Vestibular neuritis: three-dimensional videonystagmography and vestibular evoked myogenic potential results

Eight patients diagnosed with vestibular neuritis received the newly developed three-dimensional videonystagmography (3D VNG) and vestibular evoked myogenic potential (VEMP) examination in order to localize the lesion site. Two (25%) of the 8 patients exhibited spontaneous nystagmus with 3 components, indicating that both the horizontal semicircular canal (HSCC) and anterior semicircular canal (ASCC) were affected. The remaining 6 patients (75%) displayed only horizontal nystagmus, meaning that only the HSCC was involved. Seven (88%) of the 8 patients had bilateral normal VEMPs, revealing sparing of the posterior semicircular canal (PSCC). In a comparative study, another seven patients with vestibular neuritis 1 year post-treatment also received the caloric test, 3D VNG and VEMP examination. Only one patient exhibited spontaneous nystagmus. An absent caloric response of the lesioned side persisted in 5 (71%) of the 7 patients. However, all patients showed normal VEMPs bilaterally. 3D VNG and VEMP examination indicates that vestibular neuritis mainly affects the superior division of the vestibular nerve, which innervates the HSCC and ASCC. Meanwhile, the function of the PSCC and saccule, innervated by the inferior vestibular nerve, is preserved.

Biologically based dose-response model for liver tumors induced by trichloroethylene

The existing extensive laboratory data on trichloroethylene (TCE) and its two metabolites, dichloroacetic (DCA) and trichloroacetic (TCA), are used to explore the relationship among these three compounds. Under the hypothesis that these compounds induce liver tumors in mice through promotion of preexisting initiated cells, it is demonstrated that DCA alone could be responsible for all the response of carcinomas in liver of B6CF(1) mice. The focus of this paper is on how a plausible biological assumption could impact on low-dose risk estimates, rather than on the risk estimate per se. The findings suggest that low-dose risk estimates to humans would be overestimated unless the different background rates between mice and humans are properly accounted for.

Dynamic expression of lunatic fringe during feather morphogenesis: a switch from medial-lateral to anterior-posterior asymmetry

Expression of Lunatic fringe mRNA was studied during feather morphogenesis and showed three stages of dynamic expression pattern. (1) Lunatic fringe was first expressed in the epithelium as a ring bordering the feather primordium when it was initially induced. (2) Shortly after, it showed a polarized pattern, first toward the lateral side of the feather primordium and then made a 90 degrees C switch toward the posterior side of the short bud. It then becomes weakly expressed in the long bud stage. (3) Finally, it is expressed in the marginal plate epithelia of feather filaments. In contrast, Radical fringe is weakly expressed in the feather bud, but is also present in the marginal plate epithelia of feather filaments.

Network approaches to two-dimensional phase unwrapping: intractability and two new algorithms

Two-dimensional (2-D) phase unwrapping, that is, deducing unambiguous phase values from a 2-D array of values known only modulo 2pi, is a key step in interpreting data acquired with synthetic aperture radar interferometry. Noting the recent network formulation of the phase unwrapping problem, we apply here some well-established ideas of network theory to formalize the problem, analyze its complexity, and derive algorithms for its solution. It has been suggested that the objective of phase unwrapping should be to minimize the total number of places where unwrapped and wrapped phase gradients differ. Here we use network constructions to show that this so-called minimum L0-norm problem is NP-hard, or one that complexity theory suggests is impossible for efficient algorithms to solve exactly. Therefore we must instead find approximate solutions; we present two new algorithms for doing so. The first uses the network ideas of shortest paths and spanning trees to improve on the Goldstein et al. residue-cut algorithm [Radio Sci. 23, 713 (1988)]. Our improved algorithm is very fast, provides complete coverage, and allows user-defined weights. With our second algorithm, we extend the ideas of linear network flow problems to the nonlinear L0 case. This algorithm yields excellent approximations to the minimum L0 norm. Using interferometric data, we demonstrate that our algorithms are highly competitive with other existing algorithms in speed and accuracy, outperforming them in the cases presented here.

In vivo fMRI demonstration of hypothalamic function following intraperitoneal glucose administration in a rat model

The hypothalamic functional MRI (fMRI) response in an animal model was studied following energy intake. Six fasted (12 h) Sprague-Dawley (SD) rats were administered an intraperitoneal injection of glucose (0.72 grams/kg body weight), while a mid-sagittal slice through the hypothalamus was continuously imaged for 60 min using a conventional T2*-weighted gradient-echo sequence. All rats demonstrated a significant acute transient decrease in the fMRI signal intensity (mean: 3.4%) in the hypothalamic region within 12-16 min after intraperitoneal glucose injection. The SD rat may be a suitable model for future fMRI studies of the hypothalamus involving the administration of exogenous nutrients and medications.

Avian integument provides multiple possibilities to analyse different phases of skin appendage morphogenesis

To analyse the morphogenic events during skin appendage formation, it is important to have an animal model that offers distinct patterns at various stages of development and is accessible to analysis using state of the art technology. The avian integument is such a model. Combining experimental embryologic approaches, organ cultures, and gene transduction technology, we are now able to begin to address the molecular basis of pattern formation, primordium initiation, anterior-posterior axis formation, proximo-distal axis formation, phenotypic determination, and others. Parallel mechanisms are usually found in feathers and hairs, and the avian integument model has matured to be a major source of new findings in the study of skin appendage morphogenesis. More information on the avian integument model can be found at website http://www.hsc.usc.educmchuong.

Lack of effect of dietary alpha-tocopherol on chemically induced hepatocarcinogenesis in rats

We investigated the effects of alpha-tocopherol on diethylnitrosamine (DEN) initiation-phenobarbital (PB) promotion of hepatic foci in female Sprague-Dawley rats. Groups of eight rats were initiated with DEN (15 mg/kg) at 24 hours of age. After weaning, they received diets containing 500 ppm PB and various concentrations of alpha-tocopherol, deficient (0 ppm), adequate (100 ppm), and supplemented (5,000 ppm), for 24 weeks. Rats fed alpha-tocopherol-supplemented diets had significantly greater hepatic alpha-tocopherol levels than those fed alpha-tocopherol-deficient or -adequate diets (p < 0.05). Liver lipid peroxidation (measured as thiobarbituric acid-reactive substances) was significantly greater in rats fed alpha-tocopherol-deficient diets than in those fed alpha-tocopherol-adequate or -supplemented diets (p < 0.05). The dietary alpha-tocopherol level had no significant effect on the ratios of reduced glutathione (GSH) to oxidized GSH or reduced GSH to total GSH in the liver or on the plasma prostaglandin E2 concentration or on the activities of hepatic cytosolic and particulate protein kinase C. Rats fed alpha-tocopherol-adequate or -supplemented diets had significantly greater hepatic glutathione S-transferase, GSH reductase, and GSH peroxidase activities than those fed alpha-tocopherol-deficient diets (p < 0.05). The dietary alpha-tocopherol level did not significantly affect the formation of hepatic gamma-glutamyl transpeptidase- and placental glutathione S-transferase-positive foci. These results suggest that alpha-tocopherol does not influence hepatic foci formation and that reactive oxygen species may not be the underlying mechanism of hepatic foci formation in this DEN initiation-PB promotion model of hepatocarcinogenesis.

Varicella pneumonia complicated by acute respiratory distress syndrome in an adult

Primary varicella infection is uncommon in adults, but carries a higher rate of morbidity and mortality than in children. Pneumonia is the most common complication of primary varicella infection in adults. However, varicella pneumonia complicated with acute respiratory distress syndrome (ARDS) is very rare. We report a case of ARDS secondary to varicella pneumonia in a 26-year-old man with primary varicella. The patient was otherwise healthy and had no evidence of human immunodeficiency virus infection. The initial chest radiograph showed bilateral reticulonodular infiltrates, which quickly evolved to diffuse alveolar consolidations. Arterial blood gas analysis revealed a ratio of arterial partial pressure to fraction of inspired oxygen of 87. Abnormal liver function and thrombocytopenia were also noted. Treatment consisted of mechanical ventilatory support and intravenous administration of acyclovir. His pulmonary condition gradually improved and he was successfully weaned from the ventilator 1 week later. He was discharged on the 15th hospital day with a favorable outcome. His pulmonary function improved progressively, with normal spirometry and lung volumes, but persistent mild impairment of diffusing capacity, 6 months after discharge.

Toxic effects of mitomycin-C on cultured corneal keratocytes and endothelial cells

Improper use of mitomycin-C in ocular medication may result in damage to corneal cells. In this study, the toxic effects of mitomycin-C on cultured porcine keratocytes and endothelial cells were estimated by MTT, 3H-thymidine uptake and cellular counting assay methods. It was found that mitomycin-C caused a dose-dependent toxic effect to keratocytes and endothelial cells. Both cells were treated with mitomycin-C at the concentration ranging from 100, 10, 1, 0.1 to 0.01 microg/ml for 3 min, 5 min or 100 min. The 50% inhibitory dose (ID50) of mitomycin-C to keratocytes and endothelial cells as measured by MTT assay was 0.40, 0.18, 0.16 mg/ml and 0.27, 0.15, 0.14 mg/ml, respectively, after 3, 5 and 100 minutes drug treatment. The ID50 for keratocytes and endothelial cells as measured by 3H-thymidine uptake immediately, 1 day and 7 days after 100 minutes mitomycin-C treatment was 0.3, 0.0002, 143.2 microg/ml and 45.1, 101.1, 450.2 microg/ml, respectively. The ID50 for keratocytes and endothelial cells as measured by cellular counting 1 day and 7 days after mitomycin-C treatment was 232.5, 109.7 microg/ml and 239.9, 367.5 microg/ml, respectively. It is concluded that mitomycin-C is more toxic to cellular proliferation in cultured corneal keratocytes than in endothelial cells.

Time course of pharmacological modulation of peak eosinophilic airway inflammation after mite challenge in guinea pigs: a therapeutic approach

BACKGROUND

It is well known that eosinophilic airway inflammation develops after allergen challenge in sensitized humans and animals. However, the detailed time course of suppression of early eosinophilic airway inflammation by pharmacological agents given just after challenge has not been discussed. Therefore, we aimed to evaluate the time course relationship of the suppression of peak eosinophilia by anti-cytokines and pharmacological agents given several hours after the aerosol challenge by a therapeutic approach.

METHODS

We used crude mite extract as an allergen to create a sensitization and inhalation challenge, and performed bronchoalveolar lavages (BAL) after the inhalation challenge to observe the degree of eosinophilic airway inflammation in guinea pigs. Various anti-cytokines (anti-IL-3 and anti-IL-5) and pharmacological agents (dexamethasone, theophylline, and roxithromycin) were given within several hours after the acute aeorosol challenge to evaluate the suppressive effect on peak eosinophilia in BAL fluid, which occurred 24 h after the challenge.

RESULTS

Our results show that anti-IL-5 and dexamethasone, given within 4 and 8 h after the inhalation challenge, respectively, inhibit the acute allergen-induced peak eosinophilia in BAL fluid. However, anti-IL-3, theophylline, and roxithromycin had no effect on peak eosinophilic airway inflammation after challenge.

CONCLUSION

These observations suggest that several hours are needed to complete the process of cytokine-induced recruitment of eosinophils from the blood to the airways after acute allergen challenge. This may be the optimal time to administer anti-cytokines and dexamethasone to attenuate the subsequent eosinophilic airway inflammation after acute allergen-induced asthmatic attacks.

Effects of N(omega)-nitro-L-arginine (L-NOARG) on blood flow and vasomotion in rat diaphragm microcirculation during hemorrhagic hypotension

The role of N(omega)-nitro-L-arginine (L-NOARG), a nitric oxide (NO) synthase inhibitor, in the control of blood flow and vasomotion in rat diaphragm microcirculation during hemorrhagic hypotension was investigated by means of laser Doppler flowmetry (LDF). Fifty-six Sprague-Dawley rats were divided into seven groups. Ten minutes after one-stage hemorrhage to 40-60% of initial blood pressure, the rats received 15 min topical superfusion of saline (group 1, time control), 0.1 mM L-NOARG (group 2), 10 mM L-arginine (group 3), or vehicle (0.1% DMSO and 0.9 mN NaOH, group 4). For groups 5 and 6, L-NOARG or its vehicle was superfused for 15 min without hemorrhage. In group 7, the vasodilator responses to the endothelium-dependent vasorelaxant acetylcholine (ACH) and the endothelium-independent vasorelaxant sodium nitroprusside (SNP) were assessed at rest and after 25 min of hemorrhagic hypotension. The results showed no significant differences in blood flow, fundamental frequency, or relative amplitude of the rat diaphragm microcirculation before or after administration of the test agents among the first four groups during hemorrhagic hypotension or in groups 5 and 6 during sham operation without hypoperfusion. Hemorrhagic hypotension significantly decreased the vasodilator response to ACH (p = 0.003), but not to SNP. We conclude that NO did not play an important role in the regulation of blood flow or vasomotion in rat diaphragm microcirculation during acute hemorrhagic hypotension.

Wnt-7a in feather morphogenesis: involvement of anterior-posterior asymmetry and proximal-distal elongation demonstrated with an in vitro reconstitution model

How do vertebrate epithelial appendages form from the flat epithelia? Following the formation of feather placodes, the previously radially symmetrical primordia become anterior-posterior (A-P) asymmetrical and develop a proximo-distal (P-D) axis. Analysis of the molecular heterogeneity revealed a surprising parallel of molecular profiles in the A-P feather buds and the ventral-dorsal (V-D) Drosophila appendage imaginal discs. The functional significance was tested with an in vitro feather reconstitution model. Wnt-7a expression initiated all over the feather tract epithelium, intensifying as it became restricted first to the primordia domain, then to an accentuated ring pattern within the primordia border, and finally to the posterior bud. In contrast, sonic hedgehog expression was induced later as a dot within the primordia. RCAS was used to overexpress Wnt-7a in reconstituted feather explants derived from stage 29 dorsal skin to further test its function in feather formation. Control skin formed normal elongated, slender buds with A-P orientation, but Wnt-7a overexpression led to plateau-like skin appendages lacking an A-P axis. Feathers in the Wnt-7a overexpressing skin also had inhibited elongation of the P-D axes. This was not due to a lack of cell proliferation, which actually was increased although randomly distributed. While morphogenesis was perturbed, differentiation proceeded as indicated by the formation of barb ridges. Wnt-7a buds have reduced expression of anterior (Tenascin) bud markers. Middle (Notch-1) and posterior bud markers including Delta-1 and Serrate-1 were diffusely expressed. The results showed that ectopic Wnt-7a expression enhanced properties characteristic of the middle and posterior feather buds and suggest that P-D elongation of vertebrate skin appendages requires balanced interactions between the anterior and posterior buds.

Predicting factors for outcome of tube thoracostomy in complicated parapneumonic effusion for empyema

STUDY OBJECTIVES

To determine the predicting factors for outcome of tube thoracostomy in patients with complicated parapneumonic effusion (CPE) or empyema.

DESIGN AND SETTINGS

Retrospective chart review over a 55-month period at a tertiary referred medical center.

PATIENTS AND MEASUREMENTS

The medical charts of patients with empyema or CPE were reviewed. Data including age, gender, clinical symptoms, important underlying diseases, leukocyte count, duration of preadmission symptoms, interval from first procedure to second procedure, the time from first procedure to discharge (recovery time), the amount of effusion drained, administration of intrapleural streptokinase, chest tube size and position, loculation of pleural effusion, and characteristics and culture results of pleural effusion were recorded and compared between groups of patients with successful and failed outcome of tube thoracostomy drainage.

RESULTS

One hundred twenty-one patients were selected for study. One hundred of these patients had received tube thoracostomy drainage with 53 successful outcomes and 47 failed outcomes of chest tube drainage. Nineteen patients received decortication directly, and the other two received antibiotics alone. Univariate analysis showed that pleural effusion leukocyte count, effusion amount, and loculation of pleural effusion were significantly related to the outcome of chest tube drainage. Multiple logistic regression analysis demonstrated that loculation and pleural effusion leukocyte count < or = 6,400/uL were the only independent predicting factors related to failure of tube thoracostomy drainage.

CONCLUSIONS

Loculation and pleural effusion leukocyte count < or = 6,400/microL were independent predicting factors of poor outcome of tube thoracostomy drainage. These results suggest that if the initial attempt at chest tube drainage fails, early surgical intervention should be considered in good surgical candidates with loculated empyema or pleural effusion with leukocyte count < or = 6,400/microL.

The nephritogenic T cell response in murine chronic graft-versus-host disease

To investigate mechanisms of cell-mediated events in chronic glomerulonephritis, T cell clones were isolated from kidneys of animals with murine chronic graft-vs-host disease. This systemic disorder is induced in normal (C57BL/6 x DBA/2)F1 recipients (H-2b/d) following transfer of parental (DBA/2) T cells (H-2d). These studies demonstrate that mouse renal (MR) T cells isolated from nephritic kidneys of diseased recipients are host-derived CD4+ alpha/beta+ T cells. Adoptive transfer of a panel of MR clones to naive (C57BL/6 x DBA/2)F1 recipients reveals distinct functional subsets. One subset does not transfer renal disease, and one induces severe renal inflammation and damage. In vitro proliferative responses of nephritogenic MR clones reveal predominant reactivity toward autologous class II MHC (I-Ed/I-Ad) determinants, and selected nephritogenic MR clones preferentially recognize renal Ag preparations derived from normal (C57BL/6 x DBA/2)F1 kidneys. In addition, cytokine profile analysis of MR clones indicates a Th2 pattern with IL-4 and IL-10 expression, although nephritogenic T cell clones also express IFN-gamma. These data suggest that the nephritogenic T cell response in chronic graft-vs-host disease is autoreactive in nature and may be restricted by determinants shared by both graft and host (Iad).

Subtalar distractional realignment arthrodesis with wedge bone grafting and lateral decompression for calcaneal malunion

BACKGROUND

The purpose of this study was to evaluate prospectively the efficacy of subtalar distractional realignment arthrodesis in the treatment of calcaneal malunion associated with subtalar arthritis, collapse of height, talonavicular subluxation, malalignment of the heel axis, and widening heel with calcaneofibular abutment.

METHODS

Thirty-four patients with severe calcaneal malunion were treated with a lateral approach, lateral decompression, medial subtalar capsulotomy, and distraction and realignment of the subtalar joint with an anteriorly and laterally tapered wedge bone graft. The patients were evaluated with a functional rating scale and radiographs, both before and after surgery.

RESULTS

Thirty-two of the 34 patients were evaluated at a mean of 71 months (range, 60-92 months) after the arthrodesis. Solid subtalar fusion was achieved in 31 of the 32 patients. The average gain of subtalar distraction was 12 mm. Neutral or mild valgus alignment was achieved in 26 of the 32 patients. The mean postoperative score (83) showed significant improvement over the mean preoperative score (47). Overall, the functional rating scale revealed excellent or good results in 26 patients and fair results in 6 patients.

CONCLUSION

Coupled with wedge bone grafting, the subtalar distractional realignment arthrodesis achieved restoration of hindfoot height and axial alignment with a good union rate and significant improvement in the majority of patients with calcaneal malunion.

The telomeres of Streptomyces chromosomes contain conserved palindromic sequences with potential to form complex secondary structures

The chromosomes of the gram-positive soil bacteria Streptomyces are linear DNA molecules, usually of about 8Mb, containing a centrally located origin of replication and covalently bound terminal proteins (which are presumably involved in the completion of replication of the telomeres). The ends of the chromosomes contain inverted repeats of variable lengths. The terminal segments of five Streptomyces chromosomes and plasmids were cloned and sequenced. The sequences showed a high degree of conservation in the first 166-168bp. Beyond the terminal homology, the sequences diverged and did not generally cross-hybridize. The homologous regions contained seven palindromes with a few nucleotide differences. Many of these differences occur in complementary pairs, such that the palindromicity is preserved. Energy-optimized modelling predicted that the 3' strand of the terminal palindromes can form extensive hairpin structures that are similar to the 3' ends of autonomous parvovirus genomes. Most of the putative hairpins have a GCGCAGC sequence at the loop, with the potential to form a stable single C-residue loop closed by a sheared G:A pairing. The similarity between the terminal structures of the Streptomyces replicons and the autonomous parvoviral genomes suggests that they may share some structural and/or replication features.

Photochemical reactions of flavor compounds

Photochemical reaction is a chemical reaction which is initiated by light. In addition to light, photosensitizer and oxygen are the two important factors which contribute to the formation of photochemical products. In this contribution, photochemical reactions of flavor compounds are classified into four categories according to the factors of photosensitizer and oxygen. Photochemical reaction with or without sensitizer in the absence of oxygen and unsensitized photochemical reaction in the presence of oxygen usually involve free radical reactions; while in the presence of oxygen and sensitizer, the singlet oxygen can be generated that then reacts with flavor compounds which contain double bonds to give the oxygenated products.

Respiratory mechanics before and after hemodialysis in mechanically ventilated patients

Hemodialysis, which leads to negative fluid balance, is often required in mechanically ventilated patients with renal failure. We conducted a prospective study on the influence of hemodialysis on the respiratory mechanics in 14 mechanically ventilated patients (10 men, 4 women, mean age 70.1 +/- 8.1 yr) with various causes of renal failure requiring hemodialysis in an intensive care unit. Respiratory mechanics were measured before and after hemodialysis using the interrupter technique under constant flow and constant volume. The values of several parameters of respiratory mechanics were significantly lower after hemodialysis: peak airway pressure (26.97 +/- 4.62 vs 23.45 +/- 4.13 cmH2O), airway pressure at zero flow (23.81 +/- 4.18 vs 21.50 +/- 3.79 cmH2O), airway plateau pressure (18.56 +/- 3.70 vs 16.48 +/- 3.07 cmH2O), and intrinsic positive end-expiratory pressure (4.03 +/- 2.90 vs 2.65 +/- 1.84 cmH2O). Minimal respiratory resistance and maximal respiratory resistance were significantly decreased after hemodialysis (4.38 +/- 1.26 vs 2.99 +/- 1.00 cmH2O/L/s and 9.93 +/- 2.50 vs 8.39 +/- 2.43 cmH2O/L/s, respectively), but effective additional respiratory resistance and static respiratory compliance were not. Significant correlations were found between body weight reduction by hemodialysis and changes in minimal respiratory resistance (r = 0.758, p < 0.01), maximal respiratory resistance (r = 0.544, p < 0.05), and static respiratory compliance (r = 0.703, p < 0.01). We conclude that hemodialysis significantly alters the respiratory mechanics in mechanically ventilated renal failure patients and that the alteration may be related to the negative fluid balance caused by hemodialysis.

The role of phosphorylation in human estrogen receptor function

We have studied the role of phosphorylation of the human estrogen receptor (hER) at serine 118, which has been previously identified as a site important for transactivation. We have tested this transactivation in yeast and cell-free transcription assays, and have shown that mutation of serine 118 to alanine results in a 30-40% decrease in hER-dependent transcription. Furthermore, we investigated the functional significance of phosphorylation at this site by hormone binding and DNA binding. The mutation of serine 118 to alanine in the hER caused no decrease in its affinity for either estradiol or an ERE. The mutant receptor had an altered phosphorylation pattern when expressed in COS-1 and Sf9 cells, but not in HeLa cells. Our findings indicate that phosphorylation of serine 118 of the hER plays a role in regulating its transcriptional activity.

Thermal Degradation of Allyl Isothiocyanate in Aqueous Solution

Allyl isothiocyanate in an aqueous solution was heated and refluxed at 100 degrees C for 1 h. The reaction mixtures were then extracted with methylene chloride and analyzed using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The mixtures in aqueous phase were analyzed by high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) equipped with an atmospheric-pressure chemical ionization (APCI) interface. The compounds identified in the methylene chloride extracts included diallyl sulfide, diallyl disulfide, diallyl trisulfide, diallyl tetrasulfide, allyl thiocyanate, 3H-1,2-dithiolene, 2-vinyl-4H-1,3-dithiin, 4H-1,2,3-trithiin, and 5-methyl-1,2,3,4-tetrathiane. N,N'-Diallylthiourea, which was the major degradation product in the aqueous phase from the thermal reaction of allyl isothiocyanate, was identified by using LC-MS (APCI+), direct-probe EI-MS, and (1)H-NMR. The possible mechanism for the formation of these products was proposed.

Image segmentation via adaptive K-mean clustering and knowledge-based morphological operations with biomedical applications

Image segmentation remains one of the major challenges in image analysis. In medical applications, skilled operators are usually employed to extract the desired regions that may be anatomically separate but statistically indistinguishable. Such manual processing is subject to operator errors and biases, is extremely time consuming, and has poor reproducibility. We propose a robust algorithm for the segmentation of three-dimensional (3-D) image data based on a novel combination of adaptive K-mean clustering and knowledge-based morphological operations. The proposed adaptive K-mean clustering algorithm is capable of segmenting the regions of smoothly varying intensity distributions. Spatial constraints are incorporated in the clustering algorithm through the modeling of the regions by Gibbs random fields. Knowledge-based morphological operations are then applied to the segmented regions to identify the desired regions according to the a priori anatomical knowledge of the region-of-interest. This proposed technique has been successfully applied to a sequence of cardiac CT volumetric images to generate the volumes of left ventricle chambers at 16 consecutive temporal frames. Our final segmentation results compare favorably with the results obtained using manual outlining. Extensions of this approach to other applications can be readily made when a priori knowledge of a given object is available.

Dose-response relationship and irreversible obstructive ventilatory defect in patients with consumption of Sauropus androgynus

STUDY OBJECTIVES

To determine the dose-response aspect of pulmonary function impairment in patients with consumption of Sauropus androgynus for weight reduction.

METHODS

A questionnaire and pulmonary function tests were performed in 194 patients with a history of consumption of S androgynus with or without chest symptoms. Patients with obstructive ventilatory defect received follow-up spirometry 22 to 24 months after beginning consumption of the vegetable.

RESULTS

Data from 178 patients were analyzed. Patients generally consumed 150 g of S androgynus daily as raw juice (60.7%), sauteed (16.9%), mixed preparation (20.8%), or boiled (1.7%) for various periods of time. We divided patients into five groups according to the total dose consumed (group A, 0 to 1,799 g; group B, 1,800 to 3,599 g; group C, 3,600 to 5,399 g; group D, 5,400 to 7,199 g; and group E, > or =7,200 g). The frequency of obstructive ventilatory defect was higher in the high-dose group than in the low-dose group (A, 4/43=9.3%; B, 13/64=20.3%; C, 14/32=43.8%; D, 5/12=41.7%; and E, 13/27=48.1%; p < 0.01). In total, 49 patients (27.5%) had moderate to severe obstructive ventilatory defects without bronchodilator response. The FEV1 and FEV1 percent predicted in these 49 patients were 0.96+/-0.38 L (mean+/-SD) and 41.8+/-16.9%, respectively. Sixty-five percent of these 49 patients began to suffer from dyspnea in the third, fourth, or fifth month after taking the vegetable and no patient began to develop dyspnea later than 7 months after beginning consumption of the vegetable. Using stepwise multiple regression, we found that the FEV1 percent predicted was negatively associated with the total dose ingested (r=0.24, p < 0.01). Follow-up spirometry showed that the obstructive ventilatory defect was irreversible in all patients.

CONCLUSIONS

Consumption of S androgynus can result in moderate to severe obstructive ventilatory defect within 7 months, and the disorder was irreversible in the observation period for 22 months.

Transforming growth factor beta1 attenuates ceramide-induced CPP32/Yama activation and apoptosis in human leukaemic HL-60 cells

Ceramide, a product of sphingomyelin turnover, is a novel lipid second messenger that mediates important cellular functions including proliferation, differentiation and apoptosis. This study demonstrates that the CPP32/Yama protease was activated during apoptosis induced by the membrane-permeable second messenger C2-ceramide in HL-60 cells. We also found that the addition of a specific tetrapeptide inhibitor of CPP32/Yama, Ac-DEVD-CHO, provided an effective protection against ceramide-induced cell death. These results suggested that CPP32/Yama has a central role in ceramide-mediated apoptosis. Furthermore a wide variety of cytokines were examined for their effect on ceramide-induced apoptosis. Only transforming growth factor beta1 (TGF-beta1) (1 ng/ml) exerted significant prevention of apoptosis induced by C2-ceramide, or by sphingomyelinase (increases intracellular ceramide). Consistently, TGF-beta1 abrogated the cleavage of poly(ADP-ribose) polymerase and the production of the CPP32/Yama active subunit, p17. However, TGF-beta1 treatment did not cause growth inhibition or alter the level of cyclin-dependent kinase inhibitor p27. It suggests that the preventive effect of TGF-beta1 is not mediated by growth arrest. Interestingly, we found that TGF-beta1 prevented the C2-ceramide-caused decrease of Bcl-2 protein. We thus propose that TGF-beta1 rescues ceramide-induced cell death, possibly by maintaining the constant level of Bcl-2, thereby abolishing CPP32/Yama protease activation.

Instability of artificially circularized chromosomes of Streptomyces lividans

The chromosomes of Streptomyces species are linear molecules, containing long terminal inverted repeats and covalently bound terminal proteins. These chromosomes undergo spontaneous deletions of the terminal sequences at high frequencies and become circularized in several cases examined. Artificial circularization of the Streptomyces lividans chromosome was also achieved by targeted recombination in vivo, in which the terminal inverted repeats of the chromosome were connected by a kanamycin resistance gene (aphII). Under kanamycin selection, the circularized chromosomes harboured tandem amplifications of a 20.2 kb sequence that included the aphII gene flanked by direct repeats and deletions nearby. On release from kanamycin selection, the aphII amplifications and the neighbouring sequences were deleted from the chromosomes, rendering all the cultures kanamycin sensitive. The chloramphenicol resistance gene, which was prone to deletion in wild-type S. lividans, became much more stable in the kanamycin-sensitive derivatives. These results indicate that the telomeres and/or certain terminal sequences may be involved in the structural instability of Streptomyces chromosomes.