Time-dependent expression of ryanodine receptors in sea urchin eggs, zygotes and early embryos.

In this work, the presence of calcium-dependent calcium channels and their receptors (RyR) has been investigated in Paracentrotus lividus eggs and early embryos, from unfertilized egg to four-blastomere stages. Electrophysiological recordings of RyR single-channel current fluctuations showed that RyRs are functional during the first developmental events with a maximum at zygote stage, c. 40 min after fertilization, corresponding to the first cleavage. The nature of vertebrate-like RyRs active at this stage was established by specific activation/blockade experiments.

Modulation by internal protons of native cyclic nucleotide-gated channels from retinal rods.

Ion channels directly activated by cyclic nucleotides are present in the plasma membrane of retinal rod outer segments. These channels can be modulated by several factors including internal pH (pH(i)). Native cyclic nucleotide-gated channels were studied in excised membrane patches from the outer segment of retinal rods of the salamander. Channels were activated by cGMP or cAMP and currents as a function of voltage and cyclic nucleotide concentrations were measured as pH(i) was varied between 7.6 and 5.0. Increasing internal proton concentrations reduced the current activated by cGMP without modifying the concentration (K(1/2)) of cGMP necessary for half-activation of the maximal current. This effect could be well described as a reduction of single-channel current by protonation of a single acidic residue with a pK(1) of 5.1. When channels were activated by cAMP a more complex phenomenon was observed. K(1/2) for cAMP decreased by increasing internal proton concentration whereas maximal currents activated by cAMP increased by lowering pH(i) from 7.6 to 5.7-5.5 and then decreased from pH(i) 5.5 to 5.0. This behavior was attributed both to a reduction in single-channel current as measured with cGMP and to an increase in channel open probability induced by the binding of three protons to sites with a pK(2) of 6.

A point mutation in the pore region alters gating, Ca(2+) blockage, and permeation of olfactory cyclic nucleotide-gated channels.

Upon stimulation by odorants, Ca(2+) and Na(+) enter the cilia of olfactory sensory neurons through channels directly gated by cAMP. Cyclic nucleotide-gated channels have been found in a variety of cells and extensively investigated in the past few years. Glutamate residues at position 363 of the alpha subunit of the bovine retinal rod channel have previously been shown to constitute a cation-binding site important for blockage by external divalent cations and to control single-channel properties. It has therefore been assumed, but not proven, that glutamate residues at the corresponding position of the other cyclic nucleotide-gated channels play a similar role. We studied the corresponding glutamate (E340) of the alpha subunit of the bovine olfactory channel to determine its role in channel gating and in permeation and blockage by Ca(2+) and Mg(2+). E340 was mutated into either an aspartate, glycine, glutamine, or asparagine residue and properties of mutant channels expressed in Xenopus laevis oocytes were measured in excised patches. By single-channel recordings, we demonstrated that the open probabilities in the presence of cGMP or cAMP were decreased by the mutations, with a larger decrease observed on gating by cAMP. Moreover, we observed that the mutant E340N presented two conductance levels. We found that both external Ca(2+) and Mg(2+) powerfully blocked the current in wild-type and E340D mutants, whereas their blockage efficacy was drastically reduced when the glutamate charge was neutralized. The inward current carried by external Ca(2+) relative to Na(+) was larger in the E340G mutant compared with wild-type channels. In conclusion, we have confirmed that the residue at position E340 of the bovine olfactory CNG channel is in the pore region, controls permeation and blockage by external Ca(2+) and Mg(2+), and affects channel gating by cAMP more than by cGMP.

Mechanisms of modulation by internal protons of cyclic nucleotide-gated channels cloned from sensory receptor cells.

We have examined the modulation by internal protons of cyclic nucleotide-gated (CNG) channels cloned from bovine olfactory receptor cells and retinal rods. CNG channels were studied in excised inside-out membrane patches from Xenopus laevis oocytes previously injected with the mRNA encoding for the subunit 1 of olfactory or rod channels. Channels were activated by cGMP or cAMP, and currents as a function of cyclic nucleotide concentrations were measured as pHi varied between 7.6 and 5.0. Increasing internal proton concentrations caused a partial blockage of the single-channel current, consistent with protonation of a single acidic site with a pK1 of 4.5-4.7, both in rod and in olfactory CNG channels. Channel gating properties were also affected by internal protons. The open probability at low cyclic nucleotide concentrations was greatly increased by lowering pHi, and the increase was larger when channels were activated by cAMP than by cGMP. Therefore, internal protons affected both channel permeation and gating properties, causing a reduction in single-channel current and an increase in open probability. These effects are likely to be caused by different titratable groups on the channel.

Natural history of neck disease in patients with squamous cell carcinoma of oropharynx and pharyngolarynx.

Out of a series of 2040 patients referred to the Institut Curie with squamous cell carcinoma of oropharynx and pharyngolarynx, 1666 cases were evaluated on admission regarding the characteristic metastases patterns to their cervical lymph nodes. Incidence and topographic distribution of lymph nodes are correlated with the anatomic sites of primary lesions. Biological virulence of these tumors is emphasized since the overall incidence of positive neck nodes attains 63% (1048/1666) and advanced disease, stage IV in the UICC classification, 61%. Cervical status is also related to several characteristics of the primary: clinical staging and variety, and histopathological differentiation. Ipsilateral cervical involvement is characterized by the high incidence of metastases in the jugular chain for the whole series, in the submaxillary group for oropharyngeal carcinomas and in the spinal accessory chain for cancer of the pharyngolarynx (pyriform sinus and lateral epilarynx). Preliminary therapeutic implications are derived from this nodal distribution. Comparisons are established between the 1978 UICC and 1976 AJC classifications, showing a good correlation despite multiple differences in staging criteria. It is shown that assessment combining both the multiplicity and the volume of cervical metastases allows to evaluate more accurately the aggressiveness of the primary.

Co-expression of wild-type and mutant olfactory cyclic nucleotide-gated channels: restoration of the native sensitivity to Ca(2+) and Mg(2+) blockage.

In the pore of homomeric cyclic nucleotide-gated (CNG) channels, Ca(2+) and Mg(2+) bind to a set of glutamate residues, which in the bovine olfactory CNG channel are located at position 340. However, native CNG channels from olfactory sensory neurons are composed by the assembly of three different types of subunits, each having a different residue -- glutamate, aspartate or glycine -- at the position corresponding to the binding site for external Ca(2+) and Mg(2+). We co-expressed the wild-type principal alpha subunit with its mutants E340G and E340D in different combinations in Xenopus laevis oocytes, and measured Ca(2+) and Mg(2+) blockage in excised outside-out membrane patches. The comparison between our results and data from native olfactory CNG channels indicates that the presence of all three residues -- glutamate, aspartate and glycine -- in the different subunits, is necessary to restore the sensitivity to external Ca(2+) and Mg(2+) measured in native channels.

[Breast cancer: histological prognosis from biopsy material]. / Cancer du sein : pronostic histologique sur matériel biopsique.

Two histological factors to be taken into consideration for prognosis in pretreatment schedules of breast cancer have been studied on a group of 352 cases treated by non-mutilating therapeutics at the Fondation Curie between 1960 and 1970. The tumour material the slides of which we have reexamined "blindly", i.e. ignoring the evolution of the case had been obtained mostly by drill-biopsy. Histological groups and types have been determined following an analytical classification for computer purpose. The degree of malignancy was calculated with the method of Scarff-Bloom-Richardson. The analyzed data have been memorized on computer and then confronted with the elements of the T.N.M. classification and the survival of the patients involved. It appeared that if drill-biopsie have been performed correctly the histological type may be defined in eighty percent of cases. And it is likewise possible to calculate the histological grade of malignancy for each mammary cancer. With such a material the value for prognosis by means of the Scarff-Bloom-Richardson method still remains if applied only to adenocarcinoma of the "common infiltrating type".

[Prognostic factors in epitheliomas of the breast]. / Facteurs pronostiques des épithéliomas mammaires.

Prognostic factors in breast carcinoma were studied on material which consisted of 733 patients with a follow-up of over 5 years and on 361 with a follow-up of over 10 years. In the first part of the study the prognostic factors are related to the physical characteristics of the primary tumour such as its situation and size and its relationship to skin and deep tissues. Clinical examination of the axilla, studied in detail, has proved a reliable guide to prognosis. The second part deals with such factors as age, hormonal status, age at first pregnancy and parity. A critical analysis of the T.N.M. classification ends the study, with special reference to the prognostic factors which relate to the primary tumour.

[The effects of parafunctional contacts on the natural dentition]. / Effetti dei contatti parafunzionali sulla dentatura naturale.

The paper analyses the incidence and etiology of bruxism through a review of the literature. The effects that this pathology has on teeth are discussed and there is a brief discussion of therapy.

[Occlusion in the etiology of craniomandibular disorders. Current directions]. / L'occlusione nell'etiologia dei disordini cranio-mandibolari. Orientamenti attuali.

Craniomandibular disorders are a pathology with a multifactorial genesis where the aetiological aspects it represented by emotional and occlusal factors. These provoke muscular hyperactivity so determining a change in all components of the stomatognathic apparatus. A critical analysis of the literature leads to an analysis of the importance of the occlusal factor in the aetiology of MCD. The conclusions reached are that the ideal occlusion is a theoretical concept. Physiological occlusion is the situation in which, independently of the number, lay-out and relationship between teeth there exists a subjective occlusal stability and a satisfactory masticatory, phonatory and aesthetic function.

The permeability of the cGMP-activated channel to organic cations in retinal rods of the tiger salamander.

1. The permeability of the channel activated by guanosine 3',5'-cyclic monophosphate (cGMP) to many organic monovalent cations was determined by recording macroscopic currents in excised inside-out patches of plasma membrane from isolated retinal rod outer segments of the tiger salamander. 2. Current-voltage relations were measured when the NaCl of the bathing medium was replaced by salts of organic cations. Permeability ratios relative to Na+ ions were calculated with the Goldman-Hodgkin-Katz potential equation from the measured changes of reversal potentials. 3. Hydroxylammonium+, hydrazinium+ and methylammonium+, which are molecules of very similar shape and size, permeate the channel with very different permeability ratios: 5.92, 1.99 and 0.60 respectively. 4. Methylated and ethylated ammonium+ compounds were investigated. It was found that, not only methylammonium+, but also dimethylammonium+ and ethylammonium+ were permeant with permeability ratios of 0.6, 0.14 and 0.16 respectively. Trimethylammonium+, tetramethylammonium+, diethylammonium+, triethylammonium+, and tetraethylammonium+ were not permeant. 5. Guanidinium+ and its derivatives formamidinium+, aminoguanidinium+, acetamidinium+ and methylguanidinium+ were all permeant with permeability ratios 1.12, 1.00, 0.63, 0.36 and 0.33 respectively. 6. The cGMP-activated channel was found to be permeable to at least thirteen organic cations. Molecular models of the permeant cations indicate that the cross-section of the narrowest part of the pore must be at least as large as a rectangle of 0.38 x 0.5 nm dimensions.

The relation between stimulus and response in olfactory receptor cells of the tiger salamander.

1. Olfactory receptor cells were isolated from the adult tiger salamander Ambystoma tigrinum and the current in response to odorant stimuli was measured with the whole-cell voltage-clamp technique while odorants at known concentrations were rapidly applied for controlled exposure times. 2. Three odorants, cineole, isoamyl acetate and acetophenone, were first applied at 5 x 10(-4) M. Out of forty-nine cells tested, 53% responded to one odorant only, 22% to two odorants and 25% to all three odorants. 3. The amplitude of the current in response to a given odorant concentration was found to be dependent on the duration of the odorant stimulus and reached a saturating peak value at 1.2 s of stimulus duration. 4. The current measured at the peak of the response for odorant steps of 1.2 s as a function of odorant concentration was well described by the Hill equation for the three odorants with Hill coefficients higher than 1 and K1/2 (odorant concentration needed to activate half the maximal current) ranging from 3 x 10(-6) to 9 x 10(-5) M. 5. It is concluded that olfactory receptor cells are broadly tuned and have a low apparent affinity for odorants, integrate stimulus information over time, and have a narrow dynamic range.

Quantal-like current fluctuations induced by odorants in olfactory receptor cells.

Many sensory systems have evolved signal detection capabilities that are limited only by the physical attributes of the stimulus. For example, 'hair' cells of the inner ear can detect displacements of atomic dimensions. Likewise, both in vertebrates and in invertebrates photoreceptors can detect a single photon. The olfactory stimulus also has a quantal unit, the single odorant molecule. Insects are reportedly able to detect a single pheromone molecule, whereas quantal responses in vertebrate olfactory receptor cells have not been reported yet. Psychophysical measurements indicate that a minimum of 50 odorant molecules are necessary for human olfactory detection, suggesting that an individual receptor may be activated by a single odorant molecule. We report here measurements of current fluctuations induced by odorants that suggest a quantal event of about 0.3-1 pA, presumably triggered by the binding of a single odorant molecule.

[Psychopharmacologic prescription at a public service. Examination of a group of patients admitted to the psychiatric service of diagnosis and therapy]. / La prescrizione psicofarmacologica in un servizio pubblico. Esame di un gruppo di pazienti ricoverati in SPDC.

The use of psychodrugs in patients admitted to an SPDC over a period of thirty days is considered. During this period two questionnaires were administered, addressed respectively to the nursing staff and their patients. The purpose of the questionnaires was to investigate experience relative to the psychodrug on the part of the patient and the nurse who administers it. The results tend to confirm basic hypotheses: the psychodrug often takes on meanings that go beyond pure biochemical action to become mediators of complex, significant relational exchanges. Precaution in the of the psychodrug must therefore consider biological side-effects as well as relational ones.

[Inflammatory aneurysm of the abdominal aorta and ureteral obstruction]. / Inflammatorisches Bauchaortenaneurysma und Ureterobstruktion.

The incidence of inflammatory abdominal aortic aneurysm (IAAA) is reported in between 5 and 15% of all cases of abdominal aortic aneurysms (AAA). As a diagnostic hint the CT- or MRI-scan shows the ureters typically displaced medially, caused by a simultaneously visible retroperitoneal perianeurysmal fibrosis. In IAAA, one has to expect about 25% ureteral congestion, uni- or bilateral. Since the probability of rupture of IAAA--in the natural course between 15 and 25% of the cases--does not apparently differ much from the arteriosclerotic AAA, the operative aorto-iliac reconstruction with bypass grafting is the only solution and procedure of choice. Postoperatively, renal insufficiency caused by congestion normalizes: long-term follow-up by CT-scanning demonstrates the regression of both retroperitoneal fibrotic process and ureteral entrapment. Therefore, the dangerous ureterolysis results to be unnecessary. Hydronephrosis due to ureteral obstruction following aorto-iliac bypass grafting, if progressive or symptomatic, should be treated first non-operatively by ureteral splint.

Relation between time-dose and local control of operable breast cancer treated by tumorectomy and radiotherapy or by radical radiotherapy alone.

67 patients with tumors 3 cm or less and with negative axilla, who had lumpectomy and radiotherapy, and 122 patients with larger tumors or clinically positive axilla, who had radical radiotherapy without prior lumpectomy, were evaluated at five years to determine the optimum dose for local control. 7000 rad in seven to eight weeks controlled 85% of lumpectomy cases, whereas 8000 rad in 81/2 weeks were required to control two-thirds of cases treated by radical irradiation alone. Subclinical (N0, N1a) and clinical disease (N1b) in the axilla was controlled, in a very high percentage, when 6000 and 7000 rad were delivered, respectively. Dose response curves were obtained for clinical disease in the breast and axilla. No such response was elicited for subclinical disease. Undifferentiated cancers had higher recurrence rates than well differentiated tumors. Radiation fibrosis in lumpectomy cases was insignificant, whereas 10% of radically irradiated patients had fibrosis of the breast.