bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of chronic murine and human leptin infusion on plasma leptin and corticosterone levels and energy balance in lean Zucker rats
Authors: Al‐Barazanji K. A. , Buckingham R. E. , Arch J. R. S. , Briscoe C. , Jenkins O. , Tadayyon M. 
Published: March 2003

SUMMARY Aim   To clarify whether centrally delivered leptin can access the circulation and to determine to what extent the effects of i.c.v. h‐leptin and m‐leptin on body weight and plasma corticosterone are due to reduced food intake.Methods   Male lean Zucker rats were infused i.c.v. with recombinant m‐leptin or h‐leptin (42 μg/day) for 7 days. Terminal plasma leptin levels were measured using selective r‐leptin, m‐leptin and h‐leptin RIA. Plasma h‐leptin and corticosterone levels were determined on days 0, 2, 4 and 6 of h‐leptin infusion. Interscapular brown adipose tissue weight and UCP‐1 mRNA expression (an indicator of thermogenic capacity) were also measured.Results   The terminal plasma leptin level was elevated (from 2.2 ± 0.4 to 42.7 ± 20.2 ng/ml) in the h‐leptin‐treated lean rats to levels similar to those in vehicle i.c.v. infused fa/fa rats (72.2 ± 4.7 ng/ml), but this was only detectable when the h‐leptin radioimmunoabsorbent assay (RIA) was used. Further, both m‐leptin and h‐leptin infusions in lean rats elevated terminal plasma corticosterone (352 ± 37 and 389 ± 55 ng/ml, respectively) to levels similar to those in i.c.v. rats (386 ± 62 ng/ml), whereas diet‐restriction by pair‐feeding, with the h‐leptin group, in lean rats had no effect (207 ± 45 ng/ml). The increase in plasma corticosterone level coincided with the maximum hypophagic effects of leptin and preceded the appearance and sustained elevation of exogenous human leptin in the circulation. Both m‐leptin and h‐leptin i.c.v. infusion reduced body weight gain (3% and 4%, respectively, compared to pair‐fed group) and increased UCP‐1 expression (11‐fold and 16‐fold, respectively) in lean rats. However, h‐leptin elicited an earlier effect than m‐leptin on body weight, manifested as an earlier reduction in food intake and greater increase in UCP‐1 expression. h‐Leptin also elicited a greater reduction in body weight gain than did pair‐feeding.Conclusions   Intracerebroventricular‐infused m‐leptin or h‐leptin was detected in the circulation. Furthermore, m‐leptin and h‐leptin elevated plasma corticosterone levels and h‐leptin caused some weight loss in lean rats independently of its suppression of food intake. The elevation of corticosterone levels in the lean rats may be a mechanism whereby they resist excessive weight loss in response to leptin.
Elimination of •O2−/H2O2 by α‐lipoic acid mediates the recovery of basal EDRF/NO availability and the reversal of superoxide dismutase‐induced relaxation in diabetic rat aorta
Authors: Koçak G. , Karasu Ç. 
Published: March 2003

Aim: The aims of this study were to ascertain the mechanism(s) of relaxant action of exogenous superoxide dismutase (SOD) in aortic rings obtained from 12‐week, streptozotocin(STZ)‐diabetic and age‐matched control rats, and to examine the effects of α‐lipoic acid (ALA) treatment (for 6 weeks, after 6 weeks of untreated diabetes) on SOD‐induced relaxations.Materials and Methods: Thoracic aorta rings were suspended to isolated tissue chamber, and the changes in isometric tension were recorded.Results: SOD produced a greater relaxation in untreated‐diabetic rings compared with control rings. ALA treatment partially reversed SOD‐induced relaxation in diabetic aorta. Pretreatment of rings with NG‐nitro‐l‐arginine methyl ester (L‐NAME, 100 µm) inhibited SOD‐induced relaxation. This effect of L‐NAME was markedly observed in control and ALA‐treated‐diabetic rings compared with untreated‐diabetic rings. SOD‐induced relaxation was also inhibited by catalase (60 U/ml) in untreated‐diabetic rings but not in ALA‐treated‐diabetic and control rings. Pretreatment with the cyclooxygenase inhibitor, indomethacin, or the catalase inhibitor, aminotriazole, had no effect on SOD‐induced relaxation in any ring.Conclusion: Findings suggested that: (i) in normal physiological conditions, the relaxant effect of SOD is related to the inhibition of superoxide anion radicals (•O2−)‐induced endothelium‐derived relaxing factor/nitric oxide (EDRF/NO) destruction in the rat aorta; (ii) in diabetic state, excess •O2− increasingly inhibits basal EDRF/NO, and the dismutation of excess •O2− to H2O2 is enhanced by exogenous SOD. H2O2 a vasorelaxant molecule, which probably accounts for the increased responsiveness of diabetic rings to exogenous SOD; and (iii) the reversal effect of in vivo ALA treatment on SOD‐induced relaxation in diabetic aorta is probably linked with the elimination of •O2−/H2O2, which mediates the recovery of basal EDRF/NO availability.
Early vascular abnormalities and de novo nitrate tolerance in diabetes mellitus
Authors: McVeigh G. E. , Morgan D. R. , Allen P. , Trimble M. , Hamilton P. , Dixon L. J. , Silke B. , Hayes J. R. 
Published: March 2003

Objective: The haemodynamic consequence of altered mechanical wall properties in diabetes can impair the compliance characteristics or pulsatile function of arteries before changes in calibre or peripheral resistance become evident. We studied the sensitivity of pulsatile and steady‐state haemodynamic variables in identifying vascular abnormalities and assessing arterial responsiveness to glyceryl trinitrate (GTN) in patients with diabetes, free from clinical complications of the disease.Methods: Radial artery pressure waveforms were recorded in 22 patients with diabetes and 22 age‐ and sex‐matched control subjects, using a calibrated tonometer device. A computer‐based assessment of the diastolic pressure decay was used to quantify changes in arterial waveform morphology in terms of pulsatile (arterial compliance) and steady‐state (peripheral resistance) haemodynamics. Pressure pulse waveforms were recorded before and 3, 6 and 9 min after the administration of 300 µg of GTN.Results: Of the pulsatile and steady‐state impedance parameters, only small artery compliance was significantly different in patients, 4.7 ml/mmHg (95% CI 3.8–5.8), compared with control subjects 7.1 ml/mmHg (95% CI 5.4–8.7); (p < 0.05). In response to GTN small artery compliance increased, and systemic vascular resistance decreased significantly in control subjects; (p < 0.05) but remained unchanged in patients with diabetes.Conclusions: Arterial waveform analysis proved more sensitive in detecting early vascular abnormalities and tracking the haemodynamic effects of GTN in patients with diabetes than changes in total peripheral resistance. The diminished responsiveness of the arterial vasculature to organic nitrates may have therapeutic implications for the treatment of cardiovascular disease in diabetes mellitus.
On the so‐called cavum orbitonasale
Authors: Bjerring Hans C. 
Published: March 2003

AbstractBjerring, H. C. 2000. On the so‐called cavum orbitonasale. —Acta Zoologica (Stockholm) 81: 167–175Defined in the bowfin, Amia calva, the cavitas orbitonasalis (formerly the cavum orbitonasale) lies within the posteromesial part of the ethmoidal region of the endocranium and communicates with the fossa sacci nasalis and the orbita of its own side as well as with the cavitas encephalica endocranii. This intracranial compartment is probably called in being as a result of the pushing forward from the orbita of the points of origin of the ipsilateral oblique eye muscles. Its alleged presence in lizards as a part of the orbita and in mammals as a part of the cavitas encephalica cranii is shown to rest on false premizes. In reality, these two component parts are not homologous, and of all the craniate animals, extant and extinct, some actinopterygian fish alone have cavitates orbitonasales.
Correlation of fluorescence and electron microscopy of F‐actin‐containing sensory cells in the epidermis of Convoluta pulchra (Platyhelminthes: Acoela)
Authors: Pfistermüller R , Tyler S 
Published: March 2003

AbstractPhalloidin‐stained whole mounts of acoel turbellarians show brightly fluorescing club‐shaped structures distributed over the epidermis and concentrated especially at the anterior and posterior tips of the body. By correlating electron micrographic images and fluorescence images of Convoluta pulchra, these structures can be seen to be sensory receptors with a central cilium surrounded by a collar of microvilli. The other candidate for showing fluorescence in the epidermis, namely gland necks, can be ruled out since their distribution is too dense to resemble the distribution of the fluorescent structures seen here. The collared sensory receptors were inserted between epidermal cells, and each bore a central cilium surrounded by a collar of 6–18 microvilli and an additional centrally positioned 2–7 microvilli of which 2 or 3 were associated with a modified rootlet called the swallow’s nest. Confocal scanning laser microscopy resolved the core of actin filaments within the microvilli of the collar and their rootlet‐like connections to the base of the sensory cell. Such receptors could also be identified by fluorescence microscopy in several other species of acoel turbellarians.
Sensory pathways in amphioxus larvae I. Constituent fibres of the rostral and anterodorsal nerves, their targets and evolutionary significance
Authors: Lacalli Thurston C. 
Published: March 2003

AbstractSerial and interval electron micrograph series were used to examine the rostral and anterodorsal nerves of 12.5‐day‐old amphioxus larvae and trace selected fibres to their targets in the nerve cord. The nerves contain a variety of fibre types, including axons from at least two types of epithelial sensory cells and neurites derived from dorsal (Retzius) bipolar cells located within the cord. The rostral epithelial cells form basal synapses with a population of peripheral neurites that probably derive from the dorsal bipolar cells, though other sources are possible. Varicosities containing dense‐core vesicles occur at the tip of the rostrum, indicating the presence of efferent innervation at this site. Within the cord, some peripherally derived rostral afferents terminate at the level of the anterior cerebral vesicle, others synapse directly with both motoneurones and the notochord, but those in the largest bundle target the dendrites of the large paired neurones (LPNs) located in the primary motor centre. LPN dendrites also receive synapses from sensory fibres arriving via the anterodorsal nerves, from the anterior‐most of the dorsal bipolar cells, referred to here as tectal cells, and from a single fibre derived from the frontal eye. This convergence of multiple inputs accords with other evidence that the LPNs are key intermediaries in the sensorimotor pathway that activates the larval escape response. The rostral nerves are much larger at metamorphosis, but the ventral tracts that derive from them are still comparatively small. This is because the majority of rostral fibres are diverted into a late‐developing dorsal tract that travels within the cord to the front end of the dorsolateral neuropile, where most of its fibres disperse and form synapses. The positioning of the dorsal and ventral tracts strongly suggests homology with vertebrate olfactory and terminal nerves, respectively. This, and the question of whether the amphioxus central nervous system has anything comparable to the olfactory bulb, a telencephalic structure, is discussed.
Fine structure of unusual spermatozoa and spermiogenesis of the mite Megisthanus floridanus Banks, 1904 (Acari: Gamasida: Antennophorina)
Authors: Alberti Gerd , Klompen Hans 
Published: March 2003

AbstractThe aflagellate spermatozoa of the gamasid mite Megisthanus floridanus are characterized by a large vacuole which contains a cytoplasmic column protruding into the vacuole from the region defined as the posterior part of the cell. The membrane of the column and the inner membrane of the posterior part of the cytoplasmic mantle (outer sheath) surrounding the vacuole bear numerous so‐called cellular processes. However, most of the outer sheath is reduced and represented solely by a very thin membrane‐like envelope. The posterior part of the cell bears extensive folds. The cell, or, more precisely, the column, shows a deep posterior invagination. This invagination contains extracellular material composed of thin filaments or strands. Peripheral folds emerging from the posterior rim of the cell form a thin‐walled tube that contains the same material as the invagination. The elongated nucleus is attached to a peculiar acrosomal complex consisting of a flat acrosomal cisterna that parallels most of the cell membrane, an attachment cone, and a short acrosomal filament which is embedded in a narrow canal within the nucleus. The spermatozoa of M. floridanus represent a peculiar version of the vacuolated type of sperm known to be plesiomorphic within the anactinotrichid Acari. Some details of spermiogenesis are described and consequences for phylogenetic and systematic considerations are discussed.
Ovicell structure inCallopora dumerilii and C. lineata(Bryozoa: Cheilostomatida)
Authors: Ostrovsky A. N. , Schäfer P. 
Published: March 2003

AbstractAnatomical and SEM‐studies of the brood‐chambers (ovicells) in two bryozoans (Callopora dumeriliiandC. lineata) were undertaken to resolve a long‐term controversy existing in the literature about the origin of the ovicells. In contrast with the interpretation ofSilén (1945), both species investigated possess hyperstomial ovicells with the ooecium formed by the distal (daughter) zooid. The ooecial coelomic cavity communicates with the zooidal coelom through a pore‐like canal or canals remaining after the closure of an arch‐shaped slit. The slit forms during ovicellogenesis. The communication canals are normally plugged by epithelial cells, however incompletely closed canals were also found inCallopora lineata.SEM‐studies of noncleaned, air‐dried specimens showed a relationship between membranous and calcified parts during early ovicellogenesis. It starts from a transverse wall as the calcification of the proximal part of the daughter zooid frontal wall, and has the shape of two flat rounded plates. There are no knobs or any other outgrowths. Conditions and phenomenology of hyperstomial ovicell formation are discussed.
Higher expression of K‐ras is associated with parathyroid hormone‐related protein‐induced hypercalcaemia in renal cell carcinoma
Authors: Kamai T. , Arai K. , Koga F. , Abe H. , Nakanishi K. , Kambara T. , Furuya N. , Tsujii T. , Yoshida K.‐I. 
Published: March 2003

Objectives To determine whether the K‐ras oncogene is associated with parathyroid hormone‐related protein (PTHrP) production in renal cell carcinoma (RCC) and whether the serum value of PTHrP is related to the patients' survival. Patients and methods The serum levels of PTHrP and corrected serum calcium levels were analysed in 51 consecutive patients (29 men and 22 women, mean age 63.7 years, range 33–82) with newly diagnosed RCC. Matched pairs were analysed of the mRNA levels of K‐ras and PTHrP in tumour and in corresponding non‐tumour tissue originating from the same patient, using the polymerase chain reaction after reverse transcription. Results Seven patients had elevated serum PTHrP values at the diagnosis of RCC. The mRNA expression of K‐ras and PTHrP were detected in both tumour and non‐tumour tissues, with K‐ras mRNA levels being higher in the former than the latter (P < 0.05), and correlated with tumour stage (P < 0.05). There were no differences in PTHrP mRNA levels between the tissues. Furthermore, the mRNA levels of K‐ras and PTHrP in seven tumours from patients with high serum values of PTHrP were higher than in tumours from those with normal values (both P < 0.01). The expression of mRNAs of K‐ras and PTHrP was positively correlated (r = 0.771, P < 0.001). In seven patients with high serum PTHrP values the mRNA levels of PTHrP correlated with serum values of PTHrP and calcium (r = 0.875, P < 0.01 and r = 0.762, P < 0.05, respectively). Kaplan‐Meier plots of survival rate in patients with elevated or normal serum PTHrP showed that high serum PTHrP was associated with a shorter overall survival (P < 0.05). The Cox proportional hazards model showed that serum PTHrP was an independent predictor of overall survival (P < 0.05). Conclusions These findings suggest that K‐ras may be associated with PTHrP‐induced hypercalcaemia and that PTHrP levels may reflect the aggressiveness of tumour cells through the K‐ras oncogene in RCC.
Thrombospondin‐1, vascular endothelial growth factor expression and their relationship with p53 status in prostate cancer and benign prostatic hyperplasia
Authors: Kwak C. , Jin R.J. , Lee C. , Park M.S. , Lee S.E. 
Published: March 2003

Objective To evaluate the expression of thrombospondin‐1 (TSP‐1, a potent inhibitor of angiogenesis) and vascular endothelial growth factor (VEGF, an important angiogenic factor in solid tumours) in prostate cancer, and their relationship with p53 status. Patients and methods Using immunohistochemistry, the expression of VEGF, TSP‐1 and p53 was assessed in 82 archival tissue specimens from 23 patients with benign prostatic hyperplasia (BPH), 22 with localized prostate cancer and 37 with metastatic prostate cancer. Seven of the last group had received androgen deprivation therapy. The relationship between the expression of VEGF, TSP‐1 and p53 status was also evaluated with tumour grade and stage in patients with prostate cancer. Results The seven patients receiving hormonal treatment were excluded from the analysis because androgen deprivation significantly increased TSP‐1 and decreased VEGF expression (both P < 0.01). Immunohistochemical analysis showed significantly higher VEGF and significantly lower TSP‐1 expression (both P < 0.01) in prostate cancer than in BPH tissues. There was also significantly higher VEGF and significantly lower TSP‐1 expression (both P < 0.05) in tissues from metastatic than localized prostate cancer. There was no significant correlation between VEGF or TSP‐1 expression and Gleason score, but a significant inverse correlation between TSP‐1 and VEGF expression. There was a significant association between VEGF expression and p53 status (P < 0.05), but TSP‐1 expression was not associated with p53 status. Conclusions Angiogenic factors, including VEGF and TSP‐1, might be important in the development and progression of prostate cancer. These changes seem to be influenced by p53 status. Identifying the angiogenic factors involved in prostate cancer might lead to the development of diagnostic or therapeutic strategies based on anti‐angiogenesis.
Cyclooxygenase‐2: a possible target in schistosoma‐associated bladder cancer
Authors: El‐Sheikh S.S. , Madaan S. , Alhasso A. , Abel P. , Stamp G. , Lalani E.‐N. 
Published: March 2003

Objective To analyse and compare the expression of cyclooxygenase (COX) enzymes in schistosoma‐associated bladder cancer, and to determine any association with tumour grade or stage. Materials and methods Sixty paired samples of tumour and adjacent nonmalignant urothelium were identified. There were 25 squamous and 28 transitional cell carcinomas, and seven adenocarcinomas. Serial sections were obtained and a standard three‐layer immunohistochemistry protocol, using COX‐1‐ and COX‐2‐specific mouse monoclonal antibodies, applied. Results COX‐1 was expressed mostly in nonvascular smooth muscle with weak reactivity in malignant and nonmalignant urothelium. Nonmalignant urothelium expressed COX‐2 weakly, notably in areas of dysplasia and squamous metaplasia whereas there was a significant increase in COX‐2 (P < 0.001) with moderate to strong granular cytoplasmic expression in all three malignant histological types. The COX‐2 reactivity was higher in transitional and adenocarcinomas than in squamous cell carcinoma (P < 0.001). Areas of carcinoma in situ showed COX‐2 reactivity comparable with that in invasive areas and more intense than that detected in dysplastic or metaplastic urothelium (P < 0.001). There was a statistically significant positive correlation between COX‐2 expression and tumour grade (P = 0.0052). Conclusion COX‐2 is over‐expressed in schistosoma‐associated bladder cancer, consistent with a potential role for COX‐2 inhibitors in the prevention and management of this disease.
Free bladder mucosal autograft in the treatment of complicated vesicovaginal fistula
Authors: Sharifi‐Aghdas F. , Ghaderian N. , Payvand A. 
Published: March 2003

Objective To describe an effective and simple method for repairing complicated vesicovaginal fistula using a free bladder mucosal autograft. Patients and methods The study included 14 patients with an iatrogenic vesicovaginal fistula after hysterectomy or prolonged obstructed labour. An initial fistula repair had been attempted in 12 patients. All patients were then repaired using a free bladder mucosal graft technique 3–24 months (mean 8) after the fistula was diagnosed. Results Of the 14 patients 12 had an immediately successful result, with no evidence of leakage, but two required prolonged catheter drainage. Thirteen patients remained dry at the follow‐up 3–15 months later. Two patients had stress urinary incontinence and three patients had urinary tract infection. Conclusions The free bladder mucosal autograft technique is a simple, effective and fast method for vesicovaginal fistula repair. The technique produces an excellent repair of complicated vesicovaginal fistula, and appears to be more physiological and easier to perform than other transabdominal techniques.