Naphthalimido derivatives as antifolate thymidylate synthase inhibitors

A new series of N-(substituted)benzyl-1,8-naphthalimides 4, structurally related to the previously reported thymidylate synthase (TS) inhibitor naphthaleins 3, were synthesized and compounds tested for their inhibition of several species of TS. Moreover, their in vitro cytotoxicity together with antimycotic and antibacterial properties were assayed. While no activity was detected in the antibacterial tests, the m-nitro (4ae) and the p-nitro (4af) derivatives were found able to partially inhibit TS at low micromolar concentrations. Introduction of nitro or (substituted)-amino groups in position 4 of the naphthalic ring always led to less active compounds.     

Feeding microstructure in diet-induced obesity susceptible versus resistant rats: central effects of urocortin 2

With one billion people overweight worldwide, the need to identify risk factors and treatments for obesity is urgent. The present study determined whether rats genetically prone to diet-induced obesity (DIO) show preexisting differences in meal microstructure and are sensitive to central anorectic effects of corticotropin-releasing factor type 2 (CRF₂) receptor stimulation. Male, selectively bred DIO rats and their diet resistant (DR) counterparts ( n = 9/genotype) were weaned onto low-fat chow and compared as young adults for spontaneous or intracerebroventricular urocortin 2 administration-induced (0, 0.3, 1, 3 μg) differences in ingestion. DIO rats were hyperphagic selectively at the dark cycle onset, showing shorter latencies to initiate feeding, faster returns to eating following meal completion, and a lower satiety ratio than DR rats. At other times, DIO rats had briefer postmeal intervals, but ate smaller and briefer meals, resulting in normal intake. DIO rats also ate faster than DR rats. Urocortin 2 was less potent in DIO rats, ineffective at the 0.3 μg dose, but produced CRF₂ antagonist-reversible anorexia at higher doses. Though heavier, chow-maintained DIO rats were proportionately as or more lean than DR rats. Thus, DIO rats showed signs of a preexisting, heritable deficit in the maintenance of postmeal satiety and a reduced sensitivity to anorectic CRF₂ agonist stimulation. The meal patterns of DIO rats temporally resemble human 'snacking' behaviour, which predicts adult obesity. Because central CRF₂ stimulation retains full anorectic efficacy at higher doses in the DIO model, manipulating this neuropeptidergic system might yield new therapeutic approaches for diet-induced obesity.     

Critical ovarian hyperstimulation syndrome in a coasted in-vitro fertilization patient

We report an instance of critical ovarian hyperstimulation syndrome in a highly responsive in-vitro fertilization patient despite the preventive measure of a 4 day 'coast' interval during which no gonadotrophins were administered while gonadotrophin-releasing hormone agonist therapy continued until serum oestradiol concentrations fell below 3000 pg/ml.      

METHYLATION STATUS OF BCL6 DISTINGUISHES DNA SAMPLES FROM BENIGN AND MALIGNANT LYMPHOPROLIFERATIVE DISORDERS

INTRODUCTION: Core biopsy of the breast has become the method of choice for tissue diagnosis of screen detected microcalcifications and some mass lesions in many breast assessment centres. Biopsy results are not available until the following day. Imprint cytology of fresh breast core samples allows same-day reporting and patient counselling.
AIM: To determine the accuracy of core imprint cytology when compared with core biopsy diagnosis when used in a breast assessment centre setting.
METHODS: Core imprints (CI) were prepared and reported on all fresh core biopsies (CB) performed at the Sir Charles Gairdner Hospital Breast Centre from May to December 2000. Fresh core samples were placed on a glass microscope slide. Core radiographs were taken for microcalcification lesions (MC). A laboratory technician gently and quickly rolled the cores on the slide with fine forceps. The cores were fixed in formalin, processed and reported next day. The imprint slide was air dried and stained with DiffQuik. CI were reported using four categories: Insufficient, Benign, Indeterminate and Malignant. Counselling and planning for management were possible on the same day in women with malignant diagnoses. Clinicians were advised not to discuss negative or indeterminate CI results with women and to defer to the final CB report.
RESULTS: Cores were performed on 381 lesions. There were 83 carcinomas (38 in MC and 45 in masses) and 56 were called malignant on CI (absolute sensitivity 67.5%; 78.9% for MC and 57.8% for masses). 3 malignancies on CB were negative on CI giving a false negative rate of 3.6%. There were no false positive diagnoses. The predictive value of a benign diagnosis was 95.3%. There were no adverse effects in the histology of CB.
CONCLUSION: CI was an accurate method of providing an immediate diagnosis of malignancy in two thirds of malignancies confirmed on CB.     

Serotonin-depleting midbrain lesions fail to mitigate hyperphagia and obesity in the Zucker fatty rat

Previous research has shown that damage to the dorsal and median raphe nuclei of rats can impede the subsequent development of hypothalamic hyperphagia and obesity as well as impair the defense of established hypothalamic obesity in response to food deprivation. The present study sought to determine if raphe injury might alter the development of another form of obesity, namely that which occurs spontaneously in the Zucker fatty rat. Subjects were 20 obese females (fafa; mean weight of 200 g) and 20 lean littermate controls (FaFa females; mean weight of 150 g). Following 10 days of baseline intake and weight recordings, half of each group received radio-frequency heat lesions of the dorsal and median raphe nuclei while the other half received sham surgery. Except for a mild suppression of food intake and weight gain during the first few days after lesioning, raphe injury did not alter the hyperphagia or obesity shown by fatties over the 7 week ad lib feeding period studied. Additional 24-hr intake tests of varying sucrose and quinine solutions revealed reduced sucrose acceptance and enhanced quinine rejection by fatties much as has been seen in previous studies of hypothalamic obese rats. Terminal assays of forebrain monoamine levels confirmed that raphe lesions were effective in depleting serotonin (-71% compared to controls) without producing major changes in norepinephrine or dopamine (-14% and +2%, respectively). The inability of raphe lesions to mitigate this form of hyperphagia and obesity suggests that earlier observations of their attenuating effects on hypothalamic obesity were not due to non-specific impairments of behavioral or metabolic factors necessary to permit overeating and weight gain.     

Is there a non-dopaminergic nigrostriatal pathway?

Sixteen per cent of the substantia nigra cell bodies normally labeled from the injection of a fluorescent retrograde tracer in the caudate-putamen complex could still be labeled by the same procedure after multiple intracisternal 6-hydroxydopamine treatments that depleted dopamine levels in the caudate-putamen complex to 1.0% of control. However, the demonstration of glyoxylic-acid-induced catecholamine histofluorescence in tissue from these lesioned rats revealed that many of the surviving retrogradely-labeled substantia nigra cell bodies still contained dopamine. The persistence of some dopamine in the substantia nigra of the lesioned animals was confirmed biochemically. Therefore, retrograde tracing in 6-hydroxydopamine lesioned rats overestimated the extent of the non-dopaminergic nigrostriatal tract.The simultaneous combination of retrograde fluorescent tracing and catecholamine histofluorescence in unlesioned animals revealed that only 5% or less of the substantia nigra cell bodies retrogradelylabeled from the caudate-putamen complex were without catecholamine fluorescence. These apparently non-dopaminergic nigrostriatal cells were located primarily in the ventral tegmental area, substantia nigra pars reticulata and extreme medial edge of the substantia nigra pars compacta.     

Impaired diet-induced thermogenesis in brown adipose tissue from rats made obese with parasagittal hypothalamic knife-cuts

Two experiments were performed to determine if bilateral parasagittal hypothalamic knife-cuts (KCs), which produce long-term overeating and obesity, after biochemical indices of brown adipose tissue (BAT) reactivity to thermogenic stimuli. In the first study, responses to environmental cold were tested. Four weeks after surgery, KC rats had gained 4-5 times more weight than controls and were obese (increased Lee Obesity Index and weight of gonadal white fat). Before being sacrificed, groups of KC and control rats were exposed to 4 degrees C for 21 hr or remained at 28 degrees C. Interscapular BAT weighed 300% more in KC rats, due largely to increased white fat content. Functional indices of BAT thermogenic capacity (protein content, DNA content, cytochrome oxidase activity and mitochondrial guanosine diphosphate (GDP) binding) were normal at 28 degrees C. Exposure to 4 degrees C produced greatly enhanced responses but these were equivalent for both groups. This suggested an intact capacity for non-shivering thermogenesis in obese KC rats. In the second study, the same BAT responses were examined in other rats fed a palatable "cafeteria" diet (CAFE). One week after surgery, KC and control rats were subdivided into groups that received chow alone or chow plus four different palatable foods daily. Before sacrificing 4-5 weeks later, KC rats had gained 3-4 times more weight than controls and were obese. Interscapular BAT weighed 200-300% more in KC rats. CAFE feeding produced larger increments in all variables for KC vs. control rats. Most importantly, GDP binding was reduced in both KC groups, and significantly more so after CAFE feeding.(ABSTRACT TRUNCATED AT 250 WORDS)