摘要:

AbstractBackground: Enigmatically, degradation of debris generated in programmed cell death (apoptosis) elicits little inflammation. Having previously detected the upregulation of lipocortin 1 (LC1), a 35‐kDa protein with anti‐inflammatory and immuno‐suppressive properties, at sites of non‐inflammatory phagocytosis in the central nervous system (J Neurosci Res 36:491–500, 1993), we sought to determine if LC1 was involved in apoptosis.Methods: LC1 immunoreactivity in mammary glands of adult rats was quantified in situ using video microdensitometry before and during postlactational regression.Results: LC1 is present in the mammary ducts but is absent from the alveoli during lactation. One day after weaning, however, LC1 is detected in the lactiferous cells and, as apoptosis proceeds over the ensuing 4 days, total LC1 in the gland increases>10‐fold over resting levels. LC1 remains high in both the apoptotic cells and epithelial phagocytes through day 10, but the total LC1 per gland drops as the apoptotic cells are cleared.Conclusions: Published experiments have shown that LC1 specifically binds Ca++and phosphatidylserine, and that these affinities are modulated by tyrosine phosphorylation and cross‐linking with transglutaminase. Thus, LC1 appears to be a candidate for several putative activities in apoptosis (e.g., phagocyte recognition via phosphatidylserine binding and/or buffering intracellular Ca++) in addition to its anti‐inflammatory role. © 1995

ISSN:0003-276X    

DOI:10.1002/ar.1092420102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractBackground and Methods: RPC C2A cells, cloned from Wistar rat incisor pulp, were grown in culture 2–7 days after exposure to adriamycin at a concentration of 0.1 mg/L for 2 hours. Morphological changes, labelled proline incorporation and alkaline phosphatase activity were studied in response to this treatment.Results: At the light microscopic level, colonies of enlarged cells appeared 2 days after adriamycin treatment. The size of these colonies increased during the course of this study. The control samples showed no apparent changes. At the electron microscopic level, the small cells in the adriamycin‐treated cultures showed fewer vesicles than the controls, but more prominent rough endoplasmic reticulum. However, the enlarged cells contained an abundance of vesicles, and few profiles of rough endoplasmic reticulum. Radiolabelled proline incorporation in the control group was significantly higher than the experimental after 2 days in culture, but showed no significant difference after 7 days. Histological staining for alkaline phosphatase showed that there was a slightly higher intensity in the control samples than in the experimental cultures at this time.Conclusions: This study has shown that the RPC C2A cells will respond to adriamycin treatment in vitro, where the acute effects were quite different from the protracted effects with respect to labelled proline incorporation and alkaline phosphatase activity. © 1995 Wiley‐Lis

ISSN:0003-276X    

DOI:10.1002/ar.1092420103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: SAMP6 was developed as a murine model of age‐related spontaneous osteopenia characterized by low peak bone mass. A morphometric study of the growing femur in SAMP6 and sex‐matched SAMP2 at 10 days to 4 months of age was done to examine the pathogenic process related to osteopenia.Methods: Age‐related changes in cortical bone thickness, femur score, trabecular bone volume, thickness of epiphyseal growth plate, number of osteoclasts, and osteoclast surface were measured with a computerized image analyzer. Osteoclasts were examined cytomorphometrically after TRAP (tartrate resistant acid phosphatase) staining of the femoral sections.Results: Cortical bone thickness and femur score increased significantly with age, while trabecular bone volume decreased significantly. Comparing mean values of cortical bone thickness, femur score and trabecular bone volume, we noted significantly lower mean values in SAMP6 than in SAMP2 mice. These significant inter‐stain differences first became evident in 20–40‐day‐old mice, but there was no significant difference in thickness of the epiphyseal growth plate between the two strains. The mean values of the number of osteoclasts per unit none surface length and of the osteoclast surface in SAMP6 were significantly greater than in age‐ and sex‐matched SAMP2. Histograms of distribution of size of osteoclasts of 40‐day‐old male mice revealed that larger ones were more frequently seen in SAMP6. Furthermore, the ratio of osteoclasts/TRAP positive cells free in the bone marrow cavity was significantly higher in SAMP6 than in SAMP2.Conclusion: Activated bone resorption may play a role in the osteopenia seen in SAMP6.

ISSN:0003-276X    

DOI:10.1002/ar.1092420104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: Chondrocytes in the epiphyseal plate undergo a series of well‐defined stages, each stage containing a morphologically homogeneous cell population. However, biochemical studies show that there are some functionally heterogeneous cell types in the calcifying zone of the chick epiphyseal plate.Methods: We studied the sequence of chondrocytic maturation in the normal chick epiphyseal plate ultrastructurally and histochemically. Chondrocytes in the calcifying zone were of three distinct types, the appearance of each cell type being closely related to the stage of matrix calcification.Results: Clear cells were observed in the upper calcifying region, stellate cells appeared in the middle calcifying region, and hypertrophic clear cells appeared in the lower calcifying region. Rough endoplasmic reticulum (RER) and lysosome‐rich cells were found, these being limited to the outermost layers of the calcifying zone and containing ACPase‐positive products. Osteoclasts were attached to the matrix near the RER and lysosomerich cells in the poorly calcified regions.Conclusion: We hypothesized that each cell type played a different role in the initiation, progression, and maintenance of cartilage calcification. RER and lysosome‐rich cells may be responsible for the resorption of uncalcified cartilage matrix, this resulting in induction of the osteoclastic resorption of the calcified matrix. In addition, the fate of the chondrocytes was twofold: hypertrophic clear cells died, while the RER and lysosme‐rich cells survived, suggesting that these cells were transformed into osteogenic cells. © 1995 Wiley

ISSN:0003-276X    

DOI:10.1002/ar.1092420105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: It is not known whether long bones and calvaria have distinct biological characteristics. Octacalcium phosphate (OCP), which is a precursor phase of the hydroxyapatite, has been reported to stimulate bone formation if implanted in the subperiosteal region of mouse calvaria. The present study was designed to investigate how the long bone and the calvarium respond to OCP implantation and to compare their biological characteristics.Methods: The synthetic OCP was implanted into the subperiosteal region of rat tibiae and parietal bones being mixed with bovine type I collagen treated by pepsin (Atelocollagen). The biological response was examined histologically and immunohistochemically for collagen matrix phenotypes of types I and II to identify bone and cartilage formation.Results: Both chondrogenesis and osteogenesis were initiated in the tibia 1 week after implantation of OCP and most of the cartilage was replaced by bone at week 2. However, the parietal bone did not show osteogenesis responding to OCP implantation until week 3, and no cartilage formation was associated with the osteogenesis.Conclusions: The present study demonstrated the distinct characteristics of biological response to OCP implantation between the long bone and the calvarium in terms of whether or not cartilage formation is involved in the stimulated osteogenesis by OCP, and in terms of timing of the stimulated chondrogenesis and/or osteogenesis, i.e., the parietal bone takes more time to respond to OCP implantation than the tibia. © 1995 Wiley‐Liss, I

ISSN:0003-276X    

DOI:10.1002/ar.1092420106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: The success of kidney transplant surgery and ureteral reconstruction requires the preservation of the ureteral blood supply. Because of its potential vulnerability to surgical trauma during trans plant and reconstructive surgery, the ureteral vasculature merits a full anatomical description.Methods: The microvascular anatomy of the ureter was studied in male New Zealand white rabbits by light microscopy and transmission electron microscopy and scanning electron microscopy of vascular corrosion casts and alkali digested tissue.Results: The rabbit ureter is supplied predominantly by a branch of the renal artery proximally (cranial ureteral artery) and by a branch of the vesicular artery distally (caudal ureteral artery). Minor vascular continuities are also present between the capillary beds of the ureter and those of the renal pelvis cranially and the bladder wall caudally. There are no external vascular connections to the middle ureter with the exception of a single, small vein which drains into the inferior vena cava. A single group of longitudinal arteries and veins runs the full length of the ureter within the adventitia. Branches of these longitudinal vessels pass tangentially through the muscularis to supply a vascular complex within the lamina propria. This complex in turn supports a rich, mucosal capillary plexus located at the junction between the transitional epithelium and the lamina propria. In the fixed ureter the capillary plexus lies in grooves formed by displacement of the basal layers of the overlying transitional epithelium. The capillaries are continuous or fenestrated, are often invested with pericytes, and are distributed uniformly around the entire circumference of the ureter.Conclusions: The ureteral vasculature exhibits several unique features related to its function in urine conduction and its ability to accommodate expansion and contraction. The combination of techniques used provides a clear three‐dimensional view of this vasculature. Our findings also confirm that, because of its limited blood supply, the ureter may be very susceptible to injury during renal transplantation or other abdominal surgery. © 1995 Wiley‐Liss,

ISSN:0003-276X    

DOI:10.1002/ar.1092420107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: The testes of rats treated neonatally with propylthiouracil (PTU) grow to almost twice their normal size. The cause of testicular enlargement has been suggested to be the result of delayed maturation of Sertoli cells, allowing Sertoli cell division to occur beyond the 15th postnatal day, the commonly recognized cutoff date for Sertoli cell divisions. It has been shown that an increased population of Sertoli cells in postnatal development supports increased numbers of germ cells in adult animals. After examining developing rats treated neonatally with PTU, we hypothesized that an approximate 10‐day delay in maturation was occurring and proceeded to test this hypothesis experimentally. Thus the purpose of this report was to determine if a 10‐day delay in maturation could explain the increased numbers of Sertoli cells and increased testis size in PTU‐treated animals.Methods: Both control animals and animals treated neonatally with PTU N = 5/group were sacrificed at 15 and 25 days of age and prepared for electron microscopy.Results: Micrographs show and morphometric ultrastructural analysis of numerous parameters demonstrated at the 95% probability level that Sertoli cells from 25‐day‐old PTU animals are not different in size and most constituents (volume and surface area) from 15‐day‐old control animals and are less mature than 25‐day‐old control animals. Mitosis of Sertoli cells was observed in PTU‐treated animals in 25‐day‐old animals but not in agematched controls. The number of Sertoli cells in 25‐day‐old PTU‐treated animals is significantly increased over age‐matched controls. Micrographs show the presence of immature Sertoli cell nuclei in 25‐day‐old animals receiving PTU as well as increased germ cell degeneration in this group. Sertoli cell tight junction formation is also delayed in PTU‐treated animals as compared with controls.Conclusions: Together, the data show that delayed maturation of Sertoli cells occurs in treated animals that corresponds to a minimum of 10 developmental days. In the immature state, Sertoli cells continue to divide. Data presented herein and published data related to PTU treatment indicate that delayed maturation of the Sertoli cell results in delayed maturation and proliferation of other testicular cell types. From this and from published data, the hypothesis is presented thatthe Sertoli cell is responsible for the overall control of test

ISSN:0003-276X    

DOI:10.1002/ar.1092420108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractBackground:Mdxmutant mice, like patients with Duchenne Muscular Dystrophy (DMD), lack dystrophin, a subsarcolemmal protein, that results in myofiber necrosis. However youngmdxmice, in contrast to DMD children, exhibit a successful muscle regeneration and not an extensive fibrosis.Methods: Oldmdxmice were monitored clinically up to their spontaneous death, and most of their organs were studied histologically to look for differences with those of the wild C57BL/10 mice strain.Results: In oldmdxmice (at least 20 months of age), we report clinical and pathological features of muscular dystrophy, i.e., progressive motor weakness and loss of myofibers replaced by extensive connective tissue, similar to the phenotype of dystrophinopathy observed in DMD patients. Various degrees of dystrophic involvement were observed in cardiac, respiratory, postural, and hindlimb skeletalmdxmuscles and also in smooth muscles of the digestive and urinary tracts. No gross histological abnormalities were found in other tissue than muscular tissue.Conclusions: Late in life,mdxmice develop a muscular dystrophy close to DMD dystrophinopathy. We suggest that the study of the effects of ageing in mdx mice would give clues to better understand the pathophysiology of DMD. © 1995 Wiley‐Liss, I

ISSN:0003-276X    

DOI:10.1002/ar.1092420109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: Pial microvessels' responses to local hyperthermia revealed the development of in vivo spontaneous thrombosis. The cellular and subcellular changes which contribute to such events remained unexplored. Therefore, the effect of regional hyperthermia (43°C) on mouse pial microvessels was studied at the ultrastructural level.Methods: A simple cranial window assembly, including an artificial cerebrospinal fluid delivery and heating system to ensure a precise brain regional temperature, was used. The animal core body temperature was maintained at 37°C. Topical and transvessel bimodal fixation of microvessels was done with a phosphate buffered mixture of glutaraldehyde and paraformaldehyde, followed by a standard electron microscopy procedure.Results: When the pial microvessels of control (37°C) animals were examined, no evidence of cellular damage was discerned. Endothelial. cells including luminal membrane were unchanged. Degranulated platelets or platelet aggregates were not seen. However, numerous platelets in association with scattered red blood cells and occasional white blood cells could be observed in a close proximity, but not adhered, to the endothelial wall of hyperthermic (43°C) brains. Platelets displayed a variety of forms consistent with the onset of platelet activation. Discoid platelets containing granules and spheroid degranulated platelets and those with large pseudopodia were recognized. The venular endothelial surface revealed conspicuous endothelial change, with the presence of endothelial denudation. The site of platelet aggregation in both venules and arterioles was accompanied by focal endothelial lucency and denudation vacuole formation, luminal membrane rupture, and swelling of the nuclear envelope.Conclusions: These findings demonstrate the extent of damage to the pial microvasculature in response to a local hyperthermic exposure. The results emphasize that changes in the endothelium may represent the earliest signs of oncoming vascular pathology. © 1995 Wiley‐Lis

ISSN:0003-276X    

DOI:10.1002/ar.1092420110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: In vertebrates the thymus is primarily regarded as a lymphoid organ whose importance lies in its capacity to produce a large number of lymphocytes that enter the circulation as T cells. In higher vertebrates the organ has also been regarded as a site for my elopoiesis, but this capacity has not been observed in fish. In this study we describe morphologically the presence of intrathymic developing myeloid cells in the sea bass.Methods: The thymus samples were morphologically studied by transmission electron microscopy.Results: We describe the coexistence of cells in different stages of erythropoiesis and granulopoiesis that appear to be developing in situ in some thymus lobes. Degenerated thymocytes and epithelial‐reticular cells occur simultaneously in the same areas.Conclusions: The coexistence of different cellular components of erythropoiesis and the heterophilic series of granulopoiesis with areas of necrosis suggests a relationship between both processes that is influenced by the microenvironment. Our observations also suggest that the presence of intrathymic developing myeloid cells may imply a nonimmunological role for the thymus. © 1995 Wiley‐Liss,

ISSN:0003-276X    

DOI:10.1002/ar.1092420111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY