Loss of cilia causes embryonic lung hypoplasia,liver fibrosis,and cholestasis in the talpid3 ciliopathy mutant

Sonic hedgehog plays an essential role in maintaining hepatoblasts in a proliferative non-differentiating state during embryogenesis. Transduction of the Hedgehog signaling pathway is dependent on the presence of functional primary cilia and hepatoblasts, therefore, must require primary cilia for normal function. In congenital syndromes in which cilia are absent or non-functional (ciliopathies) hepatorenal fibrocystic disease is common and primarily characterized by ductal plate malformations which underlie the formation of liver cysts, as well as less commonly, by hepatic fibrosis, although a role for abnormal Hedgehog signal transduction has not been implicated in these phenotypes. We have examined liver, lung and rib development in the talpid³ chicken mutant, a ciliopathy model in which abnormal Hedgehog signaling is well characterized. We find that the talpid³ phenotype closely models that of human short-rib polydactyly syndromes which are caused by the loss of cilia, and exhibit hypoplastic lungs and liver failure. Through an analysis of liver and lung development in the talpid³ chicken, we propose that cilia in the liver are essential for the transduction of Hedgehog signaling during hepatic development. The talpid³ chicken represents a useful resource in furthering our understanding of the pathology of ciliopathies beyond the treatment of thoracic insufficiency as well as generating insights into the role Hedgehog signaling in hepatic development.     

Subadult stress,morbidity, and longevity in Latte Period populations on Guam,Mariana Islands

The frequency and age distribution of linear enamel hypoplasia (LEH) in the dentition of 293 individuals from Latte Period sites (AD 800–1521) on Guam, Mariana Islands, are examined in this study. Individuals dying as subadults (before age 16) and as young adults (ages 16–21) have more frequent LEHs than those who survived to middle or late adulthood, documenting a relationship between LEH-causing stress events and reduced life expectancy. The age distributions of cribra orbitalia and skeletal infection in children who died by age 10 exhibit striking similarities to the etiological age patterns of LEH in children, and those with skeletal infection have more frequent hypoplasias than children without infection. The comorbidity of systemic stress and infection in children, and their impact on life expectancy, are interpreted in the biocultural context of high population density in the large coastal villages of the late prehistoric period in the Marianas. Am J Phys Anthropol 104:363–380, 1997. © 1997 Wiley-Liss, Inc.     

Observations of dental diseases among prehistoric populations of Hungary

The incidence of dental disease among people in developing countries today raises questions about the variation in the oral health of prehistoric populations. Considering these questions, we offer observations describing several types of dental disease which occurred among certain prehistoric populations of Hungary. The dental remains of 162 individuals recovered from seven sites of the Neolithic, Copper, and Bronze Age periods were examined for evidence of caries, hypoplasia, and periodontal disease. Appropriate methods were used to describe and record these dental lesions. The incidence of dental caries was low by comparison to other prehistoric agriculturists except for two forms of root caries: cervical and cemental. These types accounted for 68% of all the carious teeth recorded. Enamel hypoplasia was also lower than expected, occurring on only 4% of the total number of teeth. Periodontal abscesses were rare but other milder forms of periodontal lesions were frequent. Alveolar bone resorption occurred in varying degrees and followed the expected age distribution. The few exceptions were children or adolescents whose crania had other lesions suggesting a mineral metabolic disturbance. The lower incidence of enamel caries is likely due to high fluoride ingestion which also may have influenced the expression of enamel hypoplasia. No clear population trends were seen in dental disease incidence except for cemental caries which were found among Copper and Bronze Age remains.     

The chronological distribution of enamel hypoplasias from prehistoric Dickson Mounds populations

The chronological distributions of enamel hypoplasias (indicators of nonspecific stress) are assessed for 111 individuals from two prehistoric populations from Dickson Mounds, Lewiston, Illinois. The earlier population (circa A.D. 950-1150) involves a transition from an indigenous gathering-hunting tradition to increasing adoption of Mississippian lifeways. The later population (circa A.D. 1150-1300) is fully Mississippian (MM). Based on the occurrence of hypoplasias on all permanent teeth except third molars, 14 half-year periods from birth to 7.0 years are graded for evidence of hypoplasia-stress. Both populations have a low frequency of hypoplasia which occur before 2 years of age and after 4 years of age. A common peak frequency of hypoplasias between 2.0 and 4.0 years is suggestive of an elevated degree of stress at weaning. The peak frequency of hypoplasias is earlier in the MM (2.5-3.0 years versus 3.0-3.5 years in the pre-Mississippian population). In addition, the rise to and decline from peak frequency occurs approximately 0.5 years earlier in the MM. The earlier and sharper rise to peak frequency suggests earlier and more severe weanling-related stress. Hypoplasias chronologies are undoubtedly influenced by age-related host resistance factors (Sarnat and Schour, 1941). Nevertheless, these data demonstrate that populations may vary in their chronological distribution of hypoplasias and that these variations may provide useful information on age-related patterns of exposure to environmental stressors.     

Enamel hypoplasia in sympatric chimpanzee and gorilla

The prevalence of enamel hypoplasia in 229Pan andGorilla, from the Republic of Cameroon, is described. A substantially higher proportion of gorillas (76%) than chimpanzees (58%) was affected. The incidence of enamel hypoplasia was not a function of sex, body size, or pathology. A study of tooth formation, from radiographs of a further series of immature apes, indicated that the mandibular canine bore 99% of all information about hypoplasia events. In both species a marked regularity of hypoplastic grooving with an interval of about 11.4% of canine crown height was observed. This appears to reflect a semi-annual cycle of stress which is tentatively linked to the twice-yearly rainy season. Uniform spacing of hypoplastic grooves has been observed in a variety of fossil hominids. Readily observable hypoplastic time markers in the teeth have potential for disclosing growth rates in early Hominidae. This is considered important because of the profound significance which prolonged maturation and longevity characteristic of recent human beings have for the transmission of learned behavior and social bonding.     

Cyclic Nucleotides and the Activity of Glia Maturation Factor in the Hypoplastic Cerebellum of Developing Jaundiced Gunn Rats

Developmental changes of cyclic nucleotides were studied in the hypoplastic cerebellum of jaundiced Gunn rats over the period of postnatal days 8 to 30. The mitogenic activity of glia maturation factor was also measured at day 15. In jaundiced homozygotes (jj), the amount of cyclic GMP on a protein basis was not significantly different from that in control heterozygotes (j+) at either day 8 or 15, but at day 30 it was reduced to about 19% of the control. On the other hand, a lowered nucleotide level on a wet weight basis in jj rats was already statistically significant at day 15. In contrast to cyclic GMP, the rates of increase of cyclic AMP on a wet weight basis were almost the same in the two groups of rats, but the nucleotide levels on a protein basis at days 15 and 30 were a little, but significantly, higher in jj rats than in j+ rats. The activity of glia maturation factor in jj rats was found to be 1.5-3 times as high as that in j+ rats. Possible implications of the present results are discussed.     

Different Behaviors Among Lysosomal Enzymes in the Cerebellum of Jaundiced Gunn Rats with Cerebellar Hypoplasia

Activities of six lysosomal enzymes in the cerebellum of jaundiced homozygous (jj) Gunn rats were examined from 5 to 20 days of life and compared with those in heterozygotes (j+). Significantly higher enzyme activities were first detected at 8 days. The jj/j+ activity ratios of all enzymes peaked at 15 days. The ratios of beta-glycerophosphatase, beta-mannosidase, and acid lipase were only 1.3-1.7, whereas those of arylsulfatase and cathepsin were 2.0 and 3.1, respectively. The most striking increase in activity was observed with beta-glucuronidase, the ratio of which was 8.4. These results indicate a selective increase in activities of certain lysosomal enzymes in the hypoplastic cerebellum of jj rats.     

Hominid enamel thickness: I. The Krapina Neandertals

Dental x-rays were taken of isolated and in situ adult molar teeth of the Krapina Neandertal (n = 63) and of recent and contemporary molars (n = 423). The radiographs were digitized at high resolution (1,024 × 1,520 × 8 bits) with a 35 mm solid state scanner. Ratios of enamel cap area to the underlying dentinal-pulpal area were determined and comparisons were made between average ratios for the Neandertal and contemporary molars. Neandertal molars had significantly smaller ratios than did contemporary teeth (P < 0.05). It is suggested that the smaller ratios represent relatively thinner enamel for Neandertals and that the thin enamel may have been caused by a metabolic depression that resulted in reduced enamel quantity (hypoplasia). Alternately, the observed differences may be related to expanded pulps seen in various stages of taurodontism. © 1993 Wiley-Liss, Inc.     

禄丰古猿带状牙釉质发育不全的再观察

牙釉质发育不全是反映牙齿发育过程中遭遇生理性刺激的有效指标。本文对来自云南禄丰石灰坝的禄丰古猿(Lufengpithecus lufengensis)261枚单颗恒齿进行观察分析,发现223枚牙齿普遍罹患带状牙釉质发育不全(LEH),比例为85.4%,高于其它已报道过的中新世古猿、化石人科成员及现生大猿。另一方面,用扫描电镜和数码显微镜着重分析了12枚犬齿,均有多条LEH,且雄性犬齿的LEH条数多于雌性;相邻LEH间的釉面横纹数在14-25条之间。结合禄丰古猿釉面横纹的生长周期(9天),估算相邻LEH之间的时间间隔为4.8-6.6月,季节性营养不良可能是禄丰古猿釉质发育不全的主要原因。