Toxicity and Efficacy of Stereotactic Ablative Body Radiotherapy for Moderately Central Non-small Cell Lung Cancers Using 50 Gy in Five Fractions

AIMS

Stereotactic ablative body radiotherapy doses for peripheral lung lesions caused high toxicity when used for central non-small cell lung cancer (NSCLC). To determine a safe stereotactic ablative body radiotherapy dose for central tumours, the phase I/II Radiation Therapy Oncology Group RTOG 0813 trial used 50 Gy/five fractions as a baseline. From 2013, 50 Gy/five fractions was adopted at the Beatson West of Scotland Cancer Centre for inoperable early stage central NSCLC. We report our prospectively collected toxicity and efficacy data.

MATERIALS AND METHODS

Patient and treatment characteristics were obtained from electronic medical records. Tumours were classed as moderately central or ultra-central tumours using published definitions. Toxicity was assessed in a centralised follow-up clinic at 2 weeks, 6 weeks, 3 months, 6 months, 1 year and 2 years after treatment.

RESULTS

Fifty patients (31 women, 19 men, median age 75.1 years) were identified with T1-2N0M0 moderately central NSCLC; one patient had both an ultra-central and a moderately central tumour. Eighty-four per cent were medically unfit for surgery. Forty per cent had biopsy-proven NSCLC and 60% were diagnosed radiologically using 18-fluorodeoxyglucose positron emission tomography/computed tomography imaging. Fifty-six per cent of patients were Eastern Cooperative Oncology Group (ECOG) performance status 2 or worse. All patients received 50 Gy/five fractions on alternate days on schedule. Two patients died within 90 days of treatment, one from a chest infection, the other cause of death was unknown. There was one episode of early grade 3 oesophagitis and one grade 3 late dyspnoea. There was no grade 4 toxicity. Over a median follow-up of 25.2 months (range 1-70 months), there were 34 deaths: 18 unrelated to cancer and 16 due to cancer recurrence. The median overall survival was 27.0 months (95% confidence interval 20.6-35.9) and cancer-specific survival was 39.8 months (95% confidence interval 28.6, not reached).

CONCLUSION

This study has shown that 50 Gy/five fractions is a safe dose and fractionation for early stage inoperable moderately central NSCLC, with outcomes comparable with other series, even with patients with a poor performance status.

SYSTEMS-2: A randomised phase II study of radiotherapy dose escalation for pain control in malignant pleural mesothelioma

SYSTEMS-2 is a randomised study of radiotherapy dose escalation for pain control in 112 patients with malignant pleural mesothelioma (MPM). Standard palliative (20 Gy/5#) or dose escalated treatment (36 Gy/6#) will be delivered using advanced radiotherapy techniques and pain responses will be compared at week 5. Data will guide optimal palliative radiotherapy in MPM.

Associates of change in liver fat content in the morbidly obese after laparoscopic gastric banding surgery

AIM

Hepatic steatosis affects up to 30% of the population. After weight loss, monitoring of the change in hepatic steatosis is not routinely performed. This study aimed to define the closest associates of change in liver fat content in a population of obese females following laparoscopic gastric banding surgery.

METHODS

Before and 3 months after surgery, proton magnetic resonance spectroscopy and magnetic resonance imaging were used to estimate the amount of lipid contained within the liver and abdominal subcutaneous and visceral compartments of 29 obese [mean body mass index (BMI) 39 +/- 5 kg/m(2)], non-diabetic women aged between 20 and 62 years. Liver enzymes, fasting plasma glucose and insulin were also measured as well as body weight, BMI and waist circumference. Insulin sensitivity was estimated using homeostasis model assessment insulin resistance index.

RESULTS

Significant reductions occurred in body weight (p < 0.001), abdominal fat volumes (p < 0.001) and liver fat (p = 0.037) 3 months after surgery. Change in liver fat content more closely associated with change in serum gamma-glutamyl transferase (GGT; r = 0.71, p < 0.001) than with changes in weight (r = 0.10, p = 0.612) and waist circumference (r = 0.15, p = 0.468).

CONCLUSIONS

Our findings suggest that obese non-diabetic female patients who have undergone significant weight loss over 3 months can be better assessed for the regression of excess liver fat content by monitoring changes in serum GGT levels rather than changes in simple anthropometry.

Reproductive and developmental toxicity of inhaled 2,3-dichloro-1,3-butadiene in rats

Inhalation developmental and reproductive toxicity studies were conducted with 2,3-dichloro-1,3-butadiene (DCBD), a monomer used in the production of synthetic rubber. In the reproductive toxicity study, Crl:CD(SD)IGS BR rats (24/sex/group) were exposed whole body by inhalation to 0, 1, 5, or 50 ppm DCBD (6 h/day) for approximately 10-11 weeks total, through premating (8 weeks; 5 days/week), cohabitation of mating pairs (up to 2 weeks, 7 days/week), post-cohabitation for males (approximately 7 days) and from conception to implantation (gestation days 0-7 [GD 0-7]), followed by a recovery period (GD 8-21) for presumed pregnant females. Estrous cyclicity was evaluated during premating (last 3 weeks) and cohabitation. Reproductive organs and potential target organs, sperm parameters, and GD 21 fetuses (viability, weight, external alterations) were evaluated. In the developmental study, pregnant Crl:CD(SD)IGS BR rats (22/group) were exposed whole body by inhalation to 0, 1, 10, or 50 ppm DCBD (6 h/day) on GD 6-20; dams were necropsied on GD 21 (gross post-mortem only) and fetuses were evaluated (viability, weight, and external, visceral and skeletal exams). During the in-life portion of the studies, body weight, food consumption, and clinical observation data were collected. At 50 ppm, gasping and labored breathing occurred in both studies during the first few exposures; body weight and food consumption parameters were affected in parental animals from both studies, but were more severely affected in the developmental study. Fetal weight was decreased in the developmental study at 50 ppm. Degeneration of the nasal olfactory epithelium was observed in the reproduction study at 50 ppm. There were no effects on reproductive function, embryo-fetal viability, or increases in fetal structural alterations in either study. The no-observed-adverse-effect level (NOAEL) for reproductive toxicity was 50 ppm. The NOAEL for systemic toxicity in the reproduction study was 5 ppm based on adverse effects on body weight and food consumption parameters and nasal olfactory epithelial toxicity at 50 ppm in parental rats. The NOAEL for maternal and developmental toxicity was 10 ppm based on reduced maternal weight gain and food consumption and reduced fetal weight at 50 ppm in the developmental toxicity study.

Inhalation toxicology of fumed dodecanediamine

Dodecanediamine (DDDA) is used in the production of specialty polymers. Exposure to this chemical was associated with dermal sensitization in pilot-plant workers, and the possibility that the chemical could produce dermal sensitization was confirmed in a guinea pig test. This property and its dermal irritative properties demonstrate the need to limit skin contact. The possibility of exposure via inhalation also exists. Although stable under ambient conditions, DDDA is processed at elevated temperatures where it may fume, forming a carbamate after reaction with atmospheric carbon dioxide. Some of the carbamate may be converted back to the diamine after hydrolysis in tissue. The rat was used to evaluate the effects of both acute and repeated exposure following inhalation. Fumed DDDA was found to be moderately toxic following a single 4-h exposure with lethality seen at concentrations of 680 mg/m3 or higher. Rats were then exposed to concentrations of either 0 (control), 11, 34, or 98 mg fumed DDDA/m3, 6 h/day, 5 days/wk for 2 wk. Mortality was seen at the highest concentrations, along with increased lung weights. In these rats, laryngeal and tracheal lesions consisting of acute necrosis and inflammation were seen, but surviving rats given a 14-day recovery period showed almost complete recovery. Tracheal and laryngeal lesions were not seen in rats exposed to either 11 or 34 mg/m3. Degenerative and necrotizing lesions were seen in the nasal regions, primarily the respiratory mucosa, of rats in all three treatment groups. The lesions were exposure related with regard to incidence and severity, but regeneration was seen following the recovery period. No evidence of systemic toxicity was seen. The dose-response characteristics of the nasal lesions and the sensitization potential suggest that workplace control levels of 0.1 mg/m3 should be sufficient to protect workers against the untoward effects of fumed DDDA.

Microsatellite instability in gastrointestinal tract tumours

Although a number of studies have documented microsatellite instability (MSI) in gastrointestinal tumours, the clinical significance is uncertain. In this study the MSI status and clinicopathological features were examined in gastric and colorectal tumours. Eighty-four gastrointestinal tumours were examined for MSI. Normal and tumour DNA isolated from the same patients were analysed at five different microsatellite loci. Clinical features of these patients were also collated and compared with MSI status. High level MSI (MSI-H) (as defined by instability in 2 or more microsatellites) was detected in 6 out of 47 (13%) colon tumours and 6 of 37 (16%) gastric tumours. The frequency of MSI-H between these groups was not statistically significant (P = 0.36). There was no significant correlation with patient age or gender, UICC stage, or degree of differentiation of the tumour. This was true both when analysed as a group, as well as when divided into colon and gastric sites. Our results confirm that a proportion of sporadic tumours from the colon and stomach exhibit an MSI-H phenotype. However, there was no significant relationship between the presence of MSI and any of the clinicopathological characteristics studied.

Production of polyunsaturated fatty acids by polyketide synthases in both prokaryotes and eukaryotes

Polyunsaturated fatty acids (PUFAs) are essential membrane components in higher eukaryotes and are the precursors of many lipid-derived signaling molecules. Here, pathways for PUFA synthesis are described that do not require desaturation and elongation of saturated fatty acids. These pathways are catalyzed by polyketide synthases (PKSs) that are distinct from previously recognized PKSs in both structure and mechanism. Generation of cis double bonds probably involves position-specific isomerases; such enzymes might be useful in the production of new families of antibiotics. It is likely that PUFA synthesis in cold marine ecosystems is accomplished in part by these PKS enzymes.

In vitro genotoxicity testing of (1-chloroethenyl)oxirane, a metabolite of beta-chloroprene

(1-Chloroethenyl)oxirane (CEO) is a metabolite of beta-chloroprene (2-chloro-1,3-butadiene, CD). The purpose of this study was to evaluate the in vitro mutagenic and clastogenic (chromosome breaking) potential of CEO. For comparative purposes, the study also included an evaluation of the racemic compounds, 3,4-epoxy-1-butene (EB) and 1,2:3,4-diepoxybutane (DEB). Mutagenicity was evaluated in a bacterial reverse mutation test (Ames), using the pre-incubation method in the presence and absence of an exogenous metabolism system (Aroclor)-induced rat liver S9). Four Salmonella typhimurium tester strains, TA97a, TA98, TA100 and TA1535 were used. The exposure concentrations in the sealed incubation vials ranged from 0 to 69 mM for CEO, 0 to 102 mM for EB, and 0 to 83 mM for DEB. All three compounds showed signs of toxicity, with DEB being substantially more toxic than either CEO or EB. Mutagenic activity was observed with all three chemicals in primarily the base pair substitution strains (S. typhimurium TA100 and TA1535), but some activity was also seen in the frameshift elimination strains (S. typhimurium TA97a and TA98). The observed mutagenic responses after exposure with CEO or EB were greater than the observed response for DEB, most likely because of the higher toxicity of DEB. Generally, the mutagenic responses were unchanged in the frameshift strains and base pair substitution strains in the presence of S9 metabolism. In vitro clastogenicity was evaluated using the cytochalasin-B blocked micronucleus test in cultured Chinese hamster V79 cells. The test was conducted without S9 metabolism because of the absence of substantial changes in the Ames test. Exposure concentrations ranged from 0 to 0.943 mM for CEO, 0 to 3.0 mM for EB, and 0 to 0.035 mM for DEB, with the upper exposure concentrations dictated by cytotoxicity. Cytotoxicity, measured as a reduction in the proportion of binucleated cells and altered cell morphology, was observed for CEO at concentrations > or =0.175 mM. Exposure to EB led to a reduced proportion of binucleated cells at concentrations > or =2.0 mM, and cell death was observed after DEB exposure at concentrations > or =0.025 mM. No clastogenicity was observed in the V79 cells when tested up to cytotoxic concentrations of CEO, whereas an elevated frequency of micronuclei was observed after exposure to either EB (> or =1.0 mM) or DEB (> or =0.0125 mM). These results suggest that CEO-induced mutagenicity, but not clastogenicity, may contribute to the observed beta-chloroprene-induced carcinogenicity in the rodent bioassay studies.

Overview of the acute, subchronic, reproductive, developmental and genetic toxicology of beta-chloroprene

beta-Chloroprene (CD), the 2-chloro derivative of 1,3-butadiene, is used for the manufacture of the synthetic rubber, polychloroprene. Acute inhalation studies show that CD is lethal to Crl:CD rats at >2300 p.p.m. (4 h); the primary target organ effects were pulmonary hemorrhage and edema, and hepatic necrosis. In 2- and 4-week inhalation studies in Fischer 344 (F344) and Wistar rats, early deaths occurred at 500 and > or =161 p.p.m., respectively. Organ system injury was found in the nose (degeneration/metaplasia of olfactory epithelium), liver (centrilobular necrosis), and blood (decreased red blood cell count in F344 rats only). In a 90-day inhalation study with F344 rats, degeneration/metaplasia of the olfactory epithelium and reduced nonprotein sulfhydryl content of lungs and liver were found in animals exposed to 80 p.p.m., and anemia, hepatocellular necrosis, and forestomach inflammation were observed at 200 p.p.m. In a 90-day study with B6C3F1 mice, CD caused deaths at 200 p.p.m., the highest concentration tested, and epithelial hyperplasia of the forestomach at 80 p.p.m. Other than a slight (<10%) reduction in sperm motility in male rats at 200 p.p.m., all other reproductive parameters (sperm count or morphology in males, and estrous cyclicity or cycle length in females) were unaffected in these 90-day rat/mouse studies. There were no significant indications of neurological toxicity. The study No-Observable Adverse Effect Level was 32 p.p.m. based on nasal injury in rats. Despite some early reports of reproductive system abnormalities at levels <1 p.p.m., recent studies show no embryotoxic or developmental toxicity in female Wistar or Crl:CD rats, or in New Zealand White rabbits at CD exposure concentrations up to 25 or 175 p.p.m., respectively. In a one-generation reproduction study with Wistar rats, CD produced growth retardation in the F(0) generation exposed to 100 p.p.m., and in the F(1) offspring at 33 and 100 p.p.m.; no effects on reproductive parameters or histopathology were found. CD is nonmutagenic in standard plate incorporation bacterial reverse mutation assays (Ames assays) but positive using direct gas-phase incubation methods. Bacterial mutagenicity (primarily base pair substitution) was either negative or weakly positive when freshly prepared CD was tested. Mutagenicity increased markedly with time, presumably from CD dimer formation, and also by addition of liver S9 metabolic activation system. In vivo micronucleus, chromosome aberration and sister chromatid exchange studies in mice showed no structural chromosomal damage. Overall, the pathological effects in the liver and nose dominate the subchronic toxicity of CD. The genotoxicity of CD is inconsistent and requires further study.

The metabolism of beta-chloroprene: preliminary in-vitro studies using liver microsomes

Based on analogy with butadiene and isoprene, the metabolism of beta-chloroprene (2-chloro-1,3-butadiene, CD) to reactive intermediates is likely to be a key determinant of tumor development in laboratory rodents exposed to CD by inhalation. The purpose of this study is to identify species differences in toxic metabolite (epoxide) formation and detoxification in rodents and humans. The in-vitro metabolism of CD was studied in liver microsomes of B6C3F1 mice, Fischer/344 and Wistar rats, Syrian hamsters, and humans. Microsomal oxidation of CD in the presence of NADP(+), extraction with diethyl ether, and analysis by GC-mass selective detection (MSD) indicated that (1-chloroethenyl)oxirane (CEO) was an important metabolite of CD in the liver microsomal suspensions of all species studied. Other potential water-soluble oxidative metabolites may have been present. The oxidation of CD was inhibited by 4-methyl pyrazole, an inhibitor of CYP 2E1. CEO was sufficiently volatile at 37 degrees C for vial headspace analysis using GC-MSD single ion monitoring (m/z=39). CEO was synthesized and used to conduct partition measurements along with CD and further explore CEO metabolism in liver microsomes and cytosol. The liquid-to-air partition coefficients for CD and CEO in the microsomal suspensions were 0.7 and 58, respectively. Apparent species differences in the uptake of CEO by microsomal hydrolysis were hamster approximately human>rats>mice. Hydrolysis was inhibited by 1,1,1-trichloropropene oxide, a competitive inhibitor of epoxide hydrolase. A preliminary experiment indicated that the uptake of CEO in liver cytosol by GSH conjugation was hamster>rats approximately mice (human cytosol not yet tested). In general, the results suggest that metabolism may help explain species differences showing a greater sensitivity for CD-induced tumorigenicity in mice, for example, compared with hamsters. Additional experiments are in progress to quantify the kinetic parameters of CD oxidation and CEO metabolism by enzymatic hydrolysis and conjugation by glutathione S-transferase for in cytosol. A future goal is to use the kinetic rates to parameterize a physiologically based toxicokinetic model and relate the burden of toxic metabolite to the cancer dose-response observed in experimental animals.

Inhalation toxicity of Dioxole and Dioxolane compounds in the rat

Four chemicals (Dioxole 418, Dioxolane 418, Dioxolane 416 and Dioxolane 456) which are used as stabilizers in highresolution image were tested or both their acute and repeated inhalation toxicity in the rat using nose-only exposures. Acute studies determined the lethal concentrations following a single 4-hour exposure; repeated exposure inhalation studies determined the potency and target tissue(s) following 6-hour/day exposures, 5 days/week for 2 weeks. Each of the chemicals was at least mildly toxic acutely with approximate lethal concentrations of > 1,500 ppm for Dioxole 418, 1,300 ppm for Dioxolane 418, 1,700 ppm for Dioxolane 416, and 4,300 ppm for Dioxolane 456. No specific unusual clinical signs of response were seen in the rats exposed acutely. Repeated exposures with Dioxole 418 and Dioxolane 418 resulted in no evidence of toxicity with NOAEL's being 440 and 500 ppm respectively (the highest concentrations tested). Repeated exposures to 250 ppm Dioxolane 456 were not tolerated with mortalities observed after exposure. Severe bone marrow hypoplasia along with reductions in platelet and neutrophil counts were observed at this concentration with less severe hemopoietic changes seen also at 10 and 51 ppm. The no-effect level for Dioxolane 456 was determined to be 10 ppm in female rats and I ppm in males. The same hemopoietic effects were seen with Dioxolane 416 at exposures of 53 ppm or greater in males but not in females exposed to 53 ppm Dioxolane 416. Hepatocellular hypertrophy and depression of serum alkaline phosphatase activity were seen in male rats exposed to 500 but not 53 ppm Dioxolane 416. Testicular degeneration was also seen in rats exposed to 500 ppm Dioxolane 416. The NOAEL was 5 ppm for the chemical.

Necrotizing pulmonary granulomata in a marijuana smoker

We describe the case of a heavy marijuana and tobacco smoker who presented with progressive exertional dyspnea of 2 months' duration, and bilateral nodular lung infiltrates. Examination of the lung fields was normal, and lung function tests showed mild airflow obstruction with moderately reduced gas transfer. BAL returned green-black fluid consisting predominantly of macrophages laden with carbon pigment. Thoracoscopic lung biopsy showed miliary necrotizing granulomata with an alveolar exudate of carbon-laden macrophages within macroscopically blackened lung. The differential diagnosis of pulmonary granulomata in this patient is discussed.

Subchronic inhalation toxicity of diglyme

Diglyme [1,1'-oxybis(2-methoxyethane)] is an organic solvent belonging to the glycol ether class of compounds. To assess the inhalation toxicity of diglyme, groups of 20 male and 10 female rats were exposed by nose-only inhalation 6 hours/day, 5 days/week for 2 weeks to either 0 (control), 110, 370 or 1100 ppm diglyme. To compare potency, 2-methoxyethanol was also tested at 300 ppm. Rats were sacrificed either immediately following exposure, after a 14-day recovery period, or after 42 and 84 days of recovery (males only). Parameters investigated included in-life observations and body weights, clinical pathology, and histopathology with organ weights. Exposure to diglyme produced a variety of concentration-related haematological, clinical chemical and histopathological changes in both sexes. The most striking effect produced in all test groups was cellular injury involving the testes, seminal vesicles, epididymides and prostate. Although these effects were more severe at the higher concentrations tested, partial or complete recovery was seen by 84 days post-exposure. Changes in the haematopoietic system occurred in both sexes and involved the bone marrow, spleen, thymus, leucocytes and erythrocytes. The testicular effects of diglyme were somewhat less pronounced than those seen with 2-methoxyethanol. The no-observed-effect level (NOEL) for repeated inhalation exposure to diglyme in female rats is 370 ppm. For males, all concentrations tested produced effects to the reproductive system, hence a no-observed-effect level could not be demonstrated.

Developmental toxicity of diglyme by inhalation in the rat

Diglyme (Diethylene glycol dimethyl ether, CAS No. 111-96-6) is a glycol ether which has been used in solvent formulations. To assess the potential developmental toxicity of this chemical, groups of pregnant Crl:CD BR rats were exposed to either 0 (control, room air only), 25, 100, or 400 ppm diglyme by inhalation for 6 hrs/day for Days 7 through 16 or gestation (day on which the copulation plug was detected was designation Day 1 G). All female rats were euthanized on day 21G and the fetuses were examined. An additional group of rats was treated with 25 ppm 2-methoxethanol (2ME) to serve as a positive control and for comparison of relative potencies. Maternal toxicity evident as depressed feed consumption at 400 ppm and increased liver weights at 100 ppm. There were no dams in the 400 ppm group with live fetuses (all litters consisted on resorbed conceptuses). Embryo viability was unaffected by concentrations of diglyme as high as 100 ppm. 2ME produced increased liver weights and depressed feed consumption at 25 ppm. Embryo-fetal toxicity was evident as a concentration-related decrease in fetal weight at diglyme concentrations as high as 100 ppm (and with 2ME). There were no fetuses derived from the 400 ppm diglyme-treated dams. A low incidence of structural malformations was observed in all diglyme groups (as well as with 2ME). The incidence of variations, (primarily delayed skeletal ossification and rudimentary ribs) was increased in the 25 and 100 ppm diglyme groups. The incidence and severity in the diglyme and 2ME groups exposed to 25 ppm was essentially the same suggesting similar potency for producing structural variations. In this study, diglyme was embryolethal at 400 ppm; a level that otherwise was only marginally toxic to the dam. Maternal and fetal toxicity also were demonstrated at 100 ppm. Although the fetal defects detected following diglyme exposure at 25 ppm were not significantly different from control values (with the exception of the incidence of skeletal developmental variations), the pattern, type, and incidence of variations were similar to those seen at 100 ppm, suggesting that 25 ppm was an effect level that approaches the lower end of the developmental toxicity response curve. Therefore, the no-observable-effect level (NOEL) for diglyme exposure in the dam is 25 ppm and a NOEL was not clearly demonstrated for the conceptus.

Frequency and clinico-pathological associations of ras mutations in colorectal cancer in the Victorian population

BACKGROUND

Mutations in the oncogene ras occur in 20-50% of colorectal cancers. The presence of these mutations allows screening tests to be developed based on the identification of mutant DNA in cells derived from cancers. A study of the prevalence and clinicopathological associations of ras mutations was undertaken.

METHODS

The frequency of mutations in codons 12 and 13 of the K-ras gene was investigated in 103 colorectal carcinomas using restriction fragment length polymorphism.

RESULTS

Mutations were detected in 32% (33/103) of the tumours, predominantly in codon 12 (25/33). No mutations were detected in normal-appearing mucosa from the same patients.

CONCLUSIONS

Analysis of the frequency of ras mutations compared with various independent clinical variables revealed a sex-linked relationship between the presence of a ras mutation and nodal status but no correlation with any other clinical parameter was found. The findings suggest that screening tests based on ras mutation detection may lack sensitivity because of the presence of mutations in only 32% of tumours.

Developmental toxicity of inhaled N-methylformamide in the rat

The developmental toxicity of N-methylformamide (MMF), an industrial chemical intermediate used in the production of agrichemicals, was examined in pregnant rats. MMF was administered by nose-only inhalation, 6 hr daily on Days 7-16 of gestation (the day copulation was confirmed was termed Day 1 of gestation, Day 1G) at exposure concentrations of 0, 15, 50, or 150 ppm. Dams were regularly monitored throughout gestation for body weight gain, feed consumption, and clinical signs. Cesarean sections were performed on Day 22G and the offspring were examined. Maternal toxicity was evident in dams exposed to 50 or 150 ppm; one dam exposed to 150 ppm died on Day 14G (considered to be treatment-related) and dams in the 50 and 150 ppm groups exhibited concentration-related clinical findings. Clinical signs of wheezing and rattling were observed both during and after the exposure period. The 150 ppm group also showed significant decreases in weight gain and feed consumption. A significant increase in the mean number of resorptions per litter at the 150 ppm level indicated an embryolethal effect. Developmental toxicity was apparent by a significant decrease in mean fetal body weight and increases in fetal malformations (subcutaneous cysts on the head, microphthalmia, anophthalmia, fused ribs and/or vertebra, and distended brain ventricles) and variations (misaligned and fused sternebrae) due to retarded development at 150 ppm. Significant fetal body weight decreases were also present at 50 ppm. Thus, in this study, the no-observable-adverse-effect level for both dam and fetus was 15 ppm MMF, indicating that for the parameters included in this study, the conceptus is not uniquely sensitive to MMF.

Dimethylacetamide pharmacokinetics following inhalation exposures to rats and mice

Whole-body inhalation exposures to N,N-dimethylacetamide (DMAC) were conducted with male rats (Crl:CD BR) and mice (Crl:CD-1 (ICR)BR). Exposure concentrations were 50, 150, 300 and 500 ppm. The exposure routines consisted of single 1-, 3-, or 6-h exposures and ten 6-h exposures (10 exposure days in 2 weeks). Area under the plasma concentration curve (AUC) values were determined for DMAC and its metabolite N-methylacetamide (NMAC), following 6-h exposures (single exposure or last in a series of 10 exposures). The range of exposures was chosen to assess the exposure-dependent nature of DMAC pharmacokinetics in rats and mice. Plasma profiles indicated mice metabolized DMAC rapidly with plasma half-lives from 0.3 to 0.5 h for DMAC. The DMAC AUC values from mice were underestimated due to the required time (< 30 min) between termination of exposure and the initial blood sample. DMAC plasma half-life in rats ranged from 0.6 to 1.5 h. The AUC values for DMAC in rats increased approximately 5-fold and 3-fold as exposure concentrations increased from 150 to 300 ppm and 300 to 500 ppm, respectively. NMAC persisted in plasma for at least 24 h after the 150, 300 and 500 ppm exposures to rats. NMAC was not detected in plasma from mice beyond the 12-h post-exposure timepoint for the 300 and 500 ppm exposures. Regardless of exposure level, repeated DMAC exposures to both rats and mice resulted in plasma profiles of DMAC and NMAC similar to those from a single exposure. The dose-dependent nature of the DMAC AUC data and the absence of effects of repeated 300 and 500 ppm DMAC exposures supported a toxicity-driven upper limit of 350 ppm for a chronic inhalation study.

Intravascular endometrial tissue in an ovary of a patient with abnormal endometrial histology

A case of ovarian intravascular endometrial tissue in a 46 yr old woman with a strong family history of endometrial carcinoma and abnormal endometrial histology is presented. The diagnosis was supported by histological and immunohistochemical findings. Although recognized at other sites, intravascular endometrial tissue has not been described previously in the ovary.

Testicular degeneration and spermatid retention in young male rats

The incidence of spontaneous testicular atrophy and its morphological changes in relation to stage-specific spermatogenesis were investigated in young Crl:CD/BR male rats at 10-12 wk of age used as controls for toxicity screening during 1983-1990. The incidence of testicular degeneration was 2.5% (5/197) in control rats used for oral toxicity studies and 9.4% (31/327) in rats used for inhalation studies. The epididymal tubules of rats with testicular degeneration had exfoliated germ cells and low sperm density. The high incidence of testicular degeneration observed in the control rats used in inhalation studies may be related to the stress associated with immobilization in the restrainer during nose-only exposure conditions. The severity of testicular degeneration in the inhalation studies was mostly minimal. In these minimally affected testes, mature spermatids (step 19) were retained within normal-appearing germinal epithelium at spermatogenic stages IX-XIV. Also, eosinophilic globular bodies (EGBs) were formed with elongated or mature spermatids throughout all spermatogenic stages, but the general architecture of germinal epithelium was normal in appearance. By electron microscopy, EGBs were sequestered necrotic spermatids, and the germ cell degeneration was associated with cytoplasmic vacuolation of Sertoli cells. In moderate testicular degeneration, markedly decreased maturing spermatids (steps 15-19) and a slight depletion of round spermatids were observed in stages I-VIII. In severe testicular degeneration, seminiferous tubules were lined with 1-2 layers of round spermatids and spermatocytes with giant cell formation. The round spermatids served as a marker to identify spermatogenic stages (I-VIII) of the atrophic tubules. Also, in severe testicular degeneration, tubules in spermatogenic stages X-XIV had no elongated spermatids, and spermatocytes were exfoliated with occasional giant cell formation. Many seminiferous tubules were lined with only 1-2 layers of spermatocytes, and specific germ cell markers were not present.

Developmental toxicity of inhaled trans-1,2-dichloroethylene in the rat

The developmental toxicity of trans-1,2-dichloroethylene (t-DCE), a component of certain Freon cleaning agents, was examined in pregnant rats. t-DCE was administered by inhalation 6 hr daily on Days 7-16 of gestation (the day copulation was confirmed was termed Day 1 of gestation) at exposure levels of 0, 2000, 6000, or 12,000 ppm. The offspring were then examined on Day 22 of gestation. Overt maternal toxicity was expressed as a significant reduction in weight gain at 12,000 ppm and in feed consumption at 6000 and 12,000 ppm. During the exposure period, lacrimation and stained periocular hair, and signs of ocular irritation, were observed in all groups. In addition, increased incidences of alopecia, lethargy, and salivation were observed in the high-dose dams. Significant increases in the mean number of resorptions per litter were seen in the litters of dams exposed to 6000 and 12,000 ppm of t-DCE; however, these values are within the range of historical controls and not considered to be treatment related. The mean combined and female fetal weights were significantly reduced in the litters of dams exposed to the highest concentration (12,000 ppm) of t-DCE. Marginal effects on feed consumption, unaccompanied by other changes and reflective of the pattern seen at higher doses, were seen at 2000 ppm. Thus, marginal maternal toxicity was seen at 2000 ppm and exposures to 6000 ppm t-DCE or higher caused frank maternal toxicity while the fetus was affected only at 12,000 ppm. Therefore, t-DCE is not considered to be uniquely toxic to the rat conceptus.

Dimethylformamide pharmacokinetics following inhalation exposures to rats and mice

Whole-body inhalation exposures to N,N-dimethylformamide (DMF) were conducted with rats and mice. The exposure concentrations were 10, 250, and 500 ppm DMF. The exposure routines consisted of single 1-, 3-, or 6-hour exposures and ten 6-hour exposures (ten exposure days in 2 weeks). Area under the plasma concentration curve (AUC) values were determined following exposure for DMF and "N-methylformamide" ["NMF" represented N-methylformamide plus N-(hydroxymethyl)-N-methylformamide (DMF-OH)]. The DMF AUC values increased 8- and 29-fold for rats and mice, respectively, following single six-hour exposures to 250 and 500 ppm DMF. These data are indicative of saturation of DMF metabolism. Peak "NMF" plasma concentrations for rats and mice, following single 6-hour exposures, did not increase as DMF exposure concentrations increased from 250 to 500 ppm. In addition, the "NMF" plasma levels in rats following a single 6-hour 500 ppm DMF exposure did not decay by 24 hours post exposure. These "NMF" plasma data also indicate saturation of DMF metabolism. Multiple exposures to 500 ppm DMF resulted in a 3- and 4-fold reduction in DMF AUC values for rats and mice, respectively, compared to AUC values following a single six-hour 500 ppm DMF exposure. This indicates enhanced metabolism of DMF resulting from multiple 500 ppm DMF exposures and together with saturation of DMF metabolism suggest using exposure levels below 500 ppm in a chronic bioassay. Selected plasma samples were simultaneously assayed for NMF and DMF-OH. The "NMF" values consisted of between 30 to 60 percent DMF-OH depending upon the exposure group (conversely NMF represented 30 to 60 percent of the "NMF" levels). Urinary analysis of all samples revealed DMF-OH represented over 90 percent of the summed DMF, DMF-OH and NMF quantities.

Nasal lesion development and reversibility in rats exposed to aerosols of dibasic esters

This study was conducted to investigate the initial tissue damage, morphogenesis, and reversibility of nasal lesions induced by the inhalation of dibasic esters (DBE). Young male rats were exposed, nose-only, to an aerosol/vapor mixture of DBE at a concentration of 5,900 mg/m3 for 4 hr and subsequently killed at 1, 4, 7, 14, 21, and 42 days after exposure. Nasal lesions were distributed along major inspiratory airflow routes. Widespread epithelial denudation occurred in the anterior nasal cavity, but the lesions were confined to the dorsal meatus, adjacent the nasal septum, and the lateral middle meatus in the mid-anterior nasal cavity. The lesions were markedly less severe in the posterior nasal cavity and sharply confined to the tips of dorsal ethmoturbinates and adjacent nasal septum. The damaged cuboidal/nonciliated and respiratory epithelium in the anterior nasal cavity regained a normal structure by 4 and 7 days postexposure, respectively. The regeneration of damaged olfactory epithelium was related to the severity of initial tissue damage. Slightly damaged epithelium regained a normal appearance within 1-2 weeks, but the extensively denuded epithelium of the dorsal meatus in the anterior nasal cavity failed to regain a normal structure by 6 weeks. The sustentacular cells of the olfactory epithelium appeared to be the initial site of DBE nasal injury. In the early stages of regeneration, the epithelium was repaired by proliferating stem cells derived from basal cells. Numerous mitotic figures and bromodeoxyuridine labeling were found in the regenerating basal cells, stem cells, and sustentacular cells at 4 and 7 days. As repair processes advanced, the numbers of olfactory neurons and vesicles were increased with a proportional decrease in stem cells.

An open label trial of alprazolam in comorbid irritable bowel syndrome and generalized anxiety disorder

BACKGROUND

The irritable bowel syndrome (IBS) is very prevalent and psychiatric comorbidity runs high. A significant proportion of generalized anxiety disorder (GAD) patients manifest concurrent IBS.

METHOD

We conducted a 14-week, open-label trial of the triazolobenzodiazepine alprazolam in 32 patients with comorbid generalized anxiety and IBS. At the end of a 2-week placebo run-in, eligible subjects received 6 weeks of active drug therapy.

RESULTS

Ninety-four percent of subjects (N = 25) had a full or partial anxiolytic response at the 6th treatment week (p less than .001). Eighty-nine percent (N = 24) experienced a concomitant reduction in IBS severity. For the majority, these dual benefits were still evident at the conclusion of a 4-week drug taper (p = .05) and achieved a trend (p = .07) at a 4-week postdrug discontinuation visit.

CONCLUSION

Alprazolam was safe, effective, and well tolerated during the acute treatment of comorbid GAD and IBS; only a limited posttreatment rebound was observed.

Pathogenesis and reversibility of retinopathy induced by 1,4-bis (4-aminophenoxy)-2-phenylbenzene (2-phenyl-APB-144) in pigmented rats

Pigmented male rats were administered a suspension of 0, 25, or 100 mg/kg 2-phenyl-APB-144 in corn oil by gavage. The rats were killed at 4 and 12 h, and at 1, 2, 4, 7, 14, 28, 57, or 84 days after a single oral administration. The primary site of retinopathy appeared to be the retinal pigment epithelial (RPE) cells. The RPE cells showed necrosis within 12 h post-exposure (PE) at 25 mg/kg and within 4 h PE at 100 mg/kg. Subsequently, photoreceptor outer segments (POS) were disrupted with a hyperplastic RPE cell response within 2 days PE. Intact photoreceptor inner segments (PIS) and RPE cells apposing closely with distal POS were important determinants for reversibility of the damaged POS. The damaged RPE cells were regenerated prior to restoration of normal POS. At 25 mg/kg, both the RPE cells and POS were damaged, but PIS were intact. The damaged POS were regenerated from intact PIS with closely apposing RPE cells. By 14 days PE, the damaged POS had partially regenerated and attained approximately one third to one half of their normal length. By 57 and 84 days PE, the damaged retina had regained an essentially normal structure. In contrast, at 100 mg/kg, the POS and PIS were extensively disrupted, with marked RPE cell hyperplasia after 7 days PE resulting in the formation of multiple retinal arcades (foldings), and rosettes by 14 days PE. Subsequently, retinal arcades and rosettes gradually disappeared as the result of extensive loss of PIS and POS with progressive migration of photoreceptor nuclei toward the Bruch's membrane after 28 days PE. Focal regeneration of POS was observed by 57 days PE where intact PIS and a single layer of regenerated RPE cells were apposed closely with distal POS. The POS regeneration did not occur where the RPE cells were denuded or hyperplastic RPE cells were present. The hyperplastic RPE cells were devoid of slender apical processes, closely enclosing the distal POS. Approximately 20-30% of the retina had partially regained a normal structure by 84 days PE.

Retinotoxicity of 1,4,-bis(4-aminophenoxy)-2-phenylbenzene (2-phenyl-APB-144) in albino and pigmented rats

Albino and pigmented strains of rats were administered 0, 5, 25, 100 or 500 mg/kg 2-phenyl-APB-144 by gavage and were killed 14 days later. Although no ocular lesions were found in rats dosed at 5 mg/kg, similar dose-related retinopathy was found at 25, 100, or 500 mg/kg in both albino and pigmented rats. The primary target site appeared to be retinal pigment epithelial (RPE) cells and photoreceptor outer segments (POS). At 25 mg/kg or greater, multifocal retinal detachment with disrupted POS occurred where the RPE cells showed necrotic changes and contact loss with POS due to fragmentation of apical processes in the RPE cells. Also, RPE cells showed hyperplasia, migration, and phagocytic activity toward disrupted POS. The photoreceptor nuclei (outer nuclear cells) were displaced into the areas occupied by disrupted POS. At 100 or 500 mg/kg, multifocal or diffuse disruption of POS and photoreceptor inner segments (PIS) was observed with markedly proliferating RPE cells. The photoreceptor nuclei were disorganized, less numerous, and necrotic. Some photoreceptor nuclei directly apposed the RPE cells or Bruch's membrane due to the absence of both POS and PIS. The cytoplasm of RPE cells was loaded with phagosomes, disrupted lamellar discs, myelin bodies, and lysosomal residual bodies. The morphological changes appeared to be related to lysosomal dysfunction of the RPE cells. The presence of melanin pigment in the RPE cells did not appear to be the primary factor in the development of the retinopathy.

Comparative testicular toxicity of bis(2-methoxyethyl) ether and 2-methoxyethanol in rats

Male rats were exposed to 0, 110, 370, or 1100 ppm bis(2-methoxyethyl)ether (diglyme) 6 h/day, 5 days/week for 2 weeks. One group of male rats was exposed to 300 ppm 2-methoxyethanol (2-ME) for 2 weeks as a positive control. Exposed rats were killed after 10 days of exposure and 14, 42, or 84 days post-exposure (PE), respectively. At 110 ppm diglyme, spermatocytes in pachytene and meiotic division at spermatogenic stages XII-XIV were mainly affected. At 370 ppm diglyme, affected germ cells were similar to those seen at 110 ppm diglyme, but round spermatids at spermatogenic stages I-VII were also affected. The testes regained normal spermatogenesis by 84 days PE. At 1100 ppm diglyme or 300 ppm 2-ME, marked testicular atrophy was found affecting all spermatogenic stages. Damaged seminiferous tubules were lined with regenerating pachytene spermatocytes at 14 days PE and with spermatocytes and round spermatids after 42 days PE. Most but not all testes in rats exposed to 300 ppm 2-ME or 1100 ppm diglyme had normal morphology after 84 days PE. Based on the observation of germ cell damage, spermatozoa population in the epidymal tubules, reversibility of spermatogenesis after various PE periods, testicular toxicity induced by 300 ppm 2-ME was more severe than that seen at 370 ppm diglyme but was slightly less remarkable than that of 1100 ppm diglyme.

Primary aldosteronism due to a malignant ovarian tumour

The case of a woman with autonomous aldosteronism, hypertension, and malignant ovarian tumour is reported. Hormone studies revealed high plasma aldosterone levels, and low plasma renin concentration. Following surgical removal of a malignant sex cord stromal tumour, the hyperaldosteronism regressed, and the hypertension improved. Subsequently the tumour recurred, as did hyperaldosteronism.

Thyroxine binding and TSH in recurrent depressive episodes

Evidence of a link between recurrent affective disorders and the hypothalamic-pituitary-thyroid (HPT) axis has been frequently reported. The clinical course of 40 recurrent major depressive patients was monitored over 2 years with respect to several parameters of thyroid function. Patients entering a depressive recurrence manifested lower free versus bound thyroxine quotients and had higher TSH secretion. A dynamic HPT axis response may enhance the clinical outcome of acute depression during continuation pharmacotherapy.

A rare pelvic mass: osteosarcoma of the body of the uterus

A rare, enormous, unresectable, osteosarcoma of the uterus is reported. This obstructed ureters, enclosed rectum, bladder, aorta and vena cava, and metastasized to peritoneum, lungs and liver causing death of the patient by renal and pulmonary failure.

Imipramine metabolism in recurrent depressive episodes

The long-term maintenance of major affective disorders with tricyclic antidepressants is of obvious interest. However, discrete predictors identifying subgroups 'at-risk' for higher recurrence rates have infrequently been cited. The clinical course of 32 major recurrent depressive patients was monitored over 2 years. Analysis of the total tricyclic concentration and the parent: desmethylated ratio revealed that those subjects in a depressive recurrence previously had had a lower imipramine: desipramine ratio (despite matched dosing and nonsignificant total plasma concentrations) than nonrecurrents. Several hypotheses are discussed.