Grambank reveals the importance of genealogical constraints on linguistic diversity and highlights the impact of language loss

While global patterns of human genetic diversity are increasingly well characterized, the diversity of human languages remains less systematically described. Here, we outline the Grambank database. With over 400,000 data points and 2400 languages, Grambank is the largest comparative grammatical database available. The comprehensiveness of Grambank allows us to quantify the relative effects of genealogical inheritance and geographic proximity on the structural diversity of the world's languages, evaluate constraints on linguistic diversity, and identify the world's most unusual languages. An analysis of the consequences of language loss reveals that the reduction in diversity will be strikingly uneven across the major linguistic regions of the world. Without sustained efforts to document and revitalize endangered languages, our linguistic window into human history, cognition, and culture will be seriously fragmented.

[Clinical relevance of multislice CT of the spine after osteosynthesis]

PURPOSE

To examine the clinical relevance of multislice CT (MSCT) scans in postoperative checks of the spine after osteosynthesis.

MATERIAL AND METHODS

The results of x-rays (apical lateral) in 30 patients having spinal surgery involving osteosynthesis (5 x metastasis, 20 x fractures, 3 x spondylolisthesis, 2 x scoliosis) were correlated to those of MSCT (140 kV, 200 mAs, collimation 4 x 1 mm, pitch 0.75; VolumeZoom, Siemens, Erlangen, Germany) with multiplanar reconstruction. Two radiologists independently checked the conventional x-ray and multislice CT scans for anatomical positioning, damage of osteosynthetic material, and intraspinal dislocation of bone fragments.

RESULTS

By correlating conventional spinal x-rays with MSCT, additional diagnostic information was gained. In 9 of 30 patients MSCT revealed the extraosseal location of a screw tip (x-ray, 5/30), in 8/30 patients a narrowing of the spinal canal by osteosynthetic material was detected in MSCT (x-ray, 4/30), in 2/30 patients osteal fragments were detected in the vertebral canal by MSCT (x-ray, 0/30). In MSCT and in conventional x-ray a fracture of the osteosynthesis was correctly diagnosed in 3 patients. One patient underwent corrective surgery for dislocated osteosynthetic material, which was solely diagnosed with MSCT.

CONCLUSION

Due to the high degree of additional diagnostic information MSCT seems to be the method of choice for postoperative spinal surgery involving osteosynthesis.

[Dose optimization for multislice computed tomography protocols of the midface]

PURPOSE

To optimize multislice computed tomography (MSCT) protocols of the midface for dose reduction and adequate image quality.

MATERIALS AND METHODS

MSCT (Somatom Volume Zoom, Siemens) of the midface was performed on 3 cadavers within 24 hours of death with successive reduction of the tube current, applying 150, 100, 70 and 30 mAs at 120 kV as well as 40 and 21 mAs at 80 kV. At 120 kV, a pitch of 0.875 and collimation of 4x1 mm were used, and at 80 kV, a pitch of 0.7 and collimation of 2x0.5 mm. Images were reconstructed in transverse and coronal orientation. Qualitative image analysis was separately performed by two radiologists using a five-point scale (1 = excellent; 5 = poor) applying the following parameters: image quality, demarcation and sharpness of lamellar bone, overall image quality, and image noise (1 = minor; 5 = strong). The effective body dose [mSv] and organ dose [mSv] of the ocular lens (using the dosimetry system "WINdose") were calculated, and the interobserver agreement (kappa coefficient) was determined.

RESULTS

For the evaluation of the lamellar bone, adequate sharpness, demarcation and image quality was demonstrated at 120 kV/30 mAs, and for the overall image quality and noise, 120 kV/40 mAs was acceptable. With regard to image quality, the effective body dose could be reduced from 1.89 mSv to 0.34 mSv and the organ dose of the ocular lens from 27.2 mSv to 4.8 mSv. Interobserver agreement was moderate (kappa = 0.39).

CONCLUSION

Adequate image quality was achieved for MSCT protocols of the midface with 30 mAs at 120 kV, resulting in a dose reduction of 70 % in comparison to standard protocols.

[Image quality of thin- and thick-slice MSCT reconstructions in low-contrast objects (liver lesions) with equal doses]

PURPOSE

To evaluate the image quality of thin-section MSCT examinations of low-contrast objects such as liver lesions, and to find out whether a thin slice technique requires an increase in radiation dose.

MATERIALS AND METHODS

MSCT examinations of the liver were performed in the portal venous phase on a Volume Zoom Scanner (Siemens, Erlangen) with a collimation of 4 x 2.5 mm, 120 kV, 125 mAs and table speed of 12.5 mm. Forty small hypodense liver lesions with a mean size of 3 mm (1 to 8 mm) were reconstructed using a slice thickness of 3, 5, 7, and 10 mm. All lesions were evaluated for each slice thickness by 3 independent radiologists using a 5-point scale (excellent to poor) for the following 7 criteria: contrast, demarcation and contour of the lesion, image noise and quality, demarcation of liver veins and liver contour. The mean values of the reviewers' scores were calculated. The correlation of the three observers in the evaluation of the criteria was determined using the Kendall's Tau coefficient.

RESULTS

The 3-mm thin sections were excellent in the evaluation of lesion detection, lesion contrast and lesion contour with a mean score of 1.4 compared to 4.1 for 10-mm sections. Concerning the criteria image quality and liver contour, thin sections achieved the best results in our series. Image noise was pronounced in thin sections but did not affect negatively the image analysis. Interrater agreement was 0.53 for the criterium image noise.

CONCLUSION

Thin sections in MSCT examinations of low contrast objects such as liver lesions do not require an increase in radiation dose because the increase in image noise is compensated by improved lesion contrast.

[Diagnostic imaging in polytrauma: comparison of radiation exposure from whole-body MSCT and conventional radiography with organ-specific CT]

PURPOSE

To compare the radiation dose of whole-body multislice CT (MSCT) and conventional radiography with organ-specific CT in polytrauma.

MATERIALS AND METHODS

The whole-body MSCT encompassing brain, neck and midface, chest, abdomen and pelvis was performed on a Somatom Volume Zoom (Siemens). Conventional radiography consisted of chest and cervical, thoracic and lumbar spine in two views as well as pelvis (Polymat, Siemens). Three combinations of organ specific CT were chosen: CT examination of (1) head and cervical spine, (2) head, cervical spine and chest, (3) head, cervical spine and abdomen. The effective doses of whole-body MSCT and conventional radiography with organ-specific CT were calculated.

RESULTS

Effective doses were 20 mSv for whole-body MSCT, 2 mSv for conventional x-ray, and 5 mSv for combination (1), 8 mSv for combination (2) and (3) 16 mSv for combination (3) of the organ-specific CT. The ratio of radiation dose between whole-body MSCT and radiography was 10 : 1. This ratio was reduced to 3 : 1, 2 : 1 and 1 : 1 when a combination of radiography and CT was performed.

CONCLUSIONS

Whole-body MSCT in polytrauma compared to conventional radiography with organ-specific CT induces a threefold increased dose in unfavorable situations and no increased dose in favorable situations. Nevertheless, routine use of whole-body MSCT should be critically evaluated and should be adapted to the clinical benefit.

[Multislice CT of the pelvis: dose reduction with regard to image quality]

PURPOSE

To optimize the examination protocols of multislice CT (MSCT) of the pelvis for dose reduction with regard to image quality.

MATERIALS AND METHODS

MSCT of the pelvis was performed on 5 cadaver specimens with stepwise reduction of the tube current at 140 kV (250, 200, 150, 100, 75, 50, 35, 25 mAs) and 120 kV (50, 27 mAs). The remaining scan parameters like collimation (4 x 1 mm) and table speed of 4 mm per rotation remained unchanged. Axial sections and coronal reconstructions were used to evaluate cortex, trabecular structures, subjective image quality, image noise and detail detectability (pelvis and SI joint), with evaluation performed independently by four blinded experienced radiologists on a 5-point scale. Kappa coefficient, accuracy of the observers to sort the films with regard to dose reduction and mean scores of image evaluation were determined for statistical analysis.

RESULTS

The deterioration of the image quality was most pronounced for all criteria between 75 mAs and 50 mAs at 140 kV. Good results with adequate image quality were obtained for detail detectability at 50 mAs and 140 kV (effective dose [E]: 3.3 mSv) and for the remaining four criteria at 75 mAs (E: 4.9 mSv). There was a moderate agreement between the four observers (kappa coefficient: 0.27). All observers were excellent in arranging the images according to the increasing dose reduction.

CONCLUSIONS

Image quality of MSCT of the pelvis appears to be acceptable at 75 mAs and 140 kV with the dose reduced to 46% of the average value of the nation-wide survey of the German Roentgen Society in 1999 for this type of examination.

[Quality rating of MR-cholangiopancreatography with oral application of iron oxide particles]

PURPOSE

To compare image quality in magnetic resonance cholangiopancreatography (MRCP) performed with and without oral application of Lösferron (ferrous gluconate, Lilly Pharma, Hamburg).

MATERIALS AND METHODS

A prospective study compares MRCPs performed on 52 patients with a 1.5 T clinical whole body scanner using a standard body coil. After randomization, patients ingested either 0.5 l of Lösferron (n = 27, group 1) or no oral contrast agent (n = 25, group 2) prior to the examination. 7 RARE (40 to 20 degrees) sequences were obtained, followed by selected 3 mm HASTE (T 2 -weighted with fat suppression) sequences. After blinding, image quality was rated by two radiologists using a scale of 1 (not discernible) to 5 (very well discernible). The following sections of the biliary ductal system were evaluated: left and right hepatic duct, extrahepatic bile duct and intrapancreatic bile duct. The pancreatic duct was evaluated by its location: head, body and tail of the pancreas. A Wilcoxon-Mann-Whitney test was used to determine significant differences (p < 0.05) between sampled ductal segments. Correction for multiple testing was applied.

RESULTS

The oral application of Lösferron was well tolerated by all patients, and all sequences could be acquired and evaluated in all 52 patients. For the different sections of the biliary system, the mean ratings with and without Lösferron were, respectively, 3.28 and 3.36 for the left hepatic duct, 3.26 and 3.33 for the right hepatic duct, 3.46 and 4.0 for the extrahepatic bile duct, and 2.8 and 3.48 for the intrapancreatic bile duct. The corresponding ratings for the pancreatic duct were 2.8 and 3.24 for the pancreatic head, 2.84 and 3.38 for the pancreatic body, and 2.68 and 3.22 for the pancreatic tail. The differences with and without contrast agent were not statistically significant. Interobserver variability was between 0.37 for the pancreatic duct in the tail of the pancreas and 0.66 for the right hepatic duct.

CONCLUSION

Despite the trend toward a better rating of the image quality for all sections of the pancreaticobiliary ductal system with Lösferron, a significant difference was not found in any ductal section after correction for multiple testing. Thus, we believe that the ingestion of Lösferron is not absolutely required prior MRCP.

Pressure evolution of the high-frequency sound velocity in liquid water

The high-frequency sound velocity v( infinity ) of liquid water has been determined to densities of 1.37 g/cm(3) by inelastic x-ray scattering. In comparison to the hydrodynamic sound velocity v(0), the increase of v( infinity ) with density is substantially less pronounced, indicating that, at high density, the hydrogen-bond network is decreasingly relevant to the physical properties of liquid water. Furthermore, we observe an anomaly in v( infinity ) at densities around 1.12 g/cm(3), contrasting the smooth density evolution of v(0).

MR elastography of the breast:preliminary clinical results

PURPOSE

Imaging of breast tumors and various breast tissues using magnetic resonance (MR) elastography (MRE) to explore the potential of elasticity as a new parameter for the diagnosis of breast lesions.

METHODS

Low-frequency mechanical waves are transmitted into breast tissue by means of an oscillator. The local characteristics of the mechanical wave are determined by the underlying elastic properties of the tissue. Theses waves can be displayed by means of a motion-sensitive spin-echo MR sequence within the phase of the MR image. Elasticity reconstruction is performed on the basis of 8 "snapshots" of each wave within the three spatial directions. We performed in-vivo measurements in 15 female patients with malignant tumors of the breast, 5 patients with benign breast tumors, and 15 healthy volunteers.

RESULTS

Malignant invasive breast tumors documented the highest values of elasticity with a median of 15.9 kPa and a wide range of stiffnesses between 8 and 28 kPa. In contrast, benign breast lesions represented low values of elasticity, which were significantly different from malignant breast tumors (median elasticity: 7.0 kPa; p = 0.0012). This was comparable to the stiffest tissue areas in healthy volunteers (median elasticity 7.0 kPa), whereas breast parenchyma (median: 2.5 kPa) and fatty breast tissue (median: 1.7 kPa) showed the lowest values of elasticity. Two invasive ductal carcinomas had elasticity values of 8 kPa and two stiff parenchyma areas in healthy volunteers had elasticities of 13 and 15 kPa. These lesions could not be differentiated by their elasticity.

CONCLUSION

We conclude that MRE is a promising new imaging modality with the capability to assess the viscoelastic properties of breast tumors and the surrounding tissues. However, from our preliminary results in a small number of patients it is obvious that there is an overlap in the elasticity ranges of soft malignant tumors and stiff benign lesions.

Computer navigation of parapedicular screw fixation in the thoracic spine: a cadaver study

STUDY DESIGN

An in vitro study to investigate the advantages of computer assistance for the purpose of parapedicular screw fixation in the upper and middle thoracic spine.

OBJECTIVES

To evaluate the feasibility and application accuracy of parapedicuar screw insertion with the assistance of an optoelectronic navigation system.

SUMMARY OF BACKGROUND DATA

Because of anatomic limitations, thoracic pedicle screw insertion in the upper and middle thoracic spine remains a matter of controversy. The technique of parapedicular screw insertion has been described as an alternative, although the exact screw position is difficult to control. With the assistance of computer navigation for the screw placement, it might become possible to overcome these challenges.

METHODS

Four human specimens were harvested for this study; 6-mm screws were inserted from T2 to T8 with the assistance of a CT-based optoelectronic navigation system. During surgery virtual images of the screw position were documented and compared with postoperative contact radiographs to determine the application accuracy. The following measurements were obtained: axial and sagittal screw angles as well as the screw distances to the anterior vertebral cortex and the medial pedicle wall.

RESULTS

All 54 screws were inserted in a parapedicular technique without violation of the medial pedicle wall or the anterior or lateral vertebral cortex. The mean +/- standard deviation difference between the virtual images and the radiographs was 1.0 +/- 0.94 mm for the distance to the medial pedicle wall and 1.9 +/- 1.44 mm for the distance to the anterior cortex. The angular measurements showed a difference of 1.6 +/- 1.1 degrees for the transverse screw angle and 2.1 +/- 1.6 degrees for the sagittal screw orientation.

CONCLUSION

With the assistance of computer navigation it is possible to achieve a safe and reliable parapedicular screw insertion in the upper and middle thoracic spine in vitro. The application accuracy varies for the linear and angular measurements and is higher in the axial than in the sagittal plane. It is important for the surgeon to understand these limitations when using computer navigation in spinal surgery.

In vitro function of islets of Langerhans encapsulated with a membrane of porcine chondrocytes for immunoisolation

BACKGROUND/AIMS

Widespread clinical application of islet transplantation remains restricted, because of insufficient methods to prevent rejection and autoimmune destruction of islet grafts. In this study we demonstrate long-term function of islets of Langerhans within a capsule of porcine chondrocytes which may serve as an immunoisolation barrier utilizing the immunoprivileged properties of the chondrocyte matrix.

METHODS

Islets of Langerhans were isolated from Lewis rats, seeded on biodegradable polyglycolic acid polymer, and encapsulated with a monolayer of porcine chondrocytes. The encapsulated constructs and controls were kept in culture for 5 weeks. One group was exposed to a glucose challenge every 5th day. The insulin concentration of the culture medium was measured. Histological and insulin-immunohistochemical studies were performed.

RESULTS

Hematoxylin and eosin histology demonstrated viability of the islets of Langerhans. The intact morphology was demonstrated by Heidenhain staining. Toluidine blue showed viability of surrounding chondrocyte layers. Immunohistochemistry was positive for insulin within the beta cells of the islets. Both encapsulated constructs and nonencapsulated controls showed increasing insulin levels after glucose challenge.

CONCLUSIONS

We can tissue engineer a chondrocyte encapsulation membrane which permits diffusion of glucose and insulin. Islets of Langerhans survive within the chondrocyte capsule, and the glucose/insulin feedback mechanism remains intact.

[Imaging of breast tumors using MR elastography]

PURPOSE

Imaging of breast tumors using MR-Elastography.

MATERIAL AND METHOD

Low-frequency mechanical waves are transmitted into breast-tissue by means of an oscillator. The local characteristics of the mechanical wave are determined by the elastic properties of the tissue. By means of a motion-sensitive spin-echo-sequence these waves can be displayed within the phase of the MR image. Subsequently, these images can be used to reconstruct the local distribution of elasticity. In-vivo measurements were performed in 3 female patients with malignant tumors of the breast.

RESULTS

All patients tolerated the measurement set-up without any untoward sensation in the contact area of skin and oszillator. The waves completely penetrated the breast, encompassing the axilla and regions close to the chest wall. All tumors were localized by MRE as structures of markedly stiffer tissue when compared to the surrounding tissue. Furthermore, in one patient, a metastasis in an axillary lymph node was detected. In all patients, local regions of increased elasticity were found in the remaining parenchyma of the breast, which, however, did not reach the high levels of elasticity found in the tumors.

CONCLUSION

MRE is an imaging modality enabling adjunct tissue differentiation of mammary tumors.

High-resolution tensor MR elastography for breast tumour detection

MR elastography is a novel imaging technique for the visualization of elastic properties of tissue. It is expected that this method will have diagnostic value for the clarification of suspicious breast lesions. Low-frequency mechanical waves are coupled into the tissue and visualized via an MR sequence which is phase-locked to the mechanical excitation. Commonly, elasticity is assumed to be isotropic and reconstruction is performed in only two dimensions. The technique is extended to three dimensions such that the entire symmetric elasticity tensor is assessed. This is achieved by measuring different phases of the mechanical wave during one oscillatory cycle. Thereby it is possible to provide information about the anisotropy of the elasticity tensor. Finite-element simulations as well as phantom experiments are performed to demonstrate the feasibility of the method. Initial clinical results of a breast carcinoma are presented. The analysis of the eigenvalues of the elasticity tensor support the hypothesis that breast carcinoma might exhibit an anisotropic elasticity distribution. The surrounding benign tissue appears isotropic. Thereby new and additional diagnostic information is provided which might help in distinguishing between benign and malignant breast diseases.

[Value of MRI, CT and findings in staging of gynecologic malignancies]

PURPOSE

The present study was designed to compare the value of MRI, CT and clinical examination in local tumor staging of gynaecologic malignancies.

PATIENTS AND METHODS

99 patients with clinically suspected carcinoma of the cervix uteri, ovarian carcinoma or tumor recurrence after gynaecologic cancer underwent all three staging modalities. Furthermore CT and MRI were compared in detecting lymph node metastasis and peritoneal implants.

RESULTS

MRI was superior to CT and clinical staging in local tumor staging with an accuracy of 77% for cervical carcinoma and of 88% for recurrent tumors, whereas CT achieved an accuracy of 65% and 55% and clinical staging 60% and 63% accuracy for carcinoma of the cervix and recurrent cancer. Especially for local staging of these two tumor entities MRI is very useful. MRI and CT reached comparable results in the detection of ovarian tumors with an accuracy of 73% for MRI and 69% for CI. Both imaging modalities also showed equal results in the detection of lymph node metastasis, so that primary the cost saving use of CT tumor staging for ovarian lesions and lymph node metastasis should be favoured.

Microfocusing of hard X-rays with cylindrically bent crystal monochromators

High-energy X-ray focusing with bent-crystal monochromators is known to be hampered by so-called depth or crystal-thickness aberrations. A theoretical model of focus broadening based on the geometrical theory of X-ray diffraction in slightly deformed crystals is presented and compared with experimental data. First, it is shown that depth broadening can be avoided in the Laue geometry by an appropriate choice of asymmetry angle. Based on this finding, a monochromator for high-pressure diffraction experiments has been designed and a source-size-limited focal spot below 10 microns is observed. As a consequence of the box-shaped rocking curve of bent Laue crystals, the focus is free of long-ranging tails. Diffraction patterns of standard powder samples were recorded on imaging plates and a theoretical description of the energy-dispersion-related peak broadening is given. Finally, diffraction patterns of N2 at 180 kbar demonstrate the excellent data quality achievable with this monochromator.

Sinapic acid ester metabolism in wild type and a sinapoylglucose-accumulating mutant of arabidopsis

Sinapoylmalate is one of the major phenylpropanoid metabolites that is accumulated in the vegetative tissue of Arabidopsis thaliana. A thin-layer chromatography-based mutant screen identified two allelic mutant lines that accumulated sinapoylglucose in their leaves in place of sinapoylmalate. Both mutations were found to be recessive and segregated as single Mendelian genes. These mutants define a new locus called SNG1 for sinapoylglucose accumulator. Plants that are homozygous for the sng1 mutation accumulate normal levels of malate in their leaves but lack detectable levels of the final enzyme in sinapate ester biosynthesis, sinapoylglucose:malate sinapoyltransferase. A study of wild-type and sng1 seedlings found that sinapic acid ester biosynthesis in Arabidopsis is developmentally regulated and that the accumulation of sinapate esters is delayed in sng1 mutant seedlings.

[The value of MRI in staging gynecologic tumors]

Traditionally gynecologic malignancies are staged by examination under anaesthesia which provides high accuracy as far as small tumors are concerned. In advanced tumors clinical staging is often inaccurate because of the difficulty to evaluate parametrial or myometrial tumor infiltration or lymphatic tumor spread. Therefore imaging modalities, such as sonography, computed tomography (CT), and magnetic resonance imaging (MRI), are required in most cases. The range of applications for MRI imaging includes staging, therapy planning, and follow-up examinations of uterine tumors and recurrent carcinoma. Based on its excellent soft tissue contrast, which allows a precise differentiation between several tissues and its direct multiplanar imaging capability, MRI is superior to sonography and CT. Only in the staging of ovarian carcinoma has the value of MRT not yet been defined, nevertheless it seems to offer diagnostic advantages over CT and sonography on account of its higher specificity. CT lose some of its value after the introduction of MRI into clinical practice. Indications for the use of CT are advanced space-occupying tumors with lymphatic spread or peritoneal implants as well as monitoring the tumor response to therapy for ovarian cancer. Sonography, as the technically simplest imaging modality, has consistently demonstrated its value as a screening method in the evaluation of benign gynecologic disease and is traditionally used for the detection of ovarian masses.

iA program package for preprocessing of two-dimensional detector data

A set of macros based on CERN's program package PAW has been developed for interactive preprocessing of two-dimensional detector data at ESRF prior to more detailed data analysis. Various types of image operations (averaging, cuts, background correction etc.) are available. The main use of the package is at present in small- and wide-angle X-ray scattering (SAXS and WAXS). The flexibility of the package allows, however, easy adaptation to other areas such as fibre or powder diffraction.

[MRT diagnosis of recurrence of gynecologic tumors]

Because of the differences in the signals from recurrent tumours and fibrosis during MRT, this method is highly suitable for differentiating between recurrent gynaecological tumours and scar formation. The value of MRT in investigating suspected recurrences was studied in 27 patients aged between 34 and 83 years. It was possible to distinguish between recurrent tumour with its high intensity signal from low signal fibrosis, using T2-weighted spin echo sequences in all cases. By means of multiplanar reconstruction and because of its high soft tissue contrast it was possible to determine the extent of tumour growth and differentiate it from surrounding tissues. With a sensitivity of 90%, specificity of 100% and accuracy of 92%, MRT is superior to all other imaging methods, including CT, in the diagnosis of tumour recurrence.

Quinidine effect on hydrosmotic response of collecting tubules to vasopressin and cAMP

Quinidine, a compound thought to increase cytosolic calcium ion activity, has been found to inhibit the hydrosmotic response to vasopressin (VP) and adenosine 3',5'-cyclic monophosphate (cAMP) in the toad urinary bladder. To test whether this drug has a similar action in the mammalian nephron, the effect of quinidine on the hydraulic conductivity of the isolated perfused rabbit cortical collecting tubule (CCT) exposed to either 20 microU/ml VP or 10(-4) M 8-(p-chlorophenylthio) - adenosine 3',5' - cyclic monophosphate (8-CPT-cAMP) was studied. Quinidine had no effect on the basal water permeability of the CCT. Quinidine sulfate (10(-4) M) reduced the VP-stimulated water permeability from 280 +/- 50 X 10(-7) to 115 +/- 41 X 10(-7) cm X s-1 X atm-1 (P less than 0.05). The hydrosmotic response to 8-CPTcAMP was likewise reduced following exposure to quinidine. This effect was shown to be dose dependent. In paired experiments, inhibition of the response to 10(-4) M 8-CPTcAMP averaged 11% at 10(-6) M, 27% at 5 X 10(-6) M, 53% at 5 X 10(-5) M, and 50% at 10(-4) M quinidine. Inhibition of the response to 8-CPTcAMP was estimated to be half maximal at approximately 5 X 10(-6) M quinidine. Tubules were protected against the quinidine-induced inhibition by the addition of 6.5 X 10(-5) M quin 2-acetoxymethylester in the presence of low peritubular Ca concentration. These results are consistent with the view that elevated cytosolic Ca ion levels inhibit the increase in water permeability elicited by VP or exogenous cAMP in the mammalian CCT.

[Continuous plasma filtration. Experiences in the treatment of pemphigus vulgaris]

By means of continuous plasmafiltration, considerable and rapid improvement could be achieved with regard to the skin lesions as well as antibody titers of a patient suffering from pemphigus vulgaris. Apart from plasmafiltration, treatment with azathioprim and steroids proved to be effective. Neither significant side effects nor infectious complications have been observed.

Cytosolic Ca2+ and Na+ activities in perfused proximal tubules of Necturus kidney

To study the role of intracellular calcium in the regulation of epithelial transport of ions and water, cytosolic calcium ion activity (aiCa) and cytosolic sodium ion activity (aiNa) were measured in cells of isolated perfused proximal tubules of Necturus kidney. aiCa was measured with Ca2+-selective microelectrodes, aiNa with Na+-selective microelectrodes. Under control conditions, i.e., Ringer solution on both sides of the epithelium, aiCa averaged 71 +/- 7 (SE) nM (n = 21) and aiNa was 12.9 +/- 0.6 mmol (n = 56). When peritubular bath sodium was reduced from 100 to 10 mM by choline substitution, aiCa increased from 73 +/- 14 to 382 +/- 69 nmol (paired t test; P less than 0.001; n = 4); in different tubules, aiNa decreased from 12.8 +/- 1.9 to 8.2 +/- 1.8 mM (P less than 0.001; n = 12). Quinidine (10(-4) M) increased aiCa from 87 +/- 19 to 556 +/- 121 nM (P less than 0.02; n = 5) but reduced aiNa from 15.1 +/- 1.2 to 11.8 +/- 0.8 mM (P less than 0.003; n = 8). In contrast, 10(-4) M ouabain increased both aiCa and aiNa; aiCa rose from 71 +/- 9 to 546 +/- 121 nmol (P less than 0.005; n = 9) and aiNa from 15.1 +/- 1.8 to 70.1 +/- 6.3 mM (P less than 0.001; n = 9). The results are consistent with the existence of a Na-Ca exchange process within the contraluminal cell membrane and with the view that increased aiCa inhibits the tubular transport of sodium by decreasing the sodium permeability of the luminal cell membrane.

pH effect on osmotic response of collecting tubules to vasopressin and 8-CPT-cAMP

The effect of peritubular and luminal pH changes on hydraulic conductance, (Lp, 10(-7) cm X s-1 X atm-1) in the isolated perfused rabbit cortical collecting tubule (CCT) was tested at 37 degrees C before and after administration of 20 microU/ml vasopressin or 10(-4) M 8-[p-chlorophenylthio]-adenosine cyclic monophosphate (8-CPT-cAMP). In vasopressin experiments when bath pH was changed from 7.58 to 7.16 or from 7.58 to 6.70, mean Lp decreased from 249 +/- 32 to 199 +/- 23 (n = 5; P less than 0.01) and from 231 +/- 38 to 201 +/- 36 (n = 5; NS), respectively. In contrast, in 8-CPT-cAMP experiments when bath [HCO3] was kept constant while CO2 was elevated the hydroosmotic response was increased. Using 2.5 mM HCO3, Lp at 0.4% CO2 was 275 +/- 15 and at 6% CO2 it was 352 +/- 50 (n = 4; paired t test; P less than 0.05). At 8.5 and 21.5 mM HCO3 raising CO2 from 2 to 13% and from 4 to 32% increased Lp from 237 +/- 71 to 410 +/- 32 (n = 4; paired t test; P less than 0.05) and from 282 +/- 45 to 449 +/- 63 (n = 6; paired t test; P less than 0.001), respectively. Reducing luminal pH from 7.40 to 5.40 had no effect on either vasopressin- or cAMP-induced changes in Lp. Accordingly, lowering the bath pH by increasing the PCO2 at constant [HCO3] markedly stimulates the response to 8-CPT-cAMP, whereas lowering the bath pH by reducing [HCO3] inhibits the vasopressin response.

Antidiuretic hormone-dependent membrane capacitance and water permeability in the toad urinary bladder

Antidiuretic hormone (ADH) increased the electrical capacitance of apical membrane of the toad bladder; this effect was modulated by the osmotic gradient across the tissue. Capacitance was measured from the transepithelial voltage response to constant-current pulses using bladders depolarized with KCl-sucrose serosal solution to reduce basolateral resistance and with Na-free mucosal solution to increase apical membrane resistance. Addition of ADH (20 mU/ml) increased capacitance by 28 +/- 9% (mean +/- SD) in the absence and by 8 +/- 3% in the presence of an osmotic gradient (200 mosM, mucosal side hypotonic). With bladders stimulated in the absence of an osmotic gradient, rapidly imposing a gradient resulted in a peak rate of water flow that declined to 40% of the peak value after 15-20 min. ADH-dependent capacitance also decreased with a similar time course. Removal of ADH reversed the capacitance change (t1/2 = 10-15 min), but the reversal was slower than the decline in water flow to basal levels (t1/2 less than 5 min). Colchicine and cytochalasin B also inhibited the ADH-induced capacitance increase. The capacitance change was also inhibited when the mucosal solution was made hypertonic with raffinose. The results are interpreted within the framework of a previously proposed model of ADH-stimulated water transport in which cytoplasmic vesicular structures fuse with the apical plasma membrane.

The role of the physician in the grief process

A child's death is a particularly painful experience for the family. The grief process involves all family members, and although it is individualized many reactions and concerns are predictable. With knowledge of the grief process, the patient's physician may be of great assistance to the family during this time of need. A plan is suggested for helping the family to cope with their feelings.

Exercise-induced release of pancreatic polypeptide and its inhibition by propranolol: evidence for adrenergic stimulation

Pancreatic polypeptide (PP) has been considered to be predominantly under cholinergic-vagal control and may therefore serve as an indicator of vagal tone. We found similar basal plasma concentrations of PP in athletes with bradycardia and in untrained subjects. We further observed that physical exercise--an adrenergic situation--induces a several-fold rise in PP plasma concentration. Maximal plasma PP levels correlated positively with maximal blood pressure. The exercise-induced rise of PP was completely abolished by propranolol. These findings suggest that stimulation of the adrenergic system releases PP and that therefore plasma PP concentrations cannot be used to determine cholinergic-vagal activity.