bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of “Bonnet” Bypass with Radial Artery Interposition Graft in a Patient with Recurrent Cranial Base Carcinoma: Technical Report of Two Cases and Review of the Literature
Authors: Deshmukh Vivek R. , Porter Randall W. , Spetzler Robert F.
Published: February 2005

OBJECTIVE AND IMPORTANCE:

Two patients with recurrent cranial base carcinomas involving the carotid artery received a “bonnet” bypass using the contralateral superficial temporal artery as the donor vessel because the ipsilateral common and external carotid arteries were unavailable. The radial artery was used as the graft.

CLINICAL PRESENTATION:

A 58-year-old man with ear pain and an enlarging mass involving the left cranial base and neck had undergone a right partial glossectomy and modified neck dissection followed by radiotherapy for squamous cell carcinoma. Recurrent carcinoma extensively involved the left internal carotid artery. A 46-year-old man with jaw pain and hoarseness had undergone multiple resections and radiation therapy for medullary thyroid carcinoma. Magnetic resonance imaging showed recurrent tumor on the right.

INTERVENTION:

Both patients underwent a pterional craniotomy. The supraclinoid internal carotid artery was exposed. The radial artery was harvested. The contralateral superficial temporal artery was dissected at its bifurcation into the frontal and parietal branches. The radial artery graft was anastomosed to the superficial temporal artery and a recipient ipsilateral branch of the middle cerebral artery. The internal carotid artery was clip-ligated. After surgery, both patients remained neurologically stable. Angiography confirmed that the bypasses were patent and that the middle cerebral artery territory filled. The patients’ carcinomas were resected aggressively.

CONCLUSION:

When aggressive resection of cranial base tumors is needed and the ipsilateral carotid artery is unavailable as a donor vessel, a “bonnet” bypass with carotid artery sacrifice may be performed. Compared with vein grafts, microsurgical anastomosis is easier and the patency rate is higher with a radial artery graft.
Titanium Cage-assisted Polymethylmethacrylate Reconstruction for Cervical Spinal Metastasis: Technical Note
Authors: Liu James K. , Rosenberg William S. , Schmidt Meic H.
Published: February 2005

OBJECTIVE:

Reconstruction and stabilization of the cervical spine after vertebrectomy is an important goal in the surgical management of spinal metastasis. The authors describe their reconstruction technique using a titanium cage-Silastic tube construct injected with polymethylmethacrylate (PMMA) augmented by an anterior cervical plate. The surgical results using this technique are reviewed.

METHODS:

Six patients ranging from 43 to 70 years of age underwent resection of metastatic tumor in the cervical spine followed by cage-assisted PMMA reconstruction of the anterior spinal column. The following reconstruction technique was performed. A Silastic tube is incised longitudinally and placed circumferentially around a titanium cage with the opening facing anteriorly. The cage-Silastic tube construct is carefully tapped into the corpectomy defect and filled with PMMA. The final construct is then augmented with anterior cervical plate fixation.

RESULTS:

Two patients required additional posterior stabilization with lateral mass screws and rods. All patients achieved immediate stabilization, restoration of vertebral body height and normal lordosis, and preservation of the ability to walk independently. Five patients experienced significant palliation of biomechanical neck pain. There were no complications of neurological worsening, postoperative hematoma, wound infection, subsidence, graft dislodgement, or construct failure during a follow-up period of 1 to 19 months (mean, 6.8 mo).

CONCLUSION:

Titanium cage-assisted PMMA reconstruction augmented with an anterior cervical plate is an effective means of reconstruction after tumor resection in patients with cervical spinal metastasis. The Silastic tube holds the PMMA within the cage and protects the spinal cord from potential thermal injury.
Lateral Ventricle Tumors: Surgical Strategies According to Tumor Origin and Development— A Series of 72 Cases
Authors: D'Angelo Vincenzo A. , Galarza Marcelo , Catapano Domenico , Monte Vincenzo , Bisceglia Michele , Carosi Illuminato
Published: February 2005

OBJECTIVE:

Optimal surgical management in lateral ventricle tumors remains controversial. We conducted a retrospective study of patients with these lesions treated with a surgical strategy on the basis of tumor origin: primary or secondary ventricular and associated transependymal development.

METHODS:

A total of 72 patients underwent surgery for lateral ventricle tumors. The mean patient age was 39 years (range, 6 mo to 78 yr). Raised intracranial pressure occurred in 53% of patients, followed by mental disturbances or psychiatric symptoms (32%) and motor deficits (21%). The transcortical approach was used in 44 patients, and an interhemispheric approach was used in 28 patients; a transcallosal approach was used in 16 patients, and a parasplenial approach was used in 12 patients. Neuropsychological tests were performed in selected patients.

RESULTS:

Total resection was performed in 82% of patients. Sixty-five percent of tumors were benign and low-grade tumors. There was no surgical mortality, and the morbidity rate was 11%. Postoperative epilepsy (5.9%) was significantly increased in the transcortical group. The mean follow-up period was 55 months; 59% of patients achieved good recovery and moderate disability. In postoperative neuropsychological testing sessions, deficits in verbal memory were observed in six patients (8%). Final morbidity correlated well with preoperative clinical condition and pathological diagnosis.

CONCLUSION:

Lateral ventricle tumors can be treated best by careful selection of the approach according to tumor origin and development. Overall, the transcallosal approach is preferred, but in patients with transependymal growth or large primary or secondary ventricular tumors, the transcortical is a better option.
Biomechanical Comparison of Two Stabilization Techniques of the Atlantoaxial Joints: Transarticular Screw Fixation versus Screw and Rod Fixation
Authors: Kuroki Hiroshi , Rengachary Setti S. , Goel Vijay K. , Holekamp Scott A. , Pitkänen Ville , Ebraheim Nabil A.
Published: February 2005

OBJECTIVE:

To compare the biomechanical stability imparted to the C1 and C2 vertebrae by either transarticular screw fixation (TSF) or screw and rod fixation (SRF) techniques in a cadaver model.

METHODS:

Ten fresh ligamentous human cervical spine specimens were harvested from cadavers. The specimens were tested sequentially in the intact state, after injury and stabilization (unilateral left side and bilateral), and after fatiguing to 5000 cycles (0.5 Hz) at ±1.0 N·m of flexion and extension. The specimens were stabilized by use of TSF in 5 spines or SRF in the other 5 spines. The data were converted to angular displacements, and the stabilized cases were compared with intact states for evaluating the efficacies of the two techniques in stabilizing the C1–C2 segments.

RESULTS:

In the TSF group, the unilateral fixation using one screw imparted a significant stability in only the axial rotation mode. The unilateral procedure in the SRF group was effective in stabilization in all modes except in extension. The bilateral procedure in both of the groups was effective across the C1–C2 segment. However, the SRF group afforded higher stability than the corresponding TSF group in the flexion and extension modes. The degree of stability did not change after fatigue compared with the prefatigue data.

CONCLUSION:

In general, a surgeon should undertake a bilateral fixation to achieve sufficient stability across the atlantoaxial complex, and either technique will provide satisfactory results, although the SRF technique may be better in the flexion and extension modes. One should use the SRF procedure while trying to achieve stability with a unilateral system.
Bulbar Compression by an Ectatic Vertebral Artery: A Novel Neurovascular Construct Relieved by Microsurgical Decompression
Authors: Tomasello Francesco , Alafaci Concetta , Salpietro Francesco M. , Longo Marcello
Published: February 2005

OBJECTIVE:

Brainstem compression caused by vascular abnormalities has rarely been reported in the literature. We describe five cases of large ectatic vertebral artery causing compression and distortion of the medulla oblongata with pyramidal tract signs and low cranial nerve dysfunction. Microvascular decompression by retracting the vertebral artery and anchoring it to the dura has been the treatment of choice.

METHODS:

Five patients, four male and one female, presented with progressive myelopathic features and lower cranial nerve dysfunction, especially dysphonia and dysphagia. Four patients were affected by systemic arterial hypertension. Magnetic resonance imaging showed impingement of the right vertebral artery in three patients and the left vertebral artery in two patients, on the right and left lateral medulla, respectively. In two patients, hypoplasia of the contralateral vertebral artery was documented.

RESULTS:

All patients underwent neurovascular decompression of the medulla oblongata. The ectatic and tortuous vertebral artery was detached from the medulla, shifted away, and repositioned by anchoring to the nearby dura mater using a Gore-Tex vascular slip. Postoperatively, all patients but one had improvement of their previous neurological symptoms.

CONCLUSION:

Brainstem dysfunction caused by a tortuous ectatic vertebral artery might be less uncommon than expected. It should be considered a new distinct clinical entity, the real incidence of which needs to be carefully evaluated by an appropriate diagnostic protocol, which includes primarily magnetic resonance imaging with specific three-dimensional sequences. Awareness of this condition is necessary to ensure the appropriate treatment. Surgical microvascular decompression seems very effective.
Landmarks for Vertebral Artery Repositioning in Bulbar Compression Syndrome: Anatomic and Microsurgical Nuances
Authors: Grasso Giovanni , Alafaci Concetta , Passalacqua Marcello , Tschabitscher Manfred , Salpietro Francesco M. , Tomasello Francesco
Published: February 2005

OBJECTIVE:

The purpose of this study was to better elucidate the anatomic relationship between the vertebral artery (VA) along with its perforating vessels and the brainstem to develop anatomic guidelines that would be helpful when decompressing medulla oblongata compressed by the VA.

METHODS:

Microanatomy dissection was performed in six formalin-fixed cadaveric heads. The VA, posteroinferior cerebellar artery (PICA), anteroinferior cerebellar artery (AICA), and lower brainstem perforators were examined under magnification using a surgical microscope. The outer diameters of the VA, PICA, and AICA were measured. The distance between the VA, lying within the lateral cerebellomedullary cistern, and the medulla oblongata was quantified. The lower brainstem perforating vessels were examined in relation to their course, outer diameter, and length.

RESULTS:

In four of six brains, the left VA was dominant, presenting an outer diameter at least 0.8 mm larger than the contralateral VA. The average distance between the VA and the medulla oblongata was 3 mm. The perforating branches presented a mean outer diameter of 0.7 mm. In particular, perforators arising from the VA and PICA (Groups 1 and 2) presented an average outer diameter of 0.2 mm and an average length of 7 mm. Perforating vessels arising from the AICA and vertebrobasilar junction (Groups 3 and 4) presented an average outer diameter of 0.4 mm and an average length of 12 mm.

CONCLUSION:

This work provides new information that may be useful to minimize the risk of injury of perforators when operating on medulla oblongata compression by the VA.
Evidence for the use of reflected self-generated seismic waves for spatial orientation in a blind subterranean mammal
Authors: Kimchi Tali , Reshef Moshe , Terkel Joseph
Published: February 2005

Subterranean mammals like the blind mole-rat (Rodentia: Spalax ehrenbergi) are functionally blind and possess poor auditory sensitivity,limited to low-frequency sounds. Nevertheless, the mole-rat demonstrates extremely efficient ability to orient spatially. A previous field study has revealed that the mole-rat can assess the location, size and density of an underground obstacle, and accordingly excavates the most efficient bypass tunnel to detour around the obstacles. In the present study we used a multidisciplinary approach to examine the possibility that the mole-rat estimates the location and physical properties of underground obstacles using reflected self-generated seismic waves (seismic `echolocation').

Our field observations revealed that all the monitored mole-rats produced low-frequency seismic waves (250-300 Hz) at intervals of 8±5 s (range:1-13 s) between head drums while digging a bypass to detour an obstacle. Using a computerized simulation model we demonstrated that it is possible for the mole-rat to determine its distance from an obstacle boundary (open ditch or stone) by evaluating the amplitude (intensity) of the seismic wave reflected back to it from the obstacle interface. By evaluating the polarity of the reflected wave the mole-rat could distinguish between air space and solid obstacles. Further, the model showed that the diffracted waves from the obstacle's corners could give the mole-rat precise information on the obstacle size and its relative spatial position.

In a behavioural experiment using a special T-maze setup, we tested whether the mole-rat can perceive seismic waves through the somatosensory system and localize the source. The results revealed that the mole-rat is able to detect low frequency seismic waves using only its paws, and in most cases the mole-rats determined accurately the direction of the vibratory source. In a histological examination of the glabrous skin of the mole-rat's paws we identified lamellate corpuscle mechanoreceptors that might be used to detect low frequency seismic waves.

The combined findings from these different approaches lead us to suggest that a specialized seismic `echolocation' system could be used by subterranean mammals to determine the most energy-conserving strategy with which to bypass an obstacle, as well as to estimate their distance from the surface, keeping their tunnels at the optimal depth.
Host nutrition determines blood nutrient composition and mediates parasite developmental success:Manduca sextaL. parasitized byCotesia congregata(Say)
Authors: Thompson S. N. , Redak R. A. , Wang L.-W.
Published: February 2005

This investigation examined the influence of dietary protein and carbohydrate balance in a chemically defined artificial diet for Manduca sexta larvae on development of the gregarious parasite Cotesia congregata. Normal unparasitized larvae and larvae superparasitized in the fourth stadium were reared to the end of the fifth stadium on six diets,each having the same total amount of casein and sucrose but with different ratios ranging from high protein/no carbohydrate through to low protein/high carbohydrate. Levels of blood protein nitrogen and trehalose, nutrients supporting growth and development of C. congregata, varied with diet and were influenced by parasitism. Different levels of blood metabolites reflected differences in diet consumption, and the relationships between protein nitrogen and trehalose were very similar to those for protein and carbohydrate intake by parasitized and normal larvae on various diets. Dietary nutrient ratio had a significant effect on parasite burden, the numbers of parasites developing in individual host larvae and on parasite biomass. Parasites included individuals that developed and eventually emerged as second instar larvae, moulted to third instars and pupated. Many apparently mature second instar parasites, however, failed to emerge. The proportion of non-emerging individuals varied with diet, and in some cases, parasites failing to emerge were greater in number and total biomass than those that did emerge to complete development. On most diets, the mass of individual parasites was similar regardless of dietary nutrient ratio. Three dimensional models developed to demonstrate the relationships between blood protein nitrogen and trehalose levels and parasite burden and biomass established that the levels of both metabolites are important for supporting growth and development of emerged and non-emerged parasites. In the case of emerged parasites, however, the relationships are linear, and a quadratic function best describes the relationships with non-emerged parasites. Blood metabolite levels supporting the greatest parasite burden and biomass of emerged and non-emerged parasites occupy a region of two dimensional space corresponding to approximately 60-200 mg per insect of protein nitrogen and 60-100 mg per insect of trehalose. Despite the differences in the response of emerged and non-emerged parasites to host nutrition, the present results indicate that host nutrition is not the critical factor determining parasite emergence. The significance of these findings to the biology of C. congregata is discussed.
Analysis of Na+, Cl-, K+, H+and NH4+ concentration gradients adjacent to the surface of anal papillae of the mosquitoAedes aegypti: application of self-referencing ion-selective microelectrodes
Authors: Donini Andrew , O'Donnell Michael J.
Published: February 2005

Ion concentration gradients adjacent to the surface of the anal papillae of larvae of the mosquito Aedes aegypti were measured using self-referencing ion-selective microelectrodes. The gradients were used to calculate estimates of ion fluxes into and out of the papillae. There was a net influx of Na+, Cl- and K+ from the bathing medium and a net efflux of acid and NH4+. No Ca2+ gradients were detectable. Na+ and Cl-influx occurred against a concentration gradient suggesting active transport. Although Na+, Cl- and NH4+gradients were uniform along the length of the papillae, the proximal regions of the papillae in vivo revealed significantly higher H+and K+ gradients compared with distal regions. The calculated ion fluxes at the papillae are sufficient for complete Na+,K+ and Cl- haemolymph replacement in ∼4 h with external ion concentrations of 5 mmol l-1. Ion gradients were also detected adjacent to the surface of isolated papillae; however, Na+and H+ gradients were higher, and Cl- gradients were lower relative to papillae in vivo. The results support previous findings that the anal papillae of mosquito larvae are important structures for ion regulation, and suggest that these structures may be used for the excretion of nitrogenous waste.
The early life history of tissue oxygenation in crustaceans: the strategy of the myodocopid ostracodCylindroleberis mariae
Authors: Corbari Laure , Carbonel Pierre , Massabuau Jean-Charles
Published: February 2005

We studied basic principles of respiratory physiology in Cylindroleberididae, Cylindroleberis mariae Baird 1850,which are millimetre-sized crustaceans (myodocop ostracod) having a fossil record dating back to about 425 millions years ago. Facing experimental changes of O2 partial pressures in the range 2-40 kPa (normoxia is 21 kPa), C. mariae lack any regulatory mechanism to adapt their ventilatory and circulatory activity. Thus, the oxygenation status of their internal milieu must follow, as a dependant variable, the ambient oxygenation. Freely behaving C. mariae exhibit a marked diurnal activity rhythm. They are actively swimming in the water column during night, where they inspire in normoxic-normocapnic water. They are resting in self-made nests during daytime, where they are rebreathing in a confined and hypoxic environment. By analogy to extensive previous literature data, we suggest that these changes of respiratory gas content, and the associated tissue gas status, participate to the shaping of their metabolic activity and behaviour. To conclude, as Cylindroleberididae are early crustaceans exhibiting a remarkable stasis since the Palaeozoic, present data illustrates how principles of tissue oxygenation strategy can cover an impressive time scale.
Arginine kinase in the demosponge Suberites domuncula:regulation of its expression and catalytic activity by silicic acid
Authors: Perović-Ottstadt Sanja , Wiens Matthias , Schröder Heinz-C. , Batel Renato , Giovine Marco , Krasko Anatoli , Müller Isabel M. , Müller Werner E. G.
Published: February 2005

In Demospongiae (phylum Porifera) the formation of the siliceous skeleton,composed of spicules, is an energetically expensive reaction. The present study demonstrates that primmorphs from the demosponge Suberites domuncula express the gene for arginine kinase after exposure to exogenous silicic acid. The deduced sponge arginine kinase sequence displays the two characteristic domains of the ATP:guanido phosphotransferases; it can be grouped to the `usual' mono-domain 40 kDa guanidino kinases (arginine kinases). Phylogenetic studies indicate that the metazoan guanidino kinases evolved from this ancestral sponge enzyme; among them are also the `unusual'two-domain 80 kDa guanidino kinases. The high expression level of the arginine kinase gene was already measurable 1 day after addition of silicic acid by northern blot, as well as by in situ hybridization analysis. Parallel determinations of enzyme activity confirmed that high levels of arginine kinase are present in primmorphs that had been exposed for 1-5 days to silicic acid. Finally, transmission electron-microscopical studies showed that primmorphs containing high levels of arginine kinase also produce siliceous spicules. These data highlight that silicic acid is an inorganic morphogenetic factor that induces the expression of the arginine kinase, which in turn probably catalyzes the reversible transfer of high-energy phosphoryl groups.
Associative learning of plant odorants activating the same or different receptor neurones in the moth Heliothis virescens
Authors: Skiri H. T. , Stranden M. , Sandoz J. C. , Menzel R. , Mustaparta H.
Published: February 2005

The importance of olfactory learning in host plant selection is well demonstrated in insects, including the heliothine moths. In the present study olfactory conditioning of the proboscis extension response was performed to determine the moths' ability to learn and discriminate three plant odorants:β-ocimene and β-myrcene (activating the same receptor neurone type),and racemic linalool (activating two different types). The conditioned stimulus (CS) was an air puff with each odorant blown into a constant air stream and over the antennae, and the unconditioned stimulus (US)was sucrose solution applied first to the antennal taste sensilla, then to the proboscis. Conditioning with increasing odorant concentrations induced increased learning performance. The concentration threshold for learning was 100 times lower for racemic linalool than for the two other odorants,a fact that can be correlated with a higher sensitivity of the moths' antennae to racemic linalool as shown in electroantennogram recordings. After correcting for the different odour sensitivities, the moths' ability to discriminate the odorants was studied. Differential conditioning experiments were carried out, in which moths had to distinguish between a rewarded (CS+)odorant and an explicitly unrewarded odorant (CS-), choosing odour concentrations giving the same learning rate in previous experiments. The best discrimination was found with β-myrcene as the rewarded odorant and racemic linalool as the unrewarded. The opposite combination gave lower discrimination, indicating a higher salience for β-myrcene than for racemic linalool. The moths could also discriminate betweenβ-ocimene and β-myrcene, which was surprising, since they activate the same receptor neurone type. No difference in salience was found between these two odorants.
Hypotonicity induced K+ and anion conductive pathways activation in eel intestinal epithelium
Authors: Lionetto M. G. , Giordano M. E. , De Nuccio F. , Nicolardi G. , Hoffmann E. K. , Schettino T.
Published: February 2005

Control of cell volume is a fundamental and highly conserved physiological mechanism, essential for survival under varying environmental and metabolic conditions. Epithelia (such as intestine, renal tubule, gallbladder and gills)are tissues physiologically exposed to osmotic stress. Therefore, the activation of `emergency' systems of rapid cell volume regulation is fundamental in their physiology. The aim of the present work was to study the physiological response to hypotonic stress in a salt-transporting epithelium,the intestine of the euryhaline teleost Anguilla anguilla. Eel intestinal epithelium, when symmetrically bathed with Ringer solution,develops a net Cl- current giving rise to a negative transepithelial potential at the basolateral side of the epithelium.

The eel intestinal epithelium responded to a hypotonic challenge with a biphasic decrease in the transepithelial voltage (Vte) and the short circuit current (Isc). This electrophysiological response correlated with a regulatory volume decrease (RVD) response, recorded by morphometrical measurement of the epithelium height. Changes in the transepithelial resistance were also observed following the hypotonicity exposure.

The electrogenic Vte and Iscresponses to hypotonicity resulted from the activation of different K+ and anion conductive pathways on the apical and basolateral membranes of the epithelium: (a) iberiotoxin-sensitive K+ channels on the apical and basolateral membrane, (b) apamin-sensitive K+channels mainly on the basolateral membrane, (c) DIDS-sensitive anion channels on the apical membrane. The functional integrity of the basal Cl-conductive pathway on the basolateral membrane is also required.

The electrophysiological response to hypotonic stress was completely abolished by Ca2+ removal from the Ringer perfusing solution, but was not affected by depletion of intracellular Ca2+ stores by thapsigargin.
Effects of physiological state, mass change and diet on plasma metabolite profiles in the western sandpiperCalidris mauri
Authors: Seaman D. A. , Guglielmo C. G. , Williams T. D.
Published: February 2005

We used a food restriction/refeeding protocol to put birds through a controlled cycle of mass loss and mass gain to investigate the effects of rate and phase of mass change on plasma metabolite levels in relation to diet. Despite marked differences in fat content of the two diets (18% vs4%) mean rate of mass loss or mass gain was independent of diet. There was also no effect of diet on plasma levels of any of the four measured metabolite(triglyceride, glycerol, uric acid and β-OH-butyrate) during mass loss. However, during mass gain birds on the low fat diet had higher plasma levels of triglyceride and uric acid and lower β-OH-butyrate than birds gaining mass on the high-fat diet. Thus, diet composition can affect plasma metabolite profiles independently of differences in rates of mass change. Nevertheless,certain plasma metabolites were related to variation in rates of mass change across physiological states. Glycerol levels were negatively related to the rate of mass change (independent of diet), and butyrate was negatively related to the rate of mass change on both diets (though the slope of this relationship was diet dependent). Uric acid was positively related to the rate of mass change but only for birds on the low-fat diet. Our study therefore confirms that measurement of plasma metabolites can provide robust information on physiological state (gain, loss) and the rate of mass change (e.g. in free-living birds caught only once) although researchers should be cogniscent of potential confounding effects of diet composition for certain metabolites,both for field studies and for future experimental validations of this technique.
Eyeshine and spectral tuning of long wavelength-sensitive rhodopsins: no evidence for red-sensitive photoreceptors among five Nymphalini butterfly species
Authors: Briscoe Adriana D. , Bernard Gary D.
Published: February 2005

Spectral tuning of rhodopsins commonly refers to the effects of opsin amino acid substitutions on the wavelength for peak sensitivity of the rhodopsin absorption spectrum. Nymphalini butterflies provide an opportunity for identifying some of the amino acid substitutions responsible for insect rhodopsin spectral tuning because the majority of photoreceptor cells (R3-9)in the adult retina express only a single long wavelength-sensitive (LWS)opsin mRNA transcript. Therefore, the opsin genotype can be directly correlated with its phenotype. We determined the LWS opsin gene sequence from cDNA of the mourning cloak Nymphalis antiopa, and from genomic DNA of the malachite Siproeta stelenes and the peacock Inachis io.Using an epi-microspectrophotometer we examined each butterfly's eyeshine for photochemical evidence of multiple LWS rhodopsins and found only one. We then performed partial-bleaching experiments to obtain absorbance spectra for the LWS rhodopsins of all three species as well as from another nymphalid, the buckeye Junonia coenia. The isolated LWS opsin gene sequences varied in length from 1437-1612 bp and encode rhodopsins R522 (S. stelenes),R530 (I. io), R534 (N. antiopa) and, together with a previously published sequence, R510 (J. coenia). Comparative sequence analysis indicates that the S. stelenes rhodopsin is slightly blue-shifted compared to the typical 530 nm lepidopteran rhodopsin because of the presence of a S138A substitution at a homologous site that in mammalian MWS/LWS rhodopsins causes a 5 nm blue-shift. The difference in peak absorption between R522 of S. stelenes and R530 of Inachis io is therefore largely accounted for by this substitution. This suggests that spectral tuning mechanisms employing the S138A may have evolved in parallel in mammalian and butterfly MWS/LWS rhodopsins across 500 million years of evolution.
Challenges and intriguing problems in comparative renal physiology
Authors: Dantzler William H.
Published: February 2005

The comparative approach has proved important many times in understanding renal function and continues to offer possible approaches to unsolved problems today, in three general areas.

Quantification of glomerular ultrafiltration. In contrast to the complex capillary network in the mammalian glomerulus, the glomerulus of the superficial loopless (reptilian-type) avian nephrons consists of a single capillary loop. This structure, in an avian species where it can be approached directly, should for the first time permit accurate determinations of the pressure profiles and the capillary area involved in glomerular ultrafiltration in an animal with high arterial pressure. Fluid reabsorption by proximal renal tubules. In some reptilian proximal renal tubules, isolated and perfused in vitro, isosmotic fluid reabsorption can occur at control rates when lithium replaces sodium or when some other substance replaces sodium or chloride or both in the perfusate and bathing medium simultaneously. Reabsorption at the control rates, regardless of the composition of the perfusate and bathing medium, can be at least partially inhibited by cold and cyanide, but not by blockers of Na+-K+-ATPase. It is also independent of the buffer system used, but it is reduced about 20% by removal of colloid from the peritubular fluid. During the substitutions, the surface area of the proximal tubule cells increases dramatically and might permit some insignificant force to be more effective in the reabsorptive process. Understanding the process involved in this, apparently unique coupling of solute and fluid transport,certainly would be very valuable in understanding coupled transport of solutes and water across epithelia in general. Urate secretion by proximal renal tubules. Urate is the major excretory end product of nitrogen metabolism in birds, most reptiles, and a few amphibians. It undergoes net secretion by the renal tubules. It has been possible to learn much about the physiology of net secretion in reptiles and birds and this process appears to be similar to the much less significant secretory flux in some mammals. However, nothing is known about the molecular basis of the transport system and understanding these processes may provide important information for mammals as well as reptiles and birds. These are some examples of intriguing possibilities for comparative studies of renal physiology.
Olfactory learning by means of trophallaxis inApis mellifera
Authors: Gil Mariana , De Marco Rodrigo J.
Published: February 2005

Early reports indicate that trophallaxis, i.e. the exchange of liquid food by mouth, may allow honeybees to assign nectar odours with predictive values to anticipate biological meaningful reward stimuli. Nevertheless, this type of learning has not been addressed directly. In the present study, pairs of animals were isolated to induce trophallaxis under controlled conditions and,afterwards, the honeybee proboscis extension reflex was used to investigate the possible role of trophallaxis in learning olfactory cues. The results demonstrate unambiguously that associative learning actually occurs by means of trophallaxis. Animals associate the odour (as the conditioned stimulus or CS) and the sucrose (as the unconditioned stimulus or US) present in the solution they receive through trophallaxis. Moreover, this particular kind of learning leads to long-term olfactory memories after a single learning trial,even when trophallaxis is brief. In addition, we found that the strength of association is clearly affected by CS and US intensity as well as the recent previous foraging experiences of the animals. Comparisons are presented among several features of the learning during trophallaxis and the classical conditioning of the proboscis extension reflex with restrained subjects. Finally, the relevance of learning through trophallaxis in the task of successful foraging is discussed.
Thyroglobulin Antibodies in Serum of Patients with Differentiated Thyroid Cancer: Relationship between Epitope Specificities and Thyroglobulin Recovery
Authors: Okosieme Onyebuchi E , Evans Carol , Moss Laura , Parkes Arthur B , Premawardhana LD Kuvera E , Lazarus John H
Published: February 2005

Background: Serum antibodies against thyroglobulin (TgAbs) are common in patients with differentiated thyroid cancer (DTC) and can interfere in thyroglobulin (Tg) assays. We identified the epitopes on Tg recognized by TgAb-positive sera from patients with DTC and examined the association between epitope specificity patterns and Tg recovery.

Methods: We tested 50 DTC sera for Tg epitope specificity, TgAbs, and Tg recovery. Epitope recognition was determined by use of a panel of 10 well-characterized Tg monoclonal antibodies directed against 6 Tg antigenic clusters (I–VI) in competitive reactions with test sera. Tg was measured by the Thyroglobuline IRMA (CIS bio international). Recovery of added Tg (TgREC) was determined by an in-house assay.

Results: Epitope recognition was restricted to immunodominant clusters in 58% of patients, whereas the rest were either broadly heterogeneous (16%) or nonreactive (26%). Median Tg recovery did not differ between sera with restricted and unrestricted specificities (69% vs 80%; P >0.05). TgREC was inversely correlated with the total number of epitopes recognized by sera (r = −0.66; P <0.001).

Conclusions: TgAbs with both restricted and broad specificities are present in patients with DTC. TgAb interference is related to the number of epitopes recognized by sera rather than the pattern of epitope recognition.
Analysis of T-Cell Receptor Vβ Gene Repertoires after Immune Stimulation and in Malignancy by Use of Padlock Probes and Microarrays
Authors: Banér Johan , Marits Per , Nilsson Mats , Winqvist Ola , Landegren Ulf
Published: February 2005

Background: Detection of expanded T-cell clones, identified by their receptor (TCR) repertoires, can assist diagnosis and guide therapy in infectious, inflammatory, and autoimmune conditions as well as in tumor immunotherapy. Analysis of tumor-infiltrating lymphocytes often reveals preferential use of one or a few TCR Vβ genes, compared with peripheral blood, indicative of a clonal response against tumor antigens.

Methods: To simultaneously measure the relative expression of all Vβ gene families, we combined highly specific and sensitive oligonucleotide reagents, called padlock probes, with a microarray read-out format. T-Cell cDNA was combined with a pool of Vβ subfamily-specific padlock probes. Reacted probes were selectively amplified and the products hybridized to a microarray, from which the Vβ subfamily distribution in each sample could be determined relative to a control sample.

Results: In lymphocytes stimulated with the superantigen staphylococcal enterotoxin B, we detected expansions at the mRNA level of TCR subfamilies previously shown to respond to staphylococcal enterotoxin B. Expansions of the same Vβ families could also be detected by flow cytometry. In samples from two bladder cancer patients, we detected predominant representations of specific Vβ subfamilies in both tumor-infiltrating lymphocytes and in the draining lymph nodes, but not in non-tumor-draining lymph nodes or peripheral blood. Several expression profiles from draining lymph nodes in patients with malignant melanoma were divergent from profiles seen in non-tumor-draining lymph nodes.

Conclusion: Padlock probe-based parallel analysis of TCR Vβ gene distributions provides an efficient method for screening multiple samples for T-cell clonal expansions with reduced labor and time of analysis compared with traditional methods.
The structure of the juvenile hormone binding protein gene from Galleria mellonella
Authors: Sok Agnieszka J. , Czajewska Kamila , Ożyhar Andrzej , Kochman Marian
Published: February 2005

Juvenile hormone (JH) and ecdysone are the key hormones controlling insect growth and development. The juvenile hormone binding protein (JHBP) is the first member in the array of proteins participating in JH signal transmission. In the present report a wholejhbpgene sequence (9790 bp) is described. Thejhbpgene contains four introns (A–D). All the introns have common flanking sequences: GT at the 5′ and AG at the 3′ end. The first intron is in phase 1, the second in phase 2, and the third and fourth in phase 1. An analysis of these sequences suggests that U2-class spliceosomes are involved in intron excision from pre-mRNA. Several horizontally transmitted elements from other genes were found in the introns. Alljhbpexons are positioned in local AT-reach regions of the gene. A search for core promoter regulatory elements revealed that the TATA box starts 29 bp preceding the start of transcription; the sequence TCAGTA representing a putative initiator sequence (Inr) starts at position +14. Eight characteristic sequences for bindingBroad-Complexgene products, which coordinate the ecdysone temporal response, are present in the non-coding sequence of thejhbpgene. An analysis of exon locations and intron phases indicates thatjhbpgene organization is related to theretinol binding proteingene, a member of the lipocalin family.
Interaction of thiamin diphosphate with phosphorylated and dephosphorylated mammalian pyruvate dehydrogenase complex
Authors: Liu Xiaoqing , Bisswanger Hans
Published: February 2005

Kinetic and binding studies were carried out on substrate and cofactor interaction with the pyruvate dehydrogenase complex from bovine heart. Fluoropyruvate and pyruvamide, previously described as irreversible and allosteric inhibitors, respectively, are strong competitive inhibitors with respect to pyruvate. Binding of thiamin diphosphate was used to study differences between the active dephosphorylated and inactive phosphorylated enzyme states by spectroscopic methods. The change in both the intrinsic tryptophan fluorescence and the fluorescence of the 6-bromoacetyl-2-dimethylaminonaphthalene-labelled enzyme complex produced on addition of the cofactor showed similar binding behaviour for both enzyme forms, with slightly higher affinity for the phosphorylated form. Changes in the CD spectrum, especially the negative Cotton effect at 330 nm as a function of cofactor concentration, both in the absence and presence of pyruvate, also revealed no drastic differences between the two enzyme forms. Thus, inactivation of the enzyme activity of the pyruvate dehydrogenase complex is not caused by impeding the binding of substrate or cofactor.
Characterization of the glyoxalases of the malarial parasite Plasmodium falciparum and comparison with their human counterparts
Authors: Akoachere Monique , Iozef Rimma , Rahlfs Stefan , Deponte Marcel , Mannervik Bengt , Creighton Donald J. , Schirmer Heiner , Becker Katja
Published: February 2005

The glyoxalase system consisting of glyoxalase I (GloI) and glyoxalase II (GloII) constitutes a glutathione-dependent intracellular pathway converting toxic 2-oxoaldehydes, such as methylglyoxal, to the corresponding 2-hydroxyacids. Here we describe a complete glyoxalase system in the malarial parasitePlasmodium falciparum. The biochemical, kinetic and structural properties of cytosolic GloI (cGloI) and two GloIIs (cytosolic GloII named cGloII, and tGloII preceded by a targeting sequence) were directly compared with the respective isofunctional host enzymes. cGloI and cGloII exhibit lowerKmvalues and higher catalytic efficiencies (kcat/Km) than the human counterparts, pointing to the importance of the system in malarial parasites. A Tyr185Phe mutant of cGloII shows a 2.5-fold increase inKm, proving the contribution of Tyr185 to substrate binding. Molecular models suggest very similar active sites/metal binding sites of parasite and host cell enzymes. However, a fourth protein, which has highest similarities to GloI, was found to be unique for malarial parasites; it is likely to act in the apicoplast, and has as yet undefined substrate specificity. Various S-(N-hydroxy-N-arylcarbamoyl)glutathiones tested asP. falciparumGlo inhibitors were active in the lower nanomolar range. The Glo system ofPlasmodiumwill be further evaluated as a target for the development of antimalarial drugs.
Spatial Segregation of Different Modes of Movement Control in the Whisker Representation of Rat Primary Motor Cortex
Authors: Haiss Florent , Schwarz Cornelius
Published: February 2005

What is mapped on the surface of the primary motor cortex (M1)? The classic somatotopic map holds true on the level of limb representations. However, on the small scale (at within-limb representations), neither somatotopy nor movement dynamics/kinematics seem to be organizational principles. We investigated the hypothesis that integrated into the body representation of M1 there may be separate representation of different modes of motor control, using different subcortical computations but sharing the same motor periphery. Using awake rats and long intracortical stimulation trains in M1 whisker representation (wM1) revealed that natural-like, rhythmic whisking (normally used for tactile exploration) can be evoked from a posteromedial subregion of wM1. Nonrhythmic whisker retraction, on the other hand, was evoked in an adjacent but more anterolaterally located region within wM1. Evoked whisker retraction was always accompanied by complex movements of the face, suggesting that the respective subregion is able to interact with other representations in specific behavioral contexts. Such associations were absent for evoked rhythmic whisking. The respective subregion rather seemed to activate a downstream central pattern generator, the oscillation frequency of which was dependent on the average evoked cortical activity. Nevertheless, joint stimulation of the two neighboring subregions demonstrated their potency to interact in a functionally useful way. Therefore, we suggest that the cause of cortical separation is the specific drive of subcortical structures needed to generate different types of movements rather than different behavioral contexts in which the movements are performed.
Piezoresistive Scanning Proximity Probes for Nanoscience (Piezoresistive Raster-Kraftsonden für die Nanowissenschaften)
Authors: Rangelow Iwo W.
Published: February 2005

This article is devoted to the realization of piezoresistive sensors used in scanning probe microscopy. It is expected that in the near future major technological breakthroughs in scanning proximal probe nanotools will allow for key scientific impact on analysis and synthesis of nanostructures. All the piezoresistive cantilever sensors described here are based on advanced silicon micromachining and standard CMOS processing. Moreover, using a newly optimized piezoresistive detection scheme process comprising a Wheatstone bridge, we have designed and fabricated piezoresistive cantilevers for atomic force microscopy, which improve surface topography resolution by an order of magnitude to 0.1 nm. The elegance of this concept is that by using an almost identical detection principle and differently functionalized tips or cantilever surfaces, we can detect subtle sample interactions (mechanical, electrical, thermal, and chemical) with a significantly more compact system than with optical beam deflection techniques. For noncontact scanning force microscopy, we integrate a thermally driven bimorph actuator with the piezoresistive cantilever and make use of direct-oscillation in a higher flexural mode. The cantilever then operates in the phase-shift atomic force microscopy (AFM) detection technique.
Thermomechanische Einflüsse der Chipklebung auf die Genauigkeit mikromechanischer Drucksensoren Teil 2: Experimentelle Verifikation (Thermomechanical Effects of the Adhesive Die Attachment on the Accuracy of MEMS Pressure Sensors)
Authors: Deier Erik , Hoyden Jens , Wilde Jürgen , Becker Klaus
Published: February 2005

Thermomechanische Belastungen können die Funktionalität mikromechanischer Sensoren stark beeinflussen. Im ersten Teil dieser Arbeit wurde das thermomechanische Verhalten geklebter Drucksensoren mit der Finite-Elemente-Methode simuliert. In diesem Teil werden Prüfungen zur Verifikation der Simulationsergebnisse vorgestellt. Dazu werden die Messergebnisse zu den Kennlinien verschieden aufgebauter Drucksensoren unter Betriebsbedingungen vorgestellt. Insbesondere der Einfluss von Druck und Temperatur wird für die untersuchten Sensorkonfigurationen ausgewertet.
Fehlerkorrektur piezoresistiver Drucksensoren mit optimierter Kalibrierung des Signalwandlers (Error Correction of Piezoresistive Pressure Sensors by Optimised Signal Conditioner Calibration)
Authors: Wohlgemuth Christian , Lotz Peter , Werthschützky Roland
Published: February 2005

Für die mikrocontrollerbasierte Fehlerkorrektur von piezoresistiven Drucksensoren ist eine aufwändige messtechnische Erfassung des Sensorkennfeldes notwendig. Mithilfe einer optimierten Messstrategie und unter Verwendung von typischen Werten der Sensorcharge kann die Anzahl der durchzuführenden Messungen deutlich gesenkt werden.
Piezoresistive Chemosensoren auf der Basis von Hydrogelen (Piezoresistive Chemical Sensors Based on Hydrogels)
Authors: Günther Margarita , Sorber Jörg , Gerlach Gerald , Suchaneck Gunnar , Thong Thrinh Quang , Arndt Karl-Friedrich , Richter Andreas
Published: February 2005

Hydrogele zeigen in Abhängigkeit von der sie umgebenden Flüssigkeit ein starkes Quellungsvermögen. Dies kann für die Schaffung chemischer Sensoren, z.B. für die Messung des pH-Wertes, ausgenutzt werden. Dafür lassen sich piezoresistive Sensoren nutzen, wobei das quellende Hydrogel zu einer Verformung der Silizium-Biegeplatte des Sensorchips führt. Es wurden die Ausgangsspannung in Abhängigkeit vom pH-Wert untersucht und die für eine hohe Signalreproduzierbarkeit erforderlichen Messbedingungen ermittelt.