Stresses at the cervical lesion of maxillary premolar--a finite element investigation

OBJECTIVES

The objective of this study was to use a three-dimensional (3-D) finite element model to investigate normal stress distribution to substantiate the tooth flexure mechanism. The study also compared the changes in the stresses by different occlusal loading sites and directions.

METHODS

The 3-D finite element analysis was used. A maxillary premolar was selected to construct the simulation model. The model was constructed step-by-step for convergence and validity. Seven load conditions for various load sites and different directions were simulated to the model.

RESULTS

The maximal principal stress and minimal principal stress distributions developed within the structures of seven load conditions were output and their stress distributions on z-plane at the vertical midline were shown. The peak tensile stress of the cervical area for various load conditions were compared and listed.

CONCLUSIONS

This study has shown that the presence of tensile stresses in the cervical region of a maxillary premolar by various loading sites and different directions. The results coincided with the stress-induced theory, hence sustaining it. The relationship of the affected factors of leverage to the development of cervical abfraction lesions, was explored.

Layered perovskites with giant spontaneous polarizations for nonvolatile memories

A series of titanate-based layered perovskites having large values of the spontaneous polarization P(s) were developed for their applcations to nonvolatile ferroelectric random access memories. Among these, the Nd-modified bismuth titanate [Bi(4-x)Nd(x)Ti(3)O(12) (BNdT)] system exhibited the most remarkable ferroelectric properties. The c-axis oriented BNdT capacitor was characterized by a switchable remanent polarization 2P(r) of over 100 microC/cm(2) and imprinting and fatigue-free behavior. The active Ti site responsible for the giant P(s) was identified with the help of Rietveld analysis, x-ray absorption near-edge structure study, and ab initio quantum computations.

Peripheral blood lymphocyte transformation to G2s in patients with autoimmune thyroid disease with and without ophthalmopathy

Thyroid associated ophthalmopathy (TAO) is an autoimmune disease involving the extra ocular muscles and surrounding orbital connective and adipose tissues. The mechanism for the link between ophthalmopathy and thyroid autoimmunity is unknown but current evidence favors an immune reaction against a thyroid and orbital tissue shared antigen such as the novel protein G2s, which is highly expressed in both eye muscles and thyroid, or the TSH receptor (TSHR). Earlier, we showed that serum antibodies against G2s were closely linked to ophthalmopathy. Although lymphocytic infiltration of the eye muscles is a pathologic feature of TAO, it is unclear whether the reaction is in the eye muscle fiber or the surrounding connective tissue. We tested for peripheral blood mononuclear cell sensitization to G2s fusion protein in patients with TAO, Graves' hyperthyroidism or Hashimoto's thyroiditis without evident ophthalmopathy and normal subjects. Results were expressed as counts per min (cpm) and as stimulation indices (SI). Although proliferation tests were positive in 23% of patients with TAO, overall, there were no significant differences between the four groups. Tests were also positive in four out of seven patients with Hashimoto's thyroiditis, suggesting that immune reactivity against G2s could be a marker of this progressive thyroid disorder. There was no significant correlation between T cell reactivity to G2s and serum antibodies against the same protein, measured in enzyme linked immunosorbent assay. Failure to demonstrate significant T lymphocyte sensitization to G2s in the majority of patients with TAO may reflect the small number of sensitized T cells expected to be circulating in the peripheral blood which could be overcome by testing cloned orbital T cells, as available. Another possibility is that the T cell epitope(s) is not present on the 141 amino acid fragment of G2s that we have so far cloned. The finding of positive T cell tests in a small proportion of patients with ophthalmopathy suggests that future studies using cloned orbital T cells and full length G2s, or its dominant epitope, are indicated.

Unicameral bone cysts treated by injection of bone marrow or methylprednisolone

In 79 consecutive patients with unicameral bone cysts we compared the results of aspiration and injection of bone marrow with those of aspiration and injection of steroid. All were treated by the same protocol. The only difference was the substance injected into the cysts. The mean radiological follow-up to detect activity in the cyst was 44 months (12 to 108). Of the 79 patients, 14 received a total of 27 injections of bone marrow and 65 a total of 99 injections of steroid. Repeated injections were required in 57% of patients after bone marrow had been used and in 49% after steroid. No complications were noted in either group. In this series no advantage could be shown for the use of autogenous injection of bone marrow compared with injection of steroid in the management of unicameral bone cysts.

Cross-cultural validation of an international questionnaire, the General Measure of the Functional Assessment of Cancer Therapy scale (FACT-G), for Japanese

The General Measure of the Functional Assessment of Cancer Therapy scale (FACT-G) was developed in an English-speaking culture (USA). To determine if FACT-G could be used in Japan, a cross-cultural validation was performed. The Japanese version was created through an iterative forward-backward translation sequence used throughout the FACT multi-lingual translation project. In evaluating psychometric testing, its construct validity was investigated by factor analysis and multi-trait scaling analysis. Clinical validity was estimated by known-groups comparison using stage, performance score (PS) and patient location, and validated longitudinally by PS. The FACT-G (version 3) was given to 180 patients with lung cancer. Analyses showed that the scales of Physical, Functional, Emotional Well-Being, and Relationship with Doctors were constructively valid in Japan. Japanese patients felt that familial relationships were different than those with friends and neighbors, indicating that the Social/Family Well-Being scale needed cultural adaptation. Two items concerning coping with illness and acceptance of illness did not load predictably onto their respective scales and were considered to be cross-culturally problematic. However, clinical validity demonstrated its sensitivity. Japanese version 4 has been improved to address the weakness in an attempt to become an instrument that is applicable across cultures.

Thin-plate spline (TPS) graphical analysis of the mandible on cephalometric radiographs

We describe two cases of Class III malocclusion with and without orthodontic treatment. A thin-plate spline (TPS) analysis of lateral cephalometric radiographs was used to visualize transformations of the mandible. The actual sites of mandibular skeletal change are not detectable with conventional cephalometric analysis. These case analyses indicate that specific patterns of mandibular transformation are associated with Class III malocclusion with or without orthopaedic therapy, and visualization of these deformations is feasible using TPS graphical analysis.

Reduction in erythropoietin doses by the use of chronic intravenous iron supplementation in iron-replete hemodialysis patients

BACKGROUND

Iron deficiency is the most common cause of suboptimal response to recombinant human erythropoietin (rHuEPO) in chronic hemodialysis (HD) patients. Iron supply can correct this situation, however, optimal dosage, route of administration, and monitoring of iron status during rHuEPO therapy in maintenance HD patients remains controversial.

METHODS

We conducted a 12-month intravenous iron substitution trial in 149 iron-replete chronic HD patients receiving subcutaneous rHuEPO therapy. The available iron pool was maintained with 100 mg iron every 2 weeks or 1 month depending on serum ferritin and transferrin saturation levels, the rHuEPO dosage titrated depending on hematocrit (Hct) levels.

RESULTS

After 12-month protocol, the Hct increased (28.7 +/- 4.1 vs 27.7 +/- 2.6, p = 0.003), rHuEPO requirement reduced 25% (46.1 +/- 28.9 vs 61.5 +/- 67.8 U/kg/week, p = 0.006), serum ferritin increased (1,383 +/- 727 vs 930 +/- 857 ng/ml, p < 0.001), so did the transferrin saturation (36.1 +/- 12.7 vs 27.5 +/- 12.8%, p < 0.001). The serum albumin decreased slightly but reached statistical significance (4.1 +/- 0.48 vs 4.2 +/- 0.36 g/dl, p = 0.006), so did the cholesterol levels (166 +/- 41 vs 173 +/- 38 mg/dl, p = 0.044) and pre-dialysis creatinine (11.3 +/- 2.3 vs 11.5 +/- 2.4 mg/dl, p = 0.015). Besides, the iPTH levels did not interfere with the rHuEPO dosage reduction and Hct increment in our patients.

CONCLUSION

We conclude that maintaining high levels of serum ferritin and transferrin saturation could further reduce the requirement of rHuEPO in chronic HD patients, but the long-term effect of iron overloading to patients' nutritional status must be further evaluated in contrast to the economic saving.

Evaluating the total costs of chemotherapy-induced toxicity: results from a pilot study with ovarian cancer patients

PURPOSE

While chemotherapy-related toxicities affect cancer patients' activities of daily living and result in large expenditures of medical care for treatment, few studies have assessed the out-of-pocket and indirect costs incurred by patients who experience toxicity. The objective of this study was to evaluate the feasibility of obtaining detailed and comprehensive cost information from patients who experienced neutropenia, thrombocytopenia, or neurotoxicity during treatment.

METHODS

Ovarian cancer patients who experienced chemotherapy-associated hematologic or neurologic toxicities were asked to record detailed information about hospitalization, laboratories, physician visits, phone calls, home visits, medication, medical devices, lost productivity, and caregivers. Resource estimates were converted into cost units, with direct medical cost estimates based on hospital cost-accounting data and indirect costs (i.e., productivity loss) on modified labor force, employment, and earnings data.

RESULTS

Direct medical costs were highest for neutropenia (mean of $7,546/episode), intermediate for thrombocytopenia (mean of $3,268/episode), and lowest for neurotoxicity (mean of $688/episode). Indirect costs relating to patient and caregiver work loss and payments for caregiver support were substantial, accounting for $4,220, $3,834, and $4,282 for patients who developed neurotoxicity, neutropenia, and thrombocytopenia, respectively. The total costs of chemotherapy-related neurotoxicity, neutropenia, and thrombocytopenia were $4,908, $11,830, and $7,550.

CONCLUSION

Our study has shown that, with the assistance of patients who are experiencing toxicity, estimation of the total costs of cancer-related toxicities is feasible. Indirect costs, while not included in prior estimates of the costs of toxicity studies, accounted for 34% to 86% of the total costs of cancer supportive care.

Translation and validation of the Functional Assessment of Cancer Therapy-Bone Marrow Transplant (FACT-BMT) Version 4 quality of life instrument into traditional Chinese

The need for a culturally sensitive instrument to assess quality of life (QOL) of patients in international oncology clinical trials has been well documented. This study was designed to evaluate the psychometric properties of the traditional Chinese translation (TCHI) of the Functional Assessment of Cancer Therapy-Bone Marrow Transplant (FACT-BMT) Version 4. The FACT-BMT consists of the FACT-General and treatment-specific concerns of bone marrow transplantation. The Chinese translation follows the standard Functional Assessment of Chronic Illness Therapy (FACIT) translation methodology. Bilingual teams from the United States and Hong Kong reviewed the translation to develop a provisional TCHI FACT-BMT, which was then pre-tested by interviewing 20 native Chinese-speaking BMT patients in Hong Kong. The pre-test results indicated good content coverage and overall comprehensibility. A refined translation, taking into account patient comments, was validated by 134 BMT patients in Hong Kong. The results indicated the high internal consistency of the TCHI FACT-BMT scales, with Cronbach's alpha coefficients ranging from 0.71 (emotional well-being) to 0.92 (FACT-BMT total). The FACT-BMT also demonstrated good construct validity when correlated with SF-36 Health Survey scales. The QOL of Chinese BMT patients can now be evaluated using a well-validated international QOL instrument in their own language.

17beta-estradiol inhibits soluble guanylate cyclase activity through a protein tyrosine phosphatase in PC12 cells

Besides its involvement in reproductive functions, estrogen protects against the development of cardiovascular diseases. The guanylate cyclase/cGMP system is known to exert potent effects on the regulation of blood pressure and electrolyte balance. We examined whether 17beta-estradiol can affect soluble guanylate cyclase in PC12 cells. The results indicate that 17beta-estradiol decreases cGMP levels in PC12 cells. 17beta-Estradiol decreases sodium nitroprusside (SNP)-stimulated, but not atrial natriuretic factor-stimulated cGMP formation in PC12 cells, indicating that 17beta-estradiol decreases cGMP levels by inhibiting the activity of soluble guanylate cyclase. 17beta-Estradiol also stimulates protein tyrosine phosphatase activities in PC12 cells and dephosphorylates at least three proteins. Addition of sodium vanadate, a protein tyrosine phosphatase inhibitor, blocks the inhibitory effects of 17beta-estradiol on soluble guanylate cyclase activity in PC12 cells. Furthermore, transfection of SHP-1, a protein tyrosine phosphatase, into PC12 cells inhibits both basal and SNP-stimulated guanylate cyclase activity. Amino acid analysis also reveals that the 70-kDa subunit of soluble guanylate cyclase contains the SHP-1 substrate consensus sequence. These results suggest that 17beta-estradiol inhibits soluble guanylate cyclase activity through SHP-1.

The Spanish National Institutes of Health-Chronic Prostatitis Symptom Index: translation and linguistic validation

PURPOSE

The prominence of health related quality of life end points in international clinical research underscores the importance of well validated and translated measures to enable cross-cultural comparison. The National Institutes of Health (NIH)-Chronic Prostatitis Symptom Index (CPSI) assesses symptoms and health related quality of life in men with chronic nonbacterial, NIH type III prostatitis. To expand its use to Spanish speaking patients we performed a translation and linguistic validation.

MATERIALS AND METHODS

The 9-item NIH-CPSI was translated into Spanish according to a standard methodology of 2 forward translations, 1 reconciled version, back translation of the reconciled version and 3 independent reviews by bilingual experts. The purpose of this methodology was to create a single universal Spanish version that would be acceptable to native Spanish speakers inside and outside of the United States. After the translation process the Spanish version was pre-tested in Argentina, Mexico, Spain and the United States. Patient responses were analyzed to identify necessary modifications. The internal consistency of the CPSI was evaluated using Cronbach's alpha. Pearson's product moment correlations were used to evaluate construct validity.

RESULTS

Data were collected from chronic prostatitis patients, including 15 in Argentina, 15 in Mexico, 4 in the United States and 3 in Spain. The translation had high reliability overall and in all subscales (Cronbach's coefficient alpha = 0.81 to 0.94), and the subscales correlated well with each other (r = 0.76 to 0.97). However, patients expressed difficulty in distinguishing the response categories "a menudo" ("often") from "normalmente" ("usually") in question 3. We revised "a menudo" to "muchas veces" ("much of the time") and "normalmente" to "casi siempre" ("almost always") to improve the distinctiveness of response categories.

CONCLUSIONS

The Spanish NIH-CPSI has high reliability as well as face and construct validity in Spanish speaking men from various countries. The Spanish NIH-CPSI permits cross-cultural comparisons of men with chronic nonbacterial prostatitis.

Rapidly progressive interstitial renal fibrosis associated with Chinese herbal medications

BACKGROUND/AIM

Nephropathy after ingestion of Chinese herbs is known as a rapidly progressive form of interstitial renal fibrosis after a slimming regimen containing aristolochic acid that was identified first in Belgium. Intake of traditional Chinese herbal medicines is very popular in Taiwan. So we looked for similar cases in our hospital.

METHODS

From 1994 to 1998, we observed 20 Taiwanese patients who underwent renal biopsy for rapidly progressive renal failure of unknown origin. The medical history of these patients gave no clue to the origin of renal impairment, except for the administration of Chinese herbs before the development of renal failure in all cases.

RESULTS

Although these patients took herbal medications from various sources for different purposes, their renal biopsy specimens showed strikingly similar histological patterns: extensive paucicellular interstitial fibrosis and tubular atrophy, but the glomeruli were apparently intact. They also had similar clinical features, such as a nearly normal blood pressure, obvious anemia, insignificant edema, low-grade proteinuria, and glucosuria. The renal function declined rapidly in most cases; 15 patients underwent dialysis within 3 months of renal biopsy, and 7 patients received emergency dialysis when they first came to our hospital. On clinical and morphological grounds, the nephropathy in our patients appears similar to Chinese herb nephropathy.

CONCLUSIONS

Because of the diversity of the herbal regimens used, in addition to aristolochic acid, other unidentified phytotoxins may also play a role in this particular disease entity. There is a strong relation between rapidly progressive interstitial renal fibrosis and the consumption of Chinese herbs.

Surfactant and corticosteroid effects on lung function in a rat model of acute lung injury

OBJECTIVES

To evaluate pulmonary responses to intratracheal administration of surfactant with and without dexamethasone in rats with paraquat-induced lung injury.

DESIGN

Prospective, randomized, controlled study.

SETTING

University research facility.

SUBJECTS

Adult male Sprague Dawley rats.

INTERVENTIONS

Rats were anesthetized and underwent a tracheostomy and arterial catheter insertion 3 days after intraperitoneal injection of paraquat (35 mg/kg). The rats were ventilated for 90 mins after sequential designation as controls or as recipients of intratracheal surfactant alone (50 or 100 mg/kg) or surfactant (50 or 100 mg/kg) plus dexamethasone (0.5 mg/kg).

MEASUREMENTS AND MAIN RESULTS

Arterial blood gases were determined at 15, 30, 60, and 90 mins. After 90 mins of ventilation, a static pressure-volume curve was performed, and inflammatory cells, total protein content, and cytokines were measured in bronchoalveolar lavage fluid. Postmortem histology was then examined. Treatment with 50 mg/kg dexamethasone/Survanta and 100 mg/kg Survanta with and without dexamethasone significantly increased oxygenation shortly after instillation when compared with the control group, with the response maintained throughout the study period. Static pressure-volume curves showed that the group receiving 100 mg/kg dexamethasone/Survanta had significantly higher lung volumes than the control group. Total cell, neutrophil, and macrophage counts were decreased significantly in the animals treated with 100 mg/kg dexamethasone/Survanta compared with untreated control rats. Total protein recovered from bronchoalveolar lavage fluid in the animals treated with 100 mg/kg Survanta with and without dexamethasone was decreased significantly compared with control animals. The histologic appearance of the lungs was markedly better in the groups treated with surfactant with or without dexamethasone.

CONCLUSIONS

Results suggest that the combined administration of high doses of intratracheal surfactant and dexamethasone improves gas exchange, ameliorates lung inflammation, and alleviates lung damage after paraquat-induced lung injury. Surfactant alone and lower doses of surfactant plus dexamethasone had a lesser effect on these measures.

Toxic effect of sulfur compounds on anaerobic biogranule

The effects of sulfide, sulfite and sulfate on degradation of volatile fatty acid (VFA) in UASB process have been studied by using serum bottle assay and septage-leachate acclimated biogranules. The relative toxicity of the compounds towards methane production and degradation of total VFA varied as SO(4)(2-) -S>S(2-)>SO(3)(2-) -S and SO(4)(2-) -S>SO(3)(2-) -S>S(2-), respectively. The difference of this order shows the importance of choosing monitoring factor in evaluating the effect of sulfur compounds on a UASB system. For the individual VFA the effects of sulfur compounds depended on the types of VFA. The VFA-degrading activity of anaerobic biogranules was decreased by 50% when 34, 26 and 20mg of S(2-), SO(3)(2-) -S and SO(4)(2-) -S were added to each gram of biomass, respectively. A comparison of the toxicity-resistance between two different anaerobic biogranules that acclimatized with septage-leachate mixture and septage was also made. In the presence of the leachate, the toxicity-resistance of biogranules was not weakened to sulfide and sulfate but was enhanced to sulfite.

Extra-articular deformity in distal radial fractures treated by external fixation

OBJECTIVE

To determine the radiographic outcome in fractures of the distal radius treated with closed reduction and external fixation.

DESIGN

A retrospective study.

SETTING

The orthopedic department of National Taiwan University Hospital.

PATIENTS

Eighty-five consecutive patients (36 female, 49 male), average age 48 years, with fractures of the distal radius seen between March 1995 and June 1998.

INTERVENTIONS

Closed reduction and external fixation of fractures, followed up by good-quality posteroanterior and lateral radiographs to evaluate healing.

MAIN OUTCOME MEASURES

Radial height, radial inclination and volar tilt were measured on radiographs obtained initially, immediately postoperatively and at the time of removal of external fixation. Data were analyzed by the t-test.

RESULTS

Immediately after reduction and fixation, there was a significant improvement in the measurements of radial height and radial inclination. This improvement was gradually lost and height and inclination were significantly decreased at the time the external fixation device was removed. External fixation did not improve the volar tilt.

CONCLUSION

External fixation is a popular method to improve the reduction of osseous deformity but cannot effectively protect comminuted distal radial fractures from loss of reduction, which may be associated with shortening and redisplacement.

Self-association of CIITA and its transactivation potential

The major histocompatibility complex (MHC) class II transactivator (CIITA) regulates the expression of genes involved in the immune response, including MHC class II genes and the interleukin-4 gene. Interactions between CIITA and sequence-specific, DNA-binding proteins are required for CIITA to function as an activator of MHC class II genes. CIITA also interacts with the coactivators CBP (also called p300), and this interaction leads to synergistic activation of MHC class II promoters. Here, we report that CIITA forms complexes with itself and that a central region, including the GTP-binding domain is sufficient for self-association. Additionally, this central region interacts with the C-terminal leucine-rich repeat as well as the N-terminal acidic domain. LXXLL motifs residing in the GTP-binding domain are essential for self-association. Finally, distinct differences exist among various CIITA mutant proteins with regard to activation function, subcellular localization, and association with wild-type protein and dominant-negative potential.

Prenatal diagnosis of cleft palate by three-dimensional ultrasound

Prenatal diagnosis of cleft palate is very important to prenatal consultation and management after birth. To examine if three-dimensional (3-D) ultrasound (US) is an accurate diagnostic method for clinical use, we analyzed our experience in detecting cleft palate by 3-D US. From June 1996 to January 2000, 21 fetuses with facial clefts were scanned by 2-D US, as well as by 3-D US. The coronal and oblique planes were reconstructed by 3-D US to detect the cleft palate. In addition, level II US was performed to find any possibly associated anomalies. All the scans were recorded on optic disks for final analysis. In our study, the gestational age when prenatal diagnosis was made by US initially was between 20 and 34 weeks. The accuracy for prenatal diagnosis of cleft lip with or without cleft palate by 3-D US was 100%, which was superior to that by 2-D US (p < 0.05). In addition, we proposed a novel method to evaluate the cleft palate systemically by 3-D US. In conclusion, from our study, fetuses with cleft lip combined with or without cleft palate can be easily differentiated by 3-D US. The reconstruction of coronal and oblique planes by 3-D US is a powerful tool for detecting cleft palate.

Genetic analysis of recent Taiwanese isolates of a variant of coxsackievirus A24

Epidemics of acute hemorrhagic conjunctivitis (AHC) caused by a variant of coxsackievirus A24 (CA24v) reappeared in Taiwan in 1990 and 1994, following the first two epidemics of 1985--86 and 1988--89. To analyze the genetic diversity of recent CA24v in Taiwan, 7 Taiwanese strains isolated during the 1990--94 period were studied together with one Japanese and two Thai strains isolated in 1993. A fragment of 674 nucleotides between the carboxy terminal 3A and the amino terminal 3D polymerase, including the entire 3C protease (3C(pro)), was amplified by a reverse transcription-polymerase chain reaction (RT-PCR) and the nucleotide sequences were determined. In the 549 nucleotides (183 amino acids) of the entire 3C(pro), we found nucleotide differences at 80 positions between 10 strains and the prototype strain, EH24/70, one of the earliest strains of CA24v. Most of the nucleotide changes were synonymous substitutions and only nine amino acid changes were found. The nucleotide sequence homologies among 71 strains worldwide were 88-100%. These 71 nucleotide sequences were then analyzed by Neighbor-joining method and phylogenetically separated into three distinct genotypes. Genotype I consisted of early strains isolated in 1970--71 from Singapore and Hong Kong. Genotype II included isolates from Singapore and Thailand obtained in 1975. Genotype III comprised strains from the eastern hemisphere isolated in 1985--94 from Japan, Taiwan, China, Hong Kong, Thailand, Singapore, Pakistan and Ghana. They were further divided chronologically into six clusters. The recent isolates from Taiwan obtained in 1985/1986, 1988/1989 and 1990--94 were classified into genotype III Clusters 1, 5, and 6 respectively. The evolutionary rate was re-estimated to be 3 x 10(- 3) 30 years after the emergence of the virus.

Fibrillary glomerulonephritis

The occurrence of fibrillary glomerulonephritis is unusual in Taiwan, whereas it occurs in approximately 1% of renal biopsy specimens taken in the United States of American. This disease is characterized by extracellular randomly arranged non-branching Congo red-negative microfibrils within glomeruli. The microfibrils are less than 30 nm in diameter, and electron microscopy is essential for diagnosis. Differential diagnosis of the deposition of extracellular non-branching microfibrils within glomeruli is important because discrete diseases have different therapeutic and prognostic implications. The report will discuss two cases of biopsy-proved fibrillary glomerulonephritis who presented with proteinuria, hematuria, renal insufficiency, and hypertension. It is noteworthy that the renal function persistently went downhill, even though the physician treated the patients with corticosteroids, pulse treatment and immunosuppressive agents.

A peritoneal mesothelioma in a captive aardwolf (Proteles cristatus)

A 10-year-old male aardwolf (Proteles cristatus) was presented abdominal distention and emaciation for 3 months. Physical examination revealed firm abdominal masses with effusions. Cytologic assessment of the effusion showed uniform round tumor cells with a surface brush border. Necropsy showed white velvety masses covering the peritoneal surface of the liver, gall bladder, stomach, omentum, mesentery, spleen, intestine, abdominal wall and diaphragm. Histologic examination demonstrated papillary projections, lined with cuboidal tumor cells supported by fibrous connective tissue cores, arising from the serosa of visceral organs. Cytoplasmic vacuolation and a surface brush border were evident on some cells under light microscopy. Tumor cells stained positive for both cytokeratin (AE1/AE3) and vimentin. Electron microscopy showed prominent surface microvilli, rough endoplasmic reticulum, mitochondria and desmosomes in tumor cells. This may be the first reported case of peritoneal mesothelioma in a captive wild aardwolf.

The uneven landscape of newborn intensive care services: variation in the neonatology workforce

CONTEXT

In the past 30 years, the number of neonatologists has increased while total births have remained nearly constant. It is not known how equitably this expanded workforce is distributed.

OBJECTIVE

To determine the geographic distribution of neonatologists in the United States.

DATA SOURCES

1996 American Medical Association physician masterfiles; 1999 survey of all U.S. neonatal intensive care units; 1995 American Hospital Association hospital survey; and 1995 U.S. vital records.

MEASURES

The number of neonatologists and neonatal mid-level providers per live birth within 246 market-based regions.

RESULTS

The neonatology workforce varied substantially across neonatal intensive care regions. The number of neonatologists per 10,000 live births ranged from 1.2 to 25.6 with an interquintile range of 3.5 to 8.5. The weakly positive correlation between neonatologists and neonatal mid-level providers per live birth is not consistent with substitution of neonatal mid-level providers for neonatologists (Spearman rank-correlation coefficient, 0.17; P < 0.01). There was no difference in the percentage of neonatal fellows in the lowest and highest workforce quintile (14% vs. 16%) or in the percentage of neonatologists engaged predominantly in research, teaching, or administration (14% in lowest and highest quintiles).

CONCLUSIONS

The regional supply of neonatologists varies dramatically and cannot be explained by the substitution of neonatal mid-level providers or by the presence of academic medical centers. Further research is warranted to understand whether neonatal intensive care resources are located in accordance with risk and whether more resources improve newborn outcomes.

Multifactorial analysis of an MOD restored human premolar using auto-mesh finite element approach

The use of an mesial-occlusal-distal (MOD) restoration in repairing a large carious lesion depends on many factors. Biomechanical performance is one of the most important. It has been recognized that resistance to restoration failure is not solely a biological concern (e.g. toxicity), but that the cavity shape, dimensions, and the state of stress must all be taken into account. In the present study, a newly developed auto-mesh program was used to generate 30 three-dimensional (3D) finite element (FE) models simulating the biomechanics for multiple factorial design of the MOD gold restoration in a maxillary second premolar. Stress levels were related to individual design factors (e.g. pulpal wall depth [P], isthmus width [W] and interaxial thickness [T]) and to their interactions under the worst physiological scenario: a concentrated bite force acting on lingual cusp with debonded interfaces between cavity walls and restorations. The results showed that enlarging the volume of the MOD cavity significantly increased stresses in enamel but did not intentionally affect stresses in dentin. The alternation of individual design parameters significantly changed the peak stresses (P < 0.05). For all three parameters, except for the width, the peak stress increased as the cavity dimension increased. Stress elevation rate (termed as 'volumetric stress rate'--stress elevation by increasing one unit volume of the restored materials) was different among three design factors. Depth was the most critical factor governing the stress elevation in enamel (1.76 MPa mm(-3)) while length (interaxial thickness) was the most important parameter in dentin (0.49 MPa mm(-3)). Width was the least compromising factor to the remaining tooth, 0.32 MPa mm(-3) for enamel and -0.23 MPa mm(-3) for dentin. The findings, at its core, did not fully agree with the traditional concept that the preservation of tooth substances will reduce risk of tooth fracture. This study leaves open possibility for the structural optimization of the MOD restoration.

Dendritic cell-specific MHC class II transactivator contains a caspase recruitment domain that confers potent transactivation activity

The MHC class II transactivator (CIITA) is a critical transcription factor that regulates genes involved in antigen presentation function. At least three functional forms of CIITA gene products are transcribed from three different promoters. The CIITA gene expressed in dendritic cells (DC-CIITA) has a unique first exon encoding an extended N-terminal region of CIITA. Here, we show that the N terminus of DC-CIITA has high homology to a caspase recruitment domain (CARD) found in components of apoptosis and nuclear factor-kappaB signaling pathways. However, DC-CIITA does not regulate cell death, nor does it induce nuclear factor-kappaB activity. Instead, DC-CIITA is transcriptionally a more potent activator of the MHC class II gene than the form expressed in B cells. A single amino acid substitution in the CARD of DC-CIITA, predicted to disrupt CARD-CARD interactions, diminished the transactivation potential of DC-CIITA. These results indicate that the CARD in the context of CIITA serves as a regulatory domain for transcriptional activity and may function to selectively enhance MHC class II gene expression in dendritic cells.

Effect of the neuroprotective agent riluzole on intracellular Ca2+ levels in IMR32 neuroblastoma cells

Riluzole is an effective neuroprotective drug. Its effect on intracellular free Ca2+ levels ([Ca2+]i) has not been explored. This study examined the effect of riluzole on [Ca2+]i in IMR32 neuroblastoma cells using fura-2 as a Ca2+ probe. Riluzole 0.1-1 mM increased [Ca2+]i in a concentration-dependent manner. Removal of extracellular Ca2+ inhibited the response by 52 +/- 5%. The [Ca2+]i increase induced by 0.2 mM riluzole was unaltered by 0.1 mM La3+ or 10 microM verapamil, but was inhibited by 51 +/- 4% by 10 microM nifedipine. In Ca2+-free medium, pretreatment with 1 microM thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor) reduced the 0.2 mM riluzole-induced Ca2+ release by 44 +/- 3%; this reduction was augmented to 66 +/- 5% by additionally depleting the Ca2+ stores in the Golgi complex with 50 microM brefeldin A. Inhibition of inositol 1,4,5-trisphosphate formation by 2 microM U73122, a phospholipase C inhibitor, did not affect Ca2+ release induced by 0.2 microM riluzole. It was concluded that the neuroprotective agent riluzole increased [Ca2+]i in IMR32 neuroblastoma cells concentration-dependently by releasing Ca2+ from multiple stores in an inositol 1,4,5-trisphosphate-independent manner and also by inducing nifedipine-sensitive Ca2+ influx.

Numerical investigation of the factors affecting interfacial stresses in an MOD restored tooth by auto-meshed finite element method

Many researches have addressed the high correlation between the fracture of restored teeth and the prepared cavity geometry. In addition, concerns about bonding versus debonding dental materials from cavity walls and different occlusal force conditions could also alter the mechanical responses in a restored tooth. This study employed an automatic mesh procedure to investigate the mechanical interactions between different interfacial conditions and cavity parameters such as pulpal wall depth under different chewing functions. The results indicated that when occlusal force was applied directly on the tooth, it could increase unfavourable stress dramatically. When interfacial fixation was simulated as the contact condition between the tooth tissue and restorative material, it might increase the fracture potential exponentially compared with the bonded interface. For pulpal wall depth analyses, greater risks of fracture for the remaining tooth were observed in deeper cavity of mesio-occlusal-distal (MOD) restorations and the existence of a pulpal wall is essential even it is only 1 mm above the gingival wall.