P14.70 BMScope: A systematic mapping review of brain/leptomeningeal metastasis clinical studies from 2010 to 2020

BACKGROUND

Brain metastasis (BM) and leptomeningeal disease (LMD) are typified by a poor prognosis and are an area of unmet clinical need. Historically, patients with central nervous system (CNS) disease have been excluded from systemic therapy clinical trials, particularly with active/leptomeningeal disease. However, increasing prevalence of CNS metastasis is leading to greater interest in BM/LMD. We performed a descriptive analysis of clinical studies investigating BM/LMD management, published between Jan 2010 to Mar 2020.

METHODS

A comprehensive, customised search strategy was devised for 12 online bibliographic databases, using the following concepts: “clinical study”, “brain metastasis”, “leptomeningeal disease”, “intervention”, “patient-related outcome”. Double screening for inclusion/exclusion was performed on the Rayyan QCRI web application. Published abstracts were also screened for inclusion from ASCO, ESMO, SNO and EANO between 2015–2020. Following full text screening, conflicts were resolved by consensus and data were extracted using an online standardised tool. Data analysis and data visualisation were performed on the R statistical package.

RESULTS

Overall, 33118 published studies were double screened; 2632 full publications and 628 abstracts were included. Of these, 14.7% reported on unique interventional clinical trials (phase 2 = 267; phase 3 = 80). More than three times the number of clinical trials investigating systemic agents as the sole therapy for BM/LMD were published in Q1 2020 compared to the whole of 2010 (16 vs 5). 42.5% of clinical trials employed a form of local therapy (brain targeted radiotherapy or neurosurgery). Studies reported on patients with BM (n = 2738), LMD (n = 110) or both (n = 119). The majority of studies were performed in North America, Europe or East Asia (88.5% vs 11.5% rest of the world). The top 3 nations involved in published studies were the USA (n = 1155), China (n = 351) and Germany (n = 334). Network analysis demonstrated increasing links between countries. In line with expected BM prevalence, the main tumour sites studied were lung (23.4%), gastrointestinal (17.5%), breast (15%) and melanoma (12.5%). A rising trend of published BM/LMD studies over time was noted, with 83 observational studies/10 clinical trials in 2010 vs. 454 observational studies/80 clinical trials in 2019.

CONCLUSION

These findings demonstrate that over the last decade there has been a growth in BM/LMD research; likely reflecting an increasing disease prevalence, availability of novel and potentially CNS active agents, as well as more advanced local therapy modalities. BM/LMD clinical research is dominated by a few geographical regions and nations; however, there is an apparent shift to more international collaboration. This comprehensive mapping exercise will enable targeted systematic reviews of the existing evidence base on BM/LMD management.

Following anterior resection for rectal cancer, defunctioning ileostomy closure may be significantly delayed by adjuvant chemotherapy: a retrospective study

OBJECTIVE

A temporary loop ileostomy is often created to minimize the impact of peritoneal sepsis from an anastomotic dehiscence following colo-anal or low colorectal anastomosis. These stomas are not without complications. Clinicians tend to advise patients that their loop ileostomy will be reversed within 6-12 weeks of formation. However, factors such as adjuvant chemotherapy may affect the timing of closure. The aim of this study was to review the time between formation and closure of loop ileostomies following total mesorectal excision in patients with rectal cancer.

METHOD

A retrospective study of 50 patients with loop ileostomies to defunction total mesorectal excisions for rectal cancer, between April 2002 and July 2005.

RESULTS

Of the 50 patients with defunctioning loop ileostomies, 24 received adjuvant chemo-radiotherapy, and 26 did not. There was a 28% morbidity. The overall median time from formation to closure was 142 days (35-575). Median time from formation to closure in those with adjuvant therapy was 197 days (35-575) and in those with no adjuvant therapy was 133 days (75-395). This was a significant delay (P = 0.049). Sixteen stomas were not closed to date.

CONCLUSION

Time between formation and closure of loop ileostomy following anterior resection of rectum is significantly delayed by adjuvant chemotherapy. Because of their high morbidity, defunctioning ileostomies should be closed as early as medically possible, especially if adjuvant chemotherapy is planned.

An unusual case of segmental clavicle fracture

Fracture of the clavicle is a common traumatic injury and comprises 4% of all fractures in adults. Amongst these, midshaft injuries account for the majority and medial fractures are uncommon. Whilst segmental fractures have been reported in the literature, concurrent lateral and medial injuries are very rare. These injuries are, therefore, susceptible to being missed, due to failure to look for a second injury after the initial diagnosis, and difficult X-ray interpretation around the area of the medial clavicle. The nature of segmental fractures can pose a difficult management problem for numerous reasons, and initial operative fixation is usually indicated. Early diagnosis is therefore imperative, and as such, clinical examination is essential even if an obvious mid or lateral shaft fracture is seen on X-ray. This unusual case of combined lateral and medial fractures was initially missed and the presentation and management is discussed.

Development of an improved analytical method for the determination of carcinogenic polycyclic aromatic hydrocarbons in transformer oil

Polynuclear aromatic hydrocarbons (PAHs) are natural constituents of transformer oils and are essential in prolonging transformer in-service lifetime. Issues concerning PAH carcinogenicity demand methods that provide qualitative and quantitative information on the PAH composition of new and in-service oils to allow informed operational decisions to be made. However, current analytical methods focus on PAH fingerprinting, as opposed to quantitative analysis and are also cumbersome, relying on the use of large (>100 ml) volumes of organic solvents, some of which are hazardous. This paper reports a method for the improved quantification of carcinogenic PAHs in transformer oils that is both simple and repeatable. The method uses commercially available solid-phase extraction columns and millilitre volumes of relatively non-hazardous solvents. Extraction efficiencies of > or =74% were obtained for the Environmental Protection Agency priority PAHs. The method has potential for automation and high-throughput analysis and thus is of interest to industries that use transformer oils.

Quantification of polynuclear aromatic hydrocarbons in transformer oils by enzyme immunoassay

Many polynuclear aromatic hydrocarbons (PAHs) are either known or suspected carcinogens and are a common constituent of mineral oils. Due to the large number of possible PAH structures, standard quantification methods fail since they either lack specificity or are too complex, requiring individual fractionation, identification, and quantification. A rapid, low-cost, novel analytical screening method, incorporating a silica-based solid-phase extraction (SPE) method linked to co-solvent dilution and quantification of total and carcinogenic PAH levels by immunoassay, is reported here. The method yielded high extraction efficiencies and minimal matrix effects. This novel approach yielded total and carcinogenic PAH levels x 5.7 and x 126, respectively, lower than that recorded by the industry-recognised BS2000 Pt. 346 (IP346) method which estimates the polyaromatic carbon (PAC) content of oils by gravimetry. The method is expected to be of benefit where an indication of PAH levels in oils is important for purchasing, management or disposal purposes and also for risk assessment and for appropriate labelling of oils in line with current legislation.

Prospects for reducing and refining the use of dogs in the regulatory toxicity testing of pharmaceuticals

A workshop was held to critically discuss the need for a nonrodent species and the role of the dog in regulatory toxicity testing of pharmaceuticals; to discuss opportunities to reduce and refine the use of dogs in preclinical toxicology; and to identify a number of specific recommendations which could be feasibly achieved to move the process forward. To facilitate a preliminary evaluation of the contribution of dog studies to the risk assessment process, anonymised, unpublished data were provided from fully evaluated, repeat-dose toxicity studies in the rat and dog. Results of the International Life Sciences Institute (ILSI) Human Toxicity Project were also presented and discussed. Analysis of the data demonstrated that the dog can provide additional toxicity information, which, in some cases, was shown to be predictive for humans. Discussions indicated that there is potential for achieving a reduction in dog use and several possible approaches were identified. To further the progress of this initiative, there is a need to collate the results of pharmacology, toxicology, and clinical studies to address some of the proposed approaches. One of the outcomes of the workshop will be the establishment of a steering group to co-ordinate data collation for further analysis.

CD34+AC133+ cells isolated from cord blood are highly enriched in long-term culture-initiating cells, NOD/SCID-repopulating cells and dendritic cell progenitors

The AC133 antigen is a novel antigen selectively expressed on a subset of CD34+ cells in human fetal liver, bone marrow, and blood as demonstrated by flow cytometric analyses. In this study, we have further assessed the expression of AC133 on CD34+ cells in hemopoietic samples and found that there was a highly significant difference between normal bone marrow and cord blood versus aphereses (p <0.0001) but not between bone marrow and cord blood. Most of the clonogenic cells (67%) were contained in the CD34+AC133+ fraction. Compared with cultures of the CD34+AC133- cells, generation of progenitor cells in long-term culture on bone marrow stroma was consistently 10- to 100-fold higher in cultures initiated with CD34+AC133+ cells and was maintained for the 8-10 weeks of culture. Only the CD34+AC133+ cells were capable of repopulating NOD/SCID mice. Human cells were detectable as early as day 20, with increased levels (67%) apparent 40 days post-transplantation. Five thousand CD34+AC133+ cells engrafted about 20% of the mice, while no engraftment was observed in animals transplanted with up to 1.2 x 10(5) CD34+AC133- cells. The CD34+AC133+ population was also enriched (seven-fold) in dendritic cell precursors, and the dendritic cells generated were functionally active in a mixed lymphocyte reaction assay. AC133+ cells should be useful in the study of cellular and molecular mechanisms regulating primitive hemopoietic cells.

Induction of chromosome aberrations in peripheral blood lymphocytes after short time inhalation of nitric oxide

INTRODUCTION

inhalation of nitric oxide (INO) leads to vasodilation of pulmonary vasculature in ventilated regions of the lung. The clinical use of INO, although not formally approved as a drug, is widespread. NO may rapidly form nitrogen dioxide (NO2) in an oxygen containing gas mixture. NO2 has been shown to induce chromosome aberrations and mutations in both animal and bacterial test systems. We investigated whether a 2-h exposure to NO would increase frequencies of cells with chromosome aberrations in peripheral blood lymphocytes of human volunteers.

METHODS

10 volunteers were exposed to inhaled NO 40 parts per million (ppm) for 2 h. Pre- and post-exposure blood samples were analysed.

RESULTS

no statistically significant differences (p</=0.05) in chromosome aberrations were observed between pre- and post-exposure samples.

CONCLUSION

no detectable increase of chromosome aberrations in human peripheral blood lymphocytes after 2 h of NO-inhalation 40 ppm was found.

Toxicological requirements for sclerosing agents or other chemicals for female sterilization

There are no guidelines regulating the technologies available for Fallopian tube occlusion. Generally accepted regulatory requirements cannot be applied directly to the safety assessment of these technologies. The more appropriate guidelines are those regulating medical devices. Each method has to be evaluated on its own merits taking into consideration the duration of contact with tissue and the chemical and physical composition of the occlusive agents.

Carcinogenicity assessment of lonidamine by dietary administration to Sprague-Dawley rats

Following chronic dietary administration of 20, 60 and 180 mg/kg per day of lonidamine for 2 years to groups of Sprague-Dawley rats, treatment-related non-tumour findings seen microscopically included the following: atrophy of the testis with associated changes in epididymis and pituitary at all dosages; neuropathy in the sciatic nerve accompanied by skeletal muscle atrophy which was dose-related, particularly in male animals. Neither the incidence of tumour-bearing animals, nor the spectrum of tumours seen, was significantly changed. In the females given 180 mg/kg per day an overall reduction in tumour incidence was noted, which was reflected in a significant reduction (P < 0.001) in mammary tumours.

Age-related changes in thyroid structure and function in Sprague-Dawley rats

Investigation of thyroid glands from 500 male and 500 female Sprague-Dawley rats, at time points of 8, 17, 30, 56, and 108 weeks of toxicity studies conducted at the Huntingdon Research Centre between 1981 and 1984, revealed age-related structural and functional changes that have previously not been well documented. The number of ultimobranchial cysts decreased with age, while area(s) of C-cell hyperplasia appeared with age. Beginning at 56 weeks, some of the thyroid follicles were hyperdistended with colloid, had irregular lumens, and were lined by flattened epithelium. These follicles had clumped, granular, and stratified colloid. Follicular tumors were found in 8% of the males and 6% of the females at 108 weeks. There was an increase in absolute thyroid weights (males from 21.8 +/- 4.0 g to 46.5 +/- 19.05 g, females from 17.2 +/- 4.53 g to 41.7 +/- 26.92 g) and body weights (males from 382.0 +/- 70.6 g to 806.0 +/- 120.7 g, females from 220.0 +/- 21.0 g to 495.0 +/- 127.3 g) with age in both sexes, but the relative thyroid weights were not significantly affected. Negative allometry was observed. With an increase in the age of the rats, there was a decrease in the height of the follicular epithelium and an increase in the internal follicular diameter and the total number of follicles. No prediction for sex could be detected. Serum T3 and T4 concentrations were constant until 56 weeks of age, but at 108 weeks, the values were markedly reduced (in males, serum T3 concentration decreased from 91.60 +/- 13.970 ng/100 ml to 32.90 +/- 10.878 ng/100 ml, and in females, from 90.80 +/- 11.338 ng/100 ml to 48.10 +/- 8.875 ng/100 ml; in males, serum T4 concentration decreased from 5.94 +/- 0.679 microgram/100 ml to 3.04 +/- 0.604 microgram/100 ml, and in females, from 4.59 +/- 0.717 microgram/100 ml to 2.77 +/- 0.786 microgram/100 ml). The data suggest that the thyroid function of Sprague-Dawley rats reduces as the rats age.

Morphological assessment of visual dysfunction

The eye is an isolated unit but with a potentially high degree of sensitivity to toxic substances. The multiplicity of types of reaction to injury reflects the unique anatomical, physiological and biochemical features of the eye. The following are examples of such: The albino rat is not a good model for retinal toxicity because of problems of phototoxic retinopathy, the absence of pigment within the pigment epithelial layer and the high incidence of spontaneous retinal pathologies; The ocular toxicity of a compound cannot be anticipated from its chemical structure; Pharmacological side effects are similar between species, and are predictive for man; Mechanisms of ocular toxicity are poorly understood.

Toxicity studies with quinine hydrochloride

Three-month studies in the rat, a rat embryo-toxicity study and a specific study to investigate ototoxicity were carried out with quinine hydrochloride. The results of these studies suggest an acceptable daily intake of 40 mg quinine hydrochloride for an adult. There were no indications of teratogenic effects and no indications of interference with auditory function in rats receiving up to 200 mg/kg.

The toxicology of gossypol acetic acid and (-)-gossypol

The toxicity of gossypol has been investigated in Sprague-Dawley rats at dosages of 0, 0.5, 5.0 and 25 mg/kg per day of (+/-)-gossypol acetic acid. The most significant toxicological finding was marked suppression of body weight gain in rats receiving 25 mg/kg per day. Terminal studies showed 6 out of 20 rats receiving 25 mg/kg per day to have varying degrees of testicular pathology. Five mg/kg per day was shown to be a "no effect" level. A study in cynomolgus monkeys at 25 mg/kg per day of (+/-)-gossypol acetic acid for 13 weeks induced death, a variety of clinical signs, extensive biochemical change and pathology in the heart, liver, kidney and testes. The toxicity of (-)-gossypol was investigated in male cynomolgus monkeys at dosages of 1.5, 4 or 5 mg/kg/day for 4 weeks. No animals died. Clinical signs involving the gastrointestinal tract, adverse effects on body weight gain, consistent biochemical changes in serum proteins, calcium, inorganic phosphorus and serum cholesterol were recorded at 4 mg/kg per day and above. Morphological change was not induced.

A report on drug-induced kerato-conjunctivitis sicca in dogs

Kerato-conjunctivitis sicca is reported in beagle dogs treated with an antispasmodic compound for 26 weeks during a routine toxicity study. There was a deficiency of lachrymal secretion associated with keratitis and corneal vascularization. Histopathologically, the changes were characterized by vascularization, fibroblast proliferation and infiltration of inflammatory cells in the substantia propria. In some cases, the inflammation also occurred in corneal epithelium, ocular conjunctiva and corneal limbi.

The toxicity of gossypol to the male rat

When (+/-) gossypol acetic acid was administered to male Sprague-Dawley rats for 26 weeks, the most significant toxicological finding was marked suppression of body weight gain in rats receiving 25 mg/kg per day. Minor biochemical changes were noted at this dosage level. Terminal studies showed 6 out of 20 rats receiving 25 mg/kg per day to have varying degrees of testicular pathology. Five mg/kg per day was shown to be a "no effect" level.

Animal models: their use and limitations in long-term safety evaluation of fertility-regulating agents

Animal studies are usually to predict the value of new compounds and to assess their incorporation into schemes to reduce or clarify recognized hazards. There are two assumptions, that animal models are appropriate and dose-response relationship can be derived. Such tests cannot provide definite evidence about the safety of such medical agents in man. Examples are given of data arising from studies of progestogens or oestrogens in animals in relation to clinical conditions. The scientific quality of these tests depends on the adequacy of an appropriate design, competent staff and a correct evaluation of the results.

Strain-related susceptibility to nephrotoxicity induced by aspirin and phenylbutazone in rats

Single doses of aspirin induce scattered foci of necrosis of proximal tubules in some strains of rats, whereas acute or sub-acute administration of phenylbutazone causes renal papillary necrosis. Initially, using Sprague-Dawley rats of CFY and CD strains, it became clear that these rats were not as susceptible to these drugs as the literature suggested. Aspirin-induced necrosis was apparently sex-related, being seen in females but could be induced by hormone treatment in males. Male Wistar and Sprague-Dawley rats had reacted differently to administration of phenylbutazone for two weeks. Two experiments were performed with four rat strains: Wistar, Lister-Hooded, Sprague-Dawley, and Fischer-344. The rats were six weeks old at the start of the experiments. Five males and five females of each strain were gavaged with either a single dose of 1,000 mg/kg of aspirin or 200 mg/kg phenylbutazone once daily for four weeks. The drugs were suspended in methylcellulose, which was given to equal numbers of control male and female rats in each experiment. The rats were maintained under standard conditions. Blood and 18-hour overnight urine samples were collected prior to sacrifice. There were no strain-related differences in the types of renal lesions seen, however there were differences in the degrees of responses to the two drugs. With aspirin the female Fischer-344 rats were the most susceptible showing necrosis of proximal tubules of both kidneys and markedly elevated urinary protein concentration and gamma-GT activity. Other females showed less change. Male rats were affected only slightly and males of the Wistar strain were not.(ABSTRACT TRUNCATED AT 250 WORDS)

Age-related variations in renal structure and function in Sprague-Dawley rats

Data from 500 male and 500 female Sprague-Dawley rats used as controls in studies performed at Huntingdon Research Centre to assess the safety of drugs were sampled at 17, 30, 56, 82, or 108 weeks of age. Plasma urea nitrogen levels remained constant, except in aged males. Aging caused increased proteinuria and decreased urinary concentrating ability, in addition to increased size, weight, and degree of cortical scarring of kidneys. Chronic progressive nephropathy, first seen histopathologically at 30 weeks of age, accounted for these changes and ultimately affected 81% of male and 44% of female rats. One-fifth of two-year-old male rats had diffuse parenchymal damage and a small number also had secondary hyperparathyroidism. Other notable changes included basophilic (often colloid-filled) cortical tubules, mononuclear cell infiltrations, parenchymal and pelvic mineralization, urothelial hyperplasia, and pyelonephritis. Miscellaneous low incidence findings included one lipomatous tumour and generalized lymphosarcoma.

The toxicity of beta-carotene

The safety of beta-carotene, a widely distributed food colorant was assessed in tests with cells and in sub-chronic and chronic experiments with animals. Mutagenicity evaluations which included the standard Ames test and the micro-nucleus test of bone marrow cells from mice showed that beta-carotene exerted no mutagenic properties. Embryotoxicity studies in rats and rabbits showed that there was no evidence of embryotoxicity and a multiple generation study in rats showed that there was no interference with the reproductive function in rats given oral doses of up to 1000 mg/kg/day. Chronic toxicity was studied in a 2-year study with dogs in a toxicity/tumorigenicity study in rats and in a mouse carcinogenicity study. Histological findings in the livers of treated dogs and mice, but not in rats, included vacuolated cells with eccentric nuclei which were distributed in periportal areas and which were frequently associated with minimal lipid deposition. There was no evidence that the vacuolisation was dose-related. It was considered that the vacuolated cells were fat storage cells. There was no effect on the tumor profiles in the rat and the mouse studies.

Tumorigenic and toxic effect of O,S-dibenzoyl thiamine hydrochloride in prolonged dietary administration to rats

The chronic toxicity of O,S-dibenzoyl thiamine hydrochloride (DBT) was studied by prolonged dietary administration to rats at dosages of 1000 and 10 000 ppm. The study confirmed the low toxicity of this compound and absence of carcinogenicity.

Age-related susceptibility to aspirin-induced nephrotoxicity in female rats

The effect of puberty on aspirin-induced renal necrosis in female Sprague-Dawley rats was observed. Rats aged 31 days were unaffected by aspirin administration, but 55-day-old rats showed segmental cortical tubular necrosis after a single dose of 1000 mg/kg of aspirin. Urinary gamma-glutamyl transpeptidase (gamma-GT) and proteinuria were useful non-invasive indicators of these necrotic changes.

Target organ toxicity II

Sensitive criteria of toxicity are simple characteristics, such as growth, organ weight analysis and selected histopathological examinations. Appropriate laboratory tests support the clinical observations. Correlation of target organ toxicity across the species is poor.

Phenylbutazone-induced nephrotoxicity in the rat

Male Wistar rats showed reduced urinary concentrating ability after 2 weeks' administration of phenylbutazone at 200 mg/kg/day. Male Sprague-Dawley rats showed progressive proteinuria and developed renal papillary necrosis when given phenylbutazone at 200 mg/kg/day for 13 weeks. It is suggested that strain differences exist in the nephrotoxic profiles of rats given high doses of phenylbutazone.

The toxicology of a ganglioside extract (Cronassial)

The accepted animal toxicity studies indicate that the ganglioside mixture extracted and purified from the bovine brain cortex (Cronassial) is without detectable toxicity. It did not induce any adverse effects on any of the characteristics of reproduction and it is not antigenic.

Toxicity of venalot (a mixture of coumarin and troxerutin) in the baboon

Venalot, a mixture of coumarin and troxerutin, in the proportion 1 to 6 respectively, was given orally to baboons at dosages of 0, 100, 300 and 1000 mg/kg/day for 26 weeks. Vomiting, usually within 3 h of administration and considered to be of central origin, in addition to vomiting immediately after dosing, was noted in animals receiving 1000 mg/kg/day. At this level, collapse on several occasions in two animals, one of which died, was also observed. Another animal receiving 1000 mg/kg/day was killed for humane reasons following a period of weight loss, reduced appetite and deterioration in body condition. However, no adverse effect on body weight gain, food or water consumption, ophthalmoscopic or electrocardiographic examinations were noted in any other animals during this study. Increased levels of liver function (serum leucine amino-peptidase (LAP), and serum ornithine carbamyl transferase (OCT) were noted during the dosing period, together with slightly increased liver weights terminally for animals receiving 1000 mg/kg/day; however, as no morphological or ultrastructural changes were noted, these findings were considered to be attributable to hypertrophy.

Histopathological and laboratory assessment of visual dysfunction

The currently available methods of assessing ocular toxicity are discussed. Manifestations of ocular toxicity are best described clinically; histopathological examination of the eye is beset with problems of preparing the eye for morphological examinations. Electron microscopy is essential to look for chemically induced side effects at the cellular level. Mechanisms of ocular toxicity are poorly understood, and the limitation of animal studies in predicting side effects in man must be appreciated.

The LD50 test: some considerations of precision

Substantial improvements in the statistical aspects of the LD50 test are possible. These include modifications to the design of the experiments (including the use of sequential methods) and the replacement of outdated techniques of statistical analysis with more appropriate methods. With such improvements, it would be possible to reduce appreciably the number of animals used (to about 10 or 12) while still achieving precision similar to that obtained with present methods.

Sub-acute toxicity studies on a new piperidine derivative (HSR-902) in dogs

The administration of a new piperidine antispasmodic agent (HSR-902) to the dog by the oral and intravenous routes, induced clinical signs attributable to parasympathetic blockage. The only significant toxicological finding was rarefied appearance and enlargement of the hepatocytes at the high dose level (50 mg/kg/day); this was shown to be reversible.

Chronic intravenous administration of lentinan to the rhesus monkey

The prolonged effects of overdosage with lentinan in the rhesus monkey are associated with foam cell reactions in lung, liver, kidney, spleen, lymph nodes and bone marrow and with varying degrees of vasculitis and associated reactions. A dose level of 0.5 mg/kg/day was without adverse effect.

The intravenous toxicity of lentinan to the beagle dog

The i.v administration of lentinan to the Beagle dog induced changes in the cytoplasm of macrophagic cells in the liver, spleen, kidney, lungs, lymph nodes, small intestine. Electron-lucent or filamentous inclusions were demonstrated in the liver, kidney and spleen. A dose level of 0.5 mg/kg/day was without adverse effect.

Target organ toxicity

In a survey of the toxicological profiles of 50 compounds in rodent and non-rodent species, sensitive criteria of toxicity were found to be the simple characteristics, such as clinical observation of the living animal, growth and organ weight analysis, liver and kidney function tests and histological examination of selected tissues. There was poor correlation of target organ toxicity across the species. For this reason safety evaluation should not be based on the demonstration of target organ toxicity, but on the absence of toxic signs. A step by step approach, based on the biological activity of the compound, would provide more meaningful data for safety evaluation than the standard toxicological studies in a rodent and non-rodent species.

Effects of morphine sulphate on pituitary-testicular morphology of rats

Morphine sulphate was administered, buy s.c. injection, to male rats at 50 mg/kg/day for up to 9 weeks. Control rats were given s.c. injections of sterile water. Serum luteinising hormone (LH) and testosterone concentrations and the weight and morphology of testes, pituitary glands and secondary sex organs were examined after 4 and 9 weeks' morphine treatment and also 13 weeks after dosing stopped. Treatment with morphine decreased serum LH and testosterone concentrations and reduced secondary sex organ weights. Differential staining techniques revealed modified secretory activity of pituitary gonadotrophic cells. All stages of spermatogenesis were found in testicular sections, but quantitative reductions in spermatogenic cell populations were found among morphine-treated rats. All the observed effects were reversed within 13 weeks of drug withdrawal. These findings are discussed in relation to existing knowledge of the hormonal control of spermatogenesis in rats.

The ultrastructural features of progestagen-induced decidual cells in the rhesus monkey (Macaca mulatta)

Five rhesus monkeys were treated with levonorgestrel-releasing intravaginal rings for 52 weeks. The rings were designed to provide a sustained release of ten times the human dose level of the hormone. Histological examination of the uterine endometrium showed widespread decidualisation of endometrial stromal cells. Ultrastructurally, two distinct cell types were identified: decidual and granular. Some of the decidual cells were ultrastructurally comparable with those reported elsewhere; however, in aproportion of these cells, intracisternal sequestration of the rough endoplasmic reticulum was widespread. The granular cells resembled those described in the metrial gland of rats and, as their name suggests, contained variable numbers of electron-dense granules.

The intravenous toxicity of dibekacin sulphate (DKB) to female beagle dogs

Dibekacin sulphate (DKB), a new aminoglycoside antibiotic developed on the theory of bacterial resistance, was given by intravenous injection to groups of female Beagle dogs at dosages of 2.5, 5.0, 10.0 or 25.0 mg/kg/day for 13 weeks. Physiological saline was given as a control. Some dogs given 5.0 or 10.0 mg/kg/day were retained undosed for a further 5 weeks in order to assess recovery. Premature deaths from acute renal tubular nephrosis occurred in dogs given 25.0 and 10.0 mg/kg/day. Dogs which survived treatment at 10.0 mg/kg/day showed marked elevation of circulating urea and creatinine concentrations after 4 weeks' treatment but thereafter the increases became less obvious. Varying degrees of renal cortical tubular dilatation, basophilia, degeneration or necrosis were seen in the kidneys of all dogs examined after 13 weeks treatment although no clinical impairment of renal function was detectable at dosages up to 5.0 mg/kg/day. These changes had essentially regressed in dogs examined 5 weeks after the last dose of DKB at 5.0 mg/kg/day. All the adverse clinical and histological effects noted, following any dose level of DKB tested, could be attributed to renal changes.

Quantitative assessment of spermatogenesis in rats given 1-amino-3 chloro-2 propanol hydrochloride (CL 88, 236)

A quantitative histomorphometric assessment of testicular spermatogenesis was undertaken on testes from rats which had received 1-amino-3 chloro-2 propanol hydrochloride (CL 88, 236) at oral doses of 0, 50, 250 or 500 mg/kg/day for 12 weeks. Rats which developed epididymal sperm granulomata or severe atrophy of the germinal epithelium were excluded from quantitative examination. Pathological changes in the epididymis and semininferous epithelium were not strongly correlated. CL 88, 236 administered at 50 mg/kg/day was without effect on the histomorphometry of the seminiferous epithelium, although epididymal lesions occurred at this dose. At higher doses a quantitative reduction in testicular spermatids was evident. It appears important to differentiate between the selective antifertility action of CL 88, 236 on the biochemistry of epididymal spermatozoa and the disruption of epididymal physiology, and testicular spermatogenesis found at unusually high doses.

Quantitative aspects of spermatogenesis in rats and dogs after repeated hexachlorophene treatment

Hexachlorophene was administered orally, at subneurotoxic doses, to rats (5 mg/kg/day) and dogs (3 mg/kg/day) for 9 weeks: some of the rats and dogs were observed for a further 13 weeks. The serum concentrations of pituitary gonadotrophin and testosterone were unaffected in either species. No changes were induced in the testicular dimensions or semen characteristics of dogs and no macroscopic post mortem abnormalities, organ weight differences or lesions detectable by conventional light microscopy were found in their testes, pituitaries or secondary sex organs. A transient reduction in the number of germ cells counted in cross-sections of seminiferous tubules was seen in rats after 4 weeks treatment. After 9 weeks treatment, reduced spermatogonial counts were recorded in canine seminiferous tubules; in other respects spermatogenesis was proceeding normally. No delayed effects were apparent in eith species. It is concluded that repeated administration of hexachlorophene at subneurotoxic levels did not induce significant impairment of spermatogenesis in rats or dogs.

Renal toxicity of aspirin to rats pre-treated with ethinyl oestradiol

Castrated rats receiving aspirin at a dose level of 1000 mg/kg showed necrosis of the proximal convoluted tubules, similar to that seen in female rats, and the extent of this lesion was increased by oestrogen pre-treatment. Urinary gamma-glutamyl transpeptidase activity was a useful indicator of the necrotic changes induced.