Reduced lactate dehydrogenase activity in the heart and suppressed sex hormone levels are associated with female-biased mortality during thermal stress in Pacific salmon.

Female-biased mortality has been repeatedly reported in Pacific salmon during their upriver migration in both field studies and laboratory holding experiments, especially in the presence of multiple environmental stressors, including thermal stress. Here, we used coho salmon (Oncorhynchus kisutch) to test whether females exposed to elevated water temperatures (18°C) (i) suppress circulating sex hormones (testosterone, 11-ketotestosterone and estradiol), owing to elevated cortisol levels, (ii) have higher activities of enzymes supporting anaerobic metabolism (e.g. lactate dehydrogenase, LDH), (iii) have lower activities of enzymes driving oxidative metabolism (e.g. citrate synthase, CS) in skeletal and cardiac muscle, and (iv) have more oxidative stress damage and reduced capacity for antioxidant defense [lower catalase (CAT) activity]. We found no evidence that a higher susceptibility to oxidative stress contributes to female-biased mortality at warm temperatures. We did, however, find that females had significantly lower cardiac LDH and that 18°C significantly reduced plasma levels of testosterone and estradiol, especially in females. We also found that relative gonad size was significantly lower in the 18°C treatment regardless of sex, whereas relative liver size was significantly lower in females held at 18°C. Further, relative spleen size was significantly elevated in the 18°C treatments across both sexes, with larger warm-induced increases in females. Our results suggest that males may better tolerate bouts of cardiac hypoxia at high temperature, and that thermal stress may also disrupt testosterone- and estradiol-mediated protein catabolism, and the immune response (larger spleens), in migratory female salmon.

Naphthenic acid fraction compounds reduce the reproductive success of wood frogs (Rana sylvatica) by affecting offspring viability.

Understanding the toxicity of organic compounds in oil sands process-affected water (OSPW) is necessary to inform the development of environmental guidelines related to wastewater management in Canada's oil sands region. In the present study, we investigated the effects of naphthenic acid fraction compounds (NAFCs), one of the most toxic components of OSPW, on mating behaviour, fertility, and offspring viability in the wood frog (Rana sylvatica). Wild adult wood frogs were exposed separately from the opposite sex to 0, 5, or 10 mg/L of OSPW-derived NAFCs for 24 h and then combined in outdoor lake water mesocosms containing the same NAFC concentrations (n = 2 males and 1 female per mesocosm, n = 3 mesocosms per treatment). Mating events were recorded for 48 h and egg masses were measured to determine adult fertility. NAFC exposure had no significant effect on mating behaviour (probability of amplexus and oviposition, amplexus and oviposition latency, total duration of amplexus and number of amplectic events) or fertility (fertilization success and clutch size). Tadpoles (50 individuals per mesocosm at hatching, and 15 individuals per mesocosm from 42 d post-hatch) were reared in the same mesocosms under chronic NAFC exposure until metamorphic climax (61-85 d after hatching). Offspring exposed to 10 mg/L NAFCs during development were less likely to survive and complete metamorphosis, grew at a reduced rate, and displayed more frequent morphological abnormalities. These abnormalities included limb anomalies at metamorphosis, described for the first time after NAFC exposure. The results of this study suggest that NAFCs reduce wood frog reproductive success through declines in offspring viability and therefore raise the concern that exposure to NAFCs during reproduction and development may affect the recruitment of native amphibian populations in the oil sands region.

Corrigendum to: Sex-specific differences in swimming, aerobic metabolism and recovery from exercise in adult coho salmon (Oncorhynchus kisutch) across ecologically relevant temperatures.

[This corrects the article DOI: 10.1093/conphys/coab016.].

Thyroid hormone regulation of thermal acclimation in ectotherms: Physiological mechanisms and ecoevolutionary implications.

The pathways that regulate adaptive thermal plasticity in ectothermic vertebrates have received little attention relative to those in birds and mammals. However, there is increasing evidence that thyroid hormone represents a critical regulator of thermal plasticity in both ectothermic and endothermic vertebrates. In this review, I summarize the evidence for thyroid hormone-mediated thermal compensation responses in ectothermic vertebrates, with specific focus on effects on the whole animal, skeletal muscle, and cardiac muscle. Interestingly, these effects can differ wildly between focal tissues and species. I move on to discuss what the role of thyroid hormone in ectotherm thermal plasticity can reveal about stressor interactions and central vs. peripheral levels of thyroid hormone regulation. Lastly, I focus on the conserved nature of thyroid hormone signaling in animal thermal responses, with specific reference to the ectotherm → endotherm spectrum. I use this framework to highlight research avenues that will further resolve the evolutionary trajectory of thyroid hormone actions across animals. I hope to emphasize what thyroid hormone-mediated cold acclimation in a 3 cm fish can contribute to ongoing debates surrounding the impacts of stressor interactions, the potential costs of plasticity, the evolution of endothermy, and the impacts of global change.

Sex-specific differences in swimming, aerobic metabolism and recovery from exercise in adult coho salmon (Oncorhynchus kisutch) across ecologically relevant temperatures.

Adult female Pacific salmon can have higher migration mortality rates than males, particularly at warm temperatures. However, the mechanisms underlying this phenomenon remain a mystery. Given the importance of swimming energetics on fitness, we measured critical swim speed, swimming metabolism, cost of transport, aerobic scope (absolute and factorial) and exercise recovery in adult female and male coho salmon (Oncorhynchus kisutch) held for 2 days at 3 environmentally relevant temperatures (9°C, 14°C, 18°C) in fresh water. Critical swimming performance (U crit) was equivalent between sexes and maximal at 14°C. Absolute aerobic scope was sex- and temperature-independent, whereas factorial aerobic scope decreased with increasing temperature in both sexes. The full cost of recovery from exhaustive exercise (excess post-exercise oxygen consumption) was higher in males compared to females. Immediately following exhaustive exercise (i.e. 1 h), recovery was impaired at 18°C for both sexes. At an intermediate time scale (i.e. 5 h), recovery in males was compromised at 14°C and 18°C compared to females. Overall, swimming, aerobic metabolism, and recovery energetics do not appear to explain the phenomenon of increased mortality rates in female coho salmon. However, our results suggest that warming temperatures compromise recovery following exhaustive exercise in both male and female salmon, which may delay migration progression and could contribute to en route mortality.

Evolution of the nuclear-encoded cytochrome oxidase subunits in vertebrates.

Vertebrate mitochondrial cytochrome c oxidase (COX) possesses 10 nuclear-encoded subunits. Six subunits have paralogs in mammals, but the origins and distribution of isoforms among vertebrates have not been analyzed. We used Bayesian phylogenetic analysis to interpret the origins of each subunit, inferring the roles of gene and genome duplications. The paralogous ancestries of five genes were identical throughout the major vertebrate taxa: no paralogs of COX6c and COX7c, two paralogs of COX4 and COX6a, and three paralogs of COX7a. Two genes had an extra copy in teleosts (COX5a, COX5b), and three genes had additional copies in mammals (COX6b, COX7b, COX8). Focusing on early vertebrates, we examined structural divergence and explored transcriptional profiles across zebrafish tissues. Quantitative transcript profiles revealed dramatic differences in transcript abundance for different subunits. COX7b and COX4 transcripts were typically present at very low levels, whereas COX5a and COX8 were in vast excess in all tissues. For genes with paralogs, two general patterns emerged. For COX5a and COX8, there was ubiquitous expression of one paralog, with the other paralog in lower abundance in all tissues. COX4 and COX6a shared a distinct expression pattern, with one paralog dominant in brain and gills and the other in muscles. The isoform profiles in combination with phylogenetic analyses show that vertebrate COX isoform patterns are consistent with the hypothesis that early whole genome duplications in basal vertebrates governed the isoform repertoire in modern fish and tetrapods, though more recent lineage-specific gene/genome duplications also play a role in select subunits.

Evolutionary affinity of billfishes (Xiphiidae and Istiophoridae) and flatfishes (Plueronectiformes): Independent and trans-subordinal origins of endothermy in teleost fishes.

Billfishes (Scombroidei) and tunas (Scombridae), both considered part of the suborder Scombroidei, have long been studied by biologists largely because of their remarkable physiological and anatomical muscular adaptations associated with regional endothermy and continuous swimming. These attributes, combined with analyses of other morphological and molecular data, have led to a general perception that tunas and billfishes are close relatives, though this hypothesis has been vigorously debated. Using Bayesian phylogenetic analysis of nine mitochondrial and three nuclear loci (>7000bp), we show that billfishes are only distantly related to tunas, but rather share strong evolutionary affinities with flatfishes (Pleuronectiformes) and jacks (Carangidae). This phylogenetic relationship is striking because of the marked variation in phenotype and niche across these trans-ordinal groups of fishes. Billfishes and flatfishes have each evolved radically divergent morphological and physiological features: elongated bills and extraocular heater organs in billfishes, and cranial asymmetry with complete eye migration during ontogenetic development in flatfishes. Despite this divergence, we identify synapomorphies consistent with the hypothesis of a common billfish/flatfish/jack ancestor.

Comparative biochemistry of cytochrome c oxidase in animals.

Cytochrome c oxidase (COX), the terminal enzyme of the electron transport system, is central to aerobic metabolism of animals. Many aspects of its structure and function are highly conserved, yet, paradoxically, it is also an important model for studying the evolution of the metabolic phenotype. In this review, part of a special issue honouring Peter Hochachka, we consider the biology of COX from the perspective of comparative and evolutionary biochemistry. The approach is to consider what is known about the enzyme in the context of conventional biochemistry, but focus on how evolutionary researchers have used this background to explore the role of the enzyme in biochemical adaptation of animals. In synthesizing the conventional and evolutionary biochemistry, we hope to identify synergies and future research opportunities. COX represents a rare opportunity for researchers to design studies that span the breadth of biology: molecular genetics, protein biochemistry, enzymology, metabolic physiology, organismal performance, evolutionary biology, and phylogeography.

Perioperative blood transfusions and cancer recurrence.

This collective review addresses the issue of transfusion-induced immunosuppression as it relates to patients undergoing cancer surgery. Patients receiving perioperative blood transfusions have a significantly worse prognosis than patients undergoing cancer surgery without a perioperative transfusion. It is thought that this is because transfusions produce a nonspecific immunosuppression by increasing the number and/or activity of suppressor T lymphocytes, decreasing the number of natural killer cells, and inducing anti-idiotypic antibodies. This risk, particularly when considered with the other risks of transfusion such as hepatitis or the acquired immunodeficiency syndrome (AIDS), suggests that criteria for transfusion of these patients should be stringent and related to an unequivocal need for replenishment of RBCs.

Diagnostic methods in lung cancer.

We feel that the guidelines described here reflect the state of the art at the time of writing (April 1982). The role of CT scanning is likely to evolve further and nuclear magnetic resonance (NMR) will probably play a significant role in the future. Experience, expertise, and equipment will vary from one hospital to another and thus rigid rules cannot reasonably be applied for the workup of suspected lung cancer. Ideally the diagnostic approach to an individual patient will be highly tailored, not only in regard to the nature of the pulmonary lesion, but also to his or her overall medical and social situation. We have found that a policy of early consultation between clinician and imaging specialist most readily facilitates effective use of available diagnostic resources.

Thoracic trauma in children.

A 20-year experience at The University of Chicago in dealing with chest injuries in pediatric patients has been reviewed. The clinical presentation, including results of diagnostic measures, and the initial and definitive management of thoracic trauma in children are discussed. The condition of the majority of patients was stable at time of presentation. The most frequent surgical intervention performed was intercostal tube placement. Thoracotomy was infrequently required and laparotomy for associated injuries was more common. Trends in the causes and epidemiology of thoracic trauma in an inner city environment over this 20-year period were noted: Blunt trauma, which is increasing in frequency, most commonly involves the younger age group and is usually related to automobile accidents. Penetrating injuries are generally seen in older patients within the pediatric age groups and are similar to those seen in the adult population.

Clinical staging of patients with non-small cell lung cancer.

This article is the first in a planned series from the Section on Lung Cancer of the ACCP addressing the important and clinically relevant aspects of what is now the most common malignancy in the world, lung cancer. This initial report addresses the problem of staging of lung cancer. Staging, or identifying the anatomic extent of disease according to the AJCC TNM classification scheme, is the first clinical activity in caring for a patient with known or presumed lung cancer because the results determine appropriate types of therapy. This is, therefore, a critically important aspect of the patient's care which forms the foundation for subsequent treatment. In addition, consistent use of this system, based on appropriate clinical and pathologic staging, in stratifying patients in clinical reports is mandatory; otherwise, meaningful comparisons and conclusions are impossible.

Pericardioscopy as adjunct to pericardial window.

A technique for pericardioscopy at the time of subxiphoid pericardial window was evaluated in 17 patients undergoing surgery for clinically suspected malignant pericardial effusion. Best results were obtained using a rigid mediastinoscope for inspection of the posterior and lateral pericardial surfaces. No complications ensued, although many patients experienced cardiac arrythmias which always resolved with removal of the scope. Pericardioscopy revealed cancer transgressing the pericardium near the pulmonary veins in one patient, and this would have been missed without pericardioscopy. Pericardioscopy confirmed palpable metastatic deposits on the inferior pericardial surface in two other patients. In 14 patients, pericardioscopy did not reveal malignancy, although four of these patients had both positive fluid cytologic findings and malignant infiltration of the pericardial biopsy. In one patient a palpable but not visible nodule was proved to be an extrinsic hepatic metastasis. Pericardioscopy is a safe intervention chiefly applicable in patients with central tumors and pericardial effusion in whom subxiphoid pericardial window is not clearly diagnostic at the time of surgery.

Metastatic squamous cell carcinoma of the mediastinum with unknown primary tumor.

Although metastatic carcinoma from an unknown primary tumor is known to occur, the combination of squamous cell carcinoma histologic findings and a mediastinal location is quite unusual. The evaluation of a case of a patient with a posterior mediastinal mass, eventually shown to be metastatic squamous cell carcinoma of the mediastinum with unknown primary tumor, is described herein. Resection of the lymph node mass was performed and was followed by chemoradiation for presumed lung cancer.

Yellow nails, lymphedema and pleural effusion. Treatment of chronic pleural effusion with pleuroperitoneal shunting.

Pleural effusion secondary to lymphedema may be chronic, symptomatic and refractory to treatment, occasionally requiring invasive and painful procedures such as chemical pleurodesis, open pleural abrasion or pleurectomy to achieve control of the effusion and gain symptomatic relief. We report a patient with yellow nail syndrome and chronic pleural effusion successfully treated with pleuroperitoneal shunting.

Reoperation for failed antireflux operations.

UNLABELLED: Experience with gastroesophageal reflux in patients without prior operations has yielded understanding of pathophysiology, surgical techniques, and results. Less is known about patients with failed antireflux operations. This report of 61 patients undergoing repeat antireflux procedures addresses this issues. Not included are patients with gastroesophageal reflux after ulcer operations or with inappropriate antireflux operations for motility disorders. Group A patients (n = 34) had only one previous operation, Group B (n = 19) had two, and Group C (n = 8) had three or more. Group C had significantly (p less than 0.05) more dysphagia and less heartburn than Group A. This observation correlated with findings from manometry, pH testing, and endoscopy, which showed progressively worse esophageal body function and a greater incidence of severe esophagitis and esophageal leak, but less gastroesophageal reflux, in Group C than B and in Group B compared to A. Operative mortality was 4.9%. Repeat antireflux operations in the 58 survivors were as follows: Group A included 25 standard antireflux procedures and seven bowel interpositions, and 75% were transthoracic. Group B included 16 antireflux procedures and one bowel interposition, and 82% were transthoracic. Group C included four antireflux procedures and three interpositions, and all were transthoracic. Clinical results were excellent or good in 85% in Group A, 66% in Group B, and only 42% in Group C (A versus C, p less than 0.05). Surgical complications increased from 27% in Group A to 75% in Group C (p less than 0.05). CONCLUSIONS: Patients with one prior operation and recurrent gastroesophageal reflux are similar to patients with no prior operations. Results of repeat antireflux operations deteriorate with increasing operations because of impaired esophageal function and progressive tissue destruction. Therefore, second reoperations must be definitive and resection and reconstruction with healthy tissue considered. A transthoracic approach is preferable for first reoperations and mandatory after multiple antireflux procedures.

Diagnosis and management of synchronous lung cancers.

The findings in 28 patients with synchronous lung cancers are reviewed. Mediastinoscopy and systemic staging were performed to exclude the possibilities that one pulmonary lesion was metastatic from the other or that both represented systemic metastases from another tumor. Nineteen patients underwent resection of both tumors. Median survival was 25 months for four patients with definite Stage I synchronous cancers (no nodal involvement; different cell types, bronchoscopically separate endobronchial lesions or arising from separate foci of carcinoma in situ) and was 27 months for seven patients with possible synchronous Stage I cancers (no nodal involvement; similar cell types; located in separate lobes). Median survival was 11 months for 16 patients having Stage II or III lung cancer accompanied by a second synchronous lung cancer. In the absence of hilar or mediastinal nodal involvement and systemic metastases, synchronous tumors should be considered separate primaries when located in different lobes, even if they have similar histologic features. Prognosis of synchronous cancers is related to the presence or absence of nodal metastases. Pneumonectomy is the operation of choice for synchronous unilateral tumors. With bilateral tumors, sequential resection starting with the most advanced lesion is appropriate. Preservation of lung tissue without compromising the cancer operation is critical.

Intraoperative lymphatic mapping for non-small cell lung cancer: the sentinel node technique.

BACKGROUND: The purpose of the study was to determine the accuracy and role of the sentinel node technique in patients with non-small cell lung cancer. METHODS: This study was carried out on 36 consecutive patients undergoing lung resection. Peritumoral tissue was infiltrated with isosulfan blue dye and the first lymph node to stain was identified as a sentinel node. Sensitivity and specificity of the sentinel node in predicting the status of other lymph node stations were determined. RESULTS: Seventeen patients had sentinel lymph nodes. In 9 of these 17 cases neither the sentinel node nor any other lymph node contained metastatic carcinoma. In 5 cases the sentinel node was in the mediastinum and documented unexpected N2 disease. In 19 patients no sentinel node was found. Final lymph node statuses were N0 in 13 patients, N1 in 5, and N2 in 1. CONCLUSIONS: The use of isosulfan blue for intraoperative lymphatic mapping is feasible. The specificity in our experience was good; 9 of 9 patients with negative sentinel nodes were found to be N0 on the final pathology report. Unexpected N2 disease was found in 5 patients. The accumulation of further experience will determine the role of the sentinel node technique in patients with non-small cell lung cancer.

The impact of nutritional status on the outcome of lung volume reduction surgery: a prospective study.

OBJECTIVES: To study the incidence and clinical significance of nutritional deficiencies in patients with emphysema undergoing lung volume reduction surgery (LVRS). DESIGN: Prospective observational study. SETTING: University-based teaching hospital. PATIENTS: Fifty-one consecutive patients with end-stage emphysema undergoing video-assisted thoracoscopic surgery for LVRS. INTERVENTIONS: All patients had their body mass index (BMI) and serum nutritional indexes (albumin, transferrin, total protein, cholesterol) measured preoperatively and postoperatively. Various clinical parameters were also compared between two groups. RESULTS: The BMI was normal in 24 patients (47%), and 27 patients (53%) had a below normal BMI. A preoperative analysis of the serum nutritional indexes revealed no clinically significant differences between the two groups, but postoperative levels were significantly lower in the low BMI group. Anthropometric measurements supported the designation of nutritional status by BMI. Clinically, 26% of the patients in the low BMI group required prolonged ventilatory support (> 24 h), compared to only 4% of the patients with a normal BMI. The hospital length of stay (LOS) also differed, averaging 15.9 days in the low BMI group, compared to an average of 11.8 days in the normal BMI group. CONCLUSION: Approximately 50% of patients undergoing LVRS for emphysema have a deficient nutritional status identifiable by BMI, but not by standard nutritional indexes. This impaired nutritional status is associated with increased morbidity following LVRS. We suggest that BMI is an accurate determinant of nutritional status in this patient population, and we speculate that preoperative repletion of nutritional deficiencies may decrease hospital morbidity, hospital LOS, and overall costs in the malnourished population undergoing LVRS.

Guided biopsies of abnormalities on nuclear bone scans. Technique and indications.

A guided biopsy technique has been developed for evaluation of solitary bone abnormalities, identified by gallium 67 or technetium 99 bone scans, in patients with normal or ambiguous x-ray findings. Continuous gamma camera monitoring is used to guide staining of the bone abnormality and overlying tissues with methylene blue. This staining is followed by open biopsy of the marked bone. This technique was utilized in 15 patients, 12 of whom had bronchogenic carcinoma. The most commonly involved bones (13/15) were ribs. None of the patients had an identifiable, gross abnormality at operation, and the marked area was indistinguishable from neighboring tissues. Diagnostic tissue was obtained by each biopsy and there were no complications associated with this technique. The primary applicability of this technique is for both pretreatment and re-treatment staging of bronchogenic carcinoma in patients who have ambiguous nuclear bone scan abnormalities.