The influence of age on the hypothalamo-neurohypophyseal system of the mouse: a quantitative ultrastructural analysis of the posterior pituitary

A quantitative ultrastructural study of the posterior pituitary was undertaken. The posterior pituitary is the storage of the hormones vasopressin and oxytocin. Female C57BL/Icrfat mice which were under conditions of normal hydration were sampled at 8 and 32 months of age. There was a slight age-related decline in the volume fraction of cellular components with a corresponding increase in perivascular space. The proportion of neurosecretory endings and swellings showing autophagic activity (Dellman type II Herring bodies) increased significantly in the senescent mouse. The total pituicyte population showed a significant decrease in volume fraction, but with a significant increase in electron-dense types. Of the subcellular parameters examined, only the diameter of the neurosecretory granules showed a significant age-related decrease, the volume fraction remaining unaltered. The animals used in this study were from stocks found to be in a constant oestrus-metoestrus-like state unlikely to obscure changes in pituitary morphology. Over-all, the morphology of the posterior pituitary of the senescent female mouse under physiologically defined resting conditions indicates maintenance of the status quo.

The effect of osmotic challenge and subsequent rehydration on the aging hypothalamo-neurohypophyseal system. A quantitative morphological study of the supraoptic nucleus

The neurons of the supraoptic nucleus (SON) of male C57BL/Icrfat mice at 6 or 28 months of age were examined from normally hydrated, osmotically loaded and osmotically loaded/rehydrated animals. Using quantitative morphological techniques it was shown that the majority of the ultrastructural variables investigated were controlled in the same way in the SON neurons of young and old mice. The major exception was the mitochondrial compartment which although maintaining a constant proportion of the volume of the SON cell did show a significant reduction in the number of mitochondria in the old group, particularly during the osmotic challenge period of the experiment. The "lipid" body compartment of the SON neuron also behaved differently in the cells from the older age group. This study when viewed in conjunction with previous investigations suggests that these SON neuroendocrine neurons from old animals are able to produce hormone until late in the life-span. However, other aspects of cellular activity appeared to be altered when judged by morphological criteria. It is concluded that the SON neurons from these old mice are able to synthesize hormone-containing organelles to the same concentration as the cells from a younger animal. However, the efficiency of the process, or at least the efficiency of concomitant cellular processes, must be questioned in view of the alterations in the rough endoplasmic reticulum, mitochondrial and lysosomal systems.

Age-related changes in the stomach of the laboratory mouse: a quantitative morphological study

This report is of a quantitative morphological investigation of the gastric wall in the aged laboratory mouse. Male mice of 6, 9, 18, 28 and 34 months of age were killed and the mid-greater curvature of the stomach examined qualitatively and quantitatively for age-related changes. There was no evidence of superficial or atrophic gastritis in any of the mice investigated. There were significant decreases in the relative volumes of parietal and chief cell components with age, and a significant increase in other components in the lamina propria. The relative volume of the mucous cell compartment did not change with age. In all cases where a significant change was observed it took place in the 34-month-old age group when compared with 6-, 9- or 18-month-old animals. There was a progressive change in the components after 18 months of age but this only achieved significance at 34 months. It was concluded that alterations in the gastric wall take place later in the life-span and appear to be a physiological, rather than a pathological change.

The epithelium in the female urethra: a quantitative study

Histological sections were prepared from 8 regions along the length of the urethra in 16 women 19 to 82 years old. The epithelium was examined under the light microscope at 4 points in each region and the type of epithelium was classified. Our results indicate that the human female urethra is lined by stratified squamous, pseudostratified columnar and, occasionally, transitional epithelium. There is a gradual change from squamous to columnar epithelium with advancing age. More squamous epithelium is present at the distal end of the urethra.

The influence of age on the response of the supraoptic nucleus of the hypothalamo-neurohypophyseal system I. Ultrastructural aspects

The influence of age on the response of the supraoptic nucleus (SON) of the hypothalamo-neurohypophyseal system to physiological stress has been studied by means of the electron microscope. An osmotic load was applied to male C57BL/Icrfat mice at 6 and 28 months of age and the resulting changes in the ultrastructure of SON cells in response to this stress analysed. In the young animals the differences in morphology observed between the SON cells from control and from those of salt-loaded mice were very similar to those seen in salt-stressed rats at a similar age. Qualitative differences were noted in several sub-cellular components of old, salt-stressed mice. The mitochondria showed evidence of ultrastructural damage in cells from the old, stressed animals. The Golgi system and the rough endoplasmic reticulum both showed heterogeneity in structure when compared with cells from young salt-stressed mice. In addition, there was a decrease in the lipofuscin content of old, salt-stressed mice. These changes are discussed with respect to the overall efficiency of cellular activity in old, physiologically stressed animals.

Response to dehydration in elderly patients in long-term care

Elderly patients in long-term care have a high plasma osmolality (pOSM) and associated increased mortality. In these patients, we examined pOSM, thirst (visual analogue scale, VAS) and arginine vasopressin (AVP) response to 16-hour dehydration and 2-hour rehydration. Twelve patients were randomly divided into two groups (A & B). Group A had their fluid balance monitored for two weeks, group B did not. Single measurements of VAS, pOSM and AVP were conducted on days 0, 7 and 13. Dehydration tests were conducted in both groups at the start of the study (DAY 1), and at the end of the two-week period (DAY 14). There were no significant differences between group A and B, so the results are presented for the two groups combined. There was a significant increase in both pOSM and VAS during dehydration, and a significant fall in both variables during rehydration [F (9,99) = 18.69, p < 0.001, and F(9,99) = 11.25, p < 0.001, respectively]. Plasma AVP did not change significantly during either dehydration or rehydration [F (9,99) = 0.59, p = 0.8]. There were no significant differences in response for any of the three variables between DAY 1 and DAY 14. We conclude that elderly patients in long-term care exhibit changes in thirst and osmolality during dehydration and rehydration, and that these responses are reproducible. The lack of a significant AVP response requires further investigation.

The structure of the rectal papilla in a parasitoid hymenopteran Nasonia vitripennis (Walker) (Hymenoptera Pteromalidae)

The ultrastructure of the rectal papillae of the parasitoid hymenopteran, Nasonia vitripennis (Walk), is described. These organs in this insect consist of four distinct cell types arranged as a closed, hollow cone. The majority of the cells are present in the raised cone, and are characterised by large numbers of mitochondria arranged in a membranous labyrinth. A series of cells form a collar around the base of the cone. Junction cells have been identified which are present at the point of insertion of the cone into the rectal epithelium. The base of the cone consists of cells with elaborately folded plasma membranes facing both the central cavity of the cone, and the haemolymph. The structure of this rectal papilla is compared with those found in other insects.

Production of consistent crush lesions of murine skeletal muscle in vivo using an electromechanical device

The crush model of injury in skeletal muscle is widely used in the investigation of tissue degeneration and regeneration. Previously, such trauma has been induced by using forceps to crush the muscle, commonly applying sufficient pressure to bring the mid-arms of the forceps together. This report introduces a reliable electromechanical device designed to generate reproducible focal lesions in skeletal muscle of mice. The tibialis anterior was crushed in 17 young adult mice. Two days after injury, the muscles were examined microscopically. By morphometric analysis, it was determined that the volumes of the lesions produced were similar (mean 0.499 mm3 +/- 0.098, range 0.278 - 0.601 mm3), and that the full extent of the damaged muscle was easily distinguished and readily quantifiable. This will allow a more precise comparison in future investigations into regenerative differences between age groups, satellite cell activation and the inflammatory response.

A study of the effect of diet on the life-span of Nasonia vitripennis (Walk.) (Hymenoptera, Pteromalidae)

The effect of diet on the life-span of female Nasonia vitripennis (Walk.) has been investigated. Life-tables were constructed for these insects fed on dipteran puparia and on 10% sucrose; Further experiments were performed involving the transfer of females from the sucrose diet to puparia at different ages. The converse experiment was also carried out. From this work it was shown that the insect is capable of a greatly extended life if fed sucrose for all, or part of its life-span. However, transfer from puparia to sucrose after 15 days allows an increased survival for only a small percentage of the population. The results are discussed with regard for the age at transfer and to the reproductive physiology of the insect.

The ageing hypothalamo-neurohypophysial system. An analysis of the neurohypophysis in normal hydration, osmotic loading and rehydration

Age-associated changes in the structure and function of the neurohypophysis may contribute to the decreased ability to conserve water in older animals. We investigated the neurohypophyses of 6 and 28-month-old male mice using radioimmunoassay and quantitative morphological techniques. The dry-weight and volume of the neurohypophysis increased significantly with age but the quantity of vasopressin in the gland remained constant. Oxytocin levels decreased with age. A quantitative morphological analysis was performed on the compartments of the neurohypophysis from male mice of 6 and 28 months of age which were either normally hydrated, osmotically loaded, or osmotically loaded and rehydrated. The absolute volumes of the axon endings, swellings, their constituent organelles and the axon terminals containing degenerating subcellular components were determined. The design of the analysis allowed us to examine both age-related changes and statistical interactions between the age of the animal and the behaviour of a variable during the osmotic loading/rehydration phase of the experiment. There was a significant age-related reduction in the volume of the neurohypophysis occupied by the endings and swellings. The diameters of the neurosecretory granules found in the endings were significantly smaller than those in the swellings in both age groups but the size difference was greater in the young animals. Dehydration and subsequent rehydration of old male mice leads to extensive re-modelling of the neurohypophysial compartments and subcellular organelles to the configuration found in the adult animal.

Perception of Slope and Distance in Photographs and in the Real World

We report a series of experiments in which spatial judgments of the real world were compared with equivalent judgments of photographs of the real-world scenes. In experiment 1, subjects judged the angle from the horizontal of natural slopes. Judgments of slope correlated with true slope (r=0.88) but judgments were in general overestimates. Equivalent judgments of slope in photographs again correlated with true slope (r=0.91) but judgments tended to be overestimates for small angles (6°) and underestimates for larger angles (up to 25°). In experiment 2 slope judgments were made under laboratory conditions rather than in the natural world. The slopes, which were viewed monocularly, varied from 5° – 45°, and were either plain, or textured, or included perspective information (a rectangle drawn on the surface) or had both texture and perspective. Judgments were overestimates, but the correlation with true slope was high (r=0.97). Slopes with either texture or perspective were judged more accurately than plain slopes, but combining texture and perspective information conferred no further benefit. Judgment of the angle of the same slopes in photographs produced similar results, but the degree of overestimation (closer to the vertical) was greater than for the real slopes. In experiment 3, subjects either judged the distance of landmarks ranging from 200 m to 5000 m from the observation point, or judged distance to the landmarks in photographs. In both cases subjects' judgments were well described by a power function with exponents close to one. Although there are large individual differences, subjects' judgments of slope and distance are accurate to a scale factor, and photographs yield similar judgments to real scenes.

Loss of resistance technique for locating the epidural space: evaluation of glass and plastic syringes

Location of the epidural space in epidural anaesthesia usually involves the measurement of loss of resistance using glass or plastic syringes. In the present study two varieties of glass syringe and one plastic type were evaluated to determine the resistive forces associated with plunger movement. The mean static (fs) and dynamic (fd) forces for polished glass syringes having a ground plunger only were fs = 0.47 X 10(-3) +/- 0.22 X 10(-3) N and fd = 0.37 X 10(-3) +/- 0.19 X 10(-3) N and for polished glass syringes having a ground barrel and plunger were fs = 0.43 X 10(-3) +/- 0.16 X 10(-3) N and fd = 0.38 X 10(-3) +/- 0.15 X 10(-3) N. Each of these values was significantly lower (P less than 0.5) than those for plastic syringes fs = 2.22 X 10(-3) +/- 0.48 X 10(-3) N and fd = 1.46 X 10(-3) +/- 0.37 X 10(-3) N. It is concluded that glass syringes are favoured over plastic for locating the epidural space because frictional forces developed with glass syringes were significantly lower than with plastic.

The effect of endotoxin on membrane fatty acid composition in BCG-sensitized mice

The effects of endotoxin on mouse liver phospholipid fatty acid composition have been investigated. Administration of endotoxin from Salmonella abortus equi led to a decrease in the polyunsaturated fatty acid content of livers from mice sensitized with Bacille Calmette Guérin (BCG). The content of arachidonic acid fell significantly in both the phosphatidylcholine and phosphatidylinositol fractions whereas in the phosphatidylethanolamine fraction the linoleic acid content was significantly reduced. The polyunsaturated fatty acids were replaced by increased amounts of oleic acid and palmitic acid, leading to a reduction in the polyunsaturated to saturated fatty acid ratio.

A morphometric and cytochemical analysis of aging changes in the flight muscle of Nasonia vitripennis (Walk) (Hymenoptera, pteromalidae)

A morphometric and cytochemical analysis was carried out on the effect of age and diet on the flight muscles of Nasonia vitripennis (Walk). A significant decline in mitochondrial volume with age is revealed in pupae-fed insects, but this is not recorded in sucrose-fed insects. There is also a significant decline in the activity of cytochrome oxidase in sucrose-fed, but not in pupae-fed, insects. It is concluded that the sucrose diet caused a delay in the ultrastructural deterioration of the flight muscles.

A multi-modality assay platform for ultra-high throughput screening

The demand for increased throughput during primary screening using less reagents is changing the way of drug discovery. Searching for hits using high throughput screening in 96-well format plates is being replaced by the use of higher density plates, such as 384 and 1536-well formats. The analysis of radiometric assays by scintillation counters is becoming limiting since only 12 wells can be counted at a time. Charged coupled device (CCD) camera based instruments, that image the whole plate in one exposure, speed up detection and are compatible with any microplate footprint. Researchers are also demanding a choice of detection methods, including fluorescence, luminescence and radioactivity, and require imagers suitable for all applications. LEADseeker Homogenous Imaging System is a multi-modality platform offering imaging technology and assay toolboxes for radiometric, fluorescent and luminescent based assays. LEADseeker allows the very rapid analysis of high density formats enabling ultra-high throughput screening of a range of biological assays. Research areas that can be studied using this system include enzyme assays, receptor binding and molecular interactions.

Effect of lysophosphatidylcholine on the filtration coefficient in intact dog lungs

Lysophosphatidylcholine (lyso-Pc) is a lysophospholipid normally found in low concentrations in the lung. At high concentrations lyso-Pc, instilled into the airways, causes pulmonary edema. We tested the hypothesis that the edema caused by lyso-Pc was due to an increase in pulmonary microvascular membrane permeability. In 11 anesthetized dogs we continuously weighed the left lower lobes (LLL) while instilling lyso-Pc (20 mM) into the LLL airways. After 30 min we determined the microvascular membrane fluid filtration coefficient (Kf) from the relationship between the rate of LLL weight gain and the pulmonary microvascular pressure. Kf was not significantly different between the lyso-Pc-treated lobes (0.048 +/- 0.018 ml.min-1.mmHg-1) vs. control lobes (0.067 +/- 0.031 ml.min-1.mmHg-1). Our data do not support the hypothesis that lyso-Pc, instilled into the airways, causes an increase in pulmonary microvascular permeability.

Long-term study of the immuno-pathological consequences of sympathetic orchiopathia in the rat

Unilateral testicular ischaemia was induced in Wistar rats by ligation and division of the testicular and deferential vessels. Damage (as assessed by a Johnsen count) to the contralateral testis caused significant spermatogenic suppression only at the equator of the testis at 28 days after operation. Cytotoxic antisperm antibody production increased progressively from 7 to 14 days and became maximal at 28 days after infarction, but after 3 and 6 months antibody production was decreasing. The presence of agglutinating antisperm antibody was noted at 28 days, 3 months and 6 months after infarction. Serum immunoglobulin estimations revealed an increase in IgG and IgM levels at 7 days and IgM levels at 14 days, supporting the contention that an immunological reaction had occurred. It is suggested that unilateral testicular ischaemia in the rat, an animal model intended to mimic torsion of the testis in the human, causes a transient immunological phenomenon (sympathetic orchiopathia) which recovers over the course of time. Caution should be exercised before regarding this relatively common surgical emergency as an aetiology of oligospermia or asthenospermia.

Influence of diet on chromatin organization in insect mid-gut cells, and its implications for the understanding of aging in this model system

Female Sarcophaga bullata were fed on three different dietary combinations: liver/water; sugar/water; and sugar/liver/water. These diets resulted in different survival patterns for the insect, with the longest lifespans being expressed on the last treatment. The Feulgen-DNA values for mid-gut cell nuclei were determined using a scanning and integrating microdensitometer. The cell nuclei of the mid-gut reacted to the presence of nutrients by an increase in the extinction values for Feulgen-DNA when compared to the unfed state. There were also significant differences between the various treatments in the extent of the activation shown by the mid-gut cells. The dietary regimes resulting in the longest lifespan showed a complete and uniform activation of the mid-gut epithelium, whereas other treatments did not. These observations suggest that changes in the chromatin organization occur with diet, and that maximum Feulgen-DNA extinctions occur (i.e. chromatin uncoiled and supporting transcription) on the sugar/liver/water diet. Nuclei showing maximum extinctions do not show an age-related change between 3 and 12 days of life. However, if the nuclear activation is partial, or incomplete, then age-related reversals in chromatin condensation take place.

The glial cell response to a viral vector in the aged brain

The normal aged brain undergoes pro-inflammatory changes. We investigated the effect of injecting a potential inflammatory stimulus, an adenoviral vector, on the response of microglia and astroglia in the aged brain. Groups of young (4 months) and old (31 months) male C57BL/Icrfat mice received a unilateral injection into the striatum of adenoviral vector encoding the LacZ gene. After 48 h, the mice were killed and the brains analysed for numbers of activated microglia and macrophages using the biotinylated lectin Griffonia simplicifolia as a marker; astroglia were identified by immunohistochemistry for glial fibrillary acidic protein (GFAP). The cell counts were analysed using two-way analysis of variance (anova). Transgene expression was assessed by beta-galactosidase histochemistry. The numbers of activated microglia in the striatum increased in response to the adenovirus in both young [contralateral 19.5 (3.7), ipsilateral 36 (3.0)] and old [contralateral 23.1 (9.6), ipsilateral 40.8 (6.9)] mice (two-way anova; P < 0.0001), but there was no significant difference between the two age groups. There was a significant age-related increase in the number of GFAP-positive astroglia in the uninjected, contralateral striatum [4 months, 2.5 (1.4); 31 months, 29.7 (9.3)] (two-way anova; P < 0.0001). However, there was no difference in response to the adenovirus in both young [contralateral 2.5 (1.4), ipsilateral 3.2 (1.2)] and old [contralateral 29.7 (9.3), ipsilateral 28.9 (8.2)] mice. We conclude that even though it has been argued that the aged brain is in a pro-inflammatory state, under the experimental conditions used in this study, there was no difference in the nature of the immune response between young and old mice of this strain to an adenoviral load.

Contracts to bear children

In the surrogate mother procreation can be divorced both from sex as well as any anticipation of child rearing. Often the risks of surrogate motherhood are presented in terms of alternative family structures and economic exploitation of women. Such possibilities must invite critical reflection in order for there to be legal reform. Of paramount importance is the child's best interest and until the full psychological is the child's best interest and until the full psychological ramifications for the child, adoptive parents and natural mother are determined then the law's role must be ambivalent. In this impasse the minority view of the Warnock Report has much to commend itself.