Evaluation of the middle and inner ear structures: comparison of hybrid rendering, virtual endoscopy and axial 2D source images

Recent developments in 3D reconstructions can enhance the quality and diagnostic value of axial 2D image data sets with direct benefits for clinical practice. To show the possible advantages of a hybrid rendering method [color-coded 3D shaded-surface display (SSD)- and volume rendering method] with the possibility of virtual endoscopy we have specifically highlighted the use in relation to the middle and inner ear structures. We examined 12 patients with both normal findings and postoperative changes, using image data sets from high-resolution spiral computed tomography (HRSCT). The middle and inner ear was segmented using an interactive threshold interval density volume-growing method and visualized with a color-coded SSD rendering method. The temporal bone was visualized using a transparent volume rendering method. The 3D- and virtual reconstructions were compared with the axial 2D source images. The evaluated middle and inner ear structures could be seen in their complete form and correct topographical relationship, and the 3D- and virtual reconstructions indicated an improved representation and spatial orientation of these structures. A hybrid and virtual endoscopic method could add information and improve the value of imaging in the diagnosis and management of patients with middle or inner ear diseases making the understanding and interpretation of axial 2D CT image data sets easier. The introduction of an improved rendering algorithm aids radiological diagnostics, medical education, surgical planning, surgical training, and postoperative assessment. Received: 22 July 1998; Revised: 15 April 1999; Accepted: 19 April 1999     

Imaging breasts with silicone implants

Over the last two decades, the use of breast implants both for breast augmentation and for breast reconstruction following mastectomy has increased substantially. It is estimated that around two million women have undergone breast augmentation, while hundreds of thousands have had breast reconstruction surgery. Different types of material have been used for breast implants, but silicone gel implants have been the dominating implant type. Many implants can lead to complications, such as hardening and rupture, and may therefore need in vivo evaluation by imaging, particularly if they lead to clinical symptoms. They can also pose problems in the assessment of surrounding breast tissue by conventional mammography. In this respect, imaging modalities such as ultrasound, computed tomography and magnetic resonance imaging offer greater possibilities to assess a failing implant, as well as surrounding breast tissue. Several factors, mainly of a psychological nature, lead to requests for breast implants. In this review article, only the imaging aspects of breasts with silicone gel implants will be dealt with. Each modality is concisely presented with its possibilities and limitations. Received: 5 February 1998; Revision received: 18 May 1998; Accepted: 25 May 1998     

Effect of magnolol on in vitro mitochondrial lipid peroxidation and isolated cold-preserved warm-reperfused rat livers

BACKGROUND/AIM: A mechanism suggested to cause injury to preserved organs is the generation of oxygen free radicals. Lipid peroxidation is one of the biological damages caused by oxygen free radicals. It is our aim to investigate whether magnolol, a strong antioxidant, suppresses the generation of oxygen free radicals and improves the viability of cold-preserved warm-reperfused rat livers. MATERIALS AND METHODS: In vitro lipid peroxidation was induced in rat hepatic mitochondria with ADP and FeSO4. The inhibitory effect of magnolol on lipid peroxidation was measured with oxygen consumption and malondialdehyde (MDA) formation. Subsequently, we preserved and reperfused rat livers in preservation solutions that contained magnolol. The hepatic enzymes and liver MDA were measured to assess the protective effect of magnolol on isolated rat livers. RESULTS: In rat hepatic mitochondria, magnolol was 470 times more potent than alpha-tocopherol in inhibiting oxygen consumption and 340 times more potent than alpha-tocopherol in inhibiting MDA formation. Addition of magnolol to Ringer's lactate solution had a protective effect, in terms of MDA formation and leakage of hepatic enzymes, on warm-reperfused but not cold-stored liver tissue. Addition of magnolol to University of Wisconsin (UW) solution, a widely used preservation solution, did not modify the effect of this solution on isolated liver tissues. CONCLUSIONS: We conclude that magnolol is an effective antioxidant and suppresses lipid peroxidation in rat liver mitochondria and can be used as a rinsing solution in protecting transplanted organs from lipid peroxidation during reperfusion, especially for those organs not preserved with UW solution.     

A new factor Xa inhibitor (lefaxin) from the Haementeria depressa leech

The salivary complex of the leech Haementeria depressa produces potent anticoagulant components. Among them, a protein named lefaxin inhibits factor Xa (FXa). Lefaxin was purified to homogeneity from dissected salivary complexes by gel filtration in Sephadex G-150 followed by two ion exchange chromatography steps in Mono-Q. Inhibition of FXa by lefaxin was demonstrated by the inhibition of its amidolytic activity, measured with chromogenic substrate S-2765 (apparent K(I) of 4 nM), and of its ability to inhibit thrombin generation in the prothrombinase complex (EC50 of 40 nM). Lefaxin has a molecular weight of 30 kDa and an isoelectric point of 5.7. It is made of a polypeptide chain whose N-terminal sequence shows no similarity with that of other FXa inhibitors (antistasin and ghilianten) isolated from leech saliva. On the other hand, the N-terminal sequence of lefaxin presents significant sequence similarity with nitric oxide carrier proteins myohemerythrin from the annelid Nereis diversicolor and prolixin S from the triatoma Rhodnius prolixus. Interestingly, prolixin S also proved to be an anticoagulant protein acting on FXa.     

Perfusion sphincterometry for objective evaluation of postprostatectomy intrinsic sphincter deficiency

OBJECTIVES: Male urinary incontinence secondary to intrinsic sphincter deficiency (ISD) is a possible complication of transurethral resection of the prostate (TURP) or radical prostatectomy (RP). For objective assessment of urinary sphincteric competence, we used perfusion sphincterometry (PS) to measure the retrograde urethral perfusion pressure (RUPP). METHODS: A retrospective and prospective analysis of 60 neurologically normal patients of varying continence status was performed. The subjects were divided into three groups: continent patients with no previous prostate surgery (group 1), continent patients after prostatectomy (group 2), and incontinent patients after prostatectomy (group 3). All patients underwent PS with the technique described. All incontinent patients (group 3) had a filling cystometrogram (CMG) to rule out detrusor instability. RESULTS: Continent patients with no prior prostate surgery (group 1) had a mean RUPP of 101 +/- 16 cm H2O; continent postprostatectomy patients (group 2) had a mean RUPP of 77 +/- 14 cm H2O; and incontinent postprostatectomy patients (group 3) had a mean RUPP of 36 +/- 11 cm H2O. The differences were statistically significant (P <0.001). There was no statistically significant difference in RUPP when the patients in groups 2 and 3 were stratified into TURP and RP groups. CONCLUSIONS: PS is a simple and accurate technique for objective evaluation of lower sphincter competence. Patients with stress incontinence after prostatectomy have a statistically significant decrease in RUPP compared with continent controls. In combination with cystourethroscopy and filling CMG, PS can be useful in the evaluation of postprostatectomy incontinence.     

Tissue potassium,selenium, and iron levels associated with gastric cancer progression

The contents of 10 minor and trace elements in histologically confirmed gastric adenocarcinomas and their corresponding normal gastric mucosal tissues obtained from 39 patients at the time of gastric resection were simultaneously determined by instrumental neutron activation analysis. Specimens were irradiated by reactor neutrons and subsequently subject to direct analysis using a high-resolution HPGe -spectrometer. Univariate analysis revealed that gastric cancer tissues had significantly higher concentrations of Fe, K, Mg, Na, Rb, Se, and Zn than normal gastric mucosal tissues. However, multivariate analysis found that Fe, K, and Se were independent elements that associated with gastric cancer. Upon further evaluation of their clinical significance, we found a high tissue K level was related to lymphatic duct metastasis. High Se tissue levels were linked to intestinal type adenocarcinoma. A positive correlation was found between high Fe levels and vascular involvement. These findings suggest that Fe and K are associated with gastric cancer progression. Se is involved in carcinogenesis of stomach in high-risk areas. The mechanisms that underlie the corresponding pathohistological features deserve further study.     

Surgical Mortality, Survival, and Quality of Life after Resection for Gastric Cancer in the Elderly

Although there were some studies on clinicopathologic characteristics, operative morbidity, and mortality in elderly patients with gastric cancer, no reports have specifically focused on survival and quality of life after resection. A total of 433 patients aged ≥ 65 years (1987–1994) who underwent gastric resection for gastric adenocarcinoma were studied. Two groups were considered: patients aged 65 to 74 years and those > 74 years. Most of the patients (78.1%) had advanced diseases, and nearly half (41.3%) had associated chronic disease(s). Resections with curative intention were performed in 362 patients (83.6%). The overall operative morbidity rate was 21.7% and mortality rate 5.1%. Although operative procedures were similar in both groups, patients aged >74 years had a higher mortality rate than those aged 65 to 74 years (10.1% vs. 3.5%; p= 0.034). Age and extent of gastric resection were two independent factors negatively affecting mortality. The cumulative survival rates for patients who underwent curative resection were 86.2%, 72.4%, 67.2%, 62.9%, and 60.0% at 1, 2, 3, 4, and 5 years, respectively. Nearly all patients (96%) after surgery had normal work and daily activities. Some patients appeared to lack energy (16%) or experienced a period of anxiety or depression. There was no statistical difference in survival and quality of life assessed by the Spitzer index after curative resection between the two groups. Therefore resection with curative intention can be performed for the elderly with acceptable morbidity and mortality rates, possible long-term survival, and good quality of life, but a limited operation should be considered in the very elderly patients.     

Crotoxin acceptor protein isolated from Torpedo electric organ: binding properties to crotoxin by surface plasmon resonance.

Crotoxin, a potent neurotoxin from the South American rattlesnake Crotalus durissus terrificus, is a heterodimeric phospholipase A(2) (EC 3.1.1.4), which blocks the release of acetylcholine from peripheral neurons. We previously have suggested the existence of a 48 kDa crotoxin-binding protein in the presynaptic membranes of the electric organ of Torpedo marmorata. Here, we report the purification and characterization of this protein that we called the crotoxin acceptor protein from Torpedo (CAPT). The membranes of electric organs from Torpedo were solubilized with a detergent (4% (w/v) Triton X-100) and CAPT was isolated by affinity chromatography on a crotoxin column. SDS-PAGE showed that the purified protein was homogeneous and cross-linking studies with radioiodinated crotoxin confirmed that it had retained its toxin-binding properties. The purified CAPT has similar molecular mass as crocalbin, a crotoxin-binding protein isolated from porcine brains, yet anti-crocalbin antiserum failed to recognize CAPT. Surface plasmon resonance biosensor technology was used to measure the specific interaction between crotoxin and solubilized CAPT. Using this method, it was possible to follow CAPT throughout the purification procedure. As well, an apparent dissociation constant (K(d)(app)) of 3.4 nM was calculated for the interaction of pure CAPT and crotoxin from the dissociation rate constant (k(off)=1.2 x 10(-2)s(-1)) and the association rate constant (k(on)=3.5 x 10(6)M(-1)s(-1)).     

Prospective Study of Gastric Outlet Obstruction in Unresectable Periampullary Adenocarcinoma

Controversy persists regarding the role of prophylactic gastrojejunostomy in patients with unresectable periampullary adenocarcinoma. In review of the retrospective series, presence of gastric outlet obstruction (GOO) has been claimed to be a bad prognostic sign. This prospective study aimed to clarify the necessity of routine prophylactic gastrojejunostomy in patients with unresectable periampullary adenocarcinoma. The incidence and prognostic significance of GOO were also evaluated. Sixty-six patients with unresectable periampullary adenocarcinoma were enrolled. They were divided into 2 groups to receive either a single biliary bypass or a double bypass (concomitant gastric and biliary bypasses) if they had GOO. The single bypass group was followed up to assess the incidence of GOO and subsequent need of a gastric bypass. Prognostic factors were evaluated by univariate and multivariate analyses. Forty-four (67%) of the overall 66 patients presented with GOO at the time of diagnosis. There was no statistical difference regarding the morbidity and mortality between the 2 groups, except longer (7 days) hospital stay in the double bypass group. Seven (31.8%) of the 22 patients in the single bypass group subsequently developed GOO an average of 6.2 ± 1.0 months after their initial biliary bypass. By univariate analysis, significant prognostic factors for unresectable periampullary adenocarcinoma were: GOO (p= 0.0379), pancreatic head origin (p= 0.0146 by univariate analysis), and distant metastasis (p < 0.0001). After multivariate analysis, only pancreatic head origin and distant metastasis remained significant independent factors of poor prognosis. In conclusion, gastrojejunostomy should be performed prophylactically in addition to a biliary bypass in patients with unresectable periampullary adenocarcinoma. The presence of GOO is not an independent factor of poor prognosis, but a reflection of the aggressive biologic behavior of pancreatic head adenocarcinoma.