HIV and SARS-CoV-2 co-infection: cross-sectional findings from a German 'hotspot'.

PURPOSE: This study aimed to determine the proportion of people living with HIV with anti-SARS-CoV-2 IgG antibodies in a sample from a large single HIV center in Munich, Germany, after the first phase of the coronavirus pandemic and to infer the prevalence of SARS-CoV-2 co-infection in people living with HIV. METHODS: Prospective sub-study of the ongoing ArcHIV cohort between May and July 2020. Anti-SARS-CoV-2 IgG antibodies were measured using the recomWell SARS-CoV-2 IgG ELISA (Mikrogen, Neuried, Germany); positive and borderline results were re-tested using the recomLine SARS-CoV-2 IgG immunoassay (Mikrogen, Neuried, Germany). Demographic and medical data were extracted from the electronic patient files. RESULTS: Overall, 500 people living with HIV were included in the study (83% male, median age 51 years). Three participants had been diagnosed with COVID-19 prior to study inclusion. Of those, nine were confirmed positive for SARS-CoV-2 IgG antibodies, resulting in an estimated seroprevalence (accounting for sensitivity and specificity of the test) of 1.5% (CI 95%: 0.69; 3.13) for the entire study sample, and 2.2% (CI 95%: 1.1; 3.9) for the subset of the Munich citizens. There were no marked differences for people living with HIV with and without SARS-CoV-2 co-infection. CONCLUSION: The seroprevalence of SARS-CoV-2 co-infection in people living with HIV as found in our study does not seem to exceed previous reports from general populations of 'hot-sport' areas; comparative data from the Munich population can be expected to be published soon. Our data also highlight, once more, the need to do confirmatory testing on positive samples to minimize the impact of false-positive results.

[Outpatient palliative medicine : Attitudes in the care of palliative emergencies. Prospective questionnaire-based investigation]. / Ambulante Palliativmedizin : Einstellungen in der Versorgung palliativer Notfälle. Prospektive Fragebogenuntersuchung.

BACKGROUND: The right to adequate outpatient palliative care has existed for several years in Germany. In recent years outpatient palliative care has developed very positively. Nevertheless, in emergency situations paramedics and emergency physicians were often included in the care of palliative care of patients. The aim of our study was to investigate the cooperation between outpatient palliative care teams and the emergency medical services. Another aim was to identify structural realities and based on these to discuss the possibilities in the optimization of outpatient palliative medical emergency situations. METHODS: A standardized self-designed questionnaire was distributed to specialized outpatient palliative care teams (SPCS) in Germany. For this purpose, closed and open questions (mixed methods) were used. The evaluation was carried out according to the questionnaire categories in quantitative and qualitative forms. The questionnaire was subdivided into general information and specific questions. RESULTS: The survey response rate was 79% from a total of 81 SPCS in 2011. The following standards in palliative emergency care were recommended: (1) early integration of outpatient palliative care services and basic outpatient palliative care systems, (2) end-of-life discussions, (3) defined emergency medical documents, emergency drug boxes, do not attempt resuscitation orders and (4) emergency medical training (physicians and paramedics). CONCLUSION: Outpatient palliative care in Germany has developed very positively during the last years; however, there are still deficits in terms of optimal patient care, one of which refers to the treatment of palliative care emergencies. In this context, optimization in the cooperation between outpatient palliative care services and emergency medical services should be discussed.

Nucleon Spin and Momentum Decomposition Using Lattice QCD Simulations.

We determine within lattice QCD the nucleon spin carried by valence and sea quarks and gluons. The calculation is performed using an ensemble of gauge configurations with two degenerate light quarks with mass fixed to approximately reproduce the physical pion mass. We find that the total angular momentum carried by the quarks in the nucleon is J_{u+d+s}=0.408(61)_{stat}(48)_{syst} and the gluon contribution is J_{g}=0.133(11)_{stat}(14)_{syst}, giving a total of J_{N}=0.54(6)_{stat}(5)_{syst} that is consistent with the spin sum. For the quark intrinsic spin contribution, we obtain 1/2ΔΣ_{u+d+s}=0.201(17)_{stat}(5)_{syst}. All quantities are given in the modified minimal subtraction scheme at 2 GeV. The quark and gluon momentum fractions are also computed and add up to ⟨x⟩_{u+d+s}+⟨x⟩_{g}=0.804(121)_{stat}(95)_{syst}+0.267(12)_{stat}(10)_{syst}=1.07(12)_{stat}(10)_{syst}, thus satisfying the momentum sum.

[Is supplemental ear acupuncture for surgical tooth removal with local anesthesia effective? : A pilot study]. / Ist die Supplementierung der Ohrakupunktur bei operativer Zahnentfernung in Lokalanästhesie effektiv? : Eine Pilotstudie.

BACKGROUND: The application of ear acupuncture can contribute to a reduction of acute pain. Data on the application of ear acupuncture following oral surgery in odontology is insufficient. OBJECTIVE: This study investigated the effectiveness of ear acupuncture as an auxiliary analgesic treatment in addition to local anesthesia for operative tooth removal. METHODS: In this prospective open non-randomized pilot study (in accordance with the CONSORT publication) 2 cohorts of 50 patients each with the indications for an operative tooth removal either with or without the application of ear acupuncture in addition to local anesthesia with articain were observed. Patients were allocated to the groups according to their preference. Pain intensity while resting and while chewing was recorded as the primary parameter for a period of 10 days. The secondary parameters were the subjective experience of anxiety and symptoms, such as headaches, dizziness and nausea. RESULTS: The two groups did not differ significantly with respect to demographic variables or the use of local anesthetics. At the various measurement intervals, pain intensity while resting or chewing differed significantly between the two groups (ANOVA, p = 0.004, p = 0.007, respectively). Furthermore, the experience of anxiety (ANOVA, p = 0.0001), the number of patients taking analgesics (χ2-test, p = 0.017) and the total postoperative consumption of analgesics (t-test, 0.001) revealed significant differences. In both groups the numerical rating scales (NRS) for postoperative headaches, dizziness and nausea were low. DISCUSSION AND CONCLUSION: Despite a potential bias and methodological limitations of the study design, the results of this investigation suggest that ear acupuncture influences the experience of pain and anxiety in the postoperative period after tooth removal. As a treatment method with low adverse effects ear acupuncture can contribute to postoperative pain control, especially in patients with preoperative anxiety.

Effects of ropivacaine, bupivacaine and sufentanil in colon and pancreatic cancer cells in vitro.

The perioperative period is supposed to be a vulnerable period for cancer progression. Results of clinical studies indicate that the use of regional anesthesia can influence and improve oncological outcome of cancer patients. Uncontrolled cell proliferation and resistance to apoptotic cell death are important characteristics of solid tumors. The aim of this study was to investigate the effects of the clinically used local anesthetics ropivacaine or bupivacaine and the opioid analgesic sufentanil on cell proliferation, cell cycle distribution and apoptosis of colon (HT 29 and SW 480) and pancreatic (PaTu 8988t and PANC 1) cancer cell lines in vitro. Cell proliferation was measured by Cell Proliferation ELISA BrdU Assay. Apoptosis was analyzed by annexin V staining and cell cycle distribution was detected by flow cytometry. Ropivacaine, bupivacaine and sufentanil did not change apoptosis rate and cell cycle distribution in clinically concentration. Only high concentrations of ropivacaine or bupivacaine revealed antiproliferative potency. Protective effects of epidural anesthesia observed in clinical studies seem not to be based on direct effects of these drugs on cancer cells.

[Simulation as possible training for palliative emergencies: prospective initial data analysis of participants from two simulation training sessions]. / Simulation als Möglichkeit zum Training palliativer Notfälle : Prospektive erste Datenanalyse von Teilnehmern zweier Simulationstrainings.

BACKGROUND: Palliative emergencies describe an acute situation in patients with a life-limiting illness. At present defined curricula for prehospital emergency physician training for palliative emergencies are limited. Simulation-based training (SBT) for such palliative emergency situations is an exception both nationally and internationally. AIM: This article presents the preparation of recommendations in the training and development of palliative care emergency situations. MATERIAL AND METHODS: A selected literature search was performed using PubMed, EMBASE, Medline and the Cochrane database (1990-2013). Reference lists of included articles were checked by two reviewers. Data of the included articles were extracted, evaluated und summarized. In the second phase the participants of two simulated scenarios of palliative emergencies were asked to complete an anonymous 15-item questionnaire. The results of the literature search and the questionnaire-based investigation were compared and recommendations were formulated based on the results. RESULTS: Altogether 30 eligible national and international articles were included. Overall, training curricula in palliative emergencies are currently being developed nationally and internationally but are not yet widely integrated into emergency medical training and education. In the second part of the investigation, 25 participants (9 male, 16 female, 20 physicians and 5 nurses) were included in 4 multiprofessional emergency medical simulation training sessions. The most important interests of the participants were the problems for training and further education concerning palliative emergencies described in the national and international literature. CONCLUSION: The literature review and the expectations of the participants underlined that the development and characteristics of palliative emergencies will become increasingly more important in outpatient emergency medicine. All participants considered palliative care to be very important concerning the competency for end-of-life decisions in palliative patients. For this reason, special curricula and simulation for dealing with palliative care patients and special treatment decisions in emergency situations seem to be necessary.

Lipid emulsion pretreatment has different effects on mepivacaine and bupivacaine cardiac toxicity in an isolated rat heart model.

BACKGROUND: The use of lipid emulsions to reduce cardiac toxicity of local anaesthetics (LAs) has shown success in experimental studies and some clinical cases, and thus has been implemented in clinical practice. However, lipid treatment is usually given after the occurrence of neurological or cardiovascular symptoms of systemic intoxication. The aim of this study was to determine if pretreatment with lipid emulsion reduces cardiac toxicity produced by bupivacaine or mepivacaine. METHODS: Isolated rat hearts were perfused with or without lipid emulsion (0.25 ml kg(-1) min(-1)) before administration of equipotent doses of bupivacaine (250 µM) or mepivacaine (1000 µM). Haemodynamic parameters and times from start of perfusion LA to a 1 min period of asystole and recovery were determined. RESULTS: Pretreatment with lipid emulsion extended the time until occurrence of asystole and decreased times to recovery in bupivacaine-induced cardiac toxicity but not in mepivacaine-induced cardiac toxicity compared with control. Lipid pretreatment impaired rate-pressure product recovery in mepivacaine-intoxicated hearts. CONCLUSIONS: This study confirms that pretreatment with a lipid emulsion reduces cardiac toxicity of LAs. The efficacy of pretreatment with lipid emulsion was LA-dependent, so pharmacokinetic properties, such as lipophilicity, might influence the effects of lipid emulsion pretreatment.

Surgical pleth index-guided remifentanil administration reduces remifentanil and propofol consumption and shortens recovery times in outpatient anaesthesia.

BACKGROUND: The surgical pleth index (SPI) is an index based on changes in plethysmographic characteristics that correlate with the balance between the sympathetic and parasympathetic nervous system. It has been proposed as a measure of the balance between nociception and anti-nociception. The goal of this study was to test whether it could be used to titrate remifentanil in day-case anaesthesia. METHODS: A total of 170 outpatients were given total i.v. anaesthesia with propofol and remifentanil. The patients were randomized to have the remifentanil dose either adjusted according to the SPI (SPI group) or to clinical parameters (control group). The propofol dose was adjusted according to entropy in both groups. The consumption of anaesthetic drugs, recovery times, and complications were compared. RESULTS: The mean [standard deviation (SD)] remifentanil and propofol infusion rates in the SPI and control groups were 0.06 (0.04) vs 0.08 (0.05) µg kg(-1) min(-1) and 6.0 (2.1) vs 7.5 (2.2) mg kg(-1) h(-1), respectively (both P<0.05). The mean (SD) times to eye opening were -0.08 (4.4) and 3.5 (4.3) min and to extubation were 1.2 (4.4) and 4.4 (4.5) min in the SPI and control groups, respectively (both P<0.05). There was no difference between the groups with regard to satisfaction with the anaesthetic or intensity of postoperative pain. No patient reported intraoperative awareness. CONCLUSIONS: Adjusting the remifentanil dosage according to the SPI in outpatient anaesthesia reduced the consumption of both remifentanil and propofol and resulted in faster recovery.

An international two-stage genome-wide search for schizophrenia susceptibility genes.

Schizophrenia is thought to be a multifactorial disease with complex mode of inheritance. Using a two-stage strategy for another complex disorder, a number of putative IDDM-susceptibility genes have recently been mapped. We now report the results of a two-stage genome-wide search for genes conferring susceptibility to schizophrenia. In stage I, model-free linkage analyses of large pedigrees from Iceland, a geographical isolate, revealed 26 loci suggestive of linkage. In stage II, ten of these were followed-up in a second international collaborative study comprising families from Austria, Canada, Germany, Italy, Scotland, Sweden, Taiwan and the United States. Potential linkage findings of stage I on chromosomes 6p, 9 and 20 were observed again in the second sample. Furthermore, in a third sample from China, fine mapping of the 6p region by association studies also showed evidence for linkage or linkage disequilibrium. Combining our results with other recent findings revealed significant evidence for linkage to an area distal of the HLA region on chromosome 6p. However, in a fourth sample from Europe, the 6p fine mapping finding observed in the Chinese sample could not be replicated. Finally, evidence suggestive of locus heterogeneity and oligogenic transmission in schizophrenia was obtained.

[Rapid release fentanyl administration forms. Comments of the Working Group on Tumor Pain of the German Pain Society]. / Schnell freisetzende Fentanylapplikationsformen. Stellungnahme des Arbeitskreises Tumorschmerz der Deutschen Schmerzgesellschaft.

The spectrum of indications for rapid release fentanyl preparations is controversial. For this reason the Working Group on Tumor Pain will formulate comments on how to deal with these substances. Breakthrough pain should receive individualized therapy; therefore, the use of opioids of various galenic formulations seems to be advisable. New rapid release fentanyl preparations are suitable for alleviating spontaneous breakthrough pain in tumor patients due to a rapid but short-acting effect. However, a prior optimization of the analgesic basis medication is absolutely necessary. Uncontrolled prescription for non-cancer pain must be criticized due to the problem of addiction. The medical profession should be informed about the benefits of rapid release fentanyl preparations but must also be made aware of the risk of a rapid development of addiction and tolerance. A self-commitment of the pharmaceutical industry to waive advertising for the dangerous off-label use would be desirable. In the opinion of the Working Group on Tumor Pain the use of fentanyl should be openly discussed and further scientific investigations are imperative with the aim of formulating clear recommendations.

[Patients at the end of life in the intensive care unit: cultural aspects of accompaniment]. / Patienten am Lebensende auf der Intensivstation: Kulturelle Aspekte der Begleitung.

The accompaniment of people in the face of death offers insights into dimensions which are mostly not seen in ordinary life. These insights also exist in intensive care in German hospitals and are highly relevant in medical decision making. End-of-life decisions in particular often determine medical, cultural and spiritual aspects concerning medical treatment and therapeutic targets and if necessary new therapy targets. The following article especially illuminates cultural aspects and their characteristics in patients at the end of life in the intensive care unit.

[Anesthesiological acute pain therapy in Germany: telephone-based survey]. / Anästhesiologische Akutschmerztherapie in Deutschland: Telefonbasierte Umfrage.

INTRODUCTION: The last survey of anesthesiological acute pain therapy in Germany was conducted in 1999. Since then new organisational as well as therapeutic aspects have developed. Amongst others the operation and procedures key (OPS) figure 8-919 complex acute pain therapy has been introduced in the German medical billing system, with the restriction that it cannot currently be redeemed. There is an ongoing debate on the role of epidural analgesia in acute pain therapy and new oral medication concepts have been established. Therefore a survey of the present state of acute pain therapy in Germany was conducted. METHODS: Based on a list of all 1,356 hospitals in Germany a randomized list of 412 hospitals was generated. Out of these 412 hospitals those with anesthesiology departments (378 hospitals) were contacted via telephone and asked to participate in the survey. Out of the 378 hospitals 285 (75.4 %) agreed to take part. The survey consisted of a questionnaire containing closed and open questions regarding organisational and therapeutic aspects of acute pain therapy. The ethics committee of the University of Regensburg rated the survey as not being subject to approval due to the lack of personal patient data. RESULTS: Of the participating hospitals 183 (64.2 %) had an acute pain service (APS) and of these 107 (58.5 %) met the quality criteria of the OPS 8-919. This figure however, was only consistently documented by 40 (37 %) APSs. Epidural analgesia (EA) was offered by 275 (96.5 %) hospitals and patient-controlled intravenous analgesia (PCA) by 255 (89.5 %). Likewise, 255 (89.5 %) hospitals used controlled-released opioids in acute pain therapy. Concerning EA, the medications most used were sufentanil as an opioid and ropivacaine as a local anesthetic in255 (92.7 %) of the hospitals with EA for sufentanil and 253 (92 %] for ropivacaine. An EA was offered on regular wards in 240 (87.3 %) hospitals. Uncertainty existed about concrete limits for coagulation values before removal of an epidural catheter. The opioid most utilized in PCA was piritramide with some hospitals using morphine or oxycodone (92.2 %, 9.4 % and 9.4 %, respectively). Other opioids, such as hydromorphone and tramadol were rarely used and remifentanil was not used at all. Oral medication was widely used with metamizole being the non-opioid analgesic and oxycodone/naloxone the controlled-release opioid being prescribed the most. New antiepileptic drugs, such as gabapentin or pregabalin were rarely employed in acute pain therapy. CONCLUSIONS: Since 1999 the number of hospitals that have implemented an APS has risen from 36.1 % to 64.2 %. The lack of consistent documentation of the OPS 8-919 will probably not increase the likelihood that it will become redeemable in the near future. Certain therapy methods, such as EA and PCA were still well established with oral therapy gaining in significance. The uncertainty regarding limits for coagulation values before removal of an epidural catheter could perhaps be reduced by a statement from the German Society of Anesthesia and Intensive Care.

[Perioperative care of palliative patients by the anesthetist : medical, psychosocial and ethical challenges]. / Perioperative Betreuung von Palliativpatienten durch den Anästhesisten : Medizinische, psychosoziale und ethische Herausforderungen.

Anesthetists will encounter palliative patients in the daily routine as palliative patients undergo operations and interventions as well, depending on the state of the disease. The first challenge for anesthetists will be to recognize the patient as being palliative. In the course of further treatment it will be necessary to address the specific problems of this patient group. Medical problems are optimized symptom control and the patient's pre-existing medication. In the psychosocial domain, good communication skills are expected of anesthetists, especially during the preoperative interview. Ethical conflicts exist with the decision-making process for surgery and the handling of perioperative do-not-resuscitate orders. This article addresses these areas of conflict and the aim is to enable anesthetists to provide the best possible perioperative care to this vulnerable patient group with the goal to maintain quality of life and keep postoperative recovery as short as possible.

[Interprofessional education in pain management: development strategies for an interprofessional core curriculum for health professionals in German-speaking countries]. / Interprofessionelle Lehre in der Schmerzmedizin : Möglichkeiten und Strategien für die Entwicklung eines professionsübergreifenden Curriculums im deutschsprachigen Raum.

The care of patients, suffering from acute, chronic, or malignant pain, requires systematic and interprofessional collaboration between all team members to ensure a holistic approach to pain management. In doing so, the different professions are often in a competitive, tense, or dependent relationship resulting from a lack of precise definitions and concepts regarding their responsibilities in the wide field of pain management. Considering pain management as a whole, we can define numerous interfaces concerning competencies and tasks which may open up some new perspectives on concepts of interprofessional education (IPE). Internationally, there have been many attempts to establish concepts of interprofessional education, and it is considered a great challenge to improve continuing medical education. However, interdisciplinary subjects like pain management may benefit from it. Apart from enhancing specialized knowledge, interprofessional education aims to consider the different roles, skills, and responsibilities as well as interprofessional strategies of decision-making. In Germany, only a few efforts have been made with regard to interprofessional pain education. In the following paper, different challenges, tasks, and roles within the field of pain management are discussed in the sense of potential areas of collaboration in the context of interprofessional education. Against this background, the Regensburg model for interprofessional pain management education is described as one national program to enhance the effectiveness of pain management.

[Inpatient pain consultation service at a university hospital: a retrospective analysis of patient characteristics and the rate of the implementation of recommendations]. / Stationäre Schmerzkonsile einer universitären Schmerzambulanz : Eine retrospektive Analyse der Patientencharakteristika und der Umsetzungsrate der Empfehlungen.

BACKGROUND: The aim of this study was to conduct an audit of a university inpatient pain consultation service and to examine the quality and the implementation of the recommended therapeutic measures. Factors that influenced the implementation should be identified. PATIENTS AND METHODS: All inpatients treated by the consultation service in the years 2009 and 2010 were analyzed retrospectively. Demographic patient characteristics as well as quality parameters of the consultation service and pharmacological and non-pharmacological recommendations and their implementation were analyzed. RESULTS: In total 1,048 requests for the consultation service were processed of which 39.7% of the requests were for patients with acute pain, 33.8% with chronic and 19.9% with tumor-associated pain. Measures recommended most were medication, physiotherapy and psychological treatment. Recommended medications were actually prescribed in more than 80%, physiotherapy recommended in about 75% and psychological treatment recommended in 47% of the cases. Only a few influencing factors for the implementation of the recommended measures could be identified. CONCLUSION: Many different pain states are seen in an inpatient pain consultation service. The recommendations given are implemented in most cases especially concerning the medication.

[Naloxone-induced pulmonary edema. Case report with review of the literature and critical evaluation]. / Naloxoninduziertes Lungenödem. Fallbericht mit Literaturübersicht und kritischer Bewertung.

A case of pulmonary edema after the administration of naloxone for laparoscopic splenectomy is reported. Previous reports of naloxone-induced pulmonary edema are listed and reviewed. The clinical course is compared to other forms of non-cardiogenic pulmonary edema. Uncertainty remains about the underlying pathophysiological process and the true impact of naloxone on the development of pulmonary edema.

[Age rationing : means of resource allocation in healthcare systems]. / Altersrationierung : Mittel zur Ressourcenverteilung im Gesundheitswesen.

The necessity of limiting resource in healthcare systems is becoming increasingly more evident. The population has requirements especially in the field of healthcare which are principally unlimited. However, there are only limited financial resources which can be used to satisfy the wishes of the population. For this reason rationing models are being discussed increasingly more often. One example of these models is called age rationing which means that defined services are only offered to patients up to a particular age. The aim of this article is to discuss the model of age rationing in the context of an optimized use of resources in the healthcare system.

[Palliative care oriented therapy for all patients : recommendations of an expert circle]. / Palliativmedizinisch orientierte Therapieansätze für alle Patienten : Empfehlungen eines Expertenkreises.

BACKGROUND: Since 2011 palliative care has been a compulsory part of the German medical study course (so-called Q13 palliative and pain medicine). Palliative care content does not, however, as often taught, have to focus only on patients in the so-called palliative stages of disease. The aim of this investigation was to encourage a discussion concerning the integration of palliative care aspects into general medical treatment. METHODS: For data collection an open discussion of the main topics by experts in palliative medical care was used. The main outcome measures and recommendations included responses regarding current practices related to expert opinions, national and international literature and one case report. The literature search was performed using the databases "PubMed", "Medline" and "Google" (1990-2011). RESULTS: As an important consensus, the following recommendations for optimization of inpatient and outpatient care were: (1) integration of aspects of palliative care into medical curricula of all disciplines, (2) palliative care content should be extended to the general optimization of therapy for all patients, (3) palliative medicine should be part of the everyday medical practice in all disciplines and (4) palliative medicine should not be isolated as "death medicine" or medicine of the dying patient. CONCLUSIONS: Palliative care treatment is increasingly becoming integrated into medical education and into medical curricula of all disciplines. Palliative ideas and goals are focussed on patients in the so-called palliative stages of disease. Furthermore, palliative medicine is often described as the medicine of dying patients. As a result of this study it seems to make sense to extend palliative care aspects to all patients and to all patient care. The extent to which such opportunities exist and such health care is economically feasible remains to be the subject of further clinical studies.

Nuclear membrane dynamics.

Our understanding of nuclear membrane trafficking and protein targeting has increased significantly, due to newly developed assays and tools. We present a conceptual framework for thinking about protein targeting to the inner nuclear membrane, and discuss nuclear envelope assembly in terms of vesicle binding to chromatin, vesicle fusion, structural attachments to the inner membrane, and the mitotic regulation of these attachments.

A new function for the gamma-tubulin ring complex as a microtubule minus-end cap.

Microtubule nucleation from centrosomes involves a lockwasher-shaped protein complex containing gamma-tubulin, named the gamma-tubulin ring complex (gammaTuRC). Here we investigate the mechanism by which the gammaTuRC nucleates microtubules, using a direct labelling method to visualize the behaviour of individual gammaTuRCs. A fluorescently-labelled version of the gammaTuRC binds to the minus ends of microtubules nucleated in vitro. Both gammaTuRC-mediated nucleation and binding of the gammaTuRC to preformed microtubules block further minus-end growth and prevent microtubule depolymerization. The gammaTuRC therefore acts as a minus-end-capping protein, as confirmed by electron-microscopic examination of gold-labelled gammaTuRCs. These data support a nucleation model for gammaTuRC function that involves capping of microtubules.