Rapid and accurate determination of tissue optical properties using least-squares support vector machines

Diffuse reflectance spectroscopy (DRS) has been extensively applied for the characterization of biological tissue, especially for dysplasia and cancer detection, by determination of the tissue optical properties. A major challenge in performing routine clinical diagnosis lies in the extraction of the relevant parameters, especially at high absorption levels typically observed in cancerous tissue. Here, we present a new least-squares support vector machine (LS-SVM) based regression algorithm for rapid and accurate determination of the absorption and scattering properties. Using physical tissue models, we demonstrate that the proposed method can be implemented more than two orders of magnitude faster than the state-of-the-art approaches while providing better prediction accuracy. Our results show that the proposed regression method has great potential for clinical applications including in tissue scanners for cancer margin assessment, where rapid quantification of optical properties is critical to the performance.     

Narrow-band pass filter array for integrated opto-electronic spectroscopy detectors to assess esophageal tissue

A strategy for spectroscopy tissue diagnosis using a small number of wavelengths is reported. The feasibility to accurately quantify tissue information using only 16 wavelengths is demonstrated with several wavelength reduction simulations of the existing esophageal data set. These results are an important step for the development of a miniaturized, robust and low-cost spectroscopy system. This system is based on a sub-millimeter high-selective filter array that offers prospects for a simplified miniature spectrographic detector for a future diagnostic tool to improve the diagnosis of dysplasia. Several thin-film optical filters are optimized and fabricated and its spectral performance is shown to be sufficient for the selection of specific wavelength bands.     

Future strategies for the treatment of diastolic heart failure

It is estimated that 30% to 50% of heart failure patients have preserved systolic left ventricular (LV) function, often referred to as diastolic heart failure (DHF). Mortality is high in this patient population, and morbidity and rate of hospitalization are similar to those of patients with systolic heart failure. The management of patients with diastolic heart failure is essentially empirical, limited, and disappointing. New drugs, devices, and gene therapy based treatment options are currently under investigation. In this review, future strategies for the treatment of diastolic heart failure are discussed.     

Costs of health care for irritable bowel syndrome, chronic constipation, functional diarrhoea and functional abdominal pain

AIM: To provide estimates of actual costs to deliver health care to patients with functional bowel disorders, and to assess the cost impact of symptom severity, recency of onset, and satisfaction with treatment. METHODS: We enrolled 558 irritable bowel (IBS), 203 constipation, 243 diarrhoea and 348 abdominal pain patients from primary care and gastroenterology clinics at a health maintenance organization within weeks of a visit. Costs were extracted from administrative claims. Symptom severity, satisfaction with treatment and out-of-pocket expenses were assessed by questionnaires. RESULTS: Average age was 52 years, 27% were males, and 59% participated. Eighty percent were seen in primary care clinics. Mean annual direct health care costs were $5049 for IBS, $6140 for diarrhoea, $7522 for constipation and $7646 for abdominal pain. Annual out-of-pocket expenses averaged $406 for treatment of IBS symptoms, $294 for diarrhoea, $390 for constipation and $304 for abdominal pain. Lower gastrointestinal costs comprised 9% of total costs for IBS, 9% for diarrhoea, 6.5% for constipation and 9% for abdominal pain. In-patient care accounted for 17.5% of total costs (15.2% IBS). CONCLUSION: Costs were affected by disease severity (increased), recent exacerbation of bowel symptoms (increased), and whether the patient was consulting for the first time (decreased).     

Pamidronate treatment in rheumatology practice: a comprehensive review

Pamidronate, along with other bisphosphonates, has been used for treatment of bone pain secondary to malignant involvement or metastatic disease for years. Some data, however, have also accumulated on the utility of pamidronate in a variety of benign conditions frequently handled by rheumatologists. This study aims to review the available published data regarding the potential use of pamidronate in rheumatology practice. Methods include the review of relevant articles retrieved by a PUBMED search utilizing the index term “pamidronate”. All available randomized control trials, open trials, and case series, as well as properly reported case studies evaluating usage of pamidronate in rheumatic disorders, have been included in the literature review. The efficacy of pamidronate in patients with spondyloarthropathies; synovitis, acne, pustulosis, hyperostosis, and osteitis syndrome; hypertrophic osteoarthropathy; osteoporotic vertebral fractures; chronic back pain due to disk disease or spinal stenosis; Charcot arthropathy; transient osteoporosis; and complex regional pain syndrome-I, has been demonstrated in more than 40 reports, the majority of which, however, were not controlled studies. In some of reviewed conditions, aside from providing analgesic relief, pamidronate may also have disease-modifying properties. While used in different doses in a variety of rheumatic disorders, pamidronate was generally reported to be well tolerated with an overall good safety profile. Pamidronate may represent an effective and safe choice for a spectrum of rheumatic patients, suffering from intractable musculoskeletal pain, unresponsive to traditionally recommended therapies. Large randomized, controlled studies examining the efficacy of pamidronate in the rheumatic conditions are urgently needed.     

Response Entropy Is More Reactive Than Bispectral Index During Laparoscopic Gastric Banding

Objective. There is a potential use for spectral entropy or bispectral index (BIS) for controlling level of anesthesia, but it is not known how these EEG monitors relate during steady state anesthesia. We compared Response Entropy (RE) and BIS during anesthesia for laparoscopic gastric banding with RE targeted to 45. Methods. Forty patients undergoing laparoscopic gastric banding were randomly assigned to receive either fentanyl or dexmedetomidine infusion, with desflurane concentration adjusted to maintain RE at 45. During anesthesia the average RE and BIS was determined in each patient and the RE-BIS difference plotted as a function of RE every 10 seconds. Fifteen of 40 patients showed activation of RE above 60 during surgery. In these patients RE, BIS and the electromyogram (EMG) were evaluated for the period 10 minutes before and including the peak change in RE. Results. In fentanyl and dexmedetomidine treated patients the average RE was 44–47 with no statistical difference between anesthesia groups or between RE and BIS. In each patient there was a linear relationship between the RE-BIS difference and RE during anesthesia. RE and BIS were similar at a level of 41–44 and RE showed a greater range at higher and lower values compared to BIS. When RE activation was identified during surgery in 15 patients, it was associated with an increase in BIS and EMG. Conclusion. Within the range of 41–44, RE and BIS are equal but the gain of RE is 0.5 greater than BIS with deeper or lighter anesthesia. This is not likely due to increased smoothing with BIS. Identifying periods of RE activation show that BIS, EMG and RE increase together.Feld J, Hoffman WE Park H. Response entropy is more reactive than bispectral index during laparoscopic gastric banding.     

Expansion of elderly couples' IADL caregiver networks beyond the marital dyad

Factors influencing expansion of instrumental activities of daily living (IADL) caregiver networks beyond the spouse/partner were studied, using data from the Asset and Health Dynamics among the Oldest Old (AHEAD) nationally representative sample of American elders (ages 70 and older). Analyses were based on 427 Black and White couples in which one partner regularly received IADL assistance; nearly 20% had expanded networks. Logistic regression showed expanded networks were significantly more likely when spouses had IADL or basic personal activity of everyday living (ADL) limitations and help recipients were wives or had numerous IADL or ADL limitations; they also tended to be more common (p <.10) for couples with numerous nearby daughters and help recipients with proxies and those without serious cognitive problems. Network expansion was unrelated to recipients' number of health conditions and Medicaid coverage or couples' ages, marital duration, income, and number of proximate sons. Implications for service programs and caregiving theories of the circumstances linked to IADL assistance from outside the marital dyad are discussed.     

Abnormal Intestinal Permeability in Primary Biliary Cirrhosis

Antimitochondrial antibodies (AMAs) found in patients with primary biliary cirrhosis (PBC) cross-react with bacterial proteins and hence molecular mimicry has been proposed as a mechanism for AMA development. Alterations in gastrointestinal permeability would provide a potential route for increased exposure of gut flora to the immune system. In this study we aimed to compare the measured gastrointestinal permeability in patients with PBC to that in patients with liver disease (hepatitis C) and healthy control populations. Subjects drank a mixture of sucrose, lactulose, and mannitol dissolved in water. Eight-hour urinary excretion of the sugars was measured to assess intestinal permeability. Antiendomysial antibody testing was performed to exclude subclinical celiac disease. Eighty-six patients with PBC were evaluated and compared to 69 hepatitis C patients and 155 healthy controls. The mean urinary excretion of sucrose in the PBC patients (133.89 ± 72.56 mg) was significantly higher than that in hepatitis C patients (101.07±63.35) or healthy controls (89.46±41.76) (P=0.0001), suggesting abnormal gastric or proximal small intestinal permeability. Sucrose excretion was not increased among patients with hepatitis C compared to healthy controls. The ratio of lactulose:mannitol excretion, reflecting small bowel permeability, was also elevated in the PBC group (0.017±0.012) compared to healthy controls (0.012±0.007) (P=0.0001) but was equal to that found among patients with hepatitis C (0.016±0.011) (P=NS). We conclude that the permeability of both the stomach and the small bowel is increased in patients with PBC, however, it is unclear if it is a cause, consequence, or manifestation of the disease.     

Comparison of unenhanced and contrast-enhanced spiral CT for assessing interval change in patients with colorectal liver metastases

RATIONALE AND OBJECTIVES: The purpose of this study was to determine whether the interval change in hepatic colorectal metastases as assessed with serial computed tomographic (CT) scans without contrast material enhancement differs from that as assessed using serial, portal dominant phase, contrast-enhanced CT scans. MATERIALS AND METHODS: Unenhanced and contrast-enhanced abdominal CT scans were obtained in 28 patients. Three radiologists separately reviewed serial unenhanced and contrast-enhanced studies to assess the interval change in liver metastases. These radiologists recorded total number of lesions, bidimensional measurements of the largest lesions (as many as three), and overall impressions regarding the interval change (none, worse, or better). RESULTS: Among the 84 judgments (28 patients x 3 radiologists), comparisons of unenhanced and contrast-enhanced CT studies were concordant in 60 assessments (71%). Nineteen (23%) showed mild disagreement. Of these, contrast-enhanced CT studies demonstrated disease stability when unenhanced CT studies demonstrated otherwise in 11 judgments, whereas unenhanced CT studies demonstrated stability when contrast-enhanced CT studies demonstrated otherwise in eight assessments. Furthermore, of the five marked disagreements, two resulted from a conclusion of interval improvement on unenhanced CT studies and a conclusion of interval worsening on contrast-enhanced CT studies, whereas three demonstrated the opposite. Neither set of serial CT studies systematically resulted in under- or overestimation of disease progression (McNemar Q test, P < .25). CONCLUSION: The authors found no consistent pattern to demonstrate that serial unenhanced or contrast-enhanced CT studies resulted in over- or underestimation of disease progression.