Role of elastic fiber degradation in emphysema-like lesions of pulmonary lymphangiomyomatosis

To study the pulmonary structural remodeling in pulmonary lymphangiomyomatosis, electron microscopy and light and electron microscopic immunohistochemical observations for elastin and alpha 1-antitrypsin were performed on five open lung biopsy samples. Lung specimens showed emphysema-like changes in areas of abnormally accumulated smooth muscle cells. In the alveolar walls having accumulated smooth muscle cells, elastic fibers were decreased in number, disrupted, granular, and occasionally accumulated. Ultrastructurally, elastic fibers in areas of smooth muscle cell accumulation showed poorly outlined amorphous components and a few microfibrils, and occasionally showed electron-dense granular deposits in and around the amorphous components. Spiraling collagen fibrils were frequently found associated with these abnormal elastic fibers. Immunohistochemistry for elastin showed even staining of amorphous components of elastic fibers in the areas of smooth muscle cell accumulation. alpha 1-Antitrypsin was also detected evenly in amorphous components of elastic fibers in the areas of smooth muscle cell accumulation. It is proposed that the emphysema-like lesions of lymphangiomyomatosis are mediated by the degradation of elastic fibers, and these degraded elastic fibers are related to an imbalance of the elastase/alpha 1-antitrypsin system similar to the probable pathogenesis of emphysema.     

Ultrastructural changes of smooth muscles in varicocele veins

Background: Varicocele is a dilatation of the pampiniform venous plexus and internal spermatic veins. It affects about 15-20% of male population and can cause infertility. Objective: To describe the most significant ultrastructural changes of the smooth muscle cells in grade 3 varicocele veins. Methods: The authors analyzed 2- to 3-cm tracts of pampiniform venous plexus from 20 patients who underwent varicocelectomy for left varicocele. Light microscopic examination was performed with Van Gieson's stain. Ultrastructural examination was done using scanning and transmission electron microscopy. Results: Light microscopic examination revealed irregularity and separation of medial smooth muscle cells by abundant collagen fibers in varicocele veins. On scanning electron microscopy, the medial layer of varicocele veins showed hypertrophy, irregularity, and separation of the outer longitudinal smooth muscle cells and deposition of numerous fatty globules in between muscle fibers. Transmission electron microscopy showed marked indentation and chromatin condensation of the nucleus, presence of clear vacuoles and myelin figures in the cytoplasm and plasmalemmal projections and formation of ghost bodies. Furthermore, smooth muscle cells were found to have pseudopodia-like projections around adjacent elastic and collagen fibers. Conclusions: The degenerative changes observed in smooth muscle cells and presence of abundant collagen fibers in the medial layer may contribute to the development of the varicocele of pampiniform venous plexus. Further molecular studies are required to shed more light for the underlying mechanism.     

Morphometry and histoenzymology of the hamster tenuissimus and its muscle spindles.

Muscle spindles and extrafusal fibers in the tenuissimus muscle of mature golden Syrian hamsters were studied morphologically and quantitatively using several light microscopic techniques. Muscle spindles were identified in serial-transverse frozen-sections of whole muscles stained with hematoxylin and eosin. Five tenuissimus muscles were examined from origin to insertion, and the locations of individual receptors were plotted in camera-lucida reconstructions. Spindles were found in proximity to the main neurovascular bundle in the central core of each muscle. A range of 16-20 receptors was noted per muscle. The mean muscle spindle index (the total number of spindles per gram of muscle weight) was 503 and the average spindle length was 7.5 mm. Oxidative enzyme and myosin adenosine-triphosphatase (ATPase) staining profiles were also evaluated in the intrafusal and extrafusal fibers in each muscle. Even numbers of type I and type IIA extrafusal fibers were distributed homogeneously throughout all muscle cross-sections. Histochemical staining patterns varied along the lengths of the three intrafusal fiber types. Nuclear chain fibers possessed staining properties similar to the type IIA extrafusal fibers and exhibited no regional variations. Bag1 fibers displayed staining variability, particularly when treated for myosin ATPase under acid preincubation conditions. Some spindles were isolated under darkfield illumination and then either treated with 7-nitrobenz-2-oxa-1,3-diazole (NBD)-phallacidin to detect filamentous actin by fluorescence microscopy, or prepared for conventional scanning electron microscopy (SEM). By fluorescence microscopy, a registered actin banding-pattern was observed in the sarcomeres of the intrafusal fibers, and variations in the intensity of banding were noted amongst different fibers. SEM revealed punctate sensory nerve endings that adhered intimately to the surfaces of underlying intrafusal fibers in the equatorial and juxtaequatorial regions. By transmission electron microscopy (TEM) these endings appeared crescent-shaped and were enveloped by external laminae. Each profile contained numerous mitochondria and cytoskeletal organelles. The high spindle density observed in this muscle suggests that the hamster tenuissimus may function in hindlimb proprioception.     

Ultrastructural Changes of Smooth Muscles in Varicocele Veins

Background: Varicocele is a dilatation of the pampiniform venous plexus and internal spermatic veins. It affects about 15–20% of male population and can cause infertility.

Objective: To describe the most significant ultrastructural changes of the smooth muscle cells in grade 3 varicocele veins.

Methods: The authors analyzed 2- to 3-cm tracts of pampiniform venous plexus from 20 patients who underwent varicocelectomy for left varicocele. Light microscopic examination was performed with Van Gieson’s stain. Ultrastructural examination was done using scanning and transmission electron microscopy.

Results: Light microscopic examination revealed irregularity and separation of medial smooth muscle cells by abundant collagen fibers in varicocele veins. On scanning electron microscopy, the medial layer of varicocele veins showed hypertrophy, irregularity, and separation of the outer longitudinal smooth muscle cells and deposition of numerous fatty globules in between muscle fibers. Transmission electron microscopy showed marked indentation and chromatin condensation of the nucleus, presence of clear vacuoles and myelin figures in the cytoplasm and plasmalemmal projections and formation of ghost bodies. Furthermore, smooth muscle cells were found to have pseudopodia-like projections around adjacent elastic and collagen fibers.

Conclusions: The degenerative changes observed in smooth muscle cells and presence of abundant collagen fibers in the medial layer may contribute to the development of the varicocele of pampiniform venous plexus. Further molecular studies are required to shed more light for the underlying mechanism.     

Ultrastructure of intramural coronary arteries in pigs with hypertrophic cardiomyopathy.

Pigs with hypertrophic cardiomyopathy diagnosed by echocardiographic examination were selected for study from a genetic breeding herd. Under dissecting microscopic examination, intramural coronary arteries in the septum and left ventricular free wall of euthanized pigs were collected for ultrastructural study. The major lesions of wall thickening included degeneration or denudation of endothelium, subendothelial edema, proliferation of collagen fiber, and hyperplasia of smooth muscle cells. Smooth muscle cells proliferated and migrated through the internal elastic lamella into the intima, which caused the early lesion of wall thickening of the intramural coronary arteries. The extent of smooth muscle cell proliferation was related to the severity of endothelial damage. The smooth muscle cells in the intima were identified by immunohistochemical staining (i.e., smooth muscle actin [SMA] stain). Three major types of severe wall thickening with narrow lumen were observed in the intramural coronary arteries. Edema in the intima caused the major lesion of Type I wall thickening. The internal elastic lamella was broken into small interrupted fragments, and fine fragments of elastic fibers surrounded by the cellular processes of smooth muscle were observed in Type I lesions. Many smooth muscle cells proliferated in the intima and media, which constituted the major lesion of Type II wall thickening of the intramural coronary arteries. Many vacuolized, degenerated smooth muscle cells with fewer sarcoplasmic myofilaments could be clearly observed in the Type II lesions. In advanced cases, severe vacuolization and degeneration of smooth muscle cells with the presence of many bizarrely shaped smooth muscle cells in the walls of the intramural coronary arteries could be observed, which caused the major lesion of Type III wall thickening. Pigs with hypertrophic cardiomyopathy, characterized by spontaneously occurring lesions in intramural coronary arteries, may prove a valuable animal model for human disease.     

Histochemistry of glutamate metabolizing enzymes in the rat cerebellar cortex

Applying catalytic enzyme histochemistry, glutamate dehydrogenase (GDH) and phosphate activated glutaminase (PAG) were demonstrated at the light microscopic level, and aspartate aminotransferase (AAT) was detected at the electron microscopic level. GDH staining appeared preferentially in glial cells (Bergmann glia and astrocytes), whereas AAT was localized only in neuronal structures. Cytoplasmic AAT was demonstrated in the perikarya and terminal plexus of basket cells, in the perikarya of stellate cells, in about 60% of the granule cells, in mossy fiber boutons, in numerous small boutons in the molecular layer, and in the axoplasm of numerous myelinated and unmyelinated fibers. PAG was observed in both neuronal structures (perikarya of granule and Purkinje cells) and in astrocytes and Bergmann glia.     

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes. Report of an autopsy

We present an autopsy report on a 14-year-old girl with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS), placing emphasis on the mitochondrial enzymatic histochemistry of the 3 types skeletal muscle and cardiomyocytes. Generalized muscular atrophy, cardiac hypertrophy, cerebral cortical laminar necrosis, basal ganglia calcification and liver steatosis were observed. In the skeletal muscles, modified Gomori's trichrome staining demonstrated scattered ragged red fibers, and histochemical staining for mitochondrial enzymes showed intense positivity in the subsarcolemmal zones of some muscle fibers. Some of the hypertrophic cardiomyocytes also showed a ragged red appearance with the modified Gomori's trichrome stain. Histochemical staining for mitochondrial enzymes showed patchy loss of enzymatic activity in the myocardium. Electron microscopically, extreme accumulation of enlarged mitochondria and severe loss of myofibrils was observed in both skeletal muscle fibers and cardiomyocytes. The arteriolar smooth muscle cells also showed a mild increase in mitochondria.     

Morphology and Innervation of the Human Cremaster Muscle in Relation to its Function

The electromyographic properties of the cremaster muscle (CM) are quite different from other skeletal muscles. It shows excessive spontaneous discharges, and the motor unit shape and firing frequency of the CM muscle differ from that of limb muscles. In this study, CM of six adult cadavers and six orchiectomy specimens were used to reveal the detailed histology of the muscle and provide an anatomophysiological explanation for these unusual electromyographic properties. Routine histochemical stains revealed the CM was composed of several distinct bundles of smooth and striated muscle fibers within connective tissue. The smooth muscle fibers that were more profuse than previously known and were not arranged in layers, but widely dispersed between striated muscle fibers. Bielschowsky silver staining technique, anti‐neurofilament and anti‐synaptophysin immunostaining showed the presence of multiple motor end‐plates observed as a series of small dots or lines running along the striated muscle fibers and several nerve endings on a single muscle fiber. Myosin immunostaining confirmed the CM is a slow‐twitch muscle, and α‐actin smooth muscle immunostaining confirmed the presence of a large number of smooth muscle fibers. There were also small multipolar neurons forming nerve plexuses between smooth muscle fibers. Anti‐GFAP immunostaining confirmed the presence of glial cells similar to astrocytes. In conclusion, the findings of this detailed anatomical study showed the CM, widely known as a striated muscle, contains a large number of smooth muscle fibers, and the spontaneous electromyographic discharges are due to the presence of multiple motor end‐plates and dense innervation. Anat Rec,291:790‐796, 2008. © 2008 Wiley‐Liss, Inc.     

2型糖尿病小鼠移植静脉再狭窄的血管平滑肌分布和功能的初步研究

目的 在构建2型糖尿病小鼠下腔静脉移植模型的基础上,观察糖尿病对移植术后桥静脉再狭窄后血管平滑肌的影响.方法 取20只8周龄雄性自发2型糖尿病C57 BL/KsJ leprdb/db(db/db)小鼠和20只C57 BL/KsJ野生型小鼠,建立下腔静脉-颈总动脉旁路移植手术动物模型,通过超声评估移植后血管血流及血管直径...     

实验性哮喘下呼吸道神经激肽B免疫反应纤维

用免疫组织化学方法研究了神经激肽B免疫反应纤维在实验性哮喘豚鼠下呼吸道的变化。在气管和支气管,实验组一抗最佳稀释浓度为1:1500,对照组为1:1000,当两组的一抗浓度均为1:1500时,两者的神经激肽B免疫反应纤维见于平滑肌层,上皮内、上皮和平滑肌交界处以及外膜层,实验组的纤维数量明显多于对照组。在肺组织,实验组一抗最佳稀释浓度为1:2000,对照组为1:1500,当一抗稀释浓度均为1:2000时,两组的神经激肽B免疫反应纤维主要见于肺内各级支气管平滑肌层、血管壁平滑肌层、血管周围结缔组织和肺泡隔内,但实验组的阳性纤维数量明显比对照组多。     

Coexistence of Dense and Sparse Areas in the Longitudinal Smooth Muscle of the Anal Canal: Anatomical and Histological Analyses Inspired by Magnetic Resonance Images

Magnetic resonance images of the anal canal show small, circular, low-intensity areas arranged in a row and a high-intensity area surrounding them internally and externally in the longitudinal muscle layer that cannot be explained by current anatomical findings. The purpose of this study was to elucidate the detailed structure of the longitudinal smooth muscle of the anal canal and to interpret the magnetic resonance image of the longitudinal muscle. Specimens for macroscopic anatomy and histology were obtained from six and seven cadavers, respectively. The histological nature of the longitudinal muscle was examined by staining serial transverse and coronal sections of the lateral wall of the anal canal with Masson's trichrome stain and using immunohistochemistry for smooth and skeletal muscle fibers. Dense and sparse areas of smooth muscle fibers coexisted in the longitudinal muscle layer. The dense areas formed columnar muscle bundles approximately 1.0–1.5 mm in diameter, and they continued from the longitudinal muscle bundles of the rectum. The columnar muscle bundles of the longitudinal anal muscle were internally and externally surrounded by sparsely arranged smooth muscle fibers that ran longitudinally. The coexistence of dense and sparse areas of smooth muscle fibers suggests that the structure of the smooth muscle is optimized for its function. This histological nature is probably reflected in the magnetic resonance image of the longitudinal muscle as the coexistence of low- and high-intensity areas. Clin. Anat. 33:619–626, 2020. © 2019 Wiley Periodicals, Inc.     

Morphometry and histoenzymology of the hamster tenuissimus and its muscle spindles

Muscle spindles and extrafusal fibers in the tenuissimus muscle of mature golden Syrian hamsters were studied morphologically and quantitatively using several light microscopic techniques. Muscle spindles were identified in serial-transvere frozen-sections of whole muscles stained with hematoxylin and eosin. Five tenuissimus muscles were examined from origin to insertion, and the locations of individual receptors were plotted in camera-lucida reconstructions. Spindles were found in proximity to the main neurovascular bundle in the central core of each muscle. A range of 16–20 receptors was noted per muscle. The mean muscle spindle index (the total number of spindles per gram of muscle weight) was 503 and the average spindle length was 7.5 mm. Oxidative enzyme and myosin adenosine-triphosphatase (ATPase) staining profiles were also evaluated in the intrafusal and extrafusal fibers in each muscle. Even numbers of type I and type IIA extrafusal fibers were distributed homogeneously throughout all muscle cross-sections. Histochemical staining patterns varied along the lengths of the three intrafusal fiber types. Nuclear chain fibers possessed staining properties similar to the type IIA extrafusal fibers and exhibited no regional variations. Bag₁ fibers displayed staining variability, particularly when treated for myosin ATPase under acid preincubation conditions. Some spindles were isolated under darkfield illumination and then either treated with 7-nitrobenz-2-oxa-1, 3-diazole (NBD)-phallacidin to detect filamentous actin by fluorescence microscopy, or prepared for conventional scanning electron microscopy (SEM). By fluorescence microscopy, a registered actin banding-pattern was observed in the sarcomeres of the intrafusal fibers, and variations in the intensity of banding were noted amongst different fibers. SEM revealed punctaie sensory nerve endings that adhered intimately to the surfaces of underlying intrafusal fibers in the equatorial and juxtaequatorial regions. By transmission electron microscopy (TEM) these endings appeared crescent-shaped and were enveloped by external laminae. Each profile contained numerous mitochondria and cytoskeletal organelles. The high spindle density observed in this muscle suggests that the hamster tenuissimus may function in hindlimb proprioception.     

Myositis in mice inoculated with Borrelia burgdorferi.

The authors describe the appearance of myositis in immunocompetent and immunodeficient mice after subcutaneous inoculation with Borrelia burgdorferi by histology and immunohistology. Experimental infection of mice 1) causes inflammation of striated but not smooth muscles, 2) affects the entire musculoskeletal system, and 3) is characterized by perivascular and interfacicular infiltration of mononuclear leukocytes in the striated muscle leading to necrosis as well as disruption of muscle fibers. The lesions found in striated muscle specimens were most pronounced in immunodeficient (SCID), less severe in T-cell-deficient nu/nu (BALB/c, C57BL/6) and marginal to moderate or almost not present in immunocompetent AKR/N and C.B-17 mice, respectively.     

Ultrastructural observations of the myenteric plexus of the pylorus in infantile hypertrophic pyloric stenosis.

Myenteric plexuses and smooth muscle of the pylorus obtained by biopsy at pyloro myotomy in 5 infants with hypertrophic pyloric stenosis were studied by electron microscopy. Animal controls consisted of pyloruses from 2 infant and 2 adult rabbits and 2 adult rats. The principal findings in the plexuses of the patients were moderate numbers of variably sized, swollen degenerating axons that contained dense bodies, lamellated figures, vacuoles, granular or fibrillar material, and swollen mitochondria. The significance of this alteration in the etiology and pathogenesis of this disorder is not clear. Neurons in the plexuses showed no definite abnormalities. Although these findings do not confirm previous light microscopic observation of neuronal changes in the pyloric myenteric plexuses, they do not exclude a neurogenic mechanism for this disorder. The presence of small immature neurons and large mature neurons suggests that neuronal maturation and development in infantile hypertrophic pyloric stenosis are not impaired as previously reported. No ultrastructural changes were found in interstitial cells of the myenteric plexuses. Except for hypertrophy of the circular smooth muscle layers, no specific alterations were found in muscle fibers of the pylorus.     

Overview Article: Basal Lamina of Epidermis,Muscle Fibers,Muscle Capillaries,and Renal Tubules: Changes with Aging and in Diabetes Mellitus

Using autopsy material from 14 diabetics and 10 controls (8–84 years old), the authors measured the thickness of basal lamina (BL) in skeletal muscle capillaries, renal tubules, skeletal muscle fibers, and epidermis to determine whether BL accumulation is a generalized phenomenon or limited only to certain anatomic structures. The four structures were selected because earlier experiments in animals have shown that in two (muscle capillaries and renal tubules) BL accumulates as a by-product of cell renewal while in the other two (muscle fibers and epidermis) it does not. In human tissues we found that 1) BL accumulates in muscle capillaries and renal tubules but not in muscle fibers and epidermis, 2) in muscle capillaries and in renal tubules it accumulates in controls and in diabetics as a function of aging, 3) more BL in both anatomic structures accumulates in diabetics than in controls, and 4) the extent of BL accumulation in muscle capillaries and renal tubules does not correlate with duration of diabetes mellitus. In addition to the fact that BL does not accumulate in all anatomic structures in which BL is normally present, the observations indicate that 1) diabetes alone is not responsible for BL accumule tion, 2) diabetes exaggerates age-dependent accumulation of BL, and 3) accumulation of BL in man is probably a by-product of cell renewal.     

Myotonia congenita. A histochemical and ultrastructural study in the goat: comparison with abnormalities found in human myotonia dystrophica.

Muscle biopsy specimens from the myotonic goat, an animal model of heritable myotonia, were examined histochemically and by electron microscopy. After Periodic acid-Schiff (PAS) staining with diastase digestion, there was increased PAS-positive material within myotonic goat fibers, as compared with those of normal goats. Myotonic muscle stained with alizarin red S, a histochemical stain for calcium, also had an increased staining reaction when compared with muscle from normal goats. Several ultrastructural abnormalities were found in myotonic goat muscle using routine osmium and uranyl acetate staining. These included increased density of the t-tubules, electron-dense material within t-tubules, proliferation and dilatation of sarcotubular elements, and abnormal mitochondria in the myotonic biopsy specimens. To further study muscle ultrastructure, ruthenium red and lanthanum were used as electron microscopic stains with specificity for membranes. There was increased density of the sarcolemma and t-tubules in myotonic muscle stained with ruthenium red as compared to normal, and lanthanum produced a darker staining reaction of the myotonic goat sarcolemma. The histochemical and ultrastructural differences between normal and myotonic goat muscle were interpreted to be consistent with a morphologic basis for the abnormal contraction-relaxation properties characteristic of myotonia.     

Histotopographic study of the rectourethralis muscle

Radical perineal prostatectomy, relative to retropubic prostatectomy, has become an increasingly used surgical technique for prostate cancer, following advances in laparoscopic methods for pelvic lymph node dissection. Recent protocols of risk stratification may even obviate the need for lymph node dissection. Section of the rectourethralis muscle (RUM) is necessary for access to the retroprostatic space, however, during this procedure rectal injuries may be produced. In this work, we studied the topography and morphology of the RUM, which, despite its importance in perineal surgery, has not been univocally described in the literature. After in situ formalin fixation, the pelvic viscera were removed from 16 male cadavers (age: 54-72 years) and from 4 full-term infants (gestational age: 37-38 weeks). Serial macrosections of the bladder base, prostate gland, and lower rectum cut in horizontal (6 adults and 2 infants) and sagittal (6 adults and 2 infants) planes underwent histological (hematoxylin and eosin, azan-Mallory, and Weigert's staining) and immunohistochemical (anti-smooth muscle actin and anti-sarcomeric actin) study. The remaining 4 adult specimens were cut in horizontal and sagittal planes and plastinated using the epoxy resin E12 sheet procedure. RUM was identified in 10 of 12 (83%) adult specimens and in 4 of 4 (100%) infant specimens. In both sagittal and transverse sections, it showed a triangular-shaped configuration. In all cases, at the level of its posterior portion, fibers continuing with the longitudinal muscular layer of the rectum were visible. In the majority of adult and infant cases, attachment of muscle fibers into the anterior wall of the anal canal was also observed. Anteriorly, the mean (+/-SD) distance between the RUM and the membranous urethra was 5.3 (+/-1.25) mm in adults and 1.0 (+/-0.41) mm in infants. Location of RUM in the prerectal space and the absence of urethral attachment makes the original name of this muscle, "prerectal," by Henle, more correct. In 7 of 10 (70%) adult cases and in 1 of 4 (25%) infant cases, muscle fibers were densely packed along the lateral portions of the RUM, while in its central portion connective tissue was prevalent, with sparse numbers of smooth muscle fibers. Immunohistochemical staining showed that this muscle consists almost entirely of smooth fibers. In all the infant specimens, the RUM was clearly separated from the levator ani, while in 8 of 10 (80%) adult cases, striated fibers of the levator ani and smooth fibers of the RUM intermingled. These structural associations suggest a functional cooperation between the two muscles, particularly in determining the anorectal flexure.     

Transformation of rabbit arterial smooth muscle cells with Simian virus 40

Summary In vitro studies were carried out to induce viral transformation of vascular smooth muscle cells. Cultured rabbit arterial smooth muscle cells were infected with simian virus 40 (SV 40), and transformed cultures were produced that exhibit altered morphology, increased growth rate and plating efficiency, growth on semi-solid substrate, and chromosomal abnormalities. Nuclear SV 40 T-antigen was detected in all cells of these cultures. Muscle-specific actin was identified by a specific monoclonal antibody suggesting retention of smooth muscle cell characteristics by the transformed cells. Significant cytoplasmic lipid accumulation occurred in transformed cells incubated with -very low density lipoprotein, as revealed both by chemical analyses and Nile Red lipid staining of the cultures. The transformed smooth muscle cells grow permanently in cell culture. Our investigations show that arterial smooth muscle cells transformed with SV 40 virus exhibit altered phenotypic properties distinct from that of normal arterial smooth muscle cells.     

BPD-MA光动力作用诱导兔血管平滑肌细胞凋亡的初步研究

目的：探讨新型光敏剂苯并卟啉衍生物单环酸A（BPD-MA）光动力作用诱导血管平滑肌细胞凋亡及机制。方法：用体外培养的兔血管平滑肌细胞，加浓度0．25mg／ml的光敏剂BPD-MA，经能量密度4．8J／cm^2波长650nm半导体激光照射。免疫组化染色鉴定平滑肌细胞，HE染色观察细胞形态，MTT法测定细胞增殖活性，TUNEL法观察细胞凋亡。结果：在4．8J／cm^2激光能量密度照射下，与空白对照组比较，光动力作用对平滑肌细胞增殖活性有显著地抑制作用（P〈0．01），单纯激光组照射埘平滑肌细胞的增殖则无明显抑制作用（P〉0．05）。BPD-MA光动力作用使光动力组的大多数细胞出现凋亡。结论：凋亡可能是苯并卟啉衍生物单环酸A光动力抑制兔血管平滑肌细胞增殖的关键因素。     

Elastofibroma: a clinicopathologic and immunohistochemical study of seven cases and literature review

Elastofibroma is a rare fibrous lesion characterized by accumulated abnormal elastic fibers whose etiology remains largely unknown. In this study, we analyzed seven cases of elastofibroma to further explore the characteristics of its cellular composition. Immunohistochemistry was performed for mast cell tryptase, S-100 protein, vimentin, CD34, smooth muscle actin, desmin and collagen type IV. Histochemical staining methods for Gomori's trichrome and Verhoeff elastica-van Gieson were also evaluated. Histopathologically, a haphazard array of collagen, eosinophilic amorphous fibers, and globules in a fibrous tissue was seen. The elastic nature of the fibers was confirmed by elastic stain, and with Gomori's trichrome collagen fibers were also demonstrated. The interspersed spindle or stellate cells were almost consistently positive for vimentin and frequently positive for CD34. Mast cell tryptase-positive cells were present in five of the cases. Collagen type IV immunoreactivity was seen in two cases. No staining was observed with smooth muscle actin, desmin or S-100 protein. Our findings suggest that CD34-positive mesenchymal cells are an integral component of elastofibroma.