Long-term efficacy and safety of nusinersen in adults with 5q spinal muscular atrophy: a prospective European multinational observational study

Background

Evidence for the efficacy of nusinersen in adults with 5q-associated spinal muscular atrophy (SMA) has been demonstrated up to a period of 16 months in relatively large cohorts but whereas patients reach a plateau over time is still to be demonstrated. We investigated the efficacy and safety of nusinersen in adults with SMA over 38 months, the longest time period to date in a large cohort of patients from multiple clinical sites.

Methods

Our prospective, observational study included adult patients with SMA from Germany, Switzerland, and Austria (July 2017 to May 2022). All participants had genetically-confirmed, 5q-associated SMA and were treated with nusinersen according to the label. The total Hammersmith Functional Motor Scale Expanded (HFMSE) and Revised Upper Limb Module (RULM) scores, and 6-min walk test (6 MWT; metres), were recorded at baseline and 14, 26, and 38 months after treatment initiation, and pre and post values were compared. Adverse events were also recorded.

Findings

Overall, 389 patients were screened for eligibility and 237 were included. There were significant increases in all outcome measures compared with baseline, including mean HFMSE scores at 14 months (mean difference 1.72 [95% CI 1.19-2.25]), 26 months (1.20 [95% CI 0.48-1.91]), and 38 months (1.52 [95% CI 0.74-2.30]); mean RULM scores at 14 months (mean difference 0.75 [95% CI 0.43-1.07]), 26 months (mean difference 0.65 [95% CI 0.27-1.03]), and 38 months (mean difference 0.72 [95% CI 0.25-1.18]), and 6 MWT at 14 months (mean difference 30.86 m [95% CI 18.34-43.38]), 26 months (mean difference 29.26 m [95% CI 14.87-43.65]), and 38 months (mean difference 32.20 m [95% CI 10.32-54.09]). No new safety signals were identified.

Interpretation

Our prospective, observational, long-term (38 months) data provides further real-world evidence for the continuous efficacy and safety of nusinersen in a large proportion of adult patients with SMA.

Funding

Financial support for the registry from Biogen, Novartis and Roche.

[Certification by the German Society for Neurorehabiliation, DGNR : Performance and quality of the "Centers for weaning from a ventilator in early neurological and neurosurgical rehabilitation"]

BACKGROUND

Certification of centers for weaning from a ventilator in neurological neurosurgical early rehabilitation (NNER) by the German Society for Neurorehabilitation (DGNR) is possible since 1 October 2021.

OBJECTIVE

The results of certification of facilities in the first year after starting the procedure are presented.

MATERIAL AND METHODS

As part of the certification process 28 criteria are assessed including a set of mandatory characteristics of the facility. The criteria are divided into structural criteria (i = 7), diagnostic criteria (i = 6), personnel criteria (i = 3), internal organization criteria (i = 7), and quality management criteria (i = 5).

RESULTS

A total of 13 centers were certified in the first year, with a combined total of 283 beds for weaning from a ventilator in the NNER and served 2278 persons to be weaned from a ventilator in the year before certification, with a median of 134 per facility (range 44-414). Only rarely was weaning unsuccessful, requiring conversion to home mechanical ventilation before discharge (invasive home mechanical ventilation median per facility 10 persons, range 2-25; non-invasive home mechanical ventilation median 0 persons, range 0-57). A high level of process and structural quality was documented for the certified centers: across all areas of assessment, the individual certification criteria were met in the vast majority of cases (median degree of complete fulfilment 86%) or met with improvement potentials documented by the auditors (median 11%).

CONCLUSION

Successful weaning in NNER and a high level of process and structural quality can be demonstrated by the certification results of centers that follow this integrative approach to weaning from a ventilator in a NNER setting.

Effect of mechanical insufflation-exsufflation for ineffective cough on weaning duration in diseases of the peripheral or central nervous system (MEDINE): study protocol for a randomised controlled trial in a neurological weaning centre

INTRODUCTION

Patients with neurological or neurosurgical disease can suffer from impaired cough, which may result in life-threatening retention of tracheobronchial secretions, atelectasis, pneumonia and finally death. Due to a lack of alternatives and pathophysiological plausibility, the application of mechanical insufflation-exsufflation (MI-E) has already become international standard care in neuromuscular disease and spinal cord injury although a lack of evidence for efficacy. High-quality studies to support the use of MI-E in neurological and neurosurgical patients during weaning from mechanical ventilation are missing. The goal of this exploratory study is to display the effect size of MI-E intervention on the duration of mechanical ventilation and additional outcomes.

METHODS AND ANALYSIS

One hundred adult patients with a cough deficiency or retention of secretion admitted to a neurological intensive care unit (ICU) are planned to be recruited for this randomised controlled trial. Patients are randomised 1:1 to receive either MI-E or best standard care. Observation will take place until discharge from the hospital, death or end of the study period. The primary endpoint of this trial is the duration of mechanical ventilation from randomisation until successful weaning. The outcome will be analysed with Kaplan-Meier estimation and competing risks analyses. Secondary endpoint is the proportion of patients with successful weaning. Further outcomes will include the incidence of hospital-acquired pneumonia, mortality, decannulation rate, length of stay on the ICU and the total score of the Glasgow Coma Scale.

ETHICS AND DISSEMINATION

The study was approved by the Medical Ethics Committee of the University of Oldenburg. The findings of this study will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

DRKS00020981.

[The Respiratory Therapist in Neurology An Evolving Specialization in Germany]

In Germany, nurses, physiotherapists and speech and language therapists follow a qualifying training for about 1,5 years to become respiratory therapists (RTs). With respect to neurological illness, RTs diagnose and treat disorders of respiration, cough and swallowing as well as a retention of tracheobronchial secretions. There is an increasing demand for RTs in neurology, in neurointensive care and in neurological and neurosurgical early rehabilitation. The certification of specialized centers for weaning in neurological and neurosurgical early rehabilitation was introduced by the German Society for Neurorehabilitation (DGNR) in 2021. As a certification criterion it includes the employment of a respiratory therapists. In neurological organizations treating critically and severely ill patients, RTs work at an important interdisciplinary intersection of physicians, nurses and therapists. RTs are qualified to train teams, patients and family caregivers and to establish care structures for critically and severely ill neurological patients. Due to the complexity of neurological illnesses RTs working in neurological institutions need specific qualification. Specific training for RTs in neurology and neurorehabilitation might improve care for critically and severely ill neurological patients. Further professionalization of RT in Germany requires standardizing curricula, a professional society for RTs and, finally, academization.

Observing many researchers using the same data and hypothesis reveals a hidden universe of uncertainty

This study explores how researchers' analytical choices affect the reliability of scientific findings. Most discussions of reliability problems in science focus on systematic biases. We broaden the lens to emphasize the idiosyncrasy of conscious and unconscious decisions that researchers make during data analysis. We coordinated 161 researchers in 73 research teams and observed their research decisions as they used the same data to independently test the same prominent social science hypothesis: that greater immigration reduces support for social policies among the public. In this typical case of social science research, research teams reported both widely diverging numerical findings and substantive conclusions despite identical start conditions. Researchers' expertise, prior beliefs, and expectations barely predict the wide variation in research outcomes. More than 95% of the total variance in numerical results remains unexplained even after qualitative coding of all identifiable decisions in each team's workflow. This reveals a universe of uncertainty that remains hidden when considering a single study in isolation. The idiosyncratic nature of how researchers' results and conclusions varied is a previously underappreciated explanation for why many scientific hypotheses remain contested. These results call for greater epistemic humility and clarity in reporting scientific findings.

Improved upper limb function in non-ambulant children with SMA type 2 and 3 during nusinersen treatment: a prospective 3-years SMArtCARE registry study

Background

The development and approval of disease modifying treatments have dramatically changed disease progression in patients with spinal muscular atrophy (SMA). Nusinersen was approved in Europe in 2017 for the treatment of SMA patients irrespective of age and disease severity. Most data on therapeutic efficacy are available for the infantile-onset SMA. For patients with SMA type 2 and type 3, there is still a lack of sufficient evidence and long-term experience for nusinersen treatment. Here, we report data from the SMArtCARE registry of non-ambulant children with SMA type 2 and typen 3 under nusinersen treatment with a follow-up period of up to 38 months.

Methods

SMArtCARE is a disease-specific registry with data on patients with SMA irrespective of age, treatment regime or disease severity. Data are collected during routine patient visits as real-world outcome data. This analysis included all non-ambulant patients with SMA type 2 or 3 below 18 years of age before initiation of treatment. Primary outcomes were changes in motor function evaluated with the Hammersmith Functional Motor Scale Expanded (HFMSE) and the Revised Upper Limb Module (RULM).

Results

Data from 256 non-ambulant, pediatric patients with SMA were included in the data analysis. Improvements in motor function were more prominent in upper limb: 32.4% of patients experienced clinically meaningful improvements in RULM and 24.6% in HFMSE. 8.6% of patients gained a new motor milestone, whereas no motor milestones were lost. Only 4.3% of patients showed a clinically meaningful worsening in HFMSE and 1.2% in RULM score.

Conclusion

Our results demonstrate clinically meaningful improvements or stabilization of disease progression in non-ambulant, pediatric patients with SMA under nusinersen treatment. Changes were most evident in upper limb function and were observed continuously over the follow-up period. Our data confirm clinical trial data, while providing longer follow-up, an increased number of treated patients, and a wider range of age and disease severity.

Psychophysiological Effects of Biographical Interventions in People With Unresponsive Wakefulness Syndrome and Minimally Conscious State

Background

Various music interventions can evoke favorable behavioral responses or physiological reactions in people with disorders of consciousness (DOC), such as coma, unresponsive wakefulness syndrome (UWS), and minimally conscious state (MCS). However, it appears that no study thus far has investigated the effects of music on the endocrine system of people with DOC.

Objective

This explorative study aimed to investigate the effects of biographical music and biographical language on the physiological and endocrine systems of people with UWS and MCS.

Method

A cohort of 20 people with DOC (10 women, 10 men; age range 19–77) received 20 min of biographical music and biographical language. Before and afterward, they were exposed to silence. Physiological and hormonal measurements were conducted before, during, and after the interventions.

Results

Paired t-tests showed a significant decrease of salivary cortisol in the condition with biographical language interventions.

Conclusion

Biographical interventions can modulate reactions in the endocrine system in people with DOC. Further studies are needed to establish whether and how individuals living with DOC show psychoneuroendocrine responses to music and other arts-based interventions.

[The certification of centers for weaning from mechanical ventilation in neurological and neurosurgical early rehabilitation by the German Society for Neurorehabilitation]

Die Zertifizierung von Zentren für Beatmungsentwöhnung in der neurologisch-neurochirurgischen Frührehabilitation durch die Deutsche Gesellschaft für Neurorehabilitation (DGNR) ist ab dem 01.10.2021 möglich. Die Zertifizierungskriterien beschreiben ein Anforderungsprofil, das für eine fachgerechte und qualitätsgesicherte Versorgung von Beatmungspatienten in der neurologisch-neurochirurgischen Frührehabilitation (NNFR) steht. Das Zertifikat berücksichtigt die strukturellen Unterschiede der in der NNFR tätigen Einrichtungen und kann sowohl durch Facheinrichtungen als auch durch Frührehabilitationsabteilungen an Akutkrankenhäusern erworben werden. Die Durchführung der Zertifizierung erfolgt analog zur Zertifizierung von Stroke-Units der Deutschen Schlaganfall-Gesellschaft in Zusammenarbeit mit dem TÜV Rheinland. Zunächst sendet die Einrichtung den Erhebungsbogen an den TÜV Rheinland. Anschließend erfolgt die Begehung durch einen vom TÜV Rheinland gestellten leitenden Auditor und einen Fachauditor der DGNR. Deren Bericht wird dem Zertifizierungsausschuss der DGNR vorgelegt zur Erteilung einer Empfehlung oder Ablehnung der Zertifizierung. Die Zertifizierung schafft objektive Kriterien, die die Rolle der Neurologie in der Beatmungsmedizin in Deutschland beschreiben. So erleichtert sie den Dialog mit anderen beatmungsmedizinischen Disziplinen und ebnet den Weg für die Diskussion mit Politikern, Kostenträgern und nicht zuletzt Betroffenenverbänden über Behandlungsinhalte und -kapazitäten.

Damage-Induced Calcium Signaling and Reactive Oxygen Species Mediate Macrophage Activation in Zebrafish

Immediately after a wound, macrophages are activated and change their phenotypes in reaction to danger signals released from the damaged tissues. The cues that contribute to macrophage activation after wounding in vivo are still poorly understood. Calcium signaling and Reactive Oxygen Species (ROS), mainly hydrogen peroxide, are conserved early wound signals that emanate from the wound and guide neutrophils within tissues up to the wound. However, the role of these signals in the recruitment and the activation of macrophages is elusive. Here we used the transparent zebrafish larva as a tractable vertebrate system to decipher the signaling cascade necessary for macrophage recruitment and activation after the injury of the caudal fin fold. By using transgenic reporter lines to track pro-inflammatory activated macrophages combined with high-resolutive microscopy, we tested the role of Ca²⁺ and ROS signaling in macrophage activation. By inhibiting intracellular Ca²⁺ released from the ER stores, we showed that macrophage recruitment and activation towards pro-inflammatory phenotypes are impaired. By contrast, ROS are only necessary for macrophage activation independently on calcium. Using genetic depletion of neutrophils, we showed that neutrophils are not essential for macrophage recruitment and activation. Finally, we identified Src family kinases, Lyn and Yrk and NF-κB as key regulators of macrophage activation in vivo, with Lyn and ROS presumably acting in the same signaling pathway. This study describes a molecular mechanism by which early wound signals drive macrophage polarization and suggests unique therapeutic targets to control macrophage activity during diseases.

[Weaning in neurological and neurosurgical early rehabilitation-Results from the "WennFrüh" study of the German Society for Neurorehabilitation]

Neurologisch-neurochirurgische Frührehabilitanden sind klinisch oft so schwer betroffen, dass sie neben der frührehabilitativen Behandlung auch von der mechanischen Beatmung entwöhnt werden müssen. In einer Umfrage der Deutschen Gesellschaft für Neurorehabilitation (DGNR) wurden neurologische Weaningzentren gebeten, Informationen zu Strukturmerkmalen ihrer Einrichtung, ihrer personellen und apparativen Ausstattung sowie basierend auf anonymen Daten zu Fallzahl und Behandlungsergebnis zur Verfügung zu stellen. Es nahmen 36 Weaningeinheiten aus 11 Bundesländern mit insgesamt 496 Betten teil. Von 2516 erfassten Weaningfällen im Jahr 2019 wurden 2097 (83,3 %) primär erfolgreich entwöhnt und nur 120 (4,8 %) mussten mit Heimbeatmung entlassen werden. Die Mortalität in dieser Stichprobe lag bei 11,0 % (n = 276). Die Erhebung zeigt, dass das prolongierte Weaning in der neurologisch-neurochirurgischen Frührehabilitation ein wichtiger und erfolgreicher Bestandteil der Versorgung schwerstkranker Patienten darstellt.

[COVID-19 pandemic: structured expansion of ventilation capacities using home respirators]

Due to the current COVID-19 pandemic there is a need for a rapid increase in intensive care and ventilation capacities. Delivery times for additional intensive care respirators are currently not foreseeable. An option to increase ventilation capacities not only for COVID-19, but for all patients requiring mechanical ventilation is to use home respirators. Home respirators are turbine respirators, so they can usually be operated without high-pressure oxygen connections and can therefore also be used in areas outside the classical intensive care medical infrastructure. Due to their limited technical features, home respirators are not suitable for the treatment of severely affected patients but can be used for weaning after respiratory improvement, which means that intensive care respirators are available again more quickly. Respiratory therapists are specially trained nurses or therapists in the field of out of hospital ventilation and can independently use home ventilation respirators, for example for weaning in the intensive care unit. Thus, they relieve intensive care nursing staff in the pandemic. Due to the COVID-19 pandemic medical students from the Oldenburg University are currently being trained in operating home respirators to provide basic support in the hospital if necessary.

Implications of Testing a Zinc-Oxygen Battery with Zinc Foil Anode Revealed by Operando Gas Analysis

Zinc-oxygen batteries are seen as promising energy storage devices for future mobile and stationary applications. Introducing them as secondary battery is hindered by issues at both the anode and cathode. Research efforts were intensified during the past two decades, mainly focusing on catalyst materials for the cathode. Thereby, zinc foil was almost exclusively used as the anode in electrochemical testing in the lab-scale as it is easy to apply and shall yield reproducible results. However, it is well known that zinc metal reacts with water within the electrolyte to form hydrogen. It is not yet clear how the evolution of hydrogen is affecting the performance results obtained thereof. Herein, we extend the studies and the understanding about the evolution of hydrogen at zinc by analyzing the zinc-oxygen battery during operation. By means of electrochemical measurements, operando gas analysis, and anode surface analysis, we elucidate that the rate of the evolution of hydrogen scales with the current density applied, and that the roughness of the anode surface, that is, the pristine state of the zinc foil surface, affects the rate as well. In the end, we propose a link between the evolution of hydrogen and the unwanted impact on the actual electrochemical performance that might go unnoticed during testing. Thereof, we elucidate the consequences that arise for the working principle and the testing of materials for this battery type.

[Hypersalivation - Update of the S2k guideline (AWMF) in short form]

Hypersalivation describes a relatively excessive salivary flow, which wets the patient himself and his surroundings. It may result because of insufficient oro-motor function, dysphagia, decreased central control and coordination. This update presents recent changes and innovation in the treatment of hypersalivation.Multidisciplinary diagnostic and treatment evaluation is recommended already at early stage and focus on dysphagia, saliva aspiration, and oro-motor deficiencies. Clinical screening tools and diagnostics such as fiberoptic endoscopic evaluation of swallowing generate important data on therapy selection and control. Many cases profit from swallowing therapy programmes in order to activate compensation mechanisms as long compliances is given. In children with hypotonic oral muscles, oral stimulation plates can induce a relevant symptom release because of the improved lip closure. The pharmacologic treatment improved for pediatric cases as glycopyrrolate fluid solution (Sialanar^®) is now indicated for hypersalivation within the E. U. The injection of botulinum toxin into the salivary glands has shown safe and effective results with long lasting saliva reduction. Here, a phase III trial is completed for Incobotulinum toxin A and, in the U. S., is indicated for the treatment of adult patients with chronic hypersalivation. Surgical treatment should be reserved for isolated cases. External radiation is judged as a safe and effective therapy when using modern 3 D techniques to minimize tissue damage. Therapy effects and symptom severity has to be followed, especially in cases with underlying neurodegenerative disease.

[Neurological and neurosurgical early rehabilitation in Lower Saxony and Bremen]

INTRODUCTION

We analyzed the delivery of healthcare services among patients in neurological and neurosurgical early rehabilitation programmes in the German states of Lower Saxony and Bremen.

METHODS

Patients´applications and admissions for neurological and neurosurgical early rehabilitation in Lower Saxony and Bremen were recorded during a period of two weeks both in November 2015 as well as 2016. The proportion of patients admitted to early rehabilitation within a six-week-period after disease onset was calculated. In addition, factors influencing the probability of admission were investigated.

RESULTS

Only 45 % of all patients transferred from a primary neurological / neurosurgical unit to an early rehabilitation facility in Lower Saxony / Bremen were successfully admitted. The probability of admission fell when patients were colonized with multi-drug resistant bacteria (21 % in comparison), in particular Methicillin-resistant Staphylococcus aureus (MRSA) with an admission rate of only 13 %. Deleterious effects were also observed in patients dependent on hemodialysis (20 %), or those with a primary diagnosis of polyneuropathy / Guillain-Barré-Syndrome (33 %) or hypoxic brain damage (37 %), as well as patients on mechanical ventilation (37 %). Patients had a higher probability of being admitted with the primary diagnoses of subarachnoid hemorrhage (52 %) or stroke (51 %). Age, Early Rehabilitation Index (ERI), monitoring, presence of tracheostomy, dysphagia, orientation or behavioral disturbances had no influence on the probability of admission, as well as other primary diagnoses or the number of admissions in one or more rehabilitation centers.

CONCLUSION

Over one-half of the patients applying for admission to neurological / neurosurgical early rehabilitation facilities in Lower Saxony and Bremen were not admitted. Apparently, the capacity of early rehabilitation treatment in these two German states is not optimal.

Passive Ballistic Microbunching of Nonultrarelativistic Electron Bunches Using Electromagnetic Wakefields in Dielectric-Lined Waveguides

Temporally modulated electron beams have a wide array of applications ranging from the generation of coherently enhanced electromagnetic radiation to the resonant excitation of electromagnetic wakefields in advanced-accelerator concepts. Likewise producing low-energy ultrashort microbunches could be useful for ultrafast electron diffraction and new accelerator-based light-source concepts. In this Letter we propose and experimentally demonstrate a passive microbunching technique capable of forming a picosecond bunch train at ∼6  MeV. The method relies on the excitation of electromagnetic wakefields as the beam propagates through a dielectric-lined waveguide. Owing to the nonultrarelativistic nature of the beam, the induced energy modulation eventually converts into a density modulation as the beam travels in a following free-space drift. The modulated beam is further accelerated to ∼20  MeV while preserving the imparted density modulation.

Adhesion and activation of platelets from subjects with coronary artery disease and apparently healthy individuals on biomaterials

On the basis of the clinical studies in patients with coronary artery disease (CAD) presenting an increased percentage of activated platelets, we hypothesized that hemocompatibility testing utilizing platelets from healthy individuals may result in an underestimation of the materials' thrombogenicity. Therefore, we investigated the interaction of polymer-based biomaterials with platelets from CAD patients in comparison to platelets from apparently healthy individuals. In vitro static thrombogenicity tests revealed that adherent platelet densities and total platelet covered areas were significantly increased for the low (polydimethylsiloxane, PDMS) and medium (Collagen) thrombogenic surfaces in the CAD group compared to the healthy subjects group. The area per single platelet-indicating the spreading and activation of the platelets-was markedly increased on PDMS treated with PRP from CAD subjects. This could not be observed for collagen or polytetrafluoroethylene (PTFE). For the latter material, platelet adhesion and surface coverage did not differ between the two groups. Irrespective of the substrate, the variability of these parameters was increased for CAD patients compared to healthy subjects. This indicates a higher reactivity of platelets from CAD patients compared to the healthy individuals. Our results revealed, for the first time, that utilizing platelets from apparently healthy donors bears the risk of underestimating the thrombogenicity of polymer-based biomaterials.

S3-Guidelines for the Treatment of Inflammatory Breast Disease during the Lactation Period: AWMF Guidelines, Registry No. 015/071 (short version) AWMF Leitlinien-Register Nr. 015/071 (Kurzfassung)

Breastfeeding is widely acknowledged to be the best and most complete form of nutrition for healthy infants born at term and is associated with numerous benefits in terms of infants' health, growth, immunity and development. However, breastfeeding problems often result in early weaning. Standardized treatment recommendations for breastfeeding-related diseases are necessary to optimize the care offered to breastfeeding women. Evidence and consensus based guidelines for the treatment of puerperal mastitis, sore nipples, engorgement and blocked ducts were developed on the initiative of the National Breastfeeding Committee. These guidelines were developed in accordance with the criteria set up by the Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften (AWMF), the Association of Scientific Medical Societies in Germany. The recommendations were drawn up by an interdisciplinary group of experts and were based on a systematic search and evaluation of the literature but also took clinical experience into account. Additionally good clinical practice (GCP) in terms of expert opinion was formulated in cases where scientific investigations could not be performed or were not aimed for. This article presents a summary of the recommendations of the S3-guidelines.

Influence of sugars on blue light-induced synthesis of chlorophyll in cultured plant cells

In supension cultured tobacco cells only blue light induces and maintains chlorophyll synthesis if the liquid nutrient medium is supplemented with sucrose. The yield per gram fresh weight is closely correlated with the energy fluence rate of blue light, but not with the initial amount of sucrose added to the medium (3-12 g/l). The uptake of sucrose by the cells proceeds with a constant rate over the growth period independently of the initial amount leading within 10-25 days to sucrose-free media. Under these conditions the cells continue to synthesize chlorophyll for about 10 days. This limitation is overcome by adding sucrose to the medium at equal time intervals thus establishing a constant sugar level beyond the growth period. In contrast, glucose as carbon source cannot adequately replace sucrose in inducing and maintaining blue light-induced chlorophyll synthesis. Depending on the initial amount (3-10 g/l) this sugar is rapidly disappearing from the medium within 1-5 days after inoculation of the cells. It apparently serves as a preferential source of energy and carbon skeletons thus suppressing chlorophyll synthesis. On the other hand, glucose combined with sucrose in the medium brings about the characteristic induction and accumulation of chlorophyll in blue light which is observed with sucrose as the sole carbon source.