A cyclic carbanionic valence isomer of a carbocation: diphosphino analogs of diaminocarbocations

Diaminocarbocations (or amidinium salts) feature a three-center 4pi electron system with an open planar structure. Their 2pi electron three-membered cyclic valence isomers, in which the carbon atom bears a negative charge, are predicted to be about 541 kilojoules per mole higher in energy than the open form. This isomer has not been identified yet. In contrast, the attempted synthesis of a diphosphorus analog of amidinium salts leads to the cyclic carbanionic form. There is no precedent for such a transformation of a carbocationic center into a carbanionic center, but with the help of heavier main-group elements, numerous examples can be imagined. This approach will enable the preparation of many unknown structural moieties that are difficult or even impossible to access in the corresponding carbon and nitrogen series.

Stable versions of transient push-pull carbenes: extending lifetimes from nanoseconds to weeks

A (phosphanyl)(trifluoromethyl)carbene is shown to be stable for weeks in solution at temperatures up to -30 degrees C. Its chemical behavior exactly matches that of its transient congeners, even to the extent that subtle effects, such as the recently discovered weak pi interaction with aromatics, are observed. The influence of substituents on the structure of push-pull carbenes is demonstrated by a single-crystal x-ray diffraction study of a (phosphanyl)[2, 6-bis(trifluoromethyl)phenyl]carbene. The lifetime of these molecules makes them accessible to a wider range of standard techniques, allowing their chemical and physical behaviors to be studied in more detail than was previously possible.

Evidence that ventrolateral thalamotomy may eliminate the supraspinal component of both pathological and physiological tremors

Ventrolateral (VL) thalamotomy produced a marked reduction of oscillations related to the supraspinal components of Parkinson's disease tremor (4-7 Hz) and physiological tremor (8-12 Hz). Finger tremor was examined in nine patients undergoing unilateral VL thalamotomy and in nine age-matched controls. In comparison to the preoperative state, the relative percentage of power within the 7.6-12.5 Hz band did not increase after the surgical procedure. Furthermore, the amount of absolute power within the 7.6-12.5 Hz band was much lower for post-surgical patients in comparison to matched controls when periods of tremor having equal amplitudes were compared. These results suggest that VL thalamotomy interrupts a common circuit involved in the supraspinal component of both physiological and pathological tremors. We provide evidence that the thalamus may be involved in circuits generating physiological tremor in humans.

PAC1 receptor-deficient mice display impaired insulinotropic response to glucose and reduced glucose tolerance

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a ubiquitous neuropeptide of the vasoactive intestinal peptide (VIP) family that potentiates glucose-stimulated insulin secretion. Pancreatic beta cells express two PACAP receptor subtypes, a PACAP-preferring (PAC1) and a VIP-shared (VPAC2) receptor. We have applied a gene targeting approach to create a mouse lacking the PAC1 receptor (PAC1(-/-)). These mice were viable and normoglycemic, but exhibited a slight feeding hyperinsulinemia. In vitro, in the isolated perfused pancreas, the insulin secretory response to PACAP was reduced by 50% in PAC1(-/-) mice, whereas the response to VIP was unaffected. In vivo, the insulinotropic action of PACAP was also acutely reduced, and the peptide induced impairment of glucose tolerance after an intravenous glucose injection. This demonstrates that PAC1 receptor is involved in the insulinotropic action of the peptide. Moreover, PAC1(-/-) mice exhibited reduced glucose-stimulated insulin secretion in vitro and in vivo, showing that the PAC1 receptor is required to maintain normal insulin secretory responsiveness to glucose. The defective insulinotropic action of glucose was associated with marked glucose intolerance after both intravenous and gastric glucose administration. Thus, these results are consistent with a physiological role for the PAC1 receptor in glucose homeostasis, notably during food intake.

[Case report forum: the example of French sarcoma group multidisciplinary discussion tools. Sarcomes de la FNCLCC]

Within the Rubis 4th framework of European project is led a pilot experiment of tools and services for health professionals in prospect for the Aquitanian healthcare network. The sarcoma group of the FNCLCC (47 people) uses on its web site a multidisciplinary dialogue with a specific discussion forum. This service allows the anonymous publication of a imaging clinical case and to start a take care discussion. 87 cases were published in 13 months involving 261 answers from February 1999 to February 2000. A case is published every 4 days on average and the deadlines for replies regularly drop (15 days in February 1999 down 1.1 day in February 2000). The cases are published either for a diagnosis or treatment request (30%) or for the physical preparation of meeting or for the continuous medical training (70%). There are many advantages in comparison with the other possibilities of discussion: availability, autonomy of publication, cost, number of experts participating. These NTIC services will be developing within the regional healthcare oncology networks and are already tested by other regional groups (Lymphoma) considering the simplicity of use, management and training of the functionality.

Absence of microsatellite instability in transitional cell carcinoma of the bladder

OBJECTIVES

To investigate the prevalence of the microsatellite instability related to mismatch repair (MMR) gene defects using a panel of six microsatellite markers, as recommended by a recent workshop on microsatellite instability in colon cancer, because it is still unclear whether abnormalities in DNA MMR genes are involved in transitional cell carcinoma (TCC) of the bladder.

METHODS

Three mononucleotide repeats (BAT26, TGFbetaRII, and BAX) were studied in 33 TCC samples and in four bladder cancer cell lines. Three dinucleotide repeats (D2S123, D5S346, and D17S250) were studied in 21 of these 33 TCC samples.

RESULTS

No alteration was detected either in the 33 TCC samples analyzed or in the four bladder cancer cell lines (T24, J82, 647V, and 1207) studied. A difference between normal and tumor DNA was observed in only 1 of 21 tumor samples for D17S250.

CONCLUSIONS

These data indicate that microsatellite instability is very uncommon in TCC of the bladder.

New Types of Stable Aldehydes: Formylphosphane and Formylphosphane Oxide

The reactivity of the formyl group in alpha-phosphorus-substituted aldehydes 1 can be tuned by adjusting the coordination number of the phosphorus atom. When X is a lone pair, the formylphosphanes obtained are stable compounds, whereas when X=O a relatively unstable formylphosphane oxide is produced. R=iPr(2)N, cHex(2)N.

Metastatic gastric cancer arising from breast carcinoma: endoscopic ultrasonographic aspects

Linitis plastica of the stomach was diagnosed in four patients. Endoscopic ultrasonography (EUS) was performed in four cases; they were monitored by EUS and had their treatment adapted accordingly. According to the present study, the typical criteria of gastric linitis at EUS are: (a) rigidity of the gastric wall; (b) a wall thickness exceeding 6 mm; (c) a second enlarged layer marginally more echogenic than the fourth hypoechogenic layer (muscularis propria); (d) a third hyperechogenic enlarged layer; and (e) a poor demarcation between layers. Gastric linitis appears more likely to be specific metastasis from lobular breast carcinoma. In most of the follow-up cases, EUS showed correlation with a subsequent decrease of the CA15.3 level. At present, EUS seems to be the most effective and least invasive examination for clinical diagnosis and treatment surveillance of secondary gastric linitis arising from infiltrating lobular carcinoma (ILC) of the breast.

Drug evaluation of concurrent Pneumocystis carinii, Toxoplasma gondii, and Mycobacterium avium complex infections in a rat model

We present a new experimental model for the simultaneous evaluation of the activities of drugs against Pneumocystis carinii, Toxoplasma gondii, and Mycobacterium avium complex infections. Rats latently infected with P. carinii were challenged with the MO-1 strain of M. avium and then immunosuppressed with corticosteroids for 7 weeks. At week 5 the RH strain of T. gondii was intraperitoneally injected. Organs were examined for the three pathogens after death or killing of the animals at week 7. Without treatment, rats challenged with T. gondii died with pulmonary P. carinii infection and disseminated T. gondii and M. avium infections. In order to assess the value of the model for evaluation of the activities of drugs, we administered by oral gavage for 7 weeks drugs or combinations of drugs selected for their individual efficacies against at least one pathogen. We found that clarithromycin with sulfamethoxazole, clarithromycin with atovaquone, roxithromycin with sulfamethoxazole or dapsone, and rifabutin with atovaquone were effective against the three infections, whereas PS-15 with dapsone and trimethoprim with sulfamethoxazole were active against Toxoplasma and Pneumocystis infections only. This triple-infection rat model offers a new tool for the simultaneous evaluation of the activities of drugs against three of the major opportunistic infections occurring in immunosuppressed individuals.

Isolation of a benzene valence isomer with one-electron phosphorus-phosphorus bonds

A tetraphosphabenzene analog of the postulated anti-tricyclohexylene, a singlet biradical valence isomer of benzene, has been isolated. The tricyclic derivative features one-electron phosphorus-phosphorus bonds, which result from the pi*-pi* interaction between two diphosphirenyl radicals. Such one-electron bonds may play a wider role in phosphorus chemistry.

Comparative effects of adenosine-5'-triphosphate and related analogues on insulin secretion from the rat pancreas

Adenosine tri- and diphosphate (ATP and ADP) and their structural analogues stimulate insulin secretion from the isolated perfused rat pancreas, an effect mediated by P2Y-purinoceptor activation. Concerning the base moiety of the nucleotide, it was previously shown that purine but not pyrimidine nucleoside triphosphates were active and that substitution on purine C2 with the 2-methylthio group greatly enhanced the potency. In this study, we further analyze the consequences of ribose and polyphosphate chain modifications. Modifications in 2' and 3' position on the ribose led to a decrease in insulin response when bulky substitutions were made: indeed, 2'-deoxy ATP was similar in activity to ATP, whereas arylazido-aminopropionyl ATP (ANAPP3) was weakly effective and trinitrophenyl ATP (TNP-ATP) was inactive. Substitution on the gamma phosphorus of the triphosphate chain led to a decrease (gamma-anilide ATP) or no change (gamma-azido ATP) in potency; the replacement of the bridging oxygen between beta and gamma phosphorus by a peroxide group did not significantly change the activity, whereas substitution by a methylene group completely abolished stimulation of insulin secretion. As for the phosphorothioate analogues, adenosine-5'-O-(3-thiotriphosphate) (ATP gamma S) induced an insulin response similar to that produced by ATP, whereas adenosine-5'-O-(2-thiodiphosphate) (ADP beta S) was about 100-fold more potent than ATP, as previously shown. In conclusion, two structural features seem to have a strategic importance for increasing the insulin secretory activity of ATP analogues: substitution at the C2 position on the adenine ring of ATP and modifications of the polyphosphate chain at the level of the beta phosphorus.

Meningeal melanocytoma. Report of a case and a historical comparison

Meningeal melanocytomas are rare tumors of the central nervous system that are found almost exclusively in the posterior fossa and spinal cord and whose natural history is poorly defined. In this report, the authors review the clinical presentation, radiological appearance, operative findings, and histological features in two cases of meningeal melanocytoma: one cranial and one spinal. Two women, aged 21 and 30 years, were admitted to the hospital 60 years apart: the first because of progressive paraplegia and the second because of slowly progressive hearing loss. The first patient had an extradural tumor that was treated by laminectomy, subtotal resection, and postoperative radiotherapy in 1936. Her symptoms recurred 16 years later and she underwent reoperation of the residual tumor, which was found to have an intradural component. The authors' patient, who presented 60 years later, underwent plain and enhanced computerized tomography and magnetic resonance imaging that demonstrated a large posterior fossa lesion indicative of either an acoustic neuroma or a meningioma. She underwent posterior fossa decompression but only partial excision of the tumor could be accomplished because vigorous bleeding limited the extent of the resection. Surgery was followed by radiotherapy. The residual tumor enlarged despite these measures and required repeated resection 6 months later. At the second operation the tumor was much less vascular, perhaps reflecting the effects of radiotherapy, and was removed almost entirely. The patient died 6 months later from an anticoagulant-related cerebellar hemorrhage. In both cases the lesions were jet black, and histological examination revealed melanin-containing hypercellular tumors with rare mitotic figures. Meningeal melanocytomas are being diagnosed with increased frequency in parallel with improvements in neuroimaging and clarification of histological features. Clinical presentation of patients with these tumors typically occurs in their fifth decade and women are affected twice as often as men. The posterior fossa lesions can mimic acoustic neuromas and meningiomas in location and radiological appearance; however, the internal auditory canal is normal. In the spine, meningeal melanocytomas present with the clinical features of myeloradiculopathy. Diagnosis is made intraoperatively from the gross, jet-black appearance of the tumor and from histological examination. Vascularity, size, and location may render complete resection unfeasible. Because of the tumor's propensity to recur, radiotherapy has been recommended but its role remains to be elucidated.

Arthur Roland Elvidge (1899-1985): contributions to the diagnosis of brain tumors and cerebrovascular disease

The contributions of Arthur Elvidge (1899-1985), Wilder Penfield's first neurosurgical recruit, to the development of neurosurgery have been relatively neglected, although his work in brain tumors extended the previous work of Percival Bailey and Harvey Cushing. He published rigorous correlations of clinical and histological information and formulated a revised, modern nosology for neuroepithelial tumors, including a modern histological definition of glioblastoma multiforme. Well ahead of his time, he believed that glioblastoma was not strictly localized and was the first to comment that the tumor frequently showed "satellitosis." He was the first neurosurgeon in North America to use angiography as a radiographic aid in the diagnosis of cerebrovascular disease. Having studied with Egas Moniz, he was the first to detail the use of angiographic examinations specifically for demonstrating cerebrovascular disorders, believing that it would make possible routine surgery of the intracranial blood vessels. Seeking to visualize all phases of angiography, he was the impetus behind the design of one of the first semi-automatic film changers. Elvidge and Egas Moniz made the first observations on thrombosis of the carotid vessels independently of each other. Elvidge elucidated the significance of embolic stroke and commented on the ischemic sequelae of subarachnoid hemorrhage. Besides his contributions to neurosurgery, he codiscovered the mode of transmission of poliomyelitis. Elvidge's soft-spoken manner, his dry wit and candor, mastery of the understatement, love of exotic travel, and consummate dedication to neurosurgery made him a favorite of patients, neurosurgery residents, nurses, and other hospital staff. His accomplishments and example as teacher and physician have become part of neurosurgery's growing legacy.

[Intra-nodal palisading leiomyoblastoma expression HMB 45]

With a follow up of 14 years, a benign intra nodal palissading smooth muscle tumor is reported as an original lesion because of the expression of HMB 45. This antibody is now well known to be expressed by non melanocytic smooth muscle lesions, like angiomyolipoma, "sugar tumors" of the lung, pulmonary lymphangiomyomatosis and some others, often linked to tuberous sclerosis. The case reported seems to be a new member of the merging concept of "Perivascular Epithelioid Cells (PEC)".

Flow cytometric DNA content analysis of 185 soft tissue neoplasms indicates that S-phase fraction is a prognostic factor for sarcomas. French Federation of Cancer Centers (FNCLCC) Sarcoma Group

BACKGROUND

The authors determined the flow cytometric (FCM) DNA characteristics of 53 benign tumors and 132 malignant (71 primary, 61 recurrent) soft tissue sarcomas to investigate their heterogeneity and to evaluate the prognostic values of DNA ploidy status and S-phase fraction (SPF).

METHODS

One to 11 frozen samples were collected from 185 tumors at 10 participating centers of the French Federation of Cancer Centers (FNCLCC). All FCM analyses were performed in the same laboratory. Histologic diagnoses were collegially reviewed, and grade was assessed by the pathologists of the FNCLCC Sarcoma Group. Relationships between FCM, clinical, and pathologic data were investigated using univariate and multivariate analyses for risks of mortality and metastasis.

RESULTS

All except 2 of the 53 benign lesions were DNA diploid. One schwannoma and one desmoid tumor exhibited small abnormal DNA peaks. SPF was low in all benign lesions. One-third of the sarcomas were DNA diploid, whereas two-thirds were DNA aneuploid. Relationships were found between aneuploidy and mitotic count, grade, and histologic subtype of malignant fibrous histiocytoma. DNA ploidy status did not influence the clinical outcome. Multiple sampling performed in 32 sarcomas showed both diploid and aneuploid samples in 6 tumors. Heterogeneity was related to tumor size. SPF evaluated in 85 sarcomas was related to DNA ploidy status, mitotic count, and grade. SPF > or = 4% was significantly associated with a low overall survival rate. In a multivariate analysis performed for the whole group of 132 patients, the single factors with independent prognostic value for patient mortality were disease free status after the treatment course (P < 0.0001) and SPF (P = 0.03). In the subgroup of patients who were initially free of metastases and free of tumor after the treatment course, SPF remained the only factor that significantly influenced the overall survival rate (P = 0.021).

CONCLUSIONS

Despite its high failure rate, SPF is an independent factor in the prognosis of soft tissue sarcoma and should be considered when patients with a high mortality risk need to be selected for adjuvant chemotherapy.

Antazoline increases insulin secretion and improves glucose tolerance in rats and dogs

In vivo effects of an imidazoline devoid of alpha2-adrenoceptor antagonistic properties, antazoline, on insulin secretion and glycemia were investigated both in fasted rats and dogs. In both species, antazoline (1.5 mg/kg i.v.) transiently increased insulinemia without affecting basal plasma glucose levels. In contrast, during an i.v. glucose tolerance test, antazoline markedly potentiated insulin release and thus increased the glucose disappearance rate. In rats, during an oral glucose tolerance test, the intragastric administration of antazoline (1.5 mg/kg) clearly enhanced insulin secretion and reduced hyperglycemia. In dogs provided with a venous pancreatico-duodenal bypass, antazoline (0.5 mg/kg i.v.) induced an immediate and transient increase in insulin and somatostatin but not in glucagon pancreatico-duodenal outputs. In conclusion, intravenously and orally administered, the imidazoline antazoline is able to stimulate insulin secretion in vivo and improve glucose tolerance. The imidazoline compounds could therefore have a potential therapeutic relevance as new antihyperglycemic insulinotropic agents.

[Granulocytic sarcoma of the testis without hematological manifestations]

A 30-year-old man with a testicular tumor ressembling a "round cell sarcoma" was treated for rhabdomyosarcoma. Complete remission was achieved but the patient relapsed and died of the disease. A retrospective diagnosis of granulocytic sarcoma was established using an anti-myeloperoxidase antibody, unfortunately not available at the time of the initial diagnosis. No hematological disorders were observed during the course of the disease. Four cases of granulocytic sarcoma of the testis have been reported in the literature. All these cases where accompanied or followed by leukemia. The present case seems to be the first case of granulocytic sarcoma of the testis not accompanied by hematological disorders.

Pancreastatin modulates glucose-stimulated insulin secretion from the perfused rat pancreas

Pancreastatin is known to be produced in islet B cells and to inhibit insulin secretion. In this study, we examined whether the peptide affects insulin secretion from the perfused rat pancreas during raising or lowering the glucose concentration within the physiological range. We found that synthetic porcine pancreastatin (15 nmol L-1) significantly inhibited the first phase (5 min) of insulin release induced by raising the glucose concentration from 4.2 to 8.3 mmol L-1 (P < 0.05) without affecting the second phase. Furthermore, the fall in insulin secretion induced by lowering the glucose concentration from 8.3 to 5.5 mmol L-1 was significantly exaggerated in presence of pancreastatin during the first 5 min (P < 0.05). In contrast, pancreastatin did not affect the inhibition of insulin secretion induced by either the alpha 2-adrenoceptor agonist, clonidine (2 nmol L-1), or the P1-purinoceptor (A1-subtype) agonist, N6 (+)-phenylisopropyladenosine (D-PIA) (1.65 mumol L-1). In conclusion, our results show that pancreastatin is a modulator of the early changes in insulin secretion after increase or decrease of the glucose concentration within the physiological range. This suggests that pancreastatin is a modulator of glucose-stimulated insulin secretion.

Influence of Pneumocystis carinii on nitrite production by rat alveolar macrophages

Nitrite production by rat alveolar macrophages was studied to determine the role of L-arginine oxidation in the interaction between these cells and Pneumocystis carinii. Alveolar macrophages from rats obtained from two different breeders were used: rats from Janvier breeder had latent P. carinii infection, while those from Charles River breeder were bred in a germ-free environment. Pneumocystis carinii increased in vitro nitrite generation by unstimulated alveolar macrophages from Janvier rats only, and this was blocked by NG-monomethyl-L-arginine. Incubation of cells from Janvier and Charles River rats with lipopolysaccharide and/or interferon-gamma increased nitrite production to a similar extent. Pneumocystis carinii partially decreased nitrite release by activated alveolar macrophages, and this was still inhibited by NG-monomethyl-L-arginine. In the presence of P. carinii, superoxide dismutase used as a superoxide anion scavenger had no effect on nitrite production by activated cells. These results show that prior exposure to P. carinii leads to nitric oxide production by rat alveolar macrophages. Although the magnitude of this production seems to be moderate, it is of biological significance since cells of P. carinii-naive rats do not generate nitrite whereas those of latently infected rats do.

Agmatine is not a good candidate as endogenous ligand for imidazoline sites of pancreatic B cells and vascular bed

In order to determine whether agmatine could be a putative endogenous ligand for imidazoline receptors mediating insulin secretion and vasoconstriction, we compared its effects with those of the imidazoline, efaroxan. Agmatine exhibited a much lower potency and efficacy than efaroxan on insulin secretion from rat pancreas perfused with 8.3 mM glucose. On the other hand, in contrast to efaroxan (100 microM), agmatine (3 mM) did not increase arginine-induced insulin release. In addition, agmatine failed to reproduce the vasoconstrictor effect of efaroxan on pancreatic vessels. These results show that agmatine does not behave like efaroxan, an agonist for the imidazoline receptors mediating insulin secretion or vasoconstriction in the pancreas.

Differential nitric oxide (NO) production by macrophages from mice and guinea pigs infected with virulent and avirulent Legionella pneumophila serogroup 1

L-arginine-dependent reactive nitrogen intermediates have been identified as macrophage cytotoxic effector molecules against intracellular pathogens. To determine its role, ex vivo production of NO by peritoneal macrophages of C3H/HeN mice and Dunkin-Hartley guinea pigs infected intraperitoneally with a virulent and isogenic avirulent Legionella pneumophila serogroup 1 strain was compared with bacterial clearance from the lungs. While the virulent strain was cleared from mice lungs, the guinea pigs died within 96 h. In vivo infection with both strains resulted in the production of NO by mouse peritoneal macrophages ex vivo. In contrast, guinea pig macrophages did not produce detectable NO. In addition, infection by the avirulent strain led to the production of significantly more NO by mouse macrophages than the virulent parent strain, irrespective of stimulation with lipopolysaccharide (LP) and/or interferon-gamma (ifn-gamma). These results suggest that resistance to Leg. pneumophila infection may depend on the production of NO by host macrophages.