Time to Recover From Daily Caffeine Intake

Caffeine elicits widespread effects in the central nervous system and is the most frequently consumed psychostimulant worldwide. First evidence indicates that, during daily intake, the elimination of caffeine may slow down, and the primary metabolite, paraxanthine, may accumulate. The neural impact of such adaptions is virtually unexplored. In this report, we leveraged the data of a laboratory study with N = 20 participants and three within-subject conditions: caffeine (150 mg caffeine × 3/day × 10 days), placebo (150 mg mannitol × 3/day × 10 days), and acute caffeine deprivation (caffeine × 9 days, afterward placebo × 1 day). On day 10, we determined the course of salivary caffeine and paraxanthine using liquid chromatography-mass spectrometry coupled with tandem mass spectrometry. We assessed gray matter (GM) intensity and cerebral blood flow (CBF) after acute caffeine deprivation as compared to changes in the caffeine condition from our previous report. The results indicated that levels of paraxanthine and caffeine remained high and were carried overnight during daily intake, and that the levels of paraxanthine remained elevated after 24 h of caffeine deprivation compared to placebo. After 36 h of caffeine deprivation, the previously reported caffeine-induced GM reduction was partially mitigated, while CBF was elevated compared to placebo. Our findings unveil that conventional daily caffeine intake does not provide sufficient time to clear up psychoactive compounds and restore cerebral responses, even after 36 h of abstinence. They also suggest investigating the consequences of a paraxanthine accumulation during daily caffeine intake.

Probability of pharmacological target attainment with flucloxacillin in Staphylococcus aureus bloodstream infection: a prospective cohort study of unbound plasma and individual MICs

Objectives

MSSA bloodstream infections (BSIs) are associated with considerable mortality. Data regarding therapeutic drug monitoring (TDM) and pharmacological target attainment of the β-lactam flucloxacillin are scarce.

Patients and methods

We determined the achievement of pharmacokinetic/pharmacodynamic targets and its association with clinical outcome and potential toxicity in a prospective cohort of 50 patients with MSSA-BSI. Strain-specific MICs and unbound plasma flucloxacillin concentrations (at five different timepoints) were determined by broth microdilution and HPLC–MS, respectively.

Results

In our study population, 48% were critically ill and the 30 day mortality rate was 16%. The median flucloxacillin MIC was 0.125 mg/L. The median unbound trough concentration was 1.7 (IQR 0.4–9.3), 1.9 (IQR 0.4–6.2) and 1.0 (IQR 0.6–3.4) mg/L on study day 1, 3 and 7, respectively. Optimal (100% fT_>MIC) and maximum (100% fT_>4×MIC) target attainment was achieved in 45 (90%) and 34 (68%) patients, respectively, throughout the study period. Conversely, when using the EUCAST epidemiological cut-off value instead of strain-specific MICs, target attainment was achieved in only 13 (26%) patients. The mean unbound flucloxacillin trough concentration per patient was associated with neurotoxicity (OR 1.12 per 1 mg/L increase, P = 0.02) and significantly higher in deceased patients (median 14.8 versus 1.7 mg/L, P = 0.01).

Conclusions

Flucloxacillin pharmacological target attainment in MSSA-BSI patients is frequently achieved when unbound flucloxacillin concentrations and strain-specific MICs are considered. However, currently recommended dosing regimens may expose patients to excessive flucloxacillin concentrations, potentially resulting in drug-related organ damage.

Regular Caffeine Intake Delays REM Sleep Promotion and Attenuates Sleep Quality in Healthy Men

Acute caffeine intake can attenuate homeostatic sleep pressure and worsen sleep quality. Caffeine intake—particularly in high doses and close to bedtime—may also affect circadian-regulated rapid eye movement (REM) sleep promotion, an important determinant of subjective sleep quality. However, it is not known whether such changes persist under chronic caffeine consumption during daytime. Twenty male caffeine consumers (26.4 ± 4 years old, habitual caffeine intake 478.1 ± 102.8 mg/day) participated in a double-blind crossover study. Each volunteer completed a caffeine (3 × 150 mg caffeine daily for 10 days), a withdrawal (3 × 150 mg caffeine for 8 days then placebo), and a placebo condition. After 10 days of controlled intake and a fixed sleep-wake cycle, we recorded electroencephalography for 8 h starting 5 h after habitual bedtime (i.e., start on average at 04:22 h which is around the peak of circadian REM sleep promotion). A 60-min evening nap preceded each sleep episode and reduced high sleep pressure levels. While total sleep time and sleep architecture did not significantly differ between the three conditions, REM sleep latency was longer after daily caffeine intake compared with both placebo and withdrawal. Moreover, the accumulation of REM sleep proportion was delayed, and volunteers reported more difficulties with awakening after sleep and feeling more tired upon wake-up in the caffeine condition compared with placebo. Our data indicate that besides acute intake, also regular daytime caffeine intake affects REM sleep regulation in men, such that it delays circadian REM sleep promotion when compared with placebo. Moreover, the observed caffeine-induced deterioration in the quality of awakening may suggest a potential motive to reinstate caffeine intake after sleep.

Insufficient Stability of Clavulanic Acid in Widely Used Child-Appropriate Formulations

Amoxicillin-clavulanic acid (AMC) belongs to the WHO Essential Medicines List for children, but for optimal antimicrobial effectiveness, reconstituted dry powder suspensions need to be stored in a refrigerated environment. Many patients in low- and middle-income countries who are sold AMC suspensions would be expected not to keep to the specified storage conditions. We aimed to assess the stability of both ingredients in liquid formulations and dispersible tablets, combined with nationally representative data on access to appropriate storage. Degradation of amoxicillin (AMX) and clavulanic-acid (CLA) was measured in suspensions and dispersible tablets commercially available in Switzerland at different ambient temperatures (8 °C vs. 28 °C over 7 days, and 23 °C vs. 28 °C over 24 h, respectively). Data on access to refrigeration and electricity were assessed from the USAID-funded Demographic and Health Survey program. In suspensions, CLA degraded to a maximum of 12.9% (95% CI -55.7%, +29.9%) at 8°C and 72.3% (95% CI -82.8%, -61.8%) at a 28 °C ambient temperature during an observation period of 7 days. Dispersible tablets were observed during 24 h and CLA degraded to 15.4% (95% CI -51.9%, +21.2%) at 23 °C and 21.7% (-28.2%, -15.1%) at a 28 °C ambient temperature. There is relevant degradation of CLA in suspensions during a 7-day course. To overcome the stability challenges for all active components, durable child-appropriate formulations are needed. Until then, prescribers of AMC suspensions or pharmacists who sell the drug need to create awareness for the importance of proper storage conditions regarding effectiveness of both antibiotics and this recommendation should be reflected in the WHO Essential Medicines List for children.

LC-MS/MS method for nine different antibiotics

BACKGROUND AND AIMS

TDM of antibiotics can bring benefits to patients and healthcare systems by providing better treatment and saving healthcare resources. We aimed to develop a multi-analyte method for several diverse antibiotics using LC-MS/MS.

MATERIALS AND METHODS

Sample preparation consisted of protein precipitation with methanol, dilution and online extraction using a Turboflow Cyclone column. Separation was performed on a Synergi 4 µm Max RP column and deuterated forms of three antibiotics were used as internal standards.

RESULTS

We present a LC-MS/MS method for the quantitative determination of nine antibiotics, including five cephalosporins, the carbapenem ertapenem, the fluoroquinolone ciprofloxacin as well as the combination drug trimethoprim-sulfamethoxazole from plasma. Additionally, unbound ertapenem and cefazolin were analyzed in plasma water after ultrafiltration using plasma calibrators. Results from routine TDM show the applicability of the method.

CONCLUSION

The presented method is precise and accurate and was introduced in a university hospital, permitting fast TDM of all nine analytes. It was also used in a clinical study for measuring cefazolin free and total concentrations.

Caffeine-dependent changes of sleep-wake regulation: Evidence for adaptation after repeated intake

BACKGROUND

Circadian and sleep-homeostatic mechanisms regulate timing and quality of wakefulness. To enhance wakefulness, daily consumption of caffeine in the morning and afternoon is highly common. However, the effects of such a regular intake pattern on circadian sleep-wake regulation are unknown. Thus, we investigated if daily daytime caffeine intake and caffeine withdrawal affect circadian rhythms and wake-promotion in habitual consumers.

METHODS

Twenty male young volunteers participated in a randomised, double-blind, within-subject study with three conditions: i) caffeine (150 mg 3 x daily for 10 days), ii) placebo (3 x daily for 10 days) and iii) withdrawal (150 mg caffeine 3 x daily for eight days, followed by a switch to placebo for two days). Starting on day nine of treatment, salivary melatonin and cortisol, evening nap sleep as well as sleepiness and vigilance performance throughout day and night were quantified during 43 h in an in-laboratory, light and posture-controlled protocol.

RESULTS

Neither the time course of melatonin (i.e. onset, amplitude or area under the curve) nor the time course of cortisol was significantly affected by caffeine or withdrawal. During withdrawal, however, volunteers reported increased sleepiness, showed more attentional lapses as well as polysomnography-derived markers of elevated sleep propensity in the late evening compared to both the placebo and caffeine condition.

CONCLUSIONS

The typical pattern of caffeine intake with consumption in both the morning and afternoon hours may not necessarily result in a circadian phase shift in the evening nor lead to clear-cut benefits in alertness. The time-of-day independent effects of caffeine withdrawal on evening nap sleep, sleepiness and performance suggest an adaptation to the substance, presumably in the homeostatic aspect of sleep-wake regulation.

A 2D HPLC-MS/MS method for several antibiotics in blood plasma, plasma water, and diverse tissue samples

An analytical method using 2D high-performance liquid chromatography followed by tandem mass spectrometry for the quantification of the beta-lactam antibiotics amoxicillin, flucloxacillin, piperacillin, benzylpenicillin, the beta-lactamase inhibitors clavulanic acid, and tazobactam, as well as the macrolide antibiotic clindamycin, is presented. All analytes were measured in human plasma, while amoxicillin, clavulanic acid, flucloxacillin, and clindamycin were also analyzed in human tissue samples. Because of its high-protein binding, additionally, the free fraction of flucloxacillin was measured after ultrafiltration. As internal standards, deuterated forms of the beta-lactams were used. Sample preparation for all matrices was protein precipitation followed by online extraction on a TurboFlow MAX column, while sample separation was performed on an Accucore XL C18 column. Calibration curves were linear over 0.2-25 mg/kg for the tissue samples and 0.05-20 mg/l for the free fraction of flucloxacillin. In plasma, the calibration curves for amoxicillin and piperacillin were linear over 3.125-125 mg/l, for clavulanic acid and tazobactam over 1-40 mg/l, for benzylpenicillin 0.25-40 mg/l, and for flucloxacillin and clindamycin over 1.5-60 mg/l and 0.05-8 mg/l respectively. In plasma and plasma ultrafiltrate, inaccuracy and imprecision for any analyte were always less than 15%. In tissue, the accuracy and precision varied up to 16%, respectively, 20%, when various tissues were analyzed using a calibration in water. Graphical abstract.

Danger of Herbal Tea: A Case of Acute Cholestatic Hepatitis Due to Artemisia annua Tea

Background:Artemisia annua is a Chinese medicinal herb. Artemisinin-derivatives are recommended as part of a combination treatment for uncomplicated malaria. Herbal and dietary supplements (HDS) are increasingly used worldwide and HDS-induced liver injury is becoming a growing concern.

Case Report: We present the first case of severe acute cholestatic hepatitis due to the intake of Artemisia annua tea as chemoprophylaxis for malaria in a patient returning from Ethiopia. The patients presented with jaundice, elevated transaminases, and parameters of cholestasis (total bilirubin 186.6 μmol/L, conjugated bilirubin 168.5 μmol/L). A liver biopsy showed a portal hepatitis with lymphocytic infiltration of the bile ducts and diffuse intra-canalicular and intra-cytoplasmic bilirubinostasis. The toxicologic analysis of the Artemisia tea revealed the ingredients arteannuin b, deoxyartemisin, campher, and scopoletin. There were no other identifiable etiologies of liver disease. The Roussel Uclaf Causality Assessment Method (RUCAM) score assessed a “probably” causal relationship. Sequencing of genes encoding for hepatic transporters for bile acid homeostasis (BSEP, MDR3, and FIC1) found no genetic variants typically associated with hereditary cholestasis syndromes. Normalization of bilirubin occurred 3 months after the onset of disease.

Conclusion: The use of artemisinin-derivatives for malaria prevention is ineffective and potentially harmful and should thus be discouraged. Moreover, the case demonstrates our as yet inadequate understanding of the pathophysiology and susceptibility to HDS induced liver injury.

The non-specific lipid transfer protein, Ara h 9, is an important allergen in peanut

BACKGROUND

Plant food allergy in the Mediterranean area is mainly caused by non-specific lipid transfer proteins (nsLTP). The aim of this study was to characterize peanut nsLTP in comparison with peach nsLTP, Pru p 3, and assess its importance in peanut allergy.

METHODS

Peanut-allergic patients from Spain (n=32) were included on the basis of a positive case history and either a positive skin prick test or specific IgE to peanut. For comparison, sera of 41 peanut-allergic subjects from outside the Mediterranean area were used. Natural Ara h 9 and two isoforms of recombinant Ara h 9, expressed in Pichia pastoris, were purified using a two-step chromatographic procedure. Allergen characterization was carried out by N-terminal sequencing, circular dichroism (CD) spectroscopy, immunoblotting, IgE inhibition tests and basophil histamine release assays.

RESULTS

Compared with natural peanut nsLTP, the recombinant proteins could be purified in high amounts from yeast supernatant (> or =45 mg/L). The identity of the proteins was verified by N-terminal amino acid sequencing and with rabbit nsLTP-specific antibodies. CD spectroscopy revealed similar secondary structures for all preparations and Pru p 3. The Ara h 9 isoforms showed 62-68% amino acid sequence identity with Pru p 3. IgE antibody reactivity to rAra h 9 was present in 29/32 Spanish and 6/41 non-Mediterranean subjects. Recombinant Ara h 9 showed strong cross-reactivity to nPru p 3 and similar IgE-binding capacity as nAra h 9. The two Ara h 9 isoforms displayed similar IgE reactivity. In peanut-allergic patients with concomitant peach allergy, Ara h 9 showed a weaker allergenic potency than Pru p 3 in histamine release assays.

CONCLUSIONS

Ara h 9 is a major allergen in peanut-allergic patients from the Mediterranean area. Ara h 9 is capable of inducing histamine release from basophils, but to a lesser extent than Pru p 3.

[Intermediate-term results after arthroscopic subacromial decompression with special reference to ongoing disability claims]

The objective was to evaluate mid-term results after arthroscopic subacromial decompression (ASD) with special focus on the bias due to an application to social insurance for pension based on sickness disability. The study group consisted of 42 patients (28 male, 14 female). ASD was performed in 1993 or 1994 for impingement stage II. The mean age was 49.5 years. Thirty-nine patients (93%) were evaluated by an independent observer for an average follow-up of 3.5 years (range 1.5-5). Patients satisfaction with the outcome was assessed by a visual analog scale graded from 0 (extremely dissatisfied) to 10 (extremely satisfied). The functional result was assessed using the Constant score. At follow-up the mean VAS value was 6.4 +/- 3.4. The Constant score improved from 49.6 +/- 18.5 to 84.8 +/- 14.3. The subgroup of patients having applied to social insurance for pension had significantly worse results compared with the remaining patients: VAS: 4.9 +/- 3.1 vs. 7.5 +/- 3.1; Constant-Score: 76.1 +/- 12.7 vs. 88.3 +/- 13.5. The fact that patients try to get benefit from social insurance based on sickness disability significantly biased the outcome after ASD.

Spontaneous testicular lesions in purpose-bred beagle dogs

Spontaneous testicular lesions were assessed in 50 control purpose-bred male beagle dogs. They were selected from 13 toxicology studies conducted over the period 1988-1999. Age of the dogs at study termination varied from 8-20 months with an average age of 13 months. Regardless of age, the most significant finding was bilateral segmental hypospermatogenesis in 15/50 (30%) of the dogs. Cross sections of tubules with hypospermatogenesis were distributed randomly throughout the testes and were characterized by reduced proportions of germ cells, tubular shrinkage, and Sertoli cell prominence. These changes were occasionally associated with giant cells, with cellular debris, and in 6/15 (40%) with atrophic tubules devoid of germ cells, indicating a degenerative process. Focal subcapsular tubular atrophy or hypoplasia (tubules lined by Sertoli cells only) was also found in 9/35 (26%) of dogs without hypospermatogenesis. Inhibited spermiation with retention of mature sperm in tubules was seen in 6/50 dogs, 3 of which also showed hypospermatogenesis. Other findings of high incidence but low prevalence included tubules with multinucleated giant cells, swollen spermatocytes, or apoptotic germ cells. These latter changes are probably a constituent of normal spermatogenesis. In conclusion, about 30% of control beagle dogs show segmental hypospermatogenesis, which may be associated with degenerative changes, and an additional 18% of the dogs exhibit focal tubular atrophy/hypoplasia in otherwise normal testes. These changes have to be distinguished from compound-related toxic effects.

Preclinical development of keliximab, a Primatized anti-CD4 monoclonal antibody, in human CD4 transgenic mice: characterization of the model and safety studies

The preclinical safety assessment of biopharmaceuticals necessitates that studies be conducted in species in which the products are pharmacologically active. Monoclonal antibodies are a promising class of biopharmaceuticals for many disease indications; however, by design, these agents tend to have limited species cross-reactivity and tend to only be active in primates. Keliximab is a human-cynomolgus monkey chimeric (Primatized) monoclonal antibody with specificity for human and chimpanzee CD4. In order to conduct a comprehensive preclinical safety assessment of this antibody to support chronic treatment of rheumatoid arthritis in patients, a human CD4 transgenic mouse was used for chronic and reproductive toxicity studies and for genotoxic studies. In addition, immunotoxicity studies were conducted in these mice with Candida albicans, Pneumocystis carinii and B16 melanoma cells to assess the effects of keliximab on host resistance to infection and immunosurveillance to neoplasia. The results of these studies found keliximab to be well tolerated with the only effects observed being related to its pharmacologic activity on CD4+ T lymphocytes. The use of transgenic mice expressing human proteins provides a useful alternative to studies in chimpanzees with biopharmaceutical agents having limited species cross-reactivity.

Repeated cadmium exposures enhance the malignant progression of ensuing tumors in rats

Prior studies show that a single subcutaneous (sc) exposure to cadmium (Cd) will induce injection site sarcomas (ISS) in rats. These tumors, thought clearly malignant, do not often metastasize or invade subdermal muscle layers because of their location. Recent evidence indicates that when tumorigenic cells chronically exposed to Cd in vitro are inoculated into mice, tumor progression and invasiveness in the mice are enhanced. Thus, we studied the effects of repeated Cd exposures on tumor incidence, progression, and metastatic potential in rats. Wistar (WF) and Fischer (F344) rats (30 per group) were injected sc in the dorsal thoracic midline with CdCl2 once weekly for 18 weeks with doses of 0, 10, 20, or 30 micromol Cd/kg. This resulted in total doses of 0, 180, 360, or 540 micromol/kg. One other group of each strain received a low, loading dose of Cd (3 micromol/kg) prior to 17 weekly injections of 30 micromol/kg (total dose 513 micromol/kg). Rats were observed for 2 years. Many F344 rats (57%) died within one week after the first injection of the highest dose, but WF rats were not affected. The low loading dose prevented acute lethality of the high dose in F344 rats. Surprisingly, latency (time to death by tumor) of ISS was the shortest in the groups given the low loading dose in both strains. ISS in these groups also showed the highest rate of metastasis and subdermal muscle layer invasion. Based on ISS incidence in the groups given the lowest total dose of Cd (180 micromoles/kg), F344 rats were more sensitive to tumor induction, showing an incidence of 37% compared to 3% in WF rats. On the other hand, Cd-induced ISS showed a higher overall metastatic rate in WF rats (18 metastatic ISS/68 total tumors in all treated groups; 27%) compared to F344 rats (6%). Immunohistochemically, the primary ISS showed high levels of metallothionein (MT), a cadmium-binding protein, while metastases were essentially devoid of MT. These results indicate that repeated Cd exposures more rapidly induce ISS. An initial low exposure to Cd further accelerates the appearance and enhances the metastatic potential and invasiveness of these tumors. The primary and metastatic ISS appear to have a differing phenotype, at least with regard to MT production. The association between multiple Cd exposures and enhanced metastatic potential of the ensuing tumors may have important implications in chronic exposures to Cd, or in cases of co-exposure of Cd with organic carcinogens, as in tobacco smoking.

The mammary pathology of genetically engineered mice: the consensus report and recommendations from the Annapolis meeting

NIH sponsored a meeting of medical and veterinary pathologists with mammary gland expertise in Annapolis in March 1999. Rapid development of mouse mammary models has accentuated the need for definitions of the mammary lesions in genetically engineered mice (GEM) and to assess their usefulness as models of human breast disease. The panel of nine pathologists independently reviewed material representing over 90% of the published systems. The GEM tumors were found to have: (1) phenotypes similar to those of non-GEM; (2) signature phenotypes specific to the transgene; and (3) some morphological similarities to the human disease. The current mouse mammary and human breast tumor classifications describe the majority of GEM lesions but unique morphologic lesions are found in many GEM. Since little information is available on the natural history of GEM lesions, a simple morphologic nomenclature is proposed that allows direct comparisons between models. Future progress requires rigorous application of guidelines covering pathologic examination of the mammary gland and the whole animal. Since the phenotype of the lesions is an essential component of their molecular pathology, funding agencies should adopt policies ensuring careful morphological evaluation of any funded research involving animal models. A pathologist should be part of each research team.

Idoxifene: a novel selective estrogen receptor modulator prevents bone loss and lowers cholesterol levels in ovariectomized rats and decreases uterine weight in intact rats

Idoxifene, a novel selective estrogen receptor modulator, was tested for its effects on bone loss, serum cholesterol, and uterine wet weight and histology in the ovariectomized (Ovx) rat. Idoxifene (0.5 mg/kg x day) completely prevented loss of both lumbar and proximal tibial bone mineral density (BMD). In an intervention study, idoxifene (0.5 and 2.5 mg/kg x day) completely prevented further loss of both lumbar and proximal tibial BMD during a 2-month treatment period commencing 1 month after surgery, when significant loss of BMD had occurred in the Ovx control group. Idoxifene reduced total serum cholesterol, which was maximal at 0.5 mg/kg x day. Idoxifene alone displayed minimal uterotrophic activity in Ovx rats and inhibited the agonist activity of estrogen in intact rats. Histologically, myometrial and endometrial atrophy were observed in both idoxifene and vehicle-treated Ovx rats. In this report, we also provide molecular-based evidence to support the observations in vivo of a novel selective estrogen receptor modulator (SERM) mechanism of action in bone and endometrial cells. Idoxifene is an agonist through the estrogen response element (ERE) and exhibits similar postreceptor effects to estrogen in bone-forming osteoblasts. Idoxifene also stimulates osteoclast apoptosis, and these pleiotropic effects ultimately could contribute to the maintenance of bone homeostasis. However, idoxifene differs from estrogen in a tissue-specific manner. In human endometrial cells, where estrogen is a potent agonist through the ERE, idoxifene has negligible agonist activity. Moreover, idoxifene was able to block estrogen induced gene expression in endometrial cells, which is in agreement with the observation in the intact rat study. In the uterus, idoxifene has a pharmacologically favorable profile, lacking agonist and therefore growth-promoting activity. Together with its cholesterol lowering effect and lack of uterotrophic activity, these data suggest that idoxifene may be effective in the prevention of osteoporosis and other postmenopausal diseases without producing unwanted estrogenic effects on the endometrium.

Altered hemostasis in male rats following administration of the ACAT inhibitor SKF-99085

SKF-99085, an acyl-CoA:cholesterol acyltransferase (ACAT) was evaluated in male and female Sprague-Dawley rats at oral doses of 0, 10, 100, or 400 mg/kg/day for 6 months as part of the preclinical safety assessment of this drug candidate. In male rats given 400 mg/kg/day SKF-99085, hemorrhage and death were observed in males during the first month of the study, prompting collection of blood samples at weeks 6, 17, and 24 to monitor coagulation parameters. A dose-related increase in activated partial thromboplastin time (APTT) and Thrombotest clotting time (TCT) was observed in all male drug-treated groups. Mean APTT values for male rats given 10, 100, or 400 mg/kg/day were increased maximally to 17.5, 20.8, and 34.7 s (control, 15.4-16.0 s), and mean TCT values were increased to 86, 100, and >300 s (control, 71-74 s), respectively. Mean prothrombin times (PT) for male rats given 400 mg/kg/day were increased to 16.5 s (control, 12.9-13.1 s). Activities of factors II, VII, IX, and X were decreased in males at dosages of 10, 100, or 400 mg/kg/day. Factor V and VIII activities were unaffected. In summary, the drug-related hemorrhagic disorder observed in male rats given high doses of the ACAT inhibitor SKF 99085 was attributed to a reduction in the activity of vitamin-K-dependent coagulation factors. In contrast to humans and some other species, the APTT and TCT were more sensitive than the PT in detecting this effect.

Lack of carcinogenicity of cadmium chloride in female Syrian hamsters

Cadmium is very effective at inducing necrosis within the ovaries of rodents, and the Syrian hamster appears particularly sensitive. The extent of cadmium-induced necrosis depends on the stage of the estrous cycle and is most pronounced when injected on the day prior to ovulation (proestrous). In male rodents cadmium induces a similar necrosis within the testes, which given sufficient time can lead to the development of testicular tumors. In this study we tested the hypothesis that cadmium-induced ovarian necrosis could eventually lead to tumor formation. In sexually mature groups of female Syrian hamsters (> 8 weeks old; n = 50-59), the estrous cycle was determined by visual inspection of vaginal discharge for four consecutive cycles. The animals were then given cadmium (0, 30, 40 and 50 micromol/kg) subcutaneously as a single injection in the dorsal thoracic midline on cycle day 4 (proestrous). Based on prior work, these doses are sufficient to induce extensive acute ovarian damage. Animals were then observed over the next 78 weeks. Although survival and body weight were reduced by cadmium, treatment with the metal did not result in an enhanced incidence of tumors at any site including the ovaries. Non-neoplastic lesions such as amyloidosis and pancreatic hepatocytes were linked to cadmium exposure. These results indicate that the association of cadmium-induced testicular necrosis with tumor development seen in males does not occur in the Syrian hamster ovaries.

An evaluation of the novel selective estrogen receptor modulator, idoxifene, for effects on reproduction in rats and rabbits

Idoxifene, a tissue-specific selective estrogen receptor modulator, was evaluated in male and female rats and female rabbits after oral administration for effects on fertility and/or embryo-fetal development. In all studies, adult toxicity was evident at doses >/=0.03 mg/kg/day in rats and >/=0.1 mg/kg/day in rabbits as evidenced by decreased body weight and/or food consumption. In the male fertility study, rats were treated with 0.003, 0.3, or 3.0 mg/kg/day for 64 to 68 days. Doses >/=0.3 mg/kg/day decreased seminal vesicle and prostate weights and impaired posttesticular sperm development, resulting in decreased epididymal sperm count and weight, but did not affect male fertility. In the female fertility study, rats were treated for 2 weeks prior to mating until insemination with 0.003, 0.03, or 3.0 mg/kg/day. Disrupted estrous cycles, impaired fertility, increased preimplantation loss, and increased vaginal fluid at necropsy were evident at >/=0.03 mg/kg/day. In the early embryonic development study, pregnant female rats were treated from days 0 to 6 postcoitus (pc) with 0.003, 0.03, or 3.0 mg/kg/day idoxifene. Partial or complete preimplantation loss was seen at 0.03 and 3.0 mg/kg/day, respectively. In the embryo-fetal development study, pregnant rats were treated from days 6 to 17 pc with 0.003, 0.03, or 3.0 mg/kg/day. At 3.0 mg/kg/day there was maternal lethality, excess vaginal fluid, embryo-fetal death, generalized fetal edema, and developmental delays. Excess vaginal fluid but no fetal effects were seen at 0.03 mg/kg/day. There were no treatment-related effects at 0.003 mg/kg/day in any rat reproduction study performed. In the rabbit embryo-fetal development study, pregnant New Zealand White rabbits were treated from days 6 to 20 pc with 0.01, 0.1, or 1.0 mg/kg/day idoxifene. At 1.0 mg/kg/day there was maternal lethality, vaginal or uterine bleeding, abortion/premature deliveries, and embryolethality. Vaginal or uterine bleeding was seen at 0.1 mg/kg/day. No treatment-related effects were observed at 0.01 mg/kg/day. Although systemic toxicity was evident in all the studies, the effects of idoxifene on rat and rabbit reproduction were considered to be due to the pharmacological activity of the compound.

The effects of continuous testosterone exposure on spontaneous and cadmium-induced tumors in the male Fischer (F344/NCr) rat: loss of testicular response

In the rodent testes, cadmium induces severe necrosis followed by chronic degeneration. Cadmium is also an effective testicular tumorigen, and a single dose produces a high incidence of Leydig cell tumors. The mechanism of tumor formation is unknown, but pituitary feedback, i.e., increased luteinizing hormone (LH) production due to low circulating androgen, has been implicated in causation of proliferative lesions within degenerate, hypofunctioning testes. Thus, the effects of androgen replacement on the testicular toxicity of cadmium in Fischer (F344/NCr) rats was studied. Groups (n = 50) of 10-week-old rats either received testosterone implants that approximate normal circulating levels in castrated rats or were left untreated. After 2 weeks of stabilization, rats were given either 20 micromol CdCl2/kg, s.c., weekly for the next 5 weeks (total dose 100 micromol/kg) or saline for a total of four treatment groups (control, testosterone alone, testosterone + cadmium, or cadmium alone). Portions of each group were killed either 10 weeks after initiation of cadmium exposure (n = 10), for assessment of endocrine function, or over the next 2 years (n = 40), for assessment of testicular neoplastic lesions. At 10 weeks, cadmium reduced circulating testosterone in nonimplanted rats by nearly 80% and induced a marked weight loss of the testes (>70%) and sex accessory glands (reflected in a 50% reduction in prostate mass). Testosterone implantation restored circulating testosterone levels in cadmium-treated rats and prevented Cd-induced weight loss of the sex accessory glands but not of the testes. Over 2 years, cadmium alone induced a >84% incidence of Leydig cell neoplasia and a >97% incidence of chronic degeneration, both significant increases over control rates (60 and 0%, respectively). Testosterone implantation abolished both cadmium-induced and spontaneously occurring Leydig cell tumors but had no effect on cadmium-induced chronic testicular degeneration. Thus cadmium-induced hypofunction of the testes, and subsequent loss of circulating testosterone, appears to be a critical aspect in cadmium induction of tumors in the rat testes.

Allelotypic and cytogenetic characterization of chemically induced mouse mammary tumors: high frequency of chromosome 4 loss of heterozygosity at advanced stages of progression

Loss of heterozygosity (LOH) is one of the most common genetic abnormalities in cancer. To define the role of LOH and chromosomal abnormalities at various stages of mouse mammary cancer progression, we analyzed the allelotypes and karyotypes of primary mammary tumors induced in CD2F, mice by two basic protocols, the classical multiple-dose 7,12-dimethylbenz[a]anthracene (DMBA) protocol and a novel protocol of combined medroxyprogesterone acetate (MPA) and DMBA. The advantage of the latter protocol is that its latency for tumor development is much shorter and its tumor incidence is higher than those of DMBA alone. To study more advanced stages of mammary tumor progression, we also analyzed mouse mammary tumors that had acquired autonomous growth and were transplantable into syngeneic hosts. The allelotypic studies were performed by means of microsatellite length polymorphism analysis with a minimum of two simple-sequence repeat markers per chromosome. We observed that MPA-DMBA-induced mammary adenocarcinomas, which in general arose earlier because of the growth promotion exerted by MPA, did not show any significant LOH and were essentially diploid. Tumors induced by DMBA alone, which on average took longer to develop, showed a higher frequency of allelic losses. LOH on chromosome 11 was observed in 30% of the cases. Chromosomes 4 and 8 were affected in 25% and 20% of the tumors, respectively. Interestingly, advanced stages of mammary tumor progression, represented by transplantable mammary tumors, showed a much higher level of genomic instability, specifically a very high frequency (66%) of LOH on chromosome 4. These findings indicate that chromosome 4 harbors a gene whose inactivation may play a role in the acquisition of more aggressive characteristics such as autonomous growth and transplantation ability.

Age- and dose-dependent transplacental carcinogenesis by N-nitrosoethylurea in Syrian golden hamsters

Syrian golden hamsters have a very short period (15 days) of gestation. The implantation of the blastocyst occurs on day 5, embryogenesis proceeds very rapidly thereafter and neural tube closure is completed by day 9. In the present study the effects of two different doses of N-nitrosoethylurea (NEU) administered at various stages of gestation were quantitatively evaluated in Syrian golden hamsters. NEU at either 0.2 or 0.5 mmol/kg was administered transplacentally as a single i.p. injection to pregnant hamsters on gestation days 7, 8, 9, 10, 11, 12, 13, or 14. The incidence, latency period and multiplicity of tumors varied with the dose of NEU and the stage of development at the time of NEU administration. Although tumors of the peripheral nervous system predominated, a variety of other tumors, including melanomas and visceral tumors of epithelial and mesenchymal origin, were also observed in hamster offspring exposed transplacentally to NEU. Sensitivity to transplacental carcinogenesis was maximal during late gestation and very low before day 9.

High incidence and histogenesis of seminal vesicle adenocarcinoma and lower incidence of prostate carcinomas in the Lobund-Wistar prostate cancer rat model using N-nitrosomethylurea and testosterone

The origin of chemically induced male accessory sex gland tumors was studied in Lobund-Wistar rats. Rats were treated at the age of 3 months with a single intravenous injection of 30 mg N-nitrosomethylurea (NMU)/kg body weight and given subcutaneous silastic implants filled with 40 mg testosterone propionate. Previous reports described a high incidence of prostate carcinomas in these rats with this treatment protocol. Additional animal groups included untreated controls, rats that received only an injection of 30 mg NMU/kg, and rats that were subjected to ablation of the seminal vesicle lobes prior to the treatment with NMU and testosterone. Three to 14 rats per group were sacrificed 4 to 10 months after NMU treatment and all remaining rats after 12 months. Twenty-four additional rats died or became moribund during the study. All rats were necropsied and the dorsolateral and ventral prostate and seminal vesicles with coagulating gland (anterior prostate) were examined histologically according to a standardized protocol. Lesions detected included atypical hyperplasia in all glands (resembling prostate intraepithelial neoplasia of human beings), adenomas in seminal vesicles only, and early carcinomas and adenocarcinomas in seminal vesicles and coagulating gland. Early carcinomas of the seminal vesicle, microscopically small and with invasion of the lamina propria and/or tunica muscularis, were detected as rapidly as 4 months after treatment. The vast majority (> 95%) of the grossly visible nodules/masses originated from the seminal vesicles. Testosterone treatment enhanced occurrence and increased the incidence of all lesions, particularly of seminal vesicle adenocarcinomas, from 30% (7/23) to 64% (21/33). Coagulating gland tumors were found in 21% (7/33) of the rats. Ablation of the seminal vesicle lobes reduced the incidence of seminal vesicle adenocarcinomas to 11% (3/29), and these tumors arose from tissues remaining within the parenchyma of the seminal vesicle/prostate complex after ablation. Thus, NMU-induced and testosterone-promoted male sex gland tumors of the Lobund-Wistar rat arise almost exclusively in the seminal vesicles and coagulating gland (anterior prostate), are highly invasive in seminal vesicles before attaining a grossly visible size, and progress rapidly within 4 months, spreading to adjacent tissues and other organs.

Down-regulation of metallothionein expression in human and murine hepatocellular tumors: association with the tumor-necrotizing and antineoplastic effects of cadmium in mice

Previously, we found that oral cadmium (Cd) treatment either prevented or substantially reduced N-nitrosodiethylamine (NDEA)-induced tumor formation in B6C3F1 mouse liver or lung regardless of exposure interval and even when the Cd was given well after tumors were formed. Because Cd salts are powerful emetics, oral exposure would probably be impractical in humans. Thus, we studied suppression of NDEA-initiated tumors in male B6C3F1 mice by a single i.v. dose of Cd. NDEA (776 mumol/kg i.p.) was given at time 0 followed by CdCl2 (16 mumol/kg i.v.) 40 weeks later. This dose of Cd had no effect on body weights through the conclusion of the study at 52 weeks. The NDEA-induced increase in hepatic tumor incidence (19 tumor-bearing mice/22 mice at risk, 86%) over control (5/24, 21%) was remarkably reduced by Cd treatment (13/27, 48%, P < or = .05). Multiplicity and size of liver tumors induced by NDEA (2.18 tumors/liver; 31.6 mm3 mean volume) were also substantially reduced by the Cd exposure (0.96 tumors/liver; 17.1 mm3 mean volume). NDEA-induced lung tumor incidence (22/22, 100%) and multiplicity (5.09 tumors/lung) were modestly, but significantly, reduced by Cd treatment (21/27, 78%; 3.89 tumors/lung). Clear evidence of tumor-specific cytotoxicity was observed as Cd treatment induced a necrotizing effect that was localized only within the hepatic tumors. Metallothionein (MT), an inducible metal-binding protein associated with tolerance to many metal including Cd, was not detected immunohistochemically in mouse liver tumors, even those undergoing Cd-induced necrosis, whereas the surrounding normal liver cells expressed high levels of MT after Cd exposure. Likewise, in human hepatocellular carcinomas MT was only poorly or erratically expressed relative to normal tissue. These results indicate that a single, nontoxic dose of Cd dramatically reduces liver tumor burden through tumor cell-specific necrosis due to a down-regulation of MT expression in hepatic tumors of murine origin and furthermore indicate that a similar down-regulation of MT occurs in human hepatocellular carcinomas.

Mineralization of 2,4,6-trinitrophenol (picric acid): characterization and phylogenetic identification of microbial strains

Four bacterial strains that use picric acid as their sole carbon and energy source were isolated. Mineralization of 14C-UL-picric acid showed that up to 65% of the radioactivity was released as 14CO2. HPLC and UV/Vis spectral analyses indicated complete degradation of picric acid by these organisms. HPLC and LC/MS analyses showed transient formation of 2,4-dinitrophenol during picric acid degradation. Degradation of picric acid was concomitant with stoichiometric release of three moles of nitrite per mole of picric acid. The four picric acid degraders were identified as close relatives of Nocardioides simplex (ATCC 6946) based on their small subunit (16S) rRNA gene sequences.

Cadmium and prostate cancer

Prostatic cancer is a common and frequently lethal malignant disease. In the United States and other countries the incidence and mortality rate of prostate cancer continue to rise. Cancer of the prostate has an extremely complex etiology and appears dependent on a variety of factors, making linkage to a single factor very difficult to detect. Cadmium is a metallic toxin of great environmental and occupational concern. Cadmium exposure has been associated with human prostatic cancer in some, but not all, epidemiologic studies. Some studies indicate that tissue levels of cadmium in the human prostate correlate with malignant disease. Any association between cadmium and prostatic cancer has been controversial, in large part because of a previous lack of relevant animal models. However, several chronic studies in rats revealing a correlation between cadmium exposure and prostatic tumors have been published over the last several years. These include a study of oral cadmium exposure, a route extremely relevant to human exposure. Several of these chronic studies indicate a hormonal dependence of cadmium-induced prostate cancer. Other supportive work continues to accumulate, such as studies showing in vitro malignant transformation of prostatic epithelial cells with cadmium exposure. In addition, there are indications that the primary biologic tolerance system for cadmium (i.e., the metallothionein gene) may be only poorly active in the specific lobes of the rat prostate in which cadmium induces tumors. The induction in rats of prostate cancer by cadmium treatment clearly supports, but does not definitively establish, a possible role for cadmium as an etiological agent in human prostate cancer. Further research, however, will be required to establish the precise role of cadmium in this important human malignancy.

Squamous metaplasia of bronchiolar cell-derived adenocarcinoma induced by N-nitrosomethyl-n-heptylamine in Syrian hamsters

Morphology and development of experimental bronchiolar lung tumors were studied in Syrian hamsters, using light and electron microscopic techniques. At the age of 9 weeks, 46 hamsters were each given one weekly gavage of 6.8 mg N-nitrosomethyl-n-heptylamine for 35 weeks, and hamsters were examined at intervals from 2 to 46 weeks. The present report describes the progression of adenocarcinomas of bronchiolar cell origin to adenosquamous and squamous cell carcinomas. Squamous metaplasia was commonly noted at the tumor periphery, i.e., zone of growth. In 20 hamsters, 22 adenosquamous and two squamous cell carcinomas (one a large cell carcinoma) were diagnosed by light microscopy. Overt keratinization was infrequent. Squamous cell metaplasia was not a feature of papillary neoplasms but was seen mainly with acinar structures. Ultrastructurally, squamous differentiation (metaplasia) appeared to develop along two different pathways. First, secretory cells were observed with large numbers of intermediate filaments and tonofilaments, with concurrent loss of organelles such as secretory granules and microvilli. Second, squamous metaplasia also appeared to develop from a progeny of tumor cells that failed to mature into secretory cells. Such cells were often present within the basal layer of secretory acini and resembled basal cells of the tracheobronchial tree. These observations were supported by increased expression of cytokeratins, as revealed by immunohistochemical procedures. Immunoelectron microscopic examination localized hamster Clara cell antigen in secretory granules of neoplastic Clara cells, in the cytoplasm between granules, and at the microvillous border. With the onset of squamous differentiation, Clara cell antigen was progressively lost from secretory cells and was only rarely seen in cells with tonofilaments. No labeling was present in squamous cells arising at the base of tumor acini. These results suggest that pulmonary squamous cell carcinomas may develop by direct squamous differentiation of secretory cells or may proceed from undifferentiated tumor cells.

Sensitivity to second dose of mivacurium

The sensitivity of patients to a second dose of mivacurium has been studied following complete recovery of the twitch response after > 95% neuromuscular block produced by a systemic bolus of the drug. In further experiments we have excluded one arm from the effect of a systemic bolus ED95 dose of mivacurium for 100 s so as to obtain two different levels of neuromuscular block in the two arms of the same patient. Upon recovery from the block in the paralysed arm the dose response of both arms to a second dose of mivacurium was studied in order to investigate the effect of the amount and duration of block upon second dose sensitivity. An approximately 50% diminution in the ED95 dose requirement of mivacurium was found following complete recovery from an ED95 dose in spite of the rapid plasma clearance of this drug. A similar increase in sensitivity was observed in the arm that had been excluded for 100 s from the peak effect of the drug. It was concluded that the second dose sensitivity was not due to a receptor effect or to residual drug in plasma.

Chronic toxic and carcinogenic effects of cadmium chloride in male DBA/2NCr and NFS/NCr mice: strain-dependent association with tumors of the hematopoietic system, injection site, liver, and lung

Although the acute toxic effects of cadmium in mice vary greatly with strain, relatively little is known about strain differences in cadmium carcinogenesis. Therefore, this work was performed to assess the chronic toxic and carcinogenic effects of cadmium in two strains of mice generally thought to be susceptible to the acute effects of cadmium. Male DBA/2NCr (DBA) and NFS/NCr (NFS) mice were given CdCl2 (40 mumol/kg, sc) either as a single dose (1 x 40) or as weekly doses for 16 weeks (16 x 40) starting at 8 weeks of age. Controls received saline. The animals were observed for the next 104 weeks and mice at risk were defined as those surviving to the time of appearance of a particular tumor. Cadmium-induced dose-related increases in lymphoma (primarily follicular center cell) incidence (1 x 40, 11 cases/23 mice at risk; 16 x 40, 16/28) over control (7/27) in DBA mice but not in NFS mice. Only NFS mice receiving repeated cadmium injections (16 x 40) showed sarcoma development at the injection site (9/35), as no sarcomas occurred in control NFS mice or any group of DBA mice. On the other hand, cadmium-treated (16 x 40) NFS mice, but not DBA mice, had more hepatocellular adenomas and carcinomas (9/27) than control (1/15) but only at the high dose (16 x 40). More cadmium-treated NFS mice had pulmonary tumors than controls, but only at the lower dose (1 x 40). Although testicular tumors were rare, nonneoplastic lesions (fibrosis and mineralization) were induced by cadmium to a similar extent in both strains. Clearly cadmium carcinogenicity varies widely with strain, indicating a genetic basis to susceptibility. The basis of these strain differences deserves further study.

Effect of chlorpromazine pretreatment on cadmium toxicity in the male Wistar (WF/NCr) rat

A recent report has indicated that cadmium-induced testicular damage in CF-1 mice can be prevented by pretreatment with calmodulin inhibitors such as chlorpromazine (CPZ), trifluoperazine, or N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide (W-7). However, the basis of this tolerance to cadmium is unclear and has not been demonstrated in any species other than mice. Thus, we examined the effects of the calmodulin inhibitor CPZ on cadmium toxicity in male Wistar (WF/NCr) rats. A single sc injection of 25 mumol CdCl2/kg proved nonlethal over 24 h but caused the typical spectrum of testicular lesions and increases in hemoglobin content (as assessed by hemoglobin absorbance in testicular supernatant). Pretreatment with 40 mumol CPZ/kg had no effect on cadmium-induced testicular lesions but did reduce testicular hemoglobin content, while 120 mumol CPZ/kg moderately reduced the severity of testicular lesions and hemoglobin contents. CPZ pretreatment in some cases increased cadmium content in liver and reduced testicular content but had no effect on renal levels. Cadmium treatment markedly increased hepatic and renal metallothionein (MT), a metal-binding protein often associated with tolerance to cadmium. CPZ alone likewise increased hepatic MT and MT mRNA, but did not modify renal MT, renal MT mRNA, or testicular MT mRNA. In contrast to liver and kidney, testicular cadmium-binding protein (TCBP) decreased in rats exposed only to cadmium or to CPZ, while CPZ pretreatment had no further effect on cadmium-induced reductions in TCBP levels. These results indicate that, like mice, CPZ in rats can reduce the testicular toxicity of cadmium as indicated by CPZ-induced reductions in testicular vascular lesions and hemoglobin contents. However, in rats CPZ has a less dramatic effect on such cadmium-induced lesions than in mice. The CPZ-induced stimulation of hepatic MT gene expression or modification of toxicokinetics may both play roles in this acquired tolerance to cadmium.

Cytopathologic and neurochemical correlates of progression to motor/cognitive impairment in SIV-infected rhesus monkeys

Neurochemical, pathologic, virologic, and histochemical correlates of simian immunodeficiency virus (SIV)-associated central nervous system (CNS) dysfunction were assessed serially or at necropsy in rhesus monkeys that exhibited motor and cognitive deficits after SIV infection. Some infected monkeys presented with signs of acquired immunodeficiency disease (AIDS) at the time of sacrifice. Seven of eight animals exhibited motor skill impairment which was associated with elevated quinolinic acid in cerebrospinal fluid (CSF). Examination of the brains revealed diffuse increases in glial fibrillary acidic protein immunoreactivity in cerebral cortex in all animals, regardless of evidence of immunodeficiency disease. Reactive astrogliosis preceded or was coincident with the onset of neuropsychological impairments. Virus rescue from CSF of six of eight infected animals showed that one of three animals with AIDS and none of three animals without AIDS at necropsy had virus rescue-positive CSF. Multinucleated giant cells were seen in the brain of only one animal with end-stage AIDS and high systemic virus burden at death. Neither systemic nor CNS virus burden was associated with the onset of CNS dysfunction. SIV-associated motor/cognitive impairment is associated with subtle, widespread changes in CNS cytology and neurochemistry, rather than with large increases in brain virus burden or widespread virus-associated brain lesions.

Clara cell antigen in normal and migratory dysplastic Clara cells, and bronchioloalveolar carcinoma of Syrian hamsters induced by N-nitrosomethyl-n-heptylamine

Histogenetic features of lung tumours were studied in Syrian hamsters that had been induced with 6.8 mg N-nitrosomethyl-n-heptylamine/animal by gavage once a week for 35 weeks. At intervals from experimental week 2 until week 46, pulmonary tissues from hamsters were examined by light and electron microscopy. This report describes early hyperplastic lesions associated with terminal bronchioles and the progression of these lesions to bronchioloalveolar tumours. Using immunohistochemical and ultrastructural colloidal gold labelling techniques, hamster Clara cell antigen was found to be localized in Clara cell granules and smooth endoplasmic reticulum of normal cells, in dysplastic Clara cells migrating through basement membrane defects or from the open end of terminal bronchioles, and in hyperplastic peribronchiolar cell foci. The latter progressed to bronchioloalveolar tumours growing out along alveolar basement membranes in a characteristic lace-like, lepidic pattern. Tumours were composed of secretory (Clara), ciliated, mucous, and undifferentiated cells, as well as trapped, non-neoplastic alveolar type II cells. Hyperplastic neuroendocrine cell foci lining airways were immunoreactive for chromogranin, but these cells did not participate in the pre-neoplastic or neoplastic process. It is suggested that bronchioloalveolar carcinomas in hamsters are derived from bronchiolar secretory (Clara) cells growing along alveolar walls, differentiating into other bronchiolar cell types and entrapping resident alveolar type II cells. Due to the migratory capacity of Clara cells, it is also possible for tumours composed of bronchiolar cells to develop at the lung periphery.

Transplacental carcinogenicity of cisplatin: initiation of skin tumors and induction of other preneoplastic and neoplastic lesions in SENCAR mice

cis-Dichlorodiammineplatinum (cis-DDP), an anticancer agent sometimes used in pregnant women for the treatment of malignant ovarian and uterine tumors, was tested for transplacental carcinogenic and/or tumor-initiating effects in SENCAR mice. Pregnant mice were given a single i.p. injection of either cis-DDP (7.5 mg/kg body weight) in 2.5% NaCl or the same weight-adjusted volume of NaCl (5 ml/kg body weight) on day 17 of gestation. Offspring were delivered and raised by their natural mothers until weaning at 3 weeks of age. Starting at week 4, offspring in experimental groups received topical applications of 2 micrograms 12-O-tetradecanoylphorbol-13-acetate (TPA) in acetone twice a week for 20 weeks while those in control groups received only acetone (0.2 ml/application) for the same duration. The experiment was terminated at 25 weeks of age. A high incidence (18 of 37; 48.7%) of papillomas was observed in offspring exposed transplacentally to cis-DDP and postnatally to TPA, while only 10% (4 of 40) of offspring exposed to TPA alone developed such tumors (P < 0.0002). Although no skin tumors were observed without TPA promotion, transplacental administration of cis-DDP resulted in development of thymic lymphomas, lung tumors, and proliferative kidney lesions in offspring. These results provide the first evidence that cis-DDP can initiate and/or induce preneoplastic and neoplastic lesions in multiple tissues transplacentally.

Diagnostic utility of lactate dehydrogenase levels in patients receiving aerosolized pentamidine

Serum lactate dehydrogenase (LDH) levels are elevated in patients with Pneumocystis carinii pneumonia (PCP). In patients receiving aerosolized pentamidine (AP), PCP may be less severe and present with more localized radiographic infiltrates. We evaluated the diagnostic utility of the serum LDH level in 11 patients developing PCP while receiving AP. Serum LDH levels were increased 72.7 +/- 19.0 percent over mean baseline levels and 76.4 +/- 26 percent over the upper limit of normal value for our laboratory with the development of PCP. An elevated serum LDH value remains a useful diagnostic adjunct in the patient developing PCP while receiving AP. Isolated LDH values must be interpreted with caution given the potential for marked variability in the baseline LDH value.

Infiltrating angiolipoma of skeletal muscle. Transplacental induction in nonhuman primates by N-nitrosoethylurea

BACKGROUND

In humans, relatively little is known on the association of prenatal exposure to cancer-causing agents and the development of specific tumors later in life as a consequence. Therefore, the effects on the offspring of carcinogen exposure during gestation and the development of tumors later in life were studied in nonhuman primates.

EXPERIMENTAL DESIGN

Pregnancy was confirmed in Erythrocebus patas (patas) and Macaca mulatta (rhesus) by palpation at 27 to 40 days of gestation. Pregnant animals were treated once weekly intravenously from that time with N-nitrosoethylurea according to different dosing regimens for 6 to 19 weeks with 0.05 to 0.2 mmol/kg/injection.

RESULTS

A common lesion developing in only the offspring of mothers treated early in pregnancy was identical with the human condition referred to as intramuscular angioma, hemangioma, or infiltrating angiolipoma of skeletal muscle. In the rhesus, one of 7 animals, and in the patas, 18 of 78 monkeys developed these processes (10 to 40% per group). The lesions typically arose within, infiltrated and displaced skeletal muscle. They occurred most commonly in the lower extremities, followed by the upper extremities and the head; they recurred in three cases of incomplete resection but did not metastasize. The tumors were seen mainly in young adults of both sexes (latency range: 4 to 76 months) and consisted of vessels of variable caliber, and to varying degrees, mature adipose and connective tissue, undifferentiated mesenchymal cells, and lymphoid cell aggregates. Ultrastructurally, the endothelium possessed numerous Weibel-Palade bodies and showed strong immunoreactivity for von Willebrand factor by immunohistochemistry and immunoelectron microscopy.

CONCLUSIONS

The present investigation suggests a classification of these lesions as infiltrating angiolipoma of skeletal muscle originating from a pluripotent mesenchymal stem cell, caused by exposure to carcinogens during early pregnancy. The great clinical and morphologic similarity of this condition with that observed in humans suggests that it may likewise be caused by exposure to an agent during pregnancy.

Development of an animal model for testing human breast implantation materials

Although breast implant materials have been tested in laboratory species since the early 1950s, a standardized evaluation system does not currently exist in which human-made polymers are exposed directly to the mammary milieu of female animals. The present study evaluated such a model as the basis for future experiments on long-term tissue effects. Polyesterurethane disks, 6 mm in diameter x 3 mm thick, were inserted bilaterally beneath the axillobrachial and inguinal mammary/fat pads of 50 9-wk-old female B6D2F1 mice (4 implants each). Implant sites were examined histologically at time points 24 hr to 47 wk after surgery. An acute inflammatory reaction at the implant edges began within 24 hr, and macrophages were found lining the smooth polyurethane fiber surfaces at the periphery by day 2. Multinucleated foreign body giant cells formed by day 4, and by week 4 giant cells contained polyurethane fragments within the cytoplasm, implying degradation of the material. Implant sites showed declining subacute inflammatory responses and increasing fibrosis by week 5. By 13 wk, the polyurethane disks appeared to be integrated into the growing adipose and mammary tissues. Although not apparent on gross inspection, microscopic examination showed that polyurethane fibers moved progressively into adjacent tissues and were always associated with chronic granulomatous inflammation. Histologic findings in the present study are strikingly similar to the human response to polyurethane-coated breast implants. These results suggest the applicability of this model to appropriately test mammaplasty materials in mammary tissues.

Acute effects of 4-ipomeanol on experimental lung tumors with bronchiolar or alveolar cell features in Syrian hamsters or C3H/HeNCr mice

4-Ipomenaol (IPO) has been shown to induce P-450-mediated necrosis of Clara cells in experimental animals, and clinical trials were initiated to treat people with bronchioloalveolar cancers with this novel drug. We therefore performed experiments to examine two different animal lung tumor models for acute IPO cytotoxicity: hamster Clara-cell-derived adenocarcinomas and mouse alveolar type II cell tumors. Clara cells serve as stem cells for airway cell renewal and, therefore, tumors derived from Clara cells may likewise differentiate into various bronchiolar cell types, or undergo squamous cell metaplasia. Bronchiolar cell tumors were induced in Syrian hamsters by a single weekly gavage with 6.8 mg N-nitrosomethyl-n-heptylamine (NMHA)/animal for 35 weeks. NMHA-induced bronchiolar tumors were classified as well-differentiated lepidic bronchioloalveolar carcinomas, acinar adenocarcinoma, adenosquamous carcinoma, and squamous-cell carcinoma. After 35 and 46 experimental weeks, control and carcinogen-treated hamsters were injected once with doses of 40-110 mg IPO/kg i.p. and necropsied 15-48 h later. Solid and papillary tumors with alveolar cell features were induced transplacentally in C3H/HeNCr mice, by treating pregnant animals on gestation day 16 with 0.5 mmol N-nitrosoethylurea/kg, i.p. Offspring of control and carcinogen-treated mice were injected at 2-3 months of age with 35 mg or 50 mg IPO/kg i.p. and necropsied either 24-48 h or 5 and 12 days after injection. Light microscopic studies were carried out to assess cytotoxic effects in various tissues in both hamsters and mice; in hamsters, additional ultrastructural studies were performed. When administered to hamsters, IPO induced moderate to severe cytotoxicity in normal and dysplastic bronchiolar lining cells, in most lepidic bronchioloalveolar carcinomas, and in some glandular areas of adenosquamous cell carcinomas. Susceptible cells included normal, anaplastic, and neoplastic nonciliated and some ciliated bronchiolar cells. Undifferentiated and squamous tumor cells were resistant to IPO, as were resident normal alveolar type II cells. However, some adenocarcinomas composed primarily of ciliated and mucous cells also showed no IPO-induced necrosis, indicating a deficiency in appropriate activating enzymes. In the mice, IPO induced bronchiolar cell necrosis and, at the high dose, also severe pulmonary edema. No cytotoxicity was observed in normal or hyperplastic alveolar epithelium, nor in either solid or papillary growth forms of mouse alveolar cell tumors.(ABSTRACT TRUNCATED AT 400 WORDS)

Carcinogenicity of oral cadmium in the male Wistar (WF/NCr) rat: effect of chronic dietary zinc deficiency

The effect of chronic dietary zinc deficiency on the carcinogenic potential of dietary cadmium was assessed in male Wistar (WF/NCr) rats. Groups (n = 28) of rats were fed diets adequate (60 ppm) or marginally deficient (7 ppm) in zinc and containing cadmium at various levels (0, 25, 50, 100, or 200 ppm). Lesions were assessed over the following 77 weeks. Zinc deficiency alone had no effect on survival, growth, or food consumption. Cadmium treatment did not reduce survival or food consumption and only at the highest doses of cadmium (100 and 200 ppm) was body weight reduced (maximum 17%). The incidence of prostatic proliferative lesions, both hyperplasias and adenomas, was increased over that seen in controls (1.8%) in both zinc-adequate (20%) and zinc-deficient rats (14%) fed 50 ppm cadmium. The overall incidence for prostatic lesions for all cadmium treatment groups was, however, much lower in zinc-deficient rats, possibly because of a marked increase in prostatic atrophy that was associated with reduced zinc intake. Cadmium treatment resulted in an elevated leukemia incidence (maximum 4.8-fold over control) in both zinc-adequate and zinc-deficient groups, although zinc deficiency reduced the potency of cadmium in this respect. Testicular tumors were significantly elevated only in rats receiving 200 ppm cadmium and diets adequate in zinc. Both zinc-deficient and zinc-adequate groups showed significant positive trends for development of testicular neoplasia with increasing cadmium dosage. Thus, oral cadmium exposure is clearly associated with tumors of the prostate, testes, and hematopoietic system in rats, while dietary zinc deficiency has complex, apparently inhibitory, effects on cadmium carcinogenesis by this route.