Polyp detection with MDCT: a phantom-based evaluation of the impact of dose and spatial resolution

OBJECTIVE: The objective of our study was to evaluate the impact of dose and spatial resolution on the detection of colonic polyps using a 4-MDCT scanner. MATERIALS AND METHODS: Twenty-four latex phantoms that simulate the large bowel and contain artificial polyps of different sizes and shapes were constructed. The polyps were divided into three size groups (diameter, 0-2, 2-5, and 5-10 mm) and were classified into four shape groups: pedunculated; broad-based; ulcerated or depressed; and sessile or flat. The colon phantoms were submerged in a water tank and scanned on a 4-MDCT scanner using 12 protocols with various settings of slice thickness, pitch, and tube current. The images were independently evaluated by three radiologists using axial 2D multiplanar reconstruction images and a 3D surface-rendering technique (fly-through). RESULTS: At a constant dose (i.e., dose-length product [DLP]), the polyp detection rate increased with increasing axial spatial resolution. For the standard protocol (2.50-mm slice thickness, 1.5 pitch), the detection rate for all polyp sizes decreased from approximately 70% at 100 mA to 55% at 40 mA. Between a 60- and 100-mA tube current, the detection rate for the largest polyps (> 5 mm) was almost constant, close to 90%. CONCLUSION: The detection of polyps in the large bowel using a standard protocol can be improved without dose penalty by increasing the axial spatial resolution of the image acquisition and adjusting the tube current setting. If the analysis can be restricted to polyps larger than 5 mm, the dose can be substantially reduced without compromising the detection rate.     

Skin toxicity as a risk factor for major infections in breast cancer patients treated with docetaxel

Docetaxel-related skin toxicity, oral and gastrointestinal mucosal toxicity, and changes in blood cell counts were investigated as predictive factors for major infections in 143 women treated with 3-weekly docetaxel (100 mg/m²) as second-line therapy for metastatic breast cancer in a randomized trial. Each patient with a major infection (n=37) was compared with two controls. Skin toxicity (odds ratio 2.97, 95% CI 1.37-6.47), oral mucositis (1.98, CI 1.30-3.04), and the leukocyte nadir (0.12, CI 0.02-0.51) were significantly associated with a major infection in a univariate logistic regression analysis. In a multivariate analysis, skin toxicity was the only independent factor predictive for grade 3 to 4 infection (2.75, CI 1.00-7.58). A major infection was diagnosed in 62% (8 out of 13) of the docetaxel cycles in severely (grade 4) leukopenic patients who had grade 2 to 4 skin toxicity. Major infections are common in leukopenic patients who develop docetaxel-associated skin toxicity, and leukopenic patients presenting with docetaxel-induced skin toxicity may be candidates for prophylactic anti-infection measures such as prophylactic therapy with hematopoietic growth factors.     

Tamoxifen treatment reverses the adverse effects of chemotherapy-induced ovarian failure on serum lipids

In all, 146 premenopausal women with early stage breast cancer were treated with adjuvant chemotherapy. In addition, 5-year tamoxifen treatment was started after chemotherapy to those 112 patients with hormone-receptor-positive tumours while those with hormone-receptor-negative tumours received no further therapy. The serum lipid levels were followed in both groups. The levels of serum total and low-density lipoprotein (LDL) cholesterol increased significantly after chemotherapy only in patients who developed ovarian dysfunction. Total cholesterol increased +9.5% and LDL cholesterol +16.6% in patients who developed amenorrhoea (P<0.00001 and 0.00001, respectively). The cholesterol levels did not change in patients who preserved regular menstruation after chemotherapy. After 6 months of tamoxifen therapy, the total cholesterol decreased -9.7% and the LDL cholesterol -16.7% from levels after the chemotherapy, while the cholesterol concentrations remained at increased levels in the control group (P=0.001 and P<0.0001, respectively). The high-density lipoprotein cholesterol levels did not change significantly in either tamoxifen or control group. The effects of tamoxifen treatment on serum lipids after chemotherapy have not been studied before. Our current study suggests that adjuvant tamoxifen therapy reverses the adverse effects of chemotherapy-induced ovarian failure on total and LDL cholesterol and even lowers their serum levels below the baseline.     

Impact of choice of therapeutic strategy for acute cholecystitis on patient's health-related quality of life. Results of a randomized, controlled clinical trial

BACKGROUND: The aim of this prospective, randomized study was to determine if health related quality of life is affected by the choice of surgical strategy in the management of acute cholecystitis. MATERIAL AND METHODS: After diagnostic workup, patients were randomized to one of two groups: (1) early laparoscopic cholecystectomy (i.e. within 7 days after onset of symptoms) or (2) initial conservative treatment followed by delayed laparoscopic cholecystectomy. Seventy-four patients entered the early operation group and 71 patients were assigned to the delayed operation strategy. Assessments of quality of life were made at 1, 3 and 6 months after surgery, and in the delayed operation group also one month after the initial conservative treatment. RESULTS: The gastrointestinal symptom scores were significantly better in three dimensions (diarrhea, indigestion, abdominal pain) one month after surgery for the acute operation group (p < 0.01). Three and 6 months after the operation we were unable to detect any significant differences between the groups. The patients in the delayed operation group did not appear to suffer from more symptoms in the period of time waiting for their elective operation. Psychological general well-being showed no major differences between the groups. CONCLUSION: Cholecystectomy in the acute phase of acute cholecystitis offers a significant reduction of gastrointestinal symptoms during the first postoperative month and to that associated improved quality of life in this group of patients.     

C-11-labeled glucose and its utilization in positron-emission tomography

Carbon-11-labeled glucose was prepared photosynthetically using the green alga Scenedesmus obtusiusculus Chod. The carbohydrates were extracted from the cells with dilute HCI and the glucose was isolated and purified using high-performance liquid chromatography. The manipulations in the hot cell are described. Analysis of the material (gas liquid chromatography and HPLC) showed that the glucose obtained was radiochemically pure. The total incorporation of the 11CO2 added to the algae was 60-80%. The radiochemical yield of pure carrier-added glucose was approximately 25%, at 40 min after E.O.B. including the HPLC purification and sterile filtration. The C-11 glucose uptake in rat brain was compared with that of commercial D[U-14C]glucose, and preliminary PET studies with D-[11C]glucose in a patient with a brain infarct are presented.     

P wave changes during exercise in normal subjects and in patients with hemodynamic evidence of left atrial overload

P wave characteristics at rest and during exercise in normal subjects and patients with hemodynamic evidence of left atrial overload were compared. Three groups were studied, including 48 normal subjects, 15 patients with mitral stenosis, and 24 patients with left ventricular dysfunction. Frank lead electrocardiograms were recorded on magnetic tape at rest sitting and during upright bicycle exercise. Digital computer techniques were used to derive P wave area vectors. The initial 3/8 of the P wave were regarded as representing primarily right atrial, and the terminal 5/8 primarily left atrial activity.The P wave response to exercise in normal subjects include a small but significant (p<0.005) increase of the vertical component of the initial or right atrial vector and a significant (p<0.001) increase of the posterior terminal P vector component from 0.5 to 1.1 μV-sec.Analysis of area vectors in the abnormal groups at rest increased the recognition rate of left atrial overload over that obtained with standard 12-lead criteria, from 38 to 82% (P<0.005) at a specificity of 92%. The recognition rate during exercise was 67%, slightly lower than that at rest, due to increased inter-individual variation and exercise-induced changes in the normal group in the direction of the left atrial overload.     

Adjuvant hormone therapy in breast cancer.

Recent results from controlled trials of adjuvant tamoxifen and oophorectomy in early breast cancer are reviewed. The results of the statistical overview performed by the Early Breast Cancer Trialists Collaborative Group are summarised, and some important questions left open by this overview are discussed. These include the choice of patients for adjuvant endocrine treatment, long term results of tamoxifen, interaction with postoperative radiotherapy, the effect of tamoxifen on non-cancer deaths, and interaction of the adjuvant effect of tamoxifen with concentrations of oestrogen receptor levels in the tumour.     

Ethanol-induced locomotor activity: involvement of central nicotinic acetylcholine receptors?

Ethanol and nicotine have many psychopharmacological effects in common, which could explain why coadministration of these compounds often is observed in individuals. In the present study in mice, low doses of nicotine in a complex manner altered the locomotor activity (LMA) stimulatory effect of different doses of ethanol, whereas the quaternary nicotine analog tetramethylammonium did not. The blood-brain-barrier-penetrating nicotine antagonist mecamylamine (2.0 and 4.0 mg/kg), but not the quaternary nicotine antagonist hexamethonium (4.0 and 8.0 mg/kg), partly counteracted the LMA stimulatory effect of ethanol (3.0 g/kg) in doses having no LMA reducing effects per se. Furthermore, the dihydroxyphenylacetic acid (DOPAC)/dopamine (DA) quotient increase in mouse brain after ethanol 3.0 g/kg was partly antagonized by mecamylamine 2.0 and 4.0 mg/kg. These results suggest that part of the LMA and DA turnover-increasing effect of ethanol is mediated via activation of central nicotinic acetylcholine receptors.     

Lamina I spinocervical tract terminations in the medial part of the lateral cervical nucleus in the cat.

The terminations of spinocervical tract fibers in the lateral cervical nucleus (LCN) of the cat were examined with anterogradely transported Phaseolus vulgaris leucoagglutinin (PHA-L) in order to analyze their organization relative to the most medial part and the main body (the lateral two-thirds) of the LCN, which have differential projections and physiological characteristics. Iontophoretic injections of PHA-L in laminae I-V of the spinal dorsal horn yielded dense labeling in somatotopically appropriate regions of the main body of the LCN, and, as seen previously with horseradish peroxidase, additional terminations were present in the medial LCN after injections at either cervical or lumbar spinal levels. The morphological characteristics of the PHA-L labeling in these two parts of the LCN were different. Terminations in the lateral LCN consisted of dense clusters of thick fibers bearing large numbers of boutons. The terminal axons in the medial part of the LCN displayed a reticulated network of longitudinally oriented, fine fibers with well-spaced varicosities. Some of the fine fibers in the medial LCN appeared to be collaterals of thicker fibers that terminated in the lateral LCN. Injections of PHA-L that were restricted to lamina I resulted in terminal labeling only in the medial LCN. The labeling was more sparse than that observed in the medial LCN after larger dorsal horn injections but displayed the same morphological characteristics. Lamina I terminations were seen in the medial LCN after cervical or lumbar injections on both the ipsilateral and contralateral sides. The PHA-L observations were corroborated by the presence of many retrogradely labeled lamina I cells at both cervical and lumbar spinal levels, following injections of cholera toxin subunit b or rhodamine-labeled microspheres in the medial LCN. In addition, double-immunofluorescent labeling for PHA-L and substance P was performed in a few cases, since substance P immunoreactivity is present in fibers in the medial LCN and also in cell bodies in lamina I; however, very few spinocervical fibers displayed immunoreactivity for both antigens. These observations indicate that the medial part of the LCN receives input from lamina I neurons, and probably from lamina III-V neurons as well, at cervical and lumbar spinal levels. The lamina I input to the medial LCN provides a basis for the small population of nociceptive neurons that differentiate the medial LCN. The lamina I input could also be responsible for the general inhibition of lateral LCN neurons by wide-field noxious stimulation, via activation of GABAergic interneurons in the medial LCN.(ABSTRACT TRUNCATED AT 400 WORDS)     

Distribution of growth hormone receptor mRNA in the brain stem and spinal cord of the rat

By using in situ hybridization histochemistry the distribution of growth hormone (GH) receptor mRNA was examined in the rat brain stem and spinal cord. Dense labeling was seen in the arcuate nucleus of the hypothalamus, as reported previously, but also in several other areas, including the locus coeruleus, the area postrema, and the commissural part of the nucleus of the solitary tract. Other labeled structures included the superior lateral parabrachial nucleus, the facial, hypoglossal and trigeminal motor nuclei, the nucleus incertus, the dorsal tegmental nucleus, the dorsal raphe nucleus, the nucleus of the trapezoid body, and the superficial layers of the dorsal horn of the spinal cord. These findings provide support for a direct action of GH on brain regions involved in various aspects of homeostatic control. Thus, the distribution of GH receptor mRNA to visceral sensory and motor structures is consonant with a role of GH in the regulation of food intake and energy homeostasis. Its presence in the superficial dorsal horn of the spinal cord indicates a role for GH in the initial processing of fine afferent input, and may help explain the beneficial effects of GH replacement in certain unclear pain conditions.