Ancient marine sediment DNA reveals diatom transition in Antarctica.

Antarctica is one of the most vulnerable regions to climate change on Earth and studying the past and present responses of this polar marine ecosystem to environmental change is a matter of urgency. Sedimentary ancient DNA (sedaDNA) analysis can provide such insights into past ecosystem-wide changes. Here we present authenticated (through extensive contamination control and sedaDNA damage analysis) metagenomic marine eukaryote sedaDNA from the Scotia Sea region acquired during IODP Expedition 382. We also provide a marine eukaryote sedaDNA record of ~1 Mio. years and diatom and chlorophyte sedaDNA dating back to ~540 ka (using taxonomic marker genes SSU, LSU, psbO). We find evidence of warm phases being associated with high relative diatom abundance, and a marked transition from diatoms comprising <10% of all eukaryotes prior to ~14.5 ka, to ~50% after this time, i.e., following Meltwater Pulse 1A, alongside a composition change from sea-ice to open-ocean species. Our study demonstrates that sedaDNA tools can be expanded to hundreds of thousands of years, opening the pathway to the study of ecosystem-wide marine shifts and paleo-productivity phases throughout multiple glacial-interglacial cycles.

Episodes of Early Pleistocene West Antarctic Ice Sheet Retreat Recorded by Iceberg Alley Sediments.

Ice loss in the Southern Hemisphere has been greatest over the past 30 years in West Antarctica. The high sensitivity of this region to climate change has motivated geologists to examine marine sedimentary records for evidence of past episodes of West Antarctic Ice Sheet (WAIS) instability. Sediments accumulating in the Scotia Sea are useful to examine for this purpose because they receive iceberg-rafted debris (IBRD) sourced from the Pacific- and Atlantic-facing sectors of West Antarctica. Here we report on the sedimentology and provenance of the oldest of three cm-scale coarse-grained layers recovered from this sea at International Ocean Discovery Program Site U1538. These layers are preserved in opal-rich sediments deposited ∼1.2 Ma during a relatively warm regional climate. Our microCT-based analysis of the layer's in-situ fabric confirms its ice-rafted origin. We further infer that it is the product of an intense but short-lived episode of IBRD deposition. Based on the petrography of its sand fraction and the Phanerozoic 40Ar/39Ar ages of hornblende and mica it contains, we conclude that the IBRD it contains was likely sourced from the Weddell Sea and/or Amundsen Sea embayment(s) of West Antarctica. We attribute the high concentrations of IBRD in these layers to "dirty" icebergs calved from the WAIS following its retreat inland from its modern grounding line. These layers also sit at the top of a ∼366-m thick Pliocene and early Pleistocene sequence that is much more dropstone-rich than its overlying sediments. We speculate this fact may reflect that WAIS mass-balance was highly dynamic during the ∼41-kyr (inter)glacial world.

Antiphased dust deposition and productivity in the Antarctic Zone over 1.5 million years.

The Southern Ocean paleoceanography provides key insights into how iron fertilization and oceanic productivity developed through Pleistocene ice-ages and their role in influencing the carbon cycle. We report a high-resolution record of dust deposition and ocean productivity for the Antarctic Zone, close to the main dust source, Patagonia. Our deep-ocean records cover the last 1.5 Ma, thus doubling that from Antarctic ice-cores. We find a 5 to 15-fold increase in dust deposition during glacials and a 2 to 5-fold increase in biogenic silica deposition, reflecting higher ocean productivity during interglacials. This antiphasing persisted throughout the last 25 glacial cycles. Dust deposition became more pronounced across the Mid-Pleistocene Transition (MPT) in the Southern Hemisphere, with an abrupt shift suggesting more severe glaciations since ~0.9 Ma. Productivity was intermediate pre-MPT, lowest during the MPT and highest since 0.4 Ma. Generally, glacials experienced extended sea-ice cover, reduced bottom-water export and Weddell Gyre dynamics, which helped lower atmospheric CO2 levels.

Laparoscopic cholecystectomy in patients over 70 years of age: review of 176 cases.

INTRODUCTION: We assessed the results of laparoscopic cholecystectomy in 176 patients over the age of 70 years. PATIENTS AND METHODS: The study included all patients older than 70 years of age who underwent laparoscopic surgery cholelithiasis during the previous ten years. Variables studied included age, sex, type of operation (programmed/emergency), comorbidity, anesthetic risk, intraoperative cholangiography, conversion to open surgery, number of trocars, reoperation, residual choledocholithiasis, postoperative hospital stay, morbidity and mortality. RESULTS: The study included 176 patients (23.29% men and 76.71% women). The mean age was 74.86 years. The mean hospital stay was 1.27 days, with 16.98% morbidity and 0.56% mortality. CONCLUSIONS: Laparoscopic cholecystectomy is a safe procedure in older patients. It results in faster recovery, a shorter postoperative stay and lower rates of morbidity and mortality than open bile duct surgery.

Do we really know the symptoms of inguinal hernia?

PURPOSE: Although there is a high incidence of inguinal hernia in developed countries, few studies have been conducted to describe the symptoms, and these few only address the local symptoms, not those presenting at other levels. The aim of the present study is to conduct a detailed review of the symptoms, both inguinal and otherwise, of patients with inguinal hernia. METHODS: A case-control study was designed to compare the symptoms presented by 231 patients diagnosed with inguinal hernia with those of a second group of 231 randomly-selected subjects. In the hernia group, the symptoms were also evaluated according to the location of the hernia (right, left, bilateral). RESULTS: Significant differences (more symptomatology in patients with hernia) were found for the following items: groin pain, genital pain, urinary symptoms, abdominal pain, increased peristalsis and tenesmus. On the contrary, the control patients presented greater symptomatology with respect to back pain and diaphragm pain. CONCLUSIONS: Patients with inguinal hernia present a wide variety of symptoms, and these are not restricted to the inguinal area. It is important to be aware of this fact to convey accurate information to the patient, especially with regard to postoperative expectations.

Study of factors related to quality of life in patients with locally advanced rectal cancer.

OBJECTIVES: Given the increasing concern about the physical, psychological, and social welfare of patients surgically treated for rectal cancer, we designed a study of the factors influencing quality of life in these patients. EXPERIMENTAL DESIGN: We prospectively analyzed factors related to quality of life in a cohort of patients using the Nottingham Health Profile and the EORTC questionnaire (QLQ-CR 38). PATIENTS: A total of 116 patients with locally advanced rectal cancer surgically treated in our hospital from 1994 to 1999. RESULTS: Quality of life scores for the various factors studied showed that quality of life was worse in women, in patients with tumors in the middle third of the rectum, and in patients undergoing low anterior resection. CONCLUSIONS: Factors influencing quality of life in patients surgically treated for locally advanced rectal cancer included sex, tumor site, and surgical technique. Since only this latter factor is modifiable, we suggest that the surgical technique be individualized in persons with mid-lower and lower-third tumors of the rectum, bearing in mind that quality of life in amputated patients is, in many respects, better than that of patients with preserved sphincters.

[Pancreatic cystic metastasis from pulmonary carcinoma. Report of a case]. / Metastasi cistica pancreatica da carcinoma polmonare. Presentazione di un caso.

We report the case of a patients with a metachronous cystic pancreatic metastasis from an undifferentiated large cell lung carcinoma two years after the primary tumor had been surgically removed. Clinically, he presented with epigastric pain, fever, weakness and anorexia. The patient was operated and a palliative cystogastrostomy was performed after an intraoperative biopsy had been informed as positive for carcinoma. Six months later the patient died. Pancreatic metastases from lung carcinoma are found in approximately 7-9% of patients deceased of this neoplasm. Clinical and radiological findings simulate primary pancreatic tumors, being epigastric pain, jaundice and upper digestive bleeding the most frequent symptoms. They represent stages of advanced systemic disseminated tumoral disease, and because of this reason total or partial surgical curative resections will only be performed in a few cases of patients with isolated metastasis, criteria of resectability and without evidence of extended disease to other organs or systems. In the most of the cases, the treatment will only be palliative, even medical or surgical.

Resorbable synthetic mesh supported with omentum flap in the treatment of giant hiatal hernia.

Covering a large hiatal hernia with a mesh has become a basic procedure in the last few years. However, mesh implants are associated with high complication rates (esophageal erosion, perforation, fistula, etc.). We propose using a synthetic resorbable mesh supported with an omental flap as a possible solution to this problem. A 54-year-old female patient with a large hiatal defect (9 cm) was laparoscopically implanted with a synthetic resorbable mesh supported with an omental flap. The surgical procedure was successful and the patient was discharged on postoperative day 2. On a follow-up examination 6 months after surgery, she remained free of relapse or complication signs. Supporting an implanted resorbable mesh with an omental flap may be a solution to the problems posed by large esophageal hiatus defects. However, more studies based on larger patient samples and longer follow-up periods are necessary.