813 research outputs found
Is Late Recurrence after Radical Resection for Ampullary Carcinoma A Problem?
Of 36 patients with carcinoma of the ampulla of Vater who underwent surgery between
1971 and 1990, 31 had a radical operation. There was one operative death. The overall
5- and 10-year survival rates were 56 and 37 per cent respectively. Survival was
significantly influenced by tumour stage (p=0.0002), lymph node sthtus (p=0.006) and
the degree of differentiation of the lesion (P=0.01). Three patients developed local
recurrence after local excision of the tumour. Local or hepatic recurrence was common,
even 5 years after pancreatoduodenectomy (four of 18 patients who suffered relapse).
Radical resection can be curative in selected patients with ampullary carcinoma but late
recurrence suggests the need for careful lifelong follow-up
Resection of hilar cholangiocarcinoma
Objective: Morbidity and mortality involved in the resection of hilar cholangiocarcinoma were reviewed retrospectively. The clinicopathologic and laboratory parameters that might influence the patient's survival also were re-evaluated. Summary Background Data: Although much progress has been made in the diagnosis and management of hilar cholangiocarcinoma, long-term outlook for most patients remains poor. Surgical resection is usually prohibited because of its local invasiveness, and most patients can only be managed by palliative drainage. Recently, many surgeons have adopted a more aggressive resection with varying degrees of success. Several prognostic factors in bile duct carcinoma have been proposed; however, no reports have specifically focused on resected hilar cholangiocarcinoma and its prognostic survival factors using multivariate analysis. Methods: The clinical records and pathologic slides of 49 cases with resected hilar cholangiocarcinoma were reviewed retrospectively. Twenty clinical and laboratory parameters were evaluated for their correlation with postoperative morbidity and mortality, whereas 31 variables were evaluated for their significance with postoperative survival. Variables showing statistical significance in the first univariate analysis were included in the following multivariate analysis using stepwise logistic regression test for factors affecting morbidity and mortality and Cox stepwise proportional hazard model for factors influencing survival. Results: There were 5 in-hospital deaths, and the cumulative 5-year survival rate in 44 patients who survived was 14.9%, with a median survival of 14.0 months. Multivariate analysis disclosed that coexistent hepatolithiasis and lower serum asparate aminotransferase levels (90 U/L) had a significant low incidence of postoperative morbidity, whereas a serum albumin of less than 3 g/dL was the only significant factor affecting mortality. Regarding survival, univariate analysis identified eight significant factors: 1) total bilirubin 10 mg/dL, 2) curative resection, 3) histologic type, 4) perineural invasion, 5) liver invasion, 6) depth of cancer invasion, 7) positive proximal resected margin, and 8) positive surgical margin. However, multivariate analysis disclosed total bilirubin ≥ 10 mg/dL, curative resection, and histologic type as the three most significant independent variables. Conclusions: Surgical resection provides the best survival for bilar cholangiocarcinoma. An adequate nutritional support to increase serum albumin over 3g/dL is the most important factor to decrease postoperative mortality. Moreover, preoperative biliary drainage to decrease jaundice and a curative resection with adequate surgical margin are recommended if longer survival is anticipated. Patients with well differentiated adenocarcinoma seem to survive longer compared to those with moderately or poorly differentiated tumors
Pathogenesis of Cholesterol Gallstones
Cholesterol gallstone disease is extremely common. Three major stages are recognized for stone
formation, namely bile that becomes supersaturated with cholesterol, cholesterol nucleation leading to
crystal formation and finally retention of the crystals in the gallbladder resulting in stone formation.
Supersaturation is common but nucleation into crystals probably requires protein nucleating factors.
Impaired motility of the gallbladder causes crystal retention and is probably very important in stone
formation
Hierarchical Equations of Motion Approach to Quantum Thermodynamics
We present a theoretical framework to investigate quantum thermodynamic
processes under non-Markovian system-bath interactions on the basis of the
hierarchical equations of motion (HEOM) approach, which is convenient to carry
out numerically "exact" calculations. This formalism is valuable because it can
be used to treat not only strong system-bath coupling but also system-bath
correlation or entanglement, which will be essential to characterize the heat
transport between the system and quantum heat baths. Using this formalism, we
demonstrated an importance of the thermodynamic effect from the tri-partite
correlations (TPC) for a two-level heat transfer model and a three-level
autonomous heat engine model under the conditions that the conventional quantum
master equation approaches are failed. Our numerical calculations show that TPC
contributions, which distinguish the heat current from the energy current, have
to be take into account to satisfy the thermodynamic laws.Comment: 9 pages, 4 figures. As a chapter of: F. Binder, L. A. Correa, C.
Gogolin, J. Anders, and G. Adesso (eds.), "Thermodynamics in the quantum
regime - Recent Progress and Outlook", (Springer International Publishing
The second law and beyond in microscopic quantum setups
The Clausius inequality (CI) is one of the most versatile forms of the second
law. Although it was originally conceived for macroscopic steam engines, it is
also applicable to quantum single particle machines. Moreover, the CI is the
main connecting thread between classical microscopic thermodynamics and
nanoscopic quantum thermodynamics. In this chapter, we study three different
approaches for obtaining the CI. Each approach shows different aspects of the
CI. The goals of this chapter are: (i) To show the exact assumptions made in
various derivations of the CI. (ii) To elucidate the structure of the second
law and its origin. (iii) To discuss the possibilities each approach offers for
finding additional second-law like inequalities. (iv) To pose challenges
related to the second law in nanoscopic setups. In particular, we introduce and
briefly discuss the notions of exotic heat machines (X machines), and "lazy
demons".Comment: As a chapter of: F. Binder, L. A. Correa, C. Gogolin, J. Anders, and
G. Adesso (eds.), "Thermodynamics in the quantum regime - Recent Progress and
Outlook", (Springer International Publishing). v1 does not include references
to other book chapter
Jaundice: an important, poorly recognized risk factor for diminished survival in patients with adenocarcinoma of the head of the pancreas
AbstractObjectivesJaundice impairs cellular immunity, an important defence against the dissemination of cancer. Jaundice is a common mode of presentation in pancreatic head adenocarcinoma. The purpose of this study was to determine whether there is an association between preoperative jaundice and survival in patients who have undergone resection of such tumours.MethodsThirty possible survival risk factors were evaluated in a database of over 400 resected patients. Univariate analysis was used to determine odds ratio for death. All factors for which a P‐value of <0.30 was obtained were entered into a multivariate analysis using the Cox model with backward selection.ResultsPreoperative jaundice, age, positive node status, poor differentiation and lymphatic invasion were significant indicators of poor outcome in multivariate analysis. Absence of jaundice was a highly favourable prognostic factor. Interaction emerged between jaundice and nodal status. The benefit conferred by the absence of jaundice was restricted to patients in whom negative node status was present. Five‐year overall survival in this group was 66%. Jaundiced patients who underwent preoperative stenting had a survival advantage.ConclusionsPreoperative jaundice is a negative risk factor in adenocarcinoma of the pancreas. Additional studies are required to determine the exact mechanism for this effect
Clinical classification of symptomatic heterotopic pancreas of the stomach and duodenum: A case series and systematic literature review
BACKGROUND: Heterotopic pancreas (HP) is an aberrant anatomic malformation that occurs most commonly in the upper gastrointestinal tract. While the majority of heterotopic pancreatic lesions are asymptomatic, many manifest severe clinical symptoms which require surgical or endoscopic intervention. Understanding of the clinical manifestations and symptoms of HP is limited due to the lack of large volume studies in the literature. The purpose of this study is to review symptomatic cases at a single center and compare these to a systematic review of the literature in order to characterize common clinical manifestations and treatment of this disease. AIM: To classify the common clinical manifestations of heterotopic pancreas. METHODS: A retrospective review was conducted of pathologic samples containing heterotopic pancreas from 2000-2018. Review was limited to HP of the upper gastrointestinal tract due to the frequency of presentation in this location. Symptomatic patients were identified from review of the medical records and clinical symptoms were tabulated. These were compared to a systematic review of the literature utilizing PubMed and Embase searches for papers pertaining to heterotopic pancreas. Publications describing symptomatic presentation of HP were selected for review. Information including demographics, symptoms, presentation and treatment were compiled and analyzed. RESULTS: Twenty-nine patient were identified with HP at a single center, with six of these identified has having clinical symptoms. Clinical manifestations included, gastrointestinal bleeding, gastric ulceration with/without perforation, pancreatitis, and gastric outlet obstruction. Systemic review of the literature yielded 232 publications detailing symptomatic cases with only 20 studies describing ten or more patients. Single and multi-patient studies were combined to form a cohort of 934 symptomatic patients. The majority of patients presented with abdominal pain (67%) combined with one of the following clinical categories: (1) Dyspepsia, (n = 445, 48%); (2) Pancreatitis (n = 260, 28%); (3) Gastrointestinal bleeding (n = 80, 9%); and (4) Gastric outlet obstruction (n = 80, 9%). The majority of cases (n = 832, 90%) underwent surgical or endoscopic resection with 85% reporting resolution or improvement in their symptoms. CONCLUSION: Heterotopic pancreas can cause significant clinical symptoms in the upper gastrointestinal tract. Better understanding and classification of this disease may result in more accurate identification and treatment of this malformation
The reaction coordinate mapping in quantum thermodynamics
We present an overview of the reaction coordinate approach to handling strong
system-reservoir interactions in quantum thermodynamics. This technique is
based on incorporating a collective degree of freedom of the reservoir (the
reaction coordinate) into an enlarged system Hamiltonian (the supersystem),
which is then treated explicitly. The remaining residual reservoir degrees of
freedom are traced out in the usual perturbative manner. The resulting
description accurately accounts for strong system-reservoir coupling and/or
non-Markovian effects over a wide range of parameters, including regimes in
which there is a substantial generation of system-reservoir correlations. We
discuss applications to both discrete stroke and continuously operating heat
engines, as well as perspectives for additional developments. In particular, we
find narrow regimes where strong coupling is not detrimental to the performance
of continuously operating heat engines.Comment: 17 pages, 2 tables, 7 figures. As a chapter of: F. Binder, L. A.
Correa, C. Gogolin, J. Anders, and G. Adesso (eds.), "Thermodynamics in the
quantum regime - Recent Progress and Outlook", (Springer International
Publishing
Quantum Fluctuation Theorems
Recent advances in experimental techniques allow one to measure and control
systems at the level of single molecules and atoms. Here gaining information
about fluctuating thermodynamic quantities is crucial for understanding
nonequilibrium thermodynamic behavior of small systems. To achieve this aim,
stochastic thermodynamics offers a theoretical framework, and nonequilibrium
equalities such as Jarzynski equality and fluctuation theorems provide key
information about the fluctuating thermodynamic quantities. We review the
recent progress in quantum fluctuation theorems, including the studies of
Maxwell's demon which plays a crucial role in connecting thermodynamics with
information.Comment: As a chapter of: F. Binder, L. A. Correa, C. Gogolin, J. Anders, and
G. Adesso (eds.), "Thermodynamics in the quantum regime - Fundamental Aspects
and New Directions", (Springer International Publishing, 2018
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