The circulating hemocytes of Culexpipiens and Aedesaegypii: Cytology histochemistry,hemograms and functions

The hemocyte types of $\text{Culex}$$\text{pipiens}$ and $\text{Aedes}$$\text{aegypti}$ larvae are described. Plasmatocytes and oenocytoids are present and are involved in phagocytosis and melanin production, respectively. Comparisons are made with the findings of previous authors and together with modifications in the hemogram following parasitization by the nematode, $\text{Neoplecta}$$\text{carpocapsae}$, indicate that the hemocytes are also involved in encapsulation reactions.     

Regulation of hydrogen peroxide release in circulating hemocytes of the planorbid snail Biomphalaria glabrata

Biomphalaria spp. serve as obligate intermediate hosts for the human blood fluke Schistosoma mansoni. Following S. mansoni penetration of Biomphalaria glabrata, hemocytes of resistant snails migrate towards the parasite, encasing the larva in a multicellular capsule resulting in its destruction via a cytotoxic reaction. Recent studies have revealed the importance of hydrogen peroxide (H(2)O(2)) and nitric oxide (NO) in parasite killing [Hahn UK, Bender RC, Bayne CJ. Killing of Schistosoma mansoni sporocysts by hemocytes from resistant Biomphalaria glabrata: role of reactive oxygen species. J Parasitol 2001;87:292-9; Hahn UK, Bender RC, Bayne CJ. Involvement of nitric oxide in killing of Schistosoma mansoni sporocysts by hemocytes from resistant Biomphalaria glabrata. J Parasitol 2001;87:778-85]. It is assumed that H(2)O(2) and NO production is tightly regulated although the specific molecules involved remain largely unknown. Consequently, the potential role of cell signaling pathways in B. glabrata hemocyte H(2)O(2) production was investigated by evaluating the effects of specific inhibitors of selected signaling proteins. Results suggest that both ERK and p38 MAPKs are involved in the regulation of B. glabrata H(2)O(2) release in response to stimulation by PMA and galactose-conjugated BSA. However, the involvement of the signaling proteins PKC, PI(3) kinase and PLA(2) differs between PMA- and BSA-gal-induced H(2)O(2) production.     

Immune elimination and enhanced antibody responses: functions of circulating IgA.

Passively transferred MOPC 315 IgA myeloma protein accelerated the elimination of DNP-ovalbumin, to which the myeloma protein bound with antibody-like affinity, from the circulation and increased the subsequent antibody response to hapten and to carrier, when injected with or without adjuvant.     

Matrilin-like molecules produced by circulating hemocytes of the zebra mussel (Dreissena polymorpha) upon stimulation

Since invading the Great Lakes basin, USA, in 1980s, the zebra mussel (Dreissena polymorpha) has caused significant economic and ecologic devastation. The absence of major diseases led to the belief that zebra mussel may have extraordinary host defense mechanisms. This study was undertaken in order to better understand zebra mussel hemocyte functions. A suppressive subtraction hybridization (SSH) cDNA library was constructed from naïve and stimulated hemocytes. Stimulation was performed using a mixture of lipopolysacchride (LPS), peptidoglycan (PGN), and zymosan (ZYM). In the stimulated hemocyte SHH cDNA library, 55 assembled ESTs were differentially expressed. These ESTs contained two putative immune- related molecules, namely, matrilin and agglutinin, three house-keeping genes, six cell metabolism/development genes, and 44 ESTs without putative functions. One of the putative adhesive molecules (CN-29, accession number: AM503947) was predicted to have homology with matrilins including the Von Willebrand Factor A (VWA) domain, which was identical to a matrilin molecule recently reported from the freshwater snail, Biomphalaria glabrata. Preliminary evidence suggests that the zebra mussel matrilin-like molecule is inducible upon hemocyte stimulation.     

The endothelial glycocalyx: composition, functions, and visualization

This review aims at presenting state-of-the-art knowledge on the composition and functions of the endothelial glycocalyx. The endothelial glycocalyx is a network of membrane-bound proteoglycans and glycoproteins, covering the endothelium luminally. Both endothelium- and plasma-derived soluble molecules integrate into this mesh. Over the past decade, insight has been gained into the role of the glycocalyx in vascular physiology and pathology, including mechanotransduction, hemostasis, signaling, and blood cell–vessel wall interactions. The contribution of the glycocalyx to diabetes, ischemia/reperfusion, and atherosclerosis is also reviewed. Experimental data from the micro- and macrocirculation alludes at a vasculoprotective role for the glycocalyx. Assessing this possible role of the endothelial glycocalyx requires reliable visualization of this delicate layer, which is a great challenge. An overview is given of the various ways in which the endothelial glycocalyx has been visualized up to now, including first data from two-photon microscopic imaging.     

Characterization of the circulating hemocytes in mud crab (Scylla olivacea) revealed phenoloxidase activity

This study focused on an isolation and characterization of the circulating hemocytes in mud crab, Scylla olivacea. Isolation of specific cell types of hemocytes from crab hemolymph was accomplished by using 60% Percoll density gradient centrifugation. Four separated bands of the hemocytes were successfully obtained. Characterization of these isolated hemocytes by light microscope using trypan blue-rose bengal staining, rose bengal–hematoxilin staining, and phase contrast revealed four distinct types of hemocyte cells. Using their specific morphology and granularity, they were identified as hyaline cell (HC), small granular cell (SGC), large granular cell (LGC) and mixed granular cell (MGC). Transmission electron microscopy (TEM) revealed more details on specific cell size, size of cytoplasmic granule, and nuclear to cytoplasmic ratio, and confirmed the classification. Relative abundance of these cells types in the hemolymph of an adult crab were 15.50 ± 8.22% for HC, 55.50 ± 7.15% for SGC, 13.50 ± 5.28% for LGC, and 15.50 ± 3.50% for MGC. Proteomic analysis of protein expression for each specific cell types by two-dimensional electrophoresis identified two highly abundant proteins, prophenoloxidase (ProPO) and peroxinectin in LGC. Determination of phenoloxidase (PO) activity in each isolated cell types using in vitro and in situ chemical assays confirmed the presence of PO activity only in LGC. Based on an increased PO activity of crab hemolymph during the course of White Spot Syndrome Virus (WSSV) infection, these results suggest that prophenoloxidase pathway was employed for host defense mechanism against WSSV and it may link to the role of large granular hemocyte.     

The Paris system of Reporting Urinary Cytology: Strengths and opportunities

The Paris system for reporting urinary cytopathology (TPS) was created to address inherent weaknesses inherent in the practice of urinary cytopathology. While urothelial cytology has always performed well at finding high grade, genetically unstable urothelial carcinoma, it performs poorly when it comes to detecting low‐grade urothelial neoplasia. TPS intends to improve the utility of urothelial cytology by focusing on what is important, high‐grade urothelial carcinoma. This article is a snapshot of the current state of TPS as it heads into its second edition. Successes are described and further developments are considered.     

Recognition of xenogeneic proteins by the blue crab: dissociation of the clearance and degradation reactions and lack of involvement of circulating hemocytes and humoral factors

Blue crabs clear foreign proteins from the circulation to the gills in a manner that can be explained by postulating the participation of a finite number of naturally occurring quasi-specific receptors. The rate of this clearance reaction is not increased by previous exposure to the foreign protein although recovery to the normal rate of clearance after high level blockade is quite rapid. The cleared foreign proteins are degraded in the gills in a relatively nonspecific fashion suggestive of a clear distinction between the clearance and degradation reactions. The results of perfusion experiments indicate that neither circulating hemocytes nor specific humoral factors are responsible for the foreign protein clearance reaction in blue crabs. Thus it is concluded that fixed cells, most likely in the gills, are responsible for this means of dealing with nonself proteins in blue crabs and possibly other crustaceae .     

The cytoarchitecture, histochemistry and projections of the tuberomammillary nucleus in the rat

The normal morphology, efferent projections and possible neurotransmitter content of neurons in the tuberomammillary nucleus (caudal magnocellular nuclei of Bleier et al.) [Bleier, Cohn and Siggelkow (1979) In Anatomy of the Hypothalamus, Vol. 1, pp. 137-220] have been examined in the adult male rat. In Nissl-stained sections, the nucleus can be divided into a dorsomedial, ventral and diffuse part, each of which consists of large, darkly stained neurons cradling the mammillary body. The ventral part is by far the largest and consists of some 2500 neurons on each side of the brain. Immunohistochemical studies indicate that a majority of the large neurons in all three parts of the nucleus stain with antisera against glutamate decarboxylase and [Met]enkephalyl-Arg6-Phe7 heptapeptide and that a smaller subset of these neurons (about 10%) also stain with an antiserum against substance P. Single injections of retrogradely transported fluorescent tracers were made into 18 different sites in 86 animals and the results indicate that all three parts of the tuberomammillary nucleus on one side of the brain send fibers to or through various parts of the neocortex, hippocampal formation, amygdala, basal ganglia, thalamus, superior colliculus and cerebellum on both sides of the brain and that the projection neurons are not organized in a highly topographic way. Injections of two different fluorescent tracers in the same animal indicate that individual neurons in the nucleus may give rise to both ascending and descending projections, as well as projections to widely divergent parts of the forebrain. Together with previous results, this evidence suggests that the tuberomammillary nucleus has widespread projections to the numerous brain structure located in the forebrain and in the caudal medulla (it may not project to the spinal cord), and that its axons may release a mixture of neuroactive substances including gamma-amino butyrate and several peptides. Although its functional significance remains to be investigated, morphological evidence suggests that the tuberomammillary nucleus may constitute one of a series of neurotransmitter-specific cell groups in the brainstem and basal forebrain with diffuse efferent projections that may be involved in the modulation of attention or behavioral state, rather than the processing of specific sensory or motor information.     

The evaluation of human lymph nodes, using plastic sections and enzyme histochemistry

The histopathologic evaluation of the human lymph node is frequently difficult. Although immunologic markers have been used recently in such evaluations, enzyme histochemical markers have been used only sporadically since their introduction in the 1930s. One reason that they have been neglected is that they have required the use of frozen sections. This article describes the use of a plastic embedding technic with enzyme histochemistry in a series of more than 300 reactive human lymph nodes. Enzyme histochemical reactions were preserved very well and could be localized extremely well with this technic, which allowed the identification of histologic features not readily apparent by other means. The technic may be valuable in evaluating both reactive and neoplastic lymph nodes.     

Renal clear cell tumors: morphology, histochemistry, ultrastructure, differential diagnosis

To define criteria for differential diagnosis of renal clear cell adenoma and grade I clear cell carcinoma, morphological, morphometric, histochemical, and ultrastructural studies were undertaken to examine 30 renal clear cell tumors (18 carcinomas and 12 adenomas). No morphological, morphometric, histochemical, and ultrastructural differences were found between the tumors, but the average tumor size was smaller in the adenoma than in the carcinoma. Clinically and morphologically, clear cell adenoma should be classified as grade I clear cell carcinoma of stage I, which has a relatively favourable prognosis by virtue of its small node sizes.