Hsp90 orchestrates temperature-dependent Candida albicans morphogenesis via Ras1-PKA signaling

BACKGROUND

Hsp90 is an environmentally contingent molecular chaperone that influences the form and function of diverse regulators of cellular signaling. Hsp90 potentiates the evolution of fungal drug resistance by enabling crucial cellular stress responses. Here we demonstrate that in the leading fungal pathogen of humans, Candida albicans, Hsp90 governs cellular circuitry required not only for drug resistance but also for the key morphogenetic transition from yeast to filamentous growth that is crucial for virulence. This transition is normally regulated by environmental cues, such as exposure to serum, that are contingent upon elevated temperature to induce morphogenesis. The basis for this temperature dependence has remained enigmatic.

RESULTS

We show that compromising Hsp90 function pharmacologically or genetically induces a transition from yeast to filamentous growth in the absence of external cues. Elevated temperature relieves Hsp90-mediated repression of the morphogenetic program. Hsp90 regulates morphogenetic circuitry by repressing Ras1-PKA signaling. Modest Hsp90 compromise enhances the phenotypic effects of activated Ras1 signaling whereas deletion of positive regulators of the Ras1-PKA cascade blocks the morphogenetic response to Hsp90 inhibition. Consistent with the requirement for morphogenetic flexibility for virulence, depletion of C. albicans Hsp90 attenuates virulence in a murine model of systemic disease.

CONCLUSIONS

Hsp90 governs the integration of environmental cues with cellular signaling to orchestrate fungal morphogenesis and virulence, suggesting new therapeutic strategies for life-threatening infectious disease. Hsp90's capacity to govern a key developmental program in response to temperature change provides a new mechanism that complements the elegant repertoire that organisms utilize to sense temperature.

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.