bluuebunny/crossref_metadata_2025 huggingface dataset:
Sequential analysis of marker data for a rare oligogenic disease
Authors: Mitchell Laura E.
Published: June 2005

A sequential scheme for identifying genetic markers, in linkage disequilibrium with disease susceptibility loci, was utilized to evaluate potential associations between a rare oligogenic disease and genetic variation at 360 anonymous DNA markers. ©1995 Wiley‐Liss, Inc.
Integration of linkage analyses and disease association studies
Authors: Nemesure Barbara Berger , He Qimei , Mendell Nancy
Published: June 2005

The REGD procedure of the S.A.G.E. [1994] system was used to determine the mode of inheritance of the rare disease given in Problem 1. The likelihood ratio test statistic indicated that we should reject the hypotheses of dominant and recessive inheritance at the 0.01 level, so codominant inheritance was assumed. The estimated penetrance values computed from the β estimates given by the S.A.G.E. output were 1.0, 0.7, and 0.0 for the AA, AB, and BB genotypes respectively. A sample of three markers from each chromosome was used to determine which chromosome(s) gave evidence of having loci linked to the disease locus. The lod minus 0.83 support interval, which has been shown to provide the best approximation to 95% coverage among interval estimates [Nemesure et al., in press], was obtained for each of these markers. The criterion for rejecting the hypothesis of close linkage using the support interval methodology required that the left side of the lod minus 0.83 support interval about the maximum likelihood estimate, \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm \hat \theta } $\end{document}, includes only values greater than θ = 0.10. This criterion suggested that chromosomes 2, 3, and 6 did not contain the disease genes. Classical lod‐score linkage analysis using the usual criteria of 3.0 for linkage and ‐2.0 for exclusion did not result in any regions being identified. On dropping the required lod score to 1.0, chromosomes 1, 3, and 6 gave results in favor of linkage with lod scores of 1.94 (θ = 0.19), 1.20 (θ = 0.24), and 1.30 (θ = 0.23), respectively. Association studies comparing unrelated cases to unrelated controls were done for all markers on all chromosomes. Two associations were observed which were significant at the 0.05 level after adjusting for the large number of multiple comparisons being made. The strongest association observed was between allele 7 of marker 23 on chromosome 5 and the disease (χ = 52.20, or = 4.7) and the second strongest was between allele 8 of marker 31 on chromosome 1 (χ = 20.10, OR = 3.4). ©1995 Wiley‐Liss, Inc.
TDT with covariates and genomic screens with mod scores: Their behavior on simulated data
Authors: Rice John P. , Neuman Rosalind J. , Hoshaw Stacy L. , Daw E. Warwick , Gu Chi
Published: June 2005

We describe an extension to the TDT (transmission/disequilibrium test) which allows for more than two marker alleles and for covariates measured on the parent or offspring. We also describe a systematic genomic search where the mod score (maximized lod score) is computed for each marker under constraints on the population prevalence or penetrances of a single locus. © 1995 Wiley‐Liss, Inc.
Genetic analysis of a common oligogenic trait with quantitative correlates: Summary of GAW9 results
Authors: Blangero J.
Published: June 2005

The statistical genetic analyses of a simulated data set for Genetic Analysis Workshop 9 Problem 2 are summarized. A diverse set of methods are evaluated with regard to the success with which they were able to determine the mode of inheritance and locate the genes underlying an oligogenically determined disease and four related quantitative traits. © 1995 Wiley‐Liss, Inc.
A brute force dichotomization approach to quantitative trait linkage analysis
Authors: Bailey Julia N. , Almasy Laura
Published: June 2005

The effect of dichotomizing a continuous phenotype in linkage analysis of a simulated oligogenic trait is explored. We conclude that dichotomization does not in itself preclude the detection of loci which account for as little as 16% of the genetic variance of the disease. The effects of inclusion of known covariates and quantitative trait linkage analysis are also discussed. © 1995 Wiley‐Liss, Inc.
Linkage analysis of a common oligogenic disease using selected sib pairs
Authors: Cardon Lon R. , Fulker David W. , Cherny Stacey S.
Published: June 2005

Sib pairs drawn from the simulated common oligogenic disease families were selected for extreme quantitative trait scores and analyzed using interval mapping and multipoint methods. Linkage analyses of 112 selected sib pairs, in which one or more members had trait values exceeding the disease threshold, were compared with analyses of the total unselected sib‐pair sample (771 pairs). Selected sample regression models yielded comparable significance levels to those obtained from the unselected sample at most loci on the six simulated chromosomes, demonstrating the efficiency of selected sib‐pair analysis for quantitative characters. Two of the three disease QTLs were detected in both selected and unselected samples. Interval mapping and multipoint analyses yielded location estimates close to the simulated positions of the QTLs. The combined strategy of using interval mapping and multipoint methods with selected sib pairs appears to provide improved accuracy and sensitivity over more traditional sib‐pair methods for detecting quantitative trait loci. © 1995 Wiley‐Liss, Inc.
Genetic epidemiologic analysis of quantitative phenotypes using gibbs sampling
Authors: Gauderman W. James , Witte John S. , Faucett Cheryl L. , Morrison John , Thomas Duncan C.
Published: June 2005

We analyzed two quantitative traits (Q1 and Q2) provided in the ‘Common Disease’ data set with the aim of detecting both genetic and environmental determinants. We used linear regression for screening measured variables, maximum likelihood segregation and linkage analyses for detecting and localizing unmeasured genes, and Gibbs sampling for joint segregation and linkage analyses with estimation of gene‐environment interaction and polygenic effects. For both Q1 and Q2, we successfully detected the unmeasured codominant major gene (MG) that was tightly linked to candidate gene C2. We also detected all of the measured variables used in generating Q1 (age, Q3, candidate gene C5) and Q2 (EF). Although our final models differed slightly from the true data generation models, our multifaceted analytic approach was successful in characterizing the determinants of Q1 and Q2. © 1995 Wiley‐Liss, Inc.
Use of exact and adjusted liability scores to detect genes affecting common traits
Authors: Goldin Lynn R. , Chase Gary A. , King Terri M. , Badner Judith A. , Gershon Elliot S.
Published: June 2005

We used the Haseman‐Elston sib‐pair test to screen for linkage of markers to genes for disease susceptibility in the simulated data as given in Problem 2 of GAW9. We applied the analysis to the underlying quantitative liability trait (Q1), other covariates of Q1 (Q2‐Q4), and the dichotomous affection status trait. In addition, we analyzed the residual Q1 after adjusting for the covariates. Using the sib‐pair linkage test, we identified a large region of chromosome 5 affecting the residual value of Q1, a region of chromosome 2 affecting Q3, and a region of chromosome 1 possibly affecting Q2. The analysis of the dichotomous traits did not reveal any regions to be significant. This is likely to be due to lack of information since the families were not selected through affected probands. © 1995 Wiley‐Liss, Inc.
A graphical approach for presenting linkage results from a genomic screen
Authors: Pugh Elizabeth W. , Mandal Diptasri M. , Wilson Alexander F.
Published: June 2005

Initially, a sib‐pair linkage analysis was performed between the marker loci and six untransformed variables. Results from several variations of this initial analysis were compared using a graphical approach (P‐plots) to simplify presentation. When results were compared to the generating model, most of the aspects of the generating model were recovered, although we did not find evidence of the polygenic component shared by Q2 and Q3, or evidence of linkage between MG4 and Q4 at the 0.01 level. © 1995 Wiley‐Liss, Inc.
Analysis of familial breast cancer in genetic analysis workshop 9: Summary of findings
Authors: Goldgar David E.
Published: June 2005

As part of the 9th Genetic Analysis Workshop held in Val Morin, Quebec, October 16‐18, 1994, four workshop participants analyzed a large breast cancer data set. This data set consisted of phenotype and genetic marker data on 3884 individuals in 214 families with at least four cases of breast cancer contributed by members of an international breast cancer consortium. Two of the four papers [Barrett and Rigby; Commenges; this issue] utilized variants of affected pair methods to assess linkage of breast/ovarian cancer to the 17q markers in the data set. The third paper by Bansal et al. used a Monte‐Carlo approach to examine the question of intrafamilial clustering of breast and ovarian cancer. The last paper in the series [Leal and Ott] described a method of computing support intervals for risk estimates when there are uncertainties associated with the parameter estimates used to compute these risks. © 1995 Wiley‐Liss, Inc.
Development of the WPC approach and application to linkage analysis of breast cancer
Authors: Commenges Daniel
Published: June 2005

We develop the weighted pairwise correlation approach in several directions: we use a method based on martingale residuals rather than rank residuals; we give a measure of the strength of the linkage and we propose a method for multipoint analysis by combining the weights used in the statistics for different markers. These tools are applied to 214 breast cancer families. The values of the test statistics for the different markers are very similar to those obtained with the lod‐score approach; the multipoint analysis increases the value of the test statistic and is also in agreement with previous results. © 1995 Wiley‐Liss, Inc.
A Chromosome‐based method to infer IBD scores for missing and ambiguous markers
Authors: Gu Chi , Suarez Brian K. , Reich Theodore , Todorov Alexandre A.
Published: June 2005

We propose a probability model to impute missing identical‐by‐descent (IBD) vectors for linkage analysis, when adjacent marker loci are typed and interference is estimable. A chromosome‐based IBD distribution, conditioned on available marker data, is computed using a fast algorithm to estimate the joint probability of genes IBD at several equally spaced linked loci. Weighted IBD vectors are then used in various test statistics for linkage analysis. As an example, we analyzed the 18 affected sib pairs in the GAW9 Problem 1 data set using Risch's lod‐score test. © 1995 Wiley‐Liss, Inc.
The development of isolated and partially separated blastomeres of Amphioxus
Authors: Conklin Edwin G.
Published: June 2005

Blastomeres of the egg of Amphioxus, separated along the plane of the first cleavage, develop into typical embryos and larvae because all materials of the egg are typically localized in each half. Blastomeres separated along the plane of the second cleavage never develop into typical larvae because the mesodermal crescent is largely lacking in the anterior cells and the chorda‐neural crescent lacking in the posterior ones. Isolated micromeres of the 8‐cell stage form blastulae with ectoderm but no endoderm, they never invaginate; macromeres form gastrulae wiht invaginated endoderm but never develop farther.

Partially separated blastomeres develop into partially separated embryos and larvae. Anterior blastomeres of the 4‐cell stage separate more frequently than posterior ones and give rise to embryos and larvae double anteriorly but single posteriorly. Partially separated blastomeres often rotate with respect to each other, but each blastomere invariably preserves its original poles, axes, and germinal localizations. Such rotated blastomeres develop into double embryos and larvae with axes and poles as in the dislocated blastomeres; frequently antero‐posterior and dorso‐ventral axes are completely reversed in the twins.

All axes and poles of the future larva are irreversibly determined at or before the first cleavage; complete regulation occurs only in the plane of bilateral symmetry; except for this bilateral regulation, development in Amphioxus, as also in Ascidians, is a mosaic work.
Fertilizing life of ferret sperm in the female tract
Authors: Chang M. C.
Published: June 2005

For the determination of the fertilizing life of ferret sperm in the female tract, gonadotrophin was intraperitoneally injected to induce ovulation at various times after the deposition of epididymal sperm into the uterine horns. The animals were examined 48 or 60 hours after ovulation injection to assess the proportion of fertilized eggs, although a few of them were allowed to deliver young.

Intraperitoneal injection of 50 hypophysectomized R.U. of sheep pituitary extracts or 90 I.U. of Human Chorionic Gonadotrophin invariably induced ovulation in ferrets that were in heat. Ovulation occurred about 24 to 36 hours after the administration of H.C.G. and an average of 14.5 eggs with a range of 8 to 24 eggs per animal was obtained.

The average number of sperm in the cauda epididymides and the vasa deferentia of nine males was 219 millions with a range of 24 millions at the end of breeding season to 621 millions at the peak of breeding season.

The percentage of total eggs that were fertilized was 73, 40, 24, 15, 3, and 0 when the ovulation injection was given at 0, 36, 72, 84, 96, and 108 hours after sperm deposition respectively. Since ovulation occurred 30 hours after ovulation injection the fertilizing life of ferret sperm in the female tract is therefore no more than 126 hours. The percentage of eggs fertilized was lower following the deposition of epididymal sperm than following mating (73% vs. 98%). There is evidence that the fertility of sperm in the female tract was higher if a large number of sperm was deposited, and that the penetration of sperm into the egg facilitated the denudation of the egg.

The majority of the penetrated eggs (54 to 84%) were at the pronuclear stage 48 hours after insemination and ovulation injection (i.e., about 18 hours after ovulation), at 60 hours (30 hours after ovulation) the majority of them were either at pronuclear stage (26–100%) or at the 2‐cell stage (46–57%), and at 70 hours (40 hours after ovulation) most of them were at the 4–6 cell stage. The morphology of fertilization in the ferret and the time sequence after sperm penetration were described.
Spontaneous melanoma in regenerating tails of axolotls
Authors: Sheremetieva E. A.
Published: June 2005

Relationships between neoplasia and regeneration were studied in the regenerative processes following 21 amputations through or near 8 spontaneous melanotic formations in the tails of axolotls. It was found that spontaneous melanoma can grow in the presence of regeneration, but that melanotic ingrowth into a regenerate tends to be limited to temporary “symbiotic” participation of the melanotic tissue in the development of the regenerate. It was also found that regeneration is almost always essentially normal in the presence of a spontaneous melanoma, even when the regenerate grows from the tumor itself or from a previous regenerate that is black with melanotic cells.

Melanotic cells are presumably derived from normal pigment cells, and some investigators have suggested that neoplastic cells under the influence of regenerative processes may occasionally be transformed back into normal cells. The present study has provided no evidence that such a transformation ever occurs. Instead, the regenerative processes seem only to limit the neoplastic activity of melanotic cells that participate in regenerative growth. In fact, when regeneration is abnormal, melanotic cells may behave much as they do in the absence of regeneration.
The role of interstitial cells in the maintenance of hydra II. Budding
Authors: Diehl Fred A. , Burnett Allison L.
Published: June 2005

Animals whose interstitial cells have been selectively destroyed by nitrogen mustard continue to form new buds for nine days after mustard treatment. Buds present on parent animals at the time of mustard teatment continued to develop at the same rate as control animals; however, in most cases they failed to detach as quickly as control forms.

Extensive histological examination revealed a lack of mitoses in gastrodermal digestive cells after nitrogen mustard treatment. Divisions continued in epidermal epithelio‐muscular cells for as long as 20 days. It is suggested that cell divisions in the epidermis are necessary for the initiation of the budding process and that under the present conditions the gastrodermal cells are pulled along passively into the bud outgrowth.
On the nature of the restricted differentiation‐promoting ability of transplanted Rana pipiens nuclei from differentiating endoderm cells
Authors: Subtelny Stephen
Published: June 2005

Many diploid Rana pipiens endoderm nuclei from late gastrulae and neurulae demonstrate restrictions in their ability to promote normal development when transplanted into enucleated host eggs. To obtain information on the nature of these restrictions the nuclear descendants of 26 different endoderm nuclei from advanced embryos were injected into groups of enucleated and nucleate (non‐enucleated) haploid host eggs. In none of the 26 serial transfer experiments in which the enucleated test eggs revealed abnormal development did the nucleate test eggs show normal development. Consequently, the results demonstrated that the restrictions in differentiation‐promoting properties of transplanted diploid endoderm nuclei were dominant in the sense that they were not corrected to totipotency by combining them with “undifferentiated” haploid egg pronuclei.

While ten control serial transfer experiments with blastula nuclei produced normal larvae associated with euploid chromosome complements, about half of the serial transfer experiments with nuclei from differentiating endoderm cells produced abnormal embryos associated with gross chromosome abnormalities. The other half of the serial transfer experiments analyzed for chromosome number were associated with apparently normal chromosome complements. Some produced normal diploid and triploid individuals from enucleated and nucleate host eggs respectively, demonstrating the transplanted nuclei to be totipotent. Others produced abnormal diploid and triploid embryos, the majority of which exhibited deficiencies consistent with the endodermal origin of the donor nucleus. The latter triploids did not display any further development than nucleate eggs in the experiments associated with definite gross chromosome abnormalities. In addition, variations were noted in the development of the diploid and triploid embryos and in the severity of their deficiencies which could not be ascribed to poor egg quality. They indicated differences among the donor nuclei, which may include chromosome rearrangements, but not chromosome number. Some experimental evidence has been presented which indicates that the chromosome aberrations may reflect restrictions in nuclei of differentiating endoderm cells which result in a proclivity of the donor chromosomes to replicate abnormally in host egg cytoplasm.
Differentiation of multiple molecular forms of four dehydrogenases in the teleost, Oryzias latipes, studied by disc electrophoresis
Authors: Nakano Eizo , Whiteley Arthur H.
Published: June 2005

The isozymic forms of four dehydrogenases, separated by disc electrophoresis in acrylamide gels, have been studied during development and in adult organs in the cyprinodontiform fish, Oryzias latipes, the medaka. Xanthine dehydrogenase appears as a single molecular form at hatching, and in the adult fish is found only in the liver and gut. Glucose‐6‐phosphate dehydrogenase is a single enzyme in early development, just before hatching two new forms appear, and after hatching all three decrease in whole larval extracts. In adults, the enzymes were found only in brain, liver, and ovary. Malate dehydrogenase increases from a single molecular form in early stages to five or six after hatching. Each adult tissue has its characteristic assemblage of isozymes. The only lactate dehydrogenase detectable before hatching is isozyme 5, and four others appear abruptly at hatching. All adult organs have one to three LDH isozymes, but isozymes 1 and 2 were found only in the retina of the eye. The abrupt change from the single isozyme 5 to the full complement occurs also in eyes of the larvae taken pre‐ and post‐hatching. Homogenates of pre‐hatching embryos do not inhibit the electrophoretic separation or reactivity of isozymes 1, 2, 3, and 4 of post‐hatching larvae. Presumably hatching triggers the appearance of the more rapidly migrating isozymes, especially strongly in the retina. On the basis of the structure of LDH isozymes in other organisms, it can be concluded that polypeptide A is present before hatching, but some restraint on the synthesis or activation of polypeptide B seems to be removed by hatching. The importance of hatching as a time of qualitative change in these four enzymes is correlated with increases in other metabolic activities at this time.
Fine structural changes in the nervous system of the regenerating hydra
Authors: Lentz Thomas L.
Published: June 2005

The fine structure of neurons from regenerating hydra was studied. The ganglion cells of regenerating hydra in contrast to those of normal hydra contain denser and sometimes multiple nucleoli, polyribosomes, and membrane‐bounded accumulations of dense homogeneous material which appears to be elaborated by the Golgi apparatus. During regeneration, membrane‐bounded dense granules disappear from the perikaryon of neurosecretory cells and accumulate in the processes. They are released by fusion of the vesicle membrane with the plasma membrane of the neurite. A large number of intermediate stages of differentiation of neurons from interstitial cells are present after 12 hours of regeneration. These observations support the hypothesis that neurosecretory substance released at nerve terminals plays a significant role in the regulation of growth and differentiation in the regenerating hydra.
Trophic responses to trauma in growing antlers
Authors: Bubenik Anthony B. , Pavlansky R.
Published: June 2005

The effects of trauma on antlers, pedicles and/or frontal bones in roe‐, red‐ and fallow‐deer during the period of antler growth were investigated. The following results were obtained: (1) antler regeneration originates from the osseous part of the pedicle or frontal bone and is not restricted to the hypothetical “Bildungssaum” or so‐called regenerative rim. (2) Unilateral trauma of a growing antler stimulates a trophic response on the control side only when the base of the pedicle, that is, the generative region of antler production, has been heavily injured. In such circumstances supernumerary and dislocated pedicles may be produced. Not infrequently the abnormality caused by unilateral trauma to the germinative bud may reappear in the next antler cycle in the same place but in a more intensified form. In general it may be found that there is a direct correlation between the trophic response to trauma and the stage of antler growth, i.e., the earlier the period of growth the more vigorous the trophic response to the trauma. Moreover, it may be that the antler cycle on the one pedicle may be accelerated or slowed down owing to trauma or other factors so far unknown. There are even cases on record where the antler on one side only may be affected differently by hormonal factors than the opposite side. All these findings have led the authors to the conclusion that each of the frontal bones, as a base for the pedicles and antlers, may have a center of antler stimulation of its own. It is assumed that in these centers (dispositions) a “pattern of antler form” is integrated. This is the only possible explanation for the memory of antler injuries on the one hand and the unilateral disturbances of antler growth on the other. It is suggested that the hormones which influence antler growth exert their effects via neural trophic centers and may thus be directed only to one antler or to a certain zone of it. Conversely, it is possible that the specific hormone may be prevented by the neural trophic centers from acting on the tissues of one antler or a certain zone of it. The site of such trophic centers is supposed to be the hypothalamus.
Studies on the incorporation of isotopically labeled nucleotides and amino acids in planaria
Authors: Best Jay Boyd , Rosenvold Robert , Souders Jacqueline , Wade Carlton
Published: June 2005

Neither intact nor regenerating planaria incorporated any significant amount of tritiated thymidine, tritiated L‐leucine, or C14‐L‐leucine from free solution even over long periods of exposure. Tritiated thymidine was incorporated into regenerating rat liver and fed to planaria, but tritium hydrogen exchange rendered this method useless. A large incorporation of C14‐uracil and C14‐L‐leucine into planaria was obtained by growing baker's yeast in a defined medium containing the labeled compound and then feeding the acetone dried yeast to the planaria. C14 assay of the amino acid components of planaria fed on C14‐L‐leucine labeled yeast showed C14 in only the L‐leucine component and yielded a minimum estimate for protein turnover of 46% in seven weeks. Radioautographs of planaria fed on C14‐uracil labeled yeast exhibited specific incorporation into ribonucleic acid. Previous radioisotopic studies on planaria are evaluated and criticized. The amino acid composition of planarian protein was determined.
A study of strobilation in Aurelia aurita under controlled conditions
Authors: Spangenberg Dorothy Breslin
Published: June 2005

The maintenance of Aurelia aurita polyps in this laboratory has made possible the study of strobilation under well controlled laboratory conditions for the first time. The development of pulsing, statocysts and gastric filaments during normal strobilation occurring in artificial sea water at constant temperature was observed. Comparisons made of intact strobilae and segments cut from strobilae revealed that isolated segments of strobilae differentiated at a rate comparable to segments of intact strobilae. Furthermore, segments and pieces of segments which appeared morphologically to be polyp tissue and which exhibit no differentiation of structure were already “programmed” to become medusa tissue. Since isolated completed segments developed into ephyrae without further contributions of cells or substances from the parent it was postulated that segments of intact strobilae are, likewise, independent in their development once segments are completed.

Studies of atypical strobilation resulting from simple environmental change emphasized that mechanisms that regulate segmentation are different from and probably independent of those that regulate metamorphosis of the segments into ephyrae.

A discussion of the major processes involved in strobilation is presented and a close analogy to the metamorphosis of higher animals is drawn. The value of this primitive form of metamorphosis for studies of mechanisms involved in growth and differentiation is demonstrated.
Reconstitution of the spinal cord following ablation in urodele larvae
Authors: Butler Elmer G. , Ward Margery B.
Published: June 2005

After ablation of 2 mm of spinal cord in the postbrachial region in larvae of Ambystoma maculatum studies were made on the reconstitution of the cord and the return of function posterior to the ablation level.

Healing of the cord at anterior and posterior transection surfaces involves migration of ependymal cells to close the open central canal and movement of cells of the gray matter over the cut surface. Dilation of the central canal occurs at each transection level to form a terminal vesicle. Its wall is made up of ependyma, cells from the gray matter and an outer layer of white matter. Anterior and posterior terminal vesicles gradually increase in length bringing about a slow advance of their tips across the ablation gap, the anterior vesicle moving more rapidly than the posterior.

Nerve fibers growing out from the white matter of each terminal vesicle extend across the ablation gap and eventually join the wall of the opposite vesicle. Thus are formed bridges of intracentral fibers between anterior and posterior vesicles. Broad nerve fiber bridges become the white matter of the reconstituted spinal cord. Continued advance of the terminal vesicles across the ablation region results finally in the union of the two vesicles, restoring the continuity of the spinal cord.

Recovery of the use of hind limbs for walking and of trunk and tail muscles for swimming is correlated with the extent to which nerve fiber bridges have been established, but does not involve a complete fusion of terminal vesicles. All larvae which walked normally and the majority of those which swam normally possessed fiber bridges with an average diameter of at least 0.05 mm.
Production and utilization of reduced nicotinamide adenine dinucleotide phosphate in the mouse testis
Authors: Hitzeman Sister Jean Walter
Published: June 2005

Testicular Leydig cells of BALB/c Jax mice exhibit time‐dependent patterns of nicotinamide‐adenine‐dinucleotide‐phosphate (NADP)‐linked glucose‐6‐phosphate and isocitrate dehydrogenase activity beginning five days before birth. In crude homogenates of fetal testes, glucose‐6‐phosphate dehydrogenase (G‐6‐PDH) activity is twice that found in the adult. Levels drop at birth and remain low. Isocitrate dehydrogenase activity is high during late gestation and at 10 and 60 days postpartum, but decreases in the neonatal and the prepubertal testis. Moderate prenatal NADPH‐diaphorase activity is reduced in the postpartum animal. Conversely, there is a steady increase in reduced nicotinamide‐adenine‐dinucleotide (NADH)‐diaphorase activity after birth, with adult levels being attained by the third week. Inhibition of testicular G‐6‐PDH activity by pregnenolone, dehydroepiandrosterone, and cholesterol is proportional to steroid concentration between 10−6 M and 10−4 M.

The production of NADPH by isocitrate and glucose‐6‐phosphate dehydrogenases assures sufficient reducing potential for the early synthesis of androgens in fetal interstitial cells. The sustained depression in G‐6‐PDH activity found in the postpartum testis may be due in part to regulation by steroid intermediates. Hormonal precursors have no effect on isocitrate dehydrogenase which continues to supply NADPH in the postpubertal testis.
A study of induced metamorphosis in the Axolotl
Authors: Prahlad K. V. , DeLanney Louis E.
Published: June 2005

Metamorphic changes occurred in dark and white Mexican axolotls injected with 3,3′,5‐triiodo‐L‐thyronine (T3) or DL‐thyroxine (T4), when exposed at the following ages (in days) after spawning: 3–8, 45, 62, 117, 521–541, 541‐571, at 20°C. The dosage of the hormone administered as a single injection varied from 10 μg to 100 μg. Optimum conditions in group 1 proved to be 10 μg T3 injected into the perivitelline space of six‐day‐old embryos which were subsequently released from the jelly to fresh water nine days later at 15 days of age. After two days in fresh water tissue changes were observed in this order: gills — ventral, middle, dorsal; tailtip; skin; upper eyelid. T3‐treated animals had a shorter latent period than T4 groups. There was heavy mortality in younger animals. Surviving axolotls completed metamorphosis within 25 to 35 days. Embryonic tissues, therefore, are capable of taking up the hormone and responding after the treatment is terminated, raising doubts as to the obligatory persistence of the hormone. The implications of these observations with regard to the effect of hormone at the molecular level are discussed.
Synthesis and storage of a nerve growth protein in mouse submandibular glands
Authors: Burdman Jose A. , Goldstein Milton N.
Published: June 2005

A series of experiments were designed to determine the origin of a nerve growth promoting protein found in high concentration in the tubular portions of the submandibular glands of adult male mice. This protein is necessary for the growth and development of immature sympathetic nerve cells. The quantities of this protein can be increased in the glands of female mice to levels found in the submandibular glands of adult male mice by injecting testosterone into preadolescent or adult female mice. When testosterone was given to young mice or to adult female mice together with an antiserum prepared against the nerve growth factor (NGF), the NGF content of the testosterone‐treated mice increased in the same manner as in testosterone‐ and normal serum‐treated mice. Although antiserum against the nerve growth protein could be demonstrated in the sera of mice during the course of the entire experiment, the antiserum had no effect on the content of NGF in the submandibular glands. After the intravenous injection of NGF in large quantities, it could not be localized in liver, spleen or submandibular gland cells of the mouse as determined by fluorescent antibody techniques. The results suggested that the nerve growth promoting protein found in high concentration in the submandibular glands of adult male mice and in testosterone‐treated female mice is synthesized and stored in cells of the tubular portion of these glands.
Amino acid incorporation into protein during the molt cycle of the land crab, Gecarcinus lateralis
Authors: Skinner Dorothy M.
Published: June 2005

This is the first of a series of studies on protein synthesis and its control during the molt cycle of the land crab, Gecarcinus lateralis. Incorporation of valine‐1‐C14 and leucine‐1‐C14 into proteins of blood, epithelium, midgut gland, and muscle has been measured at each stage and found to reach a maximum rate in all tissues during the stages D0 through D2 of the premolt period. This period is not necessarily the period of maximum net synthesis of total protein in all tissues. Total muscle protein, in fact, is decreasing at this time: the high incorporation rate may reflect synthesis of degradative enzymes.

In control experiments on possible rate limiting features in amino acid incorporation, the pool sizes of valine and leucine in plasma water were determined. These do not vary systematically with stages in the molt cycle; the relatively small fluctuations in these pools do not correlate with the larger fluctuations in incorporation rate. The sizes of these pools do not appear to be rate limiting. In conjunction with these measurements, the plasma water volume of Gecarcinus was found to be 22 ± 1.72 (S.D.) per cent of the body weight.

It is also shown that the rate of penetration of amino acid from plasma water into intracellular water was not the rate limiting step in the incorporation of C14‐leucine into muscle protein. (Muscle is the tissue with the lowest incorporation rates.) Leucine penetrates muscle readily and appears to be concentrated four‐fold in muscle water relative to plasma water.
Onset of cerebral electrical activity associated with behavioral sleep and attention in the developing chick
Authors: Peters Joseph , Vonderahe Alphonse , Schmid David
Published: June 2005

Bipolar electrical recordings from the cerebral lobes of chick embryos and of freely moving chicks after hatching indicate that spontaneous electrical activity begins about the eleventh to thirteenth day of incubation, but electroencephalographic patterns characteristic of behavioral sleep or attention appear within six hours after hatching. High amplitude, slow waves, are characteristic of behavioral sleep; low amplitude, fast waves are characteristic of behavioral attention. During sleeping postures the electroencephalographic record shows brief cyclic episodes of lower voltage fast waves (paradoxical sleep) and these cycles appear more definitely as the chick grows older. When the act of waking from sleep is associated with the opening of only one eye, the lower voltage, fast waves may appear only in the contralateral lobe, while the ipsilateral lobe shows the high amplitude slow waves. In the less mature chicks, the electrical waves are slower, less regular, and of smaller amplitude, especially during sleep, furthermore the cyclic episodes of activated sleep are less distinct and the span of attention is more brief. Although chick embryos may move following tactile stimulation, the response is probably due to reflex arcs involving lower nervous centers since the cerebral lobes do not show the transition to lower voltage faster waves characteristic of attention. After hatching electroencephalographic patterns associated with sleeping postures show more conspicuous developmental changes than those associated with attention.
Gene and phenocopy: Selection experiments and tests with 6‐aminonicotinamide
Authors: Landauer Walter
Published: June 2005

The problems at issue concerned the epigenetic responses of chicken embryos to 6‐aminonicotinamide (6‐AN). It had been known that injected 6‐AN is responsible for malformations of the appendicular and facial skeleton (micromelia and parrot beak, respectively) and that the resulting syndrome of malformations resembles the phenotypic features of a number of independent mutations. The questions raised by our tests related to the following problems: Does heterozygosity in one of several of the micromelia‐syndrome transmitting recessive genes alter responsiveness to 6‐AN by raising the incidence of induced micromelia and parrot beak and, on the other hand, does a genotype which had been modified by selection toward low expressivity of the micromelia and parrot beak syndrome, again in heterozygous condition, result in reduced responsiveness to 6‐AN? It is concluded from the results of our test that (a) the gene mmA of the California micromelia traits promotes, in single dose, responsiveness to 6‐AN; (b) that multiple modifying genes which tend to suppress the ch/ch genotype of Lamoreux's chondrodystrophy greatly reduce, in single dose, the responsiveness of embryos to 6‐AN. It is concluded, finally, that these results satisfy for the micromelia and parrot beak syndrome, induced by 6‐aminonicotinamide, the definition of phenocopy which was implied by the hypothesis from which the present venture started, viz., that the metabolic pathways of gene and induced effect must be sufficiently related to permit interaction during development.
Experiments concerning the cleavage furrow in invertebrate eggs
Authors: Rappaport R.
Published: June 2005

Dividing eggs of Echinarachnius parma, Hydractinia echinata, Cerebratulus fuscus and Mytilus edulis were subjected to experiments designed to yield additional information concerning the cytoplasm in the cleavage plane. Answers to the following questions were sought: (1) Will the base of the furrow cut itself upon a needle placed in its path at right angles to the cleavage plane? (2) What part of the surface is responsible for the constricted shape of the partly divided egg? (3) Does completion of furrowing depend upon a specific subsurface cytoplasmic arrangement? It was found that in no case could the base of the furrow cut itself upon a needle. The constricted shape of the partly divided Echinarachnius egg depends on the integrity of the surface at the base of the furrow. The eggs of all four species completed division despite drastic stirring and mixture of subsurface cytoplasm which was begun during early stages of furrowing and continued until the blastomeres were separated.
The effects of mercaptoethanol on cellular development in Tetrahymena pyriformis
Authors: Gavin Ray H. , Frankel Joseph
Published: June 2005

The effects of β‐mercaptoethanol on cell division, nuclear division, and oral morphogenesis were investigated in two strains of Tetrahymena pyriformis, WH‐6 (micronucleate) and GL (amicronucleate). Mercaptoethanol inhibited division in both strains. In exponentially growing cell cultures, cell multiplication stopped after a 30 minute lag (strain WH‐6); in synchronized cultures, division was prevented or very greatly delayed if the agent was added during the first 60% of the interval between the end of the last synchronizing shock and the synchronous division.

In both strains, mercaptoethanol brought about an arrest of oral primordium development in cells which had not yet begun to form visible membranelles at the time of addition of the drug. In cells arrested just prior to the onset of membranelle development the oral primordia became disorganized and in many cases were gradually resorbed. In these cells micronuclear division was generally arrested (strain WH‐6) and macronuclear and cell division did not occur at all (strain WH‐6), or were resumed after a long delay (strain GL).

Cells which were in stages of visible membranelle development at the time of addition of mercaptoethanol continued to develop. In strain WH‐6, all of these cells completed oral development and divided, while in strain GL about 40% of these cells were arrested in the course of membranelle development. In these arrested cells, the oral primordia were resorbed, and division did not take place.

In the situations in which oral morphogenesis was completed and cell division took place in mercaptoethanol, micronuclear division (in strain WH‐6) was in all cases normally completed. Macronuclear division in strain WH‐6 was also normal at the minimum concentration (4 × 10−2M) which affected morphogenesis when added at earlier stages. However, at a somewhat higher concentration (5 × 10−2M) in strain WH‐6, and at the lowest concentration employed (1.5 × 10−2M) for strain GL, macronuclear division was either prevented (in both strains) or else rendered highly abnormal (in strain GL).

These data suggest that mercaptoethanol blocks some process required for the initial organization of oral structures and for the division of the macronucleus. The nature of this process is discussed.
Increased sexual behavior in the male rat following lesions in the mammillary region
Authors: Lisk Robert D.
Published: June 2005

Copulatory output of the mature male rat was measured over an eight week period under conditions of each male having free access to a constant stimulus female.

Of 71 males tested 31 of these (44%) had to be discarded as they did not reach our arbitrary minimum criterion of producing copulation plugs on 4 out of 14 nights during the initial (control) observation period. An extreme individual variability in sex drive was noted among the animals used for further testing.

Employing equal sized groups of about ten animals and using a two week interval as the basic unit of time; the mean sexual activity for the group measured as number of copulation plugs found and mean percentage of nights on which copulation occurred indicated an extreme similarity of all groups. Maximum sexual response occurred during the initial 14 day test period and both measures of activity used (copulation plugs and days on which copulation occurred) declined by approximately 50% over the eight week test period.

A similar 50% decline in response occurred following lesions in the middle hypothalamus dorsal to the arcuate nucleus or lesions dorsal to the hypothalamus involving the habenula and surrounding cortex. It was concluded these areas are not involved in regulation of copulatory behavior in the male rat.

Lesions in the mammillary region (mostly medial) resulted in 50% of the animals showing a sustained constant copulatory output during the eight week test, while the remaining 50% (mostly with lateral lesions) showed marked increases which expressed as the mean of the group amounted to 90% copulation plugs and 50% in nights on which copulation occurred.

Thus it was concluded that structures in the mammillary region at the junction of the diencephalon and mesencephalon normally exert a regulatory (inhibitory) influence on the sex drive in the male rat.
Relation of impulse conduction to electrically induced release of neurosecretory material from the urophysis of the teleost fish Tilapia mossambica
Authors: Fridberg G. , Iwasaki S. , Yagi K. , Bern H. A. , Wilson D. M. , Nishioka R. S.
Published: June 2005

The caudal neurosecretory system of the teleost Tilapia mossambica was subjected in vivo and in vitro to intense and prolonged electrical stimulation. Repeated firing of neurosecretory units was observed in the in vivo preparations, and compound action potentials were recorded in vitro. Evidence of depletion of neurosecretory material from the urophysis was obtained on the light and electron microscope levels. Ultrastructurally two pictures were encountered in the responding axon terminals: (1) a decrease in electron density of most of the elementary neurosecretory granules in individual terminals; (2) complete or nearly complete disappearance of granules and vesicles from individual terminals. The latter picture is considered to be a more advanced stage of depletion.
The comparative submicroscopic cytology of the corpus allatum‐corpus cardiacum complex of wild type and fes adult female Drosophila melanogaster
Authors: King Robert C. , Aggarwal Surinder K. , Bodenstein Dietrich
Published: June 2005

The submicroscopic morphology of the corpus allatum‐corpus cardiacum complex of wild type adult female Drosophila melanogaster is described. These endocrine organs are compared with those of females homozygous for the recessive, female sterile gene, fes. The corpus allatum is known to produce a hormone influencing vitellogenesis. The ultrastructure of the gland suggests that this hormone is synthesized by a smooth surfaced, membranous system organized into a reticulum of filaments and tubules from which vesicles are derived by abscission of terminal and lateral blebs. The allatum cells of genetically ovatectomized, fes females are inhibited from releasing the hormone they synthesize. They swell and undergo characteristic, degenerative changes. The corpus cardiacum consists of a central bundle of axons surrounded by cortical cells. Many of the axons are thought to originate as projections from specialized, secretory neurons residing in the pars intercerebralis. Neurosecretory spheres are carried posteriorly in these axons by traveling bulges. The cortical cells contain myriads of neurosecretory spheres suspended in their cytoplasm, and most of these are believed to have been donated by contiguous axons. Cortical cells are also characterized by an extensive, rough surfaced, endoplasmic reticulum consisting of interconnected bloated cisternae which arise from localized, blister‐like proliferations of the outer membranes of the nuclei. The cortical cells of fes females also swell, and their nuclear blisters reach immense sizes. Vitellogenesis within a wild type ovary previously implanted into the abdomen of fes females is accompanied by release of products from the host allatum and cardiacum cells and the return of these cells to their normal morphologies.
Bicaudal, a genetic factor which affects the polarity of the embryo in Drosophila melanogaster
Authors: Bull Alice Louise
Published: June 2005

An inherited disturbance in egg polarity has been observed in Drosophila melanogaster. The bicaudal abnormal embryos develop the terminal segments of a second larval abdomen in mirror‐image symmetry to the terminal segments of the normal abdomen. The two abdomens may be symmetrical with four or five segments at each end of the egg or have more abdominal segments at the normal posterior end than at the reversed end. The reversed posterior ends appear to have normal spiracles, hindgut and Malpighian tubules. The bicaudal embryos and two other specific lethal types associated with them are produced in very low frequency. The production of these lethals is associated with an unmarked second chromosome, which has been carried in three separate inbred lines in combination with a Curly, Lobe, speck balancer chromosome. Flies homozygous for the chromosome and flies heterozygous for this chromosome and a second chromosome containing a deficiency at the vestigial locus can produce the syndrome. Reciprocal crosses, of flies of a genotype which can produce the syndrome with flies which do not, have shown that the maternal genotype is the controlling factor in the production of the abnormalities.