Yr For Males Research Articles

Age and growth of the alfonsino Beryx splendens over the seamounts off New Caledonia

Age and growth of the alfonsino Beryx splendens from New Caledonia seamounts were determined by examination of whole and sectioned otoliths. One growth-ring (annulus) in the otoliths appears to be laid down each year. It consists of one opaque (summer, fast-growing) zone and one hyaline (winter, slowgrowing) zone. Thin-sections of otoliths revealed daily rings which allowed us to estimate that the formation of the nucleus takes ∼10 mo. The first annulus following the nucleus is incomplete. Females have a higher growth rate than males. Sexual maturity is reached at the age of 7 to 8 yr for males and 6 yr for females. Maximum age attained would be ∼20 yr for alfonsino >50 cm in fork length. the results are compared with those from the few other studies on the growth of alfonsino.

Distribution, growth and life cycle of the mesopelagic amphipod Primno abyssalis (Hyperiidea: Phrosinidae) in the southern Japan sea

The vertical distribution, growth, maturation, brood size and life cycle of the hyperiid amphipod Primno abyssalis (formerly P. macropa) were investigated using seasonal samples collected from Toyama Bay, southern Japan Sea, during the period June 1986 to September 1992. Over four different seasons of the year, P. abyssalis was most abundant in the 200 to 350 m strata at night and the 350 to 400 m strata during the day, indicating 100 to 150 m as the general distance of diel vertical movement. Some differences in vertical migrating behavior were noted among juveniles, adult males and females. Population-structure analysis revealed the occurrence of three cohorts aged 0+, 1+ and 2+ yr. Growth as body length in this species is linear with time. Estimated time to complete one life cycle is 1.8 to 2.5 yr for females, but only 0.8 yr for males. Maximum longevity is 2.8 yr. Instar analysis based on the segment number of pleopod rami indicated that newly hatched juveniles molt ten times to reach adult male, and four more times to reach adult female. Adult instar number was found to be only 1 for males and 5 for females. Ovigerous females occurred throughout the year, but the annual peak of release of juveniles from the female's marsupium is estimated to be arly March. Brood size was not correlated with female size, a maximum brood size of 214 eggs was recorded. The dry and ash-free dry weights of instars suggested that juveniles in the female marsupium, adult males, and older adult females are less active feeding or non-feeding stages. Except for the reduced growth rate and the occurrence of small, short-lived males, most characteristics of P. abyssalis are consistent with the present view of the life modes of mesopelagic animals, including linear growth in length, aseasonal reproduction, and smaller brood size coupled with larger eggs.

Validation of otolith-increment age estimates for a deepwater fish species, the warty oreo Allocyttus verrucosus, by radiometric analysis

Otolith increment age estimates for a deepwater species, Allocyttus verrucosus, were validated by comparison with the results from 210Pb:226Ra radiometric analysis. Transverse sectioning and subsequent grinding of otoliths to a thickness of ≃ 0.2 mm revealed increments which provided age estimates for a range of fish sizes. Age estimates ranged from 7 yr for an immature fish of 15.2 cm total length (TL) to 130 yr for a female fish of 36.5 cm TL. Age at maturity was estimated as 28 yr for females and 24 yr for males. In comparison, radiometric analysis of whole otoliths, using a single linear otolith-mass growth-rate model suggested maximum ages of 130 to 170 yr for fish of 34 to 35 cm TL. Radiometric ages were also recalculated using a two-phase otolith-mass growth-rate model in which the growth rate was assumed to slow after maturity to 90% of the pre-maturity rate. This reduced the maximum age to 132±15 yr for a mean fish length of 34.5 cm. Age at maturity for females was estimated at 34 yr. The similarity between age estimates from otolith-increment counts and radiometric analysis strongly supports the accuracy of results from both methods, and encourages further use of such comparisons as an alternative to traditional validation techniques.

Reduced insulin secretion: an independent predictor of body weight gain.

A causal role in the pathogenesis of obesity has been proposed for hyperinsulinemia and insulin resistance in populations with a high prevalence of a "thrifty genotype." An alternative hypothesis is that obesity-induced hyperinsulinemia is an adaptation which, by increasing central nervous system insulin signaling (which suppresses food intake), confers resistance to weight gain. To characterize the relationship between the level of insulin secretion and the risk of weight gain, we examined whether any of three different measures of the level of insulin secretion (the area under the plasma insulin curve during both a meal tolerance test and an oral glucose tolerance test, and the acute insulin secretory response to iv glucose) was predictive of weight gain in a prospective study of 97 Pima Indians (64 males and 33 females) with normal glucose tolerance. During a mean (+/- SD) follow-up period of more than 3 yr (males, 3.58 +/- 1.46 yr; females, 3.02 +/- 1.73 yr), average weight increased 2.1 +/- 3.0%/yr in males and 3.5 +/- 3.6%/yr in females, reflecting a mean annual increase in body fat content of 6.9%/yr in both sexes. Insulin secretion was negatively associated with the rate of weight gain, whether assessed by the insulin response during the meal tolerance test (r = -0.35; P < 0.001), the oral glucose tolerance test (r = -0.30; P = 0.004), or the acute insulin secretory response to iv glucose (r = -0.28; P = 0.002). Moreover, the significance of the relationship between each measure of insulin secretion and weight gain persisted after controlling for differences in age, sex, initial body weight, and insulin sensitivity. Relatively reduced insulin secretion, therefore, is a significant and independent predictor of the tendency to gain weight and adiposity in Pima Indians. The presence of relative insulin resistance also conferred an independent reduction in the risk of weight gain in some regression analyses. We conclude that insulin resistance and hyperinsulinemia are unlikely to play a causal role in the development of obesity, and that relatively reduced insulin secretion is a marker of an increased risk of weight gain in this population. These conclusions support the hypothesis that the level of insulin secretion plays an important role in long term body weight regulation.

Long-term effect of gonadotropin-releasing hormone agonist therapy on final and near-final height in 26 children with true precocious puberty treated at a median age of less than 5 years.

We report a long term study on the effectiveness of chronic GnRH agonist treatment on final or near-final height in 26 patients (20 females and six males) with true precocious puberty (TPP). This study differs from other treatment studies in that the median age at onset of therapy was 4.7 yr for females and 6.2 yr for males, the youngest cohort of treated patients reported to date. We compared patients treated with GnRH agonists who attained final or near-final height with a historical control group of untreated children with TPP (n = 116) matched for mean age of pubertal onset, etiology of TPP (idiopathic or neurogenic), rate of progression, and sex ratio. The current mean height of GnRH agonist-treated females who began therapy at more than 5 yr of age (157.6 +/- 6.6 cm) is already significantly greater than the mean final height of untreated females (152.7 +/- 8.6 cm). The current mean predicted height of the treated females is 164.6 +/- 9.7 cm. The current mean height of females whose treatment was started before 5 yr of age is greater (164.1 +/- 7.7 cm) than that of females whose treatment began after 5 yr of age (157.6 +/- 6.6 cm). The final height of untreated children whose age of sexual precocity was less than 5 yr at diagnosis is significantly less than that of treated patients who were less than 5 yr when they developed TPP (P = 0.0006). The current mean height of GnRH agonist-treated males is 166.3 +/- 12.2 cm, and the current mean predicted height is 170.8 +/- 11.3 cm. This is in sharp contrast to the mean final height of untreated males (155.6 +/- 7.7 cm). The current predicted height correlates negatively with the age at initiation of treatment and the initial bone age and positively with height SD for bone age in the agonist-treated children. The current mean height deviation from target height is significantly less in the 20 treated females (-1 SD) than in 93 untreated females (-2.4 SD; P = 0.006). The mean final height deviation from target height in 23 untreated males (-3.7 SD) is significantly greater than the current height deviation from target height in 6 treated males (-1.7 SD; P = 0.03). The salutary effects of long term GnRH agonist therapy on stature are more clear-cut in the younger treated children. Young untreated children may have the worst outcome with respect to final height.(ABSTRACT TRUNCATED AT 400 WORDS)

High prevalence of joint laxity in West Africans.

Previous surveys have suggested marked ethnic and geographical variation in the occurrence of joint hypermobility. We investigated the prevalence of joint hypermobility and the influences of age, sex, body mass and occupation in a rural Yoruba population in Nigeria. The study sample consisted of 204 individuals aged 6-66 yr from the townships of Igbo-ora and Eruwa in south western Nigeria. Sixty-eight had reported joint pain as part of a population survey of arthritic disorders and each was age and sex matched with one household and one neighbour control. Joint hypermobility was assessed, at four peripheral sites bilaterally and forward flexion of the trunk, by a single observer using the Beighton score. Each subject had weight and height recorded, answered a brief questionnaire about occupation and joint symptoms and was examined for peripheral joint disease. Only 11 (5%) of the subjects were negative at all five sites whereas 111 (54%) were hypermobile at three or more sites including 23 (11%) positive at all five. Using a score of 4/9 or greater as a cutoff, 88 (43%) were positive, including 35% of males and 57% of females. There was a linear decline with age in females but a more rapid decline only to age 35 yr in males. There was no relation to body mass or occupation. We conclude that joint hypermobility amongst this population is substantially greater than that recorded for other groups but is not associated with joint pain.

PRELIMINARY RESULTS OF A MULTICENTER TRIAL OF DEPOT LEUPROLIDE ACETATE FOR CENTRAL PRECOCIOUS PUBERTY

GnRH analogs are now preferred therapy for central precocious puberty (CPP). Although short term trials of the depot preparation of leuprolide acetate (TAP Pharmaceuticals, Inc.) have been reported, results from large series of patients are unavailable. We report the results of GnRH stimulation tests in 127 patients in screening for CPP at 9 centers over a 20 month period. Fifty-three patients (49 F, mean age 7.0 yr) with peak stimulated LH >10 IU/L (DELFIA) and bone age (BA) advancement >1 yr were enrolled in a protocol initiating 300 ug/kg IM q4wk (7.5-15 mg) before age 9 yr in females and 10 yr in males. Follow-up GnRH stimulation tests were performed at 4, 12, 24, 36, 48, and every 24 weeks thereafter; BA was evaluated q24wk. Comparing baseline and 24wk serum levels (mean±SE), estradiol fell from 19.5±4.9 to <5 pg/ml, peak FSH from 13.3±1.1 to 1.1±0.1 IU/L, and peak LH from 33.1±4.4 to 0.8±0.2 IU/L. Peak LH did not suppress (<1.75 IU/L) in one 13 mo' old female until 36 weeks of therapy. No females had detectable estradiol (>5 pg/ml) during therapy, but 3/4 males had transient delectable testosterone (>10 ng/dl). 86% of subjects showed regression or no change in Tanner breast (or genital) stage. Height velocity diminished from 11.5±0.8 to 6.5±0.7 cm/yr, but BA/CA was unchanged in the first 6 mo. There were no local injection reactions. We conclude that depot leuprolide is immediately effective in suppression of pubertal progression and gonadotropin and sex steroid production, but bone age advancement continues in the initial treatment period. Further data will assess the effect of long term therapy upon predicted and final heights.

A community-based study of the epidemiology of asthma. Incidence rates, 1964-1983.

To determine whether the incidence of asthma had increased in Rochester, Minnesota, from January 1, 1964 through December 31, 1983, we used a population-based computer-linked medical diagnosis system to identify individual medical records with diagnosis of asthma or other conditions mimicking asthma. All records were reviewed using explicit predetermined diagnostic criteria; we identified 3,622 incident cases of asthma, including definite asthma (n = 1,547), probable asthma (n = 952), and single wheezing episodes (n = 1,123). The annual age- and sex-adjusted incidence of definite + probable asthma rose from 183 per 100,000 in 1964 to 284 per 100,000 in 1983. This rise was entirely accounted for by increased incidence rates in children and adolescents (age range, 1 to 14 yr); incidence rates for infants younger than 1 yr of age and for adults remained constant. For definite + probable asthma cases, the incidence rates for males were higher than for females from infancy through 9 yr of age and for persons older than 50; incidence rates for females were higher than for males from 15 through 49 yr of age. The median age at onset was 3 yr for males and 8 yr for females. We conclude that asthma begins in early childhood, with a higher incidence and earlier onset in males, and that the increase in incidence rates seen from 1964 to 1983 occurred only in children and in adolescents.

Male-Biased Dispersal in the Great Bustard Otis tarda

We studied dispersal and seasonal movements of Great Bustards marked as young in Villafifila, NW Spain, between 1983 and 1990. This study documented male-biased dispersal in a sexually dimorphic, lekking species; one of the very few documented examples outside the Anatidae. Females nested outside the display area after visiting leks for mating. Males abandoned breeding activities after mating and dispersed during summer to moult. Young stayed with hens until a new breeding cycle was initiated in the next spring. Males dispersed significantly earlier and further from natal sites than females. Home ranges of males were significantly larger during their first two years of life than later, and those of females were significantly smaller than those of males. Average age of first lek attendance was 2.7 yr for males and 1.9 yr for females. Females attended leks closer to natal sites than males, and adult males attended the same leks year after year. Age of first successful breeding was 4-5 yr in females. These results support the hypothesis that sex-biased dispersal is determined by the different value of philopatry for the two sexes.

Age and Growth of the Big Eye Priacanthus macracanthus from the Surrounding Water of Guei-Shan Island, Taiwan.

Age and growth of the big eye Priacanthus macracanthus caught by bottom trawlers in north-eastern Taiwan waters from September 1981 to August 1982, were determined from annuli counts of 1, 172 individuals. Scale resting zones (bands) were formed twice a year, in February and August. The von Bertalanffy growth curve parameters obtained using a nonlinear regression based on age and back-calculated data were as follows: asymptotic length (L∞)=620mm fork length (FL), growth coefficient (K)=0.088, age at zero length (t0)=-1.05 yr for females; and L∞=482mm FL, K=0.113, t0=-0.75 yr for males. Female growth rates were estimated to be 102mm year 1, 44mm year 2, 40mm year 3, and 37mm year 4; male rates were 112mm for year 1, 40mm year 2, 35mm year 3, and 32mm year 4.

Mirogrex terraesanctae (Cyprinidae) of Lake Kinneret: biomass changes in relation to inflow; growth rate in relation to fish/zooplankton interaction

Catch analyses indicate increases in Mirogrex standing stock (exploited phase) from 12000 tonnes in the mid-1980's and a declining abundance after 1986. Brood strength is related to concentrations of influxed organic matter which provide larval food. Estimated von Bertalanffy growth parameters (L ∞ = 164 mm TL, K = 0.25 per yr for males; L ∞ = 198 mm, K = 0.14 for females) denote a low production/biomass ratio compared to temperate cyprinid populations, and a low rate of food consumption. From estimates of zooplankton production in recent years, an average predation of < 3 % fish weight/day is calculated. The decline in zooplankton biomass since 1970 is attributed to overgrazing by Mirogrex at high stock levels. At a lower biomass, the fish population can promote ecosystem stability. Mortality estimates from Mirogrex size distribution in a period of low exploitation were ∼ 1.5 times K-values for both males and females. Similar M/K ratios were estimated for two unexploited cyprinid stocks (Phoxinus phoxinus and Acanthobrama lissneri).

Diagnosis and Management of Delayed Puberty*

THREE percent of children are delayed in developing secondary sexual characteristics, on the basis of statistical considerations (1, 2). The best estimates for current pubertal milestones in North American children are given in Table 1 (3). Males present more often with this complaint, apparently due to the ascertainment bias which results from the psychosocial pressures on small and sexually immature males. The vast majority of children with delayed puberty will prove to have no pathology: such children have constitutional delay (CD) in growth and development. Children with this benign variant of normal growth uniformly possess an excellent prognosis for normal stature and secondary sexual development. On the other hand, they must be distinguished from the small fraction of children with pathological causes of delayed puberty. Characteristic Features of Constitutional Delay The characteristic features of CD are: 1) Puberty is not delayed beyond the chronological age of 16 yr in females and 18 yr in males,

Population Dynamics of the Wandering Albatross, Diomedea exulans, of the Crozet Islands: Causes and Consequences of the Population Decline

Between 1966 and 1985 breeding populations of wandering albatrosses on three islands of the Crozet group decreased at annual rates of 2.6, 4.9 and 6%, but with a rapid decline, at all except one colony, between 1969 and 1975. For the whole study period, the mean age at first breeding was 11.2 yr in females and 12.1 yr in males. Since 1973 birds have bred at younger ages. Breeding success did not vary significantly over time but was correlated with the survival of breeding birds; it was the same for experienced breeders and for birds attempting a first breeding. Adult survival was 90.5% per year during the rapid decline period and 94.4% afterwards. Females appeared to have a higher mortality than males. Immature survival was low (71.5% per year between fledging and 5 yr old) but increased from 1966 to 1980: it was 91.8% per year between ages 6-11 yr. The high adult mortality appears to be the major cause of population decline and is assumed to result from accidental deaths in fishing tackle and from deliberate trapping or shooting by fishermen. Differential survival between males and females is probably due to their distribution when at sea, females foraging more frequently than males in waters where fishing activities occur. Likewise, immatures foraging in similar waters to females have suffered a high mortality. The consequences of the decline for the future of albatross populations in the southern hemisphere is discussed.

Population doses, excess deaths and loss of life expectancy from mass chest x-ray examinations in Japan--1980.

The number of mass chest x-ray examinations in Japan in 1980 was 26.6 million and the average effective dose equivalent was 26 mrem per examination. The genetically significant dose was .017 mrem per person per year, the per caput mean marrow dose was 5.9 mrem, the leukemia significant dose was 5.2 mrem and the malignancy significant dose was 2.8 mrem. The excess deaths were calculated to be 70-280 depending on the risk model used. Those would be in excess to the 3.7 million cancer deaths normally expected among the examined population. The loss of life expectancy calculated with a relative risk model was 38 yr for males and 43 yr for females due to leukemia with a latent period of 2 yr and an expression period of 25 yr, and 12 yr for males and 14 yr for females due to other cancers with a latent period of 10 yr and an expression period of lifetime in the 20-24 age group.

Age and Growth of the Sandbar Shark (Carcharhinus plumbeus) from the Western North Atlantic

Age and growth of the sandbar shark (Carcharhinus plumbeus) was determined from rings in the vertebrae of 475 individuals, tagging data from 220 sharks at liberty for up to 17 yr, and length–frequency data from 2594 individuals. The oldest male sandbar aged in this study was 15 yr old and 154 cm fork length (FL); the oldest female was 21 yr old and 204 cm FL. The sexes grew at similar rates, 5.2–7.3 cm/yr. Females reached a larger adult size. Age to maturity was estimated at 13 yr in males and 12 yr in females. Tag returns indicated that sandbar sharks may live for over 30 yr. von Bertalanffy parameters for males are L∞ = 257, K = 0.0501, t0 = −4.5 and for females are L∞ = 299, K = 0.040, t0 = −4.9.

Mortality in Svalbard reindeer

Mortality rates in Svalbard reindeer followed the “U”‐shaped pattern, with higher mortality rate among calves and old animals than in middle aged individuals. Assuming a stable population size, the mortality data predict a 16.2% annual mortality and recruitment rate among 6 months and older animals, and a male:female sex ratio of 48.5:51.5 among 1‐yr old and older. Both predictions are supported by field data. Female mortality rate increased and differed from the male rate in the age interval 2‐4 yr, while the male rate increased sharply and differed permanently from the female rate in the age interval above 6 yr. First and last breeding are thought to cause the increased mortality among 2–4 and 11–13 yr‐old females. Increased involvement in rutting activities with age associated with lower grazing activity and depletion of fat reserves probably cause the increasing mortality rate among the 6+ yr males. Maximum life span was 17 yr in females and 12 yr in males. Apart from the unknown but possibly high neonatal calf‐mortality, only few animals died during summer or during the rut in autumn. Death among calves, yearlings and most of the females occurred before antler‐shedding in May‐June. Most of the 2‐yr and older males died after antler shedding, which occurs from December among the oldest and during April‐May among the younger males. Hence, the major part of the mortality takes place in spring. The lack of visible subcutaneous and femur fat in most carcasses indicated starvation as the major mortality cause.

Variability in size and age at sexual maturity of argentine, Argentina silus, on the Scotian Shelf in the Northwest Atlantic Ocean

The variability in the length and age at which 50% of individuals were mature was investigated for argentine (Argentina silus) in the Northwest Atlantic. Median length at maturity generally declined with time, the trend more pronounced in females than in males. Males and females matured at similar lengths, but males tended to mature at older ages. From 1965–1969, median length at maturity for males ranged from 35.4 cm in NAFO Subdiv. 4Vs to 26.4 cm in Div. 4W, while that for females ranged from 28.0 cm in Subdiv. 4Vs to 24.9 in Subdiv. 5Ze. From 1965–1969, median age at maturity was about 5.3 yr for males and 4.6 yr for females.

Smoking and mortality in England and Wales, 1950 to 1976

Errors in the certification of the cause of death complicate many studies of the presumed lethal action of cigarette smoking. Such errors can have a serious impact on the analysis of secular trends for specific diseases. In principle, secular trends have the advantage of being able to distinguish between causal, ‘non-causal’ (for example, constitutional) and mixed interpretations of mortality ratios. By studying secular trends in overall mortality, in relation to those of cigarette consumption, problems connected with the incorrect certification of the cause of death are avoided. Percentage changes in sex- and age-specific death rates for all causes of death in England and Wales are calculated, by 3-yearly periods, for the era 1950–1976. These changes in death rates are compared with corresponding trends in sex- and age-specific ‘constant tar’ and ‘current’ cigarette consumption in the United Kingdom. No obvious cause-and-effect relation can be discerned. The main problem is to explain the fairly consistent decrease in death rates in both sexes and all age groups during periods when cigarette consumption was either rising or falling. By considering the age-patterns of the difference in death rates rates between early and late periods the main cause of the fall in mortality in the lower age groups, from 20–24 yr up to 40–44 yr, appears to be the near-eradication of tuberculosis. In the higher age groups, the absence of appreciable structure in the age-pattern of the fall in mortality makes it difficult to identify the causes although up to 70–74 yr in males (but not females) a late mortality form of tuberculosis made a substantial contribution. The trends fail to support the hypothesis that smoking influenced mortality. Rose and Hamilton's randomized controlled intervention trial of the effect of intensive advice to stop smoking has also given no support to the idea that smoking is lethal. The available evidence for mortality in Swedish smoking-discordant pairs of twins (MZ and DZ) lacks statistical power but is consistent with the view that mortality ratios have a constitutional, rather than a (smoking) causal, basis. We should, perhaps, preserve an open mind about the supposed lethal action of smoking.

Incidence of spontaneous pneumothorax in Olmsted County, Minnesota: 1950 to 1974.

Between 1950 and 1974, 318 cases of initial pneumothorax were diagnosed among the residents of Olmsted County, Minn. Seventy-five cases were due to trauma, and 102 were iatrogenic. One hundred forty-one cases were spontaneous in onset, of which 77 were primary and 64 secondary to a specific underlying pulmonary disease. The age-adjusted incidence of primary spontaneous pneumothorax was 7.4/100,000/yr for males and 1.2/100,000/yr for females. For secondary spontaneous pneumothorax, the incidence was 6.3 and 2.0/100,000/yr for males and females, respectively. The ratio of male-to-female incidence was 6.2:1 for primary and 3.2:1 for secondary spontaneous pneumothorax. The differences between the incidence rates for primary and secondary pneumothorax by sex or in total were not significantly different.

Protein-bound iodine level during childhood and adolescence.

ABSTRACT Protein-bound iodine (PBI) and butanol-extractable iodine (BEI) levels were collected from published data on 279 male and female euthyroid subjects between 0.1 and 20 yr of age. After allowing for estimated chemical losses and for the estimated ratio of thyroxine iodine to PBI or BEI, the corrected thyroxine iodine level (B4) was studied for age and sex dependence. Empirical formulae were derived to predict the mean B4 for euthyroid subjects of given age and sex. For females, B4 is about 0.2 μg/100 ml higher than for males, a significant difference (p <0.01). B4 decreases with increasing age to a minimum value at about 15.0 yr for males and 13.7 yr for females, and then rises to approach asymptotically the constant adult level.