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Management of invasive fishes has relied heavily upon understanding their spatial distributions and habitat use at fine spatial scales to guide treatments and removals. In the USA, targeted removal is used in management of bigheaded carps (Hypophthalmichthys spp.) in the Mississippi River system to reduce invasion potential into the Laurentian Great Lakes from the upper Illinois Waterway. Our study tested factors linked to fine-scale spatial distributions of the most prevalent bigheaded carp species—silver carp (Hypophthalmichthys molitrix)—in the upper Illinois River to increase effectiveness of removal efforts. Bi-monthly mobile hydroacoustic sampling was conducted from 2017 to 2018 and paired with continuous environmental data collection in the two northern-most invaded reaches of the upper Illinois River. Model selection was used to describe habitat conditions associated with silver carp presence and density. Depth was the most consistent predictor of silver carp presence and density, with shallower depths consistently associated with higher abundance. During summer months, shallow areas in large backwater habitats with lower temperature and higher dissolved oxygen concentration held more silver carp. These results may help managers focus targeted removal efforts through time, increase harvest effectiveness, and reduce the potential for further invasion toward the Laurentian Great Lakes.

Offspring survival, cohort performance, and ultimately population dynamics are strongly influenced by maternal characteristics (e.g., fecundity), whereas paternal contribution is often considered limited to genetic-driven fitness of males through sexual selection. However, male contribution to reproductive success can be particularly influential in species exhibiting paternal offspring care. Polychlorinated biphenyls (PCBs) are widespread, persistent contaminants that can disrupt maternal reproductive processes and negatively affect offspring. In contrast, how PCBs affect paternal reproductive success is largely unknown, but could ultimately affect population dynamics. We examined the effects of lifelong PCB exposure on the reproductive processes of male fathead minnows (Pimephales promelas), a species exhibiting sole paternal offspring care, by examining endocrine-associated gene expression, testes histology, secondary sexual characteristics, courtship ability, offspring care, and offspring survival. PCBs minimized male secondary sexual characteristics, but did not affect gonadal end points or inhibit ability to court females. Fathers exposed to high concentrations of dioxin-like PCBs had changes in gene expression, reduced offspring care behavior, and higher embryo mortality, possibly due to fathers spending less time within nests and less frequently tending to embryos. Through complex interactions among gene expression, physical characteristics, and behavior, PCBs inhibit paternal reproductive success and have the potential to suppress population size.

Spatially-correlated abiotic and biotic conditions can potentially induce synchrony in the dynamics of disparate populations or species. However, such potential synchrony among species or populations may be tempered by dynamics operating at finer temporal and spatial scales, as well as species-specific responses to environmental conditions. We examined within- and among-species synchrony in year-class strength across 130 lakes in northern Indiana over 30 years to evaluate the relative scale of potential synchrony and its possible ecological mechanisms in five recreationally important fish species: black crappie (Pomoxis nigromaculatus), bluegill (Lepomis macrochirus), largemouth bass (Micropterus salmoides), redear sunfish (L. microlophus), and yellow perch (Perca flavescens). Bluegill and black crappie recruitment was significantly positively correlated when the species coexisted, and relative year-class strength of both species was positively related to mean annual wind speed. However, there were few other instances of recruitment synchrony between or within species, regardless of whether synchrony was assessed within or among lake systems. In addition, habitat similarity and regional weather patterns also played a limited and inconsistent role in shaping recruitment strength or synchrony in these small inland systems. These results suggest that fish recruitment dynamics in small, inland systems are most often a function of system-specific biotic interactions that mask limited input from broader climatological influences, and that understanding recruitment in small lakes will require examinations on appropriately fine spatial and temporal scales.

Ecologists often focus on summarized composition when assessing complex, multivariate phenotypes such as fatty acids. Increasing complexity in fatty acid composition may offer benefits to individuals that may not be recognized by assessing mean fatty acid identity. We quantified fatty acid identity and complexity in the egg and muscle of spawning female yellow perch (Perca flavescens (Mitchill, 1814)) exposed to three overwinter thermal regimes (4, 8, and 13 °C) to evaluate (i) thermal regulation of fatty acid complexity, (ii) fatty acid complexity and identity differences between female muscle and eggs, and (iii) relationships between fatty acid complexity and egg traits. Temperature did not alter fatty acid complexity in either tissue. Muscle contained an even distribution of 12 abundant polyunsaturated fatty acids (PUFA), while eggs exhibited a simpler phenotype of eight compounds. Fatty acid complexity in female muscle was positively correlated with potential indicators of egg quality, including size and lipid content. Preferential allocation of fatty acids to eggs by females likely contributed to a simple phenotype dominated by PUFA precursors and energy sources, while muscle represented a more complex fatty acid phenotype. Recognizing complexity could elucidate variation in reproductive condition among individuals, while identifying patterns in fatty acid allocation among populations.

Population dynamics and ecological effects of invasive fishes are affected by offspring survival to sexual maturity (recruitment). Recruitment is oftentimes determined by conditions experienced during early life, and winter conditions become increasingly influential as species invade north in temperate regions. Bighead Carp (Hypophthalmichthys nobilis) and Silver Carp (H. molitrix) have invaded mid-latitudes of North America and threaten to invade farther north. We conducted pond experiments and bioenergetic simulations to: (1) assess the effects of mild winters on juvenile Bighead Carp and Silver Carp at mid-latitudes; (2) determine how conspecific density affects juveniles during mild winters; and, (3) determine effects of increased winter severity at increasing latitudes. Both species displayed high overwinter survival (85%) in pond experiments. Bighead Carp grew in length (mean 2 mm) and maintained initial body mass and percent dry mass (index of energy content). Silver Carp maintained initial length and mass and remained in high condition (dry mass). Conspecific densities tested did not affect growth, condition, or survival. Simulations suggest juvenile Bighead Carp could energetically survive the longest, coldest winter simulated (48° latitude); however, energy reserves at the start of winter became increasingly important for survival as latitude increased. Bighead Carp and Silver Carp recruitment success at mid-latitudes is likely driven by non-winter factors. If these species invade farther north, winter severity may play a stronger role in offspring survival, recruitment, and population dynamics. However, warmer and shorter winters at high latitudes caused by climate change will minimize this potential bottleneck and increase chances of successful recruitment.

Knowledge of the spatial distributions and dispersal characteristics of invasive species is necessary for managing the spread of highly mobile species, such as invasive bigheaded carps (Bighead Carp [Hypophthalmichthys nobilis] and Silver Carp [H. molitrix]). Management of invasive bigheaded carps in the Illinois River has focused on using human-made barriers and harvest to limit dispersal towards the Laurentian Great Lakes. Acoustic telemetry data were used to parameterize multistate models to examine the spatial dynamics of bigheaded carps in the Illinois River to (1) evaluate the effects of existing dams on movement, (2) identify how individuals distribute among pools, and (3) gauge the effects of reductions in movement towards the invasion front. Multistate models estimated that movement was generally less likely among upper river pools (Starved Rock, Marseilles, and Dresden Island) than the lower river (La Grange and Peoria) which matched the pattern of gated versus wicket style dams. Simulations using estimated movement probabilities indicated that Bighead Carp accumulate in La Grange Pool while Silver Carp accumulate in Alton Pool. Fewer Bighead Carp reached the upper river compared to Silver Carp during simulations. Reducing upstream movement probabilities (e.g., reduced propagule pressure) by ≥ 75% into any of the upper river pools could reduce upper river abundance with similar results regardless of location. Given bigheaded carp reproduction in the upper Illinois River is presently limited, reduced movement towards the invasion front coupled with removal of individuals reaching these areas could limit potential future dispersal towards the Great Lakes.

Limiting the prevalence of invasive species is a global conservation priority. Invasive species can have varying ecosystem effects and responses to control throughout an invaded range, and removal near invasion fronts may inadvertently alter these characteristics. Bigheaded carp (bighead carp (Hypophthalmichthys nobilis Richardson) and silver carp (H. molitrix Valenciennes)) are invasive fishes from Asia invading North American freshwater ecosystems. We used mobile hydroacoustic surveys to examine bigheaded carp population characteristics from 2012 to 2015 across an invasion gradient in the Illinois River (USA), one of the most likely pathways to the Laurentian Great Lakes. These bigheaded carp species comprised 23–46% of fish community abundance and 45–78% of fish biomass across reaches, with lower contribution near the invasion front where intensive management by harvest occurs. Bigheaded carp prevalence in the community did not differ by habitat and comprised >50% of community abundance and biomass throughout the river for most size classes. We identified negative relationships between density and relative weight (an index of body condition) of bigheaded carp, suggesting evidence of potential density-dependent intraspecific competition. Efforts to reduce invasive species abundances near invasion fronts may reduce prevalence. However, this could inadvertently release individuals from density-dependent competition and could enhance reproductive potential, growth or movements. By employing a suite of control efforts, including continuous removal efforts (including novel approaches) and by limiting movements (e.g., utilizing roads, fences, dams), it may be possible to offset undesired consequences of increased condition.

The influence of food and ambient water on 2H and 18O isotopic composition in fish soft tissues, how growth affects tissue-specific composition, and relationships of isotope values within and among tissues are poorly known. We exposed age-0 largemouth bass (Micropterus salmoides) to ambient water and food with known δ2H and δ18O values for 65 days and analyzed liver and muscle for δ2H and δ18O levels. Liver δ2H but not δ18O was influenced by water isotopic concentrations and neither ratio was influenced by the isotopic composition of food. In contrast, water and food affected muscle δ2H, whereas muscle δ18O was only influenced by water isotopic values. We observed relationships between fish growth and muscle δ2H and δ18O, where increased growth led muscle to come closer into equilibrium with food and water isotope values, but found no relationships with growth and either liver δ2H or δ18O. Ratios of 2H and 18O were positively related within muscle and within liver of individuals, as were δ2H values between liver and muscle and δ18O values between tissues. Studies assessing 2H and 18O in temperate fishes should account for isotopic contributions from water and food and consider consequences of fish growth and timing of sample collection.

International audience; In humans, de novo truncating variants in WASF1 (Wiskott–Aldrich syndrome protein family member 1) have been linked to presentations of moderate-to-profound intellectual disability (ID), autistic features, and epilepsy. Apart from one case series, there is limited information on the phenotypic spectrum and genetic landscape of WASF1-related neurodevelopmental disorder (NDD). In this report, we describe detailed clinical characteristics of six individuals with WASF1-related NDD. We demonstrate a broader spectrum of neurodevelopmental impairment including more mildly affected individuals. Further, we report new variant types, including a copy number variant (CNV), resulting in the partial deletion of WASF1 in monozygotic twins, and three missense variants, two of which alter the same residue, p.W161. This report adds further evidence that de novo variants in WASF1 cause an autosomal dominant NDD.

Female yellow perch Perca flavescens exposed to three overwinter temperature regimes (4, 8 and 13° C) for 150 days spawned in markedly different proportions upon spring warming (37% of females in 4° C v. 64 and 91% in 8 and 13° C treatments, respectively), but exhibited no differences in fecundity, egg size or egg lipid content. Females held at 4° C also exhibited less within-clutch egg size variation than females held at 13° C. Moreover, eggs differed among temperature treatments in the overall proportions of 18 fatty acids, with the colder treatments resulting in potentially higher quality eggs containing more of the unsaturated fatty acids C16:1, C22:6-n3 and C18:2 cis. Female somatic condition also varied with temperature. Maternal somatic growth and protein content increased while lipid content decreased in 13° C compared to the colder treatments. There were, however, no differences among treatments in the fatty acid composition of maternal muscle. These results suggest that the temperatures experienced during winter may be less influential to P. flavescens egg size or number, which may exhibit relatively little plasticity in this species, but can alter both the number of females that spawn and the overall composition of eggs and maternal somatic tissues, which may have implications for future reproductive success.

Invasive bigheaded carps, genus Hypophthalmichthys, are spreading throughout the Mississippi River basin. To explore the efficacy of a consumer-based market (i.e., invasivorism) to manage them, we developed a conceptual model and evaluated three harvest approaches&mdash, direct contracted removal, volume-based incentives (&ldquo, fisher-side&rdquo, control), and set-quota harvest (&ldquo, market-side&rdquo, control). We quantified the efficacy of these approaches and potential population impact in the Illinois River. Contracted removal was effective for suppressing small populations at the edge of the range but cannot support a market. &ldquo, Fisher-side&rdquo, removals totaled 225,372 kg in one year. However, participation was low, perhaps due to reporting requirements for fishers. The &ldquo, set-quota approach removed &gt, 1.3 million kg of bigheaded carp in less than 6 months. Larger, older fish were disproportionately harvested, which may hinder the ability to suppress population growth. Total density declined in one river reach, and harvest may reduce upstream movement toward the invasion fronts. With sufficient market demand, harvest may control bigheaded carp. However, lack of processing infrastructure and supply chain bottlenecks could constrain harvest, particularly at low commodity prices. Given the geographical scale of this invasion and complicated harvest logistics, concerns about economic dependence on invasivorism that encourage stock enhancement are likely unmerited.

Although environmental DNA (eDNA) is increasingly being used to survey for the presence of rare and/or invasive fishes in aquatic systems, the utility of this technique has been limited by a poor understanding of whether and how eDNA concentrations relate to fish density, especially in rivers. We conducted a field study to systematically test whether the eDNA released by a model invasive fish, Silver Carp (Hypophthalmichthys molitrix), was related to the density of this species in a large river. We quantified fish density throughout the 460 km long Illinois River using hydroacoustic surveys at 23 sites while concurrently collecting 192 surface water samples for eDNA analysis. We found that Silver Carp numerical density and biomass density were positively and non-linearly related to eDNA concentration and detection rate. Both eDNA concentration (copy number) and detection rate increased rapidly as Silver Carp density increased but plateaued at moderate densities. These relationships could prove useful for estimating Silver Carp relative abundance in newly invaded locations where population numbers are low to moderate. Future studies should explore the causes of this nonlinear relationship as it would ultimately benefit aquatic species monitoring and management programs.

A variety of gears and analytical methods can be used to characterise lentic fish assemblages; however, the combined influence of gear type and analysis can affect conclusions about assemblage patterns. Fish assemblages sampled with night electric fishing, gillnets and trapnets from 153 lakes were evaluated using summary indices of species composition, pairwise community similarity comparisons and multivariate ordination. For a given amount of effort, electric fishing had the highest species richness, while gillnets had higher diversity and evenness. Pairwise comparisons between gears revealed that (1) richness was positively correlated among all gears, (2) diversity and evenness were generally not correlated across gears and (3) electric fishing and trapnets captured more similar species than all other pairwise comparisons. Gear-specific multivariate correlation and ordination revealed that gillnet and electric fishing samples more similarly characterised variation in assemblages among lakes, while trapnets characterised assemblages along different gradients of species composition. These results indicate that either electric fishing or trapnetting can be used when assessing shallow-water assemblages for diversity or evenness, gillnets and either electric fishing or trapnets should be used for whole-lake assessments, and either gillnets or electric fishing should be used when evaluating regionwide variation in lake assemblages.

Expanding round goby ( Neogobius melanostomus ) populations threaten many native species throughout the Great Lakes. The qualities that make a habitat suitable for round gobies are oftentimes considered as single factors (e.g., substrate type or dreissenid mussels). A more thorough understanding of the environmental characteristics related to round goby abundance can help identify habitats that are less susceptible to invasion. This study examined the habitat characteristics associated with round goby abundance in the Beaver Archipelago of Lake Michigan and the Les Cheneaux and Saginaw Bay regions of Lake Huron. Chemical and physical variables, zooplankton, macroinvertebrate, and fish assemblages were sampled from open water and wetland habitats. Gradients in habitat characteristics, determined using ordination analyses and diversity indices, were correlated with round goby catch per unit effort (CPUE) using fyke nets. Round goby CPUE in the Beaver Archipelago was positively related to increasing productivity and a more diverse fish community. Round goby CPUE at Les Cheneaux was related to wave disturbance and fish species associated with greater habitat complexity, though habitat type alone did not explain these relationships. In contrast, round goby CPUE in highly productive Saginaw Bay wetlands was very low where fish diversity was high and assemblages were dominated by littoral species tolerant of eutrophic conditions. Overall, CPUE was related to indices of biological productivity, with the direction of these relationships varying among regions. Areas with high productivity, including some wetlands, may be less hospitable for round gobies and could serve as refugia for native species.

Intersex is defined as the abnormal presence of both testicular and ovarian cells in gonads of gonochoristic animals. Its occurrence is widespread and reports on its presence in the gonads of vertebrates continues to increase. In this review, we use standardized terminology to summarize the current knowledge of intersex in gonochoristic fishes and amphibians. We describe the different indices that have been used to assess the severity of intersex and synthesize reports discussing the prevalence of intersex in relation to different types of pollutants. In addition, we evaluate the geographic distribution and chronology of the reported cases of intersex in fishes and amphibians, their pathological descriptions and severity and discuss species sensitivities. We also summarize molecular biomarkers that have been tested for early detection of intersex in wild populations and highlight additional biomarkers that target molecular pathways involved in gonadal development that require further investigation for use in the diagnosis of intersex. Finally, we discuss the needs for future research in this field. Copyright © 2015 John Wiley & Sons, Ltd.

Fluctuations in water temperature can have important physiological consequences for fishes. Effects of daily thermal cycles are well studied and can be beneficial, increasing prey consumption and growth rates when mean and maximum temperatures of the fluctuations are at or below the species' optimum temperature. While less studied, subdaily temperature fluctuations are also common in many aquatic habitats and can be caused by both natural and anthropogenic processes. We performed laboratory experiments to examine how two fish species (yellow perch, Perca flavescens, and walleye, Sander vitreus) with similar thermal preferences respond to chronic exposure to subdaily temperature variability. We selected temperature treatments that reflected observed thermal variation after examining water temperature data from multiple aquatic systems. We then separately exposed yellow perch and walleye to a stable 23 °C treatment and 12-h cycles of 23 � 2 ° Co r 23� 4 °C for 45 days. Adult yellow perch exposed to fluctuations of 23 � 4 °C over 12 h expressed higher consumption, growth and food conversion efficiency than fish experiencing stable 23 °C. Temperature fluctuations, though, resulted in mortalities and the development of skin ulcers in yellow perch that did not occur under stable temperatures. In contrast, the same 12-h temperature fluctuations did not result in mortalities or stress responses in juvenile walleye. Moreover, unlike yellow perch, growth rates of walleye were lower under 12-h temperature fluctuations compared with the stable 23 °C treatment. Our results indicate that species with similar thermal preferences can respond differently to the same subdaily temperature fluctuations.

Water temperature strongly affects aquatic ectotherms, as even slight temperature changes can have dramatic effects on physiological rates. Water bodies receiving industrial thermal discharges can undergo dramatic spatial and temporal changes in water temperature. To quantify effects on aquatic ectotherms, thermal habitat quality (bioenergetic growth rate potential; GRP) for zebra mussel, Dreissena polymorpha (Pallas), rusty crayfish, Orconectes rusticus (Girard), walleye, Sander vitreus (Mitchill) and smallmouth bass, Micropterus dolomieu (Lacepede) was estimated near two power plant thermal discharges on the Ohio River, USA, from 2010 to 2012 using bioenergetics models. These results were then compared with GRP under increased base temperatures representing climate warming. Growth rate potential for all species was low near the discharges during summer and highest in winter, with increasing prey consumption minimising the negative effects of increased temperatures. In their immediate vicinity, thermal discharges had a more adverse effect on GRP than plausible climate warming but primarily affected GRP over a small spatial area, particularly within 400 m downstream from the power plants. Examining thermal habitat suitability will become increasingly important as rising energy demand and climate change collectively affect aquatic organisms and their habitats.

It has been suggested that some Great Lakes coastal wetlands may be resistant to invasion by several non-indigenous species including round goby, Neogobius melanostomus . However, there is inconclusive evidence regarding how susceptible exposed fringing coastal wetlands, in particular, are to round goby invasion. Therefore, we quantified round goby catch per unit effort (CPUE) using fyke nets in the Beaver Archipelago of Lake Michigan, and the Les Cheneaux islands and Saginaw Bay regions of Lake Huron. In addition, we examined the influence of body size and maturity on round goby habitat use. Catch per unit effort from fyke nets was highest in the Beaver Archipelago, where wetlands were dominated by small, immature round gobies and open water habitats were dominated by large adults. Fyke net catches within Les Cheneaux sites were similar between habitats and differences in size and maturity were not observed. Conversely, very few round goby were captured in wetlands of Saginaw Bay where CPUE was moderate in open water. This indicates that some exposed fringing wetlands in the Great Lakes, specifically those with high productivity, could have a higher degree of resistance to round goby invasion.

There is a widely accepted paradigm supported by early field and laboratory observations that the adult round goby (Neogobius melanostomus) is highly adapted to, and primarily survives on, dreissenid mussels. However, more recent stable isotope and diet analyses indicate that the round goby may not rely on dreissenid prey to the extent that was previously believed. We conducted a feeding experiment where round gobies were provided with an excess of one of four naturally occurring diets for 25 days – dreissenid mussels, juvenile fish, chironomids, or zooplankton. Round gobies fed dreissenids had significantly lower growth (−0.04 g day−1) than individuals fed fish and chironomids (0.13 g day−1) and displayed the same weight loss as round gobies fed only zooplankton. Although dreissenids are often consumed by round gobies, this likely happens only when more profitable prey such as fish and non-dreissenid invertebrates are lacking or difficult to capture. Additionally, field observations of round goby diets t...

The molecular testing options available for the diagnosis of genetic disorders are numerous and include a variety of different assay platforms. The consultative input of molecular pathologists and cytogeneticists, working closely with the ordering clinicians, is often important for definitive diagnosis. Herein, we describe two patients who had long histories of unexplained signs and symptoms with a high clinical suspicion of an underlying genetic etiology. Initial molecular testing in both cases was negative, but the application of high-resolution array comparative genomic hybridization technology lead to definitive diagnosis in both cases. We summarize the clinical findings and molecular testing in each case, discuss the differential diagnoses, and review the clinical and pathological findings of Mowat-Wilson syndrome. This report highlights the importance for those involved in molecular testing to know the nature of the underlying genetic abnormalities associated with the suspected diagnosis, to recognize the limitations of each testing platform, and to persistently pursue repeat testing using high-resolution technologies when indicated. This concept is applicable to both germline and somatic molecular genetic testing.

Natural and human activities can result in both high temporal and spatial variability in water temperature. Rapid temperature changes have the potential to dramatically affect physiological processes in aquatic organisms and, due to their limited mobility, fish early life stages are particularly vulnerable to ambient temperature fluctuations. In this study, we examined how the magnitude and frequency of temperature fluctuations affect survival, growth, development, expression of thermoresponsive genes, and gonadal differentiation in fathead minnows, Pimephales promelas. We exposed individuals (0 to 4 days post fertilization) of known genotypic sex to fluctuations of Δ4 °C over 12-h, Δ8 °C over 12- and 24-h, and three stable temperatures (21, 25, and 29 °C) for up to 45 d. Expression of hsp70 in fish exposed to the highest-magnitude, highest-frequency fluctuating treatment cycled in concert with temperature and was upregulated initially during exposure, and may have contributed to temperature fluctuations having little effect on time to and size at hatching (whole-organism responses). This treatment also caused fish to undergo nondirectional sex reversal. These results indicate that hsp70 may be involved in mediating thermal stress from subdaily temperature fluctuations and that sex determination in fathead minnows can be influenced by cycling temperatures.

Sympatric congeners with similar physiological and morphological characteristics may appear to overlap in niche space but respond to environmental change in different ways leading to population decline of one species while the other remains stable. Understanding why sympatric congeners vary in their ecological success can be challenging, but is particularly necessary given the magnitude of human-induced environmental change among ecosystems. We propose that identifying a complex of subtle, interacting characters among congeners may be more effective in elucidating both historical coexistence and divergent ecological success in contemporary habitats compared to identifying just one apparent limiting similarity between species. Using this subtle difference hypothesis, we examined how metabolic rate associated with habitat use and internal and external morphology collectively influenced the ecological success of a common and a rare sturgeon species that differ dramatically in their conservation status due to environmental change. Multivariate analyses of gut morphology (e.g., intestine length) combined with respirometry on sand and gravel habitats were incorporated into a bioenergetics model to compare how the fishes responded to habitat change and food quality. Energetic tradeoffs induced by habitat type and underlying morphological differences led to different predicted growth rates. Compared with the more prevalent species, the rare and endangered fish needed to seek different habitats with less energetic costs and switch to foraging at a higher trophic level to persist. Our results corresponded to observed differences in ecological success between these species in the wild. Thus, subtle physiological and morphological differences may lead to dramatic differences in ecological success in contemporary habitats for species that are very similar ecologically.

Carnitine is an important nutrient that is present in the diet (particularly in meat and dairy products) and is synthesized from dietary amino acids. It functions to assist long-chain fatty acid metabolism and to regulate the ratio of free coenzyme A to acylcoenzyme A in the mitochondrion. Carnitine deficiency occurs in primary inborn errors of metabolism, in nutritional deficiency, and in various other disorders including antiepileptic drug therapy. Valproate therapy is often associated with decreased carnitine levels and occasionally with true carnitine deficiency. Some experimental and clinical evidence links valproate-induced carnitine deficiency with hepatotoxicity, but this evidence is limited and inconclusive. Carnitine supplementation has been useful in some studies, but these data are also limited. Young children with neurologic disabilities taking multiple antiepileptic drugs may have the greatest risk for carnitine deficiency. Measurement of carnitine levels appears warranted in these patients and in patients with symptoms and signs of possible carnitine deficiency. ( J Child Neurol 1991;6:7-14).

A full-term male infant exhibited rigidity of all extremities with hyperreflexia beginning soon after birth and lasting until his death at age 6 months. Head circumference remained at the 25th to 50th percentile. Distinct sleep-wake cycles and responsiveness to visual, auditory, and tactile stimuli developed. Metabolic studies, skin biopsy, electroencephalography, and electromyography produced normal results. Head computed tomographic and magnetic resonance imaging scans revealed mineralization of the basal ganglia and thalamus. Muscle and nerve biopsy results were consistent with axonal dystrophy. Autopsy showed widespread neuronal loss, with reactive gliosis, marked in the globus pallidus and brainstem reticulate core; spheroids in globus pallidus, nucleus cuneatus, and upper cervical cord; and mineralized neurons in the inner division of globus pallidus and thalamus. Neonatal hypertonia, rapid progression, and mineralization of the basal ganglia are unusual features of neuroaxonal dystrophy exhibited in this case. (J Child Neurol 1994;9:74-76).

To study the role of extravascular intracranial pressure (ICP) in the genesis of intracranial hemorrhage in the beagle puppy, we measured ICP in animals on the day of birth, untreated 3-day-old controls, and 3-day-old animals treated from birth with prolactin. Baseline ICP varied substantially in all 3 groups. Only 8% of this variability was attributable to variability in mean arterial pressure and central venous pressure. ICP was lower in the 3-day-old controls, animals at high risk for intracranial hemorrhage after a hypovolemic/hypotensive insult followed by rapid volume expansion, than in the other groups which are at lower risk. Administration of a hyperosmolar insult, intraperitoneal glycerol, to animals whose ICP was relatively high promptly lowered ICP. After this treatment, the risk of intracranial hemorrhage was markedly increased in these previously low-risk groups. We conclude that the normal neonatal decrease in brain water content and the consequent fall in ICP substantially increase the risk of intracranial hemorrhage in the beagle puppy, a model which appears similar in pathophysiology to hemorrhage in the preterm human infant.

After 72 h of cultivation on defined medium, mycelia of Allomyces macrogynus contain 36, 7.3, and 4.2% protein, lipid, and glycogen, respectively. Isolated and purified glycogen is water soluble and iodophilic and consists of at least 99% anhydroglucose. After partial hydrolysis of glycogen, maltose ( α -1,4-linkage) and isomaltose ( α -1,6-linkage) are the only detectable disaccharides. Absorption spectra of glycogen-iodine complexes are similar to those observed with glycogens from other organisms. The β -amylase hydrolysis limit (44–48%) and average chain length (11–12 glucose units) of the polysaccharide indicate that it is a typical glycogen. During starvation, as much as 48% of the stored glycogen is depleted while protein and lipid utilization is 45 and 25%, respectively. However, 72% of the dry weight loss during starvation occurs as a result of protein utilization. Glycogen from unstarved and starved mycelia shows no significant differences as judged by comparison of the iodine complex spectra, β -amylase limits, and average chain lengths. The quantity of a soluble galactose polymer increases more than twofold during starvation. Although the glycogen utilized during this period can easily account for the galactan increase, it is not known whether or not there is a direct relationship between these two polysaccharides. Although sporulation occurs during starvation, this work does not permit any definite conclusions regarding a relationship between sporogenesis and changes in the amounts of mycelial constituents.

We treated neonatal rabbits from birth with exogenous prolactin or the prolactin secretagogue fluphenazine. We compared the hydration at 72 h of skeletal muscle, skin, liver, and brain to that of untreated controls. Treatment did not change the water content of liver. It increased the water content of skeletal muscle, skin, and brain. However, the response to treatment differed among these tissues. In skin and skeletal muscle, the effect of treatment was most apparent in animals whose postnatal weight gain was relatively large. In contrast, treatment increased brain water content in all animals regardless of weight gain. We conclude that much of the early postnatal decrease in skin and skeletal muscle water is due to mobilization of the neonatal tissue water reservoir, and that prolactin appears to regulate that process. Changes in brain water between birth and 72 h of age appear to result from loss of reservoir water and possibly of cerebrospinal fluid offset in part by water accretion due to tissue growth.

Dry weight, protein, lipid, and glycogen were determined at various times during cultivation of the Chytridiomycetes, Rhizophydium sphaerotheca and Monoblepharella elongata. M. elongata had relatively stable levels of glycogen, but, in R. sphaerotheca, glycogen levels showed significant changes, particularly in older cultures in which a depletion of glycogen was accompanied by a marked thickening of the cell walls. Glycogen was a significant cellular constituent in both chytridiomycete species. In R. sphaerotheca and M. elongata, respectively, glycogen accounted for as much as 6% and 8.1% of the dry weight. In purified glycogens of both species, only alpha-1,4- and alpha-1,6-linked glucosyl residues were detected and the absorbance spectra of I2-complexes were similar to those of other well characterized glycogens. Purified Rhizophydium glycogen had a beta-amylolysis limit of 43%, and a CL of approximately 12. For the Monoblepharella polysaccharide, the respective values were 45% and 11. In extracts of the Oomycetes, Pythium debaryanum, Mindeniella spinospora, and Apodachlya sp., only beta-1,3- and beta-1,6-linked glucosyl residues were detected. These glucans were not iodophilic nor were they sensitive to alpha-amylase and beta-amylase. The properties of the oomycete polysaccharides suggested that they were similar to the mycolaminarans of Phytophthora spp. Although both investigated chytridiomycete species produced glycogen with typical properties, glycogen was apparently absent in the investigated Oomycetes.

Summary: We measured body hydration of healthy, term rabbit pups at birth and 72 hr of age. In addition, we measured hydration of individual tissues: skin, skeletal muscle, liver, and brain. At birth, the hydration of lean body mass, skin, and skeletal muscle, expressed as cc water per g fat-free dry weight (FFDW) was inversely proportional to birth weight. Low birth weight animals were significantly better hydrated than their larger littermates. During the first 72 hr of life, the nursing pups gained an average 31.39% of birth weight. Simultaneously, lean body hydration decreased by 23% (5.48 to 4.86 cc/g FFDW). The hydration change varied substantially among organs. The greatest loss occurred in skin (24%). Skeletal muscle lost 5.8%, and the brain lost 3.1%. When hydration at 72 hr was compared to weight gain and by inference fluid intake, a paradoxical result was obtained. Lean body, skin, and skeletal muscle hydration was inversely related to weight gain. The animals that gained the most weight retained the least water. In contrast, the hydration of brain and liver was significantly higher in animals that gained the most weight. We conclude that the newborn rabbit is endowed with a reservoir of fluid at birth, predominantly stored in skin and skeletal muscle. The rate of release of this store depends on fluid intake. It is rapidly lost if ample fluid intake is provided. In conditions of restricted fluid intake, the release is substantially slower. Speculation: At least two processes regulate tissue hydration in the newborn rabbit. The first, a function of growth, is responsible for the progressive accretion of intracellular water during gestation and postnatal development. It is illustrated by the increase in tissue hydration of brain and liver in well-nourished pups during the first 72 hr of life. The second process may be under hormonal regulation on a time scale of hr to days. It accounts for the relatively high level of tissue hydration at birth, and provides a supply of water and sodium to maintain plasma volume during the first days of life, thereby preventing dehydration during this period of variable fluid intake.

We measured serum and skeletal muscle electrolytes by flame photometry and muscle water by dessication in 45 rabbits on day 1 of life. Results are depicted graphically below. Tissue Na decreased with increasing birthweight (r=-0.61, p

We measured total body H2O content (ml/gm fat free dry weight) in neonatal rats from birth to 72 hours of age and compared these data with our earlier measurements in rabbits. At birth, H2O (in rats) was inversely correlated with birth weight (BW) (r=-0.408, p=.007) and it fell significantly between birth and 24 h (p

POSTNATAL CHAHGES IN SKELETAL MUSCLE AND SERUM SODIUM IN THE NEONATAL RABBIT PUP - EVIDENCE FOR AN INTRA-CELLULAR SODIUM RESERVOIR

1369 BARBITURATE ANAESTHESIA REDUCES THE INCIDENCE OF INTRAVENTRICULAR HEMORRHAGE (IVH) IN THE BEAGLE PUPPY