Melanoacanthoma and related disorders. Simulants of acral-lentiginous (P-P-S-M) melanoma.
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Dendritic Cells↗
Biomedical subjects
W A Anderson
Publications and source records attributed to W A Anderson.
Ependyma of the rat fourth ventricle and central canal: response to injury.
The response of ependyma in the fourth ventricle and central canal to injury was investigated in young Sprague-Dawley rats. Animals received either a small unilateral incision in the lateral funiculus of the thoracolumbar (TL) cord or a puncture wound in the dorsolateral medulla. Control and lesioned rats were killed from 2 to 21 days after operation and the tissue encompassing the lesions was processed for light microscopy and transmission electron microscopy. Randomly selected lesioned and control rats received colchicine (0.2 mg/100 g s.c.) 6 h prior to death at postoperative days 1-4. In controls, the central canal of the TL cord was lined by a single layer of uniformly arranged columnar ependymal cells with large basally located nuclei and apically displaced organelles. Prominent membrane fusions and condensations of filaments were consistent features of the apical region of these cells. Their basal poles abutted directly on the subjacent neuropil and occasionally gave rise to radially directed processes. In rats with TL lesions, the lumen of the central canal was collapsed and lined by an irregularly contoured, multilayered appearing ependyma. Ependymal cells were often radially elongated and possessed filament-filled basal processes. Mitotic rates among ependymal cells of lesioned rats reached a maximum of 3.34% on day 2 compared to 0.21 and 0.28% in intact and sham-operated controls, respectively. Mitotic activity declined progressively thereafter and approached control values by day 4. A similar but less pronounced pattern of proliferative activity was seen distal to the cord lesion, however, little activity was observed within the lining of the fourth ventricle of animals with comparable lesions in the medulla.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Interactions of gonadotropins with corpus luteum membranes. XI. Internalization of 125I-hCG in the rat.
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Animals↗
Skeletal muscle ventricles in circulation. One to eleven weeks' experience.
Skeletal muscle ventricles were constructed from canine latissimus dorsi and connected to the thoracic aorta in six dogs. These ventricles were stimulated to contract synchronously during diastole. The skeletal muscle ventricles were capable of continuous stroke work when placed within the arterial circulation for several weeks. Effective synchronous diastolic counterpulsation was produced. These results demonstrate that diastolic counterpulsators can be constructed from skeletal muscle and in the future may provide a feasible therapeutic alternative for the treatment of end-stage cardiac failure.
Animals↗
Oxygen consumption of chronically stimulated skeletal muscle.
The latissimus dorsi muscles of six dogs were made fatigue resistant by chronic electrical conditioning. Once the muscles were conditioned, oxygen consumption was measured during periods of exercise. The ratio of the tension developed to oxygen consumed during moderate stimulation (300 msec on) for the control and the electrically conditioned muscles was 16.3 +/- 3.5 and 36.5 +/- 6.7 kg-sec/ml oxygen, respectively. During intense stimulation (800 msec on) the ratio was 12.6 +/- 2.1 and 54.2 +/- 8.9 kg-sec/ml oxygen, respectively. Thus the conditioned muscle was able to develop and maintain tension with a considerably reduced oxygen expenditure. The increased efficiency of the conditioned muscle helps to explain its increased resistance to fatigue and the ability of pumping chambers constructed from electrically preconditioned skeletal muscle to perform sustained cardiac type work.
Animals↗
A comparison of the effects of climbing fiber deafferentation in adult and weanling rats.
The climbing fiber input to the cerebellar cortex was destroyed using both electrolytic and chemical (3-acetylpyridine) lesions. The long-term effects of climbing fiber deafferentation on the ansiform lobule of weanling and adult rats were examined at both the light and electron microscopic levels. Image analysis of Golgi-impregnated Purkinje cells indicated a significantly lower number of smooth branches and spiny branchlets following climbing fiber deafferentation of both adult and weanling rats. The results suggest that the lower number of smooth branches and spiny branchlets following climbing fiber deafferentation of the weanling rat is the result of a loss of postnatal growth rather than transneuronal degeneration. Ultrastructural evidence is provided in confirmation of these quantitative findings. Formation of ectopic dendritic spines was found following climbing fiber deafferentation of the weanling rat, but not the adult. It is shown that ectopic spines and the denervated dendritic thorns of these animals were synaptically innervated by the parallel fiber system and basket axons. The formation of ectopic spines on climbing fiber deafferentated Purkinje cells may represent a form of dendritic plasticity. Ultrastructurally, the dendritic arborizations of weanling deafferentated Purkinje cells showed no signs of transneuronal degeneration. However, the primary response to climbing fiber deafferentation in the adult rat was marked transneuronal degeneration of the Purkinje cell dendrites. It is suggested that the inability of the adult Purkinje cell to form ectopic spines and to replace the excitatory postsynaptic potential of the climbing fiber varicosity is directly related to the Purkinje cell's subsequent transneuronal degeneration.
Age Factors↗
Long-term effects of parallel fiber loss in the cerebellar cortex of the adult and weanling rat.
Short- and long-term effects of parallel fiber deafferentation of adult and weanling cerebellar cortex were investigated following parasagittal transections of the lateral cerebellar hemisphere. Short-term electron microscopic examination revealed that parallel fibers undergo rapid electron-dense degeneration within 5 days of axotomy. These axons were the only neuronal elements immediately affected by the lesion. The continued maintenance of Purkinje cell terminal branchlets and stellate cell dendrites is dependent upon the presence of an adequate parallel fiber milieu. Morphological evidence is provided which suggests that Purkinje cell dendritic spines may be phagocytically removed by Bergmann glial cells following parallel fiber loss. Although a marked decrease was reported in the number of spines projecting from terminal branchlets following deafferentation of both adult and weanling rats, these data suggest that some spines are capable of increasing their length. The elongation of these spines may represent a form of dendritic plasticity. No evidence was found to suggest that deafferentated terminal branchlets are receptive to forming heterologous synaptic contacts. The primary response to parallel fiber deafferentation for both the adult and weanling cerebellum therefore appears to be transneuronal degeneration.
Animals↗
Contractile proteins (actin, myosin) and tubulin are revealed within DNA-containing nucleocytoplasm in mature spermatozoa of Libinia emarginata L.
The localization of DNA and the distribution of the cytoskeletal proteins actin, myosin and tubulin in spermatozoa of Libinia emarginata L. were the aims of this study. DAPI, a highly reactive DNA-binding agent, revealed fluorescent staining within nucleocytoplasmic compartments around the acrosome and in the radial processes extending from the central region of the spermatozoa. The sites of DAPI-DNA staining corresponded to the position of the branched chromatin fibers revealed by electron microscopy. Antisera to myosin, actin, and tubulin revealed staining at different nucleocytoplasmic sites and in radial processes of the spermatozoa. Myosin was present at the base of each of three radial extensions, whereas actin appeared throughout the nucleocytoplasmic compartment and in the radial extensions. Actin fluorescence corresponded to the 6 nm thick filaments visualized by electron microscopy forming the core of the radial processes. Although tubulin was observed throughout the cell and within radial processes by immunofluorescence staining, intact microtubules were not revealed by electron microscopy. However, SDS PAGE comparisons between Libinia sperm extracts and dogfish brain showed small amounts of protein that comigrate with alpha and beta tubulin. These results demonstrate the existence of contractile proteins (myosin, actin) and tubulin within the DNA-containing nucleocytoplasmic compartments of Libinia sperm.
Actins↗
Peroxidases induced in rat uterus by estrogen administration. I. Synthesis, secretion and immunofluorescent demonstration of fluid enzymes.
Uterine secretions are of fundamental importance in reproductive processes. Uterine activity is related to the hormonal status of the animal, and peroxidase is a major estrogen-regulated glycoprotein in the uterine fluid. Estrogen-induced peroxidase (EIP) can be separated into several isoelectric variants. SDS-PAGE electrophoresis suggested that EIP has a molecular weight of approximately 70kd. The observed pattern of EIP isoforms appears to result from differential glycosylation of a single protein species because neuraminidase treatment resulted in a gradual shift of EIP to the more basic isoelectric variants prior to abolishing enzymatic activity. Antibody raised against one of the major isoelectric variants of EIP demonstrated uterine epithelial cells by immunofluorescence indicating an epithelial cell localization for the enzyme. Radioactive bands comigrating with major EIP isozymes were detected in uterine fluid by in vivo labeling after estrogen treatment. The results of these studies support the hypothesis that EIP is a major estrogen-regulated secretory protein of the uterine epithelium.
Animals↗
A review of family medicine faculty development fellowship programs, their alumni and recommendations for future programs.
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Faculty, Medical↗
Peroxidases induced in rat uterus by estrogen administration. II. Cytochemical and biochemical heterogeneity.
In estrogen and diethylstilbestrol-treated rats, uterine peroxidases originate from two sources, the infiltrating eosinophils (exogenous) and the uterine tissue itself (endogenous). The study reported here distinguished the exogenous peroxidases by biochemical means and by cytochemistry. Eosinophil peroxidases are confined to the stromal and myometrial regions and appear simultaneously with endogenous peroxidases. At 48 h after estrogen-administration, the clear uterine luminal washings contain five peroxidase isoforms; this increases to 7-15 isozymes by 72 h. Uterine fluid peroxidase isozymes are acidic proteins with pI values ranging from pH 4.0 - 7.2, while the principal eosinophil peroxidase is a basic protein with a pI value ranging from pH 8.0-8.9. Eosinophil peroxidase is electrophoretically demonstrable only in the presence of the cationic detergent cetyltrimethyl ammonium bromide (CTAB) and has a spectrophotometric optimum of pH 4.4. In contrast, uterine fluid peroxidases have a pH optimum of 7.2. and no requirement for CTAB. Uterine tissue peroxidase extracted in the presence of Ca2+, showed a minor electrophoretic peroxidase band in the acidic pH range; however, a CTAB-activated peroxidase similar to the principal eosinophil peroxidase appeared as a basic protein. The data strongly suggest that uterine fluid peroxidases are estrogen-induced peroxidases (EIP) distinct from the eosinophil peroxidases that are largely restricted to the stromal compartment. This conclusion is supported by cytochemical studies that show two eosinophilperoxidases. The one shown by DAB was resistant to cyanide whereas the one shown by PPD/PC was inhibited by cyanide. A uterine tissue peroxidase, which was demonstrated only in stromal cells by the DAB medium, was more sensitive to cyanide than the eosinophil peroxidase shown by DAB.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Blocks to polyspermy in Chaetopterus.
Blocks to polyspermy may act either at the level of the egg plasma membrane to prevent gamete fusion or at the level of egg surface coats to prevent gamete attachment. The present study was undertaken to determine what type(s) of block(s) to polyspermy exist in Chaetopterus. The results showed the existence of both types. A rapid block acts at the plasma membrane level based on independence from detectable changes in the vitelline layer and is dependent on external sodium ions. A vitelline layer block had been predicted on morphological evidence and is supported here by demonstrating an increase in polyspermy following chemical disruption of the vitelline layer. However, the vitelline layer of the fertilized egg retained its ability to initiate the acrosome reaction in sperm and attach sperm which had undergone the acrosome reaction. The vitelline layer block resulted from the retraction of egg microvilli from the vitelline layer, and not from elevation of the vitelline layer per se. Thus the vitelline layer of the fertilized egg could be involved in preventing sperm penetration into the egg without being altered structurally or functionally.
Animals↗
Purkinje cell growth beyond the twenty-third postnatal day.
Purkinje cell dendritic trees from adult and weanling cerebella were analyzed with an image analysis system following Golgi-Cox impregnation. Measurements of the mean length, number and total length of primary trunks, smooth branches and spiny branchlets were taken to assess the amount of growth between postnatal days 23 and 150. These results revealed a significant post-weanling growth in the length and number of smooth branches and spiny branchlets.
Animals↗
Nephrotoxic effects of oxygen transport media in the isolated rat kidney.
Perfusion of isolated kidneys from rats demonstrated the following nephrotoxic effects of Fluosol-DA: decreased glomerular filtration rate (GFR), urine flow rate (UFR), and fractional reabsorption of potassium (FrK+) (P less than 0.01). Fluosol-DA perfusions were at flow rates about equal to the physiologically normal rodent renal plasma flow rate of 4 ml/min. Stroma-free hemoglobin (SFH) perfusions, also at 4 ml/min, were associated with physiologically normal renal functions, as were those of control Krebs-Ringer bicarbonate (KRB) perfusions at 32 ml/min.
Animals↗
A reevaluation of midbrain and diencephalic projections to the inferior olive in rat with particular reference to the rubro-olivary pathway.
Projections from the midbrain and caudal diencephalon to the inferior olivary nucleus (ION) in the rat were investigated by using anterograde and retrograde tracing techniques. Particular attention was directed to studying the projection from the red nucleus (RN) to the ION. Tritiated leucine was stereotaxically injected into the RN in six animals. The injection sites and the portion of the medulla containing the ION were processed for autoradiography. In three cases, the injections were largely confined to the RN. In these instances, no terminal labeling was noted in the ION. In the other three animals, the injections spread beyond the RN to include, in one or another of the rats, such areas as the mesencephalic reticular formation (MRF) between the RN and the periaqueductal gray (PAG), the region around the fasciculus retroflexus (FR), the prerubral area, the MRF dorsolateral to the RN, or the region dorsal to the medial geniculate body. In these animals, terminal labeling was observed ipsilaterally in the ION, chiefly in the caudal one-half of the medial accessory olive and in the dorsal lamella and lateral bend of the principal olive. Retrograde transport of lectin-conjugated horseradish peroxidase (WGA-HRP) or the fluorescent dye fast blue (FB), injected into the ION, was used to localize regions in the midbrain and caudal diencephalon containing neurons which project to the inferior olive. Following WGA-HRP injections into the ION, retrogradely labeled neurons were found in the ipsilateral ventral PAG, the MRF between the PAG and the RN, the MRF dorsolateral to the RN, and the area dorsal to the medial geniculate body. Large numbers of heavily labeled neurons were found in the area surrounding the FR. No labeled cells were noted in the RN or the nucleus of Darkschewitsch (ND). Subsequent to FB injections into the ION, fluorescent neurons were observed in the same regions which contained HRP-labeled neurons in the experiments using the enzyme as a tracer. Additionally, very small numbers of FB-labeled neurons were found in the RN and the ND. These results indicate that, in the rat, descending input from the midbrain and caudal diencephalon to the ION arises chiefly from a medially located column of neurons extending from the level of the rostral RN to the region of the FR. Little, if any, input to the ION is derived from the ND or RN in this species, unlike the cat, in which a substantial projection to the ION arises from the ND and the RN.
Amidines↗
Time course of mossy fiber degeneration following pontine ablation in the rat.
The normal ultrastructure of mossy fiber terminals within the ansiform lobule of the rat was investigated in parasagittal sections of the cerebellar cortex. Four types of mossy fiber varicosities (simple and complex dispersed, simple and complex clustered) were distinguished on the basis of the presence or absence of clublike excrescences and the concentration of synaptic vesicles within the cortical zone of the terminal. Removal of the pontocerebellar input to the contralateral cerebellar hemisphere was performed electrolytically. Such lesions, when placed in the basilar pontine gray using a dorsal approach, resulted in the degeneration of nearly the entire population of mossy fiber varicosities within the contralateral ansiform lobule. As early as 3 days following pontine ablation, degenerative changes were observed within the synaptic portions of the mossy fibers. Two distinct axonal reactions were apparent within this population of degenerating varicosities. A small population of mossy fiber varicosities (12%) of the simple clustered variety underwent a rapid course of electron-dense degeneration, which was complete by the fifth day. These mossy fiber varicosities were very susceptible to phagocytosis by reactive glial elements. The second group which consisted of simple (60%) and complex (26%) varieties of dispersed terminals, underwent a very slow course of electron-dense degeneration. Reactive glial cells were rarely found in association with this second group of degenerating varicosities. As a result, most glomeruli were found to contain debris from degenerating mossy fiber varicosities throughout the first 57 days following pontine lesions. The majority of the cerebellar glomeruli, however, were denervated by 80 days.
Afferent Pathways↗
Long-term effect of mossy fiber degeneration in the rat.
Mossy fiber-deafferentated rats (20) were permitted to survive from 34 to to 120 days and subsequently examined following Golgi-Cox preparation or after processing for electron microscopy. The primary response to mossy fiber deafferentation was transneuronal degeneration of the granule cell system. Morphological evidence is provided that suggests that the mossy fiber varicosity plays an important role in the fragmentation and removal of the granule cell digitiform dendrite. Computer-assisted image analysis of Golgi-impregnated Purkinje cells indicated significant losses in both smooth branch and spiny branchlet numbers following loss of the mossy fiber input. Ultrastructural examination revealed that a secondary transneuronal degeneration occurred within the dendritic arborization of both Purkinje cells and molecular layer interneurons. Although an overall reduction in the number of dendritic spines occurred along the terminal branchlets following mossy fiber deafferentation, several of the existing spines underwent marked changes in length, with some elongating to more than twice their size. By increasing the length of their spines, denervated Purkinje cells may acquire new synaptic contacts.
Afferent Pathways↗
Keratosis punctata and atopy. Report of 31 cases with a prospective study of prevalence.
We report 31 cases of keratosis punctata palmaris et plantaris in blacks. Eleven of these were found in a prospective study of 573 consecutive black private dermatologic outpatients, a prevalence of 1.9%, and 20 cases were randomly encountered over a three-year period in the same office. Five of the 30 patients able to give a history were symptomatic, and they and ten others came to the office because of this disease, where as 15 came for other reasons, two of whom were unaware of the disease. Four of the 31 patients also had foot lesions. Four patients were aware of relatives with palmar keratoses. The mean duration of disease was 4.3 years, the median was three years, and the range was zero to 38 years. The mean age at onset was 30.3 years, the median was 29 years, and the range was 12 to 70 years, with one case beginning in infancy. Each patient in the prospective study was examined for personal atopy or for a family history of atopy. Nine (82%) of the 11 patients with keratosis punctata had atopy and/or a family history of atopy. Statistical analysis confirmed the association between keratosis punctata and atopy in the prospective study.
Adolescent↗