Reserpine: effect on structure of heart muscle

We examined the ultrastructure of hearts from dogs given reserpine intramuscularly for 4 days, and from untreated dogs. Sections of the myocardium from treated dogs invariably revealed mitochondrial abnormalities at the 5th and 14th days. These included fragmentation and loss of structure of the cristae, and cyst formation. The appearance at 25 days in the treated as well as in all the untreated dogs was normal. We concluded that reserpine in the dose used produces marked structural changes in the mitochondria of heart muscle, and that these changes are reversible. These changes may account for the myocardial depression sometimes seen after administration of reserpine.

Artificial reproductive technologies in Australia--legislation for the new millennium?

In Australia there have been 26,818 live births after IVF and other assisted conception treatments up to 1997. The 3,164 births resulting from assisted conception in 1996 accounted for 1.2% of all Australian births in that year. In 1997 the number of births had increased by 9.3% to 3,458. Medical and scientific advances in the area of artificial reproductive technology have resulted in a complexity of moral, medical and legal issues with respect to the infertile couple or person. The following paper attempts to highlight some of these issues, from a social, legal and technological perspective, and then consider the approach taken by governments and regulatory bodies.

Contribution of O4+ oligodendrocyte precursors and astrocytes to the glial ensheathment of vessels in the rabbit myelinated streak

The barrier properties and glial ensheathment of blood vessels in the retinal myelinated streak of adult New Zealand White rabbits were characterized at the ultrastructural level by intravascular injection of horseradish peroxidase (HRP) and immuno-electron microscopy with monoclonal antibody O4 and antibodies to glial fibrillary acidic protein (GFAP). Vessels within the myelinated streak did not leak HRP, and they exhibited tight junctions between adjacent endothelial cells. However, unlike their adult counterparts, the retinal blood vessels at postnatal day 18 exhibited substantial endocytotic activity. Both GFAP+ astrocytes and O4+ cells were evident surrounding the preretinal blood vessels of the myelinated streak. Furthermore, O4+ cells exhibited features indicative of high synthetic activity, including a large proportion of extended chromatin and prominent nucleoli within the nucleus, as well as a well-developed Golgi apparatus and numerous mitochondria in the cytoplasm. O4+ cells also exhibited variable quantities of heterochromatin, indicative of early stages of cellular differentiation. These observations are consistent with previous data showing that O4+ cells in the myelinated streak include oligodendrocyte precursor cells, pre-oligodendrocytes, and immature oligodendrocytes (Morcos Y, Chan-Ling T. Glia 21:163-182, 1997). The present data indicate that the preretinal vessels of the myelinated streak possess barrier properties typical of microvasculature in the central nervous system, and that both O4+ cells and astrocytes contribute to the glial ensheathment of these vessels. These vessels thus differ markedly from the leaky preretinal vessels associated with pathological conditions such as retinopathy of prematurity.

Alterations in distribution of actin binding proteins in uterine stromal cells during decidualization in the rat

Immunohistochemistry was used to investigate the involvement of the actin-associated binding proteins, tropomyosin, alpha-actinin and gelsolin with the formation of the decidual cell reaction during early pregnancy in the rat. Tropomyosin was present in the uterine myometrium, but absent from the both decidual and non-decidual stromal cells. alpha-Actinin was absent from non-decidual stromal cells, but present in decidual cells. Gelsolin was present in non-decidual cells close to the uterine stroma as well as in transformed decidual cells. Both gelsolin and alpha-actinin were concentrated around the periphery of the cell. It is proposed that these actin-binding proteins may be involved with the cellular transformations associated with decidualization.

Actin-binding proteins undergo major alterations during the plasma membrane transformation in uterine epithelial cells

BACKGROUND

The apical surface of uterine epithelial cells undergoes a dramatic transformation during early pregnancy. Previous studies have shown that cytoskeletal actin microfilaments are associated with this transformation, but little is known of the role played by actin-binding proteins or which of the many described in other cell types are present in uterine epithelial cells.

METHODS

Immunohistochemical staining using monoclonal antibodies raised against four different actin-binding proteins (alpha-actinin, tropomyosin, gelsolin, and vinculin) was used to study the changing distribution of these proteins in uterine epithelium during early pregnancy in the rat.

RESULTS

Findings indicated the presence of all four of the actin-binding proteins in the uterine epithelium. The distribution of tropomyosin remained unchanged over the period of early pregnancy. Gelsolin and alpha-actinin displayed similarity in distribution. Day 1 showed an apicobasal localisation of reaction product, which by day 6 of pregnancy had concentrated into a thick band across the luminal surface of the cells. Vinculin staining was a diffuse band at the level of the basal plasma membrane at day 1 and became a diffuse faint band across the apical part of the cells on day 6.

CONCLUSIONS

This study confirms the presence of actin-binding proteins in uterine epithelial cells, and these findings are discussed in light of known ultrastructural alterations in the uterine epithelium during early pregnancy. Elucidation of the role of the actin-based cytoskeleton in the uterine epithelium may further our understanding of the dynamics of this unique environment that allows the implantation of a blastocyst.

Effects of combined clomiphene citrate and exogenous oestrogen or progesterone on the vaginal epithelium of ovariectomised rats

The interactive effects of clomiphene citrate (CC) and exogenous oestrogen (E2) or progesterone (P4), on the vaginal epithelium of ovariectomised rats were examined using scanning electron microscopy and light microscopy. Results were compared with P4E2 treatment. Statistical analysis showed no significant difference between the two combination CC treatments. All treatment groups had the ability to stimulate a dormant epithelium and cause surface modifications in the form of individually elongated microvilli and rosette formations. The results of this study indicate that while P4 enhances the oestrogenicity of CC, there is no cumulative oestrogenic effect when E2 and CC are combined, but there is modification of cell surface organisation and evidence of anti-oestrogenic activity.

Morphometric analysis of the muscle fibres of the soleus muscle of the ageing rat: long-term effect of hypophysectomy and food restriction

This communication reports on the effects of ageing, hypophysectomy and food restriction on the fibre sizes of the soleus muscle which is primarily concerned with posture. The results reported here are compared with those previously shown for the gastrocnemius muscle which is involved mainly with locomotion. Muscle fibre size (measured as equivalent circle diameter) in the soleus muscle of the male Wistar rat increased from youth at 130 days (type 1 fibres, 61.2 microns; type 2, 58.3 microns) to middle age at 600 days (type 1 fibres, 70.4 microns; type 2, 68.0 microns) and then underwent atrophy in old age to 1,000 days (type 1 fibres, 54.5 microns; type 2, 38.0 microns). There was no growth or atrophy of these fibres in either hypophysectomized or food-restricted rats. There was an increased range of fibre sizes in control rats between youth and old age being 5-fold for type 1 fibres and 3-fold for type 2 fibres, but there was a loss of type 2 fibres in hypophysectomized rats. This ageing process in the range of fibre size was retarded by hypophysectomy (2-fold increase for type 1 fibres) and to a lesser extent by food restriction (3-fold increase for type 1 fibres). Muscle fibre atrophy and compensatory hypertrophy were not as prominent in the hypophysectomized and food-restricted groups as in the old control groups. In general these effects were similar to those previously shown for the gastrocnemius muscle. However, atrophy of both type 1 and type 2 fibres in old age was more pronounced in the soleus muscle. The retarded ageing of the soleus muscle in hypophysectomized and food-restricted rats was probably due to the absence or reduced circulating levels of hormones known to target muscle cells, such as growth hormone and thyroxine.

Effects of clomiphene citrate on vaginal epithelium of ovariectomised rats

Scanning electron microscopy and light microscopy have been used to study changes to the vaginal epithelium induced by exogenous hormones and clomiphene citrate (CC) administered to ovariectomised rats. Oestrogen (E2) administration resulted in epithelial cell proliferation and keratinisation. The administration of the E2/anti-E2 CC also resulted in the stimulation of cell proliferation, but not to the extent produced by E2. Lack of keratinisation, a decreased number of epithelial layers and decreased epithelial height were viewed as non-oestrogenic, or retarded oestrogenic, effects of CC. Modifications to the surface of vaginal luminal cells were also apparent following CC treatment. Cell apices were raised and separated by prominent borders; the surface covering consisted of short bulb-tipped microvilli that clumped together to form rosettes. Individual, elongated microvilli were also evident. The results of this study indicate that CC has retarded oestrogenic actions, as well as a unique ability to alter cell and surface morphology to produce characteristics dissimilar to those seen after treatment with E2 and progesterone.

Effects of anabolic steroids and high intensity exercise on rat skeletal muscle fibres and capillarization. A morphometric study

The effects were investigated of high intensity short duration exercise and anabolic steroid treatment on the medial gastrocnemius muscle of female rats. Twelve rats were divided equally into four groups, exercise with and without steroid administration and sedentary with and without steroid administration. Animals were made to swim for 5 weeks, 6 days.week-1. Muscle fibres were classified as slow-twitch (ST), fast-twitch oxidative glycolytic (FOG) and fast-twitch glycolytic (FG). Muscle fibre size was measured as the equivalent circle diameter. Exercise (P less than 0.001) and steroid (P less than 0.05) treatments alone, significantly elevated FOG and decreased FG fibre proportions. Overall proportions of fast-twitch and ST muscle fibres did not vary with any of the treatments. Significant differences in the proportion of muscle fibres were found to exist between different areas within the gastrocnemius muscle (P less than 0.05). Exercise and steroid treatments alone did not alter muscle fibre diameters. Combined exercise and steroid treatments did significantly increase ST fibre diameters (P less than 0.05). Exercise only treatment resulted in significant increases in the number of capillaries surrounding ST fibre (P less than 0.05) and FOG fibre (P less than 0.01) types. In conclusion the main finding of this study indicated that anabolic steroids in conjunction with high intensity swimming instigated ST fibre hypertrophy. Exercise and steroid only treatments significantly elevated FOG fibre proportions while FG fibre proportions diminished. Exercise only treatment resulted in significant increases in the number of capillaries surrounding both ST and FOG fibre types.

Clomiphene citrate alters vaginal surface morphology in cycling rats

Cycling virgin female rats were treated with clomiphene citrate (CC) during dioestrus of the reproductive cycle. Animals were sacrificed 2 days after the initial injection and their vaginal tissue was examined by scanning electron microscopy. Animals treated with one dose of CC had an epithelium consistent with a prolonged dioestrus. Treatment with CC for 2 days induced changes in the epithelium that had no resemblance to any normal hormonally controlled event in the vagina. It was found that CC had effects consistent with progesterone alone as well as effects unique to this superovulatory drug.

Morphometrical analysis of skeletal muscle fibre ageing and the effect of hypophysectomy and food restriction in the rat

Morphometrical analyses were carried out on muscle fibres from cross-sectional areas of the medial head of gastrocnemius muscles from 5 groups each of 4 male Wistar rats representing young (aged approximately 100 days), medium-aged (400 days), old (1,000 days), old hypophysectomized (1,000 days) and old food-restricted (1,000 days) rats. Approximately 18,000 muscle fibres were measured in each group. Rats were hypophysectomized when young at 60-70 days and food restriction began at the same age. The results show that there is a reduction in type 2 fibre size (measured as the mean equivalent circle diameter) from 59.7 micron in medium-aged controls to 50.3 micron in old controls, but there is no significant difference between the sizes of type 2 fibres in controls, hypophysectomized or food-restricted rats in old age. Analysis of type 1 fibres demonstrated no differences between young, medium-aged and old controls and the old food-restricted group, but type 1 fibres in the old hypophysectomized group (45.5 micron) were significantly smaller than in the old controls (54.6 micron) and old food-restricted rats (58.5 micron). In old controls there is a 4-fold increase in the range of fibre sizes (coefficient of variation) for type 1 fibres and a 2-fold increase for type 2 fibres, indicating fibre atrophy and hypertrophy. Long-term hypophysectomy is more effective than food restriction in preserving the smaller range of the coefficient of variation of fibre size seen in young controls.

Morphometric analysis of frozen transverse sections of human skeletal muscle taken post-mortem

Necropsies were obtained from 5 muscles from 5 young women. The muscles subjected to morphometrical analysis were the deltoid, brachial biceps, vastus lateralis, gastrocnemius and soleus. Results of measurements taken indicate significant differences in fibre sizes and fibre type composition in analogous muscles between individuals and between different muscles within individuals. Differences were also encountered in muscle fibre size during rigor mortis for up to 48 h after death. Our results suggest that the fibre size variability between individuals determined from necropsy samples will contain a component of induced variation not found in muscle biopsies.

Morphology and morphometry of the rabbit uterus during pseudopregnancy

Morphometry was carried out on the luminal epithelium of the rabbit uterus from oestrus to day 21 of pseudopregnancy. This indicated that syncytia increased in size until day 18, after which a rapid reduction occurred with approximate oestrous dimensions being restored on day 21. Involution of syncytia took place in two overlapping stages with reduction in nuclear numbers occurring from day 12 onwards, followed by loss of cytoplasm mainly after day 18. Ciliated cells predominated at oestrus and day 21 but were sparse at other times. When ciliated cells were plentiful, they were concentrated on the tops of the mucosal folds.

Structure of the uterine luminal epithelium of the brush-tailed possum (Trichosurus vulpecula)

Morphology and morphometry of the luminal surface of the uterus of the brush-tailed possum were studied during the oestrous cycle, in anoestrous animals and after ovariectomy. At oestrus the secretory cells were small and the epithelium heavily ciliated. The relative surface area occupied by secretory cells reached a maximum on Day 13 when plasma progesterone concentrations are maximal. The mean apical surface area of the secretory cells also reached a maximum at this time. Both these measures decreased on Day 18 when involution of the epithelium was taking place. This process was essentially complete by Day 24 and was followed by extensive ciliogenesis. Secretory cells from anoestrous animals appeared to have an apical surface area similar to the minimum recorded during the oestrous cycle and extensive loss of cilia did not occur. Ovariectomy caused loss of ciliated cells and a reduction in the mean apical surface area to a dimension much smaller than that measured in intact animals.

Skeletal muscle aging in the hind limb of the old male Wistar rat: inhibitory effect of hypophysectomy and food restriction

By age 1 100 days (37 mth) hind leg paralysis was found in 50% of ad libitum fed (control) male Wistar rats, but only 10% of food restricted rats and no hypophysectomized rats of that age had this disease. Gastrocnemius muscle weight declined at a faster rate than whole body weight in old ad libitum fed rats but not in old hypophysectomized or food restricted rats. Light microscopic and ultrastructural changes were studied in the muscles of the hind limbs of 11 control, 5 food-restricted and 5 hypophysectomized rats aged 805 to 1 307 days. Light microscopic changes in muscles involved progressive degeneration demonstrated by the accumulation of adipocytes and degenerative inclusion bodies. The main ultrastructural changes were associated with myofibrillar breakdown. In addition there was thickening of the basal lamina around blood capillaries. However, muscle from hypophysectomized and food restricted rats of the same age range as controls possessed normal morphology with reduced thickening of the capillary basal lamina.

Structure of the oviducal epithelium of the brush-tailed possum (Trichosurus vulpecula)

Observations were made using scanning and transmission electron microscopy and were correlated with measurements of the mean surface area and the percentage area occupied by secretory cells to provide precise interpretation of the morphological data. In cyclic and anoestrous possums the oviducts were lined with elaborate folds of mucosa except in the portion of the isthmus adjacent to the uterus where the pattern was much simplified. The folds decreased in height and number after ovariectomy. Secretion was maximal between oestrus and Day 2 of the cycle when most ovulations take place. Extrusion of vesicles was observed in the ampulla and isthmus at this stage although the process was localized to some extent because groups of cells with actively extruding vesicles were interspersed with others which contained vesicles but otherwise appeared inactive. This is interpreted as a device whereby a constant supply of secretion can be maintained over several days. Secretory activity declined between Days 3 and 8 and the epithelium in mid-cycle (Days 8-18) appeared relatively quiescent. By Day 24 there was morphological and morphometric evidence of a return to oestrous conditions, although vesicles had not yet reappeared in secretory cells. Ciliogenesis was prevalent at this time and is probably related to the ovum transport that will occur several days later.

Problems associated with the morphometric measurement of transverse skeletal muscle fibers: I. Analysis of frozen sections

The aim of this study was to evaluate the effects of a number of reported procedures which precede freezing on the cross sectional area of skeletal muscle fibers. Probable sources of variation were recognised as: Within blocks, same animal, same procedure. Variability in the size of muscle fibers from area-based measurements was determined for the anterior head of the biceps femoris muscle of the rat. Fibers were measured within areas selected at random from sections taken from the same block of tissue. Variance within and between sections was subsequently established. Between blocks from rats having undergone the same procedure. Variability in the size of muscle fibers measured within areas selected at random from sections taken from different blocks of tissue within the same animal. Between rats, same or equivalent procedure. Fibers were measured from randomly selected areas within sections taken from blocks of tissue derived from different animals. The muscles were subjected to the same or equivalent treatment prior to freezing. Between procedures. Restraining muscles prior to and during freezing did not significantly affect the results except the procedure involving holding the muscle between two pairs of forceps. However, the variability was high within and between sections and blocks from the same muscle. It is postulated that the variability is of technical rather than biological origin and may be the result of small focal contractions which occur along the fibers during freezing.

Crystalloid inclusions in the Sertoli cell of the koala, Phascolarctos cinereus (Marsupialia)

Crystalloid inclusions are a common feature in the basal region of Sertoli cells in the koala, Phascolarctos cinereus. Generally located near the nucleus, they are non membrane-bounded, slender rectangular structures composed to tubules which are orientated at right angles to the long axis of the crystalloid and regularly arranged in rows parallel to this long axis. The tubules in adjacent rows are offset from one another at definite angles and extensively interconnected by filaments. Neither the composition nor function of the crystalloids has been determined, but their association with tonofilaments and the presence of ribosomes in the vicinity suggests that they are most likely proteinaceous.

Ultrastructural changes in spermatozoa of the brush-tailed possum, Trichosurus vulpecula (Marsupialia), during epididymal transit. Part II: The acrosome

The acrosome in spermatozoa from the caput epididymidis of the Australian Brush-tailed possum, Trichosurus vulpecula, typically forms a cup-like structure, sitting on the anterior third of the dorsal surface of the nucleus. The base of the acrosomal 'cup' is narrowly separated from the nuclear surface, while the body of the 'cup' projects voluminously away from the nucleus. During epididymal transit these pronounced marginal extensions of the acrosome are retracted towards the nucleus, and the electron dense acrosomal material undergoes a process of compaction within the plasma membrane of the head to produce the convex ovate form of the definitive acrosome. During this process a variety of bizarre forms of the acrosome are produced before its final configuration is attained.

Spermiogenesis in the brush-tailed possum, Trichosurus vulpecula (Marsupialia). The development of the acrosome

Acrosome development in the Australian Brush-tailed possum, Trichosurus vulpecula, displays a number of extraordinary features. This is particularly evident in the later stages of spermiogenesis, when the area of the nuclear surface bounded by the nuclear ring, and covered by the acrosome, is reduced considerable. As a result, the acrosomal material becomes located over its definitive position on the anterior third of the dorsal nuclear surface; in this process it is thrown into a series of folds, and a wide subacrosomal space is formed. Further changes around the time of spermiation result in the release of a spermatozoon in which a thin layer of acrosomal material is closely applied to the nucleus over the area of the definitive location of the acrosome, whilst its margins are greatly extended and project freely away from the nucleus. The latter feature does not appear to have been reported for the sperm of other mammals.

Ultrastructural changes in spermatozoa of the brush-tailed possum, Trichosurus vulpecula (Marsupialia), during epididymal transit. Part I: The flagellum

During epididymal transit, a fibre network and an array of vesicles develop in the posterior two-thirds of the midpiece in sperm of the Brush-tailed possum, Trichosurus vulpecula. The fibre network is developed by the time the sperm reach the corpus epididymidis, and is composed of evenly spaced, helically arranged fibres lying immediately beneath the plasma membrane. The angle of these fibrous helices is always counter to that of the underlying mitochondrial helix. Separating the fibre network from the mitochondria is a layer of granular material which develops at the same time, and over the same length of the midpiece as the fibre network. A somewhat tenuous fibre network is found between the fibrous sheath and plasma membrane in the anterior principal piece of sperm from all regions of the epididymis. The array of vesicles is developed by the time sperm reach the cauda epididymidis. The vesicles resemble pinocytotic vesicles; some appear as invaginations of the plasma membrane, and are open to the medium surrounding the spermatozoon by a narrow neck, while others are entirely enclosed within the spermatozoon, and lie at varying distances between the plasma membrane and the layer of granular material.

Uterine response to ovariectomy during the proliferative and luteal phases in the marsupial, Trichosurus vulpecula

The uterine luteal phase in T. vulpecula is not dependent upon the secretions of the CL throughout its duration. Ablation of the CL or ovariectomy after Day 7 of the 26-day oestrous cycle does not result in the termination of the uterine secretory phase. The dependence of the luteal phase on the secretions of the CL is demonstrated by ablation of the CL or ovariectomy on Days 2, 4, 8, 12 and 24 of the oestrous cycle. Ablation of the CL before Day 8 resulted in the inhibition of the impending luteal phase, and the commencement of a follicular phase resulting in oestrus 8 to 9 days later. Removal of the CL or ovariectomy on Days 8 or 12 does not completely inhibit the uterine luteal phase since sufficient precursor of uterine milk is stored in the uterine basal glandular epithelium, thus enabling the endometrium to maintain the secretion of uterine milk.

Development, function, and regression of the corpus luteum in the marsupial Trichosurus vulpecula

Following ovulation, which usually takes place on day 1 of the 26-day oestrous cycle in T. culpecula, a single corpus luteum begins to develop. During the period before the uterine luteal phase begins on day 8 of the cycle, the granulosa lutein cells are active in the synthesis of what appears to be a cholesterol-like substance at a time when the ovarian secretion rates of progesterone are re!atively low. The uterine luteal phase extends from day 8 to day 15 of the cycle. During this phase the ovarian secretion rates of progesterone are relatively high, and reach maximal levels on days 12-1 3. This high secretory activity is manifested in the granulosa lutein cells by an apparent increase in the number of mitochondria, thought to be involved with the conversion of intracellularly stored cholesterol to pregnenolone, and the development of whorl-like configurations of agranular reticulum which are reported to be concerned with the conversion of pregnenolone to progesterone. A drop in progesterone concentration commences in pregnant and non-pregnant females on day 17 of the cycle, when early involution of the corpus luteunl is apparent. By day 20, the corpus luteum regresses to an early corpus albicans, and the ovarian secretion rate of progesterone falls progressively to levels similar to those in anoestrous females.

Cyclical changes in the uterine endometrium and peripheral plasma concentrations of progesterone in the marsupial Trichosurus vulpecula

The proliferation and secretory activity of the uterine endometrium in the marsupial T. vulpecula is examined at the cellular and subcellular levels throughout the 26-day oestrous cycle. The observations described are correlated with measured concentrations of progesterone in the peripheral blood plasma. Evidence cited indicates that there are no significant functional differences in the uterine endometrial secretory activity during the 17.5-day gestation period in pregnant females, compared with those in a normal oestrous cycle. Progesterone assays carried out on blood plasma taken from 20 staged animals throughout the oestrous cycle, five of which were at known stages of gestation, also supports the view that pregnancy does not significantly alter the physiological pattern of the reproductive cycle in this marsupial.

Uterine glandular regeneration during the follicular phase in the marsupial Trichosurus vulpecula

The uterine luteal phase in T, vulpecula extends from day 8 to day 16 of the 26-day oestrous cycle. During this time both uteri are in an active secretory phase which is particularly pronounced in the basal gland cells, where both apocrine and holocrine-type release of a component of the uterine milk occurs. During the follicular phase which follows the luteal phase, uterine glandular regeneration takes place. Prior to mitotic activity in the uterine endometrium, a regenerative process occurs whereby the basal parts of the glands are surrounded and progressively enclosed by differentiating stromal cells, forming a double gland. The mode of regeneration is completed by mitotic activity in the cells of the outer gland while the inner or old gland cells progressively break up, leaving a lumen within the newly formed uterine gland.

Ultrastructural aspects of cartilage and membrane bone differentiation from common germinal cells

The ultrastructural changes associated with the differentiation of adventitious cartilage and of bone from common germinal cells on the quadratojugal of the embryo chick have been described. The point of divergence of the two cell lines from the common germinal cells has been described and the possible point of action of the morphogenetic switch from osteogenesis to chondrogenesis has been discussed.

Long-term alcohol administration. Its effects on the ultrastructure and lipid content of the rat liver cell

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The cytochemical localization of alkaline phosphatase in Escherichia coli at the electron-microscope level

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