Showing papers by "Utrecht University published in 1994"

A mutation in the RET proto-oncogene associated with multiple endocrine neoplasia type 2B and sporadic medullary thyroid carcinoma

Abstract: Multiple endocrine neoplasia type 2 (MEN 2) comprises three clinically distinct, dominantly inherited cancer syndromes. MEN 2A patients develop medullary thyroid carcinoma (MTC) and phaeochromocytoma. MEN 2B patients show in addition ganglioneuromas of the gastrointestinal tract and skeletal abnormalities. In familial MTC, only the thyroid is affected. Germ-line mutations of the RET proto-oncogene have recently been reported in association with MEN 2A and familial MTC. All mutations occurred within codons specifying cysteine residues in the transition point between the RET protein extracellular and transmembrane domains. We now show that MEN 2B is also associated with mutation of the RET proto-oncogene. A mutation in codon 664, causing the substitution of a threonine for a methionine in the tyrosine kinase domain of the protein, was found in all nine unrelated MEN 2B patients studied. The same mutation was found in six out of 18 sporadic tumours.

Introduction to distributed algorithms

Abstract: From the Publisher: The second edition of this textbook provides an up-to-date introduction both to the topic, and to the theory behind the algorithms. The clear presentation makes the book suitable for advanced undergraduate or graduate courses, whilst the coverage is sufficiently deep to make it useful for practising engineers and researchers." "The author concentrates on algorithms for the point-to-point message passing model, and includes algorithms for the implementation of computer communication networks. Other key areas discussed are algorithms for the control of distributed applications and fault tolerance achievable by distributed algorithms. The two new chapters on sense of direction and failure detectors are state-of-the-art and will provide an entry to research in these still developing topics.

Homogeneous Catalysts Based on Silane Dendrimers Functionalized with Arylnickel(II) Complexes

Abstract: AT the interface between heterogeneous and homogeneous catalysis there is great scope for the development of new materials that combine the advantages and/or minimize disadvantages associated with each of these classes. In particular there is a need for homogeneous catalysts with properties that allow their ready removal from a product-containing solution. One approach to such materials is to anchor homogeneous catalysts to soluble polymer supports1; we have recently prepared such catalytic materials in which the active centre is an organometallic species2,3. One disadvantage encountered when anchoring catalytic metal sites to polymers is the difficulty of accurate control of the number and location of these sites. Here we report an alternative approach—the synthesis of polysilane dendrimers (highly branched macromolecules4–6) which are functionalized at their periphery with metal-containing catalytically active sites. These dendrimers show regiospecific catalytic activity for the Kharasch addition of polyhalogenoalkanes to carbon–carbon double bonds. It should be possible to remove the nanoscale catalytic macromolecules of this type from the solution of products using filtration methods.

Handbook of Theoretical Computer Science, Vol. B: Formal Models and Semantics

Abstract: From the Publisher: Theoretical computer science provides the foundations for understanding and exploiting the concepts and mechanisms in computing and information processing. This handbook will provide professionals and students with a comprehensive overview of the main results and developments in this rapidly evolving field. It consists of thirty-seven chapters in two volumes, all addressing core areas of theoretical computer science as it is practiced today. The material is written by leading American and European researchers, and each volume may be used independently. Volume A covers models of computation, complexity theory, data structures, and efficient computation in many recognized subdisciplines of theoretical computer science. Volume B presents a choice of material on the theory of automata and rewriting systems, the foundations of modem programming languages, logics for program specification and verification, and several chapters on the theoretic modeling of advanced information processing. The organization of each volume reflects the development of theoretical computer science from its classical roots to the modem theoretical approaches in parallel and distributed computing. Extensive bibliographies, a subject index, and list of contributors are included in each volume.

Recommendations for naming plant pathogenesis-related proteins

Abstract: Pathogenesis-related proteins (abbreviated PRs) are defined as plant proteins that are induced in pathological or related situations. We propose a unifying nomenclature for PRs based on their grouping into families sharing amino acid sequences, serological relationship, and/or enzymatic or biological activity. The nomenclature classifies novel proteins identified by electrophoresis or chromatography along with those established by other workers. The previously proposed system of the five well-established families from tobacco is extended to accommodate a further six families. Families are indicated by arabic numerals and individual members are named by lower case letters in the order in which they are described. Additional rules are proposed to deal with forms containing more than a single polypeptide and as yet unclassified PRs. PR genes whose sequences are conserved but whose designations are not based on function are to be designated Ypr in accordance with the recommendations of the Commission on Plant Gene Nomenclature.

The relative importance of arterial remodeling compared with intimal hyperplasia in lumen renarrowing after balloon angioplasty. A study in the normal rabbit and the hypercholesterolemic Yucatan micropig.

Abstract: BACKGROUND Although arterial renarrowing after angioplasty has been attributed largely to intimal hyperplasia, there has been no systematic effort to correlate the actual hyperplastic tissue mass with angiographic lumen reduction. Using balloon angioplasty in various animal restenosis models, we quantitatively assessed the separate contributions of intimal hyperplasia and arterial remodeling to angiographic late lumen loss. METHODS AND RESULTS Data used for this study were obtained from experiments of conventional and thermal (37 degrees C or 55 degrees to 90 degrees C) balloon angioplasty-treated femoral and iliac arteries in normal rabbits and conventional balloon angioplasty-treated iliac arteries in Yucatan micropigs fed either a normal or an atherogenic diet. Quantitative angiography was performed immediately before and after intervention and at 3 or 8 weeks thereafter, and late loss in lumen diameter was taken as the difference between arterial diameter immediately after treatment and at 3 or 8 weeks of follow-up. Intimal hyperplasia was quantified histologically as the area of tissue mass within the internal elastic lamina. We observed a consistent discrepancy between the actual late loss seen with angiography and the diameter reduction that could be explained by histological intimal thickness alone in both animal models. This discrepancy ranged from 86 +/- 3% of the late loss in the 8 weeks/37 degrees C group to 77 +/- 22% in the conventional group for rabbits and 52 +/- 23% in an atherogenic diet group (n = 10) to 89 +/- 11% in a normal diet group (n = 6) for pigs. This discrepancy appeared to be due predominantly to reduction of the area circumscribed by the internal elastic membrane, a process that is tentatively designated as arterial remodeling. In both the rabbit femoral artery and in the Yucatan iliac artery, remodeling, not intimal hyperplasia, correlated with angiographic late loss. CONCLUSIONS In both the normal rabbit and the normal and atherosclerotic pig, restenosis after angioplasty results from both intimal hyperplasia and arterial remodeling. The exact etiology of arterial renarrowing after angioplasty has important implications on the design of antirestenosis drugs and new coronary devices.

Quantifying Global Warming from the Retreat of Glaciers

Abstract: Records of glacier fluctuations compiled by the World Glacier Monitoring Service can be used to derive an independent estimate of global warming during the last 100 years. Records of different glaciers are made comparable by a two-step scaling procedure: one allowing for differences in glacier geometry, the other for differences in climate sensitivity. The retreat of glaciers during the last 100 years appears to be coherent over the globe. On the basis of modeling of the climate sensitivity of glaciers, the observed glacier retreat can be explained by a linear warming trend of 0.66 kelvin per century.

The toxicokinetics and metabolism of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and their relevance for toxicity.

Abstract: This article reviews the present state of the art regarding the toxicokinetics and metabolism of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). The absorption, body distribution, and metabolism can vary greatly between species and also may depend on the congener and dose. In biota, the 2,3,7,8-substituted PCDDs and PCDFs are almost exclusively retained in all tissue types, preferably liver and fat. This selective tissue retention and bioaccumulation are caused by a reduced rate of biotransformation and subsequent elimination of congeners with chlorine substitution at the 2,3,7, and 8 positions. 2,3,7,8-Substituted PCDDs and PCDFs also have the greatest toxic and biological activity and affinity for the cytosolic arylhydrocarbon (Ah)-receptor protein. The parent compound is the causal agent for Ah-receptor-mediated toxic and biological effects, with metabolism and subsequent elimination of 2,3,7,8- substituted congeners representing a detoxification process. Congener-specific affinity of PCDDs and PCDFs for the Ah-receptor, the genetic events following receptor binding, and toxicokinetics are factors that contribute to the relative in vivo potency of an individual PCDD or PCDF in a given species. Limited human data indicate that marked species differences exist in the toxicokinetics of these compounds. Thus, human risk assessment for PCDDs and PCDFs needs to consider species-, congener-, and dose-specific toxicokinetic data. In addition, exposure to complex mixtures, including PCBs, has the potential to alter the toxicokinetics of individual compounds. These alterations in toxicokinetics may be involved in some of the nonadditive toxic or biological effects that are observed after exposure to mixtures of PCDDs or PCDFs with PCBs.

Cerebral function in diabetes mellitus

Abstract: Diabetes mellitus is a common metabolic disorder associated with chronic complications such as nephropathy, angiopathy, retinopathy and peripheral neuropathy. Diabetes is not often considered to have deleterious effects on the brain. However, long-term diabetes results in a variety of subtle cerebral disorders, which occur more frequently than is commonly believed. Diabetic cerebral disorders have been demonstrated at a neurochemical, electrophysiological, structural and cognitive level; however, the pathogenesis is still not clear. Probably alterations in cerebral blood supply and metabolic derangements play a role, as they do in the pathogenesis of diabetic neuropathy. Furthermore, the brain is also affected by recurrent episodes of hypoglycaemia and poor metabolic control. We describe herein the cerebral manifestations of diabetes and discuss the putative pathogenetic mechanisms.

Phase II Study of Gemcitabine (2′,2′-Difluorodeoxycytidine) in Previously Treated Ovarian Cancer Patients

Abstract: Background Platinum-containing combination chemotherapy has resulted in improved survival rates in patients with advanced ovarian carcinoma, but the majority of the patients still die of their disease. It is therefore important to develop new non-cross-resistant drugs. Gemcitabine (2',2'-difluorodeoxycytidine) has shown a broad spectrum of antineoplastic activity in tumor cell cultures in vitro and in animal tumor models. Clinical activity also has been reported in a variety of solid tumor types. Purpose Our purpose was to assess the clinical activity of gemcitabine in previously treated ovarian cancer patients and to further characterize the toxicity of the compound. Methods Gemcitabine (800 mg/m2) was given intravenously once a week for 3 consecutive weeks, followed by 1 week of rest. A maximum of two different prior treatment regimens was allowed. Response was assessed by pelvic examination and/or ultrasound and computed tomography scans every other course. Results Fifty patients were eligible; 35 (70%) had bulky disease (tumor greater than 5 cm in diameter). All patients had received prior platinum-containing combination chemotherapy. Forty-two patients were assessable for response. Eight (19%) of the 42 patients (95% confidence interval = 9%-34%) achieved a partial response, with a median response duration of 8.1 months (range, 4.4-12.5 months). All responders started treatment with gemcitabine within 6 months of prior treatment, and seven of the eight responders were resistant to first-line platinum-containing combination chemotherapy. Overall median time to progression was 2.8 months (range, 0.2 12.5 months), and overall median survival was 6.2 months (range, 0.2-26.0 months). Forty-eight patients were assessable for toxicity. Leukocytopenia and thrombocytopenia were the main toxic effects that caused dose omissions (27% and 14%, respectively) and dose reductions (37% and 21%, respectively). A transient mild flu-like syndrome occurred in 28% of the patients, and treatment-related peripheral edema developed in 22%. Grade 1 hematuria (53% of patients), grade 1-2 proteinuria (79% of patients), and liver toxicity that was mostly grade 1-2 (59% of patients) were also observed. Conclusions Gemcitabine is a well-tolerated new drug with activity in platinum-resistant ovarian cancer patients. Implications Confirmatory trials are needed, and the activity of gemcitabine in previously untreated patients should be assessed.

Characterization of the budding compartment of mouse hepatitis virus: evidence that transport from the RER to the Golgi complex requires only one vesicular transport step.

Abstract: Mouse hepatitis coronavirus (MHV) buds into pleomorphic membrane structures with features expected of the intermediate compartment between the ER and the Golgi complex. Here, we characterize the MHV budding compartment in more detail in mouse L cells using streptolysin O (SLO) permeabilization which allowed us to better visualize the membrane structures at the ER-Golgi boundary. The MHV budding compartment shares membrane continuities with the rough ER as well as with cisternal elements on one side of the Golgi stack. It also labeled with p58 and rab2, two markers of the intermediate compartment, and with PDI, usually considered to be a marker of the rough ER. The membranes of the budding compartment, as well as the budding virions themselves, but not the rough ER, labeled with the N-acetyl-galactosamine (GalNAc)-specific lectin Helix pomatia. When the SLO-permeabilized cells were treated with guanosine 5'-(3-O-thio)triphosphate (GTP gamma S), the budding compartment accumulated a large number of beta-cop-containing buds and vesicular profiles. Complementary biochemical experiments were carried out to determine whether vesicular transport was required for the newly synthesized M protein, that contains only O-linked oligosaccharides, to acquire first, GalNAc and second, the Golgi modifications galactose and sialic acid. The results from both in vivo studies and from the use of SLO-permeabilized cells showed that, while GalNAc addition occurred under conditions which block vesicular transport, both cytosol and ATP were prerequisites for the M protein oligosaccharides to acquire Golgi modifications. Collectively, our data argue that transport from the rough ER to the Golgi complex requires only one vesicular transport step and that the intermediate compartment is a specialized domain of the endoplasmatic reticulum that extends to the first cisterna on the cis side of the Golgi stack.

GMRESR: a family of nested GMRES methods

Abstract: Recently Eirola and Nevanlinna have proposed an iterativ<: solution method for unsymmetric linear systems, in which the preconditioner is updated from step to step. Following their ideas we suggest variants of GMRES, in which a preconditioner is constructed per it<:ration st<:p by a suitable approximation process, e.g., by GMRES itself. Our numerical experimenb indicate that this may lead to considerable savings in CPU-timc and memory requirements in typical CFD applications.

Deontic logic in computer science: normative system specification

Abstract: Tutorial introduction deontic logic normative system specification legal applications specification of policies.

Coronavirus M proteins accumulate in the Golgi complex beyond the site of virion budding.

Abstract: The prevailing hypothesis is that the intracellular site of budding of coronaviruses is determined by the localization of its membrane protein M (previously called E1). We tested this by analyzing the site of budding of four different coronaviruses in relation to the intracellular localization of their M proteins. Mouse hepatitis virus (MHV) and infectious bronchitis virus (IBV) grown in Sac(-) cells, and feline infectious peritonitis virus (FIPV) and transmissible gastroenteritis virus (TGEV) grown in CrFK cells, all budded exclusively into smooth-walled, tubulovesicular membranes located intermediately between the rough endoplasmic reticulum and Golgi complex, identical to the so-called budding compartment previously identified for MHV. Indirect immunofluorescence staining of the infected cells showed that all four M proteins accumulated in a perinuclear region. Immunogold microscopy localized MHV M and IBV M in the budding compartment; in addition, a dense labeling in the Golgi complex occurred, MHV M predominantly in trans-Golgi cisternae and trans-Golgi reticulum and IBV M mainly in the cis and medial Golgi cisternae. The corresponding M proteins of the four viruses, when independently expressed in a recombinant vaccinia virus system, also accumulated in the perinuclear area. Quantitative pulse-chase analysis of metabolically labeled cells showed that in each case the majority of the M glycoproteins carried oligosaccharide side chains with Golgi-specific modifications within 4 h after synthesis. Immunoelectron microscopy localized recombinant MHV M and IBV M to the same membranes as the respective proteins in coronavirus-infected cells, with the same cis-trans distribution over the Golgi complex. Our results demonstrate that some of the M proteins of the four viruses are transported beyond the budding compartment and are differentially retained by intrinsic retention signals; in addition to M, other viral and/or cellular factors are probably required to determine the site of budding.

Computing minimum length paths of a given homotopy class

Abstract: In this abstract, we use the universal covering space of a surface to generalize previous results on computing paths in a simple polygon. We look at optimizing paths among obstacles in the plane under the Euclidean and link metrics and polygonal convex distance functions. The universal cover is a unifying framework that reveals connections between minimum paths under these three distance functions, as well as yielding simpler linear-time algorithms for shortest path trees and minimum link paths in simple polygons.

Implications of early hominid labyrinthine morphology for evolution of human bipedal locomotion.

Abstract: The upright posture and obligatory bipedalism of modern humans are unique among living primates. The evolutionary history of this behaviour has traditionally been pursued by functional analysis of the postcranial skeleton and the preserved footprint trails of fossil hominids. Here we report a systematic attempt to reconstruct the locomotor behaviour of early hominids by looking at a major component of the mechanism for the unconscious perception of movement, namely by examining the vestibular system of living primates and early hominids. High-resolution computed tomography was used to generate cross-sectional images of the bony labyrinth. Among the fossil hominids the earliest species to demonstrate the modern human morphology is Homo erectus. In contrast, the semicircular canal dimensions in crania from southern Africa attributed to Australopithecus and Paranthropus resemble those of the extant great apes. Among early Homo specimens, the canal dimensions of Stw 53 are unlike those seen in any of the hominids or great apes, whereas those of SK 847 are modern-human-like.

Synthesis and characterization of rigid bidentate nitrogen ligands and some examples of coordination to divalent palladium. X-ray crystal structures of bis(p-tolylimino)acenaphthene and methylchloro[bis(o,o'-diisopropylphenyl-imino)acenaphthene]palladium

Abstract: The synthesis and characterization of the rigid bidentate nitrogen ligands bis-(phenylimino)camphane (Ph-BIC) and a series of bis(arylimino)acenaphthenes (Ar-BIAN) is described. These ligands were synthesized by the reaction of camphorquinone or acenaphthenequinone with the corresponding (substituted) aniline in the presence of ZnCl2 or NiBr2, followed by removal of the metal salt in a subsequent step. NDDO calculations on p Tol-BIAN showed that the electronic properties of this ligand are comparable to the open-chain analogue Ph-DAB (DAB = 1,4-diaza-1,3-butadiene). The aromatic group on the imine N atom of Ar-BIAN ligands is orientated out of the bis(imino)acenaphthene plane, leading to the formation of syn and anti isomers for the ortho-substituted derivatives o-MeC6H4-BIAN and o-i PrC6H4-BIAN. In solution one isomer is observed for these ligands, but upon coordination to a Pd(Me)Cl fragment both syn and anti forms are present, as two isomers are formed. Furthermore, the attempted synthesis of bis(isopropylimino)cyclohexane is described, but it was found that a tautomeric imine-enamine compound is formed which coordinates to palladium(II) in a monodentate fashion, which could not be converted to a chelating ligand. The structures of p Tol-BIAN and Pd(Me)Cl(o,o′-i Pr2C6H3-BIAN) in the solid state were determined by X-ray diffraction. p Tol-BIAN is monoclinic, space group C2, a = 20.021(2), b = 8.7703(10), c = 5.5664(10) A, β = 103.37(1)°, Z = 2, final R = 0.040 for 963 reflections with I > 2.5σ(I). Pd(Me)Cl(o,o′-i Pr2C6H3-BIAN) is orthorhombic, space group Pbca, a = 11.440(2), b = 21.250(3), c = 27.087(2) A, Z = 8, final R = 0.043 for 2433 reflections with I > 2.0σ(I >).

Estimate of the wavelength dependency of ultraviolet carcinogenesis in humans and its relevance to the risk assessment of a stratospheric ozone depletion.

Abstract: The wavelength dependency of carcinogenesis is an important factor in risk assessments pertaining to sources of ultraviolet radiation, the most important of which is the sun. This wavelength dependency cannot be measured directly in humans, but it has been measured in hairless mice, and represented in an action spectrum. An estimate of the action spectrum for humans can be produced by correcting for differences in epidermal transmission between mice and humans. This carcinogenic action spectrum for humans resembles the action spectrum for ultraviolet-induced erythema (sunburn), and results in small adjustments of earlier estimates of the effects of a stratospheric ozone depletion on skin cancer incidences.

Concentrations of serum amyloid-A (SAA) and haptoglobin (HP) as parameters of inflammatory diseases in cattle

Abstract: The concentrations of the acute-phase proteins, serum amyloid-A (SAA) and haptoglobin (Hp), were determined in the plasma of healthy cows (n = 25) and cows with spontaneous acute (n = 6), subacute (n = 37), or chronic (n = 7) inflammatory diseases. The plasma concentration of SAA alone, Hp alone, and the Hp/SAA ratio, differed significantly (p < 0.001) between healthy animals and animals with inflammatory diseases. Plasma Hp concentrations in the group of cows with acute inflammatory diseases were significantly (p < 0.01) different from those in the group with chronic inflammatory diseases. Moreover, the Hp/SAA ratio in chronic inflammatory diseases was significantly different from this ratio in acute (p < 0.01) and subacute (p < 0.05) inflammatory diseases. It is therefore concluded that the plasma concentrations of SAA and Hp and the Hp/SAA ratio are useful parameters to distinguish healthy animals from animals with inflammation and can be helpful in distinguishing between acute and chronic of inflammatory diseases.

Why Groups are less Effective than their Members: On Productivity Losses in Idea-generating Groups

Abstract: There is pervasive evidence that people produce more ideas and more good ideas when working alone rather than in groups. This chapter will first review the evidence for the productivity loss in brainstorming groups and then evaluate the various theoretical explanations which have been offered to account for these findings in the light of empirical research. This evidence suggests that the productivity loss in idea-generating groups is caused mainly by mutual production blocking due to the constraint on groups that members can talk only in turn. We then discuss various strategies that have been developed to overcome the disruptive effects of production blocking. However, since so far even the most successful strategies have raised the productivity of group members only to the level they would have achieved if they had worked individually, our final section discusses an ‘illusion of group effectivity’ as a reason for the persistence of the belief that group discussions are an effective means of generating i...

A flume study on the development and equilibrium morphology of current ripples in very fine sand

Abstract: An empirical model is constructed for the development and equilibrium dimensions of small scale, unidirectional bedforms in sand with a median grain size of 0·095 mm, based on a series of steady flow experiments in a flume. Current ripples always attain a linguoid plan morphology with constant average height (13·1 mm) and wavelength (115·7 mm), provided that sufficient time is allowed for their formation. The development pattern of these ripples on a flat bed is independent of flow velocity, and involves four stages: (1) incipient ripples; (2) straight and sinuous ripples; (3) non-equilibrium linguoid ripples, and (4) equilibrium linguoid ripples. Straight and sinuous ripples are non-equilibrium bedforms at all flow velocities. The time needed to reach equilibrium dimensions is related to the inverse power of flow velocity and ranges from several minutes to more than hundreds of hours. At flow velocities where washed ripples are stable, the equilibrium wavelength is similar to that of equilibrium linguoid ripples, but the equilibrium height rapidly decreases from 13·1 mm to zero towards upper stage plane bed conditions. The results of the flume experiments correspond reasonably well with those of previous studies, provided that various complicating factors, such as different experimental methods, different sediment characteristics, shallow flow depths and non-equilibrium runs, are accounted for.

Prognostic factors for treatment of malignant lymphoma in dogs.

Abstract: Pretreatment characteristics of 138 dogs with malignant lymphoma were analyzed to determine prognostic factors associated with outcome (ie, complete response rate, time to relapse after complete response, survival time). Dogs were all treated for 10 weeks, using a standard induction chemotherapy protocol, and were then given asparaginase weekly. Once the disease became progressive, second-line chemotherapy was instituted. Age, sex, weight, clinical stage, performance grade, immunophenotype, and malignancy grade assigned according to the National Cancer Institute's Working Formulation were not associated with complete response rate. However, malignancy grade assigned according to the Kiel classification was found to be associated with complete response rate; dogs with high-grade malignancies had a significantly higher complete response rate than did dogs with low-grade malignancies. By means of multivariate analysis, clinical stage and immunophenotype were found to be prognostic factors for time to relapse (among dogs that had had a complete response) and survival time. In addition, malignancy grade assigned according to the Kiel classification was found to be a prognostic factor for time to relapse; whereas, malignancy grade assigned according to the Working Formulation was determined to be a prognostic factor for survival time.

Male Bonds: Afilliative Relationships Among Nonhuman Primate Males

Abstract: A deductively obtained model concerning the factors that determine male social relationships within the framework of primate social organization is discussed in the light of existing empirical evidence. Tolerance and affiliative bonding are expected to occur less easily between male than between female primates. Whereas females compete for resources such as food, males, in addition compete to obtain fertilizations. Unlike food, fertilizations cannot easily be shared. This undoubtedly hampers the formation of male coalitions and the development of male bonds. Indeed, male tolerance tends to be low especially in species where the spatial and temporal distribution of females is such that individual males may monopolize access to such females, thus facilitating inter-male contest. Nevertheless there are a number of species in which tolerance between adult male group members is remarkable. In some cases forms of coordination and mutual attraction exist that justify the qualification of 'male bonding'. An important factor supposed to conduce to the development of male bonding is the inclusive fitness benefit that support and tolerance between male relatives may bring. This would occur especially where circumstances permit male philopatry. The latter is expected in species where the nature of female competition for basic resources does not lead to strong female-bondedness and female nepotism, allowing females to become allopatric. There is evidence from various species that related males form bonds under the mentioned conditions. A special case of this is the formation of father-son bonds, noted in species with strong intermale contest and corresponding sexual dimorphism. A remarkable alternative, by the way, is the existence of mother-son bonds which last into adulthood and which contribute to a male's position. There are indications for such bonds in two species where males stay with their mother and where sexual dimorphism is low. Still kinship clearly is not a necessary factor for the development of male tolerance and of support between males. The factor does not play a role, for instance, in the short-term coalitions found in baboons. Here opportunism based on mutual or reciprocal benefits seems to play a decisive role. The evidence presented lends support to the idea that there is an order of priorities, in which, first, socioecological factors determine the spatial, hierarchical and affiliative relationships between females. These female relationships then set the scene for the males, in that these determine the options left open for the males to organize their patterns of competition, migration and bonding.