Plasma concentration of testosterone in young bulls in relation to age, rate of weight gain and stimulation with human chorionic gonadotrophin.

In 86 bulls ranging in age between 3 and 11 months, the maximal plasma testosterone concentration (n = 7 as well as the mean concentration (n = 7), same samples) were found to increase with age to peak values at 7-8 months with a subsequent decrease. The multiple correlation coefficient for monthly gain as a function of testosterone concentraton and age was 0.85 (P < 0.001), for monthly gain as a function of age 0.84 (P < 0.001) and for monthly gain as a function of testosterone concentration 0.44 (P < 0.001). The deviation in levels of measured plasma testosterone from the curve expressed by multiple regressiuon analyses of testosterone concentration as a function of age was correlated with the average daily weight gain during the testing period of 9 months and found to be not significant (r = 0.21). The difference between concentrations of plasma testosterone after stimulation with human chorionic gonadotrophin (HCG) and the spontaneous maximal concentration of this hormone was not signifiant. High correlation coefficients were found between maximal (r = 0.8) and mean (r = 0.6) concentratiaons of plasma testosterone before and after an injection of HCG (P < 0.001).

Effect of hemicastration on the level of testicular steroids and growth in bulls and boars.

Ten, bull calves of the Norwegian Red breed were hemicastrated at the age of 1 1 2 -3 months . Ten, normal bull calves of similar age served as controls. No significant differences were found in plasma testosterone levels or in weight between the two groups during the ensuing seven-month test period. Eight, male pigs were hemicastrated at 1-2 months of age. Eight, normal male pigs served as controls. Plasma testosterone, androstenone, and body weight were measured fortnightly in all pigs until the age of 6-7 months. Androstenone in adipose tissue was measured from 4-5 months of age. No significant differences were found between normal and hemicastrated animals in any monthly interval. However, when combining the measurement at 5-6 and 6-7 months of age for plasma testosterone and 5alpha-androstenone and 5alpha-androstenone in fat, the normal pigs had significantly higher values than the hemicastrates (p<0.05). The weight of the single testis from the hemicastrated pigs at slaughter nearly equalled the combined weight of both testes from the controls. Thus, hemicastration did not appear to have any significant effect on the level of testicular steroids in plasma in bulls or growth rate in bulls and boars, but did have a slight effect on testicular steroids in plasma in pigs at 5-7 months of age.

Relationship between growth rate in bulls and human chorionic gonadotropin-induced plasma testosterone concentrations.

In the selection of bulls for breeding purposes growth rate is an important characteristic. In this study 411 bulls, 5 to 11 mo of age were subjected to a human chorionic gonadotropin (hCG) stimulation test. Plasma testosterone 7 h postinjection of hCG was related to monthly weight gain in the month of blood sampling and to daily gain from 3 to 11 mo of age. The bulls were divided into two groups according to plasma testosterone concentrations; those with values above and those with values below the average for each age group. Over all ages (5 to 11 mo), the bulls in the high testosterone group had higher monthly (P less than .001) and daily (P less than .025) weight gain than those in the low testosterone group. However, when split into two groups according to age (5 to 7 and 8 to 11 mo), only the older animals showed the relationship described above. The results indicate that determination of plasma testosterone might supplement other criteria in the selection of breeding bulls for beef production. Eight to 11 mo of age, when differences between high and low levels of testosterone were greatest, would appear to be the most suitable period for sampling.

Effect of human fibrin adhesive on the ear. An electrophysiological study of auditory function in the guinea pig correlated to light and electron microscopy of middle ear mucosa and inner ear structures.

The effect of human fibrin adhesive applied to the middle ear has been studied in guinea pig. Auditory function was measured using acoustically evoked brainstem responses. Middle and inner ear structures were studied with light, transmission and scanning electron microscopy. A transitory conductive hearing loss was observed, but after 8 weeks the auditory function appeared normal. Microscopy of the middle and inner ear failed to show any tissue damage.

Oral health status in relation to ethnicity of children in the Municipality of Copenhagen, Denmark.

UNLABELLED: Approximately 25% of children under the age of 18 in the Municipality of Copenhagen have a non-Danish ethnic background, and it is suspected that there may be major inequalities in oral health as a result. OBJECTIVES: The objectives of this study were to describe the occurrence of dental caries in different ethnic minorities, and to analyse whether the dental caries experience of the children may be affected by cultural and behavioural differences. MATERIALS AND METHODS: The study was conducted in Copenhagen as a cross-sectional investigation of 794 children, aged 3 and 5 years old (preschool), 7 years old (Grade 1) and 15 years old (Grade 9). Children of Danish, Turkish, Pakistani, Albanian, Somali and Arabian backgrounds were selected by convenience sampling. Epidemiological data were retrieved from the Danish Recording System for the Public Dental Health Services (SCOR) and sociological data were collected by postal questionnaires. RESULTS: Marked differences in dental caries prevalence were observed when different ethnic minorities were compared to Danish children. These were most prominent for the primary dentition. At age 7, 53% of the Danish and 84% of the Albanian children were affected by dental caries, the mean caries experience was 3.5 dmfs (decayed, missed and filled surfaces) and 13.8 dmfs, respectively. Caries in incisors and/or smooth surfaces was observed in 10% of the Danish children and 48% of the Albanian children. There were cultural differences in dental attendance and self-care practices of children and parents. These socio-behavioural factors may help to explain the differences in dental caries prevalence and severity. CONCLUSIONS: Development of appropriate oral health promotion strategies is urgently needed to improve oral health behaviour and attitudes of parents and children of ethnic minorities. Preventive programs should be organized at local community level in close collaboration with key persons of ethnic minority societies.

Impedance changes elicited by electrocutaneous stimulation.

Electrical stimulation of the skin in the cavum conchae is followed by bilateral changes in the acoustic impedance of the ear due to reflex contraction of the stapedius muscle. A stimulator and a special surface electrode for electrical stimulation of the skin have been developed. The apparatus produces square-wave constant-current pulses independent of the electrical impedance of the electrode and the skin, and its hazard-proof. The effect of five independently variable stimulus parameters upon the elicited impedance changes has been examined in order to find a stimulus producing a large and reproducible impedance change without causing discomfort to the subject. Although a pronounced habituation phenomenon tends to mask the cause to effect relation of the various parameters, the results indicate that an appropriate stimulus is a pulse train of 0.5 s duration, consisting of individual pulses of a frequency of 200 Hz and 1 ms duration. The stimulus is applied at 10-second intervals.

Long-term effect of HCG on plasma testosterone in bulls.

The spontaneous diurnal variation of peripheral plasma testosterone concentrations in four bulls was established and then the long-term effect of a single intravenous or intramuscular injection of HCG on testosterone levels was studied. Intravenous and intramuscular HCG injections produced, within 1/2 hr and 3 hr, respectively, a rapid rise of testosterone to levels equivalent to the highest values seen in the diurnal pattern. A second increase of up to x2 to x3 the highest values of the diurnal cycle was observed 2 days after the injection of HCG, and the testosterone level remained high for at least 3 to 4 days after plasma levels of HCG were no longer detectable. The pattern of diurnal variation after HCG revealed an attenuation of the extensive spontaneous variation and high levels with only slight fluctuations were maintained.

Developmental pattern and sensitivity to down-regulation of testicular LH receptors in the pig.

Testicular receptors for luteinizing hormone (LH) were quantified in 40 pigs between the day of birth and 22 weeks of age. The highest specific binding capacity (fmol hLH bound/mg protein) occurred at about 2--3 weeks of age which coincides with the age when the relative volume of Leydig cells is at a maximum. Significantly lower binding capacity was observed at 7 weeks of age which is the time of maximum Leydig cell regression. hCG was injected intramuscularly to immature (3000 IU, 22 days old) and adult boars (10 000 IU, 30--40 weeks old). Twentyfour h after injection the numbers of available LH receptors were reduced to 6 and 18% of control values, respectively. At this time occupied receptors were at a maximum (90% and 67% of controls, respectively). The total number of LH receptors (available + occupied) was increased 1 h after injection after which a gradual decrease was observed. Three days after hCG administration the total receptor quantities were at a minimum in both immature and adult pigs (59% and 31% of controls, respectively) and returned to control levels 5--7 days after treatment. Thus, pig LH receptors appear to be subjected both 'positive' and 'negative' regulation as previously described in the rat.

Particulate and solubilized LH receptor in the pig and bull testis.

Particulate and Triton X-100 solubilized receptors for luteinizing hormone (LH) in the pig and bull testis were studied. In some of the experiments tissue from the rat testis was included for comparison. LH receptors in the bull and pig revealed very similar association and dissociation kinetics, affinity (Kd = 1.2-1.8 x 10(-10) M), stability and physicochemical properties. Binding capacity was higher in the pig (73 fmol/mg protein) than in the rat (33 fmol/mg protein) and bull (17 fmol/mg protein). Hormone binding stabilized the receptor against thermal denaturation and temperature stability decreased upon solubilization. It is concluded that the properties of the testicular LH receptor of the pig and bull are very similar to those previously described from the rat.

Fine structure and FSH binding of Sertoli cells in the blue fox (Alopex lagopus) in different stages of reproductive activity.

A clearly different Sertoli cell morphology was found in the immature blue fox and in the adults in and out of season. Immature cells had small, basally, located nuclei rich in peripheral heterochromatin, and few cytoplasmic organelles. Sertoli cells from adults in season had basally located, large, convoluted nuclei with homogenous nucleoplasma and prominent nucleoli. The basal and intermediate parts of the cytoplasm contained an extensively developed ER, numerous mitochondria, free ribosomes, lipid droplets and residual bodies, while the apical cytoplasm showed few distinct structures. In Sertoli cells from adults out of season the nuclei were dislocated towards the lumen, and apart from numerous dilated cisternae of ER, there were generally fewer organelles, but more glycogen particles. A marked rise in FSH binding was found towards the breeding season.

Plasma levels of testosterone in bulls. Response to repeated HCG injections.

Administration of 6000 IU HCG to 4 bulls was followed by an elevation of plasma testosterone lasting for 9-13 days. When HCG administration was repeated, the testosterone response was shortened to 4-6 days in 3 bulls due to the formation of antibodies against HCG. The appearance of HCG antibodies coincided with a sharp decrease in the plasma testosterone level, indicating that Leydig cells have to be under continuous HCG stimulation to maintain increased testosterone production. No antibody against bovine LH was detected in the plasma samples containing antibodies against HCG. In one bull the response following the second HCG injection was similar to the plasma testosterone pattern following the first. No antibodies against HCG were found in this bull. Five bulls received 750 IU HCG twice. Following the period with elevated plasma testosterone levels, subnormal levels were observed after both injections. One injection led to decreased levels without development of antibodies against HCG while the second HCG injection led to subnormal testosterone levels concomitant with measurable antibodies against HCG.

Plasma levels of insulin, glucagon and glucagon-like peptide in salmonids of different weights.

Plasma levels of insulin in rainbow trout,Oncorhynchus mykiss, Atlantic salmon,Salmo salar, and Pacific coho salmon,Oncorhynchus kisutch and plasma circulating levels of glucagon and glucagon-like peptide, in rainbow trout and Atlantic salmon, were measured by homologous radioimmunoassays. Hormonal levels were compared against the average body weight of the same group of fish. Plasma insulin levels were significantly correlated (r=0.56, 0.46 and 0.42 respectively) with body weight in all three salmonid species. Moreover, rainbow trout from fast-growing families had significantly higher (p<0.005) plasma insulin levels than did fish from slow-growing families. Plasma titres of glucagon and glucagon-like peptide were always lower than insulin titres and did not correlate with body weight.