The effects of captivity on the electric organ discharge and plasma hormone levels in Gnathonemus petersii (Mormyriformes)

1. Experiment 1 employed a repeated measures design to examine the effects of captivity on sex differences in the electric organ discharge (EOD) of Gnathonemus petersii, newly imported from Africa, and maintained individually or in groups.
2. On the day of import, males exhibited longer durations of phases 2 and 3 of the EOD and lower peak power spectral frequencies (PPSFs) than females.
3. After 14 days in captivity in the laboratory, the sex differences were eliminated. After 37 days of captivity, all sex differences were still abolished, or even reversed depending on housing conditions. Males exhibited the most dramatic changes in EODs and females appeared to have higher testosterone (T) levels than males.
4. Experiment 2 was designed to investigate the effects of captivity on both behavior and endocrine status in 58 newly imported males. In this independent group design, EOD data and blood were collected from subjects over 15 days.
5. Decreases in phase 3 of the EOD and increases in PPSFs progressed over the 15 day experimental period, becoming statistically significant by days 10 and 15, respectively. Regardless of housing conditions, both T and 11-keto T dramatically decreased to near non-detectable levels by Day 5 in the laboratory.
6. Captivity causes rapid and profound changes in the endocrine system which result in dramatic changes in steroid-sensitive EODs. These findings directly link captivity, hormones, and behavior, and show why feral animals brought into captivity usually do not exhibit sexual behavior.

     

The use of toxicokinetics for the safety assessment of drugs acting in the brain

Pharmacological and toxicological studies undertaken on drugs that affect the brain are frequently performed in disparate species under various experimental conditions, at doses often greatly in excess of those expected to be administered to humans, and the findings are extrapolated implicitly or explicitly with scant regard to differences in the biodisposition of the drugs. Such considerations are necessary since:

1. Species;
2. Strain;
3. Gender;
4. Route;
5. Dose;
6. Frequency and time of administration;
7. Temperature;
8. Coadministration of drugs; and
9. Surgical manipulation

are but some of the factors that have been shown to influence the kinetics and metabolism of drugs. This article, using MDMA and other phenylethylamines as examples, provides evidence for the need to measure the exoosure of the drugs and their active metabolites in blood and brain (toxicokinetics) in order that conclusions based only on dynamic, biochemical, or histological evidence are more pertinent. Further, the combined use of toxicokinetic-dynamic modeling can lead to a better appreciation of the mechanisms involved and a more useful approach to the calculation of safety margins.     

The distribution ofActinocyclus normanii (Bacillariophyceae) in estuaries: Field observations and laboratory investigations

Combining the results of field observations from the Eider, Elbe, Weser and Ems estuaries and laboratory experiments it was found that:

1. in German North Sea estuaries the tidal freshwater reaches are the main habitat of the diatomActinocyclus normanii.
2. the residence time within the tidal freshwater reaches is a key factor controlling not only seasonal and spatial densities within one estuary, but also density differences between estuaries;
3. A. normanii is well adapted to strongly changing light situations and thus adapted to estuaries with high vertical turbulent mixing and low values of Zeu/Zmix;
4. the downstream limit of the habitat ofA. normanii is mainly determined by light limitation rather than by hyperosmotic stress.

     

How did the Krummhörn elite males achieve above-average reproductive success?

The wealthy elite males of nineteenth-century Krummhörn (Ostfriesland, Germany) achieved an above-average reproductive success. Membership in the elite class was determined from a list of the 300 richest men in the Ostfriesland district compiled by authorities in 1812. The main components establishing the link between cultural success and reproductive success are

1. differences in the number of offspring owing to differences both in time spent in fecund marriage (mating success) and in rate of reproduction;
2. differences in the probabilities of one’s adult offspring marrying locally vs. emigrating unmarried owing to differential ability to allocate resources that enhance the “social placement” of adult offspring; and
3. differences in the probability of total reproductive failure (lineage extinction).

Contrary to what might be expected, infant survivorship was lowest amongst the richest families. We conclude that to a great extent females’ reproductive decisions contribute to the greater reproductive success of the elite males.     

Experimental problems using electronic particle counters

The following scheme lists the problems which have been and will continue to be encountered in grazing experiments on natural particle assemblages. In some cases there are solutions, but many of the problems listed below remain intractable. To solve them will require innovative approaches, most probably combining the use of particle counters with other techniques to approach the problem to be solved from several angles at once. Variance between samples due to

- statistical causes (especially caused by large particles) and

- differences between experimental bottles and between experimentals and controls at start of experiment. Shifts in particle distribution during experiment due to

- increase in small particles

- growth of bacteria and other organisms due to excretion of grazers and

- breakage during handling by grazers into fragments. Processes, independent of grazing, leading to changes in particle size distribution due to

- primary production

- grazing by additional components and

- bacterial growth on detrital particles and the formation of detrital flocs.

     

Maladie de La Peyronie: Bilan IRM chez 28 patients

Purpose

to determine diagnosis and prognosis value of MRI in Peyronie’s disease.

Material and Methods

thirty one penile MR examinations have been performed in 28 patients aged between 21 and 73. (1 tesla; surface coil; sagittal SET1, axial SET2 weighted, T1 before and after Gadolinium)

- In all cases but one, fibrous plaques were clinically palpable.

- Images were compared with clinical examination and evolution under anti-inflammatory drugs.

Results

- In 3 cases, MRI misdiagnosed one unique plague.

- In 2 additional cases, one of the 2 clinical plaques was not detected.

- In 5 cases, MRI depicted more lesions than palpation.

- Gadolinium Enhancement was always correlated with a good response to anti-inflamatory drugs but this treatment was also useful in one case who showed no enhancement.

Conclusion

MRI can be helpfull in the pretreatment assessment and int he follow-up of Peyronie’s disease.     

Composition chimique elementaire des populations naturelles de Sphaeroma hookeri (Crustace: Isopode Flabellifere). Aspect spatio-temporel

1. Elemental chemical composition of Sphaeroma hookeri Leach of different natural populations from Camargue (Rhône delta) and from the Bassin de Berre (near Marseilles), was studied on samples taken the same day in different populations and on samples collected at different seasons in the same population.
2. Individual analyses of carbon, hydrogen and nitrogen were performed with a Perkin Elmer elemental analyzer. Total inorganic content was obtained for each specimen by weighing the residue after the output of the analyzer.
3. Relative growth in ash, carbon, hydrogen and nitrogen content of the different populations samples was compared by means of Reeve's statistical method.
4. Chemical allometry lines of each population are given. Variability of growth coefficients or mean values in a given population appears from several samples taken in the course of the year.
5. The differences in slope and position have been tested and their significance stated.
6. Growth coefficients of ash, carbon, hydrogen and nitrogen contents show a certain variability among the different populations. But these differences are not always significant owing to the dispersion of the data, a result of the wide individual variation within a population.
7. Much greater significant differences appear from relative positions of the growth lines, and these seem to be due to some ecological factors, among which, for instance, nutriment can lead to a large difference in carbon content.
8. Within a given population no significant difference appears in the growth coefficients of ash, carbon, hydrogen or nitrogen content and therefore the obtained values characterize each population.

     

Effects of prenatal cocaine exposure in the prefrontal cortex of the rat

This work was undertaken in order to assess the organization of the prelimbic area of the medial prefrontal cortex of rats exposed prenatally to cocaine. Pregnant Wistar rats were assigned to the following groups:

1. Cocaine—60 mg/kg body wt/d sc, from gestational days 8–22; 0131
2. Saline;
3. Pair-fed; and
4. Nonmanipulated.

Male offspring were perfused on postnatal days 14 and 30. Six brains per group and per age were embedded in celloidin to calculate the volumes of the prelimbic area; sections from the other six brains were embedded in resin and processed for electron microscopy. Using semithin sections (2 μm) of layers II–III and V–VI, the following parameters were calculated:

1. The fraction of the neuropil occupied by neurons (V_V);
2. The packing (N_A) density; and
3. The numerical (N_V) density.

Qualitative alterations consisted of dispersed profiles of degenerated neurons and dendrites in the medial prefrontal cortex. No significant differences were found in the gross morphometric parameters when the cocaine group was compared with the other groups. A high interanimal variation was shown in the prelimbic volumes of postnatal day (PND) 14 cocaine-treated rats, and a decrease in volumes was detected at PND30. Although there are some alterations in the main afferent cortical target area for dopaminergic input, its gross morphometric parameters do not seem to be sufficiently affected to account for the behavioral alterations referred to as being dependent on this brain region.     

A study on the rate of water transport of the clam katelysia opima in relation to environmental conditions

1. The neutral red technique was employed to study the rate of filtration in Katelysia opima.
2. The weight specific water filtration was found to be greater for younger clams compared to the older ones.
3. The rate of water filtration increased with decreasing salinity.
4. Water filtration was found to increase as temperature increased, reaching a maximum at 35°C. but then sharply decreasing at 39°C.
5. Light had no significant effect on the rate of filtration.
6. Suspended matter was found to affect the rate of water filtration.
7. The rate of filtration was low at high pH and high in low pH.
8. The rate of water filtration was found to be faster during high tide than during low tide.
9. The presence of the parasitic crab, Pennotheris sp., in the mantle cavity of clams had a marked effect on the particle filtration.
10. Accidental cut of the siphon tips had no effect on the rate of filtration.

     

An ecological study of the Ponggol Estuary in Singapore

1. An ecological study of the Ponggol Estuary was conducted from July 1965 to June 1966 and the seasonal data on physical, chemical and biological characteristics were presented.
2. The Ponggol River represents a short, narrow and shallow estuary in Singapore. The river mouth is open throughout the year and water from eastern Johore Straits drains in twice a day at high tide. The upper reach, however, is left exposed at low tide.
3. The Ponggol River was classified as a vertically and laterally homogeneous estuary and was found to exhibit a mesohaline to polyhaline environment.
4. Significant hydrological gradients from the river mouth 10 the upper reach were noted in the river system. Salinity, dissolved oxygen and pH increased towards the mouth of the river and other parameters such as nutrients, dissolved organic matter and turbidity increased towards the source.
5. Although the river received organic pollutants at the upper reach the estuary was able to discharge them fairly rapidly through regular flushing by the tides. The transient rise of organic matter did not appear to impart any serious affect on the biota in the estuary.
6. Over 98% of the phytoplankton consisted of diatoms, most of which were brought into the estuary from eastern Johore Straits. Freshwater forms were relatively few.
7. Phytoplankton biomass was considerably higher than the adjoining waters. and was reduced at the upper reach due to high turbidity of the water.
8. 80% of the zooplankton was composed of dinoflagellates,Difflugia, copepods and bivalve larvae dominating at all sections of the estuary.
9. Percentage composition of the zooplankton showed that dinoflagellates and copepod nauplii predominated at high tide whileDifflugia and bivalve larvae were abundant at low tide.
10. Zooplankton standing crop, in general, was higher towards the source at high tide but the reverse was found at low tide, i.e. standing crop increased towards the river mouth. This was attributed to the process of concentration.
11. Species composition of zooplankton was found to be more or less similar to that of the eastern Johore Straits.
12. The nekton consisted predominantly of small and juvenile fish. Close correlation of fish and copepods was found to be statistically valid and it was concluded that the fish entered the estuary to feed rather than to spawn.
13. The squids formed an important catch of the beach seine unit and were caught throughout the year.
14. The fish population could be grouped into four categories: estuarine components, euryhaline components, marine components and migratory components.
15. Benthic invertebrates were abundant. Commercially important species consisted of prawns,Metapenaeus andPenaeus, and crabs,Neptunus pelagicus andScylla serrata.
16. The river bed was inhabited predominantly by molluscs and the distribution resembled that of the sheltered shore of muddy-sand type.

     

Development and efficiency of a new generation of bioreactors

The development and investigation of high-efficiency bioreactors is one of the primary problems bioprocess engineers have to solve. With increasing efficiency of the bioreactor the downstream processes will be much simplified, energy and costs will be substantially reduced. According to fundamental research on the properties of stirred tank bioreactors the following rules for the design of bioreactors should be observed:

1. Prevent rotational motion of the biosuspension.
2. Generate motion of the biosuspension in the radial and axial direction.
3. Prevent fluid flow in big spaces.

These design rules are in general observed in the development of high-efficiency bioreactors. A selected group of such bioreactors is described.     

Seasonal variation in the biochemical composition of Mytilus viridis at Ratnagiri on the West Coast of India

1. The seasonal variation in the water, protein, fat and glycogen contents of the mussel, Mytilus viridis has been studied for the year March, 1974 to March, 1975.
2. The water level increased during the monsoon season and decreased in summer.
3. The level of protein, fat and glycogen showed correlation with the reproductive cycle of the mussel.
4. The protein level was high when the mussels were mature and dropped during the breeding period.
5. During sex change from male to female in May the protein level remained high whereas during sex change from female to male in October and November it was low.
6. The fat level was high in mature mussels and declined on spawning.
7. The glycogen level was at its peak in immature mussels and low in mature.

     

Sex differences in vascular reactivity to adrenergic agents in the rat

• 1.1.The study was designed to determine if there are sex-dependent differences in vascular reactivity to adrenergic agents.
• 2.2.Vascular reactivity of both aortic and tail artery smooth muscle from male and female rats to various vasoactive agents was assessed. 3.li]The vascular response of aortic smooth muscle to both phenylephrine and isoproterenol were significantly greater in male rats as compared to females.
• 3.4.There were apparent sex differences in responsiveness to the KCl-induced, non-receptor mediated contraction of aortic smooth muscle in that the sensitivity to KCl was enhanced in male rats.
• 4.5.No sex differences were observed in tail artery preparations.
• 5.6.Phentolamine reduced the maximal tension induced by KCl in the tail artery but not aortic artery preparations. This effect was not sex dependent.
• 6.7.No differences in the vascular smooth muscle responsiveness to acetylcholine or sodium nitrate was observed between groups or within different vascular beds.
• 7.8.The increased sensitivity of males to adrenergic challenge could explain in part some of the existing sex differences in cardiovascular disease and hypertension.

     

Development and efficiency of a new generation of bioreactors

The development and investigation of high-efficiency bioreactors is one of the primary problems bioprocess engineers have to solve. With increasing efficiency of the bioreactor the downstream processes will be much simplified, energy and costs will be substantially reduced. According to fundamental research on the properties of stirred tank bioreactors the following rules for the design of bioreactors should be observed:

1. Prevent rotational motion of the biosuspension.
2. Generate motion of the biosuspension in the radial and axial direction.
3. Prevent fluid flow in big spaces.

These design rules are in general observed in the development of high-efficiency bioreactors. A selected group of such bioreactors is described.     

The use of a continuous assay system to show the stimulation of phosphoenolpyruvate production in intact mitochondria by valinomycin and by Mn2+

1. A method for the direct recording of the PEP efflux from isolated mitochondria is described.
2. This method has been used to show the stimulation of PEP efflux by externally added Mn⁺⁺ ions.
3. Valinomycin, uncoupler and oleate were also shown to stimulate PEP efflux.
4. Valinomycin caused an increase in the internal concentration of both PEP and citrate.
5. The results indicate that the major pathway of PEP synthesis in isolated mitochondria is via PEP carboxykinase and the results do not call for an unknown pathway of metabolism.
6. Two interactions between PEP and citrate are described; competition for the mitochondrial interior and the stimulation of PEP production by citrate.

     

Effet des androgènes sur l’activité sportive

Androgenic hormones seem to be of beneficial effects on sports performance:

- they increase motivation, will, aggressiveness, resistance to the stress and to the fatigue, leading to an increase of the training quantity,

- they increase bone mineralization and probably mechanical resistance,

- they stimulate the bone marrow and so, with the erythropoietin, the erythropoiesis,

- they increase the tendancy to hyperglycemia, but with a decrease of the tolerance to the glucose,

- they stimulate the fatty acids mobilization from the adipose tissue, for their utilization in the muscle during the exercise,

- they participate, for the trained sportmen, to a better gestion of the muscle glycogen storage: their utilization during exercise is decreased,

- they increase the lean body mass, with an increase of the protein synthesis and a decrease of the protein catabolism, leading also to an increase of the muscle force under training. There is no beneficial effect upon the tendons,

- they have an immunomodulation action.

     

Selective phonotaxis to advertisement calls in the gray treefrog Hyla versicolor: behavioral experiments and neurophysiological correlates

1. The significance of particular acoustic properties of advertisement calls for selective phonotaxis by the gray treefrog, Hyla versicolor (= HV), was studied behaviorally and neurophysiologically. Most stimuli were played back at 85 dB SPL, a level typically measured at 1–2 m from a calling male.
2. Females preferred stimuli with conspecific pulse shapes at 20° and 24°C, but not at 16°C. Tests with normal and time-reversed pulses indicated the preferences were not influenced by the minor differences in the long-term spectra of pulses of different shape.
3. Pulse shape and rate had synergistic or antagonistic effects on female preferences depending on whether the values of one or both of these properties in alternative stimuli were typical of those in HV or heterospecific (H. chrysoscelis = HC) calls.
4. More auditory neurons in the torus semicircularis were temporally selective to synthetic calls (90%) than to sinusoidally AM tones and noise (< 70%).
5. Band-pass neurons were tuned to AM rates of 15–60 Hz. Neurons were more likely to be tuned to HV AM rates ( < 40 Hz) when stimuli had pulses with HV rather than HC shapes.
6. Sharp temporal tuning was uncommon and found only in neurons with band-pass or low-pass characteristics.
7. Many neurons differed significantly in response to HV and HC stimulus sets. Maximum spike rate was more often elicited by an HV stimulus (74%) than by an HC stimulus (24%).
8. Differences in spike rates elicited by HV and HC stimuli were attributable to combinations of differences in the rise times and shapes of the pulses.

     

Studies on the selective agents operating in experimental populations ofTisbe clodiensis (Copepoda,Harpacticoida)

In order to determine the biotic selective factors affecting the fitness of genotypes in the polymorphic speciesT. clodiensis, five types of experimental populations were utilized:

1. Populations started with equal numbers of virgin females and males of the three genotypes (pp, pP, PP) at f(p)=f(P)=0.5 in Hardy-Weinberg proportions;
2. Populations started with equal numbers of heterozygous females and males;
3. Populations started with equal numbers of recessive homozygous females and dominant homozygous females, each fertilized by males of the same genotype;
4. Populations with virgin females and males of the three genotypes at f(p)=0.2, f(P)=0.8 in Hardy-Weinberg proportions;
5. One population as in (4) but with f(p)=0.7 and f(P)=0.3.

The populations were sampled at about three weekly intervals in order to follow the gene frequencies for about fifteen generations. A comparison between group (3) and other groups suggests that interaction between genotypes may affect the survival of the genotypes concerned. Comparison of groups (1) and (2) seems to indicate that sexual selection is also involved. The estimated selective coefficients, which appear to vary in different periods and groups of populations, lead to the conclusion that fitness inT. clodiensis is a function of the genetic structure of the population as well as of the population density. The selection pressure is then determined by a great number of biotic components operating in different stages of the life cycle; and it seems reasonable to conclude that inT. clodiensis, at least under these experimental conditions, a frequency-dependent selective mechanism is involved.     

Serum chemistry profiles for Lechwe waterbucks (Kobus leche): Variations with age and sex

• 1.1. Over an 8-year period, 19 biochemical parameters have been determined at various ages in the blood serum of 92 clinically healthy Lechwe waterbucks (Kobus leche), 33 males and 59 females.
• 2.2. Significant differences have been noted with age. In neonates, the lowest values of total proteins, glucose, creatinine, urea, AST, ALT and iron have been noted; the highest ones have been seen for cholesterol, alkaline phosphatase, calcium and phosphorus.
• 3.3. With regard to sex, raised values of glucose, urea, alkaline phosphatase and ALT, and lowered values of cholesterol, have been noted in juvenile females compared with males of the same age.
• 4.4. In adult females, higher levels of urea and cholesterol and lower levels of glucose, triglycerides and natrium have been recorded compared with males.
• 5.5. With sex and age, no significant changes have been found in the levels of GGT, magnesium, chlorides and copper.
• 6.6. Out findings are discussed with those abstracted from the literature for related species.