Subjective perception of paraesthesia of the lower lip after bilateral sagittal split osteotomy at a district general hospital.

Our aim was to assess patients' perception of paraesthesia of the lower lip after bilateral sagittal split osteotomy (BSSO) at a district general hospital. Patients who had BSSO between August 2013 and August 2014 (n=46) were asked to score their perception of numbness between 0-10 (0=normal sensation. 10=complete loss of sensation/total numbness) one day postoperatively and then weekly for seven weeks, and at three months, 6 months, and one year. Data was collected on score sheets and by regular contact by telephone. Of the 46 operated on, 31 were female and 15 male. Data were available one year postoperatively for 43 patients. Ten of the 92 sides were reported as feeling normal on day 1 postoperatively, three-quarters as feeling normal at six months, and 79 at one year. On multivariate analysis there was no significant difference in postoperative sensation at one year between sides operated on by the registrar (left) and consultant (right) operated (p=0.76). Our results compared favourably with the limited data available in similarly designed studies.

Root resistance to cavitation is accurately measured using a centrifuge technique.

Plants transport water under negative pressure and this makes their xylem vulnerable to cavitation. Among plant organs, root xylem is often highly vulnerable to cavitation due to water stress. The use of centrifuge methods to study organs, such as roots, that have long vessels are hypothesized to produce erroneous estimates of cavitation resistance due to the presence of open vessels through measured samples. The assumption that roots have long vessels may be premature since data for root vessel length are sparse; moreover, recent studies have not supported the existence of a long-vessel artifact for stems when a standard centrifuge technique was used. We examined resistance to cavitation estimated using a standard centrifuge technique and compared these values with native embolism measurements for roots of seven woody species grown in a common garden. For one species we also measured vulnerability using single-vessel air injection. We found excellent agreement between root native embolism and the levels of embolism measured using a centrifuge technique, and with air-seeding estimates from single-vessel injection. Estimates of cavitation resistance measured from centrifuge curves were biologically meaningful and were correlated with field minimum water potentials, vessel diameter (VD), maximum xylem-specific conductivity (Ksmax) and vessel length. Roots did not have unusually long vessels compared with stems; moreover, root vessel length was not correlated to VD or to the vessel length of stems. These results suggest that root cavitation resistance can be accurately and efficiently measured using a standard centrifuge method and that roots are highly vulnerable to cavitation. The role of root cavitation resistance in determining drought tolerance of woody species deserves further study, particularly in the context of climate change.

Dietary restriction of lycopene for a period of one month resulted in significantly increased biomarkers of oxidative stress and bone resorption in postmenopausal women.

BACKGROUND AND OBJECTIVES: Lycopene is a carotenoid commonly found in tomatoes and tomato products which acts as an antioxidant to decrease oxidative stress and osteoporosis risk. We wanted to determine the effects of a lycopene-restricted diet on oxidative stress parameters and bone turnover markers in postmenopausal women. SETTING: St. Michael 's Hospital, Toronto, ON, Canada. PARTICIPANTS AND STUDY DESIGN: 23 healthy postmenopausal women, 50-60 years old, provided blood samples at baseline and following a one-month lycopene-depletion period. MEASUREMENTS: Serum samples were analyzed for carotenoids; the oxidative stress parameters protein thiols and thiobarbituric-malondialdehyde reactive substances; the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), and the bone turnover markers bone alkaline phosphatase and crosslinked N-telopeptide of type I collagen (NTx). A paired t-test was used to test for significant differences in bone turnover markers, oxidative stress parameters and antioxidant status after lycopene restriction. RESULTS: Dietary lycopene restriction resulted in significantly decreased serum lycopene (p < 0.0001), lutein/zeaxanthin (p < 0.01), and α -/ß -carotene (p < 0.05). GPx (p < 0.01), lipid and protein oxidation increased (not significant), while CAT and SOD were significantly depressed (p < 0.05 and p < 0.005, respectively). These changes coincided with significantly increased NTx (p < 0.05). CONCLUSIONS: These findings suggest that the daily consumption of lycopene may be important as it acts as an antioxidant to decrease bone resorption in postmenopausal women and may therefore be beneficial in reducing the risk of osteoporosis.

Supplementation with the antioxidant lycopene significantly decreases oxidative stress parameters and the bone resorption marker N-telopeptide of type I collagen in postmenopausal women.

UNLABELLED: To date, no intervention studies have been published demonstrating the effect of the antioxidant lycopene on bone. Postmenopausal women supplemented with lycopene had significantly increased antioxidant capacity and decreased oxidative stress and the bone resorption marker N-telopeptide (NTx). Lycopene decreases bone resorption markers and may reduce the risk of osteoporosis. INTRODUCTION: We have previously shown in vitro and in vivo that lycopene from tomato is associated with a protective effect on bone, but lycopene intervention studies have not been reported. Our aim was to carry out a randomized controlled intervention study to determine whether lycopene would act as an antioxidant to decrease oxidative stress parameters, resulting in decreased bone turnover markers, thus reducing the risk of osteoporosis in postmenopausal women. METHODS: Sixty postmenopausal women, 50-60 years old, were recruited. Following a 1-month washout without lycopene consumption, participants consumed either (N = 15/group): (1) regular tomato juice, (2) lycopene-rich tomato juice, (3) tomato Lyc-O-Mato lycopene capsules, or (4) placebo capsules, twice daily for total lycopene intakes of 30, 70, 30, and 0 mg/day respectively for 4 months. Serum collected after the washout, 2 and 4 months of supplementation, was assayed for cross-linked aminoterminal N-telopeptide, carotenoid content, total antioxidant capacity (TAC), lipid, and protein oxidation. RESULTS: Participants who consumed juice or lycopene capsules were analyzed in one group designated "LYCOPENE-supplemented". Repeated measures ANOVA showed that LYCOPENE-supplementation for 4 months significantly increased serum lycopene compared to placebo (p < 0.001). LYCOPENE-supplementation for 4 months resulted in significantly increased TAC (p < 0.05) and decreased lipid peroxidation (p < 0.001), protein oxidation (p < 0.001), and NTx (p < 0.001). These decreases in lipid peroxidation, protein oxidation, and NTx were significantly different from the corresponding changes resulting from placebo supplementation (p < 0.05, p < 0.005, and p < 0.02, respectively). CONCLUSIONS: Our findings suggest that the antioxidant lycopene is beneficial in reducing oxidative stress parameters and the bone resorption marker NTx.

Paraoxonase 1 polymorphisms 172T→A and 584A→G modify the association between serum concentrations of the antioxidant lycopene and bone turnover markers and oxidative stress parameters in women 25-70 years of age.

BACKGROUND/AIMS: Polymorphisms of the paraoxonase 1 (PON1) enzyme affect the ability to protect LDL from oxidation. Oxidative stress is a risk factor for osteoporosis and antioxidants may be beneficial for prevention. The aim of this study was to determine whether PON1 genotypes modified the association between lycopene and bone turnover markers and oxidative stress parameters. METHODS: Blood samples from 107 women 25-70 years of age were analyzed for serum carotenoid concentrations, bone-specific alkaline phosphatase (BAP), N-telopeptide of type I collagen (NTx) and oxidative stress parameters. Subjects were genotyped for the 172T→A and 584A→G polymorphisms of PON1. RESULTS: The 172T→A polymorphism modified the association between lycopene and NTx (p < 0.05 for interaction). In the 172TT genotype, high serum lycopene was associated with decreased NTx (p < 0.05). The 584A→G polymorphism modified the association between lycopene and BAP (p < 0.05 for interaction). Additionally, in participants with the 584GG genotype, high serum lycopene was associated with high TBA-reactive substances (p < 0.05). CONCLUSIONS: These findings show that PON1 polymorphisms modify the association between serum concentrations of lycopene and oxidative stress parameters and bone turnover markers and may, therefore, moderate the risk of osteoporosis.

Evaluation of the processes of family-centred care for young children with intellectual disability in Western Australia.

INTRODUCTION: Government early intervention services for children with intellectual disability (ID) in Western Australia have adopted the model of family-centred care. The aim of this study was to evaluate how well it was being practised, to describe the pattern of service utilization and to identify factors influencing parental perceptions of family-centred care. METHODS: The study included children aged 0-6 years with ID, who were registered clients of Disability Services Commission, Western Australia. Parents completed a postal survey questionnaire about the frequency and type of services received and their perceptions of services using the Measure of Processes of Care (MPOC-56) questionnaire. Mean scores for the five MPOC domains were compared using anova against the independent variables of child age group, child diagnostic group, service type and frequency, place of residence, family and demographic variables. Significant variables in each domain were then entered into multivariate analyses. RESULTS: Of 292 eligible families, 165 (59%) returned a completed questionnaire. While over 50% of children had contact with occupational, speech and physical therapists at least once per month, less than 20% of children had at least annual contact with either psychology or dental services. Families rated their satisfaction highest for 'respectful and supportive care' and lowest for 'providing general information'. Individual item analyses indicated less satisfaction with 'co-ordinated and comprehensive care'. Higher means were associated with more frequent contact with occupational therapy. CONCLUSION: Overall respondents reported early intervention services for young children with ID in Western Australia provided satisfactory family-centred care by means of the 56-item MPOC. The frequency of contact with allied health professionals was positively associated with parental ratings of family-centred care. The study indicates under-servicing in dental care and psychology services.

Lycopene intake by Canadian women is variable, similar among different ages, but greater than that reported for women in other countries.

Lycopene is an antioxidant associated with a reduced risk of chronic diseases common in women such as osteoporosis and cancer; however, no official recommendation for lycopene consumption exists, and intake data from Canadian women are limited. This study was designed to generate information about average lycopene intake in Canadian women of different ages. A cross-sectional study was conducted at St. Michael's Hospital in Toronto, Ontario, Canada. One hundred one women, between the ages of 25 and 70 years, who were not on any medications, were recruited to record their diet for 7 days. Statistical analyses were performed to compare the types of lycopene-containing foods consumed, associations between intake of lycopene and macro/micronutrients, and whether participant characteristics, such as body mass index, could predict lycopene intake. Average lycopene intake was 6.14 +/- 5.35 mg/day, which is higher than reported in other countries. Intake was similar among age groups but was highly variable. Raw tomatoes were the most frequently consumed source of lycopene, while participants with the highest lycopene intake consumed more cooked/processed tomato products than those with lower intake (P < .005). Participants 25-49 years old consumed more dried/powdered tomatoes (P < .05), pizza (P < .002), and ketchup (P < .10) than 50-70 year olds. Lycopene intake could not be predicted by any participant characteristics. In older participants, lycopene intake was positively correlated with intake of calcium, niacin, and vitamins A, D, and K (P < or = .05). These findings are significant to women's health and may contribute to the establishment of nutritional and health recommendations regarding consumption of lycopene by Canadian women to prevent chronic diseases.

Lycopene consumption decreases oxidative stress and bone resorption markers in postmenopausal women.

INTRODUCTION: Oxidative stress induced by reactive oxygen species (ROS) is associated with the risk of osteoporosis, and can be reduced by certain dietary antioxidants. Lycopene is an antioxidant known to decrease the risk of age-related chronic diseases, such as cancer. However, the role of lycopene in osteoporosis has not yet been investigated. MATERIALS AND METHODS: In a cross-sectional study, 33 postmenopausal women aged 50-60 years provided seven-day dietary records and blood samples. Serum samples were used to measure serum lycopene, lipid peroxidation, protein thiols, bone alkaline phosphatase (BAP), and cross-linked N-telopeptides of type I collagen (NTx). The serum lycopene per kilogram body weight of the participants was grouped into quartiles and associated with the above serum parameters using one-way ANOVA and the Newman-Keuls post-test. RESULTS: The results showed that groups with higher lycopene intake, as determined from the dietary records, had higher serum lycopene (p<0.02). A higher serum lycopene was found to be associated with a low NTx (p<0.005). Similarly, groups with higher serum lycopene had lower protein oxidation (p<0.05). DISCUSSION: In conclusion, these results suggest that the dietary antioxidant lycopene reduces oxidative stress and the levels of bone turnover markers in postmenopausal women, and may be beneficial in reducing the risk of osteoporosis.

Effects of radiotherapy and of differences in the extent of surgery for early breast cancer on local recurrence and 15-year survival: an overview of the randomised trials.

BACKGROUND: In early breast cancer, variations in local treatment that substantially affect the risk of locoregional recurrence could also affect long-term breast cancer mortality. To examine this relationship, collaborative meta-analyses were undertaken, based on individual patient data, of the relevant randomised trials that began by 1995. METHODS: Information was available on 42,000 women in 78 randomised treatment comparisons (radiotherapy vs no radiotherapy, 23,500; more vs less surgery, 9300; more surgery vs radiotherapy, 9300). 24 types of local treatment comparison were identified. To help relate the effect on local (ie, locoregional) recurrence to that on breast cancer mortality, these were grouped according to whether or not the 5-year local recurrence risk exceeded 10% (<10%, 17,000 women; >10%, 25,000 women). FINDINGS: About three-quarters of the eventual local recurrence risk occurred during the first 5 years. In the comparisons that involved little (<10%) difference in 5-year local recurrence risk there was little difference in 15-year breast cancer mortality. Among the 25,000 women in the comparisons that involved substantial (>10%) differences, however, 5-year local recurrence risks were 7% active versus 26% control (absolute reduction 19%), and 15-year breast cancer mortality risks were 44.6% versus 49.5% (absolute reduction 5.0%, SE 0.8, 2p<0.00001). These 25,000 women included 7300 with breast-conserving surgery (BCS) in trials of radiotherapy (generally just to the conserved breast), with 5-year local recurrence risks (mainly in the conserved breast, as most had axillary clearance and node-negative disease) 7% versus 26% (reduction 19%), and 15-year breast cancer mortality risks 30.5% versus 35.9% (reduction 5.4%, SE 1.7, 2p=0.0002; overall mortality reduction 5.3%, SE 1.8, 2p=0.005). They also included 8500 with mastectomy, axillary clearance, and node-positive disease in trials of radiotherapy (generally to the chest wall and regional lymph nodes), with similar absolute gains from radiotherapy; 5-year local recurrence risks (mainly at these sites) 6% versus 23% (reduction 17%), and 15-year breast cancer mortality risks 54.7% versus 60.1% (reduction 5.4%, SE 1.3, 2p=0.0002; overall mortality reduction 4.4%, SE 1.2, 2p=0.0009). Radiotherapy produced similar proportional reductions in local recurrence in all women (irrespective of age or tumour characteristics) and in all major trials of radiotherapy versus not (recent or older; with or without systemic therapy), so large absolute reductions in local recurrence were seen only if the control risk was large. To help assess the life-threatening side-effects of radiotherapy, the trials of radiotherapy versus not were combined with those of radiotherapy versus more surgery. There was, at least with some of the older radiotherapy regimens, a significant excess incidence of contralateral breast cancer (rate ratio 1.18, SE 0.06, 2p=0.002) and a significant excess of non-breast-cancer mortality in irradiated women (rate ratio 1.12, SE 0.04, 2p=0.001). Both were slight during the first 5 years, but continued after year 15. The excess mortality was mainly from heart disease (rate ratio 1.27, SE 0.07, 2p=0.0001) and lung cancer (rate ratio 1.78, SE 0.22, 2p=0.0004). INTERPRETATION: In these trials, avoidance of a local recurrence in the conserved breast after BCS and avoidance of a local recurrence elsewhere (eg, the chest wall or regional nodes) after mastectomy were of comparable relevance to 15-year breast cancer mortality. Differences in local treatment that substantially affect local recurrence rates would, in the hypothetical absence of any other causes of death, avoid about one breast cancer death over the next 15 years for every four local recurrences avoided, and should reduce 15-year overall mortality.

The anterior mediastinal approach for management of tracheomalacia.

BACKGROUND: Tracheomalacia occurs as a primary developmental defect or may be secondary to vascular compression. It is common in association with esophageal atresia and tracheoesophageal fistula. Collapse of the weak trachea is a cause of recurrent respiratory symptoms but may be severe and life threatening. METHODS: Between 1978 and 1999 at Sheffield Children's Hospital and The Royal Manchester Children's Hospital, of 16 children with clinically significant symptoms of tracheomalacia 8 underwent combined aortopexy and tracheopexy, 1 had aortopexy alone, 4 only had a tracheopexy, and 3 had tracheal reinforcement with free costal cartilage ring grafts. The surgical approach was limited to a low cervical skin crease incision with a midline manubrial split providing extrapleural access to the anterior mediastinum and allowing for all surgery under direct unimpaired vision. RESULTS: Ten children did not require postoperative ventilatory support. Four underwent ventilation for a few hours or days. One child required CPAP for 4 months for residual tracheomalacia and a further child, who had 3 operations to insert 11 costal cartilage ring grafts, underwent ventilation intermittently for 6 months. Adequate tracheal patency could be verified by intraoperative tracheoscopy and was sustained postoperatively so that only 1 child with associated bilateral vocal cord paralysis came to tracheostomy. Four children required prolonged hospitalization because of residual tracheomalacia, 2 for bronchomalacia and 2 because of esophageal narrowing leading to further surgery. All other children were fit for discharge within 10 to 30 days of surgery. Long-term follow-up has confirmed sustained tracheal improvement and resolution of the life-threatening features of tracheomalacia. CONCLUSIONS: The authors recommend the low skin crease transmanubrial approach, as described by Vaishnav and MacKinnon, for tracheopexy, aortopexy and for tracheal reconstruction for tracheomalacia. The approach gives excellent access for surgery under direct vision through a relatively avascular plane. It is associated with less morbidity than a conventional thoracotomy and leaves a more acceptable aesthetic scar.

A review of intensive care nurse staffing practices overseas: what lessons for Australia?

In view of market-driven health-care policies and the move to greater efficiencies within the health-care system, the cost of nursing care is being increasingly scrutinised. Different overseas practices are commonly cited as justification for changing practices within Australia. This study is based on a review of the literature on intensive care nurse staffing requirements in Australasia; specifically, New South Wales, the United States (US) and, to a lesser extent, Europe. It was found that looking to the US for cost-cutting strategies in intensive care units (ICUs) is based on a false premise: that we are comparing like with like. ICUs in the US have a different historical trajectory and culture, service wider constituencies, have technicians and unregistered personnel providing nursing care and do not provide demonstrably better outcomes or significant cost savings. Research indicates that continuous nursing care by trained professionals provides the best outcomes. If costs must be cut, technology, pharmaceuticals and laboratory tests should be targeted. Further, a greater commitment to the development of a 'progressive patient care' model in hospital planning is required, in order to establish or consolidate an intermediate level of nursing care between the ward and the ICU. Programs aiming to improve and continuously monitor patient care, such as adverse event monitoring, the prevention of unplanned extubation and facilitation of early extubation, should be instituted, as these have been shown to not only reduce ICU costs but also improve patient outcomes. (c) 2000 Harcourt Publishers Ltd.

Success in life for older adolescents with cerebral palsy.

In this article, the psychosocial themes emerging from an exploratory qualitative study are reported. Using a constant comparative method, the authors describe how older adolescents with cerebral palsy defined success in life and the factors they viewed as helping or hindering their success. Participants were 10 adolescents with cerebral palsy between 18 and 20 years of age who took part in a semistructured interview exploring their perceptions of success. For these adolescents, success meant being happy in life. Three key psychosocial factors were related to success in life: being believed in, believing in yourself, and being accepted by others (belonging). The findings are useful in guiding the design of services to meet the life needs of individuals with disabilities.

Measuring outcomes in children's rehabilitation: a decision protocol.

OBJECTIVE: To develop and test the feasibility and clinical utility of a computerized self-directed software program designed to enable service providers in children's rehabilitation to make decisions about the most appropriate outcome measures to use in client and program evaluation. DESIGN: A before-and-after design was used to test the feasibility and initial impact of the decision-making outcome software in improving knowledge and use of clinical outcome measures. SETTING: A children's rehabilitation center in a city of 50,000. PARTICIPANTS: All service providers in the children's rehabilitation center. Disciplines represented included early childhood education, occupational therapy, physical therapy, speech and language pathology, audiology, social work, and psychology. INTERVENTION: Using a conceptual framework based on the International Classification of Impairment, Disability, and Handicap (ICIDH), an outcome measurement decision-making protocol was developed. The decision-making protocol was computerized in an educational software program with an attached database of critically appraised measures. Participants learned about outcome measures through the program and selected outcome measures that met their specifications. The computer software was tested for feasibility in the children's rehabilitation center for 6 months. OUTCOME MEASURES: Knowledge and use of clinical outcome measures were determined before and after the feasibility testing using a survey of all service providers currently at the centre and audits of 30 randomly selected rehabilitation records (at pretest, posttest, and follow-up). RESULTS: Service providers indicated that the outcomes software was easy to follow and believed that the use of the ICIDH framework helped them in making decisions about selecting outcome measures. Results of the survey indicated that there were significant changes in the service providers' level of comfort with selecting measures and knowing what measures were available. Use of outcome measures as identified through the audit did not change. CONCLUSIONS: The "All About Outcomes" software is clinically useful. Further research should evaluate whether using the software affects the use of outcome measures in clinical practice.

A review of intensive care nurse staffing practices overseas: what lessons for Australia?

In view of market-driven health-care policies and the move to greater efficiencies within the health-care system, the cost of nursing care is being increasingly scrutinised. Different overseas practices are commonly cited as justification for changing practices within Australia. This study is based on a review of the literature on intensive care nurse staffing requirements in Australasia; specifically, New South Wales, the United States (US) and, to a lesser extent, Europe. It was found that looking to the US for cost-cutting strategies in intensive care units (ICUs) is based on a false premise: that we are comparing like with like. ICUs in the US have a different historical trajectory and culture, service wider constituencies, have technicians and unregistered personnel providing nursing care and do not provide demonstrably better outcomes or significant cost savings. Research indicates that continuous nursing care by trained professionals provides the best outcomes. If costs must be cut, technology, pharmaceuticals and laboratory tests should be targeted. Further, a greater commitment to the development of a 'progressive patient care' model in hospital planning is required, in order to establish or consolidate an intermediate level of nursing care between the ward and the ICU. Programs aiming to improve and continuously monitor patient care, such as adverse event monitoring, the prevention of unplanned extubation and facilitation of early extubation, should be instituted, as these have been shown to not only reduce ICU costs but also improve patient outcomes.

Experience with surgery for continence in children with a neuropathic bladder.

We report our experience of surgery for continence in a series of 23 children with a neuropathic bladder. Overall good results were obtained (85.7% continent). The complications and their management are discussed.

Nucleotide sequence of the p74 gene of a baculovirus pathogenic to the spruce budworm, Choristoneura fumiferana multicapsid nuclear polyhedrosis virus.

Polypeptide p74 has been found to be essential for production of virulent occlusion bodies of the baculovirus Autographa californica multicapsid nuclear polyhedrosis virus (AcMNPV). Hybridization with AcMNPV-derived probes has led to the location of the p74 gene in the spruce budworm virus, Choristoneura fumiferana MNPV. Sequence data indicate that CfMNPV p74 is 73% identical to AcMNPV at the nucleotide level and 77% identical at the amino acid level. Elements of predicted secondary structure are also conserved.

An unusual virus from the parasitic wasp Cotesia melanoscela.

Certain strains of the braconid parasitoid Cotesia melanoscela carry two different viruses within their ovaries, one of which (here designated CmV2) is apparently not a polydnavirus. Virus replication occurs in the ovarian calyx and in some other tissues of both male and female parasitoids; as yet, no replication has been observed in the testis, however. In addition, CmV2 is one of only two parasitoid viruses known to replicate in host insect larvae, and we not show that this virus is also capable of replicating in vitro; the virus is nevertheless nonpathogenic for gypsy moth larvae. The virus is not transmissible per os, either to host animals or to larvae of parasitoid strains lacking it. CmV2 is stably maintained within strains carrying it apparently by a vertical transmission mode involving the maternal line; transmission via the male germ line could not be demonstrated. While purification of the virus was not achieved, preliminary work allows us to suggest the genome consists of a single double-stranded DNA molecule of approximately 125 kb.

Variation between homologues and sister chromatids in individual karyotypes.

Chromatid absolute length and density profile from electron micrograph images of human group A chromosomes were studied in an attempt to identify significant individual karyotypic variation. The variation within sister chromatids can be utilized as an internal standard to establish a limit of variability for the purpose of demonstrating differences between homologues. Homologous chromosomes were found to differ with respect to absolute length and density profile.

Image analysis of the acetic acid-alcohol fixed metaphase chromosome.

Electron micrographs of acetic acid-alcohol fixed, unstained human metaphase chromosomes have been analyzed with an image system. Electron micrographs were first digitized from over a million picture elements into a range of 64 gray levels which correspond to mass distribution. The obtained numerical data were then processed by programs which increased contrast and permitted enhancement and expansion of the original image. Despite the disruptive nature of such preparations, analysis of their TEM images reveals structural features previously reported from other preparative methods as well as morphological properties previously reported in metaphase chromosomes which required special pretreatments and staining for demonstration. Familial features included low density centromeres and secondary constrictions, higher density telomeres and paracentromeric regions, and G-band-like differential densities along chromatids. In addition, structural components were observed in a size range 25-56 nm. These masses appeared to have linear and circular forms oriented in perpendicular, diagonal and longitudinal arrays. They appeared in a nonrandom fashion and can be interpreted as demonstrating a relatively ordered chromosome.

Mutagenicity of N-nitroso derivatives of carbofuran and its toxic metabolites.

Carbofuran (CF), an insecticide and nematocide, is metabolically oxidized to two less toxic forms, 3-hydroxycarbofuran and 3-ketocarbofuran. The N-nitroso derivatives of carbofuran and its metabolites were synthesized by reaction with nitrite under acidic conditions. Products of the reaction were obtained by extraction, identified by thin-layer chromatography, and purified by silica gel column chromatography. All three nitroso derivatives reacted positively with Gries reagent and gave characteristic triplet absorption spectra (387, 402, and 422 nm). Structural confirmation was by nuclear magnetic resonance and mass spectroscopy. Mutagenicity was determined by the Ames assay method with Salmonella typhimurium strains TA98 and TA100. The nitroso derivatives of all three compounds responded similarly, given a mutation ratio of 45 at 5 micrograms per plate on TA100. In addition, all three produced chromosome aberrations in Chinese hamster ovary (CHO) cells. Only two of the three (nitrosocarbofuran and 3-hydroxynitrosocarbofuran) were also capable of inducing large numbers of sister chromatid exchanges in the same cells. Observed variations in maximum mutagenicity in the Ames test and the ability to induce sister chromatid exchanges in CHO cells are consistent with the stability of the compounds in aqueous solution.