bluuebunny/crossref_metadata_2025 huggingface dataset:
The relationship between population density, habitat position and habitat breadth within a neotropical forest bird community
Authors: Marsden Stuart J. , Whiffin Mark
Published: August 2003

We examined the relationship between local abundance, habitat position and habitat breadth across bird species in a large Atlantic forest reserve in Brazil. This appears to be the first such study for any rainforest taxon. Habitat position for a species was its mean foraging height, along with the mean scores on three principal habitat axes for census stations at which it was recorded. Habitat breadth was the standard deviation of recorded foraging heights and the standard deviations of “positive” station scores on the habitat axes. We also examined differences in habitat position and breadth between endemic and wide‐ranging taxa and amongst dietary groups. Amongst 31 species for which density estimation was possible, there were no correlations between local abundance and breadth of habitat use on any of the habitat axes. Breadth of habitat used did not vary with degree of endemism, but herbivores used a greater breadth of habitats on the axis describing canopy closure than did omnivores. Habitat position did not vary with endemic status, but herbivores preferred higher‐biomass habitats than faunivores, and higher foraging heights than either faunivores or omnivores. Local abundance was linked weakly to habitat position with commoner species tending to forage in the lower strata of open‐canopied areas. The 31 most commonly recorded species tended to occupy “middle‐range” habitat positions, while 28 rarer species occupied habitats toward one or other end of the vegetation axes. These results suggest an association between the local abundance of a species and its habitat position, and especially its preference for common or mid‐range habitats, rather than with its ability to utilise a wide range of habitats.
Habitat preference and habitat exploration in two species of satyrine butterflies
Authors: Leimar Olof , Norberg Ulf , Wiklund Christer
Published: August 2003

We compared the habitat preference and the mobility of different populations of primarily forest living, satyrine butterflies by observing them in a manipulated environment, containing different habitat types inside a large outdoor cage. The cage was 30 m long and divided into three parts. Each end of the cage contained a shady habitat, made to be similar to the floor of a forest with sunlit spots. In between these shady parts, there was a 14 m long open part, like a glade or a meadow. We performed two studies in the cage. In the first study, we compared a population of a species with very restricted distribution in Sweden,Lopinga achine, and a population of a widely distributed and expanding species,Pararge aegeria. We found that the two species had similar habitat preferences in the cage, but thatL. achinehad a lower rate of dispersal from one shady part of the cage to the other. In the second study, we compared two populations ofP. aegeria, a Swedish forest living population and a Madeiran population inhabiting a fairly open habitat. We found that, although individuals of the Swedish population avoided staying in the open, middle part of the cage, they dispersed between the shady parts of the cage at a higher rate than individuals of the Madeiran population. We argue that studies of the kind we performed can serve the purpose of testing hypotheses about habitat preference and mobility that derive from other field work or from information about distribution patterns.
Altitudinal body size clines: latitudinal effects associated with changing seasonality
Authors: Chown Steven L. , Klok C. Jaco
Published: August 2003

Within ectotherms, increases in body size with latitude are thought to be the consequence of the effect of a decline in development temperature, which results in a larger final body size. In contrast, latitudinal declines in body size are usually ascribed to limited resources. It has been suggested that if generation time is similar to or constitutes a significant proportion of the growing season length, then season length is likely to have a considerable influence on body size because of constraints on resource availability, so resulting in a decline in body size with temperature (latitude). However, if generation time declines relative to season length, resources effectively become available for longer. Temperature influences on growth and differentiation are likely to be most significant, resulting in an increase in body size with latitude. Here, we test the hypothesis by comparing intraspecific altitudinal body size clines in a monophyletic group of weevils from two regions that differ substantially in seasonality. On the relatively aseasonal Marion Island, body size increases with altitude, whereas on the more seasonal Heard Island the opposite is found. In addition, overlapping generations on Marion Island indicate year‐round resource availability, whereas more discrete generations on Heard Island indicate winter cessation of growth and development. Our data provide support for the hypothesis that the seasonality of resource availability has a major influence on body size clines. Furthermore, we argue that analysis of interspecific body size clines should be preceded by nested analyses of variance to determine the influence of clinal replacement of higher taxa on these patterns.
Effects of the Argentine ant Linepithema humile on seed dispersal and seedling emergence of Rhamnus alaternus
Authors: Gómez Crisanto , Pons Pere , Bas Josep M.
Published: August 2003

We studied influence of the Argentine ant's Linepithema humile occurrence on seed dispersal of Rhamnus alaternus (Rhamnaceae). Rhamnus alaternus is a fleshy fruit plant dispersed primarily by birds; the seeds have an elaiosome attractive to ants. The observations were made in two study plots of Mediterranean cork‐oak forests (one invaded and the other not invaded by L. humile) over two years. For R. alaternus, presence of L. humile was associated with of the following: reduction of seed transport to ant nests (80.2% of seed offered were removed in non‐invaded vs 7.1% in invaded area), a shorter seed dispersal distance (mean=90.2 cm in non‐invaded vs 1.1 cm in invaded area), increase in seed retention time on the soil surface (median time in non‐invaded was 50 vs 209.2 min in invaded area) and increased vulnerability to predation. In addition there was lower probability of seedling emergence, due to little elaiosome removal from the seeds (82.0% of emergence for seeds without elaiosome and 57.3% for seeds with elaiosome). These results, similar to findings obtained in South African fynbos, confirm that the Argentine ant invasion can strongly affect ecosystem processes in the Mediterranean biome.
Are forest birds categorised as “edge species” strictly associated with edges?
Authors: Imbeau Louis , Drapeau Pierre , Mönkkönen Mikko
Published: August 2003

In recent years, studies of bird‐habitat relationships undertaken in the context of habitat fragmentation have led to the widespread use of species categorisation according to their response to edge alongside mature forest patches (edge species, interior species, interior‐edge generalist species). In other research contexts, especially in less fragmented landscapes dominated by a forested land base in various age classes, bird‐habitat relationships are often described in relation to their use of various successional stages (early‐successional species, mature forest species, generalist species). A simple comparison of these two commonly‐used classifications schemes in a close geographical range for 60 species in eastern North America as well as for 36 species in north‐western Europe clearly reveals that in these two particular biomes the two classifications are not independent. We believe that this association is not only a semantic issue and has important ecological consequences. For example, almost all edge species are associated with early‐successional habitats when a wide range of forest age‐classes are found in a given area. Accordingly, we suggest that most species considered to prefer edge habitats in agricultural landscapes are in fact only early‐successional species that could not find shrubland conditions apart from the exposed edges of mature forest fragments. To be considered a true edge species, a given species should require the simultaneous availability of more than one habitat type and consequently should be classified as a habitat generalist in its use of successional stages. However, 28 out of 30 recognised edge species were considered habitat specialists in terms of successional status. Based on these results, we conclude that “real edge species” are probably quite rare and that we should make a difference between true edge species and species which in some landscapes, happen to find their habitat requirements on edges.
Do habitat association models have any generality? Predicting skylark Alauda arvensis abundance in different regions of southern England
Authors: Whittingham Mark J. , Wilson Jeremy D. , Donald Paul F.
Published: August 2003

Much of conservation science is based upon determining the use by organisms of different resources. However, the field data used to construct habitat association models generally come from a small number of sites covering a fraction of the area of interest. It is important therefore to assess the generality of those models for species occurring over large geographical areas. In this paper we test the generality of models describing skylark Alauda arvensis abundance across farmland in southern England in relation to crop type, crop structure and field structure (i.e. height of surrounding boundaries). Skylarks responded to most predictors we measured in similar ways across three regions of differing farming practices (arable‐dominated, pasture‐dominated and a mixture of the two). Most of the regional differences in habitat associations could be related to differences in the speed of crop development. For example, the sowing of cereals in spring, a much lauded strategy to increase skylark populations, is likely to have less of an effect in regions where cereal development is slow than in regions where it is fast.  Most studies that explicitly test the performance of a model developed in one place elsewhere use presence/absence models. We adopt a more sensitive and novel approach by using counts. We found regression equations developed in one region performed poorly when tested as a direct predictor (i.e. a 1:1 relationship) on data from other regions. However, the skylark territories observed in any one region were positively correlated with the territory numbers predicted by models built using data from other regions, so models were good predictors of relative abundance.  The results suggest that, for this species at least, conservationists should have confidence when advocating management strategies based upon habitat‐association models and extrapolating their generality to other areas. However, our results warn against using regression equations developed in one place to make absolute quantitative predictions elsewhere. Decision‐makers should beware of using models in this way.
Area, altitude and aquatic plant diversity
Authors: Jones J. Iwan , Li Wei , Maberly Stephen C.
Published: August 2003

Several explanations have been given for the decline in species richness with altitude. However, separating the influences of altitude, area, and isolation is difficult because of the conical shape of mountains. We used species lists of aquatic plants from >300 lakes in a small geographical area to investigate the influence of altitude on species richness. Altitude and/or surface area were better predictors of species richness than any measure of water chemistry. The surface area and depth of individual lakes were not related to altitude, neither was the degree of isolation from other waterbodies. Although species range size increased with altitude, range sizes of all but the rarer species (in the data set) encompassed the lowest altitudes, indicating species loss rather than turnover and no influence of the Rapoport rescue effect. Nevertheless we found a decline in species richness with altitude, additive to the effect of area. Species were ascribed to attribute groups according to an a priori classification based on morphological and life‐history traits. The number of attribute groups and number of species within each group increased with area, suggesting both increased diversity and coexistence within niches. With altitude, the number of attribute groups declined, but the number of species per group increased, consistent with a loss of richness and reduced competition. The species remaining at high altitudes were characterised by stress tolerant traits, associated with sites of low productivity.

Our results suggest an absolute effect of altitude on species richness, irrespective of other influences and consistent with a decline in productivity.
A test of the relationship between seasonal rainfall and saguaro cacti branching patterns
Authors: Drezner Taly Dawn
Published: August 2003

Reproductive output, as well as photosynthetically active radiation interception and CO2 uptake, increase as saguaro cacti Carnegiea gigantea (Engelm.) Britt. and Rose branch, and branching increases with increasing moisture. The Sonoran Desert experiences distinct summer and winter precipitation regimes that vary in both geography and scale. Many aspects of saguaro ecology are known to depend on the summer rains, which has resulted in an emphasis on summer rains in the literature. Similarly, branching studies have been limited geographically to areas that receive relatively high amounts of summer rainfall. These studies, therefore, attribute branching patterns to the summer (or possibly annual) rains, and conclusions reflect the summer precipitation bias.  Environmental variability in space was explored in the present study to investigate saguaro branching patterns. I collected height and branching data in thirty saguaro populations across their American range. Stepwise regression was used to determine which climate, vegetation and soil variables best predict branching. Contrary to the literature, this study found that winter precipitation, particularly from January to April, was the best predictor of branching, not summer or annual rain. Surprisingly, the relationship between the summer monsoons (July and August precipitation) and branching was negative. This is likely due to the fact that summer and winter rainfall patterns are geographically distinct. Winter precipitation appears to play a key role in branching, and thus in seed production. This suggests that saguaros benefit from moisture during the winter, possibly utilizing cold‐season rains for increasing their reproductive output through branching, and challenging the view that the summer rains dominate virtually every aspect of the saguaro life‐cycle, and creating a more balanced view of saguaro ecology.
Minichromosome maintenance 2 expression is correlated with mode of invasion and prognosis in oral squamous cell carcinomas
Authors: Kodani Isamu , Osaki Mitsuhiko , Shomori Kohei , Araki Kunio , Goto Eizo , Ryoke Kazuo , Ito Hisao
Published: August 2003

Background:  This study examined the immunohistochemical expression of cell‐cycle related molecules as well as cell proliferation and pathologic findings in oral squamous cell carcinoma (SCC) in order to clarify their pathobiologic and prognostic significance.

Methods:  A total of 46 oral SCC specimens were analyzed using Ki‐67, minichromosome maintenance 2 (MCM2), p53, p27, p21, and TUNEL. Aspects including tumor differentiation, mode of carcinoma invasion, tumor metastasis, and patient prognosis were compared among the specimens.

Results:  A significantly higher MCM2 labeling index (LI) was observed in the moderately differentiated SCCs when compared to the well‐differentiated SCCs (P < 0.05). The higher MCM2 LI was correlated with mode of invasion Grade 4 (infiltrative growth) and patient prognosis. In contrast, the LIs of Ki‐67, TUNEL‐signal, p53, p27, and p21 were not correlated with patient prognosis.

Conclusion:  Higher MCM2 LI provides useful information for patient prognosis in oral SCCs.
Dentigerous cyst versus unicystic ameloblastoma – differential diagnosis in routine histology
Authors: Dunsche Anton , Babendererde Ortwin , Lüttges Jutta , Springer Ingo N. G.
Published: August 2003

Background:  Unicystic ameloblastomas (UAs) and dentigerous cysts (DCs) have an identical clinical and radiographic appearance. Some subtypes of UAs have a better prognosis than solid or multicystic ameloblastomas, and simple enucleation is the adequate treatment. The present study was designed to test the hypothesis that UAs with small islands of ameloblastomatous epithelium may be misdiagnosed as a DC or keratocyst if no more than two histologic sections are examined.

Methods:  A total of 101 resection specimens from 22 women and 73 men (mean age: 46.5 years) were selected, all showing the clinical and radiographic features of a DC. Only cysts with a minimum diameter of 15 mm in the panoramic X‐ray were considered for the present investigation. The histopathologic diagnosis had been routinely established by examining two sections. For our study, the specimens were investigated by step sections at 50 µm and by staining of 5 µm thin sections with hematoxylin and eosin (H&E) at 1 mm levels. An average of 15 slides were evaluated per case.

Results:  Microscopic examination of the step sections did not reveal ameloblastomatous epithelium in the cyst lining epithelium of the 101 cases. Thus, every primary diagnosis of a dentigerous cyst was confirmed. In four cases, additional rather large odentogenic cell nests were detected with palisading of basaloid cells, while there was a lack of other signs of ameloblastic differentiation. All lesions were completely resected, and no additional treatment was performed.

Conclusions:  Step sectioning of larger DCs may reveal associated odontogenic cell nests in some cases but does not lead to the detection of formerly missed ameloblastic cells. Thus, unicystic ameloblastomas are not misdiagnosed if only two slides are prepared for routine diagnosis of DCs.
Endovascular papillary angioendothelioma (Dabska tumor) of the tongue: report of a case
Authors: Takaoka Kazuki , Sakurai Kazunari , Noguchi Kazuma , Hashitani Susumu , Urade Masahiro
Published: August 2003

Endovascular papillary angioendothelioma (EPA), known as Dabska tumor, is a very rare vascular neoplasm that usually occurs in the skin or subcutis of infants and young children. There is no previous report of EPA appearing in the oral cavity. Here, we present an exceptionally rare case of EPA of the tongue in a 67‐year‐old man. A well‐defined, reddish tumor measuring 11 mm × 8 mm × 7 mm existed at the submucosal area of the left tongue margin. Microscopic examination of an excisional biopsy specimen revealed the endothelioid tumor cells showing a papillary growth pattern, such as blood vessel‐like structures. Immunohistochemical studies showed positive reactivities for CD31, CD34, α‐smooth muscle actin, and factor VIII‐related antigen in most of the tumor cells and CD68 in some tumor cells. Based on these observations, the tumor was diagnosed as an EPA.
Loss of heterozygosity at APC and MCC genes of oral cancer and leukoplakia tissues from Indian tobacco chewers
Authors: Sikdar Nilabja , Paul Ranjan Rashmi , Panda Chinmay K. , Banerjee Sanat K. , Roy Bidyut
Published: August 2003

Background:  Loss of heterozygosity (LOH) at tumor suppressor genes, such as adenomatous polyposis coli (APC) and mutated in colon cancer (MCC) genes, is one of the early events in carcinogenesis of oral tissue in Caucasian and Chinese patients. We wanted to check whether it is also true in Indian oral pre‐cancer and cancer patients.

Methods:  Loss of heterozygosity at APC and MCC genes was investigated in 57 and 40 unrelated primary oral leukoplakia (a pre‐cancerous lesion) and squamous cell carcinomas (SCC), respectively, by polymerase chain reaction.

Results:  In these samples, most of the leukoplakia patients had tobacco smoking habit whereas majority of cancer patients had tobacco chewing habit. LOH at APC gene was observed in 4 of 16 (25%) and 1 of 29 (3%) informative tumor and leukoplakia DNAs from tobacco chewers, respectively. LOH at MCC gene was not detected either in tumor or in leukoplakia DNAs.

Conclusion:  This infrequent LOH at APC gene of pre‐cancer and cancer tissues suggests that it may not be an early event in oral carcinogenesis in these patients.
Maxillary odontogenic keratocyst with respiratory epithelium: a case report
Authors: Yamazaki Manabu , Cheng Jun , Nomura Tsutomu , Saito Chikara , Hayashi Takafumi , Saku Takashi
Published: August 2003

We report a case of odontogenic keratocyst with a respiratory epithelial lining and a malformed impacted tooth in the maxilla of a 39‐year‐old Japanese female who suffered from swelling symptoms for half a year. CT examinations revealed an air‐filled cystic lesion with an impacted tooth crown in the maxillary bone which expanded to the nasal cavity as well as to the maxillary sinus. Histopathologically, the surgically removed cyst wall consisted of fibrous granulation tissue with a lining of parakeratinized squamous epithelium as well as ciliated pseudostratified epithelium and with retention of desquamated keratin materials in the lumen. The impacted tooth was malformed lacking a root portion. We discuss the frequency of respiratory epithelium in odontogenic keratocysts.
Oral nicorandil‐induced lesions are not aphthous ulcers
Authors: Boulinguez S. , Sommet A. , Bédane C. , Viraben R. , Bonnetblanc J. M.
Published: August 2003

Objectives:  (i) To accurately define these lesions determining whether oral nicorandil‐induced lesions are aphthous ulcers; (ii) To determine clinical characteristics of oral nicorandil‐induced lesions.

Materials and methods:  Two slide conferences were held. A total of 60 dermatologists assigned diagnosis and clinical criteria to 11 photographs of oral nicorandil‐induced lesions. Two slides were randomly selected and duplicated to be used as control. The panel of slides included independent lesions and photographs of different lesions of the same patient. Statistical analysis used χ2‐test, estimation of the percentage interobserver agreement, and kappa‐values.

Results:  The diagnosis of non‐aphthous ulcer (71.8%) was significantly held in comparison with the diagnosis of oral aphthous ulcer (28.2%; P < 0.001). To differentiate aphthous ulcer from non‐aphthous ulcer, physicians significantly used three clinical criteria. The diagnosis of non‐aphthous ulcer were significantly associated with the absence of yellow‐based ulceration (P < 0.001), with the linear shape (P = 0.006) and the absence of inflammatory halo (P = 0.003).

Conclusion:  Oral nicorandil‐induced lesions are not aphthous ulcers. We propose that at this stage of our knowledge, oral nicorandil‐induced ulcer is the most suitable terminology.
Expression of vascular endothelial growth factor‐C correlates with the lymphatic microvessel density and the nodal status in oral squamous cell cancer
Authors: Sedivy Roland , Beck‐Mannagetta Johann , Haverkampf C. , Battistutti Walter , Hönigschnabl Selma
Published: August 2003

Background:  The cause of preferential metastatic spreading to cervical lymph nodes in oral squamous cell cancer (SCC) is not quite clear. As the density of microvessels may influence the metastatic behaviour, we were interested in how the density of blood/lymphatic microvessels are related to primary SCC and the clinical course of the disease.

Methods:  Lymphatic and blood microvessels of 28 patients with oral SCC were identified immunohistochemically by antibodies against podoplanin and CD34, respectively. Lymphatic microvessel density (LVD) and blood microvessel density (MVD), and the expression of VEGF‐C were determined. These findings were compared with the long‐term clinicopathological data of the patients.

Results:  LVD and MVD were significantly higher than in control tissues. The amount of lymphatic microvessels correlated positively with the expression of VEGF‐C, the tumour grade, the nodal status and with later appearing metastasis. The latter three parameters, however, did not influence the clinical course of the disease.

Conclusions:  VEGF‐C expression in oral SCC triggers lymphatic angiogenesis, which may result in a higher risk for cervical lymph node metastasis. The angiogenetic effect of VEGF‐C may also favour the onset of late lymphatic and haematogenous metastases.
Multiple primary tumours following head and neck cancer in southern England during 1961–98
Authors: Warnakulasuriya K. A. A. S. , Robinson D. , Evans H.
Published: August 2003

Background:  Successful initial treatment of oral and oro‐phayngeal cancer has led to the emergence of second primary tumours (SPTs). Population data are meagre.

Methods:  Occurrence of multiple primary cancers following a malignancy in a head and neck site was computed using data from a population‐based cancer registry covering a population of 14 million.

Results:  Among 59,958 subjects reported to the registry, 5.5% males and 3.6% females developed a second primary cancer. At the sites studied, a total of 2771 second primary cancers were found, compared with an expected number of 2341. The standardised incidence ratio (SIR) for contracting a new primary cancer was 1.14 (95% CI = 1.09–1.19) for men and 1.34 (95% CI = 1.24–1.44) for women. There was a significantly increased risk for a second cancer in most of the upper aerodigestive tract sites that are generally regarded as tobacco associated, with an SIR for subsequent oral cancer of 5.56 in men and 15.31 in women. Subjects first detected with a pharyngeal cancer experienced the highest SIR for a subsequent tumour. Excluding tobacco‐associated sites, the risk of a subsequent cancer was not significantly raised in either sex (SIR 0.87 (95% CI 0.81–0.93) for men; SIR 0.99 (95% CI 0.90–1.09) for women).

Conclusions:  The relative risk for multiple primary cancer was higher in younger subjects, those detected with a head and neck cancer during the 1990s as compared with earlier decades of the study, and among patients who received radiotherapy for their first tumour. By 20 years from the time of the first head and neck cancer, we estimate that approximately 30% of male patients and 20% of female patients will have developed an SPT.
The biphasic differential expression of the cellular membrane protein, caveolin‐1, in oral carcinogenesis
Authors: Hung Kai‐Feng , Lin Shu‐Chun , Liu Chung‐Ji , Chang Che‐Shoa , Chang Kuo‐Wei , Kao Shou‐Yen
Published: August 2003

Background:  The increased expression of Cav‐1 is seen in various cancers from prostate, esophagus, colon, breast and pancreas yet the information regarding the correlation between the expression of Cav‐1 and oral cancer is blind. Thus, the expression profile of caveolin‐1 (Cav‐1) in oral carcinogenesis and the correlation to the clinicopathologic covariates are examined in this study.

Methods:  Immunohistochemistry was used to detect Cav‐1 expression in non‐cancerous matched tissues (NCMT; n = 12), and tissue from normal oral mucosa (NOM; n = 12), oral pre‐cancer lesions (OPL; n= 17), primary oral squamous cell carcinoma (POSCC; n = 47) and metastatic OSCC (MOSCC; n = 8). The Cav‐1 expression was correlated to the age, site, areca use, stage, size, nodal involvement, and differentiation stage. Western blot was used to confirm the specificity of antibody and to follow changes in Cav‐1 expression.

Results:  The Cav‐1 immunoreactivity increased significantly from 8% in NOM and 17% in NCMT to 53% in OPL and 79% in POSCC. In addition, lymph node metastasis (LNM) was present in 62% of Cav‐1(+) POSCCs, but only in 10% of Cav‐1(–) POSCCs. Remarkably, only 38% of MOSCCs had Cav‐1 immunoreactivity.

Conclusion:  An increased Cav‐1 expression is seen in the stepwise carcinogenesis from NOM, NCMT, OPL to POSCC. The decrease in expression from the POSCC to MOSCC indicates the value to explore its biphasic functions in oral carcinogenesis. Whether Cav‐1 is an important predictor or prognosis for survival still awaits the extension of clinical follow‐up.
ECL Cell Histamine Mobilization Studied byGastric Submucosal Microdialysis in Awake Rats:Methodological Considerations
Authors: Ericsson Peter , Norlén Per , Bernsand Maria , Alm Per , Höglund Peter , Håkanson Rolf
Published: August 2003

Abstract: The ECL cells are endocrine/paracrine cells in the acid‐producing part of the stomach. They secrete histamine in response to circulating gastrin. Gastric submucosal microdialysis has been used to study ECL‐cell histamine mobilization in awake rats. In the present study we assess the usefulness and limitations of the technique. Microdialysis probes were implanted in the gastric submucosa. Histological analysis of the stomach wall around the probe revealed a moderate, local inflammatory reaction 1–2 days after implantation; the inflammation persisted for at least 10 days. Experiments were conducted 3 days after the implantation. The “true” submucosal histamine concentration was determined by perfusing at different rates (the zero flow method) or with different concentrations of histamine at a constant rate (the no‐net‐flux method): in fasted rats it was calculated to be 87±5 (means±S.E.M.) nmol/l and 76±9 nmol/l, respectively. The corresponding histamine concentrations in fed rats were 93±5 and 102±8 nmol/l, respectively. With a perfusion rate of 74 μl/hr the recovery of submucosal histamine was 49%, at 34 μl/hr the recovery increased to 83%. At a perfusion rate below 20 μl/hr the microdialysate histamine concentration was close to the actual concentration in the submucosa. The ECL‐cell histamine mobilization was independent of the concentrations of Ca2+ in the perfusion medium (0–3.4 mmol/l Ca2+). In one experiment, histamine mobilization in response to gastrin (10 nmol/kg/hr subcutaneously) was monitored in rats pretreated with prednisolone (60 mg/kg) or indomethacin (15 mg/kg). The two antiinflammatory agents failed to affect the concentration of histamine in the microdialysate either before or during the gastrin challenge, which was in accord with the observation that the inflammatory reaction was modest and that inflammatory cells were relatively few around the probe and in the wall of the probe. In another experiment, rats were given aminoguanidine (10 mg/kg) or metoprine (10 mg/kg) 4 hr before the start of gastrin infusion (5 nmol/kg/hr intravenously). Metoprine (inhibitor of histamine N‐methyl transferase) did not affect the microdialysate histamine concentration, while aminoguanidine (inhibitor of diamine oxidase) raised both basal and gastrin‐stimulated histamine concentrations. We conclude that microdialysis can be used to monitor changes in the concentration of histamine in the submucosa of the stomach, and that the inflammatory reaction to the probe is moderate and does not affect the submucosal histamine mobilization.
The CB1 Cannabinoid Receptor Agonist, HU‐210, Reduces Levodopa‐Induced Rotations in 6‐Hydroxydopamine‐Lesioned Rats
Authors: Gilgun‐Sherki Yossi , Melamed Eldad , Mechoulam Raphael , Offen Daniel
Published: August 2003

Abstract: Parkinson's disease is a chronic neurodegenerative disease of the extrapyramidal system associated with dopaminergic neuronal loss in the basal ganglia. However, several other neurotransmitters, such as serotonin, γ‐amino‐butyric acid and glutamate, are also related to the symptoms of Parkinson's disease patients and their response to levodopa treatment. The co‐expression of cannabinoid and dopamine receptors in the basal ganglia suggests a potential role for endocannabinoids in the control of voluntary movement in Parkinson's disease. In the present study we treated unilaterally 2,4,5‐trihydroxyphenethylamine (6‐hydroxydopamine)‐lesioned rats with the enantiomers of the synthetic cannabinoid 7‐hydroxy‐Δ6‐tetrahydrocannabinol 1,1‐dimethylheptyl. Treatment with its (−)− (3R, 4R) enantiomer (code‐name HU‐210), a potent cannabinoid receptor type 1 agonist, reduced the rotations induced by levodopa/carbidopa or apomorphine by 34% and 44%, respectively. In contrast, treatment with the (+)− (3S, 4S) enantiomer (code‐name HU‐211), an N‐methyl‐D‐aspartate antagonist, as well as the psychotropically inactive cannabis constituent: cannabidiol and its primary metabolite, 7‐hydroxy‐cannabinol, did not show any reduction of rotational behavior. Our results indicate that activation of the CB1 stimulates the dopaminergic system ipsilaterally to the lesion, and may have implications in the treatment of Parkinson's disease.
Novel Effect of N‐Palmitoyl‐L‐Serine Phosphoric Acid on Cytosolic Ca2+ Levels in Human Osteoblasts
Authors: Jan Chung‐Ren , Lu Yih‐Chau , Jiann Bang‐Ping , Chang Hong‐Tai , Wang Jue‐Long , Chen Wei‐Chung , Huang Jong‐Khing
Published: August 2003

Abstract: The effect of N‐palmitoyl‐L‐serine phosphoric acid (L‐NASPA), which has been used as an inhibitor of lysophosphatidic acid receptors, on intracellular Ca2+ concentration ([Ca2+]i) in human osteosarcoma MG63 cells was measured by using fura‐2. L‐NASPA (0.1–10 μM) caused a rapid and transient plateau [Ca2+]i rise in a concentration‐dependent manner (EC50=0.5 μM). The L‐NASPA‐induced [Ca2+]i rise was partly reduced by removal of extracellular Ca2+ but was not altered by L‐type voltage‐gated Ca2+ channel blockers. In Ca2+‐free medium, thapsigargin, an inhibitor of the endoplasmic reticulum Ca2+‐ATPase, induced a [Ca2+]i rise, after which the increasing effect of L‐NASPA on [Ca2+]i was completely inhibited; also, pretreatment with L‐NASPA partly reduced thapsigargin‐induced [Ca2+]i rise. U73122, an inhibitor of phospholipase C, abolished histamine (but not L‐NASPA)‐induced [Ca2+]i rise. Overnight incubation with 1 μM L‐NASPA did not affect cell proliferation, but 10–20 μM L‐NASPA exerted 4% and 15% inhibition, respectively. Collectively, L‐NASPA rapidly increased [Ca2+]i in MG63 cells by evoking both extracellular Ca2+ influx and intracellular Ca2+ release, and is cytotoxic at higher concentrations.
Modulation of GABAA Receptors and Neuropeptide Secretion by the Neurosteroid Allopregnanolone in Posterior and Intermediate Pituitary
Authors: Hansen Suzanne L. , Fjalland Bjarne , Jackson Meyer B.
Published: August 2003

Abstract: A number of neurosteroids bind to GABAA receptors and alter their responsiveness to neurotransmitters. Considerable effort has been devoted to understanding how this form of receptor modulation alters inhibitory synaptic function. Neurosteroid‐sensitive GABAA receptors have also been demonstrated in many endocrine cells, but little is known about how neurosteroids modulate the release of hormones. Here, the action of allopregnanolone, a neurosteroid that enhances GABAA receptor‐mediated responses, was investigated in posterior pituitary nerve terminals and intermediate pituitary endocrine cells. Patch clamp recordings showed that GABA‐evoked currents were enhanced to similar degrees and with similar concentration dependences in both locations. An organ bath preparation of the neurointermediate lobe was used to investigate drug effects on secretion of vasopressin and α‐melanocyte stimulating hormone. GABA increased the basal release of vasopressin and α‐melanocyte stimulating hormone from the posterior and intermediate pituitary lobe, respectively, an effect that could be blocked by picrotoxinin. Vasopressin release evoked by electrical stimulation was also examined, and a small statistically significant inhibition by 5 μM GABA was observed. Allopregnanolone increased the basal release of vasopressin, and this effect was blocked by the GABAA receptor antagonist picrotoxinin. Allopregnanolone had no effect in conjunction wıth GABA. In contrast to the posterior lobe, allopregnanolone had no effect on release from the intermediate lobe. Thus, allopregnanolone in physiological relevant concentrations modulates GABAA receptors in both the posterior and intermediate lobes, but only affects hormone release in the posterior lobe.
Gastrointestinal and Systemic Uptake of Bismuth in Mice after Oral Exposure
Authors: Larsen Agnete , Martiny Nargot , Stoltenberg Meredin , Danscher Gorm , Rungby Jørgen
Published: August 2003

Abstract: Bismuth compounds have been used in medicine for more than 200 years. In recent years, bismuth has gained renewed interest as a remedy for eradication of gastrointestinal pathogens, especially Helicobacter pylori. In this study we describe the anatomical distribution of bismuth in the gastrointestinal tract and other organs after oral exposure in a mouse model. After exposure of the experimental animals to ranitidine bismuth citrate or bismuth citrate, we used the autometallographic silver enhancement technique to demonstrate the presence of bismuth in tissue samples from the gastrointestinal tract, liver, spleen, thymus, kidney and lymph nodes. We exposed cultured murine peritoneal macrophages to bismuth citrate and examined the bismuth accumulation over time. We found that in the mouse bismuth is absorbed systemically after a single dose of either compound, ranitidine bismuth more easily than bismuth citrate. Uptake could be shown in the stomach, duodenum, ileum and kidney for hours after exposure. Weeks after the exposure, deposits of bismuth were found in lymph nodes, liver, spleen and kidney as well as in macrophages in the gastrointestinal lamina propria. At the subcellular level, bismuth was found exclusively in lysosomes, primarily in macrophages and dendritic cells. Subsequent analyses of macrophage cultures showed lysosomal accumulations to be time and dose dependent.
The math of making mutant mice
Authors: Williams R. W. , Flaherty L. , Threadgill D. W.
Published: August 2003

More than ten large‐scale mutagenesis projects are now generating hundreds of novel mouse mutants. Projects employ a wide variety of strategies and screens: targeting as much as the whole genome, part of a chromosome or just single genes. In this commentary, we consider the pros and cons of different tactics. We highlight issues of cost, efficiency and defend the impact of this mutagenesis program in an era of sophisticated conditional knockouts and advanced transgenic lines. Given the significant difficulties of adequately phenotyping and mapping randomly generated mutations that cover the whole genome, we tend to favor regional and gene‐targeted screens. Whatever the choice of method, whole genome sequence data combined with detailed transcriptome and proteome surveys promise to significantly improve the efficiency with which series of mutations in a large subset of mammalian genes can be generated and cloned.
Memory enhancement: the progress and our fears
Authors: Gerlai R.
Published: August 2003

In a recent article Rose (2002) raises numerous crucial issues with regard to the research into and the use of cognition or memory enhancing agents. Although development of ‘smart’ drugs is in its infancy, his paper delineates some issues society may have to face when these drugs arrive. Questions about the development of such drugs may be interesting to several readers of Genes Brain and Behavior given the wealth of information expected to be gained on brain function from studies using genetic approaches including mutagenesis, transgenic techniques and genomics in general. Besides the scientific questions, several ethical issues may need to be addressed that are of interest to us all. Rose (2002) discusses some of these questions, but perhaps presents a too negative view on the problems, especially with regard to the present and future of memory research. This paper is intended to focus mainly on the scientific questions and argues that our fear of complex ethical problems should not make us throw the baby (i.e., our research and discoveries) out with the bath water.
Impaired discrimination of and aversion to parasitized male odors by female oxytocin knockout mice
Authors: Kavaliers M. , Colwell D. D. , Choleris E. , Ågmo A. , Muglia L. J. , Ogawa S. , Pfaff D. W.
Published: August 2003

A major cost of social behavior is the increased risk of exposure to parasites, with animals utilizing social information to recognize and avoid infected conspecifics. In mice, females can discriminate between infected and uninfected males on the basis of social cues, displaying aversive responses to the odors of infected males. In the present study, using female mice whose gene for oxytocin (OT) has been selectively deleted (OT knockout mice (OTKO)), we show that at least one normal allele for OT is required for the mediation of the recognition and avoidance of parasitized males. Female wild type (OTWT) and heterozygous (OTHZ) mice distinguished between the odors of individual males infected with the louse, Polyplax serrata, and uninfected males while the KO mice did not. Exposure to the odors of infected males induced analgesia in OTWT and OTHZ females, with OTKO females displaying attenuated analgesia. OTWT and OTHZ females, but not the OTKO females, also distinguished between the odors of novel and familiar infected males and modulated their analgesic responses on the basis of prior familiarity. In an odor choice test, OTWT and OTHZ females displayed a marked initial choice for the odors of uninfected males, whereas the OTKO females showed no consistent choice. This impairment was specific to the odors of infected males. OTKO females displayed normal analgesic responses to another aversive social odor, that of a stressed male, and an aversive non‐social odor, that of a cat. The OTKOs had normal non‐social olfactory memory, but were impaired in their social odor memory. These findings indicate that a normal OT gene comprises an essential part of the central recognition mechanism whereby females can both reduce the transmission of parasites to themselves and select for parasite‐free males.
Strain differences in three measures of ethanol intoxication in mice: the screen, dowel and grip strength tests
Authors: Crabbe J. C. , Cotnam C. J. , Cameron A. J. , Schlumbohm J. P. , Rhodes J. S. , Metten P. , Wahlsten D.
Published: August 2003

Mice from 8 to 21 inbred strains were tested for sensitivity to ethanol intoxication using a range of doses and three different measures: the screen test, the dowel test and a test of grip strength. Strains differed under nearly all conditions. For the dowel test, two dowel widths were employed, and mice were tested immediately or 30 min after ethanol. For the dowel and screen tests, low doses failed to affect some strains, and the highest doses failed to discriminate among mice, maximally affecting nearly all. For grip strength, a single ethanol dose was used, and mice of all strains were affected. Pharmacokinetic differences among strains were significant, but these could not account for strain differences in intoxication. For doses and test conditions in the middle range, there were only modest correlations among strain means within a test. In addition, genotypic correlations across tests were modest to quite low. These results suggest that different specific versions of a test reflect the influence of different genes, and that genetic influences on different tests were also distinct.
Differences among eight inbred strains of mice in motor ability and motor learning on a rotorod
Authors: McFadyen M. P. , Kusek G. , Bolivar V. J. , Flaherty L.
Published: August 2003

The rotorod is commonly used to assess motor ability in mice. We examined a number of inbred strains to determine whether there is genetic variability in rotorod performance and motor learning. Mice received three trials per day for three days in a modified accelerating rotorod paradigm, and active rotation performance was calculated for each day. Male and female 129S1/SvImJ, A/J, BALB/cByJ, C3H/HeJ, C57BL/6J, CBA/J, DBA/2J and FVB/NJ mice were tested. Strain and sex differences were observed in motor performance. Motor learning also differed across strains, as some strains showed an improvement in performance over the three days while other strains did not. In certain strains the weight and body length of the mouse correlated with rotorod performance. The role of vision in motor performance on the rotorod was assessed by a comparison of C3H/HeJ mice (with retinal degeneration) and congenic C3A.BLiA‐Pde6b+ (Pdeb+) mice (without retinal degeneration). The sight‐impaired C3H mice stayed on the rotorod longer than did their sighted Pdeb+ partners, although both strains improved across days. Thus, we have demonstrated a genetic component in rotorod performance, and we have shown that factors other than inherent motor ability can contribute to rotorod performance in mice.
Down regulation of cerebellar memory related gene‐1 following classical conditioning
Authors: D'Agata V. , Schreurs B. G. , Pascale A. , Zohar O. , Cavallaro S.
Published: August 2003

We have isolated and characterized the mRNA of a mouse gene named cerebellar memory related gene‐1, previously found by microarray analysis to be differentially expressed following classical conditioning of the rabbit nictitating membrane response. Quantitative RT‐PCR analysis showed a significant reduction in mRNA expression in cerebellar lobule HVI but not in the hippocampus of rabbits that received classical conditioning compared to control rabbits that received either unpaired stimulus presentations or were simply restrained. The mouse mRNA encodes a protein of 485 amino acids that includes different potential post‐translational modification sites and five copies of the WD‐repeat suggesting involvement in protein–protein interaction and regulatory function. In‐situ hybridization experiments show highly localized expression of the transcript in mouse brain with the highest expression levels located in the cerebellum, hippocampus and cortex. Taken together, our results reveal a novel gene encoding a WD‐repeat protein that is down‐regulated in cerebellar lobule HVI as a result of learning and memory.
Genetic architecture of the mouse hippocampus: identification of gene loci with selective regional effects
Authors: Peirce J. L. , Chesler E. J. , Williams R. W. , Lu L.
Published: August 2003

We recently mapped two quantitative trait loci that have widespread effects on hippocampal architecture in mouse:Hipp1aandHipp5a. We also noted remarkable strain differences in the relative sizes of different hippocampal regions. Estimated heritable variation for these differences was 42% in hippocampus proper, 40% in dentate gyrus, 31% in granule cell layer and 18% in pyramidal cell layer. Region size varied at least 50% from largest to smallest measurement. Here we have utilized these differences to identify loci with effects on the dentate gyrus, granule cell layer, hippocampus proper and pyramidal cell layer. Our sample consists of C57BL/6J and DBA/2J and 32 BXD recombinant inbred strains. Volumetric data were corrected for shrinkage and for differences in brain weight. We identified significant loci on chromosomes (Chr) 6, 13 and 15, and a significant interaction locus on proximal Chr 11. A suggestive distal Chr 1 locus overlaps withHipp1a. HipV13a(Chr 13, 42–78 Mb) has an additive effect of 0.56 mm3(12.1%) on dentate gyrus volume, whileGrV6a(Chr 6, 29–65 Mb) has additive effects of 0.14 mm3(16.0%) on the volume of the granule cell layer.HipV13aalso interacts withDGVi11a, a locus on proximal Chr 11 that operates exclusively through its epistatic effect onHipV13aand has no independent main effect.HipV15a(Chr 15, 0–51 Mb) has an additive effect of 1.76 mm3(9.0%) on the volume of the hippocampus proper. We used WebQTL, a recently described web‐based tool, to examine genetic correlation of gene expression with hippocampal volume. We identified a number of genes that map within the QTL intervals and have highly correlated expression patterns. Using WebQTL's extensive database of published BXD phenotypes, we also detected a strong and potentially biologically meaningful correlation between hippocampal volume and the acoustic startle response.