In vitro measurements of optical properties of porcine brain using a novel compact device

Knowledge of the optical properties of tissues can be applied in numerous medical and scientific fields, including cancer diagnostics and therapy. There are many different ways of determining the optical properties of turbid media. The paper describes measurements of the optical properties of porcine brain tissue using novel instrumentation for simultaneous absorption and scattering characterisation of small turbid samples. Integrating sphere measurements are widely used as a reference method for determination of the optical properties of relatively thin turbid samples. However, this technique is associated with bulky equipment, complicated measuring techniques, interference compensation techniques and inconvenient sample handling. It is believed that the sphere for some applications can be replaced by a new, compact device, called the combined angular and spatially resolved head sensor, to measure the optical properties of thin turbid samples. The results compare very well with data obtained with an integrating sphere for well-defined samples. The instrument was shown to be accurate to within 12% for microa and 1% for micro's in measurements of intralipid-ink samples. The corresponding variations of data were 17% and 2%, respectively. The reduced scattering coefficient for porcine white matter was measured to be 100 cm(-1) at 633 nm, and the value for coagulated brain tissue was 65 cm(-1). The corresponding absorption coefficients were 2 and 3 cm(-1), respectively.

Quantitative data analysis for exploring outcomes in cardiac surgery

The article focuses on possibilities of statistical knowledge exploration to predict outcomes of surgical treatments. The outcomes were defined in relation to the measured peri- and intraoperative data, as well as follow-up patient questionnaire. Clinical consequences are expected in terms of a smaller data set with a better ability to predict the surgery outcomes and a better cost performance. The important questions that could discriminate quality of life (QoL) were: Relief from surgery?, Has cardiac surgery effected earlier symptoms? Work capacity? Consultations after the surgery? The performed data analysis proved to be efficient in the complex data set that was collected. Pain relief was identified to be significant, while relations between measured blood laboratory profile and later QoL were weak.

Knowledge representation forms for data mining methodologies as applied in thoracic surgery

Typical ways of disseminating and using results of clinical research are scientific journals and reports. Presentation forms are condensed and comprehensible mainly to the experts following the specific topics. A vast amount of information remains unutilized due to the complex form of presenting the knowledge. Subject of this research is to explore possibilities of representation and also visualization of the results obtained using data mining methodologies. The intention is to formulate more than scientific ways to communicate facts that are of interest for the clinicians, medical students and even patients. Internet technologies as already widely established media support knowledge representation forms such as hypertext documents and structured knowledge components. The "Assist Me" decision support system for surgical treatment of cardiac patients integrates several forms of data mining and representation methodologies. We are showing a feasibility study in which scientific outcomes were forwarded to a broad group of potential users.

Intestinal mucosal injury during porcine faecal peritonitis

OBJECTIVE

To assess the incidence of intestinal mucosal injury during faecal peritonitis in pigs, the relation of such lesions to haemodynamic variables, intramucosal pH (pHi), and endothelial adherence of polymorphonuclear leucocytes (PMNs).

DESIGN

Experimental laboratory study.

SETTING

University department of surgery, Sweden.

SUBJECTS

57 Juvenile pigs.

INTERVENTIONS

Pigs had faecal peritonitis induced (n = 39) or a sham procedure (n = 18). In addition, 15 animals were pretreated with the monoclonal CD18 receptor antibody IB4 before induction of peritonitis with the aim of preventing tissue accumulation of PMNs.

MAIN OUTCOME MEASURES

Development of mucosal lesions and correlation with haemodynamic variables.

RESULTS

17/18 (94%) of control animals had normal mucosa. The incidence of mucosal lesions in animals with faecal peritonitis was 56%. Animals with severe mucosal injury (grade 4-5) had significantly lower mean arterial pressure, cardiac index, and pHi during the last hour of the experiment compared with animals without mucosal lesions. Pretreatment with IB4 did not prevent the development of intestinal mucosal injuries. Intramucosal pH decreased during sepsis and was not affected by IB4.

CONCLUSIONS

Severe intestinal mucosal injury is associated with arterial hypotension, low cardiac index, and low pH. Neither the mucosal injury nor the reduction in pHi seen during porcine faecal peritonitis seemed to be leucocyte-related phenomena.

Intraoperative colonic lavage and primary anastomosis--an alternative to Hartmann procedure in emergency surgery of the left colon

OBJECTIVE

To assess whether intraoperative lavage and primary resection with anastomosis is a safe alternative to a Hartmann procedure in emergency surgery of the left colon.

DESIGN

Retrospective study.

SETTING

University hospital.

MATERIAL

101 consecutive patients (39 emergency and 62 elective) who underwent a left-sided colonic resection during a 3-year-period.

INTERVENTIONS

17 of the emergency procedures comprised an intraoperative lavage followed by resection and primary anastomosis without faecal diversion; 17 were Hartmann procedures and 5 patients had primary resection without lavage.

MAIN OUTCOME MEASURES

Postoperative mortality, morbidity and duration of hospital stay in these two groups compared with these after a contemporary series of elective resections.

RESULTS

There were no postoperative deaths and no clinical anastomotic leaks in the lavage group. The duration of hospital stay (median 11 days) was similar in both groups (overall and sigmoid resection respectively). In the Hartmann group, there were two deaths and the postoperative stay in hospital was significantly longer.

CONCLUSIONS

Primary resection with intraoperative lavage can be done successfully in patients with acute obstruction of the left colon and the duration of hospital stay and morbidity are similar to those seen in patients operated on electively.