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Rising ocean temperature is a major driver of kelp forest decline worldwide and one that threatens to intensify over the coming decades. What is not particularly well understood are the mechanisms that drive loss and how they operate at differing life stages. This study aimed to establish an understanding of the effects of increasing temperature on the early developmental stages of the giant kelp, Macrocystis pyrifera. Sporulation was carried out across 10 temperature treatments from 9.5 to 26.2°C ± 0.2°C at approximately 2°C intervals. Spores were then incubated at these temperatures under a 20.3±1.7 μmol photons m-2 s-1, 16L:8D photoperiod for 5 days. Results indicate that spore release was positively correlated with increasing temperature, whereas an inverse trend was observed between temperature and the growth of germ-tube. The thermal threshold for spore and germling development was determined to be between 21.7°C and 23.8°C. Spore settlement was the most drastically effected developmental phase by increasing temperature. This study highlights the vulnerability of early life stages of M. pyrifera development to rising ocean temperature and has implications for modelling future distribution of this valuable ecosystem engineer in a changing ocean., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2022 Le et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Coralline algae (CA) are globally distributed and fulfil many important roles within coastal ecosystems. In this study, photosynthetically active radiation (PAR) measured for 616 days at 2 and 10 m in a temperate subtidal kelp forest in southern New Zealand provided context to photosynthesis vs. irradiance relationships for, and pigment concentrations of, an articulated coralline alga, Arthrocardia sp. and a crustose coralline species assemblage within the Hapalidiales order. The maximum photosynthetic rate P max of the Arthrocardia sp. (20.38 ± 2.38 µmol O 2 . gDW -1 h -1 ) was significantly higher than the P max of crustose coralline spp. (3.72 ± 0.74 µmol O 2 . gDW -1 h -1 ) at the same 2 m stratum. Pigment concentration of Arthrocardia sp. was significantly higher than that of crustose coralline spp. at the same depth, while pigment concentration of crustose coralline spp. at 2 and 10 m were not significantly affected by depth. The photosynthetic characteristics of these coralline algae represent a shade acclimated organism with low saturation irradiance (all E k  < 100 µmol photons m -2  s -1 ). Despite sevenfold difference in average daily dose between 2 and 10 m there was no significant effect of depth on the photosynthetic performance of crustose coralline algae measured. The lack of evidence for acclimation to low light could be because periods of clear water provide enough light to maintain photosynthesis, lower energetic requirements of species found at depth or constraints on the synthesis of photosynthetic pigments at greater depth., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Light availability is a fundamental factor that controls the productivity and distribution of macroalgae and is highly variable, both spatially and temporally, in subtidal coastal systems. Our comprehension of how macroalgae respond to such variability is a significant knowledge gap that limits our understanding of how light influences the structure and productivity of these environments. Here, we examined the pigment characteristics of individual species, and for the first time the whole community, within one low-light, and one high-light kelp-forest system in southern New Zealand. The aim was to quantify the range of pigmentation seen within the two kelp-forests which differed in irradiance regime. Light availability was 33% and 64% greater at the high-light compared to the low-light site at 2 and 10 m depth, respectively. Results suggested Phaeophyceae species at deeper depths in the low-light site may be living at the edge of their photosynthetic ability and pigment synthesis appeared significantly restricted. Even with greater investment in the pigment fucoxanthin, biomass of Phaeophyceae species was significantly lower in the low-light site. Highly pigmented Rhodophyceae species made a greater proportional contribution to community biomass within the low-light site where they likely possessed a photosynthetic advantage. This work helps explain discrepancies in community structure between the two study sites and explores the complex relationship between irradiance and photoacclimation. The comparison of community pigment concentration holds potential as a tool for assessing the relative degree of photoacclimation occurring between sites and provides a proxy of photosynthetic cost under a specific light regime., (© 2019 Phycological Society of America.)

The role of how light is delivered over time is an area of macroalgal photosynthesis that has been overlooked but may play a significant role in controlling rates of productivity and the structure and persistence of communities. Here we present data that quantify the relative influence of total quantum dose and delivery rate on the photosynthetic productivity of five ecologically important Phaeophyceae species from southern New Zealand. Results suggested that greater net oxygen production occurs when light is delivered at a lower photon flux density (PFD) over a longer period compared to a greater PFD over a shorter period, given the same total dose. This was due to greater efficiency (α) at a lower PFD which, for some species, meant a compensatory effect can occur. This resulted in equal or greater productivity even when the total quantum dose of the lower PFD was significantly reduced. It was also shown that light limitation at Huriawa Peninsula, where macroaglae were sourced, may be restricting the acclimation potential of species at greater depths, and that even at shallow depth periods of significant light limitation are likely to occur. This research is of particular interest as the variability of light delivery to coastal reef systems increases as a result of anthropogenic disturbances, and as the value of in situ community primary productivity estimates is recognised.

Light is the fundamental driver of primary productivity in the marine environment. Reduced light availability has the potential to alter the distribution, community composition, and productivity of key benthic primary producers, potentially reducing habitat and energy provision to coastal food webs. We compared the underwater light environment of macroalgal dominated shallow subtidal rocky reef habitats on a coastline modified by human activities with a coastline of forested catchments. Key metrics describing the availability of photosynthetically active radiation (PAR) were determined over 295 days and were related to macroalgal depth distribution, community composition, and standing biomass patterns, which were recorded seasonally. Light attenuation was more than twice as high in shallow subtidal zones along the modified coast. Macroalgal biomass was 2-5 times greater within forested sites, and even in shallow water (2m) a significant difference in biomass was observed. Long-term light dose provided the best explanation for differences in observed biomass between modified and forested coasts, with light availability over the study period differing by 60 and 90 mol photons m-2 at 2 and 10 metres, respectively. Higher biomass on the forested coast was driven by the presence of larger individuals rather than species diversity or density. This study suggests that commonly used metrics such as species diversity and density are not as sensitive as direct measures of biomass when detecting the effects of light limitation within macroalgal communities.

The repeated compaction of Avicel PH101, dicalcium phosphate dihydrate (DCP) powder, 50:50 DCP/Avicel PH101 and Starch 1500 was studied using an instrumented laboratory tablet press which measures upper punch force, punch displacement and ejection force and operates using a V-shaped compression profile. The measurement of work compaction was demonstrated, and the test materials were ranked in order of compaction behaviour Avicel PH101 > DCP/Avicel PH101 > Starch > DCP. The behaviour of the DCP/Avicel PH101 mixture was distinctly non-linear compared with the pure components. Repeated compaction and precompression had no effect on the tensile fracture strength of Avicel PH101 tablets, although small effects on friability and disintegration time were seen. Repeated compaction and precompression reduced the tensile strength and the increased disintegration time of the DCP tablets, but improved the strength and friability of Starch 1500 tablets. Based on the data reported, routine laboratory measurement of tablet work of compaction may have potential as a critical quality attribute of a powder blend for compression. The instrumented press was suitable for student use with minimal supervisor input.

Mutations of the intrinsic lysosomal membrane protein SCARB2 cause action myoclonus-renal failure syndrome (AMRF syndrome), a rare disease characterized by renal and neurological manifestations. In this study, examination of Cos7 cells transfected with SCARB2 cDNA derived from two patients with AMRF syndrome showed that the resultant protein was truncated and was not incorporated into vesicular structures, as occurred with full-length SCARB2 cDNA. Mutant SCARB2 protein failed to colocalize with lysosomes and was found in the endoplasmic reticulum or the cytosol indicating a loss of function. Cultured skin fibroblast and Epstein-Barr virus-transformed lymphoblastoid B cell lines (LCLs) were created from these two patients. Despite the loss of SCARB2 function, studies with lysosomal-associated membrane protein (LAMP) 1 and LAMP2 demonstrated normal lysosomal numbers in fibroblasts and LCLs. Immunofluorescence microscopy using anti-LAMP1 and anti-LAMP2 antibodies also showed normal lysosomal structures in fibroblasts. There was no change in the morphology of fibroblasts examined by electron microscopy compared with cells from unaffected individuals. By contrast, LCLs from individuals bearing SCARB2 mutations had large intracellular vesicles that resembled autophagosomes and contained heterogeneous cellular debris. Some of the autophagosomes were seen to be extruding cellular contents into the media. Furthermore, LCLs had elevated levels of microtubule-associated protein light chain 3-II, consistent with increased autophagy. These data demonstrate that SCARB2 mutations are associated with an inability to process autophagosomes in B lymphocytes, suggesting a novel function for SCARB2 in immune function.

Background/aims: Renin processing and storage is believed to occur in lysosome-like structures in the afferent arteriole. SCARB2/Limp-2 is a transmembrane lysosomal protein responsible for the intracellular trafficking of β-glucocerebrosidase. This study aimed to confirm the expression of SCARB2/Limp-2 in renin secretory granules, and explore its role in renin processing and secretion., Methods: Co-localisation studies of (pro)renin with lysosomal membrane proteins, SCARB2/Limp-2, LAMP-1 and LAMP-2, were performed in mouse and human kidney sections. Intrarenal expression and secretion of (pro)renin in wild-type (WT) and Limp-2(-/-) mice were compared with and without stimulation., Results: SCARB2/Limp-2, LAMP-1 and LAMP-2 co-localised with (pro)- renin in mouse and human kidney. Plasma renin concentration was increased in Limp-2(-/-) mice when compared to WT littermates. No change in (pro)renin expression, however, was observed in Limp-2(-/-) mouse kidney cortex by immunofluorescence microscopy, Western blotting, quantitative RT-PCR or the ultrastructural appearance of renin secretory granules. Acute stimulation of renin release by isoprenaline or hydralazine was similar in WT and Limp-2(-/-) mice. Following chronic salt restriction, however, immunofluorescence microscopy showed less (pro)renin expressed in Limp-2(-/-) compared with WT mouse kidneys, and there was significantly less prorenin but not renin by Western blotting in Limp-2(-/-) mouse kidney cortex, despite no difference in circulating renin levels., Conclusion: Renin secretory granules possess integral lysosomal proteins, confirming that they are indeed modified lysosomes. Limp-2 deficiency leads to a minor increase in circulating renin. Limp-2, however, is not required for acute or chronic stimulation of renin release., (2013 S. Karger AG, Basel)

Deficiency of the intrinsic lysosomal protein human scavenger receptor class B, member 2 (SCARB2; Limp-2 in mice) causes collapsing focal and segmental glomerular sclerosis (FSGS) and myoclonic epilepsy in humans, but patients with no apparent kidney damage have recently been described. We now demonstrate that these patients can develop tubular proteinuria. To determine the mechanism, mice deficient in Limp-2, the murine homolog of SCARB2, were studied. Most low-molecular-weight proteins filtered by the glomerulus are removed in the proximal convoluted tubule (PCT) by megalin/cubilin-dependent receptor-mediated endocytosis. Expression of megalin and cubilin was unchanged in Limp-2(-/-) mice, however, and the initial uptake of injected Alexa Fluor 555-conjugated bovine serum albumin (Alexa-BSA) was similar to wild-type mice, indicating that megalin/cubilin-dependent, receptor-mediated endocytosis was unaffected. There was a defect in proteolysis of reabsorbed proteins in the Limp-2(-/-) mice, demonstrated by the persistence of Alexa-BSA in the PCT compared with controls. This was associated with the failure of the lysosomal protease cathepsin B to colocalize with Alexa-BSA and endogenous retinol-binding protein in kidneys from Limp-2(-/-) mice. The data suggest that tubular proteinuria in Limp-2(-/-) mice is due to failure of endosomes containing reabsorbed proteins to fuse with lysosomes in the proximal tubule of the kidney. Failure of proteolysis is a novel mechanism for tubular proteinuria.

Objective: The purpose of this study was to examine the effect of peri-operative red blood cell (RBC) transfusion on 30-day and 1-year mortality following coronary artery bypass grafting (CABG)., Methods: We retrospectively analysed 3024 consecutive patients who underwent isolated CABG between January 1999 and December 2001. Patient records were linked to the National Strategic Tracing Service, which records all mortality in the UK. Thirty-day and 1-year mortality were derived from Kaplan-Meier curves. Confounding variables were controlled for by constructing a propensity score for the probability of receiving a transfusion from core patient characteristics including the lowest recorded laboratory haemoglobin (LL Hb) from a clinical chemistry database (C statistic 0.81). The propensity score and the comparison variable (transfusion versus no transfusion) were included in a Cox proportional hazards analysis, allowing calculation of adjusted hazard ratios (HR) and Kaplan-Meier survival curves., Results: Nine hundred and forty (31.1%) patients received RBC transfusion during or within 72h of surgery. Predictors of the need for transfusion were LL Hb and lower body mass index, use of cardiopulmonary bypass, female sex, number of grafts, renal dysfunction, increased age, extent of disease, and prior CABG; these factors were all included in the propensity score. After 1-year of follow-up, 122 (4.03%) deaths occurred. The crude HR for 1-year mortality in patients transfused was 3.0 (P<0.001). After adjusting for the propensity score, re-operation for bleeding, peri-operative blood loss and post-operative complications, the adjusted 30-day mortality was 1.9% in transfused patients compared to 1.1% in patients not transfused (P<0.05). The adjusted HR for 1-year mortality in patients transfused was 1.88 (P<0.01)., Conclusions: Peri-operative RBC transfusion after CABG is associated with an increased risk of mortality during a 1-year follow-up period, with a large proportion of deaths occurring within 30-days.

Background: We aimed to identify risk factors for reexploration for bleeding after surgical revascularization in our practice. We also looked at the impact of resternotomy and the effect of time delay on mortality and other in-hospital outcomes., Methods: In all, 2,898 consecutive patients undergoing coronary artery bypass grafting between April 1999 and March 2002 were retrospectively analyzed from our cardiac surgery registry. Multivariate logistic regression analysis was used to identify risk factors for reexploration for bleeding. To assess the effect of preoperative aspirin and heparin, reexploration patients were propensity matched with unique patients not requiring reexploration. We carried out a casenote review to ascertain the timing and causes for bleeding in patients undergoing resternotomy., Results: Eighty-nine patients (3.1%) underwent reexploration for bleeding. Multivariate analysis revealed smaller body mass index (p = 0.003), nonelective surgery (p = 0.022), 5 or more distal anastomoses (p = 0.035), and increased age (p = 0.041) to have increased risks. Propensity-matched analysis showed that preoperative use of aspirin (p = 0.004) and heparin (p = 0.001) were associated with increased risk in the on-pump coronary surgery group only. Patients requiring resternotomy had a significantly greater need for inotropic agents (p < 0.001), and longer intensive care unit stay (p < 0.001) and postoperative stay (p < 0.001) than their propensity-matched controls. However, there was no significant difference in the mortality rate. Adverse outcomes were significantly higher when patients waited more than 12 hours after return to the intensive care unit for resternotomy., Conclusions: Risk factors for reexploration for bleeding after coronary artery bypass grafting include older age, smaller body mass index, nonelective cases, and 5 or more distal anastomoses. Preoperative aspirin and heparin were risk factors for the on-pump coronary artery surgery group. Patients needing reexploration are at higher risk of complications if the time to reexploration is prolonged. Policies that promote early return to the operating theater for reexploration should be encouraged.

Background and Objectives: The purpose of this work was to describe the methodology used to build a transfusion database that allows continuous audit of transfusion practices in coronary artery bypass surgery., Materials and Methods: The transfusion database requires electronic data available from two sources: the hospital's patient administration system; and the local blood transfusion service., Results: We demonstrated a reduction in the percentage of patients receiving red blood cell transfusion: from 47.4% in 1997/1998 to 31.6% in 2001/2002 (P<0.001). Reductions have also been shown in the percentage of patients receiving fresh-frozen plasma and platelet units., Conclusions: The data sourcing the transfusion database should be available to all hospitals through their patient administration systems and local blood transfusion service. Its use can help to reduce transfusion rates significantly.

Between October 1991 and March 1994, 108 consecutive patients with moderate to severe left ventricular dysfunction underwent non-emergency isolated coronary artery surgery under the care of one surgeon (A.R.). They were prospectively randomised to receiving either intermittent cold (Group 1-50 patients) or continuous warm (Group 2-58 patients) blood cardioplegia for myocardial protection. There were no significant differences in clinical outcome between the two groups, as judged by operative mortality, rates of perioperative myocardial infarction, the serum CKMB isoenzyme level at 2 and 18 h after operation, need for circulatory support, postoperative neurological deficit, or duration of hospital stay. Group 2 patients required significantly more potassium (68 vs 29 mmol, P < 0.001) to maintain diastolic arrest and also had higher serum potassium levels after removal of the cross-clamp (P < 0.001). However, sinus rhythm returned spontaneously with greater frequency (91.2% vs 45.8%, P < 0.001) in Group 2 patients. In conclusion this report suggests that retrograde continuous warm blood cardioplegia provides comparable myocardial protection to that achieved with retrograde intermittent cold blood cardioplegia in patients with moderate to severe left ventricular dysfunction undergoing isolated coronary artery surgery.

We studied three groups of patients without previous renal impairment, undergoing elective coronary artery bypass surgery. Group H (n = 7) underwent open heart surgery using moderate hypothermia (28 degrees C); Groups N and M (n = 8, each) were managed at normothermia. The extracorporeal circuit was primed with Hartmann's solution 2.5 L with the addition of mannitol 0.5 g/kg in Group M. Serum concentrations of sodium and creatinine, and the urinary concentrations of microalbumin and N-acetyl-beta-D-glucosaminidase (NAG) were measured in each patient at six different time intervals: T0, 6 h prior to surgery; T1, between sternotomy and 45 min into cardiopulmonary bypass (CPB); T2, in the interval from 45 min into, to prior to weaning off CPB; T3, from coming off CPB to skin closure; T4, in the first 6 h in the intensive care unit; and T5, at 6 days postoperatively. Creatinine clearance (CCR) and fractional sodium excretion (FENA) were calculated at each time point. Urine output during CPB at Interval T2 was significantly higher in Group H compared to Group N (P = 0.03) but not Group M. We found no significant differences in CCR, FENA, microalbuminuria, and urinary NAG among the three groups at any time. However, there were overall significant changes in measured variables over time compared to baseline. We conclude that CPB is associated with a significant alteration in renal function as shown by increased FENA, microalbuminuria, and urinary NAG. The use of hypothermic or normothermic CPB and the use of prophylactic mannitol did not produce any significant modification of these changes.

Between October 1991 and March 1993, 281 consecutive patients underwent non-emergency isolated coronary artery surgery under the care of one surgeon (A.R.). They were prospectively randomised to receive either intermittent cold (Group I-144 patients) or continuous warm (Group II-137 patients) blood cardioplegia for myocardial protection. There were no significant differences in clinical outcome between the two groups, as judged by operative mortality, rates of peri-operative myocardial infarction, blood loss, need for circulatory support, post-operative neurological deficit, or duration of intensive care or hospital stay. However, sinus rhythm returned spontaneously with greater frequency (91.2% vs 45.8%, P < 0.001) in Group II patients. There was greater transmyocardial oxidative stress in Group I patients, as evidenced by a significant rise in oxidised glutathione in coronary sinus blood on myocardial reperfusion. Also, the serum CKMb isoenzyme level 2 h post-operatively was significantly raised in Group I patients, although this difference had disappeared by the day after surgery. In conclusion this preliminary report suggests that continuous warm blood cardioplegia provides comparable myocardial protection to that achieved with standard hypothermic techniques in patients undergoing coronary artery surgery.

Mitral valve surgery may be complicated by a post-operative low output state requiring inotropic support, and a wide variety of factors may influence the choice of agents used to treat this condition. The authors have examined and compared the haemodynamic effects of the highly specific phosphodiesterase inhibitor enoximone, and the adrenergic agents dobutamine and dopamine in patients undergoing mitral valve surgery. Enoximone, 0.5 mg kg-1 bolus, followed by a continuous infusion of 5 micrograms kg-1 min-1, was compared against dobutamine, 7 micrograms kg-1 min-1, and dopamine, 5 micrograms kg-1 min-1, with the protocol allowing for an increase in the infusion rate by a factor of two if clinical and haemodynamic measurements indicated. All 25 patients receiving enoximone were successfully weaned from cardiopulmonary bypass at the first attempt, with significant increases in cardiac index and stroke index, combined with little or no change in heart rate or pulmonary artery pressures and a highly significant reduction in systemic vascular resistance, and a reduction in mean arterial pressure. Three of the 25 patients receiving dobutamine were withdrawn from the study because of inadequate haemodynamic response, while the remaining 22 patients demonstrated significant increases in heart rate, cardiac index and stroke index, with a reduction in systemic vascular resistance. Nine of the 25 patients receiving dopamine failed to respond adequately, while the remaining 16 demonstrated an increase in heart rate and cardiac index but with little change in stroke index and a modest reduction in systemic vascular resistance. Enoximone has been shown to be a highly effective first-line inotrope in patients following mitral valve surgery with significant advantages over dobutamine and dopamine.

A topical anesthetic emulsion consisting of a mixture of lidocaine and prilocaine (EMLA) was used in an attempt to reduce the pain associated with radial artery cannulation. Three groups were compared: (1) EMLA applied at least 90 minutes prior to cannulation (EMLA 90); (2) EMLA applied 60 minutes prior to cannulation (EMLA 60); and (3) lidocaine 2% infiltration performed immediately prior to the procedure (infiltration). Pain was registered using visual analog and verbal ranking scales by both the patient and an independent observer. The EMLA 90 group experienced significantly less pain (P < .001) than either the EMLA 60 or lidocaine infiltration groups. There was no statistically significant difference in pain scores between the EMLA 60 and infiltration groups. Local side-effects of EMLA were negligible.

The anaesthetic management of a patient suffering from carcinoid syndrome and myasthenia gravis is described including the successful treatment of a carcinoid attack with intravenous aprotonin. The differences between myasthenia gravis and the myasthenic (Eaton-Lambert) syndrome are considered and the rationale for the choice of vecuronium as the muscle relaxant is discussed.