Abundant hydrocarbons in the disk around a very-low-mass star.

Very-low-mass stars (those less than 0.3 solar masses) host orbiting terrestrial planets more frequently than other types of stars. The compositions of those planets are largely unknown but are expected to relate to the protoplanetary disk in which they form. We used James Webb Space Telescope mid-infrared spectroscopy to investigate the chemical composition of the planet-forming disk around ISO-ChaI 147, a 0.11-solar-mass star. The inner disk has a carbon-rich chemistry; we identified emission from 13 carbon-bearing molecules, including ethane and benzene. The high column densities of hydrocarbons indicate that the observations probe deep into the disk. The high carbon-to-oxygen ratio indicates radial transport of material within the disk, which we predict would affect the bulk composition of any planets forming in the disk.

Water in the terrestrial planet-forming zone of the PDS 70 disk.

Terrestrial and sub-Neptune planets are expected to form in the inner (less than 10 AU) regions of protoplanetary disks1. Water plays a key role in their formation2-4, although it is yet unclear whether water molecules are formed in situ or transported from the outer disk5,6. So far Spitzer Space Telescope observations have only provided water luminosity upper limits for dust-depleted inner disks7, similar to PDS 70, the first system with direct confirmation of protoplanet presence8,9. Here we report JWST observations of PDS 70, a benchmark target to search for water in a disk hosting a large (approximately 54 AU) planet-carved gap separating an inner and outer disk10,11. Our findings show water in the inner disk of PDS 70. This implies that potential terrestrial planets forming therein have access to a water reservoir. The column densities of water vapour suggest in-situ formation via a reaction sequence involving O, H2 and/or OH, and survival through water self-shielding5. This is also supported by the presence of CO2 emission, another molecule sensitive to ultraviolet photodissociation. Dust shielding, and replenishment of both gas and small dust from the outer disk, may also play a role in sustaining the water reservoir12. Our observations also reveal a strong variability of the mid-infrared spectral energy distribution, pointing to a change of inner disk geometry.

The diverse chemistry of protoplanetary disks as revealed by JWST.

Early results from the James Webb Space Telescope-Mid-InfraRed Instrument (JWST-MIRI) guaranteed time programs on protostars (JOYS) and disks (MINDS) are presented. Thanks to the increased sensitivity, spectral and spatial resolution of the MIRI spectrometer, the chemical inventory of the planet-forming zones in disks can be investigated with unprecedented detail across stellar mass range and age. Here, data are presented for five disks, four around low-mass stars and one around a very young high-mass star. The mid-infrared spectra show some similarities but also significant diversity: some sources are rich in CO2, others in H2O or C2H2. In one disk around a very low-mass star, booming C2H2 emission provides evidence for a "soot" line at which carbon grains are eroded and sublimated, leading to a rich hydrocarbon chemistry in which even di-acetylene (C4H2) and benzene (C6H6) are detected. Together the data point to an active inner disk gas-phase chemistry that is closely linked to the physical structure (temperature, snowlines, presence of cavities and dust traps) of the entire disk and which may result in varying CO2/H2O abundances and high C/O ratios >1 in some cases. Ultimately, this diversity in disk chemistry will also be reflected in the diversity of the chemical composition of exoplanets.

Results of retroperitoneal laparoscopic radical nephrectomy.

PURPOSE: To analyze the retroperitoneal approach to laparoscopic radical nephrectomy in terms of feasibility, safety, morbidity, and cancer control. PATIENTS AND METHODS: We reviewed the records of 50 consecutive patients with renal cancer underwent radical nephrectomy via the retroperitoneal laparoscopic approach from 1995 through 1999. RESULTS: The mean operative time was 139 minutes (range 60-330 minutes) with a mean of 149.78-mL operative blood loss (0-1500 mL). The mean renal size was 100 mm (70-150 mm) with a mean tumor size of 38.6 mm (20-90 mm). The postoperative hospital was 6 days (2-13 days). Three open conversions were necessary: one for laparoscopically uncontrolled bleeding and two because obesity interfered with surgery. We noted two major complication and two minor complications. Two disease progression have been noted to date. One patient with a pT3 grade 2 renal-cell carcinoma had a local recurrence with liver metastasis 9 months after the procedure and died 19.7 months after radical nephrectomy. Another patient with a pT3aN+M+ cancer died 23.1 months after the procedure. CONCLUSION: Retroperitoneal laparoscopic nephrectomy for kidney cancer requires further assessment. It seems to have several advantages over open radical nephrectomy and to be effective and safe for small (<50-mm) renal tumors.

[Retrospective study of laparoscopic peritoneal radical nephrectomy]. / Etude rétrospective des néphrectomies élargies par voie laparoscopique rétropéritonéale.

OBJECTIVE: To analyse the results of laparoscopic radical nephrectomy in terms of feasibility, safety, morbidity and tumour control. MATERIAL AND METHODS: Between August 1993 and July 1998, 29 laparoscopic retroperitoneal radical nephrectomies were performed in 17 men and 12 women for renal tumours less than or equal to 90 mm in diameter. The working space was created by finger dissection without using a dilatation balloon. Four additional trocars were inserted under digital control. The renal pedicle was dissected first: the renal artery was clipped and the renal vein was sectioned by EndoGIA. After sectioning the ureter, the kidney was dissected with the perirenal fat and Gerota's fascia. The operative specimen was extracted in an impermeable endoscopy bag, without division, by enlarging the first trocar incision to 50 mm in order to avoid any parietal contact. RESULTS: The mean age of the patients was 61.3 years (range: 40 to 78 years). Radical nephrectomy was performed on 13 right kidneys and 16 left kidneys, with mean dimensions of 112.9 mm (range: 85 to 150 mm). The mean tumour diameter was 40.2 mm (range: 20 to 90 mm). The mean operating time was 145 min (range: 80 to 330 min) with a mean blood loss of 100 cc (range: 0 to 1000 cc). A mean daily dose of 2.8 g (range: 1 to 5 g) of parenteral paracetamol and a mean daily dose of 1.8 mg (range: 0 to 10 mg) of morphine hydrochloride were necessary postoperatively. The mean hospital stay was 4.8 days (range: 1 to 11 days). One intraoperative haemorrhage required open conversion and one colon injury was treated by temporary colostomy. One local recurrence with hepatic metastasis occurred 9 months after the operation in a patient operated for a Furhman grade II stage pT3 tumour with negative resection margins. CONCLUSION: Laparoscopic radical nephrectomy is currently under evaluation. This technique is feasible, and respects the principles of cancer surgery: primary control of renal vessels, en bloc extraction of the kidney with Gerota's fascia.

Retroperitoneal laparoscopic versus open radical nephrectomy.

PURPOSE: We analyze the retroperitoneal approach to laparoscopic radical nephrectomy in regard to feasibility, safety, morbidity and cancer control, and compare results and outcomes in patients who underwent retroperitoneal laparoscopic or open radical nephrectomy from 1995 to 1998. MATERIALS AND METHODS: The records of 58 consecutive patients with renal cancer who underwent radical nephrectomy from 1995 through 1998 were reviewed. Of the patients 29 underwent open radical nephrectomy (group 1) and 29 underwent retroperitoneal laparoscopic radical nephrectomy (group 2). Various parameters were compared and statistical analyses were performed. RESULTS: The 2 groups were similar in regard to age, gender and side of the tumor. Operative time was slightly shorter in group 1 (mean 121.4 versus 145 minutes in group 2, p = 0.047). Mean tumor size plus or minus standard deviation was larger in group 1 (5.71 +/- 2.01 versus 4.02 +/- 1.87 cm. in group 2). Group 2 patients had significantly less operative blood loss (mean 100.0 versus 284.5 ml. in group 1, p < 0.005) and used significantly less parenteral pain medication (p < 0.05). Postoperative hospital stay was significantly longer in group 1 (9.7 +/- 3.6 versus 4.8 +/- 2.0 days in group 2, p < 0.001), and the complication rate was higher (24 versus 8%, respectively). One group 1 patient died of renal cancer (pT2G2) after 14 months and local recurrence with hepatic metastasis occurred after 9 months in a group 2 patient with a pT3G2 tumor. CONCLUSIONS: Retroperitoneal laparoscopic nephrectomy for kidney cancer requires further assessment. It seems to have several advantages over open radical nephrectomy, and to be effective and safe for less than 50 cm. renal tumors but a risk of spillage cannot be ruled out for larger tumors.

Retroperitoneoscopic nephroureterectomy for renal pelvic tumors with a single iliac incision.

PURPOSE: Retroperitoneal laparoscopy, by providing direct access to the retroperitoneal cavity, is a useful approach to urological surgery. We applied this technique to nephroureterectomy in patients with tumors of the renal pelvis. MATERIALS AND METHODS: Between January 1995 and March 1997 we performed 4 retroperitoneal laparoscopic nephroureterectomies in patients with tumors of the renal pelvis. The patients were placed in the lateral decubitus position. Five trocars were used. Balloon dilation was not contributory. Radical nephrectomy was performed and the kidney was left in the retroperitoneal space. Via an iliac incision ureterectomy with a bladder cuff was performed and the specimen was removed (kidney and ureter) en bloc via this incision without opening the urinary tract. RESULTS: One right and 3 left nephroureterectomies were performed with an average operating time of 220 minutes (range 160 to 300). Average kidney size was 110 mm. (range 100 to 120). Average hospital stay was 5.7 days (range 5 to 7). Blood loss was minimal and postoperative analgesic requirements were moderate. Conversion to open surgery was never necessary. The morbidity rate was zero. The pathological stages were pT2 G2, pT3 G2, pT3G3 and pT3 G2-G3 N+. A local recurrence was observed in a patient with a pT3 G3 tumor. CONCLUSIONS: Nephroureterectomy can be performed by retroperitoneal laparoscopy. The perioperative morbidity and hospital stay are reduced. Further followup is required to evaluate long-term results in terms of cancer outcome.

Eight year improvement in pathological results after radical prostatectomy.

The purpose of this paper is to compare the pathological stage of prostate cancer specimens with preoperative characteristics according to the year of diagnosis. One hundred and seventy five patients underwent radical prostatectomy for localized disease between January 1989 and December 1996. In each year group, the mean preoperative PSA (Prostate Substance Antigen, Hybutech((R)) Assay Nl

[Improvement over time of oncological results after radical prostatectomy: what are the responsible factors?]. / Amélioration au cours du temps des résultats carcinologiques après prostatectomie radicale: quels en sont les facteurs responsables?

OBJECTIVES: The histological results after radical prostatectomy constitute one of the main prognostic factors. We studied the course of these results over time in order to assess their improvement and to identify the factors responsible. MATERIAL AND METHODS: 175 radical prostatectomies were performed between 1989 and 1996. The preoperative assessment for each patient comprised clinical examination, PSA assay, and histological examination of 6 ultrasound-guided transrectal biopsies. All radical prostatectomy specimens were analysed according to the Stanford technique by the same pathologist: the weight of the prostatectomy specimen, the Gleason score, existence of capsular effraction, seminal vesicle invasion, positive lymph node dissection and the presence of positive surgical margins were studied. The results were studied and compared year by year using Student's test and the Chi-square test. RESULTS: From 1989 to 1996, stages pT1-pT2 increased from 40 to 81.8%, while the positive resection margin rate decreased from 80 to 18.1%. No difference was observed over time for weight and Gleason score. Among the preoperative factors, no difference was observed for age of the patients, number of positive biopsies and Gleason score of these biopsies. Only the mean preoperative PSA level decreased from 52.2 to 12.2 ng/ml (t = 0.0001) and the number of stage T1c tumours increased from 13.3 to 59%. CONCLUSION: The preoperative PSA level is the main factor explaining improvement of the oncological results, especially as the tumours operated between 1988 and 1996 were identical in terms of aggressiveness (Gleason score). This improvement of the results reflects better patient selection, although this selection is performed case by case without exclusive factors.

[The value of prostatic biopsy in tumor mapping]. / Valeur des biopsies prostatiques dans la cartographie tumorale.

OBJECTIVES: Prostatic biopsies, a diagnostic tool, are also used as prognostic elements before radical prostatectomy. Their sites within the prostatic gland constitute one of these prognostic criteria. The authors compared the site of positive prostatic biopsies with that of the tumour after radical prostatectomy in order to study the value of this prognostic factor and the way in which it can be improved. MATERIAL AND METHODS: From 1988 to 1996, 166 localized prostatic tumours treated by radical prostatectomy were diagnosed by 6 systematized ultrasound-guided transrectal biopsies and 3 supplementary median biopsies performed from the base to the prostatic apex. The site of positive biopsies was compared to that of the tumour within the prostatic gland. RESULTS: Of the 996 sextant biopsies performed, 331 (33%) were positive, i.e. 1.99 biopsies per prostate. 92 (19%) median biopsies were positive. 331 positive sextant biopsies corresponded to a tumour within the prostate with a specificity of 81.5%, a sensitivity of 39.4%, a positive predictive value (PPV) of 83.3%, a negative predictive value (NPV) of 36.4% and an accuracy of 52%. For 3 median biopsies, the sensitivity was 70.3%, the specificity was 91.6%, the PPV was 61.9%, the NPV was 94%, and the accuracy was 82%. The weight of the prostate (prostates less than and greater than 45 g), influenced these results, as PPV decreased from 90.8% to 76.1% while NPV increased from 32.9% to 37.8%. CONCLUSION: Negative biopsies in a prostatic zone after 6 randomized biopsies do not exclude the presence of tumour in this zone and cannot be used as a prognostic element before radical prostatectomy for the therapeutic management. The presence of negative biopsies in a prostatic zone must be interpreted by taking the prostatic weight into account. 3 median biopsies are more accurate and less influenced by prostatic weight.

Laparoscopic adrenalectomy: the retroperitoneal approach.

PURPOSE: Retroperitoneal laparoscopy, by providing direct access to the retroperitoneal cavity, is an interesting approach to urological surgery. We report our initial experience with retroperitoneal laparoscopic adrenalectomy. MATERIALS AND METHODS: Between January 1995 and April 1997, 23 adrenalectomies were performed by retroperitoneal laparoscopy in 10 men and 12 women. The patients were placed in the lateral decubitus position and 5 trocars were used. The retroperitoneal working space was created by digital dissection and was completed by insufflation without balloon dissection. The surgical indications were Conn's adenoma in 12 cases, Cushing's adenoma in 4, bilateral adrenal hyperplasia (Cushing's disease) in 1 (treated in a single procedure), a nonfunctioning adenoma in 2, pheochromocytoma in 2 and adrenal metastasis in 1. RESULTS: We removed 7 right and 16 left adrenal glands in an average operating time of 97 minutes (range 45 to 160). Average tumor size was 26 mm. (range 10 to 40). Average hospital stay was 3.3 days (range 1 to 10). Blood loss was minimal. Postoperative analgesic requirements were moderate. Conversion to open surgery was not necessary. The morbidity rate was low, with 1 postoperative hematoma and 1 case of persistent fever (greater than 38.5C). CONCLUSIONS: Retroperitoneal adrenalectomy is a reliable and effective technique. At our institution retroperitoneal laparoscopy is now the standard adrenal surgery procedure for tumors less than 5 cm.

Biopsy-based diagnosis of prostate cancer in 1290 patients referred for prostate examination: results according to the PSA level, digital rectal examination and ultrasonography.

Authors present their retrospective study of 1290 patients referred for prostate evaluation. The risk of cancer was analysed according to PSA, rectal palpation and ultrasound examination. Among the 1290 patients, 54.8% had cancer. The risk of cancer was multiplied by 2.8 when the PSA was between the normal limit and 10 ng/ml, by 7.5 when it exceeded 10 ng/ml, by 4.0 when rectal palpation was abnormal and by 1.6 when a hypoechogenic zone was present. Although a hypoechogenic zone does not improve the detection of cancer compared to PSA and rectal palpation, an increased PSA level even lower than 10 ng/ml indicates biopsies.

[Retropubic and perineal approach: plea for perineal radical prostatectomy]. / Voies rétropubienne et périnéale: plaidoyer pour la prostatectomie radicale par voie périnéale.

OBJECTIVES: Two surgical approaches are proposed for radical prostatectomy: the retropubic route and the perineal route. We compared the surgical, oncological and functional aspects of these two approaches and present arguments suggesting that the perineal approach is the preferred approach for radical prostatectomy. MATERIAL AND METHODS: 55 retropubic radical prostatectomies were retrospectively compared to 55 perineal radical prostatectomies and performed between March 1992 to December 1995. The clinical TNM, preoperative PSA, results of 6 systematized intrarectal biopsies, operating time, intraoperative bleeding, number of patients transfused and number of packed cell units per patient transfused, medical and surgical complications, catheterization time and length of hospital stay, incidence of urethrovesical anastomosis leak and stenosis, analysis of the prostatectomy specimen, course of PSA, continence and erection were studied. RESULTS: Statistically significant differences were observed for the retropubic and perineal approaches, respectively: preoperative PSA (24 vs 15 ng/mL), intraoperative bleeding (2664 vs 1071 mL), number of patients transfused (91% vs 28%), number of packed cell units per patient transfused (3.9 vs 2.7), medical and surgical complications (56.9 vs 29.1%), anastomotic leak (24.1 vs 7.2%), anastomotic stenosis (31.5 vs 1.8%), duration of catheterization (18 vs 13 days) and length of hospital stay (14 vs 8 days). At 2 years, PSA remained less than 0.5 ng/mL in both groups. CONCLUSION: Even taking the learning period into account, the perineal approach provides the same results as the retropubic approach in terms of functional and oncological parameters, with a simpler postoperative course for patient.

Prostate Biopsy in the staging of prostate cancer.

The use of prostate biopsies was developed in parallel with progress in our knowledge of prostate cancer and the use of prostate-specific antigen (PSA). Prostate biopsies were initially indicated for the diagnosis of cancer, by the perineal approach under general anesthesia. Nowadays prostate biopsies are not only for diagnostic purposes but also to determine the prognosis, particularly before radical prostatectomy. They are performed in patients with elevated PSA levels, by the endorectal approach, sometimes under local anesthesia. The gold standard is the sextant biopsy technique described by Hodge, which is best to diagnose prostate cancer, particularly in case of T1c disease (patients with serum PSA elevation). Patients with a strong suspicion of prostate cancer from a negative series of biopsies can undergo a second series with transition zone biopsy or lateral biopsy. Karakiewicz et al and Uzzo et al proposed that the number of prostate biopsies should depend on prostate volume to improve the positivity rate. After the diagnosis of prostate cancer, initial therapy will depend on several prognostic factors. In the case of radical prostatectomy, the results of sextant biopsy provide a wealth of information. The aim of this report is to present the information given by prostate biopsy in the staging of prostate cancer.

[Prognostic value of a positive single ultrasound-guided prostatic biopsy regarding tumor volume and intracapsular nature of prostatic adenocarcinoma]. / Valeur pronostique d'une unique biopsie prostatique échoguidée positive sur le volume tumoral et le caractère intracapsulaire de l'adénocarcinome prostatique.

OBJECTIVE: Study of the value of a single positive prostatic biopsy in the staging of prostatic carcinoma and the significance of the tumour volume. METHOD: The clinical, laboratory and pathological parameters were studied in 27 prostatectomized patients with a single positive prostatic biopsy. RESULTS: The length of tumour invasion on the biopsy was 2.6 mm (evaluation on 25 biopsies). Six patients (23%) had an extracapsular tumour and 21 (78%) had a significant tumour volume. Among the 16 patients with a length of tumour invasion < or = 3 mm, 13 (81%) had a significant tumour volume. 25% of patients with less than 3 mm of invasion on the biopsy and a Gleason score < or = 6 and 12% of patients with less than 3 mm of invasion and a PSA < or = 10 ng/ml had a non-significant tumour volume. CONCLUSION: The presence of a single positive prostatic biopsy is not sufficient to determine the pathological stage of a prostatic carcinoma. In this retrospective study, the majority of patients with a single positive biopsy had a significant tumour volume > 0.5 cc. No preoperative predictive factor of tumour volume was demonstrated.

Retroperitoneoscopy: a laparoscopic approach for adrenal and renal surgery.

OBJECTIVES: Retroperitoneoscopy has gained acceptance for urologic surgery. We assessed the safety and efficacy of this procedure for renal and adrenal surgery. METHODS: Since December 1994, 20 patients (18 to 75 years old) have undergone laparoscopic adrenalectomy and nephrectomy, including simple nephrectomy in 8, partial nephrectomy in 1, radical nephrectomy in 2, tumorectomy with cyst excision in 1, and adrenalectomy in 8. The retroperitoneal space was created by blunt dissection with the index finger, completed by insufflation, without balloon dissection. RESULTS: Average kidney size was 65 m (range 50 to 108), and average adrenal tumor size was 31 mm (range 20 to 40). The average operating time was 127 minutes (range 60 to 180) for nephrectomy and 84 minutes (range 45 to 140) for adrenalectomy. The average hospital stay was 3 days (range 1 to 7) for nephrectomy and 2.4 days (range 1 to 4) for adrenalectomy. Average blood loss was 65 mL for both nephrectomy and adrenalectomy. Conversion from the laparoscopic procedure to open surgery was never required. Peritoneal effraction and ureteral injury occurred in only 4 patients and 1 patient, respectively. CONCLUSIONS: The laparoscopic retroperitoneal approach is safe and effective for simple renal nephrectomy and for excision of small adrenal tumors. Perioperative morbidity and hospital stay are reduced.