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PubMed2006

Disappearance of the budding yeast Bub2-Bfa1 complex from the mother-bound spindle pole contributes to mitotic exit.

Budding yeast spindle position checkpoint is engaged by misoriented spindles and prevents mitotic exit by inhibiting the G protein Tem1 through the GTPase-activating protein (GAP) Bub2/Bfa1. Bub2 and Bfa1 are found on both duplicated spindle pole bodies until anaphase onset, when they disappear from the mother-bound spindle pole under unperturbed conditions. In contrast, when spindles are misoriented they remain symmetrically localized at both SPBs. Thus, symmetric localization of Bub2/Bfa1 might lead to inhibition of Tem1, which is also present at SPBs. Consistent with this hypothesis, we show that a Bub2 version symmetrically localized on both SPBs throughout the cell cycle prevents mitotic exit in mutant backgrounds that partially impair it. This effect is Bfa1 dependent and can be suppressed by high Tem1 levels. Bub2 removal from the mother-bound SPB requires its GAP activity, which in contrast appears to be dispensable for Tem1 inhibition. Moreover, it correlates with the passage of one spindle pole through the bud neck because it needs septin ring formation and bud neck kinases.

Alleles↗

PubMed2001

Comparison of symptoms related to positioning of double-pigtail stent in upper pole versus renal pelvis.

PURPOSE: This study was a comparison of the symptomatology associated with placement of the upper coil of a double-pigtail stent in the upper pole or the renal pelvis. PATIENTS AND METHODS: A prospective study with 40 patients was performed. In 20 patients, the stent was placed in the upper pole (Group A) and in another 20 patients (Group B) in the renal pelvis. A questionnaire was addressed to all patients before the removal of the stent concerning the presence and severity of flank pain (using a standardized 10-point scale), the presence and severity of urinary urgency (using a standardized 10-point scale), the presence of dysuria, and quality of life with the stent in place. RESULTS: Flank pain was present in 17 (85%) and 15 (75%) patients in Groups A and B, respectively. The average severity of flank pain was 4.3 (range 0-7) and 4.5 (range 0-10) in Group A and B, respectively (p = 0.764). Urinary urgency was present in 13 (65%) and 15 (75%), patients in Group A and B, respectively. The average severity of urgency was 3.1 (range 0-7) and 5.3 (range 0-10) in Group A and B, respectively (p = 0.037). Dysuria was present in 4 (20%) and 13 (65%), and the average quality of life score was 2.5 and 3.05 in Group A and B, respectively (p = 0.04). CONCLUSION: Positioning of the proximal end of the double-pigtail stent in the upper pole of the kidney appears to be better tolerated by patients than is the standard insertion in the renal pelvis.

Adult↗

PubMed2003

Measurement of renal anatomy for prediction of lower-pole caliceal stone clearance: reproducibility of different parameters.

BACKGROUND AND PURPOSE: The architecture of the lower renal pole seems to have a considerable influence on caliceal stone clearance after different therapeutic modalities. The published data are partially inconsistent, and publications on reproducibility are completely lacking. The aim of this study was to evaluate the intraobserver and interobserver reproducibility of different measures of lower-calix anatomy. MATERIALS AND METHODS: We studied the intraobserver and interobserver reproducibility of parameters describing the lower-pole anatomy that are significant for treatment outcome. Forty renal units without urologic disease were analyzed by five independent urologists. Infundibular length (IL), infundibular width (IW), and lower infundibulopelvic angles (LIP) were measured by the Elbahnasy (LIP I), Keeley (LIP II), and Gupta (LIP III and LIP IV) methods. Statistical analysis of each parameter and investigator was performed. RESULTS: All LIP angles showed low interobserver correspondence: correlation coefficients (CC) did not exceed 0.44 (P < 0.05). Even the relatively clearly defined parameters IW and IL achieved CCs of only 0.63 and 0.49, respectively. The intraobserver correlation achieved better results: 0.73 (LIP I), 0.84 (LIP II), 0.73 (LIP III), 0.65 (LIP IV), 0.88 (IL), and 0.82 (IW). With the Elbahnasy method, almost all renal units were classified as favorable for stone persistence after shockwave lithotripsy. With the Keeley and Gupta methods, more than 50% of the kidneys were defined as having low clearance probability. CONCLUSIONS: Assessment of the chosen parameters is difficult and shows high interobserver variation. Inexperience in measuring the specific angles and low imaging quality can limit correct evaluation. The large number of kidneys with anatomy inappropriate for clearance of lower-pole stones may explain the poor outcome of shockwave treatment for stones in a lower calix. Prospective studies will determine the clinical value of anatomic assessments.

Humans↗

PubMed1997

Effectiveness of SWL for lower-pole caliceal nephrolithiasis: evaluation of 452 cases.

The authors report on the treatment of lower-pole caliceal nephrolithiasis with extracorporeal shockwave lithotripsy (SWL) using the Czech-made Medilit M-5 lithotripter. In 310 patients, they have performed 452 treatments and evaluated the results 3 months after the last session using plain radiographs and ultrasound examination. The effectiveness of treatment and the success rate of SWL decreased with increasing size of stones: with stones >20 mm, it declined to 30%. This poor success rate was attributable not only to the size of the concrement, but also to its location in a lower calix, which is unfavorable for the passage of fragments. For big lower-pole caliceal stones (>20 mm in the longest diameter), the authors recommend percutaneous nephrolithotomy as the primary management method, the effectiveness of which does not depend on the size of the stone. The success rate achieved in treating the lower-pole caliceal lithiasis using the Medilit M-5 machine was 61.3%, similar to that achieved with other lithotripters.

Adult↗

PubMed1998

Lower-pole caliceal stone clearance after shockwave lithotripsy, percutaneous nephrolithotomy, and flexible ureteroscopy: impact of radiographic spatial anatomy.

Spatial anatomy of the lower renal pole, as defined by the infundibulopelvic angle (LIP angle), infundibular length (IL), and infundibular width (IW), plays a significant role in the stone-free rate after shockwave lithotripsy. A wide LIP angle, a short IL, and a broad IW, individually or in combination, favor stone clearance, whereas a LIP <70 degrees, an IL >3 cm, or an IW < or =5 mm are individually unfavorable. When all three unfavorable factors or an unfavorable LIP and IL coexist, the post-SWL stone-free rate falls to 50% or less. Using these criteria, more than one fourth of our patients with a lower-pole calculus might have been better served by an initial percutaneous or perhaps ureteroscopic procedure, neither of which is significantly affected by the lower-pole spatial anatomy.

Adolescent↗

PubMed2000

Is there a simpler method for predicting lower pole stone clearance after shockwave lithotripsy than measuring infundibulopelvic angle?

BACKGROUND AND PURPOSE: Several anatomic factors influence the clearance of lower pole stones treated with shockwave lithotripsy (SWL). One of these is the infundibulopelvic angle, but its measurement is complex. METHODS: We proposed a more simple measure of caliceal dependence, the caliceal pelvic height (CPH), which we defined as the distance between a horizontal line from the lowermost point of the calix containing the stone to the highest point of the lower lip of the renal pelvis. RESULTS: In 62 patients who had SWL for solitary lower pole stones, a CPH < 15 mm was associated with a stone clearance rate of 92%, whereas with a CPH > or = 15 mm, the clearance rate was only 52% (p < 0.05). A majority (74%) of the patients with an infundibular width of > or = 5 mm were rendered stone free compared with 40% of those with a width of < 5 mm (p < 0.05). CONCLUSION: Measurement of the CPH, in conjunction with other anatomic factors, may more accurately predict the outcome of SWL in patients with lower pole stones.

Adult↗

PubMed1993

An attempt to hybridize Drosophila species using pole cell transplantation.

We have made hybrid embryos in Drosophila by pole cell transplants, by transferring pole cells from two species, D. rajasekari and D. eugracilis, into sterile D. melanogaster hosts. These females were then mated to melanogaster males and the older these females were, the further their hybrid offspring developed. In the case of the rajasekari/melanogaster hybrids, the embryos form cuticle but had defective heads, while the eugracilis/melanogaster hatched as larvae that grew but did not moult to the second instar. Hybrid pole cells could be transferred to melanogaster hosts but they failed to make eggs.

Animals↗

PubMed1980

Serologic evidence for parainfluenzavirus infection during isolation at South Pole Station, Antarctica.

Two distinct mid-winter outbreaks of respiratory tract illness (RTI) occurred among South Pole Station personnel during the winterover period of 1976. One outbreak began early in May eight weeks after total isolation began, the second occurred in August and September after 20 weeks of complete social isolation. Sequential sera collected from 16 of the 18 subjects wintering at South Pole during 1976 were tested by hemagglutination inhibition for antibody against parainfluenzavirus types 1 and 3. Serologic responses were detected against parainfluenzavirus 1 and 3 antigens during the outbreak that occurred in May, and one subject showed a response to parainfluenzavirus 1 in September. Serologic responses occurred in both symptomatic and asymptomatic subjects and were chronologically compatible with the observed illnesses. Throat swabs collected both routinely during the winter and during each outbreak of illness and maintained at -70 C failed to reveal the causative agent when inoculated into cell culture at the home laboratory the following year. Outbreaks of mid-winter RTI and serologic responses in adult subjects isolated at South Pole Station suggest persistence of parainfluenzavirus in the human adult. Confirmation of this observation will require recovery of the virus during outbreaks of RTI within this isolated community.

Adult↗

PubMed2004

Stomata open at night in pole-sized and mature ponderosa pine: implications for O3 exposure metrics.

Ponderosa pine (Pinus ponderosa Dougl. ex Laws.) is widely distributed in the western USA. We report the lack of stomatal closure at night in early summer for ponderosa pine at two of three sites investigated. Trees at a third site with lower nitrogen dioxide and nitric acid exposure, but greater drought stress, had slightly open stomata at night in early summer but closed stomata at night for the rest of the summer. The three sites had similar background ozone exposure during the summer of measurement (2001). Nighttime stomatal conductance (gs) ranged from one tenth to one fifth that of maximum daytime values. In general, pole-sized trees (< 40 years old) had greater nighttime gs than mature trees (> 250 years old). In late summer, nighttime gs was low (< 3.0 mmol H2O m(-2) s(-1)) for both tree size classes at all sites. Measurable nighttime gs has also been reported in other conifers, but the values we observed were higher. In June, nighttime ozone (O3) uptake accounted for 9, 5 and 3% of the total daily O3 uptake of pole-sized trees from west to east across the San Bernardino Mountains. In late summer, O3 uptake at night was < 2% of diel uptake at all sites. Nocturnal O3 uptake may contribute to greater oxidant injury development, especially in pole-sized trees in early summer.

Ozone↗

PubMed2002

Vascularized bone grafting and herbert screw fixation of scaphoid nonunions with avascular proximal poles.

Nonunion of the fractured scaphoid can present a difficult surgical problem, especially in fractures near the proximal pole. The incidence of nonunion is greater in this region, in which the vascularity of the proximal fracture segment is compromised and the proximal fragment is small and resists rigid fixation. Recent development of better vascularized bone grafting techniques has provided a tool with which to address this vexing problem. Because many authors had previously shown the advantage of rigid fixation in obtaining scaphoid union, it seemed advantageous to us to combine these two methods-rigid fixation and improved vascularity. In this article, we present in detail our technique for treating patients with very small proximal pole fractures in which the proximal fragment makes up less than 20% of the scaphoid. For practical purposes, all of these fractures have a proximal fragment that is avascular. We use a vascularized bone graft as described by Zaidemberg et al. in combination with more rigid fixation of proximal pole fractures using the Herbert mini screw. Although the technique presented requires the surgeon to use precise surgical technique, early results have been encouraging, and patients with very small fracture fragments can be treated successfully.

Journal Article↗

PubMed2004

The impact of caliceal pelvic anatomy on stone clearance after shock wave lithotripsy for pediatric lower pole stones.

PURPOSE: The clearance rather than stone disintegration of lower pole stones after shock wave lithotripsy (SWL) is significantly inferior according to the other localizations of the kidney. We retrospectively evaluated the impact of caliceal pelvic anatomy on stone clearance after SWL for pediatric lower pole stones. MATERIALS AND METHODS: We treated 163 renal units (RUs) in children 16 years old or younger with SWL between March 1992 and February 2002. In 36 RUs stones were localized in the lower calices. All patients were treated with sedoanalgesia except 3 (8%) who were treated under general anesthesia. Patients were evaluated by excretory urography and ultrasonography 12 weeks after the last session, and were designated as stone-free or with residual stone. The lower infundibular length, width, length-to-width ratio, pelvic caliceal height and lower infundibulopelvic angle were determined on standard excretory urography before SWL. All measurements were done by 1 urologist who was unaware of the results. Statistical analysis was performed with chi-square, Fisher's exact and Mann-Whitney U tests. ROC analysis was done to determine the cutoff points of caliceal anatomy measurements for stone clearance. RESULTS: We treated 36 RUs in 23 males and 10 females with isolated lower caliceal stones. Median patient age was 10.5 years (range 2 to 16). Median stone burden was 0.7 cm (range 0.2 to 4), and median number of shock waves and energy used for the entire patient population was 1,500 and 17.2 kV, respectively. Overall stone-free rates for the 36 RUs were 61% after a median treatment session of 1 (range 1 to 7) and retreatment rates were 39%. Of the patients rendered free of stones 13 (59%) were treated in a single SWL session and 9 (41%) underwent 2 or more sessions. Median lower infundibular length, width, length-to-width ratio and pelvic caliceal height in the stone-free and residual stone group were 25.5, 28.0 mm, 4.5, 5.0 mm, 6.4, 5.5 mm and 21.5, 21.5 mm, respectively (p = 0.810, 0.327, 0.511 and 0.511). Median lower infundibulopelvic angle in the stone-free and residual stone groups was 92.50 and 92.50 degrees, and 60.0 and 54.50 degrees, respectively (p = 0.860 and 0.089). On ROC analysis no parameter predicting stone-free rate and cutoff points of caliceal anatomy measurements for stone clearance was found. CONCLUSIONS: Our results suggest that caliceal pelvic anatomy in pediatric lower pole stones has no significant impact on stone clearance after SWL. There was a highly significant relation between retreatment rates and stone burden, which should be considered for determining the treatment modality.

Adolescent↗

PubMed1986

Biophysics of pole formation of gram-positive rods.

During pole formation in Bacillus subtilis the inner and outer surfaces of the nascent pole are enlarged by almost exactly the same extent. This means that the stress is almost uniformly distributed throughout the polar wall. This differs from the situation in the cylindrical side wall, where most of the stress is exerted in the outer portions of the intact wall. Because the stress is shared more uniformly, the maximum strain in any part of the polar wall is reduced, compared with the maximum strain within the side wall. The lowered stress may account, in part, for the resistance of the polar wall to hydrolysis by autolytic enzymes under certain conditions. The shape of the newly completed pole is significantly different from the spherical shape that the hydrostatic pressure would tend to produce. It does, however, achieve the shape that maximizes the polar volume under the restrictions arising due to expansion along the circumference not being possible near the junction of cylindrical and polar wall.

Bacillus subtilis↗

PubMed1992

Analysis of ECG from pole-zero models.

A complete solution to the fundamental problem of ECG analysis, viz., delineation of the signal into its component waves, is proposed from a system theoretic point of view. The discrete cosine transform of a bell shaped biphasic function is approximated mathematically by a system function with two poles and two zeros, i.e., of order (2, 2). Using this concept as the basis, a pole-zero model of suitable order is derived from the discrete cosine transform (DCT) of the given signal using Steiglitz-McBride method. This model is expanded into a unique set of partial fractions each of order (2, 2), and a biphasic function is recovered from each one of these fractions in the inverse process. Each of the P and T waves usually requires only one biphasic function, while the QRS complex needs two or at most three such fractions. A one-to-one relationship between the pole pattern in the z-plane and component wave pattern in the time signal is established. Results of analysis of continuous strips of ECG show that the delineated component waves are in excellent agreement with the original waves both qualitatively and quantitatively. The method is robust for the analysis of signals with artifacts of various kinds, independent of the sampling rate used, and is free from ad hoc back and forth search procedures.

Algorithms↗

PubMed2004

The Sec14 family glycerophospholipid-transfer protein is required for structural integrity of the spindle pole body during meiosis in fission yeast.

The fission yeast spo20+ gene encodes a glycerophospholipid-transfer protein. spo20 mutants are unable to assemble the forespore membrane properly. Here we studied the structural integrity of the spindle pole body (SPB) in spo20-H6 mutants during meiosis. Meiotic cells expressing a GFP-tagged SPB marker protein, Spo15-GFP, showed an excess number of SPBs, some of which were not localized to the spindle poles and were termed 'pseudo-SPBs'. Formation of spindles for meiosis I was significantly delayed in spo20-H6 cells, although the morphology of spindles and segregation of the sister chromatids seemed normal. The SPB of spo20-H6 contained meiosis-specific outer plaques, though outermost layers were less evident. Time-lapse studies of spo20-H6 cells showed that the pseudo-SPBs originated from normal SPBs at the spindle poles during meiosis I. Among the SPB components tested, Spo15, Spo13, Sad1 and Cut12 were localized to the pseudo-SPBs, but Sid4 was not always present. Alp4, a component of the gamma-tubulin complex, was also present in about 40% of the pseudo-SPBs. The forespore membranes initiated from both the SPBs and the pseudo-SPBs. We conclude that Spo20 plays a role in maintaining the structural integrity of the meiotic SPB, besides supplying membrane vesicles for forespore membrane assembly.

Alleles↗

PubMed1990

Phrenic nerve stimulation for central ventilatory failure with bipolar and four-pole electrode systems.

A multi-channel phrenic nerve stimulator developed in Tampere has been implanted into seven patients with C2-tetraplegia and into three patients with central sleep apneas. Six bipolar cuff electrodes were implanted bilaterally into the neck. Two four-pole cuff and 14 four-pole noncuff electrodes were used in seven patients and to replace one bipolar electrode. Four-pole electrodes were implanted within the thorax. Seven patients achieved total independence from conventional ventilators within 4 months of implantation, and one for 18 hours each day. Two patients died 12 days and 3 months after implantation and two patients after having achieved independence from mechanical ventilators from causes unrelated to the stimulators. Reoperations were necessary because of dislocation of receivers, electrodes, electrode lesions, nerve injuries, and technical failures in seven patients. Most of the problems appeared in two patients with obesity and in three patients with very thin phrenic nerves. Single unit prototypes failed technically more frequently than units of prototype serial fabrication. New electrode design, progress in the manufacture of receivers, and improved implantation technique should help to diminish failures in future.

Adolescent↗

PubMed1979

Intersubject agreement concerning relationships between the positive and negative poles of constructs in repertory grid tests.

Previous research indicate that there is more intersubject agreement concerning patterns of correlations between constructs than concerning how specific elements are rated on each construct. In this study, Canadian undergraduates (15 women, 15 men) rank-ordered eight photographs of strangers separately on the basis of the positive and negative poles of six constructs. The results indicated that there is more consensus concerning specific patterns of relationships between the positive poles of constructs than concerning those between their negative poles. Some implications of this finding for repertory grid assessment and research were discussed.

Affect↗

PubMed1997

Occipital pole area and language dominance.

A previous report demonstrated a relationship between asymmetries of occipital lobe length measured on magnetic resonance images (MRIs) and the hemisphere verified as dominant for language. This study sought to discern whether asymmetry in occipital pole area is more predictive of the hemisphere dominant for language. Language dominance was identified by the Wada test in 55 patients evaluated for surgical treatment of epilepsy. In a blinded fashion, an examiner measured bilateral occipital pole area on MRIs for each patient. Asymmetry of the occipital pole area on the MRI made at 10 mm above the tentorium was significantly related to language dominance. This two-dimensional analysis was better than previously described linear measurements in discriminating patients with left-hemisphere dominance for language.

Adult↗

PubMed1985

A single-pole model for the propagation of ultrasound in soft tissue.

A minimum-phase function, which characterizes the velocity dispersion in tissue was calculated from measured attenuation. This function was incorporated into a causal tissue model. Predictions of attenuation using the minimum-phase function with just a single pole matched measured attenuation in the 1- to 10-MHz range within a few percent. Dispersion of phase velocity predicted by the single-pole model was comparable to measured dispersion. The frequency associated with the single pole, which is a relaxation frequency, decreased with hemoglobin concentration and collagen content but increased with temperature. The electrical equivalent circuit for this model is a delay coupled with a low-pass filter which can be configured as a resistance in series with a parallel combination of resistance and capacitance.

Collagen↗