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1.
Mar Mamm Sci ; 37(4): 1428-1453, 2021 Oct.
Article in English | MEDLINE | ID: mdl-34690418

ABSTRACT

Availability of preferred salmonid prey and a sufficiently quiet acoustic environment in which to forage are critical to the survival of resident killer whales (Orcinus orca) in the northeastern Pacific. Although piscivorous killer whales rely on echolocation to locate and track prey, the relationship between echolocation, movement, and prey capture during foraging by wild individuals is poorly understood. We used acoustic biologging tags to relate echolocation behavior to prey pursuit and capture during successful feeding dives by fish-eating killer whales in coastal British Columbia, Canada. The significantly higher incidence and rate of echolocation prior to fish captures compared to afterward confirms its importance in prey detection and tracking. Extremely rapid click sequences (buzzes) were produced before or concurrent with captures of salmon at depths typically exceeding 50 m, and were likely used by killer whales for close-range prey targeting, as in other odontocetes. Distinctive crunching and tearing sounds indicative of prey-handling behavior occurred at relatively shallow depths following fish captures, matching concurrent observations that whales surfaced with fish prior to consumption and often shared prey. Buzzes and prey-handling sounds are potentially useful acoustic signals for estimating foraging efficiency and determining if resident killer whales are meeting their energetic requirements.

2.
J Acoust Soc Am ; 139(3): 1149-57, 2016 Mar.
Article in English | MEDLINE | ID: mdl-27036251

ABSTRACT

Killer whale acoustic behavior has been extensively investigated; however, most studies have focused on pulsed calls and whistles. This study reports the production of low-frequency signals by killer whales at frequencies below 300 Hz. Recordings were made in Iceland and Norway when killer whales were observed feeding on herring and no other marine mammal species were nearby. Low-frequency sounds were identified in Iceland and ranged in duration between 0.14 and 2.77 s and in frequency between 50 and 270 Hz, well below the previously reported lower limit for killer whale tonal sounds of 500 Hz. Low-frequency sounds appeared to be produced close in time to tail slaps, which are indicative of feeding attempts, suggesting that these sounds may be related to a feeding context. However, their precise function is unknown, and they could be the by-product of a non-vocal behavior rather than a vocal signal deliberately produced by the whales. Although killer whales in Norway exhibit similar feeding behavior, this sound has not been detected in recordings from Norway to date. This study suggests that, like other delphinids, killer whales produce low-frequency sounds, but further studies will be required to understand whether similar sounds exist in other killer whale populations.


Subject(s)
Vocalization, Animal/classification , Whale, Killer/classification , Whale, Killer/physiology , Acoustics , Animals , Atlantic Ocean , Feeding Behavior , Signal Processing, Computer-Assisted , Sound Spectrography , Time Factors
3.
Proc Biol Sci ; 282(1798): 20141595, 2015 Jan 07.
Article in English | MEDLINE | ID: mdl-25411449

ABSTRACT

Anthropogenic noise can have negative effects on animal behaviour and physiology. However, noise is often introduced systematically and potentially provides information for navigation or prey detection. Here, we show that grey seals (Halichoerus grypus) learn to use sounds from acoustic fish tags as an indicator of food location. In 20 randomized trials each, 10 grey seals individually explored 20 foraging boxes, with one box containing a tagged fish, one containing an untagged fish and all other boxes being empty. The tagged box was found after significantly fewer non-tag box visits across trials, and seals revisited boxes containing the tag more often than any other box. The time and number of boxes needed to find both fish decreased significantly throughout consecutive trials. Two additional controls were conducted to investigate the role of the acoustic signal: (i) tags were placed in one box, with no fish present in any boxes and (ii) additional pieces of fish, inaccessible to the seal, were placed in the previously empty 18 boxes, making possible alternative chemosensory cues less reliable. During these controls, the acoustically tagged box was generally found significantly faster than the control box. Our results show that animals learn to use information provided by anthropogenic signals to enhance foraging success.


Subject(s)
Auditory Perception , Predatory Behavior , Animals , Female , Fisheries , Fishes , Male , Seals, Earless/physiology
4.
Behav Ecol ; 34(3): 373-386, 2023.
Article in English | MEDLINE | ID: mdl-37192928

ABSTRACT

In cooperative species, human-induced rapid environmental change may threaten cost-benefit tradeoffs of group behavioral strategies that evolved in past environments. Capacity for behavioral flexibility can increase population viability in novel environments. Whether the partitioning of individual responsibilities within social groups is fixed or flexible across populations is poorly understood, despite its relevance for predicting responses to global change at the population and species levels and designing successful conservation programs. We leveraged bio-logging data from two populations of fish-eating killer whales (Orcinus orca) to quantify patterns of fine-scale foraging movements and their relationships with demography. We reveal striking interpopulation differences in patterns of individual foraging behavior. Females from the endangered Southern Resident (SRKW) population captured less prey and spent less time pursuing prey than SRKW males or Northern Resident (NRKW) females, whereas NRKW females captured more prey than NRKW males. The presence of a calf (≤3 years) reduced the number of prey captured by adult females from both populations, but disproportionately so for SRKW. SRKW adult males with a living mother captured more prey than those whose mother had died, whereas the opposite was true for NRKW adult males. Across populations, males foraged in deeper areas than females, and SRKW captured prey deeper than NRKW. These population-level differences in patterns of individual foraging behavior challenge the existing paradigm that females are the disproportionate foragers in gregarious resident killer whales, and demonstrate considerable variation in the foraging strategies across populations of an apex marine predator experiencing different environmental stressors.

5.
Anim Cogn ; 15(4): 725-30, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22367156

ABSTRACT

This is the first report of tool-using behaviour in a wild brown bear (Ursus arctos). Whereas the use of tools is comparatively common among primates and has also been documented in several species of birds, fishes and invertebrates, tool-using behaviours have so far been observed in only four species of non-primate mammal. The observation was made and photographed while studying the behaviour of a subadult brown bear in south-eastern Alaska. The animal repeatedly picked up barnacle-encrusted rocks in shallow water, manipulated and re-oriented them in its forepaws, and used them to rub its neck and muzzle. The behaviour probably served to relieve irritated skin or to remove food-remains from the fur. Bears habitually rub against stationary objects and overturn rocks and boulders during foraging and such rubbing behaviour could have been transferred to a freely movable object to classify as tool-use. The bear exhibited considerable motor skills when manipulating the rocks, which clearly shows that these animals possess the advanced motor learning necessary for tool-use. Advanced spatial cognition and motor skills for object manipulation during feeding and tool-use provide a possible explanation for why bears have the largest brains relative to body size of all carnivores. Systematic research into the cognitive abilities of bears, both in captivity and in the wild, is clearly warranted to fully understand their motor-learning skills and physical intelligence related to tool-use and other object manipulation tasks.


Subject(s)
Tool Use Behavior , Ursidae/psychology , Alaska , Animals , Animals, Wild/psychology
6.
Hautarzt ; 63(10): 808-11, 2012 Oct.
Article in German | MEDLINE | ID: mdl-22552842

ABSTRACT

A 43-year-old man with cutaneous and pulmonary sarcoidosis was treated with fumaric acid esters (Fumaderm®) for 11 months because of the cutaneous lesions. During the treatment the cutaneous lesions and pulmonary changes vanished completely. In addition, serum angiotensin converting enzyme (ACE) levels normalized after end of therapy. This case report is one of a few examples of the successful treatment of cutaneous and pulmonary sarcoidosis with fumaric acid esters (Fumaderm®).


Subject(s)
Dermatitis/drug therapy , Fumarates/administration & dosage , Sarcoidosis/drug therapy , Adult , Dermatitis/diagnosis , Dimethyl Fumarate , Humans , Male , Sarcoidosis/diagnosis , Sarcoidosis, Pulmonary/diagnosis , Sarcoidosis, Pulmonary/drug therapy , Treatment Outcome
7.
Ann Surg Oncol ; 18(2): 514-20, 2011 Feb.
Article in English | MEDLINE | ID: mdl-20839060

ABSTRACT

BACKGROUND: The status of the sentinel lymph node is an important predictor for survival in melanoma patients, but it is still unclear if early removal of micrometastases by sentinel lymph node dissection (SLND) alters survival. A large series of melanoma patients from a single center with long-term follow-up was analyzed with regard to a possible effect of SLND on the prognosis. MATERIALS AND METHODS: A total of 673 consecutive melanoma patients were assessed treated in our center either without SLND (377 patients, pre-SLN group, between January 1995 and March 2000) or with SLND (296 patients, SLN group, between April 2000 and March 2003). The median follow-up was 64.0 months in the pre-SLN and 72.5 months in the SLN group. RESULTS: The pre-SLN group and SLN group did not differ significantly with regard to characteristics of the primary melanoma thickness and ulceration, sex, and age. Kaplan-Meier analyses showed a significantly better recurrence-free survival (P < .001), distant metastases free survival (P = .006), and overall survival (P = .049) for patients of the SLN group; the 5-year melanoma-specific survival rates were 80.3% in pre-SLN patients and 84.8% in SLN patients. Initial metastases in the in-transit region and distant locations were of similar frequency in the pre-SLN and SLN groups (P = .191 and P = .959, respectively), but initial regional lymph node metastases were significantly more frequent in the pre-SLN group (P < .001). CONCLUSIONS: Our data point toward a subgroup of melanoma patients who might have a prognostic benefit from SLN.


Subject(s)
Lymph Node Excision , Melanoma/mortality , Neoplasm Recurrence, Local/mortality , Sentinel Lymph Node Biopsy , Skin Neoplasms/mortality , Adolescent , Adult , Aged , Aged, 80 and over , Child , Female , Follow-Up Studies , Humans , Lymphatic Metastasis , Male , Melanoma/pathology , Melanoma/surgery , Middle Aged , Neoplasm Recurrence, Local/pathology , Neoplasm Recurrence, Local/surgery , Neoplasm Staging , Prognosis , Skin Neoplasms/pathology , Skin Neoplasms/surgery , Survival Rate , Young Adult
8.
Naturwissenschaften ; 97(5): 513-8, 2010 May.
Article in English | MEDLINE | ID: mdl-20213302

ABSTRACT

A few species of mammals produce group-specific vocalisations that are passed on by learning, but the function of learned vocal variation remains poorly understood. Resident killer whales live in stable matrilineal groups with repertoires of seven to 17 stereotyped call types. Some types are shared among matrilines, but their structure typically shows matriline-specific differences. Our objective was to analyse calls of nine killer whale matrilines in British Columbia to test whether call similarity primarily reflects social or genetic relationships. Recordings were made in 1985-1995 in the presence of focal matrilines that were either alone or with groups with non-overlapping repertoires. We used neural network discrimination performance to measure the similarity of call types produced by different matrilines and determined matriline association rates from 757 encounters with one or more focal matrilines. Relatedness was measured by comparing variation at 11 microsatellite loci for the oldest female in each group. Call similarity was positively correlated with association rates for two of the three call types analysed. Similarity of the N4 call type was also correlated with matriarch relatedness. No relationship between relatedness and association frequency was detected. These results show that call structure reflects relatedness and social affiliation, but not because related groups spend more time together. Instead, call structure appears to play a role in kin recognition and shapes the association behaviour of killer whale groups. Our results therefore support the hypothesis that increasing social complexity plays a role in the evolution of learned vocalisations in some mammalian species.


Subject(s)
Social Behavior , Stereotyped Behavior , Vocalization, Animal , Whale, Killer/psychology , Animal Identification Systems , Animals , British Columbia , Family , Female , Learning , Male , Nerve Net , Whale, Killer/physiology
9.
J Acoust Soc Am ; 128(5): EL205-10, 2010 Nov.
Article in English | MEDLINE | ID: mdl-21110527

ABSTRACT

This study reports that killer whales, the largest dolphin, produce whistles with the highest fundamental frequencies ever reported in a delphinid. Using wide-band acoustic sampling from both animal-attached (Dtag) and remotely deployed hydrophone arrays, ultrasonic whistles were detected in three Northeast Atlantic populations but not in two Northeast Pacific populations. These results are inconsistent with analyses suggesting a correlation of maximum frequency of whistles with body size in delphinids, indicate substantial intraspecific variation in whistle production in killer whales, and highlight the importance of appropriate acoustic sampling techniques when conducting comparative analyses of sound repertoires.


Subject(s)
Ultrasonics , Vocalization, Animal/physiology , Whale, Killer/physiology , Animals , Body Size/physiology , Hearing/physiology
10.
Hautarzt ; 61(12): 1052-5, 2010 Dec.
Article in German | MEDLINE | ID: mdl-20824263

ABSTRACT

A 19-year-old patient presented with epidermodysplasia verruciformis (EV). In this genodermatosis, pathogenetic factors such as infection by human papilloma viruses as well as sun exposure are considered responsible for the malignant transformation of EV lesions to skin cancer within decades. So far, several therapeutic strategies have been unsatisfactory. In our case HPV 5b was detected and the associated skin lesions were successfully treated with imiquimod 5% cream.


Subject(s)
Adjuvants, Immunologic/administration & dosage , Aminoquinolines/administration & dosage , Epidermodysplasia Verruciformis/drug therapy , Facial Dermatoses/drug therapy , Adjuvants, Immunologic/adverse effects , Administration, Topical , Aminoquinolines/adverse effects , Biopsy , Consanguinity , DNA Probes, HPV , Drug Administration Schedule , Drug Eruptions/etiology , Epidermodysplasia Verruciformis/diagnosis , Epidermodysplasia Verruciformis/genetics , Epidermodysplasia Verruciformis/pathology , Facial Dermatoses/diagnosis , Facial Dermatoses/genetics , Facial Dermatoses/pathology , Humans , Imiquimod , Male , Oligonucleotide Array Sequence Analysis , Papillomavirus Infections/complications , Papillomavirus Infections/diagnosis , Skin/pathology
11.
Hautarzt ; 60(2): 131-6, 2009 Feb.
Article in German | MEDLINE | ID: mdl-18654750

ABSTRACT

Intravascular lymphoma (IVL) is a rare subtype of extranodal large-B-cell lymphoma, histologically characterized by accumulation of clonal lymphocytes in small vessels of different organs. Overall survival is usually poor. The clinical manifestations are highly variable, depending on the involved organs. Cutaneous and neurological involvement is frequent; the cutaneous symptoms are heterogeneous with erythema, erythematous papules and plaques, generalized telangiectases and lesions resembling panniculitis or Kaposi sarcoma. IVL may also be limited to the skin; this entity is included the current classifications. We present here two patients with two different variants of IVL. One showed only skin involvement with panniculitis-like induration and responded well to therapy with Rituximab-CHOP (Rituximab plus Cyclophosphamide, Doxorubicin, Vincristine, Prednisolone). The other patient had distinctive cutaneous and neurological symptoms which did not respond to therapy. By means of these two patients, we present the heterogeneity of IVL and discuss current aspects of diagnosis and treatment.


Subject(s)
Antibodies, Monoclonal/administration & dosage , Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Lymphoma, B-Cell/diagnosis , Lymphoma, B-Cell/drug therapy , Panniculitis/diagnosis , Panniculitis/drug therapy , Vascular Neoplasms/diagnosis , Vascular Neoplasms/drug therapy , Aged , Antibodies, Monoclonal, Murine-Derived , Cyclophosphamide/administration & dosage , Doxorubicin/administration & dosage , Humans , Male , Panniculitis/etiology , Prednisone/administration & dosage , Rituximab , Vincristine/administration & dosage
12.
Hautarzt ; 60(3): 229-32, 2009 Mar.
Article in German | MEDLINE | ID: mdl-18663422

ABSTRACT

A 47-year-old immunocompetent man presented with a nodule on the right side of the upper lip that appeared suddenly and grew rapidly. Histological examination was consistent with the diagnosis of keratoacanthoma which is often associated with immunosuppression. Low-risk HPV type 11 was detected in the PCR analysis. While formerly one often waited for spontaneous regression of keratoacanthomas, today one routinely treats them as a well-differentiated squamous cell carcinoma. Complete surgical excision was not possible in our patient because of the size of the tumor. Radiation with a cumulative dose of 30 Gray (15 sessions of 2 Gray) led to complete remission. In addition to ultraviolet exposure, trauma, genetic factors and chemical carcinogens, HPV should be considered as a possible cofactor in the etiology of keratoacanthoma.


Subject(s)
Human papillomavirus 11 , Keratoacanthoma/diagnosis , Lip Diseases/diagnosis , Papillomavirus Infections/diagnosis , Biopsy , Combined Modality Therapy , Diagnosis, Differential , Human papillomavirus 11/genetics , Humans , Immunocompetence , Keratoacanthoma/pathology , Keratoacanthoma/radiotherapy , Keratoacanthoma/surgery , Lip Diseases/pathology , Lip Diseases/radiotherapy , Lip Diseases/surgery , Male , Middle Aged , Papillomavirus Infections/pathology , Papillomavirus Infections/radiotherapy , Papillomavirus Infections/surgery , Polymerase Chain Reaction , Radiotherapy, Adjuvant , Risk Factors , Skin/pathology
13.
Hautarzt ; 60(9): 743-8, 2009 Sep.
Article in German | MEDLINE | ID: mdl-19151961

ABSTRACT

Treatment of autoimmune bullous diseases, especially of the pemphigus diseases, regularly requires the use of immunosuppressive drugs, often with insufficient clinical benefit but considerable side effects. A variety of autoimmune diseases (such as rheumatoid arthritis, lupus erythematosus, pemphigus vulgaris) have been successfully treated with rituximab, a chimeric monoclonal antibody against CD20, leading to a transient depletion of B cells. We report on three patients with pemphigus foliaceus who responded to rituximab after failing multiple other immunosuppressive therapies. We also examine the controversial issue of continuation therapy with rituximab in detail.


Subject(s)
Antibodies, Monoclonal/therapeutic use , Pemphigus/drug therapy , Pemphigus/pathology , Adult , Antibodies, Monoclonal, Murine-Derived , Female , Humans , Immunologic Factors/therapeutic use , Male , Middle Aged , Rituximab , Treatment Outcome
14.
Int J Oral Maxillofac Surg ; 37(1): 66-9, 2008 Jan.
Article in English | MEDLINE | ID: mdl-17822876

ABSTRACT

Oral lichen planus (OLP) is a chronic inflammatory mucosal disease of unknown etiology. Usually asymptomatic, the disorder is occasionally complicated by extensive painful erosions. Topical corticosteroids are the mainstay of treatment, but a new topical therapy with tacrolimus has been described previously. The aim of the current study was to examine the expression of heat-shock protein 70 (HSP70) in biopsy specimens from 11 OLP lesions before and after topical treatment with tacrolimus. Immunostaining was performed with anti-HSP70 antibody as the primary layer. Clinically, there was a rapid improvement with topical tacrolimus treatment in 10 out of the 11 patients. The moderate increase in HSP70 expression after treatment with tacrolimus was not significant. It was concluded that topical tacrolimus has no effect on the expression of HSP70 in OLP.


Subject(s)
HSP70 Heat-Shock Proteins/analysis , Immunosuppressive Agents/administration & dosage , Lichen Planus, Oral/drug therapy , Tacrolimus/administration & dosage , Administration, Topical , Aged , Animals , Female , Humans , Immunosuppressive Agents/adverse effects , Lichen Planus, Oral/metabolism , Lichen Planus, Oral/pathology , Male , Middle Aged , Mouth Mucosa/drug effects , Rabbits , Tacrolimus/adverse effects
15.
PLoS One ; 13(7): e0200287, 2018.
Article in English | MEDLINE | ID: mdl-30001369

ABSTRACT

Many baleen whales undertake annual fasting and feeding cycles, resulting in substantial changes in their body condition, an important factor affecting fitness. As a measure of lipid-store body condition, tissue density of a few deep diving marine mammals has been estimated using a hydrodynamic glide model of drag and buoyancy forces. Here, we applied the method to shallow-diving humpback whales (Megaptera novaeangliae) in North Atlantic and Antarctic feeding aggregations. High-resolution 3-axis acceleration, depth and speed data were collected from 24 whales. Measured values of acceleration during 5 s glides were fitted to a hydrodynamic glide model to estimate unknown parameters (tissue density, drag term and diving gas volume) in a Bayesian framework. Estimated species-average tissue density (1031.6 ± 2.1 kg m-3, ±95% credible interval) indicates that humpback whale tissue is typically negatively buoyant although there was a large inter-individual variation ranging from 1025.2 to 1043.1 kg m-3. The precision of the individual estimates was substantially finer than the variation across different individual whales, demonstrating a progressive decrease in tissue density throughout the feeding season and comparably high lipid-store in pregnant females. The drag term (CDAm-1) was estimated to be relatively high, indicating a large effect of lift-related induced drag for humpback whales. Our results show that tissue density of shallow diving baleen whales can be estimated using the hydrodynamic gliding model, although cross-validation with other techniques is an essential next step. This method for estimating body condition is likely to be broadly applicable across a range of aquatic animals and environments.


Subject(s)
Body Composition , Humpback Whale/anatomy & histology , Animals , Bayes Theorem , Body Composition/physiology , Feeding Behavior , Female , Humpback Whale/physiology , Hydrodynamics , Male , Models, Biological , Swimming/physiology
16.
Mov Ecol ; 5: 3, 2017.
Article in English | MEDLINE | ID: mdl-28239473

ABSTRACT

BACKGROUND: We sought to quantitatively describe the fine-scale foraging behavior of northern resident killer whales (Orcinus orca), a population of fish-eating killer whales that feeds almost exclusively on Pacific salmon (Oncorhynchus spp.). To reconstruct the underwater movements of these specialist predators, we deployed 34 biologging Dtags on 32 individuals and collected high-resolution, three-dimensional accelerometry and acoustic data. We used the resulting dive paths to compare killer whale foraging behavior to the distributions of different salmonid prey species. Understanding the foraging movements of these threatened predators is important from a conservation standpoint, since prey availability has been identified as a limiting factor in their population dynamics and recovery. RESULTS: Three-dimensional dive tracks indicated that foraging (N = 701) and non-foraging dives (N = 10,618) were kinematically distinct (Wilks' lambda: λ16 = 0.321, P < 0.001). While foraging, killer whales dove deeper, remained submerged longer, swam faster, increased their dive path tortuosity, and rolled their bodies to a greater extent than during other activities. Maximum foraging dive depths reflected the deeper vertical distribution of Chinook (compared to other salmonids) and the tendency of Pacific salmon to evade predators by diving steeply. Kinematic characteristics of prey pursuit by resident killer whales also revealed several other escape strategies employed by salmon attempting to avoid predation, including increased swimming speeds and evasive maneuvering. CONCLUSIONS: High-resolution dive tracks reconstructed using data collected by multi-sensor accelerometer tags found that movements by resident killer whales relate significantly to the vertical distributions and escape responses of their primary prey, Pacific salmon.

17.
Sci Rep ; 6: 33228, 2016 09 14.
Article in English | MEDLINE | ID: mdl-27624220

ABSTRACT

Structural materials used for safety critical applications require high strength and simultaneously high resistance against crack growth, referred to as damage tolerance. However, the two properties typically exclude each other and research efforts towards ever stronger materials are hampered by drastic loss of fracture resistance. Therefore, future development of novel ultra-strong bulk materials requires a fundamental understanding of the toughness determining mechanisms. As model material we use today's strongest metallic bulk material, namely, a nanostructured pearlitic steel wire, and measured the fracture toughness on micron-sized specimens in different crack growth directions and found an unexpected strong anisotropy in the fracture resistance. Along the wire axis the material reveals ultra-high strength combined with so far unprecedented damage tolerance. We attribute this excellent property combination to the anisotropy in the fracture toughness inducing a high propensity for micro-crack formation parallel to the wire axis. This effect causes a local crack tip stress relaxation and enables the high fracture toughness without being detrimental to the material's strength.

18.
Rheumatol Ther ; 3(2): 271-290, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27804088

ABSTRACT

OBSErve Germany was the first observational study of belimumab as add-on treatment for systemic lupus erythematosus (SLE) in routine clinical care in Germany, retrospectively collecting data from 102 SLE patients, 6 months before and after belimumab initiation. Most patients had moderate or severe SLE and several SLE manifestations. After 6 months of belimumab treatment, 78% of patients showed an improvement in overall disease activity of at least 20% in their physician's judgment and for 42% of patients the improvement was at least 50%. Similar results were observed for the most common manifestations: arthritis, fatigue, rash, alopecia, increased anti-dsDNA antibody levels, and low complement. The SLE Disease Activity Index (SLEDAI/SELENA-SLEDAI) decreased from 10.6 to 5.6 (n = 65), with other indices also showing improvement. A notable dose reduction was seen for concomitant oral corticosteroids, from 13.7 to 7.6 mg/day overall (n = 91), and from 17.5 to 8.6 mg/day in patients with a high corticosteroid dose at belimumab initiation (≥7.5 mg; n = 63). Six patients discontinued belimumab therapy within 6 months. Overall, belimumab showed promising results for SLE patients in real-world settings. After 6 months of belimumab treatment, disease activity and corticosteroid use were reduced. The discontinuation rate was low and belimumab appeared to be well tolerated. Funding GlaxoSmithKline UK.

19.
Biochim Biophys Acta ; 1145(1): 180-2, 1993 Jan 18.
Article in English | MEDLINE | ID: mdl-8422410

ABSTRACT

It has become common practice to analyse the sugar transport kinetics from initial uptake rates in Saccharomyces cerevisiae cells with Eadie-Hofstee plots. These plots often demonstrate a nonlinear behaviour. They have been resolved incorrectly into two quasilinear components indicating the presence of (at least) two uptake systems or components, with Km values differing by a factor of about 10. This graphical analysis neglects the obvious additivity of the two hypothetical systems and is therefore in error. A more efficient way to determine kinetic parameters from initial uptake experiments is to use computer-assisted nonlinear regression analysis.


Subject(s)
Glucose/metabolism , Saccharomyces cerevisiae/metabolism , Kinetics , Models, Biological , Regression Analysis
20.
Biochim Biophys Acta ; 1325(1): 126-34, 1997 Apr 03.
Article in English | MEDLINE | ID: mdl-9106490

ABSTRACT

The analysis of initial glucose uptake in Saccharomyces cerevisiae at 25 degrees, 20 degrees, 15 degrees and 10 degrees C by computer-assisted nonlinear regression analysis predicts two transport systems. The first demonstrates Michaelis-Menten kinetics and the second shows first order behaviour. The activation energies of these two systems were calculated by the Arrhenius equation at four different growth phases, namely early exponential (EE), middle exponential (ME2), late exponential (LE) and early stationary (ES) with 2% glucose in the batch medium. The activation energies calculated from the V(m) values in EE, ME, LE and ES growth phases were 15.8 +/- 1.7, 13.5 +/- 1.0, 15.1 +/- 0.8 and 13.5 +/- 0.7 kcal/mol. These values are in agreement with activation energies calculated for the first mechanism, facilitated diffusion, which is the mechanism deduced from countertransport experiments. The activation energies derived for the second transport system from the first order rate constants in cells grown to EE, ME2, LE and ES were 8.0 +/- 2.1, 8.1 +/- 1.3, 9.6 +/- 3.0 and 7.5 +/- 2.6 kcal/mol. These values are still significantly higher than for free diffusion of glucose in water and lower as predicted for passage of glucose through the lipid phase. Therefore, we assume in addition to carrier-mediated facilitated diffusion the entrance of glucose into the cell through a pore.


Subject(s)
Glucose/metabolism , Monosaccharide Transport Proteins/metabolism , Saccharomyces cerevisiae/metabolism , Biological Transport , Kinetics , Models, Chemical , Subcellular Fractions/metabolism , Temperature , Thermodynamics
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