bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of early vascular damage in the pathogenesis of gastric haemorrhagic mucosal lesions induced by indomethacin in rats
Authors: GYÖMBER EDIT , VATTAY P. , SZABO S. , RAINSFORD K.D.
Published: November 2003

Early vascular injury is a key element in the pathogenesis of gastric haemorrhagic mucosal lesions which develop rapidly after intragastric (i.g.) administration of ethanol, HCl or NaOH. The sequence of vascular events leading to gastric lesions has not, however, been investigated in detail with ulcerogenic non‐steroidal anti‐inflammatory drugs such as indomethacin (IND). Accordingly, experiments were performed in rats using the vascular tracer Monastral blue to assess whether vascular lesions precede and are subsequently associated with mucosal lesions induced by oral (p.o.) or subcutaneous (s.c.) administration of IND. Fasted female Sprague–Dawley rats (150–180 g) were given IND either at 100 mg/kg, p.o. or 200 mg/kg s.c. and killed 15, 30, 120 or 240 minutes later. Monastral blue, 3% saline 1 ml/kg, was injected intravenously under ether anaesthesia 3 minutes before autopsy and the formalin fixed, glycerol cleared stomachs were examined microscopically for deposition of the dye particles on damaged blood vessels. The percentage area of Monastral blue labelled vessels (measured by stereomicroscopic planimetry) at 15 minutes after oral IND was 10.1 ± 1.5% (mean ± s.e.m.) of glandular stomach and increased progressively to 64.5 ± 3.0% at 240 minutes. Gastric haemorrhagic lesions (also measured by stereomicroscopic planimetry) were first evident at 30 minutes (0.2 ± 0.03%; mean ± s.e.m.), and developed progressively to 2.0±0.3% total area of glandular mucosa at 240 minutes. Subcutaneous injection of IND resulted in a delayed time of onset for the appearance and the extent of mucosal lesions (first appearing at 120 minutes, 0.1 ± 0.03% area) compared with that from oral administration of the drug, but as with oral IND the vascular damage (first appearance at 15 minutes, 7.5 ± 3.6%) clearly preceded the occurrence of gastric lesions. The observations of microvascular dye labelling were paralleled by observations of the electronmicroscopic appearance of endothelial cell disruption in the region adjacent to superficial mucous cells and accumulation of red blood cells in the interstitium at 20–60 minutes. We conclude that vascular injury precedes haemorrhagic mucosal damage in the pathogenesis of IND‐induced acute gastric mucosal lesions.
Relation between distribution of viral RNA and development of histopathological changes in encephalomyocarditis virus‐induced orchitis in mice
Authors: UENO AITO , TAKEDA MAKIO , HIRASAWA KENSUKE , ITAGAKI SHIN’ICH , DOI KUNIO
Published: November 2003

The relation between the distribution of viral RNA and the development of histopathological changes was investigated in the early stage of encephalomyocarditis (EMC) virus‐induced orchitis in mice. Signals of viral RNA were first detected by in situ hybridization in a few Sertoli cells in almost intact germinal epithelia at 2 days post‐inoculation (d.p.i.). The number of Sertoli cells bearing signals of viral RNA increased at 3 d.p.i. when mild degenerative changes were exceptionally found in germinal epithelia. Signals of viral RNA came to be detected not only in Sertoli cells but also in a small number of germinal cells and spermatogonia at 4 d.p.i. when mild to moderate degenerative changes developed in germinal epithelia, resulting in desquamation of degenerated cells. At the same time, virus‐like particles were observed by electron‐microscopy in the degenerated and desquamated germinal cells. At and after 5 d.p.i., luminal obstruction with cellular debris and inflammatory cells was generally found. These results suggest that EMC virus carried to seminiferous tubules via the blood first attacks Sertoli cells and then damages germinal cells and spermatogonia.
The expression of tumour necrosis factor in the hypothalamus after treatment with lipopolysaccharide
Authors: LIU LAN , KITA TOSHIRO , TANAKA NORIYUKI , KINOSHITA YOSHIMASA
Published: November 2003

To investigate the effects of tumour necrosis factor (TNF) in the hypothalamus, Wistar rats received an intravenous administration of lipopolysaccharide (LPS) at a dose of 3.0 mg/100 g. Concentrations of TNF‐α in the cerebral liquor and blood sera rapidly increased at 30 minutes after administration of LPS, rose to the maximum level at 1 hour, and then gradually decreased. Using horse‐radish peroxidase as a tracer, a transient increase in paracellular permeability throughout the tight junctions of the ependymal cell layer covering the third ventricle was observed by electron microscopy at 30 minutes and in that of the capillary endothelium at 1 hour after administration, respectively. Following LPS administration, TNF was preferentially localized by immunoelectron microscopy in the tight junctional area of the ependymal cell layer and the capillary. These data indicate that TNF, synthesized in the ependymal cell layer, induces a deterioration in the cerebrospinal fluid–brain barrier and subsequently in the blood–brain barrier. The present study suggests that oedematous changes in the hypothalamic areas determined by ultrastructural and magnetic resonance analyses were mainly due to TNF conveyed from the ependymal cell layer to the hypothalamus after administration of LPS.
Dengue virus‐induced cytotoxin releases nitrite by spleen cells
Authors: MUKERJEE RUMA , MISRA ANITA , CHATURVEDI U.C.
Published: November 2003

Dengue type‐2 virus (DV) infection in mice induces T cells to produce a cytokine, the cytotoxic factor (CF), which induces H2‐A positive macrophages to produce another cytokine, cyotoxin (CF2), which amplifies its cytotoxic effects on target cells. The present study was undertaken to investigate the production of nitrite (NO−2) by the spleen cells of mice in vitro and in vivo following inoculation of CF2. Maximum NO−2 production occurred at 1 hour after inoculation of 100 μg CF2. Pretreatment of CF2 with anti‐CF2‐antisera (CF2‐As) inhibited the production of NO−2. Pretreatment of the spleen cells with NG‐monomethyl‐l‐arginine (NMA) or with arginase inhibited NO−2 production. The NO−2 production was diminished in a dose dependent manner by treatment of spleen cells with the Ca2+ channel blocking drug, nifedipine and Zn2+ as ZnSO4. The findings of the present study thus demonstrate that CF2 induces production of NO−2 in the spleen cells in a CA2+‐dependent manner which may be a mechanism of target cell killing.
Release of reactive oxygen intermediates by dengue virus‐induced macrophage cytotoxin
Authors: MISRA ANITA , MUKERJEE RUMA , CHATURVEDI U.C.
Published: November 2003

Dengue type 2 virus (DV) induces a subpopulation of T lymphocytes of mice to produce a cytokine, cytotoxic factor (mCF), which induces H‐2A positive macrophages to produce macrophage cytotoxin (CF2). The present study was undertaken to investigate the mechanism of cytotoxicity of CF2. It was observed that CF2 induced production of superoxide anion (O−2) and hydrogen peroxide (H2O2) by the spleen cells of mice in vitro and in vivo. The maximum production of O−2 (260 ±10 nM/4 × 106 cells) was at 45 minutes while that of H2O2 was at 90 minutes after inoculation of CF2. Pretreatment of mice or spleen cells with anti‐CF2‐antisera inhibited O−2 and H2O2 production in a dose‐dependent manner. Superoxide dismutase (SOD) inhibited O−2 production and cytotoxicity while H2O2 production was increased by increasing SOD concentration in the culture. This indicated that O−2 production is necessary for the cytotoxic activity of CF2. Pretreatment of the cells with Ca2+ channel blocking drugs, nifedipine or verapamil, inhibited CF2‐induced O−2 and H2O2 production in a dose‐dependent manner. We have shown earlier that the cytotoxic activity of CF2 is known to be Ca2+ dependent and CF2‐induced production of nitrite and the cytotoxicity is inhibited by NG‐monomethyl‐L‐arginine. Thus, it is suggested that O−2 and nitrite are necessary for cell killing by CF2 in a Ca2+ manner and the killing may possibly be by generation of peroxynitrite.
Gene knockout mice as investigative tools in pathophysiology
Authors: RYFFEL BERNHARD
Published: November 2003

An overview is given of the phenotype of mice with distinct deletions of genes for cytokines and some related proteins, which occur either naturally or as a result of homologous recombination. The use of such knockout mice for investigation of the pathophysiology of experimental disease is summarized. Understanding of the role of a given cytokine in pathogenesis has therapeutic implications, as the pathology may be prevented or attenuated by inhibition of the synthesis, release or activity of that cytokine.
Transforming growth factor‐β production during the development of renal fibrosis in rats with subtotal renal ablation
Authors: COIMBRA T.M. , CARVALHO J. , FATTORI A. , DA SILVA C.G.A. , LACHAT J.J.
Published: November 2003

The histologic changes observed in the remnant kidney model include progressive mesangial expansion with collapse of capillary lumina, interstitial fibrosis and mononuclear cellular infiltration. Transforming growth factor‐beta (TGF‐β1) is an important regulator of extracellular matrix formation. The purpose of this study was to investigate the production and distribution of TGF‐β1 in the kidney during the development of glomerulosclerosis and renal fibrosis in rats with subtotal renal ablation. Eighty‐two female Wistar rats weighing 180–220 g were divided into two groups: 49 rats were subjected to 5/6 renal ablation and 33 to sham operation. Urinary albumin excretion, blood pressure and glomerular filtration rate (GFR) were evaluated after the surgical procedure. We also performed histology and immunohistochemistry and determined mRNA for TGF‐β1 in the kidneys of these rats 8, 15, 30 and 90 days after operation. The results showed progressively higher immunohistochemical TGF‐β1 staining in rats with subtotal renal ablation. Cortical renal content of TGF‐β1 mRNA was also higher in these animals and peaked at day 15.

The existence of a temporal association between glomerulosclerosis, interstitial fibrosis and intense mononuclear cellular infiltration on the one hand and higher immunohistochemical TGF‐β1 staining in the renal cortex on the other show that this polypeptide may contribute to the development of renal fibrosis in this model.
Lymphohaematopoietic abnormalities and systemic lymphoproliferative disorder in interleukin‐2 receptor γ chain‐deficient mice
Authors: Ikebe Mika , Miyakawa Kazuhisa , Takahashi Kiyoshi , Ohbo Kazuyuki , Nakamura Masataka , Sugamura Kazuo , Suda Toshio , Yamamura Ken‐ichi , Tomita Kimio
Published: November 2003

Interleukin‐2 (IL‐2) receptor γ chain‐deficient mice with a truncated mutation showed the absence or severe reduction of natural killer cells, decreased numbers of T‐ and B‐ cells, marked hypoplasia of the thymus and peripheral lymphoid tissues, defective formation of lymphoid follicles and germinal centre in the peripheral lymphoid tissues, and the absence of Peyer's patches in the intestinal mucosa. In addition, marked splenomegaly with extramedullary haematopoiesis, increased level of IgM and decreased levels of IgG and IgE in serum, severe reduction of conventional B cells (B‐2) in the peripheral lymphoid tissues, the presence of IgM‐producing CD5+ B cells (B‐1) and their differentiation into plasma cells and Motto cells in the spleen, and increased production and differentiation of macrophages in various tissues were found in the mutant mice. However, the development of both marginal metallophilic macrophage populations in the spleen and of their related macrophages in the other tissues of the mutant mice was severely impaired. All these abnormalities seem to be induced by the loss‐of‐function of the IL‐2 receptor γ chain. From 8 weeks of age on, inflammatory changes occurred in the intestines, mesenteric lymph nodes, lungs, liver, and kidneys of the mutant mice. Besides the absence of Hassall’s corpuscles, thymic cysts were frequently observed in the mutant mice. These pathological abnormalities suggest that the γ chain is implicated not only in lymphoid and haematopoietic development but also in thymic epithelial cell ontogeny.
Modification of spontaneous renal lesion of APA hamsters by streptozotocin‐induced diabetes
Authors: NISHIDA ETSUKO , YAMANOUCHI JUN , OGATA SEIYA , DOI KUNIO , ITAGAKI SHIN‐ICHI
Published: November 2003

Syrian hamsters of the APA strain (APA hamsters) develop spontaneous mesangial thickening in the renal glomeruli from an early age. They also develop focal and segmental glomerulosclerosis (FSG) at and after 6 months of age. In this study, histopathological, immunohistochemical and lectin histochemical examinations were conducted to clarify the modification of the spontaneous renal lesions of APA hamsters by streptozotocin(SZ)‐induced diabetes. Histopathological analysis revealed that the expansion of the mesangial region was more prominent and the thickening of the glomerular basement membrane (GBM) was weaker in SZ‐treated animals than in non‐treated ones. Immunohistochemical analysis suggested that type IV collagen and laminin were involved in the expansion of the mesangial region and thickening of the GBM. In lectin histochemical analysis, podocytes, capillary endothelial cells, GBM and a part of mesangial region of SZ‐treated animals were positive for RCA120 and GSL‐I with neuraminidase‐pretreatment although they were negative for these lectins in non‐treated animals. These results suggest that the spontaneous glomerular lesion of APA hamsters is modified qualitatively and quantitatively by SZ‐induced diabetes.
The intestinal epithelial stem cell: the mucosal governor
Authors: POTTEN CHRISTOPHER S. , BOOTH CATHERINE , PRITCHARD D. MARK
Published: November 2003

All epithelial cells in the small and large intestine are thought to originate from stem cells located towards the base of the crypts of Lieberkühn. To‐date, there are no specific intestinal stem cell markers, hence stem cell properties can only be inferred. A range of experimental techniques have been employed including cell position mapping, radiation regeneration (clonogenic) assays, chimeric and transgenic mice. This review discusses the implications of experiments performed using these techniques in order to deduce the number, location and functional properties of stem cells. Stem cell homeostasis is maintained by cell proliferation and death ‘through apoptosis’. The various growth and matrix factors and genes which may control these processes, and be important for stem cell function, are discussed along with their carcinogenic and clinical implications.
Effect of maternal cholestasis on the kinetics of bile acid transport across the canalicular membrane of infant rat livers
Authors: SERRANO MARIA A. , MONTE MARIA J. , MARTINEZ‐DIEZ MARIA C. , MARIN JOSE J. G.
Published: November 2003

A reversible impairment in the ability of the liver to secrete cholephilic compounds has been reported to exist in infant rats born from mothers with surgically induced complete cholestasis during the last third of the pregnancy. Canalicular plasma membranes (CPM) were purified from livers obtained from 4 and 8 week‐old offspring of healthy or cholestatic rats. Using radiolabelled glycocholic acid (GC) and a rapid filtration technique, bile acid transport by CPM vesicles in the presence of 3 mM ATP plus an ATP‐regenerating system was measured at varying substrate concentrations. Kinetic parameters were calculated by nonlinear regression analysis. Similar values for the apparent affinity constant (Kt) were found in all experimental groups (approximately 350 μM). The value of the maximal velocity of the transport (Vmax) was similar for CPM obtained from control animals at 4 or 8 weeks of age (approximately 1.5 nmol/20 s/mg protein). In the offspring of cholestatic mothers the Vmax value was not different from that found in control animals as far as 4 week‐old rats were concerned. However, Vmax in the 8 week‐old group from cholestatic mothers was two‐fold higher than that found in the rest of the experimental groups. Thus, the efficiency of transport, defined as Vmax/Kt, was very similar in all experimental groups, except in the group of 8 week‐old offspring of cholestatic mothers, where this value was 60% higher. Isolated livers obtained from this group were able to secrete a tracer dose of radiolabelled GC (11.25 nmol) into bile significantly faster than isolated livers obtained from control animals of the same age (8 weeks). In sum, these results indicate that, in young infant rats (4 week‐old), in which the maximal secretion rate for bile acids was reduced by maternal cholestasis during pregnancy, the kinetics of ATP‐dependent bile acid transport across the canalicular membrane were not affected. By contrast, in older infant rats (8 week‐old), in which the overall ability of the liver to secrete bile acids seems to be restored to normality, the efficiency of the canalicular transport system was actually enhanced. This suggests the existence of compensation at the level of the canalicular membrane transfer and thus that there is another hitherto unidentified mechanism involved in bile acid secretion.
Lung stem cells
Authors: OTTO W.R.
Published: November 2003

The identity of putative stem cells in tracheobronchial, bronchiolar and alveolar compartments is reviewed. Their developmental appearance is described, as is the experimental evidence for their ability to repopulate areas of damage caused by noxious agents such as ozone, mineral fibres, chemicals and mechanical or enzymatic removal. Factors affecting pulmonary cell proliferation and differentiation are considered. The role played by these cells in carcinogenesis is also discussed, with consideration of the position of neuroendocrine cells in this process.
Stem cells in prostatic epithelia
Authors: FOSTER C. S. , KE Y.
Published: November 2003

The normal prostate is, structurally and functionally, a highly complex glandular tissue in which populations of epithelial and stromal cells interact, one with the other, and are under a constant state of proliferation, differentiation, elimination and selective secondary replenishment so that functional integrity of the tissue is maintained. The ability of normal prostatic tissue to maintain its structure and function is dependent upon retention of cells, generally regarded as ‘stem cells’, which are able to respond by proliferation and selective differentiation within a wide range of phenotypic alternatives. With respect to cells in the epithelial compartment, replenishment is possible at several levels from within distinct pathways of normal cellular differentiation. It is now appreciated that fully differentiated prostatic epithelial cells retain a far greater degree of phenotypic ‘plasticity’ than was earlier apparent from morphological examination of the intact tissue. This inherent plasticity, coupled with the ability of the intact tissue to respond to diverse environmental (particularly humoral) stimuli by regenerating a wide and divergent spectrum of functional prostatic epithelial phenotypes is its strength — but also its weakness. Disturbance and distortion of the homeostatic regulatory mechanisms, whether physical or humoral, which control the normal sequence of epithelial proliferation, differentiation and elimination exposes these cells, particularly multipotent ‘stem cells’, to an increased probability of genetic change, thus resulting in either transient, or permanent, neoplastic transformation.
Characterization of apoptosis in intestinal ischaemia‐reperfusion injury — a light and electron microscopic study.
Authors: SHAH KETAN A. , SHUREY SANDRA , GREEN COLIN J.
Published: November 2003

Intestinal ischaemia‐reperfusion (IR) injury has largely been attributed to cellular necrosis. Apoptosis, a distinct form of cell death has been observed following IR to the brain, heart, adrenals and the kidneys. In order to characterize the role of apoptosis in intestinal IR, small bowel grafts were stored in saline (n = 6) or modified University of Wisconsin solution (n = 6) at 4 °C for 12 h and reperfused for 6 h in syngeneic rats. Samples of normal, stored and reperfused intestines at 1, 3 and 6 h were analysed by light and electron microscopy. Following reperfusion, there was crypt and villous epithelial apoptosis, loss of crypt and villous structures, and an increase in mucosal inflammatory cell infiltration. Ongoing apoptosis was maximum at 1 h, its degree decreasing with increasing reperfusion intervals. Large numbers of apoptotic bodies dominated the picture from 3 h of reperfusion. This study has demonstrated the induction of apoptosis by intestinal IR injury, which begins within an hour of reperfusion and is probably responsible for the observed crypt and villous loss. This has potential therapeutic implications as, opposed to necrosis, apoptosis is an active process with genetic regulators and biochemical effectors, which can be specifically targeted to prevent or alleviate IR injury.
Effect of methylprednisolone on the ulceration, matrix metalloproteinase distribution and eicosanoid production in a model of colitis in the rabbit
Authors: ANTHONY DANIEL , SAVAGE FELICITY , BOULOS PAUL , HEMBRY ROSALIND , SAMS VIRGINIA , TREVETHICK MICHAEL
Published: November 2003

This study has examined the response of a rabbit model of inflammatory bowel disease to methylprednisolone. Colitis was induced in the colon of rabbits with 40 mg trinitrobenzenesulphonic acid in 25% ethanol (TNBS). The effect of methylprednisolone (0.5 mg/kg/day) on the development of colitis was determined at one week, by examining the colon's macroscopic and microscopic appearance, the distribution of matrix metalloproteinases (MMPs) and by measuring eicosanoid production. Although there was no difference in the area of ulcerated colonic tissue in the treated and untreated TNBS animals, the increase in polymorphonuclear leucocytes was significantly reduced in TNBS rabbits given methylprednisolone. The only difference in the distribution of MMPs was a reduction in the number of polymorphonuclear leucocytes containing gelatinase B. The release of immunoreactive PGE2 and LTB4, but not 6‐keto PGF1α, was increased in the TNBS animals and was unchanged by methylprednisolone. These results show that methylprednisolone does not modify the injury produced by TNBS in this model despite reducing the infiltration of polymorphonuclear leucocytes. Hence it suggests that these cells do not contribute to the injury observed, are not the source of the eicosanoids and that gelatinase B is not required in the healing process in this model.
Impaired human coronary artery distensibility by atherosclerotic lesions: a mechanical and histological investigation
Authors: FRØBERT OLE , SCHIØNNING JØRGEN , GREGERSEN HANS , BAANDRUP ULRIK , PETERSEN JENS AAGE KØLSEN , BAGGER JENS PEDER
Published: November 2003

The objective of this study was to evaluate the relationship between human coronary artery distensibility and vessel wall morphology assessed by histomorphometry. Coronary artery pressure‐cross‐sectional area relations and distensibility were studied in excised autopsy hearts by means of a balloon‐based impedance planimetric technique 2 cm from the aortic orifice of the arteries. Later the hearts were perfusion fixed at 100 mm Hg and cross‐sectioned 17, 20 and 23 mm distal to the aortic orifice. The areas of lumen, intima and media were measured. Nineteen left anterior descending coronary arteries (LAD) and 15 right coronary arteries (RCA) from 25 hearts (12 women and 13 men) were investigated. The age of the subjects was 48–97 years (mean 73.8 years). Non‐linear relations were found between balloon pressure and coronary cross‐sectional area (according with the function y = a + bx0.5) and between balloon pressure and coronary distensibility, but there were no differences in these relations between the LAD and RCA. Subjects' age was positively correlated with wall thickness (r = 0.44, P < 0.05), intima area (r = 0.46, P < 0.01) and media area (r = 0.44, P < 0.05) of the coronary arteries. Additionally, the distensibility at low pressures was inversely correlated with arterial wall thickness (r = −0.37, P < 0.05). When focusing only on arteries with concentric atherosclerotic lesions, distensibility at low pressures was inversely correlated with arterial wall thickness (r = −0.57, P = 0.01) and intima area (r = −0.53, P < 0.05). Arteries with concentric lesions were less distensible at low pressures compared with arteries having eccentric lesions (5.4 ± 0.8.10−2vs. 3.6 ± 0.7.10−2 kPa−1, P < 0.05) but this difference was absent at higher pressures. No difference in coronary artery distensibility was found between men and women. Age and distensibility were not correlated. These findings may have in vivo implications for complications to angioplasty procedures such as recoil and restenosis.
Endogenously elicited antibodies to platelet derived growth factor‐BB and platelet cytosolic protein inhibit aortic lesion development in the cholesterol‐fed rabbit
Authors: RUTHERFORD CLAIRE , MARTIN WINSTON , CARRIER MARTIN , ÅNGGÅRD ERIK E. , FERNS GORDON A.A.
Published: November 2003

Several studies have indicated that growth factors, such as platelet derived growth factor (PDGF), may be important in atherogenesis. These factors are released from platelets, or expressed by cells of the arterial wall. In order to study their role in atherogenesis more directly, rabbits were immunized with PDGF‐BB, platelet cytosolic protein, or human serum albumin (HSA), until high titres of antibody were attained. Atherosclerotic lesions were subsequently induced by feeding the animals with a 2% cholesterol enriched diet. At the end of approximately 3 months, the extent of aortic lesion development was assessed by image analysis of en face preparations of aortae stained with Oil Red‐O, and histological segments of aortae taken at the level of the first intercostal artery branch point. The endogenous antibodies were characterized with respect to their cross‐reactivity, and ability to neutralize PDGF and platelet cytosol‐induced cell proliferation and migration in vitro. The endogenous, anti‐PDGF‐BB antibody was isoform specific, and neutralized the mitogenic and chemotactic properties of PDGF‐BB and rabbit platelet cytosolic protein in vitro. The anti‐platelet cytosol antibody partially inhibited the chemotactic and mitogenic properties of rabbit platelet cytosolic protein. Compared to non‐immune rabbits (n=5), animals immunized with HSA (n=4) had a significantly larger area of aortic lesion involvement (P<0.01), whereas aortic lesions in rabbits immunized with PDGF‐BB (n=5), or platelet cytosolic protein (n=7) were significantly smaller than either non‐immune animals, or animals immunized with HSA (P<0.05). The same pattern was observed for other measures of aortic lesion involvement including aortic intima : media ratio at the level of the first intercostal artery. These data suggest that PDGF‐BB, and possibly other platelet‐associated growth factors, are involved in cholesterol‐induced atherosclerosis.
Injury‐induced alterations in newly synthesized sulphated proteoglycans from rabbit arterial neointima covered by regenerated endothelium
Authors: ISMAIL NERMINE A. EHSAN , WASTY FASAHAT , MOORE SEAN , ALAVI MISBAHUDDIN ZAFAR
Published: November 2003

Proteoglycan (PG) synthesis is a highly regulated, dynamic process that is known to be altered during atherogenesis. Endothelial injury, which may be the primary event in atherosclerosis, has been reported to stimulate PG synthesis and accumulation in the arterial extracellular matrix. The objective of this investigation was to study injury‐induced alterations in PG synthesis and accumulation in the neointima, developed in response to a selective balloon catheter de‐endothelialization of aortas of normocholesterolaemic rabbits. One group of rabbit aortas was incubated with 35S‐Na2SO4 for 8 h, to study in vitro the de novo synthesis of sulphated PG. Another group of rabbit aortas was used to study PG accumulated in aortic neointima vs. PG present in intima‐media of normal aortas. Newly synthesized sulphated PG was characterized by light microscopic radioautography and size exclusion chromatography. Purified intimal‐medial PG extracts from unlabelled aortas were analysed for protein and glycosaminoglycan (GAG) content and GAG distribution pattern. Results from this study revealed that the neointima of injured aortas synthesized sulphated PG at a significantly higher concentration than the intima of normal aortas. Size exclusion chromatography revealed that neointima synthesized higher molecular weight PG, and in a higher proportion, than its counterpart PG from normal aortas. PG accumulated in neointima of injured aortas showed a significantly altered GAG distribution pattern. These data confirm that neointima developed in response to injury synthesizes and accumulates PG which is altered compared to PG present in the intima‐media of normal aorta.
Experimental cutaneous leishmaniasis: transmission electron microscopy of the inoculation site
Authors: VASCONCELLOS CIDIA , SOTTO MıRIAN N.
Published: November 2003

Tissue response against inoculation of Leishmania (Leishmania) amazonensis promastigotes in the hind footpad was quite different between two strains of mice: in BALB/c animals there was parasitism of perineurial cells by the 8th week post inoculation (WPI) and heavy parasitism of macrophages, as well as degenerated extracellular parasites close to collagen fibers at the 39th WPI, whereas in C57Bl/6j mice there was heavy parasitism of macrophages at 6th WPI, dermal vessels with high endothelial cell at 21st WPI and well preserved intracellular amastigote forms by 51st WPI. In both animals there was no parasitism of keratinocytes or Langerhans cells. Thus BALB/c mice were useful as an experimental model for diffuse cutaneous leishmaniasis and showing a new feature, parasitism of perineurial cells, whereas C57Bl/6j animals show hypersensitivity signs, together with a few preserved parasites, only late in the course of infection. From a morphological point of view, there were no differences in macrophages, or in the interaction between this target cell and the parasite, between the animal models studied. This suggests that the difference in the response of the hosts towards the parasite could depend on the way in which they activate a cellular, i.e. lymphocyte mediated immune, response.
Nutritional, functional and sensory properties of wheat, rice and fababean blends texturized by drum drying
Authors: Abdel‐Aal El‐Sayed M. , Sosulski Frank W. , Shehata A. Adel Y. , Youssef Mohamed M.
Published: November 2003

Blending of wheat and fababean Flours (73:27 w/w) to the 17.8% protein (N×5.7) level increased the amino acid (AA) score from 38 to 59, whereas a 17.7% protein blend of rice Flour and fababean protein concentrate (82:18 w/w) increased the AA score from 62 to 72. Nutritive indices were not improved by including cottonseed or sesame Flours in the blends. Cooking and texturization on a drum dryer reduced the AA scores to 47 and 67, respectively, for the wheat and rice blends, indicating that rice/fababean blends would be preferred in weaning foods. Texturization caused a marked increase in water absorption but reduced oil emulsiFication of all blends. Sensory evaluation rated the texturized products favourably when consumed as a breakfast cereal or puffed, baked snack.
Effect of heat on microorganisms isolated from freshly caught chilled scad (Trachurus trachurus)
Authors: Vaz‐Pires Paulo , Gibbs Paul , Kirby Roy M.
Published: November 2003

The effects of heat on bacteria making up part of the microFlora of the sea‐Fish Trachurus trachurus were studied. From 80 bacterial isolates which were subject to primary identiFication four were selected. The bacteria were subjected to a heat stress of 55°C for 20 s both in pure and mixed suspensions, the D‐values and post‐stress recovery in nutrient broth were measured. Using differential plating on selective agents to identify sites of injury and recovery times, the growth parameters dissolved oxygen, redox potential and pH were measured during recovery. Bacteria presumptively identiFied as Shewanella putrefaciens and Pseudomonas putida were more sensitive to heat than other bacteria, suggesting that most heat treatments of Fish may reduce the number of these bacteria. After dissolved oxygen was used up during recovery in nutrient broth, Eh declined from positive to negative values typical of facultative bacteria showing that, after initial aerobic growth, the bacteria changed their metabolism to grow anaerobically. When dissolved oxygen reached zero, about 120 h after inoculation, the numbers of all bacteria were about 107mL−1, and corresponds to a minimum in the pH values, except for the most heat sensitive isolate (300 h after inoculation). Differential plating showed increased sensitivity to NaCl induced by heat treatments in some isolates.
Effects of three cellulose gums on the texture profile and sensory properties of low fat frankfurters
Authors: Barbut Shai , Mittal Guari S.
Published: November 2003

Composition, textural, viscoelastic, hydration, colour, and sensory attributes of regular and low fat pork/beef frankfurters with and without cellulose gums (carboxymethyl cellulose (CMC) and two types of microcrystalline cellulose (MCC‐I and II)) were investigated. Fat was replaced with water in the low fat products. Moisture loss during cooking was reduced in low fat products from 10 to 6% because of the addition of CMC; however, both MCC increased moisture loss by 12–15%. CMC addition also increased the amount of free water. The high fat product was lighter (higher ‘L’) than the reduced fat frankfurters; gums did not appreciably change the colour. The viscoelastic properties (relaxation time, elastic moduli) were unaffected by the changes in fat level. Product hardness, brittleness, gumminess and chewiness increased with the decrease in fat level. MCC‐II improved the textural properties of the low fat product to those of the high fat product. Sensory panel results indicated a decrease in tenderness with low fat and this was not improved by MCC‐II. Overall, acceptability scores indicated that all the products (high and low fat) were acceptable.
Total frying‐use time effects on soybean‐oil deterioration and on tortilla chip quality
Authors: Tseng Yi‐Chang , Moreira Rosana , Sun X.
Published: November 2003

Refined soybean oils were degraded at 190°C for 60h to a total polar material of 61.54%. The effect of fresh to highly degraded oil on the physical and thermal properties of the oil as well as on the Final quality of tortilla chips was determined. Surface tension decreased significantly with oil degradation (P < 0.05). Colour readings also changed significantly with oil degradation (P < 0.05) and were more pronounced after 30h of frying. Foam and off‐flavour developed between 20 and 30h of degradation suggesting that the oil should have been discarded when the total polar material reached 27%. The convective heat transfer coefficient changed more rapidly after 30h of frying. The values of the convective heat transfer coefficient correlated highly with viscosity (−0.98). The oils, whether fresh or degraded, behaved as Newtonian fluids. Viscosity was significantly affected by oil degradation time and temperature (P < 0.05). The effect of temperature on the viscosity of the oils was described by an Arrhenius equation. Viscosity changed more rapidly with temperature as the degradation time increased. Tortilla chips were fried in fresh and degraded soybean oils. Total oil content and fracturability of tortilla chips were not affected significantly by oil degradation time (P < 0.05). However, the oil content adhering to the surface of the tortilla chips was significantly higher (P < 0.05) in the tortilla chips fried in degraded oil than in fresh oil.
Rheological behaviour of processed avocado pulp emulsions
Authors: Freitas Suely P. , Da Silva Fernando C. , Lago Regina C. A. , Qassim Raad Y.
Published: November 2003

Shear rate vs. shear stress data were obtained on avocado pulp in water emulsions using a concentric cylinder rheometer and fitted to a power law model. Dilution, as volume fraction of water, had a pronounced effect on the apparent viscosity of the pulp emulsions and the Richardson equation, (ηR= exp.(aϕ) for the emulsion viscosity fitted the data well. A mean slope coefficient, a, of 4.57 can be used as a first approximation. Enzymatic treatment (40°C, 1 h), is slightly more effective than thermal treatment (65°C, 1 h), in reducing the initial apparent viscosity of the pulp‐water emulsions
Influence of CaCl2 and NaCl injections on the texture and flavour of beef
Authors: Rousset‐Akrim Sylvie , Got Florence , Bayle Marie‐Christine , Culioli Joseph
Published: November 2003

The present study compares the effects of pre− and post‐rigor injections of 0.1m CaCl2 or 0.15m NaCl on sensory characteristics (appearance, texture and flavour) and on physical measurements (sarcomere length, drip loss and mechanical resistance of raw myofibres) of beef meat at 2, 6 and 14 days of ageing. An injection of CaCl2 1 h post‐mortem (pH ≈6.8) greatly decreased sarcomere length and myofibrillar resistance, increased drip loss, contracted appearance and brightness, and induced abnormal flavour, mainly bitterness, whatever the ageing time. CaCl2‐treatment 1 h post‐mortem produced little effect on tenderness during ageing; it was slightly higher at day 2 and lower at day 14 than controls. CaCl2‐injection at 24 h post‐mortem did not change the sarcomere length but produced a smaller increase in drip loss and a decrease in the resistance of raw myofibres. Improved meat tenderness compared to controls occurred mainly at days 2 and 6 but, during ageing, abnormal flavour appeared by day 6. NaCl‐injection had no effect on either sarcomere length or resistance of raw myofibres, but produced higher drip loss and saltier taste at day 14 only. Thus pre‐rigor injection of CaCl2 is not recommended because of adverse effects on flavour and appearance of meat. Post‐rigor injection of CaCl2 has a beneficial effect on tenderness in the first part of the ageing period, but after complete ageing, the only overall benefit is a decrease in the variability between animals.
The detection of residual pectin methylesterase activity in pasteurized tomato juices
Authors: Castaldo Domenico , Servillo Luigi , Loiudice Roberto , Balestrieri Ciro , Laratta Bruna , Quagliuolo Lucio , Giovane Alfonso
Published: November 2003

The enzyme pectin methylesterase (PME) is believed to be involved in the destabilization and cloud loss of vegetable juices through the de‐esterification of pectin followed by the successive coprecipitation of the pectate with insoluble materials present in the juices. Cloud destabilization is often observed even when the vegetable products have been subjected to thermal treatment to produce sterile products and also to stabilize the cloud. Therefore it is possible that loss of cloud may be because of residual enzymatic activities surviving the thermal treatments. However, so far no evidence demonstrating the existence of residual PME activity in pasteurized juices has been published. In this paper it is reported that in industrial tomato products showing cloud loss residual PME activity is present. It has been possible to detect this very low activity by an affinity chromatography procedure. The method is based on a cyanogen bromide‐activated resin which is coupled with a pectin methylesterase inhibitor protein purified from kiwi fruit. This resin binds native PME with high selectivity and the enzyme can be concentrated from the product in a single step. Thus, the very low PME residual activity present in pasteurized juice and generally not detectable with common techniques can be detected and easily determined with the method described in this paper.
Assessment of neohesperidine DC stability during pasteurization of juice‐based drinks
Authors: Montijano Helena , D. Coll María , Borrego Francisco
Published: November 2003

The stability of neohesperidine DC during pasteurization of citrus juice‐based soft drinks was investigated in representative (orange, lemon, apple and pineapple) model beverages and under different temperature and acidity conditions. Results showed no significant hydrolysis after 1h at 90°C in the four drinks, or after pasteurization at temperatures ranging from 60°C (4h) to 100°C (45 min). Only at the lowest pH tested (2.0 in a lemon beverage) was a significant loss (8%) of neohesperidine DC detected.
Evaluation of heat‐induced changes in Spanish commercial milk: hydroxymethylfurfural and available lysine content
Authors: Morales Francisco‐J. , Romero Carmen , Jimenez‐Perez Salvio
Published: November 2003

Hydroxymethyfurfural (HMF) content and loss of available lysine were measured as indices of heat damage in various Spanish commercial milks (pasteurized, UHT sterilized and in‐bottle sterilized milks) with similar processing dates. HMF level was determined by the traditional colorimetric procedure and by the reversed‐phase HPLC method. Available lysine was measured by an alternative method with o‐phthaldialdehyde as fluorescent marker. A significative relationship has been found between the HMF content and loss of available lysine and both are suitable for use as heat‐induced indices. When loss of lysine (y) was expressed as percentage and HMF (x) as μm, the function of the correlation line was, y=0.47x−0.089 (r=0.958, P<,0.005).
Elucidation of interactions of lysozyme with whey proteins by Raman spectroscopy
Authors: Howell Nazlin , Li‐Chan Eunice
Published: November 2003

The molecular structure, conformational changes and interactive bonds in bovine whey proteins α‐lactalbumin and β‐lactoglobulin and hen egg lysozyme (15% w/v in D2O pD 6.8) in isolation and in binary combination were examined by Raman spectroscopy. Aggregation was observed in mixtures of lysozyme with either α‐lactalbumin or β‐lactoglobulin (mixed 1:1 weight ratio) which indicated bonds in addition to the reported electrostatic interactions between the oppositely charged proteins (Howell et al., 1995). Both the lysozyme‐α‐lactalbumin and lysozyme‐β‐lactoglobulin complexes showed the involvement of hydrophobic interactions by intensification of spectral bands assigned to CH & CH2 bending vibrations and decrease in the intensity of bands assigned to Trp residues in a nonpolar environment. Changes in the disulphide stretching vibrations of cystine residues as well as lower contents of both helix and sheet structures were also observed. However, the complex with α‐lactalbumin had characteristic changes in its Tyr residues not shown in the complex with β‐lactoglobulin. At 20°C a mixture of α‐lactalbumin and β‐lactoglobulin did not indicate interaction. On heating to 90°C for 30 min gelation of the three proteins and their mixtures was accompanied by changes in the disulphide bonds, in aromatic and aliphatic CH groups involved in hydrophobic interactions, and in secondary structure especially formation of β‐sheet‐like structures. However, interactions of lysozyme with either α‐lactalbumin or β‐lactoglobulin whey proteins resulted in experimental spectra differing from the theoretically calculated average spectra of the component individually heated proteins. In contrast, the overall conformational and structural changes resulting from heating of the α‐lactalbumin or β‐lactoglobulin mixture did not differ greatly from those observed in the individually heated proteins.
Influence of recovery conditions on apparent heat resistance of Bacillus stearothermophilus spores
Authors: López Mercedes , González Isaac , Mazas Margarita , González Josefa , Martin Roberto , Bernardo Ana
Published: November 2003

The effects of post‐treatment environmental factors on the heat resistance of Bacillus stearothermophilus spores (ATCC 12980, 7953, 15951 and 15952) were investigated. Nutrient Agar (NA), Antibiotic Assay Medium (AAM), Dextrose Tryptone Agar (DTA) and Tryptic Soy Agar (TSA) with Ca2+ added to a final concentration of 100 p.p.m. were used as recovery media. No significant differences were seen between D‐values obtained except in the case of strain 12980 when comparing TSA with the other media and for strain 7953 comparing AAM and DTA. The optimum incubation temperature was slightly lower for heated than for unheated spores of each strain, although, in general, 50 °C was adequate. Higher D‐values were obtained at 50–55 °C. The effects of the pH of the medium in the range 5.0–7.0 and the addition of starch and phosphate on heat resistance have also been investigated. Maximum colony counts of heated spores were obtained at pH 7.0 and decreased as pH fell. D‐values were significantly lower at pH ≤ 5.5. Increasing the concentration of phosphate in the recovery medium from 0 to 0.2% resulted in a progressive decrease in spore recovery and D‐values. The addition of starch improved recoverability. The z‐values obtained for the four strains studied under the different recovery conditions were similar with a mean value of 7.58 °C ± 0.28.
Comparative evaluation of the olive oil given by a new processing system
Authors: Ranalli Alfonso , De Mattia Gabriella , Ferrante Maria L.
Published: November 2003

To evaluate the level of quality of the olive oil given by a new processing system we compared it with the percolation oil, which is known to be of high quality. The new product was characterized by the following: (i) higher contents of tocopherols, tyrosol‐ and hydroxytyrosol‐aglycones, volatile aromatic substances, sterols, triterpene alcohols and lipochromes, and higher values of 1,2‐diglycerides/1,3‐diglycerides and campesterol/stigmasterol ratios, colour indices and turbidity; (ii) lower contents of waxes and triterpene dialcohols, and lower values for spectrophotometric indices, carbonyl index, Wolff's ratio (K232/K270), acidity, and peroxide number; (iii) similar contents of phenols, o‐diphenols, free tyrosol, free hydroxytyrosol, triglycerides, stigmastadienes, and aliphatic alcohols, similar sensory score, and similar value of resistance to autoxidation, alcohol index, overall quality indices, and fatty acid composition.
Susceptibility of minimally processed green pepper and cucumber to chilling injury as observed by apparent respiration rate
Authors: Kang Jun Soo , Lee Dong Sun
Published: November 2003

Apparent respiration rate and total microbial count were measured for intact and cut vegetables of green chilli pepper and cucumber stored at 5 and 10 °C. The minimally processed vegetables were more sensitive to chilling injury at 5 °C compared to the intact produce. Their response of increased respiration to chilling injury at 5 °C was noticed earlier than spoilage due to microbial growth, and determined the limit of shelf‐life (4 days) in storage. Due to increased susceptibility to chilling injury when these products were stored at 5 °C, they had shelf‐lives shorter than or equal to those at 10 °C.
Simple rapid processing of African oil bean seeds for ugba production
Authors: Sokari T. G. , Wachukwu C. K.
Published: November 2003

Toasting oil beans in hot (100°C)sand and holding for a further 30 min at 100°C significantly improved dehulling, and the bitter taste was removed by slicing to 1 mm, boiling for 30 min and soaking for 2 h. This simple process achieved the same quality of ugba after fermentation as the much more cumbersome, fuel‐wasting and time‐consuming traditional technique, saving up to 2 days.