Four-year Prostate-specific Antigen Response Rate as a Predictive Measure in Intermediate-risk Prostate Cancer Treated With Ablative Therapies: The SPRAT Analysis

AIMS

There is a lack of early predictive measures of outcome for patients with intermediate-risk prostate cancer (PCa) treated with stereotactic body radiotherapy (SBRT). The aim of the present study was to explore 4-year prostate-specific antigen response rate (4yPSARR) as an early predictive measure.

MATERIALS AND METHODS

Individual patient data from six institutions for patients with intermediate-risk PCa treated with SBRT between 2006 and 2016 with a 4-year (42-54 months) PSA available were analysed. Cumulative incidences of biochemical failure and metastasis were calculated using Nelson-Aalen estimates and overall survival was calculated using the Kaplan-Meier method. Biochemical failure-free survival was analysed according to 4yPSARR, with groups dichotomised based on PSA <0.4 ng/ml or ≥0.4 ng/ml and compared using the Log-rank test. A multivariable competing risk analysis was carried out to predict for biochemical failure and the development of metastases.

RESULTS

Six hundred and thirty-seven patients were included, including 424 (67%) with favourable and 213 (33%) with unfavourable intermediate-risk disease. The median follow-up was 6.2 years (interquartile range 4.9-7.9). The cumulative incidence of biochemical failure and metastasis was 7 and 0.6%, respectively; overall survival at 6 years was 97%. The cumulative incidence of biochemical failure at 6 years if 4yPSARR <0.4 ng/ml was 1.7% compared with 27% if 4yPSARR ≥0.4 ng/ml (P < 0.0001). On multivariable competing risk analysis, 4yPSARR was a statistically significant predictor of biochemical failure-free survival (subdistribution hazard ratio 15.3, 95% confidence interval 7.5-31.3, P < 0.001) and metastasis-free survival (subdistribution hazard ratio 31.2, 95% confidence interval 3.1-311.6, P = 0.003).

CONCLUSION

4yPSARR is an encouraging early predictor of outcome in patients with intermediate-risk PCa treated with SBRT. Validation in prospective trials is warranted.

A miniaturized, tethered, spectrally-encoded confocal endomicroscopy capsule

BACKGROUND AND OBJECTIVE

The tethered spectrally-encoded confocal endomicroscopy (SECM) capsule is an imaging device that once swallowed by an unsedated patient can visualize cellular morphologic changes associated with gastrointestinal (GI) tract diseases in vivo. Recently, we demonstrated a tethered SECM capsule for counting esophageal eosinophils in patients with eosinophilic esophagitis (EoE) in vivo. Yet, the current tethered SECM capsule is far too long to be widely utilized for imaging pediatric patients, who constitute a major portion of the EoE patient population. In this paper, we present a new tethered SECM capsule that is 33% shorter, has an easier and repeatable fabrication process, and produces images with reduced speckle noise.

MATERIALS AND METHODS

The smaller SECM capsule utilized a miniature condenser to increase the fiber numerical aperture and reduce the capsule length. A custom 3D-printed holder was developed to enable easy and repeatable device fabrication. A dual-clad fiber (DCF) was used to reduce speckle noise.

RESULTS

The fabricated SECM capsule (length = 20 mm; diameter = 7 mm) had a similar size and shape to a pediatric dietary supplement pill. The new capsule achieved optical sectioning thickness of 13.2 μm with a small performance variation between devices of 1.7 μm. Confocal images of human esophagus obtained in vivo showed the capability of this new device to clearly resolve microstructural epithelial details with reduced speckle noise.

CONCLUSIONS

We expect that the smaller size and better image performance of this new SECM capsule will greatly facilitate the clinical adoption of this technology in pediatric patients and will enable more accurate assessment of EoE-suspected tissues. Lasers Surg. Med. 51:452-458, 2019. © 2019 Wiley Periodicals, Inc.

Clinical Translation of Tethered Confocal Microscopy Capsule for Unsedated Diagnosis of Eosinophilic Esophagitis

Esophagogastroduodenoscopy (EGD) is a widely used procedure, posing significant financial burden on both healthcare systems and patients. Moreover, EGD is time consuming, sometimes difficult to tolerate, and suffers from an imperfect diagnostic yield as the limited number of collected biopsies does not represent the whole organ. In this paper, we report on technological and clinical feasibility of a swallowable tethered endomicroscopy capsule, which is administered without sedation, to image large regions of esophageal and gastric mucosa at the cellular level. To demonstrate imaging capabilities, we conducted a human pilot study (n = 17) on Eosinophilic Esophagitis (EoE) patients and healthy volunteers from which representative cases are presented and discussed. Results indicate that, compared to endoscopic biopsy, unsedated tethered capsule endomicroscopy obtains orders of magnitude more cellular information while successfully resolving characteristic tissue microscopic features such as stratified squamous epithelium, lamina propria papillae, intraepithelial eosinophils, and gastric cardia and body/fundic mucosa epithelia. Based on the major import of whole organ, cellular-level microscopy to obviate sampling error and the clear cost and convenience advantages of unsedated procedure, we believe that this tool has the potential to become a simpler and more effective device for diagnosing and monitoring the therapeutic response of EoE and other esophageal diseases.

Features of children with positive celiac serology and type 1 diabetes mellitus

Prior studies have reported disparate clinical presentations between children with celiac disease and type 1 diabetes mellitus and those with celiac disease alone. Studies focusing on differences in endoscopic and histopathological findings, however, are limited. We reviewed children aged 2-18 years, presenting for an initial evaluation between January 2000 and December 2010. Data on medical history, serologic markers, upper endoscopy, and histopathology were collected. Only the children with positive celiac serology who had upper endoscopy performed within 3 months of the initial visit were included. We identified 294 children who fulfilled the criteria, 21 of whom had diagnosed type 1 diabetes mellitus. Diabetic children were more likely to have absence of gastrointestinal symptoms. Erythematous duodenal and esophageal mucosa on endoscopy, and histopathology suggestive of reflux esophagitis were more common in the diabetes group. Diabetic children with positive celiac serology had different histopathological features as compared with their non-diabetic counterparts.

Predictors of dietary gluten avoidance in adults without a prior diagnosis of celiac disease

OBJECTIVE

Prior studies have shown that dietary gluten avoidance (DGA) is relatively common in children without previously diagnosed celiac disease (CD), and several clinical predictors of DGA have been found. However, available data on predictors of DGA in adults without diagnosed CD are limited. The aim of this study was to determine the independent predictors of DGA in this population.

METHODS

We performed a structured medical record review of 376 patients, ages ≥ 20 y, who had never been formally diagnosed with CD, presenting for an initial CD evaluation (ICD-9-CM 579.0) between January 2000 and December 2010 at two large Boston teaching hospitals. We collected data including demographic characteristics, medical history, history of CD serology before referral, and self-reported DGA. Predictors of DGA were determined using multivariable logistic regression.

RESULTS

Mean age was 47 (SD = 17) years. We found that 41 patients (10.9%; 95% confidence interval [CI], 7.9-14.5) had avoided gluten at some time in their lives. Most patients had subjective abdominal complaints or bowel movement changes. History of CD seropositivity before referral was noted in 14%. Independent predictors of DGA (P < 0.05) were lactose intolerance (odds ratio [OR], 2.8; 95% CI, 1.1-7.5), food allergy (OR, 3.8; 95% CI, 1.04-13.7), and history of positive serology of less-specific CD markers before the referral (OR, 3.2; 95% CI, 1.3-7.9).

CONCLUSIONS

Gluten avoidance is common in a clinic population of adults without prior CD diagnosis. The recognized predictors suggest that DGA may associate with conditions presenting with nonspecific gastrointestinal complaints and perhaps with the perceived benefits of DGA among patients with prior history of positive CD serology.

Multicenter study on season of birth and celiac disease: evidence for a new theoretical model of pathogenesis

OBJECTIVE

To investigate whether season of birth is associated with celiac disease (CD).

STUDY DESIGN

We performed a medical record review of 1964 patients with biopsy-proven CD at 3 teaching hospitals (2 pediatric centers and 1 adult center) between 2000 and 2010. The first positive small intestinal biopsy result defined age of diagnosis. The observed proportions of births in each season (spring [March-May], summer [June-August], fall [September-November], and winter [December-February]) were compared with the expected proportions using binomial probability tests.

RESULTS

The mean age at diagnosis was 9.8 ± 5.0 years in the 2 pediatric centers and 43.6 ± 15.8 years in the adult center. The cohort was predominately female (69%). Overall, more patients were born in spring (27%) than in any other season: summer (25%), fall (25%), and winter (23%). In patients diagnosed before age 15 years, the spring birth excess was present in boys (33%; P = .0005), but not in girls (26%; P = .43). The sex difference in season of birth was less striking in patients with CD diagnosed at age ≥15 years.

CONCLUSION

Season of birth is an environmental risk factor for CD, particularly in boys diagnosed before age 15 years. The results are consistent with a new theoretical model that integrates potential environmental factors (eg, gluten introduction, ultraviolet-B exposure, vitamin D status) and acute viral gastrointestinal infections in early childhood.

Predictors of gluten avoidance and implementation of a gluten-free diet in children and adolescents without confirmed celiac disease

OBJECTIVES

To determine independent predictors of gluten avoidance and of a physician's decision to initiate a gluten-free diet (GFD) in children and adolescents without confirmed celiac disease.

STUDY DESIGN

We performed a structured medical record review of 579 patients aged 1-19 years presenting for evaluation of celiac disease between January 2000 and December 2010 at a large Boston teaching hospital. We collected data including demographic information, medical history, serology, small intestinal biopsy, history of gluten avoidance, and the postworkup recommendation of implementation of a GFD. Predictors of gluten-related issues were identified by multivariate logistic regression.

RESULTS

Among 579 children without a previous diagnosis of celiac disease (mean age, 8.7 years), 43 (7.4%) had ever avoided gluten. Independent predictors of gluten avoidance were irritability or poor temper (OR, 3.2), diarrhea (OR, 2.5), weight issues (OR, 0.4), pervasive developmental disorder (OR, 5.3), and family history of celiac disease (OR, 2.2). Among 143 children without confirmed celiac disease who underwent diagnostic evaluation, several predictive factors were associated with a physician- recommended/parent-initiated GFD: irritability (OR, 6.4), diarrhea (OR, 3.4), pervasive developmental disorder (OR, 7.9), and positive serology before the referral (OR, 4.3).

CONCLUSION

Gluten avoidance among children and adolescents without a previous diagnosis of celiac disease is relatively common. The identified predictors suggest that gluten avoidance is associated with nonspecific behavioral and gastrointestinal complaints and perhaps with the perceived dietary responses in another family member thought to have celiac disease.

Predictors of duodenal bulb biopsy performance in the evaluation of coeliac disease in children

AIMS

Studies on the role of duodenal bulb biopsy (DBB) in coeliac disease (CD) evaluation have increased in recent years; growing evidence suggests that the disease can present solely in the duodenal bulb. Moreover, recent CD guidelines recommend obtaining a DBB. The study aim was to examine DBB performance in children undergoing CD evaluation and to identify independent predictors of DBB performance.

METHODS

The authors performed a structured chart review of children aged <18 years who underwent CD evaluation between 2000 and 2010 at a large teaching hospital. The authors collected data including demographics, serology, endoscopy and histopathological findings. Predictors of DBB performance (obtained vs not obtained) were determined using multivariable logistic regression.

RESULTS

Among 616 children who underwent endoscopy, DBB was performed in 103 children (17%, 95% CI 14% to 20%) with an increasing trend in the more recent years (2008-2010, 25%; 2004-2007, 16%; and 2000-2003, 5%, p<0.001). Three independent predictors of DBB performance were older age at endoscopy (OR 1.05 per year of age), gross gastric antral abnormalities (OR 2.81) and gross duodenal abnormalities (OR 5.55). Regarding the DBB histological findings, patchiness of CD was found in 15%. Positive Marsh III biopsy presented solely on the DBB in 6/103 (6%, 95% CI 2% to 12%) children.

CONCLUSIONS

The authors found a significant increase in DBB performance over time, but the overall performance remains suboptimal. Improving education on obtaining a DBB for CD evaluation is crucial, especially among those children in whom DBB is more likely to be omitted.

Human adipose stem cells maintain proliferative, synthetic and multipotential properties when suspension cultured as self-assembling spheroids

Adipose-derived stromal/stem cells (ASCs) have been gaining recognition as an extremely versatile cell source for tissue engineering. The usefulness of ASCs in biofabrication is further enhanced by our demonstration of the unique properties of these cells when they are cultured as three-dimensional cellular aggregates or spheroids. As described herein, three-dimensional formulations, or self-assembling ASC spheroids develop their own extracellular matrix that serves to increase the robustness of the cells to mechanical stresses. The composition of the extracellular matrix can be altered based on the external environment of the spheroids and these constructs can be grown in a reproducible manner and to a consistent size. The spheroid formulation helps preserve the viability and developmental plasticity of ASCs even under defined, serum-free media conditions. For the first time, we show that multiple generations of adherent ASCs produced from these spheroids retain their ability to differentiate into multiple cell/tissue types. These demonstrated properties support the idea that culture-expanded ASCs are an excellent candidate cellular material for 'organ printing'-the approach of developing complex tissue structures from a standardized cell 'ink' or cell formulation.

Age-related patterns in clinical presentations and gluten-related issues among children and adolescents with celiac disease

OBJECTIVES

Celiac disease (CD) is common and often cited as an "iceberg" phenomenon (i.e., an assumed large number of undiagnosed cases). Recently, atypical or asymptomatic manifestations are becoming more commonly described in older children and adolescents. Moreover, CD diagnosis in children can be complicated by several factors, including its diverse clinical presentations, delay in recognizing CD signs and symptoms, and premature dietary gluten avoidance before the formal diagnosis of CD. To date, few studies have directly examined age-related differences in clinical characteristics and gluten-related issues among children with CD. The aim of this study was to determine age-related patterns in clinical characteristics and gluten-related issues among children with confirmed CD.

METHODS

We performed a structured medical record review of biopsy-proven CD patients, aged 0-19 years, between 2000 and 2010 at a large Boston teaching hospital. Data collection included demographics, medical history, gluten-related issues, and diagnostic investigations (CD-specific serology, upper gastrointestinal endoscopy, and small intestinal biopsy). The first positive duodenal biopsy with Marsh III classification defined age of diagnosis. Patients were divided into three age groups for comparisons of the aforementioned characteristics: infant-preschool group (0-5 years), school-aged group (6-11 years), and adolescence group (12-19 years).

RESULTS

Among 411 children with biopsy-proven CD, the mean age was 9.5 (s.d. 5.1) years. Most were female (63%) and white (96%). All children had positive CD-specific serology. Most children presented with either abdominal complaints or bowel movement changes. Overall, boys were more common among infant-preschool group compared with the other age groups. More distinct clinical manifestations (vomiting, bowel movement changes, and weight issues) were apparent in the youngest group, whereas school-aged children had more subjective abdominal complaints at the initial presentation. Conversely, the adolescents were most likely to present without any gastrointestinal (GI) symptoms, but not when this was combined with absence of weight issues. Age of diagnosis was not associated with atypical extraintestinal CD presentations. Regarding the gluten-related issues, 10% of school-aged children avoided dietary gluten before the formal CD diagnosis, and 27% of the adolescents reported dietary gluten transgression within the first 12 months of diagnosis, significantly higher than the other age groups. Age differences in histopathology were also found. Whereas the infant-preschool group had a higher proportion of total villous atrophy, the older children were more likely to have gross duodenal abnormalities and chronic duodenitis suggestive of CD at the time of diagnosis.

CONCLUSIONS

Children and adolescents with CD have age-related patterns in both the clinical presentations and gluten-related issues. More pronounced clinical and histological features were determined in younger children, whereas older children more commonly presented with solely subjective abdominal complaints or even without any GI symptoms. However, silent and atypical extraintestinal CD presentations were comparable between age groups. In addition to the aforementioned presentations, the higher rates of dietary gluten avoidance and transgression in older children make CD diagnosis and management particularly challenging. These age-related patterns may further increase awareness, facilitate early diagnosis, and improve patient care of pediatric CD.

Reflectance confocal microscopy for the diagnosis of eosinophilic esophagitis: a pilot study conducted on biopsy specimens

BACKGROUND

Diagnosis of eosinophilic esophagitis (EoE) currently requires endoscopic biopsy and histopathologic analysis of the biopsy specimens to count intraepithelial eosinophils. Reflectance confocal microscopy (RCM) is an endomicroscopy technology that is capable of obtaining high-resolution, optically sectioned images of esophageal mucosa without the administration of exogenous contrast.

OBJECTIVE

In this study, we investigated the capability of a high-speed form of RCM, termed spectrally encoded confocal microscopy (SECM), to count intraepithelial esophageal eosinophils and characterize other microscopic findings of EoE.

DESIGN

A total of 43 biopsy samples from 35 pediatric patients and 8 biopsy samples from 8 adult patients undergoing EGD for EoE were imaged by SECM immediately after their removal and then processed for routine histopathology. Two SECM readers, trained on adult cases, prospectively counted intraepithelial eosinophils and detected the presence of abscess, degranulation, and basal cell hyperplasia on SECM images from the pediatric patients. A pathologist blinded to the SECM data analyzed the same from corresponding slides.

SETTING

The Gastrointestinal Unit, Massachusetts General Hospital.

RESULTS

Eosinophils by SECM demonstrated a higher reflectance than the surrounding cells and other inflammatory cells. There was good correlation between SECM and histology maximum eosinophil counts/high-power field (R = 0.76, P < .0001). Intra- and interobserver correlations for SECM counts were very good (R = 0.93 and R = 0.92, respectively; P < .0001). For the commonly used eosinophil count cutoff of 15 per high-power field, the sensitivity and specificity of SECM for EoE were 100%. The sensitivity and specificity for abscess, degranulation, and basal cell hyperplasia were 100% and 82%, 91% and 60%, and 94% and 80%, respectively. Intra- and interobserver agreements for these microscopic features of EoE were very good (κ = 0.9/0.9, 0.84/1.0, 0.91/0.81, respectively).

LIMITATION

Ex vivo study.

CONCLUSIONS

This study demonstrates that RCM can be used to accurately count intraepithelial eosinophils and identify other microscopic abnormalities associated with EoE on freshly excised biopsy samples. These findings suggest that RCM may be developed into a tool for assessing eosinophilic infiltration in the esophagus in vivo.

Heterotopic gastric mucosa causing significant esophageal stricture in a 14-year-old child

Esophageal heterotopic gastric mucosa (HGM) is not uncommon and can be seen in up to 10% of the general population among numerous reports and epidemiologic studies which have been essentially performed in adult population. Pediatric data are still limited. Diagnosis requires clinician awareness of symptomatic cases who present with dysphagia or swallowing difficulties, and thorough endoscopic examination is crucial. Early detection of cases provides favorable clinical outcome and may prevent potential significant or serious long-term consequences such as esophageal stricture or web, Barrett's esophagus or malignant transformation in pediatric population. We reported a 14-year-old male who presented with 1-year history of gradually worsening dysphagia and was found to have two salmon-colored patches, which resemble gastric mucosa, in the proximal esophagus causing significant esophageal stricture. Gastric cardiac-type mucosa with acute and chronic inflammation was documented on biopsy. After several sessions of balloon dilation and endoscopic treatment, the HGM and esophageal stricture resolved and he became asymptomatic.

Short- and long-term response to and weaning from infliximab therapy in pediatric ulcerative colitis

OBJECTIVES

We evaluated the response to infliximab in pediatric patients with ulcerative colitis (UC) and their long-term follow-up. We expanded our previous study of 14 patients and furthermore evaluated the success of weaning patients from infliximab.

PATIENTS AND METHODS

We reviewed the charts of 27 pediatric patients with UC who were treated with infliximab instead of undergoing a colectomy. Patients with new-onset UC refractory to intravenous steroids for 5 to 10 days and patients with non-steroid-dependent UC with an acute exacerbation were classified as acutely ill (n = 16); patients with chronic steroid-dependent UC were classified as chronically ill (n = 11). The Lichtiger Colitis Activity Index (LCAI) was measured for all patients at baseline and at 1 and 2 months after treatment with infliximab was initiated. Patients were regarded as successfully treated if they remained off steroids and avoided colectomy.

RESULTS

The acutely ill group had a mean LCAI score of 11.4 at induction and 0.3 after 2 months. The chronically ill group had a mean LCAI score of 11.2 at induction and 5.5 after 2 months. Treatment with infliximab was successful in 75% of acutely ill patients and in 27% of chronically ill patients. Infliximab was discontinued in 80% of successfully treated patients (83% of acutely ill, 67% of chronically ill). These patients had an average of 10 infusions and a mean follow-up time of 10 months from their last infliximab infusion.

CONCLUSIONS

Our results suggest that infliximab is more effective in acutely ill UC patients than in patients with chronic steroid-dependent UC. In addition, some patients treated with infliximab can be weaned from infliximab and maintain remission.

Genetic and cellular mechanisms in chromium and nickel carcinogenesis considering epidemiologic findings

Genetic and environmental interactions determine cancer risks but some cancer incidence is primarily a result of inherited genetic deficits alone. Most cancers have an occupational, viral, nutritional, behavioral or iatrogenic etiology. Cancer can sometimes be controlled through broad public health interventions including industrial hygiene and engineering controls. Chromium and nickel are two human carcinogens associated with industrial exposures where public health measures apparently work. Carcinogenic mechanisms of these metals are examined by electron-spin-resonance-spectroscopy and somatic-mutation-and-recombination in Drosophila melanogaster in this report. Both metals primarily affect initiation processes in cancer development suggesting important theoretical approaches to prevention and followup.

Infliximab is effective in acute but not chronic childhood ulcerative colitis

PURPOSE

The authors report their experience with infliximab in pediatric patients with ulcerative colitis (UC).

METHODS

Fourteen patients were reviewed. Group 1 included five patients with newly diagnosed, fulminant colitis refractory to 7 to 10 days of intravenous steroids. Group 2 included four patients with ulcerative colitis in remission off steroid therapy who experienced relapse and were hospitalized with fulminant colitis refractory to intravenous steroids for 7 to 10 days. Group 3 included five patients chronically dependent on steroids with colitis refractory to medical management. All patients were treated on an open-label basis with infliximab infusions of 5 mg/kg/dose at 0, 2, and 6 weeks and every 6 to 8 weeks thereafter. Follow-up was maintained for at least 6 weeks. Clinical status was scored with the Lichtiger Colitis Activity Index (LCAI) at each visit. LCAI >or=10 was considered treatment failure. We defined success as LCAI <or=2, a score consistent with UC remission. Response was categorized for each group.

RESULTS

All patients began the study with LCAI >or=11 before infliximab treatment. All group 1 patients experienced response to infliximab. All but one (75%) patient in group 2 had a response. Only one (20%) group 3 patient had a response to infliximab.

CONCLUSION

Infliximab was an effective agent in the treatment of acute UC in our patients. Long-term steroid use and emergency colectomy were avoided. Infliximab was less effective in patients who were dependent on steroids.

Infliximab therapy in pediatric Crohn's pouchitis

OBJECTIVE

We describe the prolonged clinical benefit of murine chimeric antitumor necrosis factor (TNF)-alpha monoclonal antibody, infliximab, on pediatric patients with Crohn's disease and ileal pouch anal anastomosis (IPAA).

METHODS

A retrospective review of patients originally diagnosed with ulcerative colitis, status post colectomy and IPAA, who developed findings compatible with Crohn's disease was undertaken. Refractory pouchitis developed in all patients as well as protracted symptoms of diarrhea, abdominal pain, joint pain, and incontinence. All patients received infliximab.

RESULTS

Four pediatric patients (2 males and 2 females) with mean age of 14.5 years (range 11-18 years) were studied. The development of perianal fistulas in 2 patients, granuloma on biopsy in 1 patient and perianal skin tag in 1 patient, led to a diagnosis change of CD. After failure to respond to antibiotics, aminosalicylates and immunomodulators such as azathioprine and 6-mercaptopurine (6-MP), all patients were treated with infliximab. Patients received infliximab infusions at a dose of 5 mg/kg, initially at weeks 0, 2 and 6 and subsequently at 8 weeks intervals in combination with an immunomodulator drug. All patients showed marked improvement clinically, endoscopically, and histologically.

CONCLUSION

Infliximab can be used successfully for the treatment of pediatric patients with Crohn's disease and IPAA who are refractory to conventional therapies.

Mesenchymal stem cells from rat visceral fat exhibit multipotential differentiation in vitro

Human subcutaneous fat-derived stem cells were recently shown to have the potential to differentiate in vitro into a variety of cell types, including adipocytes, osteoblasts, chondrocytes, and myoblasts (Zuk et al., Tissue Eng. 2001;7:211-228). Subcutaneous adipose tissue may therefore prove to be an easily acquired and abundant source of stem cells. Presently it is unclear whether mammals such as rats (which possess small or nonexistent subcutaneous fat pads) contain mesenchymal stem cells within the visceral fat of the abdominal cavity, or whether the visceral fat of any species contains stem cells. In this study we isolated and expanded a pool of mesenchymal cells from visceral fat of adult Sprague-Dawley rats and induced their differentiation in vitro into adipocytes, osteoblasts, neural cells, and chondrocytes. The differentiated phenotypes were verified by morphology as well as detection and expression of tissue-specific protein and mRNA. We conclude that despite well-documented differences in the metabolic and biochemical properties among anatomically distinct depots of fat, the visceral fat of rats contains adult mesenchymal stem cells with developmental potential similar to those isolated from subcutaneous fat in humans. Therefore, animals such as rats provide both a source of fat-derived stem cells and an immunocompetent, autologous host animal in which to investigate the capacity of the fat-derived cells to differentiate and form tissues in vivo.

Combining Drosophila melanogaster somatic-mutation-recombination and electron-spin-resonance-spectroscopy data to interpret epidemiologic observations on chromium carcinogenicity

Lung cancers are significantly increased among workers exposed to chromate (Cr6+, Cr3+), chromium pigments (Cr6+) and chromium plating (Cr6+). Chromium lung burdens and cancer risk increase proportionately with duration of employment at long latencies. However, this epidemiologic information alone is insufficient in determining whether Cr6+ or Cr3+ are equally important in causing cancer. We have attempted to combine epidemiologic data with data from the Drosophila melanogaster somatic-mutation-recombination-test and from the in vitro electron-spin-resonance spectroscopy study to demonstrate that following somatic recombination plays a more important role than somatic mutation in chromium carcinogenesis. Cr4+ is more important than Cr5+ or Cr6+ in inducing somatic recombination while Cr6+ produces more and bigger clones than Cr4+ in somatic mutation. Cr3+ produces negative results in this fruit-fly wing-spot-assay. When the larvae and flies exposed to Cr6+ and Cr4+ are examined by ESR, only Cr5+ and Cr3+ are found. Thermodynamic parameters deltaE, deltaH, and deltaS are also estimated from these latter experiments to explain the relative importance of Cr6+, Cr4+, Cr3+ in chromium carcinogenesis among exposed industrial workers.

Multilineage cells from human adipose tissue: implications for cell-based therapies

Future cell-based therapies such as tissue engineering will benefit from a source of autologous pluripotent stem cells. For mesodermal tissue engineering, one such source of cells is the bone marrow stroma. The bone marrow compartment contains several cell populations, including mesenchymal stem cells (MSCs) that are capable of differentiating into adipogenic, osteogenic, chondrogenic, and myogenic cells. However, autologous bone marrow procurement has potential limitations. An alternate source of autologous adult stem cells that is obtainable in large quantities, under local anesthesia, with minimal discomfort would be advantageous. In this study, we determined if a population of stem cells could be isolated from human adipose tissue. Human adipose tissue, obtained by suction-assisted lipectomy (i.e., liposuction), was processed to obtain a fibroblast-like population of cells or a processed lipoaspirate (PLA). These PLA cells can be maintained in vitro for extended periods with stable population doubling and low levels of senescence. Immunofluorescence and flow cytometry show that the majority of PLA cells are of mesodermal or mesenchymal origin with low levels of contaminating pericytes, endothelial cells, and smooth muscle cells. Finally, PLA cells differentiate in vitro into adipogenic, chondrogenic, myogenic, and osteogenic cells in the presence of lineage-specific induction factors. In conclusion, the data support the hypothesis that a human lipoaspirate contains multipotent cells and may represent an alternative stem cell source to bone marrow-derived MSCs.

A novel device for the simple and efficient refinement of liposuctioned tissue

In short, our device allows a surgeon who is harvesting adipose tissue for autologous fat transplantation to immediately, easily, efficiently, and sterilely isolate adipose tissue from the unwanted waste components that are associated with primary liposuction effluent. It does so by "trapping" the fat tissue contained within raw liposuction effluent. Once the tissue fraction has been separated, the device design then allows for direct implantation or subsequent washing/rinsing of the tissue with saline/buffer of choice in preparation for tissue reimplantation.

Prospective analysis suggests susceptibility genes for deficiencies of IgA and several other immunoglobulins on the [HLA-B8, SC01, DR3] conserved extended haplotype

The extended major histocompatibility complex (MHC) haplotype [HLA-B8, SC01, DR3] is increased in frequency among patients with immunoglobulin (Ig)A deficiency and common variable immunodeficiency. Because the genomic region from HLA-B to HLA-DR/DQ is virtually the same on all instances of the haplotype in the general population, we reasoned that all independent instances of [HLA-B8, SC01, DR3] carry MHC susceptibility genes for these disorders. To define immunoglobulin deficiencies determined by genes on this haplotype and their mode of expression and penetrance, serum immunoglobulin class and IgG subclass concentrations were determined prospectively in homozygotes and heterozygotes of this haplotype and in Caucasian controls. Prevalence of individual immunoglobulin deficiencies in persons with [HLA-B8, SC01, DR3] ranged from 13% to 37%, significantly higher than rates in non-carriers or general controls. We found significantly increased frequencies of IgA and IgG4 deficiency only in homozygotes (13.3% and 30%, respectively) compared with heterozygotes (1.7% and 3.4%) or non-carriers (1.6% each), suggesting recessive expression. In contrast, IgD and IgG3 deficiencies were significantly more common in both homozygotes (36.7% and 30%) and heterozygotes (20.3% and 17.5%) compared with controls (4.9% and 3.4%), suggesting dominant inheritance. These results indicate multiple distinct susceptibility genes, some recessive and others dominant, for deficiency of IgA, IgD, IgG3 or IgG4 (but not for IgE, IgG1, IgG2 or IgM) on [HLA-B8, SC01, DR3]. These observations may also help to explain the observed associations of [HLA-B8, SC01, DR3] with both IgA deficiency and common variable immunodeficiency and the common occurrence of IgG subclass deficiencies in some patients with IgA deficiency.

Modulation by temperature of the genotoxic potency of cisplatin in Drosophila wing spot assay

Effects of temperature on genotoxic potency of cisplatin were studied in the Drosophila wing spot assay. A fixed concentration of 0.05 mM cisplatin was evaluated for genotoxicity at 4 temperatures (18, 20, 25, and 29 degrees C). The compound was found to be a positive inducer of all three endpoints at all temperatures when compared to the water controls. While no effect of temperature was found on the percentages of cisplatin-treated wings with small spots, there were significant effects for large spots and twin spots. The capacity of cisplatin to induce both large spots and twin spots tended to increase with rising temperature. A significant linear regression was obtained in regard to temperature and number of cisplatin-induced large spots per wing. The lack of any effect of temperature on induced small spots provides additional evidence that small spots may be qualitatively different from large spots and twin spots. The observed enhancement by higher temperature of cisplatin's genotoxic potency is likely due in part to increased cellular uptake of the mutagen. Wide temperature fluctuations should be avoided when conducting the wing assay. Although the customary temperature for performing the assay has been within the range 24-25 degrees C, the optimum temperature for maximizing genotoxic potency (and sensitivity of the assay) may be nearer 27 degrees C.

Emerging approaches to the tissue engineering of fat

The eventual development of tissue-engineered fat equivalents for reconstructive and augmentation purposes will be most welcome by nearly every surgical discipline and prove to be especially useful for plastic surgeons. The clinical applications for which tissue-engineered fat will be particularly useful are vast and varied and can be loosely categorized into reconstructive, cosmetic, corrective, and orthotic indications. In this article, the authors discuss the emerging tissue-engineering strategies for fat, including the procurement of autologous cells, cell growth and differentiation, implantation and engraftment, polymer scaffolds, and implant integration and histogenesis.

Inhibition of peripheral blood mononuclear cell proliferation by cardiac glycosides

INTRODUCTION

Prior studies have shown that ouabain, a cardiac glycoside that inhibits the sodium, potassium adenosine triphosphatase (Na+,K+ ATPase) enzyme, downregulates phytohemagglutinin (PHA)-induced peripheral blood mononuclear cell (PBMNC) proliferation.

OBJECTIVE

This study examined and compared the effects of both ouabain and digoxin, a cardiac glycoside used therapeutically in humans, on PBMNC proliferation.

METHODS

Peripheral blood mononuclear cells were isolated from healthy human subjects, incubated for 72 hours with and without PHA (2%) in the presence and absence of ouabain (10(-12) M to 10(-4) M) or digoxin (10(-9) M to 10(-6) M), and pulsed with 3H thymidine.

RESULTS

For PHA-stimulated PBMNCs in the ouabain-treated group (n = 10 subjects), the mean (+/-STD) % uptake (% 3H thymidine uptake in absence of ouabain) was 80.5 +/- 6.0 at 10(-12) M ouabain, 73.1 +/- 8.4 at 10(-10) M, 47.89 +/- 13.1 at 10(-8) M, 6.9 +/- 3.2 at 10(-6) M, and 3.4 +/- 1.6 at 10(-4) M. For PHA-stimulated cells in the digoxin-treated group (n = 9 subjects), the mean (+/-STD) % uptake (% 3H thymidine uptake in absence of digoxin) was 89.8 +/- 9.8 at 10(-9) M digoxin, 92.6 +/- 8.2 at 10(-8) M, 54.3 +/- 19.8 at 10(-7) M, and 1.0 +/- 2.4 at 10(-6) M. Repeated measures ANOVA demonstrated a significant effect of concentration of both glycosides on PBMNC proliferation (P < .01). The inhibitory effect was reversible, but was largely abbrogated if ouabain was added after 48 hours of incubation with PHA. Further, the inhibitory effect extended to PBMNCs stimulated with recall antigen (tetanus) and to fractionated PBMNCs (CD4+, CD8+ and CD19+) stimulated with mitogens. Additionally, dose-response inhibitory effects of glycosides on PBMNC Na+,K+ ATPase enzyme activity and interleukin-2 (IL-2) secretion by PHA-stimulated PBMNC were also noted. Neither glycoside had an effect on spontaneous PBMNC proliferation (no PHA) or trypan blue exclusion.

CONCLUSIONS

These studies demonstrate that both cardiac glycosides inhibited PHA-induced PBMNC proliferation, possibly via Na+,K+ ATPase inhibition, but not via cell toxicity. The concentration range over which inhibition was observed was similar for both glycosides. The results raise the possibility that therapeutic or toxic doses of digoxin could have an effect on cell-mediated immunity in vivo.

Comparison of bacteria growth in single and pooled platelet concentrates after deliberate inoculation and storage

BACKGROUND

The ability to store pools of platelet concentrates (PCs) for extended periods would provide logistical flexibility. However, reports of severe adverse reactions due to the transfusion of contaminated PCs led to an examination of whether the total bacteria levels after storage of pools containing a deliberately inoculated platelet unit would be significantly different than the levels in paired unpooled concentrates.

STUDY DESIGN AND METHODS

A single PC was deliberately inoculated on Day 0 with one of three bacterial species (0.1-8.0 colony-forming units/mL). On Day 1, the deliberately inoculated PC was divided into three equal parts and either 1) pooled with 5 half-volume, ABO- and Rh-identical PCs; 2) similarly pooled and white cell reduced; or 3) kept as a control. Sterile connections were used during pooling; modified storage containers were used to ensure the correct surface-to-volume ratio of the single unit.

RESULTS

Between Day 2 and Day 5 of storage, in 26 of 36 paired samples, nonfiltered pools containing Escherichia coli had greater total numbers of bacteria than did the paired single PCs. Day 2 pools had total bacteria levels approximately five times higher (colony-forming units/mL x container volume) than those in single units (p < 0.05). There was rapid growth of Staphylococcus aureus by Day 2 in pooled and unpooled PCs; by Day 3, total bacteria levels were approximately five times higher in pools than in single units (p < 0.05). Between Days 3 and 5 of storage, in 23 of 27 paired samples, nonfiltered pools containing S. aureus had greater total bacteria levels than the single PCs. By Day 5, 15 of 16 non-white-cell reduced pools had total levels of Staphylococcus epidermidis bacteria approximately five times those in the paired single PCs. Greater total bacteria levels in pooled units than in single units generally occurred when bacteria in pools reached the stationary phase of growth (when bacteria concentration became constant), and they were well correlated with the sixfold volume of pooled units. White cell reduction did not substantially affect the time required to attain stationary phase.

CONCLUSION

The potential during storage for greater total bacteria levels in pools than in single PCs is a consequence of the greater volume of the pool.

Major histocompatibility complex susceptibility genes for dermatitis herpetiformis compared with those for gluten-sensitive enteropathy

Dermatitis herpetiformis (DH) shares some clinical features and major histocompatibility complex (MHC) markers with gluten-sensitive enteropathy (GSE). We compared MHC haplotypes in 27 patients with DH, 35 patients with GSE, and normal controls. As in GSE, the frequencies of two extended haplotypes, [HLA-B8, SC01, DR3] and [HLA-B44, FC31, DR7], were increased in patients with DH. Distributions of fragments of extended haplotypes, consisting of some but not all of the elements of complete extended haplotypes, were analyzed to attempt to localize a susceptibility gene. Besides complete extended susceptibility haplotypes, (DR3, DQ2) and (DR7, DQ2) fragments were most common in GSE. In contrast, DH showed only a few such fragments but many instances of the fragment (SC01). The differences in distribution of these fragments in the two diseases were highly significant (P < 0.002). HLA-DQ2 and DR3 had the highest odds ratios for GSE, but the highest odds ratio for DH was for the complotype SC01. These findings suggest that the MHC susceptibility gene for DH is between class II and complotype regions, closest to the complotype, whereas that for GSE is in the class II region.

Effect of temperature on frequencies of spots in Drosophila wing-spot assay

The effect of temperature on spontaneous mutation frequencies was studied in the Drosophila somatic mutation and recombination test. Transdihybrid mwh +/+ flr3 larvae were grown at various temperatures (15, 18, 20, 22, 25, 27, and 29 degrees C) in the absence of any chemical mutagen. Wings of surviving adults were removed and scored for presence of small single spots, large single spots, and twin spots. No significant effect of temperature was found on mean frequency per wing of twin spots. Similarly, no significant effect of temperature was found for large singles within the temperature range of 18-29 degrees C; however, at 15 degrees C, the mean frequency per wing of large spots was significantly elevated. A significant quadratic relationship was found between mean frequency of small spots and temperature. Frequency of small spots per wing was minimized within the temperature range of 20-27 degrees C and increased at higher and lower temperatures. Maximum frequency of small spots per wing was observed at 15 degrees C. The qualitative nature of the small single spots induced at high and low temperatures is unclear; they may represent slow-growing segmentally aneuploid (deleted) cells or possibly even monosomic cells. Both heat and cold were found to be mutagenic in the Drosophila wing-spot assay. However, the mutagenic potency associated with temperature was much less than that of most chemical mutagens, and no significant effect of temperature was observed in the range of 20-27 degrees C.

Relationship of common laboratory parameters to the activity of Crohn's disease in children

The Pediatric Crohn's Disease Activity Index (PCDAI) has been proposed as a simple instrument to aid in the classification of patients by disease severity. The PCDAI includes subjective patient reporting of symptoms, physical examination, nutritional parameters, and several common laboratory tests (hematocrit, erythrocyte sedimentation rate, albumin). In this report we examine the relationship of each of the laboratory parameters to the PCDAI, as well as to a modified Harvey-Bradshaw Index score and physician global assessment of disease activity. Data were gathered from the clinical and laboratory observations from 133 children and adolescents at 12 pediatric gastroenterology centers in North America. A statistically significant relationship (p less than 0.05) was noted between each of the laboratory tests and the PCDAI for patients with either disease limited to the small bowel or in those with colonic involvement. For patients with disease limited to the small bowel, a statistically significant (p less than 0.05) relationship was also noted between the three laboratory parameters and the modified Harvey-Bradshaw Index and global assessment. For patients with large-bowel involvement, the erythrocyte sedimentation rate was statistically related to the modified Harvey-Bradshaw Index and global assessment (p less than 0.01), as was hematocrit to global assessment (p less than 0.01). Although the laboratory parameters used in the PCDAI appear to generally reflect disease activity in most patients, no single laboratory test is adequate to reflect disease activity in all patients. Future work will need to identify additional laboratory measures to reflect the inflammatory process and serve as important adjuncts in the assessment of disease activity.

Tetracycline-induced esophagitis in adolescent patients

Ulcerative esophagitis may be caused by corrosive agents and by commonly prescribed medications. We report severe esophagitis in five adolescents after ingestion of tetracycline preparations with minimal water immediately before going to bed.

Development and validation of a pediatric Crohn's disease activity index

Clinical and laboratory observations of 133 children and adolescents with Crohn's disease were used to validate an index of severity of illness previously developed by a group of senior pediatric gastroenterologists at a research forum in April 1990. This pediatric Crohn's disease activity index (PCDAI) included (a) subjective reporting of the degree of abdominal pain, stool pattern, and general well-being; (b) presence of extraintestinal manifestations, such as fever, arthritis, rash, and uveitis; (c) physical examination findings; (d) weight and height; and (e) hematocrit, erythrocyte sedimentation rate, and serum albumin. Independent evaluation of each patient by two physician-observers was performed at the time of a visit, and each physician completed a PCDAI index and a modified Harvey-Bradshaw index and made a "global assessment" of disease activity as none, mild, moderate, or severe. Excellent interobserver agreement was noted for the PCDAI, modified Harvey-Bradshaw index, and global assessment. There was a strong correlation between global assessment and both the PCDAI or modified Harvey-Bradshaw. Increasing PCDAI scores were noted with increasing disease severity, and significant differences in scores were noted between the severity groups. We propose that the PCDAI could be used in multicenter projects to facilitate patient stratification by disease severity and that longitudinal PCDAI scores might provide a numerical measure of response to therapeutic regimens.

Genetic prediction of nonresponse to hepatitis B vaccine

In previous studies of the antibody response to hepatitis B vaccine in 598 subjects who received a full course of vaccination, we observed a bimodal response, with about 14 percent producing less than approximately 1000 radioimmunoassay (RIA) units. An analysis of the major histocompatibility complex (MHC) HLA and complement types of 20 of the subjects with the lowest responses indicated a greater-than-expected number of homozygotes for the extended or fixed MHC haplotype [HLA-B8, SC01, DR3]. This finding suggested that the lack of a normal response was a recessive MHC-linked trait. In this study, we prospectively vaccinated five homozygotes and nine heterozygotes for this haplotype in the expectation that the homozygotes would produce much lower levels of antibody than the heterozygotes. When the antibody response was assessed two months after the third injection, four of the five homozygotes had produced very low levels (approximately 1000 units or less) of antibody (mean, 467 RIA units; range, less than 8 to 1266), whereas all nine heterozygotes produced more than 2500 RIA units (mean, 15,608; range, 2655 to 28,900) (P less than 0.01). We conclude that the usual response to hepatitis B surface antigen is due to the presence of a dominant immune-response gene in the MHC and that a low response is due to the absence of such a gene and the presence on both chromosomes of MHC haplotypes (such as [HLA-B8, SC01, DR3]) that indicate such a response.

Strategy for purification of coagulation factor concentrates

Advances in biotechnology are permitting significant changes in traditional plasma fractionation schemes. Increases in product purity, safety, and recovery are possible, and new products are being developed. Applications of technology to the purification of factor IX, factor X, protein C, antithrombin III, thrombin, and fibrin glue are described.

Thirty compounds tested in the Drosophila wing spot test

The Drosophila wing somatic mutation and recombination test (SMART) was evaluated for its suitability in genotoxicity screening by testing 30 chemicals. Of the 2 crosses used, the mwh-flr3 cross turned out to be more convenient than the previously used mwh-flr cross. Based on the experience gained with both acute exposures and chronic exposures of different duration, we suggest that the optimal strategy in genotoxicity screening is to start with chronic exposure of 3-day-old larvae for 48 h (that is, until pupation). Only for unstable compounds and very volatile compounds and gases are acute treatments, including inhalation, recommended. In general, a qualitative evaluation of the genotoxicity of a compound in the wing assay is possible with as few as 1-2 different exposure concentrations. A more quantitative evaluation of genotoxicity, based upon dose-response data, can often be achieved with as few as 3-4 concentrations. The results reported here were obtained in 2 different laboratories, demonstrating that the wing spot test is easily transferable to other laboratories. The experience gained indicates that the assay has now been developed to an extent that a coordinated international comparative validation study is desirable.

Inhalation of methyl bromide gas induces mitotic recombination in somatic cells of Drosophila melanogaster

The fumigant methyl bromide was evaluated for genotoxicity in the somatic wing-spot assay of Drosophila melanogaster. Third instar larvae trans-dihybrid for mwh and flr3 were exposed to varying concentrations (0-16 mg/l) of the gas for 1 h. Following this exposure via inhalation, the larvae were placed into vials containing Instant Medium. 7 days after the exposure, the adult flies in the vials were collected, and their wings were scored under 400X magnification for the presence of clones of cells possessing malformed wing-hairs. Such clones appeared as mwh-flr3 twin spots and single spots of either mwh or flr3 phenotype. Exposure to methyl bromide was found to result in the positive induction of both twin spots and large (greater than 2 cells) single spots. For each endpoint, a significant exponential association was obtained between concentration and frequency of spots per wing. Methyl bromide was found to be a negative inducer of small (1-2 cells) single spots at all concentrations except 16 mg/l where a positive effect was observed. Because twin spots arise exclusively from mitotic recombination, methyl bromide was identified as having recombinogenic activity in the somatic tissue of Drosophila larvae.

Extended major histocompatibility complex haplotypes in patients with gluten-sensitive enteropathy

We have studied major histocompatibility complex markers in randomly ascertained Caucasian patients with gluten-sensitive enteropathy and their families. The frequencies of extended haplotypes, defined as haplotypes of specific HLA-B, DR, BF, C2, C4A, and C4B allelic combinations, occurring more frequently than expected, were compared on patient chromosomes, on normal chromosomes from the study families, and on chromosomes from normal families. Over half of patient chromosomes consisted almost entirely of two extended haplotypes [HLA-B8, DR3, SC01] and [HLA-B44, DR7, FC31] which, with nonextended HLA-DR7, accounted for the previously observed HLA markers of this disease: HLA-B8, DR3, and DR7. There was no increase in HLA-DR3 on nonextended haplotypes or in other extended haplotypes with HLA-DR3 or DR7. The distribution of homozygotes and heterozygotes for HLA-DR3 and DR7 was consistent with recessive inheritance of the major histocompatibility complex-linked susceptibility gene for gluten-sensitive enteropathy. On the other hand, by odds ratio analysis and from the sum of DR3 and DR7 homozygotes compared with DR3/DR7 heterozygotes, there was an increase in heterozygotes and a decrease in homozygotes suggesting the presence of modifying phenomena.

Milk-sensitive and eosinophilic gastroenteropathy: similar clinical features with contrasting mechanisms and clinical course

We studied 12 children with peripheral eosinophilia, iron deficiency anemia secondary to blood loss in the stools, protein-losing enteropathy, and eosinophilic infiltration of the stomach and small intestine. On the basis of immunologic features and responses to therapy, these patients could be divided into two groups. In the first group the disease was transient, presented in the first year of life, remitted on withdrawal of milk from the diet, and was not associated with IgE-mediated immediate hypersensitivity (milk-sensitive enteropathy). In contrast, the second group, which we termed eosinophilic gastroenteropathy, represented patients with a chronic disease that had its onset later in childhood, did not respond to dietary manipulations, was associated with atopy and IgE-mediated immediate hypersensitivity reactions to food, and required corticosteroid therapy to establish remission and control. The mechanism by which food causes gastrointestinal damage appears to be different in these two groups even though the clinical syndromes are similar.

Relationships between structures and mutagenic potencies of 16 heterocyclic nitrogen mustards (ICR compounds) in Salmonella typhimurium

16 heterocyclic nitrogen mustards (ICR compounds), which were synthesized for use as possible antitumor agents by Creech and coworkers, were tested for mutagenicity in Salmonella typhimurium strains TA1535, TA1536, TA1537, TA1538, TA98 and TA100. The compounds were incorporated into the top agar at 5 doses: 0.5, 1, 2.5, 5 and 10 micrograms/plate. All of the compounds were negative in TA1535 except ICR 449, which was positive in all 6 strains. The other 15 compounds were positive in the remaining strains with the following exceptions: ICR 371 and 355 were negative in TA100; ICR 445 was negative in TA98 and TA100; and ICR 360 was negative in TA1537, TA1538, TA98 and TA100. Good qualitative agreement was observed between the mutagenic and antitumor activities of the 16 compounds, and between the mutagenic and carcinogenic activities of the 5 compounds that have been tested for carcinogenicity by Peck and coworkers. However, no significant correlation was found between mutagenic potency in Salmonella and antitumor potency in mice for the 16 compounds. Also, for the 5 compounds that have been tested for carcinogenicity, no significant correlation was found between their mutagenic potency in Salmonella and their carcinogenic potency in mice. In Salmonella, the secondary (2 degrees) amines generally were more mutagenic than their tertiary (3 degrees) amine homologs, although the opposite result has been reported in certain eukaryotes. Relationships between structures and potencies for the different nuclei of the 16 ICR compounds are discussed, as are similarities and differences in strain sensitivities. We conclude that the Salmonella his reversion test is not a good predictor of the antitumor and carcinogenic potencies of these ICR compounds.

Mutation tests in Neurospora crassa. A report of the U.S. Environmental Protection Agency Gene-Tox Program

Many mutation tests have been developed in Neurospora crassa during the almost 40 years of its use in mutation research. These tests detect two major classes of mutation: gene mutation and meiotic nondisjunction. Within the first class, forward- and reverse-mutation tests have been used. The forward-mutation tests include those that detect mutations at many loci and at specific loci. Both kinds of forward-mutation tests have been done in homokaryons (n) and heterokaryons (n + n'). From the publications that were not rejected by our pre-established criteria, data were extracted for 166 chemicals that had been tested for mutagenicity. Only 6 of the 166 chemicals have been tested in one or more gene mutation test and the meiotic nondisjunction test; these 6 chemicals were positive in the first and negative in the second. Of the 102 chemicals tested in one or more gene mutation tests, 94 were positive and 8 were negative. Of the 70 chemicals tested in the meiotic nondisjunction test, 7 were positive and 63 were negative. Two tests, the ad-3 forward-mutation test and the meiotic nondisjunction test, have been used most frequently. These two tests are especially important for hazard evaluation, because each detects a class of mutations that is likely to be deleterious or lethal in the F1 - disomics by the meiotic nondisjunction test and multilocus deletions by the ad-3 forward-mutation test in heterokaryons. Generally, direct-acting chemicals are mutagenic in the gene mutation tests, but few chemicals that required metabolic activation have been tested. Only 31 of the 166 chemicals tested in N. crassa have been tested for carcinogenicity. Among these chemicals, there is a good association between mutagenicity in gene mutation tests and carcinogenicity but a poorer association between meiotic nondisjunction and carcinogenicity; however, only a small number of chemicals has been tested in the meiotic nondisjunction test. Further use and development of certain mutation tests in N. crassa are desirable.