Northerly range expansion and first confirmed records of the smalltooth sand tiger shark, Odontaspis ferox, in the United Kingdom and Ireland

Three Odontaspis ferox (confirmed by mtDNA barcoding) were found in the English Channel and Celtic Sea in 2023 at Lepe, UK (50.7846, -1.3508), Kilmore Quay, Ireland (52.1714, -6.5937), and Lyme Bay, UK (50.6448, -2.9302). These are the first records of O. ferox in either country, and extend the species' range by over three degrees of latitude, to >52° N. They were ~275 (female), 433 (female), and 293 cm (male) total length, respectively. These continue a series of new records, possibly indicative of a climate change-induced shift in the species' range.

Centralized red muscle in Odontaspis ferox and the prevalence of regional endothermy in sharks

The order Lamniformes contains charismatic species such as the white shark Carcharodon carcharias and extinct megatooth shark Otodus megalodon, and is of particular interest given their influence on marine ecosystems, and because some members exhibit regional endothermy. However, there remains significant debate surrounding the prevalence and evolutionary origin of regional endothermy in the order, and therefore the development of phenomena such as gigantism and filter-feeding in sharks generally. Here we show a basal lamniform shark, the smalltooth sand tiger shark Odontaspis ferox, has centralized skeletal red muscle and a thick compact-walled ventricle; anatomical features generally consistent with regionally endothermy. This result, together with the recent discovery of probable red muscle endothermy in filter feeding basking sharks Cetorhinus maximus, suggests that this thermophysiology is more prevalent in the Lamniformes than previously thought, which in turn has implications for understanding the evolution of regional endothermy, gigantism, and extinction risk of warm-bodied shark species both past and present.

Somatic mutation rates scale with lifespan across mammals

The rates and patterns of somatic mutation in normal tissues are largely unknown outside of humans1-7. Comparative analyses can shed light on the diversity of mutagenesis across species, and on long-standing hypotheses about the evolution of somatic mutation rates and their role in cancer and ageing. Here we performed whole-genome sequencing of 208 intestinal crypts from 56 individuals to study the landscape of somatic mutation across 16 mammalian species. We found that somatic mutagenesis was dominated by seemingly endogenous mutational processes in all species, including 5-methylcytosine deamination and oxidative damage. With some differences, mutational signatures in other species resembled those described in humans8, although the relative contribution of each signature varied across species. Notably, the somatic mutation rate per year varied greatly across species and exhibited a strong inverse relationship with species lifespan, with no other life-history trait studied showing a comparable association. Despite widely different life histories among the species we examined-including variation of around 30-fold in lifespan and around 40,000-fold in body mass-the somatic mutation burden at the end of lifespan varied only by a factor of around 3. These data unveil common mutational processes across mammals, and suggest that somatic mutation rates are evolutionarily constrained and may be a contributing factor in ageing.

Novel Presentation of DMV-Associated Encephalitis in a Long-Finned Pilot Whale (Globicephala melas)

Cetacean morbillivirus (CeMV) is an important global cause of morbidity and mortality in cetacean populations, with four pathological presentations including non-suppurative encephalitis. We describe an unusual case of dolphin morbillivirus (DMV)-associated non-suppurative encephalitis in a long-finned pilot whale (Globicephala melas), in which the lesions were orientated on the periventricular white matter and comprised prominent multifocal syncytia formation in the absence of systemic lesions. DMV RNA was detected in brain tissue by qRT-PCR and immunohistochemistry for morbillivirus antigen yielded intense labelling of syncytia in periventricular sites, with sparse involvement of the deeper neuroparenchyma. The pattern of lesions raises the possibility of viral dissemination through the cerebrospinal fluid, as described for canine distemper virus, suggesting that similar pathogenic mechanisms may be implicated in lesion development. Further investigation is required to establish the pathogenesis of CeMV encephalitis and the behaviour of the virus within the central nervous system of cetaceans.

Reservoir frogs: seasonality of Batrachochytrium dendrobatidis infection in robber frogs in Dominica and Montserrat

Emerging infectious diseases are an increasingly important threat to wildlife conservation, with amphibian chytridiomycosis, caused by Batrachochytrium dendrobatidis, the disease most commonly associated with species declines and extinctions. However, some amphibians can be infected with B. dendrobatidis in the absence of disease and can act as reservoirs of the pathogen. We surveyed robber frogs (Eleutherodactylus spp.), potential B. dendrobatidis reservoir species, at three sites on Montserrat, 2011-2013, and on Dominica in 2014, to identify seasonal patterns in B. dendrobatidis infection prevalence and load (B. dendrobatidis genomic equivalents). On Montserrat there was significant seasonality in B. dendrobatidis prevalence and B. dendrobatidis load, both of which were correlated with temperature but not rainfall. B. dendrobatidis prevalence reached 35% in the cooler, drier months but was repeatedly undetectable during the warmer, wetter months. Also, B. dendrobatidis prevalence significantly decreased from 53.2% when the pathogen emerged on Montserrat in 2009 to a maximum 34.8% by 2011, after which it remained stable. On Dominica, where B. dendrobatidis emerged seven years prior to Montserrat, the same seasonal pattern was recorded but at lower prevalence, possibly indicating long-term decline. Understanding the dynamics of disease threats such as chytridiomycosis is key to planning conservation measures. For example, reintroductions of chytridiomycosis-threatened species could be timed to coincide with periods of low B. dendrobatidis infection risk, increasing potential for reintroduction success.

Reproductive Failure in UK Harbour Porpoises Phocoena phocoena: Legacy of Pollutant Exposure?

Reproductive failure in mammals due to exposure to polychlorinated biphenyls (PCBs) can occur either through endocrine disrupting effects or via immunosuppression and increased disease risk. To investigate further, full necropsies and determination of summed 25 polychlorinated biphenyls congeners (∑PCBs lipid weight) in blubber were undertaken on 329 UK-stranded female harbour porpoises (1990-2012). In sexually mature females, 25/127 (19.7%) showed direct evidence of reproductive failure (foetal death, aborting, dystocia or stillbirth). A further 21/127 (16.5%) had infections of the reproductive tract or tumours of reproductive tract tissues that could contribute to reproductive failure. Resting mature females (non-lactating or non-pregnant) had significantly higher mean ∑PCBs (18.5 mg/kg) than both lactating (7.5 mg/kg) and pregnant females (6 mg/kg), though not significantly different to sexually immature females (14.0 mg/kg). Using multinomial logistic regression models ΣPCBs was found to be a significant predictor of mature female reproductive status, adjusting for the effects of confounding variables. Resting females were more likely to have a higher PCB burden. Health status (proxied by "trauma" or "infectious disease" causes of death) was also a significant predictor, with lactating females (i.e. who successfully reproduced) more likely to be in good health status compared to other individuals. Based on contaminant profiles (>11 mg/kg lipid), at least 29/60 (48%) of resting females had not offloaded their pollutant burden via gestation and primarily lactation. Where data were available, these non-offloading females were previously gravid, which suggests foetal or newborn mortality. Furthermore, a lower pregnancy rate of 50% was estimated for "healthy" females that died of traumatic causes of death, compared to other populations. Whether or not PCBs are part of an underlying mechanism, we used individual PCB burdens to show further evidence of reproductive failure in the North-east Atlantic harbour porpoise population, results that should inform conservation management.

What caused the UK's largest common dolphin (Delphinus delphis) mass stranding event?

On 9 June 2008, the UK's largest mass stranding event (MSE) of short-beaked common dolphins (Delphinus delphis) occurred in Falmouth Bay, Cornwall. At least 26 dolphins died, and a similar number was refloated/herded back to sea. On necropsy, all dolphins were in good nutritive status with empty stomachs and no evidence of known infectious disease or acute physical injury. Auditory tissues were grossly normal (26/26) but had microscopic haemorrhages (5/5) and mild otitis media (1/5) in the freshest cases. Five lactating adult dolphins, one immature male, and one immature female tested were free of harmful algal toxins and had low chemical pollutant levels. Pathological evidence of mud/seawater inhalation (11/26), local tide cycle, and the relative lack of renal myoglobinuria (26/26) suggested MSE onset on a rising tide between 06:30 and 08∶21 hrs (9 June). Potential causes excluded or considered highly unlikely included infectious disease, gas/fat embolism, boat strike, by-catch, predator attack, foraging unusually close to shore, chemical or algal toxin exposure, abnormal weather/climatic conditions, and high-intensity acoustic inputs from seismic airgun arrays or natural sources (e.g., earthquakes). International naval exercises did occur in close proximity to the MSE with the most intense part of the exercises (including mid-frequency sonars) occurring four days before the MSE and resuming with helicopter exercises on the morning of the MSE. The MSE may therefore have been a "two-stage process" where a group of normally pelagic dolphins entered Falmouth Bay and, after 3-4 days in/around the Bay, a second acoustic/disturbance event occurred causing them to strand en masse. This spatial and temporal association with the MSE, previous associations between naval activities and cetacean MSEs, and an absence of other identifiable factors known to cause cetacean MSEs, indicates naval activity to be the most probable cause of the Falmouth Bay MSE.

Investigating links between polychlorinated biphenyl (PCB) exposure and thymic involution and thymic cysts in harbour porpoises (Phocoena phocoena)

The associations between polychlorinated biphenyls (PCBs) exposure and involution of lymphoid tissue and development of epithelial-lined cysts in the thymus of UK-stranded harbour porpoises (Phocoena phocoena) (n=170) were tested. Percentage of thymic lymphoid tissue (%TLT) was histologically quantified. Multiple regression analyses (n=169) demonstrated significant positive correlation between %TLT and nutritional status (p<0.001) and significant negative association between %TLT and onset of sexual maturity (p<0.001). However, in a subgroup of porpoises with total PCB levels above a proposed threshold of toxicity (>17mg/kg lipid weight) (n=109), the negative association between %TLT (as dependent variable) and summed blubber concentrations of 25 chlorobiphenyl congeners (∑25CBs) remained significant (p<0.01) along with nutritional status (p<0.001) and onset of sexual maturity (p<0.001). These results suggest PCB-induced immuno suppression may be occurring in harbour porpoises in UK waters but only at concentrations that exceed proposed toxicity thresholds for marine mammals. In contrast, development of thymic cysts appears predominantly age-related.

Emerging infectious disease leads to rapid population declines of common British birds

Emerging infectious diseases are increasingly cited as threats to wildlife, livestock and humans alike. They can threaten geographically isolated or critically endangered wildlife populations; however, relatively few studies have clearly demonstrated the extent to which emerging diseases can impact populations of common wildlife species. Here, we report the impact of an emerging protozoal disease on British populations of greenfinch Carduelis chloris and chaffinch Fringilla coelebs, two of the most common birds in Britain. Morphological and molecular analyses showed this to be due to Trichomonas gallinae. Trichomonosis emerged as a novel fatal disease of finches in Britain in 2005 and rapidly became epidemic within greenfinch, and to a lesser extent chaffinch, populations in 2006. By 2007, breeding populations of greenfinches and chaffinches in the geographic region of highest disease incidence had decreased by 35% and 21% respectively, representing mortality in excess of half a million birds. In contrast, declines were less pronounced or absent in these species in regions where the disease was found in intermediate or low incidence. Also, populations of dunnock Prunella modularis, which similarly feeds in gardens, but in which T. gallinae was rarely recorded, did not decline. This is the first trichomonosis epidemic reported in the scientific literature to negatively impact populations of free-ranging non-columbiform species, and such levels of mortality and decline due to an emerging infectious disease are unprecedented in British wild bird populations. This disease emergence event demonstrates the potential for a protozoan parasite to jump avian host taxonomic groups with dramatic effect over a short time period.

The emerging amphibian pathogen Batrachochytrium dendrobatidis globally infects introduced populations of the North American bullfrog, Rana catesbeiana

Batrachochytrium dendrobatidis is the chytridiomycete fungus which has been implicated in global amphibian declines and numerous species extinctions. Here, we show that introduced North American bullfrogs (Rana catesbeiana) consistently carry this emerging pathogenic fungus. We detected infections by this fungus on introduced bullfrogs from seven of eight countries using both PCR and microscopic techniques. Only native bullfrogs from eastern Canada and introduced bullfrogs from Japan showed no sign of infection. The bullfrog is the most commonly farmed amphibian, and escapes and subsequent establishment of feral populations regularly occur. These factors taken together with our study suggest that the global threat of B. dendrobatidis disease transmission posed by bullfrogs is significant.

The role of protein kinase C in lipopolysaccharide-induced myocardial depression in guinea pigs

The effect of lipopolysaccharide (LPS) on cardiac protein kinase C (PKC) activation and cardiac depression was evaluated. Guinea pigs (n = 44) received intraperitoneal injections of saline or Escherichia coli LPS (2 mg/kg). Left atria were harvested 16 h later and suspended in oxygenated low calcium (1 mM) (n = 24) or high calcium (5 mM) (n = 20) 30 degrees C Krebs-Henseleit buffer. Atria were treated with H-7 (n = 23), a PKC inhibitor, or vehicle (n = 21). Contractile responses to changes in preload and stimulating frequency, in the resting and potentiated states, and to escalating doses of phenylephrine were measured. PKC activation in ventricular muscle was also determined. LPS activated ventricular PKC (p < .05) but treatment with H-7 failed to reverse LPS-induced atrial dysfunction in the low calcium buffer. Contractile function in the potentiated state indicated that LPS appears to interfere with calcium release from the sarcoplasmic reticulum (SR). The contractile response to phenylephrine was markedly attenuated in atria harvested from endotoxic animals. These data indicate that LPS-induced cardiac depression is mediated, in part, by alterations in SR calcium release. LPS activates cardiac PKC but a causal relationship among LPS, PKC, and cardiac dysfunction remains to be established.

Tumor necrosis factor-alpha causes myocardial depression in guinea pigs

BACKGROUND AND METHODS

Tumor necrosis factor-alpha (TNF-alpha) is an important mediator of metabolic and cardiovascular derangements in sepsis and endotoxicosis. We tested the hypothesis that TNF-alpha causes myocardial depression and alters the cardiac responsiveness to administered norepinephrine. Albino Hartley guinea pigs (n = 32) of either sex were injected iv with saline (1.5 mL) or recombinant human TNF-alpha (1 mg/kg). At 6, 24, or 72 hrs after injection, atria were harvested, split, connected to force displacement x transducer-amplifier-recorder systems and maintained in vitro in oxygenated 37.5 degrees C Krebs-Henseleit buffer.

RESULTS

Maximal left atrial force of contraction and maximal left atrial velocity of contraction were decreased in the TNF-alpha treated animals compared with controls (p less than .05), irrespective of time after TNF-alpha injection. There were no differences between groups for left atrial maximal velocity of relaxation and right atrial rate. The norepinephrine concentration that elicited a 50% maximal left atrial contractile response (ED50) was higher in TNF-alpha treated animals compared with controls (p less than .05). Maximal left atrial force of contraction, maximal right atrial rate, and right atrial ED50 were similar in the two groups.

CONCLUSIONS

These results indicate that TNF-alpha injected in vivo causes in vitro myocardial depression and alters cardiac responsiveness to norepinephrine.

Intraoperative complications in patients receiving amiodarone: characteristics and risk factors

This article reviews amiodarone's adverse cardiovascular properties, concentrating on those in surgical patients, and evaluates several potential risk factors. Amiodarone has negative inotropic and chronotropic properties as well as peripheral vasodilating properties that may manifest as bradycardia, reduced cardiac output, and hypotension. These reactions are clinically important during surgery, because of resistance to pharmacologic resuscitation and an increased mortality rate. Potential risk factors include ventricular dysfunction, rapid infusion rate, hypocalcemia, cardiopulmonary bypass, general anesthesia, concurrent negative inotropic or chronotropic drugs, and an elevated serum amiodarone or desethylamiodarone concentration. The following measures may decrease the risk of intraoperative adverse reactions in amiodarone-treated patients. The serum calcium concentration should be at the physiologic level and the serum amiodarone and digoxin concentrations should be in the therapeutic range. Negative inotropic and chronotropic agents should be discontinued when possible. A temporary cardiac pacemaker may prevent intraoperative hypotension due to bradycardia. Amiodarone may be discontinued before surgery to minimize the risk of intraoperative complications, but this decision should balance the potential for amiodarone-associated intraoperative complications against the risk of arrhythmia recurrence and the delay of surgery.

A model to decrease hepatic blood flow and cardiac output with pressure breathing

This randomized, controlled, crossover study evaluated the effect of continuous positive airway pressure (CPAP) breathing on hepatic blood flow (HBF) and cardiac output in 10 healthy male subjects. A CPAP mask was placed on the face and the subject breathed at either CPAP 12.5 cm H2O or ambient airway pressure. The estimated HBF was calculated as the ratio of indocyanine green plasma clearance to one minus the hematocrit. Cardiac output was measured with Doppler ultrasound. CPAP caused HBF to decrease in 8 of 10 subjects (14.1% +/- 15.3%, mean +/- SD, p = 0.033) and cardiac index (CI) to decrease in all subjects (14.1% +/- 5.7%, p = 0.0001). Stroke volume and respiratory rate were significantly decreased; heart rate was unchanged. These results indicate that CPAP at 12.5 cm H2O causes a small, but significant decrease in both HBF and CI.

Physiologic implications of mechanical ventilation on pharmacokinetics

Numerous factors present in the critically ill patient decrease drug clearance. The contribution of one factor, mechanical ventilation, to this decrease is largely unknown and unquantified. This article attempts to review the physiologic effects of mechanical ventilation and to propose theoretical changes in the pharmacokinetics of concomitantly administered drugs. Mechanical ventilation with or without positive end-expiratory pressure is a well-documented cause of decreases in cardiac output, hepatic and renal blood flow, glomerular filtration rate, and urine flow. The mean airway pressure delivered, the pathophysiologic state of the patient, and coexisting therapeutic interventions affect the degree of hemodynamic alteration. Theoretically, these hemodynamic changes can decrease the clearance of several drugs frequently administered to critically ill patients. Decreased hepatic blood flow decreases the clearance of nonrestrictively cleared drugs. The pharmacokinetics of drugs predominantly renally cleared, by either glomerular filtration or tubular secretion, are affected by a decrease in renal blood flow or glomerular filtration rate. Also, the clearance of agents for which tubular reabsorption is important may decrease because the reduction in urine flow resulting from mechanical ventilation allows increased time for drug reabsorption. Interventions that minimize the decrease in cardiac output and organ blood flow and, theoretically, the risk of the adverse drug reactions from decreased drug clearance include expansion of intravascular volume, administering positive inotropic agents, and decreasing mean airway pressure. Monitoring serum concentration of critical and toxic agents suspected to have altered clearance in patients receiving mechanical ventilation is recommended. We hope that our article will stimulate future research in this area to give clinicians guidelines for drug dosing in patients receiving mechanical ventilation.

Female homosexuality and body build

A recent report utilizing self-reported and small-small-size data suggests that group differences in body build between heterosexual and homosexual women are likely to be minor. The data presented in this paper do not support this contention. Interviews were conducted with 241 nonpatient, exclusively homosexual women to determine their socioeconomic status, their psychosexual identification, and their overt sexual behavior patterns. The entire sample was then divided into seven psychosexual/behavioral categories derived from the interview data. Anthropometric data were collected for five subsamples and included (1) height measurements, (2) biacromial and bi-iliac measurements, (3) androgyny scores, (4) arm and leg girth measurements, (5) bicondylar diameters of the femur and humerus, (6) triceps, subscapular, and suprailiac skinfolds, and (7) somatotype profiles. These data indicate that the homosexual women have narrower hips, increased arm and leg girths, less subcutaneous fat, and more muscle than heterosexual women.