Hematite-coated microfossils: primary ecological fingerprint or taphonomic oddity of the Paleoproterozoic?

Microfossils belonging to the 1.88-billion-year-old 'Gunflint-biota' are preserved as carbonaceous and hematitic filaments and spheres that are believed to represent ancient chemolithoautotrophic Fe(II) oxidizing bacteria that grew above a chemocline where ferruginous seawater upwelled into shallow, oxygenated waters. This 'biological' model posits that hematite formed during burial from dewatering of the precursor ferric oxyhydroxides that encrusted Fe(II)-oxidizing bacteria. Here, we present an alternate 'taphonomic' model in which iron-rich groundwaters discharged into buried stromatolites; thus, the mineralization reactions are more informative of diagenetic processes than they are for primary marine conditions. We sampled centimeter-scale columnar stromatolites from both the lower and upper stromatolite horizons of the Biwabik and Gunflint formations, across a range of metamorphic gradients including unaltered to prehnite-pumpellyite taconite, supergene altered ore, and amphibolite-pyroxene grade contact-metamorphic zones. Fossils are rare to very rare and comprise curved filaments that exist in clusters with similar orientations. The filaments from throughout the Biwabik are similar to well-preserved carbonaceous Gunflintia from Ontario. Spheres of Huroniospora are also found in both formations. Microfossils from the least altered sections are preserved as carbon. Prehnite-pumpellyite samples are composed of either carbon or hematite (Fe2 O3 ). Within the contact aureole, filaments are densely coated by magnetite (Fe3 O4 ); the highest grade samples are secondarily oxidized to martite. The consistency in stromatolite microstructure and lithofacies throughout the metamorphic grades suggests they formed under similar environmental conditions. Post-depositional alteration led to replacement of the carbon by iron oxide. The facies association, filament distribution, and lack of branching and attached spherical cells argue against Gunflintia being a direct analogue to common marine, chemolithoautotrophic Fe(II)-oxidizing bacteria. Instead, we propose that the presence of hematite-coated microfossils is a reflection of taphonomic processes and does not necessarily reflect the byproduct of an original microbial ecosystem.

7th International Immunoglobulin Conference: Immunoglobulin in clinical practice

Intravenous and subcutaneous immunoglobulins (IVIg and SCIg, respectively) are increasingly used in clinical practice, not only as replacement therapy but also for immunomodulation. Physicians have learned that primary immunodeficiency (PID) patients are susceptible to recurrent respiratory tract infections even when appropriately treated with immunoglobulin (Ig) therapy. Further investigation will establish whether a combined therapeutic approach including Ig dose optimization will prevent progressive lung disease in PID. The wear-off effects observed with IVIg can be minimized by adjusting the dosing regimen. It is also possible to avoid the cyclic wear-off following transition to SCIg administration. Consideration of benefit versus risk with Ig therapy includes evaluating the potential occurrence of thromboembolic and haemolytic events, which may be more frequent when Ig is administered in high doses and in the presence of pre-existing risk factors. The ability to select an administration method from IVIg, SCIg or hyaluronidase-facilitated SCIg infusions provides patient choice and alternatives if one or other administration route is not suitable for a patient. The evolution in indications, applications, and understanding of Ig therapy described here has reinforced the need for robust methods to prioritize Ig use.

7th International Immunoglobulin Conference: Immunoglobulin in clinical practice

Immunoglobulin (Ig) replacement therapy has been the mainstay of primary immunodeficiencies (PID) treatment for more than 30 years and has substantially changed the lives of patients. This review focuses on aspects of Ig use in clinical practice in addition to discussing prioritizing future Ig use. Despite Ig therapy, PID patients continue to be predisposed to recurrent, subclinical respiratory tract infections, which may lead to chronic lung disease. Research has shown that one of the underlying reasons for this deterioration in lung function is the differential distribution and concentration of Ig isotypes in the airway lumen. Further to this, the relationship between Ig dose and infection outcome is explored, expanding on end-of-cycle loss of efficacy (wear-off) particularly with intravenous immunoglobulin (IVIg), how this can confound the determination of optimal IgG dose and how our aim of treatment should be to improve clinical outcome. This review goes on to discuss the safety of Ig replacement therapy, which is generally well tolerated by most patients, compares the rates of systemic adverse reactions between IVIg and SCIg and highlights the advantages of SCIg administration in this respect, including the use of pre-infused subcutaneous recombinant human hyaluronidase to aid subcutaneous infusion volumes. The growing demand for Ig replacement therapy is challenging physicians; here we show the development of prioritization algorithms to assist in identifying those who will benefit most from this clinically valuable therapy.

Microbial biogeochemistry of Boiling Springs Lake: a physically dynamic, oligotrophic, low-pH geothermal ecosystem

Boiling Springs Lake (BSL) in Lassen Volcanic National Park, California, is North America's largest hot spring, but little is known about the physical, chemical, and biological features of the system. Using a remotely operated vessel, we characterized the bathymetry and near-surface temperatures at sub-meter resolution. The majority of the 1.2 ha, pH 2.2 lake is 10 m deep and 50-52 °C, but temperatures reach 93 °C locally. We extracted DNA from water and sediments collected from warm (52 °C) and hot (73-83 °C) sites separated by 180 m. Gene clone libraries and functional gene microarray (GeoChip 3.0) were used to investigate the BSL community, and uptake of radiolabeled carbon sources was used to assess the relative importance of heterotrophic vs. autotrophic production. Microbial assemblages are similar in both sites despite the strong temperature differential, supporting observations of a dynamic, convectively mixed system. Bacteria in the Actinobacteria and Aquificales phyla are abundant in the water column, and Archaea distantly related to known taxa are abundant in sediments. The functional potential appears similar across a 5-year time span, indicating a stable community with little inter-annual variation, despite the documented seasonal temperature cycle. BSL water-derived DNA contains genes for complete C, N, and S cycles, and low hybridization to probes for N and S oxidation suggests that reductive processes dominate. Many of the detected genes for these processes were from uncultivated bacteria, suggesting novel organisms are responsible for key ecosystem services. Selection imposed by low nutrients, low pH, and high temperature appear to result in low diversity and evenness of genes for key functions involved in C, N, and S cycling. Conversely, organic degradation genes appear to be functionally redundant, and the rapid assimilation of radiolabeled organic carbon into BSL cells suggests the importance of allochthonous C fueling heterotrophic production in the BSL C cycle.

Coupling temperature sensing and development: Hsp90 regulates morphogenetic signalling in Candida albicans

Hsp90 is environmentally contingent molecular chaperone that influences the form and function of diverse signal transducers. Here we discuss our recent findings that Hsp90 regulates the morphogenetic transition from yeast to filamentous forms required for virulence of the most prevalent fungal pathogen of humans, Candida albicans, and does so via cAMP-PKA signalling. This transition is normally regulated by environmental cues that are contingent upon elevated temperature to relieve Hsp90-mediated repression of the morphogenetic program. Intriguingly, Hsp90 inhibition induces filamentation independent of the canonical PKA transcription factor Efg1, in striking similarity to a select set of morphogenetic stimuli. Further investigation will determine the downstream transcription factors through which Hsp90 regulates morphogenesis and the precise mechanism of Hsp90's interaction with the cAMP-PKA pathway. C. albicans is one of many fungal species that undergo a morphological transition in a temperature-dependent manner, thus Hsp90's capacity to govern this key developmental program may provide insight into morphogenesis of diverse organisms.

Subcutaneous immunoglobulin: opportunities and outlook

Immunoglobulin (Ig) administration via the subcutaneous (s.c.) route has become increasingly popular in recent years. The method does not require venous access, is associated with few systemic side effects and has been reported to improve patients' quality of life. One current limitation to its use is the large volumes which need to be administered. Due to the inability of tissue to accept such large volumes, frequent administration at multiple sites is necessary. Most studies conducted to date have investigated the use of subcutaneous immunoglobulin (SCIg) in patients treated previously with the intravenous (i.v.) formulation. New data now support the use of s.c. administration in previously untreated patients with primary immunodeficiencies. SCIg treatment may further be beneficial in the treatment of autoimmune neurological conditions, such as multi-focal motor neuropathy; however, controlled trials directly comparing the s.c. and i.v. routes are still to be performed for this indication. New developments may further improve and facilitate the s.c. administration route. For example, hyaluronidase-facilitated administration increases the bioavailability of SCIg, and may allow for the administration of larger volumes at a single site. Alternatively, more concentrated formulations may reduce the volume required for administration, and a rapid-push technique may allow for shorter administration times. As these developments translate into clinical practice, more physicians and patients may choose the s.c. administration route in the future.

Microcystic features at US: a nonspecific sign for microcystic adenomas of the pancreas

Microcystic adenoma of the pancreas is a benign tumor with no malignant potential and may not require surgery if it is asymptomatic. In the past, a mass containing more than six small (<2-cm) cysts at ultrasonography (US) has been considered to be diagnostic for microcystic adenoma. However, a retrospective study of 36 patients with focal or diffuse pancreatic lesions containing over six small cysts demonstrated that this finding can occur in a wide variety of neoplastic and inflammatory lesions, most of which are malignant. These lesions included adenocarcinoma (n = 18), mucinous cystadenocarcinoma (n = 2), islet cell carcinoma (n = 1), lymphoma (n = 1), sarcoma (n = 1), metastases (n = 2), pancreatitis (n = 4), and adenoma (n = 7). Thus, a finding of multiple small cysts in a pancreatic mass is not specific for microcystic adenoma, and if diagnosis is based on US findings alone, many malignant tumors will be misdiagnosed as microcystic adenomas. Furthermore, computed tomography provides only limited assistance in this setting due to overlapping findings. Needle biopsy can be highly accurate in diagnosing both microcystic adenoma and other malignant lesions and should generally be performed for all lesions with the US features described earlier.

Compound spatial sonography of the thyroid gland: evaluation of freedom from artifacts and of nodule conspicuity

OBJECTIVE

The purpose of this study was to compare compound spatial sonography with conventional sonography of the thyroid gland with respect to freedom from sonographic artifacts and conspicuity of thyroid nodules.

SUBJECTS AND METHODS

A prospective study was performed on 50 thyroid nodules (in 43 patients). Each nodule was examined using compound spatial sonography and conventional sonography. The sonographic techniques were then compared with respect to freedom from sonographic artifacts and thyroid nodule conspicuity.

RESULTS

For freedom from artifacts, compound spatial sonography was superior in 45 cases (90%), and conventional sonography was superior in five cases (10%). Statistical analysis showed that compound spatial sonography was superior to conventional sonography for freedom from artifacts (p < 0.001). For thyroid nodule conspicuity, compound spatial sonography was superior in 37 cases (74%), and conventional sonography was superior in 13 cases (26%). Statistical analysis showed that compound spatial sonography was superior to conventional sonography for thyroid nodule conspicuity (p < 0.001).

CONCLUSION

Compound spatial sonography of the thyroid displays greater freedom from artifacts and better nodule conspicuity than does conventional sonography.

Use of intraoperative Doppler ultrasound to diagnose hepatic venous obstruction in a right lobe living donor liver transplant

Right lobe liver transplantation is a relatively new and technically challenging method of living donor transplantation. Integrity of the hepatic venous anastomosis is crucial for successful transplantation. We describe the use of intraoperative Doppler sonography to diagnose stenosis of the hepatic vein anastomosis, with associated compromise of venous drainage and graft perfusion.

Ethical issues surrounding adult-to-adult living donor liver transplantation

1. The ethical principle of utility is enhanced by living donor liver transplantation (LDLT). LDLT carries the potential to optimize efficient use of organs, minimize pretransplant morbidity and mortality, and increase availability of cadaveric organs. 2. The most serious ethical concerns in LDLT focus on the risks to the donor and relate to the principle of nonmaleficence-"do no harm". Although exact risk remains uncertain, there is potential for significant donor morbidity and even mortality. 3. Careful consideration must be given to development of the best approach to obtaining truly informed consent. 4. Specific criteria for LDLT should be developed for transplant centers, donors, and recipients. Informed consent should be standardized. 5. A national registry for donors and recipients of LDLT is needed.

Managed care: effects on the physician-patient relationship

Over the past several years, healthcare has been profoundly altered by the growth of managed care. Because managed care integrates the financing and delivery of healthcare services, it dramatically alters the roles and relationships among providers, payers, and patients. While analysis of this change has focused on whether and how managed care can control costs, an increasingly important concern among healthcare providers and recipients is the impact of managed care on the physician–patient relationship. The literature includes a number of theoretical articles and anecdotal accounts of managed care's impact on the doctor–patient relationship, but little data have been collected and analyzed. We designed a survey for distribution to Wisconsin physicians to analyze the prevalence and types of managed care arrangements in the state, and the impact of these arrangements on physicians and their relationships with patients.

Recruitment maneuvers in three experimental models of acute lung injury. Effect on lung volume and gas exchange

Recruitment maneuvers (RM), consisting of sustained inflations at high airway pressures, have been advocated as an adjunct to mechanical ventilation in acute respiratory distress syndrome (ARDS). We studied the effect of baseline ventilatory strategy and RM on end-expiratory lung volume (EELV) and oxygenation in 18 dogs, using three models of acute lung injury (ALI; n = 6 in each group): saline lavage (LAV), oleic acid injury (OAI), and intratracheal instillation of Escherichia coli (pneumonia; PNM). All three models exhibited similar degrees of lung injury. The PNM model was less responsive to positive end-expiratory pressure (PEEP) than was the LAV or OAI model. Only the LAV model showed an oxygenation response to increasing tidal volume (VT). After RM, there were transient increases in Pa(O(2)) and EELV when ventilating with PEEP = 10 cm H(2)O. At PEEP = 20 cm H(2)O the lungs were probably fully recruited, since the plateau airway pressures were relatively high ( approximately 45 cm H(2)O) and the oxygenation was similar to preinjury values, thus making the system unresponsive to RM. Sustained improvement in oxygenation after RM was seen in the LAV model when ventilating with PEEP = 10 cm H(2)O and VT = 15 ml/kg. Changes in EELV correlated with changes in Pa(O(2)) only in the OAI model with PEEP = 10 cm H(2)O. We conclude that responses to PEEP, VT, and RM differ among these models of ALI. RM may have a role in some patients with ARDS who are ventilated with low PEEP and low VT.

Microbialite morphostratigraphy as a tool for correlating Late Cambrian-Early Ordovician sequences

Microbialite morphostratigraphy is a new tool for intrabasinal correlation using diverse microbialite structures (morphotypes). The recognition of the succession of morphotypes over constrained temporal intervals and broad areas is a function of the complex interactions that operate to create the structure. Because so many nonlinked variables (e.g., biotic, sedimentological, physicochemical) are involved, similar morphotypes do not reoccur over long temporal intervals. To demonstrate the technique, the upper Cambrian-lowermost Ordovician shelf strata of the Great Basin, United States, were correlated using both morphostratigraphy and standard lithostratigraphy. Six morphozones and one morphosubzone were recognized, as were four main lithologic successions. Because the boundaries between the morphozones and lithologic successions did not coincide, it is inferred that the characteristics of the various microbialite structures are not solely controlled by physical factors. The principles for establishing a morphostratigraphy outlined in this article allow for the potential to correlate along other ancient marine margins in both the same Cambrian and Ordovician interval, as well as any interval in the Phanerozoic in which diverse microbialite structures occur.

Prone positioning attenuates and redistributes ventilator-induced lung injury in dogs

BACKGROUND

We previously demonstrated a markedly dependent distribution of ventilator-induced lung injury in oleic acid-injured supine animals ventilated with large tidal volumes and positive end-expiratory pressure > or =10 cm H2O. Because pleural pressure distributes more uniformly in the prone position, we hypothesized that the extent of injury induced by purely mechanical forces applied to the lungs of normal animals might improve and that the distribution of injury might be altered with prone positioning.

OBJECTIVE

To compare the extent and distribution of histologic changes and edema resulting from identical patterns of high end-inspiratory/low end-expiratory airway pressures in both supine and prone normal dogs.

DESIGN/SETTING

We ventilated 10 normal dogs (5 prone, 5 supine) for 6 hrs with identical ventilatory patterns (a tidal volume that generated a peak transpulmonary pressure of 35 cm H2O when implemented in the supine position before randomization, positive end-expiratory pressure = 3 cm H2O). Ventilator-induced lung injury was assessed by gravimetric analysis and histologic grading.

MEASUREMENTS AND MAIN RESULTS

Wet weight/dry weight ratios (WW/DW) and histologic scores were greater in the supine than the prone group (8.8+/-2.8 vs. 6.1+/-0.7; p = .01 and 1.4+/-0.3 vs. 1+/-0.3; p = .037, respectively). In the supine group, WW/DW and histologic scores were significantly greater in dependent than nondependent regions (9.4+/-1.9 vs. 6.7+/-0.9; p = .01 and 2.0+/-0.4 vs. 0.9+/-0.4; p = .043, respectively). In the prone group, WW/DW also was greater in dependent regions (6.7+/-1.1 vs. 5.8+/-0.5; p = .054), but no significant differences were found in histologic scores between dependent and nondependent regions (p = .42).

CONCLUSION

In this model of lung injury induced solely by mechanical forces, the prone position resulted in a less severe and more homogeneous distribution of ventilator-induced lung injury. These results parallel those previously obtained in oleic acid-preinjured animals ventilated with higher positive end-expiratory pressure.

Lemierre syndrome in an immunocompromised patient

Lemierre syndrome or septic thrombophlebitis of the internal jugular vein is a potentially life-threatening complication. This condition may result from oropharyngeal infection, central venous catheterization, and intravenous drug abuse. Immunocompromised patients and individuals with systemic disease are at higher risk of developing the syndrome. We present here a case of septic jugular vein thrombosis in an adolescent with systemic lupus erythematosus. The etiological factors, pathogenesis, and diagnostic and therapeutic measures are discussed.

Small cis-acting sequences that specify secondary structures in a chloroplast mRNA are essential for RNA stability and translation

Nucleus-encoded proteins interact with cis-acting elements in chloroplast transcripts to promote RNA stability and translation. We have analyzed the structure and function of three such elements within the Chlamydomonas petD 5' untranslated region; petD encodes subunit IV of the cytochrome b(6)/f complex. These elements were delineated by linker-scanning mutagenesis, and RNA secondary structures were investigated by mapping nuclease-sensitive sites in vitro and by in vivo dimethyl sulfate RNA modification. Element I spans a maximum of 8 nucleotides (nt) at the 5' end of the mRNA; it is essential for RNA stability and plays a role in translation. This element appears to form a small stem-loop that may interact with a previously described nucleus-encoded factor to block 5'-->3' exoribonucleolytic degradation. Elements II and III, located in the center and near the 3' end of the 5' untranslated region, respectively, are essential for translation, but mutations in these elements do not affect mRNA stability. Element II is a maximum of 16 nt in length, does not form an obvious secondary structure, and appears to bind proteins that protect it from dimethyl sulfate modification. Element III spans a maximum of 14 nt and appears to form a stem-loop in vivo, based on dimethyl sulfate modification and the sequences of intragenic suppressors of element III mutations. Furthermore, mutations in element II result in changes in the RNA structure near element III, consistent with a long-range interaction that may promote translation.

Massive pneumatosis intestinalis: CT diagnosis

Pneumatosis cystoides intestinalis is a rare condition characterized by multiple subserosal or submucosal gas filled cysts within the wall of a segment of bowel. It is associated with numerous conditions, both intra and extraabdominal in nature. The condition may be asymptomatic or may present clinically as nausea, vomiting, diarrhea or other signs of intestinal obstruction. With rupture of the cysts, pneumoperitoneum may be a finding. In a patient with vague clinical presentation, this finding radiographically may lead to a clinical dilemma as many of these patients have comorbid conditions which are also associated with intestinal perforation. The authors present the case of a 47-year-old obese black female found to have massive pneumatosis intestinalis of the tranverse colon with a small amount of free intraperitoneal air. This case highlights the importance of recognizing pneumatosis intestinalis as a possible mimic of free intraabdominal air as well as a possible cause of benign pneumoperitoneum.

B cell lymphoproliferative disorders following hematopoietic stem cell transplantation: risk factors, treatment and outcome

Twenty-six cases of B cell lymphoproliferative disorder (BLPD) were identified among 2395 patients following hematopoietic stem cell transplants (HSCT) for which an overall incidence of BLPD was 1.2%. The true incidence was probably higher, since 9/26 of the diagnoses were made at autopsy. No BLPD was observed following autologous HSCT, so risk factor analyses were confined to the 1542 allogeneic HSCT. Factors assessed were HLA-mismatching (> or = 1 antigen), T cell depletion (TCD), presence of acute GvHD (grades II-IV), donor type (related vs unrelated), age of recipient and donor, and underlying disease. Factors found to be statistically significant included patients transplanted for immune deficiency and CML, donor age > or = 18 years, TCD, and HLA-mismatching, with recipients of combined TCD and HLA-mismatched grafts having the highest incidence. Factors found to be statistically significant in a multiple regression analysis were TCD, donor age and immune deficiency, although 7/8 of the patients with immunodeficiencies and BLPD received a TCD graft from a haploidentical parent. The overall mortality was 92% (24/26). One patient had a spontaneous remission, but subsequently died >1 year later of chronic GVHD. Thirteen patients received therapy for BLPD. Three patients received lymphocyte infusions without response. The only patients with responses and longterm survival received alpha interferon (alphaIFN). Of seven patients treated with alphaIFN there were four responses (one partial and three complete). These data demonstrate that alphaIFN can be an effective agent against BLPD following HSCT, if a timely diagnosis is made.

In re Edna MF: case law confusion in surrogate decision making

I review the recent case of Edna Folz, a 73 year-old woman who was suffering through the end stages of very advanced Alzheimer's dementia when her case was adjudicated by the Wisconsin Supreme Court. I consider this case as an example of how courts are increasingly misinterpreting the ethical and legal decision-making-standards known as "substituted judgment" and "best interests" and thereby threatening individuals' treatment decision-making rights as developed by other courts over the past two decades and creating serious roadblocks to health-care providers' ability to render appropriate patient care. The Wisconsin Supreme Court held that Edna's legal guardian could not authorize withdrawal of Edna's treatment, ruling that as a matter of law, if an incompetent person is not in a persistent vegetative state, it is not in his or her best interests for life-sustaining treatment to be withdrawn unless (s)he has executed an advance directive or other statement clearly indicating his or her desires.

The role of tacrolimus in adult kidney transplantation: a review

The use of tacrolimus (FK506) in adult kidney-transplant recipients has been the subject of a number of single- and multi-center studies. This review article focuses on those studies in which tacrolimus was used either as rescue therapy in patients who developed refractory rejection on cyclosporine (CyA)-based regimens or as primary immunosuppression in adult renal-allograft recipients. Twenty-five prospective and retrospective studies conducted in the US, Japan and Europe, including single- and multi-center experiences, were identified in the medical literature. Of these studies, most show a 74-98% initial success rate for tacrolimus rescue therapy. Comparative studies reviewed herein demonstrate comparable patient- and graft-survival rates between tacrolimus- and CyA-treated patients. Many studies have shown that rejection episodes occur with similar or lower frequency among patients treated with tacrolimus than among those given CyA as primary immunosuppression. The major toxicities associated with tacrolimus are nephrotoxicity, neurotoxicity and diabetogenicity. Results from several studies have also demonstrated an association between these tacrolimus side effects and high whole-blood trough levels of tacrolimus. In many cases, a reduction in dosage can reverse these adverse effects. In summary, based on both single- and multi-center data, tacrolimus has been demonstrated to be efficacious when used for either primary immunosuppression or as rescue therapy for refractory acute rejection in adult renal-allograft recipients.

Tissue harmonic imaging sonography: evaluation of image quality compared with conventional sonography

OBJECTIVE

The purpose of this study was to determine if tissue harmonic imaging (THI) sonography produced higher quality images than did conventional sonography.

SUBJECTS AND METHODS

A prospective study was performed on 89 patients to compare the image quality of THI sonography with that of conventional sonography. Each examination was performed using THI sonography (transmitted frequency, 2.0 MHz; received frequency, 4.0 MHz) and conventional sonography at 2.5 and 4.0 MHz. The pancreatic area was studied in 60 patients, and other anatomic areas were studied in 68 patients. The images were then graded for penetration, detail, and total image quality. Graders were unaware of the sonographic technique.

RESULTS

Of the 60 pancreatic examinations, THI sonography was the best technique for penetration in 45, detail in 54, and total image quality in 50. For the pancreas, THI sonography was significantly better than 2.5-MHz conventional sonography for penetration (p = .0002), detail (p < .0001), and total image quality (p < .0001). THI sonography was significantly better than 4.0-MHz conventional sonography for penetration (p < .0001), detail (p < .0001), and total image quality (p < .0001). Of the 68 examinations of other anatomic areas, THI sonography was the best technique for penetration in 42, detail in 57, and total image quality in 58. For other anatomic areas, THI sonography was significantly better than 2.5-MHz conventional sonography for penetration (p = .05), detail (p < .0001), and total image quality (p < .0001). THI sonography was significantly better than 4.0-MHz conventional sonography for penetration (p < .0001), detail (p < .0001), and total image quality (p < .0001).

CONCLUSION

The THI technique improved sonographic image quality.

Portal vein velocities measured by ultrasound: usefulness for evaluating shunt functioning following TIPS placement and TIPS revision

BACKGROUND

To assess the usefulness of following portal vein velocities by Doppler ultrasound in evaluating shunt functioning after transhepatic intrajugular portosystemic shunt (TIPS) placement and revision.

METHODS

We retrospectively analyzed 39 patients who underwent a TIPS procedure in the preceding 4 years. Portal vein (PV) velocities were measured by Doppler ultrasound before and after TIPS insertion and revision and were correlated with portosystemic gradients (PSG) measured at angiography.

RESULTS

Mean PV velocities increased from 18 +/- 6 cm/s before TIPS placement to 50 +/- 21 cm/s (p < 0.001) after TIPS placement, with corresponding decrease of mean PSG from 20 +/- 6 to 8 +/- 3 mmHg (p < 0.001). Mean PV velocities significantly increased from 24 +/- 6 to 43 +/- 14 cm/s after TIPS revision (p < 0.02), with decrease of PSG from 17 +/- 6 to 9 +/- 5 mmHg (p < 0.05). A significant correlation was found between all PV velocities and their corresponding PSG (Spearman r < 0.61, p < 0.001).

CONCLUSION

PV velocities significantly correlate with changes in PSG. Following portal vein velocities by ultrasound is useful for early evaluation of shunt functioning following TIPS.

Torsion of the fallopian tube: progression of sonographic features

Isolated torsion of the fallopian tube is a rare gynecologic condition that is difficult to diagnose preoperatively. We present the sonographic and CT findings over a 48-hour period in a case of isolated torsion of the fallopian tube. The radiologic features of isolated torsion have been described previously; however, to our knowledge, the progressive findings have not been previously reported.

Color Doppler applications in hepatic imaging

Color Doppler sonography is an important modality in the non-invasive evaluation of the liver. It is commonly used to evaluate vascular changes which accompany cirrhosis. Doppler techniques are also used to evaluate patients who have undergone liver transplantation or transjugular intrahepatic portosystemic shunt (TIPS) placement. This review describes the various applications of color Doppler in hepatic imaging.

Liver transplant rejection: value of hepatic vein Doppler waveform analysis

BACKGROUND

To determine whether abnormal hepatic vein Doppler tracings can be used to predict liver transplantation rejection.

METHODS

A total of 158 hepatic vein Doppler tracings were obtained on 93 postliver transplant patients (63 patients without rejection and 30 patients with biopsy-proven rejection). Hepatic vein Doppler tracings were scored according to an established grading system (0 = normal triphasic waveform, 1 = dampened waveform, with loss of flow reversal, 2 = completely flat waveform). The hepatic vein Doppler tracings were then correlated with biopsy findings.

RESULTS

In the group of 63 patients without rejection, 124 Doppler examinations were performed and graded as follows: 0 = 87 (70%), 1 = 31 (25%), and 2 = 6 (5%). In the group of 30 patients with biopsy-proven rejection, 34 Doppler examinations were performed and graded as follows: 0 = 16 (47%), 1 = 14 (41%), and 2 = 4 (12%). The sensitivity of abnormal hepatic vein Doppler tracings for detection of rejection was 53% and the specificity was 70%. The positive predictive value of an abnormal hepatic vein Doppler tracing was 33% and the negative predictive value of a normal Doppler tracing was 84%.

CONCLUSIONS

Abnormal hepatic vein Doppler tracings are observed in patients with and without liver transplant rejection. Abnormal tracings cannot be used to predict liver transplant rejection.

Cryotherapy of metastatic carcinoid tumors

BACKGROUND

To describe the use of hepatic cryotherapy to treat patients with symptomatic carcinoid metastates.

METHODS

Hepatic cryotherapy was performed on five patients with carcinoid syndrome resulting from metastatic carcinoid tumors. Intraoperative ultrasound was used to guide the cryotherapy and to assess the adequacy of freezing.

RESULTS

All five patients had relief of the carcinoid syndrome after treatment. In four of the five patients, the relief was prolonged (>3 months); in one patient, the relief of symptoms was transient (2 months). Four of five patients had a transient reduction in hormonal tumor markers (the fifth patient did not have hormonal-level follow-up). During a follow-up period of 2.5 years, four of the five patients died. The 6-month survival rate was 80%, the 1-year survival rate was 60%, the 2-year survival rate was 40%, and the 2.5-year survival was 20%. One patient is alive 30 months after treatment.

CONCLUSION

Hepatic cryotherapy can provide symptomatic relief for patients with hepatic metastates producing the carcinoid syndrome.

MRI findings in adenosquamous carcinoma of the gallbladder

In this report, we present the MRI findings of adenosquamous carcinoma of the gallbladder, a rare type of gallbladder malignancy. MRI examination not only helped established the diagnosis but also accurately depicted the extent of involvement of the adjacent liver. The ability to image in multiple planes was also useful in assessing the anatomic location of the tumor and in determining that the patient could be treated with surgical resection.

Underassessment of lower extremity deep venous thrombosis using color flow Doppler compared to compression sonography

The aim of this paper is to compare the accuracy of color Doppler to compression sonography in the diagnosis of lower extremity deep vein thrombosis. Longitudinal color flow imaging was performed in 60 lower extremities in patients with clinically suspected deep venous thrombosis (DVT). The study was then repeated by a blinded examiner using transverse compression sonography. The results were then correlated. Thirty-five examinations were negative by both color flow and compression methods. Twenty thrombi were diagnosed on compression sonography, while only 13 were diagnosed by the color flow method. Thirty-five percent of thrombi were missed using color flow imaging alone. We conclude that compression sonography should remain an integral part of the assessment of lower extremity DVT, as a significant number of thrombi might be overlooked using longitudinal color flow imaging alone. This is especially true in non-occlusive thrombi that are adherent to the vessel wall.

Wisconsin healthcare ethics committees

Over the past two decades ethics committees have proliferated in healthcare institutions across the country. Catalysts for this growth include the endorsement of ethics committees by the New Jersey Supreme Court in the Quinlan case, by the President's Commission for the Study of Ethical Problems in Medicine and Biomedical Research (“President's Commission”) in its report entitled Deciding to Forgo Life Sustaining Medical Treatment, by the U.S. Department of Health and Human Services in its 1985 “Baby Doe” regulations, by numerous other courts in treatment decisionmaking opinions issued after Quinlan, and more recently by the Joint Commission on Accreditation of Healthcare Organizations (JCAHO).

MRI of the liver. A pictorial essay

Magnetic resonance imaging (MRI) is an extremely useful modality for evaluation of the complex pathophysiology of the liver. The high degree of soft tissue contrast afforded by MRI accurately detects and characterizes both focal and diffuse abnormalities of the liver. In this article we present a pictorial review of MRI of the liver.

Successful correction of hemophagocytic lymphohistiocytosis with related or unrelated bone marrow transplantation

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening disorder of immune regulation leading to widespread lymphocytic and hemophagocytic infiltration of vital organs. Apparent cure has only been achieved with allogeneic bone marrow transplantation (BMT). This report describes 20 consecutive patients, who underwent either matched sibling donor (n = 4) or unrelated donor (URD; n = 16) BMT. Age at the time of BMT was 0.4 to 5.3 years (median, 0.8 years). Central nervous system disease was present at diagnosis in 13 patients. At BMT, 14 patients were in a clinical remission, whereas 6 patients had active HLH. All patients were engrafted after cytoreduction with busulfan, cyclophosphamide, and etoposide. The probability of grade II-III acute graft-versus-host disease (GVHD) for all patients was 57% (95% confidence limit [CL], 0.28, 0.86), and 73% (95% CL, 0.44, 1.0) in URD patients. The overall probability of survival at 3 years was 45% (95% CL, 0.23, 0.67) and 44% (95% CL, 0.19, 0.68) when URD BMT was evaluated separately. Favorable BMT outcome was associated with clinical remission status at the time of BMT. The preparative regimen was well tolerated, and in the 9 surviving patients it provided durable engraftment and was effective at eradicating the underlying disease.

CT diagnosis of acquired intercostal lung herniation

Intercostal lung herniation is a rare complication of trauma, best demonstrated by computed tomography. Most intercostal lung herniations are the result of direct trauma to the chest wall or occur at sites of prior percutaneously placed chest tubes. We present two cases of acquired intercostal lung herniation.

Ablative adenoidectomy: a new technique using simultaneous liquefaction/aspiration

OBJECTIVE

This study was performed to critically evaluate a new cautery technique for adenoidectomy that combines indirect visualization with complete hemostasis, ultimately permitting the surgeon to tailor the procedure to the patient's specific needs.

DESIGN

This prospective study of 138 consecutive adenoidectomy patients of the senior author was carried out at the Montreal Children's Hospital over 17 months. Concurrent adenoidectomy patients of another senior otolaryngologist in our institution as well as cases of the senior author using the conventional cold curettage technique served as controls.

METHOD

Data were collected preoperatively with respect to indication for surgery and radiologic findings. Operative findings including duration of surgery, concurrent procedures, position of adenoid hypertrophy, and blood loss were also recorded. Postoperative complications such as hemorrhage, infection, dehydration, as well as the incidence of velopharyngeal insufficiency and nasopharyngeal stenosis were also recorded up to 1 year from the date of surgery. The operative technique involves indirect visualization of the nasopharynx with a laryngeal mirror combined with cautery-liquefaction and suction ablation of the adenoid tissue.

RESULTS

Our results demonstrate a significant reduction in blood loss as well as a reduction in operative time. There was a low incidence of postoperative infection, no patients required a return to the operating room for hemostasis, and there were no cases of recurrent adenoid hypertrophy. There was no detectable difference in the incidence of postoperative complications.

CONCLUSION

We conclude that this technique is safe and time-efficient, with the advantages of excellent visualization and essentially no operative blood loss.

Influence of prone position on the extent and distribution of lung injury in a high tidal volume oleic acid model of acute respiratory distress syndrome

OBJECTIVE

To evaluate the influence of body position on the extent and distribution of experimental lung damage in an oleic acid canine model of acute respiratory distress syndrome, using mechanical ventilation with high tidal volumes and positive end-expiratory pressure (PEEP).

DESIGN

Prospective, randomized study.

SETTING

Experimental animal laboratory.

SUBJECTS

Twelve anesthetized and paralyzed dogs.

INTERVENTIONS

Ninety minutes after lung injury was induced by injection of oleic acid, 12 animals were randomized to be ventilated for 4 hrs, in either the supine (supine group, n = 6) or prone (prone group, n = 6) positions, using the same ventilatory pattern (F10(2) 0.6, PEEP > or = 10 cm H2O, and a tidal volume that generated a peak transpulmonary pressure of 35 cm H2O when implemented in the supine position). Regardless of randomization to position, the tidal volumes, F10(2), and PEEP were kept constant and the pulmonary artery occlusion pressure was maintained between 4 and 6 mm Hg for the duration of the study.

MEASUREMENTS AND MAIN RESULTS

At the end of the protocol, the lungs were excised for gravimetric determination (wet/dry weight ratio) and histologic examination (histologic score). Changes over time in the static pressure-volume curve of the lungs (obtained in the supine position) were also used as end-point variables. At baseline, hemodynamic and respiratory variables did not differ between groups. Just before randomization to position (90 mins after oleic acid injection), both groups presented similar lung static pressure-volume curves. Pulmonary artery occlusion pressure (4.3 +/- 1.9 vs. 4.8 +/- 1.3 mm Hg [supine vs. prone group]), cardiac output (4.1 +/- 0.4 vs. 5.2 +/- 1.3 L/min [supine vs. prone group]), and venous admixture (36.7 +/- 20.7% vs. 28.3 +/- 19.4% [supine vs. prone group]) were also not significantly (p > .05) different when measured in the supine position. At the end of the experiment, lung gravimetric data in the two experimental groups were not statistically different, suggesting a similar extent of edema. Histologic abnormalities, however, were less in the prone group than in the supine group (p < .01), due primarily to marked differences in extent and severity in the dependent regions of the lungs. Static lung compliance improved over time in the prone group (34 +/- 9 to 46 +/- 19 mL/cm H2O)(p = .02), but not in the supine group (34 +/- 6 to 36 +/- 6 mL/cm H2O).

CONCLUSIONS

After oleic acid-induced lung injury, animals ventilated with high tidal volume and PEEP undergo less extensive histologic change in the prone position than in the supine position. The prone position alters the distribution of histologic abnormalities.

CT appearance of the Syed-Neblett device for interstitial brachytherapy of gynecologic malignancies

Radiation therapy is an important adjuvant treatment for gynecological malignancies. However, the maximum amount of radiation treatment is limited by the side effects to the normal local tissue. We present a brief summary of the use and appearance of the Syed-Neblett intracavitary device. This device allows delivery of radioactive implants to a local tumor resulting in maximum dosage to tumor tissue, but limiting dosage to the surrounding normal tissue.

Renovascular hypertension

In current clinical practice, angiographic evaluation of patients with suspected renovascular hypertension usually follows clinical suspicion and positive captopril scintigraphy. Early digital angiography and percutaneous renal artery angioplasty have evolved as the accepted treatment pattern. Doppler sonography and MR angiography continue to be evaluated as potential methods of noninvasive screening.

Detection of hepatocellular carcinoma in cirrhotic patients: sensitivity of CT and ultrasonography

Patients with cirrhosis are at increased risk for the development of hepatocellular carcinoma. The heterogeneous hepatic parenchyma produced by cirrhosis makes detection of hepatomas more difficult. The purpose of this study was to determine the sensitivities of CT and ultrasonography for detecting hepatomas in cirrhotic patients. A retrospective analysis was performed of 733 patients who underwent liver transplantation at our institution. A study population of 21 patients was selected who met our inclusion criteria. The inclusion criteria required a pathologic diagnosis of hepatocellular carcinoma, pathologic evidence of cirrhosis, and contrast-enhanced CT and sonographic examinations performed within 1 week of each other. The sensitivities of CT and ultrasonography were determined by comparing the imaging findings with pathology findings from serially sectioned total hepatectomy specimens. A total of 40 hepatomas were detected pathologically in the 21 patients in our study population. CT identified 12 of 21 patients with hepatomas and detected 18 of 40 individual lesions (patient detection sensitivity = 57%, lesion detection sensitivity = 45%). Ultrasonography identified 14 of 21 patients with hepatomas and detected 21 of 40 individual lesions (patient detection sensitivity = 67%, lesion detection sensitivity = 51%). Combining the findings of CT and ultrasonography allowed identification of 17 of 21 patients with hepatomas and detection of 24 of 40 individual lesions (patient detection sensitivity = 80%, lesion detection sensitivity = 60%). We conclude that CT and ultrasonography have a low sensitivity for the detection of hepatocellular carcinoma in patients with cirrhosis.

Tracheal gas insufflation: catheter effectiveness determined by expiratory flush volume

Used adjunctively during mechanical ventilation, tracheal gas insufflation (TGI) improves CO2 elimination, principally by decreasing effective anatomic dead space. Continuing lung deflation at end- expiration raises the end-expiratory C02 concentration within the proximal airway, and could theoretically reduce the efficiency of a given catheter flow. To test this possibility, we designed a series of experiments that examined the influence of TGI delivery patterns on the efficiency of CO2 elimination. Using a gating device, catheter flow was delivered selectively during desired portions of expiration. Paralyzed, ventilated dogs were studied at short and extended inspiratory time fractions (TI/TT) with inspiratory tidal volume and ventilator frequency held constant. The expiratory flush volume, not the pattern of gas delivery, determined the observed decline in PaCO2, provided that the end-expiratory period was included in the catheter flush period. Despite continuing end-expiratory lung deflation (extended TI/TT), catheter effectiveness remained the same at matched expiratory flush volumes. To determine if enhanced distal mixing at the higher catheter flows required during the extended TI/TT (to match expiratory flush volume) masked a decrease in efficiency, we repeated the experiment with a tip-inverted catheter. We again found that matched catheter delivered expiratory volumes were similarly effective. With or without ongoing lung deflation, the volume of gas flushed during the expiratory period determined the effectiveness of TGI, provided that inspired minute ventilation remains unchanged and end-expiration is included in the catheter flush period.

Malignant neoplasms following bone marrow transplantation

We undertook an analysis of 2,150 recipients of bone marrow transplant (BMT) at the University of Minnesota to determine the incidence of post-BMT malignant neoplasms (MNs). Fifty-one patients developed 53 MNs, compared with 4.3 expected from general population rates (standardized incidence ratio [SIR], 11.6, 95% confidence interval [CI], 8.2-14.5). These included 22 occurrences of B-cell lymphoproliferative disorder (BLPD), 17 solid nonhematopoietic tumors, 10 myelodysplastic syndromes (MDS), 1 acute myelogenous leukemia (AML), 2 non-Hodgkin's lymphoma (NHL), and 1 Hodgkin's disease (HD). The estimated actuarial incidence of any post-BMT malignancy was 9.9% +/- 2.3% at 13 years posttransplant. The cumulative probability of BLPD plateaued at 1.6% +/- 0.3% by 4 years from transplant and factors independently associated with increased risk included in vitro T-cell depletion of marrow (relative risk (RR) = 11.9, P < .001), HLA mismatch (RR = 8.9, P < .001), use of antithymocyte globulin (ATG) for graft versus host disease (GVHD) prophylaxis (RR = 5.9, P < .001) or in the preparative regimen (RR = 3.1, P = .03) and primary immunodeficiency (RR = 2.5, P = .06). The cumulative probability of developing solid malignancy was 5.6% +/- 2.2% at 13 years from BMT. Malignant melanomas were the most common (SIR, 10.3, 95% CI 1.9 to 25.4). The actuarial incidence of MDS/AML plateaued at 2.1% +/- 0.8% at 9 years and was seen most often in older patients receiving autologous peripheral blood stem cells for HD or NHL. These data document that BMT recipients are at an increased risk of later malignancy, which may add significant morbidity and mortality to the transplant process. Methods for screening and identification of individuals at increased risk need to be addressed in future studies.

Systemic venous enhancement patterns during dynamic abdominal CT

In 25 patients we assessed the enhancement of abdominal venous structures during dynamic computed tomography (CT). The degree of venous enhancement demonstrated great variation. In six instances (out of 250 observations) a vessel was visually perceived as not enhancing and potentially thrombosed, including three gonadal veins. CT measurements were helpful in identifying enhancement, but were occasionally low enough that thrombosis remained a radiological consideration. The great variation in venous enhancement makes the diagnosis of thrombosis suspect, based on CT alone. Corroboration of this finding is suggested, when clinically relevant.

Treatment of head and neck hemangiomas with recombinant interferon alpha 2B

Fifteen patients with head and neck hemangiomas were treated with systemic recombinant interferon alpha 2b (rIFNalpha2b, Schering). There were 14 infants and 1 adult in the group, ranging in age from 5 weeks to 24 years old. Of the 15 patients in the group, 5 had involvement of the airway. Three of the patients had previously failed alternative systemic therapy. Twelve patients have had a beneficial response. Ten patients have completed the therapy and have been off interferon from 6 to 53 months without reappearance or progression of the disease. Two patients are currently on the therapy with resolving lesions. Three patients had minimal response and underwent successful surgical resection. No major toxicity was encountered during the therapy. Our experience demonstrates that rIFNalpha2b is a well-tolerated and effective therapy for hemangiomas of the head and neck that require intervention.

Health care providers' liability exposure for inappropriate pain management

Recent studies have exposed the startling inadequacy of health care providers knowledge about and practice of effective pain management. For example, in one study, it was reported that 79 percent of a random sample of 454 medical-surgical inpatients experienced pain during hospitalization, and that 58 percent of patients with pain considered the pain horrible or excruciating. In another study, 67 percent of 2,415 randomly selected hospitalized patients had pain during the twenty-four hours prior to being interviewed, and 50 percent reported pain at the time of the interview. In a study of seriously ill hospitalized patients reported in 1996, half of the patients complained of pain, and one-sixth reported that they experienced extremely severe pain at least half the time. According to one literature review, 75 percent of cancer patients have reported suffering pain, and one study estimates that 25 percent of cancer patients die with severe unrelieved pain. Chronic nonmalignant pain has been described as an extremely prevalent problem, and over two-thirds of nursing home residents experience serious pain.

A 24 year follow up of an isolated lymphangioma of the kidney

Renal lymphangioma is a rare benign tumor of the kidney. An example is presented which was initially identified by excretory urography, angiography and biopsy. A 24 year follow up included computed tomography. The radiographic findings, pathogenesis and natural history of this unusual tumor are discussed.

Abdominal aortic coarctation: CT, MRI, and angiographic correlation

Abdominal aortic coarctation is an uncommon entity in the elderly. We present a case of abdominal aortic coarctation with computed tomography (CT), magnetic resonance imaging (MRI) and conventional angiographic correlation. CT and MR imaging detected an abnormal abdominal aorta distal to the origin of the celiac axis with the diagnosis of abdominal aortic coarctation confirmed by conventional angiography. Clinical presentation and diagnostic imaging findings depend on the level of the coarctation and its relationship to the renal vessels.