bluuebunny/crossref_metadata_2025 huggingface dataset:
Trophic exchanges between parent and young during development of Glossiphonia complanata (Annelida, Hirudinea)
Authors: De Eguileor Magda , Daniel Sergio , Giordana Barbara , Lanzavecchia Giulio , Valvassori Roberto
Published: June 2005

Glossiphoniids are iteroparous hirudineans that brood their offspring. The young are attached by the posterior sucker to the parent's ventral side until development is complete. The weight loss of the brooding adults is commonly attributed to their reduced possibility of feeding and to the increased metabolic expense for movements needed to ventilate the offspring. The present study showed that there is a passage of nutritive substrates between the parental body wall and the young's sucker. A possible correlation between this passage and the reabsorption of some muscle fibers that occurs in the adult's body wall is also analyzed. © 1994 Wiley‐Liss, Inc.
Estrogen and progesterone receptors in lizard Podarcis s. sicula oviduct: Seasonal distribution and hormonal dependence
Authors: Paolucci M. , Di Fiore M. M.
Published: June 2005

Both estradiol (ER) and progesterone (PR) receptors have been found in the oviduct of the lizard Podarcis s. sicula. Their concentrations change according to the reproductive cycle and under different hormonal treatment. The estradiol receptor binds DES with high affinity (Kd = 4.4 ± 6.9 × 10−1 M) and low capacity (7.0 ± 2.1 × 10−10 M). The progesterone receptor binds both 3H‐progesterone and 3H‐R5020 with high affinity (Kd = 1.2 ± 2.2 × 10−9 M) and low capacity (0.5 ± 2.2 × 10−10 M). PR elution profile on DNA‐cellulose shows two peaks eluting at 0.15 M NaCl and 0.27 M NaCl for the cytosol and 0.14 M NaCl and 0.26 M NaCl for the nuclear extract. When analyzed by isoelectrofocusing, PR shows two peaks at pH 7.8–8.0 and 6.8–7.0. During the reproductive cycle, the peak of occupied ER in the nuclei precedes the increase in occupied PR. This pattern suggests a sequential action of estradiol and progesterone on the oviduct. In fact, while estradiol is involved in oviduct growth in early spring, progesterone stimulates glandular activity in the mature oviduct. Long term estradiol treatment up‐regulates nuclear occupied PR, but down‐regulates it when administered in combination with progesterone. On the other hand, progesterone alone or in combination with estradiol, prevents 17β‐estradiol effects on nuclear occupied ER. © 1994 Wiley‐Liss, Inc.
Tissue‐specific expression of calbindin‐D28K gene during ontogeny of the chicken
Authors: Sechman A. , Shimada K. , Saito N. , Ieda T. , Ono T.
Published: June 2005

The vitamin D3‐dependent calcium binding protein, calbindin‐D28K (CaBP‐D28K), plays an important role in transepithelial calcium translocation. To evaluate its role in chick embryonic calcium metabolism, steady‐state levels of CaBP‐D28K mRNA in various tissues of the chick embryo were determined by Northern blot and slot blot analyses, and CaBP‐D28K concentrations in the examined tissues and plasma were estimated by RIA. High levels of CaBP‐D28K mRNA were found in the embryonic kidney (mesonephros) on embryonic day (E) 10 and E12 and thereafter gradually decreased until hatching. CaBP‐D28K mRNA levels were low in the yolk sac until E16 but increased on E18 and reached a maximum on E20. A steady increase in CaBP‐D28K mRNA levels was observed in the cerebellum during the development from E10 to post‐hatching. CaBP‐D28K mRNA levels in the intestine were very low during the incubation period but significantly increased on days 1 and 7 after hatching. By Northern blot analysis, CaBP‐D28K mRNA was barely detectable in liver, heart, and chorioallantoic membrane of the embryonic chick. Changes in immunoreactive CaBP‐D28K of each tissue paralleled observed changes in mRNA levels. In plasma, measurable levels of CaBP‐D28K were found as early as E8 and were stable until E18, when 6.5‐fold increase was observed compared to E16. The highest level of CaBP‐D28K in plasma was found on E20 and decreased after hatching. These temporal profiles of CaBP‐D28K suggest that it may play an important role in the regulation of chick embryonic calcium homeostasis. © 1994 Wiley‐Liss, Inc.
Monoclonal antibodies to testicular autoantigens of a teleost, the Nile tilapia, Oreochromis niloticus
Authors: Mochida Kazuhiko , Adachi Shinji , Nakamura Ikumi , Yamauchi Kohei
Published: June 2005

In teleosts, several autoantigens, so‐called sperm‐specific antigens, are expressed on the germ cell surface during spermiogenesis and are thought to have sperm‐specific functions. To investigate the functions of the autoantigens in Nile tilapia, Oreochromis niloticus, monoclonal antibodies to these polypeptides were produced. Balb/c mice were immunized with the autoantigens purified from the detergent‐solubilized sperm protein by antisperm autoantibody affinity chromatography. Four hybridomas producing specific antibodies to the autoantigens were obtained. The monoclonal antibody, TAT (Testicular Antigen of Tilapia)‐10 recognized a 27 kDa antigen. This antigen was localized in A and early B type of spermatogonia, spermatids in late spermiogenesis, and spermatozoa. This antigen was located primarily in the mid piece of the spermatozoa. Another antibody, TAT‐20, recognized a 80 kDa polypeptide and another of about 40 kDa. TAT‐21 recognized only a 80 kDa antigen. The antigens recognized by both TAT‐20 and 21 were localized in spermatids in late spermiogenesis and in spermatozoa. TAT‐30 reacted with a 120 kDa antigen which was localized in the epithelium of seminal ducts, Sertoli cells and spermatozoa. The antigens recognized by TAT‐20, 21, and 30 were primarily on the head of spermatozoa. The possible functions of these autoantigens were discussed. © 1994 Wiley‐Liss, Inc.
Ontogeny of feeding in pigeons: A cinefluoroscopic and electromyographic analysis
Authors: van Gennip E. M. S. J. , Berkhoudt H.
Published: June 2005

This study presents a cinefluoroscopic and electromyographic analysis of the feeding behavior of squab during regurgitation feeding. Two phases are distinguished in this behavior: the gaping phase, in which the squab holds its beak wide open while the parent compresses its crop; and the snapping phase, in which the squab opens and closes its beak several times while the parent raises its head. Unlike adult food uptake, the transport of food in squab occurs passively, using the flow in the crop contents which is caused by the compression of the crop of the parent. This feeding behavior does not change when squab grow older, but on average the duration of the gaping phase increases and the duration of the snapping phase decreases. Even squab of 19 days old, which are capable of independent feeding, display the same type of feeding behavior when they feed from the crop of the parent. A gradual transition from ontogenetic feeding to adult feeding or drinking behaviour is not observed, neither in movement patterns. nor in EMG patterns. © 1994 Wiley‐Liss, Inc.
Sex ratios of sea turtles
Authors: Mrosovsky N.
Published: June 2005

Estimates of sex ratios of hatchling sea turtles range from approximately 50% female (Chelonia mydas and Dermochelys coriacea in Suriname) to approximately 90% female (Caretta caretta in Florida). Seasonal sex production profiles (SSPPs) show how similar overall sex ratios can be achieved in dissimilar ways. Possible explanations of the data include sampling error, constraints on evolutionary adjustment of pivotals or behavior to local thermal conditions, and violations of assumptions required by classical Fisherian theory. © 1994 Wiley‐Liss, Inc.
Sex‐determining mechanisms in squamate reptiles
Authors: Viets Brian E. , Ewert Michael A. , Talent Larry G. , Nelson Craig E.
Published: June 2005

Two modes of sex determination occur in squamates: genotypic sex determination (GSD) and temperature‐dependent sex determination (TSD). Within each of these two major modes, there are many different variants, or mechanisms. Male heterogamety, female heterogamety, multiple sex chromosome systems, and homomorphic sex chromosome systems are all types of GSD found in squamates. Two patterns of TSD have been reported.

Only three snakes have been investigated for their sex‐determining mechanisms, each having GSD, although incubation temperature does cause differential mortality and affects post‐hatching physiology. Less than 50 lizard species have been investigated, but there is considerable diversity in the sex‐determining mechanisms reported thus far. Apparently, TSD (and/or GSD) has evolved multiple times within a given taxon. Presently, both GSD and TSD are found in the Agamidae, Eublepharidae, and Gekkonidae, and possibly in the Iguanidae, Lacertidae, and Varanidae as well. Only GSD has been reported for the Scincidae and Teiidae.

Correlations within the Eublepharidae suggest an adaptive explanation for the evolution of sexdetermining mechanisms; a shift from male‐larger dimorphism to female‐larger (or no sexual size dimorphism) is accompanied by a shift in sex‐determining mode. These shifts are in agreement with similar correlations observed in turtles. © 1994 Wiley‐Liss, Inc.
Sertoli cell differentiation and gonadogenesis in Alligator mississippiensis
Authors: Smith Craig A. , Joss Jean M. P.
Published: June 2005

Temperature‐dependent sex determination (TSD) was first described for a crocodilian in Alligator mississippiensis, in which egg incubation at 33°C produces 100% male hatchlings and incubation at 30°C produces 100% females. Ultrastructural signs of testis differentiation in embryos incubated at 33°C are first detected during days 28–34 (developmental stages 21–22), when small numbers of enlarged “presumptive” Sertoli cells (pre‐Sertoli cells) appear in the gonadal medulla of most embryos. These pre‐Sertoli cells proliferate and differentiate into Sertoli cells during stage 23 at 33°C (days 35–41), marking seminiferous cord formation. At 30°C, some pre‐Sertoli‐like cells are also present in the medulla, but they are less numerous than at 33°C and they do not differentiate into Sertoli cells. Ovary differentiation at 30°C is characterized by proliferation of cortical germs cells from day 39 (stage 22), closely followed by proliferation of somatic (pre‐follicular) cells in the cortex and regression of the medullary cords from day 43 (stage 23). We hypothesize that TSD in the alligator might be a function of a temperature‐derived mismatch between Sertoli cell differentiation and germ cell/cortex proliferation. © 1994 Wiley‐Liss, Inc.
Epidermal cell cycle and region‐specific growth during segment development in Artemia
Authors: Freeman John A.
Published: June 2005

During larval development in instar IV brine shrimp, segment 1 grew by cell replication and cell differentiation. Cell cycle analysis revealed that the cell cycle was synchronized with the molt cycle. Mitosis occurred late in the instar and S phase began at hr 6 of the following instar. Three populations of cells comprised the dorsal integument. The medial‐dorsal region did not grow. Cell enlargement occurred in the dorsal‐lateral population while cell replication took place in the lateral population. The limb bud (ventral surface) grew in width by replication in the distal population, and in height by enlargement of the general epidermal cells in the proximal population. Expansion of each region of the integument was proportional to the cell growth in that region. Moreover, both growth processes were dependent on the level of nutrients and were enhanced by diets enriched in polyunsaturated fatty acids. A nutrient‐dependent growth control point occurred in the G1 period. The commitment to replication and differentiation occurred by hr 2 of instar IV. The findings show that integumental growth is a result of regionspecific cell growth processes which are controlled by nutrients during the G1 period. © 1995 Wiley‐Liss, Inc.
Purification of the δ isoenzyme of protein kinase C from the hepatopancreas of the shrimp Penaeus monodon with phosphorylation on tyrosine residues
Authors: Huang Chein‐Fuang , Chuang Nin‐Nin
Published: June 2005

The δ isoenzyme of protein kinase C (PKC‐δ), purified from the plasma membrane of the hepatopancreas of the shrimp Penaeus monodon is specifically phosphorylated at tyrosine residues, as demonstrated by specific dephosphorylation by phosphotyrosyl protein phosphatase from the hepatopancreas of the shrimp Penaeus monodon. The specific activity of purified PKC‐δ was 200 units/mg of protein. The subunits of Mr 66,000, 62,000, and 58,000 of PKC‐δ were not autophosphorylated after the addition of phosphatidylserine and diolein. However, the purified PKC‐δ was active and catalyzed the phosphorylation of myelin basic protein. The kinase activity of the purified PKC‐δ could be decreased after treatment with phosphotyrosyl protein phosphatase. © 1995 Wiley‐Liss, Inc.
Effects of body size and thermal acclimation on parvalbumin concentration in white muscle of striped bass
Authors: Rodnick Kenneth J. , Sidell Bruce D.
Published: June 2005

Parvalbumin from anaerobic white skeletal muscle of striped bass (Morone saxatilis) was characterized and the hypothesis tested that parvalbumin concentration varies with body size and thermal acclimation. Two parvalbumin isotypes (molecular weights 8.7 and 10.3 kDa, with pIs of 4.63 and 4.90, respectively) were identified from whole‐muscle extracts by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE), immunoblotting with a monoclonal antibody specific for parvalbumin, and two‐dimensional PAGE of heat‐treated supernatants. Total concentrations of parvalbumin were exceptionally high, ranging from 5.2 to 12.3 mg·g−1 wet wt. or 0.55 to 1.29 millimoles per kg wet wt. of tissue. There was a significant inverse relationship between body size and total parvalbumin titer in white muscle (r = −0.89, P < .001), with small fish (<500 g body weight) having twofold more parvalbumin than large fish (>2 kg). However, only concentration of the 8.7 kDa isotype varied between animals of different size. Given that parvalbumin can bind two calcium ions with high affinity, the higher titer of parvalbumin in muscles of small fish may be partially responsible for a higher tail‐beat frequency and faster rate of muscle relaxation than in larger animals. Lower titers of parvalbumin also may prolong the active state of muscle contraction in large striped bass and promote higher muscle force production than in small animals. In contrast to the effects of body size on parvalbumin content, thermal acclimation at cold termperature (5°C) for 8–10 weeks did not change the concentration of parvalbumin in white muscle. © 1995 Wiley‐Liss, Inc.
Flagelliform or coronata glands of Nephila clavipes
Authors: Rodríguez Rosa , Candelas Graciela C.
Published: June 2005

The flagelliform or coronata glands of the orb‐web spider, Nephila clavipes, have been studied and compared to other silk‐producing glands from the organism. The glands, which produce silk for the double filament of the core thread in the sticky spiral, exhibit three distinct morphological areas: tail, sac, and duct. Electrophoretic separation of the solubilized contents of the glands yields an uppermost diffuse band of high molecular size, preceded by a stepladder of well‐defined peptides, which have been shown to be products of discontinuous translation in three other sets of glands. The luminal contents do not migrate as a discrete and well‐defined band as those of the other glands, but rather as a diffuse area, typical of glycosylated proteins. Fibroin synthesis is stimulated by the mechanical depletion of the organism's stored silks, as in other Nephila glands, judged by the increased intensity of the bands and also by the structural alterations seen in cross sections of the glands' tails. © 1995 Wiley‐Liss, Inc.
Blood volume in the hemoglobinless Antarctic teleost Chionodraco hamatus (Lönnberg)
Authors: Acierno R. , MacDonald J. A. , Agnisola C. , Tota B.
Published: June 2005

Blood volume in the hemoglobinless Antarctic icefish Chionodraco hamatus (Channichthyidae) has been determined by the Evans blue dye dilution technique. A mean blood volume of 127.0 ± 5.0 ml kg−1 body weight was found, a value even higher than that previously found in another icefish, Chaenocephalus aceratus (mean blood volume, 89.7 ml kg−1 body weight; Hemmingsen and Douglas [1970] Comp. Biochem. Physiol., 33:733–744; Twelves [1972] Br. Antarct. Surv. Bull. 37:85–92). This extraordinary hypervolemia appears unique among teleosts and may compensate for the absence of hemoglobin in the icefish. © 1995 Wiley‐Liss, Inc.
Effects of all‐trans retinoic acid on regenerating limbs of the fiddler crab,Uca pugilator
Authors: Hopkins P. M. , Durica D. S.
Published: June 2005

Regeneration of walking legs in the fiddler crabUca pugilatorrepresents true epimorphic growth since it involves organization of an undifferentiated blastema prior to regrowth of a new limb. Normal regeneration inUcaconsists of two major stages—basal growth and proecdysial growth. One of the earliest events in the basal growth stage of regeneration is the secretion of cuticle by epidermal cells that migrate under the scab at the site of limb loss. When crabs are maintained in a 0.05 mM emulsion of retinoic acid (RA) in sea water during the first 2 weeks following autotomy, the pattern of cuticle secretion is disrupted in many limb buds. Limb buds on RA‐treated crabs grow more slowly and are frequently malformed. © 1995 Wiley‐Liss, Inc.
Involvement of cAMP in inhibition of maturation of follicle‐enclosed oocytes by actinomycin D in Xenopus laevis and Rana temporaria
Authors: Skoblina M. N. , Matikainen T. , Huhtaniemi I.
Published: June 2005

Production of estradiol‐17β and cAMP was assayed during maturation of the follicle‐enclosed oocytes of Xenopus laevis and Rana temporaria stimulated by pituitary suspension or hCG, correspondingly. In some samples, the nuclear function was suppressed by pretreatment with AD. The level of estradiol‐17β in the oocytes of the both species was very low and was not affected by hormonal or AD treatment, while the level of cAMP (follicle + medium) increased. When maturation was stimulated by low concentrations of gonadotropic hormones inducing complete or near 100% maturation, the cAMP level increased 1.4‐ to 3.9‐fold. Both higher concentrations of the gonadotropic hormones and pretreatment of the follicles with AD increased the cAMP level still more. Combination of these treatments led to a greater increase of cAMP and to inhibition of oocyte maturation. We conclude that cAMP, rather than estradiol‐17β, is involved in the AD‐induced inhibition of amphibian oocyte maturation stimulated by gonadotropins. © 1995 Wiley‐Liss, Inc.
Temperature and sex chromosomes govern sex ratios of the mouthbrooding Cichlid fish Oreochromis niloticus
Authors: Baroiller Jean François , Chourrout Daniel , Fostier Alexis , Jalabert Bernard
Published: June 2005

Up to now, temperature sex differentiation has been demonstrated in a single fish species, Menidia menidia. This study analyzes this hypothesis in Oreochromis niloticus. Treatments at 36°C, covering the hormone sensitive period, increased the proportion of males (33% to 81%). The male proportion was affected by treatments starting not later than 13 days after fertilization and lasting 10 days or more. Survival rates were not affected by treatments. Functional masculinization of genetic females was demonstrated by the sex‐ratio analysis of 10 temperature‐treated males. Sex reversal by temperature treatment was also confirmed on a genotypic female population. The response to temperature strongly depends upon the breeding pairs. High temperatures override sex chromosome influence in Oreochromis niloticus. Therefore, Oreochromis niloticus sex is determined by genetic factors, temperature level, and genotype‐temperature inter‐actions. Temperature‐dependent sex differentiation may occur more frequently in fish than previously thought, despite the presence of functional sex chromosomes. © 1995 Wiley‐Liss, Inc.
Role of pyriform cells during the growth of oocytes in the lizard Podarcis sicula
Authors: Motta C. M. , Scanderbeg M. Castriota , Filosa S. , Andreuccetti P.
Published: June 2005

In order to clarify the role of follicle cells during growth of previtellogenic oocytes in lizards, an ultrastructural and autoradiographic investigation was carried out in Podarcis sicula. The evidence obtained clearly indicated that both intermediate and pyriform cells are actively involved in the synthesis of RNA that is then transferred to the oocyte, via intercellular bridges, apparently together with a variety of cytoplasmic organelles. At the end of the previtellogenic phase of growth, during the regression of the epithelium, the rate of synthesis of RNA in follicle cells is reduced, in particular in the nucleolus, but the flow of materials toward the oocyte continues. Thus, the intermediate and pyriform cells should be regarded as nurse cells even though they have characteristics rather different from those of the nurse cells described in other animals, such as insects. © 1995 Wiley‐Liss, Inc.
Characterization of zebra mussel (Dreissena polymorpha) sperm morphology and their motility prior to and after spawning
Authors: Mojares J. J. , Stachecki J. J. , Kyozuka K. , Armant D. R. , Ram J. L.
Published: June 2005

In order to understand more about the reproductive physiology of the zebra mussel (Dreissena polymorpha), we have examined the effect of spawning on the kinematics and fertilization ability of their spermatozoa. Sperm morphology was characterized using scanning electron microscopy, differences in sperm kinematics were examined using CASA following manual collection of sperm from the gonad or spawning induced by 5‐hydroxytryptamine (5‐HT), and the fertilization ability of spawned and manually removed spermatozoa were compared. D. polymorpha sperm have a tail 50 μm long, a midpiece consisting of four spherical mitochondria‐rich regions approximately 0.6 μm in diameter, a conical nucleus 2.52 μm in length, and a cylindrical acrosome 0.72 μm in height and width. Kinematic analysis revealed that manually removed sperm exhibit significantly lower motion characteristics as compared to spawned sperm. Treatment with 5‐HT had no significant effect on the sperm kinematics of either manually removed or spawned spermatozoa. These data suggest that D. polymorpha spermatozoa have a similar morphology to other bivalve sperm, spawning results in a significant enhancement in sperm kinematics, and 5‐HT does not directly alter sperm motion. © 1995 Wiley‐Liss, Inc.
Restriction of cell fate of superficial cells in the marginal zone of the amphibian embryo Pleurodeles waltl
Authors: Delarue Michel , Sáez Francisco J. , Johnson Kurt E. , Boucaut Jean‐Claude
Published: June 2005

The fate of circumblastoral cells has been studied in the Pleurodeles waltl late blastula and early gastrula. Individual superficial cells were labeled in defined regions with a fluorescent cell lineage tracer. Labeled progeny were located in sectioned tail bud stage embryos. The injection of defined cells at different developmental stages allowed us to compare the fates of superficial cells in similar locations in late blastula and early gastrula stages and thus to study the restriction of developmental fate. A progressive spatial and temporal restriction of cell fate was observed when comparing clones of cells derived from an injected blastula stage cell and an injected gastrula stage cell. At the blastula stage, the dorsal and dorsolateral regions contain few cells already restricted in their developmental fate to a single mesodermal organ. In contrast, at the gastrula stage, most cells in the dorsal and dorsolateral regions give rise to a single mesodermal derivative, whereas ventrolateral and ventral cells still form mesodermal derivatives but also form ectodermal and endodermal derivatives. © 1995 Wiley‐Liss, Inc.
Antibacterial activity in the blood cells of the solitary ascidian, Ciona intestinalis, in vitro
Authors: Findlay Cameron , Smith Valerie J.
Published: June 2005

The antibacterial properties of the blood cells of the solitary ascidian, Ciona intestinalis, were investigated in vitro. The results show that blood cell lysate supernatants have potent antibacterial activity against a wide range of bacteria. Activity was strongest against Gram positive bacteria, where typically there was a 95‐99% reduction in bacterial viability within 1 h. By contrast, Gram negative bacteria were less susceptible to the antibacterial effects, with the viability of these bacteria generally reduced by approximately 20‐40% after 3 h. Activity against both types of bacteria was further found to be heat‐stable (even after heating to 100°C for 10 min or freezing to −20°C for up to 1 month), Ca2+‐but not Mg2+‐dependent, and active at very low titres. Comparison of the antibacterial vigour of lysate supernatants made from separated blood cell populations revealed that activity resides mainly in the morula cells with some, albeit weaker, activity also detectable in the hyaline amoebocytes. No activity was present in the plasma. Preliminary investigations into the mode of action of the active factors indicate that the response is not due to lysozyme, is not directly lytic in character, and is not attributable to agglutination. Instead, as preliminary characterization by gel filtration on Sephadex G‐75 revealed 4 main protein peaks, with antibacterial activity confined to peak 3 (molecular weight range of 8‐15 kDa), the phenomenon seems to be due to the action of one or more low molecular weight proteins. The location, action, and release of these factors appear to differ from those of the cecropins and defensins described in other animal groups. © 1995 Wiley‐Liss, Inc.
Occurrence and hormonal action of ecdysone on gametogenesis and energy utilization in the leech Nephelopsis obscura (Erpobdellidae)
Authors: Kalarani V. , Reddy D. C. , Habibi H. R. , El‐Shimy N. , Davies Ronald W.
Published: June 2005

The present study provides novel information on the presence of compounds with ecdysone‐like activity and its involvement in the control of gonadal development in a leech. The presence of ecdysone was demonstrated in leech (Nephelopsis obscura) extract by means of high‐performance liquid chromatography (HPLC) in combination with radioimmunoassy. Leech extract was found to bind specifically to an anti‐ecdysone antiserum in a similar manner as standard ecdysone. Further HPLC purification demonstrated the presence of an immunoreactive fraction coeluting exactly with the standard ecdysone, strongly suggesting the presence of ecdysone in N. obscura. Addition of ecdysone to the ambient medium not only advanced leech gametogenesis but also influenced energy utilization. Both low (60 μg·L−1) and high (600 m̈g·L−1 concentrations of ecdysone increased testisac number, spermatogonia, 4th stage spermatogonia, ovisac size, and 2nd stage oogonia within 14 days compared to 35 days in the controls. Ecdysone also caused significant decreases in glycogen, total lipid, and triacylglycerols correlated with the energetic demands of gametogenesis. The findings provide support for the hypothesis that endogenous ecdysone is involved in the regulation of reproduction in N. obscura. © 1995 Wiley‐Liss, Inc.
Prospects for using retroviral vectors for human gene therapy
Authors: Yee Jiing‐Kuan
Published: June 2005

Most of the approved clinical trials of human gene therapy are based on vectors derived form retroviruses. For some retroviruses, such as murine leukemia virus, the life cylcel and means of gene regulation are well understood, and provirus sequences have been cloned. Cell lines that allow the generation of high‐titer retroviral vectors without helper virus contamination have been established. Vectors generated from such cell lines are infectious and can efficiently deliver the gene of interest into the target cells. Because virus‐specific genes are deleted from these vectors, further spread of the vectors is prevented. Retrovirus‐mediated gene transfer has been tested in human clinical trials for the treatment of the inherited deficiency of adenosine deaminase and the inherited deficiency of low‐density lipoprotein receptor. Preliminary results from both trials demonstrate the feasiblility and potential efficacy of using gene therapy to treat human diseases. © 1995 Wiley‐Liss, Inc.
Development of adenovirus vectors for gene therapy
Authors: Sharma Sanjai , Tozer J. R.
Published: June 2005

The development of methods for human gene therapy will require efficient and stable introduction of foreign gene into somatic cells. A number of gene transfer technologies are being developed that have the potential for therapeutic application to illnesses such as cancer, genetic diseases, and infectious diseases [Mulligan, 1993]. Viruses have been used in many early gene therapy model studies. Indeed, recombinant adenoviruses are one of the most promising gene transfer systems currently available. Adenovirus vectors are used in about 10% of all the gene therapy protocols approved by the recombinant advisory committee. This review focuses on the development of adenovirus vectors, their use in clinical settings, and current obstacles to prolonged gene expression. © 1995 Wiley‐Liss, Inc.
Transplantation of neural progenitor and stem‐like cells as a strategy for gene therapy and repair of neurodegenerative diseases
Authors: Snyder Evan Y. , Flax Jonathan D.
Published: June 2005

Potential new approaches to central nervous system (CNS) dysfunction have been created by the convergence of neural progenitor and stem cell biology with gene therapy and repair. Neural progenitors can be maintained in a proliferative state in vitro through retroviral transduction of an immortalizing gene. The immobilized progenitors then appear to behave much like normal CNS stem cells and hence have been termed stem‐like cells. The ability to transplant clonally related neural progenitors that self‐renew in culture but, after transplantation to the brain, differentiate appropriately into neurons and gila, may not only facilitate developmental inquiries, but also circumvent the limitations of primary fetal tissue for neural grafting. These cells are homogenous, abundant, and well‐characterized. They may express therapeutic gene products intrinsically or be readily engineered ex vivo to do so their ability to integrate efficiently into germinal zones and to migrate make possible transplant techniques that ensure widespread engraftment. Exploiting the inherent properties of neural progenitors, which allow them to become integral members of normal structures throughout the host brain, may allow foreign gene products to be delivered in a sustained, direct, and perhaps regulated fashion without disturbing other neurobiological processes. Transplants of such stem‐like cells may make possible new strategies for gene therapy and repair of the CNS, including the replacement of degenerated cells, the engineering of donor cells to be resistant to toxins, the delivery of missing metabolic or other gene products, to the over‐expression of molecules, and the substitution of alternate metabolic pathways. These approaches appear to be successful in various mouse models of neurodegeneration. Such observation may also provide a paradigm for the therapeutic use of stem cells from other organ systems. © 1995 Wiley‐Liss, Inc.
Clinical trials of D1 and D2 dopamine modulating drugs and self‐injury in mental retardation and developmental disability
Authors: Schroeder Stephen R. , Hammock Ron G. , Mulick James A. , Rojahn Johannes , Walson Philip , Fernald Will , Meinhold Patricia , Saphare Geeta
Published: June 2005

We review the rationale for conducting clinical trials of D1 and D2 dopamine modulators for self‐injurious behavior (SIB) among people with mental retardation and developmental disabilities. We include a brief history of the relevant behavioral research on SIB, the psychopharmacology of neuroleptic drugs for SIB, pharmacotherapy for SIB based on dopamine function, treatment for SIB with neuroleptics, SIB and dopamine supersensitivity, and the D1 dopamine hypothesis and SIB. We also present controlled case studies of the use of clozapine to treat chronic, refractory SIB in three individuals with profound mental retardation. One was a dramatic responder at 225 mg per day; one was a partial responder at 300 mg per day; and one showed a decrease in stereotypy, but not SIB, at 100 mg per day. Studies from rats, monkeys, and humans support the hypothesis that the D1 dopamine receptor system in the nigrostriatal pathway of the basal ganglia plays a key role in SIB in some cases. © 1995 Wiley‐Liss, Inc.
The fragile X mutation
Authors: Imbert Georges , Mandel Jean‐Louis
Published: June 2005

Fragile X syndrome, the most common cause of inherited mental retardation, is the result of unstable expansions of a CGG repeat located in the 5′ untranslated region of the FMR1 gene. Normal alleles consist of 6‐50 CGG repeats, in general interspersed by 1–3 AGGs. Moderate expansions up to 200 repeats, called premutations, are found in phenotypically normal carrier males or females. When transmitted by a female, a premutation has a risk of up to 100% of further expansion to an abnormally methylated full mutation (230 to >1,000 CGGs), which results in shut‐down of FMR1 expression. In contrast, affected males with a full mutation carry a premutation in their sperm that is transmitted to their daughters. On maternal transmission, the timing of the transition from premutation to full mutation remains unsolved. It is generally believed, but has not been proven that this is a postzygotic event, in which case an imprinting mechanism is required to distinguish a premutation carried on a maternal or paternal X chromosome. As in other trinucleotide expansion diseases, linkage disequilibrium between the fragile X mutations and haplotypes of adjacent polymorphisms has been found in various populations, indicating founder effects. These studies have suggested that normal alleles that carry long perfect CGG repeats may constitute alleles that are predisposed to multistep expansion over many generations. The ability to detect the various types of mutations has revolutionized the diagnosis of the disease and genetic counseling, and should allow more precise estimates of the population frequency of the fragile X syndrome. It may also allow screening for carrier females in the general population. We discuss possible mechanisms of expansion in light of the unusual structural properties proposed for CGG repeats. Various other folate‐sensitive fragile sites that are also caused by unstable expansions of CGG (CCG) repeats are being cloned and characterized. In particular, methylated expansions at the FRAXE locus appear to be associated with mild mental retardation. © 1995 Wiley‐Liss, Inc.
The neurobiology of fragile X syndrome
Authors: Abrams Michael T. , Reiss Allan L.
Published: June 2005

Fragile X syndrome, the leading known cause of heritable mental retardation, is associated with mutations of the FMR1 gene on the X chromosome. Neurobiological research has characterized several gene‐brain‐function correlations in fragile X syndrome, although no complete pathogenic mechanisms have yet been elucidated. This report summarizes current knowledge of the neurobiology of fragile X syndrome. Published research findings are presented along with a discussion of the relevance of neurobiological data to the neurobehavioral phenotype and genetic mechanisms associated with the FMR1 mutation. © 1995 Wiley‐Liss, Inc.
Adaptive behavior in males with fragile X syndrome
Authors: Dykens Elisabeth M.
Published: June 2005

Adaptive behavior has long been a key component of the definition of mental retardation. However, research on these important skills in fragile X and other genetic syndromes is just under way, having taken a back seat to studies using mixed etiologic groups. Further, adaptive behavior is complex, and measurements of these skills must have a developmental orientation, apply to multiple life settings, and reflect typical as opposed to optimal performance. After reviewing these features, this article highlights three areas of adaptive functioning in males with fragile X syndrome: profiles, trajectories, and adaptive behavior‐IQ relations. Many males with fragile X show relative strengths in domestic and personal chores of daily living, or so‐called “practical” intelligence. Whereas age‐related gains in adaptive skills are often seen in boys, particularly during the preschool years, adolescents and adults seem to have relative stable adaptive age scores and declines in adaptive standard scores. Such developmental courses may parallel the IQ trajectory often seen in males with fragile X syndrome. The need for further adaptive research is emphasized, particularly in light of the critical role these skills play in the ultimate life success of individuals with mental retardation. © 1995 Wiley‐Liss, Inc.
Further observations on the teratogenic action of the thyroid stimulating hormone
Authors: Beaudoin Allan R.
Published: June 2005

Pregnant Wistar Albino rats were injected intraperitoneally with the thyroid stimulating hormone (TSH), obtained from several different suppliers, and with the dye trypan blue. Twenty USP units of TSH were injected on days 7 to 10 of pregnancy, one quarter of the total dose each day. Trypan blue was injected as a single subteratogenic dose (0.6 mg/100 gm maternal body weight) on day 8. Autopsy was on day 20. Some TSH prepared as a pituitary extract possessed very weak teratogenic activity, possibly limited to the production of hydronephrosis and hydroureter. Other TSH samples similarly prepared had no embryotoxic or teratogenic effect. Thyrotropin prepared from bovine serum exhibited distinct teratogenic activity causing the production of various malformations in the offspring of treated mothers. A subteratogenic dose of trypan blue enhanced the teratogenic activity of the serum prepared TSH sample but had no effect on TSH prepared from pituitary glands. The results of this experiment suggest that there is something in the nature of preparation of TSH from bovine serum that causes it to possess teratogenic activity.
Studies of the development of congenital anomalies in embryos of riboflavin‐deficient, galactoflavin fed rats. I. Growth and embryologic pathology
Authors: Shepard Thomas H. , Lemire R. J. , Aksu O. , Mackler Bruce
Published: June 2005

Embryos from maternal rats maintained on a riboflavin‐deficient, galactoflavin‐augmented diet were compared by gross and histologic examinations with normal controls. On day 11 of gestation no differences were noted between control and treated embryos; on days 12 and 13 the treated embryos were smaller in overall size; and on day 14 the rate of differentiation of tissues of the treated embryos was delayed.

The embryonic mortality occurred between day 11 and day 15. Serial sections of day‐14 treated embryos consistently contained extensive areas of necrosis in the mesoblast of the extremities and first branchial arch. A less frequent but similar lesion was found in the central nervous systems in two of four treated embryos examined on day 14. The pathologic lesion resembles the normal cell death which is part of the sculpturing process of developing extremities, but was of much greater magnitude. In addition, studies of sections of the extremities of the treated day‐14 embryos demonstrated a reduction in the number of cellular mitoses. By day 15 the necrosis had disappeared, the mode of clearing presumably being due to macrophage action as evidenced by photographs and by the presence of acid phosphatase‐containing cells in the areas of phagocytosis.

In the early stages of mesenchymal condensation the treated specimens evidenced digital fusion but measurements of the relative total volume of mesenchyme were similar in treated and control specimens.

Histochemical studies of the treated embryos but not the placentas or maternal tissues demonstrated an overall decrease in the reactions for succinic dehydrogenase from day 12 to day 17. Levels of malic and lactic dehydrogenases and alkaline and acid phosphatases were not decreased in the treated embryos when measured histochemically.
Failure of muscle relaxants to produce cleft palate in mice
Authors: Jacobs Richard M.
Published: June 2005

This study was designed to examine the validity of the theory that descent of the tongue, which is presumably induced by fetal muscular movements, is essential for normal closure of the secondary palate in mice. Nulliparous CD1 mice were given the following “muscle‐paralyzing” agents on day 13° of gestation, i.e., 1 day before the onset of the critical period of palate closure: d‐tubocurarine chloride, gallamine triethiodide (Flaxedil), phenobarbital sodium, chlorphenesin carbamate (Maolate), and ethyl ether. The full paralytical effect of each drug was maintained for 42 hours, i.e., until day 15 1/3 of gestation, by means of subsequent fractional doses. Various combinations of barbiturates, anesthetics, and muscle relaxants were also employed. All litters were recovered by laparotomy on day 15° of gestation. The presence of fetuses that were flaccid, limp, apneic, and unresponsive to stimulation was accepted as evidence of transplacental passage of the employed compounds. No cleft palates were found in 656 recovered fetuses. This may be viewed as an indication that muscular activity — either spontaneous or reflexogenic — is not essential for normal closure of the secondary palate in mice.
Fetal infections of hamsters, rats, and mice induced with the minute virus of mice (MVM)
Authors: Kilham Lawrence , Margolis George
Published: June 2005

Transplacental infections with MVM were studied in hamsters, rats, and mice. The most striking infections were in hamsters in which infected fetuses developed high titers of virus, then died, and were resorbed. Only a few fetuses out of each litter became infected, the majority remaining alive, well, and free of infection. The situation in pregnant mice, which are natural hosts of this agent, was different. In them parenteral inoculations produced no discernible effects on either mother or fetuses. But infected fetuses with high titers of virus were recovered from other females at term. In neither hamsters nor mice were instances found of placental infection unaccompanied by fetal infection. Why only a small percent of inoculated pregnant mice developed transplacental infections was not clear. Rats free of immunity and hence susceptible to parenteral inoculations were not found. Intrafetal inoculations of rats revealed, however, that MVM can proliferate in fetuses and then persist for weeks following birh without inducing detectable illness. Histologic studies revealed sparse but characteristic intranuclear inclusions in some animals but it was evident in others that MVM can be present in substantial titers in an absence of apparent histologic change. After direct inoculation of some rat and hamster fetuses generalized severe disease resulted, with replicating tissues being the major viral targets, as has been previously observed in infections with other intrauterine parvoviruses. Here large infectious doses were thought to be responsible for the special effects observed.
The effects of trypan blue on the blood pressure of rat embryos
Authors: Grabowski Casimer T. , Tsai Enoch N. C. , Chernoff Neil
Published: June 2005

The mean ventricular blood pressure (MVBP) of 141 control rat embryos and 164 embryos exposed to trypan blue was measured at 13.5, 14.5, 17.5, and 18.5 days of gestation. The mean pressure in the controls ranged from 19.7 mm water at 13.5 days to 62.7 mm at 18.5 days. The mean pressure of the treated embryos was the same as that of the controls at 13.5 days but about 10 mm lower at all other ages. The range of variation was much greater in experimental embryos than in controls. Many extremely low pressures were recorded in the treated embryos. The pressure differences between control and treated embryos were not due to any differences in rate of heart beat. Since the morphogenesis of the heart and major blood vessels is not completed until day 15.5, and because abnormal pressure and flow patterns can affect cardiovascular development, the abnormal pressures in the 13.5‐ and 14.5‐day groups possibly contribute to the high rate of cardiovascular anomalies induced by trypan blue. The abnormal pressures in the older age group are probably reflections of this heart damage.
The teratogenic response of mouse embryos to 5‐bromodeoxyuridine
Authors: Skalko Richard G. , Packard David S. , Schwendimann Robert N. , Raggio John F.
Published: June 2005

Pregnant ICR mice were administered single intraperitoneal injections of 300, 400, or 500 mg/kg of the thymidine analogue 5‐bromodeoxyuridine during the period of major organogenesis (days 7–11, Witschi stages 12–25). All dosages were teratogenic. The spectrum of malformations present on day 18 followed a definite stage‐dependency. Exencephaly with associated micrognathia and open eyelid were produced only by treatment during the time the anterior neuropore is open (days 7 and 8) with a peak on day 7. Polydactyly was produced by treatment on days 7 through 10 with a peak on day 9; while cleft palate occurred after treatment on days 9 through 11 with a peak on day 10. Experiments with 3H‐BUDR demonstrated that label appeared in the DNA of embryos and maternal liver at a time when the embryo is susceptible to the teratogenic action of BUDR.
Workshop on monitoring of human mutagenesis
Authors: Sutton H. E.
Published: June 2005

On November 7–8, 1969 a workshop was held in Bethesda, Maryland for the purpose of considering methods of monitoring human populations for environmentally induced mutations. This workshop, sponsored by the National Institute of Environmental Health Sciences, had as participants Drs. Heinz W. Berendes, Barton Childs, Edward M. Cohart, James F. Crow, John H. Edwards, George B. Hutchison, Marvin Legator, Brian MacMahon, Robert W. Miller, James V. Neel, Margery W. Shaw, H. Eldon Sutton (Chairman), and Niel Wald. In addition there were a number of observers from interested government agencies. Members of the workshop considered the various possibilities for systems of monitoring, including, where possible, an estimate of costs as well as scientific benefits.

This report was submitted by members of the workshop to Dr. Paul Kotin, Director of the National Institute of Environmental Health Sciences, and does not represent official policy of that Institute. It is presented here because of the general interest in population monitoring for mutations as well as for other effects.
Techniques for prenatal neurosurgical operations on rat fetuses and for obtaining postnatal survivors
Authors: Demyer William , Baird Irene
Published: June 2005

Postnatal survivors were obtained after intrauterine neurosurgical lesions were made in fetal rats on the 14th–19th days of gestation. The operations included destruction of a hemispheric wall, unilateral destruction of a rhombic lip or of the nuclei gracilis and cuneatus, spinal cord transection, septal destruction, and optic enucleation. Of 1047 animals subjected to various neurosurgical operations 24% were recovered alive at term. A significant cause of fetal mortality and morbidity was drainage of amniotic fluid. In operations done before the 16th day of gestation, loss of fluid causes cleft palate in approximately 50% of the fetuses born alive. Animals with cleft palate die within hours of birth because they cannot nurse. Postnatal survivability of fetuses subjected to operations can be improved in several ways. Rat mothers vary greatly in handling and nursing their offspring and in their tendency to cannibalization. The experimenter can identify tolerant mothers, and they can be used to produce several litters of operated fetuses. Operations can be planned so that several operated and unoperated females deliver on the same day, so that when some operated females fail to deliver spontaneously many fetuses can still be recovered alive at cesarean section and cross‐fostered to unoperated mothers.