epithelioid gastric tumors were more frequently desmin positive than nonepithelioid tumors; however, this positivity did not attain statistical significance. Two gastrointestinal stromal tumors that were desmin negative in paraffin-embedded material had detectable antigen in frozen sections. Gastric and small-bowel tumors measuring less than 3 cm were significantly more often desmin positive than those 3 cm or greater. We conclude that the method of fixation, tissue preparation, and immunostaining may significantly affect the expression of desmin. Although the histogenesis of gastrointestinal stromal tumors remains controversial, most of these tumors show evidence of smooth muscle differentiation.

Desmin↗

PubMed2001

[Composite, non-resorbable parietal prosthesis with polyethylene terephtalate-polyurethane (HI-TEX PARP NT): prevention of intraperitoneal adhesions. Experimental study in rabbits].

The authors report an experimental study in the rabbit with a new composite non absorbable mesh in Polyethylene Terephtalate-Polyurethane used for incisional hernia repair in intraperitoneal positioning. This new mesh has one permeable side in polyethylene terephtalate for rapid tissue fixation and another side in polyruethane, hydrophob in order to avoid cell penetration. Eighteen rabbits were operated. A wound was created in aponeurose, muscle and peritoneal abdominal wall. The mesh was placed in intraperitoneal positioning and was taken off at 4, 9 and 13 months for histologic examination and electronic microscopical examination. Tolerance, adhesion, tissular reaction and neoperitoneum formation have been studied. All the meshes were well integrated and without sepsis. In 18% of cases small and monocclusive intraperitoneal adhesions were found. This new composite mesh in intraperitoneal positioning gave good results at medium-term in the rabbit. It's an attractive alternative for incision hernias repair with intraperitoneal mesh.

Abdominal Muscles↗

PubMed2005

GRIP1 in GABAergic synapses.

The glutamate receptor-interacting protein GRIP1 is present in glutamatergic synapses and interacts with the GluR2/3/4c subunits of the AMPA receptors. This interaction plays important roles in trafficking, synaptic targeting, and recycling of AMPA receptors as well as in the plasticity of glutamatergic synapses. Although GRIP1 has been shown to be present at GABAergic synapses in cultured neurons, the use of EM (electron microscopy) immunocytochemistry in the intact brain has failed to convincingly reveal the presence of GRIP1 in GABAergic synapses. Therefore, most studies on GRIP1 have focused on glutamatergic synapses. By using mild tissue fixation and embedding in EM, we show that in the intact brain the 7-PDZ domain GRIP1a/b is present not only in glutamatergic synapses but also in GABAergic synapses. In GABAergic synapses GRIP1a/b localizes both at the presynaptic terminals and postsynaptically, being frequently localized on the synaptic membranes or the synaptic junctional complex. Considerably higher density of GRIP1a/b is found in the presynaptic GABAergic terminals than in the glutamatergic terminals, while the density of GRIP1a/b in the postsynaptic complex is similar in both types of synapses. The results also show that the 7-PDZ and the shorter 4-PDZ domain splice forms of GRIP1 (GRIP1c 4-7) frequently colocalize with each other in individual GABAergic and glutamatergic synapses. The results suggest that GRIP1 splice forms might play important roles in brain GABAergic synapses.

Animals↗

PubMed1990

Detection of HLA-DR on microglia in the human brain is a function of both clinical and technical factors.

Detection of HLA-DR, a class II major histocompatibility antigen, on glial cells is dependent not only on duration and type of tissue fixation and processing, but also on clinical factors. Glial cells labeled by anti-HLA-DR were consistent with microglia by light microscopic and ultrastructural criteria, and were colabeled with other microglial markers, including LN-1, Leu-M5, and leukocyte common antigen (LCA). In young and elderly subjects who died suddenly, anti-HLA-DR labeled microglia in the white matter, but far fewer cells in the gray matter. In subjects who died of chronic debilitating illness, such as Alzheimer's disease and carcinomatosis, anti-HLA-DR labeled numerous microglia throughout both the gray and white matter. In Alzheimer's disease, microglia were aggregated in compact senile plaques, but loosely associated with diffuse amyloid deposits. These results suggest that HLA-DR may be constitutively expressed in white matter, but induced in gray matter microglia in chronic disease states or in association with amyloid deposits.

Aged↗

PubMed2005

Secondary ion mass spectrometry as a tool for investigating radiopharmaceutical distribution at the cellular level: the example of I-BZA and (14)C-I-BZA.

UNLABELLED: Further development of nuclear medicine for imaging and internal radiotherapy demands a precise knowledge of the tissue and cellular distribution of radiopharmaceuticals. Ion microscopy (secondary ion mass spectrometry [SIMS]) may be particularly useful in this respect. We used SIMS to study the biodistribution of the melanoma-targeting molecule N-(2-diethylaminoethyl)-4-iodobenzamide (I-BZA), both in its native state and radiolabeled with (14)C. METHODS: C57BL6/J1/co mice bearing pulmonary colonies of B16 melanoma cells were injected with I-BZA or (14)C-I-BZA. Appropriate tissues were fixed and included in epoxy embedding resin for SIMS studies. The distribution of unlabeled I-BZA was studied by detecting its stable iodine atom ((127)I). (14)C-I-BZA distribution was studied by dual detection of (127)I and (14)C. The time course of I-BZA concentrations at sites of tissue fixation was studied by measuring the signal ratio of (14)C and the naturally occurring isotope (13)C. RESULTS: SIMS showed that I-BZA concentrated in the cytoplasm of tumoral melanocytes (melanoma cells) and in the cytoplasm of tumor-infiltrating macrophages (melanophages). I-BZA was also detected in the cytoplasm of normal melanocytes in the pigmented structures of skin and eye. Interpretation of I-BZA distribution by using electron micrographs of adjacent sections showed that the intracytoplasmic melanin-rich organelles (melanosomes) were responsible for I-BZA retention. The distributions of (127)I and (14)C after (14)C-I-BZA injection were identical, even when I-BZA was separately labeled with (14)C at 2 different positions, indicating the stability of the amide bond of I-BZA. The time course of the (14)C/(13)C ratio in the melanosomes of melanoma cells suggested a retention half-life of about 38 h. CONCLUSION: Contrary to previous suggestions that I-BZA fixes principally to sigma-1 membrane receptors, our results strongly indicate that I-BZA associates with intracytoplasmic melanin pigments. Early I-BZA accumulation, in both melanocytes and melanophages, suggests that this compound fixes to preformed melanin rather than being incorporated during de novo melanin synthesis. These quantitative and qualitative data obtained with I-BZA illustrate the excellent potential of SIMS for studying the biologic fate of radiopharmaceuticals.

Animals↗

PubMed1995

Glutaraldehyde fixation alters the internal shear properties of porcine aortic heart valve tissue.

Glutaraldehyde fixation noticeably alters the mechanical properties of porcine aortic valve tissue, subsequently affecting the function and durability of these tissues when used as prosthetic heart valves. Traditional uniaxial tensile testing techniques do not fully define the mechanical properties and we have devised a new approach to examine the important shear properties of the tissue. Altered shear properties would change the response of the valve tissue as it flexes open and closed. An apparatus combining a high-precision linear actuator with a gram-sensitive load cell was used to measure the shear characteristics of circular punch specimens taken from the center of each valve cusp. The tissue parameters measured showed significant differences between the fixed and fresh tissues. Glutaraldehyde-fixed tissue (n = 16) was about 100 times as stiff as fresh tissue (n = 32) between shear strain values of 0 and 0.2. The fixed tissue also had stress relaxation rates about 60% those of the fresh cusps and had about 70% of the hysteresis loss seen in fresh tissue. These results demonstrated the significant effects of glutaraldehyde fixation on the properties of porcine aortic valve cusp when tested in shear. Such changes could lead to altered tissue function and may increase internal stresses during opening and closing, contributing to valve fatigue.

Animals↗

PubMed2000

Loss of neurons in magnocellular and parvocellular layers of the lateral geniculate nucleus in glaucoma.

OBJECTIVES: To determine whether there is loss of lateral geniculate nucleus relay neurons, which convey visual information to the visual cortex, in experimental glaucoma in monkeys. METHOD: Four cynomolgus monkeys with experimentally induced glaucoma in the right eye (referred to as the glaucoma group) and 5 control monkeys were studied. In both groups, the same conditions of fixation, tissue processing, staining, and measurement were used. In each monkey, the left lateral geniculate nucleus target neurons in magnocellular layer 1 and parvocellular layers 4 and 6, connected to the right glaucomatous eye, were studied. Immunocytochemistry with antibody to parvalbumin was used to specifically label relay neurons connecting to the visual cortex. The number of parvalbumin-immunoreactive neurons was estimated using an unbiased 3-dimensional counting method. The t test was used to compare the experimental and control groups. RESULTS: The mean ( SD) number of neurons in mavnocellular layer 1 was significantly decreased in the glaucoma group compared with the control group (20 692 9567 vs 37 687 8017; P = .02). The mean ( SD) number of neurons in parvocellular layers 4 and 6 was significantly decreased in the glaucoma group compared with the control group (100 141 44 906 vs 174 090 39 136; P = .03). Data are given as the mean SD. CONCLUSION: Significant loss of lateral geniculate nucleus relay neurons terminating in the primary visual cortex occurs in the magnocellular and parvocellular layers in an experimental monkey model of glaucoma. CLINICAL RELEVANCE: Knowledge of the fate of neurons in the central visual system may lead to a better understanding of the nature and progression of visual loss in glaucomatous optic neuropathy.

Animals↗

PubMed1997

Scanning electron microscopy of "fibrillated" and "malacic" human articular cartilage: technical considerations.

Specimens of articular cartilage from human knees with gross evidence of malacia (dull appearance and/or softness) or fibrillation (exposed fibrous strands and/or staining with India ink) were prepared for scanning electron microscopy (SEM) and compared to cartilage from apparently intact regions. Vertical cryofractures were made through the center of each specimen, so the matrix collagen structure and its relationship to surface features could be examined. Soft, dull, malacic cartilage was characterized by the presence of numerous clefts among the collagen fibers within the most superficial region of the cartilage. In one form of this condition, these clefts did not extend through the articular surface. In a second form, usually observed where the tangential zone was normally thin or absent, the free ends of radial collagen fibers were exposed, but the deeper layers were intact. Two forms of fibrillation were also identified. The first is created by separation of the superficial lamellae which curl up from the tangential layer and form frondlike projections above the normal plane of the joint surface. In the second, deep radial fibers are exposed by vertical fissures. This second form is associated with advanced damage to the joint. The early stages of cartilage failure are characterized by debonding among the major collagen fiber tracts. This process may initiate in the deep tangential zone where the radial fibers cross into the surface. The patterns of the degenerative changes are dictated by the original architecture of the collagen matrix. The microscopic findings do not correlate adequately with conventional gross grading. SEM provides useful information about injured articular cartilage.

Adolescent↗

PubMed1997

Megamitochondria in the serous acinar cells of the submandibular gland of the neotropical fruit bat, Artibeus obscurus.

BACKGROUND: As part of a continuing investigation of the comparative ultrastructure of chiropteran salivary glands, we examined the submandibular glands of eight species of neotropical fruit bats in the genus Artibeus. We previously described secretory granules of unusual substructure in the seromucous demilunar cells of this organ in some species in this genus. In the present study, we turned our attention to the serous acinar cells in the same glands. METHODS: Specimens of eight species of Artibeus were collected in neotropical localities. Salivary glands were extirpated in the field and thin slices were fixed by immersion in triple aldehyde-DMSO or in modified half-strength Karnovsky's fixative. Tissues were further processed for electron microscopy by conventional means. RESULTS: In contrast to seromucous cells, which exhibit species-specific diversification in bats of this genus, the secretory apparatus and secretory granules in the serous acinar cells are highly conserved across all seven species. The single exception involves the mitochondria in one species. In this instance, some of the serous cell mitochondria in Artibeus obscurus are modified into megamitochondria. Such organelles usually have short, peripheral cristae; a laminar inclusion is present in the matrix compartment of every outsized organelle. Inclusions of this nature never are present in normal-size mitochondria in the serous cells. None of the megamitochondria were observed in the process of degeneration. CONCLUSIONS: The giant mitochondria in A. obscurus have a matrical structure that is radically different from that of the only other megamitochondria reported to occur in bat salivary glands. The factors that lead to variation in megamitochondrial substructure in different species, as well as the functional capacities of such giant organelles, are unknown.

Animals↗

PubMed1982

Systemic mast cell disease: a clinical and hematopathologic study of 26 cases.

Systemic mast cells disease (SMCD) is an uncommon disorder that constitutes approximately 10% of all mastocytoses. Diagnosis requires a substantial degree of clinical suspicion, which may not be present if characteristic skin lesions of urticaria pigmentosa are not observed. Lack of well-defined histopathologic features for the disease have delayed or prevented the diagnosis of SMCD. An initial diagnosis of "myeloproliferative disorder," chronic granulocytic leukemia, or myelofibrosis is frequently made. Study of the clinical and pathologic features of 26 cases of SMCD indicated that affected patients are generally middle aged and may have had urticaria pigmentosa for many years. Gastrointestinal symptoms are common, and splenomegaly and hepatomegaly along with radiographic evidence of generalized bone disease are usually noted. Hematologic factors are highly variable. Characteristic histopathologic features of SMCD are described for bone marrow, lymph nodes, liver, and spleen. The authors consider tissue fixation and staining methods to help identify mast cell lesions.

Adult↗

PubMed1994

Four varied cases of intravascular lymphomatosis and a literature review.

BACKGROUND: Intravascular lymphoma (IVL) is an uncommon malignancy defined pathologically by neoplastic proliferation of lymphoid cells within the lumens of capillaries, small veins, and arteries, with little or no adjacent parenchymal involvement. The nature of IVL has been the subject of considerable controversy. Recent immunohistochemical studies have demonstrated clearly that the tumors bear the immunophenotype of neoplastic lymphoid cells of either B-cell or T-cell lineage. IVL commonly affects the central nervous system, resulting in progressive dementia and multiple neurologic deficits; skin is the second most common site of involvement, in the form of cutaneous plaques and nodules. METHODS: In a retrospective review of all cases of non-Hodgkin's lymphoma seen at our institution, four cases of IVL were identified. Case 1 was fixed in methacarin, and Cases 2-4 were fixed in 10% formalin. Standard fixation, tissue processing, sectioning, and hematoxylin and eosin staining were used. Immunophenotypic studies were performed using a modified avidin-biotin complex technique. The specimen in Case 1 was stained by Giemsa stain using standard techniques. RESULTS: Four cases of IVL are presented. One patient experienced hypoxemia and fevers of unknown origin; the second, dementia and a vasculitislike illness; the third rapidly progressive dementia, nonlocalizing neurologic deficits, and panhypopituitarism; the fourth Kaposi-like skin lesions. Case 1 relapsed shortly after completing chemotherapy. Salvage chemotherapy has yielded good initial response. Autopsy findings in cases 2, 3 and 4 confirmed IVL in many vessels, including the brain, lung, liver, heart, gastrointestinal tract, glomerulus, central nervous system, and skin. Malignant lymphoid cells marked as B-cells in all cases. CONCLUSIONS: Unusual and interesting clinical presentations may occur in patients with IVL. The medical literature indicates that few cases are diagnosed ante mortem. Although isolated patients may respond favorably to chemotherapy, most will deteriorate rapidly and the diagnosis of IVL not contemplated until necropsy.

Adult↗

PubMed1978

Lymphatic vessels of the mammalian heart.

An in situ heart lung preparation was developed to label lymphatics of the actively beating dog heart with subsequent fixation by vascular perfusion. Immediately after interstitial injections of trypan blue and colloidal carbon, a rich plexus of lymphatic vessels was visualized in the epicardium of the actively beating heart. With this method of fixation, tissue preservation is generally excellent and uniform throughout the heart. In thin sections examined with the electron microscope, lymphatic vessels are easily recognized by the content of plasma proteins which is preserved as an electron dense precipitate that is evenly dispersed throughout the lumen. An extensive plexus of thin walled lymphatic vessels is observed throughout the epicardial, myocardial and subendocardial regions. Numerous anchoring filaments are observed closely apposed to the abluminal endothelial surface which extend into the surrounding connective tissue. The distribution and ultrastructure of the cardiac lymphatic vessels are discussed in relation to their role in the removal of interstitial fluid from the heart.

Animals↗