Antimicrobial resistance and virulence profiling of Staphylococcus pseudintermedius isolated from cats, Bangladesh

Staphylococcus pseudintermedius is a significant bacterial pathogen that frequently colonizes different body sites and mucous membranes of pets. The objectives of the cross-sectional study were to estimate the prevalence, antimicrobial resistance pattern, and detection of diverse resistance as well as virulence genes of S. pseudintermedius in cats. A standard bacteriological method, species-specific gene and different antimicrobial resistance as well as virulence genes were confirmed by PCR assay. A total of 233 swab samples were collected from different body sites of 102 cats, among them 146 swabs from 73 healthy cats, and 87 from 29 diseased cats. Overall, prevalence of S. pseudintermedius in cats was 12.01%, while dermatitis and otitis affected cats were 26.08% and 33.33%, respectively. The highest antimicrobial resistance was observed against penicillin (96.42%) followed by streptomycin (85.71%) and erythromycin (78.57%). Moreover, 89.28% of S. pseudintermedius isolates exhibit multi-drug resistance (MDR) (≥ 3 classes' antimicrobial resistant). In addition, 17.86% isolates harbored the mecA gene; thus, were classified as methicillin-resistant S. pseudintermedius (MRSP). Furthermore, the erythromycin resistance genes ermA and ermB were harbored by 25% and 10.71% of isolates, while 42.86% and 17.86% of isolates carried tetK and tetL (tetracycline resistance) genes, respectively. In virulence profiling, 32.14% (sea) and 10.71% (seb) of isolates were found positive for enterotoxin genes, whereas, the toxic shock syndrome toxin-1 (tst-1) gene and the Panton-Valentine leukocidin gene (pvl) were detected in 25% and 14.29% of isolates, respectively. To our knowledge, this is the first report of cats in Bangladesh for MDR S. pseudintermedius, MRSP, and their virulence profiling.

Novel use of an irrigated ablation catheter to monitor real-time hemodynamics during ablation

INTRODUCTION

Hemodynamic decompensation during catheter ablation occurs due to prolonged procedure time and irrigant delivery directly into the cardiac chambers. Real-time hemodynamic monitoring of patients undergoing catheter ablation procedures may identify patients at risk of decompensation; we set out to assess the feasibility of a novel, real-time, intracardiac pressure monitoring system using a standard irrigated ablation catheter.

METHODS

We studied 13 consecutive who underwent pressure measurement of the left atrium (LA) and left ventricle (LV) via transeptal access with a Swan Ganz (SG) catheter followed by two commercially available irrigated ablation catheters. Pressure waveform data was extracted to compare LA peak pressure, LV peak systolic pressure, LV end-diastolic pressure, and waveform analysis.

RESULTS

Comparison between the SG and ablation catheters (AblA; AblB) demonstrated that LV systolic pressure (0.61-16.8 mmHg; 1.32-18.2 mmHg), and LV end-diastolic pressure (-3.4 to 2.8 mmHg; -3.0 to 3.35 mmHg) were well correlated and had accepted repeatability. Ablation waveforms demonstrated an 89.9 ± 6.4% correlation compared to SG waveforms.

CONCLUSION

Pressure measurements derived from an irrigated ablation catheter are accurate and reliable when compared to an SG catheter. Further studies are needed to determine how real-time pressure monitoring can improve outcomes during ablation procedures.

POS1517-HPR PATIENT AND CLINICIAN PERSPECTIVES ON IMPLEMENTING THE RADAI-F5 TOOL TO HELP INFORM THE ASSESSMENT AND MANAGEMENT OF FOOT DISEASE IN RA: A QUALITATIVE STUDY

Background

While patient-reported outcome measures (PROMs) are widely recommended in clinical care, their application is limited [1]. The RADAI-F5 is a validated PROM to determine RA foot disease activity [2]. Patients’ and clinicians’ perceptions of the RADAI-F5’s clinical utility have yet to be captured.

Objectives

This study aims to explore patient and clinician opinions and perceptions of the clinical utility of the RADAI- F5’s in managing rheumatoid foot disease.

Methods

A 60-minute semi-structured interview using video conference calls with adult RA patients and rheumatologists, physiotherapists, and podiatrists was conducted as part of the interpretive phenomenological analysis research. The interviews included open-ended questions about the effect of foot disease, current clinical utilization of PROMS, and barriers and facilitators to the clinical application of the RADAI-F5. Inductive thematic data analysis with Nvivo12 identified emerging themes.

Results

Eight participants with rheumatoid arthritis: seven females; mean [standard deviation, SD] age 52.4 [9.5] years; mean [SD] disease duration 16.1 [16.4] years; eight clinicians; mean [SD] age 46.75 [5.3] years; mean [SD] years of clinical experience 19.5 [2.21] years. Four main themes were identified (Table 1); ‘Feet are a priority’ as the impact of RA on the feet was substantial and had a negative impact on quality of life. The second theme was ‘Need for a clinically feasible foot PROM’ as clinicians and patients recognised the lack of a clinically feasible tool that can determine RA foot disease. The third emerging theme was ‘RADAI-F5 facilitators’ as the tool can promote communication, guide management, help screen foot symptoms, monitor foot disease status and treatments longitudinally, and promote patient education. The final theme was ‘RADAI-F5 barriers’ as there were associated practical difficulties, including lack of appointment time, administrative burdens associated with PROM use, lack of trust in the RADAI-F5’s validity and IT barriers since there is no universal electronic system for reporting RADAI-F5 results.

Table 1.

Themes with respective quotes that emerged as part of the individual interviews to understand the clinical utility of the RADAI-F5

ThemeQuotationsTheme 1: Feet are important“Foot disease is common and it’s troublesome for patients” (C16) “I couldn’t see my friends because I was always so tired and in pain. It is very lonely.” (P07)Theme 2: Existing methods for measuring foot disease activity are inadequate“The feet are under-represented in the clinical tools for assessing disease activity, and clinicians don’t look at feet enough.” (C11)“We’ve tried numerous PROMS. Historically, I think probably it’s time-consuming for our clinical consultation”. (C12)Theme 3: RADAI-F5 facilitators“I think [The RADAI-F5] improves the clinician-patient relationship” (C15)“Using the RADAI-F5 could measure the success of the treatments that we are implicating.” (C12)Theme 4: RADAI-F5 barriers“I mean, this (RADAI-F5) will obviously go along with other tools. You know, the blood tests and things as well.” (P01)

Conclusion

The RADAI-F5 has significant potential as a therapeutic tool to aid in managing foot disease in RA. However, several implementation barriers need to be overcome before widespread use in rheumatology clinics can occur.

References

[1]Muradin I, van der Heide HJ. The foot function index is more sensitive to change than the Leeds Foot Impact Scale for evaluating rheumatoid arthritis patients after forefoot or hindfoot reconstruction. International orthopaedics. 2016; 40: pp.745-9.

[2]Hoque A, Gallagher K, McEntegart A, Porter D, Steultjens M, Woodburn J, Hendry GJ. Measuring Inflammatory Foot Disease in Rheumatoid Arthritis: Development and Validation of the Rheumatoid Arthritis Foot Disease Activity Index–5. Arthritis Care & Research. 2021;73: pp.1290-9.

Acknowledgements

Gordon Hendry, Diane Dickson and Martijn Steultjens

Disclosure of Interests

None declared

Antithyroid Antibody Status in Non-Pregnant Adult Bangladeshi Patients with Subclinical Hypothyroidism

Sub clinical hypothyroidism (SCH) is common in clinical practice. Autoimmunity is thought to be the most important cause of SCH. In this cross-sectional study, we investigated 120 SCH patients and 100 healthy controls attending the Endocrinology Outpatient Department of Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh from June 2014 to April 2015 for anti-thyroid antibodies (anti-TPO and anti-Tg). Measurement of serum TSH, FT4, anti-TPO, and anti-Tg antibodies were done by using the chemiluminescent sequential immunometric assay. SCH patients had a higher mean age; the frequencies of female subjects, those having family history of thyroid disease or other autoimmune diseases, and goiter were higher in SCH group than in the control group. Forty-five percent (45%) of SCH patients were positive for anti-thyroid antibodies (23.3% for both anti-TPO and anti-Tg, 16.7% for only anti-TPO, and 5% positive for only anti-Tg) in comparison to only 10% anti-thyroid antibody positive controls (none for both antibodies, 8% for only anti-TPO, and 2% positive for only anti-Tg). The SCH subjects in the lower age group, females and with a TSH >10μIU/mL had the higher frequency of thyroid autoimmunity. Female gender, high socioeconomic condition, the presence of other autoimmune diseases, the presence of goiter and TSH >10μIU/mL were associated with higher odds of anti-thyroid antibody positivity in the SCH group, though none were statistically significant. The frequency of anti-thyroid antibody was higher in SCH and was more prevalent among the females, younger patients and those having a goiter, other autoimmune diseases, and TSH >10μIU/mL.

Comparative Study between the Use of Multidose Standard Cardioplegia and Long Acting Del Nido Cardioplegia during Intracardiac Repair for Tetralogy of Fallot in Pediatric Patients

Pediatric myocardium is unique from mature myocardium; thus, the use of adult cardioplegia for pediatric cardiac operations may provide suboptimal myocardial protection. It is found that children undergoing heart surgery show evidence of less myocardial damage when del Nido cardioplegia is used instead of a standard cardioplegic solution. Del Nido cardioplegia solution provides a depolarized hyperkalaemic arrest lasting up to 60 minutes, reduces spontaneous and inducible activity during arrest, and prevents hyper contraction during early reperfusion. In this single blind randomized trial, a total of 60 patients underwent intra cardiac repair for TOF in National Institute of Cardiovascular Diseases, Dhaka, Bangladesh from July 2014 to January 2016 fulfilling inclusion and exclusion criteria. They were randomly assigned in two groups- 30 patients in Del Nido group (Group A) and 30 patients in standard group (Group B). Comparison between groups was done by Chi square test and Student's test. All data were analyzed by SPSS 20.0 for windows. P value less than 0.05 was considered as significant. There was statistically significant difference among the patients in terms of mean total initial cardioplegia volume, mean number of additional dose, mean additional dose amount, mean cross clamp time, mean CPB time (331.67±188.07 vs. 458.67±226.62, p=0.022; 0.13±0.35 vs. 1.27±0.89, p=0.000; 23.33±60.76 vs. 336.83±259.6, p=0.000; 45.10±10.35 vs. 59.23±23.21, p=0.003; 89.30±15.73 vs. 111.10±29.23, p=0.001 respectively). Mean post operative serum troponin I level at arrival in ICU and after 24 hours between two groups were statistically significantly different (55.60±32.91 vs. 83.5±58.99; p=0.024 and 13.01±5.84 vs. 18.16±9.51; p=0.014 respectively). The mean ventilation duration, mean ICU stay were also statistically significant. This study showed that cardiac arrest with Del Nido cardioplegia during intra cardiac repair for TOF was associated with improved myocardial protection over standard cardioplegia in terms of reduced CPB and cross clamp times, lower total volume of cardioplegia.

Emergence of multidrug-resistant NDM-1-producing Gram-negative bacteria in Bangladesh

The main objective of this study was to investigate the prevalence of bla (NDM-1) in Gram-negative bacteria in Bangladesh. In October 2010 at the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B) laboratories, 1,816 consecutive clinical samples were tested for imipenem-resistant Gram-negative organisms. Imipenem-resistant isolates were tested for the bla (NDM-1) gene. Among 403 isolates, 14 (3.5 %) were positive for bla (NDM-1), and the predominant species were Klebsiella pneumoniae, Acinetobacter baumannii, and Escherichia coli. All bla (NDM-1)-positive isolates were resistant to multiple antibiotics. Among β-lactamase genes, bla (CTX-M-1-group) was detected in ten isolates (eight bla (CTX-M-15)), bla (OXA-1-group) in six, bla (TEM) in nine, bla (SHV) in seven, and bla (VIM) and bla (CMY) in two isolates each. The 16S rRNA methylase gene, armA, was detected in five K. pneumoniae isolates and in one E. coli isolate. rmtB and rmtC were detected in a Citrobacter freundii and two K. pneumoniae isolates, respectively. qnr genes were detected in two K. pneumoniae isolates (one qnrB and one qnrS) and in an E. coli isolate (qnrA). Transferable plasmids (60-100 MDa) carrying bla (NDM-1) were detected in 7 of the 11 plasmid-containing isolates. Pulsed-field gel electrophoresis (PFGE) analysis grouped K. pneumoniae isolates into three clusters, while E. coli isolates differed significantly from each other. This study reports that approximately 3.5 % of Gram-negative clinical isolates in Bangladesh are NDM-1-producing.

Prevalence of stroke above forty years

Number of elderly persons gradually increased in Bangladesh due to improved health awareness and health care. Age is the single most important risk factor for stroke. This study aims at finding the prevalence of stroke in a Bangladeshi population aged forty years and above. The cases of stroke were ascertained in two phases of door-to-door survey. In phase-I, trained interviewers performed face-to-face interview with subjects for the detection stroke cases using the World Health Organization (WHO) screening protocol for neurological diseases. In phase-II, subjects suspected to have a stroke underwent a clinical evaluation for diagnosis or exclusion of stroke by a neurological team. The study involved 15627 participants aged 40 years and above. A total of 47 participants found to have stroke, expressing an overall prevalence rate of 3.00 per 1000 (95% CI 0.95 to 2.45). Prevalence of stroke were 2.0, 3.0, 2.0, 10.0, and 10.0 per 1000 within age groups of 40-49 years, 50-59 years, 60-69 years, 70-79 years and 80 years and above age group respectively. Prevalence of stroke in people with age range 70-79 years compared to 40-49 years age range is 4.988 (95% CI 2.309 to 10.77) times and people with age range ≥80 years compared to 40-49 years age range is 4.798 (95% CI 1.597 to14.416) times. Prevalence was higher among men in comparison with women. The male: female ratio is 3.44:2.41 per 1000 respectively. Bangladeshi male populations in rural areas are found to have stroke more than urban people. A large community based study should be undertaken to further confirm the result of this present study.

Epilepsy and abnormal electroencephalogram in children with autism spectrum disorder

Epilepsy occurs in 30 to 40% of individuals with autism spectrum disorder (ASD). However the association of epilepsy or abnormal electroencephalogram is not known in our population. This study addresses the incidence of epilepsy and or abnormal electroencephalogram in Bangladeshi children with autism spectrum disorder. The clinical history and electroencephalogram of 18 children diagnosed with autism spectrum disorder were retrospectively reviewed. Forty four percent were diagnosed with epilepsy or abnormal electroencephalogram. This abnormal electroencephalogram or epilepsy occurred at significantly higher rates in children with more impaired range of autism spectrum disorder. These finding suggest that the use of neurological investigative technique such as electroencephalogram (EEG) should be considered routinely in children with autism spectrum disorder especially in more impaired individuals.

Differential effects of peroxynitrite on the function of arginine vasopressin V1a receptors and alpha1-adrenoceptors in vivo

OBJECTIVE

The aim of this study was to provide evidence that peroxynitrite may differentially affect the function of arginine vasopressin (AVP) V(1a) receptors and alpha(1)-adrenoceptors in vascular smooth muscle of the rat

METHODS

The vasoconstrictor responses elicited by AVP, or the alpha(1)-adrenoceptor agonist, phenylephrine, were determined in anesthetized rats before and after injections of (i) peroxynitrite, the thiol chelator, para-hydroxymercurobenzoic acid (PHMBA), or the electron acceptor, nitroblue tetrazolium (NBT). The ability of the reducing agent, glutathione, to reverse the loss of response to phenylephrine and AVP in peroxynitrite-treated rats was also examined.

RESULTS

The AVP-induced responses were suppressed 10-20 min but not 60-70 min after the administration of peroxynitrite. Glutathione reversed the above loss of response to AVP at 10-20 min. The responses elicited by phenylephrine were suppressed 10-20 min and 60-70 min after administration of peroxynitrite. Glutathione did not reverse the above losses of response to phenylephrine. In addition, the vasoconstrictor actions of AVP and phenylephrine were markedly suppressed after administration of PHMBA or nitroblue tetrazolium.

CONCLUSIONS

The above findings provide evidence that exogenously administered peroxynitrite may differentially affect the function of AVP V(1a) receptors and alpha(1)-adrenoceptors in vascular smooth muscle of the rat. The possibility that peroxynitrite impairs AVP V(1a) receptor function by transient oxidation events whereas peroxynitrite impairs alpha(1)-adrenoceptor function by transient oxidation and permanent nitration events will be discussed.

Effects of Thiol Chelation on α1-Adrenoceptor-Induced Vasoconstriction In Vivo

The aims of this study were to determine whether systemic injections of the lipophobic thiol chelator, para-hydroxymercurobenzoic acid (PHMBA) would reduce the vasoconstrictor responses elicited by the alpha1-adrenoceptor agonist, phenylephrine, in urethane-anesthetized rats by chelation of thiol residues in alpha1-adrenoceptors in vascular smooth muscle rather than voltage-sensitive Ca(2+)-channels (Ca(2+)VERSUS-channels). The magnitudes and durations of the vasoconstrictor responses elicited by phenylephrine were markedly reduced after the injections of PHMBA. In contrast, the maximal phenylephrine-induced responses were not affected whereas the durations of these responses were markedly attenuated after injection of the Ca(2+)VERSUS-channel blocker, nifedipine. Nifedipine elicited pronounced and sustained falls in mean arterial blood pressure and vascular resistances in PHMBA-treated rats. Moreover, the vasodilator actions of the nitric oxide-donor, sodium nitroprusside were minimally attenuated by PHMBA whereas they were markedly attenuated by nifedipine. These findings support evidence that the vasoconstrictor responses due to activation of alpha1-adrenoceptors are initiated by mobilization of intracellular pools of Ca(2+) whereas they are sustained by opening of Ca(2+)VERSUS-channels. These findings also suggest that PHMBA diminishes the vasoconstrictor effects of phenylephrine by chelation of thiol residues in alpha1-adrenoceptors rather than by blockade of Ca(2+)VERSUS-channels, and that chelation of these thiol residues prevents agonist occupation and/or activation of these receptors and subsequent mobilization of intracellular pools of Ca(2+).

Differentiation of L- and D-S-Nitrosothiol Recognition Sites In Vivo

The main aim of this study was to determine the effects of the lipophobic electron acceptor, nitroblue tetrazolium (NBT), on the vasodilator responses elicited by femoral vein injections of L- and D-S-nitrosocysteine (L- and D-SNC), L- and D-S-nitroso-beta,beta-dimethylcysteine (L- and D-SNPEN) and the nitric oxide (NO) donor, MAHMA NONOate, in pentobarbital-anesthetized rats. L- and D-SNC, L- and D-SNPEN, and MAHMA NONOate elicited dose-dependent falls in mean arterial blood pressure (MAP), and hindquarter (HQR), renal (RR), and mesenteric (MR) vascular resistances. The L-SNC- and L-SNPEN-induced depressor and vasodilator responses were markedly attenuated after injection of NBT. The D-SNC- and D-SNPEN-induced falls in mean arterial pressure, hindquarter, and mesenteric vascular resistances were also reduced after injection of nitroblue tetrazolium whereas the falls in renal resistances were not affected. However, nitroblue tetrazolium inhibited the L-SNC and L-SNPEN responses much more profoundly than the D-SNC and D-SNPEN responses in each vascular bed. In contrast, the MAHMA NONOate-induced responses were not attenuated by nitroblue tetrazolium. This study demonstrates that nitroblue tetrazolium attenuates L- and D-SNC-and L- and D-SNPEN- mediated but not NO-mediated vasodilation. The lack of effects of NBT on the NO responses suggests that NBT does not interfere with the intracellular mechanisms by which NO relaxes vascular smooth muscle. The more pronounced effects of NBT on the vasodilator effects of L-SNC and L-SNPEN than D-SNC and D-SNPEN suggests that these stereoisomers differentially interact with stereoselective S-nitrosothiol recognition sites in the vasculature and that these sites (or their signaling elements) contain thiol residues that may be susceptible to occupation and/or oxidation (ie, disulfide-bond formation) by nitroblue tetrazolium.

Potential role of nitration and oxidation reactions in the effects of peroxynitrite on the function of β-adrenoceptor sub-types in the rat

This study examined the hemodynamic responses elicited by the beta-adrenoceptor agonist, isoproterenol (1 and 10 microg/kg, i.v.) before and after administration of (i) peroxynitrite (10 x 10 micromol/kg, i.v.), (ii) the thiol chelator, para-hydroxymercurobenzoic acid (pHMBA, 75 micromol/kg, i.v.), and (iii) the electron acceptor, nitroblue tetrazolium (NBT, 10 micromol/kg, i.v.) in pentobarbital-anesthetized rats. The tachycardia elicited by the lower dose of isoproterenol was diminished whereas the tachycardia elicited by the higher dose was not attenuated after administration of peroxynitrite. The falls in hindquarter and renal vascular resistances elicited by both doses of isoproterenol were substantially diminished whereas the isoproterenol-induced falls in mesenteric vascular resistance were not changed after administration of peroxynitrite. All of the isoproterenol-induced responses were markedly attenuated after administration of pHMBA or NBT. These findings suggest that the oxidation and/or nitration of beta-adrenoceptors impair the ability of isoproterenol to bind to and/or activate these G protein-coupled receptors. beta1-, beta2- and beta3-adrenoceptors contain extracellular cysteine residues susceptible to oxidation (i.e., disulfide-bridge formation) whereas only the beta1- and beta2-adrenoceptors contain extracellular tyrosine residues susceptible to nitration. These findings also suggest that sustained impairment of beta1- and beta2-adrenoceptor function by peroxynitrite is due to nitration of extracellular tyrosine residues in these receptors. By analogy, beta3-adrenoceptors may not be permanently affected by peroxynitrite because these receptors are devoid of extracellular tyrosine residues.

Two-dimensional and Doppler transesophageal echocardiographic delineation and flow characterization of anomalous coronary arteries in adults

OBJECTIVES

The purpose of this study was to examine the use of transesophageal echocardiography (TEE) in the identification and flow characterization of congenital coronary anomalies.

BACKGROUND

Congenital coronary anomalies in adults are rare but may cause serious cardiac complications. The use of TEE in evaluation of this entity has not been well defined. Very little is known regarding flow patterns in anomalous coronaries assessed by Doppler TEE.

METHODS

A total of 32 consecutive adult patients were studied using TEE to define the origin, course, and proximal flow pattern of suspected coronary anomalies.

RESULTS

Coronary anomalies identified using TEE included anomalous origin from the pulmonary trunk (n = 2), right sinus (n = 18), left sinus (n = 9), single coronary (n = 2), and left main coronary fistula (n = 1). Multiplane TEE performed in 20 cases simplified the delineation of more complex coronary anomalies. The origin was identified in all patients, proximal course delineated in 31, and proximal flow pattern characterized by pulsed Doppler in 23 of 32 patients. In 16 anomalous left main, left anterior descending, or left circumflex coronary arteries, an abnormal systolic flow pattern (ie, systolic/diastolic time-velocity integral ratio >1) occurred exclusively (P <.001) when the anomalous artery had an intermediate (100%; 5/5) versus anterior or posterior course (0%; 0/11) relative to the aortic and pulmonary artery trunks. A systolic flow pattern was also evident in 4 (80%) of 5 patients with an anomalous right coronary artery with an intermediate course.

CONCLUSIONS

TEE, particularly with a multiplane probe, has an important complementary role to coronary angiography in delineating the proximal course and pattern of flow in anomalous coronaries. Predominant systolic flow pattern in anatomically left proximal anomalous coronaries signifies an intermediate course between the aorta and the pulmonary trunk and may be clinically useful for risk stratification.

Exercise echocardiography and thallium-201 single-photon emission computed tomography stress test for 5- and 10-year prognosis of mortality and specific cardiac events

Limited data suggest that stress myocardial perfusion imaging and stress echocardiography have similar prognostic value for composite cardiac events. However, it is not known whether exercise echocardiography and stress thallium are similar in their prediction of specific cardiac events, eg, death, sudden death, myocardial infarction, unstable angina, and congestive heart failure. A total of 206 patients undergoing stress echocardiography and thallium-201 single-photon emission computed tomography imaging during the same exercise test were followed-up for 5 and 10 years. Multivariate Cox regression analyses incorporating clinical, exercise stress test, echocardiographic, and nuclear imaging parameters were used to predict mortality and specific cardiac events. A moderate to large amount of ischemia (> or =4 segments on the basis of a 16-segment model) by exercise stress echocardiography was the strongest predictor of overall mortality (relative risk [RR] 6.2; P <.0001), cardiac death (RR 17.6; P =.01), congestive heart failure (RR 17.4; P =.0005) or sudden death (RR 26.8; P =.003), whereas a moderate to large fixed defect (> or =2 segments on the basis of a 6-segment model) by nuclear imaging was the strongest predictor of myocardial infarction (RR 8.1; P =.0002) or unstable angina (RR 3.0; P =.005) at 5 years. The heterogeneity in the prediction of these specific cardiac events by these 2 modalities was similarly observed at 10 years. The extent of ischemia by stress echocardiography is a better predictor of overall mortality, cardiac death, congestive heart failure, or sudden death, whereas the extent of a fixed defect by nuclear imaging is a better predictor of myocardial infarction or unstable angina.

Regulation of the nitric oxide synthase-nitric oxide-cGMP pathway in rat mesenteric endothelial cells

Most of the available data on the nitric oxide (NO) pathway in the vasculature is derived from studies performed with cells isolated from conduit arteries. We investigated the expression and regulation of components of the NO synthase (NOS)-NO-cGMP pathway in endothelial cells from the mesenteric vascular bed. Basally, or in response to bradykinin, cultured mesenteric endothelial cells (MEC) do not release NO and do not express endothelial NOS protein. MEC treated with cytokines, but not untreated cells, express inducible NOS (iNOS) mRNA and protein, increase nitrite release, and stimulate cGMP accumulation in reporter smooth muscle cells. Pretreatment of MEC with genistein abolished the cytokine-induced iNOS expression. On the other hand, exposure of MEC to the microtubule depolymerizing agent colchicine did not affect the cytokine-induced increase in nitrite formation and iNOS protein expression, whereas it inhibited the induction of iNOS in smooth muscle cells. Collectively, our findings demonstrate that MEC do not express endothelial NOS but respond to inflammatory stimuli by expressing iNOS, a process that is blocked by tyrosine kinase inhibition but not by microtubule depolymerization.

Molecular epidemiologic studies within the Selenium and Vitamin E Cancer Prevention Trial (SELECT)

OBJECTIVE

To conduct timely epidemiologic investigations of molecular/genetic markers that may contribute to the development of prostate, lung, colorectal, or other cancers within the Selenium and Vitamin E Cancer Prevention Trial (SELECT), and to evaluate interactions between these markers and the study interventions.

METHODS

The epidemiologic studies within SELECT will be based on 32,400 men aged 55 years or older (age 50 or older for the African-American men) enrolled into an intergroup, randomized, placebo-controlled, double-blind, phase III prevention trial of supplemental selenium and vitamin E developed and funded by the National Cancer Institute, and coordinated by the Southwest Oncology Group. During the 12-year study period approximately 1500-2000 cases of prostate cancer, 800 lung cancers, and 500 colon cancers are estimated to be diagnosed, based on data from the ongoing Prostate Cancer Prevention Trial of finasteride. A modified fasting blood sample will be processed to collect plasma for analysis of micronutrients, hormones, cytokines, and other proteins. Buffy-coat derived white blood cells collected at baseline will be used for isolation of DNA and establishment of immortalized cell lines. Red blood cells will be stored for analysis of hemoglobin adducts and other components.

RESULTS

Specific results anticipated from these molecular studies will provide information on factors hypothesized to contribute to prostate cancer risk and that may modify the efficacy of either trial supplement, including: steroid sex hormones and several polymorphic genes that encode proteins affecting androgenic stimulation of the prostate, including the androgen receptor, steroid 5alpha-reductase type II, CYP17, and beta-hydroxysteroid dehydrogenase; polymorphisms of DNA repair genes and carcinogen metabolism genes, including those involved in the activation of chemical carcinogens to reactive intermediates (e.g., CYP1A1) or the detoxification of reactive intermediates (e.g., glutathione S-transferase M1); DNA and protein adducts; and insulin-like growth factors and leptin.

CONCLUSION

SELECT offers an excellent opportunity to conduct molecular epidemiologic investigations to assess gene-environment interactions and their role in prostate, lung, and colon carcinogenesis.

Computerized image analysis of Ki-67 in ductal breast carcinoma in situ

OBJECTIVE

To develop and determine the staining protocols and computerized image analysis methods that are the most effective combination for performing quantitative analysis of Ki-67.

STUDY DESIGN

We compared conventional bright-field light microscopy and refractive optical enhancement methods in combination with various immunodetection and filter enhancement methods, including immunogold in combination with epipolarization refractive optics and enzymatic conversion of chromogenic substrates in combination with optical filter enhancement. Initial Ki-67 tests were performed on lymph node tissues and cultured human breast cells and then applied to 200 ductal carcinoma in situ (DCIS) samples. DCIS acini were digitally acquired, and a region of interest was manually outlined in each one with a digital stylus to include only the cellular component; then the Ki-67 staining index was quantified by segmentation analysis.

RESULTS

Although combining epipolarization analysis with immunohistogold staining was the most sensitive detection method, nonspecific binding was too high. The streptavidin-horseradish-peroxidase enzymatic conversion of 3,3'-diaminobenzidine (DAB) in combination with optical enhancement filters was the most effective method tested. Ki-67 stain was associated with dense fibrillar structures of the nucleoli in the less intensely staining nuclei and was most intense in paired nuclei.

CONCLUSION

The method of measuring Ki-67 expression by DAB staining combined with optical enhancement filters and quantification via computer-assisted image analysis techniques produced objective and reproducible results. As such, this method can offer (1) less intraobserver and interobserver variability, (2) a digital archival record, and (3) a baseline for digital exchange of information between studies.

Quantitative nuclear morphometry by image analysis for prediction of recurrence of ductal carcinoma in situ of the breast

Clinical management of ductal carcinoma in situ (DCIS) remains a challenge because significant proportions of patients experience recurrence after conservative surgical treatment. Unfortunately, it is difficult to prospectively identify, using objective criteria, patients who are at high risk of recurrence and might benefit from additional treatment. We conducted a multi-institutional, collaborative case-control study to identify nuclear morphometric features that would be useful for identifying women with DCIS at the highest risk of recurrence. Tissue sections of archival breast tissue of 29 women with recurrent and 73 matched women with nonrecurrent DCIS were stained for DNA, and nuclei in the DCIS lesions were evaluated by image analysis. A clear correlation between mean fractal2_area (FA2) and nuclear grade was observed (P < 0.001), allowing an objective determination of nuclear grade. Several nuclear morphometric features, including mean and variance of variation of radius, mean area, mean and variance of frequency of high boundary harmonics (FQH), and variance in sphericity, were found to be useful in discriminating recurrent from nonrecurrent DCIS subjects. However, the nuclear features associated with recurrence differed between high- and low-grade lesions. For lesions with high FA2 (nuclear grade 3), mean variation of radius, mean FQH, and mean area alone yielded recurrence odds ratios of 4.55 [95% confidence interval (CI) 0.45-45.96], 3.86 (95% CI, 0.88-16.98), 2.90 (95% CI, 0.31-27.2), respectively. Using a summed feature model, high-FA2 lesions showing three poor prognostic features had an odds ratio of 15.63 (95% CI, 1.22-200), compared with those with zero or one poor prognostic feature. Lesions with low mean FA2 (nuclear grade 1 or 2) showing high variances in sphericity and FQH had an odds ratio of 7.71 (95% CI, 1.77-33.60). Addition of other features did not enhance the odds ratio or its significance. These results suggest that nuclear image analysis of DCIS lesions may provide an adjunctive tool to conventional pathological analysis, both for the objective assessment of nuclear grade and for the identification of features that predict patient outcome.

Blockade of voltage-sensitive Ca(2+)-channels markedly diminishes nitric oxide- but not L-S-nitrosocysteine- or endothelium-dependent vasodilation in vivo

The aim of this study was to determine the hemodynamic responses elicited by systemic injections of (i) the nitric oxide (NO)-donors, sodium nitroprusside (10 nmol/kg, i.v.) and (Z)-1-(N-methyl-N-(6(N-methylammoniohexyl)amino))diazen-1-ium-1, 2-diolate (MAHMA NONOate, 25 nmol/kg, i.v.), (ii) the endothelium-derived S-nitrosothiol, L-S-nitrosocysteine (100 nmol/kg, i.v.), and (iii) the endothelium-dependent agonist, acetylcholine (1.0 microg/kg, i.v.), in anesthetized rats, before and after injection of the voltage-sensitive Ca(2+)-channel (Ca(VS)(2+)-channel) blocker, nifedipine (500 nmol/kg, i.v.). Before injection of nifedipine, the agents produced similar falls in mean arterial blood pressure, and in hindquarter and mesenteric vascular resistances. The depressor and vasodilator responses elicited by sodium nitroprusside and MAHMA NONOate were markedly attenuated by nifedipine. The falls in mean arterial blood pressure and mesenteric resistance elicited by L-S-nitrosocysteine and acetylcholine were not attenuated but the falls in hindquarter resistance were slightly attenuated by nifedipine. The cyclooxygenase inhibitor, indomethacin (10 mg/kg, i.v.), did not affect the actions of sodium nitroprusside, MAHMA NONOate, L-S-nitrosocysteine or acetylcholine or the effects of nifedipine on the hemodynamic actions of these compounds. The decomposition of sodium nitroprusside (0.2 nmol/ml), MAHMA NONOate (0.5 nmol/ml) and L-S-nitrosocysteine (2 nmol/ml) to NO upon addition to rat blood was not affected by nifedipine (10 microM). These findings suggest that (i) exogenously applied NO relaxes resistance arteries in vivo by inhibition of Ca(VS)(2+)-channels whereas L-S-nitrosocysteine and the non-prostanoid endothelium-derived relaxing factor (EDRF) released by acetylcholine acts by additional mechanisms, and (ii) this EDRF may be an S-nitrosothiol which acts independently of its decomposition to NO.

Redox regulation of S-nitrosocysteine-mediated vasodilation in vivo

This study examined the effects of the lipophobic electron acceptor, nitroblue tetrazolium (2x5 micromol/kg, i.v.) on the vasodilation produced by the putative endothelium-derived S-nitrosothiol, L-S-nitrosocysteine (400 nmol/kg, i.v.), and the nitric oxide (NO) donor, (Z)-1-N-methyl-N-[6(N-methylammoniohexyl)amino]&z. sfnc;diazen-1-ium-1,2-diolate (MAHMA NONOate, 25 nmol/kg, i.v.), in anesthetized rats. The administration of nitroblue tetrazolium resulted in delayed but long-lasting increases in vascular resistances. The L-S-nitrosocysteine-induced vasodilator responses were markedly diminished whereas the MAHMA NONOate-induced responses were not affected by nitroblue tetrazolium. These results support the possibility that L-S-nitrosocysteine interacts with membrane thiols that are subject to nitroblue tetrazolium-induced oxidation (i.e., disulfide-bridge formation) and that nitroblue tetrazolium-induced vasoconstriction may involve a loss of potency of endothelium-derived S-nitrosothiols.

Does aflatoxin B1 play a role in the etiology of hepatocellular carcinoma in the United States?

Previous research showed that risk factors associated with hepatocellular carcinoma (HCC) include infection with hepatitis B (HBV) and hepatitis C (HCV) viruses, exposure to aflatoxin B1 (AFB1), and liver cirrhosis, due primarily to alcohol consumption. To determine whether AFB1 may play a role in HCC in the United States, a search for AFB1 adducts and p53 alterations, potentially induced by AFB1, was conducted in the United States in 23 HCC patients with available tissue samples. The presence of AFB1 tumor-DNA and -serum lysine adducts and mutant p53 product was determined by immunoassays and codon 249 p53 mutation by restriction enzyme analysis. HBV and HCV serology and serum HBV-DNA were also determined. Thirteen patients were positive for HBV by HBs antigen or anti-HBc antigen or by polymerase chain reaction for HBV-DNA sequences. Nine patients were free of HBV and HCV markers; 5 of 22 sera tested were anti-HCV positive. p53 Protein expression, determined by immunohistochemical staining, was present in 5 of the 23 tumor tissues, whereas p53 codon 249 mutations were not observed in the 5 cases in which tissue was available for study. AFB1 tumor-DNA adducts were present in 3 of 19 tumor tissues, and in 1 of these 3 samples p53 protein was also detected. Sera from only 5 of the patients were tested for AFB1-lysine adducts, and all were positive. In these five patients, neither p53 protein nor a mutation on codon 249 was detected. The demonstration that AFB1-DNA and -lysine adducts are present in HCC patients in the United States is intriguing but requires further substantiation because of the small number of subjects in this pilot study. To elucidate the pathogenetic significance of these findings, further investigation, including studies in larger patient cohorts and properly selected controls, is warranted.

In vivo evidence that L-S-nitrosocysteine may exert its vasodilator effects by interaction with thiol residues in the vasculature

This study examined the effects of the lipophobic thiol chelator, para-hydroxymercurobenzoic acid (25 and 50 micromol/kg, i.v.) on the falls in mean arterial blood pressure and regional vascular resistances produced by L-S-nitrosocysteine (400 nmol/kg, i.v.) and the nitric oxide (NO)-donors, (Z)-1-&z. sfnc;N-methyl-N-[6(N-methylammoniohexyl)amino]&z.sfnc; diazen-1-ium-1, 2-diolate (MAHMA NONOate, 25 nmol/kg, i.v.) and sodium nitroprusside (10 microg/kg, i.v.), in urethane-anesthetized rats. The L-S-nitrosocysteine-induced responses were markedly diminished whereas the MAHMA NONOate- and sodium nitroprusside-induced responses were minimally affected by para-hydroxymercurobenzoic acid. These results suggest that the vasodilator actions of L-S-nitrosocysteine involves the interaction with membrane thiols in vascular smooth muscle of resistance arteries and that para-hydroxymercurobenzoic acid does not markedly affect NO-mediated vasodilation.

Durable clinical and pathologic response of hepatocellular carcinoma to systemic and hepatic arterial administration of platinol, recombinant interferon alpha 2B, doxorubicin, and 5-fluorouracil: a communication

The case described here illustrates the antitumor activity of a four-drug systemic combination chemobiotherapy with platinol, recombinant interferon alpha 2b, doxorubicin (Adriamycin), and 5-fluorouracil (5-FU) (PIAF) in a patient with diffuse hepatocellular carcinoma involving the liver and lungs.

Interobserver reproducibility of the Lagios nuclear grading system for ductal carcinoma in situ

Several studies have shown an association between high nuclear grade or necrosis of ductal carcinoma in situ (DCIS) lesions and the risk of local disease recurrence in patients with DCIS treated surgically with less than mastectomy. Although criteria for separating low from high nuclear grade lesions have been published, no information exists regarding interobserver reproducibility (IR). To assess IR in the classification of DCIS, six surgical pathologists from four institutions used the Lagios grading system to grade 125 DCIS lesions. Before meeting to evaluate the cases, a training set of 12 glass slides, including cases chosen to present conflicting cues for classification, was mailed to the participants with a written criteria summary. This was followed by a working session in which criteria were reviewed and agreed on. The pathologists then graded the lesions independently. The area of interest was marked on each slide before grading. After initial grading, the pathologists met again to resolve discrepant lesion classifications. A complete agreement among raters was achieved in 43 (35%) cases, with five of six raters agreeing in another 45 (36%) cases. In no case did two raters differ by more than one grade. The pairwise kappa agreement values ranged from fair to substantial (0.30 to 0.61). Generalized kappa value indicated moderate agreement (0.46, standard error = 0.02). Kappa statistics for the distinction between grades 1 and 2 and 2 and 3 were 0.29 and 0.48, respectively, (standard error = 0.02). Only one of the six raters differed significantly in scoring. With adherence to specific criteria, IR in the classification of DCIS cases can be obtained in most cases. Although these pathologists made a few grading system modifications, further refinements are needed, especially if grading will influence future therapy.

Cancer among a Michigan cohort exposed to polybrominated biphenyls in 1973

The long-term health effects of human exposure to polybrominated biphenyls are not known. In this nested case-control study, we evaluated the association between site-specific cancer risk and serum polybrominated biphenyl levels among a Michigan cohort accidentally exposed to polybrominated biphenyls in 1973. The Michigan Department of Public Health has followed 3,899 people through 1993, among whom 195 primary cancers were identified in 187 persons. Controls were 696 randomly selected cancer-free individuals who were frequency matched to cases by sex and age (in 5-year strata). Baseline serum polybrominated biphenyl levels were measured using standard methods. We found an increasing dose-response relation for digestive system cancer risk with higher serum polybrominated biphenyl category [4-20 parts per billion (ppb), 21-50 ppb, and > 50 ppb] after adjustment for age, family cancer history, cigarette smoking, alcohol drinking, and baseline serum polychlorinated biphenyl level. Adjusted odds ratios (ORs) for each category were 8.23 [95% confidence interval (CI) = 1.27-53.3], 12.3 (95% CI = 0.80-191), and 22.9 (95% CI = 1.34-392), respectively. Univariate analysis for polybrominated biphenyl level and lymphoma risk also showed a dose-response relation, with corresponding ORs of 3.24 (95% CI = 0.24-95.9), 20.5 (95% CI = 1.51-608), and 32.6 (95% CI = 3.33-861).

Phase II trial of hepatic arterial infusion of fluorouracil and recombinant human interferon alfa-2b for liver metastases of colorectal cancer refractory to systemic fluorouracil and leucovorin

PURPOSE

To determine the toxicity, response rate, and survival in patients treated with hepatic arterial infusion (HAI) of fluorouracil (5-FU) plus recombinant human interferon alfa-2b (rIFN-alpha 2b) (Intron-A; Schering-Plough, Inc, Kenilworth, NJ) for colorectal carcinoma (CRC) liver metastases refractory to systemic 5-FU plus leucovorin (LCV).

PATIENTS AND METHODS

Forty-eight patients were given a 6-hour HAI of rIFN-alpha 2b 5 MU/m2 followed by an 18-hour HAI of 5-FU, 1,500 mg/m2 daily for 5 days. Twenty-nine patients were treated through percutaneously placed catheters and 19 through implantable infusion pumps (Shiley Infusaid Inc, Noorwood, MA). Treatment cycles were repeated every 28 to 35 days.

RESULTS

There were three (6.6%) complete remissions (CRs) and 12 (26.6%) partial remissions (PRs), for a CR plus PR rate of 33.3% among 45 assessable patients (95% confidence interval [CI], 20% to 49%). The median response duration was 7 months, while median survival duration was 15 months. Grade 3 to 4 treatment-related toxic effects included mucositis (40%), neutropenia (42%), and thrombocytopenia (12%). No hepatobiliary toxicity was encountered in any of the patients. Treatment was discontinued because of progressive liver disease in 23 patients and extrahepatic progression in 16, while six patients continue treatment through an infusaid pump.

CONCLUSION

HAI of 5-FU plus rIFN-alpha 2b is well tolerated, devoid of hepatobiliary toxicity, and can produce a response rate of 33.3% among patients refractory to bolus intravenous (IV) 5-FU plus LCV. The lack of hepatobiliary toxicity may permit salvage HAI with floxuridine (FUDR) in patients whose liver tumors fail to respond to HAI of 5-FU plus rIFN-alpha 2b. Because diarrhea was not a common side effect of HAI of 5-FU plus rIFN-alpha 2b, it would be of interest to investigate whether alternating HAI of 5-FU and rIFN-alpha 2b with systemic irinotecan (CPT-11) will decrease the incidence of both hepatic and extrahepatic disease progression.

Birth practice patterns in urban slums of Dhaka, Bangladesh

This study describes the patterns of birth related practices amongst women from an urban slum population in Dhaka city during December 1988 to May 1989. A household census identified all resident women of childbearing age in Rajabazar ward of Dhaka city. Of the 1017 women so identified, 289 women who had given birth to their last child over the previous five years were randomly selected for interview using a structured interview schedule. To observe actual birth practices, sixteen women pregnant for six months or more at the time of the census were followed-up to the immediate post-natal period. Eight local traditional birth attendants (TBAs) were interviewed informally to obtain insights about birthing techniques. A case study for a typical 'normal' delivery is presented and discussed.

In vitro propagation of Rauvolfia serpentina through tissue culture

Multiple shoots were induced from nodal segments and shoot apices of Rauvolfia serpentina and MS medium containing 1.0 mg/l BA and 0.1 mg/l NAA was found to give the best shoot proliferation rate. Callus formed at cut bases of the explants which produced shoots when subcultured on media containing low concentration of BA (0.5 or 0.1 mg/l) and NAA (0.1 mg/l). The in vitro proliferated shoots were rooted and later transferred to the soil.

Phase II trial of intravenous flourouracil and subcutaneous interferon alfa-2b for biliary tract cancer

PURPOSE

To assess the efficacy of systemic intravenous-fluorouracil (5-FU) and subcutaneous recombinant human interferon alfa-2b (rIFN alpha-2b) in patients with measurable cancer of the biliary tree.

PATIENTS AND METHODS

Thirty-five patients (25 with cholangiocarcinoma and 10 with gallbladder carcinoma) were registered onto this phase II protocol between 1992 and 1995. Patients received a continuous infusion of 750 mg/m2/d of 5-FU on days 1 through 5 through a centrally placed venous catheter and a subcutaneous injection of 5 MU/m2 of rIFN alpha-2b on days 1, 3, and 5. Treatment cycles were repeated every 14 days; one course of therapy included four treatment cycles. Disease status was assessed every 8 weeks. Dosages were lowered for grade III mucositis. Fourteen patients had prior treatment and, before initiating this therapy, 17 patients required decompression of the biliary tree.

RESULTS

Eleven of 32 (34%) assessable patients had a partial response. The median time to disease progression was 9.5 months, and the median survival time 12 months. Grade III to IV toxic effects were granulocytopenia (14%), mucositis (20%), diarrhea (9%), and dermatitis (11%). Grade III to IV asthenia and fatigue were observed in 6% of patients.

CONCLUSION

Drug tolerance was better among previously untreated patients. To achieve a complete response, additional chemotherapy or radiotherapy should be considered when liver resection or transplantation is not feasible. However, if these results can be reproduced by other investigators, the regimen should be studied for adjuvant treatment of gallbladder carcinoma incidentally identified in patients undergoing cholecystectomy.

Phase II study of paclitaxel therapy for unresectable biliary tree carcinomas

PURPOSE

To evaluate the efficacy of paclitaxel administered to patients with unresectable adenocarcinomas of the gallbladder and biliary tree over 3 hours every 21 days.

PATIENTS AND METHODS

Fifteen patients with unresectable and/or metastatic carcinoma of the gallbladder and bile ducts received intravenous paclitaxel over 3 hours after premedication with dexamethasone, diphenhydramine, and cimetidine. Treatment was repeated every 21 days, and one complete course of therapy was comprised of two such 21-day treatment cycles. The initial dose of paclitaxel was 170 mg/m2, and this was elevated to 200 mg/m2 due to tolerance within the initial patient cohort.

RESULTS

All patients were assessable for both toxicity and response: 11 with bile duct cancer and four with gall-bladder carcinoma. Forty-three cycles of therapy were delivered during the trial (median, two), and one patient remains on treatment. No complete or partial responses were noted, although two patients achieved minor responses that lasted 2 and 2+ months, respectively. There were no deaths on this study, and all but one of the patients is still alive. The therapy was well tolerated, and hematologic and mucosal toxic effects were moderate and readily reversible, although significant neuromuscular adverse effects were noted.

CONCLUSION

These findings indicate that paclitaxel, administered on this schedule, is tolerable, but is unlikely to have activity in metastatic carcinomas of the biliary tree. It is unclear whether a different regimen of paclitaxel, or another taxane, may have activity in these neoplasms.

A phase I evaluation of chronotropic delivery of floxuridine by hepatic arterial infusion in patients with metastatic colorectal cancer

Hepatic arterial infusion (HAI) of floxuridine is often used for metastatic colorectal cancer, though this is associated with dose-limiting hepatobiliary toxicity. A phase I trial was initiated to determine if circadian-patterned HAI floxuridine would reduce toxicity. Twenty-one patients were enrolled, and they received a continuous 14-day HAI of floxuridine, with 90-95% of the drug delivered over the same six-hour period daily. The therapy was tolerable, but there was no reduction in hepatobiliary toxicity. The response rate of 33% (1 complete and 6 partial responses) was similar to that of regimens that do not utilize circadian timing. HAI floxuridine chronotherapy for metastatic colorectal cancer cannot be recommended.

Mutagen sensitivity as a risk factor for second malignant tumors following malignancies of the upper aerodigestive tract

BACKGROUND

Second malignant tumors in patients successfully treated for an initial cancer of the upper aerodigestive tract are an important cause of morbidity and mortality. Biologic markers capable of identifying high-risk subgroups of patients who could be targeted for intensive clinical surveillance, therefore, have immense therapeutic and prognostic relevance. We previously demonstrated in a pilot study of 84 patients with cancers of the upper aerodigestive tract that mutagen sensitivity was a significant predictor of risk of developing second malignant tumors.

PURPOSE

We extended the study to include 278 patients diagnosed with previously untreated cancers of the upper aerodigestive tract from 1987 to August 1993.

METHODS

For each patient, base-line (pretreatment) mutagen sensitivity was measured in vitro in 50 metaphases established from peripheral lymphocyte cultures. Patients with an average of more than 1 chromosomal break/cell were deemed mutagen hypersensitive. Cox proportional hazards analysis was used to predict the risk of developing second malignant tumors associated with mutagen sensitivity.

RESULTS

Overall, 44% of the case group exhibited mutagen hypersensitivity. There were no differences in the distribution of mutagen hypersensitivity by site, sex, stage of disease, or smoking status. There were 17 synchronous and 11 metachronous cancers, of which 15 (54%) were smoking-related malignancies. Sixteen (13.1%) of the mutagen-sensitive patients developed second malignant tumors, compared with 12 (7.7%) of the nonsensitive patients. The mean break/cell value (+/- SD) for patients developing second malignant tumors was 1.17 (+/- 0.54), compared with 0.98 (+/- 0.44) for patients with only one cancer (P = .04). Mutagen hypersensitivity conferred a relative risk of 2.67 (95% confidence interval = 1.22-5.79) of developing second malignant tumors.

CONCLUSIONS

Mutagen hypersensitivity increases the risk of developing second malignant tumors.

IMPLICATIONS

Future research should focus on the molecular mechanisms underlying mutagen sensitivity.

Patterns of physical growth in a longitudinal study of young children in rural Bangladesh

Longitudinal field studies of the physical growth of 197 children between 6 and 60 months of age have been completed in two rural villages of Bangladesh. The distribution of weights by age indicated that 90% of the village girls and boyd weighed less than the National Center for Health Statistics 5th percentile by 8 and 15 months of age, respectively. Of the children 90% were shorter than the reference population 10th percentile length by age by 10 to 13 months of age. Since the children's patterns of growth differed from those of the reference populations from North America and Europe, internal standards were created for the village girls and boys by fitting curves to their data for weight by age, length by age, arm circumference by age, triceps skinfold thickness by age, and weight by length. The village references enabled age-independent comparisons of children within the study population by relating their actual anthropometric status to the village norms. Comparisons of the village standards with the international reference data showed the period of poorest nutritional status of the village children persisted from shortly after birth to approximately 2 yr of age.