bluuebunny/crossref_metadata_2025_split huggingface dataset:
Overnight metabolic fuel deficiency in patients treated conventionally for hypopituitarism
Authors: Al‐Shoumer Kamal A. S. , Ali Kamsiah , Anyaoku Victor , Niththyananthan Ratnam , Johnston Desmond G. 
Published: November 2003

BACKGROUND Hormone replacement in hypopituitary adults attempts to reproduce normal physiology. Conventional regimens fail to mimic normal hormone profiles over 24 hours. OBJECTIVE To investigate the metabolic consequences of conventional hormone replacement in hypopituitary adults by measuring circulating levels of the major fuels, glucose, non‐esterified fatty acids (NEFA), glycerol and 3‐hydroxybutyrate (3‐OHB) over 24 hours in hypopituitary subjects and controls. SUBJECTS Ten GH and adrenocorticotrophin deficient hypopituitary adults on conventional replacement and 13 controls matched for age, sex and body mass index were studied. The patients received replacement with hydrocortisone twice daily (at 0730 and 1730 h; mean (range) daily dose 22 (10–30) mg/24 h) but not with GH. Other hormones were replaced as clinically necessary. MEASUREMENTS Circulating glucose, NEFA, glycerol and 3‐OHB levels were measured over 24 hours together with concentrations of cortisol (total and free), GH and insulin, and urinary free cortisol. RESULTS Levels of glucose, NEFA and 3‐OHB were lower in patients than controls (mean ± SEM) (4.3 ± 0.1 vs 5.3 ± 0.1 mmol/l, P = 0.0001; 291 ± 46 vs 448 ± 48 μmol/l, P = 0.015; 78 ± 8 vs 136 ± 24 μmol/l, P = 0.035, respectively) before breakfast. This decrease in glucose, NEFA and 3‐OHB was observed in the patient group throughout the night, from midnight to breakfast. For NEFA, the decrease persisted throughout the 24 hours. Glycerol did not differ significantly in patients and controls. Integrated levels of total and free plasma cortisol, and 24‐hour urine cortisol excretion, were normal in patients but total and free plasma cortisol concentrations overnight were markedly decreased (overnight area under the curve (AUC) of total cortisol: 440 ± 154 vs 1593 ± 267 nmol/l h, P = 0.0024; overnight AUC of free cortisol: 24 ± 8 vs 161 ± 26 nmol/l h, P = 0.0001). GH levels were low throughout the whole 24 hours in the patient group (24‐hour AUC: 10.6 ± 5.1 vs 74.6 ± 19.6 mU/l h, P = 0.008). CONCLUSIONS Hypopituitary adults on conventional hormone replacement regimens have low concentrations of metabolic fuels, glucose, non‐esterified fatty acids and 3‐hydroxybutyrate throughout the night, possibly related to GH deficiency or to decreased overnight circulating cortisol levels. This overnight fuel deficiency may underlie the mechanism for the non‐specific symptoms, such as fatigue and headache in the early morning, which are frequent in this group of patients.
Cytokine expression in human anterior pituitary adenomas
Authors: Green V. L. , Atkin S. L. , Speirs V. , Jeffreys R. V. , Landolt A. M. , Mathew B. , Hipkin L. , White M. C. 
Published: November 2003

OBJECTIVE There is increasing evidence for the role of cytokines in pituitary differentiated function and tumorigenesis, but the spectrum of cytokines found in the pituitary is unknown. Therefore profiles of cytokine expression were determined in different human anterior pituitary adenoma sub‐types. DESIGN The reverse transcriptase‐linked polymerase chain reaction (PCR) was used to identify the presence of cytokine mRNA within human pituitary adenomas. PATIENTS Seventeen pituitary adenoma biopsies removed at transsphenoidal surgery were examined: 4 somatotrophinomas, 7 non‐functional adenomas, 4 prolactinomas, one case of Cushing’s disease and one case of Nelson's syndrome. MEASUREMENTS RNA was extracted from each adenoma biopsy and reverse transcribed into cDNA. This was specifically amplified in a PCR using oligonucleotide primers complementary to each cytokine. The cytokines investigated were interleukin (IL) ‐lα, IL‐lβ, IL‐2, IL‐4, IL‐5, IL‐6, IL‐7, IL‐8, tumour necrosis factor (TNF)‐α, TNF‐β and transforming growth factor (TGF)‐β1, β2 and β3. The products of each PCR were visualized using agarose gel electrophoresis. RESULTS All 17 adenomas expressed IL‐8 transcripts, but no expression of IL‐2, IL‐5 or IL‐7 was found. IL‐6 was expressed in all 4 somatotrophinomas, 3 of 7 non‐functional tumours, 2 of 4 prolactinomas and in the single case of Nelson's syndrome. At least one of the 3 isoforms of TGF‐β was found in all but 2 tumours; one prolactinoma and one non‐functional adenoma. IL‐1α, IL‐β, IL‐4, TNF‐α and TNF‐β were expressed sporadically by individual adenomas. CONCLUSION These data suggest that whilst IL‐8 may be important, the local expression of the cytokines IL‐2, IL‐5 and IL‐7 is not important in human anterior pituitary tumorigenesis.
Follicle stimulating hormone‐β subunit gene is expressed in parallel with a transcription factor Ad4BP/SF‐1 in human pituitary adenomas
Authors: Ikuyama Shoichiro , Ohe Kenji , Sakai Yoshiyuki , Nakagaki Hiroyuki , Fukushima Takeo , Kato Yukio , Morohashi Ken‐ichirou , Takayanagi Ryoichi , Nawata Hajime 
Published: November 2003

OBJECTIVES A transcription factor Ad4BP/SF‐1 is implicated in the differentiation of gonadotrophs in the pituitary gland, but it is not known whether human pituitary cells express this factor. The present study aimed to disclose (1) whether human pituitary adenomas express Ad4BP/SF‐1, and (2) if this is the case, what kinds of adenoma express the factor. MATERIAL Total RNA was extracted from 23 pituitary adenomas obtained by transsphenoidal surgery, and subjected to Northern blot analyses using cDNAs of bovine Ad4BP/SF‐1, porcine FSH‐β, LH‐β and glycoprotein hormone‐β (GPH‐α) subunits as radiolabelled probes. These adenomas included 13 clinically non‐functioning adenomas, 1 GH/PRL‐producing adenoma, 6 GH‐producing adenomas, 2 PRL‐producing adenomas and 1 ACTH‐producing adenoma. RESULTS The expression of Ad4BP/SF‐1 exactly coincided with the expression of FSH‐β. Thus 5 out of 13 clinically non‐functioning adenomas expressed Ad4BP/SF‐1 and only these 5 adenomas expressed FSH‐β. Interestingly, only one of the GH‐producing adenomas also expressed Ad4BP/SF‐1 as well as FSH‐β. GPH‐α was expressed in 4 non‐functioning adenomas and 2 hormonally functioning adenomas, but did not necessarily coincide with Ad4BP/SF‐1 expression. None of the 23 adenomas we tested expressed LH‐β, probably because LH‐β‐producing adenomas are rather rare. CONCLUSIONS The expression of FSH‐β was parallel with Ad4BP/SF‐1 expression, indicating that the expression of Ad4BP/SF‐1 is restricted to cells derived from gonadotroph lineages in human pituitary adenomas.
Thyroid hypoechogenicity after methimazole withdrawal in Graves' disease: a useful index for predicting recurrence?
Authors: Zingrillo Matteo , D'Aloiso Leonardo , Ghiggi Maria Rosaria , Di Cerbo Alfredo , Chiodini Iacopo , Torlontano Massimo , Liuzzi Antonio 
Published: November 2003

OBJECTIVE A characteristic thyroid ultrasonographic picture with diffuse or scattered low echogenicity has been described in Graves' disease (GD). Thyroid hypoechogenicity in GD at onset has been considered a prognostic index of relapse after medical treatment; moreover, thyroid hypoechogenicity is regularly observed in GD at the onset, but not in patients with ‘burned‐out’ disease. The aim of this study was to evaluate the usefulness of thyroid hypoechogenicity changes in predicting GD relapse. DESIGN Longitudinal prospective study of previously untreated patients with GD. PATIENTS Thirty‐nine consecutive patients aged 10–72 years were treated with methimazole (MMI) for 12–24 months on a titration regimen. Evaluation of patients in remission or with relapse was done 12 and 24 months after MMI withdrawal. MEASUREMENTS Thyroid ultrasonography and TSH receptor antibodies (TRAb) were evaluated in basal conditions and then one month after MMI withdrawal. Thyroid hypoechogenicity score (assessed by the same observer with the same equipment) was graded as: 0 absent; 1 mild; 2 moderate; 3 marked. At the withdrawal evaluation a score < 2 and a TRAb value < 10 U/l were considered as normal. RESULTS Twelve and 24 months after withdrawal, there were 10 (25.6%) and 17 (44.7%) relapses, respectively. Neither thyroid hypoechogenicity score nor TRAb values evaluated in basal conditions, showed significant differences between patients remaining euthyroid and those who became again hyperthyroid. In the whole group, the thyroid hypoechogenicity score was significantly lower at the withdrawal than in basal conditions (1.1±1.1 vs 2±0.8; P < 0.0001); it was significantly lower in patients in remission (P < 0.001), but not in those who relapsed. The thyroid hypoechogenicity score at withdrawal was normal in 23/29 (79.3%) of patients still euthyroid and in 4/10 (40%) of those who relapsed up to the 12th month (P < 0.05); it was normal in 19/21 (90.4%) of patients still euthyroid and in 7/17 (41.2%) of those who relapsed up to the 24th month (P < 0.05). A normal thyroid hypoechogenicity score at withdrawal of MMI had a higher specificity (0.95) and sensitivity (0.59) with respect to TRAb values (0.86 and 0.53, respectively) for the prediction of the relapse of hyperthyroidism at the 24th month. CONCLUSIONS Basal thyroid hypoechogenicity cannot be used as an index of relapse of GD. MMI treatment induces evident changes in thyroid hypoechogenicity, mainly in patients who subsequently go into remission. The absence or a low grade of thyroid hypoechogenicity after MMI treatment seems to be a favourable prognostic index of remission of hyperthyroidism in GD.
The relationship between phytoplankton composition and physical–chemical variables: a comparison of taxonomic and morphological–functional descriptors in six temperate lakes
Authors: DE M Vera Lúcia . Huszar , Nina F. Caraco 
Published: November 2003

Summary1. The relationship between phytoplankton composition and physical–chemical variables was studied in six temperate lakes, characterizing the phytoplankton taxonomically or by a rarely used morphological–functional approach (m/f approach) developed by Reynolds (1997). This approach divides phytoplankton into three groups (C‐, S‐ andR‐strategists) by morphological characters thought to be related to light and nutrient acquisition.2. The lakes ranged from oligotrophic to moderately eutrophic and exhibited both polymictic and dimictic patterns of mixing. Across the trophic gradient total phytoplankton biomass ranged from 0.3 to 4.8 mg (wet weight) L–1 and total phosphorus (TP) from 0.19 to 1.07 μm.3. The taxonomic groups predominantly represented were cyanobacteria, diatoms, dinoflagellates, chrysophytes and chlorophytes. The m/f group that was dominant (> 50% of total biomass) in five of the six lakes was composed of S‐strategists. In four of the six lakes the second most abundant group comprised R‐strategists. In only one lake was biomass dominated by C‐strategists.4. Within‐lake seasonal variations in taxonomic and m/f groups were not predicted well from physical or chemical variables. This lack of predictability is probably caused, in part, by the problem of rapid seasonal variation in environmental conditions as compared to the replacement time of phytoplankton. Considering the data as a whole, however, several physical and chemical variables were significantly related to taxonomic and m/f groups. Some correlations agreed with expectations from the literature and some did not.5. For taxonomic groups, as expected, cyanobacteria were positively associated with temperature, pH and TP and negatively with light and NO3 : TP ratios. Chrysophytes were negatively related to temperature, pH, soluble reactive phosphorus and TP. No other division showed a substantial correspondence to literature expectations.6. For m/f groups: R‐strategists were correlated with high dissolved nutrients (both N and P) and low light; S‐strategists were correlated with low dissolved N. C‐strategists were generally in low abundance in the study lakes, as might be expected from the generally low nutrients in the six lakes. Opposite to expectations, however, their abundance in the study lakes was negatively correlated to dissolved P.7. Despite a lack of complete predictive ability, the m/f approach performed better than the taxonomic approach. This suggests that size and shape of phytoplankton may predict their response to physical and chemical conditions better than taxonomy at the division level.
Phosphorus kinetics of planktonic and benthic assemblages in a shallow subtropical lake
Authors: Hwang Soon‐Jin , Havens Karl E. , Steinman Alan D. 
Published: November 2003

Summary1. Phosphate uptake kinetics and uptake rates were calculated for planktonic (phytoplankton and bacterioplankton) and benthic (epiphyton and epipelon) assemblages in a large, shallow, subtropical lake. Samples were taken bimonthly over the period of 1 year at three different sites to examine spatial and temporal variability in these processes.2. Two of the sites, located at the edge of the littoral zone next to the open water (ecotone sites), had low irradiance at the sediment surface and high total phosphorus (TP) concentration (annual mean TP = 112 μg L–1). The third site, located in the littoral marsh zone, had high irradiance at the sediment surface and low TP concentration (annual mean TP = 7 μg L–1).3. Based on 32P‐PO4 turnover time, P availability varied temporally and spatially. At the two high TP ecotone sites, P concentration was lowest in July and August. At the low TP marsh site, P limited algal production throughout the year.4. The quotient of maximum uptake rate to half saturation constant (Vm/Ks) in the plankton increased by over two orders of magnitude during the P‐limited (summer) period at the two ecotone sites, suggesting that plankton used the scarce phosphorus more efficiently. The specific uptake rate of plankton was significantly greater than that of periphyton at all sites, suggesting that the plankton were more efficient than periphyton at taking up phosphate.5. Periphyton biomass, as well as absolute and percentage P uptake rate, was greater at the marsh site than at the ecotone sites, despite the lower P concentrations in the marsh. This was probably a result of rapid nutrient cycling, combined with high light availability in the marsh.
An acanthocephalan parasite mediates intraguild predation between invasive and native freshwater amphipods (Crustacea)
Authors: Macneil Calum , Fielding Nina J. , Dick Jaimie T. A. , Briffa Mark , Prenter John , Hatcher Melanie J. , Dunn Alison M. 
Published: November 2003

Summary1. The balance of predation between closely related invasive and native species can be an important determinant of the success or failure of biological invasions. In Irish freshwaters, the introduced amphipod Gammarus pulex has replaced the native G. duebeni celticus, possibly through differential mutual intraguild predation (IGP). Theoretically, parasitism could mediate such predation and hence the invasion outcome. However, this idea remains poorly studied.2. In a field survey, we show that the acanthocephalan parasite Echinorynchus truttae is present in more G. pulex populations than G. d. celticus populations. In addition, within parasitised populations, E. truttae is more prevalent in the invader than in the native.3. We show for the first time that an acanthocephalan parasite mediates predation between its intermediate macroinvertebrate hosts. In a field experiment, E. truttae parasitism of the invader lowered IGP upon the unparasitised native. In laboratory experiments, parasitism of G. pulex significantly reduced their predatory impact on recently moulted female G. d. celticus. Parasitism also appeared to cause reduction in predatory behaviour, such as attacks per contact on precopula guarded female natives.4. We conclude that higher parasite prevalence in invaders as compared with natives, by mediation of interspecific interactions, could promote species coexistence, or at least slow species replacements, in this particular biological invasion.
The effect of prey morphology on the feeding behaviour and population growth of the predatory rotifer Asplanchna sieboldi: a case study using five species of Brachionus (Rotifera)
Authors: Nandini S. , Pérez‐Chávez Ricardo , Sarma S. S. S. 
Published: November 2003

Summary1. We investigated the numerical response, functional response and prey preference of Asplanchna sieboldi to five different prey brachionids. We also analysed the feeding behaviour of the predator in terms of encounters, attacks, capture and prey ingested per unit time.2. The five prey species (Brachionus havanaensis, B. rubens, B. patulus, B. macracanthus and B. calyciflorus) differed in their body size and spine length.3. The population growth rates of A. sieboldi ranged from 0.074 ± 0.03 to 0.431 ± 0.02 depending on prey type and density. There was a significant impact of the spine length rather than body size per se on the population growth rates of the predator.4. The maximum number of prey consumed depended on both body size and spine length. In the functional response analyses, the plateau was reached at a prey density of 4–8 ind. mL−1.5. There was a significant impact of prey density on the prey preference of the predator.
Biodiversity and distribution of water mites (Acari, Hydrachnidia) in spring habitats
Authors: Sabatino Antonio Di , Cicolani Bruno , Gerecke Reinhard 
Published: November 2003

Summary1. The distribution, species richness and ecology of spring‐dwelling water mites in Italy were investigated with the aim to better elucidate the role of spring habitats to sustain high levels of biodiversity and their contribution to freshwater biodiversity at a local and regional scale.2. More than 300 springs in different geographic areas (Alps, Central and Southern Apennines, Sicily and Sardinia), were examined with a total of 163 water mite species recorded.3. Species richness in each area ranged from 33 species on Sardinia to 77 on Sicily. The highest diversity was found in the Gran Sasso (Central Apennines). The proportion of crenobionts (species strictly bound to this type of habitat) exceeded 50% in almost all the areas investigated.4. A diverse (up to 20 species per spring) and highly specialised mite fauna was observed in undisturbed rheocrenes and in natural springs of intermediate typology (rheohelocrenes and rheopsammocrenes). In springs subjected to human impacts (pasture, deforestation, alteration and transformation of spring sources) species richness declined and crenobionts were replaced by unspecialised crenoxenes.5. The zoogeographic importance of spring habitats is confirmed by the presence of 18 endemic species and by members of genera with an interesting disjunct and relict distribution.6. A comparison with other geographic areas suggests that springs contain a significant fraction of the total number of species found in freshwater habitats and may contribute almost one third of regional freshwater biodiversity. The presence of endemic crenobionts and rare taxa highlights the importance of these habitats in maintaining high levels of biodiversity as well as their contribution to a better understanding of biodiversity patterns in freshwaters.
Variation in fecundity and other reproductive traits in freshwater mussels
Authors: Haag Wendell R. , Leann Staton J. 
Published: November 2003

Summary1. Life histories of the highly diverse and endangered North American freshwater mussel fauna are poorly known. We investigated reproductive traits of eight riverine mussel species in Alabama and Mississippi, U.S.A.: Amblema plicata, Elliptio arca, Fusconaia cerina, Lampsilis ornata, Obliquaria reflexa, Pleurobema decisum, Quadrula asperata and Q. pustulosa, and compare our results with existing life history information for other species.2. These eight species had reproductive traits characteristic of large, outcrossing populations: hermaphrodites were rare, we found no evidence of protandry, and sex ratios were even or slightly male‐biased.3. Age at sexual maturity varied among species, ranging from <1 to 2 years for L. ornata to 3–9 years for Q. asperata. In all species, most mature females participated in reproduction and fertilisation success was high.5. Fecundity was related positively to both length and age, but length was the best predictor. In six species, fecundity increased exponentially with increasing size; in two species the rate of increase in fecundity declined in larger animals. In four species, fecundity declined in older animals. These latter results indicate weak reproductive senescence; however, in all species, older individuals continued to produce large numbers of offspring. Mean annual fecundity differed widely among species ranging from 9647 to 325 709. Within‐species differences in fecundity were found among rivers and among populations within a river.6. The wide variation in reproductive traits among species indicates the existence of widely divergent life history strategies in freshwater mussels.
Coexistence of cryptic rotifer species: ecological and genetic characterisation of Brachionus plicatilis
Authors: Ortells Raquel , Gómez Africa , Serra Manuel 
Published: November 2003

Summary1. The coexistence of five cryptic species of the rotifer species complex Brachionus plicatilis was investigated in four coastal Mediterranean ponds. Monthly sampling was undertaken for 15 months and species were characterised using allozyme electrophoresis.2. We describe species‐diagnostic allozyme loci that can be used for rapid identification of these species.3. The five species overlapped to some extent in their temporal use of the ponds, although some seasonal segregation was observed.4. The match between temporal and spatial distribution and limnological conditions suggested ecological specialisation in some cases, although we found striking examples of extensive seasonal overlap.5. Our results indicate that sympatry of cryptic rotifer species is largely because of seasonal ecological specialisation, which allows seasonal succession and partitioning of resources. The processes that might be involved in the long periods of overlapping seasonal distributions of species which are potentially competitors are discussed. This example illustrates that the ‘paradox of the plankton’ is more the rule than the exception.
Decreased steroidogenesis and cAMP production in vitro by Leydig cells isolated from rats made hypothyroid during adulthood
Authors: VALENTI S. , GUIDO R. , FAZZUOLI L. , BARRECA A. , GIUSTI M. , GIORDANO G. 
Published: November 2003

The Leydig cell function of adult male rats made hypothyroid with 6‐propyl‐ 2‐thiouracil (6‐PT, 0.1% w/v in drinking water for 1 month) was studied and compared with that of age‐matched controls. After 6‐PT treatment, a slight, non‐significant decrease in serum testosterone was observed, but no changes in testis weight or number of Leydig cells were noted. The in vitro function of Leydig cells was therefore investigated during incubation for 3 h in the presence or absence of several stimuli: LH (30 mIU/mL), forskolin (FK 1 μM), isobutylmethylxanthine (IBMX, 100 μM), GnRH (100 nM) or FK 1 μM + IBMX 100 μM. Irrespective of the stimulus, cells from hypothyroid rats secreted less cyclic AMP, 17‐hydroxyprogesterone, androstenedione and testosterone. No differences in LH receptors were noted between the groups. Prolonged incubation with triiodothyronine (5–250 ng/mL) or thyroxine (5–250 ng/mL) for 3, 16, 24 or 48 h did not affect testosterone secretion in either group; however, administration of IGF‐I (8 ng/mL for 24 h) resulted in increased spontaneous and stimulated testosterone production in both groups. However, when hypothyroid animals were supplemented in vivo with thyroxine a full recovery of Leydig cell function in vitro was noted.In conclusion: (1) Leydig cells from rats made hypothyroid during adulthood produce less testosterone in vitro, both spontaneously and in response to cAMP and non‐cAMP‐mediated stimuli; (2) this is due to a reduction in cAMP production and in the activity of the enzymes in the androgen biosynthetic pathway, and not to changes in LH receptors; (3) direct administration of thyroid hormones did not improve testosterone secretion in either group, while incubation with IGF‐I did.