The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation

Haumea-one of the four known trans-Neptunian dwarf planets-is a very elongated and rapidly rotating body. In contrast to other dwarf planets, its size, shape, albedo and density are not well constrained. The Centaur Chariklo was the first body other than a giant planet known to have a ring system, and the Centaur Chiron was later found to possess something similar to Chariklo's rings. Here we report observations from multiple Earth-based observatories of Haumea passing in front of a distant star (a multi-chord stellar occultation). Secondary events observed around the main body of Haumea are consistent with the presence of a ring with an opacity of 0.5, width of 70 kilometres and radius of about 2,287 kilometres. The ring is coplanar with both Haumea's equator and the orbit of its satellite Hi'iaka. The radius of the ring places it close to the 3:1 mean-motion resonance with Haumea's spin period-that is, Haumea rotates three times on its axis in the time that a ring particle completes one revolution. The occultation by the main body provides an instantaneous elliptical projected shape with axes of about 1,704 kilometres and 1,138 kilometres. Combined with rotational light curves, the occultation constrains the three-dimensional orientation of Haumea and its triaxial shape, which is inconsistent with a homogeneous body in hydrostatic equilibrium. Haumea's largest axis is at least 2,322 kilometres, larger than previously thought, implying an upper limit for its density of 1,885 kilograms per cubic metre and a geometric albedo of 0.51, both smaller than previous estimates. In addition, this estimate of the density of Haumea is closer to that of Pluto than are previous estimates, in line with expectations. No global nitrogen- or methane-dominated atmosphere was detected.

Bone fracture in breast cancer patients with isolated bone metastasis

AIM

To analyse the incidence of bone fracture of breast cancer patients with isolated bone metastasis and its effect on survival. We tried to find an answer to the question of "Can the development of bone fracture be predicted?"

METHODS

Between 1993-2006, 139 breast cancer patients with isolated bone metastasis were examined. Patients were divided into two groups depending on the development of pathologic bone fracture.

RESULTS

Fractures were developed in 41 patients (29.5%)within 41 months of follow-up. The locations of pathologic bone fracture were vertebral fracture in 26 patients (63.4%),femur fracture in 11 patients (26.8%), and hip fracture in four patients (9.8%). Fracture rates in hormone sensitive and resistant patients were 31.2% and 14.3%, respectively. The fracture rates in 13 triple negative and non triple negative patients were 7.7% and 31.4%, respectively (p=0.07). High CA 15-3 levels at the time of metastasis in patients with and without fractures were 68.4% and 61.1%, respectively. The risk for fracture was also high in Her2-neu positive patients (38.7% vs. 26.5%). While the incidence of fracture with the presence of one factor mentioned above was 22.2%, it was increased to 36.1% in the presence of two or three factors(p=0.13). Median survivals of the patients with and without fractures were 48 and 39 months, respectively (p= 0.65).

CONCLUSION

Hormone sensitivity, high CA 15-3 levels and positive Her2-neu status are slight risk factors for bone fractures. Survival was not different in patients with or without bone fractures.

In which cases surgical gastrostomy and jejunostomy techniques are inevitable?

PURPOSE

This study investigated the surgical gastrostomy and jejunostomy procedures in cancer patients who needed nutritional support and endoscopy was unattainable.

METHODS

Operation time and procedure, anesthesia and tube types, procedure-specific and surgical complications, and tube replacement at the follow up period were retrospectively analyzed.

RESULTS

109 patients (44 female, 65 male, mean age 50.9 years, range 14-87) were subjected to surgical gastrostomy/ jejunostomy. Ninety-three (85.4%) patients had head-neck and gastrointestinal cancers. In 94 (86.2%) patients endoscopy was impossible due to obstruction of the esophagus and stomach. Gastrostomy/jejunostomy was combined with other surgical procedures in 12 (11 %) patients. Procedure- related complications occurred in 22 (20.7%) patients. Early 30-day mortality occurred in 12 (11 %) cases. The median follow up period was 3.6 months (range 0-18).

CONCLUSION

Obstructing cancer, obesity or previous laparotomy make the use of endoscopic techniques impossible. For these patients, surgical gastrostomy/jejunostomy is safe with acceptable complication rates and improves the treatment outcomes with nutritional support.

Characteristics and risk factors for colorectal cancer recurrence

PURPOSE

To evaluate the characteristics of recurrence and examine the clinicopathological factors related to disease- free (DFS) and overall survival (OS) of patients with colorectal cancer (CRC) recurrence.

METHODS

One hundred and sixteen CRC patients with stage II and III disease that had been resected curatively in our clinic between 1999 and 2006 were retrospectively evaluated. The parameters evaluated were gender, age, preoperative CEA levels, tumor localisation, duration of surgery, the units of perioperative blood transfusion, tumor differentiation, TNM stages and adjuvant therapies. The presence of preoperative intestinal obstruction, radical abdominopelvic lymph node (RAPL) dissection and lymphatic, vascular and perineural invasion were also evaluated.

RESULTS

With 36.6+/-2 months follow-up, 49 (42%) patients developed local recurrence and/or distant metastases. Twenty-three (19.8%) patients presented with isolated local recurrence. Thirteen of 49 patients with local recurrence were successfully operated with R0 curative resection. The OS survival rates for those with curatively and palliatively resected recurrences were 29 and 19 months, respectively. In multivariate analysis, the factors related to DFS were tumor localisation and differentiation, neurovascular invasion, blood transfusion and RAPL dissection. Among these factors, only RAPL dissection was not statistically significant for OS.

CONCLUSION

The factors increasing local recurrence rates of CRC should be clearly described. Local and systemic treatment modalities, like preoperative chemoradiotherapy should be planned for patients carrying these risk factors.

Locally advanced breast carcinoma treated with neoadjuvant chemotherapy: are the changes in serum levels of YKL-40, MMP-2 and MMP-9 correlated with tumor response?

Serum levels of YKL-40, MMP-2 and MMP-9 in 27 patients with locally advanced breast carcinoma received neoadjuvant chemotherapy were measured. All patients underwent neoadjuvant chemotherapy named as FAC protocol (5-Fluorouracil, Doxorubicin and Cyclophosphamide) with 21 days interval. There was 26,7% decrease in mean serum YKL-40 levels (from 146,4 microg/ml to 107,3 microg/ml) in clinically responsive group. This level was almost unchanged in non-responsive group (P>0, 05). There was 42, 1% decrease in mean serum YKL-40 levels (from 173,1 microg/ml to 98, 8 microg/ml) in pathologically responsive group. This decrease was more dramatic in patients with complete pathological response (70, 2%). However, this level was slightly increased in non-responsive group. Changes in serum levels of MMP-2 and MMP-9 were not found to be associated with tumor response. Serum measurement of YKL-40 can be a helpful tool to predict pathological tumor response in breast cancer patients with neoadjuvant chemotherapy but not MMP-2 and MMP-9.