The suppression of star formation by powerful active galactic nuclei.

The old, red stars that constitute the bulges of galaxies, and the massive black holes at their centres, are the relics of a period in cosmic history when galaxies formed stars at remarkable rates and active galactic nuclei (AGN) shone brightly as a result of accretion onto black holes. It is widely suspected, but unproved, that the tight correlation between the mass of the black hole and the mass of the stellar bulge results from the AGN quenching the surrounding star formation as it approaches its peak luminosity. X-rays trace emission from AGN unambiguously, whereas powerful star-forming galaxies are usually dust-obscured and are brightest at infrared and submillimetre wavelengths. Here we report submillimetre and X-ray observations that show that rapid star formation was common in the host galaxies of AGN when the Universe was 2-6 billion years old, but that the most vigorous star formation is not observed around black holes above an X-ray luminosity of 10(44) ergs per second. This suppression of star formation in the host galaxy of a powerful AGN is a key prediction of models in which the AGN drives an outflow, expelling the interstellar medium of its host and transforming the galaxy's properties in a brief period of cosmic time.

Submillimetre galaxies reside in dark matter haloes with masses greater than 3 × 10(11) solar masses.

The extragalactic background light at far-infrared wavelengths comes from optically faint, dusty, star-forming galaxies in the Universe with star formation rates of a few hundred solar masses per year. These faint, submillimetre galaxies are challenging to study individually because of the relatively poor spatial resolution of far-infrared telescopes. Instead, their average properties can be studied using statistics such as the angular power spectrum of the background intensity variations. A previous attempt at measuring this power spectrum resulted in the suggestion that the clustering amplitude is below the level computed with a simple ansatz based on a halo model. Here we report excess clustering over the linear prediction at arcminute angular scales in the power spectrum of brightness fluctuations at 250, 350 and 500 µm. From this excess, we find that submillimetre galaxies are located in dark matter haloes with a minimum mass, M(min), such that log(10)[M(min)/M(⊙)] = 11.5(+0.7)(-0.2) at 350 µm, where M(⊙) is the solar mass. This minimum dark matter halo mass corresponds to the most efficient mass scale for star formation in the Universe, and is lower than that predicted by semi-analytical models for galaxy formation.

[Diagnostic value of the assay of beta 2 microglobulin during the monitoring of surgically-treated colorectal cancers. Comparison with carcinoembryonic antigen]. / Valeur diagnostique du dosage de la beta 2-microglobuline au cours de la surveillance des cancers colo-rectaux opérés. Comparaison avec l'antigéne carcino-embryonnaire.

This work presents an evaluation of the diagnostic value of seric beta 2-microglobulin in the follow-up of operated colorectal cancers. Ninety-one patients were operated on with a curative intent between 1976 and 1979. These patients were followed for at least 2 years and divided in 2 groups: a) group NR: 48 patients apparently free of loco-regional recurrence and of distant metastases, b) group R: 43 patients presenting a cancerous relapse. High levels of beta 2-microglobulin were found in 21 patients of group NR (specificity: 56 p. 100) and in 25 patients of group R (sensitivity: 58 p. 100). In the same population, the specificity and the sensitivity of carcinoembryonic antigen (CEA) for the diagnosis of a relapse were 92 p. 100 and 88 p. 100 respectively. No significant statistical correlation was observed between the levels of beta 2-microglobulin and CEA. The sensitivity of the association beta 2-microglobulin + CEA was not superior to the dosage of CEA alone despite its reduced specificity (54 p. 100). These results indicate that the diagnostic value of the dosage of beta 2-microglobulin is inferior to that of CEA and is without interest for the detection of tumoral recurrence in the postoperative follow-up of colorectal cancers.

[Malignant melanomas of Lille 1967-1972. Comparison between "histoprognosis" and actual outcome (author's transl)]. / Mélanomes malins lillois 1967-1872. Confrontation entre l'histopronostic et le devenir réel

This work groups 126 cases of malignant melanomas operated since 1967. Seventy-seven cases responding to 2 criterions were selected: reexamination of the primary pathologic sample of melanoma according to 4 tests of histoprognosis and adequate follow-up of the patient. Histoprognostic criterions according to Clark and Mihm were the histogenetic type, the level of invasion plus vascular embolic neoplastic invasion and the notion of mitotic index. Four main conclusions emerged: Statistical notion of a critical period situated between the 12th and 30th month, during which 40% of patients die, especially those with primary tumor of histogenetic type NM (nodular melanoma) or SSM (superficial spreading melanoma) and invasion stage IV and V. Assurance of the value of histoprognosis in the primary cognition of tumoral determinism. A new precision in the decision of systematic node excision in invasion stages IV and V, and in stages III with high mitotic index. Reasonable and early use of all therapeutic means in cases with unfavourable histoprognosis.

[Early postoperative intestinal obstructions. Contribution of radiography to diagnosis of the type and to the indication for reoperation (experience in 84 cases)]. / Occlusions post-opératoires précoces. Apport de la radiographie au diagnostic de variété et à l'indication de réintervention. (Expérience de 84 observations)

The authors report 84 cases of post-operative intestinal obstruction and demonstrate the value of straight XRays and barium meal in the diagnosis of the variety of early post-operative obstruction and the indications for operation. In 74 cases out of 82, a precise diagnosis of the mechanical or paralytic nature of the obstruction was made and the operation always carried out under best possible conditions.

[Massive pulmonary embolism due to post-traumatic pseudo-aneurysm due to rupture of the left hepatic artery, revealed by dissecting aneurysm below the capsule of the right lobe of the liver (author's transl)]. / Embolie pulmonaire massive due à un pseudo-anévrysme post-traumatique rompu de l'artère hépatique gauche, révélé par un hématome disséquant et sous-capsulaire du foie droit.

We report a case of trauma of the left lobe of the liver causing left centro-hepatic contusion (stage III) revealed by infective jaundice. Secondarily, the appearance of a right subcapsular hematoma corrected the diagnosis, permitting the authors to proceed to angiographic exploration and consider operation on the right side, but the patient had a massive pulmonary embolism. This case recalls the diagnostic difficulties soon after a contusion, the diffusion of a hematoma under pressure from left to right, then from the liver towards the hepatic venous system, the risk of pulmonary embolism, from an aneurysm of the hepatic artery.

[Parathyroid risk in thyroid surgery. Reality and prevention. 502 bilateral thyroidectomies]. / Le risque parathyroïdien en chirurgie thyroïdienne. Sa réalité et sa prévention. 502 exérèses bilatérales.

Prospective study of parathyroid risk in a bulk of 502 consecutive bilateral thyroidectomies. Early post-operative hypocalcemia has been documented in 8,8% of the patients, but persisted in only 1,6% one year later. Late parathyroid risk of total thyroidectomy is 3,3% but increases twofold if neck dissection is simultaneously performed. Methods of this study probably misdiagnose a number of mild hypoparathyroidism. Lack of early hyperphosphoremia seems to be an optimizing criteria for aftermath. In Grave's disease, early post-operative hypocalcemia is more common (6,9%) but often subsides (definitive risk: 0,4%). This acceptable morbidity is compared to the data of literature. To prevent post-operative hypoparathyroidism a painstaking dissection of parathyroid blood supply seems more promising and effective than routine autotransplantation of the glands.

[Advantages of systematic recurrent laryngeal nerve resection during thyroid surgery. Results of 422 thyroidectomies employing this procedure (author's transl)]. / Valeur de la dissection systématique du nerf récurrent en chirurgie thyroïdienne: 428 thyroäidectomies en 1978.

Thyroidectomy for different thyroid disorders was conducted in 422 patients during 1978, after normal pre-operative laryngoscopy findings. Dissection of the recurrent laryngeal nerve was employed systematically in all patients except those having isthmectomy or enucleation operations, with a total number of 556 nerves dissected. Pre-and post-operative laryngoscopic examinations in the alert patient was conducted in all cases. After one year, 8% of the patients with abnormal post-operative laryngoscopic findings had not returned for follow-up. The known rate of recurrent nerve paralysis after one year was 0.7% of the nerves exposed, the maximum rate being 2% if patients not followed-up are included. These results confirm the value of systematic recurrent nerve dissection during thyroid surgery.

[Systematic or selective frozen sections during surgery for suspected malignant thyroid lesions? Results in 674 cases over a period of 6 years (author's transl)]. / Examen extemporané systématique ou sélectif dans la chirurgie des affections thyroïdiennes suspectes de malignité? Expérience de 674 examens en 6 ans.

Results of a retrospective study of 674 frozen sections in thyroid surgery, demonstrated on over all reliability of 98.2%, when compared with final pathological findings, with 651 confirmation in 674 cases. False negatives of malignancy represented 1.6% of lesions thought to be benign, while false positives were obtained in 4.8% of lesions thought to be malignant on frozen sections. Prior to frozen sections, 221 patients had needle punctures and cytological smears studies of the thyroid lesion. When comparing the results after using the two methods, no false positive for malignancy, assessed by cytology, was found on frozen sections, which also corrected but two false negatives of malignancy given by the 177 smears affirmative of benignancy, but reduced the number of equivocal results of cytology from 36 to 1. Both pre-operative cytological examination by needle puncture and intra-operative frozen sections appear, therefore, to be very reliable methods for studying thyroid lesions. Frozen sections are complementary to cytological studies. These results suggest that, in surgical thyroid diseases, frozen sections, need perhaps not to be systematically conducted, but should be selective and reserved for cases in which pre-operative needle cytology affirms malignancy, or raises suspicion.

[Colonic occlusions. Retrospective cooperative study of 497 cases]. / Les occlusions coliques. Etude rétrospective coopérative de 497 cas.

A retrospective multicenter study involving 12 digestive surgery centers was conducted on 497 cases of colon obstruction. The most frequent cause of colon obstruction was colo-rectal cancer (71 p. cent of cases), but many other etiologies were involved, including 61 cases of torsion and 37 patients with occlusive sigmoiditis. Differential clinical and radiological features in each etiological group are discussed, the results of therapy undertaken analyzed, and a reasonable line of conduct proposed, adapted to each situation, with the objective of attempting to reduce mortality which still affects 25 p. cent of cases operated upon.

The detection of a population of submillimeter-bright, strongly lensed galaxies.

Gravitational lensing is a powerful astrophysical and cosmological probe and is particularly valuable at submillimeter wavelengths for the study of the statistical and individual properties of dusty star-forming galaxies. However, the identification of gravitational lenses is often time-intensive, involving the sifting of large volumes of imaging or spectroscopic data to find few candidates. We used early data from the Herschel Astrophysical Terahertz Large Area Survey to demonstrate that wide-area submillimeter surveys can simply and easily detect strong gravitational lensing events, with close to 100% efficiency.