Continuous intravenous infusion in athymic (nude) rats: an animal model for evaluating the efficacy of anti-cancer agents.

The athymic (nude) rat (rnu/rnu) has been used for a number of years in research into various human tumours involving xenotransplantation. We now report the validation of a continuous intravenous infusion method in nude rats using a tail cuff tether, which enables the study of the efficacy of novel anti-cancer materials in this mutant strain, using intravenous infusion and with no restriction of the animals or of the tumour implantation sites by jackets. Ten animals each had a cannula surgically implanted into the vena cava via the femoral vein and exteriorized via a tail cuff. Animals were housed singly in conventional cages following surgery. Following a recovery period of 5 days all animals were continuously infused with physiological saline at an infusion rate of 0.5 ml/h for a further 37 days. Body weights and food consumption were recorded weekly. Blood samples were taken approximately 14 days post-surgery and analysed for haematology and clinical chemistry parameters. All animals were successfully cannulated, and no unexpected adverse clinical signs were noted during the recovery period and the 37 days of infusion. The results demonstrate that it is possible to surgically cannulate the femoral vein of athymic (nude) rats and infuse them in conventional cages for a period of up to 37 days with minimal adverse effects. The minimal restraint required provides benefits both to the animal and to the conduct of studies such as assessment of tumour growth in the absence of a jacket. Recent work has demonstrated that the same techniques can be successfully applied to the nude mouse.

Single- and repeated-dose local toxicity in the nasal cavity of rabbits after intranasal administration of different glycols for formulations containing benzodiazepines.

To furnish a systemic effect after intranasal administration, a formulation must contain the therapeutic dose in no more than 150 L, the maximum volume that can be applied as a single administration in one nostril in man. The objectives of these studies were to examine the local toxicity of formulations containing benzodiazepines and to document the effects to support clinical trials in man. After stability, pharmacological and pharmacokinetic studies of several benzodiazepine formulations, we studied nasal toxicity after single and repeated administration to rabbits of poly(ethylene glycol) 200, tetra(ethylene glycol), glycofurolum and mixtures of these vehicles both with and without benzodiazepines. Single-dose studies with examinations 5 or 10min after application were undertaken with poly(ethylene glycol), tetra(ethylene glycol), glycofurolum and tetra(ethylene glycol)-glycofurolum in the ratio 95:5; the reactions were similar to that after physiological saline. A 14-day repeated-dose study was conducted with diazepam, lorazepam and flunitrazepam formulations in poly(ethylene glycol), and flunitrazepam in poly(ethylene glycol)-glycofurolum in the ratio 70:30; the two vehicles without any benzodiazepine were also examined. Microscopic study revealed mild changes only in the treated groups. A final four-week study was conducted with repeated administration of clonazepam formulated in tetra(ethylene glycol)-glycofurolum in the ratio 95:5; microscopy revealed mild changes after three 150-microL doses daily, but no abnormalities after one or three 100-microL doses daily. It was concluded that these three solvents individually or as mixtures resulted in only mild local toxicity and might be acceptable as vehicles in nasal preparations of benzodiazepines and other non-irritating drugs for short-term use in man.

Preliminary assessment of fluorine-18 fluorodeoxyglucose positron emission tomography in patients with bladder cancer.

The purpose of this study was to assess the feasibility of imaging of bladder cancer with fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) scanning. We studied 12 patients with histologically proven bladder cancer who had undergone surgical procedures and/or radiotherapy. Retrograde irrigation of the urinary bladder with 1000-3710 ml saline was performed during nine of the studies. Dynamic and static PET images were obtained, and standardized uptake value images were reconstructed. FDG-PET scanning was true-positive in eight patients (66.7%), but false-negative in four (33.3%). Of 20 organs with tumor mass lesions confirmed pathologically or clinically, 16 (80%) were detected by FDG-PET scanning. FDG-PET scanning detected all of 17 distant metastatic lesions and two of three proven regional lymph node metastases. FDG-PET was also capable of differentiating viable recurrent bladder cancer from radiation-induced alterations in two patients. In conclusion, these preliminary data indicate the feasibility of FDG-PET imaging in patients with bladder cancer, although a major remaining pitfall is intense FDG accumulation in the urine.

Chronic (1-year) oral toxicity study of erythritol in dogs.

The chronic oral toxicity of erythritol was examined by feeding erythritol at dietary levels of 0 (controls), 2, 5, or 10% to groups of four male and four female dogs for 53 weeks. Erythritol was well tolerated at all dose levels without evidence of diarrhea. Water consumption was slightly higher in the high-dose group than in controls. Body weights and weight gains were not affected by treatment. There were no clinically relevant changes in hematological or clinicochemical parameters attributable to treatment. In particular, plasma electrolyte concentrations remained unaffected. Evaluation of a number of urinary parameters (including electrolytes and renal enzymes) was hampered by widely varying urine volumes among individual dogs; however, the available data did not indicate treatment-related effects on the urinary excretion of electrolytes (K+, Na+, Mg2+, and Pi) or enzymes (gamma-glutamyltranspeptidase, N-acetyl glucosaminidase, and lactate dehydrogenase). Quantitation of erythritol in the urine demonstrated that 50 to 80% of the ingested dose was absorbed and excreted in the urine. Analysis of terminal organ weights did not reveal treatment-related differences. No histopathological changes attributable to treatment were observed in the kidneys or in any other organ or tissue examined. It was concluded that daily erythritol consumption of up to 3.5 g/kg body wt was well tolerated by dogs.

Safety evaluation of a lipase expressed in Aspergillus oryzae.

A programme of studies was conducted to establish the safety of a lipase artificially expressed in Aspergillus oryzae to be used in the detergent industry and as a processing aid in the baking industry. Laboratory animal studies were used to assess general and inhalation toxicity, skin sensitization, and skin and eye irritation. Its potential to cause mutagenicity and chromosomal aberrations was assessed in microbial and tissue culture in vitro studies. The pathogenicity of A. oryzae, the organism used to produce the lipase, was also assessed in laboratory animals. Basic ecotoxicity in a variety of test species was studied. General and inhalation toxicity was low. There was evidence of mild skin irritation. There was no evidence of eye irritation, skin sensitization, mutagenic potential, chromosomal aberrations, exotoxicity or notable pathogenicity. Comparison of these results with human exposure levels and previously published data indicates that the lipase appears safe for consumers in the given applications, requires no special occupational health precautions in manufacture and is of low environmental impact. Furthermore, the organism used in production of the lipase hs no notable pathogenicity.

Staging of mediastinal non-small cell lung cancer with FDG PET, CT, and fusion images: preliminary prospective evaluation.

PURPOSE: To evaluate use of positron emission tomography (PET) with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) in detection of mediastinal lymph node metastases from non-small cell lung cancer. MATERIALS AND METHODS: A prospective trial to compare FDG PET and computed tomography (CT) of the thorax was performed in 23 patients with newly diagnosed or suspected non-small cell lung cancer. Blinded interpretations of CT alone, PET alone, CT and PET together, and fusion images were performed, and the results were compared with pathologic results. RESULTS: Nineteen of 23 patients had non-small cell lung cancer. Prevalence of mediastinal involvement was 41%. In staging disease in the mediastinum, CT alone was 64% sensitive, 44% specific, and 52% accurate, whereas PET alone and fusion images were 82% sensitive, 81% specific, and 81% accurate (P < .05). CONCLUSIONS: FDG PET was more accurate than CT in staging disease in the mediastinum in patients with lung cancer and appears to be the preferred imaging method in this clinical setting.

Detection of deep venous thrombi and pulmonary embolus with technetium-99m-DD-3B6/22 anti-fibrin monoclonal antibody Fab' fragment.

UNLABELLED: Technetium-99m-labeled anti-fibrin DD-3B6/22 Fab' monoclonal antibody fragments, which specifically target human cross-linked fibrin with high affinity, were evaluated in humans for safety and their capacity to detect deep vein thrombi and pulmonary embolism. METHODS: Twenty patients with proven deep-vein thrombosis, documented by contrast venography, or venous duplex scan, were injected with a 600 MBq (0.5 mg) dose of antibody. Planar images of the lower limbs were recorded at 0, 2, 6 and 24 hr and chest scintigrams were recorded at 6 and 24 hr. RESULTS: All venography documented thrombus sites, calves, popliteal and femoral, were detected with the radioimmunoconjugate. For the venous duplex scan-proven thrombus sites, all except two calf thrombi in two patients with bilateral disease and other positive sites were detected. Five patients had bilateral deep-vein thrombosis with multiple sites being visualized with the radioimmunoconjugate in the calf, popliteal and femoral regions. One case of pulmonary embolus was also definitively demonstrated. Documented thrombus sites were detected at 2 and 6 hr postinjection. Nineteen patients were on heparin. No adverse reactions to the injected dose were observed and one low titer human anti-mouse antibody response may have occurred. CONCLUSION: The results indicate that 99mTc-DD-3B6/22 Fab' has potential for noninvasive detection of deep-vein thrombosis and pulmonary embolism.

Comparison of independent aura, ictal and interictal cerebral perfusion.

Technetium-HMPAO cerebral SPECT was performed interictally, immediately after an independent aura and ictally in a patient with complex partial seizures. Interictally there was a left inferior frontoparietal region of decreased perfusion. Ictally there were a number of foci of increased perfusion. The aura study showed focal hyperperfusion in the left frontal region and decreased perfusion in the adjacent cortex posteriorly, suggesting a zone of suppression. This may be the cause or effect of the nonprogression of the aura. The case raises the possibility that cerebral perfusion studies performed immediately after independent auras may localize seizure foci if ictal studies are nonfocal.

Safety evaluation of alkaline cellulase.

A programme of studies was conducted to establish the safety of alkaline cellulase, an enzyme used as a processing aid in the food industry. Laboratory animal studies were used to assess general, inhalation and reproduction toxicity, eye irritation and skin irritation and sensitization. Mutagenic potential was assessed in microbial and animal in vivo studies. The pathogenicity of Humicola insolens, the micro-organism used in the production of alkaline cellulase, was also assessed in laboratory animals. Basic ecotoxicity in a variety of test species was studied. General toxicity by a variety of routes was low; there was no evidence of reproductive toxicity. There was evidence of mild skin irritation and some eye conjunctival reddening. There was no evidence of skin sensitization, mutagenic potential, ecotoxicity or notable pathogenicity. When these results are considered along with levels of human exposure and previously published data, it appears that alkaline cellulase is safe for consumers in the given applications, requires no special occupational health precautions in manufacture, and is of low environmental impact. Furthermore, the micro-organism used in production of alkaline cellulase has no notable pathogenicity.

Current role of gallium scanning in the management of lymphoma.

Gallium 67 scanning in the malignant lymphomas has been done, with variable success, for over 20 years. After initial enthusiasm, the technique fell into disrepute and it was not until the early 1980s that it enjoyed a revival. There have been many major contributions to the literature, both favourable and unfavourable. The reasons for the latter include: poor instrumentation (only single-pulse height analysis), low gallium 67 doses, impatient and careless scanning techniques, timing of the study after treatment (chemotherapy, radiation) and insensitive methods of confirmation of the presence or absence of disease ("truth"). Anatomical diagnostic techniques (computed tomography, plain X-radiography, magnetic resonance imaging and others) are incapable of distinguishing viable tumour in normal-size lymph nodes or necrotic/fibrotic residual masses. With improvements in instrumentation (triple-pulse height analysis, gamma camera resolution and tomographic techniques) gallium 67 can detect active tumour in residual masses and in normal-size nodes. This is due to gallium 67's unique ability to localize in viable tumour cells. It has greater than 90% sensitivity, specificity, accuracy and positive predictive value in patients with lymphoma. Its major contributions are in: staging (changing management of mediastinal disease, obviating the need for a laparotomy and clearly identifying stage IV disease); detecting relapse or residual, progressive disease (it establishes true complete remission and is often the first and only evidence of relapse before clinical evidence); predicting response to therapy (failure to convert to a negative scan post-treatment signals a poor prognosis and alternative therapy is required); and predicting outcome--prognosis (it is the only diagnostic modality to predict outcome accurately).

Biosynthetic human growth hormone: subchronic toxicity studies in rats and monkeys.

Biosynthetic human growth hormone was injected subcutaneously in rats for 90 days and in cynomolgus monkeys for 30 days. The daily doses were 0.5, 3.3 and 25 IU kg-1 (rats) and 0.3 and 15 IU kg-1 (monkeys). The growth hormone was tolerated well in both rats and monkeys. No drug related deaths occurred and all animals appeared to be normal and also behaved normally throughout the dosing period. Increased body weight gain, increased food utilisation and increased organ weights were seen in the rats in the high and intermediate dose groups. The higher doses of human growth hormone (3.3 and 25 IU kg-1) caused a glandular hyperplasia of the mammary gland in male and female rats with evidence of secretory activity. In the female monkeys secretory activity was seen without any sign of mammary gland hyperplasia. Mucification of the vaginal epithelium and stress induced prostatitis was observed in the rats. Additional treatment related changes in the rats were an increased haematopoietic activity in the spleen and an increase in the amounts of calcium and phosphate excreted in urine. An increase in fasting plasma glucose levels was seen in the male monkeys on the high dose level. The changes observed during the treatment periods presumably represent exaggerated pharmacological effects of the growth hormone.

Thermal decomposition of thonzonium bromide.

Thonzonium bromide, a quaternary ammonium compound used as a surface active agent in a phenylephrine nasal solution, gave a gas chromatographic peak which was proportional in height and area to its concentration. Quaternary ammonium salts are nonvolatile and polar, thus the peak was attributed to a thermal decomposition product. It was identified as hexadecyldimethylamine by spectroscopic analysis and comparison with an authentic sample. A second product was identified by mass spectroscopy as 2[(2-hexadecylmethylaminoethyl)(4-methoxybenzylamino)] pyrimidine, the desmethyl bromide product. These decomposition products were detected in stability samples of formulations.

Toxicological Safety Evaluation of a Bacillus acidopullulyticus Pullulanase.

Promozyme®, an amylopectin debranching enzyme produced by Bacillus acidopullulyticus , was studied to evaluate its safety in the food industry. A dietary subchronic toxicity study incorporating fertility and teratogenicity studies was performed in 1-month-old rats at concentrations of 0.5, 1.5 and 5% Promozyme. No adverse effects were seen at the 0.5 and 1.5% dose levels, and at the 5% dose level only minor or equivocal signs of toxicity were recorded. With the exception of a moderate reduction in body weight gain the FIA litters at the 5% dose level, no effects were found in the fertility study, and Promozyme was not teratogenic. In a 13-wk oral toxicity study in dogs, no adverse effects resulted from 0.5 g/kg/d, whereas mild gastrointestinal disturbances were seen clinically at 1.5 and 5.0 g/kg/d. In dogs given 5.0 g/kg/d, terminal investigations showed increased kidney weights and mineralized casts in renal cortical tubules. This was probably due to the high content of ash (phosphorus) in the test material. Lack of mutagenic potential was confirmed in bacterial mutagenic assays with Salmonella typhimurium (TA 1535, TA 1537, TA 1538, TA 98 and TA 100) and in an in vivo cytogenetic study in rat bone marrow cells after a single dose and daily dosing for 5 d of up to 8 g/kg/d. In an acute inhalation study with 4 h of exposure of rats, no death occurred at the highest dose level used, i.e., 2 mg/L. The test material was non-irritating to skin and did not produce eye injury in rabbits. A skin sensitization study in guinea pigs revealed no indication that the enzyme is a sensitizer. The pathogenic potential of the enzyme-producing B. acidopullulyticus was investigated by single intraperitoneal and subcutaneous administrations to rats and mice; the microorganism was found to be nonpathogenic (LD50>1010 cells/kg). Tests of culture broths revealed that the microorganism does not produce antibiotics. Results indicated that production and the intended use of Promozyme can be regarded as safe for plant workers and consumers.

Bunolol metabolism by dogs: urinary excretion of 5-hydroxytetralone.

1. Anion exchange and t.l.c. were used to collect the polar drug metabolites present in urine of dogs treated orally with [14C]bunolol. 2. A new metabolite, 5-hydroxytetralone, was isolated, purified, and identified by u.v.,i.r. and mass spectroscopy. 3. 5-Hydroxytetralone represented 1.7% dose excreted in urine collected for 24 h after bunolol administration. 4. Properties of the metabolite are discussed in relation to the question of whether 5-hydroxytetralone was excreted as a conjugate.

Bunolol metabolism by dogs: identification of basic metabolites and their conjugates.

Female beagles dosed once with encapsulated 14C-bunolol (10 mg/kg) excreted 61% of the isotope in urine in 24 hr. The pooled urine contained a minimum of 18 labeled compounds. Two previously unknown metabolites were purified and were identified by UV and mass spectral data; they were hydroxybunolol (10.1% of urinary radioactivity) and hydroxydihydrobunolol (9.8%). The urine also contained bunolol (0.7% of urinary carbon-14), dihydrobunolol (0.5%), conjugated dihydrobunolol (2.8%), beta-(5-oxytetralonyl)lactic acid (16.3%), and (5-oxytetralonyl) acetic acid (7.1%).

Ambruticin (W7783), a new antifungal antibiotic.

Ambruticin represents a new class of antibiotics isolated from a strain of Polyangium cellulosum var, fulvum, a bacterium belonging to the class Myxobacteriales. This antibiotic is a cyclopropyl-polyene-pyran acid and is active in vitro against fungi.

A new oxisuran metabolite.

1. An unidentified oxisuran metabolite which had been observed in animal urine was biosynthesized by incubating [14C]oxisuran with rat liver cytosol. 2. The metabolite, isolated by preparative t.l.c. and extraction, was identified as oxisuran alcohol sulphide by mass fragmentography. Confirmation of this identification was obtained by biosynthesis of the same compound from oxisuran sulphide. 3. The 9000 g supernatant liquid from rat liver was less effective than cytosol in reducing oxisuran to its alcohol sulphide. Neither rat liver fraction reduced oxisuran alcohol sulphoxides to sulphide. 4. The 9000 g fraction oxidized oxisuran and oxisuran alcohol sulphoxide to oxisuran alcohol sulphone.

Metabolism of 3-(hydroxymethyl)-8-methoxychromone in the rat. II. Classification and identification of urinary drug metabolites.

1. Five metabolites were isolated from the urine of dogs dosed with 3-(hydroxymethyl)-8-methoxy[4-14C]chromone. These were identified as 8-methoxychromone, 2-hydroxy-3-methoxyacetophenone, 3-(hydroxymethyl)-8-hydroxychromone, 8-hydroxychromone and 2,3-dihydroxyacetophenone. 2. These compounds were also present in the urine of rats treated with labelled drug, together with unchanged drug and two intermediate metabolites, 3-carboxy-8-methoxychromone and 3-(carboxymethyl)-8-hydroxychromone. 3. In addition to the unconjugated labelled compounds, glucuronides and sulphates were identified. 4. Quantitative data were obtained for all of the 20 labelled compounds in rat urine. 5. A scheme is presented for the biotransformation of 3-(hydroxymethyl)-8-methoxychromone in rats and dogs, and a mechanism for scission of the gamma-pyrone ring is suggested.