bluuebunny/crossref_metadata_2025 huggingface dataset:
A form of sensorineural deafness is determined by a mitochondrial and an autosomal locus: Evidence from pedigree segregation analysis
Authors: Bu Xiangdong , Shohat Mordechai , Jaber Lutfi , Rotter Jerome I.
Published: June 2005

We have previously reported a large Israili‐Arab pedigree with sensorineural deafness possibly determined simultaneously by two loci‐one mitochondrial, and one autosomal recessive. This was analyzed by extending classic segregation analysis methods to the many nuclear families derived from the maternal line pedigree. Here we expand this pedigree and extend our analysis by using the regressive models for segregation analysis on the entire pedigree. The corresponding REGD computer program was utilized and the marrying‐in males' and paternal line members' affection statuses were assigned as unknown to accommodate the exclusive maternal transmission pattern. For the autosomal locus, a simple autosomal recessive (q = 0.52) model with a nearly complete penetrance (0.93) was found to be the regressive models to test the hypothesis of mitochondrial mutation occurred in a heteroplasmic distribution in the family members, this could not explain the familial aggregation in this pedigree, and an autosomal recessive locus is still required. These results provide further support for the concept that the sensorineural deafness occurring in this large Israeli‐Arab pedigree results from simultaneous involvement of two genes at two different loci, one mitochondrial and likely homoplasmic, and the other autosomal and recessive. © 1993 Wiley‐Liss. Inc.
Cigarette smoking and trisomy 21 at amniocentesis
Authors: Kline Jennie , Levin Bruce , Stein Zena , Warburton Dorothy , Hindin Rita
Published: June 2005

Several studies raise the possibility that smoking during pregnancy is associated with a slightly decreased odds of trisomy 21 at birth. If it is, associations may reflect decreased incidence at conception, increased intrauterine loss (at one or several times in gestation), or both. Women ( n = 13,729) undergoing prenatal diagnosis completed a questionnaire before learning karyotype results. For each women with a trisomy, up to 4 controls with chromosomally normal pregnancies, matched for age and hospital, were selected. Analyses drew on the 89 trisomy 21‐control matched m‐tuples in which diagnosis was by amniocentesis at 14‐26 weeks. We compared the odds of smoking at last menstrual period and in the past in cases and controls. The odds of current smoking versus never smoking were decreased [adjusted odds ratio = 0.8, 95% confidence interval (CI) 0.4‐1.6]; and the odds of exsmoking increased (adjusted odds ratio = 1.4, 95% CI 0.9‐2.4) in trisomy 21 cases. The association with current smoking was essentially unchanged when the unexposed reference group was defined as exsmokers and women who never smoked (adjusted odds ratio = 0.7, 95% CI 0.4‐1.4). These results for current smoking agree well with a summary estimate based on combined studies of births. One interpretation is that at amniocentesis, as has been reported for births, current smoking is associated with a slightly decreased odds of trisomy 21. If associations at amniocentesis and birth are of equal magnitude, the explanation that observations at birth reflect increased loss in the second half of pregnancy with current smoking is unlikely to be correct. However, the present amniocentesis evidence supports this interpretation weakly and is insufficient to rule out the null hypothesis that smoking is unrelated to trisomy 21. © 1993 Wiley‐Liss. Inc.
Estimating age at onset distributions: The bias from prevalent cases and its impact on risk estimation
Authors: Chen Wei J. , Faraone Stephen V. , John Orav E. , Tsuang Ming T.
Published: June 2005

Since many disorders have a variable age at onset, knowing the age at onset distribution of a disease facilitates epidemiologic analyses in several ways. The age at onset distribution is commonly used to estimate morbidity risks or the recurrence risks in genetic counseling. Unfortunately, estimation of a disease's age at onset distribution is not straightforward. The observed age at onset distribution obtained from prevalent cases is usually used in these epidemiologic analyses. Through simulation studies, we show that, in certain situations, the observed age at onset distribution has a non‐negligible downward bias. This bias can lead to a substantial underestimation of the morbidity risk or the recurrence risk. The simulations also demonstrate that a non‐parametric approach for correcting the age at onset distribution works well even when mortality increases after onset. The results have implications for diseases that have adult onset and/or increased mortality after onset. We suggest that researchers should use corrected age at onset distributions, rather than relying on observed distributions, in the calculation of either morbidity risks or recurrence risks. © 1993 Wiley‐Liss. Inc.
Distribution of the admixture test for the detection of linkage under heterogeneity
Authors: Faraway Julian J.
Published: June 2005

The admixture test for the detection of linkage under heterogeneity is considered. We show that the null distribution of this test statistic has half its weight concentrated on zero and the other half on a complicated distribution that can be approximated by max (X1, X 2 ) where X1 and X2 are independent χ variables. We also investigate the stability of the size of the test for small samples. The power of this test to detect linkage, when heterogeneity is present, can be substantially greater than the standard test that assumes homogeneity. Even when heterogeneity is not present, the test is only slightly less powerful than the homogeneous test. This would suggest the use of the admixture test in preference to the homogeneous test if the presence of heterogeneity is at all suspected. © 1993 Wiley‐Liss. Inc.
Familial clustering of colon, breast, uterine, and ovarian cancers as assessed by family history
Authors: Nelson Christine L. , Sellers Thomas A. , Rich Stephen S. , Potter John D. , McGovern Paul G. , Kushi Lawrence H.
Published: June 2005

The aggregation of colon, endometrial, ovarian, and possibly breast cancers in families has been described as a “cancer family syndrome” (now called Lynch syndrome II). To determine if the familial clustering of these malignancies was more common in women with cancer than without, we analyzed data from the Iowa Women's Health Study (IWHS), a population‐based sample of 41,837 women aged 55–69 years. Self‐reported information was collected on history of colon, uterine, ovarian, and breast cancers in female first‐degree relatives. A family history of cancer of the breast (odds ratio [OR] = 1.4), colon (OR = 1.3), and uterus (OR = 1.3), but not ovary (OR = 1.2), was significantly more common among women with a personal history of any of these four cancers (all P < 0.05); the pattern of the ORs suggested strongly that the clustering tended to be site‐specific. Age‐adjusted relative risks (RR) of incident colon cancer over 5 years of follow‐up (N = 237) were calculated with regard to family history. Colon cancer incidence was increased among women with a family history of breast (RR = l.3), uterine (RR = 1.4), colon (RR = l.5), and ovarian (RR = 1.3) cancers, although none of the risk estimates achieved statistical significance. RR was, however, significantly related to the number of different cancer sites reported among family members (Ptrend = 0.008). These data on a representative sample of postmenopausal women suggest that family histories of colon, breast, uterine, and ovarian cancers are associated with an increased risk of cancer at the same site, but provide little support for the hypothesis that Lynch syndrome II is a non‐random occurrence. © 1993 Wiley‐Liss, Inc.
The Seattle Alzheimer's disease data set
Authors: Wijsman Ellen M. , Bird Thomas D. , Martin George M. , Schellenberg Gerard D.
Published: June 2005

Forty families submitted to Genetic Analysis Workshop 8 are described. These are the families in the Seattle data set which have been typed for at least one genetic marker from the centromeric region of chromosome 21 or the q arm of chromosome 19. Thirteen of these families have average ages of onset below age 61 and are therefore considered to be early onset families. Seven of the families are of Volga German descent. Thirty‐four of the families have autopsy documented Alzheimer's disease, including all 13 of the early onset pedigrees. The data set includes both the clinical and pedigree information available on the portions of the pedigrees used in the linkage analyses, genotype data on three loci on chromosome 19 and four loci on chromosome 21, and more extended family data on individuals who have not been included in the linkage analyses. © 1993 Wiley‐Liss, Inc.
Susceptibility genes for familial Alzheimer's disease on chromosomes 19 and 21: A reality check
Authors: Farrer Lindsay A. , Stice Ligaya
Published: June 2005

Linkage data from 92 FAD kindreds were analyzed by lod score analysis under various assumptions of disease penetrance, marker allele frequencies, and heterogeneity. Multilocus linkage analysis supports the existence of a gene in 40%–65% of families with predominantly late‐onset illness (after age 65) on chromosome 19 between D19S13 and ATP1A3. Evidence for a second FAD gene on chromosome 21 is weaker and stems primarily from a few families with early‐onset disease. Our findings also indicate that choice of the genetic model for FAD and marker allele frequencies may be crucial to conclusions about linkage and heterogeneity. © 1993 Wiley‐Liss, Inc.
Linkage of Alzheimer's disease to chromosome 21 and chromosome 19 markers: Effect of age of onset assumptions
Authors: Goldin L. R. , Gershon E. S.
Published: June 2005

Age of onset heterogeneity in Alzheimer's disease families was modelled by allowing for different liability classes for affected individuals according to their age of onset when calculating lod scores to chromosome 21 and chromosome 19 markers. Linkage to chromosome 21 was supported in the Boston data set, and the method of age correction did not greatly change the lod scores when only affected individuals were analyzed. The location of a gene on chromosome 19 for late age of onset illness was affected by the assumptions about early onset individuals. © 1993 Wiley‐Liss, Inc.

This article is a US Government work and, as such, is in the public domain in the United States of America.
Risk factors for atherosclerosis in twins
Authors: Duffy David L. , O'Connell Dianne L. , Heller Richard F. , Martin Nicholas G.
Published: June 2005

We performed multivariate genetic analyses of cardiovascular risk factors from two sets of data on US and Australian female twins. Similar models for body‐mass index (BMI), serum low density (LDL) and high density (HDL) lipoproteins, including age as a covariate, were fitted successfully to both groups. These suggested that BMI, or genes responsible for a significant proportion of the variance of BMI, explained correlations between lipid subfractions, as well as those between blood pressure and lipid subfractions, especially HDL. © 1993 Wiley‐Liss, Inc.
Multivariate genetic analysis of apo AI concentration and HDL subfractions: Evidence for major locus pleiotropy
Authors: Blangero J. , Williams‐Blangero S. , Mahaney M. C.
Published: June 2005

A major locus influencing apolipoprotein AI (apo AI) serum levels was detected using data from the Donner Laboratory Family Study. This locus accounts for 46% of the phenotypic variability in apo AI levels. Multivariate segregation analysis revealed that this major locus also has significant pleiotropic effects on the relative distribution of high density lipoproteins. © 1993 Wiley‐Liss, Inc.
Segregation analysis for high density lipoprotein in the berkeley data
Authors: Cupples L. Adrienne , Myers Richard H.
Published: June 2005

Transmission models for high density lipoprotein (HDL) were evaluated in the Berkeley data set through segregation analyses using S.A.G.E. These preliminary analyses indicate that among the models fitted, an additive model with non‐Mendelian transmission probabilities provides a good fit for HDL, suggesting the possibility of a significant environmental component in the transmission of HDL. After adjustment for triglyceride, however, Mendelian models for a major gene seem to provide as good a fit as non‐Mendelian models but the results do not permit distinction between a dominant model and an additive model. © 1993 Wiley‐Liss, Inc.
A comparison of univariate and multivariate tests for genetic linkage
Authors: Amos C. I. , Laing A. E.
Published: June 2005

A variety of robust and model‐dependent genetic linkage methods were applied to log transformed lipid levels from a large pedigree in which the LDL receptor defect has been shown to segregate by molecular biologic techniques. Application of the Haseman‐Elston and a variance‐components based test for linkage identified LDL and cholesterol as cosegregating with the marker C3, which is genetically linked to the LDL receptor defect. Consideration of lipid fractions as a multivariate response identified (0.723 × cholesterol) ‐ (0.551 × triglycerides) as most strongly supporting evidence for linkage with C3. Subsequent segregation and linkage analyses provided support for an autosomal dominant major gene influencing either LDL or the function of cholesterol and triglycerides. Genetic linkage to LDL was only mildly supported, with a maximum lod score of 0.51 at a recombination fraction of θ = 0.33. Genetic linkage of the linear function to C3 was more strongly supported, with a maximum lod score of 1.69 at θ = 0.09. Bivariate analysis of clinical affection (with either type IIa or type IIb hyperlipidemia) and quantitative measures (LDL or the linear function) generally led to decreased lod scores, indicating, in this pedigree, loss of information when using clinical affection. © 1993 Wiley‐Liss, Inc.
Monte Carlo analysis on a large pedigree
Authors: Thompson E. A. , Lin S. , Olshen A. B. , Wijsman E. M.
Published: June 2005

Monte Carlo methods for linkage and segregation analysis are applied to the HGAR1 pedigree. To address these data, the methods are extended in several ways. The results are compared with those provided by PAP. © 1993 Wiley‐Liss, Inc.
Aggregation in vivo of Dissociated Cells: II. Role of developmental age in tissue reconstruction
Authors: Garber Beatrice
Published: June 2005

Dissociated skin cells from 5‐ to 14‐day old chick embryos were placed on the chorioallantoic membrane of host embryos as a suspension or after preaggregation in vitro and were allowed to develop as grafts for 6–10 days. The capacity of cells from younger and older embryos to reconstruct feathers was examined and found to differ characteristically. Young cells, from 5‐ to 8‐day embryos (pre‐placodal and placodal feather stages), reconstructed normal feathers in advanced states of differentiation within large thin‐walled vesicles lined by unkeratinized epithelium. Cells of intermediate age, 10‐day old embryos (hump stage feathers), reconstructed feathers which showed typical histological differentiation into barb ridges and pulp, but were atypical in overall plan; skin epithelium was formed usually as compact keratinizing cysts, sometimes as thin unkeratinized linings of expanded vesicles. Cells from older skin, from 12‐ to 14‐day old embryos, did not reconstruct feathers, but, instead, formed extensive sheets of thick, stratified, keratinized epithelium associated with a dense dermal stroma.

These results indicate that cells dissociated from the dermal papilla at post‐placodal stages do not initiate de novo feather morphogenesis. This loss of capacity for feather reconstruction which accompanies advancing developmental age is discussed in terms of known epithelial‐mesenchymal interactions and is considered as a consequence of several possible events: (a) loss of inductiveness by the dermis, (b) loss of responsiveness by the epidermis, (c) loss of cell recognition in sorting out processes, (d) active suppression of sorting out or inductive interactions by conflicting concomitant developmental processes.
Quantitation of amylases in Drosophila separated by acrylamide gel electrophoresis
Authors: Doane Winifred W.
Published: June 2005

A technique was developed for the qualitative and quantitative analysis of amylases separated by disc electrophoresis. Gels in which separation occurred were incubated against a starch‐acrylamide film attached to a glass plate. This was subsequently stained with iodine, covered with another plate, and scanned with a densitometer. Enzyme activity as well as an impression of the gels were transferred to the film, thus providing a permanent record of both banding patterns and activity in each band without destroying the gels. A direct relationship was demonstrated between enzyme concentration and change in optical density of the substrate in the bands on the stained film. It was also shown that the amylases remaining in the gels were fully active following electrophoresis and incubation. They could then be cut out, eluted and used for further analysis.

The method was applied to extracts from individual adults of eight Amy strains of D. melanogaster, each characterized by a different amylase banding pattern. Patterns formed by separation in acrylamide gel were compared with those previously described for agar gel electrophoresis. Relative activity in each band of a given pattern was determined in addition to the actual activity, which was calculated in mg starch hydrolyzed/minute. Total activity, or the sum of the activities in all bands of a given genotypic pattern, was calculated for each fly. The results fell within the range of expected variability expressed by single flies of each genotype when subjected to standard methods of starch‐iodine assay.
Tissue dynamics of steady state growth in hydra littoralis. III. Behavior of specific cell types during tissue movements
Authors: Campbell Richard D.
Published: June 2005

Hydra tissues continuously move from the growing column to the body extremities. To study the cellular basis of these movements, mosaic hydra were produced by grafting portions of isotopically labeled animals to portions of unlabeled ones. The progressions of labeled cells away from the original graft site were determined by the method of radioautography. From the data obtained, it is possible to deduce the migratory relations between different cell types and the patterns of their movement.

Most cells move in the form of coherent expanding epithelia, in which cells do not individually wander relative to neighboring cells. The gastrodermal tissue sheet includes the gland and digestive cells; the epidermal tissue sheet includes the interstitial and epitheliomuscular cells. These tissues move distally and proximally from a “stationary region,” near the top of column. The two epithelia do not move at the same rate, however, and their stationary regions are at different column levels.

Nematocytes migrate in an amoeboid fashion from the body column to the tentacles. They migrate along the epidermal muscular layer, and do not move through the mesolamella to the gastrodermis. These aspects of cell behavior are consistent with the histological structure of hydra.
Combined action of fluorouracil and two mutant genes on limb development in the mouse
Authors: Dagg C. P.
Published: June 2005

The influence of a teratogen on the penetrance and expressivity of two mutant genes that affect limb development in mice was investigated. A low dose of the teratogen, 5‐fluorouracil, produced preaxially hyperphalangous hind feet in a large proportion of wild type fetuses when injected at ten days of development. A high dose increased the frequency of hyperphalangy, caused tibial hemimelia in many hyperphalangous fetuses, and produced cleft palate and vertebral deformities.

The mutations, luxoid and luxate, are autosomal semidominant genes that induce preaxially polydactylous hind feet in heterozygotes and tibial hemimelia in homozygotes. Other pleiotropic effects of luxoid in homozygotes are polydactylous forefeet, kinked tails, agenesis of the patella, and infertility in males. In luxate homozygotes the forefeet, tail and patella are normal but the fabella medialis, a sesamoid bone of the knee, is absent.

Wild type females were mated to heterozygous luxoid or luxate males and injected with the low dose of fluorouracil. Some of the treated offspring were allowed to be delivered and were subsequnently mated to determine their genotypes. Tibial hemimelia was found in some heterozygous luxoid and luxate offspring but not in wild type offspring, demonstrating a combined effect of gene and tertogen on limb development. The syndrome of fluorouracil‐induced hind limb defects in all heterozygous offspring resembled the syndrome normally found in untreated luxate homozygotes, and therefore, in luxoid heterozygotes the florouracil‐induced phenotype was atypical. Male infertility, polydactylous forefeet, kinked tails, cleft palate, and vertebral defects were not found in fluorouracil‐treated heterozygotes of either mutant.
Problems of acetazolamide and N‐ethylnicotinamide as teratogens
Authors: Landauer Walter , Wakasugi Noboru
Published: June 2005

Experiments with acetazolamide and N‐ethylnicotinamide were made by injection into the yolk sac of chicken eggs after 24 and 96 hours of incubation. Acetazolamide produced in both stages abnormalities of the upper beak, the dosage‐effect response following a linear course. Effects minor in incidence were rumplessness at 24 hours, bending of tibiotarsus shaft in both stages and muscular hypoplasia after 96 hours. N‐ethylnicotinamide led to abnormalities of the upper beak in both stages. to malformations of tibiotarsus and fibula at 96 hours. With increasing dosages the results of N‐ethylnicotinamide rose by threshold effects. In a particular strain of White Leghorn fowl embryos gave little or no response to acetazolamide; N‐ethylnicotinamide produced the usual incidence of long bone defects, but few beak abnormalities. Acetazolamide acted as protective supplement when added to treatment with sulfanilamide; it prevented all abnormalities (micromelia) of long bones; it reduced incidence of defects of upper and lower beak after treatment at 24 hours, but not those of upper beak after 96 hours. N‐ethylnicotinamide also gave complete protection against sulfanilamide‐induced abnormality of lower beak and long bones, but an increased incidence of shortened upper beak. Acetazolamide and N‐ethylnicotinamide injected together at 96 hours led to exaggeration in incidence and change in expressivity of defects of the upper beak and a drastic lowering in frequency of tibiotarsus‐fibula malformations. Supplements of ADP reduced toxicity of acetazolamide and incidence of defects of the upper beak produced by it. Interference with NAD functions and oxidative phosphorylation is likely to be the cause of the teratogenic effects of acetazolamide as well as N‐ethylnicotinamide.
The action of x‐irradiation on the regeneration field of the forelimb of the adult newt, Diemictylus viridescens,
Authors: Oberpriller Jean Colville
Published: June 2005

Studies were conducted in order to determine the nature of the action of x‐irradiation on regeneration of the urodele forelimb. Right and left forelimbs of adult newts were parabiosed along their posterior edges, after the right limbs had been irradiated with 2,000 r. Forelimbs of control animals underwent similar operations. However, both limbs remained unirradiated. The angles which the stumps made with each other were classified as parallel, acute, and wide angles. Sixty days after amputation of these limbs, the cartilage patterns of the two groups were compared. In the control series, as the angle between the stumps was increased, the number of digits in the bilaterally symmetrical regenerates decreased, with a loss of central structures. At very wide angles, the doubled stumps produced no regenerates. In the experimental series, there were no interference effects from the irradiated right forlimbs. Single normal asymmetric left hands regenerated, despite widening angles between the stumps. Sham operations, which were performed on irradiated and unirradiated limbs, seemed to have no effect on the regenerative capacities of the limbs, with no regeneration in 97.7% of the irradiated limbs and normal regeneration in 91.1% of the unirradiated limbs. X‐rays seem to act on the limb to eliminate the interference effects normally found in regenerating doubled stumps. This seems to involve a disruption of the longitudinal control of the regeneration field. The loss of inter‐tissue communication and possible loss of the bioelectric field is discussed.
The ear of the chameleon: Chamaeleo senegalensis and Chamaeleo quilensis
Authors: Wever Ernest Glen
Published: June 2005

The chameleon ear presents special problems because of variations of structure from the usual lizard pattern: there is no external ear opening and no visible tympanic membrane, and the round window of the cochlea is usually said to be lacking.

Measurements of auditory sensitivity in terms of the electrical potentials of the cochlea were carried out in two species, Chamaeleo senegalensis and Chamaeleo quilensis. The results indicated poor sensitivity in comparison with lizards in general, yet the performance was not far below that found in many species with conventional sound‐conducting systems. The frequency range extended from 100 to 10,000 cps, with the best sensitivity in the region of 200 to 600 cps.

Experiments were carried out to investigate the operation of these ears in response to aerial sounds and mechanical vibrations. The observations indicated that aerial sounds are received by a special surface, the pterygoid plate, embedded in the tissues at the side of the head. This system resembles that of snakes, in which a detached quadrate bone serves as a receptive surface.

The round window problem is not yet solved, but the suggestion is made that there is a path of pressure discharge from the scala tympani to the air of the middle ear cavity by a circuitous route, through the tympanic recess and a series of small spaces and blood vessels traversing the glossopharyngeal foramen. The frictional resistance of such a hindered pathway of discharge could account for the poor sensitivity of these chameleon ears.
Aggregation in vivo of dissociated cells. III. Effect of state of differentiation of cells on feather development in hybrid aggregates of embryonic mouse and chick skin cells
Authors: Garber B. , Kollar E. J. , Moscona A. A.
Published: June 2005

The relation of embryonic age and state of differentiation of cells to their capacity to reconstruct integumental tissues was studied in aggregates of cells dissociated from the skin of 13‐ to 15‐day mouse and 8‐day chick embryos. To attain advanced morphogenesis of the reaggregates, cell suspensions were placed and aggregated on the chorioallantois of chick embryos; the following cell combinations were studied: (1) chick skin cells (epidermal and dermal; (CS), (2) mouse skin cells (epidermal and dermal; MS), (3) MS commingled with CS, (4) mouse epidermal cells (Me) commingled with CS, (5) mouse dermal cells (Md) commingled with CS. Reaggregated MS from 13‐ to 15‐day embryos reconstructed typical mouse skin structures: hair and stratified, keratinized epidermis. Similarly, reaggregated CS reconstructed typical feathers and thin nonkeratinized skin. In bispecific CS + MS aggregates, MS from older embryos (14–15 days) completely suppressed feather development, but formed hair and sheets of bispecific chimeric keratinized epidermis. In contrast, MS from 13‐day embryos co‐aggregated with CS did not suppress feather morphogenesis; in such bispecific aggregates both hair and feathers developed, as well as chimeric epidermis. Most striking was the frequent formation in this combination of “chimeric feathers” in which mouse cells were included in feather structures. Me contributed to the epidermal elements of the feather; Md formed groups at the site of the feather dermal papillae. This changeover in mouse cells from participation in feather morphogenesis in aggregates to its suppression is closely correlated with their developmental age. The contributions of these results to the understanding of histotypic specificity and morphogenetic cell interactions are discussed.
Survival of pronuclear mouse eggs kept at different temperatures
Authors: Lin T. P.
Published: June 2005

Pronuclear mouse eggs were maintained in globulin‐citrate‐Locke's solution for 120 to 180 minutes at one of the following temperatures: 22–23°C (room), 35–36°C (incubator) or 2–3°C (refrigerator). Their viability was then compared with that of untouched eggs and with eggs immediately transferred from donor to host. After maintenance at room temperature the vitelline membrane shrank irregularly within the zona pellucida; on the other hand, in the pronuclear eggs maintained at refrigeration temperature this did not occur. In contrast, the cytoplasm of the incubated eggs was highly condensed and the vitellus shrunken, although the vitelline surface remained smooth. Survival rate of eggs, as tested by transplantation, was lower after incubation than after refrigeration. Body weight of fetuses developed from eggs maintained at room temperature and refrigeration temperature was significantly less than that of fetuses developed from untouched control eggs, from eggs immediately transferred to a host animal, or from eggs maintained at incubation temperature.
The growth of newborn rat tibiae in a continuousflow organ culture system
Authors: Schwartz P. L. , Wettenhall R. E. H. , Bornstein J.
Published: June 2005

A technique for continuous‐flow organ culture of newborn rat tibiae in a chemically defined medium is described. The growth characteristics of such bones during three days of culture, in terms of length, weight, hydroxyproline content, galactosamine content, and calcium content, are compared with corresponding growth in vivo and are seen to be reduced, especially beyond the first day of culture. Net synthesis of hydroxyproline and galactosamine during culture is demonstrated.

It is shown that cultured bones are capable of incorporating labelled proline into hydroxyproline and labelled sulphate into bound form linearly for 72 hours, indicating continuing matrix synthesis in vitro.

The implications of these findings are discussed.
Evolution of a nervous system specific lactate dehydrogenase isozyme in fish
Authors: Horowitz Jordan J. , Whitt Gregory S.
Published: June 2005

L‐lactate dehydrogenase (LDH) exists as tetrameric isozymes in all vertebrates. The polypeptide subunits are encoded in at least two genetic loci, A and B. A third LDH locus, the E locus, is present only in fish. The distinctive E4 isozyme encoded by this locus is synthesized in the cells of the teleost nervous tissue, particularly in the photoreceptor cells.

Electrophoretic and immunochemical procedures were employed to determine which orders of fish have representatives which contain this nervous system specific LDH isozyme. In addition to the 50 species of teleostean and non‐teleostean fish examined, a compilation was made of other species reported to contain this enzyme.

The LDH E gene function was not detected in Agnathans, Chondrichthyes, Dipnoans, Chondrosteans, and Holosteans. The LDH E gene appears to be restricted to the teleosts. However, some orders of teleosts, e.g., the Cypriniformes, contain many families which lack the E4 isozyme. The LDH E gene appears to have arisen from a duplication of the LDH B gene near the time of the adaptive radiation of the teleosts.

The immunochemical analyses of the LDH isozymes from these fish indicate that the LDH A and B loci of non‐teleostean fish have not diverged to the extent as these same loci in teleosts.
Reticuloendothelial system activity and antibody formation in hibernating hedgehogs (Erinaceus europaeus)
Authors: Franceschi Claudio , Forconi Giulio , Perocco Paolo , Di Marco Antonino Tano , Prodi Giorgio
Published: June 2005

The reticuloendothelial system (RES) activity by the method of colloidal carbon clearance and the antibody production against heterologous erythrocytes by the method of hemagglutination were studied in hibernating hedgehogs.

The organs involved in RES activity and antibody production were histologically studied.

The data obtained show that the RES activity in the liver is unaffected in hibernating animals while uptake and localization of carbon particles by the spleen is impaired. The suggested hypothesis is that of a defect in the phagocytic activity of the spleen's macrophages, even if the effects of the disturbance in the handling of hibernating animals is to be considered.

The antibody production is inhibited or, at least, reaches no significant values in hibernating hedgehogs.

All these facts may be correlated with a general and marked involution of all the lymphoid organs. In fact we can observe a reduced white pulp and involuted follicles in the spleen, a smaller size of the thymus and its substitution by brown fat tissue, and smaller lymphnodes containing brownish material. The results are discussed in relation to the scanty and contradictory data available in the literature.
Differences in the morphogenetic properties of mouse and chick embryonic liver cells
Authors: Burdick Morton L
Published: June 2005

Aggregates containing trypsin‐disaggregated mouse and chick embryonic liver cells were prepared, and in confirmation of Moscona's reports, no substantial sorting out was seen. While this behavior could mean that the morphogenetic properties of these cells are the same, alternative explanations have not been ruled out. Thus, additional comparisons of these cells were needed to decide whether these properties are the same, and two such tests were performed.

It is known that when two pieces of chick embryonic liver are fused together, neither piece envelops the other. If mouse and chick embryonic liver cells had identical properties, no envelopment would be expected in mouse‐chick liver fusions. Such fusions were prepared, and contrary to this expectation, chick liver enveloped mouse liver almost invariably.

It is known that chick embryonic liver cells sort out from chick embryonic heart ventricle cells in mixed aggregates. If mouse liver cells had properties identical to those of chick liver cells, it would be expected that they too would sort out from chick ventricle cells. Mouse liver‐chick ventricle cell aggregates were prepared, and contrary to this expectation, no substantial sorting out was found.

These two tests demonstrate that the morphogenetic properties of mouse and chick embryonic liver cells are not the same. Clearly, a new explanation must be found for their lack of sorting out, and several possible explanations are discussed.
An electrophoretic and biochemical analysis of acid phosphatase in the tail of Xenopus laevis during development and metamorphosis
Authors: Robinson Helen
Published: June 2005

The properties of acid phosphatase from tail tissues of Xenopus laevis tadpoles have been investigated by means of acrylamide gel electrophoresis and biochemical assay with alpha‐naphthyl acid phosphate as substrate. Studies were made on intact tails during development and spontaneous metamorphosis, and on isolated tail tips undergoing thyroxine‐induced regression in culture.

Quantitative and qualitative changes in acid phosphatase are found to occur during the process of tail resorption. The same types of changes are found during both spontaneous metamorphosis and thyroxine‐induced regression in culture, although the magnitude of these changes is greater during spontaneous metamorphosis. Tail resorption is characterized by increases in total activity (per tail) and specific activity (per unit of protein) of acid phosphatase, as well as changes in the pH optimum and heat sensitivity of the enzyme. Electrophoresis of enzyme preparations from whole tails and different parts of the tail resolves two distinct forms of the enzyme which are both present throughout growth and regression. Densitometric tracings of these gels reveal that the ratio of one form to the other remains constant during growth and the early stages of tail regression. However during late stages of tail regression this ratio becomes significantly altered, due primarily to an increase in one form. Biochemical analysis of enzyme preparations subjected to hypotonic conditions and to Triton X‐100 indicates that there is an increase in the proportion of soluble versus bound enzyme in tail tissues undergoing advanced atrophy. Possible implications of these results are discussed.
Assay of prolactin in vertebrate pituitaries by its dispersion of xanthophore pigment in the teleost Gillichthys mirabilis
Authors: Sage Martin , Bern Howard A.
Published: June 2005

A simple, rapid assay for prolactin is described using the pigment‐dispersing response of the xanthophores in the teleost Gillichthys mirabilis. The assay is highly specific for prolactin in lower vertebrates, but mammalian growth hormone (STH) also produces a response in the assay. The assay is sensitive, detecting 10−11 gm (dry weight) of a teleostean pituitary rostral lobe. Taxonomic specificity is high: 5 μg ovine prolactin is required for a similar effect. Activity in the agnathan pituitary was negligible. In elasmobranchs, teleosts and reptiles, activity was localized in the rostral pituitary region. Lung‐fish pituitary activity was low, resembling that in tetrapods. Comparison of pituitary xanthophore activity from the several vertebrate classes indicates an inverse relationship with pigeon cropsac activity, previously published, suggesting that the evolution of a single active site on the prolactin molecule could account for both activities.
A histological study of the early stages of cutaneous wound healing in lizards in in vivo and in vitro
Authors: Maderson P. F. A. , Roth S. I.
Published: June 2005

The responses of the skin to wounding from six hours to ten days have been studied histologically in a variety of lizard species. Whatever the size of the initial wound, all aspects of cutaneous structure, i.e., general scale architecture, epidermal cell activity, and epidermal specializations, are disrupted by a sequence of cellular events quite distinct from those described in other vertebrates. The epidermis on either side of the incision dies along a variable length, and epithelial migration occurs along a prepared hypercellular path through the dermis where the normal collagen fibers are destroyed. A segment of apparently physically undamaged tissue is discarded from the body surface and the subjacent “wound epidermis” undergoes rapid cell proliferation and maturation leading to the formation of a hyperplastic cornified tissue whose cells resemble the normal α‐layer, but which shows no indication of the typical epidermal generation structure.
Morphological changes in the “prolactin” cell of the freshwater teleost, Xiphophorus hellerii, in salt water
Authors: Holtzman Seymour , Schreibman Martin P.
Published: June 2005

The swordtail, Xiphophorus hellerii, requires prolactin for survival in its natural freshwater habitat. Progressive cytological and ultrastructural changes of prolactin cells were observed in sibling females after a transfer from fresh water to one‐third sea water for periods ranging from 18 hours to 30 days. At the light microscope level, cells became progressively smaller, displayed a decrease in acidophilia, and lost their nucleolar prominence. Electron microscopy confirmed these observations. There was a reduction of perinuclear rough endoplasmic reticulum and a progressive decrease in the size distribution of secretory granules from an average of 2800 Å diameter in freshwater fish to 1700 Å for animals in dilute sea water for 30 days. Furthermore, a class of granules over 3000 Å, representing approximately 45% of the granules in prolactin cells of freshwater animals, were not present after 18 hours in dilute sea water. These observations presumably reflect a diminished requirement for prolactin in a saline environment. Possible alternative explanations for the mechanisms of these changes are discussed.
Effects of temperature on shortening of isolated Rana pipiens tadpole tail tips
Authors: Fry Anne E.
Published: June 2005

To determine how temperature influences the rate of amphibian metamorphosis when acting directly on peripheral tissues, Rana pipiens tail tips from larval stages II–IV were cultured in the presence of 1 × 10−6 M or 1 × 10−7 M DL‐thyroxine at four different temperatures: 5°C, 10°C, 20°C, and 26°C. Five experiments were performed with variations in temperature, length of exposure to, and concentration of, hormone.

Results indicate a positive correlation between temperature and rate of tail shortening in vitro, thus demonstrating that temperature can influence metamorphosis by acting on the periphery directly in addition to its effect on the hypothalamus‐pituitary‐thyroid axis. Low temperatures retard or inhibit shortening of isolated tails both by decreasing thyroxine uptake and by influencing its action after it is within the tail. Length of exposure to hormone and concentration also affect the rate of resorption.
Formation and differentiation of the upper pinacoderm in reaggregation masses of the sponge Microciona prolifera (Ellis and Solander)
Authors: Bagby Roland M.
Published: June 2005

The ultrastructures of gray cells and archeocytes were studied in adult Microciona prolifera to aid in their identification in reaggregation masses. Gray cells were easily identified by their uniform, densely‐stained granules and abundant glycogen particles. A small, dense nucleolus was occasionally observed. Archeocytes lacked the characteristic granules of the gray cell, and a large nucleolus with a less dense core was invariably found.

To follow the stepwise formation and differentiation of the upper pinacoderm, pieces of sponge were squeezed through cloth into polyethylene dishes, and the resultant masses were fixed with 2% OsO4 in 90% sea water at 6, 12, 24, 48, and 96 hours after dissociation. Fixation, dehydration and embedding in the same dish preserved the orientation of the masses.

Reaggregation masses of less than 150 μ diameter failed to differentiate a pinacoderm while in masses greater than 250 μ virtually the entire upper surface was composed of exopinacocytes by 96 hours. The gray cells and archeocytes were little changed from their structure in the intact sponge except for a more rounded shape and a greater number of phagosomes in the archeocytes. Cells forming the surface epithelium contained large nucleoli, phagosomes and other characteristics similar to those of archeocytes, while cell types intermediate between gray cells and exopinacocytes, were not observed. It was concluded that gray cells do not form exopinacocytes, and archeocytes form the nucleolated exopinacocytes.
Middle‐ear function in a monotreme: The echidna (Tachyglossus aculeatus)
Authors: Aitkin Lindsay M. , Johnstone Brian M.
Published: June 2005

The mechanics of the middle ear bones of echidna (Tachyglossus aculeatus) were studied using the Mössbauer technique. A small radioactive source was placed on the stapes and the alterations in the frequency of the emitted γ‐ray, which occurred when the stapes vibrated during sound stimulation, were detected by a proportional counting system and absorber. In this way the velocity of stapes motion could be measured in response to different acoustic frequencies and intensities.

The ossicular system of echidna consists of a large malleus with an anteromedially directed process, the processus gracilus; an incus which is ankylosed to the malleus, and a columelliform stapes. The tympanic bone supports the eardrum and appears firmly locked to the processus gracilus. The malleus and incus are tightly attached, at their lateralmost corner, to the periotic bone. This latter attachment causes the middle ear chain to be very stiff.

The velocity of stapes motion at 100 dB SPL is very low (0.0014 mm/sec) at 100 Hz and rises to a peak at 6 kHz (0.1 mm/sec). Velocity decreases at approximately 12 dB/octave as frequency is increased beyond 6 kHz. Amplitude of stapes motion is relatively constant at about 0.002–0.004 μ for 100 dB SPL between 100 Hz and 6 kHz and drops off at 18 dB/octave at higher frequencies.

Comparison of these results with those for some lizards and placental mammals reveals that the echinda middle ear bones are considerably less efficient in transmitting airborne vibrations than those of the other animals.
Strobilation in the Chesapeake Bay sea nettle Chrysaora quinquecirrha. I. The effects of environmental temperature changes on strobilation and growth
Authors: Loeb Marcia J.
Published: June 2005

Observation of Chrysaora polyps taken from the Chesapeake Bay and maintained in the laboratory reveals at least four morphological types of animals, chiefly distinguished by the number of tentacles they bear and the manner of strobilation. All of the types strobilate when warmed after sufficient chilling; several waves of strobilations may result from the initial stimulus. One of the types of Chrysaora polyps was selected for characterization with respect to environmental control of its strobilation behavior. These animals must be chilled for a minimum of seven weeks at 20°C before they are able to respond to warming to 26°C by strobilating; it is proposed that a number of factors accumulate during chilling which enable polyps to strobilate when warmed. The time course of strobilation, including release of ephyrae, appears to be determined by the temperature at which strobilation is initiated.

The growth of Chrysaora polyps seems to be regulated by both the exact temperature of the environment and relative changes in environmental temperature.
A functional taxonomy of epidermal appendages in mice based on the distribution of nerve endings
Authors: Straile William E. , Mann Stanley J. , Cole Carl E.
Published: June 2005

Existing data on integumental nerve endings provide a basis for classification of the visible epidermal appendages (hairs and dermatoglyphic pads) in mice. Hairs that have long tips (tylotrichs and bristles) are surrounded by large encapsulated cylinders of coarse nerve fibers. Half of these hairs (tylotrichs) are associated with disk‐shaped dermatoglyphic pads, which contain innervated Merkel cells. Hairs that have short tips are surrounded by small cylinders of fine nerve fibers, but contiguous dermatoglyphic pads and dermal capsules are missing. Constrictions in the shafts of short‐tipped hairs vary unpredictably and are not readily correlated with nerve endings.

Analysis of the distribution, structure and physiology of nerve endings and dermatoglyphic pads makes possible (1) the recognition of meaningful features of hair structure (e.g., contour of the tip) that are involved in the transmission of mechanical energy to tactile receptors, and (2) the disregard of equivocal features of hair structure (e.g., 1 constriction in the shaft), which vary between the sexes, among body regions and among inbred strains.