A Short-Term Chemosensitivity Test with Different Labeled Precursors of DNA or Protein Synthesis: Correlation with Clinical Response

Blood or bone marrow samples from 15 patients with newly diagnosed acute myeloblastic leukemia undergoing remission induction treatment with daunorubicin, cytosine-arabinoside and 6-thioguanine were tested in vitro. Leukemic cells were incubated for 24 h at 37 °C with or without the drugs alone or in combination. A 3-h pulse with labelled precursors of DNA synthesis (3H-thymidine) or protein synthesis (3H-leucine) was then given separately. In vitro growth, expressed as the percentage ratio between labeled precursor uptake in treated cells and in control cells, was compared with the clinical results obtained. Three patients were not considered evaluable (death occurred too early), 8 had a complete response (CR), and 4 were disease resistant to chemotherapy. Leukemic cells of resistant-disease patients showed a significantly lower growth inhibition than cells taken from CR patients, with each drug alone or in combination, when measured with thymidine. Inhibition of leucine uptake was not related to the clinical outcome.

In primary neuronal cultures muscarinic m1 and m3 receptor mRNA levels are regulated by agonists, partial agonists and antagonists

The homologous regulation of the muscarinic m1 and m3 receptors mRNA was studied in rat corticostriatal neuronal cultures. In response to the full agonist carbachol the m1 and m3 receptor mRNA levels were modulated and showed different time-courses. The m1 receptor mRNA increased to 270% of prestimulation levels after 6 h, while the m3 receptor transcript transiently increased to 170% after 2 h. Conversely, the muscarinic receptor partial agonist oxotremorine caused a rapid and sustained increase in both mRNA species as soon as after 1 h of exposure. A comparable increase in both receptor mRNAs was induced by the partial agonist [4-(m-chlorophenylcarbamoyloxy)-2-butynyltrimethyl-ammonium chloride] (McN-A-343). The observation that 1 h exposure to the non selective antagonist N-methyl-scopolamine also enhanced the m1 and m3 receptor transcripts suggests that in corticostriatal neurons muscarinic receptor partial agonists exert an antagonist-like effect on the m1 and m3 receptor mRNAs.

Intracerebroventricular administration of nerve growth factor affects muscarinic cholinergic receptors in the cerebral cortex of neonatal rats

The repeated intracerebroventricular administration of nerve growth factor (5 micrograms/2.5 microliters) to neonatal rats induced the activation of choline acetyltransferase in forebrain cholinergic neurons that was paralleled by a concomitant change in the density of muscarinic cholinergic receptors in the cerebral cortex. The administration of nerve growth factor altered muscarinic binding sites in a biphasic fashion during postnatal development. A significant stimulation of the developmental increase in the density of muscarinic binding sites occurred in nerve growth factor-treated animals at days 2 and 3 after birth. Conversely, nerve growth factor induced a significant decrease in the receptor number at postnatal days 8 and 14. Muscarinic receptor number returned to control values after treatment, suggesting that nerve growth factor-induced changes to muscarinic cholinergic receptors are reversible. Nerve growth factor administration did not affect muscarinic cholinergic receptor density in striatal membranes and did not alter the relative content of cortical messenger RNAs encoding m1 and m3 muscarinic cholinergic receptor subtypes at postnatal day 14, as determined by reverse transcriptase-polymerase chain reaction. The up- and down-regulation of muscarinic cholinergic receptors induced by nerve growth factor during postnatal development may be temporally related events associated with concomitant changes in the activity of choline acetyltransferase.

The murine NPY-1 receptor gene. Structure and delineation of tissue-specific expression

The murine gene for the NPY-1 receptor subtype for neuropeptide Y was characterized by DNA sequencing and expression studies. It comprises three exons with a 6,400 bp 5'-untranslated and a 80 bp internal intronic sequence. The 5'-flanking region of this gene lacks TATA or CCAAT consensus sequences in the proximity to the multiple transcription initiation sites. A 1,300 bp genomic fragment of the 5'-flanking region drives the expression of the lacZ reporter gene in NG108-15 cells and primary cultured neurons but not in glial and human embryonic kidney cells. In addition, it contains consensus sequences for various transcription factors including cAMP- and glucocorticoid-responsive elements.

Nerve growth factor modulates the expression of muscarinic cholinergic receptor messenger RNA in telencephalic neuronal cultures from newborn rat brain

The effect of nerve growth factor (NGF) on muscarinic receptor subtypes was investigated in a primary culture of telencephalic neurons prepared from neonatal rats. The treatment with 100 ng/ml of NGF significantly enhanced choline acetyltransferase (ChAT) activity and intracellular acetylcholine (ACh) content during cultivation. The same treatment induced an early transient increase of the number of muscarinic cholinergic receptors (mAChR), as measured by [3H]quinuclidinyl benzilate binding to cell homogenate, that was followed by a dramatic decrease of the receptor density from the 9th day of culture. Atropine completely prevented the decrease of the maximal number of muscarinic recognition sites induced by NGF. Prolonged exposure of telencephalic neurons to NGF also induced a significant reduction of the relative content of the messenger RNA (mRNA) encoding m1 and m3 receptors, while the m4 transcript was increased by the treatment. We suggest that the prolonged stimulation of cholinergic neurons by NGF induces a downregulation of m1 and m3 mAChR and their mRNAs on the postsynaptic site, while it increases the synthesis of the functionally distinct m4 receptor subtype, which might be presynaptically localized on cholinergic neurons. The transient increase of the receptor number that occurs at the first days of culture was not paralleled by changes in the relative content of mAChR mRNAs and might be associated with the trophic activity of NGF on cholinergic synapses during early development.

Effects of estradiol on the ontogenesis of striatal dopamine D1 and D2 receptor sites in male and female rats

Since estradiol (E2) either increases or reduces the number of dopamine receptors in the corpus striatum of adult rats, depending on the dose and length of administration, the sensitivity of the two receptor subpopulations (D1 and D2) to E2 during ontogenesis was investigated. Rats of both sexes received either 10 micrograms/kg E2 for 3 days or 50 micrograms/kg for 6 days, and were sacrificed at the age of 15, 21, 40 and 120 days. D1 receptors (identified by [3H]SCH 23390 binding) displayed no changes in density and affinity in function of age, sex or E2 dose, whereas the D2 receptors (identified by [3H]spiperone binding) fell after the lower dose in all groups, and the higher dose resulted in supersensitivity in males of all ages, but only in the 15-day-old females. These findings show that the effect of E2 is bivalent on D2 density only. The effect of its brief administration at a low dose is not sex-dependent, whereas at higher doses administered for longer periods it appears to involve mechanisms linked to sexual differentiation after birth.

An analysis of lymphocyte 3H-N-methyl-scopolamine binding in neurological patients. Evidence of altered binding in Alzheimer's disease

Muscarinic cholinergic receptors were analysed in lymphocyte membranes from 35 patients with early (n = 20) and late onset (n = 15) Alzheimer's disease (AD), 86 patients with other neurological disorders and 60 normal controls by the specific binding of 3H-N-methyl-scopolamine (3H-NMS). The number of binding sites of 3H-NMS (Bmax) was significantly decreased both in early and late onset AD groups as compared with age-matched controls, by 54% and 40%, respectively, whereas the apparent binding affinity (Kd) was the same in all disease and control groups. In addition, the average Bmax in early AD was significantly lower than in late AD. The density of the binding of 3H-NMS was also significantly lower in a subgroup of old subjects with Down's syndrome (DS), whereas no changes were found in younger individuals with DS or in patients with Parkinson's disease, whether they were demented or not, multi-infarct dementia, myasthenia gravis or epilepsy. In the AD group, the difference in binding sites was unrelated either to the severity of dementia or disease duration. Treatment of the patients with cholinergic agents did not alter the binding values in any of the examined group. We conclude that the alteration of lymphocyte muscarinic receptors is highly associated with AD, but whether this reflects the central cholinergic deficit in these patients is uncertain.

Differential effects of indolepyruvic acid and 5-hydroxytryptophan on indole metabolism in the pineal gland of the rat during the light-dark cycle

The effect of two serotonin precursors, 5-hydroxytryptophan (5-OH-TRP) and indolepyruvic acid (IPA), a tryptophan ketoanalogue, on rat pineal indole metabolism during the light-dark cycle was investigated. 5-OH-TRP drastically increased the production of 5-hydroxyindoleacetic acid at a dose of only 10 mg/kg, whereas 50-100 mg/kg was needed to reach higher serotonin levels. It had no effect on the pathway leading to the production of N-acetylserotonin and melatonin. IPA, on the other hand, led to a marked dose-related increase in tryptophan, 5-OH-TRP, serotonin and 5-OH-indoleacetic acid, and was also active on N-acetylserotonin and melatonin synthesis in both phases. The different behaviour of these two substances with regard to melatonin synthesis was also confirmed by their effects on N-acetyltransferase, since IPA increased, whereas 5-OH-TRP decreased its activity. These data suggest that an increase in serotonin does not necessarily lead to an increase in melatonin, and that IPA may in fact induce this effect by altering the activity on N-acetyltransferase, which is regarded as a key enzyme in pineal hormone synthesis.

[Evaluation of the efficacy and tolerability of protirelin. Results of a multicenter study in Italy]

Controlled clinical trials demonstrated protireline tartrate (TRH-T) efficacy, with its analeptic, analgesic and arousing effects, in the treatment of neurological and functional impairment due to cerebrovascular accidents and head injuries. While the efficacy profile has been extensively studied, there isn't yet a completely satisfactory evaluation on TRH-T tolerability profile. We decided to perform, in Italy, a phase IV clinical trial on the efficacy-safety ratio of TRH-T, involving more than 170 centers spread in the whole country. The trial was an open study, with no control group, enrolling 2359 patients (M = 1405; F = 930; n.d. = 24), most aged between 50 and 80 years. About 52% of them had stroke sequelae, about 15% head injury, 11% a TIA and another 11% cerebral hemorrhage. The patients received TRH-T (4 mg/die) for a cycle of 14 days, by either intramuscular or intravenous routes (slow infusion). Drug efficacy was declared good in about 45% and excellent in about 18% of the patients with stroke. Two hundred twenty eight adverse events were found in 153 patients (M = 92; F = 61), namely with an incidence of 6.49%; they were more frequently detected in elderly patients and in those affected by cerebral hemorrhage or TIA. The most frequent adverse events concerned mucocutaneous, gastrointestinal, cardiovascular and central nervous systems; they were mostly considered light or moderate, and only one third of them required suspension of treatment. Drug-event causal relationship was judged, referring to the "Lasagna algorithm", as definite in 23.7% of the adverse events.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular mechanisms of homologous desensitization and internalization of muscarinic receptors in primary cultures of neonatal corticostriatal neurons

Homologous desensitization of muscarinic acetylcholine receptors (mAChR) was studied using primary cultures of corticostriatal neurons from neonatal rats. Prolonged incubation with carbachol attenuated phospholipase C responsiveness to muscarinic agonists and decreased the number of cell surface mAChR, as measured by binding of N-[3H] methylscopolamine to neuronal monolayers. When neurons were exposed to carbachol for 15 min, 40% of the mAChR lost from the membrane domain was recovered in the cytosol; a decrease of the total neuronal receptors was detected following an incubation with the agonist lasting longer than 15 min. Both 8-Br-cyclic AMP and forskolin neither affected N-[3H]methylscopolamine binding to cell monolayers or did they prevent the agonist-mediated mAChR desensitization. 8-Br-cyclic GMP also failed to decrease mAChR number. Pertussis toxin failed to prevent the homologous desensitization of mAChR under conditions that blocked the agonist-mediated inhibition of forskolin-stimulated cyclic AMP formation. The phorbol ester 12-O-tetradecanoyl-phorbol-12, 13-acetate induced a concentration-dependent decrease of N-[3H]methylscopolamine binding to neuronal monolayers. However, the protein kinase C inhibitors sphingosine and the ganglioside monosialosyl-gangliotetraglicosylceramide inhibited the 12-O-tetradecanoyl-phorbol-12,13-acetate-induced but not the agonist-induced desensitization of mAChRs. Furthermore, incubation with muscarinic agonists failed to translocate protein kinase C from cytosol to plasma membranes, as measured by binding of the phorbol ester [3H]-4-beta-phorbol-12,13-dibutyrate to neuronal monolayers. In corticostriatal neurons the agonist-induced desensitization and internalization of mAChR involves neither protein kinase C and protein kinase A activation nor changes in cyclic GMP and cyclic AMP content.

Induction of 2'-5' oligoadenylate synthetase and activation of ribonuclease in tamoxifen treated human breast cancer cell lines

In the present study the intracellular activity of oligoadenylate synthetase and ribonuclease have been evaluated in two human breast cancer cell lines treated with tamoxifen, a well known antiestrogenic drug. Increased levels of oligoadenylate synthetase and enhanced ribonuclease activity have been found in the cultures of CG5 cell line treated with concentrations of tamoxifen inhibiting cell growth. In the experiments with the EVSA-T cell line we found neither an antiproliferative effect nor an increased oligoadenylate synthetase and ribonuclease activity. It is likely that these enzymes are involved in the mechanisms by which this drug acts as an antiproliferative agent.

Are the catecholestrogens involved in estrogen-induced striatal dopamine receptor supersensitivity?

The ability of tamoxifen, an antiestrogen agent, to antagonise the striatal dopamine receptor hyperactivity induced in rats by chronic treatment with 17 beta-estradiol and 2-hydroxyestradiol or with two receptor blockers (haloperidol and sulpiride) was compared. It was found that tamoxifen antagonised both the increase in [3H]spiperone binding sites and the stereotyped behaviour induced by apomorphine in animals treated with the two steroids but had no effect in animals receiving the two dopamine blockers. These results run counter to the view that introduction of a catechol group in a steroid molecule is of decisive importance in the induction of striatal dopamine receptor hypersensitivity.

[3H]N-methylscopolamine binding to muscarinic receptors in human peripheral blood lymphocytes: characterization, localization on T-lymphocyte subsets and age-dependent changes

The properties of the binding of the muscarinic receptor ligands, [3H]quinuclidinyl benzilate ([3H]QNB) and [3H]N-methylscopolamine ([3H]NMS) in human mononuclear cells were compared. The binding of [3H]QNB showed a high, non-specific component and lack of saturability in both intact mononuclear cells and preparations of lysed mononuclear cell membranes. Conversely the specific binding of [3H]NMS had a high affinity and was saturable at concentrations greater than 30 nM in both intact and broken cells. Classical muscarinic receptor antagonists displaced specific binding of [3H]NMS binding according to the law of mass action, while displacement curves for pirenzepine and muscarinic agonists were very shallow (nH less than 1), suggesting the presence of more than one subtype of muscarinic receptor on mononuclear cell membranes. Binding studies with [3H]NMS to purified mononuclear cell subpopulations demonstrated that muscarinic binding sites were mainly localized on thymus-derived (T) lymphocytes and large granule lymphocytes. Moreover evidence is presented of an age-dependent increase of the density of muscarinic binding sites on T-lymphocytes. The results are discussed in terms of the usefulness of the binding of [3H]NMS in studying the physiological function of muscarinic receptors on human T-lymphocytes and their possible changes in patients with neurological diseases.

Further study on the changes in the concentration of prolactin-binding sites in different organs of Xenopus laevis male and female, kept under dry conditions and then returned to water (their natural habitat)

The binding of 125I-labeled ovine prolactin (125I-oPRL) to membranes from the kidney and liver of Xenopus laevis male and female specimens (Experiment I) and from the kidney, epidermis, and liver of female specimens (Experiment II) (1) kept in an aquatic environment, (2) exposed for 2 weeks to dehydrating conditions, and (3) then placed back into their aquaria after exposure to dehydrating conditions (Experiment II) was studied. No significant sex differences in PRL binding to kidney, epidermis, and liver were found. A highly significant drop in PRL specific binding to the membranes from the kidney and epidermis is brought about in the specimens from both sexes exposed to dehydrating conditions. The results obtained by MgCl2 treatment in vitro of the membranes under study for an estimation of total PRL receptor concentrations seem to point to an actual decrease in PRL specific binding sites. The values of PRL specific binding to the membranes from the liver are not affected by dehydration of the animals (Experiment I and II) or their subsequent rehydration (Experiment II). In rehydrated females (Experiment II), PRL binding values were closely related to those recorded in females permanently maintained in water (controls).

Positive interaction between interferon and bleomycin in vitro and in animal experimental models

Effect of combined bleomycin and interferon on cell growth was evaluated in vitro, on 2 leukemia cell lines, and on mice bearing a murine leukemia. Human alpha-A interferon or murine alpha-beta interferon were used. Synergism was observed in both models and the sequence of administration was decisive in this respect. The in vivo results were not completely comparable with those observed in vitro. This finding suggests that the in vitro results reflect the direct effects of the drugs on tumor cells, meanwhile the interaction between drugs in vivo are affected by pharmacokinetic characteristics and by host defense systems.

Phase II study of alpha-interferon plus bleomycin in advanced non-small cell lung cancer

A synergistic effect between alpha-Interferon and Bleomycin has been recently shown in in vitro and in vivo experimental systems. Although active, Bleomycin and other antineoplastic drugs give low response rates in non-small cell lung cancer, but, like the other antineoplastic agents, responses are short-lived. We treated 13 patients with advanced non-small cell lung cancer with the combination Bleomycin 15 mg/m2 i.v. at hour 0 and alpha-Interferon 9 X 10(6) U i.m. given at hours 6, 30 and 54. Major side effects were pyrexia, astenia and anorexia; only one case of moderate leukopenia was observed. No major responses were obtained and stable disease lasted a median of 5 months. Further study of this combination is not warranted in patients with pretreated non-small cell lung cancer.

Prolactin receptors on large granular lymphocytes: dual regulation by cyclosporin A

Although evidence has been provided for a modulatory role of prolactin (PRL) on humoral and cell-mediated immune responses and PRL receptors have been found on T and B lymphocytes, no indications exist concerning the influence of PRL on natural killer (NK) activity nor has a structural basis for interaction been found on the NK effector cells (large granular lymphocytes, LGL). We show here that highly purified LGL express binding sites for PRL. The calculated receptor number was 660 per cell and the dissociation constant (Kd) was 3.0 X 10(-10) M. Since previous studies have reported that cyclosporin (CsA), an immunosuppressive agent used in organ transplant patients, affects the binding of PRL to T and B lymphocytes, but not to rabbit mammary gland cells, we investigated whether this compound could alter the binding of the hormone to LGL. At concentrations from 10(-7) to 10(-6), corresponding to the therapeutical range, CsA induced a complete inhibition of the PRL binding. By contrast, concentrations of CsA ranging from 10(-11) to 10(-9) increased the PRL binding to more than 100% of control levels. In addition to their antitumor role, LGL have been proposed to participate in graft versus host disease and in transplant rejection. The finding that CsA can differently affect PRL-receptor expression on LGL points to an involvement of CsA--PRL interactions in determining the output of these immune responses. In addition, these data strongly support the idea of a close relationship between the neuroendocrine and immune systems.

Tamoxifen counteracts estradiol induced effects on striatal and hypophyseal dopamine receptors

We investigated the ability of Tamoxifen (TAM), an antiestrogen drug, to counteract the modifications induced by estrogens on dopamine (DA) receptors on striatum and on adenohypophysis of ovex female rats. Subacute treatment with 17 beta-estradiol (E2) at both low (0.1 micrograms/kg) and high (20 micrograms/kg) doses confirmed its ability to increase the number of striatal 3H-Spiperone (3H-SPI) binding sites in a dose dependent manner. By contrast in the pituitary, only high doses of estrogen were effective in reducing the number of DA receptors. We treated ovex female rats for 15 days with TAM alone or associated with E2, to see if these estrogenic effects could be suppressed by an antiestrogenic drug. TAM did not affect the number of striatal DA receptors, but significantly increased the adenohypophyseal DA binding sites, without varying their affinity. No changes were observed in pituitary and striatal DA receptor density, even when TAM was injected in association with estradiol.

IN CONCLUSION

TAM is able to counteract the effects estrogens have on DA receptors. However there is some evidence that it could influence the pituitary DA systems independently of its antiestrogenic activity.

Phosphatidylserine activity on prolactin brain receptors of aged rabbits

1. PRL receptors in the hypothalamus and substantia nigra of aged rabbits (28-month-old) are significantly reduced in comparison with young rabbits (6-month-old). 2. Repeated treatments with BC-PS are able to gradually increase the PRL receptor number both in hypothalamus and nigra. However only after 30 days of treatment the binding reaches the mean values observed in young rabbits. 3. Aged rabbits showed an evident increase in PRL plasma levels in comparison with young animals. In BC-PS treated animals this increase was not more apparent. Moreover in young rabbits treated with BC-PS an evident decrease in basal PRL plasma levels was observed.

Drug sensitivity tests after cell separation on density gradients

Cells from two leukaemic cell lines (K562 and L1210) were separated on a discontinuous Percoll gradient with densities from 1040 to 1090 by centrifugation. The cells recovered from gradient interfaces were checked for their DNA content and subjected to two different drug sensitivity tests using three cytostatic drugs. The purpose of the study was to compare the sensitivity of a sample of the whole population with that of the fractions thus obtained. Depending on the test used and the line tested, there was a 5.5 to 55.5% discordance between the results for the fractions and the non-separated cells.

In vitro evaluation of myelotoxicity induced by antineoplastic drugs

Myelotoxicity is one of the most important side effects of antineoplastic drugs. Even in using the same dosages, the gravity of this toxicity varies greatly among different patients. With the aim of evaluating if an in vitro test may predict such an effect we have measured in bone marrow samples taken from 15 patients undergoing chemotherapy for small-cell lung cancer the in vitro uptake of 3H-thymidine in the presence or absence of the cytostatic drugs used for the clinical treatment of these patients. We did not find a clear correlation between the in vitro results and the myelotoxicity observed during the clinical course.

Pharmacokinetics of norfloxacin in healthy volunteers and patients with renal and hepatic damage

The pharmacokinetics of norfloxacin were studied in six healthy volunteers, and three patients each with moderate renal and hepatic damage. A new specific and sensitive high performance liquid chromatography method was set up to measure plasma and urine concentrations of norfloxacin. The mean urinary concentrations after a single oral dose of 400 mg norfloxacin exceeded many times the MIC and MBC values of most of the bacterial strains responsible for urinary tract infections. Results in the patients with hepatic and renal damage indicated slight and not statistically significant differences in comparison with healthy volunteers.

Changes in the concentration of uterine cytoplasmic oestrogen receptors induced by doxorubicin and methotrexate

The effects of doxorubicin and methotrexate on the oestradiol-induced depletion, replenishment and subsequent increase beyond the normal value (overshoot) in the number of uterine cytoplasmic oestrogen receptors were investigated in intact rats. Injection of doxorubicin (0.5 mg/kg, i.v.) or methotrexate (1mg/kg, i.m.) 5 min after a single i.p. injection of 10 ng oestradiol-17beta (which is able to induce a 50% depletion in the number of oestrogen receptors) caused a significant increase in the oestradiol-induced depletion. Both drugs inhibited the replenishment and the overshoot phases until 48 h after treatment, although the effect was more marked with doxorubicin. Experiments in vitro showed that both methotrexate and doxorubicin affected the capacity of oestradiol-17beta to bind to specific cytoplasmic receptors, inducing an increase in binding when used at low concentrations and a decrease at higher concentrations. The effects of doxorubicin and methotrexate on the depletion, replenishment and overshoot of oestrogen receptors seemed to be partly dependent on the inhibition of protein synthesis and partly due to direct action on the binding of oestradiol-17beta to its receptors.