Protein-chromophore interactions in alpha-crustacyanin, the major blue carotenoprotein from the carapace of the lobster, Homarus gammarus. A study by 13C magic angle spinning NMR

MAS (magic angle spinning) 13C NMR has been used to study protein-chromophore interactions in alpha-crustacyanin, the blue astaxanthin-binding carotenoprotein of the lobster, Homarus gammarus, reconstituted with astaxanthins labelled with 13C at the 14,14' or 15,15' positions. Two signals are seen for alpha-crustacyanin containing [14,14'-13C2]astaxanthin, shifted 6.9 and 4.0 ppm downfield from the 134.1 ppm signal of uncomplexed astaxanthin in the solid state. With alpha-crustacyanin containing [15,15'-13C2]astaxanthin, one essentially unshifted broad signal is seen. Hence binding to the protein causes a decrease in electronic charge density, providing the first experimental evidence that a charge redistribution mechanism contributes to the bathochromic shift of the astaxanthin in alpha-crustacyanin, in agreement with inferences based on resonance Raman data [Salares, et al. (1979) Biochim. Biophys. Acta 576, 176-191]. The splitting of the 14 and 14' signals provides evidence for asymmetric binding of each astaxanthin molecule by the protein.

Use of transcutaneous electrical nerve stimulation in the control of postoperative chest pain after cardiac surgery

The effect of continuous transcutaneous electrical nerve stimulation (TENS) on postoperative pain following median sternotomy was evaluated in 89 patients with severe chest pain who underwent cardiac surgery in a prospective, randomized, blinded trial. Pain was assessed by visual analog pain scores before and during treatment in each group. In the active TENS group, 79% of the patients were completely free of chest pain during rest at the end of 180 minutes (P less than 0.001). Among the remaining patients with TENS, 16% had slight pain not needing narcotic analgesics and 5% still had chest pain requiring narcotics. In the control group in which inactive TENS was used, the intensity of pain was reduced in 44% of the patients at the end of 90 minutes (P less than 0.001). However, this early placebo effect was noted to diminish with time and at the end of 180 minutes, 80% of the patients complained of severe chest pain and needed narcotics. These data suggest that TENS can be effective in controlling postoperative chest pain due to median sternotomy after cardiac surgery and its continuous application in the early postoperative period can reduce the need for narcotics.

Factors affecting parenting stress among biologically vulnerable toddlers

Parenting a child with, or at risk for, a developmental delay or disability can be stressful. Abidin's parenting stress model was used as a framework to examine how several maternal, child, and family factors predict parent stress outcomes. Stepwise regression models revealed that maternal and child factors were significant contributors to parenting stress. However, family factors (income and family functioning) were not retained. Parenting stress was lower when child (cognitive and adaptive ability) and maternal (depression and child care competence) characteristics were more positive. Child cognitive ability was a strong contributor to total parenting stress and two parenting stress subscales. Findings suggest that these parents need stress lowering interventions such as supportive child care, respite relief, and a child behaviour-focused program.

NMR solution structure of a cytoplasmic surface loop of the human red cell anion transporter, band 3

The membrane domain of the human red cell anion transport protein, band 3, is too large to be studied by solution nuclear magnetic resonance spectroscopy (NMR), and its amphiphilic nature requires the use of detergents for solubilization. An alternative approach is to divide the protein into smaller (trans-membrane or surface loop) domains for NMR study. We report the structure of a 46-residue synthetic peptide that corresponds to the cytoplasmic surface loop connecting the putative 12th and 13th trans-membrane spans (residues 796-841) in the 14 span model of band 3. This peptide was shown by circular dichroism (CD) to be 38% helical in 30% trifluoroacetic acid. Two regions of helix (one close to the N-terminus of the peptide and one close to the C-terminus of the peptide) were identified by NMR. Long-range nuclear Overhauser effect (NOE) cross-peaks showed the two helices to be in near proximity. The helices were separated by a proline-rich loop that exhibited local order but was mobile with respect to the rest of the peptide. We discuss how the NMR structure of this loop fits the current models of band 3 structure and topology and the results of recent mutagenesis experiments. A cyclic version of this peptide was synthesized and studied by CD, but NMR studies were not possible due to the low solubility of this peptide.

Advanced practice nursing in Canada: has the time really come?

Nurse practitioners in Canada have experienced many of the problems facing those in the UK. In this paper, first presented at this year's meeting of the Commonwealth Nurses' Federation, the authors explain the events.

Phenylalanine hydroxylation in isolated rat kidney tubules

1. Phenylalanine hydroxylation has been demonstrated to occur in isolated rat kidney tubules under physiological conditions. 2. The hydroxylation flux response is hyperbolic with apparent Km and Vmax values of ca 85 microM phenylalanine and 49 nmol tyrosine formed/mg dry wt per hr respectively. 3. Hydroxylation in kidney tubules is substantially less sensitive to effectors of cyclic AMP turnover and Ca2+ mobilization than phenylalanine hydroxylation in isolated liver cells.

Fracture liaison services in Ireland-how do we compare to international standards?

In this first na tional survey of public hospitals in The Republic of Ireland, we found fracture liaison services (FLS) to be heterogeneous, limited in many cases and poorly supported. A national strategy is urgently needed to support the implementation and operation of an FLS, and thus help reduce the burden of fragility fractures for patients and the healthcare system.

INTRODUCTION

Fragility/low-trauma fractures are a global concern, whose incidence is rising as the population ages. Many are preventable, and people with a prior fragility fracture are at particularly high risk of further fractures. This patient group is the target of the International Osteoporosis Foundation (IOF) Capture the Fracture campaign, advocating global adoption of fracture liaison services (FLS), with the aim of preventing secondary fragility fractures. We wished to determine the current availability and standards of an FLS in Ireland, ahead of the launch of a National FLS database.

METHODS

We devised a questionnaire encompassing the thirteen IOF standards for an FLS and asked all 16 public hospitals with an orthopaedic trauma unit in Ireland, to complete for the calendar year 2019 in patients aged ≥ 50 years.

RESULTS

All sites returned the questionnaire, i.e. 100% response rate. Nine hospitals stated that they have an FLS, additionally one non-trauma hospital running a FLS responded, and were included. These 10 FLS had identified and managed 3444 non-hip fractures in the year 2019. This figure represents 19% of the expected non-hip fragility fracture numbers occurring annually in Ireland. Implementation of the IOF standards was very variable. All sites reported being inadequately resourced to provide a high-quality service necessary to be effective.

CONCLUSION

The existence and functioning of FLS in Ireland are heterogeneous and suboptimal. A national policy to support the implementation of this programme in line with international standards of patient care is urgently needed.

Porcine liver esterase-catalyzed enantioselective hydrolysis of a prochiral diester into its optically pure (S)-ester acid, a precursor to a growth hormone secretagogue

A limited screen of several commercially-available and internally-produced lipases and esterases identified porcine liver esterase as a suitable biocatalyst for the enantioselective hydrolysis of a diester into its (S)-ester acid with high optical purity (99%). This (S)-ester acid is a precursor to an experimental growth hormone secretagogue. After identifying xanthan gum as the best emulsifier and optimizing the reaction conditions, hydrolysis rates of 1 g/l.h and final (S)-ester acid (ee > 99%) titers of about 8.5 g/l were routinely achieved. This process supported the production of preparative amounts of optically pure (S)-ester (ee > 99%) with a high reaction yield of 82%. Upon purification, the (S)-ester was successfully used in the subsequent synthetic steps to yield the growth hormone secretagogue.

Kynurenine Pathway Dysregulation and Pain Perception in Acute Pancreatitis: Has the Connection Unraveled?

AIM

Tryptophan (TRP), an essential amino acid, undergoes catabolism through various pathways. Notably, the kynurenine pathway (KP), constituting one of these pathways, exhibits a unidirectional impact on immune response and energy metabolism. Nonetheless, its influence on pain sensation is characterized by biphasic dynamics. This study aims to scrutinize the influence of the KP pathway on pain sensation, particularly within the context of pancreatic inflammation.

METHODS

Our prospective case-control study involved individuals diagnosed with acute pancreatitis and a control group matched for gender and age. The patient cohort was subsequently subdivided into severe and non-severe subgroups. To assess metabolites within KP, two blood samples were collected from the patient cohort, one at the time of diagnosis and another during the recovery phase. Furthermore, for pain quantification, daily pain scores utilizing the Visual Analog Scale (VAS) were extracted from the patients' medical records.

RESULTS

The study incorporated 30 patients along with an equivalent number of controls. A noticeable distinction was evident between the patient and control groups, characterized by an increase in kynurenine levels and a decrease in the tryptophan/kynurenine ratio. Throughout the process of disease recovery, a uniform decrease was observed in all KP metabolites, excluding 3-Hydroxykynurenine. Elevated levels of Kynurenic acid (KYNA) were correlated with increased pain scores. Critically, no apparent distinctions in KP metabolites were discerned concerning pain severity in patients with comorbidities characterized by neural involvement.

CONCLUSION

Based on our results, the kynurenine pathway (KP) is activated in instances of acute pancreatitis. Elevated levels of KYNA were found to be associated with heightened pain scores. The operative stages within the KP responsible for pain modulation are impaired in cases characterized by neuropathy-induced pain sensation.

The Patient's Second Hip Fracture - One in Ten

Introduction The number of fragility hip fractures (>60 years) are estimated to triple/quadruple by 2050. It is estimated that the prevalence of patient's contralateral hip fractures (HF2s) will increase also. Methods Single hospital, Retrospective review, 2013-2017, Radiograph review, n = 822. Results Management of patient's 2nd hip fractures accounted for 10.5% of all hip fracture surgeries. ~50% occurred within 3 years of the 1st hip fracture. There was no statistically significant difference in discharge destination, length-of-stay or mortality between the HF1 and HF2 cohorts. Discussion Patients with HF2s comprised a significant and stable proportion of all hip fractures treated. We advocate for the provision of a Fracture Liaison Service in each of the 16 hip fracture operating hospitals in Ireland to optimise the secondary prevention of hip fractures.

Does obesity change the effect of aromatase inhibitors (AIs) on estradiol, leptin, insulin, and IGF-1 serum levels in breast cancer patients?

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Background: The complexity of the relationship between obesity and breast cancer reflects important contributions of obesity-related factors in the adjuvant therapy. The efficacy of adjuvant AIs compared to tamoxifen is lower in obese postmenopausal women. Therefore, we aimed to identify whether the effect of AIs on estradiol, leptin, insulin, and IGF-1 serum levels with respect to the status of the obesity in breast cancer patients. Methods: A total of 34 postmenopausal breast cancer patients treated with adjuvant AIs were enrolled in the study. Pretreatment and 3 months after treatment body weight, height, waist-to-hip (WHR) ratio and body mass index (BMI) were recorded. Blood samples for serum estradiol, leptin, insulin and IGF-1 were drawn after 12 hour starvation and stored in – 70o before and 3 months after the onset of AI treatment. Results: Median age and BMI were 61 years (range 49-84) and 31 (range 22-43), respectively. 18 (%52.9) patients were treated with letrozole and 16 (%47.1) patients were treated with anastrazole. There was no change in the 3 months period in weight, BMI and WHR. Estradiol levels were decreased significantly between the baseline and the 3rd month (p<0.01). There was a slight increase in the leptin levels between the basal and 3rd month (p>0.05). No significant change was detected in insulin and IGF-1 levels in the follow-up period. In the multivariate regression model, there was no difference between the effect of letrozole and anastrazole on estradiol levels. Pretreatment BMI did not alter the effect of AIs on estradiol levels. The only factor related with the effect of the AIs is the pretreatment estradiol levels. Conclusions: This study shows that the suppression of estrogen in obese breast cancer patients with AIs at the standard doses may not be different from non-obese patients. Further researches may show us other mechanisms for the obesity-related factors to improve outcome with aromatase inhibition in obese breast cancer patients.