The record of daily growth in otoliths of Atlantic silversides, Menidia menidia, from field and laboratory

Otoliths were removed from field-collected silversides of age less than 3 months. Otolith diameter was highly correlated with total length of the fish. Daily growth ring counts for this species are known to be a function of age rather than size, so widths for the daily growth rings provide a record of daily increases in length of the fish. Measurement of ring widths showed that weekly specific growth rate was greater than 70% at age 1 week, but declined to about 30% at age 1 month and about 15% at age 2 months. A laboratory experiment in which temperature was changed on a weekly basis demonstrated that environmental variables can affect the width of rings. Nevertheless, the growth rate of field-collected fish, as calculated from otolith ring widths, was more highly correlated with size of fish, as measured by otolith radius, than with the environmental variables of temperature, salinity and plankton abundance. Back-calculation of growth rates from otolith ring widths of five fish collected at the end of the growing season yielded the same age-growth curves as were obtained from 203 fish collected biweekly during the season.     

Static intraspecific allometry of the dentition in Otoletnur crassicaudatus

Adult static intraspecific allometry of tooth size was evaluated in a sample of 66 Otolemur crassicaudatus (34 male, 32 female). Tooth areas were calculated from mesiodistal and buccolingual measurements of canines and postcanine teeth of both arcades and were scaled to four viscerocranial measurements: bimaxillary width; maxillo-alveolar length; mandibular length and bigonial width. Individual tooth crown areas were also scaled to total skull length, body length and body weight. From the log-transformed analyses it is concluded that postcanine tooth size was unrelated to body length or weight, and poorly correlated to skull length or jaw size. Although viscerocranial size appears to be independent of body size, these measures are well correlated to skull length. It is shown that the longer the skull, the shorter and narrower the maxilla, and the longer and broader the mandible. Canines are shown to scale negatively allometric to skull length, hence, large animals will have relatively small canines.     

Macroscopic and roentgenographic anatomy of the skull of the ferret (Mustela putorius furo)

Normal macroscopic and roentgenographic features of the skull of the ferret (Mustela putorius furo) were examined and described. Data were based on a sample of 100 (50 male and 50 female) adult ferrets of known body weight and age. The skull was described macroscopically according to six standard views, i.e. dorsal, lateral, ventral, caudal, cranial and midsagittal. The mandible was described separately. The roentgenographic characteristics of the ferret skull were demonstrated only in lateral and dorsoventral projections. Furthermore, the skull length and width as well as the minimum frontal width were measured, and skull indices were derived from relevant measurements. Sexual dimorphism was examined both morphologically and craniometrically. Besides the common features of a carnivore skull, the ferret skull is relatively elongated and flat with a short facial region. The skulls of adult male ferrets are about 17% longer and 22% wider than those of the females. Significant sexual dimorphism also exists regarding certain skull indices. The general features and some dimensional parameters of the adult ferret skull support the contention that the ferret would be an interesting and workable alternative animal model in craniofacial research.     

Roentgen cephalometric studies on skull development in rats. II. Normal and hypophysectomized males; sex differences

Growth of the skull in normal male rats of the Long-Evans strain has been studied by serial roentgen cephalometry (under anesthesia) from 27 to 280 days of age, and has been compared with the retardation following hypophysectomy and with growth data obtained on females in an earlier similar study. The dimensions measured represented major skull regions and segments, and in some instances allowed calculation of indices (e.g., neurocranial width/length ratio) which would show changing proportions. In general, the skull showed the more rapid and prolonged growth characteristic of male rats' skeletal development when compared with that of females. Viscerocranial (“facial”) length and width were notable in this respect. On the other hand, growth in neurocranial width and height ceased at a time and size much like that in females. Examination of the possibility that the adult female skull might correspond closely to that of an immature male disclosed that though this might be true for the neurocranium, facial dimensions showed distinctive sex differences. After hypophysectomy at 27 days of age males (as also females) showed marked reduction of growth but not complete cessation. Dimensional increases were between one-fifth and one-fourth of the normal gains. The ratios computed showed that the proportions of infancy were retained after early hypophysectomy.     

Femoral expansion in the adult male rat

The length, total and cortical widths at midshaft, and robusticity of femora were measured in growing and mature male Holtzman rats. Analysis of covariance revealed significant differences in the regression coefficients (slopes) between young rats (1-4 months) and adult rats (5-16 months), indicating that, for a given increment in femoral length, young rats have a smaller increment in total femoral width than do adult rats. In addition, the results indicated that femoral expansion occurs in adult male Holtzman rats (5-16 months of age) without cortical thinning or loss of bone mass.     

Occlusal force and craniofacial biomechanics during growth in rhesus monkeys

The masticatory muscles in 132 anesthetized male and female rhesus monkeys ranging in age from juvenile to adult were unilaterally stimulated. Muscle forces and speeds were measured with a bite force transducer positioned at the incisors, premolars, and molars during twitch and tetanic contractions. Lateral cephalographs of all animals were used to estimate the orientation and mechanical advantage of the masticatory muscles. Results showed that maximal occlusal forces increased at a greater rate than body weight during growth. However, maximal occlusal forces increased isometrically relative to mandibular length. Mean forces at the incisors ranged from 70.3 newtons (n) in juveniles up to 139.9 n in adult males. Forces at the molars were 2-2.5 times greater than at the incisors. Time-to-peak tension decreased with increasing body size from 44.1 msec in juveniles to 37.4 msec in adult females to 31.0 msec in adult males. Regression analysis showed that adult males have faster muscles than adult females or juveniles even when corrected for body size. Temporalis and masseter orientation was found to change little throughout growth. The mechanical advantage of the masseter and temporalis muscles for producing occlusal forces on the distal molars improved between juveniles and adults, which is contrary to findings of Oyen et al. (Growth 43:174-187, 1979). Among adults, females had a greater mechanical advantage of the masseter muscles than males.     

Cranial ontogenetic variability,sex ratio and age structure of the Red fox

Describing the sex ratio, age structure of the population and ontogenetic variability of Red fox, Vulpes vulpes (Canidae, Carnivora) skull parameters, this study is based on 416 male and 289 female skulls collected in the Czech Republic. The skulls analysed came from feral individuals, that were shot by hunters. The male to female ratio was 1:0.69 regarding the whole population. Individuals younger than one year prevailed in the population (54% males, 48% females were in their first year of life). Four growth patterns of skull dimensions were described. The first group included mainly skull length dimensions (e.g. condylobasal length). They grew rapidly until the sixth month of life, becoming stabilised afterwards. The second group comprised parameters that were stable throughout the life (e.g. cheek tooth rows). Measurements representing the third growth pattern showed continual growth (mainly width dimensions, e.g. zygomatic breadth). Conversely, smaller dimensions of postorbital breadth were observed after the sixth month of life. Postorbital breadth represented the fourth growth pattern. It was concluded, that male and female Red foxes had similar ontogenetic skull development, even though there were some differences, e.g. in jugular breadth, which increased after the age of six months in males unlike in females.     

The growth of the skull and jaw muscles and its functional consequences in the New Zealand rabbit (Oryctolagus cuniculus)

Between weaning and adulthood, the length and height of the facial skull of the New Zealand rabbit (Oryctolagus cuniculus) double, whereas much less growth occurs in the width of the face and in the neurocranium. There is a five-fold increase in mass of the masticatory muscles, caused mainly by growth in cross-sectional area. The share of the superficial masseter in the total mass increases at the cost of the jaw openers. There are changes in the direction of the working lines of a few muscles. A 3-dimensional mechanical model was used to predict bite forces at different mandibular positions. It shows that young rabbits are able to generate large bite forces at a wider range of mandibular positions than adults and that the forces are directed more vertically. In young and adult animals, the masticatory muscles differ from each other with respect to the degree of gape at which optimum sarcomere length is reached. Consequently, bite force can be maintained over a range of gapes, larger than predicted on basis of individual length-tension curves. Despite the considerable changes in skull shape and concurrent changes in the jaw muscles, the direction of the resultant force of the closing muscles and its mechanical advantage remain stable during growth. Observed phenomena suggest that during development the possibilities for generation of large bite forces are increased at the cost of a restriction of the range of jaw excursion.     

Pubertal neurocranium growth in thymectomized rats

Differences in neurocranium growth at puberty were studied in rats of both sexes thymectomized and sham-thymectomized at 2, 4, 6, 8, 10, 12 and 14 days of age and in controls of matched age and sex; skull length, width and height, and skull base length and face length were measured. The neurocranium of the thymectomized rats was significantly smaller than that of the sham-thymectomized and control rats of both sexes and in all age-groups.     

Effects of growth hormone injection to embryos on growth and myosin heavy chain isoforms in growing turkeys (Meleagris gallopavo)

Effects of embryonic imprinting with growth hormone (GH) on growth and myosin heavy chain (MyHC) isoforms in pectoralis muscle were determined by injecting turkey embryos with ovine growth hormone (oGH) at a dose of 10 μg three times a day. Injections were made on days 20 and 26 (Treatment 1), days 14 and 20 (Treatment 2) or days 14 and 26 (Treatment 3) of incubation. In Treatement 1 poults, plasma GH concentrations were elevated at 3 days posthatch and in Treatment 3 poults, plasma GH concentrations were elevated at 15 days posthatch, as compared to control poults. At 4 weeks of age, in males, body weights, shank length and weights of pectoralis, gastrocnemius and sartorius muscles were increased in Treatment 3, and in females, body weights, shank length and weights of gastrocnemius muscle of female turkeys were increased in Treatment 1. The growth rate of female turkeys from 4 weeks through 16 weeks was increased by Treatment 1. Treatment 1 resulted in a delay in the transition from the embryonic MyHC isoform to the neonatal MyHC isoform and to the adult MyHC isoform. Treatment 3 induced an earlier appearance of the adult MyHC isoform. No effects on body and muscle growth and MyHC isoforms were observed by Treatment 2.     

Biology of the rice rat (Oryzomys palustris natator) in a laborabory environment. X. Postweaning growth of the skull.

A survey of skull development of the rice rat (Oryzomys palustris natator) covering a period of 21 days to 16 months involving equal numbers of males and females (108) was undertaken using various skull parameters. Sexual dimorphism in relation to body weight and length emerged before that of the skull which was only clearly marked by 2 months. A number of the skull parameters by virtue of their individual growth potential did not show sexual differences in size for a long time, whereas others were clearly marked. Once the differences between the sexes had been established they were maintained. One parameter - lenght of cranium - represents those parameters which show changes and it was found that the male rat continued to show a steady linear increase in length up to 16 months, whereas the female cranial length shows a deceleration with termination around 12 months. The skull differences are mirrored in the weight and length findings and it suggested that the earlier sexual maturity of the females is compensated by an earlier cessation of growth compared to the males which mature later and have a correspondingly later cessation.     

A longitudinal study of the growth pattern of the maxillary sinus in the pig-tailed macaque (Macaca nemestrina)

The ontogeny of sexual dimorphism in maxillary sinus size in a nonhuman primate was studied longitudinally for a period of 8 years in 25 female and 25 male Macaca nemestrina via lateral cephalograms. The maxillary sinus was traced and its area digitized. The growth of female maxillary sinuses was described with a Gompertz model; the best fit to the male data was obtained by the logistic model. Growth curves and confidence intervals revealed that the sinuses grew in a similar fashion for 3-4 years in both sexes. After this, female sinuses achieved a plateau in their development while male sinuses continued to grow. Confidence intervals suggested that size dimorphism appeared at the age of 6.3 years. Lowess regression indicated growth spurts in both sexes. Females experienced an earlier and smaller spurt than males. Sexual dimorphism in maxillary sinus size seems to represent a combination of differences in velocity and length of growth. This study indicates that growth of the maxillary sinus follows closely the growth in body size. Nevertheless, due to the variation in sinus size in Macaca, it is questionable if body size is the main determinant of maxillary sinus size. It is suggested that Macaca, with its wide geographic range and different environments, is an especially appropriate genus to use to test hypotheses about the evolution of skull pneumatization in primates.     

Maxillary changes and occlusal traits in crania with artificial fronto-occipital deformation

Artificial fronto-occipital deformation of the cranial vault was typical of pre-Columbian cultures in the central Andean coastal regions. We have studied the influence of this deformation on maxillary and mandibular morphology. Measurements were performed on 86 adult Ancon skulls with anteroposterior deformation. Undeformed skulls from the area of Makatampu (n = 52) were used as the control group. To explore the influence of the deformity on occlusion, the skulls were categorized using the Angle classification and the alignment of the interincisor midline. In the group of deformed skulls, there was an increase in lateral growth of the vault and of the base of the skull (P < 0.001), giving rise to a greater interpterygoid width of the maxilla (P < 0.001), and an increase in the transverse diameter of the palatal vault. The mandible presented an increase in the length of the rami (P < 0.001) and in the intercondylar width, with no alteration of mandibular length. The deformed skulls had normal (class I) occlusion, with no displacement of the midline. The difference in the asymmetry index between the two groups was not statistically significant. Artificial fronto-occipital deformation of the cranial vault provoked compensatory lateral expansion of the base that was correlated with the transverse development of the maxilla and mandible. Occlusion and sagittal intermaxillary position were not affected by the cranial deformity. These results provide evidence of the integration between the neurocranium and the viscerocranium in craniofacial development, and support the hypothesis of a compensatory effect of function.     

Photoperiodic regulation of gonadal growth and pulsatile luteinizing hormone secretion in male ferrets

Testicular growth was monitored in male ferrets subjected to one of the following photoperiodic treatments begun at weaning (8 weeks of age): 8 hr light/day (short days), 18 hr light/day (long days), or short days followed by transition to long days at either 10, 12, or 14 weeks of age. Mean ages to achieve adult testis width of greater than or equal to 12 mm were 27.5 +/- 1.3, 25.0 +/- 1.5, 23.6 +/- 2.9, 20.0 +/- 0.8, and 21.2 +/- 1.0 weeks in ferrets raised from weaning in long days, raised from weaning in short days, and transferred from short to long days at 10, 12, or 14 weeks, respectively. This criterion was met significantly earlier by ferrets experiencing the photoperiod transition at 12 or 14 weeks of age than by ferrets housed in long days from weaning. At the end of the experiment (30 weeks of age), mean testis width was significantly smaller in ferrets raised in long days from weaning or transferred to long days at 10 weeks of age, compared to that of the other three groups (p less than 0.05). In a second experiment, photoperiod experience with long or short days was begun at birth, and testicular size was monitored for a longer period of time. The time courses for testicular maturation were similar to that obtained when these treatments began at weaning. By 40 weeks of age, mean testis width of ferrets raised in long days was comparable to that of ferrets raised in short days. A third study determined that the retarded testicular growth observed in ferrets exposed to long days from weaning was correlated with diminished pulsatile luteinizing hormone (LH) secretion. At 28 weeks of age, mean LH pulse frequency was 0.86 +/- 0.09 pulses/hr in ferrets undergoing spontaneous puberty in short days or photoinduced puberty after a short-to-long-day transition; pulse frequency was significantly lower (0.46 +/- 0.26 pulses/hr; p less than 0.05) in ferrets raised in long days. These results indicate that gonadal growth can be precociously induced in male ferrets by exposure to a sequence of short days followed by long days, and that the absence of sufficient prepubertal exposure to short days compromises pulsatile LH secretion and rate of gonadal growth. Experience with short days during development may be necessary for manifestation of stimulatory responses to long days.     

Effects of the anabolic steroid nandrolone phenylpropionate on craniofacial growth in rats

Primary testosterone and its derivatives are anabolic steroids used in the treatment of osteoporosis and Turner syndrome. They also enhance fast-twitch muscle weight in female rats. The present study examines the effect of an anabolic steroid on craniofacial growth and development in rats. Five-week-old female Sprague-Dawley rats (125) were divided into experimental and control groups. The experimental group was injected subcutaneously with 1 mg nandrolone phenylpropionate in the interscapular region on alternate days, whereas those in the control group were injected with a vehicle, arachis oil. Rats were sacrificed at 60 and 120 days of age. Cephalometric analysis of soft X-ray cephalograms showed that chronic administration of the anabolic steroid, nandrolone phenylpropionate, resulted in: (1) about a 20% increase in body weight, (2) an increase in total skull length, (3) elongation of the maxillary and mandibular incisors, (4) an increase in the depth of the antegonial notch, and (5) downward-forward growth of the viscerocranium against the neurocranium. These results suggest that nandrolone phenylpropionate may accelerate craniofacial growth and/or induce high functional activity of the masticatory muscles in female rats. © 1994 Wiley-Liss, Inc.     

Craniometric allometry in the thicktailed bushbabyOtolemur Crassicaudatus

Static adult craniometric allometry was evaluated in a sample of 66Otolemur crassicaudatus skulls (34 males, 32 females). Although cranial measures were equally well correlated to skull length in males and females, there were noteworthy differences in the exponential values between the sexes. These results underlined the need for caution when allometric analyses are based on pooled data. From the cranial allometric analyses it is concluded that the longer the skull, the shorter and the narrower the maxilla, and the broader the bizygomatic distance. Although cranial length increased proportionately to the increase in skull length, the cranial width in females was positively allometric whilst in males it was negatively allometric. Allometric analyses of mandibular dimensions suggest that larger animals will have proportionately longer mandibulae, which will, in turn, be relatively wider across the gonia, yet shallower behind the first molars. It is postulated that the disproportionate widening of the zygomata might be related to the widening across the gonia.     

Catch-up growth in short-at-birth NICU graduates

The statural catch-up growth, defined as reaching at least tenth length/height percentile (P10) for normal population standards (-1.28 SD score, SDS), was studied in 73 infants short at birth (length < P10 for gestational age) admitted to NICU. Mean gestational age at birth was 35.2 weeks (range 29-41) and mean birth length standard deviation score -2.31 (-4.52/-1.46). Infants were measured at birth, at 3, 6, 12, 18, and 24 months corrected age and then once a year until 6 years chronological age. Statural catch-up growth was studied, with reference both to normal population standards and to individual genetic target. With reference to normal population standards, 44% of infants had caught-up at 3 months of age, 51% at 3 years, 66% at 4 years and 73% at 6 years. In the case of individual genetic targets, a similar trend was present, but the absolute values were slightly higher from 4 to 6 years (73 vs. 66% and 78 vs. 73%, respectively). Statistically significant changes in mean standard deviations score for chronological age were present from birth to 3 months, 3 to 12 months, 3 to 4 years and 5 to 6 years (p<0.05). No differences were found in this trend of recovery when considering ponderal index (PI) at birth (symmetrical vs. asymmetrical), sex (male vs. female) or gestational age (p>0.05). In the majority of cases infants with short stature at birth admitted to a NICU had a statural catch-up growth within the first years of life. This is more evident when considered in relation to individual genetic target rather than to normal population standards.     

短吻舌鳎生长特性的研究

用多元统计分析方法对短吻舌鳎的生长规律、生长特性及雌雄之间的生长差异进行了研究。结果表明：1-4龄的短吻舌鳎处于生长期。在生长速度上,1-2龄生长速度最快。以后生长速度逐渐减慢;在生长方式上,1-2龄体长、体高、体厚的生长基本同步,3龄,体高、体厚生长更快,到4龄。以体厚生长最快;生长方式不同,使不同年龄鱼的体型不同。3-4龄鱼比1-2龄更宽厚;在同一年龄组中,雄鱼不仅显著地小于雌鱼,而且比雌鱼更细长、侧扁,用多项式来描写短吻舌鳎的生长过程,并求出生长拐点年龄为2．35龄。     

Morphometric variation in the Hooded seal (Cystophora cristata)

Intra- and intersexual variation in 16 skull dimensions and total body length of 233 aged Hooded seals caught in the north-west Atlantic were investigated. Absolute growth was described by asymptotic growth curves applied to single dimensions, as well as to scores on the first principal component of logarithmically transformed cranial data, which are believed to reflect the multivariate nature of growth. All dimensions were found to be fully developed later in males than in females. The growth of the male skulls was found to continue for more than 20 years, while the females approach final size about–7 years earlier than males, according to the scores on the first principal component. Female seals were found to reach 86 % of final total body length at the time of maturation, which is a generalized pinniped pattern. In both sexes, a yearling skull was characterized by a large brain-case, which decreased relatively with growth. The male skulls were further characterized by an increase in zygomatic width and orbital width in relation to basal length, a pattern which was not found in females.
All the asymptotic values were significantly larger in males than in females. The dimorphism develops mainly as a result of prolonged growth of males after the attainment of sexual maturity.     

应用阴茎骨鉴定雄性褐家鼠年龄组的探讨

1986年10-11月,作者在长春市研究了城市褐家鼠的种群生态。获得标本 1,214号(531,683),解剖、测量、记录了雄性睾丸重量、长度和宽度,制取了雄性阴茎骨。对其种群阴茎骨长度作了分析,并依据阴茎骨长度作褐家鼠的频数分配,对照体长、体重、睾丸及头骨等特征,划分5个年龄组。分析结果表明,应用雄性褐家鼠阴茎骨划分年龄组,其组间差异显著,组间交叉不大,相对准确,能比较接近实际年龄,故用阴茎骨长度作为划分褐家鼠种群年龄组标准是可行的。