bluuebunny/crossref_metadata_2025 huggingface dataset:
B chromosomes in Crustacea Decapoda
Authors: Coluccia E. , Cannas R. , Cau A. , Deiana A.M. , Salvadori S.
Published: August 2004

Among crustacean Decapoda numerical chromosome variability is frequent, and it has been hypothesized that the presence of supernumerary chromosomes accounts for this variability. Thanks to the improvement of cytogenetic analysis by chromosomal banding techniques, supernumerary B chromosomes (Bs) have been demonstrated in Nephrops norvegicus, Homarus americanus,Palinurus elephas and P. mauritanicus, belonging to different crustacean families. In all four species Bs were variable in number, mainly heterochromatic and undigested by various endonucleases, and in meiosis they showed non-Mendelian segregation. Compared to the other chromosomes of the complement, the Bs are very small in almost all species, but some of them were very large in N. norvegicus.
Current knowledge on B chromosomes in natural populations of helminth parasites: a review
Authors: Špakulová M. , Casanova J.C.
Published: August 2004

Helminths, traditionally classified into three phyla Platyhelminthes, Nemathelminthes and Acanthocephala, are a phylogenetically broadly diversified group of invertebrates, characterised by a parasitic life style. Current estimates of the helminth species diversity are at least 23–40,000 platyhelminthes, 10–26,000 nematodes and 1,200 acanthocephalans. Recent information on helminth karyotypes is fragmentary, and basic karyological data are known from approximately 1.1% of known species. Supernumerary chromosomes have been reported in selected populations of only 11 digenean flukes (Platyhelminthes), 1 thorny-headed worm (Acanthocephala) and 4 roundworms (Nematoda), which represent 3.6, 7.7 and 1.3% of the total number of species cytogenetically analysed to date within respective helminth groups. B chromosome presence was not generally associated with heteromorphic sex chromosomes as they occurred both in hermaphroditic flukes and dioecious helminths, and in species having male or female heterogametic sex chromosomes (ZW of schistosomes, XO of acanthocephalans and XY of nematodes). Numbers of B chromosomes varied from 1 to 10. Most often, Bs represented one or two of the smallest elements of the complement but they could be much bigger in some digenean flukes. B chromosomes showed a diverse morphology, including telocentric to metacentric structure. There is no detailed banding or ultrastructural study of Bs in the majority of helminth carriers. Assumptions on the possible relation between the occurrence of Bs in endoparasitic helminths and extreme environments are discussed.
B chromosomes in the fish Astyanax scabripinnis (Characidae, Tetragonopterinae): An overview in natural populations
Authors: Moreira-Filho O. , Galetti Jr. P.M. , Bertollo L.A.C.
Published: August 2004

Astyanax scabripinnis, a small neotropical freshwater fish, is a headwater species living in small tributaries of many Brazilian rivers, where they form isolated populations. This species harbors a B chromosome system in several populations. Among the several kinds of Bs reported in this species, the BM variant, a large metacentric of a similar size to the largest A chromosome, is the most widespread in natural populations. It probably corresponds to the ancestral B type in this species and a very similar B chromosome is also found in other Astyanax species. Strong evidence suggests that this B is an isochromosome showing structural and functional homology between its two arms, as shown by satellite DNA localization and the formation of a ring B univalent during meiosis. The BSM and Bm variants, a large submetacentric and a small metacentric, respectively, represent rare variants and may be derived from structural rearrangements of the BM chromosome. In addition, B microchromosomes (Bmicro) were found in some populations. Frequency analyses in mountain populations have shown that B chromosomes are found in populations located at high altitude, but are absent in populations at low altitude, which is consistent with their parasitic nature, given the ecological peculiarities of both kinds of populations.
Structure and evolution of B chromosomes in amphibians
Authors: Green D.M.
Published: August 2004

B chromosomes are known from 26 species of salamanders and frogs, equivalent to about 2% of amphibian species that have been karyotyped. In most cases, the structure of amphibian B chromosomes has not been extensively investigated. The exceptions are the B chromosomes of Hochstetter’s frog, Leiopelma hochstetteri, from New Zealand, and the Coastal Giant salamander, Dicamptodon tenebrosus, from North America. Dicamptodon tenebrosus carries from 0 to 10 non-heterochromatic, telocentric B chromosomes per individual, averaging 0 to 3.4 B chromosomes per individual in populations throughout its extensive range. The B chromosomes of L. hochstetteri occur in frequencies averaging from 0 to 11.4 per individual in different populations, with a known maximum of 15 B chromosomes. Amphibian B chromosomes vary in size, heterochromatin, occurrence and frequency. They are commensurate in size and structure with the rest of the A set of chromosomes of the same species in which they occur. The B chromosomes are at least partly composed of repetitive DNA sequences which exist in numerous copies throughout the autosomes, in conformity to an hypothesis of intraspecific B chromosome origins.
Occurrence of B chromosomes in lizards: a review
Authors: Bertolotto C.E.V. , Pellegrino K.C.M. , Yonenaga-Yassuda Y.
Published: August 2004

Although B chromosomes have been reported in many species of plants and animals, few studies have revealed the presence of these extra chromosomes in lizards. B chromosomes of lizards show different morphologies and sizes, from microchromosomes to macrochromosomes, or elements of intermediate size between smaller and larger A chromosomes, and number variability at intra- and inter-individual levels. In most cases, they are late-replicating and show either heterochromatic or no distinctive patterns after C-banding. The great majority of the publications about supernumerary chromosomes in this group have been based on conventional staining analyses, and there is no study designed to address questions related to their composition and structure or origin and evolution.
B chromosomes in populations of mammals
Authors: Vujošević M. , Blagojević J.
Published: August 2004

B chromosomes (Bs) have been found in 55 out of 4629 living species of mammals. The summarized data show great variability in types of mammalian Bs, including differences in size, shape and molecular composition. This variability extends to the origin, mode of transmission and population dynamics. In general, B chromosomes in mammals do not differ from Bs found in other animal or plant species, but some peculiarities do exist. Most species in which Bs are found are widespread. Some data support the view that Bs may contribute to the successful expansion of some of these species, but it is possible that Bs are just more easily scored in them due to their frequent occurrence. Most of these species are also characterized by cycling fluctuations of abundance and characteristic social organization that produce conditions favorable for Bs to spread. All areas of research on Bs in mammals suffer from lack of data, emphasizing the necessity for intensified research on the molecular structure and ways of maintenance of Bs in populations.
B chromosomes in Brazilian rodents
Authors: Silva M.J.J. , Yonenaga-Yassuda Y.
Published: August 2004

B chromosomes are now known in eight Brazilian rodent species: Akodon montensis, Holochilus brasiliensis, Nectomys rattus, N. squamipes, Oligoryzomys flavescens, Oryzomys angouya, Proechimys sp. 2 and Trinomys iheringi. Typically these chromosomes are heterogeneous relative to size, morphology, banding patterns, presence/absence of NORs, and presence/absence of interstitial telomeric signals after FISH. In most cases, Bs are heterochromatic and late replicating. Active NORs were detected in two species: Akodon montensis and Oryzomys angouya. As a rule, Bs behave as uni or bivalents in meiosis, there is no pairing between Bs and autosomes or sex chromosomes and also their synaptonemal complexes are isopycnotic with those in A chromosomes.
The mammalian model for population studies of B chromosomes: the wood mouse (Apodemus)
Authors: Wójcik J.M. , Wójcik A.M. , Macholán M. , Piálek J. , Zima J.
Published: August 2004

The presence of B chromosomes was reported in six species of the genus Apodemus (A. peninsulae, A. agrarius, A. sylvaticus, A. flavicollis, A. mystacinus, A. argenteus). High frequencies of Bs were recorded particularly in A. peninsulae and A. flavicollis. The origin of Bs in Apodemus seems to be rather ancient, and it is possible that the supernumerary elements, and/or a tendency for their appearance, were inherited from the common ancestor of the extant species. We have not found any correlated changes between frequencies of Bs and the level of protein polymorphism and/or heterozygosity assessed in electrophoretic studies. No measurable effect of Bs on overall genetic variability was thus revealed in studied populations. The pattern of evolutionary dynamics of Bs can be distinctly different between geographical populations, and both the parasitic and the heterotic models can be applied to explain the maintenance of Bs in different populations. Further studies are desirable to improve our understanding of the complicated evolutionary dynamics of Bs in the Apodemus species. An essential condition for success in this respect is much more detailed information on inheritance and the molecular structure of Bs.
A complex B chromosome system in the Korean field mouse, Apodemus peninsulae
Authors: Kartavtseva I.V. , Roslik G.V.
Published: August 2004

Information on B chromosomes of six subspecies of A. peninsulae Thomas, 1906, from 79 local populations of Russia (Siberia, Altai, Buryatia and the Far East), Mongolia, China, Korea and Japan (Hokkaido) is reviewed. The frequency of animals with B chromosomes is higher in this taxon than in other mammals and ranges from 0.4 up to 1.0, excluding two insular populations (Sakhalin Island and Stenin Island, Primorye) where Bs were not found. The B chromosome polymorphism shows four levels of variation in number (intraindividual mosaicism, intrapopulational and interpopulational), as well as variability in size, morphology and differential staining. Geographic variation was found among populations for these cytogenetic characteristics and, in some cases, it coincided with subspecies distribution. Comparative chromosome banding of micro and macro Bs illuminates possible pathways for their origin.
A RAPD marker associated with B chromosomes in Partamona helleri (Hymenoptera, Apidae)
Authors: Tosta V.C. , Fernandes-Salomão T.M. , Tavares M.G. , Pompolo S.G. , Barros E.G. , Campos L.A.O.
Published: August 2004

The hymenopteran Partamona helleri is found in southwestern Brazil in the Mata Atlântica from the north of the state of Santa Catarina until the south of Bahia. This work shows that P. helleri can carry up to four B chromosomes per individual. In order to obtain more information about P. helleri B chromosomes, the RAPD technique was used to detect DNA fragments associated with these chromosomes. The results showed that the RAPD technique is useful to detect specific sequences associated with B chromosomes. One RAPD marker was identified, cloned and used as probe in a DNA blot analysis. This RAPD marker hybridized with sequences present only in individuals containing B chromosomes.
Comparative analysis of micro and macro B chromosomes in the Korean field mouse Apodemus peninsulae (Rodentia, Murinae) performed by chromosome microdissection and FISH
Authors: Rubtsov N.B. , Karamysheva T.V. , Andreenkova O.V. , Bochkaerev M.N. , Kartavtseva I.V. , Roslik G.V. , Borissov Y.M.
Published: August 2004

Comparative analysis of micro B and macro B chromosomes of the Korean field mouse Apodemus peninsulae, collected in populations from Siberia and the Russian Far East, was performed with Giemsa, DAPI, Ag-NOR staining and chromosome painting with whole and partial chromosome probes generated by microdissection and DOP-PCR. DNA composition of micro B chromosomes was different from that of macro B chromosomes. All analyzed micro B chromosomes contained clusters of DNA repeats associated with regions characterized by an uncondensed state in mitosis. Giemsa and DAPI staining did not reveal these regions. Their presence in micro B chromosomes led to their special morphology and underestimation in size. DNA repeat clusters homologous to DNA of micro B chromosome arms were also revealed in telomeric regions of some macro B chromosomes of specimens captured in Siberian regions. Neither active NORs nor clusters of ribosomal DNA were found in the uncondensed regions of micro B chromosomes. Possible evolutionary pathways for the origin of macro and micro B chromosomes are discussed.
FISH detection of ribosomal cistrons and assortment-distortion for X and B chromosomes in Dichroplus pratensis (Acrididae)
Authors: Bidau C.J. , Rosato M. , Martí D.A.
Published: August 2004

Assortment-distortion with respect to the X and NOR activity of a rare mitotically stable B chromosome (BN), was examined in 16 males of Dichroplus pratensis (Acrididae: Melanoplinae) from Argentine populations. In 1B individuals, the X and B associate preferentially during prophase I reaching a maximum level of association at zygotene. Frequency of X/B association remains relatively high up to diplotene-diakinesis and decreases steeply towards metaphase I. The percent X/B association at each stage is positively influenced by association at the previous stage, and interindividual variability in X/B association decreases as the frequency of association increases. Both chromosomes tended to preferentially orientate toward the same pole at MI (mean ratio of 16 individuals, 1.50:1) which determined an excess of XB and 00 second spermatocytes over X0 and 0B ones (1.39:1). No significant differences occurred between the MI, AI and MII assortment ratios. Fluorescent in situ hybridisation (FISH) confirmed that the B chromosome carries ribosomal genes and helped to establish that, during spermiogenesis, both the B and the normal NOR-bearing chromosome (S8) are clustered near the centriole adjunct region of spermatids. However, FISH failed to reveal the existence of inactive ribosomal cistrons in the X chromosome, as previously suggested, thus providing no support to a simple origin of the B from the X.
X and B chromosomes display similar meiotic characteristics in male grasshoppers
Authors: Viera A. , Calvente A. , Page J. , Parra M.T. , Gómez R. , Suja J.A. , Rufas J.S. , Santos J.L.
Published: August 2004

We have analysed the chromosome organisation and the location and temporal appearance of different proteins in X and B chromosomes in the grasshopper Eyprepocnemis plorans throughout the first meiotic prophase. We have used adult males that carry a B chromosome collected in natural Spanish populations. The scaffold organisation has been analysed by means of silver stained chromatid cores. In addition, we have detected by immunolabelling the presence of phosphoepitopes, the ensemble of cohesin axes, the location of histone γ-H2AX, and recombinase Rad51. Our observations demonstrate that X and B chromosomes share similarities in chromatin organisation and in the expression of the tested proteins, which strongly differ from those of the autosomes. These results could be interpreted either as a support to the hypothesis that the Bs analysed here originated from the X chromosome, and/or that their chromatin composition and precocious condensation could determine their meiotic behaviour.
An asymptotic determination of minimum centromere size for the maize B chromosome
Authors: Phelps-Durr T.L. , Birchler J.A.
Published: August 2004

The maize B chromosome is a dispensable chromosome and therefore serves as a model system to study centromere function. The B centromere region is estimated to be approximately 9,000 kb in size and contains a 1.4 kb repeat that is specific to this centromere. When maintained as a univalent, the B chromosome occasionally undergoes centric misdivision. Consecutive misdivision analysis of the maize B chromosome centromere has generated a collection of functional centromeres that are greatly reduced in complexity. These small centromeres are often correlated with strongly reduced meiotic transmission. Molecular analyses of the misdivision collection have revealed that the smallest functional maize B centromere is a minimum of 110 kb in size. Considering the collection as a whole, meiotic transmission becomes severely compromised when the estimated centromere size is reduced to a few hundred kilobases.
B chromosomes in hybrids of temperate cereals and grasses
Authors: Jenkins G. , Jones R.N.
Published: August 2004

B chromosomes are considered to be genetically inert, yet often have pronounced and surprising effects upon the A chromosome behaviour at meiosis in inter-generic and inter-specific hybrids. We review here our current knowledge of these effects in a number of different hybrids of the temperate cereals and grasses. Through hybridisation, many effects comparable to the pairing control system of wheat are uncovered, together with complex interactions of B chromosomes with hybrid host genotypes. We discuss the genetic and physical basis of the effects and try to make sense of them in terms of what we know about the origin and evolution of B chromosomes in plants.
The odd-even effect in mitotically unstable B chromosomes in grasshoppers
Authors: Camacho J.P.M. , Perfectti F. , Teruel M. , López-León M.D. , Cabrero J.
Published: August 2004

The odd-even effect, by which B chromosomes are more detrimental in odd numbers, has been reported in plants and animals. In grasshoppers, there are only a few reports of this effect and all were referred to as traits related to the formation of aberrant meiotic products (AMPs). Here we review the existing information about B chromosome effects on AMPs, chiasma frequency and the number of active nucleolus organizer regions (NORs) per cell. Polysomy for A chromosomes and B chromosomes are two kinds of chromosome polymorphism frequently found in grasshoppers. In some aspects, e.g. meiotic behaviour and mitotic instability leading to individual mosaicism (in the case of mitotically unstable Bs), polysomic As show similar characteristics to B chromosomes. In fact, polysomy is regarded as one of the main mechanisms for B chromosome origin. Here we review some features of meiotic behaviour in known cases of polysomy and mitotically unstable Bs in grasshoppers, in looking for possible causes for the odd-even effect. In all these traits, the odd-even effect was apparent, although its appearance was not universal in any case, with variation among species or populations within the same species. The equational division and lagging of the extra chromosomes, when univalents, could favour the appearance of abnormal meiotic products, and the formation of bivalents, when there are two or more extra chromosomes, inhibits this process. Therefore, the odd-even effect might be a consequence of the concomitant operation of both aspects of extra chromosome meiotic behaviour. The possibility that the odd-even effect might result from an increase in cell stress generated by odd numbers is suggested.
Rapid suppression of drive for a parasitic B chromosome
Authors: Perfectti F. , Corral J.M. , Mesa J.A. , Cabrero J. , Bakkali M. , López-León M.D. , Camacho J.P.M.
Published: August 2004

The persistence of parasitic B chromosomes in natural populations depends on both B ability to drive and host response to counteracting it. In the grasshopper Eyprepocnemis plorans, the B24 chromosome is the most widespread B chromosome variant in the Torrox area (Málaga, Spain). Its evolutionary success, replacing its ancestral neutralized B variant, B2, was based on meiotic drive in females, as we showed in a sample caught in 1992. In females collected six years later, mean B24 transmission ratio (kB) was 0.523, implying a very rapid decrease from the 0.696 observed in 1992. This shows that B24 neutralization is running very fast and suggests that it might most likely be based on a single gene of major effect.
Transmission analysis of B chromosomes in Rattus rattus from Northern Africa
Authors: Stitou S. , Zurita F. , Díaz de la Guardia R. , Jiménez R. , Burgos M.
Published: August 2004

Traditionally, B chromosomes have been classified as parasitic or heterotic, depending of whether or not they show selfish behaviour. Nevertheless, experimental evidence has been found supporting the idea that supernumerary chromosomes may evolve from parasitism to neutrality. In this work, B chromosome transmission in Rattus rattus has been analysed by performing several crosses between individuals carrying different numbers of supernumerary chromosomes. Our results demonstrated a Mendelian transmission rate through males, but slight accumulation of the Bs through females. This parasitic behaviour is shared in populations as distant as Asia and Africa, and even in a related species in Australia, suggesting the possibility of an ancient origin of these supernumerary chromosomes.
Cytogeography and the evolutionary significance of B chromosomes in relation to inverted rearrangements in a grasshopper species
Authors: Colombo P. , Confalonieri V.
Published: August 2004

The analysis of geographic distribution of polymorphic cytological markers, briefly termed as cytogeography, can be considered an important tool to be applied when studying the evolutionary significance of chromosome variability within a species, either to unravel the adaptive significance of chromosome polymorphisms or to investigate the parasitic nature of some genomic elements. In this article we review cytogeographical studies in Trimerotropis pallidipennis, a grasshopper species whose South American populations display geographical patterns of distribution of inversion and B chromosome polymorphisms. Several lines of evidence that issue from the analysis of the geographic distribution of polymorphic markers suggest that inverted chromosomes are special sequences that are maintained by deterministic forces. On the other hand, the pattern of distribution of B chromosome polymorphism clearly demonstrates its selfish nature, being more frequent in those populations in central environments. We also present the analysis of 272 individuals of T. pallidipennis from Uspallata, and demonstrate that Bs in this population have some influence on body size, enlarging many of the morphometric characters of individuals and we propose it could be the consequence of its genotypic disequilibrium with one inversion. These investigations are finally discussed with regard to the models proposed for the maintenance of B chromosomes in natural populations and in relation to the possible interactions with chromosome inversions.
Mitotically unstable B chromosome polymorphism in the grasshopper Dichroplus elongatus
Authors: Remis M.I. , Vilardi J.C.
Published: August 2004

Dichroplus elongatus, a widespread South American phytophagous grasshopper, exhibits polymorphisms for supernumerary chromosomes and segments (SS) in natural populations in Argentina. In this paper we review the available information on B chromosome polymorphism in D. elongatus related to geographic distribution, patterns of chromosome variation and influence on sperm formation. In D. elongatus the different forms of supernumerary variants are not independent. The proportion of B-carrying individuals (B prevalence) is negatively correlated with SS10 and positively with SS6 frequencies. The analysis of population structure considering the different supernumerary variants would suggest that the patterns of chromosome variation can not be explained only by random factors. Geographic distribution was analyzed scoring the prevalence of B chromosomes in 13 natural populations collected in three different biogeographical provinces from Northwest (Las Yungas province) and East (Espinal and Pampeana provinces) of Argentina. The detected heterogeneity may be explained by significant differentiation between Northwest and East regions and among populations within Las Yungas and Pampeana provinces. Correlation analysis suggested that B chromosome prevalence is associated with maximum temperature and with latitude. Additional information about the nature of the patterns of B chromosome variation was obtained comparing them with those obtained at the mitochondrial DNA level. The hierarchical analysis of molecular differentiation revealed discrepancy with respect to chromosome differentiation and also suggested that the pattern of B chromosomes may not be explained by historical factors. We also discussed the probable influence on fertility of carriers considering the production of abnormal sperm formation (macro and microspermatids) in relation to the number of Bs per follicle.
Geographic and seasonal variations of the number of B chromosomes and external morphology in Psathyropus tenuipes (Arachnida: Opiliones)
Authors: Tsurusaki N. , Shimada T.
Published: August 2004

Psathyropus tenuipes (= Metagagrella tenuipes) is a harvestman that harbors B chromosomes with extremely high frequency (individuals without Bs are only 1% of the total number of specimens so far examined) and high numbers (mean number of Bs per individual is about 4). Geographic variations of the number of Bs and external morphology of the species and the relationship between them were studied. A northward increase in the number of Bs was detected throughout the Japanese Islands, though the number also varied considerably locally. Latitudinal gradients were also found in some external characters, while there were no correlations between those external morphologies and the number of Bs. Principal component analysis using eight morphological data for 21 populations revealed four geographical groups that reflect actual location of the populations. Populations along the Seto Inland Sea were characterized by a lower number of Bs than those in other areas. Seasonal change was also found in a population (Yatsukami in western Honshu) in both 1994 and 1995 for the number of Bs, though the number in the same population was stable at least throughout later postembryonic stages in both 1997 and 1998. Embryos contained fewer numbers of Bs than adults, suggesting that females of the species tend to lay eggs with fewer numbers of Bs.
Imitate to integrate: Reviewing the pathway for B chromosome integration in Trypoxylon (Trypargilum) albitarse (Hymenoptera, Sphecidae)
Authors: Rocha-Sanchez S.M.S. , Pompolo S.G.
Published: August 2004

B chromosomes are genomic “intruders” normally characterized by their total dispensability counteracted by a variety of drive mechanisms, which assures their presence regardless of their harmful effects on the host genome. From an evolutionary standpoint, the relationship between standard (A) and B chromosomes can go through different pathways, from an everlasting arms race to a cordial B integration. Examples underlying the first situation are fairly common; B integration, however, has been more a theoretical than a practical possibility. The B chromosome in the haplodiploid solitary wasp Trypoxylon albitarse is probably the first example of a “mimetic” B, which is being integrated into the A genome by limiting itself to one B per haploid genome, the same dosage as the A chromosomes. Here we review some of the findings underlying this hypothesis and discuss the T. albitarse B strategy as a possible mechanism for B chromosome integration as a regular member of the chromosome complement in haplodiploid organisms.
B chromosomes: the troubles of integration
Authors: Granado N. , Rebollo E. , Sánchez F.J. , Arana P.
Published: August 2004

Starting with a spontaneous B-A centric fusion found in a natural population of the grasshopper Eyprepocnemis plorans, we have obtained different strains carrying the rearrangement in various conditions and doses. Using this material, we have analyzed the meiotic behavior of the translocated chromosome in living cultured spermatocytes, simulating the successive steps of a hypothetical process of integration of a B chromosome into the standard genome via B-A centric fusion. Remarkably, the behavior of fusion heterozygotes, the initial step of the integration process, is much more regular than that of any other configuration, including homozygotes. The reasons for the failure of B chromosome integration into the normal complement by translocation are discussed.
The Childhood Component of the ICP Model Is Appropriate for Growth Analysis of Short Israeli Children
Authors: Limony Y. , Leiberman E. , Hershkovitz E.
Published: August 2004

Objective: To determine whether the childhood component of the infancy-childhood-puberty (ICP) model is appropriate for growth analysis of short Israeli children. Subjects and Methods: From 204 short, prepubertal children, 2–16 years of age, 1,516 height measurements were analyzed. For each child’s measurements, a best-fitted line based on C equation of ICP has been drawn and the distribution of measurement points around that line was calculated. Results: Ninety percent of the measurements were at a distance of no more than ±2 cm from the best-fitted ICP line. Conclusion: The C component of ICP model can be used as a growth analysis tool for shorter than average, prepubertal, Israeli children, older than 2 years of age.
Lost and Found Testes: The Importance of the hCG Stimulation Test and Other Testicular Markers to Confirm a Surgical Declaration of Anorchia
Authors: McEachern Rebecca , Houle Anne-Marie , Garel Laurent , van Vliet Guy
Published: August 2004

Background: In patients with impalpable testes,laparoscopy or open surgery is considered conclusive in establishing the absence of testicular tissue. Methods: Retrospective chart review. Results: Over a 22-year period, 4 out of 82 patients with a diagnosis of bilateral anorchia by laparoscopy or laparotomy had persistent testicular tissue suggested by endocrine evaluations. The clue to the presence of testicular tissue was: (1) a pubertal rise in plasma testosterone (2 patients); (2) the presence of possible Müllerian structures and of a detectable plasma anti-Müllerian hormone (1 patient), and (3) the fact that one of the gonads had not been seen at surgery (1 patient who still had a testosterone response to hCG postoperatively). Testes were localized by venography (3 patients) and laparotomy (1 patient). Conclusion: A surgical diagnosis of bilateral anorchia needs to be confirmed by hCG stimulation, gonadotropin levels, or other markers of testicular function.
Expression of Leptin Receptor Isoforms and Effects of Leptin on the Proliferation and Hormonal Secretion in Human Pituitary Adenomas
Authors: Kristiansen M.T. , Clausen L.R. , Nielsen S. , Blaabjerg O. , Ledet T. , Rasmussen L.M. , Jørgensen J.O.L.
Published: August 2004

Objective: To pursue whether leptin regulates anterior pituitary cells, we studied the ex vivo expression of several isoforms of the leptin receptor (OB-R) as well as the in vitro effects of leptin administration in human pituitary adenomas. Methods: OB-R mRNA expression and in vitro response to leptin were studied in 39 pituitary macroadenomas. Results: All 4 OB-R subtypes were expressed in most adenomas. The expression was significantly more pronounced in GH-secreting adenomas as compared to non-functioning tumor cells (p < 0.05). Leptin administration in vitro did not significantly influence cell proliferation or the secretion of GH, FSH, LH or α-subunit. Conclusions: (1) Several isoforms of the OB-R, including the signal transducing full-length receptor, are expressed in most human pituitary adenomas. (2) This expression ex vivo is not associated with significant effects of leptin in vitro.
Changes of the Cardiac Architectures and Functions for Chronic Hemodialysis Patients with Dry Weight Determined by Echocardiography
Authors: Chang Shih-Tai , Chen Chien-Chung , Chen Chan-Long , Cheng Hui-Wen , Chung Chang-Min , Yang Teng-Yao
Published: August 2004

Background/Aims: Left ventricular hypertrophy (LVH) has long been known as an independent risk factor for cardiovascular deaths, in both dialysis and general populations. Numerous factors influence the pathophysiology of LVH. However, extracellular fluid may have a particularly important influence on this impact. Inferior vena cava diameter (IVCD) estimation is a non-invasive and relatively convenient method for obtaining a good correlation with the intravascular fluid status, and may obtain an optimal dry weight (DW) for chronic hemodialysis patients. This study estimates the DW of end-stage renal disease (ESRD) patients by echocardiographic measurement of the IVCD to observe changes in cardiac morphology and function. Methods: A total of 88 patients, ranging from 26 to 90 (59.4 ± 13.3) years of age, were involved in this study. The patients were divided into study (n = 48) and control (n = 40) groups. All patients received IVCD assessment via echocardiography bi- monthly for 1 year. In the study group patients, DW was adjusted according to the IVCD by echocardiography. Meanwhile, in the control group patients, DW was adjusted based on traditional clinical parameters. All patients underwent cardiac examinations and measurements, including left ventricular mass (LVM), wall thickness, chamber size and left ventricular systolic function by echocardiography, at the beginning and end of the study. Results: Both groups displayed comparable clinical and biochemical parameters. The IVCD index correlated well with the cardiac parameters estimated by echocardiography. The LVM and left ventricular mass index (LVMI) was reduced significantly in the study group patients (from 200 ± 64.2 to 187 ± 63.2 g, p = 0.021; from 132 ± 37.6 to 123 ± 37.3 g/m2, p = 0.014, respectively). Furthermore, the study group patients with fluid overload, named study subgroup A, displayed significant differences not only in LVM and LVMI, but also in septal wall thickness, left ventricular end-diastolic dimension and left atrial dimension. In contrast, the control group displayed no changes in these cardiac architectures during the study period. Conclusion: Adjusting DW via the IVCD measured by echocardiography for hemodialysis patients may prevent the progression of chamber dilatation and LVH, especially for patients with fluid overload.
Dialysate Leukocytes, sICAM-1, Hyaluronan and IL-6: Predictors of Outcome of Peritonitis?
Authors: Martikainen Terhi A. , Ekstrand Agneta V. , Honkanen Eero O. , Teppo Anna-Maija , Grönhagen-Riska Carola
Published: August 2004

Background/Aims: Despite effective antibiotic therapy, peritonitis still remains a major problem in peritoneal dialysis (PD). The aim of the present study was to investigate changes of CRP, dialysate leukocytes and IL-6, hyaluronan (HA) and sICAM-1 in dialysate during and after peritonitis and their association to the outcome of peritonitis. Methods: Dialysate IL-6, HA and sICAM-1 were measured at the onset and on day 4, at the end of the treatment and 2 months after onset of peritonitis. Furthermore, CRP and dialysate leukocytes were measured on days 1–4. Results: All measured soluble factors were higher on the first and fourth day than at the end of the treatment. sICAM-1 and HA were lower at the end of the treatment in patients who later had a relapse/re-infection. IL-6 remained higher 2 months after clinically cured peritonitis. CRP and dialysate leukocytes were higher on day 4 in patients with poor outcome. Conclusions: Peritonitis causes increased excretion of soluble factors. Low concentrations of sICAM-1 and HA at the end of the treatment were negative prognostic indicators. Higher IL-6 levels after peritonitis could be a sign of ongoing inflammation in the peritoneal membrane. Delayed decrease in CRP and dialysate leukocytes may indicate poor outcome.
Fractional Solute Removal and KT/V in Different Modalities of Renal Replacement Therapy
Authors: Waniewski Jacek , Lindholm Bengt
Published: August 2004

The efficacy of solute removal by renal replacement therapy can be assessed by the commonly used index of KT/V (the fraction of the volume cleared from a solute). Fractional solute removal (FSR, the fraction of the total amount of the solute that was removed) is an alternative index that may be more appropriate than KT/V for comparison of the efficacy of different treatment modalities. To elucidate the relationship between these two indexes, we propose to discriminate between two notions of clearance: (1) instantaneous clearance K = (solute removal rate)/CB, where CB is solute concentration in blood, and (2) treatment clearance KT = (average rate of solute removal per treatment)/CB0, where CB0 is CB at the beginning of the treatment. K is the clearance of the purification device (glomeruli, hemodialyzer or hemofilter) and the diffusive mass transport parameter (KBD, MTAC) for continuous ambulatory peritoneal dialysis (CAPD). For all modalities of renal replacement therapy: FSR = KTT/V, and KT generally decreases with the treatment time. For purification of a single compartment with a constant volume, V, using an open loop system (i.e. with no recirculation or dwelling of dialysis fluid, as in hemodialysis (HD), hemofiltration (HF) or in the native kidney), FSR is a function of only one lumped, nondimensional parameter, KT/VB, where VB is the distribution volume of the solute within the body. In contrast, if closed loop systems are applied, as for example in HD with recirculation of dialysis fluid (RD) or in peritoneal dialysis, FSR depends on two lumped, nondimensional parameters: KT/VB and KT/VD, where VD is the volume of dialysis fluid. It is necessary to discriminate between K and KT for analysis of dialysis dose. For HD and HF, FSR is a function of KT/V, whereas KT/V alone does not allow calculation of FSR for CAPD and RD. The current practice of using KTT/V for CAPD but KT/V for HD and HF leads to confusion because of the inconsistency in the interpretation of the quantitative prescription of dialysis dose. The application of FSR, instead of KT/V, for all treatment modalities may solve this dilemma. Furthermore, KTT/V (currently used only for CAPD) is equal to FSR for all treatment modalities. Both FSR and KT may be generalized to describe the total solute removal per treatment cycle composed from a few treatment sessions. A few different definitions of the adequacy parameters for the treatment cycle are formulated and discussed.
Pathogenic Factors in Vascular Dementia and Alzheimer’s Disease
Authors: Engelberg Hyman
Published: August 2004

The following areas are discussed in this review: atherogenesis; cerebrovascular factors; hypoperfusion; β-amyloid production; β-amyloid fibril formation; β-sheets; metal cations; reactive oxygen species/free radicals; chronic inflammatory factors; endogenous plasma heparin; lipoprotein lipase; polyamines; protein kinase C; casein kinases; phospholipase A2; serine proteases; myeloperoxidase; cyclooxygenase 2; cysteine proteases; caspases; proprotein convertases; aspartic proteases; cyclin proteinases; thrombin; tau hyperphosphorylation; advanced glycosylation end products; activator protein 1; calcium; apolipoprotein E Ε4; histamine; blood-brain barrier; glutamate; transglutaminase; insulin-like growth factor 1.
Evaluation of Recombinant and Native Timothy Pollen (rPhl p 1, 2, 5, 6, 7, 11, 12 and nPhl p 4)- Specific IgG4 Antibodies Induced by Subcutaneous Immunotherapy with Timothy Pollen Extract in Allergic Patients
Authors: Rossi R.E. , Monasterolo G.
Published: August 2004

Background: Allergen immunotherapy is a widely accepted treatment for IgE-mediated allergies. The evaluation of immunotherapy-induced IgG4 antibodies based on allergen extract is questionable because the amount of allergen-extract-specific IgG4 to individual disease-eliciting allergens cannot be determined using crude allergen extracts. In this study, we examined the specific IgE and IgG4 serum binding profiles to individual Phleum pratense allergens in grass-pollen-sensitive patients who had received grass-pollen-specific immunotherapy (SIT). Methods: The study included 33 patients from North-West Italy. All suffered from seasonal rhinoconjunctivitis and/or asthma. A modified ‘cluster’ regimen of injections of a standardized aluminium-adsorbed P.pratense extract, with once-weekly visits and 10 injections for 5 weeks followed by 3 weeks of maintenance injections was instituted. Patients’ sera were analyzed for specific IgE and IgG4 reactivity to individual P. pratense allergens (recombinant Phl p 1, Phl p 2, Phl p 5, Phl p 6, Phl p 7, Phl p 11, Phl p12 and native Phl p 4) and natural P. pratense extract using the Pharmacia CAP system. Results: IgE reactivities to new allergen components were not detected by CAP in treated patients after 15 weeks and a cumulative dose of approximately 65 µg of the major allergen Phl p 5. Patients lacking specific IgE reactivity towards individual allergens at the start of SIT did not produce significant levels of specific serum IgG4 to serum IgE-negative allergens. On the other hand, an increase in specific IgG4 only to allergens to which patients were previously sensitized was observed. Significant increases in specific IgG4 levels to rPhl p 1 (p < 0.05), 2 (p < (0.01), 5 (p < 0.0001), 6 (p < 0.0001), 7 (p < 0.05), 11 (p < 0.05) and nPhl p 4 (p < 0.01) were observed after P. pratense extract immunotherapy. No significant rPhl p 12-specific IgG4 antibody increase was documented after treatment. Conclusion: These findings suggest that Phl p 12 was underrepresented in the extract used, as indicated by the low specific IgG4 response induced by this grass-pollen-specific vaccine. Thus, the simple detection of specific serum IgG4 antibodies a few weeks after the start of SIT could represent a valuable tool to estimate the presence of relevant allergens in a given immunotherapeutic allergen extract.
Soluble Interleukin-5 Receptor Alpha Is Increased in Acute Exacerbation of Chronic Obstructive Pulmonary Disease
Authors: Rohde Gernot , Gevaert Philippe , Holtappels Gabriele , Fransen Lucie , Borg Irmgard , Wiethege Almut , Arinir Umut , Tavernier Jan , Schultze-Werninghaus Gerhard , Bachert Claus
Published: August 2004

Background: During chronic obstructive pulmonary disease (COPD) exacerbations (AE-COPD), an influx of eosinophils into the bronchial mucosa has been described. Eosinophilic cationic protein (ECP) and soluble interleukin-5 receptor α (sIL5Rα) are secreted by eosinophils and increased in eosinophilic airway diseases. Methods: We studied ECP and sIL5Rα expression in patients with COPD compared to healthy controls and smokers and investigated a possible association to viral exacerbations of COPD. Expression of sIL5Rα in serum was analyzed by ELISA and ECP by the Uni-Cap system. Induced sputum from patients with COPD was analyzed for six different respiratory viruses by nested PCR. Results: ECP and sIL5Rα were significantly elevated in AE-COPD subjects (n = 54) compared to healthy controls (n = 11, p = 0.018). Furthermore, there was a significant increase in sIL5Rα, but not in ECP, in 30 patients with virus-associated AE-COPD compared to smokers without COPD (n = 16) and healthy controls. The increase in FEV1 after resolution of the AE-COPD correlated with the decrease in sIL5Rα (r = 0.269, p = 0.034). Conclusions: sIL5Rα is increased in AE-COPD and not affected by smoking like ECP. sIL5Rα is increased in patients with virus-associated AE-COPD compared to smokers and controls. Concentrations of sIL5Rα mirror changes in the clinical status and lung function. These data support the involvement of eosinophils in acute exacerbations of COPD.
Polymorphisms in Interleukin-1β and Interleukin-1 Receptor Antagonist Genes Are Associated with Kidney Failure in Korean Patients with Type 2 Diabetes mellitus
Authors: Lee Sang Ho , Ihm Chun-Gyoo , Sohn Seong Dong , Lee Tae Won , Kim Myung Jae , Koh Gwanpyo , Oh Seung Joon , Woo Jeoung-Taek , Kim Sung Woon , Kim Jin Woo , Kim Young Seol , Lee Byung Cheol , Kim Seong Do , Cho Byoung Soo , Lee Hee-Jae , Chung Joo-Ho
Published: August 2004

Background/Aim: Cytokines play an important role in the pathogenesis of kidney diseases. The aim of the study was to investigate the impact of interleukin (IL)-1 cluster genes on diabetic nephropathy in Korean patients with type 2 diabetes mellitus (DM). Methods: We investigated –511 C/T polymorphism of IL-1β and tandem repeat polymorphism in intron 2 of IL-1 receptor antagonist in type 2 DM patients with end-stage kidney failure as compared with patients without nephropathy. Results: The IL1B2 allele was found more frequently in patients with kidney failure than in controls (57.4 vs. 46.1%, p < 0.05). An excessive homozygous carriage of IL1B2 was found in patients with kidney failure when compared with controls (30.5 vs. 18.3%, p < 0.05). The allelic frequency of IL1RN*2 was also higher in cases than in controls without nephropathy (8.4 vs. 2.8 %, p < 0.05). The carriage rate of IL1RN*2 was significantly associated with an increased risk of kidney failure (15.8 vs. 5.6%; OR 3.19, 95% CI 1.24–8.17). The risk of kidney failure was highest in those carrying both IL1RN*2 and IL1B2 (OR 3.90, 95% CI 1.34–11.40). Conclusion: IL1B2 and IL1RN*2 genotypes of the IL-1 cluster genes are associated with diabetic nephropathy in Korean patients with type 2 DM.
Gonadal Hormones Humour the Brain
Authors: Altman Jennifer
Published: August 2004

The relationship between the brain and the endocrine system is now seen to extend far beyond the regulation of somatic hormone production by the hypothalamus and pituitary: the brain itself can be considered both as an endocrine organ, producing hormones that act both within and outside the central nervous system, and as a target for hormones. The current extent of this concept with respect to the gonadal hormones was explored at a recent meeting (‘Hormones and the Brain’, Third Endocrinology Colloquium of the Fondation Ipsen, Paris, December 8, 2003). The discussion, reviewed in this article, ranged from intracellular signalling pathways and intercellular networks regulating hormone production and action in the central nervous system to hormone involvement in the generation of sexual behaviour and in development, plasticity, neuroprotection and repair. The hormonal contribution to psychiatric and neurodegenerative illnesses was also examined. The picture presented is complex, with layers of controls and with hormones that have diverse actions at different sites in the central nervous system. This richness of actions and functions is providing some interesting leads for developing new therapeutics.