Biomedical subjects

C C Danielsen

Publications and source records attributed to C C Danielsen.

At least 37 records · Page 2Linked to original sources

PubMed1994

Surgically induced uremia in rats. II: Osseous PTH-susceptible signaling systems as predictors of bone resorption.

Predicting the course of parathormone (PTH)-elicited bone turnover in both humans and experimental rat models with moderate chronic uremia, using only standard clinical chemistry analyses, is often difficult. Consequently, rat bone from 1 + 2/3 nephrectomized animals, after 230 days of progressive renal failure, was examined for PTH-stimulated adenylate cyclase (AC) and phospholipase C (PL-C) activities. Correlations to biological parameters related to the function of bone and kidney were made. Reduced renal function was demonstrated by increased serum creatinine; circulating 1,25 dihydroxyvitamin D3 below detection level; diminished renal PTH-elicited AC activity; and decreased urinary cAMP excretion. PTH-activated renal PL-C was also reduced. However, no significant differences were seen in urine creatinine, calcium, phosphate, and hydroxyproline, nor in serum PTH, alkaline phosphatase, calcium, and phosphate. Notwithstanding, renal osteodystrophy developed as estimated by increased plasticity of the long bones, as well as reduction of the diaphyseal (Dd) and inner femoral mid-shaft (Di) diameters. Femoral cancellous bone exhibited a substantial elevation of both eroded surface (ES) and osteoid surface (OS) as well as a marked reduction in trabecular bone volume (TBV). Calvarial PTH-activated AC was enhanced, whereas corresponding PL-C was markedly reduced. PTH-enhanced AC correlated positively with ES and negatively with Di, respectively. PTH-enhanced PL-C, however, correlated positively with bone calcium content and negatively with ES. Our results indicate that bone modeling and remodeling are to a large extent related to PTH-elicited signaling systems, and cannot easily be predicted by standard clinical chemistry analyses.

Adenylyl Cyclases↗

PubMed1994

The effect on vertebral bone mass and strength of long term treatment with antiresorptive agents (estrogen and calcitonin), human parathyroid hormone-(1-38), and combination therapy, assessed in aged ovariectomized rats.

The aim of the study was to assess the long term effect of the antiresorptive agents estrogen and salmon calcitonin, the anabolic drug PTH, and combination therapy on vertebral bone mass and bone biomechanical competence in aged osteopenic ovariectomized (OVX) rats. Seventy-nine 1-yr-old retired breeder Wistar rats were randomized into seven groups: 1) sham-operated, 2) OVX, 3) OVX plus estrogen, 4) OVX plus salmon calcitonin, 5) OVX plus human (h) PTH-(1-38), 6) OVX plus hPTH-(1-38) and estrogen, and finally, 7) OVX plus hPTH-(1-38) and calcitonin. Treatment regimens were initiated 8 weeks after ovariectomy and continued for 24 weeks. Whole body bone mass was measured by dual photon absorptiometry at intervals of 4 weeks and at death. Changes in spinal bone mass (BMC), biomechanical competence, and structure were assessed from the lumbar vertebral bodies. The results revealed a protective effect of both estrogen and calcitonin on ovariectomy-induced loss of whole body bone mass, but only estrogen had a significant effect on spinal BMC. hPTH-(1-38) monotherapy increased vertebral bone mass (BMC and ash content), size, and biomechanical parameters 20-80% over OVX levels. A more rapid effect on vertebral bone mass was seen when hPTH-(1-38) was combined with estrogen or salmon calcitonin. The study has shown that in aged OVX osteopenic rats, hPTH-(1-38) therapy increases vertebral bone mass and bone quality and also maintains trabecular connectivity. Both estrogen and calcitonin reduce the ovariectomy-induced bone loss, but cannot restore bone mass to sham-operated levels. On the basis of this study, it is concluded that PTH therapy seems to hold promise in the management of postmenopausal and age-related osteoporosis.

Absorptiometry, Photon↗

PubMed1994

Biomechanical analysis of cervix uteri in nonpregnant, pregnant and antigestagen (ZK 98 299) treated pregnant rats.

The biomechanical properties of the cervix uteri of the rat were studied under different pharmacological conditions. Four groups of rats were enrolled: A. non-pregnant (N = 12), B. 18 days pregnant treated with vehicle (N = 14), C. 18 days pregnant treated with the antigestagen ZK 98 299 (Onapristone) for 19 hours (N = 15), D. 22 days pregnant during spontaneous labor (N = 12). Load-dimension curves of two 2 mm ring-preparations from each cervix were obtained by a material testing machine. The results showed that the sampling position, the cervical ripening process, and the influence of antigestagen treatment were reflected in the biomechanical and compositional parameters. In conclusion the methodology in the present study constitute a model in which the effect of pharmaca on cervical ripening can be tested. The study demonstrated that antigestagen treatment induced biomechanical changes in the cervix comparable to those occurring during physiological cervical ripening at term.

Animals↗

PubMed1993

Evaluation of the skeletal effects of combined mild dietary calcium restriction and ovariectomy in Sinclair S-1 minipigs: a pilot study.

A pilot study was conducted to investigate the combined effects of ovariectomy (OVX) with preceding and concomitant mild dietary calcium restriction on the minipig skeleton. Minipigs 4 months old were fed diets containing 0.9, 0.75, or 0.5% calcium (Ca). At 10 months, the 0.75 and 0.5% pigs were OVX and the 0.9% were either sham operated or OVX. All pigs were maintained on their respective diets for an additional 6 months. Excised lumbar vertebrae and long bones were evaluated by densitometry and histomorphometry, and vertebral cancellous bone samples were tested biomechanically. In pigs fed the 0.9% Ca diet, OVX alone effected decreases of 6% in vertebral bone mineral density (BMD), 15% in trabecular bone volume (BV/TV), and 13% in trabecular number (Tb.N), an increase of 15% in trabecular separation (Tb.Sp), and a nonsignificant increase (p < 0.056) in vertebral cancellous final erosion depth (F.E.De) compared with the 0.9% Ca sham-operated group. Decreasing dietary Ca to 0.5% in combination with OVX effected an 8% reduction in vertebral BMD that was not associated with any significant alterations in parameters of vertebral cancellous bone microstructure or remodeling compared with the 0.9% Ca sham-operated pigs. Increases in serum PTH noted in the 0.5% Ca OVX group were generally paralleled by increases in calcitriol. In OVX pigs fed a diet containing 0.75% Ca, a 10% reduction in vertebral BMD was observed. This was associated with significant increases in F.E.De and vertebral marrow star volume (Ma.St.V) compared with the 0.9% Ca sham-operated pigs and the other OVX groups. In addition, Tb.Sp was increased and Tb.N decreased compared with the 0.9% Ca sham-operated pigs. Increases in serum PTH in this group were not accompanied by increases in calcitriol. Midradial and midfemoral BMD values were reduced in the 0.75 and 0.5% Ca OVX groups compared with the 0.9% Ca sham-operated pigs. Histomorphometric analyses of cortical bone suggested the reduction in cortical bone mass in the 0.75% Ca OVX group may have been largely due to net loss on the endocortical surface versus possible failure to accrue bone in the 0.5% Ca OVX group. Ash density and biomechanical parameters for vertebral cancellous bone decreased progressively in the 0.9% sham-operated, 0.9% Ca OVX, and 0.75% Ca OVX groups and then increased in the 0.5% Ca OVX group. After normalization for bone mass (ash), mechanical changes were still apparent, particularly for the 0.75% Ca OVX group compared with other OVX groups, reflecting that structural changes had taken place in the trabecular network.(ABSTRACT TRUNCATED AT 400 WORDS)

Acid Phosphatase↗

PubMed1993

Cortical bone mass, composition, and mechanical properties in female rats in relation to age, long-term ovariectomy, and estrogen substitution.

The study comprised 12 groups of female rats: 6 groups of intact rats killed at 2, 6, 9, 12, 15, and 24 months of age, 4 groups of rats ovariectomized at 6 months and killed together with the intact rats at 9, 12, 15, and 24 months of age, and 2 groups of rats (one intact and one ovariectomized) treated with estrogen (2 micrograms estradiol valerate/rat/week s.c.) for 8 months before they were killed at 24 months of age. The composition, dimensions, and mechanical strength of intact bone and bone collagen from femoral diaphyses were investigated in relation to age, ovariectomy, and estrogen administration. Up to 6-9 months of age, the axial length, percentage ash, density, and compressive mechanical stress increased, whereas percentage collagen decreased. An age-related increase in bone mass, cross-sectional area, and wall thickness and a decrease in mechanical quality of bone collagen were apparent from 2 to 24 months of age. An age-related periosteal bone formation and the absence of endosteal bone resorption were demonstrated in intact rats. Compared with intact rats, ovariectomy was followed by an increase in body weight, a tendency to reduced percentage ash and a depressed bone mass, cross-sectional area, and wall thickness of femoral diaphyses. The compressive mechanical stress of intact bone and the mechanical quality of bone collagen were unaffected by ovariectomy. Ovariectomy did not influence the periosteal bone formation but induced an endosteal bone resorption not present in the intact rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1993

The effect of aging and ovariectomy on the vertebral bone mass and biomechanical properties of mature rats.

Ovariectomy has a proven pronounced effect on bone mass, as has been shown in several animal models and in clinical studies. The aim of this study was to investigate the effect of ovariectomy on both vertebral bone mass and biomechanical competence. The study was performed on a long-term mature rat model. One hundred and five, three-month-old female Wistar rats were randomized into seven groups. One group was killed at the start of the study and was used as a baseline group. Three groups were ovariectomized and followed for one, three, or six months after the operation. Three groups were sham-operated and followed for the same periods. At death, three lumbar vertebrae were obtained from each rat, and changes in bone mass (ash content, trabecular bone volume (TBV)), bone structure, and biomechanical competence were assessed from these vertebrae. The results revealed an age-related (three-nine months) increase in bone mass and biomechanical competence in the sham-operated control groups. In the ovariectomized groups, an age-related decrease in TBV was disclosed. The ash content remained constant, whereas the biomechanical parameters--after an initial increase--showed decreasing values with age in the ovariectomized groups. When age-matched control and ovariectomized rats were compared, an increasing difference in both bone mass and bone biomechanical competence was disclosed. The study has shown that ovariectomy has a pronounced effect not only on vertebral bone mass, but also on bone quality, and that this mature rat model forms an excellent basis for evaluating potential therapeutic regimens for the treatment of osteoporosis.

Aging↗

PubMed1992

Long-term effect of orchidectomy on cortical bone from rat femur: bone mass and mechanical properties.

The study comprised seven groups of intact rats killed at 9, 12, 15, and 24 months of age, and three groups of rats castrated at the age of 9 months and killed together with the intact rats 3, 6, and 15 months after castration. The composition, dimension, and mechanical properties of intact bone as well as the constituent bone collagen from femoral diaphyses were investigated in relation to both age (9-24 months) and castration. Castration had no effect on density and only minor effect on ash and collagen contents. An age-related increase in bone mass, cross-sectional area, and wall thickness of the diaphyses was arrested (bone mass, area) or even reversed (to a decrease in wall thickness) after castration. Therefore, a growing difference, pronounced from 6 months after castration, between intact and castrated rats was observed in bone mass, cross-sectional area, and wall thickness. The compressive mechanical strength of intact bone normalized with regard to cross-sectional area was unaffected by castration, whereas castration tended to increase the stiffness of the bone collagen. When observed in a polarization microscope, two different zones in cross sections of the diaphyses were apparent. The average diameter of the border line separating the two zones was independent of age and castration. By measuring the average thickness of each of the two zones, age-related periosteal bone formation and endosteal bone resorption were demonstrated. After castration, the rate of bone formation was reduced and the rate of bone resorption was accelerated. Castration was thus found to affect the composition and the quality of the cortical bone to a minor extent only.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1991

The anabolic effects of human parathyroid hormone (hPTH) on rat vertebral body mass are also reflected in the quality of bone, assessed by biomechanical testing: a comparison study between hPTH-(1-34) and hPTH-(1-84).

PTH has a proven anabolic effect on bone mass, as has been shown in several animal models and treatment regimens. The aim of this study was to ascertain whether the positive effect on bone mass is also reflected in the quality of bone formed. The study was performed in a rat model using human PTH (hPTH). One hundred and twenty male Wistar rats, divided into 10 groups, were given either hPTH-(1-34) or hPTH-(1-84) in daily sc doses. Dose levels ranged from 0.11-3.00 nmol/100 g BW.day for a period of 30 days. At death all six lumbar vertebrae were obtained from each rat. A combination of methods was applied to these vertebral bodies in order to ascertain the effect of hPTH on vertebral bone volume, density, trabecular structure, and biomechanical competence. The results revealed a dose-dependent increase in total volume, dry weight, ash weight, and trabecular bone volume. Also, a dose-dependent increase in load values could be demonstrated. The increase in bone strength remained significant after normalization for both cross-sectional area and bone mass. This indicates that the increase in bone size and bone mass was not achieved at the expense of the quality of the bone present. When the two treatments were administered at the same molar dose level, no difference between hPTH-(1-34) and hPTH-(1-84) was revealed. On the basis of this study, it is concluded that PTH could prove to be a promising treatment in the management of osteopenic states.

Animals↗

PubMed1991

Influence of bilateral oophorectomy and estrogen substitution on the striated anal sphincter in adult female rats.

A quantitative histologic analysis of the striated anal sphincter of 24-month-old virgin female rats was performed to evaluate the effect of oophorectomy and estrogen substitution. The oophorectomized rats had a 21% (11-31%, 95% confidence limits) reduction in the cross-sectional area of the striated muscle tissue compared with controls. This was due to a reduction in the mean cross-sectional area of the muscle fiber, whereas the number of fibers was unchanged. Although the relative amount of stromal tissue was increased in the oophorectomized rats, the total stromal tissue was unchanged. No difference in the cross-sectional area of muscle tissue was found between the estrogen-substituted, oophorectomized rats and controls. This indicates that the estrogen depletion in the oophorectomized rats has induced the reduction in muscle tissue in the striated anal sphincter.

Anal Canal↗

PubMed1991

Age-related changes in the striated anal sphincter in female rats. A quantitative morphometric study.

A quantitative histologic analysis of the striated anal sphincter of virgin female rats aged 2 months and 24 months was performed to evaluate age-related changes. A 27% (8% to 46%, 95% confidence limits) increase in the cross-sectional area of the muscle in the older rats was observed compared with the young. This was due to an increase in both muscle and connective tissue. There was hypertrophy of both the small and large muscle fibres without change in the number with age. No evidence of age-related degenerative changes in this muscle in the virgin female rat was found.

Aging↗

PubMed1990

Age-related thermal stability and susceptibility to proteolysis of rat bone collagen.

The shrinkage temperature (Ts) and the pepsin-solubilizability of collagen fibrils in bone matrix obtained from decalcified femur diaphysis from 2-, 5-, 15- and 25-month-old rats were found to decrease with age. Digestion with human fibroblast collagenase dissolved less than half of the collagen, whereas sequential treatment by pepsin followed by collagenase resulted in its complete dissolution. This result shows that collagenase and a telopeptide-cleaving enzyme, when acting in an appropriate sequence, have a great potential for the degradation of bone collagen. The 'melting' profile of the pepsin-solubilized collagen showed a biphasic transition with transition peak at 35.9 degrees C and 40.8 degrees C. With increasing age an increasing proportion of the collagen 'melted' in the transition peak at 35.9 degrees C (pre-transition), and the 'melting' temperature (Tm) of the collagen decreased in parallel with Ts in relation to age. Both Ts and Tm decreased by 3 degrees C in the age span investigated. The age-related change in Ts could therefore be accounted for by the decrease in molecular stability. The collagenase-cleavage products of the bone collagen obtained by the sequential treatment with pepsin and collagenase showed only one peak transition (at 35.1 degrees C), and the Tm for the products was independent of age. The results indicate that the pre-transition for the pepsin-solubilized collagen is due to an age-related decrease in thermal stability may have implications for the mechanical strength and turnover of the bone collagen. In contrast with bone collagen, soft-tissue collagen showed neither the age-dependency of thermal stability nor the characteristic biphasic 'melting' profile.

Aging↗

PubMed1990

Long-term observation of the detrusor smooth muscle in rats. Its relationship to ovariectomy and estrogen treatment.

We studied the bladders of 24-month-old intact rats, rats that had been ovariectomized at the age of 6 months, and intact and ovariectomized rats treated by estrogen from the age of 16 months. The study thus comprized four groups: group I: bilaterally ovariectomized rats; group II: intact rats; group III: ovariectomized rats treated with estrogen; group IV: intact rats treated with estrogen. The weight and collagen concentration of the bladders were determined. The ovariectomized bladders weighed significantly less and had a higher collagen concentration than the intact bladders. Estrogen substitution for ovariectomized rats reversed these parameters. Detrusor strips were also used for organ bath studies. All bladders were similar in regard to the nerve-mediated frequency-response relationship. The atropine-resistant response was studied by adding scopolamine to the organ bath. Strips from ovariectomized rats had a significantly diminished atropine-resistant response, which was abolished by estrogen substitution. The present study suggests that micturition problems in menopause might have a structural as well as a pharmacological explanation.

Animals↗

PubMed1988

A study of the interaction in vitro between type I collagen and a small dermatan sulphate proteoglycan.

The interaction between a small dermatan sulphate proteoglycan isolated from human uterine cervix and collagen type I from human and rat skin was investigated by collagen-fibrillogenesis experiments. Collagen fibrillogenesis was initiated by elevation of temperature and pH after addition of proteoglycan, chondroitinase-digested proteoglycan or isolated side chains, and monitored by turbidimetry. Collagen-associated and unbound proteoglycan was determined by enzyme-linked immunosorbent assay after aggregation was complete. (1) The binding of proteoglycan to collagen could be explained by the presence of two mutually non-interacting binding sites, with Ka1 = 1.3 x 10(8) M-1 and Ka2 = 1.3 x 10(6) M-1. The number of binding sites per tropocollagen molecule was n1 = 0.11 and n2 = 1.1. The 0.1 high-affinity binding site per tropocollagen molecule indicates that the strong interaction between proteoglycan and collagen results from a concerted action of tropocollagen molecules in fibrils. Digestion of the proteoglycan with chondroitinase ABC did not affect these binding characteristics. (2) Proteoglycan did not affect the rate of fibrillogenesis, but increased the steady-state A400 by up to 90%. This increase was directly proportional to the saturation of the high-affinity type of binding sites. Neither isolated core protein nor isolated side chains induced a similar high increase in steady-state A400. (3) Electron micrographs showed that the fibril diameter was affected only to a minor extent, if at all, by the proteoglycan, whereas bundles of laterally aligned fibrils were common in the presence of proteoglycan. (4) Results obtained with human and rat collagen were similar.

Animals↗

PubMed1988

Mechanical properties of rat tail tendon in relation to proximal-distal sampling position and age.

The mechanical properties of 3, 15 and 25 month-old rat tail tendons were investigated in relation to proximal-distal sampling location along the fibre length. For the 15 and 25 month-old tendons maximum load as well as collagen content per mm fibre length (unit collagen) increased markedly from the proximal to the distal location. A linear regression analysis of the collagen content and mechanical parameters (maximum load, maximum slope of the load-strain curve and energy absorption) showed that these parameters were linearly correlated to the collagen content. However, normalization of the mechanical parameters with regard to the collagen content did not cancel the dependency of the parameters on proximal-distal sampling location. Normalized load and energy values for the 3 month-old tendons and normalized slope values for the 15 and 25 month-old tendons were found to decrease from proximal to distal location. These findings showed that tail tendons are heterogeneous along their length in respect to mechanical strength. The regression analysis also indicated the existence of an inverse relationship between unit collagen and mechanical quality of the collagen. Alternatively, the mechanical properties of tendon fibres might be influenced by other components than collagen.

Age Factors↗

PubMed1988

The influence of non-enzymatic glycosylation and formation of fluorescent reaction products on the mechanical properties of rat tail tendons.

Mechanical stability was examined in rat tail tendons after in vitro incubation in glucose at pH 7.4 using buffer systems of either phosphate or tris(hydroxymethyl)aminomethan. In the phosphate buffer system glucose and fluorescent compounds were found to be attached to the collagen molecules and the maximum 'stress' of the tendons was increased. In the tris(hydroxymethyl)aminomethan buffer system glucose was attached to the collagen molecules, but only small amounts of fluorescent compounds were attached to the collagen molecules and no changes in mechanical parameters were recorded. Initial incubation of tendons in a high concentration of glucose followed by incubation in either phosphate or tris(hydroxymethyl)aminomethan buffer solutions resulted in equal attachment of glucose to the collagen, but only the collagen reincubated in phosphate buffer developed a relatively high amount of fluorescent compounds and an increase in maximum mechanical 'stress' compared to the collagen reincubated in tris(hydroxymethyl)aminomethan buffer. This shows that the non-enzymatic glycosylation per se does not necessarily influence the mechanical properties of collagen. Additional reactions like transformation of glucose into fluorescent compounds or browning reaction products by Maillard's reaction seem to be essential.

Animals↗

PubMed1987

Thermal stability of human-fibroblast-collagenase-cleavage products of type-I and type-III collagens.

Rat skin type-I and type-III collagens were degraded by human fibroblast collagenase at a temperature below the 'melting' temperature for the two resulting fragments, namely the N-terminal three-fourths, TCA, and the C-terminal one-fourth, TCB. The specific cleavage of the collagen was confirmed by electrophoresis and determination of molecular length by electron microscopy. The two fragments were separated by gel filtration and the thermal stabilities of the isolated fragments were determined. For type-I collagen, the 'melting' temperatures of the two fragments were found to differ by only 0.5 degrees C and were 4.5-5.0 degrees C below that of the uncleaved molecule. The 'melting' temperatures of the uncleaved molecule and the N-terminal fragment were independent of the extent of N-terminal intramolecular cross-linking. For type-III collagen, the 'melting' temperatures of the fragments were found to differ by 1.3 degrees C. The small fragments of the two types of collagen 'melted' at the same temperature, whereas the large type-III fragment 'melted' at a slightly higher temperature than did the large type-I fragment. Reduction of the disulphide bonds located in the C-terminal type-III fragment did not affect the thermal stability of this fragment. The thermal stability of uncleaved type-III collagen was found to be variable, but the reason for this is not known at present.

Animals↗

PubMed1987

Mechanical properties of native and reconstituted rat tail tendon collagen upon maturation in vitro.

Native and reconstituted rat tail tendon collagen were tested mechanically after in vitro maturation by incubation. The mechanical strength of the native tendons increased upon incubation and attained maximum strength values similar to those of tendons matured and aged in vivo. This finding indicates that the same stabilizing process occurs both in vivo and in vitro. However, the mechanical strength values similar to those of tendons matured and aged in vivo. This finding indicates that the same stabilizing process occurs both in vivo and in vitro. However, the mechanical strength increased at an initial higher rate in vitro than in vivo. The mechanical strength of fibrils reconstituted from purified tail tendon collagen increased during incubation in air as previously reported for fibrils prepared from skin collagen. Fibrils prepared from tail tendon and skin collagen shared common mechanical and thermal stability characteristics upon the incubation. However, distinct qualitative mechanical characteristics for fibrils of the two collagens were found. These characteristics showed a resemblance to those of the respective source tissues. The results indicate that the same process is responsible for the gain in mechanical strength of native tissues and reconstituted collagen fibrils. Thus, reconstituted collagen fibrils seem a useful model for studying mechanical stability changes during maturation of collagen.

Aging↗

PubMed1987

Biomechanical competence of vertebral trabecular bone in relation to ash density and age in normal individuals.

Cylindrical trabecular bone samples from the central part of the first lumbar vertebral body were obtained from 42 normal people (27 females and 15 males) aged 15-87 years and analyzed by a compression test in either vertical or horizontal direction. Maximum stress, maximum stiffness, energy absorption capacity, and strain at maximum stress (compressibility) were calculated from the load-deformation curves. The ash density of the samples was measured after incineration. From age 20 to 80 years, the decline (P less than 0.01) in ash density was 48-50% compared to a 75-80% decrease (P less than 0.001) in vertical stress, stiffness, and energy absorption capacity. Qualitatively similar age-related changes (P less than 0.01) were observed by horizontal compression, but the absolute values were smaller. In both directions, highly significant positive correlations (P less than 0.01) were observed between the biomechanical properties and ash density stress, stiffness and energy absorption capacity still showed significant decreases with age (P less than 0.01). The vertical maximum strain values, which increased (P less than 0.05) with age, were inversely related to the other biomechanical variables (P less than 0.05) and to the ash density (P less than 0.05). It is concluded from the study that the biomechanical competence of vertebral trabecular bone depends not only on bone mass (ash density) but also on the continuity of the trabecular lattice, which changes with increasing age.

Adolescent↗