[Laparoscopic treatment of neoplasms of the body end tail of the pancreas: technical notes]

The authors report a new approach to pancreatic laparoscopic body end tail that allows resection for neoplastic disease. This procedure permits en bloc resection using endogia 45 without preventive dissection of splenic vessels.

Design and monitoring of photostability systems for amlodipine dosage forms

Photostability of amlodipine (AML) has been monitored in several pharmaceutical inclusion systems characterized by plurimolecular aggregation of the drug and excipients with high molecular weight. Several formulations including cyclodextrins, liposomes and microspheres have been prepared and characterized. The photodegradation process has been monitored according to the conditions suggested by the ICH Guideline for photostability testing, by using a light cabinet equipped with a Xenon lamp and monitored by spectrophotometry. The formulations herein tested have been found to be able to considerably increase drug stability, when compared with usual pharmaceutical forms. The residual concentration detected in the inclusion complexes with cyclodextrins and liposomes was 90 and 77%, respectively, while a very good value of 97% was found for microspheres, after a radiant exposure of 11,340 kJm(-2).

[A rare case of nerve-sheath sarcoma with rhabdomyoblastic differentiation (malignant triton tumor)]

Malignant peripheral nerve sheath tumors (MPNST) are spindle-cell sarcomas that appear in a setting of neurofibroma or schwannoma or are associated with peripheral nerves or demonstrate nerve sheath differentiation. Malignant triton tumor (MTT) is a subtype of MPNST that also contain tissue with skeletal muscle differentiation (embryonal, plemorphic and botryoid rhabdomyosarcoma). The estimated incidence of MPNSTs in patients with NF1 is 2-5% compared with 0.0001% in the general population and approximately 69% of the reported cases of MTT are associated with von Recklinghausen disease. In July 2002 a 37-year old man was readmitted to the Department of Oncologic Surgery of the S. Camillo-Forlanini Hospital in Rome for both a right-sided retroperitoneal paravertebral not palpable mass, incidentally detected at a follow-up MRI, and a left-sided popliteal mass, discovered at clinical evaluation. Seventeen months before, when the patient underwent surgery at the same Department for both a left-sided paravertebral inferior mediastinal neurofibroma and a right-sided axillary neurofibroma, diagnosis of von Recklinghausen disease (NF1) was made, according to the criteria established by the NIH Consensus Development. Conference on Neurofibromatosis of 1987. A xifopubic laparotomy was performed: the tumor appeared to be localized, well-capsulated and strictly associated to the lumbar and sacral nervous radicles (L4, L5, S1) without evidence of invasion. The tumor was completely resected with sparing of the psoas muscle and the lumbar plexus through a subperineural dissection technique. No intra-operative pathologic examination was performed. Postoperative pathologic findings showed evidence for a trition tumor. The popliteal mass was resected too and resulted to be a neurofibroma just like the tumors resected 17 months before when diagnosis of von Recklinghausen disease was made. The patient was disease free 6 months after initial surgery. Sarcoma arising in anatomic site other than extremity and superficial trunk are often more difficult to control because of anatomic constraints, delayed disease presentation, proximity to neurovascular and osseous structures and toxicity for normal adjacent tissues that limits the use of adequate radiation doses. Indeed, the anatomic site is an important prognostic factor in STS and the prognosis for retroperitoneal tumors is considerably worse than for extremity tumors. Reported local recurrence rates for retroperitoneal sarcomas range from 40% to 80% and, in marked contrast to extremity STS, most of patients can and do die from local recurrence in the absence of metastasis. In contrast to the benefit most patients with high grade soft tissue sarcomas of the extremities receive from adjuvant radiation and chemotherapy, these modalities have been of little value for retroperitoneal tumors. To overcome the problem of dose limitation, intraoperative electron beam radiotherapy (IORT) in combination with ERBT has been proposed. IORT plus ERBT was found to improve local control of disease in recent clinical trials. Current chemotherapy for retroperitoneal sarcomas is ineffective. Local adjuvant therapy such as intraperitoneal chemotherapy or experimental immunotherapy seems to be attractive in theory, but needs further investigations through prospective randomized multicentric trials. In conclusion, to date aggressive surgical management remains the most effective modality for selected primary and recurrent retroperitoneal soft tissue sarcomas including MPNSTs and the subtype MTT. Patients with incomplete resection and other risk factors such as younger age and high grade tumors may be suitable candidates for investigational adjuvant therapy.

[Staging videolaparoscopy of peritoneal carcinomatosis]

The peritoneal surface malignancy is an high risk condition which implies high postoperative mortality also for simple explorative laparotomy. A technique of staging laparoscopy was assessed and is here described: the technique reveals to be safe, feasible and reliable. The accuracy of the procedure depends our the surgeons experience and familiarity with the concepts of PCI and cytoreduction.

Quinoxalinylethylpyridylthioureas (QXPTs) as potent non-nucleoside HIV-1 reverse transcriptase (RT) inhibitors. Further SAR studies and identification of a novel orally bioavailable hydrazine-based antiviral agent

Quinoxalinylethylpyridylthioureas (QXPTs) represent a new class of human immunodeficiency virus type 1 (HIV-1) non-nucleoside reverse transcriptase (RT) inhibitors (NNRTIs) whose prototype is 6-FQXPT (6). Docking studies based on the three-dimensional structure of RT prompted the synthesis of novel heteroarylethylpyridylthioureas which were tested as anti-HIV agents. Several compounds proved to be potent broad-spectrum enzyme inhibitors and significantly inhibited HIV-1 replication in vitro. Their potency depends on the substituents and the nature of the heterocyclic skeleton linked to the ethyl spacer, and structure-activity relationships are discussed in terms of the possible interaction with the RT binding site. Although the new QXPTs analogues show potent antiviral activity, none of the compounds tested overcome the pharmacokinetic disadvantages inherent to ethylpyridylthioureidic antiviral agents, which in general have very low oral bioavailability. Through an integrated effort involving synthesis, docking studies, and biological and pharmacokinetic evaluation, we investigated the structural dependence of the poor bioavailability and rapid clearance within the thioureidic series of antivirals. Replacing the ethylthioureidic moiety with a hydrazine linker led to a new antiviral lead, offering promising pharmacological and pharmacokinetic properties in terms of antiviral activity and oral bioavailability.

Inhibition of matrix metalloproteinases by over-expression of tissue inhibitor of metalloproteinase-2 inhibits the growth of experimental hemangiomas

Inhibitors of proteases prevent tumor-associated matrix degradation, affecting tumor growth, angiogenesis and metastasis. Our study was designed to investigate the effect of inhibition of matrix metalloproteinases (MMPs) on the growth of experimental hemangiomas, using the model of murine endothelioma eEnd.1 cells. In nude mice, these cells generate hemangiomas, consisting mostly of host-recruited endothelial cells, whose growth requires the activity of MMPs. In vitro, eEnd.1 cells produce factors that recruit endothelial cells and stimulate them to release MMPs. Over-expression of TIMP-2, following retrovirus-mediated gene transfer, decreased tumor growth in vivo. The infected clone CR1, which produces high levels of TIMP-2 (as assessed by Northern blot, ELISA and reverse zymography), formed slow-growing tumors that did not grow beyond 0.4 g, while clone 1H, which produces little TIMP-2, grew not dissimilarly to mock-infected cells and parental e.End.1 cells. Histologically, control tumors presented the features of cavernous hemangiomas, while CR1 tumors had a more solid pattern, showing foci of apoptotic cells. In vitro, TIMP-2 over-expression had no autocrine anti-proliferative effect on endothelioma cells but reduced their ability to recruit endothelial cells. CR1 cells lacked the capacity of mock-infected or parental eEnd.1 cells to stimulate endothelial cell motility and invasiveness. Antibodies against TIMP-2 restored the ability of CR1 to induce endothelial cell invasion. We conclude that, in this model, genetic increase of TIMP-2 inhibits tumor growth, apparently by affecting the recruitment and organization of host endothelial cells by the transformed cells.

Isolation and characterization of an acute promyelocytic leukemia cell line selectively resistant to the novel antileukemic and apoptogenic retinoid 6-[3-adamantyl-4-hydroxyphenyl]-2-naphthalene carboxylic acid

6-[3-adamantyl-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437) is a novel compound that represents the prototype of a new class of synthetic retinoids with apoptogenic properties in acute promyelocytic leukemia (APL) and other types of leukemia. In this article, using SCID mice xenografted with APL-derived NB4 cells, we demonstrate that CD437 has significant antileukemic activity in vivo. In addition, we report on the isolation and characterization of an APL cell line (NB4.437r) resistant to CD437. The cell line retains expression of PML-RARalpha and is approximately 33-fold more resistant than the parental counterpart to the apoptogenic effects of the retinoid. Resistance is relatively specific to CD437 and structural congeners because the NB4.437r cell line is still sensitive to various types of apoptogenic compounds. The CD437-resistant cell line maintains sensitivity to the antiproliferative and apoptotic action of all-trans-retinoic acid, AM580, and fenretinide, though it shows partial resistance to the cytodifferentiating effects of the first 2 compounds. Resistance to CD437 lays upstream of the CD437-induced release of cytochrome c from the mitochondria and the activation of caspase-3, -7, -8, and -9. Furthermore, NB4.437r cells are deficient in the CD437-dependent activation of nuclear NFkb and AP1-binding activities and in the phosphorylation of the protein kinase Akt. In the case of AP1, deficient assembly of the complex is not caused by the lack of activation of the Jun N-terminal kinase (JNK) family of kinases. The novel cell line will be useful in the elucidation of the molecular mechanisms underlying the apoptogenic action of CD437 and structurally related retinoids. (Blood. 2000;95:2672-2682)

Thiazolothiazepine inhibitors of HIV-1 integrase

A series of thiazolothiazepines were prepared and tested against purified human immunodeficiency virus type-1 integrase (HIV-1 IN) and viral replication. Structure-activity studies reveal that the compounds possessing the pentatomic moiety SC(O)CNC(O) with two carbonyl groups are in general more potent against purified IN than those containing only one carbonyl group. Substitution with electron-donating or -withdrawing groups did not enhance nor abolish potency against purified IN. By contrast, compounds with a naphthalene ring system showed enhanced potency, suggesting that a hydrophobic pocket in the IN active site might accommodate an aromatic system rather than a halogen. The position of sulfur in the thiazole ring appears important for potency against IN, as its replacement with an oxygen or carbon abolished activity. Further extension of the thiazole ring diminished potency. Compounds 1, 19, and 20 showed antiviral activity and inhibited IN within similar concentrations. These compounds inhibited IN when Mn(2+) or Mg(2+) was used as cofactor. None of these compounds showed detectable activities against HIV-1 reverse transcriptase, protease, virus attachment, or nucleocapsid protein zinc fingers. Therefore, thiazolothiazepines are potentially important lead compounds for development as inhibitors of IN and HIV replication.

Diagnostic and prognostic value of peritoneal immunocytology in gastric cancer

PURPOSE

Among the clinical factors with a pivotal role in the prediction of outcome for patients with gastric cancer, intraperitoneal (i.p.) microscopic dissemination may represent an important cause of recurrences, even in the early stages of the disease. In this context, the cytologic examination of intraoperative peritoneal washings may be essential to identify metastatic free cells, although a number of false-negative cases may be encountered.

PATIENTS AND METHODS

To determine whether immunocytochemical (ICC) methods that used a panel of three monoclonal antibodies (MoAbs), B72.3, AR3, and BD5, directed to gastric cancer-associated antigens can improve peritoneal cytology by providing more accurate prognostic indications, we immunocytochemically and morphologically evaluated 144 peritoneal washings sampled from patients surgically treated for gastric cancer.

RESULTS

The ICC analysis allowed the identification of metastatic free peritoneal cells in 35% of the patients, with a 14% improvement over routine cytopathology (P < .0001). Furthermore, a 54-month survival analysis by Kaplan-Meier curves showed a statistically significant decrease in overall survival (OS) in patients with stages I through III disease with peritoneal microscopic disease detected morphologically and/or by ICC at the time of the primary surgery.

CONCLUSION

Our data indicate that the use of a combination of selected MoAbs may allow the identification of cytologically false-negative cases that provide valuable prognostic information. This may be useful to stratify patients on more adequate therapeutic trials.

New antipsychotic agents with serotonin and dopamine antagonist properties based on a pyrrolo[2,1-b][1,3]benzothiazepine structure

The development of a synthetic approach to the novel pyrrolo[2, 1-b][1,3]benzothiazepine and its derivatives and their biological evaluation as potential antipsychotic drugs are described. In binding studies these compounds proved to be potent 5-HT2, D2, and D3 receptor ligands. The more potent benzothiazepine (+/-)-3b was resolved into its enantiomers by using HPLC techniques. In vitro testing confirmed that (-)-3b is a more potent D2 receptor ligand, maintaining high affinity for 5-HT2 receptors. In contrast, the (+)-3b enantiomer presents a 35 times higher affinity for 5-HT2 than for dopamine D2 receptors with a similar dopamine D1 receptor affinity to that of (-)-3b. Overall, (+)-3b shows an "atypical" neuroleptic binding profile, while (-)-3b has a more "classical" profile. Furthermore pharmacological and biochemical testing displayed that the novel benzothiazepine (+/-)-3b is able to increase the extracellular levels of dopamine in the rat striatum and causes a dose-related suppression of apomorphine-induced locomotor activity. At low doses (+/-)-3b does not induce catalepsy, showing atypical antipsychotic properties similar to those of olanzapine. These heterocyclic compouds represent new leads for the development of novel antipsychotic drugs with atypical properties.

Gastric cancer. Clinico-biological updating and analysis of 400 operated cases

Gastric cancer is a rather common disease worldwide. In Italy it still accounts for 15,000 deaths annually. A sharp drop in the incidence rate of Lauren's intestinal histotype has been reported, whereas the frequency of the diffuse histotype is relatively steady. If the histogenesis of the latter is still somewhat obscure, the intestinal type confirms the sequence: atrophic gastritis--intestinal metaplasia--dysplasia--neoplasia. These different stages of development can nowadays be singled out through a series of indicators, the most reliable of which are the pepsinogen I/pepsinogen II ratio, the presence of sulphomucins and Lewis antigens in the gastric juices and NOR (Nucleolar Organizer Regions), cell ploidy and oncogenes determination. The genes involved in the neoplastic transformation are mostly oncosuppressors, the most frequent alterations being those relative to the APC gene, p53 and c-myc. In addition to the by now indispensable pathological staging of the disease, the modern prognostic factors are arising great interest: the most significant are the immunohistochemical examination of the peritoneal washing, and cell ploidy. Surgery is still the only potentially curative treatment: the earlier surgery is performed in the course of disease, the greatest the curative potential. The Authors' experience, which includes 400 operated cases with complete follow-up records, is here reported. The resectability rate turned out to be 84%, overall operative mortality was 6.5% with that due to surgical causes along being 3.7%. Overall survival at 5 years was 36%, while that of the curative operations 47%. Good results were obtained with the association surgery + intraoperative radiotherapy which resulted in a significant decrease in local recurrences of the disease.

Batimastat, a synthetic inhibitor of matrix metalloproteinases, potentiates the antitumor activity of cisplatin in ovarian carcinoma xenografts

Batimastat (also known as BB-94) is a synthetic matrix metalloproteinase inhibitor that has shown antineoplastic and antiangiogenic activity in various tumor models. In this study, two human ovarian carcinoma (HOC) xenografts (HOC22 and HOC8) were used to investigate the effect of batimastat on the antineoplastic activity of cisplatin. Both xenografts produced ascites and solid lesions in the peritoneal cavity of nude mice. HOC cells were inoculated i.p. in nude mice, and treatment was started at different stages of the disease. Batimastat was administered alone or concurrently with or subsequent to cisplatin therapy. In all of the protocols, the response of HOC xenografts was confirmed by cytological analysis of ascites and histological examination of the organs in the peritoneal cavity. Treatment of nude mice bearing early-stage (3 days after tumor implantation) HOC22 or HOC8 with cisplatin or batimastat alone delayed tumor growth and increased the survival time of the mice, although all animals eventually died. In contrast, treatment with batimastat (60 mg/kg i.p. every other day, for a total of eight injections) concomitantly with cisplatin (4 mg/kg i.v., every 7 days for a total of three injections) completely prevented growth and spread of both xenografts, and all animals were alive and healthy on day 200. The potentiation of cisplatin's activity by batimastat was dose dependent and was observed in the treatment of both advanced (7 days after tumor inoculation) and late-stage (20 days after inoculation) tumor. The administration of batimastat following cisplatin therapy also led to significant improvement in the survival of mice compared to treatment with cisplatin alone. These results suggest a potentiation of the antineoplastic activity of cisplatin by batimastat and support the use of the two agents in combination in the treatment of ovarian cancer patients.

Antiproliferative action of pyrrolobenzoxazepine derivatives in cultured cells: absence of correlation with binding to the peripheral-type benzodiazepine binding site

Three novel peripheral-type benzodiazepine binding site (PBBS) ligands, NF 182, 213 and 262, along with the classically used PBBS ligands, PK 11195 and Ro5-4864, were found to inhibit, at micromolar concentrations and in dose-dependent manner, the proliferation of rat C6 glioma and human 1321N1 astrocytoma, without being cytotoxic. This antiproliferative effect is mediated by arrest in the G1 phase of the cell cycle and does not appear to be mediated by a specific interaction of these ligands with the peripheral-type benzodiazepine binding site.

A human acute lymphoblastic leukemia line with the T(4;11) translocation as a model of minimal residual disease in SCID mice

This study describes a new human acute lymphoblastic leukemia (ALL) cell line (ALL-PO) with the t(4;11) translocation established in SCID mice. The ALL-PO line can be maintained by serial transplant in SCID mice with stable immunophenotypic, molecular and karyotypic features. After intravenous (i.v.) injection ALL-PO spread systemically involving the hematopoietic organs and the central nervous system (CNS) of all mice. The homing and the progression of the disease are evaluated by histological analysis and reverse-transcriptase polymerase chain reaction (RT-PCR) amplification of the t(4;11) translocation in the bone marrow, spleen and CNS of SCID mice at different times after engraftment. Occult leukemia was detectable by PCR in the bone marrow of SCID mice as early as three days after the i.v. injection of leukemic cells whereas the first signs of involvement of the spleen and CNS appeared after 14 days; after 24 days all the mice were euthanized because they were moribund and the bone marrow, spleen and CNS showed ample infiltration by leukemic cells. The sensitivity to conventional chemotherapy was tested in this model. ALL-PO in SCID mice did not respond to treatment with vincristine or idarubicin but cyclophosphamide (150 mg kg(-1) i.v., single injection) significantly increased the survival of the mice. The efficacy of such a treatment was more evident when cyclophosphamide was given in the early stages of the disease (detectable only by molecular analysis) but much less effective when the drug was administered when the disease could be detected by conventional histological analysis. The biological behavior and molecular characteristics of ALL-PO make it a good model for studying novel therapeutic strategies for a better control of minimal residual disease.

DNA ploidy, proliferative index and EGF-R status in 130 cases of resected gastric cancer--a multivariate analysis

BACKGROUND/AIMS

The purpose of this study was to define the prognostic role of DNA ploidy, proliferative index and EGF-R status in resected gastric cancer.

MATERIALS AND METHODS

Ten clinico-pathological parameters and three biological factors obtained from flow cytometry and immunohisto-chemistry were evaluated in a series of 130 gastric cancer patients who received surgical treatment, including 28 stage IV cases (21.6%), using paraffin-embedded and fresh specimens in 77.7% and 22.3% of the cases, respectively. These variables were first analyzed and tested for correlation within the whole series and then weighted against survival in 117 applicable cases through univariate and multivariate analyses.

RESULTS

Aneuploidy was significantly related to higher proliferative activity, EGF-R expression and deeper stomach wall infiltration. Higher proliferative activity was significantly related to deeper stomach wall infiltration and larger tumor diameter. The latter showed a significant relationship to EGF-R expression. Univariate analysis showed the significant variables for survival to be DNA ploidy, pT, pN, M, stage, histological type according to Lauren and tumor diameter. Multivariate analysis calculated on these significant variables using the Cox multiple stepwise regression model detected three factors which independently influence survival: pathological stage (p < 0.00001), histological type according to Lauren (p < 0.002) and DNA ploidy (p < 0.03).

CONCLUSIONS

DNA ploidy was shown to be a significant prognostic parameter in resected gastric cancer after pathological stage and histological type according to Lauren. The prognostic roles of proliferative activity and EGF-R status require further investigation.

Increase in beta-galactosidase activity in a non-isothermal bioreactor utilizing immobilized cells of Kluyveromyces fragilis: fundamentals and applications

The beta-galactosidase activity of Kluyveromyces fragilis cells immobilized in a kappa carrageenan gel was studied in a bioreactor functioning under isothermal and non-isothermal conditions. We observed an increase in enzyme activity which was found to be proportional to the intensity of the temperature gradient applied across the biocatalytic membrane, as well as to the average temperature of the bioreactor. The efficiency of such a non-isothermal bioreactor was calculated with respect to the yield of a bioreactor working under comparable isothermal conditions and was evaluated in terms of reduction of processing times in industrial applications. The possibility that enzyme activity in living cells is affected by non-isothermal conditions naturally existing owing to metabolic heat production is also discussed.

IL-1alpha gene-transfected human melanoma cells increase tumor-cell adhesion to endothelial cells and their retention in the lung of nude mice

The interleukin-1alpha(IL-1) gene was introduced by retroviral gene transfer into the A375P human melanoma cell line. Two hygromycin-resistant colonies, colony 3 and colony 6, which respectively do not and do express and release IL-1, were selected on the basis of Northern blot and ELISA. Both colonies adhered to resting human endothelial cells (EC) to the same extent. Pre-treatment of EC for 6 hr with conditioned medium (CM) from colony 6, but not from colony 3, increased the adhesion of A375P melanoma and HT-29 colon-carcinoma cells to EC. This increase was blocked by adding interleukin-l-receptor antagonist (IL-1ra) to the EC monolayer. Treatment of EC with colony-6-CM increased the expression of intercellular-adhesion molecule I (ICAM-1), vascular-cell-adhesion molecule I (VCAM-1) and E-selectin. Co-cultivation of colony-6 but not colony-3 melanoma cells with EC caused time-dependent increased expression of these adhesion proteins, reflecting their kinetics of expression on EC. Treating the EC with monoclonal antibodies to VCAM-1 and E-selectin abolished the colony-6-CM-induced increase in adhesion respectively to A375P melanoma and HT-29 colon-carcinoma cells. In vivo, i.v. injection of colony-6 cells in nude mice increased the expression of VCAM-1 on lung microvascular EC. The retention of radiolabeled A375P melanoma cells in the lung was increased in nude mice primed with colony-6 cells, but not with colony-3 cells, injected 6 hr earlier. These results demonstrate that IL-1 produced constitutively by transformed A375P melanoma cells is functionally active, inducing adhesion molecules on EC that enhance their adhesiveness for tumor cells and increase tumor-cell retention in the lung of nude mice.

Synthesis, biological activity, and SARs of pyrrolobenzoxazepine derivatives, a new class of specific "peripheral-type" benzodiazepine receptor ligands

The "peripheral-type" benzodiazepine receptor (PBR) has been reported to play a role in many biological processes. We have synthesized and tested a novel series of PBR ligands based on a pyrrolobenzoxazepine skeleton, in order to provide new receptor ligands. Several of these new compounds proved to be high affinity and selective ligands for PBR, and benzoxazepines 17f and 17j were found to be the most potent ligands for this receptor to have been identified to date. The SAR and the molecular modeling studies detailed herein delineated a number of structural features required for improving affinity. Some of the ligands were employed as "molecular yardsticks" to probe the spatial dimensions of the lipophilic pockets L1 and L3 in the PBR cleft and to determine the effect of occupation of L1 and L3 with respect to affinity, while other C-7 modified analogues provided information specifically on the hydrogen bonding with a putative receptor site H1. The new pyrrolobenzoxazepines were tested in rat cortex, a tissue expressing high density of mitochondrial PBR, and exhibited IC50 and Ki values in the low nanomolar or subnanomolar range, as measured by the displacement of [3H]PK 11195 binding. A subset of the highest affinity ligands was also found to have high affinities for [3H]PK 11195 and [3H]Ro 5-4864 binding in rat adrenal mitochondria. All the ligands in this subset are stimulators of steroidogenesis having similar potency and extent of stimulation as PK 11195 and Ro 5-4864 of steroidogenesis in the mouse Y-1 adrenocortical cell line.

Cardiovascular characterization of pyrrolo[2,1-d][1,5]benzothiazepine derivatives binding selectively to the peripheral-type benzodiazepine receptor (PBR): from dual PBR affinity and calcium antagonist activity to novel and selective calcium entry blockers

The synthesis and cardiovascular characterization of a series of novel pyrrolo[2,1-d][1,5]-benzothiazepine derivatives (54-68) are described. Selective peripheral-type benzodiazepine receptor (PBR) ligands, such as PK 11195 and Ro 5-4864, have recently been found to possess low but significant inhibitory activity of L-type calcium channels, and this property is implicated in the cardiovascular effects observed with these compounds. In functional studies both PK 11195 (1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxa mide) and Ro 5-4864 (4'-chlorodiazepam) did not display selectivity between cardiac and vascular tissue. Therefore, several 7-(acyloxy)-6-arylpyrrolo[2,1-d][1,5]benzothiazepines, potent and selective peripheral-type benzodiazepine receptor ligands recently developed by us (3, 7-20), were subjected to calcium channel receptor binding assay. Some of these compounds showed an unexpected potency in displacing the binding of [3H]nitrendipine from L-type calcium channels, much higher than that reported for PK 11195 and Ro 5-4864 and equal to or higher than that of reference calcium antagonists such as verapamil and (+)-cis-diltiazem. Specifically, in rat cortex homogenate, our prototypic PBR ligand 7-acetoxy-6-(p-methoxyphenyl)pyrrolo[2,1-d][1,5]benzothiazepine (3) showed an IC50 equal to 0.13 nM for inhibition of [3H]nitrendipine binding. Furthermore, in functional studies this compound displayed a clear-cut selectivity for cardiac over vascular tissue. Comparison of calcium antagonist activity on guinea pig aorta strips with the negative inotropic activity, determined by using isolated guinea pig left atria, revealed that 3 displayed higher selectivity than the reference (+)-cis-diltiazem. Thus, the pyrrolobenzothiazepine 3 might represent a new tool for characterizing the relationship between the PBR and cardiac function. Furthermore, we have also investigated the structural dependence of binding to PBR and L-type calcium channels, and this study allowed us to identify a new class of potent calcium channel blockers selective for cardiac over vascular tissue, with no affinity for PBR. A number of structure-activity relationship trends have been identified, and a possible explanation is advanced in order to account for the observed differences in selectivity. Three structural features, namely, (i) the saturation of the C(6)-C(7) double bond, with a consequent higher molecular flexibility, (ii) the presence of a substituent in the benzofused ring, and (iii) a basic side chain at C-10 of the pyrrolobenzothiazepine ring system, were found to be responsible for potent L-type calcium channel antagonism and clear-cut selectivity for cardiac over vascular tissue. Among the synthesized compounds the pyrrolobenzothiazepine 62 was found to be the most promising selective calcium channel blocker. Additionally, the molecular structure determination of the key intermediate 48 by X-ray diffraction, molecular modeling, and NMR analysis is reported.

Pyrrolobenzothiazepinones and pyrrolobenzoxazepinones: novel and specific non-nucleoside HIV-1 reverse transcriptase inhibitors with antiviral activity

Two novel classes of pyrrolobenzothiazepinones and pyrrolobenzoxazepinones were investigated as potential anti-AIDS drugs. These compounds were found to inhibit HIV-1 reverse transcriptase (RT) enzyme in vitro and to prevent HIV-1 cytopathogenicity in T4 lymphocytes, without appreciable activity on HIV-2 cytopathic effects, and against HBV as well as calfthymus DNA alpha-polymerase. Their potency is influenced by substituents at position 6 and on the fused aromatic ring. Specifically, small lipophilic substituents at C-6 were preferred, whereas substitutions on the benzo-fused ring were found to be detrimental to activity, with respect to the unsubstituted compounds. Modification of the pie-system at C-6 is well tolerated, although the replacement of the benzo-fused with a [2,3]naphtho-fused ring leads to a less active compound. Maximum potency and specificity is achieved with a phenyl and an ethyl group at position 6 of the pyrrolobenzoxazepinone system. In the enzymatic assay the oxazepinone derivative (+/-)-6-ethyl-6-phenylpyrrolo[2,1-d][1,5] benzoxazepin-7(6H)-one 16e (IC50 = 0.25 microM) was found to be more potent than nevirapine (IC50 = 0.5 microM), tested in the same experimental conditions using rC.dG as a template-primer. In cell culture assay benzoxazepine 16e was active against HIV-1, both wild type and AZT-sensitive, and HIV-1 (IIIB) strains, but not against HIV-2. In enzyme assay although 16e inhibited HIV-1 RT, it was inactive against the nevirapine-resistant recombinant RT Y181C at 50 microM. Molecular modeling studies suggest that these derivatives present a 3D pharmacophoric arrangement similar to that of other non-nucleoside inhibitors such as nevirapine.